Thermal injury model in the rabbit ear with quantifiable burn progression and hypertrophic scar

Blank Spots in the Map of Human Skin: The Challenge for Xenotransplantation

Most of the knowledge about human skin homeostasis, development, wound healing, and diseases has been accumulated from human skin biopsy analysis by transferring from animal models and using different culture systems. Human-to-mouse xenografting is one of the fundamental approaches that allows the skin to be studied in vivo and evaluate the ongoing physiological processes in real time. Humanized animals permit the actual techniques for tracing cell fate, clonal analysis, genetic modifications, and drug discovery that could never be employed in humans. This review recapitulates the novel facts about mouse skin self-renewing, regeneration, and pathology, raises issues regarding the gaps in our understanding of the same options in human skin, and postulates the challenges for human skin xenografting.

An Updated Review of Hypertrophic Scarring

Hypertrophic scarring (HTS) is an aberrant form of wound healing that is associated with excessive deposition of extracellular matrix and connective tissue at the site of injury. In this review article, we provide an overview of normal (acute) wound healing phases (hemostasis, inflammation, proliferation, and remodeling). We next discuss the dysregulated and/or impaired mechanisms in wound healing phases that are associated with HTS development. We next discuss the animal models of HTS and their limitations, and review the current and emerging treatments of HTS.

Advantages and Disadvantages of Using Small and Large Animals in Burn Research: Proceedings of the 2021 Research Special Interest Group

Multiple animal species and approaches have been used for modeling different aspects of burn care, with some strategies considered more appropriate or translatable than others. On April 15, 2021, the Research Special Interest Group of the American Burn Association held a virtual session as part of the agenda for the annual meeting. The session was set up as a pro/con debate on the use of small versus large animals for application to four important aspects of burn pathophysiology: burn healing/conversion; scarring; inhalation injury; and sepsis. For each of these topics, 2 experienced investigators (one each for small and large animal models) described the advantages and disadvantages of using these preclinical models. The use of swine as a large animal model was a common theme due to anatomic similarities with human skin. The exception to this was a well-defined ovine model of inhalation injury; both of these species have larger airways which allow for incorporation of clinical tools such as bronchoscopes. However, these models are expensive and demanding from labor and resource standpoints. Various strategies have been implemented to make the more inexpensive rodent models appropriate for answering specific questions of interest in burns. Moreover, modelling burn-sepsis in large animals has proven difficult. It was agreed that the use of both small and large animal models have merit for answering basic questions about the responses to burn injury. Expert opinion and the ensuing lively conversations are summarized herein, which we hope will help inform experimental design of future research.

Role of animal models in biomedical research: a review

The animal model deals with the species other than the human, as it can imitate the disease progression, its’ diagnosis as well as a treatment similar to human. Discovery of a drug and/or component, equipment, their toxicological studies, dose, side effects are in vivo studied for future use in humans considering its’ ethical issues. Here lies the importance of the animal model for its enormous use in biomedical research. Animal models have many facets that mimic various disease conditions in humans like systemic autoimmune diseases, rheumatoid arthritis, epilepsy, Alzheimer’s disease, cardiovascular diseases, Atherosclerosis, diabetes, etc., and many more. Besides, the model has tremendous importance in drug development, development of medical devices, tissue engineering, wound healing, and bone and cartilage regeneration studies, as a model in vascular surgeries as well as the model for vertebral disc regeneration surgery. Though, all the models have some advantages as well as challenges, but, present review has emphasized the importance of various small and large animal models in pharmaceutical drug development, transgenic animal models, models for medical device developments, studies for various human diseases, bone and cartilage regeneration model, diabetic and burn wound model as well as surgical models like vascular surgeries and surgeries for intervertebral disc degeneration considering all the ethical issues of that specific animal model. Despite, the process of using the animal model has facilitated researchers to carry out the researches that would have been impossible to accomplish in human considering the ethical prohibitions.

