New insights on keloids, hypertrophic scars, and striae

Stem cell-based therapy for fibrotic diseases: mechanisms and pathways

Fibrosis is a pathological process, that could result in permanent scarring and impairment of the physiological function of the affected organ; this condition which is categorized under the term organ failure could affect various organs in different situations. The involvement of the major organs, such as the lungs, liver, kidney, heart, and skin, is associated with a high rate of morbidity and mortality across the world. Fibrotic disorders encompass a broad range of complications and could be traced to various illnesses and impairments; these could range from simple skin scars with beauty issues to severe rheumatologic or inflammatory disorders such as systemic sclerosis as well as idiopathic pulmonary fibrosis. Besides, the overactivation of immune responses during any inflammatory condition causing tissue damage could contribute to the pathogenic fibrotic events accompanying the healing response; for instance, the inflammation resulting from tissue engraftment could cause the formation of fibrotic scars in the grafted tissue, even in cases where the immune system deals with hard to clear infections, fibrotic scars could follow and cause severe adverse effects. A good example of such a complication is post-Covid19 lung fibrosis which could impair the life of the affected individuals with extensive lung involvement. However, effective therapies that halt or slow down the progression of fibrosis are missing in the current clinical settings. Considering the immunomodulatory and regenerative potential of distinct stem cell types, their application as an anti-fibrotic agent, capable of attenuating tissue fibrosis has been investigated by many researchers. Although the majority of the studies addressing the anti-fibrotic effects of stem cells indicated their potent capabilities, the underlying mechanisms, and pathways by which these cells could impact fibrotic processes remain poorly understood. Here, we first, review the properties of various stem cell types utilized so far as anti-fibrotic treatments and discuss the challenges and limitations associated with their applications in clinical settings; then, we will summarize the general and organ-specific mechanisms and pathways contributing to tissue fibrosis; finally, we will describe the mechanisms and pathways considered to be employed by distinct stem cell types for exerting anti-fibrotic events.

The currrent landscape of antifibrotic therapy across different organs: A systematic approach

Fibrosis is a common pathological process that can affect virtually all the organs, but there are hardly any effective therapeutic options. This has led to an intense search for antifibrotic therapies over the last decades, with a great number of clinical assays currently underway. We have systematically reviewed all current and recently finished clinical trials involved in the development of new antifibrotic drugs, and the preclinical studies analyzing the relevance of each of these pharmacological strategies in fibrotic processes affecting tissues beyond those being clinically studied. We analyze and discuss this information with the aim of determining the most promising options and the feasibility of extending their therapeutic value as antifibrotic agents to other fibrotic conditions.

Ubiquitin-specific peptidase 11 promotes development of keloid derived fibroblasts by de-ubiquitinating TGF-β receptorII

BACKGROUND

Keloid scars occur as a result of abnormal wound healing caused by trauma or inflammation of the skin. The progression of keloids is dependent on genetic and environmental influences. The incidence is more prevalent in people with darker skin tones (African, Asian and Hispanic origin). Studies have demonstrated that transforming growth factor (TGF) β/Smad signalling has an essential function in keloid as well as that USP11 could modulate the activation of TGFβ/Smad signalling and impact the progression of the fibrotic disease. Nonetheless, the potential mechanisms of USP11 in keloid were still unclear. The authors postulated that USP11 up-regulates and augments the ability of proliferation, invasion, migration and collagen deposition of keloid-derived fibroblasts (KFBs) through deubiquitinating TGF-β receptor II (TβRII).

METHODS

Fibroblast cells were isolated from keloid scars in vitro. Lentivirus infection was utilized to knockdown and over-express the USP11 in KFBs. Influence of USP11 on proliferation, invasion and migration of KFBs, and expression level of TβRII, Smad2, Smad3, α-SMA, collagen1 and collagen3 were assayed by CCK8, scratching, transwell, Western blot and real-time quantitative polymerase chain reaction. The interactions between USP11 and TβRII were examined using ubiquitination assays and co-immunoprecipitation. To further confirm the role of USP11 in keloid growth, we performed animal experiments.

RESULTS

Results show that down-regulated USP11 markedly suppressed the ability of proliferation, invasion and migration of keloid derived-fibroblasts in vitro and reduce the expression of TβRII, Smad2, Smad3, αSMA, collagen1 and collagen3. In addition, over-expression of USP11 demonstrated the contrary tendency. Ubiquitination experiments and co-immunoprecipitation demonstrated that USP11 was interacting with TβRII and deubiquitinated TβRII. Interferences with USP11 inhibited growth of keloid in vivo. Additionally, we have verified that knockdown of USP11 has no significant effect on normal skin fibroblasts.

CONCLUSION

USP11 elevates the ability of proliferation, collagen deposition, invasion and migration of keloid-derived fibroblasts by deubiquitinating TβRII.

Identification of inflammation-related biomarkers in keloids

Background

The relationship between inflammation-related genes (IRGs) and keloid disease (KD) is currently unclear. The aim of this study was to identify a new set of inflammation-related biomarkers in KD.

Methods

GSE145725 and GSE7890 datasets were used in this study. A list of 3026 IRGs was obtained from the Molecular Signatures Database. Differentially expressed inflammation-related genes (DEGs) were obtained by taking the intersection of DEGs between KD and control samples and the list of IRGs. Candidate genes were selected using least absolute shrinkage and selection operator (LASSO) regression analysis. Candidate genes with consistent expression differences between KD and control in both GSE145725 and GSE7890 datasets were screened as biomarkers. An alignment diagram was constructed and validated, and in silico immune infiltration analysis and drug prediction were performed. Finally, RT-qPCR was performed on KD samples to analyze the expression of the identified biomarkers.

Results

A total of 889 DEGs were identified from the GSE145725 dataset, 169 of which were IRGs. Three candidate genes (TRIM32, LPAR1 and FOXF1) were identified by the LASSO regression analysis, and expression validation analysis suggested that FOXF1 and LPAR1 were down-regulated in KD samples and TRIM32 was up-regulated. All three candidate genes had consistent changes in expression in both the GSE145725 and GSE7890 datasets. An alignment diagram was constructed to predict KD. Effector memory CD4 T cells, T follicular helper cell, Myeloid derived suppressor cell, activated dendritic cell, Immature dendritic cell and Monocyte were differentially expressed between the KD and control group. Sixty-seven compounds that may act on FOXF1, 108 compounds that may act on LPAR1 and 56 compounds that may act on TRIM32 were predicted. Finally, RT-qPCR showed that the expression of LPAR1 was significantly lower in KD samples compared to normal samples whereas TRIM32 was significantly higher, while there was no difference in the expression of FOXF1.

Conclusion

This study provides a new perspective to study the relationship between IRGs and KD.

Support for dermatological research in Sub-Saharan Africa: insights from African hair and skin research programs

BACKGROUND

The structure and physiology of skin and hair in people of African ancestry are different from other ethnic categories and studies from other continents cannot necessarily be extrapolated to Sub-Saharan Africa (SSA) due to the differences in genetics, lifestyle, climate, cultures, and hair and skin care practices. The aim of this report is to highlight the recent advances in local skin and hair research in SSA from a grant program.

METHODS

African Hair and Skin Research Grants from an industrial sponsor were awarded between 2013 and 2022 on five main topics: acne, hair and scalp, keloid scars, atopic dermatitis, and air pollution. A literature search in Scopus identified publications on these topics in African or black skin in SSA and worldwide to provide insight into the impact of the program.

RESULTS

The number of publications from around the world on the skin and hair of people of African ancestry has increased significantly over the past 30 years on all five topics, especially as a result studies conducted in the United States. Fewer studies have been conducted in SSA but there has been an increasing number of publications over the past 10 years, especially from South Africa.

