Neurotrophic factors in Parkinson's disease are regulated by exercise: Evidence-based practice

Changes of brain-derived neurotrophic factor (BDNF) levels after different exercise protocols: a systematic review of clinical studies in Parkinson's disease

Background: Brain-Derived Neurotrophic Factor (BDNF) serum levels are reduced in patients with Parkinson's Disease (PD). Objectives: This study aimed to assess the effect of exercise intensity, volume and type on BDNF levels in patients with PD. Methods: We searched clinicaltrials.gov, CINAHL, Embase, PubMed, Scopus, Web of Science for both controlled and non-controlled studies in patients with PD, published between 2003 and 2022, which assessed Brain-Derived Neurotrophic Factor before and after different exercise protocols. Exercise intensity was estimated using a time-weighted average of Metabolic Equivalent of Task (MET), while exercise volume was estimated by multiplying MET for the duration of exercise. Exercise types were classified as aerobic, resistance, balance and others. We computed two distinct standardized measures of effects: Hedges' g to estimate differences between experimental and control group in pre-post intervention BDNF changes, and Cohen's d to measure pre-post intervention changes in BDNF values for each study arm. Meta-regression and linear regression were used to assess whether these effect measures were associated with intensity, volume and type. PROSPERO registration number: CRD42023418629. Results: Sixteen studies (8 two-arm trials and 8 single-arm trials) including 370 patients with PD were eligible for the systematic review. Selected studies had a large variability in terms of population and intervention characteristics. The meta-analysis showed a significant improvement in BDNF levels in the exercise group compared to the control group, Hedges' g = 0.70 (95% CI: 0.03, 1.38), with substantial heterogeneity (I2 = 76.0%). Between-group differences in intensity were positively associated with change in BDNF in a subset of 5 controlled studies. In the analysis which included non-controlled studies, intensity and total exercise volume were both positively associated with BDNF change. No difference was found according to exercise type. Conclusion: Exercises of greater intensity may increase BDNF levels in patients with PD, while the role of volume of exercise needs to be further explored.

Risk factors associated with age at onset of Parkinson's disease in the UK Biobank

Substantial evidence shown that the age at onset (AAO) of Parkinson's disease (PD) is a major determinant of clinical heterogeneity. However, the mechanisms underlying heterogeneity in the AAO remain unclear. To investigate the risk factors with the AAO of PD, a total of 3156 patients with PD from the UK Biobank were included in this study. We evaluated the effects of polygenic risk scores (PRS), nongenetic risk factors, and their interaction on the AAO using Mann-Whitney U tests and regression analyses. We further identified the genes interacting with nongenetic risk factors for the AAO using genome-wide environment interaction studies. We newly found physical activity (P < 0.0001) was positively associated with AAO and excessive daytime sleepiness (P < 0.0001) was negatively associated with AAO, and reproduced the positive associations of smoking and non-steroidal anti-inflammatory drug intake and the negative association of family history with AAO. In the dose-dependent analyses, smoking duration (P = 1.95 × 10-6), coffee consumption (P = 0.0150), and tea consumption (P = 0.0008) were positively associated with AAO. Individuals with higher PRS had younger AAO (P = 3.91 × 10-5). In addition, we observed a significant interaction between the PRS and smoking for AAO (P = 0.0316). Specifically, several genes, including ANGPT1 (P = 7.17 × 10-7) and PLEKHA6 (P = 4.87 × 10-6), may influence the positive relationship between smoking and AAO. Our data suggests that genetic and nongenetic risk factors are associated with the AAO of PD and that there is an interaction between the two.

Self-directed physical activity interventions for motor symptoms and quality of life in early and mid-stage Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Self-directed physical activity (SDPA) has been found in previous research to alleviate some of the symptoms of early and mid-stage Parkinson's disease (PD) patients. So, this study aimed to determine the impact of SDPA on these patients in the areas of motor symptoms, and quality of life (QoL).

METHOD

PubMed, Embase, the Cochrane Library, the Web of Science, Scopus, and ProQuest were all searched. The risk-of-bias tool of Cochrane for randomized trials, Version 2 (RoB 2), was also used to assess the credibility of studies in terms of their procedures.

RESULTS

15 eligible studies were analyzed. SDPA improved motor function and mobility, including timed up and go (TUG) test [standardized mean difference (SMD), -0.55 (95% CI, -0.91 - -0.18), p = 0.003], 6-minute walking (6MW) test [1.11 (0.75 - 1.47), p < 0.00001], stride length [0.45 (0.18 - 0.72), p = 0.001], gait velocity [0.42 (0.04 - 0.81 p = 0.03], Unified Parkinson's Disease Rating Scale Part-III (UPDRS-III) [-0.76 (-1.18 - -0.33), p = 0.0005] and enhanced Berg Balance Scale (BBS) [0.88 (0.50 - 1.27), p < 0.00001]). Despite engaging in SDPA, there was no significant improvement observed in freezing of gait (FOG) [0.23 (-0.11 - 0.56), p = 0.18] as well as the Parkinson's Disease Questionnaire-39 (PDQ-39) [0.04 (-0.55 - 0.62), p = 0.90]).

CONCLUSION

The motor symptoms of those with early to mid-stage PD improved with SDPA, however the research found no enhancement in FOG or QoL.

Physical Exercise Promotes Beneficial Changes on Neurotrophic Factors in Mesolimbic Brain Areas After AMPH Relapse: Involvement of the Endogenous Opioid System

Addiction is a serious public health problem, and the current pharmacotherapy is unable to prevent drug use reinstatement. Studies have focused on physical exercise as a promising coadjuvant treatment. Our research group recently showed beneficial neuroadaptations in the dopaminergic system related to amphetamine-relapse prevention involving physical exercise-induced endogenous opioid system activation (EXE-OS activation). In this context, additional mechanisms were explored to understand the exercise benefits on drug addiction. Male rats previously exposed to amphetamine (AMPH, 4.0 mg/kg) for 8 days were submitted to physical exercise for 5 weeks. EXE-OS activation was blocked by naloxone administration (0.3 mg/kg) 5 min before each physical exercise session. After the exercise protocol, the rats were re-exposed to AMPH for 3 days, and in sequence, euthanasia was performed and the VTA and NAc were dissected. In the VTA, our findings showed increased immunocontent of proBDNF, BDNF, and GDNF and decreased levels of AMPH-induced TrkB; therefore, EXE-OS activation increased all these markers and naloxone administration prevented this exercise-induced effect. In the NAc, the same molecular markers were also increased by AMPH and decreased by EXE-OS activation. In this study, we propose a close relation between EXE-OS activation beneficial influence and a consequent neuroadaptation on neurotrophins and dopaminergic system levels in the mesolimbic brain area, preventing the observed AMPH-relapse behavior. Our outcomes bring additional knowledge concerning addiction neurobiology understanding and show that EXE-OS activation may be a potential adjuvant tool in drug addiction therapy.

