FVIIIra, CD15, and tryptase performance in the diagnosis of skin stab wound vitality in forensic pathology

Expression of matrix metalloproteinase-9 (MMP-9) in human skin within 1 hour after injury through immunohistochemical staining: a pilot study

Matrix metalloproteinase-9 (MMP-9) is involved in tissue remodeling and in skin wound healing. The present study focuses on the MMP-9 expression in epidermal wound healing within 1 h after injury, to test whether MMP-9 can be used to estimate the time of injury in forensic practice.A sample consisting of 5 individuals undergoing surgery was analyzed. With the consent of the patients, sections of skin were removed from the surgical wound at predefined time intervals. For each subject, 8 sections were taken, one for each time interval defined at 0 '- 1' - 3 '- 5' - 10 '- 15' - 30 '- 60' minutes. The specimens were immunostained with MMP-9, and the number of positively stained cells was examined.The number of positively stained cells showed an increasing trend as a function of time. Less than 30 positively stained cells were found in all cases within 3 min. At the post-infliction time of 5 min, the number of positively stained cells exceeded 30 in 3 out of 5 cases. The number of MMP-positive cells exceeded 40 in all cases in over 10 min.In the light of these results, the count of MMP-9 positive cells might be a useful marker in the wound-age estimation within 1 h in forensic setting. More research is required to collect more samples and to compare samples from the hyperacute phase with those from several days after injury.

Immunohistochemical analysis of PDGFR-α for wound age determination

Immunohistochemical analysis of platelet-derived growth factor receptor-α (PDGFR-α) was performed on human skin wounds obtained from forensic autopsy cases. Thirty human skin wounds were collected at different post-infliction intervals as follows: Group I, 4 h to 3 days (n = 16); Group II, 4 to 7 days (n = 7); Group III, 9 to 10 days (n = 3); and Group IV, 14 to 20 days (n = 4). Immunopositive reactions for PDGFR-α were not observed in the uninjured human skin specimens. In a semi-quantitative morphometrical analysis, the number of PDGFR-α-positive cells was observed increased in Group II, with the average number of PDGFR-α-positive cells being the highest in Group II. Additionally, in Group II, all specimens showed PDGFR-α-positive cells, with an average number of > 200 cells in five fields of view, suggesting a wound age of 4 to 7 days. Taken together, the immunohistochemical detection of PDGFR-α in human skin wounds can be a useful tool for wound age determination.

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.

[Detection of some markers of the early phase of the inflammatory and reparative process in mechanical skin injuries]

OBJECTIVE

To examine the applicability of IHC staining method: with TGF-β1 antibodies (serial examination, statistically processed results) and with mast cell tryptase antibodies for injuries vitality determination.

MATERIAL AND METHODS

261 skin autopsy samples with mechanical injuries from 29 persons were divided to 3 groups (87 in each group): vital injuries, postmortal injuries, control non-injured samples. A routine histological examination using standard H&E stain and IHC both with TGF-β1 and mast cells tryptase antibodies was performed.

RESULTS AND CONCLUSION

The positive TGF-β1 staining (score 2-3) was found in keratinocytes in vitally injured skin and the negative or weak one (score 0-1) was found in control postmortally injured and non-injured samples. Additionally, dermal TGF-β1 expression was found in some vitally injured skin samples. The difference between vitally injured skin and control samples was statistically significant (p<0.05). No significant difference of dermal mast cells density in groups 1, 2, 3 was found.

Novel ratio-expressions of genes enables estimation of wound age in contused skeletal muscle

Given that combination with multiple biomarkers may well raise the predictive value of wound age, it appears critically essential to identify new features under the limited cost. For this purpose, the present study explored whether the gene expression ratios provide unique time information as an additional indicator for wound age estimation not requiring the detection of new biomarkers and allowing full use of the available data. The expression levels of four wound-healing genes (Arid5a, Ier3, Stom, and Lcp1) were detected by real-time polymerase chain reaction, and a total of six expression ratios were calculated among these four genes. The results showed that the expression levels of four genes and six ratios of expression changed time-dependent during wound repair. The six expression ratios provided additional temporal information, distinct from the four genes analyzed separately by principal component analysis. The overall performance metrics for cross-validation and external validation of four typical prediction models were improved when six ratios of expression were added as additional input variables. Overall, expression ratios among genes provide temporal information and have excellent potential as predictive markers for wound age estimation. Combining the expression levels of genes with ratio-expression of genes may allow for more accurate estimates of the time of injury.

