ARB treatment prevents the decrease in endothelial progenitor cells and the loss of renal microvasculature in remnant...

Endothelial progenitor cells (EPCs) are involved in endothelium turnover and play a role in renal capillary repair. Since angiotensin II has been shown to negatively affect EPCs and blockade of angiotensin II decreases the progression of renal diseases, we investigated the effects of losartan on EPCs and renal endothelial cells in remnant kidney.

Sprague-Dawley rats were randomized to receive losartan (25 mg/kg/day) or solvent for 15 weeks after 5/6 nephrectomy. Peripheral blood CD34+ EPCs were counted and the number of CD31+ endothelial colonies was determined. Glomerular and tubulointerstitial capillary endothelial cells were assessed and vascular endothelial growth factor (VEGF) and thrombospondin (TSP-1) expression were determined.

EPCs and the number of endothelial colonies were significantly reduced in 5/6 nephrectomized rats, which was associated with a decrease in glomerular and tubulointerstitial endothelial cells, a decrease in VEGF and an increase in TSP-1 expression. Losartan treatment largely prevented changes in both EPCs and remnant kidney.

The gradual loss of renal capillaries in remnant kidney was associated with decreased EPCs and endothelial colonies, hindering capillary endothelial repair in remnant kidney. Losartan treatment largely prevented the loss of EPCs and preserved renal endothelial cells, which may be part of the mechanism of how it contributes to renal protection.