L-4-thiazolylalanine (Protinol), a novel non-proteinogenic amino acid, demonstrates epidermal and dermal efficacy with clinically observable benefits.

OBJECTIVE: Facial skin undergoes major structural and functional changes as a result of intrinsic and extrinsic factors. The goal of the current work is to demonstrate L-4-thiazolylalaine (L4, Protinol), a non-proteinogenic amino acid shown to stimulate the production of dermal proteins by fibroblasts, is an alternative efficacious topical ingredient for visible signs of ageing. METHODS: In vitro studies using 3D human skin tissue models were performed to show changes in protein and gene expression of key dermal markers in samples treated with 0.3% L4 compared to vehicle control. In vivo evaluation of skin turnover was measured in volunteers after treatment with L4 compared to retinol. Skin biopsies (n = 30) were taken to investigate epidermal and dermal changes in cases treated with L4 and compared to retinol. Finally, a clinical evaluation (n = 28) was conducted to assess the efficacy of L4 over a base formulation using various ageing parameters within a population of women 46-66 years old with mild-to-moderate wrinkles. RESULTS: In vitro studies on 3D tissues displayed significant changes in the dermal matrix via an increase in HA and pro-collagen I production and a decrease in the expression of inflammatory genes. In vivo biopsy studies demonstrated that L4 and retinol independently increased epidermal thickness and collagen remodelling significantly more compared with the base formula. Clinical evaluation showed firmer and smoother skin at day 28 post-treatment with L4 over the vehicle control without causing side effects such as redness or irritation. CONCLUSION: L4 is a novel, multi-functional ingredient which offers a superior alternative to currently available technologies for improving epidermal and dermal parameters that change during ageing and photodamage.

OBJECTIF: La peau du visage est sujet à des changements majeurs structuraux et fonctionnels dus à des facteurs intrinsèques et extrinsèques. Dans cette étude, nous montrons que l'acide aminé non-protéinogène L-4-thiazolylalanine (L4, Protinol) est une alternative intéressante pour une application topique. MÉTHODES: Des modèles 3D de peaux ont été utilisés pour mesurer les changements d'expressions géniques et protéiques de marqueurs clés du derme à partir d'échantillons traités avec L4 comparés à une condition contrôle. In vivo, après un traitement L4, le renouvellement cutané a été mesuré chez les volontaires et comparé à un traitement au rétinol. Des biopsies de peaux (n = 30) traitées soit à L4 soit au rétinol ont été isolées afin d'évaluer les changements au niveau du derme et de l'épiderme. Pour finir, une étude clinique (n = 28) a été menée pour évaluer l'efficacité de L4 par rapport à une formulation de base en utilisant différents paramètres de vieillissement au sein d'une population de femmes de 46 à 66 ans présentant des rides légères à modérées. RÉSULTATS: Les études in vitro sur tissues 3D ont montré des changements dans la matrice du derme avec une augmentation de la production d'acide hyaluronique et de procollagène I et une diminution d'expression de gènes pro-inflammatoires. Les études menées in vivo sur biopsies ont démontré que L4 et rétinol augmentaient indépendamment tous deux significativement l'épaisseur de l'épiderme et le remodelage du collagène par rapport à leur base seule. Pour finir, une peau plus ferme et plus lisse a été mesurée cliniquement après 28 jours de traitement L4 par rapport au véhicule et cela sans effets indésirables tels que rougeur et irritation. CONCLUSION: L4 est un ingrédient, innovant et multifonctionnel. Il offre une sérieuse alternative aux technologies actuellement disponibles dans les traitements contre le vieillissement de la peau ou le photodommage.

Immune cells and associated molecular markers in dermal fibrosis with focus on raised cutaneous scars.

