Sarcopenia: Aging-Related Loss of Muscle Mass and Function

Study on the comorbid mechanisms of sarcopenia and late-life depression

The increasing global aging population has brought greater focus to age-related diseases, particularly muscle-brain comorbidities such as sarcopenia and late-life depression. Sarcopenia, defined by the gradual loss of muscle mass and function, is notably prevalent among older individuals, while late-life depression profoundly affects their mental health and overall well-being. Epidemiological evidence suggests a high co-occurrence of these two conditions, although the precise biological mechanisms linking them remain inadequately understood. This review synthesizes the existing body of literature on sarcopenia and late-life depression, examining their definitions, prevalence, clinical presentations, and available treatments. The goal is to clarify the potential connections between these comorbidities and offer a theoretical framework for the development of future preventive and therapeutic strategies.

Measurement of Twitch Dynamics in Response to Exercise Induced Changes in Mitochondrial Disease Using Motor Unit Magnetic Resonance Imaging (MUMRI): A Proof-of-Concept Study

Muscle twitch dynamics and fatigability change in response to muscle disease. In this study, we developed an imaging paradigm to measure muscle twitch dynamics, and the response of the muscle to voluntary fatiguing contractions. We used a novel imaging technique called motor unit magnetic resonance imaging (MUMRI). MUMRI allows visualisation of muscle and motor unit activity by combining in-scanner electrical stimulation with dynamic pulsed gradient spin echo (twitch dynamics, PGSE-MUMRI) and phase contrast (fatigue, PC-MUMRI) imaging. In Part I of this study, we scanned 10 healthy controls, we measured the muscle rise (Trise), contraction (Tcontract) and half-relaxation time (Thalf-relax) of the tibialis anterior (TA) muscle on a voxel-wise basis using PGSE-MUMRI. Five controls were scanned twice to assess reproducibility; PGSE-MUMRI demonstrated reproducible results, with low variation between scans 3.4% for Trise, 6.4% for Tcontract and 7.1% for Thalf-relax. We then developed a PC-MUMRI paradigm to measure the recovery of the TA in response to a fatiguing voluntary exercise. In Part II of the study, we applied these two novel imaging paradigms in a cohort study of nine patients with single large-scale mtDNA deletion primary mitochondrial myopathy (PMM). Patients underwent a 12-week resistance exercise programme and baseline, and follow-up MRI was performed. PGSE-MUMRI detected a significantly longer muscle contraction time between baseline and follow-up in PMM patients 108.7 ± 7.9 vs. post-119.3 ± 10.4 ms; p = 0.018. There was no statistical difference in the recovery half maximum measured using PC-MUMRI in PMM patients between baseline and follow-up 254 ± 109 vs. 137 ± 41 s; p = 0.074. In conclusion, PGSE-MUMRI has detected differences in muscle twitch dynamics between controls and PMM following an exercise programme, and we can visualise differences in twitch dynamics subregions of muscle using this technique. The PC-MUMRI technique has shown promise as a novel measure of muscle fatigue.

Latest developments of microphysiological systems (MPS) in aging-related and geriatric diseases research: A review

Aging is a gradual and irreversible process accompanied by the decline in tissue function and a significantly increased risk of various aging-related and geriatric diseases. Especially in the paradoxical context of accelerated global aging and the widespread emergence of pandemics, aging-related and geriatric diseases have become leading causes of individual mortality and disability, drawing increasing attention from researchers and investors alike. Despite the utility of current in vitro systems and in vivo animal models for studying aging, these approaches are limited by insurmountable inherent constraints. In response, microphysiological systems (MPS), leveraging advances in tissue engineering and microfluidics, have emerged as highly promising platforms. MPS are capable of replicating key features of the tissue microenvironment within microfabricated devices, offering biomimetic tissue culture conditions that enhance the in vitro simulation of intact or precise human body structure and function. This capability improves the predictability of clinical trial outcomes while reducing time and cost. In this review, we focus on recent advancements in MPS used to study age-related and geriatric diseases, with particular emphasis on the application of organoids and organ-on-a-chip technologies in understanding cardiovascular diseases, cerebrovascular diseases, neurodegenerative diseases, fibrotic diseases, locomotor and sensory degenerative disorders, and rare diseases. And we aim to provide readers with critical guidelines and an overview of examples for modeling age-related and geriatric diseases using MPS, exploring mechanisms, treatments, drug screening, and other subsequent applications, from a physiopathological perspective, emphasizing the characteristic of age-related and geriatric diseases and their established correlations with the aging process. We also discuss the limitations of current models and propose future directions for MPS in aging research, highlighting the potential of interdisciplinary approaches to address unresolved challenges in the field.

Expression patterns of blood-based biomarkers of neurodegeneration and inflammation across adulthood in rhesus macaques

As the global human population rapidly ages and diseases of aging become more prevalent, preclinical models of age-related neurodegenerative disorders are increasingly important for identifying early diagnostic biomarkers, monitoring disease progression, and evaluating treatment responsiveness. Rhesus macaques are an ideal species for studies on neurodegeneration due to their phylogenetic relatedness to humans and their complex brain anatomy and physiology. Technological advances in assay sensitivity have facilitated the identification of blood-based biomarkers of neurodegeneration and inflammation in human populations. The aim of this study was to translate these methods for use in male and female rhesus macaques across adulthood. We collected plasma samples from 47 rhesus macaques representing pre-adult (1-5 years, n = 6 female, n = 5 male), young (5-7 years, n = 5 female, n = 7 male), middle (8-16 years, n = 7 female, n = 7 male), and older adult (17-22 years, n = 6 female, n = 4 male) subjects. Quantified biomarkers included neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), amyloid beta (Aβ42, Aβ40, and their ratio), total tau, phosphorylated tau (pTau181), interleukin (IL) 2, IL-6, IL-8, and IL-10. Plasma NfL and IL-6 levels were significantly increased with age in both sexes, with a marked rise during middle adulthood. The ratio of Aβ42/Aβ40 was significantly lower in the middle and older aged females compared to the youngest group. There was no effect of age or sex on total tau or pTau181 levels. Overall, these results demonstrate the feasibility of evaluating blood biomarkers of neurodegeneration and inflammation in rhesus macaques during adulthood.

Longitudinal bidirectional association between hand grip strength and cognitive function in Chinese older adults: Evidence from the China health and retirement longitudinal study

ObjectiveThis study examined the longitudinal reciprocal association between handgrip strength and cognitive function and the temporal sequence of changes in both factors in a national longitudinal cohort of Chinese older adults.MethodData were derived from 3 waves (2011 baseline and 2013, 2015 follow-up) of the China Health and Retirement Longitudinal Study (CHARLS). Participants were those with no memory-related disorders at baseline and follow-up, and those who had complete handgrip strength and cognitive data. Handgrip strength in at least 1 hand was measured in all 3 waves. The highest recorded value during the handgrip test was used as the outcome of the strength measurement. Mental intactness and episodic memory were used to assess the overall cognitive function at each wave of data collection. Cross-lagged panel models were used to examine the relationship between handgrip strength and cognition over time.ResultsA total of 2550 participants were included in the data analysis. Age of participants at baseline was 60-83 years, and 43.9% were female (n = 1120). The 5.7% of participants with weak muscle strength (n = 145), had slightly lower cognitive function than those in the normal group. Cross-lag panel analysis showed that baseline overall cognitive scores predicted subsequent handgrip strength. At the same time, handgrip strength at baseline predicted subsequent overall cognitive scores. The results remained robust after accounting for confounding factors.ConclusionThere was a longitudinal bidirectional correlation between handgrip strength and cognitive function in elderly Chinese individuals. Future studies should determine whether interventions to improve 1 (e.g., handgrip strength) might slow the development of the other (e.g., cognitive function).

Differential response of tissue engineered skeletal muscle from rheumatoid arthritis patients and healthy controls

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting articular joints and skeletal muscle. To assess the role of cytokines upon muscle strength in RA, we developed an in vitro tissue-engineered human skeletal muscle model (myobundle). Myobundles were generated using primary skeletal muscle cells from the vastus lateralis muscle of RA patients and age-matched healthy controls. RA myobundles were more sensitive to 5 ng/mL IFN-γ, exhibiting reduced contractile force and altered contraction kinetics. Addition of IL-6 with or without IFN-γ led to a small but significant increase in striated fibers. Gene sets involved in the response to hypoxia, MTOR1 signaling, and the unfolded protein response were enriched in IFN-γ-treated RA myobundles, but not IFN-γ-treated controls. Tofacitinib increased contractile force, myosin heavy chain, and PIM1 protein levels in RA myobundles treated with IFN-γ. Thus, in RA muscle, low levels of IFN-γ selectively increase gene pathways that reduce contractile force.

Changes and trends in mortality, disability-adjusted life years, life expectancy, and healthy life expectancy in China from 1990 to 2021: a secondary analysis of the global burden of disease 2021

BACKGROUND

The aging population in China is increasingly evident, leading to a shift in the patterns of disease burden. This study aims to investigate changes and trends in mortality, disability-adjusted life years (DALYs), life expectancy (LE), and health-adjusted life expectancy (HALE) in China from 1990 to 2021.

METHODS

This study presents a secondary analysis of data from the Global Burden of Disease Study 2021, with a focus on mortality, DALYs, LE, and HALE. We examined changes in these indicators in China from 1990 to 2021, comparing them with global averages and across five SDI regions. Using Joinpoint Regression Software, we analyzed trends in the top ten cause-specific DALY rates in 2021. Furthermore, we employed the Bayesian Age-Period-Cohort model to forecast age-standardized rates (ASR) of mortality for the next decade.

