Homeostasis of the epidermal barrier layer: A theory of how occlusion reduces hypertrophic scarring

A randomised investigation of film-forming silicone gel in superficial partial thickness face and neck burn patients: Indication of improved early scar pigmentation outcomes

INTRODUCTION

Burns to the face and neck are a source of considerable distress and a challenge to manage with dressings. Further, these often superficial injuries pose a risk of scarring and altered pigmentation. Silicone gels have emerged as a potential solution to the challenges of conservative management for face and neck burn injuries. The aims of this study were to explore the effect of topical silicone compared to routine treatment of conservatively managed burns to the face and neck.

METHODS

This single-blind, randomised, controlled trial compared topical silicone film-forming dressing to standard of care for superficial partial thickness burns to the face and neck. Time to healing was the primary outcome and secondary outcomes included: 1) scar assessments (modified Vancouver Scar Scale, Dermalab Combo and Patient and Observer Scar Assessment Scale) at six weeks and three months; and 2) pain intensity scale at wound review appointments.

RESULTS

Of the 55 participants in the face/neck study, 34 were male and 21 were female. Median age was 36 years (range from 25 to 47 years). The median time to healing for the silicone group was 9 days (CI 7.6 -10.4) and the control group was 7 days (CI 5.3- 8.7), p = 0.056. Analysis demonstrated significantly reduced pigmentation at six weeks in mVSS scores for the silicone group (Md = 0, IQR = 0) compared to the control group (Md = 0, IQR = 0 - 3), p = 0.043. We found no evidence of differences in reported pain between the groups (Silicone - Md = 1.15, IQR 0.3 - 4.5 vs control group - Md = 1.5, IQR 0.6 - 3.8, z = -0.63, p = 0.53). No other differences were observed, and no adverse events were associated with the topical silicone in the study whereas an infection and a reaction were experienced in the control group.

CONCLUSION

Film-forming silicone gel had comparable effects to standard of care emollient on wound healing of superficial partial thickness burns of the face and neck. Silicone treated wounds were associated with a significant improvement in scar pigmentation outcome at six weeks post-burn.

Influence of Moisturizers on Skin Microcirculation: An Assessment Study Using Laser Speckle Contrast Imaging

Non-invasive scar management typically involves pressure therapy, hydration with silicones or moisturizers, and UV protection. Moisture loss from scars can lead to hypertrophic scar formation. Pressure therapy reduces blood flow, fibroblast activity, and transforming growth factor beta 1 (TGF-β1) release. This study examined various moisturizers and liquid silicone gel's impact on microcirculation. 40 volunteers participated in a study where superficial abrasions were created to induce trans epidermal water loss (TEWL). Five moisturizers (TEDRA®, TEDRA® NT1, TEDRA® NT3, Alhydran®, Lipikar®) and BAP Scar Care® silicone gel were tested. TEWL, hydration, and blood flow were measured up to 4 h post-application. Results showed that silicone had the least impact on occlusion and hydration. Alhydran® reduced blood flow the most, while Lipikar® increased it the most. TEDRA® NT1 had reduced flow compared to TEDRA® and TEDRA® NT3. All TEDRA® products exhibited high hydration, and all but silicone showed good occlusion. Moisturizers influenced skin microcirculation, with some causing decrease, while others increased flow. However, the clinical impact on scarring remains unclear compared to the evident effects of hydration and occlusion. More research is necessary to study moisturizers alone and with pressure therapy on scars, along with potential adverse effects of increased microcirculation on scars.

Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies

Hypertrophic scars and keloids can have significant detrimental effects on patients both psychosocially and functionally. A careful identification of patient risk factors and a comprehensive management plan are necessary to optimize outcomes. Patients with a history of dystrophic scarring should avoid unnecessary procedures and enhance the wound-healing process using various preventive strategies. As there is no single, fully efficacious treatment modality, prevention remains the best approach in reducing aberrant scar formation. When prevention therapies fail, keloids have been shown to be respond to a variety of therapies including topical and injectable corticosteroids, 5-fluorouracil, radiotherapy, lasers, and surgical excision, all with varying efficacies. As such, management should be tailored to the individual patient's risk factors with the use of combination therapies to reduce recurrence rates. Still, keloid and hypertrophic scar therapies are widely diverse with novel treatment modalities providing alternatives for recurring lesions. Laser-assisted drug delivery, skin priming, and novel topical therapies may provide alternative options for the management of hypertrophic scars and keloids.

Occlusion and hydration of scars: moisturizers versus silicone gels

BACKGROUND

The mainstay of non-invasive scar management, consists of pressure therapy with customized pressure garments often combined with inlays, hydration by means of silicones and/or moisturizers as well as UV protection. It is generally accepted that scar dehydration resulting from impaired barrier function of the stratum corneum and expressed by raised trans epidermal water loss (TEWL) values, can lead to increased fibroblast activity and thereby hypertrophic scar formation. However, we have reached no consensus on exactly what optimal scar hydration is nor on barrier function repair: by means of silicone sheets, liquid silicone gels or moisturizers. Occlusive silicone sheets almost completely prevent TEWL and have been shown to be effective. Nevertheless, many important disadvantages due to excessive occlusion such as difficulties in applying the sheets exceeding 10-12 h, pruritus, irritation, and maceration of the skin are limiting factors for its use. To avoid these complications and to facilitate the application, liquid silicone gels were developed. Despite a reduced occlusion, various studies have shown that the effects are comparable to these of the silicone sheets. However, major limiting factors for general use are the long drying time, the shiny aspect after application, and the high cost especially when used for larger scars. Based on excellent clinical results after using three specific moisturizers for scar treatment in our patients, we wanted to investigate whether these moisturizers induce comparable occlusion and hydration compared to both each other and the widely recognized liquid silicone gels. We wanted to provide a more scientific basis for the kind of moisturizers that can be used as a full-fledged and cost-effective alternative to silicone gel.

