Plasma factors and platelet aggregation in diabetes mellitus

Plasma fron some diabetic patients, particularly those with advanced retinopathy and nephropathy, will potentiate ADP-induced platelet aggregation. Partial purification of plasma from a diabetic patient with nephropathy has yielded a fraction with this activity. A linea dose response curve relating plasma factor (6.25-50 ng protein) and platelet aggregation or ATP release at 4 minutes after adding ADP has been found. The effect is blocked by exposure of platelets to aspirin, prostaglandin or eicosapentaenoic acid. Soluble immune complexes are found in many diabetics and are known to be platelet-active. We have isolated immune complexes from sera of six diabetics and have shown enhancement of the second phase of platelet aggregation and of ATP release by these immune complexes from platelets sensitized to ADP. We conclude that plasma proteins from diabetics may accentuate ADP-induced platelet aggregation and ATP release, possibly by acting through prostaglandin pathways. Immune complexes appear to be one group of plasma proteins with such platelet active behavior. Further studies are indicated to characterize these plasma factors and to assess their in vivo significance regarding platelet function and vascular disease in diabetes mellitus.