Novel Insights on Understanding of Keloid Scar: Article Review

Comprehensive analysis of keloid vasculature by tissue clearing and 3D imaging

Keloids are a complex type of scar tissue formed by exaggerated wound healing, characterised by the overgrowth of thick fibrous tissue beyond the original wound boundary. While the crucial relationship between keloid formation and the vascular system has been highlighted, conflicting findings have been reported regarding the characterisation of keloid vasculature. Here, we successfully characterised the detailed three-dimensional (3D) structure of vasculature in keloid tissues using tissue clearing methods combined with 3D imaging. First, we compared two optical tissue clearing methods, the clear, unobstructed brain imaging cocktails and computational analysis and immunolabelling-enabled 3D imaging of solvent-cleared organ protocols, and found the latter to provide greater transparency of keloid scars. We then conducted a detailed 3D vascular analysis using light sheet and confocal fluorescence microscopy. In normal skin, capillary loops and the superficial vascular plexus were located in the papillary layer and at the boundary between the papillary and reticular layers, respectively. However, the density of these vessels was higher in keloid scars than in normal skin. The reticular layer of normal skin exhibited fewer blood vessels. In contrast, keloid scars exhibited significantly thickened dermal reticular layers, with the upper reticular layer showing significantly greater vascularisation. The lower reticular layer of keloid scars also exhibited vertically aligned blood vessels, although their density was lower than in the upper reticular layer. These results indicate that excessive vascularisation is predominantly induced in the papillary and upper reticular layers of keloid scars, which might contribute to keloid pathogenesis. The technique described here has the potential to serve as a crucial template for future pathological analyses of abnormal scars.

ERG transcriptionally activates SFRP1 to promote apoptosis of keloid fibroblasts and inhibit epithelial-mesenchymal transition and fibrosis through the Wnt3a/β-catenin pathway

Keloids are benign skin tumors characterized by excessive fibrosis. Secreted frizzled-related protein 1 (SFRP1) has been linked to fibrosis regulation. Understanding SFRP1's role in keloid fibroblasts (KFs) could provide insights into the molecular mechanisms driving keloid progression and offer new therapeutic avenues. mRNA expression of SFRP1 and ETS-related gene 1 (ERG) was assessed via quantitative real-time polymerase chain reaction. Protein levels were determined by Western blotting. Cell viability was evaluated using cell counting kit-8 assay. Cell apoptosis was detected by flow cytometry. Cell invasion was assessed by transwell assay, and cell migration by wound-healing assay. Chromatin immunoprecipitation and dual-luciferase reporter assays were performed to elucidate the interaction of ERG and SFRP1. SFRP1 was downregulated in keloid tissues and KFs. Overexpression of SFRP1 induced KF apoptosis and inhibited epithelial-mesenchymal transition and fibrosis, concurrent with inactivation of the Wnt3a/β-catenin pathway. ERG was found to transcriptionally activate SFRP1. ERG overexpression promoted KF apoptosis and inhibited epithelial-mesenchymal transition and fibrosis by regulating SFRP1. Wnt3a/β-catenin pathway inactivation. Moreover, the inhibitory effects of ERG overexpression on the protein expression of Wnt3a and β-catenin were attenuated after SFRP1 knockdown. ERG's transcriptional activation of SFRP1 promoted KF apoptosis and inhibited epithelial-mesenchymal transition and fibrosis through the Wnt3a/β-catenin pathway, highlighting a potential therapeutic strategy for keloid management.

Kreotoxin A administration inhibits hyperproliferation and inflammation of human ear keloid tissue and keloid-derived fibroblasts by downregulating HIF-1α expression

Keloids represent a prevalent dermal fibroproliferative disorder. They only affect humans and exhibit several tumor characteristics, such as excessive extracellular matrix (ECM) deposition, which usually occurs after skin injury. Kreotoxin type A (KTA) can inhibit the release of acetylcholine, and thereby inhibit the proliferation of keloid fibroblasts and reducing the formation of scars. Thus, KTA could be used as a therapeutic agent for keloids. However, the mechanisms of action of KTA in keloid treatment remain unclear. In this study, we aimed to explore the underlying mechanisms of action of KTA in human keloid treatment using human tissue and a cell-based model. Integrative microarray analysis revealed that hypoxia-inducible factor 1-alpha (HIF-1α) expression was frequently upregulated in hypertrophic scar and keloid tissues, whereas it was downregulated in the KTA-treated samples. Furthermore, KTA addition to keloid-derived fibroblasts (KDFs) reduced the growth rate and viability, induced apoptosis, and decreased inflammation and oxidative stress in KDFs. However, overexpression of HIF-1α restored cell number and survival, decreased apoptosis, and promoted inflammation and oxidative stress in KTA-treated KDFs. Furthermore, KTA treatment reduced the expression of ECM proteins, including vascular endothelial growth factor (VEGF), collagen I and III, whereas HIF-1α overexpression abolished the effects of KTA on KDFs. In conclusion, our findings provide novel insights into the mechanisms of action of KTA as a potential therapeutic agent for keloids via modulating HIF-1α expression.

Enhanced bioenergetic cellular activity with metabolic switch to aerobic glycolysis in Keloid and Folliculitis Keloidalis Nuchae

Keloid scars and folliculitis keloidalis nuchae (FKN) are benign fibroproliferative dermal lesions of unknown aetiology and ill-defined treatment, which typically present in genetically susceptible individuals. Their pathognomonic hallmarks include local aggressive invasive behaviour plus high recurrence post-therapy. In view of this, we investigated proliferative and key parameters of bioenergetic cellular characteristics of site-specific keloid-derived fibroblasts (intra(centre)- and peri(margin)-lesional) and FKN compared to normal skin and normal flat non-hypertrophic scar fibroblasts as negative controls.The results showed statistically significant (P < 0.01) and variable growth dynamics with increased proliferation and migration in keloid fibroblasts, while FKN fibroblasts showed a significant (P < 0.001) increase in proliferation but similar migration profile to controls. A statistically significant metabolic switch towards aerobic glycolysis in the fibroblasts from the disease conditions was noted. Furthermore, an increase in basal glycolysis with a concomitant increase in the cellular maximum glycolytic capacity was also demonstrated in perilesional keloid and FKN fibroblasts (P < 0.05). Mitochondrial function parameters showed increased oxidative phosphorylation in the disease conditions (P < 0.05) indicating functional mitochondria. These findings further suggest that Keloids and FKN demonstrate a switch to a metabolic phenotype of aerobic glycolysis. Increased glycolytic flux inhibition is a potential mechanistic basis for future therapy.

Long Non-Coding RNA B3GALT5-AS1 Suppresses Keloid Progression by Regulating the β-Trcp1-Mediated Ubiquitination of HuR

Background

lncRNA β‑1,3‑galactosyltransferase 5‑AS1 (B3GALT5-AS1) plays a vital regulatory role in colon and gastric cancers. However, the biological functions and regulatory mechanisms of B3GALT5-AS1 in keloid progression remain unknown. This study aims to investigate the molecular mechanisms in the B3GALT5-AS1-regulated keloid proliferation and invasion.

Methods

Secondary mining of the lncRNA sequencing data from GSE158395 was conducted to screen differentially expressed lncRNAs between keloid and normal tissues. MTT, cell migration and invasion assays were performed to detect the effects of B3GALT5-AS1 on keloid fibroblasts (KFs) proliferation and metastasis. The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were also determined to evaluate glycolysis in KFs. RNA pull-down and RNA-protein immunoprecipitation assays were used to confirm the interaction between B3GALT5-AS1 and Hu-Antigen R (HuR). Further ubiquitination and rescue experiments were performed to elucidate the regulatory relationship between B3GALT5-AS1 and HuR.

Results

B3GALT5-AS1 was significantly down-regulated in keloid tissues and fibroblasts. B3GALT5-AS1 overexpression significantly inhibited KFs proliferation, glycolysis, invasion, and migration and promoted cell apoptosis, whereas silencing B3GALT5-AS1 inhibited these effects. Moreover, B3GALT5-AS1 binds to HuRand reduces its stability through β-Transducin repeats-containing protein 1 (β-Trcp1)-mediated ubiquitination. Overexpression of HuR reversed the inhibition of B3GALT5-AS1 on cell proliferation, migration, and invasion in KFs, where glycolysis pathway was involved.

Conclusion

Our findings illustrate that B3GALT5-AS1 has great effect on inhibition of keloid formation, which provides a potential target for keloid therapy.

