American Journal of Emergency Medicine 33 (2015) 497–500
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Original Contribution
The relationship between vascular inflammation and target organ damage in hypertensive crises☆,☆☆ Mustafa Karabacak, MD a,⁎, Mehmet Yigit, MD b, Kenan Ahmet Turkdogan, MD b, Mehmet Sert, MD c a b c
Department of Cardiology, Isparta State Hospital, Isparta, Turkey Department of Emergency Medicine, Bezimialem Foundation University, Istanbul, Turkey Department of Nephrology, Isparta State Hospital, Isparta, Turkey
a r t i c l e
i n f o
Article history: Received 2 October 2014 Received in revised form 8 November 2014 Accepted 9 November 2014
a b s t r a c t Objective: Hypertensive crises, divided depending on the presence of target organ damage (TOD), are associated with increased cardiovascular mortality and morbidity. Monocyte chemoattractant protein-1 (MCP-1) is responsible for the recruitment of monocytes to sites of vascular inflammation. The aim of this study was to evaluate the role of vascular inflammation in development of TOD. Method: The patients were categorized according to the presence of TOD. Thirty-three patients (15 female; mean age, 68 ± 12 y) with TOD and 30 patients (14 female; mean age, 64 ± 12 y) without TOD were included to the study. In addition to routine laboratory parameters, neutrophil-lymphocyte ratio, uric acid, C-reactive protein (CRP), high sensitive CRP, and plasma MCP-1 levels were evaluated. Results: Neutrophil counts, white blood cells, high sensitive CRP, and uric acid levels were higher in patients with hypertensive crises. More importantly, CRP (7.2 mg/dL [2-37.8 mg/dL] vs 4.6 mg/dL [1.5-14 mg/dL] vs 2.7 mg/dL [1-8.1 mg/dL], P b .01) and MCP-1 levels (546 pg/mL [236-1350 pg/mL] vs 407 pg/mL [78-942 pg/mL] vs 264 pg/mL [34-579 pg/mL], P b .01) were higher in the group with TOD compared with other groups. Conclusion: In conclusion, plasma MCP-1 levels were significantly higher in patients with TOD. According to our results, we suggest that increased vascular inflammation and MCP-1 levels might be associated with the development of TOD in hypertensive crisis. © 2014 Elsevier Inc. All rights reserved.
1. Introduction In the development of hypertension (HT), chemokines play an important role by controlling the vascular inflammation [1]. They participate in the migration of leukocytes in the course of HT into the blood vessel wall [2,3]. The inflammatory infiltrate in the vascular wall causes an increase in blood pressure (BP) [1]. Moreover, the studies in the past few decades have indicated that vascular wall inflammation plays a key role in the pathogenesis and progression of atherosclerosis, cardiovascular disease, and HT [4-6]. Monocyte/macrophage infiltration is almost invariably accompanied in hypertensive target organ damage [3]. Monocyte chemoattractant protein-1 (MCP-1), also known as CCL2, contributes to the pathogenesis of atherosclerosis by promoting the recruitment of inflammatory cells to the vessel wall [7]. It is responsible for the recruitment of monocytes to sites of vascular inflammation [8-10]. Previously, elevated concentrations of MCP-1 with other
☆ Sources of funding: None of the authors of this article had any financial relationships with other individuals or organizations. ☆☆ Conflict of interest: The authors disclose that they have no conflict of interest to declare. ⁎ Corresponding author. Modern Evler Mah 142.Cadde, İksir Sitesi No 7/10 32100. Tel.: +90 5053912523; fax: +90 246 2237831. E-mail address: [email protected] (M. Karabacak). http://dx.doi.org/10.1016/j.ajem.2014.11.014 0735-6757/© 2014 Elsevier Inc. All rights reserved.
chemokines have been described in patients with essential HT and endothelial dysfunction [11]. Hypertensive crises are associated with increased cardiovascular mortality and morbidity [12] and characterized by severe HT [13]. They are divided depending on the presence of TOD [12,13]. There are numerous information on the contribution of inflammation to vascular damage in patients with HT [14-16]. However, the effect of vascular inflammation to the pathophysiology of HT crises is still unclear. Accordingly, we aimed to investigate the role of vascular inflammation in hypertensive crises and the relationship with the development of TOD. 2. Materials and methods 2.1. Patients and methods This study included 63 consecutive patients who presented to our emergency department with a diagnosis of hypertensive crisis between September 2013 and February 2014. The patients were categorized according to the presence of TOD. Thirty-three patients with TOD (15 female; mean age, 68 ± 12 y) and 30 patients without TOD (14 female; mean age, 64 ± 12 y) were enrolled. The control group consisted of 30 normotensive control patients (15 female; mean age, 65 ± 13 y). Hypertensive crisis was defined as systolic BP more than
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180 mm Hg and/or diastolic BP more than 120 mm Hg. Acute coronary syndrome (myocardial infarction with/without ST elevation, unstable angina pectoris), acute heart failure, acute pulmonary edema, cerebrovascular events (ischemic or hemorrhagic, transient ischemic attack), hypertensive encephalopathy, aortic dissection, hypertensive crises with retinopathy, microangiopathy, or acute renal failure were considered TOD. The systolic and diastolic BPs of the control group were less than 140/90 mm Hg. Exclusion criteria were any drug use that could potentially influence inflammatory conditions, hepatic dysfunction, hematologic disorders, history of malignancy, acute or chronic infection, and old stroke. Diabetes mellitus (DM) was defined as a fasting blood glucose level more than 126 mg/dL or use of antidiabetic drugs. Renal failure was defined as serum creatinine level more than 1.5 mg/dL in men and more than 1.4 mg/dL in women. The study was conducted in accordance with the guidelines proposed in the Declaration of Helsinki and approved by the local ethics committee. Informed consent was obtained from the parents of each subject.
