IQGAP1-mediated mechanical signaling promotes the foreign body response to biomedical implants.

The aim of this study was to further elucidate the molecular mechanisms that mediate pathologic foreign body response (FBR) to biomedical implants. The longevity of biomedical implants is limited by the FBR, which leads to implant failure and patient morbidity. Since the specific molecular mechanisms underlying fibrotic responses to biomedical implants have yet to be fully described, there are currently no targeted approaches to reduce pathologic FBR. We utilized proteomics analysis of human FBR samples to identify potential molecular targets for therapeutic inhibition of FBR. We then employed a murine model of FBR to further evaluate the role of this potential target. We performed histological and immunohistochemical analysis on the murine FBR capsule tissue, as well as single-cell RNA sequencing (scRNA-seq) on cells isolated from the capsules. We identified IQ motif containing GTPase activating protein 1 (IQGAP1) as the most promising of several targets, serving as a central molecular mediator in human and murine FBR compared to control subcutaneous tissue. IQGAP1-deficient mice displayed a significantly reduced FBR compared to wild-type mice as evidenced by lower levels of collagen deposition and maturity. Our scRNA-seq analysis revealed that decreasing IQGAP1 resulted in diminished transcription of mechanotransduction, inflammation, and fibrosis-related genes, which was confirmed on the protein level with immunofluorescent staining. The deficiency of IQGAP1 significantly attenuates FBR by deactivating downstream mechanotransduction signaling, inflammation, and fibrotic pathways. IQGAP1 may be a promising target for rational therapeutic design to mitigate pathologic FBR around biomedical implants.

The single-stage melolabial flap for internal lining of full thickness defects of the nasal ala.

BACKGROUND: Full-thickness defects of the nasal ala necessitate composite repair of the nasal lining, cartilage and soft tissue envelope. Repair of the nasal lining is particularly challenging due to access and geometry of this area. OBJECTIVE: To evaluate the melolabial flap as a single stage operation for repair of full-thickness nasal ala defects. METHODS: Retrospective study of seven adult patients with full-thickness nasal ala defects who underwent melolabial flap repair. Complications and operative technique were recorded and described. RESULTS: Of the seven patients who underwent melolabial flap repair, each had excellent coverage of the defect postoperatively. There were two cases of mild ipsilateral congestion, and no revision procedures performed. CONCLUSION: The melolabial flap is a versatile reconstructive option for repair of the internal lining of the nasal ala, and in our series there were no significant complications or revision procedures performed.

Comparing the Outcomes and Complication Rates of Biologic vs Synthetic Meshes in Implant-Based Breast Reconstruction: A Systematic Review.

OBJECTIVE: This systematic review evaluates all published studies comparing biologic and synthetic meshes in implant-based breast reconstruction (IBBR), to determine which category of mesh produces the most favorable outcomes. SUMMARY BACKGROUND DATA: Breast cancer is the most common cancer in women globally. Implant-based breast reconstruction is currently the most popular method of postmastectomy reconstruction, and recently, the use of surgical mesh in IBBR has become commonplace. Although there is a long-standing belief among surgeons that biologic mesh is superior to synthetic mesh in terms of surgical complications and patient outcomes, few studies exist to support this claim. METHODS: A systematic search of the EMBASE, PubMed, and Cochrane databases was performed in January 2022. Primary literature studies comparing biologic and synthetic meshes within the same experimental framework were included. Study quality and bias were assessed using the validated Methodological Index for Non-Randomized Studies criteria. RESULTS: After duplicate removal, 109 publications were reviewed, with 12 meeting the predetermined inclusion criteria. Outcomes included common surgical complications, histological analysis, interactions with oncologic therapies, quality of life measures, and esthetic outcomes. Across all 12 studies, synthetic meshes were rated as at least equivalent to biologic meshes for every reported outcome. On average, the studies in this review tended to have moderate Methodological Index for Non-Randomized Studies scores. CONCLUSION: This systematic review offers the first comprehensive evaluation of all publications comparing biologic and synthetic meshes in IBBR. The consistent finding that synthetic meshes are at least equivalent to biologic meshes across a range of clinical outcomes offers a compelling argument in favor of prioritizing the use of synthetic meshes in IBBR.

