Expression of tissue fibrosis genes in congenitally obstructed pyeloureteral junction and biomarkers of renal damage.

Introduction: The aim of this study was to investigate the expression of fibrosis-related genes in obstructed ureteral tissue and determine its relationship with biomarkers of renal damage and preoperative renal scan findings.

Material and methods: In all cases, bladder urine and blood samples were collected preoperatively. They were analysed for serum cystatin C, urinary albumin, urinary beta 2 microglobulin, and urinary neutrophil gelatinase-associated lipocalin concentrations, as well as their concentrations standardised by urine creatinine. Pyeloureteral junction obstruction tissue specimens were frozen in liquid nitrogen upon harvesting. RNA was extracted from the samples using TRIzol reagent. qPCR was performed, and the relative expressions of TGFβ1, MMP1, TIMP1, PAI1, CTGF, and VEGFA in stenotic ureteral tissue were calculated. Spearman's rank correlation test was used to calculate the correlation between the relative expression of investigated genes, urine, and blood biomarkers of renal damage and preoperative renal scan findings.

Results: A total of 20 pyeloureteral junctions of 20 patients were harvested at the time of dismembered pyeloplasty. The median age of the patients at the time of the operation was 15.2 [9.07, 66.2] months. There was a significant negative correlation between urinary albumin concentration and relative TGFβ1 expression in pyeloureteral junction tissue (rho = -0.45, p = 0.047), as well as between uAlb and relative VEGFA expression (rho = -0.575, p = 0.008). No correlation with other urine biomarkers of renal damage or renal scan findings was found.

Conclusions: Expression of fibrosis-related genes in the obstructive tissue of the pyeloureteral junction have no direct correlation with biomarkers of renal damage.