Not all vascular complications of diabetes are specific to this disease. Atherosclerosis of the coronary arteries in diabetic patients does not differ from that in the nondiabetic; it is merely more frequent. Specific, however, are the changes in the microvasculature. It is therefore not surprising that much attention has centered on these changes in diabetic retinopathy.
Some of this attention is being currently diverted from vessel wall to vessel content, particularly to the fibrinolytic and clotting systems. It is becoming increasingly apparent that fibrinolytic activity and platelet aggregation may play an important pathogenetic role in the capillary closure,1 which is one of the earliest manifestations of diabetic retinopathy.
The fibrinolytic system is a defensive mechanism against vascular occlusion by platelet plugs and subsequent clots. Paul and Adlakha2 found this activity to be decreased in two patients with diabetic retinopathy. Fukuda3 reported similar observations in diabetic patients with