Aerobic-Strength Exercise Improves Metabolism and Clinical State in Parkinson's Disease Patients

Target modulation of glycolytic pathways as a new strategy for the treatment of neuroinflammatory diseases

Neuroinflammation is an innate and adaptive immune response initiated by the release of inflammatory mediators from various immune cells in response to harmful stimuli. While initially beneficial and protective, prolonged or excessive neuroinflammation has been identified in clinical and experimental studies as a key pathological driver of numerous neurological diseases and an accelerant of the aging process. Glycolysis, the metabolic process that converts glucose to pyruvate or lactate to produce adenosine 5'-triphosphate (ATP), is often dysregulated in many neuroinflammatory disorders and in the affected nerve cells. Enhancing glucose availability and uptake, as well as increasing glycolytic flux through pharmacological or genetic manipulation of glycolytic enzymes, has shown potential protective effects in several animal models of neuroinflammatory diseases. Modulating the glycolytic pathway to improve glucose metabolism and ATP production may help alleviate energy deficiencies associated with these conditions. In this review, we examine six neuroinflammatory diseases-stroke, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and depression-and provide evidence supporting the role of glycolysis in their treatment. We also explore the potential link between inflammation-induced aging and glycolysis. Additionally, we briefly discuss the critical role of glycolysis in three types of neuronal cells-neurons, microglia, and astrocytes-within physiological processes. This review highlights the significance of glycolysis in the pathology of neuroinflammatory diseases and its relevance to the aging process.

Potential molecular mechanism of exercise reversing insulin resistance and improving neurodegenerative diseases

Neurodegenerative diseases are debilitating nervous system disorders attributed to various conditions such as body aging, gene mutations, genetic factors, and immune system disorders. Prominent neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Insulin resistance refers to the inability of the peripheral and central tissues of the body to respond to insulin and effectively regulate blood sugar levels. Insulin resistance has been observed in various neurodegenerative diseases and has been suggested to induce the occurrence, development, and exacerbation of neurodegenerative diseases. Furthermore, an increasing number of studies have suggested that reversing insulin resistance may be a critical intervention for the treatment of neurodegenerative diseases. Among the numerous measures available to improve insulin sensitivity, exercise is a widely accepted strategy due to its convenience, affordability, and significant impact on increasing insulin sensitivity. This review examines the association between neurodegenerative diseases and insulin resistance and highlights the molecular mechanisms by which exercise can reverse insulin resistance under these conditions. The focus was on regulating insulin resistance through exercise and providing practical ideas and suggestions for future research focused on exercise-induced insulin sensitivity in the context of neurodegenerative diseases.

Are physical activity levels, cardiorespiratory fitness and peak power associated with Parkinson's disease severity?

INTRODUCTION

Increased physical activity (PA) may slow Parkinson's disease (PD) progression. Associations between markers of PA and PD severity could justify further studies evaluating interventions increasing PA levels in PD. The objectives of the present study were to assess associations between PA, cardiorespiratory fitness (VO2-max), and muscle peak power and measures of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS), the Parkinson's disease questionnaire-39 (PDQ-39), and the four PD hallmark motor symptoms (rigidity, bradykinesia, postural instability, and tremor).

METHODS

Data from 105 people with PD were used. PA was measured for seven consecutive days using accelerometers. Peak power was measured with a linear encoder during a chair rise test, while VO2-max was directly assessed during a graded bicycle test. Analyses included simple and multiple linear regression and hurdle exponential regression.

RESULTS

PA was weakly to moderately associated with MDS-UPDRS II + III, rigidity, bradykinesia, and postural instability, as well as PDQ-39 mobility and activities of daily living sub-scores. VO2-max and peak power were weakly to moderately associated with MDS-UPDRS III, bradykinesia, and postural instability, while peak power was further weakly associated with the MDS-UPDRS II. Lastly, VO2-max was associated with PDQ-39 mobility and activities of daily living sub-scores.

