Hypertrophic scar tissues and fibroblasts produce more transforming growth factor-beta1 mRNA and protein than normal skin and cells

Exosomes Derived from Hypertrophic Scar Fibroblasts Suppress Melanogenesis in Normal Human Epidermal Melanocytes

Post-burn hypertrophic scars often exhibit abnormal pigmentation. Exosomes play important roles in maintaining normal physiological homeostasis and in the pathological development of diseases. This study investigated the effects of the exosomes derived from hypertrophic scar fibroblasts (HTSFs) on melanocytes, which are pigment-producing cells. Normal fibroblasts (NFs) and HTSFs were isolated and cultured from normal skin and hypertrophic scar (HTS) tissue. Both the NF- and HTSF-exosomes were isolated from a cell culture medium and purified using a column-based technique. The normal human epidermal melanocytes were treated with both exosomes at a concentration of 100 μg/mL at different times. The cell proliferation, melanin content in the medium, apoptotic factors, transcription factors, melanin synthesis enzymes, signaling, signal transduction pathways, and activators of transcription factors (STAT) 1, 3, 5, and 6 were investigated. Compared with the Dulbecco's phosphate-buffered saline (DPBS)-treated controls and NF-exosomes, the HTSF-exosomes decreased the melanocyte proliferation and melanin secretion. The molecular patterns of apoptosis, proliferation, melanin synthesis, Smad and non-Smad signaling, and STATs were altered by the treatment with the HTSF-exosomes. No significant differences were observed between the DPBS-treated control and NF-exosome-treated cells. HTSF-derived exosomes may play a role in the pathological epidermal hypopigmentation observed in patients with HTS.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

IL-10 dependent modulatory effect of regulatory B10 cells on local scar formation following Roux-en-Y choledochojejunostomy in a novel rat model

Choledochojejunostomy has been common surgical treatment of biliary tract disease. Scar formation at anastomotic often results in postoperative complications associated with bleak post-operative recovery, in which local inflammation may be a potential target to modulate local scar formation. This study investigated the effect of regulatory B10 cells on local scar formation through interleukin-10 signal pathway following Roux-en-Y choledochojejunostomy (RCJS) in a novel rat model. Sprague-Dawley (SD) rats with RCJS were randomly divided into blank group, experimental group, IL-10 blocking group, control group, and received different interventions and duration. Injected through dorsal vein of penis, rats in different groups were treated respectively according to scheme. These interventions were performed during surgery, on 1st day, and 2nd day after surgery. Related indexes, including blood examination, specimen tissue of anastomotic detection, were recorded and compared in different interventional groups. Rats in experimental groups had more rapid recovery in liver function and inflammatory index, and higher in IL-10 level. Flow cytometry analysis showed that rats in experimental groups had highest content of B10 cells and lowest content of CD4+CD25- T cells in peripheral blood. Wider anastomotic by macroscopical observation, and slighter proliferation of collagen fiber and smooth muscle fiber, lower α-SMA and TGF-β1 levels by pathological staining were detected in experimental groups. Higher expression of the IL-10 gene and lower expression of TGF-β1 at anastomotic were detected in experimental groups. B10 cells may relieve local inflammation of anastomotic following RCJS in rats through IL-10-dependent modulatory effect, and improve local scar formation.

A systematic investigation of the effects of TGF-β3 and mechanical stimulation on tenogenic differentiation of mesenchymal stromal cells in a poly(ethylene glycol)/gelatin-based hydrogel

Background

High post-surgical failure rates following tendon injury generate high medical costs and poor patient recovery. Cell-based tendon tissue engineering has the potential to produce fully functional replacement tissue and provide new strategies to restore tendon function and healing. In this endeavour, the application of mesenchymal stromal cells (MSCs) encapsulated in biomaterial scaffolds has shown great promise. However, a consensus on optimal promotion of tenogenic differentiation of MSCs has yet to be reached, although growth factors and mechanical cues are generally acknowledged as important factors.

Methods

In this study, we prepared a hydrogel cell culture system consisting of methacrylated poly(d,l-lactic acid-ethylene glycol-d,l-lactic acid) (P(LA-EG-LA)) and gelatin methacrylate (GelMA) to encapsulate human bone marrow-derived MSCs (hBMSCs). We further systematically investigated the influence of static and intermittent cyclic uniaxial strain mechanical stimulation, in combination with transforming growth factor-β3 (TGF-β3) supplementation, on tenogenic differentiation of hBMSCs.

Results

Increased TGF-β3 concentration upregulated the tenogenic genes Scleraxis (SCX) and collagen type I (COL1A1) but showed no effects on tenascin-c (TNC) and collagen type III (COL3A1) expression. Mechanical stimulation had no observable effect on gene expression, but intermittent cyclic uniaxial strain stimulation improved matrix deposition. Together, these data provide new insights into how TGF-β3 and mechanical stimulation regulate MSC tenogenesis, with TGF-β3 promoting the expression of key tenogenic genes whilst mechanical stimulation aided matrix deposition in the engineered tissue. Furthermore, intermittent cyclic uniaxial strain at 3% elongation and 0.33 ​Hz for 1 ​h/day showed improved matrix effects compared to static strain.

Conclusion

Together, the most promising result for tenogenic differentiation of hBMSCs was identified as treatment with 5 ​ng/ml TGF-β3 under intermittent cyclic uniaxial strain (3% strain; 0.33 ​Hz; 1 ​h/day). This knowledge is of importance for the development of an improved protocol for tenogenic differentiation of MSCs and thereby for tendon tissue engineering.

The translational potential of this article

Tissue-engineered strategies for tendon repair require a consensus on the differentiation of mesenchymal stromal cells to tenocytes, which is currently lacking. This article provides a systematic investigation of two main tenogenic differentiation conditions to further development of a tenogenic differentiation protocol.

A multimodal, comprehensive characterization of a cutaneous wound model in healthy volunteers

Development of pharmacological interventions for wound treatment is challenging due to both poorly understood wound healing mechanisms and heterogeneous patient populations. A standardized and well-characterized wound healing model in healthy volunteers is needed to aid in-depth pharmacodynamic and efficacy assessments of novel compounds. The current study aims to objectively and comprehensively characterize skin punch biopsy-induced wounds in healthy volunteers with an integrated, multimodal test battery. Eighteen (18) healthy male and female volunteers received three biopsies on the lower back, which were left to heal without intervention. The wound healing process was characterized using a battery of multimodal, non-invasive methods as well as histology and qPCR analysis in re-excised skin punch biopsies. Biophysical and clinical imaging read-outs returned to baseline values in 28 days. Optical coherence tomography detected cutaneous differences throughout the wound healing progression. qPCR analysis showed involvement of proteins, quantified as mRNA fold increase, in one or more healing phases. All modalities used in the study were able to detect differences over time. Using multidimensional data visualization, we were able to create a distinction between wound healing phases. Clinical and histopathological scoring were concordant with non-invasive imaging read-outs. This well-characterized wound healing model in healthy volunteers will be a valuable tool for the standardized testing of novel wound healing treatments.

