Effects of intra- and post-operative ischemia on the metabolic profile of clinical liver tissue specimens monitored by NMR.
Metabolomic profiles of tissues could greatly contribute to advancements in personalized medicine but are influenced by differences in adopted preanalytical procedures; nonhomogeneous pre- and post-excision ischemia times are potential sources of variability. In this study, we monitored the impact of ischemia on the metabolic profiles, acquired with high-resolution magic-angle-spinning (1)H NMR, of 162 human liver samples collected during and up to 6 h after routine surgery. The profiles changed significantly as a function of intraoperative warm ischemia (WI) and postresection cold ischemia (CI) time, with significant variations in the concentration of the same 16 metabolites. Therefore, a tight control of the preanalytical phase is essential for reliable metabolomic analyses of liver diseases. The NMR profiles provide a reliable "fingerprint" of ischemia and have predictive value: the best-performing predictive models are found to discriminate extreme time points of CI (0' vs 360 ') in the training set with cross-validation accuracy of ~90%; samples in the validation cohort can discriminate short (≤60') from long (≥180') CI with an accuracy of ~80%. For WI, the corresponding figures are 95.6 and 92%, respectively. Therefore, ischemia NMR profiles might become a tool for tissue quality control in biobanks.