CONCLUSION

PA, VO2-max, and peak power were associated with PD severity, thus highlighting the potential benefits of a physically active lifestyle. Furthermore, PA and VO2-max were associated with PDQ-39 sub-scores. This calls for confirmation of the potential effect of PA on quality of life in PD.

Exercise as medicine in Parkinson's disease

Parkinson's disease (PD) is an incurable and progressive neurological disorder leading to deleterious motor and non-motor consequences. Presently, no pharmacological agents can prevent PD evolution or progression, while pharmacological symptomatic treatments have limited effects in certain domains and cause side effects. Identification of interventions that prevent, slow, halt or mitigate the disease is therefore pivotal. Exercise is safe and represents a cornerstone in PD rehabilitation, but exercise may have even more fundamental benefits that could change clinical practice. In PD, the existing knowledge base supports exercise as (1) a protective lifestyle factor preventing the disease (ie, primary prevention), (2) a potential disease-modifying therapy (ie, secondary prevention) and (3) an effective symptomatic treatment (ie, tertiary prevention). Based on current evidence, a paradigm shift is proposed, stating that exercise should be individually prescribed as medicine to persons with PD at an early disease stage, alongside conventional medical treatment.

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.

Mechanism and Therapeutic Prospect of miRNAs in Neurodegenerative Diseases

MicroRNAs (miRNAs) are the smallest class of noncoding RNAs, which widely exist in animals and plants. They can inhibit translation or overexpression by combining with mRNA and participate in posttranscriptional regulation of genes, resulting in reduced expression of target proteins, affecting the development, growth, aging, metabolism, and other physiological and pathological processes of animals and plants. It is a powerful negative regulator of gene expression. It mediates the information exchange between different cellular pathways in cellular homeostasis and stress response and regulates the differentiation, plasticity, and neurotransmission of neurons. In neurodegenerative diseases, in addition to the complex interactions between genetic susceptibility and environmental factors, miRNAs can serve as a promising diagnostic tool for diseases. They can also increase or reduce neuronal damage by regulating the body's signaling pathways, immune system, stem cells, gut microbiota, etc. They can not only affect the occurrence of diseases and exacerbate disease progression but also promote neuronal repair and reduce apoptosis, to prevent and slow down the development of diseases. This article reviews the research progress of miRNAs on the mechanism and treatment of neurodegenerative diseases in the nervous system. This trial is registered with NCT01819545, NCT02129452, NCT04120493, NCT04840823, NCT02253732, NCT02045056, NCT03388242, NCT01992029, NCT04961450, NCT03088839, NCT04137926, NCT02283073, NCT04509271, NCT02859428, and NCT05243017.

Muscle Strength and Power in People With Parkinson Disease: A Systematic Review and Meta-analysis

BACKGROUND AND PURPOSE

No studies have synthesized the literature regarding mechanical muscle function (ie, strength, power, rate of force development [RFD]) in people with Parkinson disease (PD). Here, we aimed to expand our understanding of mechanical muscle function in people with PD (PwPD) by systematically reviewing (1) the psychometric properties of isokinetic/isometric dynamometry in PD, (2) the literature comparing mechanical muscle function in PwPD with healthy controls (HC), and (3) reported associations between muscle mechanical muscle function and functional capacity and/or disease severity.

METHODS

Systematic literature search in 6 databases. Included studies had to (1) enroll and report data on PwPD, (2) include assessment(s) of psychometric properties (ie, validity, reliability, responsiveness) of isokinetic/isometric dynamometry in PD, and/or (3) assess mechanical muscle function in both PwPD and HC using isokinetic/isometric dynamometry.

