The role of advanced oxidation protein products in intensive care unit patients with acute kidney injury ☆ Paolo Lentini MD a,c, ⁎ , Massimo de Cal BS a,c , Dinna Cruz MD a , Alexandra Chronopoulos MD a , Sachin Soni MD a , Federico Nalesso MD a , Monica Zanella MD a , Francesco Garzotto M.Eng a , Alessandra Brendolan MD a , Pasquale Piccinni MD b , Claudio Ronco MD a a Department of Nephrology, Dialysis and Transplantation, St. Bortolo Hospital, 36100 Vicenza, Italy b Intensive Care Unit, St. Bortolo Hospital, 36100 Vicenza, Italy c Division of Nephrology, Department of Medical and Surgical Sciences, University of Padua, Italy Keywords: AKI; ICU; OS; AOPP Abstract Introduction: Oxidative stress (OS) is an imbalance between the production of oxidizing chemical species and the antioxidant defense. It is known that OS increases in critically ill patients with acute kidney injury (AKI). Measurement of advanced oxidation protein products (AOPPs) has been found to be a simple tool for monitoring OS. Aims: The aims of this study were to evaluate OS in intensive care unit (ICU) patients by AOPP levels and compare its levels between patients with and without AKI; we also wanted to assess the ability of AOPP to predict the development of AKI in this population. Patients, Material, and Methods: We performed a prospective cohort study to compare AOPP levels between critically ill AKI (as defined by Risk-Injury-Failure-Loss-End Stage Renal Disease [RIFLE] criteria) and non-AKI patients. Blood samples were collected from all consecutively admitted patients upon arrival to ICU and daily for up to 4 days. We collected 234 blood samples from 86 adult medical and surgical ICU patients. The levels of AOPP were determined in the plasma and measured by spectrophotometry at 340 nm and compared between non-AKI (n = 71) and AKI patients (n = 15). We further subdivided the AKI patients according to severity of AKI (worst RIFLE class attained in ICU). Results: Among the 86 patients, 15 (17.44%) developed AKI during their stay in ICU, whereas 71 patients (82.56%) did not. Among the AKI patients, 5 had AKI on ICU admission, whereas 10 developed it later. The levels of AOPP were significantly higher among AKI patients compared with non-AKI patients (153.8 ± 117.8 versus 129.0 ± 114.9 μmol/L, respectively; P = .034). Patients with the most severe AKI (RIFLE class Failure) had markedly elevated AOPP levels compared with RIFLE class Risk and Injury patients (P = .012). Abbreviations: AKI, acute kidney injury; ICU, intensive care unit; OS, oxidative stress; AOPP, advanced oxidation protein products; ROS, reactive oxygen species. ☆ All authors equally contributed to this study. ⁎ Corresponding author. Tel.: +39 0444 753650; fax: +39 0444 753949. E-mail address: paolo.lentini@yahoo.it (P. Lentini). 0883-9441/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jcrc.2010.04.006 Journal of Critical Care (2010) 25, 605–609