Calorie restriction mimetics: can you have your cake and eat it, too?

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Ageing Research Reviews xxx (2014) xxx–xxx

Contents lists available at ScienceDirect

Ageing Research Reviews journal homepage: www.elsevier.com/locate/arr

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Review

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Calorie restriction mimetics: Can you have your cake and eat it, too?

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Donald K. Ingram a,∗ , George S. Roth b

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Nutritional Neuroscience and Aging Laboratory, Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, LA 70809, United States b GeroScience, Inc., Pylesville, MD 21132, United States

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a r t i c l e

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a b s t r a c t

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Article history: Received 23 April 2014 Received in revised form 25 November 2014 Accepted 25 November 2014 Available online xxx

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Keywords: Aging Metabolism Diet restriction Sirtuin mTOR Insulin

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Contents

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1. 2. 3. 4.

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Strong consensus exists regarding the most robust environmental intervention for attenuating aging processes and increasing healthspan and lifespan: calorie restriction (CR). Over several decades, this paradigm has been replicated in numerous nonhuman models, and has been expanded over the last decade to formal, controlled human studies of CR. Given that long-term CR can create heavy challenges to compliance in human diets, the concept of a calorie restriction mimetic (CRM) has emerged as an active research area within gerontology. In past presentations on this subject, we have proposed that a CRM is a compound that mimics metabolic, hormonal, and physiological effects of CR, activates stress response pathways observed in CR and enhances stress protection, produces CR-like effects on longevity, reduces age-related disease, and maintains more youthful function, all without significantly reducing food intake, at least initially. Over 16 years ago, we proposed that glycolytic inhibition could be an effective strategy for developing CRM. The main argument here is that inhibiting energy utilization as far upstream as possible provides the highest chance of generating a broad spectrum of CR-like effects when compared to targeting a singular molecular target downstream. As an initial candidate CRM, 2-deoxyglucose, a known anti-glycolytic, was shown to produce a remarkable phenotype of CR, but further investigation found that this compound produced cardiotoxicity in rats at the doses we had been using. There remains interest in 2DG as a CRM but at lower doses. Beyond the proposal of 2DG as a candidate CRM, the field has grown steadily with many investigators proposing other strategies, including novel anti-glycolytics. Within the realm of upstream targeting at the level of the digestive system, research has included bariatric surgery, inhibitors of fat digestion/absorption, and inhibitors of carbohydrate digestion. Research focused on downstream sites has included insulin receptors, IGF-1 receptors, sirtuin activators, inhibitors of mTOR, and polyamines. In the current review we discuss progress made involving these various strategies and comment on the status and future for each within this exciting research field. © 2014 Published by Elsevier B.V.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Defining a calorie restriction mimetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bariatric surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inhibitors of fat digestion/absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. Chitosan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Orlistat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3. Mannanoligosaccharides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inhibitors of carbohydrate digestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1. Acarbose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glycolytic inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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∗ Corresponding author. Tel.: +1 410 274 2656. E-mail addresses: [email protected] (D.K. Ingram), [email protected] (G.S. Roth). http://dx.doi.org/10.1016/j.arr.2014.11.005 1568-1637/© 2014 Published by Elsevier B.V.

Please cite this article in press as: Ingram, D.K., Roth, G.S., Calorie restriction mimetics: Can you have your cake and eat it, too? Ageing Res. Rev. (2014), http://dx.doi.org/10.1016/j.arr.2014.11.005

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6.1. 2-Deoxy-d-glucose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2. Glucosamine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3. Mannoheptulose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4. 3-Bromopyruvate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5. Iodoacetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6. Other candidates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Insulin signaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1. Metformin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Growth hormone/IGF1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Sirtuins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1. Resveratrol and sirtuin activating compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2. Nicotinamide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3. Oxaloacetic acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. mTOR inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Polyamines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12. Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. Introduction

Long considered the most robust paradigm in experimental gerontology, calorie restriction (CR) also known as diet restriction 58 (DR), involves restricting intake of a nutritious diet by 20–60% from 59 ad libitum levels (Fontana et al., 2010; Omodei and Fontana, 2011; 60 Chung et al., 2013). CR paradigms can differ from DR in terms of 61 finer control over macro–micro-nutrient composition of the diet; 62 whereas, DR can involve different regimens, such as intermittent 63 feeding. In numerous rodent studies, both types of intervention 64 can increase lifespan (both median and maximum) as well as 65 healthspan by retarding the onset and delaying the incidence of 66 age-related disease and maintaining physiological and behavioral 67 function later into life (Masoro, 2005; Bishop and Guarente, 2007; Fontana et al., 2010; Chung et al., 2013). For the purposes of this 68 review, we will refer to all studies as CR to simplify the discussion. 69 Studies in other vertebrate species, including dogs and monkeys, 70 have indicated beneficial effects of CR on indices of aging that por71 tend relevance to human aging (Fontana et al., 2010; Omodei and 72 Fontana, 2011). To this point, epidemiological studies of long-term 73 CR practitioners and short-term experimental studies of gradually 74 imposed CR have reported that reductions in risk factors for major 75 age-related diseases as well as improvements in putative biomark76 ers of aging are possible as well as feasible for human applications 77 (Fontana et al., 2010; Heilbronn et al., 2006; Weiss et al., 2006). 78 Nevertheless, even if evidence existed that life-long CR could pro79 duce similar beneficial effects in humans as observed in rodents, 80 implementation of this intervention would be highly problematic. 81 There would be major issues of compliance as well as other quality 82 of life issues impacted by CR, including thermoregulation, satiety, 83 84Q6 libido, and bone health (Dirks and Leeuwenburgh, 2006). Sustained research attention on the anti-aging mechanisms 85 induced by CR led to a new strategy to discover CR mimetics 86 (CRM: Weindruch et al., 2001; Hursting et al., 2003; Ingram et al., 87 2004; Roth et al., 2005; Ingram et al., 2006; Chen and Guarente, 88 2007; Ingram and Roth, 2011; Mercken et al., 2012; Selman, 2014). 89 Specifically, the objective is to identify compounds that mimic CR 90 by targeting metabolic and stress response pathways affected by 91 CR, but without actually restricting caloric intake (Ingram et al., 92 2006), at least in the early phases of the intervention. In 1998, 93 2-deoxyglucose (2DG) was proposed as the first candidate CRM 94 (Lane et al., 1998). Since that time the number of candidates 95 have expanded considerably as documented in previous reviews 96 (Ingram et al., 2004, 2006; Roth et al., 2005; Ingram and Roth, 2011; 97 Mercken et al., 2012; Selman, 2014). 98 In earlier reviews of the literature based on PubMed searches 99 with CRM or DRM as the primary descriptors, we found 21 cita100 tions in 2006 (Ingram et al., 2006) and 45 in 2011 (Ingram and 101 56Q5 57

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Roth, 2011). Currently we note over 75 such citations. Thus, the field has more than tripled in citations in just eight years. In this review we will again examine the major categories of proposed CRM and the research focused on their effects published to date. Because CR generates a wide range of beneficial effects, there are numerous mechanisms involved, and thus many candidate targets can be identified. What is clear at this juncture is that the field of CRM is expanding because the concept is compelling, and the discovery of effective CRM would represent a major breakthrough for gerontology that could have major biomedical relevance (Hursting et al., 2003; Ingram et al., 2004, 2006; Roth et al., 2005; Sinclair and Guarente, 2006; Chen and Guarente, 2007; Ingram and Roth, 2011; Mercken et al., 2012; Selman, 2014). 2. Defining a calorie restriction mimetic The concept of CRM has been evolving and has generated discussions within broad and narrow contexts. Within the broad context, discussions of CRM have pertained to virtually any intervention that produces benefits on aging, healthspan, and lifespan similar to those of CR. Such discussions have been made about antioxidants, hormones, metal chelators, and appetite suppressants. A recent paper suggested broadening the definition to include exercise (Huffman, 2010). During our earlier discussions (Ingram et al., 2004, 2006), we proposed a more narrowly defined concept entailing the following descriptors: (1) mimics the metabolic, hormonal, and physiological effects of CR; (2) activates stress response pathways observed in CR and enhances stress protection; (3) produces CR-like effects on longevity, reduces age-related disease, and maintains more youthful function; and (4) does not significantly reduce food intake, at least over the short-term. The latter is intended more as an experimental control rather than an absolute criterion. Interventions that reduce food intake are by that fact inducing CR; thus, it becomes difficult to ascertain that they are in fact “mimicking” CR unless careful pair-feeding studies are conducted. Nonetheless, with further regard to this criterion, we should now acknowledge that if a candidate CR mimetic alters body composition as expected, then it is highly likely, but not certain, that such an intervention might also result in reduced food intake over the long-term. Thus, the criterion of no significant effects on food intake should apply only to initial introduction of the intervention. In effect, though, the paradigm remains one of “Having your cake and eating it, too.” Another consideration of the suggested criteria is whether an effective CRM must demonstrate the ability to increase lifespan. CR has garnered such ample research attention because of this unique quality of extending median and maximum lifespan across a broad range of species. Recently, increased attention has been given to the benefits of candidate anti-aging interventions for extending


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Table 1 Calorie restriction mimetics: categories, candidate compounds, and putative targets.

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healthspan (Kirkland and Peterson, 2009; Tatar, 2009; Mercken et al., 2012). The Interventions Testing Program (ITP) sponsored by the National Institute on Aging (NIA) has brought badly needed standardization and rigor to the evaluation of anti-aging interventions (Miller et al., 2007; Nadon et al., 2008; Strong et al., 2008; Harrison et al., 2009, 2014; Miller et al., 2011, 2013; Strong et al., 2013). Based on the evaluation of over a dozen compounds to date, only one, rapamycin, has shown consistent effects on lifespan extension in both male and female mice (Harrison et al., 2009; Miller et al., 2011, 2013). Other candidates, such as aspirin and nordihydroguaiaretic acid, have demonstrated sex-specific benefits on lifespan (Strong et al., 2008). In previous studies, many of these interventions had shown beneficial effects on delaying age-related disease or functional declines, but they did not increase lifespan. One highly pertinent example was resveratrol, which benefited a wide range of healthspan measures, but did not extend lifespan in mice on a normal diet (Baur et al., 2006; Pearson et al., 2008; Strong et al., 2013). The ultimate goal for developing CRM is translation to human interventions. In this regard, while we can acknowledge that CR can induce physiological and molecular changes in humans that parallel findings in rodent CR studies and portend reduced risk of age-related disease and increased healthspan, we do not know, and might not ever know, if long-term CR in humans would extend lifespan. Moreover, addressing this question in closely related primate species has now yielded mixed results. The long-term study of rhesus monkeys at the University of Wisconsin reported significantly reduced morbidity and mortality in those monkeys maintained on 30% CR from adult ages (7–14 years of age) compared to controls (Colman et al., 2009, 2014). In contrast, a report from the longterm study of rhesus monkeys from the NIA that we initiated in 1987 found no evidence of improved survival in monkeys initiated

on 30% CR from young ages (2–6 years) or older ages (14–21 years) (Mattison et al., 2012). Differences in the design of these studies, particularly the dietary composition, are now being investigated to uncover reasons for the different outcomes. Even if the conclusion is ultimately that CR does not significantly extend lifespan in rhesus monkeys, there is ample evidence from these studies to demonstrate improved health and function at older ages in monkeys on CR. This emerging argument regarding whether CR can extend the lifespan of long-lived species will challenge the requirement that a CR mimetic must also extend lifespan. It will be highly interesting to observe how this argument unfolds over the next few years. Regarding current and future progress for developing CRM, we can first recognize that many dozens of possible targets exist to guide research. This statement is reinforced by two important points underlying this review: (1) Rather being driven through a single or a few vital genetic pathways, aging is manifested through the actions of multiple pathways; (2) Similarly CR mediates its anti-aging actions via multiple pathways. In past reviews we have proposed that discussion of targets guiding development of CRM can be efficiently organized by employing the concept of upstream and downstream targeting (Ingram et al., 2006; Ingram and Roth, 2011). In this light, our argument has remained that focusing on upstream targeting over downstream targeting will likely yield the most effective strategy for developing CRM. Thus, we contend that focusing on interventions that actually produce energy restriction would represent the most upstream targeting, and focusing on energy sensing systems would also be considered upstream targeting; whereas, downstream targeting would be those genes that respond to energy deficits. As outlined in Table 1, we discuss major categories of CRM and candidate compounds.


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3. Bariatric surgery The closest approximation to actual CR would be blocking absorption of food products that are converted to calories. Indeed, bariatric surgery is one means of reducing energy production by reducing the energy ingested from reaching circulation. The health benefits of this surgical intervention to treat obesity are now well documented (Kalyvas et al., 2013; Yip et al., 2013; Ricci et al., 2014; Ribaric et al., 2014). However, unknown are the benefits that would accrue following bariatric surgery in normal weight individuals. To this point, there have been a few reports that diabetes can be markedly ameliorated in slightly overweight individuals subjected to the surgery (García-Caballero et al., 2012). Furthermore, additional research has suggested that the health improvements observed following bariatric surgery result from many other responses to the surgery beyond mere reduction in energy absorbed (Bradley et al., 2012). Rodent models applying different techniques of bariatric surgery have also been developed that can be now be applied to questions about long-term effects on health and longevity (Seyfried et al., 2011). It is very clear that this intervention alters neural centers affecting satiety through alterations in gut peptide signaling to the brain (Berthoud et al., 2011; Madsbad et al., 2014). No long-term studies of bariatric surgery have been conducted in a mammalian model to determine whether this surgical intervention could prolong healthspan and lifespan. Moreover, even one of the inventors of bariatric techniques has recently noted the potential that exists for developing CRM (Miras and le Roux, 2014).

4. Inhibitors of fat digestion/absorption While it is clear that research on bariatric surgery is rapidly advancing and expanding, for the purposes of this review, we will cover pharmaceutical and nutraceutical interventions that relate to the development of CRM. Adhering to our intended organization of up-stream to down-stream targeting, we can next consider the strategy of reducing caloric intake by blocking intestinal absorption of fat. Three main types of compounds in this category have been investigated, including chitosan, tetrahydrolipstatin, and mannanoligosaccharides. Several of these have already undergone extensive clinical evaluation.

4.1. Chitosan Chitosan is a linear polysaccharide derived commercially by deacetylation of chitin obtained from the exoskeleton of crustaceans, typically crabs and shrimp and cell walls of fungi. With over a 100 references in PubMed, many clinical trials have been conducted using chitosan for a variety of conditions, most related to weight management and control of blood lipids. Three metaanalyses can be consulted to derive general conclusions. In a 2005 review, Mhurchu et al. analyzed 14 trials of weight loss using chitosan and concluded that there was some evidence of its efficacy with minimal side effects; however, if results of only the high quality trials were considered, reductions in body weight and blood lipids were minimal and likely not clinically significant. In a 2008 follow-up to that meta-analysis, Jull et al. (2008) examined 15 randomized, controlled trials with a minimum of 4 wks treatment with chitosan. They reached a similar conclusion as before: weight loss (mean of 1.7 kg) and cholesterol reductions (mean of −0.2 mmol/L) were minimal, but side effects were also minimal. In a 2009 review, Baker et al. examined six well controlled trials involving chitosan treatment in hypercholesterolemic patients and concluded that reductions in total cholesterol levels were significant (mean of

11.59 mg/dl), but treatment had no significant effects on lipid fractions. To date no long-term studies of chitosan have been conducted in a mammalian model to assess effects on healthspan and lifespan. One recent study examined effects of a 2% chitosan supplemented diet on blood lipids and redox enzymes fed to young (2–3 mo) and aged (20–25 mo) rats for 30 or 60 days (Anandan et al., 2013). These investigators reported that the chitosan diet attenuated age-associated dyslipidemia to restore redox balance observed as increased cardiac tissue levels of glutathione and glutathione reductase accompanied by reduced lipid peroxides. Interestingly aged rats on the chitosan diet exhibited reduced body weight, without a reduction in food intake. 4.2. Orlistat The second well-known fat blocker is Orlistat, or tetrahydrolipstatin, a compound which has undergone more rigorous clinical testing than products with chitosan. Indeed, it has qualified as a prescription treatment for obesity marketed by Roche as Xenical in most countries and as an over-the-counter medication, Alli, marketed by Glaxo Smith Kline in the US and UK. This compound is a saturated derivative of lipstatin, which is the natural inhibitor of pancreatic lipases (Zhi et al., 1995). Several meta-analyses have been published to review the literature on clinical studies using Orlistat. In a 2002 review of five early studies of obese, hypertensive patients, Sharma and Golay (2002) concluded that a 4-wk course of Orlistat could produce significant reductions in body weight (8 vs. 4%) and blood pressure and heart rate. In a 2003 review of 11 studies with over a 1-yr duration, Padwal et al. (2003) reported evidence of significant, but modest weight loss (2.9%). Rucker et al. (2007) reviewed 16 studies of 1-year duration and again confirmed the modest weight loss but expanded the list of positive effects to include significantly reduced blood cholesterol, LDL cholesterol, blood pressure and improved glycemic control in diabetic patients. Jacob et al. (2009) reviewed Orlistat trails in diabetic patients and concluded that treatment reduced body weight, blood glucose, and hemoglobin A1c (HbA1c) measures. Siebenhofer et al. (2009) reviewed trials in hypertensive patients of at least 24 wks and noted significant modest reductions in blood pressure (means of −2.5 mm SBP; −1.9 mm DBP). Reviewing 18 controlled studies of Orlistat with over 1-yr duration, Jacob et al. (2009) confirmed improved glycemic control in treated groups even when weight loss was minimum. Finally, in the most recent analysis, Zhou et al. (2012) confirmed the modest beneficial effects of Orlistat on body weight, blood pressure, fasting glucose, cholesterol and LDL cholesterol. In summary, abundant, generally well conducted, clinical trials have confirmed the beneficial health effects of Orlistat on body weight, blood lipids, blood pressure, and blood glucose. The major issue to downgrade these positive reports is the relatively high degree of side effects (36%), primarily gastrointestinal, including loose stools and excessive flatus, but also fecal incontinence. Examination of effects on survival or healthspan in humans or animal models has not been conducted with Orlistat. 4.3. Mannanoligosaccharides A third category of gut-centered interventions to consider is mannanoligosaccharides (MOS), which have been subjected to far less critical study than the previous fat blockers reviewed. These viscous fiber-like compounds are saccharide polymers that are widely used in animal feed, where they have developed a reputation for improving health and reducing mortality (Hooge, 2004). Human and rodent studies have generated evidence of reduced body weight and visceral fat without effects on food intake (Asano


