Psychiatry Research ∎ (∎∎∎∎) ∎∎∎–∎∎∎
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Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment Bun-Hee Lee a,1, Jin-Pyo Hong b,1, Jung-A Hwang c, Byung-Joo Ham d, Kyoung-Sae Na e, Won-Joong Kim f,g, Jose Trigo f, Yong-Ku Kim c,d,n a
Department of Psychiatry, Seoul Metropolitan Eunpyeong Hospital, 90, Baengyeonsan-ro, Eunpyeong-gu, Seoul, 122-913, Republic of Korea Department of Psychiatry, Samsung Medical Center, 81, Irwon-ro, Gangnam-gu, Seoul, 135-710, Republic of Korea c Department of Psychiatry, Korea University Ansan Hospital, 516, Gojan-dong, Ansan, Kyunggi 425-707, Republic of Korea d Department of Psychiatry, College of Medicine, Korea University, 73, Inchon-ro, Seongbuk-gu, Seoul 136-706, Republic of Korea e Department of Psychiatry, Gacheon University Gil Medical Center, 1198, Guwol 1-dong, Namdong-gu, Incheon, Republic of Korea f Translational Addiction Research Laboratory Centre for Addicition and Mental Health (CAMH), Toronto, Ontario, Canada g McMaster University, Hamilton, Ontario, Canada b
art ic l e i nf o
a b s t r a c t
Article history: Received 3 November 2014 Received in revised form 13 February 2015 Accepted 16 April 2015
Vascular endothelial growth factor (VEGF), a potent angiogenetic factor, is a known neurotrophic factor. In this study, we examined plasma levels of VEGF in 50 patients with schizophrenia (SPR) and 50 healthy control subjects. We also explored any changes in plasma VEGF levels after 6-week treatment with antipsychotic agents in patients with schizophrenia. All subjects with schizophrenia were either medication-naïve or medication-free for at least 4 weeks before assessment. Plasma VEGF levels in all subjects were significantly correlated with smoking duration, which was considered to be a significant covariate. Pre-treatment plasma VEGF levels in patients with schizophrenia were significantly lower than those in healthy controls. Post-treatment VEGF levels were significantly increased in patients with schizophrenia. Plasma VEGF levels in patients with schizophrenia did not exhibit significant correlation with the total or subscale scores of the Positive and Negative Syndrome Scale (PANSS) either at baseline or at the end of the 6-week treatment. In conclusion, our findings reveal that plasma VEGF levels before treatment were lower in patients with schizophrenia and that their VEGF levels increased after treatment. Thus, VEGF may have a neuroprotective role in the improvement of schizophrenia or in the treatment effects of antipsychotics. & 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Vascular endothelial growth factor Schizophrenia Antipsychotic agent
1. Introduction Vascular endothelial growth factor (VEGF) is a potent angiogenetic factor that can induce vascular endothelial cell proliferation, migration, and vasopermeability in various kinds of tissues (Ferrara et al., 2003). Moreover, VEGF has been reported to be a neurotrophic factor, and is produced by various cells, including endothelial and mononuclear cells (Dvorak, 2002), and the major receptors of VEGF are expressed not only by endothelial cells, but also by astrocytes, mature neurons, and neuronal progenitors in
Abbreviations: PANSS, the Positive and Negative Syndrome Scale for schizophrenia; VEGF, vascular endothelial growth factor n Corresponding author at: Department of Psychiatry, Korea University Ansan Hospital, 516, Gojan-dong, Ansan, Kyunggi 425-707, Republic of Korea. Tel.: þ82 31 412 5140; fax: þ 82 31 412 5144. E-mail address: [email protected] (Y.-K. Kim). 1 These authors contributed equally to this work.
the adult brain, including the hippocampus (deVries et al., 1992; Krum and Rosenstein, 1998; Yang et al., 2003). VEGF plays important roles in neuronal survival, neuroprotection, regeneration, growth, differentiation, and axonal outgrowth (Sun et al., 2003). Animal studies demonstrate that adult neurogenesis occurs within an angiogenic niche in the hippocampus and in that region, VEGF stimulates the proliferation of neuronal progenitors in vitro and in vivo (Palmer et al., 2000; Jin et al., 2002). VEGF has also been observed to promote neurite outgrowth (Khaibullina et al., 2004). Accordingly, VEGF seems to be a critical factor in adult neurogenesis in the hippocampus. A recent imaging study with voxel-based morphometry reported that first-episode patients with schizophrenia have reduced volume in the bilateral hippocampus, parahippocampus, and superior and middle temporal gyri of the brain (Hu et al., 2013). In line with these findings, a postmortem study showed that the proliferation of neural stem cells was diminished in the hippocampus of patients with schizophrenia (Reif et al., 2006). Another study reported decreased VEGF
http://dx.doi.org/10.1016/j.psychres.2015.04.020 0165-1781/& 2015 Elsevier Ireland Ltd. All rights reserved.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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expression in the brain among patients with schizophrenia (Fulzele and Pillai, 2009). However, a recent clinical study found no significant difference in serum VEGF levels between patients with first-episode psychosis and healthy controls (Di Nicola et al., 2013). A possible explanation for these divergent results is that patients with first-episode psychosis in the study by Di Nicola et al. (2013) were not specifically diagnosed with schizophrenia. Indeed, clinical data are not yet available regarding VEGF levels in patients with schizophrenia. We hypothesized that VEGF might be associated with the development of or improvement in schizophrenia as a neurotrophic factor. The aim of this study was to determine whether or not there was a difference in plasma VEGF levels between patients with schizophrenia and healthy controls. We also explored alterations in plasma VEGF levels in patients with schizophrenia before and after treatment with antipsychotic agents. Additionally, we assessed whether plasma VEGF levels correlated with smoking status and duration and considered such variables to be covariants because some studies have suggested that smoking, a known contributing factor of endothelial damage, may affect plasma or serum VEGF levels (Schmidt-Lucke et al., 2005).
density of the color reaction in the wells was read using a microtiter plate reader (μQuant, Winooski, VT, USA) set to 450 nm. The intra- and inter-assay coefficients of variation were below 7%. The concentrations of the samples in each plate were calculated according to a standard curve.
