Impaired angiogenesis and decreased
vascular endothelial growth factor (
VEGF) expression were recently documented in the remnant kidney (RK) model of progressive
renal failure.
VEGF (50 microg/kg, twice daily) was administered to RK rats between weeks 4 and 8 after surgery, and rats were euthanized at week 8 for histologic study. During the administration of
VEGF (n = 7) or vehicle (n = 6), systemic BP was comparable in the two groups.
VEGF treatment resulted in improved renal function and lower mortality rates, compared with the vehicle-treated group. Renal histologic analyses confirmed a 3.5-fold increase in glomerular endothelial cell proliferation (0.14 +/- 0.03 versus 0.04 +/- 0.02 proliferating endothelial cells/glomerulus,
VEGF versus vehicle, P < 0.05), a twofold increase in peritubular capillary endothelial cell proliferation (1.60 +/- 0.30 versus 0.78 +/- 0.17 cells/mm(2),
VEGF versus vehicle, P < 0.01), a threefold decrease in peritubular
capillary rarefaction (P < 0.01), and a twofold increase in endothelial
nitrix oxide synthase expression (P < 0.05) in the
VEGF-treated group; an eightfold increase in urinary
nitrate/
nitrite levels (P < 0.05) was also noted. Although the difference in glomerulosclerosis scores did not reach statistical significance (0.67 +/- 0.42 versus 1.22 +/- 0.63,
VEGF versus vehicle; range, 0 to 4; P = NS),
VEGF-treated rats exhibited less interstitial
collagen type III deposition (9.32 +/- 3.26 versus 17.45 +/- 7.50%,
VEGF versus vehicle, P < 0.01) and reduced tubular epithelial cell injury, as manifested by
osteopontin expression (5.57 +/- 1.60 versus 9.58 +/- 3.45%,
VEGF versus vehicle, P < 0.01). In conclusion,
VEGF treatment reduces
fibrosis and stabilizes renal function in the RK model. The use of angiogenic factors may represent a new approach to the treatment of
kidney disease.