Exercise and brain health--implications for multiple sclerosis: Part 1--neuronal growth factors

Pilot study: evaluation of the effect of functional electrical stimulation cycling on muscle metabolism in nonambulatory people with multiple sclerosis

OBJECTIVE

To investigate the changes in muscle oxygen consumption (mV˙O2) using near-infrared spectroscopy (NIRS) after 4 weeks of training with functional electrical stimulation (FES) cycling in nonambulatory people with multiple sclerosis (MS).

DESIGN

Four-week before-after trial to assess changes in mV˙O2 after an FES cycling intervention.

SETTING

Rehabilitation hospital.

PARTICIPANTS

People (N=8; 7 men, 1 women) from a volunteer/referred sample with moderate to severe MS (Expanded Disability Status Scale score>6.0).

INTERVENTION

Participants cycled 30 minutes per session, 3d/wk for 4 weeks or a total of 12 sessions.

MAIN OUTCOME MEASURES

mV˙O2 of the right vastus lateralis muscle was measured with NIRS before and within 1 week after the intervention. Six bouts of 15-second electrical stimulation increasing from 2 to 7Hz were used to activate the muscle. mV˙O2 was assessed by analyzing the slope of the NIRS oxygen signal during a 10-second arterial occlusion after each electrical stimulation bout.

RESULTS

Significant FES training by electrical stimulation frequency level interaction was observed (P=.031), with an average increase in mV˙O2 of 47% across frequencies with a main effect of training (P=.047).

CONCLUSIONS

FES cycling for 4 weeks improved mV˙O2, suggesting that FES cycling is a potential therapy for improving muscle health in people with MS who are nonambulatory.

Exercise testing and training in people with Huntington's disease

OBJECTIVE

To explore exercise response in people with Huntington's disease (HD).

DESIGN

Experimental observational study with a randomly allocated subgroup before/after interventional study.

SETTING

Community.

SUBJECTS

People with HD (n=30) and a healthy comparator group (n=20). Thirteen people from the HD group were randomly allocated to an exercise training program.

MAIN MEASURES

Heart rate (HR) and perceived exertion on the Borg-CR10 scale (RPE) during a submaximal cycle ergometer exercise test (three minute unloaded and nine minute 65%-75%HRmaximum phase). Expired air and lactate measures were available for 8 people with HD during the exercise.

INTERVENTION

A 12 week gym and home walking exercise programme (n=13).

RESULTS

People with HD achieved a lower work rate at nine minutes (82±42(0-195) v 107±35(50 -185) Watts (p<0.05)), but higher RPE at both three (3±2(0-7) v 1±1(0-4)) and nine minutes (7±3(1-10) v 5± 2(2-9)) both p<0.01, compared to the healthy group and did not achieve a steady state HR during unloaded cycling. People with HD also demonstrated higher than expected lactate at three 2.5±2.5(1.1-8)mmo.L-1 and nine 3.8±1.9(1.2-6.6)mmo.L-1 minutes and respiratory exchange ratio at three 0.78±0.03 (0.74-0.81) and nine minutes 0.94±0.11(0.81-1.15). After exercise training there were no changes observed in HR or RPE responses during the exercise test.

CONCLUSIONS

There was a large variability in the observed metabolic and physiological responses to exercise in people with HD. The observed exercise responses suggest that altered exercise prescription parameters may be required for people with HD and that exercise response and factors' affecting this requires further investigation.

Association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome

Limited scientific evidence suggests that physical activity is directly related to cognitive performance in patients with chronic fatigue syndrome (CFS). To date, no other study has examined the direct relationship between cognitive performance and physical fitness in these patients. This study examined whether cognitive performance and physical fitness are associated in female patients with CFS and investigated the association between cognitive performance and physical activity level (PAL) in the same study sample. We hypothesized that patients who performed better on cognitive tasks would show increased PALs and better performance on physical tests. The study included 31 women with CFS and 13 healthy inactive women. Participants first completed three cognitive tests. Afterward, they undertook a test to determine their maximal handgrip strength, performed a bicycle ergometer test, and were provided with an activity monitor. In patients with CFS, lower peak oxygen uptake and peak heart rate were associated with slower psychomotor speed (p < 0.05). Maximal handgrip strength was correlated with working memory performance (p < 0.05). Both choice and simple reaction time were lower in patients with CFS relative to healthy controls (p < 0.05 and p < 0.001, respectively). In conclusion, physical fitness, but not PAL, is associated with cognitive performance in female patients with CFS.

