AH NMR metabolomic approach for the estimation of the time since death using aqueous humour: an animal model.

Abstract

INTRODUCTION: The estimation of the time since death, or post-mortem interval (PMI), still remains a main conundrum in forensic science. Several approaches have been so far proposed from either a qualitative or a quantitative point of view, but they still lack reliability and robustness. Recently, metabolomics has shown to be a potential tool to investigate the time-related post-mortem metabolite modifications in animal models. OBJECTIVES: Here we propose, for the first time, the use of aH NMR metabolomic approach for the estimation of PMI from aqueous humour (AH) in an ovine model. METHODS: AH samples were collected at different times after death (from 118 to 1429&#xa0;min).H NMR experiments were performed and spectral data analysed by multivariate statistical tools. RESULTS: A multivariate calibration model was built to estimate PMI on the basis of the metabolite content of the samples. The model was validated with an independent test set, obtaining a prediction error of 59&#xa0;min for PMI <&#x2009;500&#xa0;min, 104&#xa0;min for PMI from 500 to 1000&#xa0;min, and 118&#xa0;min for PMI >&#x2009;1000&#xa0;min. Moreover, the metabolomic approach suggested a picture of the mechanisms underlying the post-mortem biological modifications, highlighting the role played by taurine, choline, and succinate. CONCLUSION: The time-related modifications of theH NMR AH metabolomic profile seem to be encouraging in addressing the issue of a reproducible and robust model to be employed for the estimation of the time since death.