Global prevalence of sarcopenia and severe sarcopenia: a systematic review and meta-analysis

Prevalence of Sarcopenia Among Slovenian Older Adults and Associated Risk Factors

Introduction

Sarcopenia is a multifaceted condition affecting between 10 and 16% of the global population, and although multiple classification algorithms exist, no prevalence has been reported for a representative sample of the Slovenian population. Furthermore, multiple behavioural factors, such as malnutrition, physical inactivity, sedentary lifestyle and lower cognitive function, can contribute to the risk of sarcopenia. This study aims to: a) determine sarcopenia prevalence among Slovenian older adults according to different classification algorithms, b) compare the agreement among the algorithms and c) evaluate the relationship between proposed risk factors and sarcopenia.

Methods

654 participants (≥60 years, 30.4% males) have been classified into sarcopenia groups according to eight algorithms, and agreement (Fleiss K) between them was calculated. Additionally, age, sex, nutritional status, physical activity, sedentary levels and cognitive function were assessed as sarcopenia risk/protective factors.

Results

The prevalence of sarcopenia according to EWGSOP2 was 4.1%, ranging from 2.1% to 15.3%, when classified by all eight algorithms. Overall agreement between algorithms was weak (K=.429; 95% CI .414 to .444) with 0.6% of participants classified as sarcopenic by all eight algorithms. Adequate nutrition and physical activity were identified as protective factors, while age, lower cognitive function and sedentary lifestyle were considered risk factors.

Conclusion

Sarcopenia prevalence among the Slovenian general population was lower than in the global population. We can conclude that different sarcopenia algorithms lead to a different prevalence of sarcopenia. It is of great importance to be cautious when comparing prevalences among studies and to further validate the classification algorithms.

Bidirectional association between sarcopenia and depression: A systematic review and meta-analysis

PURPOSE

Recent research has reported a potential bidirectional association between sarcopenia and depression, yet systematic evidence supporting this relationship is still lacking. This study evaluated the bidirectional association of sarcopenia with depression to provide reliable evidence for the development of specific prevention and control strategies.

METHODS

Relevant articles were extracted from PubMed, Embase, Cochrane, and Web of Science from inception to July 4, 2024. Quality was assessed using the Newcastle-Ottawa Scale (NOS) for cohort and case-control studies, and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for cross-sectional studies. Changes in the association between sarcopenia and depression were compared across different study designs, sources of study subjects, and sarcopenia diagnostic criteria by subgroup analyses. Meta-analysis was conducted using R 4.4.1.

RESULTS

Thirty-three original studies involving 119,421 subjects were incorporated into this review. Pooled analysis revealed a significant reciprocal relationship between sarcopenia and depression in community populations. The risk of depression increased when sarcopenia was the exposure factor [OR = 2.40(95 % CI: 1.87, 3.08)]. Conversely, the risk of sarcopenia significantly increased when depression was the exposure factor [OR = 1.90(95 % CI: 1.44, 2.50)]. Additionally, there was a markedly increased risk of sarcopenia when depressive symptoms were the exposure factor [OR = 1.38(95 % CI: 1.25, 1.53)]. Similar conclusions were obtained in patients with other diseases.

CONCLUSIONS

The significant bidirectional association between sarcopenia and depression enhances the prevention, screening, diagnosis, and treatment of depression, thereby improving quality of life and outcomes.

Unraveling the protein-metabolite network of sarcopenia in plasma: A large-scale Mendelian randomization study

BACKGROUND

Some plasma molecules may have an effect on sarcopenia, but it is not fully understood. We aimed to comprehensively explore the causal effects of plasma proteins and metabolites on sarcopenia traits, and to unravel their network.

METHODS

A two-sample Mendelian randomization design was adopted. The levels of 4,907 plasma proteins from 35,559 Icelanders, and 1,400 plasma metabolites from 8,299 Europeans, were set as exposures. Low handgrip strength, appendicular lean mass, and usual walking pace from Europeans were set as outcomes. Inverse-variance weighted (IVW) and four other methods, along with sensitivity analyzes, were performed to estimate the causal effects. Enrichment and pathway analyzes were conducted to present their characteristics. IVW was used to estimate the bidirectional relationships between sarcopenia-related proteins and metabolites, and to visualize them within a network.

RESULTS

We identified 76 relationships between proteins and sarcopenia traits. The absolute values of causal effects (βIVW) ranging from 0.01 to 0.35. IL2, AIF1, GDNF, CXCL13, LRRTM3, and SLPI were the top six proteins ranked by causal effects. Additionally, 22 relationships between metabolites and sarcopenia traits were identified, with absolute values of βIVW ranging from 0.02 to 0.22. Sulfate and serine/pyruvate ratio had the highest values. The network diagram showed some key nodes, such as ISOC1, GSTA1, tryptophan and 5α-androstan-3α,17β-diol monosulfate.

CONCLUSIONS

This work unraveled a molecular network of sarcopenia in plasma for the first time and identified some key proteins and metabolites. It may help to understand the mechanisms of sarcopenia, providing new insights for predicting, diagnosing and treating sarcopenia.

The diagnostic performance of phase angle for sarcopenia among older adults: A systematic review and diagnostic meta-analysis

OBJECTIVE

Phase angle is a promising tool for diagnosing sarcopenia. This study aimed to summarize its diagnostic performance by performing a systematic review and meta-analysis.

METHODS

We conducted a systematic search of PubMed, Web of Science, Embase, and Scopus. The Quality Assessment of Diagnostic Accuracy Studies, Version 2, was used to evaluate the quality of the studies. A bivariate random effects model was employed for data synthesis, and diagnostic performance was reported in terms of pooled sensitivity, specificity, and the area under the summary receiver operating characteristic curve (AUC). Additionally, meta-regression, subgroup analyses, and sensitivity analyses were performed.

RESULTS

A total of 15 studies were included in this meta-analysis, involving 4,063 participants. The overall risk of bias in the included studies was high. The meta-analysis revealed that the pooled sensitivity and specificity across all studies were 0.74 [95 % confidence interval (CI): 0.71-0.78] and 0.75 (95 % CI: 0.70-0.79), respectively, with an AUC of 0.79 (95 % CI: 0.76-0.83). Meta-regression indicated that study design, country, population, sex-specificity, and age may influence the diagnostic performance of phase angle. The optimal diagnostic performance was observed in the cut-off interval of 4.20 to 4.50°.

CONCLUSION

The phase angle demonstrated moderate diagnostic performance for sarcopenia, and the possible cut-off interval is 4.20 to 4.50 °. However, large-scale, multicenter prospective studies are necessary to assess its clinical applicability at specific cut-off values.

An Attention-Aware Multi-Task Learning Framework Identifies Candidate Targets for Drug Repurposing in Sarcopenia

BACKGROUND

Sarcopenia presents a pressing public health concern due to its association with age-related muscle mass decline, strength loss and reduced physical performance, particularly in the growing older population. Given the absence of approved pharmacological therapies for sarcopenia, the need to discover effective pharmacological interventions has become critical.

METHODS

To address this challenge and discover new therapies, we developed a novel Multi-Task Attention-aware method for Multi-Omics data (MTA-MO) to extract complex biological insights from various biomedical data sources, including transcriptome, methylome and genome data to identify drug targets and discover new therapies. Additionally, MTA-MO integrates human protein-protein interaction (PPI) networks and drug-target networks to improve target identification. The novel method is applied to a multi-omics dataset that included 1055 participants aged 20-50 (mean (± SD) age 36.88 (± 8.64)), comprising 37.82% African-American and 62.18% Caucasian/White individuals. Physical activity levels were self-reported and categorized into three groups: ≥ 3 times/week, < 3 times/week and no regular exercise. Mean (± SD) measures for grip strength, appendicular lean mass (ALM), exercise frequency and smoking status (no/yes, n (%)) were 38.72 (± 8.93) kg, 28.65 (± 4.63) kg, 4.31 (± 1.79) and 30.81%/69.19%, respectively. Significant differences (p < 0.05) were found between groups in age, ALM, smoking, and consumption of milk, alcohol, beer and wine.

RESULTS

Using the MTA-MO method, we identified 639 gene targets, and by analysing PPIs and querying public databases, we narrowed this list down to seven potential hub genes associated with sarcopenia (ESR1, ATM, CDC42, EP300, PIK3CA, EGF and PTK2B). These findings were further validated through diverse levels of pathobiological evidence associated with sarcopenia. Gene Ontology and KEGG pathways analysis highlighted five key functions and signalling pathways relevant to skeletal muscle. The interaction network analysis identified three transcriptional factors (GATA2, JUN and FOXC1) as the key transcriptional regulators of the seven potential genes. In silico analysis of 1940 drug candidates identified canagliflozin as a promising candidate for repurposing in sarcopenia, demonstrating the strongest binding affinity to the PTK2B protein (inhibition constant 6.97 μM). This binding is stabilized by hydrophobic bonds, Van der Waals forces, pi-alkyl interactions and pi-anion interactions around PTK2B's active residues, suggesting its potential as a therapeutic option.

CONCLUSIONS

Our novel approach effectively integrates multi-omics data to identify potential treatments for sarcopenia. The findings suggest that canagliflozin could be a promising therapeutic candidate for sarcopenia.

TLR/NLRP3 inflammasome signaling pathways as a main target in frailty, cachexia and sarcopenia

Mobility disability is a common condition affecting older adults, making walking and the performance of activities of daily living difficult. Frailty, cachexia and sarcopenia are related conditions that occur with advancing age and are characterized by a decline in muscle mass, strength, and functionality that negatively impacts health. Chronic low-grade inflammation is a significant factor in the onset and progression of these conditions. The toll-like receptors (TLRs) and the NLRP3 inflammasome are the pathways of signaling that regulate inflammation. These pathways can potentially be targeted therapeutically for frailty, cachexia and sarcopenia as research has shown that dysregulation of the TLR/NLRP3 inflammasome signaling pathways is linked to these conditions. Activation of TLRs with pathogen-associated molecular patterns (PAMPs or DAMPs) results in chronic inflammation and tissue damage by releasing pro-inflammatory cytokines. Additionally, NLRP3 inflammasome activation enhances the inflammatory response by promoting the production and release of interleukins (ILs), thus exacerbating the underlying inflammatory mechanisms. These pathways are activated in the advancement of disease in frail and sarcopenic individuals. Targeting these pathways may offer therapeutic options to reduce frailty, improve musculoskeletal resilience and prevent or reverse cachexia-associated muscle wasting. Modulating TLR/NLRP3 inflammasome pathways may also hold promise in slowing down the progression of sarcopenia, preserving muscle mass and enhancing overall functional ability in elderly people. The aim of this review is to investigate the signaling pathways of the TLR/NLRP3 inflammasome as a main target in frailty, cachexia and sarcopenia.

Protein supplementation alone or combined with exercise for sarcopenia and physical frailty: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Sarcopenia and physical frailty are age-related syndromes characterized by progressive loss of muscle mass and function, significantly impacting mortality and quality of life in older adults. This systematic review evaluated the effectiveness of protein supplementation interventions for these conditions.

