Molecular Insights Into the Effects of PLLA-SCA on Gene Expression and Collagen Synthesis in Human 3D Skin Models Containing Macrophages.

Injectable poly-L-lactic acid (PLLA-SCA) is used for the correction of shallow to deep nasolabial fold contour deficiencies, cheek wrinkles, and other facial wrinkles. In contrast to hyaluronan (HA) fillers, PLLA-SCA has a biostimulatory effect by activating resident fibroblasts to produce collagen, but the mechanisms are not known in detail at the molecular level. Therefore, our aim was to investigate the molecular effects of PLLA-SCA in a comprehensive in vitro study. Since PLLA-SCA-dependent collagen production in fibroblasts depends on the interaction with macrophages, we generated novel macrophage-containing 3D skin models. According to the clinical application, PLLA-SCA was injected once into the dermal equivalent of the 3D skin model. Histological analysis showed a significant increase in epidermal thickness in these models after 5 and 14 days. Gene expression profiling revealed an upregulation of integrins and laminins (e.g., LAMA3, ITGA6), which are essential components of the dermal-epidermal junction. In addition, we found an upregulation of cytokines and chemokines (TGFB2, CXCL6, IL1B) at day 14 after PLLA-SCA injection. Interestingly, immunohistochemical analyses exhibited a significantly stimulated collagen I production in our models. These effects might be attributed, at least in part, to the upregulation of IL1B and subsequently CXCL6, which stimulates collagen I synthesis in human dermal fibroblasts as we could demonstrate. Taken together, our data provide for the first time molecular insights into the biostimulatory effects of PLLA-SCA on collagen I production in novel human 3D skin models comprising macrophages. J Drugs Dermatol. 2024;23(4):7791.    doi:10.36849/JDD.7791.

Pathological mutations reveal the key role of the cytosolic iRhom2 N-terminus for phosphorylation-independent 14-3-3 interaction and ADAM17 binding, stability, and activity.

The protease ADAM17 plays an important role in inflammation and cancer and is regulated by iRhom2. Mutations in the cytosolic N-terminus of human iRhom2 cause tylosis with oesophageal cancer (TOC). In mice, partial deletion of the N-terminus results in a curly hair phenotype (cub). These pathological consequences are consistent with our findings that iRhom2 is highly expressed in keratinocytes and in oesophageal cancer. Cub and TOC are associated with hyperactivation of ADAM17-dependent EGFR signalling. However, the underlying molecular mechanisms are not understood. We have identified a non-canonical, phosphorylation-independent 14-3-3 interaction site that encompasses all known TOC mutations. Disruption of this site dysregulates ADAM17 activity. The larger cub deletion also includes the TOC site and thus also dysregulated ADAM17 activity. The cub deletion, but not the TOC mutation, also causes severe reductions in stimulated shedding, binding, and stability of ADAM17, demonstrating the presence of additional regulatory sites in the N-terminus of iRhom2. Overall, this study contrasts the TOC and cub mutations, illustrates their different molecular consequences, and reveals important key functions of the iRhom2 N-terminus in regulating ADAM17.

Understanding the impact of risankizumab on keratinocyte-derived IL-23A in a novel organotypic 3D skin model containing IL-23A responsive and IL-17A producing γδ-T-cells.

PURPOSE: To study the effects of the anti-IL-23A antibody risankizumab on the IL-36γ/IL-23A/IL-17A signalling cascade we used a newly developed 3D skin model consisting of primary human keratinocytes, fibroblasts and γδ-T-cells. METHODS: In this in vitro study we developed new full-thickness 3D skin models containing normal human epidermal keratinocytes (NHEK), normal human dermal fibroblasts (NHDF) and IL-23A responsive and IL-17A producing γδ-T-cells. The effects of IL-36γ stimulation with and without risankizumab treatment on IL-23A and IL-17A expression were examined at the RNA and protein levels. RESULTS: In preliminary monolayer experiments stimulation of γδ-T-cells with IL-23A promoted the IL-17A expression that was inhibited after risankizumab treatment. Using 3D skin models containing γδ-T-cells, we found that stimulation with IL-36γ significantly increased not only IL-23A but also IL-17A expression. These effects were inhibited by concomitant treatment with risankizumab. CONCLUSIONS: Our results showed that blockade of IL-23A has inhibitory effects on the IL-36γ/IL-23A feedforward loop. Our newly developed 3D skin model containing IL-23A responsive and IL-17A producing γδ-T-cells enables molecular analysis of targeted therapies aimed at the IL-36γ/IL-23A/IL-17A signalling cascade in psoriasis.