Ursolic acid inhibits human dermal fibroblasts hyperproliferation, migration, and collagen deposition induced by TGF-β via regulating the Smad2/3 pathway

Hypertrophic scar (HS) is a skin condition characterized by excessive fibrosis with disordered collagens from skin fibroblasts, which causes abnormal esthetic and even functional symptoms, thereby affecting millions of people. Ursolic acid (UA) is widely used in skincare and exerts anti-fibrotic effects. The present study aimed to delve into the impact of UA on HS and the mechanism. Fibroblasts (FBs) were incubated with TGF-β to investigate physiological characteristics compared with FBs isolated from normal skin (NSFBs) and hyperplastic scars (HSFBs). TGF-β-incubated FBs were subjected to treatment with UA (0-20 μM). The expressions of Vimentin, α-SMA, Collagen I, and Collagen III were examined using immunofluorescence, RT-qPCR, and western blot. Cell viability, proliferation, apoptosis, migration, and contractility were examined by CCK-8, EdU, Annexin V-FITC/PI, Transwell, and collagen gel contraction assays, respectively. The activation of Smad2/3 signaling was also determined by western blot. The binding sites for UA of TGF-βR1 (ALK5) were predicted by the Autodock tool. Compared with NSFBs, the cell proliferation, migration, and contractility of both HSFBs and TGF-β-incubated FBs were all significantly up-regulated. UA markedly impaired the TGF-β-induced increase in cell proliferation, migration, and contractility, α-SMA, collagen I, and Collagen III expression of FBs. UA significantly inhibited the phosphorylation levels of Smad2/3 in TGF-β-incubated FBs with no influence on TGF-βR1 and TGF-βR2 expressions, which might be because of the binding of UA to the catalytic domain of ALK5 protein. UA attenuated TGF-β1-induced hyperproliferation, migration, and collagen deposition in FBs via regulating the Smad2/3 pathway.

The Complexity of the Post-Burn Immune Response: An Overview of the Associated Local and Systemic Complications

Burn injury induces a complex inflammatory response, both locally and systemically, and is not yet completely unravelled and understood. In order to enable the development of accurate treatment options, it is of paramount importance to fully understand post-burn immunology. Research in the last decades describes insights into the prolonged and excessive inflammatory response that could exist after both severe and milder burn trauma and that this response differs from that of none-burn acute trauma. Persistent activity of complement, acute phase proteins and pro- and anti-inflammatory mediators, changes in lymphocyte activity, activation of the stress response and infiltration of immune cells have all been related to post-burn local and systemic pathology. This "narrative" review explores the current state of knowledge, focusing on both the local and systemic immunology post-burn, and further questions how it is linked to the clinical outcome. Moreover, it illustrates the complexity of post-burn immunology and the existing gaps in knowledge on underlying mechanisms of burn pathology.

Cellular and Molecular Events of Wound Healing and the Potential of Silver Based Nanoformulations as Wound Healing Agents

Chronic wounds are a silent epidemic threatening the lives of many people worldwide. They are associated with social, health care and economic burdens and can lead to death if left untreated. The treatment of chronic wounds is very challenging as it may not be fully effective and may be associated with various adverse effects. New wound healing agents that are potentially more effective are being discovered continuously to combat these chronic wounds. These agents include silver nanoformulations which can contain nanoparticles or nanocomposites. To be effective, the discovered agents need to have good wound healing properties which will enhance their effectiveness in the different stages of wound healing. This review will focus on the process of wound healing and describe the properties of silver nanoformulations that contribute to wound healing.

Innate Immune System Response to Burn Damage-Focus on Cytokine Alteration

In the literature, burns are understood as traumatic events accompanied by increased morbidity and mortality among affected patients. Their characteristic feature is the formation of swelling and redness at the site of the burn, which indicates the development of inflammation. This reaction is not only important in the healing process of wounds but is also responsible for stimulating the patient’s innate immune system. As a result of the loss of the protective ability of the epidermis, microbes which include bacteria, fungi, and viruses have easier access to the system, which can result in infections. However, the patient is still able to overcome the infections that occur through a cascade of cytokines and growth factors stimulated by inflammation. Long-term inflammation also has negative consequences for the body, which may result in multi-organ failure or lead to fibrosis and scarring of the skin. The innate immune response to burns is not only immediate, but also severe and prolonged, and some people with burn shock may also experience immunosuppression accompanied by an increased susceptibility to fatal infections. This immunosuppression includes apoptosis-induced lymphopenia, decreased interleukin 2 (IL-2) secretion, neutrophil storm, impaired phagocytosis, and decreased monocyte human leukocyte antigen-DR. This is why it is important to understand how the immune system works in people with burns and during infections of wounds by microorganisms. The aim of this study was to characterize the molecular pathways of cell signaling of the immune system of people affected by burns, taking into account the role of microbial infections.

OUP accepted manuscript

The tendon enthesis plays a critical role in facilitating movement and reducing stress within joints. Partial enthesis injuries heal in a mechanically inferior manner and never achieve healthy tissue function. The cells responsible for tendon-to-bone healing remain incompletely characterized and their origin is unknown. Here, we evaluated the putative role of mouse skeletal stem cells (mSSCs) in the enthesis after partial-injury. We found that mSSCs were present at elevated levels within the enthesis following injury and that these cells downregulated TGFβ signaling pathway elements at both the RNA and protein levels. Exogenous application of TGFβ post-injury led to a reduced mSSC response and impaired healing, whereas treatment with a TGFβ inhibitor (SB43154) resulted in a more robust mSSC response. Collectively, these data suggest that mSSCs may augment tendon-to-bone healing by dampening the effects of TGFβ signaling within the mSSC niche.

A critical review on the potential role of adipose-derived stem cells for future treatment of hypertrophic scars

INTRODUCTION

Adipose-derived stem cells (ASCs) have recently gained researchers' interest as a solution to various diseases and conditions, including hypertrophic scar. This literature review aims to elucidate ASCs as a potential solution to alleviate hypertrophic scar in human subjects.

METHODS

Literature search was done in databases which includes PubMed, MEDLINE, and ProQuest using terms 'adipose derived stem cells', 'adipose cells', 'fat graft', 'fat grafting', 'autologous fat graft', 'fat injection', 'lipofilling', 'scar management', 'scar treatment', 'burn scar', and 'wound management'. The included articles which were published during year 2000-November 2020 must describe the use of ASCs or fat grafting or lipofilling as an attempt to alleviate hypertrophic scar.

REMARKS

Clinically, ASCs improve hypertrophic scars in terms of scar color, elasticity, texture, thickness, and size. Histologically, ASCs promotes healthy tissue regeneration, reduction in fibroblasts, and reorganisation of collagen, resembling those of normal skin. In terms of molecular aspects, ASCs alleviates hypertrophic scars through direct differentiation and paracrine mechanisms.

CONCLUSION

Adipose-derived stem cells, emerge to be a potential solution for alleviating hypertrophic scar, as demonstrated in various studies. However, there has been no studies conducted in human subjects to investigate the effect of ASCs on hypertrophic scar.

