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

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

Macrophage polarity and wound age determination.

We investigated the dynamics of the gene expression of M1 and M2 macrophage markers during skin wound healing in mice. Expression of M1-macrophage markers, such as Il12a, Tnf, Il6, Il1b, and Nos2 was upregulated after wounding and peaked at 1 or 3 days after injury, and that of M2-macrophage markers such as Mrc1, Cd163, Ccl17, Arg, and Tgfb1, peaked at 6 days after injury. Consistent with these findings, using triple-color immunofluorescence analysis revealed that F4/80+CD80+ M1 macrophages were more abundant than F4/80+CD206+ M2 macrophages on day 3 in mouse wound specimens, and that M2 macrophages were prominently detected in day 6 wounds. For application in forensic practice, we examined macrophage polarization using human wound specimens. The average ratios of CD68+iNOS+ M1 macrophages to CD68+CD163+ M2 macrophages (M1/M2 ratios) were greater than 2.5 for the wounds aged 2-5 days. Out of 11 wounds aged 1-5 days, five samples had the M1/M2 ratios of > 3.0. These observations propose that the M1/M2 ratios of 3.0 would indicate a wound age of 1-5 days as the forensic opinion. This study showed that M1 and M2 macrophages in human skin wound might be a promising marker for wound age determination.

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

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

A case of necrotizing fasciitis following intra-articular injections - Iatrogenic or spontaneous?

Here, we report a case of necrotizing fasciitis following intra-articular injection of hyaluronic acid. A 73-year-old female received intra-articular injections of hyaluronic acid due to arthralgia at the left shoulder and knee, and was found dead in her living room at one day. At the forensic autopsy, injection marks with bullae and erythema were found at the left shoulder and knee and liquefactive necrosis of muscle tissues was observed in the left but not right extremities. Histopathological examinations of the left upper arm and thigh revealed severe rhabdomyolysis with lots of bacterial clusters. Bacteriological examinations detected group A Streptococcus from intracardiac blood and affected muscle tissues. Postmortem biochemical analysis of blood showed escalated blood urea nitrogen (133.8 mg/dL), creatinine (4.57 mg/dL) and C-reactive protein (45.0 mg/dL). The cause of her death was diagnosed as streptococcal toxic shock syndrome (STSS). Moreover, it was suggested that the injection was inappropriately conducted and served as a portal of bacterial entry.