2. Methods
3.1. Demographic data
2.1. Subjects
Table 1 presents demographic data for the 100 subjects in this study. There were no significant differences in age or sex between patients with schizophrenia and healthy controls. There was a trending difference in body mass index (BMI) between the two groups (t¼ 1.904, p¼ 0.060). In the entire sample, there were no significant correlations between plasma VEGF levels and sex, age, or BMI (data not shown). The distribution of smoking status did not significantly differ between patients with schizophrenia and healthy controls (χ2 ¼0.508, p¼ 0.476). Among smokers, the number of cigarettes smoked per day and duration of smoking did not differ between patients with schizophrenia and healthy controls (t¼0.128, d.f.¼21, p¼0.900, t¼ 0.119, d. f.¼21, p¼0.907, respectively). Across all subjects, mean plasma VEGF level (85.09776.14 pg/mL) in smokers was higher than that in
This study included 50 patients with schizophrenia hospitalized in the Department of Psychiatry, Ansan Hospital, College of Medicine, Korea University, Kyunggi, Korea. All patients were interviewed by a trained psychiatrist using the Structured Clinical Interview for DSM-IV (SCID) (First et al., 1998). Patients were either medication-naïve or medication-free for at least 4 weeks prior to assessment. Patients (22 males and 28 females; mean age7 S.D.¼ 33.17 8.9 years) were diagnosed with schizophrenia according to DSM-IV criteria. We excluded patients with any past history of Axis I psychiatric disorders other than schizophrenia, such as mood disorders and alcohol and/or substance dependence. We also excluded patients with a past history of chronic adverse events, such as tardive dyskinesia, or with a personal history of medical illness including diabetes mellitus or hypertension, as well as patients who were pregnant or lactating. Patients with schizophrenia were treated with risperidone (n ¼24), amisulpride (n¼ 14), aripiprazole (n¼7), quetiapine (n¼3), or olanzapine (n¼ 2), at a flexible dosage based on their psychiatric symptoms. The group of 50 healthy controls (24 males and 26 females; mean age7S. D.¼ 32.777.2 years) consisted of randomly selected healthy volunteers who participated in this study at the Korea University Ansan Hospital. Healthy controls were evaluated using the SCID. Controls had no personal or familial psychiatric or medical history. All subjects were free of chronic and acute physical illnesses within 4 weeks prior to enrollment. All controls had normal laboratory findings on blood chemistry, renal function, thyroid function, liver function, and on an electrocardiography. The study protocol was approved by the Ethics Committee of Korea University. Written informed consent was obtained from each subject. 2.2. Assessment 2.2.1. Clinical evaluation A trained psychiatrist assessed the psychopathological status of patients using the Positive and Negative Syndrome Scale (PANSS) (Kay et al., 1987). Assessment occurred for all patients with schizophrenia at baseline and at the end of 6 weeks of treatment. Total scores and subscores for positive, negative, and general symptoms were collected. In addition, PANSS cognitive factor subscore was assessed. One proposed model of the cognitive factor of schizophrenia includes three PANSS items: ‘conceptual disorganization’ (P2), ‘difficulty in abstract thinking’ (N5), and ‘poor attention’ (G11) (Wallwork et al., 2012; Rodriguez-Jimenez et al., 2013). To evaluate the responsiveness of patients to the treatment, response was defined as demonstration of at least 30% improvement in PANSS total scores at endpoint compared to baseline (Hermes et al., 2012). 2.2.2. Plasma VEGF measurement For all patients and healthy controls, blood samples were drawn from the antecubital veins of subjects between 7 and 8 a.m. following an overnight fast. Approximately 10 ml of blood was collected and placed in lithium heparin vacuum tubes. VEGF levels were assayed using the sandwich ELISA method (R&D Systems, Minneapolis, MN, USA) following the manufacturer's instructions. The optical
2.3. Statistical analysis Plasma VEGF levels showed a normal distribution using the Kolmogorov– Smirnov test (Kolmogorov–Smirnov Z¼1.153, p ¼0.140). Study groups were compared on continuous variables using two-tailed t-tests, analyses of variance (ANOVA), and Kruskal–Wallis tests. For discrete variables, study groups were compared using a chi-square test. When the sample sizes of groups, for example, subject groups receiving different antipsychotic agents, were small and uneven, a non-parametric approach was used. General linear modeling was used while controlling for covariates. Differences in the patient group by medication type were also analyzed. Bonferroni corrections were used to control for multiple testing. Pearson's correlation coefficients were calculated to examine the relationships between plasma VEGF levels and clinical variables. Pre-treatment and posttreatment VEGF levels and PANSS scores of patients with schizophrenia were compared using paired t-tests. Data are presented as mean 7 S.D. The null hypothesis was rejected at po 0.05. The statistical package used for analysis was SPSS 12.0.
3. Results
Table 1 Demographic data and clinical characteristics of study subjects. Schizophrenia (n¼ 50)
Healthy controls (n¼50)
Gender (male/female)
22/28
24/26
Age (years)
33.17 8.9
32.7 7 7.2
2
BMI (kg/m )
21.8 7 2.8
23.1 73.9
Smoker (%)
13(26%)
10(20%)
χ2 ¼ 0.161, p ¼ 0.841 t ¼ 0.272, p ¼ 0.786 t ¼1.904, p ¼ 0.060 χ2 ¼ 0.508, p ¼ 0.476
Medication status when entering the study Medication-naive 31 Medication-free 19 PANSS at baseline Total score 98.2 717.5 Positive symptom 27.9 76.9 Negative symptom 20.9 76.3 General symptom 49.47 9.2 Cognitive factor 8.5 72.9 PANSS after 6-week treatment Total score 57.1 7 13.2 Positive symptom 14.2 7 4.2 Negative symptom 13.4 7 4.7 General symptom 29.5 76.9 Cognitive factor 4.7 71.5 BMI: body mass index. PANSS: the Positive and Negative Syndrome Scale for schizophrenia.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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(63.31749.42 pg/mL) in non-smokers, but this was not statistically significant (t¼ 1.622, d.f.¼ 98, p¼ 0.108). VEGF levels did not significantly correlate with the number of cigarettes smoked per day (r¼0.160, p¼ 0.112). However, there was a significant correlation between VEGF level and duration of smoking (r¼0.259, p¼0.012).
were significantly increased compared to baseline (46.93748.02 pg/mL) (t¼ 2.091, d.f.¼30, p¼ 0.049). Plasma VEGF did not correlate with PANSS total or subscale scores, or with chlorpromazine-equivalent doses (p40.05).
3.2. Plasma VEGF
4. Discussion
There was a difference in baseline plasma VEGF levels between patients with schizophrenia (47.25 747.12 pg/mL) and healthy controls (89.38 758.62 pg/mL), (t ¼3.961, d.f. ¼98, p o0.01). When controlling for BMI (p ¼0.381) and duration of smoking (p ¼0.002) as covariates, VEGF levels in patients with schizophrenia were still lower than those in healthy controls (F (1, 96) ¼3.949, p o0.01). Mean plasma VEGF level at the end of the 6-week treatment period was 138.947175.07 pg/mL in patients. There was a significant alteration in plasma VEGF levels between baseline and at the end of the 6-week treatment period in patients with schizophrenia (t¼ 3.003, d.f.¼49, p¼0.005).
In this study we found that plasma VEGF levels at baseline were significantly lower in patients with schizophrenia who were either medication-naïve or medication-free compared to healthy control subjects. In addition, we observed an increase in plasma VEGF levels after 6 weeks of medication treatment in patients with schizophrenia. To our knowledge, this is the first study to examine changes in plasma VEGF levels in patients with schizophrenia before and after treatment. One recent clinical study examined serum VEGF levels in medicationnaïve, first-episode psychosis patients aged 15–25 years before and after a 12-week treatment with quetiapine (Murphy et al., 2014). They found no significant difference in serum VEGF levels between such patients and healthy controls and no significant treatment changes in VEGF levels. An increase in serum VEGF was also reported to be positively correlated with a reduction in positive symptoms. However, our results indicate a significant increase in plasma VEGF levels after 6 weeks of treatment in patients with schizophrenia, which did not correlate with changes in PANSS scores. Previous postmortem studies found reduced VEGF activity in the brain among patients with schizophrenia. One study examining mRNA levels of VEGF in the dorsolateral prefrontal cortex