RESULTS

A total of 40 studies were included. Aim 1 studies (n = 2) showed high reliability for isometric dynamometry (hip-abductor/dorsiflexor/trunk flexor-extensor/handgrip: intraclass correlations coefficients range = 0.92-0.98). Aim 2 studies (n = 40) showed impaired mechanical muscle function (ie, strength, power, RFD) in PwPD compared with HC (effect sizes range = 0.52-1.89). Aim 3 studies (n = 11) showed weak-to-strong associations between overall and lower extremities muscle strength and functional capacity and/or disease severity outcomes (ie, Unified Parkinson Disease Rating Scale).

DISCUSSION AND CONCLUSIONS

Sparse methodological evidence suggests high reliability when using dynamometry in PwPD. Muscle strength, power, and RFD are impaired in PwPD compared with HC. Muscle strength is associated with functional capacity and disease severity.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A403 ).

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

A genome on shaky ground: exploring the impact of mitochondrial DNA integrity on Parkinson's disease by highlighting the use of cybrid models

Mitochondria play important roles in the regulation of key cellular processes, including energy metabolism, oxidative stress response, and signaling towards cell death or survival, and are distinguished by carrying their own genome (mtDNA). Mitochondrial dysfunction has emerged as a prominent cellular mechanism involved in neurodegeneration, including Parkinson’s disease (PD), a neurodegenerative movement disorder, characterized by progressive loss of dopaminergic neurons and the occurrence of proteinaceous Lewy body inclusions. The contribution of mtDNA variants to PD pathogenesis has long been debated and is still not clearly answered. Cytoplasmic hybrid (cybrid) cell models provided evidence for a contribution of mtDNA variants to the PD phenotype. However, conclusive evidence of mtDNA mutations as genetic cause of PD is still lacking. Several models have shown a role of somatic, rather than inherited mtDNA variants in the impairment of mitochondrial function and neurodegeneration. Accordingly, several nuclear genes driving inherited forms of PD are linked to mtDNA quality control mechanisms, and idiopathic as well as familial PD tissues present increased mtDNA damage. In this review, we highlight the use of cybrids in this PD research field and summarize various aspects of how and to what extent mtDNA variants may contribute to the etiology of PD.

Early implementation of intended exercise improves quality of life in Parkinson's disease patients

OBJECTIVE

Recent data have shown that regular exercise may ameliorate motor symptoms in Parkinson's disease (PD). This study aims to investigate how intended exercise impacts motor and non-movement symptoms of PD.

METHODS

Eighty-eight patients were randomly assigned to an early exercise group (E-EG), late exercise group (L-EG), or a control group (CG) using a randomized delayed-start design. The E-EG carried out a rigorous, formal exercise program for 1 h, twice per week, for 18 months (May 2018-November 2019). The L-EG took part in the exercise program in the final 6-12 months of the study. We assessed outcomes using the Unified Parkinson's Disease Rating Scale (UPDRS), PDQ-39 Questionnaire, Line A test, Line B test, Nine-hole column test, 30 s squat and stand-up test (30 s SST), 10-m walk test (10mW), Balance Evaluation Systems Mini Test (MiniBESTest), FAB, and Time Up and Go Test (TUG).

RESULTS

The patients with PD in the E-EG had lower performance in the UPDRS and Line B test compared to those in the L-EG at post-exercise (p < 0.05). Moreover, the patients with PD in the E-EG had much lower performance in the PDQ-39 and 9-Hole Peg test compared to those in the L-EG at post-exercise (p < 0.01).

CONCLUSION

Implementation of an exercise regimen improved the movement abilities and quality of life in PD patients, especially in the E-EG. This data supports the idea that intended exercise should be implemented as part of the treatment strategy for PD patients as early as possible.

The Role of Exercise in Parkinson's Disease

Parkinson's disease (PD) is a progressive, neurodegenerative disorder of the central nervous system. While it primarily affects motor function, patients eventually develop non-motor symptoms including depression, anxiety, and eventually dementia. Although there is currently no cure, treatment is aimed largely at improving quality of life though medication or surgical techniques to reduce motor symptoms. However, there is vast evidence of the benefits of physical activity as adjunct therapy for Parkinson's disease. In this review, we analyze 31 studies or reviews and highlight the role of exercise and rehabilitation in PD treatment. This study serves to provide clinicians with a comprehensive resource of the wide variety of exercises with proven benefit for patients affected by Parkinson's disease. Specifically, patients report significant improvements in motor function, cognition, mood and sleep habits.

