Microangiopathy in diabetes mellitus: II. Features, complications and investigation.

This paper reviews the current literature on the morphological, physiological, pathological and rheological features of microangiopathy in diabetes mellitus. The current theories explaining the development of these features as well as complications resulting from them are discussed. In the first section the morphological changes including capillary basement membrane thickening as well as physiological changes such as increased permeability and reduced diffusion of oxygen across capillary endothelium are discussed. Rheological factors and functional changes in blood flow as well as capillary proliferation and degeneration are addressed. The second section of this paper deals with the complications suffered by diabetics such as retinopathy, nephropathy, neuropathy, cardiovascular disease and skin ulceration. The role of microangiopathy in the pathogenesis of these complications is reviewed. The last section discusses the investigative techniques available to the clinician and researcher in the study of micro-angiopathy. These include various methods of blood flow measurement such as plethysmography, LASER Doppler flowmetry, capillary microscopy and clearance of tracers from the skin microcirculation.