area in 16 patients with schizophrenia and 18 control subjects found a significant reduction in VEGF mRNA expression in the dorsolateral prefrontal cortex of patients with schizophrenia (Fulzele and Pillai, 2009). Additionally, another postmortem study observed a significant decrease in VEGF receptor-2 levels in the prefrontal cortex of 10 patients with schizophrenia (Howell et al., 2011). VEGF seems to play a critical role in adult neurogenesis (Palmer et al., 2000). In fact, proliferation of neural stem cells in the hippocampus, the first step of adult neurogenesis, seems to be significantly reduced in patients with schizophrenia in comparison to healthy controls (Reif et al., 2006). Although most patients with schizophrenia in postmortem studies received antipsychotic medications, such findings suggest a decrease in central VEGF activity and adult neurogenesis in schizophrenia. Animal studies suggest that treatment with antipsychotic agents affects the activation of VEGF and neurogenesis. One study found that a 14-day administration of haloperidol and olanzapine increased levels of VEGF and angiogenesis in the hippocampus of rats (Pillai and Mahadik, 2006). Furthermore, 45-day treatment with olanzapine without haloperidol also enhanced VEGF levels in rats (Pillai and Mahadik, 2006). Olanzapine reportedly increases cell proliferation in the periventricular zone and prefrontal cortex of rats (Green et al., 2006). Other studies examined whether chronic administration of haloperidol and risperidone have any effect on cell genesis and cell survival in the hippocampus of adult rats treated with ketamine and saline (Keilhoff et al., 2010), finding that both haloperidol and risperidone reduce ketamine-induced cell death and enhance cell proliferation in the dentate gyrus of both ketamine- and saline-treated rats. These effects of risperidone and (to a lesser extent) haloperidol seem to be associated with the activation of VEGF. These findings are consistent with our observation that plasma VEGF levels in patients with schizophrenia increased after 6 weeks of treatment with atypical antipsychotics. However, we did not find any relationship between the increase of plasma VEGF levels and decrease in PANSS cognitive factor, positive, negative symptom subscales in patients with schizophrenia. Our study showed that patients with schizophrenia have lower plasma VEGF levels than controls before treatment and that plasma VEGF levels in patients increase after 6 weeks of treatment with
3.3. Symptoms and plasma VEGF In patients with schizophrenia patients, the mean total PANSS scores were 98.2 717.5 at baseline and 57.1 713.2 at the end of the 6-week treatment period (t¼ 11.014, d.f. ¼49, p o0.001). Subscores for positive, negative, and general symptoms and subscores for the cognitive factor significantly improved from baseline to the end of treatment (p o0.01). Among all patients, 35 (70%) were responders and 15 (30%) were non-responders. There were no differences in change in mean plasma VEGF levels from baseline to the end of treatment between responders and non-responders (t¼1.729, d.f. ¼48, p ¼0.094, t ¼0.995, d.f. ¼ 48, p ¼0.329, respectively). Plasma VEGF levels in patients with schizophrenia were not significantly correlated with total scores and subscores of the PANSS both at baseline and the end of treatment (p 40.05). When controlling for smoking duration, there were also no significant correlations between plasma VEGF levels or PANSS total and subscale scores. 3.4. Antipsychotic medications and plasma VEGF Differences in the patient group based on medication type were examined. There were no significant differences in plasma VEGF levels at baseline (χ2 ¼3.787, p¼ 0.436) or at the end of the 6-week treatment period (χ2 ¼6.583, p ¼0.160) between groups receiving the five different antipsychotic medications. There was no significant difference in the distribution of responders and nonresponders among the antipsychotic groups (χ2 ¼2.637, p ¼0.620). The chlorpromazine-equivalent dose did not correlate with plasma VEGF level at the end of the 6-week treatment period (r¼ 0.162, p¼0.385) or changes in VEGF levels from baseline to post-treatment (r¼ 0.176, p¼0.343). The chlorpromazine-equivalent dose also did not differ between responders (408.47200.4 mg) and non-responders (491.97231.6 mg) (t¼1.031, d.f.¼48, p¼0.311). 3.5. Plasma VEGF in medication-naïve patients Plasma VEGF levels at baseline were significantly lower in medication-naïve and medication-free patients than in healthy controls (F (2, 97)¼7.779, p¼0.001). After controlling for BMI (p¼0.402) and smoking duration (p¼0.002), VEGF levels in medication-naïve and medication-free patients were still lower than those in healthy controls (F (2, 95)¼8.181, p¼0.01). However, plasma VEGF levels after treatment did not differ among medication-naïve and medication-free patients and healthy controls (F (2, 97)¼1.784, p¼0.175). In medication-naïve patients, plasma VEGF levels (145.307209.02 pg/mL) at the end of treatment
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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atypical antipsychotics. Animal studies show that dopamine stimulation inhibits angiogenesis via decreased functions of VEGF and VEGF receptors in tumor tissues (Basu et al., 2001; Teunis et al., 2002; Asada et al., 2008). An in vitro study with non-functioning pituitary adenomas demonstrated that cabergoline, a dopamine D2 receptor (DR2) agonist, reduces VEGF secretion and cell viability, and that this inhibitory effect of cabergoline is blocked by sulpiride, a selective DR2 antagonist in DR2-expressing pituitary adenomas (Gagliano et al., 2013). Moreover, other animal studies with antipsychotics have suggested that risperidone and olanzapine increase the phosphorylation of the cAMP response element binding protein (CREB) in the hippocampus (Keilhoff et al., 2010; Réus et al., 2012), and that these antipsychotics enhance VEGF expression therein (Pillai and Mahadik, 2006; Keilhoff et al., 2010). There is experimental evidence that adult neurogenesis requires increased activation of VEGF and CREB in the brain (Lee et al., 2009; Oh et al., 2012). The above findings might explain the increase of plasma VEGF level after 6 weeks of treatment with antipsychotics in patients with schizophrenia in our study. Our findings indicated that the plasma VEGF level in smokers is higher than that in nonsmokers, but this was not statistically significant. One previous study suggested that smoking causes an acute increase in plasma VEGF in some, but not all, smokers with non-insulin-dependent diabetes mellitus (Wasada et al., 1998). Several clinical studies also reported similar plasma VEGF levels between smokers and non-smokers in healthy controls (Belgore et al., 2000; Schmidt-Lucke et al., 2005). However, our findings indicate that plasma VEGF levels were significantly correlated with smoking duration. Therefore, we controlled for smoking duration when analyzing plasma VEGF levels. There are several limitations to this study. First, we used relatively small sample sizes, particularly for comparing differences among medication type. Second, we examined only VEGF levels in plasma and the range of VEGF levels in our study was quite broad. VEGF is produced by various cell types, including endothelial cells, neutrophils, platelets, and mononuclear cells (Dvorak, 2002). It has been reported that VEGF levels tend to change in the same direction in plasma, serum, and the cerebrospinal fluid of patients with cerebral ischemia (Scheufler et al., 2003). However, the source of measured plasma VEGF in our subjects was not clear. Consequently, we were unable to determine whether changes in plasma VEGF levels reflect any changes in brain VEGF. Therefore we cannot explain the mechanism for VEGF alterations in schizophrenia. In this study we did not observe significant differences between plasma VEGF levels at baseline and at the end of the 6-week treatment period between responders and non-responders.
5. Conclusion We found that baseline plasma VEGF levels were lower in medication-naïve or medication-free schizophrenia patients compared to healthy controls and that VEGF levels were elevated in patients after treatment with antipsychotics. Although the mechanism of VEGF in the pathophysiology of schizophrenia has not yet been explained, it may be that VEGF has a neuroprotective role in the improvement of schizophrenia or in the treatment effects of antipsychotics.
Acknowledgments Funding for this study was provided by a grant from the Korea Health Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (A120051).
