Deferoxamine topical cream superior to patch in rescuing radiation-induced fibrosis of unwounded and wounded skin.

Topical patch delivery of deferoxamine (DFO) has been studied as a treatment for this fibrotic transformation in irradiated tissue. Efficacy of a novel cream formulation of DFO was studied as a RIF therapeutic in unwounded and excisionally wounded irradiated skin. C57BL/6J mice underwent 30 Gy of radiation to the dorsum followed by 4 weeks of recovery. In a first experiment, mice were separated into six conditions: DFO 50 mg cream (D50), DFO 100 mg cream (D100), soluble DFO injections (DI), DFO 1 mg patch (DP), control cream (Vehicle), and irradiated untreated skin (IR). In a second experiment, excisional wounds were created on the irradiated dorsum of mice and then divided into four treatment groups: DFO 100 mg Cream (W-D100), DFO 1 mg patch (W-DP), control cream (W-Vehicle), and irradiated untreated wounds (W-IR). Laser Doppler perfusion scans, biomechanical testing, and histological analysis were performed. In irradiated skin, D100 improved perfusion compared to D50 or DP. Both D100 and DP enhanced dermal characteristics, including thickness, collagen density and 8-isoprostane staining compared to untreated irradiated skin. D100 outperformed DP in CD31 staining, indicating higher vascular density. Extracellular matrix features of D100 and DP resembled normal skin more closely than DI or control. In radiated excisional wounds, D100 facilitated faster wound healing and increased perfusion compared to DP. The 100 mg DFO cream formulation rescued RIF of unwounded irradiated skin and improved excisional wound healing in murine skin relative to patch delivery of DFO.

Establishing a Xenograft Model with CD-1 Nude Mice to Study Human Skin Wound Repair.

BACKGROUND: A significant gap exists in the translatability of small-animal models to human subjects. One important factor is poor laboratory models involving human tissue. Thus, the authors have created a viable postnatal human skin xenograft model using athymic mice. METHODS: Discarded human foreskins were collected following circumcision. All subcutaneous tissue was removed from these samples sterilely. Host CD-1 nude mice were then anesthetized, and dorsal skin was sterilized. A 1.2-cm-diameter, full-thickness section of dorsal skin was excised. The foreskin sample was then placed into the full-thickness defect in the host mice and sutured into place. Xenografts underwent dermal wounding using a 4-mm punch biopsy after engraftment. Xenografts were monitored for 14 days after wounding and then harvested. RESULTS: At 14 days postoperatively, all mice survived the procedure. Grossly, the xenograft wounds showed formation of a human scar at postoperative day 14. Hematoxylin and eosin and Masson trichome staining confirmed scar formation in the wounded human skin. Using a novel artificial intelligence algorithm using picrosirius red staining, scar formation was confirmed in human wounded skin compared with the unwounded skin. Histologically, CD31 + immunostaining confirmed vascularization of the xenograft. The xenograft exclusively showed human collagen type I, CD26 + , and human nuclear antigen in the human scar without any staining of these human markers in the murine skin. CONCLUSION: The proposed model demonstrates wound healing to be a local response from tissue resident human fibroblasts and allows for reproducible evaluation of human skin wound repair in a preclinical model. CLINICAL RELEVANCE STATEMENT: Radiation-induced fibrosis is a widely prevalent clinical phenomenon without a well-defined treatment at this time. This study will help establish a small-animal model to better understand and develop novel therapeutics to treat irradiated human skin.

Quality Assessment of Online Resources for Gender-affirming Surgery.

Background: As visibility of the transgender patient population and utilization of online resources increases, it is imperative that web-based gender-affirming surgery (GAS) materials for patients are readable, accessible, and of high quality. Methods: A search trends analysis was performed to determine frequency of GAS-related searches over time. The top 100 most common results for GAS-related terms were analyzed using six readability formulas. Accessibility of patient-facing GAS sources was determined by categorizing types of search results. Frequency of article types was compared in low- and high-population dense areas. Quality was assigned to GAS web-based sources using the DISCERN score. Results: Search engine trend data demonstrates increasing occurrence of searches related to GAS. Readability scores of the top 100 online sources for GAS were discovered to exceed recommended levels for patient proficiency. Availability of patient-facing online information related to GAS was found to be 60%, followed by information provided by insurance companies (17%). Differences in availability of online resources in varying dense cities were found to be minimal. The average quality of sources determined by the DISCERN score was found to be 3, indicating "potential important shortcomings." Conclusions: Despite increasing demand for web-based GAS information, the readability of online resources related to GAS was found to be significantly greater than the grade level of proficiency recommended for patients. A high number of nonpatient-facing search results appear in response to GAS search terms. Quality sources are still difficult for patients to find, as search results have a high incidence of low-quality resources.