Immunohistochemical detection of Fibronectin, P-Selectin, FVIII, HSP-70 and MRP-8 in the skin of ligature marks of suicidal hangings

The determination of vitality of skin injuries is one of the most central research areas in forensic pathology for it is often necessary to discern antemortem from postmortem damage. Typical is the case of a hanging, which should be distinguished from the postmortem suspension of a body. In this study, 15 human skin samples from ligature marks (study group) of victims of suicidal hanging and 15 uninjured skin samples (negative control group) were analyzed. In addition, 15 skin samples from ecchymoses in homicide victims with short survival intervals were investigated as a positive control group. Sections were processed for immunohistochemistry in order to detect the expression of Fibronectin, P-Selectin, FVIII, HSP-70, and MRP8. Immunohistochemical reactions were classified semiquantitatively (mild - score 1, moderate - score 2, and intense - score 3). In the ligature marks, Fibronectin was significantly less expressed compared to ecchymoses. The expression was similar to hanging marks and uninjured skin. In both ligature marks and ecchymoses, the expression of P-Selectin was significantly increased compared to uninjured skin. In both ligature marks and ecchymoses, expression of HSP-70 was significantly decreased in the epidermis compared to uninjured skin. In both ligature marks and ecchymoses, the expression of FVIII and MRP8 was significantly increased in the dermis and hypodermis compared to uninjured skin. The results of this study show that the immunohistochemical study of early inflammatory and coagulation factors could help determine the vitality of ligature marks. The combined analysis of P-Selectin, FVIII, HSP-70, and MRP-8 can be considered for this purpose.

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.

Microbial community analyses provide a differential diagnosis for the antemortem and postmortem injury of decayed cadaver: An animal model

Differentiating antemortem injury from postmortem injury of decayed cadavers is one of the difficult issues in forensic science. Forensic pathologists identify antemortem injury according to the macroscopic and microscopic vital reactions taken place after being injured. However, the decomposition would render those vital reactions ineffective. Microbiomes have been widely used in forensic science due to their succession with time and sensitivity to vary of environment. In this study, microbiomes were introduced to determine whether the bacterial communities can be used to distinguish between the ante- and postmortem injuries through an animal experiment. Our findings showed that the differences of bacterial community were increasingly apparent from the 6th to 9th day after the wound created when the types of wounds were unidentified by morphological examination due to decomposition. The biomarkers at the genus level could effectively distinguish between injury types, Among them, Enterococcus and Enterobacter were only observed in the antemortem injured group, while Staphylococcus and Acinetobacter were only in the postmortem injured group. It is possible to tell whether cadaveric injuries developed before or after death by detecting differences in the bacterial communities of putrefying wounds. This study provides a new perspective for the differences between ante- and postmortem injuries and provides a promising method for us to identify the ante- and postmortem wounds, especially in decomposed cadavers.

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.

Myeloperoxydase and CD15 With Glycophorin C Double Staining in the Evaluation of Skin Wound Vitality in Forensic Practice

Background

The determination of skin wound vitality based on tissue sections is a challenge for the forensic pathologist. Histology is still the gold standard, despite its low sensitivity. Immunohistochemistry could allow to obtain a higher sensitivity. Upon the candidate markers, CD15 and myeloperoxidase (MPO) may allow to early detect polymorphonuclear neutrophils (PMN). The aim of this study was to evaluate the sensitivity and the specificity of CD15 and MPO, with glycophorin C co-staining, compared to standard histology, in a series of medicolegal autopsies, and in a human model of recent wounds.

