Adipose-derived stromal/stem cells successfully attenuate the fibrosis of scleroderma mouse models

Adipose-derived stem cells in immune-related skin disease: a review of current research and underlying mechanisms

Adipose-derived stem cells (ASCs) are a critical adult stem cell subpopulation and are widely utilized in the fields of regenerative medicine and stem cell research due to their abundance, ease of harvest, and low immunogenicity. ASCs, which are homologous with skin by nature, can treat immune-related skin diseases by promoting skin regeneration and conferring immunosuppressive effects, with the latter being the most important therapeutic mechanism. ASCs regulate the immune response by direct cell-cell communication with immune cells, such as T cells, macrophages, and B cells. In addition to cell-cell interactions, ASCs modulate the immune response indirectly by secreting cytokines, interleukins, growth factors, and extracellular vesicles. The immunomodulatory effects of ASCs have been exploited to treat many immune-related skin diseases with good therapeutic outcomes. This article reviews the mechanisms underlying the immunomodulatory effects of ASCs, as well as progress in research on immune-related skin diseases.

Mesenchymal stem cell-based therapy for autoimmune-related fibrotic skin diseases-systemic sclerosis and sclerodermatous graft-versus-host disease

BACKGROUND

Systemic sclerosis (SSc) and sclerodermatous graft-versus-host disease (Scl-GVHD)-characterized by similar developmental fibrosis, vascular abnormalities, and innate and adaptive immune response, resulting in severe skin fibrosis at the late stage-are chronic autoimmune diseases of connective tissue. The significant immune system dysfunction, distinguishing autoimmune-related fibrosis from mere skin fibrosis, should be a particular focus of treating autoimmune-related fibrosis. Recent research shows that innovative mesenchymal stem cell (MSC)-based therapy, with the capacities of immune regulation, inflammation suppression, oxidation inhibition, and fibrosis restraint, shows great promise in overcoming the disease.

MAIN BODY

This review of recent studies aims to summarize the therapeutic effect and theoretical mechanisms of MSC-based therapy in treating autoimmune-related fibrotic skin diseases, SSc and Scl-GVHD, providing novel insights and references for further clinical applications. It is noteworthy that the efficacy of MSCs is not reliant on their migration into the skin. Working on the immune system, MSCs can inhibit the chemotaxis and infiltration of immune cells to the skin by down-regulating the expression of skin chemokines and chemokine receptors and reducing the inflammatory and pro-fibrotic mediators. ​Furthermore, to reduce levels of oxidative stress, MSCs may improve vascular abnormalities, and enhance the antioxidant defenses through inducible nitric oxide synthase, thioredoxin 1, as well as other mediators. The oxidative stress environment does not weaken MSCs and may even strengthen certain functions. Regarding fibrosis, MSCs primarily target the transforming growth factor-β signaling pathway to inhibit fibroblast activation. Here, miRNAs may play a critical role in ECM remodeling. Clinical studies have demonstrated the safety of these approaches, though outcomes have varied, possibly owing to the heterogeneity of MSCs, the disorders themselves, and other factors. Nevertheless, the research clearly reveals the immense potential of MSCs in treating autoimmune-related fibrotic skin diseases.

CONCLUSION

The application of MSCs presents a promising approach for treating autoimmune-related fibrotic skin diseases: SSc and Scl-GVHD. Therapies involving MSCs and MSC extracellular vesicles have been found to operate through three primary mechanisms: rebalancing the immune and inflammatory disorders, resisting oxidant stress, and inhibiting overactivated fibrosis (including fibroblast activation and ECM remodeling). However, the effectiveness of these interventions requires further validation through extensive clinical investigations, particularly randomized control trials and phase III/IV clinical trials. Additionally, the hypothetical mechanism underlying these therapies could be elucidated through further research.

Progress in research on mesenchymal stem cells and their extracellular vesicles for treating fibrosis in systemic sclerosis

Systemic sclerosis (SSc) refers to an autoimmune disease characterized by immune dysfunction, vascular endothelial damage, and multi-organ fibrosis. Thus far, this disease is incurable, and its high mortality rate is significantly correlated with fibrotic events. Fibrosis has been confirmed as a difficult clinical treatment area that should be urgently treated in clinical medicine. Mesenchymal stem cells (MSCs) exhibit immunomodulatory, pro-angiogenic, and anti-fibrotic functions. MSCs-derived extracellular vesicles (EVs) have aroused rising interest as a cellular component that retains the functions of MSCs while circumventing the possible adverse effects of MSCs. Moreover, EVs have great potential in treating SSc. In this study, the current research progress on MSCs and their EVs for treating fibrosis in SSc was reviewed, with an aim to provide some reference for future MSCs and their EVs in treating SSc.

