Mesenchymal stem cells in a transgenic mouse model of multiple system atrophy: immunomodulation and neuroprotection

The emerging role of extracellular vesicles in the diagnosis and treatment of autism spectrum disorders

Autism spectrum disorders (ASD) are neurodevelopmental conditions characterized by restricted, repetitive behavioral patterns and deficits in social interactions. The prevalence of ASD has continued to rise in recent years. However, the etiology and pathophysiology of ASD remain largely unknown. Currently, the diagnosis of ASD relies on behavior measures, and there is a lack of reliable and objective biomarkers. In addition, there are still no effective pharmacologic therapies for the core symptoms of ASD. Extracellular vesicles (EVs) are lipid bilayer nanovesicles secreted by almost all types of cells. EVs play a vital role in cell-cell communications and are known to bear various biological functions. Emerging evidence demonstrated that EVs are involved in many physiological and pathological processes throughout the body and the content in EVs can reflect the status of the originating cells. EVs have demonstrated the potential of broad applications for the diagnosis and treatment of various brain diseases, suggesting that EVs may have also played a role in the pathological process of ASD. Besides, EVs can be utilized as therapeutic agents for their endogenous substances and biological functions. Additionally, EVs can serve as drug delivery tools as nano-sized vesicles with inherent targeting ability. Here, we discuss the potential of EVs to be considered as promising diagnostic biomarkers and their potential therapeutic applications for ASD.

An update on multiple system atrophy

PURPOSE OF REVIEW

Multiple system atrophy (MSA) is a rapidly progressive synucleinopathy characterized by autonomic failure, parkinsonism, and cerebellar ataxia. Here, we provide an update on α-synuclein's role in MSA pathophysiology and review the new Movement Disorders Society (MDS) diagnostic criteria and the utility of α-synuclein-based biomarkers. We also highlight ongoing efforts toward clinical trial readiness and review potential disease-modifying therapies undergoing clinical trials.

RECENT FINDINGS

A role of urinary tract infections in triggering α-synuclein aggregation and contribution of genes implicated in oligodendroglial development have been suggested in the MSA pathophysiology. The clinically probable MSA category of the new diagnostic criteria shows improved accuracy in early disease stages. Predictors of phenoconversion from pure autonomic failure to MSA are now better defined. Alpha-synuclein strains in CSF and serum, phosphorylated α-synuclein deposits in the skin, and brain α-synuclein pathology visualized using PET ligand [18F]ACI-12589 are emerging as valuable diagnostic tools. Clinical trials in MSA investigate drugs targeting α-synuclein aggregation or preventing α-synuclein expression, along with stem cell and gene therapies to halt disease progression.

SUMMARY

New MSA diagnostic criteria and α-synuclein-based biomarkers may enhance diagnostic accuracy while promising therapies are in development to address disease progression.

Multiple system atrophy: an update and emerging directions of biomarkers and clinical trials

Multiple system atrophy is a rare, debilitating, adult-onset neurodegenerative disorder that manifests clinically as a diverse combination of parkinsonism, cerebellar ataxia, and autonomic dysfunction. It is pathologically characterized by oligodendroglial cytoplasmic inclusions containing abnormally aggregated α-synuclein. According to the updated Movement Disorder Society diagnostic criteria for multiple system atrophy, the diagnosis of clinically established multiple system atrophy requires the manifestation of autonomic dysfunction in combination with poorly levo-dopa responsive parkinsonism and/or cerebellar syndrome. Although symptomatic management of multiple system atrophy can substantially improve quality of life, therapeutic benefits are often limited, ephemeral, and they fail to modify the disease progression and eradicate underlying causes. Consequently, effective breakthrough treatments that target the causes of disease are needed. Numerous preclinical and clinical studies are currently focusing on a set of hallmarks of neurodegenerative diseases to slow or halt the progression of multiple system atrophy: pathological protein aggregation, synaptic dysfunction, aberrant proteostasis, neuronal inflammation, and neuronal cell death. Meanwhile, specific biomarkers and measurements with higher specificity and sensitivity are being developed for the diagnosis of multiple system atrophy, particularly for early detection of the disease. More intriguingly, a growing number of new disease-modifying candidates, which can be used to design multi-targeted, personalized treatment in patients, are being investigated, notwithstanding the failure of most previous attempts.

Inflammatory diseases: Function of LncRNAs in their emergence and the role of mesenchymal stem cell secretome in their treatment

One of the best treatments for inflammatory diseases such as COVID-19, respiratory diseases and brain diseases is treatment with stem cells. Here we investigate the effect of stem cell therapy in the treatment of brain diseases.Preclinical studies have shown promising results, including improved functional recovery and tissue repair in animal models of neurodegenerative diseases, strokes,and traumatic brain injuries. However,ethical implications, safety concerns, and regulatory frameworks necessitate thorough evaluation before transitioning to clinical applications. Additionally, the complex nature of the brain and its intricate cellular environment present unique obstacles that must be overcome to ensure the successful integration and functionality of genetically engineered MSCs. The careful navigation of this path will determine whether the application of genetically engineered MSCs in brain tissue regeneration ultimately lives up to the hype surrounding it.

A Mouse Model of Multiple System Atrophy: Bench to Bedside

Multiple system atrophy (MSA) is a rare neurodegenerative disorder with unclear etiology, currently difficult and delayed diagnosis, and rapid progression, leading to disability and lethality within 6 to 9 years after symptom onset. The neuropathology of MSA classifies the disease in the group of a-synucleinopathies together with Parkinson's disease and other Lewy body disorders, but features specific oligodendroglial inclusions, which are pathognomonic for MSA. MSA has no efficient therapy to date. Development of experimental models is crucial to elucidate the disease mechanisms in progression and to provide a tool for preclinical screening of putative therapies for MSA. In vitro and in vivo models, based on selective neurotoxicity, a-synuclein oligodendroglial overexpression, and strain-specific propagation of a-synuclein fibrils, have been developed, reflecting various facets of MSA pathology. Over the years, the continuous exchange from bench to bedside and backward has been crucial for the advancing of MSA modelling, elucidating MSA pathogenic pathways, and understanding the existing translational gap to successful clinical trials in MSA. The review discusses specifically advantages and limitations of the PLP-a-syn mouse model of MSA, which recapitulates motor and non-motor features of the human disease with underlying striatonigral degeneration, degeneration of autonomic centers, and sensitized olivopontocerebellar system, strikingly mirroring human MSA pathology.

Disease-Modifying Therapies for Multiple System Atrophy: Where Are We in 2022?

Multiple system atrophy is a rapidly progressive and fatal neurodegenerative disorder. While numerous preclinical studies suggested efficacy of potentially disease modifying agents, none of those were proven to be effective in large-scale clinical trials. Three major strategies are currently pursued in preclinical and clinical studies attempting to slow down disease progression. These target α-synuclein, neuroinflammation, and restoration of neurotrophic support. This review provides a comprehensive overview on ongoing preclinical and clinical developments of disease modifying therapies. Furthermore, we will focus on potential shortcomings of previous studies that can be avoided to improve data quality in future studies of this rare disease.