Raised dermal scars including hypertrophic, and keloid scars as well as scalp-associated fibrosing Folliculitis Keloidalis Nuchae (FKN) are a group of fibrotic raised dermal lesions that mostly occur following cutaneous injury. They are characterized by increased extracellular matrix (ECM) deposition, primarily excessive collagen type 1 production by hyperproliferative fibroblasts. The extent of ECM deposition is thought to be proportional to the severity of local skin inflammation leading to excessive fibrosis of the dermis. Due to a lack of suitable study models, therapy for raised dermal scars remains ill-defined. Immune cells and their associated markers have been strongly associated with dermal fibrosis. Therefore, modulation of the immune system and use of anti-inflammatory cytokines are of potential interest in the management of dermal fibrosis. In this review, we will discuss the importance of immune factors in the pathogenesis of raised dermal scarring. The aim here is to provide an up-to-date comprehensive review of the literature, from PubMed, Scopus, and other relevant search engines in order to describe the known immunological factors associated with raised dermal scarring. The importance of immune cells including mast cells, macrophages, lymphocytes, and relevant molecules such as cytokines, chemokines, and growth factors, antibodies, transcription factors, and other immune-associated molecules as well as tissue lymphoid aggregates identified within raised dermal scars will be presented. A growing body of evidence points to a shift from proinflammatory Th1 response to regulatory/anti-inflammatory Th2 response being associated with the development of fibrogenesis in raised dermal scarring. In summary, a better understanding of immune cells and associated molecular markers in dermal fibrosis will likely enable future development of potential immune-modulated therapeutic, diagnostic, and theranostic targets in raised dermal scarring.

Energy-based devices for the treatment of Acne Scars: 2022 International consensus recommendations.

BACKGROUND AND OBJECTIVES: Acne scars are one of the most distressing and long-term consequences of acne vulgaris, with damaging effect on a person's physical, mental, and social well-being. Numerous treatment options are available including surgical and nonsurgical techniques, depending on the clinical presentation. Although considerable advances in the development of new treatment technologies and applications have been made in the last decade, international treatment guidelines and reimbursement schemes have not yet caught up with current knowledge and practice in many centers. The authors intend to highlight the potential utility of energy-based devices (EBDs) for acne scarring, offer recommendations for safe and efficacious treatment, and provide consensus-based EBD treatment options based on varying presentations demonstrated in a series of real-life clinical photographs. STUDY DESIGN/MATERIALS AND METHODS: An international panel of 24 dermatologists and plastic surgeons from 12 different countries and a variety of practice backgrounds was self-assembled to develop updated consensus recommendations for the treatment of acne scars. A two-step modified Delphi method took place between March 2020 and February 2021 consisting of two rounds of emailed questionnaires. The panel members approved the final manuscript via email correspondence. RESULTS: The manuscript includes a comprehensive discussion and panel recommendations regarding the following topics: 1. the role of EBD in mitigating and treating acne scars in a patient with active acne, 2. the use of various EBDs for the treatment of different acne scar types with special focus on commonly used laser platform such as vascular lasers, ablative fractional lasers (AFLs) and non-AFLs (NAFLs), 3. treatment combinations, and 4. acne scar treatments in skin of color. The last part comprised of 10 photos of real-life clinical cases with the panel recommendation treatment plan to achieve best aesthetic outcome. CONCLUSION: Panel members were unanimous in their view that EBDs have a role in the management of acne scars, with AFLs, NAFLs, vascular lasers, and RF devices preferentially selected by most of the panel experts. EBDs are considered a first-line treatment for a variety of acne scar types and patients without access to these treatments may not be receiving the best available care for optimal cosmetic results. Future high-quality research and updated international treatment guidelines and reimbursement schemes should reflect this status.

Keloid scarring or disease: Unresolved quasi-neoplastic tendencies in the human skin.

Keloids are benign fibroproliferative dermal scars of unknown etiopathogenesis resulting in an exophytic protuberant growth with persistent and progressive peri-lesional expansile behavior. Keloids are likened to benign neoplastic lesions due to their aggressive clinical behavior, genotypic-phenotypic tissue characteristics, and resistance to treatment. Keloids are traditionally viewed as scars on the healing spectrum; however, keloids are a distinct pathology provoked by cutaneous injury rather than a continuum. In order to elucidate the etiopathogenesis of keloids, the distinction between scar and disease must be made. Therefore, we hypothesize that the link between keloids and their quasi-neoplastic tendencies distinguish it as a disease rather than a scar alone. The biomarker expression profile in these diseases highlight the striking parallels between keloids and both benign and malignant mesenchymal tumors. Signaling pathways common to these diseases have been found to guide the matrix composition of keloids. This hypothesis underscores the need to identify keloids not as a scar but as a disease in order to develop targeted therapy, which can lead to enhanced diagnosis and theranosis.