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et al., 2004; Kumao et al., 2006; Takao et al., 2006). Mannan is a mannose-based polysaccharide found in many foods, including beans and coffee. One very popular Asian food is konjac manna (Amorphophallus konjac), from which glucomannans can be derived. A possible mechanism of action is due to the inability of mammals to cleave the ␤-1,4 linked sugar residues of the mannan backbone; thus, the polymers transit the upper gastro-intestinal (GI) tract undigested but undergo hydrolysis and uptake by colon bacteria in the colon. Here MOS and mannan have been reported to enhance gut population bifidobacteria species (Asano et al., 2004; Chen et al., 2008; Umemura et al., 2004). The effect on weight loss has been attributed to the fiber-fill effect and reduced fat uptake through the GI tract (Keithley and Swanson, 2005). There are some limited findings that these compounds can reduce blood lipids and glucose (Keithley and Swanson, 2005). Despite this evidence in humans, a recent mouse study using a human relevant dose of 1% MOS failed to confirm significant effects on body weight and fat in a 12-wk study (Smith et al., 2010). In contrast to this rodent study, more recent studies have reported beneficial effects using a proprietary product (PolyglycopleX) that reacts glucomannan with other soluble polysaccharides and adding it to the diet. A recent study in Zucker diabetic rats noted reductions in body weight, serum glucose, serum insulin, insulin resistance cholesterol, and liver steatosis over 12 wks (Grover et al., 2011). In study of a high sucrose diet in rats, Reimer et al. (2011) also reported body weight gain, lower serum triglycerides, and reduced liver steatosis over 8 wks. In addition, human studies of PolyglycopleX have reported reduced body weight, body fat, total cholesterol, and LDL in obese individuals treated for 14 wks, but this was not a placebo, controlled study (Lyon and Reichert, 2010). A small placebo controlled study in normal weight individuals did show reduced total cholesterol and LDL over 21 days of treatment with this product (Carabin et al., 2009). Two other controlled studies reported significantly improved glycemic response to a variety of foods when PolyglycopleX was consumed prior to the meal (Brand-Miller et al., 2010; Jenkins et al., 2010). Additionally, a recent study demonstrated dose-dependent increases in satiety measures in a small study of healthy subjects (Solah et al., 2014). Thus, further research with this product would appear to be warranted with larger controlled studies of longer duration. It should be noted, however, that similar to findings in studies of Orlistat, there are side effects noted in these studies using PolyglycopleX, which involve gastrointestinal symptoms. In summary, fat blockers as a strategy for developing CRM continue to have merit, although the results on body weight and composition as well as other blood parameters relevant to CR are modest at best. Moreover, there appear to be undesirable side effects to some of the products. Most critical to this review is that long-term animal studies have not been conducted to ascertain beneficial effects of these compounds on healthspan and lifespan.

5. Inhibitors of carbohydrate digestion 5.1. Acarbose Another strategy of gut intervention to affect energy availability is to target carbohydrate digestion to affect glucose availability. Acarbose (ACA) is a leading candidate for this approach. ACA inhibits glycoside hydrolases, the enzymes required to digest carbohydrates, specifically, alpha-glucosidase enzymes, in the brush border of the small intestines and also inhibits pancreatic alphaamylase (Derosa and Maffioli, 2012). The latter hydrolyzes complex

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starches to oligosaccharides in the lumen of the small intestine, and the membrane-bound intestinal alpha-glucosidases hydrolyze oligosaccharides, trisaccharides, and disaccharides to glucose and other monosaccharides in the small intestine. In effect, inhibiting these enzymes reduces the rate of digestion of complex carbohydrates resulting in less glucose being absorbed because carbohydrates are not broken down into glucose molecules. Although the overall effect of ACA treatment is a reduction in circulating glucose and HbA1c levels, the most impressive effect is reducing postprandial hyperglycemia (Derosa and Maffioli, 2012; Yang et al., 2014). In diabetic patients ACA has well-established history of use with many studies showing its effectiveness at decreasing blood glucose levels short-term and reducing HbA1c levels long-term. Most impressive is the ability of ACA to prevent postprandial hyperglycemia in these patients (Balfour and McTavish, 1993). Many rodent studies support this observation (Frantz et al., 2005; Kim et al., 2011; Miyamura et al., 2010). Additionally similar to CR, ACA has been shown to reduce body weight and body fat as well as improve age-related glucose dysregulation (Yamamoto and Otsuki, 2006). Interestingly, the CR-like results have been obtained with no reductions in food intake (Yamamoto and Otsuki, 2006). A recent study conducted by the ITP has demonstrated significant effects of ACA on longevity. Specifically, mice provided 1% ACA in their diet had significantly increased median and maximum lifespan, but to a much greater degree in males (Harrison et al., 2014). Body weight was reduced to a greater degree in males than in females on ACA diet. Interestingly, the diet did not significantly reduce HbA1c in the mice, while fasting blood glucose was increased. However, mice on the ACA diet had reduced plasma insulin and IGF-1 levels as well as an attenuated age-related decline in locomotor activity. Like metformin, to be discussed in a later section, ACA is now in widespread use for the treatment of diabetes; thus, its effects on healthspan and lifespan in human populations will be subject to many subsequent analyses. ACA is sold generically in Europe and China as Glucobay (Bayer) and in North America as Precose and in Canada as Prandase. Its popularity in China is much greater, likely due to a couple of major factors. First, effects of ACA appear to be higher in persons on high carbohydrate diets, as in Eastern diets. Second, side effects including diarrhea and increased flatulence are not uncommon among Western users, so the side effects often outweigh the benefits. However, large well-controlled studies of Eastern populations have found ACA to be safe and effective for diabetes and even prediabetes with equal effectiveness as metformin (Zhu et al., 2013; Zhang et al., 2013). 6. Glycolytic inhibition As the next step downstream from blocking energy availability and absorption at the gut level, we can consider blocking energy utilization at the cellular level. As a potentially potent target, we proposed the glycolytic pathway and have subsequently reinforced this proposal in other reports (Lane et al., 1998; Roth et al., 2005; Ingram et al., 2006; Ingram and Roth, 2011). The glycolytic pathway offers several points of intervention, specifically inhibition of the enzymes (hexokinase, phosphoglucose isomerase, and phosphofructokinase) involved in the conversion of glucose and glucose products to ATP. 6.1. 2-Deoxy-d-glucose As an initial approach, we proposed in 1998 to target phosphoglucose isomerase, the second step in this pathway (Lane et al.,


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1998). The candidate molecule was 2-deoxy-d-glucose (2DG) as it offered a well-established history as a glycolytic inhibitor. Moreover, the literature on 2DG offered several insights to indicate the potential of this compound as a CRM. Injections of 2DG had been shown to inhibit tumor growth, induce torpor, and increase circulating levels of glucocorticoids, all of which are hallmarks of CR (Ingram and Roth, 2011). In our first study of 2DG as a candidate CRM (Lane et al., 1998), we fed young male Fischer-344 (F344) rats diets supplemented (by weight) with 0.2%, 0.4%, or 0.6% 2DG to approximate doses of 100–150, 250–300, or 400–450 mg kg, respectively. The high dose turned out to be toxic which would be consistent with the Ushaped effects of CR on mortality. Nonetheless, at the lower doses the 2DG diets affected two important biomarkers of CR, but without significant effects on food intake. Specifically, plasma insulin and body temperature were reduced at the 0.4% dose. A persistent concern regarding glycolytic inhibition was the possibility of hyperglycemia; however, we saw no significant effects on plasma glucose levels. Since our initial study of 2DG, evidence from other studies strengthened its profile as a CRM. Several studies from Mark Mattson’s laboratory demonstrated 2DG protection against various in vivo and in vitro stressors similar to CR. Lee et al. (1999) demonstrated that 2DG protected against glutamate excitotoxicity in fetal hippocampal cells and produced evidence of an up-regulation of the stress response proteins, heat shock protein-70 (HSP-70) and glutamate responsive protein-78 (GRP-78). In another study, after rats were injected rats with 2DG for 12 weeks, Guo and Mattson (2000) found that cortical synaptosomes exhibited greater protection against iron and amyloid-peptides in vitro, and these synaptosome preparations also exhibited significantly elevated levels of HSP-70 and GRP-78 compared to controls. Yu and Mattson (1999) used a model of focal ischemia to demonstrate that 2DG treatment attenuated cerebral damage similar to the degree observed in CR. Applying a mouse model of Parkinson’s disease, Duan and Mattson (1999) reported that 2DG treated mice, compared to controls, exhibited less depletion of dopamine and faster behavioral recovery following treatment with the neurotoxin, 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine (MPTP), and levels of HSP-70 and GRP-78 were also increased in brains of treated mice. Feeding 2DG (0.4%) to Sprague-Dawley rats for 6 months, Wan et al. (2003) observed reduced serum glucose and insulin concentrations and increased ACTH and corticosterone levels, comparable to rats on a CR regimen. Applying telemetry, they also noted reduced levels of locomotor activity, heart rate, and blood pressure in 2DG treated rats comparable to responses in a CR group. In a later study, Wan et al. (2004) observed that 2DG-fed rats showed increased recovery from stress, measured as heart rate, blood pressure, and body temperature after restraint and cold water stress. Other investigations have noted additional parallels to CR when rats are treated with 2DG. For example, when rats are placed on short-term CR (e.g. 2 weeks), they exhibit increased dopaminerelated locomotor responses when challenged with injections of the dopamine agonist, amphetamine (Fuemayor and Diaz, 1984). In rats treated with 2DG, we have shown similar effects (Mamczarz et al., 2005). Specifically, rats on CR for 4 months exhibited enhanced locomotor response to amphetamine and that was replicated in rats fed 2DG (0.4%). Importantly these 2DG effects were produced without significant effects on food intake or body weight. Additionally, in a study using a transgenic mouse model of Alzheimer’s disease, the investigators reported that 2DG (0.04%) delivered in the diet for 7 weeks was able to attenuate amyloid pathology and increase levels of BDNF and NGF (Yao et al., 2011). Cancer research is an area that has had a rebirth of interest in glycolytic inhibition. Based on the classic Warburg effect (Warburg

et al., 1930), cancer cells are known to up-regulate glucose metabolism to support their propensity for rapid growth. Dependent upon cancer cell type, glycolytic enzymes are up-regulated while mitochondria production is down-regulated (Pedersen, 2007). Cancer cells can use this metabolic shift to gain an energetic advantage over normal cells because they do not need to depend on oxygen. Thus, similar to robust effects of CR on tumor induction and growth, glycolytic inhibition should be an effective anti-cancer intervention (Pedersen, 2007). Several studies had reported beneficial effects of 2DG injections on tumor growth (Gridley et al., 1985) prior to our proposal of 2DG as a CRM. The effectiveness of 2DG as an anti-tumor agent has been confirmed in several other studies. For example, Zhu et al. (2005) noted that 2DG markedly attenuated mammary tumor growth in female Sprague-Dawley rats induced by injection of 1-methyl-1-nitrosourea. Important to note is that these investigators used dietary concentrations of 0.02% and 0.03% 2DG after determining that the concentrations used in our first study (Lane et al., 1998) significantly inhibited body weight growth in this rat strain, while these lower concentrations did not. Nonetheless, these lower concentrations reduced serum insulin and raised serum corticosterone levels consistent with CR effects, but there no significant effects on glucose, leptin, or IGF-1 values. Utilizing cultures of cancer cells (MCF-7) treated with 2DG, these investigators also noted upregulation in important CR-related signaling pathways, specifically increased levels of phosphorylated AMPK and SIRT1. The ability of a compound to increase median and maximum lifespan would represent the highest standard of proof that it acts as a CRM. Regarding 2DG, this proof has been provided in the nematode model of aging in the lab of Michael Ristow. Schulz et al. (2007) treated worm cultures with various concentrations of 2DG and noted significant increases in lifespan that were dependent upon AMPK signaling (Schulz et al., 2007). In addition, these investigators proposed a major hypothesis of how glycolytic inhibition could provide the health benefits of CR. They described the concept of “mitohormesis”. This concept was supported by results showing short-term evidence of oxidative stress in response to 2DG that in turn induced an adaptive response to increase stress resistance. To support this hypothesis, they showed that the effects of 2DG on longevity could be eliminated when the worm cultures were provided antioxidant treatments, including N-acetyl-cysteine, vitamin C, or vitamin E. In effect, hormesis induces a mild stress can improve responses to greater stressors. There is expanding interest in the concept of hormesis as a major mechanism of CR (Calabrese, 2004; Mattson, 2008; Rattan, 2008), and this concept could apply to the actions CRM as well. In sum, an impressive literature has described marked parallels between CR and treatment with 2DG to strongly support its candidacy as a CRM (Kang and Hwang, 2006). Major caveats have emerged to attenuate this emerging positive profile. Specifically, we conducted toxicity studies and discovered the concentrations we had used (0.2–0.4%) produced cardiotoxicity in both F344 and Brown-Norway rats (Minor et al., 2010). Several aspects of the expected phenotype of a CRM were again reproduced in 2DG treated groups, including reduced blood levels of glucose and insulin as well as lower body temperature; however, cardiotoxicity was recorded in the form of vacuolarization of cardiac myocytes leading to heart failure in many rats involved in the long-term study. The cause of this pathology has not been established, and it was dose-dependent. These negative results can be contrasted to the positive results in other studies examining 2DG effects on cancer (Kang and Hwang, 2006) and Alzheimer’s disease (Yao et al., 2011) at lower doses than we used. Therefore, while discouraging to some degree, we must consider that 2DG could remain a viable candidate if the dose dependency of the toxicity can be fully established.


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A recent report has drawn considerable attention to a structure related to 2DG that represents a commonly used dietary supplement, d-glucosamine (GlcN), consumed to treat symptoms of osteoarthritis (Weimer et al., 2014). Acting through the hexosamine biosynthesis pathway, this monosaccharide (2-amino-2-deoxy-dglucose) serves as a precursor in synthesis of glycosylated proteins and lipids and is part of the structure of chitosan and chitin. Its application for treating osteoarthritis is because it is a precursor for glycosaminoglycans, which are major components of joint cartilage. However, beyond this application, GlcN is its phosphorylated form, GlcN-6-phosphate, acts as an inhibitor of hexokinase, with high activity, directed toward glucokinase, the isoform with heavy concentration in the liver. As described earlier, the Ristow lab first reported lifespan extension in nematodes using 2DG, which seemed to act via mitohormesis (Schulz et al., 2007). In their most recent paper, Weimer et al. demonstrate significant lifespan extension in nematodes treated with GlcN that appeared independent of the hexosamine pathway. Again as earlier, they noted evidence of mitohormesis as demonstrated by transient increases in mitochondrial ROS production. In this study, they expanded their studies into a mouse model and observed that aged mice (100 weeks old) had significantly increased lifespan, with no treatment effects on food intake or body composition, or energy expenditure. The one notable difference was reduced blood glucose under random fed, but not fasted, conditions. Gene array analysis in both species pointed to decreased glycolysis compensated by increased amino acid metabolism, linked to SKN-1/NRF-2-dependent transcription. Another recent study has provided evidence that GlcN activates autophagy (Caramés et al., 2013), an essential mechanism of cellular homeostasis that will be discussed in later sections. Given the impressive safety profile of this dietary supplement along with findings from a formal toxicity study in rats (Takahashi et al., 2009), this report on prolongevity effects of GlcN will undoubtedly spur new research examining its effects on healthspan.

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In a recent review of the CRM literature, we proposed further research of the glycolytic inhibitor, mannoheptulose (MH), as a candidate CRM (Ingram and Roth, 2011). In studies conducted during the 70s, MH was proposed as a treatment for hypoglycemia. When delivered IV at high doses, MH would produce huge spikes in glucose with a marked decrease in insulin. This action was considered to result from the inhibition of glycolysis in pancreatic ␤-cells. High doses of MH have also shown efficacy in rodent tumor models (Rasschaert et al., 2001; Ramirez et al., 2001). As a follow-up to work with 2DG, our interest is driven by the possibility of finding a compound that reduces insulin levels without producing hyperglycemia and without toxicity when given chronically. To this end, we began initial experiments to support that proposal using in vitro and in vivo cell models (Roth et al., 2009; Davenport et al., 2010). As a major advantage for translational purposes, these investigations have focused on an extract of unripened avocados found to contain high concentrations of this sugar. Preliminary reports support the safety and efficacy of an avocado extract enriched in MH when given to dogs. Of major interest was the dosedependent reduction in fasting insulin levels without increased glucose (Davenport et al., 2010).

