Adipose-derived mesenchymal stem cells inhibit cell proliferation and migration and suppress extracellular matrix synthesis in hypertrophic-scar and keloid fibroblasts

Astragalin inhibits fibroblast proliferation, motion, and ECM synthesis and regulates the MAPK pathway in keloid

Keloid is a fibroproliferative skin disorder characterized by fibroblast hyperproliferation and excessive extracellular matrix (ECM) deposition. Astragalin (AST) is a bioactive natural flavonoid with multiple pharmacological properties. This study aims to investigate the effect of AST on keloid formation in vitro. Primary keloid fibroblasts (KFs) and normal fibroblasts (NFs) were isolated from human keloid tissues and normal skin tissues, respectively, and treated with or without AST. MTT, colony formation, and Transwell assays were utilized to evaluate AST's effect on fibroblast proliferation, migration, and invasiveness. Western blotting was implemented for detecting protein levels of ECM components and mitogen-activated protein kinases (MAPKs). The results showed that AST treatment hindered the proliferative, migratory, and invasive capacities of KFs and NFs, and KFs were more sensitive to AST than NFs. AST restrained ECM deposition and inactivated the MAPK signaling pathway in KFs and NFs. In conclusion, AST suppresses the invasive growth of keloid fibroblasts probably by inactivating MAPK signaling.

Altered Arginine Metabolism Affects Proliferation and Radiosensitivity of Keloids

Keloid is characterised by the reprogramming of cellular metabolism, wherein keloid cells adapt their metabolic pathways to meet the demands for energy and biosynthetic precursors. Investigating the intricate relationship between cellular metabolism and the biological behaviour of keloid holds the potential to yield novel therapeutic strategies for keloid. To elucidate the molecular alterations and potential underlying regulatory mechanisms in keloids, we created comprehensive metabolic profiling at the pathway level by analysing metabolomic, transcriptomic and single-cell RNA-sequencing data from keloids and adjacent skin. Viability assay and clonogenic assay were performed to validate the function of the metabolic pathway(s) in primary keloid fibroblast cells. Integrated analysis revealed an upregulation of arginine and proline metabolism in keloids. According to single-cell RNA-seq data, elevated expression of genes related to arginine and proline metabolism, such as P4HA3, P4HA2, P4HA1, PYCR1, OAT and ASS1, was predominately highly expressed in fibroblast-2. Fibroblast-2 displayed more obvious phenotypes of mesenchymal fibroblast. Critical genes from integrated analysis including P4HA3, P4HA2, P4HA1, PYCR1 and AZIN2, and metabolites including fumaric acid and 2-oxo-5-amino-pentanoic acid showed prognostic relevance with disease-free survival of keloid. Additionally, an In vitro study showed that arginine deprivation therapy (ADT) inhibited and radiosensitised the proliferation of keloid-derived fibroblasts. In conclusion, our thorough multiomics study deepens our understanding of the link between arginine and proline metabolism and keloid proliferation and radiosensitivity. Elevated activity of arginine and proline metabolism in mesenchymal fibroblasts may be a potential therapeutic pathway for keloid.

Inhibition of Small Extracellular Vesicles by GW4869 Does not Disrupt the Paracrine Regulation of Adipose-Derived Mesenchymal Stem Cells Over Keloid Fibroblasts

BACKGROUND

Keloid, scar caused by atypical wound repair, represents a significant difficulty for specialists in plastic surgery and dermatology. Adipose-derived mesenchymal stem cells (ADSCs) can regulate fibrotic phenotypes of keloid fibroblasts (KFs) in a paracrine fashion, but whether small extracellular vesicles (SEVs) are the key functional carrier in ADSC paracrine regulation of KFs remains unknown. This study aims to explore whether the regulatory effects of conditioned medium (CM) obtained from ADSCs on KFs can be impaired by decreased SEV content in the ADSC-CM.

METHODS

Clinical specimens were utilized to extract keloid fibroblasts (KFs), normal fibroblasts (NFs), and adipose-derived stem cells (ADSCs). Fibroblasts were cultured with CM obtained from ADSCs untreated or treated with the sphingomyelinase inhibitor GW4869. The features of SEVs derived from ADSC-CM were characterized, and fibroblast proliferation, migration, apoptosis, and expression of ECM proteins were analyzed.