Laser Treatment of Traumatic Scars and Contractures: 2020 International Consensus Recommendations.

BACKGROUND AND OBJECTIVES: There is currently intense multidisciplinary interest and a maturing body of literature regarding laser treatments for traumatic scars, but international treatment guidelines and reimbursement schemes have not yet caught up with current knowledge and practice in many centers. The authors intend to highlight the tremendous potential of laser techniques, offer recommendations for safe and efficacious treatment, and promote wider patient access guided by future high-quality research. STUDY DESIGN/MATERIALS AND METHODS: An international panel of 26 dermatologists and plastic and reconstructive surgeons from 13 different countries and a variety of practice backgrounds was self-assembled to develop updated consensus recommendations for the laser treatment of traumatic scars. A three-step modified Delphi method took place between March 2018 and March 2019 consisting of two rounds of emailed questionnaires and supplementary face-to-face meetings. The panel members approved the final manuscript via email correspondence, and the threshold for consensus was at least 80% concurrence among the panel members. RESULTS: The manuscript includes extensive detailed discussion regarding a variety of laser platforms commonly used for traumatic scar management such as vascular lasers and ablative and non-ablative fractional lasers, special considerations such as coding and laser treatments in skin of color, and 25 summary consensus recommendations. CONCLUSIONS: Lasers are a first-line therapy in the management of traumatic scars and contractures, and patients without access to these treatments may not be receiving the best available care after injury. Updated international treatment guidelines and reimbursement schemes, additional high-quality research, and patient access should reflect this status. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

A Review of the Evidence for and against a Role for Mast Cells in Cutaneous Scarring and Fibrosis.

Scars are generated in mature skin as a result of the normal repair process, but the replacement of normal tissue with scar tissue can lead to biomechanical and functional deficiencies in the skin as well as psychological and social issues for patients that negatively affect quality of life. Abnormal scars, such as hypertrophic scars and keloids, and cutaneous fibrosis that develops in diseases such as systemic sclerosis and graft-versus-host disease can be even more challenging for patients. There is a large body of literature suggesting that inflammation promotes the deposition of scar tissue by fibroblasts. Mast cells represent one inflammatory cell type in particular that has been implicated in skin scarring and fibrosis. Most published studies in this area support a pro-fibrotic role for mast cells in the skin, as many mast cell-derived mediators stimulate fibroblast activity and studies generally indicate higher numbers of mast cells and/or mast cell activation in scars and fibrotic skin. However, some studies in mast cell-deficient mice have suggested that these cells may not play a critical role in cutaneous scarring/fibrosis. Here, we will review the data for and against mast cells as key regulators of skin fibrosis and discuss scientific gaps in the field.

Multi-dimensional models for functional testing of keloid scars: In silico, in vitro, organoid, organotypic, ex vivo organ culture, and in vivo models.

Keloid scars are described as benign fibro-proliferative dermal outgrowths that commonly occur in pigmented skin post cutaneous injury, and continue to grow beyond the boundary of the original wound margin. There is a lack of thorough understanding of keloid pathogenesis and thus keloid therapeutic options remain ill-defined. In view of the poor response to current therapy and high recurrence rates, there is an unmet need in improving our knowledge and therefore in identifying targeted and effective treatment strategies in management of keloids. Keloid research however, is hampered by a lack of relevant animal models as keloids do not spontaneously occur in animals and are unique to human skin. Therefore, developing novel animal models and nonanimal models for functional evaluation of keloid cells and tissue for better understanding their pathobiology and response to putative candidate therapies are essential. Here, we present the key concepts and relevant emerging research on two-dimensional and three-dimensional cell and tissue models for functional testing of keloid scars. We will describe in detail current models including in vitro mono- and co-cultures, multi-cellular spheroids (organoids) and organotyopic cultures, ex vivo whole skin keloid tissue organ culture models as well as in vivo human patient models. Finally, we discuss the role played by time as the fourth dimension in a novel model that involves sequential temporal biopsies of human patients with keloids (a so called 4D in vivo human model). The use of these unique models will no doubt prove pivotal in identification of new drug targets as well as biomarkers, in functional testing of emerging novel therapeutics, and in enhancing our understanding of keloid disease biology.