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considerable interest is 3-bromopyruvate (3BP). As a simple lactic acid analog, a brominated derivative of pyruvic acid, 3BP acts to inhibit hexokinase II (HKII), the first step in glycolysis (Pedersen, 2007). While no studies have focused on this compound as a CRM for attenuating aging, many studies have examined its efficacy in a variety of tumor models. As mentioned earlier, the Warburg effect accounts for the increased glycolytic activities of many tumors and has thus generated interest in identifying HKII inhibitors for cancer treatment as many tumor lines greatly upregulate HKII activity and increase its binding to mitochondria (Pedersen, 2007). Ko et al. (2001) used a rabbit model of liver cancer to demonstrate a high level of HKII activity could be lowered markedly accompanied by an impressive reduction in tumor growth following IP 3BP treatment over the course of several days. When 3BP was delivered IV to rabbits, again these investigators noted even more impressive tumor size reductions with no evidence of pathology in other tissues. Using AS-30D hepatoma cells in a rat tumor model, Ko et al. (2004) noted similar efficacy against even to the point that most animals showed no residual signs of cancer. Other studies have noted the effectiveness of 3BP against leukemia cells (Xu et al., 2005). Hypothetically 3BP enters tumor cells via lactic acid transporters and inhibits HKII bound to mitochondria (Pedersen, 2007). Based on these results demonstrating its anti-tumor effects, 3BP could qualify as a candidate CRM, but further evaluation is clearly needed regarding long-term toxicity. While many previous studies have reported little or no toxicity related to 3BP treatment (Pedersen, 2007), a few studies have described issues. For example, one report noted dose-related toxicity to the liver and gastrointestinal tract in rabbits treated with 3BP via intra-arterial delivery in doses similar to those applied in previous studies (Chang et al., 2007). Second, ICV delivery of 3BP in rats can reduce brain metabolism, neurotransmitter function, particularly in the cholinergic system, and behavioral impairment (Froelich et al., 1995). Additionally, 3BP has been reported to negatively impact spermatozoal metabolism (Jones et al., 1996). All these effects, whether anti-tumor effects or negative effects on brain metabolism, are of course subject to dose response. We clearly understand that inhibition of energy production, or major suppression of ATP production, which could be an effective anti-tumor treatment, could be lethal for the cell and the animal. Thus, careful dose studies of 3BP are still required. Of note is that a patent for 3BP for cancer treatment has been approved and a company formed to promote its development (www.presciencelabs.com). Following marginal success in a single case clinical trial targeted to fibrolamellar hepatocellular carcinoma in young man (Ko et al., 2012), the company has implemented a Phase I clinical trial using 3BP. 6.5. Iodoacetate Several points of intervention exist for inhibiting glycolysis exist; thus, numerous candidates could be proposed as CRM. Targets could include glucose transporters as well as other enzymatic steps in glycolysis. As one example, iodoacetate acid is known to inhibit glyceraldehyde-3-phosphate dehydrogenase. In a preliminary in vitro analysis, pretreatment of fetal rat hippocampal neurons with iodoacetate provided protection against several stresses, including excessive glutamate, iron, and trophic factor withdrawal, while up-regulating heat shock proteins, HSP70 and HSP90 (Guo and Mattson, 2000). 6.6. Other candidates

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As mentioned above, the cancer field is also actively involved in identifying glycolytic inhibitors. One compound that has generated

To broaden this perspective, there are many other candidate HK inhibitors that can be explored to evaluate their efficacy as CRM. Moreover, other efforts to develop anti-cancer drugs have


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investigated other steps in the glycolytic pathway. For example, several inhibitors of catalytic subunit of glucose-6phosphatase have been suggested including ilicicolinic acid (B), oxodiperoxo(1,10-phenanthrolin)vanadate, and tetrahydrothienylpyridine (Parker, 2001). One strategy for these candidates would be to evaluate their individual efficacy but also in combination with other glycolytic inhibitors on various important endpoints beyond tumor inhibition. 7. Insulin signaling As the first-line downstream targets for developing CRM, we can consider insulin and IGF1 production, the insulin receptor, and its interaction with insulin signaling pathways (Anisimov, 2003; Bartke, 2008; Ingram et al., 2006; Tatar et al., 2003). This logic began to emerge in studies using invertebrate models in which genetic manipulation of the daf-2 pathway, which was considered a putative primitive insulin signaling pathway, achieved increased lifespan (Anisimov, 2003; Bartke, 2008; Tatar et al., 2003). One of the key biomarkers of CR is reduced plasma levels of insulin, which has also been reported to be predictive of longevity in healthy humans (Roth et al., 2002). 7.1. Metformin Biguanides represent a class of compounds that include phenformin, buformin, and metformin. The latter in particular has emerged as a strong candidate CRM (Onken and Driscoll, 2010; Anisimov, 2013). Since the 1950s, biguanides emerged as major anti-diabetic treatments due to their robust ability to reduce hyperglycemia, insulin, gluconeogenesis, intestinal glucose absorption, serum lipids and somatomedin. Phenformin had early success in many preclinical studies of aging. In several rodent studies, this compound was reported to increase lifespan and reduce cancer in mouse strains susceptible to tumors (Anisimov, 2003). Clinical use of phenformin and buformin, however, was halted because of reported problems with lactic acidosis observed in many patients (Anisimov, 2003). As a result, metformin has become the “go-to” drug for treating type 2 diabetes (Kirpichnikov et al., 2002). Acting through several mechanisms, metformin has been demonstrated in many longterm studies to improve the metabolic profile of diabetes. Among its actions are suppressed hepatic gluconeogenesis; enhanced peripheral glucose uptake; decreased absorption of glucose from the gastrointestinal tract; and increased fatty acid oxidation (Collier et al., 2006; Kim et al., 2008). Many of these actions have been shown to be driven by the activation of adenosine monophosphateactivated protein kinase (AMPK), which increases expression of small heterodimer protein (SHP), to inhibit expression of hepatic gluconeogenic genes, including phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (Collier et al., 2006; Kim et al., 2008). Other studies have shown that metformin might not act through AMPK (Foretz et al., 2010). AMPK activation also stimulates GLUT4 translocation to the plasma membrane to improve insulin independent glucose uptake. Increased peripheral glucose utilization results from improved insulin binding to insulin receptors (Bailey and Turner, 1996; Collier et al., 2006; Kim et al., 2008). A recent study has shown that metformin may decrease hepatic gluconeogenesis by non-competitively inhibiting the redox shuttle enzyme mitochondrial glycerophosphate dehydrogenase to produce an altered hepatocellular redox state that reduces the conversion of lactate and glycerol to glucose (Madiraju et al., 2014). Using a nematode model, De Haes et al. (2014) suggested that metformin produces mitohormesis acting via H2 O2 regulated by the peroxiredoxin PRDX-2 pathway.

Given the large scale use of metformin, many epidemiological studies have been able to analyze its long-term use and have noted increased survival from all-cause mortality in diabetic and cardiovascular disease patients (Eurich et al., 2005; Scarpello, 2003). There are also many reports of reduced incidence of age-related diseases, including cancer (Ben Sahra et al., 2010; Giovannucci et al., 2010; Boussageon et al., 2012) cardiovascular disease (Papanas and Maltezos, 2009) and chronic kidney disease (Pilmore, 2010). These findings describing robust anti-disease effects of metformin treatment provide evidence of its potential as a CRM. However, it should be acknowledged that a recent meta-analysis of metformin studies reported no significant over-all mortality benefit (Boussageon et al., 2012). As further support of its candidacy as a CRM, Dhahbi et al. (2005) reported that the transcriptional profile of mice treated with metformin for 8 weeks matched closely that produced by CR. In a series of studies using cancer-prone mouse strains, Anismov and colleagues observed positive effects of metformin treatment on lifespan (Anisimov et al., 2005, 2008, 2010a,b). Results in invertebrate models of aging have been mixed regarding beneficial effects of metformin. Using the nematode model and a variety of doses, Onken and Driscoll (2010) reported increased lifespan in metformin treated worm cultures, which was shown to require AMPK expression. Cabreiro et al. (2013) also demonstrated increased lifespan in nematode cultures treated with metformin, but this research team focused on the microbial folate and methionine metabolism as important mechanisms mediating its prolongevity effects. In the Drosophila model, Slack et al. (2012) observed AMPK activation in metformin treated flies, but there were no significant effects on lifespan. Indeed, at higher doses there was toxicity. In other rodent studies examining effects on longevity, we reported no significant effects of metformin (300 mg/kg) on lifespan of F344 rats; however, this finding was produced with only one dose of the drug (Minor et al., 2010). In a recent study in C57BL/6 mice using two doses of metformin (1% and 0.1% in the diets), a clear and contrasting dose response was observed (Martin-Montalvo et al., 2013). At the higher dose, survival was significantly reduced compared to controls; whereas, at the lower dose, survival was significantly increased even though the treated mice were consuming more food. In addition, the lower dose increased healthspan as indicated by a number of parameters measured at older ages, including improved glucose tolerance, increased treadmill endurance, better rotarod performance, higher levels of locomotor activity, and reduced incidence of cataracts. In sum, metformin remains at the top of the list of candidate CRMs; however, additional research is required to sort out the dose dependency of the effects on lifespan and healthspan. Given the drug’s widespread clinical use, research will expand and broaden over the next decade to examine effects on a wide range of agerelated conditions and diseases.

8. Growth hormone/IGF1 While reductions in growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in various animals have been reported, there is less consistency in the literature regarding effects of CR on this axis in humans (Longo and Fontana, 2010). A recent study of long-lived individuals found that longevity was associated with low serum levels of IGF-1 in females, but not in males; however, cancer survival was enhanced in both females and males with low IGF-1 levels (Milman et al., 2014). As demonstrated in dwarf mutant mice as well as in genetically engineered mice, however, manipulation of GH/IGF-1 axis can have profound effects on lifespan (Bartke, 2008; Kopchick et al., 2014). Excessive GH as produced in transgenic mice overexpressing GH as


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well as in the human condition, acromegaly, increases age-related diseases and mortality (Kopchick et al., 2014). A small group living in Ecuador with mutations in the GH receptor gene have the syndrome known as Laron dwarfism, with severe GHR and circulating IGF-1 deficiencies. These individuals show reduced risk for T2 diabetes, presumably due to the absence of the anti-insulinemic action of GH (Guevara-Aguirre et al., 2011). While these individuals also exhibit lower cancer incidence, they apparently do not live any longer than control subjects (Guevara-Aguirre et al., 2011). While no strong candidate CRM has yet emerged from this line of research, there is one drug to consider which is used very effectively to treat acromegaly. Pegvisomant (trade name Somavert) is an antagonist of the GH receptor that reduces production of IGF-1 (Kopchick et al., 2014). The drug appears to be highly efficacious and safe (Moore et al., 2009; Kopchick et al., 2014). It can normalize IGF1 levels in patients receiving chronic injections. Recently, there has been increased interest in its use in cancer therapy (Kopchick et al., 2014). The major deterrent to further investigation of pegvisomant as a candidate CRM is its prohibitive costs even for preclinical investigations, such as in the ITP. Additionally, timing treatment during the life course will be a difficult issue to address as well. Other, cheaper antagonists of the GH receptor may emerge to increase the number of candidates directed toward this target. In sum, current findings suggest that optimizing the IGF-1 axis to promote healthy aging in humans may be a complex proposition. Increased understanding of an array of interactions and tissue specificity will be required to advance the field and generate practical candidate CRMs directed toward GH/IGF1 targets (Milman et al., 2014).

9. Sirtuins Research involving the manipulation of sirtuins has represented the best example of downstream targeting as a strategy for developing CRM (Baur, 2010; Baur et al., 2006; Chen and Guarente, 2007; Howitz et al., 2003; Kume et al., 2010; Milne et al., 2007; Pearson et al., 2008; Wood et al., 2004). Led by David Sinclair and Lennard Guarente, this search has generated a massive amount of research on several fronts. Sirtris Pharmaceuticals was a company formed in 2004 to take the lead in developing this strategy. In 2008 the company was purchased by Glaxo Smith Kline (GSK). The strategy of the company was described as follows: “Our drug candidates are designed to mimic certain beneficial health effects of calorie restriction, without requiring a change in eating habits by activation of sirtuins, a recently discovered class of enzymes that control the aging process.”

9.1. Resveratrol and sirtuin activating compounds Identified through a compound screen to be an activator of SIRT1 in mammals and its invertebrate homolog, SIR2 (Howitz et al., 2003), the plant polyphenol, resveratrol, emerged as the lead compound for the initial research efforts of Sirtris. The potential of this compound to increase healthspan and lifespan has been investigated in a wide variety of studies (Baur, 2010). Early reports showed that adding resveratrol to the diet significantly increased median and maximum lifespan in invertebrate studies including yeast (Howitz et al., 2003), nematodes (Wood et al., 2004), and drosophila (Wood et al., 2004). Given that knock-out of SIR2 signaling was demonstrated to block effects of CR on lifespan in invertebrate models (Chen and Guarente, 2007; Wood et al., 2004), these findings provided strong evidence of the importance of signaling in this pathway for mediating effects of CR (Chen and Guarente, 2007; Sinclair and Guarente, 2006; Wood et al., 2004).

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Support of the postulated role of SIRT1 was more limited when these intervention studies were expanded to mammalian models. When fed to short-lived fish, resveratrol increased lifespan (Valenzano et al., 2006). When fed to middle-aged mice (12 mo) on a normal diet, however, a resveratrol supplemented diet did not increase mean or maximum lifespan (Baur et al., 2006; Pearson et al., 2008). Nonetheless, notable evidence was generated to reveal beneficial effects of the compound on healthspan. Specifically, mice fed resveratrol exhibited less cardiac pathology, greater bone health, reduced cataract incidence, and improved motor performance compared to mice on a control diet (Baur et al., 2006; Pearson et al., 2008). Moreover, there were clear benefits on survival in mice fed a high fat diet supplemented with resveratrol compared to mice on the same diet without resveratrol (Baur et al., 2006; Pearson et al., 2008). Healthspan was also increased in the resveratrol-fed mice measured by several indices in addition to a gene transcriptional profile that more closely resembled that of CR mice in this experiment than control fed mice (Pearson et al., 2008). Research examining the beneficial effects of resveratrol has been rapidly expanding. In rodent models resveratrol treatment has shown protection against a great variety of insults, including ischemic stroke (Sakata et al., 2010; Yousuf et al., 2009); heart failure (Yang et al., 2010), seizures (Gupta et al., 2002; Wu et al., 2009), Parkinson’s disease (Chao et al., 2008; Khan et al., 2010), and Alzheimer’s disease (Karuppagounder et al., 2009). In a rhesus monkey model, resveratrol treatment was effective in protecting against arterial stiffness and inflammation resulting from a high fat diet (Mattison et al., 2014). In human studies, resveratrol treatment has shown efficacy in improving memory performance in older subjects (Witte et al., 2014) and on reducing blood lipids and improve glucose regulation in obese subjects (Timmers et al., 2011) and adult diabetic subjects (Bhatt et al., 2012), but not in normal weight individuals (Yoshino et al., 2012). Moving beyond the research on resveratrol, the primary objective of Sirtris was to synthesize and characterize novel compounds that were direct activators of SIRT1, or STACs. Several candidate compounds were developed and subjected to preclinical studies with some moving forward to clinical studies primarily focused on diabetes (Milne et al., 2007; Feige et al., 2008; Lavu et al., 2008; Smith et al., 2009). The rationale for this focus is because aging is not a diagnostic entity recognized by the US FDA; therefore, pharmaceutical development for CRM must identify other appropriate targets. Given the robust effects of CR on the glucoregulation, diabetes is a logical target for these efforts. In contrast to the early robust findings examining resveratrol as a CRM, many negative reports also emerged describing failure to replicate the prolongevity effects of resveratrol in invertebrate models (Bass et al., 2007; Zou et al., 2009) or demonstrating increased lifespan independent of effects on SIRT1/2 (Aljada et al., 2010; Das et al., 2010). Other studies feeding resveratrol to rodents failed to replicate the pattern of gene expression stimulated by CR in mice (Barger et al., 2008). A major criticism arose that questioned the validity of the original assay used to identify resveratrol as a SIRT2/1 activator (Pacholec et al., 2010). This study argued that a technical artifact existed involving the fluorophore in the assay (Pacholec et al., 2010). These investigators argued that resveratrol did not directly activate SIRT1. Moreover, they claimed that the synthetic compounds developed by Sirtris did not activate the targeted gene (Schmidt, 2010). One compound, SIRT1720, also did not activate SIRT1 in vitro even after taking into account the possible assay confound. Additionally, this compound did not have any beneficial health effects in vivo when delivered to an ob/ob mouse model (Pacholec et al., 2010). Other studies provided evidence that the metabolic benefits of resveratrol were generated through inhibition of phosphodiesterase 4 (PDE4) leading to elevated levels of


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cAMP which increased signaling through the CamKK␤-AMPK pathway (Park et al., 2012). All these contradictory findings have generated intense arguments by many investigators from many sides (Das et al., 2010; Schmidt, 2010). Regarding the validity of the original assay, recent subsequent work by the Sinclair lab provided evidence that their original conclusions were correct. They demonstrated that SIRT1 was directly activated by resveratrol and other STACs via binding in the N-terminus of SIRT1 (Hubbard et al., 2013). Specifically, a mutation in this site (SIRT1-E230K) blocked activation by resveratrol and by STACs. Additionally, recent studies conducted in the de Cabo lab at NIA provided strong evidence of beneficial effects on lifespan and healthspan of the Sirtris compounds SRT1720 and SRT2104, in mice on both standard and high fat diets (Minor et al., 2011; Mitchell et al., 2014; Mercken et al., 2014). Beyond these arguments based on preclinical studies, the payoff for the STACs strategy has yet to be fully realized in clinical trials. Sirtris went forward with several randomized, placebo controlled, double-blind trials involving the compound, SRT2104. In an initial trial examining tolerability and pharmacokinetics, the compound was provided orally to healthy volunteers for 7 days and demonstrated safety and bioavailability (Hoffmann et al., 2013). In another initial study involving healthy elderly subjects, oral doses of this compound were provided for 28 days (Libri et al., 2012). Results supported safety of the treatment over this time period, with significant reductions in serum cholesterol, LDL and triglycerides, but no significant treatment effects on glucose responses. A similar 28day study was conducted in cigarette smokers and reported safety and efficacy regarding significant treatment-related reductions in serum cholesterol, LDL, and triglycerides and improved measures of blood flow (Venkatasubramanian et al., 2013). A recent 28-day study in adult diabetics again replicated the beneficial treatment effects on blood lipids but found no significant effects on glucose and insulin parameters (Baksi et al., 2014). Thus, while some beneficial results have emerged from these clinical trials regarding blood lipids, the original target of insulin sensitivity and glucose control have not been realized to date. GSK has begun new clinical trials of SRT2104 and other compounds focused on ulcerative colitis and psoriasis; however, the Cambridge headquarters of Sirtris was closed in 2013, although active research in sirtuin biology will continue. A major refocus of the field has moved interest away from activating SIRT1 to activation of SIRT3. This sirtuin is a protein located within the mitochondrial matrix and has been implicated in regulating metabolic processes, particularly oxidative stress via inhibition of components of the mitochondrial permeability transition pore (Onyango et al., 2002; Bause and Haigis, 2013; Kincaid and Bossy-Wetzel, 2013). One major driver of this interest was the report some years ago of a relationship between longevity in an older Italian cohort and alleles of SIRT3 (Bellizzi et al., 2005). Others have suggested a role of SIRT3 as a tumor suppressor protein, as mitochondria damaged by oxidative stress may trigger tumor development (Park et al., 2011). As evidence, mice with Sirt3 deleted develop breast mammary tumors (Kim et al., 2010). Someya et al. (2010) demonstrated that SIRT3 was essential for the actions of CR in attenuating age-related hearing loss in a mouse model.