Physical activity and neurotrophic factors as potential drivers of neuroplasticity in Parkinson's Disease: A systematic review and meta-analysis

Parkinson's disease (PD) is a neurodegenerative disorder, characterized by motor and non-motor symptoms, that still lacks of a disease-modifying treatment. Consistent evidence proved the benefits of physical therapy on motor and non-motor symptoms in PD patients, leading the scientific community to propose physical activity as disease-modifying therapy for PD and suggesting the involvement of neurotrophic factors (NFs) as key mediators of neuroplasticity. However, the lack of standardized exercise training and methodological flaws of clinical trials have limited the evidence demonstrating the exercise-induced changes in serum and plasma neurotrophic factors concentration. A systematic search, covering 20 years of research in this field and including randomized and non-randomized controlled trials (RCTs and non-RCTs), which reported changes in serum and plasma NFs after a specific intervention, were reviewed. Pooled effect sizes (p-ESs) and 95% confidence intervals (95%CIs) were calculated using a random effects model with R software. A total of 18 articles, of which exercise programs of interventions were codified in terms of type, intensity and duration adopting a standardisation methodology, were included in the systematic review. Six papers, describing the effect of different training programs on BDNF and IGF-1 levels, were included and independently analysed in two meta-analyses. Quantitative analysis for BDNF indicated a statistically significant improvement in serum concentration of PD patients (MD: 5.99 ng/mL; 95%IC: 0.15 -11.83; I2 = 77%) performing physical activity compared with control conditions in RCTs. Preliminary evidence supported the hypothesis that a moderate intensity aerobic exercise (MIAE) would be necessary to induce the changes in NFs. However, sensitivity analysis of meta-analysis and the few studies included in subgroup analysis did not support these results. Alongside, meta-analysis followed by sensitivity analysis revealed a potential change in serum IGF-1 (MD: 33.47 ng/mL; 95%IC: 8.09-58.85) in PD patients performing physical activity with respect controls in RCT studies. Considering the limited evidence to support or refute the increase in NFs levels in PD patients performing physical activity, there is a need to develop a rigorous controlled randomized trial, with standardization for loading intensity of physical activity, greater sample size, and a correct stratification of PD patients to establish a well-defined correlation between physical activity and NFs levels.

Personalized Integrated Care Promoting Quality of Life for Older People: Protocol for a Multicenter Randomized Controlled Trial

BACKGROUND

Alzheimer disease (AD) and Parkinson disease (PD) are the 2 most common neurodegenerative diseases affecting millions of people worldwide. The Personalized Integrated Care Promoting Quality of Life for Older People (PC4L) project proposes an integrated, scalable, and interactive care ecosystem that can be easily adapted to the needs of several neurodegenerative and chronic diseases, care institutions, and end user requirements.

OBJECTIVE

The study protocol developed within the framework of the PC4L project aims to iteratively test the integrated platform and its modules, and focuses primarily on assessing the impact of the proposed solution (ie, the PC4L platform) on patients' quality of life, as well as its usability and feasibility on a large-scale sample size in 3 different scenarios (home, neurorehabilitation, and day care centers).

METHODS

A prospective multicenter clinical study is conducted in 5 European countries (Germany, Italy, Portugal, Romania, and Spain) at 6 different pilot centers, for 3 months, in patients with PD, Parkinsonism, AD, and other dementias (ODs). Patients were randomized in a ratio of 1:1 to the intervention group (use of the PC4L system) or the control group (no intervention). The PC4L system consists mainly of a wristband for monitoring parameters such as steps and levels of physical activity, and the PC4L app, which includes different engaging functionalities. Both groups are assessed through baseline and end-of-study clinical evaluations, including assessment of quality of life through the EQ-5D-3L scale.

RESULTS

The study protocol is part of a project approved and funded by the European Commission Horizon 2020 (grant agreement number 875221). The ethics committees of all involved centers reviewed and approved the study protocol. The study began with the recruitment phase in September 2022, and enrollment ended in February 2023. Recruitment is now closed (April 2023). The results of this study are expected to be published in summer 2023. A total of 558 patients, 279 per study group, were recruited. The results will allow to clarify the impact of PC4L on quality of life, will assess the empowerment of patients and the medical resources use, as well as the usability of the final version of the PC4L system. It will also provide information on the support of the system as a tool to facilitate the decision-making process.

CONCLUSIONS

The PC4L project intends to test a technology-based, integrated, scalable, and interactive care platform on patients with neurodegenerative diseases and proposes a good coordinated care model between all involved actors. Future developments of the PC4L solution may involve caregivers and socio-health professionals in the decision-making process in order to facilitate efficient communication between all stakeholders and ensure reliable and protected access to data within Europe.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05538455; https://clinicaltrials.gov/study/NCT05538455.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/47916.

Walking exercise alters pedunculopontine nucleus connectivity in Parkinson’s disease in a dose-dependent manner

Background

Gait disturbances are critical motor symptoms in Parkinson’s disease (PD). The mechanisms of gait impairment in PD are not entirely understood but likely involve changes in the Pedunculopontine Nucleus (PPN), a critical locomotion center, and its associated connections. Exercise is universally accepted as helpful in PD, but the extent and intensity of exercise required for plastic changes are unclear.

Methods

Twenty-seven PD subjects participated in a 3-month gait training intervention. Clinical assessments and resting-state functional magnetic resonance imaging were performed at baseline and 3 months after exercise. Functional connectivity of PPN was assessed by combining the methods of partial least squares, conditional dependence and partial correlation. In addition, paired t-tests were used to examine the effect of exercise on PPN functional connectivity and clinical measures, and Pearson’s correlation was used to assess the association between altered PPN functional connectivity and clinical measures.

Results

Exercise significantly improved Unified Parkinson’s Disease Rating Scale-III (UPDRS-III). A significant increase in right PPN functional connectivity was observed after exercise, which did not correlate with motor improvement. However, the decrease in left PPN functional connectivity significantly correlated with the improvement in UPDRS-III and was linearly related to both number of walks and the duration of walks. In addition, exercise induced a significant increase in the laterality of PPN connectivity strength, which correlated with motor improvement.

Conclusion

PPN functional connectivity is modifiable by walking exercise in both a dose-independent (right PPN and laterality of PPN connectivity strength) and dose-dependent (left PPN) manner. The PPN may contribute to pathological and compensatory processes in PD gait control. The observed gait improvement by walking exercise is most likely due to the reversal of the maladaptive compensatory mechanism. Altered PPN functional connectivity can be a marker for exercise-induced motor improvement in PD.

Exercise Management Using a Mobile App in Patients With Parkinsonism: Prospective, Open-Label, Single-Arm Pilot Study

Background

Patients with parkinsonism have higher inactivity levels than the general population, and this results in increased comorbidities. Although exercise has benefits for motor function and quality of life (QOL) in patients with parkinsonism, these patients face many barriers to exercise participation, such as lack of motivation, fatigue, depression, and time constraints. Recently, the use of mobile apps has been highlighted as a remote exercise management strategy for patients with chronic diseases.

Objective

This study aimed to evaluate the effects of home-based exercise management with a customized mobile app on the exercise amount, physical activity, and QOL of patients with parkinsonism.

Methods

This was a prospective, open-label, single-arm pilot study. The therapist installed the app in the smartphones of the participants and educated them on how to use the app. The therapist developed an individualized multimodal exercise program that consisted of stretching, strengthening, aerobic, balance and coordination, and oral-motor and vocal exercises. Participants were encouraged to engage in an 8-week home-based exercise program delivered through a customized app. The alarm notifications of the app provided reminders to exercise regularly at home. The primary outcome was the exercise amount. The secondary outcomes were assessed using the International Physical Activity Questionnaire (IPAQ), Parkinson’s Disease Questionnaire-39 (PDQ-39), and Geriatric Depression Scale (GDS). The usability of the customized app was assessed using a self-report questionnaire.

