Diabetic microangiopathy: pathology and current understanding of its pathogenesis.

Recent drastic increase in diabetic population poses serious problems in both health sciences and socioeconomic conditions. The most important issue in the clinical practice of diabetic patients is the treatment and care of chronic complications. It is not fully clear, however, as to the pathophysiology of diabetic microangiopathy and its pathogenesis. Recent studies on microvessel pathology in diabetic patients and molecular analyses on the diabetic animal models disclosed novel features of the dynamic changes of specific organ pathology affected by diabetes and factors involved in its pathogenesis. Under long-term hyperglycemia, early stimuli elicit adaptive reactions of tissues showing acute inflammatory processes of vessel walls and then late irreversible and regressive changes of microangiopathy. Consequently, remodeling of vascular cells and excessive matrix production are cardinal feature. The precise mechanisms of how these tissue changes occur remain speculative; increased polyol pathway, excessive non-enzymatic glycation, increased protein kinase C activity, as well as oxidative stress are all interrelated for the cause and development of the microangiopathy.