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Slough is a well-known feature of non-healing wounds. This pilot study aims to determine the proteomic and microbiologic components of slough as well as interrogate the associations between wound slough components and wound healing. Ten subjects with slow-to-heal wounds and visible slough were enrolled. Aetiologies included venous stasis ulcers, post-surgical site infections and pressure ulcers. Patient co-morbidities and wound healing outcome at 3-months post-sample collection was recorded. Debrided slough was analysed microscopically, through untargeted proteomics, and high-throughput bacterial 16S-ribosomal gene sequencing. Microscopic imaging revealed wound slough to be amorphous in structure and highly variable. 16S-profiling found slough microbial communities to associate with wound aetiology and location on the body. Across all subjects, slough largely consisted of proteins involved in skin structure and formation, blood-clot formation and immune processes. To predict variables associated with wound healing, protein, microbial and clinical datasets were integrated into a supervised discriminant analysis. This analysis revealed that healing wounds were enriched for proteins involved in skin barrier development and negative regulation of immune responses. While wounds that deteriorated over time started off with a higher baseline Bates-Jensen Wound Assessment Score and were enriched for anaerobic bacterial taxa and chronic inflammatory proteins. To our knowledge, this is the first study to integrate clinical, microbiome, and proteomic data to systematically characterise wound slough and integrate it into a single assessment to predict wound healing outcome. Collectively, our findings underscore how slough components can help identify wounds at risk of continued impaired healing and serves as an underutilised biomarker., (© 2024 The Authors. Wound Repair and Regeneration published by Wiley Periodicals LLC on behalf of The Wound Healing Society.)

Background: A phase 3b, open-label, multicenter, expanded-access study (NCT04123548) evaluated safety and clinical outcomes of StrataGraft treatment in adults with deep partial-thickness thermal burns with intact dermal elements., Methods: Adult patients with 3 % to < 50 % total body surface area burns were treated with a single application of ≤ 1:1 meshed StrataGraft and followed for 24 weeks. Primary endpoint was count and percentage of patients with treatment-emergent adverse events (TEAEs). Secondary endpoints included confirmed wound closure (WC) at Week 12, durable WC at Week 24, time to WC, scar evaluation, and wound infection-related events., Results: Fifty-two patients with 96 treatment sites were enrolled. Pruritus was the most common TEAE (22 patients [42.3 %]). Twenty serious TEAEs occurred in 10 patients (19.2 %); none were related to StrataGraft. There were 4 (7.7 %) deaths (aspiration, myocardial infarction, self-injury, Gram-negative rod sepsis); none were related to StrataGraft. Confirmed WC was achieved by Week 12 in 33 patients (63.5 %; 95 % CI: 50.4-76.5 %) and 69 treatment sites (71.9 %; 95 % CI: 62.9-80.9 %). Durable WC was achieved by Week 24 in 29 patients (55.8 %; 95 % CI: 42.3-69.3 %) and 58 treatment sites (60.4 %; 95 % CI: 50.6-70.2 %)., Conclusions: StrataGraft demonstrated clinical benefit. Safety data were consistent with previously reported findings., Competing Interests: Declaration of Competing Interest James H. Holmes IV: Equity positions in Abbott Labs, AbbVie, Change Healthcare Inc, and Imbed Biosciences. Consultant for Avita Medical and has received research support from Avita Medical, Mallinckrodt Pharmaceuticals/Stratatech, SpectralMD, and Keranetics. Jeffrey W. Shupp: Research funding from Mallinckrodt Pharmaceuticals, Avita Medical, Urgo Medical, ACell, and Kerecis. JWS has been a consultant for Integra LifeSciences and Avita Medical. Tracee