Engineered elastin-like polypeptide improves the efficiency of adipose-derived stem cell-mediated cutaneous wound healing in type II diabetes mellitus

Impaired cutaneous wound healing is a major complication in patients with diabetes mellitus (DM), leading to increased amputation and mortality rates in affected patients. Adipose-derived stem cells (ASCs) are widely used seed cells for promoted tissue regeneration to improve wound closure under diabetic conditions. However, ASCs-based therapies remain limited due to difficulties in maintaining cell quality during transplantation. To overcome this problem, extracellular matrix mimetic biomaterials have been developed for use in biomedical engineering field, including tissue engineering and regenerative medicine. Herein, a biosynthesized arginine-glycine-aspartate amino acid residues (RGD motif, known as a cell adhesion motif)-containing elastin-like polypeptides (REPs) improved the efficacy of ASCs in enhancing wound closure and skin elasticity in diabetic wounds by promoting the expression of angiogenic growth factors. Therefore, REPs can be used as potential supplements to stem cell-based therapeutic approach to accelerate diabetic wound repair.

Systemic therapy in juvenile localized scleroderma

INTRODUCTION

Juvenile localized scleroderma (JLS) is a rare sclerosing disorder of childhood which can result in permanent morbidity and functional disability, if not effectively treated. Treatment should be started in the inflammatory phase before the development of any complication and/or damage.

AREAS COVERED

In this review, we will discuss how to assess disease activity and damage in JLS, and propose an escalation plan for systemic treatment, according to a treat-to-target concept. We will discuss the definition of inactive disease and how and when to discontinue medications.

EXPERT OPINION

Before starting treatment, it is extremely important to assess baseline disease activity for treatment response to be adequately checked. Moreover, the activity of the extra cutaneous involvement is an important part of the assessment. Patients should be treated in the 'therapeutic window,' before significant fibrosis results. Most patients should receive systemic treatments; in these patients, Methotrexate should be used as the first-line disease-modifying anti-rheumatic drug (DMARD). However, methotrexate intolerance or non-response is an issue, and these patients should be proposed a treatment escalation according to results of latest studies. Future research can develop better prognostic markers to help to guide our decision.

Advancements in adipose-derived stem cell therapy for skin fibrosis

Pathological scarring and scleroderma, which are the most common conditions of skin fibrosis, pathologically manifest as fibroblast proliferation and extracellular matrix (ECM) hyperplasia. Fibroblast proliferation and ECM hyperplasia lead to fibrotic tissue remodeling, causing an exaggerated and prolonged wound-healing response. The pathogenesis of these diseases has not been fully clarified and is unfortunately accompanied by exceptionally high medical needs and poor treatment effects. Currently, a promising and relatively low-cost treatment has emerged-adipose-derived stem cell (ASC) therapy as a branch of stem cell therapy, including ASCs and their derivatives-purified ASC, stromal vascular fraction, ASC-conditioned medium, ASC exosomes, etc., which are rich in sources and easy to obtain. ASCs have been widely used in therapeutic settings for patients, primarily for the defection of soft tissues, such as breast enhancement and facial contouring. In the field of skin regeneration, ASC therapy has become a hot research topic because it is beneficial for reversing skin fibrosis. The ability of ASCs to control profibrotic factors as well as anti-inflammatory and immunomodulatory actions will be discussed in this review, as well as their new applications in the treatment of skin fibrosis. Although the long-term effect of ASC therapy is still unclear, ASCs have emerged as one of the most promising systemic antifibrotic therapies under development.

