Improved motor function in dko mice by intravenous transplantation of bone marrow-derived mesenchymal stromal cells

Two-dimensional speckle tracking echocardiography demonstrates improved myocardial function after intravenous infusion of bone marrow mesenchymal stem in the X-Linked muscular dystrophy mice

Background

Bone marrow mesenchymal stem cells (BMSCs) are commonly used in regenerative medicine. However, it is not clear whether transplantation of BMSCs can improve cardiac function of the X-Linked Muscular Dystrophy Mice (mdx) and how to detect it. We aimed to investigate the role of speckle tracking echocardiography (STE) in detecting cardiac function of the BMSCs-transplanted mdx in comparison with the untreated mdx.

Methods

The experimental mice were divided into the BMSCs-transplanted mdx, untreated mdx, and control mice groups (n = 6 per group). The BMSCs were transplanted via tail vein injections into a subset of mdx at 20 weeks of age. After four weeks, the cardiac functional parameters of all the mice in the 3 groups were analyzed by echocardiography. Then, all the mice were sacrificed, and the cardiac tissues were harvested and analyzed by immunofluorescence. The serum biochemical parameters were also analyzed to determine the beneficial effects of BMSCs transplantation.

Results

Traditional echocardiography parameters did not show statistically significant differences after BMSCs transplantation for the three groups of mice. In comparison with the control group, mdx showed significantly lower left ventricular (LV) STE parameters in both the long-axis and short-axis LV images (P < 0.05). However, BMSCs-transplanted mdx showed improvements in several STE parameters including significant increases in a few STE parameters (P < 0.05). Immunofluorescence staining of the myocardium tissues showed statistically significant differences between the mdx and the control mice (P < 0.05), and the mdx transplanted with BMSCs demonstrated significantly improvement compared with the untreated mdx (P < 0.05).

Conclusion

This study demonstrated that the early reduction in the LV systolic and diastolic function in the mdx were accurately detected by STE. Furthermore, our study demonstrated that the transplantation of BMSCs significantly improved myocardial function in the mdx.

In utero transplantation of myoblasts and adipose-derived mesenchymal stem cells to murine models of Duchenne muscular dystrophy does not lead to engraftment and frequently results in fetal death

Introduction

Duchenne muscular dystrophy (DMD) is a progressive disease that leads to damage of muscle and myocardium due to genetic abnormalities in the dystrophin gene. In utero cell transplantation that might facilitate allogenic transplantation is worth considering to treat this disease.

Methods

We performed allogeneic in utero transplantation of GFP-positive myoblasts and adipose-derived mesenchymal stem cells into murine DMD model animals. The transplantation route in this study was fetal intraperitoneal transplantation and transplacental transplantation. Transplanted animals were examined at 4-weeks old by immunofluorescence staining and RT-qPCR.

Results

No GFP-positive cells were found by immunofluorescence staining of skeletal muscle and no GFP mRNA was detected by RT-qPCR in any animal, transplantation method and cell type. Compared with previous reports, myoblast transplantation exhibited an equivalent mortality rate, but adipose-derived stem cell (ASC) transplantation produced a higher mortality rate.

Conclusions

In utero transplantation of myoblasts or ASCs to murine models of DMD does not lead to engraftment and, in ASC transplantation primarily, frequently results in fetal death.

The Efficacy of Naïve versus Modified Mesenchymal Stem Cells in Improving Muscle Function in Duchenne Muscular Dystrophy: A Systematic Review

As one of the most common genetic conditions, Duchenne muscular dystrophy (DMD) is a fatal disease caused by a recessive mutation resulting in muscle weakness in both voluntary and involuntary muscles and, eventually, in death because of cardiovascular failure. Currently, there is no pharmacologically curative treatment of DMD, but there is evidence supporting that mesenchymal stem cells (MSCs) are a novel solution for treating DMD. This systematic review focused on elucidating the therapeutic efficacy of MSCs on the DMD in vivo model. A key issue of previous studies was the material-choice, naïve MSCs or modified MSCs; modified MSCs are activated by culture methods or genetic modification. In summary, MSCs seem to improve pulmonary and cardiac functions and thereby improve survival regardless of them being naïve or modified. The improved function of distal skeletal muscles was observed only with primed MSCs treatment but not naïve MSCs. While MSCs can provide significant benefits to DMD mouse models, there is little to no data on the results in human patients. Due to the limited number of human studies, the differences in study design, and the insufficient understanding of mechanisms of action, more rigorous comparative trials are needed to elucidate which types of MSCs and modifications have optimal therapeutic potential.

