Vitality and time course of wounds

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.

Predictive accuracy of histopathological profile and immunohistochemical markers for the aging of abrasion: an autopsy-based study

Wound age estimation is a crucial medicolegal task for forensic pathologists. The main objective of the current study was to evaluate the ability of the histopathological profile and immunohistochemical markers (CD14 and IL-8) to predict the age of abrasion and, furthermore, identify the relationship between the histopathological profile and immunohistochemical markers in abrasion aging. The study involved postmortem cases (n = 246) of abrasion injuries in which the injury infliction time was known. The test skin samples were taken from the abrasion site, and an adjacent area of uninjured skin was sampled for control. Hematoxylin and eosin stain was applied to tissue sections for the histopathological analysis. The semi-quantitative evaluation was made for expressing immunohistochemical markers CD14 and IL-8 on the infiltrating inflammatory cells. The study showed that the age of abrasion was significantly higher (p < 0.05) among the cases with positive staining than those with negative staining for both CD14 and IL-8. Additionally, the study found a significant association between the age of the abrasion and the IHC staining for IL-8. However, no significant association was seen between the age of abrasion and the CD-14 IHC staining. The odds ratio (95% confidence interval) for more than 72 h of the age of abrasion was compared to 0 to 72 h of the age of abrasion. The odds ratios were 39.00 (4.177-364.13) for the predominant mononuclear cell infiltration and 84.50 (9.287-768.814) for cases with the appearance of fibroblast, granulation tissue, and collagen deposition when compared to an unremarkable change on histopathological examination. Positive staining of immunohistochemical markers CD14 and IL-8 for the age of abrasion of more than 72 h showed a sensitivity of 40% and 80.95%, respectively, and specificity of 71.6% and 52.5%, respectively. The quantification of the histopathological changes of predominant mononuclear cell infiltration and the appearance of fibroblast, granulation tissue formation, and collagen deposition showed a significant correlation for the age of abrasion of more than 72 h. The immunohistochemical analysis revealed IL-8 as a more accurate marker than CD14 in identifying abrasions older than 72 h.

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.

Application of P/VB staining to identify antemortem injury in a decomposed cadaver

It is challenging in forensic pathology to determine whether an injury is formed antemortem or postmortem in putrefied tissues. Hematoxylin-eosin (HE) staining fails to work in highly decomposed corpses. Ponceau/Victoria blue B (P/VB) staining is usually used to show collagen fibers and muscles. Here, we used P/VB to show antemortem laceration injury on the scalp in a severely decomposed cadaver 1.5 years after death. This method is a simple and alternative method for the diagnosis of antemortem 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.

Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans

We provide here an overview of the state of applied techniques in the estimation of the early period of the postmortem interval (PMI). The biological methods included consist of body cooling, CSF potassium, body cooling combined with CSF potassium, and tissue autolysis. For each method, we present its application in human and veterinary medicine and provide current methodology, strengths, and weaknesses, as well as target areas for improvement. We examine current and future molecular methods as they pertain to DNA and primarily to messenger RNA degradation for the estimation of the PMI, as well as the use of RNA in aging wounds, aging blood stains, and the identification of body fluids. Various types of RNA have different lengths, structures, and functions in cells. These differences in RNAs determine various intrinsic properties, such as their half-lives in cells, and, hence, their decay rate as well as their unique use for specific forensic tests. Future applications and refinements of RNA-based techniques provide opportunities for the use of molecular methods in the estimation of PMI and other general forensic applications.

Comparative histological analysis of the skin for forensic investigation of some animal species

Macroscopical and histological analysis of the skin is fundamental in both human and veterinary forensic investigations. However, databases of differential skin histology of various animal species are rare. The aim of the present study is to identify species-specific differential histological features of the skin that could be used in forensic investigations including animal identification. For this purpose, skin specimens were collected from the neck region of various farm animals including buffalo, cow, camel, sheep, goat, dog, and donkey, and were processed for histological analysis. Our comparative analysis revealed specific histological features in the skin that could differentiate between the studied animal species. The epidermis layer of the skin was very thick in buffalo, intermediate in cow, sheep, goat, dog, and donkey, but very thin in camel. The papillomatous epidermis was very frequent in buffalo, but very rare in cow. In the dermis layer of the skin, four structures were located which showed differential features between the studied animal species: the papillary layer, which was thick in buffalo, camel, sheep, dog, and donkey but thin in cow and goat. The sweat glands, which were few in buffalo, cow, goat, and dog, but numerous and deeply located in the dermis of sheep; they were individually located in all studied animals except in camel and donkey they were arranged in clusters. The hair follicles were characteristic for the skin of sheep as they were present at two different levels in the dermis with simple and compound hair follicles. The sebaceous glands were large and multi-lobular in buffalo, but small and uni-lobular in cow and camel. The hypodermis layer of the skin was very thick in sheep and goat in contrast to all other analyzed animals. In conclusion, the present study provides comprehensive information on the differential histological features of the skin of seven different domestic animal species that could be used as a key in forensic investigations.

