Sarcopenia Is Recognized as an Independent Condition by an International Classification of Disease, Tenth Revision, Clinical Modification (ICD-10-CM) Code

Association between sarcopenic obesity and knee osteoarthritis: A narrative review

Sarcopenia and obesity have been studied independently as risk factors for knee osteoarthritis. However, there is now research interest in investigating whether the co-existence of sarcopenia and obesity (sarcopenic obesity) within the same individual significantly increases the risk of knee osteoarthritis, compared to sarcopenia or obesity alone. This review synthesises current literature to explore the association between sarcopenic obesity and knee osteoarthritis, emphasising both the clinical evidence and existing gaps. We highlight the challenges and progress in defining sarcopenic obesity and discuss the impact that the lack of a consensus definition of sarcopenic obesity has on comparing outcomes of studies investigating the relationship between sarcopenic obesity and knee OA. We offer methodological insights to guide future studies investigating whether sarcopenic obesity increases the risk of knee osteoarthritis above and beyond the risk associated with each condition on its own. The implications for clinical practice are discussed, including the need to incorporate effective resistance exercise into weight loss programs for individuals with sarcopenic obesity. This is critical as a general weight loss program alone among individuals with sarcopenic obesity can include substantial loss of muscle mass, potentially predisposing patients to further functional decline.

Comprehensive assessment and treatment strategies for dysphagia in the elderly population: Current status and prospects

As the population ages, the prevalence of dysphagia among older adults is a growing concern. Age-related declines in physiological function, coupled with neurological disorders and structural changes in the pharynx associated with aging, can result in weakened tongue propulsion, a prolonged reaction time of the submental muscles, delayed closure of the laryngeal vestibule, and delayed opening of the upper esophageal sphincter (UES), increasing the risk of dysphagia. Dysphagia impacts the physical health of the elderly, leading to serious complications such as dehydration, aspiration pneumonia, malnutrition, and even life-threatening conditions, and it also detrimentally affects their psychological and social well-being. There is a significant correlation between frailty, sarcopenia, and dysphagia in the elderly population. Therefore, older adults should be screened for dysphagia to identify both frailty and sarcopenia. A reasonable diagnostic approach for dysphagia involves screening, clinical assessment, and instrumental diagnosis. In terms of treatment, multidisciplinary collaboration, rehabilitation training, and the utilization of new technologies are essential. Future research will continue to concentrate on these areas to enhance the diagnosis and treatment of dysphagia, with the ultimate aim of enhancing the quality of life of the elderly population.

Predictive value of sarcopenia components for all-cause mortality: findings from population-based cohorts

BACKGROUND

Low grip strength and gait speed are associated with mortality. However, investigation of the additional mortality risk explained by these measures, over and above other factors, is limited.

AIM

We examined whether grip strength and gait speed improve discriminative capacity for mortality over and above more readily obtainable clinical risk factors.

METHODS

Participants from the Health, Aging and Body Composition Study, Osteoporotic Fractures in Men Study, and the Hertfordshire Cohort Study were analysed. Appendicular lean mass (ALM) was ascertained using DXA; muscle strength by grip dynamometry; and usual gait speed over 2.4-6 m. Verified deaths were recorded. Associations between sarcopenia components and mortality were examined using Cox regression with cohort as a random effect; discriminative capacity was assessed using Harrell's Concordance Index (C-index).

RESULTS

Mean (SD) age of participants (n = 8362) was 73.8(5.1) years; 5231(62.6%) died during a median follow-up time of 13.3 years. Grip strength (hazard ratio (95% CI) per SD decrease: 1.14 (1.10,1.19)) and gait speed (1.21 (1.17,1.26)), but not ALM index (1.01 (0.95,1.06)), were associated with mortality in mutually-adjusted models after accounting for age, sex, BMI, smoking status, alcohol consumption, physical activity, ethnicity, education, history of fractures and falls, femoral neck bone mineral density (BMD), self-rated health, cognitive function and number of comorbidities. However, a model containing only age and sex as exposures gave a C-index (95% CI) of 0.65(0.64,0.66), which only increased to 0.67(0.67,0.68) after inclusion of grip strength and gait speed.

CONCLUSIONS

Grip strength and gait speed may generate only modest adjunctive risk information for mortality compared with other more readily obtainable risk factors.

Translatability of mouse muscle-aging for humans: the role of sex

Muscle-aging drives sarcopenia and is a major public health issue. Mice are frequently used as a model for human muscle-aging, however, research investigating their translational value is limited. In addition, mechanisms underlying muscle-aging may have sex-specific features in humans, but it is not yet assessed whether these are recapitulated in mice. Here, we studied the effects of aging on a functional, histological and transcriptional level at multiple timepoints in male and female mice (4, 17, 21 and 25 months), with particular emphasis on sex-differences. The effects of natural aging on the transcriptome of quadriceps muscle were compared to humans on pathway level. Significant loss of muscle mass occurred late, at 25 months, in both male (-17%, quadriceps) and female mice (-10%, quadriceps) compared to young control mice. Concomitantly, we found in female, but not male mice, a slower movement speed in the aged groups compared to the young mice (P < 0.001). Consistently, weighted gene co-expression network analysis revealed a stronger association between the aging-related reduction of movement and aging-related changes in muscle transcriptome of female compared to male mice (P < 0.001). In male, but not female mice, major distinctive aging-related changes occurred in the last age group (25 months), which highlights the necessity for careful selection of age using mice as a muscle-aging model. Furthermore, contrasting to humans, more aging-related changes were found in the muscle transcriptome of male mice compared to female mice (4090 vs. 2285 differentially expressed genes at 25 months, respectively). Subsequently, male mice recapitulated more muscle-aging related pathways characteristic for both male and female humans. In conclusion, our data show that sex has a critical effect on the mouse muscle-aging trajectory, although these do not necessarily reflect sex differences observed in the human muscle-aging trajectory.

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.

Sarcopenia in gynaecological cancers

Gynaecological cancers (GCs) comprise a group of cancers that originate in the female reproductive organs. Each GC is unique, with different signs and symptoms, risk factors and therapeutic strategies. Worldwide, the majority of GCs are still associated with high mortality rates, especially ovarian, due to difficulty in early detection. Despite numerous studies on the underlying pathophysiology, research in the field of GCs poses unique scientific and technological challenges. These challenges require a concerted multi- and inter-disciplinary effort by the clinical, scientific and research communities to accelerate the advancement of prognostic, diagnostic, and therapeutic approaches. Sarcopenia is a multifactorial disease which leads to the systemic loss of skeletal muscle mass and function. It can be caused by malignancies, as well as due to malnutrition, physical inactivity, ageing and neuromuscular, inflammatory, and/or endocrine diseases. Anorexia and systemic inflammation can shift the metabolic balance of patients with cancer cachexia towards catabolism of skeletal muscle, and hence sarcopenia. Therefore, sarcopenia is considered as an indicator of poor general health status, as well as the possible indicator of advanced cancer. There is a growing body of evidence showing the prognostic significance of sarcopenia in various cancers, including GCs. This review will outline the clinical importance of sarcopenia in patients with GCs.

The bidirectional relationship between sarcopenia and disability in China: a longitudinal study from CHARLS

Objectives

Sarcopenia and disability represent significant concerns impacting the health of older people. This study aimed to explore the bidirectional relationship between sarcopenia and disability in Chinese older people.

Methods

This study recruited older people ≥60 years old from the China Health and Retirement Longitudinal Study. In phase I, the study analyzed the relation between disability and subsequent sarcopenia using multinomial logistic regression models. Conversely, in phase II, the study assessed whether sarcopenia was associated with future disability using binary logistic regression models.

Results

In phase I, 65 (16.80%) new cases of possible sarcopenia, 18 (4.65%) cases of sarcopenia, and 9 (2.33%) cases of severe sarcopenia were observed in the disabled older people and 282 (10.96%) new cases of possible sarcopenia, 97 (3.77%) cases of sarcopenia, 35 (1.36%) cases of severe sarcopenia were observed in the older people without disability. The OR (95% CI) for sarcopenia in older disabled individuals compared to those without disability was 1.61 (1.25-2.07). Adjusting for all covariates in 2011, the OR (95% CI) value for disabled individuals vs. those without disability was 1.35 (1.02-1.79). Subgroup analyses showed that disabled participants aged < 80 years were more likely to have sarcopenia (OR = 1.42, 95% CI: 1.07-1.89), and the risk of sarcopenia did not differ significantly between sex subgroups. In phase II, 114 cases (33.83%) in the possible sarcopenia patients, 85 cases (28.91%) in the sarcopenia patients, 23 cases (35.94%) in the severe sarcopenia patients, and 501 cases (16.10%) in the individuals without sarcopenia showed symptoms of disability. The OR (95% CI) for disability was 2.66 (2.08-3.40) in the possible sarcopenia patients, 2.12 (1.62-2.77) in the sarcopenia patients, and 2.92 (1.74-4.91) in the severe sarcopenia patients compared with the no sarcopenia patients. After adjusting for all covariates in 2011, the OR (95% CI) values were 2.21 (1.70-2.85) in the possible sarcopenia patients, 1.58 (1.14-2.19) in the sarcopenia patients, and 1.99 (1.14-3.49) in the severe sarcopenia patients, as compared to the older people without sarcopenia. Subgroup analyses showed that compared with men, women with possible sarcopenia had a higher risk of disability (OR = 2.80, 95% CI: 1.98-3.97). In addition, participants aged < 80 years with sarcopenia or severe sarcopenia s were more likely to have disability (OR = 2.13, 95% CI: 1.52-2.98; OR = 2.98, 95% CI: 1.60-5.54).

Conclusion

The occurrence of disability increase the risk of sarcopenia in the older people, and baseline sarcopenia predicts the future disability in older people.

Three-Year Mortality of Older Hospitalized Patients with Osteosarcopenia: Data from the OsteoSys Study

Osteosarcopenia, the concurrent presence of sarcopenia and osteopenia/osteoporosis, poses a significant health risk to older adults, yet its impact on clinical outcomes is not fully understood. The aim of this prospective, longitudinal multicentre study was to examine the impact of osteosarcopenia on 3-year mortality and unplanned hospitalizations among 572 older hospitalized patients (mean age 75.1 ± 10.8 years, 78% female). Sarcopenia and low bone mineral density (BMD) were evaluated using Dual Energy X-ray Absorptiometry and the European Working Group on Sarcopenia in Older People (EWGSOP2) and WHO criteria, respectively. Among participants, 76% had low BMD, 9% were sarcopenic, and 8% had osteosarcopenia. Individuals with osteosarcopenia experienced a significantly higher rate of mortality (46%, p < 001) and unplanned hospitalization (86%, p < 001) compared to those without this condition. Moreover, "healthy" subjects-those without sarcopenia or low BMD-showed markedly lower 3-year mortality (9%, p < 001) and less unplanned hospitalization (53%, p < 001). The presence of osteosarcopenia (p = 0.009) increased the 3-year mortality risk by 30% over sarcopenia alone and by 8% over low BMD alone, underscoring the severe health implications of concurrent muscle and bone deterioration. This study highlights the substantial impact of osteosarcopenia on mortality among older adults, emphasizing the need for targeted diagnostic and therapeutic strategies.

