Immunomodulatory Effects of Exercise in Experimental Multiple Sclerosis

Factors influencing adherence to Physical Exercise in patients with multiple sclerosis: a systematic review focusing on Exercise over General Physical Activity

BACKGROUND

While the barriers and facilitators of physical activity adherence are well-defined, there is a limited number of studies focusing specifically on exercise adherence, which is crucial to identify in patients with multiple sclerosis (MS) due to its known disease-modifying effect.

OBJECTIVE

To investigate the factors affecting adherence to physical exercise in MS patients.

METHODS

Literature search was conducted in PubMed, Cochrane, Web of Science, and Scopus electronic databases up to the current date. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS) for quantitative studies and the McMaster Critical Appraisal Tool for qualitative studies, with evidence synthesis conducted using the Modified Bakker Scale.

RESULTS

The systematic review incorporated thirteen studies, consisting of seven qualitative and six quantitative ones. These studies' methodological quality was high; 12 were high, and the other was medium (unclear). In all reviewed studies, the primary patient-related and environmental barriers with high levels of evidence regarding exercise adherence included fatigue (38%), false beliefs (18%), cost (18%), and lack of time (15%). Barriers identified in very few studies included cognitive problems (3%), bladder-bowel problems (3%), and family support and advice (3%), indicating a necessity for further research to reveal their impact on exercise adherence.

CONCLUSION

The scarcity of studies on exercise barriers in MS is partly due to the absence of reliable assessment methods for evaluating exercise adherence, along with the prevalent emphasis on physical activity. Future research should prioritize the development of adherence scales tailored to physical exercise and shifting focus towards less explored barriers.

Baseline Inflammation but not Exercise Modality Impacts Exercise-induced Kynurenine Pathway Modulation in Persons With Multiple Sclerosis: Secondary Results From a Randomized Controlled Trial

Background

The kynurenine pathway (KP) is an important hub in neuroimmune crosstalk that is dysregulated in persons with multiple sclerosis (pwMS) and modulated by exercise in a modality-specific manner.

Objectives

To compare changes in the KP metabolite profile of pwMS (1) following combined treatments including either high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) during a 3-week multimodal rehabilitation, (2) to evaluate exercise response in relation to baseline systemic inflammation, and (3) to investigate associations of kynurenines with physical capacity and clinical outcomes.

Methods

For this secondary analysis of a randomized controlled trial, serum concentrations of kynurenines at baseline and after 3 weeks were determined using targeted metabolomics (LC-MS/MS). Exercise-induced changes in the KP metabolite profile according to treatment and baseline systemic inflammation (neutrophil-to-lymphocyte ratio (NLR) <3.12 versus ⩾3.12) were investigated using covariance analyses.

Results

Regardless of treatment, concentrations of tryptophan and most kynurenines decreased over time. Quinolinic acid concentration increased (p < .001). Participants with low and high NLR revealed differential exercise-induced changes in concentrations of kynurenines and NLR. The systemic inflammation markers neopterin (p = .015) and NLR (p < .001) decreased in the whole group and in participants with high NLR, respectively.

Conclusions

Combined treatments including HIIT or MICT do not differentially modulate the KP metabolite profile, with both reducing concentrations of most kynurenines. Baseline systemic inflammation may impact exercise-induced changes in the KP metabolite profile and anti-inflammatory effects of exercise in pwMS.

Trial registration

clinicaltrials.gov (identifier: NCT04356248).

The relevance of BDNF for neuroprotection and neuroplasticity in multiple sclerosis

Background

Neuroplasticity as a mechanism to overcome central nervous system injury resulting from different neurological diseases has gained increasing attention in recent years. However, deficiency of these repair mechanisms leads to the accumulation of neuronal damage and therefore long-term disability. To date, the mechanisms by which remyelination occurs and why the extent of remyelination differs interindividually between multiple sclerosis patients regardless of the disease course are unclear. A member of the neurotrophins family, the brain-derived neurotrophic factor (BDNF) has received particular attention in this context as it is thought to play a central role in remyelination and thus neuroplasticity, neuroprotection, and memory.

Objective

To analyse the current literature regarding BDNF in different areas of multiple sclerosis and to provide an overview of the current state of knowledge in this field.

Conclusion

To date, studies assessing the role of BDNF in patients with multiple sclerosis remain inconclusive. However, there is emerging evidence for a beneficial effect of BDNF in multiple sclerosis, as studies reporting positive effects on clinical as well as MRI characteristics outweighed studies assuming detrimental effects of BDNF. Furthermore, studies regarding the Val66Met polymorphism have not conclusively determined whether this is a protective or harmful factor in multiple sclerosis, but again most studies hypothesized a protective effect through modulation of BDNF secretion and anti-inflammatory effects with different effects in healthy controls and patients with multiple sclerosis, possibly due to the pro-inflammatory milieu in patients with multiple sclerosis. Further studies with larger cohorts and longitudinal follow-ups are needed to improve our understanding of the effects of BDNF in the central nervous system, especially in the context of multiple sclerosis.

Decreased exercise-induced natural killer cell redistribution in multiple sclerosis

BACKGROUND

Exercise may have beneficial effects in MS, remaining controversial its possible disease-modifying effects and which mechanisms might be involved. We evaluated whether exercise-induced lymphocyte redistribution differ in MS patients as compared to controls.

METHODS

Exercise was assessed in 12 relapsing-remitting MS patients and 11 controls in a cycle ergometer, obtaining blood samples before exercise, at maximal exercise capacity (T1), and after resting (T2). Peripheral lymphocytes were evaluated by flow cytometry, assessing chemokine receptor expression to study cell trafficking properties.

RESULTS

Lymphocyte subsets in all cases increased after exercise and decreased at resting. However, total natural killer (NK) cells in patients as compared to controls had a lower exercise-induced redeployment at T1 (696 ± 581 cells/µL vs.1502 ± 641 cells/µL, p < 0.01). Evaluating NK cell subsets, CD56bright NK cells numbers decreased in peripheral blood in MS patients after resting (T2), contrasting with values remaining above baseline in healthy controls. NK cells mobilized after exercise at T1 in controls, as compared to patients, had a higher CX3CR1 expression (1402 ± 564/µL vs. 615 ± 548 cell//µL, p < 0.01).

