A porcine model for pathomorphological age assessment of surgically excised skin wounds

Immunohistochemical study of CD31 and α-SMA expression for age estimation of porcine skin wounds

Age estimation of wounds in veterinary forensic investigations is based on the presence and amount of granulation tissue. However, accurate age assessment is challenging and new time-dependent markers are warranted to support and improve the current procedure. The objective of this study was to evaluate the expression of CD31-positive blood vessels and α-smooth muscle action (α-SMA)-positive myofibroblasts in granulation tissue in order to evaluate their value as markers for porcine wound age estimation in a veterinary forensic context. Immunohistochemical expression of CD31 and α-SMA in 14 experimental porcine skin wounds of different ages (4, 6, 8, 10, 18, 27 and 35 days) and 11 forensic porcine wound specimens (of unknown age) were evaluated. CD31-positive blood vessels and α-SMA-positive myofibroblasts were present in the granulation tissue in the experimental wounds at all time points. A significant decrease in the mean blood vessel counts was found in wounds aged 18, 27 and 35 days compared with wounds aged 6 days (P < 0.001), when assessing both the superficial and deep part of the wound bed. α-SMA expression was lower at 27 and 35 days post wounding compared with 6-18 days post wounding. Combined assessment of three parameters (mean blood vessel counts in the superficial and deep wound beds and α-SMA expression) could approximately specify the age of the wounds as either 6-18 days or ≥27 days. In two of the forensic cases a combination of the three parameters yielded results that were similar to the experimental wounds, indicating a wound age of 6-18 days or ≥27 days, respectively. In the remaining forensic cases a combination of the three parameters did not show the same expression pattern as in the experimental wounds. The results indicate that in some forensic cases the application of CD31 and α-SMA markers appeared to support the current procedure for porcine wound age estimation, but this must be combined with pathological characteristics.

Forensic necropsies of cattle: a study of Danish cases from 2010 to 2021 and a guideline for forensic examination of cattle

Forensic post-mortem examinations of animals are carried out on suspicion of violation of European and national legislation. In Denmark, and probably also in other countries with large-scale cattle production, cattle are regularly submitted for forensic assessment. Unfortunately, only few studies of forensic pathology in cattle are available. This paper presents a retrospective study of forensic case files on Danish cattle from January 2010 to December 2021. The case files were characterized with respect to types of lesion, age assessments of lesions and other parameters such as age and sex. A total of 118 forensic case files had been archived and related to 132 cattle (14 weeks-20 years of age; 68% female, 30% male and 2% unknown sex) with 228 lesions. Locomotor disorders constituted the majority of lesions. However, cachexia/emaciation, skin ulcerations and overgrowth of cornual horn were also frequent. Most lesions were chronic (91%) and age assessments for more than 2 weeks were stated for 79% of the lesions. This indicates that in Denmark at least, there is a need to consider how cattle with locomotor disorders are treated in a timely manner in order to avoid prolonged futile treatment and, thereby, suffering. Grossly visible reparative granulation tissue and new bone formation were present in lesions of 1-2 weeks and longer duration. However, all age assessments were stated in broad time intervals due to the lack of scientifically based forensic studies of age assessments of lesions in cattle. Therefore, to improve age assessments in forensic cattle cases, studies concerning the chronology of tissue reparation in cattle are warranted. We also present a guideline for the forensic examination of cattle.

The detection and prediction of surgical site infections using multi-modal sensors and machine learning: Results in an animal model

Introduction

Surgical Site Infection (SSI) is a common healthcare-associated infection that imposes a considerable clinical and economic burden on healthcare systems. Advances in wearable sensors and digital technologies have unlocked the potential for the early detection and diagnosis of SSI, which can help reduce this healthcare burden and lower SSI-associated mortality rates.

Methods

In this study, we evaluated the ability of a multi-modal bio-signal system to predict current and developing superficial incisional infection in a porcine model infected with Methicillin Susceptible Staphylococcus Aureus (MSSA) using a bagged, stacked, and balanced ensemble logistic regression machine learning model.

Results

Results demonstrated that the expression levels of individual biomarkers (i.e., peri-wound tissue oxygen saturation, temperature, and bioimpedance) differed between non-infected and infected wounds across the study period, with cross-correlation analysis indicating that a change in bio-signal expression occurred 24 to 31 hours before this change was reflected by clinical wound scoring methods employed by trained veterinarians. Moreover, the multi-modal ensemble model indicated acceptable discriminability to detect the presence of a current superficial incisional SSI (AUC = 0.77), to predict an SSI 24 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.80), and to predict an SSI 48 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.74).

Discussion

In sum, the results of the current study indicate that non-invasive multi-modal sensor and signal analysis systems have the potential to detect and predict superficial incisional SSIs in porcine subjects under experimental conditions.

Strong Antimicrobial and Healing Effects of Beta-Acids from Hops in Methicillin-Resistant Staphylococcus aureus-Infected External Wounds In Vivo

Staphylococcus (S.) aureus is an important causative agent of wound infections with increasing incidence in the past decades. Specifically, the emergence of methicillin-resistant S. aureus (MRSA) causes serious problems, especially in nosocomial infections. Therefore, there is an urgent need to develop of alternative or supportive antimicrobial therapeutic modalities to meet these challenges. Purified compounds from hops have previously shown promising antimicrobial effects against MRSA isolates in vitro. In this study, purified beta-acids from hops were tested for their potential antimicrobial and healing properties using a porcine model of wounds infected by MRSA. The results show highly significant antimicrobial effects of the active substance in both the powder and Ambiderman-based application forms compared to both no-treatment control and treatment with Framycoin. Moreover, the macroscopic evaluation of the wounds during the treatment using the standardized Wound Healing Continuum indicated positive effects of the beta-acids on the overall wound healing. This is further supported by the microscopic data, which showed a clear improvement of the inflammatory parameters in the wounds treated by beta-acids. Thus, using the porcine model, we demonstrate significant therapeutic effects of hops compounds in the management of wounds infected by MRSA. Beta-acids from hops, therefore, represent a suitable candidate for the treatment of non-responsive nosocomial tissue infections by MRSA.