Table 1 Demographic, clinical, and laboratory characteristics of TOD(+), TOD(−), and control groups
2.2. Measurement of BP
Abbreviations: BP1, before antihypertensive treatment; BP2, after antihypertensive treatment; CAD, chronic artery disease; CRF, chronic renal failure; BUN, blood urea nitrogen; AST, aspartate transaminase; ALT, alanine transaminase. P values represent the comparisons among 3 groups. ⁎ P b .01 vs control. ⁎⁎ P b .01 vs TOD(−).
In the emergency department, BP was measured with a mercury sphygmomanometer on the right arm; the first and fifth phases of Korotkoff sounds were used for systolic and diastolic BP, respectively. Three BP measurements were taken at 5-minute intervals by a physician with the patient in a seated position after at least a 5-minute rest, using an appropriately sized cuff. The mean of the 3 readings was considered the final BP value. 2.3. Biochemical measurements Blood samples were drawn from the antecubital vein by careful venipuncture into a sterile 21-gauge syringe without stasis. The samples were studied within 20 minutes, with the exception of whole blood count. The blood sampling and processing of samples were standardized. They were collected in dipotassium EDTA tubes and analyzed with the same automatic blood counter (Beckman Coulter Co, Miami, USA) within 5 minutes. To minimize degradation, the blood samples to determine MCP-1 levels were collected in ice-chilled disposable polypropylene tubes containing EDTA (1 mg/mL). The blood samples were rapidly separated by centrifugation in gel-containing vacuumed biochemistry tubes at 3000 rpm for 10 minutes, and the sera were stored in Eppendorf tubes (Eppendorf, Hamburg, Germany) at −80°C. 2.4. Measurement of MCP-1 levels Plasma MCP-1 levels were measured with the enzyme-linked immunosorbent assay (ELISA) method and determined using an ELISA kit (BMS281TEN; eBioscience, Vienna, Austria) according to the manufacturer’s protocols. The absorbance of the samples was measured at 450 nm using a Multiskan FC Microplate Photometer (Thermo Scientific Microplate Photometer, Multiskan FC, USA). The limit of detection was 2.31 pg/mL. The coefficient of interassay variation was 8.7%. 2.5. Statistical analysis Statistical analysis was performed using SPSS software, version 15 (SPSS, Chicago, IL). Distribution of continuous variables was tested by the Kolmogorov-Smirnov test. Continuous variables were expressed as mean ± SD or median and 25th to 75th percentile values as appropriate. Categorical variables were expressed as percentages. Statistical differences among groups were tested by one-way analysis of variance with post hoc Scheffé correction or Kruskal-Wallis test for parametric or nonparametric variables, respectively. The univariate linear regression model was used to adjust differences in MCP-1 for age and sex in the hypertensive crisis and control groups. Thereafter, linear regression analyses were performed stepwise to identify the possible association
Age, y Male/female, n/n Systolic BP1, mm Hg Diastolic BP1, mm Hg Systolic BP2, mm Hg Diastolic BP2, mm Hg HT, n (%) DM, n (%) CAD, n (%) CRF, n (%) BUN, mg/dL AST, U/L ALT, U/L Hemoglobin level, g/dL Platelet, ×103/mm3 MPV, fL
Control (n = 30)
TOD(−) (n = 30)
TOD(+) (n = 33)
P
65 ± 13 15/15 123 ± 7 76 ± 4 123 ± 7 76 ± 4 1 (3%) 0 (0%) 0 (0%) 0 (0%) 14 ± 4 19 ± 7 23 ± 7 14 ± 1.3 225 ± 79 8.4 ± 0.9
64 ± 12 16/14 209 ± 18⁎ 121 ± 6⁎ 160 ± 12⁎ 83 ± 9⁎ 21 (70%)⁎ 12 (40%)⁎
68 ± 12 18/15 213 ± 15⁎ 128 ± 13⁎,⁎⁎ 157 ± 12⁎ 82 ± 8⁎ 27 (82%)⁎ 16 (48%)⁎
4 (13%) 2 (6%) 19 ± 11 21 ± 5 20 ± 11 13.2 ± 1.8 257 ± 75 9.9 ± 1.2⁎
6 (20%) 3 (9%) 17 ± 6 24 ± 14 19 ± 7 13 ± 1.6 274 ± 76 10 ± 0.8⁎
.40 .82 b.001 b.001 b.001 b.001 b.01 b.01 .08 .26 .05 .07 .49 .14 .05 b.01
of MCP-1 as a dependent variable with potential confounding factors among the 3 groups. These confounders were systolic and diastolic BP before and after antihypertensive treatment, white blood cells (WBC), mean platelet volume (MPV), uric acid, C-reactive protein (CRP), high sensitive CRP, neutrophil counts, presence of DM, and HT. A P b .05 was considered statistically significant.
