Les marqueurs de vitalité des blessures en pathologie médicolégale

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.

Dating Skin Lesions of Forensic Interest by Immunohistochemistry and Immunofluorescence Techniques: A Scoping Literature Review

Wound age estimation is a significant issue in forensic pathology. Although various methods have been evaluated, no gold standard system or model has been proposed, and accurate injury time estimation is still challenging. The distinction between vital skin wounds-i.e., ante-mortem lesions-and skin alterations that occur after death is a crucial goal in forensic pathology. Once the vitality of the wound has been confirmed, the assessment of the post-trauma interval (PTI) is also fundamental in establishing the causal relationship between the traumatic event and death. The most frequently used techniques in research studies are biochemistry, molecular biology, and immunohistochemistry (IHC). Biochemical methods take advantage of the chemical and physical techniques. A systematic literature search of studies started on 18 February 2023. The search was conducted in the main databases for biomedical literature, i.e., PubMed and Scopus, for papers published between 1973 and 2022, focusing on different techniques of immunohistochemistry and immunofluorescence (IF) for estimating the PTI of skin wounds. The present study involves a comprehensive and structured analysis of the existing literature to provide a detailed and comprehensive overview of the different IHC techniques used to date skin lesions, synthesize the available evidence, critically evaluate the methodologies, and eventually draw meaningful conclusions about the reliability and effectiveness of the different markers that have been discovered and used in wound age estimation.

[TGFβ1 antibodies application for IHC determination of injuries vitality. The experimental results]

THE AIM OF THE STUDY

Is to examine the applicability of IHC staining method with TGFβ1 antibodies for injuries vitality determination. 72 skin autopsy samples with mechanical injuries from 12 persons were divided to 3 groups (n=24 in each group): vital injuries, postmortal injuries, control non-injured samples. A routine histological examination using standard H&E stain and IHC with TGFβ1 antibodies was performed. We concluded the positive TGFβ1 staining was in keratinocytes in vitally injured skin and the negative one in postmortally injured and control non-injured samples. The role of TGFβ1 in the injuries healing process and the further examinations of the TGFβ1 staining method application for determination of injuries vitality are discussed.

Antigenicity Preservation Is Related to Tissue Characteristics and the Post-Mortem Interval: Immunohistochemical Study and Literature Review

The main aim of this study was to investigate the post-mortem proteolytic degradation process of selected tissue antigens and correlate it to the post-mortem interval. During the autopsy of 12 cadavers (time interval ranging 1 day–2 years after death) samples of skin, liver, kidney, and spleen were collected. All samples were formalin-fixed and paraffin-embedded. Four µm paraffin sections were used for hematoxylin–eosin staining and immunohistochemical analysis (Ki67, Vimentin, Pan cytokeratin, and CD20). Data reported here show that immunohistochemical reactivity preservation was related to the characteristics of the tissues. In particular, the most resistant tissue was the skin, where the autolysis phenomena were not appreciable before 5 days. On the contrary, the liver and the spleen underwent early autolysis, while the kidney displayed an early autolysis of the tubules and a late one of the glomeruli. As concerns specific antigens, immunoreactivity was lost earliest for nuclear antigens as compared to cytoplasmic ones. In conclusion, our results demonstrate that immunohistochemical detection of specific antigens may be useful in estimating the post-mortem interval, especially when we need to know whether the post-mortem interval is a few days or more than 7–10 days.

[Current views on methods of determining the age of injuries in the practice of the forensic expert]

The review objective is to summarize the current data on new methods development for detection and determination of the age of injuries (AI) and to analyze the prospects of their use in the practice of forensic medical experts. The injury healing processes in various human body tissues are described in detail, and data on biomarkers of healing and their role are provided. Three main diagnostic methods for AI were analyzed: immunohistochemical, molecular biological study, and biophysical objectivization. Their advantages and disadvantages, as well as ways of further improvement of these methods, are considered.

The Role of miRNAs as New Molecular Biomarkers for Dating the Age of Wound Production: A Systematic Review

BACKGROUND

The timing of wounds production is a significant issue in forensic pathology. Although various methods have been evaluated, obtaining an accurate dating of lesions is still a challenge. The pathologist uses many parameters to value wound age, such as histological and immunohistochemical. In recent years, there have been many studies regarding the use of miRNAs in wound-age estimation; indeed, miRNAs have multiple potential uses in forensic pathology.

SCOPE

This review aims to verify the efficacy and feasibility of miRNAs as a tool for determining the timing of lesions.

MATERIALS AND METHODS

The authors conducted the systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed was used as a search engine to find articles published between January, 1st 2016 and October, 1st 2021, to evaluate the current state of the art regarding wound-age estimation.

