Physical activity attenuates age-related biomarker alterations in preclinical AD

Physical activity changes during midlife link to brain integrity and amyloid burden

INTRODUCTION

Evidence suggests that midlife physical activity may reduce Alzheimer's disease (AD) risk. In at-risk individuals, we investigated midlife physical activity changes in relation to AD-related pathologies.

METHODS

We included 337 cognitively unimpaired adults with baseline and follow-up physical activity evaluations within 4.07 ± 0.84 years. We performed multiple regressions considering follow-up amyloid-PET burden and MRI-based medial temporal lobe cortical thickness as outcomes. Independent variables encompassed changes in adherence to World Health Organization (WHO)-recommended physical activity levels, activity amounts, and sedentary behavior (no activity reported).

RESULTS

Remaining sedentary was associated with lower cortical thickness compared to doing limited physical activity, maintaining adherence, or becoming adherent to WHO recommendations. Becoming adherent to recommendations was linked to lower amyloid burden compared to becoming non-adherent. Increased activity amounts showed a dose-dependent association with lower amyloid burden.

DISCUSSION

Increasing physical activity and new adherence to WHO recommendations could be key objectives for preventive strategies during midlife.

CLINICAL TRIAL REGISTRATION INFORMATION

Registered at Clinicaltrials.gov (identifier: NCT02485730).

HIGHLIGHTS

Boosting physical activity in midlife may have beneficial effects in preclinical AD. Physical activity increases relate to lower Aβ burden in a dose-dependent manner. Remaining sedentary links to lower cortical thickness in AD-vulnerable structures. New adherence to WHO-recommended physical activity levels may enhance brain health.

Late-midlife lifestyle and brain and cognitive changes in individuals on the AD versus non-AD continuum

INTRODUCTION

We investigated whether a composite measure of late-midlife lifestyle was associated with (1) longitudinal brain changes and (2) cognitive changes when adjusting for these brain changes.

METHODS

We used linear mixed models to examine whether the LIfestyle for BRAin Health (LIBRA) index was associated with changes in tau, white matter hyperintensity, neurodegeneration, and cognition and whether changes were similar in amyloid positive (A+; > 17 Centiloids) and negative participants.

RESULTS

We included 324 individuals from the Wisconsin Registry for Alzheimer's Prevention (39% apolipoprotein E [APOE] ε 4 carrier, 30% A+, prior baseline age 67 [50-75]). The LIBRA index was not associated with biomarker trajectories or the primary cognitive composite outcome trajectory. There were inconsistent effects on secondary domain-specific cognitive trajectories. In contrast, tau and neurodegeneration were strongly associated with cognitive trajectories.

DISCUSSION

In the age-range and disease-range studied, lifestyle did not exhibit a meaningful effect on Alzheimer's disease or vascular biomarker accumulation and was not consistently associated with cognitive trajectories.

Highlights

In this age-range, the LIfestyle for BRAin Health (LIBRA) index was not associated with biomarker trajectories.The LIBRA index was not consistently associated with cognitive trajectories.Effects of lifestyle, if any, may take more time to manifest.

The impact of cardiorespiratory fitness on Alzheimer's disease biomarkers and their relationships with cognitive decline

INTRODUCTION

Relationships between core Alzheimer's disease (AD) biomarker accumulation and cognitive decline are well-established and the literature generally suggests a favorable relationship of cardiorespiratory fitness (CRF) on AD biomarker accumulation and cognition. Differences in risk of biomarker status conversion or accumulation rates by CRF, or their potential interactive relationships with cognitive decline remain largely unknown.

METHODS

Participants (N=533; MeanAGE=65, 70% female) from the Wisconsin Alzheimer's Disease Research Center and the Wisconsin Registry for Alzheimer's Prevention underwent serial blood draws, and cognitive and imaging assessments (MeanFollow-up=6.0 years). PET imaging of amyloid-β (Aβ) and tau (T) and plasma phosphorylated tau-217 (pTau-217) were used to determine biomarker status (+/-). Sex-specific estimated CRF (eCRF) tertiles were created using a validated equation. Kaplan-Meier survival curves and Cox-proportional hazards models characterized the risk of becoming biomarker-positive. Linear mixed effects models estimated associations between baseline eCRF and core AD biomarker accumulation and whether eCRF modified relationships between biomarker accumulation and cognitive decline. Analyses were stratified by biomarker +/- status.

RESULTS

No significant relationships were observed between eCRF and biomarker trajectories. However, those in the high eCRF group who were also Aβ- (HR[95%CI]=0.42[0.20, 0.88]) and pTau-217-(HR[95%CI]=0.45[0.21, 0.97]) at baseline had a significantly lower risk of becoming biomarker-positive. There was a significant attenuation of the detrimental relationship between Aβ accumulation and cognitive decline for those with high eCRF and Aβ+/T+.

DISCUSSION

While CRF did not influence core AD biomarker accumulation trajectories, high CRF did seem to protect against becoming biomarker-positive and attenuate the known deleterious relationship between biomarker accumulation and cognitive decline in Aβ+/T+.

Physical activity and APOE neuropathology score modify the association of age and [11C]-PiB-PET amyloid burden in a cohort enriched with risk for Alzheimer's disease

Background

Physical activity (PA) is a protective factor against amyloid-β (Aβ) accumulation in adults at risk for Alzheimer's disease (AD). This association, however, may differ by apolipoprotein E (APOE) genotype. This work examines interactions between age, PA, and neuropathology-based genetic risk for AD (APOE np ) on Aβ burden in cortical regions sensitive to its accumulation.

Materials and Methods

Included were 388 cognitively unimpaired, older (mean age ± SD = 68.10 ± 7.09; 66% female) participants from the Wisconsin Registry for Alzheimer's Prevention (WRAP) study. The cohort was enriched with both family history of AD at enrollment and a higher overall prevalence of APOE ε4 allele carriage than typically observed in the general population. PA was assessed using a self-reported questionnaire. Aβ burden was measured using Pittsburg Compound B (11C-PiB) PET imaging, which allowed us to derive volume corrected distribution volume ratio (DVR) maps from nine bilateral regions of interest (ROIs) and a global cortical composite score. Linear regression models examined the interactions between age, PA, and APOE np on Aβ burden. Finally, APOE np scores were aggregated according to estimated risk to illustrate the differential effects between active (weekly moderate PA ≥ 150 minutes) and inactive individuals.

Results

Three-way interactions (Age × PA × APOE np ) were significant (all P's ≤ 0.05) for the global cortical composite and six of the examined ROIs (the PPC, ACC, mOFC, SMG, MTG, and STG). Models stratified by APOE np and PA showed greater levels of age-related Aβ accumulation in each of these ROIs, with the greatest effects in inactive participants with high APOE np scores.

Conclusion

Individuals with high APOE np scores who concomitantly engage in suboptimal weekly moderate-intensity PA have greater Aβ burden. These findings underscore how both PA and APOE haplotype play intersect in modifying age-related Aβ burden in brain regions susceptible to its deposition in cognitively unimpaired, older adults at risk for AD.

Older more fit KL-VS heterozygotes have more favorable AD-relevant biomarker profiles

INTRODUCTION

While hallmarked by the accumulation of β-amyloid plaques (Aβ) and neurofibrillary tangles (tau) in the brain, Alzheimer's disease (AD) is a multifactorial disorder that involves additional pathological events, including neuroinflammation, neurodegeneration and synaptic dysfunction. AD-associated biomolecular changes seem to be attenuated in carriers of the functionally advantageous variant of the KLOTHO gene (KL-VSHET). Independently, better cardiorespiratory fitness (CRF) is associated with better health outcomes, both in general and specifically with regard to AD pathology. Here we investigate whether the relationships between CRF (peak oxygen consumption (VO2peak)) and cerebrospinal fluid (CSF) core AD biomarkers and those of neuroinflammation, neurodegeneration, and synaptic dysfunction differ for KL-VSHET compared to non-carriers (KL-VSNC).

METHODS

The cohort, enriched for AD risk, consisted of cognitively unimpaired adults (N=136; MeanAGE(SD)=62.5(6.7)) from the Wisconsin Registry for Alzheimer's Prevention and the Wisconsin Alzheimer's Disease Research Center. Covariate-adjusted (age, sex, parental AD history, APOE4+ status, and age difference between CSF sampling and exercise test) linear models examined the interaction between VO2peak and KLOTHO genotype on core AD biomarker levels in CSF [phosphorylated tau 181 (pTau181), Aβ42/Aβ40, pTau181/Aβ42]. Analyses were repeated for CSF biomarkers of neurodegeneration [total tau (tTau), α-synuclein (α-syn), neurofilament light polypeptide (NfL)], synaptic dysfunction [neurogranin (Ng)], and neuroinflammation [glial fibrillary acidic protein (GFAP), soluble triggering receptor expressed in myeloid cells (sTREM2), chitinase-3-like protein 1 (YKL-40), interleukin 6 (IL-6), S100 calcium-binding protein B (S100B)].

RESULTS

The interaction between VO2peak and KL-VSHET was significant for tTau (P=0.05), pTau181 (P=0.03), Ng (P=0.02), sTREM2 (P=0.03), and YKL-40 (P=0.03), such that lower levels of each biomarker were observed for KL-VSHET who were more fit. No significant KL-VSxVO2peak interactions were observed for Aβ42/Aβ40, pTau181/Aβ42, α-syn, NfL, GFAP, IL-6 or S100B (all Ps>0.09).