Extracellular Vesicles Released from Neprilysin Gene-Modified Human Umbilical Cord-Derived Mesenchymal Stem Cell Enhance Therapeutic Effects in an Alzheimer's Disease Animal Model

Alzheimer's disease (AD) animal studies have reported that mesenchymal stem cells (MSCs) have therapeutic effects; however, clinical trial results are controversial. Neprilysin (NEP) is the main cleavage enzyme of β-amyloid (Aβ), which plays a major role in the pathology and etiology of AD. We evaluated whether transplantation of MSCs with NEP gene modification enhances the therapeutic effects in an AD animal model and then investigated these pathomechanisms. We manufactured NEP gene-enhanced human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) and intravenously transplanted them in Aβ_1-42-injected AD animal models. We compared the differences in behavioral tests and immunohistochemical assays between four groups: normal, Aβ_1-42 injection, naïve hUC-MSCs, and NEP-enhanced hUC-MSCs. Both naïve and NEP-enhanced hUC-MSC groups showed significant improvements in memory compared to the Aβ_1-42 injection group. There was no significant difference between naïve and NEP-enhanced hUC-MSC groups. There was a significant decrease in Congo red, BACE-1, GFAP, and Iba-1 and a significant increase in BDNF, NeuN, and NEP in both hUC-MSC groups compared to the Aβ_1-42 injection group. Among them, BDNF, NeuN, GFAP, Iba-1, and NEP showed more significant changes in the NEP-enhanced hUC-MSC group than in the naïve group. After stem cell injection, stem cells were not found. Extracellular vesicles (EVs) were equally observed in the hippocampus in the naïve and NEP-enhanced hUC-MSC groups. However, the EVs of NEP-enhanced hUC-MSCs contained higher amounts of NEP as compared to the EVs of naïve hUC-MSCs. Thus, hUC-MSCs affect AD animal models through stem cell-released EVs. Although there was no significant difference in cognitive function between the hUC-MSC groups, NEP-enhanced hUC-MSCs had superior neurogenesis and anti-inflammation properties compared to naïve hUC-MSCs due to increased NEP in the hippocampus by enriched NEP-possessing EVs. NEP gene-modified MSCs that release an increased amount of NEP within EVs may be a promising therapeutic option in AD treatment.

Efficacy of Human Umbilical Cord Blood-Mononuclear Cell Transplantation for MSA Treatment and Its Effects on Changes in T-Cell Subsets in Peripheral Blood and Inflammatory Factors

Objective

This study is aimed at examining the efficacy of human umbilical cord blood-mononuclear cell (hUCB-MNCs) transplantation through lateral atlanto-occipital space puncture in multiple system atrophy (MSA) treatment and investigating changes in T-cell subsets in peripheral blood and inflammatory factors in patients before and after treatment.

Methods

A total of 20 patients with MSA who underwent hUCB-MNC transplantation through lateral atlanto-occipital space puncture in the Liaocheng People's Hospital were enrolled. Patients were followed up at 0, 1, 3, and 6 months after treatment, and the Unified Multiple System Atrophy Rating Scale (UMSARS) scores, TNF-α in the peripheral blood, IL-6, percentage of CD4, and CD4/CD8 ratio were evaluated and compared for each follow-up point; any adverse effects were recorded.

Results

UMSARS Part I scores were 20.55 ± 3.80, 19.20 ± 3.78, and 19.40 ± 4.11, 1, 3, and 6 months, respectively, after treatment and were significantly lower as compared to that before treatment (23.50 ± 4.72; P < 0.05). Similarly, UMSARS Part II scores 1, 3, and 6 months after treatment were 25.50 ± 5.01, 24.05 ± 5.01, and 24.25 ± 5.05, respectively, significantly lower as compared to that before treatment (30.15 ± 5.63; P < 0.05). The IL-6 values in the peripheral blood 1, 3, and 6 months after treatment were 5.25 ± 2.70 pg/m, 2.96 ± 1.75 pg/m, and 3.31 ± 1.62 pg/m, respectively, which were significantly lower (P < 0.05) than that before treatment (8.22 ± 4.69) pg/m. The TNF-α levels at 3 and 6 months after treatment were 13.08 ± 6.13 pg/m and 12.24 ± 4.76 pg/m, respectively, which were significantly lower than that before treatment (22.99 ± 13.30; P < 0.01). The CD4/CD8 ratios in the peripheral blood 1, 3, and 6 months after treatment were 1.09 ± 0.25, 1.30 ± 0.24, and 1.43 ± 0.22, respectively, which were significantly different than that before treatment (0.81 ± 0.24, P < 0.01). Similarly, the CD4 percentages 1, 3, and 6 months after treatment were 34.09 ± 1.79, 36.05 ± 1.50, and 36.47 ± 1.47, respectively, which were significantly different than that before treatment (0.81 ± 0.24; P < 0.01).

Conclusion

hUCB-MNC transplantation through lateral atlanto-occipital space puncture could significantly improve the symptoms and signs in patients with MSA and delay the disease progression. Thus, hUCB-MNCs may modulate immune activity and reduce the inflammatory response.

Phase I Trial of Intra-arterial Administration of Autologous Bone Marrow-Derived Mesenchymal Stem Cells in Patients with Multiple System Atrophy

BACKGROUND

This study is aimed at investigating the safety and tolerability of the intra-arterial administration of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) in patients with multiple system atrophy- (MSA-) cerebellar type (MSA-C).

METHODS

This was a single-center, open-label phase I clinical trial in patients with MSA-C. A three-stage dose escalation scheme (low-dose, 3.0 × 105 cells/kg; medium-dose, 6.0 × 105 cells/kg; high-dose, 9.0 × 105 cells/kg) was applied to determine the maximum tolerated dose of intra-arterial administration of BM-MSCs based on the no-observed-adverse-effect level derived from the toxicity study. The occurrence of adverse events was evaluated 1 day before and 1, 14, and 28 days after BM-MSC therapy. Additionally, we assessed changes in the Unified MSA Rating Scale (UMSARS) score 3 months after BM-MSC treatment.

RESULTS

One serious adverse drug reaction (ADR) of leptomeningeal enhancement following the intra-arterial BM-MSC administration occurred in one patient in the low-dose group. The safety review of the Internal Monitoring Committee interpreted this as radiological evidence of the blood-brain barrier permeability for MSCs. No other ADRs were observed in the medium- or high-dose groups. In particular, no ischemic lesions on diffusion-weighted images were observed in any of the study participants. Additionally, the medium- and high-dose groups tended to show a slower increase in UMSARS scores than the low-dose group during the 3-month follow-up.

CONCLUSION

The present study confirmed that a single intra-arterial administration of autologous BM-MSCs is a safe and promising neuroprotective strategy in patients with MSA-C.

A historical review of multiple system atrophy with a critical appraisal of cellular and animal models

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by striatonigral degeneration (SND), olivopontocerebellar atrophy (OPCA), and dysautonomia with cerebellar ataxia or parkinsonian motor features. Isolated autonomic dysfunction with predominant genitourinary dysfunction and orthostatic hypotension and REM sleep behavior disorder are common characteristics of a prodromal phase, which may occur years prior to motor-symptom onset. MSA is a unique synucleinopathy, in which alpha-synuclein (aSyn) accumulates and forms insoluble inclusions in the cytoplasm of oligodendrocytes, termed glial cytoplasmic inclusions (GCIs). The origin of, and precise mechanism by which aSyn accumulates in MSA are unknown, and, therefore, disease-modifying therapies to halt or slow the progression of MSA are currently unavailable. For these reasons, much focus in the field is concerned with deciphering the complex neuropathological mechanisms by which MSA begins and progresses through the course of the disease. This review focuses on the history, etiopathogenesis, neuropathology, as well as cell and animal models of MSA.