Association between the Thickness or Area of the Temporal Muscle and Skeletal Muscle Mass in Bioimpedance Analysis

INTRODUCTION

Sarcopenia associated with stroke can significantly impact patient prognosis; however, the current standard diagnostic methods for sarcopenia are rarely used in stroke patients. Therefore, the aim of the current study was to investigate whether the temporal muscle thickness (TMT) or area (TMA) could serve as a surrogate marker for measuring skeletal muscle mass.

METHODS

This retrospective chart review study was conducted on 244 participants from March 2018 to February 2020. The TMT and TMA were measured at the supraorbital roof level using brain CT or T1-weighted MR imaging obtained from participants. The skeletal muscle mass and skeletal muscle index (SMI) and whole-body phase angle (WBPA) at 50 kHz were collected. Pearson correlation analysis was used to assess the relationship between the TMT or TMA and the results of the bioimpedance analysis.

RESULTS

The mean TMT showed significant positive correlations with skeletal muscle mass (male, r = 0.520; female, r = 0.706), SMI (male, r = 0.426; female, r = 0.582), and WBPA (male, r = 0.295; female, r = 0.232). The mean TMA showed significant positive correlations with skeletal muscle mass (male, r = 0.490; female, r = 0.657), SMI (male, r = 0.289; female, r = 0.473), and WBPA (male, r = 0.232; female, r = 0.243).

CONCLUSION

We observed moderate to strong positive correlations between body composition analysis measured by BIA and TMT or TMA, suggesting that TMT or TMA could serve as a reliable surrogate marker for identifying low skeletal muscle mass in cerebrovascular disease.

Iron status and sarcopenia-related traits: a bi-directional Mendelian randomization study

Although serum iron status and sarcopenia are closely linked, the presence of comprehensive evidence to establish a causal relationship between them remains insufficient. The objective of this study is to employ Mendelian randomization techniques to clarify the association between serum iron status and sarcopenia. We conducted a bi-directional Mendelian randomization (MR) analysis to investigate the potential causal relationship between iron status and sarcopenia. MR analyses were performed using inverse variance weighted (IVW), MR-Egger, and weighted median methods. Additionally, sensitivity analyses were conducted to verify the reliability of the causal association results. Then, we harvested a combination of SNPs as an integrated proxy for iron status to perform a MVMR analysis based on IVW MVMR model. UVMR analyses based on IVW method identified causal effect of ferritin on appendicular lean mass (ALM, β = - 0.051, 95% CI - 0.072, - 0.031, p = 7.325 × 10-07). Sensitivity analyses did not detect pleiotropic effects or result fluctuation by outlying SNPs in the effect estimates of four iron status on sarcopenia-related traits. After adjusting for PA, the analysis still revealed that each standard deviation higher genetically predicted ferritin was associated with lower ALM (β = - 0.054, 95% CI - 0.092, - 0.015, p = 0.006). Further, MVMR analyses determined a predominant role of ferritin (β = - 0.068, 95% CI - 0.12, - 0.017, p = 9.658 × 10-03) in the associations of iron status with ALM. Our study revealed a causal association between serum iron status and sarcopenia, with ferritin playing a key role in this relationship. These findings contribute to our understanding of the complex interplay between iron metabolism and muscle health.

Feasibility and preliminary effects of a mindfulness-based physical exercise (MBPE) program for community-dwelling older people with sarcopenia: A protocol for a parallel, two-armed pilot randomised controlled trial

INTRODUCTION

Physical exercise (PE) is essential for alleviating the symptoms of sarcopenia. Low motivation is a major barrier to PE. Mindfulness-based intervention (MBI) has the potential to improve motivation. However, few studies have used a mindfulness-based PE (MBPE) intervention among older people with sarcopenia.

OBJECTIVES

To assess the feasibility, acceptability and preliminary effects of the MBPE program among community-dwelling older people with sarcopenia.

METHODS AND ANALYSIS

A two-arm pilot randomised controlled trial will be conducted to assess the feasibility, acceptability and preliminary effects of an MBPE program among community-dwelling older people with sarcopenia. A total of 60 participants will be randomised into the intervention group, receiving the MBPE intervention twice a week over 12 weeks, or the control group, receiving health education with the same duration, number of sessions and frequency as the intervention group. Each session of the MBPE program will last about 60 min, including 5-10- min introduction, 20-min MBI, 30-min PE and 5-10-min sharing and discussion. The primary outcomes will be the feasibility (i.e., the time spent recruiting participants, the eligibility rate and the recruitment rate) and acceptability (i.e., the attendance rate, completion rate and attrition rate) of the MBPE program. The secondary outcomes will be the preliminary effects of the MBPE program on symptoms of sarcopenia, motivation for PE, psychological well-being, mindfulness level, physical activity level and quality of life. Individual interviews will be conducted to identify the strengths, limitations and therapeutic components of the intervention. The quantitative data will be analysed by generalised estimating equations. The qualitative data will be analysed by Braun and Clarke's thematic approach.

CONCLUSION

The findings of this study will be able to provide evidence for the health professionals in adopting MBPE as a supportive intervention for the older adults with sarcopenia and the groundworks for the researchers in developing non-pharmacological intervention for older adults. The positive effects could facilitate healthy ageing and relief the burden of the medical system, especially in the countries facing the ageing population.

TRIAL REGISTRATION NUMBER

NCT05982067; ClinicalTrials.gov.

High Sarcopenia Awareness Contrasts a Lack of Clinical Implementation Among Geriatric Rehabilitation Health Care Professionals in the Netherlands: EMPOWER-GR

BACKGROUND AND PURPOSE

Despite being associated with serious adverse outcomes, such as mortality, sarcopenia remains largely undiagnosed in older individuals. This study aimed to assess the awareness, practices, and barriers and enablers to clinical implementation of sarcopenia diagnosis and treatment among geriatric rehabilitation health care professionals in the Netherlands.

METHODS

As part of EMPOWER-GR, a cross-sectional survey among geriatric rehabilitation health care professionals working in the Netherlands was undertaken between September 23, 2020, and January 28, 2021. Professionals were recruited via a geriatric rehabilitation care provider, health care professional associations, professional networks of the research team, and social media. Descriptive statistics were used to assess the study outcomes.

RESULTS AND DISCUSSION

Of the 501 geriatric rehabilitation health care professionals, 12.2% were physicians, 23.0% physical therapist/occupational therapists, 30.3% dietitians, 19.6% nurses, and 11.0% health care assistants. The concept of sarcopenia was known by 83.8% of the participants, 92.5% correctly identified sarcopenia as low muscle mass and strength (and low physical performance), and 73.8% identified sarcopenia as very important in the management of older adults admitted for rehabilitation. Although 26.2% and 18.9% of the participants reported screening and diagnosing sarcopenia, respectively, in their current practice, only 3.0% adequately used the (revised) definition of the European Working Group on Sarcopenia in Older People. When sarcopenia has been diagnosed, 65.0% reported initiating treatment consisting of resistance exercise training (78.7%), food fortification/high-energy or protein diet (85.4%), and oral nutritional supplements (70.4%). Most important barriers to screening and diagnosis were lack of knowledge, access to tools, and equipment and time, while enablers were protocol implementation, access to training, and clear responsibilities.

CONCLUSIONS

Sarcopenia awareness is high among geriatric rehabilitation health care professionals in the Netherlands, but adequate screening and diagnosis is almost nonexistent in current clinical practice, which hampers interventions. Better knowledge, clear responsibilities, and access to tools and protocols, as well as prioritization, are needed for sarcopenia to be diagnosed and treated in geriatric rehabilitation in the Netherlands.

Four-Step Co-Designing of the Reablement Strategies Targeting Sarcopenia (ReStart-S): An Exercise-Based Multicomponent Program for Older Adults Residing in Long-Term Care Settings

Background

The prevalence of sarcopenia is concerningly high in long-term care settings (LTCS); yet, no exercise programs specifically targeting older adults living in residential care are available.

Objective

The goal of the present study was to co-design and validate a program named Reablement Strategies targeting Sarcopenia (ReStart-S) for older long-term care residents.

Design

Cross-sectional study with an exploratory phase.

Settings

LTCS in Udupi, Karnataka, India.

Participants

Sarcopenic older adults diagnosed using Asian Working Group for Sarcopenia 2019 criteria.

Material and Methods

The program was designed using a four-step intervention mapping technique involving systematic progression after completing each step. The steps included 1) identifying the appropriate exercise-based intervention for sarcopenia, 2) determining objectives and expected outcomes, 3) seeking expert views through a Delphi consensus approach, and 4) assessing the feasibility of ReStart-S program among older adults living in LTCS.

Results

A comprehensive literature review appraised existing exercise programs for managing sarcopenia. A workshop held with six older adults and one caretaker, decided on morning exercise sessions, recommended 2-7 days/week. The results of the review and workshop were compiled for the Delphi process that had seven experts from 5 countries, achieving a 71% response rate after four rounds. In the last step, a pilot study on eight LTCS residents, two males and six females with a mean age of 78.3 ± 8.3 years, was conducted and the program was found to be feasible.

Conclusion

The ReStart-S program for managing sarcopenia among older adults residing in LTCS incorporates evidence from the literature and the engagement of older adults, caregivers, and experts, making it a contextually appropriate intervention. Our study also provides researchers and healthcare professionals insight into co-designing an intervention program for vulnerable older adults. Finally, the program evaluation indicates that a full-scale trial testing the efficacy of the ReStart-S program is feasible.

Association between nut consumption and low muscle strength among Korean adults

Nuts are an important component of a healthy diet, but little has been known about their effects on muscle health. Therefore, this study examined the association between nut consumption and low muscle strength among Korean adults. This cross-sectional analysis was conducted using single 24-h recall and handgrip strength data from 3962 younger adults 19-39 years, 6921 middle-aged adults 40-64 years and 3961 older adults ≥65 years participated in the seventh cycle (2016-2018) of the Korea National Health and Nutrition Examination Survey. Low muscle strength was defined as handgrip strength <28 kg for men and <18 kg for women. Sex-specific OR were obtained for younger, middle-aged and older adults using multivariable logistic regression analyses. About one in four Korean adults were consuming nuts (using a culinary definition) with peanut being the most frequently consumed type. After adjustment for age, BMI, total energy intake, household income, alcohol consumption, smoking, resistance exercise, medical history and dietary protein intake, nut consumption was associated with the lower risk of low muscle strength among older adults ≥65 years (men: OR 0·55, 95 % CI (0·38, 0·79); women: OR 0·69, 95 % CI (0·51, 0·93)); however, this association was not observed among younger adults 19-39 years or middle-aged adults 40-64 years. Our results suggest that consuming nuts might be beneficial in lowering the risk of low muscle strength among Korean older adults.

