Sarcopenia and nervous system disorders

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.

Association of nutritional and inflammatory status with all-cause and cardiovascular mortality in adults with sarcopenia: Insights from NHANES

OBJECTIVE

Associations between scores on the advanced lung cancer inflammation index (ALI) and mortality among sarcopenic adults remains unknown. This study investigates the relationship between ALI and both all-cause and cardiovascular mortality among adults with sarcopenia.

METHODS

The study involved sarcopenic adults from the National Health and Nutrition Examination Survey (NHANES), conducted between 1999 and 2006 and 2011-2018. Mortality information was acquired from the National Death Index, which tracks deaths through to December 31, 2019. Weighted multivariable Cox proportional hazards regression was employed to calculate hazard ratios (HRs) for mortality in different models. Additionally, the restricted cubic spline (RCS) method was used to investigate non-linear associations. Subgroup analyses and sensitivity analyses were conducted to detect differences and examine the reliability of the findings.

RESULTS

This study included 2074 American adults with sarcopenia categorized into quartiles. 701 deaths occurred from all causes, with 236 linked to cardiovascular issues. Multivariate Cox regression models showed that those in the highest ALI quartile had a lower all-cause mortality rate than those in the lowest quartile (model 1: HR = 0.69, 95 % CI 0.55-0.87, P = 0.002; model 2: HR = 0.73, 95 % CI 0.56-0.94, P = 0.017). Likewise, those in the highest ALI quartile had a lower risk of death from cardiovascular causes (model 1: HR = 0.55, 95 % CI 0.36-0.85, P = 0.007; model 2: HR = 0.59, 95 % CI 0.37-0.95, P = 0.031). RCS results revealed an L-shaped correlation between ALI score and all-cause mortality.

CONCLUSIONS

A higher ALI score was strongly associated with lower rates of both all-cause and cardiovascular mortality among sarcopenic adults, particularly in the older population, males, smokers, and those with hypertension. This suggests that ALI may serve as a risk stratification tool.

Sarcopenia in Parkinson's disease: from pathogenesis to interventions

Parkinson's disease (PD) and sarcopenia are prevalent age-related conditions that often coexist in affected individuals. Sarcopenia is particularly common among PD patients, with severe cases affecting approximately one in five individuals with the disease. Furthermore, sarcopenia is closely linked to the accelerated progression of PD, diminished quality of life, greater susceptibility to falls and fractures, and increased mortality risk. Although the precise mechanisms remain unclear, numerous studies suggest that factors such as the accumulation of α-Synuclein in skeletal muscle, loss of motor neurons, inflammation, phosphate toxicity, hormonal dysregulation, vitamin D deficiency, intestinal flora imbalances, and dysfunction of the gut-muscle-brain axis contribute to sarcopenia in PD. Understanding these mechanisms provides valuable insights into the relationship between PD and sarcopenia and establishes a foundation for future research and therapeutic strategies. This review examines the mechanisms underlying sarcopenia in PD, methods for its screening and assessment, and potential avenues for future research, including strategies for risk reduction and treatment.

Genetic Association Between Attention-Deficit/Hyperactivity Disorder and Sarcopenia: A Bidirectional Two-Sample, Two-Step Mendelian Randomized Study

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders in children and adolescents, often accompanied by motor function disorders. Sarcopenia not only has skeletal muscle dysfunction but also has neurocognitive dysfunction. At present, there is no research to explore the relationship between ADHD and skeletal muscle function. The purpose of this study is to explore whether there is a causal effect between ADHD and sarcopenia.

METHODS

In this study, genome-wide association study data of ADHD, appendicular lean mass (ALM), hand grip strength, and walking pace (WP) were extracted from public databases. The bidirectional two-sample Mendelian randomization (MR) method was employed to investigate the correlation between ADHD and sarcopenia-related indicators, and the inverse-variance weighted analysis as the primary analysis method.

RESULTS

Based on the forward MR analysis, a potential causal relationship exists between ADHD and ALM (odds ratio [OR]=1.020, 95% confidence interval [CI]: 1.012-1.029, p<0.001). The reverse MR analysis indicates a link between WP and the risk of ADHD (OR=2.712, 95% CI: 1.609-4.571, p<0.001), with an accelerated WP increasing the likelihood of ADHD. Nevertheless, other MR analysis results did not show significant differences.

CONCLUSION

The findings of this study indicate an intricate causal relationship between ADHD and sarcopenia, suggesting the absence of a clear link. WP may be used as one of the indicators to evaluate the risk of ADHD. At the same time, we should pay more attention to the ALM of ADHD patients.

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 impact of chronic diseases and lifestyle on sarcopenia risk in older adults: a population-based longitudinal study

Background

Sarcopenia, characterized by the gradual decline of muscle mass and strength, seriously affects the health and mobility of older adults. The purpose of this study is to investigate the risk factors for sarcopenia, particularly the relationship between chronic diseases and lifestyle factors in individuals aged 60 and over.

Methods

This study used data from the Longitudinal Study on Health and Retirement in China (CHARLS) collected in 2011 and 2015. All eligible participants were classified according to the standards established by the Asian Sarcopenia Working Group in 2019. The evaluation of sarcopenia was based on a comprehensive score across five dimensions: strength, assistance in walking, rise from a chair, climb stairs, and falls. A multivariate logistic regression model was employed to explore the risk factors for sarcopenia.

