Scar formation, with persistent alteration of the normal tissue structure, is an undesirable and significant result of both wound healing and fibrosing disorders. There are few strategies to prevent or to treat scarring. The transforming growth factor beta (TGF-β) superfamily is an important mediator of tissue repair. Each TGF-β isoform may exert a different effect on wound healing, which may be context-dependent. In particular, TGF-β1 may mediate fibrosis in adults' wounds, while TGF-β3 may promote scarless healing in the fetus and reduced scarring in adults. Thus, TGF-β3 may offer a scar-reducing therapy for acute and chronic wounds and fibrosing disorders.

Transforming growth factor beta (TGF-β) isoforms in wound healing and fibrosis.

Centella asiatica is a medicinal plant that was already used as a 'panacea' 3000 years ago. The active compounds include pentacyclic triterpenes, mainly asiaticoside, madecasosside, asiatic acid and madecassic acid. We have conducted an overview to summarize current knowledge on the results of scientific in vitro and in vivo experiments focused on the improvement of the healing process of small wounds, hypertrophic scars and burns by C. asiatica. In this paper, we discuss the data on constituents, recommended preparations and the potential side effects of C. asiatica.

Centella asiatica in Dermatology: An Overview

Centella asiatica (CA) is a traditional herbal medicine that has been shown to exert pharmacological effects on wound healing. This study demonstrated that CA extract facilitates the wound-repair process by promoting fibroblast proliferation and collagen synthesis and exhibits antibacterial activity. Gelatin nanofibres containing C. asiatica extract were fabricated via electrospinning and were shown to exhibit dermal wound-healing activity in a rat model. The wound areas of rat skin treated with electrospun gelatin membranes containing C. asiatica (EGC) presented the highest recovery rate compared with those treated with gauze, neat gelatin membranes and commercial wound dressings. The results of the histopathological examination support the outcome of the wound models. Contact-angle and water-retention measurements confirmed that the addition of C. asiatica extract did not significantly affect the hydrophilicity of the EGC membranes. The measured weight loss revealed that the EGC membranes are biodegradable. The findings suggest that EGC membranes are a promising material for the treatment of skin wounds. Copyright © 2015 John Wiley & Sons, Ltd.

Wound-healing effect of electrospun gelatin nanofibres containing Centella asiatica extract in a rat model.

Liver fibrosis is a major cause of liver failure, but treatment remains ineffective. In the present study, we investigated the mechanisms and anti-hepatofibrotic activities of asiatic acid (AA) in a rat model of liver fibrosis induced by carbon tetrachloride (CCl4) and in vitro in TGF-beta1-stimulated rat hepatic stellate cell line (HSC-T6). Treatment with AA significantly attenuated CCl4-induced liver fibrosis and functional impairment in a dosage-dependent manner, including blockade of the activation of HSC as determined by inhibiting de novo alpha smooth muscle actin (a-SMA) and collagen matrix expression, and an increase in ALT and AST (all p<0.01). The hepatoprotective effects of AA on fibrosis were associated with upregulation of hepatic Smad7, an inhibitor of TGF-beta signaling, thereby blocking upregulation of TGF-beta1 and CTGF and the activation of TGF-beta/Smad signaling. The anti-fibrosis activity and mechanisms of AA were further detected in vitro in HSC-T6. Addition of AA significantly induced Smad7 expression by HSC-T6 cells, thereby inhibiting TGF-beta1-induced Smad2/3 activation, myofibroblast transformation, and collagen matrix expression in a dosage-dependent manner. In contrast, knockdown of Smad7 in HSC-T6 cells prevented AA-induced inhibition of HSC-T6 cell activation and fibrosis in response to TGF-beta1, revealing an essential role for Smad7 in AA-induced anti-fibrotic activities during liver fibrosis in vivo and in vitro. In conclusion, AA may be a novel therapeutic agent for liver fibrosis. Induction of Smad7-dependent inhibition of TGF-beta/Smad-mediated fibrogenesis may be a central mechanism by which AA protects liver from injury.

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Asiatic acid inhibits liver fibrosis by blocking TGF-beta/Smad signaling in vivo and in vitro.

Scarring, tightly associated with fibrosis, is a significant symptomatic clinical problem. Interleukin 10 (IL-10) has been identified as a candidate scar-improving therapy based on preclinical studies. However, the molecular mechanism of IL-10 in scar improvement is still uncertain. In this study, human dermal fibroblasts stimulated with TGF-β1 were treated with IL-10 to analyze the mRNA and some of proteins’ expression levels of type I collagen (Col1), type III collagen (Col3), alpha-smooth muscle actin (α-SMA), matrix metalloproteinase-1 (MMP1), MMP2, MMP8 and tissue inhibitor of metalloproteinase 1 (TIMP1), TIMP2 by real-time PCR and Western blot, to observe α-SMA-positive fibroblasts by immunocytochemistry. The contracture and improvement of fibroblast-populated collagen lattice (FPCL) and a murine model of wound healing were used to evaluate the scar-improving effects by histological staining. The results showed that IL-10 can significantly down-regulate the mRNA and protein expression levels of Col1, Col3, α-SMA, and up-regulate the mRNA expression levels of MMP1 and MMP8, and decrease α-SMA-positive fibroblasts. FPCL analysis showed that the IL-10 (20 ng/ml) can significantly inhibit the contracture, improve the architecture of FPCL. Wounds injected with IL-10 demonstrated that the appearance of scar was improved, the wound margin of scarring was narrow, and the deposition of collagens (Col1 and Col3) in regenerated tissue was relieved. These results provide direct evidences that IL-10 has the inhibitory effects on the excessive deposition of extracellular matrix components and fibroblast-to-myofibroblast transition, and show that IL-10 has the potential therapy in prevention and reduction of skin scarring.