Results

A total of 21 participants with parkinsonism completed the intervention and assessment between September and December 2020 (mean age: 72 years; women: 17/21, 81%; men: 4/21, 19%). The participants reported a significant increase in the total amount of exercise (baseline: mean 343.33, SD 206.70 min/week; 8-week follow-up: mean 693.10, SD 373.45 min/week; P<.001) and in the amount of each exercise component, including stretching, strengthening, balance and coordination, and oral-motor and vocal exercise after 8 weeks. Analysis of the secondary outcomes revealed significant improvements in the IPAQ (P=.006), PDQ-39 (P=.02), and GDS (P=.04) scores. The usability of the program with the mobile app was verified based on the positive responses such as “intention to use” and “role expectation for rehabilitation.”

Conclusions

Exercise management with a customized mobile app may be beneficial for improving exercise adherence, physical activity levels, depression management, and QOL in patients with parkinsonism. This remotely supervised technology-based, reinforcing, and multimodal exercise management strategy is recommended for use in patients with parkinsonism. In addition, this program proved useful as an alternative exercise management strategy during the COVID-19 pandemic when patients with Parkinson disease were less physically active than before and showed aggravation of symptoms. However, additional clinical trials are needed to evaluate the efficacy of this exercise program in a large population and to confirm its disease-modifying effects.

Physical exercise increases the production of tyrosine hydroxylase and CDNF in the spinal cord of a Parkinson's disease mouse model

Previous research advocates that exercise is a non-pharmacological therapy for Parkinson's disease (PD). However, few studies have investigated the effects of exercise on central nervous system structures other than the nigrostriatal pathway by using PD animal models. This study investigated the effects of exercise on tyrosine hydroxylase (TH)- and cerebral dopamine neurotrophic factor (CDNF)-containing spinal-cord neurons. Male Swiss mice were divided into 4 groups: sedentary control (SEDCONT), exercise control (EXERCONT), sedentary Parkinson (SEDPD), and exercise Parkinson (EXERPD). The PD groups were submitted to a surgical procedure for stereotaxic bilateral injection of 6-hydroxydopamine into the striatum. TH- and CDNF-containing spinal-cord neurons were evaluated in all groups, using immunohistochemistry and western-blotting. TH content in the ventral horn differed notably between the SEDPD and EXERPD groups. CDNF content was highest in the EXERPD group. SEDPD and EXERPD groups differed the most, as shown by immunohistochemistry and western-blotting. The EXERPD group showed the most intense labeling in immunohistochemistry compared to the SEDCONT and EXERCONT groups. Therefore, we showed here that exercise increased the content of both TH and CDNF in the spinal-cord neurons of a bilateral PD mouse model. We may assume that the spinal cord is affected in a PD model, and therefore this central nervous system region deserves more attention from researchers dealing with PD.

Exercise protects synaptic density in a rat model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is characterized by Lewy body and neurite pathology associated with dopamine terminal dysfunction. Clinically, it is associated with motor slowing, rigidity, and tremor. Postural instability and pain are also features. Physical exercise benefits PD patients - possibly by promoting neuroplasticity including synaptic regeneration.

OBJECTIVES

In a parkinsonian rat model, we test the hypotheses that exercise: (a) increases synaptic density and reduces neuroinflammation and (b) lowers the nociceptive threshold by increasing μ-opioid receptor expression.

METHODS

Brain autoradiography was performed on rats unilaterally injected with either 6-hydroxydopamine (6-OHDA) or saline and subjected to treadmill exercise over 5 weeks. [³H]UCB-J was used to measure synaptic vesicle glycoprotein 2A (SV2A) density. Dopamine D2/3 receptor and μ-opioid receptor availability were assessed with [³H]Raclopride and [³H]DAMGO, respectively, while neuroinflammation was detected with the 18kDA translocator protein (TSPO) marker [³H]PK11195. The nociceptive threshold was determined prior to and throughout the exercise protocol.

RESULTS

We confirmed a dopaminegic deficit with increased striatal [³H]Raclopride D2/3 receptor availability and reduced nigral tyrosine hydroxylase immunoreactivity in the ipsilateral hemisphere of all 6-OHDA-injected rats. Sedentary rats lesioned with 6-OHDA showed significant reduction of ipsilateral striatal and substantia nigra [³H]UCB-J binding while [³H]PK11195 showed increased ipsilateral striatal neuroinflammation. Lesioned rats who exercised had higher levels of ipsilateral striatal [³H]UCB-J binding and lower levels of neuroinflammation compared to sedentary lesioned rats. Striatal 6-OHDA injections reduced thalamic μ-opioid receptor availability but subsequent exercise restored binding. Exercise also raised thalamic and hippocampal SV2A synaptic density in 6-OHDA lesioned rats, accompanied by a rise in nociceptive threshold.

CONCLUSION

These data suggest that treadmill exercise protects nigral and striatal synaptic integrity in a rat lesion model of PD - possibly by promoting compensatory mechanisms. Exercise was also associated with reduced neuroinflammation post lesioning and altered opioid transmission resulting in an increased nociceptive threshold.

Effects of task-oriented training combined with aerobic training on serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels in people with Parkinson's disease: A randomized controlled study

INTRODUCTION

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by the death of dopaminergic neurons in the substantia nigra pars compacta. Exercise training, which is incorporated both goal-based training such as task-oriented training (TOT) and aerobic training (AT), has been suggested to induce neuroprotection. However, molecular mechanisms which may underlie exercise-induced neuroprotection are still largely unknown. Thus, the aim of the present study was to investigate the effects of TOT combined with AT (TOT-AT) on serum brain-derived neurotrophic factor (BDNF), glial cell-derived growth factor (GDNF), insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) levels in people with PD (PwPD).

METHODS

Forty PwPD were randomized into 8-week of either exercise group (n = 20) or control group (n = 20). The exercise group received TOT-AT while the control group received only AT. Serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels determined with ELISA were assessed at baseline and after training.

RESULTS

A total of 29 PwPD completed this study. Our results showed no significant change in the serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels in both groups. After the intervention period, no significant difference was observed between the groups regarding the serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels.

CONCLUSION

TOT-AT could not be an effective exercise method for changing serum concentrations of BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β in the rehabilitation of PD.

Parkinson's Disease: A Review from Pathophysiology to Treatment

Parkinson's Disease (PD) is the second most common neurodegenerative disease in the elderly population, with a higher prevalence in men, independent of race and social class; it affects approximately 1.5 to 2.0% of the elderly population over 60 years and 4% for those over 80 years of age. PD is caused by the necrosis of dopaminergic neurons in the substantia nigra, which is the brain region responsible for the synthesis of the neurotransmitter dopamine (DA), resulting in its decrease in the synaptic cleft. The monoamine oxidase B (MAO-B) degrades dopamine, promoting the glutamate accumulation and oxidative stress with the release of free radicals, causing excitotoxicity. The PD symptoms are progressive physical limitations such as rigidity, bradykinesia, tremor, postural instability and disability in functional performance. Considering that there are no laboratory tests, biomarkers or imaging studies to confirm the disease, the diagnosis of PD is made by analyzing the motor features. There is no cure for PD, and the pharmacological treatment consists of a dopaminergic supplement with levodopa, COMT inhibitors, anticholinergics agents, dopaminergic agonists, and inhibitors of MAO-B, which basically aims to control the symptoms, enabling better functional mobility and increasing life expectancy of the treated PD patients. Due to the importance and increasing prevalence of PD in the world, this study reviews information on the pathophysiology, symptomatology as well as the most current and relevant treatments of PD patients.