3. Results Baseline characteristics for all groups were presented in Table 1. Age and sex were comparable among the groups. Systolic and diastolic BP before and after antihypertensive treatment were higher in the hypertensive crisis groups compared with the control group (P b .01). Furthermore, diastolic BP before antihypertensive treatment was prominently higher in the patients with TOD (128 ± 13 mm Hg vs 121 ± 6 mm Hg vs 76 ± 4 mm Hg, respectively; P b .01). Presence of DM or HT was comparable in the groups with or without TOD. Mean platelet volume was higher in the hypertensive crises groups than in the control group. Neutrophil counts, WBC, high sensitive CRP, and uric acid levels were higher in the groups with or without TOD than in the control groups (Table 2). However, CRP (7.2 mg/dL [2-37.8 mg/dL] vs 4.6 mg/dL [1.5-14 mg/dL] vs 2.7 mg/dL [1-8.1 mg/dL]; P b .01) and MCP-1 levels (546 pg/mL [236-1350 pg/mL] vs 407 pg/mL [78-942 pg/mL] vs 264 pg/mL [34-579 pg/mL]; P b .01; Fig. 1) were higher in the group with TOD than other groups (Table 2). Table 2 Comparison of parameters associated with inflammation in TOD(+), TOD(−), and control groups
WBC, ×103/mL Neutrophils, ×103/mL Lymphocytes, ×103/mL NLR Uric acid, mg/dL Hs-CRP, mg/dL CRP, mg/dL MCP-1, pg/mL
Control (n = 30)
TOD(−) (n = 30)
TOD(+) (n = 33)
6.2 ± 1.4 3.60 ± 1.23 1.89 ± 0.34 2.01 ± 1.01 4.6 ± 1.3 1.3 (0.3-3.2) 2.7 (1-8) 264 (34-579)
8.5 ± 2.3⁎ 5.54 ± 1.69⁎ 2.40 ± 1.08 2.95 ± 2.00 6.5 ± 1.3⁎ 2.6 (1-5.5)⁎
8.8 ± 2.1⁎ 5.51 ± 2.09⁎ 2.25 ± 0.90 2.98 ± 2.01 7.2 ± 1.9⁎ 3.2 (1.5-6.3)⁎ 7.2 (2-38)⁎,⁎⁎
P
b.01 b.01 .17 .06 b.01 b.01 4.6 (2-14) b.01 407 (78-942) 546 (236-1350)⁎,⁎⁎ b.01
Abbreviations: NLR, neutrophil-lymphocyte ratio; Hs-CRP, high sensitive CRP. ⁎ P b .01 vs control. ⁎⁎ P b .01 vs TOD(−).
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Fig. 1. Monocyte chemoattractant protein-1 levels in hypertensive crises and control groups. Plasma MCP-1 levels are higher in patients with TOD than in the other groups (P b .001, unadjusted for age and sex).
Systolic and diastolic BP after and before antihypertensive treatment, MPV, WBC, neutrophil counts, CRP, high sensitive CRP, uric acid, and presence of DM or HT were different among the groups, and they were entered into linear regression in a stepwise method. Then, a multivariable analysis was performed among them to identify independent predictors associated with MCP-1. Among the univariate predictors, presence of DM (β = .563; 95% confidence interval [CI], 180.704363.684; P = .0001) and uric acid levels (β = .277; 95% CI, 10.19953.932; P = .005) were associated with plasma MCP-1 levels (Table 3). The relationship between plasma uric acid and MCP-1 levels was presented in Fig. 2. 4. Discussion Hypertensive crisis, associated with increased cardiovascular mortality and morbidity, is defined as a critical elevation of BP in which diastolic BP generally exceeds 120 mm Hg; it is traditionally divided depending on the presence of TOD and require early diagnosis and management to limit or prevent TOD, such as brain, kidney, heart, retina, and blood vessels [12,13]. The precise pathophysiology of hypertensive crisis is not well known. However, it is recognized that an individual is able to maintain organ perfusion with varying degrees of BP by autoregulatory mechanisms. According to 2 general theories, the pressure and humoral hypotheses, when a critical imbalance of pressure and/or humoral factors occurs, a series of pathologic events can lead to myointimal proliferation and fibrinoid necrosis [17]. This vascular damage can result in the deposition of platelets and fibrin as well as a breakdown of the normal autoregulatory function [18]. The numerous studies have demonstrated that vascular inflammation causes vascular damage and plays a key role in the pathogenesis and progression of atherosclerosis, cardiovascular disease, and HT [4-6,14-16]. At this point, chemokines play an important role in the control of vascular inflammation in the walls of blood vessels in HT [1]. Furthermore, the Table 3 The relationship of DM and uric acid levels on plasma MCP-1 levels Model
Presence of DM Uric acid
Unstandardized coefficients
Standardized coefficients
β
Std. error
β
95% CI
P
272.194 32.066
45.783 10.942
.563 .277
180.704-363.684 10.199-53.932
.000 .005
Abbreviation: Std., standard.
Fig. 2. Linear regression analysis of MCP-1 and uric acid levels in patients with hypertensive crisis. Uric acid level (β = .277; 95% CI, 10.199-53.932; P = .005) was dependently associated with plasma MCP-1 values.