Novel Therapies for Parkinsonian Syndromes-Recent Progress and Future Perspectives

Background: Atypical parkinsonian syndromes are rare, fatal neurodegenerative diseases associated with abnormal protein accumulation in the brain. Examples of these syndromes include progressive supranuclear palsy, multiple system atrophy, and corticobasal degeneration. A common clinical feature in parkinsonism is a limited improvement with levodopa. So far, there are no disease-modifying treatments to address these conditions, and therapy is only limited to the alleviation of symptoms. Diagnosis is devastating for patients, as prognosis is extremely poor, and the disease tends to progress rapidly. Currently, potential causes and neuropathological mechanisms involved in these diseases are being widely investigated. Objectives: The goal of this review is to summarize recent advances and gather emerging disease-modifying therapies that could slow the progression of atypical parkinsonian syndromes. Methods: PubMed and Google Scholar databases were searched regarding novel perspectives for atypical parkinsonism treatment. The following medical subject headings were used: "atypical parkinsonian syndromes-therapy," "treatment of atypical parkinsonian syndromes," "atypical parkinsonian syndromes-clinical trial," "therapy of tauopathy," "alpha-synucleinopathy treatment," "PSP therapy/treatment," "CBD therapy/treatment," "MSA therapy/treatment," and "atypical parkinsonian syndromes-disease modifying." All search results were manually reviewed prior to inclusion in this review. Results: Neuroinflammation, mitochondrial dysfunction, microglia activation, proteasomal impairment, and oxidative stress play a role in the neurodegenerative process. Ongoing studies and clinical trials target these components in order to suppress toxic protein accumulation. Various approaches such as stem cell therapy, anti-aggregation/anti-phosphorylation agent administration, or usage of active and passive immunization appear to have promising results. Conclusion: Presently, disease-modifying strategies for atypical parkinsonian syndromes are being actively explored, with encouraging preliminary results. This leads to an assumption that developing accurate, safe, and progression-halting treatment is not far off. Nevertheless, the further investigation remains necessary.

Intrathecal Transplantation of Autologous and Allogeneic Bone Marrow-Derived Mesenchymal Stem Cells in Dogs

The route used in the transplantation of mesenchymal stem cells (MSCs) can directly affect the treatment success. The transplantation of MSCs via the intrathecal (IT) route can be an important therapeutic strategy for neurological disorders. The objective of this study was to evaluate the safety and feasibility of the IT transplantation of autologous (Auto-MSCs) and allogeneic (Allo-MSCs) bone marrow mesenchymal stem cells (BM-MSCs) in healthy dogs. Based on neurodisability score, cerebrospinal fluid (CSF) and magnetic resonance imaging (MRI), no significant differences from the control group were observed on day 1 or day 5 after IT Auto- or Allo-MSCs transplantation (P > 0.05). In addition, analysis of matrix metalloproteinase (MMP)-2 and MMP-9 expression in the CSF revealed no significant differences (P > 0.05) at 5 days after IT transplantation in the Auto- or Allo-MSCs group when compared to the control. Intrathecal transplantation of BM-MSCs in dogs provides a safe, easy and minimally invasive route for the use of cell-based therapeutics in central nervous system diseases.

Current experimental disease-modifying therapeutics for multiple system atrophy

Multiple system atrophy (MSA) is a challenging neurodegenerative disorder with a difficult and often inaccurate early diagnosis, still lacking effective treatment. It is characterized by a highly variable clinical presentation with parkinsonism, cerebellar ataxia, autonomic dysfunction, and pyramidal signs, with a rapid progression and an aggressive clinical course. The definite MSA diagnosis is only possible post-mortem, when the presence of distinctive oligodendroglial cytoplasmic inclusions (GCIs), mainly composed of misfolded and aggregated α-Synuclein (α-Syn) is demonstrated. The process of α-Syn accumulation and aggregation within oligodendrocytes is accepted one of the main pathological events underlying MSA. However, MSA is considered a multifactorial disorder with multiple pathogenic events acting together including neuroinflammation, oxidative stress, and disrupted neurotrophic support, among others. The discussed here treatment approaches are based on our current understanding of the pathogenesis of MSA and the results of preclinical and clinical therapeutic studies conducted over the last 2 decades. We summarize leading disease-modifying approaches for MSA including targeting α-Syn pathology, modulation of neuroinflammation, and enhancement of neuroprotection. In conclusion, we outline some challenges related to the need to overcome the gap in translation between preclinical and clinical studies towards a successful disease modification in MSA.

Stem cell therapy in coronavirus disease 2019: current evidence and future potential

The end of 2019 saw the beginning of the coronavirus disease 2019 (COVID-19) pandemic that soared in 2020, affecting 215 countries worldwide, with no signs of abating. In an effort to contain the spread of the disease and treat the infected, researchers are racing against several odds to find an effective solution. The unavailability of timely and affordable or definitive treatment has caused significant morbidity and mortality. Acute respiratory distress syndrome (ARDS) caused by an unregulated host inflammatory response toward the viral infection, followed by multi-organ dysfunction or failure, is one of the primary causes of death in severe cases of COVID-19 infection. Currently, empirical management of respiratory and hematological manifestations along with anti-viral agents is being used to treat the infection. The quest is on for both a vaccine and a more definitive management protocol to curtail the spread. Researchers and clinicians are also exploring the possibility of using cell therapy for severe cases of COVID-19 with ARDS. Mesenchymal stromal cells are known to have immunomodulatory properties and have previously been used to treat viral infections. This review explores the potential of mesenchymal stromal cells as cell therapy for ARDS.

Current Management and Emerging Therapies in Multiple System Atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative disease variably associated with motor, nonmotor, and autonomic symptoms, resulting from putaminal and cerebellar degeneration and associated with glial cytoplasmic inclusions enriched with α-synuclein in oligodendrocytes and neurons. Although symptomatic treatment of MSA can provide significant improvements in quality of life, the benefit is often partial, limited by adverse effects, and fails to treat the underlying cause. Consistent with the multisystem nature of the disease and evidence that motor symptoms, autonomic failure, and depression drive patient assessments of quality of life, treatment is best achieved through a coordinated multidisciplinary approach driven by the patient's priorities and goals of care. Research into disease-modifying therapies is ongoing with a particular focus on synuclein-targeted therapies among others. This review focuses on both current management and emerging therapies for this devastating disease.

Ischemia-Induced Multipotent Stem Cells Isolated from Stroke Patients Exhibit Higher Neurogenic Differentiation Potential than Bone Marrow-Derived Mesenchymal Stem Cells

Perivascular areas of the brain harbor multipotent stem cells. We recently demonstrated that after a stroke, brain pericytes exhibit features of multipotent stem cells. Moreover, these ischemia-induced multipotent stem cells (iSCs) are present within ischemic areas of the brain of patients diagnosed with stroke. Although increasing evidence shows that iSCs have traits similar to those of mesenchymal stem cells (MSCs), the phenotypic similarities and differences between iSCs and MSCs remain unclear. In this study, we used iSCs extracted from stroke patients (h-iSCs) and compared their neurogenic potential with that of human MSCs (h-MSCs) in vitro. Microarray analysis, fluorescence-activated cell sorting, immunohistochemistry, and multielectrode array were performed to compare the characteristics of h-iSCs and h-MSCs. Although h-iSCs and h-MSCs had similar gene expression profiles, the percentage expressing the neural stem/progenitor cell marker nestin was significantly higher in h-iSCs than in h-MSCs. Consistent with these findings, h-iSCs, but not h-MSCs, differentiated into electrophysiologically functional neurons. In contrast, although both h-iSCs and h-MSCs were able to differentiate into several mesodermal lineages, including adipocytes, osteocytes, and chondrocytes, the potential of h-iSCs to differentiate into adipocytes and osteocytes was relatively low. These results suggest that compared with h-MSCs, h-iSCs predominantly exhibit neural rather than mesenchymal lineages. In addition, these results indicate that h-iSCs have the potential to repair the injured brain of patients with stroke by directly differentiating into neuronal lineages.

