Effects of aging on muscle fibre type and size

Association of chair stand performance with all-cause and cardiovascular mortality in older adults with hypertension: A 28-country study

OBJECTIVE

To assess the prospective association of chair stand performance with all-cause and cardiovascular mortality in older adults with hypertension.

METHODS

From the Survey of Health, Ageing and Retirement in Europe (SHARE) study, we included 18,252 adults aged 50 years or more with hypertension from 28 countries (27 European countries and Israel). Chair stand performance was assessed by the time taken to complete five chair stands. We used time-varying Cox regression with restricted cubic splines to determine the prospective association of chair stand time with all-cause and cardiovascular mortality, controlling for various confounders.

KEY RESULTS

Over a mean follow-up of 3.5 years, 648 participants died, with 243 deaths attributed to cardiovascular disease. Using the median chair stand time (11 s) as a reference, both faster and slower times were associated with altered mortality risk in a curvilinear fashion. For all-cause mortality, the 10th percentile of chair stand time (7 s) showed a hazard ratio (HR) of 0.71 (95 % CI 0.60-0.85), while the 90th percentile (19 s) showed a HR of 1.20 (95 % CI 1.10-1.32). For cardiovascular mortality, the 10th percentile showed a subdistribution hazard ratio (SHR) of 0.72 (95 % CI 0.53-0.97), while the 90th percentile showed a SHR of 1.28 (95 % CI 1.10-1.48).

CONCLUSION

Chair stand performance is gradually and inversely associated with risk of all-cause and cardiovascular mortality in older adults with hypertension. These findings highlight the potential of the chair stand test as a prognostic measure.

Novel effects of reverse transcriptase inhibitor supplementation in skeletal muscle of old mice

Aging is the primary risk factor for the development of many chronic diseases, including dementias, cardiovascular disease, and diabetes. There is significant interest in identifying novel "geroprotective" agents, including by repurposing existing drugs, but such treatments may affect organ systems differently. One current example is the nucleoside reverse transcriptase inhibitor 3TC, which has been increasingly studied as a potential gerotherapeutic. Recent data suggest that 3TC may reduce inflammation and improve cognitive function in older mice; however, the effects of 3TC on other tissues in aged animals are less well characterized. Here, we use transcriptomics (RNA-seq) and targeted metabolomics to investigate the influence of 3TC supplementation on skeletal muscle in older mice. We show that 3TC 1) does not overtly affect muscle mass or functional/health markers, 2) largely reverses age-related changes in gene expression and metabolite signatures, and 3) is potentially beneficial for mitochondrial function in old animals via increases in antioxidant enzymes and decreases in mitochondrial reactive oxygen species. Collectively, our results suggest that, in addition to its protective effects in other tissues, 3TC supplementation does not have adverse effects in aged muscle and may even protect muscle/mitochondrial health in this context.NEW & NOTEWORTHY Recent studies suggest that the nucleoside reverse transcriptase inhibitor 3TC may improve brain health and cognitive function in old mice, but its effects on other aging tissues have not been comprehensively studied. This is the first study to use a multiomics approach to investigate the effects of 3TC treatment on skeletal muscle of old mice. The results suggest that 3TC reverses age-related transcriptomic and metabolite signatures and is potentially beneficial for mitochondrial function in aged muscle.

Combined effect of skeletal muscle mass loss and elevated insulin resistance on heart failure risk in older adults: a community-based longitudinal cohort study

BACKGROUND

Skeletal muscle mass loss and insulin resistance (IR) are associated with cardiovascular diseases risk. However, it remains unclear whether the combination of skeletal muscle mass loss and elevated IR affects heart failure (HF) risk. Here, we investigate the association between a combination of appendicular skeletal muscle mass index (ASMI) with estimated glucose disposal rate (eGDR) and HF risk in older adults.

METHODS

A prospective analysis and a dual-trajectory analysis were carried out to investigate the association of the combined effect of ASMI and eGDR with HF risk. A total of 11,596 adults aged ≥ 60 years were enrolled from the community for prospective analysis. Among them, 10,489 were eligible for the dual-trajectory analysis. The temporal evolution of ASMI and eGDR was determined using a dual-trajectory model.

RESULTS

In the prospective analysis, 1087 individuals developed HF. Restricted cubic splines analysis showed L-shaped associations between ASMI and eGDR and HF risk. HF risk decreased by 32.3% (hazard ratio (HR): 0.677, 95% confidence interval (CI): 0.623-0.734, Padj < 0.001) for female and 9.0% (HR 0.910, 95% CI 0.831-0.996, Padj = 0.003) for male patients per one standard deviation (SD) AMSI increment and 29.4% (HR 0.706, 95% CI 0.647-0.770, Padj < 0.001) for female and 26.8% (HR 0.732, 95% CI 0.668-0.803, Padj < 0.001) for male patients per one SD eGDR increment. There was a synergistic effect on HF risk per one SD ASMI and eGDR increment (Padj < 0.001). Five distinct dual ASMI and eGDR trajectories were identified in the dual-trajectory analysis. A total of 859 (8.85 per 1000 person-years) individuals developed HF. Compared to group 4 with moderate-stable ASMI and eGDR and the lowest incident HF, the HR in group 5 characterized by low-stable ASMI and eGDR was 1.908 (95% CI 1.482-2.457, Padj < 0.001), followed by 1.716 (95% CI 1.296-2.273, Padj < 0.001) in group 3 with low-decrease ASMI and high-decrease eGDR.

CONCLUSIONS

Skeletal muscle mass loss and elevated IR act synergistically to increase the HF risk in older adults. Comprehensive management of muscle mass and IR might be a useful and effective strategy for preventing and controlling HF.

TRIAL REGISTRATION

Retrospectively registered number ChiCTREOC17013598.

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.

Change in physical activity and the risk of depressive symptoms in mid-older aged adults

AIM

Middle-age and older adults' physical activity participation changes may influence their depressive conditions. This study explores the associations between changes in physical activity levels over time and the likelihood of depressive symptoms based on a population-based survey.

METHODS

This study included adults aged ≥50 years from the Taiwan Longitudinal Study in Aging (TLSA) survey. Physical activity levels from the 2003 and 2007 surveys were used to identify patterns of change across time. Multiple logistic regression was performed to examine the associations between changes in physical activity and the risk of depressive symptoms. Additional analyses were conducted to assess if the associations of change patterns varied by individuals' baseline physical activity levels.

RESULTS

Of the 3439 participants, 12.9% newly developed a high risk of depression over 4 years. Compared with those with constant physical activity levels, adults with decreased physical activity levels showed a significantly higher risk of depressive symptoms at follow-up (odds ratio = 1.59, 95% confidence interval: 1.23-2.06). The deteriorative association was most pronounced among individuals who had high physical activity levels at baseline but later reduced their activity (odds ratio = 2.01, 95% confidence interval: 1.48-2.72) compared with those who kept highly active. No significant association was observed among individuals who reported increased physical activity during the study period.

CONCLUSION

These findings highlight the importance of middle-aged and older adults staying physically active and avoiding reducing physical activity levels to prevent depression. Geriatr Gerontol Int 2025; ••: ••-••.

Effects of aging on calcium channels in skeletal muscle

In skeletal muscle, calcium is not only essential to stimulate and sustain their contractions but also for muscle embryogenesis, regeneration, energy production in mitochondria, and fusion. Different ion channels contribute to achieving the various functions of calcium in skeletal muscles. Muscle contraction is initiated by releasing calcium from the sarcoplasmic reticulum through the ryanodine receptor channels gated mechanically by four dihydropyridine receptors of T-tubules. The calcium influx through store-operated calcium channels sustains the contraction and stimulates muscle regeneration. Mitochondrial calcium uniporter allows the calcium entry into mitochondria to stimulate oxidative phosphorylation. Aging alters the expression and activity of these different calcium channels, resulting in a reduction of skeletal muscle force generation and regeneration capacity. Regular physical training and bioactive molecules from nutrients can prevent the effects of aging on calcium channels. This review focuses on the current knowledge of the effects of aging on skeletal muscles' calcium channels.

Combined exercise-induced modulation of Notch pathway and muscle quality in senescence-accelerated mice

The Notch signaling pathway is crucial for skeletal muscle development, regeneration, inflammation, and aging. This study investigated the association between interleukin-10 (IL-10) and the Notch pathway in C2C12 cells, as well as explored the effects of combined endurance and resistance exercise on the Notch and autophagy pathways in the skeletal muscle of senescence-accelerated mouse-resistant 1 Sedentary (SAMR1 CT), SAMR1 exercised (SAMR1 EX), senescence-accelerated prone mouse 8 Sedentary (SAMP8 CT), and SAMP8 exercised (SAMP8 EX). C2C12 myoblasts were transfected with siIL-10. Histological analysis, reverse transcription-quantitative polymerase chain reaction, and immunoblotting were performed on the quadriceps and tibialis anterior muscles. A publicly available dataset was analyzed to assess the Notch pathway in older men. In summary, IL-10 knockdown in myoblasts reduced the Notch pathway gene and protein expression. In SAMP8 mice, combined exercise improved muscle fiber organization, enhanced balance and coordination, and increased Notch2 and Hes1 mRNA levels. NOTCH2 mRNA levels were also higher in older men compared to young subjects with similar physical activity levels. These findings suggest that combined physical exercise enhances muscle regeneration via the Notch pathway in aged muscle.