Cytokine-, Neurotrophin-, and Motor Rehabilitation-Induced Plasticity in Parkinson's Disease

Neuroinflammation and cytokine-dependent neurotoxicity appear to be major contributors to the neuropathology in Parkinson's disease (PD). While pharmacological advancements have been a mainstay in the treatment of PD for decades, it is becoming increasingly clear that nonpharmacological approaches including traditional and nontraditional forms of exercise and physical rehabilitation can be critical adjunctive or even primary treatment avenues. Here, we provide an overview of preclinical and clinical research detailing the biological role of proinflammatory molecules in PD and how motor rehabilitation can be used to therapeutically modulate neuroinflammation, restore neural plasticity, and improve motor function in PD.

Vigorous Aerobic Exercise in the Management of Parkinson Disease: A Systematic Review

OBJECTIVE

To summarize the findings from studies examining the effects of vigorous-intensity aerobic exercise in the management of Parkinson disease. TYPE: Systematic review.

LITERATURE SURVEY

PubMed/MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, SPORTDiscus, and ScienceDirect databases were searched up to May 2020. Reference lists of the included articles were also searched for additional studies. Searches were restricted to English language.

METHODOLOGY

Seven papers, including six studies, five randomized controlled trials and one controlled trial, were identified. The studies examined the effects of vigorous-intensity aerobic exercise in participants with Parkinson disease. Studies in which the minimal intensity required was ≥77% of maximum heart rate, 60% of heart rate reserve or 64% of maximal oxygen uptake met the inclusion criteria. Method appraisal showed a mean score of 5.3 in the Physiotherapy Evidence Database (PEDro) scale.

SYNTHESIS

No statistically significant differences were found between vigorous-intensity aerobic exercise and moderate/low-intensity aerobic exercise for the main outcomes (disease severity and motor function). Only one study concluded a significant higher aerobic fitness in favor of the group that exercised at vigorous intensity compared to the moderate intensity group.

CONCLUSIONS

Vigorous-intensity aerobic exercise has not shown statistically significant improvements in motor and nonmotor impairments in individuals with Parkinson disease as compared to moderate/low-intensity aerobic exercise. Hence, the current evidence is too limited to allow recommendations for clinical practice.

Progressive muscle-strength protocol for the functionality of upper limbs and quality of life in individuals with Parkinson's disease: Pilot study

The effects of physical-therapy intervention on the motor function of upper limbs and the quality of life in patients with Parkinson's disease (PD) are not fully understood. We evaluated the effects of a progressive muscle-strengthening protocol for upper limbs on the functionality and quality of life. Patients were divided into two groups: Intervention (n = 6) and Control (n = 7). Assessment tools used were: Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire, Nine-Hole Peg Test (9HPT), Test d'Évaluation des Membres Supérieurs de Personnes Âgées (TEMPA), 10-Repetition Maximum (10-RM) and handgrip dynamometer, which were applied pre- and post-intervention, with follow-up for one month after the last training session. Only, the Intervention group (post-intervention) showed significant statistical differences, with the following outcomes: UPDRS III (p = 0.042); 9HPT, right (p = 0.028) and left side (p = 0.028); TEMPA for total right side (p = 0.028), left side (p = 0.028) and total bilateral tasks (p = 0.028); TEMPA task 2 - open a jar and take a spoonful of coffee (p = 0.028), task 3 - pick up a pitcher and pour water into a glass for right (p = 0.046) and left side (p = 0.028), task 5 - write on an envelope and stick on a stamp (p = 0.028), and task 6 - shuffle and deal playing cards (p = 0.028). We observed significant statistical differences between groups (post-intervention) for TEMPA task 6 (p = 0.032), total right side (p = 0.032), and total bilateral tasks (p = 0.032). An increase in the maximum load in the post-intervention stage, based on the 10-RM test, was observed on the right (p = 0.003) and left (p = 0.007) sides. Our results showed an improvement in upper-limb functionality in PD patients submitted to progressive muscle-strength training, although not in quality of life.

Comparing the influence of exercise intensity on brain-derived neurotrophic factor serum levels in people with Parkinson's disease: a pilot study

INTRODUCTION

Endogenous brain-derived neurotrophic factor (BDNF) is thought to be protective against the neurodegeneration seen in Parkinson's disease (PD), and is thought to increase during exercise. This has been proposed as a possible mechanism by which exercise improves outcomes for people with PD. We conducted a pilot study to investigate the role of exercise intensity on BDNF levels in people with PD.

METHODS

Participants of early- to mid-stage disease were recruited from a single PD service in north-east England, UK into two separate studies of exercise in PD, one involving moderate-intensity continuous training (MICT) and one involving high-intensity interval training (HIIT), both had control groups. In both the interventions, participants exercise three times per week for 12 weeks. Blood samples were taken for BDNF analysis at the start and end of the first session and the start and end of the final session, with corresponding samples taken in controls.

RESULTS

Data were available for 27 participants (13 intervention, 14 control) in the MICT intervention and 17 (9 intervention, 8 control) in the HIIT intervention. BDNF level did not rise significantly from the start to end of individual sessions. Across the 12 week period, they rose significantly in the HIIT intervention group, but not in controls or the MICT intervention group.

CONCLUSIONS

High-intensity interval training appears to have a greater impact on BDNF than MICT. Future work should directly compare exercise modalities and investigate the impact of BDNF levels on disease progression and quality of life.

Effect of a High-Intensity Tandem Bicycle Exercise Program on Clinical Severity, Functional Magnetic Resonance Imaging, and Plasma Biomarkers in Parkinson's Disease

Rationale: The optimal modality, intensity, duration, frequency, and dose-response of exercise as a therapy for Parkinson's Disease (PD) are insufficiently understood. Objective: To assess the impact of a high-intensity tandem bicycle program on clinical severity, biomarkers, and functional MRI (fMRI) in PD. Methods: A single-center, parallel-group clinical trial was conducted. Thirteen PD patients aged 65 or younger were divided in two groups: a control group and an intervention group that incorporated a cycling program at 80% of each individual's maximum heart rate (HR) (≥80 rpm), three times a week, for 16 weeks. Both groups continued their conventional medications for PD. At baseline and at the end of follow-up, we determined in all participants the Unified Parkinson's Disease Rating Scale, anthropometry, VO₂max, PD biomarkers, and fMRI. Results: VO₂max improved in the intervention group (IG) (+5.7 ml/kg/min), while it slightly deteriorated in the control group (CG) (-1.6 ml/kg/min) (p = 0.041). Mean Unified Parkinson's Disease Rating Scale (UPDRS) went down by 5.7 points in the IG and showed a small 0.9-point increase in the CG (p = 0.11). fMRI showed activation of the right fusiform gyrus during the motor task and functional connectivity between the cingulum and areas of the frontal cortex, and between the cerebellar vermis and the thalamus and posterior temporal gyrus. Plasma brain-derived neurotrophic factor (BDNF) levels increased more than 10-fold in the IG and decreased in the CG (p = 0.028). Larger increases in plasma BDNF correlated with greater decreases in UPDRS (r = -0.58, p = 0.04). Conclusions: Our findings suggest that high-intensity tandem bicycle improves motor function and biochemical and functional neuroimaging variables in PD patients. Trial registration number: ISRCTN 13047118, Registered on February 8, 2018.