CONCLUSION

Exercise-induced redeployment of NK cells may be reduced in MS patients, as well as their migration capabilities, pointing to potential immunological mechanisms to be enhanced by exercise training programs.

Empowering Minds and Bodies: The Impact of Exercise on Multiple Sclerosis and Cognitive Health

Multiple sclerosis (MS) is a global health concern affecting around 2.6 million people. It is characterised by neural inflammation, myelin breakdown and cognitive decline. Cognitive impairment, especially reduced cognitive processing speed (CPS), which affects up to 67% of MS patients and frequently manifests before mobility concerns, is one of the disease's most serious side effects. Effective adaptation and the application of cognitive rehabilitation treatments depend on the early diagnosis of cognitive impairment. Although pharmaceutical therapies have some drawbacks, endurance training has become a promising alternative. Intensity-controlled endurance exercise has the ability to delay the onset of MS symptoms and enhance cognitive function. Exercise has also been shown to have neuroprotective effects in a number of neurological disorders, including MS, Parkinson's disease and stroke. This includes both aerobic and resistance training. A mix of aerobic exercise and weight training has shown promise, especially for people with mild cognitive impairment, but according to recent studies any amount of physical activity is beneficial to cognitive performance. In conclusion, this in-depth analysis highlights the crucial part endurance exercise plays in treating MS-related cognitive impairment. It improves not only neurological health in general but also cognitive performance. Exercise can help control MS in a way that dramatically improves quality of life and well-being.

Preventive exercise and physical rehabilitation promote long-term potentiation-like plasticity expression in patients with multiple sclerosis

BACKGROUND AND PURPOSE

Loss of long-term potentiation (LTP) expression has been associated with a worse disease course in relapsing-remitting multiple sclerosis (RR-MS) and represents a pathophysiological hallmark of progressive multiple sclerosis (PMS). Exercise and physical rehabilitation are the most prominent therapeutic approaches to promote synaptic plasticity. We aimed to explore whether physical exercise is able to improve the expression of LTP-like plasticity in patients with multiple sclerosis (MS).

METHODS

In 46 newly diagnosed RR-MS patients, we explored the impact of preventive exercise on LTP-like plasticity as assessed by intermittent theta-burst stimulation. Patients were divided into sedentary or active, based on physical activity performed during the 6 months prior to diagnosis. Furthermore, in 18 patients with PMS, we evaluated the impact of an 8-week inpatient neurorehabilitation program on clinical scores and LTP-like plasticity explored using paired associative stimulation (PAS). Synaptic plasticity expression was compared in patients and healthy subjects.

RESULTS

Reduced LTP expression was found in RR-MS patients compared with controls. Exercising RR-MS patients showed a greater amount of LTP expression compared with sedentary patients. In PMS patients, LTP expression was reduced compared with controls and increased after 8 weeks of rehabilitation. In this group of patients, LTP magnitude at baseline predicted the improvement in hand dexterity.

CONCLUSIONS

Both preventive exercise and physical rehabilitation may enhance the expression of LTP-like synaptic plasticity in MS, with potential beneficial effects on disability accumulation.

The MoxFo initiative-Mechanisms of action: Biomarkers in multiple sclerosis exercise studies

BACKGROUND

As exercise exerts neurobiological and immunomodulatory effects, it might also act as a disease-modifying intervention in MS. However, a clear mechanistic link between exercise and disease-modifying effects in MS has yet to be established.

OBJECTIVE

Establish recommendations for future mechanistic exercise studies in MS.

METHODS

In regular meetings, members of the mechanisms of action group within the MoXFo (Moving eXercise research Forward in MS) initiative evaluated gaps of knowledge and discussed unmet needs in mechanistic MS research.

RESULTS

We concluded that biomarkers assessed in translational studies in humans and animals are essential to decipher the underlying mechanisms of exercise in MS. Consequently, we defined clear definitions of different types of biomarkers examined in MS exercise studies and operationalized their use to align with the research question and optimal testing time points. Furthermore, we provide key considerations to improve the rigor of translational studies and defined minimal reporting criteria for animal studies.

CONCLUSION

The resulting recommendations are intended to improve the quality of future mechanistic exercise studies in MS and consequently lead to a better understanding of therapeutic approaches.

Admission and discharge profiles of people with MS accessing in-patient rehabilitation in Canada

BACKGROUND

Rehabilitation is the mainstay of management for people with disabilities of neurological origin to maximize function and reduce disability. Access to in-patient rehabilitation is usually reserved for people after crises or those who are discharged from acute care such as in stroke or trauma. Access to people with Multiple Sclerosis (MS) differs across countries and unknown for Canada. With the progression of MS, quality of life (QOL) becomes more closely coupled with independence and hence timely access to rehabilitation is important. The objectives of this paper are (i) to characterize the disability profiles of people with MS admitted to in-patient rehabilitation in Canada; and (ii) to estimate the extent to which disability profiles differ from admission to discharge.

METHODS

A longitudinal study of a rehabilitation admission-to-discharge cohort of 3500 people with MS was conducting using latent class analysis on the five Functional Independence Measure (FIM) subscales for Self-care, Transfers, Locomotion, Bladder/Bowel, and Cognition. The extent to which age, sex, and calendar time was associated with latent class membership, at both admission and discharge, was estimated using ordinal logistic regression, and proportional odds model was calculated for each age and sex.

RESULTS

At admission five classes were identified. The two most prevalent classes included people with total or moderate dependency in all FIM subscales except cognition (n = 1205 and n = 1099). The third most common was dependent in ambulation only (n = 523), followed by dependence in ambulation with varying degree of limitation in self-care and transfers (n = 465, and n = 208). At discharge four classes were identified with the largest class comprising of people dependent in ambulation and to a lesser degree in transfers (n = 1010). The second most prevalent class was no dependency (n = 946), followed by two classes with varying dependency in all subscales but cognition (n = 678 and n = 771).

CONCLUSION

Overall 62.3% of admissions transitioned to a more functional class by discharge. By discharge 28% of the population was characterized by no dependencies; however, 23% remained with dependencies in all areas. Those in the most dependent classes showed the greatest probability of transitioning to a better class at discharge highlighting the importance of reserving scarce rehabilitation services to those with more disability.

