Postmortem Histopathological, Immunohistochemical, and Genetic Study of Human Lungs and Heart as indicators of mechanical asphyxia.

Background: Forensic pathologists have always had difficulty determining mechanical asphyxia as the cause of death. Biomarkers have been sought to unravel the molecular mechanisms underlying mechanical asphyxia. Aim of the work: was to assess accuracy of postmortem immunohistochemical biomarker CD68 in lung tissues and gene expression of miRNA-3185/ Cytochrome P450 4A11(CYP4A11) in heart tissues as markers in the diagnosis of mechanical asphyxia. Subjects and methods: Forty autopsy cases of both sexes aged between 18 and 56 years old were examined. They included two primary groups: trauma (comparative control) group and mechanical asphyxia group. The lung and heart have been dissected, weighed and subjected to histological, immunohistochemical and genetic examination. Results: There was a markedly significant (p<0.01) reduction in percent area of CD68 expression and number of CD68 positive cells at central zone of the lung of mechanical asphyxia group when compared to trauma group. Regarding miRNA-3185 / CYP4A11 expression, the results showed a substantially significant (p<0.01) rise in miRNA-3185 expression and a highly significant (p<0.01) decline in CYP4A11 expression in cardiac tissues of mechanical asphyxia group in comparison to the trauma group. Conclusion: the high immunohistochemical detection of CD68-positive macrophages in central lung tissue can serve as a potential indication of the absence of mechanical asphyxia. While, Gene expression of miRNA-3185/ CYP4A11 in the heart tissue can be considered a potential marker for mechanical asphyxia. Recommendations: Further studies involving larger sample sizes were needed and be directly utilized in forensic examinations for improved diagnostic accuracy in cases of suspected mechanical asphyxia