Piezo inhibition prevents and rescues scarring by targeting the adipocyte to fibroblast transition.

While past studies have suggested that plasticity exists between dermal fibroblasts and adipocytes, it remains unknown whether fat actively contributes to fibrosis in scarring. We show that adipocytes convert to scar-forming fibroblasts in response to Piezo -mediated mechanosensing to drive wound fibrosis. We establish that mechanics alone are sufficient to drive adipocyte-to- fibroblast conversion. By leveraging clonal-lineage-tracing in combination with scRNA-seq, Visium, and CODEX, we define a "mechanically naïve" fibroblast-subpopulation that represents a transcriptionally intermediate state between adipocytes and scar-fibroblasts. Finally, we show that Piezo1 or Piezo2 -inhibition yields regenerative healing by preventing adipocytes' activation to fibroblasts, in both mouse-wounds and a novel human-xenograft-wound model. Importantly, Piezo1 -inhibition induced wound regeneration even in pre-existing established scars, a finding that suggests a role for adipocyte-to-fibroblast transition in wound remodeling, the least-understood phase of wound healing. Adipocyte-to-fibroblast transition may thus represent a therapeutic target for minimizing fibrosis via Piezo -inhibition in organs where fat contributes to fibrosis.

Topical vanadate improves tensile strength and alters collagen organisation of excisional wounds in a mouse model.

Wound dehiscence, oftentimes a result of the poor tensile strength of early healing wounds, is a significant threat to the post-operative patient, potentially causing life-threatening complications. Vanadate, a protein tyrosine phosphatase inhibitor, has been shown to alter the organisation of deposited collagen in healing wounds and significantly improve the tensile strength of incisional wounds in rats. In this study, we sought to explore the effects of locally administered vanadate on tensile strength and collagen organisation in both the early and remodelling phases of excisional wound healing in a murine model. Wild-type mice underwent stented excisional wounding on their dorsal skin and were divided equally into three treatment conditions: vanadate injection, saline injection control and an untreated control. Tensile strength testing, in vivo suction Cutometer analysis, gross wound measurements and histologic analysis were performed during healing, immediately upon wound closure, and after 4 weeks of remodelling. We found that vanadate treatment significantly increased the tensile strength of wounds and their stiffness relative to control wounds, both immediately upon healing and into the remodelling phase. Histologic analysis revealed that these biomechanical changes were likely the result of increased collagen deposition and an altered collagen organisation composed of thicker and distinctly organised collagen bundles. Given the risk that dehiscence poses to all operative patients, vanadate presents an interesting therapeutic avenue to improve the strength of post-operative wounds and unstable chronic wounds to reduce the risk of dehiscence.

Adipose-Derived Stromal Cell-Based Therapies for Radiation-Induced Fibrosis.

Significance: Half of all cancer patients receive radiation therapy as a component of their treatment regimen, and the most common resulting complication is radiation-induced fibrosis (RIF) of the skin and soft tissue. This thickening of the dermis paired with decreased vascularity results in functional limitations and esthetic concerns and poses unique challenges when considering surgical exploration or reconstruction. Existing therapeutic options for RIF of the skin are limited both in scope and efficacy. Cell-based therapies have emerged as a promising means of utilizing regenerative cell populations to improve both functional and esthetic outcomes, and even as prophylaxis for RIF. Recent Advances: As one of the leading areas of cell-based therapy research, adipose-derived stromal cells (ADSCs) demonstrate significant therapeutic potential in the treatment of RIF. The introduction of the ADSC-augmented fat graft has shown clinical utility. Recent research dedicated to characterizing specific ADSC subpopulations points toward further granularity in understanding of the mechanisms driving the well-established clinical outcomes seen with fat grafting therapy. Critical Issues: Various animal models of RIF demonstrated improved clinical outcomes following treatment with cell-based therapies, but the cellular and molecular basis underlying these effects remains poorly understood. Future Directions: Recent literature has focused on improving the efficacy of cell-based therapies, most notably through (1) augmentation of fat grafts with platelet-rich plasma and (2) the modification of expressed RNA through epitranscriptomics. For the latter, new and promising gene targets continue to be identified which have the potential to reverse the effects of fibrosis by increasing angiogenesis, decreasing inflammation, and promoting adipogenesis.

