Platelet factor 4 (PF4) and heparin released platelet factor 4 (HR-PF4) in diabetes mellitus. Effect of the duration of the disease.

: Several investigators have reported an altered platelet function in diabetes mellitus as measured by elevated levels of platelet specific proteins platelet factor 4 (PF4) and B-thromboglobulin (BTG). We studied 20 insulin dependent (IDD), 20 non insulin dependent (NIDD) diabetic males without overt clinical symptoms of cardiovascular disorders and 30 normal controls. We evaluated PF4, BTG and heparin released platelet factor 4 (HR-PF4) as measured 2.5 minutes after a bolus injection of 5,000 I.U. of a commercial mucous heparin. The patients showed normal levels of both PF4 and BTG. Furthermore HR-PF4 failed to show statistically significant variation between patients and controls. However when the diabetics were divided on the basis of the duration of the disease, the IDD had an increased HR-PF4 mean level and the trend became statistically significant when diabetes existed more than 17 years (patients HR-PF4 149.1 ng/ml, range 17.3-194; controls HR-PF4 110.9 ng/ml range 50-160, less than p less than 0.05). NIDD failed to reveal the same pattern. Although the significance of HR-PF4 is unknown, insulin dependent diabetes mellitus after many years could cause a potentially dangerous, silent vascular damage with enhanced platelet vessel wall interaction as measured by an elevated HR-PF4.