Prevention of multiple system atrophy using human bone marrow-derived mesenchymal stem cells by reducing polyamine and cholesterol-induced neural damages

Background

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology, but is closely associated with damage to dopaminergic neurons. MSA progression is rapid. Hence, long-term drug treatments do not have any therapeutic benefits. We assessed the inhibitory effect of mesenchymal stem cells (MSCs) on double-toxin-induced dopaminergic neurodegenerative MSA.

Results

Behavioral disorder was significantly improved and neurodegeneration was prevented following MSC transplantation. Proteomics revealed lower expression of polyamine modulating factor-binding protein 1 (PMFBP1) and higher expression of 3-hydroxymethyl-3-methylglutaryl-CoA lyase (HMGCL), but these changes were reversed after MSC transplantation. In the in vitro study, the 6-OHDA-induced effects were reversed following co-culture with MSC. However, PMFBP1 knockdown inhibited the recovery effect due to the MSCs. Furthermore, HMGCL expression was decreased following co-culture with MSCs, but treatment with recombinant HMGCL protein inhibited the recovery effects due to MSCs.

Conclusions

These data indicate that MSCs protected against neuronal loss in MSA by reducing polyamine- and cholesterol-induced neural damage.

MSA: From basic mechanisms to experimental therapeutics

Multiple system atrophy (MSA) is a rare and fatal neurodegenerative disorder characterized by rapidly progressive autonomic and motor dysfunction. Pathologically, MSA is mainly characterized by the abnormal accumulation of misfolded α-synuclein in the cytoplasm of oligodendrocytes, which plays a major role in the pathogenesis of the disease. Striatonigral degeneration and olivopontecerebellar atrophy underlie the motor syndrome, while degeneration of autonomic centers defines the autonomic failure in MSA. At present, there is no treatment that can halt or reverse its progression. However, over the last decade several studies in preclinical models and patients have helped to better understand the pathophysiological events underlying MSA. The etiology of this fatal disorder remains unclear and may be multifactorial, caused by a combination of factors which may serve as targets for novel therapeutic approaches. In this review, we summarize the current knowledge about the etiopathogenesis and neuropathology of MSA, its different preclinical models, and the main disease modifying therapies that have been used so far or that are planned for future clinical trials.

Intrathecal administration of autologous mesenchymal stem cells in multiple system atrophy

OBJECTIVE

This phase I/II study sought to explore intrathecal administration of mesenchymal stem cells (MSCs) as therapeutic approach to multiple system atrophy (MSA).

METHODS

Utilizing a dose-escalation design, we delivered between 10 and 200 million adipose-derived autologous MSCs intrathecally to patients with early MSA. Patients were closely followed with clinical, laboratory, and imaging surveillance. Primary endpoints were frequency and type of adverse events; key secondary endpoint was the rate of disease progression assessed by the Unified MSA Rating Scale (UMSARS).

RESULTS

Twenty-four patients received treatment. There were no attributable serious adverse events, and injections were generally well-tolerated. At the highest dose tier, 3 of 4 patients developed low back/posterior leg pain, associated with thickening/enhancement of lumbar nerve roots. Although there were no associated neurologic deficits, we decided that dose-limiting toxicity was reached. A total of 6 of 12 patients in the medium dose tier developed similar, but milder and transient discomfort. Rate of progression (UMSARS total) was markedly lower compared to a matched historical control group (0.40 ± 0.59 vs 1.44 ± 1.42 points/month, p = 0.004) with an apparent dose-dependent effect.

CONCLUSIONS

Intrathecal MSC administration in MSA is safe and well-tolerated but can be associated with a painful implantation response at high doses. Compelling dose-dependent efficacy signals are the basis for a planned placebo-controlled trial.

CLASSIFICATION OF EVIDENCE

This phase I/II study provides Class IV evidence that for patients with early MSA, intrathecal MSC administration is safe, may result in a painful implantation response at high doses, and is associated with dose-dependent efficacy signals.

Mesenchymal Stromal Cell Therapies for Neurodegenerative Diseases

Mesenchymal stromal cells are multipotent cells that are being used to treat a variety of medical conditions. Over the past decade, there has been considerable excitement about using MSCs to treat neurodegenerative diseases, which are diseases that are typically fatal and without other robust therapies. In this review, we discuss the proposed MSC mechanisms of action in neurodegenerative diseases, which include growth factor secretion, exosome secretion, and attenuation of neuroinflammation. We then provide a summary of preclinical and early clinical work on MSC therapies in amyotrophic lateral sclerosis, multiple system atrophy, Parkinson disease, and Alzheimer disease. Continued rigorous and controlled studies of MSC therapies will be critical in order to establish efficacy and protect patients from possible untoward effects.

Bone Marrow Mesenchymal Stem Cell Transplantation Enhances Nerve Regeneration in a Rat Model of Hindlimb Replantation

BACKGROUND

Successful limb replantation must be based not only on the viability of the amputated part but also on satisfactory long-term functional recovery. Once the vascular, skeletal, and soft-tissue problems have been taken care of, nerve recovery becomes the ultimate limiting factor. Unfortunately, nerve regeneration after limb replantation is impaired by several consequences. The authors tested the hypothesis that bone marrow mesenchymal stem cells could improve nerve regeneration outcomes in an experimental model of limb replantation.

METHODS

Twenty rats underwent replantation after total hindlimb amputation. Animals were subdivided into two groups: a replanted but nontreated control group and a replanted and bone marrow mesenchymal stem cell-transplanted group. Three months after surgery, nerve regeneration was assessed using functional, electrophysiologic, histomorphologic, and immunohistochemical analyses.

RESULTS

Bone marrow mesenchymal stem cell-treated animals showed significantly better sciatic functional index levels and higher compound muscle action potential amplitudes in comparison with the controls. Histomorphometric analysis revealed that the number of regenerating axons was approximately two-fold greater in the treated nerves. In addition, the mean g-ratio of these axons was within the optimal range. Immunohistochemical assessment revealed that expression of S-100 and myelin basic protein in the treated nerves was significantly higher than in controls. Correspondingly, the expression levels of anti-protein gene product 9.5 and vesicular acetylcholine transporter in motor endplates were also significantly higher. Finally, muscles in the bone marrow mesenchymal stem cell-transplanted group showed significantly larger average fiber areas.

CONCLUSION

The authors' findings demonstrate that it is possible to improve the degree of nerve regeneration after limb replantation by bone marrow mesenchymal stem cell transplantation.

TNFα inhibitors as targets for protective therapies in MSA: a viewpoint

Multiple system atrophy (MSA) is a unique and fatal α-synucleinopathy associated with oligodendroglial inclusions and secondary neurodegeneration affecting striatum, substantia nigra, pons, and cerebellum. The pathogenesis remains elusive; however, there is emerging evidence suggesting a prominent role of neuroinflammation. Here, we critically review the relationship between αS and microglial activation depending on its aggregation state and its role in neuroinflammation to explore the potential of TNFα inhibitors as a treatment strategy for MSA and other neurodegenerative diseases.

Treatment of multiple system atrophy - the past, present and future

Multiple system atrophy is a sporadic progressive degenerative disease which is characterized by multiple central nervous systems involved. So far, there is no effective medicine to cure MSA. The main research direction of treatment includes immunization transplantation and cytotherapy. Human umbilical cord blood is the residue of blood in the placenta and umbilical cord after fetal delivery. It is the most abundant cell bank and its usage is not limited to treat hematological diseases. The researches about hUCB-MNC treatment on MSA are increasing gradually. The potential of other MSC is also discussed. Lateral atlanto-occipital space puncture is an ingenious way created by Professor Dianrong Gong. More than 30 cases of MSA have been treated by this method with fine clinical effect and without serious complications. It indicates that stem cells treatment is a valid method for refractory nerve system diseases.