inflammatory infiltrate in the vascular wall causes an increase in BP, and inhibition of these processes results in a decrease in BP [1]. They participate in the migration of leukocytes in the course of HT into the blood vessel wall [2,3]. Monocyte chemoattractant protein-1 contributes to the pathogenesis of atherosclerosis by promoting the recruitment of inflammatory cells to the vessel wall [7]. By activating the CCR2 receptor, it activates the recruitment of monocytes and leukocytes and migration to sites of vascular inflammation [8-10]. In some studies, elevated MCP-1 levels have been associated with an increased risk of death and recurrent ischemic events in acute coronary syndromes [19,20]. Moreover, a few years ago, elevated concentrations of MCP-1 with other chemokines have been described in patients with essential HT and endothelial dysfunction [11]. In another study, it has been shown that a lack of functional CCR2 receptors may be associated with the emergence of HT [21]. In experimental animals, several forms of HT induce infiltration of monocytes/macrophages into the vessel wall and in target organs, such as the kidney and the heart [15,16]. Moreover, hypertensive TOD is almost invariably accompanied by monocyte/macrophage infiltration into the involved organs [3]. Patients with elevated serum uric acid levels had a mean 10-fold increased risk of developing coronary artery disease or HT [22,23]. Hypertensive individuals with elevated serum uric acid levels had a significantly higher relative risk for both myocardial infarction and stroke [24]. These results strongly support the hypothesis that elevated serum uric acid level is an independent risk factor for HT-associated mortality and morbidity. In the present study, we found that uric acid levels were significantly higher independently of TOD in patients with hypertensive crises. Moreover, uric acid levels, in addition to the presence of DM, were positively associated with plasma MCP-1 levels (Fig. 2; Table 3). This result may be related with increased inflammation in hypertensive crises. Several studies show that higher levels of circulating CRP are related to higher BP [25-27]. Furthermore, tissue expression and plasma concentrations of inflammatory markers and chemokines such as CRP and MCP-1 are increased in experimental models of HT [28-30]. In addition, a recent study demonstrated that MCP-1 and CRP levels as inflammatory markers were higher in patients with HT. Moreover, this increase was correlated with systolic BP [31]. Similarly, in the present study, we found that CRP, high sensitive CRP, and MCP-1 levels were higher in the hypertensive crises group. Furthermore, CRP and MCP-1 levels were higher in the group with TOD than
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other groups. Unlikely, MCP-1 levels were associated with presence of DM and uric acid levels. 5. Study limitations Several limitations of this study should be considered. First, although there is no sample size was conducted, this study may be based on a relatively small sample size that has limited statistical power to detect small differences. Second, our analysis was based on a simple baseline determination at a single time point, which might not reflect patient status over long periods. 6. Conclusions In conclusion, plasma MCP-1 level was significantly higher in patients with hypertensive crises. More importantly, this elevation is more prominent in patients with TOD. In addition, MCP-1 levels were independently associated with uric acid and presence of DM. According to our results, we suggest that increased vascular inflammation and MCP-1 levels might be associated with the development of TOD in hypertensive crisis. References [1] Rodríguez-Iturbe B, Vaziri ND, Herrera-Acosta J, Johnson RJ. Oxidative stress, renal infiltration of immune cells and salt-sensitive hypertension: all for one and one for all. Am J Physiol 2004;286:606–16. [2] Johnson RJ, Alpers CE, Yoshimura A, Lombardi D, Pritzl P, Floege J, et al. Renal injury from angiotensin II-mediated hypertension. Hypertension 1992;19:464–74. [3] Haller H, Behrend M, Park JK, Schaberg T, Luft FC, Distler A. Monocyte infiltration and c-fms expression in hearts of spontaneously hypertensive rats. Hypertension 1995; 25:132–8. [4] Brasier AR, Recinos III A, Eledrisi MS. Vascular inflammation and the reninangiotensin system. Arterioscler Thromb Vasc Biol 2002;22:1257–66. [5] Schiffrin EL, Touyz RM. From bedside to bench to bedside: role of renin- angiotensinaldosterone system in remodeling of resistance arteries in hypertension. Am J Physiol Heart Circ Physiol 2004;287:H435–46. [6] Schiffrin EL. Vascular endothelin in hypertension. Vasc Pharmacol 2005;43:19–29. [7] Rossi D, Zlotnik A. The biology of chemokines and their receptors. Annu Rev Immunol 2000;18:217–42. [8] Charo IF, Ransohoff RM. The many roles of chemokines and chemokine receptors in inflammation. N Engl J Med 2006;354:610–21. [9] Bursill CA, Channon KM, Greaves DR. The role of chemokines in atherosclerosis: recent evidence from experimental models and population genetics. Curr Opin Lipidol 2004;15:145–9. [10] Boisvert WA. Modulation of atherogenesis by chemokines. Trends Cardiovasc Med 2004;14:161–5.
[11] De la Sierra A, Larrousse M. Endothelial dysfunction is associated with increased levels of biomarkers in essential hypertension. J Hum Hypertens 2010;24:373–9. [12] Mancia G, Fagard R, Narkiewicz K, Redo n ́ J, Zanchetti A, Böhm M, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The task force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens 2013;31:1281–357. [13] Van den Born BJ, Beutler JJ, Gaillard CA. Dutch guideline for the management of hypertensive crisis – 2010 revision. Neth J Med 2011;69:248–55. [14] Virdis A, Schiffrin EL. Vascular inflammation: a role in vascular disease in hypertension? Curr Opin Nephrol Hypertens 2003;12(2):181–7. [15] Hilgers KF. Monocytes/macrophages in hypertension. J Hypertens 2002;20:593–6. [16] Li J-J, Fang C-H, Huio R-T. Is hypertension an inflammatory disease? Med Hypotheses 2005;64:236–40. [17] Ault MJ, Ellrodt AG. Pathophysiological events leading to the end-organ effects of acute hypertension. Am J Emerg Med 1985;3:10–5. [18] Wallach R, Karp RB, Reves