Vital reactions - An updated overview

Forensic pilot application of rehydrating solutions on human cadaveric skin: what are the effects on hemorrhagic infiltrates?

The microscopic evaluation of hemorrhagic infiltrates is crucial in forensic diagnostics, but it proves challenging in corificated and mummified cadavers. In these cases, pre-treatment with rehydrating solutions is recommended, although their effects on the hemorrhagic infiltrate are not well understood. In this pilot study, we microscopically investigated the effect of two different rehydrating solutions-Sandison's solution and fabric softener-on well-preserved human cadaveric skin samples taken from areas affected by an ecchymotic lesion, comparing them with direct fixation in formalin. Specifically, we examined the topographic distribution of the hemorrhagic infiltrate in each layer of the skin by assigning a semi-quantitative score, conducted mutual comparisons, and performed statistical analysis. Histologically, compared to direct fixation in formalin, a slight and statistically non-significant reduction in the hemorrhagic infiltrate was observed in samples pre-treated with fabric softener. On the other hand, a more pronounced and statistically significant decrease in scores was observed in samples pre-treated with Sandison's solution. This effect is likely due to the fact that Sandison's solution, due to its components, exerts an osmotic effect, partially inducing osmotic lysis of red blood cells. Overall, extensive areas of hemorrhagic infiltrates were preserved, although to a lesser extent, while smaller foci were markedly reduced, sometimes even disappearing. The findings suggest that Sandison's solution has a detrimental effect on cutaneous hemorrhagic infiltrates, emphasizing the importance of being cautious and conducting dual sampling, using both formalin and a rehydrating solution, for forensic examination of mummified or corificated skin samples.

Skin injuries in forensic histopathology: a descriptive study

Histopathology is commonly used in forensic medicine. Only few studies are available in the literature about the correlation between skin wounds histopathology and survival time or other medicolegal data. The aim of this study was to illustrate the usefulness of histopathological analysis of skin wounds in forensic daily practice and to evaluate its correlation with the clinical and police investigation data. In this single-center, retrospective, and descriptive study, we included 198 forensic pathology cases, from the files of the Legal Medicine and Biopathology Departments of the University Hospital of Nancy, with a total of 554 skin samples. Basing on the police investigations (n = 43), the median survival time between the main related trauma and death was 83 min. The histopathological analysis concluded to 2% of post-mortem lesions (absence of hemorrhage) and 55% of perimortem or undetermined lesions (hemorrhage without inflammation); 8% of the lesions had an estimated time interval between more than 10 min and several hours, 22% between several hours and several days, and 14% between several days and several weeks. Histopathological dating was statistically associated with wound location (p < 0.01), the type of injury, hypothermia, positive toxicology, histopathological hepatic lesions, and survival time (p < 0.001). In conclusion, the histopathological analysis of skin wounds allowed to propose a survival time in almost half of cases, with a significant correlation with the police investigation-based estimation of survival time, but also other parameters such as wound location or toxicology. It however lacks of accuracy, and further studies are needed to develop new markers, notably based on immunohistochemistry.

Identification issues in bodies maimed by train fatalities: The role of the forensic pathologist

Traffic accident injuries are relevant causes of mortality in industrialized countries. Among traffic accidents, the most destructive effect on the victim's body is produced by trains, which in a very short time provoke a complete distortion of the normal anatomical profiles and extensive amputations of the body. Deaths by severe body mutilation and/or decapitation require complex forensic investigation, as the victims' identification and the recognition of their body are not often feasible. In this study, a retrospective analysis of a series of cases of railway accidents is presented, with the aim of showing potential identification strategies, including a systematic physical re-assembling of the body. Among the railway fatalities assessed at the University Institute of Legal Medicine of Milan from 2016 until 2020, 61 cases were analyzed, focusing on the collection of postmortem data to improve accuracy for the identification of the victims. The results showed that the identification could be based on elements traditionally called "secondary identifiers" which, however, are becoming more and more important for positive identification, especially when dealing with migrants, vagrants, and homeless people. However, several issues need to be considered such as the limitations of the public prosecutors to perform expensive analyses (i.e., genetic testing), and the lack of antemortem data to be compared with postmortem findings, both odontological and fingerprint. In cases where it is not possible to proceed with identification or formal recognition of victims of railroad accidents with severe mutilations, a systematic physical re-assembling of the body is critical to reaching positive identification.

