Sarcopenia and Cognitive Decline in Older Adults: Targeting the Muscle-Brain Axis

"Mind-Muscle Connections": Differential Associations Between Handgrip and Upper Body Strength With Cognitive Function in Young and Middle-Aged Adults

The relationship between muscle strength and cognition is widely studied in older adults; however, understanding this association at younger ages may help detect markers of early cognitive changes and inform future interventions. Accordingly, we aimed to identify relationships between handgrip, whole-body, upper body, and lower body strength and cognitive functions. A total of 112 adults (aged 18-50 years) completed comprehensive measures of muscle strength, aerobic capacity, body composition, and cognitive function. Hierarchical linear regressions revealed that individuals with stronger handgrip had better mental rotation performance (standardized β = 0.39); those with greater upper body strength had superior recognition (standardized β = 0.52) and pattern separation abilities (standardized β = 0.39), but whole- and lower body strength were not associated. Results demonstrate the unique relationship between upper body strength and aspects of cognitive function, in addition to differential associations of upper body and handgrip strength with encoding, retrieval, and spatial skills. The current findings establish an association between strength and cognitive function earlier than previously thought.

Streptococcus salivarius subsp. thermophilus ST-G30 Prevents Dexamethasone-Induced Muscle Atrophy in C2C12 Myotubes

Background/Objectives: Sarcopenia is characterized by loss of muscle mass and strength and is associated with aging. Recently, its links with the gut-muscle axis have been reported, suggesting that probiotics could influence muscle health. Methods: In the present study, we investigated the protective roles of two lactic acid bacteria strains, Streptococcus salivarius subsp. thermophilus ST-G30 (ST-G30) and Lacticaseibacillus paracasei LPc-G110 (LPc-G110), on skeletal muscle atrophy induced by dexamethasone (DEX) in C2C12 myotubes. Results: Our results demonstrated that ST-G30 significantly alleviated DEX-induced myotube atrophy by increasing the myotubes' diameter (25.95 ± 1.28 vs. 15.30 ± 0.30 μm, p < 0.01), improving the fusion index (48.35 ± 1.75 vs. 22.16 ± 2.36%, p < 0.0001), and increasing the protein content (1.78 ± 0.02 vs. 1.56 ± 0.01 mg/mL, p < 0.05) and myotube length (0.61 ± 0.05 vs. 0.33 ± 0.01, p < 0.05), whereas LPc-G110 showed no significant effect on these phenotypes (p > 0.05). Transcriptomic analysis reveals that ST-G30 modulates critical signaling pathways and biological processes related to skeletal muscle health. In the current study, KEGG enrichment analysis and WGCNA enabled identification of the PI3K-Akt signaling pathway as a key regulator of these processes, highlighting its essential role in mitigating DEX-induced muscle atrophy. Furthermore, the overlapping DEGs associated with the PI3K-Akt signaling pathway showed strong correlations with muscle atrophy-related indices. Conclusions: These findings underscore the potential of ST-G30 as a promising anti-muscle atrophy supplement and provide valuable insights for developing strategies to prevent and treat glucocorticoid-induced skeletal muscle atrophy.

Determinants of dementia risk among older adults with probable sarcopenia and sarcopenia

BACKGROUND

Probable sarcopenia is a condition related to low muscle strength which increases the risk of sarcopenia. Both probable sarcopenia and sarcopenia increases the risk of dementia. The aim of this study is to investigate the factors associated with dementia among probable sarcopenia and sarcopenia older adults. It was hypothesized that comorbidities among probable sarcopenia and sarcopenia subjects may elevate the risk of dementia.

METHODOLOGY

This study involved 194 older adults with probable sarcopenia and sarcopenia aged 60 years and above. Sarcopenia was assessed using the Asian Working Group of Sarcopenia (AWGS) 2019. Among the parameters investigated in this study were sociodemographic, medical history, anthropometry, body composition, physical fitness, subjective cognitive decline, depressive symptoms, cognitive function and functional status. Dementia risk was assessed using the Montreal Cognitive Assessment (MoCA) tool. Adjusted binary logistic regression was employed to identify the factors associated with dementia among probable sarcopenia and sarcopenia older adults.

RESULTS

Probable sarcopenia subjects with dementia were older (68.5(7.8) years old) as compared to those without dementia (66.0(6.0) years old). Among the probable sarcopenia, 66.1% of the subjects with dementia had hypertension, while 64.3% of the sarcopenia subjects had hypertension. Fat mass was significantly higher among dementia subjects with probable sarcopenia (33.0(6.5) %) as compared to non-dementia subjects (30.4(6.8) %). Multivariate analysis revealed that hypertension (OR: 4.049; 95% CI: 1.510; 10.855, p = 0.005) was the only factor associated with dementia risk among older adults with probable sarcopenia and sarcopenia.

CONCLUSION

Hypertension is the only factors associated with risk of dementia after adjusting for potential confounders among older adults with probable sarcopenia and sarcopenia. Good control of blood pressure is essential among sarcopenia patients for lowering risk of dementia. Well-designed clinical trials are essential to investigate optimizing blood pressure level to reduce risk of dementia among patients with sarcopenia and probable sarcopenia.

Cognitive frailty: A comprehensive clinical paradigm beyond cognitive decline

Cognitive frailty is an emerging concept in research and clinical practice that incorporates both physical frailty and mild cognitive impairment (MCI) or subjective cognitive decline (SCD). Unlike traditional approaches that separate physical frailty and dementia, cognitive frailty treats these domains as interrelated and coexisting, with significant implications for clinical outcomes and predicting cognitive decline. Despite growing recognition of this interrelationship, a dualistic view of physical and cognitive processes persists. The paradigm of cognitive frailty holds promise as a biomarker- like amyloid plaques or neurofibrillary tangles- but with the advantage of identifying risk at a prefrail stage, before clinical signs of MCI or dementia emerge. This review examines the pathophysiological and clinical dimensions of cognitive frailty and promotes for its integration into routine assessments in memory clinics.

Rethinking Depression-Beyond Neurotransmitters: An Integrated Psychoneuroendocrineimmunology Framework for Depression's Pathophysiology and Tailored Treatment

It is known that the effectiveness of drug treatment for depression, ammine deficit based, is largely unsatisfactory. In this review, we examine the proposal of a precision therapy has emerged and has received a strong push by the identification of the role of inflammation in depression. However, precision psychiatry risks being caught in the reductionist trap of searching for the molecular switch that resets the whole system and switches off the disease. This is an illusion since the human being is complex and depression is a systemic and variable disorder. In this study, we show the inadequacy of the reductionist paradigm, and, at the same time, illustrate the superiority of the systemic paradigm centered on psychoneuroendocrineimmunology (PNEI). According to the PNEI paradigm, depression is a disease of the whole human being, caused by different sources working together: psychological, biological, and behavioral. This means knowing the biological and psychological history of the subject, identifying relational and biological crisis factors, and building personalized treatments targeting those factors with the tools of medicine and psychology, which are not reducible to the combination of drugs and psychotherapy. Our proposal presents a paradigm shift that is both theoretical and practical, which enables clinicians to assess patients experiencing depression in a unified way and treat them in an integrated manner.

Physical performance tests for preliminary cognitive screening in older adults: A systematic review of strength, walking, and balance assessments

OBJECTIVE

The aim of this systematic review is to determine which physical tests, particularly those assessing strength, walking abilities and balance stability, can provide the most pertinent information for a preliminary screening of cognitive status, facilitating further cognitive evaluation.

METHODS

A systematic search was conducted using the PubMed and Web of Science databases. Studies that assessed both strength or balance stability and cognitive state in community-dwelling adults aged ≥60 years old were selected for inclusion.

RESULTS

The search strategy identified a total of 864 studies. After removing duplicates and applying inclusion and exclusion criteria, ten studies comprising a total of 6868 subjects were included in the review. According to the GRADE system, the studies were classified as low quality. Cognitively healthy individuals exhibited better balance, higher strength levels, greater gait speed and higher instrumental activities of daily living scores compared to those with mild cognitive impairment or cognitive impairment.

CONCLUSION

The assessment of physical function in older adults may serve as a useful tool in identifying impairments associated with physical frailty, sarcopenia, and cognitive decline. Early screening based on physical performance could assist healthcare professionals in determining the need for further cognitive assessment, potentially aiding in the prevention or early detection of cognitive decline.