Multiple sclerosis and exercise-A disease-modifying intervention of mice or men?

Research suggests that physical exercise can promote an anti-inflammatory and neuroprotective state. If so, increasing or optimizing exercise could be considered a 'disease-modifying intervention' in neuroinflammatory diseases, such as multiple sclerosis (MS). Exercise intervention studies conducted in animal models of MS are promising. Various aerobic and strength training regimes have been shown to delay disease onset and to reduce both the clinical and pathological disease severity in mice. However, fundamental differences between the physiology of animals and humans, the disease states studied, and the timing of exercise intervention are significant. In animal models of MS, most exercise interventions begin before disease initiation and before any clinical sign of disease. In contrast, studies in humans recruit participants on average nearly a decade after diagnosis and often once disability is established. If, as is thought to be the case for disease-modifying treatments, the immunomodulatory effect of exercise decreases with advancing disease duration, current studies may therefore fail to detect the true disease-modifying potential. Clinical studies in early disease cohorts are needed to determine the role of exercise as a disease-modifying intervention for people with MS.

Influence of exercise on quantity and deformability of immune cells in multiple sclerosis

Objective

The study aimed to investigate the effect of exercise on immune cell count and cell mechanical properties in people with multiple sclerosis (pwMS) on different disease-modifying treatments (DMT) vs. healthy controls (HCs).

Methods

A cohort of 16 HCs and 45 pwMS, including patients with lymphopenia (alemtuzumab and fingolimod) as well as increased lymphocyte counts (natalizumab), was evaluated for exercise-mediated effects on immune cell counts and lymphocyte deformability. As exercise paradigms, climbing stairs at normal speed or as fast as possible and cycling were used, while blood samples were collected before, immediately, and 20 as well as 60 min post-exercise. Immune cell subtypes and lymphocyte deformability were analyzed using multicolor flow cytometry and real-time deformability cytometry.

Results

An increase in lymphocytes and selected subsets was observed following exercise in HCs and all pwMS on different DMTs. Patients with lymphopenia exhibited an increase in absolute lymphocyte counts and immune cell subsets till just below or into the reference range. An increase above the upper limit of the reference range was detected in patients on natalizumab. Exercise-induced alterations were observable even in low and more pronounced in high-intensity physical activities. Lymphocyte deformability was found to be only mildly affected by the investigated exercise regimes.

Conclusion

People with multiple sclerosis (PwMS) treated with alemtuzumab, fingolimod, and natalizumab respond to acute exercise with a comparable temporal pattern characterized by the increase of immune cell subsets as HCs. The magnitude of response is influenced by exercise intensity. Exercise-mediated effects should be considered when interpreting laboratory values in patients on immunomodulatory therapy. The impact of exercise on biophysical properties should be further elucidated.

Testosterone treatment combined with exercise to improve muscle strength, physical function and quality of life in men affected by inclusion body myositis: A randomised, double-blind, placebo-controlled, crossover trial

INTRODUCTION

Inclusion body myositis (IBM) is the most commonly acquired skeletal muscle disease of older adults involving both autoimmune attack and muscle degeneration. As exercise training can improve outcomes in IBM, this study assessed whether a combination of testosterone supplementation and exercise training would improve muscle strength, physical function and quality of life in men affected by IBM, more than exercise alone.

METHODS

This pilot study was a single site randomised, double-blind, placebo-controlled, crossover study. Testosterone (exercise and testosterone cream) and placebo (exercise and placebo cream) were each delivered for 12 weeks, with a two-week wash-out between the two periods. The primary outcome measure was improvement in quadriceps isokinetic muscle strength. Secondary outcomes included assessment of isokinetic peak flexion force, walk capacity and patient reported outcomes, and other tests, comparing results between the placebo and testosterone arms. A 12-month Open Label Extension (OLE) was offered using the same outcome measures collected at 6 and 12-months.

RESULTS

14 men completed the trial. There were no significant improvements in quadriceps extension strength or lean body mass, nor any of the secondary outcomes. Improvement in the RAND Short Form 36 patient reported outcome questionnaire 'emotional wellbeing' sub-category was reported during the testosterone arm compared to the placebo arm (mean difference [95% CI]: 6.0 points, [95% CI 1.7,10.3]). The OLE demonstrated relative disease stability over the 12-month period but with a higher number of testosterone-related adverse events.

CONCLUSIONS

Adding testosterone supplementation to exercise training did not significantly improve muscle strength or physical function over a 12-week intervention period, compared to exercise alone. However, the combination improved emotional well-being over this period, and relative stabilisation of disease was found during the 12-month OLE. A longer duration trial involving a larger group of participants is warranted.

Advances in Neurodegenerative Diseases

Neurological disorders are the leading cause of physical and cognitive disability across the globe, currently affecting approximately 15% of the worldwide population [...].

Neurorehabilitation in Multiple Sclerosis-A Review of Present Approaches and Future Considerations

Multiple sclerosis is an increasingly prevalent disease, representing the leading cause of non-traumatic neurological disease in Europe and North America. The most common symptoms include gait deficits, balance and coordination impairments, fatigue, spasticity, dysphagia and an overactive bladder. Neurorehabilitation therapeutic approaches aim to alleviate symptoms and improve the quality of life through promoting positive immunological transformations and neuroplasticity. The purpose of this study is to evaluate the current treatments for the most debilitating symptoms in multiple sclerosis, identify areas for future improvement, and provide a reference guide for practitioners in the field. It analyzes the most cited procedures currently in use for the management of a number of symptoms affecting the majority of patients with multiple sclerosis, from different training routines to cognitive rehabilitation and therapies using physical agents, such as electrostimulation, hydrotherapy, cryotherapy and electromagnetic fields. Furthermore, it investigates the quality of evidence for the aforementioned therapies and the different tests applied in practice to assess their utility. Lastly, the study looks at potential future candidates for the treatment and evaluation of patients with multiple sclerosis and the supposed benefits they could bring in clinical settings.