RESULTS

China witnessed a decrease in the ASRs of mortality (1198.16/100,000 [1098.61-1294.10] to 644.68/100,000 [555.12-735.51]) and DALYs (43085.42/100,000 [39330.62-47273.39] to 22717.19/100,000 [19748.18-25903.34]) from 1990 to 2021. During the COVID-19 pandemic, the ASRs of mortality and DALY declined in China (23009.47/100,000 [19661.21-26495.58] in 2019), but global rates and those across the five SDI (Socio-demographic Index) regions increased. Projections indicate a continued decline in the ASRs of mortality over the next decade, from 2019 to 2035 and 2021 to 2035. Notably, DALY rates for the top 10 level 2 causes in 2021 decreased over the past three decades, except for musculoskeletal disorders (AAPC% 95%CI, 0.10 [0.07-0.14], men; 0.05 [-0.02-0.13], women) and sense organ diseases (AAPC% 95%CI, 0.38 [0.33-0.43], men; 0.35 [0.30-0.41], women). LE and HALE increased across all age groups in China over the same period, although there was no significant change in the HALE/LE ratio.

CONCLUSION

Effective policy implementation and technological advancements could play a crucial role in alleviating disease burdens associated with aging in China, thereby reducing the country's all-cause mortality rate and enhancing the quality of life for its residents.

Handgrip strength assessment in geriatric populations: digital dynamometers comparative study

BACKGROUND/OBJECTIVES

Handgrip strength is a critical indicator of overall health, particularly in older adults, and is associated with frailty, sarcopenia and risk of adverse health outcomes. Precise and reliable measurement instruments are necessary to ensure accuracy in personalised diagnostic evaluations. This study aimed to assess the inter-instrument reliability and agreement between the Jamar Plus+ digital and Jamar hydraulic dynamometers in measuring handgrip strength.

METHODS

A cross-sectional study was conducted to assess the handgrip strength of older individuals in the community aged more than 60, using the Jamar Plus+ digital and Jamar hydraulic dynamometers. The inter-instrument reliability and agreement between the devices were evaluated using Intraclass Correlation Coefficients (ICCs) and Bland-Altman analysis.

RESULTS

A total of 109 participants with a mean age of 66±5.3 years were included in this study. The Jamar Plus+ digital dynamometer recorded significantly higher handgrip strength measurements (27.0±7.1 kg) compared with the Jamar hydraulic dynamometer (21.0±6.7 kg). The ICCs between the two devices ranged from 0.67 to 0.70, indicating moderate reliability. Bland-Altman analysis revealed a consistent overestimation of handgrip strength by the Jamar Plus+ digital dynamometer, with systematic biases of 4.8 kg in men and 6.26 kg in women compared with the Jamar hydraulic dynamometer.

CONCLUSION

The Jamar Plus+ digital dynamometer consistently overestimated handgrip strength compared with the Jamar hydraulic dynamometer, but both devices demonstrated moderate reliability. The Jamar Plus+ showed greater responsiveness to variations in strength. Selecting appropriate diagnostic tools is crucial for optimising individualised health assessments in older adults.

A predictive nomogram based on triglyceride glucose index to body mass index ratio for low appendicular skeletal muscle mass

The aim of this study was to investigate risk factors, develop, and assess the predictive nomogram for low appendicular skeletal muscle mass index (ASMI) in middle-aged and elderly populations. A total of 3,209 inpatients were divided into a Training Set (n = 2,407) and a Validation Set (n = 802). A nomogram was developed using R software for internal validation, and external validation was performed using the Validation Set. Gender (male), age, height, weight, triglyceride levels, alanine aminotransferase levels, alcohol consumption, and the triglyceride-glucose index to body-mass index ratio (TyG/BMI) were identified as predictors for the nomogram of low ASMI. In the Training Set, Q1-Q4 subgroups were performed for TyG/BMI, and logistic regression analysis showed that a TyG/BMI ratio greater than 0.37 was significantly associated with an increased risk of developing low ASMI (P < 0.001), with an area under the receiver operating characteristic curve (AUC) of 0.879 for the nomogram. In the Validation Set, the nomogram also demonstrated excellent calibration and discrimination, with an AUC of 0.881. Decision curve analysis (DCA) indicated excellent clinical utility of the nomogram. The study innovatively used TyG/BMI to predict low ASMI, which can reduce the impact of obesity on the diagnosis of sarcopenia. The nomogram can be effectively used to screen for possible sarcopenia in community settings. Due to the cross-sectional study design and unable to obtain complete data on the assessment of muscle strength, the predictive efficacy of our nomogram model requires further confirmation through external validation by large, multicenter prospective studies on sarcopenia population.

Identifying semaphorin 3C as a biomarker for sarcopenia and coronary artery disease via bioinformatics and machine learning

OBJECTIVE

Sarcopenia not only affects patients' quality of life but also may exacerbate the pathological processes of coronary artery disease (CAD). This study aimed to identify potential biomarkers to improve the combined diagnosis and treatment of sarcopenia and CAD.

METHODS

Datasets for sarcopenia and CAD were sourced from the Gene Expression Omnibus (GEO). Weighted gene co-expression network analysis (WGCNA) was used to identify key module genes. Functional enrichment analysis was conducted to explore biological significance. Three machine learning algorithms were applied to further determine candidate hub genes, including SVM-RFE, LASSO regression, and random forest (RF). Then, we generated receiver operating characteristic (ROC) curves to evaluate the diagnostic efficacy of the candidate genes. Moreover, mendelian randomization (MR) analysis was conducted based on GWAS summary data, along with sensitivity analysis to explore causal relationships.

RESULTS

WGCNA analysis identified 278 genes associated with sarcopenia and CAD. The results of the enrichment analysis indicated a complex interplay between RNA metabolism, signaling pathways, and cellular stress responses. Through machine learning methods and ROC curves, we identified the key gene semaphorin 3C (SEMA3C). MR analysis revealed that higher plasma levels of SEMA3C are associated with an increased risk of CAD (OR = 1.068, 95 % CI 1.012-1.128, P = 0.016) and low hand grip strength (HGS) (OR = 1.059, 95 % CI 1.010-1.110, P = 0.018) .

CONCLUSION

SEMA3C has been identified as a key gene for sarcopenia and CAD. This insight suggests that targeting SEMA3C may offer new therapeutic opportunities in related conditions.

Age-related breakdown in networks of inter-muscular coordination

Assessing inter-muscular coordination in older adults is crucial, as it directly impacts an individual's ability for independent functioning, injury prevention, and active engagement in daily activities. However, the precise mechanisms by which distinct muscle fiber types synchronize their activity across muscles to generate coordinated movements in older adults remain unknown. Our objective is to investigate how distinct muscle groups dynamically synchronize with each other in young and older adults during exercise. Thirty-five young adults and nine older adults performed one bodyweight squat set until exhaustion. Simultaneous surface electromyography (sEMG) recordings were taken from the left and right vastus lateralis, and left and right erector spinae. To quantify inter-muscular coordination, we first obtained ten time series of sEMG band power for each muscle, representing the dynamics of different muscle fiber types. Next, we calculated the bivariate equal-time Pearson's cross-correlation for each pair of sEMG band power time series across all leg and back muscles. The main results show (i) an overall reduction in the degree of inter-muscular coordination, and (ii) increased stratification of the inter-muscular network in older adults compared to young adults. These findings suggest that as individuals age, the global inter-muscular network becomes less flexible and adaptable, hindering its ability to reorganize effectively in response to fatigue or other stimuli. This network approach opens new avenues for developing novel network-based markers to characterize multilevel inter-muscular interactions, which can help target functional deficits and potentially reduce the risk of falls and neuro-muscular injuries in older adults.

A Novel Research Paradigm for Sarcopenia of Limb Muscles: Lessons From the Perpetually Working Diaphragm's Anti-Aging Mechanisms

BACKGROUND

Skeletal muscle function and mass continuously decrease during aging. Most studies target limb muscles owing to their direct impact on mobility and falls risk. The diaphragm (DIA), also a type of skeletal muscle with different phenotype, has received less attention. Comparative research of the DIA and limb muscles can reveal their distinct aging characteristics. Critically, the potential endogenous anti-aging mechanisms of DIA that may provide new insights into the mechanisms of sarcopenia in limb muscles remain scarce.

METHODS

Treadmill and grip tests assessed limb muscle function, while a lung function system evaluated respiratory function in both adult (6-month-old) and old (22-month-old) mice. Histological assessments evaluated muscle mass in both the DIA and tibialis anterior (TA). Transcriptome sequencing identified differentially expressed genes (DEGs) between the DIA and TA with aging. Adeno-associated virus (AAV)-encoding short hairpin (sh) RNA targeting gene was injected into adult mice's TA muscles to knockdown target gene level in TA, and AAV-gene was injected into old mice's TA to overexpress target gene level.

RESULTS

Old mice displayed significantly reduced running distance (p = 0.0026), maximal speed (p = 0.0019), time to exhaustion (p = 0.0033) and grip strength (p = 0.0055) compared with adult mice, alongside TA's weight loss, decreased myofibre cross-sectional area (CSA) and autophagy deficiency. However, lung function indicators (respiratory rate, tidal volume, minute ventilation volume, forced vital capacity and ratio of forced expiratory volume in 100 or 200 ms to forced vital capacity), as well as DIA weight and morphology remained stable in old mice. Transcriptional analysis revealed 61 DEGs, with significant upregulation or downregulation observed in TA, but without changes in DIA during aging. Smox (spermine oxidase) is one of the DEGs, responsible for catalysing the conversion of spermine to spermidine. It was reported that in muscle atrophy models such as limb immobilisation, fasting and denervation, Smox's levels are positively correlated with muscle mass and function. Additionally, an increase in Smox also promotes mitochondrial biogenesis. In our study, AAV-shSmox adult mice decreased running distance, speed and time, myofibre CSA alongside mitochondrial function, compared with controls. In contrast, old mice with Smox overexpression showed enhanced mitochondrial function.

CONCLUSIONS

In conclusion, this study reveals aging diversities of TA and DIA, explores the sarcopenia of limb muscles based on the anti-aging properties of DIA, which offers a novel perspective on limb sarcopenia. Our findings suggest Smox as a potential target for developing strategies to mitigate sarcopenia progression.