CONCLUSIONS

We report a synergistic relationship between KL-VSHET and CRF with regard to pTau181, tTau, Ng, sTREM2 and YKL-40, suggesting a protective role for both KL-VSHET and better cardiovascular fitness against unfavorable AD-related changes. Their potentially shared biological mechanisms will require future investigations.

The relationship between leisure time physical activity patterns, Alzheimer's disease markers and cognition

We assessed the association between leisure time physical activity patterns across 30 years of adulthood with a range of in vivo Alzheimer's disease-related neurodegenerative markers and cognition, and their interplay, at age 70. Participants from the 1946 British birth cohort study prospectively reported leisure time physical activity five times between ages 36 and 69 and were dichotomized into (i) not active (no participation/month) and (ii) active (participated once or more/month) and further derived into: (0) never active (not active); (1) active before 50's only (≤43 years); (2) active from 50's onwards only (≥53 years); (3) always active (active throughout). Participants underwent 18F-florbetapir Aβ and magnetic resonance imaging at age 70. Regression analyses were conducted to assess the direct and the moderating relationship between leisure time physical activity metrics, Alzheimer's disease-related neurodegeneration markers (including Aβ status, hippocampal and whole-brain volume, and cortical thickness in Alzheimer's disease signature regions) and cognition. All models were adjusted for childhood cognition, education and childhood socioeconomic position, and examined by sex. Findings drawn from 468 participants (49% female) demonstrated a direct association between being active before 50 years old (≤43 years) and throughout life (up to age 69 years), with larger hippocampal volume at age 70 (P < 0.05). There was little evidence that leisure time physical activity had direct effects on other brain health measures (all P > 0.05). However, leisure time physical activity patterns modified and attenuated the association between poorer cognitive functioning at age 70 and a range of Alzheimer's disease-related neurodegenerative markers (Aβ status; hippocampal and whole-brain volume; cortical thickness in Alzheimer's disease regions) (all P < 0.05). We found suggestive evidence that women with early markers of Alzheimer's disease-related neurodegeneration were most sensitive to leisure time physical activity patterns: a lifetime of inactivity in women exacerbated the manifestation of early Alzheimer's disease markers (Aβ and cortical thickness-related cognition), yet, if women were active across life or early in life, it mostly buffered these negative relationships. Engagement in leisure time physical activity in the life course is associated with better cognitive functioning at age 70, even in those with early markers of Alzheimer's disease. If causal, this is likely via multiple pathways, potentially through the preservation of hippocampal volume, as well as via cognitive resilience pathways delaying cognitive manifestations of early markers of Alzheimer's disease, particularly in women. Our findings warrant further research to shed light on the mechanisms of physical activity as a potential disease-modifying intervention of brain health and cognitive resilience.

Alzheimer's disease plasma biomarkers and physical functioning in a diverse sample of adults

INTRODUCTION

The relationship between Alzheimer's disease (AD) plasma biomarkers, and physical functioning (PF) across diverse races and ethnicities remains unclear. This study aims to explore this association in an ethno-racially diverse sample of cognitively unimpaired community-dwelling adults.

METHODS

Data clinical examinations, neuropsychological tests, blood draws, and PF exams (Timed Up and Go [TUG] and Short Physical Performance Battery [SPPB]) were analyzed. Multivariable linear regressions assessed the association between PF and AD plasma biomarkers (amyloid beta [Aβ]40, Aβ42, total tau [t-tau], neurofiliament light chain [NfL]).

RESULTS

The sample (n = 2358; mean age 64.7 years; 65.9% female), was 20% African American, 41.9% non-Hispanic White, and 38.1% Hispanic. Findings indicate that worse PF is linked to higher biomarker levels (p < 0.05). Associations differed by race and ethnicity group. TUG time was associated (p < 0.05) with Aβ40, Aβ42, and tau among non-Hispanic Whites, whereas SPPB scores were associated (p < 0.05) with t-tau and NfL among African Americans.

DISCUSSION

PF, ethnic/racial, and plasma AD biomarker data should be used to aid in developing risk profiles for neurodegenerative diseases.

HIGHLIGHTS

Alzheimer's disease (AD) biomarkers are associated with physical functioning (PF) Ethno-racial variation exists in AD biomarker and PF associations Race and ethnicity should considered when assessing neurodegenerative disease risk.

Molecular and Cellular Foundations of Aging of the Brain: Anti-aging Strategies in Alzheimer's Disease

Alzheimer's disease (AD) is a condition characterized by the gradual degeneration of the nervous system that poses significant challenges to cognitive function and overall mental health. Given the increasing global life expectancy, there is an urgent need for effective strategies to prevent and manage Alzheimer's disease, with a particular focus on anti-aging interventions. Recent scientific advancements have unveiled several promising strategies for combating Alzheimer's disease (AD), ranging from lifestyle interventions to cutting-edge pharmacological treatments and therapies targeting the underlying biological processes of aging and AD. Regular physical exercise, cognitive engagement, a balanced diet, and social interaction serve as key pillars in maintaining brain health. At the same time, therapies target key pathological mechanisms of AD, such as amyloid-beta accumulation, tau abnormalities, neuroinflammation, mitochondrial dysfunction, and synaptic loss, offering potential breakthroughs in treatment. Moreover, cutting-edge innovations such as gene therapy, stem cell transplantation, and novel drug delivery systems are emerging as potential game-changers in the fight against AD. This review critically evaluates the latest research on anti-aging interventions and their potential in preventing and treating Alzheimer's disease (AD) by exploring the connections between aging mechanisms and AD pathogenesis. It provides a comprehensive analysis of both well-established and emerging strategies, while also identifying key gaps in current knowledge to guide future research efforts.

Relationship between physical activity and biomarkers of pathology and neuroinflammation in preclinical autosomal-dominant Alzheimer's disease

Objective

Physical activity (PA) has been linked to reduced Alzheimer's disease (AD) risk. However, less is known about its effects in the AD preclinical stage. We aimed to investigate whether greater PA was associated with lower plasma biomarkers of AD pathology, neural injury, reactive astrocytes, and better cognition in individuals with autosomal-dominant AD due to the presenilin-1 E280A mutation who are virtually guaranteed to develop dementia.

Methods

Twenty-eight cognitively unimpaired mutation carriers (ages x̄ = 29.28) wore a FitBit Charge-4 for 14 days. We calculated their average steps to measure locomotion, and Training Impulse (TRIMP) to quantify the intensity and duration of PAs using heart rate. Plasma amyloid beta 42/40 ratio, phosphorylated tau 181, neurofilament light chain, and glial fibrillary acidic protein (GFAP) were measured. Cognition was assessed with the Consortium to Establish a Registry for Alzheimer's Disease word list learning and delayed recall, Trail Making Test Part A, and Wechsler Adult Intelligence Scale-version IV Digit Span Backward. We conducted multiple linear regressions controlling for age, sex, body mass index, and education.

Results

There were no associations among steps or TRIMP with plasma biomarkers or cognition. Greater TRIMP was related to higher GFAP levels.

Conclusions

PA was not associated with cognition or plasma biomarkers. However, greater intensity and duration of PAs were related to higher GFAP. Participants engaged very little in moderate to vigorous PA. Therefore, light PA may not exert a significant protective effect in preclinical AD. Future work with larger samples and longitudinal data is needed to elucidate further the potential impact of PA on AD progression in the preclinical stages.

Highlights

Locomotion (average steps) was not associated with plasma biomarkers or cognition.Greater training load (training impulse) was related to higher glial fibrillary acidic protein levels in mutation carriers.Light physical activity may not suffice to exert a protective effect on Alzheimer's disease.

The Crosstalk Between Amyloid-β, Retina, and Sleep for the Early Diagnosis of Alzheimer's Disease: A Narrative Review

Alzheimer's disease (AD) is the most common type of dementia, which is characterised by progressive memory loss and accumulation of hallmark markers amyloid-β (Aβ) and neurofibrillary tangles in the diseased brain. The current gold standard diagnostic methods have limitations of being invasive, costly, and not easily accessible. Thus, there is a need for new avenues, such as imaging the retina for early AD diagnosis. Sleep disruption is symptomatically frequent across preclinical and AD subjects. As circadian activity, such as the sleep-wake cycle, is linked to the retina, analysis of their association may be useful additions for achieving predictive AD diagnosis. In this narrative review, we provide an overview of human retina studies concerning the deposition of Aβ, the role of the retina in sleep-wake cycle, the disruption of sleep in AD, and to gather evidence for the associations between Aβ, the retina, and sleep. Understanding the mechanisms behind the associations between Aβ, retina, and sleep could assist in the interpretation of retinal changes accurately in AD.

How Do Modifiable Risk Factors Affect Alzheimer's Disease Pathology or Mitigate Its Effect on Clinical Symptom Expression?

Epidemiological studies show that modifiable risk factors account for approximately 40% of the population variability in risk of developing dementia, including sporadic Alzheimer's disease (AD). Recent findings suggest that these factors may also modify disease trajectories of people with autosomal-dominant AD. With positron emission tomography imaging, it is now possible to study the disease many years before its clinical onset. Such studies can provide key knowledge regarding pathways for either the prevention of pathology or the postponement of its clinical expression. The former "resistance pathway" suggests that modifiable risk factors could affect amyloid and tau burden decades before the appearance of cognitive impairment. Alternatively, the resilience pathway suggests that modifiable risk factors may mitigate the symptomatic expression of AD pathology on cognition. These pathways are not mutually exclusive and may appear at different disease stages. Here, in a narrative review, we present neuroimaging evidence that supports both pathways in sporadic AD and autosomal-dominant AD. We then propose mechanisms for their protective effect. Among possible mechanisms, we examine neural and vascular mechanisms for the resistance pathway. We also describe brain maintenance and functional compensation as bases for the resilience pathway. Improved mechanistic understanding of both pathways may suggest new interventions.