Current Treatment Landscape for Dystrophic Epidermolysis Bullosa: From Surgical Management to Emerging Gene Therapies and Novel Skin Grafts.

Epidermolysis bullosa is a genetic skin disorder characterized by blister formation from mechanical trauma. Dystrophic epidermolysis bullosa (DEB) is caused by mutations in the COL7A1 gene presenting as generalized blisters from birth, which can result in extensive scarring, alopecia, esophageal stenosis, corneal erosions, and nail dystrophy. This disease also often leads to pseudosyndactyly of the digits from the closure of webspaces, progressing to a "mitten hand" deformity. Although traditional and current treatment for DEB is largely supportive with wound care and iterative surgical pseudosyndactyly release, emerging gene therapies and novel skin grafts may offer promising treatment. Studies published in the early 2020s have used HSV-1 vectors expressing missing COL7A1 genes to restore collagen function. One of these treatments, B-VEC, is an HSV-1-based topical gene therapy designed to restore collagen 7 by delivering the COL7A1 gene, leveraging a differentiated HSV-1 vector platform that evades the patient's immune system response. Other work has been performed to retrovirally modify autologous keratinocytes, but limitations of this process include increased labor in harvesting and engineering autologous cells. This article provides an overview of DEB treatment with an emphasis on emerging gene therapies and novel skin grafts, especially as they pertain to pseudosyndactyly treatment.

Pullulan-Collagen hydrogel wound dressing promotes dermal remodelling and wound healing compared to commercially available collagen dressings.

Biological scaffolds such as hydrogels provide an ideal, physio-mimetic of native extracellular matrix (ECM) that can improve wound healing outcomes after cutaneous injury. While most studies have focused on the benefits of hydrogels in accelerating wound healing, there are minimal data directly comparing different hydrogel material compositions. In this study, we utilized a splinted excisional wound model that recapitulates human-like wound healing in mice and treated wounds with three different collagen hydrogel dressings. We assessed the feasibility of applying each dressing and performed histologic and histopathologic analysis on the explanted scar tissues to assess variations in collagen architecture and alignment, as well as the tissue response. Our data indicate that the material properties of hydrogel dressings can significantly influence healing time, cellular response, and resulting architecture of healed scars. Specifically, our pullulan-collagen hydrogel dressing accelerated wound closure and promoted healed tissue with less dense, more randomly aligned, and shorter collagen fibres. Further understanding of how hydrogel properties affect the healing and resulting scar architecture of wounds may lead to novel insights and further optimization of the material properties of wound dressings.

Risk Factors for Wound Complications After Soft Tissue Sarcoma Resection.

ABSTRACT: Soft tissue sarcomas are a heterogenous group of malignant tumors that represent approximately 1% of adult malignancies. Although these tumors occur throughout the body, the majority involved the lower extremity. Management may involve amputation but more commonly often includes wide local resection by an oncologic surgeon and involvement of a plastic surgeon for reconstruction of larger and more complex defects. Postoperative wound complications are challenging for the surgeon and patient but also impact management of adjuvant chemotherapy and radiation therapy. To explore risk factors for wound complications, we reviewed our single-institution experience of lower-extremity soft tissue sarcomas from April 2009 to September 2016. We identified 127 patients for retrospective review and analysis. The proportion of patients with wound complications in the cohort was 43.3%. Most notably, compared with patients without wound complications, patients with wound complications had a higher proportion of immediate reconstruction (34.5% vs 15.3%; P = 0.05) and a marginally higher proportion who received neoadjuvant radiation (30.9% vs 16.7%; P = 0.06).