Dietary influence on the link between depression and muscle mass and muscle strength: exploring interaction and mediation effects

INTRODUCTION

The present study aimed to investigate the associations of depression with muscle mass and muscle strength, and whether these associations were modified or mediated by dietary energy intake and dietary quality.

METHODS

Our study included participants aged 40 and above from the 2011-2018 cycles of the National Health and Nutrition Examination Survey (NHANES). Depression was evaluated using the nine-item Patient Health Questionnaire. Skeletal muscle mass index (SMI) and handgrip strength (HGS) were used to evaluate muscle mass and muscle strength, respectively. Information on dietary intake were obtained via dietary recall. Dietary quality was assessed using healthy eating index-2015 (HEI-2015). We performed multivariable linear regression models to examine the associations of depression with SMI (N = 3,648) and HGS (N = 4,679). Interaction analyses and mediation analyses were conducted to test the effect of dietary energy intake and HEI-2015 on the associations of depression with SMI and HGS.

RESULTS

Depression was associated with decreased SMI and HGS. Interactions between depression and HEI-2015 were observed for SMI, but not for HGS. The stratified analyses showed that depression was associated with decreased SMI in participants whose HEI-2015 were lower than the median. Mediation analyses revealed that dietary energy intake mediated the associations of depression with SMI and HGS.

CONCLUSION

HEI-2015 modified the associations between depression and muscle mass. The inverse associations of depression with muscle mass and muscle strength were partially mediated by dietary energy intake. These findings emphasized the importance of dietary energy intake and dietary quality in preventing muscle loss in middle-aged and older participants with depression.

Changes in motor unit firing pattern are associated with post-exercise blood pressure response in older untreated but not treated hypertensive adults

This study aimed to determine the difference in motor unit (MU) firing pattern between hypertensive and normotensive individuals, and the relationship between MU firing pattern and post-exercise blood pressure (BP) response in older individuals. Fourteen older untreated (systolic/diastolic BP (SBP/DBP) ≥ 130/80 mmHg, 76 (5) years), 11 treated hypertensive (78 (4) years) and 14 normotensive (SBP/DBP < 130/80 mmHg, 71 (4) years) individuals were studied. Participants performed ramp-up exercises until 50% of maximal voluntary contraction (MVC) of knee extension and five MVCs. During the ramp-up exercise, high-density surface electromyography signals were recorded and each MU firing rate (FR) and recruitment threshold was assessed. The slope of the linear regression between MUFRs and recruitment thresholds was calculated to assess the MU firing pattern. Pre- and post-exercise blood pressure was measured. Change in (∆)SBP from pre- to post-exercise was greater in treated hypertensive than untreated hypertensive individuals (P = 0.026). MUFR was lower in treated hypertensive than untreated hypertensive and normotensive individuals (P < 0.001). Although the slope was not significantly different between groups (P = 0.294), FRs of larger MUs were lower than those of smaller MUs in treated hypertensive and normotensive individuals (P < 0.05) but sustained in untreated hypertensive individuals. The FRs of larger MUs and slope were positively correlated with the ∆SBP only in hypertensive individuals (r = 0.768 and 0.715; P = 0.044 and 0.020). MUFR was lower in treated hypertensive than untreated hypertensive and normotensive individuals. Furthermore, MU firing patterns were associated with the ∆SBP after exercise in older untreated hypertensive individuals, but this relationship was not observed in treated hypertensive and normotensive individuals.

The link between Mitochondria and Sarcopenia

Sarcopenia, a widespread condition, is characterized by a variety of factors influencing its development. The causes of sarcopenia differ depending on the age of the individual. It is defined as the combination of decreased muscle mass and impaired muscle function, primarily observed in association with ageing. As people age from 20 to 80 years old, there is an approximate 30% reduction in muscle mass and a 20% decline in cross-sectional area. This decline is attributed to a decrease in the size and number of muscle fibres. The regression of muscle mass and strength increases the risk of fractures, frailty, reduced quality of life, and loss of independence. Muscle cells, fibres, and tissues shrink, resulting in diminished muscle power, volume, and strength in major muscle groups. One prominent theory of cellular ageing posits a strong positive relationship between age and oxidative damage. Heightened oxidative stress leads to early-onset sarcopenia, characterized by neuromuscular innervation breakdown, muscle atrophy, and dysfunctional mitochondrial muscles. Ageing muscles generate more reactive oxygen species (ROS), and experience decreased oxygen consumption and ATP synthesis compared to younger muscles. Additionally, changes in mitochondrial protein interactions, cristae structure, and networks may contribute to ADP insensitivity, which ultimately leads to sarcopenia. Within this framework, this review provides a comprehensive summary of our current understanding of the role of mitochondria in sarcopenia and other muscle degenerative diseases, highlighting the crucial need for further research in these areas.

Creatinine production rate is an integrative indicator to monitor muscle status in critically ill patients

BACKGROUND

Both quantitative and qualitative aspects of muscle status significantly impact clinical outcomes in critically ill patients. Comprehensive monitoring of baseline muscle status and its changes is crucial for risk stratification and management optimization. However, repeatable and accessible indicators are lacking. We hypothesized that creatinine production rate (CPR) could serve as an integrative indicator of skeletal muscle status.

METHODS

We conducted a series of animal and clinical studies. First, animal experiments were performed to determine whether CPR reflects not only muscle volume, but also qualitative muscle properties. We also evaluated the effects of acute systemic inflammation, a common feature of critical illness, on CPR, as well as its impact on muscle volume and metabolism. In clinical studies, we analyzed CPR, calculated based on urinary creatinine excretion and changes in serum creatinine, of critically ill patients. We assessed the factors affecting CPR on ICU admission and its temporal changes. Finally, we evaluated the clinical utility of CPR by examining the associations of the CPR index (CPR divided by height squared) on ICU admission and its changes with one-year survival.

RESULTS

Animal studies revealed that CPR is determined by muscle volume, creatine content, and metabolic status. Systemic inflammation accompanied by muscle loss led to reduced CPR. Moreover, even without muscle loss, systemic inflammation decreased CPR, likely due to metabolic derangements. In ICU patients, CPR on admission strongly correlated with muscle cross-sectional area (CSA), with age and sex as additional significant factors. In contrast, the percent change in CPR showed a weak correlation with muscle CSA changes. Additionally, the acute-phase CPR trajectories did not show a consistent decline, suggesting multifactorial influences. In a cohort of 629 ICU patients, lower baseline CPR index (hazard ratio [HR] 1.125 per 0.1 g/day/m2 less, P < .001) and a decrease in CPR over the first three days (HR 1.028 per 5%, P = 0.032) were independently associated with higher one-year mortality.

CONCLUSIONS

CPR represents an integrative indicator of skeletal muscle status in critically ill patients, reflecting both quantitative and qualitative aspects. Monitoring CPR in the ICU may facilitate risk stratification and optimization of patient care.

Oncological impact of the preoperative combined assessment of skeletal muscle mass for patients undergoing curative gastrectomy for gastric cancer

PURPOSE

We performed a combined assessment of skeletal muscle mass using the skeletal muscle mass index (SMI) and the psoas muscle index (PMI) to evaluate their association with the overall survival (OS) of gastric cancer patients after curative gastrectomy.

METHODS

We analyzed, retrospectively, the computed tomography records of skeletal muscle mass of patients who underwent radical gastrectomy for pStage I-III gastric cancer between April, 2010 and April, 2016. We then compared OS as the primary outcome, stratifying patients according to their SMI or PMI, and investigated prognostic factors using multivariate analyses.

RESULTS

The median follow-up duration was 62 months. Of the 550 patients analyzed, 262 (47.6%), 194 (35.3%), and 94 (17.1%) were classified into normal, single-low, and double-low SMI and PMI groups, respectively. Patients with double-low SMI and PMI had the poorest OS (P = 0.018). Multivariate analysis revealed that double-low indices were an independent prognostic factor for poor OS (hazard ratio, 1.808; 95% confidence interval 1.009-3.238; P = 0.046).

CONCLUSIONS

This study revealed that evaluation of skeletal muscle mass based on the combined SMI and PMI can predict the survival outcomes of patients after curative gastrectomy for gastric cancer, and that the coexistence of a low-SMI and low-PMI was associated with the poorest survival.