METHODS

A total of 36 healthy volunteers participated in this study. Increased TEWL was created by inducing superficial abrasions by rigorous (20x) skin stripping with Corneofix® adhesive tape in squares of 4 cm². Three moisturizers and a fluid silicone gel were tested: DermaCress, Alhydran, Lipikar and BAP Scar Care silicone gel respectively. TEWL reducing capacities and both absolute (AAH) and cumulative (CAAH) absolute added hydration were assessed using a Tewameter® TM300 and a Corneometer® CM825 at different time points for up to 4 h after application.

RESULTS

We found an immediate TEWL increase in all the zones that underwent superficial abrasions by stripping. Controls remained stable over time, relative to the ambient condition. The mean percentage reduction (MPR) in TEWL kept increasing over time with Alhydran and DermaCress, reaching a maximum effect 4 h after application. Silicone gel reached maximal MPR almost immediately after application and only declined thereafter. The silicone gel never reached the minimal MPR of Alhydran or DermaCress. Hydration capacity assessed through CAAH as measured by the Corneometer was significantly less with silicone gel compared to the moisturizers. Compared to silicone gel Lipikar provided similar occlusion and the improvement in hydration was highly significant 4 h after application.

CONCLUSION

Based on the results of both our previous research and this study it is clearly demonstrated that the occlusive and hydrative effect of fluid silicone gel is inferior to the moisturizers used in our center. Lipikar hydrates well but is less suitable for scar treatment due to the lack of occlusion. A well-balanced occlusion and hydration, in this study only provided by Alhydran and DermaCress, suggests that moisturizers can be used as a scar hydration therapy that replaces silicone products, is more cost-effective and has a more patient-friendly application.

Simvastatin cream alleviates dermal fibrosis in a rabbit ear hypertrophic scar model

BACKGROUND

Hypertrophic scars (HTS) result from injury to the skin and represent a clinical burden with limited treatment options. Previously, we demonstrated that statin drugs could attenuate HTS formation, but convenient topical delivery and retention of these drugs at the wound site remains a challenge.

AIMS

Here, we aimed to develop a topical cream formulation that can deliver statin drugs simply and conveniently to reduce scar hypertrophy.

METHODS

We formulated creams containing 10% pravastatin, 2% simvastatin, and 10% simvastatin. We tested these creams for their ability to reduce scar hypertrophy and attenuate dermal fibrosis in a clinically relevant HTS wound model performed in rabbit ear skin. We also monitored trans-epidermal water loss (TEWL) over the course of wound healing in order to understand the effects of statin treatment on epidermal barrier recovery.

RESULTS

Of the three creams formulated, only application of 10% simvastatin cream significantly attenuated hypertrophy of resultant scars compared with vehicle cream application. Application of 10% simvastatin cream resulted in a decrease in macrophage and myofibroblast density at post-operative day 28 (POD28) harvest. Application of 10% simvastatin cream resulted in visible symptoms of dryness and increased TEWL at POD28, but subsequent withdrawal of statin cream treatment resulted in rapid alleviation of dryness and decrease in TEWL back to normal levels.

CONCLUSIONS

Our data demonstrate that topical administration of 10% simvastatin cream antagonizes dermal fibrosis and reduces hypertrophy in an HTS model, and withdrawal of the cream enables recovery of epidermal barrier and resolution of skin dryness.

The use of occlusive dressings: influence on excisional wound healing in animal model

PURPOSE

To analyze the influence of occlusive dressing on the healing of excisional skin wounds in mice.

METHODS

Pre-clinical, comparative, and translational study. Mice were divided into three experimental groups: wounds occluded with hydrocolloid (HD) dressings, transparent polyurethane film (TF) dressings, and without occlusion (WO), monitored at three, six and 14 days, with eight animals each. Closure rate, infiltration of neutrophils and macrophages, measurement of tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) and, histologically, angiogenesis were evaluated.

RESULTS

Wound closure was accelerated in the occlusive groups. There was a decrease in TNF-α levels in the HD group when compared to the WO and TF groups. Neutrophils accumulation decreased in the HD group. Increased dosages of macrophages were evidenced in the HD group, compared to the WO and TF groups. Levels of VEGF were increased in the TF and HD groups.

CONCLUSIONS

It is suggested that the occlusion of wounds modulates the inflammatory response.

The case for considering volar skin in a "separate status" for wound healing

Foot ulcers, particularly in the diabetic setting, are a major medical and socioeconomic challenge. While the effects of diabetes and its various sequelae have been extensively studied, in the wound field it is commonly assumed that the wound healing process is essentially identical between different skin types, despite the many well-known specializations in palmoplantar skin, most of which are presumed to be evolutionary adaptations for weightbearing. This article will examine how these specializations could alter the wound healing trajectory and contribute to the pathology of foot ulcers.

Vascular and Collagen Target: A Rational Approach to Hypertrophic Scar Management

Significance: Hypertrophic scarring is a challenging issue for patients and clinicians. The prevalence of hypertrophic scarring can be up to 70% after burns, and patients suffer from pain, itching, and loss of joint mobility. To date, the exact mechanisms underlying hypertrophic scar formation are unclear, and clinical options remain limited. Recent Advances: Several studies have demonstrated that pathological scars are a type of hyperactive vascular response to wounding. Scar regression has been found to be accompanied by microvessel occlusion, which causes severe hypoxia, malnutrition, and endothelial dysfunction, suggesting the essential roles of microvessels in scar regression. Therefore, interventions that target the vasculature, such as intense pulsed light, pulsed dye lasers, vascular endothelial growth factor antibodies, and Endostar, represent potential treatments. In addition, the mass of scar-associated collagen is usually not considered by current treatments. However, collagen-targeted therapies such as fractional CO₂ laser and collagenase have shown promising outcomes in scar treatment. Critical Issues: Traditional modalities used in current clinical practice only partially target scar-associated microvessels or collagen. As a result, the effectiveness of current treatments is limited and is too often accompanied by undesirable side effects. The formation of scars in the early stage is mainly affected by microvessels, whereas the scars in later stages are mostly composed of residual collagen. Traditional therapies do not utilize specific targets for scars at different stages. Therefore, more precise treatment strategies are needed. Future Directions: Scars should be classified as either "vascular-dominant" or "collagen-dominant" before selecting a treatment. In this way, strategies that are vascular-targeted, collagen-targeted, or a combination thereof could be recommended to treat scars at different stages.

