[Pathogenesis and therapy of type I and type II diabetes mellitus]

Diabetes mellitus is a heterogenous syndrome. Insulin dependent type I diabetes is characterised by progressive beta-cell-loss, resulting in a deterioration of insulin secretion. Cause of the beta-cell-destruction is a chronic autoimmune process, which starts already months to years before manifestation of the disease. New advances in the diagnosis of the autoimmune mechanisms, which are responsible for type I diabetes might help to prevent type I diabetes by immunization or immunosuppressive therapy in the near future. At the moment multiple daily insulin injections are the substitution therapy of the choice in type I diabetes mellitus. This kind of therapy is designed to imitate the physiologic dynamics of insulin secretion in healthy subjects. In non insulin dependent diabetes a defect in insulin action seems to be the primary cause of the disease although there are also defects in insulin secretion in type II diabetes mellitus. Most type II diabetics are overweight at the beginning of the disease and the primary goal of therapy in these patients is normalization of bodyweight and improvement of peripheral and hepatic insulin sensitivity. Regular exercise is seen as a cornerstone in the treatment of type I and type II diabetes. Besides the acute blood glucose lowering effect of exercise, regular exercise has beneficial effects on the circulatory system and muscle system, leads to an increase in insulin sensitivity, to a decrease of the daily insulin dosage and to a stabilization of metabolic control. Furthermore beneficial effects of exercise on plasma lipids and lipoproteins are reported. In overweight diabetics regular exercise facilitates normalization of body weight.