Motor-cognitive approach and aerobic training: a synergism for rehabilitative intervention in Parkinson's disease

Parkinson's disease (PD) results in a complex deterioration of motor behavior. Effective pharmacological or surgical treatments addressing the whole spectrum of both motor and cognitive symptoms are lacking. The cumulative functional impairment may have devastating socio-economic consequences on both patients and caregivers. Comprehensive models of care based on multidisciplinary approaches may succeed in better addressing the overall complexity of PD. Neurorehabilitation is a highly promising non-pharmacological intervention for managing PD. The scientific rationale beyond rehabilitation and its practical applicability remain to be established. In the present perspective, we aim to discuss the current evidence supporting integrated motor-cognitive and aerobic rehabilitation approaches for patients with PD while suggesting a practical framework to optimize this intervention in the next future.

BDNF as a Promising Therapeutic Agent in Parkinson's Disease

Brain-derived neurotrophic factor (BDNF) promotes neuroprotection and neuroregeneration. In animal models of Parkinson’s disease (PD), BDNF enhances the survival of dopaminergic neurons, improves dopaminergic neurotransmission and motor performance. Pharmacological therapies of PD are symptom-targeting, and their effectiveness decreases with the progression of the disease; therefore, new therapeutical approaches are needed. Since, in both PD patients and animal PD models, decreased level of BDNF was found in the nigrostriatal pathway, it has been hypothesized that BDNF may serve as a therapeutic agent. Direct delivery of exogenous BDNF into the patient’s brain did not relieve the symptoms of disease, nor did attempts to enhance BDNF expression with gene therapy. Physical training was neuroprotective in animal models of PD. This effect is mediated, at least partly, by BDNF. Animal studies revealed that physical activity increases BDNF and tropomyosin receptor kinase B (TrkB) expression, leading to inhibition of neurodegeneration through induction of transcription factors and expression of genes related to neuronal proliferation, survival, and inflammatory response. This review focuses on the evidence that increasing BDNF level due to gene modulation or physical exercise has a neuroprotective effect and could be considered as adjunctive therapy in PD.

Falls in Synucleinopathies

Parkinson's disease (PD) and other synucleinopathies, namely dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), are common degenerative neurological disorders that share synuclein pathology. Although certain cardinal features of parkinsonism, including bradykinesia and rigidity, respond well to levodopa, axial features, such as gait and balance impairment, are less reliably responsive to dopaminergic therapy and surgical interventions. Consequently, falls are common in PD and other synucleinopathies and are a major contributor toward injury and loss of independence. This underscores the need for appropriate fall risk assessment and implementation of preventative measures in all patients with parkinsonism. The aim of this review is therefore to explore modifiable and non-modifiable risk factors for falls in synucleinopathies. We next review and evaluate the evidence for pharmacological, nonpharmacological, and surgical approaches for fall prevention, and emphasize individualized and multifaceted approaches.

Acute normobaric hypoxia does not affect the simultaneous exercise-induced increase in circulating BDNF and GDNF in young healthy men: A feasibility study

Physical exercise has a neuromodulatory effect on the central nervous system (CNS) partially by modifying expression of neuropeptides produced and secreted by neurons and glial cells, among which the best examined are brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). Because both neurotrophins can cross the brain-blood barrier (BBB), their blood levels indirectly reflect their production in the CNS. Moreover, both neuropeptides are involved in modulation of dopaminergic and serotoninergic system function. Because limited information is available on the effects of exercise to volition exhaustion and acute hypoxia on CNS, BDNF and GDNF formation, the aims of the present study were to verify whether 1) acute exercise to exhaustion in addition to neurons also activates glial cells and 2) additional exposure to acute normobaric moderate hypoxia affects their function. In this feasibility study we measured blood concentrations of BDNF, GDNF, and neuropeptides considered as biomarkers of brain damage (bFGF, NGF, S100B, GFAP) in seven sedentary healthy young men who performed a graded exercise test to volitional exhaustion on a cycle ergometer under normoxic (N) and hypoxic conditions: 2,000 m (H2; FiO2 = 16.6%) and 3,000 m altitude (H3; FiO2 = 14.7%). In all conditions serum concentrations of both BDNF and GDNF increased immediately after cessation of exercise (p<0.01). There was no effect of condition or interaction (condition x time of measurement) and exercise on any of the brain damage biomarkers: bFGF, NGF, S100B, GFAP. Moreover, in N (0<0.01) and H3 (p<0.05) exercise caused elevated serum 5-HT concentration. The results suggest that a graded effort to volitional exhaustion in normoxia, as well as hypoxia, simultaneously activates both neurons and astrocytes. Considering that s100B, GFAP, bFGF, and NGF (produced mainly by astrocytes) are markers of brain damage, it can be assumed that a maximum effort in both conditions is safe for the CNS.

Physical Exercise Improves Aging-Related Changes in Angiotensin, IGF-1, SIRT1, SIRT3, and VEGF in the Substantia Nigra

Dysregulation of tissue renin-angiotensin system (RAS) is involved in oxidative and inflammatory processes observed in major aging-related diseases, including neurodegenerative diseases such as Parkinson's disease (PD). Physical exercise has beneficial effects against aging-related changes, dopaminergic neuron vulnerability, and PD progression. The present study indicates that sedentary aged rats have an increase in activity of the nigral angiotensin (Ang) II/Ang type 1 receptor (AT1) axis (ie, the pro-oxidative pro-inflammatory arm), and a decrease in the activity of the RAS protective arm (ie, Ang II/AT2 and Ang 1-7/Mas receptor axis) in comparison with young rats. In addition, sedentary aged rats showed a decrease in levels of nigral IGF-1, SIRT1, SIRT3, and VEGF. Treadmill running induced a significant increase in levels of IGF-1, SIRT1, SIRT3, and VEGF, as well as an increase in expression of the protective Ang 1-7/Mas axis and inhibition of the Ang II/AT1 axis. The exercise-induced increase in IGF-1 and sirtuins may mediate the effects of exercise on the nigral RAS. However, exercise may induce the increase in VEGF and modulation of RAS activity by different pathways. Exercise, via RAS, contributes to inhibition of the pro-oxidative and proinflammatory state that increase dopaminergic neuron vulnerability and risk of PD with aging.