Genetic determinants of muscle health: A population-based study

BACKGROUND

Muscle mass is associated with physical and functional performance across adulthood. Its reduction plays a crucial role in the development of age-related conditions such as frailty and sarcopenia. Genetic variations potentially impact muscle health, particularly in an aged population.

OBJECTIVES

For this reason, we aimed to evaluate the association between genetic biomarkers and appendicular lean mass index (ALMI), a marker of muscle health, to identify possible risk factors for age-related sarcopenia in a population-based study.

MATERIALS AND METHODS

We cross-sectionally analyzed data collected in 2015 from the São Paulo Epidemiologic Sleep Study (EPISONO). Participants underwent bioelectrical impedance and genetic evaluations.

RESULTS

After adjusting the data for age and sex, 12 single nucleotide polymorphisms (SNP) were significantly associated with ALMI. Among them, rs9928094 (beta = -0.031 p = 0.029) and rs9930333 (beta = -0.030 p = 0.035) are located in the FTO gene, which is related to obesity and fat gain and, rs16839632 (beta = 0.038 p = 0.029) located in the FMN2 gene, responsible for actin cytoskeleton and cell polarity.

CONCLUSIONS

Poor muscle health is a multifactorial condition and genetic biomarkers can support the stratification of the risk for adverse body composition states affecting muscle and physical performance across adulthood.

Sex Differences in Response to a 12-Week Resistance Training Exercise Intervention After Cardiac Surgery: A Proof-of-Concept Intervention Trial

PURPOSE

Cardiopulmonary rehabilitation, which often follows major acute cardiac events, is traditionally focused on aerobic exercise and has been associated with decreased morbidity and mortality. Its benefit among cardiac surgery patients is less clear, as is the role of resistance-based exercise programs and their sex-specific effects. This study seeks to evaluate the safety and feasibility of a 12-week resistance training program in patients post cardiac surgery through a sex-specific lens.

METHODS

We conducted a nonrandomized feasibility trial with a 12-week strength training exercise intervention. The primary outcome was safety and feasibility. Secondary outcomes included changes in strength, endurance, and functional capacity; and sex differences among these. Adult participants post open-heart surgery who had completed traditional cardiac rehabilitation were consented. Both patients who completed (cases) or did not complete (controls) a tailored 12-week resistance training program underwent comprehensive assessment of physiologic and physical fitness measures pre- and postintervention.

FINDINGS

Nine participants enrolled in the trial, including 6 in the intervention arm (median age 61 years; 67% male) and 3 in the control arm (median age 66 years; 67% male). No serious adverse events were noted, indicating safety of the intervention. Participants completed a mean of 34.8/36 (96.7%) of sessions, indicating the feasibility of the program. Although not powered for statistical significance, patients experienced positive trends of improvement in measures of hand grip strength, endurance, and functional capacity with the intervention. When stratified, females experienced greater gains than males in these measures.

IMPLICATIONS

This proof-of-concept study found that resistance-based exercise after cardiac surgery is well tolerated and feasible. Although all patients experienced improvements in exercise parameters, females reported greater relative improvement than males.

Age-related increase in the excitability of mouse layer V pyramidal neurons in the primary motor cortex is accompanied by an increased persistent inward current

Sarcopenia, or pathological age-related loss of muscle strength and mass, contributes to physical function impairment in older adults. While current understanding of sarcopenia is centered mostly on neuromuscular mechanisms, mounting evidence supports that deficits at the level of the primary motor cortex (PMC) play a significant role. Despite the importance of the PMC to initiate movement, understanding of how age affects the excitability of layer V pyramidal neurons (LVPNs) of the PMC is limited. To address this, we used the whole-cell patch clamp technique to measure the excitability of LVPNs of the PMC in young, late adulthood, and old mice. Old LVPNs had increased firing frequency and membrane input resistance, but no differences in action potential kinetics versus young and late adulthood mice. Since changes in the persistent inward current (PIC) are known to contribute to changes in motor neuron excitability, we measured LVPN PICs as a putative contributor to LVPN excitability. The PIC amplitude was increased in old LVPN via increases in Na+ and Ca2+ PICs, in addition to being active across a wider voltage range. Given that LVPN function is integral to initiation of voluntary muscle contraction, altered LVPN excitability likely contributes to age-related impairment of physical function.

Systemic aging fuels heart failure: Molecular mechanisms and therapeutic avenues

Systemic aging influences various physiological processes and contributes to structural and functional decline in cardiac tissue. These alterations include an increased incidence of left ventricular hypertrophy, a decline in left ventricular diastolic function, left atrial dilation, atrial fibrillation, myocardial fibrosis and cardiac amyloidosis, elevating susceptibility to chronic heart failure (HF) in the elderly. Age-related cardiac dysfunction stems from prolonged exposure to genomic, epigenetic, oxidative, autophagic, inflammatory and regenerative stresses, along with the accumulation of senescent cells. Concurrently, age-related structural and functional changes in the vascular system, attributed to endothelial dysfunction, arterial stiffness, impaired angiogenesis, oxidative stress and inflammation, impose additional strain on the heart. Dysregulated mechanosignalling and impaired nitric oxide signalling play critical roles in the age-related vascular dysfunction associated with HF. Metabolic aging drives intricate shifts in glucose and lipid metabolism, leading to insulin resistance, mitochondrial dysfunction and lipid accumulation within cardiomyocytes. These alterations contribute to cardiac hypertrophy, fibrosis and impaired contractility, ultimately propelling HF. Systemic low-grade chronic inflammation, in conjunction with the senescence-associated secretory phenotype, aggravates cardiac dysfunction with age by promoting immune cell infiltration into the myocardium, fostering HF. This is further exacerbated by age-related comorbidities like coronary artery disease (CAD), atherosclerosis, hypertension, obesity, diabetes and chronic kidney disease (CKD). CAD and atherosclerosis induce myocardial ischaemia and adverse remodelling, while hypertension contributes to cardiac hypertrophy and fibrosis. Obesity-associated insulin resistance, inflammation and dyslipidaemia create a profibrotic cardiac environment, whereas diabetes-related metabolic disturbances further impair cardiac function. CKD-related fluid overload, electrolyte imbalances and uraemic toxins exacerbate HF through systemic inflammation and neurohormonal renin-angiotensin-aldosterone system (RAAS) activation. Recognizing aging as a modifiable process has opened avenues to target systemic aging in HF through both lifestyle interventions and therapeutics. Exercise, known for its antioxidant effects, can partly reverse pathological cardiac remodelling in the elderly by countering processes linked to age-related chronic HF, such as mitochondrial dysfunction, inflammation, senescence and declining cardiomyocyte regeneration. Dietary interventions such as plant-based and ketogenic diets, caloric restriction and macronutrient supplementation are instrumental in maintaining energy balance, reducing adiposity and addressing micronutrient and macronutrient imbalances associated with age-related HF. Therapeutic advancements targeting systemic aging in HF are underway. Key approaches include senomorphics and senolytics to limit senescence, antioxidants targeting mitochondrial stress, anti-inflammatory drugs like interleukin (IL)-1β inhibitors, metabolic rejuvenators such as nicotinamide riboside, resveratrol and sirtuin (SIRT) activators and autophagy enhancers like metformin and sodium-glucose cotransporter 2 (SGLT2) inhibitors, all of which offer potential for preserving cardiac function and alleviating the age-related HF burden.

Comparative Analysis of Primary Sarcopenia and End-Stage Renal Disease-Related Muscle Wasting Using Multi-Omics Approaches

BACKGROUND

Age-related primary sarcopenia and end-stage renal disease (ESRD)-related muscle wasting are discrete entities; however, both manifest as a decline in skeletal muscle mass and strength. The etiological pathways differ, with aging factors implicated in sarcopenia and a combination of uremic factors, including haemodialysis, contributing to ESRD-related muscle wasting. Understanding these molecular nuances is imperative for targeted interventions, and the integration of proteomic and metabolomic data elucidate these intricate processes.

METHODS

We generated detailed clinical data and multi-omics data (plasma proteomics and metabolomics) for 78 participants to characterise sarcopenia (n = 28; mean age, 72.6 ± 7.0 years) or ESRD (n = 22; 61.6 ± 5.5 years) compared with controls (n = 28; 69.3 ± 5.7 years). Muscle mass was measured using bioelectrical impedance analysis and handgrip strength. Five-times sit-to-stand test performance was measured for all participants. Sarcopenia was diagnosed in accordance with the 2019 Consensus Guidelines from the Asian Working Group for Sarcopenia. An abundance of 234 metabolites and 722 protein groups was quantified in all plasma samples using liquid chromatography with tandem mass spectrometry.

RESULTS

Muscle mass, handgrip strength and lower limb muscle function significantly lower in the sarcopenia group and the ESRD group compared with those in the control group. Metabolomics revealed altered metabolites, highlighting exclusive differences in ESRD-related muscle wasting. Metabolite set enrichment analysis revealed the involvement of numerous metabolic intermediates associated with urea cycle, amino acid metabolism and nucleic acid metabolism. Catecholamines, including epinephrine, dopamine and serotonin, are significantly elevated in the plasma of patients within the ESRD group. Proteomics data exhibited a clearer distinction among the three groups compared with the metabolomics data, particularly in distinguishing the control group from the sarcopenia group. The ciliary neurotrophic factor receptor was top-ranked in terms of the variable importance of projection scores. Plasma AHNAK protein levels was higher in the sarcopenia group but was lower in the ESRD group. Proteomic set enrichment analysis revealed enrichment of several pathways related to sarcopenia, such as hemopexin, defence response and cell differentiation, in sarcopenia group. Multi-omic integration analysis revealed associations between relevant metabolites, including catecholamines, and a group of annotated proteins in extracellular exosomes.

CONCLUSIONS

We identified distinct multi-omic signatures in individuals with ESRD or sarcopenia, providing new insights into the mechanisms underlying ESRD-related muscle wasting, which differ from primary sarcopenia. These findings may support interventions for context-dependent muscle loss and contribute to the development of targeted treatments and preventive strategies for muscle wasting.

