Changes in Urinary Nitric Oxide in Pediatric Renal Diseases

ABSTRACT

PURPOSE: Nitric oxide(NO) is a very potent vasodilator synthesized from L-arginine by endothelial cells. We investigated whether urinary NO excretion was altered in various renal diseases in children and whether urinary NO excretion could be used in predicting pathologic causes and fibrosis in renal diseases in children. METHODS: We recruited 48 patients(32 minimal change nephrotic syndrome[MCNS] and 16 vesicoureteral reflux[VUR] patients) from the pediatric renal clinic in Korea University Guro Hospital. We measured the concentration of nitrite(NO2) and nitrate(NO3) by Griess reaction and that of creatinine(Cr) by Jaffe method in randomized spot urines. We then analyzed the urinary(NO2+NO3)/Cr ratios and compared the values between each patient group. Urinary (NO2+NO3)/Cr ratios were also evaluated according to the recurrence and the degree of proteinuria at sampling in the MCNS group and compared according to the presence of renal scarring and the grade of reflux in the VUR group. RESULTS: The ratios of urinary(NO2+NO3)/Cr were significantly increased in the VUR and MCNS groups, as compared to the control group. In the MCNS group, a higher level of urine (NO2+NO3)/Cr was observed in frequent relapse patients(relapse over four times within one year after first diagnosis) and the patients with severe proteinuria at sampling, respectively. The VUR group with renal scars also showed a higher level of urinary(NO2+NO3)/Cr compared to that without scars. CONCLUSIONS: In summary, NO may play a role in the pathogenesis of VUR and MCNS. NO also seems to affect proteinuria and renal scar formation.