CONCLUSIONS

Scientific and clinical partnerships between the industry, academia, and public healthcare sectors have contributed to a steady increase in hair and skin publications from SSA, which may be useful for the development of tailored products and public educational campaigns to raise awareness of the risks of using inappropriate products.

Analysis of subsets and localization of macrophages in skin lesions and peripheral blood of patients with keloids

Keloids are a type of abnormal fibrous proliferation disease of the skin, characterized by local inflammation that lacks clear pathogenesis and satisfactory treatment. The phenomenon of distinct phenotypes, including M1 and M2 macrophages, is called macrophage polarization. Recently, macrophage polarization has been suggested to play a role in keloid formation. This study aimed to evaluate the relation between macrophage polarization and keloids and identify novel effective treatments for keloids. Differentially expressed genes were identified via RNA sequencing of the skin tissue of healthy controls and patients with keloids and validated using quantitative PCR. Multiplex immunofluorescence microscopy was used to detect different phenotypes of macrophages in keloid tissues. Finally, quantitative PCR validation of differentially expressed genes and flow cytometry were used to analyze macrophages in the peripheral blood of healthy controls and patients with keloids. Total and M2 macrophages were significantly increased in the local skin tissue and peripheral blood of patients with keloids compared with healthy controls. In addition, inflammation- and macrophage polarization-related differentially expressed genes in keloid tissue showed similar expression patterns in the peripheral blood. This study highlighted an increased frequency of total macrophages and M2 polarization in the local skin tissue and peripheral blood of patients with keloids. This systematic macrophage polarization tendency also indicates a potential genetic predisposition to keloids. These findings suggest the possibility of developing new diagnostic and therapeutic indicators for keloids focusing on macrophages.

Tripterine Inhibits Proliferation and Promotes Apoptosis of Keloid Fibroblasts by Targeting ROS/JNK Signaling

Keloids are benign skin tumors characterized by excessive fibroblast proliferation and collagen deposition. The current treatment of keloids with hormone drug injection, surgical excision, radiotherapy, physical compression, laser therapy, cryotherapy often have unsatisfactory outcomes. The phytochemical compounds have shown great potential in treating keloids. Tripterine, a natural triterpene derived from the traditional Chinese medicine Thunder God Vine (Tripterygium wilfordii), was previously reported to exhibit an anti-scarring bioactivity in mouse embryonic fibroblast NIH/3T3 cells. Accordingly, our study was dedicated to explore its role in regulating the pathological phenotypes of keloid fibroblasts. Human keloid fibroblasts were treated with tripterine (0-10 μM) for 24 hours. Cell viability, proliferation, migration, apoptosis, and extracellular matrix (ECM) deposition were determined by CCK-8, EdU, wound healing, Transwell, flow cytometry, western blotting, and RT-qPCR assays. The effects of tripterine treatment on reactive oxygen species (ROS) generation and JNK activation in keloid fibroblasts were assessed by DCFH-DA staining and western blotting analysis. Tripterine at the concentrations higher than 4 μM attenuated the viability of human keloid fibroblasts in a dose-dependent manner. Treatment with tripterine (4, 6, and 8 μM) dose-dependently inhibited cell proliferation and migration, promoted cell apoptosis, reduced α-SMA, Col1, and Fn expression, induced ROS production, and enhanced JNK phosphorylation in keloid fibroblasts. Collectively, tripterine ameliorates the pathological characteristics of keloid fibroblasts that are associated with keloidformation and growth by inducing ROS generation and activating JNK signalingpathway.

Paper Tape May Improve Scar Aesthetics and Prevent Wound Closure Complications

There is uncertainty whether postoperative application of paper tape (PT) improves scar aesthetics and reduces wound closure complications. This study aimed to review and assess the quality of applicable findings from studies investigating PT's efficacy. We queried PubMed and SCOPUS using the search terms "(("paper tape") AND (wound OR closure OR heal* OR complication OR skin OR prevent* OR scar*))." We excluded articles that were duplicates, basic science, or not clinically relevant. We assessed the level of evidence for each article using the American Society of Plastic Surgeons (ASPS) Rating Levels of Evidence and Grading Recommendations for Therapeutic Studies, ranging from I (highest) to V (lowest). Of 186 publications reviewed, we included eight studies in the literature review. Five of these studies reported statistically significant positive outcomes on scar aesthetics and wound closure associated with using PT. Using the ASPS rating system, we found that two studies were Level I, three studies were Level II, two studies were Level IV, and one study was Level V. Notably, heterogeneity in the study designs limited outcome comparison. The data from the studies included in this literature review support using PT to optimize scar and wound management. The lack of higher levels of evidence, however, suggests the need for additional randomized controlled trials to rigorously evaluate patient outcomes when using PT compared with other forms of adhesive dressings.

Scars

Wound healing occurs as a response to disruption of the epidermis and dermis. It is an intricate and well-orchestrated response with the goal to restore skin integrity and function. However, in hundreds of millions of patients, skin wound healing results in abnormal scarring, including keloid lesions or hypertrophic scarring. Although the underlying mechanisms of hypertrophic scars and keloid lesions are not well defined, evidence suggests that the changes in the extracellular matrix are perpetuated by ongoing inflammation in susceptible individuals, resulting in a fibrotic phenotype. The lesions then become established, with ongoing deposition of excess disordered collagen. Not only can abnormal scarring be debilitating and painful, it can also cause functional impairment and profound changes in appearance, thereby substantially affecting patients' lives. Despite the vast demand on patient health and the medical society, very little progress has been made in the care of patients with abnormal scarring. To improve the outcome of pathological scarring, standardized and innovative approaches are required.

Application of 3D Transparent Facemasks in Long-Term Outpatient Rehabilitation of Facial Scars After Burns: A Retrospective Cohort Study of Improved Appearance of Target Scars With Different Healing Time

Severe facial burns may cause scarring problems and affect living quality of patients. With the advent of 3D facemasks, it is being used to treat facial scars; however, its efficacy must be confirmed by adequate studies. A retrospective analysis of 26 patients who visited rehabilitation outpatient clinic from 2017 to 2022. Patients were separated into two groups based on the time to healing (TTH) following burn injury: early healing group (TTH ≤ 21 days) and late healing group (TTH > 21 days). To compare treatment outcomes and differences between the two groups, 3D facemask application was assessed using the Vancouver Scar Scale (VSS), patient satisfaction, and complications. In both groups, there were significant improvements in the total VSS scores (P < .01) and each VSS subscore (P < .01). These scar characteristics improved over time as the treatment progressed. Compared with the late healing group, the early healing group had more obvious effects on improving scar pigmentation (P < .05) and vascularity (P < .05) at similar assessment time points after burns. At the last assessment, there was a significant difference in total VSS scores between groups (P = .009). For the early and late healing groups, respectively, the mean gradient value (SE) of the total VSS scores was 1.550 (0.373) and 1.283 (0.224) over the course of the treatment periods. 3D facemasks are effective in the rehabilitation of facial scars caused by burns, which should be used for prevention and treatment in the initial stages of scar development.

Identification of a potential bioinformatics-based biomarker in keloids and its correlation with immune infiltration

Keloid formation is a pathological consequence resulting from cutaneous irritation and injury, primarily attributed to excessive collagen matrix deposition and fibrous tissue proliferation. Chronic inflammation, left uncontrolled over an extended period, also stands as a substantial contributing factor. The precise mechanisms underlying keloid formation remain unclear. Therefore, this study aimed to identify key genes for diagnostic purposes. To achieve this, we used two Gene Expression Omnibus (GEO) data sets to identify differentially expressed genes. We identified one particular gene, homeobox C9 (HOXC9), using a thorough strategy involving two algorithms (least absolute shrinkage and selection operator and support vector machine-recursive feature elimination) and weighted gene co-expression network analysis. We then assessed its expression in normal and keloid tissues. In addition, we explored its temporal expression patterns via Mfuzz time clustering analysis. In our comprehensive analysis, we observed that immune infiltration, as well as cell proliferation, are crucial to keloid formation. Thus, we investigated immune cell infiltration in the keloid and normal groups, as well as the correlation between HOXC9 and these immune cells. It was found that HOXC9 was closely associated with the immune microenvironment of keloids. This shows that HOXC9 can serve as a potential biomarker and therapeutic target for keloids.