METHODS

We systematically searched Medline, CENTRAL, and Ichushi Web from January 2000 to March 2023, with additional manual searching extended to March 2024. Randomized controlled trials investigating protein supplementation, alone or combined with exercise, in adults aged ≥65 years with sarcopenia or physical frailty were included. The primary outcomes were changes in muscle mass, strength, and physical performance.

RESULTS

The systematic literature search identified 1,506 records through database searching (Medline: 357, CENTRAL: 275, Ichushi Web: 639) and 235 additional records through hand searching. Finally, 13 randomized controlled trials (n=1,057) met the inclusion criteria. Combined protein and exercise interventions demonstrated significant improvements in skeletal muscle index (MD = 0.89 kg/m², 95 % CI: 0.45 to 1.33) and handgrip strength (MD: +2.64 kg, 95 % CI: +0.75 to +4.53) compared to exercise alone. Protein supplementation alone showed modest benefits in muscle strength but limited effects on physical performance. No serious adverse events were reported.

CONCLUSIONS

While protein supplementation combined with exercise shows promising effects on muscle mass and strength in older adults with sarcopenia or physical frailty, the evidence quality was consistently rated as very low. Further high-quality trials are needed to establish optimal supplementation strategies.

REGISTRATION

PROSPERO: CRD42023408529.

Sarcopenic obesity and brain health: A critical appraisal of the current evidence

Sarcopenic obesity (SO) is a body composition phenotype derived from the simultaneous presence in the same individual of an increase in fat mass and a decrease in skeletal muscle mass and/or function. Several protocols for the diagnosis of SO have been proposed in the last two decades making prevalence and disease risk estimates of SO heterogeneous and challenging to interpret. Dementia is a complex neurological disorder that significantly impacts patients, carers and healthcare systems. The identification of risk factors for early cognitive impairment and dementia is key to mitigating the forecasted trends of a 2-fold increase in dementia case numbers over the next two decades worldwide. Excess adiposity and sarcopenia have both been independently associated with risk of cognitive impairment and dementia. Whether SO is associated with a greater risk of cognitive impairment and dementia is currently uncertain. This review critically appraises the current evidence on the association between SO with cognitive outcomes and dementia risk. It also discusses some of the putative biological mechanisms that may link the SO phenotype with alteration of brain functions.

Prevalence of sarcopenia in Asian older adults: A comparison of nine diagnostic criteria across different regions

OBJECTIVE

This study aimed to compare sarcopenia prevalence in older adults using nine diagnostic criteria from different regions to assess how these guidelines influence prevalence rates within the same population. Additionally, we analyzed variations across subgroups to identify factors contributing to prevalence differences.

METHODS

A total of 1760 participants aged 65-99 were enrolled. Bioelectrical impedance analysis was used to assess muscle mass, while muscle strength and physical performance were evaluated using grip strength, gait speed, and the repeated chair stands test. Sarcopenia prevalence was determined based on definitions provided by ESPEN (European Society for Clinical Nutrition and Metabolism), EWGSOP (European Working Group on Sarcopenia in Older People), IWGS (International Working Group on Sarcopenia), SCWD (Society for Sarcopenia, Cachexia, and Wasting Disorders), AWGS (Asian Working Group for Sarcopenia), FNIH (Foundation for the National Institutes of Health), and SDOC (Sarcopenia Definitions and Outcomes Consortium). Additionally, prevalence rates were assessed across subgroups based on age, sex, and BMI categories.

RESULTS

Sarcopenia prevalence varied from 4.8 % (n = 79), based on the FNIH criteria, to 16.1 % (n = 261), according to the EWGSOP criteria. Among females, higher prevalence rates were observed using the ESPEN, AWGS, and EWGSOP2 criteria, while the FNIH criteria indicated a higher prevalence in males. Prevalence increased with age, especially in those aged 85 and older. Lower BMI was associated with higher sarcopenia prevalence according to most criteria, except the FNIH and ESPEN.

CONCLUSION

The notable variability in sarcopenia prevalence across different diagnostic criteria highlights the need for population-specific guidelines. Refining diagnostic criteria to address demographic variations could enhance the accuracy and applicability of sarcopenia assessments. Future studies should aim to further tailor diagnostic approaches and interventions to meet the needs of diverse populations.

Causal association of sarcopenia-related traits with brain cortical structure: a bidirectional Mendelian randomization study

BACKGROUND

Patients with sarcopenia often experience cognitive decline, affecting cortical structures, but the causal link remains unclear. We used bidirectional Mendelian randomization (MR) to explore the relationship between sarcopenia-related traits and cortical structure.

METHODS

We selected genetic variables from genome-wide association study data. Three different MR methods were used: inverse-variance weighted analysis, MR-Egger regression, and the weighted median test. For significant estimates, we further conducted Cochran's Q test, MR-Egger intercept test, leave-one-out analyses, and MR-PRESSO to assess heterogeneity.

RESULTS

In forward MR analysis, appendicular lean mass (ALM) decreased the thickness (TH) of lateral occipital gyrus and increased the TH of pars opercularis gyrus (β = -0.0079 mm, 95% CI: -0.0117 mm to -0.0041 mm, P < 0.0001; β = 0.0080 mm, 95% CI: 0.0042 mm to 0.0117 mm, P < 0.0001). In reverse MR analysis, a significant negative correlation was found between the TH of bankssts and ALM, while positive correlations were observed between the TH of frontal pole, rostral anterior cingulate, temporal pole, and ALM. The TH of temporal pole was positively correlated with right hand grip strength (HGS-R) (β = 0.1596 mm, 95% CI: 0.1349 mm to 0.1843 mm, P < 0.0001), and the TH of pars triangularis was positively correlated with left-hand grip strength (HGS-L) (β = 0.3251 mm, 95% CI: 0.2339 mm to 0.4163 mm, P < 0.0001).

CONCLUSIONS

Sarcopenia-related traits and cortical structure have bidirectional effects, supporting the muscle-brain axis theory. This links sarcopenia to neurocognitive diseases and provides new strategies for the prevention and intervention of both sarcopenia and cognitive decline.

The association between sedentary lifestyle and the prevalence of sarcopenia with the mediation role of systematic inflammation index, 25-hydroxyvitamin D, and testosterone: A nationwide cross-sectional study

BACKGROUND

While there is some evidence of the association between sedentary behavior and sarcopenia risk, it remains unclear whether systematic inflammation index (SII), 25(OH)D, and testosterone can mediate this association. This study aims to investigate whether sedentary behavior is associated with the prevalence of sarcopenia in the US population and further examine its potential mediators which have not been thoroughly explored, thereby presenting a novel approach to understanding the mechanism between sedentary behavior and sarcopenia.

METHODS

We conducted a cross-sectional study involving a representative sample of the US national population of 9902 adults aged 18 years or older from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. The participants with sarcopenia were identified by Dual-energy X-ray (DXA) absorptiometry. Weighted multivariable logistic regressions based on the complex survey designs were used to explore the associations between a sedentary lifestyle and the risk of sarcopenia and restricted cubic spline (RCS) regression was used to examine the non-linear association. Causal mediation analysis using the quasi-Bayesian Monte Carlo method was applied to identify the mediating role of SII, 25(OH)D, and testosterone as potential mediators.

RESULTS

A total of 358 participants (3.6 %) had sarcopenia. Compared to those in the lowest quartile of sedentary time, participants in the highest quartile had a hazard ratio of 1.631 (95 % CI: 1.162 to 2.289) for the prevalence of sarcopenia. A non-linear relationship (P for non-linearity <0.001) between sedentary time and the risk of sarcopenia was observed using the RCS method. The odds ratio for sarcopenia was highest (OR = 3.427) when the sedentary time was 1080 min daily. Furthermore, SII, 25(OH)D, and testosterone showed a significant mediation in the association between sedentary time and sarcopenia risk, with a mediation effect of 3.39 %, 10.3 %, and 8.56 %, respectively.

CONCLUSIONS

This study demonstrated novel findings of the association between sedentary behavior and sarcopenia in the US population. Our study found that sedentary time was associated with the prevalence of sarcopenia. Vitamin D, SII, and testosterone served as mediating factors in the association of sedentary time with the risk of sarcopenia.

Relationships of sarcopenia symptoms and dietary patterns with lung cancer risk: a prospective cohort study

Background: Few studies focused on the effects of sarcopenia on lung cancer in the general population and optimizing nutritional intake may be a feasible way to manage sarcopenia. We sought to systematically investigate the associations of sarcopenia symptoms with lung cancer incidence and mortality in the general population, and whether dietary patterns could modify these risks. Methods: A total of 361 763 participants (mean age: 56.2 years; and men: 46.7%) were included in this prospective UK Biobank study. Sarcopenia symptoms (low handgrip strength, low muscle mass and slow walking pace) were determined according to European Working Group of Sarcopenia in Older People 2 (EWGSOP2) criteria. Individuals without any of the three sarcopenia symptoms were classified as the normal control group. Based on the baseline data from food frequency questionnaires, primary dietary patterns were identified through principal component analysis. Cox proportional hazards models were used to examine associations between sarcopenia symptoms as well as dietary patterns and lung cancer. Then we explored the joint effects of sarcopenia symptoms and dietary patterns on lung cancer risk. Results: A total of 3532 incident lung cancer cases and 2073 deaths were documented during a median follow-up of 12 years. All the sarcopenia symptoms were associated with a higher risk of lung cancer incidence than the normal control group, especially in people aged <60 (Pinteraction < 0.05). Particularly, a stronger association was observed for slow walking pace with incidence (hazard ratio [HR]: 1.49, 95% confidence interval [CI]: 1.34-1.65) and mortality (HR: 1.54, 95% CI: 1.35-1.75) of lung cancer. Higher adherence to the wholegrain pattern was associated with a greater reduction in the risk of lung cancer incidence (HRQ4vs.Q1: 0.71, 95% CI: 0.65-0.79) and mortality (HRQ4vs.Q1: 0.68, 95% CI: 0.60-0.77). The joint analysis demonstrated that the risk of lung cancer-related outcomes associated with low handgrip strength gradually reduced as the quartile of wholegrain pattern scores increased (Ptrend < 0.05). Conclusions: Our study indicated that individuals with sarcopenia symptoms suffered a higher risk of lung cancer incidence and mortality even in younger age. A diet abundant in whole grains may help to improve sarcopenia symptoms and reduce adverse lung cancer-related outcomes associated with low handgrip strength.

Opportunistic muscle density assay during CT lung cancer screening for low muscle quality evaluation in older adults: a multicenter study

BACKGROUND

Intramuscular adiposity, which can be reflected by muscle computed tomography (CT) attenuation, may be a marker of sarcopenia. This study aimed to investigate muscle attenuation across the life course and thresholds of muscle attenuation for evaluating low muscle quality in older adults.

