Myostatin and its Regulation: A Comprehensive Review of Myostatin Inhibiting Strategies

Relationship between myostatin, musclin, nutritional status, and functionality in older Colombian community-dwelling adults: A cross-sectional study

OBJECTIVES

Aging-associated body composition changes lead to a decrease in muscle mass and strength, affecting the functionality of older adults. Myostatin and musclin are myokines that regulate muscle metabolism and may modulate muscle changes during aging. Our objective was to determine the relationship between myostatin, musclin, and nutritional status with physical functionality in older adults.

METHODS

This was a cross-sectional study of a subsample of a stratified random sampling population survey in community-dwelling 60-90-year-old adults of both sexes. Serum myostatin and musclin concentrations were measured using MILLIPLEX technology (Merck Millipore, USA). Trained personnel recorded body mass index (BMI), and waist (WC), calf (CC), and arm (AC) circumferences as indicators of nutritional status. Functionality tests included handgrip strength (GS), walking speed (WS), and Advanced Activities of Daily Living.

RESULTS

Of 101 participants, 55.4% were women, 56.4% were between 60 and 69 years old, 53.5% had abdominal obesity, 23.8% had dynapenia, and 33.7% had low WS. Neither myostatin nor musclin showed significant changes from 60 to 90 years. In a multiple lineal regression model, myostatin showed an inverse correlation with BMI, CC, and AC in men (P < 0.05) but did not explain GS or WS. In a similar analysis, musclin and WC showed an inverse correlation with GS (P < 0.05). Moreover, myostatin was lower in the more physically active men (P < 0.05) but musclin did not show any relationship with the Advanced Activities of Daily Living scale.

CONCLUSIONS

Myostatin and musclin do not decrease with aging and are associated with nutritional and metabolic status. Musclin is associated with dynapenic obesity in older adults.

Cedrol derivative attenuates muscle atrophy through regulation of myostatin transcription via Ca2+-CaMK-FoxO3a signaling pathways

Sarcopenia is a progressive and generalized muscle wasting syndrome characterized by loss of muscle strength and mass. Although many drug candidates have been developed to treat sarcopenia, their results were unsuccessful due to adverse or off-target effects. In this study, we identified a cedrol derivative which is a bioactive sesquiterpene having substantial suppressive effects on muscle atrophy. We demonstrated that the cedrol analog regulated myostatin expression via transcriptional regulation and that the cedrol derivative regulated this expression more effectively than the original form. Cedrol derivative stimulated Ca2+ via the mouse olfactory receptor 23 (MOR23) and induced interactions between phospho-CaMKII and FoxO3a in a calcium-dependent manner. In animal models, the transcript-level expressions of myostatin and MuRF1 were lower in the extensor digitorum longus (EDL) and soleus muscles of mice fed with cedrol-derivative diet. These findings reveal that cedrol derivative suppresses sarcopenia by inhibiting myostatin and MuRF1 expressions in both in vitro and in vivo models, thus suggesting that cedrol derivatives can be potential therapeutic agents for sarcopenia.

The Association Between Myokines, Inflammation, and Nutritional Status in Patients with Multiple Sclerosis

BACKGROUND

Recent studies indicate that in progressive multiple sclerosis (MS)-an inflammatory and degenerative disease of the central nervous system-the biological pathways associated with these effects remain poorly understood. Changes in body weight, whether presenting as overweight or underweight, as well as alterations in adipose and muscle tissue, together with chronic inflammation, may contribute to the disease and influence its course.

OBJECTIVE

This case-control study aimed to measure inflammatory markers and myokine levels (myostatin and irisin), brain-derived neurotrophic factor (BDNF), and IL-6 in the serum of patients with multiple sclerosis and healthy control and assess whether the myokines and cytokines are associated with nutritional status.

METHODS

The study included 92 MS patients and 75 healthy volunteers. Nutritional status was assessed using the NRS (Nutritional Risk Screening) 2002 and GLIM (Global Leadership Initiative on Malnutrition) criteria. The risks of malnutrition or malnutrition were diagnosed based on ESPEN recommendations. Body composition analysis was performed using the BIA method with the InBody 120 analyzer. Routine laboratory parameters (albumin, lipidogram) were measured. Myostatin, irisin, BDNF, IL-6, and hsCRP were measured using ELISA methods. Statistical analysis was conducted using Statistica 13.0 software. Comparisons between the two groups were conducted using Student's t-test for normally distributed variables and the Mann-Whitney U test for non-normally distributed variables; the differences between groups were calculated using either ANOVA or the Kruskal-Wallis test. Post hoc analysis by the Bonferroni method was applied.

RESULTS

In the MS group, high risks of malnutrition (69.0%) and malnutrition (14.0%) were observed. A statistically significant correlation was found between malnutrition (GLIM) and s-albumin (R = 0.2; p < 0.05) and hsCRP (R = 0.23; p < 0.05). The MS patient group displayed significantly lower levels of irisin, higher levels of hsCRP, and lower s-albumin compared to healthy volunteers. Malnourished patients with MS exhibited significantly lower irisin levels, as well as higher hsCRP in comparison to MS patients who were at risk or well nourished. The levels of myostatin, BDNF, and IL6 did not differ depending on nutritional status. Irisin correlated with hsCRP (R Spearman = -0.5; p = 0.01).

CONCLUSIONS

Our findings highlight the interplay between chronic inflammation, nutritional status, and myokines level in multiple sclerosis.

MSTN gene knockout suppresses the activation of lung fibroblasts through the inhibition of the Smad/AKT signaling pathway, thereby ameliorating pulmonary fibrosis

Pulmonary fibrosis is a chronic interstitial lung disease characterized by irreversible, progressive lung scarring and eventual respiratory failure. Fibroblast activation plays a crucial role in the progression of pulmonary fibrosis. Transforming growth factor-β (TGF-β) signaling contributes to pulmonary fibrosis by regulating lung fibroblast activation. Currently, most studies focus on TGF-β1 regulatory effects on fibroblasts, with limited reports on myostatin (MSTN), another member of the same family. This study used MSTN gene knockout (MSTN-/-) boars as animal models to explore MSTN regulatory effects on pulmonary fibrosis by modulating lung fibroblast activation. Studies have demonstrated that MSTN is significantly upregulated in the lungs during pulmonary fibrosis, promoting the activation of downstream Smad and AKT signaling pathways. MSTN-/- inhibits alveolar collapse and interstitial thickening in pulmonary fibrosis pigs and suppresses downstream Smad and AKT signaling. In vitro experiments showed that MSTN-/- inhibits lung fibroblast activation by blocking Smad/AKT signaling. These findings suggest that the MSTN/Smad/AKT signaling axis suppresses pulmonary fibrosis by inhibiting lung fibroblast activation, indicating that MSTN could be a potential therapeutic target for pulmonary fibrosis.

A functional role for myostatin in muscle hyperplasia and hypertrophy revealed by comparative transcriptomics in Yesso scallop Patinopecten yessoensis

Elucidating the molecular regulatory mechanisms underlying muscle growth and development is of profound significance in aquaculture. Yesso scallop is a cold-water bivalve of considerable economic importance, having its primary edible component of adductor muscle. In this study, comparative transcriptomics and histological analysis at different sampling times after Myostatin (MSTN) interference were performed to identify the potential candidate genes potentially involved in muscle growth and development. The comparative transcriptomics revealed that growth factors and cytokines, extracellular matrix proteins and ubiquitin-proteasome system are potentially involved in muscle hypertrophy and hyperplasia. After MSTN interference, striated adductor muscle displays significant muscle hypertrophy (51.77 % increase on day 7 and 59.83 % increase on day 21) and muscle hyperplasia (59.36 % increase on day 7 and 61.83 % increase on day 21). WGCNA identifies the key darkolivegreen module, which may play crucial roles in muscle hyperplasia and hypertrophy within the striated muscle of the scallop. Five key transcription factors (zf-CCCH, zf-C2H2, PPP1R10, LRRFIP2, and Gon4) are identified by analyzing the co-expression patterns of core genes within the module. These findings will aid in understanding the regulatory mechanisms of muscle growth in scallops and provide a basis for genetic improvement in shellfish aquaculture.