RESULTS

The sphingomyelinase inhibitor GW4869 successfully reduced the SEV content in ADSC-CM, and both control ADSC-CM and ADSC-CM with reduced SEV content significantly inhibited KF proliferation, migration, and α-SMA synthesis but not KF apoptosis, whereas only NF proliferation was inhibited by ADSC-CM. The reduced SEV content only affected the inhibition of KF proliferation induced by ADSC-CM.

CONCLUSION

ADSC-CM inhibits various fibrotic phenotypes of KFs, but decreasing the SEV content in ADSC-CM did not significantly alter the antifibrotic effects of ADSC-CM. Thus, SEVs may not be the key mediator of ADSCs paracrine regulation of KFs.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 .

Immediate SVF-Gel Injection Reduced Incision Scar Formation: A Prospective, Double-Blind, Randomized, Self-control Trial

BACKGROUND

Skin incision scars are cosmetically displeasing; the effects of current treatments are limited, and new methods to reduce scar formation need to be found.

OBJECTIVE

We sought to determine whether immediate postoperative injection of stromal vascular fraction gel (SVF-gel) could reduce scar formation at skin incision sites.

METHODS

A prospective, randomized, double-blind, self-controlled trial was conducted in patients who underwent breast reduction. SVF-gel was intradermally injected into the surgical incision on one randomly selected side, with the other side receiving saline as a control. At the 6-month follow-up, the incision scars were evaluated using the Vancouver scar scale (VSS) and visual analog scale (VAS). Antera 3D camera was used for objective evaluation.

RESULTS

The VSS score and VAS score were significantly different between the SVF-gel-treated side (3.80 ± 1.37, 3.37±1.25) and the control side (5.25 ± 1.18, 4.94 ± 1.28). Moreover, the SVF-gel-treated side showed statistically significant improvements in scar appearance, based on evidences from Antera 3D camera.

LIMITATIONS

This was a single-center, single-race, and single-gender study. Furthermore, the results were available only for the 6-month interim follow-up period.

CONCLUSION

Postoperative immediate SVF-gel injection in surgical incisions can reduce scar formation, and exert a preventive effect on scars.

LEVEL OF EVIDENCE I

Evidence obtained from at least one properly designed randomized controlled trial. 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 .

Stem cell-based therapy for fibrotic diseases: mechanisms and pathways

Fibrosis is a pathological process, that could result in permanent scarring and impairment of the physiological function of the affected organ; this condition which is categorized under the term organ failure could affect various organs in different situations. The involvement of the major organs, such as the lungs, liver, kidney, heart, and skin, is associated with a high rate of morbidity and mortality across the world. Fibrotic disorders encompass a broad range of complications and could be traced to various illnesses and impairments; these could range from simple skin scars with beauty issues to severe rheumatologic or inflammatory disorders such as systemic sclerosis as well as idiopathic pulmonary fibrosis. Besides, the overactivation of immune responses during any inflammatory condition causing tissue damage could contribute to the pathogenic fibrotic events accompanying the healing response; for instance, the inflammation resulting from tissue engraftment could cause the formation of fibrotic scars in the grafted tissue, even in cases where the immune system deals with hard to clear infections, fibrotic scars could follow and cause severe adverse effects. A good example of such a complication is post-Covid19 lung fibrosis which could impair the life of the affected individuals with extensive lung involvement. However, effective therapies that halt or slow down the progression of fibrosis are missing in the current clinical settings. Considering the immunomodulatory and regenerative potential of distinct stem cell types, their application as an anti-fibrotic agent, capable of attenuating tissue fibrosis has been investigated by many researchers. Although the majority of the studies addressing the anti-fibrotic effects of stem cells indicated their potent capabilities, the underlying mechanisms, and pathways by which these cells could impact fibrotic processes remain poorly understood. Here, we first, review the properties of various stem cell types utilized so far as anti-fibrotic treatments and discuss the challenges and limitations associated with their applications in clinical settings; then, we will summarize the general and organ-specific mechanisms and pathways contributing to tissue fibrosis; finally, we will describe the mechanisms and pathways considered to be employed by distinct stem cell types for exerting anti-fibrotic events.