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.

Vitality markers in forensic investigations: a literature review

Determining whether an injury was sustained in life or not is one of the most important topics in forensic medicine. Morphological, cytological, and biological techniques are used to assess wound vitality. Several markers involved in vital and supravital reactions increase the accuracy of wound age estimation. This systematic review aimed to investigate the main vitality markers used in forensic medicine to date. This review was conducted by performing a systematic literature search on online resources (PubMed Central database and Google Scholar) until May 2022. We identified 46 articles published between 1987 and May 2022, analyzing a total of 53 markers. Based on the data of this review, the most studied vitality markers were adhesion molecules (fibronectin, p-selectin, CD 15), pro-inflammatory cytokines (IL-6, IL-1β, TNF-α), cathepsin D, tryptase, and microRNAs (miRNAs). The most interesting studies were based on animal models: the different markers were investigated through immunohistochemical and qRT-PCR methods. The experimental methods were usually based on skin incisions, ligature marks, and burned skin areas. To date, it has not been possible to identify any gold standard markers based on the criteria of efficacy, specificity, and reliability; however, studies are still in progress. In the future, the use of miRNAs is promising as well as the combination of multiple markers. In this way, it will be possible to increase the sensitivity and specificity to validate systems or models for determining wound vitality in forensic practice.

Assessing wound vitality in decomposed bodies: a review of the literature

The capability of discriminating between a vital and a post-mortem injury has always been a central theme in forensic pathology, particularly when the corpse is an advanced state of decomposition. Post-mortem decay of the body can mask or disrupt the classical features of a skin lesion, making it difficult to establish the cause and manner of death. Taphonomically challenging situations pose several interpretative issues of skin lesions which need to be addressed with scientifically recent methods that are still limited in the forensic literature. For that reason, the present research aims at resuming what is currently available in the attempt to provide some insight regarding this topic. This review considers only original researches, in which the markers of vitality were studied a significant amount of time after death, in order to test post-mortem persistency of these markers over time. A number of 132 original articles and reviews were considered, and the most significant results are resumed in an overview table and in two intuitive figures. Though many researchers tried to establish the vitality of lesions in specimen, few analysed samples from bodies when a significant degree of putrefaction or burning had occurred. The most significant marker proved to be GPA, which sowed a satisfying persistence over time (up to 6 months in air putrefaction and 15 days in water). However, what clearly emerged is that further studies are needed to address the challenges of taphonomically transformed specimen and to possibly neutralize the variability of experimental conditions, which affect the reproducibility of results. In conclusion, this study could be a starting point for providing food for thoughts about the most useful markers to search for in unusually tricky autopsy cases.

mRNA microarray analysis for the identification of potential biomarkers for vital reaction in burned skin: a preliminary pilot study

The identification of ante- and post-mortem burns is challenging in forensic pathology. In this study, microarray analysis was used to detect the mRNA expression profiles in the skin of an experimental burn mouse model; the results were validated using RT-qPCR. Differentially expressed mRNAs (DE-mRNAs) were assessed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Our results revealed that mRNA expression of 501 genes was significantly different, of which 273 were upregulated and 228 were downregulated in ante-mortem burned mice skin. The expression levels of eight random mRNAs were consistent when measured using the microarray assay-based method and RT-qPCR. Genes from different functional categories and signalling pathways were enriched, including interleukin-20 binding, type IV hypersensitivity, negative regulation of acute inflammatory response, sensory organ development, endocytosis, neuroactive ligand-receptor interaction, and Jak-STAT signalling pathway. Only five of the eight mRNAs exhibited consistent changes in expression between burned skin samples of mice and human autopsy specimens. Our findings showed that DE-mRNAs revealed using microarray are potential biomarkers of ante-mortem burns. However, DE-mRNAs identified from experimental animal models cannot be directly extended to autopsy specimens without careful validation.

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.