Methods

Twenty-four deceased individuals with at least one recent open skin wound were included. For each corpse, a post-mortem wound was performed in an uninjured skin area. At autopsy, a skin sample from the margins of each wound and skin controls were collected (n = 72). Additionally, the cutaneous surgical margins of abdominoplasty specimens were sampled as a model of early intravital stab wound injury (scalpel blade), associated with post-devascularization wounds (n = 39). MPO/glycophorin C and CD15/glycophorin C immunohistochemical double staining was performed. The number of MPO and CD15 positive cells per 10 high power fields (HPF) was evaluated, excluding glycophorin C—positive areas.

Results

With a threshold of at least 4 PMN/10 high power fields, the sensitivity and specificity of the PMN count for the diagnostic of vitality were 16 and 100%, respectively. With MPO/glycophorin C as well as CD15/glycophorin C IHC, the number of positive cells was significantly higher in vital than in non-vital wounds (p < 0.001). With a threshold of at least 4 positive cells/10 HPF, the sensitivity and specificity of CD15 immunohistochemistry were 53 and 100%, respectively; with the same threshold, MPO sensitivity and specificity were 28 and 95%.

Conclusion

We showed that combined MPO or CD15/glycophorin C double staining is an interesting and original method to detect early vital reaction. CD15 allowed to obtain a higher, albeit still limited, sensitivity, with a high specificity. Confirmation studies in independent and larger cohorts are still needed to confirm its accuracy in forensic pathology.

[Two experimental models for wound vitality evaluation in forensic pathology: A clinical prospective non-interventional study and an animal model]

AIM OF THE STUDY

In forensic pathology, wound age evaluation allows to determine if a wound was inflicted before or after death, and to date wounds of different ages. This dating is performed in conventional histopathology by observing inflammatory cells and hemorrhage at the wound site. However, these criteria seem to show low sensitivity and/or specificity. The aim of our study was to compare two models of wound vitality evaluation: a human surgical model, and a porcine experimental model; using these histological criteria.

PATIENTS AND METHOD

In the two human (n=38) and porcine (n=11) models, three wounds were performed at regular time-lapse before devascularization/sacrifice, and a control wound after devascularization/sacrifice. The main evaluation criteria were the presence of interstitial hemorrhage and the number of interstitial polymorphonuclear neutrophils at 10 high power fields.

RESULTS

In the two models, the number of polymorphonuclears neutrophils was significantly higher in vital wounds compared to the post-devascularization/sacrifice wounds (P<0.001), with a very low sensitivity (human model: 4.3%; porcine: 47%). Hemorrhagic infiltration was more frequent in vital wounds (human: P<0.001; porcine: P=0.01), with a low specificity (human: 48%; porcine: 54%).

DISCUSSION AND CONCLUSION

This first study confirms, in the two models, the limitations of conventional histopathology in wound vitality evaluation. The next step will be testing several immunohistochemical markers in the two models.

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.

Wound Vitality in Decomposed Bodies: New Frontiers Through Immunohistochemistry

Background: The question about wound vitality and the estimation of wound age of production are two of the classic investigation fields of forensic sciences. To answer this, the techniques most frequently used in research studies are immunohistochemistry (IHC), molecular biology, and biochemistry. Despite the great data on the literature about the usefulness of IHC in forensic pathology, there is always a request for further studies, especially on tissues altered by putrefactive phenomena. In fact, the degradation of the tissues is intended as the main limiting factor to the use of this technique.

Scope: The aim of this pilot study was to evaluate the immunohistochemical behavior of samples collected from decomposed bodies (in different putrefaction phases) and to relate these findings to wound vitality and postmortem interval.

Materials and Methods: Samples of skin and soft tissues were collected during autopsies, which were executed on decomposed bodies, whose cause of death was concluded to be traumatic. An immunohistochemical study was performed using antibodies against CD15, CD45, IL-15, tryptase, and glycophorin-A MMPs (endopeptidases involved in degrading extracellular matrix proteins: MMP-9 and MMP-2). An immunohistochemistry (IHC) reaction was evaluated according to a qualitative method as the following legend: (0): not expressed, (+): isolated and disseminated expression, (++): expression in groups or widespread foci, and (+++): widespread expression.