Utility of growth differentiation factor-15 as a predictor of cardiovascular surgery outcomes: Current research and future directions

In a world increasingly confronted by cardiovascular diseases (CVDs) and an aging population, accurate risk assessment prior to cardiac surgery is critical. Although effective, traditional risk calculators such as the Japan SCORE, Society of Thoracic Surgeons score, and EuroSCORE II may not completely capture contemporary risks, particularly due to emerging factors such as frailty and sarcopenia. These calculators often focus on regional and ethnic specificity and rely heavily on evaluations based on age and underlying diseases. Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that has been identified as a potential biomarker for sarcopenia and a tool for future cardiac risk assessment. Preoperative plasma GDF-15 levels have been associated with preoperative, intraoperative, and postoperative factors and short- and long-term mortality rates in patients undergoing cardiac surgery. Increased plasma GDF-15 levels have prognostic significance, having been correlated with the use of cardiopulmonary bypass during surgery, amount of bleeding, postoperative acute kidney injury, and intensive care unit stay duration. Notably, the inclusion of preoperative levels of GDF-15 in risk stratification models enhances their predictive value, especially when compared with those of the N-terminal prohormone of brain natriuretic peptide, which does not lead to reclassification. Thus, this review examines traditional risk assessments for cardiac surgery and the role of the novel biomarker GDF-15. This study acknowledges that the relationship between patient outcomes and elevated GDF-15 levels is not limited to CVDs or cardiac surgery but can be associated with variable diseases, including diabetes and cancer. Moreover, the normal range of GDF-15 is not well defined. Given its promise for improving patient care and outcomes in cardiovascular surgery, future research should explore the potential of GDF-15 as a biomarker for postoperative outcomes and target therapeutic intervention.

The Conceptual Definition of Sarcopenia: Delphi Consensus from the Global Leadership Initiative in Sarcopenia (GLIS)

IMPORTANCE

Sarcopenia, the age-related loss of muscle mass and strength/function, is an important clinical condition. However, no international consensus on the definition exists.

OBJECTIVE

The Global Leadership Initiative in Sarcopenia (GLIS) aimed to address this by establishing the global conceptual definition of sarcopenia.

DESIGN

The GLIS steering committee was formed in 2019-21 with representatives from all relevant scientific societies worldwide. During this time, the steering committee developed a set of statements on the topic and invited members from these societies to participate in a two-phase International Delphi Study. Between 2022 and 2023, participants ranked their agreement with a set of statements using an online survey tool (SurveyMonkey). Statements were categorised based on predefined thresholds: strong agreement (>80%), moderate agreement (70-80%) and low agreement (<70%). Statements with strong agreement were accepted, statements with low agreement were rejected and those with moderate agreement were reintroduced until consensus was reached.

RESULTS

107 participants (mean age: 54 ± 12 years [1 missing age], 64% men) from 29 countries across 7 continents/regions completed the Delphi survey. Twenty statements were found to have a strong agreement. These included; 6 statements on 'general aspects of sarcopenia' (strongest agreement: the prevalence of sarcopenia increases with age (98.3%)), 3 statements on 'components of sarcopenia' (muscle mass (89.4%), muscle strength (93.1%) and muscle-specific strength (80.8%) should all be a part of the conceptual definition of sarcopenia)) and 11 statements on 'outcomes of sarcopenia' (strongest agreement: sarcopenia increases the risk of impaired physical performance (97.9%)). A key finding of the Delphi survey was that muscle mass, muscle strength and muscle-specific strength were all accepted as 'components of sarcopenia', whereas impaired physical performance was accepted as an 'outcome' rather than a 'component' of sarcopenia.

CONCLUSION AND RELEVANCE

The GLIS has created the first global conceptual definition of sarcopenia, which will now serve to develop an operational definition for clinical and research settings.

Relationship between Eating Alone and Handgrip Strength in Korean Older Adults

Sarcopenia is defined as an age-related decline in muscle mass, muscle strength, and physical performance. Eating alone has been linked to various health issues in older adults. This study investigated the relationship between eating alone and handgrip strength (HGS) in older adults using data from 7278 individuals (≥65 years) who participated in the 2014-2019 Korea National Health and Nutrition Examination Survey. HGS was measured using a digital grip strength dynamometer, relative HGS was calculated by dividing HGS by body mass index, and dynapenia was defined as an HGS < 28 kg for men and <18 kg for women. Multivariable logistic regression analysis showed that women who ate two meals alone were more likely to exhibit dynapenia than those who never ate alone (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.03-1.77). If the groups that never ate alone or ate one meal alone were combined as the reference group, the probability of dynapenia was higher in the combined groups that ate two or three meals alone (OR, 1.25; 95% CI, 1.04-1.50). No association was observed between eating alone and dynapenia in men. This suggests that eating alone is a modifiable related factor of dynapenia in older women.

Associations of micronutrient dietary patterns with sarcopenia among US adults: a population-based study

Background

Current epidemiological evidence points to an association between micronutrient (MN) intake and sarcopenia, but studies have focused on single MN, and no combined effects on MNs have been reported. The aim of this study was to investigate the relationship between different MN intake patterns and sarcopenia and skeletal muscle mass.

Methods

We performed a population-based cross-sectional study, with a total of 5,256 U.S. adults aged 20-59 years, and we collected total daily MN intake and appendicular skeletal muscle mass measured by Dual-Energy X-ray Absorptiometry (DXA). Principal component analysis (PCA) was used to obtain nutrient patterns and principal component scores based on the intake of 14 MNs, and logistic regression analysis was used to assess the effects of single MN and MN intake patterns on sarcopenia and muscle mass.

Results

We defined three MN intake patterns by PCA: (1) adherence to VitB-mineral, high intake of vitamin B and minerals; (2) adherence to VitAD-Ca-VB12, high intake of vitamin A, vitamin D, calcium and vitamin B12; and (3) adherence to Antioxidant Vit, high intake of antioxidant vitamins A, C, E, and K. These three nutrient patterns explained 73.26% of the variance of the population. A negative association was observed between most single MN intakes and sarcopenia, and after adjusting for confounders, adherence to the highest tertile of the three nutrient patterns was associated with a lower risk of sarcopenia and relatively higher skeletal muscle mass compared to the lowest adherence. In subgroup analysis, MN intake patterns were significantly correlated with sarcopenia in middle-aged females.

Conclusion

Nutritional patterns based on MN intake were significantly related to sarcopenia, indicating that MNs interact with each other while exerting their individual functions, and that MN dietary patterns may provide promising strategies for preventing the loss of muscle mass, with further prospective studies warranted in the future.

Association between sarcopenia and new-onset chronic kidney disease among middle-aged and elder adults: findings from the China Health and Retirement Longitudinal Study

BACKGROUND

Sarcopenia is a senile syndrome of age-related muscle loss. It is thought to affect the development of chronic kidney disease and has a serious impact on the quality of life of the elder adults. Little is known about the association between sarcopenia and new-onset chronic kidney disease in middle-aged and elder adults. Using nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS), we conducted a longitudinal analysis to investigate the association between sarcopenia status and new-onset chronic kidney disease in middle-aged and elder adults in China.

METHODS

The study population consisted of 3676 participants aged 45 or older selected from 2011 CHARLS database who had no history of chronic kidney disease at the baseline and completed the follow-up in 2015. A multivariate cox regression model was employed to examine the association between sarcopenia and the incidence of new-onset chronic kidney disease.

RESULTS

Followed up for 4 years, a total of 873 (22.5%) new cases of chronic kidney disease occurred. Among them, participants diagnosed with sarcopenia (HR1.45; 95% CI 1.15-1.83) were more likely to develop new-onset chronic kidney disease than those without sarcopenia. Similarly, patients with sarcopenia were more likely to develop new-onset chronic kidney disease than those with possible sarcopenia (HR 1.27; 95%CI 1.00-1.60). Subgroup analysis revealed that elder adults aged between 60 and 75 years old (HR 1.666; 95%CI 1.20-22.28), with hypertension (HR 1.57; 95%CI 1.02-2.40), people with sarcopenia had a significantly higher risk of developing new-onset chronic kidney disease than those without sarcopenia (all P < 0.05).

CONCLUSION

Middle-aged and elder adults diagnosed with sarcopenia have a higher risk of developing new-onset chronic kidney disease.

Association of physical behaviours with sarcopenia in older adults: a systematic review and meta-analysis of observational studies

BACKGROUND

Physical behaviours (ie, physical activity and sedentary behaviour) might have a role in the development of sarcopenia, although the evidence is unclear. We aimed to explore the association of total and intensity-specific levels of physical activity and sedentary behaviour with sarcopenia and its components (ie, muscle mass, muscle strength, and physical performance) in older adults.

METHODS

We conducted a systematic review and meta-analysis and searched MEDLINE (via PubMed), Scopus, and Web of Science from inception to July 26, 2022, for peer-reviewed, observational studies or baseline data from randomised clinical trials conducted in older adults (ie, individual age ≥60 years or mean age ≥65 years) and published in English that reported on the association of physical activity or sedentary behaviour or both with sarcopenia (or its determinants: muscle mass or strength, and physical performance). Physical activity and sedentary behaviour were measured by any method. The main outcome was sarcopenia, which could be diagnosed by any means. Estimates were extracted and pooled using Bayesian meta-analytic models and publication bias was assessed using the Egger's test. This study is registered with PROSPERO, CRD42022315865.

FINDINGS

We identified 15 766 records, of which 124 studies (230 174 older adults; 121 301 [52·7%] were female and 108 873 [47·3%] were male) were included in the systematic review. 86 studies were subsequently included in the meta-analysis. Higher levels of total physical activity were inversely associated with sarcopenia both cross-sectionally (21 studies, n=59 572; odds ratio 0·49, 95% credible interval 0·37-0·62) and longitudinally (four studies, n=7545; 0·51, 0·27-0·94). A protective association was also identified for moderate-to-vigorous physical activity in cross-sectional research (five studies, n=6787; 0·85, 0·71-0·99), whereas no association was identified for the remaining physical behaviours (ie, steps, light physical activity, or sedentary behaviour).

INTERPRETATION

Total and moderate-to-vigorous physical activity are inversely associated with sarcopenia. These findings might support the importance of moderate-to-vigorous, rather than light, intensity physical activity-based interventions to prevent sarcopenia.

FUNDING

None.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Effects of resistance training and nutritional support on osteosarcopenia in older, community-dwelling postmenopausal Korean females (ERTO-K study): a study protocol

BACKGROUND

Osteosarcopenia is geriatric syndrome defined as the concomitant occurrence of osteopenia/osteoporosis, and sarcopenia. Osteosarcopenia is a relatively new concept in geriatric medicine; however, it may increase the risk of fragility fractures, several morbidities and mortalities, and socioeconomic costs. Although resistance exercises and nutritional support-including protein, calcium, and vitamin D-are potential non-pharmacological management procedures, evidence is still lacking. The objective of this study was therefore to evaluate the effect of combined resistance exercise and nutritional support on the quality and quantity of bone and muscle in postmenopausal females with osteosarcopenia.

