Aerobic exercise for Alzheimer's disease: A randomized controlled pilot trial

Efficacy of exercise rehabilitation for managing patients with Alzheimer's disease

Alzheimer's disease (AD) is a progressive and degenerative neurological disease characterized by the deterioration of cognitive functions. While a definitive cure and optimal medication to impede disease progression are currently unavailable, a plethora of studies have highlighted the potential advantages of exercise rehabilitation for managing this condition. Those studies show that exercise rehabilitation can enhance cognitive function and improve the quality of life for individuals affected by AD. Therefore, exercise rehabilitation has been regarded as one of the most important strategies for managing patients with AD. Herein, we provide a comprehensive analysis of the currently available findings on exercise rehabilitation in patients with AD, with a focus on the exercise types which have shown efficacy when implemented alone or combined with other treatment methods, as well as the potential mechanisms underlying these positive effects. Specifically, we explain how exercise may improve the brain microenvironment and neuronal plasticity. In conclusion, exercise is a cost-effective intervention to enhance cognitive performance and improve quality of life in patients with mild to moderate cognitive dysfunction. Therefore, it can potentially become both a physical activity and a tailored intervention. This review may aid the development of more effective and individualized treatment strategies to address the challenges imposed by this debilitating disease, especially in low- and middle-income countries.

Effects of Aerobic Exercise on Executive and Memory Functions in Patients With Alzheimer's Disease: A Systematic Review

BACKGROUND

Alzheimer's disease threatens the health of older adults, particularly by disrupting executive and memory functions, and many studies have shown that aerobic exercise prevents and improves the symptoms associated with the disease.

OBJECTIVE

The objective was to systematically review the effects of aerobic exercise on executive and memory functions in patients with Alzheimer's disease and to determine the effect factors and mechanisms of the design of aerobic exercise intervention programs.

METHOD

Relevant literature was searched in three databases (PubMed, Web of Science, and EBSCO) from January 1, 2014 to March 1, 2023, using a subject-word search method. Data on 10 items, including author and country, were extracted from the literature after screening. The quality of the literature was evaluated using the Physiotherapy Evidence Database scale, and a systematic review was performed.

RESULTS

Twelve papers from seven countries were ultimately included, embodying 11 randomized controlled trials and one study with a repeated-measures design. The overall quality of the studies was good as 657 study participants, aged 45 years and older who had varying degrees of Alzheimer's disease and significant symptoms, were included. Aerobic exercise was found to have a significant positive impact on executive and memory functions in people with Alzheimer's disease.

CONCLUSION

The effects of aerobic exercise on aspects of executive function were mainly characterized by improvements in inhibitory control, working memory, and cognitive flexibility, whereas the effects on aspects of memory function were mainly characterized by improvements in logical memory, situational memory, and short-term memory.

Lifestyle Empowerment for Alzheimer's Prevention Prescribed by Physicians: Methods and Adaptations to COVID-19

The health care system is insufficiently capitalizing on the benefits of physical exercise in America's aging population. Few tools exist to help clinicians incorporate physical activity into their clinical care, while barriers limit older adults from initiating and maintaining exercise programs. The Lifestyle Empowerment for Alzheimer's Prevention (LEAP! Rx) Program has been designed to support providers and participants in lifestyle change. LEAP! Rx uses two forms of participant enrollment: physician referrals through electronic health records and self-referrals to test the efficacy of delivering a community-based exercise and healthy lifestyle program to older adults. After referral into the program, participants are randomized to receive the LEAP! Rx Program or are placed in a standard-of-care group to receive the program later. The LEAP! Rx program consists of a personalized and structured exercise program, lifestyle education, and mobile health monitoring. This includes a 12-week Empowerment phase with coaching and supervised exercise training, followed by a 40-week Lifestyle phase with intermittent supervised exercise and coaching. Lifestyle education includes monthly, evidence-based classes on optimal aging. The evaluation of LEAP! Rx focuses on 1) the assessment of implementation and scalability of the LEAP!Rx Program for clinicians and patients 2) the effect of the LEAP! Rx Program on cardiorespiratory fitness, 3) the impact of the LEAP! Rx Program on secondary intervention outcome measures of chronic disease risk factors, including insulin resistance, body composition, and lipids. If successful, this study's findings could advance future healthcare practices, providing a new and practical approach to aging and chronic disease prevention.

A review of the application of exercise intervention on improving cognition in patients with Alzheimer's disease: mechanisms and clinical studies

Alzheimer's disease (AD) is the most common form of dementia, leading to sustained cognitive decline. An increasing number of studies suggest that exercise is an effective strategy to promote the improvement of cognition in AD. Mechanisms of the benefits of exercise intervention on cognitive function may include modulation of vascular factors by affecting cardiovascular risk factors, regulating cardiorespiratory health, and enhancing cerebral blood flow. Exercise also promotes neurogenesis by stimulating neurotrophic factors, affecting neuroplasticity in the brain. Additionally, regular exercise improves the neuropathological characteristics of AD by improving mitochondrial function, and the brain redox status. More and more attention has been paid to the effect of Aβ and tau pathology as well as sleep disorders on cognitive function in persons diagnosed with AD. Besides, there are various forms of exercise intervention in cognitive improvement in patients with AD, including aerobic exercise, resistance exercise, and multi-component exercise. Consequently, the purpose of this review is to summarize the findings of the mechanisms of exercise intervention on cognitive function in patients with AD, and also discuss the application of different exercise interventions in cognitive impairment in AD to provide a theoretical basis and reference for the selection of exercise intervention in cognitive rehabilitation in AD.

Evidence mapping and quality assessment of systematic reviews on exercise intervention for Alzheimer's disease

BACKGROUND

A significant body of literature suggests that exercise can reverse cognitive impairment and ameliorate somatic function in patients with Alzheimer's disease (AD). Systematic reviews (SRs), a common approach of evidence-based medicine, concentrate on a specific issue of a research area. The objective of this work is to provide an overview of existing evidence on the effects of exercise intervention in AD patients and report related health outcomes by reviewing SRs.

METHODS

SRs on exercise intervention in AD patients were retrieved from the PubMed, the Cochrane Library, CBMdisc, Scopus, Web of Science, Embase (via Ovid), China National Knowledge Infrastructure, and WanFang databases from the time of inception to February 2023. The quality of the SRs was evaluated utilizing the A Measurement Tool to Assess Systematic Review 2 (AMSTAR 2) checklist. The results were reported according to the population-intervention-comparison-outcome (PICO) framework and the corresponding evidence mapping was illustrated in tables and bubble plots.

RESULTS

A total of 26 SRs met the eligibility criteria. In terms of methodological quality, 10 SRs were rated as "critically low", 13 SRs were rated as "low", and 3 SRs were rated as "moderate". Exercise was found to exert a beneficial effect on cognitive function, functional independence, physical function, and neuropsychiatric symptoms in patients with AD.

CONCLUSION

Exercise intervention benefits AD patients mainly by improving cognitive function, physical function, functional independence, and neuropsychiatric symptoms. However, due to the low-to-moderate methodology of most SRs included in this analysis, further investigations are required to support our current findings.

Effectiveness of Simultaneous Combined Intervention for Enhancing Cognitive Function in Patients with Moderate Alzheimer's Disease

Background

The evidence supporting the effectiveness of combined interventions in Alzheimer's disease (AD) patients remains inconclusive.

Objective

The aim of this study was to evaluate the mid- and long-term effectiveness of physical training, alone or combined with cognitive games, on cognitive performance in patients with moderate AD.

Methods

Seventy-nine AD patients (≈73% females, age of ≈70±1 years) were randomly divided into three groups: aerobic-based training (AT-group, n = 27), aerobic-based training plus cognitive games (ACT-group, n = 25), and a control group engaged in reading (CG, n = 26), two sessions per week. Cognitive performance was evaluated at the start, 4th week (W4), end of the 8th week (W8), and after a 4-week detraining period (W12), using problem-solving (Tower-of-Hanoi), selective attention (Stroop-test), and working memory (Digit-Span-test) assessments. Stress levels and quality of life were also evaluated.Results:: Aerobic and combined training induced a positive effect on all cognitive functions tested at W4 (except problem-solving) and W8 (all p < 0.001) with greater improvements in working-memory and problem-solving in ACT-group (p < 0.05). Depression levels also decreased significantly, and quality of life improved at W8 (p < 0.001) in both groups. After 4 weeks of detraining, the beneficial effect of AT and ACT was still observed. The CG did not show any significant improvements at all time points.Conclusions:: Physical and cognitive interventions appear effective for improving cognitive-functions, quality-of-life, and reducing depression in AD patients. Combined training emerges as a more effective strategy to mitigate AD progression. Further research is necessary to validate these results and explore their potential for preventing early cognitive decline.