Insights into the role of adipose-derived stem cells and secretome: potential biology and clinical applications in hypertrophic scarring

Scar tissue is the inevitable result of repairing human skin after it has been subjected to external destructive stimuli. It leads to localized damage to the appearance of the skin, accompanied by symptoms such as itching and pain, which reduces the quality of life of the patient and causes serious medical burdens. With the continuous development of economy and society, there is an increasing demand for beauty. People are looking forward to a safer and more effective method to eliminate pathological scarring. In recent years, adipose-derived stem cells (ADSCs) have received increasing attention from researchers. It can effectively improve pathological scarring by mediating inflammation, regulating fibroblast proliferation and activation, and vascular reconstruction. This review focuses on the pathophysiological mechanisms of hypertrophic scarring, summarizing the therapeutic effects of in vitro, in vivo, and clinical studies on the therapeutic effects of ADSCs in the field of hypertrophic scarring prevention and treatment, the latest application techniques, such as cell-free therapies utilizing ADSCs, and discussing the advantages and limitations of ADSCs. Through this review, we hope to further understand the characterization of ADSC and clarify the effectiveness of its application in hypertrophic scarring treatment, so as to provide clinical guidance.

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Human Umbilical Mesenchymal Stem Cells-Derived Microvesicles Attenuate Formation of Hypertrophic Scar through Multiple Mechanisms

Mesenchymal stem cells and the derived extracellular microvesicles are potential promising therapy for many disease conditions, including wound healing. Since current therapeutic approaches do not satisfactorily attenuate or ameliorate formation of hypertrophic scars, it is necessary to develop novel drugs to achieve better outcomes. In this study, we investigated the effects and the underlying mechanisms of human umbilical mesenchymal stem cells (HUMSCs)-derived microvesicles (HUMSCs-MVs) on hypertrophic scar formation using a rabbit ear model and a human foreskin fibroblasts (HFF) culture model. The results showed that HUMSCs-MVs reduced formation of hypertrophic scar tissues in the rabbit model based on appearance observation, and hematoxylin and eosin (H&E), Masson, and immunohistochemical stainings. HUMSCs-MVs inhibited invasion of HFF cells and decreased the levels of the α-SMA, N-WASP, and cortacin proteins. HUMSCs-MVs also inhibited cell proliferation of HFF cells. The MMP-1, MMP-3, and TIMP-3 mRNA levels were significantly increased, and the TIMP-4 mRNA level and the NF-kB p65/β-catenin protein levels were significantly decreased in HFF cells after HUMSCs-MVs treatment. The p-SMAD2/3 levels and the ratios of p-SMAD2/3/SMAD2/3 were significantly decreased in both the wound healing tissues and HFF cells after HUMSCs-MVs treatment. CD34 levels were significantly decreased in both wound healing scar tissues and HFF cells after HUMSCs-MVs treatment. The VEGF-A level was also significantly decreased in HFF cells after HUMSCs-MVs treatment. The magnitudes of changes in these markers by HUMSCs-MVs were mostly higher than those by dexamethasone. These results suggested that HUMSCs-MVs attenuated formation of hypertrophic scar during wound healing through inhibiting proliferation and invasion of fibrotic cells, inflammation and oxidative stress, Smad2/3 activation, and angiogenesis. HUMSCs-MVs is a potential promising drug to attenuate formation of hypertrophic scar during wound healing.

Safety and feasibility of autologous adipose-derived stromal vascular fraction in the treatment of keloids: a phase one randomized controlled pilot trial

INTRODUCTION

Autologous adipose-derived stromal vascular fraction (SVF) has been described to have therapeutic benefits in the treatment of keloids. However, most of the evidence on its efficacy is based on observational studies the majority of which are conducted in high-income countries and yet the highest burden of keloids is in low- and middle-income countries (LMICs).

OBJECTIVES

We set out to determine the safety and feasibility of using autologous adipose derived stromal vascular fraction in the treatment of keloids in LMICs.

METHODS

In this phase II randomized controlled pilot clinical trial conducted in the Plastic Surgery Unit of Kirruddu National Referral Hospital in Kampala Uganda, 8 patients were assigned a 1:1 ratio to either SVF or triamcinolone acetonide (TAC) arms. In the SVF arm, a median (Inter quartile range) amount of stromal cell infiltration of 2.7×106 (11×106) was administered, while the controls received 10 mg/ml TAC at a ratio of 1:1 TAC to keloid volume. Primary endpoints were adverse event development based on the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 tool and feasibility assessment based on ≥ 70% recruitment feasibility and ≥ 80% interventional feasibility rates.

RESULTS

The participants' mean age was 27.9 (±6.5) years, with a female predilection of 5 (63%). Overall, no adverse events were reported in the SVF arm, while ulceration in a single patient in the TAC arm, which was a grade II adverse event, was reported. Recruitment feasibility of 80% and interventional feasibility with 100% completion were reported.

CONCLUSION

Based on our findings, an autologous adipose-derived stromal vascular fraction is feasible and safe for the treatment of keloids in LMICs.