Results

The risk of sarcopenia is significantly influenced by multiple factors. Key findings include the association between past drinking and an increased risk of sarcopenia (HR = 2.198, 95% CI: 1.072-4.560, p < 0.05), indicating that individuals with a history of drinking have more than twice the risk of sarcopenia compared to non-drinkers. Chronic diseases such as stroke were also associated with a significantly elevated risk (HR = 3.137, 95% CI: 1.128-8.721, p < 0.05). Conversely, participation in social activities significantly reduced the risk of sarcopenia (HR = 0.482, 95% CI: 0.265-0.876, p < 0.05). A three-piece spline regression model revealed a nonlinear relationship between physical activity and the risk of sarcopenia, characterized by an initial decline in risk followed by an increase as physical activity levels rose. Moderate-intensity physical activity reduced the risk of sarcopenia by approximately 35% (HR ≈ 0.65). However, high-intensity physical activity led to a rebound in risk, increasing the likelihood of sarcopenia relative to moderate activity. Similarly, adequate sleep duration was associated with a reduced risk of sarcopenia, whereas excessive sleep counteracted this benefit.

Conclusion

The findings underscore the critical role of lifestyle modifications and balanced physical activity in mitigating the risk of sarcopenia among older adults. Implementing targeted interventions for high-risk groups is essential to reduce the incidence of sarcopenia.

Prevalence of and risk factors for sarcopenia in patients with epilepsy

BACKGROUND

Epilepsy is a chronic neurological disorder with a burden of comorbidities. Knowledge regarding sarcopenia prevalence and associated risk factors in patients with epilepsy remains limited, which prompted us to conduct the present study.

METHODS

This cross-sectional study enrolled patients with epilepsy from our epilepsy clinic and controls from the staff at National Cheng Kung University Hospital, Tainan, Taiwan. Sarcopenia was defined using the criteria outlined by the 2019 Asian Working Group for Sarcopenia and the 2010 European Working Group on Sarcopenia in Older People. Muscle mass (skeletal muscle mass index) was measured through bioelectrical impedance, muscle strength was assessed using hand grip tests, and physical performance was evaluated using the 6-m walk test. Hormone (testosterone, growth hormone, and insulin-like growth factor-1) and vitamin D levels were measured. Descriptive statistics and logistic regression models were used to estimate the prevalence of sarcopenia and identify sarcopenia risk factors in patients with epilepsy.

RESULTS

This study enrolled 300 adults (mean age: 42.9 ± 14.7 years; women: 53.7 %). The epilepsy and control groups comprised 200 and 100 participants, respectively. The overall prevalence of sarcopenia was 31.3 % and it was significantly higher (p = 0.004) in women (20.7 %) than in men (10.6 %). The prevalence was higher in the epilepsy group than in the control group (36.0 % vs. 22.0 %, p = 0.014). Logistic regression revealed female, age (≥ 65 year) and low body mass index (BMI) were influenced the risk of sarcopenia in all participants. Importantly, epilepsy is significantly associated sarcopenia. The BMI, protein level, calf circumference, and use of enzyme-inducing antiseizure medications (EIASM) influenced the risk of sarcopenia in the epilepsy group.

CONCLUSION

The prevalence of sarcopenia is significantly higher in patients with epilepsy than in the control participants. Low BMI, protein level, calf circumference, and the use of EIASM may increase the risk of sarcopenia in this population. Our findings underscore the need for mitigating sarcopenia risk in patients with epilepsy.

Exploring the mediating roles of depression and cognitive function in the association between sarcopenia and frailty: A Cox survival analysis approach

BACKGROUND

Despite earlier research indicating a potential link between the development of sarcopenia and an elevated risk of frailty, the lack of comprehensive prospective data on the correlation between sarcopenia and frailty incidence leaves open the question of whether depression and cognitive function mediate this association.

OBJECTIVE

The principal aim of the current investigation was to evaluate the intricate interplay among sarcopenia, depression, and cognitive function collectively influence the risk of developing frailty.

METHODS

The participants included in this study were obtained from three waves of the China Health and Retirement Longitudinal Study (CHARLS), which collectively encompassed a total of 3,108 participants. To examine the interrelationships among sarcopenia, depression, cognitive function, and the incidence of frailty, we employed Cox regression models along with structural equation modelling, while making necessary adjustments for baseline demographic characteristics and various lifestyle factors.

RESULTS

During a 4-year follow-up, we documented 753 frailty events. Compared to those with nonsarcopenia, those with possible sarcopenia and sarcopenia presented risk ratios for frailty events of 1.354 (95 % CI: 1.156, 1.586) and 1.514 (95 % CI: 1.203, 1.907), respectively. Stratified analyses by different statuses of sarcopenia further revealed that the significant effect of depression on frailty was present across all groups (nonsarcopenia, possible sarcopenia and sarcopenia), whereas the effect of cognitive function on frailty was limited to the non-sarcopenia and possible sarcopenia groups. Mediation analysis showed that sarcopenia was correlated not only with frailty through depression and cognitive function separately but also through a chain-mediated effect of depression and cognitive function together.

CONCLUSIONS

Sarcopenia is associated with frailty, depression and cognitive function playing partial, mediating roles. Frailty's susceptibility to depression and cognitive function differs based on sarcopenia status. Therefore, comprehensive interventions that include sarcopenia screening, interventions, improvements in depression, the promotion of mental health, and delays in cognitive decline will be more effective in preventing and delaying frailty. This effectiveness is particularly relevant for middle-aged and older adults who reside in China.

Indoor air pollution by solid fuel usages for cooking is longitudinally associated with possible sarcopenia in middle-aged Chinese population

Objectives

The Asia Working Group of Sarcopenia (AWGS) 2019 consensus proposed a new concept named "possible sarcopenia". The present study was to estimate the association between indoor air pollution by solid fuel usages for cooking and possible sarcopenia among middle-aged and older Chinese population.

Methods

A longitudinal cohort analysis was carried out using nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS). A total of 17,708 participants were recruited and followed up in the CHARLS. Cox proportional hazards models were used to estimate the effects of cooking fuel usages on the new onset of possible sarcopenia. Stratified analyses were performed according to gender and age, and sensitivity analyses were performed using the complete dataset.