Adipose Tissue and Adipose-Tissue-Derived Cell Therapies for the Treatment of the Face and Hands of Patients Suffering from Systemic Sclerosis

Adipose tissue is recognized as a valuable source of cells with angiogenic, immunomodulatory, reparative and antifibrotic properties and emerged as a therapeutic alternative for the regeneration and repair of damaged tissues. The use of adipose-tissue-based therapy is expanding in autoimmune diseases, particularly in Systemic Sclerosis (SSc), a disease in which hands and face are severely affected, leading to disability and a decrease in quality of life. Combining the advantage of an abundant supply of fat tissue and a high abundance of stem/stromal cells, fat grafting and adipose tissue-derived cell-based therapies are attractive therapeutic options in SSc. This review aims to synthesize the evidence to determine the effects of the use of these biological products for face and hands treatment in the context of SSc. This highlights several points: the need to use relevant effectiveness criteria taking into account the clinical heterogeneity of SSc in order to facilitate assessment and comparison of innovative therapies; second, it reveals some impacts of the disease on fat-grafting success; third, an important heterogeneity was noticed regarding the manufacturing of the adipose-derived products and lastly, it shows a lack of robust evidence from controlled trials comparing adipose-derived products with standard care.

Mesenchymal stem cells alleviate systemic sclerosis by inhibiting the recruitment of pathogenic macrophages

Systemic sclerosis (SSc) is a recalcitrant autoimmune disease for which there is no cure. Mesenchymal stem cell (MSC)-based treatment has emerged as a promising therapeutic option for several autoimmune diseases. Previously, we found that the immunoregulatory potential of MSCs can be greatly enhanced by IFN-γ and TNF-α. Here, we found that IFN-γ- and TNF-α-pretreated MSCs significantly alleviated skin fibrosis in a bleomycin (BLM)-induced SSc model. Macrophages were found to be the predominant profibrotic immune cell population in the pathogenesis of SSc. The accumulation of macrophages was significantly decreased by MSC treatment. Importantly, MSCs primarily reduced the population of maturing macrophages with high CCR2 expression by inhibiting the generation of CCL2 from fibroblasts and macrophages. This finding may help to improve MSC-based clinical treatments for SSc patients.

Mesenchymal stem cells and connective tissue diseases: From bench to bedside

The pathogenesis of connective tissue diseases (CTDs), represented by systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), primary Sjögren’s syndrome (pSS), and idiopathic inflammatory myopathies (IIM), includes various immune cells involved in both innate and adaptive immunity. The mesenchymal stem cells (MSCs) are unique due to their regulatory effect on immunity. This makes them a promising therapeutic approach for patients with immune-mediated disorders such as CTD. The safety and clinical efficacy of MSC treatment in CTD have been tested in a growing number of preclinical and clinical studies. Administration of MSCs has consistently shown benefits with both symptomatic and histologic improvement in CTD animal models. MSC therapies in severe and drug-resistant CTD patients have shown promise in a number of the pilot studies, cohort studies, and randomized controlled trials in SLE, RA, and SSc, but some problems still need to be resolved in the transition from the bench to the bedside. The relevant studies in pSS and IIM are still in their infancy, but have displayed encouraging outcomes. Considerable efficacy variations have been observed in terms of the route of delivery, time of MSC injection, origin of the MSCs and dosage. Furthermore, the optimization of conventional drugs combined with MSC therapies and the applications of novel cell engineering approaches requires additional research. In this review, we summarize the current evidence about the immunoregulatory mechanism of MSCs, as well as the preclinical and clinical studies of MSC-based therapy for the treatment of CTDs.

Therapeutic effects of adipose-derived mesenchymal stem/stromal cells with enhanced migration ability and hepatocyte growth factor secretion by low-molecular-weight heparin treatment in bleomycin-induced mouse models of systemic sclerosis

Background

Adipose-derived mesenchymal stem cells (ASCs) have gained attention as a new treatment for systemic sclerosis (SSc). Low-molecular-weight heparin (LMWH) enhances cell function and stimulates the production of hepatocyte growth factor (HGF) in a variety of cells. This study investigated the effects of LMWH on the functions of mouse ASCs (mASCs), and the therapeutic effects of mASCs activated with LMWH (hep-mASCs) in mouse models of SSc.

Methods

The cellular functions of mASCs cultured with different concentrations of LMWH were determined. Mice were divided into four groups: bleomycin (BLM)-induced SSc (BLM-alone), BLM-induced SSc administered with mASCs (BLM-mASC), and BLM-induced SSc administered with mASCs activated with 10 or 100 μg/mL LMWH (BLM-hep-mASC); there were 9 mice per group (n = 9). Skin inflammation and fibrosis were evaluated using histological and biochemical examinations and gene expression levels.