Macrophage-like rapid uptake and toxicity of tattoo ink in human monocytes.

Macrophages play a critical role for the persistence of tattoo ink in human skin. However, a comparison to other skin-resident and blood circulating immune cells and a profound analysis of REACH-compliant tattoo ink are unmet medical needs. We hence characterized the size distribution of ink particles using physicochemical methods. We studied the uptake of tattoo ink by key human skin cells and blood-derived immune cells using optical and electron microscopy as well as flow cytometry. Scanning electron microscopy of ink revealed its crystalline structure, and a tendency towards aggregations was indicated by size changes upon diluting it. Flow cytometric analyses of skin and immune cells after incubation with tattoo ink demonstrated an increase in cellular granularity upon uptake and red ink additionally evoked fluorescent signals. Human macrophages were most potent in internalizing ink in full thickness 3D skin models. Macrophage cultures demonstrated that the ink did not lead to elevated inflammatory mediators, and showed no indications for toxicity, even after nice days. Strikingly, monocytes were most efficient in ink uptake, but displayed reduced viability, whereas granulocytes and lymphocytes showed only temporary ink uptake with flow cytometric signals declining after 1 day. Mechanistic studies on ink retention by corticosteroids or dexpanthenol in macrophage cultures demonstrated that these compounds do not lead to ink excretion, but even slightly increase the ink load in macrophages. The highly motile monocytes, precursors of macrophages, may play an underrated role for tattoo ink translocation from dermal blood vessels into internal organs.

Macrophage migration inhibitory factor (MIF) and its homolog D-dopachrome tautomerase (D-DT) are significant promotors of UVB- but not chemically induced non-melanoma skin cancer.

Non-melanoma skin cancer (NMSC) is the most common cancer in Caucasians worldwide. We investigated the pathophysiological role of MIF and its homolog D-DT in UVB- and chemically induced NMSC using Mif-/-, D-dt-/- and Mif-/-/D-dt-/- mice on a hairless SKH1 background. Knockout of both cytokines showed similar attenuating effects on inflammation after acute UVB irradiation and tumor formation during chronic UVB irradiation, without additive protective effects noted in double knockout mice, indicating that both cytokines activate a similar signaling threshold. In contrast, genetic deletion of Mif and D-dt had no major effects on chemically induced skin tumors. To get insight into the contributing mechanisms, we used an in vitro 3D skin model with incorporated macrophages. Application of recombinant MIF and D-DT led to an accumulation of macrophages within the epidermal part that could be reversed by selective inhibitors of MIF and D-DT pathways. In summary, our data indicate that MIF and D-DT contribute to the development and progression of UVB- but not chemically induced NMSC, a role at least partially accounted by effects of both cytokines on epidermal macrophage accumulation. These data highlight that MIF and D-DT are both potential therapeutic targets for the prevention of photocarcinogenesis but not chemical carcinogenesis.

Post-Treatment of Micro-Needling with a Dexpanthenol-Containing Ointment Accelerates Epidermal Wound Healing in Human 3D Skin Models.

Purpose: In vitro study on the molecular effects of post-treatment after micro-needling applications with a dexpanthenol-containing ointment (DCO) using 3D skin models. Patients and Methods: In this in vitro study, full-thickness human 3D skin models were treated with a micro-needling device according to its clinical application. For post-treatment, some of the models were additionally treated with a dexpanthenol-containing ointment (DCO). Histological samples were taken at 0, 24 and 48 hours. Gene expression analysis was performed after 24 hours. Results: Histological examination showed that DCO post-treated 3D skin models revealed a completed wound closure 24 hours after the micro-needling procedure. In contrast, DCO-untreated models still clearly exhibited the micro-needling lesions after the same period of time. After 48 hours, all models revealed a completed wound healing. In skin models that received micro-needling but no post-treatment with DCO, microarray analysis identified an upregulation of proinflammatory cytokines and chemokines and a downregulation of skin barrier and differentiation markers. In contrast, post-treatment with DCO leads to accelerated wound healing without affecting the initial inflammatory response caused by micro-needling, which leads to the subsequent collagen expression. This data was supported by qRT-PCR analyses. Conclusion: Post-treatment with DCO accelerates epidermal wound healing after micro-needling of 3D skin models without impairing the immunostimulatory properties of micro-needling. These findings can help to optimise the aftercare routine after micro-needling procedures and to shorten the downtime for the patient after treatment.