References Asada, M., Ebihara, S., Numachi, Y., Okazaki, T., Yamanda, S., Ikeda, K., Yasuda, H., Sora, I., Arai, H., 2008. Reduced tumor growth in a mouse model of schizophrenia, lacking the dopamine transporter. International Journal of Cancer 123, 511–518. Basu, S., Nagy, J.A., Pal, S., Vasile, E., Eckelhoefer, I.A., Bliss, V.S., Manseau, E.J., Dasgupta, P.S., Dvorak, H.F., Mukhopadhyay, D., 2001. The neurotransmitter dopamine inhibits angiogenesis induced by vascular permeability factor/ vascular endothelial growth factor. Nature Medicine 7, 569–574. Belgore, F.M., Lip, G.Y., Blann, A.D., 2000. Vascular endothelial growth factor and its receptor, Flt-1, in smokers and non-smokers. British Journal of Biomedical Science 57, 207–213. deVries, C., Escobedo, J.A., Ueno, H., Houck, K., Ferrara, N., Williams, L.T., 1992. The fms-like tyrosine kinase, a receptor for vascular endothelial growth factor. Science 255, 989–991. Di Nicola, M., Cattaneo, A., Hepgul, N., DiForti, M., Aitchison, K.J., Janiri, L., Murray, R. M., Dazzan, P., Pariante, C.M., Mondelli, V., 2013. Serum and gene expression profile of cytokines in first-episode psychosis. Brain, Behavior, and Immunity 31, 90–95. Dvorak, H.F., 2002. Vascular permeability factor/vascular endothelial growth factor: a critical cytokine in tumor angiogenesis and a potential target for diagnosis and therapy. Journal of Clinical Oncology 20, 4368–4380. Ferrara, N., Gerber, H.P., LeCouter, J., 2003. The biology of VEGF and its receptors. Natural Medicine 9, 669–676. First, M., Spitzer, R.L., Gibbon, M., William, J.B., 1998. Structured Clinical Interview for DSM-IV Axis I Disorder – Patient Edition (SCID-I/P, version 2.0). New York State Psychiatric Institute, New York. Fulzele, S., Pillai, A., 2009. Decreased VEGF mRNA expression in the dorsolateral prefrontal cortex of schizophrenia subjects. Schizophrenia Research 115, 372–373. Gagliano, T., Filieri, C., Minoia, M., Buratto, M., Tagliati, F., Ambrosio, M.R., Lapparelli, M., Zoli, M., Frank, G., degliUberti, E., Zatelli, M.C., 2013. Cabergoline reduces cell viability in non functioning pituitary adenomas by inhibiting vascular endothelial growth factor secretion. Pituitary 16, 91–100. Green, W., Patil, P., Marsden, C.A., Bennett, G.W., Wigmore, P.M., 2006. Treatment with olanzapine increases cell proliferation in the subventricular zone and prefrontal cortex. Brain Research 1070, 242–245. Hermes, E.D., Sokoloff, D., Stroup, T.S., Rosenheck, R.A., 2012. Minimum clinically important difference in the Positive and Negative Syndrome Scale with data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE). The Journal of Clinical Psychiatry 73, 526–532. Howell, K.R., Kutiyanawalla, A., Pillai, A., 2011. Long-term continuous corticosterone treatment decreases VEGF receptor-2 expression in frontal cortex. PLoS One 6, e20198. Hu, M., Li, J., Eyler, L., Guo, X., Wei, Q., Tang, J., Liu, F., He, Z., Li, L., Jin, H., Liu, Z., Wang, J., Liu, F., Chen, H., Zhao, J., 2013. Decreased left middle temporal gyrus volume in antipsychotic drug-naive, first-episode schizophrenia patients and their healthy unaffected siblings. Schizophrenia Research 144, 37–42. Jin, K., Zhu, Y., Sun, Y., Mao, X.O., Xie, L., Greenberg, D.A., 2002. Vascular endothelial growth factor (VEGF) stimulates neurogenesis in vitro and in vivo. Proceedings of the National Academy of Sciences of the United States of America 99, 11946–11950. Kay, S.R., Fiszbein, A., Opler, L.A., 1987. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13, 261–276. Keilhoff, G., Grecksch, G., Bernstein, H.G., Roskoden, T., Becker, A., 2010. Risperidone and haloperidol promote survival of stem cells in the rat hippocampus. European Archives of Psychiatry and Clinical Neuroscience 260, 151–162. Khaibullina, A.A., Rosenstein, J.M., Krum, J.M., 2004. Vascular endothelial growth factor promotes neurite maturation in primary CNS neuronal cultures. Brain research. Developmental Brain Research 148, 59–68. Krum, J.M., Rosenstein, J.M., 1998. VEGF mRNA and its receptor flt-1 are expressed in reactive astrocytes following neural grafting and tumor cell implantation in the adult CNS. Experimental Neurology 154, 57–65. Lee, J.S., Jang, D.J., Lee, N., Ko, H.G., Kim, H., Kim, Y.S., Kim, B., Son, J., Kim, S.H., Chung, H., Lee, M.Y., Kim, W.R., Sun, W., Zhuo, M., Abel, T., Kaang, B.K., Son, H., 2009. Induction of neuronal vascular endothelial growth factor expression by cAMP in the dentate gyrus of the hippocampus is required for antidepressantlike behaviors. The Journal of Neuroscience 29, 8493–8505. Murphy, B.P., Pang, T.Y., Hannan, A.J., Proffitt, T.M., McConchie, M., Kerr, M., Markulev, C., O’Donnell, C., McGorry, P.D., Berger, G.E., 2014. Vascular endothelial growth factor and brain-derived neurotrophic factor in quetiapine treated first-episode psychosis. Schizophrenia Research and Treatment 2014, 719395. Oh, D.H., Kim, B.W., Choi, M., Lee, G., Choi, J.S., Son, H., 2012. Changes in vascular endothelial growth factor (VEGF) induced by the Morris water maze task. Molecules and Cells 33, 295–300. Palmer, T.D., Willhoite, A.R., Gage, F.H., 2000. Vascular niche for adult hippocampal neurogenesis. The Journal of Comparative Neurology 425, 479–494. Pillai, A., Mahadik, S.P., 2006. Differential effects of haloperidol and olanzapine on levels of vascular endothelial growth factor and angiogenesis in rat hippocampus. Schizophrenia Research 87, 48–59. Réus, G.Z., Abelaira, H.M., Agostinho, F.R., Ribeiro, K.F., Vitto, M.F., Luciano, T.F., Souza, C.T., Quevedo, J., 2012. The administration of olanzapine and fluoxetine has synergistic effects on intracellular survival pathways in the rat brain. Journal of Psychiatric Research 46, 1029–1035.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
B.-H. Lee et al. / Psychiatry Research ∎ (∎∎∎∎) ∎∎∎–∎∎∎ Reif, A., Fritzen, S., Finger, M., Strobel, A., Lauer, M., Schmitt, A., Lesch, K.P., 2006. Neural stem cell proliferation is decreased in schizophrenia, but not in depression. Molecular Psychiatry 11, 514–522. Rodriguez-Jimenez, R., Bagney, A., Mezquita, L., Martinez-Gras, I., Sanchez-Morla, E. M., Mesa, N., Ibanez, M.I., Diez-Martin, J., Jimenez-Arriero, M.A., Lobo, A., Santos, J.L., Palomo, T., 2013. Cognition and the five-factor model of the positive and negative syndrome scale in schizophrenia. Schizophrenia Research 143, 77–83. Scheufler, K.M., Drevs, J., vanVelthoven, V., Reusch, P., Klisch, J., Augustin, H.G., Zentner, J., Marme, D., 2003. Implications of vascular endothelial growth factor, sFlt-1, and sTie-2 in plasma, serum and cerebrospinal fluid during cerebral ischemia in man. Journal of Cerebral Blood Flow and Metabolism 23, 99–110. Schmidt-Lucke, C., Belgore, F., Reinhold, D., Ansorge, S., Klein, H.U., Schmidt-Lucke, J.A., Lip, G.Y., 2005. Soluble vascular endothelial growth factor, soluble VEGF receptor Flt-1 and endothelial function in healthy smokers. International Journal of Cardiology 100, 207–212.