Results

A total of 4,653 participants were included in the final cohort analysis. During the follow-up of 4 years (2011-2015), a total of 1,532 (32.92%) participants developed new-onset possible sarcopenia. Compared with clean fuel usages for cooking, solid fuel usages were associated with a higher risk of possible sarcopenia (HR = 1.37, 95% CI = 1.23-1.52, p-value < 0.001). After adjusting for potential confounders, there was a trend for association between solid fuel usages and an increased risk of possible sarcopenia. Stratified analyses by gender and age demonstrated a stronger association of the solid fuel usages with possible sarcopenia in the middle-aged female participants (Model 1: HR = 1.83, 95% CI = 1.24-2.69, p-value = 0.002; Model 2: HR = 1.65, 95% CI = 1.10-2.47, p-value = 0.016). Sensitivity analyses indicated that the results were robust.

Conclusion

Indoor air pollution from solid fuel usages for cooking was a modifiable risk factor for sarcopenia, especially in middle-aged female population. These findings provide a new prevention strategy to reduce the growing burden of sarcopenia, especially for middle-aged female individuals using solid fuels for cooking.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Lower creatinine-to-cystatin c ratio associated with increased risk of incident amyotrophic lateral sclerosis in the prospective UK biobank cohort

Reduced muscle mass has been associated with the progression and prognosis of amyotrophic lateral sclerosis (ALS). However, it remains unclear whether decreased muscle mass is a risk factor for ALS or a consequence of motor neuron degeneration. Recently, serum creatinine-to-cystatin C ratio (CCR) have emerged as promising biomarkers for assessing muscle mass. We aimed to explore the association between CCR and the incidence of ALS using data from the UK Biobank. Between 2006 and 2010, 446,945 participants were included in the baseline. CCR was calculated as the ratio of serum creatinine to cystatin C. Cox regression models were used to analyze the relationship between CCR and ALS incidence. Furthermore, subgroup analyses were conducted to investigate potential covariates in these relationships. After adjusting for all covariates, the multivariate Cox regression analysis revealed a significant association between decreased CCR and an increased risk of ALS (hazard ratio (HR) = 0.990, 95% confidence interval (CI): 0.982-0.999, P = 0.026). Participants were stratified into groups based on CCR tertiles. Compared with participants in the highest tertiles of CCR, those in the lowest (HR = 1.388, 95% CI: 1.032-1.866, P = 0.030) and medium tertiles (HR = 1.348, 95% CI: 1.045-1.739, P = 0.021) had an increased risk of ALS incidence. Subgroup analysis showed that the relationship between CCR and ALS incidence was particularly significant among participants aged < 65 years (CCR tertile 1: HR = 1.916, 95% CI: 1.366-2.688, P < 0.001; CCR tertile 2: HR = 1.699, 95% CI: 1.267-2.278, P < 0.001). The present results demonstrate that lower CCR is significantly associated with a higher risk of ALS.

Effect of Sarcopenia on Functional Recovery in Acute Stroke Patients Admitted for Standard Rehabilitation Program

Background and Objectives: Sarcopenia is a significant concern in stroke rehabilitation, with a high prevalence reported in acute stroke patients. This study examines the effect of sarcopenia on rehabilitation outcomes in acute stroke patients. Materials and Methods: This study was conducted with acute stroke patients admitted within 90 days of onset to the rehabilitation hospital. Participants were divided into a stroke with sarcopenia group and a stroke without sarcopenia group. Evaluations were conducted at baseline, 4 weeks, and 8 weeks, including the following assessments: manual muscle testing (MMT), Berg Balance Scale (BBS), functional ambulation category (FAC), and Modified Barthel Index (MBI). Both groups received an identical rehabilitation program for 8 weeks. Results: Significant within-group improvements were observed in both groups across all measures (p < 0.05). However, the stroke with sarcopenia group showed significantly less improvement in MMT, BBS, FAC, and MBI compared to the stroke without sarcopenia group at both 4 and 8 weeks (p < 0.05). Conclusions: These results underscore the significant impact of sarcopenia on functional recovery in stroke patients, despite both groups receiving identical rehabilitation programs. The presence of sarcopenia was a critical predictor of poorer outcomes in muscle strength, balance, ambulation, and activities of daily living. Given these findings, specific rehabilitation strategies targeting sarcopenia are needed to improve recovery in stroke patients. Future research should include larger sample sizes, longer follow-ups, and sarcopenic patient-specific rehabilitation programs.

Insulin resistance and sarcopenia: a prognostic longitudinal link to stroke risk in middle-aged and elderly Chinese population

BACKGROUND

Stroke is the leading cause of death in middle-aged and elderly people in China. Insulin resistance (IR) and sarcopenia are both closely associated with metabolic diseases. However, the relationship between these two indicators and stroke has not been fully investigated. The aim of this study was to investigate the relationship between IR and sarcopenia and the risk of new-onset stroke.

METHODS

Using longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018, Cox proportional hazards models were used to determine the association between IR surrogate indicators and sarcopenia status with stroke incidence.

RESULTS

In the present study, during a median 7 years of follow-up, we included 7009 middle-aged and elderly residents, of whom 515 presented with stroke incidence. After adjustment for potential confounders, both baseline IR surrogates and sarcopenia independently predicted stroke risk. In addition, co-morbidities had a higher risk of stroke than other groups. The positive association between TyG-WC and sarcopenia on stroke risk was particularly significant [HR (95% CI): 2.03 (1.52, 2.70)]. In subgroups of different ages and sexes, the combination of IR and sarcopenia is associated with the highest risk of stroke.

CONCLUSIONS

We found that IR and sarcopenia synergistically increase the incidence of stroke in older adults. This finding provides new perspectives for stroke detection and intervention and highlights the importance of early detection and management of IR and sarcopenia in older adults.