Mesenchymal Stromal Cells and Their Secretome: New Therapeutic Perspectives for Skeletal Muscle Regeneration

Mesenchymal stromal cells (MSCs) are multipotent cells found in different tissues: bone marrow, peripheral blood, adipose tissues, skeletal muscle, perinatal tissues, and dental pulp. MSCs are able to self-renew and to differentiate into multiple lineages, and they have been extensively used for cell therapy mostly owing to their anti-fibrotic and immunoregulatory properties that have been suggested to be at the basis for their regenerative capability. MSCs exert their effects by releasing a variety of biologically active molecules such as growth factors, chemokines, and cytokines, either as soluble proteins or enclosed in extracellular vesicles (EVs). Analyses of MSC-derived secretome and in particular studies on EVs are attracting great attention from a medical point of view due to their ability to mimic all the therapeutic effects produced by the MSCs (i.e., endogenous tissue repair and regulation of the immune system). MSC-EVs could be advantageous compared with the parental cells because of their specific cargo containing mRNAs, miRNAs, and proteins that can be biologically transferred to recipient cells. MSC-EV storage, transfer, and production are easier; and their administration is also safer than MSC therapy. The skeletal muscle is a very adaptive tissue, but its regenerative potential is altered during acute and chronic conditions. Recent works demonstrate that both MSCs and their secretome are able to help myofiber regeneration enhancing myogenesis and, interestingly, can be manipulated as a novel strategy for therapeutic interventions in muscular diseases like muscular dystrophies or atrophy. In particular, MSC-EVs represent promising candidates for cell free-based muscle regeneration. In this review, we aim to give a complete picture of the therapeutic properties and advantages of MSCs and their products (MSC-derived EVs and secreted factors) relevant for skeletal muscle regeneration in main muscular diseases.

Bone Marrow-Mesenchymal Stromal Cell Secretome as Conditioned Medium Relieves Experimental Skeletal Muscle Damage Induced by Ex Vivo Eccentric Contraction

Bone marrow-mesenchymal stem/stromal cells (MSCs) may offer promise for skeletal muscle repair/regeneration. Growing evidence suggests that the mechanisms underpinning the beneficial effects of such cells in muscle tissue reside in their ability to secrete bioactive molecules (secretome) with multiple actions. Hence, we examined the effects of MSC secretome as conditioned medium (MSC-CM) on ex vivo murine extensor digitorum longus muscle injured by forced eccentric contraction (EC). By combining morphological (light and confocal laser scanning microscopies) and electrophysiological analyses we demonstrated the capability of MSC-CM to attenuate EC-induced tissue structural damages and sarcolemnic functional properties’ modifications. MSC-CM was effective in protecting myofibers from apoptosis, as suggested by a reduced expression of pro-apoptotic markers, cytochrome c and activated caspase-3, along with an increase in the expression of pro-survival AKT factor. Notably, MSC-CM also reduced the EC-induced tissue redistribution and extension of telocytes/CD34⁺ stromal cells, distinctive cells proposed to play a “nursing” role for the muscle resident myogenic satellite cells (SCs), regarded as the main players of regeneration. Moreover, it affected SC functionality likely contributing to replenishment of the SC reservoir. This study provides the necessary groundwork for further investigation of the effects of MSC secretome in the setting of skeletal muscle injury and regenerative medicine.

Activation of Wnt3a signaling promotes myogenic differentiation of mesenchymal stem cells in mdx mice

AIM

Duchenne muscular dystrophy (DMD) is an X-linked genetic muscular disorder with no effective treatment at present. Mesenchymal stem cell (MSC) transplantation has been used to treat DMD, but the efficiency is low. Our previous studies show that activation of Wnt3a signaling promotes myogenic differentiation of MSCs in vitro. Here we report an effective MSC transplantation therapy in mdx mice by activation of Wnt3a signaling.

METHODS

MSCs were isolated from mouse bone marrow, and pretreated with Wnt3a-conditioned medium (Wnt3a-CM), then transplanted into mdx mice. The recipient mice were euthanized at 4, 8, 12, 16 weeks after the transplantation, and muscle pathological changes were examined. The expression of dystrophin in muscle was detected using immunofluorescence staining, RT-PCR and Western blotting.