Health Benefits of Endurance Training: Implications of the Brain-Derived Neurotrophic Factor-A Systematic Review

This article presents a concept that wide expression of brain-derived neurotrophic factor (BDNF) and its receptors (TrkB) in the nervous tissue, evoked by regular endurance training (ET), can cause numerous motor and metabolic adaptations, which are beneficial for human health. The relationships between the training-evoked increase of endogenous BDNF and molecular and/or physiological adaptations in the nervous structures controlling both motor performance and homeostasis of the whole organism have been presented. Due to a very wide range of plastic changes that ET has exerted on various systems of the body, the improvement of motor skills and counteraction of the development of civilization diseases resulting from the posttraining increase of BDNF/TrkB levels have been discussed, as important for people, who undertake ET. Thus, this report presents the influence of endurance exercises on the (1) transformation of motoneuron properties, which are a final element of the motor pathways, (2) reduction of motor deficits evoked by Parkinson disease, and (3) prevention of the metabolic syndrome (MetS). This review suggests that the increase of posttraining levels of BDNF and its TrkB receptors causes simultaneous changes in the activity of the spinal cord, the substantia nigra, and the hypothalamic nuclei neurons, which are responsible for the alteration of the functional properties of motoneurons innervating the skeletal muscles, for the enhancement of dopamine release in the brain, and for the modulation of hormone levels involved in regulating the metabolic processes, responsively. Finally, training-evoked increase of the BDNF/TrkB leads to a change in a manner of regulation of skeletal muscles, causes a reduction of motor deficits observed in the Parkinson disease, and lowers weight, glucose level, and blood pressure, which accompany the MetS. Therefore, BDNF seems to be the molecular factor of pleiotropic activity, important in the modulation processes, underlying adaptations, which result from ET.

Evaluation of exercise-induced modulation of glial activation and dopaminergic damage in a rat model of Parkinson's disease using [11C]PBR28 and [18F]FDOPA PET

Evidence suggests that exercise can modulate neuroinflammation and neuronal damage. We evaluated if such effects of exercise can be detected with positron emission tomography (PET) in a rat model of Parkinson's disease (PD). Rats were unilaterally injected in the striatum with 6-hydroxydopamine (PD rats) or saline (controls) and either remained sedentary (SED) or were forced to exercise three times per week for 40 min (EX). Motor and cognitive functions were evaluated by the open field, novel object recognition, and cylinder tests. At baseline, day 10 and 30, glial activation and dopamine synthesis were assessed by [¹¹C]PBR28 and [¹⁸F]FDOPA PET, respectively. PET data were confirmed by immunohistochemical analysis of microglial (Iba-1) / astrocyte (GFAP) activation and tyrosine hydroxylase (TH). [¹¹C]PBR28 PET showed increased glial activation in striatum and hippocampus of PD rats at day 10, which had resolved at day 30. Exercise completely suppressed glial activation. Imaging results correlated well with post-mortem Iba-1 staining, but not with GFAP staining. [¹⁸F]FDOPA PET, TH staining and behavioral tests indicate that 6-OHDA caused damage to dopaminergic neurons, which was partially prevented by exercise. These results show that exercise can modulate toxin-induced glial activation and neuronal damage, which can be monitored noninvasively by PET.

Asymmetric Dopaminergic Degeneration and Attentional Resources in Parkinson's Disease

Background: Attention is crucial to voluntary perform actions in Parkinson's disease (PD), allowing patients to bypass the impaired habitual motor control. The asymmetrical degeneration of the dopaminergic system could affect the attentional functions. Objective: To investigate the relationship between the asymmetric dopaminergic degeneration and the attentional resources in Parkinsonian patients with right-side (RPD) and left-side (LPD) motor symptoms predominance. Methods: 50 RPD, 50 LPD, and 34 healthy controls underwent visual (V), auditory (A), and multiple choices (MC) reaction time (RTs) tasks. For PD patients, these tasks were performed before and after a 4-week intensive, motor-cognitive rehabilitation treatment (MIRT). The effectiveness of treatment was evaluated assessing Unified Parkinson's disease Rating Scale (UPDRS) III and Timed-up and Go Test (TUG). Results: RTs did not differ between PD patients and healthy controls. Before MIRT, no differences between LPD and RPD patients were observed in RTs (p = 0.20), UPDRS III (p = 0.60), and TUG (p = 0.38). No differences in dopaminergic medication were found between groups (p = 0.44 and p = 0.66 before and after MIRT, respectively). After MIRT, LPD patients showed a significant reduction in MC RTs (p = 0.05), V RTs (p = 0.02), and MC-V RTs. A significant association between changes in RTs and improvements in UPDRS III and TUG was observed in LPD patients. Conclusion: attention does not differ among RPD patients, LPD patients and healthy controls. Only LPD patients improved their performances on attentional tasks after MIRT. We argue that the increased early susceptibility of the left nigrostriatal system to degeneration affects differently the cognitive modifiability and the neuroplastic potential. Our results could provide insight into new therapeutic approaches, highlighting the importance to design different treatments for RPD patients and LPD patients.

A Single Bout of Aerobic Exercise Improves Motor Skill Consolidation in Parkinson's Disease

Background: Motor learning is impaired in Parkinson’s disease (PD), with patients demonstrating deficits in skill acquisition (online learning) and consolidation (offline learning) compared to healthy adults of similar age. Recent studies in young adults suggest that single bouts of aerobic exercise (AEX), performed in close temporal proximity to practicing a new motor task, may facilitate motor skill learning. Thus, we aimed at investigating the effects of a single bout of aerobic cycling on online and offline learning in PD patients.

Methods: 17 PD patients (Hoehn and Yahr 1 – 2.5, age: 64.4 ± 6.2) participated in this crossover study. Immediately prior to practicing a novel balance task, patients either performed 30 min of (i) moderate intensity (60–70% VO_2max) aerobic cycling, or (ii) seated rest (order counterbalanced). The task required patients to stabilize a balance platform (stabilometer) in a horizontal position for 30 s. For each experimental condition, patients performed 15 acquisition trials, followed by a retention test 24 h later. We calculated time in balance (platform within ± 5° from horizontal) for each trial, and analyzed within- and between-subjects differences in skill acquisition (online learning) and skill retention (offline learning) using mixed repeated-measures ANOVA.

Results: We found that the exercise bout had no effect on performance level or online gains during acquisition, despite affecting the time course of skill improvements (larger initial and reduced late skill gains). Aerobic cycling significantly improved offline learning, as reflected by larger 24-h skill retention compared to the rest condition.

Conclusion: Our results suggest that a single bout of moderate-intensity AEX is effective in improving motor skill consolidation in PD patients. Thus, acute exercise may represent an effective strategy to enhance motor memory formation in this population. More work is necessary to understand the underlying mechanisms, the optimal scheduling of exercise, and the applicability to other motor tasks. Further, the potential for patients in later disease stages need to be investigated. The study was a priori registered at ClinicalTrials.gov (NCT03245216).

A Bout of High Intensity Interval Training Lengthened Nerve Conduction Latency to the Non-exercised Affected Limb in Chronic Stroke

Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke.

Design: Randomized cross-over trial.

Setting: Research laboratory in a tertiary rehabilitation hospital.

Participants: Convenience sample of 12 chronic stroke survivors.

Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength).

Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R² = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R² = 0.26 p = 0.02).

Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.