Glycyrrhiza uralensis crude water extract and licochalcone A and B to enhance chicken muscle satellite cell differentiation for cultured meat production

Muscle satellite cells (MSCs) are the most commonly used cells in cultured meat research and development. Enhancing MSC proliferation and differentiation while reducing cell culture costs is requisite to commercializing cultured meat. This study explored the effects of Glycyrrhiza uralensis crude water extract (GU-CWE) and licochalcone A and B (Lic A or B) on the proliferation and differentiation of chicken, bovine, and porcine MSCs. While GU-CWE and Lic A and B had negligible effects on bovine and porcine MSCs, GU-CWE significantly enhanced chicken MSC differentiation, and Lic A and B promoted both the proliferation and differentiation of chicken MSCs. Furthermore, GU-CWE was found to mitigate reactive oxygen species activity during chicken MSC differentiation and promote cell proliferation and adhesion in spheroid culture, thereby maintaining a spherical shape. Collectively, this study suggests that GU-CWE and Lic A and B can significantly reduce costs and safely increase the productivity of chicken MSCs in cultured meat production processes.

Targeted Therapy for Skeletal Muscle Fibrosis: Regulation of Myostatin, TGF-β, MMP, and TIMP to Maintain Extracellular Matrix Homeostasis

Muscle fibrosis, defined by the excessive deposition of extracellular matrix (ECM) components, is a key pathological process that hinders muscle regeneration following injury. Despite muscle's inherent regenerative potential, severe or chronic injuries often result in fibrosis, which compromises muscle function and impedes healing. This review explores a range of therapeutic strategies aimed at modulating the molecular pathways involved in muscle fibrosis, with a focus on the inhibition of myostatin and transforming growth factor-β (TGF-β), as well as the regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Some therapy modalities, including physiotherapy and exercise therapy, which are commonly used, have demonstrated the ability to regulate extracellular matrix (ECM) components and promote muscle repair. In addition, the use of TGF-β inhibitors, herbal plants, and other biochemically relevant compounds, holds promise in controlling fibrosis by targeting key signaling pathways that drive ECM accumulation as well as having anti-fibrotic and anti-inflammatory properties. Regenerative medicine, including therapies using stem cell, secretome, and platelet-rich plasma (PRP), have also been used as single or adjuvant treatment for muscle fibrosis, and represents a novel and minimally invasive approach. Although these therapeutic strategies show considerable promise, translating preclinical findings to clinical practice remains challenging owing to variability in patient responses and the complexity of human muscle injuries. In conclusion, a multifaceted approach targeting ECM regulation, either as single treatment or combined treatment, offers a promising avenue for the treatment of muscle fibrosis.

Identification and Validation of Genus/Species-Specific Short InDels in Dairy Ruminants

BACKGROUND

Over the past thirty years, the identification of species-specific molecular markers has significantly advanced our understanding of genetic diversity in both plants and animals. Among these, short InDels have emerged as vital genomic features, contributing more to sequence divergence than single nucleotide polymorphisms do in closely related species. This study aimed to identify specific InDels for Bos taurus, Bubalus bubalis, Capra hircus, and Ovis aries via an in silico approach and validated them in 400 individuals (100 for each species).

RESULTS

We identified and characterized short, specific InDels in the sequences of the CSN1S1, CSN1S2, MSTN, and PRLR genes, which can be used for species identification of Capra hircus, Ovis aries, Bos taurus, and Bubalus bubalis, respectively. We developed a Tetraplex Specific PCR assay to enable efficient discrimination among these species.

CONCLUSIONS

This study highlights the utility of InDels as biallelic, codominant markers that are cost-effective and easy to analyse, providing valuable tools for genetic diversity analysis and species identification.

Sheikh A, Yoshino J, Kanda T, Nagai A, Matsuo M, Yano S. Inhibiting Myostatin Expression by the Antisense Oligonucleotides Improves Muscle Wasting in a Chronic Kidney Disease Mouse Model

Sarcopenia, a serious consequence of chronic kidney disease (CKD), is driven by elevated myostatin (MSTN), a key inhibitor of muscle growth. This study explored the potential of an MSTN-specific antisense oligonucleotide (ASO) in reversing CKD-induced muscle wasting in a mouse model. Thirty-two male C57BL/6J mice were randomly assigned to a non-CKD group (n = 8, regular diet) and a CKD group (n = 24, adenine diet). CKD was induced using a 0.2% adenine-supplemented diet for 4 weeks. Following this, the mice were sub-grouped into CKD (saline, n = 8), CKD + Low-Dose ASO (25 mg/kg ASO, n = 8), and CKD + High-Dose ASO (50 mg/kg ASO, n = 8). ASO was administered via subcutaneous injections for 8 weeks. Muscle mass, treadmill performance, grip strength, and muscle fiber morphology were assessed alongside qPCR and Western blot analysis for MSTN, atrogin-1, and MuRF-1 expression. ASO therapy significantly enhanced muscle mass and function and enlarged muscle fibers while effectively downregulating muscle degradation markers. These improvements occurred without compromising renal function, as confirmed by BUN, creatinine, kidney weight, and histological analysis. This study is the first to demonstrate the efficacy of ASO therapy in mitigating CKD-induced sarcopenia, offering a promising targeted gene therapy with significant clinical implications for improving nutritional status and physical performance in CKD.

Combating chronic kidney disease-associated cachexia: A literature review of recent therapeutic approaches

In 2008, the Society on Sarcopenia, Cachexia, and Wasting Disorders introduced a generic definition for all types of cachexia: "a complex metabolic syndrome associated with the underlying illness characterized by a loss of muscle, with or without fat loss". It is well-known that the presence of inflammatory burden in end-stage renal disease (ESRD) patients may lead to the evolution of cachexia. Since the etiology of cachexia in chronic kidney disease (CKD) is multifactorial, thus the successful treatment must involve several concomitant measures (nutritional interventions, appetite stimulants, and anti-inflammatory pharmacologic agents) to provide integrated effective therapeutic modalities to combat causative factors and alleviate the outcomes of patients. Given the high mortality rate associated with cachexia, developing new therapeutic modalities are prerequisite for ameliorating patients with CKD worldwide. The present review aims to discuss some therapeutic strategies and provide an update on advances in nutritional approaches to counteract cachexia.

The Function of Myostatin in Ameliorating Bone Metabolism Abnormalities in Individuals with Type 2 Diabetes Mellitus by Exercise

PURPOSE

The molecular mechanisms involved in bone metabolism abnormalities in individuals with type 2 diabetes mellitus (T2DM) are a prominent area of investigation within the life sciences field. Myostatin (MSTN), a member of the TGF-β superfamily, serves as a critical negative regulator of skeletal muscle growth and bone metabolism. Current research on the exercise-mediated regulation of MSTN expression predominantly focuses on its role in skeletal muscle. However, due to the intricate and multifaceted mechanical and biochemical interactions between muscle and bone, the precise mechanisms by which exercise modulates MSTN to enhance bone metabolic disorders in T2DM necessitate additional exploration. The objective of this review is to systematically synthesize and evaluate the role of MSTN in the development of bone metabolism disorders associated with T2DM and elucidate the underlying mechanisms influenced by exercise interventions, aiming to offer novel insights and theoretical recommendations for enhancing bone health through physical activity.