Therapy of pathological scars.

A scar develops following the appearance of a deep tissue defect as part of the physiological wound healing process. The initial inflammatory response is followed by proliferation of connective tissue cells, which form fibrosis as a final tissue substitute. Disorders can occur at all stages of the process and are most commonly manifested as impaired wound healing or the formation of atrophic and hypertrophic scars or keloids. The focus of this article is on the treatment of pathologic scars, which are an indication for therapy due to functional limitations, complaints, and stigmatization, among other reasons. Conservative medical, physical, surgical and laser therapeutic approaches are pursued. The basis for this is an understanding of the pathophysiological mechanisms and factors influencing the choice of therapy, as well as an interdisciplinary and interprofessional therapeutic approach.

S2k guideline: Laser therapy of the skin.

This guideline aims to improve the efficiency and safety of lasers and optical radiation sources with similar effects (especially IPL). Laser therapy of skin lesions with an increased amount of melanocytes should be performed with caution. Laser treatment of pigmented melanocytic nevi is not recommended. The guideline contains recommendations regarding the treatment of lentigines and café-au-lait spots, non-pigmented dermal nevi, Becker nevus, nevus of Ota/Hori/Ito and melasma. Further recommendations focus on the treatment of skin lesions without an increased amount of melanocytes (ephelides, postinflammatory hyperpigmentation including berloque dermatitis, seborrheic keratoses, traumatic/decorative tattoos and metallic deposits), hypopigmentation (vitiligo), benign non-pigmented neoplasms (fibrous papule of the nose, nevus sebaceus, epidermal nevus, neurofibroma, sebaceous gland hyperplasia, syringoma, xanthelasma palpebrarum), inflammatory dermatoses (acne papulopustulosa/conglobata, acne inversa, granuloma faciale, lichen sclerosus, lupus erythematosus, psoriasis vulgaris, rosacea, rhinophyma), wrinkles/dermatochalasis/striae, hypertrichosis, scars (atrophic, hypertrophic; keloids, burn/scald scars), laser-assisted skin healing, onychomycosis, precancerous lesions and malignant tumors (actinic keratoses/field cancerization, cheilitis actinica, basal cell carcinoma), vascular skin lesions (angiokeratoma, angioma, hemangioma, malformation, spider veins, granuloma telangiectaticum (pyogenic granuloma), rubeosis (erythrosis interfollicularis colli, ulerythema ophryogenes), nevus flammeus, telangiectasias and Osler's disease (hereditary hemorrhagic telangiectasia) and viral skin lesions (condylomata acuminata, mollusca contagiosa, verrucae planae juveniles/vulgares/ verrucae palmares et plantares).

Innate immune activation as cofactor in pemphigus disease manifestation.

Molecular mechanisms underlying auto-antibody-induced acantholysis in pemphigus vulgaris are subject of current research to date. To decipher the discrepancy between ubiquitous antibody binding to the epidermal desmosomes, but discontinuous disease manifestation, we were able to identify Ultraviolet A (UVA) as a cofactor for acantholysis. UVA induces interleukin (IL)-1 secretion in keratinocytes, mirroring innate immune system activation. In an in vitro keratinocyte dissociation assay increased fragmentation was observed when UVA was added to anti-Desmoglein 3 Immunoglobulins (anti-Dsg3 IgG). These results were confirmed in skin explants where UVA enhanced anti-Dsg3-mediated loss of epidermal adhesion. The UVA-mediated effect was blocked in vitro by the pan-caspase-inhibitor zVAD-fmk. Thus, we introduce UVA as a caspase-dependent exogenous cofactor for acantholysis which suggests that local innate immune responses largely contribute to overt clinical blister formation upon autoantibody binding to epidermal cells in pemphigus vulgaris.

MMP-3 plays a major role in calcium pantothenate-promoted wound healing after fractional ablative laser treatment.