Exploring the Potential of Hesperidin in Preventing Hypertrophic Scars: Insights from a Rabbit Ear Model

Background

Hypertrophic scars, commonly occurring after trauma or surgery in critical areas like the head and joints, pose significant challenges to both physical and mental health due to their impact on skin function and aesthetics. While the complex pathogenesis involves fibroblast activation and collagen deposition, effective treatments are lacking, underscoring the importance of exploring pathogenesis and targeted therapies. Hesperidin, a bioactive compound in citrus fruits with diverse health benefits, including anti-fibrotic and anti-angiogenic effects, is the focus of this study with the aim of investigating its impact on hypertrophic scar formation, given its potential to promote blood flow and improve skin microcirculation.

Objective

This study aimed to observe the inhibitory effect of topical hesperidin on hypertrophic scars in rabbits.

Methods

A total of 8 healthy adult New Zealand white rabbits were used to establish a rabbit hypertrophic scarring animal model. Five wounds were created on each rabbit's two ears, with three wounds on the left ear (groups A, B, and C) and two wounds on the right ear (groups D and E). After six days of wound drying postoperatively, the wounds were locally treated with medication as followed: group A, 0.1% hesperidin; group B, 1% hesperidin; group C, 1% triamcinolone acetonide; group D, Vaseline; and group E, blank control without any medication. After 28 days, the scar tissue samples were collected for histological examination.

Results

The results showed that the scar texture of groups B and C was softer and lighter in color, and the number of fibroblasts, capillaries, and inflammatory cells in the tissue was significantly less than those in the other three groups. The hypertrophic scar indices of groups B and C were significantly smaller than those of groups A, D, and E, and the difference was statistically significant (P < 0.05). There were no significant difference between groups B and C.

Conclusion

Topical application of hesperidin demonstrated promising potential for reducing hypertrophic scar formation in rabbits.

Treatment of traumatic hypertrophic scars and keloids: a systematic review of randomized control trials

Exaggerated healing and remodeling after skin injury may cause hypertrophic and keloidal scars, which are associated with functional and quality of life impairment. There is limited guidance available regarding the relative effectiveness of therapies for hypertrophic scars and keloids. In this review, we aim to compare the effectiveness of treatments for hypertrophic scars and keloids. MEDLINE, Embase, Scopus, and the Cochrane Collaboration database were searched from inception to March 2019 for randomized control trials of treatments for hypertrophic and keloid scars that included 20 or more patients. Outcomes evaluated included the standardized mean reduction in scarring and adverse events. The type of scar and the demographic features were analyzed for their effect on clinical outcome. Based on 25 included clinical trials, intralesional injection (64.1% [95% CI 60.8-67.5%]) may be more effective than physical (29.9% [95% CI 28.9-30.9%]) or topical treatments (34% [95% CI 31.8-36.8%]). Combination of 5-fluorouracil and triamcinolone (9:1 dilution) appeared superior among intralesional treatments for keloids. Ablative laser and pulsed-dye laser were the most useful laser treatments. Regression modeling showed laser treatment response was linked to Fitzpatrick skin type (p = 0.002). Adverse events were uncommon for all treatments and mostly transient. Intralesional treatments for keloid and hypertrophic scars may be the most reliable treatment option to improve pathologic scars, while laser treatment may have specific benefits for Fitzpatrick skin types I-III over types IV-VI. Management of pathological scars is an area of critical need, where appropriate treatment can have a significant impact on quality of life.

Establishment of a humanized mouse model of keloid diseases following the migration of patient immune cells to the lesion: Patient-derived keloid xenograft (PDKX) model

Keloid disorder is an abnormal fibroproliferative reaction that can occur on any area of skin, and it can impair the quality of life of affected individuals. To investigate the pathogenesis and develop a treatment strategy, a preclinical animal model of keloid disorder is needed. However, keloid disorder is unique to humans, and the development of an animal model of keloid disorder is highly problematic. We developed the patient-derived keloid xenograft (PDKX), which is a humanized mouse model, and compared it to the traditional mouse xenograft model (transplantation of only keloid lesions). To establish the PDKX model, peripheral mononuclear cells (PBMCs) from ten keloid patients or five healthy control subjects were injected into NOD/SCID/IL-2Rγnull mice, and their keloid lesions were grafted onto the back after the engraftment of immune cells (transplantation of keloid lesions and KP PBMCs or HC PBMCs). Four weeks after surgery, the grafted keloid lesion was subjected to histologic evaluation. Compared to the traditional model, neotissue formed along the margin of the grafted skin, and lymphocyte infiltration and collagen synthesis were significantly elevated in the PDKX model. The neotissue sites resembled the margin areas of keloids in several respects. In detail, the levels of human Th17 cells, IL-17, HIF-1a, and chemokines were significantly elevated in the neotissue of the PDKX model. Furthermore, the weight of the keloid lesion was increased significantly in the PDKX model, which was due to the proinflammatory microenvironment of the keloid lesion. We confirmed that our patient-derived keloid xenograft (PDKX) model mimicked keloid disorder by recapitulating the in vivo microenvironment. This model will contribute to the investigation of cellular mechanisms and therapeutic treatments for keloid disorders.

Topical gel containing Polysiloxanes and hyaluronic acid for skin scar: Formulation design, characterization, and In vivo activity

BACKGROUND

Scar formation is undesirable both cosmetically and functionally. It shows that silicone gel is effective in preventing and improving scars formed due to a wound formation after injury.

OBJECTIVES

This study investigates whether a silicone gel composition based on a novel concept of infusing a biologically active material such as hyaluronic acid and/or salts with various polysiloxane derivatives in a specific proportion to achieve desired viscosity range and their action has a synergistic beneficial effect on skin scar after injury.

METHODS

We have developed a topical gel utilizing a combination of emulsifiers, sodium hyaluronate, polysiloxane, and its derivatives. The method of preparation comprises mixing of aqueous phase dispersion and polysiloxanes blend under stirring at room temperature.

RESULTS

It results in the formation of a homogenous smooth gel formulation. The developed topical gel formulation was characterized for physicochemical properties, rheology, stability, and anti-scar activity in Wistar rats. It was found that the developed formulation system consists of desirable attributes for skin applications. In vivo investigation of developed polysiloxane gel formulation for anti-scar activity shown promising outcomes compared to marketed product (Kelo-cote scar gel). Furthermore, a histopathology study of healed skin tissues observed the formation of microscopic skin structures compared to the Kelo-cote scar gel.

CONCLUSIONS

It indicates that the combination of polysiloxanes and sodium hyaluronate resulting an improvement in anti-scar activity compared to the marketed product containing polysiloxanes alone.

