Sarcopenia: Molecular regulatory network for loss of muscle mass and function

Triglyceride-glucose index as a predictor of the risk of sarcopenia in elderly patients with OSA: a multicenter study

BACKGROUND

Given the clear association between obstructive sleep apnea (OSA) and metabolic disorders, coupled with a limited understanding of sarcopenia in patients with OSA, this study aimed to investigate the relationship between triglyceride-glucose (TyG) index and sarcopenia and in an elderly population with OSA.

METHODS

Multiple hematological and sleep-breathing status were meticulously recorded in the cohorts. The SARC-F scale ≥ 4 was considered indicative of probable sarcopenia. The correlations between clinical indicators and the SARC-F score were analyzed. The area under the curve (AUC) was utilized to assess the predictive ability of TyG for sarcopenia and sarcopenic obesity. Logistic regression analysis and sensitivity stratification were employed to explore the influence of TyG.

RESULTS

A total of 1,148 individuals were included, among whom the median age was 66 (62, 71). 46.3% (n = 531) were diagnosed with severe OSA, while 24.0% (n = 276) had probable sarcopenia. The SARC-F score exhibited positive correlations with TyG (r = 0.122, P < 0.01), but it was negatively correlated with mean peripheral oxygen saturation (mean SpO2, r = -0.157, P < 0.01). The AUC for assessing sarcopenia using TyG was 65.7% (95% confidence intervals (95%CI): 61.9-69.5%. Furthermore, the cutoff value for TyG was 8.855 (sensitivity = 67.4%, specificity = 62.8%). Logistic regression and stratified sensitivity analyses, adjusted for various influencing factors, collectively revealed that TyG was a risk-related predictor of probable sarcopenia (all odds ratio > 2.0, P < 0.05).

CONCLUSIONS

The TyG index emerges as an independent predictor of sarcopenia in patients with OSA, shedding light on the complex interplay between nighttime hypoxia and muscle health.

Exploration of Pathogenesis and Cutting-Edge Treatment Strategies of Sarcopenia: A Narrative Review

Sarcopenia a progressive and multifactorial musculoskeletal syndrome characterized by loss of muscle mass and function, poses a significant global health challenge, particularly in aging populations. Epidemiological studies reveal that sarcopenia affects approximately 5-10% of the general population, with prevalence rates escalating dramatically after age 60 to reach 10-27% in older adults. This age-associated increase contributes significantly to healthcare burdens by elevating risks of disability, frailty, and mortality. Despite its profound impact, current clinical approaches to sarcopenia remain limited. While resistance exercise and protein supplementation form the cornerstone of management, their efficacy is often constrained by poor long-term adherence and variable individual responses, highlighting the urgent need for more comprehensive and personalized treatment strategies. The pathogenesis of sarcopenia is complex and influenced by various factors, including aging, inflammation, nutritional deficits, physical inactivity, and mitochondrial dysfunction. However, the precise molecular mechanisms underlying this condition are still not fully understood. Recent research has made significant strides in elucidating the intricate mechanisms contributing to sarcopenia, revealing novel insights into its molecular and cellular underpinnings. Notably, emerging evidence points to the pivotal role of mitochondrial dysfunction, altered myokine profiles, and neuromuscular junction degeneration in sarcopenia progression. Additionally, breakthroughs in stem cell therapy, exosome-based treatments, and precision nutrition offer promising avenues for clinical intervention. This review aims to synthesize the latest advancements in sarcopenia research, focusing on the novel contributions to its pathogenesis and treatment strategies. We explore emerging trends such as the role of cellular senescence, epigenetic regulation, and targeted therapeutic interventions that could reshape future approaches to managing sarcopenia. By highlighting recent breakthroughs and cutting-edge research, we hope to advance the understanding of sarcopenia and foster the translation of these findings into effective clinical therapies.

Clinical significance of serum irisin, 25(OH)D3 and albumin in older adults with chronic disease and sarcopenia

BACKGROUND

Sarcopenia, characterized by progressive muscle mass and strength decline, poses a significant health challenge among older adults, especially those with chronic diseases. Our study aims to evaluate the combined diagnostic potential of irisin, 25(OH)D3, and albumin for sarcopenia in older patients with chronic conditions.

METHODS

A cohort of 393 older patients with chronic diseases, including 117 diagnosed with sarcopenia were included. Fasting blood samples were collected, and serum biomarkers (25(OH)D3, albumin, and irisin) were measured using automated biochemical analyzers and enzyme-linked immunosorbent assay to evaluate nutritional and muscle-related parameters.

