Potential AKI Outcomes Biomarker Identified
Urinary kynurenic acid levels could as a biomarker of risk in patients with acute kidney injury (AKI), as increased levels of the acid were shown to be associated with adverse renal and clinical outcomes in these patients in a recent study.
Early risk stratification is key to improved outcomes in patients with AKI. For this reason, researchers sought to determine whether urine levels of metabolites of a conserved key inflammatory pathway could be used to predict renal outcomes.
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For their study, researchers analyzed data from 112 ICU patients with AKI, with 92 patients eligible following exclusion criteria. Urine samples were collected and mass spectrometry was used to analyze tryptophan levels.
Overall, 67 patients recovered within 7 days of AKI, while 25 had either late recovery or non-recovery (LNR). Urinary concentrations of tryptophan, kynurenine, 3-OH anthranillic acid, serotonine, and kynurenine/tryptophan were significantly lower in LNR patients, while creatinine normalized excretion of kynurenic acid was substantially increased in LNR patients.
Higher kynurenic acid concentrations were associated with longer AKI duration, increased need for renal replacement therapy, and 30-day mortality.
“Increased urinary levels of kynurenic acid, a key inflammatory metabolite of the tryprophan degradation pathway, are associated with adverse renal and clinical outcomes in critically ill patients with AKI. Urinary kynurenic acid may serve as an early risk stratificator in respective patients with AKI.”
—Michael Potts
Reference:
Aregger F, Uehlinger DE, Fusch G, et al. Increased urinary excretion of kynurenic acid is associated with non-recovery from acute kidney injury in critically ill patients [published online February 26, 2018]. BMC Nephrology. https://doi.org/10.1186/s12882-018-0841-5.