Platycodin D inhibits the proliferation and migration of hypertrophic scar-derived fibroblasts and promotes apoptosis through a caspase-dependent pathway

Abnormal fibroblast proliferation and excessive extracellular matrix (ECM) deposition lead to the formation of hypertrophic scars (HSs). However, there is no satisfactory method to inhibit the occurrence and development of HSs. In our study, platycodin D (PD), a natural compound extracted from Platycodon grandiflorus, inhibited HSs formation both in vitro and in vivo. First, qRT-PCR and Western blot were used to confirm PD dose-dependently downregulated the expression of Col I, Col III and α-SMA in human hypertrophic scar-derived fibroblasts (HSFs) (p < 0.05). Second, cck-8, transwell and wound healing assays verified PD suppressed the proliferation (p < 0.05) and migration of HSFs (p < 0.05), and inhibited the differentiation of HSFs into myofibroblasts. Moreover, PD-induced HSFs apoptosis were analyzed by flow cytometry and the apoptosis was activated through a caspase-dependent pathway. The rabbit ear scar model was used to further confirm the inhibitory effect of PD on collagen and α-SMA deposition. Finally, Western blot analysis showed that PD reduced TGF-β RI expression (p < 0.05) and affected matrix metalloproteinase 2 (MMP2) protein levels (p < 0.05). In conclusion, our study showed that PD inhibited the proliferation and migration of HSFs by inhibiting fibrosis-related molecules and promoting apoptosis via a caspase-dependent pathway. The TGF-β/Smad pathway also mediated the inhibition of HSFs proliferation and HSFs differentiation into myofibroblasts. Therefore, PD is a potential therapeutic agent for HSs and other fibrotic diseases.

The transcriptional profile of keloidal Schwann cells

Recently, a specific Schwann cell type with profibrotic and tissue regenerative properties that contributes to keloid formation has been identified. In the present study, we reanalyzed published single-cell RNA sequencing (scRNA-seq) studies of keloids, healthy skin, and normal scars to reliably determine the specific gene expression profile of keloid-specific Schwann cell types in more detail. We were able to confirm the presence of the repair-like, profibrotic Schwann cell type in the datasets of all three studies and identified a specific gene-set for these Schwann cells. In contrast to keloids, in normal scars, the number of Schwann cells was not increased, nor was their gene expression profile distinctly different from that of Schwann cells of normal skin. In addition, our bioinformatics analysis provided evidence for a role of transcription factors of the AP1, STAT, and KLF families, and members of the IER genes in the dedifferentiation process of keloidal Schwann cells. Together, our analysis strengthens the role of the profibrotic Schwann cell type in the formation of keloids. Knowledge of the exact gene expression profile of these Schwann cells will facilitate their identification in other organs and diseases.

Exosomes from human adipose-derived mesenchymal stem cells inhibit production of extracellular matrix in keloid fibroblasts via downregulating transforming growth factor-β2 and Notch-1 expression

Keloids are an excessive tissue response to dermal damage, characterized by uncontrolled growth and a high recurrence rate after various treatments. Abnormalities with the extracellular matrix (ECM) are one of the most important contributing factors to the formation of keloids. Although exosomes from human adipose-derived mesenchymal stem cells (adMSC-Exos) have been shown to promote repair and regeneration in wounds, they have seldom been studied for the treatment of keloids. In this study, we aimed to investigate the effects of adMSC-Exos on ECM remodeling in keloids using both in vitro and ex vivo models. The results showed that adMSC-Exos inhibited gene and protein expression of collagen I (COL-1), collagen III (COL-3), fibronectin (FN), and α-smooth muscle actin (α-SMA) in keloid fibroblasts (KFs). Furthermore, using an ex vivo tissue explant model, we found that adMSC-Exos significantly suppressed COL production and disrupted the microvessel stucture. We also demonstrated that adMSC-Exos inhibited the protein expression of Smad3 and Notch-1, and the expression of transforming growth factor β2 (TGF-β2) in KFs, and promoted the expression of TGF-β3. These findings largely explain the mechanisms underlying the inhibition of ECM production in keloids by adMSC-Exos. In conclusion, our results revealed that adMSC-Exos effectively inhibited the production of ECM in keloids, which provides a new potential alternative for the systemic treatment of keloids.

Dermal Fibroblast Heterogeneity and Its Contribution to the Skin Repair and Regeneration

Significance: Dermal fibroblasts are the major cell type in the skin's dermal layer. These cells originate from distinct locations of the embryo and reside in unique niches in the dermis. Different dermal fibroblasts exhibit distinct roles in skin development, homeostasis, and wound healing. Therefore, these cells are becoming attractive candidates for cell-based therapies in wound healing. Recent Advances: Human skin dermis comprises multiple fibroblast subtypes, including papillary, reticular, and hair follicle-associated fibroblasts, and myofibroblasts after wounding. Recent studies reveal that these cells play distinct roles in wound healing and contribute to diverse healing outcomes, including nonhealing chronic wound or excessive scar formation, such as hypertrophic scars (HTS) and keloids, with papillary fibroblasts having antiscarring and reticular fibroblast scar-forming properties. Critical Issues: The identities and functions of dermal fibroblast subpopulations in many respects remain unknown. In this review, we summarize the current understanding of dermal fibroblast heterogeneity, including their defined cell markers and dermal niches, dynamic changes, and contributions to skin wound healing, with the emphasis on scarless healing, healing with excessive scars (HTS and keloids), chronic wounds, and the potential application of this heterogeneity for developing cell-based therapies that allow wounds to heal faster with less scarring. Future Directions: Heterogeneous dermal fibroblast populations and their functions are poorly characterized. Refining and advancing our understanding of dermal fibroblast heterogeneity and their participation in skin homeostasis and wound healing may create potential therapeutic applications for nonhealing chronic wounds or wounds that heal with excessive scarring.

OMICS Approaches Evaluating Keloid and Hypertrophic Scars

Abnormal scar formation during wound healing can result in keloid and hypertrophic scars, which is a major global health challenge. Such abnormal scars can cause significant physiological pain and psychological distress and become a financial burden. Due to the biological complexity of scar formation, the pathogenesis of such scars and how to prevent them from forming remains elusive. In this review paper, we delve into the world of "omics" approaches to study abnormal scars and provide examples of genomics, transcriptomics, proteomics, epigenomics, and metabolomics. The benefits of "omics" approaches are that they allow for high-throughput studies and the analysis of 100s to 1000s of genes and proteins with the accumulation of large quantities of data. Currently in the field, there is a lack of "omics" review articles describing pathological scars. In this review, we summarize genome-wide linkage analysis, genome-wide association studies, and microarray data to name a few omics technologies. Such data can provide novel insights into different molecular pathways and identify novel factors which may not be captured through small-scale laboratory techniques.

Evaluation of the Effects of Human Dental Pulp Stem Cells on the Biological Phenotype of Hypertrophic Keloid Fibroblasts

OBJECTIVE

Despite numerous existing treatments for keloids, the responses in the clinic have been disappointing, due to either low efficacy or side effects. Numerous studies dealing with preclinical and clinical trials have been published about effective therapies for fibrotic diseases using mesenchymal stem cells; however, no research has yet been reported to scientifically investigate the effect of human dental pulp stem cells (HDPSCs) on the treatment of keloids. The objective is to provide an experimental basis for the application of stem cells in the treatment of keloids.

METHODS

Human normal fibroblasts (HNFs) and human keloid fibroblasts (HKFs) were cultured alone and in combination with HDPSCs using a transwell cell-contact-independent cell culture system. The effects of HDPSCs on HKFs were tested using a CCK-8 assay, live/dead staining assay, quantitative polymerase chain reaction, Western blot and immunofluorescence microscopy.

RESULTS

HDPSCs did not inhibit the proliferation nor the apoptosis of HKFs and HNFs. HDPSCs did, however, inhibit their migration. Furthermore, HDPSCs significantly decreased the expression of profibrotic genes (CTGF, TGF-β1 and TGF-β2) in HKFs and KNFs (p < 0.05), except for CTGF in HNFs. Moreover, HDPSCs suppressed the extracellular matrix (ECM) synthesis in HKFs, as indicated by the decreased expression of collagen I as well as the low levels of hydroxyproline in the cell culture supernatant (p < 0.05).

CONCLUSIONS

The co-culture of HDPSCs inhibits the migration of HKFs and the expression of pro-fibrotic genes, while promoting the expression of anti-fibrotic genes. HDPSCs' co-culture also inhibits the synthesis of the extracellular matrix by HKFs, whereas it does not affect the proliferation and apoptosis of HKFs. Therefore, it can be concluded that HDPSCs can themselves be used as a tool for restraining/hindering the initiation or progression of fibrotic tissue.

