Zhen Gao

Remodelling of keloid tissue into normal-looking skin

rectus abdominis muscles and sheaths were preserved. The time of anaesthesia was 10 h. Postoperatively, the flaps were monitored physically using the monitor skin island. She was discharged on the 9th postoperative day. The patient is currently in the 11th postoperative month, completely satisfied with the result and the breast tissue looks and feels very natural. No abdominal wall complications, such as seroma, bulges or hernias have been observed (Figure 2).

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

Abstract 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 × 104/cm2 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 cm2 versus 0.51 ± 0.06 cm2, p < 0.05) and at 72 h (0.65 ± 0.02 cm2 versus 0.42 ± 0.01 cm2, 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.

Differential expression of growth differentiation factor-9 in keloids

OBJECTIVE The mechanisms of keloid invasion are largely unknown. This study aims to analyze the differentially expressed genes between keloid peripheral and central areas and thus to define the molecule that might be responsible for keloid invasion. METHODS The gene chip of transforming growth factor-β (TGF-β) superfamily signaling pathway was used to analyze differentially expressed genes of the fibroblasts derived from peripheral area and central area of 3 keloids. The differential expression of growth differentiation factor-9 (GDF-9) was also confirmed by quantitative PCR and Western-blot. Moreover, GDF-9 expression levels were compared among the fibroblasts derived from 3 keloids, hypertrophic scars and normal skin with quantitative PCR and immunofluorescent staining. RESULTS GDF-9 expression level was significantly higher in the peripheral area than in the central area (p<0.05) and was significantly higher in keloid than in hypertrophic scar and normal skin (p<0.05). CONCLUSION Up-regulated GDF-9 expression in keloid peripheral area may play a role in keloid invasive behavior.

Sorafenib exerts an anti-keloid activity by antagonizing TGF-β/Smad and MAPK/ERK signaling pathways

Keloid disease is characterized by hyperproliferation of responsive fibroblasts with vigorously continuous synthesis of extracellular matrix (ECM) components. Although the process by which keloids develop is poorly understood, most theories of the etiology are referred to fibroblast dysfunction. A central event in dermal repair is the release of growth factors in response to skin injury, which leads to the dysregulation of several crucial pathways that initiate the activation of keloid fibroblasts (KFs) and promote ECM accumulation. Hence, strategies aimed at reducing the production of these cytokines and/or disrupting their intracellular signal transduction have potential clinical significance for curing keloid. As the first oral multikinase inhibitor, sorafenib blocks a number of intracellular signaling pathways which are also pivotal for keloid pathogenesis. Therefore, evaluation of the effects of sorafenib on keloid disease seems timely and pertinent. In this study, we reported the identification of sorafenib that antagonized TGF-β/Smad and MAPK/ERK signaling pathways in primary KFs. Impressively, treatment with sorafenib inhibited KF cell proliferation, migration, and invasion, and simultaneously reduced collagen production in KFs. Furthermore, we present ex vivo evidence that sorafenib induced the arrest of KF migration, the inhibition of angiogenesis, and the reduction of collagen accumulation. These preclinical observations suggest that sorafenib deserves systematic exploration as a candidate agent for the future treatment of keloids.Key messageThe intracellular TGF-β/Smad and MAPK/ERK signaling pathways is blocked by sorafenib.Sorafenib inhibits the proliferation, migration, invasion, and ECM deposition in keloid fibroblasts.Sorafenib reduces KF migration and concomitantly angiogenesis in keloid explants.Sorafenib is a promising agent for the treatment of keloids and hypertrophic scars.

New potential antiscarring approaches

Significant progress has been made in scar research in which an anti‐transforming growth factor‐β strategy has already been translated from an experimental study to a clinical trial. However, scar reduction and elimination remain an unmet medical need because of the difficulty in its treatment. The authors of this article would like to propose several new potential antiscarring approaches for scar prevention including anti‐transforming growth factor‐β, multifactor therapies, tissue regeneration, and tissue‐engineered skin. In addition, scar remodeling is also proposed as an alternative new potential approach for scar therapy. We hope that some of these potential approaches might be translated into clinical scar therapies in the near future.

Enhanced expression of membrane transporter and drug resistance in keloid fibroblasts

The mechanisms of keloid resistance to therapy and high recurrence rate remain undefined. This study explored the difference in drug resistance between keloid and normal fibroblasts. Fibroblasts derived from 9 patients with keloid and 9 skin donors were randomly combined into 3 keloid cell pools (3 cases per pool) and 3 normal cell pools (3 cases per pool) and were compared for their resistance to vincristine and mitoxantrone and related molecule expression. The results revealed stronger resistance to both vincristine and mitoxantrone with a higher survival rate in keloid cells than in normal cells (P<.05). The resistance of keloid fibroblasts could be largely abrogated by verapamil treatment. In addition, messenger RNA expression levels of multiple-drug resistance-1, ABCB5 (P-glycoprotein family member), and cytochrome P450 3A4 but not ABCG2 (ATP-binding cassette transporter) were significantly higher in passage 1 keloid fibroblasts than in passage 1 normal fibroblasts; no significant difference was found in latter passages. Immunohistochemistry staining revealed significantly more multiple-drug resistance-1-positive cells (round) in keloid tissue than in normal skin (mostly spindle shaped) (P<.05) but no significant difference in the percentage of positive cells in the 2 groups. Enhanced expression of membrane transporters and increased resistance to chemotherapy agents may contribute to the keloids resistance to therapy and the high posttherapy recurrence rate.