Results: Most of the tested markers (tryptase, glycophorin, IL15, CD 15, CD 45, and MMP9) showed to be highly expressed in the tissue of putrefied skin for 15 days.

Discussion and Conclusion: Although certainly inconclusive, this experimental application demonstrated that a nonexclusive but combined use of multiple antibodies is appropriate to verify wound vitality in decomposed bodies. Among them, GPA exhibited major reliability.

Immunohistochemical analysis of von Willebrand factor expression in myocardial tissues from autopsies of patients with ischemic heart disease

von Willebrand factor (VWF) plays a crucial role in hemostasis and thrombosis. VWF is involved in platelet attachment to the subendothelium, serving as a carrier protein for coagulation factor VIII. In this study, myocardial tissues from deceased patients with ischemic heart disease and a mouse model of acute myocardial infarction were subjected to immunohistochemistry to determine VWF expression. We examined 28 neutral formalin-fixed, paraffin-embedded myocardial tissue samples obtained from the autopsies of patients who were diagnosed with ischemic heart disease within 48 h postmortem. Most myocardial cells were negative for VWF, although some cells showed nonspecific positivity. Elevated VWF expression was observed around myocardial cells undergoing remodeling, suggesting that endothelial proliferation occurred at these sites. In contrast, completely fibrotic myocardial foci did not show upregulated VWF expression. Positivity in fibrin deposition and hemorrhagic sites was observed. The same VWF expression characteristics as those observed in the human samples were observed in the mouse model. VWF immunostaining as an endothelial marker may be a useful supplementation to conventional staining techniques that are currently used in the diagnosis of ischemic heart disease in terms of examining the timing of myocardial remodeling in detail and highlighting the remodeling process.

Application of CD83 and HSF5 to Identify Antemortem and Postmortem Skin Burns

OBJECTIVES

To explore the forensic application value of cluster of differentiation 83 (CD83) and heat shock transcription factor 5(HSF5) in identifying antemortem and postmortem skin burns.

METHODS

Through reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR), CD83 and HSF5 mRNA levels in the skin tissues of antemortem and postmortem burned mice and human samples were detected quantitatively.

RESULTS

Compared with the control group and the postmortem burned group, the mRNA levels of CD83 and HSF5 in antemortem burned mice were higher. The high mRNA expressions of CD83 could be detected 96 h after death, and the mRNA expressions of HSF5 could be observed 72 h after death. Compared with undamaged skin, increased CD83 and HSF5 mRNA levels were detected in 11 out of 15 cases(P<0.05).

CONCLUSIONS

CD83 and HSF5 can be used in forensic practice as indicators for vital reaction in antemortem burn identification.

Cytokines as new biomarkers of skin wound vitality

BACKGROUND

The diagnosis of skin wound vitality is currently based on standard histology, but histological findings lack sensitivity in case of a short survival time. New reliable biomarkers of vitality are therefore strongly needed. We assessed the ability of 10 candidate cytokines (IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α) to discriminate between vital and early post-mortem wounds.

METHODS

Twenty-four cadavers with a recent open skin wound (< 3 h) were included (20 men, 4 women, mean age = 51.0 ± 24.3 years). An early post-mortem wound was performed in an uninjured skin area, and both wounds were sampled at the autopsy (post-mortem interval (PMI) = 66.3 ± 28.3 h). Needle-puncture sites related to resuscitation cares were included as very early post-mortem wounds (n = 6). In addition to standard histology, cytokines levels were simultaneously measured in each sample using a multiplex sandwich immunoassay, then normalized on healthy skin levels. A quantitative evaluation of IL-8-positive cells in ante- and post-mortem wound samples was also performed.