Forensic Impact of the Omics Science Involved in the Wound: A Systematic Review

Background: In forensic autopsies, examining the wounds is one of the most critical aspects to clarify the causal relationship between the cause of death and the wounds observed on the corpse. However, on many occasions, it is difficult to differentiate antemortem injuries from post-mortem injuries, mainly when they occur very close to the moment of death. At present, various studies try to find biomarkers and clarify the molecular mechanisms involved in a wound due to the high variability of conditions in which they occur, thus being one of the most challenging problems in forensic pathology. This review aimed to study the omics data to determine the main lines of investigation emerging in the diagnosis of vital injuries, time of appearance, estimation of the age and vitality of the wound, and its possible contributions to the forensic field.

Methods: A systematic review of the human wound concerning forensic science was carried out by following PRISMA guidelines.

Results: This study sheds light on the role of omics research during the process of wounding, identifying different cytokines and other inflammatory mediators, as well as cells involved in the specific stage of the wound healing process, show great use in estimating the age of a wound. On the other hand, the expression levels of skin enzymes, proteins, metal ions, and other biomarkers play an essential role in differentiating vital and post-mortem wounds. More recent studies have begun to analyze and quantify mRNA from different genes that encode proteins that participate in the inflammation phase of a wound and miRNAs related to various cellular processes.

Conclusions: This study sheds light on the role of research in the molecular characterization of vital wounds, heralding a promising future for molecular characterization of wounds in the field of forensic pathology, opening up an important new area of research.

Systematic Review Registration: URL: https://www.crd.york.ac.uk/prospero/#myprospero, Identifier: CRD42021286623.

MiRNAs as New Tools in Lesion Vitality Evaluation: A Systematic Review and Their Forensic Applications

Wound vitality demonstration is one of the most challenging fields in forensic pathology. In recent years, researchers focused on the application of histological and immunohistochemical staining in this sphere of study. It is based on the detection of inflammation, red cell infiltration, and tissue alterations at the histological examination, all of which are supposedly present in antemortem rather than post-mortem wounds. Nevertheless, some doubts about the reliability of those markers have arisen. Furthermore, the lack of a standardized protocol and the operator dependency of this approach make the proper interpretation of its results difficult. Moreover, a differential miRNAs expression has been demonstrated in antemortem and post-mortem wounds. Herein, a systematic review concerning the current knowledge about the use of miRNAs in lesion vitality evaluation is carried out, to encourage researchers to deepen this peculiar study area. A compendium about the potential miRNAs that may be further investigated as vitality markers is also provided. The aim is to collect all available data about this topic to direct further studies on this field and highlight the future applications of miRNAs in forensic pathology. We found 20 articles and a total of 51 miRNAs that are involved in inflammation and wound healing. Further studies are certainly needed to deepen the role of miRNAs in inflammatory processes in lesioned skin and to evaluate their reliability in distinguishing between antemortem and post-mortem lesions.

Potential usefulness of otoscopy in the evaluation of hanging deaths: A report of two cases

The significance of examination of the tympanic membrane (TM) has been previously reported in cases of strangulation, traumatic asphyxia, and drowning. We report otoscopic findings in two victims of suicidal hanging, including hemotympanum, bleeding from superficial vessels of the TM, perforation of the TM, and gross bulging of the pars-tensa with a bluish hue. These two cases also show petechial hemorrhages in the TM, which is a previously reported finding in cases of hanging. Postmortem otoscopic examination of victims of hanging may provide information useful in the determination of vitality of hanging.

The forensic application of the Glycophorin A on the Amussat's sign with a brief review of the literature

Even if the Amussat's sign is known since the mid-19th century, few studies have been made in order to assess its real occurrence. In particular, the histopathologic examination of the Amussat's sign lacks in the medicolegal literature. The review of the literature shows indeed a significant range of variability (from 1.1 % up to 25 %) regarding the macroscopic detection of the Amussat's sign. In this study, the authors report that the identification of a vital Amussat's sign is important and may require the immunohistochemical staining for the Glycophorin A (a marker of vital reaction). The victim was a 63-year-old man, who was found suspended from the staircase with a rope. Both the carotid arteries were opened in situ by using fine scissors with blunt tips. A horizontal lesion (length 4 mm) of the intima of the left common carotid artery was documented. A sample was obtained; then, a standard post-fixative histopathologic examination and immunohistochemical staining for the Glycophorin A were carried out. The standard histopathologic examination only revealed the intimal laceration with a poor hemorrhagic infiltration. However, the immunohistochemical staining for the Glycophorin A allowed the clear identification of the hemorrhagic infiltration, which was documented both in the intimal laceration and in the periadventitial soft tissues. The immunohistochemical staining for the Glycophorin A can identify the vitality of an Amussat's sign. When an Amussat's sign is documented, the Glycophorin A may therefore help the forensic pathologist to differentiate a hanging death from a postmortem suspension of the body.