The impact of physical exercise on hippocampal atrophy in mild cognitive impairment and Alzheimer's disease: a meta-analysis

Physical activity (PA) is a promising therapeutic for Alzheimer's disease (AD). Only a handful of meta-analyses have studied the impact of PA interventions on regional brain volumes, and none to date has solely included studies on effect of PA on regional brain volumes in individuals with cognitive impairment (CI). In this meta-analysis, we examined whether there is support for the hypothesis that PA interventions positively impact hippocampal volume (HV) in individuals with CI. We also assessed whether the level of CI [mild CI (MCI) vs. AD] impacted this relationship. We identified six controlled trials that met inclusion criteria. These included 236 participants with AD, MCI, or preclinical AD. Data were extracted and analyzed following Cochrane guidelines. We used a random-effects model to estimate the mean change in HV pre- and post-exercise intervention. Forest plots, Hedges' g funnel plots, and Egger's test were used to assess unbiasedness and visualize intervention effects, and Tau 2 , Cochran's Q, and I 2 were calculated to assess heterogeneity. The primary analysis revealed a significant positive effect of PA on total HV. However, sub-group analyses indicated a significant preservation of HV only in individuals with MCI, but not in those with AD. Egger's test indicated no evidence of publication bias. Subgroup analyses also revealed significant heterogeneity only within the MCI cohort for the total and left HV. PA demonstrated a moderate, significant effect in preserving HV among individuals with MCI, but not AD, highlighting a therapeutic benefit, particularly in earlier disease stages.

The newly discovered glymphatic system: the missing link between physical exercise and brain health?

Dementias are responsible for the most frequent neurodegenerative diseases and the seventh leading cause of death worldwide. As a result, there is a growing effort by the neuroscientific community to understand the physiopathology of neurodegenerative diseases, including how to alleviate the effects of the cognitive decline by means of non-pharmacological therapies (e.g., physical exercise). Studies have shown that exercise can improve aspects of brain health related to cognition. However, there still needs to be more knowledge regarding the mechanisms controlling these relationships, and a newly discovered cleansing system in the brain, named the glymphatic system, can be the missing link in this mechanism. The objective of this paper is to review recent findings regarding the potential impacts of physical exercise on the glymphatic system and its implications for the onset of neurodegenerative diseases. Additionally, considering the close interplay between exercise and sleep quality, we aim to explore how sleep patterns may intersect with exercise-induced effects on glymphatic function, further elucidating the complex relationship between lifestyle factors and brain health.

Understanding the mechanisms of disease modifying effects of aerobic exercise in people with Alzheimer's disease

Alzheimer's disease (AD) is a very disabling disease. Pathologically, it is characterized by the presence of amyloid plaques and neurofibrillary tangles in the brain that results in neurodegeneration. Its clinical manifestations include progressive memory impairment, language decline and difficulty in carrying out activities of daily living (ADL). The disease is managed using interventions such as pharmacological interventions and aerobic exercise. Use of aerobic exercise has shown some promises in reducing the risk of developing AD, and improving cognitive function and the ability to carry out both basic and instrumental ADL. Although, the mechanisms through which aerobic exercise improves AD are poorly understood, improvement in vascular function, brain glucose metabolism and cardiorespiratory fitness, increase in antioxidant capacity and haemoglobin level, amelioration of immune-related and inflammatory responses, modulation of concentration of circulating Neurotrophins and peptides and decrease in concentration of tau protein and cortisol level among others seem to be the possible mechanisms. Therefore, understanding these mechanisms is important to help characterize the dose and the nature of the aerobic exercise to be given. In addition, they may also help in finding ways to optimize other interventions such as the pharmacological interventions. However, more quality studies are needed to verify the mechanisms.

Effects of Exercise Training on Immune-Related Genes and Pathways in the Cortex of Animal Models of Alzheimer's Disease: A Systematic Review

Background

Alzheimer's disease (AD) is a chronic neurodegenerative disease that affects the immune system due to the accumulation of amyloid-β (Aβ) and tau associated molecular pathology and other pathogenic processes. To address AD pathogenesis, various approaches had been conducted from drug development to lifestyle modification to reduce the prevalence of AD. Exercise is considered a prominent lifestyle modification to combat AD.

Objective

This observation prompted us to review the literature on exercise related to immune genes in the cortex of animal models of AD. We focused on animal model studies due to their prevalence in this domain.

Methods

The systematic review was conducted according to PRISMA standards using Web of Science (WoS) and PubMed databases. Any kind of genes, proteins, and molecular molecules were included in this systematic review. The list of these immune-related molecules was analyzed in the STRING database for functional enrichment analysis.

Results

We found that 17 research studies discussed immune-related molecules and 30 immune proteins. These studies showed that exercise had the ability to ameliorate dysfunction in AD-related pathways, which led to decreasing the expression of microglia-related pathways and Th17-related immune pathways. As a result of decreasing the expression of immune-related pathways, the expression of apoptosis-related pathways was also decreasing, and neuronal survival was increased by exercise activity.

Conclusions

Based on functional enrichment analysis, exercise not only could reduce apoptotic factors and immune components but also could increase cell survival and Aβ clearance in cortex samples. PROSPERO ID: CRD42022326093.

Biomarker Responses to Acute Exercise and Relationship with Brain Blood Flow

BACKGROUND

There is evidence that aerobic exercise is beneficial for brain health, but these effects are variable between individuals and the underlying mechanisms that modulate these benefits remain unclear.

OBJECTIVE

We sought to characterize the acute physiological response of bioenergetic and neurotrophic blood biomarkers to exercise in cognitively healthy older adults, as well as relationships with brain blood flow.

METHODS

We measured exercise-induced changes in lactate, which has been linked to brain blood flow, as well brain-derived neurotrophic factor (BDNF), a neurotrophin related to brain health. We further quantified changes in brain blood flow using arterial spin labeling.

RESULTS

As expected, lactate and BDNF both changed with time post exercise. Intriguingly, there was a negative relationship between lactate response (area under the curve) and brain blood flow measured acutely following exercise. Finally, the BDNF response tracked strongly with change in platelet activation, providing evidence that platelet activation is an important mechanism for trophic-related exercise responses.

CONCLUSIONS

Lactate and BDNF respond acutely to exercise, and the lactate response tracks with changes in brain blood flow. Further investigation into how these factors relate to brain health-related outcomes in exercise trials is warranted.

Alterations in Synaptic Connectivity and Synaptic Transmission in Alzheimer's Disease with High Physical Activity

Background

Alzheimer's disease (AD) is a progressive neurodegeneration disease. Physical activity is one of the most promising modifiable lifestyles that can be effective in slowing down the progression of AD at an early stage.

Objective

Explore the molecular processes impaired in AD that were conversely preserved and enhanced by physical activity.

Methods

Integrated transcriptomic analyses were performed in datasets that contain AD patients and elders with different degrees of physical activity. The changes of the hub genes were validated through analyzing another two datasets. The expression of the hub genes was further detected in the hippocampus and cortexes of APP/PS1 transgenic mice with or without physical activity by Quantitative polymerase chain reaction (qPCR).

Results

Cross-comparison highlighted 195 DEGs displaying opposed regulation patterns between AD and high physical activity (HPA). The common DEGs were predominantly involved in synaptic vesicle recycling and synaptic transmission, largely downregulated in AD patients but upregulated in the elders with HPA. Two key modules and four hub genes that were related to synaptic vesicle turnover were obtained from the PPI network. The expression of these hub genes (SYT1, SYT4, SH3GL2, and AP2M1) was significantly decreased in AD transgenic mice and was reversed by HPA training.