Effects of Short- and Long-Term Aerobic-Strength Training and Determinants of Walking Speed in the Elderly

BACKGROUND/AIMS

Walking speed (WS) is an objective measure of physical capacity and a modifiable risk factor of morbidity and mortality in the elderly. In this study, we (i) determined effects of 3-month supervised aerobic-strength training on WS, muscle strength, and habitual physical activity; (ii) evaluated capacity of long-term (21 months) training to sustain higher WS; and (iii) identified determinants of WS in the elderly.

METHODS

Volunteers (F 48/M 14, 68.4 ± 7.1 years) completed either 3-month aerobic-strength (3 × 1 h/week, n = 48) or stretching (active control, n = 14) intervention (study A). Thirty-one individuals (F 24/M 7) from study A continued in supervised aerobic-strength training (2 × 1 h/week, 21 months) and 6 (F 5/M 1) became nonexercising controls.

RESULTS

Three-month aerobic-strength training increased preferred and maximal WS (10-m walk test, p < 0.01), muscle strength (p < 0.01) and torque (p < 0.01) at knee extension, and 24-h habitual physical activity (p < 0.001), while stretching increased only preferred WS (p < 0.03). Effect of training on maximal WS was most prominent in individuals with baseline WS between 1.85 and 2.30 m·s-1. Maximal WS measured before intervention correlated negatively with age (r = -0.339, p = 0.007), but this correlation was weakened by the intervention (r = -0.238, p = 0.06). WS progressively increased within the first 9 months of aerobic-strength training (p < 0.001) and remained elevated during 21-month intervention (p < 0.01). Cerebellar gray matter volume (MRI) was positively associated with maximal (r = 0.54; p < 0.0001) but not preferred WS and explained >26% of its variability, while age had only minor effect.

CONCLUSIONS

Supervised aerobic-strength training increased WS, strength, and dynamics of voluntary knee extension as well as habitual physical activity in older individuals. Favorable changes in WS were sustainable over the 21-month period by a lower dose of aerobic-strength training. Training effects on WS were not limited by age, and cerebellar cortex volume was the key determinant of WS.

Targeting Mitochondrial Impairment in Parkinson's Disease: Challenges and Opportunities

The underlying pathophysiology of Parkinson's disease is complex, but mitochondrial dysfunction has an established and prominent role. This is supported by an already large and rapidly growing body of evidence showing that the role of mitochondrial (dys)function is central and multifaceted. However, there are clear gaps in knowledge, including the dilemma of explaining why inherited mitochondriopathies do not usually present with parkinsonian symptoms. Many aspects of mitochondrial function are potential therapeutic targets, including reactive oxygen species production, mitophagy, mitochondrial biogenesis, mitochondrial dynamics and trafficking, mitochondrial metal ion homeostasis, sirtuins, and endoplasmic reticulum links with mitochondria. Potential therapeutic strategies may also incorporate exercise, microRNAs, mitochondrial transplantation, stem cell therapies, and photobiomodulation. Despite multiple studies adopting numerous treatment strategies, clinical trials to date have generally failed to show benefit. To overcome this hurdle, more accurate biomarkers of mitochondrial dysfunction are required to detect subtle beneficial effects. Furthermore, selecting study participants early in the disease course, studying them for suitable durations, and stratifying them according to genetic and neuroimaging findings may increase the likelihood of successful clinical trials. Moreover, treatments involving combined approaches will likely better address the complexity of mitochondrial dysfunction in Parkinson's disease. Therefore, selecting the right patients, at the right time, and using targeted combination treatments, may offer the best chance for development of an effective novel therapy targeting mitochondrial dysfunction in Parkinson's disease.

