Human mesenchymal stem cells abrogate experimental allergic encephalomyelitis after intraperitoneal injection, and with sparse CNS infiltration

MSC-Based Cell Therapy in Neurological Diseases: A Concise Review of the Literature in Pre-Clinical and Clinical Research

Mesenchymal stem cells (MSCs) are multipotent stromal cells with the ability to self-renew and multi-directional differentiation potential. Exogenously administered MSCs can migrate to damaged tissue sites and participate in the repair of damaged tissues. A large number of pre-clinical studies and clinical trials have demonstrated that MSCs have the potential to treat the abnormalities of congenital nervous system and neurodegenerative diseases. Therefore, MSCs hold great promise in the treatment of neurological diseases. Here, we summarize and highlight current progress in the understanding of the underlying mechanisms and strategies of MSC application in neurological diseases.

Cell replacement therapy with stem cells in multiple sclerosis, a systematic review

Multiple sclerosis (MS) is a chronic inflammatory, autoimmune, and neurodegenerative disease of the central nervous system (CNS), characterized by demyelination and axonal loss. It is induced by attack of autoreactive lymphocytes on the myelin sheath and endogenous remyelination failure, eventually leading to accumulation of neurological disability. Disease-modifying agents can successfully address inflammatory relapses, but have low efficacy in progressive forms of MS, and cannot stop the progressive neurodegenerative process. Thus, the stem cell replacement therapy approach, which aims to overcome CNS cell loss and remyelination failure, is considered a promising alternative treatment. Although the mechanisms behind the beneficial effects of stem cell transplantation are not yet fully understood, neurotrophic support, immunomodulation, and cell replacement appear to play an important role, leading to a multifaceted fight against the pathology of the disease. The present systematic review is focusing on the efficacy of stem cells to migrate at the lesion sites of the CNS and develop functional oligodendrocytes remyelinating axons. While most studies confirm the improvement of neurological deficits after the administration of different stem cell types, many critical issues need to be clarified before they can be efficiently introduced into clinical practice.

Intravenous transplantation of bone marrow-derived mesenchymal stromal cells in patients with multiple sclerosis, a phase I/IIa, double blind, randomized controlled study

Multiple sclerosis (MS) is a progressive, demyelinating neurodegenerative disease of the central nervous system. MS is immune-mediated and leads to disability especially in young adults. Even though 18 MS therapy drugs were approved, they slightly inhibit disease progression and do not induce regeneration and repair in the nervous system. Mesenchymal stromal cells (MSCs) have emerged as a new therapeutic modality in regenerative medicine and tissue engineering due to their immunomodulation and bio regenerative properties. We have designed a randomized, controlled clinical trial to assess safety and possible efficacy of MSC application in MS patients. Twenty-one MS patients were enrolled. Patients were allocated in two distinct groups: treatment group, which received systemic transplantation of autologous bone marrow-derived MSCs, and control group, which received placebo at the first injections. Patients in control group received MSCs at the second injection while the treatment group received placebo. All the patients were followed for 18 months. Follow-ups included regular visits, laboratory evaluation, and imaging analysis. Control patients received MSCs six month after treatment group. No severe immediate or late adverse events were observed in both groups after interventions. We did not find any significant differences in the rate of relapses, Expanded Disability Status Scale (EDSS) score, cognitive condition, Magnetic Resonance Imaging (MRI) findings, or any biomarkers of cerebrospinal fluid between the two groups and in each group before and after cell infusion. Transplantation of autologous bone marrow-derived mesenchymal stromal cells is safe and feasible. The efficacy of transplantation of these cells should be evaluated through designing randomized clinical trials with larger sample sizes, different administration routes, other cell types (allogeneic adipose derived MSCs, allogeneic Wharton's jelly derived MSCs …), repeated injections, and longer follow-up periods.

Stem-Cell-Based Therapy: The Celestial Weapon against Neurological Disorders

Stem cells are a versatile source for cell therapy. Their use is particularly significant for the treatment of neurological disorders for which no definitive conventional medical treatment is available. Neurological disorders are of diverse etiology and pathogenesis. Alzheimer's disease (AD) is caused by abnormal protein deposits, leading to progressive dementia. Parkinson's disease (PD) is due to the specific degeneration of the dopaminergic neurons causing motor and sensory impairment. Huntington's disease (HD) includes a transmittable gene mutation, and any treatment should involve gene modulation of the transplanted cells. Multiple sclerosis (MS) is an autoimmune disorder affecting multiple neurons sporadically but induces progressive neuronal dysfunction. Amyotrophic lateral sclerosis (ALS) impacts upper and lower motor neurons, leading to progressive muscle degeneration. This shows the need to try to tailor different types of cells to repair the specific defect characteristic of each disease. In recent years, several types of stem cells were used in different animal models, including transgenic animals of various neurologic disorders. Based on some of the successful animal studies, some clinical trials were designed and approved. Some studies were successful, others were terminated and, still, a few are ongoing. In this manuscript, we aim to review the current information on both the experimental and clinical trials of stem cell therapy in neurological disorders of various disease mechanisms. The different types of cells used, their mode of transplantation and the molecular and physiologic effects are discussed. Recommendations for future use and hopes are highlighted.

New idea to promote the clinical applications of stem cells or their extracellular vesicles in central nervous system disorders: combining with intranasal delivery

The clinical translation of stem cells and their extracellular vesicles (EVs)-based therapy for central nervous system (CNS) diseases is booming. Nevertheless, the insufficient CNS delivery and retention together with the invasiveness of current administration routes prevent stem cells or EVs from fully exerting their clinical therapeutic potential. Intranasal (IN) delivery is a possible strategy to solve problems as IN route could circumvent the brain‒blood barrier non-invasively and fit repeated dosage regimens. Herein, we gave an overview of studies and clinical trials involved with IN route and discussed the possibility of employing IN delivery to solve problems in stem cells or EVs-based therapy. We reviewed relevant researches that combining stem cells or EVs-based therapy with IN administration and analyzed benefits brought by IN route. Finally, we proposed possible suggestions to facilitate the development of IN delivery of stem cells or EVs.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

Mesenchymal stem cells as a treatment for multiple sclerosis: a focus on experimental animal studies

Multiple sclerosis (MS) is a progressive and debilitating neurological condition in which the immune system abnormally attacks the myelin sheath insulating the nerves. Mesenchymal stem cells (MSCs) are found in most adult tissues and play a significant systemic role in self-repair. MSCs have promising therapeutic effects in many diseases, such as autoimmune diseases, including MS. MSCs have been tested in MS animal models, such as experimental autoimmune encephalomyelitis. Other studies have combined other agents with MSCs, genetically modified MSCs, or used culture medium from MSCs. In this review, we will summarize these studies and compare the main factors in each study, such as the source of MSCs, the type of animal model, the route of injection, the number of injected cells, and the mechanism of action.