Comparative Characterization of Ischemia-Induced Brain Multipotent Stem Cells with Mesenchymal Stem Cells: Similarities and Differences

Mesenchymal stem cells (MSCs) are multipotent stem cells localized to the perivascular regions of various organs, including bone marrow (BM). While MSC transplantation represents a promising stem cell-based therapy for ischemic stroke, increasing evidence indicates that exogenously administered MSCs rarely accumulate in the injured central nervous system (CNS). Therefore, compared with MSCs, regionally derived brain multipotent stem cells may be a superior source to elicit regeneration of the CNS following ischemic injury. We previously identified ischemia-induced multipotent stem cells (iSCs) as likely originating from brain pericytes/perivascular cells (PCs) within poststroke regions. However, detailed characteristics of iSCs and their comparison with MSCs remains to be investigated. In the present study, we compared iSCs with BM-derived MSCs, with a focus on the stemness and neuron-generating activity of each cell type. From our results, stem and undifferentiated cell markers, including c-myc and Klf4, were found to be expressed in iSCs and BM-MSCs. In addition, both cell types exhibited the ability to differentiate into mesoderm lineages, including as osteoblasts, adipocytes, and chondrocytes. However, compared with BM-MSCs, high expression of neural stem cell markers, including nestin and Sox2, were found in iSCs. In addition, iSCs, but not BM-MSCs, formed neurosphere-like cell clusters that differentiated into functional neurons. These results demonstrate that iSCs are likely multipotent stem cells with the ability to differentiate into not only mesoderm, but also neural, lineages. Collectively, our novel findings suggest that locally induced iSCs may contribute to CNS repair by producing neuronal cells following ischemic stroke.

Translational therapies for multiple system atrophy: Bottlenecks and future directions

Over the last decade a prominent amount of studies in preclinical transgenic models of multiple system atrophy (MSA) has been performed. These studies have helped understand mechanisms downstream to the α-synuclein oligodendroglial accumulation relevant to human MSA. However, the successful translation of the preclinical outcomes into a clinical trial has failed. Looking back, we can now identify possible confounders for the failure. Biomarkers of disease progression are mostly missing. Early diagnosis and initiation of therapeutic clinical trials is limited. The need of both proof-of-concept as well as clinically relevant preclinical study designs with clinically relevant timing and preclinical readouts is identified as a must in our translational efforts for MSA to date. Finally, improved clinical study designs with improved enrollment criteria, and measurement outcomes are warranted on the way to finding the successful therapeutic approach for MSA. This review provides an overview of experimental studies and clinical trials for MSA and the lessons learned over the last decade towards the identification of the cure for MSA.

Mesenchymal Stem Cells Stabilize Axonal Transports for Autophagic Clearance of α-Synuclein in Parkinsonian Models

Genome-wide association studies have identified two loci, SNCA and the microtubule (MT)-associated protein tau, as common risk factors for Parkinson's disease (PD). Specifically, α-synuclein directly destabilizes MT via tau phosphorylation and induces axonal transport deficits that are the primary events leading to an abnormal accumulation of α-synuclein that causes nigral dopaminergic cell loss. In this study, we demonstrated that mesenchymal stem cells (MSCs) could modulate cytoskeletal networks and trafficking to exert neuroprotective properties in wild-type or A53T α-synuclein overexpressing cells and mice. Moreover, we found that eukaryotic elongation factor 1A-2, a soluble factor derived from MSCs, stabilized MT assembly by decreasing calcium/calmodulin-dependent tau phosphorylation and induced autophagolysosome fusion, which was accompanied by an increase in the axonal motor proteins and increased neuronal survival. Our data suggest that MSCs have beneficial effects on axonal transports via MT stability by controlling α-synuclein-induced tau phosphorylation, indicating that MSCs may exert a protective role in the early stages of axonal transport defects in α-synucleinopathies. Stem Cells 2017;35:1934-1947.

Neuroinflammation as modifier of genetically caused neurological disorders of the central nervous system: Understanding pathogenesis and chances for treatment

Genetically caused neurological disorders of the central nervous system (CNS) are usually orphan diseases with poor or even fatal clinical outcome and few or no treatments that will improve longevity or at least quality of life. Neuroinflammation is common to many of these disorders, despite the fact that a plethora of distinct mutations and molecular changes underlie the disorders. In this article, data from corresponding animal models are analyzed to define the roles of innate and adaptive inflammation as modifiers and amplifiers of disease. We describe both common and distinct patterns of neuroinflammation in genetically mediated CNS disorders and discuss the contrasting mechanisms that lead to adverse versus neuroprotective effects. Moreover, we identify the juxtaparanode as a neuroanatomical compartment commonly associated with inflammatory cells and ongoing axonopathic changes, in models of diverse diseases. The identification of key immunological effector pathways that amplify neuropathic features should lead to realistic possibilities for translatable therapeutic interventions using existing immunomodulators. Moreover, evidence emerges that neuroinflammation is not only able to modify primary neural damage-related symptoms but also may lead to unexpected clinical outcomes such as neuropsychiatric syndromes.

SCRG1 suppresses LPS-induced CCL22 production through ERK1/2 activation in mouse macrophage Raw264.7 cells

Recently, we identified the scrapie responsive gene 1 (SCRG1) secreted from mesenchymal stem cells (MSCs) and its receptor bone marrow stromal cell antigen 1 (BST1) as positive regulators of stem cell qualities such as self-renewal, migration abilities, and osteogenic differentiation potential. Here, we examined the effect of the paracrine activity of SCRG1 in macrophages. The mouse macrophage-like cell line Raw264.7 expressed BST1/β1 or BST1/β2 integrin as possible SCRG1 receptors. Unexpectedly, recombinant SCRG1 did not enhance cell proliferation, migration, or adhesion in these macrophages. However, further examination of the effect of SCRG1 in Raw264.7 cells did reveal a potent anti-inflammatory effect whereby SCRG1 suppressed LPS-induced CCL22 production. SCRG1 also induced the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in these cells and, moreover, a mitogen-activated protein kinase (MAPK)/ERK kinase inhibitor U0126 significantly suppressed the effect of SCRG1 on LPS-induced chemokine CCL22 production. Taken together, these data indicate that SCRG1 signals through the MAPK pathway and suppresses the LPS signaling pathway. CCL22 is generally known to be chemotactic for monocytes, dendritic cells, natural killer cells and chronically activated T lymphocytes, suggesting that MSC-derived SCRG1 may block infiltration of these cells. A mechanism is proposed by which MSCs play their immunosuppressive role through suppressing chemokine expression in monocyte/macrophage lineage cells.

A Functional and Neuropathological Testing Paradigm Reveals New Disability-Based Parameters and Histological Features for P0180-190-Induced Experimental Autoimmune Neuritis in C57BL/6 Mice

We assessed novel disability-based parameters and neuropathological features of the P0180-190 peptide-induced model of experimental autoimmune neuritis (EAN) in C57BL/6 mice. We show that functional assessments such as running capacity provide a more sensitive method for detecting alterations in disease severity than a classical clinical scoring paradigm. We performed detailed ultrastructural analysis and show for the first time that tomaculous neuropathy is a neuropathological feature of this disease model. In addition, we demonstrate that ultrastructural assessments of myelin pathology are sufficiently sensitive to detect significant differences in both mean G-ratio and mean axon diameter between mice with EAN induced with different doses of pertussis toxin. In summary, we have established a comprehensive assessment paradigm for discriminating variations in disease severity and the extent of myelin pathology in this model. Our findings indicate that this model is a powerful tool to study the pathogenesis of human peripheral demyelinating neuropathies and that this assessment paradigm could be used to determine the efficacy of potential therapies that aim to promote myelin repair and protect against nerve damage in autoimmune neuritides.