METHODS

This retrospective multicenter study included 9701 subjects aged 20 years and older who underwent CT lung cancer screening from 2019 to 2021 at our institutions in cohort 1. Muscle attenuation (Hounsfield units [HUs]) of the bilateral erector spinae and spleen attenuation at the middle level of the T11 vertebra were measured. The T score, which is analogous to that used to define osteoporosis, was calculated on the basis of absolute muscle attenuation and the muscle‒spleen ratio (M/S). A T score < -2.5 was used to define low muscle density. The cutoff points for muscle CT attenuation and M/S were subsequently calculated to define low muscle density. Another cohort (cohort 2) of 2006 subjects aged 50 years or older was included to explore the association between low muscle quality and vertebral compression fracture (VCF).

RESULTS

The mean [SD] age of cohort 1 was 51.8 [15.5] years, and 5896 [60.8%] men were included. The mean [SD] age of cohort 2 was 62.4 [9.6] years, and 1162 [57.9%] men were included. Multiple linear regression analysis revealed that age was associated with muscle CT attenuation (β = -0.19, 95% confidence interval (CI): -0.21 to -0.18) and the M/S ratio (β = -0.004, 95% CI: -0.004 to -0.003). The prevalence of low muscle density was dependent on the cutoff point and increased with age. A cutoff point of 32 HU for women and 37 HU for men and an M/S of 0.65 for women and 0.75 for men were used to define low muscle density. Low muscle density defined by those cutoff points was associated with the risk of VCF [muscle attenuation: adjusted hazard ratio (aHR) = 0.422 (95% CI: 0.256-0.696) for women; aHR = 0.391 (95% CI: 0.173-0.883) for men; M/S: aHR = 0.40 (95% CI: 0.23-0.68) for women; aHR = 0.23 (95% CI: 0.09-0.58) for men].

CONCLUSION

Muscle density decreases with age. The muscle attenuation of 32 HU for women and 37 HU for men, an M/S of 0.65 for women and 0.75 for men, may be used to define low muscle density.

Low serum HSPA12B levels are associated with an increased risk of sarcopenia in a Chinese population of older adults

Sarcopenia is a geriatric syndrome characterized by progressive loss of muscle mass and function. Heat shock protein (HSP) A12B is essential for angiogenesis and endothelial function. However, the association of HSPA12B levels with sarcopenia remains unclear. A total of 936 community-dwelling elderly people were recruited, and serum HSPA12B was measured by enzyme-linked immunosorbent assay. Appendicular skeletal muscle mass index (ASMI), grip strength, and gait speed were taken to assess sarcopenia. We found that serum HSPA12B levels in patients with sarcopenia (median [interquartile range] = 182.15 [137.58-225.86] ng/mL) were lower than those in elderly people without sarcopenia (228.96 [193.03-292.93] ng/mL, P < 0.001). Receiver operating characteristic curve analysis indicated that the optimal cut-off value of serum HSPA12B level for predicting sarcopenia was 185.50 ng/mL, with a sensitivity of 52.6% and a specificity of 80.8% (area under curve = 0.742, 95% confidence interval [CI] = 0.711-0.772, P < 0.001). Moreover, serum HSPA12B concentration was positively correlated with ASMI (r = 0.354, P < 0.001), grip strength (r = 0.381, P < 0.001), and gait speed (r = 0.169, P < 0.001). Multivariate logistic regression analysis showed that decreased serum HSPA12B levels (<185.50 ng/mL) were a risk factor for increased risk of sarcopenia (adjusted odds ratio = 4.335, 95% CI = 3.136-5.993, P < 0.001). In addition, serum HSPA12B level was also positively correlated with serum levels of angiogenesis markers, vascular endothelial growth factor (r = 0.080, P = 0.014), and angiopoietin-1 (r = 0.108, P = 0.001). In summary, our results indicate that low serum HSPA12B level is associated with an increased risk of sarcopenia in the elderly, suggesting a potential role of HSPA12B in the development of sarcopenia.

Prevalence and influencing factors of sarcopenia among older adults in rural coastal areas of Ningbo City

Sarcopenia has become a critical health concern in the global older population. However, limited studies have investigated the epidemiological characteristics and potential risk factors of sarcopenia in older individuals residing in rural coastal areas of China. This cross-sectional study involving sarcopenia screening was conducted in Ningbo City, including body composition measurements, and questionnaire surveys. Sarcopenia was diagnosed using the criteria outlined in the Asian Working Group for Sarcopenia 2019 Consensus. A total of 902 older adults aged ≥ 60 years (average age: 69.76 years) were included using a two-stage random sampling method from three villages in Ningbo. The prevalence of sarcopenia was 11.53%, with men (16.36%) exhibiting higher rates than women (7.93%). Multivariate logistic regression analysis identified age (odds ratio [OR]: 6.708, 95% confidence interval [CI]: 2.520-17.855), stroke (OR: 9.232, 95% CI: 1.917-44.447), and waist circumference (OR: 1.095, 95% CI: 1.030-1.165) as factors positively correlated with the occurrence of sarcopenia. Conversely, body mass index (OR: 0.347, 95% CI: 0.270-0.445) was negatively correlated with sarcopenia development. These findings underscore the need for specific health education, the collaborative prevention of comorbidities, and active screening for sarcopenia in the older population to reduce its disease burden.

Sex disparity in the association between alcohol consumption and sarcopenia: a population-based study

Background

Previous studies have shown inconsistent findings regarding the association of alcohol consumption with sarcopenia. Therefore, this study comprehensively investigated the association of alcohol consumption with sarcopenia in a nationally representative sample of US adults.

Methods

This population-based study included adults aged 18 years and older from the National Health and Nutrition Examination Survey (NHANES) III. Alcohol exposure was defined as daily alcohol intake, alcohol drinking history, number of drinking days per week, and frequency of binge drinking days per month. Weighted logistic regressions were used to determine associations.

Results

Four cohorts were selected from the NHANES III: cohort 1 (n = 7,592), cohort 2 (n = 12,060), cohort 3 (n = 7,608), and cohort 4 (n = 7,649), corresponding to alcohol exposure categories of daily alcohol intake, drinking history, number of drinking days per week, and frequency of binge drinking days per month. In the full model, the risk of sarcopenia was significantly associated with mild (odds ratio [OR]: 1.65; 95% confidence interval [CI]: 1.08-2.51), moderate (OR: 2.04; 95% CI: 1.12-3.71), and heavy drinkers (OR: 2.42; 95% CI: 1.17-4.97) compared to nondrinkers. There was an association between the development of sarcopenia and current drinkers (OR: 1.69; 95% CI: 1.12-2.56) but not former drinkers (OR: 1.21; 95% CI: 0.88-1.66). Compared to nondrinkers, an increased risk of developing sarcopenia was observed in participants who consumed alcohol 2 days (OR: 2.36; 95% CI: 1.40-3.99) or > 2 days (OR: 1.84; 95% CI: 1.10-3.07) per week, and those who engaged in binge drinking for ≤1 day per month (OR: 1.68; 95% CI: 1.09-2.60) or > 1 day per month (OR: 2.10; 95% CI: 1.10-4.01). Sensitivity analyses based on different definitions of sarcopenia yielded similar results. Stratified analyses revealed that these associations were present in females but not males.

Conclusion

Alcohol intake was associated with an increased risk of sarcopenia in all individuals, with this association being primarily observed in females rather than males.

Effects of 12-month physical and cognitive training on sarcopenia determinants in older adults: a subgroup analysis of a randomised clinical trial

BACKGROUND

Low physical activity is a major risk for sarcopenia. Whether training according to physical activity guidelines accompanied with cognitive training is effective on sarcopenia, remains unclear.

AIMS

We investigated whether the effects of 12-month physical and cognitive training (PTCT) and physical training (PT) on grip and knee extension strength, muscle mass, and walking speed differed between older adults with and without sarcopenia.

METHODS

Community-dwelling older adults (N = 314, mean age 74.5 ± 3.8 years, 60% women) who did not meet physical activity guidelines were randomized to PTCT and PT groups. PT for both groups included supervised and home-based multicomponent physical training. Cognitive training (CT) included computer-based exercises for executive functioning. Sarcopenia was determined according to the European Working Group on Sarcopenia in Older People 2019 criteria. Generalized estimation equation analysis were conducted.

RESULTS

Compared to PT, PTCT had no additive effect on strength, muscle mass, or walking speed in participants with or without sarcopenia. In pooled data (PT + PTCT) change in the grip strength was greater in sarcopenia (n = 49) group compared to non-sarcopenia (n = 264) group (interaction, p =.014). Both groups improved knee extension strength, and walking speed, but no statistically significant difference between the groups were observed. Muscle mass did not change in either group.

CONCLUSION

Physical training according to physical activity recommendations improves muscle strength, walking speed, and maintains muscle mass in sarcopenia. Additional cognitive training had no benefits on these outcomes.

TRIAL REGISTRATION NUMBER

ISRCTN52388040 and date of registration 20/1/2017.

Association of social frailty, sarcopenia, and oral frailty with depressive symptoms in Chinese older adults: a cross-sectional study

BACKGROUND

Depressive symptoms are a serious health issue that can cause profound, lifelong suffering for people who are affected by it. This study aimed to evaluate the effect of sarcopenia, oral frailty, and social frailty on depressive symptoms among Chinese participants aged ≥ 60 years old in China.

METHODS

This research utilized a cross-sectional design and used convenience sampling to select participants from Anhui Province, China. Demographic questionnaire, SARC-F (Strength, Assistance with walking, Rising from a chair, Climbing stairs, and Falls), OFI-8 (Oral Frailty Index-8), the HALFT (Help, Participation, Loneliness, Financial, Talk) scale, and PHQ-9 (Patient Health Questionnaire-9) were used to conduct the survey. A chi-square test was performed to evaluate the differences between categorical variables, spearman correlation analysis was used to find the correlation between depressive symptoms and factors. Four regression models were set up to evaluate the effect of factors on depressive symptoms and select the appropriate adjustment variables.

RESULTS

Of 1453 participants, 33.5% had sarcopenia, 51.4% had oral frailty, 31.5% had pre-social frailty, 14.5% had social frailty, and 32.2% had depressive symptoms. Spearman correlation analysis indicated that depressive symptoms significantly correlated with sarcopenia (r = 0.415), oral frailty (r = 0.282), and social frailty (r = 0.410). In crude analysis, sarcopenia (OR = 0.179, 95%CI 0.141-0.227), oral frailty (OR = 3.946, 95%CI 3.101-5.021), pre-social frailty (OR = 4.449, 95%CI 3.401-5.818), and social frailty (OR = 12.552, 95%CI 8.833-17.837) were significantly associated with depressive symptoms in older adults. After adjusting for the covariates, sarcopenia (OR = 4.301, 95%CI 3.322-5.569), oral frailty (OR = 3.136, 95%CI 2.430-4.046), pre-social frailty (OR = 3.664, 95%CI 2.775-4.836) and social frailty (OR = 9.488, 95%CI 6.560-13.723) were significantly associated with depressive symptoms. (P <0.05).