In Vivo Models for Hypertrophic Scars—A Systematic Review

Backgroundand Objectives: Hypertrophic scars following surgeries or burns present a serious concern for many patients because these scars not only lead to an aesthetical but also to a functional and psychological burden. Treatment of hypertrophic scars is challenging because despite various treatment options, a low level of evidence hinders preference of any specific treatment plan. To properly identify new therapeutic approaches, the use of in vivo models remains indispensable. A gold standard for hypertrophic scars has not been established to date. This review aims at giving a comprehensive overview of the available in vivo models. Materials and Methods: PubMed and CINAHL were queried for currently existing models. Results: Models with mice, rats, rabbits, pigs, guinea pigs and dogs are used in hypertrophic scar research. Rodent models provide the advantage of ready availability and low costs, but the number of scars per animal is limited due to their relatively small body surface, leading to a high number of test animals which should be avoided according to the 3Rs. Multiple scars per animal can be created in the guinea pig and rabbit ear model; but like other rodent models, these models exhibit low transferability to human conditions. Pig models show a good transferability, but are cost-intensive and require adequate housing facilities. Further, it is not clear if a currently available pig model can deliver clinical and histological features of human hypertrophic scars concurrently. Conclusions: None of the analyzed animal models can be clearly recommended as a standard model in hypertrophic scar research because the particular research question must be considered to elect a suitable model.

A Systematic Review Comparing Animal and Human Scarring Models

Introduction

A reproducible, standardised model for cutaneous scar tissue to assess therapeutics is crucial to the progress of the field. A systematic review was performed to critically evaluate scarring models in both animal and human research.

Method

All studies in which cutaneous scars are modelling in animals or humans were included. Models that were focused on the wound healing process or those in humans with scars from an existing injury were excluded. Ovid Medline^® was searched on 25 February 2019 to perform two near identical searches; one aimed at animals and the other aimed at humans. Two reviewers independently screened the titles and abstracts for study selection. Full texts of potentially suitable studies were then obtained for analysis.

Results

The animal kingdom search yielded 818 results, of which 71 were included in the review. Animals utilised included rabbits, mice, pigs, dogs and primates. Methods used for creating scar tissue included sharp excision, dermatome injury, thermal injury and injection of fibrotic substances. The search for scar assessment in humans yielded 287 results, of which 9 met the inclusion criteria. In all human studies, sharp incision was used to create scar tissue. Some studies focused on patients before or after elective surgery, including bilateral breast reduction, knee replacement or midline sternotomy.

Discussion

The rabbit ear scar model was the most popular tool for scar research, although pigs produce scar tissue which most closely resembles that of humans. Immunodeficient mouse models allow for in vivo engraftment and study of human scar tissue, however, there are limitations relating to the systemic response to these xenografts. Factors that determine the use of animals include cost of housing requirements, genetic traceability, and ethical concerns. In humans, surgical patients are often studied for scarring responses and outcomes, but reproducibility and patient factors that impact healing can limit interpretation. Human tissue use in vitro may serve as a good basis to rapidly screen and assess treatments prior to clinical use, with the advantage of reduced cost and setup requirements.

Comparison of Thermal Burn-Induced and Excisional-Induced Scarring in Animal Models: A Review of the Literature

Significance: Scar formation is a natural result of mammalian wound healing. In humans and other mammals, however, deep dermal wounds and thermal injuries often result in formation of hypertrophic scars, leading to substantial morbidity and lending great importance to development of therapeutic modalities for burn scars. Clinical Issues: Thus, preclinical burn wound models that adequately simulate processes underlying human burn-induced wound healing, particularly those processes leading to chronic inflammation and development of hypertrophic scars, are critical to developing further treatment paradigms for clinical use. Approach: In this study, we review literature describing various burn models, focusing on their characteristics and the functional readouts that lead to generation of useful data. We also briefly discuss recent work using human ex vivo skin culture as an alternative to animal models, as well as our own development of rabbit ear wound models for burn scars, and assess the pros and cons of these models compared to other models. Future Direction: Understanding of the strengths and weaknesses of preclinical burn wound models will enable choice of the most appropriate wound model to answer particular clinically relevant questions, furthering research aimed at treating burn scars.

Large animal models of thermal injury

Burn injury results in a triad of inter-related adaptive responses: a systemic inflammatory response, a stress response, and a consequent hypermetabolic state which supports the former two. These pathological responses extend beyond the site of injury to affect distant organs and influence long-term outcomes in the patient. Animal models have proven valuable in advancing our understanding of mechanisms underlying the multifactorial manifestations of burn injury. While rodent models have been unprecedented in providing insights into signaling pathways, metabolic responses, protein turnover, cellular and molecular changes; small animal models do not replicate hypermetabolism, hyperinflammation, and wound healing after a burn injury as seen in humans. Herein, we provide a concise review of preferred large animal models utilized to understand burn pathophysiology based on organ systems and associated dysfunction. Additionally, we present a detailed protocol of contact burn injury in the Yorkshire pig model with a focus on preoperative care, anesthesia, analgesia, wound excision and grafting, dressing application, and frequency of dressing changes.