V-EMF treatment of facial scar: First results

AIM OF STUDY

This is a retrospective study aimed at evaluating the effectiveness of the use of electromagnetic fields and negative pressure treatment (V-EMF) for facial scars, from an aesthetic and functional point of view, and considering the variations in the levels of hydration.

MATERIAL AND METHODS

25 subjects with facial scarring were re-evaluated after being treated with the V-EMF method. The hydration levels of the scars before and after treatment were compared. The results were evaluated considering the satisfaction levels of the patients with the VAS, and of the medical specialists who performed the treatment, and of 3 independent dermatologists with the Likert scale.

RESULTS

Mean hydration levels of scars went from 41.8 to 53.3, with mean hydration levels of healthy reference points equal to 54.6. The minimum patient satisfaction level was 2 in the VAS. The minimum level of satisfaction of specialists and dermatologists was equal to IV on the Likert scale for all patients, except for 1 subject in which it was III for the specialist who had treated him. Anti-aging and re-pigmentation effects were also noted as secondary results.

CONCLUSIONS

From an aesthetic and functional point of view, and for the overall anti-aging effect of the treated area, V-EMF applied to facial scars has shown extremely promising results.

Wound fluid under occlusive dressings from diabetic patients show an increased angiogenic response and fibroblast migration

INTRODUCTION

Metabolic diseases like diabetes mellitus often show prolonged healing and chronic wounds. Occlusive wound dressings are known to support wound closure by creating a moist environment which supports collagen synthesis, epithelialization and angiogenesis. We aimed to assess the effect of occlusion on diabetic wound fluid on the cellular level regarding fibroblast activity and angiogenetic response.

MATERIAL AND METHODS

22 split skin donor sites from 22 patients (11 patients with diabetes mellitus) were treated with occlusive dressings intraoperatively. On day 3, fluid and blood serum samples were harvested while changing the dressings. The influence of wound fluid on fibroblasts was assessed by measuring metabolic activity (Alamar Blue assay, Casey Counter), cell stress/death (LDH assay) and migration (in vitro wound healing assay) of fibroblasts. Angiogenesis of endothelial cells (HUVEC) was analyzed with the tube formation assay. Furthermore, a Magnetic Luminex Assay for multi-cytokines detection was performed focusing on inflammatory and pro-angiogenetic cytokines.

RESULTS

The influence of wound fluid under occlusive dressings from diabetic patients showed a significantly increased angiogenic response and fibroblast migration compared to the non-diabetic patient group. Additionally, cell stress was increased in the diabetic group. Cytokine analysis showed an increase in VEGF-A in the diabetic group.

CONCLUSION

Occlusive dressings may stimulate regenerative effects in diabetic wounds. Our in-vitro study shows the influence of wound fluid under occlusive dressings from diabetic patients on angiogenesis, migration and proliferation of fibroblasts, which are essential modulators of wound healing and scar modulation.

Hydrocolloid dressings can be used to treat hypertrophic scars: An outpatient dermatology service devoted to treat keloids and challenging scars

Since we first described the rationale for the use of hydrocolloid dressings to treat keloids and hypertrophic scars, this technique has been used as an occlusive therapy alternative to the use of silicone sheets in our outpatient clinic. In this paper, we describe the use of these dressings on two patients with challenging scars: a large postburn hypertrophic scar on a young patient's hand and arm, with a growing keloid on the wrist, and a progressive scar on the lower eyelid, developing after a complication of a cosmetic blepharoplasty procedure, leading to ectropium. The methods on the proper use of these dressings are reviewed here in detail. Larger clinical trials are needed to further evaluate this technique in the treatment of hypertrophic scars and keloids.

Inflammation as an orchestrator of cutaneous scar formation: a review of the literature

Inflammation is a key phase in the cutaneous wound repair process. The activation of inflammatory cells is critical for preventing infection in contaminated wounds and results in the release of an array of mediators, some of which stimulate the activity of keratinocytes, endothelial cells, and fibroblasts to aid in the repair process. However, there is an abundance of data suggesting that the strength of the inflammatory response early in the healing process correlates directly with the amount of scar tissue that will eventually form. This review will summarize the literature related to inflammation and cutaneous scar formation, highlight recent discoveries, and discuss potential treatment modalities that target inflammation to minimize scarring.

Knockdown of sodium channel Nax reduces dermatitis symptoms in rabbit skin

The skin plays a critical role in maintenance of water homeostasis. Dysfunction of the skin barrier causes not only delayed wound healing and hypertrophic scarring, but it also contributes to the development of various skin diseases. Dermatitis is a chronic inflammatory skin disorder that has several different subtypes. Skin of contact dermatitis and atopic dermatitis (AD) show epidermal barrier dysfunction. Na_x is a sodium channel that regulates inflammatory gene expression in response to perturbation of barrier function of the skin. We found that in vivo knockdown of Na_x using RNAi reduced hyperkeratosis and keratinocyte hyperproliferation in rabbit ear dermatitic skin. Increased infiltration of inflammatory cells (mast cells, eosinophils, T cells, and macrophages), a characteristic of dermatitis, was reduced by Na_x knockdown. Upregulation of PAR-2 and thymic stromal lymphopoietin (TSLP), which induce Th2-mediated allergic responses, was inhibited by Na_x knockdown. In addition, expression of COX-2, IL-1β, IL-8, and S100A9, which are downstream genes of Na_x and are involved in dermatitis pathogenesis, were also decreased by Na_x knockdown. Our data show that knockdown of Na_x relieved dermatitis symptoms in vivo and indicate that Na_x is a novel therapeutic target for dermatitis, which currently has limited therapeutic options.

