Serum Zinc-α2-Glycoprotein Correlates with Adiposity, Triglycerides, and the Key Components of the Metabolic Syndrome in Chinese Subjects

Abstract

Context: Zinc-α2-glycoprotein (ZAG) is a 40-kDa circulating glycoprotein secreted from the liver and adipose tissues. Animal studies have demonstrated the role of ZAG as a lipid-mobilizing factor involved in regulating lipid metabolism and adiposity. However, the clinical relevance of these findings remains to be established.Objective: This study aimed to address the relationship of serum ZAG levels with adiposity and cardiometabolic risk factors in humans.Design and Setting: A total of 258 Chinese subjects [aged 55.1 ± 12.5 yr; 120 males, 138 females; body mass index (BMI), 25.4 ± 4.1 kg/m2] were randomly selected from the population-based Hong Kong Cardiovascular Risk Factor Prevalence Study, based on their BMI. Serum ZAG levels were determined with ELISA. The relationship between serum ZAG levels and cardiometabolic parameters was assessed.Results: Serum ZAG levels were higher in men (P < 0.001 vs. women). Serum ZAG correlated positively with age, parameters of adiposity (waist circumference and BMI), fasting insulin, insulin resistance indices, serum triglycerides, adipocyte-fatty acid-binding protein, and C-reactive protein, and diastolic blood pressure (all P < 0.005, age- and sex-adjusted), and inversely with high-density lipoprotein-cholesterol levels (P = 0.008, age- and sex-adjusted). It was also elevated progressively with an increasing number of components of the metabolic syndrome (P for trend < 0.001). On multivariate analysis, serum ZAG was independently associated with male sex, the metabolic syndrome (or type 2 diabetes and serum triglycerides), and C-reactive protein (all P ≤ 0.002).Conclusions: ZAG might be involved in the pathogenesis of obesity-related metabolic disorders in humans and thus warrants further investigation.