Risk of sarcopenia: A red flag for cognitive decline in postmenopause?

OBJECTIVE

To determine if the SARC-F tool, used to screen for sarcopenia risk, can also predict mild cognitive impairment (MCI) diagnosed with the Montreal Cognitive Assessment (MoCA) tool.

METHODS

This is a sub-analysis of data from a cross-sectional study carried out in postmenopausal women from Latin America (nine countries) in which sociodemographic, clinical, and anthropometric data were collected, and the SARC-F and MoCA tools administered. From the original sample of 1185 women, analysis was performed only among the 772 with natural menopause.

RESULTS

Overall, mean age, body mass index and years of education were 56.9 years, 26.8 kg/m2 and 13.6 years, respectively. Women with MCI displayed a higher body mass index, had more children, experienced more severe menopausal symptoms, and were more frequently homemakers and physically inactive. The prevalence of MCI increased from 12.9 % in women with no sarcopenia risk (SARC-F < 4 points) to 35.3 % in those at risk (OR 3.70; 95 % CI 2.36-5.80). According to binary logistic regression analysis, sarcopenia risk (total SARC-F score ≥ 4) was associated with MCI (OR: 2.44; 95 % CI 1.50-3.95). Aside from the risk of sarcopenia, being a homemaker (OR 1.97; 95 % CI 1.25-3.10) was also associated with an increased likelihood of MCI. Protective factors included ever use of menopausal hormone therapy (OR 0.26; 95 % CI 0.13-0.54) and having higher educational attainment (OR 0.28; 95 % CI 95 % 0.16-0.47). The SARC-F displayed a sensitivity of 84 % and a specificity of 39 % at diagnosing MCI.

CONCLUSION

This study suggests that the SARC-F questionnaire, used to assess sarcopenia risk, could also predict the presence of MCI in postmenopausal women. There is a need for more research to support our preliminary findings.

Potential common targets of music therapy intervention in neuropsychiatric disorders: the prefrontal cortex-hippocampus -amygdala circuit (a review)

As life becomes more stressful, neurological disorders, psychiatric disorders, and comorbidities of the two are becoming more and more of a concern. Multiple neuropsychiatric disorders share the same mental and somatic dysfunction and may involve common brain circuits and mechanistic targets. Music therapy, as an art form with proven efficacy, low cost and few side effects, is promoted for use in interventions for neuropsychiatric disorders. This may be closely related to the release of signaling molecules such as monoamine neurotransmitters, the glutamatergic system, the gut-microbiota-brain axis, pro-inflammatory cytokines and the endogenous opioid peptide system. However, fewer studies have mentioned the main targets of music to promote functional changes in brain regions. Therefore, this paper is a review of the mechanisms by which music therapy interacts with the prefrontal cortex-hippocampus-amygdala circuit through the aforementioned molecules. It is also hypothesized that glial cells, mitochondria and microRNAs are microscopic targets for musical intervention in neuropsychiatric disorders. The aim is to give new ideas for future research into the biological mechanisms of music therapy intervention in neuropsychiatric disorders.

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.

Assessment and management of frailty in individuals living with dementia: expert recommendations for clinical practice

Frailty complicates the care of individuals with dementia, increasing their vulnerability to adverse outcomes. This Personal View presents expert recommendations for managing frailty in individuals with dementia, aimed at health-care providers, particularly those in primary care. We conducted a rapid literature review followed by a consensus process involving 18 international experts on dementia and frailty. The experts identified key areas, including diagnosis of frailty, assessment of nutritional status and nutritional management, physical activity, prevention of falls, and polypharmacy management. The recommendations emphasise early identification of frailty and a comprehensive, interdisciplinary approach to care that aims to maintain the individual's daily functioning, quality of life, and independence. The recommendations highlight the importance of tailored interventions, regular monitoring, and the integration of psychosocial support into the therapeutic approach. These recommendations address a crucial gap in existing clinical guidelines, offering practical guidance for clinicians managing frailty in individuals with dementia.

Exploring the mediating role of depression in the relationship between sarcopenia and cardiovascular health in the middle-aged and elderly: A cross-sectional study

BACKGROUND

Cardiovascular health is influenced by various factors, including sarcopenia and depression. It has been demonstrated that sarcopenia has a negative impact on cardiovascular disease, with depression also being a contributing factor. However, the complex interplay between sarcopenia, depressive symptoms, and cardiovascular health in middle-aged and elderly populations is not fully explored.

METHODS

A total of 23,445 participants participated in China Health and Retirement Longitudinal Study and completed relevant measurements, including the Centre for Epidemiological Studies Depression Scale. The study also assessed sarcopenia and cardiovascular health score. The focus of the study was to test whether the association between sarcopenia and cardiovascular health scores was mediated by depression using PROCESS macros in R 4.3.2. Sensitivity analyses were conducted to affirm the robustness of our findings.

RESULT

The study revealed a partial mediation between sarcopenia and cardiovascular health score among the middle and elder adults, mediated by depression. Sarcopenia had a significant negative correlation with cardiovascular health score (B = -12.404, P < 0.05), and depression also showed a significant negative correlation (B = -1.515, P < 0.001).

CONCLUSION

The results support the notion that depression partially mediated the association between sarcopenia and cardiovascular health score. Therefore, interventions aimed at improving mood and addressing other cardiovascular risk factors may help alleviate the adverse effects of sarcopenia and potentially reduce the progression to cardiovascular disease.

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.

Blood RNA transcripts show changes in inflammation and lipid metabolism in Alzheimer's disease and mitochondrial function in mild cognitive impairment

Background

Abnormal immunity in the periphery has been reported in the pathogenesis of Alzheimer's disease (AD).

Objective

In this study, blood transcriptome analyses of patients with AD, those with mild cognitive impairment (MCI) due to AD, and heathy controls were performed to elucidate immune-related pathophysiology.

Methods

The sample included 63 participants from a complete enumeration study of elderly people in Nakayama town (the Nakayama Study), who were over 65 years of age, diagnosed as (1) healthy controls (N = 21, mean age: 83.8 years), (2) having MCI due to AD (N = 20, mean age: 82.6 years), or (3) having AD (N = 21, mean age: 84.2 years). Every participant underwent blood tests, magnetic resonance imaging, and questionnaires about lifestyle and cognitive function. With transcriptome analysis, differential gene expressions in the blood of the three groups were evaluated by gene ontology, pathway enrichment, and ingenuity pathway analyses, and quantitative real-time PCR was performed.

Results

Neutrophil extracellular trap signaling was increased, and lipid metabolism (FXR/RXR activation, triacylglycerol degradation) was decreased in AD, whereas MCI showed protective responses via decreased neutrophil extracellular trap signaling and mitochondrial functions such as upregulation of the sirtuin pathway and downregulation of oxidative stress.

Conclusions

Based on these findings and consistent with other published studies, immune cells appear to have important roles in the pathogenesis of AD, and the transcriptome in blood may be useful as a biomarker for diagnosis via monitoring immunity in MCI and AD.

Causality of genetically determined glucosamine supplementation on cognition and sarcopenia: a Mendelian randomization study

BACKGROUND

Evidence indicates a negative link between glucosamine and age-related cognitive decline and sarcopenia. However, the causal relationship remains uncertain. This study aims to verify whether glucosamine is causally associated with cognitive function and sarcopenia.

METHOD

Forty-eight genetic variants linked to glucosamine use were extracted from the MRC-IEU consortium. Besides, we gathered cognition proxy indicators [cognitive performance and fluid intelligence score (FIS)], and sarcopenia-related indicators, namely, appendicular lean mass (ALM), whole body fat-free mass (WBFM), low hand grip strength, facial aging (FA), moderate to vigorous physical activity levels, usual walking pace and DNA methylation GrimAge acceleration from the large publicly available genome-wide association studies. Initially, Mendelian randomization (MR) analyses were conducted to ascertain the causal impact of glucosamine on cognition and sarcopenia-related traits. Subsequently, the two-step MR and multivariable MR (MVMR) were employed to examine whether any mediators causally mediated the observed associations.