Conclusions

HPA may reverse AD pathology by upregulating a range of synaptic vesicle transport related proteins which might improve the efficiency of synaptic vesicle turnover and facilitate inter-neuronal information transfer. The study provides novel insights into the mechanisms underlining the protective effects of HPA on AD.

Oxidative damage in neurodegeneration: roles in the pathogenesis and progression of Alzheimer disease

Alzheimer disease (AD) is associated with multiple etiologies and pathological mechanisms, among which oxidative stress (OS) appears as a major determinant. Intriguingly, OS arises in various pathways regulating brain functions, and it seems to link different hypotheses and mechanisms of AD neuropathology with high fidelity. The brain is particularly vulnerable to oxidative damage, mainly because of its unique lipid composition, resulting in an amplified cascade of redox reactions that target several cellular components/functions ultimately leading to neurodegeneration. The present review highlights the "OS hypothesis of AD," including amyloid beta-peptide-associated mechanisms, the role of lipid and protein oxidation unraveled by redox proteomics, and the antioxidant strategies that have been investigated to modulate the progression of AD. Collected studies from our groups and others have contributed to unraveling the close relationships between perturbation of redox homeostasis in the brain and AD neuropathology by elucidating redox-regulated events potentially involved in both the pathogenesis and progression of AD. However, the complexity of AD pathological mechanisms requires an in-depth understanding of several major intracellular pathways affecting redox homeostasis and relevant for brain functions. This understanding is crucial to developing pharmacological strategies targeting OS-mediated toxicity that may potentially contribute to slow AD progression as well as improve the quality of life of persons with this severe dementing disorder.

Neuropsychiatric Symptoms are Related to Blood-biomarkers in Major Neurocognitive Disorders

BACKGROUND

Neuropsychiatric symptoms (NPS) are highly prevalent among individuals with major neurocognitive disorders (MNCD).

OBJECTIVE

Here, we characterized blood biomarkers (metabolic, inflammatory, neurotrophic profiles and total antioxidant), body composition, physical fitness and quality of life (QoL) in individuals with MNCD according to NPS.

METHODS

The sample comprised 34 older adults (71.4% women; 74.06±6.03 yrs, with MNCD diagnosis) categorized according to 50th percentile [Low (≤12) or High (≥13)] for NPS (Neuropsychiatric Inventory Questionnaire). Sociodemographic, clinical data, body composition, anthropometric, cognitive assessment (ADAS-Cog), physical fitness (Senior Fitness Test), QoL (QoL-Alzheimer's Disease scale) were evaluated, and blood samples were collected for biochemical analysis.

RESULTS

Low compared to high NPS group showed higher levels of IL-6, IGF-1and neurotrophic zscore (composite of IGF-1, VEGF-1, BDNF). Additionally, low compared to high NPS group have higher QoL, aerobic fitness and upper body and lower body strength.

CONCLUSION

The severity of NPS seems to be related to modified neurotrophic and inflammatory outcomes, lower physical fitness, and poor QoL. Strategies to counteract NPS development may preserve the physical and mental health of individuals with MNCD.

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Current Perspectives: Obesity and Neurodegeneration - Links and Risks

Obesity is increasing in prevalence across all age groups. Long-term obesity can lead to the development of metabolic and cardiovascular diseases through its effects on adipose, skeletal muscle, and liver tissue. Pathological mechanisms associated with obesity include immune response and inflammation as well as oxidative stress and consequent endothelial and mitochondrial dysfunction. Recent evidence links obesity to diminished brain health and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Both AD and PD are associated with insulin resistance, an underlying syndrome of obesity. Despite these links, causative mechanism(s) resulting in neurodegenerative disease remain unclear. This review discusses relationships between obesity, AD, and PD, including clinical and preclinical findings. The review then briefly explores nonpharmacological directions for intervention.

Neuromuscular Dysfunction Precedes Cognitive Impairment in a Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) develops along a continuum that spans years prior to diagnosis. Decreased muscle function and mitochondrial respiration occur years earlier in those that develop AD; however, it is unknown what causes these peripheral phenotypes in a disease of the brain. Exercise promotes muscle, mitochondria, and cognitive health and is proposed to be a potential therapeutic for AD, but no study has investigated how skeletal muscle adapts to exercise training in an AD-like context. Utilizing 5xFAD mice, an AD model that develops ad-like pathology and cognitive impairments around 6 mo of age, we examined in vivo neuromuscular function and exercise adapations (mitochondrial respiration and RNA sequencing) before the manifestation of overt cognitive impairment. We found 5xFAD mice develop neuromuscular dysfunction beginning as early as 4 mo of age, characterized by impaired nerve-stimulated muscle torque production and compound nerve action potential of the sciatic nerve. Furthermore, skeletal muscle in 5xFAD mice had altered, sex-dependent, adaptive responses (mitochondrial respiration and gene expression) to exercise training in the absence of overt cognitive impairment. Changes in peripheral systems, specifically neural communication to skeletal muscle, may be harbingers for AD and have implications for lifestyle interventions, like exercise, in AD.

Comparison of various exercise interventions on cognitive function in Alzheimer's patients: A network meta-analysis

OBJECTIVE

Exercise helps enhance cognitive function in Alzheimer's patients, although the most effective forms of exercise remain unknown.

METHODS

This network meta-analysis was registered in INPLASY (INPLASY202330066). According to predetermined criteria, this investigation comprised randomized controlled studies involving exercise therapies in people with Alzheimer's disease. The exercise intervention was ranked using surface under the cumulative ranking curve (SUCRA) and mean ranking, with the critical goal outcomes being overall cognition, executive function, and memory function.

RESULTS

Resistance exercise is the most likely strategy to be beneficial for slowing down overall cognitive function loss in Alzheimer's patients (72.4%). Additionally, multi-component exercise was the most effective way to improve executive function (30.4%). The only type of exercise that significantly affects memory function is resistance exercise. Memory is the cognitive function that is least responsive to exercise.

CONCLUSION

Resistance exercise may be an efficient intervention for overall cognitive function decline in patients with Alzheimer's and conjointly for their memory function. Multi-component exercise is more effective in improving executive function in patients with Alzheimer's disease.

Alzheimer's disease cortical morphological phenotypes are associated with TOMM40'523-APOE haplotypes

Both the APOE ε4 and TOMM40 rs10524523 ("523") genes have been associated with risk for Alzheimer's disease (AD) and neuroimaging biomarkers of AD. No studies have investigated the relationship of TOMM40'523-APOE ε4 on the structural complexity of the brain in AD individuals. We quantified brain morphology and multiple cortical attributes in individuals with mild cognitive impairment (MCI) and AD, then tested whether APOE ε4 or TOMM40 poly-T genotypes were related to AD morphological biomarkers in cognitively unimpaired (CU) and MCI/AD individuals. We identified several AD-specific phenotypes in brain morphology and found that TOMM40 poly-T short alleles are associated with early, AD-specific brain morphological differences in healthy aging. We observed decreased cortical thickness, sulcal depth, and fractal dimension in CU individuals with the poly-T short alleles. Moreover, in MCI/AD participants, the APOE ε4 (TOMM40 L) individuals had a higher rate of gene-related morphological markers indicative of AD. Our data suggest that TOMM40'523 is associated with early brain structure variations in the precuneus, temporal, and limbic cortices.

Gut-muscle-brain axis: Molecular mechanisms in neurodegenerative disorders and potential therapeutic efficacy of probiotic supplementation coupled with exercise

Increased longevity is often associated with age-related conditions. The most common neurodegenerative disorders in the older population are Alzheimer's disease (AD) and Parkinson's disease (PD), associated with progressive neuronal loss leading to functional and cognitive impairments. Although symptomatic treatments are available, there is currently no cure for these conditions. Gut dysbiosis has been involved in the pathogenesis of AD and PD, thus interventions targeting the "gut-brain axis" could potentially prevent or delay these pathologies. Recent evidence suggests that the skeletal muscle and the gut microbiota can affect each other via the "gut-muscle axis". Importantly, cognitive functions in AD and PD patients significantly benefit from physical activity. In this review, we aim to provide a comprehensive picture of the crosstalk between the brain, the skeletal muscle and the gut microbiota, introducing the concept of "gut-muscle-brain axis". Moreover, we discuss human and animal studies exploring the modulatory role of exercise and probiotics on cognition in AD and PD. Collectively, the findings presented here support the potential benefits of physical activity and probiotic supplementation in AD and PD. Further studies will be needed to develop targeted and multimodal strategies, including lifestyle changes, to prevent or delay the course of these pathologies.