Delayed Double Treatment with Adult-Sourced Adipose-Derived Mesenchymal Stem Cells Increases Striatal Medium-Spiny Neuronal Number, Decreases Striatal Microglial Number, and Has No Subventricular Proliferative Effect, after Acute Neonatal Hypoxia-Ischemia in Male Rats

Perinatal hypoxia-ischemia (HI) is a major cause of striatal injury. Delayed post-treatment with adult-sourced bone marrow-derived mesenchymal stem cells (BMSCs) increased the absolute number of striatal medium-spiny neurons (MSNs) following perinatal HI-induced brain injury. Yet extraction of BMSCs is more invasive and difficult compared to extraction of adipose-derived mesenchymal stem cells (AD-MSCs), which are easily sourced from subcutaneous tissue. Adult-sourced AD-MSCs are also superior to BMSCs in the treatment of adult ischemic stroke. Therefore, we investigated whether delayed post-treatment with adult-sourced AD-MSCs increased the absolute number of striatal MSNs following perinatal HI-induced brain injury. This included investigation of the location of injected AD-MSCs within the brain, which were widespread in the dorsolateral subventricular zone (dlSVZ) at 1 day after their injection. Cells extracted from adult rat tissue were verified to be stem cells by their adherence to tissue culture plastic and their expression of specific ‘cluster of differentiation’ (CD) markers. They were verified to be AD-MSCs by their ability to differentiate into adipocytes and osteocytes in vitro. Postnatal day (PN) 7/8, male Sprague-Dawley rats were exposed to either HI right-sided brain injury or no HI injury. The HI rats were either untreated (HI + Diluent), single stem cell-treated (HI + MSCs×1), or double stem cell-treated (HI + MSCs×2). Control rats that were matched-for-weight and litter had no HI injury and were treated with diluent (Uninjured + Diluent). Treatment with AD-MSCs or diluent occurred either 7 days, or 7 and 9 days, after HI. There was a significant increase in the absolute number of striatal dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32)-positive MSNs in the double stem cell-treated (HI + MSCs×2) group and the normal control group compared to the HI + Diluent group at PN21. We therefore investigated two potential mechanisms for this effect of double-treatment with AD-MSCs. Specifically, did AD-MSCs: (i) increase the proliferation of cells within the dlSVZ, and (ii) decrease the microglial response in the dlSVZ and striatum? It was found that a primary repair mechanism triggered by double treatment with AD-MSCs involved significantly decreased striatal inflammation. The results may lead to the development of clinically effective and less invasive stem cell therapies for neonatal HI brain injury.

Effects of mesenchymal stem cells transplantation on multiple sclerosis patients

Multiple Sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system (CNS) with symptoms such as neuroinflammation and axonal degeneration. Existing drugs help reduce inflammatory conditions and protect CNS from demyelination and axonal damage; however, these drugs are unable to enhance axonal repair and remyelination. In this regard, cell therapy is considered as a promising regenerative approach to MS treatment. High immunomodulatory capacity, neuro-differentiation and neuroprotection properties have made Mesenchymal Stem Cells (MSCs) particularly useful for regenerative medicine. There are scant studies on the role of MSCs in patients suffering from MS. The low number of MS patients and the lack of control groups in these studies may explain the lack of beneficial effects of MSC transplantation in cell therapies. In this review, we evaluated the beneficial effects of MSC transplantation in clinical studies in terms of immunomodulatory, remyelinating and neuroprotecting properties of MSCs.

Application of Mesenchymal Stem Cells in Inflammatory and Fibrotic Diseases

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated from various tissues in the adult body. MSCs should be characterized by three criteria for regenerative medicine. MSCs must (1) adhere to plastic surfaces, (2) express specific surface antigens, and (3) differentiate into mesodermal lineages, including chondrocytes, osteoblasts, and adipocytes, in vitro. Interestingly, MSCs have immunomodulatory features and secrete trophic factors and immune receptors that regulate the microenvironment in host tissue. These specific and unique therapeutic properties make MSCs ideal as therapeutic agents in vivo. Specifically, pre-clinical and clinical investigators generated inflammatory and fibrotic diseases models, and then transplantation of MSCs into diseases models for therapeutic effects investigation. In this review, we characterize MSCs from various tissues and describe their applications for treating various inflammation and fibrotic diseases.

Mesenchymal stem cells in experimental autoimmune encephalomyelitis model of multiple sclerosis: A systematic review and meta-analysis

BACKGROUND/AIMS

Mesenchymal stem cells (MSCs) transplantation has been considered a possible therapeutic method for Multiple Sclerosis (MS). However, no quantitative data synthesis of MSCs therapy for MS exists. We conducted a systematic review and meta-analysis to evaluate the effects of MSCs in experimental autoimmune encephalomyelitis (EAE) animal model of MS.

METHODS

We identified eligible studies published from January 1980 to January 2017 by searching four electronic databases (PubMed, MEDLINE, Embase and Web of Science). The outcome was the effects of MSCs on clinical performance evaluated by the EAE clinical score.

RESULTS

36 preclinical studies including 675 animals in MSCs treatment group, and 693 animals in control group were included in this meta-analysis. We found that MSCs transplantation significantly ameliorated the symptoms and delayed the disease progression (SMD = -1.25, 95% CI: -1.45 to -1.05, P < 0.001). However, no significant differences in effect sizes were unveiled relative to clinical score standard (P = 0.35), type of MSCs (P = 0.35), source of MSCs (P = 0.06), MSCs dose (P = 0.44), delivery methods (P = 0.31) and follow up period (P = 0.73).

CONCLUSIONS

The current study showed that MSCs transplantation could ameliorate clinical performance in EAE animal model of MS. These findings support the further studies translate MSCs to treat MS in humans.

The effects of transplanted mesenchymal stem cells treated with 17-b estradiol on experimental autoimmune encephalomyelitis

The present study was conducted aimed at exploring the modulatory effects of 17-b estradiol (17-bED) on mesenchymal stem cells (MSCs) in the EAE (experimental autoimmune encephalomyelitis) animal model of multiple sclerosis (MS). Following the isolation of bone marrow-derived MSCs from the bilateral femurs and tibias of the male Wistar rats, the cells were harvested and cultured in the presence of 100 nM 17-bED for 24 h. EAE was induced in male Wistar rats (8-12 weeks old) using guinea pig spinal cord homogenate, in combination with the complete Freund's adjuvant. The MSC therapy was triggered when all of the animals obtained a disability score. The symptoms were monitored on a daily basis throughout the study until the rats were euthanized. The mRNA expression of cytokines, including IL-17, IFN-γ, TNF-α, IL-10, IL-4, and TGF-β together with MMP8 and MMP9 as the family members of matrix metalloproteinases (MMPs) in the brain and spinal cord tissues were examined using real-time PCR. The levels of splenocytes-originated IL-10 and IFN-γ cytokines were also measured by ELISA. The MTT-based research findings showed that the infiltration of lymphocytes into the spleen decreased considerably. It was also observed that the mRNA expression of proinflammatory cytokines decreased significantly, while the mRNA levels of anti-inflammatory cytokines increased remarkably. It was also found that the mRNA levels of the examined matrix metalloproteinases (MMP8 and MMP9) were downregulated significantly. The findings of the present study indicated that the administration of 17-bED enhanced the efficacy of MSCs transplantation and modulated immune responses relatively in the EAE model, via the regulation of either pro- or anti-inflammatory cytokines and matrix metalloproteinases.

Human ES-derived MSCs correct TNF-α-mediated alterations in a blood-brain barrier model

Background

Immune cell trafficking into the CNS is considered to contribute to pathogenesis in MS and its animal model, EAE. Disruption of the blood–brain barrier (BBB) is a hallmark of these pathologies and a potential target of therapeutics. Human embryonic stem cell-derived mesenchymal stem/stromal cells (hES-MSCs) have shown superior therapeutic efficacy, compared to bone marrow-derived MSCs, in reducing clinical symptoms and neuropathology of EAE. However, it has not yet been reported whether hES-MSCs inhibit and/or repair the BBB damage associated with neuroinflammation that accompanies EAE.

Methods

BMECs were cultured on Transwell inserts as a BBB model for all the experiments. Disruption of BBB models was induced by TNF-α, a pro-inflammatory cytokine that is a hallmark of acute and chronic neuroinflammation.

Results

Results indicated that hES-MSCs reversed the TNF-α-induced changes in tight junction proteins, permeability, transendothelial electrical resistance, and expression of adhesion molecules, especially when these cells were placed in direct contact with BMEC.

Conclusions

hES-MSCs and/or products derived from them could potentially serve as novel therapeutics to repair BBB disturbances in MS.

Electronic supplementary material

The online version of this article (10.1186/s12987-019-0138-5) contains supplementary material, which is available to authorized users.