RESULTS

The prevalence of sarcopenia was higher among patients aged 80 or older compared to younger age groups in our study population. Strong associations were observed between sarcopenia and osteoporosis, tumors, and risk of malnutrition. Serum irisin, 25(OH)D3, and albumin levels were significantly lower in sarcopenic patients. Individual biomarkers displayed diagnostic potential, and a combined biomarker test showed superior accuracy. Multivariate logistic regression identified age, osteoporosis, malnutrition, and fatigue as independent risk factors, while higher serum biomarker levels correlated with reduced sarcopenia risk. Positive correlations were observed between serum biomarkers and sarcopenia severity indicators.

CONCLUSIONS

This study highlights the potential of irisin, 25(OH)D3, and albumin as diagnostic and prognostic tools for sarcopenia in older patients with chronic diseases, contributing to early detection and intervention strategies to enhance their quality of life.

Baseline (modified) Glasgow prognostic score as a predictor of therapeutic response to immune checkpoint inhibitors in solid tumors: A systematic review and meta‑analysis

A systemic analysis was performed to evaluate the prognostic utility of the Glasgow prognostic score (GPS) and the modified (m)GPS in cancer patients treated with immune checkpoint inhibitors (ICI). The PubMed, Cochrane Library, EMBASE and Google Scholar databases were searched for entries added until May 1st, 2023, to obtain relevant articles for this study. The analysis examined several clinical outcomes, including overall survival (OS), progression-free survival (PFS), objective response rate and disease control rate (DCR). In this analysis, a total of 38 articles with 3,772 patients were included. The pooled results indicated that patients with high GPS levels had shorter OS [GPS 2 vs. 0, hazard ratio (HR): 4.35, P<0.001; GPS 1 vs. 0, HR: 2.00, P<0.001; GPS 2 vs. 1/0, HR: 2.62, P<0.001; GPS 2/1 vs. 0, HR: 2.60, P<0.001) and PFS (GPS 2 vs. 0, HR: 2.11, P=0.001; GPS 1 vs. 0, HR: 1.33, P=0.001; GPS 2 vs. 1/0, HR: 2.11, P<0.001; GPS 2/1 vs. 0, HR: 1.62, P<0.001], as well as a lower DCR [GPS 2 vs. 1/0, odds ratio (OR): 0.53, P<0.001, GPS 2/1 vs. 0, OR: 0.51, P<0.001]. It was also found that patients with high mGPS levels had poorer OS (mGPS 2 vs. 0, HR: 3.15, P<0.001; mGPS 1 vs. 0, HR: 1.70, P<0.001; mGPS 2 vs. 1/0, HR: 1.95, P=0.049; mGPS 2/1 vs. 0, HR: 3.14, P=0.041; continuous variables, HR: 1.52, P<0.001) and PFS (mGPS 2 vs. 0, HR: 2.70, P<0.001; mGPS 1 vs. 0, HR: 1.74, P=0.016; mGPS 2 vs. 1/0, HR: 1.91, P=0.044; continuous variables, HR: 1.29, P<0.001), and lower DCR (mGPS 2 vs. 1/0, HR: 0.46, P<0.001). In conclusion, the GPS and mGPS were reliable predictors of outcomes in cancer patients treated with ICIs.

Sarcopenia as a Prognostic Factor for the Outcomes of Surgical Treatment of Colorectal Carcinoma

Background/Objectives: Sarcopenia, defined as the progressive loss of muscle mass and function, is increasingly associated with worse outcomes in the surgical treatment of colorectal cancer (CRC). This paper focuses on analyzing the impact of sarcopenia as a prognostic factor on postoperative outcomes in CRC patients. The aim of the study is to identify the main factors influencing postoperative results. This will be accomplished via bibliometric analysis and highlighting the significance of muscle condition in the preoperative assessment of patients. Methods: The methodological approach involves analyzing bibliographic data from relevant scientific databases focused on sarcopenia and oncological surgery. The study employs a quantitative analysis of citations and collaborations among authors and institutions. The focus will be on research publications from 2013, when we first identified references to sarcopenia in the examined context. Results: The results show that sarcopenia significantly increases the risk of postoperative morbidity and mortality in CRC patients. Network analysis and keyword mapping reveal dominant research topics such as muscle condition, mortality, and postoperative complications. Meanwhile, we identify the need for standardized diagnostic methods for sarcopenia and their integration into clinical practice to improve predictive models and clinical approaches. Conclusions: These findings underscore the importance of interdisciplinary collaboration, preoperative assessment of muscle condition, and the implementation of standardized approaches to improve clinical outcomes for patients.