Factors, mechanisms and improvement methods of muscle strength loss

Muscle strength is a crucial aspect of muscle function, essential for maintaining normal physical activity and quality of life. The global aging population coupled with the increasing prevalence of muscle disorders and strength loss, poses a remarkable public health challenge. Understanding the mechanisms behind muscle strength decline is vital for improving public health outcomes. This review discusses recent research advancements on muscle strength loss from various perspectives, including factors contributing to muscle strength decline, the signaling pathways involved in the deterioration of muscle function, and the methods for assessing muscle strength. The final section explores the influence of exercise stimulation and nutrition on muscle strength.

Correlation between Phase Angle and the Number of Medications in Older Inpatients: A Cross-Sectional Study

BACKGROUND

Muscle weakness in older adults elevates mortality risk and impairs quality of life, with the phase angle (PhA) indicating cellular health. Polypharmacy, common in geriatric care, could influence PhA. This investigates whether the number of medications and polypharmacy with PhA as a biomarker of muscle quality in older inpatients aged ≥65 and determines the extent to which multiple medications contribute to the risk of reduced muscle quality.

METHODS

This retrospective cross-sectional study analyzed data from older inpatients requiring rehabilitation. PhA was measured using bioelectrical impedance analysis. The number of medications taken by each patient was recorded at admission. Polypharmacy was defined as the concurrent use of five or more medications at admission.

RESULTS

In this study of 517 hospitalized older adults (median age 75 years; 47.4% men), 178 patients (34.4%) were diagnosed with sarcopenia. Polypharmacy was present in 66% of patients. The median PhA was 4.9° in men and 4.3° in women. Multivariate linear regression analysis was performed separately for men and women. In men, PhA was negatively correlated with the number of medications (β=-0.104, p=0.041) and polypharmacy (β=-0.045, p=0.383). In women, PhA was negatively correlated with the number of medications (β=-0.119, p=0.026) and polypharmacy (β=-0.098, p=0.063). Analyses were adjusted for age, body mass index, sarcopenia, C-reactive protein, and hemoglobin levels.

CONCLUSION

The number of medications at admission negatively impacted PhA in older inpatients, highlighting the importance of reviewing prescribed drugs and their interactions.

Sarcopenia Is a Prognostic Factor of Adverse Effects and Mortality in Patients With Tumour: A Systematic Review and Meta-Analysis

BACKGROUND

The relationship between sarcopenia and the prognosis of patients with tumours who received radio- and/or chemotherapy still needs to be determined. In this study, we aim to investigate the relationship between sarcopenia and adverse effects and mortality in patients with tumours that received radio- and/or chemotherapy, stratified by study design, tumour category, the method sarcopenia assessed, treatment options, study location and among other factors.

METHODS

PubMed, Web of Science and Embase were searched from inception to 15 August 2024, without language restrictions and with a manual search of references for additional articles retrieval. Cohort studies of ≥ 100 patients with tumours that evaluated the association between sarcopenia or muscle mass and the adverse effects or overall survival induced by radio- and/or chemotherapy were included.

RESULTS

Thirty-nine studies were included, involving 8966 patients with tumours, including 3383 patients with sarcopenia. The pooled prevalence of sarcopenia in patients with tumours was 0.42 (95% CI 0.36-0.48, p < 0.001) overall. The prevalence of sarcopenia is higher in Oceania patients 0.60 (95% CI 0.28-0.89, p < 0.001), those with reproductive tumour 0.57 (95% CI 0.30-0.83, p < 0.001), and sarcopenia assessed by the lumbar-skeletal muscle index 0.46 (95% CI 0.39-0.53, p < 0.001) than in other subgroups, but not show significant differences in sex. Sarcopenia was associated with an increased risk of adverse effects in patients who received radio- and/or chemotherapy, with a relative risk (RR) of 1.44 (95% CI 1.21-1.71, p < 0.001). Retrospective studies (RR = 1.49; 95% CI 1.24-1.79; p < 0.001), sarcopenia assessed by other methods (RR = 2.98; 95% CI 1.52-5.87; p < 0.001), and patients in Europe (RR = 1.92; 95% CI 1.15-3.22; p = 0.013), received chemoradiotherapy (RR = 1.47; 95% CI 1.23-1.76; p < 0.001), and with head and neck tumours (RR = 1.54; 95% CI 1.17-2.01; p = 0.010) had higher relative risk than other subgroups. Sarcopenia was also associated with reduced overall survival in patients with tumours, with a pooled hazard ratio (HR) of 1.66 (95% CI 1.40-1.96, p < 0.001). Prospective studies (HR = 1.72; 95% CI 0.97-3.07; p = 0.065), sarcopenia assessed by the cervical-skeletal muscle index (HR = 2.66; 95% CI 1.73-4.09; p < 0.001), and patients in Asia (HR = 1.91; 95% CI 1.50-2.42; p < 0.001), received chemoradiotherapy (HR = 1.85; 95% CI 1.46-2.45; p < 0.001) and with head and neck tumours (HR = 2.35; 95% CI 1.88-2.95; p < 0.001) had higher HR than other subgroups.

CONCLUSIONS

Sarcopenia was associated with a higher risk of adverse effects and mortality in patients with tumours received radio- and/or chemotherapy.

Aging-associated differences between perioral and trunk muscle characteristics

The physiological and functional changes from aging affect the systemic and swallowing muscles. While ultrasound is used to examine muscle characteristics, no previous studies have examined the relationship between age and perioral and trunk muscle characteristics, including stiffness. This study aimed to investigate the relationship between age and the characteristics of perioral and trunk muscles, including quality, quantity, and stiffness, using ultrasound. A total of 215 participants were recruited for this cross-sectional study: 98 younger adults (20-64 years) and 117 older adults (≥ 65 years). Muscle characteristics were assessed along with data on age, sex, body mass index, and number of teeth. The correlation between age and muscle characteristics was examined. Multiple linear regression was performed with muscle characteristics as dependent variables and age, body mass index, and number of teeth as explanatory variables. We found that only trunk muscle stiffness was associated with age, with a stronger correlation in quality and quantity than perioral muscles. Masseter muscle quality and quantity showed a higher correlation with age than those of the geniohyoid muscle. In conclusion, characteristics of the trunk and perioral muscles exhibit differences in age-related changes, highlighting the importance of maintaining both trunk and perioral muscle activity in older adults to prevent functional decline.

Prevalence and risk factors for sarcopenia in active community-dwelling older adults according to the EWGSOP2 criteria

The prevalence of sarcopenia depends on the diagnostic criteria and updates used. There are few studies investigating the relationship between the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria and risk factors in active community-dwelling older adults. In this cross-sectional study, a total of 533 community-dwelling active older adults were assessed. 3.75 % were diagnosed with confirmed sarcopenia and 15.86 % with probable sarcopenia. The risk of sarcopenia was found to increase with age, taking more than four tablets a day and having a low level of education. There is a possible association between smoking and living alone. In contrast, active older adults had a lower prevalence of sarcopenia compared to the European and global populations, suggesting a protective effect of physical activity adherence against sarcopenia. Further studies in this population are needed to increase the sample size and to better understand the development and factors associated with sarcopenia.

Lifelong dietary protein restriction induces denervation and skeletal muscle atrophy in mice

As a widespread global issue, protein deficiency hinders development and optimal growth in offspring. Maternal low-protein diet influences the development of age-related diseases, including sarcopenia, by altering the epigenome and organ structure through potential increase in oxidative stress. However, the long-term effects of lactational protein restriction or postnatal lifelong protein restriction on the neuromuscular system have yet to be elucidated. Our results demonstrated that feeding a normal protein diet after lactational protein restriction did not have significant impacts on the neuromuscular system in later life. In contrast, a lifelong low-protein diet induced a denervation phenotype and led to demyelination in the sciatic nerve, along with an increase in the number of centralised nuclei and in the gene expression of atrogenes at 18 months of age, indicating an induced skeletal muscle atrophy. These changes were accompanied by an increase in proteasome activity in skeletal muscle, with no significant alterations in oxidative stress or mitochondrial dynamics markers in skeletal muscle later in life. Thus, lifelong protein restriction may induce skeletal muscle atrophy through changes in peripheral nerves and neuromuscular junctions, potentially contributing to the early onset or exaggeration of sarcopenia.

Relationship between histological findings of vastus lateralis muscle and function after total hip arthroplasty in patients with hip fracture: a prospective cohort study

BACKGROUND AND PURPOSE

 We aimed to examine the histological characteristics of vastus lateralis muscles in patients undergoing total hip arthroplasty (THA) following femoral neck fractures and to explore the correlation between muscle fiber types and postoperative functional recovery.

METHODS

 34 patients undergoing THA for femoral neck fractures were included. A biopsy of the vastus lateralis muscle was performed during surgery, followed by immunohistochemical staining. Subsequently, image analysis was conducted to measure the average area of muscle fiber types and the number of type I and II muscle fibers, and the ratio of the area and the number of type II muscle fibers. Functional recovery was assessed 2 weeks post-surgery using the Short Physical Performance Battery (SPPB).