Basal ganglia and beyond: The interplay between motor and cognitive aspects in Parkinson's disease rehabilitation

Parkinson's disease (PD) is characterized by motor and cognitive dysfunctions, affecting the motor behaviour. We summarize evidence that the interplay between motor and cognitive approaches is crucial in PD rehabilitation. Rehabilitation is complementary to pharmacological therapy and effective in reducing the PD disturbances, probably acting by inducing neuroplastic effects. The motor behaviour results from a complex integration between cortical and subcortical areas, underlying the motor, cognitive and motivational aspects of movement. The close interplay amongst these areas makes possible to learn, control and express habitual-automatic actions, which are dysfunctional in PD. The physiopathology of PD could be considered the base for the development of effective rehabilitation treatments. As the volitional action control is spared in early-medium stages of disease, rehabilitative approaches engaging cognition permit to achieve motor benefits and appear to be the most effective for PD. We will point out data supporting the relevance of targeting both motor and cognitive aspects in PD rehabilitation. Finally, we will discuss the role of cognitive engagement in motor rehabilitation for PD.

An 8-Week Low-Intensity Progressive Cycling Training Improves Motor Functions in Patients with Early-Stage Parkinson's Disease

BACKGROUND AND PURPOSE

The effects of high-intensity cycling as an adjuvant therapy for early-stage Parkinson's disease (PD) were highlighted recently. However, patients experience difficulties in maintaining these cycling training programs. The present study investigated the efficacy of cycling at a mild-to-moderate intensity in early-stage PD.

METHODS

Thirteen PD patients were enrolled for 16 serial cycling sessions over a 2-month period. Motor function was assessed using the Unified Parkinson's Disease Rating Scale part III (UPDRS III) and Timed Up and Go (TUG) test as primary outcomes. The Montreal Cognitive Assessment (MoCA), modified Hoehn and Yahr Stage (mHYS), total UPDRS, Falls Efficacy Scale, New Freezing of Gait Questionnaire, Schwab and England Activities of Daily Living, 39-item Parkinson's Disease Questionnaire, Patient Global Impression of Change, and gait performance were assessed as secondary outcomes.

RESULTS

The age and the age at onset were 59.67±7.24 and 53.23±10.26 years (mean±SD), respectively. The cycling cadence was 53.27±8.92 revolutions per minute. The UPDRS III score improved significantly after 8 training sessions (p=0.011) and 16 training sessions (T2) (p=0.001) in the off-state, and at T2 (p=0.004) in the on-state compared to pretraining (T0). The TUG duration was significantly shorter at T2 than at T0 (p<0.05). The findings of MoCA, total UPDRS, double limb support time, and mHYS (in both the off- and on-states) also improved significantly at T2.

CONCLUSIONS

Our pioneer study has demonstrated that a low-intensity progressive cycling exercise can improve motor function in PD, especially akinesia. The beneficial effects were similar to those of high-intensity rehabilitation programs.

Exercise-induced increase in brain-derived neurotrophic factor in human Parkinson's disease: a systematic review and meta-analysis

Background

Animal models of exercise and Parkinson’s disease (PD) have found that the physiologic use of exercise may interact with the neurodegenerative disease process, likely mediated by brain derived neurotrophic factor (BDNF). No reviews so far have assessed the methodologic quality of available intervention studies or have bundled the effect sizes of individual studies on exercise-induced effects on BDNF blood levels in human PD.

Research design and methods

We searched MEDLINE, EMBASE, Cochrane Library, PsycINFO and PubMed from inception to June 2017.

Results

Data aggregated from two randomized controlled trials and four pre-experimental studies with a total of 100 ambulatory patients with idiopathic PD (Hoehn/Yahr ≤3) found improvements in BDNF blood concentration levels in all 6 studies (two RCTs and 4 pre-experimental studies). Pooled BDNF level change scores from the 2 RCTs resulted in a significant homogeneous summary effect size (Standardized Mean Difference 2.06, 95% CI 1.36 to 2.76), and a significant heterogeneous SES for the motor part of the UPDRS-III examination (MD -5.53, 95% CI -10.42 to -0.64). Clinical improvements were noted in all studies using a variety of outcome measures.

Limitations

The evidence-base consists primarily of small studies with low to moderate methodological quality.

Conclusions

This review provides preliminary evidence for the effectiveness of physical exercise treatments for persons with PD on BDNF blood levels. Further research is needed.

Electronic supplementary material

The online version of this article (10.1186/s40035-018-0112-1) contains supplementary material, which is available to authorized users.

Exercise-Induced Neuroprotection of the Nigrostriatal Dopamine System in Parkinson's Disease

Epidemiological studies indicate that physical activity and exercise may reduce the risk of developing Parkinson's disease (PD), and clinical observations suggest that physical exercise can reduce the motor symptoms in PD patients. In experimental animals, a profound observation is that exercise of appropriate timing, duration, and intensity can reduce toxin-induced lesion of the nigrostriatal dopamine (DA) system in animal PD models, although negative results have also been reported, potentially due to inappropriate timing and intensity of the exercise regimen. Exercise may also minimize DA denervation-induced medium spiny neuron (MSN) dendritic atrophy and other abnormalities such as enlarged corticostriatal synapse and abnormal MSN excitability and spiking activity. Taken together, epidemiological studies, clinical observations, and animal research indicate that appropriately dosed physical activity and exercise may not only reduce the risk of developing PD in vulnerable populations but also benefit PD patients by potentially protecting the residual DA neurons or directly restoring the dysfunctional cortico-basal ganglia motor control circuit, and these benefits may be mediated by exercise-triggered production of endogenous neuroprotective molecules such as neurotrophic factors. Thus, exercise is a universally available, side effect-free medicine that should be prescribed to vulnerable populations as a preventive measure and to PD patients as a component of treatment. Future research needs to establish standardized exercise protocols that can reliably induce DA neuron protection, enabling the delineation of the underlying cellular and molecular mechanisms that in turn can maximize exercise-induced neuroprotection and neurorestoration in animal PD models and eventually in PD patients.

Exercise in an animal model of Parkinson's disease: Motor recovery but not restoration of the nigrostriatal pathway

Many clinical studies have reported on the benefits of exercise therapy in patients with Parkinson's disease (PD). Exercise cannot stop the progression of PD or facilitate the recovery of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) (Bega et al., 2014). To tease apart this paradox, we utilized a progressive MPTP (1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine) mouse model in which we initiated 4weeks of treadmill exercise after the completion of toxin administration (i.e., restoration). We found in our MPTP/exercise (MPTP+EX) group several measures of gait function that recovered compared to the MPTP only group. Although there was a small recovery of tyrosine hydroxylase (TH) positive DA neurons in the SNpc and terminals in the striatum, this increase was not statistically significant. These small changes in TH could not explain the improvement of motor function. The MPTP group had a significant 170% increase in the glycosylated/non-glycosylated dopamine transporter (DAT) and a 200% increase in microglial marker, IBA-1, in the striatum. The MPTP+EX group showed a nearly full recovery of these markers back to the vehicle levels. There was an increase in GLT-1 levels in the striatum due to exercise, with no change in striatal BDNF protein expression. Our data suggest that motor recovery was not prompted by any significant restoration of DA neurons or terminals, but rather the recovery of DAT and dampening the inflammatory response. Although exercise does not promote recovery of nigrostriatal DA, it should be used in conjunction with pharmaceutical methods for controlling PD symptoms.