[Influence of autologous adipose stem cell matrix gel on wound healing and scar hyperplasia of full-thickness skin defects in rabbit ears]

Objective: To investigate the influence of autologous adipose stem cell matrix gel on wound healing and scar hyperplasia of full-thickness skin defects in rabbit ears, and to analyze the related mechanism. Methods: Experimental research methods were adopted. The complete fat pads on the back of 42 male New Zealand white rabbits aged 2 to 3 months were cut to prepare adipose stem cell matrix gel, and a full-thickness skin defect wound was established on the ventral side of each ear of each rabbit. The left ear wounds were included in adipose stem cell matrix gel group (hereinafter referred to as matrix gel group), and the right ear wounds were included in phosphate buffer solution (PBS) group, which were injected with autologous adipose stem cell matrix gel and PBS, respectively. The wound healing rate was calculated on post injury day (PID) 7, 14, and 21, and the Vancouver scar scale (VSS) scoring of scar tissue formed on the wound (hereinafter referred to as scar tissue) was performed in post wound healing month (PWHM) 1, 2, 3, and 4. Hematoxylin-eosin staining was performed to observe and measure the histopathological changes of wound on PID 7, 14, and 21 and the dermal thickness of scar tissue in PWHM 1, 2, 3, and 4. Masson staining was performed to observe the collagen distribution in wound tissue on PID 7, 14, and 21 and scar tissue in PWHM 1, 2, 3, and 4, and the collagen volume fraction (CVF) was calculated. The microvessel count (MVC) in wound tissue on PID 7, 14, and 21 and the expressions of transforming growth factor β1 (TGF-β1) and α smooth muscle actin (α-SMA) in scar tissue in PWHM 1, 2, 3, and 4 were detected by immunohistochemical method, and the correlation between the expression of α-SMA and that of TGF-β1 in scar tissue in matrix gel group was analyzed. The expressions of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) in wound tissue were detected by enzyme-linked immunosorbent assay on PID 7, 14, and 21. The number of samples at each time point in each group was 6. Data were statistically analyzed with analysis of variance for repeated measurement, analysis of variance for factorial design, paired sample t test, least significant difference test, and Pearson correlation analysis. Results: On PID 7, the wound healing rate in matrix gel group was (10.3±1.7)%, which was close to (8.5±2.1)% in PBS group (P>0.05). On PID 14 and 21, the wound healing rates in matrix gel group were (75.5±7.0)% and (98.7±0.8)%, respectively, which were significantly higher than (52.7±6.7)% and (90.5±1.7)% in PBS group (with t values of 5.79 and 10.37, respectively, P<0.05). In PWHM 1, 2, 3, and 4, the VSS score of scar tissue in matrix gel group was significantly lower than that in PBS group (with t values of -5.00, -2.86, -3.31, and -4.45, respectively, P<0.05). Compared with the previous time point within the group, the VSS score of scar tissue at each time point after wound healing in the two groups was significantly increased (P<0.05), except for PWHM 4 in matrix gel group (P>0.05). On PID 7, the granulation tissue regeneration and epithelialization degree of the wounds between the two groups were similar. On PID 14 and 21, the numbers of fibroblasts, capillaries, and epithelial cell layers in wound tissue of matrix gel group were significantly more than those in PBS group. In PWHM 1, 2, 3, and 4, the dermal thickness of scar tissue in matrix gel group was significantly thinner than that in PBS group (with t values of -4.08, -5.52, -6.18, and -6.30, respectively, P<0.05). Compared with the previous time point within the group, the dermal thickness of scar tissue in the two groups thickened significantly at each time point after wound healing (P<0.05). Compared with those in PBS group, the collagen distribution in wound tissue in matrix gel group was more regular and the CVF was significantly increased on PID 14 and 21 (with t values of 3.98 and 3.19, respectively, P<0.05), and the collagen distribution in scar tissue was also more regular in PWHM 1, 2, 3, and 4, but the CVF was significantly decreased (with t values of -7.38, -4.20, -4.10, and -4.65, respectively, P<0.05). Compared with the previous time point within the group, the CVFs in wound tissue at each time point after injury and scar tissue at each time point after wound healing in the two groups were significantly increased (P<0.05), except for PWHM 1 in matrix gel group (P>0.05). On PID 14 and 21, the MVC in wound tissue in matrix gel group was significantly higher than that in PBS group (with t values of 4.33 and 10.10, respectively, P<0.05). Compared with the previous time point within the group, the MVC of wound at each time point after injury in the two groups was increased significantly (P<0.05), except for PID 21 in PBS group (P>0.05). In PWHM 1, 2, 3, and 4, the expressions of TGF-β1 and α-SMA in scar tissue in matrix gel group were significantly lower than those in PBS group (with t values of -2.83, -5.46, -5.61, -8.63, -10.11, -5.79, -8.08, and -11.96, respectively, P<0.05). Compared with the previous time point within the group, the expressions of TGF-β1 and α-SMA in scar tissue in the two groups were increased significantly at each time point after wound healing (P<0.05), except for the α-SMA expression in matrix gel group in PWHM 4 (P>0.05). There was a significantly positive correlation between the expression of α-SMA and that of TGF-β1 in scar tissue in matrix gel group (r=0.92, P<0.05). On PID 14 and 21, the expressions of VEGF (with t values of 6.14 and 6.75, respectively, P<0.05) and EGF (with t values of 8.17 and 5.85, respectively, P<0.05) in wound tissue in matrix gel group were significantly higher than those in PBS group. Compared with the previous time point within the group, the expression of VEGF of wound at each time point after injury in the two groups was increased significantly (P<0.05), and the expression of EGF was decreased significantly (P<0.05). Conclusions: Adipose stem cell matrix gel may significantly promote the wound healing of full-thickness skin defects in rabbit ears by promoting collagen deposition and expressions of VEGF and EGF in wound tissue, and may further inhibit the scar hyperplasia after wound healing by inhibiting collagen deposition and expressions of TGF-β1 and α-SMA in scar tissue.