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.

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.

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.

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.

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.

Look before washing and cleaning: A caveat to pathologists and anthropologists

Partially or totally skeletonized bodies are undoubtedly the most challenging scenario to deal with for forensic pathologists and anthropologists. Indeed, in such cases, being able to figure out the cause and manner of death is often tricky. Human remains require to be washed and cleaned before a thorough assessment of any signs of trauma. However, bones and any fragment of more or less putrefied soft tissues may be home to crucial traces for investigative purposes. They are often located in the context of apparently meaningless dirt and, sometimes they are even invisible to the naked eye. Therefore, their careless cleaning inevitably leads to an unintentional loss of such traces with a negative impact on subsequent investigations. For these reasons before proceeding with cleaning, exhaustive examination and sampling must be carried out. In particular fragments of soft tissues, even if putrefied, are absolutely not to be considered as a hindrance for forensic purposes, since they could still provide valuable information after histological examination. Finally, forward-thinking professionals should think about the possible presence of exogenous micro-traces of forensic concern and collect specimens to be analyzed through in-depth analyses, such as Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM/EDX). The present series of cases demonstrates that crucial forensic information can be obtained through the analysis of apparently meaningless residues and even of micro-traces not visible to the naked eye and mixed with trivial dirt.

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.

Novel insights into wound age estimation: combined with "up, no change, or down" system and cosine similarity in python environment

Wound age estimation is a complex, multifactorial issue. It is considered to have great practical significance that combining multi-biomarkers and multi-methods for injury time estimation. We optimized our earlier "up, no change, or down" model by adding data on the expression levels of mRNAs encoding ABHD2, MAD2L2, and ARID5A, and we converted the relative quantitative expression levels of seven genes into a vector rather than a color model. We used Python to derive the cosine similarity (CS) between a test set and the vector matrix; the highest similarity most accurately reflected the injury time. For the optimized model, the internal and external verifications were approximately 0.71 and 0.66, respectively. The good double-blinded results indicated that the model was stable and reliable. In summary, we used a vector matrix and cosine similarities derived by Python to mine the levels of genes expressed in contused skeletal muscle. We are the first to combine several biomarkers and methods for wound age estimation.

[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.

Regulation of miRNAs as new tool for cutaneous vitality lesions demonstration in ligature marks in deaths by hanging

This study aims to demonstrate that the application of miRNA expression in forensic pathology, in cases of hanging, applying the method on skin samples. The proposed investigative protocol allowed us to highlight a different miRNA expression in the skin ligature marks of subjects who died by hanging compared to healthy skin control samples. The results obtained showed an increase in the expression of miRNAs recognized as regulators of the inflammatory response in skin lesions such as miR125a-5p and miR125b-5p. Furthermore, overexpression of additional miRNAs - miR214a-3p, miR128-3p, miR130a-3p, and miR92a-3p - with anti-inflammatory activity was highlighted. It was possible to document a statistical significance to control skin samples only for miR103a-3p (p < 0.05), miR214-3p and miR92a-3p (p < 0.01) The upregulation of miR222-3p and miR150-5p, respectively related to mast-cell activation and neutrophils after the application of traumatic stimuli supports the immunohistochemical data showed in literature. The diagnostic accuracy of miRNAs could expand the range of diagnostic tools available in the assessment of the vitality of a lesion.

