Reduced lean mass in early Alzheimer disease and its association with brain atrophy

Human skeletal muscle mitochondrial pathways are impacted by a neuropathologic diagnosis of Alzheimer's disease

Alzheimer's disease (AD) is associated with reduced lean mass and impaired skeletal muscle mitochondrial and motor function. Although primary mitochondrial defects in AD may underlie these findings, molecular alterations in AD have not been thoroughly examined in human skeletal muscle. Here, we used two human skeletal muscle types, quadriceps (n = 81) and temporalis (n = 66), to compare the proteome of individuals with a neuropathologic AD diagnosis based on AD Neuropathologic Change (ADNPC+: n = 54 temporalis, 44 quadriceps) to controls (ADNPC-: n = 27 temporalis, 22 quadriceps). We determined the effects of ADNPC status within each muscle and within apolipoprotein E4 (APOE4) carriers and APOE4 non-carriers. Pathways that support mitochondrial metabolism, including oxidative phosphorylation, were downregulated in skeletal muscle of ADNPC+ versus ADNPC- individuals. Similar mitochondrial effects were observed across muscle types and APOE4 carrier groups, but nearly four times as many proteins were altered in temporalis versus quadriceps tissue and mitochondrial effects were most pronounced in APOE4 carriers compared to APOE4 non-carriers. Of all detected oxidative phosphorylation proteins, the expression of ∼29-61 % (dependent on muscle/APOE4 carrier group) significantly correlated with AD progression, ranked by Clinical Dementia Rating and ADNPC scores. Of these, 23 proteins decreased in expression with greater AD progression in all skeletal muscle type and APOE4 carrier groups. This is the first study to assess differences in the human skeletal muscle proteome in the context of AD. Our work shows that systemic mitochondrial alterations in AD extend to skeletal muscle and these effects are amplified by APOE4 and correlate with AD progression.

The association of sarcopenia, possible sarcopenia and cognitive impairment: A systematic review and meta-analysis

OBJECTIVES

The study aimed to investigate the relationship between sarcopenia, possible sarcopenia, and cognitive impairment, and to analyze the impact of potential moderating factors.

METHODS

A comprehensive search was conducted on PubMed, EmBase, Web of Science, Cochrane Library, CNKI, Wanfang Databases, VIP and SinoMed from inception until March 2025. The quality of cross-sectional studies was assessed using the Agency for Healthcare Research and Quality Scale, while the Newcastle-Ottawa scale was used to assess the quality of included case-control and cohort studies. Subgroup analyses and meta-regression were employed to explore potential moderating variables and heterogeneity.

RESULTS

A total of 31 studies were included in this systematic review, of which 27 studies were quantitatively analyzed. The meta-analysis revealed that both sarcopenia and possible sarcopenia significantly associated with cognitive impairment (OR=1.88, 95%CI = 1.71-2.08), (OR=1.96, 95%CI = 1.50-2.58). Subgroup analyses revealed a stronger association between sarcopenia and cognitive impairment in specific demographics: among females with sarcopenia (OR=3.22, 95%CI = 1.23-8.40), in Asian populations (OR=1.96, 95%CI = 1.76-2.18), and within hospital settings (OR=3.12, 95%CI = 2.18-4.48). These findings underscore the influence of gender, ethnicity, and healthcare environment on the relationship between sarcopenia and cognitive impairment. An assessment of publication bias within studies providing adjusted odds ratios indicated potential bias. However, sensitivity analyses and trim-and-filling analyses confirmed the robustness of our findings, suggesting that the observed associations remain reliable despite the presence of publication bias.

CONCLUSIONS

Individuals with sarcopenia or possible sarcopenia have approximately twice the odds of developing cognitive impairment compared to those without sarcopenia. Implementing systematic screening and targeted interventions for possible sarcopenia patients is essential to prevent from cognitive decline. Specifically, healthcare professionals should focus on women and inpatients with sarcopenia, employing proactive measures to avert cognitive impairment.

The association of hemopexin, muscle quality, and sarcopenia in Japanese older adults with cognitive impairment: a cross-sectional study

OBJECTIVE

To examine the cross-sectional associations of hemopexin, muscle quality, and sarcopenia status with cognitive function among older Japanese adults with cognitive impairment, and to explore the potential sex-specific differences.

METHODS

A total of 580 older adults (372 women, 208 men; mean age 83.3 ± 6.2 years) who presented with cognitive impairment at the Kyoto Dementia Comprehensive Center between 2018 and 2022 were enrolled. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Hemopexin level was measured by enzyme-linked immunosorbent assay. Muscle quality was evaluated via phase angle (PhA) and grip strength, and sarcopenia status was defined using the Asian Working Group for Sarcopenia criteria. Multiple linear regression models, including sex-stratified analyses, were conducted to determine the relationships of these variables with MMSE scores.

RESULTS

Higher hemopexin levels (β = 1.19, p = 0.017), PhA (β = 0.59, p = 0.005), and grip strength (β = 0.14, p < 0.001) were independently associated with better MMSE scores, whereas sarcopenia was negatively linked to MMSE scores (β = - 2.28, p < 0.001). Notably, sex-stratified models indicated that hemopexin positively predicted MMSE scores in men but not in women; meanwhile, sarcopenia showed a stronger negative impact in women. Educational attainment also displayed a significant positive association with cognitive performance in both sexes.

CONCLUSIONS

In this cross-sectional study of older Japanese adults with cognitive impairment, hemopexin levels and muscle quality emerged as important correlates of cognitive function, particularly in men, while sarcopenia was negatively linked to cognition.

Body mass index changes and trajectories from midlife to late-life: association with subjective cognitive complaints in a 30-year Women's cohort study

BACKGROUND

The relationship between body mass index (BMI) changes across the lifespan and cognitive health in later life remains unclear. This study evaluated the association between BMI changes from midlife to late-life and subsequent subjective cognitive complaints (SCCs) in women.

METHODS

We analysed data from 5160 women in the New York University Women's Health Study, a prospective cohort with over 30 years of follow-up. BMI was calculated using self-reported height and weight at baseline and follow-up. SCCs were assessed using a validated questionnaire in 2018-2020. Odds ratios (ORs) for reporting ≥2 SCCs were estimated using unconditional logistic regression.

RESULTS

BMI at specific life stages was not significantly associated with SCC risk. BMI changes from midlife to late-life were associated with SCC risk. Compared to women with stable BMI (≤5% change), moderate BMI loss (5.1-10% decrease) was associated with higher odds of ≥2 SCCs (OR: 1.23, 95% CI: 1.02-1.48), large BMI gain (>10% increase) was associated with lower odds of ≥2 SCCs (OR: 0.81, 95% CI: 0.67-0.97). These findings were consistent across sensitivity analyses, including varying age cut-offs and excluding BMI changes occurring 5-10 years before late-life.

CONCLUSIONS

Our findings emphasize the importance of considering lifelong weight changes in assessing cognitive health risks. In particular, significant weight loss from midlife to late-life may serve as a potential indicator of cognitive decline in older adults. Further research is needed to elucidate the underlying mechanisms of this association and to explore effective interventions for mitigating cognitive health risks.

[Impact of body composition and psychological state on executive functions in individuals with obesity]

BACKGROUND

This study aimed to examine the relationship between anthropometric and psychological variables and executive functions in individuals with obesity.

METHOD

Adults with obesity were recruited in Alicante (Spain). Participants underwent interviews to collect sociodemographic data (sex, age, educational level, marital status, and employment status) and anthropometric assessments measuring weight, body mass index, visceral fat, fat mass, and muscle mass. Psychological evaluations were carried out using the DASS-21. Executive functions were assessed through the M-WCST (cognitive flexibility), WAIS-IV (working memory), TMTA (processing speed), and TMTB (inhibitory control).

RESULTS

The sample comprised 48 participants (52% female) with a mean age of 47.58 years. Most participants had secondary education, were married, and employed. Women exhibited higher values in weight, body mass index, and fat mass (% and kg). Multiple linear regression analyses revealed that anthropometric variables -weight, body mass index, visceral fat, fat mass, and muscle mass- significantly influenced performance on working memory, processing speed, and inhibitory control performance. Additionally, anxiety levels were associated with cognitive flexibility and working memory, while depression levels were linked to inhibitory control.

CONCLUSIONS

Anthropometric variables -weight, body mass index, visceral fat, fat mass, and muscle mass- are associated with variations in executive function performance, particularly in working memory, processing speed, and inhibitory control. Psychological states -anxiety and depression- are related to specific aspects of executive functioning.

Associated factors of sarcopenia among urban community-dwelling older adults in West Jakarta: A cross-sectional study

Introduction

Sarcopenia has many risk factors and an increased likelihood of adverse effects. However, the exact mechanism of how these risk factors cause sarcopenia remains to be elucidated. This study aimed to evaluate the association between physical components, olfactory function impairment and sarcopenia in urban communities.

Methods

This cross-sectional study involved 334 participants aged 60 years and above residing in urban villages in West Jakarta. The medical history, physical ability, cognitive function and olfactory function of participants were examined. Physical ability was assessed based on activities of daily living and instrumental activities of daily living (IADLs). Regarding olfactory function, six scratch test-type odours common in Indonesia were used. Sarcopenia was measured based on muscle mass, muscle strength and physical performance. Binary logistic analysis and backward logistic regression analysis were utilised to explore the association of sarcopenia with the other variables.

Results

Sarcopenia was significantly associated with older age (adjusted odds ratio [AOR]=2.613, 95% confidence interval [CI] = 1.471-4.640), obesity (AOR=0.190 (0.110-0.329), impaired olfactory function (AOR=1.822, 95% CI=1.086-3.056) and frailty (AOR=3.117, 95% CI=1.375-7.064).

Conclusion

The associated factors of sarcopenia include olfactory function, older age, unemployment, impaired IADLs, obesity and frailty.