METHODS

Relevant articles in Chinese and English up to July 2024 were selected using specific search terms and databases (PubMed, CNKI, Web of Science); 147 studies were finally included after evaluation, and the reference lists were checked for other relevant research.

RESULTS

Myostatin's heightened expression in the bone and skeletal muscle of individuals with T2DM can impede various pathways, such as PI3K/AKT/mTOR and Wnt/β-catenin, hindering osteoblast differentiation and bone mineralization. Additionally, it can stimulate osteoclast differentiation and bone resorption capacity by facilitating Smad2-dependent NFATc1 nuclear translocation and PI3K/AKT/AP-1-mediated pro-inflammatory factor expression pathways, thereby contributing to bone metabolism disorders. Physical exercise plays a crucial role in ameliorating bone metabolism abnormalities in individuals with T2DM. Exercise can activate pathways like Wnt/GSK-3β/β-catenin, thereby suppressing myostatin and downstream Smads, CCL20/CCR6, and Nox4 target gene expression, fostering bone formation, inhibiting bone resorption, and enhancing bone metabolism in T2DM.

CONCLUSION

In the context of T2DM, MSTN has been shown to exacerbate bone metabolic disorders by inhibiting the differentiation of osteoblasts and the process of bone mineralization while simultaneously promoting the differentiation and activity of osteoclasts. Exercise interventions have demonstrated efficacy in downregulating MSTN expression, disrupting its downstream signaling pathways, and enhancing bone metabolism.

Interplay Between Diet, Branched-Chain Amino Acids, and Myokines in Children: Vegetarian Versus Traditional Eating Habits

Background/Objectives: The quality and composition of dietary proteins are crucial during growth, particularly in children who follow vegetarian diets. Branched-chain amino acids (BCAAs: leucine, isoleucine, and valine) and lysine play essential roles in muscle growth, repair, and metabolism and are involved in the regulation of muscle-derived proteins known as myokines. This study aimed to compare the dietary intake and circulating levels of BCAAs, lysine, and myokines-follistatin-like protein 1 (FSTL-1), myostatin, and myonectin-between vegetarian and omnivorous prepubertal children and to explore the impact of diet on muscle metabolism. Methods: Sixty-four healthy Caucasian children aged 4-9 years (forty-two vegetarians and twenty-two omnivores) were assessed for dietary intake using the Dieta 5® (extended version Dieta 5.0) software. Circulating BCAAs and lysine were measured using high-performance liquid chromatography, while myokine concentrations were determined using enzyme-linked immunosorbent assays. Results: Vegetarian children showed significantly lower intakes of total protein, animal protein, BCAAs, and lysine than omnivores. Correspondingly, the circulating levels of isoleucine, valine, lysine, and albumin were significantly reduced in vegetarians. Among myokines, serum myostatin and myonectin levels were comparable between the groups, but vegetarians had significantly lower median FSTL-1 levels 7.7 (6.5-9.4) ng/mL than omnivores 9.7 (7.5-13.9) ng/mL (p = 0.012). In the entire group of children, positive correlations were observed between dietary total and animal protein intake and circulating valine and lysine levels. Dietary animal protein intake was also positively associated with the serum levels of all myokines, whereas plant protein intake was negatively correlated with myonectin concentration. Conclusions: In conclusion, vegetarian diets in prepubertal children are associated with reduced dietary protein quality and lower circulating BCAAs, lysine, and FSTL-1 levels, which may impact muscle metabolism. Optimizing vegetarian diets using high-quality plant proteins with proper essential amino acids could mitigate their deficiencies and support muscle development during critical growth periods.

Long-Term Dietary Consumption of Grapes Alters Phenotypic Expression in Skeletal Muscle of Aged Male and Female Mice

(1) Background: Nutrigenomics investigates how diet influences gene expression and how genetic variation impacts dietary responses. Grapes, rich in phytochemicals, exhibit potential disease-preventive properties through nutrigenomic mechanisms rather than direct chemical interactions. This study aimed to explore the modulation of gene expression in muscle tissue resulting from long-term grape consumption. (2) Methods: A mouse model was employed to assess gene expression in the skeletal muscles of males and females fed a grape-enriched diet versus a bland diet over 2.5 years. Heatmaps and principal component analyses were performed to identify patterns, and pathway analyses using KEGG, GO, and Reactome were conducted. (3) Results: Significant sex-specific gene expression changes were observed, with female phenotypes showing greater alterations and converging toward male-like characteristics. Twenty-five differentially expressed genes associated with muscle health were identified. Up-regulated genes such as Ahsg, Alb, Apoa1, and Arg1, and down-regulated genes including Camp, Lcn2, and Irf4, suggest improved muscle function. (4) Conclusions: Long-term grape consumption appears to enhance female muscle traits toward a male-like phenotype, potentially indicating broader health benefits. Further studies and clinical trials are needed to confirm human applicability and the physiological implications of these findings. Nonetheless, this research underscores the role of nutrigenomics in understanding dietary influences on gene expression and sex-specific responses.

Changes in Protein Metabolism and Early Development of Sarcopenia in Mice With Cholestatic Liver Disease

BACKGROUND

Sarcopenia is a frequent complication of liver cirrhosis. Here, we chose a mouse model of cholestatic liver disease (CLD) to gain mechanistic insights into the development of sarcopenia from the earliest stages of chronic liver injury. Particular attention was paid to protein metabolism, metabolite profiles, and mediators of CLD-induced muscle wasting.

METHODS

Male C57BL/6 J mice underwent bile duct ligation (BDL), sham surgery, or served as untreated controls. The observation phase lasted from the preoperative stage to postoperative day 14. Metabolic cage experiments were performed to determine the nitrogen balance (N-BAL), nitrogen metabolite profiles, and total energy expenditure (TEE) using doubly labelled water. The fractional protein synthesis rate (FPSR) was assessed using 2H5-ring-phenylalanine. Plasma concentrations of inflammatory markers, metabolites, and enzymes associated with liver damage were investigated. Muscle strength and volume were assessed using a grip strength meter and MRI, respectively. Gene expression was analysed by real-time PCR.

RESULTS

BDL caused CLD with necroses and inflammation, increased bilirubin (p < 0.0001) and conjugated bile acids (p < 0.05), and reduced food intake (p < 0.0001) and body weight (p < 0.0001; each vs. sham). Compared to controls, BDL mice showed lower N-BAL (p < 0.05), reduced TEE (p < 0.01), and lower FPSR in the liver (p < 0.05) and quadriceps muscle (p < 0.001). Arginine was the only plasma amino acid that was diminished after BDL compared to controls and sham treatment (p < 0.0001). Reduced muscle strength was observed as early as d3/d4 after BDL (p < 0.001; vs. sham), while muscle volume decreased from d6 to d13 (p < 0.05). In quadriceps muscle, a lower nuclei-to-fibre ratio (p < 0.001) and elevated 1-methyl-histidine (1-MH) (p < 0.001) were detected, whereas 3-MH was increased in the urine of BDL mice (p < 0.001; each vs. sham). The quadriceps muscle of BDL mice contained higher mRNA levels of atrophy-associated genes (Trim63: p < 0.0001, Fbxo32: p < 0.01) and Mstn (p < 0.05), but lower levels of genes involved in mitochondrial function (Cpt-1b: p < 0.05, Pgc-1α: p < 0.01; each vs. sham). In the plasma of BDL mice, elevated protein levels of TNF receptor-1 (p < 0.0001) and HGF-1 (p < 0.05) were observed, while myostatin was diminished (p < 0.05; each vs. sham).