An open-source system for efficient clinical trial support: The COMET study experience

Exercise clinical trials are complex, logistically burdensome, and require a well-coordinated multi-disciplinary approach. Challenges include managing, curating, and reporting on many disparate information sources, while remaining responsive to a variety of stakeholders. The Combined Exercise Trial (COMET, NCT04848038) is a one-year comparison of three exercise modalities delivered in the community. Target enrollment is 280 individuals over 4 years. To support rigorous execution of COMET, the study team has developed a suite of scripts and dashboards to assist study stakeholders in each of their various functions. The result is a highly automated study system that preserves rigor, increases communication, and reduces staff burden. This manuscript describes system considerations and the COMET approach to data management and use, with a goal of encouraging further development and adaptation by other study teams in various fields.

Analysis of Effect of Intensity of Aerobic Exercise on Cognitive and Motor Functions and Neurotrophic Factor Expression Patterns in an Alzheimer's Disease Rat Model

The effect of aerobic exercise at different intensities on Alzheimer's disease (AD) still remains unclear. We investigated the effect of aerobic exercise at different intensities on cognitive and motor functions and neurotrophic factor expression. Thirty-two AD-induced rats were randomly assigned to control (CG), low-intensity (Group I), medium-intensity (Group II), and high-intensity (Group III) exercise groups. Each group, except for the CG, performed aerobic exercise for 20 min a day five times a week. After performing aerobic exercise for 4 weeks, their cognitive and motor functions and neurotrophic factor expression patterns were analyzed and compared between the groups. All variables of cognitive and motor functions and neurotrophic factor expression were significantly improved in Groups I, II, and III compared to those in the CG (p < 0.05). Among the neurotrophic factors, brain-derived neurotrophic factor (BDNF) expression was significantly improved in Group III compared to that in Groups I and II (p < 0.05). In the intra-group comparison of cognitive and motor functions, no significant difference was observed in CG, but the aerobic exercise groups showed improvements. Only Group III showed a significant improvement in the time it took to find eight food items accurately (p < 0.05). Aerobic exercise improved the cognitive and motor functions and neurotrophic factor expression patterns in the AD-induced rat model, with high-intensity aerobic exercise having greater effects on cognitive function and BDNF expression.

Mechanisms of the Beneficial Effects of Exercise on Brain-Derived Neurotrophic Factor Expression in Alzheimer's Disease

Brain-derived neurotrophic factor (BDNF) is a key molecule in promoting neurogenesis, dendritic and synaptic health, neuronal survival, plasticity, and excitability, all of which are disrupted in neurological and cognitive disorders such as Alzheimer's disease (AD). Extracellular aggregates of amyloid-β (Aβ) in the form of plaques and intracellular aggregates of hyperphosphorylated tau protein have been identified as major pathological insults in the AD brain, along with immune dysfunction, oxidative stress, and other toxic stressors. Although aggregated Aβ and tau lead to decreased brain BDNF expression, early losses in BDNF prior to plaque and tangle formation may be due to other insults such as oxidative stress and contribute to early synaptic dysfunction. Physical exercise, on the other hand, protects synaptic and neuronal structure and function, with increased BDNF as a major mediator of exercise-induced enhancements in cognitive function. Here, we review recent literature on the mechanisms behind exercise-induced BDNF upregulation and its effects on improving learning and memory and on Alzheimer's disease pathology. Exercise releases into the circulation a host of hormones and factors from a variety of peripheral tissues. Mechanisms of BDNF induction discussed here are osteocalcin, FNDC5/irisin, and lactate. The fundamental mechanisms of how exercise impacts BDNF and cognition are not yet fully understood but are a prerequisite to developing new biomarkers and therapies to delay or prevent cognitive decline.

Changes in stress pathways as a possible mechanism of aerobic exercise training on brain health: a scoping review of existing studies

Physical activity (PA) in the form of aerobic exercise (AE) preserves and improves neurocognitive function across the lifespan. However, a mechanistic understanding of the pathways by which aerobic exercise impacts brain health is still lacking, particularly with respect to stress-related pathways. One mechanistic hypothesis is that AE improves neurocognitive health in part by modifying circulating levels of stress-related hormones and signaling factors associated with the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS), as commonly measured by the biomarkers cortisol (CORT) and salivary α-amylase (sAA). Thus, this hypothesis predicts that changes in stress biomarkers, such as CORT and sAA, are possible explanatory pathways mediating the positive effects of AE on neurocognitive health. In the present review article, we provide a summary of available studies examining the possibility that exercise-induced changes to stress biomarkers could partly account for exercise-related improvements in neurocognitive health. Our review indicates that despite the intuitive appeal of this hypothesis, there is insufficient evidence available to conclude that chronic and habitual AE affects neurocognitive health by altering stress biomarker pathways. The cross-sectional nature of the majority of reviewed studies highlights the need for well-controlled studies to adequately test this hypothesis.

Does Multicomponent Physical Exercise Training Work for Dementia? Exploring the Effects on Cognition, Neuropsychiatric Symptoms, and Quality of Life

OBJECTIVE

To explore the effects of a multicomponent training (MT) physical exercise intervention in the cognitive function, neuropsychiatric symptoms, and quality of life of older adults with major neurocognitive disorder (NCD).

METHODS

Quasi-experimental controlled trial. Thirty-six individuals (25 female) were equally distributed to an exercise group (aged 74.33 ± 5.87 years) or a control group (aged 81.83 ± 6.18 years). The Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog), the Neuropsychiatric Inventory (NPI) and the Quality of Life - Alzheimer's Disease (QoL-AD) tests were performed before and after the intervention.

RESULTS

There was no clear interaction effect factor of intervention on ADAS-Cog (B = 1.33, 95% CI: -2.61 - 5.28, P = .513), NPI (B = -8.35, 95% CI: -18.48 - 1.72, P = .115), and QoL-AD (B = 2.87, 95% CI: .01 - 5.73, P = .058).

CONCLUSIONS

The 6-month MT physical exercise intervention did not present evidence of slowing down cognitive decline neither improving neuropsychiatric symptomatology, and quality of life of older adults with major NCD. Future studies with larger samples are needed to better understand the impact of physical exercise interventions using MT methodology on specific cognitive abilities, neuropsychiatric symptoms, and quality of life domains.

Modulation of microRNAs through Lifestyle Changes in Alzheimer's Disease

Lifestyle factors, including diet and physical activity (PA), are known beneficial strategies to prevent and delay Alzheimer's disease (AD) development. Recently, microRNAs have emerged as potential biomarkers in multiple diseases, including AD. The aim of this review was to analyze the available information on the modulatory effect of lifestyle on microRNA expression in AD. Few studies have addressed this question, leaving important gaps and limitations: (1) in human studies, only circulating microRNAs were analyzed; (2) in mice studies, microRNA expression was only analyzed in brain tissue; (3) a limited number of microRNAs was analyzed; (4) no human nutritional intervention studies were conducted; and (5) PA interventions in humans and mice were poorly detailed and only included aerobic training. Despite this, some conclusions could be drawn. Circulating levels of let-7g-5p, miR-107, and miR-144-3p were associated with overall diet quality in mild cognitive impairment patients. In silico analysis showed that these microRNAs are implicated in synapse formation, microglia activation, amyloid beta accumulation, and pro-inflammatory pathways, the latter also being targeted by miR-129-5p and miR-192-5p, whose circulating levels are modified by PA in AD patients. PA also modifies miR-132, miR-15b-5p, miR-148b-3p, and miR-130a-5p expression in mice brains, which targets are related to the regulation of neuronal activity, ageing, and pro-inflammatory pathways. This supports the need to further explore lifestyle-related miRNA changes in AD, both as biomarkers and therapeutic targets.

