Advanced glycation end-product levels in subtotally nephrectomized rats: Beneficial effects of angiotensin II receptor 1 antagonist losartan

The angiotensin II receptor 1 antagonist losartan (L) inhibited the advanced glycated end-products (AGEs) induced expression of transforming growth factor β₁ in in vitro experiments performed on renal tubuloepithelial cells. To test the pathophysiological importance of these findings, the possible link between serum AGEs levels and angiotensin system was investigated in the model of normotensive subtotally nephrectomized rats (4/6-NX). Concentration of AGEs in serum of placebo administered 4/6-NX rats (n=7, 1.09±0.09 U/l) increased slightly in comparison with sham-operated healthy controls (CTRL, n=8, 0.94±0.10 U/l, p <0.02) as measured by competitive ELISA. Treatment of 4/6-NX rats with L over 12 weeks ameliorated the rise in serum AGEs concentration (1.00±0.12 U/l, n= 15 p<0.005) almost to the level observed for CTRL. This effect was further corroborated by the observation, that the impaired renal excretion of AGEs in 4/6-NX-placebo rats (0.07±0.02 U/μmol creatinine) was significantly restored by L (0.09±0.02 U/μmol creatinine, p <0.009) and resembled that of the CTRL (0.10±0.03 U/μmol creatinine). Administration of L to 4/6-NX rats significantly improved renal function as evaluated by a smaller rise in serum creatinine and urea concentration. In spite of the improvement in renal function, there were no differences in concentrations of transforming growth factor β₁ in serum and in urine among the two groups. These effects were independent of blood pressure. Our data give first evidence, that long-term treatment with angiotensin II receptor 1 antagonist may exert salutary effects on AGEs levels in the rat remnant kidney model, probably due to improved renal function. Copyright (C) 2000 S. Karger AG, Basel.