The role of exercise in modifying outcomes for people with multiple sclerosis: a randomized trial

BACKGROUND

Despite the commonly known benefits of exercise and physical activity evidence shows that persons Multiple Sclerosis (MS) are relatively inactive yet physical activity may be even more important in a population facing functional deterioration. No exercise is effective if it is not done and people with MS face unique barriers to exercise engagement which need to be overcome. We have developed and pilot tested a Multiple Sclerosis Tailored Exercise Program (MSTEP) and it is ready to be tested against general guidelines for superiority and ultimately for its impact on MS relevant outcomes. The primary research question is to what extent does an MS Tailored Exercise Program (MSTEP) result in greater improvements in exercise capacity and related outcomes over a one year period in comparison to a program based on general guidelines for exercise among people with MS who are sedentary and wish to engage in exercise as part of MS self-management.

METHODS/DESIGN

The proposed study is an assessor-blind, parallel-group, randomized controlled trial (RCT). The duration of the intervention will be one year with follow-up to year two. The targeted outcomes are exercise capacity, functional ambulation, strength, and components of quality of life including frequency and intensity of fatigue symptoms, mood, global physical function, health perception, and objective measures of activity level. Logistic regression will be used to test the main hypothesis related to the superiority of the MSTEP program based on a greater proportion of people making a clinically relevant gain in exercise capacity at 1 year and at 2 years, using an intention-to-treat approach. Sample size will be 240 (120 per group).

DISCUSSION

The MS community is clearly looking for interventions to help alleviate the disabling sequelae of MS and promote health. Exercise is a well-known intervention which has known benefits to all, yet few exercise regularly. For people with MS, the role of exercise in MS management needs to be rigorously assessed to inform people as to how best to use exercise to reduce disability and promote health.

TRIAL REGISTRATION

Clinical Trials.gov: NCT01611987.

Physical fitness, walking performance, and gait in multiple sclerosis

BACKGROUND

Walking impairment is a prevalent, life-altering feature of multiple sclerosis (MS). There has been recent speculation that physiological deconditioning (i.e., reductions in aerobic capacity, balance, and muscular strength) contributes to walking and gait impairments in MS.

OBJECTIVE

This study examined the associations among aerobic capacity, balance, and lower-limb strength asymmetries, walking performance, and gait kinematics in 31 persons with MS and 31 matched controls.

METHODS

Participants underwent standard assessments of peak aerobic capacity, muscular strength (i.e., asymmetry between knee muscles), and balance. Walking performance was measured using the timed 25-ft walk (T25FW) and six-minute walk (6MW). Gait parameters were captured using a GaitRite™ electronic walkway.

RESULTS

Aerobic capacity, balance, and knee-extensor asymmetry were associated with walking performance and gait in persons with MS (r=.2-.6) and explained differences in walking and gait variables between MS and control groups (∆R(2)=.27-.34). Aerobic capacity and lower-limb strength asymmetries, but not balance, explained significant variance in walking performance and gait kinematics in the MS sample (R(2)=.32-.58).

CONCLUSIONS

Physiological deconditioning explains variability in walking disability in persons with MS and might represent a target of multimodal exercise training interventions for improving mobility outcomes in this population.

Steps per day among persons with multiple sclerosis: variation by demographic, clinical, and device characteristics

OBJECTIVES

To identify steps per day in a large sample of persons with multiple sclerosis (MS) and to describe variation by demographic and clinical characteristics and device type.

DESIGN

Cross-sectional design.

SETTING

General community.

PARTICIPANTS

Convenience sample of persons with multiple sclerosis (N=645) recruited from the general community who were ambulatory and relapse free for 30 days. Mean age ± SD of the participants was 46.3 ± 10.6 years old. Participants were mostly women (85%), white (93%), and employed (64%).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Step counts measured by a motion sensor during a 7-day period.

RESULTS

The average value for the entire sample was 5,903 ± 3,185 steps per day. This value varied by demographic and clinical characteristics, but not device type, and indicated that men, participants who were unemployed, had a high school education or less, progressive MS, a longer disease duration, and higher disability were less physically active based on the metric of steps per day.

CONCLUSIONS

This study provides an expected value for average steps per day among persons with MS. Such an expected value for this population is an important first step to help researchers and clinicians interested in improving the overall health of persons with MS through physical activity promotion.

