Fibrosis Development in HOCl-Induced Systemic Sclerosis: A Multistage Process Hampered by Mesenchymal Stem Cells

IBPA a mutual prodrug of ibuprofen and acetaminophen alleviates inflammation, immune dysregulation and fibrosis in preclinical models of systemic sclerosis

Systemic sclerosis (SSc) is a devastating autoimmune illness with a wide range of clinical symptoms, including vascular abnormalities, inflammation, and persistent and progressive fibrosis. The disease's complicated pathophysiology makes it difficult to develop effective therapies, necessitating research into novel therapeutic options. Molecular hybridization is a strategy that can be used to develop new drugs that act on two or multiple targets and represents an interesting option to be explored for the treatment of complex diseases. We aimed to evaluate the effects of a hybrid mutual prodrug of ibuprofen and acetaminophen (IBPA) in peripheral blood mononuclear cells (PBMC) isolated from SSc patients, and in an in vivo model of SSc induced in BALB/c mice by intradermal injections of hypochlorous acid (HOCl) for 6 weeks. The mice were treated at the same time with daily intraperitoneal injections of IBPA (40 mg/kg). Pulmonary and skin fibrosis as well as immune responses were evaluated. IBPA significantly decreased the release of cytokines in PBMC culture supernatants from SSc patients after stimulation with phytohemagglutinin-M (IL-2, IL-4, IL-6, IL-10, IL-13, IL-17A, TNF and IFN-γ).In HOCl-induced SSc, IBPA treatment prevented dermal and pulmonary fibrosis, in addition to reducing CD4 + T and B cells activation and reversing the M2 polarization of macrophages in spleen cells, and inhibiting IFN-γ secretion in splenocyte cultures. These results show the anti-inflammatory and antifibrotic effects of IBPA in SSc and highlight the therapeutic potential of this mutual prodrug, providing support for future studies.

The Potential of Twendee X® as a Safe Antioxidant Treatment for Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by systemic skin hardening, which combines Raynaud's phenomenon and other vascular disorders, skin and internal organ fibrosis, immune disorders, and a variety of other abnormalities. Symptoms vary widely among individuals, and personalized treatment is sought for each patient. Since there is no fundamental cure for SSc, it is designated as an intractable disease with patients receiving government subsidies for medical expenses in Japan. Oxidative stress (OS) has been reported to play an important role in the cause and symptoms of SSc. HOCl-induced SSc mouse models are known to exhibit skin and visceral fibrosis, vascular damage, and autoimmune-like symptoms observed in human SSc. The antioxidant combination Twendee X® (TwX) is a dietary supplement consisting of vitamins, amino acids, and CoQ10. TwX has been proven to prevent dementia in humans with mild cognitive impairment and significantly improve cognitive impairment in an Alzheimer's disease mouse model by regulating OS through a strong antioxidant capacity that cannot be achieved with a single antioxidant ingredient. We evaluated the effectiveness of TwX on various symptoms of HOCl-induced SSc mice. TwX-treated HOCl-induced SSc mice showed significantly reduced lung and skin fibrosis compared to untreated HOCl-induced SSc mice. TwX also significantly reduced highly oxidized protein products (AOPP) in serum and suppressed Col-1 gene expression and activation of B cells involved in autoimmunity. These findings suggest that TwX has the potential to be a new antioxidant treatment for SSc without side effects.

PPARγ partial agonist LPSF/GQ-16 prevents dermal and pulmonary fibrosis in HOCl-induced systemic sclerosis (SSc) and modulates cytokine production in PBMC of SSc patients