RESULT

MR analysis indicated that glucosamine was associated with increased cognitive performance (p = 8.46E-04), FIS (p = 7.50E-04), ALM (p = 6.45E-08), WBFM (p = 1.97E-03), usual walking pace (p = 2.55E-07), and moderate to vigorous physical activity levels (p = 3.29E-03), but associated with decreased FA risk (p = 3.77E-05) and DNA methylation GrimAge acceleration (p = 0.001). However, there were no significant causal associations between glucosamine and low hand grip strength. Multivariable MR showed that glucosamine continued to have a significant effect on cognitive performance, FIS, ALM, WBFM, usual walking pace, and moderate to vigorous physical activity levels after controlling for osteoarthritis (OA) and body mass index (BMI) (p < 0.05). We further found that C-reactive protein levels (CRP) may mediate the association of glucosamine and ALM, WBFM, usual walking pace, and physical activity (p < 0.05), and basal metabolic rate (BMR) may mediate the association of glucosamine and cognitive performance, FIS, ALM, WBFM, and usual walking pace (p < 0.05).

CONCLUSION

Regular glucosamine use enhances cognitive function and postpones sarcopenia for preserving the functional capacities necessary, and the impact of glucosamine on cognition and sarcopenia could be partially attributed to the mediation of BMR and CRP.

The mitochondrial function of peripheral blood cells in cognitive frailty patients

Background

Cognitive frailty (CF), characterized by the coexistence of physical frailty and cognitive impairment, is linked to increased morbidity and mortality in older adults. While CF has been linked to multiple physiological and lifestyle factors, the underlying biological mechanisms remain poorly understood. This study investigated the risk factors for CF and explored the relationship between mitochondrial function and CF in hospitalized patients.

Methods

A total of 279 hospitalized individuals were recruited from December 2020 to August 2022, conducted comprehensive clinical assessments, and collected peripheral blood samples. CF was evaluated using the Physical Frailty Phenotype and Montreal Cognitive Assessment scales. Nutritional status was assessed with the Mini Nutritional Assessment, and depression was measured using the Geriatric Depression Scale. DNA was obtained from the peripheral blood and interrogated for mitochondrial DNA copy number (mtDNAcn). Peripheral blood mononuclear cells isolated from peripheral blood were examined for respiratory function and reactive oxygen species (ROS) levels. Additionally, plasma samples were analyzed for inflammatory markers and Carnitine Palmitoyltransferase II (CPT2).

Results

Among the participants, 90 were classified as CF and 46 as non-CF. Logistic regression analysis revealed that increased age (OR 1.156, 95% CI 1.064-1.255), lower educational attainment (OR 0.115, 95% CI 0.024-0.550), malnutrition (OR 0.713, 95% CI 0.522-0.973), and higher depression scores (OR 1.345, 95% CI 1.065-1.699) were significantly associated with CF. The independent t tests and Mann-Whitney U tests showed the CF group exhibited impaired mitochondrial function, characterized by reduced mtDNAcn and respiratory activity, coupled with elevated ROS, interleukin-6, and CPT2 levels compared with the non-CF group. After adjusted for age, sex, and BMI, compared with non-CF group, the OR values for the CF group of mtDNAcn and ROS were 0.234 (95% CI = 0.065-0.849) (p = 0.027) and 1.203 (95% CI = 1.075-1.347) (p = 0.001), respectively. The Sensitive analysis showed that the area under curve values for mtDNAcn and ROS were 0.653 and 0.925.

Conclusion

Age, lower educational attainment, malnutrition, and depression are significant risk factors for CF. Moreover, mitochondrial dysfunction, characterized by decreased mtDNAcn, impaired respiratory function and increased ROS levels appears to be a critical phenotype of CF.

Association of sarcopenia, ambient air pollution and cognitive function in a community-dwelling middle-aged and elderly Korean population: a community-based cohort study

OBJECTIVES

To investigate the association of sarcopenia, exposure to medium-term to long-term ambient particulate matter 2.5 µm and 10 µm (PM2.5 and PM10) pollution and cognitive function in a community-dwelling cohort of middle-aged and older adults in South Korea.

DESIGN

A community-based prospective cohort study.

SETTING

In the Korean Genome and Epidemiology Study (KoGES).

PARTICIPANTS

The participants were drawn from the seventh follow-up visit conducted between 2015 and 2016 in the KoGES community-based Ansung cohort who had participated in an ageing substudy.

OUTCOME MEASURES

Cognitive function was evaluated by the Korean version of the Mini-Mental State Examination (K-MMSE) and decreased cognitive function was defined as a K-MMSE score of 23 or less.

RESULTS

Of the 2274 participants (mean age 70.1 years, 58.3% women and mean annual PM2.5 and PM10 levels of 30.7 and 52.2 μg/m3, respectively), 8.7% (n=197) were sarcopenic, 35.8% (n=814) were possible sarcopenic and 55.5% (n=1263) were non-sarcopenic. The predictors of sarcopenia included body mass index, cognitive function, age, marital status, hypertension and physical activity. Exposure to PM2.5 and PM10 for an average duration of 1 month to 3 years was not selected as a predictor of sarcopenia. Participants with sarcopenia were associated with lower cognitive scores (β=-1.51, p<0.0001) and decreased cognitive function compared with those without sarcopenia (OR 2.34, 95% CI 1.56 to 3.52). Exposure to medium-term and long-term PM2.5 or PM10 was not associated with sarcopenia. The effect modification of PM exposure on the association between sarcopenia and cognitive function was generally not detected.

CONCLUSIONS

In this community-based observational cohort study of KoGES participants aged 50 years and older, sarcopenia was associated with decreased cognitive function. However, medium-term to long-term exposure to PM2.5 or PM10 was not associated with sarcopenia and did not modify the relationship between sarcopenia and cognitive function.

Muscular strength, endothelial function and cognitive disorders: state of the art

In recent years, the ageing population has increasingly grown. This process carries a range of pathophysiological changes involving alterations in the skeletal muscle, vascular endothelium and brain function, becoming an important risk factor for developing cognitive disorders and cardiovascular diseases. With ageing, there is a decrease in muscle mass and muscle strength, and a relationship between muscle strength decrease and cognitive decline has been shown. Lower handgrip strength has been linked to memory impairment, lower global cognitive function, decreased attention and reduced visuospatial abilities in the elderly, but understanding of the underlying mechanisms that explain the link between altered skeletal muscle function and structure, endothelial dysfunction, and the role of endothelial dysfunction in the onset of cognitive disorders has been scarcely explored. This review aims to detail the cellular and molecular mechanisms by which the progressive changes associated with ageing can alter healthy skeletal muscle and endothelial function, creating an environment of oxidative stress, inflammation and mitochondrial dysfunction. These changes can lead to reduced muscle strength, and the secretion of detrimental endothelial factors, resulting in endothelial dysfunction, blood-brain barrier disruption, and damage to neurons and microglia, ultimately accelerating the onset of cognitive disorders in the elderly. In addition, we aimed to describe the mechanisms that potentially explain how preserving muscular function with resistance training could prevent brain function deterioration, including the production of different factors that allow an improved endothelial function, haemodynamic parameters and brain plasticity, ultimately delaying the onset of cognitive impairment and chronic diseases.

A study of the correlation between sarcopenia and cognitive impairment in older individuals over 60 years: cross-sectional and longitudinal validation

Objective

To validate the correlation between sarcopenia and cognition, and explore cognitive subdomains affected by sarcopenia.

Methods

A case-control study was designed to recruit 90 individuals aged 60 and above from June to October 2023 in the same community, all individuals meeting the inclusion criteria were categorized according to the 2019 Asian criteria for sarcopenia and divided into the sarcopenia group and non-sarcopenia group at baseline. After a 12-week follow-up recording, individuals were classified into the aggravation group and alleviation group based on the change of sarcopenia severity. Sarcopenia tests including muscle mass, calf circumference, grip strength and physical function assessment, using Montreal Cognitive Assessment (MoCA) of nine dimensions for cognitive assessment.