The Characteristic of Muscle Function for Sarcopenia in Patients with Rheumatoid Arthritis: A Large-Scale Real-World Cross-Sectional Study

Background and Objectives: Sarcopenia is a notable comorbidity of rheumatoid arthritis (RA), affecting about one third of patients. However, the characteristic of muscle function and its association with RA disease remains unknown. Materials and Methods: This cross-sectional study collected clinical data from a real-world Chinese RA cohort. Sarcopenia was defined as both myopenia and low muscle function (LMF). Myopenia was defined as appendicular skeletal muscle mass index (ASMI) < 7.0 kg/m2 in men and <5.7 kg/m2 in women. LMF was defined as low muscle strength (LMS, hand grip < 28 kg in men and <18 kg in women) or low physical performance (LPP, 6 m gait speed < 1.0 m/s). Results: Among 1125 RA patients recruited in this study, 928 RA patients were eligible for analysis. The prevalence of sarcopenia, myopenia, LMF, LMS, and LPP in all RA patients was 36.5%, 46.1%, 69.0%, 57.8%, and 37.1%, respectively. According to their trends in age and disease activity, there were 111 (11.9%) patients in the young (age < 50 years) and remission (CDAI ≤ 2.8) subgroup, 199 (21.4%) patients in the young and active (CDAI > 2.8) subgroup, 198 (21.3%) patients in the old (age ≥ 50 years) and remission subgroup, and 420 (45.2%) patients in the old and active subgroup. Compared with the two remission subgroups, respectively, the young and active subgroup had significantly lower grip strength, higher prevalence of sarcopenia, LMF, and LMS, and worse activity function. After adjustment for potential confounders, multivariate multinominal logistic regression analysis showed that the young and active subgroup was positively associated with sarcopenia (OR = 3.193, 95%CI: 1.477-6.899), LMF (OR = 2.390, 95%CI: 1.207-4.731), and LMS (OR = 3.520, 95%CI: 1.743-7.110). Conclusions: Worse muscle strength, rather than reduced physical performance, is more common in patients with active RA at a young age. It underscores the critical need for early identification and intervention of muscle dysfunction to improve their quality of life.

Preoperative sarcopenia and postoperative accelerated muscle loss negatively impact survival after resection of locally advanced gastric cancer

BACKGROUND

Gastric cancer remains a major health concern worldwide, with locally advanced gastric cancer (LAGC) posing significant challenges due to frequent lymph node metastasis and poor prognosis. While curative gastrectomy with D2 lymph node dissection is the standard treatment, sarcopenia and perioperative skeletal muscle loss (SML) have emerged as critical prognostic factors.

METHODS

We retrospectively analyzed 198 LAGC patients who underwent curative gastrectomy. Preoperative and postoperative sarcopenia were assessed via computed tomography (CT)-derived skeletal muscle index (SMI) at the L3 level. SML was defined based on sex-specific thresholds of SMI changes (%/30 days). Prognostic significance for overall survival (OS) and disease-free survival (DFS) was evaluated using Kaplan-Meier and Cox regression analyses.

RESULTS

The prevalence of sarcopenia increased from 23.7% preoperatively to 33.3% postoperatively. Patients with significant muscle loss (SML) showed worse OS and DFS compared to non-SML patients (P < 0.05). SML was also associated with a higher incidence of Clavien-Dindo grade ≥ 3a complications (P < 0.05). Multivariate analysis identified preoperative sarcopenia (HR = 2.332, P = 0.001), postoperative sarcopenia (HR = 3.189, P = 0.011), and SML (HR = 11.231, P = 0.002) as independent risk factors for OS. Adjuvant chemotherapy significantly improved both OS (HR = 0.532, P = 0.015) and DFS (HR = 0.587, P = 0.041).

CONCLUSIONS

Both preoperative sarcopenia and perioperative SML may negatively impact postoperative prognosis in LAGC patients, suggesting that perioperative evaluation of skeletal muscle mass may help identify high-risk surgical candidates for targeted interventions.