Altered cardiorespiratory regulation during exercise in patients with Parkinson's disease: A challenging non-motor feature

The incidence of Parkinson’s disease is increasing worldwide. The motor dysfunctions are the hallmark of the disease, but patients also experience non-motor impairments, and over 40% of the patients experience coexistent abnormalities, such as orthostatic hypotension. Exercise training has been suggested as a coping resource to alleviate Parkinson’s disease symptoms and delay disease progression. However, the body of knowledge is showing that the cardiovascular response to exercise in patients with Parkinson’s disease is altered. Adequate cardiovascular and hemodynamic adjustments to exercise are necessary to meet the metabolic demands of working skeletal muscle properly. Therefore, since Parkinson’s disease affects parasympathetic and sympathetic branches of the autonomic nervous system and the latter are crucial in ensuring these adjustments are adequately made, the understanding of these responses during exercise in this population is necessary. Several neural control mechanisms are responsible for the autonomic changes in the cardiovascular and hemodynamic systems seen during exercise. In this sense, the purpose of the present work is to review the current knowledge regarding the cardiovascular responses to dynamic and isometric/resistance exercise as well as the mechanisms by which the body maintains appropriate perfusion pressure to all organs during exercise in patients with Parkinson’s disease. Results from patients with Parkinson’s disease and animal models of Parkinson’s disease provide the reader with a well-rounded knowledge base. Through this, we will highlight what is known and not known about how the neural control of circulation is responding during exercise and the adaptations that occur when individuals exercise regularly.

The effectiveness of two different multimodal training modes on physical performance in elderly

The study compared the effect of 12-week multimodal training programme performed twice a week at the regular exercise facility (REF) with the 12-week multimodal training programme performed three times per week as a part of the research programme (EX). Additionally, the study analysed how the experimental training programme affect the physical performance of cognitive healthy and mild cognitive impaired elderly (MCI). The REF training group included 19 elderly (65.00±3.62 years). The experimental training programme combined cognitively healthy (EXH: n=16; 66.3±6.42 years) and age-matched individuals with MCI (EXMCI: n=14; 66.00±4.79 years). 10m maximal walking speed (10mMWS), Five Times Sit-to-Stand Test (FTSS), maximal and relative voluntary contraction (MVC & rel. MVC) were analysed. The REF group improved in 10mMWS (t=2.431, p=.026), the MVC (t=-3.528, p=.002) and relative MVC (t=3.553, p=.002). The EXH group improved in FTSS (t=5.210, P=.000), MVC (t=2.771, p=.018) and relative MVC (t=-3.793, p=.004). EXMCI improved in FTSS (t=2.936, p=.012) and MVC (t=-2.276, p=.040). According to results, both training programmes sufficiently improved walking speed and muscle strength in cognitively healthy elderly. Moreover, the experimental training programme improved muscle strength in MCI elderly.

Treating Patients Like Athletes: Sports Science Applied to Parkinson's Disease

The evidence demonstrating the benefits of exercise is indisputable for healthy subjects, and more recently, it is growing for Parkinson's disease (PD) patients. Due to its easy access, low cost, social facilitation and, above all, the symptomatic effect, clinical exercise may have a profound impact on PD management. Especially considering that in recent decades there have been no major advances from the pharmacological point of view. Despite this, clinical exercise use it stills limited by the existent flaws in the available evidence supporting its use and guiding its prescription as a PD therapeutic intervention. We believe that a approach from the most relevant scientific and clinical fields is crucial to establish the use of clinical exercise in PD patients' routine care. Therefore, in this viewpoint, we aim to highlight the importance of clinical exercise as a therapeutic intervention in PD, and particularly of the benefits of applying sports science principles to potentiate the use of clinical exercise as a therapeutic intervention in PD management.