Casual associations between brain structure and sarcopenia: A large-scale genetic correlation and mendelian randomization study

Sarcopenia presenting a critical challenge in population-aging healthcare. The elucidation of the interplay between brain structure and sarcopenia necessitates further research. The aim of this study is to explore the casual association between brain structure and sarcopenia. Linkage disequilibrium score regression (LDSC) was conducted to estimate the genetic correlations; MR was then performed to explore the causal relationship between Brain imaging-derived phenotypes (BIDPs) and three sarcopenia-related traits: handgrip strength, walking pace, and appendicular lean mass (ALM). The main analyses were conducted using the inverse-variance weighted method. Moreover, weighted median and MR-Egger were conducted as sensitivity analyses. Genetic association between 6.41% of BIDPs and ALM was observed, and 4.68% of BIDPs exhibited causal MR association with handgrip strength, 2.11% of BIDPs were causally associated with walking pace, and 2.04% of BIDPs showed causal association with ALM. Volume of ventromedial hypothalamus was associated with increased odds of handgrip strength (OR: 1.18, 95% CI: 1.02 to 1.37) and ALM (OR: 1.05, 95% CI: 1.01 to 1.09). Mean thickness of G-pariet-inf-Angular was associated with decreased odds of handgrip strength (OR: 0.83, 95% CI: 0.70 to 0.97) and walking pace (OR: 0.97, 95% CI: 0.93 to 0.99). As part of the brain structure forward causally influences sarcopenia, which may provide new perspectives for the prevention of sarcopenia and offer valuable insights for further research on the brain-muscle axis.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Research Progress on Patients of Esophageal Cancer Complicated with Sarcopenia

Aims/Background The application of immunochemotherapy has significantly enhanced the quality of life and overall survival of patients with esophageal cancer. Sarcopenia, which is increasingly prevalent in these patients, markedly affects prognosis, but can be reversed by appropriate and effective treatment. Methods The narrative review was conducted on PubMed using the keywords ("esophageal" or "esophagus" and "sarcopenia"). Results This article reviews the measurement, timing, and intervention strategies for sarcopenia in patients with esophageal cancer. It summarizes the evaluation indicators of skeletal muscle loss in these patients, analyzes the barriers to intervention for frailty among esophageal cancer patients, and proposes corresponding countermeasures. Conclusion Patients with esophageal cancer often suffer from severe sarcopenia. Clinical intervention is crucial in addressing this issue.

Age, sex, and APOE gene-specific associations between dynapenic obesity and dementia in a large cohort

OBJECTIVE

To investigate the associations between dynapenic obesity and the risk of dementia, and the modifying effects of age, sex, and the APOE gene, using a large population-based cohort.

METHODS

279,884 participants aged 55 and above from the UK Biobank were included. The participants were classified into four categories based on body mass index and hand grip strength: healthy, obesity, dynapenia, and dynapenic obesity. The incident dementia was identified based on linked hospital records and death register data. Cox proportional hazards regression models were used to estimate the associations, followed by age-, sex-, and apolipoprotein E (APOE) gene-stratified analyses.

RESULTS

During the median follow-up of 12.4 years, 5,170 (1.8%) participants developed dementia. Compared with the healthy group, participants with dynapenic obesity had 67% higher dementia risk (hazard ratio [HR]: 1.67, 95% confidence interval [CI]: 1.44-1.94). Compared with the healthy group, higher risks of dementia in participants with dynapenic obesity were respectively observed in male (HR: 2.03, 95% CI: 1.65-2.50), younger (<65 years, HR: 1.97, 95% CI: 1.55-2.50), and non-ε4-carrier (HR: 1.97, 95% CI: 1.60-2.44) (all P for interaction <0.05). In participants under 65 years and non-ε4-carrier, those with dynapenic obesity had the highest risk of dementia (HR: 2.63, 95% CI: 1.91-3.62), compared with the healthy group (P for second order interaction = 0.026).

CONCLUSIONS

Dynapenic obesity is associated with increased risks of dementia, especially in participants under 65 years and non-ε4-carrier, suggesting the importance of managing dynapenic obesity in the prevention of cognition-related disorders.

Association between patients with migraine and sarcopenia: A retrospective study

Recently, interest in sarcopenia has been increasing in patients with various neurological diseases. Thus, we investigated the presence of sarcopenia in patients with episodic migraine (EM) based on temporal muscle thickness (TMT). This was a retrospectively observational study following STROBE guidelines. We enrolled patients with EM and healthy controls. Both groups underwent brain magnetic resonance imaging, including three-dimensional T1-weighted imaging. We calculated the TMT using T1-weighted imaging, which is a marker for sarcopenia. We compared TMT between patients with EM and healthy controls, and analyzed it according to presence of migraine aura. We retrospectively enrolled 82 patients with EM and 53 healthy controls. TMT was not different between patients with EM and healthy controls (10.804 ± 2.045 mm in patients with EM vs 10.721 ± 1.547 mm in healthy controls, P = .801). Furthermore, TMT was not different according to presence of migraine aura in patients with EM (10.994 ± 2.016 mm in patients with migraine aura vs 10.716 ± 2.071 mm in those without, P = .569). There were no correlations between TMT and clinical characteristics in patients with EM, including age, age of onset, duration of migraine, headache intensity, and headache frequency. This study found no statistical difference in TMT between patients with EM and healthy controls or between patients with EM with and without aura. These findings suggest that there is no evidence of sarcopenia in patients with EM.

Bidirectional Association between Sarcopenia and Depressive Symptoms among Chinese Middle- and Older-Aged Adults: Longitudinal Observational Study

BACKGROUND

The study aimed to examine the bidirectional relationship between sarcopenia and depressive symptoms in a national, community-based cohort study, despite the unclear temporal sequence demonstrated previously.

METHODS

Data were derived from four waves (2011 baseline and 2013, 2015, and 2018 follow-ups) of the China Health and Retirement Longitudinal Study (CHARLS). A total of 17,708 participants aged 45 years or older who had baseline data on both sarcopenia status and depressive symptoms in 2011 were included in the study. For the two cohort analyses, a total of 8092 adults without depressive symptoms and 11,292 participants without sarcopenia in 2011 were included. Sarcopenia status was defined according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria. Depressive symptoms were defined as a score of 20 or higher on the 10-item Center for Epidemiologic Studies Depressive Scale (CES-D-10). Cox proportional hazard regression models were conducted to examine the risk of depressive symptoms and sarcopenia risk, while cross-lagged panel models were used to examine the temporal sequence between depressive symptoms and sarcopenia over time.