Transdermal deferoxamine administration improves excisional wound healing in chronically irradiated murine skin.

BACKGROUND: Radiation-induced skin injury is a well-known risk factor for impaired wound healing. Over time, the deleterious effects of radiation on skin produce a fibrotic, hypovascular dermis poorly suited to wound healing. Despite increasing understanding of the underlying pathophysiology, therapeutic options remain elusive. Deferoxamine (DFO), an iron-chelating drug, has been shown in prior murine studies to ameliorate radiation-induced skin injury as well as improve wound healing outcomes in various pathologic conditions when administered transdermally. In this preclinical study, we evaluated the effects of deferoxamine on wound healing outcomes in chronically irradiated murine skin. METHODS: Wild-type mice received 30 Gy of irradiation to their dorsal skin and were left to develop chronic fibrosis. Stented excisional wounds were created on their dorsal skin. Wound healing outcomes were compared across 4 experimental conditions: DFO patch treatment, vehicle-only patch treatment, untreated irradiated wound, and untreated nonirradiated wounds. Gross closure rate, wound perfusion, scar elasticity, histology, and nitric oxide assays were compared across the conditions. RESULTS: Relative to vehicle and untreated irradiated wounds, DFO accelerated wound closure and reduced the frequency of healing failure in irradiated wounds. DFO augmented wound perfusion throughout healing and upregulated angiogenesis to levels observed in nonirradiated wounds. Histology revealed DFO increased wound thickness, collagen density, and improved collagen fiber organization to more closely resemble nonirradiated wounds, likely contributing to the observed improved scar elasticity. Lastly, DFO upregulated inducible nitric oxide synthase and increased nitric oxide production in early healing wounds. CONCLUSION: Deferoxamine treatment presents a potential therapeutic avenue through which to target impaired wound healing in patients following radiotherapy.

Tension offloading improves cutaneous scar formation in Achilles tendon repair.

Hypertrophic scar formation and non-healing wounds following Achilles tendon repair arise from poor vascularity to the incisional site or from excess mechanical stress/strain to the incision during the healing process. The embrace® scar therapy dressing is a tension offloading device for incisional scars. This study explored the effects of tension offloading during Achilles scar formation. A healthy 30-year-old male without any medical co-morbidities developed an acute rupture of his left Achilles tendon. The patient underwent open repair 1 week after injury. At post-operative day (POD) 14, the patient started daily tension offloading treatment on the inferior portion of the incision through POD 120. By POD 120, the untreated portion of the Achilles incision appeared hypertrophic and hyperpigmented, while the treated portion of the scar appeared flat with minimal pigmentation changes. The 12-week treatment of tension offloading on an Achilles tendon repair incision significantly improved cosmesis compared to untreated incision.

Fat Grafts Augmented With Vitamin E Improve Volume Retention and Radiation-Induced Fibrosis.

BACKGROUND: Treatments for radiation-induced fibrosis range from vitamin E (VE) and pentoxifylline (PTX) systemically to deferoxamine and fat grafting locally. Regarding fat grafting, volume retention hinders its long-term functionality and is affected by 2 factors: inflammation and necrosis secondary to hypovascularity. OBJECTIVE: The authors aimed to simultaneously improve fat graft retention and radiation-induced fibrosis by integrating VE and PTX into fat grafts locally. METHODS: Forty adult CD-1 nude male mice, 6 weeks old, underwent scalp irradiation and recovered for 4 weeks to allow for development of fibrosis. Mice received 200 µL of donor human fat graft to the scalp. Mice were separated into 4 conditions: no grafting, fat graft without treatment, graft treated with PTX, and graft treated with VE. Fat graft volume retention was monitored in vivo with micro-computed tomography scans at weeks 0, 1, 2, 4, 6, and 8 after grafting. Histological and cytokine analysis of the scalp skin and fat grafts were performed. RESULTS: VE-treated grafts had significant improvement in dermal thickness and collagen density of overlying skin compared with all other groups. VE decreased 8-isoprostane and increased CD31+ staining compared with the other grafted groups. Cytokine analysis revealed decreased inflammatory and increased angiogenic markers in both the fat graft and overlying skin of the VE group. Fat graft volume retention was significantly improved in the VE group starting at 1 week post grafting. CONCLUSIONS: Radiation-induced fibrosis and fat graft volume retention are both simultaneously improved with local administration of VE.