Sprayable and biodegradable, intrinsically adhesive wound dressing with antimicrobial properties

Conventional wound dressings are difficult to apply to large total body surface area (TBSA) wounds, as they typically are prefabricated, require a layer of adhesive coating for fixation, and need frequent replacement for entrapped exudate. Large TBSA wounds as well as orthopedic trauma and low-resource surgery also have a high risk of infection. In this report, a sprayable and intrinsically adhesive wound dressing loaded with antimicrobial silver is investigated that provides personalized fabrication with minimal patient contact. The dressing is composed of adhesive and biodegradable poly(lactic-co-glycolic acid) and poly(ethylene glycol) (PLGA/PEG) blend fibers with or without silver salt (AgNO3). in vitro studies demonstrate that the PLGA/PEG/Ag dressing has antimicrobial properties and low cytotoxicity, with antimicrobial silver controllably released over 7-14 days. In a porcine partial-thickness wound model, the wounds treated with both antimicrobial and nonantimicrobial PLGA/PEG dressings heal at rates similar to those of the clinical, thin film polyurethane wound dressing, with similar scarring. However, PLGA/PEG adds a number of features beneficial for wound healing: greater exudate absorption, integration into the wound, a 25% reduction in dressing changes, and tissue regeneration with greater vascularization. There is also modest improvement in epidermis thickness compared to the control wound dressing.

Occlusive dressing-induced secretomes influence the migration and proliferation of mesenchymal stem cells and fibroblasts differently

Background

Fingertip injuries treated with occlusive dressings (ODs) lead to nearly scar-free, functionally, and aesthetically pleasing results. We hypothesized that paracrine factors in the wound fluid (secretome) may influence migration and proliferation of mesenchymal stem cells (MSCs) and fibroblasts and modulate the wound-healing process.

Methods

We could collect wound fluid samples from 4 fingertip injuries and 7 split skin donor sites at the 5th day during dressing change. Blood serum samples served as controls. The proliferation rate of MSCs and fibroblasts (HS27) was continuously measured through impedance analysis for 60 h and by Alamarblue analysis after 72 h. Cell migration was evaluated continuously for 15 h and confirmed by the in vitro wound-healing assay.

Results

Migration of MSCs under the influence of both wound fluids was significantly faster than controls from 4 to 6 h after incubation and reversed after 9 h. MSC proliferation in wound fluid groups showed a significant increase at 5 and 10 h and was significantly decreased after 45 h. Fibroblasts in wound fluid groups showed overall a significant increase in migration and a significant decrease in proliferation compared to controls.

Conclusion

OD-induced secretomes influence MSCs and fibroblasts and thereby possibly modulate wound healing and scar tissue formation.

Growth hormone-releasing peptide 6 prevents cutaneous hypertrophic scarring: early mechanistic data from a proteome study

Hypertrophic scars (HTS) and keloids are forms of aberrant cutaneous healing with excessive extracellular matrix (ECM) deposition. Current therapies still fall short and cause undesired effects. We aimed to thoroughly evaluate the ability of growth hormone releasing peptide 6 (GHRP6) to both prevent and reverse cutaneous fibrosis and to acquire the earliest proteome data supporting GHRP6's acute impact on aesthetic wound healing. Two independent sets of experiments addressing prevention and reversion effects were conducted on the classic HTS model in rabbits. In the prevention approach, the wounds were assigned to topically receive GHRP6, triamcinolone acetonide (TA), or vehicle (1% sodium carboxy methylcellulose [CMC]) from day 1 to day 30 post-wounding. The reversion scheme was based on the infiltration of either GHRP6 or sterile saline in mature HTS for 4 consecutive weeks. The incidence and appearance of HTS were systematically monitored. The sub-epidermal fibrotic core area of HTS was ultrasonographically determined, and the scar elevation index was calculated on haematoxylin/eosin-stained, microscopic digitised images. Tissue samples were collected for proteomics after 1 hour of HTS induction and treatment with either GHRP6 or vehicle. GHRP6 prevented the onset of HTS without the untoward reactions induced by the first-line treatment triamcinolone acetonide (TA); however, it failed to significantly reverse mature HTS. The preliminary proteomic study suggests that the anti-fibrotic preventing effect exerted by GHRP6 depends on different pathways involved in lipid metabolism, cytoskeleton arrangements, epidermal cells' differentiation, and ECM dynamics. These results enlighten the potential success of GHRP6 as one of the incoming alternatives for HTS prevention.

Epidermal HMGB1 Activates Dermal Fibroblasts and Causes Hypertrophic Scar Formation in Reduced Hydration

HMGB1 protein is a multifunctional cytokine involved in inflammatory reactions and is known to play a key role in tissue repair and fibrosis. However, the function of HMGB1 in fibrotic skin diseases, such as hypertrophic scar formation, remains unclear. In this study, HMGB1 was detected in the nuclei of epidermal cells in normal skin and had accumulated in the cytoplasm in hypertrophic scars. By establishing a keratinocyte-fibroblast co-culture and conditional medium treatment models, we found that a reduced hydration condition increased the expression and secretion of HMGB1 in keratinocytes, subsequently activating dermal fibroblasts. HMGB1 secreted from keratinocytes activated fibroblasts by promoting the nuclear import of MRTF-A, increased the nuclear accumulation of MRTF-A/SRF complexes and consequently enhanced α-smooth muscle actin promoter activation. Moreover, blockade of advanced glycation end products or Toll-like receptor 2/4 inhibited the fibroblast activation induced by HMGB1. Finally, local delivery of HMGB1 resulted in marked hypertrophic scar formation in rabbit hypertrophic scar models, while HMGB1 blockade exerted a clear anti-scarring effect. Our results indicate that high HMGB1 levels induced by a reduced hydration status play an important role in hypertrophic scar formation, strongly suggesting that HMGB1 is a novel target for preventing scarring.

