Clinical Endocrinology (2012) 77, 47–50
doi: 10.1111/j.1365-2265.2011.04217.x
ORIGINAL ARTICLE
Chemerin levels are positively correlated with abdominal visceral fat accumulation Hyun-Young Shin*, Duk C. Lee*, Sang H. Chu†, Justin Y. Jeon‡, Mi K. Lee‡, Jee A. Im§ and Ji W. Lee* *Department of Family Medicine, Severance Hospital, Yonsei University College of Medicine, †Department of Clinical Nursing Science, Yonsei University College of Nursing, ‡Department of Sport and Leisure Studies, Yonsei University and §Sport and Medicine Research Center, INTOTO Inc., Seoul, Korea
Summary Objective Chemerin, a recently discovered adipocytokine, may be linked to obesity and obesity-associated metabolic complications. However, the relationship between visceral fat accumulation and chemerin is still unknown. Therefore, we investigated the relationship between serum chemerin levels and body composition as measured by computed tomography (CT). Patients We recruited 173 men and women without histories of diabetes or cardiovascular disease. Measurements Biomarkers of metabolic risk factors and body composition by computed tomography were assessed. Serum chemerin levels were measured by enzyme-linked immunosorbent assay. Results Chemerin levels correlated with body mass index (BMI), waist circumference, abdominal visceral fat area, blood pressure, fasting insulin, homoeostasis model of assessment-insulin resistance, total cholesterol, triglyceride, creatinine, aspartate aminotransferase and alanine aminotransferase. By stepwise multiple regression analysis, abdominal visceral fat area, blood pressure and total cholesterol levels independently affected chemerin levels. Conclusions Abdominal visceral fat accumulation, blood pressure and lipid profile were significantly associated with serum chemerin levels. Our findings suggest that chemerin may be a mediator that links visceral obesity to cardiovascular risk factors. (Received 15 July 2011; returned for revision 3 August 2011; finally revised 18 August 2011; accepted 26 August 2011)
Introduction Visceral fat has a stronger association with cardiometabolic risk than subcutaneous fat.1 Although the pathological mechanisms
Correspondence: Ji Won Lee, Department of Family Medicine, Severance Hospital, Yonsei University College of Medicine, 50,Yonsei-ro, Seodaemun-Gu, Seoul 120-752, Korea. Tel.: 82-2-2228-2338; Fax: 82-2-362-2473; E-mail:
[email protected] Ó 2012 Blackwell Publishing Ltd
linking visceral fat with these co-morbidities are multifactorial, increasing evidence indicates that altered secretion of adipokines is a contributing factor.2 Chemerin is a newly discovered adipokine that regulates adipocyte development and metabolic function as well as immune function.3,4 Recent studies have demonstrated that chemerin induces insulin resistance in adipocytes and skeletal muscle cells in vitro5 and that chemerin levels in humans are associated with multiple components of the metabolic syndrome including body mass index (BMI),triglycerides, high-density lipoprotein (HDL)cholesterol and hypertension.6 These findings suggest that chemerin may play a role in the pathophysiology of obesity, especially visceral obesity. However, to date, only a few clinical studies have investigated the relationship between serum chemerin levels and body composition. Furthermore, in previous studies,6,7 adiposity was not measured using accurate methods. Therefore, we investigated the relationship between serum chemerin levels and body composition including abdominal adiposity as measured by computed tomography (CT).
Subject and methods We recruited 173 healthy subjects who visited the Family Medicine and Health Promotion Center at Severance Hospital. All the participants provided written informed consent, and the study protocol was approved by the Institutional Review Board of Severance Hospital. None of the subjects had a previous diagnosis or evidence of cardiovascular disease, diabetes, moderate to severe hypertension [resting blood pressure (BP) >170/100 mmHg], dyslipidaemia, body weight fluctuation of 5 kg in the recent 6 months, acute infectious disease or chronic inflammatory disease. In addition, we excluded pregnant women and subjects who had chronic renal disease, endocrine disease, cancer or medication usage that could affect cardiometabolic function. All subjects completed a lifestyle questionnaire that included cigarette smoking and alcohol consumption. BMI was calculated by dividing weight by height squared (kg/m2). We measured waist circumference at the midpoint between the lower border of the rib cage and the iliac crest. Abdominal adipose tissue areas were
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quantified by CT (Tomoscan 350; Philips, Mahwah, NJ, USA) as described previously.8 Blood samples were collected in the morning between 0800 and 1100 h after overnight fasting. We measured fasting glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, total cholesterol, triglyceride and HDL-cholesterol levels using an ADVIA 1650 chemistry system (Bayer, Terrytown, NY, USA). LDL-cholesterol levels were calculated using the Friedewald equation. Fasting insulin was measured by a chemiluminescence immunoassay (Roche, IN, USA). Insulin resistance was calculated using the homoeostasis model assessment of insulin resistance (HOMA-IR) index [fasting insulin (units per millilitre) * fasting glucose (millimolar)/22Æ5]. Levels of high-sensitivity C-reactive protein (hsCRP) were measured by a latex-enhanced immunoturbidimetric assay using an ADVIA 1650 Chemistry system (Bayer); the interassay and intra-assay reproducibilities of this assay were 2Æ70 ± 1Æ13% and 2Æ55 ± 1Æ0%, respectively. Chemerin levels were measured with an enzyme immunoassay kit (Mesdia, Seoul, Korea) with an interassay and intra-assay variability of 11Æ3 ± 6Æ0% and
8Æ4 ± 3Æ7%, respectively. We analysed all data using the statistical program sas 9.1 (SAS Institute, Cary, NC, USA). After adjusting for age, gender and BMI, Pearson’s and Spearman’s correlation coefficients with a Bonferroni correction were calculated to evaluate the relationship between serum chemerin levels and metabolic risk factors. A stepwise multiple linear regression analysis was used to clarify the factors contributing to serum chemerin levels. Significance was defined as P < 0Æ05.
Results A total of 173 subjects (79 men and 94 women; mean age, 32Æ51 ± 9Æ25 years) participated in the study. Chemerin levels showed significant positive correlation with BMI, waist circumference, abdominal visceral fat area, systolic BP, diastolic BP, fasting insulin, HOMA-IR, total cholesterol, triglyceride, creatinine, AST and ALT. After adjusting for age, gender and BMI, chemerin levels correlated with abdominal visceral fat area, diastolic BP and total cholesterol as shown in Table 1 and Fig. 1.
Table 1. Clinical characteristics of the study subjects and the correlation between body composition, metabolic variables and chemerin levels Age, sex adjusted
Unadjusted Total (n = 173) Age (years) Male (number/%) Adiposity index BMI (kg/m2) Waist (cm) Visceral fat area (cm2) Subcutaneous fat area (cm2) Metabolic variables Systolic BP (mmHg) Diastolic BP (mmHg) Fasting glucose (mm) Fasting insulin (pm) HOMA-IR Total cholesterol (mm) Triglyceride (mm) HDL-cholesterol (mm) LDL-cholesterol (mm) Creatinine (lm) AST (U/l) ALT (U/l) hsCRP (mg/l) Smoking status (number/%) Nonsmokers Former smokers Current smokers Alcohol consumption (number/%)
r
P
r
Age, sex, BMI adjusted P
r
P
31 (18–65) 79/45Æ7
0Æ26