METHODS

This research proposal presents the protocol for a prospective, single-center, single-blinded, two-armed randomized controlled trial. Thirty-four participants with osteosarcopenia will be recruited and randomly divided into intervention and control groups; both groups will receive nutritional supplements (protein, 40 g; vitamin D, 1600 IU; calcium, 600 mg) daily. The intervention group will undergo 24 weeks of resistance exercise of increasing intensity, achieved through a three-phase step-up process. The primary outcomes will be the changes in skeletal muscle index and bone marrow density of the lumbar spine and femoral neck between the baseline and end of intervention (24 weeks). The secondary outcomes will be the body composition, whole body phase angle, physical function assessment, quality of life, psychological assessment, and bone turnover markers of participants, surveyed at multiple time points.

DISCUSSION

This randomized controlled trial may reveal the effect of resistance exercise and nutritional support on older postmenopausal women with osteosarcopenia. The results will provide evidence for developing proper non-pharmacological management guidelines for postmenopausal women.

TRIAL REGISTRATION

Clinical Research Information Service of Republic of Korea, KCT0008291, Registered on 16 March 2023, https://cris.nih.go.kr/cris/search/detailSearch.do/25262 .

Sarcopenia of Ageing: Does a Healthier Lifestyle Matter in Reversing the Trajectory? A Brief Narrative Review and a Call for Action in Saudi Arabia

The concept of health span is an emerging topic in recent years, with a truly palpable relevance to public health. With ageing comes a loss of skeletal muscle mass, strength, and performance, which is termed as sarcopenia. Sarcopenia is a major public health concern and poses a challenge to health-care systems. Modifiable lifestyle factors may be linked to the course of sarcopenia progression. Many countries developed diagnostic tools to accurately detect sarcopenia for its prevention, delay, or treatment. However, to date, there is no sufficient information regarding the status of sarcopenia in Saudi Arabia. The review aims to discuss sarcopenia and relevant updates in research and literature, the association with modifiable lifestyle factors, the implications of sarcopenia in a rapidly developing country such as Saudi Arabia, and the current state and need for research in Saudi Arabia in this domain along with future directions in combating this disease.

A Combination Study of Pre- and Clinical Trial: Seaweed Consumption Reduces Aging-Associated Muscle Loss!

Seaweed consumption in Asian food cultures may benefit longevity and age-related conditions like sarcopenia with aging. However, sarcopenia lacks a definitive treatment, and pharmaceutical options have limitations in efficacy and safety. Recent studies on aging female mice found that Ishige okamurae (IO), a brown algae, and its active compound diphloroethohydroxycarmalol improved sarcopenia. Further research is needed to understand the effects of seaweed consumption on sarcopenia in humans. This clinical trial divided participants into a test group (receiving 500 mg/kg IO supplementation, mean±SD; age 62.73±7.18 years, n=40) and a control group (age 63.10±7.06 years, n=40). Hazard analysis assessed vital signs and muscle strength improvement during the trial. Additionally, 12-month-old mice were oral-fed IO at different doses (50, 100, 200 mg/kg) for 6-weeks. Aging and muscle-wasting related markers were evaluated, including grip strength, body weight and compositions, serum-parameters, and molecular-changes. The clinical trial found no significant changes in toxicity-parameters between the groups (p<0.05) after 12-weeks of IO supplementation. The IO group exhibited a remarkable increase in lower-limb quadriceps muscle-strength compared to the control (p=0.002). Furthermore, IO treatment improved age-related decline in quadriceps strength in the subgroup; under 61-years-old (p=0.004), without significant differences in foot-dominancy between groups (p=0.171). In 12-month-old male mice, IO administration improved age-related deficiencies in grip strength (p>0.0001) and testosterone (p=0.0001). Muscular regeneration parameters, such as lean-mass (p>0.0001), inhibition of proteolysis (measured by changes in myogenin and atrogin-1 protein expressions), cross-sectional myofiber area (p>0.0001), number of satellite cells (p=0.0001), and increased mitochondrial oxidative phosphorylation complexes in muscle tissue indicative of mitochondrial biogenesis, were also improved by IO administration. This trial is the first to explore the positive association between consuming brown-algae IO and age-related decreases in muscle strength. IO treatment helps maintain muscle mass and delays muscle wasting during aging, suggesting it as a potent nutritional strategy to protect against aging-associated sarcopenia.

[GDF5: a therapeutic candidate for combating sarcopenia]

Sarcopenia is a complex age-related muscular disease affecting 10 to 16 % of people over 65 years old. It is characterized by excessive loss of muscle mass and strength. Despite a plethora of studies aimed at understanding the physiological mechanisms underlying this pathology, the pathophysiology of sarcopenia remains poorly understood. To date, there is no pharmacological treatment for this disease. In this context, our team develop therapeutic approaches based on the GDF5 protein to counteract the loss of muscle mass and function in various pathological conditions, including sarcopenia. After deciphering one of the molecular mechanisms governing GDF5 expression, we have demonstrated the therapeutic potential of this protein in the preservation of muscle mass and strength in aged mice.

Evaluation of Probable Sarcopenia's Prevalence in Hospitalized Geriatric Patients Using Ishii's Score

BACKGROUND

Sarcopenia is defined as a progressive loss of skeletal muscle mass and strength related to age and comorbidities. Worldwide sarcopenia's prevalence varies between 10-40%, being associated with functional impairment, lower quality of life, and higher mortality. Sarcopenia can be estimated based on age, calf circumference, and handgrip strength (Ishii's formula). Early diagnosis is essential because treatment with nutritional support and rehabilitation programs can prevent complications. The aim of the study was to assess the prevalence of probable sarcopenia in hospitalized patients using Ishii's score and possible associated risk factors.

METHODS

We developed an observational prospective study in a medicine inpatient ward of a Central Hospital. We applied Ishii's formula to the patients admitted to the medical ward in December 2021 and January 2022. Patients should be aged 60 or above and able to collaborate with the tests. One year later, we analyzed re-hospitalization and mortality rates. Patients with edema of the lower limbs, who were not able to follow instructions, and who were admitted exclusively for symptomatic treatment were excluded.

RESULTS

Our final sample was 49 patients (55% males, mean age 78 ± 8.88 years). Only one patient had a previous diagnosis of sarcopenia. Estimated sarcopenia´s prevalence was 73.5% N=36), higher in men and people with three or more comorbidities. In the sarcopenic group, 77% had some degree of functional dependency and positive markers for malnutrition. After one year of follow-up, we found a higher mortality rate in the sarcopenic group (44.4% against 7.6%) and a higher number of re-hospitalizations (1.03 hospitalizations per patient, against 0.31).

CONCLUSIONS

Our data showed that the prevalence of probable sarcopenia is high, but this pathology is still underdiagnosed. Traditional diagnosis is complex in some hospital settings and a simple tool such as Ishii's score can help to improve diagnostic rates. We suggest screening all patients at admission to provide early rehabilitation and nutritional support.

Regional recruitment and differential behavior of motor units during postural control in older adults

Aging is associated with neuromuscular system changes that may have implications for the recruitment and firing behaviors of motor units (MUs). In previous studies, we observed that young adults recruit subpopulations of triceps surae MUs during tasks that involved leaning in five directions: common units that were active during different leaning directions and unique units that were active in only one leaning direction. Furthermore, the MU subpopulation firing behaviors [average firing rate (AFR), coefficient of variation (CoVISI), and intermittent firing] modulated with leaning direction. The purpose of this study was to examine whether older adults exhibited this regional recruitment of MUs and firing behaviors. Seventeen older adults (aged 74.8 ± 5.3 yr) stood on a force platform and maintained their center of pressure leaning in five directions. High-density surface electromyography recordings from the triceps surae were decomposed into single MU action potentials. A MU tracking analysis identified groups of MUs as being common or unique across the leaning directions. Although leaning in different directions did not affect the AFR and CoVISI of common units (P > 0.05), the unique units responded to the leaning directions by increasing AFR and CoVISI, albeit modestly (F = 18.51, P < 0.001). The unique units increased their intermittency with forward leaning (F = 9.22, P = 0.003). The mediolateral barycenter positions of MU activity in both subpopulations were found in similar locations for all leaning directions (P > 0.05). These neuromuscular changes may contribute to the reduced balance performance seen in older adults.NEW & NOTEWORTHY In this study, we observed differences in motor unit recruitment and firing behaviors of distinct subpopulations of motor units in the older adult triceps surae muscle from those observed in the young adult. Our results suggest that the older adult central nervous system may partially lose the ability to regionally recruit and differentially control motor units. This finding may be an underlying cause of balance difficulties in older adults during directionally challenging leaning tasks.

Performance Evaluation of Machine Learning Algorithms for Sarcopenia Diagnosis in Older Adults

BACKGROUND

Sarcopenia is a progressive and generalized skeletal muscle disorder. Early diagnosis is necessary to reduce the adverse effects and consequences of sarcopenia, which can help prevent and manage it in a timely manner. The aim of this study was to identify the important risk factors for sarcopenia diagnosis and compare the performance of machine learning (ML) algorithms in the early detection of potential sarcopenia.

METHODS

A cross-sectional design was employed for this study, involving 160 participants aged 65 years and over who resided in a community. ML algorithms were applied by selecting 11 features-sex, age, BMI, presence of hypertension, presence of diabetes mellitus, SARC-F score, MNA score, calf circumference (CC), gait speed, handgrip strength (HS), and mid-upper arm circumference (MUAC)-from a pool of 107 clinical variables. The results of the three best-performing algorithms were presented.

RESULTS

The highest accuracy values were achieved by the ALL (male + female) model using LightGBM (0.931), random forest (RF; 0.927), and XGBoost (0.922) algorithms. In the female model, the support vector machine (SVM; 0.939), RF (0.923), and k-nearest neighbors (KNN; 0.917) algorithms performed the best. Regarding variable importance in the ALL model, the last HS, sex, BMI, and MUAC variables had the highest values. In the female model, these variables were HS, age, MUAC, and BMI, respectively.

CONCLUSIONS

Machine learning algorithms have the ability to extract valuable insights from data structures, enabling accurate predictions for the early detection of sarcopenia. These predictions can assist clinicians in the context of predictive, preventive, and personalized medicine (PPPM).

Effects of resistance training on sarcopenia in patients with intestinal failure: A randomized controlled trial

BACKGROUND

The potential effects of resistance training on sarcopenia in patients with intestinal failure (IF) are not fully elucidated. This study aimed to explore the efficacy of a resistance training program on appendicular skeletal muscle index (ASMI), physical performance, body composition, biochemical parameters, and health-related quality of life (HRQOL) in patients with IF exhibiting sarcopenia.

