ALTERATIONS IN ERYTHROCYTE AGGREGABILITY IN DIABETICS - THE INFLUENCEOF PLASMATIC FIBRINOGEN AND PHOSPHOLIPIDS OF THE RED-BLOOD-CELL MEMBRANE

In order to ascertain whether the increased aggregability observed in the red blood cells of diabetic patients is induced exclusively by pla sma factors or is also influenced by membrane lipids, we examined the phospholipids of the erythrocyte membrane, the plasma fibrinogen conce ntration and erythrocyte aggregation in 86 insulin and non insulin-dep endent diabetic patients. The data obtained show that the erythrocyte aggregability of the diabetic patients is higher than that of the cont rol group (10.0 +/- 2.4 vs. 7.8 +/- 1.6%). This increased aggregabilit y correlates not only with a higher fibrinogen concentration but also with changes observed in the membrane phospholipids. The percentage of sphingomyelin (SP) in the patients is higher than in the controls (22 .6 +/- 6.8 vs. 18.4 +/- 5.4%) and that of phosphatidylserine (PS) is l ower (9.5 +/- 6.1 vs. 12.1 +/- 5.1%). No differences in the percentage s of the other two phospholipids identified (phosphatidylcholine, PC, and phosphatidylethanolamine, PE) were observed. The increase in the s aturated nature of the phospholipids of the erythrocyte membrane, whic h can be measured by the (SP + PC)/(PE + PS) ratio, is statistically r elated (r = 0.39; p < 0.05) to the increased red blood cell aggregabil ity observed in these patients.