Thiazolidinediones (TZD) are synthetic molecules that have a range of biological effects, including antifibrotic and anti-inflammatory, and they may represent a promising therapeutic strategy for systemic sclerosis (SSc). The aim of this study was to investigate the immunomodulatory and antifibrotic properties of LPSF/GQ-16, a TZD derivative, in peripheral blood mononuclear cells (PBMC) from SSc patients and in a murine model of SSc HOCl-induced. The PBMC of 20 SSc patients were stimulated with phytohemagglutinin (PHA) and treated with LPSF/GQ-16 for 48 h, later cytokines in the culture supernatants were quantified by sandwich enzyme-linked immunosorbent assay (ELISA) or cytometric bead array (CBA). Experimental SSc was induced by intradermal injections of hypochlorous acid (HOCl) for 6 weeks. HOCl-induced SSc mice received daily treatment with LPSF/GQ-16 (30 mg/kg) through intraperitoneal injections during the same period. Immunological parameters were evaluated by flow cytometry and ELISA, and dermal and pulmonary fibrosis were evaluated by RT-qPCR, hydroxyproline dosage and histopathological analysis. In PBMC cultures, it was possible to observe that LPSF/GQ-16 modulated the secretion of cytokines IL-2 (p < 0.001), IL-4 (p < 0.001), IL-6 (p < 0.001), IL-17A (p = 0.006), TNF (p < 0.001) and IFN-γ (p < 0.001). In addition, treatment with LPSF/GQ-16 in HOCl-induced SSc mice promoted a significant reduction in dermal thickening (p < 0.001), in the accumulation of collagen in the skin (p < 0.001), down-regulated the expression of fibrosis markers in the skin (Col1a1, α-Sma and Tgfβ1, p < 0.001 for all) and lungs (Il4 and Il13, p < 0.001 for both), as well as reduced activation of CD4 + T cells (p < 0.001), B cells (p < 0.001) and M2 macrophages (p < 0.001). In conclusion, LPSF/GQ-16 showed immunomodulatory and antifibrotic properties, demonstrating the therapeutic potential of this molecule for SSc.

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.

Superiority of systemic bleomycin to intradermal HOCl for the study of interstitial lung disease

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, immune dysregulation, and multi-organ fibrosis. Interstitial lung disease (ILD) is a complication of SSc and a leading cause of SSc-death. The administration of hypochlorous acid (HOCl) intradermally in the mouse (HOCl-SSc) purportedly shows several features typical of SSc. We studied the model by injecting BALB/c mice daily intradermally with HOCl for 6-weeks, an exposure reported to induce lung fibrosis. On day 42, the skinfold thickness and the dermal thickness were two and three times larger respectively in the HOCl group compared to controls. HOCl treatment did not result in histological features of pulmonary fibrosis nor significant changes in lung compliance. Automated image analysis of HOCl mice lungs stained with picrosirius red did not show increased collagen deposition. HOCl injections did not increase pulmonary mRNA expression of pro-fibrotic genes nor induced the production of serum advanced oxidation protein products and anti-topoisomerase 1 antibodies. Immune cells in bronchoalveolar lavage fluid (BALF) and whole lung digests were not increased in HOCl-treated animals. Since lung fibrosis is proposed to be triggered by oxidative stress, we injected HOCl to Nrf2-/- mice, a mouse deficient in many antioxidant proteins. Lung compliance, histology, and BALF leukocyte numbers were comparable between Nrf2-/- mice and wild-type controls. We conclude that the HOCl-SSc model does not manifest SSc-lung disease.

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.

Mesenchymal stem cells suppressed skin and lung inflammation and fibrosis in topoisomerase I-induced systemic sclerosis associated with lung disease mouse model

Systemic sclerosis associated with lung interstitial lung disease (SSc-ILD) is the most common cause of death among patients with SSc. Mesenchymal stem cell (MSCs) transplantations had been treated by SSc patients that showed in the previous case report. The therapeutic mechanisms and effects of MSCs on SSc-ILD are still obscure. In this study, we investigated the therapeutic effects and mechanisms of treatment of BM-MSC derived from C57BL/6 on the topoisomerase I (TOPO I) induced SSc-ILD-like mice model. The mice were immunized with a mixture of recombinant human TOPO I in PBS solution (500 U/mL) and completed Freund's adjuvant [CFA; 1:1 (volume/volume)] twice per week for 9 weeks. On week 10, the mice were sacrificed to analyze the related pathological parameters. Lung and skin pathologies were analyzed using histochemical staining. CD4 T-helper (T_H) cell differentiation in lung and skin-draining lymph nodes was detected using flow cytometry. Our results revealed that allogeneic and syngeneic MSCs exhibited similar repressive effects on TOPO I-induced IgG1 and IgG2a in the SSc group. After intravascular (IV) treatment with syngeneic or allogeneic MSCs, the dermal thickness and fibrosis dramatically condensed and significantly reduced airway hyperresponsiveness. These findings showed that both allogeneic and syngeneic MSCs have therapeutic potential for SSc-ILD.

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.

