Expression of Platelet-Derived Endothelial Cell Growth Factor and its Potential Role in Up-Regulation of Angiogenesis in Scarred Kidneys Secondary to Urinary Tract Diseases

The mechanism of neovascularization secondary to renal interstitial fibrosis is not well understood. Platelet-derived endothelial cell growth factor (PD-ECGF) is known to promote angiogenesis. We examined the expression of PD-ECGF immunohistochemically in 9 normal kidneys and 26 scarred kidneys secondary to urinary tract diseases. To estimate up-regulation of angiogenesis, microvessels were counted by immunostaining endothelial cells for CD34. Immunostaining of PD-ECGF was observed in most Bowman's capsules, occasional tubules, and some interstitial mononuclear cells in normal kidneys. A remarkable increase of immunostained PD-ECGF was found in the tubules and interstitial mononuclear infiltrates in the scarred kidneys. The predominant cell type in the infiltrate was T cells (CD3 + ). The microvessel count and mean numbers of PD-ECGF + tubular and interstitial mononuclear cells increased with increasing interstitial fibrosis. A significant correlation was noted between microvessel count and the number of PD-ECGF + tubular cells ( P = 0.0002) or PD-ECGF + interstitial mononuclear cells ( P