Harnessing the therapeutic potential of mesenchymal stem/stromal cell-derived extracellular vesicles as a novel cell-free therapy for animal models of multiple sclerosis.

Multiple sclerosis (MS) is a chronic, neuroinflammatory, and demyelinating disease of the central nervous system (CNS). Current treatments offer only limited relief from symptoms, and there is no cure. Mesenchymal stem/stromal cells (MSCs) have demonstrated therapeutic potential for MS. However, their clinical application faces challenges, including immune rejection and the potential for tumor formation. Recent studies suggest that MSCs exert their effects through extracellular vesicles (EVs) released from the cells, rather than direct cellular engraftment or differentiation. This discovery has sparked interest in the potential of MSC-derived EVs as a cell-free therapy for MS. This review explores the existing literature on the effects of MSC-EVs in animal models of MS. Administration of MSC-EVs from various tissue sources, such as bone marrow, adipose tissue, and umbilical cord, was found to reduce clinical scores and slow down disease progression in experimental autoimmune encephalomyelitis (EAE), the primary mouse model of MS. The mechanisms involved immunomodulation through effects on T cells, cytokines, CNS inflammation, and demyelination. Although the impact on CNS repair markers remained unclear, MSC-EVs exhibited the potential to modulate neuroinflammation and suppress harmful immune responses in EAE. Further studies are still required, but MSC-EVs demonstrate promising therapeutic effects for MS and warrant further exploration as a novel treatment approach.

The immunoregulatory and neuroprotective effects of human adipose derived stem cells overexpressing IL-11 and IL-13 in the experimental autoimmune encephalomyelitis mice.

Multiple sclerosis (MS) is an inflammatory demyelination disease in the central nervous system (CNS) characterized by incomplete endogenous remyelination in the chronic phase. A shift of the balance between pro and anti-inflammatory cytokines is one of the important markers in the pathogenesis of MS. This study aimed to evaluate the effects of human adipose derived stem cells (hADSCs) overexpressing interleukin 11 and interleukin 13 (IL-11, 13-hADSCs) on the experimental autoimmune encephalomyelitis (EAE), an animal model of MS.12 days after immunization of C57Bl/6 female mice with MOG35-55 and initial clinical symptoms appearance, the IL-11, 13-hADSCs were injected via the tail vein into the EAE mice. Then, the mice were sacrificed at 30 days post-immunization (DPI) and the spinal cords of experimental groups were extracted for histopathological and real-time RT-PCR studies.The results indicated that the clinical scores and mononuclear cells infiltration into the spinal cords of EAE mice were significantly reduced in mice treated with IL-11, 13-hADSCs. Likewise, the remyelination and oligodendrogenesis were significantly enhanced in the mentioned treatment group. Real-time results demonstrated that pro/anti-inflammatory cytokine genes expression was reversed in IL-11, 13-hADSCs treatment group in comparison to the untreated EAE group.Expression of IL-11 as a neurotrophic cytokine and IL-13 as an anti-inflammatory cytokine by hADSCs could increase the immunomodulatory and neuroprotective effects of hADSCs and be a powerful candidate in stem cell therapy for future treatment of MS.

Therapeutic effects of extracellular vesicles from human adipose-derived mesenchymal stem cells on chronic experimental autoimmune encephalomyelitis.

Since in cell therapy, there are always concerns about immune rejection, genetic disability, and malignancies, special attention has been paid to extracellular vesicles (EVs) which are secreted by mesenchymal stem cells (MSCs). In the present study, we assessed and compared the therapeutic effects of human adipose-derived mesenchymal stem cells (hADSC) and hADSC-EVs from adipose tissue on experimental autoimmune encephalomyelitis (EAE). After induction of EAE in C57Bl/6 mice, they were treated with hADSCs, hADSC-EVs, or vehicle intravenously. The clinical score of all mice was recorded every other day. Mice were killed at Day 30 and splenocytes were isolated for proliferation assay and determination of the frequency of Treg cells by flow cytometry. Leukocyte infiltration by hematoxylin and eosin, percentages of demyelination areas by luxol fast blue, and mean fluorescence intensity of oligodendrocyte transcription factor 2 (OLIG2) and myelin basic protein (MBP) by immunohistochemistry were assessed in the spinal cord. Our results showed that the maximum mean clinical score and myelin oligodendrocyte glycoprotein-induced proliferation of splenocytes in hADSC- and hADSC-EV-treated mice were significantly lower than the control mice (p < .05). We also demonstrated that the frequency of CD4+ CD25+ Foxp3+ cells was significantly higher in the spleen of hADSC-treated mice than EAE control mice (p = .023). The inflammation score and the percentages of demyelination areas in hADSC- and hADSC-EV-treated groups significantly declined compared with the untreated control group (p < .05). We also showed that there was no significant difference in MFI of MBP and OLIG2 in the spinal cord of studied groups. Overall, we suggest that intravenous administration of hADSC-EVs attenuates the induced EAE through diminishing proliferative potency of T cells, mean clinical score, leukocyte infiltration, and demyelination in a chronic model of multiple sclerosis.