Comprehensive Analysis of Current Treatment Approaches for Keloids in Pediatrics: A Systematic Review

Keloids, benign fibrous growths resulting from atypical skin responses to injuries, present a complex challenge in dermatology. These lesions, characterized by excessive collagen production, often lead to physical discomfort and psychological distress. While various treatment methods exist, the lack of a universally effective modality underscores the need for a systematic evaluation of current approaches. This systematic review aims to comprehensively analyze the current available treatment modalities used for the management of keloids in the pediatric population in terms of their effectiveness, safety, and quality of life outcomes. The review adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search was conducted on PubMed and Google Scholar databases to identify relevant studies published in English. The review specifically focused on randomized controlled trials involving patients under 18 diagnosed with keloids, assessing different treatment modalities, and reporting validated measures of treatment efficacy, safety outcomes, and quality of life. The risk of bias was assessed using Cochrane's Risk of Bias Tool for randomized studies to ensure the methodological quality of the included trials. Four studies met the inclusion criteria, collectively involving 196 pediatric patients. Treatment interventions included glucocorticosteroid and fusidic acid cream with silicone gel patches, botulinum toxin type A injections, and Scarban silicone gel sheets. Patient-reported outcomes exhibited varying degrees of improvement in scar size, vascularity, and pliability. Complications, such as rash and wound infection, were reported in some cases. Based on our review of the selected studies and due to the incompletely understood pathogenesis of keloids, there is an ongoing lack of universally effective treatment modality for the management of keloids resulting in their persistently high recurrence rate.

Defining a Unique Gene Expression Profile in Mature and Developing Keloids

Keloids are benign, fibroproliferative dermal tumors that typically form owing to abnormal wound healing. The current standard of care is generally ineffective and does not prevent recurrence. To characterize keloid scars and better understand the mechanism of their formation, we performed transcriptomic profiling of keloid biopsies from a total of 25 subjects of diverse racial and ethnic origins, 15 of whom provided a paired nonlesional sample, a longitudinal sample, or both. The transcriptomic signature of nonlesional skin biopsies from subjects with keloids resembled that of control skin at baseline but shifted to closely match that of keloid skin after dermal trauma. Peripheral keloid skin and rebiopsied surrounding normal skin both showed upregulation of epithelial-mesenchymal transition markers, extracellular matrix organization, and collagen genes. These keloid signatures strongly overlapped those from healthy wound healing studies, usually with greater perturbations, reinforcing our understanding of keloids as dysregulated and exuberant wound healing. In addition, 219 genes uniquely regulated in keloids but not in normal injured or uninjured skin were also identified. This study provides insights into mature and developing keloid signatures that can act as a basis for further validation and target identification in the search for transformative keloid treatments.

Extracellular vesicles from Lactobacillus druckerii inhibit hypertrophic scar fibrosis

BACKGROUND

Hypertrophic scars (HS) affect millions of people each year and require better treatment strategies. Bacterial extracellular vesicles (EVs) are advantaged by low cost and high yield which was commonly used in the treatment of diseases. Here, we investigated the therapeutic efficacy of EVs obtained from Lactobacillus druckerii in hypertrophic scar. In vitro, the effects of Lactobacillus druckerii-derived EVs (LDEVs) on Collagen I/III and α-SMA in fibroblasts obtained from HS. In vivo, a scleroderma mouse model was used to investigate the effects of LDEVs on fibrosis. The impact of LDEVs on excisional wound healing was explored. The different proteins between PBS and LDEVs treated fibroblasts derived from hypertrophic scar were studied by untargeted proteomic analysis.

RESULTS

In vitro, LDEVs treatment significantly inhibited the expression of Collagen I/III and α-SMA and cell proliferation of fibroblasts derived from HS. In vivo, LDEVs withdrawn the hypertrophic scar formation in scleroderma mouse model and decreased the expression of α-SMA. LDEVs promoted the proliferation of skin cells, new blood vessel formation and wound healing in excisional wound healing mice model. Moreover, proteomics has shown that LDEVs inhibit hypertrophic scar fibrosis through multiple pathways.

CONCLUSIONS

Our results indicated that Lactobacillus druckerii-derived EVs has the potential application in the treatment of hypertrophic scars and any other fibrosis diseases.

Therapeutic properties and pharmacological activities of asiaticoside and madecassoside: A review

Centella asiatica is an ethnomedicinal herbaceous species that grows abundantly in tropical and sub-tropical regions of China, India, South-Eastern Asia and Africa. It is a popular nutraceutical that is employed in various forms of clinical and cosmetic treatments. C. asiatica extracts are reported widely in Ayurvedic and Chinese traditional medicine to boost memory, prevent cognitive deficits and improve brain functions. The major bioactive constituents of C. asiatica are the pentacyclic triterpenoid glycosides, asiaticoside and madecassoside, and their corresponding aglycones, asiatic acid and madecassic acid. Asiaticoside and madecassoside have been identified as the marker compounds of C. asiatica in the Chinese Pharmacopoeia and these triterpene compounds offer a wide range of pharmacological properties, including neuroprotective, cardioprotective, hepatoprotective, wound healing, anti-inflammatory, anti-oxidant, anti-allergic, anti-depressant, anxiolytic, antifibrotic, antibacterial, anti-arthritic, anti-tumour and immunomodulatory activities. Asiaticoside and madecassoside are also used extensively in treating skin abnormalities, burn injuries, ischaemia, ulcers, asthma, lupus, psoriasis and scleroderma. Besides medicinal applications, these phytocompounds are considered cosmetically beneficial for their role in anti-ageing, skin hydration, collagen synthesis, UV protection and curing scars. Existing reports and experimental studies on these compounds between 2005 and 2022 have been selectively reviewed in this article to provide a comprehensive overview of the numerous therapeutic advantages of asiaticoside and madecassoside and their potential roles in the medical future.

ADAM17 regulates the proliferation and extracellular matrix of keloid fibroblasts by mediating the EGFR/ERK signaling pathway

To investigate the role of a disintegrin and metalloprotease protein 17 (ADAM17) in regulating the proliferation and extracellular matrix (ECM) expression of keloid fibroblasts (KFs) via the epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) pathway. ADAM17 expression in keloid tissues was detected by western blotting. KFs were isolated, cultured and divided into the control, shNC (negative control), shADAM17, transforming growth factor-β1 (TGF-β1), TGF-β1 + shNC and TGF-β1 + shADAM17 groups. The expression of ECM was detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Western blotting was performed to detect the expression of proteins. Cell proliferation was detected by a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, while cell invasion and migration were examined by Transwell and wound healing assays. The expression of ADAM17 was increased in keloid tissues and KFs. Compared with the control group, the expression of p-EGFR and p-ERK/1/2/ERK1/2, as well as the expression of collagen I, collagen III, connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA), were decreased in KFs from the shADAM17 group, with decreased cell proliferation, invasion and migration. In contrast, the TGF-β1 group presented the opposite trend in these aspects. In addition, compared with the TGF-β1 group, KFs from the TGF-β1 + shADAM17 group had decreased ECM expression, proliferation, invasion and migration. ADAM17 expression was upregulated in keloid tissues. Silencing ADAM17 may inhibit the activity of the EGFR/ERK pathway to limit the deposition of ECM in KFs with reduced proliferation, invasion and migration.

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

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

The effects of mechanical force on fibroblast behavior in cutaneous injury

Wound healing results in the formation of scar tissue which can be associated with functional impairment, psychological stress, and significant socioeconomic cost which exceeds 20 billion dollars annually in the United States alone. Pathologic scarring is often associated with exaggerated action of fibroblasts and subsequent excessive accumulation of extracellular matrix proteins which results in fibrotic thickening of the dermis. In skin wounds, fibroblasts transition to myofibroblasts which contract the wound and contribute to remodeling of the extracellular matrix. Mechanical stress on wounds has long been clinically observed to result in increased pathologic scar formation, and studies over the past decade have begun to uncover the cellular mechanisms that underly this phenomenon. In this article, we will review the investigations which have identified proteins involved in mechano-sensing, such as focal adhesion kinase, as well as other important pathway components that relay the transcriptional effects of mechanical forces, such as RhoA/ROCK, the hippo pathway, YAP/TAZ, and Piezo1. Additionally, we will discuss findings in animal models which show the inhibition of these pathways to promote wound healing, reduce contracture, mitigate scar formation, and restore normal extracellular matrix architecture. Recent advances in single cell RNA sequencing and spatial transcriptomics and the resulting ability to further characterize mechanoresponsive fibroblast subpopulations and the genes that define them will be summarized. Given the importance of mechanical signaling in scar formation, several clinical treatments focused on reducing tension on the wound have been developed and are described here. Finally, we will look toward future research which may reveal novel cellular pathways and deepen our understanding of the pathogenesis of pathologic scarring. The past decade of scientific inquiry has drawn many lines connecting these cellular mechanisms that may lead to a map for the development of transitional treatments for patients on the path to scarless healing.

