Hypo-Expression of Flice-Inhibitory Protein and Activation of the Caspase-8 Apoptotic Pathways in the Death-Inducing Signaling Complex Due to Ischemia Induced by the Compression of the Asphyxiogenic Tool on the Skin in Hanging Cases

Forensic application of epidermal expression of HSP27 and HSP70 for the determination of wound vitality in human compressed neck skin

Estimating the age and vitality of human skin wounds is essential in forensic practice, and the use of immunohistochemical parameters in this regard remains a challenge. Heat shock proteins (HSPs) are evolutionarily conserved universal proteins that protect biological systems from various types of stress. However, its importance in forensic pathology for determining wound activation in neck compression skin remains unclear. The expression of HSP27 and HSP70 in neck skin samples was immunohistochemically examined to understand its forensic applicability in determining wound vitality. Skin samples were obtained from 45 cases of neck compression (hanging, 32 cases; strangulation, 10 cases; manual strangulation, 2 cases; other, 1 case) during forensic autopsies; intact skin from the same individual was used as a control. HSP27 expression was detected in 17.4% of keratinocytes in the intact skin samples. In the compressed region, the frequency of HSP27 expression in keratinocytes was 75.8%, which was significantly higher than that in intact skin. Similarly, HSP70 expression was 24.8% in intact skin samples and 81.9% in compressed skin samples, significantly higher in compressed skin than in intact skin samples. This increase in case compression cases may be due to the cell defence role of HSPs. From a forensic pathology perspective, the immunohistochemical examination of HSP27 and HSP70 expression in neck skin could be considered a valuable marker for diagnosing traces of antemortem compression.

FOXO3 Depletion as a Marker of Compression-Induced Apoptosis in the Ligature Mark: An Immunohistochemical Study

One of the most challenging issues in forensic pathology is lesion vitality demonstration, particularly in cases of hanging. Over the past few years, immunohistochemistry has been applied to this field with promising results. In particular, protein and transcription factors involved in the apoptotic process have been studied as vitality markers for the ligature mark. This study represents an implementation of our previous studies on ligature mark vitality demonstration. In this study, we evaluated the FOXO3 expression in post-mortem cervical skin samples through an immunohistochemical analysis. To evaluate FOXO3 expression, anti-FOXO3 antibodies (GTX100277) were used. The study group comprised 21 cases, 8 women and 13 men, whereas the control group consisted of 13 cases of subjects who died due to other causes. Decomposition and no clear circumstantial data were exclusion criteria. We found that FOXO3 is decreased in hanging cases compared with normal skin in other causes of death (p-value < 0.05). No differences were seen concerning the type of hanging material (hard or soft), type of hanging (complete or incomplete), and position of the knot. Our results suggest that FOXO3 depletion could be a valid immunohistochemical marker of ligature mark vitality.

State-of-the-Art on Wound Vitality Evaluation: A Systematic Review

The vitality demonstration refers to determining if an injury has been caused ante- or post-mortem, while wound age means to evaluate how long a subject has survived after the infliction of an injury. Histology alone is not enough to prove the vitality of a lesion. Recently, immunohistochemistry, biochemistry, and molecular biology have been introduced in the field of lesions vitality and age demonstration. The study was conducted according to the preferred reporting items for systematic review (PRISMA) protocol. The search terms were "wound", "lesion", "vitality", "evaluation", "immunohistochemistry", "proteins", "electrolytes", "mRNAs", and "miRNAs" in the title, abstract, and keywords. This evaluation left 137 scientific papers. This review aimed to collect all the knowledge on vital wound demonstration and provide a temporal distribution of the methods currently available, in order to determine the age of lesions, thus helping forensic pathologists in finding a way through the tangled jungle of wound vitality evaluation.