[Research advances on pharmacological interventions for hypertrophic scar]

Hypertrophic scar is an abnormal fibrous proliferative disease that occurs after deep cutaneous injury, which not only affects aesthetics and function but also has negative psychological effects on the patients. However, the mechanism of hypertrophic scar formation has not been fully elucidated, and its clinical treatment is complex with a high rate of recurrence and no radicle cure. Intervention based on molecular targets will likely be the future direction for the prevention and treatment of hypertrophic scar. In this article, we review the specific roles and mechanisms of drug-targeted interventions in hypertrophic scar formation, including general drugs, cytokines, immunomodulators, herbal extracts, exosomes, and nanomaterials, in the context of advances in both basic and clinical research at home and abroad.

Keloid Patient Plasma-Derived Exosomal hsa_circ_0020792 Promotes Normal Skin Fibroblasts Proliferation, Migration, and Fibrogenesis via Modulating miR-193a-5p and Activating TGF-β1/Smad2/3 Signaling

Background

Keloids are fibroproliferative disorders, which seriously affect the quality of life of patients with keloids. Additionally, circRNAs are enriched within exosomes derived from human blood samples, whereas their relationship with keloids remains largely unknown. It has been reported that hsa_circ_0020792 was abnormally upregulated in keloid tissues. However, the role of keloid patient plasma-derived exosomal hsa_circ_0020792 in the formation and development of keloids is not well understood.

Methods

Exosomes were isolated from the peripheral blood plasma of the patients with keloids (keloid patient-Exo) and healthy controls (Healthy control-Exo). The hsa_circ_0020792 and miR-193a-5p levels in keloid patient-Exo and healthy control-Exo, as well as in keloid fibroblasts and normal skin fibroblasts (NFs) were evaluated by RT-qPCR.

Results

The level of hsa_circ_0020792 was remarkably increased in keloid patient-Exo and keloid fibroblasts compared with that in Healthy control-Exo and NFs, respectively. In addition, keloid patient-Exo obviously enhanced the viability, migration, and extracellular matrix (ECM) synthesis, but reduced the apoptosis of NFs. Moreover, keloid patient-Exo notably promoted the fibrogenesis of NFs, as characterized by enhanced TGF-β signaling, increased expressions of phosphorylated Smad2/3. However, downregulation of hsa_circ_0020792 markedly reversed the promoting effects of keloid patient-Exo on cell growth, migration, and myofibroblast activation and fibrogenesis. Furthermore, downregulation of hsa_circ_0020792 significantly reduced the viability, migration, and fibrogenesis in NFs, whereas these phenomena were reversed by miR-193a-5p inhibitor.

Conclusion

Collectively, keloid patient plasma-derived exosomal hsa_circ_0020792 could promote the proliferation, migration, and fibrogenesis of NFs via modulating miR-193a-5p and activating TGF-β1/Smad2/3 signaling.

