A Review of Sarcopenia Pathophysiology, Diagnosis, Treatment and Future Direction

Sarcopenia and aortic valve disease

Valvular heart disease, including calcific or degenerative aortic stenosis (AS), is increasingly prevalent among the older adult population. Over the last few decades, treatment of severe AS has been revolutionised following the development of transcatheter aortic valve replacement (TAVR). Despite improvements in outcomes, older adults with competing comorbidities and geriatric syndromes have suboptimal quality of life outcomes, highlighting the cumulative vulnerability that persists despite valve replacement. Sarcopenia, characterised by loss of muscle strength, mass and function, affects 21%-70% of older adults with AS. Sarcopenia is an independent predictor of short-term and long-term outcomes after TAVR and should be incorporated as a prognostic marker in preprocedural planning. Early diagnosis and treatment of sarcopenia may reduce morbidity and mortality and improve quality of life following TAVR. The adverse effects of sarcopenia can be mitigated through resistance training and optimisation of nutritional status. This is most efficacious when administered before sarcopenia has progressed to advanced stages. Management should be individualised based on the patient's wishes/preferences, care goals and physical capability. Exercise during the preoperative waiting period may be safe and effective in most patients with severe AS. However, future studies are needed to establish the benefits of prehabilitation in improving quality of life outcomes after TAVR procedures.

Tracking the Plasma C-Terminal Agrin Fragment as a Biomarker of Neuromuscular Decline in 18- to 87-Year-Old Men

OBJECTIVES

Plasma C-terminal agrin-fragment-22 (CAF22), a breakdown product of neuromuscular junction, is a potential biomarker of muscle loss. However, its levels from adolescence to octogenarians are unknown.

METHODS

We evaluated young (18-34 years, n = 203), middle-aged (35-59 years, n = 163), and old men (60-87 years, n = 143) for CAF22, handgrip strength (HGS), appendicular skeletal-mass index (ASMI), and gait speed.

RESULTS

We found an age-associated increase in CAF22 from young (100.9 ± 29 pmol) to middle-aged (128.3 ± 38.7 pmol) and older men (171.5 ± 35.5 pmol) (all p<0.05). This was accompanied by a gradual reduction in HGS (37.7 ± 6.1 kg, 30.2 ± 5.2 kg, and 26.6 ± 4.7 kg, for young, middle-aged, and old men, respectively), ASMI (8.02 ± 1.02 kg/m2, 7.65 ± 0.92 kg/m2, 6.87 ± 0.93 kg/m2, for young, middle-aged, and old men, respectively), and gait speed (1.29 ± 0.24 m/s, 1.05 ± 0.16 m/s, and 0.81 ± 0.13 m/s, for young, middle-aged, and old men, respectively). After adjustment for age, we found negative regressions of CAF22 with HGS (- 0.0574, p < 0.001) and gait speed (- 0.0162, p < 0.001) in the cumulative cohort. The receiver operating characteristics analysis revealed significant efficacy of plasma CAF22 in diagnosing muscle weakness (HGS < 27 kg) (middle-aged men; AUC = 0.731, 95% CI = 0.629-0.831, p < 0.001, Older men; AUC = 0.816, 95% CI = 0.761-0.833, p < 0.001), and low gait speed (0.8 m/s) (middle-aged men; AUC = 0.737, 95% CI = 0.602-0.871, p < 0.001, older men; AUC = 0.829, 95% CI = 0.772-0.886, p < 0.001), and a modest efficacy in diagnosing sarcopenia (middle-aged men; AUC = 0.701, 95% CI = 0.536-0.865, p = 0.032, older men; AUC = 0.822, 95% CI = 0.759-0.884, p < 0.001) in middle-aged and older men.

CONCLUSION

Altogether, CAF22 increases with advancing age and may be a reliable marker of muscle weakness and low gait speed.

Diagnostic and prognostic value of parameters of erector spinae in patients with uremic sarcopenia

AIM

This study aimed to investigate whether computed tomography (CT)-measured erector spinae parameters (ESPs) have diagnostic, severity assessment, and prognostic predictive value in uremic sarcopenia (US).

MATERIALS AND METHODS

A total of 202 uremic patients were enrolled and divided into two groups: a control group and a sarcopenia group. Sarcopenia was classified into two types: severe and nonsevere. The area, volume, and density of the erector spinae (ES) were measured using chest CT images, and the relevant ESP, including the erector spinae index (ESI), total erector spinae volume (TESV), erector spinae density (ESD), and erector spinae gauge (ESG) were calculated. The occurrence of adverse events was followed-up for 36 months. The diagnostic value and severity of US were determined using the receiver operating characteristic (ROC) curve. Survival curves diagnosed using CT were plotted and compared with the curve drawn using the gold standard. Cox regression analysis was used to identify independent risk factors associated with survival in US.

RESULTS

With an area under the curve (AUC) of 0.840 and 0.739, the combined ESP has diagnostic value and the ability to assess the severity of US. There was no significant difference in the survival curve between the combined ESP for the diagnosis of US and the gold standard (P > 0.05). ESI is a standalone predictor of survival in patients with US.

CONCLUSION

ESP measured by CT has diagnostic values for US and its severity, as well as being a predictive value for the prognosis of US.

Pleiotropic effects on Sarcopenia subphenotypes point to potential molecular markers for the disease

Sarcopenia is a progressive age-related muscle disease characterized by low muscle strength, quantity and quality, and low physical performance. The clinical overlap between these subphenotypes (reduction in muscle strength, quantity and quality, and physical performance) was evidenced, but the genetic overlap is still poorly investigated. Herein, we investigated whether there is a genetic overlap amongst sarcopenia subphenotypes in the search for more effective molecular markers for this disease. For that, a Bioinformatics approach was used to identify and characterize pleiotropic effects at the genome, loci and gene levels using Genome-wide association study results. As a result, a high genetic correlation was identified between gait speed and muscle strength (rG=0.5358, p=3.39 × 10-8). Using a Pleiotropy-informed conditional and conjunctional false discovery rate method we identified two pleiotropic loci for muscle strength and gait speed, one of them was nearby the gene PHACTR1. Moreover, 11 pleiotropic loci and 25 genes were identified for muscle mass and muscle strength. Lastly, using a gene-based GWAS approach three candidate genes were identified in the overlap of the three Sarcopenia subphenotypes: FTO, RPS10 and CALCR. The current study provides evidence of genetic overlap and pleiotropy among sarcopenia subphenotypes and highlights novel candidate genes and molecular markers associated with the risk of sarcopenia.

Prognostic impact of myosteatosis in patients with colorectal cancer undergoing curative surgery: an updated systematic review and meta-analysis

Background

Colorectal cancer (CRC) is a global health concern, and identifying prognostic factors can improve outcomes. Myosteatosis is fat infiltration into muscles and is a potential predictor of the survival of patients with CRC.

Methods

This systematic review and meta-analysis aimed to assess the prognostic role of myosteatosis in CRC. PubMed, Embase, and Cochrane CENTRAL were searched up to 1 August 2023, for relevant studies, using combinations of the keywords CRC, myosteatosis, skeletal muscle fat infiltration, and low skeletal muscle radiodensity. Case-control, prospective, and retrospective cohort studies examining the association between myosteatosis and CRC outcomes after curative intent surgery were eligible for inclusion. Primary outcomes were overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS).

Results

A total of 10 studies with a total of 9,203 patients were included. The pooled hazard ratio (HR) for OS (myosteatosis vs. no myosteatosis) was 1.52 [95% confidence interval (CI), 1.38-1.67); for CSS, 1.67 (95% CI, 1.40-1.99); and for DFS, 1.89 (95% CI, 1.35-2.65).

Conclusion

In patients with CRC undergoing curative intent surgery, myosteatosis is associated with worse OS, CSS, and DFS. These findings underscore the importance of evaluating myosteatosis in patients with CRC to improve outcomes.

Identification of shared gene signatures and pathways for diagnosing osteoporosis with sarcopenia through integrated bioinformatics analysis and machine learning

BACKGROUND

Prior studies have suggested a potential relationship between osteoporosis and sarcopenia, both of which can present symptoms of compromised mobility. Additionally, fractures among the elderly are often considered a common outcome of both conditions. There is a strong correlation between fractures in the elderly population, decreased muscle mass, weakened muscle strength, heightened risk of falls, and diminished bone density. This study aimed to pinpoint crucial diagnostic candidate genes for osteoporosis patients with concomitant sarcopenia.

METHODS

Two osteoporosis datasets and one sarcopenia dataset were obtained from the Gene Expression Omnibus (GEO). Differential expression genes (DEGs) and module genes were identified using Limma and Weighted Gene Co-expression Network Analysis (WGCNA), followed by functional enrichment analysis, construction of protein-protein interaction (PPI) networks, and application of a machine learning algorithm (least absolute shrinkage and selection operator (LASSO) regression) to determine candidate hub genes for diagnosing osteoporosis combined with sarcopenia. Receiver operating characteristic (ROC) curves and column line plots were generated.

RESULTS

The merged osteoporosis dataset comprised 2067 DEGs, with 424 module genes filtered in sarcopenia. The intersection of DEGs between osteoporosis and sarcopenia module genes consisted of 60 genes, primarily enriched in viral infection. Through construction of the PPI network, 30 node genes were filtered, and after machine learning, 7 candidate hub genes were selected for column line plot construction and diagnostic value assessment. Both the column line plots and all 7 candidate hub genes exhibited high diagnostic value (area under the curve ranging from 1.00 to 0.93).