Preventive exercise attenuates IL-2-driven mood disorders in multiple sclerosis

BACKGROUND

Elevated levels of specific proinflammatory molecules in the cerebrospinal fluid (CSF) have been associated with disability progression, enhanced neurodegeneration and higher incidence of mood disorders in people with multiple sclerosis (MS). Studies in animal models of MS suggest that preventive exercise may play an immunomodulatory activity, with beneficial effects on both motor deficits and behavioral alterations. Here we explored the impact of lifestyle physical activity on clinical presentation and associated central inflammation in a large group of newly diagnosed patients with MS. Furthermore, we addressed the causal link between exercise-mediated immunomodulation and mood symptoms in the animal setting.

METHODS

A cross-sectional study was conducted on 235 relapsing-remitting MS patients at the time of the diagnosis. Patients were divided into 3 groups ("sedentary", "lifestyle physical activity" and "exercise") according to the level of physical activity in the six months preceding the evaluation. Patients underwent clinical, neuropsychological and psychiatric evaluation, magnetic resonance imaging and lumbar puncture for diagnostic purposes. The CSF levels of proinflammatory and anti-inflammatory cytokines were analyzed and compared with a group of 80 individuals with non-inflammatory and non-degenerative diseases. Behavioral and electrophysiological studies were carried out in control mice receiving intracerebral injection of IL-2 or vehicle. Behavior was also assessed in mice with experimental autoimmune encephalomyelitis (EAE), animal model of MS, reared in standard (sedentary group) or running wheel-equipped (exercise group) cages.

RESULTS

In exercising MS patients, depression and anxiety were reduced compared to sedentary patients. The CSF levels of the interleukin-2 and 6 (IL-2, IL-6) were increased in MS patients compared with control individuals. In MS subjects exercise was associated with normalized CSF levels of IL-2. In EAE mice exercise started before disease onset reduced both behavioral alterations and striatal IL-2 expression. Notably, a causal role of IL-2 in mood disorders was shown. IL-2 administration in control healthy mice induced anxious- and depressive-like behaviors and impaired type-1 cannabinoid (CB1) receptor-mediated neurotransmission at GABAergic synapses, mimicking EAE-induced synaptic dysfunction.

CONCLUSIONS

Our results indicate an immunomodulatory effect of exercise in MS patients, associated with reduced CSF expression of IL-2, which might result in reduced mood disorders. These data suggest that exercise in the early stages may act as a disease-modifying therapy in MS although further longitudinal studies are needed to clarify this issue.

Multimodal Benefits of Exercise in Patients With Multiple Sclerosis and COVID-19

Multiple sclerosis (MS) is a demyelinating disease characterized by plaque formation and neuroinflammation. The plaques can present in various locations, causing a variety of clinical symptoms in patients with MS. Coronavirus disease-2019 (COVID-19) is also associated with systemic inflammation and a cytokine storm which can cause plaque formation in several areas of the brain. These concurring events could exacerbate the disease burden of MS. We review the neuro-invasive properties of SARS-CoV-2 and the possible pathways for the entry of the virus into the central nervous system (CNS). Complications due to this viral infection are similar to those occurring in patients with MS. Conditions related to MS which make patients more susceptible to viral infection include inflammatory status, blood-brain barrier (BBB) permeability, function of CNS cells, and plaque formation. There are also psychoneurological and mood disorders associated with both MS and COVID-19 infections. Finally, we discuss the effects of exercise on peripheral and central inflammation, BBB integrity, glia and neural cells, and remyelination. We conclude that moderate exercise training prior or after infection with SARS-CoV-2 can produce health benefits in patients with MS patients, including reduced mortality and improved physical and mental health of patients with MS.

Investigating the potential disease-modifying and neuroprotective efficacy of exercise therapy early in the disease course of multiple sclerosis: The Early Multiple Sclerosis Exercise Study (EMSES)

BACKGROUND

Potential supplemental disease-modifying and neuroprotective treatment strategies are warranted in multiple sclerosis (MS). Exercise is a promising non-pharmacological approach, and an uninvestigated 'window of opportunity' exists early in the disease course.

OBJECTIVE

To investigate the effect of early exercise on relapse rate, global brain atrophy and secondary magnetic resonance imaging (MRI) outcomes.

METHODS

This randomized controlled trial (n = 84, disease duration <2 years) included 48 weeks of supervised aerobic exercise or control condition. Population-based control data (Danish MS Registry) was included (n = 850, disease duration <2 years). Relapse rates were obtained from medical records, and patients underwent structural and diffusion-kurtosis MRI at baseline, 24 and 48 weeks.

RESULTS

No between-group differences were observed for primary outcomes, relapse rate (incidence-rate-ratio exercise relative to control: (0.49 (0.15; 1.66), p = 0.25) and global brain atrophy rate (-0.04 (-0.48; 0.40)%, p = 0.87), or secondary measures of lesion load. Aerobic fitness increased in favour of the exercise group. Microstructural integrity was higher in four of eight a priori defined motor-related tracts and nuclei in the exercise group compared with the control (thalamus, corticospinal tract, globus pallidus, cingulate gyrus) at 48 weeks.

CONCLUSION

Early supervised aerobic exercise did not reduce relapse rate or global brain atrophy, but does positively affect the microstructural integrity of important motor-related tracts and nuclei.

Does physical exercise improve or deteriorate treatment of multiple sclerosis with mitoxantrone? Experimental autoimmune encephalomyelitis study in rats

Background

Mitoxantrone has proved efficacy in treatment of multiple sclerosis (MS). The fact that physical exercise could slow down the progression of disease and improve performance is still a debatable issue, hence; we aimed at studying whether combining mitoxantrone with exercise is of value in the management of MS.

Methods

Thirty-six male rats were divided into sedentary and exercised groups. During a 14-day habituation period rats were subjected to exercise training on a rotarod (30 min/day) before Experimental Autoimmune Encephalomyelitis (EAE) induction and thereafter for 17 consecutive days. On day 13 after induction, EAE groups (exercised &sedentary) were divided into untreated and mitoxantrone treated ones. Disease development was evaluated by motor performance and EAE score. Cerebrospinal fluid (CSF) was used for biochemical analysis. Brain stem and cerebellum were examined histopathological and immunohistochemically.