Activation of the NFκB signaling pathway in IL6+CSF3+ vascular endothelial cells promotes the formation of keloids

Background: Keloid is a disease caused by abnormal proliferation of skin fibres, the causative mechanism of which remains unclear.

Method: In this study, endothelial cells of keloids were studied using scRNAseq combined with bulk-RNAseq data from keloids. The master regulators driving keloid development were identified by transcription factor enrichment analysis. The pattern of changes in vascular endothelial cells during keloid development was explored by inferring endothelial cell differentiation trajectories. Deconvolution of bulkRNAseq by CIBERSORTX verified the pattern of keloidogenesis. Immunohistochemistry for verification of the lesion process in keloid endothelial cells.

Results: The endothelial cells of keloids consist of four main cell populations (MMP1+ Endo0, FOS + JUN + Endo1, IL6+CSF3+Endo2, CXCL12 + Endo3). Endo3 is an endothelial progenitor cell, Endo1 is an endothelial cell in the resting state, Endo2 is an endothelial cell in the activated state and Endo0 is an endothelial cell in the terminally differentiated state. Activation of the NFΚB signaling pathway is a typical feature of Endo2 and represents the early skin state of keloids.

Conclusion: We have identified patterns of vascular endothelial cell lesions during keloidogenesis and development, and have found that activation of the NFΚB signaling pathway is an essential feature of keloid formation. These findings are expected to contribute to the understanding of the pathogenesis of keloids and to the development of new targeted therapeutic agents for the lesional characteristics of vascular endothelial cells.

Potency assays for human adipose-derived stem cells as a medicinal product toward wound healing

In pre-clinical studies, human adipose-derived stem cells (hASCs) have shown great promise as a treatment modality for healing of cutaneous wounds. The advantages of hASCs are that they are relatively easy to obtain in large numbers from basic liposuctions, they maintain their characteristics after long-term in vitro culture, and they possess low immunogenicity, which enables the use of hASCs from random donors. It has been hypothesized that hASCs exert their wound healing properties by reducing inflammation, inducing angiogenesis, and promoting fibroblast and keratinocyte growth. Due to the inherent variability associated with the donor-dependent nature of ASC-based products, it appears necessary that the quality of the different products is prospectively certified using a set of most relevant potency assays. In this review, we present an overview of the available methodologies to assess the Mode and the Mechanism of Action of hASCs, specifically in the wound healing scenario. In conclusion, we propose a panel of potential potency assays to include in the future production of ASC-based medicinal products.

Treatment of Osteochondral Femoral Head Defect by Human Umbilical Cord Mesenchymal Stem Cell Sheet Transplantation: An Experimental Study in Rats

INTRODUCTION

Articular cartilage is limited in self-repair following injuries due to avascular, lymphatic, and nerve absence. Recent treatments for cartilage injuries, such as physical therapy, anti-inflammatory medication, chondrocyte implantation, and joint replacement, still have limitations. This study aimed to evaluate the treatment efficacy of human umbilical cord-derived mesenchymal stem cell sheet (UCMSCS) transplantation in rat models of the osteochondral femoral head defect.

METHODS

Models of osteochondral femoral head defect were produced in rats by drilling in order to reach the femoral bone tissue through the cartilage layer. Then, UCMSCS was implanted in the created cartilage lesion. The treatment efficacy was monitored by X-ray imaging. The cartilage regeneration was evaluated based on the hematoxylin and eosin staining, and proteoglycan accumulation was detected by staining Safranin O and Fast Green. The physiological, weight, or movement activity of rats were recorded during the treatment period.

RESULTS

UCMSCS transplantation showed positive effects on the cartilage regeneration in osteochondral femoral head defect grade 4 (according to ICRS score/grade). Particularly, after 12 weeks of implantation of UCMSCS, the defect was filled with hyaline cartilage-like cells and accumulated a large density of proteoglycan. The osteochondral defect score significantly increased in the treated rats compared to the untreated rats (11.67 ± 0.6 and 9.67 ± 0.6, respectively) (p < 0.05). The histological score also increased in treated rats compared to untreated rats (21.33 ± 1.53 vs. 18.00 ± 1.00) (p < 0.0001). The accumulation of proteoglycan was higher in treated rats (20.50 ± 2.23) than untreated rats (5.38 ± 0.36) (p < 0.05). There was no change in the physiological activities between treated and untreated rats recorded during the study.

CONCLUSION

MSCS transplantation could promote regeneration in advanced cartilage injury.