Short: Participated in the clinical advisory boards for Avita Medical, Mallinckrodt Pharmaceuticals, Synergy Biologics, Polynovo, and KCI. Victor C. Joe: Participated in a Mallinckrodt Pharmaceuticals Advisory Board relating to StrataGraft. Jeffrey Litt: Participated in the speaker bureau for Acelity/3AM (ended) and advisory board for Vericel (ended). Joshua Carson: Received research funding from Mallinckrodt Pharmaceuticals and the Biomedical Research and Development Authority (BARDA) and personal fees from Integra LifeSciences, Avita Medical, and Mallinckrodt Pharmaceuticals. Jeffrey E. Carter: Equity positions in PermeaDerm, Inc and is a consultant for Avita Medical. Research support from Avita Medical, SpectralMD, and Keranetics. Lucy Wibbenmeyer: Received research funding from Mallinckrodt Pharmaceuticals, Mediwound, and Biomedical Research and Development Authority (BARDA) and consultant fees from Vericel, Allosource, and Mallinckrodt Pharmaceuticals. Helen Hahn: Previous employee of Mallinckrodt Pharmaceuticals. Janice M. Smiell: Previous employee of Mallinckrodt Pharmaceuticals. Randi Rutan: Previous employee of Mallinckrodt Pharmaceuticals. Richard Wu: Employee of Mallinckrodt Pharmaceuticals. Angela L. F. Gibson: Received grant/research support from Mallinckrodt Pharmaceuticals., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Electrostimulation (ES) therapy for wound healing is limited in clinical use due to barriers such as cumbersome equipment and intermittent delivery of therapy., Methods: We adapted a human skin xenograft model that can be used to directly examine the nanogenerator-driven ES (NG-ES) effects on human skin in vivo-an essential translational step toward clinical application of the NG-ES technique for wound healing., Results: We show that NG-ES leads to rapid wound closure with complete restoration of normal skin architecture within 7 days compared to more than 30 days in the literature. NG-ES accelerates the inflammatory phase of wound healing with more rapid resolution of neutrophils and macrophages and enhances wound bed perfusion with more robust neovascularization., Conclusion: Our results support the translational evaluation and optimization of the NG-ES technology to deliver convenient, efficient wound healing therapy for use in human wounds., (© 2021. The Author(s).)

Surgery is the definitive treatment for burn patients who sustain full-thickness burn injuries. Visual assessment of burn depth is made by the clinician early after injury but is accurate only up to 70% of the time among experienced surgeons. Collagen undergoes denaturation as a result of thermal injury; however, the association of collagen denaturation and cellular death in response to thermal injury is unknown. While gene expression assays and histologic staining allow for ex vivo identification of collagen changes, these methods do not provide spatial or integrity information in vivo. Thermal effects on collagen and the role of collagen in wound repair have been understudied in human burn models due to a lack of methods to visualize both intact and denatured collagen. Hence, there is a critical need for a clinically applicable method to discriminate between damaged and intact collagen fibers in tissues. We present two complementary candidate methods for visualization of collagen structure in three dimensions. Second harmonic generation imaging offers a label-free, high-resolution method to identify intact collagen. Simultaneously, a fluorophore-tagged collagen-mimetic peptide can detect damaged collagen. Together, these methods enable the characterization of collagen damage in human skin biopsies from burn patients, as well as ex vivo thermally injured human skin samples. These combined methods could enhance the understanding of the role of collagen in human wound healing after thermal injury and potentially assist in clinical decision-making., (© 2020 The Wound Healing Society.)