Sleep and physical activity measures are associated with resting-state network segregation in non-demented older adults

Greater physical activity and better sleep are associated with reduced risk of cognitive decline and dementia among older adults, but little is known about their combined associations with measures of brain function and neuropathology. This study investigated potential independent and interactive cross-sectional relationships between actigraphy-estimated total volume of physical activity (TVPA) and sleep patterns [i.e., total sleep time (TST), sleep efficiency (SE)] with resting-state functional magnetic resonance imaging (rs-fMRI) measures of large scale network connectivity and positron emission tomography (PET) measures of amyloid-β. Participants were 135 non-demented older adults from the BIOCARD study (116 cognitively normal and 19 with mild cognitive impairment; mean age = 70.0 years). Using multiple linear regression analyses, we assessed the association between TVPA, TST, and SE with connectivity within the default-mode, salience, and fronto-parietal control networks, and with network modularity, a measure of network segregation. Higher TVPA and SE were independently associated with greater network modularity, although the positive relationship of SE with modularity was only present in amyloid-negative individuals. Additionally, higher TVPA was associated with greater connectivity within the default-mode network, while greater SE was related to greater connectivity within the salience network. In contrast, longer TST was associated with lower network modularity, particularly among amyloid-positive individuals, suggesting a relationship between longer sleep duration and greater network disorganization. Physical activity and sleep measures were not associated with amyloid positivity. These data suggest that greater physical activity levels and more efficient sleep may promote more segregated and potentially resilient functional networks and increase functional connectivity within specific large-scale networks and that the relationship between sleep and functional networks connectivity may depend on amyloid status.

Effects of lifestyle and its interaction with anemia on cognitive function in older adults: A longitudinal study

A better understanding of the impact of lifestyle factors on cognitive function in older adults is critical for developing intervention strategies to achieve successful aging. Moreover, older adults who fulfill the World Health Organization criteria for anemia have a significantly higher risk of developing dementia. In the current study, we aimed to assess the buffering effects of lifestyle on cognitive function in older Chinese adults through a nationally representative survey. The sample consisted of 1201 participants (mean age: 82.39 ± 12.08 years, 52.1% female) from the 2011/2012 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey. Multiple linear regression analyses were used to explore the relationship between changes in lifestyle factors and the rate of cognitive function changes, as well as the effects of the interaction between lifestyle factors and anemia on cognitive function changes. Increased levels of participation in leisure activities, social activities, and dietary diversity delayed cognitive decline. Persistent anemia accelerated cognitive decline, while frequent participation in leisure activities delayed cognitive decline due to anemia. The increased levels of participation in leisure activities, social activities, and dietary diversity can alleviate the cognitive decline caused by aging itself, and more frequently participation in leisure activities can also alleviate the adverse effects of anemia on cognitive function in older adults.

Physical activity and amyloid beta in middle-aged and older adults: A systematic review and meta-analysis

BACKGROUND

One of the pathological hallmarks distinguishing Alzheimer's disease from other dementias is the accumulation of amyloid beta (Aβ). Higher physical activity is associated with decreased dementia risk, and one potential path could be through Aβ levels modulation. We aimed to explore the relationship between physical activity and Aβ in middle-aged and older adults.

METHODS

A systematic search of PubMed, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trials, and SPORTDiscus was performed from inception to April 28, 2022. Studies were eligible if they included physical activity and Aβ data in adults aged 45 years or older. Multi-level meta-analyses of intervention and observational studies were performed to examine the role of physical activity in modulating Aβ levels.

RESULTS

In total, 37 articles were included (8 randomized controlled trials, 3 non-randomized controlled trials, 4 prospective longitudinal studies, and 22 cross-sectional studies). The overall effect size of physical activity interventions on changes in blood Aβ was medium (pooled standardized mean difference = -0.69, 95% confidence interval (95%CI): -1.41 to 0.03; I2 = 74.6%). However, these results were not statistically significant, and there were not enough studies to explore the effects of physical activity on cerebrospinal fluid (CSF) and brain Aβ. Data from observational studies were examined based on measurements of Aβ in the brain using positron emission tomography scans, CSF, and blood. Higher physical activity was positively associated with Aβ only in the CSF (Estimate r = 0.12; 95%CI: 0.05-0.18; I2 = 38.00%).

CONCLUSION

Physical activity might moderately reduce blood Aβ in middle-aged and older adults. However, results were only near statistical significance and might be interpreted with caution given the methodological limitations observed in some of the included studies. In observational studies, higher levels of physical activity were positively associated with Aβ only in CSF. Therefore, further research is needed to understand the modulating role of physical activity in the brain, CSF, and blood Aβ, as well as its implication for cognitive health.

Physical activity and brain amyloid beta: A longitudinal analysis of cognitively unimpaired older adults

INTRODUCTION

The current study evaluated the relationship between habitual physical activity (PA) levels and brain amyloid beta (Aβ) over 15 years in a cohort of cognitively unimpaired older adults.

METHODS

PA and Aβ measures were collected over multiple timepoints from 731 cognitively unimpaired older adults participating in the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Aging. Regression modeling examined cross-sectional and longitudinal relationships between PA and brain Aβ. Moderation analyses examined apolipoprotein E (APOE) ε4 carriage impact on the PA-Aβ relationship.

RESULTS

PA was not associated with brain Aβ at baseline (β = -0.001, p = 0.72) or over time (β = -0.26, p = 0.24). APOE ε4 status did not moderate the PA-Aβ relationship over time (β = 0.12, p = 0.73). Brain Aβ levels did not predict PA trajectory (β = -54.26, p = 0.59).

DISCUSSION

Our study did not identify a relationship between habitual PA and brain Aβ levels.

HIGHLIGHTS

Physical activity levels did not predict brain amyloid beta (Aβ) levels over time in cognitively unimpaired older adults (≥60 years of age). Apolipoprotein E (APOE) ε4 carrier status did not moderate the physical activity-brain Aβ relationship over time. Physical activity trajectories were not impacted by brain Aβ levels.

Cognitive Performance following Single- or Multi-Session Exercise Intervention in Middle Age: A Systematic Review

BACKGROUND

Research in modifiable behaviors, like exercise, on risk for dementia is increasing. Although many studies focus on older adults, brain pathology for Alzheimer's Disease can begin in middle age, suggesting an ideal target for intervention.

METHODS

We conducted a systematic review from exercise intervention studies on cognitive function among healthy, middle-aged participants (45-65). We searched multiple databases (PubMed, PsycINFO, MEDLINE, Cochrane Central Register of Controlled Trials, Google Scholar) for studies using standard, validated, neuropsychological measures following either single- or multi-session interventions in cognitively-unimpaired, middle-aged adults.

RESULTS

We identified 13 eligible studies. There was notable heterogeneity across studies, with varying design, measures, interventions, and results. Results from single-session studies showed improvement in response inhibition, while results for cognitive flexibility were mixed. No significant changes were found on measures of attention, working memory, or processing speed. Results from multi-session studies were more varied. Verbal memory was found to improve while performance on tests of attention and working memory, processing speed, and executive function were mixed.

CONCLUSION

Importantly, for both single-session and multi-session studies, there was no standard set of neuropsychological tests administered, making it more difficult to synthesize the findings into a single narrative. We end with a discussion on future directions and implementation.

Objective sleep was longitudinally associated with brain amyloid burden in mild cognitive impairment

OBJECTIVE

Understanding the longitudinal association of objective sleep and physical activity with brain amyloid burden and cortical glucose metabolism has critical clinical and public health implications for dementia prevention in later life.

METHODS

We enrolled 118 individuals aged ≥65 years with mild cognitive impairment, who were followed up on from August 2015 to September 2019. All participants continuously wore an accelerometer sensor for 7 consecutive days every 3 months and received annual 11 C-Pittsburgh compound-B and 18 F-fluorodeoxyglucose positron emission tomography (PET). Sleep and physical activity parameters were assessed using accelerometer sensor data and PET imaging was quantified using a standardized uptake-value ratio. Fifty-seven participants (48.3%) completed a lifestyle factor assessment and PET imaging over the 3-year period. A linear mixed-effects model was applied to examine the longitudinal association of sleep and physical activity parameters with PET imaging over the 3-year period, controlling for potential confounders.

RESULTS

Sleep efficiency was inversely associated with amyloid uptake in the frontal lobe. Although sleep duration was positively associated with global amyloid uptake, particularly in the frontal lobe, their impact was extremely small. However, physical activity parameters were not significantly associated with the 11 C-Pittsburgh compound-B-uptake. Furthermore, sleep and physical activity parameters were not significantly associated with cortical glucose metabolism.

INTERPRETATION

Lower sleep efficiency could be an early symptom of greater brain amyloid burden at the mild cognitive impairment stage. Therefore, the assessment of sleep may be useful for identifying individuals at higher risk for brain amyloid burden. Future longer term observational studies are required to confirm these findings.

Physical activity, biomarkers of brain pathologies and dementia risk: Results from the Memento clinical cohort

INTRODUCTION

This study aims to examine whether physical activity moderates the association between biomarkers of brain pathologies and dementia risk.