RESULTS

In the training set of samples (n = 72), cytokine levels were significantly higher in vital wounds (mean age = 47 ± 53 min) than in post-mortem wounds (mean PMI = 6.9 ± 9.0 h) (p < 0.2), except for two cytokines (IFN-γ and IL-2). IL-8 was the best discriminatory cytokine (Se = 54%, Sp = 100%, AUC = 0.79), while a multivariate model combining IL-4 and IL12p70 was a bit more discriminant (Se = 55%, Sp = 100%, AUC = 0.84). In the validation set (n = 72), the discriminatory power of the cytokines and the predictive model was slightly lower, with IL-8 remaining the best cytokine (Se = 46%, Sp = 96%, AUC = 0.75). The predictive model remained highly specific (Sp = 100%). Both the cytokines and the predictive model allowed the iatrogenic injuries to be correctly classified as post-mortem wounds. Standard histology and immunohistochemistry showed 21% sensitivity and a specificity of 79% and 100%, respectively. Only two iatrogenic wounds could be properly categorized histologically.

CONCLUSION

This study suggests that cytokines could be useful biomarkers of skin wound vitality and that the immunoassay method could be more sensitive than immunohistochemistry to identify wounds with a short survival time. Further research is underway to confirm these preliminary data.

[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.

Forensic pathological study on temporal appearance of dendritic cells in skin wounds

Dendritic cells (DCs) can essentially contribute to innate and adaptive immune system in various organs. A double-color immunofluorescence analysis was carried out with anti-CD11c and -HLA-DRα antibodies to detect DCs in 53 skin wounds (their postinfliction intervals: group I, 0-3 days; group II, 4-7 days; group III, 9-14 days; and group IV, 17-21 days). CD11c⁺HLA-DRα⁺ DCs were first observed in skin wounds with postinfliction intervals of 3 days, and the DC numbers were found to be elevated in skin wounds with the subsequent increase in postinfliction intervals. Semi-quantitative morphometric analyses showed that the DC number was the highest in the 12-day-old wound. More than 50 DCs were present in 8 of 10 samples (80%) in group II and 14 of 16 samples (87.5%) in group III, and there was no difference between the two groups. Thus, the presence of DCs in a skin wound was possibly estimated as postinfliction intervals of at least 3 days. Furthermore, when a skin wound contained > 50 DCs, its age would be judged as 4-14 days. Collectively, the appearance of DCs in human skin wounds may provide useful information in determining the age of a wound.

ATF3 mRNA, but not BTG2, as a possible marker for vital reaction of skin contusion

The detection of vitality of wounds, especially when the wounds are inflicted very close to the time of death, is one of the most challenging issues in forensic pathology. This study investigated expression levels of ATF3 and BTG2 in mouse and human skin wounds. Protein levels examined by western blot showed that there was no significant change in ATF3 and BTG2 between wounded and intact skins. However, mRNA levels demonstrated higher expression of ATF3 and BTG2 in ante-mortem contused mouse skins, compared with the intact and postmortem contused skins. Increased ATF3 and BTG2 in the level of mRNA could also be detected until 96h and 48h after death, respectively. Human wounded skin samples from forensic autopsy cases were also examined. Increased ATF3 mRNA levels were detected until 48h after autopsy in 5 of 6 cases. However, no differences were observed between wounded and intact skins for BTG2. These findings suggest that the detection of mRNA levels of ATF3, but not BTG2, can be considered as a potential marker for vital reaction of skin contusion. Postmortem human samples should be used in order to validate the availability of markers screened by animal experiment.

IL-6 and IL-20 as potential markers for vitality of skin contusion

The detection of vitality of wounds is very important in forensic practice. This study is performed using quantitative real-time reverse transcriptase polymerase chain reaction (RT-qPCR) in both mouse and human skin wounds for the application of IL-6 and IL-20 in order to differentiate intravital wounds from postmortem wounds. RT-qPCR analysis of contused mouse skin showed that increased IL-6 and IL-20 mRNA levels were found in comparison to intact skin tissues. The increased mRNA expressions of IL-6 and IL-20 were observed until 72 h after death in contused mouse skin, whereas there were no marked changes in these two cytokines in the postmortem contusion group. The alterations of IL-6 and IL-20 can also be detected in human skin wound samples. These finding suggest that mRNA levels of IL-6 and IL-20 might be used as potential markers for vital reaction.

