Abstract

Background:

Clinical studies have demonstrated that adipocytokines play an important role in developing atherosclerotic cardiovascular diseases.

Objective:

The aim of study was to evaluate the relationship between serum resistin and leptin levels with obesity and coronary artery disease (CAD).

Methods:

In a cross-sectional study, we assessed the levels of serum resistin and leptin, C-reactive protein (CRP), lipid profile and cardiac enzyme tests (AST, CPK, LDH, CK-MB) in 40 CAD patients compared to 40 healthy controls. Anthropometric measurements including weight and height for calculating of body mass index (BMI), and waist circumference (WC) were performed for evaluation of obesity.

Results:

CAD patients had increased levels of leptin and CRP, (p < 0.001), cholesterol (p < 0.05), triglyceride (p < 0.01), and WC (p < 0.05) compared to healthy controls. There was no statistical difference between CAD and control subjects for resistin (p = 0.058). In a multiple regression analysis, only an association between serum leptin with BMI (β = 0.480, p < 0.05) and WC (β = 1.386, p < 0.05) was found.

Conclusions:

The findings suggest that leptin is a better marker of fat mass value than resistin and may be considered an independent risk factor for cardiac disorders that is largely dependent on obesity. However, further prospective studies are needed to confirm these results.

Keywords:
Coronary Artery Disease; Obesity; Resistin; Leptin; Atherosclerosis

Resumo

Fundamento:

Estudos clínicos demonstraram que adipocitocinas têm papel importante no desenvolvimento de doenças cardiovasculares ateroscleróticas.

Objetivo:

Avaliar a relação entre níveis de leptina e resistina em soro com obesidade e doença arterial coronariana (DAC).

Métodos:

Em estudo transversal, avaliamos os níveis de resistina e leptina em soro, proteína C-reativa (CPR), perfil lipídico e testes de enzimas cardíacas (AST, CPK, LDH, CK-MB) em quarenta pacientes com DAC comparados a 40 controles saudáveis. Para avaliação de obesidade, foram feitas as medições antropométricas, incluindo peso e altura para o cálculo do índice de massa corporal (IMC) e circunferência da cintura (CC).

Resultados:

Pacientes com DAC apresentaram aumento nos níveis de leptina e CPR, (p < 0,001), colesterol (p < 0,05), triglicérides (p < 0,01) e CC (p < 0,05) em comparação aos controles. Não houve diferença significativa entre DAC e controles com relação à resistina (p = 0,058). Na análise de regressão múltipla, foi encontrada apenas uma associação entre leptina em soro ao IMC (β = 0,480, p < 0,05) e CC (β = 1,386, p < 0,05).

Conclusões:

Os achados sugerem que a leptina é melhor marcadora de valor de massa gorda do que a resistina, e pode ser considerada um fator de risco, dependente da obesidade, independente para distúrbios cardíacos. Contudo, outros estudos prospectivos serão necessários para a confirmação desses resultados.

Palavras-chave:
Doença Arterial Coronariana; Obesidade; Resistina; Leptina; Aterosclerose

Introduction

Obesity and coronary artery disease (CAD) are the most important health problems worldwide, especially in the adult Iranian population.¹1 EbrahimiM, Kazemi-BajestaniSMR, Ghayour-MobarhanM , FernsGAA. Coronary artery disease and its risk factors status in Iran: a review. Iran Red Crescent Med J. 2011;13(9):610-23.

2 Adel SM, Ramezanei AA, Hydarei A, Javaherizadeh H, Behmanesh V, Amanei V. Gender-related differences of risk factors among patients undergoing coronary artery bypass graft in Ahwaz, Iran. Saudi Med J. 2007;28(11):1686-9.^-33 Maddah M, Chinikar M, Hoda S. Iranian women with coronary artery disease: not behind of the men. Int J Cardiol. 2007;115(1):103-4. CAD is one of the major atherosclerotic manifestations, and is associated with clinical demonstrations of acute coronary syndrome including angina and myocardial infarction.¹1 EbrahimiM, Kazemi-BajestaniSMR, Ghayour-MobarhanM , FernsGAA. Coronary artery disease and its risk factors status in Iran: a review. Iran Red Crescent Med J. 2011;13(9):610-23. Obesity, the most important nutritional disorder in industrialized countries, is a prominent risk factor for CAD.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.