Labeling of Cosmetic Products

The labeling of cosmetic products provides a set of obligations, as reported in the Regulation 1223/2009, which came into force in Europe in July 2013. The indications reported on the label are intended to enable the clear identification of the functionality and proper use of cosmetics, ensure the protection of the consumer from the commercial aspects and, above all, from the safety point of view. Moreover, it should allow quick tracing of the product details and all info of toxicological relevance. However, the misuse of this tool often leads, on one side, to confusion among cosmetics, pharmaceuticals, medical devices, and biocides. On the other side, it gives rise to fanciful interpretations by a huge number of web users, who pretend to be able to judge the quality of a cosmetic product just by reading the ingredients list. This article points out the concrete purpose of cosmetic labels, in order to shed light on the use of certain categories of ‘controversial’ ingredients and on the real quality concepts of cosmetic products. Indeed, when properly interpreted, cosmetic labels represent a good tool for the professional investigation of adverse reactions to cosmetics.

Wound bed preparation: A novel approach using HydroTherapy

Wounds that fail to heal quickly are often encountered by community nursing staff. An important step in assisting these chronic or stalled wounds progress through healing is debridement to remove devitalised tissue, including slough and eschar, that can prevent the wound from healing. A unique wound treatment called HydroTherapy aims to provide an optimal healing environment. The first step of HydroTherapy involves HydroClean plus™, this dressing enables removal of devitalised tissue through autolytic debridement and absorption of wound fluid. Irrigation and cleansing provided by Ringer's solution from the dressing further removes any necrotic tissue or eschar. Once effective wound bed preparation has been achieved a second dressing, HydroTac™, provides an ongoing hydrated wound environment that enables re-epithelialisation to occur in an unrestricted fashion. This paper presents 3 case studies of slow healing wounds treated with HydroClean plus™ which demonstrates effective wound debridement.

A 3D self-organizing multicellular epidermis model of barrier formation and hydration with realistic cell morphology based on EPISIM

The epidermis and the stratum corneum (SC) as its outermost layer have evolved to protect the body from evaporative water loss to the environment. To morphologically represent the extremely flattened cells of the SC - and thereby the epidermal barrier - in a multicellular computational model, we developed a 3D biomechanical model (BM) based on ellipsoid cell shapes. We integrated the BM in the multicellular modelling and simulation platform EPISIM. We created a cell behavioural model (CBM) with EPISIM encompassing regulatory feedback loops between the epidermal barrier, water loss to the environment, and water and calcium flow within the tissue. This CBM allows a small number of stem cells to initiate self-organizing epidermal stratification, yielding the spontaneous emergence of water and calcium gradients comparable to experimental data. We find that the 3D in silico epidermis attains homeostasis most quickly at high ambient humidity, and once in homeostasis the epidermal barrier robustly buffers changes in humidity. Our model yields an in silico epidermis with a previously unattained realistic morphology, whose cell neighbour topology is validated with experimental data obtained from in vivo images. This work paves the way to computationally investigate how an impaired SC barrier precipitates disease.

Comparative evaluation of the wound-healing potency of recombinant bFGF and ski gene therapy in rats

We previously demonstrated that cellular Sloan-Kettering Institute (c-Ski) played a dual role, both promoting wound healing and alleviating scar formation. However, its mechanism and therapeutic effects are not clear, especially compared with widely used treatments, such as basic fibroblast growth factor (bFGF) administration. However, Ski treatment led to an even shorter healing time and a more significant reduction in scar area than bFGF treatment. The mechanism underlying this difference was related to a reduced inflammatory response, more rapid re-epithelialization, less collagen after healing and a greater reduction in the proportion of alpha-smooth muscle actin and SMemb-positive cells after Ski treatment. These results not only confirm that Ski plays a dual role in promoting healing and reducing scarring but also suggest that Ski yields better treatment effects than bFGF, indicating better potential therapeutic effects in wound repair.

The importance of hydration in wound healing: reinvigorating the clinical perspective

Balancing skin hydration levels is important as any disruption in skin integrity will result in disturbance of the dermal water balance. The discovery that a moist environment actively supports the healing response when compared with a dry environment highlights the importance of water and good hydration levels for optimal healing. The benefits of 'wet' or 'hyper-hydrated' wound healing appear similar to those offered by moist over a dry environment. This suggests that the presence of free water may not be detrimental to healing, but any adverse effects of wound fluid on tissues is more likely related to the biological components contained within chronic wound exudate, for example elevated protease levels. Appropriate dressings applied to wounds must not only be able to absorb the exudate, but also retain this excess fluid together with its protease solutes, while concurrently preventing desiccation. This is particularly important in the case of chronic wounds where peri-wound skin barrier properties are compromised and there is increased permeation across the injured skin. This review discusses the importance of appropriate levels of hydration in skin, with a particular focus on the need for optimal hydration levels for effective healing. Declaration of interest: This paper was supported by Paul Hartmann Ltd. The authors have provided consultative services to Paul Hartmann Ltd.

The Use of Silicone Adhesives for Scar Reduction

Significance: This article discusses the history and developments of silicone gel sheeting (SGS) scar therapy. Furthermore, we review a breadth of literature to gain an insight into how and why topical silicone gels remain the favored treatment of medical experts in scar management. We also analyze an ever increasing number of alternative therapies claiming to provide enhanced scar reduction performance. Recent Advances: Topical silicone gel treatments seem to remain the first point of clinical recommendation in scar management. SGS has been used in scar therapy for over 30 years, during which its efficacy has been the subject of numerous clinical evaluations. Critical Issues: While the exact mechanisms by which SGS improves hypertrophic scars, keloid development and recovery are yet to be fully agreed upon, its ability to do so remains largely undisputed at present. However, there still is ongoing deliberation over the exact mechanism of action of silicone in improving a scar. At present it is likely that through occlusion of the scar site and hydration of the wound bed, the overactivity of scar-related cells is suppressed, and their activity normalized. Future Direction: The clinical support of topical silicone gel products, relative to all alternative scar therapies, is considered the internationally recommended first-line form of scar management, and favored by consensus among healthcare professionals. However, there still remains the need for further clinical evidence and a better understanding of the mechanism behind the benefit of silicone gel for use in the prevention of abnormal scarring.