RESULTS

A significant positive correlation was observed between type II muscle fibers and SPPB scores. The ratio of type II muscle fiber area and number strongly correlated with the SPPB scores, indicating a robust static association. The average area of type II fibers showed a strong correlation (r = 0.63, P < 0.001), as did the number of type II fibers (r = 0.53, P = 0.001). Moreover, the ratio of type II muscle fiber area and number significantly correlated with SPPB scores (area: r = 0.77, P < 0.001; number: r = 0.51, P = 0.002), indicating that larger and more numerous type II fibers are associated with better physical performance.

CONCLUSION

The reduction of type II muscle fibers was strongly correlated with a low SPPB postoperative functional recovery in patients who underwent THA following femoral neck fractures.

Association Between Depressive Symptoms, Cognitive Status, and the Dual-Task Performance Index in Older Adults: A Cross-Sectional Study

The Performance Index (P-Index) is a measure for evaluating mobility-related dual-task performance in older adults. The identification of specific clinicodemographic factors predictive of P-Index scores, however, remains unclear. This cross-sectional study analyzed data from 120 community-dwelling older adults (average age 71.3 ± 11.23 years) to explore clinicodemographic variables that influence P-Index scores during the instrumented timed up and go test. Unadjusted analyses suggested several factors, including age, gender, body mass index, Mini-Mental Status Examination scores, functional reach test performance, history of falls, ethnicity, Geriatric Depression Scale scores, alcohol consumption, and educational levels, as potential predictors of P-Index. However, adjusted multinomial multiple regression analysis revealed Geriatric Depression Scale and Mini-Mental Status Examination scores as the exclusive independent predictors of P-Index classifications, segmented into high, intermediate, or low (percentiles ≤ 25, 26-74, or ≥ 75, respectively). A significant association was observed between the manifestation of depressive symptoms, lower Mini-Mental Status Examination scores, and reduced cognitive-motor performance. The findings implicate depressive symptoms and low cognitive performance as substantial impediments to optimal dual-task mobility within this cohort. Further studies are warranted to examine the efficacy of cognitive stimulation and antidepressant therapy, in augmenting mobility-related dual-task performance among older adults.

Effects of Lumbar Stabilization on Scapular Muscle Activity, Activation Onset Time, and Kinematics in Individuals with Scapular Dyskinesis

This study aimed to investigate the effects of lumbar stabilization on muscle activity, muscle onset time, and scapular kinematics in individuals with scapular dyskinesis. Fourteen participants with scapular dyskinesis were recruited. Scapular muscle activity and activation onset time were measured by electromyography (EMG), and scapular upward rotation was measured by two-dimensional (2-D) Kinovia software, under two conditions: with and without abdominal bracing. There was a significant increase in the activity of the serratus anterior, middle trapezius, and inferior trapezius muscles between the conditions (p < 0.001, p = 0.045, and p < 0.001, respectively). During abdominal bracing, the activation onset time of the serratus anterior and lower trapezius was noticeably shorter (p = 0.041 and p = 0.011, respectively). Scapular upward rotation at 30°, 60°, 90°, and 120° of shoulder abduction was significantly greater (p = 0.027, p = 0.003, p = 0.003, and p = 0.030, respectively). Increased scapular muscle activation, early activation onset time, and increased scapular upward rotation were also noted. These changes have an impact on the scapulohumeral rhythm.

Gui Qi Zhuang Jin Decoction ameliorates mitochondrial dysfunction in sarcopenia mice via AMPK/PGC-1α/Nrf2 axis revealed by a metabolomics approach

OBJECTIVE

Sarcopenia, as a condition of muscle mass loss and functional decline typically diagnosed in elderly individuals, severely affects human physical activity, metabolic homeostasis, and quality of life. Gui Qi Zhuang Jin Decoction (GQZJD), an approved hospital-based prescription with years of clinical application, has been demonstrated to have a notable therapeutic effect on sarcopenia. However, its potential mechanism of action in the treatment of sarcopenia remains uncertain.

METHODS

Ultra-performance liquid chromatography paired with Q Exactive™ HF-X mass spectrometry (UPLC-QE-MS) was used to identify the ingredients of GQZJD. Subsequently, GQZJD observed the basic growth and muscles of the sarcopenia mouse, while the behavioral indicators were also tested. Muscle histopathology and serum oxidative stress biochemicals were also detected, and mitochondrial function and energy metabolism-related indicators in the gastrocnemius muscle were examined. Then, a metabolomics strategy was applied to predict possible pathways involving mitochondria by which GQZJD could improve sarcopenia. Finally, quantitative real-time polymerase chain reaction and western blot analyses were carried out to validate the effects of GQZJD on sarcopenia-induced mitochondrial dysfunction, together with uncovering the associated mechanisms.

RESULTS

Twenty-seven ingredients absorbed into the blood (IAIBs) of GQZJD were identified using UPLC-QE-MS, which were regarded as the main active ingredients behind its sarcopenia treatment effects. GQZJD administration increased the body weight, gastrocnemius muscle mass, and autonomic activity, mitigated muscle tissue morphology and pathology; and alleviated the oxidative stress levels in sarcopenia mice. Treatment with GQZJD also decreased the mitochondrial reactive oxygen species level and serum lipid peroxide Malonaldehyde concentration. and increased the mitochondrial membrane potential, adenosine triphosphate level, 8‑hydroxy-2-deoxyguanosine content, mitochondrial DNA copy number, and the mitochondrial fission factor dynamin-related protein 1. Non-targeted metabolomics suggested that the sarcopenia therapeutic effect of GQZJD on sarcopenia may occur through the glycerophospholipid metabolism, choline metabolism in cancer, phenylalanine metabolism and tyrosine metabolism pathways, implying an association with AMP-activated protein kinase (AMPK) and related signals. Further, the molecular docking results hinted that AMPK performed well in terms of binding energy with the 27 IAIBs of GQZJD (average binding energy, -7.5 kcal/mol). Finally, we determined that GQZJD significantly activated the key targets of the AMPK/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis..

CONCLUSIONS

Our results demonstrated that GQZJD ameliorated d-galactose-induced sarcopenia by promoting the animal behaviours, facilitating mitochondrial function and restoring mitochondrial energy metabolism. with its effects mediated by the AMPK/PGC-1α/Nrf2 axis. Over all, GQZJD represents a promising therapeutic candidate that ameliorated sarcopenia in aging mice.

Which Sit-to-Stand Test Best Differentiates Functional Capacity in Older People?

ABSTRACT

The sit-to-stand test provides insight into age-related functional capacity; however, there are various variants of sit-to-stand, and we do not know which of these better discriminates against age-related functional capacity. Our study aimed to compare the age-related functional capacity in older people by evaluating sit-to-stand power variants, using young individuals as a reference. A cross-sectional study was conducted in 102 adults (57 women) aged 60-80 and 105 adults (54 women) aged 20-30. Participants performed five times sit-to-stand (5 sit-to-stand), 30-second sit-to-stand, and 1-min sit-to-stand. Z scores were obtained for each sit-to-stand variant using power (W), relative (W/kg), and allometric (W/m 2 ) normalization methods. A mixed repeated-measures analysis of variance assessed the interactions among the sit-to-stand variants, normalization methods, sex, physical activity, and tobacco history. A significant interaction between sit-to-stand variants, normalization methods, and sex ( P = 0.002) was found. The mean effect of sit-to-stand variants revealed that the 1-min sit-to-stand had the lowest Z score ( P < 0.05). Significant variations were observed between sit-to-stand variants in all normalization methods for women ( P < 0.001). However, in men, only the difference between 5 sit-to-stand and 1-min sit-to-stand remained consistent across normalization methods ( P < 0.05). Our findings highlight the efficacy of 1-min sit-to-stand in distinguishing age-related functional capacity over the other sit-to-stand tests, especially in women.

Acute effect of an intervention with open and closed kinetic chain muscle strength exercises on postural control and muscle power in elderly people: A randomized clinical trial

INTRODUCTION

Aging causes changes in stance control and muscle function. However, strength exercises can mitigate these negative effects. Intervention practices are classified into open kinetic chain (OKC) and closed kinetic chain (CKC), but it is unclear whether there are differences between them regarding muscle power and balance in the older people. Thus, this study aimed to investigate the acute effect of an intervention in OKC and CKC on stance control and muscle power in the older people.

METHODS

This study is a randomized clinical trial. A total of 29 older people participated in this study, divided into 3 groups: control group (CG) (n = 9), open kinetic chain group (OKCG) (n = 10), and closed kinetic chain group (CKCG) (n = 10). Stance control was evaluated on a force platform under bipedal, semi-tandem, and unipedal support conditions. Muscle power assessed based on the time to perform the sit-to-stand test (STS). The acute intervention in OKC and CKC consisted of 2 exercises for each intervention group.

RESULTS

There was no difference between acute interventions in OKC and CKC on stance control and muscle power. The time in STS was shorter in the CKCG compared to the CG. The largest oscillations of the center of pressure (COP) were found in the unipedal stance condition.