METHODS

From the Memento cohort, we analyzed 1044 patients with mild cognitive impairment, aged 60 and older. Self-reported physical activity was assessed using the International Physical Activity Questionnaire. Biomarkers of brain pathologies comprised medial temporal lobe atrophy (MTA), white matter lesions, and plasma amyloid beta (Aβ)42/40 and phosphorylated tau181. Association between physical activity and risk of developing dementia over 5 years of follow-up, and interactions with biomarkers of brain pathologies were tested.

RESULTS

Physical activity moderated the association between MTA and plasma Aβ42/40 level and increased dementia risk. Compared to participants with low physical activity, associations of both MTA and plasma Aβ42/40 on dementia risk were attenuated in participants with high physical activity.

DISCUSSION

Although reverse causality cannot be excluded, this work suggests that physical activity may contribute to cognitive reserve.

HIGHLIGHTS

Physical activity is an interesting modifiable target for dementia prevention. Physical activity may moderate the impact of brain pathology on dementia risk. Medial temporal lobe atrophy and plasma amyloid beta 42/40 ratio were associated with increased dementia risk especially in those with low level of physical activity.

Effects of a laboratory-based aerobic exercise intervention on brain volume and cardiovascular health markers: protocol for a randomised clinical trial

INTRODUCTION

Physical activity (PA) has beneficial effects on brain health and cardiovascular disease (CVD) risk. Yet, we know little about whether PA-induced changes to physiological mediators of CVD risk influence brain health and whether benefits to brain health may also explain PA-induced improvements to CVD risk. This study combines neurobiological and peripheral physiological methods in the context of a randomised clinical trial to better understand the links between exercise, brain health and CVD risk.

METHODS AND ANALYSIS

In this 12-month trial, 130 healthy individuals between the ages of 26 and 58 will be randomly assigned to either: (1) moderate-intensity aerobic PA for 150 min/week or (2) a health information control group. Cardiovascular, neuroimaging and PA measurements will occur for both groups before and after the intervention. Primary outcomes include changes in (1) brain structural areas (ie, hippocampal volume); (2) systolic blood pressure (SBP) responses to functional MRI cognitive stressor tasks and (3) heart rate variability. The main secondary outcomes include changes in (1) brain activity, resting state connectivity, cortical thickness and cortical volume; (2) daily life SBP stress reactivity; (3) negative and positive affect; (4) baroreflex sensitivity; (5) pulse wave velocity; (6) endothelial function and (7) daily life positive and negative affect. Our results are expected to have both mechanistic and public health implications regarding brain-body interactions in the context of cardiovascular health.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the University of Pittsburgh Institutional Review Board (IRB ID: 19020218). This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule.

TRIAL REGISTRATION NUMBER

NCT03841669.

Determinants of physical activity engagement in older adults

In order to increase engagement in physical activity, it is important to determine which factors contribute to physical activity engagement in older adults. The current study examined the relative predictive ability of several potential determinants, in terms of both the concurrent level as well as longitudinal trajectories. Clinically normal adults aged 61-92 completed the Physical Activity Scale for the Elderly (n = 189 for cross-sectional models; n = 214 for longitudinal models). Potential determinants included age, gender, education, physical health, sensory health, mood, cardiovascular health, cognitive status, and biomarkers of Alzheimer disease (AD). We observed a novel finding that both concurrent physical health (p < 0.001) and change in physical health (p < 0.001) were significant predictors above and beyond other determinants. Concurrent mood predicted levels of physical activity (p = 0.035), particularly in females. These findings suggest that poor physical health and low mood might be important to consider as potential barriers to physical activity engagement in older adults.

Effect of exercise engagement and cardiovascular risk on neuronal injury

INTRODUCTION

Neuronal health as a potential underlying mechanism of the beneficial effects of exercise has been understudied in humans. Furthermore, there has been limited consideration of potential moderators (e.g., cardiovascular health) on the effects of exercise.

METHODS

Clinically normal middle-aged and older adults completed a validated questionnaire about exercise engagement over a 10-year period (n = 75; age 63 ± 8 years). A composite estimate of neuronal injury was formulated that included cerebrospinal fluid-based measures of visinin-like protein-1, neurogranin, synaptosomal-associated protein 25, and neurofilament light chain. Cardiovascular risk was estimated using the Framingham Risk Score.

RESULTS

Cross-sectional analyses showed that greater exercise engagement was associated with less neuronal injury in the group with lower cardiovascular risk (p = 0.008), but not the group with higher cardiovascular risk (p = 0.209).

DISCUSSION

Cardiovascular risk is an important moderator to consider when examining the effects of exercise on cognitive and neural health, and may be relevant to personalized exercise recommendations.

HIGHLIGHTS

We examined the association between exercise engagement and neuronal injury. Vascular risk moderated the association between exercise and neuronal injury. Cardiovascular risk may be relevant to personalized exercise recommendations.

Cognitive reserve and emotion recognition in the context of normal aging

The Cognitive Reserve (CR) hypothesis accounts for individual differences in vulnerability to age- or pathological-related brain changes. It suggests lifetime influences (e.g., education) increase the effectiveness of cognitive processing in later life. While evidence suggests CR proxies predict cognitive performance in older age, it is less clear whether CR proxies attenuate age-related decline on social cognitive tasks. This study investigated the effect of CR proxies on unimodal and cross-modal emotion identification. Sixty-six older adults aged 60-78 years were assessed on CR proxies (Cognitive Reserve Index Questionnaire, NART), unimodal(faces only, voices only), and cross-modal (faces and voices combined) emotion recognition and executive function (Stroop Test). No CR proxy predicted performance on emotion recognition. However, NART IQ predicted performance on the Stroop test; higher NART IQ was associated with better performance. The current study suggests CR proxies do not predict performance on social cognition tests but do predict performance on cognitive tasks.

Combined Ursolic Acid and Resistance/Endurance Training Improve Type 3 Diabetes Biomarkers-Related Memory Deficits in Hippocampus of Aged Male Wistar Rats

Background

Both aging and diabetes are two well-established risk factors related to type 3 diabetes and memory deficits. Accordingly, diabetes multiplies the effects of aging on cognition impairments once these conditions occur simultaneously.

Methods

In this present experimental study, 56 male Wistar rats with HFD/STZ-induced T2D were randomized into seven groups (n = eight animals per group): (1) sedentary old non-diabetic (C); (2) sedentary HFD/STZ-induced T2D (D); (3) sedentary HFD/STZ-induced T2D plus UA (UA) (DU); (4) endurance-trained HFD/STZ-induced T2D (DE); (5) resistance-trained HFD/STZ-induced T2D (DR); (6) endurance-trained HFD/STZ-induced T2D plus UA (DEU); and (7) resistance-trained STZ-diabetic plus UA (DRU) rats. Two-way ANOVA was applied to measure the training, supplementation, and interaction effect on serum and gene expression outcomes.

Result

The study results established no significant interaction effect between the UA supplementation and the resistance/endurance training with regard to the levels of glucose (P = 0.534), insulin (P = 0.327), brain-derived neurotrophic factor (P = 0.191), and insulin-like growth factor-1 (P = 0.448).

Conclusions

To develop novel practical nutritional strategies involving UA intake, further studies are thus needed to clarify how chronic consumption of UA with/without resistance/endurance training reverses cognition disorder process in old male Wistar rats with HFD/STZ-induced T2D.

NREM sleep as a novel protective cognitive reserve factor in the face of Alzheimer's disease pathology

BACKGROUND

Alzheimer's disease (AD) pathology impairs cognitive function. Yet some individuals with high amounts of AD pathology suffer marked memory impairment, while others with the same degree of pathology burden show little impairment. Why is this? One proposed explanation is cognitive reserve i.e., factors that confer resilience against, or compensation for the effects of AD pathology. Deep NREM slow wave sleep (SWS) is recognized to enhance functions of learning and memory in healthy older adults. However, that the quality of NREM SWS (NREM slow wave activity, SWA) represents a novel cognitive reserve factor in older adults with AD pathology, thereby providing compensation against memory dysfunction otherwise caused by high AD pathology burden, remains unknown.

METHODS

Here, we tested this hypothesis in cognitively normal older adults (N = 62) by combining 11C-PiB (Pittsburgh compound B) positron emission tomography (PET) scanning for the quantification of β-amyloid (Aβ) with sleep electroencephalography (EEG) recordings to quantify NREM SWA and a hippocampal-dependent face-name learning task.

RESULTS

We demonstrated that NREM SWA significantly moderates the effect of Aβ status on memory function. Specifically, NREM SWA selectively supported superior memory function in individuals suffering high Aβ burden, i.e., those most in need of cognitive reserve (B = 2.694, p = 0.019). In contrast, those without significant Aβ pathological burden, and thus without the same  need for cognitive reserve, did not similarly benefit from the presence of NREM SWA (B = -0.115, p = 0.876). This interaction between NREM SWA and Aβ status predicting memory function was significant after correcting for age, sex, Body Mass Index, gray matter atrophy, and previously identified cognitive reserve factors, such as education and physical activity (p = 0.042).

CONCLUSIONS

These findings indicate that NREM SWA is a novel cognitive reserve factor providing resilience against the memory impairment otherwise caused by high AD pathology burden. Furthermore, this cognitive reserve function of NREM SWA remained significant when accounting both for covariates, and factors previously linked to resilience, suggesting that sleep might be an independent cognitive reserve resource. Beyond such mechanistic insights are potential therapeutic implications. Unlike many other cognitive reserve factors (e.g., years of education, prior job complexity), sleep is a modifiable factor. As such, it represents an intervention possibility that may aid the preservation of cognitive function in the face of AD pathology, both present moment and longitudinally.