Research progress on resistance exercise therapy for improving cognitive function in patients with AD and muscle atrophy

Alzheimer's disease (AD) significantly reduces the quality of life of patients and exacerbates the burden on their families and society. Resistance exercise significantly enhances the overall cognitive function of the elderly and patients with AD while positively improving memory, executive function, and muscle strength, reducing fall risks, and alleviating psychological symptoms. As AD is a neurodegenerative disorder, some nerve factors are readily activated and released during exercise. Therefore, several prior studies have concentrated on exploring the molecular mechanisms of resistance exercise and their impact on brain function and neural plasticity. Recent investigations have identified an intrinsic relationship between individuals with AD and the pathological mechanisms of skeletal muscle atrophy, establishing a correlation between patients with AD cognitive level and skeletal muscle content. Resistance exercise primarily targets the skeletal muscle, which improves cognitive impairment in patients with AD by reducing vascular and neuroinflammatory factors and further enhances cognitive function in patients with AD by restoring the structural function of skeletal muscle. Furthermore, the effects of resistance training vary among distinct subgroups of cognitive impairment. Individuals exhibiting lower cognitive function demonstrate more pronounced adaptive responses in physical performance over time. Consequently, further investigation is warranted to determine whether tailored guidelines-such as variations in the frequency and duration of resistance exercise-should be established for patients with varying levels of dementia, in order to optimize the benefits for those experiencing cognitive impairment. This study aimed to review the relationship between AD and skeletal muscle atrophy, the impact of skeletal muscle atrophy on AD cognition, the mechanism by which resistance exercise improves cognition through skeletal muscle improvement, and the optimal resistance exercise mode to elucidate the additional advantages of resistance exercise in treating cognitive function in patients with AD and skeletal muscle atrophy.

Vascular dysfunction in Alzheimer's disease: Exploring the potential of aerobic and resistance exercises as therapeutic strategies

Alzheimer's disease (AD) is the leading cause of morbidity and mortality worldwide, as a result of cognitive decline and neurological dysfunction. In AD, reduced cerebral blood flow and impaired vascularization result from capillary bed degeneration and decreased angiogenesis, as observed in both patients and animal models. Physical exercise is recognized as a potential intervention to delay AD progression and reduce disease risk. While most studies have focused on the benefits of aerobic exercise (AE), emerging evidence suggests that resistance exercise (RE) also exerts positive effects on overall health and cognitive function in aging and AD. However, a notable gap in knowledge remains regarding the effects of RE on cerebral blood flow and vascular structure. This review explores the processes by which AE and RE influence brain vascularization in aging and AD, including blood flow, endothelial function, angiogenesis and neurotrophic factor levels. Based on pre-clinical and clinical studies, we conclude that both AE and RE contribute to improved cerebral blood flow and vascular function, promoting vascular repair in the aging and AD-affected brain. By examining the relationship between exercise modalities and brain vascularization, this review expands knowledge regarding the processes underlying the neuroprotective effects of exercise in neurodegenerative and aging conditions.

Chronic musculoskeletal pain and its association with cognitive function and sarcopenia in older adults: Characterization and change over three months

Pain, cognitive impairment, and sarcopenia share common risk factors and neurophysiological processes, but studies investigating cognition and sarcopenia in older adults with pain are scarce. This study's main aim was to compare cognition and sarcopenia between older adults with and without chronic pain. A secondary aim was to investigate predictors of cognition and sarcopenia at baseline and 3 months while adjusting for confounders. Participants (67 older adults with pain and 67 asymptomatic older adults) were assessed for sociodemographic and clinical information, pain (number of painful body sites - body chart, pain phenotype - PainDETECT, severity and disability - BPI, pain catastrophizing - PCS, and kinesiophobia - Tampa Scale), cognition (MoCA), sarcopenia (risk of sarcopenia - SARC-F, hand grip strength, and calf circumference) and physical activity (RAPA) at baseline and 3 months after. Older adults with and without pain did not differ in cognition (Mean (95% CI): Pain = 21.47 (20.60; 22.34); Asymptomatic = 21.75 (20.89; 22.61)), but older adults with pain had greater signs of sarcopenia than asymptomatic older adults, including higher risk of sarcopenia (Mean (95%CI): Pain=2.89 (2.41; 3.37); Asymptomatic=0.50 (0.32; 0.68)) and lower hand grip strength (Pain=24.01 (21.74; 26.29); Asymptomatic=27.98 (25.80; 30.16)). No between-group differences were found for calf circumference (Pain=35.03 (34.26; 35.79); Asymptomatic=34.55 (33.86; 35.24)). Pain phenotype (baseline) and kinesiophobia (3 months) contributed to poorer cognition. Kinesiophobia and catastrophizing (baseline), and pain severity (3 months) contributed to sarcopenia. Despite no differences in cognition between older adults with and without pain, pain-related variables contributed to explaining sarcopenia and cognition. PERSPECTIVE: This study compared cognition and sarcopenia between older adults with and without pain and explored the association between pain, cognition, and sarcopenia. Groups were similar for cognition, but older adults with pain showed higher signs of sarcopenia. Kinesiophobia and pain severity partially explained cognition and sarcopenia among those with pain.

APOE4 Exerts Partial Diet-dependent Effects on Energy Expenditure and Skeletal Muscle Mitochondrial Pathways in a Preclinical Model

Apolipoprotein E4 (APOE4) is the greatest genetic risk factor for Alzheimer's (AD) and is linked to whole-body metabolic dysfunction. However, it is unclear how APOE4 interacts with modifiable factors like diet to impact tissues central to regulating whole-body metabolism. We examined APOE4- and Western diet-driven effects in skeletal muscle using APOE3 (control) and APOE4 targeted replacement mice on a C57BL/6NTac background fed a high-fat diet (HFD, 45% kcal fat) or low-fat diet (LFD, 10% kcal fat) for 4 months (n = 7-8 per genotype/diet/sex combination). We assessed body composition and whole-body outcomes linked to skeletal muscle function including respiratory exchange ratio (RER) and resting energy expenditure (REE). In skeletal muscle, we evaluated the proteome and mitochondrial respiration. In males only, APOE4 drove greater gains in fat mass and lower gains in lean mass on both diets. APOE4 did not affect daily RER but was associated with elevated REE in males and lower REE in HFD females after covarying for body composition. Skeletal muscle proteomics showed APOE4 exerts several diet- and sex-specific effects on mitochondrial pathways, including elevations in branched-chain amino catabolism in HFD males and reductions in oxidative phosphorylation in LFD females. This did not translate to differences in skeletal muscle mitochondrial respiration, suggesting that compensatory mechanisms may sustain mitochondrial function at this age. Our work indicates that genetic risk may mediate early life effects on skeletal muscle mitochondria and energy expenditure that are partially dependent on diet. This has important implications for mitigating ad risk in APOE4 carriers.

Body composition differences in older adults with and without Alzheimer's disease: A systematic review and meta-analysis of observational studies

BACKGROUND

Research on body composition and fat distribution in Alzheimer's disease (AD) has presented conflicting findings.

OBJECTIVE

Compare body composition and anthropometric measurements in older adults with and without AD.

METHODS

A systematic review and meta-analysis were conducted following Cochrane guidelines and PRISMA standards. MEDLINE, Embase, Scopus, LILACS, WPRIM, and the Spanish Bibliographic Index of Health Sciences were searched up to September 2024, considering observational studies that compared body composition between AD groups and controls. Outcomes included body fat percentage, body mass index (BMI), impedance, resistance, and reactance. The methodological quality and level of evidence were assessed using the Joanna Briggs Institute scale and GRADE, respectively. A random-effects meta-analysis model was used to calculate mean differences (MD).

RESULTS

Fourteen studies involving 2761 older adults were included. Older adult women with AD showed a lower body fat percentage (p < 0.01; MD = -5.07) and BMI (p = 0.05; MD = -1.28) compared to controls. Older adult men with AD had higher impedance (p = 0.01; MD = 2.05), resistance (p = 0.02; MD = 45.10), and lower reactance (p = 0.03; MD = -2.05) compared to controls. No significant differences in body fat percentage or BMI were found between older adults with and without AD, regardless of gender.

CONCLUSIONS

Women with AD showed lower body fat percentage and BMI, while men with AD had higher impedance, resistance, and lower reactance. These factors should be included in geriatric assessments for AD patients, though further research is needed to understand their link to cognitive outcomes in AD.

Association of body composition with neuroimaging biomarkers and cognitive function; a population-based study of 70-year-olds

BACKGROUND

A better understanding of body-brain links may provide insights on targets for preventing cognitive decline. The aim was to explore associations of body composition with neuroimaging biomarkers and cognitive function among dementia-free 70-year-olds.

METHODS

Dual-energy X-ray absorptiometry body composition measures in relation to neuroimaging measures of cortical thickness, hippocampal volume, small vessel disease, predicted brain age, and cognitive performance were explored in a cross-sectional study of 674 dementia-free 70-year-olds from the Swedish Gothenburg H70 Birth Cohort study. Linear or ordinal regression analyses were performed.

FINDINGS

Higher quantity of muscle mass was associated with lower predicted brain age (β: -0.31 [95% CI: -0.45, -0.16], p: 0.00013). Those with normal level muscle mass (>7.0 men, >5.5 women kg/height m2) had overall thicker cortex (β: 0.043 [95% CI: 0.023, 0.064], p: 0.00016), thicker cortex in Alzheimer's disease signature regions (β: 0.051 [95% CI: 0.025, 0.076], p: 0.00040), and larger hippocampal volume (β: 111.52 [95% CI: 25.28, 197.75], p: 0.030) compared to those with sarcopenic level muscle mass. Higher accumulation of visceral fat was associated with overall thinner cortex (β: -0.017 [95% CI: -0.028, -0.005], p: 0.024). Faster gait speed and higher handgrip strength were associated with indicators of better brain health.

