Platelet abnormalities in diabetes mellitus.

Patients with diabetes mellitus have an increased risk of thrombosis and accelerated atherogenesis. Increased platelet adhesion and aggregation are noted in vitro. This paper reviews known platelet abnormalities found in patients with diabetes mellitus (DM) and examines the pathophysiology associated with these abnormalities. Four general platelet regions or functional units can be involved in aberrant chemistry, structure and/or function. These include (1) the membrane, (2) granules, (3) intermediary metabolism, and (4) other factors and/or platelet responses to various substances. In regard to the abnormalities of the membrane, there is an increased binding of fibrinogen in diabetic rats and increased membrane rigidity. There are increases in glycoprotein Ib and glycoprotein IIb/IIIa. Related to granule function, increased levels of plasma serotonin, histamine and beta thromboglobulin are found. Alterations of intermediary metabolism involving the prostaglandin pathways, arachidonic acid, Vitamin E, and lipids have been reported. Other factors which are not well characterized include abnormalities of stem cell response to growth factors and thrombopoiesis, as noted indirectly through alterations of platelet volumes. It is proposed that these platelet abnormalities result in increased thrombosis and/or an acceleration of the atherosclerotic process in at least some patients with diabetes mellitus.