5 Yusuf S, Hawken S, Ounpuu S, Bautista L, Franzosi MG, Commerford P, et al. Obesity and the risk of myocardial infarction in 27,000 participants from 52 countries: a case-control study. Lancet. 2005;366(9497):1640-9.^-66 Yañez-Rivera TG, Baños-Gonzalez MA, Ble-Castillo JL, Torres-Hernandez ME, Torres-Lopez, J E, Borrayo-Sanchez G. Relationship between epicardial adipose tissue, coronary artery disease and adiponectin in a Mexican population. Cardiovasc Ultrasound. 2014;12:35 Evidence shows that some forms of obesity, particularly elevated abdominal adiposity, might be responsible for metabolic disorders and vascular diseases.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,77 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,88 Cirillo P, Maresca F, Di Palma V, Ziviello F, Bevilacqua M. Adipose tissue in the pathophysiology of cardiovascular disease: Who is guilty? World J Hypertens. 2012;2(1):13-21. The distribution of regional fat, especially the amount of visceral fat around the heart, may affect coronary arteries and the myocardium,⁹9 Baker AR, da Silva NF, Quinn DW, Harte L, Pagano D, Bonser RS, et al. Human epicardial adipose tissue expresses a pathogenic profile of adipocytokines in patients with cardiovascular disease. Cardiovasc Diabetol. 2006;13(5):1 which may be considered a predictive factor for cardiovascular risk.¹⁰10 Laughlin GA, Barrett-Connor E, May S, Langenberg C. Association of adiponectin with coronary heart disease and mortality: the Rancho Bernardo study. Am J Epidemiol. 2007;165(2):164-74.

Clinical studies have demonstrated that apart from classic risk factors such as hypertension, dyslipidaemia, and insulin resistance,¹¹11 Reilly MP, Iqbal N, Schutta M, Wolfe ML, Scally M, Localio AR, et al. Plasma leptin levels are associated with coronary atherosclerosis in type 2 diabetes. J Clin Endocrinol Metab.2004;89(8):3872-8. adipocytokines also play an important role in developing atherosclerotic cardiovascular diseases.¹1 EbrahimiM, Kazemi-BajestaniSMR, Ghayour-MobarhanM , FernsGAA. Coronary artery disease and its risk factors status in Iran: a review. Iran Red Crescent Med J. 2011;13(9):610-23.^,77 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,1111 Reilly MP, Iqbal N, Schutta M, Wolfe ML, Scally M, Localio AR, et al. Plasma leptin levels are associated with coronary atherosclerosis in type 2 diabetes. J Clin Endocrinol Metab.2004;89(8):3872-8. Adipose tissue, abundantly represented in obese rodents and humans, secretes some hormones, peptides, and other molecules that may potentially act as pro-atherogenic markers.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,88 Cirillo P, Maresca F, Di Palma V, Ziviello F, Bevilacqua M. Adipose tissue in the pathophysiology of cardiovascular disease: Who is guilty? World J Hypertens. 2012;2(1):13-21.^,99 Baker AR, da Silva NF, Quinn DW, Harte L, Pagano D, Bonser RS, et al. Human epicardial adipose tissue expresses a pathogenic profile of adipocytokines in patients with cardiovascular disease. Cardiovasc Diabetol. 2006;13(5):1^,1212 Schwartz DR , Lazar MA .Human resistin: found in translation from mouse to man. Trends Endocrinol Metab. 2011;22(7):259-65. Resistin and leptin, vasoactive substances produced by adipocytes, are potential mediators,⁷7 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,1212 Schwartz DR , Lazar MA .Human resistin: found in translation from mouse to man. Trends Endocrinol Metab. 2011;22(7):259-65.