The Efficacy of Combination Therapy Involving Excision Followed by Intralesional 5-Fluorouracil and Betamethasone, and Radiotherapy in the Treatment of Keloids: A Randomized Controlled Trial

Background

Combined therapy for keloids is currently recommended. Surgery is one of the main options, but the measures to prevent recurrence after excision are still being explored.

Objective

The randomized controlled study aimed at evaluating the efficacy of excision followed by intralesional low concentrations of 5-fluorouracil (5-FU)(12.5 mg/mL) and betamethasone.

Methods

Sixty patients were randomly assigned to three groups. Patients in group A had excision followed by 5-FU and betamethasone intralesional injections, group B had 5-FU and betamethasone intralesional injections, and group C had excision followed by radiotherapy. Efficacy parameters were assessed from 8 to 12 months, including improvement on the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Scale (POSAS), as well as side effects and recurrence. Trial registration number: ChiCTR2100046025.

Results

After 4 months' treatment, the improvement of the VSS and POSAS scores in group A was not different from that in group C (P > 0.05) but was superior to that in group B (P < 0.05); the pain and pruritus of the three groups were relieved more than 50%. After 8 to 12 months' follow-up, there was no statistical difference in the incidence of side effects and recurrence among the groups (P > 0.05).

Conclusion

Excision followed by intralesional low concentrations of 5-FU (12.5mg/mL) with betamethasone is a safe and sustainable treatment for keloid, with no significant difference from excision followed by radiotherapy.

A Signature of Genes Featuring FGF11 Revealed Aberrant Fibroblast Activation and Immune Infiltration Properties in Keloid Tissue

Keloid is a fibroproliferative disorder in the skin, which manifested with extensive deposition of collagen and extracellular matrix. Its etiology remains a mystery and its recurrence rate remains high despite combinative treatment regimens. Current hypotheses of its pathogenesis centered on the role of inflammatory processes as well as immune infiltration in the microenvironment. However, there are a lot of discrepancies when it comes to the verification of certain well-recognized pathways involved in the dysfunctional fibroblast. Further exploration and characterization are required to reveal the driving force and even leading genes responsible for keloid formation. In this study, we provided supportive evidence of the immunologic nature of keloids distinct from normal fibroblasts and physiological scars by incorporating multiple available expressional profiles in the Gene Expression Omnibus (GEO). Through differential analyses and functional analyses, we identified a set of genes that successfully captures the dissimilarities between keloid lesions and nonlesions. They were differentially regulated in keloid samples and had opposite behavior in exposure to hydrocortisone. A key signature of six genes featuring FGF11 not only was highly correlated with significantly dysregulated fibroblast activation but also reflected various levels of immune cell infiltration. FGF11, in particular, revealed the heterogenous immunologic nature of keloid lesions. This study further supported that aberrant fibroblast was one of the main contributing factors and shed some light on investigating immune properties in future studies.

Targeting the Akt/PI3K/mTOR signaling pathway for complete eradication of keloid disease by sunitinib

Keloid disease is a nodular lesion, tumor-like but not cancerous, and characterized of excessive proliferation of fibroblasts and deposition of extracellular matrix (ECM) components. This condition often causes itching, pain and cosmetic disfigurement, significantly reducing patient quality of life. To date, no universally effective therapies are available, possibly due to inadequate understanding of keloid pathogenesis. As an oral small-molecule inhibitor of certain tyrosine kinase receptors, sunitinib has shown significant therapeutic effects in renal cell carcinoma (RCC) and gastrointestinal stromal tumor (GIST). However, it has never been tested if keloid therapy can be effective for the management of keloids. This study thus aims to explore the potential of sunitinib for keloid treatment. Keloid-derived fibroblasts (KFs) were successfully isolated and demonstrated proliferative advantage to normal skin-derived fibroblasts (NFs). Additionally, sunitinib showed specific cytotoxicity and inhibition of invasion, and induced cell cycle arrest and significant apoptosis in KFs. These effects were accompanied by complete suppression of ECM component expression, including collagen types 1 and 3, upregulation of autophagy-associated LC3B and significant suppression of the Akt/PI3K/mTOR pathway. Moreover, a keloid explant culture model was successfully established and used to test the therapeutic efficacy of sunitinib on keloid formation in nude mice. Sunitinib was found to induce complete regression of keloid explant fragments in nude mice, showing significantly higher therapeutic efficacy than the most commonly used intralesional drug triamcinolone acetonide (TAC). These data suggest that sunitinib effectively inhibits keloid development through suppression of the Akt/PI3K/mTOR pathway and thus can be potentially developed as a monotherapy or combination therapy for the effective treatment of keloid disease.

Circular RNA hsa_circ_0043688 serves as a competing endogenous RNA for microRNA-145-5p to promote the progression of Keloids via Fibroblast growth factor-2

Background

Keloids are benign fibroproliferative skin tumors. Circular RNA (circRNA) hsa_circ_0043688 has been exhibited to the freakishly expressed in keloid tissues. Here, we aimed to investigate the regulatory network of hsa_circ_0043688 in the pathological process of keloid.

Methods

Hsa_circ_0043688, microRNA‐145‐5p (miR‐145‐5p), and Fibroblast growth factor‐2 (FGF2) level were detected using RT‐qPCR. Cell viability, proliferation, apoptosis, invasion, and migration were investigated using Cell Counting Kit‐8 (CCK‐8), 5‐ethynyl‐2′‐deoxyuridine (EdU), flow cytometry, transwell, and wound healing assays, respectively. Western blot analysis of protein levels of FGF2, CyclinD1, Collagen I, and Collagen III. After the prediction of Circinteractome and Starbase, their interaction was verified based on a dual‐luciferase reporter and RIP assays.

Results

Increased hsa_circ_0043688 and FGF2, and decreased miR‐145‐5p in keloids samples and fibroblasts were found. Also, hsa_circ_0043688 absence hindered proliferation, invasion, migration, and boost apoptosis of keloid fibroblasts. In mechanism, hsa_circ_0043688 modulated FGF2 content via sponging miR‐145‐5p.

Conclusion

Hsa_circ_0043688 knockdown inhibited cell growth and metastasis of keloid fibroblasts via miR‐145‐5p/FGF2, providing a new mechanism to understand the keloid progression.

Single-Cell RNA-Sequencing Reveals the Cellular and Genetic Heterogeneity of Skin Scar to Verify the Therapeutic Effects and Mechanism of Action of Dispel-Scar Ointment in Hypertrophic Scar Inhibition

Hypertrophic scarring (HS), caused by excessive fibrosis of injured skin, imposes a psychological burden and creates a source of distress that impairs the quality of life of affected individuals. However, the gold standard for HS treatment has not yet been determined due to the complicated and difficult nature of the routines and procedures involved. Previous studies have indicated that the topical application of certain active components found in traditional Chinese medicines shows potential as a therapeutic alternative for scars. Here, single-cell RNA-sequencing was performed to determine cellular heterogeneity and identify marker genes and mechanisms associated with HS. It was found that fibroblasts comprise the largest proportion of HS cell types. The marker genes that were highly expressed in fibroblasts were extracellular matrix (ECM)-related, whereas ECM-receptor interactions and the transforming growth factor (TGF)-β signalling pathway were also found to be active. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, which was applied to identify the molecular compounds of Dispel-Scar Ointment (DSO), revealed 74 effective chemical components belonging to 14 types of constituents, such as flavonoids, tanshinones, salvianolic acids, glycosides, and phthalides. Furthermore, in vivo studies using rat scar models showed that the topical application of Salvia miltiorrhiza, Ligusticum chuanxiong, peach kernel, safflower, and motherwort exerted beneficial effects on fibroblasts. DSO promoted scar maturation and reduced scar areas, its efficacy being similar to that of topically applied silicone. Functional studies using immunofluorescence staining, western blotting, and quantitative real-time polymerase chain reaction demonstrated that DSO may target the TGF-β/Smad pathway to inhibit collagen synthesis and promote ECM remodelling. However, further in vitro mechanistic research and single-drug prescription studies may be required to identify the specific effective compound or active ingredient of DSO, which would provide more substantial evidence regarding the potential therapeutic value of traditional herbs in HS.