RESULTS

During a total of 48,305.1 person-years follow-up, 1262 cases of incident depressive symptoms were identified. Sarcopenia exhibited a dose-response relationship with a higher risk of depressive symptoms (HR = 1.7, 95%CI: 1.2-2.3 for sarcopenia, and HR = 1.5, 95%CI: 1.2-1.8 for possible sarcopenia, p trend < 0.001). In the second cohort analysis, 240 incident sarcopenia cases were identified over 39,621.1 person-years. Depressive symptoms (HR = 1.5, 95%CI: 1.2-2.0) are significantly associated with a higher risk of developing sarcopenia after multivariable adjustment (p < 0.001, Cross-lagged panel analyses demonstrated that depressive symptoms were associated with subsequent sarcopenia (β = 0.003, p < 0.001). Simultaneously, baseline sarcopenia was also associated with subsequent depressive symptoms (β = 0.428, p < 0.001).

CONCLUSION

This study identified a bidirectional relationship between depressive symptoms and sarcopenia. It seems more probable that baseline sarcopenia is associated with subsequent depressive symptoms in a stronger pattern than the reverse pathway. The interlinkage indicated that maintaining normal muscle mass and strength may serve as a crucial intervention strategy for alleviating mood disorders.

The original scores of traditional Chinese medicine constitutions are risk and diagnostic factors in middle-aged and older adults with sarcopenia

Objective

Sarcopenia is a geriatric syndrome that occurs with age and is characterized by a gradual decline in muscle mass, power, and functionality. It serves as a prominent contributor to frailty, disability, and mortality among older individuals. Currently, no standardized global guidelines exist for the diagnosis of sarcopenia. This study aimed to establish the correlation between sarcopenia and the constitutions of traditional Chinese medicine (TCM), considering the connection between physical functioning and sarcopenia.

Methods

A total of 1441 participants in this study were diagnosed with sarcopenia. The Asian Working Group for Sarcopenia (AWGS) proposed a sarcopenia definition algorithm. To determine the constitution of each participant, classification and determination standards were used in traditional Chinese medicine. This study evaluated the demographics, lifestyles, and self-reported medical history of individuals diagnosed with sarcopenia through a self-administered questionnaire. The constitution of the participants was determined using TCM classification and determination standards. Subsequently, we analyzed the results of univariate analysis and multivariate regression and constructed a receiver operating characteristic (ROC) curve.

Results

Participants who were diagnosed with sarcopenia had substantially lower original Neutral constitution scores (P < 0.050). In comparison to those without sarcopenia, individuals with sarcopenia exhibited notably elevated original Qi-deficiency, Yang-deficiency, Yin-deficiency, Blood-stagnation, and Qi-stagnation scores in contrast to those in the healthy group (P < 0.050). The identified risk factors associated with sarcopenia included the following: Neutral (OR = 0.903), Qi-deficiency (in males, OR = 1.126), Yang-deficiency (OR = 1.062), Phlegm-dampness (in males, OR = 0.833), and Blood-stagnation (in females, OR = 1.089). The highest area under the curve (AUC) was observed for the original neutral constitution score, followed by the Yang-deficiency and blood-stagnation scores (0.644, 0.613, and 0.611, respectively). Additionally, the AUC for the combined original scores of all nine constitutions among males reached 0.778.

Conclusions

In this cross-sectional study of older people with higher original Qi-deficiency, Yin deficiency, Yang-deficiency, Blood-stagnation, and Qi-stagnation were associated with sarcopenia. Notably, various TCM constitutions are significantly linked to sarcopenia. There was a significant occurrence of various body constitution types among individuals diagnosed with sarcopenia. The mixture of the nine original constitution scores exhibited good diagnostic performance for sarcopenia in males.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Sarcopenia in subjects with Alzheimer's disease: prevalence and comparison of agreement between EGWSOP1, EGWSOP2, and FNIH criteria

BACKGROUND

Sarcopenia is an age-related clinical syndrome characterized by the progressive loss of muscle mass and muscle strength. It appears to be closely linked to dementia, particularly Alzheimer's disease (AD); however, its prevalence among AD patients remains unclear. In this study, we assessed differences in sarcopenia prevalence between non-demented individuals and AD patients. Moreover, we assessed sex-specific differences in sarcopenia prevalence and explored the diagnostic value of the Muscle Quality Index (MQI) for diagnosing sarcopenia among AD patients.

METHOD

Cross-sectional study including 145 patients with probable AD and 51 older adults with normal cognition. Sarcopenia was diagnosed according to the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP1 and EWGSOP2) and of the Foundation for the National Institutes of Health (FNIH). The MQI was computed as the ratio of handgrip strength to skeletal muscle mass.

RESULTS

No significant difference in sarcopenia prevalence was observed between AD patients and controls. Prevalence ranged from 3.4 to 23.4% in AD patients and from 2 to 11.8% in controls, depending on diagnostic criteria. Prevalence was higher using EWGSOP1 and decreased using EWGSOP2 and FNIH. Prevalence was higher in males than in females with AD. The MQI was lower in AD patients than in controls (95%CI: - 0.23, - 0.05, p < 0.001), but displayed poor diagnostic accuracy in identifying sarcopenia cases.

CONCLUSIONS

AD patients and controls show comparable sarcopenia prevalence. Sarcopenia prevalence is higher in males than females among AD patients and higher when using EWGSOP1 compared to FNIH and EWGSOP2 criteria.