Results

In vitro assays showed that migration ability and HGF production were significantly higher in hep-mASCs than in mASCs alone. The mRNA expression levels of cell migration factors were significantly upregulated in hep-mASCs compared to those in mASCs alone. The hep-mASCs accumulated in the skin tissues more than mASCs alone. The thickness of skin and hydroxyproline content in BLM-hep-mASC groups were significantly decreased, and the skin mRNA expression levels of interleukin-2, α-smooth muscle actin, transforming growth factor β1, collagen type 1 alpha 1, and tissue inhibitor of metalloproteinase 2 were significantly downregulated compared to those in the BLM-alone group.

Conclusions

hep-mASCs showed higher anti-inflammatory and anti-fibrotic effects than mASCs alone and may be a promising candidate for SSc treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02915-6.

Anti-vinculin antibodies as a novel biomarker in Egyptian patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune disorder that causes vasculopathy and scarring, most commonly in the lungs and skin, but it can also affect other organs. Endothelial vinculin plays a critical role in angiogenesis regulation. Therefore, vinculin overexpression in SSc may give rise to anti-vinculin antibodies, which may contribute to the development of SSc vasculopathy. The current research aims to (1) determine whether anti-vinculin autoantibodies play a significant role in the diagnosis of SSc and (2) compare anti-vinculin serum levels between two scleroderma patient populations, namely, pulmonary artery hypertension (PAH)-predominant and interstitial pulmonary fibrosis (IPF)-predominant groups.

METHODS

This research included 140 participants categorized into three groups: group I-patients with PAH-predominant; group II-patients with ILD-predominant; group III-the control group. Anti-vinculin antibodies were detected in serum samples collected from all participants using ELISA. All subjects underwent high-resolution computed tomography (CT), diffusing capacity for carbon monoxide, and pulmonary function tests.

RESULTS

Patients in group I (PAH-predominant group, N = 35) were 41.3 [± 11.4] years old, with 80% being women. Patients in group II (ILD-predominant group, N = 35) were 41.0 [± 11.5] years old. The SSc group showed significantly higher anti-vinculin antibody levels than the control group (P < 0.001). The PAH-predominant group demonstrated significantly higher anti-vinculin antibody levels and anti-vinculin positivity than the ILD-predominant group.

CONCLUSION

Anti-vinculin antibodies in the blood appear to be diagnostic biomarkers for scleroderma. Furthermore, they shed light on some novel perspectives on the pathophysiology of specific lung fibrotic changes. Key Points • This study included two groups of systemic sclerosis patients (PAH-predominant group, ILD-predominant group) as well as a control group to investigate the significance of anti-vinculin antibodies in such cases. • Our results have demonstrated that anti-vinculin antibodies can play a significant role in diagnosing and monitoring systemic sclerosis disease.

Effect of Adipose-Derived Stem Cell on Collagen Deposition in Nude Mouse Model of Scleroderma

Systemic sclerosis is an autoimmune disease featured by uncontrolled fibrosis and collagen deposition. This study aimed to investigate the impact of adipose-derived stem cells (ADSCs) transplantation on collagen in scleroderma. After establishment of scleroderma model using Bleomycin, the animals received subcutaneous injection of 0.3 ml fat (group B) or 0.3 ml fat+1×106 ADSCs (group C), or 1×106 ADSCs alone (group D). Mice treated with PBS were taken as control group (group A). One month after operation, the skin tissue at injection site was collected for H&E staining, and immunohistochemistry to determine the content of TGF-β1 and type III collagen. Compared to control group, group B, C, and D exhibited improvement in collagen deposition and reduction in TGF-β1 content and type III collagen. Combined graft of fat and ADSCs exerted more significant effect compared to single ADSCs treatment. In conclusion, fat and ADSCs transplantation improves collagen deposition in nude mice with scleroderma and the combined treatment exerts a higher efficacy, suggesting that ADSCs need adipose carrier and microenvironment. These findings provide a novel insight into the treatment of scleroderma.