Enhancement of Anti-Inflammatory and Osteogenic Abilities of Mesenchymal Stem Cells via Cell-to-Cell Adhesion to Periodontal Ligament-Derived Fibroblasts

Mesenchymal stem cells (MSCs) are involved in anti-inflammatory events and tissue repair; these functions are activated by their migration or homing to inflammatory tissues in response to various chemokines. However, the mechanism by which MSCs interact with other cell types in inflammatory tissue remains unclear. We investigated the role of periodontal ligament fibroblasts (PDL-Fs) in regulating the anti-inflammatory and osteogenic abilities of bone marrow-derived- (BM-) MSCs. The expression of monocyte chemotactic protein- (MCP-)1 was significantly enhanced by stimulation of PDL-Fs with inflammatory cytokines. MCP-1 induced the migratory ability of BM-MSCs but not PDL-Fs. Expression levels of anti-inflammatory and inflammatory cytokines were increased and decreased, respectively, by direct-contact coculture between MSCs and PDL-Fs. In addition, the direct-contact coculture enhanced the expression of MSC markers that play important roles in the self-renewal and maintenance of multipotency of MSCs, which in turn induced the osteogenic ability of the cells. These results suggest that MCP-1 induces the migration and homing of BM-MSCs into the PDL inflammatory tissue. The subsequent adherence of MSCs to PDL-Fs plays an immunomodulatory role to terminate inflammation during wound healing and upregulates the expression stem cell markers to enhance the stemness of MSCs, thereby facilitating bone formation in damaged PDL tissue.

Review: Multiple system atrophy: emerging targets for interventional therapies

Multiple system atrophy (MSA) is a fatal orphan neurodegenerative disorder that manifests with rapidly progressive autonomic and motor dysfunction. The disease is characterized by the accumulation of α-synuclein fibrils in oligodendrocytes that form glial cytoplasmic inclusions, a neuropathological hallmark and central player in the pathogenesis of MSA. Here, we summarize the current knowledge on the etiopathogenesis and neuropathology of MSA. We discuss the role of α-synuclein pathology, microglial activation, oligodendroglial dysfunction and putative cell death mechanisms as candidate therapeutic targets in MSA.

Effect of systemic transplantation of bone marrow-derived mesenchymal stem cells on neuropathology markers in APP/PS1 Alzheimer mice

AIMS

Mesenchymal stem cells (MSC) have recently attracted interest as a potential basis for a cell-based therapy of AD. We investigated the putative immune-modulatory effects in neuroinflammation of systemic transplantation of MSC into APP/PS1 transgenic mice.

METHODS

10⁶ MSC were injected into APP/PS1 mice via the tail vein and histological analysis was performed for microglia and amyloid (pE3-Aβ) plaque numbers, glial distribution and pE3-Aβ plaque size. In addition, a biochemical analysis by qPCR for pro-inflammatory, chemoattractant and neurotrophic factors was performed.

RESULTS

MSC are associated with pE3-Aβ plaques. The effects of transplantation on microglia-associated pathology could be observed after 28 days. Animals showed a reduction in microglial numbers in the cortex and in microglia size. Gene expression was reduced for TNF-α, IL-6, MCP-1, and for NGF, in MSC recipients. Also, we investigated for the first time and found no changes in expression of IL-10, CCR5, BDNF, VEGF and IFNγ. PTGER2 expression levels were increased in the hippocampus but were reduced in the cortex of MSC recipients. While there were no transplant-related changes in pE3-Aβ plaque numbers, a reduction in the size of pE3-Aβ plaques was observed in the hippocampus of transplant recipients.

CONCLUSION

This is the first study to show reduction in pE3-Aβ plaque size. pE3-Aβ plaques have gained attention as potential key participants in AD due to their increased aggregation propensity, the possibility for the initial seeding event, resistance against degradation and neurotoxicity. These findings support the hypothesis that MSC-transplants may affect AD pathology via an immune-modulatory function that includes an effect on microglial cells.

Animal modeling an oligodendrogliopathy--multiple system atrophy

Multiple system atrophy (MSA) is a rare, yet rapidly-progressive neurodegenerative disease that presents clinically with autonomic failure in combination with parkinsonism or cerebellar ataxia. The definitive neuropathology differentiating MSA from Lewy body diseases is the presence of α-synuclein aggregates in oligodendrocytes (called glial cytoplasmic inclusion or GCI) rather than the fibrillar aggregates in neurons (called Lewy bodies). This makes the pathological pathway(s) in MSA unique in that oligodendrocytes are involved rather than predominantly neurons, as is most other neurodegenerative disorders. MSA is therefore regarded as an oligodendrogliopathy. The etiology of MSA is unknown. No definitive risk factors have been identified, although α-synuclein and other genes have been variably linked to MSA risk. Utilization of postmortem brain tissues has greatly advanced our understanding of GCI pathology and the subsequent neurodegeneration. However, extrapolating the early pathogenesis of MSA from such resource has been difficult and limiting. In recent years, cell and animal models developed for MSA have been instrumental in delineating unique MSA pathological pathways, as well as aiding in clinical phenotyping. The purpose of this review is to bring together and discuss various animal models that have been developed for MSA and how they have advanced our understanding of MSA pathogenesis, particularly the dynamics of α-synuclein aggregation. This review will also discuss how animal models have been used to explore potential therapeutic avenues for MSA, and future directions of MSA modeling.

Serum Lymphocyte-Associated Cytokine Concentrations Change More Rapidly over Time in Multiple System Atrophy Compared to Parkinson Disease

OBJECTIVE

Chronic inflammatory processes contribute to the eventual death of motor neurons and the development of symptoms in both idiopathic Parkinson disease (PD) and multiple system atrophy (MSA). Given the faster rate of progression and more severe symptoms associated with MSA, we hypothesized that markers of inflammation would be more evident in the peripheral blood of MSA than PD patients, and that evidence of this inflammation might assist early diagnosis of MSA versus PD.

METHODS

We performed multiplex analysis to determine the concentrations of 37 immune-associated cytokines and chemokines isolated from the plasma of patients with PD (n = 25) and MSA (n = 14) and compared our results to those of age-matched controls (n = 15). We then applied a mixed-effect multiple regression model to determine if the concentration of cytokines in the plasma of patients with PD and MSA changed significantly over time.

RESULTS

Patients with MSA had a trend towards overall lower levels of immune-associated cytokines, while serum cytokine levels were increased in patients with PD. Statistically adjusted comparisons of overall changes in cytokine concentrations between the PD and MSA groups revealed higher concentrations of T-cell-associated cytokines TNFβ and IL-7 in PD. Comparison of samples taken over time revealed significantly faster rates of change in 4 different cytokine concentrations (IL-4, IL-15, IL-2, and IL-9) in patients with MSA versus patients with PD.

CONCLUSIONS

Our results suggest that single measurements of plasma concentrations of inflammation-associated cytokines cannot be used to distinguish disease states. However, measurements made over time may correlate with pathogenesis. The significant changes in T-cell-associated cytokines may shed light on immune mechanisms that contribute to PD and MSA disease progression.