Stem Cell-Based Therapies for Multiple Sclerosis: Current Perspectives

Multiple sclerosis (MS) is an inflammatory and neurodegenerative autoimmune disease of the central nervous system (CNS). Disease-modifying therapies (DMT) targeting inflammation have been shown to reduce disease activity in patients with relapsing–remitting MS (RRMS). The current therapeutic challenge is to find an effective treatment to halt disease progression and reverse established neural damage. Stem cell-based therapies have emerged to address this dilemma. Several types of stem cells have been considered for clinical use, such as autologous hematopoietic (aHSC), mesenchymal (MSC), neuronal (NSC), human embryonic (hESC), and induced pluripotent (iPSC) stem cells. There is convincing evidence that immunoablation followed by hematopoietic therapy (aHSCT) has a high efficacy for suppressing inflammatory MS activity and improving neurological disability in patients with RRMS. In addition, MSC therapy may be a safe and tolerable treatment, but its clinical value is still under evaluation. Various studies have shown early promising results with other cellular therapies for CNS repair and decreasing inflammation. In this review, we discuss the current knowledge and limitations of different stem cell-based therapies for the treatment of patients with MS.

IFNβ enhances mesenchymal stromal (Stem) cells immunomodulatory function through STAT1-3 activation and mTOR-associated promotion of glucose metabolism

Administration of mesenchymal stem cells (MSC) ameliorate experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), at both clinical and neuropathological levels. The therapeutic properties of MSC in EAE are mainly mediated by the modulation of pathogenic immune response, but other neurotropic effects, including decreased demyelination and axonal loss as well as promotion of tissue repair, play also a role. Properly controlled phase II clinical trials to explore the potential of MSC transplantation as a treatment for MS are underway. Interferon beta (IFNβ) is an approved treatment for relapsing-remitting and secondary progressive MS. Here, we explored the possibility that IFNβ might influence the therapeutic potential of MSC, in view of possible synergistic effects as add-on therapy. IFNβ enhanced the immunomodulatory functions of MSC and induced the expression of secretory leukocyte protease inhibitor (Slpi) and hepatocyte growth factor (Hgf), two soluble mediators involved in immune and regenerative functions of MSC. At molecular level, IFNβ induced a rapid and transient phosphorylation of STAT1 and STAT3, the transcription factors responsible for Slpi and Hgf induction. Concomitantly, IFNβ dynamically affected the activity of mTOR, a key checkpoint in the control of metabolic pathways. Indeed, the impairment of mTOR activity observed early upon exposure to IFNβ, was followed by a long-lasting induction of mTOR signaling, that was associated with an increased glycolytic capacity in MSC. When induced to switch their energetic metabolism towards glycolysis, MSC showed an improved ability to control T-cell proliferation. These results suggest that modifications of MSC energetic metabolism induced by IFNβ may contribute to promote MSC immunomodulatory function and support a role for metabolic pathways in the therapeutic function of MSC. Altogether, these findings support the idea of a combined treatment for MS, in which the immunomodulatory and possibly regenerative activity of MSC could be enhanced by the administration of IFNβ.

Effect of Multiple Intraperitoneal Injections of Human Bone Marrow Mesenchymal Stem Cells on Cuprizone Model of Multiple Sclerosis

Background:

Bone marrow mesenchymal stem cells (BM-MSCs) elicit neuroprotective effects, and their repair ability has been investigated in different experimental models. We aimed to investigate the effect of multiple i.p. BM-MSCs injections in the cuprizone model of multiple sclerosis in mice.

Methods:

Adult male C57BL/6 mice (n = 40) were fed a regular diet or a diet containing cuprizone (0.2% w/w) for six weeks. Bone marrow samples were taken from patients with spinal cord injury. BM-MSCs (2 × 10⁶ in 1 milliliter medium) were administered intraperitoneally for two consecutive weeks at the end of the forth weeks of cuprizone administration. Animals (n = 12) were perfused with 10% paraformaldehyde at the end of sixth week. The brains were sectioned coronally in 6-8-μm thickness (-2.3 to 1.8 mm from bregma). The sections were stained by luxol fast blue-cresyl violet, and images were captured via a microscope. Demyelination ratio was estimated in corpus callosum in a blind manner. A quantitative real-time PCR was used to measure the myelin basic protein gene expression at sixth week.

Results:

Histologically, cuprizone induced demyelination in the corpus callosum. Demyelinated area was diminished in the corpus callosum of cell-administered group. Cuprizone could decrease myelin-binding protein mRNAs expression in corpus callosum, which was significantly recovered after BM-MSCs injections.

Conclusion:

Our data indicated a remyelination potency of multiple i.p. BM-MSCs in the cuprizone model of multiple sclerosis in mice.

Mechanisms of Immune Suppression Utilized by Canine Adipose and Bone Marrow-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) from rodents and humans have been shown to suppress T cells by distinct primary pathways, with nitric oxide (NO)-dependent pathways dominating in rodents and indoleamine 2,3-deoxygenase (IDO)-dependent pathways dominating in humans. However, the immune suppressive pathways utilized by canine MSC have not been thoroughly studied, nor have bone marrow-derived MSC (BM-MSC) and adipose-derived MSC (Ad-MSC) been directly compared for their immune modulatory potency or pathway utilization. Therefore, canine BM-MSC and Ad-MSC were generated in vitro and their potency in suppressing T cell proliferation and cytokine production was compared, and differential gene expression. Mechanisms of T cells suppression were also investigated for both MSC types. We found that BM-MSC and Ad-MSC were roughly equivalent in terms of their ability to suppress T cell activation. However, the two MSC types used both shared and distinct biochemical pathways to suppress T cell activation. Ad-MSC utilized TGF-β signaling pathways and adenosine signaling to suppress T cell activation, whereas BM-MSC used cyclooxygenase, TGF-β and adenosine signaling pathways to suppress T cell activation. These results indicate that canine MSC are distinct from human and rodent MSC terms of their immune suppressive pathways, relying primarily on cyclooxygenase and TGF-β pathways for T cell suppression, rather than on NO or IDO-mediated pathways.

Stem Cell Therapy in the Treatment of Rheumatic Diseases and Application in the Treatment of Systemic Lupus Erythematosus

Current systemic therapies help to improve the symptoms and quality of life for patients with severe life-threatening rheumatic diseases but provide no curative treatment. For the past two decades, preclinical and clinical studies of stem cell transplantation (SCT) have demonstrated tremendous therapeutic potential for patients with autoimmune rheumatic diseases. Herein, the current advances on stem cell therapies, both in animal models and clinical studies, are discussed, with particular attention on systemic lupus erythematosus (SLE). Despite extensive research and promising data, our knowledge on mechanisms of action for SCT, its administration route and timing, the optimal dose of cells, the cells’ fate and distribution in vivo, and the safety and efficacy of the treatments remains limited. Further research on stem cell biology is required to ensure that therapeutic safety and efficacy, as observed in animal models, can be successfully translated in clinical trials. Current understanding, limitations, and future directions for SCT with respect to rheumatic diseases are also discussed.

Modulation of host immune responses following non-hematopoietic stem cell transplantation: Translational implications in progressive multiple sclerosis

There exists an urgent need for effective treatments for those patients suffering from chronic/progressive multiple sclerosis (MS). Accordingly, it has become readily apparent that different classes of stem cell-based therapies must be explored at both the basic science and clinical levels. Herein, we provide an overview of the basic mechanisms underlying the pre-clinical benefits of exogenously delivered non-hematopoietic stem cells (nHSCs) in animal models of MS. Further, we highlight a number of early clinical trials in which nHSCs have been used to treat MS. Finally, we identify a series of challenges that must be met and ultimately overcome if such promising therapeutics are to be advanced from the bench to the bedside.