Exercise therapy to prevent and treat Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease in the elderly with dementia, memory loss, and severe cognitive impairment that imposes high medical costs on individuals. The causes of AD include increased deposition of amyloid beta (Aβ) and phosphorylated tau, age, mitochondrial defects, increased neuroinflammation, decreased synaptic connections, and decreased nerve growth factors (NGF). While in animals moderate-intensity exercise restores hippocampal and amygdala memory through increased levels of p-AKT, p-TrkB, and p-PKC and decreased levels of Aβ, tau phosphorylation, and amyloid precursor proteins (APP) in AD. Aerobic exercise (with an intensity of 50-75% of VO2 max) prevents hippocampal volume reduction, spatial memory reduction, and learning reduction through increasing synaptic flexibility. Exercise training induces the binding of brain-derived neurotrophic factor (BDNF) to TrkB and the binding of NGF to TrkA to induce cell survival and neuronal plasticity. After aerobic training and high-intensity interval training, the increase of VEGF, angiopoietin 1 and 2, NO, tPA, and HCAR1 in cerebral vessels causes increased blood flow and angiogenesis in the cerebellum, motor cortex, striatum, and hippocampus. In the hippocampus, exercise training decreases mitochondrial fragmentation, DRP1, and FIS1, improving OPA1, MFN1, MFN2, and mitochondrial morphology. In humans, acute exercise as an anti-inflammatory condition causes an acute increase in IL-6 and an increase in anti-inflammatory factors such as IL-1RA and IL-10. Moderate-intensity exercise also inhibits inflammatory markers such as IFN-γ, IL-1β, IL-6, CRP, TNF-α, sTNFR1, COX-2, and NF-κB. Aerobic exercise significantly increases plasma levels of BDNF, nerve growth factor, synaptic plasticity, motor activity, spatial memory, and exploratory behavior in AD subjects. Irisin is a myokine released from skeletal muscle during exercise and protects the hippocampus by suppressing Aβ accumulation and promoting hippocampal proliferation through STAT3 signaling. Therefore, combined exercise training such as aerobic training, strength training, balance and coordination training, and cognitive and social activities seems to provide important benefits for people with AD.

Exercise Is Medicine: How Do We Implement It?

Exercise is well known to have beneficial effects on various disease states. In this paper, we broadly describe the fundamental concepts that are shared among various disease states, including obesity, type 2 diabetes (T2D), cardiovascular disease (CVD), heart failure (HF), cancer, and psychological well-being, and the beneficial effects of exercise training within these concepts. We highlight issues involved in implementing exercise recommendations and describe the potential impacts and challenges to medical professionals and patients. Problems are identified and discussed with respect to the future roles of professionals in the current built environment with its limited infrastructure to support current physical activity recommendations.

Alzheimer's disease: a mini-review for the clinician

Alzheimer's disease (AD), the most common form of dementia, is a striking example of the connection between neurophysiological abnormalities and higher-order cognitive deficiencies. Since its initial description in 1906, research into the pathophysiology and etiology of AD has led to the illumination of an incredibly complex set of genetic and molecular mechanisms for the disease's progression, characterized by much more than the neuropathological hallmarks of beta-amyloid (Aβ) plaques and neurofibrillary tangles (NFTs). In this review, findings relating the neurodegeneration present in AD to its clinical presentation and treatment are summarized, with an emphasis on the interconnectedness of disease pathophysiology. Further, diagnostic guidelines are provided based on the National Institute on Aging-Alzheimer's Association (NIA-AA) workgroup's clinical recommendations. Through the dissemination of detailed but digestible open access resources such as this one, we can move towards an increase in the equity and accessibility of education for the modern clinician.

The association between physical activity and cognitive function in the elderly in rural areas of northern China

Background

Physical activity plays an important role in cognitive function in older adults, and the threshold effect and saturation effect between physical activity and cognitive function are unclear.

Objective

The purpose of this study was to explore the threshold effect and saturation effect between physical activity and cognitive function in the elderly.

Methods

The International Physical Activity Questionnaire (IPAQ) was used to measure moderate-intensity physical activity and vigorous-intensity physical activity and total physical activity in older adults. Cognitive function assessment uses the Beijing version of the Montreal Cognitive Assessment Scale (MoCA). The scale consists of seven parts: visual space, naming, attention, language, abstract ability, delayed recall and orientation, for a total of 30 points. The total score of the study participants < 26 was defined as the optimum cutoff point for a definition of mild cognitive impairment (MCI). The multivariable linear regression model was used to initially explore the relationship between physical activity and total cognitive function scores. The logistic regression model was used to assess the relationship between physical activity and cognitive function dimensions and MCI. The threshold effect and saturation effect between the total physical activity and the total cognitive function scores were investigated by smoothed curve fitting.

Results

This cross-sectional survey had a total of 647 participants aged 60 years and older (mean age: 73 years, female: 53.7%). Participants' higher level of physical activity were associated with higher visual space, attention, language, abstract ability, and delayed recall scores (P < 0.05). Physical activity was not statistically associated with naming and orientation. Physical activity was a protective factor for MCI (P < 0.05). Physical activity was positively correlated with total cognitive function scores. There was a saturation effect between total physical activity and total cognitive function scores, and the saturation point was 6546 MET × min/wk.

Conclusion

This study showed a saturation effect between physical activity and cognitive function, and determined an optimal level of physical activity to protect cognitive function. This finding will help update physical activity guidelines based on cognitive function in the elderly.

Effects of physical activity interventions on executive function in older adults with dementia: A meta-analysis of randomized controlled trials

BACKGROUND

To date quantitative meta-analysis with large samples to investigate the effects and potential moderators of physical activity (PA) on executive function (EF) in older adults with dementia is insufficient. Therefore, we conducted this meta-analysis.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

PARTICIPANTS

Old people with Alzheimer's disease (AD) or related dementia of varying types and severity as the primary diagnosis.

METHODS

PubMed, Web of Science, the Cochrane Library and Embase databases were searched for relevant studies published from 01 January, 2010 to 01 March, 2022. The results of executive function were reported in all RCTs. Random-effects meta-analysis was used to calculate the size of effects. Subgroup analyses of three moderators (including the specific sub-domains of EF, exercise prescription variables, and sample characteristics) were performed.

RESULTS

Eighteen RCTs were included with a combined sample size of 1366. Overall, PA interventions improved overall EF (standardized mean difference [SMD]=0.23, 95% confidence interval [CI] 0.05 to 0.41, p<0.05). The EF sub-domain "planning" was significant moderator (SMD=0.31, 95%CI 0.11 to 1.51, p<0.01), but inhibitory control, working memory and cognitive flexibility were not significant. Regarding exercise prescription variables, type of resistance training; moderate intensity; total duration ≤24 weeks and short (once or twice a week) frequency improved overall EF performance. Session length may be a moderator. Regarding sample characteristics, old-old, AD and both dementia and AD had significant benefits.

CONCLUSIONS AND IMPLICATIONS

EF in older adults with AD or related dementia benefited from physical activity, and the benefit was affected by the type, intensity, total duration, frequency of exercise. Physical activity can be an alternative intervention in aging patients with dementia, to improve EF performance or prevent or EF decline.

Geroprotective interventions in the 3xTg mouse model of Alzheimer's disease

Alzheimer's disease (AD) is an age-associated neurodegenerative disease. As the population ages, the increasing prevalence of AD threatens massive healthcare costs in the coming decades. Unfortunately, traditional drug development efforts for AD have proven largely unsuccessful. A geroscience approach to AD suggests that since aging is the main driver of AD, targeting aging itself may be an effective way to prevent or treat AD. Here, we discuss the effectiveness of geroprotective interventions on AD pathology and cognition in the widely utilized triple-transgenic mouse model of AD (3xTg-AD) which develops both β-amyloid and tau pathologies characteristic of human AD, as well as cognitive deficits. We discuss the beneficial impacts of calorie restriction (CR), the gold standard for geroprotective interventions, and the effects of other dietary interventions including protein restriction. We also discuss the promising preclinical results of geroprotective pharmaceuticals, including rapamycin and medications for type 2 diabetes. Though these interventions and treatments have beneficial effects in the 3xTg-AD model, there is no guarantee that they will be as effective in humans, and we discuss the need to examine these interventions in additional animal models as well as the urgent need to test if some of these approaches can be translated from the lab to the bedside for the treatment of humans with AD.