Neuroinflammation in Multiple System Atrophy: Response to and Cause of α-Synuclein Aggregation

Multiple system atrophy (MSA) is a progressive neurodegenerative disease presenting with combinations of autonomic dysfunction, parkinsonism, cerebellar ataxia and/or pyramidal signs. Oligodendroglial cytoplasmic inclusions (GCIs) rich in α-synuclein (α-syn) constitute the disease hallmark, accompanied by neuronal loss and activation of glial cells which indicate neuroinflammation. Recent studies demonstrate that α-syn may be released from degenerating neurons to mediate formation of abnormal inclusion bodies and to induce neuroinflammation which, interestingly, might also favor the formation of intracellular α-syn aggregates as a consequence of cytokine release and the shift to a pro-inflammatory environment. Here, we critically review the relationships between α-syn and astrocytic and microglial activation in MSA to explore the potential of therapeutics which target neuroinflammation.

Adult autologous mesenchymal stem cells for the treatment of suspected non-infectious inflammatory diseases of the canine central nervous system: safety, feasibility and preliminary clinical findings

Background

Non-infectious inflammatory diseases of the canine central nervous system (CNS) are common idiopathic disorders grouped under the term meningoencephalomyelitis of unknown origin (MUO). Ante mortem diagnosis is achieved via assessment of clinical signs, magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) analysis, but the definitive diagnosis needs histopathological examination. MUO are mostly considered as autoimmune CNS disorders, so that suppressing the immune reaction is the best management method for patients. Mesenchymal stem cells (MSCs) are under investigation to treat autoimmune and degenerative disorders due to their immunomodulatory and regenerative properties. This study aims to verify the safety, feasibility, and efficacy of MSCs treatment in canine idiopathic autoimmune inflammatory disorders of the CNS.

Methods

Eight dogs presented with acute onset and rapid progression of multifocal neurological signs were selected to the study. In all patients’ physical and neurological examinations, MRI and CSF analyses were performed. Clinical diagnosis in all cases was MUO. All selected dogs responded initially to immunosuppressive drugs (prednisone and a combination of prednisolone and cytosine arabinoside) but developed undesirable side effects. For all eight dogs, the owners considered euthanasia but accepted cell therapy as a last possibility. Autologous bone marrow MSCs (BMMSCs), isolated, cultured, and expanded, were administered by intrathecal (IT) injection in the cisterna magna intravenously (IV) and by intra-arterial (IA) injection in the right carotid artery. Adverse effects and clinical response were monitored for 6 months up to 2-year follow-up.

Results

The use of autologous BMMSCs in dogs with MUO was safe for IT, IV, and IA injections. No major short- or long-term adverse effects were registered. All the dogs presented early improvement in their general and neurological conditions, with particular effect on cervical pain. The group of dogs treated by IT+IA administration showed a shorter time of reaction to therapy compared to the group treated by IT+IV administration.

Conclusions

MSCs treatment in dogs affected by MOU is safe and feasible. A larger group of dogs is needed to confirm these results as well as CNS histology in order to better understand the underlying mechanisms.

Mesenchymal Stem Cell Transplantation Promotes Neurogenesis and Ameliorates Autism Related Behaviors in BTBR Mice

Autism spectrum disorders (ASD) are characterized by social communication deficits, cognitive rigidity, and repetitive stereotyped behaviors. Mesenchymal stem cells (MSC) have a paracrine regenerative effect, and were speculated to be a potential therapy for ASD. The BTBR inbred mouse strain is a commonly used model of ASD as it demonstrates robust behavioral deficits consistent with the diagnostic criteria for ASD. BTBR mice also exhibit decreased brain-derived neurotrophic factor (BDNF) signaling and reduced hippocampal neurogenesis. In the current study, we evaluated the behavioral and molecular effects of intracerebroventricular MSC transplantation in BTBR mice. Transplantation of MSC resulted in a reduction of stereotypical behaviors, a decrease in cognitive rigidity and an improvement in social behavior. Tissue analysis revealed elevated BDNF protein levels in the hippocampus accompanied by increased hippocampal neurogenesis in the MSC-transplanted mice compared with sham treated mice. This might indicate a possible mechanism underpinning the behavioral improvement. Our study suggests a novel therapeutic approach which may be translatable to ASD patients in the future.

Intranasal Delivery of Bone Marrow Mesenchymal Stem Cells Improved Neurovascular Regeneration and Rescued Neuropsychiatric Deficits after Neonatal Stroke in Rats

Neonatal stroke is a major cause of mortality and long-term morbidity in infants and children. Currently, very limited therapeutic strategies are available to protect the developing brain against ischemic damage and promote brain repairs for pediatric patients. Moreover, children who experienced neonatal stroke often have developmental social behavior problems. Cellular therapy using bone marrow mesenchymal stem cells (BMSCs) has emerged as a regenerative therapy after stroke. In the present investigation, neonatal stroke of postnatal day 7 (P7) rat pups was treated with noninvasive and brain-specific intranasal delivery of BMSCs at 6 h and 3 days after stroke (1 × 106cells/animal). Prior to transplantation, BMSCs were subjected to hypoxic preconditioning to enhance their tolerance and regenerative properties. The effects on regenerative activities and stroke-induced sensorimotor and social behavioral deficits were specifically examined at P24 of juvenile age. The BMSC treatment significantly reduced infarct size and blood-brain barrier disruption, promoted angiogenesis, neurogenesis, neurovascular repair, and improved local cerebral blood flow in the ischemic cortex. BMSC-treated rats showed better sensorimotor and olfactory functional recovery than saline-treated animals, measured by the adhesive removal test and buried food finding test. In social behavioral tests, we observed functional and social behavioral deficits in P24 rats subjected to stroke at P7, while the BMSC treatment significantly improved the performance of stroke animals. Overall, intranasal BMSC transplantation after neonatal stroke shows neuroprotection and great potential as a regenerative therapy to enhance neurovascular regeneration and improve functional recovery observed at the juvenile stage of development.

Animal models of multiple system atrophy

Since their introduction in 1996, animal models of multiple system atrophy (MSA) have generated important insights into pathogenesis and interventional therapies. Toxin and genetic approaches have been used alone or in combination to replicate progressive motor and non-motor symptoms reflecting human neuropathology. Here, we review these developments and discuss the advantages and limitations of the MSA animal models, as well as their application in preclinical target validation.

Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha-synuclein in oligodendrocytes

Mice overexpressing human alpha‐synuclein in oligodendrocytes (MBP1‐α‐syn) recapitulate some key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice develop severe autonomic failure, which is a key feature of human MSA, remains unknown. We explored cardiovascular autonomic regulation using long‐term blood pressure (BP) radiotelemetry and pharmacological testing. We instrumented 12 MBP1‐α‐syn mice and 11 wild‐type mice aged 9 months for radiotelemetry. Animals were tested with atropine, metoprolol, clonidine, and trimethaphan at 9 and 12 months age. We applied spectral and cross‐spectral analysis to assess heart rate (HR) and BP variability. At 9 months of age daytime BP (transgenic: 101 ± 2 vs. wild type: 99 ± 2 mmHg) and HR (497 ± 11 vs. 505 ± 16 beats/min) were similar. Circadian BP and HR rhythms were maintained. Nighttime BP (109 ± 2 vs. 108 ± 2 mmHg) and HR (575 ± 15 vs. 569 ± 14 beats/min), mean arterial BP responses to trimethaphan (−21 ± 8 vs. −10 ± 5 mmHg, P = 0.240) and to clonidine (−8 ± 3 vs. −5 ± 2 mmHg, P = 0.314) were similar. HR responses to atropine (+159 ± 24 vs. +146 ± 22 beats/min), and to clonidine (−188 ± 21 vs. −163 ± 33 beats/min) did not differ between strains. Baroreflex sensitivity (4 ± 1 vs. 4 ± 1 msec/mmHg) and HR variability (total power, 84 ± 17 vs. 65 ± 21 msec²) were similar under resting conditions and during pharmacological testing. Repeated measurements at 12 months of age provided similar results. In mice, moderate overexpression of human alpha‐synuclein in oligodendrocytes is not sufficient to induce overt autonomic failure. Additional mechanisms may be required to express the autonomic failure phenotype including higher levels of expression or more advanced age.