Electrical stimulation disrupts biofilms in a human wound model and reveals the potential for monitoring treatment response with volatile biomarkers.

Management of biofilm infections relies on time-consuming laboratory techniques and monitoring treatment by subjective clinical evaluations. Due to these limitations, there is a need to explore alternative strategies. The aims of this study were to assess the feasibility of using volatile organic compound (VOC) biomarkers to monitor treatment response and measure anti-biofilm efficacy of electrical stimulation (ES) in vitro and in human cutaneous wound biofilm models. Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (PA) biofilms were exposed to ES, ciprofloxacin, or both, with efficacy assessed and quantified by fluorescence staining, enumeration, metabolic assays, and biomass quantification; VOCs were measured by gas chromatography-mass spectrometry. In vitro MSSA and PA and ex vivo PA biofilms exposed to ES showed significantly reduced bacterial viability, metabolic activity, and biomass compared to controls (p < 0.05). There was significant variation in the relative abundance of VOCs in in vitro MSSA and PA and in ex vivo PA biofilms exposed to ES and antibiotic (p < 0.05). 2-methyl-1-propanol was associated with MSSA viability (R = 0.93, p < 0.05), biomass (R = 0.97, p < 0.05), and metabolic activity (R = 0.93, p < 0.05) and 3-methyl-1-butanol was associated with PA biomass (R = 0.93, p < 0.05). We showed that ES and VOC biomarkers are possible options for alternative nonpharmacological antimicrobial management of biofilms and noninvasive monitoring of wound infection treatment responses, respectively.

Novel Proteomic Assay of Breast Implants Reveals Proteins With Significant Binding Differences: Implications for Surface Coating and Biocompatibility.

BACKGROUND: Silicone elastomer, a ubiquitous biomaterial and main constituent of breast implants, has been used for breast augmentation and reconstruction for over 50 years. Breast implants have direct local and purported systemic effects on normal tissue homeostasis dictated by the chemical and physical presence of the implant. OBJECTIVES: Protein adsorption has been demonstrated to be a key driver of local reactions to silicone. We sought to develop an assay and identify the proteins that coat implants during breast implantation. METHODS: Wound fluid was salvaged from women who had undergone breast reduction and incubated in contact with the surface of 13 commercially available implant surfaces. An in situ digestion technique was optimized to elute bound proteins. Samples were analyzed on an Orbitrap elite analyser, proteins identified in Mascot Demon and analyzed in Progenesis. RESULTS: A total of 822 proteins were identified, bound to the surfaces of the implants. Extracellular proteins were the most abundant ontology, followed by intracellular proteins. Fibrinogen, a proinflammatory protein and Albumin, an anti-inflammatory protein had significant (P < 0.0001) binding differences between the surfaces studied. Complement C3, C5, and factor H were also shown to have significantly different binding affinities for the implants included in the study (P < 0.05). CONCLUSIONS: We have developed a novel assay of breast implant protein binding and demonstrated significant binding affinities for relevant proteins derived from breast tissue wound fluid.

The efficacy of electrical stimulation in lower extremity cutaneous wound healing: A systematic review.

Current gold standard lower extremity cutaneous wound management is not always effective. Cutaneous wounds generate a "current of injury" which is directly involved in wound healing processes. Application of exogenous electrical stimulation has been hypothesised to imitate the natural electric current that occurs in cutaneous wounds. The aim of this extensive review was to provide a detailed update on the variety of electrical stimulation modalities used in the management of lower extremity wounds. Several different waveforms and delivery methods of electrical stimulation have been used. Pulsed current appears superior to other electrical modalities available. The majority of studies support the beneficial effects of pulsed current over conservative management of lower extremity cutaneous wounds. Although it appears to have no benefit over causal surgical intervention, it is a treatment option which could be utilised in those patients unsuitable for surgery. Other waveforms and modalities appear promising; however, they still lack large trial data to recommend a firm conclusion with regards to their use. Current studies also vary in quantity, quality and protocol across the different modalities. The ideal electrical stimulation device needs to be non-invasive, portable and cost-effective and provides minimal interference with patients' daily life. Further studies are necessary to establish the ideal electrical stimulation modality, parameters, method of delivery and duration of treatment. The development and implementation of newer devices in the management of acute and chronic wounds provides an exciting direction in the field of electrotherapy.