The Improvement of Physical Function and Caregiver Burden by a Multimodal Intervention: A Case Study of Combined Exercise Therapy, Nutritional Guidance, and Hydrogen Gas Inhalation Therapy

The objective of this exploratory case study was to examine the impact of a multifaceted intervention, which incorporated exercise therapy, nutritional guidance, and hydrogen gas inhalation, on the physical function and caregiver burden of an older female patient suspected of having sarcopenia. The methods employed included a three-month program of group exercise and individualized exercise sessions, three times per week, in addition to nutritional guidance and hydrogen gas inhalation therapy. The primary outcome measures included grip strength, walking speed, inflammatory/oxidative stress markers (c-reactive protein (CRP), interleukin-6 (IL-6), 8-hydroxy-2' -deoxyguanosine (8-OHdG)), and caregiver burden, which was assessed by the Family Caregiver Burden Scale (FCS). The results demonstrated that after a period of three months, there was an improvement in grip strength and walking speed. Concurrently, there was a decrease in CRP, IL-6, and 8-OHdG levels. The FCS score demonstrated a shift from the "severe" range to the "normal" range, suggesting a reduction in caregiver burden. The findings of this case study suggest that a multidisciplinary, multifaceted intervention combining exercise therapy, nutritional support, and hydrogen gas inhalation may be effective in enhancing physical function and reducing caregiver burden in older adults with suspected sarcopenia. However, further research is necessary to clarify the independent effects of hydrogen gas inhalation.

Sarcopenia and Cardiogeriatrics: The Links Between Skeletal Muscle Decline and Cardiovascular Aging

Sarcopenia, an age-related decline in skeletal muscle mass, strength, and function, is increasingly recognized as a significant condition in the aging population, particularly among those with cardiovascular diseases (CVD). This review provides a comprehensive synthesis of the interplay between sarcopenia and cardiogeriatrics, emphasizing shared mechanisms such as chronic low-grade inflammation (inflammaging), hormonal dysregulation, oxidative stress, and physical inactivity. Despite advancements in diagnostic frameworks, such as the EWGSOP2 and AWGS definitions, variability in criteria and assessment methods continues to challenge standardization. Key diagnostic tools include dual-energy X-ray absorptiometry (DXA) and bioimpedance analysis (BIA) for muscle mass, alongside functional measures such as grip strength and gait speed. The review highlights the bidirectional relationship between sarcopenia and cardiovascular conditions such as heart failure, aortic stenosis, and atherosclerotic cardiovascular disease, which exacerbate each other through complex pathophysiological mechanisms. Emerging therapeutic strategies targeting the mTOR pathway, NAD+ metabolism, and senescence-related processes offer promise in mitigating sarcopenia's progression. Additionally, integrated interventions combining resistance training, nutritional optimization, and novel anti-aging therapies hold significant potential for improving outcomes. This paper underscores critical gaps in the evidence, including the need for longitudinal studies to establish causality and the validation of advanced therapeutic approaches in clinical settings. Future research should leverage multi-omics technologies and machine learning to identify biomarkers and personalize interventions. Addressing these challenges is essential to reducing sarcopenia's burden and enhancing the quality of life for elderly individuals with comorbid cardiovascular conditions. This synthesis aims to guide future research and promote effective, individualized management strategies.

Factors, mechanisms and improvement methods of muscle strength loss

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

Emerging Targets and Treatments for Sarcopenia: A Narrative Review

BACKGROUND

Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impacting overall health and quality of life in older adults. This narrative review explores emerging targets and potential treatments for sarcopenia, aiming to provide a comprehensive overview of current and prospective interventions.

METHODS

The review synthesizes current literature on sarcopenia treatment, focusing on recent advancements in muscle regeneration, mitochondrial function, nutritional strategies, and the muscle-microbiome axis. Additionally, pharmacological and lifestyle interventions targeting anabolic resistance and neuromuscular junction integrity are discussed.

RESULTS

Resistance training and adequate protein intake remain the cornerstone of sarcopenia management. Emerging strategies include targeting muscle regeneration through myosatellite cell activation, signaling pathways, and chronic inflammation control. Gene editing, stem cell therapy, and microRNA modulation show promise in enhancing muscle repair. Addressing mitochondrial dysfunction through interventions aimed at improving biogenesis, ATP production, and reducing oxidative stress is also highlighted. Nutritional strategies such as leucine supplementation and anti-inflammatory nutrients, along with dietary modifications and probiotics targeting the muscle-microbiome interplay, are discussed as potential treatment options. Hydration and muscle-water balance are emphasized as critical in maintaining muscle health in older adults.

CONCLUSIONS

A combination of resistance training, nutrition, and emerging therapeutic interventions holds potential to significantly improve muscle function and overall health in the aging population. This review provides a detailed exploration of both established and novel approaches for the prevention and management of sarcopenia, highlighting the need for further research to optimize these strategies.