Evolving concepts on bradykinesia

Bradykinesia is one of the cardinal motor symptoms of Parkinson's disease and other parkinsonisms. The various clinical aspects related to bradykinesia and the pathophysiological mechanisms underlying bradykinesia are, however, still unclear. In this article, we review clinical and experimental studies on bradykinesia performed in patients with Parkinson's disease and atypical parkinsonism. We also review studies on animal experiments dealing with pathophysiological aspects of the parkinsonian state. In Parkinson's disease, bradykinesia is characterized by slowness, the reduced amplitude of movement, and sequence effect. These features are also present in atypical parkinsonisms, but the sequence effect is not common. Levodopa therapy improves bradykinesia, but treatment variably affects the bradykinesia features and does not significantly modify the sequence effect. Findings from animal and patients demonstrate the role of the basal ganglia and other interconnected structures, such as the primary motor cortex and cerebellum, as well as the contribution of abnormal sensorimotor processing. Bradykinesia should be interpreted as arising from network dysfunction. A better understanding of bradykinesia pathophysiology will serve as the new starting point for clinical and experimental purposes.

Acute and regular exercise distinctly modulate serum, plasma and skeletal muscle BDNF in the elderly

Brain-derived neurotrophic factor (BDNF) participates in orchestrating the adaptive response to exercise. However, the importance of transient changes in circulating BDNF for eliciting whole-body and skeletal muscle exercise benefits in humans remains relatively unexplored. Here, we investigated effects of acute aerobic exercise and 3-month aerobic-strength training on serum, plasma and skeletal muscle BDNF in twenty-two sedentary older individuals (69.0 ± 8.0 yrs., 9 M/13F). BDNF response to acute exercise was additionally evaluated in young trained individuals (25.1 ± 2.1 yrs., 3 M/5F). Acute aerobic exercise transiently increased serum BDNF in sedentary (16%, p = .007) but not in trained elderly or young individuals. Resting serum or plasma BDNF was not regulated by exercise training in the elderly. However, subtle training-related changes of serum BDNF positively correlated with improvements in walking speed (R = 0.59, p = .005), muscle mass (R = 0.43, p = .04) and cognitive performance (R = 0.41, p = .05) and negatively with changes in body fat (R = -0.43, p = .04) and triglyceridemia (R = -0.53, p = .01). Individuals who increased muscle BDNF protein in response to 3-month training (responders) displayed stronger acute exercise-induced increase in serum BDNF than non-responders (p = .006). In addition, muscle BDNF protein content positively correlated with type II-to-type I muscle fiber ratio (R = 0.587, p = .008) and with the rate of post-exercise muscle ATP re-synthesis (R = 0.703, p = .005). Contrary to serum, acute aerobic exercise resulted in a decline of plasma BDNF 1 h post-exercise in both elderly-trained (-34%, p = .002) and young-trained individuals (-48%, p = .034). Acute circulating BDNF regulation by exercise was dependent on the level of physical fitness and correlated with training-induced improvements in metabolic and cognitive functions. Our observations provide an indirect evidence that distinct exercise-induced changes in serum and plasma BDNF as well as training-related increase in muscle BDNF protein, paralleled by improvements in muscle and whole-body clinical phenotypes, are involved in the coordinated adaptive response to exercise in humans.

Exercise as a therapeutic intervention for motor and non-motor symptoms in Parkinson's disease: Evidence from rodent models

Parkinson's disease (PD) is characterised by degeneration of dopaminergic neurons of the nigrostriatal pathway, which leads to the cardinal motor symptoms of the disease - tremor, rigidity and postural instability. A number of non-motor symptoms are also associated with PD, including cognitive impairment, mood disturbances and dysfunction of gastrointestinal and autonomic systems. Current therapies provide symptomatic relief but do not halt the disease process, so there is an urgent need for preventative strategies. Lifestyle interventions such as aerobic exercise have shown potential to lower the risk of developing PD and to alleviate both motor and non-motor symptoms. However, there is a lack of large-scale randomised clinical trials that have employed exercise in PD patients. This review will focus on the evidence from studies on rodent models of PD, for employing exercise as an intervention for both motor and non-motor symptoms.