Effectiveness of lifestyle medicine on cognitive functions in mild cognitive impairments and dementia: A systematic review on randomized controlled trials

Mild cognitive impairment (MCI) and dementia are associated with lifestyle risk factors, making lifestyle medicine a potentially viable intervention for people with MCI and dementia. The present study aims to examine the effectiveness of lifestyle medicine on cognitive functions among people with MCI and dementia, by performing a systematic review and meta-analysis on randomized controlled trials (RCT). A systematic literature search was conducted to extract RCTs adopting lifestyle interventions of diet, exercise, and stress management or emotional well-being. Results showed that 65 studies were eligible. Exercise was the most promising lifestyle intervention that improved various cognitive functions among people with MCI and dementia, and was more effective in MCI than in dementia. Interventions on stress management or emotional well-being did not show a significant effect on people with MCI, and the evidence for people with dementia was insufficient to conclude. Similarly, due to the lack of RCTs on a healthy dietary pattern, the effectiveness of diet interventions was not examined. In conclusion, the exercise component of lifestyle medicine can be an effective and clinically significant intervention for protecting people with MCI and dementia against cognitive declines, especially when served as an early intervention at the stage of MCI.

Early-stage Alzheimer's disease: are skeletal muscle and exercise the key?

Alzheimer's disease (AD) is the most common form of dementia affecting approximately 6.5 million people in the United States alone. The development of AD progresses over a span of years to possibly decades before resulting in cognitive impairment and clinically diagnosed AD. The time leading up to a clinical diagnosis is known as the preclinical phase, a time in which recent literature has noted a more severe loss of body mass and more specifically lean muscle mass and strength prior to diagnosis. Mitochondria dysfunction in neurons is also closely associated with AD, and mitochondrial dysfunction has been seen to occur in skeletal muscle with mild cognitive impairment prior to AD manifestation. Evidence from animal models of AD suggests a close link among skeletal muscle mass, mitochondria function, and cognition. Exercise is a powerful stimulus for improving mitochondria function and muscle health, and its benefits to cognition have been suggested as a possible therapeutic strategy for AD. However, evidence for beneficial effects of exercise in AD-afflicted populations and animal models has produced conflicting results. In this mini-review, we discuss these findings and highlight potential avenues for further investigation that may lead to the implementation of exercise as a therapeutic intervention to delay or prevent the development of AD.

Peripheral metabolism of lipoprotein-amyloid beta as a risk factor for Alzheimer's disease: potential interactive effects of APOE genotype with dietary fats

Alzheimer's disease (AD) is a progressive neurodegenerative disorder pathologically characterized by brain parenchymal abundance of amyloid-beta (Aβ) and the accumulation of lipofuscin material that is rich in neutral lipids. However, the mechanisms for aetiology of AD are presently not established. There is increasing evidence that metabolism of lipoprotein-Aβ in blood is associated with AD risk, via a microvascular axis that features breakdown of the blood-brain barrier, extravasation of lipoprotein-Aβ to brain parenchyme and thereafter heightened inflammation. A peripheral lipoprotein-Aβ/capillary axis for AD reconciles alternate hypotheses for a vascular, or amyloid origin of disease, with amyloidosis being probably consequential. Dietary fats may markedly influence the plasma abundance of lipoprotein-Aβ and by extension AD risk. Similarly, apolipoprotein E (Apo E) serves as the primary ligand by which lipoproteins are cleared from plasma via high-affinity receptors, for binding to extracellular matrices and thereafter for uptake of lipoprotein-Aβ via resident inflammatory cells. The epsilon APOE ε4 isoform, a major risk factor for AD, is associated with delayed catabolism of lipoproteins and by extension may increase AD risk due to increased exposure to circulating lipoprotein-Aβ and microvascular corruption.

Effectiveness of physical exercise at improving functional capacity in older adults living with Alzheimer's disease: a systematic review of randomized controlled trials

PURPOSE

To investigate the effects of physical exercise at improving functional capacity in older adults living with Alzheimer's disease (AD).

METHODS

Medline, Embase, Web of Science, The Cochrane Library, Lilacs, and PEDro were searched from inception until January 2021. Randomized controlled trials (RCTs) that reported functional capacity outcomes were included. The evidence was assessed using the GRADE approach.

RESULTS

Thirteen RCTs were included, involving 811 older adults living with AD. Multimodal exercise (ME), aerobic exercise (AE), and resistance exercise (RE) were used. The interventions were mainly supervised by caregivers. The evidence was low and with effect for activities of daily living (ADLs), moderate and with no effect for mobility and very low and with no effect for muscle strength, postural balance and flexibility after treatment with ME, moderate and with no effect for cardiorespiratory function and ADLs after treatment with AE. It was not possible to synthesize any type of evidence for RE.

CONCLUSIONS

Multimodal exercise promotes improvements in functional capacity (ADLs). Therefore, the practice of physical exercise can be recommended for older adults living with AD. The involvement of the caregiver in the physical exercises should also be considered, as it could enhance the benefits of exercise for these older adults.Implications for rehabilitationHealthcare providers with clinical knowledge regarding physical exercise should promote, prescribe and support the daily practice of physical exercises for older adults living with Alzheimer's disease (AD).The involvement of caregivers in home-based physical exercise programs should be considered, as it could enhance the benefits of such programs for these older adults.It is important to consider the degree of cognitive impairment in older adults living with AD when outlining goals for the improvement in functional capacity through physical exercise.Multimodal exercise involving aerobic training, postural balance, muscle strengthening, and flexibility is capable of promoting an improvement in functional capacity (activities of daily living) for these older adults.

The effects of repetitive transcranial magnetic stimulation and aerobic exercise on cognition, balance and functional brain networks in patients with Alzheimer's disease

The purpose of this study was to investigate the effects of high-frequency repetitive Transcranial Magnetic Stimulation (rTMS) and aerobic exercises (AE) in addition to the pharmacological therapy (PT) in Alzheimer's Disease (AD). Twenty-seven patients with AD aged ≥ 60 years were included in the study and divided into 3 groups (rTMS, AE and control). All groups received PT. rTMS group (n = 10) received 20 Hz rTMS over dorsolateral prefrontal cortex (dlPFC) bilaterally and AE group (n = 9) received the structured moderate-intensity AE for 5 consecutive days/week over 2 weeks. Control group (n = 8) only received PT. Cognition, balance, mobility, quality of life (QoL), and resting state functional brain activity were evaluated one week before and one week after the interventions. (ClinicalTrials.gov ID:NCT05102045). Significant improvements were found in executive functions, behavior, and QoL in the rTMS group, in balance and mobility in the AE group, and in the visual memory and behavior in the control group (p < 0.05). Significant differences were found in the behavior in favor of the rTMS group, and balance in favor of the AE group (p < 0.05). There was a significant increase in activation on middle temporal gyrus, intra calcarine, central opercular cortex, superior parietal lobule, and paracingulate cortex in Default Mode Network (DMN) in the rTMS group (p < 0.05). High-frequency rTMS over bilateral dlPFC may improve executive functions and behavior and lead to increased activation in DMN, structured moderate-intensity AE may improve balance and mobility, and PT may improve memory and behaviour compared to pretreatment in AD.

Increased Functional Connectivity of the Precuneus in Individuals with a Family History of Alzheimer's Disease

BACKGROUND

First-degree relatives of individuals with late-onset Alzheimer's disease (AD) have increased risk for AD, with children of affected parents at an especially high risk.

OBJECTIVE

We aimed to investigate default mode network connectivity, medial temporal cortex volume, and cognition in cognitively healthy (CH) individuals with (FH+) and without (FH-) a family history of AD, alongside amnestic mild cognitive impairment (aMCI) and AD individuals, to determine the context and directionality of dysfunction in at-risk individuals. Our primary hypothesis was that there would be a linear decline (CH FH- > CH FH+ > aMCI > AD) within the risk groups on all measures of AD risk.