Increased Expression of Galectin-3 in Skin Fibrosis: Evidence from In Vitro and In Vivo Studies

Skin fibrosis is a hallmark of a wide array of dermatological diseases which can greatly impact the patients' quality of life. Galectin-3 (GAL-3) has emerged as a central regulator of tissue fibrosis, playing an important pro-fibrotic role in numerous organs. Various studies are highlighting its importance as a skin fibrotic diseases biomarker; however, there is a need for further studies that clarify its role. This paper aims to ascertain whether the expression of GAL-3 is increased in relevant in vitro and in vivo models of skin fibrosis. We studied the role of GAL-3 in vitro using normal human dermal fibroblasts (NHDF) and fibrocytes. In addition, we used a skin fibrosis murine model (BALB/c mice) and human biopsies of healthy or keloid tissue. GAL-3 expression was analyzed using real time PCR, Western blot and immunostaining techniques. We report a significantly increased expression of GAL-3 in NHDF and fibrocytes cell cultures following stimulation with transforming growth factor β1 (TGFβ1). In vivo, GAL-3 expression was increased in a murine model of systemic sclerosis and in human keloid biopsies. In sum, this study underlines the involvement of GAL-3 in skin fibrosis using several models of the disease and highlights its role as a relevant target.

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.

The antifibrotic effects of naringin in a hypochlorous acid (HOCl)-induced mouse model of skin fibrosis

OBJECTIVES

Fibrosis is a chronic inflammation caused by the loss of innate compensational mechanisms. Naringin (NR) is a flavonoid with antineoplastic and anti-inflammatory effects. Here, we aimed to investigate the antifibrotic effects of NR and underlying mechanisms in a Hypochlorous acid (HOCl)-induced mouse model of skin fibrosis.

MATERIALS AND METHODS

A total of 24 six-week-old female BALB/c mice were randomly allocated into five groups: HOCl, Sham, PBS, HOCl + NR and DMSO and selected skin regions were treated for 6 weeks, until sacrifice. The histopathologic and collagenesis of skin resections were analyzed using H&E and PR staining. The mRNA levels of COL1, COL3 and αSMA genes were quantified. Serum samples were also used to evaluate TGF-β levels and LDH activity.

RESULTS

HOCl could increase the relative collagen content, while NR administration on HOCl-treated biopsies decreased collagenesis. COL1, COL3 and αSMA mRNA levels were significantly increased among HOCl-treated skin samples, while NR treatment could decrease these mRNA levels of genes to the extent equal to the levels in the Sham group. Similarly, Naringin-treated samples could decrease TGF-β levels.

CONCLUSIONS

We demonstrated that Naringin could exert protective effects against fibrotic complications of HOCL in skin tissue in vivo, by reducing the collagenesis and decreasing the levels of fibrosis-associated genes.

The Role of T Cells in Systemic Sclerosis: An Update

Systemic sclerosis (SSc) is a chronic disease characterized by microvasculopathy, autoantibodies (autoAbs), and fibrosis. The pathogenesis of the disease is incompletely understood. Microvasculopathy and autoAbs appear very early in the disease process. AutoAbs, such as those directed against DNA topoisomerase I (Topo I), are disease specific and associated with disease manifestations, and indicate activation of the adaptive immune system. B cells are involved in fibrosis in SSc. T cells are also involved in disease pathogenesis. T cells show signs of antigen-induced activation; T cells of TH2 type are increased and produce profibrotic cytokines interleukin (IL)-4, IL-13, and IL-31; CD4+ cytotoxic T lymphocytes are increased in skin lesions, and cause fibrosis and endothelial cell apoptosis; circulating T follicular helper (TFH) cells are increased in SSc produce IL-21 and promote plasmablast antibody production. On the other hand, regulatory T cells are impaired in SSc. These findings provide strong circumstantial evidence for T cell implication in SSc pathogenesis and encourage new T cell-directed therapeutic strategies for the disease.

Simple gene signature to assess murine fibroblast polarization

We provide an original multi-stage approach identifying a gene signature to assess murine fibroblast polarization. Prototypic polarizations (inflammatory/fibrotic) were induced by seeded mouse embryonic fibroblasts (MEFs) with TNFα or TGFß1, respectively. The transcriptomic and proteomic profiles were obtained by RNA microarray and LC-MS/MS. Gene Ontology and pathways analysis were performed among the differentially expressed genes (DEGs) and proteins (DEPs). Balb/c mice underwent daily intradermal injections of HOCl (or PBS) as an experimental murine model of inflammation-mediated fibrosis in a time-dependent manner. As results, 1456 and 2215 DEGs, and 289 and 233 DEPs were respectively found in MEFs in response to TNFα or TGFß1, respectively. Among the most significant pathways, we combined 26 representative genes to encompass the proinflammatory and profibrotic polarizations of fibroblasts. Based on principal component analysis, this signature deciphered baseline state, proinflammatory polarization, and profibrotic polarization as accurately as RNA microarray and LC-MS/MS did. Then, we assessed the gene signature on dermal fibroblasts isolated from the experimental murine model. We observed a proinflammatory polarization at day 7, and a mixture of a proinflammatory and profibrotic polarizations at day 42 in line with histological findings. Our approach provides a small-size and convenient gene signature to assess murine fibroblast polarization.