Application of an iPSC-Derived Organoid Model for Localized Scleroderma Therapy

Localized scleroderma (LoS) is a rare chronic disease with extensive tissue fibrosis, inflammatory infiltration, microvascular alterations, and epidermal appendage lesions. However, a deeper understanding of the pathogenesis and treatment strategies of LoS is currently limited. In the present work, a proteome map of LoS skin is established, and the pathological features of LoS skin are characterized. Most importantly, a human-induced pluripotent stem cell-derived epithelial and mesenchymal (EM) organoids model in a 3D culture system for LoS therapy is established. According to the findings, the application of EM organoids on scleroderma skin can significantly reduce the degree of skin fibrosis. In particular, EM organoids enhance the activity of epidermal stem cells in the LoS skin and promotes the regeneration of sweat glands and blood vessels. These results highlight the potential application of organoids for promoting the recovery of scleroderma associated phenotypes and skin-associated functions. Furthermore, it can provide a new therapeutic alternative for patients suffering from disfigurement and skin function defects caused by LoS.

Application of adipose-derived stem cells in treating fibrosis

Fibrosis is the hyperactivation of fibroblasts that results in excessive accumulation of extracellular matrix, which is involved in numerous pathological changes and diseases. Adipose-derived stem cells (ASCs) are promising seed cells for regenerative medicine due to their bountiful source, low immunogenicity and lack of ethical issues. Their anti-fibrosis, immunomodulation, angiogenesis and other therapeutic effects have made them suitable for treating fibrosis-related diseases. Here, we review the literature on ASCs treating fibrosis, elaborate and discuss their mechanisms of action, changes in disease environment, ways to enhance therapeutic effects, as well as current preclinical and clinical studies, in order to provide a general picture of ASCs treating fibrotic diseases.

The Therapeutic Effects of Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells on Scleroderma

Background:

Scleroderma is a multisystem disease in which tissue fibrosis is caused by inflammation and vascular damage. The mortality of scleroderma has remained high due to a lack of effective treatments. However, exosomes derived from human umbilical cord mesenchymal stem cells (HUMSCs)-Ex have been regarded as potential treatments for various autoimmune diseases, and may also act as candidates for treating scleroderma.

Methods:

Mice with scleroderma received a single 50 μg HUMSCs-Ex. HUMSCs-Ex was characterized using transmission electron microscopy, nanoparticle tracking analysis and nanoflow cytometry. The therapeutic efficacy was assessed using histopathology, immunohistochemistry, immunofluorescence, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay and western blot.

Results:

HUMSCs-Ex ameliorated the deposition of extracellular matrix and suppressed the epithelial-mesenchymal transition process, and the effects lasted at least three weeks. In addition, HUMSCs-Ex promoted M1 macrophage polarization and inhibited M2 macrophage polarization, leading to the restoration of the balance of M1/M2 macrophages.

Conclusion:

We investigated the potential antifibrotic and anti-inflammatory effects of HUMSCs-Ex in a bleomycin-induced mouse model of scleroderma. So HUMSCs-Ex could be considered as a candidate therapy for scleroderma.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13770-021-00405-5.

Reversible alopecia in En Coup de Sabre morphea

En coup de sabre form of morphea often affects the scalp with thickening, sclerosis, dyspigmentation, and scarring alopecia. Traditionally, it has been thought that the alopecia is not responsive to treatment and permanent. This report presents two cases with extensive, apparent scarring alopecia that improved with medical treatment.

Multiplex Immunofluorescence for Detection of Spatial Distributions of Infiltrating T Cells Within Different Regions of Hepatic Lobules During Liver Transplantation Rejection

It remains unclear as to whether there are differences that exist in the types and functional status of immune cells within different areas of the liver lobules after rejection of liver transplantation. The composition of infiltrating T cells in liver allografts during liver transplantation rejection is indistinct and difficult to visualize within the same biopsy slide. In an attempt to rectify this problem, we applied multiplex immunofluorescent assays to assess the spatial distribution of various types of infiltrating T cells in different areas of the liver lobules after liver transplantation. In identical areas of the hepatic lobules, the percentage of CD4⁺ T, CD8⁺ T, and regulatory T (Treg) cells in the rejection group was greater than that observed in the non-rejection and normal groups. Within all three groups, the percentage of CD4⁺ T, CD8⁺ T, and Treg cells from the periportal to perivenous zones initially increased and then decreased. In the rejection group, the percentage of CD8⁺ T cells gradually increased from the periportal to perivenous zones, with maximal levels in the perivenous as compared with that in the transitional and periportal zones. In conclusion, levels of CD8⁺ T cells within different regions of liver lobules are closely related to levels of rejection after liver transplantation. Liver transplantation rejection may be linked with increases in CD8⁺ T cells within the perivenous zone. Although the regional percent of increase in CD4⁺ T cells may not reflect level of the rejection, the overall numbers of both of CD4⁺ and CD8⁺ T cells within different regions were closely related to rejection levels.