Histopathological, immunohistochemical, and molecular studies for determination of wound age and vitality in rats

In forensic medicine, it is vital to verify with the best attainable accuracy once injuries occurred during vital or post-mortem conditions. An immunohistochemical study was carried out to examine the time-dependent expression of macrophage-specific gene CD68 (cluster of differentiation 68), alpha-smooth muscle actin (α-SMA), and vascular endothelial growth factor (VEGF) in different skin wound timings (0, 1, 3, 5, 7, and 14 days) in rats. Histopathological studies were performed to assess the wound age and vitality. Eighteen male albino Wister rats (weighing 170-200 g) were used for wound induction. Rats (n = 3) were euthanised at 0, 1, 3, 5, 7, and 14 days from the starting point of wound induction. Histopathological examination showed that the epidermal re-epithelialisation was completed 14 days after skin incision. The inflammatory phase was recorded during the first 3 days of healing and reached the maximum levels at 5 days, then declined after 7 days, and completely removed at 14 days. The beginning of the proliferative phase was dated to day 3 and the peak at days 5 and 7. The initiation of the granulation tissue formation and remodelling phase of the healing process was observed 5 days after wounding. By immunohistochemical staining, negative VEGF gene expressions at early stages (0-3 days) were observed, as well as neither CD68+ macrophages nor α-SMA+ myofibroblast cells were detected. By increasing the wound ages (5-7 days), granulation tissue and angiogenesis were observed, with the migration of macrophages and fibroblast, which expressed VEGF, CD68, and α-SMA positive reaction. Time-dependent expression of the above markers suggested that they would be useful indicators for the determination of wound age. Both VEGF and transforming growth factor-beta 1 (TGFb1) mRNA levels were determined in different skin wound ages. The transcription of TGFb1 and VEGF increased shortly after wounding, until post-wounding day 7. It then declined constantly, reaching minimal values on day 14.

Histologic and radiological analysis on bone fractures: Estimation of posttraumatic survival time in skeletal trauma

In antemortem fractures, the estimation of the amount of time that has lapsed between the traumatic event and eventual death (the socalled 'posttraumatic survival time' or PTST) can have substantial implications in legal proceedings. It might for instance help to corroborate witness testimonies, to reconstruct the chain of events leading to eventual death or to establish a sequence when multiple traumata in a single individual are encountered. However, PTST estimation of bone trauma is impeded by a myriad of theoretical and practical issues, and is therefore almost invariably considered challenging. A few years ago, a method that combines radiological and histological analysis of fractures to estimate the minimum amount of lapsed PTST in skeletonized remains was proposed. This study aims to test its accuracy on a set of five rib fractures and four skull lesions fractures with known and varying amounts of posttraumatic survival time. In addition, it explores the differences between the assessment on ribs and skull bones and it expands on the proposed method by including computed tomography (CT) scanning. Using conventional radiology and histology, the minimum amount of PTST was accurately estimated in 8 out of 9 of the cases (89%). The one discrepancy between the estimated and known PTST was minimal, being just one day. The precision of the method diminishes as healing advances. It was noted that skull lesions showed less advanced and less well-developed healing features than the lapsed PTST would suggest. Of the three used modalities, conventional radiology proved to be the least accurate. CT scanning proved to be a valuable, sometimes even superior alternative to conventional radiology. Histology was superior to both conventional radiology and CT scanning. The results of our study illustrate the potential of the combined application of radiology and histology to estimate the PSTS in skeletonized human fractures.

Exiting the limbo of perimortem trauma: A brief review of microscopic markers of hemorrhaging and early healing signs in bone

The assessment and interpretation of the timing of skeletal trauma can be of extreme difficulty in post-mortem specimens, especially because of post-mortem processes and taphonomic events. The chronological diagnosis of bone trauma, consisting usually in the gross distinction between antemortem, perimortem and post-mortem, is based almost uniquely on macroscopic and morphologic parameters in the anthropological field. However, both the interference of taphonomy and the scarce persistence of specific features indicating vitality (meaning etymologically "produced in life") and/or some very early bone healing reactions, make it extremely difficult. In this perspective, it is important not only to distinguish between peri and post-mortem lesions, but also to interpret perimortem lesions with respect to vitality and time elapsed since the trauma which may change the course of the investigations. And techniques of forensic pathology applied to forensic anthropology can come in extremely handy. If any traces of vital blood extravasation, haemorrhage, hematoma, inflammation, and biomarkers of early healing reaction are found in the bone tissue of a skeletal lesion (regardless the state of preservation of the body), then can they be used as a diagnostic tool or marker of vitality for that lesion? In these terms, vital reactions like bleeding or any early sign of bone healing can be the only evidence for demonstrating that a traumatic event was prior the death. Nevertheless, very little information, or research for that matter, is available in literature concerning persistence and detectability of vitality markers during the bone decomposition process. A fundamental point for properly determining the vitality of a fracture and estimating the post-traumatic time interval in skeletal lesions is the physio-pathological picture of the very initial healing process. This article attempts to provide a review of the physiopathological current knowledge available and applicable to osteology.