Ablative fractional laser treatment leads to a loss of matrix metalloproteinase-3 (MMP-3) expression; therefore, in the present in vitro study, we addressed the role of MMP-3 and its regulation by calcium pantothenate in wound healing processes at the molecular level. Utilizing confocal laser microscopy, we investigated MMP-3 protein expression in fractional ablative CO2 laser-irradiated skin models. In addition, we established full-thickness 3D skin models using fibroblasts and keratinocytes with a MMP-3 knockdown that were irradiated with a fractional ablative Er:YAG laser to set superficial injuries with standardized dimensions and minimal thermal damage to the surrounding tissue. We revealed an upregulation of MMP-3 protein expression in laser-irradiated skin models receiving aftercare treatment with calcium pantothenate. Skin models with MMP-3 knockdown exhibited a slower wound closure after laser treatment compared to controls. Gene expression profiling detected an MMP-3 knockdown-dependent upregulation of cytokines and chemokines (e.g. IL-36B, CXCL17, IL-37, CXCL5), antimicrobial peptides (e.g., S100A7, S100A12), epidermal crosslinking enzymes (TGM5), and differentiation markers (e.g., LOR, KRT1, FLG2). We also detected a downregulation of cathepsin V and MMP-10, both of which play a prominent role in wound healing processes. After fractional ablative laser injury, an aftercare treatment with calcium pantothenate accelerated wound closure in MMP-3 expressing models faster than in MMP-3 knockdown models. Our data substantiate a major role of MMP-3 in wound healing processes after ablative laser treatments. For the first time, we could show that calcium pantothenate exerts its wound healing-promoting effects at least partly via MMP-3.

Management of patients with seasonal allergic rhinitis: Diagnostic consideration of sensitization to non-frequent pollen allergens.

BACKGROUND: Diagnosis of pollen allergies is mainly based on test allergens for skin prick testing. In the minimum battery of test inhalant allergens recommended by the Global Allergy and Asthma European Network 10 pollen allergens are included. Complementary other pollen allergens may need to be considered; however, respective awareness may not always be granted. Furthermore, at least in Germany, the situation may be even more complicated by the fact that test allergens need regulatory approval. A decline in commercially available test allergens may result in a diagnostic gap regarding patients with non-frequent allergies. How many patients with non-frequent pollen allergies would be affected by this gap? The data presented here partly answer this question. METHODS: The study consisted of a descriptive and an analytical part. In the descriptive part, sensitization to frequent pollen allergens (alder, hazel, birch, sweet grasses; according to the German Therapy Allergen Ordinance) and to respective non-frequent pollen allergens (cypress, Japanese cedar, ash, plane tree, olive, Bermuda grass, wall pellitory, plantain, goosefoot, mugwort, ragweed, and saltwort) was measured in adult patients with physician-diagnosed allergic rhinitis from two German federal states, namely North-Rhine Westphalia (n = 360) and Bavaria (n = 339), using skin prick testing and/or ISAC technology. Furthermore, respective regional pollen data were assessed. In the analytical part, sensitization data were correlated with each other and with anamnestic data on symptom periods. RESULTS: Sensitization to frequent pollen allergens ranged from 45% (sIgE to Aln g 1/Alder, NRW) to 72% (prick test reactivity to birch, NRW). Sensitization to non-frequent pollen allergens ranged from 0% (sIgE to Amb a 1/ragweed, NRW) to 41% (prick test reactivity to olive, Bavaria). Sensitization data partly correlated with each other and in connection with symptom periods showed a partly similar seasonal pattern as pollen data. CONCLUSIONS: Sensitization to non-frequent pollen allergens have to be considered when examining patients with respective seasonal symptoms, and test (and respective therapy) allergens for non-frequent pollen allergies need to be available. Further prerequisites for adequate patient management would be a nationwide pollen monitoring system giving continuous pollen data and a systematic sensitization monitoring at patient level.

Biological Effects of Hyaluronic Acid-Based Dermal Fillers and Laser Therapy on Human Skin Models.

Injection of dermal fillers is one of the most frequently performed aesthetic procedures. The aim of the present study was to investigate the biological effects of different stabilized hyaluronan (HA) and poly-l-lactic acid fillers with and without subsequent additional fractional laser co-treatment on skin morphology and gene expression. Intradermal injection resulted in a significant enhancement of epidermal thickness detected by histological analysis. Combining HA fillers with ablative fractional CO2- or Er:YAG laser irradiation enhanced this effect. Gene expression profiling revealed an upregulation of modulators of tissue remodeling (eg TIMP3, SERPIN E1) and collagens (COL11A1). On the other hand, we detected a downregulation of differentiation markers (eg FLG, LOR, KRT1) and proinflammatory cytokines (eg IL-36, IL-1β). Interestingly, HA-based fillers revealed a specific upregulation pattern of chemokines such as CXCL5 andCCL20 suggesting a secondary effect of these fillers on the immune cells of the skin, especially monocytes and macrophages. Taken together, our data show enhancing effects of dermal fillers on epidermal thickness and prove the proliferating effects of these products on epidermal cells on the molecular level. Moreover, our findings reveal synergistic effects of fractional ablative laser treatment and HA dermal filler injection suggesting a combination of both treatments. J Drugs Dermatol. 2020;19(9):897-899. doi:10.36849/JDD.2020.4856.