CONCLUSION

We identified 7 candidate hub genes (PDP1, ALS2CL, VLDLR, PLEKHA6, PPP1CB, MOSPD2, METTL9) and constructed column line plots for osteoporosis combined with sarcopenia. This study provides reference for potential peripheral blood diagnostic candidate genes for sarcopenia in osteoporosis patients.

Frontiers in sarcopenia: Advancements in diagnostics, molecular mechanisms, and therapeutic strategies

The onset of sarcopenia is intimately linked with aging, posing significant implications not only for individual patient quality of life but also for the broader societal healthcare framework. Early and accurate identification of sarcopenia and a comprehensive understanding of its mechanistic underpinnings and therapeutic targets paramount to addressing this condition effectively. This review endeavors to present a cohesive overview of recent advancements in sarcopenia research and diagnosis. We initially delve into the contemporary diagnostic criteria, specifically referencing the European Working Group on Sarcopenia in Older People (EWGSOP) 2 and Asian Working Group on Sarcopenia (AWGS) 2019 benchmarks. Additionally, we elucidate comprehensive assessment techniques for muscle strength, quantity, and physical performance, highlighting tools such as grip strength, chair stand test, dual-energy X-ray Absorptiometry (DEXA), bioelectrical impedance analysis (BIA), gait speed, and short physical performance battery (SPPB), while also discussing their inherent advantages and limitations. Such diagnostic advancements pave the way for early identification and unequivocal diagnosis of sarcopenia. Proceeding further, we provide a deep-dive into sarcopenia's pathogenesis, offering a thorough examination of associated signaling pathways like the Myostatin, AMP-activated protein kinase (AMPK), insulin/IGF-1 Signaling (IIS), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways. Each pathway's role in sarcopenia mediation is detailed, underscoring potential therapeutic target avenues. From a mechanistic perspective, the review also underscores the pivotal role of mitochondrial dysfunction in sarcopenia, emphasizing elements such as mitochondrial oxidative overload, mitochondrial biogenesis, and mitophagy, and highlighting their therapeutic significance. At last, we capture recent strides made in sarcopenia treatment, ranging from nutritional and exercise interventions to potential pharmacological and supplementation strategies. In sum, this review meticulously synthesizes the latest scientific developments in sarcopenia, aiming to enhance diagnostic precision in clinical practice and provide comprehensive insights into refined mechanistic targets and innovative therapeutic interventions, ultimately contributing to optimized patient care and advancements in the field.

Probiotics Supplements Improve the Sarcopenia-Related Quality of Life in Older Adults with Age-Related Muscle Decline

A pathological increase in intestinal leak is implicated in age-associated muscle loss, termed sarcopenia, and reduced sarcopenia-related quality-of-life (SarQoL). However, the potential therapies remain elusive. We investigated the effects of probiotic supplementation on sarcopenia and SarQoL in geriatric older adults. We randomized sarcopenic men into placebo (age = 71.4 ± 3.9 years, n = 63) and probiotic (age = 73 ± 4.1 years, n = 60) groups for 16 weeks. The probiotic used was one capsule daily of Vivomix 112 billion for 16 weeks. We measured sarcopenia parameters of handgrip strength (HGS) and skeletal mass index (SMI), plasma zonulin (marker of the intestinal leak), and SarQoL using a targeted questionnaire. Probiotics improved the SarQoL scores for locomotion, functionality, and activities of daily living and prevented a decline in cumulative SarQoL observed in the placebo group (all p < 0.05). Probiotic supplementation also reduced plasma zonulin and marker of systemic bacterial load. These changes were accompanied by an increase in HGS and maintenance of gait speed in the probiotic group compared to the placebo group. Correlation analysis revealed significant associations of cumulative SarQoL scores with plasma zonulin and HGS in the probiotic group. Collectively, probiotics improved SarQoL and HGS by repairing pathological intestinal leak. Future studies may further dissect the relation between intestinal leak and SarQoL in older adults taking probiotics.

PGC-1α participates in regulating mitochondrial function in aged sarcopenia through effects on the Sestrin2-mediated mTORC1 pathway

BACKGROUND

Mitochondrial dysregulation in skeletal myocytes is considered a major factor in aged sarcopenia. In this study, we aimed to study the effects of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) on Sestrin2-mediated mechanistic target of rapamycin complex 1 (mTORC1) in aged skeletal muscles.

METHODS

C2C12 myoblasts were stimulated by 50 μM 7β-hydroxycholesterol (7β-OHC) to observe the changes of DNA damage, mitochondrial membrane potential (Δψm), mitochondrial ROS and PGC-1α protein. The PGC-1α silence in the C2C12 cells was established by siRNA transfection. The levels of DNA damage, Δψm, mitochondrial ROS, Sestrin2 and p-S6K1/S6K1 proteins were observed after the PGC-1α silence in the C2C12 cells. Recombinant Sestrin2 treatment was used to observe the changes of DNA damage, Δψm, mitochondrial ROS and p-S6K1/S6K1 protein in the 7β-OHC-treated or PGC-1α siRNA-transfected C2C12 cells. Wild-type (WT) mice and muscle-specific PGC-1α conditional knockout (MKO) mice, including young and old, were used to analyse the effects of PGC-1α on muscle function and the levels of Sestrin2 and p-S6K1 in the white gastrocnemius muscles. Recombinant Sestrin2 was administrated to analyse its effects on muscle function in the old WT mice and old MKO mice.

RESULTS

7β-OHC treatment induced DNA damage, mitochondrial dysfunction and decrease of PGC-1α protein in the C2C12 cells. PGC-1α silence also induced DNA damage and mitochondrial dysfunction in the C2C12 cells. Additionally, PGC-1α silence or 7β-OHC treatment decreased the levels of Sestrin2 and p-S6K1/S6K1 protein in the C2C12 cells. Recombinant Sestrin2 treatment significantly improved the DNA damage and mitochondrial dysfunction in the 7β-OHC-treated or PGC-1α siRNA-transfected C2C12 cells. At the same age, muscle-specific PGC-1α deficiency aggravated aged sarcopenia and decreased the levels of Sestrin2 and p-S6K1 in the white gastrocnemius muscles when compared to the WT mice. Recombinant Sestrin2 treatment improved muscle function and increased p-S6K1 levels in the old two genotypes.

CONCLUSION

This research demonstrates that PGC-1α participates in regulating mitochondrial function in aged sarcopenia through effects on the Sestrin2-mediated mTORC1 pathway.

Navigating the Intersection: Sarcopenia and Sarcopenic Obesity in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are intricate systemic conditions that can extend beyond the gastrointestinal tract through both direct and indirect mechanisms. Sarcopenia, characterized by a reduction in muscle mass and strength, often emerges as a consequence of the clinical course of IBDs. Indeed, sarcopenia exhibits a high prevalence in Crohn's disease (52%) and ulcerative colitis (37%). While computed tomography and magnetic resonance imaging remain gold-standard methods for assessing muscle mass, ultrasound is gaining traction as a reliable, cost-effective, and widely available diagnostic method. Muscle strength serves as a key indicator of muscle function, with grip strength test emerging nowadays as the most reliable assessment method. In IBDs, sarcopenia may arise from factors such as inflammation, malnutrition, and gut dysbiosis, leading to the formulation of the 'gut-muscle axis' hypothesis. This condition determines an increased need for surgery with poorer post-surgical outcomes and a reduced response to biological treatments. Sarcopenia and its consequences lead to reduced quality of life (QoL), in addition to the already impaired QoL. Of emerging concern is sarcopenic obesity in IBDs, a challenging condition whose pathogenesis and management are still poorly understood. Resistance exercise and nutritional interventions, particularly those aimed at augmenting protein intake, have demonstrated efficacy in addressing sarcopenia in IBDs. Furthermore, anti-TNF biological therapies showed interesting outcomes in managing this condition. This review seeks to furnish a comprehensive overview of sarcopenia in IBDs, elucidating diagnostic methodologies, pathophysiological mechanisms, and clinical implications and management. Attention will also be paid to sarcopenic obesity, exploring the pathophysiology and possible treatment modalities of this condition.

Chimeric Cell Therapies as a Novel Approach for Duchenne Muscular Dystrophy (DMD) and Muscle Regeneration

Chimerism-based strategies represent a pioneering concept which has led to groundbreaking advancements in regenerative medicine and transplantation. This new approach offers therapeutic potential for the treatment of various diseases, including inherited disorders. The ongoing studies on chimeric cells prompted the development of Dystrophin-Expressing Chimeric (DEC) cells which were introduced as a potential therapy for Duchenne Muscular Dystrophy (DMD). DMD is a genetic condition that leads to premature death in adolescent boys and remains incurable with current methods. DEC therapy, created via the fusion of human myoblasts derived from normal and DMD-affected donors, has proven to be safe and efficacious when tested in experimental models of DMD after systemic-intraosseous administration. These studies confirmed increased dystrophin expression, which correlated with functional and morphological improvements in DMD-affected muscles, including cardiac, respiratory, and skeletal muscles. Furthermore, the application of DEC therapy in a clinical study confirmed its long-term safety and efficacy in DMD patients. This review summarizes the development of chimeric cell technology tested in preclinical models and clinical studies, highlighting the potential of DEC therapy in muscle regeneration and repair, and introduces chimeric cell-based therapies as a promising, novel approach for muscle regeneration and the treatment of DMD and other neuromuscular disorders.