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Sun, Y., Jin, K., Xie, L., Childs, J., Mao, X.O., Logvinova, A., Greenberg, D.A., 2003. VEGF-induced neuroprotection, neurogenesis, and angiogenesis after focal cerebral ischemia. The Journal of Clinical Investigation 111, 1843–1851. Teunis, M.A., Kavelaars, A., Voest, E., Bakker, J.M., Ellenbroek, B.A., Cools, A.R., Heijnen, C.J., 2002. Reduced tumor growth, experimental metastasis formation, and angiogenesis in rats with a hyperreactive dopaminergic system. FASEB Journal 16, 1465–1467. Wallwork, R.S., Fortgang, R., Hashimoto, R., Weinberger, D.R., Dickinson, D., 2012. Searching for a consensus five-factor model of the Positive and Negative Syndrome Scale for schizophrenia. Schizophrenia Research 137, 246–250. Wasada, T., Kawahara, R., Katsumori, K., Naruse, M., Omori, Y., 1998. Plasma concentration of immunoreactive vascular endothelial growth factor and its relation to smoking. Metabolism: Clinical and Experimental 47, 27–30. Yang, S.Z., Zhang, L.M., Huang, Y.L., Sun, F.Y., 2003. Distribution of Flk-1 and Flt-1 receptors in neonatal and adult rat brains. The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology 274, 851–856.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment Bun-Hee Lee a,1, Jin-Pyo Hong b,1, Jung-A Hwang c, Byung-Joo Ham d, Kyoung-Sae Na e, Won-Joong Kim f,g, Jose Trigo f, Yong-Ku Kim c,d,n a
Department of Psychiatry, Seoul Metropolitan Eunpyeong Hospital, 90, Baengyeonsan-ro, Eunpyeong-gu, Seoul, 122-913, Republic of Korea Department of Psychiatry, Samsung Medical Center, 81, Irwon-ro, Gangnam-gu, Seoul, 135-710, Republic of Korea c Department of Psychiatry, Korea University Ansan Hospital, 516, Gojan-dong, Ansan, Kyunggi 425-707, Republic of Korea d Department of Psychiatry, College of Medicine, Korea University, 73, Inchon-ro, Seongbuk-gu, Seoul 136-706, Republic of Korea e Department of Psychiatry, Gacheon University Gil Medical Center, 1198, Guwol 1-dong, Namdong-gu, Incheon, Republic of Korea f Translational Addiction Research Laboratory Centre for Addicition and Mental Health (CAMH), Toronto, Ontario, Canada g McMaster University, Hamilton, Ontario, Canada b
art ic l e i nf o
a b s t r a c t
Article history: Received 3 November 2014 Received in revised form 13 February 2015 Accepted 16 April 2015
Vascular endothelial growth factor (VEGF), a potent angiogenetic factor, is a known neurotrophic factor. In this study, we examined plasma levels of VEGF in 50 patients with schizophrenia (SPR) and 50 healthy control subjects. We also explored any changes in plasma VEGF levels after 6-week treatment with antipsychotic agents in patients with schizophrenia. All subjects with schizophrenia were either medication-naïve or medication-free for at least 4 weeks before assessment. Plasma VEGF levels in all subjects were significantly correlated with smoking duration, which was considered to be a significant covariate. Pre-treatment plasma VEGF levels in patients with schizophrenia were significantly lower than those in healthy controls. Post-treatment VEGF levels were significantly increased in patients with schizophrenia. Plasma VEGF levels in patients with schizophrenia did not exhibit significant correlation with the total or subscale scores of the Positive and Negative Syndrome Scale (PANSS) either at baseline or at the end of the 6-week treatment. In conclusion, our findings reveal that plasma VEGF levels before treatment were lower in patients with schizophrenia and that their VEGF levels increased after treatment. Thus, VEGF may have a neuroprotective role in the improvement of schizophrenia or in the treatment effects of antipsychotics. & 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Vascular endothelial growth factor Schizophrenia Antipsychotic agent
1. Introduction Vascular endothelial growth factor (VEGF) is a potent angiogenetic factor that can induce vascular endothelial cell proliferation, migration, and vasopermeability in various kinds of tissues (Ferrara et al., 2003). Moreover, VEGF has been reported to be a neurotrophic factor, and is produced by various cells, including endothelial and mononuclear cells (Dvorak, 2002), and the major receptors of VEGF are expressed not only by endothelial cells, but also by astrocytes, mature neurons, and neuronal progenitors in
Abbreviations: PANSS, the Positive and Negative Syndrome Scale for schizophrenia; VEGF, vascular endothelial growth factor n Corresponding author at: Department of Psychiatry, Korea University Ansan Hospital, 516, Gojan-dong, Ansan, Kyunggi 425-707, Republic of Korea. Tel.: þ82 31 412 5140; fax: þ 82 31 412 5144. E-mail address: [email protected] (Y.-K. Kim). 1 These authors contributed equally to this work.
the adult brain, including the hippocampus (deVries et al., 1992; Krum and Rosenstein, 1998; Yang et al., 2003). VEGF plays important roles in neuronal survival, neuroprotection, regeneration, growth, differentiation, and axonal outgrowth (Sun et al., 2003). Animal studies demonstrate that adult neurogenesis occurs within an angiogenic niche in the hippocampus and in that region, VEGF stimulates the proliferation of neuronal progenitors in vitro and in vivo (Palmer et al., 2000; Jin et al., 2002). VEGF has also been observed to promote neurite outgrowth (Khaibullina et al., 2004). Accordingly, VEGF seems to be a critical factor in adult neurogenesis in the hippocampus. A recent imaging study with voxel-based morphometry reported that first-episode patients with schizophrenia have reduced volume in the bilateral hippocampus, parahippocampus, and superior and middle temporal gyri of the brain (Hu et al., 2013). In line with these findings, a postmortem study showed that the proliferation of neural stem cells was diminished in the hippocampus of patients with schizophrenia (Reif et al., 2006). Another study reported decreased VEGF
http://dx.doi.org/10.1016/j.psychres.2015.04.020 0165-1781/& 2015 Elsevier Ireland Ltd. All rights reserved.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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expression in the brain among patients with schizophrenia (Fulzele and Pillai, 2009). However, a recent clinical study found no significant difference in serum VEGF levels between patients with first-episode psychosis and healthy controls (Di Nicola et al., 2013). A possible explanation for these divergent results is that patients with first-episode psychosis in the study by Di Nicola et al. (2013) were not specifically diagnosed with schizophrenia. Indeed, clinical data are not yet available regarding VEGF levels in patients with schizophrenia. We hypothesized that VEGF might be associated with the development of or improvement in schizophrenia as a neurotrophic factor. The aim of this study was to determine whether or not there was a difference in plasma VEGF levels between patients with schizophrenia and healthy controls. We also explored alterations in plasma VEGF levels in patients with schizophrenia before and after treatment with antipsychotic agents. Additionally, we assessed whether plasma VEGF levels correlated with smoking status and duration and considered such variables to be covariants because some studies have suggested that smoking, a known contributing factor of endothelial damage, may affect plasma or serum VEGF levels (Schmidt-Lucke et al., 2005).
density of the color reaction in the wells was read using a microtiter plate reader (μQuant, Winooski, VT, USA) set to 450 nm. The intra- and inter-assay coefficients of variation were below 7%. The concentrations of the samples in each plate were calculated according to a standard curve.