CONCLUSIONS

Sarcopenia occurs early in CLD and is a multicausal process. Relevant pathophysiologies include reduced protein synthesis, degradation of muscle proteins, arginine deficiency, a systemic pro-inflammatory and catabolic state, and muscle toxicity of bile acids. Consequently, the treatment of sarcopenia should focus both on eliminating the cause of the cholestasis and on symptomatic measures such as anti-inflammatory treatment, lowering the bile acid level, and targeted compensation of deficiencies.

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.

Systemic inhibition of bone morphogenetic protein 1.3 as a possible treatment for laminin-related congenital muscular dystrophy

Congenital muscular dystrophy (CMD) is a group of rare neuromuscular disorders typically characterized by the onset of symptoms at birth or within the first two years of life. CMDs are relatively rare, but extremely severe pathological conditions currently without a safe and effective therapeutic solution. Merosin-deficient congenital muscular dystrophy type 1A (MDC1A) is among the most frequent CMDs and it is caused by mutations in the LAMA2 gene that encodes for the α2 chain of laminin-211 (merosin). Laminin-211 is a crucial constituent of the basement membrane that provides muscle fibre stability and signal transduction. Bone morphogenetic protein 1.3 (BMP1.3) is evolutionarily conserved and structurally related to mammalian Tolloid-like metalloproteinase (mTld) that is involved in the processing of procollagens, non-collagenous extracellular matrix proteins, and growth factor-related proteins. Recently, it has been shown that BMP1.3 is present in circulation and its levels are elevated in patients with chronic kidney failure, hepatic fibrosis, and acute myocardial infarction. It has been demonstrated that administering the BMP1.3 antibody ameliorated kidney, liver, and heart function in animal disease models. Furthermore, we observed highly enhanced BMP1.3 gene expression in the skeletal muscles of mice with congenital muscular dystrophy. Therefore, we hypothesize that BMP1.3 inhibition represents a novel therapeutic strategy for reversing the progression of CMD. The development of an anti-BMP1.3 therapy might lead to groundbreaking changes in CMD treatment and provide relief to numerous patients suffering from this disabling disease.

Obesity, Osteoarthritis, and Myokines: Balancing Weight Management Strategies, Myokine Regulation, and Muscle Health

Obesity and osteoarthritis (OA) are increasingly prevalent conditions that are intricately linked, with each exacerbating the other's pathogenesis and worsening patient outcomes. This review explores the dual impact of obesity on OA, highlighting the role of excessive weight in aggravating joint degeneration and the limitations OA imposes on physical activity, which further perpetuates obesity. The role of muscle tissue, particularly the release of myokines during physical activity, is examined in the context of OA and obesity. Myokines such as irisin, IL-6, and myostatin are discussed for their roles in metabolic regulation, inflammation, and tissue repair, offering insights into their potential therapeutic targets. This review emphasizes the importance of supervised weight management methods in parallel with muscle rehabilitation in improving joint health and metabolic balance. The potential for myokine modulation through targeted exercise and weight loss interventions to mitigate the adverse effects of obesity and OA is also discussed, suggesting avenues for future research and therapy development to reduce the burden of these chronic conditions.

Rotenone exposure causes features of Parkinson`s disease pathology linked with muscle atrophy in developing zebrafish embryo

Parkinson's disease (PD) is associated with both genetic and environmental factors; however, sporadic forms of PD account for > 90 % of cases, and PD prevalence has doubled in the past 25 years. Depending on the importance of the environmental factors, various neurotoxins are used to induce PD both in vivo and in vitro. Unlike other neurodegenerative diseases, PD can be induced in vivo using specific neurotoxic chemicals. However, no chemically induced PD model is available because of the sporadic nature of PD. Rotenone is a pesticide that accelerates the induction of PD and exhibits the highest toxicity in fish, unlike other pesticides. Therefore, in this study, we aimed to establish a model exhibiting PD pathologies such as dysfunction of DArgic neuron, aggregation of ɑ-synuclein, and behavioral abnormalities, which are known features of PD pathology, by rotenone exposure at an environmentally relevant concentration (30 nM) in developing zebrafish embryos. Our results provide direct evidence for the association between PD and muscle degeneration by confirming rotenone-induced muscle atrophy. Therefore, we conclude that the rotenone-induced model presents non-motor and motor defects with extensive studies related to muscle atrophy.

A review of myostatin gene mutations: Enhancing meat production and potential in livestock genetic selection

Myostatin (MSTN) is an essential gene that regulates muscle growth and development in livestock animals, influencing meat production and carcass quality. This review looks at MSTN genetic diversity in a variety of animals, including cattle, sheep, goats, and poultry, focusing on correlations between particular mutations and phenotypic parameters such as muscle mass and growth rate. Mutations in the MSTN gene have been linked to desirable features such as greater body weight and higher meat quality, making it an ideal candidate for genetic selection in breeding programs. Animals carrying this mutation frequently transform feed into muscle more efficiently, resulting in faster growth with less feed input. This is advantageous for growers seeking to cut feed costs while raising yields. MSTN-mutated animals convert feed into muscle more efficiently, lowering production costs over time and making them more appealing for commercial breeding operations. Advances in molecular genetics, especially CRISPR-Cas9 technology, have made it possible to precisely manipulate the MSTN gene, allowing for the development of calves with enhanced muscle mass. This article also examines the effects of MSTN variation on meat production efficiency, as well as current issues in animal genetics. This research synthesis emphasizes the significance of MSTN in cattle breeding, specifically its potential as a genetic marker to improve production and meat quality in commercial farming.

Potential Vitamin E Signaling Mediators in Skeletal Muscle

Vitamin E (Vit E) deficiency studies underline the relevance of this vitamin in skeletal muscle (SkM) homeostasis. The knowledge of the effectors and modulators of Vit E action in SkM cells is limited, especially in aging and chronic diseases characterized by a decline in musculoskeletal health. Vit E comprises eight fat-soluble compounds grouped into tocopherols and tocotrienols, which share the basic chemical structure but show different biological properties and potentials to prevent diseases. Vit E has antioxidant and non-antioxidant activities and both favorable and adverse effects depending on the specific conditions and tissues. In this review, we focus on the actual knowledge of Vit E forms in SkM functions and new potential signaling effectors (i.e., bioactive sphingolipids and myokines). The possible advantages of Vit E supplementation in counteracting SkM dysfunctions in sarcopenia and under microgravity will also be discussed.

The Effect of Eight Weeks of High-Intensity Interval Training on Follistatin Gene Expression in the Fast and Slow Twitch Muscles of Rats with Myocardial Infarction

Background

Myocardial infarction causes mitochondrial atrophy and loss of function by reducing mitochondrial volume. Therefore, researchers are interested in finding a way to reduce the injuries and treat them. The study aims to evaluate the effect of 8 weeks of high-intensity interval training on follistatin (FST) gene expression in the fast and slow twitch muscles of rats with myocardial infarction.

Methods

The study was conducted in 2020 at the Cardiac Research Center, Shahid Rajaei University of Medical Sciences (Tehran, Iran). For this purpose, 12 male Wistar rats with myocardial infarction were assigned to the experimental group high-intensity interval training (3 days a week for 30 min, each interval consisting of 4 min of running with 85-90% VO2max intensity and 2 min of active recovery with intensity of 50-60% VO2max for 8 weeks) and a control group. Then, the expression of follistatin in fast and slow twitch muscle contraction genes was investigated as triggers and inhibitors of muscle atrophy. Statistical data were analyzed with SPSS18 (α≥0.05). To determine the normality of the data, the Kolmogorov-Smirnov test was used, and in the case of normality of the data distribution, the independent samples t test was used.