Non-animal models of wound healing in cutaneous repair: In silico, in vitro, ex vivo, and in vivo models of wounds and scars in human skin.

Tissue repair models are essential to explore the pathogenesis of wound healing and scar formation, identify new drug targets/biomarkers and to test new therapeutics. However, no animal model is an exact replicate of the clinical situation in man as in addition to differences in the healing of animal skin; the response to novel therapeutics can be variable when compared to human skin. The aim of this review is to evaluate currently available non-animal wound repair models in human skin, including: in silico, in vitro, ex vivo, and in vivo. The appropriate use of these models is extremely relevant to wound-healing research as it enables improved understanding of the basic mechanisms present in the wound healing cascade and aid in discovering better means to regulate them for enhanced healing or prevention of abnormal scarring. The advantage of in silico models is that they can be used as a first in virtue screening tool to predict the effect of a drug/stimulus on cells/tissues and help plan experimental research/clinical trial studies but remain theoretical until validated. In vitro models allow direct quantitative examination of an effect on specific cell types alone without incorporating other tissue-matrix components, which limits their utility. Ex vivo models enable immediate and short-term evaluation of a particular effect on cells and its surrounding tissue components compared with in vivo models that provide direct analysis of a stimulus in the living human subject before/during/after exposure to a stimulus. Despite clear advantages, there remains a lack of standardisation in design, evaluation and follow-up, for acute/chronic wounds and scars in all models. In conclusion, ideal models of wound healing research are desirable and should mimic not only the structure but also the cellular and molecular interactions, of wound types in human skin. Future models may also include organ/skin-on-a-chip with potential application in wound healing research.

Volatile organic compound detection as a potential means of diagnosing cutaneous wound infections.

Chronic cutaneous wound infections and surgical site infections (SSIs) present a huge burden on the healthcare system and can lead to increased morbidity and mortality. Current diagnostic methods of identifying and confirming infection involve culture-based and molecular methods. Both techniques are time-consuming and delays commonly lead to untargeted empirical treatment. An ideal diagnostic method would be noninvasive and highly sensitive and detect pathogenic organisms with a high degree of accuracy to allow targeted treatment. Volatile organic compounds (VOCs) are a diverse group of carbon-based molecules produced and released by humans and microorganisms. VOC detection has the potential in aiding cutaneous wound infection diagnostics using noninvasive and time-efficient methods. This review provides a comprehensive update on VOCs produced and emitted by bacteria commonly associated with chronic wounds and SSIs. VOC sampling has the advantage of being painless, time-efficient, noninvasive, and reproducible. VOCs emitted by these organisms are diverse. In vitro studies have identified potential signature volatile profiles, which can be used in detecting these microorganisms. Combining these profiles with volatile profiles emitted from acute, chronic and surgical wounds in vivo could potentially allow identification of bacterial-specific VOCs. VOC detection has the potential for a relatively inexpensive, portable, noninvasive, and reliable clinical diagnostic tool, which could be used in detecting cutaneous wound infections and guiding their optimal management.

Therapeutic targets in the management of striae distensae: A systematic review.

BACKGROUND: Striae distensae are permanent dermal lesions that can cause significant psychosocial distress. A detailed understanding of the numerous treatment modalities available is essential to ensuring optimal patient outcomes. OBJECTIVE: Our objective was to evaluate and summarize the different treatment methods for striae distensae by linking their proposed modes of action with the histopathogenesis of the condition to guide patient treatment. METHODS: A systematic review of the literature was performed with no limits placed on publication date. Relevant studies were assigned a level of evidence by the authors. RESULTS: Ninety-two articles were identified, with 74 being eligible for quality assessment. The majority of treatments aim to increase collagen production. The use of vascular lasers can reduce erythema in striae rubrae by targeting hemoglobin, whereas increasing melanin through methods such as ultraviolet light is a major focus for treatment of striae albae. Despite some topical treatments being widely used, uncertainty regarding their mode of action remains. No treatment has proved to be completely effective. LIMITATIONS: Limitations of the study include low-quality evidence, small sample sizes, and varying treatment protocols and outcome measures, along with concerns regarding publication bias. CONCLUSIONS: Further randomized, controlled trials are needed before definitive conclusions and recommendations can be made.