2. Methods
3.1. Demographic data
2.1. Subjects
Table 1 presents demographic data for the 100 subjects in this study. There were no significant differences in age or sex between patients with schizophrenia and healthy controls. There was a trending difference in body mass index (BMI) between the two groups (t¼ 1.904, p¼ 0.060). In the entire sample, there were no significant correlations between plasma VEGF levels and sex, age, or BMI (data not shown). The distribution of smoking status did not significantly differ between patients with schizophrenia and healthy controls (χ2 ¼0.508, p¼ 0.476). Among smokers, the number of cigarettes smoked per day and duration of smoking did not differ between patients with schizophrenia and healthy controls (t¼0.128, d.f.¼21, p¼0.900, t¼ 0.119, d. f.¼21, p¼0.907, respectively). Across all subjects, mean plasma VEGF level (85.09776.14 pg/mL) in smokers was higher than that in
This study included 50 patients with schizophrenia hospitalized in the Department of Psychiatry, Ansan Hospital, College of Medicine, Korea University, Kyunggi, Korea. All patients were interviewed by a trained psychiatrist using the Structured Clinical Interview for DSM-IV (SCID) (First et al., 1998). Patients were either medication-naïve or medication-free for at least 4 weeks prior to assessment. Patients (22 males and 28 females; mean age7 S.D.¼ 33.17 8.9 years) were diagnosed with schizophrenia according to DSM-IV criteria. We excluded patients with any past history of Axis I psychiatric disorders other than schizophrenia, such as mood disorders and alcohol and/or substance dependence. We also excluded patients with a past history of chronic adverse events, such as tardive dyskinesia, or with a personal history of medical illness including diabetes mellitus or hypertension, as well as patients who were pregnant or lactating. Patients with schizophrenia were treated with risperidone (n ¼24), amisulpride (n¼ 14), aripiprazole (n¼7), quetiapine (n¼3), or olanzapine (n¼ 2), at a flexible dosage based on their psychiatric symptoms. The group of 50 healthy controls (24 males and 26 females; mean age7S. D.¼ 32.777.2 years) consisted of randomly selected healthy volunteers who participated in this study at the Korea University Ansan Hospital. Healthy controls were evaluated using the SCID. Controls had no personal or familial psychiatric or medical history. All subjects were free of chronic and acute physical illnesses within 4 weeks prior to enrollment. All controls had normal laboratory findings on blood chemistry, renal function, thyroid function, liver function, and on an electrocardiography. The study protocol was approved by the Ethics Committee of Korea University. Written informed consent was obtained from each subject. 2.2. Assessment 2.2.1. Clinical evaluation A trained psychiatrist assessed the psychopathological status of patients using the Positive and Negative Syndrome Scale (PANSS) (Kay et al., 1987). Assessment occurred for all patients with schizophrenia at baseline and at the end of 6 weeks of treatment. Total scores and subscores for positive, negative, and general symptoms were collected. In addition, PANSS cognitive factor subscore was assessed. One proposed model of the cognitive factor of schizophrenia includes three PANSS items: ‘conceptual disorganization’ (P2), ‘difficulty in abstract thinking’ (N5), and ‘poor attention’ (G11) (Wallwork et al., 2012; Rodriguez-Jimenez et al., 2013). To evaluate the responsiveness of patients to the treatment, response was defined as demonstration of at least 30% improvement in PANSS total scores at endpoint compared to baseline (Hermes et al., 2012). 2.2.2. Plasma VEGF measurement For all patients and healthy controls, blood samples were drawn from the antecubital veins of subjects between 7 and 8 a.m. following an overnight fast. Approximately 10 ml of blood was collected and placed in lithium heparin vacuum tubes. VEGF levels were assayed using the sandwich ELISA method (R&D Systems, Minneapolis, MN, USA) following the manufacturer's instructions. The optical
2.3. Statistical analysis Plasma VEGF levels showed a normal distribution using the Kolmogorov– Smirnov test (Kolmogorov–Smirnov Z¼1.153, p ¼0.140). Study groups were compared on continuous variables using two-tailed t-tests, analyses of variance (ANOVA), and Kruskal–Wallis tests. For discrete variables, study groups were compared using a chi-square test. When the sample sizes of groups, for example, subject groups receiving different antipsychotic agents, were small and uneven, a non-parametric approach was used. General linear modeling was used while controlling for covariates. Differences in the patient group by medication type were also analyzed. Bonferroni corrections were used to control for multiple testing. Pearson's correlation coefficients were calculated to examine the relationships between plasma VEGF levels and clinical variables. Pre-treatment and posttreatment VEGF levels and PANSS scores of patients with schizophrenia were compared using paired t-tests. Data are presented as mean 7 S.D. The null hypothesis was rejected at po 0.05. The statistical package used for analysis was SPSS 12.0.
3. Results
Table 1 Demographic data and clinical characteristics of study subjects. Schizophrenia (n¼ 50)
Healthy controls (n¼50)
Gender (male/female)
22/28
24/26
Age (years)
33.17 8.9
32.7 7 7.2
2
BMI (kg/m )
21.8 7 2.8
23.1 73.9
Smoker (%)
13(26%)
10(20%)
χ2 ¼ 0.161, p ¼ 0.841 t ¼ 0.272, p ¼ 0.786 t ¼1.904, p ¼ 0.060 χ2 ¼ 0.508, p ¼ 0.476
Medication status when entering the study Medication-naive 31 Medication-free 19 PANSS at baseline Total score 98.2 717.5 Positive symptom 27.9 76.9 Negative symptom 20.9 76.3 General symptom 49.47 9.2 Cognitive factor 8.5 72.9 PANSS after 6-week treatment Total score 57.1 7 13.2 Positive symptom 14.2 7 4.2 Negative symptom 13.4 7 4.7 General symptom 29.5 76.9 Cognitive factor 4.7 71.5 BMI: body mass index. PANSS: the Positive and Negative Syndrome Scale for schizophrenia.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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(63.31749.42 pg/mL) in non-smokers, but this was not statistically significant (t¼ 1.622, d.f.¼ 98, p¼ 0.108). VEGF levels did not significantly correlate with the number of cigarettes smoked per day (r¼0.160, p¼ 0.112). However, there was a significant correlation between VEGF level and duration of smoking (r¼0.259, p¼0.012).
were significantly increased compared to baseline (46.93748.02 pg/mL) (t¼ 2.091, d.f.¼30, p¼ 0.049). Plasma VEGF did not correlate with PANSS total or subscale scores, or with chlorpromazine-equivalent doses (p40.05).
3.2. Plasma VEGF
4. Discussion
There was a difference in baseline plasma VEGF levels between patients with schizophrenia (47.25 747.12 pg/mL) and healthy controls (89.38 758.62 pg/mL), (t ¼3.961, d.f. ¼98, p o0.01). When controlling for BMI (p ¼0.381) and duration of smoking (p ¼0.002) as covariates, VEGF levels in patients with schizophrenia were still lower than those in healthy controls (F (1, 96) ¼3.949, p o0.01). Mean plasma VEGF level at the end of the 6-week treatment period was 138.947175.07 pg/mL in patients. There was a significant alteration in plasma VEGF levels between baseline and at the end of the 6-week treatment period in patients with schizophrenia (t¼ 3.003, d.f.¼49, p¼0.005).
In this study we found that plasma VEGF levels at baseline were significantly lower in patients with schizophrenia who were either medication-naïve or medication-free compared to healthy control subjects. In addition, we observed an increase in plasma VEGF levels after 6 weeks of medication treatment in patients with schizophrenia. To our knowledge, this is the first study to examine changes in plasma VEGF levels in patients with schizophrenia before and after treatment. One recent clinical study examined serum VEGF levels in medicationnaïve, first-episode psychosis patients aged 15–25 years before and after a 12-week treatment with quetiapine (Murphy et al., 2014). They found no significant difference in serum VEGF levels between such patients and healthy controls and no significant treatment changes in VEGF levels. An increase in serum VEGF was also reported to be positively correlated with a reduction in positive symptoms. However, our results indicate a significant increase in plasma VEGF levels after 6 weeks of treatment in patients with schizophrenia, which did not correlate with changes in PANSS scores. Previous postmortem studies found reduced VEGF activity in the brain among patients with schizophrenia. One study examining mRNA levels of VEGF in the dorsolateral prefrontal cortex