METHODS

A single-center randomized controlled trial was conducted in a Chinese tertiary teaching hospital. Patients with IF exhibiting sarcopenia were randomly assigned to the exercise group or control group. Participants in the exercise group incorporated four sets of resistance training involving the limbs and abdominal and lower back muscles, six times weekly for 4 weeks. The control group received no specific intervention. The primary outcome was the between-group difference in ASMI 4 weeks after intervention. Secondary outcomes included handgrip strength, 6-m gait speed, body composition, biochemical parameters, and HRQOL.

RESULTS

A total of 60 participants (control group 30, age 51.2 ± 12.9 years, women 43.3%; exercise group 30, age 53.9 ± 14.5 years, women 56.7%) completed the 4-week intervention trial. For the primary outcome, significant intervention effects were found in ASMI between the exercise group and the control group (mean difference 0.72, 95% CI, 0.56-0.89, P < 0.001). There were notable differences in handgrip strength (mean difference 2.7, 95% CI, 1.7-3.6, P < 0.001), 6-m gait speed (mean difference 0.08, 95% CI, 0.01-0.35, P = 0.034), body composition (including total cell mass, bone mineral content, skeletal muscle mass, lean mass, visceral fat area, total body water, intracellular water, extracellular water, and segmental water-legs), and biochemical parameters (including IGF-1, prealbumin, and hemoglobin) between the two groups (P < 0.05). No significant intervention benefits were observed for other secondary outcomes, including biochemical parameters (including albumin, total bilirubin, etc.) and HRQOL (P > 0.05).

CONCLUSIONS

In this randomized clinical trial, we observed that 4 weeks of resistance training was associated with improved ASMI, physical performance, biochemical parameters (including IGF-1, prealbumin, and hemoglobin), and body composition in IF patients with sarcopenia. Resistance training can be recommended as a simple and effective method to improve sarcopenia in patients with IF.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn, identifier: ChiCTR2100051727.

Neurosurgical perioperative management of frail elderly patients

With the rapid increase in global aging, the prevalence of frailty is increasing and frailty has emerged as an emerging public health burden. Frail elderly patients suffer from reduced homeostatic reserve capacity, which is associated with a disproportionate decline in physical status after exposure to stress and an increased risk of adverse events. Frailty is closely associated with changes in the volume of the white and gray matter of the brain. Sarcopenia has been suggested to be an important component of frailty, and reductions in muscle strength and muscle mass lead to reductions in physical function and independence, which are critical factors contributing to poor prognosis. Approximately 10-32% of patients undergoing neurological surgery are frail, and the risk of frailty increases with age, which is significantly associated with the occurrence of adverse postoperative events (major complications, total duration of hospitalization, and need for discharge to a nursing facility). The postoperative mortality rate in severely frail patients is 9-11 times higher than that in non-frail individuals. Therefore, due attention must be paid to neurosurgical frailty and muscle assessment in elderly patients. Specialized interventions in the perioperative period of neurosurgery in frail elderly patients may improve their postoperative prognosis.

Emergence and Progression of Behavioral Motor Deficits and Skeletal Muscle Atrophy across the Adult Lifespan of the Rat

The facultative loss of muscle mass and function during aging (sarcopenia) poses a serious threat to our independence and health. When activities of daily living are impaired (clinical phase), it appears that the processes leading to sarcopenia have been ongoing in humans for decades (preclinical phase). Here, we examined the natural history of sarcopenia in male outbred rats to compare the occurrence of motor behavioral deficits with the degree of muscle wasting and to explore the muscle-associated processes of the preclinical and clinical phases, respectively. Selected metrics were validated in female rats. We used the soleus muscle because of its long duty cycles and its importance in postural control. Results show that gait and coordination remain intact through middle age (40-60% of median lifespan) when muscle mass is largely preserved relative to body weight. However, the muscle shows numerous signs of remodeling with a shift in myofiber-type composition toward type I. As fiber-type prevalence shifted, fiber-type clustering also increased. The number of hybrid fibers, myofibers with central nuclei, and fibers expressing embryonic myosin increased from being barely detectable to a significant number (5-10%) at late middle age. In parallel, TGFβ1, Smad3, FBXO32, and MuRF1 mRNAs increased. In early (25-month-old) and advanced (30-month-old) aging, gait and coordination deteriorate with the progressive loss of muscle mass. In late middle age and early aging due to type II atrophy (>50%) followed by type I atrophy (>50%), the number of myofibers did not correlate with this process. In advanced age, atrophy is accompanied by a decrease in SCs and βCatenin mRNA, whereas several previously upregulated transcripts were downregulated. The re-expression of embryonic myosin in myofibers and the upregulation of mRNAs encoding the γ-subunit of the nicotinic acetylcholine receptor, the neuronal cell adhesion molecule, and myogenin that begins in late middle age suggest that one mechanism driving sarcopenia is the disruption of neuromuscular connectivity. We conclude that sarcopenia in rats, as in humans, has a long preclinical phase in which muscle undergoes extensive remodeling to maintain muscle mass and function. At later time points, these adaptive mechanisms fail, and sarcopenia becomes clinically manifest.

Sarcopenia in Type 2 Diabetes Mellitus: Study of the Modifiable Risk Factors Involved

(1) Background: Sarcopenia has gained much interest in recent years due to an increase in morbidity. Sarcopenia is associated with type 2 diabetes mellitus (T2DM) and vice versa. There is a paucity of information regarding the prevalence and predictors of sarcopenia among T2DM individuals. The aim of the present study was to determine the prevalence and predictors of sarcopenia among T2DM individuals. (2) Methods: This study included 159 diabetics (cases) and 79 non-diabetics (controls) aged >50 years. The subjects were assessed for demographic and anthropometric parameters. Sarcopenia (according to the Asian Working Group for Sarcopenia 2019 criteria) was assessed using Jammer's hydraulic dynamometer for handgrip strength, dual-energy X-ray absorptiometry for muscle mass, and 6m gait speed. The biochemical investigations included glycated hemoglobin; fasting and prandial glucose; fasting insulin; lipid, renal, liver, and thyroid profiles; serum calcium; phosphorous; vitamin D; and parathyroid hormone (PTH). Appropriate statistical methods were used to determine the significance of each parameter, and a multivariate regression analysis was applied to determine the predictors. (3) Results: The prevalence of sarcopenia was significantly higher among the cases than the controls (22.5% vs. 8.86%, p-0.012). Body mass index (BMI) (OR-0.019, CI-0.001-0.248), physical activity (OR-0.45, CI-0.004-0.475), serum calcium levels (OR-0.155, CI-0.035-0.687), hypertension (OR-8.739, CI-1.913-39.922), and neuropathy (OR-5.57, CI-1.258-24.661) were significantly associated with sarcopenia following multivariate regression analysis. (4) Conclusions: T2DM individuals are prone to sarcopenia, especially those with a low BMI, low physical activity, hypertension, neuropathy, and low serum calcium levels. Hence, by modifying these risk factors among the elderly T2DM, sarcopenia can be prevented.

Neuromuscular junction transmission failure in aging and sarcopenia: The nexus of the neurological and muscular systems

Sarcopenia, or age-related decline in muscle form and function, exerts high personal, societal, and economic burdens when untreated. Integrity and function of the neuromuscular junction (NMJ), as the nexus between the nervous and muscular systems, is critical for input and dependable neural control of muscle force generation. As such, the NMJ has long been a site of keen interest in the context of skeletal muscle function deficits during aging and in the context of sarcopenia. Historically, changes of NMJ morphology during aging have been investigated extensively but primarily in aged rodent models. Aged rodents have consistently shown features of NMJ endplate fragmentation and denervation. Yet, the presence of NMJ changes in older humans remains controversial, and conflicting findings have been reported. This review article describes the physiological processes involved in NMJ transmission, discusses the evidence that supports NMJ transmission failure as a possible contributor to sarcopenia, and speculates on the potential of targeting these defects for therapeutic development. The technical approaches that are available for assessment of NMJ transmission, whether each approach has been applied in the context of aging and sarcopenia, and the associated findings are summarized. Like morphological studies, age-related NMJ transmission deficits have primarily been studied in rodents. In preclinical studies, isolated synaptic electrophysiology recordings of endplate currents or potentials have been mostly used, and paradoxically, have shown enhancement, rather than failure, with aging. Yet, in vivo assessment of single muscle fiber action potential generation using single fiber electromyography and nerve-stimulated muscle force measurements show evidence of NMJ failure in aged mice and rats. Together these findings suggest that endplate response enhancement may be a compensatory response to post-synaptic mechanisms of NMJ transmission failure in aged rodents. Possible, but underexplored, mechanisms of this failure are discussed including the simplification of post-synaptic folding and altered voltage-gated sodium channel clustering or function. In humans, there is limited clinical data that has selectively investigated single synaptic function in the context of aging. If sarcopenic older adults turn out to exhibit notable impairments in NMJ transmission (this has yet to be examined but based on available evidence appears to be plausible) then these NMJ transmission defects present a well-defined biological mechanism and offer a well-defined pathway for clinical implementation. Investigation of small molecules that are currently available clinically or being testing clinically in other disorders may provide a rapid route for development of interventions for older adults impacted by sarcopenia.

Sex differences in skeletal muscle-aging trajectory: same processes, but with a different ranking

Sex differences in muscle aging are poorly understood, but could be crucial for the optimization of sarcopenia-related interventions. To gain insight into potential sex differences in muscle aging, we recruited young (23 ± 2 years, 13 males and 13 females) and old (80 ± 3.5 years, 28 males and 26 females) participants. Males and females in both groups were highly matched, and vastus lateralis muscle parameters of old versus young participants were compared for each sex separately, focusing on gene expression. The overall gene expression profiles separated the sexes, but similar gene expression patterns separated old from young participants in males and females. Genes were indeed regulated in the same direction in both sexes during aging; however, the magnitude of differential expression was sex specific. In males, oxidative phosphorylation was the top-ranked differentially expressed process, and in females, this was cell growth mediated by AKT signaling. Findings from RNA-seq data were studied in greater detail using alternative approaches. In addition, we confirmed our data using publicly available data from three independent human studies. In conclusion, top-ranked pathways differ between males and females, but were present and altered in the same direction in both sexes. We conclude that the same processes are associated with skeletal muscle aging in males and females, but the differential expression of those processes in old vs. young participants is sex specific.

Identification of a novel immune-related transcriptional regulatory network in sarcopenia

BACKGROUND

Sarcopenia is highly prevalent in elderly individuals and has a significant adverse effect on their physical health and quality of life, but the mechanisms remain unclear. Studies have indicated that transcription factors (TFs) and the immune microenvironment play a vital role in skeletal muscle atrophy.