Botulinum toxin A promotes the transdifferentiation of primary keloid myofibroblasts into adipocyte-like cells

Keloid is a type of unusually raised scar. Botulinum toxin A (BTX-A) has a great application potential in keloids treatment. Here, we investigated the functional role of BTX-A in keloids. We separated keloid tissues and normal skin tissues from keloid patients and found that the expression of myofibroblast markers, α-SMA, Collagen I, and Collagen III was increased in the keloid tissues as compared with normal skin tissues. Keloid fibroblasts derived from keloid tissues were treated with TGF-β1 to induce the differentiation of fibroblasts into myofibroblasts. The keloid myofibroblasts displayed a significant up-regulation of α-SMA. BTX-A enhanced the expression of adipocyte markers, PPARγ and C/EBPα, and increased the accumulation of lipid droplets, and reduced the expression of α-SMA, Collagen I, and Collagen III in the keloid myofibroblasts. Moreover, BTX-A enhanced the expression of BMP4 and p-smad1/5/8. Noggin (BMP4 antagonist) treatment reversed BTX-A-mediated increase of PPARγ and C/EBPα expression and lipid droplets, and down-regulation of α-SMA, Collagen I, and Collagen III in primary keloid myofibroblasts. In conclusion, BTX-A promoted the transdifferentiation of primary keloid myofibroblasts into adipocyte-like cells, which may attribute to activate BMP4/Smad signalling pathway. Thus, this study provides new insights into the mechanism of BTX-A in keloid.

Evaluation of the Effects of Human Dental Pulp Stem Cells on the Biological Phenotype of Hypertrophic Keloid Fibroblasts

OBJECTIVE

Despite numerous existing treatments for keloids, the responses in the clinic have been disappointing, due to either low efficacy or side effects. Numerous studies dealing with preclinical and clinical trials have been published about effective therapies for fibrotic diseases using mesenchymal stem cells; however, no research has yet been reported to scientifically investigate the effect of human dental pulp stem cells (HDPSCs) on the treatment of keloids. The objective is to provide an experimental basis for the application of stem cells in the treatment of keloids.

METHODS

Human normal fibroblasts (HNFs) and human keloid fibroblasts (HKFs) were cultured alone and in combination with HDPSCs using a transwell cell-contact-independent cell culture system. The effects of HDPSCs on HKFs were tested using a CCK-8 assay, live/dead staining assay, quantitative polymerase chain reaction, Western blot and immunofluorescence microscopy.

RESULTS

HDPSCs did not inhibit the proliferation nor the apoptosis of HKFs and HNFs. HDPSCs did, however, inhibit their migration. Furthermore, HDPSCs significantly decreased the expression of profibrotic genes (CTGF, TGF-β1 and TGF-β2) in HKFs and KNFs (p < 0.05), except for CTGF in HNFs. Moreover, HDPSCs suppressed the extracellular matrix (ECM) synthesis in HKFs, as indicated by the decreased expression of collagen I as well as the low levels of hydroxyproline in the cell culture supernatant (p < 0.05).

CONCLUSIONS

The co-culture of HDPSCs inhibits the migration of HKFs and the expression of pro-fibrotic genes, while promoting the expression of anti-fibrotic genes. HDPSCs' co-culture also inhibits the synthesis of the extracellular matrix by HKFs, whereas it does not affect the proliferation and apoptosis of HKFs. Therefore, it can be concluded that HDPSCs can themselves be used as a tool for restraining/hindering the initiation or progression of fibrotic tissue.

Stem cells in the treatment of renal fibrosis: a review of preclinical and clinical studies of renal fibrosis pathogenesis

Renal fibrosis commonly leads to glomerulosclerosis and renal interstitial fibrosis and the main pathological basis involves tubular atrophy and the abnormal increase and excessive deposition of extracellular matrix (ECM). Renal fibrosis can progress to chronic kidney disease. Stem cells have multilineage differentiation potential under appropriate conditions and are easy to obtain. At present, there have been some studies showing that stem cells can alleviate the accumulation of ECM and renal fibrosis. However, the sources of stem cells and the types of renal fibrosis or renal fibrosis models used in these studies have differed. In this review, we summarize the pathogenesis (including signaling pathways) of renal fibrosis, and the effect of stem cell therapy on renal fibrosis as described in preclinical and clinical studies. We found that stem cells from various sources have certain effects on improving renal function and alleviating renal fibrosis. However, additional clinical studies should be conducted to confirm this conclusion in the future.