Investigating the phenomenon of overkill in Greece: A forensic psychiatric autopsy study between 2005 and 2020

The purpose of this study was to investigate overkill in the Greek population from a criminological and victimological point of view and explore possible correlations of the phenomenon with socio-cultural or psychiatric factors. Overall, 158 autopsies of overkill victims were identified throughout the 15-year records of the national forensic laboratories throughout the northern Greek mainland. The pattern that has emerged from the statistical results of the present study on the victims of overkill within the Greek borders was generally in line with global statistics on homicide victims, but also presented differences. The phenomenon correlated more with homicides in the context of mental disorders (within schizophrenia spectrum), other crimes (such as burglary) as well as domestic violence. Overall, males outnumbered females both as victims (approximately threefold) and as perpetrators in overkill homicide cases, but regarding domestic violence, the sad majority of overkill victims stood for females murdered with excessive violence by male relatives. Close female relatives (especially mothers and grandmothers) were also victimized by psychiatrically ill offenders. Female perpetrators tended to attack male individuals with whom they shared a relationship (intimate partners). An important finding was the fact that less than half the offenders' population with major mental disorders were diagnosed at the time of the offense. Overkill victims were found, on average, to be older than average homicide victims, being probably associated with the entailed difference in the physical strength ratio between the victim and the perpetrator.

Unusual (self-)injuries in a case of hanging

A 41-year-old man was found by his wife in an atypical hanging situation in their apartment. As there was a known previous psychiatric illness and a history of suicide attempts, the investigative authorities assumed this case was a suicide. However, the autopsy revealed numerous findings that are unusual for a suicidal atypical hanging, including numerous cuts on the face, the arms and the penis. According to his wife, the deceased suffered from Asperger's syndrome with auto-aggressive behavior. He had allegedly injured himself with household scissors in the days before his death and had hit himself numerous times in the face the night before his death. His wife also revealed that she would injure him with scissors at his request. Even though the observed injury pattern in this case contradicted a self-infliction, the information given by the wife about the chronology of the occurrence of injuries could be reconciled with the findings of the immunohistochemical estimation of wound age. The circumstances that led to the hanging remained unresolved.

Death in the sauna-vitality markers for heat exposure

In sauna-associated deaths, the vitality of heat exposure is of great importance. Two case reports address this. First, we present the case of a 77-year-old man who was found dead in the sauna of his family home. When found, the sauna door was closed, and the sauna indicated a temperature of 78 °C. The body had already begun to decay and was partially mummified when it was found. In the other case, a 73-year-old woman was found dead in the sauna by her husband. In this case, the sauna door was also closed. The sauna was still in operation at a temperature of approximately 70 °C. Epidermal detachments were found. In both autopsies and their follow-up examinations, there were no indications of a cause of death competing with heat shock. The expression of heat shock proteins in kidneys and lungs and the expression of aquaporin 3 in skin were investigated to detect pre-mortal temperature influences.

MicroRNAs: An Update of Applications in Forensic Science

MicroRNAs (miRNAs) are a class of non-coding RNAs containing 18–24 nucleotides that are involved in the regulation of many biochemical mechanisms in the human body. The level of miRNAs in body fluids and tissues increases because of altered pathophysiological mechanisms, thus they are employed as biomarkers for various diseases and conditions. In recent years, miRNAs obtained a great interest in many fields of forensic medicine given their stability and specificity. Several specific miRNAs have been studied in body fluid identification, in wound vitality in time of death determination, in drowning, in the anti-doping field, and other forensic fields. However, the major problems are (1) lack of universal protocols for diagnostic expression testing and (2) low reproducibility of independent studies. This review is an update on the application of these molecular markers in forensic biology.