The Efficacy of N-acety1-beta-D-glucosaminidase as a Prognostic Factor of Glomerulonephritis

Kim, Beom; Kim, Hye Young; Oh, Dong Jin; Huh, Wooseong; Kim, Yoon Goo; Kim, Dae Joong; Kim, Mi Kyung; Oh, Ha Young

Abstract

BACKGROUNDS: N-acetyl-beta-D-glucosaminidase (NAG) is one of many enzymes that exist in the renal proximal tubular cells. It is said that functional impairment of renal tubule can be detected by checking NAG in the urine. But, it has never been known whether urinary NAG value can be used as a predictor for the prognosis of patients with glomerulonephritis. In this study, we evaluated the relationship between urinary NAG level and the degree of injury in cortical interstitium which has been known to influence the prognosis of renal function in glomerulonephritis closely.
METHODS
Before renal biopsy was performed in each patient, urinary NAG(isoenzyme A and B), urinary beta2-microglobulin, serum blood urea nitrogen (BUN), serum creatinine, serum albumin, creatinine clearance and 24 hour urinary protein excretion were measured. Then, we calculated volume density of cortical interstitium [Vv(i/c)] in each specimen using point count morphometry method after getting a confirmative diagnosis from pathologist. Simple correlation analysis and multivariate regression analysis were carried out.
RESULTS
The number of total patients was 32(male:16), whose median age was 60(32-80). Vv (i/c) had significant correlation with serum creatinine, creatinine clearance and serum BUN. But it was not correlated well with urinary NAG and urinary beta2-microglobulin. Urinary NAG concentration(2.131 2.549unit/mmol Cr) was higher than that of normal control and showed significant correlation with urinary beta2-microglobulin, serum albumin and 24 hour urinary protein excretion in patients.
CONCLUSION
Urinary NAG had no significant correlation with Vv(i/c) that has been known as an important prognostic factor for the renal function in glomerulonephritis, but had significant correlation with urinary protein excretion. We concluded that urinary NAG was not regarded to be an appropriate marker for predicting the prognosis of renal function in patient with glomerulonephritis.