Validation strategies for identifying drug targets in dermal fibrotic disorders

Fibrotic skin disorders, such as keloid disease (KD), are common clinically challenging disorders with unknown etiopathogenesis and ill-defined treatment strategies that affect millions of people worldwide. Thus, there is an urgent need to discover novel therapeutics. The validation of potential drug targets is an obligatory step in discovering and developing new therapeutic agents for the successful treatment of dermal fibrotic conditions, such as KD. The integration of multi-omics data with traditional and modern technological approaches, such as RNA interference (RNAi) and genome-editing tools, would provide unique opportunities to identify and validate novel targets in KD during early drug development. Thus, in this review, we summarize the current and emerging drug discovery process with a focus on validation strategies of potential drug targets identified in dermal fibrosis.

GLUT-1 Enhances Glycolysis, Oxidative Stress, and Fibroblast Proliferation in Keloid

A keloid is a fibroproliferative skin tumor. Proliferating keloid fibroblasts (KFs) demand active metabolic utilization. The contributing roles of glycolysis and glucose metabolism in keloid fibroproliferation remain unclear. This study aims to determine the regulation of glycolysis and glucose metabolism by glucose transporter-1 (GLUT-1), an essential protein to initiate cellular glucose uptake, in keloids and in KFs. Tissues of keloids and healthy skin were explanted for KFs and normal fibroblasts (NFs), respectively. GLUT-1 expression was measured by immunofluorescence, RT-PCR, and immunoblotting. The oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were measured with or without WZB117, a GLUT-1 inhibitor. Reactive oxygen species (ROS) were assayed by MitoSOX immunostaining. The result showed that glycolysis (ECAR) was enhanced in KFs, whereas OCR was not. GLUT-1 expression was selectively increased in KFs. Consistently, GLUT-1 expression was increased in keloid tissue. Treatment with WZB117 abolished the enhanced ECAR, including glycolysis and glycolytic capacity, in KFs. ROS levels were increased in KFs compared to those in NFs. GLUT-1 inhibition suppressed not only the ROS levels but also the cell proliferation in KFs. In summary, the GLUT-1-dependent glycolysis and ROS production mediated fibroblast proliferation in keloids. GLUT1 might be a potential target for metabolic reprogramming to treat keloids.

A comparison study of the 0.1% tretinoin cream versus fractional microneedle radiofrequency combination with fractional CO2 laser for the treatment of striae alba in Indonesian patients

Striae distensae (SD) are linear scar tissue in the dermis that arises from stretching the skin. There are two types of SD, striae rubrae and striae albae (SA) which is marked with a line hypopigmentation that cause a psychological problem, especially in the high skin type. The standard therapy is a 0.1% tretinoin cream, but it takes a long time to reach the collagen so it needs invasive measures to reach these targets. This study was comparing 0.1% tretinoin cream with combination therapy of fractional microneedle radiofrequency (FMR) and fractional CO₂ laser for SA. The number of subjects in this study was 11 patients each group with Fitzpatrick skin types IV or V. Biopsy was taken before and after therapy. The clinical changes in SA lesions in this study were represented by measurements of the length and width. The percentage of collagen area is the amount of collagen fibers with Masson's trichrome staining. The clinical changes of lesion in the combination therapy decreased. The percentage change in collagen area in the combination therapy group had a higher increase. The side effect experienced by all combination group subjects was postinflammatory hyperpigmentation, two subjects in 0.1% tretinoin cream group experienced irritation.

Assessment of various intralesional injections in keloid: Comparative analysis

AIM

Intralesional triamcinolone is a gold standard in treating the keloids to comparation its effectiveness versus intralesional 5-fluorouracil intralesional verapamil and intralesional platelet-rich plasma.

PATIENTS AND METHODS

Several 160-cases were categorized into four groups of each Group-Containing 40 cases. Group-A (control) treated with intralesional triamcinolone and Group-B intralesional verapamil, Group-C intralesional 5-fluorouracil, and Group-D intralesional platelet-rich plasma. Patients were assessed for clinical response based on a decrease in the patient and observer scar assessment scale (POSAS) at baseline and the end of treatment.

RESULTS

The mean base-line POSAS score was 91 ± 10.98 SD check-in Group-A, 90 ± 10.85 in Group-B, 89 ± 10.06 in Group-C, and 92 ± 10.84 in Group-D.POSAS score after 24 weeks 36 ± 12.74 in Group-A, 29 ± 10.91 in Group-B, 39 ± 13.74 in Group-C, 36 ± 12.74 in Group-D. Statistically, a significant difference was observed between groups.

CONCLUSION

Intralesional verapamil reported to be the most effective therapy and platelet-rich plasma was effective as intralesional triamcinolone acetonide with no serious side effects and 5-fluorouracil was less effective in treating the keloids.

Pre-Emptive Priming of Human Skin Improves Cutaneous Scarring and Is Superior to Immediate and Delayed Topical Anti-Scarring Treatment Post-Wounding: A Double-Blind Randomised Placebo-Controlled Clinical Trial

The concept of pre-emptive priming of skin pre-surgery offers a novel approach in optimizing cutaneous scarring outcome. We previously showed an anti-scarring topical (epigallocatechin-3-gallate (EGCG)) is effective in improving skin scarring when applied post-surgery. The objective was to deliver an active compound at the optimal time in order to maximize its impact and improve cutaneous scarring. Therefore, pre-emptive application of anti-scarring topical pre-surgery compared with post-surgery can potentially be superior on scarring outcome. This double-blinded randomized placebo-controlled trial compares the effects of pre-emptive priming of skin with an anti-scarring topical pre-surgery versus post-surgery. Healthy volunteers (n = 40) were split into 4-groups; each undergoing different modes of application versus placebo: Group-1 = priming (7Days) pre-injury, Group-2 = priming (3D) pre-injury, Group-3 = immediate (0D) day-of-injury, Group-4 = delayed application (14D) post-injury. Excisional skin-biopsies in upper-arms were evaluated weekly with multiple quantitative devices over 8-weeks. Histological, immunohistochemical, mRNA sequencing and QRT-PCR studies were performed on tissue-biopsies. EGCG reduced mast cells at weeks-4 and 8 by gene and protein analyses (p < 0.01). Group 1 was superior to other groups (p < 0.01) in both clinical (blood flow) and laboratory parameters (elastin and immune marker expression). Additionally, there was down-regulation of angiogenic-markers by mRNA-sequencing and of CD31 and VEGF-A at weeks-4 and 8 (p < 0.01) by immunohistochemistry and at week-4 (p < 0.05) by QRT-PCR. EGCG increased antioxidant levels (HO-1) at week-4 (p < 0.01) plus elastin at week-8 (p < 0.01). In conclusion, pre-emptive priming of skin pre-injury has significant beneficial effects on surgically induced skin scarring shown by reducing mast cells, blood flow and angiogenesis plus increasing elastin content. This clinical trial was registered with ISRCTN (ISRCTN70155584).