Vascular Impairment, Muscle Atrophy, and Cognitive Decline: Critical Age-Related Conditions

The triad of vascular impairment, muscle atrophy, and cognitive decline represents critical age-related conditions that significantly impact health. Vascular impairment disrupts blood flow, precipitating the muscle mass reduction seen in sarcopenia and the decline in neuronal function characteristic of neurodegeneration. Our limited understanding of the intricate relationships within this triad hinders accurate diagnosis and effective treatment strategies. This review analyzes the interrelated mechanisms that contribute to these conditions, with a specific focus on oxidative stress, chronic inflammation, and impaired nutrient delivery. The aim is to understand the common pathways involved and to suggest comprehensive therapeutic approaches. Vascular dysfunctions hinder the circulation of blood and the transportation of nutrients, resulting in sarcopenia characterized by muscle atrophy and weakness. Vascular dysfunction and sarcopenia have a negative impact on physical function and quality of life. Neurodegenerative diseases exhibit comparable pathophysiological mechanisms that affect cognitive and motor functions. Preventive and therapeutic approaches encompass lifestyle adjustments, addressing oxidative stress, inflammation, and integrated therapies that focus on improving vascular and muscular well-being. Better understanding of these links can refine therapeutic strategies and yield better patient outcomes. This study emphasizes the complex interplay between vascular dysfunction, muscle degeneration, and cognitive decline, highlighting the necessity for multidisciplinary treatment approaches. Advances in this domain promise improved diagnostic accuracy, more effective therapeutic options, and enhanced preventive measures, all contributing to a higher quality of life for the elderly population.

Controlled Cultivation Confers Rhodiola rosea Synergistic Activity on Muscle Cell Homeostasis, Metabolism and Antioxidant Defense in Primary Human Myoblasts

Rhodiola rosea L. is recognized for its adaptogenic properties and ability to promote muscle health, function and recovery from exercise. The plethora of biological effects of this plant is ascribed to the synergism existing among the molecules composing its phytocomplex. In this manuscript, we analyze the activity of a bioactive fraction extracted from Rhodiola rosea L. controlled cultivation. Biological assays were performed on human skeletal myoblasts and revealed that the extract is able to modulate in vitro expression of transcription factors, namely Pax7 and myoD, involved in muscle differentiation and recovery. The extract also promotes ROS scavenging, ATP production and mitochondrial respiration. Untargeted metabolomics further reveals that the mechanism underpinning the plant involves the synergistic interconnection between antioxidant enzymes and the folic/acid polyamine pathway. Finally, by examining the phytochemical profiles of the extract, we identify the specific combination of secondary plant metabolites contributing to muscle repair, recovery from stress and regeneration.

Changes in the gut microbiota of patients with sarcopenia based on 16S rRNA gene sequencing: a systematic review and meta-analysis

Introduction

Sarcopenia, an age-related disease, has become a major public health concern, threatening muscle health and daily functioning in older adults around the world. Changes in the gut microbiota can affect skeletal muscle metabolism, but the exact association is unclear. The richness of gut microbiota refers to the number of different species in a sample, while diversity not only considers the number of species but also the evenness of their abundances. Alpha diversity is a comprehensive metric that measures both the number of different species (richness) and the evenness of their abundances, thereby providing a thorough understanding of the species composition and structure of a community.

Methods

This meta-analysis explored the differences in intestinal microbiota diversity and richness between populations with sarcopenia and non-sarcopenia based on 16 s rRNA gene sequencing and identified new targets for the prevention and treatment of sarcopenia. PubMed, Embase, Web of Science, and Google Scholar databases were searched for cross-sectional studies on the differences in gut microbiota between sarcopenia and non-sarcopenia published from 1995 to September 2023 scale and funnel plot analysis assessed the risk of bias, and performed a meta-analysis with State v.15. 1.

Results

A total of 17 randomized controlled studies were included, involving 4,307 participants aged 43 to 87 years. The alpha diversity of intestinal flora in the sarcopenia group was significantly reduced compared to the non-sarcopenia group: At the richness level, the proportion of Actinobacteria and Fusobacteria decreased, although there was no significant change in other phyla. At the genus level, the abundance of f-Ruminococcaceae; g-Faecalibacterium, g-Prevotella, Lachnoclostridium, and other genera decreased, whereas the abundance of g-Bacteroides, Parabacteroides, and Shigella increased.

Discussion

This study showed that the richness of the gut microbiota decreased with age in patients with sarcopenia. Furthermore, the relative abundance of different microbiota changed related to age, comorbidity, participation in protein metabolism, and other factors. This study provides new ideas for targeting the gut microbiota for the prevention and treatment of sarcopenia.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=475887, CRD475887.

