ENHANCED ERYTHROCYTE NA+ H+ EXCHANGE PREDICTS DIABETIC NEPHROPATHY INPATIENTS WITH IDDM/

Diabetic nephropathy develops in a subset of patients with an apparent ly hereditary predisposition, Microalbuminuria and elevated arterial p ressure have been proposed as predictors of nephropathy but both appea r when renal damage is impending, Enhanced sodium-hydrogen exchange in the cell membranes of diabetic patients is an early marker of diabeti c nephropathy but its predictive value has not been assessed. In this study, sodium-hydrogen exchange was measured in erythrocytes as an ini tial velocity of amiloride-inhibited H+ efflux (pH 6.35-6.45) into a N a+-containing medium (pH 7.95-8.05) in 156 non-microalbuminuric insuli n-treated diabetic patients (98 women, 58 men, age 33 +/- 8 years, dia betes duration prior to enrollment 15 +/- 4 years) during 8 years of f ollow-up. Enhanced erythrocyte sodium-hydrogen exchange predicted diab etic nephropathy alone and in association with a familial tendency to hypertension/nephropathy with 86 and 96 % sensitivity, and 80 % specif icity, Thus, sodium-hydrogen exchange appears to detect a subset of di abetic patients prone to develop renal damage, in whom a more intensiv e treatment modality might be considered.