RESUMO
Background: The pathogenesis of renal scarring following acute pyelonephritis [APN] remains unclear
Objectives: We sought to investigate the implication of the common polymorphisms in the renin-angiotensin system [RAS] genes, and other risk factors, in the development of renal scarring following APN in Egyptian children
Methods: 414 patients with culture-confirmed urinary tract infection were examined by DMSA-scans for diagnosis of APN and voiding cystourethrogram to test for vesicoureteric reflux [VUR]. Genetic polymorphisms at three RAS genes [ACE I/D, ATR-1 A1166C and AGT M235T] were analyzed by PCR and DNA sequencing in APN patients and 140 control children. Follow up DMSA-scans were performed 6-9 months later to detect renal scarring
Results: APN was diagnosed in 63 patients [34 boys and 29 girls] aging 2 months-12 years. Renal scarring was detected in 40 patients. VUR was the only independent risk factor for renal scarring [P=0.01]. The D-allele of ACE gene was significantly more frequent in the scarring group [76.25%] compared to non-scarring group [57.8%] and controls [56.7%]; P=0.035 and 0.003, respectively. However, the frequencies of ATR-1 and AGT genotypes and alleles in scarring and non-scarring groups did not show significant difference. The ACE I/D polymorphism was significantly and tightly associated with renal scarring [OR=2.6, CI=1.04-4.94, P=0.039]. In contrast, AGT and ATR-1 polymorphisms could not be associated with renal scarring after APN [P=0.108 and P=0.821, respectively]
Conclusion: VUR is an independent risk factor for renal scarring following APN. The ACE D allele may be one of the genetic susceptibility factors contributing to adverse renal prognosis in Egyptian children