Quality-of-life of people with keloids and its correlation with clinical severity and demographic profiles

Though the impairment of quality of life in individuals with keloids is profound, it has neither been well quantified nor correlated with severity in people with skin of colour. This cross-sectional, questionnaire-based study comprised 110 patients with keloid(s). A physician measured the severity of keloids using the Vancouver Scar scale and impairment of quality of life using the patient-filled Hindi version of Dermatology Life Quality Index questionnaire. The relationship among QoL and severity score as well as with components of demographic data was analysed using SPSS. Our study found the severity of keloid(s) to be moderately but significantly correlated with the quality of life of its sufferers. Individuals with multiple keloids were found to be significantly younger than those with solitary ones. Itching, pain, along with restricted mobility significantly impacted the quality of life as well as severity of keloids. Individuals who had undergone prior treatment were found to have a worse quality of life than the treatment naive. Recurrence was found to be associated with lower scar severity, multiple keloids, and younger age. Increasing age, though associated with greater scar severity, lacked any relationship with the quality of life. Our study also found that individuals with bigger keloids sought treatment earlier and more often. Hyperpigmented keloid(s), more common in individuals with skin of colour, were associated with a significantly worse quality of life as well as a higher scar severity.

Treatment of Keloids: A Meta-analysis of Intralesional Triamcinolone, Verapamil, and Their Combination

Keloids are skin lesions of abnormal and excessive scar proliferation that have no agreed upon gold standard of therapy. Extensive research in this area has shown that both intralesional triamcinolone and verapamil are effective in their treatment.

[Differences of water barrier function between keloid and its surrounding normal skin in patients with keloids and its related mechanism]

Objective: To compare the differences of water barrier function between keloids and its surrounding normal skin in patients with keloids, and to explore the primary mechanism. Methods: A cross-sectional observational study was conducted. From October 2020 to March 2021, 30 patients with keloids who met the inclusion criteria visited Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, including 18 females and 12 males, aged 20-48 years. The transepidermal water loss (TEWL) of their keloids and the surrounding normal skin of the 30 patients were measured by multi probe adapter on the reception day. The keloid tissues and normal skin of 5 patients after keloid repair surgery were processed for hematoxylin-eosin staining to measure the thickness of epidermis. Immunohistochemistry was performed on samples from 3 of those 5 patients to detect the expressions of cytokeratin-10, involucrin, and filaggrin in keloids and normal skin. Data were statistically analyzed with paired sample t test and independent sample t test. Results: On the reception day, the TEWL of keloids of 30 patients was 9.0 (6.9, 13.4) g·m-2·h-1 and the TEWL of the normal skin was 8.1 (6.4, 18.1) g·m-2·h-1, between which the difference was not statistically significant (t=0.44, P>0.05). After keloid repair surgery, the thickness of epidermis in the keloids of 5 patients was (194±44) μm, which was significantly thicker than that of the normal skin (44±11) μm, (t=6.88, P<0.01). Furthermore, increased keratinocytes, lack of normal epidermal ridge structures, and thickened stratum corneum were observed in the keloid area. After keloid repair surgery, the expression level of cytokeratin-10 in keloids was significantly lower than that in normal skin of 3 patients (t=8.50, P<0.01), but there were no statistically significant differences in the expression levels of involucrin or filaggrin between keloids and normal skin (with t values of 0.07 and 0.96, respectively, P>0.05). Conclusions: Keloid tissue from patients with keloids displays increased number of keratinocytes and thickened epidermis. But the water barrier function in keloid area is similar to the surrounding normal skin, suggesting that TEWL may not be the main mechanism lead to the persistent development of keloids.

Use of Adipose Stem Cells Against Hypertrophic Scarring or Keloid

Hypertrophic scars or keloid form as part of the wound healing reaction process, and its formation mechanism is complex and diverse, involving multi-stage synergistic action of multiple cells and factors. Adipose stem cells (ASCs) have become an emerging approach for the treatment of many diseases, including hypertrophic scarring or keloid, owing to their various advantages and potential. Herein, we analyzed the molecular mechanism of hypertrophic scar or keloid formation and explored the role and prospects of stem cell therapy, in the treatment of this condition.

Single-Cell RNA-Sequencing Reveals Lineage-Specific Regulatory Changes of Fibroblasts and Vascular Endothelial Cells in Keloids

Keloids are a benign dermal fibrotic disorder with features similar to malignant tumors. keloids remain a therapeutic challenge and lack medical therapies, which is partially due to the incomplete understanding of the pathogenesis mechanism. We performed single-cell RNA-sequencing of 28,064 cells from keloid skin tissue and adjacent relatively normal tissue. Unbiased clustering revealed substantial cellular heterogeneity of keloid tissue, which included 21 clusters assigned to 11 cell lineages. We observed significant expansion of fibroblast and vascular endothelial cell subpopulations in keloids, reflecting their strong association with keloid pathogenesis. Comparative analyses were performed to identify the dysregulated pathways, regulators and ligand-receptor interactions in keloid fibroblasts and vascular endothelial cells. Our results highlight the roles of TGFβ and Eph-ephrin signaling pathways in both the aberrant fibrogenesis and angiogenesis of keloids. Critical regulators probably involved in the fibrogenesis of keloid fibroblasts, such as TWIST1, FOXO3 and SMAD3, were identified. TWIST1 inhibitor harmine could significantly suppress the fibrogenesis of keloid fibroblasts. In addition, tumor-related pathways were activated in keloid fibroblasts and vascular endothelial cells, which may be responsible for the malignant features of keloids. Our study put insights into the pathogenesis of keloids and provides potential targets for medical therapies.

[Several problems worthy of attention in non-surgical treatment of scar]

Pathologically, scars are divided into physiological scars and pathological scars, and the latter mainly include hyperplastic scars and keloids. Scar treatment includes surgical treatment and non-surgical treatment, with the pathological scars as the major targets in treatment. Until now, there is no treatment with ideal therapeutic effect. Therefore, new therapeutic methods for pathological scars are still being explored at home and abroad. In recent years, some non-surgical therapeutic methods for scars that have received widespread attention have emerged. In this article, several problems worthy of attention including intralesional injection therapy, photoelectric therapy, and rehabilitation robots were discussed.

Lnc-H19 enhances anaerobic glycolysis of keloid fibroblasts by targeting the miR-214-5p/FGF2 axis

Long non-coding RNA (lncRNA) H19 has been demonstrated as vital regulator in tumors. However, whether lnc-H19 mediated the development of keloid fibroblasts (KD) was unknown, this study was aimed to clarify the role and molecular mechanisms of lnc-H19 in KD. We have investigated the expression levels of lnc-H19, miR-214-5p and fibroblast growth factor 2 (FGF2) in KD skin samples and normal skin tissues as well as matched cells by real-time quantitative polymerase chain reaction (RT-qPCR) assay. The glycolysis ability of keloid fibroblasts was assessed by measuring glucose consumption, lactate production, and ATP level. The western blot assay was used to assay the expression levels of FGF2 and hexokinase 2 (HK2). Migration and invasion were analyzed by transwell in keloid fibroblasts. The bioinformatics database and dual-luciferase reporter assay were used to search and identify the target of miR-214-5p and lnc-H19. Lnc-H19 was overexpressed in KD tissues and keloid fibroblasts than normal skin tissues and normal fibroblasts, respectively. Small interfering RNA of lnc-H19 treatment markedly inhibited glycolysis, migration and invasion of keloid fibroblasts exposed to hypoxia, which was reserved by silencing of miR-214-5p or upregulation of FGF2. Mechanistically, lnc-H19 regulated KD development by regulation of miR-214-5p/FGF2 axis. In summary, lnc-H19 may exert regulatory functions in KD by targeting miR-214-5p/FGF2 axis, further regulated glycolysis, migration and invasion in keloid fibroblasts exposed to hypoxia, which might be a potential marker of KD diagnosis or progression.