Combined effects of natural products and exercise on apoptosis pathways in obesity-related skeletal muscle dysfunction

Obesity and related metabolic disorders are closely linked to increased apoptosis in skeletal muscle, leading to muscle degeneration, insulin resistance, and the progression of diseases such as type 2 diabetes and sarcopenia. This review explores the combined effects of natural products, including resveratrol, curcumin, and quercetin, and physical exercise on modulating apoptosis pathways in skeletal muscle. Both natural products and regular physical activity independently reduce oxidative stress and improve mitochondrial function, thereby regulating the balance between pro-apoptotic and anti-apoptotic signals. When combined, these interventions amplify their protective effects on muscle health, promoting mitochondrial biogenesis, reducing apoptosis, and enhancing muscle regeneration. This review also discusses the molecular mechanisms by which these strategies influence apoptosis, with a focus on the Bcl-2 pathway, and explores the clinical implications for the prevention and treatment of obesity-related diseases. The synergistic benefits of combining exercise with natural product supplementation offer a promising therapeutic approach for managing metabolic disorders, preserving muscle function, and improving overall metabolic health.

Genetically Engineered Hypoimmune Human Muscle Progenitor Cells Can Reduce Immune Rejection

Cells face two challenges after transplantation: recognition and killing by lymphocytes, and cell apoptosis induced by the transplantation environment. Our hypoimmune cells aim to address these two challenges through editing of immunomodulatory proteins and overexpression of anti-apoptotic proteins.

An Overview of Sarcopenia: Focusing on Nutritional Treatment Approaches

Sarcopenia is a syndrome characterized by the progressive and generalized loss of skeletal muscle mass and strength. This condition is associated with physical disability, decreased quality of life, and increased mortality. Therefore, reducing the prevalence of sarcopenia could significantly lower healthcare costs. Sarcopenia can be classified into primary and secondary sarcopenia. The former is related to aging and begins after the fourth decade of life; after that, there is a muscle loss of around 8% per decade until age 70 years, which subsequently increases to 15% per decade. On the other hand, secondary sarcopenia can affect all individuals and may result from various factors including physical inactivity, malnutrition, endocrine disorders, neurodegenerative diseases, inflammation, and cachexia. Understanding the multiple mechanisms involved in the onset and progression of sarcopenia allows for us to develop strategies that can prevent, treat, or at least mitigate muscle loss caused by increased protein breakdown. One potential treatment of sarcopenia is based on nutritional interventions, including adequate caloric and protein intake and specific nutrients that support muscle health. Such nutrients include natural food rich in whey protein and omega-3 fatty acids as well as nutritional supplements like branched-chain amino acids, β-hydroxy-β-methylbutyrate, and vitamin D along with food for special medical purposes. It is important to emphasize that physical exercises, especially resistance training, not only promote muscle protein synthesis on their own but also work synergistically with nutritional strategies to enhance their effectiveness.

Six Weeks to Wellness: The Role of Breathing Exercises Based on Motor Development Pattern in Improving Fitness and Quality of Life in Overweight Elderly Women

Background: Being overweight is a major global health epidemic of the 20th and 21st centuries, which can affect the movement system function of older adult women. This study evaluated the effects of a breathing exercise based on motor development patterns on functional fitness and quality of life in overweight older adult women. Methods: A randomized controlled trial was conducted with 40 community-dwelling women aged 65-75. Participants were randomly assigned to an intervention group, which completed a 6-week breathing exercise program (three supervised and three home-based sessions per week), or a control group, which maintained usual routines. Outcome measures included cardiovascular fitness, upper and lower body flexibility, muscle strength, dynamic balance, and quality of life, assessed at baseline and post-intervention. Results: The intervention group showed significant improvements in cardiovascular fitness (p < .001, ES = 0.652), upper body flexibility (p < .001, ES = 0.652), lower body flexibility (p < .001, ES = 0.538), upper body strength (p < .001, ES = 0.538), lower body strength (p < .001, ES = 0.538), and dynamic balance (p < .001, ES = 0.475) compared to the control group. Quality of life also significantly improved in the intervention group (p < .001, ES = 0.475). Conclusion: Breathing exercises based on motor development patterns significantly enhance functional fitness and quality of life in overweight older adult women. Incorporating these exercises into regular physical activity routines may promote health and independence in older adults. Further research should explore long-term benefits and optimal exercise parameters for older adults.

Association of serum uric acid with handgrip strength and dynapenia in postmenopausal women

OBJECTIVE

This study aimed to examine the association of serum uric acid levels with handgrip strength (HGS) and dynapenia in postmenopausal women.

METHODS

A cross-sectional study among 422 participants collected data on age, age at menopause, adiposity, alcohol consumption, body mass index, current smoking status, HGS (measured using a digital dynamometer) and physical activity. Serum levels of creatinine, glucose, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, thyroid-stimulating hormone and uric acid were evaluated. Women were categorized into quartiles. A directed acyclic graph was designed to identify confounding variables. Multivariable regression analysis was used to assess associations between uric acid with HGS or dynapenia.

RESULTS

Women with hyperuricemia presented significant association with lower HGS (p = 0.00028). After adjusting for potential confounders, the multivariable linear regression to analyze the association between uric acid and HGS showed an inverted U-shaped curve, with quartile 1 (β = -0.54; 95% confidence interval [CI]: -1.50, 0.40), quartile 3 (β = -0.21; 95% CI: -1.20, 0.74) and quartile 4 (β = -1.3; 95% CI: -2.3, -0.37) compared with quartile 2. Serum uric acid levels were significantly associated with HGS (p = 0.036).

CONCLUSIONS

The association between uric acid quartiles with HGS or dynapenia displayed an inverted U-shaped curve. These findings suggest that specific serum uric acid levels within the normal range are associated with better HGS.

Global burden of injury due to low bone mineral density in adults aged 55 years and older, 1990 to 2021: A population-based study

OBJECTIVES

This study aimed to assess the global burden of injuries due to low bone mineral density (BMD) among adults aged 55 and above from 1990 to 2021, focusing on mortality and disability-adjusted life years (DALYs) and analyzing trends across sexes, age groups, and sociodemographic index (SDI) regions.

METHODS

Data from the Global Burden of Disease Study 2021, covering 204 countries and territories, were analyzed. Joinpoint regression quantified temporal changes in mortality and DALYs, calculating average annual percentage change (AAPC). Age-period-cohort modeling elucidated demographic influences, and decomposition analysis identified key contributors to mortality changes.

RESULTS

Globally, in 2021, the crude DALY rate for injuries due to low BMD was 900.32 (95 % UI: 742.64 to 1081.51) per 100,000, and the crude mortality rate was 27.04 (95 % UI: 22.49 to 30.75) per 100,000. The age-standardized mortality rate for injuries due to low BMD showed no significant change from 1990 to 2021 (AAPC 0.26 %, P = 0.071), but there was a significant increase in countries with a high SDI (AAPC 0.51 %, P = 0.001). The burden of disease in persons aged 80 years and older remained substantial, with a slight increase. Decomposition analysis identified population growth as the main driver of increasing mortality and DALYs.

CONCLUSION

Despite the reductions in DALY rates, the mortality has remained stable worldwide; however, has risen significantly in high SDI countries. The substantial and slightly increasing burden of disease in people aged 80 years and older underscores the need for targeted strategies for the prevention and management of low BMD to mitigate the future global impact of these injuries.

Paired corticospinal-motoneuronal stimulation enhances ballistic motor learning and corticospinal plasticity in older adults

Late adulthood is accompanied by declines in manual motor performance and reduced neuroplasticity, which can influence the effects of motor practice and learning. Corticomotoneuronal (CM) connectivity can be targeted non-invasively through individualized paired corticospinal-motoneuronal stimulation (PCMS) to prime ballistic motor learning in young adults. However, the priming effects of PCMS on motor output and ballistic motor learning in older adults remain unexplored. Part one of this study investigates ballistic motor performance and learning in young (20-30 years) and older (65-75 years) adults as within-session changes in peak acceleration of rapid index finger flexions and delayed retention 1 week later. The results demonstrate that older adults display lower maximal acceleration compared to young adults and smaller improvements with practice, indicating inferior learning and low levels of delayed retention. Part two of the study investigates the effects of PCMS on motor learning and corticospinal excitability in older adults. Corticospinal excitability was assessed throughout the experiment by recording motor evoked potentials from the first dorsal interosseous. PCMS increased subsequent ballistic learning and corticospinal excitability after practice compared to SHAM. Importantly, combined PCMS and motor practice also enhanced long-term retention, and performance remained enhanced 7 days later. This means that PCMS effectively reinstated the otherwise absent long-term learning in older adults. We demonstrate that PCMS primes experience-dependent plasticity accompanying motor learning resulting in long-term benefits on motor performance in older adults. These findings highlight the potential of PCMS to enhance the effects of motor practice and benefit functional abilities in older adults. KEY POINTS: Late adulthood is associated with reduced activation of spinal motoneurons during vigorous movements, resulting in slower and less precise movements. Older adults (aged 65-75 years) display lower ballistic motor performance compared to younger adults (aged 20-30 years); furthermore, older adults exhibit smaller improvements during practice, and lower retention. A single session of paired corticospinal-motoneuronal stimulation (PCMS) increases corticospinal excitability and primes within-session ballistic motor learning in older adults. A single session of PCMS improves long-term retention following ballistic motor learning. We provide proof-of-principle that PCMS represents a potential strategy to enhance the effects of motor practice and counteract age-related decline in motor function.