CONCLUSION

This research indicated that sarcopenia, oral frailty, pre-social frailty, and social frailty, were significant and positively associated with depressive symptoms. These results provide clinicians with a reference for identifying high-risk older adults and give public health policymakers a scientific approach to taking targeted interventions. Future research should further explore the two-way relationship between these factors and depressive symptoms and assess the effectiveness of different interventions. This will help to improve the quality of life and mental health.

Muscle Dysfunction and Physical Recovery After Critical Illness

During critical illness, patients experience significant and rapid onsets of muscle wasting and dysfunction with loss of strength, mass, and power. These deficits often persist long after the ICU, leading to impairments in physical function including reduced exercise capacity and increased frailty and disability. While there are numerous studies describing the epidemiology of impaired muscle and physical function in the ICU, there are significantly fewer data investigating mechanisms of prolonged and persistent impairments in ICU survivors. Additionally, while several potential clinical risk factors associated with poor physical recovery have been identified, there remains a dearth of interventions that have effectively improved outcomes long-term among survivors. In this article, we aim to provide a thorough, evidence-based review of the current state of knowledge regarding muscle dysfunction and physical function after critical illness with a focus on post-ICU and post-hospitalization phase of recovery.

Lipid peroxidation and sarcopenia: molecular mechanisms and potential therapeutic approaches

Sarcopenia is an age-related condition characterized by the progressive loss of skeletal muscle mass and strength. With the global aging population, its incidence is rapidly increasing. Lipid peroxidation is a critical biochemical process that generates reactive oxygen species (ROS), leading to the destruction of muscle cell structure and function. It plays a pivotal role in the onset and progression of sarcopenia. This review summarizes the mechanisms by which lipid peroxidation contributes to sarcopenia, with a focus on its regulatory effects on cell membrane damage, mitochondrial dysfunction, and cell death. In addition, we discuss the protective role of antioxidant factors such as GPX4 (glutathione peroxidase 4) and antioxidant peptides like SS peptides in mitigating lipid peroxidation and delaying the progression of sarcopenia. Finally, the potential of various strategies, including natural compounds, supplements, natural extracts, and lifestyle interventions, in inhibiting lipid peroxidation and promoting muscle health is explored.

Relationship of α-Klotho with Frailty Index and Sarcopenia: A Bidirectional Mendelian Randomization Study

Previous studies have established associations between α-Klotho and frailty or sarcopenia; however, the causal nature of these relationships remains unclear. This study investigates the causal effects of α-Klotho on frailty and sarcopenia-related traits using Mendelian randomization (MR). Genetic instruments for circulating α-Klotho concentrations, frailty index (FI), low grip strength (LGS), appendicular lean mass (ALM), and walking pace were developed based on data from large genome-wide association studies. Two-sample MR analyses were performed, supplemented by sensitivity analyses to ensure the robustness of the findings. Reverse MR analyses were also conducted to explore potential reverse causation. The findings demonstrated an inverse causal relationship of circulating α-Klotho levels with FI (β = -0.020, 95% confidence interval [95% CI] = -0.036 to -0.004; p = 0.017) and LGS (β = -0.033, 95% CI = -0.061 to -0.004; p = 0.023). However, no causal relationship was observed between circulating α-Klotho levels and ALM or walking pace. Additionally, no evidence of reverse causation was identified between FI or sarcopenia-related traits and circulating α-Klotho levels. In conclusion, this MR analysis establishes an inverse causal relationship of circulating α-Klotho levels with both FI and LGS.

Reference Values of Handgrip and Lower Extremity Strength for Vietnamese Men and Women: The Vietnam Osteoporosis Study

BACKGROUND

Falls and sarcopenia are significant public health issues in Vietnam. Despite muscle strength being a critical predictor for these conditions, reference data on muscle strength within the Vietnamese population are lacking.

PURPOSE

To establish the reference ranges for muscle strength among Vietnamese individuals.

METHODS

The study involved 4096 individuals, including 1419 men and 2677 women aged 18 years and above, from the Vietnam Osteoporosis Study. Muscle strength was assessed using a Baseline hand dynamometer for handgrip strength and a Back-Leg-Chest dynamometer for leg strength. We calculated mean values, standard deviations, interquartile ranges, and peak muscle strength (pMS) for both handgrip and leg strength across various ages. Reference curves were created with the Generalised Additive Model for Location Scale and Shape, and polynomial regression models were employed to analyse the relationship between muscle strength and age.

RESULTS

Advancing age was significantly associated with lower muscle strength. Peak muscle strength typically occurred between ages 30 and 40, with earlier peaks in women, especially in leg strength. Men consistently showed higher muscle strength than women, with variations depending on the measurement site. Specifically, average handgrip strength was 36.4 kg ± 8.4 (mean ± SD) for men and 23.2 kg ± 6.0 for women (p < 0.001). Leg strength averaged 63.9 kg ± 27.2 for men and 29.5 kg ± 13.9 for women (p < 0.001). Additionally, we produced a percentile chart illustrating muscle weakness ranges based on the 25th percentile of muscle strength and the appendicular skeletal muscle mass index (ASMI) for the Vietnamese population.

CONCLUSION

These data provide reference ranges for evaluating muscle strength in the Vietnamese population, offering crucial insights for identifying individuals at risk of falls or sarcopenia in clinical settings.

The association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and sarcopenia: A cross-sectional study

BACKGROUND

The non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) is a newly developed lipid parameter that's used to evaluate cardiovascular disease risk. However, its association with sarcopenia risk has not been explored before.

METHODS

Data on NHHR and sarcopenia were based on the secondary analysis of the years 2011-2018 of National Health and Nutrition Examination Survey (NHANES) dataset. NHHR was nature log-transformed (LnNHHR) to achieve a normal distribution. A multivariate logistic regression and a restricted cubic spline (RCS) model adjusted for associated factors were utilized to evaluate the correlation between NHHR and sarcopenia. Subgroup and sensitivity analyses were conducted to verify the robustness of the findings.

RESULTS

The study cohort comprised 7069 participants, of whom 6497 (91.91 %) were sarcopenia-free, and 572 (8.09 %) exhibited sarcopenia. A significant increase in NHHR was observed in the sarcopenia group compared to the non-sarcopenic group (P < 0.001). Multivariate logistic regression analysis revealed that sarcopenia was independently linked to NHHR [odds ratio (OR): 1.394, P = 0.007]. A linear relationship was identified between NHHR and sarcopenia risk (Pnon-linear = 0.108). Interaction analysis indicated that the relationship between NHHR and sarcopenia risk was not significantly modified by gender, sex, poverty income ratio, education, smoking status, or race.

CONCLUSION

NHHR was significantly associated with an elevated risk of sarcopenia among U.S. adults. Further research is warranted to elucidate the underlying physiological mechanisms through which NHHR influences sarcopenia development.

Associations of nutritional intake and inflammatory factors with sarcopenia in community-dwelling older adults: a cross-sectional study

PURPOSE

Sarcopenia is an age-related disease that is related to nutritional intake and chronic low-grade inflammation. The aim of this study was to investigate the association of dietary intake, inflammatory markers and sarcopenia among the community-dwelling older adults.

METHODS

A total of 1001 older adults aged 60 and above were recruited. According to the criteria established by the Asian Working Group for Sarcopenia 2019, this paper assessed the presence of sarcopenia and using a Food Frequency Questionnaire to evaluate daily dietary intake. Serum levels of inflammatory markers were measured using the ELISA method.

RESULTS

A total of 1001 participants took part in the study (mean 70.6 years), comprising 396 males and 605 females, the prevalence of sarcopenia was 19.6%. Multivariate analysis revealed that high levels of leucine, methionine, threonine, histidine, aspartic acid, calcium, zinc, and vitamin C were associated with a lower risk of sarcopenia. Higher dietary inflammatory index scores were associated with a higher risk of sarcopenia (OR  1.67, 95% CI 1.12-2.47). Higher tumor necrosis factor-like weak inducer of apoptosis (TWEAK) (OR 1.04, 95% CI 1.02-1.07) was associated with a higher risk of sarcopenia, and a lower skeletal muscle mass, strength, and physical function. Conversely, higher insulin-like growth factor-1 (IGF-1) (OR 0.83, 95% CI 0.74-0.94) and glutathione S-transferase (GST) (OR 0.75, 95% CI 0.61-0.91) were associated with a lower risk of sarcopenia.

CONCLUSIONS

This cross-sectional study revealed alterations in amino acid and micronutrient intake among older adults with sarcopenia. The levels of TWEAK were associated with an increased risk of sarcopenia, whereas IGF-1 and GST were associated with a reduced risk of sarcopenia.

The BET inhibitor JQ1 targets fat metabolism and counteracts obesity

INTRODUCTION

Obesity, one of the most frequent health problems in the adult population, is a condition characterized by excessive white adipose tissue accumulation and accompanied by the increased risk to develop other disorders such as type II diabetes, cardiovascular disorders, physical disability, frailty and sarcopenia. Total fat mass frequently increases during aging, often coexisting with sarcopenia, thus resulting in an emerging condition defined sarcopenic obesity (SO). Our previous data demonstrated the relevant role of the bromo and extra-terminal domain (BET) proteins inhibitor JQ1 in attenuating inflammation and fibrosis in sarcopenic mice. Moreover, we preliminarily observed that JQ1 administration markedly reduces white adipose tissue mass, suggesting a potential role of BET proteins on visceral fat deposition during aging.

OBJECTIVES

Starting from those observations, the aim of this study was to investigate the ability of JQ1 to reduce adiposity in a chronic diet-induced obesity (DIO) mouse model mimicking the human metabolic syndrome.

METHODS

Male C57BL/6J mice were divided in subgroups, either fed a standard diet or a high fat diet for 22 or 12 weeks, treated over the last 14 days with JQ1 or with vehicle.

RESULTS

The results showed that JQ1 administration reduces fat mass, preserving skeletal muscle mass and function. A direct JQ1 lipolytic effect was demonstrated on mature adipocyte cultures. JQ1-mediated loss of adipose tissue mass was not associated with systemic inflammation or with lipid accumulation in muscle and liver. JQ1 administration did not impinge on skeletal muscle metabolism and oxidative capability, as shown by the lack of significant impact on mitochondrial mass and biogenesis.

CONCLUSION

In conclusion, the current data highlight a potential benefit of JQ1 administration to counteract obesity, suggesting epigenetic modulation as a prospective target in the treatment of obesity and sarcopenic obesity, despite the underlying multiorgan molecular mechanism is still not completely elucidated.