RSU-1 regulates the integrity of dense bodies in muscle cells of aging Caenorhabditis elegans

Muscle contraction is vital for animal survival, and the sarcomere is the fundamental unit for this process. However, the functions of many conserved sarcomere proteins remain unknown, as their mutants do not exhibit obvious defects. To address this, Caenorhabditis elegans was utilized as a model organism to investigate RSU-1 function in the body wall muscle. RSU-1 is found to colocalize with UNC-97 at the dense body and M-line, and it is particularly crucial for regulating locomotion in aging worms, rather than in young worms. This suggests that RSU-1 has a specific function in maintaining muscle function during aging. Furthermore, the interaction between RSU-1 and UNC-97/PINCH is essential for RSU-1 to modulate locomotion, preserve filament structure, and sustain the M-line and dense body throughout aging. Overall, these findings highlight the significant contribution of RSU-1, through its interaction with UNC-97, in maintaining proper muscle cell function in aging worms.

Unraveling the enigma of sarcopenia and sarcopenic obesity in Indian adults with type 2 diabetes - a comparative cross-sectional study

BACKGROUND

Sarcopenia and sarcopenic obesity are growing concerns associated with increasing diabetes incidence, but data from Indian diabetic cohorts are limited. This study examined the prevalence and clinical factors associated with sarcopenia and sarcopenic obesity.

METHODS

In this cross-sectional study, 750 participants aged 35-70 years were recruited by systematic stratification and a fixed quota sampling technique from medical camps and categorized into diabetic (n = 250), nondiabetic (n = 250), and obese nondiabetic (n = 250) groups. The assessments included questionnaires, muscle mass estimation by bioimpedance analysis, and blood tests. Sarcopenia was defined using the Asian Working Group consensus, and sarcopenic obesity was defined as sarcopenia with a BMI ≥ 25 kg/m2. Logistic regression was used to analyze risk factors.

RESULTS

Sarcopenia affected 60% of diabetic patients, 28% of nondiabetic patients, and 38% of nonobese nondiabetic patients (p < 0.001). The prevalence of sarcopenic obesity was 40%, 11%, and 30%, respectively (p < 0.001). Diabetes was associated with 2.3-fold greater odds (95% CI 1.1-4.7) of sarcopenia and 2.4-fold greater odds (1.1-5.0) of sarcopenic obesity after adjustment. A duration greater than 10 years, uncontrolled diabetes, age greater than 65 years, low physical activity, hypertension, and dyslipidemia also independently increased the odds.

CONCLUSION

Indian adults with type 2 diabetes have a high burden of sarcopenia and sarcopenic obesity. Early optimization of diabetes care and lifestyle changes are vital for preserving muscle health.

Oral Administration of Nacre Extract from Pearl Oyster Shells Has Anti-Aging Effects on Skin and Muscle, and Extends the Lifespan in SAMP8 Mice

Pearl oysters have been extensively utilized in pearl production; however, most pearl oyster shells are discarded as industrial waste. In a previous study, we demonstrated that the intraperitoneal administration of pearl oyster shell-derived nacre extract (NE) prevented d-galactose-induced brain and skin aging. In this study, we examined the anti-aging effects of orally administered NE in senescence-accelerated mice (SAMP8). Feeding SAMP8 mice NE prevented the development of aging-related characteristics, such as coarse and dull hair, which are commonly observed in aged mice. Additionally, the NE mitigated muscle aging in SAMP8 mice, such as a decline in grip strength. Histological analysis of skeletal muscle revealed that the NE suppressed the expression of aging markers, cyclin-dependent kinase inhibitor 2A (p16) and cyclin-dependent kinase inhibitor 1 (p21), and increased the expression of sirtuin1 and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1)- α, which are involved in muscle synthesis. These findings suggest that the oral administration of NE suppresses skeletal muscle aging. Moreover, NE administration suppressed skin aging, including a decline in water content. Interestingly, oral administration of NE significantly extended the lifespan of SAMP8 mice, suggesting that its effectiveness as an anti-aging agent of various tissues including skeletal muscle, skin, and adipose tissue.