RESULTS

Sixteen weeks later, transplantation of Wnt3a-pretreated MSCs in mdx mice improved the characteristics of dystrophic muscles evidenced by significant reductions in centrally nucleated myofibers, the variability range of cross-sectional area (CSA) and the connective tissue area of myofibers. Furthermore, transplantation of Wnt3a-pretreated MSCs in mdx mice gradually and markedly increased the expression of dystrophin in muscle, and improved the efficiency of myogenic differentiation.

CONCLUSION

Transplantation of Wnt3a-pretreated MSCs in mdx mice results in long-term amelioration of the dystrophic phenotype and restores dystrophin expression in muscle. The results suggest that Wnt3a may be a promising candidate for the treatment of DMD.

In vitro and in vivo analysis of human fibroblast reprogramming and multipotency

Multipotent stem cells have potential therapeutic roles in the treatment of Duchenne muscular dystrophy (DMD). However, the limited access to stem cell sources restricts their clinical application. To address this issue, we established a simple in vitro epigenetic reprogramming technique in which skin fibroblasts are induced to dedifferentiate into multipotent cells. In this study, human fibroblasts were isolated from circumcised adult foreskin and were reprogrammed by co-culture for 72 h with fish oocyte extract (FOE) in serum-free medium. The cells were then observed and analyzed by immunofluorescence staining, flow cytometry and in vitro differentiation assays. Then FOE-treated human fibroblasts were transplanted by tail vein injection into irradiated mdx mice, an animal model of DMD. Two months after injection, the therapeutic effects of FOE-treated fibroblasts on mdx skeletal muscle were evaluated by serum creatine kinase (CK) activity measurements and by immunostaining and RT-PCR of human dystrophin expression. The results indicated that the reprogrammed fibroblasts expressed higher levels of the pluripotent antigen markers SSEA-4, Nanog and Oct-4, and were able to differentiate in vitro into adipogenic cells, osteoblastic cells, and myotube-like cells. Tail vein injection of FOE-treated fibroblasts into irradiated mdx mice slightly reduced serum CK activity and the percentage of centrally nucleated myofibers two months after cell transplantation. Furthermore, we confirmed human dystrophin protein and mRNA expression in mdx mouse skeletal muscle. These data demonstrated that FOE-treated fibroblasts were multipotent and could integrate into mdx mouse myofibers through the vasculature.

Mesenchymal stromal cell secreted sphingosine 1-phosphate (S1P) exerts a stimulatory effect on skeletal myoblast proliferation

Bone-marrow-derived mesenchymal stromal cells (MSCs) have the potential to significantly contribute to skeletal muscle healing through the secretion of paracrine factors that support proliferation and enhance participation of the endogenous muscle stem cells in the process of repair/regeneration. However, MSC-derived trophic molecules have been poorly characterized. The aim of this study was to investigate paracrine signaling effects of MSCs on skeletal myoblasts. It was found, using a biochemical and morphological approach that sphingosine 1-phosphate (S1P), a natural bioactive lipid exerting a broad range of muscle cell responses, is secreted by MSCs and represents an important factor by which these cells exert their stimulatory effects on C2C12 myoblast and satellite cell proliferation. Indeed, exposure to conditioned medium obtained from MSCs cultured in the presence of the selective sphingosine kinase inhibitor (iSK), blocked increased cell proliferation caused by the conditioned medium from untreated MSCs, and the addition of exogenous S1P in the conditioned medium from MSCs pre-treated with iSK further increased myoblast proliferation. Finally, we also demonstrated that the myoblast response to MSC-secreted vascular endothelial growth factor (VEGF) involves the release of S1P from C2C12 cells. Our data may have important implications in the optimization of cell-based strategies to promote skeletal muscle regeneration.

Improvement of contraction force in injured skeletal muscle after autologous mesenchymal stroma cell transplantation is accompanied by slow to fast fiber type shift

BACKGROUND

Skeletal muscle trauma leads to severe functional deficits, which cannot be addressed by current treatment options. Previous investigation could show the efficacy of a local transplantation (TX) of mesenchymal stroma cells (MSCs) for the therapy of muscle injury. Underlying mechanisms remain to be elucidated. The aim of the present work was to characterize the fiber composition changes following MSC-TX after open crush injury.

METHODS

20 male SD rats received an open crush trauma of the left soleus muscle. 2.5 × 10(6) autologous MSCs were transplanted into the crushed soleus muscle of 10 animals 7 days after trauma (group 1, n = 10). Control animals received an injection of saline solution (group 2, n = 10). Histologic analysis of fibrosis, fiber type composition, and muscle force measurements were performed 28 days after trauma.