Results

Exercise training alone did not add a significant value to the studied parameters, except for reducing Foxp3 immunoreactivity in EAE group and caspase-3 in the mitoxantrone treated group. Unexpectedly, exercise worsened the mitoxantrone effect on EAE score, Bcl2 and Bax. Mitoxantrone alone decreased EAE/demyelination/inflammation scores, Foxp3 immunoreactivity, and interleukin-6, while increased the re-myelination marker BDNF without any change in tumor necrosis factor-α. It clearly interrupted the apoptotic pathway in brain stem, but worsened EAE mediated changes of the anti-apoptotic Bcl2 and pro-apoptotic marker Bax in the CSF.

Conclusions

The neuroprotective effect of mitoxantrone was related with remyelination, immunosuppressive and anti-inflammatory potentials. Exercise training did not show added value to mitoxantrone, in contrast, it disrupts the apoptotic pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00692-1.

Characterization of Radioiodinated Diaryl Oxadiazole Derivatives as SPECT Probes for Detection of Myelin in Multiple Sclerosis

Multiple sclerosis (MS) is an intractable disease of the central nervous system that results from destruction of the myelin sheath. Direct measurement of de- and remyelination is required for monitoring the disease stage of MS, but no useful method has been established. In this study, we characterized four diaryl oxadiazole derivatives as novel myelin-imaging probes for single photon emission computed tomography (SPECT). All the diaryl oxadiazole derivatives penetrated the blood-brain barrier in normal mice. Among them, the highest ratio of radioactivity accumulation in the white matter (myelin-rich region) against the gray matter (myelin-deficient region) was observed at 60 min postinjection of [¹²⁵I]1,3,4-PODP-DM in ex vivo autoradiography using normal mice. In the blocking study with ex vivo autoradiography, the radioactivity accumulation of [¹²⁵I]1,3,4-PODP-DM in the white matter markedly reduced. [¹²⁵I]1,3,4-PODP-DM detected demyelination in the ex vivo autoradiographic images of not only the spinal cord of the experimental autoimmune encephalomyelitis mice but also the brain after lysophosphatidylcholine (LPC) injection. In addition, [¹²³I]1,3,4-PODP-DM could image LPC-induced demyelination in the mouse brain with SPECT. These results suggest that [¹²³I]1,3,4-PODP-DM may be a potential SPECT probe for imaging myelin in MS.

Aerobic training improves blood-brain barrier and neuronal apoptosis in experimental autoimmune encephalomyelitis

OBJECTIVES

Blood-brain barrier (BBB) permeability is central in multiple sclerosis (MS) pathophysiology, and exercise may improve BBB integrity. The current study investigated the prophylactic and/ or therapeutic role of aerobic exercise (EX) training on BBB integrity in experimental autoimmune encephalomyelitis (EAE).

MATERIALS AND METHODS

Forty female Lewis rats were randomly divided into four groups. The experimental groups included: no-EAE induction+ no-exercise (no-EAE+ no-EX), no-EAE induction+ exercise (no-EAE+EX), EAE induction+ no-exercise (EAE+ no-EX), and EAE induction+ exercise (EAE+EX). The no-EAE+EX and EAE+EX groups performed six weeks of progressive aerobic exercise training. GFAP, angiopoietin 1 (Ang-1) expression, tight-junction (TJ) proteins of claudin-5 and occludin were measured as components of BBB integrity and the rate of neuronal apoptosis was evaluated in hippocampi.

RESULTS

A significant increase in GFAP and Ang-1 expression (P<0.001) and conversely a down-regulation in TJ proteins (P<0.05) was found in the brains of the no-EAE+EX group compared with the no-EAE+ no-EX group. The expression of GFAP and Ang-1 proteins significantly increased in the hippocampi of the EAE+ no-EX group (P<0.001), whereas aerobic training (in the EAE+EX group) meaningfully reversed such increases (P<0.001). Besides, down-regulated TJ proteins and increased neuronal apoptosis induced by EAE induction (EAE+ no-EX group) were restored and reduced, respectively, by aerobic training in the CNS of the EAE+EX group (P<0.001).

CONCLUSION

The provision of a six-week treadmill aerobic training buffered the detrimental effects of EAE on BBB integrity and consequently neuronal apoptosis.

Exercise Training for Multiple Sclerosis: A Narrative Review of History, Benefits, Safety, Guidelines, and Promotion

Background: There have been significant advances in the medical treatment and management of multiple sclerosis pathogenesis, relapse and disease progression over the past 30 years. There have been advancements in the symptomatic treatment of multiple sclerosis, including management of secondary multiple sclerosis expressions such as walking, cognitive dysfunction, fatigue and depression. Scientific evidence and expert opinion suggest that exercise may be the single most effective non-pharmacological symptomatic treatment for multiple sclerosis. This article presents the historical context of exercise training within the multidisciplinary management of multiple sclerosis. We guide neurologists and healthcare providers on the recommended prescription of exercise and practical, theoretical methods to overcome barriers to exercise. Method: We undertook a critical search of the historical and current literature regarding exercise and multiple sclerosis from the viewpoint of exercise promotion by neurologists and the multidisciplinary care team. Results: We highlight the ever-strengthening body of research indicating that exercise is safe and effective for improving symptoms of multiple sclerosis. Further, exercise training may be necessary for reducing disease progression. Conclusion: We seek to encourage neurologists and specialists in multidisciplinary healthcare teams to prescribe and promote exercise at diagnosis and across all stages of the disease trajectory using prescriptive guidelines as part of comprehensive MS care. Available tools include clinical education to dispel any historical myths related to exercise in multiple sclerosis, clinical exercise guidelines and behaviour change theory to overcome patients barriers to exercise.