Neuroprotection for amyotrophic lateral sclerosis: role of stem cells, growth factors, and gene therapy

Various molecular mechanisms including apoptosis, inflammation, oxidative stress, mitochondrial dysfunction and excitotoxicity have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), though the exact mechanisms have yet to be specified. Furthermore, the underlying restorative molecular mechanisms resulting in neuronal and/or non-neuronal regeneration have to be yet elucidated. Therapeutic agents targeting one or more of these mechanisms to combat either initiation or progression of the disease are under research. Novel treatments including stem cell therapy, growth factors, and gene therapy might prolong survival and delay progression of symptoms. Harnessing the regenerative potential of the central nervous system would be a novel approach for the treatment of motor neuron death resulting from ALS. Endogenous neural replacement, if augmented with administration of exogenous growth factors or with pharmaceuticals that increase the rate of neural progenitor formation, neural migration, and neural maturation could slow the rate of cell loss enough to result in clinical improvement. In this review, we discuss the impact of therapeutic treatment involving stem cell therapy, growth factors, gene therapy, and combination therapy on disease onset and progression of ALS. In addition, we summarize human clinical trials of stem cell therapy, growth factor therapy, and gene therapy in individuals with ALS.

The benefits of exercise training in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease characterized by inflammatory demyelination and neurodegeneration within the CNS. This damage of CNS structures leads to deficits of body functions, which, in turn, affect patient activities, such as walking, and participation. The pathogenesis and resulting consequences of MS have been described as concepts within the International Classification of Functioning, Disability and Health (ICF) model--an international standard to describe and measure health and disability. Evidence suggests that exercise training in people with MS has the potential to target and improve many of the components outlined in the ICF model. Although the body of research examining the effects of exercise training on depression, cognition and participatory outcomes is not sufficiently developed, some preliminary evidence is promising. Exercise training is proposed to affect inflammation, neurodegeneration, and CNS structures, but current evidence is limited. In this Review, we discuss evidence from clinical trials that suggests beneficial effects of exercise training on muscle strength, aerobic capacity and walking performance, and on fatigue, gait, balance and quality of life. Issues with current studies and areas of future research are highlighted.

Exercise and disease progression in multiple sclerosis: can exercise slow down the progression of multiple sclerosis?

It has been suggested that exercise (or physical activity) might have the potential to have an impact on multiple sclerosis (MS) pathology and thereby slow down the disease process in MS patients. The objective of this literature review was to identify the literature linking physical exercise (or activity) and MS disease progression. A systematic literature search was conducted in the following databases: PubMed, SweMed+, Embase, Cochrane Library, PEDro, SPORTDiscus and ISI Web of Science. Different methodological approaches to the problem have been applied including (1) longitudinal exercise studies evaluating the effects on clinical outcome measures, (2) cross-sectional studies evaluating the relationship between fitness status and MRI findings, (3) cross-sectional and longitudinal studies evaluating the relationship between exercise/physical activity and disability/relapse rate and, finally, (4) longitudinal exercise studies applying the experimental autoimmune encephalomyelitis (EAE) animal model of MS. Data from intervention studies evaluating disease progression by clinical measures (1) do not support a disease-modifying effect of exercise; however, MRI data (2), patient-reported data (3) and data from the EAE model (4) indicate a possible disease-modifying effect of exercise, but the strength of the evidence limits definite conclusions. It was concluded that some evidence supports the possibility of a disease-modifying potential of exercise (or physical activity) in MS patients, but future studies using better methodologies are needed to confirm this.

Exercise in multiple sclerosis -- an integral component of disease management

Multiple sclerosis (MS) is the most common chronic inflammatory disorder of the central nervous system (CNS) in young adults. The disease causes a wide range of symptoms depending on the localization and characteristics of the CNS pathology. In addition to drug-based immunomodulatory treatment, both drug-based and non-drug approaches are established as complementary strategies to alleviate existing symptoms and to prevent secondary diseases. In particular, physical therapy like exercise and physiotherapy can be customized to the individual patient's needs and has the potential to improve the individual outcome. However, high quality systematic data on physical therapy in MS are rare. This article summarizes the current knowledge on the influence of physical activity and exercise on disease-related symptoms and physical restrictions in MS patients. Other treatment strategies such as drug treatments or cognitive training were deliberately excluded for the purposes of this article.