Exploration of a machine learning approach for diagnosing sarcopenia among Chinese community-dwelling older adults using sEMG-based data

BACKGROUND

In the practical application of sarcopenia screening, there is a need for faster, time-saving, and community-friendly detection methods. The primary purpose of this study was to perform sarcopenia screening in community-dwelling older adults and investigate whether surface electromyogram (sEMG) from hand grip could potentially be used to detect sarcopenia using machine learning (ML) methods with reasonable features extracted from sEMG signals. The secondary aim was to provide the interpretability of the obtained ML models using a novel feature importance estimation method.

METHODS

A total of 158 community-dwelling older residents (≥ 60 years old) were recruited. After screening through the diagnostic criteria of the Asian Working Group for Sarcopenia in 2019 (AWGS 2019) and data quality check, participants were assigned to the healthy group (n = 45) and the sarcopenic group (n = 48). sEMG signals from six forearm muscles were recorded during the hand grip task at 20% maximal voluntary contraction (MVC) and 50% MVC. After filtering recorded signals, nine representative features were extracted, including six time-domain features plus three time-frequency domain features. Then, a voting classifier ensembled by a support vector machine (SVM), a random forest (RF), and a gradient boosting machine (GBM) was implemented to classify healthy versus sarcopenic participants. Finally, the SHapley Additive exPlanations (SHAP) method was utilized to investigate feature importance during classification.

RESULTS

Seven out of the nine features exhibited statistically significant differences between healthy and sarcopenic participants in both 20% and 50% MVC tests. Using these features, the voting classifier achieved 80% sensitivity and 73% accuracy through a five-fold cross-validation. Such performance was better than each of the SVM, RF, and GBM models alone. Lastly, SHAP results revealed that the wavelength (WL) and the kurtosis of continuous wavelet transform coefficients (CWT_kurtosis) had the highest feature impact scores.

CONCLUSION

This study proposed a method for community-based sarcopenia screening using sEMG signals of forearm muscles. Using a voting classifier with nine representative features, the accuracy exceeds 70% and the sensitivity exceeds 75%, indicating moderate classification performance. Interpretable results obtained from the SHAP model suggest that motor unit (MU) activation mode may be a key factor affecting sarcopenia.

The causal relationship between sarcopenia-related traits and ischemic stroke: Insights from univariable and multivariable Mendelian randomization analyses

AIMS

The causal relationship between sarcopenia-related traits and ischemic stroke (IS) remains poorly understood. This study aimed to explore the causal impact of sarcopenia-related traits on IS and to identify key mediators of this association.

METHODS

We conducted univariable, multivariable two-sample, and two-step Mendelian randomization (MR) analyses using genome-wide association study (GWAS) data. This included data for appendicular lean mass (ALM), hand grip strength (HGS), and usual walking pace (UWP) from the UK Biobank, and IS data from the MEGASTROKE consortium. Additionally, 21 candidate mediators were analyzed based on their respective GWAS data sets.

RESULTS

Each 1-SD increase in genetically proxied ALM was associated with a 7.5% reduction in the risk of IS (95% CI: 0.879-0.974), and this correlation remained after controlling for levels of physical activity and adiposity-related indices. Two-step MR identified that six mediators partially mediated the protective effect of higher ALM on IS, with the most significant being coronary heart disease (CHD, mediating proportion: 39.94%), followed by systolic blood pressure (36.51%), hypertension (23.87%), diastolic blood pressure (15.39%), type-2 diabetes mellitus (T2DM, 12.71%), and low-density lipoprotein cholesterol (7.97%).

CONCLUSION

Our study revealed a causal protective effect of higher ALM on IS, independent of physical activity and adiposity-related indices. Moreover, we found that higher ALM could reduce susceptibility to IS partially by lowering the risk of vascular risk factors, including CHD, hypertension, T2DM, and hyperlipidemia. In brief, we elucidated another modifiable factor for IS and implied that maintaining sufficient muscle mass may reduce the risk of such disease.

Social network associated with depressed mood and sarcopenia among older adults in Taiwan

BACKGROUND

Social isolation is increasing in aging societies; however, its relationship with depressed mood and sarcopenia is not well studied. This study aims to examine the influence of social network on depressed mood and sarcopenia among community-dwelling older adults in Taiwan.

METHODS

We collected data from a sample of 981 older adults residing in the community. These individuals received government-subsidized preventive healthcare services for adults at a district hospital in Taipei in 2021. The social network of the older adults who participated was assessed using the Lubben Social Network Scale, while depressed mood was assessed using the Geriatric Depression Scale. The definition of sarcopenia used in this study was based on the 2019 Asian Working Group for Sarcopenia.

RESULTS

According to this study, sarcopenia was present in approximately 15 % of older adults. Multiple logistic regression analysis showed that older adults who had poor social network and did not meet the recommended 150 min of regular physical activity per week were more likely to have depressed mood. Additionally, older adults who were older, underweight, did not engage in regular physical activity, and had poor social network were more likely to have sarcopenia.

CONCLUSION

Poor social network was associated with increased risks of depressed mood and sarcopenia among older adults.

Emerging Therapeutic Strategies in Sarcopenia: An Updated Review on Pathogenesis and Treatment Advances

Sarcopenia is a prevalent degenerative skeletal muscle condition in the elderly population, posing a tremendous burden on diseased individuals and healthcare systems worldwide. Conventionally, sarcopenia is currently managed through nutritional interventions, physical therapy, and lifestyle modification, with no pharmaceutical agents being approved for specific use in this disease. As the pathogenesis of sarcopenia is still poorly understood and there is no treatment recognized as universally effective, recent research efforts have been directed at better comprehending this illness and diversifying treatment strategies. In this respect, this paper overviews the new advances in sarcopenia treatment in correlation with its underlying mechanisms. Specifically, this review creates an updated framework for sarcopenia, describing its etiology, pathogenesis, risk factors, and conventional treatments, further discussing emerging therapeutic approaches like new drug formulations, drug delivery systems, stem cell therapies, and tissue-engineered scaffolds in more detail.

Inflammaging in Multidrug-Resistant Sepsis of Geriatric ICU Patients and Healthcare Challenges

Multidrug-resistant sepsis (MDR) is a pressing concern in intensive care unit (ICU) settings, specifically among geriatric patients who experience age-related immune system changes and comorbidities. The aim of this review is to explore the clinical impact of MDR sepsis in geriatric ICU patients and shed light on healthcare challenges associated with its management. We conducted a comprehensive literature search using the National Center for Biotechnology Information (NCBI) and Google Scholar search engines. Our search incorporated keywords such as "multidrug-resistant sepsis" OR "MDR sepsis", "geriatric ICU patients" OR "elderly ICU patients", and "complications", "healthcare burdens", "diagnostic challenges", and "healthcare challenges" associated with MDR sepsis in "ICU patients" and "geriatric/elderly ICU patients". This review explores the specific risk factors contributing to MDR sepsis, the complexities of diagnostic challenges, and the healthcare burden faced by elderly ICU patients. Notably, the elderly population bears a higher burden of MDR sepsis (57.5%), influenced by various factors, including comorbidities, immunosuppression, age-related immune changes, and resource-limited ICU settings. Furthermore, sepsis imposes a significant economic burden on healthcare systems, with annual costs exceeding $27 billion in the USA. These findings underscore the urgency of addressing MDR sepsis in geriatric ICU patients and the need for tailored interventions to improve outcomes and reduce healthcare costs.

Restoration of epigenetic impairment in the skeletal muscle and chronic inflammation resolution as a therapeutic approach in sarcopenia

Sarcopenia is an age-associated loss of skeletal muscle mass, strength, and function, accompanied by severe adverse health outcomes, such as falls and fractures, functional decline, high health costs, and mortality. Hence, its prevention and treatment have become increasingly urgent. However, despite the wide prevalence and extensive research on sarcopenia, no FDA-approved disease-modifying drugs exist. This is probably due to a poor understanding of the mechanisms underlying its pathophysiology. Recent evidence demonstrate that sarcopenia development is characterized by two key elements: (i) epigenetic dysregulation of multiple molecular pathways associated with sarcopenia pathogenesis, such as protein remodeling, insulin resistance, mitochondria impairments, and (ii) the creation of a systemic, chronic, low-grade inflammation (SCLGI). In this review, we focus on the epigenetic regulators that have been implicated in skeletal muscle deterioration, their individual roles, and possible crosstalk. We also discuss epidrugs, which are the pharmaceuticals with the potential to restore the epigenetic mechanisms deregulated in sarcopenia. In addition, we discuss the mechanisms underlying failed SCLGI resolution in sarcopenia and the potential application of pro-resolving molecules, comprising specialized pro-resolving mediators (SPMs) and their stable mimetics and receptor agonists. These compounds, as well as epidrugs, reveal beneficial effects in preclinical studies related to sarcopenia. Based on these encouraging observations, we propose the combination of epidrugs with SCLI-resolving agents as a new therapeutic approach for sarcopenia that can effectively attenuate of its manifestations.

