Serum levels of the adipokine vaspin in relation to metabolic and renal parameters

Context: Recently, vaspin was identified as an insulin-sensitizing adipokine. However, regulation of this adipocyte-secreted factor in human disease has not been determined. Objective: We investigated vaspin serum concentrations in diabetic and nondiabetic patients on chronic hemodialysis (CD) as compared with controls with a glomerular filtration rate (GFR) above 50 ml/min. Design: Vaspin was quantified by ELISA in control (n = 60) and CD (n = 60) patients and correlated to clinical and biochemical measures of renal function, glucose, and lipid metabolism, as well as inflammation, in both groups. Results: Mean serum vaspin concentrations were not significantly different between CD patients and controls. Circulating vaspin was significantly lower in males (0.6 +/- 0.9 mu g/liter) as compared with females (1.3 +/- 1.5 mu g/liter) and was decreased in insulin-treated subjects. In univariate analyses, vaspin levels positively correlated with age and high-density lipoprotein cholesterol and negatively with waist-to-hip ratio and GFR in control patients, whereas the adipokine was negatively associated with GFR and C-reactive protein (CRP) in CD patients. In multivariate analyses, age and gender were independently associated with vaspin in controls, whereas gender, GFR, and CRP independently predicted circulating vaspin in CD patients. Conclusions: Vaspin levels are significantly higher in women, and gender is an independent predictor of circulating vaspin in both control and CD patients. In addition, age independently predicts vaspin in control patients, whereas GFR and CRP are independently associated with this adipokine in CD patients. In contrast, circulating vaspin is not independently associated with markers of glucose and lipid metabolism.