HucMSCs Delay Muscle Atrophy After Peripheral Nerve Injury Through Exosomes by Repressing Muscle-Specific Ubiquitin Ligases

Cell therapy based on mesenchymal stem cells (MSCs) alleviate muscle atrophy caused by diabetes and aging; however, the impact of human umbilical cord mesenchymal stem cells on muscle atrophy following nerve injury and the underlying mechanisms remain unclear. In this study, we evaluated the therapeutic efficacy of human umbilical cord MSCs (hucMSCs) and hucMSC-derived exosomes (hucMSC-EXOs) for muscle atrophy following nerve injury and identified the underlying molecular mechanisms. Sciatic nerve crush injury in rats and the induction of myotubes in L6 cells were used to determine the ameliorating effect of hucMSCs and hucMSC-EXOs on muscle atrophy. Q-PCR and Western blot analyses were used to measure the expression of muscle-specific ubiquitin ligases Fbxo32 (Atrogin1, MAFbx) and Trim63 (MuRF-1). Dual-luciferase reporter gene experiments were conducted to validate the direct binding of miRNAs to their target genes. Local injection of hucMSCs and hucMSC-EXOs mitigated atrophy in the rat gastrocnemius muscle following sciatic nerve crush injury. In vitro, hucMSC-EXOs alleviated atrophy in L6 myotubes. Mechanistic analysis indicated the upregulation of miR-23b-3p levels in L6 myotubes following hucMSC-EXOs treatment. MiR-23b-3p significantly inhibited the expression of its target genes, Fbxo32 and Trim63, and suppressed myotube atrophy. Notably, an miR-23b-3p inhibitor reversed the inhibitory effect of miR-23b-3p on myotube atrophy in vitro. These results suggest that hucMSCs and their exosomes alleviate muscle atrophy following nerve injury. MiR-23b-3p in exosomes secreted by hucMSCs contributes to this mechanism by inhibiting the muscle-specific ubiquitination ligases Fbxo32 and Trim63.

Evidence that tirzepatide protects against diabetes-related cardiac damages

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are effective antidiabetic drugs with potential cardiovascular benefits. Despite their well-established role in reducing the risk of major adverse cardiovascular events (MACE), their impact on heart failure (HF) remains unclear. Therefore, our study examined the cardioprotective effects of tirzepatide (TZT), a novel glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) receptor agonist.

METHODS

A three-steps approach was designed: (i) Meta-analysis investigation with the primary objective of assessing major adverse cardiovascular events (MACE) occurrence from major randomized clinical trials.; (ii) TZT effects on a human cardiac AC16 cell line exposed to normal (5 mM) and high (33 mM) glucose concentrations for 7 days. The gene expression and protein levels of primary markers related to cardiac fibrosis, hypertrophy, and calcium modulation were evaluated. (iii) In silico data from bioinformatic analyses for generating an interaction map that delineates the potential mechanism of action of TZT.

RESULTS

Meta-analysis showed a reduced risk for MACE events by TZT therapy (HR was 0.59 (95% CI 0.40-0.79, Heterogeneity: r2 = 0.01, I2 = 23.45%, H2 = 1.31). In the human AC16 cardiac cell line treatment with 100 nM TZT contrasted high glucose (HG) levels increase in the expression of markers associated with fibrosis, hypertrophy, and cell death (p < 0.05 for all investigated markers). Bioinformatics analysis confirmed the interaction between the analyzed markers and the associated pathways found in AC16 cells by which TZT affects apoptosis, fibrosis, and contractility, thus reducing the risk of heart failure.

CONCLUSION

Our findings indicate that TZT has beneficial effects on cardiac cells by positively modulating cardiomyocyte death, fibrosis, and hypertrophy in the presence of high glucose concentrations. This suggests that TZT may reduce the risk of diabetes-related cardiac damage, highlighting its potential as a therapeutic option for heart failure management clinical trials. Our study strongly supports the rationale behind the clinical trials currently underway, the results of which will be further investigated to gain insights into the cardiovascular safety and efficacy of TZT.

Role of the ubiquitin-proteasome system in the sarcopenic-like phenotype induced by CCL5/RANTES

Sarcopenia is characterized by reduced muscle strength and mass and a decline in muscle fiber diameter and amount of sarcomeric proteins. Sarcopenia involves the activation of the ubiquitin-proteasome system (UPS). MuRF-1 and atrogin-1 are E3 ubiquitin ligases belonging to UPS, leading to proteolysis mediated by the PSMB 5, 6, and 7 subunits of 20S proteasome. CCL5/RANTES induces a sarcopenic-like effect in muscle cells. The present work explored the impact of CCL5 on UPS components and the influence of UPS on its sarcopenic-like effect. We demonstrated that CCL5 increased MuRF-1 and atrogin-1 protein levels and mRNA levels of subunits PSMB 5, 6, and 7. We used the MG132 inhibitor to elucidate the role of the 20S proteasome in the CCL5-induced sarcopenic-like effect. This inhibitor prevented the decrease in troponin and MHC protein levels and partially prevented the reduction in the diameter of single-isolated FDB muscle fibers induced by CCL5. These findings indicate that CCL5 actively modulates the UPS. Moreover, our results show the direct participation of UPS in the sarcopenic-like phenotype induced by CCL5.