13 Singh M, Bedi US, Singh PP, Arora SR, Khosla S. Leptin and the clinical cardiovascular risk. Int J Cardiol. 2010;140(3):266-71.^-1414 Qasim A, Mehta NN, Tadesse MG, Wolfe ML, Rhodes T, Girman C, et al. Adipokines, insulin resistance and coronary artery calcification. J Am Coll Cardiol. 2008;52(3):231-6. which contribute to the inflammatory processes related to obesity in both vascular and non-vascular tissues,⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,1515 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75.^,1616 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5. and activate endothelial cells.¹⁵15 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75.^,1717 Mohammadzadeh G, Zarghami N, Mobaseri M. Serum resistin concentration in obese diabetic patients: any possible relation to insulin resistance indices? Int J Endocrinol Metab. 2008;4:183-93.^,1818 Yaturu S, Daberry RP, Rains J, Jain S. Resistin and adiponectin levels in subjects with coronary artery disease and type 2 diabetes. Cytokine. 2006;34(3-4):219-23. Because of these properties, resistin and leptin have been hypothesized to be a causal factor in the development of cardiovascular diseases, especially atherosclerotic coronary artery disease and congestive heart failure (CHD).¹⁴14 Qasim A, Mehta NN, Tadesse MG, Wolfe ML, Rhodes T, Girman C, et al. Adipokines, insulin resistance and coronary artery calcification. J Am Coll Cardiol. 2008;52(3):231-6.^,1616 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5. Studies on adipokines and obesity have shown that elevated levels of resistin¹⁹19 Muse ED, Blaha M J, Tota-Maharaj R, Budoff MJ, Nasir K, Criqui MH, et al.. The association of human resistin and cardiovascular disease in multi-ethnics study of atherosclerosis (MESA). J Am Coll Cardiol.2013;61(10_S)^,2020 Zhang JL, Qin YW, Zheng X, Qiu JL, Zou DJ . Serum resistin level in essential hypertension patients with different glucose tolerance. Diabet Med.2003;20(10):828-31. and leptin¹⁴14 Qasim A, Mehta NN, Tadesse MG, Wolfe ML, Rhodes T, Girman C, et al. Adipokines, insulin resistance and coronary artery calcification. J Am Coll Cardiol. 2008;52(3):231-6.^,2121 Reilly MP, Lehrke M, Wolfe ML, Rohatgi A, Lazar MA, Rader DJ. Resistin is an inflammatory marker of atherosclerosis in humans. Circulation. 2005; 111(7):932-9.

22 Myers MG, Leibel RL, Seeley RJ, Schwartz MW .Obesity and leptin resistance: distinguishing cause from effect. Trends Endocrinol Metab. 201021(11):643-51.

23 Karbowska J, Kochan Z. Leptin as a mediator between obesity and cardiac dysfunction. Postepy Hig Med Dosw/online. 2012;66:267-74.^-2424 Akram S, Ahmed Z, Fayyaz I, Mehmood S, Ghani M, Choudhary AM, et al..Serum leptin levels in patients with coronary artery disease. J Ayub Med Coll Abbottabad. 2011; 23(4):13-4. are linked to increased body mass index (BMI), and their receptors are increased in abdominal fat depots.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918. Due to the high prevalence of CAD, the evaluation of serum levels of adipokines may be used as a prognostic marker in screening, diagnosing and predicting atherosclerosis. Thus, we designed this study to investigate the relationship between changes in resistin and leptin levels with obesity and CAD.

Methods

Study patients

In a case-control study, forty patients aged 30-80 years old (mean age of 55.6 ±13.4 yr; BMI of 25 ± 4.8 kg/m²) admitted to the cardiology section of Emam Ali hospital of Zahedan , Iran, who had 50% or more coronary stenosis in at least one major coronary artery were enrolled in the CAD group. Exclusion criteria included medical history (e.g., diabetes mellitus, thyroid , liver or renal failure , cardiomyopathy, left ventricular systolic dysfunction or severe heart failure, acute or chronic inflammatory disorders, or the recent use of lipid-lowering drugs and corticosteroids or smoking). After matching for age and sex, 40 healthy volunteers aged 30-79 years old (mean age of 53 ±12 yr; BMI of 25.7± 4.9 kg/m²) without cardiovascular and any organ system disease and on no medications were selected as the control group. The study was performed between June and December of 2014.