Hypertrophic Scarring: Current Knowledge of Predisposing Factors, Cellular and Molecular Mechanisms

Hypertrophic scarring (HSc) is an age-old problem that still affects millions of people physically, psychologically, and economically. Despite advances in surgical techniques and wound care, prevention and treatment of HSc remains a challenge. Elucidation of factors involved in the development of this common fibroproliferative disorder is crucial for further progress in preventive and/or therapeutic measures. Our knowledge about pathophysiology of HSc at the cellular and molecular level has grown considerably in recent decades. In this article, current knowledge of predisposing factors and the cellular and molecular mechanisms of HSc has been reviewed.

Transplanted Antler Stem Cells Stimulated Regenerative Healing of Radiation-induced Cutaneous Wounds in Rats

Radiation-induced cutaneous injury is the main side effect of radiotherapy. The injury is difficult to cure and the pathogenesis is complex. Mesenchymal stem cells (MSCs) serve as a promising candidate for cell-based therapy for the treatment of cutaneous wounds. The aim of the present study was to investigate whether antler stem cells (AnSCs) have better therapeutic effects on radiation-induced cutaneous injury than currently available ones. In this study, a rat model of cutaneous wound injury from Sr-90 radiation was used. AnSCs (1 × 10⁶/500 μl) were injected through the tail vein on the first day of irradiation. Our results showed that compared to the control group, AnSC-treated rats exhibited a delayed onset (14 days versus 7 days), shorter recovery time (51 days versus 84 days), faster healing rate (100% versus 70% on day 71), and higher healing quality with more cutaneous appendages regenerated (21:10:7/per given area compared to those of rat and human MSCs, respectively). More importantly, AnSCs promoted much higher quality of healing compared to other types of stem cells, with negligible scar formation. AnSC lineage tracing results showed that the injected-dye-stained AnSCs were substantially engrafted in the wound healing tissue, indicating that the therapeutic effects of AnSCs on wound healing at least partially through direct participation in the wound healing. Expression profiling of the wound-healing-related genes in the healing tissue of AnSC group more resembled a fetal wound healing. Revealing the mechanism underlying this higher quality of wound healing by using AnSC treatment would help to devise more effective cell-based therapeutics for radiation-induced wound healing in clinics.

Taurine ameliorates thioacetamide induced liver fibrosis in rats via modulation of toll like receptor 4/nuclear factor kappa B signaling pathway

Liver fibrosis is a significant health problem that can cause serious illness and death. Unfortunately, a standard treatment for liver fibrosis has not been approved yet due to its complicated pathogenesis. The current study aimed at assessing the anti-fibrotic effect of taurine against thioacetamide induced liver fibrosis in rats through the modulation of toll like receptor 4/nuclear factor kappa B signaling pathway. Both concomitant and late taurine treatment (100 mg/kg, IP, daily) significantly reduced the rise in serum ALT and AST activities and significantly reversed the decrease in serum albumin and total protein. These results were confirmed by histopathological examinations and immunehistochemical inspection of α-SMA, caspase-3 and NF-κB. The antioxidant potential of taurine was verified by a marked increase of GSH content and a reduction of MDA level in liver tissue. The anti-fibrotic effects of taurine were evaluated by investigating the expression of TLR4, NF-κB. The protein levels of IL-6, LPS, MyD88, MD2, CD14, TGF-β1 and TNF-α were determined. Docking studies were carried out to understand how taurine interacts inside TLR4-MD2 complex and it showed good binding with the hydrophobic binding site of MD2. We concluded that the anti-fibrotic effect of taurine was attributable to the modulation of the TLR4/NF-κB signaling.

Skin Color May Predict Intra-Abdominal Adhesions During Repeated Caesarean Section Deliveries

OBJECTIVE

Caesarean rates have increased rapidly for various reasons recently. One of the important reasons among these is medicolegal problems. Our aim with this study was to preoperatively predict abdominal adhesion density by combining the scar tissue morphology formed in the post-caesarean Pfannenstiel incision line and the skin color scoring of the patients.

MATERIAL AND METHODS

Patients who had undergone one caesarean section previously, completed their terms (37-39 weeks) and were under 35 years old were included in the study. Skin color scoring of the patients was performed using the Fitzpatrick skin color scale. Intra-abdominal adhesion scoring of the participant patients was performed using Nair's adhesion scoring system.

RESULTS

The change in abdominal adhesion scores was evaluated based on the Fitzpatrick color scale. Adhesion scores per the Nair intra-abdominal adhesion scoring system were found to be 0.04±0.209 in the FP1 group, 0.35±0.662 in the FP2 group, 1.58±0.923 in the FP3 group, and 2.33±0.577 in the FP4 group (p<0.05). These results showed a significant increase in adhesion density with increasing skin color darkness. Based on these results, it was observed that the abdominal adhesion scores and the frequency of depressed skin scar were significantly increased with increasing Fitzpatrick scores (p<0.05).

CONCLUSION

The aim of this study was to increase the prediction rates by adding the skin color scoring to the scar tissue characteristics, which have been used in previous studies. The results of this study indicate that the combination of these two parameters may be more effective in predicting intra-abdominal adhesions. Nevertheless, there is a need for studies with a much higher number of patients and multiple parameters to be able to predict intra-abdominal adhesion density preoperatively with greater accuracy.

MICAL2 regulates myofibroblasts differentiation in epidural fibrosis via SRF/MRTF-A signaling pathway

AIM

To determine the role of MICAL2 in myofibroblasts differentiation and epidural fibrosis.

BACKGROUND

Epidural fibrosis (EF) may develop following laminectomy and aberrant myofibroblasts differentiation and excessive extracellular matrix (ECM) accumulation play key roles in the formation of EF. Dense epidural fibrosis results to the poor surgical outcomes and failed back surgery syndrome (FBSS), and there is no effective treatment available. Molecule interacting with Casl2 (MICAL2) has been demonstrated to participate in multiple cellular processes by regulating actin cytoskeleton dynamics. However, its role in epidural fibrosis remains totally unverified.

MATERIALS AND METHODS

The potential functions and mechanisms of MICAL2 were explored using western blotting, immunofluorescence and lentivirus infection.

KEY FINDINGS

In our study, we determined that the MICAL2 expression was elevated in epidural fibrotic tissues and TGF-β1-stimulated fibroblasts. Moreover, knockdown of MICAL2 using MICAL2-specific short hairpin RNA attenuated TGF-β1-induced myofibroblasts differentiation and epidural fibrosis both in vitro and vivo, as indicated by decreased scar formation, reduced collagen production and down-regulated expression of α-SMA, collagen-1 and fibronectin. We also demonstrated that MICAL2 knockdown affected the migratory capability of fibroblasts in vitro. By further mechanistic research, we revealed that the MRTF-A nuclear translocation was inhibited in response to the knockdown of MICAL2 in fibroblasts and MICAL2 served as a pro-fibrotic factor in an SRF/MRTF-A-dependent manner.

SIGNIFICANCE

In conclusion, our results indicated that MICAL2 mediated myofibroblasts differentiation and promoted epidural fibrogenesis via SRF/MRTF-A signaling pathway, suggesting manipulation of MICAL2 activity as a novel alternative strategy for the prevention of epidural fibrosis.