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.

Histological Characteristics of Bruises with Different Age

BACKGROUND:

In forensics bruises as injuries take an important part in the interpretation of the causes of death. Since activating the inflammatory response of the body in their formation, histological analysis of the bruised tissue can provide data on the determination the time when the injury occurred.

AIM:

The aim of this study is to compare the histological features of 1-day and 5-days old bruises.

MATERIAL AND METHODS:

Bruised human skin samples, 1-day old in group A and 5-day-old in group B, obtained at autopsy from individuals who died from a violent death, were analyzed in this study. The qualitative microscopic analysis was performed on serial paraffin sections of tissues stained with Hematoxylin-eosin and Pearls Prussian Blue method, using a light microscope connected to a digital camera.

RESULTS:

Qualitative histological analysis of the studied group A presented with fresh bruises, less than 24 hours old, showed ruptured smaller vessels and extravasated red blood cells in the connective tissue of the skin, with subsequent expansion and infiltration of fibrous septa of the skin. In the area of bleeding an initial infiltration by macrophages was observed. In the studied group B, presented with bruises 3-7 days old, histological analysis showed a marked presence of hemosiderin-laden macrophages and presence of hematoidin granules in the area of bleeding, as well as ruptured small blood vessels and red blood cells extravasation in the dilated fibrous septa.

CONCLUSION:

A detailed analysis of tissue changes in bruises every day from the initiation until their recovery, a detailed description of the histological finding can be given, which will be supported in the precise determination of the age of the injuries themselves.

Development and Validation of a Technique for Casting Anatomical Features and Toolmarks

Time may elapse between examination of marks inflicted on the body and comparison with a potential weapon. Two-dimensional photographs may be inadequate for effective comparison of a three-dimensional mark with a putative instrument. Taking a cast and producing a positive image results in a lasting three-dimensional record. This project aimed to develop and demonstrate the accuracy of an easy technique for production of long-lasting positive images (using plaster of Paris and dental alginate). Casts of facial features of embalmed cadavers were used to produce a positive image of the face (death mask). Measurements of distances between facial anatomical landmarks were compared with measurements of distances between the same landmarks on the death masks to assess accuracy of reproduction. There were no significant differences between cadaver and death mask in 6 of 9 measurements, indicating this technique has high accuracy with less mobile facial features, but produces deformation of pliable features.

Determination of skin wound age by using cytokines as potential markers

Interleukin-1 beta (IL-1β), IL-6, tumour necrosis factor-alpha (TNF-α) and epidermal growth factor (EGF) play important roles in the wound healing process. In the present study, human wound specimens (n = 50) were collected from cases of death due to injuries from firearms, penetrating trauma by sharp objects and blunt trauma with a known time of injury and death identified by forensic autopsy. Full-thickness tissue specimens were obtained from injured skin sites, and equally sized intact tissues obtained from the same person were used as controls. Protein determination was performed using ELISA according to the Bradford method for each specimen, and results were provided for individual proteins. IL-1β levels did not reach statistical significance in any of the wound groups and were not markedly higher than those in the control group. However, IL-6 showed a biphasic pattern and reached statistical significance in the group with wounds less than 30 min old and in the group with wounds more than 18 h old. IL-6 was consistently higher in all wound groups than in the control group. TNF-α showed a statistically significant increase within the first 30 min and remained at a high level in all groups except for those with wounds 2-4 h old. On the other hand, EGF was high in all groups excluding those with wounds 2-4 h old and more than 18 h old, but statistical significance was not reached. Our results suggest that IL-6 and TNF-α in particular may be used as early-phase markers. We believe that IL-1β and EGF should be more extensively evaluated in further studies.

Dating of Acute and Subacute Subdural Haemorrhage: A Histo-Pathological Study

INTRODUCTION

Microscopic study of the organization of the Subdural Haemorrhage (SDH) verified against the time period can help us in the determination of its age which has serious medico-legal implications. Very few studies concerning the dating of SDH are present in the literature.

AIM

This study was conducted for dating the early subdural haemorrhage by routine histopathological stains.