Mesenchymal Stem/Stromal Cells in Progressive Fibrogenic Involvement and Anti-Fibrosis Therapeutic Properties

Fibrosis refers to the connective tissue deposition and stiffness usually as a result of injury. Fibrosis tissue-resident mesenchymal cells, including fibroblasts, myofibroblast, smooth muscle cells, and mesenchymal stem/stromal cells (MSCs), are major players in fibrogenic processes under certain contexts. Acknowledging differentiation potential of MSCs to the aforementioned other types of mesenchymal cell lineages is essential for better understanding of MSCs’ substantial contributions to progressive fibrogenesis. MSCs may represent a potential therapeutic option for fibrosis resolution owing to their unique pleiotropic functions and therapeutic properties. Currently, clinical trial efforts using MSCs and MSC-based products are underway but clinical data collected by the early phase trials are insufficient to offer better support for the MSC-based anti-fibrotic therapies. Given that MSCs are involved in the coagulation through releasing tissue factor, MSCs can retain procoagulant activity to be associated with fibrogenic disease development. Therefore, MSCs’ functional benefits in translational applications need to be carefully balanced with their potential risks.

Mesenchymal Stem Cell-Based Therapy as a New Approach for the Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is an intractable autoimmune disease with unmet medical needs. Conventional immunosuppressive therapies have modest efficacy and obvious side effects. Targeted therapies with small molecules and antibodies remain under investigation in small pilot studies. The major breakthrough was the development of autologous haematopoietic stem cell transplantation (AHSCT) to treat refractory SSc with rapidly progressive internal organ involvement. However, AHSCT is contraindicated in patients with advanced visceral involvement. Mesenchymal stem cells (MSCs) which are characterized by immunosuppressive, antifibrotic and proangiogenic capabilities may be a promising alternative option for the treatment of SSc. Multiple preclinical and clinical studies on the use of MSCs to treat SSc are underway. However, there are several unresolved limitations and safety concerns of MSC transplantation, such as immune rejections and risks of tumour formation, respectively. Since the major therapeutic potential of MSCs has been ascribed to their paracrine signalling, the use of MSC-derived extracellular vesicles (EVs)/secretomes/exosomes as a "cell-free" therapy might be an alternative option to circumvent the limitations of MSC-based therapies. In the present review, we overview the current knowledge regarding the therapeutic efficacy of MSCs in SSc, focusing on progresses reported in preclinical and clinical studies using MSCs, as well as challenges and future directions of MSC transplantation as a treatment option for patients with SSc.

Therapeutic potential of mesenchymal stem cells for scleroderma induced in mouse model

OBJECTIVE

To examine the potential therapeutic effect of mesenchymal stem cells (MSCs) for experimental scleroderma.

MATERIALS AND METHODS

Fifty-four mice six-week-old (30-35 g) were studied. Hypochlorous acid (HOCl) induced scleroderma was considered. Mice were divided into 3 groups: (I) Control: Six mice did not receive any treatment and were sacrificed at the end of the experiment; (II) HOCl mice (induced scleroderma as a positive control): (III) MSCs-treated HOCl mice: Thirty six HOCl-induced mice were injected with MSCs (7.5 × 105) intravenous every week for 3 weeks. Skin pieces were taken from the backs of mice and lung tissue pieces. a smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β1) were analysed or fixed in 10 % formalin for skin and lung tissue histopathological analysis. Plasma nitric oxide (NO) was also assayed.

RESULTS

There was a significant rise in the NO level and of the cutaneous and lung tissue α-SMA and TGF-β1 in untreated scleroderma-induced mice. The values significantly normalized after MSC therapy over the 7 weeks duration of the study. The altered histopathology of the skin and lung tissues in the scleroderma-induced mice showed a remarkable tendency to normalization of the skin and lung parenchyma and vasculature.

CONCLUSION

There was a significant rise in the level of NO and skin and lung tissue α-SMA and TGF-β1 in untreated scleroderma-induced mice and values were significantly normalized after MSC therapy over the 7 weeks duration of the study. Altered histopathology of the skin and lung appeared nearly normal after MSC therapy.