INTERPRETATION

Improving muscle mass fitness and lower visceral fat may be beneficial for brain health. Intervention studies are needed to confirm that targeting body composition can promote healthy brain ageing and reduce the risk of cognitive impairment among older adults.

FUNDING

The Swedish Research Council, Hjärnfonden, and Alzheimerfonden.

Differences in lean mass and sarcopenia between individuals with Alzheimer's disease and those without dementia: A systematic review and meta-analysis of observational studies

BACKGROUND

Studies have observed that individuals with Alzheimer's disease (AD) tend to have lower lean mass and higher rates of sarcopenia.

OBJECTIVE

This review aims to assess differences in lean mass, sarcopenia, and its components between individuals with AD and those without dementia (WD).

METHODS

Searches were conducted in the Medline, Web of Science, Embase, Scopus and Latin American and Caribbean Health Scientific Literature. Observational studies comparing lean mass, sarcopenia, and its components in the populations of interest were included. We used the Joanna Briggs Institute (JBI) scale to assess methodological quality. Mean differences (MD) and standardized mean differences were calculated for the meta-analyses.

RESULTS

Four studies with 2035 individuals found that those with AD had significantly lower upper and lower limb lean mass, and skeletal muscle mass index compared to WD individuals. AD individuals also had a higher sarcopenia prevalence (41.33% versus 20.66%) and significant reductions in handgrip strength, lower limb muscle strength, and gait speed compared to WD individuals. The JBI scale analysis showed high agreement among the studies (k = 1.00, p = 0.046).

CONCLUSIONS

Individuals with AD have lower lean mass, higher rates of sarcopenia, and reduced muscle function compared to those without dementia. While the results suggest the need for early screening programs and integrated therapeutic interventions to improve clinical outcomes and quality of life for individuals with AD, it is important to consider that biases inherent in observational studies may compromise the quality of the evidence. Therefore, further research, preferably clinical trials, is needed to confirm these associations.

Skeletal muscle proteome differs between young APOE3 and APOE4 targeted replacement mice in a sex-dependent manner

Introduction

Apolipoprotein E4 (APOE4) is the strongest genetic risk factor for Alzheimer's disease (AD), yet it's unclear how this allele mediates risk. APOE4 carriers experience reduced mobility and faster decline in muscle strength, suggesting skeletal muscle involvement. Mitochondria are critical for muscle function and although we have reported defects in muscle mitochondrial respiration during early cognitive decline, APOE4-mediated effects on muscle mitochondria are unknown.

Methods

Here, we sought to determine the impact of APOE4 on skeletal muscle bioenergetics using young, male and female APOE3 (control) and APOE4 targeted replacement mice (n = 8 per genotype/sex combination). We examined the proteome, mitochondrial respiration, fiber size, and fiber-type distribution in skeletal muscle.

Results

We found that APOE4 alters mitochondrial pathway expression in young mouse muscle in a sex-dependent manner without affecting respiration and fiber size or composition relative to APOE3. In both sexes, the expression of mitochondrial pathways involved in electron transport, ATP synthesis, and heat production by uncoupling proteins and mitochondrial dysfunction significantly differed between APOE4 and APOE3 muscle. For pathways with predicted direction of activation, electron transport and oxidative phosphorylation were upregulated while mitochondrial dysfunction and sirtuin signaling were downregulated in female APOE4 vs. APOE3 muscle. In males, sulfur amino acid metabolism was upregulated in APOE4 vs. APOE3 muscle.

Discussion

This work highlights early involvement of skeletal muscle in a mouse model of APOE4-linked AD, which may contribute to AD pathogenesis or serve as a biomarker for brain health.

Identification of Predictors of Sarcopenia in Older Adults Using Machine Learning: English Longitudinal Study of Ageing

Background: After its introduction in the ICD-10-CM in 2016, sarcopenia is a condition widely considered to be a medical disease with important consequences for the elderly. Considering its high prevalence in older adults and its detrimental effects on health, it is essential to identify its risk factors to inform targeted interventions. Methods: Taking data from wave 2 of the ELSA, using ML-based methods, this study investigates which factors are significantly associated with sarcopenia. The Minimum Redundancy Maximum Relevance algorithm has been used to allow for an optimal set of features that could predict the dependent variable. Such a feature is the input of a ML-based prediction model, trained and validated to predict the risk of developing or not developing a disease. Results: The presented methods are suitable to identify the risk of acquired sarcopenia. Age and other relevant features related with dementia and musculoskeletal conditions agree with previous knowledge about sarcopenia. The present classifier has an excellent performance since the "true positive rate" is 0.81 and the low "false positive rate" is 0.26. Conclusions: There is a high prevalence of sarcopenia in elderly people, with age and the presence of dementia and musculoskeletal conditions being strong predictors. The new proposed approach paves the path to test the prediction of the incidence of sarcopenia in older adults.

Alzheimer's Disease: Understanding Motor Impairments

Alzheimer's disease (AD), the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, profoundly impacts health and quality of life. While cognitive impairments-such as memory loss, attention deficits, and disorientation-predominate in AD, motor symptoms, though common, remain underexplored. These motor symptoms, including gait disturbances, reduced cardiorespiratory fitness, muscle weakness, sarcopenia, and impaired balance, are often associated with advanced stages of AD and contribute to increased mortality. Emerging evidence, however, suggests that motor symptoms may be present in earlier stages and can serve as predictive markers for AD in older adults. Despite a limited understanding of the underlying mechanisms driving these motor symptoms, several key pathways have been identified, offering avenues for further investigation. This review provides an in-depth analysis of motor symptoms in AD, discussing its progression, potential mechanisms, and therapeutic strategies. Addressing motor symptoms alongside cognitive decline may enhance patient functionality, improve quality of life, and support more comprehensive disease management strategies.

Hypothalamic atrophy and structural covariance in amnestic mild cognitive impairment and Alzheimer's dementia

BACKGROUND

Alzheimer's disease (AD) is characterized by progressive cognitive decline and specific brain atrophy patterns, primarily involving the medial temporal lobes. A number of studies have discussed hypothalamic involvement in AD with consecutive metabolic and/or autonomic disturbances yet only few studies have investigated hypothalamic atrophy in AD and its early stages in particular.

METHODS

We applied semi-automated volumetry of the hypothalamus (HTH) in 3 T MRI in a sample N = 175 participants [age 74.9 ± 7.22; gender 85 m/90f; cognitively normal controls (CN; N = 56); amnestic mild cognitive impairment (MCI; N = 78); AD (N = 41)] from the Alzheimer's Disease Neuroimaging Initiative (ADNI). In addition, we used voxel-based morphometry (VBM), cortical thickness (CTH) analyses and source-based morphometry (SBM) derived networks of structural covariance to investigate brain structural covariance patterns of the HTH under consideration of diagnostic groups, β-amyloid (AB) positivity and apolipoprotein E (APOE) ε4 status.

RESULTS

Hypothalamic atrophy was observed in both early and advanced disease stages (i.e. hypothalamic volume CN > MCI > AD). VBM, CTH analysis and SBM revealed positive associations between hypothalamic volume (HV) and AD-vulnerable regions, largely corresponding to the Papez circuit and brain regions implicated in autonomic regulation, however, group differences regarding HTH structural covariance were not observed. Similar observations were made in carriers and non-carriers of the ε4 allele, yet more pronounced in ε4 carriers. Although not reaching significance, comparisons of AB positive vs. negative subjects indicated stronger HTH atrophy in biomarker positive participants. HV was not associated with body mass index or longitudinal weight change.

CONCLUSIONS

Our findings support early structural changes of the HTH in AD. HV covaries with regional volumes of AD-vulnerable regions. This could point to secondary atrophy of the HTH following atrophy of the hippocampus and other structures of the Papez circuit in AD.

Association between probable sarcopenia and dementia risk: a prospective cohort study with mediation analysis

The role of alcohol consumption as a mediator in the risk between sarcopenia and dementia remains inadequately studied. There is currently limited research on whether the association between sarcopenia and the risk of Alzheimer's disease (AD) is influenced by genetic susceptibility. Our study incorporated a total of 483,637 baseline non-dementia participants, who were classified into groups of individuals with no sarcopenia and those with probable sarcopenia based on the definition. We employed Cox proportional hazards models to evaluate the association between probable sarcopenia and the risk of all cause dementia (ACD), AD, and vascular dementia (VD). We conducted mediation analysis to explore the role of alcohol consumption in the association between probable sarcopenia and the risk of ACD, AD, and VD. During the median follow-up period of 13.6 years, we documented 9000 new cases of ACD (including 4061 AD and 2025 VD). Fully adjusted multivariate model revealed a significant correlation between probable sarcopenia and elevated risk for ACD (HR = 1.54, 95% CI: 1.46-1.62, p < 0.001), AD (HR = 1.32, 95% CI: 1.21-1.43, p < 0.001), and VD (HR = 1.69, 95% CI: 1.52-1.89, p < 0.001). Mediation analysis elucidates that alcohol consumption explained 12.8%, 15.2%, and 11.1% of the associations of probable sarcopenia with the risk of ACD, AD, and VD, respectively. An interactive relationship prevails between probable sarcopenia and genetic factors (p for interaction <0.001), and regardless of the degree of genetic risk, probable sarcopenia correlates with an elevated AD risk. Our study reveals a significant association between probable sarcopenia and an increased risk of dementia, with alcohol consumption playing a mediating role in this association. There is an interaction between probable sarcopenia and genetic susceptibility related to the risk of AD.

Interactions between muscle volume and body mass index on brain structure in the UK Biobank

Background

Low skeletal muscle volume may increase dementia risk through mechanisms affecting brain structure. However, it is unclear whether this relationship exists outside of sarcopenia and/or varies by other factors. We aimed to study the interplay between skeletal muscle volume and factors, such as age, sex, and body mass index (BMI), in explaining brain structure at midlife in a cohort without sarcopenia.