The Effects of Concurrent Training Versus Aerobic or Resistance Training Alone on Body Composition in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis

Introduction and Aim: The beneficial effects of aerobic training (AT) on preventing excess fat mass, and of resistance training (RT) on skeletal muscle adaptation, are well established. However, the effects of concurrent training (CT) compared to AT or RT alone on body composition in middle-aged and older adults are less understood, and therefore, the focus of this meta-analysis. Methods: Three databases, including PubMed, Web of Science, and Scopus, were searched from inception to March 2024. Randomized trials were included if they compared CT versus either AT or RT, and included body composition measures such as fat mass, body fat percentage, waist circumference, visceral fat mass, lean body mass (LBM), muscle mass/volume, or muscle or muscle fiber cross-sectional area (CSA), in middle-aged (50 to <65 years) and older adults (≥65 years). Weighted mean differences (WMD) or standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated using random effects models. Results: A total of 53 studies involving 2873 participants were included. Overall, CT increased body weight and LBM significantly more, trending toward significantly larger increases in muscle mass and CSA, compared with AT alone. However, there were no significant differences between CT and RT alone, for body weight, BMI, body fat percentage, fat mass, waist circumference, or visceral fat mass. Conclusions: CT is as effective as AT for decreasing body fat measures and as effective as RT for increasing muscle mass in middle-aged and older adults, and it should be recommended accordingly.

Therapeutics for Sarcopenia and Functional Disabilities in Older Adults: A Review of Phase 4 Clinical Trials

Background

Sarcopenia significantly contributes to physical disability and reduced quality of life in older adults, leading to disability. Therapeutics used to manage sarcopenia can improve not only muscle health but also the overall functional capacity of individuals at risk of developing disabilities. This review focuses on the therapeutic interventions evaluated in phase 4 clinical trials to address sarcopenia and its associated disabilities in older adults.

Objective

To review and summarize the therapeutic agents tested in phase 4 clinical trials for the management of sarcopenia and their potential impact on reducing functional disabilities in older adults.

Methods

A review of phase 4 clinical trials was conducted on 6th November 2024, focusing on interventions for sarcopenia in older adults. Data on therapeutic agents, trial outcomes, and their effects on muscle mass, strength, and disability prevention were collected from clinicaltrials.gov database.

Results

Several therapeutic agents, including whey protein powder, eldecalcitol, testosterone enanthate, and Denosumab, have been tested in Phase 4 trials for their ability to enhance muscle mass and function in older adults with sarcopenia. Allopurinol and Pioglitazone were also studied for their potential to improve muscle metabolism, while Medrol (Methylprednisolone) and Levothyroxine offered supportive effects in inflammatory and metabolic disorders that exacerbate muscle loss. Moreover, combination therapies, such as nutritional supplementation with HMB and vitamin D, showed promise in improving muscle function. These interventions demonstrated varying degrees of efficacy in improving muscle strength, reducing physical disability, and enhancing overall functional capacity in older adults.

Conclusion

Therapeutic strategies targeting sarcopenia in older adults have the potential to reduce functional disabilities and improve quality of life. Phase 4 clinical trials provide valuable insights into the long-term safety and effectiveness of these treatments. Continued research and refinement of these therapies are essential to fully address the disabling effects of sarcopenia and promote healthy aging.

Growth hormone-deficient Ames dwarf mice resist sarcopenia and exhibit enhanced endurance running performance at 24 months

Ames dwarf mice (df/df) live 50% longer than normal littermates due to a genetic defect in growth hormone (GH) signaling. The enhanced longevity of Ames dwarfs has been studied extensively in an endocrinological context of cellular metabolism and increased resistance to oxidative stress (Bartke. World J Mens Health 37(1):19, 8; Bartke 2; BartkeJ Am Aging Assoc 23(4):219, 10; Bartke. World J Mens Health 39(3):454-465, 11; Brown-Borg et al. Nature 384(6604):33-33, 1; Masternak et al. 2018). However, the skeletal muscle system is relatively unexplored, the quality of which dictates metabolic homeostasis, permits movement and exercise, and exerts paracrine effects on other organs (Delmonico and Beck Am J Lifestyle Med 11(2):167-181, 25; Evans et al. GeroScience 46(1):183, 26; Kim and Kim. Endocrinol Metab (Seoul) 35(1):1-6, 15; Masternak et al. 2018). Here, we characterize the fitness capacity and skeletal muscle morphology of Ames mice to determine if previously established longevous effects of GH deficiency extend to skeletal muscle tissue. Mutually exclusive, age-matched cohorts of male Ames mice and wildtype controls performed grip strength, rotarod, and endurance running experiments over 6 months. The largest difference in physical performance was observed in endurance running capacity, where dwarf mice outperformed wildtype controls increasingly with age. Tibialis anterior (TA) muscles were evaluated for myofiber size, quality, and environment. Ames mice show reduced myofiber cross-sectional area (CSA) paired with increased myofibers per muscle. Dwarf myofiber populations are less heterogenous in size and seemingly resist sarcopenia, as skeletal muscle from aged individuals shows youthful morphological resemblance in mean myofiber CSA, size frequency distribution, and presence of fibrotic tissue. Declines in fitness performance and myofiber integrity were observable in age-matched wildtype controls. Utilizing an established longevity model to investigate skeletal muscle function and morphology is a novel approach to gaining insight into the seemingly inverse relationship between GH signaling and mammalian longevity.

Sleep duration, sleep disturbances and skeletal muscle mass change over time: A population-based longitudinal analysis in Peru

Background

The skeletal muscle has mainly a structural function and plays a role in human's metabolism. Besides, the association between sleep quality and muscle mass, in the form of sarcopenia, has been reported. This study aimed to assess whether changes of skeletal muscle mass (SMM) over time are associated with baseline sleep duration and disturbances in a resource-constrained adult Peruvian population.

Materials and Methods

Secondary analysis using information of a population-based intervention. The outcome was SMM assessed using bioimpedance and the second version of the Lee's formula. The exposures were baseline self-reported sleep duration (normal, short and long sleepers) and disturbances (sleep difficulties and awakening at nights). Crude and adjusted linear mixed models were used to assess the associations of interest, and coefficients (β) and 95% confidence intervales (95% CI) were reported.

Results

Data from 2,310 individuals at baseline, mean age 43.4 (SD: 17.2), and 1,163 (50.4%) females were analyzed. Sleep duration was 7.8 (SD: 1.3) hours/day, with 15.3% short sleepers and 11.6% long sleepers, whereas 24.2% reported sleep difficulties and 25.1% awakening at nights. In multivariable model, SMM among short and long sleepers did not vary significantly over time using the Lee's formula; however, SMM was lower at the end of follow-up for long sleepers using bioimpedance (-0.26 kg; 95% CI: -0.47 to -0.06). Sleep disturbances were associated with a gradual SMM reduction: 0.36 kg using bioimpedance and 0.25 kg using the formula at the end of follow-up.

Conclusions

Using bioimpedance and formula estimations, sleep disturbances were associated with a reduction of SMM over a period of 2.4 years. Regarding sleep duration, no SMM changes over time were seen in short sleepers, but findings were discordant in long sleepers: a reduction of SMM using bioimpedance, but no change using the formula.

Microgravity-induced changes in skeletal muscle and possible countermeasures: What we can learn from bed rest and human space studies

Despite exercise countermeasures to sustain health and performance in spaceflight, complete maintenance of muscle mass and functions in microgravity is still not possible for most astronauts. The principal cause of the limited effectiveness of existing exercise countermeasures is the difficulty in achieving full loading forces in space. The implementation of countermeasures which require small devices and simulate Earth-like loading forces to maintain muscle mass, strength and endurance is therefore highly desirable. At present, the cellular mechanisms that induce muscle atrophy in weightlessness are not yet fully known; a better understanding of how skeletal muscle cells adapt to microgravity will help in designing more effective countermeasures to sustain the health and operational capacity of the crew during long- and short-duration missions. The 6° head-down-tilt bed rest is a powerful ground-based analogue platform to simulate and study the physiological effects of spaceflight on the human body, and test the effectiveness of countermeasures before they are potentially applied in space. The aims of this narrative review are therefore to provide an overview of (i) the main mechanisms underlining muscle atrophy learnt from space and bed rest studies, (ii) the currently available countermeasures, and (iii) potential suitable countermeasures - such as neuromuscular electrical stimulation that is delivered with light and small portable units - to attenuate muscle wasting in astronauts during spaceflight.

Poncirus trifoliata Extract and Its Active Coumarins Alleviate Dexamethasone-Induced Skeletal Muscle Atrophy by Regulating Protein Synthesis, Mitochondrial Biogenesis, and Gut Microbiota

Sarcopenia, an age-related decline in skeletal muscle mass and function, contributes to frailty and increased morbidity in the elderly. This necessitates the development of effective interventions to combat muscle atrophy. This study investigated the therapeutic potential of Poncirus trifoliata ethanol extract (PT) and its coumarin derivatives against dexamethasone (DEX)-induced muscle atrophy. We employed in vitro and in vivo models of DEX-induced muscle atrophy. C2C12 myotubes were used for mechanistic studies. C57BL/6J mice received DEX injections and oral PT supplementation (50 mg/kg/day) to evaluate effects on muscle mass, function, gene expression, and gut microbiota composition. In vitro, PT enhanced protein synthesis, mitochondrial biogenesis, and myogenic differentiation in DEX-exposed myotubes, with auraptene, ponciol, and triphasiol identified as key bioactive coumarins. In vivo, PT significantly attenuated DEX-induced muscle atrophy, increasing tibialis anterior muscle mass by 36% (p < 0.01), grip strength by 31% (p < 0.001), and maximal running speed by 18% (p < 0.05). Mechanistically, PT upregulated genes associated with muscle function and mitochondrial health. Furthermore, PT modulated gut microbiota composition, notably increasing Phocaeicola vulgatus abundance 2.2-fold, which correlated with improved muscle performance (R = 0.58, p < 0.01). These findings suggest that PT and its coumarin derivatives, particularly auraptene, ponciol, and triphasiol, hold promise as therapeutic agents for combating muscle atrophy. The observed benefits may be mediated through enhanced protein synthesis, improved mitochondrial function, and modulation of the gut-muscle axis.

Aerobic Exercise Training, Biological Age, and Mortality in Chronic Heart Failure With Reduced Ejection Fraction

BACKGROUND

Among individuals with chronic heart failure with reduced ejection fraction (HFrEF), the predictive value for mortality by biomarker-based biological age (BA) and whether aerobic exercise training (AET) modifies the association are understudied.

