New research advances in hypertrophic scar formation, prevention and treatment / 中华预防医学杂志

Scarring, naturally induced by fibroblasts(Fb) during wound healing, is an essential process in response to repair damaged tissue. Excessive Fb proliferation which produces the excessive collagen deposition, including increased extracellular matrix synthesis or insufficient decomposition, typically contributes to hypertrophic scar(HS) formation. Although exact mechanisms of HS are not yet fully understood, it is generally believed that dysfunction of Fb and regulation of signal pathways play an important role in HS formation. Biologically, Fb function is affected by various factors such as cytokines, extracellular matrix and itself. In addition, modifications of miRNA, ceRNA, lncRNA, peptides and histones participate in HS formation by affecting the biological function of Fb. Despite the clinical importance, very few therapeutic modalities are available to prevent HS. To achieve this, a deeper characterization of Fb is required to identify mechanisms of HS. To the aspect of HS prevention and treatment, we review recent findings, concentrating on Fb function and collagen secretion. The objective of this article is to frame the current understanding, gain the deeper insights into Fb function, and provide the more comprehensive cognition and perspective for prevention and treatment of HS.

Regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts / 中华烧伤杂志

Objective: To investigate the regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts (HSFbs). Methods: The experimental research methods were used. The 4th-6th passage of HSFbs from human skin were used for the following experiments. HSFbs were co-cultured with sodium ferulate at final mass concentrations of 1, 1×10-1, 1×10-2, 1×10-3, 1×10-4, 1×10-5, and 1×10-6 mg/mL for 48 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and linear regression was used to analyze the half lethal concentration (LC50) of sodium ferulate (n=6). HSFbs were co-cultured with sodium ferulate at final mass concentrations of 0.1, 0.2, 0.3, and 0.4 mg/mL for 24, 48, 72, and 96 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and the cell proliferation inhibition rate was calculated (n=3). According to the random number table, the cells were divided into 0.300 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, 0.003 mg/mL sodium ferulate group treated with sodium ferulate at corresponding final mass concentrations, and negative control group without any treatment. After 72 hours of culture, the cell absorbance values were determined by methyl thiazolyl tetrazolium method (n=5), the microscopic morphology of cells was observed by transmission electron microscope (n=3), the cell apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay and the apoptosis index was calculated (n=4), the protein expressions of B lymphocystoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and cysteine aspartic acid specific protease-3 (caspase-3) were determined by immunohistochemistry (n=4), and the protein expressions of transformed growth factor β1 (TGF-β1), phosphorylated Smad2/3, phosphorylated Smad4, and phosphorylated Smad7 were detected by Western blotting (n=4). Data were statistically analyzed with one-way analysis of variance and Dunnett test. Results: The LC50 of sodium ferulate was 0.307 5 mg/mL. After being cultured for 24-96 hours, the cell proliferation inhibition rates of cells treated with sodium ferulate at four different mass concentrations tended to increase at first but decrease later, which reached the highest after 72 hours of culture, so 72 hours was chosen as the processing time for the subsequent experiments. After 72 hours of culture, the cell absorbance values in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were 0.57±0.06, 0.53±0.04, 0.45±0.05, respectively, which were significantly lower than 0.69±0.06 in negative control group (P<0.01). After 72 hours of culture, compared with those in negative control group, the cells in the three groups treated with sodium ferulate showed varying degrees of nuclear pyknosis, fracture, or lysis, and chromatin loss. In the cytoplasm, mitochondria were swollen, the rough endoplasmic reticulum was expanded, and local vacuolation gradually appeared. After 72 hours of culture, compared with that in negative control group, the apoptosis indexes of cells were increased significantly in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group (P<0.05 or P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expressions of Bcl-2 of cells in 0.300 mg/mL sodium ferulate group was significantly decreased (P<0.01), the protein expressions of Bax of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.05), and the protein expression of caspase-3 of cells in 0.300 mg/mL sodium ferulate group was significantly increased (P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expression levels of TGF-β1, phosphorylated Smad2/3, and phosphorylated Smad4 of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly decreased (P<0.05 or P<0.01), and the protein expression levels of phosphorylated Smad7 of cells in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.01). Conclusions: Sodium ferulate can inhibit the proliferation of HSFbs of human skin and promote the apoptosis of HSFbs of human skin by blocking the expression of key proteins on the TGF-β/Smad signaling pathway and synergistically activating the mitochon- drial apoptosis pathway.

MicroRNA-98 inhibits the cell proliferation of human hypertrophic scar fibroblasts via targeting Col1A1