New Gene Markers Involved in Molecular Processes of Tissue Repair, Response to Wounding and Regeneration Are Differently Expressed in Fibroblasts from Porcine Oral Mucosa during Long-Term Primary Culture

Simple Summary

Wound healing and vascularization mechanisms are key steps in the complex morphological process of tissue reconstruction. Additionally, these processes in the oral cavity are more rapid than in the skin and result in less scar formation. Epithelial cells and fibroblasts play an important role in the process of wound healing. In our study, we focused on fibroblasts and monitored changes in gene expression during their in vitro culture. Based on the analysis, we distinguished three groups of processes that play important roles in tissue regeneration: response to wounding, wound healing and vascularization. We identified genes that were involved in all three processes. These genes could be selected as tissue specific repair markers for oral fibroblasts.

Abstract

The mechanisms of wound healing and vascularization are crucial steps of the complex morphological process of tissue reconstruction. In addition to epithelial cells, fibroblasts play an important role in this process. They are characterized by dynamic proliferation and they form the stroma for epithelial cells. In this study, we have used primary cultures of oral fibroblasts, obtained from porcine buccal mucosa. Cells were maintained long-term in in vitro conditions, in order to investigate the expression profile of the molecular markers involved in wound healing and vascularization. Based on the Affymetrix assays, we have observed three ontological groups of markers as wound healing group, response to wounding group and vascularization group, represented by different genes characterized by their expression profile during long-term primary in vitro culture (IVC) of porcine oral fibroblasts. Following the analysis of gene expression in three previously identified groups of genes, we have identified that transforming growth factor beta 1 (TGFB1), ITGB3, PDPN, and ETS1 are involved in all three processes, suggesting that these genes could be recognized as markers of repair specific for oral fibroblasts within the porcine mucosal tissue.

Generation of niche tuned antifibrotic fibroblasts and non-viral mediated endothelial commitment using adipose stem cells for dermal graft development

Cell-based skin substitute generation has seen considerable development. Combining synthetic scaffolds with biomimetic fibrin does direct both exogenous and endogenous stem cell differentiation, addressing needs for reliable tissue engineering. However, lack of immediate vasculature within implantable grafts remains critical for its sustenance and integration. Multipotency, high proliferation potential, ability to release multiple growth factors (GFs), and autologous availability highlight the use of human adipose derived mesenchymal stem cells (hADMSCs) in tissue-engineered dermal grafts (TEDG) construction. However, hADMSCs' insufficiency to independently establish angiogenesis within tissue constructs demands improvement of stem cell application for dermal graft survival. Approaches to harness microenvironmentally sensitive paracrine interactions could improve the angiogenic efficiency of hADMSCs within TEDG. This study conceptualized a fibrin-based niche, to direct hADMSCs toward a nonfibrotic fibroblast commitment and incorporation of bioengineered hADMSCs, specifically releasing potent angiogenic factors within TEDG. Coexistence of tuned fibroblast and endothelial lineage committed cells contributed to well-regulated extracellular matrix formation and prevascularization. Adequate cell proliferation; sustained transient release of angiogenic GFs till 20 days; directed dermal, endothelial, fibroblast, and vascular smooth muscle cell differentiation; and favored elastin and collagen deposition were achieved in vitro. In conclusion, specific niche composition and employment of bioengineered hADMSCs favor implantable TEDG construction.

Pirfenidone inhibits epithelial-mesenchymal transition in keloid keratinocytes

Background

Keloids are benign fibroproliferative skin lesions that are difficult to treat and become a lifetime predicament for patients. Several treatment modalities have been put forth, but as yet no satisfactory approach to the prevention or treatment of keloids has been identified. The process of epithelial-to-mesenchymal transition (EMT) has been implicated in keloid scarring, as keloid keratinocytes display an EMT-like phenotype. This study investigated the potential of pirfenidone, an antifibrotic agent, to counteract EMT-like alterations in keloid keratinocytes, including gene expression, cell migratory and proliferative functions.

Methods

Normal and keloid keratinocytes were isolated from discarded normal skin tissues and from resected keloid tissues, respectively. Cells were quiesced for 24 h without epidermal growth factor DS-Qi1MCDigital and were exposed to transforming growth factor-beta1 (TGF-β1; 10 ng/mL), with or without pirfenidone (400 μg/mL), for an additional 24 h. The effects of pirfenidone on cytotoxicity, cell migration, cell proliferation, and on expression of genes and proteins involved in EMT were assayed. Statistical significance was determined by two-way ANOVA using Sigma Plot.

Results

We found that pirfenidone did not elicit any cytotoxic effect at concentrations up to 1000 μg/mL. A statistically significant dose-dependent decrease in basal cell proliferation rate was noted in both normal and keloid keratinocytes when exposed to pirfenidone at concentrations ranging from 200 to 1000 μg/mL. Pirfenidone significantly decreased basal cell migration in both normal and keloid keratinocytes, but a significant decrease in TGF-β1-induced cell migration was seen only in keloid keratinocytes. Significant inhibition of the expression of TGF-β1-induced core EMT genes, namely hyaluronan synthase 2, vimentin, cadherin-11, and wingless-type MMTV integration site family, member 5A along with fibronectin-1, was observed in both normal and keloid keratinocytes treated with pirfenidone. In addition, the protein levels of vimentin and fibronectin were significantly reduced by pirfenidone (400 μg/mL) in both normal and keloid keratinocytes.

Conclusions

For the first time, this study shows the efficacy of pirfenidone in inhibiting the EMT-like phenotype in keratinocytes derived from keloids, suggesting that pirfenidone may counteract a critical contributor of keloid progression and recurrence.

Optimal Support of Wound Healing: New Insights

BACKGROUND

The ultimate goal of wound healing following minor injury is to form a tissue regenerate that has functionality and visual appearance as close to the original skin as possible. The body's physiological response to any wound is traditionally characterised by three distinct steps: inflammation, proliferation and remodelling.

SUMMARY

New insights suggest that the three phases overlap (and even occur in parallel) in both time and space in the wound, necessitating a clinical approach that targets each stage simultaneously to ensure rapid repair and wound closure without further complications. Ingredients that exhibit activity across each of the three phases, such as dexpanthenol, are of value in the context of minor wound care and scar management. Key Messages: In addition to treatment and ingredient selection, it is also important to consider broader clinical best practices and self-care options that can be used to optimise the management of minor wounds. An individualised approach that can account for a patient's unique requirements and preferences is critical in achieving effective wound recovery.