The Effect of Topical Corticosteroid Time of Application on Fibroblast and Type III Collagen Expression in Oryctolagus cuniculus with Deep Dermal Burn Wound (As an Indicator for the Best Time to Start Topical Corticosteroid Application in Preventing Hypertrophic Scar)

Background: Hypertrophic scar is an abnormal scar that causes physical deteriorations, psychological problems, and aesthetic issues. An excessive number of fibroblasts and collagen III expressions are histopathology indicators for the hypertrophic scar. The role of topical corticosteroids in suppressing inflammation and hypergranulation had widely demonstrated in previous studies. However, there is no study related to the application of topical corticosteroids as prevention of hypertrophic scars from burn wound found. Hence, this study aimed to examine the evidence of the effects of corticosteroid topical in decreasing the number of fibroblasts and type III collagen expression and the best time to start its application in preventing hypertrophic scars. Methods: This randomized experimental post-test only study involved 54 deep dermal burn wounds on the ventral ear of female Oryctolagus cuniculus that distributed into three groups based on the healing phases. Each group consisted of treatments and controls. Corticosteroid topical application on the first treatment group (inflammatory phase group), the second group (proliferation phase group), and the third group (remodelling phase group) was started on day 3, on day 10, and day 21, respectively. Specimens taken on day 35. Haematoxylin-Eosin and Immunohistochemically staining performed to measure the number of fibroblasts and type III collagen and to observe the epithelization and inflammation process. Results: The number of fibroblasts significantly decreased in the second treatment group (p =0.001) and followed by the first group (p = 0.016), but no significant decrease found in the third group (p = 0.430). The type III collagen decreased significantly in the second treatment group (p = 0.000) and followed by the third group (p = 0.019), but no significant decrease found in the first group. There was no statistically different number of fibroblast and type III collagen discovered between the controls. Complete epithelization found in all groups. Also, no ongoing inflammation found in all groups.  Conclusion : Topical corticosteroids on deep dermal burn wound revealed to be effective in reducing the number of fibroblasts and type III collagen with no healing disruption. The proliferation phase found to be the best time to start the application of topical corticosteroids.

Recent Advances in Experimental Burn Models

Experimental burn models are essential tools for simulating human burn injuries and exploring the consequences of burns or new treatment strategies. Unlike clinical studies, experimental models allow a direct comparison of different aspects of burns under controlled conditions and thereby provide relevant information on the molecular mechanisms of tissue damage and wound healing, as well as potential therapeutic targets. While most comparative burn studies are performed in animal models, a few human or humanized models have been successfully employed to study local events at the injury site. However, the consensus between animal and human studies regarding the cellular and molecular nature of systemic inflammatory response syndrome (SIRS), scarring, and neovascularization is limited. The many interspecies differences prohibit the outcomes of animal model studies from being fully translated into the human system. Thus, the development of more targeted, individualized treatments for burn injuries remains a major challenge in this field. This review focuses on the latest progress in experimental burn models achieved since 2016, and summarizes the outcomes regarding potential methodological improvements, assessments of molecular responses to injury, and therapeutic advances.

Modeling of Old Scars: Histopathological, Biochemical and Thermal Analysis of the Scar Tissue Maturation

Simple Summary

Severe skin scars (i.e., hypertrophic and keloid) induce physical and emotional discomfort and functional disorders such as contractures and body part deformations. Scar’s response to treatment depends on “maturity”, which increases with time but is not merely proportional to it. When “fresh”, scars are relatively more treatable by conservative methods, while the treatment is only partially efficient. In contrast, surgery is a preferred approach for the older scars, but it is associated with a risk of the scar regrowth and worsening after excision if unrecognized immature scar tissue remains in the operated lesion. Therefore, to develop better treatment and diagnostics of scars, understanding of the scar maturation is essential. This requires biologically accurate experimental models of skin scarring. The current models only mimic the early stages of skin scar development. They are useful for testing new scar-preventing approaches while not addressing the problem of the older scars that exist for years. In our study, we demonstrate a new rabbit model of “old” scars and explore what happens to the scar tissue during maturation. We define measurable signs to delineate the scar development stages and discuss how this knowledge can improve scar diagnostics and treatment.