Creating thick linear scar by inserting a gelatin sponge into rat excisional wounds

The rat incisional wound is an important model for wound scarring research, but it is also difficult to mimic thick human incisional scarring. We hypothesized that such a thick linear scarring can be generated by inserting a gelatin sponge into a rat excisional wound. The results demonstrated that the new wound model could generate 11 times wider wound width (at day 7) and 4–5 times wider scar width (at days 14, 21, and 60), respectively, than the widths of incisional wounds (p<0.05) in adult Sprague–Dawley rats. The thick linear scar created was grossly apparent in contrast to the grossly unobvious scar of the incisional wound, and a regular linear shape could be achieved with a similar scar width along the wound. The mechanism study revealed several factors that might contribute to the enhanced scarring, including delayed wound healing, enhanced inflammation, increased expression of fibrotic factors, and abnormal wound remodeling due to the insertion of the gelatin sponge. These results indicate that the new wound model of thick linear scar might be valuable for clinically relevant study of scar manipulation. Moreover, this model may serve as a tool for studying gene‐mediated tissue regeneration during wound repair using inserted gelatin sponge as a gene carrier.

Knocking out Smad3 favors allogeneic mouse fetal skin development in adult wounds.

Fetal skin development represents a process of the interaction between skin progenitor cells and their unique extracellular matrix niche, which is also important for the mechanism study of skin progenitor cell differentiation and fetal scarless wound healing. Thus, a change in the niche environment, such as altered expression levels of growth factors or cytokines, may also change the outcome of fetal skin development. This study tested the hypothesis that deletion of mouse Smad3 creates a favorable environment for fetal skin development in adult wounds. Fetal skin of green fluorescent protein mouse (C57BL/B6) of gestational day 16.5 was respectively transplanted to the wound beds of wild‐type (WT), heterozygous (HT), and homologous (KO) Smad3 deletion mice (C57BL/B6 × 129SV). The results showed that green fluorescent protein fetal mouse skin after its transplantation developed much better into hair follicle containing skin in KO or HT wound beds than in WT wound beds with significant differences in the number of follicles per mm2 among the three groups at 1, 2, and 3 weeks posttransplantation (p < 0.05). In addition, less fibrosis was observed in KO wounds than in HT and WT wounds with significant difference in the wound bed thickness among the three groups at 3 weeks posttransplantation (p < 0.05). Interestingly, there was a delayed graft rejection in the KO group when compared with the HT and WT groups. In conclusion, deletion of Smad3 in a wound bed creates a better environment for skin progenitor cell differentiation and fetal skin development. Translation of such a concept to the creation of a wound environment that is favorable for adult stem cell differentiation and skin appendage formation may become an important strategy for the regeneration of wounded skin.

Human adipose-derived stem cells inhibit bioactivity of keloid fibroblasts

BackgroundA keloid is a fibroproliferative disorder occurring in wounds characterized by an exaggerated response to injury. To date, no effective cure has been identified. As multipotent stem cells, human adipose-derived stem cells (ADSCs) may show the possibility for curing diseases such as fibrosis. This study sought to explore the potential role of human ADSCs in curing keloids.MethodsAfter culture in conditioned medium, gene and protein expression of keloid fibroblasts was examined using real-time polymerase chain reaction (RT-PCR) and Western blotting, while analysis of the cell cycle was used to measure the proliferative properties of the cells. Furthermore, ex vivo explant cultures were used to test the effects of ADSC-conditioned medium (ADSC-CM) on CD31+ and CD34+ expression in keloid tissue.ResultsOur experimental results show that ADSC-CM was able to attenuate extracellular matrix-related gene expression as well as decrease protein expression. Cell proliferation was significantly suppressed in our study. CD31+ and CD34+ vessels in ex vivo explants were reduced by 55% and 57% in treatment groups compared with control groups.ConclusionsHuman ADSC-CM significantly inhibited keloid fibroblast-related bioactivities.

Gallic acid inhibits fibroblast growth and migration in keloids through the AKT/ERK signaling pathway

Keloids are a fibroproliferative disorder of the skin resulted from abnormal healing of injured or irritated skin and are characterized by the ability to spread beyond the original boundary of the wound. Here, we tested the effect of gallic acid (GA), a plant polyphenol with selective growth inhibitory effects in cancer, on the proliferation and invasion of keloid fibroblasts (KFs) isolated from patients undergoing surgery. GA inhibited KF proliferation, migration, and invasion in parallel with the downregulation of matrix metalloproteinase-1 and -3 and upregulation of tissue inhibitors of metalloproteinase-1. Flow cytometric analysis showed that GA inhibited cell cycle progression and induced apoptosis. The effects of GA on KFs occurred in parallel with the inhibition of AKT and ERK1/2, suggesting that GA acts by suppressing the AKT/ERK signaling pathway. In ex vivo explant cultures of keloid tissues, GA inhibited the migration of KFs to the wound area and suppressed the expression of angiogenic markers concomitant with the inhibition of collagen deposition. These results identify GA as a potential therapeutic agent for the treatment of keloids and suggest a potential mechanism underlying its protective effect.