Mice overexpressing human alpha‐synuclein in oligodendrocytes recapitulate key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice model MSA abnormalities in cardiovascular autonomic regulation is unknown. Therefore, we explored cardiovascular autonomic regulation using long‐term blood pressure radiotelemetry combined with detailed pharmacological testing in mice overexpressing moderate levels of human alpha‐synuclein under the control of the oligodendrocyte‐specific murine myelin basic protein promoter. The major finding was that the moderate overexpression of human alpha‐synuclein in oligodendrocytes was not sufficient to induce overt autonomic failure in this mouse model.

A safety study on intrathecal delivery of autologous mesenchymal stromal cells in rabbits directly supporting Phase I human trials

BACKGROUND

There are no effective treatments that slow the progression of neurodegenerative diseases. A major challenge of treatment in neurodegenerative diseases is appropriate delivery of pharmaceuticals into the cerebrospinal fluid (CSF) of affected individuals. Mesenchymal stromal cells (MSCs-either naïve or modified) are a promising therapy in neurodegenerative diseases and may be delivered directly into the CSF where they can reside for months. In this preclinical study, we evaluated the safety of intrathecal autologous MSCs in a rabbit model.

STUDY DESIGN AND METHODS

Autologous adipose-derived MSCs (or artificial CSF) were delivered intrathecally, either with single or with repeated injections into the foramen magnum of healthy rabbits and monitored for 4 and 12 weeks, respectively.

RESULTS

Rabbits tolerated injections well and no definitive MSC-related side effects were observed apart from three rabbits that had delayed death secondary to traumatic foramen magnum puncture. Functional assessments and body weights were equivalent between groups. Gross pathology and histology did not reveal any abnormalities or tumor growth. Complete blood count data were normal and there were no differences in CSF interleukin-6 levels in all groups tested.

CONCLUSION

Our data suggest that intrathecal delivery of autologous MSCs is safe in a rabbit model. Data from this study have supported two successful investigational new drug applications to the Food and Drug Administration, resulting in the initiation of two clinical trials using autologous MSCs in amyotrophic lateral sclerosis and multiple system atrophy.

Influence of intrathecal delivery of bone marrow-derived mesenchymal stem cells on spinal inflammation and pain hypersensitivity in a rat model of peripheral nerve injury

Background

Multipotent mesenchymal stem (stromal) cells (MSCs) have been credited with immunomodulative properties, supporting beneficial outcomes when transplanted into a variety of disease models involving inflammation. Potential mechanisms include the secretion of paracrine factors and the establishment of a neurotrophic microenvironment. To test the hypothesis that MSCs release soluble mediators that can attenuate local inflammation, we here analysed the influence of MSCs on the activation of microglia cells, as well as on inflammatory parameters and pain behaviour in a surgical rat model of neuropathic pain.

Methods

We focussed on an experimental model of partial sciatic nerve ligation (PSNL), characterised by a rapid and persistent inflammation in the dorsal lumbar spinal cord where sensory inputs from the sciatic nerve are processed. Via indwelling intrathecal catheters, MSCs were repetitively grafted into the intrathecal lumbar space. Animals were evaluated for mechanical and thermal hypersensitivity over a period of 21 days after PSNL. Afterwards, spinal cords were processed for immunohistochemical analysis of the microglial marker ionized calcium-binding adapter molecule 1 (Iba1) and quantification of inflammatory markers in ipsilateral dorsal horns. We hypothesised that injections on postsurgical days 2 to 4 would interfere with microglial activation, leading to a reduced production of pro-inflammatory cytokines and amelioration of pain behaviour.

Results

PSNL-induced mechanical allodynia or heat hyperalgesia were not influenced by MSC transplantation, and spinal cord inflammatory processes remained largely unaffected. Indeed, the early microglial response to PSNL characterised by increased Iba1 expression in the lumbar dorsal horn was not significantly altered and cytokine levels in the spinal cord at 21 days after surgery were similar to those found in vehicle-injected animals. Grafted MSCs were detected close to the pia mater, but were absent within the spinal cord parenchyma.

Conclusions

We conclude that intrathecal administration is not an appropriate route to deliver cells for treatment of acute spinal cord inflammation as it leads to entrapment of grafted cells within the pia mater. We propose that the early inflammatory response triggered by PSNL in the lumbar spinal cord failed to effectively recruit MSCs or was insufficient to disturb the tissue integrity so as to allow MSCs to penetrate the spinal cord parenchyma.

Novel therapeutic approaches in multiple system atrophy

Multiple system atrophy (MSA) is a sporadic, adult onset, relentlessly progressive neurodegenerative disease characterized by autonomic abnormalities associated with parkinsonism, cerebellar dysfunction, pyramidal signs, or combinations thereof. Treatments that can halt or reverse the progression of MSA have not yet been identified. MSA is neuropathologically defined by the presence of α-synuclein-containing inclusions, particularly in the cytoplasm of oligodendrocytes (glial cytoplasmic inclusions, GCIs), which are associated with neurodegeneration. The mechanisms by which oligodendrocytic α-synuclein inclusions cause neuronal death in MSA are not completely understood. The MSA neurodegenerative process likely comprises cell-to-cell transmission of α-synuclein in a prion-like manner, α-synuclein aggregation, increased oxidative stress, abnormal expression of tubulin proteins, decreased expression of neurotrophic factors, excitotoxicity and microglial activation, and neuroinflammation. In an attempt to block each of these pathogenic mechanisms, several pharmacologic approaches have been tried and shown to exert neuroprotective effects in transgenic mouse or cellular models of MSA. These include sertraline, paroxetine, and lithium, which hamper arrival of α-synuclein to oligodendroglia; rifampicin, lithium, and non-steroidal anti-inflammatory drugs, which inhibit α-synuclein aggregation in oligodendrocytes; riluzole, rasagiline, fluoxetine and mesenchymal stem cells, which exert neuroprotective actions; and minocycline and intravenous immunoglobulins, which reduce neuroinflammation and microglial activation. These and other potential therapeutic strategies for MSA are summarized in this review.

Brain mesenchymal stem cells: The other stem cells of the brain?

Multipotent mesenchymal stromal cells (MSC), have the potential to differentiate into cells of the mesenchymal lineage and have non-progenitor functions including immunomodulation. The demonstration that MSCs are perivascular cells found in almost all adult tissues raises fascinating perspectives on their role in tissue maintenance and repair. However, some controversies about the physiological role of the perivascular MSCs residing outside the bone marrow and on their therapeutic potential in regenerative medicine exist. In brain, perivascular MSCs like pericytes and adventitial cells, could constitute another stem cell population distinct to the neural stem cell pool. The demonstration of the neuronal potential of MSCs requires stringent criteria including morphological changes, the demonstration of neural biomarkers expression, electrophysiological recordings, and the absence of cell fusion. The recent finding that brain cancer stem cells can transdifferentiate into pericytes is another facet of the plasticity of these cells. It suggests that the perversion of the stem cell potential of pericytes might play an even unsuspected role in cancer formation and tumor progression.