Abstract

Mature hypertrophic scars (HSs) remain a challenging clinical problem, particularly due to the absence of biologically relevant experimental models as a standard rabbit ear HS model only reflects an early stage of scarring. The current study aims to adapt this animal model for simulation of mature HS by validating the time of the scar stabilization using qualitative and quantitative criteria. The full-thickness skin and perichondrium excision wounds were created on the ventral side of the rabbit ears. The tissue samples were studied on post-operation days (PODs) 30, 60, 90 and 120. The histopathological examination and morphometry were applied in parallel with biochemical analysis of protein and glycosaminoglycans (GAGs) content and amino acid composition. The supramolecular organization of collagen was explored by differential scanning calorimetry. Four stages of the rabbit ear HS maturation were delineated and attributed with the histolomorphometrical and physicochemical parameters of the tissue. The experimental scars formed in 30 days but stabilized structurally and biochemically only on POD 90–120. This evidence-based model can be used for the studies and testing of new treatments of the mature HSs.

Active neutrophil responses counteract Candida albicans burn wound infection of ex vivo human skin explants

Burn wounds are highly susceptible sites for colonization and infection by bacteria and fungi. Large wound surface, impaired local immunity, and broad-spectrum antibiotic therapy support growth of opportunistic fungi such as Candida albicans, which may lead to invasive candidiasis. Currently, it remains unknown whether depressed host defenses or fungal virulence drive the progression of burn wound candidiasis. Here we established an ex vivo burn wound model, where wounds were inflicted by applying preheated soldering iron to human skin explants, resulting in highly reproducible deep second-degree burn wounds. Eschar removal by debridement allowed for deeper C. albicans penetration into the burned tissue associated with prominent filamentation. Active migration of resident tissue neutrophils towards the damaged tissue and release of pro-inflammatory cytokine IL-1β accompanied the burn. The neutrophil recruitment was further increased upon supplementation of the model with fresh immune cells. Wound area and depth decreased over time, indicating healing of the damaged tissue. Importantly, prominent neutrophil presence at the infected site correlated to the limited penetration of C. albicans into the burned tissue. Altogether, we established a reproducible burn wound model of candidiasis using ex vivo human skin explants, where immune responses actively control the progression of infection and promote tissue healing.

Imiquimod-induced skin inflammation is relieved by knockdown of sodium channel Nax

Na_x is an atypical sodium channel that mediates inflammatory pathways in pathological conditions of the skin. In this study, we developed a skin inflammation model in the rabbit ear through application of imiquimod (IMQ). Knockdown of Na_x using RNAi attenuated IMQ-induced skin inflammation, including skin erythema, scaling and papule formation. Histologic analysis showed that thickening and insufficient differentiation of the epidermis found in psoriasis-like skin were normalized by administration of Na_x -RNAi. Excessive infiltration of inflammatory cells found in inflammatory lesions, such as mast cells, eosinophils, neutrophils, T cells and macrophages, was reduced by Na_x -RNAi. Expression of S100A9, which is a downstream gene of Na_x and a mediator of inflammation, was decreased by Na_x -RNAi. Our results demonstrated that knockdown of Na_x ameliorated IMQ-induced psoriasis-like skin inflammation in vivo. Thus, targeting of Na_x may represent a potential therapeutic option for the treatment of psoriasis.

Nanotechnology-Based Medical Devices for the Treatment of Chronic Skin Lesions: From Research to the Clinic

Chronic wounds, such as pressure ulcers, diabetic ulcers, venous ulcers and arterial insufficiency ulcers, are lesions that fail to proceed through the normal healing process within a period of 12 weeks. The treatment of skin chronic wounds still represents a great challenge. Wound medical devices (MDs) range from conventional and advanced dressings, up to skin grafts, but none of these are generally recognized as a gold standard. Based on recent developments, this paper reviews nanotechnology-based medical devices intended as skin substitutes. In particular, nanofibrous scaffolds are promising platforms for wound healing, especially due to their similarity to the extracellular matrix (ECM) and their capability to promote cell adhesion and proliferation, and to restore skin integrity, when grafted into the wound site. Nanotechnology-based scaffolds are emphasized here. The discussion will be focused on the definition of critical quality attributes (chemical and physical characterization, stability, particle size, surface properties, release of nanoparticles from MDs, sterility and apyrogenicity), the preclinical evaluation (biocompatibility testing, alternative in vitro tests for irritation and sensitization, wound healing test and animal wound models), the clinical evaluation and the CE (European Conformity) marking of nanotechnology-based MDs.