Methods

We used abdominal and brain magnetic resonance imaging (MRI) data from a population-based cohort enrolled in the UK Biobank. The following measures were derived: thigh fat-free muscle volume (FFMV), total brain volume (TBV), gray matter volume (GMV), white matter volume (WMV), total hippocampal volume (THV), and white matter hyperintensity volume (WMHV). Participants below sex-based grip strength thresholds suggesting probable sarcopenia were excluded. Linear regression analysis was used to study the interaction or mediation effects of age, sex, and BMI on the associations between FFMV and brain volumes.

Results

Data were available for 20,353 participants (median age 64 years, 53% female). We found interactions between thigh FFMV, BMI, and age (all p < 0.05). Greater thigh FFMV was associated with better brain volumes in those aged <64 years with normal (TBV: β = 2.0 ml/L, p = 0.004; GMV: β = 0.8 ml/L, p = 0.04; WMV: β = 1.1 ml/L, p = 0.006; WMHV: β = -0.2 ml/L, p = 3.7 × 10-5) or low BMI (TBV: β = 21.2 ml/L, p = 0.003; WMV: β = 13.3 ml/L, p = 0.002, WMHV: β = -1.1 ml/L, p = 0.04).

Conclusion

Greater thigh muscle volume correlates with better brain volumes at midlife in people without sarcopenia, but this relationship weakens with greater age and BMI. Further study is required to investigate the underlying mechanisms to understand which components of body composition are potentially modifiable risk factors for dementia.

Sarcopenia is a predictor for Alzheimer's continuum and related clinical outcomes

Low body mass index is closely related to a high risk of Alzheimer's disease (AD) and related biomarkers including amyloid-β (Aβ) deposition. However, the association between sarcopenia and Aβ-confirmed AD remains controversial. Therefore, we investigated the relationship between sarcopenia and the AD continuum. We explored sarcopenia's association with clinical implications of participants on the AD continuum. We prospectively enrolled 142 participants on the AD continuum (19 with preclinical AD, 96 with mild cognitive impairment due to AD, and 28 with AD dementia) and 58 Aβ-negative cognitively unimpaired participants. Sarcopenia, assessed using dual-energy X-ray absorptiometry and hand grip measurements, was considered a predictor. AD continuum, defined by Aβ deposition on positron emission tomography served as an outcome. Clinical severity in participants on the AD continuum assessed using hippocampal volume, Mini-Mental State Examination (MMSE), Seoul Verbal Learning Test (SVLT), and Clinical Dementia Rating Scale Sum of Boxes Scores (CDR-SOB) were also considered an outcome. Sarcopenia (odds ratio = 4.99, p = 0.004) was associated independently with the AD continuum after controlling for potential confounders. Moreover, sarcopenia was associated with poor downstream imaging markers (decreased hippocampal volume, β = - 0.206, p = 0.020) and clinical outcomes (low MMSE, β = - 1.364, p = 0.025; low SVLT, β = - 1.077, p = 0.025; and high CDR-SOB scores, β = 0.783, p = 0.022) in participants on the AD continuum. Sarcopenia was associated with the AD continuum and poor clinical outcome in individuals with AD continuum. Therefore, our results provide evidence for future studies to confirm whether proper management of sarcopenia can effective strategies are required for sarcopenia management to prevent the AD continuum and its clinical implications.

Associations between Cognitive Impairment, Weight Status and Comorbid Conditions in Hospitalized Adults of 55 Years and Older in Guadeloupe

Cognitive decline and comorbid conditions commonly co-occur, and these conditions can affect cognitive health. We aimed to estimate the prevalence of cognitive impairment (CI) according to weight status and to evaluate the associations between CI, weight status and comorbid conditions in adults of 55 years and older. The Abbreviated Mental Test Score (AMTS) was used. Logistic regressions were performed. Overall, 415 individuals were included. The mean age was 75.7 ± 10.1 years, and the mean BMI was 26.2 ± 6.9 kg/m2. The prevalence of CI was 20.7% in the whole study group and 31%, 24.8%, 17.7% and 10.2% in underweight, normal weight, overweight and obese individuals, respectively; p < 0.004. The low folate, vitamin D and prealbumin levels were more frequently found in individuals with CI compared with those without CI. Compared with the obese individuals, a higher odds ratio of prevalent CI was noted for underweight individuals OR 3.89 (95% CI 1.54-9.80); p = 0.004. Additionally, male gender, older age, stroke, having three or more comorbid conditions and findings of undernutrition were significantly associated with CI. Being underweight was associated with an increased risk of CI. Prevention strategies including the monitoring of nutritional status may help to prevent cognitive decline and promote healthy aging.

Accelerated sarcopenia precedes learning and memory impairments in the P301S mouse model of tauopathies and Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) impairs cognitive functions and peripheral systems, including skeletal muscles. The PS19 mouse, expressing the human tau P301S mutation, shows cognitive and muscular pathologies, reflecting the central and peripheral atrophy seen in AD.

METHODS

We analysed skeletal muscle morphology and neuromuscular junction (NMJ) through immunohistochemistry and advanced image quantification. A factorial Analysis of Variance assessed muscle weight, NCAM expression, NMJ, myofibre type distribution, cross-sectional areas, expression of single or multiple myosin heavy-chain isoforms, and myofibre grouping in PS19 and wild type (WT) mice over their lifespan (1-12 months).

RESULTS

Significant weight differences in extensor digitorum longus (EDL) and soleus muscles between WT and PS19 mice were noted by 7-8 months. For EDL muscle in females, WT weighed 0.0113 ± 0.0005 compared with PS19's 0.0071 ± 0.0008 (P < 0.05), and in males, WT was 0.0137 ± 0.0001 versus PS19's 0.0069 ± 0.0006 (P < 0.005). Similarly, soleus muscle showed significant differences; females (WT: 0.0084 ± 0.0004; PS19: 0.0057 ± 0.0005, P < 0.005) and males (WT: 0.0088 ± 0.0003; PS19: 0.0047 ± 0.0004, P < 0.0001). Analysis of the NMJ in PS19 mice revealed a marked reduction in myofibre innervation at 5 months, with further decline by 10 months. NMJ pre-terminals in PS19 mice became shorter and simpler by 5 months, showing a steep decline by 10 months. Genotype and age strongly influenced muscle NCAM immunoreactivity, denoting denervation as early as 5-6 months in EDL muscle Type II fibres, with earlier effects in soleus muscle Type I and II fibres at 3-4 months. Muscle denervation and subsequent myofibre atrophy were linked to a reduction in Type IIB fibres in the EDL muscle and Type IIA fibres in the soleus muscle, accompanied by an increase in hybrid fibres. The EDL muscle showed Type IIB fibre atrophy with WT females at 1505 ± 110 μm2 versus PS19's 1208 ± 94 μm2, and WT males at 1731 ± 185 μm2 versus PS19's 1227 ± 116 μm2. Similarly, the soleus muscle demonstrated Type IIA fibre atrophy from 5 to 6 months, with WT females at 1194 ± 52 μm2 versus PS19's 858 ± 62 μm2, and WT males at 1257 ± 43 μm2 versus PS19's 1030 ± 55 μm2. Atrophy also affected Type IIX, I + IIA, and IIA + IIX fibres in both muscles. The timeline for both myofibre and overall muscle atrophy in PS19 mice was consistent, indicating a simultaneous decline.

CONCLUSIONS

Progressive and accelerated neurogenic sarcopenia may precede and potentially predict cognitive deficits observed in AD.

Association of changes in predicted body composition with subsequent risk of dementia

OBJECTIVE

The effect of body composition change on the risk of dementia is not clear. This study analyzed the associations of changes in predicted lean body mass index (pLBMI), predicted appendicular skeletal muscle mass index (pASMI), and predicted body fat mass index (pBFMI) with the risk of dementia.

METHODS

In this nationwide cohort study, data were obtained from the Korean National Health Insurance Service database. The exposure was defined as changes in pLBMI, pASMI, and pBFMI derived from validated prediction equations. The outcome was dementia, defined based on the dementia diagnosis with prescription of anti-dementia medication. Cox proportional hazards regression analyses were performed to obtain the hazard ratio with a 95% confidence interval for risk of dementia according to changes in predicted body composition.

RESULTS

A total of 13,215,208 individuals with no prior record of dementia who underwent health screenings twice between 2009-2010 and 2011-2012 were included. A 1-kg/m2 increase in pLBMI and pASMI had an association with reduced risk of dementia (aHR: 0.85, 95% CI 0.84-0.87; aHR: 0.70, 95% CI 0.69-0.72, respectively for men, and aHR: 0.69, 95% CI 0.67-0.71; aHR: 0.59, 95% CI 0.57-0.61, respectively for women). A 1-kg/m2 increase in pBFMI had an association with a raised risk of dementia (aHR: 1.19, 95% CI 1.17-1.21 for men and aHR: 1.53, 95% CI 1.48-1.57 for women). These results remained consistent regardless of sex or weight change.

INTERPRETATION

Increase in pLBMI or pASMI, or reduction in pBFMI was linked to lower risk of dementia.

Association Between Mid-arm Muscle Circumference and Cognitive Function: A Longitudinal Study of Chinese Adults

BACKGROUND

Dementia affects 55 million people worldwide and low muscle mass may be associated with cognitive decline. Mid-arm muscle circumference (MAMC) correlates with dual-energy Xray absorptiometry and bioelectrical impedance analyses, yet are not routinely available. Therefore, we examined the association between MAMC and cognitive performance in older adults.

METHODS

We included community-dwelling adults ≥55 years from the China Health and Nutrition Survey. Cognitive function was estimated based on a subset of the modified Telephone Interview for Cognitive Status (0-27, low-high) during years (1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011, 2015, 2018). A multivariable linear mixed-effects model was used to test whether MAMC was associated with rate of cognitive decline across age groups and cognitive function overall.

