Renin-angiotensin system components and endothelial proteins as markers of diabetic microvascular disease.

Endothelial cell damage, which is associated with local thrombin formation and inflammation, can lead to the release of endothelium-synthesized factors into plasma, such as vWFAg, TM, ACE and ET-1. These markers of endothelial damage are increased in some patients with diabetes mellitus, but the differences with normal are often small and not closely correlated with the severity of microvascular disease, as judged from the degree of albuminuria and the severity of retinopathy. Prorenin, which may also be related to abnormal endothelial cell function or endothelial damage, is elevated in many patients with diabetes, both type I and II, and its level is more closely correlated with the severity of microvascular disease. It is already elevated at an early stage. Further studies will reveal whether, in diabetes, an increased plasma prorenin is a reliable predictor of progressive microvascular disease. It is even conceivable that prorenin is not only a marker of diabetic microvascular disease but also has a role in its pathogenesis, via local proteolytic or non-proteolytic prorenin activation.