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Research on the biology of sirtuins has also redirected attention to nicotinamide adenine dinucleotide (NAD) (Mouchiroud et al., 2013). By virtue of its role in redox balance, NAD is a central metabolic cofactor involved in numerous metabolic transformations. Sirtuins utilize NAD+ to deacetylate proteins, thus making its levels rate-dependent. Increasing levels of NAD+ represents a parallel strategy for activating sirtuins; however, there

is a clear dose-dependency since high levels can inhibit sirtuins (Mouchiroud et al., 2013). One strategy is providing nicotinamide. Notable progress has been made in preclinical studies using mouse models of Alzheimer’s disease. When nicotinamide is fed to mice over a several month period, there are significant reductions in amyloid and tau pathology and improvements in cognition (Green et al., 2008; Gong et al., 2013; Liu et al., 2013). Hypothesized mechanisms include increased activation of PGC1␣ to stimulate mitochondrial biogenesis (Gong et al., 2013) and increased autophagy to improve cellular health and function (Liu et al., 2013). A recent nematode study demonstrated lifespan extension in worms treated with nicotinamide; however, interestingly this effect was also observed in worms in which Sir-2 had been deleted. These investigators noted that nicotinamide underwent methylation and generated hydrogen peroxide via an aldehyde oxidase in mitochondria, which served as a hormetic signal to activate protective pathways to promote longevity in this model system (Schmeisser et al., 2013). In view of these findings, it is highly likely that many new investigations will elevate the candidacy of nicotinamide as a CRM. There is currently a clinical trial to evaluate its effects in patients with Alzheimer’s disease (www.clinicaltrials.gov/ct2/show/ NCT00580931). 9.3. Oxaloacetic acid Another strategy directed toward increasing levels of NAD+ to activate sirtuins is supplementation with oxaloacetic acid (OA). OA is a Kreb’s cycle intermediate that has been shown to increase levels of NAD+ and restore redox balance, NAD+/NADH (Cash, 2009). Treatment with OA has been demonstrated to reduce neural damage in rodent models of stroke (Campos et al., 2011), traumatic brain injury (Zlotnik et al., 2009, 2012) and seizures (Yamamoto and Mohanan, 2003), presumably by reducing oxidative stress. After showing benefits on glucose uptake in animal studies, Yoshikawa (1968) conducted a clinical study and reported reduced blood and urine levels of glucose in diabetic patients provided OA. Effects of OA on healthspan and lifespan have been not been extensive. In a nematode study, OA was shown to significantly increase lifespan acting through a AMPK pathway, but not involving SIR2 (Williams et al., 2009). Effects of OA supplementation on lifespan in mice were investigated by the ITP, which found no significant results; however, there were questions about whether effective blood levels of the compound were achieved (Strong et al., 2013). Developed as a nutraceutical product, OA is currently being marketed as a CRM (www.benegene.com). 10. mTOR inhibition Considering downstream targeting, mammalian target of rapamycin (mTOR) signaling has become a major focus of interest in developing CRM (Stanfel et al., 2009; Blagosklonny, 2010; Kapahi et al., 2010; Lamming et al., 2013). It was the debate over the centrality of SIRT1 in mediating the anti-aging effects of CR that generated this interest. Additionally, interest was rapidly growing in autophagy as a central cellular process involved in aging (Blagosklonny, 2010; Hands et al., 2006; Kapahi et al., 2010; Salminen and Kaarniranta, 2009; Stanfel et al., 2009; Lamming et al., 2013). mTOR is a serine/threonine protein kinase keenly involved in regulating cell survival, cell growth, cell proliferation, cell motility, cell protein synthesis and transcription (Hay and Sonenberg, 2004; Tokunaga et al., 2004) and autophagy (Hands et al., 2006; Salminen and Kaarniranta, 2009). The pathway is well positioned to sense cellular nutrient and energy levels and redox status to mediate the


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effects of CR (Tokunaga et al., 2004). mTOR can effectively integrate input from more upstream pathways, including insulin, IGF1, and mitogens (Hay and Sonenberg, 2004). Additional research has characterized what is now known to be the mTOR complex. mTOR complex 1 (mTORC1) is composed of mTOR, regulatory-associated protein of mTOR (Raptor), mammalian lethal with SEC13 protein 8 (MLST8) and the non-core components PRAS40 and DEPTOR (Kim et al., 2002, 2003). This complex operates as a nutrient/energy/redox sensor and control for protein synthesis (Kim et al., 2002; Hay and Sonenberg, 2004). mTORC1 activity can be stimulated by insulin, growth factors, serum, phosphatidic acid, amino acids (particularly leucine), and oxidative stress (Fang et al., 2001; Kim et al., 2002). mTOR Complex 2 (mTORC2) is comprised of mTOR, rapamycin-insensitive companion of mTOR (RICTOR), MLST8, and mammalian stress-activated protein kinase interacting protein 1 (mSIN1) (Sarbassov et al., 2004; Frias et al., 2006). The primary role of mTORC2 is to regulate the cytoskeleton through stimulation of F-actin stress fibers, paxillin, RhoA, Rac1, Cdc42, and protein kinase C ␣ (PKC␣) (Sarbassov et al., 2004). Additionally mTORC2 phosphorylates the serine/threonine protein kinase to affect metabolism and survival (Betz et al., 2013). Numerous, but not all, CR studies in animals have reported reduced mTOR (Blagosklonny, 2010; Tzatsos and Kandror, 2006). As strong evidence of its involvement, genetic downregulation of mTOR has been demonstrated to increase lifespan in many model systems, including yeast, worms, and flies (Blagosklonny, 2010; Sarbassov et al., 2004; Tzatsos and Kandror, 2006; Yang et al., 2006). The major boost in interest in rapamycin as a CRM came from the ITP study reporting in 2009 that pharmacological inhibition of mTOR signaling by dietary supplementation with rapamycin increased mean and maximum lifespan in heterogeneous mice begun on treatment at middle age (Harrison et al., 2009). Rapamycin, also known as sirolimus, is a FDA-approved drug used as an immunosuppressant to prevent organ transplantation rejection. The primary mechanism for this indication is to act on T-cells and B-cells and inhibit their response to IL-2. Regarding application as an anti-aging intervention, the hypothesized mechanism of rapamycin is the inhibition of mTOR to upregulate pathways involved in autophagy to remove damaged or misfolded proteins to prevent their aggregation (Tatar et al., 2003; Wang et al., 2005; Zemke et al., 2007). Several other mouse studies, including new ones from the ITP, replicated the positive effects of rapamycin on lifespan when added to the diet (Zhang et al., 2014; Fok et al., 2014; Wilkinson et al., 2012; Miller et al., 2013; Richardson, 2013) including mice on a high fat diet (Leontieva et al., 2014). Regarding effects on healthspan, some studies have come to different conclusions. In a recent study, Zhang et al. (2014) noted that rapamycin introduced late in life (19 mo) to B6 mice could increase lifespan and function as indicated by measures of gait and balance as well as several markers of pathology. In contrast, Neff et al. (2013) replicated the lifespan extension in rapamycin-treated mice as well as a few pathological markers, but noted few effects on functional measures that could be observed in aged mice exclusively; therefore, these investigators argued that the treatment did not retard aging. Studies focusing more on functional measures of aging have reported that rapamycin treatment can attenuate age-related declines in tests of cognitive performance in normal mice (Halloran et al., 2012; Majumder et al., 2012) as well as in mouse models of Alzheimer’s disease (Caccamo et al., 2010, 2013; Spilman et al., 2010; Ozcelik et al., 2013). Flynn et al. (2013) noted that RAPA treatment initiated late in life could improve cardiac function. Other studies have focused on the beneficial effects of RAPA on survival in cancer-prone mouse strains (Anisimov et al., 2010a,b, 2011). Rapamycin has a long history of interest in treatment of cancers (Ciuffreda et al., 2010; Sparks and Guertin, 2010). Many clinical

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trials are currently advancing, applying an analog of rapamycin, temsirolimus, in treating a variety of different tumors (Ciuffreda et al., 2010; Sparks and Guertin, 2010; Wang et al., 2005). Many argue that the appearance of anti-aging effects of RAPA emerging from longevity studies is due primarily to the effects of the compound on inhibiting cancer (Neff et al., 2013; Richardson, 2013). The other controversy challenging the development of RAPA as candidate CRM are the reported toxic effects observed in many mouse studies. Specifically, chronic RAPA treatment can produce insulin resistance, hyperlipidemia and glucose intolerance, increased incidence of cataracts, and also produce testicular degeneration (Houde et al., 2010; Chang et al., 2009; Fraenkel et al., 2008; Wilkinson et al., 2012; Neff et al., 2013). A recent study by Fang et al. (2013), noted that the negative metabolic responses were dependent upon time and duration of dosing. Specifically, when RAPA treatment was continued beyond 20 weeks, the negative effects on glucose/insulin metabolism were dissipated. Another concern about long-term rapamycin treatment at high doses is suppression of the immune system, making individuals more susceptible to dangerous infections. When given at low doses, RAPA treatment has been reported to enhance immune responses to tuberculosis (Jagannath and Bakhru, 2012). The solution to avoiding the negative effects of RAPA treatment will likely emerge from efforts to develop compounds that are more specific to mTORC1. While RAPA has strong affinity for mTORC1, detrimental effects on glucose/insulin metabolism have been linked to its inhibition of mTORC2 (Lamming et al., 2012). Despite these safety issues and complexity of responses observed with RAPA treatment, inhibition of mTOR has been clearly established as a leading target for development of CRM at a downstream site.

11. Polyamines The newest candidate CRM is the polyamine, spermidine (Minois et al., 2011; Minois, 2014). Polyamines are a ubiquitous group of polycationic aliphatic amines that serve multifunctional roles in the cell, many of which involve cell survival. In particular, spermidine is involved with numerous cellular processes (Ca2+ , Na+ , K+ -ATPase) that maintain membrane potential and control intracellular pH and volume. Spermidine is the source of many other polyamines, such as spermidine and thermospermine, that are involved in osmolality in many organisms. Spermidine is found in a wide variety of foods, including mushrooms, soy products, legumes, corn, whole grains, aged cheese, and wheat germ (Ali et al., 2011). The recent surge of interest in spermidine as a candidate CRM was generated by a 2009 paper from the Madeo lab in which lifespan was increased in a variety of invertebrate models (yeast, worms, flies) by spermidine treatments (Eisenberg et al., 2009). While there was evidence of reduced oxidative stress in these models as well as in mice treated with spermidine, the primary mechanism implicated was enhanced autophagy. Interestingly additional studies have indicated that spermidine induces autophagy independent of SIRT1 as well as independent of AMPK1/TOR pathway (Morselli et al., 2011). Apparently the main site for dictating an autophagic cascade is cytoplasmic deacetylation (Morselli et al., 2011). Nishimura et al. (2006) measured polyamine levels in different tissues from female mice at 3,10, and 26 weeks, and noted marked declines, particularly in spermidine in skin, thymus, spleen, ovary, liver, stomach, lung, kidney, heart and muscle. Age-related decline in serum spermidine concentrations have been noted in humans (Eisenberg et al., 2009), and a recent paper observed higher blood levels of spermidine in centenarians (Pucciarelli et al., 2012). To


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date, no reports of lifespan effects have emerged in mammalian models associated with spermidine treatment, although several are likely in progress. Soda et al. (2009) did feed Jc1:ICR mice a mixture of synthetic polyamines beginning at 24 weeks of age. At the highest dose, which yielded 374 and 1540 nmol/g of spermine and spermidine, respectively, the treatment increased survival and reduced the incidence of glomerulosclerosis without effects on bodyweight or food intake. Attenuation of age-related functional declines by spermidine treatment has been reported. Drosophila provided spermidineenriched diets showed enhanced memory performance at older ages compared to controls (Sigrist et al., 2014; Gupta et al., 2013). These investigators implicated increased autophagy as a primary mediator of these beneficial effects. Spermidine treatment has also improved performance in a number of different tasks in rodent models with a primary mechanism being its modulatory effects on the NMDA glutamate receptor (Gomes et al., 2010; Guerra et al., 2011, 2012). Application of spermidine treatment to other age-related conditions and diseases is also paying dividends. Spermidine provided health benefits in rodent models of diabetes (Tirupathi Pichiah et al., 2011), bone loss (Yamamoto et al., 2012), and arterial aging (LaRocca et al., 2013). Cancer is one important area of research that has seen little activity regarding spermidine treatment. In sum, it is highly likely that interest in spermidine treatment will continue to grow. The safety profile of this polyamine looks good, and the results thus far are encouraging regarding beneficial effects on a wide-range of age-related function and diseases.

12. Summary and conclusions The research field involving the development of CRM has been rapidly expanding over the last decade. Several companies have been formed to commercialize this concept, and a few products have been evaluated in clinical trials, and some are being marketed even without benefit of clinical trials. We reviewed numerous candidates encompassing upstream and downstream targeting strategies. Upstream targeting includes consideration of bariatric surgery, inhibitors of fat digestion/absorption, carbohydrate digestion, and glycolysis. Downstream targeting includes discussion of compounds affecting insulin receptors, IGF-1 receptors, sirtuin activators, inhibitors of mTOR, and polyamines. We have argued that upstream targeting should generate a broader and more robust range of CR-like effects acting through multiple mechanisms more than would be observed by downstream targeting exclusively (Ingram and Roth, 2011). Arguing against this contention are the reports describing a wide-range of beneficial effects of down-stream mTOR targeting, specifically by rapamycin treatment. While some of the sirtuin targeting strategy has lost its original luster, particularly in commercial applications, the field continues to evolve and has identified other possible targets, e.g. Sirt3, nicotinamide, and oxaloacetic acid. Many other topics could have been reviewed, including anorectic agents. We chose not to review this class of compounds because of the de facto issue of invoking CR through such intervention. Thus, while that strategy might prove ultimately successful (to date it has not), our original definition excluded consideration of such interventions. In addition, several other emerging targets, such as FGF21, were not discussed but are likely to continue to generate research activity (Mendelsohn and Larrick, 2012). In conclusion, despite growing interest and research in the concept, no proven CRM has yet to be identified, but several candidates appear highly promising. By arguing that CR induces beneficial effects through multiple signaling pathways, previously we have proposed the development of “cocktails” of CRM to affect multiple

systems (Roth et al., 2005; Ingram et al., 2006; Ingram and Roth, 2011). Many potential targets can be identified, and many new candidates, including cocktails of candidates, will surely be identified in the near future. References Ali, A.A., Poortvliet, E., Strömberg, R., Yngve, A., 2011. Polyamines in foods: development of a food database. Food Nutr. Res. 55, 5572. Aljada, A., Dong, L., Mousa, S.A., 2010. Sirtuin-targeting drugs: mechanisms of action and potential therapeutic applications. Curr. Opin. Investig. Drugs 11, 1158–1168. Anandan, R., Ganesan, B., Obulesu, T., Mathew, S., Asha, K.K., Lakshmanan, P.T., Zynudheen, A.A., 2013. Antiaging effect of dietary chitosan supplementation on glutathione-dependent antioxidant system in young and aged rats. Cell Stress Chaperones 18, 121–125. Anisimov, V.N., 2003. Insulin/IGF-1 signaling pathway driving aging and cancer as a target for pharmacological intervention. Exp. Gerontol. 38, 1041–1049. Anisimov, V.N., 2013. Metformin: do we finally have an anti-aging drug? Cell Cycle 15, 3483–3489. Anisimov, V.N., Berstein, L.M., Egormin, P.A., Piskunova, T.S., Popovich, I.G., Zabezhinski, M.A., Kovalenko, I.G., Poroshina, T.E., Semenchenko, A.V., Provinciali, M., Re, F., Franceschi, C., 2005. Effect of metformin on life span and on the development of spontaneous mammary tumors in HER-2/neu transgenic mice. Exp. Gerontol. 40, 685–693. Anisimov, V.N., Berstein, L.M., Egormin, P.A., Piskunova, T.S., Popovich, I.G., Zabezhinski, M.A., Tyndyk, M.L., Yurova, M.V., Kovalenko, I.G., Poroshina, T.E., Semenchenko, A.V., 2008. Metformin slows down aging and extends life span of female SHR mice. Cell Cycle 7, 2769–2773. Anisimov, V.N., Egormin, P.A., Piskunova, T.S., Popovich, I.G., Tyndyk, M.L., Yurova, M.N., Zabezhinski, M.A., Anikin, I.V., Karkach, A.S., Romanyukha, A.A., 2010a. Metformin extends life span of HER-2/neu transgenic mice and in combination with melatonin inhibits growth of transplantable tumors in vivo. Cell Cycle 9, 188–197. Anisimov, V.N., Zabezhinski, M.A., Popovich, I.G., Piskunova, T.S., Semenchenko, A.V., Tyndyk, M.L., Yurova, M.N., Antoch, M.P., Blagosklonny, M.V., 2010b. Rapamycin extends maximal lifespan in cancer-prone mice. Am. J. Pathol. 176, 2092–2097. Anisimov, V.N., Zabezhinski, M.A., Popovich, I.G., Piskunova, T.S., Semenchenko, A.V., Tyndyk, M.L., Yurova, M.N., Rosenfeld, S.V., Blagosklonny, M.V., 2011. Rapamycin increases lifespan and inhibits spontaneous tumorigenesis in inbred female mice. Cell Cycle 10, 4230–4236. Asano, I., Umemura, M., Fujii, S., Hoshino, H., Iino, H., 2004. Effects of mannooligosaccharides from coffee mannan on fecal microflora and defecation in healthy volunteers. Food Sci. Technol. Res. 10, 93–97. Bailey, C.J., Turner, R.C., 1996. Metformin. N. Engl. J. Med. 334, 574–579. Balfour, J.A., McTavish, D., 1993. Acarbose. An update of its pharmacology and therapeutic use in diabetes mellitus. Drugs 46, 1025–1054. Baker, W.L., Tercius, A., Anglade, M., White, C.M., Coleman, C.I., 2009. A meta-analysis evaluating the impact of chitosan on serum lipids in hypercholesterolemic patients. Ann. Nutr. Metab. 55, 368–374 (Nov 13, Epub). Baksi, A., Kraydashenko, O., Zalevkaya, A., Stets, R., Elliott, P., Haddad, J., Hoffmann, E., Vlasuk, G.P., Jacobson, E.W., 2014. A phase II, randomized, placebo-controlled, double-blind, multi-dose study of SRT2104, a SIRT1 activator, in subjects with type 2 diabetes. J. Clin. Pharmacol., http://dx.doi.org/10.1111/bcp.12327. Barger, J.L., Kayo, T., Vann, J.M., Arias, E.B., Wang, J., Hacker, T.A., Wang, Y., Raederstorff, D., Morrow, J.D., Leeuwenburgh, C., Allison, D.B., Saupe, K.W., Cartee, G.D., Weindruch, R., Prolla, T.A., 2008. A low dose of dietary resveratrol partially mimics caloric restriction and retards aging parameters in mice. PLoS ONE 3, e2264. Bartke, A., 2008. Insulin and aging. Cell Cycle 7, 3338–3344. Bass, T.M., Weinkove, D., Hourthoofd, K., Gems, D., Partridge, L., 2007. Effects of resveratrol on lifespan in Drosophila melanogaster and Caenorhabditis elegans. Mech. Ageing Dev. 128, 546–552. Baur, J.A., Pearson, K.J., Price, N.L., Jamieson, H.A., Lerin, C., Kalra, A., Prabhu, V.V., Allard, J.S., Lopez-Lluch, G., Lewis, K., Pistell, P.J., Poosala, S., Becker, K.G., Boss, O., Gwinn, D., Wang, M., Ramaswamy, S., Fishbein, K.W., Spencer, R.G., Lakatta, E.G., Le Couteur, D., Shaw, R.J., Navas, P., Puigserver, P., Ingram, D.K., de Cabo, R., Sinclair, D.A., 2006. Resveratrol improves health and survival of mice on a high-calorie diet. Nature 444, 337–342. Baur, J.A., 2010. Resveratrol, sirtuins, and the promise of a DR mimetic. Mech. Ageing Dev. 131, 261–269. Bause, AS1, Haigis, M.C., 2013. SIRT3 regulation of mitochondrial oxidative stress. Exp. Gerontol. 48, 634–639. Bellizzi, D., Rose, G., Cavalcante, P., Covello, G., Dato, S., De Rango, F., Greco, V., Maggiolini, M., Feraco, E., Mari, V., Franceschi, C., Passarino, G., De Benedictis, G., 2005. A novel VNTR enhancer within the SIRT3 gene, a human homologue of SIR2, is associated with survival at oldest ages. Genomics 85, 258–263. Ben Sahra, I., Le Marchand-Brustel, Y., Tanti, J.F., Bost, F., 2010. Metformin in cancer therapy: a new perspective for an old antidiabetic drug? Mol. Cancer Ther. 9, 1092–1099. Berthoud, H.R., Shin, A.C., Zheng, H., 2011. Obesity surgery and gut–brain communication. Physiol. Behav. 105, 106–119. Betz, C., Stracka, D., Prescianotto-Baschong, C., Frieden, M., Demaurex, N., Hall, M.N., 2013. mTOR complex 2-Akt signaling at mitochondria-associated endoplasmic