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.

The causal association between circulating cytokines with the risk of frailty and sarcopenia under the perspective of geroscience

Introduction

Circulating cytokines were considered to play a critical role in the initiation and propagation of sarcopenia and frailty from observational studies. This study aimed to find the casual association between circulating cytokines and sarcopenia and frailty from a genetic perspective by two-sample Mendelian randomization (MR) analysis.

Methods

Data for 41 circulating cytokines were extracted from the genome-wide association study dataset of 8,293 European participants. Inverse-variance weighted (IVW) method, MR-Egger, and weighted median method were applied to assess the relationship of circulating cytokines with the risk of aging-related syndromes and frailty. Furthermore, MR-Egger regression was used to indicate the directional pleiotropy, and Cochran's Q test was used to verify the potential heterogeneity. The "leave-one-out" method was applied to visualize whether there was a causal relationship affected by only one anomalous single-nucleotide polymorphisms.

Results

Genetic predisposition to increasing levels of interleukin-10 (IL-10), IL-12, and vascular endothelial growth factor (VEGF) was associated with the higher risk of low hand grip strength according to the IVW method [R = 1.05, 95% CI = 1.01-1.10, P = 0.028, false discovery rate (FDR)-adjusted P = 1.000; OR = 1.03, 95% CI = 1.00-1.07, P = 0.042, FDR-adjusted P = 0.784; OR = 1.02, 95% CI = 1.00-1.05, P = 0.038, FDR-adjusted P = 0.567]. Furthermore, genetically determined higher macrophage colony-stimulating factors (M-CSFs) were associated with a lower presence of appendicular lean mass (OR = 1.01, 95% CI = 1.00-1.02, P = 0.003, FDR-adjusted P = 0.103). Monokine induced by interferon-γ (MIG) and tumor necrosis factor-beta (TNF-β) were associated with a higher risk of frailty (OR = 1.03, 95% CI = 1.01-1.05, P < 0.0001, FDR-adjusted P = 0.012; OR = 1.01, 95% CI = 1.00-1.03, P = 0.013, FDR-adjusted P = 0.259). In this study, we did not find heterogeneity and horizontal pleiotropy between the circulating cytokines and the risk of frailty and sarcopenia.

Conclusion

Genetic predisposition to assess IL-10, IL-12, and VEGF levels was associated with a higher risk of low hand grip strength and M-CSF with the presence of appendicular lean mass. The high levels of TNF-β and MIG were associated with a higher risk of frailty. More studies will be required to explore the molecular biological mechanisms underlying the action of inflammatory factors.

A multifaceted and inclusive methodology for the detection of sarcopenia in patients undergoing bariatric surgery: an in-depth analysis of current evidence

Bariatric surgery is widely recognized as the most effective intervention for obesity and offers benefits beyond weight loss. However, not all patients achieve satisfactory weight loss, balanced changes in body composition, and resolution of comorbidities. Therefore, thorough pre- and postoperative evaluations are important to predict success and minimize adverse effects. More comprehensive assessments require broadening the focus beyond body weight and fat measurements to consider quantitative and qualitative evaluations of muscles. Introducing the concept of sarcopenia is useful for assessing the degradative and pathological changes in muscles associated with cardiometabolic function, physical performance, and other obesity-related comorbidities in patients undergoing bariatric surgery. However, there is currently no consensus or definition regarding the research and clinical use of sarcopenia in patients undergoing bariatric surgery. Therefore, this review aimed to define the concept of sarcopenia applicable to patients undergoing bariatric surgery, based on the consensus reached for sarcopenia in the general population. We also discuss the methods and significance of measuring muscle mass, quality, and strength, which are key variables requiring a comprehensive assessment.

Betaine attenuates age-related suppression in autophagy via Mettl21c/p97/VCP axis to delay muscle loss

Age-related impairment of autophagy accelerates muscle loss and lead to sarcopenia. Betaine can delay muscle loss as a dietary methyl donor via increasing S-adenosyl-L-methionine (SAM, a crucial metabolite for autophagy regulation) in methionion cycle. However, whether betaine can regulate autophagy level to attenuate degeneration in aging muscle remains unclear. Herein, male C57BL/6J young mice (YOU, 2-month-old), old mice (OLD, 15-month-old), and 2%-betaine-treated old mice (BET, 15-month-old) were employed and raised for 12 weeks. All mice underwent body composition examination and grip strength test before being sacrificed. Betaine alleviated age-related decline in muscle mass and strength. Meanwhile, betaine preserved the expression autophagy markers (Atg5, Atg7, LC3-II, and Beclin1) both at transcriptional and translational level during the aging process. RNA-sequencing results generated from mice gastrocnemius muscle found Mettl21c, a SAM-dependent autophagy-regulating methyltransferase, was significantly higher expressed in BET and YOU group. Results were further validated by qPCR and western bloting. In vitro, C2C12 cells with or without Mettl21c RNA interference were treated different concentration of betaine (0 mM, 10 mM) under methionine-starved condition. Compared with control group, betaine upregulated autophagy markers expression and autophagy flux. By increasing the SAM level, betaine facilitated trimethylation of p97 (Mettl21c downstream effector) into valosin-containing protein (VCP). Increased VCP promoted autophagic turnover of cellular components, ATP production, and cell differentiation. Knock-down of Metthl21c dismissed improvements mentioned above. Collectively, betaine could enhance aged skeletal muscle autophagy level via Mettl21c/p97/VCP axis to delay muscle loss.

Identifying Acss1, Mtfp1 and Oxct1 as key regulators and promising biomarkers of sarcopenia in various models

Mitochondrial dysfunction plays a critical role in muscular homeostasis, but the molecular mechanism underlying mitochondrial dynamics and sarcopenia awaits to be uncovered. We all know that malnutrition, cachexia, and type 2 diabetes are significant contributors to the development of sarcopenia.Therefore, we analyzed a bioinformatic analysis on cathectic differentially expressed genes (cDEGs), fasted differentially genes (fDEGs) and mitochondria-related genes. The overlapping genes identified were then validated by RT-qPCR and Western blotting experiments in various sarcopenia mice models and used to predict aging-related muscle loss in humans. First, the correlation analysis and PPI network indicated 6 overlapping candidates (Bdh1, Gdap1, Acss1, Mtfp1, Idh2, Oxct1) may constitute a regulatory effect in mitochondrial dynamics and muscle wasting. Next, we successfully established fasted, Lewis lung carcinoma (LLC) and Diabetes Mellitus (DM) induced sarcopenia mice models and verified that Acss1, Mtfp1 and Oxct1 shared common and significant variation tendency in these sarcopenia mice models. Further-more, Pearson correlation analysis showed that Acss1 was negatively related to the weight of gastrocnemius while Mtfp1 and Oxct1 displayed a significantly positive correlation with gastrocnemius weight in sarcopenic mice model induced by LLC, fasting and DM. What's more, ROC analysis based on human aging-related datasets indicated Acss1, Mtfp1, Oxct1 had outstanding diagnostic capabilities for sarcopenia. In general, we identified three hub genes (Acss1, Mtfp1 and Oxct1) that are strongly associated with mitochondrial dysfunction in sarcopenia and may provide novel and reliable indicators for screening, diagnosis, and prognosis, as well as potential therapeutic targets for patients with sarcopenia.

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.

A leaky gut contributes to reduced sarcopenia-related quality of life (SarQoL) in geriatric older adults

PURPOSE

The sarcopenia quality-of-life (SarQoL) questionnaire is designed to evaluate the quality of life of sarcopenic patients. A pathological increase in intestinal permeability leads to several systemic diseases, but its contribution to SarQoL is unknown.

METHODS

We recruited controls (n = 84, age = 74.6 ± 4.9 years) and sarcopenic (n = 55, age = 76.1 ± 4.2 years) men for validating and adapting a Pashto version of SarQoL. We measured the scores for seven domains of SarQoL, body composition, and handgrip strength (HGS). We also measured plasma zonulin as a marker of increased intestinal permeability.

RESULTS

The Pashto SarQoL exhibited adequate discriminative ability, construct validity, internal consistency, and test-retest reliability, without exhibiting the floor and ceiling effect. Sarcopenic patients had higher plasma zonulin and lower scores on SarQoL domains for physical and mental health, locomotion, body composition, functionality, activities of daily living, leisure, and fear, and cumulative SarQoL scores than controls. Plasma zonulin exhibited significant coefficients of determination with Pashto SarQoL domains for locomotion (r2 = 0.217), functionality (r2 = 0.101), activities of daily living (r2 = 0.302), and cumulative SarQoL scores (r2 = 0.168). We also found high efficacies of zonulin in diagnosing low scores for functionality (AUC = 0.785, 95% C.I = 0.708-0.863), activities of daily living (AUC = 0.785, 95% C.I = 0.708-0.863), and cumulative SarQoL scores (AUC = 0.821, 95% C.I = 0.751-0.891).