Regular exercise prevents oxidative stress in the brain of hyperphenylalaninemic rats

Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine and its metabolites. Clinical features of PKU patients include mental retardation, microcephaly, and seizures. Oxidative stress has been found in these patients, and is possibly related to neurophysiopatology of PKU. Regular exercise can leads to adaptation of antioxidant system, improving its capacity to detoxification reactive species. The aim of this study was to verify the effects of regular exercise on oxidative stress parameters in the brain of hyperphenylalaninemic rats. Animals were divided into sedentary (Sed) and exercise (Exe) groups, and subdivided into saline (SAL) and hyperphenylalaninemia (HPA). HPA groups were induced HPA through administration of alpha-methylphenylalanine and phenylalanine for 17 days, while SAL groups (n = 16-20) received saline. Exe groups conducted 2-week aerobic exercise for 20 min/day. At 18th day, animals were killed and the brain was homogenized to determine thiobarbituric acid reactives substances (TBA-RS) content, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Soleus muscles were collected to determine glycogen content as a marker of oxidative adaptation. Exe groups showed enhanced glycogen content. HPA condition caused an increase in TBA-RS and SOD, and reduces CAT and GPx. Exercise was able to prevent all changes seen in the HPA group, reaching control values, except for SOD activity. No changes were found in the ExeSAL group compared to SedSAL. Hyperphenylalaninemic rats were more responsive to the benefits provided by regular exercise. Physical training may be an interesting strategy to restore the antioxidant system in HPA.

Physical activity and the achievement gap among urban minority youth

OBJECTIVES

To outline the prevalence and disparities of physical activity among school-aged urban minority youth, causal pathways through which low levels of physical activity and fitness adversely affects academic achievement, and proven or promising approaches for schools to increase physical activity and physical fitness among youth.

METHODS

Literature review.

RESULTS

A large proportion of youth is insufficiently physically active. Estimates of population-wide levels of physical activity indicate that Black and Hispanic youth are less physically active than White youth, with disparities particularly evident for females. The population segments of youth with lowest levels of physical activity and fitness also have least access to school-based physical activity opportunities and resources. Physical activity affects metabolism and all major body systems, exerting powerful positive influences on the brain and spinal cord and, consequently, on emotional stability, physical health, and motivation and ability to learn. The cornerstone of school-based physical activity programs should be a high-quality physical education program based on national standards. Such programs are strongly recommended by the Task Force on Community Preventive Services as a way to increase physical activity and physical fitness among youth.

CONCLUSIONS

Physical inactivity is highly and disproportionately prevalent among school-aged urban minority youth, has a negative impact on academic achievement through its effects on cognition, and effective practices are available for schools to address this problem. Increasing students' physical activity and physical fitness can best be achieved through a comprehensive approach that includes physical education, wise use of recess and after-school times, co-curricular physical activity opportunities, and bicycling or walking to and from school.

The effectiveness of an exercise programme for elders with dementia in a Taiwanese day-care centre

The purpose was to examine the effectiveness of an exercise programme for elders with dementia in Taiwan aimed to maintain their activities of daily living such as feeding, dressing, grooming, washing and toileting. This was a single study group, repeated measure research design. Twenty-six dementia elders were recruited from a day-care centre located in southern Taiwan. Caregivers of the day-care centre provided all subjects an exercise programme. The exercise programme consisted of stretching and walking five times per week, and leg-weight bearing at least three times per week for 20-30 min each. The data were obtained three times (baseline, 2 months post intervention and 4 months post intervention). Results showed slight changes in the scores of one-leg-standing, 30 s chair rise, functional reach and get up and go test but were not statistically significant. Results also indicated that scores in the performance of activities of daily living were significantly higher than at baseline and at 4 months post intervention. In conclusion, this study provides information for dementia day-care centres in Taiwan about how elders with dementia can maintain physical fitness and perform activities of daily living.