The Horse as a Model for the Study of Cutaneous Wound Healing

Significance: Cutaneous wounds are a major problem in both human and equine medicine. The economic cost of treating skin wounds and related complications in humans and horses is high, and in both species, particular types of chronic wounds do not respond well to current therapies, leading to suffering and morbidity. Recent Advances: Conventional methods for the treatment of cutaneous wounds are generic and have not changed significantly in decades. However, as more is learned about the mechanisms involved in normal skin wound healing, and how failure of these processes leads to chronic nonhealing wounds, novel therapies targeting the specific pathologies of hard-to-heal wounds are being developed and evaluated. Critical Issues: Physiologically relevant animal models are needed to (1) study the mechanisms involved in normal and impaired skin wound healing and (2) test newly developed therapies. Future Directions: Similarities in normal wound healing in humans and horses, and the natural development of distinct types of hard-to-heal chronic wounds in both species, make the horse a physiologically relevant model for the study of mechanisms involved in wound repair. Horses are also well-suited models to test novel therapies. In addition, studies in horses have the potential to benefit veterinary, as well as human medicine.

Extracellular Vesicles in Organ Fibrosis: Mechanisms, Therapies, and Diagnostics

Fibrosis is the unrelenting deposition of excessively large amounts of insoluble interstitial collagen due to profound matrigenic activities of wound-associated myofibroblasts during chronic injury in diverse tissues and organs. It is a highly debilitating pathology that affects millions of people globally and leads to decreased function of vital organs and increased risk of cancer and end-stage organ disease. Extracellular vesicles (EVs) produced within the chronic wound environment have emerged as important vehicles for conveying pro-fibrotic signals between many of the cell types involved in driving the fibrotic response. On the other hand, EVs from sources such as stem cells, uninjured parenchymal cells, and circulation have in vitro and in vivo anti-fibrotic activities that have provided novel and much-needed therapeutic options. Finally, EVs in body fluids of fibrotic individuals contain cargo components that may have utility as fibrosis biomarkers, which could circumvent current obstacles to fibrosis measurement in the clinic, allowing fibrosis stage, progression, or regression to be determined in a manner that is accurate, safe, minimally-invasive, and conducive to repetitive testing. This review highlights the rapid and recent progress in our understanding of EV-mediated fibrotic pathogenesis, anti-fibrotic therapy, and fibrosis staging in the lung, kidney, heart, liver, pancreas, and skin.

Correlation of Melanin Content with Collagen Density in Keloid Patients

BACKGROUND: Keloid is a form of wound healing that results from fibrous tissue activity. It can develop beyond the boundaries of the original wound, extends into the dermis layer, and disrupting the appearance. Previously, no studies have revealed a correlation between melanin pigment and keloid. AIM: This research aimed to describe the correlation between melanin concentration and collagen deposition in keloid tissue. MATERIALS AND METHODS: A prospective study conducted through the application of a cross-sectional analytic survey method. The color of the skin was measured using a chromameter, and a histopathologic examination was performed on the skin surrounding the keloid, as well as the keloid tissue. Data were analyzed using a t-test, correlation, and linear regression statistics. RESULTS: The results showed a significant difference between melanin concentration and collagen deposition in the skin surrounding the keloid tissue. No significant difference was observed between melanin concentration in the surrounding skin of keloid and those in the keloid tissue, as well as collagen deposition. Meanwhile, the melanin concentration in the surrounding skin of keloid and keloid tissue had a significant relationship with fibrocytes number. CONCLUSION: There is a significant correlation between melanin concentrations and collagen density in the keloid tissue.

Adiponectin, but Not TGF-β1, CTGF, IL-6 or TNF-α, May Be a Potential Anti-Inflammation and Anti-Fibrosis Factor in Keloid

INTRODUCTION

Numerous studies have elucidated adiponectin as a negative impact on inflammation and tissue fibrosis. However, little is known about the relevance between adiponectin and inflammatory factors in keloid.

METHODS

To clarify whether adiponectin plays a role in the inflammation and fibrosis of keloid, 50 patients with keloid and 50 healthy subjects were enrolled, We examined the serum and mRNA expression levels of adiponectin, TGF-β1, CTGF, IL-6 and TNF-α in normal skin tissues and keloid tissues by ELISA and qPCR, respectively. Correlation analysis between serum concentration of adiponectin with Vancouver Scar Scale (VSS) scores and the age of patients with keloid was evaluated, and the adiponectin concentrations in patients with keloid between different genders were measured. We further examined the effects of adiponectin on TGF-β1 mediated expression of collagen I, FN and MMP-1 in normal fibroblasts (NFs) and keloid fibroblasts (KFs).

RESULTS

We discovered that lower serum concentration and mRNA expression of adiponectin, but higher TGF-β1, CTGF, IL-6 and TNF-α levels were measured in patients with keloid compared with those in normal controls. Furthermore, there was a strong inverse correlation between the serum adiponectin levels and VSS scores in patients with keloid, but not in ages, and there was no statistically difference between different genders. Moreover, adiponectin attenuated TGF-β1 mediated expression of collagen I and FN, and upregulated the expression level of MMP-1 in KFs, but not in NFs. In addition, the inhibitory effect of adiponectin on TGF-β1 was attenuated by AMPK inhibitor Compound C, but not PI3K/Akt inhibitor LY294002.

DISCUSSION

Adiponectin may exert an anti-inflammation and anti-fibrosis role in the development of keloid. One of the underlying mechanisms may be the activation of the AMPK signaling pathway.

Management of keloid scars: noninvasive and invasive treatments

Scars vary from mature linear scars to abnormal excessive scars such as hypertrophic scars and keloid scars. Keloid scars are fibro-proliferative disease entities that reflect an abnormal process of wound healing. They can cause pain, itching, stiffness, and psychological distress, all of which can affect quality of life. Various treatment options have been advocated as ways to prevent and treat keloid scars. These include noninvasive treatments such as use of silicone gel sheeting and compression therapy, and invasive treatments such as intralesional corticosteroid injections, surgery, and radiotherapy. Novel treatments include chemotherapy, immunotherapy, and anti-inflammatory therapies. Unfortunately, keloids continue to pose a significant challenge due to the lack of efficacious treatments. Therefore, clinicians should be familiar with various therapeutic options and apply the most suitable treatment plan for patients. In this review, we introduce the current therapeutic options for the management of keloid scars.

Emerging and Novel Therapies for Keloids: A compendious review

Keloids are abnormal fibroproliferative scars with aggressive dermal growth expanding beyond the borders of the original injury. Different therapeutic modalities, such as corticosteroids, surgical excision, topical silicone gel sheeting, laser therapy, cryotherapy, photodynamic therapy and radiotherapy, have been used to treat keloids; however, none of these modalities has proven completely effective. Recently, researchers have devised several promising anti-keloid therapies including anti-hypertensive pharmaceuticals, calcineurin inhibitors, electrical stimulation, mesenchymal stem cell therapy, microneedle physical contact and ribonucleic acid-based therapies. The present review summarises emerging and novel treatments for keloids. PubMed^® (National Library of Medicine, Bethesda, Maryland, USA), EMBASE (Elsevier, Amsterdam, Netherlands) and Web of Science (Clarivate Analytics, Philadelphia, Pennsylvania, USA) were searched for relevant literature published between January 1987 to June 2020. A total of 118 articles were included in this review. A deeper understanding of the molecular mechanisms underlying keloid scarring pathogenesis would open further avenues for developing innovative treatments.

Treatment of Small Keloids Using Intralesional 5-fluorouracil and Triamcinolone Acetonide versus Intralesional Bleomycin and Triamcinolone Acetonide

BACKGROUND: The aberration of wound healing leads to scar formation in the form of hypertrophic scars and keloids. Various modalities with variable results have been used in the treatment of keloids. OBJECTIVE: We sought to evaluate outcomes in the treatment of small keloids with the combination of intralesional 5-fluorouracil (5-FU) and triamcinolone acetonide versus intralesional bleomycin and triamcinolone acetonide. DESIGN: Sixty clinically diagnosed keloid lesions in 40 patients aged 18 to 60 years were divided equally into Groups A (n=30) and B (n=30). The combination of intralesional 5-FU and triamcinolone acetonide (TAC) was given to Group A and the combination of intralesional bleomycin and triamcinolone acetonide was given to Group B. Treatment was repeated in both groups at three-week intervals until keloid flattening was achieved or a maximum of 10 treatments were completed. Before treatment, the lesions were assessed using the Vancouver Scar Scale and their size was measured using vernier calipers. RESULTS: In Group A, 15 (50%) keloids showed an excellent response, 10 (33.33%) keloids showed a good response, three (10%) keloids showed a fair response, and two (6.66%) keloids showed a poor response. In Group B, 23 (76%) keloids showed an excellent response, three (10%) keloids showed a good response, two (6.66%) keloids showed a fair response, and two (6.66%) keloids showed a poor response. CONCLUSION: Patient response regarding treatment duration, flattening of lesions, improvements in the Vancouver Scar Scale score, and recurrence rates were statistically significant in Group B. A greater improvement in the signs and symptoms of keloids (with respect to cosmetic problems, restriction of movement, and tenderness) was observed in the patients treated with a combination of intralesional bleomycin and triamcinolone acetonide compared to those treated with a combination of intralesional 5-FU and triamcinolone acetonide.