Methodology

A demographic questionnaire, including age, sex, BMI, waist circumference (WC), medical history including smoking habit, presence of hypertension, hyperlipidemia and current medications was filled out by all subjects. Simple anthropometric measurements including weight and height to calculate BMI, and WC were performed for evaluation of obesity.²⁵25 Mahan LK, Escott-Stump S, Raymond JL. Krause's food and the nutrition care process . 13th ed. Philadelphia: WB Saunders; 2012. (Krause's Food &Nutrition Therapy) The measurements of weight and height were performed with light clothing and without shoes, and approximated to the nearest 0.5 kg and 0.5 cm, respectively. The WC was measured with a non-stretchable standard tape, at the narrowest point between the costal margin and iliac crest. BMI ≥ 25 kg/m² (general obesity), and WC > 102 cm in men and > 88 cm in women (abdominal obesity) were considered risk factors for cardiovascular disease.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,2525 Mahan LK, Escott-Stump S, Raymond JL. Krause's food and the nutrition care process . 13th ed. Philadelphia: WB Saunders; 2012. (Krause's Food &Nutrition Therapy)

Blood samples were taken after a 12-hour overnight fast. Biochemical parameters including serum cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), creatine phosphokinas (CPK), lactate dehydrogenase (LDH), creatine kinase (CK-MB), and aspartate transaminase (AST) levels were measured by commercial kits (Pars azmun ,Tehran, Iran) using an auto-analyzer (Hitachi , Japan). Serum high-sensitivity C-reactive protein (hs-CRP) levels were assessed by latex- enhanced nephelometry (Behring BN II nephelometer, Germany).

Levels of serum resistin and leptin were measured by enzyme-linked immune-sorbent assay (ELISA) with commercial kits: [HUMAN resistin ELISA kit (Cat.No:EK0581; Boster biological technology; 40459 Encyclopedia Circle, Fermont, CA 94538, USA], and [HUMAN leptin ELISA kit (Cat. No: RD 191001100, USA).The serum samples were immediately frozen at -70ºC until analysis.

The study was approved by the ethics committee of (omitted to the review process) and informed consent was obtained from all subjects. (Approval date: 21 April 2014; Code No: 6696).

Statistical analysis

The analysis was performed by SPSS statistical software package program (version 18 for windows, Chicago, USA). Data were tested for normal distribution using the Kolmogorov- Smirnov test. Data were expressed as mean ± SD or mean ± SEM in accordance with their distribution. Variables with normal distribution were compared by unpaired Student's t-test and one-way ANOVA. Mann-Whitney U test was performed for non-normal distribution variables. Resistin and leptin values were compared using multivariable regression analysis, adjusted for age and sex. P value < 0.05 was considered significant.

Results

Demographic and chemical characteristics of subjects have been summarized in Table 1. Age, BMI, LDL and HDL levels were not significantly different between patients and controls. The mean WC (p < 0.05), serum cholesterol (p < 0.05), triglyceride (p < 0.01) and hs-CRP (p < 0.001) levels were markedly increased when compared to healthy controls.

Compared to the controls, serum levels of leptin were significantly higher in CAD patients (p < 0.001). Serum resistin levels differed between two groups, but this difference was not significant (p = 0.058).

As shown in Figures1 and 2, a positive correlations between resistin and BMI (r = 0.56, p < 0.0001) and WC (r = 0.55, p < 0.0001), and between leptin with BMI (r = 0.57, p < 0.0001) and WC (r = 0.48, p < 0.001) were found.

In multiple regression analysis, leptin was associated with BMI ((β = 0.480, p < 0.05) and WC (β = 1.386, p < 0.05) in CAD patients, but this association was not significant for resistin.

