Serum Levels of VEGF in IgA Nephropathy

Lee, Soo Bong; Lee, Dong Won; Kim, Yong Bum; Jung, Hyun Chul; Kwak, Ihm Soo; Rha, Ha Yeon

Abstract

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent enhancer of microvascular permeability and a selective endothelial cell growth factor. In human kidney, VEGF is expressed mainly in glomerular visceral epithelial cells. We investigated the relationship between serum levels of VEGF and factors reflecting the severity of disease including histological patterns in order to elucidate the relevance of VEGF in the pathogenesis of IgA nephropathy.
METHODS
Serum VEGF was studied using a sandwich ELISA from 21 patients with IgA nephropathy. Histological patterns are classified to 5 grades by WHO classification and frequencies of crescent and glomerular sclerosis, degree of interstitial fibrosis were recorded. Serum concentrations of creatinine, albumin, IgA, amounts of 24 hour urine protein excretion, and creatinine clearances are also evaluated.
RESULTS
Serum VEGF levels were significantly correlated with histological grade(r=0.471, p < 0.05), frequency of cellular crescent(r=0.485, p < 0.05), degree of interstitial fibrosis(r=0.562, p < 0.01), and 24 hour urine protein excretion(r=0.439, p < 0.05), and inversely with serum albumin concentration(r=-0.594, p < 0.01). Studies in 17 patients without crescent formation revealed that only serum albumin concentration showed significant correlation with serum VEGF level.
CONCLUSION
Serum VEGF concentration is mainly correlated with cellular crescent formation reflecting activity of the disease rather than chronic structural changes such as glomerular sclerosis or interstitial fibrosis. Elevated serum VEGF concentration seems to be due to the release of relatively large amounts of stored VEGF from damaged visceral epithelial cells. Serum VEGF concentration may be a useful marker to evaluate the degree of acute renal injury, especially cellular crescent formation.