Hydration status regulates sodium flux and inflammatory pathways through epithelial sodium channel (ENaC) in the skin

Although it is known that the inflammatory response that results from disruption of epithelial barrier function after injury results in excessive scarring, the upstream signals remain unknown. It has also been observed that epithelial disruption results in reduced hydration status and that the use of occlusive dressings that prevent water loss from wounds decreases scar formation. We hypothesized that hydration status changes sodium homeostasis and induces sodium flux in keratinocytes, which result in activation of pathways responsible for keratinocyte-fibroblast signaling and ultimately lead to activation of fibroblasts. Here, we demonstrate that perturbations in epithelial barrier function lead to increased sodium flux in keratinocytes. We identified that sodium flux in keratinocytes is mediated by epithelial sodium channels (ENaCs) and causes increased secretion of proinflammatory cytokines, which activate fibroblast via the cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) pathway. Similar changes in signal transduction and sodium flux occur by increased sodium concentration, which simulates reduced hydration, in the media in epithelial cultures or human ex vivo skin cultures. Blockade of ENaC, prostaglandin synthesis, or PGE2 receptors all reduce markers of fibroblast activation and collagen synthesis. In addition, employing a validated in vivo excessive scar model in the rabbit ear, we demonstrate that utilization of either an ENaC blocker or a COX-2 inhibitor results in a marked reduction in scarring. Other experiments demonstrate that the activation of COX-2 in response to increased sodium flux is mediated through the PIK3/Akt pathway. Our results indicate that ENaC responds to small changes in sodium concentration with inflammatory mediators and suggest that the ENaC pathway is a potential target for a strategy to prevent fibrosis.

Intrinsic differences between oral and skin keratinocytes

Keratinocytes cover both the skin and some oral mucosa, but the morphology of each tissue and the behavior of the keratinocytes from these two sites are different. One significant dissimilarity between the two sites is the response to injury. Oral mucosal wounds heal faster and with less inflammation than equivalent cutaneous wounds. We hypothesized that oral and skin keratinocytes might have intrinsic differences at baseline as well as in the response to injury, and that such differences would be reflected in gene expression profiles.

Efficacy and Tolerability of a New Pharmaceutical Form of Betamethasone Valerate in the Prevention of Hypertrophic Scars following Anterior Trunk Plastic Surgery: A Preliminary Exploratory Study

Hypertrophic scars are fibroproliferative diseases of the skin. Many treatment options are now available, but none is completely effective. The primary objective of this study was to compare the efficacy of a betamethasone valerate (BMV) 2.25 mg plaster versus no treatment in the prevention of hypertrophic scars after anterior trunk plastic surgery. An exploratory, open, prospective, controlled study was carried out on 16 consecutive patients with postoperative wounds. A 12-week daily treatment was initiated after wounds cicatrisation. The effect of a daily application of the plaster was compared to no treatment by dividing the wound into 2–4 parts. The wound evaluation was performed during the treatment period at 2, 4, 8 and 12 weeks, and 6 months after the end of the treatment. A total of 60 wounds was evaluated. Pain and itching improved in both groups after 12 weeks. However, only the wounds treated with BMV plaster showed a significantly greater and more rapid improvement as compared with the non-treated wounds after 4 and 8 weeks of treatment in all the evaluated parameters (p<0.0001). The efficacy and tolerability of BMV plaster in the prevention of hypertrophic scar development is promising.

Epidermal Differentiation in Barrier Maintenance and Wound Healing

Significance: The epidermal barrier prevents water loss and serves as the body's first line of defense against toxins, chemicals, and infectious microbes. Disruption of the barrier, either through congenital disorders of barrier formation or through wounds, puts the individual at risk for dehydration, hypersensitivity, infection, and prolonged inflammation. Epidermal barrier disorders affect millions of patients in the United States, causing loss of productivity and diminished quality of life for patients and their families, and represent a burden to the health-care system and society. Recent Advances: The genetic basis of many congenital barrier disorders has been identified in recent years, and great advances have been made in the molecular mechanisms of the formation and homeostasis of epidermal barrier, as well as acute and chronic wound healing. Progress in stem cell (SC) biology, particularly in induced pluripotent stem cells (iPSCs) and allogeneic mesenchymal stem cells (MSCs), has opened new doors for cell-based therapy of chronic wounds. Critical Issues: Understanding of the molecular mechanisms of barrier homeostasis in health and disease, as well as contributions of iPSCs and allogeneic MSCs to wound healing, will lead to the identification of novel targets for developing therapeutics for congenital barrier and wound healing disorders. Future Directions: Future studies should focus on better understanding of molecular mechanisms leading to disrupted homeostasis of epidermal barrier to identify potential therapeutic targets to combat its associated diseases.

In vivo inhibition of hypertrophic scars by implantable ginsenoside-Rg3-loaded electrospun fibrous membranes

Clinically, hypertrophic scarring (HS) is a major concern for patients and has been a challenge for surgeons, as there is a lack of treatments that can intervene early in the formation of HS. This study reports on a Chinese drug, 20(R)-ginsenoside Rg3 (GS-Rg3), which can inhibit in vivo the early formation of HS and later HS hyperplasia by inducing the apoptosis of fibroblasts, inhibiting inflammation and down-regulating VEGF expression. Implantable biodegradable GS-Rg3-loaded poly(l-lactide) (PLA) fibrous membranes were successfully fabricated using co-electrospinning technology to control drug release and improve drug utilization. The in vivo releasing time of GS-Rg3 lasts for 3 months, and the drug concentration released in rabbits can be controlled by varying the drug content of the electrospun fibers. Histological observations of HE staining indicate that GS-Rg3/PLA significantly inhibits the HS formation, with obvious improvements in terms of dermis layer thickness, epidermis layer thickness and fibroblast proliferation. The results of immunohistochemistry staining and Masson's trichrome staining demonstrate that GS-Rg3/PLA electrospun fibrous membranes significantly inhibit HS formation, with decreased expression of collagen fibers and microvessels. VEGF protein levels are much lower in the group treated with GS-Rg3/PLA eletrospun membranes compared with other groups. These results demonstrate that GS-Rg3 is a novel drug, capable of inhibiting the early formation of HS and later HS hyperplasia. GS-Rg3/PLA electrospun membrane is a very promising new treatment for early and long-term treatment of HS.

