Forensic Metabolomics: Enhancing PMI Estimation through Porcine Bone Tissue Profiling

The estimation of
the post-mortem interval (PMI) in forensic
skeletal
remains is extremely challenging, as traditional morphological methods
lose their effectiveness and accuracy as decomposition progresses.
To address this issue, this study utilizes metabolomics to investigate
the biochemical changes affecting bone tissue during the decomposition
process. Fragments of pig mandibles were buried in an open grassland
field at varying depths (0, 10, 30, and 50 cm) and collected every
month up to 6 months. Bone metabolites were extracted using a single-phase
methanol–water protocol, and both gas chromatography–mass
spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry
(LC-MS/MS) were applied for their analysis. The primary goal of this
study is to identify specific metabolic shifts associated with increasing
post-mortem intervals to identify potential bone metabolomic biomarkers
for PMI and to assess the impact of burial depth on these changes.
The generated regression models using LC-MS/MS data were able to estimate
the PMI of the skeletal fragments with an accuracy of 14 days over
6 months, an outstanding result, particularly considering the current
lack of methodologies to estimate PMI from bones. Burial depth, instead,
did not play a significant role on the metabolomic bone signature.
This research deepens our understanding of post-mortem biochemical
processes in bones, making a significant contribution to the advancing
field of forensic metabolomics, and highlights the potential of metabolomics
for investigating buried skeletal remains and enhancing post-mortem
interval assessments.