Assessing keloid recurrence following surgical excision and radiation

Keloids are a fibroproliferative disorder that can result from a cutaneous injury to the reticular dermis. Recurrence rates as high as 100% have been reported following surgical excision alone. Consequently, a variety of post-surgical techniques have been employed to prevent keloid recurrence, including the use of radiation. Although numerous studies have shown post-excisional X-rays, electron beam, lasers and brachytherapy can reduce the rate of keloid recurrence, numerous inconsistencies, including a wide range of definitions for keloid recurrence, make it difficult to compare study outcomes. The review aims to examine the various means for defining keloid recurrence in clinical trials involving the use of radiation therapy. Searches of the Cochrane Library and PubMed were performed to identify the available information for post-surgical keloid recurrence following radiation therapy. Each identified study was reviewed for patient follow-up and criteria used to define keloid recurrence. The search results included clinical studies with external beam radiation, brachytherapy and superficial radiation therapy. Many studies did not include a definition of keloid recurrence, or defined recurrence only as the return of scar tissue. Other studies defined keloid recurrence based on patient self-assessment questionnaires, symptoms and scar elevation and changes in Kyoto Scar Scale, Japan Scar Workshop Scale and Vancouver Scar Scale scores. The results of this review indicate keloidectomy followed by radiation therapy provide satisfactory recurrence rates; however, clinical studies evaluating these treatments do not describe treatment outcomes or use different definitions of keloid recurrence. Consequently, recurrence rates vary widely, making comparisons across studies difficult. Keloid recurrence should be clearly defined using both objective and subjective measures.

A Retrospective Registry Study Evaluating the Long-Term Efficacy and Safety of Superficial Radiation Therapy Following Excision of Keloid Scars

BACKGROUND: Surgical treatment of keloid scars is associated with an approximately 70% recurrence rate at the excision site. OBJECTIVE: We sought to assess keloid recurrence rates when superficial radiation therapy (SRT) was applied following surgical excision. METHODS: Medical records were reviewed of subjects treated for keloid scars followed by SRT (SRT-100™; Sensus Healthcare, Boca Raton, Florida) using a biologically effective dose (BED) of 30Gy and for whom the required retrospective data was available. Eligible subjects (N=61) were treated for 96 keloid scars with SRT. Subjects were male (48%) and female (52%) with a mean age of 38.87 years. Subjects were treated for ≥1 keloid scars following removal by sutured excision (93%) or tangential excision with secondary intention technique (7%). Almost all subjects (98%) received BED 30Gy with irradiation scheme of three 6Gy SRT treatments on Days 1, 2 and 3 following surgery. Mean energy of 100KV (73%) or 70KV (27%) were applied. RESULTS: Ten treated keloidectomy sites (10.4%) had recurrences (i.e., presence of any new tissue growth on the surgical scar) within 12 months increasing to 11 (12.7%) at 18 months. Kaplan-Meier survival probability cure rate was 85.6% from 24 months post-SRT treatment onwards. Transient hyperpigmentation was the most frequent adverse event and there were no malignancies in the treatment area during follow-up evaluations. CONCLUSIONS: SRT with a BED value of 30 Gy delivered to keloidectomy excision sites immediately following excision was well-tolerated and resulted in markedly fewer long-term recurrences than reported following keloidectomy alone. Most keloid scar recurrences occurred within one year. There were no malignancies during follow-up evaluations.

Keloids: a review of therapeutic management

Keloid scar formation arises from a disorganized fibroproliferative collagen response that extends beyond the original wound margins because of excessive production of extracellular matrix (ECM). Despite treatment options for keloid scars including medical and surgical therapies, such as intralesional steroid injection and surgical excision, the recurrence rate remains high. Herein we consolidate recently published narrative reviews, systematic reviews, and meta-analyses to provide an overview of updated treatment recommendations for keloidal scar formation. PubMed search engine was used to access the MEDLINE database to investigate updates regarding keloid incidence and treatment. More than 100 articles were reviewed. Keloid management remains a multimodal approach. There continues to be no gold standard of treatment that provides a consistently low recurrence rate; however, the increasing number of available treatments and synergistic combinations of these treatments (i.e., laser-based devices in combination with intralesional steroids, or 5-fluorouracil (5-FU) in combination with steroid therapy) is showing favorable results. Future studies could target the efficacy of novel treatment modalities (i.e., autologous fat grafting or stem cell-based therapies) for keloid management. This review article provides updated treatment guidelines for keloids and discusses insight into management to assist patient-focused, evidence-based clinical decision making.

Nonmuscle Myosin II Activation Regulates Cell Proliferation, Cell Contraction, and Myofibroblast Differentiation in Keloid-Derived Fibroblasts

Objective: Keloid is an abnormal scar that often develops in high-tension skin. It is caused by excessive fibroblast proliferation and collagen deposition. Nonmuscle myosin IIA (NM-IIA) is an important motor protein that regulates the mechanical transduction of cells. However, the role of NM-IIA in keloid pathogenesis remains unclear. Approach: NM-IIA expression was examined and compared in keloid skin and normal skin by immunofluorescence. The organization of smooth muscle actin (SMA)-mediated stress fibers in normal and keloid fibroblasts (NFs and KFs, respectively) were determined. Cell proliferation and cell contractility were measured in fibroblasts derived from normal and keloids. The NM-II pharmacological inhibitor (blebbistatin) and RNA interference were applied to block NM-IIA and investigate its regulatory role in SMA-mediated stress fibers, cell contractility, and cell proliferation after NM-IIA inhibition. Results: NM-IIA expression is increased in keloid tissue. Inhibition of NM-II by blebbistatin or targeting NM-IIA by RNA interference reduced transforming growth factor beta (TGF-β)-mediated SMA-mediated stress fiber formation, cell proliferation, and cell contractility of NFs and KFs. Although TGF-β failed to mediate phosphorylation of myosin light chain (pMLC, the activator of NM-II), pMLC can interact with SMA-mediated stress fiber. Finally, inhibition of NM-II by blebbistatin also reduced NF and KF proliferation after TGF-β stimulation. Innovation: NM-IIA synergizes with TGF-β to regulate fibroblast proliferation, contraction activity, and myofibroblasts differentiation. Conclusion: NM-IIA might be one of the therapeutic targets in keloids.

Monoclonal Antibodies Addressed to Factors of Signalization in Keloid Scars: Opportunities and Areas of Action

The advance of technology has made possible the use of new techniques within medicine for the treatment of diseases; monoclonal antibodies are a clear example of this. Keloid scars are one of the most difficult pathologies to treat due to the high percentage of recidivism, formed by the growth of a scar with benign fibrous tissue in genetically predisposed individuals, resulting from a process of inflammation and abnormal scarring. Monoclonal antibodies, being a line of treatment that has increased over the years, can show a new frontier in the treatment of them by focusing on the signaling that causes it. We review the literature on the signaling mechanisms of keloid scars and the possible monoclonal approach.

Topical delivery of 5-fluorouracil-loaded carboxymethyl chitosan nanoparticles using microneedles for keloid treatment

Keloids are induced by skin injuries such as surgeries, skin piercings, burns, and trauma. The intra-lesional injection of 5-fluorouracil (5-FU) is a promising therapy to treat keloid. However, local 5-FU injections have caused several side effects such as pain at administration and hyperpigmentation. This study suggests a safer and more effective 5-FU delivery system. We used microneedles to treat keloid because this method has the feasibility of self-administration without pain. In this study, 5-FU-loaded carboxymethyl chitosan (CMC) nanoparticles were prepared and characterized by various analytical methods and then coated on stainless solid microneedles. The blank CMC nanoparticles caused an increase in cell viability on human normal fibroblasts to 150%. In particular, the 5-FU-loaded CMC nanoparticles showed a significant inhibitory effect on the human keloid fibroblast to 16%. The intercellular uptake of the 5-FU-loaded CMC nanoparticles was observed on both human normal and keloid fibroblasts by using a confocal microscope. In addition, it was found that the nanoparticles showed an inhibition of TGF-β1 by ELISA. For topical drug delivery, it was confirmed that the nanoparticles coated onto the microneedles were dissolved and diffused at the administration site in the porcine dorsal skin model. According to these results, the suggested microneedle-mediated drug delivery system not only inhibits the human keloid fibroblasts by delivering drugs effectively into the keloids but also has the feasibility to self-administer without pain. Therefore, this new system including 5-FU-loaded CMC nanoparticles and microneedles has the potential to treat keloid scars. Graphical abstract.