Forensic Application of Epidermal Ubiquitin Expression to Determination of Wound Vitality in Human Compressed Neck Skin

Ubiquitin is a member of the heat shock protein family and is rapidly induced by various types of stimuli, including ischemic and mechanical stress. However, its significance in determining wound vitality of neck compression skin in forensic pathology remains unclear. We immunohistochemically examined the expression of ubiquitin in the neck skin samples to understand its forensic applicability in determining wound vitality. Skin samples were obtained from 53 cases of neck compression (hanging, 42 cases; strangulation, 11 cases) during forensic autopsies. Intact skin from the same individual was used as the control. Ubiquitin expression was detected in 73.9% of keratinocytes in intact skin samples, but only in 21.2% of keratinocytes in the compression regions, with statistical differences between the control and compression groups. This depletion in the case of neck compression may be caused by the impaired conversion of conjugated to free ubiquitin and failure of de novo ubiquitin synthesis. From a forensic pathological perspective, immunohistochemical examination of ubiquitin expression in the skin of the neck can be regarded as a valuable marker for diagnosing traces of antemortem compression.

A Clue on the Skin: A Systematic Review on Immunohistochemical Analyses of the Ligature Mark

BACKGROUND

A ligature mark is a common injury in cases of hanging or strangulation. Estimation of age and vitality of the ligature mark can be crucial for differentiating antemortem and postmortem wounds and to distinguish between simulated suicidal hanging or accidental strangulation to conceal a crime and not simulated events. The immunohistochemistry has been recommended by several Authors as a reliable tool to determine whether an injury was sustained during life or not. Unfortunately, no general agreement on the immunohistochemical markers to be used has been found among the scientific community. The aim of the study was to detect the type and function of the immunohistochemical markers useful in the assessment of the vitality and age of the ligature marks for routine diagnostics.

METHODS

Papers available on Pubmed, Scopus, and Web of Science were reviewed according to the PRISMA statement.

RESULTS

Only eight papers satisfied all the following inclusion criteria: full texts in English dealing with human ligature marks and immunohistochemistry published on impacted or indexed scientific journals.

CONCLUSIONS

The assessment of the vitality of a ligature mark is still a challenging topic in forensic science. Under ideal conditions and in compliance with autopsy protocols, the diagnosis of death by hanging or strangulation on fresh bodies can be better supported by autopsy findings other than a ligature mark. The validation of immunohistochemical markers on large series could be of help in doubtful cases and differential diagnoses.

An Overview on Actual Knowledge About Immunohistochemical and Molecular Features of Vitality, Focusing on the Growing Evidence and Analysis to Distinguish Between Suicidal and Simulated Hanging

In forensic practice, the pathologist is often asked to determine whether a hanging was committed as suicide or as a simulated hanging (when a dead body is suspended after death). When exterior evidence of violence is absent and the crime scene investigation fails to identify useful proof, it is nearly impossible to tell whether the dead body was suspended or not. As a result, determining whether the ligature mark was created during life or not should rely on the research and demonstration of vital reactions on the ligature mark. The main purpose of this review article is to provide a summary of current knowledge about the histological and immunohistochemical characteristics of vitality in hanging. The authors also aim to identify the most significant vitality markers on ligature marks for further scientific validation and to propose a standardized diagnostic protocol for hanging. The study was conducted according to the Preferred Reporting Items for Systematic Review (PRISMA) Protocol. Relevant scientific papers were found from PubMed up to April 2021, using the following keywords: hanging AND skin AND vitality. Three main points were studied: ligature mark dehydration, immunological response to mechanical injury, and apoptosis induction as a result of the previous points. An increase in apoptosis is evident in the ligature mark (due to physical and chemical processes involved), as demonstrated by FLICE-inhibitory protein (FLIP) depletion. Immunohistochemical detection of Aquaporin 3 (AQP3) and increase in the concentration of different electrolytes rely solely on ligature mark dehydration. Also, microRNAs (MiRNAs) could become reliable forensic biomarkers for ligature mark vitality diagnosis in the near future. To ensure high reliability in court cases, forensic investigation in hanging should rely on modern and proven markers, even a mix of several markers.