BACKGROUND: The distinction between monomeric human neutrophil lipocalin/neutrophil gelatinase-associated lipocalin (HNL/NGAL), secreted by injured kidney tubular cells, and dimeric HNL/NGAL, released by activated neutrophils, is important to accurately diagnose acute kidney injury (AKI). METHODS: 132 urine samples from 44 intensive care unit (ICU) patients and five urine samples from non-ICU patients with urinary tract infections (UTIs) were analyzed by two monoclonal enzyme-linked immunosorbent assays (ELISA-1 and ELISA-2). The presence of monomeric and/or dimeric HNL/NGAL in each sample was visualized by Western blotting. RESULTS: The ELISA-1 detected both monomeric and dimeric HNL/NGAL whereas the ELISA-2 almost exclusively detected dimeric HNL/NGAL with an area under the receiver-operating characteristics curve (AuROC) of 0.90. The ELISA-1/ELISA-2 ratio detected the monomeric form with an AuROC of 0.92. In 32 AKI patients, dimer-specific ELISA-2 levels decreased pre-AKI whereas the monomer-specific ELISA-1/ELISA-2 ratio gradually increased beyond AKI diagnosis. High ELISA-2 levels and/or low ELISA-1/ELISA-2 ratios detected a predominance of dimeric HNL/NGAL in urine from the patients with UTIs. CONCLUSIONS: In combination, our two ELISAs distinguish monomeric HNL/NGAL, produced by the kidney epithelium, from dimeric HNL/NGAL, released by neutrophils during AKI development, as well as reduce the confounding effect of neutrophil involvement when bacteriuria is present.
BACKGROUND: The distinction between monomeric human neutrophil lipocalin/neutrophil gelatinase-associated lipocalin (HNL/NGAL), secreted by injured kidney tubular cells, and dimeric HNL/NGAL, released by activated neutrophils, is important to accurately diagnose acute kidney injury (AKI). METHODS: 132 urine samples from 44 intensive care unit (ICU) patients and five urine samples from non-ICU patients with urinary tract infections (UTIs) were analyzed by two monoclonal enzyme-linked immunosorbent assays (ELISA-1 and ELISA-2). The presence of monomeric and/or dimeric HNL/NGAL in each sample was visualized by Western blotting. RESULTS: The ELISA-1 detected both monomeric and dimeric HNL/NGAL whereas the ELISA-2 almost exclusively detected dimeric HNL/NGAL with an area under the receiver-operating characteristics curve (AuROC) of 0.90. The ELISA-1/ELISA-2 ratio detected the monomeric form with an AuROC of 0.92. In 32 AKI patients, dimer-specific ELISA-2 levels decreased pre-AKI whereas the monomer-specific ELISA-1/ELISA-2 ratio gradually increased beyond AKI diagnosis. High ELISA-2 levels and/or low ELISA-1/ELISA-2 ratios detected a predominance of dimeric HNL/NGAL in urine from the patients with UTIs. CONCLUSIONS: In combination, our two ELISAs distinguish monomeric HNL/NGAL, produced by the kidney epithelium, from dimeric HNL/NGAL, released by neutrophils during AKI development, as well as reduce the confounding effect of neutrophil involvement when bacteriuria is present.
Authors: Søren Lindberg; Jan S Jensen; Søren Hoffmann; Allan Z Iversen; Sune H Pedersen; Tor Biering-Sørensen; Søren Galatius; Allan Flyvbjerg; Rasmus Mogelvang; Nils E Magnusson Journal: Cardiorenal Med Date: 2016-02-25 Impact factor: 2.041
Authors: Kathleen D Liu; Wei Yang; Alan S Go; Amanda H Anderson; Harold I Feldman; Michael J Fischer; Jiang He; Radhakrishna R Kallem; John W Kusek; Stephen R Master; Edgar R Miller; Sylvia E Rosas; Susan Steigerwalt; Kaixiang Tao; Matthew R Weir; Chi-Yuan Hsu Journal: Am J Kidney Dis Date: 2014-10-11 Impact factor: 8.860
Authors: Rinaldo Bellomo; John A Kellum; Claudio Ronco; Ron Wald; Johan Martensson; Matthew Maiden; Sean M Bagshaw; Neil J Glassford; Yugeesh Lankadeva; Suvi T Vaara; Antoine Schneider Journal: Intensive Care Med Date: 2017-03-31 Impact factor: 17.440
Authors: E Singer; L Markó; N Paragas; J Barasch; D Dragun; D N Müller; K Budde; K M Schmidt-Ott Journal: Acta Physiol (Oxf) Date: 2013-02-04 Impact factor: 6.311