Visceral Adiposity Index (VAI) as a simple indicator of “adipose tissue dysfunction” in patients with type 2 diabetes.

Abstract

Although still there is no a clear definition of “adipose tissue dysfunction”, the identification of clinical and biological markers of altered fat distribution and function may provide the needed tools to early identify a condition of cardiometabolic risk. Visceral Adiposity Index (VAI) is a mathematical gender-specific index estimated with the use of simple anthropometric [(BMI and Waist circumference (WC)] and biochemical parameters [HDL cholesterol (HDL) and Triglycerides (Tg)], that in recent studies has shown to reflect accurately the degree of visceral adiposity and insulin resistance. However, although VAI has been indirectly shown to be a marker of impaired fat distribution and function, until to date there are only few studies in which it was correlated with the main adipokines (leptin and adiponectin). Our aim was to evaluate the correlations among various measures of fat distribution [VAI, BMI, WC, WHR, visceral adipose tissue volume (VAT ) and subcutaneous adipose tissue volume (SAT) measured by MR between L2 and L4] and a complete panel of adipocytokines [Visfatin, Resistin, Leptin, Soluble leptin receptors (sOB-R), Leptin/sOb-R ratio, Adiponectin, Ghrelin, Adipsin, PAI-1, vascular endothelial growth factor (VEGF), TNF-alpha,??hs-CRP, IL-6, IL-18, Hepatocyte growth factor (HGF)]?in patients with type 2 diabetes (DM2). Ninety-one DM2 patients (age: 65.25±6.38 years; duration of disease: 9.73±5.99 years; 42 men and 49 women) in stable treatment for the last two months with metformin in monotherapy at 2 g/day were screened for the study. In all patients the serum levels of adipocytokines were assayed by Luminexbased kits. In a subset of 13 patients an assessment of VAT and SAT volume was performed through a MR. At the Pearson's correlation, among all the investigated measures of fat distribution, only VAI showed a significant correlation with almost all analyzed cytokines [visfatin (r=0.331, p=0.001), resistin (r=0.354, p=0.001), leptin (r=0.285, p=0.005), sOb-R (r=-0.214, p=0.041), ghrelin (r=-0.225, p=0.032), adiponectin (r=-0.394, p<0.001), VEGF (r=0.247, p=0.018), TNF-alpha (??r=0.333, ??p=0.001), HGF (r=0.245, p=0.019), IL-18 (r=0.317, p=0.002)]; no significant correlation with PAI-1 and adipsin was found. Our study suggests VAI, among the most common indexes of adiposity assessment, is a very useful tool well mirroring “adipose tissue dysfunction” in type 2 diabetes.