Co-transfection of hepatocyte growth factor and truncated TGF-β type II receptor inhibit scar formation

Wound scarring remains a major challenge for plastic surgeons. Transforming growth factor (TGF)-β plays a key role in the process of scar formation. Previous studies have demonstrated that truncated TGF-β type II receptor (t-TGF-βRII) is unable to continue signal transduction but is still capable of binding to TGF-β, thereby blocking the TGF-β signaling pathway. Hepatocyte growth factor (HGF) is a multifunctional growth factor that promotes tissue regeneration and wound healing. Theoretically, the combination of HGF and t-TGF-βRII would be expected to exert a synergistic effect on promoting wound healing and reducing collagen formation. In the present study, lentivirus-mediated transfection of the two genes (t-TGF-βRII/HGF) into fibroblasts in vitro and in a rat model in vivo was used. The results demonstrated that the expression of t-TGF-βRII and HGF in NIH-3T3 cells was successfully induced. The expression of both molecules significantly reduced collagen I and III expression, and also inhibited fibroblast proliferation. Furthermore, histological examination and scar quantification revealed less scarring in the experimental wound in a rat model. Moreover, on macroscopic inspection, the experimental wound exhibited less visible scarring compared with the control. Therefore, the present study demonstrated that the combination gene therapy of t-TGF-βRII and HGF promoted wound healing, with less scarring and more epithelial tissue formation, not only by suppressing the overgrowth of collagen due to its antifibrotic effect, but also by promoting tissue regeneration.

Biological approaches for hypertrophic scars

Scar formation is usually the pathological consequence of skin trauma. And hypertrophic scars (HSs) frequently occur in people after being injured deeply. HSs are unusually considered as the result of tissue contraction and excessive extracellular matrix component deposition. Myofibroblasts, as the effector cells, mainly differentiated from fibroblasts, play the crucial role in the pathophysiology of HSs. A number of growth factors, inflammatory cytokines involved in the process of HS occurrence. Currently, with in-depth exploration and clinical research of HSs, various creative and effective treatments budded. In here, we summarize the progress in the molecular mechanism of HSs, and review the available biotherapeutic methods for their pathophysiological characteristics. Additionally, we further prospected that the comprehensive therapy may be more suitable for HS treatment.

Experimental models for cutaneous hypertrophic scar research

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

Effect of Keratinocytes on Myofibroblasts in Hypertrophic Scars

Myofibroblasts play a central role in matrix formation and wound contraction during wound healing and undergo apoptosis at the end of the healing. Hypertrophic scarring is a pathologic condition in which myofibroblasts persist in the tissue. It has been hypothesized that abnormalities in epidermal-dermal crosstalk underlie this pathology. Therefore, in this study, we investigated whether myofibroblasts are affected by keratinocytes. Transforming growth factor beta-induced myofibroblasts (Imyo) and myofibroblasts from hypertrophic scar tissue (Hmyo) were characterized using microarrays. Keratinocytes were co-cultured with myofibroblasts, and quantitative PCR analysis was performed. We found that numerous extracellular matrix- and smooth muscle cell-associated genes were upregulated in Imyo and Hmyo respectively, and these findings suggest that Hmyo are fully differentiated myofibroblasts and that Imyo are less differentiated than Hmyo. Decreased collagen type 1 gene expression was found in keratinocytes co-cultured with Imyo and Hmyo; further, α-smooth muscle actin expression in Imyo increased in the presence of keratinocytes. These observations indicate that keratinocytes play a role in the development of pathological fibrosis in hypertrophic scar tissue by regulating the behavior of dermal fibroblasts and myofibroblasts. We believe that this study provides the basis for understanding the pathophysiology of hypertrophic scarring and identifying new therapeutic approaches for this dysfunction.No Level Assigned This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors - www.springer.com/00266 .

Extensive CD34-to-CD90 Fibroblast Transition Defines Regions of Cutaneous Reparative, Hypertrophic, and Keloidal Scarring

BACKGROUND

CD90 fibroblasts have been described arising from and replacing the homeostatic CD34 network in scleroderma, but have not been specifically examined in other forms of cutaneous fibrosis.

OBJECTIVES

To address expression, timelines, and spatial relationships of CD90, CD34, and smooth muscle actin (SMA) expressing fibroblasts in scars and to examine for the presence of a CD34-to-CD90 transition.

METHODS

One hundred and seventeen scars (reparative/hypertrophic/keloidal) were evaluated for CD90, CD34, and SMA expression. Double-staining immunohistochemistry for CD90/CD34 was performed to identify CD90/CD34 transitioning cells, confirmed by double-color immunofluorescence. In addition, some scars were double-stained with CD90/SMA, CD90/procollagen-1, or SMA/procollagen-1 to evaluate spatial relationships and active collagen synthesis. Expression was graded as diffuse, minority, and negative.

RESULTS

Most scars demonstrate a CD90/CD34 pattern, and dual CD90/CD34 fibroblasts were observed in 91% of scars. In reparative scars, CD90 expression reverses to a CD34/CD90 state with maturation. Pathologic scars exhibit prolonged CD90 expression. Both CD90 and SMA fibroblasts collagenize scars, although CD90 fibroblasts are more prevalent.

CONCLUSIONS

CD90 fibroblasts likely arise from the resting CD34 fibroblastic network. Actively collagenizing scar fibroblasts exhibit a CD90/CD34 phenotype, which is prolonged in pathologic scars. CD90 fibroblasts are likely important players in cutaneous scarring.

The Dynamics of the Skin's Immune System

The skin is a complex organ that has devised numerous strategies, such as physical, chemical, and microbiological barriers, to protect the host from external insults. In addition, the skin contains an intricate network of immune cells resident to the tissue, crucial for host defense as well as tissue homeostasis. In the event of an insult, the skin-resident immune cells are crucial not only for prevention of infection but also for tissue reconstruction. Deregulation of immune responses often leads to impaired healing and poor tissue restoration and function. In this review, we will discuss the defensive components of the skin and focus on the function of skin-resident immune cells in homeostasis and their role in wound healing.

Role of Early Application of Pressure Garments following Burn Injury and Autografting

BACKGROUND

Pressure garment therapy, used for reduction of postburn scarring, is commonly initiated after complete healing of the wound or autograft. Although some clinicians have suggested that earlier treatment may improve outcomes, the effect of early initiation of therapy has not been studied in a controlled environment.

METHODS

Full-thickness burns were created on red Duroc pigs, burn eschar was excised, and the wound bed was grafted with split-thickness autografts. Grafts were treated with pressure garments immediately, 1 week (early), or 5 weeks (delayed) after grafting with nontreated grafts as controls. Scar morphology, biomechanics, and gene expression were measured at multiple time points up to 17 weeks after grafting.

RESULTS

Grafts that received pressure within 1 week after grafting exhibited no reduction in engraftment rates. Immediate and early application of pressure resulted in scars with decreased contraction, reduced scar thickness, and improved biomechanics compared with controls. Pressure garment therapy did not alter expression of collagen I, collagen III, or transforming growth factor β1 at the time points investigated; however, expression of matrix metalloproteinase 1 was significantly elevated in the immediate pressure garment therapy group at week 3, whereas the delayed pressure garment therapy and control groups approached baseline levels at this time point.

CONCLUSIONS

Early application of pressure garments is safe and effective for reducing scar thickness and contraction and improving biomechanics. This preclinical study suggests that garments should be applied as soon as possible after grafting to achieve greatest benefit, although clinical studies are needed to validate the findings in humans.

Are the cesarean section skin scar characteristics associated with intraabdominal adhesions located at surgical and non-surgical sites

OBJECTIVE

To investigate whether skin scar characteristics are associated with the presence and severity of abdominal or pelvic adhesions in women who have undergone previous cesarean section.