METHODS

We used MRI and fMRI to study cognitively healthy individuals (n = 28) with and without AD family history (FH+ and FH-, respectively), those with aMCI (n = 31) and early-stage AD (n = 25). We tested connectivity within the default mode network, as well as measures of volume and thickness within the medial temporal cortex and selected seed regions.

RESULTS

As expected, we identified decreased medial temporal cortex volumes in the aMCI and AD groups compared to cognitively healthy groups. We also observed patterns of connectivity across risk groups that suggest a nonlinear relationship of change, such that the FH+ group showed increased connectivity compared to the FH- and AD groups (CH FH+ > CH FH- > aMCI > AD). This pattern emerged primarily in connectivity between the precuneus and frontal regions.

CONCLUSION

These results add to a growing literature that suggests compensatory brain function in otherwise cognitively healthy individuals with a family history of AD.

Aerobic Training and Circulating Neurotrophins in Alzheimer's Disease Patients: A Controlled Trial

OBJECTIVE

to verify the effects of aerobic exercise training in circulating BDNF, VEGF₁₆₅ and IGF-1 plasma levels and cognitive function in Alzheimer's Disease (AD) patients.

METHODS

34 AD patients participated in the study, divided in two groups: Control Group (CG; n = 16) and Training Group (TG; n = 18 - Moderate aerobic training on the treadmill, three times a week, for 12 weeks). BDNF, VEGF_165, and IGF-1 plasma levels were considered as a primary outcome. Secondary outcomes included cognitive functions and aerobic fitness.

RESULTS

After 12 weeks, maintenance of executive functioning in the TG was found, yet no significant changes on circulating neurotrophins levels were identified. For aerobic fitness, there was an increment in TG group.

CONCLUSION

Twelve weeks of aerobic training were neither effective in improving cognitive functioning significantly, nor influential on circulating neurotrophins levels in AD patients.

Relationship of Muscle Apolipoprotein E Expression with Markers of Cellular Stress, Metabolism, and Blood Biomarkers in Cognitively Healthy and Impaired Older Adults

BACKGROUND

Individuals with mild cognitive impairment (MCI) have reduced lipid-stimulated mitochondrial respiration in skeletal muscle. A major risk factor for Alzheimer's disease (AD), the apolipoprotein E4 (APOE4) allele, is implicated in lipid metabolism and is associated with metabolic and oxidative stress that can result from dysfunctional mitochondria. Heat shock protein 72 (Hsp72) is protective against these stressors and is elevated in the AD brain.

OBJECTIVE

Our goal was to characterize skeletal muscle ApoE and Hsp72 protein expression in APOE4 carriers in relationship to cognitive status, muscle mitochondrial respiration and AD biomarkers.

METHODS

We analyzed previously collected skeletal muscle tissue from 24 APOE4 carriers (60y+) who were cognitively healthy (CH, n = 9) or MCI (n = 15). We measured ApoE and Hsp72 protein levels in muscle and phosphorylated tau181 (pTau181) levels in plasma, and leveraged previously collected data on APOE genotype, mitochondrial respiration during lipid oxidation, and VO2 max.

RESULTS

Muscle ApoE (p = 0.013) and plasma pTau181 levels (p < 0.001) were higher in MCI APOE4 carriers. Muscle ApoE positively correlated with plasma pTau181 in all APOE4 carriers (R2 = 0.338, p = 0.003). Hsp72 expression negatively correlated with ADP (R2 = 0.775, p = <0.001) and succinate-stimulated respiration (R2 = 0.405, p = 0.003) in skeletal muscle of MCI APOE4 carriers. Plasma pTau181 negatively tracked with VO2 max in all APOE4 carriers (R2 = 0.389, p = 0.003). Analyses were controlled for age.

CONCLUSION

This work supports a relationship between cellular stress in skeletal muscle and cognitive status in APOE4 carriers.

Best Medicine for Dementia: The Life-Long Defense of the Brain

This review deals with an unwelcome reality about several forms of dementia, including Alzheimer's disease- that these dementias are caused, in part or whole, by the aging of the vasculature. Since the vasculature ages in us all, dementia is our fate, sealed by the realit!ies of the circulation; it is not a disease with a cure pending. Empirically, cognitive impairment before our 7th decade is uncommon and considered early, while a diagnosis in our 11th decade is late but common in that cohort (>40%). Projections from earlier ages suggest that the prevalence of dementia in people surviving into their 12th decade exceeds 80%. We address the question why so few of many interventions known to delay dementia are recognized as therapy; and we try to resolve this few-and-many paradox, identifying opportunities for better treatment, especially pre-diagnosis. The idea of dementia as a fate is resisted, we argue, because it negates the hope of a cure. But the price of that hope is lost opportunity. An approach more in line with the evidence, and more likely to limit suffering, is to understand the damage that accumulates with age in the cerebral vasculature and therefore in the brain, and which eventually gives rise to cognitive symptoms in late life, too often leading to dementia. We argue that hope should be redirected to delaying that damage and with it the onset of cognitive loss; and, for each individual, it should be redirected to a life-long defense of their brain.

Proceedings from the Albert Charitable Trust Inaugural Workshop on 'Understanding the Acute Effects of Exercise on the Brain'

An inaugural workshop supported by "The Leo and Anne Albert Charitable Trust," was held October 4-7, 2019 in Scottsdale, Arizona, to focus on the effects of exercise on the brain and to discuss how physical activity may prevent or delay the onset of aging-related neurodegenerative conditions. The Scientific Program Committee (led by Dr. Jeff Burns) assembled translational, clinical, and basic scientists who research various aspects of the effects of exercise on the body and brain, with the overall goal of gaining a better understanding as to how to delay or prevent neurodegenerative diseases. In particular, research topics included the links between cardiorespiratory fitness, the cerebrovasculature, energy metabolism, peripheral organs, and cognitive function, which are all highly relevant to understanding the effects of acute and chronic exercise on the brain. The Albert Trust workshop participants addressed these and related topics, as well as how other lifestyle interventions, such as diet, affect age-related cognitive decline associated with Alzheimer's and other neurodegenerative diseases. This report provides a synopsis of the presentations and discussions by the participants, and a delineation of the next steps towards advancing our understanding of the effects of exercise on the aging brain.

The effects of exercise programs on cognition, activities of daily living, and neuropsychiatric symptoms in community-dwelling people with dementia—a systematic review

Background

The prevalence of dementia is expected to increase dramatically. Due to a lack of pharmacological treatment options for people with dementia, non-pharmacological treatments such as exercise programs have been recommended to improve cognition, activities of daily living, and neuropsychiatric symptoms. However, inconsistent results have been reported across different trials, mainly because of the high heterogeneity of exercise modalities. Thus, this systematic review aims to answer the questions whether exercise programs improve cognition, activities of daily living as well as neuropsychiatric symptoms in community-dwelling people with dementia.

Methods

Eight databases were searched for articles published between 2016 and 2021 (ALOIS, CENTRAL, CINAHL, Embase, MEDLINE, PsycINFO, PubMed, Web of Science). Randomized controlled trials evaluating the effects of any type of physical activity on cognition, activities of daily living, or neuropsychiatric symptoms in community-dwelling people with a formal diagnosis of dementia were included in this systematic review. Two authors independently assessed eligibility and quality of the studies. The methodology was in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

Results

Eight publications covering seven trials were included in this review with the majority investigating either a combination of strength and aerobic exercise or aerobic exercise alone. This review revealed that there is no clear evidence for the beneficial effects of exercise on cognition. None of the included trials found an impact on activities of daily living. Although different randomized controlled trials reported inconsistent results, one trial indicated that especially aerobic exercise may improve neuropsychiatric symptoms.

Conclusion

Our systematic review did not confirm the impact of exercise on cognition and activities of daily living in community-dwelling people with dementia. The results suggested that aerobic exercise might be effective to reduce neuropsychiatric symptoms. Well-designed trials including only community-dwelling people with a formal diagnosis of dementia, large samples, long-term follow-ups, and detailed description of adherence to the intervention are needed to improve the scientific evidence on the best type of exercise modality.

Trial registration

PROSPERO, CRD42021246598.