Inter-α-Trypsin Inhibitor Heavy Chain 5 (ITIH5) Is a Natural Stabilizer of Hyaluronan That Modulates Biological Processes in the Skin.

INTRODUCTION: Hyaluronan (HA) is a major component of the skin that exerts a variety of biological functions. Inter-α-trypsin inhibitor heavy chain (ITIH) proteins comprise a family of hyaladherins of which ITIH5 has recently been described in skin, where it plays a functional role in skin morphology and inflammatory skin diseases including allergic contact dermatitis (ACD). OBJECTIVE: The current study focused on the ITIH5-HA interaction and its potential clinical and functional impact in extracellular matrix (ECM) stabilization. METHODS: Studying the molecular effects of ITIH5 in skin, we established skin models comprising murine skin cells of Itih5 knockout mice and corresponding wild-type controls. In addition, human dermal fibroblasts with an ITIH5 knockdown as well as a murine recombinant Itih5 protein were established to examine the interaction between ITIH5 and HA using in vitro adhesion and HA degradation assays. To understand more precisely the role of ITIH5 in inflammatory skin diseases such as ACD, we generated ITIH5 knockout cells of the KeratinoSens® cell line. RESULTS: Using murine skin models, ITIH5 knockdown fibroblasts, and a reactive oxygen species (ROS)-mediated HA degradation assay, we proved that ITIH5 binds to HA, thereby acting as a stabilizer of HA. Moreover, microarray profiling revealed the impact of ITIH5 on biological processes such as skin development and ECM homeostasis. Performing the in vitro KeratinoSens skin sensitization assay, we detected that ITIH5 decreases the sensitizing potential of moderate and strong contact sensitizers. CONCLUSION: Taken together, our experiments revealed that ITIH5 forms complexes with HA, thereby on the one hand stabilizing HA and facilitating the formation of ECM structures and on the other hand modulating inflammatory responses.

Dexpanthenol in Wound Healing after Medical and Cosmetic Interventions (Postprocedure Wound Healing).

With the availability of new technologies, the number of subjects undergoing medical and cosmetic interventions is increasing. Many procedures (e.g., ablative fractional laser treatment) resulting in superficial/minor wounds require appropriate aftercare to prevent complications in wound healing and poor cosmetic outcome. We review the published evidence of the usefulness of topical dexpanthenol in postprocedure wound healing and the associated mechanisms of action at the molecular level. A search in the PubMed and Embase databases was performed to query the terms dexpanthenol, panthenol, superficial wound, minor wound, wound healing, skin repair, and postprocedure. Search results were categorized as clinical trials and in vitro studies. In vitro and clinical studies provided evidence that topically applied dexpanthenol promotes superficial and postprocedure wound healing. Latest findings confirmed that dexpanthenol upregulates genes that are critical for the healing process. The gene expression data are of clinical relevance as evidenced by prospective clinical studies indicating that topical dexpanthenol accelerates wound healing with rapid re-epithelialization and restoration of skin barrier function following skin injury. It can therefore be inferred that topical dexpanthenol represents an appropriate and state-of-the-art treatment option for superficial postprocedure wounds, especially when applied early after the superficial skin damage.

Optimal Support of Wound Healing: New Insights.

BACKGROUND: The ultimate goal of wound healing following minor injury is to form a tissue regenerate that has functionality and visual appearance as close to the original skin as possible. The body's physiological response to any wound is traditionally characterised by three distinct steps: inflammation, proliferation and remodelling. SUMMARY: New insights suggest that the three phases overlap (and even occur in parallel) in both time and space in the wound, necessitating a clinical approach that targets each stage simultaneously to ensure rapid repair and wound closure without further complications. Ingredients that exhibit activity across each of the three phases, such as dexpanthenol, are of value in the context of minor wound care and scar management. Key Messages: In addition to treatment and ingredient selection, it is also important to consider broader clinical best practices and self-care options that can be used to optimise the management of minor wounds. An individualised approach that can account for a patient's unique requirements and preferences is critical in achieving effective wound recovery.