Therapeutic Effects of Physical Exercise and the Mesenchymal Stem Cell Secretome by Modulating Neuroinflammatory Response in Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative, demyelinating, and chronic inflammatory disease characterized by central nervous system (CNS) lesions that lead to high levels of disability and severe physical and cognitive disturbances. Conventional therapies are not enough to control the neuroinflammatory process in MS and are not able to inhibit ongoing damage to the CNS. Thus, the secretome of mesenchymal stem cells (MSC-S) has been postulated as a potential therapy that could mitigate symptoms and disease progression. We considered that its combination with physical exercise (EX) could induce superior effects and increase the MSC-S effectiveness in this condition. Recent studies have revealed that both EX and MSC-S share similar mechanisms of action that mitigate auto-reactive T cell infiltration, regulate the local inflammatory response, modulate the proinflammatory profile of glial cells, and reduce neuronal damage. Clinical and experimental studies have reported that these treatments in an isolated way also improve myelination, regeneration, promote the release of neurotrophic factors, and increase the recruitment of endogenous stem cells. Together, these effects reduce disease progression and improve patient functionality. Despite these results, the combination of these methods has not yet been studied in MS. In this review, we focus on molecular elements and cellular responses induced by these treatments in a separate way, showing their beneficial effects in the control of symptoms and disease progression in MS, as well as indicating their contribution in clinical fields. In addition, we propose the combined use of EX and MSC-S as a strategy to boost their reparative and immunomodulatory effects in this condition, combining their benefits on synaptogenesis, neurogenesis, remyelination, and neuroinflammatory response. The findings here reported are based on the scientific evidence and our professional experience that will bring significant progress to regenerative medicine to deal with this condition.

Effects of Exercise Training on Neurotrophic Factors and Subsequent Neuroprotection in Persons with Multiple Sclerosis-A Systematic Review and Meta-Analysis

Background: Evidence indicates that exercise holds the potential to counteract neurodegeneration experienced by persons with multiple sclerosis (pwMS), which is in part believed to be mediated through increases in neurotrophic factors. There is a need to summarize the existing evidence on exercise-induced effects on neurotrophic factors alongside neuroprotection in pwMS. Aim: To (1) systematically review the evidence on acute (one session) and/or chronic (several sessions) exercise-induced changes in neurotrophic factors in pwMS and (2) investigate the potential translational link between exercise-induced changes in neurotrophic factors and neuroprotection. Methods: Five databases (Medline, Scopus, Web of Science, Embase, Sport Discus) were searched for randomized controlled trials (RCT) examining the effects of exercise (all modalities included) on neurotrophic factors as well as measures of neuroprotection if reported. The quality of the study designs and the exercise interventions were assessed by use of the validated tool TESTEX. Results: From N = 337 identified studies, N = 14 RCTs were included. While only N = 2 of the identified studies reported on the acute changes in neurotrophic factors, all N = 14 RCTs reported on the chronic effects, with N = 9 studies revealing between-group differences in favor of exercise. This was most prominent for brain-derived neurotrophic factor (BDNF), with between-group differences in favor of exercise being observed in N = 6 out of N = 12 studies. Meta-analyses were applicable for three out of 10 different identified neurotrophic factors and revealed that exercise can improve the chronic levels of BDNF (delta changes; N = 9, ES = 0.78 (0.27; 1.28), p = 0.003, heterogeneity between studies) and potentially also ciliary neurotrophic factor (CNTF) (N = 3, ES = 0.24 (−0.07; 0.54), p = 0.13, no heterogeneity between studies) but not nerve growth factor (NGF) (N = 4, ES = 0.28 (−0.55; 1.11), p = 0.51, heterogeneity between studies). Indicators of neuroprotection (e.g., with direct measures of brain structure assessed by MRI) were assessed in N = 3 of the identified studies only, with N = 2 partly supporting and thus indicating a potential translational link between increases in neurotrophic factors and neuroprotection. Conclusion: The present study reveals that exercise can elicit improvements in chronic levels of BDNF in pwMS, whereas the effects of exercise on chronic levels of other neurotrophic factors and on acute levels of neurotrophic factors in general, along with a potential translational link (i.e., with exercise-induced improvements in neurotropic factors being associated with or even mediating neuroprotection), are sparse and inconclusive. There is a need for more high-quality studies that assess neurotrophic factors (applying comparable methods of blood handling and analysis) concomitantly with neuroprotective outcome measures. Review Registration: PROSPERO (ID: CRD42020177353).

MedXercise: a promising strategy to promote remyelination

Multiple sclerosis is an inflammatory and demyelinating disease of the central nervous system. While remyelination facilitates functional recovery in animal models, it is limited in people with multiple sclerosis. Thus, multiple strategies have been put forth to promote remyelination, including exercise and medication. Exercise promotes the release of growth factors and induces protein-level changes, while remyelinating medications act through a variety of mechanisms to promote oligodendrocyte maturation within the lesion. In animal models, the combination of medication and exercise (Medication + eXercise = MedXercise) has an additive effect on remyelination and other pathological features of multiple sclerosis. In this review, we highlight the existing literature on the effects of exercise and medication on remyelination both independently and in combination.

Brief electrical nerve stimulation enhances intrinsic repair capacity of the focally demyelinated central nervous system

Our lab has shown that brief electrical nerve stimulation (ES) has a dramatic impact on remyelination of lysophosphatidyl choline (LPC)-induced focally demyelinated rat peripheral nerves, while also inducing an axon-protective phenotype and shifting macrophages from a predominantly pro-inflammatory toward a pro-repair phenotype. Whether this same potential exists in the central nervous system is not known. Thus, for proof of principle studies, the peripheral nerve demyelination and ES model was adapted to the central nervous system, whereby a unilateral focal LPC-induced demyelination of the dorsal column at the lumbar enlargement where the sciatic nerve afferents enter was created, so that subsequent ipsilateral sciatic nerve ES results in increased neural activity in the demyelinated axons. Data reveal a robust focal demyelination at 7 days post-LPC injection. Delivery of 1-hour ES at 7 days post-LPC polarizes macrophages/microglia toward a pro-repair phenotype when examined at 14 days post-LPC; results in smaller LPC-associated regions of inflammation compared to non-stimulated controls; results in significantly more cells of the oligodendroglial lineage in the demyelinated region; elevates myelin basic protein levels; and shifts the paranodal protein Caspr along demyelinated axons to a more restricted distribution, consistent with reformation of the paranodes of the nodes of Ranvier. ES also significantly enhanced levels of phosphorylated neurofilaments detected in the zones of demyelination, which has been shown to confer axon protection. Collectively these findings support that strategies that increase neural activity, such as brief electrical stimulation, can be beneficial for promoting intrinsic repair following focal demyelinating insults in demyelinating diseases such as multiple sclerosis. All animal procedures performed were approved by the University of Saskatchewan's Animal Research Ethics Board (protocol# 20090087; last approval date: November 5, 2020).