11-beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) gene expression in muscle is linked to reduced skeletal muscle index in sarcopenic patients

BACKGROUND

Glucocorticoids play a significant role in metabolic processes and pathways that impact muscle size, mass, and function. The expression of 11-beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) has been previously described as a major regulator of skeletal muscle function in glucocorticoid-induced muscle atrophy and aging humans. Our study aimed to investigate glucocorticoid metabolism, including the expression of HSD11B1 in skeletal muscle, in patients with sarcopenia.

METHODS

Muscle biopsies were taken from the vastus lateralis muscle of thirty-three patients over 60 years of age with hip fractures. Sarcopenia status was assessed according to the criteria of the European Working Group on Sarcopenia in Older People 2. Skeletal muscle mass was measured by bioelectrical impedance analysis. Cortisol and cortisone concentrations were measured in serum. Gene expression analysis of HSD11B1, NR3C1, FBXO32, and TRIM63 in muscle biopsies was performed. Serial cross sections of skeletal muscle were labeled with myosin heavy chain slow (fiber type-1) and fast (fiber type-2) antibodies.

RESULTS

The study included 33 patients (21 women) with a mean age of 82.5 ± 6.3 years, 17 patients revealed sarcopenic (n = 16 non-sarcopenic). Serum cortisone concentrations were negatively correlated with muscle mass (ß =  - 0.425; p = 0.034) and type-2 fiber diameter (ß =  - 0.591; p = 0.003). Gene expression of HSD11B1 (ß =  - 0.673; p = 0.008) showed a negative correlation with muscle mass in the sarcopenic group. A significant correlation was found for the non-sarcopenic group for NR3C1 (ß = 0.548; p = 0.028) and muscle mass.

CONCLUSION

These findings suggest a pathogenetic role of HSD11B1 in sarcopenic muscle.

Age Is Just a Number: Progress and Obstacles in the Discovery of New Candidate Drugs for Sarcopenia

Sarcopenia is a disease characterized by the progressive loss of skeletal muscle mass and function that occurs with aging. The progression of sarcopenia is correlated with the onset of physical disability, the inability to live independently, and increased mortality. Due to global increases in lifespan and demographic aging in developed countries, sarcopenia has become a major socioeconomic burden. Clinical therapies for sarcopenia are based on physical therapy and nutritional support, although these may suffer from low adherence and variable outcomes. There are currently no clinically approved drugs for sarcopenia. Consequently, there is a large amount of pre-clinical research focusing on discovering new candidate drugs and novel targets. In this review, recent progress in this research will be discussed, along with the challenges that may preclude successful translational research in the clinic. The types of drugs examined include mitochondria-targeting compounds, anti-diabetes agents, small molecules that target non-coding RNAs, protein therapeutics, natural products, and repositioning candidates. In light of the large number of drugs and targets being reported, it can be envisioned that clinically approved pharmaceuticals to prevent the progression or even mitigate sarcopenia may be within reach.

Calsarcin-2 May Play a Compensatory Role in the Development of Obese Sarcopenia

Although obese sarcopenia is a major public health problem with increasing prevalence worldwide, the factors that contribute to the development of obese sarcopenia are still obscure. In order to clarify this issue, a high-fat-diet-induced obese sarcopenia mouse model was utilized. After being fed with a high-fat diet for 24 weeks, decreased motor functions and muscle mass ratios were found in the C57BL/6 mice. In addition, the expression of calsarcin-2 was significantly increased in their skeletal muscle, which was determined by a microarray analysis. In order to clarify the role of calsarcin-2 in muscle, lentiviral vectors containing the calsarcin-2 gene or short hairpin RNA targeted to calsarcin-2 were used to manipulate calsarcin-2 expressions in L6 myoblasts. We found that an overexpression of calsarcin-2 facilitated L6 myoblast differentiation, whereas a calsarcin-2 knockdown delayed myoblast differentiation, as determined by the expression of myogenin. However, the calsarcin-2 knockdown showed no significant effects on myoblast proliferation. In addition, to clarify the relationship between serum calsarcin-2 and sarcopenia, the bilateral gastrocnemius muscle mass per body weight in mice and appendicular skeletal muscle mass index in humans were measured. Although calsarcin-2 facilitated myoblast differentiation, the serum calsarcin-2 concentration was negatively related to skeletal muscle mass index in mice and human subjects. Taken together, calsarcin-2 might facilitate myoblast differentiation and appear to play a compensatory role in sarcopenia.