Pre-Emptive Priming of Human Skin Improves Cutaneous Scarring and Is Superior to Immediate and Delayed Topical Anti-Scarring Treatment Post-Wounding: A Double-Blind Randomised Placebo-Controlled Clinical Trial

The concept of pre-emptive priming of skin pre-surgery offers a novel approach in optimizing cutaneous scarring outcome. We previously showed an anti-scarring topical (epigallocatechin-3-gallate (EGCG)) is effective in improving skin scarring when applied post-surgery. The objective was to deliver an active compound at the optimal time in order to maximize its impact and improve cutaneous scarring. Therefore, pre-emptive application of anti-scarring topical pre-surgery compared with post-surgery can potentially be superior on scarring outcome. This double-blinded randomized placebo-controlled trial compares the effects of pre-emptive priming of skin with an anti-scarring topical pre-surgery versus post-surgery. Healthy volunteers (n = 40) were split into 4-groups; each undergoing different modes of application versus placebo: Group-1 = priming (7Days) pre-injury, Group-2 = priming (3D) pre-injury, Group-3 = immediate (0D) day-of-injury, Group-4 = delayed application (14D) post-injury. Excisional skin-biopsies in upper-arms were evaluated weekly with multiple quantitative devices over 8-weeks. Histological, immunohistochemical, mRNA sequencing and QRT-PCR studies were performed on tissue-biopsies. EGCG reduced mast cells at weeks-4 and 8 by gene and protein analyses (p < 0.01). Group 1 was superior to other groups (p < 0.01) in both clinical (blood flow) and laboratory parameters (elastin and immune marker expression). Additionally, there was down-regulation of angiogenic-markers by mRNA-sequencing and of CD31 and VEGF-A at weeks-4 and 8 (p < 0.01) by immunohistochemistry and at week-4 (p < 0.05) by QRT-PCR. EGCG increased antioxidant levels (HO-1) at week-4 (p < 0.01) plus elastin at week-8 (p < 0.01). In conclusion, pre-emptive priming of skin pre-injury has significant beneficial effects on surgically induced skin scarring shown by reducing mast cells, blood flow and angiogenesis plus increasing elastin content. This clinical trial was registered with ISRCTN (ISRCTN70155584).

Migraines and keloids: a 15-year Taiwan claim database analysis

Background

Fibroproliferative lesions with intractable pruritus, pain and hyperesthesia that cause uncontrolled scar growth are known as keloids. Migraines are common upsetting headache disorders characterised by frequent recurrence and attacks aggravated by physical activity. Both keloids and migraines can cause physical exhaustion and discomfort in patients; they have similar pathophysiological pathways, that is, the transforming growth factor-β1 gene and neurogenic inflammation.

Objective

To investigate subsequent development of migraines in patients with keloids.

Methods

Data were retrieved from the Taiwan National Health Insurance Research Database. The keloids group included patients aged 20 years and older with a recent diagnosis of keloids(n=9864). The non-keloids group included patients without keloids matched for gender and age at 1–4 ratio (n=39 456). Migraine risk between groups was measured by Cox proportional hazards regression models. Incidence rates and hazard ratios were calculated.

Results

During the study period, 103 keloids patients and 323 non-keloids patients developed migraines. The keloids patients had a 2.29-fold greater risk of developing migraines compared with the non-keloids group after adjustment for covariates (1.81 vs 0.55 per 1000 person-years, respectively). In the keloids group, female or patients younger than 50 years were prone to developing migraines.

Conclusion

The higher tendency to develop migraines in the keloids group in comparison with the non-keloids group suggests that keloids could be a predisposing risk factor for migraine development in adults. Keloids patients who complain of headaches should be examined for migraines.

Identification of differentially expressed circular RNAs in keloid and normal skin tissue by high-throughput sequencing

Keloid is a kind of pathological skin scar with unclear molecular pathology. Circular RNAs (circRNAs) are involved in the occurrence and development of many diseases; however, their relationship with keloid is not well understood. To investigate the involvement of dysregulated circRNAs in keloid. Thirty-seven keloids and 37 normal skin tissues were collected, and the changes of circRNAs, microRNAs (miRNAs) and mRNAs in 3 keloids and 3 normal samples by high-throughput sequencing were detected first. Based on the circRNA-miRNA-mRNA interaction network construction, gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis combining several signaling pathways associated with keloid formation and progression, the circRNAs required further verification were screened out. The expression levels of the selected circRNAs were verified in 37 keloids and 37 normal skin tissues using quantitative real-time polymerase chain reaction (QPCR). The interaction of candidate circRNA and its predicted binding miRNA was tested by dual-luciferase reporter gene experiment. Compared with normal controls, there was an average of 120 and 12 circRNAs, 44 and 63 miRNAs, 656 and 156 mRNAs were upregulated and downregulated, respectively, in keloids. According to the analysis of bioinformation, six circRNAs were picked out. The QPCR validation results of two upregulated circRNAs (hsa_circ_0001320 and circCOL5A1) were consistent with previous sequencing results. The interaction between hsa_circ_0001320 and miR-574-5p was confirmed. This study makes it clear that the abnormal expression of circRNAs may be related to the pathological process of keloid.

Treatment of keloids through Runx2 siRNA‑induced inhibition of the PI3K/AKT signaling pathway

Keloids are a skin fibroproliferative condition characterized by the hyperproliferation of fibroblasts and the excessive deposition of extracellular matrix (ECM) components. Previous studies have determined that Caveolin-1 controlled hyperresponsiveness to mechanical stimuli through Runt-related transcription factor 2 (Runx2) activation in keloids. However, the molecular mechanism of Runx2 regulating the pathological progression of keloids has not been elucidated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that most of the differentially expressed genes (DEGs), including Runx2, were significantly enriched in the biological processes ‘Positive regulation of cell proliferation’, in the cellular components ‘Extracellular matrix’, in the molecular functions ‘Extracellular matrix structural constituents’ and in the KEGG ‘PI3K-Akt signaling pathway’. The aim of the present study was to investigate the expression levels of the Runx2 in human keloid tissues and primary human keloid fibroblasts (HKFs), and to determine the underlying molecular mechanisms involved in the fibrotic roles of Runx2 in keloid formation. Runx2 expression levels were analyzed in patient keloid tissues and HKFs using western blotting, reverse transcription-quantitative PCR (RT-qPCR) and immunofluorescence microscopy. Primary HKFs were transfected with a small interfering RNA (si) specifically targeting Runx2 (si-Runx2). Subsequently, Cell Counting Kit-8, wound healing and Transwell assays, flow cytometry, RT-qPCR and western blotting were applied to evaluate the proliferation, migration, apoptosis, ECM deposition and PI3K/AKT signaling pathway of HKFs, respectively. In addition, western blotting was also used to determine the expression levels of phosphorylated AKT and PI3K in HKFs. The results revealed that Runx2 expression levels were upregulated in keloid tissues and primary HKFs compared with the normal skin tissues and human normal fibroblasts. Following the transfection with si-Runx2, the proliferative and migratory abilities of HKFs were significantly reduced and the apoptotic rate was increased. The expression levels of type I, type III collagen, fibronectin, and α-smooth muscle actin were downregulated in si-Runx2-transfected cells, which was hypothesized to occur through following the downregulation of the phosphorylation levels of PI3K and AKT. In conclusion, the findings of the present study indicated that Runx2 silencing in HKFs might significantly inhibit the cell proliferation, migration and the expression levels of ECM-related proteins, and promote apoptosis via suppressing the PI3K/AKT signaling pathway. Thus, Runx2 siRNA treatment may reverse the pathological phenotype of keloids through the inhibition of PI3K/AKT signaling in patients.

Mast Cells in Skin Scarring: A Review of Animal and Human Research

Mast cells (MCs) are an important immune cell type in the skin and play an active role during wound healing. MCs produce mediators that can enhance acute inflammation, stimulate re-epithelialisation as well as angiogenesis, and promote skin scarring. There is also a link between MCs and abnormal pathological cutaneous scarring, with increased numbers of MCs found in hypertrophic scars and keloid disease. However, there has been conflicting data regarding the specific role of MCs in scar formation in both animal and human studies. Whilst animal studies have proved to be valuable in studying the MC phenomenon in wound healing, the appropriate translation of these findings to cutaneous wound healing and scar formation in human subjects remains crucial to elucidate the role of these cells and target treatment effectively. Therefore, this perspective paper will focus on evaluation of the current evidence for the role of MCs in skin scarring in both animals and humans in order to identify common themes and future areas for translational research.