OBJECTIVES

The authors aimed to investigate the association between BA and mortality among individuals with HFrEF and assess whether AET modifies the association.

METHODS

Including participants in HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training), BA acceleration was constructed by the Klemera-Doubal method, using the residual of a linear model of BA and chronological age. The associations between BA and all-cause mortality, cardiovascular death, and all-cause hospitalization were investigated by treating BA acceleration into continuous and quintiles in the overall cohort.

RESULTS

Among the 1,732 individuals, during a median of 31.5 (IQR: 20.7-43.1) months of follow-up, 301 deaths were observed. A 1-SD increase in BA acceleration was associated with a 31% higher risk of all-cause mortality (HR: 1.31; 95% CI: 1.13-1.51), a 31% higher risk of cardiovascular mortality (HR: 1.31; 95% CI: 1.12-1.54), and a 9% higher risk of all-cause hospitalization (HR: 1.09; 95% CI: 1.01-1.17). The association of all-cause mortality was significantly different between treatment arms (P interaction = 0.024). BA acceleration was associated with a 53% higher risk of all-cause mortality in usual care (HR: 1.53; 95% CI: 1.25-1.89), but the association was not significant in AET (HR: 1.10; 95% CI: 0.89-1.36).

CONCLUSIONS

Among individuals with HFrEF, BA has a good prediction value in HFrEF endpoints. AET may be associated with a reduction in all-cause mortality driven by aging.

Physical activity reverses the aging induced decline in angiogenic potential in the fast locomotory muscles of mice

Fast locomotory muscles, which are responsible for generating the highest power outputs, are more vulnerable to aging than slow muscles. In this study, we aimed to evaluate the impact of middle age and voluntary physical activity on capillarization and angiogenic potential in fast locomotory muscles. Middle-aged (M-group) and young (Y-group) wild-type FVB female mice were randomly assigned to either the sedentary or trained group undergoing 8-week spontaneous wheel running (8-sWR). Capillary density (assessed via immunohistochemical capillary staining and Western immunoblotting) of the fast locomotory muscles in the M-group (15-months old) was not significantly different compared to the Y-group (4-months old). Nevertheless, the expression of key pro-angiogenic genes in the fast muscle of the M-group was lower than that in the fast muscle of Y-group. 8-sWR had no impact on muscle capillarization; however, it increased fast muscle Vegfa expression in both the M and Y groups. We concluded that although fast muscle capillarization is still preserved in middle age, nevertheless the angiogenic potential (at least at the level of gene expression) is significantly reduced at this stage of aging. Moderate-intensity voluntary physical activity had no effect on capillary density, but it increased the angiogenic potential of the fast muscle.

YAP/TAZ-mediated nuclear membrane rupture in promoting senescence of skeletal muscle associated with COPD

Patients with chronic obstructive pulmonary disease (COPD) often develop complications associated with sarcopenia; however, the underlying mechanisms remain unclear. Through a combination of in vitro and in vivo experiments, as well as bioinformatics analysis, our study identified YAP/TAZ as a key regulator of the aging phenotype in the skeletal muscle of COPD patients. In skeletal muscle affected by cigarette smoke-induced COPD, we observed significant reductions in YAP/TAZ levels, alongside markers indicative of skeletal muscle aging and dysfunction. Notably, overexpression of YAP/TAZ significantly improved these conditions. Our results suggest a novel mechanism whereby the maintenance of YAP/TAZ activity interacts with ACTR2 to preserve nuclear membrane integrity and reduce cytoplasmic dsDNA levels, thereby attenuating STING activation and cellular senescence. Additionally, we found that YAP is involved in the transcriptional regulation of the ACTR2 promoter region. Overall, preserving YAP/TAZ activity may help prevent skeletal muscle aging associated with COPD, representing a new strategy for intervening in COPD-related sarcopenia.

Bile acid signaling in skeletal muscle homeostasis: from molecular mechanisms to clinical applications

The intricate relationship between bile acid metabolism and skeletal muscle function has emerged as a crucial area of research in metabolic health. This review synthesizes current evidence highlighting the fundamental role of bile acids as key signaling molecules in muscle homeostasis and their therapeutic potential in muscle-related disorders. Recent advances in molecular biology and metabolomics have revealed that bile acids, beyond their classical role in lipid absorption, function as essential regulators of muscle mass and function through multiple signaling pathways, particularly via the nuclear receptor FXR and membrane receptor TGR5. Clinical studies have demonstrated significant associations between altered bile acid profiles and muscle wasting conditions, while experimental evidence has elucidated the underlying mechanisms linking bile acid signaling to muscle protein synthesis, energy metabolism, and regeneration capacity. We critically examine the emerging therapeutic strategies targeting bile acid pathways, including receptor-specific agonists, microbiome modulators, and personalized interventions based on individual bile acid profiles. Additionally, we discuss novel diagnostic approaches utilizing bile acid-based biomarkers and their potential in early detection and monitoring of muscle disorders. This review also addresses current challenges in standardization and clinical translation while highlighting promising future directions in this rapidly evolving field. Understanding the bile acid-muscle axis may provide new opportunities for developing targeted therapies for age-related muscle loss and metabolic diseases.

Causal associations between Sarcopenia-related traits and obstructive sleep apnea: a mendelian randomization study

BACKGROUND

Evidence for a causal relationship between sarcopenia and obstructive sleep apnea (OSA) is scarce. This study aimed to investigate the causal association between sarcopenia-related traits and OSA utilizing Mendelian randomization (MR) analyses.

METHODS

MR analyses were conducted using genetic instruments for sarcopenia-related traits, including hand grip strength, muscle mass, fat mass, water mass, and physical performance. Data from large-scale genome-wide association studies (GWAS) were utilized to identify genetic variants associated with these traits. Causal associations with OSA were assessed using various MR methods, including the inverse variance-weighted (IVW) method, MR-Egger, and weighted median approaches. Pleiotropy and heterogeneity were evaluated through MR-PRESSO and other sensitivity analyses.

RESULTS

Low hand grip strength in individuals aged 60 years and older exhibited a positive correlation with the risk of OSA (IVW, OR = 1.190, 95% CI = 1.003-1.413, p = 0.047), while no significant causal effects were observed for grip strength in the left and right hands. Muscle mass, fat mass, and water mass were significantly associated with OSA, even after adjusting for multiple testing. Notably, higher levels of body fat percentage, trunk fat percentage, and limb fat percentage were strongly correlated with increased risk of OSA. Physical performance indicators such as walking pace demonstrated an inverse association with OSA, while a higher risk of OSA was observed with increased log odds of falling risk and greater frequency of falls in the last year. Additionally, a causal effect was found between long-standing illness, disability, or infirmity and OSA.

CONCLUSIONS

This comprehensive MR analysis provides evidence of a significant causal relationship between characteristics associated with sarcopenia, including low hand grip strength, muscle mass, fat mass, and physical performance, and the risk of OSA. These findings underscore the importance of addressing sarcopenia-related factors in the management and prevention of OSA.

The role of AGEs in muscle ageing and sarcopenia

Sarcopenia is an ageing-related disease featured by the loss of skeletal muscle quality and function. Advanced glycation end-products (AGEs) are a complex set of modified proteins or lipids by non-enzymatic glycosylation and oxidation. The formation of AGEs is irreversible, and they accumulate in tissues with increasing age. Currently, AGEs, as a biomarker of ageing, are viewed as a risk factor for sarcopenia. AGE accumulation could cause harmful effects in the human body such as elevated inflammation levels, enhanced oxidative stress, and targeted glycosylation of proteins inside and outside the cells. Several studies have illustrated the pathogenic role of AGEs in sarcopenia, which includes promoting skeletal muscle atrophy, impairing muscle regeneration, disrupting the normal structure of skeletal muscle extracellular matrix, and contributing to neuromuscular junction lesion and vascular disorders. This article reviews studies focused on the pathogenic role of AGEs in sarcopenia and the potential mechanisms of the detrimental effects, aiming to provide new insights into the pathogenesis of sarcopenia and develop novel methods for the prevention and therapy of sarcopenia.

Alliaceae vegetable consumption and sarcopenia: findings from the TCLSIH cohort study

Background and aims: Sarcopenia is a progressive and degenerative loss of muscle mass and function in the elderly that is associated with increased adverse outcomes. Organosulfur compounds, obtained from Alliaceae vegetables, could protect skeletal muscle from atrophy because of their antioxidative and anti-inflammatory effects. Therefore, the present study aimed to investigate the association between Alliaceae vegetable consumption and sarcopenia in the general elderly population. Methods: This study used data from the TCLSIH cohort study (2017-2022). Alliaceae vegetable consumption was assessed using a validated self-administered food frequency questionnaire. Sarcopenia was defined using the Asian Working Group for Sarcopenia algorithm. Multiple logistic regression and Cox proportional hazards regression models were used for the cross-sectional analysis (n = 3623) and the prospective incident analysis (n = 1913), respectively. Results: There were 546 (15.1%) sarcopenic cases at baseline and 302 (56.1 per 1000 person years) incident sarcopenic cases over a mean follow-up of 2.8 years. In Model 4, the hazard ratios (HRs) (95% confidence interval [CI]) for incident sarcopenia across raw garlic consumption categories were 1.00 (reference) for almost never, 0.70 (0.53, 0.93) for ≤1 time per week, and 0.59 (0.44, 0.80) for ≥2-3 times per week (P for trend < 0.001); the HRs (95% CI) for sarcopenia across onion consumption categories were 1.00 (reference) for almost never, 0.71 (0.53, 0.97) for ≤1 time per week, and 0.73 (0.54, 0.97) for ≥2-3 times per week (P for trend = 0.02). Similar results were also observed in the cross-sectional analysis. Conclusion: The consumption of Alliaceae vegetables, including garlic and onion, is inversely associated with prevalent and incident sarcopenia. Further studies are needed to explore the causality.