Results

(1) There was a significant positive correlation between cognitive function and grip strength in males (r = 0.42, p < 0.05). (2) There was a moderate correlation between sarcopenia grading and MoCA score (r = -0.4, p < 0.001). (3) Individuals with sarcopenia had significantly lower MoCA total scores and sub-scores in executive function, fluency, calculation and delayed recall compared to non-sarcopenia group (p < 0.05). (4) After 12 weeks, the mean value of the change in fluency in the alleviation group increased by 0.33 points, while the aggravation group decreased by 0.2 points (W = 128, p < 0.05).

Conclusion

There is a correlation between sarcopenia and cognitive function, individuals with sarcopenia performing poorly in overall cognition as well as refined dimensions. The degree of cognition like fluency degenerates over time with increasing severity of sarcopenia.

Redefining Roles: A Paradigm Shift in Tryptophan-Kynurenine Metabolism for Innovative Clinical Applications

The tryptophan-kynurenine (KYN) pathway has long been recognized for its essential role in generating metabolites that influence various physiological processes. Traditionally, these metabolites have been categorized into distinct, often opposing groups, such as pro-oxidant versus antioxidant, excitotoxic/neurotoxic versus neuroprotective. This dichotomous framework has shaped much of the research on conditions like neurodegenerative and neuropsychiatric disorders, as well as cancer, where metabolic imbalances are a key feature. The effects are significantly influenced by various factors, including the concentration of metabolites and the particular cellular milieu in which they are generated. A molecule that acts as neuroprotective at low concentrations may exhibit neurotoxic effects at elevated levels. The oxidative equilibrium of the surrounding environment can alter the function of KYN from an antioxidant to a pro-oxidant. This narrative review offers a comprehensive examination and analysis of the contemporary understanding of KYN metabolites, emphasizing their multifaceted biological functions and their relevance in numerous physiological and pathological processes. This underscores the pressing necessity for a paradigm shift in the comprehension of KYN metabolism. Understanding the context-dependent roles of KYN metabolites is vital for novel therapies in conditions like Alzheimer's disease, multiple sclerosis, and cancer. Comprehensive pathway modulation, including balancing inflammatory signals and enzyme regulation, offers promising avenues for targeted, effective treatments.

Osteosarcopenia predicts greater risk of functional disability than sarcopenia: a longitudinal analysis of FraDySMex cohort study

OBJECTIVES

Aging involves significant changes in body composition, marked by declines in muscle mass and bone mineral density alongside an increase in fat mass. Sarcopenia is characterized by low strength and muscle mass, and osteosarcopenia is the coexistence of sarcopenia and osteopenia/osteoporosis. Physiologically, there is a crosstalk between muscle and bone tissues mediated by several pathways. Both, sarcopenia and osteosarcopenia, have been related with adverse outcomes such as functional disability. However, there is a lack of longitudinal studies. Therefore, this study aimed to assess whether sarcopenia and osteosarcopenia phenotypes increased the risk of functional disability in a longitudinal cohort of community-dwelling adults.

DESIGN

This study constitutes a secondary longitudinal analysis of data derived from the prospective cohort FraDySMex (Frailty, Dynapenia, and Sarcopenia in Mexican adults).

SETTING AND PARTICIPANTS

FraDySMex is conducted in community-dwelling adults aged 50 years or older living in Mexico City. Data from 2014 to 2015 was considered as baseline evaluation, and the 2019 wave was the follow-up evaluation. Individuals with complete baseline and follow-up evaluations were included in the analysis.

MEASUREMENTS

Sarcopenia diagnosis adhered to the FNIH criteria, while osteopenia/osteoporosis classification followed WHO guidelines. Osteosarcopenia was defined as the concurrent presence of sarcopenia and osteopenia/osteoporosis. Functional disability was identified by the Lawton Instrumental Activities of Daily Living (IADL) Scale. Adjusted mixed-effects logistic regression models were estimated to evaluate the effect of body composition phenotype on the risk of functional disability.

RESULTS

The final sample included 320 adults with complete longitudinal data. The majority of were women (83.4%) and had 7-12 years of education (48.4%). At the baseline evaluation, 50.9% aged 50-70. The osteosarcopenia phenotype was associated with a higher risk of functional disability (OR: 2.17, p = 0.042) compared with the no osteopenia/sarcopenia group. Conversely, sarcopenia (OR: 1.50, p = 0.448) and osteopenia/osteoporosis (OR: 1.50, p = 0.185) phenotypes were not associated with functional disability.

CONCLUSIONS

Our study underscores that osteosarcopenia significantly increased the risk of functional disability, particularly in terms of Instrumental Activities of Daily Living (IADL). These results emphasize the importance of screening for sarcopenia, osteopenia/osteoporosis, and osteosarcopenia across various clinical settings. Early detection and intervention hold promise for averting functional disability and mitigating associated adverse outcomes in adults.

Understanding exogenous factors and biological mechanisms for cognitive frailty: A multidisciplinary scoping review

Cognitive frailty (CF) is the conjunction of cognitive impairment without dementia and physical frailty. While predictors of each element are well-researched, mechanisms of their co-occurrence have not been integrated, particularly in terms of relationships between social, psychological, and biological factors. This interdisciplinary scoping review set out to categorise a heterogenous multidisciplinary literature to identify potential pathways and mechanisms of CF, and research gaps. Studies were included if they used the definition of CF OR focused on conjunction of cognitive impairment and frailty (by any measure), AND excluded studies on specific disease populations, interventions, epidemiology or prediction of mortality. Searches used Web of Science, PubMed and Science Direct. Search terms included "cognitive frailty" OR (("cognitive decline" OR "cognitive impairment") AND (frail*)), with terms to elicit mechanisms, predictors, causes, pathways and risk factors. To ensure inclusion of animal and cell models, keywords such as "behavioural" or "cognitive decline" or "senescence", were added. 206 papers were included. Descriptive analysis provided high-level categorisation of determinants from social and environmental through psychological to biological. Patterns distinguishing CF from Alzheimer's disease were identified and social and psychological moderators and mediators of underlying biological and physiological changes and of trajectories of CF development were suggested as foci for further research.

Effects of Creatine Monohydrate Supplementation on Muscle, Bone and Brain- Hope or Hype for Older Adults?

PURPOSE OF REVIEW

Sarcopenia, generally characterized by the age-related reduction in muscle strength, lean/muscle mass and functional ability, is also associated with reduced bone mass and strength and impaired brain health and function. One potential intervention which has received much 'hype' over the past few decades to countermeasure these negative consequences of biological aging is creatine monohydrate supplementation.

RECENT FINDINGS

From a skeletal muscle perspective, the combination of creatine monohydrate supplementation and resistance training provides 'hope' for older adults as it improves measures of lean mass, regional (limb) muscle thickness, upper- and lower-body muscle strength and functional ability. Further, there is some evidence that creatine (supplementation or habitual diet) provides a ray of 'hope' for improving some aspects of cognitive function. The majority of research suggests that creatine is more 'hype' than 'hope' for improving measures of bone mass in older adults. Creatine monohydrate supplementation provides some anti-sarcopenic benefits for older adults.

Skeletal muscle reprogramming enhances reinnervation after peripheral nerve injury

Peripheral Nerve Injuries (PNI) affect more than 20 million Americans and severely impact quality of life by causing long-term disability. PNI is characterized by nerve degeneration distal to the site of nerve injury resulting in long periods of skeletal muscle denervation. During this period, muscle fibers atrophy and frequently become incapable of "accepting" innervation because of the slow speed of axon regeneration post injury. We hypothesize that reprogramming the skeletal muscle to an embryonic-like state may preserve its reinnervation capability following PNI. To this end, we generate a mouse model in which NANOG, a pluripotency-associated transcription factor is expressed locally upon delivery of doxycycline (Dox) in a polymeric vehicle. NANOG expression in the muscle upregulates the percentage of Pax7+ nuclei and expression of eMYHC along with other genes that are involved in muscle development. In a sciatic nerve transection model, NANOG expression leads to upregulation of key genes associated with myogenesis, neurogenesis and neuromuscular junction (NMJ) formation. Further, NANOG mice demonstrate extensive overlap between synaptic vesicles and NMJ acetylcholine receptors (AChRs) indicating restored innervation. Indeed, NANOG mice show greater improvement in motor function as compared to wild-type (WT) animals, as evidenced by improved toe-spread reflex, EMG responses and isometric force production. In conclusion, we demonstrate that reprogramming muscle can be an effective strategy to improve reinnervation and functional outcomes after PNI.