CO2 Fractional Laser Combined with 5-Fluorouracil Ethosomal Gel Treatment of Hypertrophic Scar Macro-, Microscopic, and Molecular Mechanism of Action in a Rabbit Animal Model

The treatment of hypertrophic scar (HS) has thus far been a clinical challenge. We evaluated the therapeutic effect of CO₂ fractional laser combined with 5-fluorouracil ethosomal gel (5-FU EG) in rabbit HS model. HS model was established as standardized scars on the ventral surface of rabbit ears, divided into four groups: control (no intervention), EG treatment, laser treatment, and combined treatment group (laser plus 5-FU EG). Clinical macroscopic and H&E-stained microscopic observations were conducted to assess HS improvement. The mRNA levels of types I and III collagen, transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) were detected by real-time PCR. After 14 days, H&E staining shows that the thickness of HS in treatment groups was significantly lower compared with the control group, and the thickness in laser treatment group and combined treatment group was significantly lower compared with the EG treatment group. The mRNA levels of types I and III collagen, TGF-β1 were significantly low in all treatment groups, whereas IL-6 was highest in the laser treatment group at day 14. The macro- and microscopic effects of the combined and CO₂ fractional laser treatment were better compared with 5-FU EG only. Inhibition of types I and III collagen, TGF-β1 are the possible underlying mechanism of action, whereas the function of IL-6 remains to be further studied. Our study suggests that the effect of combined 5-FU EG and laser, as well as laser-only treatment are superior to 5-FU EG monotreatment. The mechanism of HS improvement is related to reduction of collagen I/III and the inhibition of TGF-β1 expression.

Location Propensity for Keloids in the Head and Neck

Importance: The difficulty associated with concealing keloids located in the face and neck regions often results in disfigurement and psychological stress for patients. Objective: The purpose of this review is to determine if specific regions on the head and neck have a greater propensity to develop keloids to alert the facial plastic surgeon of regional keloid risk. Evidence Review: PubMed, Ovid, Cochrane, and Embase computerized searches were performed through January 2020. Two independent reviewers conducted data extraction following a predetermined protocol identifying 1445 keloid studies. Findings: The prevalence of keloids in different regions of the head and neck was evaluated among 1598 head and neck keloids in the final analysis. Three of nine studies evaluated keloids specific to the ear and described a combined 1194 ear keloids locations (53.0% lobule, 22.9% cartilaginous region, 0.3% both, and 23.7% unspecified). One study reported exclusively on 82 neck keloids 72% of which were located in the submental or submandibular region. The remaining five studies evaluated 322 head and neck keloids more generally and showed 70.2% ear, 9.6% unspecified, 6.5% peri-/postauricular, 5.6% beard area, 2.2% scalp/forehead, 2.2% chin, 1.6% lateral face, 1.6% neck, and 0.3% central face keloids. Conclusions and Relevance: The ear, periauricular regions, bearded facial regions, and submandibular and submental sites show the highest propensity for keloid development in the head and neck region. The lowest keloid risk occurred in the central face region. Risk factors in relation to facial and neck regions associated with the formation of keloids should be taken into consideration before performing elective procedures in keloid susceptible individuals.

Are Prophylactic Measures Necessary to Prevent Recurrence of Penile Keloids?

Keloid scars result from excess collagen deposition in the dermis or subcutaneous tissue in response to surgery or tissue trauma. The penis is a rare site for keloid formation, even in predisposed individuals. Only few cases of penile keloids have been reported so far. In this report, we present penile keloids complicating neonatal circumcision in twin brothers. Risk of recurrence in previous reports and measures to guard against its occurrence are also discussed.

Sustained Release of Decoy Wnt Receptor (sLRP6E1E2)-Expressing Adenovirus Using Gel-Encapsulation for Scar Remodeling in Pig Model

An adenoviral vector (Ad) expressing a Wnt decoy receptor (sLRP6E1E2) is known to induce an anti-fibrotic effect by inhibiting Wnt signaling. We evaluated its effects in vivo using pig models and attempted to introduce an alginate gel-matrix system to prolong the effect of the Ad. Transduction efficiency as to the biological activity of Ad in different forms was evaluated. Then, 50 days after the formation of full-thickness skin defects on the backs of Yorkshire pigs, scars were treated with each form of Ad. Therapeutic efficacy and various factors influencing scar formation and collagen rearrangement were analyzed. Inflammatory cell infiltration within the scar tissues was also evaluated. Decoy Wnt receptor (sLRP6E1E2)-expressing adenovirus treatment improved scar quality in a pig model. Loading this construct in alginate gel allows sustained virus release into local tissues and prolongs Ad activity, thus maintaining its therapeutic effect longer in vivo.

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

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

Efficacy and Safety of a Sublative Bipolar Fractional Radiofrequency System Combined With Topical Tretinoin in Treating Striae Gravidarum: A Randomized Pilot Study

BACKGROUND

Striae gravidarum is a common skin condition resulting after pregnancy, caused by fibroblast dysfunction. Although not considered a disease, it may be considered cosmetically unpleasant to sufferers and remains as a therapeutic challenge to date.

OBJECTIVE

To evaluate the efficacy and safety of a sublative bipolar fractional radiofrequency (FRF) system, associated with 0.1% topical tretinoin, in treating striae gravidarum.

MATERIALS AND METHODS

Eighteen Chinese women with striae gravidarum on the abdomen were enrolled in the study. The target area of each patient was divided into 4 sites randomly: control, tretinoin, FRF, and tretinoin and FRF. Fractional RF was used 3 times, with 3-month intervals. Changes to striae gravidarum were evaluated through subjective scaling and objective measures, using both high-frequency ultrasound and histological study.

RESULTS

Both subjective assessment and skin thickness differences demonstrated significant improvement in the combination site (p < .001). Average optical density and density percentage of neocollagen and elastic fibers were also markedly increased in the combination site (p < .05). The adverse effects of FRF were limited to mild pain and transient erythema, edema, and microcrusts.

CONCLUSION

The combined therapy of FRF and topical tretinoin may be a potential method in treating striae gravidarum, with satisfactory efficacy and limited side effects.

Keloids: Current and emerging therapies

Keloids are pathological scars that grow over time and extend beyond the initial site of injury after impaired wound healing. These scars frequently recur and rarely regress. They are aesthetically disfiguring, can cause pain, itching, discomfort as well as psychological stress, often affecting quality of life. Many treatment modalities, including surgical and non-surgical, have been explored and have been reported to be beneficial; however, none have been absolutely satisfactory or optimal for the treatment of all keloid subtypes to date. This poses a major challenge to clinicians. Often, a combinational therapeutic approach appears to offer the best results with higher patient satisfaction compared to monotherapy. The aetiopathogenesis of keloids is not fully elucidated; however, with recent advances in molecular biology and genetics, insight is being gained on the complex process of scar formation and hence new therapeutic and management options for keloids. In this paper, we explore the literature and summarise the general concepts surrounding keloid development and review both current (corticosteroids, surgical excision, silicone-based products, pressure therapy, radiotherapy, cryotherapy, laser therapy, imiquimod and 5-fluorouracil) and emerging (stem cell therapy, mitomycin C, verapamil, interferons, bleomycin, botulinum toxin type A and angiotensin-converting enzyme inhibitors) treatments. Increased knowledge and understanding in this area may potentially lead to the discovery and development of novel therapeutic options that are more efficacious for all keloid types.

LAY SUMMARY

Keloids are problematic scars that are difficult to treat and manage. The aetiopathogenesis of keloids is not clear; however, recent advances in molecular biology and genetics are beginning to shed light on the underlying mechanisms implicated in keloid scar formation which will hopefully lead to the development of treatment options for all keloid types. This review summarises current and emerging therapies.