METHODS

In this prospective study, 104 women who had undergone at least one previous cesarean section and were scheduled for laparoscopic surgery due to benign gynaecologic indications were included. Preoperative skin scar characteristics as well as intraoperative adhesions were evaluated using the modified Manchester Scar Scale and the Peritoneal Adhesion Index, respectively.

RESULTS

During laparoscopic surgery, adhesions were detected in the upper region of the abdominal cavity in 30 women, in the middle region in 46 women and in the lower region in 82 women. Total abdominal scar scores were significantly increased in women with adhesions in all three adbominal regions. Multiple cesarean section scars and palpable scars were more common in women with adhesions. Significant positive correlations were found between the skin scar and adhesion scores in all abdominal regions.

CONCLUSION

The skin scar characteristics of the previous caesarean section are associated with the presence and severity of pelvic and abdominal adhesions. Skin scarring especially with palpable texture may be an indicator of adhesion formation in the entire abdominopelvic cavity.

The Cutaneous Inflammatory Response to Thermal Burn Injury in a Murine Model

Many burn interventions aim to target the inflammatory response as a means of enhancing healing or limiting hypertrophic scarring. Murine models of human burns have been developed, but the inflammatory response to injury in these models has not been well defined. The aim of this study was to profile inflammatory cell populations and gene expression relative to healing and scarring in a murine model of thermal burns. Cutaneous injuries were created on the dorsal region of C57Bl/6 mice using a heated metal rod. Animals were euthanized at selected time points over ten weeks, with the lesions evaluated using macroscopic measurements, histology, immunofluorescent histochemistry and quantitative PCR. The burn method generated a reproducible, partial-thickness injury that healed within two weeks through both contraction and re-epithelialization, in a manner similar to human burns. The injury caused an immediate increase in pro-inflammatory cytokine and chemokine expression, coinciding with an influx of neutrophils, and the disappearance of Langerhans cells and mast cells. This preceded an influx of dendritic cells and macrophages, a quarter of which displayed an inflammatory (M1) phenotype, with both populations peaking at closure. As with human burns, the residual scar increased in size, epidermal and dermal thickness, and mast cell numbers over 10 weeks, but abnormal collagen I-collagen III ratios, fibre organization and macrophage populations resolved 3–4 weeks after closure. Characterisation of the inflammatory response in this promising murine burn model will assist future studies of burn complications and aid in the preclinical testing of new anti-inflammatory and anti-scarring therapies.

Improved Dermal Regeneration Using a Combination of Dermal Substitutes and Dermal Fibroblast Optimization: A Hypothesis

In human adults, the repair of cutaneous wounds usually leads to scar formation rather than regeneration. Dermal substitutes have been used as a regenerative template for reducing scar formation and improving the extent of dermal regeneration. However, achievement of complete regeneration is still a long way off. Dermal substitutes are characterized by unusual regenerative activity, appearing to function by acting as temporary configurational guides for cell infiltration and synthesis of new stroma. Fibroblasts are important cells with many vital functions in wound-healing processes. They are heterogeneous with distinct characteristics according to their source location, such as subcutaneous tissue, superficial-layer dermis, and deep-layer dermis. Many studies have shown that superficial dermal fibroblasts possess the potential to form dermis-like tissue. Fibroblasts in deep-layer dermis and subcutaneous tissue may play a critical role in the formation of hypertrophic scars. Fibroblast phenotype affects the newly formed dermal architecture and influences the dermal regeneration effect induced by dermal substitutes. It is hypothesized that better regeneration of the dermis can be achieved using dermal substitutes along with dermal fibroblast optimization.

The effects of platelet-rich plasma on hypertrophic scars fibroblasts

We hypothesised that a feedback mechanism of the transforming growth factor (TGF)-β1 signalling pathway, triggered by high-level TGF-β1, activates platelet-rich plasma (PRP) release to reduce connective tissue growth factor (CTGF) production and expression of CTGF mRNA in hypertrophic scar dermal fibroblasts. Primary dermal fibroblasts were isolated from cultures of hypertrophic scars. Cells were cultured after addition of serum-free Dulbecco's modified Eagle's medium supplemented with 5% (wt/vol) PRP or platelet-poor plasma (PPP). At 1, 4, 6, 8, 11, and 13 days after addition of PRP or PPP, the TGF-β1 and CTGF levels in supernatants were determined using solid-phase enzyme-linked immunosorbent assays. Quantitative reverse transcription polymerase chain reactions were performed to quantify TGF-β1 and CTGF mRNA expression levels. TGF-β1 mRNA expression in the PRP groups was lower than in the PPP groups from 4 to 13 days of culture, and there was statistically significant difference (P < .01). CTGF level and mRNA expression in the PRP groups was lower than in the PPP groups, and there were statistically significant differences (P < .01). Although further experiments will focus on clarifying the second messenger of the TGF-β1 negative feedback mechanism, the in vitro data presented show that PRP can potentially reduce CTGF and CTGF gene transcription by triggering the TGF-β1 signalling negative feedback mechanism.

Effect of skin graft thickness on scar development in a porcine burn model

Animal models provide a way to investigate scar therapies in a controlled environment. It is necessary to produce uniform, reproducible scars with high anatomic and biologic similarity to human scars to better evaluate the efficacy of treatment strategies and to develop new treatments. In this study, scar development and maturation were assessed in a porcine full-thickness burn model with immediate excision and split-thickness autograft coverage. Red Duroc pigs were treated with split-thickness autografts of varying thickness: 0.026in. ("thin") or 0.058in. ("thick"). Additionally, the thin skin grafts were meshed and expanded at 1:1.5 or 1:4 to evaluate the role of skin expansion in scar formation. Overall, the burn-excise-autograft model resulted in thick, raised scars. Treatment with thick split-thickness skin grafts resulted in less contraction and reduced scarring as well as improved biomechanics. Thin skin autograft expansion at a 1:4 ratio tended to result in scars that contracted more with increased scar height compared to the 1:1.5 expansion ratio. All treatment groups showed Matrix Metalloproteinase 2 (MMP2) and Transforming Growth Factor β1 (TGF-β1) expression that increased over time and peaked 4 weeks after grafting. Burns treated with thick split-thickness grafts showed decreased expression of pro-inflammatory genes 1 week after grafting, including insulin-like growth factor 1 (IGF-1) and TGF-β1, compared to wounds treated with thin split-thickness grafts. Overall, the burn-excise-autograft model using split-thickness autograft meshed and expanded to 1:1.5 or 1:4, resulted in thick, raised scars similar in appearance and structure to human hypertrophic scars. This model can be used in future studies to study burn treatment outcomes and new therapies.

