title: Independent associations of urine neutrophil gelatinase-associated lipocalin and serum uric acid with interstitial fibrosis and tubular atrophy in primary glomerulonephritis.
abstract: The degree of interstitial fibrosis and tubular atrophy (IFTA) is one of the strongest prognostic factors in glomerulonephritis (GN). In experimental models, high serum uric acid (UA) could contribute to IFTA through direct effects on the renal tubules, but the significance of this process has not been evaluated in patients. Urine neutrophil gelatinase-associated lipocalin (NGAL) is produced by renal tubules following acute or chronic damage. We investigated the relationship between UA and NGAL excretion in primary GN and tested whether these biomarkers are independently associated with IFTA. Urine and blood were collected from patients on the day of kidney biopsy. IFTA was assessed semi-quantitatively. Fifty-one patients with primary GN were enrolled. NGAL/creatinine correlated significantly with proteinuria but not with glomerular filtration rate (GFR). By contrast, UA correlated with GFR but not with proteinuria. NGAL/creatinine did not correlate with UA. Both NGAL/creatinine and UA increased with the severity of IFTA. By multivariate analysis, GFR, NGAL/creatinine, and UA were independently associated with moderate-to-severe IFTA. Combining UA and NGAL/creatinine with classical predictors (proteinuria and GFR) tended to improve discrimination for moderate-to-severe IFTA. Findings that UA was unrelated to urinary NGAL excretion suggest that the two biomarkers reflect different pathways related to the development of IFTA in primary GN. Both NGAL/creatinine and UA were independently associated with moderate-to-severe IFTA.
authors.affiliation: Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Amornpan
authors.initials: A
authors.lastname: Lertrit
authors.affiliation: Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Suchin
authors.initials: S
authors.lastname: Worawichawong
authors.affiliation: Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Somlak
authors.initials: S
authors.lastname: Vanavanan
authors.affiliation: Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Anchalee
authors.initials: A
authors.lastname: Chittamma
authors.affiliation: Section for Mathematics, Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Phranakhon Si Ayutthaya, Thailand.
authors.forename: Dittapol
authors.initials: D
authors.lastname: Muntham
authors.affiliation: Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Piyanuch
authors.initials: P
authors.lastname: Radinahamed
authors.affiliation: Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Aumporn
authors.initials: A
authors.lastname: Nampoon
authors.affiliation: Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Chagriya
authors.initials: C
authors.lastname: Kitiyakara
keywords: biomarker; fibrosis; glomerulonephritis; kidney; neutrophil gelatinase–associated lipocalin; uric acid