Bioengineered Hybrid Collagen Scaffold Tethered with Silver-Catechin Nanocomposite Modulates Angiogenesis and TGF-β Toward Scarless Healing in Chronic Deep Second Degree Infected Burns

Management of burn wounds with diabetes and microbial infection is challenging in tissue engineering. The delayed wound healing further leads to scar formation in severe burn injury. Herein, a silver-catechin nanocomposite tethered collagen scaffold with angiogenic and antibacterial properties is developed to enable scarless healing in chronic wounds infected with Pseudomonas aeruginosa under diabetic conditions. Histological observations of the granulation tissues collected from an experimental rat model show characteristic structural organizations similar to normal skin, whereas the open wound and pristine collagen scaffold treated animals display elevated dermis with thick epidermal layer and lack of appendages. Epidermal thickness of the hybrid scaffold treated diabetic animals is lowered to 33 ± 2 µm compared to 90 ± 2 µm for pristine collagen scaffold treated groups. Further, the scar elevation index of 1.3 ± 0.1 estimated for the bioengineered scaffold treated diabetic animals is closer to the normal skin. Immunohistochemical analyses provide compelling evidence for the enhanced angiogenesis as well as downregulated transforming growth factor- β1 (TGF-β1) and upregulated TGF-β3 expressions in the hybrid scaffold treated animal groups. The insights from this study endorse the bioengineered collagen scaffolds for applications in tissue regeneration without scar in chronic burn wounds.

Liposome-encapsulated statins reduce hypertrophic scarring through topical application

Hypertrophic scar is an important clinical problem with limited therapeutic options. Aside from their roles as 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, statins have also been demonstrated to decrease scarring by reducing connective tissue growth factor (CTGF) expression. However, poor penetrative ability limits their utility as topical treatments for hypertrophic scar. Here, we aim to develop novel statin formulations using liposomes to enhance dermal penetrative ability and to evaluate their efficacy against formation of hypertrophic scar utilizing our validated rabbit ear hypertrophic scar model. Liposomal simvastatin or pravastatin were compounded using a novel, flexible liposomal formulation and applied topically to rabbit ear hypertrophic scars daily from postoperation day (POD) 14 until POD 25. Scar color, including erythema and melanin, was measured using reflectance spectrophotometry on POD 28, and scar tissue was harvested for evaluation of scar elevation index as well as gene and protein expression. Human foreskin fibroblasts were also treated with statin formulations and CCN2 expression was determined by quantitative PCR. Both simvastatin and pravastatin were efficiently encapsulated in liposomes, forming nanometer-scale particles possessing highly negative charges. Topical treatment with liposomal simvastatin and pravastatin at 6.5% concentration significantly reduced scar elevation index and decreased type I/III collagen content and myofibroblast persistence in the wound. The erythema/vascularity of scars was reduced by liposomal statin treatment, with concomitant decrease of CD31 expression as measured histologically. Expression levels of transcripts encoding CTGF, collagen I, and collagen III collagen in scar tissue were also decreased by liposomal pravastatin treatment, as were myofibroblast persistence and the type I/III collagen ratio as assessed by immunofluorescence and picrosirus red staining, respectively. Treatment of human foreskin fibroblasts with simvastatin or with liposome-encapsulated pravastatin resulted in decreased expression of transcript encoding CTGF. Overall, our novel statin formulations encapsulated in liposomes were successfully delivered through topical application, significantly reducing hypertrophic scarring in a rabbit ear model.

Effects of Fibroblast Growth Factor 2 on Burn Injury and Repair Process: Analysis Using a Refined Mouse Model

Background

Burn injury is one of the most debilitating traumas, which induces multiple organ dysfunctions, resulting in high levels of morbidity and mortality. Fibroblast growth factor 2 (FGF2) has been applied to burn injury, whose precise mechanisms underlying facilitating the healing have not been fully understood. Although various animal models have been developed in pigs, rabbits, rats, and mice, no mouse model that creates burns consistent in their extent and depth have not been developed. Here, we developed a mouse burn model, and investigated details of the burn process, and elucidated the mechanisms of FGF2 effects.