MATERIALS AND METHODS

A prospective analytical study was conducted during July 2009 to December 2010. A total of 100 cases (50 males and 50 females) fulfilling the inclusion and exclusion criteria were included in this study. Routine histopathological staining of the subdural haematoma was done.

RESULTS

Correlation between the frequency of a given histomorphological phenomenon and the length of the Post-Traumatic Interval (PTI) was evidential. All the histomorphological features, when correlated with PTI groups, were found to be statistically significant, except for Polymorphonuclear Leukocytes (PMN).

CONCLUSION

We concluded that routine histopathology was reliable in the dating of early subdural haemorrhages.

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.

A novel, comprehensive, and reproducible porcine model for determining the timing of bruises in forensic pathology

PURPOSE

Calculating the timing of bruises is crucial in forensic pathology but is a challenging discipline in both human and veterinary medicine. A mechanical device for inflicting bruises in pigs was developed and validated, and the pathological reactions in the bruises were studied over time in order to identify gross and histological parameters that may be useful in determining the age of a bruise.

METHODS

The mechanical device was able to apply a single reproducible stroke with a plastic tube that was equivalent to being struck by a man. In each of 10 anesthetized pigs, four strokes that resulted in bruises were inflicted on the back. In addition, 2 control pigs were included in the study. The pigs were euthanized consecutively from 1 to 10 h after the infliction of bruises. Following gross evaluation, skin, and muscle tissues were sampled for histology.

RESULTS

Grossly, the bruises appeared uniform and identical to the tramline bruises seen in humans and pigs subjected to blunt trauma. Histologically, the number of neutrophils in the subcutis, the number of macrophages in the muscle tissue, and the localization of neutrophils and macrophages in muscle tissue showed a time-dependent response. Combining these parameters, bruises could be grouped as being either less than 4 h old or between 4 and 10 h of age. Gross lesions and changes in the epidermis and dermis were inconclusive with respect to time determination.

CONCLUSIONS

The model was reproducible and resembled forensic cases of bruises in pigs and humans. Therefore, the histological parameters are suitable for age determination of bruises in pigs and likely also in humans.

Identification and differential diagnosis of perimortem blunt force trauma in tubular long bones

The identification of perimortem injuries from human remains is crucial in the forensic evaluation of skeletal trauma. The purpose of this article is to review the criteria currently used by forensic experts for the identification and differential diagnosis of perimortem blunt force trauma in long bones. The mechanism of injury and the associated fracture pattern in long bones is discussed because it is fundamental in the forensic interpretation. The distinction between postmortem and perimortem fractures is based on the evidence of an osteogenic reaction. The first signs of healing can be detected macroscopically, radiographically, or histologically. Perimortem injuries may be distinguished from postmortem damage by examining certain attributes such as fracture angle and fracture margins. Additionally, the most commonly encountered taphonomic factors leading to postmorterm damage are described in order to alert the workers of the existence of such pitfalls that may perplex the forensic interpretation of skeletal trauma. Although the distinction of bone damage that occurred long after death from perimortem trauma is relatively easy, the differentiation of fractures inflicted shortly before death or soon after death may be difficult or even impossible.

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.

The time-dependent expression of α7nAChR during skeletal muscle wound healing in rats

The study on time-dependent expression of α7 nicotine acetylcholine receptor (α7nAChR) was performed by immunohistochemistry, Western blotting, and real-time PCR during skeletal muscle wound healing in rats. Furthermore, co-localization of α7nAChR with macrophage or myofibroblast marker was detected by double immunofluorescence. A total of 50 Sprague-Dawley male rats were divided into control and contusion groups (3 h, 6 h, 12 h, 1 day, 3 days, 5 days, 7 days, 10 days, and 14 days post-injury). In the uninjured controls, α7nAChR positive staining was observed in the sarcolemma and sarcoplasm of normal myofibers. In wounded specimens, a small number of polymorphonuclear cells, a number of macrophages and myofibroblasts showed positive reaction for α7nAChR in contused zones. Morphometrically, the average ratios of α7nAChR-positive cells were over 50 % from 3 to 10 days after contusion, and exceeded 60 % at 5 and 7 days post-injury. Besides, the positive ratios of α7nAChR were <50 % at the other posttraumatic intervals. By Western blotting analysis, the average ratio of α7nAChR protein expression maximized at 7 days after injury, which was >2.13. Similarly, the relative quantity of α7nAChR mRNA expression peaked at 7 days post-wounding as compared with control by real-time PCR detection, showing a relative quantity of >2.65. In conclusion, the expression of α7nAChR is upregulated and temporally distributed in macrophages and myofibroblasts during skeletal muscle wound healing, which might be closely involved in inflammatory response and fibrotic repair after injury. Moreover, α7nAChR is promising as a useful marker for wound age determination of skeletal muscle.

