Platelet activation, endothelial dysfunction and inflammation may be involved in early stages of diabetic microangiopathy. We therefore investigated patients with Type 1 diabetes mellitus, without (n=19) and with (n=20) microangiopathy, matched for glycaemic control and duration of disease, and matched with healthy control subjects (n=27).

Platelet activation was measured as platelet P-selectin expression using whole blood flow cytometry and as soluble P-selectin by immunoassay. Von Willebrand factor antigen in plasma, serum soluble E-selectin, CD40 ligand (sCD40L) and C-reactive protein (CRP) served as markers for endothelial function and inflammation.

Thrombin-induced platelet P-selectin expression was enhanced, and soluble P-selectin and sCD40L concentrations were increased in patients with microangiopathy compared with the control subjects (p<0.01 for both) and with patients without microangiopathy (p<0.05 for P-selectin expression and sP-selectin), whereas all three parameters were similar in patients without microangiopathy and in the control subjects. CRP and soluble E-selectin were increased in patients with microangiopathy, compared with the control subjects (p<0.01 and p<0.05), whereas von Willebrand factor did not differ between the groups.

Microangiopathy in Type 1 diabetes is associated with platelet hyperactivity, endothelial dysfunction and low-grade inflammation, indicating an increased risk for cardiovascular disease.