RESULTS

MSC-TX improved muscle force significantly (fast-twitch, treated: 0.76 (0.51-1.15), untreated: 0.45 (0.32-0.73); p = 0.01). Tetanic stimulation resulted in a significant increase of force development (treated: 0.63 (0.4-1.21), untreated: 0.34 (0.16-0.48); p = 0.04). Histological analyses showed no differences in the amount of fibrotic tissue (treated vs. untreated, p = 0.42). A shift towards fastMHC-positive fibers was observed following MSC-TX (treated vs. untreated; p = 0.01 (mm(2)) or 0.007 (%)).

CONCLUSION

This study demonstrated an effect of locally administered MSCs in the treatment of skeletal muscle injuries on a structural level. For the first time a fiber type shift towards fastMHC following MSC-TX after crush injury could be demonstrated and related to MSC-TX. These results might open the discussion of an alternative mode of action of MSCs in tissue regeneration.

Influence of mesenchymal stem cell transplantation on stereotypic behavior and dopamine levels in rats with Tourette syndrome

Context

Tourette syndrome (TS) is a heterogeneous neuropsychiatric disorder. Chronic motor and phonic tics are central symptoms in TS patients. For some patients, tics are intractable to any traditional treatment and cause lifelong impairment and life-threatening symptoms. New therapies should be developed to address symptoms and overt manifestations of TS. Transplantation of neurogenic stem cells might be a viable approach in TS treatment.

Objective

We used mesenchymal stem cell (MSC) transplantation to treat TS. We discuss the mechanism of action, as well as the efficiency of this approach, in treating TS.

Settings and Design

An autoimmune TS animal model was adopted in the present study. Forty-eight Wistar rats were randomly allocated to the control group and the 2 experimental groups, namely, TS rats+vehicle and TS rats+MSC. MSCs were co-cultured with 5-bromodeoxyuridine (BrdU) for 24 h for labeling prior to grafting.

Methods

Stereotypic behaviors were recorded at 1, 7, 14, and 28 days after transplantation. Dopamine (DA) content in the striatum of rats in the 3 groups was measured using a high-performance liquid chromatography column equipped with an electrochemical detector (HPLC-ECD) on day 28 after transplantation.

Statistical analysis

Statistical analysis was performed by repeated measurements analysis of variance to evaluate stereotypic behavior counts at different time points.

Results

TS rats exhibited higher stereotypic behavioral counts compared with the control group. One week after transplantation, TS rats with MSC grafts exhibited significantly decreased stereotypic behavior. Rats with MSC grafts also showed reduced levels of DA in the striatum when compared with TS rats, which were exposed only to the vehicle.

Conclusions

Intrastriatal transplantation of MSCs can provide relief from the stereotypic behavior of TS. Our results indicate that this approach may have potential for developing therapies against TS. The mechanism(s) of the observed effect may be related to the suppression of DA system by decreasing the content of DA in TS rats.

Trophic actions of bone marrow-derived mesenchymal stromal cells for muscle repair/regeneration

Bone marrow-derived mesenchymal stromal cells (BM-MSCs) represent the leading candidate cell in tissue engineering and regenerative medicine. These cells can be easily isolated, expanded in vitro and are capable of providing significant functional benefits after implantation in the damaged muscle tissues. Despite their plasticity, the participation of BM-MSCs to new muscle fiber formation is controversial; in fact, emerging evidence indicates that their therapeutic effects occur without signs of long-term tissue engraftment and involve the paracrine secretion of cytokines and growth factors with multiple effects on the injured tissue, including modulation of inflammation and immune reaction, positive extracellular matrix (ECM) remodeling, angiogenesis and protection from apoptosis. Recently, a new role for BM-MSCs in the stimulation of muscle progenitor cells proliferation has been demonstrated, suggesting the potential ability of these cells to influence the fate of local stem cells and augment the endogenous mechanisms of repair/regeneration in the damaged tissues.

Cell-matrix interactions in muscle disease

The extracellular matrix (ECM) provides a solid scaffold and signals to cells through ECM receptors. The cell-matrix interactions are crucial for normal biological processes and when disrupted they may lead to pathological processes. In particular, the biological importance of ECM-cell membrane-cytoskeleton interactions in skeletal muscle is accentuated by the number of inherited muscle diseases caused by mutations in proteins conferring these interactions. In this review we introduce laminins, collagens, dystroglycan, integrins, dystrophin and sarcoglycans. Mutations in corresponding genes cause various forms of muscular dystrophy. The muscle disorders are presented as well as advances toward the development of treatment.