Intravenous hMSCs Ameliorate Acute Pancreatitis in Mice via Secretion of Tumor Necrosis Factor-α Stimulated Gene/Protein 6

The administration of mesenchymal stem cells/multipotent mesenchymal stromal cells (MSCs) to enhance tissue repair is currently undergoing clinical trials. Some studies, including our previous work, have also revealed the beneficial effect of MSCs in severe acute pancreatitis (SAP); however, their mechanisms or mode of action remain controversial. In this study, we demonstrated that intravenously (i.v.)-administered human MSCs (hMSCs) remarkably promoted recovery from experimental SAP without significant engraftment of hMSCs in the damaged pancreas. Interestingly, we found that i.v.-administered hMSCs with knockdown of TSG-6 expression lost most of their anti-inflammatory effects and thus could not significantly ameliorate SAP. As expected, the effects of hMSCs were also duplicated by i.v. infusion of recombinant TSG-6. Furthermore, our results showed that the increase of oxidative stress, activation of the NLRP3 inflammasome and NF-κB signaling in SAP was substantially inhibited following administration of hMSCs or TSG-6, which was dependent on the presence of CD-44 receptors in acinar cells. In conclusion, our study, for the first time, revealed that novel mechanisms are responsible for the immunomodulatory effect of i.v. hMSCs.

Placental Stromal Cell Therapy for Experimental Autoimmune Encephalomyelitis: The Role of Route of Cell Delivery

Multiple sclerosis (MS) is an immune‐mediated disease of the central nervous system (CNS) with no effective treatment available for the chronic‐progressive stage. Cell therapy is a promising therapeutic approach for attenuating the immune‐mediated CNS process. Isolated and expanded human placental stromal cells (hPSCs) possess potent immunomodulatory and trophic properties, making them a good candidate for MS therapy. We examined the potential of hPSC therapy in preventing the onset or attenuating the course of established disease in a murine MS model of myelin oligodendrocyte glycoprotein‐induced experimental autoimmune encephalomyelitis. We examined the feasibility of hPSC systemic delivery by intramuscular (i.m.) implantation rather than the commonly used intravenous injection, which is dose‐limiting and carries the risk of pulmonary obstruction. Our findings showed significant attenuation of the disease only when hPSCs were injected directly to the central nervous system. Intramuscular implanted hPSCs survived at the site of injection for at least 2 months and elicited extensive local immune responses. Intramuscular hPSC implantation before disease onset caused a delay in the appearance of clinical signs and reduced the severity of a relapse induced by repeated challenge with the autoantigen. Intramuscular implantation after disease onset did not affect its course. Thus, pathological analysis of CNS tissue did not show inhibition of neuroinflammation in i.m. hPSC‐implanted mice. Moreover, no apparent effect was seen on the proliferative response of peripheral lymph node cells in these animals. We conclude that to maximize their therapeutic potential in MS, hPSCs should be delivered directly to the affected CNS. Stem Cells Translational Medicine2017;6:1286–1294

Mesenchymal Stromal/Stem Cells Do Not Ameliorate Experimental Autoimmune Encephalomyelitis and Are Not Detectable in the Central Nervous System of Transplanted Mice

Mesenchymal stromal/stem cells (MSCs) constitute progenitor cells that can be isolated from different tissues. Based on their immunomodulatory and neuroprotective functions, MSC-based cell-therapy approaches have been suggested to antagonize inflammatory activity and neuronal damage associated with autoimmune disease of the central nervous system (CNS), for example, multiple sclerosis (MS). Intravenous MSC transplantation was reported to ameliorate experimental autoimmune encephalomyelitis (EAE), the murine model of MS, within days after transplantation. However, systemic distribution patterns and fate of MSCs after administration, especially their potential to migrate into inflammatory lesions within the CNS, remain to be elucidated. This question has of recent become particularly important, since therapeutic infusion of MSCs is now being tested in clinical trials with MS-affected patients. Here, we made use of the established EAE mouse model to investigate migration and therapeutic efficacy of murine bone marrow-derived MSCs. Applying a variety of techniques, including magnetic resonance imaging, immunohistochemistry, fluorescence in-situ hybridization, and quantitative polymerase chain reaction we found no evidence for immediate migration of infused MSC into the CNS of treated mice. Moreover, in contrast to other studies, transplanted MSCs did not ameliorate EAE. In conclusion, our data does not provide substantiation for a relevant migration of infused MSCs into the CNS of EAE mice supporting the hypothesis that potential therapeutic efficacy could be based on systemic effects. Evaluation of possible mechanisms underlying the observed discrepancies in MSC treatment outcomes between different EAE models demands further studies.

Human Mesenchymal Stem Cells Impact Th17 and Th1 Responses Through a Prostaglandin E2 and Myeloid-Dependent Mechanism

: Human mesenchymal stem cells (hMSCs) are being increasingly pursued as potential therapies for immune-mediated conditions, including multiple sclerosis. Although they can suppress human Th1 responses, they reportedly can reciprocally enhance human Th17 responses. Here, we investigated the mechanisms underlying the capacity of hMSCs to modulate human Th1 and Th17 responses. Human adult bone marrow-derived MSCs were isolated, and their purity and differentiation capacity were confirmed. Human venous peripheral blood mononuclear cells (PBMC) were activated, alone, together with hMSC, or in the presence of hMSC-derived supernatants (sups). Cytokine expression by CD4+ T-cell subsets (intracellular staining by fluorescence-activated cell sorting) and secreted cytokines (enzyme-linked immunosorbent assay) were then quantified. The contribution of prostaglandin E2 (PGE2) as well as of myeloid cells to the hMSC-mediated regulation of T-cell responses was investigated by selective depletion of PGE2 from the hMSC sups (anti-PGE2 beads) and by the selective removal of CD14+ cells from the PBMC (magnetic-activated cell sorting separation). Human MSC-secreted products could reciprocally induce interleukin-17 expression while decreasing interferon-γ expression by human CD4+ T cells, both in coculture and through soluble products. Pre-exposure of hMSCs to IL-1β accentuated their capacity to reciprocally regulate Th1 and Th17 responses. Human MSCs secreted high levels of PGE2, which correlated with their capacity to regulate the T-cell responses. Selective removal of PGE2 from the hMSC supernatants abrogated the impact of hMSC on the T cells. Selective removal of CD14+ cells from the PBMCs also limited the capacity of hMSC-secreted PGE2 to affect T-cell responses. Our discovery of a novel PGE2-dependent and myeloid cell-mediated mechanism by which human MSCs can reciprocally induce human Th17 while suppressing Th1 responses has implications for the use of, as well as monitoring of, MSCs as a potential therapeutic for patients with multiple sclerosis and other immune-mediated diseases.

SIGNIFICANCE

Although animal studies have generated a growing interest in the anti-inflammatory potential of mesenchymal stem cells (MSCs) for the treatment of autoimmune diseases, MSCs possess the capacity to both limit and promote immune responses. Yet relatively little is known about human-MSC modulation of human disease-implicated T-cell responses, or the mechanisms underlying such modulation. The current study reveals a novel prostaglandin E2-dependent and myeloid cell-mediated mechanism by which human MSCs can reciprocally regulate human Th17 and Th1 responses, with implications for the use of MSCs as a potential therapeutic for patients with multiple sclerosis and other immune-mediated diseases.