Association of vitamins B1 and B2 intake with early-onset sarcopenia in the general adult population of the US: a cross-sectional study of NHANES data from 2011 to 2018

Background

Early-onset sarcopenia refers to the progressive loss of muscle mass and function that occurs at an early age. This condition perpetuates the vicious cycle of muscle loss and is associated with adverse outcomes. It is important to identify the contributing factors for early intervention and prevention. While diet is known to impact muscle mass, the association of B vitamins with early-onset sarcopenia remains unexplored.

Objectives

To investigate the association of B vitamins intake with early-onset sarcopenia risk in a cross-sectional study.

Methods

We conducted data analysis on a total of 8,711 participants aged between 20 and 59 years who took part in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. Early-onset sarcopenia was defined as a SMI measured by DXA that was one standard deviation below the sex-specific mean of the reference population. B vitamins intake (B1, B2, B3, B6, B9, and B12) was assessed by 24-h dietary recall. We used weighted multiple logistic regression and RCS models to estimate the OR and 95% CI of sarcopenia by B vitamins intake, adjusting for demographic, physical, lifestyle, comorbidities, and nutritional covariates.

Results

Higher intake of vitamin B1 was associated with a 22% lower sarcopenia risk (OR = 0.78, CI = 0.63-0.97, p = 0.022), and higher intake of vitamin B2 with a 16% lower risk (OR = 0.84, CI = 0.74-0.97, p = 0.012) in both genders. Gender-specific analyses showed a 28% reduction in sarcopenia risk among males with each additional mg of vitamin B1 intake (OR = 0.72, CI = 0.52-0.97, p = 0.038), and a 26% decrease among females with each additional mg of vitamin B2 intake (OR = 0.74, CI = 0.57-0.96, p = 0.021). No significant differences were found between vitamin B2 and males, or between vitamin B1 and females. The RCS model suggested a nonlinear relationship between vitamin B2 intake and sarcopenia risk (POverall = 0.001, PNonlinear = 0.033), with a plateau effect above 3 mg/d.

Conclusion

Higher intake of vitamin B1 and B2 may lower the risk of early-onset sarcopenia, with gender differences. This suggests the potential of nutritional intervention by increasing these vitamins intake through diet and supplements. Further research is warranted to elucidate the mechanisms and design targeted interventions.

Clinical Impact and Risk Factors of Seizure After Liver Transplantation: A Nested Case-Control Study

Seizures are a frequent neurological consequence following liver transplantation (LT), however, research on their clinical impact and risk factors is lacking. Using a nested case-control design, patients diagnosed with seizures (seizure group) within 1-year post-transplantation were matched to controls who had not experienced seizures until the corresponding time points at a 1:5 ratio to perform survival and risk factor analyses. Seizures developed in 61 of 1,243 patients (4.9%) at median of 11 days after LT. Five-year graft survival was significantly lower in the seizure group than in the controls (50.6% vs. 78.2%, respectively, p < 0.001) and seizure was a significant risk factor for graft loss after adjusting for variables (HR 2.04, 95% CI 1.24-3.33). In multivariable logistic regression, body mass index <23 kg/m2, donor age ≥45 years, intraoperative continuous renal replacement therapy and delta sodium level ≥4 mmol/L emerged as independent risk factors for post-LT seizure. Delta sodium level ≥4 mmol/L was associated with seizures, regardless of the severity of preoperative hyponatremia. Identifying and controlling those risk factors are required to prevent post-LT seizures which could result in worse graft outcome.

Development and Validation of Estimation Equations for Appendicular Skeletal Muscle Mass in Chinese Community-Dwelling Older Adults

Purpose

This study aimed to establish equations for estimating muscle mass through anthropometric parameters or together with physical function parameters in the community-dwelling older adults, providing a simple way of muscle mass assessment.

Methods

In this cross-sectional descriptive study, a total of 1537 older adults were recruited from the community and accepted the measurements of height, weight, upper arm and calf circumferences, grip strength, and walking speed. Body composition including appendicular skeletal muscle mass (ASM) was measured using bioelectrical impedance analysis (BIA). Participants were randomly divided into the development or validation group. Stepwise multiple linear regression was applied to develop equations in the development group. Thereafter, Pearson correlation coefficients, Bland-Altman plots, paired t-test, intraclass correlation coefficient (ICC) and paired-samples t-tests were used to assess the validity of the equations.

Results

All parameters were significantly correlated with ASM (r = 0.195~0.795, P < 0.001) except for the age in the validation group (P = 0.746). The most optimal anthropometric equation was: [adjusted R2 = 0.911, standard error of the estimate (SEE) = 1.311, P < 0.001]. Comparatively speaking, this equation showed high correlation coefficient (r = 0.951, P < 0.001) and ICC (ICC = 0.950, P < 0.001). No significant differences were found between BIA-measured ASM and the estimated ASM. The Bland-Altman plot showed that the mean difference between the estimated ASM and BIA-measured ASM was 0 kg and the limits of agreement of ASM was -2.70~2.60 kg. Furthermore, inclusion of physical function did not significantly improve the adjusted R2 and SEE.

Conclusion

The anthropometric equation offers a practical alternative simple and dependable method for estimating ASM in community-dwelling older adults.

Phenotype validation of the Korean working group on sarcopenia guideline

BACKGROUND

This study aimed to validate the proposed Korean Working Group on Sarcopenia (KWGS) guideline, which introduces the concept of functional sarcopenia, in older Korean adults.

METHODS

Data from the Aging Study of Pyeongchang Rural Area, a longitudinal cohort of community-dwelling older adults, were utilized to compare frailty status and institutionalization-free survival among participants according to sarcopenia status. Based on the KWGS guideline, severe sarcopenia was defined as low muscle mass and strength with slow gait speed; sarcopenia (not severe) was defined as low muscle mass with low muscle strength or slow gait speed; and functional sarcopenia was defined as low muscle strength and slow gait speed without low muscle mass.