Walking impairment in patients with multiple sclerosis: exercise training as a treatment option

Multiple sclerosis (MS) is a chronic disease of the central nervous system that culminates in the progression of physical and cognitive disability over time. Walking impairment is a ubiquitous feature of MS and a sentinel characteristic of the later or advanced stages of the disease. This paper presents a conceptual rationale along with empirical evidence for exercise training as a rehabilitation approach for managing walking impairment and improving walking function in persons with MS. Conceptually, MS is associated with a decrease in physical activity, which, in turn, can result in deconditioning across multiple domains of physiological functioning. The resulting deconditioning feeds back and further drives physical inactivity until a threshold is reached that likely initiates the progression of walking impairment in MS. Empirically, physical activity and exercise training have been associated with beneficial effects on walking function in persons with MS. This is based on cross-sectional, longitudinal, and experimental research that included diversity in the breadth of measures of walking, persons with MS, and exercise/physical activity characteristics. Of particular importance, future researchers might consider examining the combinatory effects of exercise training plus pharmacological agents on walking mobility in MS. Collectively, exercise training and physical activity might hold significant potential for the management of progressive mobility disability in MS.

Running exercise-induced up-regulation of hippocampal brain-derived neurotrophic factor is CREB-dependent

The past decade has witnessed burgeoning evidence that antidepressant medications and physical exercise increase the expression of hippocampal brain-derived neurotrophic factor (BDNF). This phenomenon has gained widespread appeal, because BDNF is one of the first macromolecules observed to play a central role not only in the treatment of mood disorders, but also in neuronal survival-, growth-, and plasticity-related signaling cascades. Thus, it has become critical to understand how BDNF synthesis is regulated. Much evidence exists that changes in BDNF expression result from the activation/phosphorylation of the transcription factor, cAMP-response-element binding protein (CREB) following the administration of antidepressant medications. Utilizing a mouse model genetically engineered with an inducible CREB repressor, our current study provides evidence that increases in BDNF expression and cellular survival signaling resulting from physical exercise are also dependent upon activation of this central transcription factor. The transcription and expression of hippocampal BDNF, as well as the activation of Akt, a key survival signaling molecule, were measured following acute exercise, and also following short-term treatment with the norepinephrine reuptake inhibitor, reboxetine. We found that both interventions led to a marked increase in hippocampal BDNF mRNA, BDNF protein, and Akt phosphorylation (as well as CREB phosphorylation) in wild-type mice. As expected, activation of the CREB repressor in mutant mice sharply decreased CREB phosphorylation. In addition, all measures noted above remained at baseline levels when mutant mice exercised or received reboxetine. Increases in BDNF and phospho-Akt were also prevented when mutant mice received a combination of exercise and antidepressant treatment. The results are discussed in the context of what is currently known about BDNF signaling.

Aerobic fitness is associated with gray matter volume and white matter integrity in multiple sclerosis

Alterations in gray and white matter have been well documented in individuals with multiple sclerosis. Severity and extent of such brain tissue damage have been associated with cognitive impairment, disease duration and neurological disability, making quantitative indices of tissue damage important markers of disease progression. In this study, we investigated the association between cardiorespiratory fitness and measures of gray matter atrophy and white matter integrity. Employing voxel-based approaches to analysis of gray matter and white matter, we specifically examined whether higher levels of fitness in multiple sclerosis participants were associated with preserved gray matter volume and integrity of white matter. We found a positive association between cardiorespiratory fitness and regional gray matter volumes and higher focal fractional anisotropy values. Statistical mapping revealed that higher levels of fitness were associated with greater gray matter volume in the midline cortical structures including the medial frontal gyrus, anterior cingulate cortex and the precuneus. Further, we also found that increasing levels of fitness were associated with higher fractional anisotropy in the left thalamic radiation and right anterior corona radiata. Both preserved gray matter volume and white matter tract integrity were associated with better performance on measures of processing speed. Taken together, these results suggest that fitness exerts a prophylactic influence on the structural decline observed early on, preserving neuronal integrity in multiple sclerosis, thereby reducing long-term disability.

Exercise and brain health--implications for multiple sclerosis: Part II--immune factors and stress hormones

Part I of this review addressed the possible modulatory role of exercise on neuronal growth factors to promote brain health in neurodegenerative diseases such as multiple sclerosis (MS), which is characterized by varied patterns of inflammation, demyelination and axonal loss. Part II presents evidence that supports the potential neuroprotective effect of exercise on the modulation of immune factors and stress hormones in MS. Many current therapies used to attenuate MS progression are mediated, at least in part, through alterations in the relative concentrations of pro- and anti-inflammatory cytokines. Exercise-induced alterations in local and systemic cytokine production may also benefit immune function in health and disease. Exercise immunomodulation appears to be mediated by a complex interaction of hormones, cytokines and neural factors that may favorably influence immune variables in MS. The promising interplay between exercise and brain health in MS deserves further investigation.