Impact of Hospitalization on Sarcopenia, NADPH-Oxidase 2, Oxidative Stress, and Low-Grade Endotoxemia in Elderly Patients

BACKGROUND

Hospitalization in older adults often worsens sarcopenia due to prolonged bed rest, poor nutrition, and inactivity. This study examined how hospitalization impacts muscle mass, focusing on oxidative stress and gut-derived endotoxemia.

METHODS

Thirty-one hospitalized older adults were compared with 31 outpatients. Ultrasound was used to measure the thickness of the rectus femoris (RF), intercostal, and diaphragmatic muscles at admission and discharge. Serum levels of LPS, zonulin, sNOX2-dp, and H2O2 were also assessed.

RESULTS

Hospitalized patients had higher serum levels of sNOX2-dp, H2O2, LPS, and zonulin than outpatients. In hospitalized patients, significant increases were observed at discharge compared to admission levels in sNOX2-dp (20.9 ± 6.5 to 23.8 ± 7.5 pg/mL; p = 0.004), H2O2 (24.4 ± 9.8 to 32.8 ± 14.5 µM; p = 0.01), LPS (30.4 ± 12.6 to 43.3 ± 16.35 pg/mL; p < 0.001), and zonulin (2.06 ± 1.23 to 2.95 ± 1.33 ng/mL; p < 0.001). Ultrasound data revealed a reduction in RF muscle thickness (-35%) (0.58 ± 0.29 to 0.38 ± 0.31 cm, p < 0.001), intercostal muscle thickness (-28%) (0.22 ± 0.08 to 0.16 ± 0.06 cm, p < 0.001), and diaphragmatic muscle thickness (-26%) (0.19 ± 0.06 to 0.14 ± 0.04 cm, p < 0.001) at discharge compared to admission. Additionally, muscle strength, measured using the hand-grip test, showed a 25% reduction. Regression analysis revealed correlations between RF muscle loss and increases in sNOX2-dp and H2O2, as well as between NOX2, H2O2, and LPS with zonulin.

CONCLUSIONS

Hospitalization in older adult patients elevates NOX2 blood levels, correlating with reduced muscle mass. Increased low-grade endotoxemia may trigger NOX2 activation, generating oxidative stress that accelerates muscle degeneration and can lead to sarcopenia.

17β-Trenbolone Exposure Enhances Muscle Activity and Exacerbates Parkinson's Disease Progression in Male Mice

Parkinson's disease (PD) ranks as the second most prevalent neurodegenerative disorder, and while the neuroprotective effects of estrogen are well-documented, the impact of androgens on neurological disorders remains understudied. The consequences of exposure to 17-trenbolone (17-TB), an environmental endocrine disruptor with androgen-like properties, on the mammalian nervous system have received limited attention. Therefore, in this study, we aimed to investigate the biological effects of 17-TB exposure on PD. In our investigation using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model, we discovered that 17-TB exposure elevated testosterone hormone levels prevented androgen receptor (AR) reduction, upregulated the expression of muscular dystrophic factors (Atrogin1, MuRF1, Musa1, and Myostatin), improved muscle strength, and enhanced locomotor activity in the open field test. However, it is noteworthy that exposure to 17-TB also led to an upregulation of neuroinflammatory cytokines (NLRP3, IL-6, IL-1α, and IL-1β) in PD mice. Crucially, 17-TB exposure induced downregulation of nigral apoptotic proteins DJ-1 and Bcl-2 while upregulating Bax and Caspase-3 in PD mice. This exacerbated neuronal apoptosis, ultimately intensifying dopaminergic neuronal degeneration and death in the substantia nigra and striatum of PD mice. In conclusion, our findings indicate that while 17-TB mitigates muscle atrophy and enhances motor activity in PD mice, it concurrently exacerbates neuroinflammation, induces neuronal apoptosis, and worsens dopaminergic neuronal death, thereby aggravating the progression of MPTP-induced Parkinsonism. This underscores the importance of considering potential environmental risks in neurodegeneration associated with Parkinson's disease, providing a cautionary tale for our daily exposure to environmental endocrine chemical disruptors.

Rest-to-work and work-to-rest transients of interstitial PO2 in spinotrapezius muscle of young and old male rats

Muscle function declines with age. Since the primary energy source for contraction is aerobic, this study investigated age-related changes in muscle oxygenation dynamics to: characterize PO2 transients during rest-work transitions, identify age-specific differences in oxygen delivery/utilization balance, and examine the relationship between interstitial and arterial oxygen tension (PO2). Interstitial PO2 was measured with a high-resolution stroboscopic phosphorescence quenching technique to map intra-contractile dynamics during changes in muscle activity-rest-to-work (RtW) and work-to-rest (WtR) in rats aged three (young) and 23 (old) months. RtW (τw) and WtR (τr) PO2 transitions had lag periods and mono-exponential time constants. In young muscles, lag was 4 s, τw = 9.0 ± 3.7 s, and τr = 15.4 ± 3.9 s. For old, lag was also 4 s with increases to τw = 15.9 ± 3.5 s and τr = 41.4 ± 8.3 s. Resting PO2's were higher for young than for old (66.7 ± 13.7 vs. 60.2 ± 13.0 mmHg; p < 0.05). Work reduced PO2 with a greater effect on old (42.5 ± 14.0 vs. 28.3 ± 16.5 mmHg; p < 0.05). Intra-contractile measurements revealed a spike in PO2 (11 mmHg amplitude for >200 ms), which was absent in old. Further, sustained exercise in young showed a rising trend in PO2, while old remained at nadir. The missing PO2 spike in aged muscle contributes to reduced PO2 during work and may explain age-related loss of endurance.

Aqueous extract of Atractylodes macrocephala Koidz. improves dexamethasone-induced skeletal muscle atrophy in mice by enhancing mitochondrial biological function

PURPOSE

The study aims to investigate the therapeutic effects of the aqueous extract of Atractylodes macrocephala Koidz. (AEA) on dexamethasone (Dex) -induced sarcopenia in mice and to explore its possible mechanisms of action.

METHODS

This study utilized bioinformatics analysis to explore the primary pathogenic mechanisms of age-related sarcopenia and Dex-induced muscle atrophy. In animal experiments, a mouse model of muscle atrophy was established using Dex, and different doses of AEA were administered for treatment. The therapeutic effects of AEA were evaluated through tests of motor ability and histological analysis, and the molecular mechanisms predicted by bioinformatics were verified by measuring the expression levels of related genes.

RESULTS

Bioinformatics analysis suggests that there may be shared pathogenic mechanisms related to mitochondrial function and structure between age-related sarcopenia and Dex-induced muscle atrophy. Dex significantly reduced the mass, function, and cross-sectional area of muscle fibers in mice, and also induced changes in muscle fiber types. In contrast, AEA significantly ameliorated the aforementioned atrophic effects caused by Dex. The modulation of mitochondrial biogenesis and dynamics may be a crucial mechanism by which AEA exerts its anti-sarcopenia effects.

CONCLUSION

AEA can significantly alleviate the symptoms of Dex-induced skeletal muscle atrophy in mice by improving mitochondrial function, indicating its potential for clinical application in the prevention and treatment of age-related sarcopenia.

Multi-omic profiling of sarcopenia identifies disrupted branched-chain amino acid catabolism as a causal mechanism and therapeutic target

Sarcopenia is a geriatric disorder characterized by a gradual loss of muscle mass and function. Despite its prevalence, the underlying mechanisms remain unclear, and there are currently no approved treatments. In this study, we conducted a comprehensive analysis of the molecular and metabolic signatures of skeletal muscle in patients with impaired muscle strength and sarcopenia using multi-omics approaches. Across discovery and replication cohorts, we found that disrupted branched-chain amino acid (BCAA) catabolism is a prominent pathway in sarcopenia, which leads to BCAA accumulation and decreased muscle health. Machine learning analysis further supported the causal role of BCAA catabolic dysfunction in sarcopenia. Using mouse models, we validated that defective BCAA catabolism impairs muscle mass and strength through dysregulated mTOR signaling, and enhancing BCAA catabolism by BT2 protects against sarcopenia in aged mice and in mice lacking Ppm1k, a positive regulator of BCAA catabolism in skeletal muscle. This study highlights improving BCAA catabolism as a potential treatment of sarcopenia.

SIRT5 safeguards against primate skeletal muscle ageing via desuccinylation of TBK1

Ageing-induced skeletal muscle deterioration contributes to sarcopenia and frailty, adversely impacting the quality of life in the elderly. However, the molecular mechanisms behind primate skeletal muscle ageing remain largely unexplored. Here, we show that SIRT5 expression is reduced in aged primate skeletal muscles from both genders. SIRT5 deficiency in human myotubes hastens cellular senescence and intensifies inflammation. Mechanistically, we demonstrate that TBK1 is a natural substrate for SIRT5. SIRT5 desuccinylates TBK1 at lysine 137, which leads to TBK1 dephosphorylation and the suppression of the downstream inflammatory pathway. Using SIRT5 lentiviral vectors for skeletal muscle gene therapy in male mice enhances physical performance and alleviates age-related muscle dysfunction. This study sheds light on the molecular underpinnings of skeletal muscle ageing and presents the SIRT5-TBK1 pathway as a promising target for combating age-related skeletal muscle degeneration.

The Roles of myomiRs in the Pathogenesis of Sarcopenia: From Literature to In Silico Analysis

Senile sarcopenia is a condition of age-associated muscular disorder and is a significant health issue around the world. In the current review, we curated the information from the NCBI, PubMed, and Google Scholar literature and explored the non-genetic and genetic causes of senile sarcopenia. Interestingly, the myomiRs such as miR-1, miR-206, miR-133a, miR-133b, miR-208b, and miR-499 are skeletal muscle's critical structural and functional regulators. However, very scattered information is available regarding the roles of myomiRs in different skeletal muscle phenotypes through a diverse list of known target genes. Therefore, these pieces of information must be organized to focus on the conserved target genes and comparable effects of the myomiRs in regulating senile sarcopenia. Hence, in the present review, the roles of pathogenetic factors in regulating senile sarcopenia were highlighted. The literature was further curated for the roles of myomiRs such as hsa-miR-1-3p/206, hsa-miR-27-3p, hsa-miR-146-5p, and hsa-miR-499-5p and their target genes. Additionally, we used different bioinformatics tools and predicted target genes of the myomiRs and found the most critical target genes, shared pathways, and their standard functions in regulating muscle structure and functions. The information gathered in the current review will help the researchers to explore their possible therapeutic potential, especially the use of the myomiRs for the treatment of senile sarcopenia.