Forensic molecular pathology: its impacts on routine work, education and training

The major role of forensic pathology is the investigation of human death in relevance to social risk management to determine the cause and process of death, especially in violent and unexpected sudden deaths, which involve social and medicolegal issues of ultimate, personal and public concerns. In addition to the identification of victims and biological materials, forensic molecular pathology contributes to general explanation of the human death process and assessment of individual death on the basis of biological molecular evidence, visualizing dynamic functional changes involved in the dying process that cannot be detected by morphology (pathophysiological or molecular biological vital reactions); the genetic background (genomics), dynamics of gene expression (up-/down-regulation: transcriptomics) and vital phenomena, involving activated biological mediators and degenerative products (proteomics) as well as metabolic deterioration (metabolomics), are detected by DNA analysis, relative quantification of mRNA transcripts using real-time reverse transcription-PCR (RT-PCR), and immunohisto-/immunocytochemistry combined with biochemistry, respectively. Thus, forensic molecular pathology involves the application of omic medical sciences to investigate the genetic basis, and cause and process of death at the biological molecular level in the context of forensic pathology, that is, 'advanced molecular autopsy'. These procedures can be incorporated into routine death investigations as well as guidance, education and training programs in forensic pathology for 'dynamic assessment of the cause and process of death' on the basis of autopsy and laboratory data. Postmortem human data can also contribute to understanding patients' critical conditions in clinical management.

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

The timing of skin wounds is one of the most challenging problems in forensic pathology. In the first minutes or hours after infliction, histological examination fails to determine whether a wound was sustained before or after death. The aim of this study was to evaluate the use of three immunohistochemical markers (FVIIIra, CD15, and tryptase) for the interpretation of the timing of cutaneous stab wounds. We evaluated these markers in intravital wounds from autopsy cases (n = 12) and surgical specimens (n = 58). As controls, we used normal skin samples from autopsies (n = 8) and an original ex vivo surgical human model of recent postmortem wounds (n = 24). We found overexpression of FVIIIra in 100 % of vital wounds, but also in 53 % of the controls. The number of CD15-positive cells was higher in wound margins than in internal controls (p < 0.0001) and was significantly correlated with the time interval between incision and devascularization (p = 0.0005; minimal time for positivity, 9 min). Using the anti-tryptase antibody, we found that the mast cell degranulation rate was higher in wound margins (p < 0.0001) and correlated with the time interval (minimal time, 1 min). The sensitivity and specificity for the diagnosis of vitality were respectively 100 and 47 % for FVIIIra, 47 and 100 % for CD15, and 60 and 100 % for tryptase. The inter-observer agreement coefficients were 0.68 for FVIIIra, 0.90 for CD15, and 0.46 for tryptase. Finally, we demonstrated that these markers were not reliable in putrefied or desiccated specimens. In conclusion, CD15 and tryptase, but not FVIIIra, may be useful markers for differentiating recent antemortem from postmortem injuries.

Histological analysis of short-term vital reactions in skin wounds: potential applications in forensic work

In forensic medical work, in cases with homicide suspicion, it is important to be able to determine with the greatest possible precision when injuries occurred and whether during vital, or post-mortem conditions. Although several markers of vitality can be employed, it has been attested that components of the extra-cellular matrix, such as fibrin, are among the earliest to be evidenced. In the present study, the histological-histochemical Mallory's Trichrome staining method, previously selected was tested to determine the presence of vital reaction in Wistar rats through fibrin accumulation by testing three short reaction time intervals: 15, 30 and 60 minutes after the skin wound infliction. For all time intervals tested, including the shortest (15 minutes), the presence of fibrin at the edges of the skin wound was evidenced. The accumulation of fibrin was, nevertheless, more pronounced at 30 and 60 minutes after the wound. It could be concluded that fibrin is a good marker for vital reaction and that it can be detected very early, within a few minutes after the injury. It is proposed that histological method coupled to the histochemical staining technique here tested can be incorporated into routine forensic work as a tool for evidencing the existence or not of vital reaction.