Protection against TGF-β1-induced fibrosis effects of IL-10 on dermal fibroblasts and its potential therapeutics for the reduction of skin scarring

Asiaticoside (ATS) isolated from the leaves of Centella asiatica possesses strong wound-healing properties and reduces scar formation. However, the specific effects of asiaticoside on the formation of keloidal scars remain unknown. In the present study, we evaluated the in vitro effects of asiaticoside on the proliferation, collagen expression, and transforming growth factor (TGF)-β/Smad signaling of keloid-derived fibroblasts. Fibroblasts isolated from keloid tissue and normal skin tissues were treated with asiaticoside at different concentrations. Afterwards, they were subjected to RT-PCR and Western blot analyses. The inhibitory effects of asiaticoside on fibroblast viability were assayed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Asiaticoside decreased fibroblast proliferation in a time- and dose-dependent manner. It also inhibited type I and type III collagen protein and mRNA expressions. In addition, asiaticoside reduced the expression of both TGF-βRI and TGF-βRII at the transcriptional and translational level. Moreover, it increased the expression of Smad7 protein and mRNA. However, asiaticoside did not influence the expression of Smad2, Smad3, Smad4, phosphorylated Smad2, and phosphorylated Smad3. Taken together, these results suggest that asiaticoside could be of potential use in the treatment and/or prevention of hypertrophic scars and keloids.

Asiaticoside suppresses collagen expression and TGF-β/Smad signaling through inducing Smad7 and inhibiting TGF-βRI and TGF-βRII in keloid fibroblasts.

Background Although escharectomy and full-thickness skin autografting have been widely used to treat deep facial burns, the clinical outcomes remain unacceptable. Composite razor-thin skin grafting over acellular dermal matrix scaffold has been used successfully in repairing burns of the trunk and limbs, but its use in covering deep facial burns has rarely been reported. In this study, the authors investigated the clinical outcomes of early escharectomy and concurrent composite razor-thin skin autografting and acellular dermal matrix scaffold for treating deep facial burns. Methods Patients with deep facial burns (n = 16) involving 8 to 30 percent of the total body surface area received early escharectomy by postburn day 3 and concurrent, one-stage, large, razor-thin skin autografting on top of human acellular dermal matrix scaffold. Wound dressings were changed on postoperative days 7, 9, and 12 to examine the survival of skin autografts. Patients were followed up for 12 months to evaluate their facial profiles. Results The take rate of composite skin autografts was 97.3 percent at postoperative day 12. At the follow-up visit, the skin autografts appeared normal in color, with soft texture and good elasticity. The skin junctures showed little scarring. The patients exhibited a chubby facial appearance and abundant expression, except for one patient with microstomia and two patients with ectropion who required further plastic surgical interventions. Conclusion Early escharectomy and concurrent composite razor-thin skin autografting on top of acellular dermal matrix scaffold constitute an effective and favorable option for covering deep facial burns, especially for patients with limited donor sites.

Early escharectomy and concurrent composite skin grafting over human acellular dermal matrix scaffold for covering deep facial burns.

Achievement of large magnetostriction in [001]-textured Mn1-Ni CoSi/epoxy composites at room temperature

Objective To investigate and search correlative proteins of keloid by comparing the results of differential proteomic analysis between keloid and normal skin. Methods From January 2010 to June 2010 two-dimensional gel electrophoresis was used to define patterns of protein expression in keloid skin from 8 patients and matched normal skin from 3 patients. Differential expression protein spots were showed and analyzed by matrix-assisted laser desorption ionization-time of flying/time of flying (MALDI-TOF/TOF) mass spectrometry. Results This study succeeded to provide a two-dimensional protein profiling comparison between normal skin and keloid. Gel-analysis software identified an average of 2978 spots in keloid while 3053 spots in normal skin and statistical filtering yielded 40 spots of a 4-fold change, 32 of which were identified by using mass spectrometry, 20 were up-regulated and 12 were down-regulated. Functional analysis revealed that these proteins could be fractionated to carrier proteins (3 proteins), signal transduction proteins (4 proteins), proliferation and apoptosis related proteins (2 proteins), cytoskeleton proteins (6 proteins), extracellular matrix proteins (8 proteins), immunity related proteins (3 proteins), tumor related proteins (2 proteins), and function unknown protein (4 proteins). Conclusions Proteomic analysis can identify the proteins with variance of keloid versus normal skin. The further research to these differential proteins may help reveal the pathogenesis of keloid and provide new treatments for keloid.

Bin Chen

Papers

Asiaticoside suppresses collagen expression and TGF-β/Smad signaling through inducing Smad7 and inhibiting TGF-βRI and TGF-βRII in keloid fibroblasts.

Early escharectomy and concurrent composite skin grafting over human acellular dermal matrix scaffold for covering deep facial burns.

Achievement of large magnetostriction in [001]-textured Mn1-Ni CoSi/epoxy composites at room temperature

Proteomic analysis between keloid and normal skin