Discussion

The present study evaluated the relationship between resistin and leptin levels with obesity and some risk factors of CAD. We demonstrated that the serum resistin concentration differed between CAD patients and the control group, but this difference was not significant, confirming results of previous studies.¹⁸18 Yaturu S, Daberry RP, Rains J, Jain S. Resistin and adiponectin levels in subjects with coronary artery disease and type 2 diabetes. Cytokine. 2006;34(3-4):219-23.^,2525 Mahan LK, Escott-Stump S, Raymond JL. Krause's food and the nutrition care process . 13th ed. Philadelphia: WB Saunders; 2012. (Krause's Food &Nutrition Therapy) Several studies have reported serum resistin levels to be significantly elevated in CAD patients.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,1919 Muse ED, Blaha M J, Tota-Maharaj R, Budoff MJ, Nasir K, Criqui MH, et al.. The association of human resistin and cardiovascular disease in multi-ethnics study of atherosclerosis (MESA). J Am Coll Cardiol.2013;61(10_S)^,2626 Azuma K, Katsukawa F, Oguchi S,Murata M, Yamazaki H, Shimada A. Correlation between serum resistin level and adiposity in obese individuals. Obes Res. 2003;11(8): 997-1001.^,2727 Ohmori R, Momiyama Y , Kato R , Taniguchi H , Ogura M , Ayaori M , et al. Associations between serum resistin levels and insulin resistance, inflammation,and coronary artery disease. J Am Coll Cardiol. 2005;46(2):379-82. In contrast, other studies¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,2828 Sinan UY, Canbolat IP, Baydar O, Oktay V, Imre G, Kocas C, et al. Relationship between increased serum resistin level and severity of coronary artery disease. Angiology. 2014; 65(3):239-42. found no such correlation. In clinical and experimental studies, resistin has been suggested to be an independent inflammatory marker in cardiovascular diseases, especially in CAD and heart failure.¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,2828 Sinan UY, Canbolat IP, Baydar O, Oktay V, Imre G, Kocas C, et al. Relationship between increased serum resistin level and severity of coronary artery disease. Angiology. 2014; 65(3):239-42.

29 Steppan CM, Bailey ST, Bhat S, Brown EJ, Banerjee RR, Wright CM, et al. The hormone resistin links obesity to diabetes. Nature.2001;409(6818):307-12.^-3030 Kusminski CM, da Silva NF, Creely SJ, Fisher FM, Harte AL, Baker AR, et al. The in vitro effects of resistin on the innate immune signaling pathway in Isolated human subcutaneous adipocytes. J Clin Endocrinol Metab. 2007; 92 (1): 270-6

High serum leptin levels observed in patients with CAD in our study were consistent with earlier studies,²²22 Myers MG, Leibel RL, Seeley RJ, Schwartz MW .Obesity and leptin resistance: distinguishing cause from effect. Trends Endocrinol Metab. 201021(11):643-51.^,3131 Lee SE, Kim HS. Human resistin in cardiovascular disease. J Smooth Muscle Res. 2012;48(1):27-35.^,3232 Wallace AM, McMahon AD, Packard CJ, Kelly A, Shepherd J, Gaw A, et al. Plasma leptin and the risk of cardiovascular disease in the west of Scotland coronary prevention study (WOSCOPS). Circulation. 2001;104(25):3052-6. suggesting the role of this hormone as a mediator in human atherosclerotic. By contrast, some data indicate that leptin may protect against atherosclerosis in specific animal models,³³33 Koh KK, Park SM, Quon MJ. Leptin and cardiovascular disease: response to therapeutic interventions . Circulation. 2008;117(25):3238-49. and a study¹⁵15 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75. found no significant difference between CHD patients and controls.

Regarding BMI and WC findings, although BMI is recognized as a gold standard indicator for evaluation of obesity,⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,3434 Ouchi N, Kihara S, Funahashi T, Nakamura T, Nishida M, Kumada M, et al. Reciprocal association of C-reactive protein with adiponectin in blood stream and adipose tissue. Circulation. 2003;107(5):671-4. it is not always a reliable measurement of body composition, because it cannot show the regional distribution of body fat. In fact, people with similar body mass indexes may have different amounts of fat in the bodies. Thus, WC was measured to determine visceral fat accumulation, and as an indicator of health risks associated with central obesity.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918. Recent studies suggest that the central (abdominal, visceral) distribution of fat, particularly abdominal fat accumulation, which is a source of pro-inflammatory adipokines, has a more important role in the determination of risk.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,77 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,88 Cirillo P, Maresca F, Di Palma V, Ziviello F, Bevilacqua M. Adipose tissue in the pathophysiology of cardiovascular disease: Who is guilty? World J Hypertens. 2012;2(1):13-21. In the present study, after adjustment for sex, age, BMI and WC, obese patients with elevated BMI showed higher serum leptin levels compared to non-obese patients, but this difference was not significant when compared to the control group for resistin levels (data not shown). As well, resistin and leptin levels were significantly higher in abdominal obese patients than in patients without abdominal obesity or in the control group. Moreover, in multivariate regression analysis, we found an association between serum leptin with BMI and WC after adjusting of age and sex, but this association was not significant for resistin. Our findings were partly consistent with earlier reports,¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,1919 Muse ED, Blaha M J, Tota-Maharaj R, Budoff MJ, Nasir K, Criqui MH, et al.. The association of human resistin and cardiovascular disease in multi-ethnics study of atherosclerosis (MESA). J Am Coll Cardiol.2013;61(10_S)^,2929 Steppan CM, Bailey ST, Bhat S, Brown EJ, Banerjee RR, Wright CM, et al. The hormone resistin links obesity to diabetes. Nature.2001;409(6818):307-12. but not with some studies.²¹21 Reilly MP, Lehrke M, Wolfe ML, Rohatgi A, Lazar MA, Rader DJ. Resistin is an inflammatory marker of atherosclerosis in humans. Circulation. 2005; 111(7):932-9.^,2626 Azuma K, Katsukawa F, Oguchi S,Murata M, Yamazaki H, Shimada A. Correlation between serum resistin level and adiposity in obese individuals. Obes Res. 2003;11(8): 997-1001. It is worth noting that human resistin is more predominantly expressed in macrophages than adipocytes.¹²12 Schwartz DR , Lazar MA .Human resistin: found in translation from mouse to man. Trends Endocrinol Metab. 2011;22(7):259-65. Our findings suggest that leptin is a better marker of fat mass values.

