ABSTRACT
Microvascular complications of diabetes mellitus represent the most serious complications that burden normal life in insulin dependent diabetic patients. It has been speculated that platelet activation and von Willebrand factor [vWF] activity might contribute to the evolution of microvascular complications in patients with insulin dependent diabetes mellitus [IDDM]. In this study, platelet aggregation [in response to ADP and ristocetin] and vWF activity were measured in 20 children with IDDM who were clinically free from demonstrable microvascular complications, and in 10 normal healthy children of matched age and sex served as control group. The results showed an abnormal platelet behavior in diabetic children that was characterized by irreversible aggregation with low dose of ADP and significant increase in peak wave length of platelet aggregation with both ADP and ristocetin. Also the activity of vWF which is a marker of endothelial cell function was significantly higher in diabetic children compared to control group. The studied parameters, were compared with the state of metabolic control, namely glycemic control by measurement of glycated haemoglobin [Hb A1c] and the lipidemic state assessed by serum total cholesterol levels. Platelet aggregation was positively correlated with the serum cholesterol level while vWF was positively correlated with the level of glycated haemoglobin. Meanwhile vWF activity was positively correlated with platelet aggregation. To conclude; the results of this study suggest that diabetic children who are clinically free from detectable microvascular complications might be at the onset of preclinical microangiopathy manifesting itself by the enhanced platelet aggregation and endothelial cell dysfunction [high vWF activity]. Both the glycemic and lipidemic states seem to affect the enhanced platelet activation and increased vWF