RESULTS

Of 3702 adults (53% female, 63.2 ± 7.3 years), mean MAMC was 21.4 cm ± 3.0 and baseline cognitive score was 13.6 points ±6.6. We found no evidence that the age-related rate of cognitive decline differed by MAMC (P = .77). Declines between 5-year age groups ranged from -.80 [SE (standard error) .18] to -1.09 [.22] for those at a mean MAMC, as compared to -.86 [.25] to -1.24 [.31] for those at a 1 MAMC 1 standard deviation above the mean. Higher MAMC was associated with better cognitive function with .13 [.06] higher scores for each corresponding 1 standard deviation increase in MAMC across all ages.

CONCLUSION

Higher MAMC at any age was associated with better cognitive performance in older adults. Understanding the relationship between muscle mass and cognition may identify at-risk subgroups needing targeted interventions to preserve cognition.

Association between grip strength and electrical properties measured by bioimpedance spectroscopy in women with dementia aged 77 to 97 years living in group homes

Electrical properties estimated from the electrical resistance of the human body can serve as indicators of muscle tissue status and the risk of developing sarcopenia; however, to date, at least to the best of our knowledge, no studies have performed such an assessment in older individuals with advanced dementia. The present study examined the associations between grip strength, body composition and electrical properties using bioimpedance spectroscopy (BIS) in women aged 77-97 years residing in dementia group homes. A total of 33 participants were enrolled with an average age of 88.1±5.2 years; 57.6% of the participants had moderate or severe dementia. The resistance values of the participants were measured in the whole body, upper limbs and lower limbs using BIS, and their body composition, muscle mass index and electrical properties were estimated as indicators of muscle quality. In addition, grip strength was measured and the participants were classified into three groups (high, low and non-measurable) according to their cognitive function. The effect size (partial eta-squared and Cohen's d) was also evaluated. The Shapiro-Wilk test was used to assess the distribution of each variable; variables with non-normal distributions were analyzed following log transformation. Continuous variables were analyzed using a one-way analysis of variance and the Tukey-Kramer post hoc test was used. The post hoc sample size (statistical power: 1-β) analysis revealed a power of ~80% (i.e., 76.1-88.7%), considering the minimum power for sufficient participants. No differences were found in body composition or muscle mass index among the three grip strength groups. As regards the upper limbs, the electrical properties of the characteristic frequencies were significant (P=0.006; effect size, large), and the membrane capacitance (P=0.005; effect size, large) was significantly higher in the high-dose group than in the other groups. A significant association was detected among grip strength, upper limb characteristic frequency and membrane capacitance. Hence, electrical properties may be an indicator of muscle quality in older women identified as needing care for dementia.

Resistance Exercise Training as a New Trend in Alzheimer's Disease Research: From Molecular Mechanisms to Prevention

Alzheimer's disease is a pathology characterized by the progressive loss of neuronal connections, which leads to gray matter atrophy in the brain. Alzheimer's disease is the most prevalent type of dementia and has been classified into two types, early onset, which has been associated with genetic factors, and late onset, which has been associated with environmental factors. One of the greatest challenges regarding Alzheimer's disease is the high economic cost involved, which is why the number of studies aimed at prevention and treatment have increased. One possible approach is the use of resistance exercise training, given that it has been shown to have neuroprotective effects associated with Alzheimer's disease, such as increasing cortical and hippocampal volume, improving neuroplasticity, and promoting cognitive function throughout the life cycle. However, how resistance exercise training specifically prevents or ameliorates Alzheimer's disease has not been fully characterized. Therefore, the aim of this review was to identify the molecular basis by which resistance exercise training could prevent or treat Alzheimer's disease.

Appendicular lean mass and the risk of stroke and Alzheimer's disease: a mendelian randomization study

BACKGROUND

Appendicular lean mass (ALM) is a good predictive biomarker for sarcopenia. And previous studies have reported the association between ALM and stroke or Alzheimer's disease (AD), however, the causal relationship is still unclear, The purpose of this study was to evaluate whether genetically predicted ALM is causally associated with the risk of stroke and AD by performing Mendelian randomization (MR) analyses.

METHODS

A two-sample MR study was designed. Genetic variants associated with the ALM were obtained from a large genome-wide association study (GWAS) and utilized as instrumental variables (IVs). Summary-level data for stroke and AD were generated from the corresponding GWASs. We used random-effect inverse-variance weighted (IVW) as the main method for estimating causal effects, complemented by several sensitivity analyses, including the weighted median, MR-Egger, and MR-pleiotropy residual sum and outlier (MR-PRESSO) methods. Multivariable analysis was further conducted to adjust for confounding factors, including body mass index (BMI), type 2 diabetes mellitus (T2DM), low density lipoprotein-C (LDL-C), and atrial fibrillation (AF).

RESULTS

The present MR study indicated significant inverse associations of genetically predicted ALM with any ischemic stroke ([AIS], odds ratio [OR], 0.93; 95% confidence interval [CI], 0.89-0.97; P = 0.002) and AD (OR, 090; 95% CI 0.85-0.96; P = 0.001). Regarding the subtypes of AIS, genetically predicted ALM was related to the risk of large artery stroke ([LAS], OR, 0.86; 95% CI 0.77-0.95; P = 0.005) and small vessel stroke ([SVS], OR, 0.80; 95% CI 0.73-0.89; P < 0.001). Regarding multivariable MR analysis, ALM retained the stable effect on AIS when adjusting for BMI, LDL-C, and AF, while a suggestive association was observed after adjusting for T2DM. And the estimated effect of ALM on LAS was significant after adjustment for BMI and AF, while a suggestive association was found after adjusting for T2DM and LDL-C. Besides, the estimated effects of ALM were still significant on SVS and AD after adjustment for BMI, T2DM, LDL-C, and AF.

CONCLUSIONS

The two-sample MR analysis indicated that genetically predicted ALM was negatively related to AIS and AD. And the subgroup analysis of AIS revealed a negative causal effect of genetically predicted ALM on LAS or SVS. Future studies are required to further investigate the underlying mechanisms.

Temporal Muscle Thickness: A Practical Approximation for Assessing Muscle Mass in Older Adults

OBJECTIVE

Ongoing research has evidenced the importance of muscle measurement in predicting adverse outcomes. Measurement of other muscles is promising in current research. This study aimed to determine the correlation between temporal muscle thickness (TMT) and appendicular lean soft tissue (ALSTI) in older adults.

DESIGN

Cross-sectional study.

SETTINGS AND PARTICIPANTS

Single cohort gathered in Gothenburg, Sweden, consisting of individuals born in 1944 (n = 1203).

METHODS

We studied 657 magnetic resonance images to measure TMT. Comparisons of TMT with dual-energy X-ray absorptiometry ALSTI (kg/m2) as a reference standard were performed. Finally, TMT associations with cognition evaluated using the Mini-Mental State Examination (MMSE), gait speed, and handgrip strength were explored with linear regressions.

RESULTS

The correlation between TMT and ALSTI was weak yet significant (r = 0.277, P < .001). TMT exhibited significant associations with MMSE (estimate = 0.168, P = .002), gait speed (estimate = 1.795, P < .001), and ALSTI (estimate = 0.508, P < .001). These associations varied when analyzed by sex. In women, TMT was significantly associated with gait speed (estimate = 1.857, P = .005) and MMSE (estimate = 0.223, P = .003). In men, TMT scores were significantly correlated with ALSTI scores (estimate = 0.571, P < .001).

CONCLUSION AND IMPLICATIONS

Repurposing head images can be an accessible alternative to detect muscle mass and ultimately detect sarcopenia. These studies have the potential to trigger interventions or further evaluation to improve the muscle and overall health of individuals. However, additional research is warranted before translating these findings into clinical practice.

Physical activity improves the visual-spatial working memory of individuals with mild cognitive impairment or Alzheimer's disease: a systematic review and network meta-analysis

Objective

Our network meta-analysis aimed to ascertain the effect of physical activity on the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease as well as to propose tailored exercise interventions for each group.

Methods

Employing a frequentist approach, we performed a network meta-analysis to compare the effectiveness of different exercise interventions in improving the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease. Subsequently, we explored the moderating variables influencing the effectiveness of the exercise interventions through a subgroup analysis.

Results

We included 34 articles involving 3,074 participants in the meta-analysis, comprised of 1,537 participants from studies on mild cognitive impairment and 1,537 participants from studies on Alzheimer's disease. The articles included exhibited an average quality score of 6.6 (score studies) and 6.75 (reaction time [RT] studies), all passing the inconsistency test (p > 0.05). In the mild cognitive impairment literature, mind-body exercise emerged as the most effective exercise intervention (SMD = 0.61, 95% CI: 0.07-1.14). In Alzheimer's disease research, aerobic exercise was identified as the optimal exercise intervention (SMD = 0.39, 95% CI: 0.06-0.71).

Conclusion

The results of the subgroup analysis suggest that the most effective approach to enhancing the visual-spatial working memory of individuals with mild cognitive impairment entails exercising at a frequency of three or more times per week for over 60 min each time and at a moderate intensity for more than 3 months. Suitable exercise options include mind-body exercise, multicomponent exercise, resistance exercise, and aerobic exercise. For individuals with Alzheimer's disease, we recommend moderately intense exercise twice per week for over 90 min per session and for a duration of 3 months or longer, with exercise options encompassing aerobic exercise and resistance exercise.

Digging into the intrinsic capacity concept: Can it be applied to Alzheimer's disease?