Low-Magnitude High-Frequency Vibration Attenuates Sarcopenia by Modulating Mitochondrial Quality Control via Inhibiting miR-378

BACKGROUND

Sarcopenia, the age-related decline in muscle mass and muscle strength, significantly contributes to falls, diminished quality of life, and mortality. Although mitochondrial dysfunction is increasingly implicated in sarcopenia, the underlying mechanisms are not fully discovered. Low-magnitude high-frequency vibration (LMHFV), a recommended treatment by the Centers for Disease Control and Prevention (CDC) to reduce fall risk, remains poorly understood of the mechanism on improving skeletal muscle quality. This study aims to investigate whether mitochondrial dysfunction contributes to sarcopenia and evaluate whether LMHFV mitigates sarcopenia by improving mitochondrial homeostasis.

METHODS

The relationship between mitochondria dysfunction and sarcopenia using senescence accelerated mice prone 8 (SAMP8) model was investigated, assessing muscle and mitochondria. The effects of LMHFV on muscle and mitochondria were evaluated in SAMP8 mice during sarcopenia progression. The role of miR-378 in muscle and mitochondrial homeostasis were evaluated in SAMP8 mice and transgenic over-expressing miR-378 mice (TG mice). The target gene of miR-378 was investigated by dual-luciferase reporter assay in C2C12 cells. Subsequently, we evaluated the effect of LMHFV on miR-378 using both mouse models.

RESULTS

Reduction in muscle strength was observed from the ages of month 8 to 10 in SAMP8 mice (grip strength decreased 27.1%, p = 0.0263; twitch force decreased 29.1%, p = 0.0178; tetanic force decreased 29.9%, p = 0.011), as well as muscle atrophy (cross-section area: 38.3%, p = 0.0121). Mitochondrial morphological deterioration was noticed from month 6 to 10. Mitochondrial homeostasis, including biogenesis, fusion, fission, mitophagy, and ATP production declined from month 6 to 10. Compared to control group at month 10, knocking down miR-378 in SAMP8 mice mitigated sarcopenia (twitch force increased 44.3%, p = 0.0023; tetanic force increased 51.9%, p = 0.0005), improved mitochondrial morphologies (mitochondrial number increased 1.65-fold, p = 0.0023; mitochondrial density increased 1.65-fold, p = 0.0023; mitochondrial relative area increased 9.05-fold, p = 0.0019) along with improved mitochondrial homeostasis. Over-expressing miR-378 in transgenic mice exacerbated muscle atrophy and mitochondrial deterioration significantly. The dual-luciferase reporter assay in C2C12 cells revealed that miR-378 inhibited PGC-1α directivity. LMHFV was found to mitigate sarcopenia by modulating mitochondrial homeostasis, such as attenuating mitochondrial morphological deterioration and improving mitochondrial biogenesis through increasing PGC-1α via inhibiting miR-378 in skeletal muscle.

CONCLUSIONS

Our findings indicate that mitochondrial biogenesis, fusion, fission, and mitophagy were compromised during progression of sarcopenia, with mitochondrial deterioration preceding the onset of sarcopenia symptoms. The study also demonstrated that LMHFV could attenuate sarcopenia by modulating mitochondrial quality control through inhibiting miR-378, highlighting its therapeutic potential in the management of age-related muscular degeneration.

Pauca verba on the association between protein intake and sarcopenia in older adults

Sarcopenia is a prevalent neuromuscular condition among older adults, marked by significant reductions in muscle mass and strength, which result in notable impairments in physical performance. Modifications in lifestyle habits have been frequently highlighted as essential approaches to mitigate the progression of sarcopenia, with a particular focus on protein consumption. Over the past few decades, a wealth of knowledge has emerged, driven by both observational and experimental studies exploring various factors related to protein intake, such as amount, timing, and sources. This review provides a pauca verba overview of these findings, presenting a concise yet informative summary of key insights.

Keratocan Improves Muscle Wasting in Sarcopenia by Promoting Skeletal Muscle Development and Fast-Twitch Fibre Synthesis

BACKGROUND

Osteosarcopenia refers to the co-occurrence of osteoporosis and sarcopenia, which are characterized by progressive bone density and muscle mass loss, respectively. Muscle and bone are regulated by many common genes and pathways, enabling potential co-treatment. Because keratocan protects against osteoporosis, we hypothesized it may also protect against sarcopenia, implying a new co-intervention target. This study aimed to elucidate the role and molecular mechanisms of keratocan in skeletal muscle.

METHODS

We analysed keratocan expression in the muscles of aged mice and patients with osteosarcopenia and during the differentiation of C2C12 myoblasts. The regulatory role of keratocan was assessed by knocking down or overexpressing keratocan in C2C12 cells and examining any effects on myogenic proliferation and differentiation. RNA sequencing analysis was also performed on these cells. The relationship between keratocan and enriched signalling pathways was verified using pathway inhibitors or agonists. Finally, adeno-associated virus-9 containing a muscle-specific promoter was injected into SAMP8 senile mice to observe the effects of keratocan overexpression.

RESULTS

Keratocan expression was significantly lower in the skeletal muscles of aging mice (-2.02-fold, p < 0.01) and patients with osteosarcopenia (-1.78-fold, p < 0.001) compared with that in controls. Keratocan overexpression resulted in a significant increase in the proliferation indices CCND1 (+1.43-fold, p < 0.001), Ki67 (+2.30-fold, p < 0.001) and PCNA (+1.975-fold, p < 0.01) and the differentiation indices MyoD1 (+2.156-fold, p < 0.001), MyoG (+1.52-fold, p < 0.05) and myosin heavy chain (MyHC; +2.849-fold, p < 0.01); conversely, the muscle atrophy indices MuRF-1 (-30%, p < 0.01), atrogin-1 (-87%, p < 0.01) and myostatin (-24%, p < 0.01) were significantly decreased. PI3K/AKT/mTOR was identified as a potential pathway for keratocan regulation in C2C12 cells. PI3K inhibitor LY294002 reversed the promotion of myogenesis by keratocan overexpression, while PI3K activator 740Y-P reversed the inhibitory effect of keratocan knockdown on myogenesis, promoting myofibre development and ameliorating muscle atrophy in SAMP8 aging mice. This was evidenced by increased mean muscle cross-sectional area (+38%, p < 0.0001) and muscle mass (+7%, p < 0.01) and decreased fibrosis (-40%, p < 0.01). Furthermore, keratocan facilitated the conversion of slow-to-fast muscle fibres through the PI3K/AKT/mTOR pathway, characterized by significantly increased grip strength (+42%, p < 0.01) and maximum running speed (+19%, p < 0.001), and decreased fatigue time (+13%, p < 0.05).

CONCLUSIONS

Keratocan ameliorates muscle atrophy by activating the PI3K/AKT/mTOR pathway, promoting muscle satellite cell proliferation and myogenic differentiation, and facilitating the conversion of slow-to-fast muscle fibres. Our findings demonstrate the potential of keratocan as a novel therapeutic target for osteosarcopenia.

PET/computed tomography radiomics combined with clinical features in predicting sarcopenia and prognosis of diffuse large B-cell lymphoma

BACKGROUND

The study aimed to assess the role of 18 F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) radiomics combined with clinical features using machine learning (ML) in predicting sarcopenia and prognosis of patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

A total of 178 DLBCL patients (118 and 60 applied for training and test sets, respectively) who underwent pretreatment 18 F-FDG PET/CT were retrospectively enrolled. Clinical characteristics and PET/CT radiomics features were analyzed, and feature selection was performed using univariate logistic regression and correlation analysis. Sarcopenia prediction models were built by ML algorithms and evaluated. Besides, prognostic models were also developed, and their associations with progression-free survival (PFS) and overall survival (OS) were identified.

RESULTS

Fourteen features were finally selected to build sarcopenia prediction and prognosis models, including two clinical (maximum standard uptake value of muscle and BMI), nine PET (seven gray-level and two first-order), and three CT (three gray-level) radiomics features. Among sarcopenia prediction models, combined clinical-PET/CT radiomics features models outperformed other models; especially the support vector machine algorithm achieved the highest area under curve of 0.862, with the sensitivity, specificity, and accuracy of 79.2, 83.3, and 78.3% in the test set. Furthermore, the consistency index based on the prognostic models was 0.753 and 0.807 for PFS and OS, respectively. The enrolled patients were subsequently divided into high-risk and low-risk groups with significant differences, regardless of PFS or OS ( P  < 0.05).

CONCLUSION

ML models incorporating clinical and PET/CT radiomics features could effectively predict the presence of sarcopenia and assess the prognosis in patients with DLBCL.

Why are we not exploring the potential of lower limb muscle power to identify people with sarcopenia?

Sarcopenia refers to a neuromuscular disease characterized by age-related declines in muscle mass and function. Since Professor Rosenberg first introduced the concept of sarcopenia in 1989, numerous operational paradigms have been proposed, tested, and validated against negative outcomes. The most recent recommendations advocate that dynapenia, or reduced of muscle strength, should be used alongside low muscle mass for the identification of sarcopenia. This approach is based on the understanding that impairments in muscle strength are a major consequence of muscle failure. However, empirical evidence has yielded conflicting results regarding the ability of current sarcopenia definitions to identify individuals at higher risk of adverse health-related events. Muscle power - the capacity to generate strength rapidly - has emerged as a critical domain of physical performance in old age. Not only does it decline earlier and more drastically than other measures (e.g., muscle strength), but it is also more strongly associated with adverse outcomes. In this view point, we provide an appraisal of muscle power as a more reliable indicator of muscle failure, compared with other measures (e.g., strength), for identifying individuals with sarcopenia in both geriatric and non-geriatric settings. We also discuss major challenges hindering the conduct of meaningful investigations on this subject.

Comparison of changes in skeletal muscle mass after stroke categorized by the severity of motor dysfunction: a retrospective study

[Purpose] To compare changes in skeletal muscle mass after stroke based on the severity of motor dysfunction. [Participants and Methods] This study included 17 patients who had experienced a stroke. Patients were classified into two groups based on lower limb Brunnstrom stages, i.e., those with stages III and IV (moderate motor dysfunction group; n=9), and those with stages V and VI (mild motor dysfunction group; n=8). Muscle mass was measured at the following time points: within 3 days of stroke onset; at 2 weeks ± 2 days after stroke onset; at 4 weeks ± 2 days after stroke onset; at 8 weeks ± 2 days after stroke onset, and muscle mass indices, i.e., the skeletal muscle mass index (SMI), paralyzed lower limb muscle mass, and non-paralyzed lower limb muscle mass were evaluated. Changes in these muscle mass indices between stroke onset and at 2, 4, and 8 weeks after stroke, i.e., ΔSMI, Δparalyzed lower limb muscle mass, and Δnon-paralyzed lower limb muscle mass, were calculated and the changes in each index over time were compared between the two groups. [Results] The analyses did not reveal any significant intergroup differences. [Conclusion] Even in cases of severe paralysis, appropriate nutritional and exercise therapies may help maintain the muscle mass.

Urinary odor molecules in the Otassha Study can distinguish patients with sarcopenia: A pilot study

AIM

To identify sarcopenia markers in urinary odor.