The effects of topical agent (kelo-cote or contractubex) massage on the thickness of post-burn scar tissue formed in rats

Background

We conducted an experimental study to compare the effect of massage using topical agents (Kelo-cote or Contractubex) on scar formation by massaging the healed burn wound on the dorsal area of Sprague-Dawley (SD) rats.

Methods

Four areas of second degree contact burn were made on the dorsal area of each of 15 SD rats, using a soldering iron 15 mm in diameter. After gross epithelialization in the defect, 15 SD rats were randomly divided into four groups: the Kelo-cote group, Contractubex group, Vaseline group, and control group. Rats in three of the groups (all but the Control group) were massaged twice per day for 5 minutes each day, while those in the Control group were left unattended. For histologic analysis, we performed a biopsy and evaluated the thickness of scar tissue.

Results

In the Kelo-cote and Contractubex groups, scar tissue thicknesses showed a significant decrease, compared with the Vaseline and control groups. However, no significant differences were observed between the Kelo-cote and Contractubex groups. In the Vaseline group, scar tissue thicknesses showed a significant decrease, compared with the control groups.

Conclusions

The findings of this study suggest that massage using a topical agent is helpful in the prevention of scar formation and that massage only with lubricant (no use of a topical agent) also has a considerable effect, although not as much as the use of a topical agent. Thus, we recommend massage with a topical agent on the post-burn scar as an effective method for decreasing the scar thickness.

The expression of proinflammatory genes in epidermal keratinocytes is regulated by hydration status

Mucosal wounds heal more rapidly, exhibit less inflammation, and are associated with minimal scarring when compared with equivalent cutaneous wounds. We previously demonstrated that cutaneous epithelium exhibits an exaggerated response to injury compared with mucosal epithelium. We hypothesized that treatment of injured skin with a semiocclusive dressing preserves the hydration of the skin and results in a wound healing phenotype that more closely resembles that of mucosa. Here we explored whether changes in hydration status alter epidermal gene expression patterns in rabbit partial-thickness incisional wounds. Using microarray studies on injured epidermis, we showed that global gene expression patterns in highly occluded versus non-occluded wounds are distinct. Many genes including IL-1β, IL-8, TNF-α (tumor necrosis factor-α), and COX-2 (cyclooxygenase 2) are upregulated in non-occluded wounds compared with highly occluded wounds. In addition, decreased levels of hydration resulted in an increased expression of proinflammatory genes in human ex vivo skin culture (HESC) and stratified keratinocytes. Hierarchical analysis of genes using RNA interference showed that both TNF-α and IL-1β regulate the expression of IL-8 through independent pathways in response to reduced hydration. Furthermore, both gene knockdown and pharmacological inhibition studies showed that COX-2 mediates the TNF-α/IL-8 pathway by increasing the production of prostaglandin E2 (PGE2). IL-8 in turn controls the production of matrix metalloproteinase-9 in keratinocytes. Our data show that hydration status directly affects the expression of inflammatory signaling in the epidermis. The identification of genes involved in the epithelial hydration pathway provides an opportunity to develop strategies to reduce scarring and optimize wound healing.

Scar management by means of occlusion and hydration: a comparative study of silicones versus a hydrating gel-cream

Despite the worldwide use of silicones in scar management, its exact working mechanism based on a balanced occlusion and hydration, is still not completely elucidated. Moreover, it seems peculiar that silicones with completely different occlusive and hydrating properties still could provide a similar therapeutic effect. The objective of the first part of this study was to compare the occlusive and hydrating properties of three fluid silicone gels and a hydrating gel-cream. In a second part of the study these results were compared with those of silicone gel sheets. Tape stripped skin was used as a standardized scar like model on both forearms of 40 healthy volunteers. At specific times, trans epidermal water loss (TEWL) and the hydration state of the stratum corneum were measured and compared with intact skin and a scar-like control over a 3-4h period. Our study clearly demonstrated that fluid silicone gels and a hydrating gel-cream have comparable occlusive and hydrating properties while silicone gel sheets are much more occlusive, reducing TEWL values far below those of normal skin. A well-balanced, hydrating gel-cream can provide the same occlusive and hydrating properties as fluid silicone gels, suggesting that it could eventually replace silicones in scar treatment.

Linear scar reduction using silicone gel sheets in individuals with normal healing

OBJECTIVE

To examine the application of silicone gel sheets on linear scars due to surgical procedures.

METHOD

Ten individuals, with scars less than I year old, participated in the study. The Participant and Observer Scar Assessment Scale (POSAS) was used to evaluate scars on seven characteristics rated by visual analogue scales 0fAS). Participants applied silicone gel sheets to half of their scar for 6 months, and every 2 weeks POSAS data forms were completed. Linear mixed-effects analysis of variances (ANOVA)were used to determine if significant differences occurred between groups (treated and untreated scarsides) across the 6 months of data collection. To see if differences were found from the initial evaluation to final visit, Mann-Whitney U tests analysed between-group changes (treated and untreated scar sides), while Wilcoxon signed ranks tests compared within-group changes (evaluation of each scar side over time).

RESULTS

No significant differences in VAS ratings were observed when the two scar sides were compared, with the exception of overall opinion of the scar, as rated by an observer. For each group,significant changes from baseline to study end were observed for colour, stiffness and irregularities, as rated by the participant. Significant improvements for the treated versus untreated group were observed for pliability and pigmentation, as rated by the observer scale.