Exercise rapidly alters proteomes in mice following spinal cord demyelination

Exercise affords broad benefits for people with multiple sclerosis (PwMS) including less fatigue, depression, and improved cognition. In animal models of multiple sclerosis (MS), exercise has been shown to improve remyelination, decrease blood-brain barrier permeability and reduce leukocyte infiltration. Despite these benefits many PwMS refrain from engaging in physical activity. This barrier to participation in exercise may be overcome by uncovering and describing the mechanisms by which exercise promotes beneficial changes in the central nervous system (CNS). Here, we show that acute bouts of exercise in mice profoundly alters the proteome in demyelinating lesions. Following lysolecithin induced demyelination of the ventral spinal cord, mice were given immediate access to a running wheel for 4 days. Lesioned spinal cords and peripheral blood serum were then subjected to tandem mass tag labeling shotgun proteomics workflow to identify alteration in protein levels. We identified 86 significantly upregulated and 85 downregulated proteins in the lesioned spinal cord as well as 14 significantly upregulated and 11 downregulated proteins in the serum following acute exercise. Altered pathways following exercise in demyelinated mice include oxidative stress response, metabolism and transmission across chemical synapses. Similar acute bout of exercise in naïve mice also changed several proteins in the serum and spinal cord, including those for metabolism and anti-oxidant responses. Improving our understanding of the mechanisms and duration of activity required to influence the injured CNS should motivate PwMS and other conditions to embrace exercise as part of their therapy to manage CNS disability.

Exercise and the brain in multiple sclerosis

While people with multiple sclerosis (PwMS) historically were advised to avoid physical activity to reduce symptoms such as fatigue, they are now encouraged to remain active and to enlist in programs of exercise. However, despite an extensive current literature that exercise not only increases physical well-being but also their cognition and mental health, many PwMS are not meeting recommended levels of exercise. Here, we emphasize the impact and mechanisms of exercise on functional and structural changes to the brain, including improved connectome, neuroprotection, neurogenesis, oligodendrogenesis, and remyelination. We review evidence from animal models of multiple sclerosis (MS) that exercise protects and repairs the brain, and provide supportive data from clinical studies of PwMS. We introduce the concept of MedXercise, where exercise provides a brain milieu particularly conducive for a brain regenerative medication to act upon. The emphasis on exercise improving brain functions and repair should incentivize PwMS to remain physically active.

Training the brain: could it improve multiple sclerosis treatment?

Multiple sclerosis (MS) is a neurological disease characterized by neuroinflammation, demyelination and axonal degeneration along with loss of function in the central nervous system. For many years, research in MS has focused on the efficacy of pharmacological treatments. However, during the last years, many publications have been dedicated to the study of the efficacy of non-pharmacological strategies, such as physical exercise and cognitive training. Beneficial effects of the combination of both strategies on cognitive function have been described in both ageing adults and patients with neurodegenerative diseases, such as MS. The analysis of combining both physical and cognitive stimulation can be summarized by the environmental enrichment (EE) experiments, which are more suitable for animal models. EE refers to housing conditions consisting of exercise and cognitive and social stimulation. In this review, we will summarize the available studies that describe the influence of EE in both MS patients and MS animal models.

Alternative splicing of neurexins 1-3 is modulated by neuroinflammation in the prefrontal cortex of a murine model of multiple sclerosis

Mounting evidence points to immune-mediated synaptopathy and impaired plasticity as early pathogenic events underlying cognitive decline (CD) in Multiple sclerosis (MS) and in the experimental autoimmune encephalomyelitis (EAE) mouse model of the disease. However, knowledge of the neurobiology of synaptic dysfunction is still incomplete. Splicing regulation represents a flexible and powerful mechanism involved in dynamic remodeling of the synapse, which allows the expression of synaptic protein variants that dynamically control the specificity of contacts between neurons. The pre-synaptic adhesion molecules neurexins (NRXNs) 1-3 play a relevant role in cognition and are alternatively spliced to yield variants that differentially cluster specific ligands in the postsynaptic compartment and modulate functional properties of the synaptic contact. Notably, mutations in these genes or disruption of their splicing program are associated with neuropsychiatric disorders. Herein, we have investigated how inflammatory changes imposed by EAE impact on alternative splicing of the Nrxn 1-3 mouse genes in the acute phase of disease. Due to its relevance in cognition, we focused on the prefrontal cortex (PFC) of SJL/J mice, in which EAE-induced inflammatory lesions extend to the rostral forebrain. We found that inclusion of the Nrxn 1-3 AS4 exon is significantly increased in the PFC of EAE mice and that splicing changes are correlated with local Il1β-expression levels. This correlation is sustained by the concomitant downregulation of SLM2, the main splicing factor involved in skipping of the AS4 exon, in EAE mice displaying high levels of Il1β- expression. We also observed that Il1β-expression levels correlate with changes in parvalbumin (PV)-positive interneuron connectivity. Moreover, exposure to environmental enrichment (EE), a condition known to stimulate neuronal connectivity and to improve cognitive functions in mice and humans, modified PFC phenotypes of EAE mice with respect to Il1β-, Slm2-expression, Nrxn AS4 splicing and PV-expression, by limiting changes associated with high levels of inflammation. Our results reveal that local inflammation results in early splicing modulation of key synaptic proteins and in remodeling of GABAergic circuitry in the PFC of SJL/J mice. We also suggest EE as a tool to counteract these inflammation-associated events, thus highlighting potential therapeutic targets for limiting the progressive CD occurring in MS.