METHODS

We performed solid-phase microextraction from the headspace and gas chromatography-mass spectrometry analysis of urinary volatile organic compounds (VOCs) in 71 healthy individuals and 68 patients diagnosed with sarcopenia according to the Asian Working Group on Sarcopenia 2019 criteria. The mass-to-charge ratios (m/z) of 10 VOCs with a significant difference in the total ion chromatogram of 220 VOCs detected in this study were compared by U-test. To calculate the predictive values for sarcopenia, binomial logistic regression analyses were conducted with sarcopenia (0, 1) as the dependent variable and the m/z values of each of the 10 VOCs and all 10 VOCs as independent variables. Receiver operating characteristic (ROC) curves for predictive values were generated to evaluate diagnostic accuracy. The correlations between the predictive value and handgrip strength, usual gait speed, and skeletal muscle mass were assessed using Pearson's r.

RESULTS

We identified 10 VOCs (p-xylene, 1-butanol, d-limonene, nonanal, pyrrole, γ-butyrolactone, texanol isomer, octanoic acid, nonanoic acid, and diisobutyl phthalate) as candidate biomarkers in urine. The ROC curve analysis showed high diagnostic accuracy of the predictive values of the 10 VOCs for sarcopenia (area under the curve = 0.866, 95% confidence interval: 0.829-0.942; sensitivity, 80.9%; specificity, 81.7%). Additionally, the predictive values significantly correlated with handgrip strength (male: r = -0.505, P < 0.0001; female: r = -0.568, P < 0.0001).

CONCLUSIONS

This study identified 10 urinary VOCs as possible non-invasive biomarkers for sarcopenia, offering insights into its onset mechanism and potential therapeutic targets. Geriatr Gerontol Int 2025; 25: 307-315.

Innovative equipment for lower limb muscle strength measurement: Design and application in sarcopenia screening

BACKGROUND

Grip Strength has been established as a practical and efficient method for screening and diagnosing sarcopenia. It is recognized that with advancing age, there is a more significant decline in lower limb muscle mass compared to the upper limb. However, due to the inherent complexity of assessing lower limb muscle strength compared to measuring Grip Strength, these assessments have not been universally adopted for sarcopenia screening.

METHODS

We measured the Forefoot Strength, Heel Strength, Knee Extension Strength, and Hip Extension Strength in 98 participants using portable equipment designed for lower limb muscle strength assessment. We compared the efficacy of using lower limb muscle strength cutoff values with grip strength for the screening of sarcopenia.

FINDINGS

The optimal cutoff values for screening sarcopenia in males using Knee Extension Strength and Hip Extension Strength were 140.1 N and 121.7 N, respectively, while for females they were 91.6 N and 90.4 N, respectively. In binary logistic regression models adjusted for age and body weight, Knee Extension Strength and Hip Extension Strength were found to be associated with sarcopenia in both males and females. Moreover, the efficacy of sarcopenia screening using Knee Extension Strength or Hip Extension Strength cutoff values was superior to that of grip strength alone, and the combination of Knee Extension Strength and Hip Extension Strength cutoff values yielded the best results for sarcopenia screening.

INTERPRETATION

Measurements of Knee Extension Strength and Hip Extension Strength may potentially serve as a promising method for sarcopenia screening.

Low Muscle Mass in the Internal Medicine Ward: Prevalence and Survival Implications

BACKGROUND

Low muscle mass is common in hospitalized patients. It is associated with adverse clinical outcomes. Reported prevalence varies widely due to non-universally accepted diagnostic criteria and the heterogeneity of the populations studied. Non-surgical ill patients are underrepresented in the literature.

AIMS

To estimate the prevalence of low muscle index and its impact on survival in patients admitted to an internal medicine unit.

METHODS

We prospectively enrolled patients with abdominal CT scans on admission to the Internal Medicine ward. We assessed muscle mass index (L3MI) at the level of the L3 lumbar vertebra. The primary outcome was to estimate the prevalence of low muscle mass on admission. Secondary outcomes were to determine the relationship of low L3MI with hospital mortality, length of stay, nosocomial infections, and hospital readmission.

RESULTS

One hundred and seven patients were included. The prevalence of low L3MI was 46.7%. An L3MI of 46.3 cm2/m2 in men and 40.9 cm2/m2 in women predicted death at one year with a sensitivity of 66% and a specificity of 78% (AUC = 0.62 [95% CI 0.38-0.86]) and 69 and 66% (AUC of 0.63 [95% IC 0.47-0.78]), respectively. In-hospital mortality, death at 60, 90, and 360 d, and hospital readmission were significantly higher in patients with low L3MI.

CONCLUSION

Almost half of the patients admitted to an internal medicine ward have low muscle mass index. The cutoff point of 40.9 cm2/m2 in females and 46.3 cm2/m2 in males predicts relevant clinical variables. We established the better L3MI cutoff value to predict 12-month mortality.

Metagenomic Analysis Identifies Sex-Related Gut Microbial Functions and Bacterial Taxa Associated With Skeletal Muscle Mass

BACKGROUND

This study aimed to explore the association between gut microbiota functional profiles and skeletal muscle mass, focusing on sex-specific differences in a population under 65 years of age.

METHODS

Stool samples from participants were analysed using metagenomic shotgun sequencing. Skeletal muscle mass and skeletal muscle mass index (SMI) were quantified (SMI [%] = total appendage muscle mass [kg]/body weight [kg] × 100) using bioelectrical impedance analysis. Participants were categorized into SMI quartiles, and associations between gut microbiota, functional profiling and SMI were assessed by sex, adjusting for age, BMI and physical activity.

RESULTS

The cohort included 1027 participants (651 men, 376 women). In men, Escherichia coli (log2 fold change 3.08, q = 0.001), Ruminococcus_B gnavus (log2 fold change 2.89, q = 0.014) and Enterocloster sp001517625 (log2 fold change 2.47, q = 0.026) were more abundant in the lowest SMI compared to the highest SMI group. In contrast, Bifidobacterium bifidum (log2 fold change 3.13, q = 0.025) showed higher levels in the second lowest SMI group in women. Microbial pathways associated with amino acid synthesis (MET-SAM-PWY: log2 fold change 0.42; METSYN-PWY: log2 fold change 0.44; SER-GLYSYN-PWY: log2 fold change 0.20; PWY-5347: log2 fold change 0.41; P4-PWY: log2 fold change 0.53), N-acetylneuraminate degradation (log2 fold change 0.43), isoprene biosynthesis (log2 fold change 0.20) and purine nucleotide degradation and salvage (PWY-6353: log2 fold change 0.42; PWY-6608: log2 fold change 0.38; PWY66-409: log2 fold change 0.52; SALVADEHYPOX-PWY: log2 fold change 0.43) were enriched in the lowest SMI in men (q < 0.10). In women, the second lowest SMI group showed enrichment in energy-related pathways, including lactic acid fermentation (ANAEROFRUCAT-PWY: log2 fold change 0.19), pentose phosphate pathway (PENTOSE-P-PWY: log2 fold change 0.30) and carbohydrate degradation (PWY-5484: log2 fold change 0.31; GLYCOLYSIS: log2 fold change 0.29; PWY-6901: log2 fold change 0.27) (q < 0.05).

CONCLUSIONS

This study highlights sex-specific differences in gut microbiota and functional pathways associated with SMI. These findings suggest that gut microbiota may play a role in muscle health and point toward microbiota-targeted strategies for maintaining muscle mass.

Associations between housing quality and sarcopenia among older adults: evidence from China and India

OBJECTIVES

Housing is an important social determinant of health. However, limited studies have focused on the relationship between housing quality and sarcopenia, especially in low- and middle-income countries. This study aims to examine the association between housing quality and sarcopenia in older adults in China and India.

METHODS

The study was based on the China Health and Retirement Longitudinal Study and Longitudinal Aging Study in India. Housing quality was evaluated by five indicators, including housing materials, water sources, sanitation facilities, main fuel for cooking, and availability of electricity. Housing quality is divided into three types: good (0-1 poor housing indicators), medium (2-3 poor housing indicators), and poor (4-5 poor housing indicators). Sarcopenia was evaluated according to the Asian Working Group for Sarcopenia (AWGS) 2019 Consensus. The logistic regression model was performed to examine the association between housing quality and sarcopenia.

RESULTS

The medium (OR = 1.69, 95%CI = 1.49-1.90) and poor housing quality (OR = 2.19, 95%CI = 1.89-2.54) were associated with sarcopenia in CHARLS. Similar results were also observed in the LASI with significantly higher prevalence of sarcopenia in medium (OR = 1.22, 95%CI = 1.11-1.33), and poor housing quality (OR = 1.60, 95%CI = 1.43-1.79). Moreover, we observed a linear relationship between housing quality and the prevalence of sarcopenia both in CHARLS and LASI (all P for trend <0.001).

CONCLUSIONS

Poorer housing quality was associated with a higher prevalence of sarcopenia in older adults in China and India. Housing quality improvement plans such as access to tap water, promotion of clean energy may have a positive effect on reducing the prevalence of sarcopenia.

Nomogram to screen older adult patients attending the radiology department for sarcopenia

BACKGROUND

Sarcopenia is an age-related syndrome that can impact the physical and mental health of older adults. However, it is often overlooked in clinical practice. Therefore, we aim to construct a nomogram based on simplified discriminant parameters for screening older adult patients for sarcopenia risk.

METHODS

This cross-sectional study included 654 patients aged ≥ 60 years who underwent an examination in the radiology department between October 2023 and June 2024. Patients were diagnosed with sarcopenia according to the method and cutoff value criteria proposed the Asian Working Group on Sarcopenia (AWGS) 2019 criteria. Calf circumference (CC), SARC-F score, mid-upper arm circumference (MUAC), and SARC-CalF score were used as simplified discriminant parameters for sarcopenia. The discriminative ability of these parameters for sarcopenia was assessed using receiver operating characteristic analysis. Additionally, we included each screening parameter and evaluated it's important for screening for the presence of sarcopenia via univariate and multivariate logistic regression analysis to develop a new screening nomogram model. The performance of the nomogram was evaluated using receiver operating characteristic curves, and the performance of the nomogram model was compared to that of CC, SARC-F, MUAC, and the SARC-CalF using the Delong test.

RESULTS

Of the 654 subjects, 120 (18.3%) were diagnosed with sarcopenia, and the areas under the curve (AUCs) of the CC, SARC-F, MUAC, and SARC-CalF were 0.73, 0.61, 0.66, and 0.70, respectively. The multivariate analysis results revealed that older age, male sex, low CC, low MUAC, and low strength were related to sarcopenia. A nomogram model constructed with these five variables had an AUC of 0.84. The DeLong test showed that the diagnostic efficacy of the joint model was significantly higher than that of CC, SARC-F, MUAC, and SARC-CalF.

CONCLUSIONS

Our simple nomogram based on simplified discriminant parameters offers personalized sarcopenia screening for older adult patients attending the radiology department.