CONCLUSION

There was no evidence for improved healing when using silicone gel sheets. The results do not support using silicone gel sheets on linear scars for individuals with no history of abnormal scarring.

A review of the effects of moisturizers on the appearance of scars and striae

Scars are well known to have a stratum corneum (SC) that is malfunctional. Increases in transepidermal water loss and decreases in SC capacitance and conductance have been reported. Occlusion therapy is a well-known route to improving the signs and symptoms of scarring. Until recently that has been assumed to be totally pressure related. However, studies have demonstrated that the direct effects of hydration on keratinocytes and fibroblasts contribute to the reduction in hypertrophic scarring. Now it is well known that occlusion can regulate epidermal cytokine and growth factor production; changes in profibrotic and anti-fibrotic factors have been established. As a result, it is to be expected that moisturizers may improve the signs and symptoms of scars. As striae have been suggested to be anatomically similar to scars and as it is well established that paracrine signalling occurs in skin, it is expected that striae have similar SC issues. While one cannot exclude the effects of some of the ingredients used in the products, several studies are reported in this review that demonstrates that moisturization is a key component to reducing the clinical signs and symptoms of scars and striae. This is a good example of how knowledge of corneobiology leads to corneotherapies for these skin condition problems. The review is being written in memory of Professor Johann Wiechers who, before he died tragically in November 2011, performed two of the reported studies together with colleagues.

The role of the epidermis and the mechanism of action of occlusive dressings in scarring

The problem of cutaneous scarring has conventionally been approached as a pathology of the dermis. Multiple lines of evidence from the clinic, in vitro experiments, and in vivo animal and human studies, however, increasingly suggest that the epidermis plays a major role in the control of underlying dermal scar. Building on the demonstrated efficacy of silicone gel occlusion, in this paper we review the evidence for epidermal regulation of scar, and propose the novel hypothesis that dermal fibrosis is exquisitely linked to the inflammatory state of the epidermis, which in turn is linked to hydration state as a function of epidermal barrier function. In the spectrum of factors contributing to dermal scar, the epidermis and its downstream effectors offer promising new targets for the development of antiscar therapies.

The effects of topically applied silicone gel and its silver derivative on the prevention of hypertrophic scarring in two rabbit ear-scarring models

Topically applied silicone gel is an effective treatment in the management of hypertrophic scars. This early study of silicone gel predates other well-controlled scientific studies that demonstrate these findings. Our well-established rabbit ear scarring model creates 7 mm punch wounds down to the bare cartilage, including the removal of the perichondrium. In this study, we employ a new model that creates 10 mm punch wounds that leaves the perichondrium intact. Both the 7 mm and new 10 mm scar models were used to study the effectiveness of silicone gel and silicone gel silver respectively on hypertrophy and the inhibition of scar formation. All samples were harvested at post-wounding day 35 for histological analysis. Silicone gel significantly reduced scar area (p=0.005), scar elevation index (p=0.03), and epidermal area (p=0.016). Silicone gel silver significantly reduced scar elevation index (p=0.004). The new 10 mm scar model resulted in more hypertrophic scarring than the typical, 7 mm wound scar model (p=0.0001). In conclusion, silicone gel and its silver derivative are effective in preventing hypertrophic scarring and scar models that leave the perichondrium intact causes scars with more hypertrophy.

Epithelial regulation of mesenchymal tissue behavior

Fibroproliferative scars are an important clinical problem, and yet the mechanisms that regulate scar formation remain poorly understood. This study explored the hypothesis that the epithelium has a critical role in dictating scar formation, and that these interactions differ in skin and mucosa. Paired skin and vaginal mucosal wounds on New Zealand white (NZW) rabbits diverged significantly; the cutaneous epithelium exhibited a greater and prolonged response to injury when compared with the mucosa. Microarray analysis of the injured epithelium was performed, and numerous factors were identified that were more strongly upregulated in skin, including several proinflammatory cytokines and profibrotic growth factors. Analysis of the underlying mesenchymal tissue demonstrated a fibrotic response in the dermis of the skin but not the mucosal lamina propria, in the absence of a connective tissue injury. To determine if the proinflammatory factors produced by the epidermis may have a role in dermal fibrosis, an IL-1 receptor antagonist was administered locally to healing skin wounds. In the NZW rabbit model, blockade of IL-1 signaling was effective in preventing hypertrophic scar formation. These results support the idea that soluble factors produced by the epithelium in response to injury may influence fibroblast behavior and regulate scar formation in vivo.

Positional differences in the wound transcriptome of skin and oral mucosa

Background

When compared to skin, oral mucosal wounds heal rapidly and with reduced scar formation. Recent studies suggest that intrinsic differences in inflammation, growth factor production, levels of stem cells, and cellular proliferation capacity may underlie the exceptional healing that occurs in oral mucosa. The current study was designed to compare the transcriptomes of oral mucosal and skin wounds in order to identify critical differences in the healing response at these two sites using an unbiased approach.

Results

Using microarray analysis, we explored the differences in gene expression in skin and oral mucosal wound healing in a murine model of paired equivalent sized wounds. Samples were examined from days 0 to 10 and spanned all stages of the wound healing process. Using unwounded matched tissue as a control, filtering identified 1,479 probe sets in skin wounds yet only 502 probe sets in mucosal wounds that were significantly differentially expressed over time. Clusters of genes that showed similar patterns of expression were also identified in each wound type. Analysis of functionally related gene expression demonstrated dramatically different reactions to injury between skin and mucosal wounds. To explore whether site-specific differences might be derived from intrinsic differences in cellular responses at each site, we compared the response of isolated epithelial cells from skin and oral mucosa to a defined in vitro stimulus. When cytokine levels were measured, epithelial cells from skin produced significantly higher amounts of proinflammatory cytokines than cells from oral mucosa.

Conclusions

The results provide the first detailed molecular profile of the site-specific differences in the genetic response to injury in mucosa and skin, and suggest the divergent reactions to injury may derive from intrinsic differences in the cellular responses at each site.