Blunted cardiovascular responses to exercise in Parkinson’s disease patients: role of the muscle metaboreflex

Patients with Parkinson’s disease (PD) exhibit attenuated cardiovascular responses to exercise. The underlying mechanisms that are potentially contributing to these impairments are not fully understood. Therefore, we sought to test the hypothesis that patients with PD exhibit blunted cardiovascular responses to isolated muscle metaboreflex activation following exercise. For this, mean blood pressure, cardiac output, and total peripheral resistance were measured using finger photoplethysmography and the Modelflow method in 11 patients with PD [66 ± 2 yr; Hoehn and Yahr score: 2 ± 1 a.u.; time since diagnosis: 7 ± 1 yr; means ± SD) and 9 age-matched controls (66 ± 3 yr). Measurements were obtained at rest, during isometric handgrip exercise performed at 40% maximal voluntary contraction, and during postexercise ischemia. Also, a cold pressor test was assessed to confirm that blunted cardiovascular responses were specific to exercise and not representative of generalized sympathetic responsiveness. Changes in mean blood pressure were attenuated in patients with PD during handgrip (PD: ∆25 ± 2 mmHg vs. controls: ∆31 ± 3 mmHg; P < 0.05), and these group differences remained during postexercise ischemia (∆17 ± 1 mmHg vs. ∆26 ± 1 mmHg, respectively; P < 0.01). Additionally, changes in total peripheral resistance were attenuated during exercise and postexercise ischemia, indicating blunted reflex vasoconstriction in patients with PD. Responses to cold pressor test did not differ between groups, suggesting no group differences in generalized sympathetic responsiveness. Our results support the concept that attenuated cardiovascular responses to exercise observed in patients with PD are, at least in part, explained by an altered skeletal muscle metaboreflex.

NEW & NOTEWORTHY Patients with Parkinson’s disease (PD) presented blunted cardiovascular responses to exercise. We showed that cardiovascular response evoked by the metabolic component of the exercise pressor reflex is blunted in patients with PD. Furthermore, patients with PD presented similar pressor response during the cold pressor test compared with age-matched controls. Altogether, our results support the hypothesis that attenuated cardiovascular responses to exercise observed in patients with PD are mediate by an altered skeletal muscle metaboreflex.

Feasibility of Aerobic Exercise in the Subacute Phase of Recovery From Traumatic Brain Injury: A Case Series

BACKGROUND AND PURPOSE

Aerobic exercise is as important for individuals with traumatic brain injury (TBI) as for the general population; however, the approach to aerobic training may require some adaptation. The objective of the trial program was to examine the feasibility of introducing aerobic physical exercise programs into the subacute phase of multidisciplinary rehabilitation from moderate to severe TBI, which includes computerized cognitive training.

CASE DESCRIPTION

Five individuals undergoing inpatient rehabilitation with moderate or severe TBIs who also have concomitant physical injuries. All of these individuals were in the subacute phase of recovery from TBIs.

INTERVENTION

An 8-week progressive aerobic physical exercise program. Participants were monitored to ensure that they could both adhere to and tolerate the exercise program. In addition to the physical exercise, individuals were undergoing their standard rehabilitation procedures that included cognitive training. Neuropsychological testing was performed to gain an understanding of each individual's cognitive function.

OUTCOMES

Participants adhered to both aerobic exercise and cognitive training. Poor correlations were noted between heart rate reserve and ratings of perceived effort. Two minor adverse events were reported.

DISCUSSION

Despite concomitant physical injuries and cognitive impairments, progressive aerobic exercise programs seem feasible and well tolerated in subacute rehabilitation from moderate to severe TBI. Findings highlight the difficulty in measuring exercise intensity in this population.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A235).