Gut dysbiosis in primary sarcopenia: potential mechanisms and implications for novel microbiome-based therapeutic strategies

Primary sarcopenia is characterized by a progressive loss of skeletal muscle mass, strength, and physical function that occurs with aging. Despite the related adverse or even serious health outcomes, no medications are currently available for treating primary sarcopenia. Here, we discuss recent advancements in understanding the mechanistic role of gut microbiota-muscle cross-talk in primary sarcopenia, and the therapeutic implications. The mechanistic insights encompass a causal role of gut dysbiosis in primary sarcopenia, potentially mediated through gut microbiota-derived bioactive metabolites, such as short-chain fatty acids (SCFAs), secondary bile acids, and their associated signaling pathways, which may be translated into the development of new microbiome-based treatment and diagnostic approaches. Furthermore, we identify challenges that need addressing in future studies to facilitate the translation into potential novel treatment and differential diagnosis for older individuals with sarcopenia.

The Dietary Inflammatory Index and Sarcopenia in Older Adults in Four Chinese Provinces: A Cross-Sectional Study

Background: Sarcopenia associated with aging severely affects the quality of life of the elderly; diets have been shown to elicit an inflammatory response in the body, and diets that promote inflammation may lead to damage to muscles. The Dietary Inflammatory Index (DII) has been developed to quantify the inflammatory potential of individual diets. Therefore, this study aimed to investigate the association between the DII, sarcopenia and its components in elderly Chinese people. Methods: In this study, data were obtained from the China Nutrition Improvement Strategies and Applications for the Elderly Research Programme. An assessment of sarcopenia was carried out according to the Asian Working Group on Sarcopenia's (AWGS2019) criteria. The DII was calculated using food intake data obtained using the FFQ method, and then the quartile method was used to categorize the subjects into four groups. Multifactor logistic regression was conducted to examine the associations between DII, sarcopenia and its components. Results: This study included 993 subjects over the age of 65, and the prevalence of sarcopenia was 20.2%. The mean DII score of the study population was 0.99 ± 0.1. After adjusting for the confounders age, gender, marital status, and educational level, the risk of sarcopenia was 1.66 times higher in group Q4 than in group Q1 (p-trend < 0.05). However, this relationship is not statistically significant when other more confounding factors are added. Nevertheless, when further analyzing the relationship between DII and sarcopenia components, it was found that after adjusting the model, a higher DII was associated with a risk of muscle strength loss (OR = 1.65, p-trend < 0.05). Conclusions: Higher DII scores increase the risk of muscle strength loss in older adults. By guiding older adults to adopt a more anti-inflammatory diet, muscle health can be improved in terms of increased muscle strength. Further cohort or interventional studies are necessary to validate our findings.

Age, cancer, and the dual burden of cancer and doxorubicin in skeletal muscle wasting in female rats: which one to blame?

Sarcopenia and cancer cachexia are two life-threatening conditions often misdiagnosed. The skeletal muscle is one of the organs most adversely affected by these conditions, culminating in poor quality of life and premature mortality. In addition, it has been suggested that chemotherapeutic agents exacerbate cancer cachexia, as is the case of doxorubicin. Herein, we sought to investigate markers of inflammation and neuromuscular junction (NMJ) remodeling during aging and in response to cancer or cancer with chemotherapy. To address this, we utilized female rats across three age groups - young, adult, and old - to examine age-related changes, with old rats serving as a sarcopenia model. Additionally, a chemically-induced breast cancer (BCa) model was implemented in female adult rats, both without (adult BCa) or with doxorubicin administration (adult BCaDOX), to study cancer cachexia. The atrophy of the gastrocnemius muscle was observed in old, adult BCa and adult BCaDOX rats compared to adult ones. No signs of inflammation or NMJ impairment were observed in adult BCa or adult BCaDOX rats, except for the low levels of the subunit α1 of the acetylcholine receptor in adult BCaDOX rats compared to adult ones. In contrast, old rats presented high serum levels of interleukin 6, brain-derived neurotrophic factor (BDNF) and calcitonin gene-related peptide compared to young rats. In the gastrocnemius muscle, BDNF levels were decreased in old rats compared to adult rats, suggesting impaired skeletal muscle regeneration upon age-induced damage. The BDNF muscle levels were inversely correlated with its levels in circulation in adult and old rats. Hence, this work highlights BDNF as a specific biomarker of age-induced skeletal muscle atrophy, at least, in the differential diagnosis against cancer- or cancer with chemotherapy-induced muscle wasting.

A 4-Week Mobile App-Based Telerehabilitation Program vs Conventional In-Person Rehabilitation in Older Adults With Sarcopenia: Randomized Controlled Trial

BACKGROUND

Sarcopenia is closely associated with a poor quality of life and mortality, and its prevention and treatment represent a critical area of research. Resistance training is an effective treatment for older adults with sarcopenia. However, they often face challenges when receiving traditional rehabilitation treatments at hospitals.

OBJECTIVE

We aimed to compare the effects of a digital rehabilitation program with those of traditional therapist-supervised rehabilitation training on older adults with sarcopenia.

METHODS

In total, 58 older adults with sarcopenia were recruited offline and randomized (1:1) into 2 groups: the telerehabilitation group (TRG, n=29, 50%) and the in-person rehabilitation group (IRG, n=29, 50%). Both groups underwent 4-week resistance training targeting 6 major muscle groups. The TRG received exercise guidance via a mobile app, while the IRG received in-person training from a therapist. Offline assessments of body composition, grip strength, and balance using the 30-Second Arm Curl Test (30SACT), 30-Second Sitting-to-Rising Test (30SSRT), quadriceps femoris extension peak torque (EPT) and extension total power (ETP), Berg Balance Scale (BBS), Timed Up-and-Go Test (TUGT), 6-Minute Walk Test (6MWT), and Instrumental Activities of Daily Living (IADL) scale, were conducted before and after the intervention.

RESULTS

Of the 58 patients, 51 (88%; TRG: n=24, 47%; IRG: n=27, 53%) completed the trial. After 4 weeks of intervention, the mean grip strength increased from 18.10 (SD 5.56) to 19.92 (SD 5.90) kg in the TRG (P=.02) and from 18.59 (SD 5.95) to 19.59 (SD 6.11) kg in the IRG (P=.01). The 30SACT and 30SSRT scores increased from 12.48 (SD 2.68) to 14.94 (SD 3.68) times (P=.01) and from 15.16 (SD 7.23) to 16.58 (SD 8.42) times (P=.045), respectively, in the TRG and from 12.25 (SD 4.19) to 14.68 (SD 4.36) times (P=.003) and from 14.31 (SD 4.04) to 16.25 (SD 4.91) times (P=.01), respectively, in the IRG. The quadriceps femoris EPT increased from 26.19 (SD 10.26) to 35.00 (SD 13.74) Nm (P=.004) in the TRG and from 26.95 (SD 11.81) to 32.74 (SD 12.33) Nm (P=.003) in the IRG. The BBS scores significantly improved in both groups (P<.001), with the mean TRG score increasing by 3.19 (SD 2.86) points and the mean IRG score by 3.06 (SD 2.44) points. Neither group exhibited significant within-group changes on the TUGT or the 6MWT. Both groups reported significant improvements in the IADL (TRG: P=.04; IRG: P=.02). Between-group comparisons revealed no significant differences in changes in all indicators.

CONCLUSIONS

A 4-week remote resistance training program is effective in improving strength, balance, and the IADL in older adults with sarcopenia, with effects comparable to rehabilitation supervised by a physical therapist. Telerehabilitation may be a convenient and effective alternative for older adults with sarcopenia who have limited access to rehabilitation resources.

TRIAL REGISTRATION

ChiCTR 2300071648; https://www.chictr.org.cn/showprojEN.html?proj=196313.

Are Dietary Patterns Relevant for Reducing the Risk of Fractures and Sarcopenia?

PURPOSE OF REVIEW

This review aims to summarise recent evidence on the effects of dietary patterns on the risk of bone fractures and sarcopenia.

RECENT FINDINGS

Several dietary patterns have been investigated in relation to musculoskeletal health, including Mediterranean Dietary Patterns (MDP), Dietary Inflammatory Indices, vegetarian and vegan diets. Adherence to 'healthier' dietary patterns appears to be protective against fractures and sarcopenia, with the strongest protective associations found between the MDP and fractures. Individuals following vegan or vegetarian eating patterns need to be aware of calcium and vitamin D requirements to maintain musculoskeletal health. Although more healthy dietary patterns may be protective for musculoskeletal health the current evidence base is limited by variation in the construction of dietary pattern scores and reported outcome measures. Future research should fully report scoring methods, intakes of dietary components across scoring groups or categories, and consider outcome measures that allow for better comparison between studies.

Gut microbiota in patients with sarcopenia: a systematic review and meta-analysis

Background

Intestinal dysbiosis was considered a pivotal pathological mechanism underlying sarcopenia. Despite the fervor surrounding research in this domain, substantial controversy persists regarding the obtained outcomes.

Objective

To systematically summarized the disparities in gut microbiota composition between the group afflicted by sarcopenia and non-sarcopenia controls.

Methods

PubMed, Medline, CINAHL, EMBASE, Scopus, Web of Science and Google Scholer, Cochrane Library and gray literature sources were systematically searched for in randomized controlled trials. Meta-analysis and random-effects meta-regression were conducted using Rev. Man 5.3. Overall effect was measured using Hedges's g and determined using Z-statistics. Cochran's Q test and I 2 were used to investigate heterogeneity. The Newcastle-Ottawa Scale was used to assess overall quality of evidence.

Results

Ten studies, including 421 cases of sarcopenia and 1,642 cases of controls, were included in the meta-analysis. Patients with sarcopenia showed significantly reduced gut microbiota in α diversity, and β diversity was significantly different in 8/9 of included studies. We also found more abundance of phylum Proteobacteria and genus Escherichia-Shigella, and less abundance of phylum Firmicutes and genus Faecalibacterium, Prevotella 9, Blautia in the sarcopenia group.

Conclusion

The gut microbiota composition in patients with sarcopenia has undergone alterations, serving as a fundamental reference for further investigation into the potential pathogenic mechanisms and treatment strategies for sarcopenia.

Serum ALT activity and its isoenzymes as potential biomarkers for diagnosis of Sarcopenia in older adults: a retrospective, cross-sectional study

BACKGROUND

Alanine aminotransferase (ALT) is an enzyme crucial for energy and protein metabolism in muscle cells. Despite this, its association with sarcopenia remains inadequately explored. This study aims to investigate the correlation between serum levels of ALT-related indicators (ALT activity, ALT1, ALT2, and ALT1/ALT2 ratio) and sarcopenia measures, as well as to develop a diagnostic model for sarcopenia in older individuals.