[Expression and effect of microRNA-627 in human hypertrophic scar]

Objective: To investigate the expression and effect of microRNA-627 (miR-627) in human hypertrophic scar. Methods: The experimental research method was used. From October 2019 to January 2020, hypertrophic scar tissue from 6 patients with hypertrophic scar (2 males and 4 females, aged (34±11) years) and the remaining normal skin tissue from 6 trauma patients (3 males and 3 females, aged (35±13) years) after flap transplantation were collected. The above-mentioned 12 patients were admitted to the General Hospital of Northern Theater Command and met the inclusion criteria. The mRNA expression of miR-627 was detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. The 3rd to 5th passages of fibroblasts (Fbs) were isolated from hypertrophic scar tissue and cultured for subsequent experiments after identification. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic group, and miR-627 inhibitor group. The corresponding sequences were transfected respectively. At 0 (immediately), 12, 24, 36, and 48 h after transfection, the cell viability was detected by thiazolyl blue method; at 24 h after transfection, the apoptosis was detected by flow cytometry; at 24 h after transfection, the protein expression levels of insulin-like growth factor Ⅰ (IGF-Ⅰ), type Ⅰ collagen, and α smooth muscle actin (α-SMA) were detected by Western blotting. Two batches of Fbs from hypertrophic scar were used, one batch was divided into IGF-Ⅰ wild type+miR-627 negative control group and IGF-Ⅰ wild type+miR-627 mimic group, and the other batch was divided into IGF-Ⅰ mutant+miR-627 negative control group and IGF-Ⅰ mutant+miR-627 mimic group. The corresponding sequences were transfected respectively. At 48 h after transfection, the expressions of luciferase and renal luciferase were detected by luciferase reporter gene detection kit, and the ratio of the two was calculated to reflect the activity of IGF-Ⅰ. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic alone group, and miR-627 mimic+IGF-Ⅰ group, and were transfected with the corresponding sequences respectively. At 24 h after transfection, the protein expression levels of IGF-Ⅰ, type Ⅰ collagen, and α-SMA were detected by Western blotting. The number of samples in cell experiment was 3. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, independent sample t test, and chi-square test. Results: The expression of miR-627 mRNA in hypertrophic scar tissue was 0.47±0.06, which was significantly lower than 1.12±0.23 in normal skin tissue (t=15.090, P<0.01). At 12, 24, 36, and 48 hours after transfection, the cell viability of miR-627 mimic group was significantly lower than that of miR-627 negative control group (t=9.918, 34.370, 13.580, 61.550, P<0.05 or P<0.01); the cell viability of miR-627 inhibitor group was significantly higher than that of miR-627 negative control group (t=4.722, 8.616, 13.330, 14.000, P<0.05 or P<0.01). At 24 h after transfection, compared with the apoptosis rate (8.42±0.47)% in miR-627 negative control group, (10.89±0.35)% in miR-627 mimic group was significantly higher (t=7.301, P<0.01), and (5.00±0.22)% in miR-627 inhibitor group was significantly lower (t=11.510, P<0.01). At 24 h after transfection, compared with the cell protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA in miR-627 negative control group, those in miR-627 mimic group were significantly lower (t=25.470, 5.282, 7.415, P<0.01), and those in miR-627 inhibitor group were significantly higher (t=15.930, 8.857, 9.763, P<0.01). At 48 h after transfection, the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ wild type+miR-627 mimic group was 0.463±0.061, which was significantly lower than 0.999±0.011 in IGF-Ⅰ wild type+miR-627 negative control group (t=16.852, P<0.01); the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ mutant+miR-627 mimic group was 0.934±0.021, which was similar to 0.930±0.023 in IGF-Ⅰ mutant+miR-627 negative control group (t=1.959, P>0.05). At 24 h after transfection, the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in miR-627 mimic alone group were 1.623±0.070, 1.363±0.042, and 1.617±0.025, which were significantly lower than 2.723±0.045, 2.147±0.067, and 2.533±0.055 in miR-627 negative control group (t=22.831, 7.280, 26.220, P<0.01); the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in mimic+IGF-Ⅰ group were 2.477±0.102, 1.760±0.046, and 2.387±0.049, which were significantly higher than those of miR-627 mimic alone group (t=3.830, 8.286, 3.436, P<0.05 or P<0.01). Conclusions: miR-627 expression in human hypertrophic scars is down-regulated; miR-627 can inhibit the proliferation and promote the apoptosis of Fbs in human hypertrophic scar by targeted inhibition of IGF-Ⅰ expression.