Educational attainment, brain cortical structure, and sarcopenia: a Mendelian randomization study

Background

Previous observational studies have suggested associations between high-level educational attainment (EA) and a lower risk of sarcopenia. However, the causality inferred from those studies was subjected to residual confounding and reverse causation. The protective effect of EA on sarcopenia may be mediated via changes in brain cortical structure. The aim of this study was to use a two-step Mendelian randomization (MR) analysis to illustrate the causal relationship between EA, brain cortical structure, and sarcopenia.

Methods

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. We perform several sensitivity analyses, including Cochran Q test, MR-Egger intercept test, leave-one-out analyses, and MR Pleiotropy Residual Sum and Outlier to evaluate the reliability of the results.

Results

EA was causally associated with increased appendicular lean mass (β = 0.25, 95% confidence interval (CI): 0.19 to 0.31, p = 2.25 × 10-15), hand grip strength (left: β = 0.042, 95% CI: 0.013 to 0.071, p = 4.77 × 10-3 and right: β = 0.050, 95% CI: 0.022 to 0.079, p = 5.17 × 10-4), and usual walking pace (β = 0.20, 95% CI: 0.18 to 0.22, p = 6.16 × 10-83). In addition, EA was associated with increased brain cortical surface area (β = 4082.36, 95% CI: 2513.35 to 5681.38, p = 3.40 × 10-7) and cortical thickness (TH) (β = 0.014, 95% CI: 0.0045 to 0.023, p = 3.45 × 10-3). Regarding the causal effect of EA on usual walking pace, the mediatory effect of TH was 0.0069 and the proportion of mediation by TH was 3.43%.

Conclusion

The study will have revealed the protective causal effect of EA on sarcopenia, which provides a reference for the prevention of sarcopenia at the public health level. We also will have found EA could affect the brain cortical structure, and the brain cortical structure could mediate the protective effect of EA against sarcopenia risk.

Advancements in sarcopenia diagnosis: from imaging techniques to non-radiation assessments

Sarcopenia is a prevalent condition with significant clinical implications, and it is expected to escalate globally, demanding for effective diagnostic strategies, possibly at an early stage of the disease. Imaging techniques play a pivotal role in comprehensively evaluating sarcopenia, offering insights into both muscle quantity and quality. Among all the imaging techniques currently used for the diagnosis and follow up of sarcopenia, it is possible to distinguish two classes: Rx based techniques, using ionizing radiations, and non-invasive techniques, which are based on the use of safe and low risk diagnostic procedures. Dual-energy x-ray Absorptiometry and Computed Tomography, while widely utilized, entail radiation exposure concerns. Ultrasound imaging offers portability, real-time imaging, and absence of ionizing radiation, making it a promising tool Magnetic Resonance Imaging, particularly T1-weighted and Dixon sequences, provides cross- sectional and high-resolution images and fat-water separation capabilities, facilitating precise sarcopenia quantification. Bioelectrical Impedance Analysis (BIA), a non-invasive technique, estimates body composition, including muscle mass, albeit influenced by hydration status. Standardized protocols, such as those proposed by the Sarcopenia through Ultrasound (SARCUS) Working Group, are imperative for ensuring consistency across assessments. Future research should focus on refining these techniques and harnessing the potential of radiomics and artificial intelligence to enhance diagnostic accuracy and prognostic capabilities in sarcopenia.

Integrative insights into PNI: Low-grade chronic inflammation, skeletal muscle wasting, and brain impairments

Skeletal muscle has been recognized as an endocrine organ which communicates with different systems, including the brain. In conditions involving systemic low-grade chronic inflammation , the skeletal muscle can be negatively impacted, culminating in its quantity (mass) and quality (function) losses, referred to here as muscle wasting. The inflammatory milieu, as well known, also impairs the brain function, however there are some particularities involving skeletal muscle-brain crosstalk, including cognitive function and mental health impairments . Psychoneuroimmunology (PNI) is an important field of neuroendocrine-immune-behavior science and an approach between PNI, and the movement science, or kinesiology, field can enrich future research about the relationship between skeletal muscle wasting and brain health. Thus, in this short review, we present an overview about the interplay between skeletal muscle, inflammatory mediator markers, and brain function with the purpose to strengthen the ties between kinesiology and PNI research to enhance futures discoveries and advances in health sciences.

The relationship between cognitive frailty, physical frailty and malnutrition in Turkish older adults

OBJECTIVE

The aim of this study was to assess the relationship between cognitive and physical frailty and malnutrition in older adults.

METHODS

The study was cross-sectional and observational. A total of 992 patients who applied to the geriatric outpatient clinic between January 2018 and December 2022 were included in the study. All patients underwent comprehensive geriatric assessment. Demographic characteristics, geriatric syndromes, comorbidities, and laboratory parameters were recorded. Fried's Frailty Scale was used to determine physical frailty. The Mini Nutritional Assessment Short Form was performed to determine nutritional status. Cognitive frailty was defined as the coexistence of physical frailty and mild cognitive impairment.

RESULTS

Of 992 patients participating in the study, 66% were female, and the mean age was 73.2 ± 7.4. The rate of physical frailty was 13.4%, and 96 patients were cognitively frail. Malnutrition rates were 18.8%, 12.5%, and 2.2% in the cognitive frailty, physical frailty, and healthy control groups, respectively. The healthy control group had a lower median age, fewer geriatric syndromes (excluding orthostatic hypotension), and lower rates of diabetes and hypertension than the frailty groups. The frequency of malnutrition was similar in the cognitive and physical frailty groups. The cognitive frailty group had higher median age, sarcopenia rate, and Timed Up and Go duration; were less likely to be female; and showed lower albumin, mobility, and functionality scores than the physical frailty group (P < 0.05). After adjusting for demographic characteristics, comorbidities, geriatric syndromes, and laboratory parameters, cognitive frailty showed a stronger relationship with malnutrition (odds ratio 1.96, confidence interval 1.13-5.04, P = 0.04).

CONCLUSIONS

Cognitive and physical frailty were found to be associated with malnutrition in older adults. Even after accounting for confounding factors, it appears that cognitive frailty is more closely related to nutritional status than physical frailty.

The brain-body energy conservation model of aging

Aging involves seemingly paradoxical changes in energy metabolism. Molecular damage accumulation increases cellular energy expenditure, yet whole-body energy expenditure remains stable or decreases with age. We resolve this apparent contradiction by positioning the brain as the mediator and broker in the organismal energy economy. As somatic tissues accumulate damage over time, costly intracellular stress responses are activated, causing aging or senescent cells to secrete cytokines that convey increased cellular energy demand (hypermetabolism) to the brain. To conserve energy in the face of a shrinking energy budget, the brain deploys energy conservation responses, which suppress low-priority processes, producing fatigue, physical inactivity, blunted sensory capacities, immune alterations and endocrine 'deficits'. We term this cascade the brain-body energy conservation (BEC) model of aging. The BEC outlines (1) the energetic cost of cellular aging, (2) how brain perception of senescence-associated hypermetabolism may drive the phenotypic manifestations of aging and (3) energetic principles underlying the modifiability of aging trajectories by stressors and geroscience interventions.

Comprehensive analysis of molecular, physiological, and functional biomarkers of aging with neurological diseases using Mendelian randomization

An increasing burden of neurological diseases (NDs) has been a public health challenge in an aging society. Age, especially biological age, is the most important risk factor for NDs. Identification of biomarkers of aging to capture NDs might lead to a better understanding of the underlying mechanisms of pathological brain aging and the implementation of effective intervention. We conducted a comprehensive two-sample Mendelian Randomization (MR) study to investigate the association between various biomarkers of aging and three leading causes of NDs: Alzheimer's disease (AD), vascular dementia (VaD), and ischemic stroke. Publicly available GWAS summary statistics on people from European ancestry were obtained for six molecular biomarkers, two physiological biomarkers, and eight functional biomarkers, and three NDs. Genetic variants serving as instrumental variables (IVs) were identified for each biomarker. The MR analysis included inverse variance weighted (IVW), weighted median, MR-Egger, and MR-PRESSO. We found that short telomere length and decrease in appendicular lean mass were associated with an increased risk for AD (OR IVW = 1.12 per 1SD decrease, 95% confidence interval 1.02-1.22, and OR IVW = 1.11, 1.06-1.16, respectively), whereas high frailty index showed a protective effect for AD. Accelerated BioAge appeared to be associated with increased risk for ischemic stroke (OR IVW = 1.3 per year in BioAge acceleration, 95% CI 1.19-1.41). Our findings implied a causal association of short telomere length and a decrease in appendicular lean mass with an increased risk for AD, while BioAge appeared to be a good biomarker for ischemic stroke. Further studies are needed to validate these associations and explore underlying mechanisms.