Local Administration of Interleukin-1 Receptor Antagonist Improves Diabetic Wound Healing.

Impaired healing of the skin is a notable cause of patient morbidity and mortality. In diabetic individuals, dysregulated inflammation contributes to delayed wound healing. Specific immunomodulatory agents may have a role in the treatment of diabetic wounds. One of these molecules is interleukin-1 receptor antagonist (Anakinra; Amgen Corp.). Although interleukin-1 receptor antagonist (Anakinra; Amgen Corp.) is approved by the Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis and neonatal-onset multisystem inflammatory disease, little is known about the local use this drug in cutaneous wound healing. Therefore, the aim of this study is to determine the effect of locally administered interleukin-1 receptor antagonist on delayed wound healing, specifically, in a diabetic mouse model. Two 6-mm full-thickness wounds were created on the dorsa of diabetic (db/db) mice and stented. One-hour postwounding, wound margins were subcutaneously injected with either (1) low-dose interleukin-1 receptor antagonist in a gelatin-transglutaminase gel vehicle or (2) the gel vehicle only. Wounds were imaged on days 0, 7, 14, and 21 postwounding, and wound area was determined. Wound biopsies were collected on day 21 and immunohistochemically stained for neutrophil and macrophage infiltration. Wounds treated with interleukin-1 receptor antagonist had significantly smaller wound area than nontreated wounds on day 7 and day 14 postwounding. Treated wounds also showed significantly less neutrophil and macrophage infiltration. These findings support the hypothesis that interleukin-1 receptor antagonist may have an important role in cutaneous wound healing, possibly by promoting successful resolution of acute inflammation and hence accelerating wound closure. Thereby, administration of IL-1Ra may be useful in the treatment of nonhealing wounds.

Prevention of Postsurgical Lymphedema by 9-cis Retinoic Acid.

OBJECTIVE: To determine the effect of 9-cis retinoic acid (9-cis RA) on postsurgical lymphedema. BACKGROUND: 9-cis RA promotes lymphangiogenesis in vitro and in vivo and has promise as a therapeutic agent to limit the development of postsurgical lymphedema. METHODS: Lymphedema was induced in the right hind limb after a single fraction of 20 Gy radiation, popliteal lymphadenectomy, and lymphatic vessel ablation. Postoperatively, mice were randomly divided in to 2 groups that received daily intraperitoneal injections of either (1) an oil-based vehicle solution (control) or (2) 0.08 mg/kg of 9-cis RA dissolved in a vehicle solution. Outcome measures included paw thickness, lymphatic drainage, and lymphatic vessel density as measured by podoplanin immunohistochemistry and whole mount skin analysis. RESULTS: Using our combined injury protocol, postsurgical lymphedema was observed 89% of the time. 9-cis RA-treated animals had less early postsurgical edema and significantly less paw lymphedema compared with vehicle-treated animals at all time-points (P < 0.001). 9-cis RA-treated animals had significantly faster lymphatic drainage as measured by indocyanine green clearance and increased lymphatic vessel density as measured by podoplanin immunohistochemistry (P < 0.001) and whole mount skin analysis (P < 0.05). CONCLUSIONS: We have developed a highly reproducible model of secondary lymphedema and have demonstrated that 9-cis RA significantly prevents postsurgical lymphedema. Treatment with 9-cis RA is associated with increased lymphatic clearance and lymphangiogenesis. Because 9-cis RA (alitretinoin) is already approved for clinical use by the US Food and Drug Administration for other conditions, it has the potential to be repurposed as a preventative agent for postsurgical lymphedema in humans.

Diagnosis and Management of Orbital Compartment Syndrome in Burn Patients - a Systematic Review.