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.

Mesenchymal stromal cells for systemic sclerosis treatment

Systemic sclerosis (SSc) is a rare chronic autoimmune disease characterized by vasculopathy, dysregulation of innate and adaptive immune responses, and progressive fibrosis. SSc remains an orphan disease, with high morbity and mortality in SSc patients. The mesenchymal stromal cells (MSC) demonstrate in vitro and in vivo pro-angiogenic, immuno-suppressive, and anti-fibrotic properties and appear as a promising stem cell therapy type, that may target the key pathological features of SSc disease. This review aims to summarize acquired knowledge in the field of :1) MSC definition and in vitro and in vivo functional properties, which vary according to the donor type (allogeneic or autologous), the tissue sources (bone marrow, adipose tissue or umbilical cord) or inflammatory micro-environment in the recipient; 2) preclinical studies in various SSc animal models , which showed reduction in skin and lung fibrosis after MSC infusion; 3) first clinical trials in human, with safety and early efficacy results reported in SSc patients or currently tested in several ongoing clinical trials.

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.

[From fibrogenesis towards fibrosis: Pathophysiological mechanisms and clinical presentations]

Fibrogenesis is a universal and ubiquitous process associated with tissue healing. The impairment of tissue homeostasis resulting from the deregulation of numerous cellular actors, under the effect of specific cytokine and pro-oxidative environments can lead to extensive tissue fibrosis, organ dysfunction and significant morbidity and mortality. This situation is frequent in internal medicine, since fibrosis is associated with most organ insufficiencies (i.e. cardiac, renal, or hepatic chronic failures), but also with cancer, a condition with common pathophysiological mechanisms. Finally, fibrosis is a hallmark of numerous systemic autoimmune diseases such as connective tissue disorders (in particular systemic sclerosis), vasculitides, granulomatoses, histiocytoses, and IgG4-associated disease. Although the process leading to tissue fibrosis may be in part irreversible, new pharmacological approaches or cell therapies bring hope in the field of fibrotic conditions.

A Comparison of Phenotypic and Functional Properties of Mesenchymal Stromal Cells and Multipotent Adult Progenitor Cells

Both Multipotent Adult Progenitor Cells and Mesenchymal Stromal Cells are bone-marrow derived, non-haematopoietic adherent cells, that are well-known for having immunomodulatory and pro-angiogenic properties, whilst being relatively non-immunogenic. However, they are phenotypically and functionally distinct cell types, which has implications for their efficacy in different settings. In this review we compare the phenotypic and functional properties of these two cell types, to help in determining which would be the superior cell type for different applications.

iNOS Activity Is Required for the Therapeutic Effect of Mesenchymal Stem Cells in Experimental Systemic Sclerosis

Objectives: Fibrosis is a hallmark of systemic sclerosis (SSc), an intractable disease where innovative strategies are still being sought. Among novel anti-fibrotic approaches, mesenchymal stromal/stem cell (MSC)-based therapy appears promising. Previously, we reported anti-fibrotic effects of MSC in an experimental model of SSc, through various mechanisms (tissue remodeling, immunomodulation, anti-oxidant defense). Since immunomodulation is a pivotal mechanism for MSC therapeutic effects, we investigated the specific role of critical molecules associated with MSC immunosuppressive properties and hypothesized that MSC defective for these molecules would be less effective in reducing fibrosis in SSc.

Methods: SSc was induced by 6-week daily intradermal injections of hypochlorite (HOCl) in mice. MSC were isolated from the bone marrow of wild type mice (WT) or mice knockout for IL1RA, IL6, or iNOS (IL1RA^−/−, IL6^−/−, or iNOS^−/− MSC, respectively). Treated-mice received 2.5 × 10⁵ MSC intravenous infusion at d21. Skin thickness, histological and biological parameters were evaluated in skin and blood at d42.

Results: IL1RA^−/− and IL6^−/− MSC exerted similar anti-fibrotic properties as WT MSC, with a reduction of skin thickness together with less collagen deposition. Conversely, iNOS^−/− MSC did not exert anti-fibrotic functions as shown by a similar skin thickness progression as non-treated HOCl-SSc mice. Compared with WT MSC, iNOS^−/− MSC kept some immunosuppressive and tissue remodeling properties, but lost their capacity to reduce oxidative stress in HOCl-SSc mice.

Conclusion: Our study highlights the crucial role of iNOS, whose activity is required for the anti-fibrotic properties of MSC in experimental SSc, with a special emphasis on NO-related anti-oxidant functions.