Vascular Impairment, Muscle Atrophy, and Cognitive Decline: Critical Age-Related Conditions

The triad of vascular impairment, muscle atrophy, and cognitive decline represents critical age-related conditions that significantly impact health. Vascular impairment disrupts blood flow, precipitating the muscle mass reduction seen in sarcopenia and the decline in neuronal function characteristic of neurodegeneration. Our limited understanding of the intricate relationships within this triad hinders accurate diagnosis and effective treatment strategies. This review analyzes the interrelated mechanisms that contribute to these conditions, with a specific focus on oxidative stress, chronic inflammation, and impaired nutrient delivery. The aim is to understand the common pathways involved and to suggest comprehensive therapeutic approaches. Vascular dysfunctions hinder the circulation of blood and the transportation of nutrients, resulting in sarcopenia characterized by muscle atrophy and weakness. Vascular dysfunction and sarcopenia have a negative impact on physical function and quality of life. Neurodegenerative diseases exhibit comparable pathophysiological mechanisms that affect cognitive and motor functions. Preventive and therapeutic approaches encompass lifestyle adjustments, addressing oxidative stress, inflammation, and integrated therapies that focus on improving vascular and muscular well-being. Better understanding of these links can refine therapeutic strategies and yield better patient outcomes. This study emphasizes the complex interplay between vascular dysfunction, muscle degeneration, and cognitive decline, highlighting the necessity for multidisciplinary treatment approaches. Advances in this domain promise improved diagnostic accuracy, more effective therapeutic options, and enhanced preventive measures, all contributing to a higher quality of life for the elderly population.

From Brain to Muscle: The Role of Muscle Tissue in Neurodegenerative Disorders

Neurodegenerative diseases (NDs), like amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and Parkinson's disease (PD), primarily affect the central nervous system, leading to progressive neuronal loss and motor and cognitive dysfunction. However, recent studies have revealed that muscle tissue also plays a significant role in these diseases. ALS is characterized by severe muscle wasting as a result of motor neuron degeneration, as well as alterations in gene expression, protein aggregation, and oxidative stress. Muscle atrophy and mitochondrial dysfunction are also observed in AD, which may exacerbate cognitive decline due to systemic metabolic dysregulation. PD patients exhibit muscle fiber atrophy, altered muscle composition, and α-synuclein aggregation within muscle cells, contributing to motor symptoms and disease progression. Systemic inflammation and impaired protein degradation pathways are common among these disorders, highlighting muscle tissue as a key player in disease progression. Understanding these muscle-related changes offers potential therapeutic avenues, such as targeting mitochondrial function, reducing inflammation, and promoting muscle regeneration with exercise and pharmacological interventions. This review emphasizes the importance of considering an integrative approach to neurodegenerative disease research, considering both central and peripheral pathological mechanisms, in order to develop more effective treatments and improve patient outcomes.

Sleep duration and leisure activities are involved in regulating the association of depressive symptoms, muscle strength, physical function and mild cognitive impairment

Background

In order to lessen the burden of Alzheimer's disease (AD), timely and efficient management and intervention methods for mild cognitive impairment (MCI) are crucial. MCI is seen as a transitional stage between normal aging and dementia. Although sarcopenia is an important risk factor for MCI, it is unclear what factors mediates and regulates the brain-muscle communication. Our objective was to investigate the indirect moderating effects of sleep duration and leisure activity on depressive symptoms, sarcopenia and MCI.

Method

Panel data from the 2015 China Health and Retirement Longitudinal Study (CHARLS) database was used in this investigation. we used Bootstrap sampling to determine the relationship between sleep duration, leisure activity, depressive symptoms, sarcopenia, and MCI in mediation and indirect moderation models. The outcome measurements were odds ratio (OR) and confidence interval (CI).

Result

After adjusting for confounding variables, we discovered that sarcopenia and its traits, such as handgrip strength, gait speed, standing test, and muscle mass, were significantly correlated with MCI. Second, the results implied that depressive symptoms played a role in modulating the link between physical function, muscle strength, and MCI. This moderating effect was impacted by short sleep duration and moderate to high levels of leisure activities.

Conclusion

We discovered that MCI was highly correlated not only with physical function and muscle strength but also with depressed symptoms, which acted as a partially mediating factor in this connection. Handgrip strength, gait speed, and standing test mediated the correction of MCI caused by depression symptoms. Importantly, leisure activities and sleep duration had indirect moderating effects on the above associations, and future management policies should take these factors into account.

Development of a prediction model for cognitive impairment of sarcopenia using multimodal neuroimaging in non-demented older adults

INTRODUCTION

Despite prior research on the association between sarcopenia and cognitive impairment in the elderly, a comprehensive model that integrates various brain pathologies is still lacking.

METHODS

We used data from 528 non-demented older adults with or without sarcopenia in the Catholic Aging Brain Imaging (CABI) database, containing magnetic resonance imaging scans, positron emission tomography scans, and clinical data. We also measured three key components of sarcopenia: skeletal muscle index (SMI), hand grip strength (HGS), and the five times sit-to-stand test (5STS).

RESULTS

All components of sarcopenia were significantly correlated with global cognitive function, but cortical thickness and amyloid-beta (Aβ) retention had distinctive relationships with each measure. In the path model, brain atrophy resulting in cognitive impairment was mediated by Aβ retention for SMI and periventricular white matter hyperintensity for HGS, but directly affected by the 5STS.

DISCUSSION

Treatments targeting each sub-domain of sarcopenia should be considered to prevent cognitive decline.

HIGHLIGHTS

We identified distinct impacts of three sarcopenia measures on brain structure and Aβ. Muscle mass is mainly associated with Aβ and has an influence on the brain atrophy. Muscle strength linked with periventricular WMH and brain atrophy. Muscle function associated with cortical thinning in specific brain regions. Interventions on sarcopenia may be important to ease cognitive decline in the elderly.

Effects of Cognitive-Motor and Motor-Motor Dual Tasks on Gait Performance in Older Adults with Sarcopenia

BACKGROUND

With the advent of global aging, the health of the older population has become a critical public health challenge. The purpose of this study was to investigate the effect of dual-tasking on gait performance in patients with sarcopenia.

METHODS

Thirty participants with sarcopenia (age: 70.73 ± 4.12 yr, MMSE score: 26.90 ± 3.00), including 14 males and 16 females, were selected according to the diagnostic criteria of the Asian Working Group on Sarcopenia. All participants were instructed to perform the gait test in three modes: single task (ST), cognitive-motor dual task (CMDT), and motor-motor dual task (MMDT). Statistical analyses were performed using one-way ANOVA to evaluate the effects of different task types on gait parameters of the participants.

RESULTS

(1) Compared with ST walking, gait frequency, step length, and step speed decreased, and the gait cycle and double-support phase increased in patients with sarcopenia during dual-task walking (p < 0.05); (2) Compared with ST walking, gait variability indices such as stride frequency, stride length, and support period significantly increased in patients with sarcopenia during dual-task walking (p < 0.05).

CONCLUSIONS

The increased difficulty in postural control caused by dual-task interference may reduce the safety of motor strategies in patients with sarcopenia and increase the risk of falls. Future studies should focus on the effects of exercise interventions on multitasking patterns in people with sarcopenia to promote balance function in these populations.

Mild cognitive impairment predicts the onset of Sarcopenia: a longitudinal analysis from the English Longitudinal Study on Ageing

BACKGROUND

Mild cognitive impairment (MCI) and sarcopenia are two common conditions in older people. It is not widely known if MCI could predict the onset of sarcopenia. Therefore, we aimed to investigate whether MCI could predict the occurrence of sarcopenia in a population of older adults.