CONCLUSION

An acute intervention in OKC and CKC did not differentiate stance balance and muscle power in the older people. However, CKC exercises are more effective for functional tasks than OKC exercises. The greater complexity of the task (unipedal support) causes greater stance oscillations in the older people.

Endurance exercise-induced histone methylation modification involved in skeletal muscle fiber type transition and mitochondrial biogenesis

Skeletal muscle is a highly heterogeneous tissue, and its contractile proteins are composed of different isoforms, forming various types of muscle fiber, each of which has its own metabolic characteristics. It has been demonstrated that endurance exercise induces the transition of muscle fibers from fast-twitch to slow-twitch muscle fiber type. Herein, we discover a novel epigenetic mechanism for muscle contractile property tightly coupled to its metabolic capacity during muscle fiber type transition with exercise training. Our results show that an 8-week endurance exercise induces histone methylation remodeling of PGC-1α and myosin heavy chain (MHC) isoforms in the rat gastrocnemius muscle, accompanied by increased mitochondrial biogenesis and an elevated ratio of slow-twitch to fast-twitch fibers. Furthermore, to verify the roles of reactive oxygen species (ROS) and AMPK in exercise-regulated epigenetic modifications and muscle fiber type transitions, mouse C2C12 myotubes were used. It was shown that rotenone activates ROS/AMPK pathway and histone methylation enzymes, which then promote mitochondrial biogenesis and MHC slow isoform expression. Mitoquinone (MitoQ) partially blocking rotenone-treated model confirms the role of ROS in coupling mitochondrial biogenesis with muscle fiber type. In conclusion, endurance exercise couples mitochondrial biogenesis with MHC slow isoform by remodeling histone methylation, which in turn promotes the transition of fast-twitch to slow-twitch muscle fibers. The ROS/AMPK pathway may be involved in the regulation of histone methylation enzymes by endurance exercise.

Effect of Lactational Low-Protein Diet on Skeletal Muscle during Adulthood and Ageing in Male and Female Mouse Offspring

Sarcopenia is characterised by the loss of skeletal muscle mass and function, which leads to a high risk of increased morbidity and mortality. Maternal malnutrition has been linked to impaired development of skeletal muscle of the offspring; however, there are limited studies that report the long-term effect of a maternal low-protein diet during lactation on the ageing of skeletal muscles. This study aimed to examine how a maternal low-protein diet (LPD) during lactation affects skeletal muscle ageing in the offspring. Pups born from control mothers were lactated by mothers fed with an LPD. Post-weaning, mice were either maintained on an LPD or switched to a control, normal-protein diet (NPD). In males, an LPD mainly affected the size of the myofibres without a major effect on fibre number and led to reduced grip strength in ageing mice (24 months). Female mice from mothers on an LPD had a lower body and muscle weight at weaning but caught up with control mice at 3 months. During ageing, the muscle weight, myofibre number and survival rate of female pups were significantly affected. These findings highlight the effect of an LPD during lactation on skeletal muscle ageing, the lifespan of offspring and the importance of sexual dimorphism in response to dietary challenges.

Athletic Performance Decline Over the Life Span: Cross-Sectional and Longitudinal Analyses of Elite and Masters Track-and-Field Data

PURPOSE

Loss of muscle power has a significant impact on mobility in geriatric populations, so this study sought to determine the extent and time course of performance decline in power-centric events throughout the life span via retrospective analyses of masters and elite track-and-field data.

METHODS

Four track-and-field events were selected based on maximal power output: the 100-m dash, long jump, high jump, and triple jump. Elite and masters athlete data were gathered from the World Masters Outdoor Championships and the International Amateur Athletic Federation World Athletics Championships (17,945 individual results). Data were analyzed by fitting individual and group results to quadratic and linear models.

RESULTS

Average age of peak performance in all events was 27.8 (0.8) years for men and 28.3 (0.8) years for women. Athlete performance decline best matched a linear model for the 5 years following peak performance (mean R2 = .68 [.20]) and for ages 35-60, but best matched a quadratic model for ages 60-90 and 35-90 (mean R2 = .75 [.12]). The average rate of decline for the masters data ages 35-60 ranged from 0.55% per year for men's 100-m dash to 1.04% per year for women's long jump. A significant age × sex interaction existed between men and women, with men declining faster throughout life in all events except the 100-m dash.

CONCLUSIONS

Performance decline begins in the early 30s and is linear through middle age. This pattern of decline provides a basis for further research on power-decline pathophysiology and preventive measures starting in the 30s.

Skeletal muscle dysfunction with advancing age

As a result of advances in medical treatments and associated policy over the last century, life expectancy has risen substantially and continues to increase globally. However, the disconnect between lifespan and 'health span' (the length of time spent in a healthy, disease-free state) has also increased, with skeletal muscle being a substantial contributor to this. Biological ageing is accompanied by declines in both skeletal muscle mass and function, termed sarcopenia. The mechanisms underpinning sarcopenia are multifactorial and are known to include marked alterations in muscle protein turnover and adaptations to the neural input to muscle. However, to date, the relative contribution of each factor remains largely unexplored. Specifically, muscle protein synthetic responses to key anabolic stimuli are blunted with advancing age, whilst alterations to neural components, spanning from the motor cortex and motoneuron excitability to the neuromuscular junction, may explain the greater magnitude of function losses when compared with mass. The consequences of these losses can be devastating for individuals, their support networks, and healthcare services; with clear detrimental impacts on both clinical (e.g., mortality, frailty, and post-treatment complications) and societal (e.g., independence maintenance) outcomes. Whether declines in muscle quantity and quality are an inevitable component of ageing remains to be completely understood. Nevertheless, strategies to mitigate these declines are of vital importance to improve the health span of older adults. This review aims to provide an overview of the declines in skeletal muscle mass and function with advancing age, describes the wide-ranging implications of these declines, and finally suggests strategies to mitigate them, including the merits of emerging pharmaceutical agents.

Mouse sarcopenia model reveals sex- and age-specific differences in phenotypic and molecular characteristics

Our study was to characterize sarcopenia in C57BL/6J mice using a clinically relevant definition to investigate the underlying molecular mechanisms. Aged male (23-32 months old) and female (27-28 months old) C57BL/6J mice were classified as non-, probable-, or sarcopenic based on assessments of grip strength, muscle mass, and treadmill running time, using 2 SDs below the mean of their young counterparts as cutoff points. A 9%-22% prevalence of sarcopenia was identified in 23-26 month-old male mice, with more severe age-related declines in muscle function than mass. Females aged 27-28 months showed fewer sarcopenic but more probable cases compared with the males. As sarcopenia progressed, a decrease in muscle contractility and a trend toward lower type IIB fiber size were observed in males. Mitochondrial biogenesis, oxidative capacity, and AMPK-autophagy signaling decreased as sarcopenia progressed in males, with pathways linked to mitochondrial metabolism positively correlated with muscle mass. No age- or sarcopenia-related changes were observed in mitochondrial biogenesis, OXPHOS complexes, AMPK signaling, mitophagy, or atrogenes in females. Our results highlight the different trajectories of age-related declines in muscle mass and function, providing insights into sex-dependent molecular changes associated with sarcopenia progression, which may inform the future development of novel therapeutic interventions.

Prognostic Value of New Sarcopenia Screening Tool in the Elderly-SARC-GLOBAL

Sarcopenia screening tools have a low capacity to predict adverse outcomes that are consequences of sarcopenia in the elderly population. This study aimed to evaluate the ability of a new sarcopenia screening tool SARC-GLOBAL to predict negative clinical outcomes in the elderly. A total of 395 individuals were evaluated in a 42-month period. The screening tools SARC-GLOBAL, SARC-F, and SARC-CalF and the diagnosis of sarcopenia according to European Working Group on Sarcopenia in Older Persons (EWGSOP2) were performed at the beginning of the study. Logistic and Poisson regression models were applied to assess the predictive value of the tools for the odds and risks of negative clinical outcomes, respectively. The most common negative clinical outcome in the followed population was falls (12.9%), followed by infections (12.4%), hospitalizations (11.8%), fractures (4.3%), and deaths (2.7%). Both SARC-GLOBAL and SARC-F were similar in predicting the odds of falls and hospitalizations during the follow up period, however SARC-CalF only predicted the odds of hospitalizations at 42 months.