Historically, aging research has largely centered on disease pathology rather than promoting healthy aging. The World Health Organization's (WHO) policy framework (2015-2030) underscores the significance of fostering the contributions of older individuals to their families, communities, and economies. The WHO has introduced the concept of intrinsic capacity (IC) as a key metric for healthy aging, encompassing five primary domains: locomotion, vitality, sensory, cognitive, and psychological. Past AD research, constrained by methodological limitations, has focused on single outcome measures, sidelining the complexity of the disease. Our current scientific milieu, however, is primed to adopt the IC concept. This is due to three critical considerations: (I) the decline in IC is linked to neurocognitive disorders, including AD, (II) cognition, a key component of IC, is deeply affected in AD, and (III) the cognitive decline associated with AD involves multiple factors and pathophysiological pathways. Our study explores the application of the IC concept to AD patients, offering a comprehensive model that could revolutionize the disease's diagnosis and prognosis. There is a dearth of information on the biological characteristics of IC, which are a result of complex interactions within biological systems. Employing a systems biology approach, integrating omics technologies, could aid in unraveling these interactions and understanding IC from a holistic viewpoint. This comprehensive analysis of IC could be leveraged in clinical settings, equipping healthcare providers to assess AD patients' health status more effectively and devise personalized therapeutic interventions in accordance with the precision medicine paradigm. We aimed to determine whether the IC concept could be extended from older individuals to patients with AD, thereby presenting a model that could significantly enhance the diagnosis and prognosis of this disease.

The causal effect of sarcopenia-associated traits on brain cortical structure: A Mendelian randomization study

BACKGROUND

Previous observational studies have reported sarcopenia can affect the structure and function of brain cortical structure. However, the causality inferred from those studies was subjected to residual confounding and reverse causation. Herein, we use a two-sample Mendelian randomization (MR) analysis to illustrate the causal effect of sarcopenia-associated traits on brain cortical structure.

METHODS

We selected appendicular lean mass (ALM), hand grip strength (left and right) (HGSL and HGSR), and usual walking pace (UWP) to symbolize sarcopenia. The definition of brain cortical structure is human brain cortical surface area (SA) and cortical thickness (TH) globally and in 34 functional regions measured by magnetic resonance imaging. Instrumental variables at the genome-wide significance level were obtained from publicly available datasets, and inverse variance weighted as the primary method was used for MR analysis.

RESULT

At the global level, we found ALM (β=2604.68, 95 % confidence interval (CI): 1886.17 to 3323.19, P = 1.20 × 10-12) and HGSR (β=4733.05, 95 % CI: 2245.08 to 7221.01, P = 1.93 × 10-4) were associated with increased SA. At the region level, the SA of 25 functional gyrus without global weighted was influenced by ALM. The HGSR significantly increased SA of medial orbitofrontal and precentral gyrus without global weighted and ALM was associated with decrease of TH of lateral occipital gyrus with global weighted. No pleiotropy was detected.

CONCLUSION

This was the first MR study investigated the causal effect of sarcopenia-associated traits on brain cortical structure. In our study, we revealed genetically predicted sarcopenia-associated traits including ALM and HGSR could affect brain cortical structure.

Targeted brain-specific tauopathy compromises peripheral skeletal muscle integrity and function

Tauopathies are neurodegenerative disorders in which the pathological intracellular aggregation of the protein tau causes cognitive deficits. Additionally, clinical studies report muscle weakness in populations with tauopathy. However, whether neuronal pathological tau species confer muscle weakness, and whether skeletal muscle maintains contractile capacity in primary tauopathy remains unknown. Here, we identified skeletal muscle abnormalities in a mouse model of primary tauopathy, expressing human mutant P301L-tau using adeno-associated virus serotype 8 (AAV8). AAV8-P301L mice showed grip strength deficits, hyperactivity, and abnormal histological features of skeletal muscle. Additionally, spatially resolved gene expression of muscle cross sections were altered in AAV8-P301L myofibers. Transcriptional changes showed alterations of genes encoding sarcomeric proteins, proposing a weakness phenotype. Strikingly, specific force of the soleus muscle was blunted in AAV8-P301L tau male mice. Our findings suggest tauopathy has peripheral consequences in skeletal muscle that contribute to weakness in tauopathy.

Swimming alters some proteins of skeletal muscle tissue in rats with Alzheimer-like phenotype

OBJECTIVES

Exercise training plays a significant role in preventing the destruction of central nerve neurons and muscle atrophy. The purpose of the present study was to investigate the effect of a period of swimming training on the expression of Neural cell adhesion molecule (NCAM), Semaphorin 3A (SEMA3A), and Profilin-1 (PFN1) proteins in the gastrocnemius muscle of Alzheimer-like phenotype rats.

METHODS & MATERIALS

32 Wistar males were (6 weeks of age) divided into four groups: Healthy Control (HC), Alzheimer-like phenotype's Control (AC), Healthy Training (HT), and Alzheimer-like phenotype's Training (AT). Alzheimer-like phenotypes were induced by beta-amyloid injection in the hippocampus. The training program consisted of 20 swimming sessions. Gastrocnemius muscle was removed after the intervention, and NCAM, SEMA3A, and PFN1 proteins were measured by the immunohistoflorescent method.

RESULTS

The results showed that SEMA3A was increased (p = 0.001), and NCAM (p = 0.001), and PFN1 (p = 0.001) were decreased in AC compared to the HC group. Also, the results showed that NCAM (p = 0.001) and Pfn1 (p = 0.002) increased in the HT group compared to HC, and the NCAM (p = 0.001) and Pfn1 (p = 0.002) in AT group compared to AC (p = 0.001) increased significantly, while SEMA3A was reduced in the HT group compared to HC (p = 0.001) and AT group compared to AC (p = 0.001) CONCLUSION: Swimming effectively improves axon regeneration and neuronal formation in motor neurons and, therefore, can be an effective intervention to prevent and control the complications of Alzheimer-like phenotype.

Using magnetic resonance imaging to measure head muscles: An innovative method to opportunistically determine muscle mass and detect sarcopenia

BACKGROUND

Sarcopenia is associated with multiple adverse outcomes. Traditional methods to determine low muscle mass for the diagnosis of sarcopenia are mainly based on dual-energy X-ray absorptiometry (DXA), whole-body magnetic resonance imaging (MRI) and bioelectrical impedance analysis. These tests are not always available and are rather time consuming and expensive. However, many brain and head diseases require a head MRI. In this study, we aim to provide a more accessible way to detect sarcopenia by comparing the traditional method of DXA lean mass estimation versus the tongue and masseter muscle mass assessed in a standard brain MRI.

METHODS

The H70 study is a longitudinal study of older people living in Gothenburg, Sweden. In this cross-sectional analysis, from 1203 participants aged 70 years at baseline, we included 495 with clinical data and MRI images available. We used the appendicular lean soft tissue index (ALSTI) in DXA images as our reference measure of lean mass. Images from the masseter and tongue were analysed and segmented using 3D Slicer. For the statistical analysis, the Spearman correlation coefficient was used, and concordance was estimated with the Kappa coefficient.

RESULTS

The final sample consisted of 495 participants, of which 52.3% were females. We found a significant correlation coefficient between both tongue (0.26) and masseter (0.33) with ALSTI (P < 0.001). The sarcopenia prevalence confirmed using the alternative muscle measure in MRI was calculated using the ALSTI (tongue = 2.0%, masseter = 2.2%, ALSTI = 2.4%). Concordance between sarcopenia with masseter and tongue versus sarcopenia with ALSTI as reference has a Kappa of 0.989 (P < 0.001) for masseter and a Kappa of 1 for the tongue muscle (P < 0.001). Comorbidities evaluated with the Cumulative Illness Rating Scale were significantly associated with all the muscle measurements: ALSTI (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.07-1.26, P < 0.001), masseter (OR 1.16, 95% CI 1.07-1.26, P < 0.001) and tongue (OR 1.13, 95% CI 1.04-1.22, P = 0.002); the higher the comorbidities, the higher the probability of having abnormal muscle mass.

CONCLUSIONS

ALSTI was significantly correlated with tongue and masseter muscle mass. When performing the sarcopenia diagnostic algorithm, the prevalence of sarcopenia calculated with head muscles did not differ from sarcopenia calculated using DXA, and almost all participants were correctly classified using both methods.

Novel insights into brain lipid metabolism in Alzheimer's disease: Oligodendrocytes and white matter abnormalities

Alzheimer's disease (AD) is the most common cause of dementia. A genome-wide association study has shown that several AD risk genes are involved in lipid metabolism. Additionally, epidemiological studies have indicated that the levels of several lipid species are altered in the AD brain. Therefore, lipid metabolism is likely changed in the AD brain, and these alterations might be associated with an exacerbation of AD pathology. Oligodendrocytes are glial cells that produce the myelin sheath, which is a lipid-rich insulator. Dysfunctions of the myelin sheath have been linked to white matter abnormalities observed in the AD brain. Here, we review the lipid composition and metabolism in the brain and myelin and the association between lipidic alterations and AD pathology. We also present the abnormalities in oligodendrocyte lineage cells and white matter observed in AD. Additionally, we discuss metabolic disorders, including obesity, as AD risk factors and the effects of obesity and dietary intake of lipids on the brain.

Effects of remote combine exercise-music training on physical and cognitive performance in patients with Alzheimer's disease: a randomized controlled trial

Introduction

This study aimed to investigate the effects of combined remote music and exercise training on the cognitive, psychological, and physical function of patients with Alzheimer's disease (AD).

Methods

Forty-one AD patients were randomly allocated to three groups, including control (C), training (T), and training with music (TM) groups. Participants were evaluated by cognitive and performance test batteries before and after the interventions. Both experimental groups performed 36 remote workouts in 3 months online via WhatsApp video call individually with the trainer. Training included simple and varied movements of all physical indicators. The number of sets began with two sets and progressively increased to one set every month, 5-10 repetitions per set. The overload was applied by reducing the break between sets every week. The TM group performed the same exercises while listening to Mozart and traditional Iranian songs.

Results

We observed a significant main, group, time, and interaction effect on Romberg (ηp2:0.72), 30 s chair sit and stand (ηp2:0.75), and walking on steppe test (ηp2:0.63). Furthermore, there was a significant main time and interaction effect on push-ups (ηp2:0.43), sit and reach (ηp2:0.64), and MMSE (ηp2:0.76). In all variables, two experimental groups demonstrated substantial improvements than the C group (p < 0.01). In addition, the TM group (27.8%) showed a significant improvement compared to the C group (-6.4%) and the T group (12.2%) in MMSE.