Results

Independent t test results showed that FST gene expression in the slow twitch (ST) muscle contraction group was significantly decreased compared with the control group (P<0.001). Moreover, the expression of the FST gene in fast twitch muscles was significantly increased in the severe exercise group compared with the control group (P<0.001).

Conclusion

Overall, 8 weeks of intense intermittent exercise decreased FST gene expression in slow and fast twitch muscles in rats with myocardial infarction.

Alzheimer's Disease: Understanding Motor Impairments

Alzheimer's disease (AD), the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, profoundly impacts health and quality of life. While cognitive impairments-such as memory loss, attention deficits, and disorientation-predominate in AD, motor symptoms, though common, remain underexplored. These motor symptoms, including gait disturbances, reduced cardiorespiratory fitness, muscle weakness, sarcopenia, and impaired balance, are often associated with advanced stages of AD and contribute to increased mortality. Emerging evidence, however, suggests that motor symptoms may be present in earlier stages and can serve as predictive markers for AD in older adults. Despite a limited understanding of the underlying mechanisms driving these motor symptoms, several key pathways have been identified, offering avenues for further investigation. This review provides an in-depth analysis of motor symptoms in AD, discussing its progression, potential mechanisms, and therapeutic strategies. Addressing motor symptoms alongside cognitive decline may enhance patient functionality, improve quality of life, and support more comprehensive disease management strategies.

A MSTNDel73C mutation with FGF5 knockout sheep by CRISPR/Cas9 promotes skeletal muscle myofiber hyperplasia

Mutations in the well-known Myostatin (MSTN) produce a 'double-muscle' phenotype, which makes it commercially invaluable for improving livestock meat production and providing high-quality protein for humans. However, mutations at different loci of the MSTN often produce a variety of different phenotypes. In the current study, we increased the delivery ratio of Cas9 mRNA to sgRNA from the traditional 1:2 to 1:10, which improves the efficiency of the homozygous mutation of biallelic gene. Here, a MSTNDel73C mutation with FGF5 knockout sheep, in which the MSTN and FGF5 dual-gene biallelic homozygous mutations were produced via the deletion of 3-base pairs of AGC in the third exon of MSTN, resulting in cysteine-depleted at amino acid position 73, and the FGF5 double allele mutation led to inactivation of FGF5 gene. The MSTNDel73C mutation with FGF5 knockout sheep highlights a dominant 'double-muscle' phenotype, which can be stably inherited. Both F0 and F1 generation mutants highlight the excellent trait of high-yield meat with a smaller cross-sectional area and higher number of muscle fibers per unit area. Mechanistically, the MSTNDel73C mutation with FGF5 knockout mediated the activation of FOSL1 via the MEK-ERK-FOSL1 axis. The activated FOSL1 promotes skeletal muscle satellite cell proliferation and inhibits myogenic differentiation by inhibiting the expression of MyoD1, and resulting in smaller myotubes. In addition, activated ERK1/2 may inhibit the secondary fusion of myotubes by Ca2+-dependent CaMKII activation pathway, leading to myoblasts fusion to form smaller myotubes.

New Insight in Using of Mesenchyme Stem Cell Conditioning Medium for the Impaired Muscle related Biomarkers: In vivo Study with Rat Model

AIMS AND OBJECTIVES

This study aimed to investigate the effects of Umbilical Cord Mesencymal Stem Cell Conditioning Medium (UC MSC-CM) administration on body weight recovery and the level of four molecular biomarkers, namely Superoxide Dismutase (SOD), vascular Endothelial Growth Factor (VEGF), C-Reactive Protein (CRP), and myostatin.

MATERIALS AND METHODS

Secretome was injected intramuscularly twice at 1.5 mL (day 7 and 14) into the right thigh of high-dose, short-term galactose-induced aging rats. The data of day 7 (before) and day 21 (after the administration) were evaluated. The body weights and the four biomarkers were measured before (day 7) and after intervention (day 21).

RESULTS

This study showed that the UC MSC-CM intramuscular administrations did not influence body weight regeneration. However, it could increase SOD and VEGF levels and decrease CRP and myostatin levels.

CONCLUSION

Treatment with UC MSC-CM is a promising and potential agent in treating sarcopenia.

Taldefgrobep Alfa and the Phase 3 RESILIENT Trial in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a rare, genetic neurodegenerative disorder caused by insufficient production of survival motor neuron (SMN) protein. Diminished SMN protein levels lead to motor neuron loss, causing muscle atrophy and weakness that impairs daily functioning and reduces quality of life. SMN upregulators offer clinical improvements and increased survival in SMA patients, although significant unmet needs remain. Myostatin, a TGF-β superfamily signaling molecule that binds to the activin II receptor, negatively regulates muscle growth; myostatin inhibition is a promising therapeutic strategy for enhancing muscle. Combining myostatin inhibition with SMN upregulation, a comprehensive therapeutic strategy targeting the whole motor unit, offers promise in SMA. Taldefgrobep alfa is a novel, fully human recombinant protein that selectively binds to myostatin and competitively inhibits other ligands that signal through the activin II receptor. Given a robust scientific and clinical rationale and the favorable safety profile of taldefgrobep in patients with neuromuscular disease, the RESILIENT phase 3, randomized, placebo-controlled trial is investigating taldefgrobep as an adjunct to SMN upregulators in SMA (NCT05337553). This manuscript reviews the role of myostatin in muscle, explores the preclinical and clinical development of taldefgrobep and introduces the phase 3 RESILIENT trial of taldefgrobep in SMA.

Roles of natural products on myokine expression and secretion in skeletal muscle atrophy

Skeletal muscles serve both in movement and as endocrine organs. Myokines secreted by skeletal muscles activate biological functions within muscles and throughout the body via autocrine, paracrine, and/or endocrine pathways. Skeletal muscle atrophy can influence myokine expression and secretion, while myokines can impact the structure and function of skeletal muscles. Regulating the expression and secretion of myokines through the pharmacological approach is a strategy for alleviating skeletal muscle atrophy. Natural products possess complex structures and chemical properties. Previous studies have demonstrated that various natural products exert beneficial effects on skeletal muscle atrophy. This article reviewed the regulatory effects of natural products on myokines and summarized the research progress on skeletal muscle atrophy associated with myokine regulation. The focus is on how small-molecule natural products affect the regulation of interleukin 6 (IL-6), irisin, myostatin, IGF-1, and FGF-21 expression. We contend that the development of small-molecule natural products targeting the regulation of myokines holds promise in combating skeletal muscle atrophy.

Understanding Secondary Sarcopenia Development in Young Adults Using Pig Model with Chronic Pancreatitis

Chronic pancreatitis (CP) in young individuals may lead to disease-related secondary sarcopenia (SSARC), characterized by muscle loss and systemic inflammation. In this study, CP was induced in young pigs, and serum levels of key hormones, muscle fiber diameters in various muscles, and the mRNA expression of genes related to oxidative stress and programmed cell death were assessed. A decrease in muscle fiber diameters was observed in SSARC pigs, particularly in the longissimus and diaphragm muscles. Hormonal analysis revealed alterations in dehydroepiandrosterone, testosterone, oxytocin, myostatin, and cortisol levels, indicating a distinct hormonal response in SSARC pigs compared to controls. Oxytocin levels in SSARC pigs were significantly lower and myostatin levels higher. Additionally, changes in the expression of catalase (CAT), caspase 8 (CASP8), B-cell lymphoma 2 (BCL2), and BCL2-associated X protein (BAX) mRNA suggested a downregulation of oxidative stress response and apoptosis regulation. A reduced BAX/BCL2 ratio in SSARC pigs implied potential caspase-independent cell death pathways. The findings highlight the complex interplay between hormonal changes and muscle degradation in SSARC, underscoring the need for further research into the apoptotic and inflammatory pathways involved in muscle changes due to chronic organ inflammation in young individuals.