Cutaneous Scarring: Basic Science, Current Treatments, and Future Directions

Significance: Scarring of the skin from burns, surgery, and injury constitutes a major burden on the healthcare system. Patients affected by major scars, particularly children, suffer from long-term functional and psychological problems. Recent Advances: Scarring in humans is the end result of the wound healing process, which has evolved to rapidly repair injuries. Wound healing and scar formation are well described on the cellular and molecular levels, but truly effective molecular or cell-based antiscarring treatments still do not exist. Recent discoveries have clarified the role of skin stem cells and fibroblasts in the regeneration of injuries and formation of scar. Critical Issues: It will be important to show that new advances in the stem cell and fibroblast biology of scarring can be translated into therapies that prevent and reduce scarring in humans without major side effects. Future Directions: Novel therapies involving the use of purified human cells as well as agents that target specific cells and modulate the immune response to injury are currently undergoing testing. In the basic science realm, researchers continue to refine our understanding of the role that particular cell types play in the development of scar.

Growth factor delivery strategies for rotator cuff repair and regeneration

The high incidence of degenerative tears and prevalence of retears (20-95%) after surgical repair makes rotator cuff injuries a significant health problem. This high retear rate is attributed to the failure of the repaired tissue to regenerate the native tendon-to-bone insertion (enthesis). Biological augmentation of surgical repair such as autografts, allografts, and xenografts are confounded by donor site morbidity, immunogenicity, and disease transmission, respectively. In contrast, these risks may be alleviated via growth factor therapy, which can actively influence the healing environment to promote functional repair. Several challenges have to be overcome before growth factor delivery can translate into clinical practice such as the selection of optimal growth factor(s) or combination, identification of the most efficient stage and duration of delivery, and the design considerations for the delivery device. Emerging insight into the injury-repair microenvironment and our understanding of growth factor mechanisms in healing are informing the design of advanced delivery scaffolds to effectively treat rotator cuff tears. Here, we review potential growth factor candidates, design parameters and material selection for growth factor delivery, innovative and dynamic delivery scaffolds, and novel therapeutic targets from tendon and developmental biology for the structural and functional healing of rotator cuff repair.

Extracorporeal Shock Wave Therapy Alters the Expression of Fibrosis-Related Molecules in Fibroblast Derived from Human Hypertrophic Scar

Extracorporeal shock wave therapy (ESWT) considerably improves the appearance and symptoms of post-burn hypertrophic scars (HTS). However, the mechanism underlying the observed beneficial effects is not well understood. The objective of this study was to elucidate the mechanism underlying changes in cellular and molecular biology that is induced by ESWT of fibroblasts derived from scar tissue (HTSFs). We cultured primary dermal fibroblasts derived from human HTS and exposed these cells to 1000 impulses of 0.03, 0.1, and 0.3 mJ/mm². At 24 h and 72 h after treatment, real-time PCR and western blotting were used to detect mRNA and protein expression, respectively, and cell viability and mobility were assessed. While HTSF viability was not affected, migration was decreased by ESWT. Transforming growth factor beta 1 (TGF-β1) expression was reduced and alpha smooth muscle actin (α-SMA), collagen-I, fibronectin, and twist-1 were reduced significantly after ESWT. Expression of E-cadherin was increased, while that of N-cadherin was reduced. Expression of inhibitor of DNA binding 1 and 2 was increased. In conclusion, suppressed epithelial-mesenchymal transition might be responsible for the anti-scarring effect of ESWT, and has potential as a therapeutic target in the management of post-burn scars.

GHK Peptide Inhibits Bleomycin-Induced Pulmonary Fibrosis in Mice by Suppressing TGFβ1/Smad-Mediated Epithelial-to-Mesenchymal Transition

Objective: Idiopathic pulmonary fibrosis is an irreversible and progressive fibrotic lung disease that leads to declines in pulmonary function and, eventually, respiratory failure and has no effective treatment. Gly-His-Lys (GHK) is a tripeptide involved in the processes of tissue regeneration and wound healing and has significant inhibitory effects on transforming growth factor (TGF)-β1 secretion. The effect of GHK on fibrogenesis in pulmonary fibrosis and the exact underlying mechanism have not been studied previously. Thus, this study investigated the effects of GHK on bleomycin (BLM)-induced fibrosis and identified the pathway that is potentially responsible for these effects.

Methods: Intratracheal injections of 3 mg/kg BLM were administered to induce pulmonary fibrosis in C57BL/6 mice. GHK was administered intraperitoneally at doses of 2.6, 26, and 260 μg/ml/day every other day from the 4th to the 21st day after BLM instillation. Three weeks after BLM instillation, pulmonary injury and pulmonary fibrosis was evaluated by the hematoxylin-eosin (HE) and Masson’s trichrome (MT) staining. Chronic inflammation index was used for the histological assessments by two pathologists blindly to each other. Tumor necrosis factor (TNF)-α and IL-6 levels in BALF and myeloperoxidase (MPO) activity in lung extracts were measured. For the pulmonary fibrosis evaluation, the fibrosis index calculated based on MT staining, collagen deposition and active TGF-β1 expression detected by ELISA, and the expression of TGF-β1, α-smooth muscle actin (SMA), fibronectin, MMP-9, and TIMP-1 by western blotting. The epithelial mesenchymal transition index, E-cadherin, and vimentin was also detected by western blot. The statistical analysis was performed by one-way ANOVA and the comparison between different groups were performed.

Results: Treatment with GHK at all three doses reduced inflammatory cell infiltration and interstitial thickness and attenuated BLM-induced pulmonary fibrosis in mice. GHK treatment significantly improved collagen deposition, and MMP-9/TIMP-1 imbalances in lung tissue and also reduced TNF-α, IL-6 expression in bronchoalveolar lavage fluid (BALF) and MPO in lung extracts. Furthermore, GHK reversed BLM-induced increases in TGF-β1, p-Smad2, p-Smad-3 and insulin-like growth factor-1 (IGF-1) expression.

Conclusion: GHK inhibits BLM-induced fibrosis progression, the inflammatory response and EMT via the TGF-β1/Smad 2/3 and IGF-1 pathway. Thus, GHK may be a potential treatment for pulmonary fibrosis.

Mesenchymal stem cell in venous leg ulcer: An intoxicating therapy

Venous leg ulcers (VLU) are a prevalent and reoccurring type of complicated wound, turning as a considerable public healthcare issue, with critical social and economic concern. There are both medical and surgical therapies to treat venous leg ulcers; however, a cure does not yet exist. Mesenchymal stem cells (MSC) are capable and proved of accelerating wound healing in vivo and their study with human chronic wounds is currently awaited. MSCs are a promising source of adult progenitor cells for cellular therapy and have been demonstrated to differentiate into various mesenchymal cell lineages. They have a crucial and integral role in native wound healing by regulating immune response and inflammation. Improved understanding of the cellular and molecular mechanisms at work in delayed wound healing compels to the development of cellular therapy in VLU. This review focuses on the current treatment option of VLU and further emphasizing the role of MSCs in accelerating the healing process. With further understanding of the mechanism of action of these cells in wound improvement and, the involvement of cytokines can also be revealed that could be used for the therapeutic purpose for VLU healing. Clinical uses of MSCs have been started already, and induced MSCs are surely a promising tool or compelling therapy for VLU.