Orbital compartment syndrome is a poorly understood complication of acute burns. The purpose of this systematic review is to summarize the literature describing orbital compartment syndrome in burn patients to provide greater detail on risk factors and guide management of this morbid condition. A systematic review of the PubMed, Embase, and Cochrane Library databases was performed in June 2023 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Study quality was assessed using two validated scoring systems. After removing duplicates, 303 unique articles were reviewed and 8 met inclusion criteria. All publications were retrospective. Most studies considered intraocular pressure >30-40mmHg as diagnostic for orbital compartment syndrome. Sixty unique cases of orbital compartment syndrome were reported. Orbital compartment syndrome occurred most frequently within 24 hours post-burn. The mean total body surface area of burn was 58.7%; the mean 24-hour resuscitation volume was 6.01 cc/kg/%total burn surface area; and 86.5% of cases had periorbital burns. Surgical decompression always started with lateral canthotomy. When pressures were not immediately reduced, cantholysis was performed. Study quality per Median Newcastle Ottawa Scores ranged from 38.9% to 94.4% (median 66.7%). A precise threshold for surgical decompression of OCS remains conflicted; however, IOP>30-40mmHg warrants intervention. Burn surgeons/intensivists should be aware of the risk factors for this vision-threatening complication and act appropriately.

Deferoxamine Intradermal Delivery Patch for Treatment of a Beta-Thalassemia Wound.

MINI-ABSTRACT: In this study, we present the first-in-human use of topical deferoxamine (DFO) in the treatment of a beta-thalassemia wound. We elected to use DFO on a patient that suffered from a chronic nonhealing wound in the setting of beta-thalassemia. Despite approximately 55 weeks of marginal improvement in healing, this patient's wound healed completely after 21 weeks of treatment with DFO. We believe that DFO has the potential to accelerate healing in beta-thalassemia wounds through iron chelation.

Foot Burns and Diabetes: A Systematic Review of Current Clinical Studies and Proposal of a New Treatment Algorithm.

This study aims to systematically identify studies that evaluate lower extremity burn injury in the diabetic population, evaluate their clinical course and patient outcomes, and present a treatment algorithm tailored to diabetic burn patients. Our systematic review of the PubMed and Web of Science databases yielded 429 unique articles. After exclusion and inclusion criteria were applied, 59 articles were selected for evaluation. In diabetic patients, thermal injury was largely a result of decreased awareness and education regarding heat therapies in the context of peripheral neuropathy. All non-case studies found that metrics such as hospital length of stay, ICU admission rates, rates of comorbidity, complication rates, scald injuries, infection rates, and cost of treatment was significantly increased in the diabetic burn population as compared to their nondiabetic counterparts. Where infection was present, microorganisms colonizing diabetic burn wounds were different than those found in the burn wounds of immunocompetent individuals. Operative intervention including split-skin graft, amputation, and debridement were more often utilized in diabetic burn patients. Foot burns in diabetic patients pose unique clinical risks to patients, and as such need to be an alternate treatment protocol to reflect their pathology. Education and training programs are crucial in the prevention of diabetic foot burns to avoid complications, protracted healing, and adverse outcomes. A unique algorithm can guide the unique treatment of this clinical entity.

Allometrically scaling tissue forces drive pathological foreign-body responses to implants via Rac2-activated myeloid cells.

Small animals do not replicate the severity of the human foreign-body response (FBR) to implants. Here we show that the FBR can be driven by forces generated at the implant surface that, owing to allometric scaling, increase exponentially with body size. We found that the human FBR is mediated by immune-cell-specific RAC2 mechanotransduction signalling, independently of the chemistry and mechanical properties of the implant, and that a pathological FBR that is human-like at the molecular, cellular and tissue levels can be induced in mice via the application of human-tissue-scale forces through a vibrating silicone implant. FBRs to such elevated extrinsic forces in the mice were also mediated by the activation of Rac2 signalling in a subpopulation of mechanoresponsive myeloid cells, which could be substantially reduced via the pharmacological or genetic inhibition of Rac2. Our findings provide an explanation for the stark differences in FBRs observed in small animals and humans, and have implications for the design and safety of implantable devices.

Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing.

'Smart' bandages based on multimodal wearable devices could enable real-time physiological monitoring and active intervention to promote healing of chronic wounds. However, there has been limited development in incorporation of both sensors and stimulators for the current smart bandage technologies. Additionally, while adhesive electrodes are essential for robust signal transduction, detachment of existing adhesive dressings can lead to secondary damage to delicate wound tissues without switchable adhesion. Here we overcome these issues by developing a flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with skin-interfacing hydrogel electrodes capable of on-demand adhesion and detachment. In mice, we demonstrate that our wound care system can continuously monitor skin impedance and temperature and deliver electrical stimulation in response to the wound environment. Across preclinical wound models, the treatment group healed ~25% more rapidly and with ~50% enhancement in dermal remodeling compared with control. Further, we observed activation of proregenerative genes in monocyte and macrophage cell populations, which may enhance tissue regeneration, neovascularization and dermal recovery.

Surgical Applications of Materials Engineered with Antimicrobial Properties.

The infection of surgically placed implants is a problem that is both large in magnitude and that broadly affects nearly all surgical specialties. Implant-associated infections deleteriously affect patient quality-of-life and can lead to greater morbidity, mortality, and cost to the health care system. The impact of this problem has prompted extensive pre-clinical and clinical investigation into decreasing implant infection rates. More recently, antimicrobial approaches that modify or treat the implant directly have been of great interest. These approaches include antibacterial implant coatings (antifouling materials, antibiotics, metal ions, and antimicrobial peptides), antibacterial nanostructured implant surfaces, and antibiotic-releasing implants. This review provides a compendium of these approaches and the clinical applications and outcomes. In general, implant-specific modalities for reducing infections have been effective; however, most applications remain in the preclinical or early clinical stages.

Foot Burns in Persons With Diabetes: Outcomes From the National Trauma Data Bank.

Diabetes mellitus (DM) complicates the treatment of burn injuries. Foot burns in diabetic patients are challenging problems with unfavorable outcomes. National-scale evaluations are needed, especially with regard to limb salvage. We aim to characterize lower-extremity burns in persons with DM and evaluate the likelihood of amputation. The National Trauma Data Bank (NTDB) was queried from 2007 to 2015 extracting encounters with primary burn injuries of the feet using International Classification of Diseases (ICD) 9th edition codes. Logistic regression modeled predictors of lower-extremity amputation. Covariables included age, sex, race/ethnicity, comorbidities including DM, % burn TBSA, mechanism, and region of burn center. Poisson regression evaluated temporal incidence rate changes in DM foot burns. Of 116,796 adult burn encounters, 7963 (7%) had foot burns. Of this group, 1308 (16%) had DM. 5.6% of encounters with DM foot burns underwent amputation compared to 1.5% of non-DM encounters (P < .001). Independent predictors of lower-extremity amputation included DM (odds ratio 3.70, 95% confidence interval 2.98-4.59), alcohol use, smoking, chronic kidney disease, and burn size >20%, African-American/black race, male sex, and age >40 years (all P < .01). The incidence of DM foot burns increased over the study period with an incidence rate ratio of 1.07 (95% confidence interval 1.05-1.10, P < .001). In conclusion, DM was associated with nearly a 4-fold increase in amputation after adjusting for covariables. Furthermore, the incidence of DM foot burns is increasing. Strategies for optimizing care in persons with DM foot burns are need to improve limb salvage.

Prevalence of Ganglion Cyst Formation After Wrist Arthroscopy: A Retrospective Longitudinal Analysis of 2420 Patients.