METHODS

This retrospective study assessed 653 older adults (aged ≥ 55 years), 109 of whom were studied for the association of ALT1, ALT2, and ALT1/ALT2 ratio with sarcopenia measures. Muscle mass was measured by dual energy X-ray absorptiometry. Hand grip strength (HGS) was measured with a digital dynamometer, and physical performance was assessed through the 6-meter gait speed and the five-times sit-to-stand test (FTSST). Binary logistic regression analysis was used to evaluate associations between ALT-related indicators (ALT activity and ALT1/ALT2 ratio) and sarcopenia. The diagnostic model was developed using binary logistic regression with backward selection, and the diagnostic performance of the model was evaluated by the receiver operator characteristic curve (ROC) curve.

RESULTS

Older adults with sarcopenia exhibited a lower serum ALT activity and a higher ALT1/ALT2 ratio compared to those without sarcopenia. ALT activity tertiles, but not ALT1 or ALT2 tertiles alone, correlated with HGS, gait speed, FTSST, and appendicular skeletal muscle mass index (ASMI), serving as independent protective factors for low HGS, low physical performance, low ASMI, and sarcopenia. Tertiles of the ALT1/ALT2 ratio were significantly associated with HGS and FTSST, and were proved independent risk factors for low physical performance and sarcopenia by binary logistic regression analysis. An optimal Model A (based on ALT activity) was established for sarcopenia to develop a new Logit_P1 (p < 0.001). Similarly, an optimal Model B (based on ALT1/ALT2 ratio tertiles) was established for sarcopenia to develop a new Logit_P2 (p < 0.001). According to the ROC curve analysis for discriminating sarcopenia, the performance of Logit_P2 (area under the curve = 0.830) seemed better than that of Logit_P1 (area under the curve = 0.789), although the difference was not statistically significant (p = 0.214).

CONCLUSIONS

In older adults, a low serum ALT activity level was an independent risk factor for low ASMI, HGS, physical performance, and sarcopenia. The serum ALT1/ALT2 ratio emerged as an independent risk factor for low physical performance and sarcopenia. The new indices, Logit_P1 and Logit_P2, demonstrated diagnostic value for sarcopenia.

Poor muscle quality: A hidden and detrimental health condition in obesity

Poor muscle quality (MQ) is a hidden health condition in obesity, commonly disregarded and underdiagnosed, associated with poor health-related outcomes. This narrative review provides an in-depth exploration of MQ in obesity, including definitions, available assessment methods and challenges, pathophysiology, association with health outcomes, and potential interventions. MQ is a broad term that can include imaging, histological, functional, or metabolic assessments, evaluating beyond muscle quantity. MQ assessment is highly heterogeneous and requires further standardization. Common definitions of MQ include 1) muscle-specific strength (or functional MQ), the ratio between muscle strength and muscle quantity, and 2) muscle composition (or morphological MQ), mainly evaluating muscle fat infiltration. An individual with obesity might still have normal or higher muscle quantity despite having poor MQ, and techniques for direct measurements are needed. However, the use of body composition and physical function assessments is still limited in clinical practice. Thus, more accessible techniques for assessing strength, muscle mass, and composition should be further explored. Obesity leads to adipocyte dysfunction, generating a low-grade chronic inflammatory state, which leads to mitochondrial dysfunction. Adipocyte and mitochondrial dysfunction result in metabolic dysfunction manifesting clinically as insulin resistance, dyslipidemia, and fat infiltration into organs such as muscle, which in excess is termed myosteatosis. Myosteatosis decreases muscle cell function and insulin sensitivity, creating a vicious cycle of inflammation and metabolic derangements. Myosteatosis increases the risk of poor muscle function, systemic metabolic complications, and mortality, presenting prognostic potential. Interventions shown to improve MQ include nutrition, physical activity/exercise, pharmacology, and metabolic and bariatric surgery.

Gait speed assessment in confined spaces: Development of a novel automated 4-m static-start test to measure dynamic-start gait speed

OBJECTIVES

To promote standardization and feasible measurements of gait speed across the field, we developed a device that used light detection and ranging (LiDAR) technology to measure gait speed from a standing-start testing procedure conducted on a 4-m total walkway. We compared this automated (LiDAR-based) standing-start 4-m gait speed test (AS-4MG) with automated and manual (stopwatch-based) dynamic-start 4-m gait speed tests (AD-4MG and MD-4MG, respectively) on between-method agreement, measurement repeatability, and predictive validity with functional outcomes.

METHODS

A sample of 48 community-dwelling adults (mean [SD], 69 [9] years) participated in this method comparison study. Participants completed a survey and a physical function assessment, from which self-reported stair difficulty, handgrip strength, sit-to-stand performance, and gait speed (AS-, AD-, and MD-4MG) were measured.

RESULTS

Mean AS-4MG, AD-4MG, and MD-4MG were 1.12, 1.13, and 1.14 m/s, respectively, with a strong correlation (r = 0.94) and no systematic bias observed between AS-4MG and the referent AD-4MG. In the analyses of repeated gait measurements, coefficients of repeatability were <0.20 m/s for the automated tests (0.16 and 0.18 m/s for AS-4MG and AD-4MG, respectively) but not for MD-4MG (0.22 m/s). Correlations between gait speed and functional measures ranged between 0.44 and 0.68 (Ps < 0.01). Correlations for the automated tests were comparable, while AS-4MG correlations tended to exceed MD-4MG correlations.

CONCLUSIONS

In community-dwelling adults, the AS-4MG test was unbiased when compared with the AD-4MG, encompassing a 9-m walkway, with both tests showing equivalence of measurement repeatability and predictive validity. The AS-4MG potentially allows gait measurements in confined spaces (e.g., doctor's office) where the gait speed test was previously unfeasible. Geriatr Gerontol Int 2025; ••: ••-••.

Differential effects of EPA and DHA on aging-related sarcopenia in mice and possible mechanisms involved

Sarcopenia frequently occurs with aging and leads to major adverse impacts in elderly individuals. The protective effects of omega-3 polyunsaturated fatty acids against aging-related sarcopenia have been demonstrated; however, the effect and underlying mechanism of EPA or DHA alone remain inconclusive. Hence, the present study was aimed to clarify the differential effects and possible mechanisms of EPA and DHA on aging-related sarcopenia. In this study, two-month-old and eighteen-month-old male C57BL/6J mice were fed with an AIN-93M diet and an AIN-93M diet containing 1% EPA or 1% DHA for 24 weeks, respectively. The results revealed that EPA and DHA supplementation effectively alleviated the decline in grip strength, skeletal muscle mass, and myofiber cross-sectional areas in aged mice, with EPA exhibiting a better effect against aging-related sarcopenia than DHA. The ROS scavenging role of EPA in aged skeletal muscle was also superior to that of DHA. Additionally, EPA showed a stronger role in improving protein turnover and myogenesis in aged skeletal muscle, as evidenced by suppressing the activation of FoxO3a and NF-κB, blunting the expression levels of muscle atrophy markers MAFbx and MuRF1, activating the PI3K/Akt/mTOR signaling pathway, and elevating MyoD expression. Moreover, EPA also revealed a better effect on inhibiting mitochondria- and endoplasmic reticulum stress-mediated apoptosis in aged skeletal muscle. Furthermore, EPA manifested a more pronounced effect on improving mitochondrial damage of aged skeletal muscle than DHA, and the reason might be due to its superior capability of regulating mitochondrial quality control, as clearly shown by enhancing mitochondrial biogenesis through the AMPK/PGC-1α-dependent pathway, restraining the loss of mitochondrial fusion and fission proteins including Opa1, Mfn2, and Fis1, and promoting mitophagy via the PINK1/Parkin-dependent pathway.

From Clinical to Benchside: Lacticaseibacillus and Faecalibacterium Are Positively Associated With Muscle Health and Alleviate Age-Related Muscle Disorder

Sarcopenia is an age-related muscle disorder that increases risks of adverse clinical outcomes, but its treatments are still limited. Gut microbiota is potentially associated with sarcopenia, and its role is still unclear. To investigate the role of gut microbiota in sarcopenia, we first compared gut microbiota and metabolites composition in old participants with or without sarcopenia. Fecal microbiota transplantation (FMT) from human donors to antibiotic-treated recipient mice was then performed. Specific probiotics and their mechanisms to treat aged mice were identified. Old people with sarcopenia had different microbial composition and metabolites, including Paraprevotella, Lachnospira, short-chain fatty acids, and purine. After FMT, mice receiving microbes from people with sarcopenia displayed lower muscle mass and strength compared with those receiving microbes from non-sarcopenic donors. Lacticaseibacillus rhamnosus (LR) and Faecalibacterium prausnitzii (FP) were positively related to muscle health of old people, and enhanced muscle mass and function of aged mice. Transcriptomics showed that genes related to tricarboxylic acid cycle (TCA) were enriched after treatments. Metabolic analysis showed increased substrates of TCA cycle in both LR and FP supernatants. Muscle mitochondria density, ATP content, NAD+/NADH, mitochondrial dynamics and biogenesis proteins, as well as colon tight junction proteins of aged mice were improved by both probiotics. LR and the combination of two probiotics also benefit intestinal immune health by reducing CD8+ IFNγ+ T cells. Gut microbiota dysbiosis is a pathogenesis of sarcopenia, and muscle-related probiotics could alleviate age-related muscle disorders mainly through mitochondria improvement. Further clinical translation is warranted.

Impact of Resistance Exercise and Nitrate Supplementation on Muscle Function and Clinical Outcomes After Knee Osteoarthritis Surgery in Middle-Aged Women with Sarcopenia: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Background/Objectives: Sarcopenia, characterized by reduced muscle mass and strength, is associated with osteoarthritis (OA), particularly in middle-aged women, and may worsen postoperatively. Resistance exercise (RE) can resolve sarcopenia; however, recovery is often suboptimal. Nitrate (NO3-) supplementation may enhance muscle recovery and complement RE. We investigated whether NO3- supplementation combined with RE improves thigh muscle mass and strength in middle-aged women during postoperative rehabilitation. Methods: We conducted a prospective randomized placebo-controlled double-blind study including 36 middle-aged women with sarcopenia and cartilage defects undergoing mesenchymal stem cell implantation. Participants were assigned to RE with NO3- supplementation (NG, n = 18) or with placebo (PG, n = 18) groups. Both groups underwent 12 weeks of supervised RE. The primary outcomes were thigh muscle cross-sectional area (CSA) and knee strength, whereas functional and clinical measures, including the Short Physical Performance Battery (SPPB), skeletal muscle index (SMI), International Knee Documentation Committee (IKDC), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, were secondary outcomes. Results: Thigh muscle CSA decreased in the PG but was maintained in the NG. Knee extension strength improved significantly in the NG compared with that in the PG at 6 and 12 weeks. Knee flexion strength also improved rapidly in the NG, with a significant increase at 6 weeks. SPPB and IKDC scores improved significantly in the NG. However, similar improvements were observed for WOMAC scores in both groups. Conclusions: NO3- supplementation combined with RE effectively prevented muscle atrophy and enhanced muscle strength in our study participants, indicating potential for improving postoperative recovery.