METHODS

RNA-seq data of 40 muscle samples were downloaded from the GEO database. Then, differentially expressed genes (DEGs), TFs(DETFs), pathways(DEPs), and the expression of immune gene sets were identified with limma, edgeR, GO, KEGG, ORA, GSVA, and ssGSEA. Furthermore, the results above were integrated into coexpression analysis by Pearson correlation analysis (PCA). Significant coexpression patterns were used to construct the immune-related transcriptional regulatory network by Cytoscape and potential medicine targeting the network was screened by Connectivity Map. Finally, the regulatory mechanisms and RNA expression of DEGs and DETFs were identified by multiple online databases and RT‒qPCR.

RESULTS

We screened 808 DEGs (log2 fold change (FC) > 1 or <  - 1, p < 0.05), 4 DETFs (log2FC > 0.7 or <  - 0.7, p < 0.05), 304 DEPs (enrichment scores (ES) > 1 or <  - 1, p < 0.05), and 1208 differentially expressed immune genes sets (DEIGSs) (p < 0.01). Based on the results of PCA (correlation coefficient (CC) > 0.4 or <  - 0.4, p < 0.01), we then structured an immune-related network with 4 DETFs, 9 final DEGs, 11 final DEPs, and 6 final DEIGSs. Combining the results of online databases and in vitro experiments, we found that PAX5-SERPINA5-PI3K/Akt (CC ≤ 0.444, p ≤ 0.004) was a potential transcriptional regulation axis, and B cells (R = 0.437, p = 0.005) may play a vital role in this signal transduction. Finally, the compound of trichostatin A (enrichment = -0.365, specificity = 0.4257, p < 0.0001) might be a potential medicine for sarcopenia based on the PubChem database and the result of the literature review.

CONCLUSIONS

We first identified immune-related transcriptional regulatory network with high-throughput RNA-seq data in sarcopenia. We hypothesized that PAX5-SERPIAN5-PI3K/Akt axis is a potential mechanism in sarcopenia and that B cells may play a vital role in this signal transduction. In addition, trichostatin A might be a potential medicine for sarcopenia.

Risk of Sarcopenia and Associated Factors in Older Adults with Type 2 Diabetes: An Exploratory Cross-Sectional Study

BACKGROUND

Evidence on the risk of sarcopenia and associated factors in older adults with type 2 diabetes (T2D) is lacking. We evaluate (1) the proportion of patients at risk of sarcopenia in older adults with T2D; and (2) the factors associated with the risk of sarcopenia.

METHODS

We conducted a cross-sectional study on T2D patients over 65 years referred to our outpatient clinic and who carried out the yearly complication assessment visit. Eligible patients were administered questionnaires during phone interviews for the risk evaluation of sarcopenia (SARC-F), the risk evaluation of malnutrition (Mini Nutritional Assessment Short Form (MNA^®-SF)), the adherence to the Mediterranean diet (MEDI-quest), and the evaluation of physical activity (the International Physical Activity Questionnaire short form).

RESULTS

A total of 138 patients were included in the study, and 12 patients (8.7% (95% CI 4.6-14.7)) were at risk of sarcopenia. The mean SARC-F score was significantly higher in women compared with men (2.1 ± 1.8 vs. 0.9 ± 1.4, respectively; p < 0.001). The majority of patients identified at risk of sarcopenia compared with those not at risk were women (75% vs. 30%, respectively; p = 0.003), had a higher proportion of neuropathy (50% vs. 19%, respectively; p = 0.027), a lower mean MNA^®-SF score (11.6 ± 1.5 vs. 13.0 ± 1.4, respectively; p = 0.001), a lower mean MEDI-quest score (5.2 ± 1.5 vs. 5.9 ± 1, respectively; p = 0.037), and were more inactive (92% vs. 61%, respectively; p = 0.032).

CONCLUSIONS

In a sample of older adults with T2D, the risk of sarcopenia was identified in 8.7% (95% CI: 4.6-14.7) of the sample, and the main factors associated were female gender, neuropathy, a lower MNA^®-SF score, low adherence to the Mediterranean diet, and low physical activity.

Physical activity and osteosarcopenia in Korean adults aged 65 years and older: a national cross-sectional study using the KNHANES data

BACKGROUND

Osteosarcopenia is a syndrome characterized by the co-existence of osteoporosis and sarcopenia. This study aimed to examine the relationship between various types of physical activity and osteosarcopenia in community-dwelling Korean adults aged 65 years or older.

METHODS

This cross-sectional study used raw data from the fourth and fifth editions of the Korean National Health and Nutritional Survey Examination, conducted from 2008 to 2011. The researchers exclusively recruited participants aged 65 years or older for the study. These participants were categorized into four distinct groups based on their clinical factors, namely individuals without osteoporosis or sarcopenia, those with osteoporosis alone, those with sarcopenia alone, and individuals with osteosarcopenia. The International Physical Activity Short-Form was used to calculate the weekly time spent walking, moderate-intensity aerobic physical activity, and vigorous aerobic physical activity. Number of days in performing strengthening or stretching exercises were also surveyed. We used logistic regression analyses to examine the association between various physical activities and occurrence of osteosarcopenia.

RESULTS

A total of 1,342 participants (639 men and 703 women) were included in the analysis. No significant difference was observed in the amount and level of aerobic physical activity between the groups. The odds ratios below were based on participants without osteoporosis or sarcopenia as the reference category. The un-adjusted odds ratio of participants who performed stretching (male, 0.179, 95% CI 0.078-0.412; female 0.430, 95% CI 0.217-0.853) and strengthening exercises (male, 0.143, 95% CI 0.051-0.402; female, 0.044, 95% CI 0.006-0.342) at least twice per week was significantly lower in participants with osteosarcopenia compared to those without. In the adjusted analysis (adjusted by age, body mass index, house income, educational level, smoking habits, drinking status, and protein intake), only female patients in the osteosarcopenia group had a significantly lower adjusted odds ratio for performing strengthening exercise compared to female participants without osteoporosis or sarcopenia (0.062, 95% CI 0.007-0.538).

CONCLUSIONS

After adjusting for confounding factors and protein intake, women aged 65 years and older who suffered osteosarcopenia had considerably lower odds ratio of performing strengthening exercises.

Radiologic Features of T10 Paravertebral Muscle Sarcopenia: Prognostic Factors in COVID-19

Background

Sarcopenia, defined as a small cross-sectional area (CSA) in computed tomography (CT) measurements of skeletal muscles, serves as a disease severity marker in various clinical scenarios, including pulmonary conditions and critical illness. Another parameter of sarcopenia, the level of myosteatosis, reflected by the tissue's radiodensity, in the thoracic skeletal muscles group, has been linked to disease progression in coronavirus disease 2019 (COVID-19) patients. We hypothesize that CT-derived measurements of the skeletal muscle density (SMD) and the CSA of thoracic skeletal muscles can predict outcomes in COVID-19 pneumonia.

Methods

We retrospectively reviewed the CT scans of 84 patients with COVID-19 pneumonia admitted to two of Greece's largest academic teaching hospitals between April 2020 and February 2021. CSA and SMD at the level of the T10 vertebra were measured using computational imaging methods. The patient population was stratified according to survival status and CT severity score (CT-SS). Correlations were drawn between the radiologic features of sarcopenia, CT severity subgroups, serum inflammatory markers, and adverse events, e.g., death and intubation.

Results

Thoracic muscles' CSA measurements correlate with CT-SS and prominent inflammatory markers, such as white blood cell (WBC), C-reactive protein (CRP), fibrinogen, and D-dimers. Moreover, according to linear regression analysis, CSA seems to predict CT-SS variation significantly (β = -0.266, P = 0.018). CSA proved to differ significantly across survivors (P = 0.027) but not between CT severity categories and intubation subgroups. The AUC (area under the curve) of the receiver operating characteristic (ROC) curve for the predictive value of thoracic muscles' CSA in mortality is 0.774 (95% confidence interval (CI): 0.66 - 0.83, P < 0.000). The optimal cut-off value (Youden index = 0.57) for mortality prognosis, with a sensitivity of 66.7% and a specificity of 88.9%, is 15.55. Thoracic muscles' SMD analyses did not reveal any significant correlations.

Conclusions

Easy to obtain and accurately calculated, radiologic features can provide a reliable alternative to laboratory methods for predicting survival in COVID-19. Thoracic muscles' CSA measurement in the level of the T10 vertebra, an acclaimed prognostic imaging assessment that relates directly to CT-SS and inflammatory markers in COVID-19 pneumonia, is a fairly specific tool for survival prognosis.

Comparison of traditional vs. lighter load strength training on fat-free mass, strength, power and affective responses in middle and older-aged adults: A pilot randomized trial

OBJECTIVES

Strength training is widely recommended to improve strength, muscle mass and power. However, the feasibility and potential efficacy of strength training using lighter loads near failure on these outcomes in middle and older-aged adults remains unclear.

METHODS

23 community-living adults were randomized into two groups: Traditional strength training (ST) (8-12 repetitions) or a lighter load, higher repetitions (LLHR) (20-24 repetitions) group. Participants performed a full-body workout (twice a week) with 8 exercises at a perceived exertion of 7-8 (0-10 scale) for 10 weeks. Post-testing was performed by an assessor blinded to group assignments. An analysis of covariance (ANCOVA) was used to examine between group differences using baseline values as a covariate.

RESULTS

The study involved individuals with a mean age of 59 years, of which 61 % were women. The LLHR group demonstrated a high attendance rate of 92 % (9.5 %) and reported leg press exercise RPE of 7.1 (0.53), along with a session feeling scale of 2.0 (1.7). There was a trivial difference in fat free mass (FFM) favoring LLHR vs ST [0.27 kg 95 % CI (-0.87, 1.42)]. The ST group exhibited superior increases in leg press 1 repetition maximum (1RM) strength [-14 kg (-23, -5)], while the LLHR group showed greater strength endurance increases (65 % 1RM) [8 repetitions (2, 14)]. Leg press power [41 W (-42, 124)] and exercise efficacy [-3.8 (-21.2, 13.5)] demonstrated trivial between-group differences.

CONCLUSION

A pragmatic, full-body strength training program with lighter loads taken close to failure appears to be a viable option for promoting muscular adaptations in middle- and older-aged adults. These results are exploratory and require a larger trial for confirmation.

Prevalence and risk factors of osteosarcopenia: a systematic review and meta-analysis

BACKGROUND

Osteosarcopenia is a syndrome with a concomitant presence of both sarcopenia and osteopenia/osteoporosis. It increases the risk of frailty, falls, fractures, hospitalization, and death. Not only does it burden the lives of older adults, but it also increases the economic burden on health systems around the world. This study aimed to review the prevalence and risk factors of osteosarcopenia to generate important references for clinical work in this area.

METHODS

Pubmed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang, CBM, and VIP databases were searched from inception until April 24th, 2022. The quality of studies included in the review was evaluated using the NOS and AHRQ Scale. Pooled effects of the prevalence and associated factors were calculated using random or fixed effects models. Egger's test, Begg's test, and funnel plots were used to test the publication bias. Sensitivity analysis and subgroup analysis were conducted to identify the sources of heterogeneity. Statistical analysis was performed using Stata 14.0 and Review Manager 5.4.