Perspective on Stem Cell Therapy in Organ Fibrosis: Animal Models and Human Studies

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) components that result from the disruption of regulatory processes responsible for ECM synthesis, deposition, and remodeling. Fibrosis develops in response to a trigger or injury and can occur in nearly all organs of the body. Thus, fibrosis leads to severe pathological conditions that disrupt organ architecture and cause loss of function. It has been estimated that severe fibrotic disorders are responsible for up to one-third of deaths worldwide. Although intensive research on the development of new strategies for fibrosis treatment has been carried out, therapeutic approaches remain limited. Since stem cells, especially mesenchymal stem cells (MSCs), show remarkable self-renewal, differentiation, and immunomodulatory capacity, they have been intensively tested in preclinical studies and clinical trials as a potential tool to slow down the progression of fibrosis and improve the quality of life of patients with fibrotic disorders. In this review, we summarize in vitro studies, preclinical studies performed on animal models of human fibrotic diseases, and recent clinical trials on the efficacy of allogeneic and autologous stem cell applications in severe types of fibrosis that develop in lungs, liver, heart, kidney, uterus, and skin. Although the results of the studies seem to be encouraging, there are many aspects of cell-based therapy, including the cell source, dose, administration route and frequency, timing of delivery, and long-term safety, that remain open areas for future investigation. We also discuss the contemporary status, challenges, and future perspectives of stem cell transplantation for therapeutic options in fibrotic diseases as well as we present recent patents for stem cell-based therapies in organ fibrosis.

Mesenchymal Stem Cell-Derived Exosomes Ameliorate Dermal Fibrosis in a Murine Model of Bleomycin-Induced Scleroderma

Mesenchymal stem cells (MSCs) have become a promising therapeutic strategy for scleroderma. Exosomes derived from MSCs (MSC-exosomes) possess functional properties similar to those of their source cells. In this study, we aimed to explore the potential role of MSC-exosomes in the treatment of scleroderma. MSC-exosomes were isolated from human umbilical cords through ultracentrifugation and characterized. An experimental fibrosis model was established in BALB/c mice by a subcutaneous injection of bleomycin, followed by treatment with MSC-exosomes or MSC infusions once a week for a total of four doses. Using hematoxylin and eosin and Masson's trichrome staining and immunohistochemistry, hydroxyproline content, and quantitative real-time polymerase chain reaction analyses, we investigated the effects of MSC-exosomes on dermal fibrosis and explored the underlying mechanism. MSC-exosome treatment restored the dermal architecture, reduced dermal thickness, and partially increased subcutaneous adipose tissue thickness. In addition, MSC-exosomes inhibited the expression of collagen (COL)-I, COL-III, and α-smooth muscle actin. The transforming growth factor (TGF)-β/Smad signaling pathway was also suppressed in MSC-exosome-treated mice. Taken together, our results suggest that MSC-exosomes can attenuate myofibroblast activation and collagen deposition in dermal fibrosis by downregulating the TGF-β/Smad signaling pathway. Therefore, the use of MSC-exosomes may be a potential therapeutic approach for the treatment of scleroderma.

Adipose-derived stem cells: Pathophysiologic implications vs therapeutic potential in systemic sclerosis

Adipose-derived stem cells (ADSCs) residing in the stromal vascular fraction (SVF) of white adipose tissue are recently emerging as an alternative tool for stem cell-based therapy in systemic sclerosis (SSc), a complex connective tissue disorder affecting the skin and internal organs with fibrotic and vascular lesions. Several preclinical and clinical studies have reported promising therapeutic effects of fat grafting and autologous SVF/ADSC-based local treatment for facial and hand cutaneous manifestations of SSc patients. However, currently available data indicate that ADSCs may represent a double-edged sword in SSc, as they may exhibit a pro-fibrotic and anti-adipogenic phenotype, possibly behaving as an additional pathogenic source of pro-fibrotic myofibroblasts through the adipocyte-to-myofibroblast transition process. Thus, in the perspective of a larger employ of SSc-ADSCs for further therapeutic applications, it is important to definitely unravel whether these cells present a comparable phenotype and similar immunosuppressive, anti-inflammatory, anti-fibrotic and pro-angiogenic properties in respect to healthy ADSCs. In light of the dual role that ADSCs seem to play in SSc, this review will provide a summary of the most recent insights into the preclinical and clinical studies employing SVF and ADSCs for the treatment of the disease and, at the same time, will focus on the main findings highlighting the possible involvement of these stem cells in SSc-related fibrosis pathogenesis.