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reticulum membranes (MAM) regulates mitochondrial physiology. Proc. Natl. Acad. Sci. U. S. A. 110, 12526–12534. Bhatt, J.K., Thomas, S., Nanjan, M.J., 2012. Resveratrol supplementation improves glycemic control in type 2 diabetes mellitus. Nutr. Res. 32, 537–541. Bishop, N.A., Guarente, L., 2007. Genetic links between diet and lifespan: shared mechanisms from yeast to humans. Nat. Rev. Genet. 8, 835–844. Blagosklonny, M.V., 2010. Calorie restriction: decelerating mTOR-driven aging from cells to organisms (including humans). Cell Cycle 15, 683–688. Boussageon, R1, Supper, I., Bejan-Angoulvant, T., Kellou, N., Cucherat, M., Boissel, J.P., Kassai, B., Moreau, A., Gueyffier, F., Cornu, C., 2012. Reappraisal of metformin efficacy in the treatment of type 2 diabetes: a meta-analysis of randomised controlled trials. PLoS Med. 9 (4), e1001204, http://dx.doi.org/10.1371/journal.pmed.1001204. Bradley, D., Magkos, F., Klein, S., 2012. Effects of bariatric surgery on glucose homeostasis and type 2 diabetes. Gastroenterology 143, 897–912. Brand-Miller, J.C., Atkinson, F.S., Gahler, R.J., Kacinik, V., Lyon, M.R., Wood, S., 2010. Effects of PGX, a novel functional fibre, on acute and delayed postprandial glycaemia. Eur. J. Clin. Nutr. 64, 1488–1493. Cabreiro, F1, Au, C., Leung, K.Y., Vergara-Irigaray, N., Cochemé, H.M., Noori, T., Weinkove, D., Schuster, E., Greene, N.D., Gems, D., 2013. Metformin retards aging in C. elegans by altering microbial folate and methionine metabolism. Cell 28, 228–239. Caccamo, A., Magrì, A., Medina, D.X., Wisely, E.V., López-Aranda, M.F., Silva, A.J., Oddo, S., 2013. mTOR regulates tau phosphorylation and degradation: implications for Alzheimer’s disease and other tauopathies. Aging Cell 12, 370–380. Caccamo, A., Majumder, S., Richardson, A., Strong, R., Oddo, S., 2010. Molecular interplay between mammalian target of rapamycin (mTOR), amyloid-beta, and Tau: effects on cognitive impairments. J. Biol. Chem. 285, 13107–13120. Calabrese, E.J., 2004. Hormesis: from marginalization to mainstream: a case for hormesis as the default dose–response model in risk assessment. Toxicol. Appl. Pharmacol. 197, 125–136. Campos, F., Sobrino, T., Ramos-Cabrer, P., Argibay, B., Agulla, J., Pérez-Mato, M., Rodríguez-González, R., Brea, D., Castillo, J., 2011. Neuroprotection by glutamate oxaloacetate transaminase in ischemic stroke: an experimental study. J. Cereb. Blood Flow Metab. 31, 1378–1386. Carabin, I.G., Lyon, M.R., Wood, S., Pelletier, X., Donazzolo, Y., Burdock, G.A., 2009. Supplementation of the diet with the functional fiber PolyGlycoplex is well tolerated by healthy subjects in a clinical trial. Nutr. J. 8, 9. Caramés, B., Kiosses, W.B., Akasaki, Y., Brinson, D.C., Eap, W., Koziol, J., Lotz, M.K., 2013. Glucosamine activates autophagy in vitro and in vivo. Arthritis Rheum. 65, 1843–1852. Cash, A., 2009. Oxaloacetic acid supplementation as a mimic of calorie restriction. Open Longev. Sci. 3, 22–27. Chang, J.M., Chung, J.W., Jae, H.J., Eh, H., Son, K.R., Lee, K.C., Park, J.H., 2007. Local toxicity of hepatic arterial infusion of hexokinase II inhibitor, 3-bromopyruvate: in vivo investigation in normal rabbit model. Acad. Radiol. 14, 85–92. Chang, G.R., Wu, Y.Y., Chiu, Y.S., Chen, W.Y., Liao, J.W., Hsu, H.M., Chao, T.H., Hung, S.W., Mao, F.C., 2009. Long-term administration of rapamycin reduces adiposity, but impairs glucose tolerance in high-fat diet-fed KK/HlJ mice. Basic Clin. Pharmacol. Toxicol. 105, 188–198. Chao, J., Yu, M.S., Ho, Y.S., Wang, M., Chang, R.C., 2008. Dietary oxyresveratrol prevents parkinsonian mimetic 6-hydroxydopamine neurotoxicity. Free Radic. Biol. Med. 45, 1019–1026. Chen, D., Guarente, L., 2007. SIR2: a potential target for calorie restriction mimetics. Trends Mol. Med. 13, 64–71. Chen, H.L., Cheng, H.C., Wu, W.T., Liu, Y.J., Liu, S.Y., 2008. Supplementation of konjac glucomannan into a low-fiber Chinese diet promoted bowel movement and improved colonic ecology in constipated adults: a placebo-controlled, dietcontrolled trial. J. Am. Coll. Nutr. 27, 102–108. Chung, K.W., Kim, D.H., Park, M.H., Choi, Y.J., Kim, N.D., Lee, J., Yu, B.P., Chung, H.Y., 2013. Recent advances in calorie restriction research on aging. Exp. Gerontol. 48, 1049–1053. Ciuffreda, L., Di Sanza, C., Incani, U.C., Milella, M., 2010. The mTOR pathway: a new target in cancer therapy. Curr. Cancer Drug Targets 10, 484–495. Collier, C.A., Bruce, C.R., Smith, A.C., Lopaschuk, G., Dyck, D.J., 2006. Metformin counters the insulin-induced suppression of fatty acid oxidation and stimulation of triacylglycerol storage in rodent skeletal muscle. Am. J. Physiol. Endocrinol. Metab. 291, E182–E189. Colman, R.J., Beasley, T.M., Kemnitz, J.W., Johnson, S.C., Weindruch, R., Anderson, R.M., 2014. Caloric restriction reduces age-related and all-cause mortality in rhesus monkeys. Nat. Commun. 1 (5), 3557. Colman, R.J., Anderson, R.M., Johnson, S.C., Kastman, E.K., Kosmatka, K.J., Beasley, T.M., Allison, D.B., Cruzen, C., Simmons, H.A., Kemnitz, J.W., Weindruch, R., 2009. Science 325, 201–204. Das, D.K., Mukherjee, S., Ray, D., 2010. Resveratrol and red wine, healthy heart and longevity. Heart Fail. Rev. 15, 467–477. Davenport, G., Massimino, S., Hayek, M., Burr, J., Michael Ceddia, M., Yeh, C.-H., Roth, G., Ingram, D., 2010. Biological activity of avocado-derived mannoheptulose in dogs. Exp. Biol. (Abstract 725.4). De Haes, W., Frooninckx, L., Van Assche, R., Smolders, A., Depuydt, G., Billen, J., Braeckman, B.P., Schoofs, L., Temmerman, L., 2014. Metformin promotes lifespan through mitohormesis via the peroxiredoxin PRDX-2. Proc. Natl. Acad. Sci. U. S. A. 111, E2501–E2509. Derosa, G., Maffioli, P., 2012. Efficacy and safety profile evaluation of acarbose alone and in association with other antidiabetic drugs: a systematic review. Clin. Ther. 34, 1221–1236.

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Dhahbi, J.M., Mote, P.L., Fahy, G.M., Spindler, S.R., 2005. Identification of potential caloric restriction mimetics by microarray profiling. Physiol. Genomics 23, 343–350. Dirks, A.J., Leeuwenburgh, C., 2006. Caloric restriction in humans: potential pitfalls and health concerns. Mech. Ageing Dev. 127, 1–7. Duan, W., Mattson, M.P., 1999. Dietary restriction and 2-deoxyglucose administration improve behavioral outcome and reduce degeneration of dopaminergic neurons in models of Parkinson’s disease. J. Neurosci. Res. 57, 195–206. Eisenberg, T., Knauer, H., Schauer, A., Büttner, S., Ruckenstuhl, C., Carmona-Gutierrez, D., Ring, J., Schroeder, S., Magnes, C., Antonacci, L., Fussi, H., Deszcz, L., Hartl, R., Schraml, E., Criollo, A., Megalou, E., Weiskopf, D., Laun, P., Heeren, G., Breitenbach, M., Grubeck-Loebenstein, B., Herker, E., Fahrenkrog, B., Fröhlich, K.U., Sinner, F., Tavernarakis, N., Minois, N., Kroemer, G., Madeo, F., 2009. Induction of autophagy by spermidine promotes longevity. Nat. Cell Biol. 11, 305–314. Eurich, D.T., Majumdar, S.R., McAlister, F.A., Tsuyuki, R.T., Johnson, J.A., 2005. Improved clinical outcomes associated with metformin in patients with diabetes and heart failure. Diabetes Care 28, 2345–2351. Fang, Y., Vilella-Bach, M., Bachmann, R., Flanigan, A., Chen, J., 2001. Phosphatidic acid-mediated mitogenic activation of mTOR signaling. Science 294, 1942–1945. Fang, Y., Westbrook, R., Hill, C., Boparai, R.K., Arum, O., Spong, A., Wang, F., Javors, M.A., Chen, J., Sun, L.Y., Bartke, A., 2013. Duration of rapamycin treatment has differential effects on metabolism in mice. Cell Metab 217, 456–462. Feige, J.N., Lagouge, M., Canto, C., Strehle, A., Houten, S.M., Milne, J.C., Lambert, P.D., Mataki, C., Elliott, P.J., Auwerx, J., 2008. Specific SIRT1 activation mimics low energy levels and protects against diet-induced metabolic disorders by enhancing fat oxidation. Cell Metab 8, 347–358. Flynn, J.M., O’Leary, M.N., Zambataro, C.A., Academia, E.C., Presley, M.P., Garrett, B.J., Zykovich, A., Mooney, S.D., Strong, R., Rosen, C.J., Kapahi, P., Nelson, M.D., Kennedy, B.K., Melov, S., 2013. Late-life rapamycin treatment reverses agerelated heart dysfunction. Aging Cell 12, 851–862. Fok, W.C., Chen, Y., Bokov, A., Zhang, Y., Salmon, A.B., Diaz, V., Javors, M., Wood 3rd, W.H., Zhang, Y., Becker, K.G., Pérez, V.I., Richardson, A., 2014. Mice fed rapamycin have an increase in lifespan associated with major changes in the liver transcriptome. PLOS ONE 9 (1), e83988. Fontana, L., Partridge, L., Longo, V.D., 2010. Extending healthy life span—from yeast to humans. Science 328, 321–326. Foretz, M., Hébrard, S., Leclerc, J., Zarrinpashneh, E., Soty, M., Mithieux, G., Sakamoto, K., Andreelli, F., Viollet, B., 2010. Metformin inhibits hepatic gluconeogenesis in mice independently of the LKB1/AMPK pathway via a decrease in hepatic energy state. J. Clin. Invest. 120, 2355–2369. Fraenkel, M., Ketzinel-Gilad, M., Ariav, Y., Pappo, O., Karaca, M., Castel, J., Berthault, M.F., Magnan, C., Cerasi, E., Kaiser, N., Leibowitz, G., 2008. mTOR inhibition by rapamycin prevents beta-cell adaptation to hyperglycemia and exacerbates the metabolic state in type 2 diabetes. Diabetes 57, 945–957. Frantz, S., Calvillo, L., Tillmanns, J., Elbing, I., Dienesch, C., Bischoff, H., Ertl, G., Bauersachs, J., 2005. Repetitive postprandial hyperglycemia increases cardiac ischemia/reperfusion injury: prevention by the alpha-glucosidase inhibitor acarbose. FASEB J. 19, 591–593. Frias, M., Thoreen, C., Jaffe, J., Schroder, W., Sculley, T., Carr, S., Sabatini, D., 2006. mSin1 is necessary for Akt/PKB phosphorylation, and its isoforms define three distinct mTORC2s. Curr. Biol. 16, 1865–1870. Froelich, L., Ding, A., Hoyer, S., 1995. Holeboard maze-learning deficits and brain monoaminergic neurotransmitter concentrations in rats after intracerebroventricular injection of 3-bromopyruvate. Pharmacol. Biochem. Behav. 51, 917– 922. Fuemayor, L.D., Diaz, S., 1984. The effect of feeding on the stereotyped behaviour induced by amphetamine and by apomorphine in the albino rat. Eur. J. Pharmacol. 99, 153–158. García-Caballero, M., Valle, M., Martínez-Moreno, J.M., Miralles, F., Toval, J.A., Mata, J.M., Osorio, D., Mínguez, A., 2012. Resolution of diabetes mellitus and metabolic syndrome in normal weight 24–29 BMI patients with one anastomosis gastric bypass. Nutr. Hosp. 27, 623–631. Giovannucci, E., Harlan, D.M., Archer, M.C., Bergenstal, R.M., Gapstur, S.M., Habel, L.A., Pollak, M., Regensteiner, J.G., Yee, D., 2010. Diabetes and cancer: a consensus report. CA. Cancer J. Clin. 60, 207–221. Gomes, GM1, Mello, C.F., da Rosa, M.M., Bochi, G.V., Ferreira, J., Barron, S., Rubin, M.A., 2010. Polyaminergic agents modulate contextual fear extinction in rats. Neurobiol. Learn. Mem. 93, 589–595. Gong, B., Pan, Y., Vempati, P., Zhao, W., Knable, L., Ho, L., Wang, J., Sastre, M., Ono, K., Sauve, A.A., Pasinetti, G.M., 2013. Nicotinamide riboside restores cognition through an upregulation of proliferator-activated receptor-␥ coactivator 1␣ regulated ␤-secretase 1 degradation and mitochondrial gene expression in Alzheimer’s mouse models. Neurobiol. Aging 34, 1581–1588. Green, K.N., Steffan, J.S., Martinez-Coria, H., Sun, X., Schreiber, S.S., Thompson, L.M., LaFerla, F.M., 2008. Nicotinamide restores cognition in Alzheimer’s disease transgenic mice via a mechanism involving sirtuin inhibition and selective reduction of Thr231-phosphotau. J. Neurosci. 28, 11500–11510. Gridley, D.S., Nutter, R.L., Kettering, J.D., Mantik, D.W., Slater, J.M., 1985. Mouse neoplasia and immunity: effects of radiation, hyperthermia, 2-deoxy-d-glucose, and Corynebacterium parvum. Oncology 42, 391–398. Grover, G.J., Koetzner, L., Wicks, J., Gahler, R.J., Lyon, M.R., Reimer, R.A., Wood, S., 2011. Effects of the soluble fiber complex PolyGlycopleX on glucose homeostasis and body weight in young Zucker diabetic rats. Front. Pharmacol. (September), 47. Guerra, G.P., Mello, C.F., Bochi, G.V., Pazini, A.M., Fachinetto, R., Dutra, R.C., Calixto, J.B., Ferreira, J., Rubin, M.A., 2011. Hippocampal PKA/CREB pathway is involved in