Intraventricular injections of mesenchymal stem cells activate endogenous functional remyelination in a chronic demyelinating murine model

Current treatments for demyelinating diseases are generally only capable of ameliorating the symptoms, with little to no effect in decreasing myelin loss nor promoting functional recovery. Mesenchymal stem cells (MSCs) have been shown by many researchers to be a potential therapeutic tool in treating various neurodegenerative diseases, including demyelinating disorders. However, in the majority of the cases, the effect was only observed locally, in the area surrounding the graft. Thus, in order to achieve general remyelination in various brain structures simultaneously, bone marrow-derived MSCs were transplanted into the lateral ventricles (LVs) of the cuprizone murine model. In this manner, the cells may secrete soluble factors into the cerebrospinal fluid (CSF) and boost the endogenous oligodendrogenic potential of the subventricular zone (SVZ). As a result, oligodendrocyte progenitor cells (OPCs) were recruited within the corpus callosum (CC) over time, correlating with an increased myelin content. Electrophysiological studies, together with electron microscopy (EM) analysis, indicated that the newly formed myelin correctly enveloped the demyelinated axons and increased signal transduction through the CC. Moreover, increased neural stem progenitor cell (NSPC) proliferation was observed in the SVZ, possibly due to the tropic factors released by the MSCs. In conclusion, the findings of this study revealed that intraventricular injections of MSCs is a feasible method to elicit a paracrine effect in the oligodendrogenic niche of the SVZ, which is prone to respond to the factors secreted into the CSF and therefore promoting oligodendrogenesis and functional remyelination.

Assessment of bone marrow-derived Cellular Therapy in progressive Multiple Sclerosis (ACTiMuS): study protocol for a randomised controlled trial

BACKGROUND

We have recently completed an evaluation of the safety and feasibility of intravenous delivery of autologous bone marrow in patients with progressive multiple sclerosis (MS). The possibility of repair was suggested by improvement in the neurophysiological secondary outcome measure seen in all participants. The current study will examine the efficacy of intravenous delivery of autologous marrow in progressive MS. Laboratory studies performed in parallel with the clinical trial will further investigate the biology of bone marrow-derived stem cell infusion in MS, including mechanisms underlying repair.

METHODS/DESIGN

A prospective, randomised, double-blind, placebo-controlled, stepped wedge design will be employed at a single centre (Bristol, UK). Eighty patients with progressive MS will be recruited; 60 will have secondary progressive disease (SPMS) but a subset (n = 20) will have primary progressive disease (PPMS). Participants will be randomised to either early or late (1 year) intravenous infusion of autologous, unfractionated bone marrow. The placebo intervention is infusion of autologous blood. The primary outcome measure is global evoked potential derived from multimodal evoked potentials. Secondary outcome measures include adverse event reporting, clinical (EDSS and MSFC) and self-assessment (MSIS-29) rating scales, optical coherence tomography (OCT) as well as brain and spine MRI. Participants will be followed up for a further year following the final intervention. Outcomes will be analysed on an intention-to-treat basis.

DISCUSSION

Assessment of bone marrow-derived Cellular Therapy in progressive Multiple Sclerosis (ACTiMuS) is the first randomised, placebo-controlled trial of non-myeloablative autologous bone marrow-derived stem cell therapy in MS. It will determine whether bone marrow cell therapy can, as was suggested by the phase I safety study, improve conduction in multiple central nervous system pathways affected in progressive MS. Furthermore, laboratory studies performed in parallel with the clinical trial will inform our understanding of the cellular pharmacodynamics of bone marrow infusion in MS patients and the mechanisms underlying cell therapy.

TRIAL REGISTRATION

ISRCTN27232902 Registration date 11/09/2012. NCT01815632 Registration date 19/03/2013.

Bottlenecks in the Efficient Use of Advanced Therapy Medicinal Products Based on Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) have been established as promising candidate sources of universal donor cells for cell therapy due to their contributions to tissue and organ homeostasis, repair, and support by self-renewal and multidifferentiation, as well as by their anti-inflammatory, antiproliferative, immunomodulatory, trophic, and proangiogenic properties. Various diseases have been treated by MSCs in animal models. Additionally, hundreds of clinical trials related to the potential benefits of MSCs are in progress. However, although all MSCs are considered suitable to exert these functions, dissimilarities have been found among MSCs derived from different tissues. The same levels of efficacy and desired outcomes have not always been achieved in the diverse studies that have been performed thus far. Moreover, autologous MSCs can be affected by the disease status of patients, compromising their use. Therefore, collecting information regarding the characteristics of MSCs obtained from different sources and the influence of the host (patient) medical conditions on MSCs is important for assuring the safety and efficacy of cell-based therapies. This review provides relevant information regarding factors to consider for the clinical application of MSCs.

Mesenchymal stem cells in the treatment of inflammatory and autoimmune diseases in experimental animal models

Multipotent mesenchymal stromal cells [also known as mesenchymal stem cells (MSCs)] are currently being studied as a cell-based treatment for inflammatory disorders. Experimental animal models of human immune-mediated diseases have been instrumental in establishing their immunosuppressive properties. In this review, we summarize recent studies examining the effectiveness of MSCs as immunotherapy in several widely-studied animal models, including type 1 diabetes, experimental autoimmune arthritis, experimental autoimmune encephalomyelitis, inflammatory bowel disease, graft-vs-host disease, and systemic lupus erythematosus. In addition, we discuss mechanisms identified by which MSCs mediate immune suppression in specific disease models, and potential sources of functional variability of MSCs between studies.

Delayed post-treatment with bone marrow-derived mesenchymal stem cells is neurorestorative of striatal medium-spiny projection neurons and improves motor function after neonatal rat hypoxia-ischemia

Perinatal hypoxia-ischemia is a major cause of striatal injury and may lead to cerebral palsy. This study investigated whether delayed administration of bone marrow-derived mesenchymal stem cells (MSCs), at one week after neonatal rat hypoxia-ischemia, was neurorestorative of striatal medium-spiny projection neurons and improved motor function. The effect of a subcutaneous injection of a high-dose, or a low-dose, of MSCs was investigated in stereological studies. Postnatal day (PN) 7 pups were subjected to hypoxia-ischemia. At PN14, pups received treatment with either MSCs or diluent. A subset of high-dose pups, and their diluent control pups, were also injected intraperitoneally with bromodeoxyuridine (BrdU), every 24h, on PN15, PN16 and PN17. This permitted tracking of the migration and survival of neuroblasts originating from the subventricular zone into the adjacent injured striatum. Pups were euthanized on PN21 and the absolute number of striatal medium-spiny projection neurons was measured after immunostaining for DARPP-32 (dopamine- and cAMP-regulated phosphoprotein-32), double immunostaining for BrdU and DARPP-32, and after cresyl violet staining alone. The absolute number of striatal immunostained calretinin interneurons was also measured. There was a statistically significant increase in the absolute number of DARPP-32-positive, BrdU/DARPP-32-positive, and cresyl violet-stained striatal medium-spiny projection neurons, and fewer striatal calretinin interneurons, in the high-dose mesenchymal stem cell (MSC) group compared to their diluent counterparts. A high-dose of MSCs restored the absolute number of these neurons to normal uninjured levels, when compared with previous stereological data on the absolute number of cresyl violet-stained striatal medium-spiny projection neurons in the normal uninjured brain. For the low-dose experiment, in which cresyl violet-stained striatal medium-spiny neurons alone were measured, there was a lower statistically significant increase in their absolute number in the MSC group compared to their diluent controls. Investigation of behavior in another cohort of animals showed that delayed administration of a high-dose of bone marrow-derived MSCs, at one week after neonatal rat hypoxia-ischemia, improved motor function on the cylinder test. Thus, delayed therapy with a high- or low-dose of adult MSCs, at one week after injury, is effective in restoring the loss of striatal medium-spiny projection neurons after neonatal rat hypoxia-ischemia and a high-dose of MSCs improved motor function.

Intranasal delivery of stem cells as therapy for central nervous system disease

Stem cells, upon entering the CNS, can preferentially migrate into disease foci, where they exert therapeutic effects that compensate for lost tissue, reconstructing damaged neuronal circuitry and establishing in the brain a new microenvironment suitable for cell survival. However, the route of stem cell delivery into the CNS remains a challenge: with systemic administration (e.g., intravenous injection), a fraction of cells may be trapped in other organs than the CNS, while direct CNS injections, e.g., intracerebroventricular or transcranial, are invasive. Intranasal (i.n.) delivery of stem cells, in contrast, can effectively bypass the blood-brain barrier, rapidly enter the CNS, and minimize systemic distribution. I.n. delivery of stem cells may therefore be a safe and non-invasive way of targeting the CNS and would thus be a promising therapeutic option for CNS disease. In this review we discuss the i.n. route for stem cell delivery into the CNS, and the perspectives of i.n. stem cell-based therapy in CNS disease.