A Role for Neuregulin-1 in Promoting Keloid Fibroblast Migration via ErbB2-mediated Signaling.

Keloid disease is a fibroproliferative tumour characterised by aggressive local invasion, evident from a clinically and histologically active migrating margin. During combined laser capture microdissection and microarray analysis-based in situ gene expression profiling, we identified upregulation of the polypeptide growth factor neuregulin-1 (NRG1) and ErbB2 oncogene in keloid margin dermis, leading to the hypothesis that NRG1 contributed to keloid margin migration through ErbB2-mediated signalling. The aim of this study was to probe this hypothesis through functional in vitro studies. Exogenous NRG1 addition to keloid and normal skin fibroblasts altered cytokine expression profiles, significantly increased in vitro migration and keloid fibroblast Src and protein tyrosine kinase 2 (PTK2/FAK) gene expression. ErbB2 siRNA knockdown attenuated both keloid fibroblast migration and Src/PTK2 expression, which were not recovered following NRG1 administration, suggesting the NRG1/ErbB2/Src/PTK2 signaling pathway may be a novel regulator of keloid fibroblast migration, and representing a potential new therapeutic target.

Transforming Growth Factor Beta Gene Signatures are Spatially Enriched in Keloid Tissue Biopsies and Ex vivo-Cultured Keloid Fibroblasts.

The keloid lesion is recognised as a spatially heterogeneous mass both in cellular and acellular composition and biological activity. Here, we have utilised a bioinformatic approach to determine whether this spatial heterogeneity is also evident at the molecular level and to identify key upstream regulators of signalling pathways enriched in the lesion in a spatially-restricted manner. Differentially expressed genes (20% change, p < 0.05) obtained from microarray datasets derived from whole keloid biopsies and ex vivo-cultured keloid fibroblasts, both from distinct regions of the keloid lesion (leading edge, centre, and top) have been analysed to show that the TGFß family plays a significant but spatially dependent role in regulation of keloid gene expression. Furthermore, we have identified additional upstream signalling molecules involved in driving keloid biology and provide information on therapeutic targets whose modulation might be expected to lead to significant therapeutic efficacy.

Non-invasive objective devices for monitoring the inflammatory, proliferative and remodelling phases of cutaneous wound healing and skin scarring.

Objective evaluation of cutaneous wounds through the use of non-invasive devices is important for diagnosis, monitoring treatment response and can lead to the development of improved theranostic strategies. The need for objective monitoring of wound healing and scar formation is evident as this enables accurate diagnosis, evaluation and prognosis for clinicians and allows for the standardisation and validation of methodology for researchers. Therefore, this review provides an overview of the current application of non-invasive objective technologies for the assessment of wound healing through the different phases of repair. We propose that cutaneous healing parameters can be split into three core domains: anatomical, mechanical and physiological. These categories can be further subdivided with respect to specific phases of healing. There is no single instrument, which can measure all the parameters of healing simultaneously; thus, it is important to choose the correct device for the particular healing characteristics being monitored. However, multiprobe systems, which include a number of devices connected to one main unit, are useful as they enable multiple measurements of different parameters. Many of the devices have not been validated against histological examination. Additionally, some of the instruments have not been evaluated in all wound or scar types and may not be useful throughout all phases of cutaneous wound healing. In conclusion, non-invasive objective devices are useful in the assessment of cutaneous wound healing, as these tools can link the treatment and diagnosis by evaluating response to treatment and thus could aid as a marker for healing and scar maturation.

Whole genome microarray data of chronic wound debridement prior to application of dermal skin substitutes.

Clinical consensus is that debridement is necessary for successful application of dermal skin substitutes (DSS) to chronic wounds. The aim here was to identify commonly expressed genes associated with wound healing in untreated acute wounds and chronic wounds treated with wound debridement followed by DSS. Cutaneous biopsies were taken at two time points from untreated acute and chronic wounds and from chronic wounds treated with DSS following debridement. Microarray analysis identified significant differences (p < 0.05) related to proliferation (HIPK2, LGR4, FGFR1, SRRT), migration (RHOC, PRPF40A, FGFR1), differentiation (TCF4, COL13A1, GNPTAB, HUWE1, FGFR1), angiogenesis (HIPK2, CASP8), extracellular matrix organization (VWA1), and apoptosis (BBC3, HIPK2, KLF11, PSME3, MSFD10, TOP2A, MLH1, CASP8, PDIA3, XAF1) when comparing untreated chronic wounds to chronic wounds treated with DSS, with similar expression levels compared to untreated acute wounds. Chronic wounds treated with debridement followed by DSS resemble untreated acute wounds at a genomic level. These novel findings, albeit with limited clinical specimen numbers, strengthen the recommendation to transform chronic into acute wounds prior to application of DSS.