The Effect of Aerobic Exercise on Cognitive Function in People with Alzheimer's Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

A growing body of research has examined the effect of aerobic exercise on cognitive function in people with Alzheimer's Disease (AD), but the findings of the available studies were conflicting. The aim of this study was to explore the effect of aerobic exercise on cognitive function in AD patients. Searches were performed in PubMed, Web of Science, and EBSCO databases from the inception of indexing until 12 November 2021. Cochrane risk assessment tool was used to evaluate the methodological quality of the included literature. From 1942 search records initially identified, 15 randomized controlled trials (RCTs) were considered eligible for systematic review and meta-analysis. Included studies involved 503 participants in 16 exercise groups (mean age: 69.2-84 years) and 406 participants (mean age: 68.9-84 years) in 15 control groups. There was a significant effect of aerobic exercise on increasing mini-mental state examination (MMSE) score in AD patients [weighted mean difference (WMD), 1.50 (95% CI, 0.55 to 2.45), p = 0.002]. Subgroup analyses showed that interventions conducted 30 min per session [WMD, 2.52 (95% CI, 0.84 to 4.20), p = 0.003], less than 150 min per week [WMD, 2.10 (95% CI, 0.84 to 3.37), p = 0.001], and up to three times per week [WMD, 1.68 (95% CI, 0.46 to 2.89), p = 0.007] increased MMSE score significantly. In addition, a worse basal cognitive status was associated with greater improvement in MMSE score. Our analysis indicated that aerobic exercise, especially conducted 30 min per session, less than 150 min per week, and up to three times per week, contributed to improving cognitive function in AD patients. Additionally, a worse basal cognitive status contributed to more significant improvements in cognitive function.

Influence of a 12-Month Structured Exercise Program on the Micronutrient-Cognitive Fitness-Physical Association Profiles in Mild Cognitive Impairment

Background

Preventive lifestyle strategies have shown promise to slow down or prevent age-related cognitive decline. However, evidence on the reciprocal longitudinal relationships between nutrition biomarkers and cognitive and physical performance is lacking. Studying nutritional, cognitive, and physical profiles over time may help to overcome this knowledge gap.

Objective

To investigate the relationship of plasma levels of the robust nutritional- and antioxidant defense-related biomarkers carotenoids and tocopherols with both indicators of cognitive and physical performance in persons with mild cognitive impairment (MCI) participating in a structured exercise program.

Methods

Data from 40 participants with MCI of the NeuroExercise study were analyzed. Participants had undergone a blood withdrawal for the analysis of plasma concentrations of six carotenoids, two tocopherols and retinol prior to and after one-year of structured exercise. All participants had undergone a broad spectrum of cognitive and physical performance tests.

Results

Significant associations between lipophilic micronutrients and cognitive/physical measures were observed that were previously found to play a role in cognitive and physical frailty. In particular, lutein, zeaxanthin, and lycopene are confirmed as robust, reliable, and stable indicators of nutritional defense. Importantly, these micronutrients were associated with cognitive measures prior to the physical training program and to a more prominent extent with indicators of motoric function after the physical exercise program.

Conclusion

Specific profiles of lipophilic micronutrients are associated to cognitive performance measures and, especially after a structured exercise program, to indicators of physical performance.

Non-drug Therapies for Alzheimer's Disease: A Review

Alzheimer's disease (AD) is a debilitating disease leading to great social and economic burdens worldwide. During the past decades, increasing understanding of this disease enables dynamic trials for disease interventions. Unfortunately, at present, AD still remains uncurable, and therefore, developing intervention strategies for improving symptoms and slowing down the disease process becomes a practical focus in parallel with searching for a disease-modifying medication. The aim of this review is to summarize the outcomes of AD clinical trials of non-drug therapies published in the past decade, including cognitive-oriented interventions, physical exercise interventions, brain stimulation, as well as nutrition supplementations, to find out the most effective interventions in the category by looking through the primary and secondary outcomes. The outcomes of the trials could be varied with the interventional approaches, the tested cohorts, the settings of observing outcomes, and the duration of follow-ups, which are all discussed in this review. Hence, we hope to provide crucial information for application of these interventions in real-world settings and assist with optimization of clinical trial designs in this area.

Manipulation of the diet-microbiota-brain axis in Alzheimer's disease

Several studies investigating the pathogenesis of Alzheimer's disease have identified various interdependent constituents contributing to the exacerbation of the disease, including Aβ plaque formation, tau protein hyperphosphorylation, neurofibrillary tangle accumulation, glial inflammation, and the eventual loss of proper neural plasticity. Recently, using various models and human patients, another key factor has been established as an influential determinant in brain homeostasis: the gut-brain axis. The implications of a rapidly aging population and the absence of a definitive cure for Alzheimer's disease have prompted a search for non-pharmaceutical tools, of which gut-modulatory therapies targeting the gut-brain axis have shown promise. Yet multiple recent studies examining changes in human gut flora in response to various probiotics and environmental factors are limited and difficult to generalize; whether the state of the gut microbiota in Alzheimer's disease is a cause of the disease, a result of the disease, or both through numerous feedback loops in the gut-brain axis, remains unclear. However, preliminary findings of longitudinal studies conducted over the past decades have highlighted dietary interventions, especially Mediterranean diets, as preventative measures for Alzheimer's disease by reversing neuroinflammation, modifying the intestinal and blood-brain barrier (BBB), and addressing gut dysbiosis. Conversely, the consumption of Western diets intensifies the progression of Alzheimer's disease through genetic alterations, impaired barrier function, and chronic inflammation. This review aims to support the growing body of experimental and clinical data highlighting specific probiotic strains and particular dietary components in preventing Alzheimer's disease via the gut-brain axis.

Meta analysis of aerobic exercise improving intelligence and cognitive function in patients with Alzheimer's disease

OBJECTIVE

Alzheimer's disease (AD) is a neurodegenerative disease. This study aims to explore the intervention and treatment effects of aerobic exercise and different exercise modes on AD through meta-analysis.

METHODS

Using the set inclusion and exclusion criteria, retrieve the China national knowledge infrastructure (CNKI), Wanfang Data Knowledge Service Platform, China Science and Technology Journal Database, Cochrane Library, and PubMed were searched from January 1, 2012, to December 31, 2021. Cochrane risk bias assessment tool was used to evaluate the quality of the included articles, and ReMan5.4.1 was used for forest plot analysis of mini-mental state exam (MMSE) score indicators included in the included articles.

RESULTS

Twelve randomized controlled trials and 795 samples were included. Meta analysis of all articles: I2 = 91%, P ≤ .00001, (MD = 2.95, 95%CI [2.49, 3.40], P ≤ .00001). Meta analysis of 5 fit aerobics groups: I2 = 4%, P = .38, (MD = 1.53, 95%CI [0.72, 2.33], P = .0002); meta-analysis of three spinning groups: I2 = 3%, P = .36, (MD = 1.79, 95%CI [0.29, 3.29], P = .02).

CONCLUSION

Aerobic exercise can effectively improve intellectual and cognitive impairment in AD patients, and for different forms of aerobic exercise, the therapeutic effect of spinning aerobic exercise is better than that of fit aerobics.

Vitamin D, exercise, and immune health in athletes: A narrative review

Vitamin D exerts important extra-skeletal effects, exhibiting an exquisite immune regulatory ability, affecting both innate and adaptive immune responses through the modulation of immunocyte function and signaling. Remarkably, the immune function of working skeletal muscle, which is fully recognized to behave as a secretory organ with immune capacity, is under the tight control of vitamin D as well. Vitamin D status, meaning hormone sufficiency or insufficiency, can push toward strengthening/stabilization or decline of immune surveillance, with important consequences for health. This aspect is particularly relevant when considering the athletic population: while exercising is, nowadays, the recommended approach to maintain health and counteract inflammatory processes, “too much” exercise, often experienced by athletes, can increase inflammation, decrease immune surveillance, and expose them to a higher risk of diseases. When overexercise intersects with hypovitaminosis D, the overall effects on the immune system might converge into immune depression and higher vulnerability to diseases. This paper aims to provide an overview of how vitamin D shapes human immune responses, acting on the immune system and skeletal muscle cells; some aspects of exercise-related immune modifications are addressed, focusing on athletes. The crossroad where vitamin D and exercise meet can profile whole-body immune response and health.