RESULTS

A total of 31 studies involving 15,062 patients were included in this meta-analysis. The prevalence of osteosarcopenia ranged from 1.5 to 65.7%, with an overall prevalence of 21% (95% CI: 0.16-0.26). The risk factors for osteosarcopenia were female (OR 5.10, 95% CI: 2.37-10.98), older age (OR 1.12, 95% CI: 1.03-1.21), and fracture (OR 2.92, 95% CI: 1.62-5.25).

CONCLUSION

The prevalence of osteosarcopenia was high. Females, advanced age, and history of fracture were independently associated with osteosarcopenia. It is necessary to adopt integrated multidisciplinary management.

Effects of Exercise Training on Muscle Quality in Older Individuals: A Systematic Scoping Review with Meta-Analyses

BACKGROUND

The quantity and quality of skeletal muscle are important determinants of daily function and metabolic health. Various forms of physical exercise can improve muscle function, but this effect can be inconsistent and has not been systematically examined across the health-neurological disease continuum. The purpose of this systematic scoping review with meta-analyses was to determine the effects and potential moderators of exercise training on morphological and neuromuscular muscle quality (MMQ, NMQ) in healthy older individuals. In addition and in the form of a scoping review, we examined the effects of exercise training on NMQ and MMQ in individuals with neurological conditions.

METHODS

A systematic literature search was performed in the electronic databases Medline, Embase, and Web of Science. Randomized controlled trials were included that examined the effects of exercise training on muscle quality (MQ) in older individuals with and without neurological conditions. Risk of bias and study quality were assessed (Cochrane Risk of Bias Tool 2.0). We performed random-effects models using robust variance estimation and tested moderators using the approximate Hotelling-Zhang test.

RESULTS

Thirty studies (n = 1494, 34% females) in healthy older individuals and no studies in individuals with neurological conditions were eligible for inclusion. Exercise training had small effects on MMQ (g = 0.21, 95% confidence interval [CI]: 0.03-0.40, p = 0.029). Heterogeneity was low (median I² = 16%). Training and demographic variables did not moderate the effects of exercise on MMQ. There was no association between changes in MMQ and changes in functional outcomes. Exercise training improved NMQ (g = 0.68, 95% CI 0.35-1.01, p < 0.000) across all studies, in particular in higher-functioning older individuals (g = 0.72, 95% CI 0.38-1.06, p < 0.001), in lower extremity muscles (g = 0.74, 95% CI 0.35-1.13, p = 0.001), and after resistance training (g = 0.91; 95% CI 0.42-1.41, p = 0.001). Heterogeneity was very high (median I² = 79%). Of the training and demographic variables, only resistance training moderated the exercise-effects on NMQ. High- versus low-intensity exercise moderated the exercise-effects on NMQ, but these effects were considered unreliable due to a low number of studies at high intensity. There was no association between changes in NMQ and changes in functional outcomes.

CONCLUSION

Exercise training has small effects on MMQ and medium-large effects on NMQ in healthy older individuals. There was no association between improvements in MQ and increases in muscle strength, mobility, and balance. Information on dose-response relations following training is currently lacking. There is a critical gap in muscle quality data for older individuals with lower function and neurological conditions after exercise training. Health practitioners should use resistance training to improve muscle function in older individuals. Well-designed studies are needed to examine the relevance of exercise training-induced changes in MQ in daily function in older individuals, especially to those with lower function and neurological conditions.

A Comprehensive Review of Pathological Mechanisms and Natural Dietary Ingredients for the Management and Prevention of Sarcopenia

Sarcopenia is characterized by an age-related loss of skeletal muscle mass and function and has been recognized as a clinical disease by the World Health Organization since 2016. Substantial evidence has suggested that dietary modification can be a feasible tool to combat sarcopenia. Among various natural dietary ingredients, the present study focused on botanical and marine extracts, phytochemicals, and probiotics. Aims of this review were (1) to provide basic concepts including the definition, diagnosis, prevalence, and adverse effects of sarcopenia, (2) to describe possible pathological mechanisms including protein homeostasis imbalance, inflammation, mitochondrial dysfunction, and satellite cells dysfunction, and (3) to analyze recent experimental studies reporting potential biological functions against sarcopenia. A recent literature review for dietary ingredients demonstrated that protein homeostasis is maintained via an increase in the PI3K/Akt pathway and/or a decrease in the ubiquitin-proteasome system. Regulation of inflammation has primarily targeted inhibition of NF-κB signaling. Elevated Pgc-1α or Pax7 expression reverses mitochondrial or satellite cell dysfunction. This review provides the current knowledge on dietary components with the potential to assist sarcopenia prevention and/or treatment. Further in-depth studies are required to elucidate the role of and develop various dietary materials for healthier aging, particularly concerning muscle health.

Sarcopenia and cardiovascular diseases: A systematic review and meta-analysis

Sarcopenia is an age-related disease and is often accompanied by other diseases. Now, many studies have shown that cardiovascular diseases (CVDs) may raise the incidence rate of sarcopenia. Therefore, the purpose of this study was to conduct a systematic review and meta-analysis to investigate the prevalence of sarcopenia in patients with CVDs compared with the general population, defined as relatively healthy non-hospitalized subjects. The databases of PubMed, Embase, Medline and Web of Science were searched for eligible studies published up to 12 November 2022. Two assessment tools were used to evaluate study quality and the risk of bias. Statistical analysis was conducted using STATA 14.0 and R Version 4.1.2. Thirty-eight out of the 89 629 articles retrieved were included in our review. The prevalence of sarcopenia ranged from 10.1% to 68.9% in patients with CVDs, and the pooled prevalence was 35% (95% confidence interval [95% CI]: 28-42%). The pooled prevalence of sarcopenia was 32% (95% CI: 23-41%) in patients with chronic heart failure (CHF), 61% (95% CI: 49-72%) in patients with acute decompensated heart failure (ADHF), 43% (95% CI: 2-85%) in patients with coronary artery disease, 30% (95% CI: 25-35%) in patients with cardiac arrhythmia (CA), 35% (95% CI: 10-59%) in patients with congenital heart disease and 12% (95% CI: 7-17%) in patients with unclassed CVDs. However, in the general population, the prevalence of sarcopenia varied from 2.9% to 28.6% and the pooled prevalence was 13% (95% CI: 9-17%), suggesting that the prevalence of sarcopenia in patients with CVDs was about twice compared with the general population. The prevalence of sarcopenia was significantly higher only in patients with ADHF, CHF and CA compared with the general population. There is a positive correlation between CVDs and sarcopenia. The prevalence of sarcopenia is higher in patients with CVDs than that in the general population. With global aging, sarcopenia has brought a heavy burden to individuals and society. Therefore, it is important to identify the populations with high-risk or probable sarcopenia in order to do an early intervention, such as exercise, to counteract or slow down the progress of sarcopenia.

Electrical impedance myography detects age-related skeletal muscle atrophy in adult zebrafish

Age-related deficits in skeletal muscle function, termed sarcopenia, are due to loss of muscle mass and changes in the intrinsic mechanisms underlying contraction. Sarcopenia is associated with falls, functional decline, and mortality. Electrical impedance myography (EIM)-a minimally invasive, rapid electrophysiological tool-can be applied to animals and humans to monitor muscle health, thereby serving as a biomarker in both preclinical and clinical studies. EIM has been successfully employed in several species; however, the application of EIM to the assessment of zebrafish-a model organism amenable to high-throughput experimentation-has not been reported. Here, we demonstrated differences in EIM measures between the skeletal muscles of young (6 months of age) and aged (33 months of age) zebrafish. For example, EIM phase angle and reactance at 2 kHz showed significantly decreased phase angle (5.3 ± 2.1 versus 10.7 ± 1.5°; p = 0.001) and reactance (89.0 ± 3.9 versus 172.2 ± 54.8 ohms; p = 0.007) in aged versus young animals. Total muscle area, in addition to other morphometric features, was also strongly correlated to EIM 2 kHz phase angle across both groups (r = 0.7133, p = 0.01). Moreover, there was a strong correlation between 2 kHz phase angle and established metrics of zebrafish swimming performance, including turn angle, angular velocity, and lateral motion (r = 0.7253, r = 0.7308, r = 0.7857, respectively, p < 0.01 for all). In addition, the technique was shown to have high reproducibility between repeated measurements with a mean percentage difference of 5.34 ± 1.17% for phase angle. These relationships were also confirmed in a separate replication cohort. Together, these findings establish EIM as a fast, sensitive method for quantifying zebrafish muscle function and quality. Moreover, identifying the abnormalities in the bioelectrical properties of sarcopenic zebrafish provides new opportunities to evaluate potential therapeutics for age-related neuromuscular disorders and to interrogate the disease mechanisms of muscle degeneration.

Skeletal muscle aging and sarcopenia: Perspectives from mechanical studies of single permeabilized muscle fibers

The decline in muscle mass and strength with age is well documented and associated with weakness, decreased flexibility, vulnerability to diseases and/or injuries, and impaired functional restoration. The term sarcopenia has been used to refer to the loss of muscle mass, strength and impaired physical performance with advanced adult age and recently has become a major clinical entity in a super-aged society. To understand the pathophysiology and clinical manifestations of sarcopenia, it is essential to explore the age-related changes in the intrinsic properties of muscle fibers. Mechanical experiments with single muscle fibers have been conducted during the last 80 years and applied to human muscle research in the last 45 years as an in-vitro muscle function test. Fundamental active and passive mechanical properties of skeletal muscle can be evaluated using the isolated permeabilized (chemically skinned) single muscle fiber preparation. Changes in the intrinsic properties of older human single muscle fibers can be useful biomarkers of aging and sarcopenia. In this review, we summarize the historical development of single muscle fiber mechanical studies, the definition and diagnosis of muscle aging and sarcopenia, and age-related change of active and passive mechanical properties in single muscle fibers and discuss how these changes can be used to assess muscle aging and sarcopenia.

Myoblast-derived exosomal Prrx2 attenuates osteoporosis via transcriptional regulation of lncRNA-MIR22HG to activate Hippo pathway

BACKGROUND

Sarcopenia and osteoporosis are common diseases that predominantly affect older individuals. The interaction between muscle and skeleton exerts pivotal roles in bone remodeling. This study aimed to explore the function of myoblast-derived exosomal Prrx2 in osteogenic differentiation and its potential mechanisms.

METHODS

Exosomes were isolated from myogenic differentiated C2C12 cells. qRT-PCR and Western blotting were used to determine target molecule expression. Osteogenic differentiation of BMSCs was evaluated by Alizarin red staining, ALP activity and levels of OCN, OPN, RUNX2, and BMP2. Dual-luciferase reporter assay, RIP, and ChIP assays were performed to verify the interaction between molecules. The nuclear translocation of YAP1 was observed by immunofluorescence staining. In vivo osteoporotic model was established by ovariectomy in mice. Bone loss was examined using HE staining.