CONCLUSION

Altogether, SarQoL appears reliable in measuring the quality of life in sarcopenic patients. A leaky gut has a potential contribution to reduced SarQoL in sarcopenia.

sEMG-based Sarcopenia risk classification using empirical mode decomposition and machine learning algorithms

Early detection of the risk of sarcopenia at younger ages is crucial for implementing preventive strategies, fostering healthy muscle development, and minimizing the negative impact of sarcopenia on health and aging. In this study, we propose a novel sarcopenia risk detection technique that combines surface electromyography (sEMG) signals and empirical mode decomposition (EMD) with machine learning algorithms. First, we recorded and preprocessed sEMG data from both healthy and at-risk individuals during various physical activities, including normal walking, fast walking, performing a standard squat, and performing a wide squat. Next, electromyography (EMG) features were extracted from a normalized EMG and its intrinsic mode functions (IMFs) were obtained through EMD. Subsequently, a minimum redundancy maximum relevance (mRMR) feature selection method was employed to identify the most influential subset of features. Finally, the performances of state-of-the-art machine learning (ML) classifiers were evaluated using a leave-one-subject-out cross-validation technique, and the effectiveness of the classifiers for sarcopenia risk classification was assessed through various performance metrics. The proposed method shows a high accuracy, with accuracy rates of 0.88 for normal walking, 0.89 for fast walking, 0.81 for a standard squat, and 0.80 for a wide squat, providing reliable identification of sarcopenia risk during physical activities. Beyond early sarcopenia risk detection, this sEMG-EMD-ML system offers practical values for assessing muscle function, muscle health monitoring, and managing muscle quality for an improved daily life and well-being.

Correlation between sarcopenia and esophageal cancer: a narrative review

BACKGROUND

In recent years, the research on the relationship between sarcopenia before and after the treatment of esophageal cancer, as well as its impact on prognosis of esophageal cancer, has increased rapidly, which has aroused people's attention to the disease of patients with esophageal cancer complicated with sarcopenia. This review examines the prevalence of sarcopenia in patients with esophageal cancer, as well as the relationship between sarcopenia (before and after surgery or chemotherapy) and prognosis in patients with esophageal cancer. Moreover, we summarized the potential pathogenesis of sarcopenia and pharmacologic and non-pharmacologic therapies.

METHODS

A narrative review was performed in PubMed and Web of Science using the keywords ("esophageal cancer" or "esophageal neoplasm" or "neoplasm, esophageal" or "esophagus neoplasm" or "esophagus neoplasms" or "neoplasm, esophagus" or "neoplasms, esophagus" or "neoplasms, esophageal" or "cancer of esophagus" or "cancer of the esophagus" or "esophagus cancer" or "cancer, esophagus" or "cancers, esophagus" or "esophagus cancers" or "esophageal cancer" or "cancer, esophageal" or "cancers, esophageal" or "esophageal cancers") and ("sarcopenia" or "muscular atrophy" or "aging" or "senescence" or "biological aging" or "aging, biological" or "atrophies, muscular" or "atrophy, muscular" or "muscular atrophies" or "atrophy, muscle" or "atrophies, muscle" or "muscle atrophies"). Studies reporting relationship between sarcopenia and esophageal cancer were analyzed.

RESULTS

The results of the review suggest that the average prevalence of sarcopenia in esophageal cancer was 46.3% ± 19.6% ranging from 14.4 to 81% and sarcopenia can be an important predictor of poor prognosis in patients with esophageal cancer. Patients with esophageal cancer can suffer from sarcopenia due to their nutritional deficiencies, reduced physical activity, chemotherapy, and the effects of certain inflammatory factors and pathways. When classic diagnostic values for sarcopenia such as skeletal muscle index (SMI) are not available clinically, it is also feasible to predict esophageal cancer prognosis using simpler metrics, such as calf circumference (CC), five-count sit-up test (5-CST), and six-minute walk distance (6MWD).

CONCLUSIONS

Identifying the potential mechanism of sarcopenia in patients with esophageal cancer and implementing appropriate interventions may hold the key to improving the prognosis of these patients.

The critically ill older patient with sepsis: a narrative review

Sepsis is a significant public health concern, particularly affecting individuals above 70 years in developed countries. This is a crucial fact due to the increasing aging population, their heightened vulnerability to sepsis, and the associated high mortality rates. However, the morbidity and long-term outcomes are even more notable. While many patients respond well to timely and appropriate interventions, it is imperative to enhance efforts in identifying, documenting, preventing, and treating sepsis. Managing sepsis in older patients poses greater challenges and necessitates a comprehensive understanding of predisposing factors and a heightened suspicion for diagnosing infections and assessing the risk of sudden deterioration into sepsis. Despite age often being considered an independent risk factor for mortality and morbidity, recent research emphasizes the pivotal roles of frailty, disease severity, and comorbid conditions in influencing health outcomes. In addition, it is important to inquire about the patient's preferences and establish a personalized treatment plan that considers their potential for recovery with quality of life and functional outcomes. This review provides a summary of the most crucial aspects to consider when dealing with an old critically ill patient with sepsis.

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

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

Ashwagandha Ethanol Extract Attenuates Sarcopenia-Related Muscle Atrophy in Aged Mice

The investigation focused on the impact of Withania somnifera (ashwagandha) extract (WSE) on age-related mechanisms affecting skeletal muscle sarcopenia-related muscle atrophy in aged mice. Beyond evaluating muscular aspects, the study explored chronic low-grade inflammation, muscle regeneration, and mitochondrial biogenesis. WSE administration, in comparison to the control group, demonstrated no significant differences in body weight, diet, or water intake, affirming its safety profile. Notably, WSE exhibited a propensity to reduce epidermal and abdominal fat while significantly increasing muscle mass at a dosage of 200 mg/kg. The muscle-to-fat ratio, adjusted for body weight, increased across all treatment groups. WSE administration led to a reduction in the pro-inflammatory cytokines TNF-α and IL-1β, mitigating inflammation-associated muscle atrophy. In a 12-month-old mouse model equivalent to a 50-year-old human, WSE effectively preserved muscle strength, stabilized grip strength, and increased muscle tissue weight. Positive effects were observed in running performance and endurance. Mechanistically, WSE balanced muscle protein synthesis/degradation, promoted fiber differentiation, and enhanced mitochondrial biogenesis through the IGF-1/Akt/mTOR pathway. This study provides compelling evidence for the anti-sarcopenic effects of WSE, positioning it as a promising candidate for preventing sarcopenia pending further clinical validation.

Association between serum copper levels and muscle mass: results from NHANES 2011-2016

Copper is essential for various biological processes. However, excess copper has several adverse health effects. The effects of serum copper on muscle mass are poorly understood. This study aimed to investigate the association between serum copper levels and muscle mass in the US population. We utilized National Health and Nutrition Examination Survey (NHANES) data between 2011 and 2016 for analysis. Data on serum copper, muscle mass (measured using the appendicular skeletal muscle mass index (ASMI)), and covariates were extracted and analyzed. Weighted multivariate linear regression analyses and smooth curve fittings were performed to investigate the association between serum copper levels and ASMI. Subgroup analyses stratified according to age and sex were performed. In the presence of nonlinearity, threshold effect analysis was performed using a two-piecewise linear regression model. A total of 3860 participants were included in the final analysis. Serum copper levels were negatively associated with ASMI in the fully adjusted model. Furthermore, by comparing participants in the highest and lowest tertiles of serum copper levels, we found that the ASMI decreased by 0.292 kg/m2. In the sex-stratified subgroup analysis, we observed an inverse association between serum copper levels and the ASMI in both men and women. When stratified by age, the association remained significant among participants < 40 years of age, but not among those ≥ 40 years old. Smooth curve fitting revealed a nonlinear relationship between serum copper and ASMI, with an inflection point identified at 150.6 μg/dL. Our study revealed an inverse relationship between serum copper levels and muscle mass. This finding improves the current knowledge on the impact of serum copper on muscle loss and highlights the importance of serum copper homeostasis in muscle health.

[Physical rehabilitation in sarcopenia: modern approaches. (A literature review)]

The number of middle-aged and elderly population is increasing every year. At the same time, the course of most chronic diseases worsens with age, which can be explained by significant changes in body composition, including redistribution and increase of fat mass and decrease in muscle and skeletal mass. Thus, a decrease in muscle mass becomes intrinsic for the body from the age of 40 and develops on average by 0.5-1.0% per year. The prevalence of patients with sarcopenia is estimated to be between 11 and 50% in different age groups of population: middle, elderly and senile. In addition, the decline in physical activity associated with the urbanization and automation of labor exacerbates the disease at a younger age, which predicts an increase in the number of such patients in the future.

OBJECTIVE

To determine the role of physical rehabilitation in sarcopenia.

MATERIAL AND METHODS

A systematic review including studies found in PubMed, MedLine, Scopus and Web of Science Core Collections databases for 2019-2022 was conducted. The used enrollment criteria were the following: systematic reviews, including cross-over or cohort studies targeting at persons aged from 40 to 90 years of both sexes, with available data on sarcopenia, its severe form or other combinations of physical performance markers called sarcopenia. The mandatory parameter for inclusion in the study was the presence of the effectiveness assessment of physical rehabilitation without limiting its parameters. The systematic review was performed in accordance with the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020.

RESULTS

The best kind of training are 30-60-minute comprehensive methods with predominance of resistance exercises with minimum duration of the course of 3 months and frequency of 3 inconsistent in-person trainings per week under the supervision of a specialist for patients with sarcopenia in order to increase muscle strength and mass, as well as performance. The intensity should consist of the following parameters: start with fewer sets but more repetitions (12-15) with less intensity (55% of maximum) and move to more sets with less repetition (4-6) and greater intensity (>80% of maximum).

