title: Urinary N-acetyl-β-D glucosaminidase as a surrogate marker for renal function in autosomal dominant polycystic kidney disease: 1 year prospective cohort study.
abstract: BACKGROUND
  Renal failure is one of the most serious complications associated with autosomal dominant polycystic kidney disease (ADPKD). To date, early markers have failed to predict renal function deterioration at the early stages. This 1-year prospective study evaluated N-acetyl-β-D-glucosaminidase (NAG) as a new surrogate marker for renal function in ADPKD.
  
  
  METHODS
  A total of 270 patients were enrolled in the study, and we measured urinary NAG, β2-microglobulin, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) prospectively for 1 year to compare their predictive values for renal function.
  
  
  RESULTS
  Baseline urinary NAG/Cr was negatively correlated with estimated glomerular filtration rate (GFR) (r2 = 0.153, P < 0.001) and positively correlated with total kidney volume (TKV) (r2 = 0.113, P < 0.001). Among other biomarkers, urinary NAG/Cr better discriminated patients with decreased renal function from those with conserved renal function, showing the largest area under the curve (AUC 0.794). Immunohistochemical study revealed strong staining along the cyst-lining epithelial cells as well as the nearby compressed tubular epithelial cells. However, both single and repeated measurements of urinary NAG/Cr failed to predict renal function decline in 1 year.
  
  
  CONCLUSIONS
  Urinary NAG/Cr may be a useful surrogate marker for renal function in ADPKD patients.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-Ro Jongno-Gu, Seoul, 110-744, South Korea.
authors.forename: Hayne Cho
authors.initials: HC
authors.lastname: Park
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Hwang
authors.forename: Ah-Young
authors.initials: AY
authors.lastname: Kang
authors.forename: Han
authors.initials: H
authors.lastname: Ro
authors.forename: Myung-Gyu
authors.initials: MG
authors.lastname: Kim
authors.forename: Jung Nam
authors.initials: JN
authors.lastname: An
authors.forename: Ji
authors.initials: J
authors.lastname: In Park
authors.forename: Seung Hyup
authors.initials: SH
authors.lastname: Kim
authors.forename: Jaeseok
authors.initials: J
authors.lastname: Yang
authors.forename: Yun Kyu
authors.initials: YK
authors.lastname: Oh
authors.forename: Kook-Hwan
authors.initials: KH
authors.lastname: Oh
authors.forename: Jung Woo
authors.initials: JW
authors.lastname: Noh
authors.forename: Hae Il
authors.initials: HI
authors.lastname: Cheong
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Hwang
authors.forename: Curie
authors.initials: C
authors.lastname: Ahn
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine*; D000328:Adult; D015415:Biomarkers / Q000652:urine; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007677:Kidney Function Tests / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D008297:Male; D016891:Polycystic Kidney, Autosomal Dominant / Q000175:diagnosis / Q000453:epidemiology* / Q000652:urine*; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D000118:Acetylglucosaminidase