Bifonazole Exerts Anti-Inflammatory Effects in Human Three-Dimensional Skin Equivalents after UVB or Histamine Challenge.

BACKGROUND: In addition to its role as a broad-spectrum imidazole antifungal drug, data from animal models as well as human clinical trials also demonstrated an anti-inflammatory efficacy of bifonazole (BFZ). In the histamine wheal test and after UV radiation, BFZ showed antiphlogistic effects that were comparable to those of hydrocortisone. However, the underlying molecular mechanisms of the anti-inflam-matory properties of BFZ are poorly understood. METHODS: Performing an in vitro study we used full-thickness three-dimensional (3D) skin models containing macrophages as mediators of inflammation. We conducted two sets of experiments. In a first set we exposed our models to UVB irradiation to provoke an inflammation. A second approach used the addition of histamine into the culture medium. In both approaches, models were treated topically with a BFZ-containing ointment or a placebo ointment for 24 h, and then the effects were examined histologically as well as with microarray and quantitative real-time PCR analyses. RESULTS: Histological examination showed that the BFZ-containing ointment reconstituted UVB- and histamine-mediated disorders within the skin models. Performing gene expression profiling in models that were treated with the BFZ-containing ointment after UVB irradiation, we detected an upregu-lation of differentiation markers (fillagrin, loricrin, and keratin 1), antimicrobial peptides (DEFB103A), and members of the cytochrome P450 family (CYP1A1 and CYP1B1) as well as a downregulation of genes that are involved in immune response (CCL22, CXCL12, CCL7, IRF1, ICAM1, TLR3, and RARRES3) and matrix metalloproteinases (MMP12 and MMP7). Models that were treated with the BFZ-containing ointment after histamine application showed an upregulation of members of the cytochrome P450 family (CAP1A1, CYP1B1, and CYP24A1) and a downregulation of immune response-associated genes (CXCL6, CXCL12, CCL8, IL6, and IL32). CONCLUSION: We present the first in vitro study showing anti-inflammatory effects of BFZ in human 3D skin models. To our knowledge, this is the first time that these effects could be translated from human clinical trials into an in vitro test system, allowing a more detailed examination of molecular mechanisms that were regulated by BFZ.

Novel Human Full-Thickness Three-Dimensional Nonkeratinized Mucous Membrane Model for Pharmacological Studies in Wound Healing.

INTRODUCTION: Efforts are increasingly aiming to develop in vitro models that can provide effective alternatives to in vivo experiments. The main aim of this study was the establishment of an in vitro model of the nonkeratinized mucous membrane that can be used as a standardized tool to evaluate biological and therapeutic effects of pharmaceuticals for mucosal wound healing. METHODS: We established a full-thickness in vitro model of the nonkeratinized mucous membrane. While histological examination was performed to assess morphological characteristics, we utilized gene expression profiling using microarray and qRT-PCR analyses to identify molecular effects of treatment with a dexpanthenol-containing ointment after laser wounding. RESULTS: Performing histological and immunofluorescence analyses we proved that our model mimics the two distinctive layers of the mucous membrane - the stratified squamous epithelium and the lamina propria. We used this model to investigate molecular effects of a dexpanthenol-containing ointment that is commonly used for the wound treatment of mucous membranes. For that purpose, our model exhibits a unique feature in that dexpanthenol and proliferation-enhancing additives that may interfere with our studies are not required for the maintenance of the model culture. After setting standardized lesions with a nonsequential fractional ultrapulsed CO2 laser, topical treatment with the dexpanthenol-containing ointment enhanced wound closure in the model compared to placebo and untreated controls. Furthermore, microarray analysis revealed that the treatment of the laser-wounded model with the dexpanthenol-containing ointment evoked an upregulated expression of various genes related to accelerated wound healing. CONCLUSION: Overall, we verified that this novel mucous membrane model can be utilized in future to monitor ex vivo effects of various topical therapies on mucosa morphology, physiology, and gene expression. Our findings confirm the potential of the model as an in vitro tool for the replacement of pharmacological in vivo studies regarding mucosal wound healing.