RT Journal Article SR Electronic T1 Urinary Metabolomics from a Dose-Fractionated Polymyxin B Rat Model of Acute Kidney Injury JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.05.21.444980 DO 10.1101/2021.05.21.444980 A1 Emanuela Locci A1 Jiajun Liu A1 Gwendolyn M. Pais A1 Alberto Chighine A1 Dariusc Andrea Kahnamoei A1 Theodoros Xanthos A1 Athanasios Chalkias A1 Andrew Lee A1 Alan R. Hauser A1 Jack Chang A1 Nathaniel J. Rhodes A1 Ernesto d’Aloja A1 Marc H. Scheetz YR 2021 UL http://biorxiv.org/content/early/2021/05/22/2021.05.21.444980.abstract AB Background Polymyxin B remains an important antimicrobial against multi-drug resistant bacteria; however, kidney injury is often a treatment limiting event with kidney failure rates that range from 5-13%.Methods Samples were obtained from a previously conducted study of male Sprague-Dawley rats that received dose fractionated polymyxin B (12 mg/kg/day subcutaneously) once daily (QD), twice daily (BID), and thrice daily (TID) for three days. In the original study, urinary biomarkers and kidney histopathology scores were determined. Urine was sampled daily and analyzed for urinary metabolites via 1H NMR analysis.Unsupervised Principal Components Analysis was applied for exploratory data analysis to identify trends and outliers in the spectral data. Then, supervised Orthogonal Partial Least Square Discriminant Analysis was applied to classify the samples collected in different days and identify metabolic differences during the treatment. Metabolomes were compared across study groups (i.e. those receiving QD, BID, TID, and control) using a mixed-effects models. Spearman correlation was performed for injury biomarkers and the metabolome.Results A total of 27 rats contributed 77 urinary samples; n=25 rats were included that were treated with Polymyxin B and n=2 received saline. Pre-dosing samples clustered well and were characterized by higher amounts of citrate, 2-oxoglutarate, and Hippurate. On day 1 post treatment, day 1 samples showed higher taurine; day 3 samples had higher lactate, acetate and creatine. Taurine was the only metabolite significantly increased in both BID and TID compared to QD group. Taurine on day 1 correlated with increasing histopathology scores (Spearman’s rho = 0.4167, P=0.038) and KIM-1 (Spearman’s rho =0.4052, P=0.036); whereas KIM-1 on day one and day 3 did not reach significance with histopathology (Spearman’s rho = 0.3248, P=0.11 and Spearman’s rho = 0.3739, P=0.066).Conclusion Polymyxin B causes increased amounts of urinary taurine on day 1 which then normalizes to baseline concentrations. Taurine may provide one of the earlier signals of acute kidney damage caused by polymyxin B.Competing Interest StatementThe authors have declared no competing interest.