Conclusion

Combined remote training with listening to music as adjuvant treatment is an appropriate item to improve the cognitive and physical performance of Alzheimer's patients, especially during the COVID-19 pandemic.

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.

Validation of SARC-F-Proxy for the Screening of Sarcopenia in Older Patients with Cognitive Impairment

Objectives

The SARC-F is a validated questionnaire for the screening of sarcopenia in an older population. However, the clinical relevance of this self-reported questionnaire in patients with cognitive problems is questionable. This study aims to validate the SARC-F-Proxy as an alternative screening tool for sarcopenia in patients with cognitive impairment.

Methods

This cross-sectional study included hospitalised community-dwelling older adults aged 60 years or older with confirmed cognitive impairment. Three SARC-F questionnaires were completed: one by patients, one by informal caregivers and one by formal caregivers. Muscle strength, mass and physical performance were measured by handgrip strength, anthropometric measurements, and gait speed respectively. The recently updated EWGSOP2 diagnostic criteria were used as the "gold standard" for diagnosis of sarcopenia.

Results

The prevalence of sarcopenia using SARC-F-Proxy was 75.4% for SARC-F-Proxy-Formal caregiver and 66% for SARC-F-Proxy-Informal caregiver. SARC-F-Proxy had high sensitivity (85.9% for SARC-F-Proxy-Formal caregiver and 77% for SARC-F-proxy-informal caregiver) and low specificity (46.5% for SARC-F-Proxy-Formal caregiver and 54.7% for SARC-F-Proxy-Informal caregiver).

Conclusions

the proxy-reported SARC-F questionnaire can be applied as a surrogate for the SARC-F in the screening of sarcopenia in hospitalised community-dwelling older people with known or suspected cognitive impairment. Second, the results in this study suggest a higher reliability when the proxy-reported questionnaire is performed by the formal caregiver.

Association between muscle strength and executive function in Tibetan adolescents at high altitude in China: Results from a cross-sectional study at 16-18 years of age

BACKGROUND

In recent years, adolescents have shown a trend of decreasing muscle strength, especially in the upper limbs, and it affects the development of executive functions. However, few studies have been conducted on Tibetan adolescents in high-altitude regions of China. To this end, this study investigated upper limb muscle strength and executive function in Tibetan adolescents in Tibetan regions of China and analyzed the association between them.

METHODS

A three-stage stratified whole-group sampling method was used to test and investigate grip strength, executive function, and basic information in 1093 Tibetan adolescents from Tibet, a high-altitude region of China. A chi-square test and one-way ANOVA were used to compare the basic status and executive function of Tibetan adolescents with different muscle strength. Multiple linear regression analysis and logistic regression analysis were used to analyze the correlations that existed between muscle strength and each sub-function of executive function.

RESULTS

The differences between the inconsistently and congruent reaction times of Tibetan adolescents with different grip strength levels (P75 ) at high altitude in China were statistically significant (F-values of 32.596 and 31.580, respectively; P-values <.001). The differences between the 1-back and 2-back response times for the refresh memory function were also statistically significant (F-values of 9.055 and 6.610, respectively; P-values <.01). Linear regression analysis showed that after adjusting for the relevant covariates, the 1-back reaction time of Tibetan adolescents in the grip strength < P25 group increased by 91.72 ms (P < .01); the 2-back reaction time of Tibetan adolescents in the grip strength < P25 group increased by 105.25 ms (P < 0.01), using grip strength > P75 as the reference group. Logistic regression analysis showed that, after adjusting for relevant covariates, Tibetan adolescents in the grip strength < P25 group had a higher risk of developing 2-back dysfunction (OR = 1.89, 95% CI: 1.24,2.88), using grip strength >P75 as the reference group (P < .01). The risk of cognitive flexibility dysfunction (OR = 1.86, 95% CI: 1.16, 2.98) was also increased (P < .05).

CONCLUSION

There was a significant correlation between grip strength and executive function of refresh memory function and cognitive flexibility in Tibetan adolescents in high altitude areas of China. Those with higher upper limb muscle strength had shorter reaction time, that is, better executive function. In the future, we should focus on improving the upper limb muscle strength of Tibetan adolescents at high altitude in China to better promote the development of executive function.

Targeted brain-specific tauopathy compromises peripheral skeletal muscle integrity and function

Tauopathies are neurodegenerative disorders in which the pathological intracellular aggregation of the protein tau causes cognitive deficits. Additionally, clinical studies report muscle weakness in populations with tauopathy. However, whether neuronal pathological tau species confer muscle weakness, and whether skeletal muscle maintains contractile capacity in primary tauopathy remains unknown. Here, we identified skeletal muscle abnormalities in a mouse model of primary tauopathy, expressing human mutant P301L-tau using adeno-associated virus serotype 8 (AAV8). AAV8-P301L mice showed grip strength deficits, hyperactivity, and abnormal histological features of skeletal muscle. Additionally, spatially resolved gene expression of muscle cross sections were altered in AAV8-P301L myofibers. Transcriptional changes showed alterations of genes encoding sarcomeric proteins, proposing a weakness phenotype. Strikingly, specific force of the soleus muscle was blunted in AAV8-P301L tau male mice. Our findings suggest tauopathy has peripheral consequences in skeletal muscle that contribute to weakness in tauopathy.

Creatine as a Therapeutic Target in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, affecting approximately 6.5 million older adults in the United States. Development of AD treatment has primarily centered on developing pharmaceuticals that target amyloid-β (Aβ) plaques in the brain, a hallmark pathological biomarker that precedes symptomatic AD. Though recent clinical trials of novel drugs that target Aβ have demonstrated promising preliminary data, these pharmaceuticals have a poor history of developing into AD treatments, leading to hypotheses that other therapeutic targets may be more suitable for AD prevention and treatment. Impaired brain energy metabolism is another pathological hallmark that precedes the onset of AD that may provide a target for intervention. The brain creatine (Cr) system plays a crucial role in maintaining bioenergetic flux and is disrupted in AD. Recent studies using AD mouse models have shown that supplementing with Cr improves brain bioenergetics, as well as AD biomarkers and cognition. Despite these promising findings, no human trials have investigated the potential benefits of Cr supplementation in AD. This narrative review discusses the link between Cr and AD and the potential for Cr supplementation as a treatment for AD.

Relationship between sarcopenic obesity and cognitive function in patients with mild to moderate Alzheimer's disease

BACKGROUND

Previous research has linked sarcopenic obesity (SO) to cognitive function; however, the relationship between cognitive performance and SO Alzheimer's disease (AD) patients remains unclear. This study aimed to investigate their relationship in AD patients.

METHODS

One hundred and twenty mild to moderate AD patients and 56 normal controls were recruited. According to sarcopenia or obesity status, AD patients were classified into subgroups: normal, obesity, sarcopenia, and SO. Body composition, demographics, and sarcopenia parameters were assessed. Cognitive performance was evaluated using neuropsychological scales.

RESULTS

Among the 176 participants, the prevalence of SO in the moderate AD group was higher than in the normal control group. The moderate AD group had the lowest appendicular skeletal muscle mass index (ASMI) and the highest percentage of body fat (PBF). Hypertension and diabetes were more prevalent in the SO group than in the normal group among the subgroups. The sarcopenia and SO groups exhibited worse global cognitive function compared to the normal and obesity groups. Partial correlation analysis revealed that ASMI, PBF, and visceral fat area were associated with multiple cognitive domains scores. In logistic regression analysis, after adjusting for confounders, obesity was not found to be associated with AD. However, sarcopenia (odds ratio (OR) = 5.35, 95% CI: 1.27-22.46) and SO (OR = 5.84, 95% CI: 1.26-27.11) were identified as independent risk factors for AD.

CONCLUSIONS

SO was associated with cognitive dysfunction in AD patients. Moreover, the impact of SO on cognitive decline was greater than that of sarcopenia. Early identification and intervention for SO may have a positive effect on the occurrence and progression of AD.

Effects of PROtein enriched MEDiterranean Diet and EXercise on nutritional status and cognition in adults at risk of undernutrition and cognitive decline: the PROMED-EX Randomised Controlled Trial

INTRODUCTION

Undernutrition leading to unplanned weight loss is common in older age and has been linked to increased dementia risk in later life. Weight loss can precede dementia by a decade or more, providing a unique opportunity for early intervention to correct undernutrition and potentially prevent or delay cognitive impairment. The combined effects of diet and exercise on undernutrition have not yet been evaluated. The objective of this trial is to determine the effect of a protein-enriched Mediterranean diet, with and without exercise, on nutritional status and cognitive performance in older adults at risk of undernutrition and cognitive decline.

METHODS

One hundred and five participants aged 60 years and over at risk of undernutrition and with subjective cognitive decline will be recruited to participate in a 6-month, single-blind, parallel-group randomised controlled trial. Participants will be block randomised into one of three groups: group 1-PROMED-EX (diet+exercise), group 2-PROMED (diet only) and group 3-standard care (control). The primary outcome is nutritional status measured using the Mini Nutritional Assessment. Secondary outcomes include cognitive function, nutritional intake, body composition, physical function and quality of life. Mechanistic pathways for potential diet and exercise-induced change in nutritional status and cognition will be explored by measuring inflammatory, metabolic, nutritional and metabolomic biomarkers.

ETHICS AND DISSEMINATION

The study is approved by the UK Office for Research Ethics Committee (ref: 21/NW/0215). Written informed consent will be obtained from participants prior to recruitment. Research results will be disseminated to the public via meetings and media and the scientific community through conference presentations and publication in academic journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT05166564).