RNAi nanotherapy for fibrosis: highly durable knockdown of CTGF/CCN-2 using siRNA-DegradaBALL (LEM-S401) to treat skin fibrotic diseases

Skin fibrosis occurs in a variety of human diseases but the current anti-fibrosis treatments are not sufficient. One major cause of fibrotic diseases shared across diverse organ fibrosis is uncontrolled overexpression of the connective tissue growth factor (CTGF, also known as CCN2). Here, we examine the anti-fibrotic activity of RNAi therapy utilizing siRNA against CTGF with a new drug delivery system (DDS), 'DegradaBALL', which is based on porous nanoparticles, for durable CTGF gene silencing. DegradaBALL is a modular DDS having many favorable properties for RNA delivery such as effective intracellular uptake, convenient drug loading, biocompatibility, sustained release profile and biodegradability. DegradaBALL loaded with siCTGF, named 'LEM-S401', showed highly durable and effective CTGF gene-silencing in TGF-β induced lung fibrosis and skin fibrosis model cells, A549 and HaCaT, respectively. In addition, LEM-S401 induced knockdown of collagen types I and III, which are excess extracellular matrix components in fibrotic skin in addition to CTGF in the mouse wound healing model. Most importantly, we showed that LEM-S401 effectively inhibited the formation of hypertrophic scars in wound-associated dermal fibrosis mouse models, during both the epidermis recovery and tissue remodeling process. Our findings suggest that LEM-S401 could be a highly potent therapeutic option for skin fibrotic diseases.

Quantitative Assessment of Keloids Using Ultrasound Shear Wave Elastography

This study was aimed at investigating the value of shear wave elastography (SWE) in quantitative evaluation of keloids. A total of 87 patients with 139 keloids were enrolled. Vancouver scar scale (VSS) scores were recorded. Thickness and blood flow grade were evaluated using high-frequency ultrasound. Skin stiffness (mean speed of shear wave, C_mean) was evaluated using SWE in both transverse and longitudinal sections. All measurements were performed in both keloids and site-matched unaffected skin (normal controls). The reliability of measurements was evaluated using intra- and inter-class correlation coefficients by two observers. Inter- and intra-observer repeatability was excellent (correlation coefficient > 0.99, p < 0.01). The SWE results revealed a significant increase in C_mean in keloids (p < 0.001) compared with the normal controls. C_mean in the longitudinal section was greater than that in the transverse section for keloids (p < 0.001). C_mean was highly positively correlated with VSS score (r = 0.904, p < 0.001), moderately positively correlated with thickness (r = 0.490, p < 0.001) and less positively correlated with blood flow (r = 0.231, p < 0.01). This non-invasive, tolerable and convenient imaging technique could be an effective tool for objectively evaluating keloid stiffness in the future, thus laying a foundation for the treatment and evaluation of keloids.

Expression profile and bioinformatics analyses of circular RNAs in keloid and normal dermal fibroblasts

Increasing evidence indicates that circular RNAs (circRNAs) play a crucial regulatory role in the pathogenesis of multiple diseases. However, no study has examined the potential biological function and expression profile of circRNAs in keloid dermal fibroblasts (KDFs). Therefore, the aim of this study to investigate the expression profile of circRNAs and analyze their role in KDFs. Bioinformatic analyses and high-throughput RNA sequencing technology were applied to explore the expression profile of circRNAs in 3 human KDFs and normal dermal fibroblasts (NDFs). The differentially expressed circRNAs were verified by reverse transcription PCR (RT-PCR), quantitative real-time-PCR (qRT-PCR) and Sanger sequencing. A circRNA-microRNA (miRNA)-mRNA interaction network was created using bioinformatics tools. Hsa_circ_0008259, was selected to confirm its function by qRT-PCR and Western blot. Collectively, 411 circRNAs, of which 206 were upregulated and 205 decreased, were found to be differentially expressed in KDFs and could bind to 2532 miRNA response elements (MREs). GO and KEGG pathways enrichment analyses showed that differentially expressed circRNAs were mainly involved in apoptosis, focal adhesion, PI3K-Akt and metabolic pathway, and may regulate the pathogenesis and development of keloid. Two candidate circRNAs (hsa_circRNA_0008259, hsa_circRNA_0005480) were verified to be significantly reduced in KDFs, and one candidate circRNA (hsa_circRNA_0002198) was significantly elevated in accordance with RNA-Seq data analysis. Overexpression of hsa_circRNA_0008259 inhibited type I and Ⅲ collagen expression. Taken together, our study demonstrates for the first time that circRNAs exhibits differential expression in KDFs, and may be key players in the pathogenesis of keloid, or act as biomarkers of keloid.

The role of macrophages in the formation of hypertrophic scars and keloids

Numerous studies have shown that macrophages can orchestrate the microenvironment from the early stage of wound healing to the later stages of scar formation. However, few reviews have highlighted the significance of macrophages during the formation of abnormal scars. The purpose of this review was to outline the polarization of macrophages from early to late stage of pathological scar formation, focusing on spatiotemporal diversity of M1 and M2 macrophages. In this review, the role of macrophages in the formation of hypertrophic scars and keloids is summarized in detail. First, an increased number of M2 cells observed before injuries are significantly associated with susceptibility to abnormal scar pathogenesis. Second, decreased expression of M1 at the early stage and delayed expression of M2 at the late stage results in pathological scar formation. Third, M2 cells are highly expressed at both the margin and the superficial region, which is consistent with the invasive property of keloids. Finally, this review helps to characterize strategies for the prediction and prevention of pathological scar formation.

The role of pharmacogenetics in keloid scar treatment: A literature review

BACKGROUND

The pathophysiology of keloid scars is still not fully understood and a universally reliable effective treatment has not been identified. Pharmacogenetics explores how drug response to a particular therapy can relate to genetic variations.

PURPOSE

To investigate how pharmacogenetics could be applied to keloid scars and the relevance of this to clinical practice.

METHODS

We reviewed the literature and discuss our current knowledge of pharmacogenomics in the treatment of keloid scars. A literature search was performed using the terms 'Pharmacogenetics', 'Pharmacogenomics', 'Keloid' and 'Scar'. We searched the PubMed, MEDLINE and EMBASE databases to find the relevant articles. Only articles in English were chosen. The level of evidence was evaluated and selected accordingly listing the studies with the highest level of evidence first.

RESULTS

Treatments including corticosteroid injections and 5-fluorouracil can be effective in some patients, but less so in others. Polymorphisms of the glucocorticoid receptor and variants of CCL2, YAP1, miR-21-5p and NF-κβ might be responsible for different responses to treatments used in keloid scars such as 5-fluorouracil. Small molecule inhibitors might be utilised to target other implicated genes.

CONCLUSION

Pharmacogenetics aims to produce the most efficacious patient outcomes while reducing adverse effects. Understanding the pharmacogenetics of keloid scars could lead to a new era of personalised medicine in the treatment of keloid scars. At present, there is some evidence (level 3b/4) to suggest genetic variations that are responsible to drug response in keloids, but further research in this field is required.

LAY SUMMARY

The varied response to similar therapeutic treatments in keloids has prompted the consideration of the role of genetic variants on response in the form of pharmacogenetics. Pharmacogenetics refers to drugs and their metabolism and action based on genetic influences. The ideal scenario would involve the selection of treatment based on the individual's specific genetic variants to ensure maximum efficacy with minimal toxicity. Some evidence currently points to genetic variations in some keloid patients that might be of relevance to the treating clinician.