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD.

The Impact of Sustained Ownership of a Pet on Cognitive Health: A Population-Based Study

Objectives: To examine associations between sustained ownership of a pet and cognitive outcomes among a national sample of U.S. adults. Methods: Weighted linear mixed models were estimated using the Health and Retirement Study (2010-2016, n = 1369) to compare repeated measures of cognitive function between respondents who endorsed owning a pet in a sustained manner (>5 years), versus those who owned a pet ≤5 years, and non-pet owners. Results: Respondents aged 65+ who owned a pet >5 years demonstrated higher composite cognitive scores, compared to non-pet owners (β = .76, p = .03). Sustained pet ownership was associated with higher immediate (β = .3, p = .02) and delayed (β = .4, p = .007) word recall scores. There were no significant differences in cognitive scores between pet owners and non-owners aged < 65. Discussion: Sustained ownership of a pet could mitigate cognitive disparities in older adults. Further studies are needed to examine potential causal pathways, including physical activity and stress buffering, versus selection effects.

Activity patterns are associated with fractional lifespan, memory, and gait speed in aged dogs

Maintaining an active lifestyle is considered a hallmark of successful aging. Physical activity significantly reduces the risk of cognitive decline and Alzheimer's disease in humans. However, pain and lack of motivation are important barriers to exercise. Dogs are a remarkable model for translational studies in aging and cognition as they are prone to Canine Cognitive Dysfunction syndrome, which has many similarities with Alzheimer's disease. According to owner reports, changes in activity levels are characteristic of this syndrome, with decreased daytime activity, but also excessive pacing, especially at sleep time. We used physical activity monitors to record the activity of 27 senior dogs and evaluated the association between activity level and age, fractional lifespan, cognitive status measured by an owner questionnaire and cognitive tests. We also assessed the relationship between activity and joint/spinal pain, and the off/on leash gait speed ratio (a potential marker of gait speed reserve and motivation). We found that activity patterns in dogs are associated with fractional lifespan and working memory. Additionally, dogs with higher on/off leash gait speed are more active in the afternoon of weekdays. These results encourage future studies evaluating how physical activity can improve or delay cognitive impairment in senior dogs.

Rationale for a Multi-Factorial Approach for the Reversal of Cognitive Decline in Alzheimer's Disease and MCI: A Review

Alzheimer's disease (AD) is a multifactorial, progressive, neurodegenerative disease typically characterized by memory loss, personality changes, and a decline in overall cognitive function. Usually manifesting in individuals over the age of 60, this is the most prevalent type of dementia and remains the fifth leading cause of death among Americans aged 65 and older. While the development of effective treatment and prevention for AD is a major healthcare goal, unfortunately, therapeutic approaches to date have yet to find a treatment plan that produces long-term cognitive improvement. Drugs that may be able to slow down the progression rate of AD are being introduced to the market; however, there has been no previous solution for preventing or reversing the disease-associated cognitive decline. Recent studies have identified several factors that contribute to the progression and severity of the disease: diet, lifestyle, stress, sleep, nutrient deficiencies, mental health, socialization, and toxins. Thus, increasing evidence supports dietary and other lifestyle changes as potentially effective ways to prevent, slow, or reverse AD progression. Studies also have demonstrated that a personalized, multi-therapeutic approach is needed to improve metabolic abnormalities and AD-associated cognitive decline. These studies suggest the effects of abnormalities, such as insulin resistance, chronic inflammation, hypovitaminosis D, hormonal deficiencies, and hyperhomocysteinemia, in the AD process. Therefore a personalized, multi-therapeutic program based on an individual's genetics and biochemistry may be preferable over a single-drug/mono-therapeutic approach. This article reviews these multi-therapeutic strategies that identify and attenuate all the risk factors specific to each affected individual. This article systematically reviews studies that have incorporated multiple strategies that target numerous factors simultaneously to reverse or treat cognitive decline. We included high-quality clinical trials and observational studies that focused on the cognitive effects of programs comprising lifestyle, physical, and mental activity, as well as nutritional aspects. Articles from PubMed Central, Scopus, and Google Scholar databases were collected, and abstracts were reviewed for relevance to the subject matter. Epidemiological, pathological, toxicological, genetic, and biochemical studies have all concluded that AD represents a complex network insufficiency. The research studies explored in this manuscript confirm the need for a multifactorial approach to target the various risk factors of AD. A single-drug approach may delay the progression of memory loss but, to date, has not prevented or reversed it. Diet, physical activity, sleep, stress, and environment all contribute to the progression of the disease, and, therefore, a multi-factorial optimization of network support and function offers a rational therapeutic strategy. Thus, a multi-therapeutic program that simultaneously targets multiple factors underlying the AD network may be more effective than a mono-therapeutic approach.

Cardiorespiratory Fitness Attenuates the Deleterious Effects of Sleep Apnea on Cerebral Structure and Perfusion in the Wisconsin Sleep Cohort Study

BACKGROUND

Emerging evidence suggests that age-related changes in cerebral health may be sensitive to vascular risk modifiers, such as physical activity and sleep.

OBJECTIVE

We examine whether cardiorespiratory fitness modifies the association of obstructive sleep apnea (OSA) severity with MRI-assessed measures of cerebral structure and perfusion.

METHODS

Using data from a cross-sectional sample of participants (n = 129, 51% female, age range 49.6-85.3 years) in the Wisconsin Sleep Cohort study, we estimated linear models of MRI-assessed total and regional gray matter (GM) and white matter (WM) volumes, WM hyperintensity (WMH:ICV ratio), total lesion volume, and arterial spin labeling (ASL) cerebral blood flow (CBF), using an estimated measure of cardiorespiratory fitness (CRF) and OSA severity as predictors. Participants' sleep was assessed using overnight in-laboratory polysomnography, and OSA severity was measured using the apnea-hypopnea index (AHI), or the mean number of recorded apnea and hypopnea events per hour of sleep. The mean±SD time difference between PSG data collection and MRI data collection was 1.7±1.5 years (range: [0, 4.9 years]).

RESULTS

OSA severity was associated with reduced total GM volume (β=-0.064; SE = 0.023; p = 0.007), greater total WM lesion volume (interaction p = 0.023), and greater WMHs (interaction p = 0.017) in less-fit subjects. Perfusion models revealed significant differences in the association of AHI and regional CBF between fitness groups (interaction ps < 0.05).

CONCLUSION

This work provides new evidence for the protective role of cardiorespiratory fitness against the deleterious effects of OSA on brain aging in late-middle age to older adults.

Association of Physical Activity With Neurofilament Light Chain Trajectories in Autosomal Dominant Frontotemporal Lobar Degeneration Variant Carriers

Importance

Physical activity is associated with cognitive health, even in autosomal dominant forms of dementia. Higher physical activity is associated with slowed cognitive and functional declines over time in adults carrying autosomal dominant variants for frontotemporal lobar degeneration (FTLD), but whether axonal degeneration is a potential neuroprotective target of physical activity in individuals with FTLD is unknown.

Objective

To examine the association between physical activity and longitudinal neurofilament light chain (NfL) trajectories in individuals with autosomal dominant forms of FTLD.

Design, Setting, and Participants

This cohort study included individuals from the ALLFTD Consortium, which recruited patients from sites in the US and Canada. Symptomatic and asymptomatic adults with pathogenic variants in one of 3 common genes associated with FTLD (GRN, C9orf72, or MAPT) who reported baseline physical activity levels and completed annual blood draws were assessed annually for up to 4 years. Genotype, clinical measures, and blood draws were collected between December 2014 and June 2019; data were analyzed from August 2021 to January 2022. Associations between reported baseline physical activity and longitudinal plasma NfL changes were assessed using generalized linear mixed-effects models adjusting for baseline age, sex, education, functional severity, and motor symptoms.

Exposures

Baseline physical activity levels reported via the Physical Activity Scale for the Elderly. To estimate effect sizes, marginal means were calculated at 3 levels of physical activity: 1 SD above the mean represented high physical activity, 0 SD represented average physical activity, and 1 SD below the mean represented low physical activity.

Main Outcomes and Measures

Annual plasma NfL concentrations were measured with single-molecule array technology.

Results

Of 160 included FTLD variant carriers, 84 (52.5%) were female, and the mean (SD) age was 50.7 (14.7) years. A total of 51 (31.8%) were symptomatic, and 77 carried the C9orf72 variant; 39, GRN variant; and 44, MAPT variant. Higher baseline physical activity was associated with slower NfL trajectories over time. On average, NfL increased 45.8% (95% CI, 22.5 to 73.7) over 4 years in variant carriers. Variant carriers with high physical activity demonstrated 14.0% (95% CI, -22.7 to -4.3) slower NfL increases compared with those with average physical activity and 30% (95% CI, -52.2 to -8.8) slower NfL increases compared with those with low physical activity. Within genotype, C9orf72 and MAPT carriers with high physical activity evidenced 18% to 21% (95% CI, -43.4 to -7.2) attenuation in NfL, while the association between physical activity and NfL trajectory was not statistically significant in GRN carriers. Activities associated with higher cardiorespiratory and cognitive demands (sports, housework, and yardwork) were most strongly correlated with slower NfL trajectories (vs walking and strength training).

Conclusions and Relevance

In this study, higher reported physical activity was associated with slower progression of an axonal degeneration marker in individuals with autosomal dominant FTLD. Physical activity may serve as a primary prevention target in FTLD.