Targeted delivery in scleroderma fibrosis

Systemic sclerosis (SSc) is considered one of the most challenging and difficult to treat among rheumatic disorders, due to its severity, multiorgan manifestation and different outcomes. It manifests fibrosis in different organs, mostly in skin and lungs. The skin fibrosis expression is considered the first sign of the disease and usually it is followed by internal organ fibrosis. An aberrant immune system activation seems to relate to the expression of the disease, but even environmental influences and dysregulation of many molecules signalling pathways are involved in the development of the disease. Current therapies are limited and characterized by multiple side effects: systemic route is the elective administration route, which decreases patient adherence to the therapy, as they are often already bothered by pain and disfigurement. Treatments available are organ-based, originally indicated for other conditions and there is no therapy available to reduce the fibroblast population size within existing fibrotic lesions. Disease-modifying therapies or immunomodulatory agents that are highly effective in other rheumatic diseases have shown disappointing results in SSc. There are thus no standardized and effective treatments for this disease, and there are even unanswered questions related to the insurgence of the pathology and all the mechanisms involved. An ideal approach could be considered "targeted therapy" that will be an increasingly attainable objective insofar as our understanding of the disease improves. The advantages in identifying the molecule and the signalling pathways involved in the pathology have helped to find some novel compounds for the therapy of scleroderma fibrosis or following innovative uses for already-approved drugs, corroborated by many clinical studies.

Mesenchymal stem cell as a novel approach to systemic sclerosis; current status and future perspectives

Systemic sclerosis is a rare chronic autoimmune disease with extensive microvascular injury, damage of endothelial cells, activation of immune responses, and progression of tissue fibrosis in the skin and various internal organs. According to epidemiological data, women's populations are more susceptible to systemic sclerosis than men. Until now, various therapeutic options are employed to manage the symptoms of the disease. Since stem cell-based treatments have developed as a novel approach to rescue from several autoimmune diseases, it seems that stem cells, especially mesenchymal stem cells as a powerful regenerative tool can also be advantageous for systemic sclerosis treatment via their remarkable properties including immunomodulatory and anti-fibrotic effects. Accordingly, we discuss the contemporary status and future perspectives of mesenchymal stem cell transplantation for systemic sclerosis.

Adipose-Derived Stem Cells Promote Intussusceptive Lymphangiogenesis by Restricting Dermal Fibrosis in Irradiated Tissue of Mice

Currently, there is no definitive treatment for lymphatic disorders. Adipose-derived stem cells (ADSCs) have been reported to promote lymphatic regeneration in lymphedema models, but the mechanisms underlying the therapeutic effects remain unclear. Here, we tested the therapeutic effects of ADSC transplantation on lymphedema using a secondary lymphedema mouse model. The model was established in C57BL/6J mice by x-irradiation and surgical removal of the lymphatic system in situ. The number of lymphatic vessels with anti-lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) immunoreactivity increased significantly in mice subjected to transplantation of 7.5 × 10⁵ ADSCs. X-irradiation suppressed lymphatic vessel dilation, which ADSC transplantation could mitigate. Proliferative cell nuclear antigen staining showed increased lymphatic endothelial cell (LEC) and extracellular matrix proliferation. Picrosirius red staining revealed normal collagen fiber orientation in the dermal tissue after ADSC transplantation. These therapeutic effects were not related to vascular endothelial growth factor (VEGF)-C expression. Scanning electron microscopy revealed structures similar to the intraluminal pillar during intussusceptive angiogenesis on the inside of dilated lymphatic vessels. We predicted that intussusceptive lymphangiogenesis occurred in lymphedema. Our findings indicate that ADSC transplantation contributes to lymphedema reduction by promoting LEC proliferation, improving fibrosis and dilation capacity of lymphatic vessels, and increasing the number of lymphatic vessels via intussusceptive lymphangiogenesis.