JG, Oparil S, Smith LR, James TN. Pathogenesis of paroxysmal hypertension developing during and after coronary bypass surgery: A study of hemodynamic and humoral factors. Am J Cardiol 1980;46:559–65. [19] de Lemos JA, Morrow DA, Sabatine MS, Murphy SA, Gibson CM, Antman EM, et al. Association between plasma levels of monocyte chemoattractant protein-1 and long-term clinical outcomes in patients with acute coronary syndromes. Circulation 2003;107:690–5. [20] de Lemos JA, Morrow DA, Blazing MA, Jarolim P, Wiviott SD, Sabatine MS, et al. Serial measurement of monocyte chemoattractant protein-1 after acute coronary syndromes: results from the A to Z trial. J Am Coll Cardiol 2007;50:2117–24. [21] Mettimano M, Specchia ML, Ianni A, Arzani D, Ricciardi G, Savi L, et al. CCR5 and CCR2 gene polymorphisms in hypertensive patients. Br J Biomed Sci 2003;60:19–21. [22] Campion EW, Glynn RJ, DeLabry LO. Asymptomatic hyperuricemia. Risks and consequences in the Normative Aging Study. Am J Med 1987;82:421–6. [23] Fessel WJ. High uric acid as an indicator of cardiovascular disease. Independence from obesity. Am J Med 1980;68:401–4. [24] Ward HJ. Uric acid as an independent risk factor in the treatment of hypertension. Lancet 1998;352:670–1. [25] Sesso HD, Buring JE, Rifai N, Blake GJ, Gaziano JM, Ridker PM. C-reactive protein and the risk of developing hypertension. J Am Med Assoc 2003;290:2945–51. [26] Bautista LE, Lopez-Jaramillo P, Vera LM, Casas JP, Otero AP, Guaracao AI. Is C-reactive protein an independent risk factor for essential hypertension? J Hypertens 2001;19: 857–61. [27] Engstrom G, Janzon L, Berglund G, Lind P, Stavenow L, Hedblad B, et al. Blood pressure increase and incidence of hypertension in relation to inflammation-sensitive plasma proteins. Arterioscler Thromb Vasc Biol 2002;22:2054–8. [28] Blake GJ, Ridker PM. Novel clinical markers of vascular wall inflammation. Circ Res 2001;89:763–71. [29] Diep QN, El Mabrouk M, Cohn JS, Endemann D, Amiri F, Virdis A, et al. Structure, endothelial function, cell growth, and inflammation in blood vessels of angiotensin IIinfused rats: role of peroxisome proliferator-activated receptor-g. Circulation 2002; 105:2296–302. [30] Ballantyne CM, Entman ML. Soluble adhesion molecules and the search for biomarkers for atherosclerosis. Circulation 2002;106:766–7. [31] Rabkin WS, Langer A, Ur E, Calciu CD, Leiter LA, on behalf of the CanACTFAST Study Investigators. Inflammatory biomarkers CRP, MCP-1, serum amyloid alpha and interleukin-18 in patients with HTN and dyslipidemia: impact of diabetes mellitus on metabolic syndrome and the effect of statin therapy. Hypertens Res 2013;36:550–8.
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Original Contribution
The relationship between vascular inflammation and target organ damage in hypertensive crises☆,☆☆ Mustafa Karabacak, MD a,⁎, Mehmet Yigit, MD b, Kenan Ahmet Turkdogan, MD b, Mehmet Sert, MD c a b c
Department of Cardiology, Isparta State Hospital, Isparta, Turkey Department of Emergency Medicine, Bezimialem Foundation University, Istanbul, Turkey Department of Nephrology, Isparta State Hospital, Isparta, Turkey
a r t i c l e
i n f o
Article history: Received 2 October 2014 Received in revised form 8 November 2014 Accepted 9 November 2014
a b s t r a c t Objective: Hypertensive crises, divided depending on the presence of target organ damage (TOD), are associated with increased cardiovascular mortality and morbidity. Monocyte chemoattractant protein-1 (MCP-1) is responsible for the recruitment of monocytes to sites of vascular inflammation. The aim of this study was to evaluate the role of vascular inflammation in development of TOD. Method: The patients were categorized according to the presence of TOD. Thirty-three patients (15 female; mean age, 68 ± 12 y) with TOD and 30 patients (14 female; mean age, 64 ± 12 y) without TOD were included to the study. In addition to routine laboratory parameters, neutrophil-lymphocyte ratio, uric acid, C-reactive protein (CRP), high sensitive CRP, and plasma MCP-1 levels were evaluated. Results: Neutrophil counts, white blood cells, high sensitive CRP, and uric acid levels were higher in patients with hypertensive crises. More importantly, CRP (7.2 mg/dL [2-37.8 mg/dL] vs 4.6 mg/dL [1.5-14 mg/dL] vs 2.7 mg/dL [1-8.1 mg/dL], P b .01) and MCP-1 levels (546 pg/mL [236-1350 pg/mL] vs 407 pg/mL [78-942 pg/mL] vs 264 pg/mL [34-579 pg/mL], P b .01) were higher in the group with TOD compared with other groups. Conclusion: In conclusion, plasma MCP-1 levels were significantly higher in patients with TOD. According to our results, we suggest that increased vascular inflammation and MCP-1 levels might be associated with the development of TOD in hypertensive crisis. © 2014 Elsevier Inc. All rights reserved.
1. Introduction In the development of hypertension (HT), chemokines play an important role by controlling the vascular inflammation [1]. They participate in the migration of leukocytes in the course of HT into the blood vessel wall [2,3]. The inflammatory infiltrate in the vascular wall causes an increase in blood pressure (BP) [1]. Moreover, the studies in the past few decades have indicated that vascular wall inflammation plays a key role in the pathogenesis and progression of atherosclerosis, cardiovascular disease, and HT [4-6]. Monocyte/macrophage infiltration is almost invariably accompanied in hypertensive target organ damage [3]. Monocyte chemoattractant protein-1 (MCP-1), also known as CCL2, contributes to the pathogenesis of atherosclerosis by promoting the recruitment of inflammatory cells to the vessel wall [7]. It is responsible for the recruitment of monocytes to sites of vascular inflammation [8-10]. Previously, elevated concentrations of MCP-1 with other
☆ Sources of funding: None of the authors of this article had any financial relationships with other individuals or organizations. ☆☆ Conflict of interest: The authors disclose that they have no conflict of interest to declare. ⁎ Corresponding author. Modern Evler Mah 142.Cadde, İksir Sitesi No 7/10 32100. Tel.: +90 5053912523; fax: +90 246 2237831. E-mail address: [email protected] (M. Karabacak). http://dx.doi.org/10.1016/j.ajem.2014.11.014 0735-6757/© 2014 Elsevier Inc. All rights reserved.