area in 16 patients with schizophrenia and 18 control subjects found a significant reduction in VEGF mRNA expression in the dorsolateral prefrontal cortex of patients with schizophrenia (Fulzele and Pillai, 2009). Additionally, another postmortem study observed a significant decrease in VEGF receptor-2 levels in the prefrontal cortex of 10 patients with schizophrenia (Howell et al., 2011). VEGF seems to play a critical role in adult neurogenesis (Palmer et al., 2000). In fact, proliferation of neural stem cells in the hippocampus, the first step of adult neurogenesis, seems to be significantly reduced in patients with schizophrenia in comparison to healthy controls (Reif et al., 2006). Although most patients with schizophrenia in postmortem studies received antipsychotic medications, such findings suggest a decrease in central VEGF activity and adult neurogenesis in schizophrenia. Animal studies suggest that treatment with antipsychotic agents affects the activation of VEGF and neurogenesis. One study found that a 14-day administration of haloperidol and olanzapine increased levels of VEGF and angiogenesis in the hippocampus of rats (Pillai and Mahadik, 2006). Furthermore, 45-day treatment with olanzapine without haloperidol also enhanced VEGF levels in rats (Pillai and Mahadik, 2006). Olanzapine reportedly increases cell proliferation in the periventricular zone and prefrontal cortex of rats (Green et al., 2006). Other studies examined whether chronic administration of haloperidol and risperidone have any effect on cell genesis and cell survival in the hippocampus of adult rats treated with ketamine and saline (Keilhoff et al., 2010), finding that both haloperidol and risperidone reduce ketamine-induced cell death and enhance cell proliferation in the dentate gyrus of both ketamine- and saline-treated rats. These effects of risperidone and (to a lesser extent) haloperidol seem to be associated with the activation of VEGF. These findings are consistent with our observation that plasma VEGF levels in patients with schizophrenia increased after 6 weeks of treatment with atypical antipsychotics. However, we did not find any relationship between the increase of plasma VEGF levels and decrease in PANSS cognitive factor, positive, negative symptom subscales in patients with schizophrenia. Our study showed that patients with schizophrenia have lower plasma VEGF levels than controls before treatment and that plasma VEGF levels in patients increase after 6 weeks of treatment with
3.3. Symptoms and plasma VEGF In patients with schizophrenia patients, the mean total PANSS scores were 98.2 717.5 at baseline and 57.1 713.2 at the end of the 6-week treatment period (t¼ 11.014, d.f. ¼49, p o0.001). Subscores for positive, negative, and general symptoms and subscores for the cognitive factor significantly improved from baseline to the end of treatment (p o0.01). Among all patients, 35 (70%) were responders and 15 (30%) were non-responders. There were no differences in change in mean plasma VEGF levels from baseline to the end of treatment between responders and non-responders (t¼1.729, d.f. ¼48, p ¼0.094, t ¼0.995, d.f. ¼ 48, p ¼0.329, respectively). Plasma VEGF levels in patients with schizophrenia were not significantly correlated with total scores and subscores of the PANSS both at baseline and the end of treatment (p 40.05). When controlling for smoking duration, there were also no significant correlations between plasma VEGF levels or PANSS total and subscale scores. 3.4. Antipsychotic medications and plasma VEGF Differences in the patient group based on medication type were examined. There were no significant differences in plasma VEGF levels at baseline (χ2 ¼3.787, p¼ 0.436) or at the end of the 6-week treatment period (χ2 ¼6.583, p ¼0.160) between groups receiving the five different antipsychotic medications. There was no significant difference in the distribution of responders and nonresponders among the antipsychotic groups (χ2 ¼2.637, p ¼0.620). The chlorpromazine-equivalent dose did not correlate with plasma VEGF level at the end of the 6-week treatment period (r¼ 0.162, p¼0.385) or changes in VEGF levels from baseline to post-treatment (r¼ 0.176, p¼0.343). The chlorpromazine-equivalent dose also did not differ between responders (408.47200.4 mg) and non-responders (491.97231.6 mg) (t¼1.031, d.f.¼48, p¼0.311). 3.5. Plasma VEGF in medication-naïve patients Plasma VEGF levels at baseline were significantly lower in medication-naïve and medication-free patients than in healthy controls (F (2, 97)¼7.779, p¼0.001). After controlling for BMI (p¼0.402) and smoking duration (p¼0.002), VEGF levels in medication-naïve and medication-free patients were still lower than those in healthy controls (F (2, 95)¼8.181, p¼0.01). However, plasma VEGF levels after treatment did not differ among medication-naïve and medication-free patients and healthy controls (F (2, 97)¼1.784, p¼0.175). In medication-naïve patients, plasma VEGF levels (145.307209.02 pg/mL) at the end of treatment
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
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atypical antipsychotics. Animal studies show that dopamine stimulation inhibits angiogenesis via decreased functions of VEGF and VEGF receptors in tumor tissues (Basu et al., 2001; Teunis et al., 2002; Asada et al., 2008). An in vitro study with non-functioning pituitary adenomas demonstrated that cabergoline, a dopamine D2 receptor (DR2) agonist, reduces VEGF secretion and cell viability, and that this inhibitory effect of cabergoline is blocked by sulpiride, a selective DR2 antagonist in DR2-expressing pituitary adenomas (Gagliano et al., 2013). Moreover, other animal studies with antipsychotics have suggested that risperidone and olanzapine increase the phosphorylation of the cAMP response element binding protein (CREB) in the hippocampus (Keilhoff et al., 2010; Réus et al., 2012), and that these antipsychotics enhance VEGF expression therein (Pillai and Mahadik, 2006; Keilhoff et al., 2010). There is experimental evidence that adult neurogenesis requires increased activation of VEGF and CREB in the brain (Lee et al., 2009; Oh et al., 2012). The above findings might explain the increase of plasma VEGF level after 6 weeks of treatment with antipsychotics in patients with schizophrenia in our study. Our findings indicated that the plasma VEGF level in smokers is higher than that in nonsmokers, but this was not statistically significant. One previous study suggested that smoking causes an acute increase in plasma VEGF in some, but not all, smokers with non-insulin-dependent diabetes mellitus (Wasada et al., 1998). Several clinical studies also reported similar plasma VEGF levels between smokers and non-smokers in healthy controls (Belgore et al., 2000; Schmidt-Lucke et al., 2005). However, our findings indicate that plasma VEGF levels were significantly correlated with smoking duration. Therefore, we controlled for smoking duration when analyzing plasma VEGF levels. There are several limitations to this study. First, we used relatively small sample sizes, particularly for comparing differences among medication type. Second, we examined only VEGF levels in plasma and the range of VEGF levels in our study was quite broad. VEGF is produced by various cell types, including endothelial cells, neutrophils, platelets, and mononuclear cells (Dvorak, 2002). It has been reported that VEGF levels tend to change in the same direction in plasma, serum, and the cerebrospinal fluid of patients with cerebral ischemia (Scheufler et al., 2003). However, the source of measured plasma VEGF in our subjects was not clear. Consequently, we were unable to determine whether changes in plasma VEGF levels reflect any changes in brain VEGF. Therefore we cannot explain the mechanism for VEGF alterations in schizophrenia. In this study we did not observe significant differences between plasma VEGF levels at baseline and at the end of the 6-week treatment period between responders and non-responders.
5. Conclusion We found that baseline plasma VEGF levels were lower in medication-naïve or medication-free schizophrenia patients compared to healthy controls and that VEGF levels were elevated in patients after treatment with antipsychotics. Although the mechanism of VEGF in the pathophysiology of schizophrenia has not yet been explained, it may be that VEGF has a neuroprotective role in the improvement of schizophrenia or in the treatment effects of antipsychotics.
Acknowledgments Funding for this study was provided by a grant from the Korea Health Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (A120051).