CONCLUSION

This article describes the parameters of exercises that are most effective in terms of muscle strength and mass increase and safe for patients. The compilation and further study of this complex in practice are needed.

From Chronodisruption to Sarcopenia: The Therapeutic Potential of Melatonin

Sarcopenia is an age-related condition that involves a progressive decline in muscle mass and function, leading to increased risk of falls, frailty, and mortality. Although the exact mechanisms are not fully understood, aging-related processes like inflammation, oxidative stress, reduced mitochondrial capacity, and cell apoptosis contribute to this decline. Disruption of the circadian system with age may initiate these pathways in skeletal muscle, preceding the onset of sarcopenia. At present, there is no pharmacological treatment for sarcopenia, only resistance exercise and proper nutrition may delay its onset. Melatonin, derived from tryptophan, emerges as an exceptional candidate for treating sarcopenia due to its chronobiotic, antioxidant, and anti-inflammatory properties. Its impact on mitochondria and organelle, where it is synthesized and crucial in aging skeletal muscle, further highlights its potential. In this review, we discuss the influence of clock genes in muscular aging, with special reference to peripheral clock genes in the skeletal muscle, as well as their relationship with melatonin, which is proposed as a potential therapy against sarcopenia.

Astragulus embranaceus (Fisch.) Bge-Dioscorea opposita Thunb herb pair ameliorates sarcopenia in senile type 2 diabetes mellitus through Rab5a/mTOR-mediated mitochondrial dysfunction

ETHNOPHARMACOLOGICAL RELEVANCE

The combination of Astragulus embranaceus (Fisch.) Bge (Huangqi) and Dioscorea opposita Thunb (Shanyao) are one of the most widely accepted herb pairs in traditional Chinese medicine prescriptions for treating sarcopenia. However, the mechanisms underlying the combination of these herbs for anti-sarcopenia treatment are not yet fully understood.

AIM OF THE STUDY

To investigate the potential effect of the Astragulus embranaceus (Fisch.) Bge and Dioscorea opposita Thunb herb pair (Ast-Dio) on sarcopenia in mice that have been induced with senile type 2 diabetes mellitus, as well as to explore the underlying mechanisms related to the Rab5a/mTOR signaling pathway and mitochondrial quality control.

MATERIALS AND METHODS

Network pharmacology was utilized to identify the main active ingredients of Ast-Dio and potential therapeutic targets for sarcopenia. Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted to explore the underlying mechanisms of Ast-Dio in treating sarcopenia. The high-performance liquid chromatography method coupled with triple-quadrupole tandem mass spectrometry was developed to quantify the major constituents of Ast-Dio. Male C57/BL6 mice, aged 12 months, induced with type 2 diabetes mellitus via streptozotocin were divided into three groups for 8 weeks: the model group, Ast-Dio treatment group (7.8 g/kg), and metformin treatment group (100 mg/kg). Normal control groups included mice aged 3 and 12 months, respectively. The study monitored changes in fasting blood glucose levels, grip strength, and body weight during 8 weeks of intragastric administration. Liver and kidney function in mice was evaluated by measuring the levels of serum creatinine, alanine transaminase, and aspartate transaminase. Skeletal muscle mass condition was evaluated by muscle weight, and hematoxylin and eosin staining. Protein and mRNA expressions related to muscle atrophy, mitochondrial quality control, and the Rab5a/mTOR signaling pathway were detected using immunofluorescence staining, immunohistochemical staining, Western blotting, and quantitative real-time polymerase chain reaction. In addition, transmission electron microscopy was employed to investigate the condition of mitochondria in the groups.

RESULTS

Through the prediction analysis of network pharmacology, we identified mTOR as one of the primary targets for Ast-Dio therapy of sarcopenia. Gene Ontology functional enrichment analysis revealed that mitochondrial control quality is crucial in the treatment of sarcopenia with Ast-Dio. Our findings showed that senile type 2 diabetes mellitus induced muscle mass loss and a reduction in grip strength, both of which were dramatically restored by Ast-Dio treatment. Notably, Ast-Dio increased Myogenin expression while decreasing Atrogin-1 and MuRF-1 expression. Additionally, Ast-Dio activated Rab5a/mTOR and its downstream effector AMPK. Moreover, Ast-Dio modulated mitochondrial quality control by decreasing Mitofusin-2 expression while increasing the expression of TFAM, PGC-1α, and MFF.

CONCLUSIONS

Our results suggest that Ast-Dio treatment may alleviate sarcopenia in mice with senile type 2 diabetes mellitus through its effects on the Rab5a/mTOR pathway and mitochondrial quality control.

Sarcopenia and myosteatosis diagnostic tool for gastrointestinal cancer: creatinine to cystatin C ratio as evaluation marker

OBJECTIVE

This study aimed to develop a simplified diagnostic tool for assessing sarcopenia and myosteatosis in gastrointestinal cancer patients, focusing on the creatinine to cystatin C ratio (CCR) as an evaluation marker.

METHODS

955 patients were split into training (n = 671) and validation (n = 284) cohorts. Using logistic regression, risk factors for sarcopenia and myosteatosis were identified. The predictive capacity of the developed model was examined. The association between CCR and muscle imaging parameters, along with its impact on clinical outcomes, was analyzed.

RESULTS

No significant differences were observed in baseline traits between cohorts. CCR emerged as a significant risk factor for both sarcopenia and myosteatosis. Nomograms for diagnosing these conditions demonstrated strong predictive ability, with AUC values indicating high accuracy (sarcopenia AUC: 0.865-0.872; myosteatosis AUC: 0.848-0.849). The clinical utility of the nomograms was confirmed through decision curve analysis. CCR showed significant association with muscle imaging parameters and was a reliable indicator for assessing the risk of sarcopenia, myosteatosis, and cachexia. Moreover, CCR was able to differentiate between patient survival and disease progression rates.

CONCLUSION

A diagnostic tool for sarcopenia and myosteatosis in gastrointestinal cancer patients was developed, with CCR being a pivotal biomarker for disease diagnosis and prognosis prediction.

The relationship between sarcopenia and serum irisin and TNF-α levels in newly diagnosed cancer patients

OBJECTIVE

Sarcopenia in patients with cancer makes patients physically weak and adversely affects their compliance with treatment. In this study, we investigated the relationship between sarcopenia in patients with cancer and circulating irisin and tumor necrosis factor-alpha (TNF-α) levels.

MATERIAL AND METHOD

A total of 141 patients with different types of newly diagnosed cancer were divided into two groups, sarcopenia (n = 72) and non-sarcopenia (n = 69) groups. The body compositions of the patients were measured using bioelectrical impedance (BIA) and muscle strength using hand grip strength (HGS) tests. Serum irisin and TNF-α levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

In our study, serum irisin levels were found to be significantly lower (p < 0.01) and TNF-α levels were found to be significantly higher (p = 0.014) in the sarcopenia group. Skeletal muscle index (SMI) and HGS values and serum irisin levels were positively correlated [(r: 0.451, p < 0.001), (r: 0.469, p < 0.001)], and SMI and HGS values and serum TNF-α levels were negatively correlated [(r: -0.181, p = 0.032) and (r: -0.143, p = 0.090), respectively]. In addition, multiple linear regression analysis showed that serum irisin and TNF-α levels were independent predictors of sarcopenia.

CONCLUSION

Serum irisin levels were found to be significantly lower in patients with cancer with sarcopenia, and TNF-α levels were found to be significantly higher. These two markers can be used as potential biomarkers for the diagnosis of sarcopenia in patients with cancer. The efficacy and possible mechanisms of action of irisin and TNF-α in the diagnosis of sarcopenia should be investigated with larger patient groups.

The Effects of Flavonoids on Skeletal Muscle Mass, Muscle Function, and Physical Performance in Individuals with Sarcopenia: A Systematic Review of Randomized Controlled Trials

Sarcopenia has become a significant obstacle to healthy aging in older adults. Flavonoids may contribute to treating sarcopenia, and attenuate the age-related loss of skeletal muscle mass, muscle strength, and physical function, however, their benefits in sarcopenic individuals remain unclear. This systematic review aimed to evaluate the effect of flavonoids on muscle mass, muscle strength, and physical performance in adults with sarcopenia based on randomized controlled trials (RCTs). This review was conducted in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the risk of bias was assessed using the Cochrane risk of bias tool. The article search was conducted using PubMed, Scopus, Embase, Cochrane, Web of Science databases, and Google Scholar for the period until June 2023. RCTs that assessed the effects of flavonoids/flavonoids combined with other supplementation/flavonoid-rich supplementations on skeletal muscle mass, muscle strength, and physical performance in adults diagnosed with sarcopenia before intervention were included. From the 309 articles found, a total of 6 RCTs met the inclusion criteria. RCTs evaluated the main outcomes of tea catechins, epicatechin, and isoflavones intervention. Skeletal muscle mass significantly increased in three studies, muscle strength significantly elevated in two studies, and physical performance significantly improved in two studies. The majority of studies (five in six) found at least one of the main outcomes is elevated by flavonoids intervention. Flavonoids may have a great potential to treat sarcopenia.

