ELISA-measured urinary Klotho as an early biomarker of acute kidney failure in patients undergoing heart surgery or coronary angiography

Introduction and objectives: Acute kidney injury (AKI) is a common complication after cardiac surgery and percutaneous coronary interventions that markedly worsens prognosis. In the last years new early biomarkers for AKI have been identified, but many important aspects still remain to be solved. Klotho is a pleiotropic protein that acts as a paracrine and endocrine hormonal factor in multiple organs. Renal Klotho deficiency has been shown in several AKI animal models. No study has been published in which Klotho was tested in humans as an early biomarker of AKI. The aim of this study was to assess the usefulness of urinary determination of Klotho for the early detection of AKI in patients with acute coronary syndrome or heart failure undergoing cardiac surgery or coronary angiography. Methods: Urinary Klotho was measured 12 hours after intervention in 60 patients admitted to the Intensive Care Unit with acute coronary syndrome or heart failure due to coronary or valvular pathologies, who underwent coronary angiography (30 patients), or cardiac bypass surgery or heart valve replacement (30 patients). The endpoint used for evaluating our patients was the appearance of AKI, in keeping with the RIFLE classification system. Human Klotho levels were measured using an ELISA assay. Results: We found no differences in urinary Klotho levels between patients with AKI and those who did not develop AKI. Moreover, there was no significant correlation between urinary Klotho levels and AKI development. Conclusions: Urinary Klotho measured by ELISA does not seem to be a good candidate to be used as an early biomarker of AKI. (C) 2015 Sociedad Espanola de Nefrologia. Published by ELSEVIER ESPANA, SLU. Published under the terms of the CC BY-NC-ND Licence(http://creativecommons.org/licenses/by-nc-nd/4.0).