References Asada, M., Ebihara, S., Numachi, Y., Okazaki, T., Yamanda, S., Ikeda, K., Yasuda, H., Sora, I., Arai, H., 2008. Reduced tumor growth in a mouse model of schizophrenia, lacking the dopamine transporter. International Journal of Cancer 123, 511–518. Basu, S., Nagy, J.A., Pal, S., Vasile, E., Eckelhoefer, I.A., Bliss, V.S., Manseau, E.J., Dasgupta, P.S., Dvorak, H.F., Mukhopadhyay, D., 2001. The neurotransmitter dopamine inhibits angiogenesis induced by vascular permeability factor/ vascular endothelial growth factor. Nature Medicine 7, 569–574. Belgore, F.M., Lip, G.Y., Blann, A.D., 2000. Vascular endothelial growth factor and its receptor, Flt-1, in smokers and non-smokers. British Journal of Biomedical Science 57, 207–213. deVries, C., Escobedo, J.A., Ueno, H., Houck, K., Ferrara, N., Williams, L.T., 1992. The fms-like tyrosine kinase, a receptor for vascular endothelial growth factor. Science 255, 989–991. Di Nicola, M., Cattaneo, A., Hepgul, N., DiForti, M., Aitchison, K.J., Janiri, L., Murray, R. M., Dazzan, P., Pariante, C.M., Mondelli, V., 2013. Serum and gene expression profile of cytokines in first-episode psychosis. Brain, Behavior, and Immunity 31, 90–95. Dvorak, H.F., 2002. Vascular permeability factor/vascular endothelial growth factor: a critical cytokine in tumor angiogenesis and a potential target for diagnosis and therapy. Journal of Clinical Oncology 20, 4368–4380. Ferrara, N., Gerber, H.P., LeCouter, J., 2003. The biology of VEGF and its receptors. Natural Medicine 9, 669–676. First, M., Spitzer, R.L., Gibbon, M., William, J.B., 1998. Structured Clinical Interview for DSM-IV Axis I Disorder – Patient Edition (SCID-I/P, version 2.0). New York State Psychiatric Institute, New York. Fulzele, S., Pillai, A., 2009. Decreased VEGF mRNA expression in the dorsolateral prefrontal cortex of schizophrenia subjects. Schizophrenia Research 115, 372–373. Gagliano, T., Filieri, C., Minoia, M., Buratto, M., Tagliati, F., Ambrosio, M.R., Lapparelli, M., Zoli, M., Frank, G., degliUberti, E., Zatelli, M.C., 2013. Cabergoline reduces cell viability in non functioning pituitary adenomas by inhibiting vascular endothelial growth factor secretion. Pituitary 16, 91–100. Green, W., Patil, P., Marsden, C.A., Bennett, G.W., Wigmore, P.M., 2006. Treatment with olanzapine increases cell proliferation in the subventricular zone and prefrontal cortex. Brain Research 1070, 242–245. Hermes, E.D., Sokoloff, D., Stroup, T.S., Rosenheck, R.A., 2012. Minimum clinically important difference in the Positive and Negative Syndrome Scale with data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE). The Journal of Clinical Psychiatry 73, 526–532. Howell, K.R., Kutiyanawalla, A., Pillai, A., 2011. Long-term continuous corticosterone treatment decreases VEGF receptor-2 expression in frontal cortex. PLoS One 6, e20198. Hu, M., Li, J., Eyler, L., Guo, X., Wei, Q., Tang, J., Liu, F., He, Z., Li, L., Jin, H., Liu, Z., Wang, J., Liu, F., Chen, H., Zhao, J., 2013. Decreased left middle temporal gyrus volume in antipsychotic drug-naive, first-episode schizophrenia patients and their healthy unaffected siblings. Schizophrenia Research 144, 37–42. Jin, K., Zhu, Y., Sun, Y., Mao, X.O., Xie, L., Greenberg, D.A., 2002. Vascular endothelial growth factor (VEGF) stimulates neurogenesis in vitro and in vivo. Proceedings of the National Academy of Sciences of the United States of America 99, 11946–11950. Kay, S.R., Fiszbein, A., Opler, L.A., 1987. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13, 261–276. Keilhoff, G., Grecksch, G., Bernstein, H.G., Roskoden, T., Becker, A., 2010. Risperidone and haloperidol promote survival of stem cells in the rat hippocampus. European Archives of Psychiatry and Clinical Neuroscience 260, 151–162. Khaibullina, A.A., Rosenstein, J.M., Krum, J.M., 2004. Vascular endothelial growth factor promotes neurite maturation in primary CNS neuronal cultures. Brain research. Developmental Brain Research 148, 59–68. Krum, J.M., Rosenstein, J.M., 1998. VEGF mRNA and its receptor flt-1 are expressed in reactive astrocytes following neural grafting and tumor cell implantation in the adult CNS. Experimental Neurology 154, 57–65. Lee, J.S., Jang, D.J., Lee, N., Ko, H.G., Kim, H., Kim, Y.S., Kim, B., Son, J., Kim, S.H., Chung, H., Lee, M.Y., Kim, W.R., Sun, W., Zhuo, M., Abel, T., Kaang, B.K., Son, H., 2009. Induction of neuronal vascular endothelial growth factor expression by cAMP in the dentate gyrus of the hippocampus is required for antidepressantlike behaviors. The Journal of Neuroscience 29, 8493–8505. Murphy, B.P., Pang, T.Y., Hannan, A.J., Proffitt, T.M., McConchie, M., Kerr, M., Markulev, C., O’Donnell, C., McGorry, P.D., Berger, G.E., 2014. Vascular endothelial growth factor and brain-derived neurotrophic factor in quetiapine treated first-episode psychosis. Schizophrenia Research and Treatment 2014, 719395. Oh, D.H., Kim, B.W., Choi, M., Lee, G., Choi, J.S., Son, H., 2012. Changes in vascular endothelial growth factor (VEGF) induced by the Morris water maze task. Molecules and Cells 33, 295–300. Palmer, T.D., Willhoite, A.R., Gage, F.H., 2000. Vascular niche for adult hippocampal neurogenesis. The Journal of Comparative Neurology 425, 479–494. Pillai, A., Mahadik, S.P., 2006. Differential effects of haloperidol and olanzapine on levels of vascular endothelial growth factor and angiogenesis in rat hippocampus. Schizophrenia Research 87, 48–59. Réus, G.Z., Abelaira, H.M., Agostinho, F.R., Ribeiro, K.F., Vitto, M.F., Luciano, T.F., Souza, C.T., Quevedo, J., 2012. The administration of olanzapine and fluoxetine has synergistic effects on intracellular survival pathways in the rat brain. Journal of Psychiatric Research 46, 1029–1035.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
B.-H. Lee et al. / Psychiatry Research ∎ (∎∎∎∎) ∎∎∎–∎∎∎ Reif, A., Fritzen, S., Finger, M., Strobel, A., Lauer, M., Schmitt, A., Lesch, K.P., 2006. Neural stem cell proliferation is decreased in schizophrenia, but not in depression. Molecular Psychiatry 11, 514–522. Rodriguez-Jimenez, R., Bagney, A., Mezquita, L., Martinez-Gras, I., Sanchez-Morla, E. M., Mesa, N., Ibanez, M.I., Diez-Martin, J., Jimenez-Arriero, M.A., Lobo, A., Santos, J.L., Palomo, T., 2013. Cognition and the five-factor model of the positive and negative syndrome scale in schizophrenia. Schizophrenia Research 143, 77–83. Scheufler, K.M., Drevs, J., vanVelthoven, V., Reusch, P., Klisch, J., Augustin, H.G., Zentner, J., Marme, D., 2003. Implications of vascular endothelial growth factor, sFlt-1, and sTie-2 in plasma, serum and cerebrospinal fluid during cerebral ischemia in man. Journal of Cerebral Blood Flow and Metabolism 23, 99–110. Schmidt-Lucke, C., Belgore, F., Reinhold, D., Ansorge, S., Klein, H.U., Schmidt-Lucke, J.A., Lip, G.Y., 2005. Soluble vascular endothelial growth factor, soluble VEGF receptor Flt-1 and endothelial function in healthy smokers. International Journal of Cardiology 100, 207–212.
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Sun, Y., Jin, K., Xie, L., Childs, J., Mao, X.O., Logvinova, A., Greenberg, D.A., 2003. VEGF-induced neuroprotection, neurogenesis, and angiogenesis after focal cerebral ischemia. The Journal of Clinical Investigation 111, 1843–1851. Teunis, M.A., Kavelaars, A., Voest, E., Bakker, J.M., Ellenbroek, B.A., Cools, A.R., Heijnen, C.J., 2002. Reduced tumor growth, experimental metastasis formation, and angiogenesis in rats with a hyperreactive dopaminergic system. FASEB Journal 16, 1465–1467. Wallwork, R.S., Fortgang, R., Hashimoto, R., Weinberger, D.R., Dickinson, D., 2012. Searching for a consensus five-factor model of the Positive and Negative Syndrome Scale for schizophrenia. Schizophrenia Research 137, 246–250. Wasada, T., Kawahara, R., Katsumori, K., Naruse, M., Omori, Y., 1998. Plasma concentration of immunoreactive vascular endothelial growth factor and its relation to smoking. Metabolism: Clinical and Experimental 47, 27–30. Yang, S.Z., Zhang, L.M., Huang, Y.L., Sun, F.Y., 2003. Distribution of Flk-1 and Flt-1 receptors in neonatal and adult rat brains. The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology 274, 851–856.
Please cite this article as: Lee, B.-H., et al., Alterations in plasma vascular endothelial growth factor levels in patients with schizophrenia before and after treatment. Psychiatry Research (2015), http://dx.doi.org/10.1016/j.psychres.2015.04.020i