chemokines have been described in patients with essential HT and endothelial dysfunction [11]. Hypertensive crises are associated with increased cardiovascular mortality and morbidity [12] and characterized by severe HT [13]. They are divided depending on the presence of TOD [12,13]. There are numerous information on the contribution of inflammation to vascular damage in patients with HT [14-16]. However, the effect of vascular inflammation to the pathophysiology of HT crises is still unclear. Accordingly, we aimed to investigate the role of vascular inflammation in hypertensive crises and the relationship with the development of TOD. 2. Materials and methods 2.1. Patients and methods This study included 63 consecutive patients who presented to our emergency department with a diagnosis of hypertensive crisis between September 2013 and February 2014. The patients were categorized according to the presence of TOD. Thirty-three patients with TOD (15 female; mean age, 68 ± 12 y) and 30 patients without TOD (14 female; mean age, 64 ± 12 y) were enrolled. The control group consisted of 30 normotensive control patients (15 female; mean age, 65 ± 13 y). Hypertensive crisis was defined as systolic BP more than
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M. Karabacak et al. / American Journal of Emergency Medicine 33 (2015) 497–500
180 mm Hg and/or diastolic BP more than 120 mm Hg. Acute coronary syndrome (myocardial infarction with/without ST elevation, unstable angina pectoris), acute heart failure, acute pulmonary edema, cerebrovascular events (ischemic or hemorrhagic, transient ischemic attack), hypertensive encephalopathy, aortic dissection, hypertensive crises with retinopathy, microangiopathy, or acute renal failure were considered TOD. The systolic and diastolic BPs of the control group were less than 140/90 mm Hg. Exclusion criteria were any drug use that could potentially influence inflammatory conditions, hepatic dysfunction, hematologic disorders, history of malignancy, acute or chronic infection, and old stroke. Diabetes mellitus (DM) was defined as a fasting blood glucose level more than 126 mg/dL or use of antidiabetic drugs. Renal failure was defined as serum creatinine level more than 1.5 mg/dL in men and more than 1.4 mg/dL in women. The study was conducted in accordance with the guidelines proposed in the Declaration of Helsinki and approved by the local ethics committee. Informed consent was obtained from the parents of each subject.
Table 1 Demographic, clinical, and laboratory characteristics of TOD(+), TOD(−), and control groups
2.2. Measurement of BP
Abbreviations: BP1, before antihypertensive treatment; BP2, after antihypertensive treatment; CAD, chronic artery disease; CRF, chronic renal failure; BUN, blood urea nitrogen; AST, aspartate transaminase; ALT, alanine transaminase. P values represent the comparisons among 3 groups. ⁎ P b .01 vs control. ⁎⁎ P b .01 vs TOD(−).
In the emergency department, BP was measured with a mercury sphygmomanometer on the right arm; the first and fifth phases of Korotkoff sounds were used for systolic and diastolic BP, respectively. Three BP measurements were taken at 5-minute intervals by a physician with the patient in a seated position after at least a 5-minute rest, using an appropriately sized cuff. The mean of the 3 readings was considered the final BP value. 2.3. Biochemical measurements Blood samples were drawn from the antecubital vein by careful venipuncture into a sterile 21-gauge syringe without stasis. The samples were studied within 20 minutes, with the exception of whole blood count. The blood sampling and processing of samples were standardized. They were collected in dipotassium EDTA tubes and analyzed with the same automatic blood counter (Beckman Coulter Co, Miami, USA) within 5 minutes. To minimize degradation, the blood samples to determine MCP-1 levels were collected in ice-chilled disposable polypropylene tubes containing EDTA (1 mg/mL). The blood samples were rapidly separated by centrifugation in gel-containing vacuumed biochemistry tubes at 3000 rpm for 10 minutes, and the sera were stored in Eppendorf tubes (Eppendorf, Hamburg, Germany) at −80°C. 2.4. Measurement of MCP-1 levels Plasma MCP-1 levels were measured with the enzyme-linked immunosorbent assay (ELISA) method and determined using an ELISA kit (BMS281TEN; eBioscience, Vienna, Austria) according to the manufacturer’s protocols. The absorbance of the samples was measured at 450 nm using a Multiskan FC Microplate Photometer (Thermo Scientific Microplate Photometer, Multiskan FC, USA). The limit of detection was 2.31 pg/mL. The coefficient of interassay variation was 8.7%. 2.5. Statistical analysis Statistical analysis was performed using SPSS software, version 15 (SPSS, Chicago, IL). Distribution of continuous variables was tested by the Kolmogorov-Smirnov test. Continuous variables were expressed as mean ± SD or median and 25th to 75th percentile values as appropriate. Categorical variables were expressed as percentages. Statistical differences among groups were tested by one-way analysis of variance with post hoc Scheffé correction or Kruskal-Wallis test for parametric or nonparametric variables, respectively. The univariate linear regression model was used to adjust differences in MCP-1 for age and sex in the hypertensive crisis and control groups. Thereafter, linear regression analyses were performed stepwise to identify the possible association
Age, y Male/female, n/n Systolic BP1, mm Hg Diastolic BP1, mm Hg Systolic BP2, mm Hg Diastolic BP2, mm Hg HT, n (%) DM, n (%) CAD, n (%) CRF, n (%) BUN, mg/dL AST, U/L ALT, U/L Hemoglobin level, g/dL Platelet, ×103/mm3 MPV, fL
Control (n = 30)
TOD(−) (n = 30)
TOD(+) (n = 33)
P
65 ± 13 15/15 123 ± 7 76 ± 4 123 ± 7 76 ± 4 1 (3%) 0 (0%) 0 (0%) 0 (0%) 14 ± 4 19 ± 7 23 ± 7 14 ± 1.3 225 ± 79 8.4 ± 0.9
64 ± 12 16/14 209 ± 18⁎ 121 ± 6⁎ 160 ± 12⁎ 83 ± 9⁎ 21 (70%)⁎ 12 (40%)⁎
68 ± 12 18/15 213 ± 15⁎ 128 ± 13⁎,⁎⁎ 157 ± 12⁎ 82 ± 8⁎ 27 (82%)⁎ 16 (48%)⁎
4 (13%) 2 (6%) 19 ± 11 21 ± 5 20 ± 11 13.2 ± 1.8 257 ± 75 9.9 ± 1.2⁎
6 (20%) 3 (9%) 17 ± 6 24 ± 14 19 ± 7 13 ± 1.6 274 ± 76 10 ± 0.8⁎
.40 .82 b.001 b.001 b.001 b.001 b.01 b.01 .08 .26 .05 .07 .49 .14 .05 b.01
of MCP-1 as a dependent variable with potential confounding factors among the 3 groups. These confounders were systolic and diastolic BP before and after antihypertensive treatment, white blood cells (WBC), mean platelet volume (MPV), uric acid, C-reactive protein (CRP), high sensitive CRP, neutrophil counts, presence of DM, and HT. A P b .05 was considered statistically significant.