Body Composition and Its Interaction with Bone Mineral Density and Biochemical and Nutritional Parameters in Chilean Adults with Overweight/Obesity and Normal Weight

This study aimed to compare and relate the body composition (obtained through anthropometry with the pentacompartmental model and the tricompartmental model by DXA) with bone mineral density and biochemical and nutritional parameters in Chilean adults with overweight/obesity and normal weight from La Araucanía region, Chile. A case-control study was conducted with 116 adults and volunteers from the PURE cohort, collecting sociodemographic data, BMI assessment, waist-to-hip ratio (WHR), and body composition using the pentacompartmental model (5CM) and tricompartmental model (3CM) by DXA, as well as bone mineral density (BMD). Blood biochemical parameters (fasting glucose and lipid profile), physical activity (PA) measured by GPAQ, and average dietary habits (R24h) were measured. In the overweight/obesity group, the 5CM and 3CM adipose mass were indirectly and moderately correlated with PA (p < 0.05), except in the male 5CM group. In the overweight/obesity group, muscle and fat-free mass (FFM) of the 5CM and 3CM correlated directly and moderately with blood fasting glucose (BFG) and BMD (p < 0.05), except in females, where FFM was not related to BMD but was related to residual mass (p < 0.01). Independent of gender and BMI, bone mineral content was positively and highly correlated with BMD (p < 0.0000). In the male overweight/obesity group, bone, skin, and residual mass were correlated with BFG (p < 0.05). In conclusion, for the assessment of non-athletic adult populations, more routine use of the 5CM in clinical practice is recommended.

Combined Nutrition with Exercise: Fueling the Fight Against Sarcopenia Through a Bibliometric Analysis and Review

Objective

This bibliometric analysis and review aimed to examine the current research status and trends in the combination of nutrition and exercise training for sarcopenia. Additionally, it sought to provide researchers with future research directions in this field.

Methods

Relevant publications were obtained from the Web of Science Core Collection (WoSCC) database, covering the period from January 1995 to October 2023. The collected publications were analyzed using CiteSpace, VOSviewer, Bibliometrix, and Review Manager.

Results

Out of the 2528 retrieved publications, the United States emerged as the leading contributor in terms of publication volume. The University of Texas System was identified as the most productive institution. Luc J C van Loon emerged as the most published author in this field. Analysis of keywords revealed recent hot topics and emerging areas of interest, such as "gut microbiota" and "mechanisms". Upon further evaluation, resistance training (RT) and protein supplementation were identified as the most commonly employed and effective methods.

Conclusion

RT and protein supplementation are widely recognized as effective strategies. Future research should focus on investigating the molecular aspects of sarcopenia. Moreover, the potential therapeutic role of gut microbiota in sarcopenia requires further comprehensive investigation in human subjects to establish its correlation.

Impact of Chinese herbal medicine on sarcopenia in enhancing muscle mass, strength, and function: A systematic review and meta-analysis of randomized controlled trials

Sarcopenia has become important to the public health with the increase in the aging population in society. However, the therapeutic effects of conventional approaches, including pharmacotherapy, exercise, and nutritional intervention, are far from satisfactory. Chinese herbal medicine is a new treatment format with interesting possibilities in sarcopenia has been widely practiced. The study aims to explore the effectiveness of Chinese herbal medicine in sarcopenia. We comprehensively searched the following electronic databases: Medline, EMBASE, APA PsycInfo, Cochrane Library, Web of Science, PubMed, and Chinese database from the establishment of the database to December 2022 (no language restrictions). Randomized controlled clinical studies on the use of Chinese herbal medicine in sarcopenia were selected in compliance with PRISMA guidelines. Review Manager and Stata were used for statistical analysis and the mean difference and standardized mean difference were adopted. Of 277 identified studies, 17 were eligible and included in our analysis (N = 1440 participants). The results showed that Chinese herbal medicine can improve total efficiency (RR = 1.29, 95% CI [1.21, 1.36], p < 0.00001) in sarcopenia and enhance muscle mass (SMD = 1.02, 95% CI [0.55, 1.50], p < 0.0001), and muscle strength measured by grip strength (SMD = 0.66, 95% CI [0.36, 0.96], p < 0.0001), measured by 60°/s knee extension peak TQ (MD = 5.63, 95% CI [-0.30, 11.57], p = 0.06) and muscle function measured by 6-meter walking speed (SMD = 1.34, 95% CI [0.60, 2.08], p = 0.0004), measured by the short physical performance battery of 1.50%, 95% CI (1.05, 1.95), measured by the EuroQoL 5-dimension of (SMD = 0.27, 95% CI [-0.10, 0.65], p = 0.16), suggesting that Chinese herbal medicine alone or combined with conventional treatment has ameliorating effect on sarcopenia. Chinese herbal medicine is a potential therapeutic strategy in sarcopenia. The funnel plot and Egger's test indicated publication bias. To confirm our conclusions, further high-quality studies should be conducted.

Dynamic changes in butyrate levels regulate satellite cell homeostasis by preventing spontaneous activation during aging

The gut microbiota plays a pivotal role in systemic metabolic processes and in particular functions, such as developing and preserving the skeletal muscle system. However, the interplay between gut microbiota/metabolites and the regulation of satellite cell (SC) homeostasis, particularly during aging, remains elusive. We propose that gut microbiota and its metabolites modulate SC physiology and homeostasis throughout skeletal muscle development, regeneration, and aging process. Our investigation reveals that microbial dysbiosis manipulated by either antibiotic treatment or fecal microbiota transplantation from aged to adult mice, leads to the activation of SCs or a significant reduction in the total number. Furthermore, employing multi-omics (e.g., RNA-seq, 16S rRNA gene sequencing, and metabolomics) and bioinformatic analysis, we demonstrate that the reduced butyrate levels, alongside the gut microbial dysbiosis, could be the primary factor contributing to the reduction in the number of SCs and subsequent impairments during skeletal muscle aging. Meanwhile, butyrate supplementation can mitigate the antibiotics-induced SC activation irrespective of gut microbiota, potentially by inhibiting the proliferation and differentiation of SCs/myoblasts. The butyrate effect is likely facilitated through the monocarboxylate transporter 1 (Mct1), a lactate transporter enriched on membranes of SCs and myoblasts. As a result, butyrate could serve as an alternative strategy to enhance SC homeostasis and function during skeletal muscle aging. Our findings shed light on the potential application of microbial metabolites in maintaining SC homeostasis and preventing skeletal muscle aging.

Advances in sarcopenia: mechanisms, therapeutic targets, and intervention strategies

Sarcopenia is a multifactorial condition characterized by loss of muscle mass. It poses significant health risks in older adults worldwide. Both pharmacological and non-pharmacological approaches are reported to address this disease. Certain dietary patterns, such as adequate energy intake and essential amino acids, have shown positive outcomes in preserving muscle function. Various medications, including myostatin inhibitors, growth hormones, and activin type II receptor inhibitors, have been evaluated for their effectiveness in managing sarcopenia. However, it is important to consider the variable efficacy and potential side effects associated with these treatments. There are currently no drugs approved by the Food and Drug Administration for sarcopenia. The ongoing research aims to develop more effective strategies in the future. Our review of research on disease mechanisms and drug development will be a valuable contribution to future research endeavors.

Synergistically Acting on Myostatin and Agrin Pathways Increases Neuromuscular Junction Stability and Endurance in Old Mice

Sarcopenia is the primary cause of impaired motor performance in the elderly. The current prevailing approach to counteract such condition is increasing the muscle mass through inhibition of the myostatin system: however, this strategy only moderately improves muscular strength, not being able to sustain the innervation of the hypertrophic muscle per se, leading to a progressive worsening of motor performances. Thus, we proposed the administration of ActR-Fc-nLG3, a protein that combines the soluble activin receptor, a strong myostatin inhibitor, with the C-terminal agrin nLG3 domain. This compound has the potential of reinforcing neuro-muscular stability to the hypertrophic muscle. We previously demonstrated an enhancement of motor endurance and ACh receptor aggregation in young mice after ActR-Fc-nLG3 administration. Now we extended these observations by demonstrating that also in aged (2 years-old) mice, long-term administration of ActR-Fc-nLG3 increases in a sustained way both motor endurance and muscle strength, compared with ActR-Fc, a myostatin inhibitor, alone. Histological data demonstrate that the administration of this biological improves neuromuscular stability and fiber innervation maintenance, preventing muscle fiber atrophy and inducing only moderate hypertrophy. Moreover, at the postsynaptic site we observe an increased folding in the soleplate, a likely anatomical substrate for improved neurotransmission efficiency in the NMJ, that may lead to enhanced motor endurance. We suggest that ActR-Fc-nLG3 may become a valid option for treating sarcopenia and possibly other disorders of striatal muscles.

Metabolic signatures and potential biomarkers of sarcopenia in suburb-dwelling older Chinese: based on untargeted GC-MS and LC-MS

BACKGROUND

Untargeted metabolomics can be used to expand our understanding of the pathogenesis of sarcopenia. However, the metabolic signatures of sarcopenia patients have not been thoroughly investigated. Herein, we explored metabolites associated with sarcopenia by untargeted gas chromatography (GC)/liquid chromatography (LC)-mass spectrometry (MS) and identified possible diagnostic markers.

METHODS

Forty-eight elderly subjects with sarcopenia were age and sex matched with 48 elderly subjects without sarcopenia. We first used untargeted GC/LC-MS to analyze the plasma of these participants and then combined it with a large number of multivariate statistical analyses to analyze the data. Finally, based on a multidimensional analysis of the metabolites, the most critical metabolites were considered to be biomarkers of sarcopenia.

