Evidence for a relationship between VEGF and BMI independent of insulin sensitivity by glucose clamp procedure in a homogenous group healthy young men

This is the first study to experimentally explore the direct relationship between circulating VEGF levels and body mass index (BMI) as well as to unravel the role of insulin sensitivity in this context under standardized glucose clamp conditions as the methodical gold-standard. In order to control for known influencing factors such as gender, medication, and arterial hypertension, we examined a highly homogeneous group of young male subjects. Moreover, to encompass also subjects beyond the normal BMI range, low weight and obese participants were additionally included and stress hormones as a main regulator of VEGF were assessed. Under euglycemic clamp conditions, VEGF was measured in 15 normal weight (BMI 20-25 kg/m(2)), 15 low weight (BMI30 kg/m(2)) male subjects aged 18-30 years and the insulin sensitivity index (ISI) was calculated. Since stress axis activation promotes VEGF secretion, concentrations of ACTH, cortisol, and catecholamines were monitored. Despite of comparable ACTH (P = 0.145), cortisol (P = 0.840), and norepinephrine (P = 0.065) levels, VEGF concentrations differed significantly between BMI-groups (P = 0.008) with higher concentrations in obese subjects as compared to normal weight (P = 0.061) and low weight subjects (P = 0.002). Pearson's correlation analysis revealed a positive relationship between BMI and VEGF levels (r = 0.407; P = 0.010) but no correlation of VEGF with ISI (r = 0.224; P = 0.175). Our data demonstrate a positive correlation between concentrations of circulating VEGF levels and BMI in healthy male subjects under highly controlled conditions. This relationship which is apparently disconnected from insulin sensitivity may be part of some pathogenetic mechanisms underlying obesity and type 2 diabetes.