Myostatin's marvels: From muscle regulator to diverse implications in health and disease

Myostatin, a member of the transforming growth factor-β superfamily, is a pivotal regulator of skeletal muscle growth in mammals. Its discovery has sparked significant interest due to its multifaceted roles in various physiological processes and its potential therapeutic implications. This review explores the diverse functions of myostatin in skeletal muscle development, maintenance and pathology. We delve into its regulatory mechanisms, including its interaction with other signalling pathways and its modulation by various factors such as microRNAs and mechanical loading. Furthermore, we discuss the therapeutic strategies aimed at targeting myostatin for the treatment of muscle-related disorders, including cachexia, muscular dystrophy and heart failure. Additionally, we examine the impact of myostatin deficiency on craniofacial morphology and bone development, shedding light on its broader implications beyond muscle biology. Through a comprehensive analysis of the literature, this review underscores the importance of further research into myostatin's intricate roles and therapeutic potential in human health and disease.

Comparative Analysis of Myokines and Bone Metabolism Markers in Prepubertal Vegetarian and Omnivorous Children

The role of bone and muscle as endocrine organs may be important contributing factors for children's growth and development. Myokines, secreted by muscle cells, play a role in regulating bone metabolism, either directly or indirectly. Conversely, markers of bone metabolism, reflecting the balance between bone formation and bone resorption, can also influence myokine secretion. This study investigated a panel of serum myokines and their relationships with bone metabolism markers in children following vegetarian and omnivorous diets. A cohort of sixty-eight healthy prepubertal children, comprising 44 vegetarians and 24 omnivores, participated in this study. Anthropometric measurements, dietary assessments, and biochemical analyses were conducted. To evaluate the serum concentrations of bone markers and myokines, an enzyme-linked immunosorbent assay (ELISA) was used. The studied children did not differ regarding their serum myokine levels, except for a higher concentration of decorin in the vegetarian group (p = 0.020). The vegetarians demonstrated distinct pattern of bone metabolism markers compared to the omnivores, with lower levels of N-terminal propeptide of type I procollagen (P1NP) (p = 0.001) and elevated levels of C-terminal telopeptide of type I collagen (CTX-I) (p = 0.018). Consequently, the P1NP/CTX-I ratio was significantly decreased in the vegetarians. The children following a vegetarian diet showed impaired bone metabolism with reduced bone formation and increased bone resorption. Higher levels of decorin, a myokine involved in collagen fibrillogenesis and essential for tissue structure and function, may suggest a potential compensatory mechanism contributing to maintaining bone homeostasis in vegetarians. The observed significant positive correlations between myostatin and bone metabolism markers, including P1NP and soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), suggest an interplay between muscle and bone metabolism, potentially through the RANK/RANKL/OPG signaling pathway.

Impaired skeletal muscle regeneration in diabetes: From cellular and molecular mechanisms to novel treatments

Diabetes represents a major public health concern with a considerable impact on human life and healthcare expenditures. It is now well established that diabetes is characterized by a severe skeletal muscle pathology that limits functional capacity and quality of life. Increasing evidence indicates that diabetes is also one of the most prevalent disorders characterized by impaired skeletal muscle regeneration, yet underlying mechanisms and therapeutic treatments remain poorly established. In this review, we describe the cellular and molecular alterations currently known to occur during skeletal muscle regeneration in people with diabetes and animal models of diabetes, including its associated comorbidities, e.g., obesity, hyperinsulinemia, and insulin resistance. We describe the role of myogenic and non-myogenic cell types on muscle regeneration in conditions with or without diabetes. Therapies for skeletal muscle regeneration and gaps in our knowledge are also discussed, while proposing future directions for the field.

Sarcopenia predicts short-term treatment-related toxicity in patients undergoing curative-intent therapy for head and neck cancer: A systematic review and meta-analysis

Sarcopenia is an increasingly recognized biomarker associated with poorer outcomes. The objective of this study was to ascertain the effect of sarcopenia on treatment tolerance and short-term toxicity in head and neck cancer (HNC). A systematic review was performed using multiple databases. An inverse-variation, random-effects model was used to perform the meta-analysis to evaluate the effect of sarcopenia on severe treatment toxicity and poor treatment tolerance. Sixteen observational studies, including 3187 patients with HNC, were analyzed. The combined odds ratio (OR) for severe treatment toxicity and tolerance was 2.22 (95%CI 1.50-3.29) and 1.40 (95%CI 0.84-2.32), respectively. The effect of sarcopenia on short-term severe treatment toxicity was similar with upfront surgery (OR 2.03, 95%CI 1.22-3.37) and definitive radiotherapy (OR 2.24, 95%CI 1.18-4.27) Patients with sarcopenia are more than twice as likely to suffer a short-term treatment-related toxicity when undergoing curative-intent HNC treatment.

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.

A perspective on muscle phenotyping in musculoskeletal research

Musculoskeletal research should synergistically investigate bone and muscle to inform approaches for maintaining mobility and to avoid bone fractures. The relationship between sarcopenia and osteoporosis, integrated in the term 'osteosarcopenia', is underscored by the close association shown between these two conditions in many studies, whereby one entity emerges as a predictor of the other. In a recent workshop of Working Group (WG) 2 of the EU Cooperation in Science and Technology (COST) Action 'Genomics of MusculoSkeletal traits Translational Network' (GEMSTONE) consortium (CA18139), muscle characterization was highlighted as being important, but currently under-recognized in the musculoskeletal field. Here, we summarize the opinions of the Consortium and research questions around translational and clinical musculoskeletal research, discussing muscle phenotyping in human experimental research and in two animal models: zebrafish and mouse.

Inflammatory Cytokine-Induced Muscle Atrophy and Weakness Can Be Ameliorated by an Inhibition of TGF-β-Activated Kinase-1

Chronic inflammation causes muscle wasting. Because most inflammatory cytokine signals are mediated via TGF-β-activated kinase-1 (TAK1) activation, inflammatory cytokine-induced muscle wasting may be ameliorated by the inhibition of TAK1 activity. The present study was undertaken to clarify whether TAK1 inhibition can ameliorate inflammation-induced muscle wasting. SKG/Jcl mice as an autoimmune arthritis animal model were treated with a small amount of mannan as an adjuvant to enhance the production of TNF-α and IL-1β. The increase in these inflammatory cytokines caused a reduction in muscle mass and strength along with an induction of arthritis in SKG/Jcl mice. Those changes in muscle fibers were mediated via the phosphorylation of TAK1, which activated the downstream signaling cascade via NF-κB, p38 MAPK, and ERK pathways, resulting in an increase in myostatin expression. Myostatin then reduced the expression of muscle proteins not only via a reduction in MyoD1 expression but also via an enhancement of Atrogin-1 and Murf1 expression. TAK1 inhibitor, LL-Z1640-2, prevented all the cytokine-induced changes in muscle wasting. Thus, TAK1 inhibition can be a new therapeutic target of not only joint destruction but also muscle wasting induced by inflammatory cytokines.

Role of Myostatin in Rheumatoid Arthritis: A Review of the Clinical Impact

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects synovial joints and that frequently involves extra-articular organs. A multiplicity of interleukins (IL) participates in the pathogenesis of RA, including IL-6, IL-1β, transforming growth factor-beta (TGF-β), and tumor necrosis factor (TNF)-α; immune cells such as monocytes, T and B lymphocytes, and macrophages; and auto-antibodies, mainly rheumatoid factor and anti-citrullinated protein antibodies (ACPAs). Skeletal muscle is also involved in RA, with many patients developing muscle wasting and sarcopenia. Several mechanisms are involved in the myopenia observed in RA, and one of them includes the effects of some interleukins and myokines on myocytes. Myostatin is a myokine member of the TGF-β superfamily; the overproduction of myostatin acts as a negative regulator of growth and differentiates the muscle fibers, limiting their number and size. Recent studies have identified abnormalities in the serum myostatin levels of RA patients, and these have been found to be associated with muscle wasting and other manifestations of severe RA. This review analyzes recent information regarding the relationship between myostatin levels and clinical manifestations of RA and the relevance of myostatin as a therapeutic target for future research.