RESULTS

Among the 1302 participants, 329 (25.3 %) had severe sarcopenia, 147 (11.3 %) had sarcopenia (not severe), and 277 (21.3 %) had functional sarcopenia. Frailty was significantly greater in participants with any phenotype of sarcopenia than in those without sarcopenia. Additionally, participants with functional sarcopenia were frailer than those with sarcopenia (not severe). Furthermore, the rates of institutionalization and mortality were higher in participants with any phenotype of sarcopenia than in those without sarcopenia. There was no statistical difference between the rates of sarcopenia (not severe) and those with functional sarcopenia. These findings remained consistent after adjusting for age and sex.

CONCLUSIONS

Each phenotype according to the KWGS guideline was associated with significantly greater frailty and increased risk of institutionalization and mortality. Functional sarcopenia was associated with greater frailty and had comparable prognosis with sarcopenia (not severe).

Sarcopenia, frailty prevalence, and related factors in patients with stroke: A cross-sectional analytical study from Turkey

BACKGROUND

Sarcopenia and frailty may develop at varying rates depending on the metabolic, structural, and functional changes in the muscle structure after stroke.

OBJECTIVE

To evaluate the prevalence of sarcopenia and frailty in patients with stroke and affecting clinical parameters.

METHODS

This was a cross-sectional and analytical study. Twenty-six (49.1%) women and 27 men (50.9%) with stroke with an average age of 60.2 ± 10.3 (median = 62) years were included in the study. To evaluate physical performance, balance, and mobility, we used the 4-meter walk test (4-MWT), timed up and go test, chair sit and stand test, and the Berg Balance Scale (BBS). Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia 2019 criteria. The SARC-F scale was used for sarcopenia.

RESULTS

The average stroke duration was 21.6 ± 18.2 months. Prefrailty was present in 14 (26.4%) patients, frailty was present in 34 (64.2%) patients, and two (3.8%) patients were normal. Sarcopenia was detected in 28 (52.8%) patients. According to handgrip strength, the prevalence of low muscle strength was 17% (n= 9). In the sarcopenic group, female sex (p= 0.005) was more frequent, 4-MWT was longer (p= 0.003), chair stand test results were lower (p< 0.001), the clinical frailty scale (CFS) was higher (p< 0.001), fall risk was higher compared with the BBS (p< 0.001), there was lower HG strength (p= 0.009), lower malnutrition scores (PNI, prognostic nutritional index, p< 0.001), and lower lymphocyte counts (p= 0.037). EAT-10 scores and dysphagia presence (p= 0.026), the presence of malnutrition (p< 0.021) and Nottingham Health Profile score (p< 0.001) were higher in the sarcopenic group.

CONCLUSION

Sarcopenia and frailty frequently develop in patients with chronic stroke, with low lymphocyte counts, physical performance, muscle strength, and mobility and balance scores, and it is associated with poor prognostic factors including high disease severity, dysphagia, malnutrition, risk of falling, and poor quality of life.

[Sarcopenia as a non-motor symptom of Parkinson's disease]

Sarcopenia is a progressive generalized skeletal muscle disease that is accompanied by an accelerated loss of muscle mass and function, affecting the quality of life and the ability to perform self-care. The prevalence of sarcopenia in the world today ranges from 10 to 25%, which represents a certain danger as it is a prognostic factor for possible injury and increased disability in the elderly population. Sarcopenia often accompanies a large number of different diseases, including neurodegenerative ones, so it is actively studied in this category of patients, for example, as one of the early symptoms of Parkinson's disease (PD). PD and sarcopenia have overlapping pathophysiological mechanisms of muscle fiber loss: inflammation, muscle autophagy, oxidative stress and apoptosis. Loss of muscle mass due to malnutrition is common in PD. According to some studies, the prevalence of sarcopenia in PD varies from 6 to 55.8%; weakness and sarcopenia are more common in patients with PD than in society as a whole, which is associated with an unfavorable course of the disease. The presence of both diseases simultaneously in one patient can impose certain restrictions on the treatment of the patient, worsen his physical and mental condition, which determines the need for early detection of sarcopenia in patients with PD.

The Relationship Between Sarcopenia And Proteinuria, What Do We Know?

Sarcopenia is one of the most common geriatric syndromes in the elderly. It is defined as a decrease in muscle mass and function, and it can lead to physical disability, falls, poor quality of life, impaired immune system, and death. It is known that, the frequency of sarcopenia increases in the kidney patient population compared to healthy individuals. Although it is known that kidney disease can lead to sarcopenia; our knowledge of whether sarcopenia causes kidney disease is limited. Prior studies have suggested that protein energy wasting may be a risk of de novo CKD. Proteinuria is an important manifestation of kidney disease and there is a relationship between sarcopenia and proteinuria in diabetes, geriatric population, kidney transplant, and nephrotic syndrome. Does proteinuria cause sarcopenia or vice versa? Are they both the results of common mechanisms? This issue is not clearly known. In this review, we examined the relationship between sarcopenia and proteinuria in the light of other studies.

A Biomechanical Simulation of Forearm Flexion Using the Finite Element Approach

Upper limb movement is vital in daily life. A biomechanical simulation of the forearm with consideration of the physiological characteristics of the muscles is instrumental in gaining deeper insights into the upper limb motion mechanisms. In this study, we established a finite element model of the forearm, including the radius, biceps brachii, and tendons. We simulated the motion of the forearm resulting from the contraction of the biceps brachii by using a Hill-type transversely isotropic hyperelastic muscle model. We adjusted the contraction velocity of the biceps brachii muscle in the simulation and found that a slower muscle contraction velocity facilitated forearm flexion. Then, we changed the percentage of fast-twitch fibers, the maximum muscle strength, and the neural excitation values of the biceps brachii muscle to investigate the forearm flexion of elderly individuals. Our results indicated that reduced fast-twitch fiber percentage, maximum muscle strength, and neural excitation contributed to the decline in forearm motion capability in elderly individuals. Additionally, there is a threshold for neural excitation, below which, motion capability sharply declines. Our model aids in understanding the role of the biceps brachii in forearm flexion and identifying the causes of upper limb movement disorders, which is able to provide guidance for enhancing upper limb performance.