Long non-coding RNA HOXA11-AS accelerates the progression of keloid formation via miR-124-3p/TGFβR1 axis

Emerging evidence reveals the importance of long non-coding RNAs (lncRNAs) in the development and progression of keloid formation, whereas the underlying mechanisms are not well understood. In the present study, we investigated the biological effects and molecular mechanisms of lncRNA HOXA11-AS in keloid formation. First, the expression levels of HOXA11-AS, miR-124-3p, and transforming growth factor β receptor type I (TGFβR1) were measured in both keloid tissues and human keloid fibroblasts (HKFs) using qRT-PCR and western blot analysis, respectively. Next, we adopted both gain- and loss-of-function strategies to explore the significance of HOXA11-AS. TUNEL, flow cytometry, DNA ladder, and tube formation assays were performed to measure cell apoptosis and angiogenesis, respectively. Besides, the potential binding relationship between HOXA11-AS and miR-124-3p, as well as miR-124-3p and TGFβR1 was identified using bioinformatic screening and verified by luciferase reporter assay. Furthermore, we explored the importance of miR-124-3p in HOXA11-AS-induced phenotypes and regulations on TGFβ signaling or PI3K/Akt signaling. We found that HOXA11-AS and TGFβR1 were significantly up-regulated, while miR-124-3p was down-regulated both in keloid tissues or fibroblasts than in normal skin tissues or fibroblasts. Functionally, high expression of HOXA11-AS essentially inhibited cell apoptosis and promoted fibroblast-induced angiogenesis. Mechanistically, miR-124-3p was identified as a downstream effector to be involved in HOXA11-AS-mediated phenotypes through directly targeting TGFβR1, thus modulating PI3K/Akt signaling pathway. Taken together, our findings revealed that HOXA11-AS inhibits cell apoptosis and promotes angiogenesis through miR-124-3p/TGFβR1 axis, contributing to the progression of keloid formation, which might provide a novel target for keloid therapy.

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.

The influence of GSTT/GSTM null genotypes in scarring

Background and aims

The process of scarring is a common denominator of interest for the medical field. From general medicine to dentistry, pathological scar tissue represents a challenge in providing optimal care to a patient. The present study aims to investigate whether a systemically reduced antioxidant potential, revealed by null isoforms of glutathione S transferase, affects the process of scarring in a group of female patients.

Methods

The study is based on a group of 54 patients with physiological scars after a 6-month observation period, as well as 18 patients with hypertrophic or atrophic scars. Peripheral venous blood was collected, from which DNA was extracted using a commercial kit. Genotyping followed a Multiplex PCR protocol for GSTT1/GSTM1.

Results

In a dominant model, the combination of wild type (heterozygous or homozygous) GSTT1 and GSTM1 was negatively associated with pathological scarring, with the wild type (heterozygous or homozygous) GSTM1 genotype being potentially responsible for this effect. Other factors affecting pathological scarring were investigated: family history, phototype, as well as scores on the POSAS and SCAR scales.

Conclusions

The presence of GSTT1 and GSTM1 alleles brings forward an increased antioxidant capacity, serving as a protective factor for patients during scar formation.

Two Functional TP53 Genetic Variants and Predisposition to Keloid Scarring in Caucasians

Introduction

Keloid is defined as a benign proliferative scar that grows beyond the confines of the original insult to the skin, invading into adjacent normal tissue. The pathogenesis of keloid is complex, and many evidences suggest the influence of genetic factors, among them the polymorphisms of the TP53 gene encoding tumor protein p53.

Objective

To investigate the association of rs1042522 (c.215G>C, p.Arg72Pro) and rs17878362 (16-bp insertion/duplication in intron 3) variants, two most frequently analyzed TP53 functional polymorphisms and the risk of keloid in Polish patients.

Materials and Methods

The rs1042522 and rs17878362 polymorphisms were identified by sequencing genomic DNA extracted from peripheral blood leukocytes of 86 keloid patients and from cordial blood leukocytes of 100 newborn infants consisting control group.

Results

The rs1042522 and rs17878362 TP53 genotype distributions both in keloid patients and in the control group conformed to the expected Hardy–Weinberg equilibrium. No significant differences in the distribution of rs1042522 and rs17878362 TP53 alleles or genotypes have been found between keloid patients and newborn controls. There is tight, but not complete, linkage disequilibrium between rs1042522 and rs17878362 TP53 polymorphisms (D′ = 0.667, r = 0.448, and p=0). No significant differences in the distribution of rs1042522 and rs17878362 TP53 haplotypes or diplotypes have been found between keloid patients and newborn controls.

Conclusions

Our results suggest the lack of association of rs1042522 and rs17878362 TP53 polymorphisms and their haplotypes or diplotypes with the susceptibility to keloid scarring in Polish patients.

Expression of Cathepsins B, D, and G by the Embryonic Stem Cell-Like Population within Human Keloid Tissues and Keloid-Derived Primary Cell Lines

BACKGROUND

The authors have previously shown that an embryonic stem cell-like population within keloid-associated lymphoid tissues in keloid lesions expresses components of the renin-angiotensin system that may be dysregulated. The authors hypothesized that cathepsins B, D, and G are present within the embryonic stem cell-like population in keloid lesions and contribute to bypass loops of the renin-angiotensin system.

METHODS

3,3'-Diaminobenzidine immunohistochemical staining for cathepsins B, D, and G was performed on formalin-fixed paraffin-embedded sections in keloid tissue samples of 11 patients. Immunofluorescence immunohistochemical staining was performed on three of these keloid tissue samples, by co-staining with CD34, tryptase, and OCT4. Western blotting, reverse transcription quantitative polymerase chain reaction, and enzyme activity assays were performed on five keloid tissue samples and four keloid-derived primary cell lines to investigate protein and mRNA expression, and functional activity, respectively.

RESULTS

3,3'-Diaminobenzidine immunohistochemical staining demonstrated expression of cathepsins B, D, and G in all 15 keloid tissue samples. Immunofluorescence immunohistochemical staining showed localization of cathepsins B and D to the endothelium of microvessels within the keloid-associated lymphoid tissues and localization of cathepsin G to the tryptase-positive perivascular cells. Western blotting confirmed semiquantitative levels of cathepsins B and D in keloid tissue samples and keloid-derived primary cell lines. Reverse transcription quantitative polymerase chain reaction showed quantitative transcriptional activation of cathepsins B and D in keloid tissue samples and keloid-derived primary cell lines and cathepsin G in keloid tissue samples. Enzyme activity assays demonstrated functional activity of cathepsins B and D.

CONCLUSION

Cathepsins B, D, and G are expressed by the embryonic stem cell-like population within the keloid-associated lymphoid tissues of keloid lesions and may act to bypass the renin-angiotensin system, suggesting a potential therapeutic target using renin-angiotensin system modulators and cathepsin inhibitors.

Stem cell therapy for chronic skin wounds in the era of personalized medicine: From bench to bedside

With the significant financial burden of chronic cutaneous wounds on the healthcare system, not to the personal burden mention on those individuals afflicted, it has become increasingly essential to improve our clinical treatments. This requires the translation of the most recent benchtop approaches to clinical wound repair as our current treatment modalities have proven insufficient. The most promising potential treatment options rely on stem cell-based therapies. Stem cell proliferation and signaling play crucial roles in every phase of the wound healing process and chronic wounds are often associated with impaired stem cell function. Clinical approaches involving stem cells could thus be utilized in some cases to improve a body's inhibited healing capacity. We aim to present the laboratory research behind the mechanisms and effects of this technology as well as current clinical trials which showcase their therapeutic potential. Given the current problems and complications presented by chronic wounds, we hope to show that developing the clinical applications of stem cell therapies is the rational next step in improving wound care.

TGF-β-induced fibrotic stress increases G-quadruplex formation in human fibroblasts

Scar formation after wound healing is a major medical problem. A better understanding of the dynamic nuclear architecture of the genome during wound healing could provide insights into the underlying pathophysiology and enable novel therapeutic strategies. Here, we demonstrate that TGF-β-induced fibrotic stress increases formation of the dynamic secondary DNA structures called G-quadruplexes in skin fibroblasts, which is coincident with increased expression of collagen 1. This G-quadruplex formation is attenuated by a small molecule inhibitor of intracellular Ca²⁺ influx and an anti-fibrotic compound. In addition, we identify G-quadruplex-forming sequences in the promoter region of COL1A1, which encodes collagen 1, and confirm their ability to form G-quadruplex structures under physiologically relevant conditions. Our findings reveal a link between G-quadruplexes and scar formation that may lead to novel therapeutic interventions.