METHODS

In the ELSA (English Longitudinal Study on Ageing), MCI was defined as the absence of dementia, preserved functional capacity and low performance in three objective cognitive tests. Sarcopenia was diagnosed as having low handgrip strength and low skeletal muscle mass index during follow-up. The longitudinal association between MCI at the baseline and incident sarcopenia was assessed using a multivariable logistic regression model, reporting the data as adjusted odds ratios (OR) and 95% confidence intervals (95%CI).

RESULTS

3,106 participants (mean age of 63.1 years; 55.3% males) were included. People with MCI reported significantly lower mean handgrip strength values and Skeletal Mass Index (SMI), as well as a higher prevalence of obesity at baseline. At baseline, 729 people had MCI and during the ten years follow-up period, 12.1% of the initial population included had sarcopenia. On multivariate analysis, adjusted for 18 potential confounders, the presence of MCI (OR = 1.236; 95%CI: 1.090-1.596, p = 0.01) significantly predicted the onset of sarcopenia during follow-up.

CONCLUSION

The presence of MCI at baseline was associated with a higher incidence of sarcopenia at ten-years follow-up, demonstrating a likely role of MCI as a predictor of the onset of sarcopenia in older people.

SuperAgers and centenarians, dynamics of healthy ageing with cognitive resilience

Graceful healthy ageing and extended longevity is the most desired goal for human race. The process of ageing is inevitable and has a profound impact on the gradual deterioration of our physiology and health since it triggers the onset of many chronic conditions like dementia, osteoporosis, diabetes, arthritis, cancer, and cardiovascular disease. However, some people who lived/live more than 100 years called 'Centenarians" and how do they achieve their extended lifespans are not completely understood. Studying these unknown factors of longevity is important not only to establish a longer human lifespan but also to manage and treat people with shortened lifespans suffering from age-related morbidities. Furthermore, older adults who maintain strong cognitive function are referred to as "SuperAgers" and may be resistant to risk factors linked to cognitive decline. Investigating the mechanisms underlying their cognitive resilience may contribute to the development of therapeutic strategies that support the preservation of cognitive function as people age. The key to a long, physically, and cognitively healthy life has been a mystery to scientists for ages. Developments in the medical sciences helps us to a better understanding of human physiological function and greater access to medical care has led us to an increase in life expectancy. Moreover, inheriting favorable genetic traits and adopting a healthy lifestyle play pivotal roles in promoting longer and healthier lives. Engaging in regular physical activity, maintaining a balanced diet, and avoiding harmful habits such as smoking contribute to overall well-being. The synergy between positive lifestyle choices, access to education, socio-economic factors, environmental determinants and genetic supremacy enhances the potential for a longer and healthier life. Our article aims to examine the factors associated with healthy ageing, particularly focusing on cognitive health in centenarians. We will also be discussing different aspects of ageing including genomic instability, metabolic burden, oxidative stress and inflammation, mitochondrial dysfunction, cellular senescence, immunosenescence, and sarcopenia.

Cognition as mediator of pulmonary function and risk of sarcopenia among older adults

BACKGROUND

The relationship between lung function and sarcopenia remains ambiguous. The primary aim of this study was to investigate the potential association between lung function and sarcopenia in the older adults, as well as to examine the mediating role of cognitive function in this relationship.

METHODS

The participants were selected from a nationally representative population-based cohort in China. The peak expiratory flow (PEF) measurement was used to evaluate the lung function in older persons. The sarcopenia was diagnosed using the guidelines of the Asian Working Group for Sarcopenia (AWGS) in 2019. The Cox proportional hazard model was utilized to perform primary analyses of the relationship between PEF and sarcopenia. The mediating effect of cognitive function was evaluated using the counterfactual mediation method.

RESULTS

This cohort study included 4,011 older adults (average age, 66.6 years; 53.3% males). During a follow-up period of 3.86 years, 349 individuals were diagnosed with sarcopenia. After adjusting for potential confounders, each one-standard-deviation increase in PEF was associated with a 28% reduction in the risk of sarcopenia (hazard ratio [HR]: 0.72; 95% confidence interval [CI]: 0.63, 0.80). There was a significant mediation of cognition for the association between PEF and incident sarcopenia, and the proportion mediated was 12.2% (95% CI: 4.5%, 23.1%).

CONCLUSIONS

Older adults with impaired lung function are more likely to develop sarcopenia. Nevertheless, cognition can explain only a small portion of this association. Thus, other potential pathways between lung function and sarcopenia must be elucidated.

Association of low muscle mass with cognitive function and mortality in USA seniors: results from NHANES 1999-2002

BACKGROUND

Sarcopenia and cognitive impairment have been linked in prior research, and both are linked to an increased risk of mortality in the general population. Muscle mass is a key factor in the diagnosis of sarcopenia. The relationship between low muscle mass and cognitive function in the aged population, and their combined impact on the risk of death in older adults, is currently unknown. This study aimed to explore the correlation between low muscle mass and cognitive function in the older population, and the relationship between the two and mortality in older people.

METHODS

Data were from the National Health and Nutrition Examination Survey 1999-2002. A total of 2540 older adults aged 60 and older with body composition measures were included. Specifically, 17-21 years of follow-up were conducted on every participant. Low muscle mass was defined using the Foundation for the National Institute of Health and the Asian Working Group for Sarcopenia definitions: appendicular lean mass (ALM) (< 19.75 kg for males; <15.02 kg for females); or ALM divided by body mass index (BMI) (ALM: BMI, < 0.789 for males; <0.512 for females); or appendicular skeletal muscle mass index (ASMI) (< 7.0 kg/m2 for males; <5.4 kg/m2 for females). Cognitive functioning was assessed by the Digit Symbol Substitution Test (DSST). The follow-up period was calculated from the NHANES interview date to the date of death or censoring (December 31, 2019).

RESULTS

We identified 2540 subjects. The mean age was 70.43 years (43.3% male). Age-related declines in DSST scores were observed. People with low muscle mass showed lower DSST scores than people with normal muscle mass across all age groups, especially in the group with low muscle mass characterized by ALM: BMI (60-69 years: p < 0.001; 70-79 years: p < 0.001; 80 + years: p = 0.009). Low muscle mass was significantly associated with lower DSST scores after adjusting for covariates (ALM: 43.56 ± 18.36 vs. 47.56 ± 17.44, p < 0.001; ALM: BMI: 39.88 ± 17.51 vs. 47.70 ± 17.51, p < 0.001; ASMI: 41.07 ± 17.89 vs. 47.42 ± 17.55, p < 0.001). At a mean long-term follow-up of 157.8 months, those with low muscle mass were associated with higher all-cause mortality (ALM: OR 1.460, 95% CI 1.456-1.463; ALM: BMI: OR 1.452, 95% CI 1.448-1.457); ASMI: OR 3.075, 95% CI 3.063-3.088). In the ALM: BMI and ASMI-defined low muscle mass groups, participants with low muscle mass and lower DSST scores were more likely to incur all-cause mortality ( ALM: BMI: OR 0.972, 95% CI 0.972-0.972; ASMI: OR 0.957, 95% CI 0.956-0.957).

CONCLUSIONS

Low muscle mass and cognitive function impairment are significantly correlated in the older population. Additionally, low muscle mass and low DSST score, alone or in combination, could be risk factors for mortality in older adults.

Risk factors and a nomogram for predicting cognitive frailty in Chinese patients with lung cancer receiving drug therapy: A single-center cross-sectional study

BACKGROUND

To identify independent factors of cognitive frailty (CF) and construct a nomogram to predict cognitive frailty risk in patients with lung cancer receiving drug therapy.

METHODS

In this cross-sectional study, patients with lung cancer undergoing drug therapy from October 2022 to July 2023 were enrolled. The data collected includes general demographic characteristics, clinical data characteristics and assessment of tools for cognitive frailty and other factors. Logistic regression was harnessed to determine the influencing factors, R software was used to establish a nomogram model to predict the risk of cognitive frailty. The enhanced bootstrap method was employed for internal verification of the model. The performance of the nomogram was evaluated by using calibration curves, the area under the receiver operating characteristic curve, and decision curve analysis.