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.

Assessment of muscle endocrine function and inflammatory signalling in male school children following a physical activity programme

BACKGROUND & AIMS

Regular and planned physical activity can diminish the risk of numerous illnesses. However, school children and teenagers often exercise intermittently and for brief periods, restricting potential benefits. Furthermore, previous studies mainly focused on body composition, without providing molecular mechanisms elucidating the role of physical activity in muscle tissue and inflammatory signalling. The objective of this study was to determine the effect of a vigorous physical activity intervention on endocrine muscle function and cytokine output in children.

METHODS

103 boys were divided into two groups: control (n = 51, did not perform additional physical activity) and exercise (n = 52, performed vigorous physical activity). Body composition measurements, endocrine muscle function and inflammatory signalling biomarkers were assessed at enrolment and after 6 months of intervention.

RESULTS

No statistical significance was found for fractalkine, oncostatin, EGF, TNF-α and eotaxin. However, LIF, FBAP3, IL-6, FGF21 and IL-15 increased in the exercise group at the end of the protocol, though myostatin got decreased. In contrast, IFN-γ was increased in the exercise group at the beginning and end of the exercise protocol, IL-10 was also increased in this group, IL-1α decreased in the exercise group before and after the exercise protocol, and IP-10 and MCP-1 also decreased in the exercise group.

CONCLUSION

It can be affirmed that a physical activity programme for boys was shown to produce changes in body composition (decreased fat mass, increased lean mass) and in markers of endocrine muscle function and cytokine release. It is possible that these changes, if sustained, could reduce the risk of chronic disease.

Licochalcone A and B enhance muscle proliferation and differentiation by regulating Myostatin

BACKGROUND

Myostatin (MSTN) inhibition has demonstrated promise for the treatment of diseases associated with muscle loss. In a previous study, we discovered that Glycyrrhiza uralensis (G. uralensis) crude water extract (CWE) inhibits MSTN expression while promoting myogenesis. Furthermore, three specific compounds of G. uralensis, namely liquiritigenin, tetrahydroxymethoxychalcone, and Licochalcone B (Lic B), were found to promote myoblast proliferation and differentiation, as well as accelerate the regeneration of injured muscle tissue.

PURPOSE

The purpose of this study was to build on our previous findings on G. uralensis and demonstrate the potential of its two components, Licochalcone A (Lic A) and Lic B, in muscle mass regulation (by inhibiting MSTN), aging and muscle formation.

METHODS

G. uralensis, Lic A, and Lic B were evaluated thoroughly using in silico, in vitro and in vivo approaches. In silico analyses included molecular docking, and dynamics simulations of these compounds with MSTN. Protein-protein docking was carried out for MSTN, as well as for the docked complex of MSTN-Lic with its receptor, activin type IIB receptor (ACVRIIB). Subsequent in vitro studies used C2C12 cell lines and primary mouse muscle stem cells to acess the cell proliferation and differentiation of normal and aged cells, levels of MSTN, Atrogin 1, and MuRF1, and plasma MSTN concentrations, employing techniques such as western blotting, immunohistochemistry, immunocytochemistry, cell proliferation and differentiation assays, and real-time RT-PCR. Furthermore, in vivo experiments using mouse models focused on measuring muscle fiber diameters.

RESULTS

CWE of G. uralensis and two of its components, namely Lic A and B, promote myoblast proliferation and differentiation by inhibiting MSTN and reducing Atrogin1 and MuRF1 expressions and MSTN protein concentration in serum. In silico interaction analysis revealed that Lic A (binding energy -6.9 Kcal/mol) and B (binding energy -5.9 Kcal/mol) bind to MSTN and reduce binding between it and ACVRIIB, thereby inhibiting downstream signaling. The experimental analysis, which involved both in vitro and in vivo studies, demonstrated that the levels of MSTN, Atrogin 1, and MuRF1 were decreased when G. uralensis CWE, Lic A, or Lic B were administered into mice or treated in the mouse primary muscle satellite cells (MSCs) and C2C12 myoblasts. The diameters of muscle fibers increased in orally treated mice, and the differentiation and proliferation of C2C12 cells were enhanced. G. uralensis CWE, Lic A, and Lic B also promoted cell proliferation in aged cells, suggesting that they may have anti-muslce aging properties. They also reduced the expression and phosphorylation of SMAD2 and SMAD3 (MSTN downstream effectors), adding to the evidence that MSTN is inhibited.

CONCLUSION

These findings suggest that CWE and its active constituents Lic A and Lic B have anti-mauscle aging potential. They also have the potential to be used as natural inhibitors of MSTN and as therapeutic options for disorders associated with muscle atrophy.

Potential Biomarkers of Resilience to Microgravity Hazards in Astronauts

Space exploration exposes astronauts to the unique environment of microgravity, which poses significant health challenges. Identifying biomarkers that can predict an individual's resilience to the stressors of microgravity holds great promise for optimizing astronaut selection and developing personalized countermeasures. This narrative review examines the principal health risks associated with microgravity and explores potential biomarkers indicative of resilience. The biomarkers being evaluated represent a broad spectrum of physiological domains, including musculoskeletal, neurological, immunological, gastrointestinal, cardiovascular, and cutaneous systems. Earth-based microgravity analogs, such as dry immersion and head-down tilt bed rest, may provide valuable platforms to validate candidate biomarkers. However, biomarker sensitivity and specificity must be further evaluated to ensure efficacy and reliability. Establishing a panel of biomarkers predictive of resilience to microgravity-induced health risks would significantly enhance astronaut health and mission success, especially for long-duration exploration missions. Insights gained may also translate to health conditions on Earth characterized by reduced physical activity and mechanical loading.

Sarcopenia and Diabetes: A Detrimental Liaison of Advancing Age

Sarcopenia is an age-related clinical complaint characterized by the progressive deterioration of skeletal muscle mass and strength over time. Type 2 diabetes (T2D) is associated with faster and more relevant skeletal muscle impairment. Both conditions influence each other, leading to negative consequences on glycemic control, cardiovascular risk, general health status, risk of falls, frailty, overall quality of life, and mortality. PubMed/Medline, Scopus, Web of Science, and Google Scholar were searched for research articles, scientific reports, observational studies, clinical trials, narrative and systematic reviews, and meta-analyses to review the evidence on the pathophysiology of di-abetes-induced sarcopenia, its relevance in terms of glucose control and diabetes-related outcomes, and diagnostic and therapeutic challenges. The review comprehensively addresses key elements for the clinical definition and diagnostic criteria of sarcopenia, the pathophysiological correlation be-tween T2D, sarcopenia, and related outcomes, a critical review of the role of antihyperglycemic treatment on skeletal muscle health, and perspectives on the role of specific treatment targeting myokine signaling pathways involved in glucose control and the regulation of skeletal muscle metabolism and trophism. Prompt diagnosis and adequate management, including lifestyle inter-vention, health diet programs, micronutrient supplementation, physical exercise, and pharmaco-logical treatment, are needed to prevent or delay skeletal muscle deterioration in T2D.