Methods

A device with an 8-mm metal probe and a temperature controller was developed, which controls the temperature of the probe. Using the device, 1 or 2 of full-thickness burn injuries were generated on the back under catagen/telogen of 6-month-old C57BL/6 male mice. After 24 hours, FGF2 or phosphate-buffered saline was injected into the injured region, and at days 3, 5, and 7, histological and immunohistochemical analysis was performed to observe the injury and repair process.

Results

The device constantly generated a mouse full-thickness burn injury. The repair was initiated on the bottom of the burn as well as the margin. Local treatment with FGF2 displayed higher levels of immunostaining for both CD31+ and alpha-smooth muscle actin.

Conclusions

The device we developed is useful to generate a mouse burn injury model. FGF2 facilitates tissue repair with an increased number of both CD31+ and αSMA+ cells.

Silica microsphere–resorcinol composite embedded collagen scaffolds impart scar-less healing of chronic infected burns in type-I diabetic and non-diabetic rats

Biocompatible hybrid collagen scaffolds embedded with a silica–resorcinol composite promote scar-less wound healing in chronically infected deep second-degree burns.

Experimental models for cutaneous hypertrophic scar research

Human skin wound repair may result in various outcomes with most of them leading to scar formation. Commonly seen in many cutaneous wound healing cases, hypertrophic scars are considered as phenotypes of abnormal wound repair. To prevent the formation of hypertrophic scars, efforts have been made to understand the mechanism of scarring following wound closure. Numerous in vivo and in vitro models have been created to facilitate investigations into cutaneous scarring and the development of antiscarring treatments. To select the best model for a specific study, background knowledge of the current models of hypertrophic scars is necessary. In this review, we describe in vivo and in vitro models for studying hypertrophic scars, as well as the distinct characteristics of these models. The choice of models for a specific study should be based on the characteristics of the model and the goal of the study. In general, in vivo animal models are often used in phenotypical scar formation analysis, development of antiscarring treatment, and functional analyses of individual genes. In contrast, in vitro models are chosen to pathway identification during scar formation as well as in high-throughput analysis in drug development. Besides helping investigators choose the best scarring model for their research, the goal of this review is to provide knowledge for improving the existing models and development of new models. These will contribute to the progress of scarring studies.

Developing a Simple Burn Model in Rats of Different Ages

This article describes a simple and safe model of partial and full thickness burn injury in rats of different ages, which will be essential in our future burn research to explore the age-related mechanism of wound repair and new therapies for burn injuries. A self-made metal column, which was heated in a boiling water bath, was applied for different time periods to the lower back of rats of different ages in burn creation. Wounds were observed visibly at different time points postburn. Biopsies were obtained and examined at 72-hour postburn to determine the depth of burns. The contact durations producing the desired depth of injury in the rat model under constant temperature and pressure were: 3 seconds (deep second degree) and 5 seconds (third degree) in 1-month-old rats; 3 seconds (superficial second degree), 5 seconds (deep second degree), and 7-9 seconds (third degree) in 2-month-old rats; 3-5 seconds (superficial second degree), 7-9 seconds (deep second degree), and 11-13 seconds (third degree) in 12- and 18-month-old rats. This reliable and reproducible experimental model produces consistent burn injuries in rats of different ages by regulating the contact durations, which will help us to understand the underlying pathophysiology of burn injuries and develop novel therapeutic modalities for burn patients of different ages.

Akermanite bioceramic enhances wound healing with accelerated reepithelialization by promoting proliferation, migration, and stemness of epidermal cells

Reepithelialization is an important step of wound healing, which is mainly completed by proliferation and migration of epidermal cells. Akermanite is a Ca-, Mg-, and Si-containing bioceramic. This study evaluated the effects of Akermanite on wound healing and investigated the mechanisms. Using scald burn mice models, we demonstrated that local Akermanite treatment significantly accelerated wound healing by increasing reepithelialization and the stemness of epidermal cells. Epidermal cells were cultured in medium containing Akermanite extracts to explore the cellular mechanism of reepithelialization. Akermanite promoted the cell proliferation and migration, maintaining more cells in the S and G₂ /M phases of the cell cycle. An additional study showed that Akermanite enhanced the expressions of integrinβ1, Lgr4, Lgr5, and Lgr6, which are specific molecular markers of epidermal stem cells, accompanied by the activation of the Wnt/β-catenin pathway. These results suggested that Akermanite accelerated reepithelialization by increasing the proliferation, migration, and stemness of epidermal cells in a manner related to the Wnt/β-catenin pathway, which might contribute, at least partially, to accelerated wound healing by Akermanite therapy.