Valorization of fishery byproducts: Large-scale production of olive flounder functional protein ingredients and their effects on muscle regeneration

Use of olive flounder byproducts, which constitute nearly 50 % of the total fish mass, offers a promising strategy for maximizing protein-rich resources.In this study, we optimized a Prozyme 2000P® enzyme-assisted olive flounder byproduct hydrolysate (OFBP) for large-scale production using response surface methodology and evaluated its efficacy in muscle-atrophy models. The final OFBP exhibited 87.5 % protein content, with over 60 % of peptides under 700 Da, promoting high bioavailability and absorption. In vitro, OFBP (300 µg/mL) enhanced de novo protein synthesis in murine C2C12 myotubes by more than two-fold compared with the untreated control (p < 0.05). In a zebrafish model of dexamethasone-induced muscle atrophy, 1 % OFBP supplementation restored up to 80 % of normal activity levels and significantly increased muscle cross-sectional area relative to atrophic controls (p < 0.05). Lipidomic analysis further revealed that dexamethasone-associated elevations in ceramide and sphingomyelin were downregulated by OFBP, indicating a protective effect on sphingolipid metabolism. Taken together, these findings demonstrate that enzymatic hydrolysis of fish byproducts can yield a nutritionally rich ingredient that not only mitigates muscle atrophy through enhanced protein synthesis but also modulates lipid homeostasis. This work highlights OFBP as a sustainable, functional food candidate for supporting muscle health and addressing waste-utilization needs.

Resistance exercise training in older men reduces ATF4-activated and senescence-associated mRNAs in skeletal muscle

Sarcopenia increases the risk of frailty, morbidity, and mortality in older adults. Resistance exercise training improves muscle size and function; however, the response to exercise training is variable in older adults. The objective of our study was to determine both the age-independent and age-dependent changes to the transcriptome following progressive resistance exercise training. Skeletal muscle biopsies were obtained before and after 12 weeks of resistance exercise training in 8 young (24 ± 3.3 years) and 10 older (72 ± 4.9 years) men. RNA was extracted from each biopsy and prepared for analysis via RNA sequencing. We performed differential mRNA expression, gene ontology, and gene set enrichment analyses. We report that when comparing post-training vs pre-training 226 mRNAs and 959 mRNAs were differentially expressed in the skeletal muscle of young and older men, respectively. Additionally, 94 mRNAs increased, and 17 mRNAs decreased in both young and old, indicating limited overlap in response to resistance exercise training. Furthermore, the differential gene expression was larger in older skeletal muscle. Finally, we report three novel findings: 1) resistance exercise training decreased the abundance of ATF4-activated and senescence-associated skeletal muscle mRNAs in older men; 2) resistance exercise-induced increases in lean mass correlate with increased mRNAs encoding mitochondrial proteins; and 3) increases in muscle strength following resistance exercise positively correlate with increased mRNAs involved in translation, rRNA processing, and polyamine metabolism. We conclude that resistance exercise training elicits a differential gene expression response in young and old skeletal muscle, including reduced ATF-4 activated and senescence-associated gene expression.

Association between sarcopenia and cardiovascular disease according to menopausal status: findings from the China Health and Retirement Longitudinal Study (CHARLS)

BACKGROUND

Little is known about the association between sarcopenia and cardiovascular disease (CVD) according to menopausal status, and we conducted cross-sectional as well as longitudinal analyses Using nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS) to investigate the association between sarcopenia and CVD in Chinese women according to menopausal status.

METHOD

The study sample included 5365 (mean age 60.3 ± 9.3 years) female participants from CHARLS 2015 (wave 3). Additionally, 3,882 participants without cardiovascular disease (CVD) were recruited in CHARLS 2015 (Wave 3) and followed up in 2018 (Wave 4). CVD was defined as the presence of physician-diagnosed heart disease and/or stroke. Menopausal status was determined based on self-reported information from questionnaires. Sarcopenia status was assessed using the diagnostic criteria established by the Asian Working Group on Sarcopenia in 2019 (AWGS 2019). Binary logistic regression analyses were conducted to explore the association between sarcopenia and CVD in both premenopausal and postmenopausal women. Further analyses examined the interaction between sarcopenia and menopausal status to better understand its impact on CVD.

RESULTS

The prevalence of CVD in the total population is 22.5% (1209/5365). Among premenopausal women, the prevalence in no-sarcopenia, possible sarcopenia, and sarcopenia group are 11.3% (86/759), 16.2% (17/105), and 13.9% (5/36), respectively, for postmenopausal women, the prevalence are 19.2% (320/1668), 32.6% (520/1597), and 21.8% (261/1200). Both possible sarcopenia (OR = 1.58; 95% CI: 1.29-1.93) and sarcopenia (OR = 1.34; 95% CI: 1.05,1.72) are associated with CVD in the population of postmenopausal women. There was a significant positive interaction between menopause and sarcopenia on CVD, the RERI = 5.30 (95%CI: 4.63, 5.98), the SI = 2.44 (95%CI: 1.84, 3.63), and the multiplicative effect = 2.18 (95%CI: 1.70, 2.66). In the longitudinal analysis, 514 (13.2%) new cases of CVD were diagnosed. In premenopausal women, sarcopenia was significantly associated with the development of CVD (OR = 2.44, 95% CI: 1.3,4.59). In postmenopausal women, possible sarcopenia (OR = 1.45, 95% CI: 1.28, 1.65) and sarcopenia (OR = 1.42, 95% CI: 1.23, 1.65) were more likely to have new-onset CVD than the postmenopausal no-sarcopenia women.

CONCLUSIONS

Sarcopenia and cardiovascular disease (CVD) risk show significant variations in cross-sectional and longitudinal associations across different menopausal statuses, with higher risks in postmenopausal women. An interaction between menopausal status and sarcopenia on CVD risk was found.

The association of gut microbiome composition with musculoskeletal features in middle-aged and older adults: a two-cohort joint study

Background

Bones and muscles are connected anatomically, and functionally. Preliminary evidence has shown the gut microbiome influences the aging process of bone and muscle in animal studies. However, such evidence in humans is still scarce. This study aimed to assess the microbiome-bone and microbiome-muscle associations in two cohorts of community-dwelling older adults.

Methods

We leveraged information from two large population-based cohorts, i.e., the Rotterdam Study (mean age 62.7 ± 5.6 years; n=1,249) and the Framingham Heart Study (mean age 55.2 ± 9.1 years; n=1,227). For individuals included in this study, gut microbiome 16S rRNA sequencing, musculoskeletal phenotyping derived from DXA images, lifestyle and socioeconomic data, and medication records were available. Per cohort, the 16S rRNA sequencing data, derived from stool, were processed with the DADA2 pipeline and taxonomies were assigned using the SILVA reference database. In addition, the microbiome functional potential was obtained with PICRUSt2. Further, we investigated the association between the human gut microbiome (alpha diversity, genera and predicted functional pathways) and appendicular lean mass (ALM), femoral neck bone mineral density (FN-BMD) and trabecular bone score (TBS) using multilinear regression models controlling for multiple confounders, and performed a joint analysis from both cohorts. Sex-stratified analyses were also conducted.

Results

The gut microbiome alpha diversity was not associated with either tested phenotype after accounting for multiple-testing (P>1.67e-02). In the joint analysis, lower abundance of Oscillibacter (beta= -.51, 95%CI [-0.74, -.29]), Anaerotruncus (beta=-0.41, 95%CI [-0.61, - 0.21]), Eisenbergiella (beta=-0.39, 95%CI [-0.59, -.19]) and higher abundance of Agathobacter (beta=0.40, 95%CI [0.20, 0.60]) were associated with higher ALM (P<2.0e-04). Lower abundance of Anaerotruncus (beta=-0.32, 95%CI [-0.45, -.19]), Hungatella (beta=-0.26, 95%CI [-0.38, -.15]) and Clostridiales bacterium DTU089 (beta=-0.37, 95%CI [-0.55, -.19]) was associated with higher ALM only in females (P< 2.0e-04). Moreover, the biotin biosynthesis II pathway was positively associated with ALM (beta=0.44, 95% CI [0.24, 0.64]) (P<1.90e-04) in females while no associations were observed in males. We did not observe any robust association of bone traits with gut microbiome features.

Conclusion

Our results indicate that specific genera are associated with ALM in middle-aged and older adults and these associations can present in a sex-specific manner. Overall, our study suggests that the gut microbiome is linked to muscle aging in middle-aged and older adults. However, larger sample sizes are still needed to underpin the specific microbiome features involved.

Liposome-Enabled Nanomaterials for Muscle Regeneration

Muscle regeneration is a vital biological process that is crucial for maintaining muscle function and integrity, particularly for the treatment of muscle diseases such as sarcopenia and muscular dystrophy. Generally, muscular tissues can self-repair and regenerate under various conditions, including acute or chronic injuries, aging, and genetic mutation. However, regeneration becomes challenging beyond a certain threshold, particularly in severe muscle injuries or progressive diseases. In recent years, liposome-based nanotechnologies have shown potential as promising therapeutic strategies for muscle regeneration. Liposomes offer an adaptable platform for targeted drug delivery due to their cell membrane-like structure and excellent biocompatibility. They can enhance drug solubility, stability, and targeted delivery while minimizing systemic side effects by different mechanisms. This review summarizes recent advancements, discusses current applications and mechanisms, and highlights challenges and future directions for possible clinical translation of liposome-based nanomaterials in the treatment of muscle diseases. It is hoped this review offers new insights into the development of liposome-enabled nanomedicine to address current limitations.