Obesity, insulin resistance, and microvessel density.

The growing incidence and prevalence of the overweight/obese condition across developed economies worldwide has an enormous impact on increasing the risk for the development of impaired glycemic control or insulin resistance and ultimately peripheral vascular disease (PVD) in afflicted individuals. This places an enormous economic and social burden on these societies, in terms of additional health care costs and lost productivity and through a reduction in the quality of life of the individual owing, in part, to the progressive PVD. Characterized by an inability of the vascular systems to adequately perfuse tissues and organs relative to their metabolic demand, PVD is in part a function of a structural remodeling of the microvascular networks such that the density of microvessel and capillaries within tissues is reduced below that under normal conditions, with the potential for profound negative impacts on the processes of mass transport and exchange. The review discusses the severity of the obesity "epidemic" from the perspective of PVD and the effects of the development of the obese, insulin-resistant condition on tissue/organ microvessel density. Additional material is reviewed that addresses ameliorative treatments, primarily exercise training, on blunting microvessel loss in the obese, insulin-resistant individual, and on potential mechanistic contributors that warrant considerable future investigation.