RESULTS

A total of 256 articles were collected; after screening according to PRISMA guidelines, the systematic review included 8 articles. The studies included in this review were all Original articles evaluating the use of biomarkers for wound-age determination.

DISCUSSION AND CONCLUSION

The literature review showed that analysis of miRNA is an innovative field of study with significant potentiality in forensic pathology. There are few studies, and almost all of them are at an early stage. The challenge is to understand how to standardize the samples' selection to obtain reliable experimental data. This observation represents a necessary prerequisite to planning further clinical trials.

[Reliability of the immunohistochemical estimation of vitality and injury age: analysis and perspectives for study]

This review summarizes the literature data on the applicability of various immunohistochemical markers for the diagnosis of vitality and injury age. Current state of the problem of the reliability of the estimation of injury vitality, and the most promising immunohistochemical markers for further study are also considered.

Pathology diagnosis of an atypical thyroid cartilage lesion

In forensic practice, laryngeal lesions are of particular interest for the pathologist, as they may sign foul play. We report the case of a decedent, whose body was found in an advanced state of putrefaction, at the bottom of a ledge, after a one-month disappearance. The face and neck were skeletised. The autopsy found multiple traumatic injuries. The hyoid bone was separated from the other laryngeal structures and seemed to be macroscopically normal. However, the thyroid cartilage had a thin notch at the base of the right upper horn. The nature of this notch was determined by microscopic examination: analysis showed incompletely ossified fibrous tissue, bordered by a line of enchondral ossification. We concluded that the notch was an old fracture, not concomitant with the polytrauma secondary to the fall that was the cause of death. This case shows that microscopic examination may allow the distinction between recent and old wound. Such a distinction is especially important in this context of polytrauma, where lesions could have been secondary to a fall, caused by a third party or unconnected with events.

Tissue Microarray Analysis Applied to Bone Diagenesis

Taphonomic processes affecting bone post mortem are important in forensic, archaeological and palaeontological investigations. In this study, the application of tissue microarray (TMA) analysis to a sample of femoral bone specimens from 20 exhumed individuals of known period of burial and age at death is described. TMA allows multiplexing of subsamples, permitting standardized comparative analysis of adjacent sections in 3-D and of representative cross-sections of a large number of specimens. Standard hematoxylin and eosin, periodic acid-Schiff and silver methenamine, and picrosirius red staining, and CD31 and CD34 immunohistochemistry were applied to TMA sections. Osteocyte and osteocyte lacuna counts, percent bone matrix loss, and fungal spheroid element counts could be measured and collagen fibre bundles observed in all specimens. Decalcification with 7% nitric acid proceeded more rapidly than with 0.5 M EDTA and may offer better preservation of histological and cellular structure. No endothelial cells could be detected using CD31 and CD34 immunohistochemistry. Correlation between osteocytes per lacuna and age at death may reflect reported age-related responses to microdamage. Methodological limitations and caveats, and results of the TMA analysis of post mortem diagenesis in bone are discussed, and implications for DNA survival and recovery considered.

A data model for clinical legal medicine practice and the development of a dedicated software for both practitioners and researchers

OBJECTIVE

To present a data model for clinical legal medicine and the software based on that data model for both practitioners and researchers. The main functionalities of the presented software are computer-assisted production of medical certificates and data capture, storage and retrieval.

METHODS

The data model and the software were jointly developed by the department of forensic medicine of the Jean Verdier Hospital (Bondy, France) and an bioinformatics laboratory (LIMICS, Paris universities 6-13) between November 2015 and May 2016. The data model was built based on four sources: i) a template used in our department for producing standardised medical certificates; ii) a random sample of medical certificates produced by the forensic department; iii) anterior consensus between four healthcare professionals (two forensic practitioners, a psychologist and a forensic psychiatrist) and iv) anatomical dictionaries. The trial version of the open source software was first designed for examination of physical assault survivors.

RESULTS

An UML-like data model dedicated to clinical legal practice was built. The data model describes the terminology for examinations of sexual assault survivors, physical assault survivors, individuals kept in police custody and undocumented migrants for age estimation. A trial version of a software relying on the data model was developed and tested by three physicians.

DISCUSSION

The software allows files archiving, standardised data collection, extraction and assistance for certificate generation. It can be used for research purpose, by data exchange and analysis. Despite some current limitations of use, it is a tool which can be shared and used by other departments of forensic medicine and other specialties, improving data management and exploitation. Full integration with external sources, analytics software and use of a semantic interoperability framework are planned for the next months.