Strength and multiple types of physical activity predict cognitive function independent of low muscle mass in NHANES 1999–2002

Introduction

Multiple domains of cognitive function decline with age, resulting in a significant burden on quality of life and the healthcare system. Recent studies increasingly point to links between muscle mass, particularly low muscle mass, and risk of cognitive decline. However, complex relationships exist between muscle mass, muscle function, physical activity, and overall health.

Methods

Data from 1,424 adults 60+ years old in the 1999‐2000 and 2001‐2002 editions of the National Health and Nutrition Examination Survey (NHANES) were used to investigate the relationship between low muscle mass and cognitive function after accounting for strength, physical activity, and nutritional and metabolic risk factors for cognitive decline.

Results

Muscle strength and physical activity independently predicted performance in the digit symbol substitution test, with muscle mass and muscle strength explaining 0.5% and 5% of the variance in cognitive function, respectively. In graphical network analyses, the association between low muscle mass and cognitive function appeared to be primarily mediated by neuromuscular function. Physical activity was associated with strength but, surprisingly, not muscle mass, which was instead more closely related to total mass.

Conclusions

Low muscle mass is a relatively poor predictor of cognitive function after accounting for physical activity and strength in older individuals from a representative population dataset in the US. Future studies should account for the way in which muscle mass is accrued, which is likely to confound any association between muscle mass and health outcomes.

Factors associated with Alzheimer's disease prevalence and mortality in Brazil-An ecological study

A few epidemiological studies are evaluating the prevalence and mortality rates of Alzheimer's disease, with no one using a nationwide sample of Brazilian elderlies. This study aims to calculate the prevalence of Alzheimer's disease and investigate possible associations with sociodemographic and lifestyle factors and the presence of diseases non-communicable, and the prevalence and mortality for all Brazilian state capitals. This is an ecological design study made with secondary public data provided by the Ministry of Health. Prevalence rates were calculated based on the analysis of the dispensing of Alzheimer's disease-specific drugs. Correlation analyzes were performed between rates and factors, and a multiple linear regression analysis was used to analyze possible associations between variables, controlled for each other. AD prevalence was 313/100,000. Prevalence rates were positively associated with primary health care coverage factors and negatively associated with ultra-processed food consumption and physical activity levels. AD mortality was 98/100,000. Mortality rates were positively associated with the proportion of obese elderly and elderly living on up to half the minimum wage and were inversely associated with the proportion of elderly with diabetes factors. We found positive and negative associations of sociodemographic, behavioral and diabetes indicators with Alzheimer's disease prevalence and mortality, which provide data that can be investigated by studies with different designs.

Reduced body cell mass and functions in lower extremities are associated with mild cognitive impairment and Alzheimer's dementia

This study examined the alterations of segmental body composition in individuals with Alzheimer's pathology (AD), including mild cognitive impairment (MCI) and dementia. A multifrequency bioimpedance analysis (BIA) was used to provide segmental water and impedance variables from 365 cognitively normal (CN), 123 MCI due to AD, and 30 AD dementia participants. We compared the BIA variables between the three groups, examined their correlations with neuropsychological screening test scores, and illustrate their 95% confidence RXc graphs. AD dementia participants were older, more depressive, and had worse cognitive abilities than MCI due to AD and CN participants. Although the BIA variables showed weak partial correlations with the cognitive test scores, we found patterns of an increasing water content in lean mass, increasing extra to intracellular water ratio, and decreasing reactance and phase angle in the lower extremities with effect sizes ranging from 0.26 to 0.51 in the groups of MCI and dementia due to AD compared with CN individuals. The RXc graphs upheld the findings with a significant displacement downward and toward the right, dominantly in the lower extremities. Individuals with AD pathology exhibit a reduced body cell mass or cell strength, an abnormal cellular water distribution, and an overhydration status in lean mass, especially in the lower extremities.

Several dementia subtypes and mild cognitive impairment share brain reduction of neurotransmitter precursor amino acids, impaired energy metabolism, and lipid hyperoxidation

Objective

Dementias and mild cognitive impairment (MCI) are associated with variously combined changes in the neurotransmitter system and signaling, from neurotransmitter synthesis to synaptic binding. The study tested the hypothesis that different dementia subtypes and MCI may share similar reductions of brain availability in amino acid precursors (AAPs) of neurotransmitter synthesis and concomitant similar impairment in energy production and increase of oxidative stress, i.e., two important metabolic alterations that impact neurotransmission.

Materials and methods

Sixty-five demented patients (Alzheimer's disease, AD, n = 44; frontotemporal disease, FTD, n = 13; vascular disease, VaD, n = 8), 10 subjects with MCI and 15 control subjects (CTRL) were recruited for this study. Cerebrospinal fluid (CSF) and plasma levels of AAPs, energy substrates (lactate, pyruvate), and an oxidative stress marker (malondialdehyde, MDA) were measured in all participants.

Results

Demented patients and subjects with MCI were similar for age, anthropometric parameters, biohumoral variables, insulin resistance (HOMA index model), and CSF neuropathology markers. Compared to age-matched CTRL, both demented patients and MCI subjects showed low CSF AAP tyrosine (precursor of dopamine and catecholamines), tryptophan (precursor of serotonin), methionine (precursor of acetylcholine) limited to AD and FTD, and phenylalanine (an essential amino acid largely used for protein synthesis) (p = 0.03 to <0.0001). No significant differences were found among dementia subtypes or between each dementia subtype and MCI subjects. In addition, demented patients and MCI subjects, compared to CTRL, had similar increases in CSF and plasma levels of pyruvate (CSF: p = 0.023 to <0.0001; plasma: p < 0.002 to <0.0001) and MDA (CSF: p < 0.035 to 0.002; plasma: p < 0.0001). Only in AD patients was the CSF level of lactate higher than in CTRL (p = 0.003). Lactate/pyruvate ratios were lower in all experimental groups than in CTRL.

Conclusion

AD, FTD, and VaD dementia patients and MCI subjects may share similar deficits in AAPs, partly in energy substrates, and similar increases in oxidative stress. These metabolic alterations may be due to AAP overconsumption following high brain protein turnover (leading to phenylalanine reductions), altered mitochondrial structure and function, and an excess of free radical production. All these metabolic alterations may have a negative impact on synaptic plasticity and activity.

Relationships Between Body Composition and Cognitive Impairment in Hospitalised Middle-Aged Type 2 Diabetic Patients

Objective

The aim of this study was to elucidate the relationship between specific body composition and the risk of Cognitive Impairment (CI) in middle-aged Type 2 Diabetes Mellitus (T2DM) patients.

Methods

This cross-sectional study included 504 hospitalized patients with T2DM from the Department of Endocrinology and Metabolism of the Tianjin Union Medical Center. Subjects were grouped by sex, and cognitive status was assessed using the Montreal Cognitive Assessment (MoCA). The relationship between body composition and cognitive ability was investigated with the use of linear regression analysis. The association between body composition and CI risk was determined by logistic regression analysis.

Results

The prevalence of CI was 39.3% in middle-aged T2DM patients. After adjusting for age, education, marriage status, carotid atherosclerosis, cerebrovascular disease and hemoglobin, multiple linear regression analysis showed that lean mass index (LMI), body mass index (BMI) and appendicular skeletal muscle index (SMI) were significant predictors for the MoCA scores in men (p < 0.05). In addition, BMI (OR 0.913, 95% CI 0.840-0.992) and LMI (OR 0.820, 95% CI 0.682-0.916) were independent protective factors for CI in males. After adjusted for age, education, marriage status, dietary control of diabetes and cerebrovascular disease, visceral obesity (VO, OR 1.950, 95% CI 1.033-3.684) and abdominal obesity (AO, OR 2.537, 95% CI 1.191-5.403) were risk factors for CI in female patients.

Conclusion

The results suggest that there may be different mechanisms underlying the relationship of body compositions and cognitive performance between middle-aged male and female patients with T2DM. In addition, our finding of potential determinants of cognitive impairment may facilitate the development of intervention programs for middle-aged type 2 diabetic patients. Nevertheless, more large prospective studies looking at cognition and changes in body composition over time are needed in the future to further support their association.

Positive association between weight-adjusted-waist index and dementia in the Chinese population with hypertension: a cross-sectional study

PURPOSE

The links between obesity and dementia remain equivocal. Therefore, this study aimed to explore the association between weight-adjusted waist index (WWI), a new anthropometric indicator reflecting obesity, and dementia in the Chinese population with hypertension.

METHODS

A total of 10,289 participants with hypertension were enrolled in this cross-sectional study, a subset of the China H-type hypertension registry study. WWI was calculated as waist circumference (WC) divided by the square root of bodyweight. Mini-mental state examination (MMSE) scale was performed to evaluate the cognitive function. According to educational background, different MMSE cut-off values were applied to define dementia: < 24 for participants with ≥ 7 years of education, < 20 for those with 1-6 years of education, and < 17 for illiterate participants. Multivariable linear regression and multivariable binary logistic regression analyses were conducted to assess the associations between WWI and MMSE and dementia, respectively.

RESULTS

Overall, the mean age was 63.7 ± 9.7 years, and 49.0% were males. Multivariate linear regression analyses showed that WWI was negatively associated with MMSE (β, -1.09; 95% confidence interval [CI]: -1.24, -0.94). Consistently, multivariable binary logistic regression analyses found a positive association between WWI and the risk of dementia (odds ratio [OR], 1.45; 95% CI: 1.35, 1.56). Compared with individuals in quartile 1 of WWI, the adjusted β and OR values of WWI for MMSE and dementia were -2.28 (95% CI: -2.62, -1.94) and 2.12 (95% CI: 1.81, 2.48), respectively. Results of smoothing curve fitting confirmed the linear association between WWI and MMSE and dementia. Subgroup analysis showed a stronger association between WWI and dementia in participants with hypertension with midday napping.

CONCLUSION

WWI was independently and positively associated with dementia among the population with hypertension, especially in those with midday napping. The data suggests that WWI may serve as a simple and effective tool for the assessment of the risk of dementia in clinical practice.