Platelet Regeneration Time In Diabetics With And Without Retinopathy

Platelet regeneration time was measured by a modification of the Stuart technique which depends on progressive reappearance of the capacity to synthesize malondial- dehyde (MDA) in response to thrombin stimulation following aspirin ingestion. The subjects of the study were 40 normal subjects and 40 patients with insulin-dependent diabetes mellitus for more than 10 years. The presence or absence of retinopathy was independently assessed in a diabetic eye clinic and severe retinopathy was found in 20 patients. The mean platelet regeneration time in normal subjects was 9.98 ±0.22 days (mean ± SEM). In diabetic patients without retinopathy the platelet regeneration time was significantly (p<0.001) shortened (7.38 ± 0.14 days) and a further shortening occurred in those patients with retinopathy (6.80 ± 0.18 days), but with the number of subjects studied the difference between these two groups was not statistically significant. MDA produced in response to thrombin-stimulation of platelets was 235.5 ± 12.8 pmole/10⁸ platelets in controls with significantly (p<0.001) less in diabetics with retinopathy at 156.7 ± 17.5 pmole/10⁸ platelets. In 10 diabetic patients a standard oral glucose tolerance test was performed with blood taken for MDA at the same time as plasma glucose levels. There was no correlation between plasma glucose and the concentration of MDA produced. These results show that patients with longstanding insulin-dependent diabetes have an accelerated platelet regeneration time even in the absence of overt retinal microvascular complications.