The Role of Neuromediators and Innervation in Cutaneous Wound Healing.

The skin is densely innervated with an intricate network of cutaneous nerves, neuromediators and specific receptors which influence a variety of physiological and disease processes. There is emerging evidence that cutaneous innervation may play an important role in mediating wound healing. This review aims to comprehensively examine the evidence that signifies the role of innervation during the overlapping stages of cutaneous wound healing. Numerous neuropeptides that are secreted by the sensory and autonomic nerve fibres play an essential part during the distinct phases of wound healing. Delayed wound healing in diabetes and fetal cutaneous regeneration following wounding further highlights the pivotal role skin innervation and its associated neuromediators play in wound healing. Understanding the mechanisms via which cutaneous innervation modulates wound healing in both the adult and fetus will provide opportunities to develop therapeutic devices which could manipulate skin innervation to aid wound healing.

The efficacy of electrical stimulation in experimentally induced cutaneous wounds in animals.

BACKGROUND: Complicated cutaneous wounds and their subsequent management can be a clinical challenge in veterinary medicine. There is still an unmet need for an ideal wound healing therapy that is able to stimulate efficiency and quality of repair. Skin wounds generate large and persistent endogenous electric currents and fields termed the "current of injury". The current of injury is involved in numerous processes of wound healing. These observations have led to the hypothesis that applied electrical stimulation (ES) may promote wound healing by imitating the natural electrical current that occurs in cutaneous wounds. OBJECTIVES: This review details the use, effect and mechanism of ES in different preclinical experimental cutaneous wound models and discusses the potential of how ES could be translated into veterinary practice. RESULTS: Studies have found a variable effect of ES on wound healing. Some have been positive with faster rates of wound re-epithelialization, increased wound collagen formation and angiogenesis noted. Other studies have shown no effect or detrimental results. The effects of ES are highly influenced by the ES modality, polarity and parameters. CONCLUSIONS AND CLINICAL IMPORTANCE: Electrical stimulation has the potential to play a significant role in enhancing cutaneous wound healing in veterinary practice. Clinical studies are necessary to corroborate the findings from experimental studies which have shown promise including the use of alternating pulsed and direct current and the use of bio-electric dressings. The ideal ES device would need to be safe, easy to use, portable, noninvasive and aid wound healing by having a beneficial effect on all wound healing stages.

Optimization of an ex vivo wound healing model in the adult human skin: Functional evaluation using photodynamic therapy.

Limited utility of in vitro tests and animal models of human repair, create a demand for alternative models of cutaneous healing capable of functional testing. The adult human skin Wound Healing Organ Culture (WHOC) provides a useful model, to study repair and enable evaluation of therapies such as the photodynamic therapy (PDT). Thus, the aim here was to identify the optimal WHOC model and to evaluate the role of PDT in repair. Wound geometry, system of support, and growth media, cellular and matrix biomarkers were investigated in WHOC models. Subsequently, cellular activity, extracellular matrix remodeling, and oxidative stress plus gene and protein levels of makers of wound repair measured the effect of PDT on the optimized WHOC. WHOCs embedded in collagen and supplemented DMEM were better organized showing stratified epidermis and compact dermis with developing neo-epidermis. Post-PDT, the advancing reepithelialization tongue was 3.5 folds longer, and was highly proliferative with CK-14 plus p16 increased (p < 0.05) compared to controls. The neo-epidermis was fully differentiated forming neo-collagen. Proliferating nuclear antigen, p16, COLI, COLIII, MMP3, MMP19, and α-SMA were significantly more expressed (p < 0.05) in dermis surrounding the healing wound. In conclusion, an optimal model of WHOC treated with PDT shows increased reepithelialization and extracellular matrix reconstruction and remodeling, supporting evidence toward development of an optimal ex vivo wound healing model.