The forensic evaluation of deaths due to violent mechanical asphyxia recognizes a diagnostic difficulty since almost all the signs detected in asphyxial deaths can be found in other types of deaths, or the signs attributable to the means can be extremely subtle. Furthermore, in the event of a sudden total interruption of the flow of oxygen within the respiratory tract, in case of very rapid death or in the event that reflex mechanisms occur (cardiac or nervous), autopsy findings may also be absent or very vague. In asphyxial deaths, histological investigations often show not pathognomonic findings and their diagnostic value is widely debated. Therefore, in cases where histological investigations do not provide conclusive indications regarding the cause of death, the use of immunohistochemical investigations is of fundamental utility. The present study aims to evaluate, through immunohistochemical analysis, the presence of molecular markers in lung tissue, in subjects who died for violent mechanical asphyxia, comparing them with control cases, selected among subjects who died suddenly from a non-asphyxial cause. Some markers, already validated in human use, were tested on selected tissues as they were deemed useful to give indications on the biochemical pathways activated following hypoxia. 28 cases (Group 1) of subjects who died following violent mechanical asphyxia, with different modalities, and 10 controls (Group 2) who died suddenly from non-asphyxial causes, were selected. All subjects (Group 1 and 2) underwent external cadaveric examination, autopsy and subsequent histological and toxicological investigations. The lung tissue preparations were subjected to immunohistochemical investigation, looking for the following markers: HIF1α, VEGF, iNOS, NOX2, P2X7 and A2A. All preparations were read at the same magnification and evaluated for immunohistochemical labeling positivity by two different blinded raters, using a semiquantitative method. Data were checked for normality and analyzed using a two-tailed unpaired t-test. The results of the comparisons between the two groups (Group 1 and Group2) showed a statistically significant difference for all markers tested (p-value <0.05). The present study therefore highlights the positive impact of the immunohistochemical method in the diagnosis of violent mechanical asphyxia in the forensic field on human samples. In particular, the markers tested proved to be valid in the laboratory study of asphyxial deaths, being able to constitute a useful panel for the forensic pathologist who approaches this type of death.
La valutazione medico legale dell’asfissia meccanica violenta riconosce una difficoltà diagnostica poiché, quasi tutti i segni rilevati nelle morti asfittiche, possono essere riscontrabili in altre tipologie di decessi o possono essere estremamente sfumati i segni riconducibili al mezzo. Inoltre, in caso di improvvisa interruzione totale del flusso di ossigeno e decorso molto rapido o a seguito dell’instaurarsi di meccanismi cardiaci o nervosi riflessi, anche i reperti autoptici possono essere assenti o molto sfumati. Nelle morti asfittiche le indagini istologiche mostrano spesso reperti non univoci e il loro valore diagnostico risulta ampiamente dibattuto. Dunque, nei casi in cui le indagini istologiche non forniscano indicazioni conclusive relativamente alla causa del decesso, il ricorso alle indagini immunoistochimiche risulta di fondamentale utilità. Il presente studio si pone l’obiettivo di valutare, mediante analisi immunoistochimica, la presenza di marcatori molecolari presenti a carico del tessuto polmonare, in soggetti deceduti a seguito di asfissia meccanica violenta, confrontandoli con controlli selezionati tra soggetti deceduti repentinamente per causa non asfittica. Sono stati, quindi, analizzati alcuni marcatori, già validati nell’utilizzo umano, che si ritiene possano, meglio di altri, dare indicazioni sulle vie biochimiche attivate a seguito di ipossia. Sono stati selezionati 28 casi (Gruppo 1) di soggetti deceduti a seguito di asfissia meccanica violenta, con diverse modalità, e 10 controlli (Gruppo 2) deceduti repentinamente per causa non asfittica. Tutti i soggetti (Gruppo 1 e 2) sono stati sottoposti a ricognizione cadaverica esterna, autopsia e successive indagini istologiche e tossicologiche. I preparati tissutali polmonari sono stati sottoposti ad indagine immunoistochimica, ricercando i seguenti marcatori: HIF1α, VEGF, iNOS, NOX2, P2X7 e A2A. Tutti i preparati sono stati letti al medesimo ingrandimento e valutati per la positività alla marcatura immunoistochimica da due diversi valutatori in cieco, utilizzando un metodo semiquantitativo. I dati sono stati controllati per verificarne la normalità e analizzati utilizzando un T-test non appaiato a due code. I risultati dei confronti tra i due gruppi (Gruppo 1 e Gruppo2) hanno mostrato una differenza statisticamente significativa per tutti i marcatori testati (p-value <0.05). Il presente studio evidenzia, quindi, l'impatto positivo della metodica immunoistochimica nella diagnosi delle asfissie meccaniche violente in ambito forense su campione umano. In particolare i markers testati si sono rivelati validi nello studio laboratoristico delle morti asfittiche, potendo costituire un pannello di utilità per il patologo forense che approcci tale tipo di decesso.
Asfissia meccanica violenta: studio di marcatori immunoistochimici su campioni umani per l’applicazione in ambito forense
ALFIERI, Letizia
2024
Abstract
The forensic evaluation of deaths due to violent mechanical asphyxia recognizes a diagnostic difficulty since almost all the signs detected in asphyxial deaths can be found in other types of deaths, or the signs attributable to the means can be extremely subtle. Furthermore, in the event of a sudden total interruption of the flow of oxygen within the respiratory tract, in case of very rapid death or in the event that reflex mechanisms occur (cardiac or nervous), autopsy findings may also be absent or very vague. In asphyxial deaths, histological investigations often show not pathognomonic findings and their diagnostic value is widely debated. Therefore, in cases where histological investigations do not provide conclusive indications regarding the cause of death, the use of immunohistochemical investigations is of fundamental utility. The present study aims to evaluate, through immunohistochemical analysis, the presence of molecular markers in lung tissue, in subjects who died for violent mechanical asphyxia, comparing them with control cases, selected among subjects who died suddenly from a non-asphyxial cause. Some markers, already validated in human use, were tested on selected tissues as they were deemed useful to give indications on the biochemical pathways activated following hypoxia. 28 cases (Group 1) of subjects who died following violent mechanical asphyxia, with different modalities, and 10 controls (Group 2) who died suddenly from non-asphyxial causes, were selected. All subjects (Group 1 and 2) underwent external cadaveric examination, autopsy and subsequent histological and toxicological investigations. The lung tissue preparations were subjected to immunohistochemical investigation, looking for the following markers: HIF1α, VEGF, iNOS, NOX2, P2X7 and A2A. All preparations were read at the same magnification and evaluated for immunohistochemical labeling positivity by two different blinded raters, using a semiquantitative method. Data were checked for normality and analyzed using a two-tailed unpaired t-test. The results of the comparisons between the two groups (Group 1 and Group2) showed a statistically significant difference for all markers tested (p-value <0.05). The present study therefore highlights the positive impact of the immunohistochemical method in the diagnosis of violent mechanical asphyxia in the forensic field on human samples. In particular, the markers tested proved to be valid in the laboratory study of asphyxial deaths, being able to constitute a useful panel for the forensic pathologist who approaches this type of death.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