Myostatin and the Heart

Myostatin (growth differentiation factor 8) is a member of the transforming growth factor-β superfamily. It is secreted mostly by skeletal muscles, although small amounts of myostatin are produced by the myocardium and the adipose tissue as well. Myostatin binds to activin IIB membrane receptors to activate the downstream intracellular canonical Smad2/Smad3 pathway, and additionally acts on non-Smad (non-canonical) pathways. Studies on transgenic animals have shown that overexpression of myostatin reduces the heart mass, whereas removal of myostatin has an opposite effect. In this review, we summarize the potential diagnostic and prognostic value of this protein in heart-related conditions. First, in myostatin-null mice the left ventricular internal diameters along with the diastolic and systolic volumes are larger than the respective values in wild-type mice. Myostatin is potentially secreted as part of a negative feedback loop that reduces the effects of the release of growth-promoting factors and energy reprogramming in response to hypertrophic stimuli. On the other hand, both human and animal data indicate that myostatin is involved in the development of the cardiac cachexia and heart fibrosis in the course of chronic heart failure. The understanding of the role of myostatin in such conditions might initiate a development of targeted therapies based on myostatin signaling inhibition.

Therapeutic Applications of Ginseng Natural Compounds for Health Management

Ginseng is usually consumed as a daily food supplement to improve health and has been shown to benefit skeletal muscle, improve glucose metabolism, and ameliorate muscle-wasting conditions, cardiovascular diseases, stroke, and the effects of aging and cancers. Ginseng has also been reported to help maintain bone strength and liver (digestion, metabolism, detoxification, and protein synthesis) and kidney functions. In addition, ginseng is often used to treat age-associated neurodegenerative disorders, and ginseng and ginseng-derived natural products are popular natural remedies for diseases such as diabetes, obesity, oxidative stress, and inflammation, as well as fungal, bacterial, and viral infections. Ginseng is a well-known herbal medication, known to alleviate the actions of several cytokines. The article concludes with future directions and significant application of ginseng compounds for researchers in understanding the promising role of ginseng in the treatment of several diseases. Overall, this study was undertaken to highlight the broad-spectrum therapeutic applications of ginseng compounds for health management.

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.

Sarcopenic Obesity: Involvement of Oxidative Stress and Beneficial Role of Antioxidant Flavonoids

Sarcopenic obesity, which refers to concurrent sarcopenia and obesity, is characterized by decreased muscle mass, strength, and performance along with abnormally excessive fat mass. Sarcopenic obesity has received considerable attention as a major health threat in older people. However, it has recently become a health problem in the general population. Sarcopenic obesity is a major risk factor for metabolic syndrome and other complications such as osteoarthritis, osteoporosis, liver disease, lung disease, renal disease, mental disease and functional disability. The pathogenesis of sarcopenic obesity is multifactorial and complicated, and it is caused by insulin resistance, inflammation, hormonal changes, decreased physical activity, poor diet and aging. Oxidative stress is a core mechanism underlying sarcopenic obesity. Some evidence indicates a protective role of antioxidant flavonoids in sarcopenic obesity, although the precise mechanisms remain unclear. This review summarizes the general characteristics and pathophysiology of sarcopenic obesity and focuses on the role of oxidative stress in sarcopenic obesity. The potential benefits of flavonoids in sarcopenic obesity have also been discussed.

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.

Serum Myostatin among Excessive Drinkers

Myostatin acts as a negative regulator of muscle growth. Its effect on fat mass is subject to debate. Among alcoholics, there is a high prevalence of muscle atrophy, and increased fat deposition has been also described in these patients. Myostatin could be involved in these alterations, but its relationships with body composition have been scarcely studied in alcoholic patients. To analyze the behavior of myostatin among alcoholics and its relationship with alcohol intake, liver function, and body composition. We investigated serum myostatin in 59 male patients and 18 controls. Patients were all heavy drinkers admitted with organic complications related to excessive ethanol ingestion. Densitometry analysis was used to assess body composition in 46 patients. Handgrip was assessed in 51 patients. Patients showed lower myostatin values than controls (Z = 3.80; p < 0.001). There was a significant relationship between myostatin and fat at the right leg (ρ = 0.32; p = 0.028), left leg (ρ = 0.32; p = 0.028), trunk (ρ = 0.31, p = 0.038), total fat proport ion (ρ = 0.33, p = 0.026), and gynecoid fat distribution (ρ = 0.40, p = 0.006) but not with lean mass (total lean ρ = 0.07; p = 0.63; trunk lean ρ = 0.03; p = 0.85; lower limbs ρ = 0.08; p = 0.58; upper limbs ρ = 0.04 p = 0.82; android ρ = 0.02; p = 0.88, or gynoid lean mass ρ = 0.20; p = 0.19). In total, 80.43% of patients showed at least one criterion of osteosarcopenic adiposity (OSA). Myostatin was related to OSA obesity. We also observed higher myostatin values among patients with body mass index > 30 kg/m². Serum myostatin was lower among excessive drinkers, and it was related to increased fat deposition among these patients but not to lean mass, handgrip, or bone mineral density.

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.

The roles of growth factors and hormones in the regulation of muscle satellite cells for cultured meat production

Cultured meat is a potential sustainable food generated by the in vitro myogenesis of muscle satellite (stem) cells (MSCs). The self-renewal and differentiation properties of MSCs are of primary interest for cultured meat production. MSC proliferation and differentiation are influenced by a variety of growth factors such as insulin-like growth factors (IGF-1 and IGF-2), transforming growth factor beta (TGF-β), fibroblast growth factors (FGF-2 and FGF-21), platelet-derived growth factor (PDGF) and hepatocyte growth factor (HGF) and by hormones like insulin, testosterone, glucocorticoids, and thyroid hormones. In this review, we investigated the roles of growth factors and hormones during cultured meat production because these factors provide signals for MSC growth and structural stability. The aim of this article is to provide the important idea about different growth factors such as FGF (enhance the cell proliferation and differentiation), IGF-1 (increase the number of myoblasts), PDGF (myoblast proliferation), TGF-β1 (muscle repair) and hormones such as insulin (cell survival and growth), testosterone (muscle fiber size), dexamethasone (myoblast proliferation and differentiation), and thyroid hormones (amount and diameter of muscle fibers and determine the usual pattern of fiber distributions) as media components during myogenesis for cultured meat production.

Effects of functional training with blood occlusion on the irisin, follistatin, and myostatin myokines in elderly men

Background

This study aimed to determine the efficacy of functional training with and without blood flow restriction (BFR) on muscle hypertrophy indices and strength in older men.

Methods

Thirty older adults (67.7 ± 5.8 years) were randomly assigned to three groups: functional training (FT), functional training with BFR (FTBFR), and control (C). Participants in experimental groups were trained in three sessions per week for six weeks. They performed 11 whole body exercises, in 2–4 sets of 10 repetitions. FTBFR group wore pneumatic cuffs on their extremities that began with 50% of estimated arterial occlusion pressure which increased by 10% every two weeks. Blood samples were obtained, and static strength tests were evaluated at baseline and after the training program. A One-Way Analysis of Covariance was used to interpret the data.

Results

A significant increase in follistatin levels (p = 0.002) and reduction in myostatin levels (p = 0.001) were observed in FT and FTBFR groups; there was a considerable increase in the F:M ratio in both training groups (p = 0.001), whereas it decreased in C group. These changes were accompanied by significant improvements in handgrip (p = 0.001) and shoulder girdle (p = 0.001) strength in both experimental groups, especially in the FTBFR group. However, the levels of irisin were not statistically changed following interventions (p = 0.561).

Conclusion

The findings showed that FT was effective in increasing circulating biomarkers involved in hypertrophy in older adults while adding BFR to FT had a slight increase in these biomarkers but had a tremendous increase in muscle strength.