CELL-MEMBRANE FATTY-ACID COMPOSITION IN TYPE-1 (INSULIN-DEPENDENT) DIABETIC-PATIENTS - RELATIONSHIP WITH SODIUM-TRANSPORT ABNORMALITIES ANDMETABOLIC CONTROL

We have studied the fatty acid composition of erythrocyte membrane pho spholipids in nine Type 1 (insulin-dependent) diabetic patients and ni ne healthy control subjects. Cell membranes from the diabetic patients showed a marked decrease in the total amount of polyunsaturated fatty acids (19.0 % +/- 2.2 vs 24.6 % +/- 1.4, p < 0.0001) mainly at the ex pense of docosahexaenoic acid C22:6(n3) (2.9 % +/- 1.1 vs 5.3 % +/- 1. 3, p < 0.001), and arachidonic acid C20:4 n6 (12.0 % +/- 1.6 vs 15.1 % +/- 0.6, p < 0.0005). Conversely, the total amount of saturated fatty acids was significantly increased (p < 0.05) and the polyunsaturated/ saturated ratio was decreased in the Type 1 diabetic patients (p < 0.0 0005). Neither the time from diagnosis, nor C-peptide levels, correlat ed with parameters indicating a poor metabolic control of Type 1 diabe tes. However, C22:6(n-3) and total n-3 content significantly correlate d with HbA1c (r = -0.79 and r = -0.88, respectively, p < 0.01), fructo samine (r = -0.71 and r = -0.74, respectively, p < 0.05), and Na+-K+ A TPase activity (maximal rate/K(m) quotient) (r = 0.78 and r = 0.71, re spectively, p < 0.05). In conclusion we have found marked alterations of cell membrane lipid composition in Type 1 diabetic patients. These cell membrane abnormalities in lipid content were related to sodium tr ansport systems and to poor metabolic control. Either diet, or the dia betic state, might be responsible for the observed cell membrane abnor malities. A dietary intervention study might differentiate the role of diet and diabetes in the reported cell membrane alterations.