BACKGROUND: Dorsal wrist ganglion cysts arise from the leakage of synovial fluid through tears in the scapholunate ligament and/or dorsal wrist capsule. An analogous disruption of the dorsal capsule is created with routine portal placement during wrist arthroscopy. We hypothesized that wrist arthroscopy would predispose to wrist ganglions. METHODS: Using the Truven MarketScan Outpatient Services Database from 2015 to 2016, patients who underwent wrist arthroscopy and developed an ipsilateral wrist ganglion were identified. Exclusion criteria included ganglion diagnosis preceding arthroscopy and bilateral pathology. Postoperative ganglion diagnosis was modeled with logistic regression. Predictor variables included age, gender, comorbidities, and arthroscopic procedure. RESULTS: In all, 2420 patients underwent wrist arthroscopy. Thirty (1.24%) were diagnosed with an ipsilateral wrist ganglion at a mean time of 4.0 months (standard deviation: 2.4, range: 0.2-9.0). Significant predictors of ganglion diagnosis included female gender (odds ratio [OR]: 4.0, P < .01) and triangular fibrocartilage complex and/or joint debridement (OR: 0.13, P < .01). By comparison, among all 24,718,751 outpatients who had not undergone wrist arthroscopy, 39,832 patients had a diagnosis of a wrist ganglion cyst (0.16%). CONCLUSIONS: Wrist arthroscopy is associated with a postoperative rate of ganglion cyst formation that is nearly 8 times the rate in the general population. Additional studies are needed to investigate techniques that minimize the risk of this complication.

Epistaxis After Orthognathic Surgery: Literature Review and Three Case Studies.

Study Design: This is a literature review with 3 case studies. Objective: Intraoperative and postoperative bleeding are the most common complications of orthognathic surgery and have the potential to become life-threatening. The rarity of severe postoperative epistaxis has resulted in limited characterization of these cases in the literature. The purpose of this study is to 1) differentiate various presentations of epistaxis following orthognathic surgery in the literature, 2) identify management approaches, and 3) to synthesize a treatment algorithm to guide future management of postoperative epistaxis. Methods: A literature search of PubMed was conducted and 28 cases from 17 studies were assessed. Results: Bleeding within the first week may indicate isolated epistaxis, often resolved with local tamponade. Half of cases were attributed to pseudoaneurysm rupture (n = 14), with epistaxis onset ranging from postoperative day 6 to week 9. Angiography was used in most cases (n = 17), often as the primary imaging modality (n = 11). Nasal endoscopy is a less invasive and effective alternative to angiography with embolization. Proximal vessel ligation was used in 3 cases but is not preferred because collaterals may reconstitute flow through the defect and cause rebleeding. Repeat maxillary down-fracture with surgical exploration was described in 4 cases. Conclusions: As outlined in our management algorithm, nasal packing and tamponade should be followed by either local electrocautery or vascular imaging. Angiography with embolization is the preferred approach to diagnosis and management, whereas surgical intervention is reserved for cases of embolization failure or unavailability.

Prolymphangiogenic Effects of 9-cis Retinoic Acid Are Enhanced at Sites of Lymphatic Injury and Dependent on Treatment Duration in Experimental Postsurgical Lymphedema.

Background: Patients undergoing surgical treatment for solid tumors are at risk for development of secondary lymphedema due to intraoperative lymphatic vessel injury. The damaged lymphatic vessels fail to adequately regenerate and lymphatic obstruction leads to fluid and protein accumulation in the interstitial space and chronic lymphedema develops as a result. There are currently no effective pharmacological agents that reduce the risk of developing lymphedema or treat pre-existing lymphedema, and management is largely palliative. The present study investigated the efficacy of various 9-cis retinoic acid (9-cis RA) dosing strategies in reducing postsurgical lymphedema by utilizing a well-established mouse tail lymphedema model. Methods and Results: Short-duration treatment with 9-cis RA did not demonstrate a significant reduction in postoperative tail volume, nor an improvement in lymphatic clearance. However, long-term treatment with 9-cis RA resulted in decreased overall tail volume, dermal thickness, and epidermal thickness, with an associated increase in functional lymphatic clearance and lymphatic vessel density, assessed by LYVE-1 immunostaining, compared with control. These effects were seen at the site of lymphatic injury, with no significant changes observed in uninjured sites such as ear skin and the diaphragm. Conclusions: Given the reported results indicating that 9-cis RA is a potent promoter of lymphangiogenesis and improved lymphatic clearance at sites of lymphatic injury, investigation of postoperative 9-cis RA administration to patients at high risk of developing lymphedema may demonstrate positive efficacy and reduced rates of postsurgical lymphedema.