RESULTS

According to variable importance in the project (VIP > 1) and the p-value of t-test (p < 0.05), a total of 55 metabolites by GC-MS and 85 metabolites by LC-MS were identified between sarcopenia subjects and normal controls, and these were mostly lipids and lipid-like molecules. Among the top 20 metabolites, seven phosphatidylcholines, seven lysophosphatidylcholines (LysoPCs), phosphatidylinositol, sphingomyelin, palmitamide, L-2-amino-3-oxobutanoic acid, and palmitic acid were downregulated in the sarcopenia group; only ethylamine was upregulated. Among that, three metabolites of LysoPC(17:0), L-2-amino-3-oxobutanoic acid, and palmitic acid showed very good prediction capacity with AUCs of 0.887 (95% CI = 0.817-0.957), 0.836 (95% CI = 0.751-0.921), and 0.805 (95% CI = 0.717-0.893), respectively.

CONCLUSIONS

These findings show that metabonomic analysis has great potential to be applied to sarcopenia. The identified metabolites could be potential biomarkers and could be used to study sarcopenia pathomechanisms.

Protective Effect of Whole Wheat on Muscle Atrophy in C2C12 Cells via Akt/FoxO1 Signaling Pathways

Skeletal muscles are important for body movement, postural maintenance, and energy metabolism. Muscle atrophy is caused by various factors, including lack of exercise, age, genetics, and malnutrition, leading to the loss of muscle mass. The Akt/FoxO signaling pathway plays a key role in the regulation of muscle protein synthesis and degradation. Whole wheat contains functional ingredients that may indirectly contribute to muscle health and function and can help prevent or slow the progression of muscle atrophy. In this study, the protective effects of three wheat cultivars (Seodun, Ol, and Shinmichal 1) against hydrogen peroxide-induced muscle atrophy in C2C12 cells were investigated. We found that whole-wheat treatment reduced reactive oxygen species production, prevented glutathione depletion, and increased myotube diameter, thereby reducing muscle atrophy by activating myoblast differentiation. Generally, "Shinmichal 1" exhibited the highest activation of the Akt/FoxO signaling pathway. In contrast, "Seodun" showed similar or slightly higher activities than those of the H2O2-treated only group. In conclusion, whole wheat exerts a protective effect against muscle atrophy by activating the Akt/FoxO signaling pathway. This study indicates that whole wheat may help prevent muscle atrophy.

The Effects of Aging on Sarcoplasmic Reticulum-Related Factors in the Skeletal Muscle of Mice

The pathogenesis of sarcopenia includes the dysfunction of calcium homeostasis associated with the sarcoplasmic reticulum; however, the localization in sarcoplasmic reticulum-related factors and differences by myofiber type remain unclear. Here, we investigated the effects of aging on sarcoplasmic reticulum-related factors in the soleus (slow-twitch) and gastrocnemius (fast-twitch) muscles of 3- and 24-month-old male C57BL/6J mice. There were no notable differences in the skeletal muscle weight of these 3- and 24-month-old mice. The expression of Atp2a1, Atp2a2, Sln, and Pln increased with age in the gastrocnemius muscles, but not in the soleus muscles. Subsequently, immunohistochemical analysis revealed ectopic sarcoplasmic reticulum calcium ion ATPase (SERCA) 1 and SERCA2a immunoreactivity only in the gastrocnemius muscles of old mice. Histochemical and transmission electron microscope analysis identified tubular aggregate (TA), an aggregation of the sarcoplasmic reticulum, in the gastrocnemius muscles of old mice. Dihydropyridine receptor α1, ryanodine receptor 1, junctophilin (JPH) 1, and JPH2, which contribute to sarcoplasmic reticulum function, were also localized in or around the TA. Furthermore, JPH1 and JPH2 co-localized with matrix metalloproteinase (MMP) 2 around the TA. These results suggest that sarcoplasmic reticulum-related factors are localized in or around TAs that occur in fast-twitch muscle with aging, but some of them might be degraded by MMP2.

Lifelong dietary protein restriction accelerates skeletal muscle loss and reduces muscle fibre size by impairing proteostasis and mitochondrial homeostasis

The early life environment significantly affects the development of age-related skeletal muscle disorders. However, the long-term effects of lactational protein restriction on skeletal muscle are still poorly defined. Our study revealed that male mice nursed by dams fed a low-protein diet during lactation exhibited skeletal muscle growth restriction. This was associated with a dysregulation in the expression levels of genes related to the ribosome, mitochondria and skeletal muscle development. We reported that lifelong protein restriction accelerated loss of type-IIa muscle fibres and reduced muscle fibre size by impairing mitochondrial homeostasis and proteostasis at 18 months of age. However, feeding a normal-protein diet following lactational protein restriction prevented accelerated fibre loss and fibre size reduction in later life. These findings provide novel insight into the mechanisms by which lactational protein restriction hinders skeletal muscle growth and includes evidence that lifelong dietary protein restriction accelerated skeletal muscle loss in later life.

Effect of different postures and loads on joint motion and muscle activity in older adults during overhead retrieval

Introduction: Pain is a common health problem among older adults worldwide. Older adults tend to suffer from arm, lumbar, and back pain when using hanging cabinets. Methods: This study used surface electromyography to record muscle activity and a motion capture system to record joint motion to research effects of different loads and retrieval postures on muscle activity and joint range of motion when older adults retrieve objects from a high place, to provide optimised feedback for the design of hanging cabinet furniture. Results: We found that: 1) The activity of BB (Biceps brachii) on the side of the body interacting with the cabinet door was greater than that of UT (Upper trapezius) and BR (Brachial radius) when retrieving objects from a high place, the activity of UT on the side of the body interacting with a heavy object was greater than that of BB and BR. 2) The activity of UT decreases when the shoulder joint angle is greater than 90°, but the activity of BB increases as the angle increases. In contrast, increasing the object's mass causes the maximum load on the shoulder joint. 3) Among the different postures for overhead retrieval, alternating between the right and left hand is preferable for the overhead retrieval task. 4) Age had the most significant effect on overhead retrieval, followed by height (of person), and load changes were significantly different only at the experiment's left elbow joint and the L.BR. 5) Older adults took longer and exerted more effort to complete the task than younger adults, and static exercise in older adults may be more demanding on muscle activity in old age than powered exercise. Conclusion: These results help to optimise the design of hanging cabinet furniture. Regarding the height of hanging cabinets, 180 cm or less is required for regular retrieval movements if the human height is less than 150 cm. Concerning the depth of the hanging cabinets, different heights chose different comfort distances, which translated into the depth of the hanging cabinets; the greater the height, the greater the depth of the hanging cabinets to use.

Leveraging Biomaterial Platforms to Study Aging-Related Neural and Muscular Degeneration

Aging is a complex multifactorial process that results in tissue function impairment across the whole organism. One of the common consequences of this process is the loss of muscle mass and the associated decline in muscle function, known as sarcopenia. Aging also presents with an increased risk of developing other pathological conditions such as neurodegeneration. Muscular and neuronal degeneration cause mobility issues and cognitive impairment, hence having a major impact on the quality of life of the older population. The development of novel therapies that can ameliorate the effects of aging is currently hindered by our limited knowledge of the underlying mechanisms and the use of models that fail to recapitulate the structure and composition of the cell microenvironment. The emergence of bioengineering techniques based on the use of biomimetic materials and biofabrication methods has opened the possibility of generating 3D models of muscular and nervous tissues that better mimic the native extracellular matrix. These platforms are particularly advantageous for drug testing and mechanistic studies. In this review, we discuss the developments made in the creation of 3D models of aging-related neuronal and muscular degeneration and we provide a perspective on the future directions for the field.

Differences in acute neuromuscular response after single session of resistance exercise between young and older adults

AIMS

The purpose of this study was to investigate differences in the acute response after resistance exercise between young and older adults.

METHODS

Seventeen young and 18 older adults performed a single session of resistance exercise, consisting of 3 sets of 10 isometric knee extensions. Maximal voluntary contraction (MVC), motor unit (MU) activity of the vastus lateralis, and electrically elicited torque of the knee extensor were measured before and after the resistance exercise.

RESULTS

Although both groups showed the same degree of decline in MVC (young: -15.2 ± 14.3 %, older: -16.4 ± 7.9 %, p = 0.839), electrically elicited torque markedly decreased in the young group (young: -21.5 ± 7.7 %, older: -14.3 ± 9.5 %, p < 0.001), and the decrease in the MU firing rate was greater in the older group (young: -26.1 ± 24.1 %, older: -44.7 ± 24.5 %, p < 0.001). Changes in the MU firing rate following the exercise were correlated with the MU recruitment threshold in the older group (p < 0.001, rs = 0.457), but not young group (p = 0.960).