Obesity is also linked to with several established risk factors of cardiovascular disease.⁷7 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,88 Cirillo P, Maresca F, Di Palma V, Ziviello F, Bevilacqua M. Adipose tissue in the pathophysiology of cardiovascular disease: Who is guilty? World J Hypertens. 2012;2(1):13-21. Dyslipidemia is one of the most prevalent of CVD risk factors in obesity, especially in abdominal obesity.³⁵35 Piestrzeniewicz K, Luczak K, Komorowski J, Maciejewski M, Jankiewicz Wika J, Goch JH. Resistin increases with obesity and atherosclerotic risk factors in patients with myocardial infarction. Metabolism. 2008;57(4):488-93. Several investigations have reported that dyslipidemia is one of the strongest factors independently associated with CAD in the Iranian population.¹1 EbrahimiM, Kazemi-BajestaniSMR, Ghayour-MobarhanM , FernsGAA. Coronary artery disease and its risk factors status in Iran: a review. Iran Red Crescent Med J. 2011;13(9):610-23.

2 Adel SM, Ramezanei AA, Hydarei A, Javaherizadeh H, Behmanesh V, Amanei V. Gender-related differences of risk factors among patients undergoing coronary artery bypass graft in Ahwaz, Iran. Saudi Med J. 2007;28(11):1686-9.^-33 Maddah M, Chinikar M, Hoda S. Iranian women with coronary artery disease: not behind of the men. Int J Cardiol. 2007;115(1):103-4.^,3636 Després JP, Lemieux I. Abdominal obesity and metabolic syndrome. Nature. 2006;444(7121):881-7. When lipids accumulate within the cells of the arterial wall, it leads to systemic inflammation and atherosclerosis.⁴4 Wang Z, Nakayama T. Inflammation, a link between obesity and cardiovascular disease. Mediators Inflamm. 2010;2010:535918.^,3737 Menzaghi C , Bacci S, Salvemini L, Mendonca C, Palladino G, Fontana A, et al. Serum resistin, cardiovascular disease and all-cause mortality in patients with type 2 diabetes. Plos One. 2013;8(6):e64729. In this study, we found no significant correlation between resistin and leptin with lipid profile, supporting results of other studies.¹⁵15 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75.^,1717 Mohammadzadeh G, Zarghami N, Mobaseri M. Serum resistin concentration in obese diabetic patients: any possible relation to insulin resistance indices? Int J Endocrinol Metab. 2008;4:183-93. In some studies, a significant positive association between serum resistin¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,3838 Ebrahimi M, Kazemi-Bajestani SM, Ghayour-Mobarhan M, Moohebati M, Paydar R, Azimi-Nezhad M, et al. Metabolic syndrome may not be a good predictor of coronary artery disease in the Iranian population: population-specific definitions are required. Scientific WorldJournal. 2009;9:86-96. and leptin¹⁵15 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75. with triglyceride and cholesterol levels has been revealed. The reasons for inconsistencies between our findings and other studies may be explained by the study design and sample size.