Insulin Homeostasis Mediates the Relationship Between Cardiorespiratory Fitness and Cognitive Speed in Aging Adults

BACKGROUND

Cardiorespiratory fitness (CRF) supports cognition, though it is unclear what mechanisms underly this relationship. Insulin resistance adversely affects cognition but can be reduced with habitual exercise.

OBJECTIVE

We investigated whether insulin resistance statistically mediates the relationship between CRF and cognition.

METHODS

In our observational study, we included n = 1,131 cognitively unimpaired, nondiabetic older adults from a cohort characterized by elevated Alzheimer's disease (AD) risk. We estimated CRF (eCRF) using a validated equation that takes age, sex, body mass index, resting heart rate, and habitual physical activity as inputs. The Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) quantified insulin resistance. Standardized cognitive factor scores for cognitive speed/flexibility, working memory, verbal learning/memory, and immediate memory were calculated from a battery of neuropsychological tests. Linear regression models and bootstrapped estimates of indirect effects were used to determine whether HOMA-IR mediated significant relationships between eCRF and cognition.

RESULTS

eCRF was positively associated with cognitive speed/flexibility (p = 0.034). When controlling for HOMA-IR, eCRF was no longer associated with cognitive speed/flexibility (p = 0.383). HOMA-IR had a significant indirect effect on the eCRF-cognition relationship (B = 0.025, CI = [0.003,0.051]). eCRF was not associated with working memory (p = 0.236), immediate memory (p = 0.345), or verbal learning/memory (p = 0.650).

CONCLUSION

Among older adults at risk for AD, peripheral insulin resistance mediates the relationship between CRF and cognitive speed.

Explaining the association between social and lifestyle factors and cognitive functions: a pathway analysis in the Memento cohort

Background

This work aimed to investigate the potential pathways involved in the association between social and lifestyle factors, biomarkers of Alzheimer’s disease and related dementia (ADRD), and cognition.

Methods

The authors studied 2323 participants from the Memento study, a French nationwide clinical cohort. Social and lifestyle factors were education level, current household incomes, physical activity, leisure activities, and social network from which two continuous latent variables were computed: an early to midlife (EML) and a latelife (LL) indicator. Brain magnetic resonance imaging (MRI), lumbar puncture, and amyloid-positron emission tomography (PET) were used to define three latent variables: neurodegeneration, small vessel disease (SVD), and AD pathology. Cognitive function was defined as the underlying factor of a latent variable with four cognitive tests. Structural equation models were used to evaluate cross-sectional pathways between social and lifestyle factors and cognition.

Results

Participants’ mean age was 70.9 years old, 62% were women, 28% were apolipoprotein-ε4 carriers, and 59% had a Clinical Dementia Rating (CDR) score of 0.5. Higher early to midlife social indicator was only directly associated with better cognitive function (direct β = 0.364 (0.322; 0.405), with no indirect pathway through ADRD biomarkers (total β = 0.392 (0.351; 0.429)). In addition to a direct effect on cognition (direct β = 0.076 (0.033; 0.118)), the association between latelife lifestyle indicator and cognition was also mostly mediated by an indirect effect through lower neurodegeneration (indirect β = 0.066 (0.042; 0.090) and direct β =  − 0.116 (− 0.153; − 0.079)), but not through AD pathology nor SVD.

Conclusions

Early to midlife social factors are directly associated with higher cognitive functions. Latelife lifestyle factors may help preserve cognitive functions through lower neurodegeneration.

Relationship between Physical Activity and Emotional Regulation Strategies in Early Adulthood: Mediating Effects of Cortical Thickness

We investigated the relationship between physical activity (PA) and emotional regulation strategies among college students to establish the mediating role of cortical thickness. A total of 60 university students (18−20 years old) were enrolled in this study. The International Physical Activity Questionnaire (IPAQ-L) was used to estimate PA levels. Based on the International Physical Activity Working Group standards, PA levels were divided into low, medium, and high PA groups; emotional regulation strategies were determined by the Emotion Regulation Questionnaire (ERQ), including the Cognitive Reappraisal Scale (CR) and the Expressive Suppression Scale (ES). Structural magnetic resonance imaging (MRI) was used to measure cortical thickness. Differences in use of the ES strategy among high, medium, and low PA groups were not marked. However, compared to the low PA group, the CR strategy was frequently used in the high PA group, with a thicker right hemisphere rostral anterior cingulate cortex (rrACC). PA levels were positively correlated with thickness of the rrACC cortex (r = 0.398, p = 0.002 < 0.05) and CR strategy (r = 0.398, p = 0.002 < 0.05), and negatively correlated with the ES strategy (r = −0.348, p = 0.007 < 0.05). The rrACC cortical thickness played a partial mediating role in the relationship between PA and CR strategy, accounting for 33.1% of total effect values. These findings indicate that although the negative correlation between PA and ES was not significant, the positive correlation between PA with CR was significant, and rrACC thickness played a partial mediating role in the relationship between PA and CR, providing new evidence toward comprehensively revealing the relationship between PA, rrACC cortical thickness, and emotion regulation strategies.

Cardiorespiratory fitness and cognition in persons at risk for Alzheimer's disease

Introduction

This study examined the relationship between cardiorespiratory fitness (CRF) and longitudinal cognitive functioning in a cohort enriched with risk factors for Alzheimer's disease (AD).

Methods

A total of 155 enrollees in the Wisconsin Registry for Alzheimer's Prevention completed repeat comprehensive neuropsychological evaluations that assessed six cognitive domains. Peak oxygen consumption (VO2peak) was the primary measure of CRF. Random effects regression was used to investigate the effect of CRF on cognitive trajectories.

Results

Higher CRF was associated with slower decline in the cognitive domains of verbal learning and memory (P < .01) and visual learning and memory (P < .042). Secondary analyses indicated that these effects were stronger among men than women, and for noncarriers of the apolipoprotein E ε4 allele.

Discussion

Higher CRF was associated with a slower rate of the decline in episodic memory that occurs as a natural consequence of aging in a cohort enriched with risk factors for AD.

Area Deprivation Index as a Surrogate of Resilience in Aging and Dementia

Area deprivation index (ADI), a tool used to capture the multidimensional neighborhood socioeconomic disadvantage across populations, is highly relevant to the field of aging and Alzheimer’s disease and Alzheimer’s disease related dementias (AD/ADRD). ADI is specifically relevant in the context of resilience, a broad term used to explain why some older adults have better cognitive outcomes than others. The goal of this mini-review is three-fold: (1) to summarize the current literature on ADI and its link to cognitive impairment outcomes; (2) suggest possible mechanisms through which ADI may have an impact on AD/ADRD outcomes, and (3) discuss important considerations when studying relations between ADI and cognitive as well as brain health. Though difficult to separate both the upstream factors that emerge from high (worse) ADI and all the mechanisms at play, ADI is an attractive proxy of resilience that captures multifactorial contributors to the risk of dementia. In addition, a life-course approach to studying ADI may allow us to capture resilience, which is a process developed over the lifespan. It might be easier to build, preserve or improve resilience in an environment that facilitates instead of hindering physical, social, and cognitively beneficial activities. Neighborhood disadvantage can adversely impact cognitive impairment risk but be at the same time a modifiable risk factor, amenable to policy changes that can affect communities.

Non-Modifiable Factors as Moderators of the Relationship Between Physical Activity and Brain Volume: A Cross-Sectional UK Biobank Study

BACKGROUND

Previous research suggests physical activity attenuates grey and white matter loss; however, there appears to be individual variability in this effect. Understanding factors that can influence the relationship between physical activity and brain volume may enable prediction of individual response.

OBJECTIVE

The current study examined the relationship between objectively-measured physical activity and brain volume; and whether this relationship is moderated by age, sex, or a priori candidate genetic factors, brain-derived neurotrophic factor (BDNF) Val66Met, or apolipoprotein (APOE) ɛ4 allele carriage.

METHODS

Data from 10,083 men and women (50 years and over) of the UK Biobank were used to examine the study objectives. All participants underwent a magnetic resonance imaging scan to quantify grey and white matter volumes, physical activity monitoring via actigraphy, and genotyping.

RESULTS

Physical activity was associated with total grey matter volume, total white matter volume, and right hippocampal volume. Only males had an association between higher physical activity levels and greater cortical grey matter volume, total grey matter volume, and right hippocampal volume. Age moderated the relationship between physical activity and white matter volume.

CONCLUSION

Our results indicate that in males, but not females, an association exists between objectively-measured physical activity and grey matter volume. Age may also play a role in impacting the relationship between physical activity and brain volume. Future research should evaluate longitudinal brain volumetrics to better understand the nature of age and sex-effects on the physical activity and brain volume relationship.

Role of Cardiovascular Risk Factors on the Association Between Physical Activity and Brain Integrity Markers in Older Adults

BACKGROUND AND OBJECTIVES

Physical activity has been associated with a decreased risk for dementia, but the mechanisms underlying this association remain to be determined. Our objective was to assess whether cardiovascular risk factors mediate the association between physical activity and brain integrity markers in older adults.

METHODS

At baseline, participants from the Age-Well study completed a physical activity questionnaire and underwent cardiovascular risk factors collection (systolic blood pressure, body mass index [BMI], current smoker status, and high-density lipoprotein cholesterol, total cholesterol, and insulin levels) and multimodal neuroimaging (structural MRI, diffusion MRI, FDG-PET, and florbetapir PET). Multiple regressions were conducted to assess the association among physical activity, cardiovascular risk factors, and neuroimaging. Mediation analyses were performed to test whether cardiovascular risk factors mediated the associations between physical activity and neuroimaging.