Exercise as a Positive Modulator of Brain Function

Various forms of exercise have been shown to prevent, restore, or ameliorate a variety of brain disorders including dementias, Parkinson's disease, chronic stress, thyroid disorders, and sleep deprivation, some of which are discussed here. In this review, the effects on brain function of various forms of exercise and exercise mimetics in humans and animal experiments are compared and discussed. Possible mechanisms of the beneficial effects of exercise including the role of neurotrophic factors and others are also discussed.

Parkinson Disease: An Evolutionary Perspective

There are two central premises to this evolutionary view of Parkinson disease (PD). First, PD is a specific human disease. Second, the prevalence of PD has increased over the course of human history. Several lines of evidence may explain why PD appears to be restricted to the human species. The major manifestations of PD are the consequence of degeneration in the dopamine-synthesizing neurons of the mesostriatal neuronal pathway. It is of note the enormous expansion of the human dopamine mesencephalic neurons onto the striatum compared with other mammals. Hence, an evolutionary bottle neck was reached with the expansion of the massive nigrostriatal axonal arborization. This peculiar nigral overload may partly explain the selective fragility of the human dopaminergic mesencephalic neurotransmission and the unique presence of PD in humans. On the other hand, several facts may explain the increasing prevalence of PD over the centuries. The apparently low prevalence of PD before the twentieth century may be related to the shorter life expectancy and survival compared to present times. In addition, changes in lifestyle over the course of human history might also account for the increasing burden of PD. Our hunter-gatherers ancestors invested large energy expenditure on a daily basis, a prototypical physical way of life for which our genome remains adapted. Technological advances have led to a dramatic reduction of physical exercise. Since the brain release of neurotrophic factors (including brain-derived neurotrophic factor) is partially exercise related, the marked reduction in exercise may contribute to the increasing prevalence of PD.

Irisin in goldfish (Carassius auratus): Effects of irisin injections on feeding behavior and expression of appetite regulators, uncoupling proteins and lipoprotein lipase, and fasting-induced changes in FNDC5 expression

Irisin is a peptide cleaved from the fibronectin type III domain containing protein 5 (FNDC5) gene that is secreted predominantly by muscle cells but also by other tissues including brain and intestine. In mammals, irisin has been shown to have thermogenic actions via the modulation of uncoupling proteins (UCPs) and to affect feeding and energy homeostasis via actions in brain, adipose tissue, liver, muscle and gastrointestinal tract. To examine the role of irisin on feeding and metabolism in fish, the effects of peripheral (intraperitoneal) injections of irisin on feeding behavior, glucose levels and the mRNA expressions of appetite regulators (cocaine and amphetamine regulated transcript CART, agouti related protein AgRP, orexin), UCPs and lipoprotein lipase LPL and brain factors (brain-derived neurotrophic factor , BDNF and tyrosine hydroxylase TH) were assessed in brain, white muscle and intestine. Irisin injections (100ng/g) induced a decrease in food intake and increases in brain orexin, CART1 and CART2, UCP2, BDNF, muscle UCP2 and intestine LPL mRNA expressions but did not affect blood glucose levels, brain AgRP, TH, UCP1, UCP3 and LPL or muscle UCP1, UCP3 and LPL expressions. A partial goldfish FNDC5 cDNA was isolated and the expressions of FDNC5, UCPs, LPL and BDNF were also compared between fed and fasted fish. Fasting induced decreases FNDC5 mRNA expression in the brain and intestine, but not in muscle. Fasting also induced increases in brain BDNF and LPL expressions and increases in UCP1, UCP2, UCP3 and LPL expressions in muscle. Our result suggest that irisin is an anorexigenic factor in fish and its actions might be in part mediated by appetite-regulating factors such as CART and orexins as well as UCP2 and brain factors such as BDNF.

Multidisciplinary Care in Parkinson's Disease

Parkinson's disease (PD) is now known to be a multisystemic and multipeptide neurodegenerative disorder, whereby patients have an array of symptoms both motor and nonmotor. Nonmotor features of PD have been shown to arise almost 15-20 years prior to motor symptoms and, as such, are also a key determinant to the quality of life of a patient. Therefore, there is increasing evidence that a PD patient's management must encompass a multidisciplinary approach to effectively manage and treat the patient's PD and also their individual symptoms. Therefore, the notion that a PD nurse specialist and a neurologist are the only key players, is no longer the case. Rather, the involvement of speech and language therapist, physiotherapists, palliative care, and others is vital for a patient's recovery and their effective management. Here we discuss a few professions who should ideally be present for each PD patient.

Aerobic Exercise Preserves Olfaction Function in Individuals with Parkinson's Disease

Introduction. Based on anecdotal reports of improved olfaction following aerobic exercise, the aim of this study was to evaluate the effects of an 8-week aerobic exercise program on olfaction function in individuals with Parkinson's disease (PD). Methods. Thirty-eight participants with idiopathic PD were randomized to either an aerobic exercise group (n = 23) or a nonexercise control group (n = 15). The aerobic exercise group completed a 60-minute cycling session three times per week for eight weeks while the nonexercise control group received no intervention. All participants completed the University of Pennsylvania Smell Identification Test (UPSIT) at baseline, end of treatment, and a four-week follow up. Results. Change in UPSIT scores between the exercise and nonexercise groups from baseline to EOT (p = 0.01) and from baseline to EOT+4 (p = 0.02) favored the aerobic exercise group. Individuals in the nonexercise group had worsening olfaction function over time, while the exercise group was spared from decline. Discussion. The difference in UPSIT scores suggested that aerobic exercise may be altering central nervous system pathways that regulate the physiologic or cognitive processes controlling olfaction in individuals with PD. While these results provide promising preliminary evidence that exercise may modify the disease process, further systematic evaluation is necessary.

Microbiota and Neurological Disorders: A Gut Feeling

In the past century, noncommunicable diseases have surpassed infectious diseases as the principal cause of sickness and death, worldwide. Trillions of commensal microbes live in and on our body, and constitute the human microbiome. The vast majority of these microorganisms are maternally derived and live in the gut, where they perform functions essential to our health and survival, including: digesting food, activating certain drugs, producing short-chain fatty acids (which help to modulate gene expression by inhibiting the deacetylation of histone proteins), generating anti-inflammatory substances, and playing a fundamental role in the induction, training, and function of our immune system. Among the many roles the microbiome ultimately plays, it mitigates against untoward effects from our exposure to the environment by forming a biotic shield between us and the outside world. The importance of physical activity coupled with a balanced and healthy diet in the maintenance of our well-being has been recognized since antiquity. However, it is only recently that characterization of the host-microbiome intermetabolic and crosstalk pathways has come to the forefront in studying therapeutic design. As reviewed in this report, synthetic biology shows potential in developing microorganisms for correcting pathogenic dysbiosis (gut microbiota-host maladaptation), although this has yet to be proven. However, the development and use of small molecule drugs have a long and successful history in the clinic, with small molecule histone deacetylase inhibitors representing one relevant example already approved to treat cancer and other disorders. Moreover, preclinical research suggests that epigenetic treatment of neurological conditions holds significant promise. With the mouth being an extension of the digestive tract, it presents a readily accessible diagnostic site for the early detection of potential unhealthy pathogens resident in the gut. Taken together, the data outlined herein provide an encouraging roadmap toward important new medicines and companion diagnostic platforms in a wide range of therapeutic indications.