Chronic wounds-including diabetic foot ulcers, venous leg ulcers, and pressure ulcers-represent a major health problem that demands an urgent solution and new therapies. Despite major burden to patients, health care professionals, and health care systems worldwide, there are no efficacious therapies approved for treatment of chronic wounds. One of the major obstacles in achieving wound closure in patients is the lack of epithelial migration. Here, we used multiple pre-clinical wound models to show that Caveolin-1 (Cav1) impedes healing and that targeting Cav1 accelerates wound closure. We found that Cav1 expression is significantly upregulated in wound edge biopsies of patients with non-healing wounds, confirming its healing-inhibitory role. Conversely, Cav1 was absent from the migrating epithelium and is downregulated in acutely healing wounds. Specifically, Cav1 interacted with membranous glucocorticoid receptor (mbGR) and epidermal growth factor receptor (EGFR) in a glucocorticoid-dependent manner to inhibit cutaneous healing. However, pharmacological disruption of caveolae by MbCD or CRISPR/Cas9-mediated Cav1 knockdown resulted in disruption of Cav1-mbGR and Cav1-EGFR complexes and promoted epithelialization and wound healing. Our data reveal a novel mechanism of inhibition of epithelialization and wound closure, providing a rationale for pharmacological targeting of Cav1 as potential therapy for patients with non-healing chronic wounds.

Androgenetic alopecia (AGA) is a hair loss disorder affecting 80% of men and 50% of women throughout their lifetime. Therapies for AGA are limited and there is no cure. There is a high demand for hair restoration. Platelet-rich plasma (PRP), a treatment modality shown to promote wound healing, has also been explored as a treatment for AGA. This literature review wasconducted to assess the effectiveness of PRP treatment for AGA. Twelve studies conducted from 2011 to 2017 were evaluated and summarized by study characteristics, mode of preparation, and treatment protocols. A total of 295 subjects were given PRP or control treatment in these studies, and evaluated for terminal hair density, hair quality, anagen/telogen hair ratio, keratinocyte proliferation, blood vessel density, etc. Some studies also provided subject self-assessment reports. Most of the studies reviewed showed effectiveness of PRP in increasing terminal hair density/diameter. Additional investigations are needed to determine the optimal treatment regimen for high efficacy of PRP in AGA.

Perforin‐2 (P‐2) is a recently described antimicrobial protein with unique properties to kill intracellular bacteria. We investigated P‐2 expression pattern and cellular distribution in human skin and its importance in restoration of barrier function during wound healing process and infection with the common wound pathogen Staphylococcus aureus. We describe a novel approach for the measurement of P‐2 mRNA within individual skin cells using an amplified fluorescence in situ hybridization (FISH) technique. The unique aspect of this approach is simultaneous detection of P‐2 mRNA in combination with immune‐phenotyping for cell surface proteins using fluorochrome‐conjugated antibodies. We detected P‐2 transcript in both hematopoietic (CD45+) and non‐hematopoietic (CD45−) cutaneous cell populations, confirming the P‐2 expression in both professional and non‐professional phagocytes. Furthermore, we found an induction of P‐2 during wound healing. P‐2 overexpression resulted in a reduction of intracellular S. aureus, while infection of human wounds by this pathogen resulted in P‐2 suppression, revealing a novel mechanism by which S. aureus may escape cutaneous immunity to cause persistent wound infections.

The clinical field of wound healing is challenged by numerous hurdles. Not only are wound-healing disorders complex and multifactorial, but the corresponding patient population is diverse, often elderly and burdened by multiple comorbidities such as diabetes and cardiovascular disease. The care of such patients requires a dedicated, multidisciplinary team of physicians, surgeons, nurses and scientists. In spite of the critical clinical need, it has been over 15 years since a treatment received approval for efficacy by the FDA in the United States. Among the reasons contributing to this lack of effective new treatment modalities is poor understanding of mechanisms that inhibit healing in patients. Additionally, preclinical models do not fully reflect the disease complexity of the human condition, which brings us to a paradox: if we are to use a "mechanistic" approach that favours animal models, we can dissect specific mechanisms using advanced genetic, molecular and cellular technologies, with the caveat that it may not be directly applicable to patients. Traditionally, scientific review panels, for either grant funding or manuscript publication purposes, favour such "mechanistic" approaches whereby human tissue analyses, deemed "descriptive" science, are characterized as a "fishing expedition" and are considered "fatally flawed." However, more emerging evidence supports the notion that the use of human samples provides significant new knowledge regarding the molecular and cellular mechanisms that control wound healing and contribute to inhibition of the process in patients. Here, we discuss the advances, benefits and challenges of translational research in wound healing focusing on human subject research.

Pyoderma Gangrenosum (PG) is an inflammatory neutrophilic dermatosis (ND) associated with underlying chronic inflammation and/or malignancy. Diagnosis remains to be challenging as a gold standard diagnostic test is lacking. Initial manifestations may include papules, vesicles, or pustules that subsequently develop into ulceration with features of undermining and violaceous borders. Timely recognition of pyoderma gangrenosum is impeded by clinical findings shared with other etiologies, such as granulomatosis with polyangiitis, polyarteritis nodosa, and antiphospholipid syndrome. As with any other ND, extracutaneous involvement may also occur preceding, during, or following the appearance of skin lesions. Sterile neutrophilic infiltrates have been found to affect internal organs supporting the concept of PG being a systemic disease, with lung being the most common extracutaneous manifestation followed by ocular and visceral compromise. Therefore, in this review, we describe the current knowledge of extracutaneous involvement of PG and its respective clinical manifestations to aid dermatologists in diagnosis, management, and determining prognosis.