CXCL1 and CXCR2 as potential markers for vital reactions in skin contusions

Detection of the vitality of wounds is one of the most important issues in forensic practice. This study investigated mRNA and protein levels of CXCL1 and CXCR2 in skin wounds in mice and humans. Western blot analysis of CXCL1 and CXCR2 protein levels showed no difference between wounded and intact skin. However, mRNA levels demonstrated higher expression of CXCL1 and CXCR2 in contused mouse and human skin, compared with intact skin. At postmortem there were no remarkable changes in CXCL1 and CXCR2 mRNA levels in contused mouse skin. Increased mRNA expression was observed in contused mouse skin up to 96 h and 72 h after death for CXCL1 and CXCR2 respectively. In human samples of wounded skin, increased CXCL1 mRNA levels were detected up to 48 h after autopsy in all 5 cases, while increased CXCR2 mRNA levels were observed 48 h after autopsy in 4 of 5 cases. These findings suggest that the levels of CXCL1 and CXCR2 mRNA present in contused skin can be used as potential markers for a vital reaction in forensic practice.

Vitality and wound-age estimation in forensic pathology: review and future prospects

Determining the age of a wound is challenging in forensic pathology, but it can contribute to the reconstruction of crime scenes and lead to arrest of suspects. Forensic scholars have tended to focus on evaluating wound vitality and determining the time elapsed since the wound was sustained. Recent progress in forensic techniques, particularly high-throughput analyses, has enabled evaluation of materials at the cellular and molecular levels, as well as simultaneous assessment of multiple markers. This paper provides an update on wound-age estimation in forensic pathology, summarizes the recent literature, and considers useful additional information provided by each marker. Finally, the future prospects for estimating wound age in forensic practise are discussed with the hope of providing something useful for further study.

Skin wounds vitality markers in forensic pathology: An updated review

Wound age evaluation is one of the most challenging issues in forensic pathology. In the first minutes or hours, standard histological examination may not determine whether the wound was inflicted in the pre- or post-mortem period. While red blood cell infiltration is classically considered as a sign of vital reaction, several studies have shown that extravasation of blood cells may also occur after death and cannot be used as a reliable marker in the diagnosis of wound vitality. Numerous studies about wound vitality are available in the literature. They have evaluated markers involved in coagulation or inflammation, using various methods such as enzymology, molecular biology or immunohistochemistry. In this update, we first introduce some methodological principles. Then, we review the main studies available in the literature. Immunohistochemistry seems to be the most valuable method, given its easy application and the possibility to analyse the localization of the molecules of interest. Some markers are promising, such as CD15, TNFα, IL-6, IL-1β, TGFα or TGFβ1. Prior to their application in daily practice, these early results need to be confirmed with other studies, conducted by independent teams and integrating multiple controls. Most notably, the antibodies have to be tested in numerous post-mortem wounds. Indeed, a critical risk of overexpression in post-mortem wounds is present. Some promising markers have been later invalidated because of post-mortem false positivity. Finally, optimal sensitivity and specificity values could probably be reached by combining several markers, validated by large groups of pre- and post-mortem wounds.

Detection of endothelial progenitor cells in human skin wounds and its application for wound age determination

Endothelial progenitor cells (EPCs), a newly identified cell type, are bone marrow-derived progenitor cells that co-express stem cell markers and vascular endothelial growth factor (VEGF) receptor (Flk-1). In this study, a double-color immunofluorescence analysis was carried out using anti-CD34 and anti-Flk-1 antibodies to examine the time-dependent appearance of EPCs, using 52 human skin wounds with different wound ages (Group I, 0-1 days; Group II, 2-6 days; Group III, 7-14 days; and Group IV, 17-21 days). In wound specimens with an age of less than one day, CD34(+)/Flk-1(+) EPCs were not detected. EPCs were initially observed in wounds aged two days, and their number was increased in lesions with advances in wound age. In morphometrical analysis, the average number of EPCs was the highest in the wounds of Group III. Especially, 20 out of 21 wounds aged 7-12 days had >20 EPCs, and all wound samples with postinfliction intervals of 14-21 days had <15 EPCs. These observations at least showed that >20 EPCs would indicate a wound age of 7-12 days. Taken together, our observations indicate the detection of EPCs would be useful for wound age determination.