Metabolomics improves the histopathological diagnosis of asphyxial deaths: an animal proof-of-concept model

Abstract

The diagnosis of mechanical asphyxia remains one of the most difficult issues in forensic pathology. Asphyxia ultimately results in cardiac arrest (CA) and, as there are no specific markers, the differential diagnosis of primitive CA and CA secondary to asphyxiation relies on circumstantial details and on the pathologist experience, lacking objective evidence. Histological examination is currently considered the gold standard for CA post-mortem diagnosis. Here we present the comparative results of histopathology versus those previously obtained by 1H nuclear magnetic resonance (NMR) metabolomics in a swine model, originally designed for clinical purposes, exposed to two different CA causes, namely ventricular fibrillation and asphyxia. While heart and brain microscopical analysis could identify the damage induced by CA without providing any additional information on the CA cause, metabolomics allowed the identification of clearly different profiles between the two groups and showed major differences between asphyxiated animals with good and poor outcomes. Minute-by-minute plasma sampling allowed to associate these modifications to the pre-arrest asphyxial phase showing a clear correlation to the cellular effect of mechanical asphyxia reproduced in the experiment. The results suggest that metabolomics provides additional evidence beyond that obtained by histology and immunohistochemistry in the differential diagnosis of CA.

Infant urinary metabolomic profile in a fatal acute methadone intoxication

“…In particular, the 1 H NMR approach allowed not only to strengthen the causal link between methadone blood levels and the acute respiratory failure, but also provided evidence of the asphyxial perturbation on metabolome, independently on its origin. The latter reinforces strong asphyxial evidence on animal models [24,25] and hints its translation on the human model on several biological matrices, towards the implementation of metabolomics as an additional, powerful, diagnostic tool in the forensic scenario.…”

Urinary metabolic modulation in human participants residing in Siachen: a 1H NMR metabolomics approach

“…Itaconate metabolite is derived from TCA cycle intermediate cis-aconiate, which is identified as an anti-inflammatory signal and shown to upregulate cellular antioxidant defences via induction of Nrf2 51 – 54 . During acute settings such as perinatal asphyxia, ischaemia–reperfusion, mechanical asphyxia, there is a complete cut down of oxygen and metabolism is driven towards the TCA cycle to satisfy ATP request 55 – 57 . However, in the case of high-altitude hypoxia, the partial pressure is reduced & during the long-term exposure, body adapts by slowing down the TCA cycle & ATP demand.…”

Letter to the Editor regarding the article ‘ER stress-related protein, CHOP, may serve as a biomarker of mechanical asphyxia: a primary study’ by Hu and colleagues

“…Of greater forensic interest was the second paper published by our group [ 4 ], focused exclusively on the asphyxial phase preceding CA, which describes metabolome modifications according to the animals’ outcome (damage/no damage), providing a comparison with heart and brain histopathology and immunohistochemistry.…”