Immunomodulatory characteristics of mesenchymal stem cells and their role in the treatment of multiple sclerosis

Multiple Sclerosis (MS) is a chronic inflammatory neurodegenerative disease of central nervous system (CNS). Although the main cause of MS is not clear, studies suggest that MS is an autoimmune disease which attacks myelin sheath of neurons. There are different therapeutic regimens for MS patients including interferon (IFN)-β, glatiramer acetate (GA), and natalizumab. However, such therapies are not quite effective and are associated with some side effects. So which, there is no complete therapeutic method for MS patients. Regarding the potent immunomodulatory effects of mesenchymal stem cells (MSCs) and their ameliorative effects in experimental autoimmune encephalopathy (EAE), it seems that MSCs may be a new therapeutic method in MS therapy. MSC transplantation is an approach to regulate the immune system in the region of CNS lesions. In this review, we have tried to discuss about the immunomodulatory properties of MSCs and their therapeutic mechanisms in MS patients.

Could cord blood cell therapy reduce preterm brain injury?

Major advances in neonatal care have led to significant improvements in survival rates for preterm infants, but this occurs at a cost, with a strong causal link between preterm birth and neurological deficits, including cerebral palsy (CP). Indeed, in high-income countries, up to 50% of children with CP were born preterm. The pathways that link preterm birth and brain injury are complex and multifactorial, but it is clear that preterm birth is strongly associated with damage to the white matter of the developing brain. Nearly 90% of preterm infants who later develop spastic CP have evidence of periventricular white matter injury. There are currently no treatments targeted at protecting the immature preterm brain. Umbilical cord blood (UCB) contains a diverse mix of stem and progenitor cells, and is a particularly promising source of cells for clinical applications, due to ethical and practical advantages over other potential therapeutic cell types. Recent studies have documented the potential benefits of UCB cells in reducing brain injury, particularly in rodent models of term neonatal hypoxia–ischemia. These studies indicate that UCB cells act via anti-inflammatory and immuno-modulatory effects, and release neurotrophic growth factors to support the damaged and surrounding brain tissue. The etiology of brain injury in preterm-born infants is less well understood than in term infants, but likely results from episodes of hypoperfusion, hypoxia–ischemia, and/or inflammation over a developmental period of white matter vulnerability. This review will explore current knowledge about the neuroprotective actions of UCB cells and their potential to ameliorate preterm brain injury through neonatal cell administration. We will also discuss the characteristics of UCB-derived from preterm and term infants for use in clinical applications.

Intranasal delivery of central nervous system-retargeted human mesenchymal stromal cells prolongs treatment efficacy of experimental autoimmune encephalomyelitis

Treatment with mesenchymal stromal cells (MSCs) is currently of interest for a number of diseases including multiple sclerosis. MSCs are known to target inflamed tissues, but in a therapeutic setting their systemic administration will lead to few cells reaching the brain. We hypothesized that MSCs may target the brain upon intranasal administration and persist in central nervous system (CNS) tissue if expressing a CNS-targeting receptor. To demonstrate proof of concept, MSCs were genetically engineered to express a myelin oligodendrocyte glycoprotein-specific receptor. Engineered MSCs retained their immunosuppressive capacity, infiltrated into the brain upon intranasal cell administration, and were able to significantly reduce disease symptoms of experimental autoimmune encephalomyelitis (EAE). Mice treated with CNS-targeting MSCs were resistant to further EAE induction whereas non-targeted MSCs did not give such persistent effects. Histological analysis revealed increased brain restoration in engineered MSC-treated mice. In conclusion, MSCs can be genetically engineered to target the brain and prolong therapeutic efficacy in an EAE model.

Comparative Study between Intravenous and Intraperitoneal Stem Cell Therapy in Amiodarone Induced Lung Injury in Rat

Background and Objectives:

The fibrosing form of lung injury (occupational, environmental, infective or drug induced) is associated with significant morbidity and mortality. Amiodarone (AM), often prescribed for control of arrhythmias is considered a potential cause. No effective treatment was confirmed, except lung transplantation. Intravenous (IV) stem cell therapy may produce pulmonary emboli or infarctions. Despite being commonly used in clinical practice, the intraperitoneal (IP.) route has been rarely used for cell delivery. The present study aimed at investigating and comparing the possible effect of IP stem cell therapy (SCT) on pulmonary toxicity versus the intravenous route in a rat model of amiodarone induced lung damage.

Methods and Results:

36 adult male albino rats were divided into 4 groups. Rats of AM group were given 30 mg/kg daily orally for 4 weeks. Rats of IV SCT group were injected with stem cells in the tail vein. Rats of IP SCT group received IP cell therapy. Histological, histochemical, immunohistochemical and morphometric studies were performed. Obstructed bronchioles, overdistended alveoli, reduced type I pneumocytes, increased thickness of alveolar septa and vessels wall besides increased area% of collagen fibers regressed in response to IV and IP SCT. The improvement was more obvious in IV group. The area% of Prussion blue +ve and CD105 +ve cells was significantly higher in IV group.

Conclusions:

Cord blood MSC therapy proved definite amelioration of lung injury ending in fibrosis. The effect of IP SCT was slightly inferior to that of IV SCT, which may be overwhelmed by repeated IP injection.

Human ESC-derived MSCs outperform bone marrow MSCs in the treatment of an EAE model of multiple sclerosis

Current therapies for multiple sclerosis (MS) are largely palliative, not curative. Mesenchymal stem cells (MSCs) harbor regenerative and immunosuppressive functions, indicating a potential therapy for MS, yet the variability and low potency of MSCs from adult sources hinder their therapeutic potential. MSCs derived from human embryonic stem cells (hES-MSCs) may be better suited for clinical treatment of MS because of their unlimited and stable supply. Here, we show that hES-MSCs significantly reduce clinical symptoms and prevent neuronal demyelination in a mouse experimental autoimmune encephalitis (EAE) model of MS, and that the EAE disease-modifying effect of hES-MSCs is significantly greater than that of human bone-marrow-derived MSCs (BM-MSCs). Our evidence also suggests that increased IL-6 expression by BM-MSCs contributes to the reduced anti-EAE therapeutic activity of these cells. A distinct ability to extravasate and migrate into inflamed CNS tissues may also be associated with the robust therapeutic effects of hES-MSCs on EAE.

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hES-MSCs show increased anti-EAE effects relative to adult human BM-MSCs

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hES-MSCs express fewer proinflammatory cytokines than BM-MSCs

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hES-MSCs enter the CNS more efficiently than BM-MSCs in EAE

Disease modification in multiple sclerosis: an update

Although there has been unequivocal progress in the development of treatments for multiple sclerosis over the last 20&emsp14;years, currently licensed treatments have demonstrated convincing effects on disease course only with reference to relapse frequency. This review summarises the progress made, highlights the indications for, and limitations of, current disease-modifying therapies and discusses some interventions currently in development.