TGF-β1 promotes scar fibroblasts proliferation and transdifferentiation via up-regulating MicroRNA-21

TGF-β1, upregulated in keloid tissue, promotes the proliferation, collagen formation and differentiation of dermal fibroblasts. miR-21 is one of microRNAs first found in human genome. The aim of our study is to explore the mechanisms of miR-21 in TGF-β1-induced scar fibroblasts proliferation and transdifferentiation. In the present study, first we found that TGF-β1 promoted scar fibroblasts proliferation and transdifferentiation via up-regulating miR-21 expression, which could be attenuated when miR-21 was inhibited. Overexpression of miR-21 had similar effect as TGF-β1 on proliferation and transdifferentiation. Additionally, TGF-β1 increased the expressions and activities of MMP2 and MMP9 in keloid fibroblasts, which was suppressed by miR-21 inhibition. Finally, the results demonstrated that PTEN/AKT signaling pathway played important role in TGF-β1-induced transdifferentiation. In conclusion, our study suggests that TGF-β1 promotes keloid fibroblasts proliferation and transdifferentiation via up-regulation of miR-21 and PTEN/AKT signalling pathway plays important role in this process, which provides a potential theoretical basis for clinical treatment of skin scars.

Inhibitory effect of TGF-β peptide antagonist on the fibrotic phenotype of human hypertrophic scar fibroblasts

CONTEXT

TGF-β plays a central role in hypertrophic scar (HS) formation and development.

OBJECTIVE

This study investigated the role of a TGF-β antagonist peptide in inhibiting fibrotic behavior of human HS-derived fibroblasts (HSFs).

MATERIALS AND METHODS

HSFs were seeded at a density of 3.1 × 10(4)/cm(2) and were subjected to treatment of peptide antagonist (30 μM) or TGF-β receptor inhibitor LY2109761 (10 μM) or without treatment followed by the analyses of quantitative PCR, Elisa, in vitro wounding and fibroblast-populated collagen lattice (FPCL) assays.

RESULTS

qPCR and Elisa analyses showed that the peptide could, respectively, reduce the gene (at 48 h) and protein (at 72 h) expression levels of collagen I (86 ± 4.8%; 56.6 ± 7.3%), collagen III (73 ± 10.7%; 43.7 ± 7.2%), fibronectin (90 ± 8.9%; 21.1 ± 2.8%), and TGF-β1 (85 ± 9.3%; 25.0 ± 9.4%) as opposed to the non-treated group (p < 0.05), as the LY2109761 group similarly did. Cell proliferation was also significantly inhibited at day 5 (CCK-8 assay) by both peptide and LY2109761 treatments compared with the non-treated group (p < 0.05). The peptide also significantly inhibited cell migration as opposed to blank control at 24 h (43 ± 6.7% versus 60 ± 2.1%, p < 0.05) and at 48 h (63.9 ± 3.1% versus 95 ± 4.1%, p < 0.05). Similar to LY2109761, the peptide antagonist significantly reduced HS FPCL contraction compared with the non-treated group with significant differences in surface area at 48 h (0.71 ± 0.06 cm(2) versus 0.51 ± 0.06 cm(2), p < 0.05) and at 72 h (0.65 ± 0.02 cm(2) versus 0.42 ± 0.01 cm(2), p < 0.05).

CONCLUSION

The TGF-β antagonist peptide may serve as an important drug for HS prevention and reduction given the obvious benefits of good biosafety, low cost, and easy manufacture and delivery.

The Effects of Intradermal and Topical Mitomycin C on Wound Healing

OBJECTIVE: To determine the effect of intradermal and topical mitomycin C (MMC) on skin wound healing.

STUDY DESIGN/SETTING: A prospective, controlled study in a rat wound model performed in an academic medical center.

RESULTS: Intradermal and topical MMC application decreased wound integrity when compared with saline-treated animals at 1 week, 2 weeks, 1 month, and 6 months. Skin necrosis occurred in animals that received intradermal MMC. Hemotoxylin and eosin and immunohistochemical staining showed no consistent difference between treatment arms. Fibrosis and collagen deposition were reduced in MMC-treated wounds on trichrome staining.

CONCLUSIONS: MMC-treated wounds showed decreased wound strength compared with controls. Intradermal MMC can cause skin necrosis. Histologic findings did not always correspond with clinical data.

SIGNIFICANCE: The data suggest cautious use of MMC in clinical situations when wound breaking strength is critical.

The evidence for natural therapeutics as potential anti-scarring agents in burn-related scarring

Though survival rate following severe thermal injuries has improved, the incidence and treatment of scarring have not improved at the same speed. This review discusses the formation of scars and in particular the formation of hypertrophic scars. Further, though there is as yet no gold standard treatment for the prevention or treatment of scarring, a brief overview is included. A number of natural therapeutics have shown beneficial effects both in vivo and in vitro with the potential of becoming clinical therapeutics in the future. These natural therapeutics include both plant-based products such as resveratrol, quercetin and epigallocatechin gallate as examples and includes the non-plant-based therapeutic honey. The review also includes potential mechanism of action for the therapeutics, any recorded adverse events and current administration of the therapeutics used. This review discusses a number of potential 'treatments' that may reduce or even prevent scarring particularly hypertrophic scarring, which is associated with thermal injuries without compromising wound repair.

Comparison of transforming growth factor beta expression in healthy and diseased human tendon

Background

Diseased tendons are characterised by fibrotic scar tissue, which adversely affects tendon structure and function and increases the likelihood of re-injury. The mechanisms and expression profiles of fibrosis in diseased tendon is understudied compared to pulmonary and renal tissues, where transforming growth factor (TGF)β and its associated superfamily are known to be key drivers of fibrosis and modulate extracellular matrix homeostasis. We hypothesised that differential expression of TGFβ superfamily members would exist between samples of human rotator cuff tendons with established disease compared to healthy control tendons.

Methods

Healthy and diseased rotator cuff tendons were collected from patients presenting to an orthopaedic referral centre. Diseased tendinopathic (intact) and healthy rotator cuff tendons were collected via ultrasound-guided biopsy and torn tendons were collected during routine surgical debridement. Immunohistochemistry and quantitative real-time polymerase chain reaction were used to investigate the protein and gene expression profiles of TGFβ superfamily members in these healthy and diseased tendons.

Results

TGFβ superfamily members were dysregulated in diseased compared to healthy tendons. Specifically, TGFβ-1, TGFβ receptor (R)1 and TGFβ R2 proteins were reduced (p < 0.01) in diseased compared to healthy tendons. At the mRNA level, TGFβ R1 was significantly reduced in samples of diseased tendons, whereas TGFβ R2 was increased (p < 0.01). BMP-2, BMP-7 and CTGF mRNA remained unchanged with tendon disease.

Conclusions

We propose that downregulation of TGFβ pathways in established tendon disease may be a protective response to limit disease-associated fibrosis. The disruption of the TGFβ axis with disease suggests associated downstream pathways may be important for maintaining healthy tendon homeostasis. The findings from our study suggest that patients with established tendon disease would be unlikely to benefit from therapeutic TGFβ blockade, which has been investigated as a treatment strategy in several animal models. Future studies should investigate the expression profile of fibrotic mediators in earlier stages of tendon disease to improve understanding of the targetable mechanisms underpinning tendon fibrosis.