[Endothelium and its morphofunctional changes in the pathogenesis of diabetic microangiopathy]

Recent advances in our knowledge of endothelial function in health and in the presence of generalized microvascular damage, such as found in diabetic microangiopathy, are discussed in this review article. In microangiopathy there are no typical morphological signs of endothelial stress, apart from ubiquitous thickening of the basement membrane and the finding of both hyper- and acellular capillaries, whereas important derangements of endothelial function may occur in the early stages of the disease, like accelerated turnover, intracellular accumulation of potentially toxic intermediate metabolites, hyperpermeability of the vessel wall, altered synthesis of some haemostatic factors, expression of angiogenetic potentialities in inappropriate situations. The possible pathogenetic mechanisms underlying such alterations are reviewed, with special emphasis on the shortcomings of the experimental models available for laboratory investigation and on the in vivo situation.