Postmortem Interval Estimation: New Approaches by the Analysis of Human Tissues and Microbial Communities’ Changes

Abstract

There are several methodologies available to estimate time since death based on different changes that a corpse undergoes after death. However, these methods are imprecise due to the decomposition process being affected by several factors, principally temperature and humidity. Current trends for the determination of the Postmortem Interval (PMI) attempt to estimate the PMI in a quantifiable manner, based on chemical changes on and in the body, summarized in the field of “thanatochemistry”. Although these methodologies have improved PMI estimates, additional research has been developed to increase the accuracy and precision of this determination. As a result, the fields of “thanatobiology” and “thanatomicrobiome” have emerged. Thanatobiology is based on the estimation of the PMI from DNA/RNA degradation, signaling pathways of cell death, and protein analysis. Thanatomicrobiome refers to changes in the bacterial communities as a consequence of the decomposition process. Although both approaches seem to improve PMI estimates, applications of thanatobiology methodologies are more appropriate in the first phases of decomposition, while thanatomicrobiome analyses are applicable in advanced stages. Further research is needed in these new fields in order to establish their applicability in forensic cases. This is a review of the current state-of-the-art methodology in these two subfields.

Post-Mortem Interval and Microbiome Analysis through 16S rRNA Analysis: A Systematic Review

“…Being a dynamic entity, human microbiota undergoes important changes during human life in response to numerous environmental and individual factors, as for example smoking habits, drug treatments, diet and healthcare status [ 24 , 25 , 26 ]. The spectrum of ways that microbiome could be used is wide [ 27 , 28 , 29 , 30 , 31 , 32 ]. From this point of view, microbiota can be defined as a meta-organ, i.e., a structure that is anatomically not part of our organism, but which, having evolved with man, takes part in it and is fundamental for its correct physiology in life, possibly playing a role in the post-mortem decomposition stages and PMI estimation [ 33 ].…”

The Influence of Eyelid Position and Environmental Conditions on the Corneal Changes in Early Postmortem Interval: A Prospective, Multicentric OCT Study

“…Consequently, forensic research on the eye in postmortem intervals focused almost exclusively on the biochemical alterations affecting the aqueous and vitreous [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

Proteomics: A New Research Frontier in Forensic Pathology

“…Human samples, including blood, hair, bone, and fingernails, have been subject to proteomic analyses in recent years [ 1 ]. However, the application of forensic proteomics may run into obstacles, such as unidentified samples and contaminants [ 2 ]. Moreover, specific procedures are necessary when preparing a sample, which limits the generalized use of proteomic analysis in forensics.…”

“…Moreover, specific procedures are necessary when preparing a sample, which limits the generalized use of proteomic analysis in forensics. The advantage of proteomics lies in its ability to provide a more comprehensive overview of a sample than genomic analysis [ 2 ]. In addition, proteomics is an excellent option when nucleic acids are missing or deteriorated [ 2 ].…”

“…The advantage of proteomics lies in its ability to provide a more comprehensive overview of a sample than genomic analysis [ 2 ]. In addition, proteomics is an excellent option when nucleic acids are missing or deteriorated [ 2 ]. Thus, when DNA is unattainable, ambiguous, or non-existent, proteomics serves as a viable alternative forensic method [ 3 ].…”