DISCUSSION

These results showed that young adults exhibited a greater acute response in the peripheral component, whereas older adults showed a greater acute response in the central component of the neuromuscular system, and the acute response in MUs with a high recruitment threshold following resistance exercise was smaller than in those with a low recruitment threshold in older adults. These findings may partly explain why there are different chronic adaptations to resistance training between young and older adults.

Exercise is associated with younger methylome and transcriptome profiles in human skeletal muscle

Exercise training prevents age-related decline in muscle function. Targeting epigenetic aging is a promising actionable mechanism and late-life exercise mitigates epigenetic aging in rodent muscle. Whether exercise training can decelerate, or reverse epigenetic aging in humans is unknown. Here, we performed a powerful meta-analysis of the methylome and transcriptome of an unprecedented number of human skeletal muscle samples (n = 3176). We show that: (1) individuals with higher baseline aerobic fitness have younger epigenetic and transcriptomic profiles, (2) exercise training leads to significant shifts of epigenetic and transcriptomic patterns toward a younger profile, and (3) muscle disuse "ages" the transcriptome. Higher fitness levels were associated with attenuated differential methylation and transcription during aging. Furthermore, both epigenetic and transcriptomic profiles shifted toward a younger state after exercise training interventions, while the transcriptome shifted toward an older state after forced muscle disuse. We demonstrate that exercise training targets many of the age-related transcripts and DNA methylation loci to maintain younger methylome and transcriptome profiles, specifically in genes related to muscle structure, metabolism, and mitochondrial function. Our comprehensive analysis will inform future studies aiming to identify the best combination of therapeutics and exercise regimes to optimize longevity.

Age-related changes and sex differences in ankle plantarflexion velocity

Ankle plantar flexors play a vital role in the mobility of older adults. The strength and velocity of plantarflexion are critical factors in determining walking speed. Despite reports on how age and sex affect plantarflexion strength, basic information regarding plantarflexion velocity is still lacking. This cross-sectional observational study investigated age-related changes and sex differences in plantarflexion velocity by comparing them with plantarflexion strength. A total of 550 healthy adults were classified into four age groups for each sex: Young (< 40 years old), Middle-aged (40-64 years old), Young-old (65-74 years old), and Older-old (≧ 75 years old). We measured plantarflexion velocity and strength in the long-sitting position using a gyroscope and a hand-held dynamometer, respectively. Two-way analysis of variance revealed no interaction between age and sex for either plantarflexion velocity or strength. Plantarflexion velocity exhibited a significant decline with aging, as did the plantarflexion strength. We found no significant sex differences in plantarflexion velocity in contrast to plantarflexion strength. The results indicated a significant decrease with age and no difference in plantarflexion velocity between males and females characteristic plantarflexion velocity. Understanding the characteristics of plantarflexion velocity could contribute to preventing a decline in mobility in older adults.

Between-sexes differences in lumbopelvic muscle mechanical properties of non-climacteric adults: a cross-sectional design

The lumbopelvic muscle mechanical properties (MMPs) are clinically relevant, but their dependence on sex remains unknown. Therefore, this study aimed to identify if lumbopelvic MMPs depend on the sex in a young adult population. Thirty-five healthy nulliparous women and 35 healthy men were analyzed (age range: 18-50). Lumbopelvic MMPs, that is, tone, stiffness, elasticity, relaxation and creep, assessed with MyotonPRO®, and pelvic floor (PF) health questionnaires were compared between-sexes. Intra-group correlations between sociodemographic and clinical data, and MMPs were also determined. The MMPs of PF were different between healthy non-climacteric adults of both sexes, with women showing higher values of tone and stiffness and lower values of elasticity and viscoelastic properties than men (in all cases, p < 0.03). At lumbar level, tone and stiffness were higher for men at both sides (in all cases, p < 0.04), and relaxation was lower at left side (p = 0.02). The MMPs showed few correlations with sociodemographic data within women. However, within males, there were positive correlations for PF stiffness and viscoelastic parameters with age, BMI and function (0.334 < r < 0.591) and, at lumbar level, negative correlations for tone and stiffness ( - 0.385 < r < -0.590) and positive correlations for viscoelastic properties (0.564 < r < 0.719), with BMI. This indicated that between-sexes differences of lumbopelvic MMPs depend on the specific location of assessment in healthy non-obese young individuals. Women show higher tone and stiffness and lower elasticity and viscoelasticity than men, at PF level.

Sex Differences in the Association of Weight-Adjusted-Waist Index with Sarcopenic Obesity: A Cross-Sectional Study of Hemodialysis Patients

Objective: To explore the association between weight-adjusted-waist index (WWI) and sarcopenic obesity (SO) in patients with maintenance hemodialysis (MHD). Methods: A multicenter, cross-sectional study that included 3311 adult MHD patients was conducted in 20 hemodialysis (HD) centers from June 1, 2021, to August 30, 2021. Body composition was evaluated by body composition monitor based on bioimpedance spectroscopy. Hand grip strength was measured by CAMRY® dynamometer. WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Multiple logistic regression models, spearman correlation analysis, and receiver-operating characteristic (ROC) analyses were conducted. Results: The median age of the study was 55 years, and 39.4% of patients were female. The prevalence of SO was 22.7% in the total population, and patients with SO had higher WWI. Higher WWI quartiles were independently associated with a higher risk of SO in men after adjusting for potential confounders, including age, dialysis vintage, body mass index, biochemical indicators, and various medical histories; the odds ratio (OR) of SO was highest in the fourth quartile of the WWI (OR: 4.08, 95% confidence interval: 2.65-6.27, P for trend <0.001). Age-adjusted WWI provided a better diagnostic power than WWI only for SO in men (area under the ROC curve: 0.72 vs. 0.68, P < 0.001). WWI was not associated with SO in female HD patients. Conclusion: WWI is independently associated with SO in male but not female MHD patients. This anthropometric index is simple to calculate, making it applicable in clinical practice.

Functional and emotional impact of COVID-19 lockdown on older adults with sarcopenia living in a nursing home: A 15-month follow-up

This study aimed to detect the functional and emotional impact of COVID-19 lockdown on institutionalized older adults with sarcopenia during a 15-month follow-up. A prospective longitudinal cohort study was conducted in a nursing home. Participants were screened for sarcopenia, and those with a score of ≥4 points according to SARC-F questionnaire were included. Assessments were performed pre-lockdown (T1), 12 months (T2) after, and at a 15-month follow-up (T3). Functional measurements included chair stand test, handgrip, biceps brachii and quadriceps femoris strengths, appendicular skeletal mass, gait speed, Short Physical Performance Battery, and Timed Up-and-Go test. Emotional assessments included Short-Form Health Survey, Geriatric Depression Scale-Short Form, and the Mini-Mental State Examination. The analyzed sample showed a reduction in bicep strength, and other upper and lower limb strength variables showed a decreasing trend with no changes regarding muscle mass. Physical performance showed a change, specifically a deterioration in the subtest related to balance. Cognitive and emotional components were affected and quality of life was decreased. It is of paramount importance to focus on sarcopenic older adults since their characteristics can deteriorate when isolation measures are conducted.

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.

Comparing neuromotor functions in 45- and 65-year-old adults with 18-year-old adolescents

Aim

This cross-sectional analysis investigates how neuromotor functions of two independent cohorts of approximately 45- and 65-year-old individuals are different from 18-year-old adolescents using the Zurich Neuromotor Assessment-2 (ZNA-2).

Methods

A total of 186 individuals of the Zurich Longitudinal Studies (ZLS) born in the 1950s (mean age 65.1 years, SD = 1.2 year, range of ages 59.0-67.5 years, n = 151, 82 males) and 1970s (mean age 43.6 years, SD = 1.3 year, range of ages 40.8-46.6 years, n = 35, 16 males) were tested with the ZNA-2 on 14 motor tasks combined in 5 motor components: fine motor, pure motor, balance, gross motor, and associated movements. Motor performance measures were converted into standard deviation scores (SDSs) using the normative data for 18-year-old individuals as reference.

Results

The motor performance of the 45-year-old individuals was remarkably similar to that of the 18-year-olds (SDS from -0.22 to 0.25) apart from associated movements (-0.49 SDS). The 65-year-olds showed lower performance than the 18-year-olds in all components of the ZNA-2, with the smallest difference observed for associated movements (-0.67 SDS) and the largest for gross motor skills (-2.29 SDS). Higher body mass index (BMI) was associated with better performance on gross motor skills for 45-year-olds but with worse performance for 65-year-olds. More educational years had positive effects on gross motor skills for both ages.

Interpretation

With the exception of associated movements, neuromotor functions as measured with the ZNA-2 are very similar in 45- and 18-year-olds. In contrast, at age 65 years, all neuromotor components show significantly lower function than the norm population at 18 years. Some evidence was found for the last-in-first-out hypothesis: the functions that developed later during adolescence, associated movements and gross motor skills, were the most vulnerable to age-related decline.