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

Abstract

Zinc-alpha2-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. This study aimed to address the relationship of serum ZAG levels with adiposity and cardiometabolic risk factors in humans. 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/m(2)] 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. 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 <or= 0.002). ZAG might be involved in the pathogenesis of obesity-related metabolic disorders in humans and thus warrants further investigation.