HIF-1α promotes the keloid development through the activation of TGF-β/Smad and TLR4/MyD88/NF-κB pathways

A keloid is defined as an overgrowth of the dense fibrous tissues that form around a wound. Since they destroy the vascular network, keloid tissues often exhibit anoxic conditions. Hypoxia-inducible factor-1α (HIF-1α) is a core factor that mediates hypoxia stress responses and regulates the hypoxic cellular and biological behaviors. In this study, we found that the expression level of HIF-1α in keloid tissue was significantly higher than that in the normal skin tissue. Hypoxia-induced HIF-1α expression significantly inhibited cellular apoptosis and promoted cellular proliferation in keloid fibroblasts but not in normal fibroblasts. Specifically, HIF-1α activated the TGF-β/Smad and TLR4/MyD88/NF-κB pathways, and the interaction of these two pathways may promote the development of keloids. Moreover, in vivo experiments showed that the inhibition of HIF-1α significantly reduced the growth of keloids.

CUDC‑907 reverses pathological phenotype of keloid fibroblasts in vitro and in vivo via dual inhibition of PI3K/Akt/mTOR signaling and HDAC2

Keloids are benign skin tumors with a high recurrence rate following surgical excision. Abnormal intracellular signaling is one of the key mechanisms involved in its pathogenesis. Over-activated phosphoinositide 3-kinase/RAC-alpha serine/threonine-protein kinase/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway and overproduction of histone deacetylases 2 (HDAC2) have also been observed in keloid fibroblasts (KFs). The present study aimed to explore the possibility of reversing the KF pathological phenotype using CUDC-907, a dual inhibitor of PI3K/Akt/mTOR pathway and HDACs. KFs and keloid xenografts were treated with CUDC-907 to examine its inhibitory effects on the pathological activities of KFs in vitro and in vivo. CUDC-907 inhibited cell proliferation, migration, invasion and extracellular matrix deposition of in vitro cultured KFs and also suppressed collagen accumulation and disrupted the capillaries of keloid explants ex vivo and in vivo. A mechanistic study of CUDC-907 revealed the initiation of cell cycle arrest at G2/M phase along with the enhanced expression of cyclin-dependent kinase inhibitor 1 and decreased expression of cyclin B in cells treated with CUDC-907. CUDC-907 not only inhibited AKT and mTOR phosphorylation and promoted the acetylation of histone H3, but also significantly inhibited the phosphorylation levels of Smad2/3 and Erk. These preclinical data demonstrating its anti-keloid effects suggest that CUDC-907 may represent a candidate drug for systemic keloid therapy.

Understanding Keloid Pathobiology From a Quasi-Neoplastic Perspective: Less of a Scar and More of a Chronic Inflammatory Disease With Cancer-Like Tendencies

Keloids are considered as benign fibroproliferative skin tumors growing beyond the site of the original dermal injury. Although traditionally viewed as a form of skin scarring, keloids display many cancer-like characteristics such as progressive uncontrolled growth, lack of spontaneous regression and extremely high rates of recurrence. Phenotypically, keloids are consistent with non-malignant dermal tumors that are due to the excessive overproduction of collagen which never metastasize. Within the remit of keloid pathobiology, there is increasing evidence for the various interplay of neoplastic-promoting and suppressing factors, which may explain its aggressive clinical behavior. Amongst the most compelling parallels between keloids and cancer are their shared cellular bioenergetics, epigenetic methylation profiles and epithelial-to-mesenchymal transition amongst other disease biological (genotypic and phenotypic) behaviors. This review explores the quasi-neoplastic or cancer-like properties of keloids and highlights areas for future study.

Dissolving Triamcinolone-Embedded Microneedles for the Treatment of Keloids: A Single-Blinded Intra-Individual Controlled Clinical Trial

INTRODUCTION

Keloids are a prevalent chronic skin disorder with significant psychosocial morbidity. Intralesional corticosteroid injections are the first-line treatment but are painful and require repeated injections by medical professionals. Dissolving microneedles are a novel method of cutaneous drug delivery that induces minimal/no pain and can be self-administered. The objective of the study was to evaluate the efficacy and safety of triamcinolone-embedded dissolving microneedles in treatment of keloids.

METHODS

This was a single-blind, intra-individual controlled two-phase clinical trial of 8-week duration each. Two keloids per subject were selected for (1) once-daily 2-min application with microneedles for 4 weeks, followed by no treatment for the next 4 weeks, or (2) non-intervention as control. Primary outcome was change in keloid volume as assessed by a high-resolution 3D scanner.

RESULTS

There was significant reduction in keloid volume compared with controls after 4 weeks of treatment. This reduction was greater with a higher dosage of triamcinolone used.

CONCLUSIONS

Once-daily application of dissolving triamcinolone-embedded microneedles significantly reduced the volume of keloids. The treatment was safe, can be self-administered and can serve as an alternative for patients unsuitable for conventional treatments.

TRIAL REGISTRATION

Trial Registry: Health Science Authority (Singapore) Clinical Trials Register Registration number: 2015/00440.

Application of the Lalonde (horizontal-only scar) breast reduction technique for correction of gynaecomastia in dark skinned patients

Surgical correction of gynaecomastia correction sometimes necessitates skin reduction in addition to resection of glandular tissue and liposuction of the fat deposits. Many skin reduction techniques have been described but all suffer from very noticeable and often poor scars that can manifest as hypertrophic or keloid scars in patients with dark skin. Three large gynaecomastia patients undergoing a modification of the Lalonde "no vertical scar" breast reduction technique designed to reduce the extent of scarring were reviewed. The Lalonde "no vertical scar" technique was successfully applied to three patients of African extraction with acceptable postoperative scarring. A description of the technique and the cosmetic results are presented. The Lalonde technique of female breast reduction can be applied to the treatment of male breast enlargement in patients at high risk of scar complications. It provides an alternative to the more widely used concentric skin reduction techniques. To our knowledge, this is the first report in literature of the application of the Lalonde "no vertical scar" surgical technique to the treatment of gynaecomastia in patients with darkly pigmented skin.

Unraveling the molecular and cellular mechanisms of stretch marks

BACKGROUND

Striae distensae, commonly known as stretch marks, are cutaneous lesions that accompany the hormonal upheavals of the major stages of life: puberty and pregnancy. Stretch marks occur in 90% of women, and they appear as red or purple lines that slowly fade to pale lines on the skin. There have been few studies regarding stretch mark origins, and new preventive and corrective treatments are needed.

AIMS

The aim of this work was to understand the primary genes and proteins involved in the regulation of striae compared to normal skin and to identify the differentially expressed genes and biochemical aspects of SA and SR Importantly, this is the first published study to use a molecular high-throughput approach combined with in vivo evaluation.

METHODS

In this study, we analyzed the molecular differences between skin with and without stretch marks (rubra [SR] and alba [SA]) of female volunteers using DNA microarray (Whole Human Genome Microarray Kit, 4×44 K, Agilent Technologies) analyses of cutaneous biopsies (2 mm) and in vivo confocal Raman spectroscopy of selected buttock regions, a technique recently introduced as a noninvasive skin evaluation method.

RESULTS

We identified gene expression alterations related to ECM, cellular homeostasis, and hormones such as secretoglobulins. Spectral analyses of collagen, fibrillin, and glycosaminoglycans were conducted by Raman spectroscopy at different skin depths. The main differences observed when comparing skin with and without stretch marks were at depths between 75 and 95 μm, corresponding to the dermal-epidermal junction and dermis regions and showing differences between normal skin and stretched skin regarding collagen, collagen hydration, and elastin fibers.

CONCLUSION

The results obtained by RNA and protein analyses are complementary and show that significant changes occur in the skin affected by stretch marks. These results suggest new strategies and opportunities to treat this skin disorder and for the development of new and eficiente cosmetic products.