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the improvement of memory induced by spermidine in rats+. Neurobiol. Learn. Mem. 96, 324–332. Guerra, G.P., Mello, C.F., Bochi, G.V., Pazini, A.M., Rosa, M.M., Ferreira, J., Rubin, M.A., 2012. Spermidine-induced improvement of memory involves a cross-talk between protein kinases C and A. J. Neurochem. 122, 363–373. Guevara-Aguirre, J., Balasubramanian, P., Guevara-Aguirre, M., Wei, M., Madia, F., Cheng, C.W., Hwang, D., Martin-Montalvo, A., Saavedra, J., Ingles, S., de Cabo, R., Cohen, P., Longo, V.D., 2011. Growth hormone receptor deficiency is associated with a major reduction in pro-aging signaling, cancer, and diabetes in humans. Sci. Transl. Med. 3, 70ra13. Guo, Z., Mattson, M.P., 2000. In vivo 2-deoxyglucose administration preserves glucose and glutamate transport and mitochondrial function in cortical synaptic terminals after exposure to amyloid ␤-peptide and iron: evidence for a stress response. Exp. Neurol. 166, 173–179. Gupta, V.K., Scheunemann, L., Eisenberg, T., Mertel, S., Bhukel, A., Koemans, T.S., Kramer, J.M., Liu, K.S., Schroeder, S., Stunnenberg, H.G., Sinner, F., Magnes, C., Pieber, T.R., Dipt, S., Fiala, A., Schenck, A., Schwaerzel, M., Madeo, F., Sigrist, S.J., 2013. Restoring polyamines protects from age-induced memory impairment in an autophagy-dependent manner. Nat. Neurosci. 16, 1453–1460. Gupta, Y.K., Briyal, S., Chaudhary, G., 2002. Protective effect of trans-resveratrol against kainic acid-induced seizures and oxidative stress in rats. Pharmacol. Biochem. Behav. 71, 245–249. Halloran, J., Hussong, S.A., Burbank, R., Podlutskaya, N., Fischer, K.E., Sloane, L.B., Austad, S.N., Strong, R., Richardson, A., Hart, M.J., Galvan, V., 2012. Chronic inhibition of mammalian target of rapamycin by rapamycin modulates cognitive and noncognitive components of behavior throughout lifespan in mice. Neuroscience 223, 102–113. Hands, S.L., Proud, C.G., Wyttenbach, A., 2006. mTOR’s role in ageing: protein synthesis or autophagy? Aging (Milano) 20, 586–597. Harrison, D.E., Strong, R., Sharp, Z.D., Nelson, J.F., Astle, C.M., Flurkey, K., Nadon, N.L., Wilkinson, J.E., Frenkel, K., Carter, C.S., Pahor, M., Javors, M.A., Fernandez, E., Miller, R.A., 2009. Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature 460, 392–395. Harrison, D.E., Strong, R., Allison, D.B., Ames, B.N., Astle, C.M., Atamna, H., Fernandez, E., Flurkey, K., Javors, M.A., Nadon, N.L., Nelson, J.F., Pletcher, S., Simpkins, J.W., Smith, D., Wilkinson, J.E., Miller, R.A., 2014. Acarbose, 17-␣-estradiol, and nordihydroguaiaretic acid extend mouse lifespan preferentially in males. Aging Cell 13, 273–282. Hay, N., Sonenberg, N., 2004. Upstream and downstream of mTOR. Genes Dev. 18, 1926–1945. Heilbronn, L.K., de Jonge, L., Frisard, M.I., DeLany, J.P., Larson-Meyer, D.E., Rood, J., Nguyen, T., Martin, C.K., Volaufova, J., Most, M.M., Greenway, F.L., Smith, S.R., Deutsch, W.A., Williamson, D.A., Ravussin, E., Pennington CALERIE Team, 2006. Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: a randomized controlled trial. J. Am. Med. Assoc. 295, 1539–1548. Hoffmann, E., Wald, J., Lavu, S., Roberts, J., Beaumont, C., Haddad, J., Elliott, P., Westphal, C., Jacobson, E., 2013. Pharmacokinetics and tolerability of SRT2104, a first-in-class small molecule activator of SIRT1, after single and repeated oral administration in man. Br. J. Clin. Pharmacol. 75, 186–196. Hooge, D.M., 2004. Turkey pen trials with dietary mannan oligosaccharide: metaanalysis, 1993–2003. Int. J. Poultry Sci. 3, 179–188. Houde, V.P., Brûlé, S., Festuccia, W.T., Blanchard, P.G., Bellmann, K., Deshaies, Y., Marette, A., 2010. Chronic rapamycin treatment causes glucose intolerance and hyperlipidemia by upregulating hepatic gluconeogenesis and impairing lipid deposition in adipose tissue. Diabetes 59, 1338–1348. Howitz, K.T., Bitterman, K.J., Cohen, H.Y., Lamming, D.W., Lavu, S., Wood, J.G., Zipkin, R.E., Chung, P., Kisielewski, A., Zhang, L.L., Scherer, B., Sinclair, D.A., 2003. Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan. Nature 425, 191–196. Hubbard, B.P., Gomes, A.P., Dai, H., Li, J., Case, A.W., Considine, T., Riera, T.V., Lee, J.E., E, S.Y., Lamming, D.W., Pentelute, B.L., Schuman, E.R., Stevens, L.A., Ling, A.J., Armour, S.M., Michan, S., Zhao, H., Jiang, Y., Sweitzer, S.M., Blum, C.A., Disch, J.S., Ng, P.Y., Howitz, K.T., Rolo, A.P., Hamuro, Y., Moss, J., Perni, R.B., Ellis, J.L., Vlasuk, G.P., Sinclair, D.A., 2013. Evidence for a common mechanism of SIRT1 regulation by allosteric activators. Science 339, 1216–1219. Huffman, D.M., 2010. Exercise as a calorie restriction mimetic: implications for improving healthy Aging and longevity. Interdiscip. Top. Gerontol. 37, 157– 174. Hursting, S.D., Lavigne, J.A., Berrigan, D., Perkins, S.N., Barrett, J.C., 2003. Calorie restriction, aging, and cancer prevention: mechanisms of action and applicability to humans. Annu. Rev. Med. 54, 131–152. Ingram, D.K., Anson, R.M., de Cabo, R., Mamczarz, J., Zhu, M., Mattison, J., Lane, M.A., Roth, G.S., 2004. Development of calorie restriction mimetics as a prolongevity strategy. Ann. N.Y. Acad. Sci. 1019, 412–423. Ingram, D.K., Zhu, M., Mamczarz, J., Zou, S., Lane, M.A., Roth, G.S., de Cabo, R., 2006. Calorie restriction mimetics: an emerging research field. Aging Cell 5, 97–108. Ingram, D.K., Roth, G.S., 2011. Glycolytic inhibition as a strategy for developing calorie restriction mimetics. Exp. Gerontol. 46, 148–154. Jacob, S., Rabbia, M., Meier, M.K., Hauptman, J., 2009. Orlistat 120 mg improves glycaemic control in type 2 diabetic patients with or without concurrent weight loss. Diabetes Obes. Metab. 11, 361–371. Jagannath, C., Bakhru, P., 2012. Rapamycin-induced enhancement of vaccine efficacy in mice. Methods Mol. Biol. 821, 295–303. Jenkins, A.L., Kacinik, V., Lyon, M., Wolever, T.M., 2010. Effect of adding the novel fiber, PGX® , to commonly consumed foods on glycemic response, glycemic index

and GRIP: a simple and effective strategy for reducing post prandial blood glucose levels—a randomized, controlled trial. Nutr. J. 9, 58. Jones, A.R., Porter, K.E., Dobbie, M.S., 1996. Renal and spermatozoal toxicity of alphabromohydrin, 3-bromolactate and 3-bromopyruvate. J. Appl. Toxicol. 16, 57–63. Jull, A.B., Ni Mhurchu, C., Bennett, D.A., Dunshea-Mooij, C.A., Rodgers, A., 2008. Chitosan for overweight or obesity. Cochrane Database Syst. Rev. 3 (July), CD003892. Kalyvas, A.V., Vlachos, K., Abu-Amara, M., Sampalis, J.S., Glantzounis, G., 2013. Bariatric surgery as metabolic surgery for diabetic patients. Curr. Pharm. Des. (Sep 12, Epub ahead of print). Kang, H.T., Hwang, E.S., 2006. 2-Deoxyglucose: an anticancer and antiviral therapeutic, but not any more a low glucose mimetic. Life Sci. 78, 1392–1399. Kapahi, P., Chen, D., Rogers, A.N., Katewa, S.D., Li, P.W., Thomas, E.L., Kockel, L., 2010. With TOR, less is more: a key role for the conserved nutrient-sensing TOR pathway in aging. Cell Metab 11, 453–465. Karuppagounder, S.S., Pinto, J.T., Xu, H., Chen, H.L., Beal, M.F., Gibson, G.E., 2009. Dietary supplementation with resveratrol reduces plaque pathology in a transgenic model of Alzheimer’s disease. Neurochem. Int. 54, 111–118. Keithley, J., Swanson, B., 2005. Glucomannan and obesity: a critical review. Altern. Ther. Health Med. 11, 30–34. Khan, M.M., Ahmad, A., Ishrat, T., Khan, M.B., Hoda, M.N., Khuwaja, G., Raza, S.S., Khan, A., Javed, H., Vaibhav, K., Islam, F., 2010. Resveratrol attenuates 6hydroxydopamine-induced oxidative damage and dopamine depletion in rat model of Parkinson’s disease. Brain Res. 1328, 139–151. Kim, D., Sarbassov, D., Ali, S., King, J., Latek, R., Erdjument-Bromage, H., Tempst, P., Sabatini, D., 2002. mTOR interacts with raptor to form a nutrient-sensitive complex that signals to the cell growth machinery. Cell 110, 163–175. Kim, D., Sarbassov, D., Ali, S., Latek, R., Guntur, K., Erdjument-Bromage, H., Tempst, P., Sabatini, D., 2003. GbetaL, a positive regulator of the rapamycin-sensitive pathway required for the nutrient-sensitive interaction between raptor and mTOR. Mol. Cell 11, 895–904. Kim, J.H., Kang, M.J., Choi, H.N., Jeong, S.M., Lee, Y.M., Kim, J.I., 2011. Quercetin attenuates fasting and postprandial hyperglycemia in animal models of diabetes mellitus. Nutr. Res. Pract. 5, 107–111. Kim, H.S., Patel, K., Muldoon-Jacobs, K., Bisht, K.S., Aykin-Burns, N., Pennington, J.D., van der Meer, R., Nguyen, P., Savage, J., Owens, K.M., Vassilopoulos, A., Ozden, O., Park, S.H., Singh, K.K., Abdulkadir, S.A., Spitz, D.R., Deng, C.X., Gius, D., 2010. SIRT3 is a mitochondria-localized tumor suppressor required for maintenance of mitochondrial integrity and metabolism during stress. Cancer Cell 17, 41–52. Kim, Y.D., Park, K.G., Lee, Y.S., Kim, D.K., Nedumaran, B., Jang, W.G., Cho, W.J., Ha, J., Lee, I.K., Lee, C.H., Choi, H.S., 2008. Metformin inhibits hepatic gluconeogenesis through AMP-activated protein kinase-dependent regulation of the orphan nuclear receptor SHP. Diabetes 57, 306–314. Kincaid, B1, Bossy-Wetzel, E., 2013. Forever young: SIRT3 a shield against mitochondrial meltdown, aging, and neurodegeneration. Front. Aging Neurosci. 5, 48. Kirkland, J.L., Peterson, C., 2009. Healthspan, translation, and new outcomes for animal studies of aging. J. Gerontol. A. Biol. Sci. Med. Sci. 64, 209–212. Kirpichnikov, D., McFarlane, S.I., Sowers, J.R., 2002. Metformin: an update. Ann. Intern. Med. 137, 25–33. Ko, Y.H., Pedersen, P.L., Geschwind, J.F., 2001. Glucose catabolism in the rabbit VX2 tumor model for liver cancer: characterization and targeting hexokinase. Cancer Lett. 173, 83–91. Ko, Y.H., Smith, B.L., Wang, Y., Pomper, M.G., Rini, D.A., Torbenson, M.S., Hullihen, J., Pedersen, P.L., 2004. Advanced cancers: eradication in all cases using 3-bromopyruvate therapy to deplete ATP. Biochem. Biophys. Res. Commun. 324, 269–275. Ko, Y.H., Verhoeven, H.A., Lee, M.J., Corbin, D.J., Vogl, T.J., Pedersen, P.L., 2012. A translational study “case report” on the small molecule “energy blocker” 3bromopyruvate (3BP) as a potent anticancer agent: from bench side to bedside. J. Bioenerg. Biomembr. 44, 163–170. Kopchick, J.J., Kelder, B., Gosney, E.S., Berryman, D.E., 2014. Evaluation of growth hormone (GH) action in mice: discovery of GH receptor antagonists and clinical indications. Mol. Cell. Endocrinol. 386, 34–45. Kumao, T., Fujii, S., Asakawa, A., Takehara, I., Fukuhara, I., 2006. Effect of coffee drink containing mannooligosaccharides on total amount of excreted fat in healthy adults. J. Health Sci. 52, 482–485. Kume, S., Uzu, T., Kashiwagi, A., Koya, D., 2010. SIRT1, a calorie restriction mimetic, in a new therapeutic approach for type 2 diabetes mellitus and diabetic vascular complications. Endocr. Metab. Immune Disord. Drug Targets 10, 16–24. Lamming, D.W., Ye, L., Katajisto, P., Goncalves, M.D., Saitoh, M., Stevens, D.M., Davis, J.G., Salmon, A.B., Richardson, A., Ahima, R.S., Guertin, D.A., Sabatini, D.M., Baur, J.A., 2012. Rapamycin-induced insulin resistance is mediated by mTORC2 loss and uncoupled from longevity. Science 335, 1638–1643. Lamming, D.W., Ye, L., Sabatini, D.M., Baur, J.A., 2013. Rapalogs and mTOR inhibitors as anti-aging therapeutics. J. Clin. Invest. 123, 980–989. Lane, M.A., Ingram, D.K., Roth, G.S., 1998. 2-Deoxy-d-glucose feeding in rats mimics physiological effects of calorie restriction. J. Anti Aging Med. 1, 327–337. LaRocca, T.J., Gioscia-Ryan, R.A., Hearon Jr., C.M., Seals, D.R., 2013. The autophagy enhancer spermidine reverses arterial aging. Mech. Ageing Dev. 134, 314–320. Lavu, S., Boss, O., Elliott, P.J., Lambert, P.D., 2008. Sirtuins—novel therapeutic targets to treat age-associated diseases. Nat. Rev. Drug Discov. 7, 841–853. Lee, J., Bruce-Keller, A.J., Kruman, Y., Chan, S.L., Mattson, M.P., 1999. 2-Deoxy-dglucose protects hippocampal neurons against excitotoxic and oxidative injury: evidence for the involvement of stress proteins. J. Neurosci. Res. 57, 48–61. Leontieva, O.V., Paszkiewicz, G.M., Blagosklonny, M.V., 2014. Weekly administration of rapamycin improves survival and biomarkers in obese male mice on high-fat


