Analysis of Relative Expression Level of VEGF (Vascular Endothelial Growth Factor), HIF-1α (Hypoxia Inducible Factor 1α) and CTGF (Connective Tissue Growth Factor) Genes in Chronic Glomerulonephritis (CGN) Patients

Abstract

Background/Aims: Analysis of gene expression in renal tissue is considered to be a diagnostic tool predicting the clinical course of glomerulonephritis. The present study quantified the relative transcript levels of VEGF, CTGF and HIF-1α in renal tissue to establish their relationship with some clinical variables in patients suffering from chronic glomerulonephritis (CGN). Methods: 28 patients (6F and 22M, mean age 51.2±15.0) with CGN were enrolled. Type of CNG recognized by kidney biopsy (histopatological evaluation) was as follows: minimal change disease (MCD)-3pts, IgA nephropathy-5pts, FSGS-3pts, membranous nephropathy-4pts, mesangio-proliferative glomerulonephritis-3pts; MPGN-1pts, lupus nephritis-6pts, granulomatosis with polyangitis-2 pts; hypertensive nephropathy- 3pts. Renal tissue from 3 individuals with normal eGFR and histology was taken as control. Mean clinical follow-up of patients was 12 months after biopsy eGFR and daily urinary protein excretion (DPE) was assessed at the time of biopsy and then in 6 months intervals. Real-time PCR was used to determine relative gene expression. The housekeeping gene GAPDH was used as normalization control. Results: At the time of the biopsy relative expression of 3 analyzed genes was diminished in comparison to control. There were statistically significant differences in VEGF gene relative expression level in patients which varied according to eGFR and tendency in patients which varied according to DPE. HIF-alfa and CTGF gene showed only a tendency. Conclusions: Overexpression of the VEGF gene in subjects with DPE>3,5g may point to insufficient oxygen supply in renal tissue which may result in tubulointerstitial fibrosis with further functional renal impairment and decline of eGFR.