3. Results Baseline characteristics for all groups were presented in Table 1. Age and sex were comparable among the groups. Systolic and diastolic BP before and after antihypertensive treatment were higher in the hypertensive crisis groups compared with the control group (P b .01). Furthermore, diastolic BP before antihypertensive treatment was prominently higher in the patients with TOD (128 ± 13 mm Hg vs 121 ± 6 mm Hg vs 76 ± 4 mm Hg, respectively; P b .01). Presence of DM or HT was comparable in the groups with or without TOD. Mean platelet volume was higher in the hypertensive crises groups than in the control group. Neutrophil counts, WBC, high sensitive CRP, and uric acid levels were higher in the groups with or without TOD than in the control groups (Table 2). However, CRP (7.2 mg/dL [2-37.8 mg/dL] vs 4.6 mg/dL [1.5-14 mg/dL] vs 2.7 mg/dL [1-8.1 mg/dL]; P b .01) and MCP-1 levels (546 pg/mL [236-1350 pg/mL] vs 407 pg/mL [78-942 pg/mL] vs 264 pg/mL [34-579 pg/mL]; P b .01; Fig. 1) were higher in the group with TOD than other groups (Table 2). Table 2 Comparison of parameters associated with inflammation in TOD(+), TOD(−), and control groups
WBC, ×103/mL Neutrophils, ×103/mL Lymphocytes, ×103/mL NLR Uric acid, mg/dL Hs-CRP, mg/dL CRP, mg/dL MCP-1, pg/mL
Control (n = 30)
TOD(−) (n = 30)
TOD(+) (n = 33)
6.2 ± 1.4 3.60 ± 1.23 1.89 ± 0.34 2.01 ± 1.01 4.6 ± 1.3 1.3 (0.3-3.2) 2.7 (1-8) 264 (34-579)
8.5 ± 2.3⁎ 5.54 ± 1.69⁎ 2.40 ± 1.08 2.95 ± 2.00 6.5 ± 1.3⁎ 2.6 (1-5.5)⁎
8.8 ± 2.1⁎ 5.51 ± 2.09⁎ 2.25 ± 0.90 2.98 ± 2.01 7.2 ± 1.9⁎ 3.2 (1.5-6.3)⁎ 7.2 (2-38)⁎,⁎⁎
P
b.01 b.01 .17 .06 b.01 b.01 4.6 (2-14) b.01 407 (78-942) 546 (236-1350)⁎,⁎⁎ b.01
Abbreviations: NLR, neutrophil-lymphocyte ratio; Hs-CRP, high sensitive CRP. ⁎ P b .01 vs control. ⁎⁎ P b .01 vs TOD(−).
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Fig. 1. Monocyte chemoattractant protein-1 levels in hypertensive crises and control groups. Plasma MCP-1 levels are higher in patients with TOD than in the other groups (P b .001, unadjusted for age and sex).
Systolic and diastolic BP after and before antihypertensive treatment, MPV, WBC, neutrophil counts, CRP, high sensitive CRP, uric acid, and presence of DM or HT were different among the groups, and they were entered into linear regression in a stepwise method. Then, a multivariable analysis was performed among them to identify independent predictors associated with MCP-1. Among the univariate predictors, presence of DM (β = .563; 95% confidence interval [CI], 180.704363.684; P = .0001) and uric acid levels (β = .277; 95% CI, 10.19953.932; P = .005) were associated with plasma MCP-1 levels (Table 3). The relationship between plasma uric acid and MCP-1 levels was presented in Fig. 2. 4. Discussion Hypertensive crisis, associated with increased cardiovascular mortality and morbidity, is defined as a critical elevation of BP in which diastolic BP generally exceeds 120 mm Hg; it is traditionally divided depending on the presence of TOD and require early diagnosis and management to limit or prevent TOD, such as brain, kidney, heart, retina, and blood vessels [12,13]. The precise pathophysiology of hypertensive crisis is not well known. However, it is recognized that an individual is able to maintain organ perfusion with varying degrees of BP by autoregulatory mechanisms. According to 2 general theories, the pressure and humoral hypotheses, when a critical imbalance of pressure and/or humoral factors occurs, a series of pathologic events can lead to myointimal proliferation and fibrinoid necrosis [17]. This vascular damage can result in the deposition of platelets and fibrin as well as a breakdown of the normal autoregulatory function [18]. The numerous studies have demonstrated that vascular inflammation causes vascular damage and plays a key role in the pathogenesis and progression of atherosclerosis, cardiovascular disease, and HT [4-6,14-16]. At this point, chemokines play an important role in the control of vascular inflammation in the walls of blood vessels in HT [1]. Furthermore, the Table 3 The relationship of DM and uric acid levels on plasma MCP-1 levels Model
Presence of DM Uric acid
Unstandardized coefficients
Standardized coefficients
β
Std. error
β
95% CI
P
272.194 32.066
45.783 10.942
.563 .277
180.704-363.684 10.199-53.932
.000 .005
Abbreviation: Std., standard.