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diet. Aging Cell, http://dx.doi.org/10.1111/acel.12211 (Mar 22, Epub ahead of print). Libri, V., Brown, A.P., Gambarota, G., Haddad, J., Shields, G.S., Dawes, H., Pinato, D.J., Hoffman, E., Elliot, P.J., Vlasuk, G.P., Jacobson, E., Wilkins, M.R., Matthews, P.M., 2012. A pilot randomized, placebo controlled, double blind phase I trial of the novel SIRT1 activator SRT2104 in elderly volunteers. PLOS ONE 7 (12), e51395, http://dx.doi.org/10.1371/journal.pone.0051395 (Dec 20, Epub). Liu, D., Pitta, M., Jiang, H., Lee, J.H., Zhang, G., Chen, X., Kawamoto, E.M., Mattson, M.P., 2013. Nicotinamide forestalls pathology and cognitive decline in Alzheimer mice: evidence for improved neuronal bioenergetics and autophagy procession. Neurobiol. Aging 34, 1564–1580. Longo, V.D., Fontana, L., 2010. Calorie restriction and cancer prevention: metabolic and molecular mechanisms. Trends Pharmacol. Sci. 31, 89–98. Lyon, M.R., Reichert, R.G., 2010. The effect of a novel viscous polysaccharide along with lifestyle changes on short-term weight loss and associated risk factors in overweight and obese adults: an observational retrospective clinical program analysis. Altern. Med. Rev. 15, 68–75. Madiraju, A.K., Erion, D.M., Rahimi, Y., Zhang, X.M., Braddock, D.T., Albright, R.A., Prigaro, B.J., Wood, J.L., Bhanot, S., MacDonald, M.J., Jurczak, M.J., Camporez, J.P., Lee, H.Y., Cline, G.W., Samuel, V.T., Kibbey, R.G., Shulman, G.I., 2014. Metformin suppresses gluconeogenesis by inhibiting mitochondrial glycerophosphate dehydrogenase. Nature 510, 542–546. Madsbad, S., Dirksen, C., Holst, J.J., 2014. Mechanisms of changes in glucose metabolism and bodyweight after bariatric surgery. Lancet Diabetes Endocrinol. 2, 152–164. Majumder, S., Caccamo, A., Medina, D.X., Benavides, A.D., Javors, M.A., Kraig, E., Strong, R., Richardson, A., Oddo, S., 2012. Lifelong rapamycin administration ameliorates age-dependent cognitive deficits by reducing IL-1␤ and enhancing NMDA signaling. Aging Cell 11, 326–335. Mamczarz, J., Duffy, K., Bowker, J., Zhu, M., Hagepanos, A., Ingram, D., 2005. Enhancement of amphetamine-induced locomotor response in rats on different regimens of diet restriction and 2-deoxyglucose treatment. Neuroscience 131, 451–461. Martin-Montalvo, A., Mercken, E.M., Mitchell, S.J., Palacios, H.H., Mote, P.L., ScheibyeKnudsen, M., Gomes, A.P., Ward, T.M., Minor, R.K., Blouin, M.J., Schwab, M., Pollak, M., Zhang, Y., Yu, Y., Becker, K.G., Bohr, V.A., Ingram, D.K., Sinclair, D.A., Wolf, N.S., Spindler, S.R., Bernier, M., de Cabo, R., 2013. Metformin improves healthspan and lifespan in mice. Nat. Commun. 4, 2192. Masoro, E.J., 2005. Overview of caloric restriction and ageing. Mech. Ageing Dev. 126, 913–922. Mattison, J.A., Roth, G.S., Beasley, T.M., Tilmont, E.M., Handy, A.M., Herbert, R.L., Longo, D.L., Allison, D.B., Young, J.E., Bryant, M., Barnard, D., Ward, W.F., Qi, W., Ingram, D.K., de Cabo, R., 2012. Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study. Nature 489, 318–321. Mattison, J.A., Wang, M., Bernier, M., Zhang, J., Park, S.S., Maudsley, S., An, S.S., Santhanam, L., Martin, B., Faulkner, S., Morrell, C., Baur, J.A., Peshkin, L., Sosnowska, D., Csiszar, A., Herbert, R.L., Tilmont, E.M., Ungvari, Z., Pearson, K.J., Lakatta, E.G., de Cabo, R., 2014. Resveratrol prevents high fat/sucrose diet-induced central arterial wall inflammation and stiffening in nonhuman primates. Cell Metab. 20, 183–190. Mattson, M., 2008. Dietary factors, hormesis health. Ageing Res. Rev. 7, 43–48. Mendelsohn, A.R., Larrick, J.W., 2012. Fibroblast growth factor-21 is a promising dietary restriction mimetic. Rejuv. Res. 15, 624–628. Mercken, E.M., Carboneau, B.A., Krzysik-Walker, S.M., de Cabo, R., 2012. Of mice and men: the benefits of caloric restriction, exercise, and mimetics. Ageing Res. Rev. 11, 390–398. Mercken, E.M., Mitchell, S.J., Martin-Montalvo, A., Minor, R.K., Almeida, M., Gomes, A.P., Scheibye-Knudsen, M., Palacios, H.H., Licata, J.J., Zhang, Y., Becker, K.G., Khraiwesh, H., González-Reyes, J.A., Villalba, J.M., Baur, J.A., Elliott, P., Westphal, C., Vlasuk, G.P., Ellis, J.L., Sinclair, D.A., Bernier, M., de Cabo, R., 2014. SRT2104 extends survival of male mice on a standard diet and preserves bone and muscle mass. Aging Cell 13, 787–796. Mhurchu, C.N., Dunshea-Mooij, C., Bennett, D., Rodgers, A., 2005. Effect of chitosan on weight loss in overweight and obese individuals: a systematic review of randomized controlled trials. Obes. Rev. 6, 35–42. Miller, R.A., Harrison, D.E., Astle, C.M., Baur, J.A., Boyd, A.R., de Cabo, R., Fernandez, E., Flurkey, K., Javors, M.A., Nelson, J.F., Orihuela, C.J., Pletcher, S., Sharp, Z.D., Sinclair, D., Starnes, J.W., Wilkinson, J.E., Nadon, N.L., Strong, R., 2011. Rapamycin, but not resveratrol or simvastatin, extends life span of genetically heterogeneous mice. J. Gerontol. A. Biol. Sci. Med. Sci. 66, 191–201. Miller, R.A., Harrison, D.E., Astle, C.M., Fernandez, E., Flurkey, K., Han, M., Javors, M.A., Li, X., Nadon, N.L., Nelson, J.F., Pletcher, S., Salmon, A.B., Sharp, Z.D., Van Roekel, S., Winkleman, L., Strong, R., 2013. Rapamycin-mediated lifespan increase in mice is dose and sex dependent and metabolically distinct from dietary restriction. Aging Cell (December), http://dx.doi.org/10.1111/acel.12194. Miller, R.A., Harrison, D.E., Astle, C.M., Floyd, R.A., Flurkey, K., Hensley, K.L., Javors, M.A., Leeuwenburgh, C., Nelson, J.F., Ongini, E., Nadon, N.L., Warner, H.R., Strong, R., 2007. An Aging Interventions Testing Program: study design and interim report. Aging Cell 6, 565–575. Milman, S., Atzmon, G., Huffman, D.M., Wan, J., Crandall, J.P., Cohen, P., Barzilai, N., 2014. Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity. Aging Cell, http://dx.doi.org/10.1111/acel.12213 (Mar 12, Epub ahead of print). Milne, J.C., Lambert, P.D., Schenk, S., Carney, D.P., Smith, J.J., Gagne, D.J., Jin, L., Boss, O., Perni, R.B., Vu, C.B., Bemis, J.E., Xie, R., Disch, J.S., Ng, P.Y., Nunes, J.J., Lynch, A.V., Yang, H., Galonek, H., Israelian, K., Choy, W., Iffland, A., Lavu, S., Medvedik,

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O., Sinclair, D.A., Olefsky, J.M., Jirousek, M.R., Elliott, P.J., Westphal, C.H., 2007. Small molecule activators of SIRT1 as therapeutics for the treatment of type 2 diabetes. Nature 450, 712–716. Minois, N., 2014. Molecular basis of the ‘anti-aging’ effect of spermidine and other natural polyamines – a mini-review. Gerontology (Jan 28, Epub ahead of print). Minois, N., Carmona-Gutierrez, D., Madeo, F., 2011. Polyamines in aging and disease. Aging (Albany NY) 8, 716–732. Minor, R.K., Baur, J.A., Gomes, A.P., Ward, T.M., Csiszar, A., Mercken, E.M., Abdelmohsen, K., Shin, Y.K., Canto, C., Scheibye-Knudsen, M., Krawczyk, M., Irusta, P.M., Martín-Montalvo, A., Hubbard, B.P., Zhang, Y., Lehrmann, E., White, A.A., Price, N.L., Swindell, W.R., Pearson, K.J., Becker, K.G., Bohr, V.A., Gorospe, M., Egan, J.M., Talan, M.I., Auwerx, J., Westphal, C.H., Ellis, J.L., Ungvari, Z., Vlasuk, G.P., Elliott, P.J., Sinclair, D.A., de Cabo, R., 2011. SRT1720 improves survival and healthspan of obese mice. Sci. Rep. 1, 70. Minor, R.K., Smith Jr., D.L., Sossong, A.M., Kaushik, S., Poosala, S., Spangler, E.L., Roth, G.S., Lane, M., Allison, D.B., de Cabo, R., Ingram, D.K., Mattison, J.A., 2010. Chronic ingestion of 2-deoxy-d-glucose induces cardiac vacuolization and increases mortality in rats. Toxicol. Appl. Pharmacol. 243, 332–339. Miras, A.D., le Roux, C.W., 2014. Can medical therapy mimic the clinical efficacy or physiological effects of bariatric surgery? Int. J. Obes. (Lond.) 38, 325–333. Mitchell, S.J., Martin-Montalvo, A., Mercken, E.M., Palacios, H.H., Ward, T.M., Abulwerdi, G., Minor, R.K., Vlasuk, G.P., Ellis, J.L., Sinclair, D.A., Dawson, J., Allison, D.B., Zhang, Y., Becker, K.G., Bernier, M., de Cabo, R., 2014. The SIRT1 activator SRT1720 extends lifespan and improves health of mice fed a standard diet. Cell Rep. 6, 836–843. Miyamura, M., Schnell, O., Yamashita, C., Yoshioka, T., Matsumoto, C., Mori, T., Ukimura, A., Kitaura, Y., Matsumura, Y., Ishizaka, N., Hayashi, T., 2010. Effects of acarbose on the acceleration of postprandial hyperglycemia-induced pathological changes induced by intermittent hypoxia in lean mice. J. Pharm. Sci. 114, 32–40. Moore, D.J., Yaser, A., Connock, M.J., Bayliss, S., 2009. Clinical effectiveness and costeffectiveness of pegvisomant for the treatment of acromegaly: a systematic review and economic evaluation. BMC Endocr. Disord. 9, 20. ˜ G., Bennetzen, M.V., Eisenberg, T., Megalou, E., Schroeder, S., Morselli, E., Marino, Cabrera, S., Bénit, P., Rustin, P., Criollo, A., Kepp, O., Galluzzi, L., Shen, S., Malik, S.A., Maiuri, M.C., Horio, Y., López-Otín, C., Andersen, J.S., Tavernarakis, N., Madeo, F., Kroemer, G., 2011. Spermidine and resveratrol induce autophagy by distinct pathways converging on the acetylproteome. J. Cell Biol. 192, 615–629. Mouchiroud, L., Houtkooper, R.H., Auwerx, J., 2013. NAD+ metabolism: a therapeutic target for age-related metabolic disease. Crit. Rev. Biochem. Mol. Biol. 48, 397–408. Nadon, N.L., Strong, R., Miller, R.A., Nelson, J., Javors, M., Sharp, Z.D., Peralba, J.M., Harrison, D.E., 2008. Design of aging intervention studies: the NIA interventions testing program. Age 30, 187–199. Neff, F., Flores-Dominguez, D., Ryan, D.P., Horsch, M., Schröder, S., Adler, T., Afonso, L.C., Aguilar-Pimentel, J.A., Becker, L., Garrett, L., Hans, W., Hettich, M.M., Holtmeier, R., Hölter, S.M., Moreth, K., Prehn, C., Puk, O., Rácz, I., Rathkolb, B., Rozman, J., Naton, B., Ordemann, R., Adamski, J., Beckers, J., Bekeredjian, R., Busch, D.H., Ehninger, G., Graw, J., Höfler, H., Klingenspor, M., Klopstock, T., Ollert, M., Stypmann, J., Wolf, E., Wurst, W., Zimmer, A., Fuchs, H., Gailus-Durner, V., Hrabe de Angelis, M., Ehninger, D., 2013. Rapamycin extends murine lifespan but has limited effects on aging. J. Clin. Invest. 123, 3272–3291. Nishimura, K., Shiina, R., Kashiwagi, K., Igarashi, K., 2006. Decrease in polyamines with aging and their ingestion from food and drink. J. Biochem. 139, 81–90. Omodei, D., Fontana, L., 2011. Calorie restriction and prevention of age-associated chronic disease. FEBS Lett. 585, 1537–1542. Onken, B., Driscoll, M., 2010. Metformin induces a dietary restriction-like state and the oxidative stress response to extend C. elegans healthspan via AMPK, LKB1, and SKN-1. PLoS ONE 5, e8758. Onyango, P., Celic, I., McCaffery, J.M., Boeke, J.D., Feinberg, A.P., 2002. SIRT3, a human SIR2 homologue, is an NAD-dependent deacetylase localized to mitochondria. Proc. Natl. Acad. Sci. U. S. A. 99, 13653–13658. Ozcelik, S., Fraser, G., Castets, P., Schaeffer, V., Skachokova, Z., Breu, K., Clavaguera, F., Sinnreich, M., Kappos, L., Goedert, M., Tolnay, M., Winkler, D.T., 2013. Rapamycin attenuates the progression of tau pathology in P301S tau transgenic mice. PLOS ONE 8 (5), e62459. Pacholec, M., Bleasdale, J.E., Chrunyk, B., Cunningham, D., Flynn, D., Garofalo, R.S., Griffith, D., Griffor, M., Loulakis, P., Pabst, B., Qiu, X., Stockman, B., Thanabal, V., Varghese, A., Ward, J., Withka, J., Ahn, K., 2010. SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1. J. Biol. Chem. 285, 8340–8351. Padwal, R., Li, S.K., Lau, D.C., 2003. Long-term pharmacotherapy for overweight and obesity: a systematic review and meta-analysis of randomized controlled trials. Int. J. Obes. Relat. Metab. Disord. 27, 1437–1446. Papanas, N., Maltezos, E., 2009. Oral antidiabetic agents: anti-atherosclerotic properties beyond glucose lowering? Curr. Pharm. Des. 15, 3179–3192. Park, S.H., Ozden, O., Jiang, H., Cha, Y.I., Pennington, J.D., Aykin-Burns, N., Spitz, D.R., Gius, D., Kim, H.S., 2011. Sirt3, mitochondrial ROS, ageing, and carcinogenesis. Int. J. Mol. Sci. 12, 6226–6239. Park, S.J., Ahmad, F., Philp, A., Baar, K., Williams, T., Luo, H., Ke, H., Rehmann, H., Taussig, R., Brown, A.L., Kim, M.K., Beaven, M.A., Burgin, A.B., Manganiello, V., Chung, J.H., 2012. Resveratrol ameliorates aging-related metabolic phenotypes by inhibiting cAMP phosphodiesterases. Cell 148, 421–433. Parker, J.C., 2001. Glucose-6-phosphate translocase as a target for the design of antidiabetic agents. Drugs Future 26, 687. Pearson, K.J., Baur, J.A., Lewis, K.N., Peshkin, L., Price, N.L., Labinskyy, N., Swindell, W.R., Kamara, D., Minor, R.K., Perez, E., Jamieson, H.A., Zhang, Y., Dunn, S.R.,


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Sharma, K., Pleshko, N., Woollett, L.A., Csiszar, A., Ikeno, Y., Le Couteur, D., Elliott, P.J., Becker, K.G., Navas, P., Ingram, D.K., Wolf, N.S., Ungvari, Z., Sinclair, D.A., de Cabo, R., 2008. Resveratrol delays age-related deterioration and mimics transcriptional aspects of dietary restriction without extending life span. Cell Metab. 8, 157–168. Pedersen, P.L., 2007. Warburg, me and hexokinase 2: multiple discoveries of key molecular events underlying one of cancers’ most common phenotypes, the “Warburg Effect”, i.e., elevated glycolysis in the presence of oxygen. J. Bioenerg. Biomembr. 39, 211–219. Pilmore, H.L., 2010. Metformin: potential benefits and use in chronic kidney disease. Nephrology 15, 412–418. Pucciarelli, S., Moreschini, B., Micozzi, D., De Fronzo, G.S., Carpi, F.M., Polzonetti, V., Vincenzetti, S., Mignini, F., Napolioni, V., 2012. Spermidine and spermine are enriched in whole blood of nona/centenarians. Rejuv. Res. 15, 590–595. Ramirez, R., Rasschaert, J., Laghmich, A., Louchami, K., Nadi, A.B., Jijakli, H., Kadiata, M.M., Sener, A., Malaisse, W.J., 2001. Uptake of d-mannoheptulose by normal and tumoral pancreatic islet cells. Int. J. Mol. Med. 7, 631–638. Rasschaert, J., Kadiata, M.M., Malaisse, W.J., 2001. Effects of d-mannoheptulose upon d-glucose metabolism in tumoral pancreatic islet cells. Mol. Cell. Biochem. 226, 77–81. Rattan, S.I.S., 2008. Hormesis in aging. Ageing Res. Rev. 7, 63–78. Reimer, R.A., Grover, G.J., Koetzner, L., Gahler, R.J., Lyon, M.R., Wood, S., 2011. The soluble fiber complex PolyGlycopleX lowers serum triglycerides and reduces hepatic steatosis in high-sucrose-fed rats. Nutr. Res. 31, 296–301. Ribaric, G., Buchwald, J.N., McGlennon, T.W., 2014. Diabetes and weight in comparative studies of bariatric surgery vs. conventional medical therapy: a systematic review and meta-analysis. Obes. Surg. 24, 437–455. Ricci, C., Gaeta, M., Rausa, E., Macchitella, Y., Bonavina, L., 2014. Early impact of bariatric surgery on type II diabetes, hypertension, and hyperlipidemia: a systematic review, meta-analysis and meta-regression on 6,587 patients. Obes. Surg. 24, 522–528. Richardson, A., 2013. Rapamycin, anti-aging, and avoiding the fate of Tithonus. J. Clin. Invest. 123, 3204–3206. Roth, G., Hayek, M., Massimino, S., Davenport, G., Arking, R., Bartke, A., Bonkowski, M., Ingram, D., 2009. Mannoheptulose: glycolytic inhibitor and novel caloric restriction mimetic. Exp. Biol. (Abstract 553.1). Roth, G.S., Lane, M.A., Ingram, D.K., 2005. Caloric restriction mimetics: the next phase. Ann. N.Y. Acad. Sci. 1057, 365–371. Roth, G.S., Lane, M.A., Ingram, D.K., Mattison, J., Elahi, D., Tobin, J., Muller, D., Metter, E.J., 2002. Biomarkers of caloric restriction may predict longevity in humans. Science 297, 881. Rucker, D., Padwal, R., Li, S.K., Curioni, C., Lau, D.C., 2007. Long term pharmacotherapy for obesity and overweight: updated meta-analysis. BMJ 335, 1194–1199. Sakata, Y., Zhuang, H., Kwansa, H., Koehler, R.C., Doré, S., 2010. Resveratrol protects against experimental stroke: putative neuroprotective role of heme oxygenase 1. Exp. Neurol. 224, 325–329. Salminen, A., Kaarniranta, K., 2009. Regulation of the aging process by autophagy. Trends Mol. Med. 15, 217–224. Sarbassov, D., Ali, S., Kim, D., Guertin, D., Latek, R., Erdjument-Bromage, H., Tempst, P., Sabatini, D., 2004. Rictor, a novel binding partner of mTOR, defines a rapamycininsensitive and raptor-independent pathway that regulates the cytoskeleton. Curr. Biol. 14, 1296–1302. Scarpello, J.H., 2003. Improving survival with metformin: the evidence base today. Diabetes Metab. 29, 6S36–6S43. Schmeisser, K., Mansfeld, J., Kuhlow, D., Weimer, S., Priebe, S., Heiland, I., Birringer, M., Groth, M., Segref, A., Kanfi, Y., Price, N.L., Schmeisser, S., Schuster, S., Pfeiffer, A.F., Guthke, R., Platzer, M., Hoppe, T., Cohen, H.Y., Zarse, K., Sinclair, D.A., Ristow, M., 2013. Role of sirtuins in lifespan regulation is linked to methylation of nicotinamide. Nat. Chem. Biol. 9, 693–700. Schmidt, C., 2010. GSK/Sirtris compounds dogged by assay artifacts. Nat. Biotechnol. 28, 185–186. Schulz, T.J., Zarse, K., Voigt, A., Urban, N., Birringer, M., Ristow, M., 2007. Glucose restriction extends Caenorhabditis elegans life span by inducing mitochondrial respiration and increasing oxidative stress. Cell Metab. 6, 280–293. Selman, C., 2014. Dietary restriction and the pursuit of effective mimetics. Proc. Nutr. Soc. (January), 1–11. Seyfried, F., le Roux, C.W., Bueter, M., 2011. Lessons learned from gastric bypass operations in rats. Obes. Facts 4 (Suppl. 1), 3–12. Sharma, A.M., Golay, A., 2002. Effect of orlistat-induced weight loss on blood pressure and heart rate in obese patients with hypertension. J. Hypertens. 20, 1873–1878. Siebenhofer, A., Horvath, K., Jeitler, K., Berghold, A., Stich, A.K., Matyas, E., Pignitter, N., Siering, U., 2009. Long-term effects of weight-reducing drugs in hypertensive patients. Cochrane Database Syst. Rev. 3 (July), CD007654. Sigrist, S.J., Carmona-Gutierrez, D., Gupta, V.K., Bhukel, A., Mertel, S., Eisenberg, T., Madeo, F., 2014. Spermidine-triggered autophagy ameliorates memory during aging. Autophagy 10, 178–179. Sinclair, D.A., Guarente, L., 2006. Unlocking the secrets of longevity genes. Sci. Am. 294, 48–57. Slack C1, Foley, A., Partridge, L., 2012. Activation of AMPK by the putative dietary restriction mimetic metformin is insufficient to extend lifespan in Drosophila. PLOS ONE 7 (10), e47699, http://dx.doi.org/10.1371/journal.pone.0047699. Smith, D.L., Nagy, T.R., Wilson, L.S., Barnes, S., Dong, S., Allison, D.B., 2010. The effect of mannan oligosaccharide supplementation on body weight gain and fat accrual in C57Bl/6J mice. Obesity 18, 995–999. Smith, J.J., Kenney, R.D., Gagne, D.J., Frushour, B.P., Ladd, W., Galonek, H.L., Israelian, K., Song, J., Razvadauskaite, G., Lynch, A.V., Carney, D.P., Johnson, R.J., Lavu, S.,