Cell therapy for multiple sclerosis: an evolving concept with implications for other neurodegenerative diseases

Multiple sclerosis is a major cause of neurological disability, and particularly occurs in young adults. It is characterised by conspicuous patches of damage throughout the brain and spinal cord, with loss of myelin and myelinating cells (oligodendrocytes), and damage to neurons and axons. Multiple sclerosis is incurable, but stem-cell therapy might offer valuable therapeutic potential. Efforts to develop stem-cell therapies for multiple sclerosis have been conventionally built on the principle of direct implantation of cells to replace oligodendrocytes, and therefore to regenerate myelin. Recent progress in understanding of disease processes in multiple sclerosis include observations that spontaneous myelin repair is far more widespread and successful than was previously believed, that loss of axons and neurons is more closely associated with progressive disability than is myelin loss, and that damage occurs diffusely throughout the CNS in grey and white matter, not just in discrete, isolated patches or lesions. These findings have introduced new and serious challenges that stem-cell therapy needs to overcome; the practical challenges to achieve cell replacement alone are difficult enough, but, to be useful, cell therapy for multiple sclerosis must achieve substantially more than the replacement of lost oligodendrocytes. However, parallel advances in understanding of the reparative properties of stem cells--including their distinct immunomodulatory and neuroprotective properties, interactions with resident or tissue-based stem cells, cell fusion, and neurotrophin elaboration--offer renewed hope for development of cell-based therapies. Additionally, these advances suggest avenues for translation of this approach not only for multiple sclerosis, but also for other common neurological and neurodegenerative diseases.

Primary progressive multiple sclerosis: progress and challenges

Primary progressive multiple sclerosis (MS) has long been recognised as presenting great difficulties to our management of what is increasingly a treatable neurological disease. Here we review some basic and clinical aspects of primary progressive MS, and describe how the disorder in fact offers powerful insights and opportunities for better understanding multiple sclerosis, and from a practical perspective an invaluable clinical substrate for studying and treating progressive disability in MS. Difficult hurdles remain, however, and these too are reviewed.

Intravenous Administration of Human Umbilical Cord Mesenchymal Stem Cells Improves Cognitive Impairments and Reduces Amyloid-Beta Deposition in an AβPP/PS1 Transgenic Mouse Model

Alzheimer's disease (AD) is characterized by Amyloid-β (Aβ) deposition in senile plaques in specific areas of the brain and by intraneuronal p-tau accumulation in neurofibrillary tangles. Cumulative evidence supports that oxidative stress is an important factor in the pathogenesis of AD and contributes to Aβ generation. However, there is no effective treatment for AD. Human umbilical cord mesenchymal stem cells (HUMSCs) have potential therapeutic value for the treatment of neurological disease. However, the therapeutic impact of systemic administration of HUMSCs and their mechanism of action in AD have not yet been determined. Here, we found that intravenous infusion of HUMSCs significantly improved spatial learning and alleviated memory decline in an AβPP/PS1 mouse model of AD. HUMSC treatment also increased glutathione (GSH) activity and ratio of GSH to oxidative glutathione as well as superoxide dismutase activity, while decreasing malondialdehyde activity and protein carbonyl level, which suggests that HUMSC infusion alleviated oxidative stress in AβPP/PS1 mice. In addition, HUMSC infusion reduced β-secretase 1 and CTFβ, thus reducing Aβ deposition in mice. HUMSCs may have beneficial effects in the prevention and treatment of AD.

Administration of murine stromal vascular fraction ameliorates chronic experimental autoimmune encephalomyelitis

Administration of adipose-derived stromal/stem cells (ASCs) represents a promising therapeutic approach for autoimmune diseases since they have been shown to have immunomodulatory properties. The uncultured, nonexpanded counterpart of ASCs, the stromal vascular fraction (SVF), is composed of a heterogeneous mixture of cells. Although administration of ex vivo culture-expanded ASCs has been used to study immunomodulatory mechanisms in multiple models of autoimmune diseases, less is known about SVF-based therapy. The ability of murine SVF cells to treat myelin oligodendrocyte glycoprotein35-55-induced experimental autoimmune encephalitis (EAE) was compared with that of culture-expanded ASCs in C57Bl/6J mice. A total of 1 × 10(6) SVF cells or ASCs were administered intraperitoneally concomitantly with the induction of disease. The data indicate that intraperitoneal administration of ASCs significantly ameliorated the severity of disease course. They also demonstrate, for the first time, that the SVF effectively inhibited disease severity and was statistically more effective than ASCs. Both cell therapies also demonstrated a reduction in tissue damage, a decrease in inflammatory infiltrates, and a reduction in sera levels of interferon-γ and interleukin-12. Based on these data, SVF cells effectively inhibited EAE disease progression more than culture-expanded ASCs.

The stem cell secretome and its role in brain repair

Compelling evidence exists that non-haematopoietic stem cells, including mesenchymal (MSCs) and neural/progenitor stem cells (NPCs), exert a substantial beneficial and therapeutic effect after transplantation in experimental central nervous system (CNS) disease models through the secretion of immune modulatory or neurotrophic paracrine factors. This paracrine hypothesis has inspired an alternative outlook on the use of stem cells in regenerative neurology. In this paradigm, significant repair of the injured brain may be achieved by injecting the biologics secreted by stem cells (secretome), rather than implanting stem cells themselves for direct cell replacement. The stem cell secretome (SCS) includes cytokines, chemokines and growth factors, and has gained increasing attention in recent years because of its multiple implications for the repair, restoration or regeneration of injured tissues. Thanks to recent improvements in SCS profiling and manipulation, investigators are now inspired to harness the SCS as a novel alternative therapeutic option that might ensure more efficient outcomes than current stem cell-based therapies for CNS repair. This review discusses the most recent identification of MSC- and NPC-secreted factors, including those that are trafficked within extracellular membrane vesicles (EVs), and reflects on their potential effects on brain repair. It also examines some of the most convincing advances in molecular profiling that have enabled mapping of the SCS.

Towards clinical application of mesenchymal stem cells for treatment of neurological diseases of the central nervous system

The diagnosis of a neurological disease of the central nervous system (CNS) is often associated with the anticipation of an irreversible and untreatable disability. This is the case also of multiple sclerosis (MS) where approved treatments effectively modulate the autoimmune attack to myelin antigens, but poorly affect neurodegeneration and do not promote tissue repair. Thus, stem cell-based therapies are increasingly being considered a possible strategy for diseases of the CNS. Mesenchymal stem cells (MSC), the safety of which has been demonstrated in the last 20 years through clinical trials and case studies, are of particular interest in view not only of their neuroprotective, but also of their immunomodulatory properties. Here, we review the therapeutic features of MSC that make them relevant in the treatment of CNS illnesses and discuss the pioneer clinical experience with MSC-based therapy in neurological diseases.

Therapeutic potential of mesenchymal stem cells in regenerative medicine

Mesenchymal stem cells (MSCs) are stromal cells that have the ability to self-renew and also exhibit multilineage differentiation into both mesenchymal and nonmesenchymal lineages. The intrinsic properties of these cells make them an attractive candidate for clinical applications. MSCs are of keen interest because they can be isolated from a small aspirate of bone marrow or adipose tissues and can be easily expanded in vitro. Moreover, their ability to modulate immune responses makes them an even more attractive candidate for regenerative medicine as allogeneic transplant of these cells is feasible without a substantial risk of immune rejection. MSCs secrete various immunomodulatory molecules which provide a regenerative microenvironment for a variety of injured tissues or organ to limit the damage and to increase self-regulated tissue regeneration. Autologous/allogeneic MSCs delivered via the bloodstream augment the titers of MSCs that are drawn to sites of tissue injury and can accelerate the tissue repair process. MSCs are currently being tested for their potential use in cell and gene therapy for a number of human debilitating diseases and genetic disorders. This paper summarizes the current clinical and nonclinical data for the use of MSCs in tissue repair and potential therapeutic role in various diseases.

The therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

Extracellular vesicles (EVs), membrane vesicles that are secreted by a variety of mammalian cell types, have been shown to play an important role in intercellular communication. The contents of EVs, including proteins, microRNAs, and mRNAs, vary according to the cell type that secreted them. Accordingly, researchers have demonstrated that EVs derived from various cell types play different roles in biological phenomena. Considering the ubiquitous presence of mesenchymal stem cells (MSCs) in the body, MSC-derived EVs may take part in a wide range of events. In particular, MSCs have recently attracted much attention due to the therapeutic effects of their secretory factors. MSC-derived EVs may therefore provide novel therapeutic approaches. In this review, we first summarize the wide range of functions of EVs released from different cell types, emphasizing that EVs echo the phenotype of their parent cell. Then, we describe the various therapeutic effects of MSCs and pay particular attention to the significance of their paracrine effect. We then survey recent reports on MSC-derived EVs and consider the therapeutic potential of MSC-derived EVs. Finally, we discuss remaining issues that must be addressed before realizing the practical application of MSC-derived EVs, and we provide some suggestions for enhancing their therapeutic efficiency.

Human mesenchymal stem cells upregulate CD1dCD5(+) regulatory B cells in experimental autoimmune encephalomyelitis

BACKGROUND/AIMS

Multiple sclerosis (MS) causes significant neurological disability. Experimental autoimmune encephalomyelitis (EAE) is an animal model of MS. Human bone marrow mesenchymal stem cells (hMSCs) possess anti-inflammatory and immunosuppressive effects. We studied whether hMSCs affect CD1d(high)CD5(+) regulatory B-cell activity in EAE.

METHODS

EAE was induced in C57BL/6N mice by immunization with MOG35-55 peptide. hMSCs were injected intravenously into EAE mice on day 3 and day 12 after first immunization. Mice were sacrificed on day 26. Immunohistochemistry of the spinal cord, serum cytokines levels, production of cytokines by cultured splenic cells, and flow cytometry for splenic Th17 and CD1d(high)CD5(+) regulatory B cells were studied.

RESULTS

EAE mice with hMSC treatment on day 3 and day 12 had reduced EAE scores from day 14 to day 26 compared to EAE mice without hMSC treatment, and reduced infiltration of inflammatory cells and demyelination in the spinal cord. EAE mice with hMSC treatment on day 3 and day 12 had: (1) lower serum levels of IL-6, TNF-α (p < 0.0005), and IL-17 (p < 0.005 for day 3, p < 0.0005 for day 12); (2) reduced splenic cell production and secretion of IL-6, TNF-α (p < 0.05), and IL-17 (p < 0.05), and increased splenic production of IL-10; (3) reduced splenic Th17 cells (p < 0.05 for day 3, p < 0.005 for day 12), and (4) increased CD1d(high)CD5(+) regulatory B cells (p < 0.005) compared to EAE mice without hMSC treatment.

CONCLUSION

hMSC treatment on day 3 and day 12 suppresses EAE severity. The underlying mechanisms involve downregulation of Th17 cells and upregulation of CD1d(high)CD5(+) regulatory B-cell activity.

Stem cells in autoimmune diseases: Implications for pathogenesis and future trends in therapy

In this review we report the recent progresses, available in the literature, concerning the biology and the potential therapeutic role of both mesenchymal stem cells (MSCs) and hematopoietic stem cells in autoimmune diseases. Mesenchymal stem cells (MSCs) are responsible for the normal turnover and maintenance of adult mesenchymal tissues and their pleiotropic nature allows them to sense and respond to an event in the local environment, be it injury or inflammation. Recently, MSCs have been shown to have immune-modulatory properties and immunosuppressive capacities, acting on different immune cells both in vitro and in vivo, in addition to an immunologically privileged phenotype. Moreover, several works suggest that MSCs are defective in autoimmune diseases. These aspects are now considered the most intriguing aspect of their biology, introducing the possibility that these cells might be used as effective therapy in autoimmune diseases. Autoimmune diseases represent a failure of normal immune regulatory processes as they are characterized by activation and expansion of immune cell subsets in response to non-pathogenic stimuli. As autoimmune diseases can be transferred, or alternatively, cured, by stem cell transplantation, a defect in the hemopoietic stem cell as a cause of autoimmune diseases may be postulated. The rationale for autologous hematopoietic stem cell transplantation (HSCT) in autoimmune diseases is the ablation of an aberrant or self-reactive immune system by chemotherapy and regeneration of a new and hopefully self-tolerant immune system from hematopoietic stem cells. In the past 15years, more than 1500 patients worldwide have received HSCT, mostly autologous, as treatment for a severe autoimmune disease and the majority were affected by multiple sclerosis, systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis, juvenile idiopathic arthritis and idiopathic cytopenic purpura.

Distinct immunomodulatory and migratory mechanisms underpin the therapeutic potential of human mesenchymal stem cells in autoimmune demyelination

Mesenchymal stem cells (MSCs) are efficacious in a variety of intractable diseases. While bone marrow (BM)-derived MSCs (BM-MSCs) have been widely investigated, MSCs from other tissue sources have also been shown to be effective in several autoimmune and inflammatory disorders. In the present study, we simultaneously assessed the therapeutic efficacy of human BM-MSCs, as well as MSCs isolated from adipose tissue (Ad-MSCs) and umbilical cord Wharton's jelly (UC-MSCs), in experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). Prior to in vivo experiments, we characterized the phenotype and function of all three MSC types. We show that BM-MSCs were more efficient at suppressing the in vitro proliferation of mitogen or antigen-stimulated T-cell responses compared to Ad-MSCs and UC-MSCs. Notably BM-MSCs induced the differential expression of cytokines from normal and stimulated T-cells. Paradoxically, intravenous transplantation of BM-MSCs into C57Bl/6 mice with chronic progressive EAE had a negligible effect on the disease course, even when multiple MSC injections were administered over a number of time points. In contrast, Ad-MSCs had the most significant impact on clinical and pathological disease outcomes in chronic progressive and relapsing-remitting EAE models. In vivo tracking studies revealed that Ad-MSCs were able to migrate to the central nervous system (CNS), a property that most likely correlated with their broader expression of homing molecules, while BM-MSCs were not detected in this anatomic region. Collectively, this comparative investigation demonstrates that transplanted Ad-MSCs play a significant role in tissue repair processes by virtue of their ability to suppress inflammation coupled with their enhanced ability to home to the injured CNS. Given the access and relatively ease for harvesting adipose tissue, these data further implicate Ad-MSCs as a cell therapeutic that may be used to treat MS patients.

Immunosuppressive properties of mesenchymal stem cells

Mesenchymal stem cells (MSC) can be isolated from different adult tissues including bone marrow, adipose tissue, cord blood and placenta. MSCs modulate the immune function of the major immune cell populations involved in alloantigen recognition and elimination, including antigen presenting cells, T cells, B cells and natural killer cells. Many clinical trials are currently underway that employ MSCs to treat human immunological diseases. However, the molecular mechanism that mediates the immunosuppressive effect of MSCs is still unclear and the safety of using MSC in patient needs further confirmation. Here, we review the cytokines that activate MSCs and the soluble factors produced by MSCs, which allow them to exert their immunosuppressive effects. We review the mechanism responsible, at least in part, for the immune suppressive effects of MSCs and highlight areas of research required for a better understanding of MSC immune modulation.

Stem cell therapy for multiple sclerosis: preclinical evidence beyond all doubt?

Stem cell transplantation holds great promise for restoration of neural function in various neurodegenerative disorders, including multiple sclerosis (MS). However, many questions remain regarding the true efficacy and precise mode of action of stem cell-based therapeutic approaches. Therefore, in this article, we will first discuss the ideal route and/or timing of stem cell-based therapies for experimental autoimmune encephalomyelitis (EAE), the most used preclinical animal model for MS. Next, we will provide an overview of the proposed mechanisms that contribute to the beneficial effects of stem cell transplantation observed during the treatment of rodent EAE. Reviews of current and past literature clearly demonstrate conceptual changes in the development of stem cell-based approaches for EAE/MS, leading to the identification of several major challenges to be tackled before (stem) cell therapy for rodent EAE can be safely and successfully translated to human therapy for MS.