Causality between sarcopenia-related traits and major depressive disorder: A bi-directional, two-sample Mendelian randomized study

Observational studies have demonstrated an association between sarcopenia and depression. However, these studies may be influenced by confounding factors, and the causal relationship between sarcopenia and major depressive disorder (MDD) remains unclear. This study aimed to apply the Mendelian randomization (MR) method to address confounding factors and assess the causal effect of sarcopenia on MDD. A two-way, two-sample MR method was employed in this study. Instrumental variables of genome-wide significance level were obtained from the open large-scale genome-wide association study summary data. MR analysis was conducted using inverse variance weighted, MR-Egger, and weighted median methods. The reliability of the results was verified using the heterogeneity test, pleiotropy test, and leave-one-out method for sensitivity analysis. Grip strength (right-hand grip strength: odds ratio [OR] = 0.880, 95% confidence interval [CI] 0.786-0.987, P = .027; left-hand grip strength: OR = 0.814, 95% CI 0.725-0.913, P < .001) and usual walking pace (OR = 0.673, 95% CI 0.506-0.896, P = .007) exhibited a direct causal effect on MDD. MDD had a significant causal effect on appendicular lean mass (β = -0.065, 95% CI -0.110, -0.019, P = .005). There was a causal relationship between sarcopenia-related traits and MDD. Loss of muscle strength, rather than skeletal muscle mass, is correlated with an increased risk of MDD. Furthermore, individuals with MDD are more likely to experience loss of skeletal muscle mass.

Surface Electrical Impedance Myography Detects Skeletal Muscle Atrophy in Aged Wildtype Zebrafish and Aged gpr27 Knockout Zebrafish

Throughout a vertebrate organism's lifespan, skeletal muscle mass and function progressively decline. This age-related condition is termed sarcopenia. In humans, sarcopenia is associated with risk of falling, cardiovascular disease, and all-cause mortality. As the world population ages, projected to reach 2 billion older adults worldwide in 2050, the economic burden on the healthcare system is also projected to increase considerably. Currently, there are no pharmacological treatments for sarcopenia, and given the long-term nature of aging studies, high-throughput chemical screens are impractical in mammalian models. Zebrafish is a promising, up-and-coming vertebrate model in the field of sarcopenia that could fill this gap. Here, we developed a surface electrical impedance myography (sEIM) platform to assess skeletal muscle health, quantitatively and noninvasively, in adult zebrafish (young, aged, and genetic mutant animals). In aged zebrafish (~85% lifespan) as compared to young zebrafish (~20% lifespan), sEIM parameters (2 kHz phase angle, 2 kHz reactance, and 2 kHz resistance) robustly detected muscle atrophy (p < 0.000001, q = 0.000002; p = 0.000004, q = 0.000006; p = 0.000867, q = 0.000683, respectively). Moreover, these same measurements exhibited strong correlations with an established morphometric parameter of muscle atrophy (myofiber cross-sectional area), as determined by histological-based morphometric analysis (r = 0.831, p = 2 × 10-12; r = 0.6959, p = 2 × 10-8; and r = 0.7220; p = 4 × 10-9, respectively). Finally, the genetic deletion of gpr27, an orphan G-protein coupled receptor (GPCR), exacerbated the atrophy of skeletal muscle in aged animals, as evidenced by both sEIM and histology. In conclusion, the data here show that surface EIM techniques can effectively discriminate between healthy young and sarcopenic aged muscle as well as the advanced atrophied muscle in the gpr27 KO animals. Moreover, these studies show how EIM values correlate with cell size across the animals, making it potentially possible to utilize sEIM as a "virtual biopsy" in zebrafish to noninvasively assess myofiber atrophy, a valuable measure for muscle and gerontology research.

Causality between sarcopenia and diabetic nephropathy: a bidirectional Mendelian randomization study

Background and purpose

Observational studies have shown that sarcopenia and diabetic nephropathy (DN), are closely related; however, the causal relationship is unclear. This study aims to address this issue using a bidirectional Mendelian randomization (MR) study.

Methodology

We data from genome-wide association studies including appendicular lean mass (n = 244,730), grip strength (right: n = 461,089, left: n = 461026), walking speed (n = 459,915), and DN (3283 cases and 181,704 controls) to conduct a bidirectional MR study. First, we conducted a Forward MR analysis to evaluate the causality of sarcopenia on the risk of DN from the genetic perspective with appendicular lean mass, grip strength, and walking speed as exposure and DN as the outcome. Then, DN as the exposure, we performed a Reverse MR analysis to determine whether DN impacted the appendicular lean mass, grip strength, and walking speed of the appendices. Finally, a series of sensitivity studies, such as heterogeneity tests, pleiotropy evaluations, and Leave-one-out analyses, were conducted to assess the MR analysis's accuracy further.

Results

According to a forward MR analysis, a genetically predicted decrease in appendicular lean mass is associated with an increased risk of developing DN risk (inverse variance weighting[IVW]: odd ratio [OR] = 0.863, 95% confidence interval [CI] 0.767-0.971; P = 0.014). According to reverse MR results, grip strength decreased as DN progressed (IVW: right β = 0.003, 95% CI: - 0.021 to - 0.009, P = 5.116e-06; left β = 0.003, 95% CI: - 0.024 to - 0.012, P = 7.035e-09). However, the results of the other MR analyses were not statistically different.

Conclusion

Notably, our findings suggest that the causal relationship between sarcopenia and DN cannot be generalized. According to analysis of the individual characteristic factors of sarcopenia, reducing in appendicular lean mass increases the risk of developing DN and DN is linked to reduced grip strength. But overall, there is no causal relationship between sarcopenia and DN, because the diagnosis of sarcopenia cannot be determined by one of these factors alone.