Iffland, A., Elliott, P.J., Lambert, P.D., Elliston, K.O., Jirousek, M.R., Milne, J.C., Boss, O., 2009. Small molecule activators of SIRT1 replicate signaling pathways triggered by calorie restriction in vivo. BMC Syst. Biol. 10, 31. Soda, K., Dobashi, Y., Kano, Y., Tsujinaka, S., Konishi, F., 2009. Polyamine-rich food decreases age-associated pathology and mortality in aged mice. Exp. Gerontol. 44, 727–732. Solah, V.A., Brand-Miller, J.C., Atkinson, F.S., Gahler, R.J., Kacinik, V., Lyon, M.R., Wood, S., 2014. Dose–response effect of a novel functional fibre, PolyGlycopleX® , PGX® , on satiety. Appetite 77C, 74–78. Someya, S., Yu, W., Hallows, W.C., Xu, J., Vann, J.M., Leeuwenburgh, C., Tanokura, M., Denu, J.M., Prolla, T.A., 2010. Sirt3 mediates reduction of oxidative damage and prevention of age-related hearing loss under caloric restriction. Cell 143, 802–812. Sparks, C.A., Guertin, D.A., 2010. Targeting mTOR: prospects for mTOR complex 2 inhibitors in cancer therapy. Oncogene 29, 3733–3744. Spilman, P., Podlutskaya, N., Hart, M.J., Debnath, J., Gorostiza, O., Bredesen, D., Richardson, A., Strong, R., Galvan, V., 2010. Inhibition of mTOR by rapamycin abolishes cognitive deficits and reduces amyloid-beta levels in a mouse model of Alzheimer’s disease. PLoS ONE 5 (April (4)), e9979. Stanfel, M.N., Shamieh, L.S., Kaeberlein, M., Kennedy, B.K., 2009. The TOR pathway comes of age. Biochim. Biophys. Acta 1790, 1067–1074. Strong, R., Miller, R.A., Astle, C.M., Floyd, R.A., Flurkey, K., Hensley, K.L., Javors, M.A., Leeuwenburgh, C., Nelson, J.F., Ongini, E., Nadon, N.L., Warner, H.R., Harrison, D.E., 2008. Nordihydroguaiaretic acid and aspirin increase lifespan of genetically heterogeneous male mice. Aging Cell 7, 641–650. Strong, R., Miller, R.A., Astle, C.M., Baur, J.A., de Cabo, R., Fernandez, E., Guo, W., Javors, M., Kirkland, J.L., Nelson, J.F., Sinclair, D.A., Teter, B., Williams, D., Zaveri, N., Nadon, N.L., Harrison, D.E., 2013. Evaluation of resveratrol, green tea extract, curcumin, oxaloacetic acid, and medium-chain triglyceride oil on life span of genetically heterogeneous mice. J. Gerontol. A. Biol. Sci. Med. Sci. 68, 6–16. Takao, I., Fujii, S., Ishii, A., et al., 2006. Effects of mannooligosaccharides from coffee mannan on fat storage in mice fed a high fat diet. J. Health Sci. 52, 333– 337. Takahashi, M., Inoue, K., Yoshida, M., Morikawa, T., Shibutani, M., Nishikawa, A., 2009. Lack of chronic toxicity or carcinogenicity of dietary N-acetylglucosamine in F344 rats. Food Chem. Toxicol. 47, 462–471. Tatar, M., 2009. Can we develop genetically tractable models to assess healthspan (rather than life span) in animal models? J. Gerontol. A. Biol. Sci. Med. Sci. 64, 209–212. Tatar, M., Bartke, A., Antebi, A., 2003. The endocrine regulation of aging by insulinlike signals. Science 299, 1346–1355. Timmers, S., Konings, E., Bilet, L., Houtkooper, R.H., van de Weijer, T., Goossens, G.H., Hoeks, J., van der Krieken, S., Ryu, D., Kersten, S., Moonen-Kornips, E., Hesselink, M.K., Kunz, I., Schrauwen-Hinderling, V.B., Blaak, E.E., Auwerx, J., Schrauwen, P., 2011. Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans. Cell Metab. 14 (November (5)), 612–622. Tirupathi Pichiah, P.B., Suriyakalaa, U., Kamalakkannan, S., Kokilavani, P., Kalaiselvi, S., SankarGanesh, D., Gowri, J., Archunan, G., Cha, Y.S., Achiraman, S., 2011. Spermidine may decrease ER stress in pancreatic beta cells and may reduce apoptosis via activating AMPK dependent autophagy pathway. Med. Hypotheses 77, 677–679. Tokunaga, C., Yoshino, K., Yonezawa, K., 2004. mTOR integrates amino acid- and energy-sensing pathways. Biochem. Biophys. Res. Commun. 313, 443–446. Tzatsos, A., Kandror, K.V., 2006. Nutrients suppress phosphatidylinositol 3kinase/Akt signaling via raptor-dependent mTOR-mediated insulin receptor substrate 1 phosphorylation. Mol. Cell. Biol. 26, 63–76. Umemura, M., Fujii, S., Asano, I., Hoshino, H., Iino, H., 2004. Effect of coffee mix drink containing mannooligosaccharides from coffee mannan on defecation and fecal microbiota in healthy volunteers. Food Sci. Technol. Res. 10, 195– 198. Valenzano, D.R., Terzibasi, E., Genade, T., Cattaneo, A., Domenici, L., Cellerino, A., 2006. Resveratrol prolongs lifespan and retards the onset of age-related markers in a short-lived vertebrate. Curr. Biol. 16, 296–300. Venkatasubramanian, S., Noh, R.M., Daga, S., Langrish, J.P., Joshi, N.V., Mills, N.L., Hoffmann, E., Jacobson, E.W., Vlasuk, G.P., Waterhouse, B.R., Lang, N.N., Newby, D.E., 2013. Cardiovascular effects of a novel SIRT1 activator, SRT2104, in otherwise healthy cigarette smokers. J. Am. Heart Assoc., e000042, http://dx.doi.org/10.1161/JAHA.113.000042. Wan, R., Camandola, S., Mattson, M.P., 2003. Intermittent fasting and dietary supplementation with 2-deoxy-d-glucose improve functional and metabolic cardiovascular risk factors in rats. FASEB J. 17, 1133–1134. Wan, R., Camandola, S., Mattson, M.P., 2004. Dietary supplementation with 2-deoxyd-glucose improves cardiovascular and neuroendocrine stress adaptation in rats. Am. J. Physiol. Heart Circ. Physiol. 287, H1186–H1193. Wang, X., Beugnet, Murakami, M., Yamanaka, Proud, C.G., 2005. Distinct signaling events downstream of mTOR cooperate to mediate the effects of amino acids and insulin on initiation factor 4E-binding proteins. Mol. Cell. Biol. 25, 2558– 2572. Warburg, O., Posener, K., Negelein, E., 1930. Ueber den Stoffwechsel der Tumoren. Biochem. Z. 152, 319–344. Weimer, S., Priebs, J., Kuhlow, D., Groth, M., Priebe, S., Mansfeld, J., Merry, T.L., Dubuis, S., Laube, B., Pfeiffer, A.F., Schulz, T.J., Guthke, R., Platzer, M., Zamboni, N., Zarse, K., Ristow, M., 2014. d-Glucosamine supplementation extends life span of nematodes and of ageing mice. Nat. Commun., http://dx.doi.org/10.1038/ncomms4563.


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Weindruch, R., Keenan, K.P., Carney, J.M., Fernandes, G., Feuers, R.J., Floyd, R.A., Halter, J.B., Ramsey, J.J., Richardson, A., Roth, G.S., Spindler, S.R., 2001. Caloric restriction mimetics: metabolic interventions. J. Gerontol. A. Biol. Sci. Med. Sci. 56, 20–33. Weiss, E.P., Racette, S.B., Villareal, D.T., Fontana, L., Steger-May, K., Schechtman, K.B., Klein, S., Holloszy, J.O., Washington University School of Medicine CALERIE Group, 2006. Improvements in glucose tolerance and insulin action induced by increasing energy expenditure or decreasing energy intake: a randomized controlled trial. Am. J. Clin. Nutr. 84, 1033–1042. Wilkinson, J.E., Burmeister, L., Brooks, S.V., Chan, C.C., Friedline, S., Harrison, D.E., Hejtmancik, J.F., Nadon, N., Strong, R., Wood, L.K., Woodward, M.A., Miller, R.A., 2012. Rapamycin slows aging in mice. Aging Cell 11, 675–682. Williams, D.S., Cash, A., Hamadani, L., Diemer, T., 2009. Oxaloacetate supplementation increases lifespan in Caenorhabditis elegans through an AMPK/FOXOdependent pathway. Aging Cell 8, 765–768. Witte, A.V., Kerti, L., Margulies, D.S., Flöel, A., 2014. Effects of resveratrol on memory performance, hippocampal functional connectivity, and glucose metabolism in healthy older adults. J. Neurosci. 34, 7862–7870. Wood, J.G., Rogina, B., Lavu, S., Howitz, K., Helfand, S.L., Tatar, M., Sinclair, D., 2004. Sirtuin activators mimic caloric restriction and delay ageing in metazoans. Nature 430, 686–689. Wu, Z., Xu, Q., Zhang, L., Kong, D., Ma, R., Wang, L., 2009. Protective effect of resveratrol against kainate-induced temporal lobe epilepsy in rats. Neurochem. Res. 34, 1393–1400. Xu, R.H., Pelicano, H., Zhou, Y., Carew, J.S., Feng, L., Bhalla, K.N., Keating, M.J., Huang, P., 2005. Inhibition of glycolysis in cancer cells: a novel strategy to overcome drug resistance associated with mitochondrial respiratory defect and hypoxia. Cancer Res. 65, 13–621. Yamamoto, H.A., Mohanan, P.V., 2003. Effect of alpha-ketoglutarate and oxaloacetate on brain mitochondrial DNA damage and seizures induced by kainic acid in mice. Toxicol. Lett. 143, 115–122. Yamamoto, M., Otsuki, M., 2006. Effect of inhibition of alpha-glucosidase on agerelated glucose intolerance and pancreatic atrophy in rats. Metabolism. 55, 533–540. Yamamoto, T., Hinoi, E., Fujita, H., Iezaki, T., Takahata, Y., Takamori, M., Yoneda, Y., 2012. The natural polyamines spermidine and spermine prevent bone loss through preferential disruption of osteoclastic activation in ovariectomized mice. Br. J. Pharmacol. 166, 1084–1096. Yang, D.L., Zhang, H.G., Xu, Y.L., Gao, Y.H., Yang, X.J., Hao, X.Q., Li, X.H., 2010. Resveratrol inhibits right ventricular hypertrophy induced by monocrotaline in rats. Clin. Exp. Pharmacol. Physiol. 37, 150–155. Yang, Q., Inoki, K., Ikenoue, T., Guan, K.L., 2006. Identification of Sin1 as an essential TORC2 component required for complex formation and kinase activity. Genes Dev. 20, 2820–2832. Yang, W., Liu, J., Shan, Z., Tian, H., Zhou, Z., Ji, Q., Weng, J., Jia, W., Lu, J., Liu, J., Xu, Y., Yang, Z., Chen, W., 2014. Acarbose compared with metformin as initial therapy in patients with newly diagnosed type 2 diabetes: an open-label, non-inferiority randomised trial. Lancet Diabetes Endocrinol. 2, 46–55. Yao, J., Chen, S., Mao, Z., Cadenas, E., Brinton, R.D., 2011. 2-Deoxy-d-glucose treatment induces ketogenesis, sustains mitochondrial function, and reduces pathology in female mouse model of Alzheimer’s disease. PLoS ONE 6 (7), e21788, http://dx.doi.org/10.1371/journal.pone.0021788.

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Yip, S., Plank, L.D., Murphy, R., 2013. Gastric bypass and sleeve gastrectomy for type 2 diabetes: a systematic review and meta-analysis of outcomes. Obes. Surg. 23, 1994–2003. Yoshikawa, K., 1968. Studies on anti-diabetic effect of sodium oxaloacetate. Tohoku J. Exp. Med. 96, 127–141. Yoshino, J., Conte, C., Fontana, L., Mittendorfer, B., Imai, S., Schechtman, K.B., Gu, C., Kunz, I., Rossi Fanelli, F., Patterson, B.W., Klein, S., 2012. Resveratrol supplementation does not improve metabolic function in nonobese women with normal glucose tolerance. Cell Metab. 16, 658–664. Yousuf, S., Atif, F., Ahmad, M., Hoda, N., Ishrat, T., Khan, B., Islam, F., 2009. Resveratrol exerts its neuroprotective effect by modulating mitochondrial dysfunctions and associated cell death during cerebral ischemia. Brain Res. 1250, 242–253. Yu, Z.F., Mattson, M.P., 1999. Dietary restriction and 2-deoxyglucose administration reduce focal ischemic brain damage and improve behavioral outcome: evidence for a preconditioning mechanism. J. Neurosci. Res. 57, 830–839. Zemke, D., Azhar, S., Majid, A., 2007. The mTOR pathway as a potential target for the development of therapies against neurological disease. Drug News Perspect. 20, 495–499. Zhang, W., Kim, D., Philip, E., Miyan, Z., Barykina, I., Schmidt, B., Stein, H., 2013. The Gluco VIP study. A multinational, observational study to investigate the efficacy, safety and tolerability of acarbose as add-on or monotherapy in a range of patients: the Gluco VIP study. Clin Drug Invest. 33, 263–274. Zhang, Y., Bokov, A., Gelfond, J., Soto, V., Ikeno, Y., Hubbard, G., Diaz, V., Sloane, L., Maslin, K., Treaster, S., Réndon, S., van Remmen, H., Ward, W., Javors, M., Richardson, A., Austad, S.N., Fischer, K., 2014. Rapamycin extends life and health in C57BL/6 mice. J. Gerontol. A. Biol. Sci. Med. Sci. 69, 119–130. Zhi, J., Melia, A.T., Eggers, H., Joly, R., Patel, I.H., 1995. Review of limited systemic absorption of orlistat, a lipase inhibitor, in healthy human volunteers. J. Clin. Pharmacol. 35, 1103–1108. Zhou, Y.H., Ma, X.Q., Wu, C., Lu, J., Zhang, S.S., Guo, J., Wu, S.Q., Ye, X.F., Xu, J.F., He, J., 2012. Effect of anti-obesity drug on cardiovascular risk factors: a systematic review and meta-analysis of randomized controlled trials. PLOS ONE 7, e39062. Zhu, Q., Tong, Y., Wu, T., Li, J., Tong, N., 2013. Comparison of the hypoglycemic effect of acarbose monotherapy in patients with type 2 diabetes mellitus consuming an Eastern or Western diet: a systematic meta-analysis. Clin. Ther. 35, 880–899. Zhu, Z., Jiang, W., McGinley, J.N., Thompson, H.J., 2005. 2-Deoxyglucose as an energy restriction mimetic agent: effects on mammary carcinogenesis and on mammary tumor cell growth in vitro. Cancer Res. 65, 7023–7030. Zlotnik, A., Gruenbaum, S.E., Artru, A.A., Rozet, I., Dubilet, M., Tkachov, S., Brotfain, E., Klin, Y., Shapira, Y., Teichberg, V.I., 2009. The neuroprotective effects of oxaloacetate in closed head injury in rats is mediated by its blood glutamate scavenging activity: evidence from the use of maleate. J. Neurosurg. Anesthesiol. 21, 235–241. Zlotnik, A., Sinelnikov, I., Gruenbaum, B.F., Gruenbaum, S.E., Dubilet, M., Dubilet, E., Leibowitz, A., Ohayon, S., Regev, A., Boyko, M., Shapira, Y., Teichberg, V.I., 2012. Effect of glutamate and blood glutamate scavengers oxaloacetate and pyruvate on neurological outcome and pathohistology of the hippocampus after traumatic brain injury in rats. Anesthesiology 116, 73–83. Zou, S., Carey, J.R., Liedo, P., Ingram, D.K., Müller, H.G., Wang, J.L., Yao, F., Yu, B., Zhou, A., 2009. The prolongevity effect of resveratrol depends on dietary composition and calorie intake in a tephritid fruit fly. Exp. Gerontol. 44, 472–476.


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