Insulin-Induced Microvascular Recruitment in Skin and Muscle are Related and Both are Associated with Whole-Body Glucose Uptake

Objective: Insulin-induced capillary recruitment is considered a determinant of insulin-mediated glucose uptake. Insulin action on the microvasculature has been assessed in skin; however, there is concern as to whether the vascular responses observed in skin reflect those in the muscle. We hypothesized that insulin-induced capillary recruitment in skin would correlate with microvascular recruitment in muscle in a group of subjects displaying a wide variation in insulin sensitivity. Methods: Capillary recruitment in skin was assessed using capillary videomicroscopy, and skeletal muscle microvascular recruitment (i.e., increase in MBV) was studied using CEU in healthy volunteers (n=18, mean age: 30.6±11.1years). Both microvascular measurements were performed during saline infusion, and during a hyperinsulinemic euglycemic clamp. Results: During hyperinsulinemia, capillary recruitment in skin was augmented from 58.1±18.2% to 81.0±23.9% (p<0.0001). Hyperinsulinemia increased MBV in muscle from 7.00 (2.66-17.67) to 10.06 (2.70-41.81) units (p=0.003). Insulin's vascular effect in skin and muscle was correlated (r=0.57). Insulin's microvascular effects in skin and muscle showed comparable strong correlations with insulin-mediated glucose uptake (r=0.73 and 0.68, respectively). Conclusions: Insulin-augmented capillary recruitment in skin parallels insulin-mediated microvascular recruitment in muscle and both are related to insulin-mediated glucose uptake. © 2012 John Wiley & Sons Ltd.