RESULTS

A total of 134 cognitively unimpaired older adults (≥65 years) were included. Higher physical activity was associated with higher gray matter (GM) volume (β = 0.174, p = 0.030) and cerebral glucose metabolism (β = 0.247, p = 0.019) but not with amyloid deposition or white matter integrity. Higher physical activity was associated with lower insulin level and BMI but not with the other cardiovascular risk factors. Lower insulin level and BMI were related to higher GM volume but not to cerebral glucose metabolism. When controlling for insulin level and BMI, the association between physical activity and cerebral glucose metabolism remained unchanged, while the association with GM volume was lost. When insulin level and BMI were entered in the same model, only BMI remained a significant predictor of GM volume. Mediation analyses confirmed that insulin level and BMI mediated the association between physical activity and GM volume. Analyses were replicated within Alzheimer disease-sensitive regions and results remained overall similar.

DISCUSSION

The association between physical activity and GM volume is mediated by changes in insulin level and BMI. In contrast, the association with cerebral glucose metabolism seems to be independent from cardiovascular risk factors. Older adults engaging in physical activity experience cardiovascular benefits through the maintenance of a lower BMI and insulin level, resulting in greater structural brain integrity. This study has implications for understanding how physical activity affects brain health and may help in developing strategies to prevent or delay age-related decline.

TRIAL REGISTRATION INFORMATION

EudraCT: 2016-002,441-36; IDRCB: 2016-A01767-44; ClinicalTrials.gov Identifier: NCT02977819.

Men and women show partly distinct effects of physical activity on brain integrity

Introduction

Physical inactivity and female sex are independently associated with increased Alzheimer's disease (AD) lifetime risk. This study investigates the possible interactions between sex and physical activity on neuroimaging biomarkers.

Methods

In 134 cognitively unimpaired older adults (≥65 years, 82 women) from the Age-Well randomized controlled trial (baseline data), we investigated the association between physical activity and multimodal neuroimaging (gray matter volume, glucose metabolism, perfusion, and amyloid burden), and how sex modulates these associations.

Results

The anterior cingulate cortex volume was independently associated with sex and physical activity. Sex and physical activity interacted on perfusion and amyloid deposition in medial parietal regions, such that physical activity was related to perfusion only in women, and to amyloid burden only in men.

Discussion

Physical activity has both sex-dependent and sex-independent associations with brain integrity. Our findings highlight partly distinct reserve mechanisms in men and women, which might in turn influence their risk of AD.

Highlights

Sex and physical activity have been linked to Alzheimer's disease (AD) progression.The association of sex and physical activity with brain health is partly independent.Different reserve mechanisms exist in men and women.

The Association Between Alzheimer's Disease-Related Markers and Physical Activity in Cognitively Normal Older Adults

Previous studies have indicated that physical activity may be beneficial in reducing the risk for Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. The goal of this study was to evaluate the relationship between habitual physical activity levels and brain amyloid deposition and AD-related blood biomarkers (i.e., measured using a novel high-performance mass spectrometry-based assay), in apolipoprotein E (APOE) ε4 carriers and noncarriers. We evaluated 143 cognitively normal older adults, all of whom had brain amyloid deposition assessed using positron emission tomography and had their physical activity levels measured using the International Physical Activity Questionnaire (IPAQ). We observed an inverse correlation between brain amyloidosis and plasma beta-amyloid (Aβ)₁₋₄₂ but found no association between brain amyloid and plasma Aβ₁₋₄₀ and amyloid precursor protein (APP)_669−711. Additionally, higher levels of physical activity were associated with lower plasma Aβ₁₋₄₀, Aβ₁₋₄₂, and APP_669−711 levels in APOE ε4 noncarriers. The ratios of Aβ₁₋₄₀/Aβ₁₋₄₂ and APP_669−711/Aβ₁₋₄₂, which have been associated with higher brain amyloidosis in previous studies, differed between APOE ε4 carriers and non-carriers. Taken together, these data indicate a complex relationship between physical activity and brain amyloid deposition and potential blood-based AD biomarkers in cognitively normal older adults. In addition, the role of APOE ε4 is still unclear, and more studies are necessary to bring further clarification.

Examination of Neurofilament Light Chain Serum Concentrations, Physical Activity, and Cognitive Decline in Older Adults

IMPORTANCE

Little is known about the association of serum neurofilament light chain (NfL) concentrations and physical activity with the rate of cognitive decline in older adults.

OBJECTIVE

To examine the association of physical activity and NfL concentrations with cognitive decline in older adults over time.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Chicago Health and Aging Project (CHAP), a population-based cohort study that recruited participants through door-to-door census in 4 Chicago-area communities and collected data between 1993 and 2012 in cycles of 3 years. Participants in CHAP who had 2 or more cognitive function assessments and at least 1 blood sample collected for NfL measurement were selected for inclusion in the current study. Data were analyzed from January to December 2021.

EXPOSURES

Self-reported physical activity (minutes per week) and serum NfL concentration (pg/mL).

MAIN OUTCOMES AND MEASURES

Associations of baseline physical activity and NfL concentrations with changes in global cognitive function over time as evaluated using the East Boston Memory Test for episodic memory, the Symbol Digit Modalities Test for perceptual speed, and the Mini-Mental State Examination. Mixed-effects regression analyses were conducted to examine associations at baseline and longitudinally.

RESULTS

The study sample included 1158 participants (695 [60%] African American; 728 [63%] female), with a mean (SD) age of 77.4 (6.0) years and a mean educational level of 12.6 (3.5) years. Among participants with high NfL concentrations (>25 pg/mL), those who engaged in medium physical activity (<150 minutes per week) had a 12% slower rate of global cognitive decline (SD units, or β, -0.065; 95% CI, -0.099 to -0.032) and participants who engaged in high physical activity (≥150 minutes per week) had a 36% slower rate of decline (β, -0.048; 95% CI, -0.080 to -0.016) than did participants with low physical activity (no reported participation) (β, -0.075; 95% CI, -0.108 to -0.041). For participants with low NfL concentrations (≤25 pg/mL), those who took part in medium physical activity had 43% slower global cognitive decline (β, -0.025; 95% CI, -0.043 to -0.007) and individuals who participated in high physical activity had 30% slower decline (β, -0.031; 95% CI, -0.048 to -0.014) than did those who participated in low physical activity (β, -0.046; 95% CI, -0.066 to -0.025).

CONCLUSIONS AND RELEVANCE

The findings suggest that physical activity is associated with diminished cognitive decline among older adults with increased serum NfL concentrations. The results support the potential use of blood biomarkers in measuring the benefits of health behaviors, such as physical activity, and early intervention for older adults at risk for cognitive decline.

Can exercise training teach us how to treat Alzheimer's disease?

Alzheimer's disease (AD) is the most common cause of dementia and there is currently no cure. Novel approaches to treat AD and curb the rapidly increasing worldwide prevalence and costs of dementia are needed. Physical inactivity is a significant modifiable risk factor for AD, estimated to contribute to 12.7% of AD cases worldwide. Exercise interventions in humans and animals have shown beneficial effects of exercise on brain plasticity and cognitive functions. In animal studies, exercise also improved AD pathology. The mechanisms underlying these effects of exercise seem to be associated mainly with exercise performance or cardiorespiratory fitness. In addition, exercise-induced molecules of peripheral origin seem to play an important role. Since exercise affects the whole body, there likely is no single therapeutic target that could mimic all the benefits of exercise. However, systemic strategies may be a viable means to convey broad therapeutic effects in AD patients. Here, we review the potential of physical activity and exercise training in AD prevention and treatment, shining light on recently discovered underlying mechanisms and concluding with a view on future development of exercise-free treatment strategies for AD.

Loss of association between plasma irisin levels and cognition in Alzheimer's disease

BACKGROUND

Irisin, an exercise-induced myokine, has been shown to have beneficial effects on cognitive and metabolic functions. However, previous studies assessing the levels of circulating irisin in patients with Alzheimer's disease (AD) or diabetes mellitus (DM) have provided inconsistent results. This suggests that the normal physiological action of irisin may be altered by disease-associated pathological conditions in target organs.

OBJECTIVE

To investigate the association of plasma levels of irisin with cognition and brain structures according to the presence or absence of AD and DM.

METHODS

Plasma levels of irisin, multi-domain cognition, and volumes of relevant brain regions were assessed using enzyme-linked immunoassay, neuropsychological test, and magnetic resonance imaging, respectively. We classified 107 participants by cognitive (cognitively normal [CN, n = 23], mild cognitive impairment [MCI, n = 49], and AD [n = 35]) and metabolic (non-DM [n = 75] and DM [n = 32]) states.

RESULTS

Disease state-stratified multiple regression analyses showed that plasma levels of irisin were positively associated with cognition only in participants without AD (CN plus MCI). By contrast, in participants with AD, these associations lost significance, and furthermore, higher levels of irisin indicated smaller hippocampal, superior temporal, and inferior frontal volumes. The association between plasma irisin levels and cognition was not affected by the presence of DM. Consistently, moderation analysis revealed that the relationship between plasma irisin levels and cognition or brain structures was significantly modified by the presence of AD, not that of DM.

CONCLUSION

Our findings suggest that the beneficial actions of circulating irisin on cognition may be attenuated by AD-induced pathological conditions in the brain.