Translation of wound healing research is limited by the lack of an appropriate animal model, due to the anatomic and wound healing differences in animals and humans. Here, we characterize healing of grafted, full-thickness human skin in an in vivo model of wound healing. Full-thickness human skin, obtained from reconstructive operations, was grafted onto the dorsal flank of NOD.Cg-Kit W41J Tyr + Prkdc scid Il2rg tm1Wjl /ThomJ mice. The xenografts were harvested 1 to 12 weeks after grafting, and histologic analyses were completed for viability, neovascularization, and hypoxia. Visual inspection of the xenograft shows drying and sloughing of the epidermis starting at week four. By week 12, the xenograft appears healed but has lost 63.05 ± 0.24% of the initial graft size. There is histologic evidence of epidermolysis as early as 2 weeks, which progresses until week 4, when new epidermis appears from the wound edges. Epidermal regeneration is complete by week 12, although the epidermis appears hypertrophied. An initial increase of infiltrating immune mouse cells into the xenograft normalizes to baseline 6 months after grafting. Neovascularization, as evidenced by positive staining for the proteins human CD31 and alpha smooth muscle actin, is present as early as 2 weeks after grafting at the interface between the xenograft and the mouse tissue. CD31 and alpha smooth muscle actin staining increased throughout the xenograft over the 12 weeks, leading to greater viability of the tissue. Likewise, there is increased Hypoxia Inducible Factor 1-alpha expression at the interface of viable and nonviable tissue, which suggest a hypoxia-driven process causing early graft loss. These findings illustrate human skin wound healing in an ischemic environment, providing a timeline for use of full thickness human skin after grafting in a murine model to study mechanisms underlying human skin wound healing., (© 2020 The Wound Healing Society.)

Background: Visual assessment of burn wound appearance is the standard of care to determine the depth of thermal injury but often incorrectly predicts wound healing potential. Histologic evaluation of hematoxylin and eosin (H&E) stained burn tissue is prone to subjectivity and is challenging for the novice. Lactate dehydrogenase (LDH) staining may offer a simplified and consistent technique to identify burn tissue viability., Methods: Thirty tissue samples were obtained from 6 patients undergoing surgical excision for clinically determined deep partial thickness or full thickness burns. Tissues were stained with H&E or LDH. Each specimen was scored by 3 individuals with varying levels of skill in histologic interpretation using a standardized checklist at 2 distinct time points., Results: Agreement within raters was highest for the expert rater and lowest for the novice; however, the LDH stained tissue method had improved agreement for an experienced burn surgeon and novice. Agreement between raters was greater for the LDH stained samples which were determined to have greater viability than the corresponding H&E section in 100% of samples scored by the expert and in 80% for the novice clinician., Conclusion: LDH staining offers a more consistent measure of tissue viability that can be used by experienced and novice clinicians., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Wound cleansing agents are routine in wound care and preoperative preparation. Antiseptic activity intends to prevent contaminating microbes from establishing an infection while also raising concerns of cytotoxicity and delayed wound healing. We evaluated the cytotoxicity of five clinically used wound cleaning agents (saline, povidone iodine, Dove® and Dial® soaps, and chlorhexidine gluconate [CHG]) using both an ex vivo and in vivo human skin xenograft mouse model, in contrast to classical in vitro models that lack the structural and compositional heterogeneity of human skin. We further established an ex vivo wound contamination model inoculated with ~100 cells of Pseudomonas aeruginosa or Staphylococcus aureus to evaluate antimicrobial efficacy. Scanning electron microscopy and confocal microscopy were used to evaluate phenotypic and spatial characteristics of bacterial cells in wound tissue. CHG significantly reduced metabolic activity of the skin explants, while all treatments except saline affected local cellular viability. CHG cytotoxicity persisted and progressed over 14 days, impairing wound healing in vivo. Within the contamination model, CHG treatment resulted in a significant reduction of P. aeruginosa wound surface counts at 24 h post‐treatment. However, this effect was transient and serial application of CHG had no effect on both P. aeruginosa or S. aureus microbial growth. Microscopy revealed that viable cells of P. aeruginosa reside deep within wound tissue post‐CHG application, likely serving as a reservoir to re‐populate the tissue to a high bioburden. We reveal concerning cytotoxicity and limited antimicrobial activity of CHG in human skin using clinically relevant models, with the ability to resolve spatial localization and temporal dynamics of tissue viability and microbial growth. [ABSTRACT FROM AUTHOR]