Reinforced Biologic Mesh Reduces Postoperative Complications Compared to Biologic Mesh after Ventral Hernia Repair.

BACKGROUND: The use of biologic mesh to reinforce the abdominal wall in ventral hernia repair has been proposed as a viable alternative to synthetic mesh, particularly for high-risk patients and in contaminated settings. However, a comparison of clinical outcomes between the currently available biologic mesh types has yet to be performed. METHODS: We performed a retrospective analysis of 141 patients who had undergone ventral hernia repair with biologic mesh, including noncross-linked porcine ADM (NC-PADM) (n = 51), cross-linked porcine ADM (C-PADM) (n = 17), reinforced biologic ovine rumen (RBOR) (n = 36), and bovine ADM (BADM) (n = 37) at the Stanford University Medical Center between 2002 and 2020. Postoperative donor site complications and rates of hernia recurrence were compared between patients with different biologic mesh types. RESULTS: Abdominal complications occurred in 47.1% of patients with NC-PADM, 52.9% of patients with C-PADM, 16.7% of patients with RBOR, and 43.2% of patients with BADM (P = 0.015). Relative risk for overall complications was higher in patients who had received NC-PADM (RR = 2.64, P = 0.0182), C-PADM (RR = 3.19, P = 0.0127), and BADM (RR = 2.11, P = 0.0773) compared with those who had received RBOR. Furthermore, relative risk for hernia recurrence was also higher in all other mesh types compared with RBOR. CONCLUSION: Our data indicate that RBOR decreases abdominal complications and recurrence rates after ventral hernia repair compared with NC-PADM, C-PADM, and BADM.

Disrupting mechanotransduction decreases fibrosis and contracture in split-thickness skin grafting.

Burns and other traumatic injuries represent a substantial biomedical burden. The current standard of care for deep injuries is autologous split-thickness skin grafting (STSG), which frequently results in contractures, abnormal pigmentation, and loss of biomechanical function. Currently, there are no effective therapies that can prevent fibrosis and contracture after STSG. Here, we have developed a clinically relevant porcine model of STSG and comprehensively characterized porcine cell populations involved in healing with single-cell resolution. We identified an up-regulation of proinflammatory and mechanotransduction signaling pathways in standard STSGs. Blocking mechanotransduction with a small-molecule focal adhesion kinase (FAK) inhibitor promoted healing, reduced contracture, mitigated scar formation, restored collagen architecture, and ultimately improved graft biomechanical properties. Acute mechanotransduction blockade up-regulated myeloid CXCL10-mediated anti-inflammation with decreased CXCL14-mediated myeloid and fibroblast recruitment. At later time points, mechanical signaling shifted fibroblasts toward profibrotic differentiation fates, and disruption of mechanotransduction modulated mesenchymal fibroblast differentiation states to block those responses, instead driving fibroblasts toward proregenerative, adipogenic states similar to unwounded skin. We then confirmed these two diverging fibroblast transcriptional trajectories in human skin, human scar, and a three-dimensional organotypic model of human skin. Together, pharmacological blockade of mechanotransduction markedly improved large animal healing after STSG by promoting both early, anti-inflammatory and late, regenerative transcriptional programs, resulting in healed tissue similar to unwounded skin. FAK inhibition could therefore supplement the current standard of care for traumatic and burn injuries.