Apolipoprotein E Genotype Moderation of the Association Between Physical Activity and Brain Health. A Systematic Review and Meta-Analysis

Introduction

Possession of one or two e4 alleles of the apolipoprotein E (APOE) gene is associated with cognitive decline and dementia risk. Some evidence suggests that physical activity may benefit carriers of the e4 allele differently.

Method

We conducted a systematic review and meta-analysis of studies which assessed APOE differences in the association between physical activity and: lipid profile, Alzheimer's disease pathology, brain structure and brain function in healthy adults. Searches were carried out in PubMed, SCOPUS, Web of Science and PsycInfo.

Results

Thirty studies were included from 4,896 papers screened. Carriers of the e4 allele gained the same benefit from physical activity as non-carriers on most outcomes. For brain activation, e4 carriers appeared to gain a greater benefit from physical activity on task-related and resting-state activation and resting-state functional connectivity compared to non-carriers. Post-hoc analysis identified possible compensatory mechanisms allowing e4 carriers to maintain cognitive function.

Discussion

Though there is evidence suggesting physical activity may benefit e4 carriers differently compared to non-carriers, this may vary by the specific brain health outcome, perhaps limited to brain activation. Further research is required to confirm these findings and elucidate the mechanisms.

Cognitive Aging and the Promise of Physical Activity

Is the field of cognitive aging irretrievably concerned with decline and deficits, or is it shifting to emphasize the hope of preservation and enhancement of cognitive function in late life? A fragment of an answer comes from research attempting to understand the reasons for individual variability in the extent and rate of cognitive decline. This body of work has created a sense of optimism based on evidence that there are some health behaviors that amplify cognitive performance or mitigate the rate of age-related cognitive decline. In this context, we discuss the role of physical activity on neurocognitive function in late adulthood and summarize how it can be conceptualized as a constructive approach both for the maintenance of cognitive function and as a therapeutic for enhancing or optimizing cognitive function in late life. In this way, physical activity research can be used to shape perceptions of cognitive aging. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Genetically identical twins show comparable tau PET load and spatial distribution

Tau accumulation starts during the preclinical phase of Alzheimer’s disease and is closely associated with cognitive decline. For preventive purposes, it is important to identify factors associated with tau accumulation and spread. Studying genetically identical twin-pairs may give insight into genetic and environmental contributions to tau pathology, as similarities in identical twin-pairs largely result from genetic factors, while differences in identical twin-pairs can largely be attributed to non-shared, environmental factors. This study aimed to examine similarities and dissimilarities in a cohort of genetically identical older twin-pairs in (i) tau load; and (ii) spatial distribution of tau, measured with ¹⁸F-flortaucipir PET.

We selected 78 genetically identical twins (39 pairs; average age 73 ± 6 years), enriched for amyloid-β pathology and APOE ε4 carriership, who underwent dynamic ¹⁸F-flortaucipir PET. We extracted binding potentials (BP_ND) in entorhinal, temporal, widespread neocortical and global regions, and examined within-pair similarities in BP_ND using age and sex corrected intra-class correlations. Furthermore, we tested whether twin-pairs showed a more similar spatial ¹⁸F-flortaucipir distribution compared to non-twin pairs, and whether the participant’s co-twin could be identified solely based on the spatial ¹⁸F-flortaucipir distribution. Last, we explored whether environmental (e.g. physical activity, obesity) factors could explain observed differences in twins of a pair in ¹⁸F-flortaucipir BP_ND.

On visual inspection, Alzheimer’s disease-like ¹⁸F-flortaucipir PET patterns were observed, and although we mainly identified similarities in twin-pairs, some pairs showed strong dissimilarities. ¹⁸F-flortaucipir BP_ND was correlated in twins in the entorhinal (r = 0.40; P = 0.01), neocortical (r = 0.59; P < 0.01) and global (r = 0.56; P < 0.01) regions, but not in the temporal region (r = 0.20; P = 0.10). The ¹⁸F-flortaucipir distribution pattern was significantly more similar between twins of the same pair [mean r = 0.27; standard deviation (SD) = 0.09] than between non-twin pairings of participants (mean r = 0.01; SD = 0.10) (P < 0.01), also after correcting for proxies of off-target binding. Based on the spatial ¹⁸F-flortaucipir distribution, we could identify with an accuracy of 86% which twins belonged to the same pair. Finally, within-pair differences in ¹⁸F-flortaucipir BP_ND were associated with within-pair differences in depressive symptoms (0.37 < β < 0.56), physical activity (−0.41 < β < −0.42) and social activity (−0.32 < β < −0.36) (all P < 0.05).

Overall, identical twin-pairs were comparable in tau load and spatial distribution, highlighting the important role of genetic factors in the accumulation and spreading of tau pathology. Considering also the presence of dissimilarities in tau pathology in identical twin-pairs, our results additionally support a role for (potentially modifiable) environmental factors in the onset of Alzheimer’s disease pathological processes, which may be of interest for future prevention strategies.

Late-Life Physical Activities Moderate the Relationship of Amyloid-β Pathology with Neurodegeneration in Individuals Without Dementia

BACKGROUND

Physical activities (PA) have been suggested to reduce the risk of Alzheimer's disease (AD) dementia. However, information on the neuropathological links underlying the relationship is limited.

OBJECTIVE

We investigated the role of midlife and late-life PA with in vivo AD neuropathologies in old adults without dementia.

METHODS

This study included participants from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer's disease (KBASE). The participants underwent comprehensive clinical and neuropsychological assessment, [11C] Pittsburgh Compound B positron emission tomography (PET), [18F] fluorodeoxyglucose PET, and magnetic resonance imaging. Using the multi-modal brain imaging data, in vivo AD pathologies including global amyloid deposition, AD-signature region cerebral glucose metabolism (AD-CM), and AD-signature region cortical thickness (AD-CT) were quantified. Both midlife and late-life PA of participants were measured using the Lifetime Total Physical Activity Questionnaire.

RESULTS

This study was performed on 260 participants without dementia (195 with normal cognitive function and 65 with mild cognitive impairment). PA of neither midlife nor late-life showed direct correspondence with any neuroimaging biomarker. However, late-life PA moderated the relationship of brain amyloid-β (Aβ) deposition with AD-CM and AD-CT. Aβ positivity had a significant negative effect on both AD-CM and AD-CT in individuals with lower late-life PA, but those with higher late-life PA did not show such results. Midlife PA did not have such a moderation effect.

CONCLUSION

The findings suggest that physically active lifestyle in late-life, rather than that in midlife, may delay AD-associated cognitive decline by decreasing Aβ-induced neurodegenerative changes in old adults.

Beneficial Effects of a Short Course of Physical Prehabilitation on Neurophysiological Functioning and Neurovascular Biomarkers in Patients Undergoing Coronary Artery Bypass Grafting

This study aimed to evaluate the effects of a short course of physical prehabilitation on neurophysiological functioning and markers of the neurovascular unit in patients undergoing coronary artery bypass grafting (CABG). We performed a prospective randomized study involving 97 male CABG patients aged 45–70 years, 47 of whom underwent a 5–7-day preoperative course of aerobic physical training (PhT). Both groups of patients were comparable with respect to baseline clinical and anamnestic characteristics. An extended neuropsychological and electroencephalographic (EEG) study was performed before surgery and at 7–10 days after CABG. Markers of the neurovascular unit [S100β, neuron-specific enolase (NSE), and brain-derived neurotrophic factor (BDNF)] were examined as metabolic correlations of early postoperative cognitive dysfunction (POCD) at three time points: before surgery, within the first 24 h after surgery, and 7–10 days after CABG. POCD developed in 58% of patients who underwent preoperative PhT, and in 79.5% of patients who did not undergo training, 7–10 days after CABG. Patients without prehabilitation demonstrated a higher percentage of theta1 power increase in the relative change values as compared to the PhT patients (p = 0.015). The short preoperative course of PhT was associated with low plasma S100β concentration, but high BDNF levels in the postoperative period. Patients who underwent a short preoperative course of PhT had better cognitive and electrical cortical activity indicators. Markers of the neurovascular unit indicated lower perioperative brain injury after CABG in those who underwent training. A short course of PhT before CABG can decrease the brain’s susceptibility to ischemia and reduce the severity of cognitive impairments in cardiac surgery patients. Electrical brain activity indicators and neurovascular markers, such as S100β and BDNF, can be informative for the effectiveness of cardiac rehabilitation programs.

Physical activity and cognitive and imaging biomarkers of Alzheimer's disease in down syndrome

Adults with Down syndrome (DS) are at risk for Alzheimer's disease. Despite sharing trisomy 21, however, there is variability in the age of disease onset. This variability may mean that other factors, such as lifestyle, influence cognitive aging and disease timing. The present study assessed the association between everyday life physical activity using an actigraph accelerometer and cognitive functioning and early Alzheimer's disease pathology via positron emission tomography amyloid-β and tau and diffusion tension imaging measures of white matter integrity in 61 non-demented adults with DS. Percent time in sedentary behavior and in moderate-to-vigorous activity were associated (negatively and positively, respectively) with cognitive functioning (r = -.472 to .572, p < 0.05). Neither sedentary behavior nor moderate-to-vigorous activity were associated with amyloid-β or tau, but both were associated with white matter integrity in the superior and inferior longitudinal fasciculus (Fractional Anisotropy: r = -.397 to -.419, p < 0.05; Mean Diffusivity: r = .400, p < 0.05). Longitudinal studies are needed to determine if physical activity promotes healthy aging in DS.