Urinary excretion of glutathione S transferases alpha and pi in patients with proteinuria: Reflection of the site of tubular injury

Citation
Ajw. Branten et al., Urinary excretion of glutathione S transferases alpha and pi in patients with proteinuria: Reflection of the site of tubular injury, NEPHRON, 85(2), 2000, pp. 120-126
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Urology & Nephrology","da verificare
Journal title
NEPHRON
ISSN journal
0028-2766 → ACNP
Volume
85
Issue
2
Year of publication
2000
Pages
120 - 126
Database
ISI
SICI code
0028-2766(200006)85:2<120:UEOGST>2.0.ZU;2-I
Abstract
In patients with renal diseases, proteinuria is a major determinant of prog ressive renal failure, probably by causing tubular cell injury. Little is k nown on extent and site of tubular cell injury in patients with proteinuria . Glutathione S transferases (GST) are cytosolic enzymes. The alpha isoform is present only in proximal tubular cells, whereas the pi isoform is confi ned to distal tubular cells. We have studied the urinary excretion of both isoenzymes in 56 (38 male and 18 female) patients with glomerular diseases and proteinuria. The mean age was 45 +/- (SD) 16 years, the median creatini ne clearance was 80 (range 27-159) ml/min, and the median albuminuria was 4 .2 (range 0.7-16.9) g/10 mmol creatinine. The excretions of both GST alpha (median 35.9 ng/10 mmol creatinine) and GST pi (median 24.8 ng/10 mmol crea tinine) were elevated as compared with control values (upper limits 10 and 12 ng/10 mmol creatinine, respectively). The urinary excretion of GST pi, b ut not that of GST alpha, was inversely correlated with the creatinine clea rance. The highest levels of GST alpha were found in patients with a well-p reserved renal function, whereas highest levels of GST pi were found in pat ients with renal failure. In a small number of patients we performed immuno fluorescent studies of renal tissue. An increased urinary excretion of GST alpha correlated with brush border damage and decreased staining of proxima l tubules for that isoenzyme. Our data suggest that in patients with protei nuria initial injury is apparent at the proximal tubules. Measurements of G ST alpha and GST pi appear useful to study longitudinal timing and site of proteinuria-induced tubular cell injury. Copyright (C) 2000 S. Karger AG, B asel.