Fig. 2. Linear regression analysis of MCP-1 and uric acid levels in patients with hypertensive crisis. Uric acid level (β = .277; 95% CI, 10.199-53.932; P = .005) was dependently associated with plasma MCP-1 values.
inflammatory infiltrate in the vascular wall causes an increase in BP, and inhibition of these processes results in a decrease in BP [1]. They participate in the migration of leukocytes in the course of HT into the blood vessel wall [2,3]. Monocyte chemoattractant protein-1 contributes to the pathogenesis of atherosclerosis by promoting the recruitment of inflammatory cells to the vessel wall [7]. By activating the CCR2 receptor, it activates the recruitment of monocytes and leukocytes and migration to sites of vascular inflammation [8-10]. In some studies, elevated MCP-1 levels have been associated with an increased risk of death and recurrent ischemic events in acute coronary syndromes [19,20]. Moreover, a few years ago, elevated concentrations of MCP-1 with other chemokines have been described in patients with essential HT and endothelial dysfunction [11]. In another study, it has been shown that a lack of functional CCR2 receptors may be associated with the emergence of HT [21]. In experimental animals, several forms of HT induce infiltration of monocytes/macrophages into the vessel wall and in target organs, such as the kidney and the heart [15,16]. Moreover, hypertensive TOD is almost invariably accompanied by monocyte/macrophage infiltration into the involved organs [3]. Patients with elevated serum uric acid levels had a mean 10-fold increased risk of developing coronary artery disease or HT [22,23]. Hypertensive individuals with elevated serum uric acid levels had a significantly higher relative risk for both myocardial infarction and stroke [24]. These results strongly support the hypothesis that elevated serum uric acid level is an independent risk factor for HT-associated mortality and morbidity. In the present study, we found that uric acid levels were significantly higher independently of TOD in patients with hypertensive crises. Moreover, uric acid levels, in addition to the presence of DM, were positively associated with plasma MCP-1 levels (Fig. 2; Table 3). This result may be related with increased inflammation in hypertensive crises. Several studies show that higher levels of circulating CRP are related to higher BP [25-27]. Furthermore, tissue expression and plasma concentrations of inflammatory markers and chemokines such as CRP and MCP-1 are increased in experimental models of HT [28-30]. In addition, a recent study demonstrated that MCP-1 and CRP levels as inflammatory markers were higher in patients with HT. Moreover, this increase was correlated with systolic BP [31]. Similarly, in the present study, we found that CRP, high sensitive CRP, and MCP-1 levels were higher in the hypertensive crises group. Furthermore, CRP and MCP-1 levels were higher in the group with TOD than
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other groups. Unlikely, MCP-1 levels were associated with presence of DM and uric acid levels. 5. Study limitations Several limitations of this study should be considered. First, although there is no sample size was conducted, this study may be based on a relatively small sample size that has limited statistical power to detect small differences. Second, our analysis was based on a simple baseline determination at a single time point, which might not reflect patient status over long periods. 6. Conclusions In conclusion, plasma MCP-1 level was significantly higher in patients with hypertensive crises. More importantly, this elevation is more prominent in patients with TOD. In addition, MCP-1 levels were independently associated with uric acid and presence of DM. According to our results, we suggest that increased vascular inflammation and MCP-1 levels might be associated with the development of TOD in hypertensive crisis. References [1] Rodríguez-Iturbe B, Vaziri ND, Herrera-Acosta J, Johnson RJ. Oxidative stress, renal infiltration of immune cells and salt-sensitive hypertension: all for one and one for all. Am J Physiol 2004;286:606–16. [2] Johnson RJ, Alpers CE, Yoshimura A, Lombardi D, Pritzl P, Floege J, et al. Renal injury from angiotensin II-mediated hypertension. Hypertension 1992;19:464–74. [3] Haller H, Behrend M, Park JK, Schaberg T, Luft FC, Distler A. Monocyte infiltration and c-fms expression in hearts of spontaneously hypertensive rats. Hypertension 1995; 25:132–8. [4] Brasier AR, Recinos III A, Eledrisi MS. Vascular inflammation and the reninangiotensin system. Arterioscler Thromb Vasc Biol 2002;22:1257–66. [5] Schiffrin EL, Touyz RM. From bedside to bench to bedside: role of renin- angiotensinaldosterone system in remodeling of resistance arteries in hypertension. Am J Physiol Heart Circ Physiol 2004;287:H435–46. [6] Schiffrin EL. Vascular endothelin in hypertension. Vasc Pharmacol 2005;43:19–29. [7] Rossi D, Zlotnik A. The biology of chemokines and their receptors. Annu Rev Immunol 2000;18:217–42. [8] Charo IF, Ransohoff RM. The many roles of chemokines and chemokine receptors in inflammation. N Engl J Med 2006;354:610–21. [9] Bursill CA, Channon KM, Greaves DR. The role of chemokines in atherosclerosis: recent evidence from experimental models and population genetics. Curr Opin Lipidol 2004;15:145–9. [10] Boisvert WA. Modulation of atherogenesis by chemokines. Trends Cardiovasc Med 2004;14:161–5.
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