Spontaneous pulmonary herniation in post-polio syndrome

Pulmonary hernias are typically a result of trauma, thoracic operations, or congenital defects. Spontaneous lung hernias without a prior overt injury are notably rare. The presence of spontaneous lung hernias has not been reported in post-polio syndrome. Post-polio syndrome is a late sequela of poliomyelitis that usually presents 30-40 years after the initial illness with new presentations of progressive muscle weakness, abnormal muscle fatigue, muscle atrophy, and myalgia. This case report describes the presentation and imaging of a post-polio patient with an atraumatic, spontaneous lung hernia. A discussion on pulmonary hernias, diagnostic imaging, and management is also included.

Ginsenoside Rc, an Active Component of Panax ginseng, Alleviates Oxidative Stress-Induced Muscle Atrophy via Improvement of Mitochondrial Biogenesis

Loss of skeletal muscle mass and function has detrimental effects on quality of life, morbidity, and mortality, and is particularly relevant in aging societies. The enhancement of mitochondrial function has shown promise in promoting muscle differentiation and function. Ginsenoside Rc (gRc), a major component of ginseng, has various pharmacological activities; however, its effect on muscle loss remains poorly explored. In this study, we examined the effects of gRc on the hydrogen peroxide (H2O2)-induced reduction of cell viability in C2C12 myoblasts and myotubes and H2O2-induced myotube degradation. In addition, we investigated the effects of gRc on the production of intracellular reactive oxygen species (ROS) and mitochondrial superoxide, ATP generation, and peroxisome proliferator-activated receptor-gamma co-activator 1α (PGC-1α) activity in myoblasts and myotubes under H2O2 treatment. Furthermore, to elucidate the mechanism of action of gRc, we conducted a transcriptome analysis of myotubes treated with or without gRc under H2O2 treatment. gRc effectively suppressed H2O2-induced cytotoxicity, intracellular ROS, and mitochondrial superoxide production, restored PGC-1α promoter activity, and increased ATP synthesis. Moreover, gRc significantly affected the expression levels of genes involved in maintaining mitochondrial mass and biogenesis, while downregulating genes associated with muscle degradation in C2C12 myotubes under oxidative stress. We provide compelling evidence supporting the potential of gRc as a promising treatment for muscle loss and weakness. Further investigations of the pharmacological effects of gRc under various pathological conditions of muscle loss will contribute to the clinical development of gRc as a therapeutic intervention.

Muscle-Brain crosstalk in cognitive impairment

Sarcopenia is an age-related, involuntary loss of skeletal muscle mass and strength. Alzheimer's disease (AD) is the most common cause of dementia in elderly adults. To date, no effective cures for sarcopenia and AD are available. Physical and cognitive impairments are two major causes of disability in the elderly population, which severely decrease their quality of life and increase their economic burden. Clinically, sarcopenia is strongly associated with AD. However, the underlying factors for this association remain unknown. Mechanistic studies on muscle-brain crosstalk during cognitive impairment might shed light on new insights and novel therapeutic approaches for combating cognitive decline and AD. In this review, we summarize the latest studies emphasizing the association between sarcopenia and cognitive impairment. The underlying mechanisms involved in muscle-brain crosstalk and the potential implications of such crosstalk are discussed. Finally, future directions for drug development to improve age-related cognitive impairment and AD-related cognitive dysfunction are also explored.

Association between dietary inflammatory index and low muscle mass in diabetes/prediabetes patients

BACKGROUND

Growing evidence has increasingly validated that individuals with diabetes/prediabetes have a higher prevalence of low skeletal muscle mass and function compared to healthy individuals. The anti-inflammatory diet is considered a promising and modifiable approach to optimize skeletal muscle quality. However, current evidence on the relation of dietary inflammatory potential with low muscle mass among diabetic/prediabetic patients is limited.

METHODS

Dietary consumption was determined by trained staff using the 24-hour diet recall method, and the Dietary Inflammatory Index (DII) was scored based on a previously validated approach that included 26 food parameters. Dual-energy X-ray absorptiometry was used to assess the mass of skeletal muscle and low muscle mass was defined based on the sarcopenia index. Logistic regression was conducted to calculate odds ratios (ORs) and 95 % confidence intervals (CIs). Restricted cubic spline (RCS) analysis was also performed to visually represent the relationship between DII and low muscle mass. Furthermore, sensitivity and subgroup analyses were conducted.

RESULTS

In this study, a total of 4269 eligible participants were registered, comprising 1975 (46.26 %) females and 2294 (53.74 %) males. The mean age was 49.98 ± 0.31 years old, and the mean DII score was 1.53 ± 0.04. Among them, 934 (21.88 %) patients were defined as having low muscle mass, while 3335 (78.12 %) were without low muscle mass. The highest tertile (T3) of DII had an 61 % increased risk of low muscle mass (OR = 1.61, 95%CI: 1.19-2.17, p for trend = 0.004) compared to the lowest tertile. The RCS curve displayed a linear dose-response relationship between DII score and low muscle mass risk in patients with diabetes/prediabetes. Subgroup and sensitivity analyses provided robustness to our results.

CONCLUSIONS

Our results indicated that a higher DII score was associated with an increased risk of low muscle mass among diabetes/prediabetes patients. These findings provided a nutritional strategy for diabetes/prediabetes patients to prevent skeletal muscle mass loss.

Dietary diversity and possible sarcopenia among older people in China: a nationwide population-based study

Background

Sarcopenia is a common geriatric disease. Many dietary factors may contribute to the development of sarcopenia. Few studies have been conducted on dietary diversity and sarcopenia in Chinese older adults. Among a nationwide sample, the objective of this study is to assess the association between the dietary diversity score (DDS) and the prevalence of possible sarcopenia. We considered the different patterns of dietary diversity in relation to possible sarcopenia.

Methods

We conducted this analysis utilizing the cross-sectional data from the 2012, 2014, and 2018 waves of the Chinese longitudinal healthy longevity survey (CLHLS). A standard developed by the Asian Working Group for Sarcopenia 2019 (AWGS2019) was used to assess the possibility of sarcopenia. On the basis of the DDS generated by previous studies, we have constructed four new indicators as follows: total diet, animal-based diet, plant-based diet, and plant-based diet without the consumption of legume products and nuts. We used the generalized estimation equation (GEE) model to evaluate the associations between the DDS of the total diet, animal-based diet, plant-based diet, and plant-based diet without the intake of legume products and nuts and possible sarcopenia. These associations were statistically adjusted for a variety of potential confounders. Sensitivity analysis was performed by excluding some participants who were long-term bedridden, had Alzheimer's disease, or were terminally ill.

Results

The analysis included 6,624 participants (mean age 83.4 years at baseline). In our study, we found that participants with a higher DDS of the total diet (OR = 0.62; 95% CI: 0.51-0.77), animal-based diet (OR = 0.62; 95% CI: 0.49-0.79), and plant-based diet (OR = 0.64;95% CI: 0.51-0.80) were at a lower risk of developing sarcopenia. In sensitivity analyses, the associations remained unchanged.

Conclusion

Taking a diversified diet, including animal foods, may reduce the risk of developing sarcopenia. According to the findings of this study, adopting a diversified diet might reduce the risk of sarcopenia for older adults.

Pathogenesis, Intervention, and Current Status of Drug Development for Sarcopenia: A Review

Sarcopenia refers to the loss of muscle strength and mass in older individuals and is a major determinant of fall risk and impaired ability to perform activities of daily living, often leading to disability, loss of independence, and death. Owing to its impact on morbidity, mortality, and healthcare expenditure, sarcopenia in the elderly has become a major focus of research and public policy debates worldwide. Despite its clinical importance, sarcopenia remains under-recognized and poorly managed in routine clinical practice, partly owing to the lack of available diagnostic testing and uniform diagnostic criteria. Since the World Health Organization and the United States assigned a disease code for sarcopenia in 2016, countries worldwide have assigned their own disease codes for sarcopenia. However, there are currently no approved pharmacological agents for the treatment of sarcopenia; therefore, interventions for sarcopenia primarily focus on physical therapy for muscle strengthening and gait training as well as adequate protein intake. In this review, we aimed to examine the latest information on the epidemiology, molecular mechanisms, interventions, and possible treatments with new drugs for sarcopenia.

Sarcopenia and Sarcopenic Obesity and Osteoarthritis: A Discussion among Muscles, Fat, Bones, and Aging

Aging is a physical procedure for people and nature. Our aging world is expanding because of the life span extension. Aging has a crucial relationship with our body composition (muscles, bones, and adipose tissue), which is characterized by an increase in fat mass and a gradual decrease in muscle mass and strength and bone density. These alterations affect physical performance and impact quality of life enhancing the risk for non-communicable diseases, immobilization, and disability. As far we know, osteoarthritis of lower limbs, sarcopenic obesity, and muscle mass and/or strength loss are treated separately. However, bones, muscles, adipose tissue, and aging appear to have an interconnection through a dialogue as they talk to each other. Health disorders are coming into the surface when this relationship is disrupted. The aim of our study is to search deeper into this interconnection, so that when adipose tissue increases, we have to take a look into the condition of muscle mass, bone, and connective tissue and vice versa, through the assessment of physical performance. Consequently, the triad muscle-bone-adipose tissue disorders by aging should be treated as a single entity.

