Erythrocyte Sodium-Hydrogen Antiport Activity is Not a Predictor of Diabetic Nephropathy

Abstract

Erythrocyte sodium-hydrogen antiport activity was measured by Odov's method in 36 healthy volunteers (18 with negative, 18 with positive family history of hypertension) and 52 subjects with type 1 insulin-dependent diabetes mellitus: 29 patients were without known diabetic complications, 23 patients with microangiopathy (10 with diabetic retinopathy, 13 with ‘incipient’ diabetic nephropathy). Normotensive healthy adults had similar antiport activities independently of a positive or negative family history of hypertension (6.45 ± 2.61 vs. 5.80 ± 3.07 mmol/l of cells per h, respectively). Sodium-hydrogen antiport resulted 8.38 ± 3.91 mmol/l of cells per h in the 29 uncomplicated diabetic patients, significantly higher (p < 0.05) compared to healthy subjects, both without and with family hypertension. Complicated diabetics confirmed to have an exchange rate higher than healthy controls (8.18 ± 2.50 mmol/l of cells per h, p < 0.01): patients with retinopathy showed the highest antipoit activity (8.96 ± 2.95 mmol/l of cells per h, p < 0.01), while patients with nephropathy had milder antiport overactivity (7.58 ± 2.02 mmol/l of cells per h), not significantly different from either uncomplicated diabetics or healthy controls. Thus, an increased sodium-hydrogen exchanage rate in peripheral erythrocytes does not seem to be an early indicator of diabetic nephropathy.

Key words

Erythrocyte Na-H Exchange - Family Hypertensive History - Type 1 Diabetes Mellitus