Inflammation-Associated Synaptic Alterations as Shared Threads in Depression and Multiple Sclerosis

In the past years, several theories have been advanced to explain the pathogenesis of Major Depressive Disorder (MDD), a neuropsychiatric disease that causes disability in general population. Several theories have been proposed to define the MDD pathophysiology such as the classic "monoamine-theory" or the "glutamate hypothesis." All these theories have been recently integrated by evidence highlighting inflammation as a pivotal player in developing depressive symptoms. Proinflammatory cytokines have been indeed claimed to contribute to stress-induced mood disturbances and to major depression, indicating a widespread role of classical mediators of inflammation in emotional control. Moreover, during systemic inflammatory diseases, peripherally released cytokines circulate in the blood, reach the brain and cause anxiety, anhedonia, social withdrawal, fatigue, and sleep disturbances. Accordingly, chronic inflammatory disorders, such as the inflammatory autoimmune disease multiple sclerosis (MS), have been associated to higher risk of MDD, in comparison with overall population. Importantly, in both MS patients and in its experimental mouse model, Experimental Autoimmune Encephalomyelitis (EAE), the notion that depressive symptoms are reactive epiphenomenon to the MS pathology has been recently challenged by the evidence of their early manifestation, even before the onset of the disease. Furthermore, in association to such mood disturbance, inflammatory-dependent synaptic dysfunctions in several areas of MS/EAE brain have been observed independently of brain lesions and demyelination. This evidence suggests that a fine interplay between the immune and nervous systems can have a huge impact on several neurological functions, including depressive symptoms, in different pathological conditions. The aim of the present review is to shed light on common traits between MDD and MS, by looking at inflammatory-dependent synaptic alterations associated with depression in both diseases.

Recent Advances in Antigen-Specific Immunotherapies for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system and is considered to be the leading non-traumatic cause of neurological disability in young adults. Current treatments for MS comprise long-term immunosuppressant drugs and disease-modifying therapies (DMTs) designed to alter its progress with the enhanced risk of severe side effects. The Holy Grail for the treatment of MS is to specifically suppress the disease while at the same time allow the immune system to be functionally active against infectious diseases and malignancy. This could be achieved via the development of immunotherapies designed to specifically suppress immune responses to self-antigens (e.g., myelin antigens). The present study attempts to highlight the various antigen-specific immunotherapies developed so far for the treatment of multiple sclerosis (e.g., vaccination with myelin-derived peptides/proteins, plasmid DNA encoding myelin epitopes, tolerogenic dendritic cells pulsed with encephalitogenic epitopes of myelin proteins, attenuated autologous T cells specific for myelin antigens, T cell receptor peptides, carriers loaded/conjugated with myelin immunodominant peptides, etc), focusing on the outcome of their recent preclinical and clinical evaluation, and to shed light on the mechanisms involved in the immunopathogenesis and treatment of multiple sclerosis.

Moving exercise research in multiple sclerosis forward (the MoXFo initiative): Developing consensus statements for research

Exercise as a subset of physical activity is a cornerstone in the management of multiple sclerosis (MS) based on its pleotropic effects. There is an exponential increase in the quantity of research on exercise in MS, yet a number of barriers associated with study content and quality hamper rapid progress in the field. To address these barriers and accelerate discovery, a new international partnership of MS-related experts in exercise has emerged with the goal of advancing the research agenda. As a first step, the expert panel met in May 2018 and identified the most urgent areas for moving the field forward, and discussed the framework for such a process. This led to identification of five themes, namely "Definitions and terminology," "Study methodology," "Reporting and outcomes," "Adherence to exercise," and "Mechanisms of action." Based on the identified themes, five expert groups have been formed, that will further (a) outline the challenges per theme and (b) provide recommendations for moving forward. We aim to involve and collaborate with people with MS/MS organizations (e.g. Multiple Sclerosis International Federation (MSIF) and European Multiple Sclerosis Platform (EMSP)) in all of these five themes. The generation of this thematic framework with multi-expert perspectives can bolster the quality and scope of exercise studies in MS that may ultimately improve the daily lives of people with MS.

Vigorous cool room treadmill training to improve walking ability in people with multiple sclerosis who use ambulatory assistive devices: a feasibility study

BACKGROUND

Aerobic training has the potential to restore function, stimulate brain repair, and reduce inflammation in people with Multiple Sclerosis (MS). However, disability, fatigue, and heat sensitivity are major barriers to exercise for people with MS. We aimed to determine the feasibility of conducting vigorous harness-supported treadmill training in a room cooled to 16 °C (10 weeks; 3times/week) and examine the longer-term effects on markers of function, brain repair, and inflammation among those using ambulatory aids.

METHODS

Ten participants (9 females) aged 29 to 74 years with an Expanded Disability Status Scale ranging from 6 to 7 underwent training (40 to 65% heart rate reserve) starting at 80% self-selected walking speed. Feasibility of conducting vigorous training was assessed using a checklist, which included attendance rates, number of missed appointments, reasons for not attending, adverse events, safety hazards during training, reasons for dropout, tolerance to training load, subjective reporting of symptom worsening during and after exercise, and physiological responses to exercise. Functional outcomes were assessed before, after, and 3 months after training. Walking ability was measured using Timed 25 Foot Walk test and on an instrumented walkway at both fast and self-selected speeds. Fatigue was measured using fatigue/energy/vitality sub-scale of 36-Item Short-Form (SF-36) Health Survey, Fatigue Severity Scale, modified Fatigue Impact Scale. Aerobic fitness (maximal oxygen consumption) was measured using maximal graded exercise test (GXT). Quality-of-life was measured using SF-36 Health Survey. Serum levels of neurotrophin (brain-derived neurotrophic factor) and cytokine (interleukin-6) were assessed before and after GXT.

RESULTS

Eight of the ten participants completed training (attendance rates ≥ 80%). No adverse events were observed. Fast walking speed (cm/s), gait quality (double-support (%)) while walking at self-selected speed, fatigue (modified Fatigue Impact Scale), fitness (maximal workload achieved during GXT), and quality-of-life (physical functioning sub-scale of SF-36) improved significantly after training, and improvements were sustained after 3-months. Improvements in fitness (maximal respiratory exchange ratio and maximal oxygen consumption during GXT) were associated with increased brain-derived neurotrophic factor and decreased interleukin-6.

CONCLUSION

Vigorous cool room training is feasible and can potentially improve walking, fatigue, fitness, and quality-of-life among people with moderate to severe MS-related disability.

TRIAL REGISTRATION

The study was approved by the Newfoundland and Labrador Health Research Ethics Board (reference number: 2018.088) on 11/07/2018 prior to the enrollment of first participant (retrospectively registered at ClinicalTrials.gov: NCT04066972. Registered on 26 August 2019.