RESULTS

A total of 372 patients were recruited, with a cognitive frailty prevalence of 56.2%. Age, education background, diabetes mellitus, insomnia, sarcopenia, and nutrition status were identified as independent factors. Then, a nomogram model was constructed and patients were classified into high- and low-risk groups with a cutoff value of 0.552. The internal validation results revealed good concordance, calibration and discrimination. The decision curve analysis presented prominent clinical utility.

CONCLUSIONS

The prevalence of cognitive frailty was higher in lung cancer patients receiving drug therapy. The nomogram could identify the risk of cognitive frailty intuitively and simply in patients with lung cancer, so as to provide references for early screening and intervention for cognitive frailty at the early phases of drug treatment.

Linking sarcopenia, brain structure and cognitive performance: a large-scale UK Biobank study

Sarcopenia refers to age-related loss of muscle mass and function and is related to impaired somatic and brain health, including cognitive decline and Alzheimer's disease. However, the relationships between sarcopenia, brain structure and cognition are poorly understood. Here, we investigate the associations between sarcopenic traits, brain structure and cognitive performance. We included 33 709 UK Biobank participants (54.2% female; age range 44-82 years) with structural and diffusion magnetic resonance imaging, thigh muscle fat infiltration (n = 30 561) from whole-body magnetic resonance imaging (muscle quality indicator) and general cognitive performance as indicated by the first principal component of a principal component analysis across multiple cognitive tests (n = 22 530). Of these, 1703 participants qualified for probable sarcopenia based on low handgrip strength, and we assigned the remaining 32 006 participants to the non-sarcopenia group. We used multiple linear regression to test how sarcopenic traits (probable sarcopenia versus non-sarcopenia and percentage of thigh muscle fat infiltration) relate to cognitive performance and brain structure (cortical thickness and area, white matter fractional anisotropy and deep and lower brain volumes). Next, we used structural equation modelling to test whether brain structure mediated the association between sarcopenic and cognitive traits. We adjusted all statistical analyses for confounders. We show that sarcopenic traits (probable sarcopenia versus non-sarcopenia and muscle fat infiltration) are significantly associated with lower cognitive performance and various brain magnetic resonance imaging measures. In probable sarcopenia, for the included brain regions, we observed widespread significant lower white matter fractional anisotropy (77.1% of tracts), predominantly lower regional brain volumes (61.3% of volumes) and thinner cortical thickness (37.9% of parcellations), with |r| effect sizes in (0.02, 0.06) and P-values in (0.0002, 4.2e-29). In contrast, we observed significant associations between higher muscle fat infiltration and widespread thinner cortical thickness (76.5% of parcellations), lower white matter fractional anisotropy (62.5% of tracts) and predominantly lower brain volumes (35.5% of volumes), with |r| effect sizes in (0.02, 0.07) and P-values in (0.0002, 1.9e-31). The regions showing the most significant effect sizes across the cortex, white matter and volumes were of the sensorimotor system. Structural equation modelling analysis revealed that sensorimotor brain regions mediate the link between sarcopenic and cognitive traits [probable sarcopenia: P-values in (0.0001, 1.0e-11); muscle fat infiltration: P-values in (7.7e-05, 1.7e-12)]. Our findings show significant associations between sarcopenic traits, brain structure and cognitive performance in a middle-aged and older adult population. Mediation analyses suggest that regional brain structure mediates the association between sarcopenic and cognitive traits, with potential implications for dementia development and prevention.

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.

Prevalence and factors associated with sarcopenia among older adults in a post-acute hospital in Singapore

BACKGROUND

Sarcopenia is common in older adults worldwide, but its prevalence varies widely owing to differences in diagnostic criteria, population sampled, and care setting. We aimed to determine the prevalence and factors associated with sarcopenia in patients aged 65 and above admitted to a post-acute hospital in Singapore.

METHODS

This was a cross-sectional study of 400 patients recruited from a community hospital in Singapore. Data including socio-demographics, physical activity, nutritional status, cognition, clinical and functional status, as well as anthropometric measurements were collected. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 criteria [AWGS2019].

RESULTS

Of the 383 patients with complete datasets, overall prevalence of sarcopenia was 54% while prevalence of severe sarcopenia was 38.9%. Participants with increased age, male gender and a low physical activity level were more likely to be sarcopenic, while those with higher hip circumference and higher BMI of ≥27.5m/kg2 were less likely to be sarcopenic. Other than the above-mentioned variables, cognitive impairment was also associated with severe sarcopenia.

CONCLUSIONS

More than 1 in 2 older adults admitted to a post-acute hospital in Singapore are sarcopenic. There is an urgent need to address this important clinical syndrome burden and to identify patients at risk of sarcopenia in post-acute settings in Singapore for early intervention.

Skeletal muscle reprogramming enhances reinnervation after peripheral nerve injury

Peripheral Nerve Injuries (PNI) affect more than 20 million Americans and severely impact quality of life by causing long-term disability. The onset of PNI is characterized by nerve degeneration distal to the nerve injury resulting in long periods of skeletal muscle denervation. During this period, muscle fibers atrophy and frequently become incapable of "accepting" innervation because of the slow speed of axon regeneration post injury. We hypothesize that reprogramming the skeletal muscle to an embryonic-like state may preserve its reinnervation capability following PNI. To this end, we generated a mouse model in which NANOG, a pluripotency-associated transcription factor can be expressed locally upon delivery of doxycycline (Dox) in a polymeric vehicle. NANOG expression in the muscle upregulated the percentage of Pax7+ nuclei and expression of eMYHC along with other genes that are involved in muscle development. In a sciatic nerve transection model, NANOG expression led to upregulation of key genes associated with myogenesis, neurogenesis and neuromuscular junction (NMJ) formation, and downregulation of key muscle atrophy genes. Further, NANOG mice demonstrated extensive overlap between synaptic vesicles and NMJ acetylcholine receptors (AChRs) indicating restored innervation. Indeed, NANOG mice showed greater improvement in motor function as compared to wild-type (WT) animals, as evidenced by improved toe-spread reflex, EMG responses and isometric force production. In conclusion, we demonstrate that reprogramming the muscle can be an effective strategy to improve reinnervation and functional outcomes after PNI.

Current Perspectives: Obesity and Neurodegeneration - Links and Risks

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

From Chronodisruption to Sarcopenia: The Therapeutic Potential of Melatonin

Sarcopenia is an age-related condition that involves a progressive decline in muscle mass and function, leading to increased risk of falls, frailty, and mortality. Although the exact mechanisms are not fully understood, aging-related processes like inflammation, oxidative stress, reduced mitochondrial capacity, and cell apoptosis contribute to this decline. Disruption of the circadian system with age may initiate these pathways in skeletal muscle, preceding the onset of sarcopenia. At present, there is no pharmacological treatment for sarcopenia, only resistance exercise and proper nutrition may delay its onset. Melatonin, derived from tryptophan, emerges as an exceptional candidate for treating sarcopenia due to its chronobiotic, antioxidant, and anti-inflammatory properties. Its impact on mitochondria and organelle, where it is synthesized and crucial in aging skeletal muscle, further highlights its potential. In this review, we discuss the influence of clock genes in muscular aging, with special reference to peripheral clock genes in the skeletal muscle, as well as their relationship with melatonin, which is proposed as a potential therapy against sarcopenia.

Hallmarks of ageing in human skeletal muscle and implications for understanding the pathophysiology of sarcopenia in women and men

Ageing is a complex biological process associated with increased morbidity and mortality. Nine classic, interdependent hallmarks of ageing have been proposed involving genetic and biochemical pathways that collectively influence ageing trajectories and susceptibility to pathology in humans. Ageing skeletal muscle undergoes profound morphological and physiological changes associated with loss of strength, mass, and function, a condition known as sarcopenia. The aetiology of sarcopenia is complex and whilst research in this area is growing rapidly, there is a relative paucity of human studies, particularly in older women. Here, we evaluate how the nine classic hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication contribute to skeletal muscle ageing and the pathophysiology of sarcopenia. We also highlight five novel hallmarks of particular significance to skeletal muscle ageing: inflammation, neural dysfunction, extracellular matrix dysfunction, reduced vascular perfusion, and ionic dyshomeostasis, and discuss how the classic and novel hallmarks are interconnected. Their clinical relevance and translational potential are also considered.