RESULTS

Prrx2 expression was elevated in myogenic differentiated C2C12 cells and their exosomes. Myoblast-derived exosomal Prrx2 enhanced osteogenic differentiation of BMSCs. Delivering exosomal Prrx2 directly bond to MIR22HG promoter and promoted its transcription and expression. MIR22HG enhanced expression and nuclear translocation of YAP via sponging miR-128, thus facilitating BMSC osteogenic differentiation. Knockdown of exosomal Prrx2 suppressed osteogenic differentiation, which could be abolished by MIR22HG overexpression. Similarly, miR-128 inhibitor or YAP overexpression reversed the inhibitory effect of MIR22HG depletion or miR-128 mimics on osteogenic differentiation. Finally, myoblast-derived exosomal Prrx2 alleviated osteoporosis in mice via up-regulating MIR22HG and activating the Hippo pathway.

CONCLUSION

Myoblast-derived exosomal Prrx2 contributes to transcriptional activation of MIR22HG to activate YAP pathway via sponging miR-128, thereby facilitating osteogenic differentiation of BMSCs.

Muscle strength and physical performance contribute to and improve fracture risk prediction in older people: A narrative review

Osteoporotic fractures present a major health problem with an increasing prevalence in older people. Fractures are associated with premature mortality, reduced quality of life, subsequent fracture, and increased costs. Hence, it is crucial to identify those at higher risk of fracture. Fracture risk assessment tools incorporated clinical risk factors to improve fracture predictive power over BMD alone. However, fracture risk prediction using these algorithms remains suboptimal, warranting further improvement. Muscle strength and physical performance measurements have been associated with fracture risk. In contrast, the contribution of sarcopenia, the composite condition of low muscle mass, muscle strength and/or physical performance, to fracture risk is unclear. It is uncertain whether this is due to the problematic definition of sarcopenia per se or limitations of the diagnostic tools and cut-off points of the muscle mass component. The recent position statement from the Sarcopenia Definition and Outcomes Consortium confirmed the inclusion of muscle strength and performance in the definition of sarcopenia but not DXA-assessed lean mass. Therefore, clinicians should focus on functional assessment (muscle strength and performance) rather than muscle mass, at least as assessed by DXA, as predictors of fractures. Muscle strength and performance are modifiable risk factors. Resistance exercise improves muscle parameters in the elderly, potentially leading to reduced risk of falls and fractures in the general population and in those who sustained a fracture. Therapists may consider exercise intervention to improve muscle parameters and potentially reduce the risk of fractures. The aim of this review was to explore 1) the contribution of muscle parameters (i.e., muscle mass, strength, and physical performance) to fracture risk in older adults, and 2) the added predictive accuracy of these parameters beyond the existing fracture assessment tools. These topics provide the rationale for investigating strength and physical performance interventions to reduce fracture risk. Most of the included publications showed that muscle mass is not a good predictor of fracture risk, while poor muscle strength and performance are associated with an increased risk of fracture, particularly in men, independent of age, BMD, and other risk factors for fractures. Muscle strength and performance can potentially improve the predictive accuracy in men beyond that obtained by the fracture risk assessment tools, Garvan FRC and FRAX.

Health maintenance through home-based interventions for community-dwelling older people with sarcopenia during and after the COVID-19 pandemic: A systematic review and meta-analysis

BACKGROUND

The COVID-19 pandemic has greatly impacted people's lifestyles and changed the delivery of health interventions, especially interventions for community-dwelling older people with sarcopenia.

OBJECTIVE

To summarize the components and explore the effectiveness of home-based interventions for improving sarcopenia and other health-related outcomes among community-dwelling older people with sarcopenia.

DESIGN

Systematic review and meta-analysis.

METHODS

The Cochrane Library, Scopus, EMBASE, Web of Science, CINAHL, Medline (via PubMed), and PsycINFO were searched for relevant papers published from January 1, 2010 to March 29, 2022. Only papers written in English were included. The modified version of Cochrane's risk-of-bias tool was used to assess the risks of bias in the included studies. The template for intervention description and replication checklist was used to summarize the intervention components. The mean difference (MD) or standard mean difference with a 95 % confidence interval (CI) was used to determine the effect size of studies using the same or different measuring methods. Random-effects models were in meta-analyses to pool the effects of home-based interventions on the included outcomes.

RESULTS

After detailed screening and exclusion, 11 randomized controlled trials including 1136 older people with sarcopenia were included in our analyses. Three categories of home-based interventions were identified: exercise interventions, nutritional interventions, and combined exercise and nutritional interventions. The overall analysis of the outcomes (e.g., appendicular skeletal muscle mass index, lean mass, body fat mass, handgrip strength, and gait speed), showed that the effects of home-based exercise interventions were inconclusive. Compared with passive controls, home-based exercise interventions significantly improved knee extension strength (MD = 0.56 kg, 95 % CI: 0.09, 1.03, p = 0.020) and reduced the time required to complete the Timed Up and Go Test (MD = -1.41 s, 95 % CI: -2.28, -0.54, p = 0.001). Home-based nutritional interventions were effective in improving appendicular skeletal muscle mass (MD = 0.25 kg, 95 % CI: 0.02, 0.49, p = 0.030), gait speed (MD = 0.06 m/s, 95 % CI: 0.03, 0.09, p = 0.0001), and quality of life in terms of both the physical component summary (MD = 13.54, 95 % CI: 0.73, 26.34, p = 0.040) and mental component summary scores (MD = 8.69, 95 % CI: 2.98, 14.41, p = 0.003).

CONCLUSION

Home-based exercise interventions have the potential to improve muscle strength and physical function, while home-based nutritional interventions are effective in increasing muscle mass, physical function, and quality of life. Both of these can be applied at home during and after the COVID-19 pandemic to alleviate sarcopenia and improve health-related outcomes in community-dwelling older people.

"SARCOPENIA MEASURED BY ULTRASOUND IN HOSPITALIZED OLDER ADULTS" (ECOSARC): multi-centre, prospective observational study protocol

BACKGROUND

Measurement of muscle mass and function, and thereafter, screening and diagnosis of sarcopenia, is a challenge and a need in hospitalized older adults. However, it is difficult in complex real-world old patients, because usually they are unable to collaborate with clinical, functional, and imaging testing. Ultrasound measurement of quadriceps rectus femoris (QRF) provides a non-invasive, real-time assessment of muscle quantity and quality, and is highly acceptable to participants with excellent inter-rater and intra-rater variability. However, normative data, protocol standardization, and association with longitudinal outcomes, needs further research and consensus.

METHODS

Prospective exploratory multicenter study in older adults admitted to Acute Geriatric Units (AGUs) for medical reasons. 157 subjects from 7 AGUs of Spain were recruited between May 2019 and January 2022. Muscle ultrasound measurements of the anterior vastus of the QRF were acquired on admission and on discharge, using a previously validated protocol, using a Chieson model ECO2 ultrasound system (Chieson Medical Technologies, Co. Ltd, Wimxu District Wuxi, Jiangsu, China). Measurements included the cross-sectional area, muscle thickness in longitudinal view, intramuscular central tendon thickness, echogenicity, and the presence or absence of edema and fasciculations. Functional, nutritional, and DXA measurements were provided. Clinical follow-up was completed at discharge, and 30 and 90 days after discharge. Variations between hospital admission and discharge ultrasound values, and the relationship with clinical variables, will be analyzed using paired t-tests, Wilcoxon tests, or Mc Nemar chi-square tests when necessary. Prevalence of sarcopenia will be calculated, as well as sensitivity and specificity of ultrasound measurements to determine sarcopenia. Kappa analysis will be used to analyze the concordance between measurements, and sensitivity analysis will be conducted for each participating center.

DISCUSSION

The results obtained will be of great interest to the scientific geriatric community to assess the utility and validity of ultrasound measurements for the detection and follow-up of sarcopenia in hospitalized older adults, and its association with adverse outcomes.

TRIAL REGISTRATION

NCT05113758. Registration date: November 9^th 2021. Retrospectively registered.

Spondyloarthritis and Sarcopenia: Prevalence of Probable Sarcopenia and its Impact on Disease Burden: The Saspar Study

To evaluate the prevalence of probable, confirmed, and severe sarcopenia in spondyloarthritis (SpA), according to the European Working Group on Sarcopenia in Older People 2019 (EWGSOP2) definition. A total of 103 patients (51% women) with SpA, mean age 47.1 ± 13.7 years, were included and compared to 103 age- and sex-matched controls. Grip strength was measured by dynamometry. Body composition was assessed by whole-body densitometry. In SpA patients gait speed was measured by the 4-m-distance walk test and quality of life was evaluated with a specific health-related questionnaire for sarcopenia (SaRQoL®). Twenty-two SpA patients (21%) versus 7 controls (7%) had a low grip strength, i.e., probable sarcopenia (p < 0.01), 15 SpA (15%) patients and 7 controls (7%) had low Skeletal Muscle mass Index (SMI) (ns), respectively, and 5 and 2% of SpA patients and controls had low grip strength and low SMI, i.e., confirmed sarcopenia (ns). All the sarcopenic SpA patients had a low gait speed, i.e., severe sarcopenia. Finally, probable sarcopenic SpA patients had significantly higher C-Reactive Protein (CRP, p < 0.001) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI score, p < 0.01), lower gait speed (p < 0.001), and SarQoL® score (p < 0.001) than SpA patients with normal grip strength. According to EWGSOP2 definition, the prevalence of probable sarcopenia was significantly higher in SpA patients compared to controls. Probable sarcopenia was associated with higher inflammation and disease activity, impaired muscle performance, and quality of life. These results suggest that muscle strength may be a salient hallmark in SpA.

Which intervention is more effective in improving sarcopenia in older adults? A systematic review with meta-analysis of randomized controlled trials

This systematic review aims, however, to determine which intervention is more effective. The skeletal muscle index (SMI), handgrip, and gait speed were used as indicators of improvement, and these effects were compared across six subgroups: combined intervention versus exercise; nutrition or control group; exercise versus nutrition; and exercise or nutrition versus control group. Out of 1596 articles, 32 studies (3063 older adults) were selected and meta-analyzed. Comparing the combined intervention with a control group, the WMD was 0.20 kg/m², 1.56 kg, and 0.08 m/s for SMI, handgrip, and gait speed, respectively, all of which showed a statistically significant improvement. When a combined intervention was compared with exercise and nutrition, the former resulted in improvements in handgrip (WMD 0.38 kg) and gait speed (WMD 0.12 m/s). On comparing exercise and nutrition, there was an improvement in gait speed (0.12 m/s) with exercise alone. On comparing exercise with a control group, only handgrip (WMD 1.74 kg) and gait speed (WMD 0.11 m/s) showed improvement, whereas in the nutrition versus the control group, only the handgrip (WMD 0.90 kg) improved. Although exercise and nutritional therapy together demonstrated improved muscle strength, exercise is recommended for the improvement of physical performance.