It has been recently suggested that obesity is related to subclinical inflammation, as reflected by increased CRP levels.²⁶26 Azuma K, Katsukawa F, Oguchi S,Murata M, Yamazaki H, Shimada A. Correlation between serum resistin level and adiposity in obese individuals. Obes Res. 2003;11(8): 997-1001.^,3939 Rajala MW, Scherer P E. Minireview: the adipocyte-at the crossroads of energy homeostasis, inflammation, and atherosclerosis. Endocrinology.2003;144(9):3765-73.^,4040 Martin SS, Qasim AN, Rader DJ, Reilly MP . C-reactive protein modifies the association of plasma leptin with coronary calcium in asymptomatic overweight individuals. Obesity. 2012;20(4):856-61. Evidence shows that resistin and leptin levels with inflammatory activity might play an important role in the development of inflammatory mechanisms and promote the progression of atherosclerotic disease.⁷7 Rashid SH. Mechanisms by which elevated resistin levels accelerate atherosclerotic cardiovascular disease. Rheumatol Curr Res. 2013;3(1):1-6.^,1414 Qasim A, Mehta NN, Tadesse MG, Wolfe ML, Rhodes T, Girman C, et al. Adipokines, insulin resistance and coronary artery calcification. J Am Coll Cardiol. 2008;52(3):231-6.^,1616 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,2020 Zhang JL, Qin YW, Zheng X, Qiu JL, Zou DJ . Serum resistin level in essential hypertension patients with different glucose tolerance. Diabet Med.2003;20(10):828-31.^,3939 Rajala MW, Scherer P E. Minireview: the adipocyte-at the crossroads of energy homeostasis, inflammation, and atherosclerosis. Endocrinology.2003;144(9):3765-73. CRP is one of the best standardized markers for prediction of systemic inflammation degree.¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,4040 Martin SS, Qasim AN, Rader DJ, Reilly MP . C-reactive protein modifies the association of plasma leptin with coronary calcium in asymptomatic overweight individuals. Obesity. 2012;20(4):856-61. Resistin¹⁶16 Zheng H , Xu H, Xie N, Huang J, Fang H, Luo M . Association of serum resistin with peripheral arterial disease. Pol Arch Med Wewn. 2013;123(12):680-5.^,2020 Zhang JL, Qin YW, Zheng X, Qiu JL, Zou DJ . Serum resistin level in essential hypertension patients with different glucose tolerance. Diabet Med.2003;20(10):828-31.^,2626 Azuma K, Katsukawa F, Oguchi S,Murata M, Yamazaki H, Shimada A. Correlation between serum resistin level and adiposity in obese individuals. Obes Res. 2003;11(8): 997-1001. and leptin¹⁵15 Sattar N, Wannamethee G, Sarwar N, Chernova J, Lawlor DA, Kelly A, et al. Leptin and coronary heart disease : prospective study and systematic review. J Am Coll Cardiol.2009;53(2):167-75.^,3939 Rajala MW, Scherer P E. Minireview: the adipocyte-at the crossroads of energy homeostasis, inflammation, and atherosclerosis. Endocrinology.2003;144(9):3765-73. stimulate the production of CRP in coronary endothelial cells, and CRP induces vascular thrombosis that might be involved in the pathophysiology of acute coronary syndromes. In our study, no correlation of CRP was present in CAD patients with resistin and leptin, BMI and WC, suggesting that leptin and resistin are linked to CAD risk regardless of CRP.

Our study had several limitations, including a relatively small sample size. Because of the high cost of resisitin and leptin kits, only 80 subjects (patients and healthy volunteers) were enrolled in our study. Moreover, it was a cross-sectional design and did not prove causation. Therefore, the generalizability of our findings across social and ethnic groups is unknown.

Conclusion

The study indicated that circulating leptin levels, but not resistin levels, were higher in CAD patients in comparison to controls. As well, in the multivariate regression analysis, after adjusting of age and sex, only an association between serum leptin with BMI and WC was found. It suggests that leptin is a better marker of fat mass value than resistin and may be considered an independent risk factor for cardiac disorders that is largely dependent on obesity. However, further prospective studies are needed to confirm these results.

Acknowledgment

The authors gratefully acknowledge Dr. Ali-Reza Dashipour for his assistance in statistical analyses. We also thank the nurses of the CCU section in Zahedan Emam Ali Hospital for their kind cooperation.

References

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