BACKGROUND: Hypertrophic scarring (HS) is a severe disease, and results from unusual wound healing. Col1A1 could promote the hypertrophic scar formation, and the expression of Col1A1 in HS tissue was markedly higher than that in the normal. In present study, we aimed to identify miRNAs as post-transcriptional regulators of Col1A1 in HS. METHODS: MicroRNA-98 was selected as the key miRNA comprised in HS. The mRNA levels of miR-98 in HS tissues and the matched normal skin tissues were determined by qRT-PCR. MTT and flow cytometry were used to determine the influence of miR-98 on cell proliferation and apoptosis of HSFBs, respectively. Col1A1 was found to be the target gene of miR-98 using luciferase reporter assay. Luciferase assay was performed to determine the relative luciferase activity in mimic NC, miR-98 mimic, inhibitor NC and miR-98 inhibitor with Col1A13'-UTR wt or Col1A13'-UTR mt reporter plasmids. The protein expression of Col1A1 in HSFBs after transfection with mimic NC, miR-98 mimic, inhibitor NC and miR-98 inhibitor were determined by western blotting. RESULTS: The mRNA level of miR-98 in HS tissues was much lower than that in the control. Transfection of HSFBs with a miR-98 mimic reduced the cell viability of HSFBs and increased the apoptosis portion of HSFBs, while inhibition of miR-98 increased cell viability and decreased apoptosis portion of HSFBs. miR-98 inhibitor increased the relative luciferase activity significantly when cotransfected with the Col1A1-UTR reporter plasmid, while the mutant reporter plasmid abolished the miR-98 inhibitor-mediated increase in luciferase activity. Western blotting revealed that overex-pression of miR-98 decreased the expression of Col1A1. CONCLUSIONS: Overexpression of miR-98 repressed the proliferation of HSFBs by targeting Col1A1.

Evidences of autologous fat grafting for the treatment of keloids and hypertrophic scars / Evidências da lipoenxertia autóloga para o tratamento de queloides e cicatrizes hipertróficas

SUMMARY Introduction Since the 1980s, the use of autologous fat grafting has been growing in plastic surgery. Recently, this procedure has come to be used as a treatment for keloids and hypertrophic scars mainly due to the lack of satisfactory results with other techniques. So far, however, it lacks more consistent scientific evidence to recommend its use. The aim of this study was to review the current state of autologous fat grafting for the treatment of keloids and hypertrophic scars, their benefits and scientific evidences in the literature. Method A review in the Pubmed database was performed using the keywords “fat grafting and scar”, “fat grafting and keloid scar” and “fat grafting and hypertrophic scar.” Inclusion criteria were articles written in English and published in the last 10 years, resulting in 15 studies. Results These articles indicate that autologous fat grafting carried out at sites with pathological scars leads to a reduction of the fibrosis and pain, an increased range of movement in areas of scar contraction, an increase in their flexibility, resulting in a better quality of scars. Conclusion So far, evidences suggest that autologous fat grafting for the treatment of keloids and hypertrophic scars is associated with a better quality of scars, leading to esthetic and functional benefits. However, this review has limitations and these findings should be treated with reservations, since they mostly came from studies with low levels of evidence.

RESUMO Introdução a partir da década de 1980, o uso da lipoenxertia autóloga tem crescido na cirurgia plástica. Recentemente, esse procedimento passou a ser utilizado como tratamento de queloides e cicatrizes hipertróficas, principalmente em decorrência da falta de resultados satisfatórios com outras técnicas. No entanto, até o momento, faltam evidências científicas mais consistentes que recomendem seu uso. O objetivo deste estudo foi realizar uma revisão do estado atual da lipoenxertia autóloga no tratamento de queloides e cicatrizes hipertróficas, os benefícios e as evidências científicas presentes na literatura. Método foi realizada uma revisão na base de dados Pubmed com os descritores “fat grafting and scar”, “fat grafting and keloid scar” e “fat grafting and hypertrofic scar”. Os critérios de inclusão foram artigos escritos em inglês e publicados nos últimos 10 anos, resultando em 15 estudos. Resultados os artigos indicam que a lipoenxertia autóloga realizada em locais com cicatrizes patológicas leva a uma diminuição da fibrose e da dor, à maior amplitude de movimentos em áreas de retração cicatricial, ao aumento de sua maleabilidade, resultando na melhor qualidade das cicatrizes. Conclusão até o momento, as evidências sugerem que a lipoenxertia autóloga para o tratamento das queloides e cicatrizes hipertróficas está associada à uma melhor qualidade das cicatrizes, levando a benefícios estéticos e funcionais. Contudo, esta revisão possui limitações e os acha dos devem ser analisados com ressalvas, já que a maioria provem de estudos com baixos níveis de evidência.

Normal skin and hypertrophic scar fibroblasts differentially regulate collagen and fibronectin expression as well as mitochondrial membrane potential in response to basic fibroblast growth factor

Basic fibroblast growth factor (bFGF) regulates skin wound healing; however, the underlying mechanism remains to be defined. In the present study, we determined the effects of bFGF on the regulation of cell growth as well as collagen and fibronectin expression in fibroblasts from normal human skin and from hypertrophic scars. We then explored the involvement of mitochondria in mediating bFGF-inducedeffects on the fibroblasts. We isolated and cultivated normal and hypertrophic scar fibroblasts from tissue biopsies of patients who underwent plastic surgery for repairing hypertrophic scars. The fibroblasts were then treated with different concentrations of bFGF (ranging from 0.1 to 1000 ng/mL). The growth of hypertrophic scar fibroblasts became slower with selective inhibition of type I collagen production after exposure to bFGF. However, type III collagen expression was affected in both normal and hypertrophic scar fibroblasts. Moreover, fibronectin expression in the normal fibroblasts was up-regulated after bFGF treatment. bFGF (1000 ng/mL) also induced mitochondrial depolarization in hypertrophic scar fibroblasts (P < 0.01). The cellular ATP level decreased in hypertrophic scar fibroblasts (P < 0.05), while it increased in the normal fibroblasts following treatment with bFGF (P < 0.01). These data suggest that bFGF has differential effects and mechanisms on fibroblasts of the normal skin and hypertrophic scars, indicating that bFGF may play a role in the early phase of skin wound healing and post-burn scar formation.