Identification of the cuproptosis-related hub genes and therapeutic agents for sarcopenia

Background: Along with acceleration of population aging, the increasing prevalence of sarcopenia has posed a heavy burden on families as well as society. In this context, it is of great significance to diagnose and intervene sarcopenia as early as possible. Recent evidence has indicated the role of cuproptosis in the development of sarcopenia. In this study, we aimed to seek the key cuproptosis-related genes that can be used for identification and intervention of sarcopenia.

Methods: The GSE111016 dataset was retrieved from GEO. The 31 cuproptosis-related genes (CRGs) were obtained from previous published studies. The differentially expressed genes (DEGs) and Weighed gene co-expression network analysis (WGCNA) were subsequently analyzed. The core hub genes were acquired by the intersection of DEGs, WGCNA and CRGs. Through logistic regression analysis, we established a diagnostic model of sarcopenia based on the selected biomarkers and was validated in muscle samples from GSE111006 and GSE167186. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis were performed on these genes. Furthermore, the gene set enrichment analysis (GSEA), and immune cell infiltration were also conducted on the identified core genes. Finally, we screened the potential drugs targeting the potential biomarkers of sarcopenia.

Results: A total of 902 DEGs and WGCNA containing 1,281 significant genes were preliminarily selected. Intersection of DEGs, WGCNA and CRGs yielded four core genes (PDHA1, DLAT, PDHB, and NDUFC1) as potential biomarkers for the prediction of sarcopenia. The predictive model was established and validated with high AUC values. KEGG pathway and Gene Ontology biological analysis indicated these core genes may play a crucial role in energy metabolism in mitochondria, oxidation process, and aging-related degenerative diseases. In addition, the immune cells may be involved in the development of sarcopenia through mitochondrial metabolism. Finally, metformin was identified as a promising strategy of sarcopenia treatment via targeting NDUFC1.

Conclusion: The four cuproptosis-related genes PDHA1, DLAT, PDHB and NDUFC1 may be the diagnostic biomarkers for sarcopenia, and metformin holds great potential to be developed as a therapy for sarcopenia. These outcomes provide new insights for better understanding of sarcopenia and innovative therapeutic approaches.

Increasing Skeletal Muscle Mass in Mice by Non-Invasive Intramuscular Delivery of Myostatin Inhibitory Peptide by Iontophoresis

Sarcopenia is a major public health issue that affects older adults. Myostatin inhibitory-D-peptide-35 (MID-35) can increase skeletal muscle and is a candidate therapeutic agent, but a non-invasive and accessible technology for the intramuscular delivery of MID-35 is required. Recently, we succeeded in the intradermal delivery of various macromolecules, such as siRNA and antibodies, by iontophoresis (ItP), a non-invasive transdermal drug delivery technology that uses weak electricity. Thus, we expected that ItP could deliver MID-35 non-invasively from the skin surface to skeletal muscle. In the present study, ItP was performed with a fluorescently labeled peptide on mouse hind leg skin. Fluorescent signal was observed in both skin and skeletal muscle. This result suggested that the peptide was effectively delivered to skeletal muscle from skin surface by ItP. Then, the effect of MID-35/ItP on skeletal muscle mass was evaluated. The skeletal muscle mass increased 1.25 times with ItP of MID-35. In addition, the percentage of new and mature muscle fibers tended to increase, and ItP delivery of MID-35 showed a tendency to induce alterations in the levels of mRNA of genes downstream of myostatin. In conclusion, ItP of myostatin inhibitory peptide is a potentially useful strategy for treating sarcopenia.

Sarcopenia of kidney transplant recipients as a predictive marker for reduced graft function and graft survival after kidney transplantation

PURPOSE

The association between sarcopenia of kidney transplant recipients and outcome after kidney transplantation (KT) has not yet been fully understood and is still considered controversial. The aim of our study was to analyze the impact of pre-transplant sarcopenia on graft function, postoperative complication rates, and survival of the patients after renal transplantation.

METHODS

In this retrospective single-center study, all patients who underwent KT (01/2013-12/2017) were included. Demographic data, rejection rates, delayed graft function, and graft and patient survival rates were analyzed. Sarcopenia was measured in computed tomography images by the sex-adjusted Hounsfield unit average calculation (HUAC).

RESULTS

During the study period, 111 single KTs (38 women and 73 men) were performed. Living donor kidney transplants were performed in 48.6%. In total, 32.4% patients had sarcopenia. Sarcopenic patients were significantly older (59.6 years vs. 49.8 years; p < 0.001), had a higher body mass index (BMI = 27.6 kg/m2 vs. 25.0 kg/m2; p = 0.002), and were more likely to receive deceased donor kidneys (72.2% vs. 41.3%; p = 0.002). Interestingly, 3 years after KT, the creatinine serum levels were significantly higher (2.0 mg/dl vs. 1.5 mg/dl; p = 0.001), whereas eGFR (39.9 ml/min vs. 53.4 ml/min; p = 0.001) and graft survival were significantly lower (p = 0.004) in sarcopenic transplant recipients. Sarcopenic patients stayed in hospital significantly longer postoperatively than those who were non-sarcopenic.

CONCLUSIONS

At the time of kidney transplantation, sarcopenia was found to predict reduced long-term graft function and diminished graft survival after KT. The early identification of sarcopenic patients can not only enable an optimized selection of recipients, but also the initiation of pre-habilitation programs during the waiting period.

Fiber-Type Shifting in Sarcopenia of Old Age: Proteomic Profiling of the Contractile Apparatus of Skeletal Muscles

The progressive loss of skeletal muscle mass and concomitant reduction in contractile strength plays a central role in frailty syndrome. Age-related neuronal impairments are closely associated with sarcopenia in the elderly, which is characterized by severe muscular atrophy that can considerably lessen the overall quality of life at old age. Mass-spectrometry-based proteomic surveys of senescent human skeletal muscles, as well as animal models of sarcopenia, have decisively improved our understanding of the molecular and cellular consequences of muscular atrophy and associated fiber-type shifting during aging. This review outlines the mass spectrometric identification of proteome-wide changes in atrophying skeletal muscles, with a focus on contractile proteins as potential markers of changes in fiber-type distribution patterns. The observed trend of fast-to-slow transitions in individual human skeletal muscles during the aging process is most likely linked to a preferential susceptibility of fast-twitching muscle fibers to muscular atrophy. Studies with senescent animal models, including mostly aged rodent skeletal muscles, have confirmed fiber-type shifting. The proteomic analysis of fast versus slow isoforms of key contractile proteins, such as myosin heavy chains, myosin light chains, actins, troponins and tropomyosins, suggests them as suitable bioanalytical tools of fiber-type transitions during aging.

Insights into Pathogenesis, Nutritional and Drug Approach in Sarcopenia: A Systematic Review

Sarcopenia is a multifactorial condition related to the loss of muscle mass and strength due to aging, eating habits, physical inactivity, or even caused by another disease. Affected individuals have a higher risk of falls and may be associated with heart disease, respiratory diseases, cognitive impairment, and consequently an increased risk of hospitalization, in addition to causing an economic impact due to the high cost of care during the stay in hospitals. The standardization of appropriate treatment for patients with sarcopenia that could help reduce pathology-related morbidity is necessary. For these reasons, this study aimed to perform a systematic review of the role of nutrition and drugs that could ameliorate the health and quality of life of sarcopenic patients and PRISMA guidelines were followed. Lifestyle interventions have shown a profound impact on sarcopenia treatment but using supplements and different drugs can also impact skeletal muscle maintenance. Creatine, leucine, branched-chain amino acids, omega 3, and vitamin D can show benefits. Although with controversial results, medications such as Metformin, GLP-1, losartan, statin, growth hormone, and dipeptidyl peptidase 4 inhibitors have also been considered and can alter the sarcopenic's metabolic parameters, protect against cardiovascular diseases and outcomes, while protecting muscles.

Two-CyDye-Based 2D-DIGE Analysis of Aged Human Muscle Biopsy Specimens

The gradual loss of skeletal muscle mass during aging and associated decline in contractile strength can result in reduced fitness, frailty, and loss of independence. In order to better understand the molecular and cellular mechanisms that underlie sarcopenia of old age and the frailty syndrome, as well as identify novel therapeutic targets to treat age-related fiber wasting, it is crucial to develop a comprehensive biomarker signature of muscle aging. Fluorescence two-dimensional gel electrophoresis (2D-DIGE) in combination with sensitive mass spectrometry presents an ideal bioanalytical tool for biomarker discovery in biogerontology. This chapter outlines the application of the 2D-DIGE method for the comparative analysis of human biopsy specimens from middle-aged versus senescent individuals using a two-CyDye-based method.

The Effect of Metabolites on Mitochondrial Functions in the Pathogenesis of Skeletal Muscle Aging

Sarcopenia is an age-related systemic disease characterized by skeletal muscle aging that generally severely affects the quality of life of elderly patients. Metabolomics analysis is a powerful tool for qualitatively and quantitatively characterizing the small molecule metabolomics of various biological matrices in order to clarify all key scientific problems concerning cell metabolism. The discovery of optimal therapy requires a thorough understanding of the cellular metabolic mechanism of skeletal muscle aging. In this review, the relationship between skeletal muscle mitochondria, amino acid, vitamin, lipid, adipokines, intestinal microbiota and vascular microenvironment has been separately reviewed from the perspective of metabolomics, and a new therapeutic direction has been suggested.