Tubular urinary enzymes in acute post-infectious glomerulonephritis.
Tubular function of 17 pediatric patients with a mild form of acute post-infectious glomerulonephritis was prospectively evaluated by assessment of the urinary activity of proximal and distal tubule enzymes. Neutral-like endopeptidase (NEP-like) and angiotensin-converting enzyme (ACE) were the proximal tubule enzymes assessed, while prolyl-endopeptidase (PE) and serine-endopeptidase H1 and H2 were the distal tubule enzymes analyzed. Urine was collected at diagnosis (T0) and after 2 (T2) and 6 (T6) months of follow-up. NEP-like enzyme activity (nmol/mg creatinine; median+/-quartile range) was increased at diagnosis, and this remained stable during the first 6 months (T0 18.30+/-83.26, T2 17.32+/-49.56, T6 23.38+/-107.18). Urinary activity of the other enzymes was as follows: ACE (mU/ml per mg creatinine) T0 0.08+/-0.16, T2 0.06+/-0.10, T6 0.18+/-0.29; PE (nmol/mg creatinine) T0 6.70+/-84.87, T2 9.55+/-69.00, T6 13.67+/-28.70; serine-endopeptidase H1 (nmol/mg creatinine) T0 7.86+/-26.95, T2 17.17+/-59.37, T6 18.19+/- 79.14; and serine-thiol-endopeptidase H2 (nmol/mg creatinine) T0 3.06+/-21.97, T2 12.06+/-32.42, T6 16.22+/- 44.06. Thirty other healthy children matched for age and gender were considered as a control group. This group was assessed once and the results were: NEP-like activity 6.05+/-10.54, ACE 0.11+/-0.22, PE 7.10+/-13.36, H1 5.00+/-17.30, and H2 6.00+/-20.16. In conclusion, we observed that NEP-like and H1 enzymes exhibited significant increased urinary activity 6 months after the diagnosis. This increase occurred in spite of the disappearance of clinical symptoms, which occurred 2 months after the diagnosis. We believe that the increase in urinary enzymatic activity could be a manifestation of a silent tubular dysfunction following an episode of acute post-infectious glomerulonephritis.
Naghettini
A V
AV
Pediatric Nephrology Unit, Department of Pediatrics, Escola Paulista de Medicina, UNIFESP, São Paulo, Brazil. naghetti@ terra.com.br
Nogueira
P C
PC
Juliano
M
M
Bueno
A A
AA
Casarini
D E
DE
de Abreu Carvalhaes
J T
JT
D000208:Acute Disease; D001424:Bacterial Infections / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D010450:Endopeptidases / Q000652:urine*; D005260:Female; D005921:Glomerulonephritis / Q000201:enzymology* / Q000652:urine; D006801:Humans; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000652:urine*; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000652:urine
D010450:Endopeptidases; D007703:Peptidyl-Dipeptidase A; D012697:Serine Endopeptidases; C000705287:PREPL protein, human; D000085822:Prolyl Oligopeptidases