Author Correction: Impaired cAMP-PKA-CREB1 signalling drives mitochondrial dysfunction in skeletal muscle during cancer cachexia.
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Published Erratum↗
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Results for “Skeletal muscle dysfunction”
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Exerkine dysregulation links visceral adiposity to skeletal muscle impairment in end-stage heart failure with reduced ejection fraction: proteomic evidence for a cardio-adipose-muscle axis.
BACKGROUND: Heart failure with reduced ejection fraction (HFrEF) is associated with profound alterations in body composition, skeletal muscle dysfunction, and impaired exercise capacity. Exerkines representing exercise-responsive signaling molecules released by skeletal muscle, adipose tissue, and other organs may mediate systemic metabolic communication between tissues. However, their role in advanced HFrEF and their relationship with adiposity and skeletal muscle characteristics remain poorly understood. METHODS: We studied 73 patients with end-stage HFrEF and 16 healthy controls. Body composition was assessed using computed tomography, including visceral (VAT), subcutaneous (SAT), and epicardial adipose tissue (EAT), as well as skeletal muscle quantity (psoas muscle index, PMI) and quality (psoas muscle density, PMD). Functional performance was evaluated using handgrip strength (HGT) and the 6-min walk test (6MWT). Circulating exerkines were quantified using the Olink technology. Associations between proteins and clinical variables were assessed using age- and creatinine-adjusted linear models with false discovery rate correction. RESULTS: Among patients with HFrEF, 36% were obese and 38% exhibited central obesity independent of BMI. Muscle strength and muscle quality were strongly associated with functional capacity. VAT correlated with muscle mass but not with muscle quality or performance. Compared with controls, HFrEF patients demonstrated elevated inflammatory and metabolic stress-related exerkines including CXCL8, CCL2, IL-6, TNF, IL-15, GDF15, FGF21, ANGPTL4, CTSB, DCN, and resistin. In contrast, proteins associated with muscle integrity and regenerative signaling (myostatin, BDNF, IL-7, SPARC) were significantly reduced. In HFrEF patients leptin strongly correlated with adiposity measures. Metabolic stress mediators (GDF15, IL-15, FGF21, CTSB) were inversely associated with muscle quality and functional performance, whereas myostatin positively correlated with muscle quality, strength, and exercise capacity. BDNF was inversely associated with frailty. CONCLUSIONS: Advanced HFrEF is characterized by a dysregulated exerkine network linking adiposity, skeletal muscle quality, and functional performance. Four biologically coherent axes were identified: a leptin-driven adiposity axis, a metabolic stress-muscle quality axis, a myostatin-related muscle function axis, and a neurotrophic frailty axis. These findings support the presence of a systemic cardio-adipose-muscle signaling network in end-stage HFrEF and identify candidate molecular mediators of sarcopenia and functional decline.
Humans↗
Age-induced changes in skeletal muscle mitochondrial DNA synthesis, quantity, and quality in genetically unique rats.
Mitochondrial genomic integrity is a key element of physiological processes and health. Changes in the half-life of the mitochondrial genome are implicated in the generation and accumulation of age-induced mitochondrial DNA (mtDNA) mutations, which are implicated in skeletal muscle aging and sarcopenia. There are conflicting data on the half-life of mtDNA, and there is limited information on how aging affects half-life in skeletal muscle. We hypothesized that skeletal muscle mtDNA synthesis rates would decrease with age in both female and male rats concomitant with changes in mtDNA integrity reflected in mtDNA copy number and mutation frequency. We measured mitochondrial genome half-life using stable isotope labeling over a period of 14 days and assessed mtDNA copy number and deletion mutation frequency using digital PCR in the quadriceps muscle of 9-month-old and 26-month-old male and female OKC-HET rats. We found a significant age-related increase in mtDNA half-life, from 132 days at 9 months to 216 days at 26 months of age in OKC-HET quadriceps. Concomitant with the increase in mtDNA half-life, we found an age-related increase in mtDNA deletion mutation frequency in both male and female rats. Notably, 26-month-old female rats had a lower mutation frequency than male rats, and there were no changes in mtDNA copy number with sex, age, or mitochondrial genotype. These data reveal several key findings: (1) mtDNA turnover in rat skeletal muscle decreases with age, (2) mtDNA half-lives in skeletal muscle are approximately an order of magnitude longer than what is reported for other tissues, and (3) muscle mtDNA turnover differs significantly from the turnover of other mitochondrial macromolecules including components of the mitochondrial nucleoid. These findings provide insight into the factors driving age-induced mtDNA mutation accumulation, which contribute to losses of mitochondrial genomic integrity and may play a role in skeletal muscle dysfunction.
Animals↗
Celery seed extract attenuates sarcopenic obesity and age-related sarcopenia by reducing intramuscular lipid accumulation in mice.
BACKGROUND & AIMS: Sarcopenia is characterized by progressive loss of skeletal muscle mass and function and is increasingly recognized to be influenced by metabolic disturbances associated with aging and obesity. Intramuscular lipid accumulation has emerged as a key pathological feature linking metabolic dysfunction to skeletal muscle deterioration. Celery seed extract (CSE) possesses anti-obesity, anti-inflammatory, and antioxidant properties; however, its potential role in skeletal muscle metabolism has not been well investigated. This study aimed to determine whether CSE attenuates skeletal muscle deterioration associated with obesity and aging through modulation of intramuscular lipid accumulation and related metabolic pathways. METHODS: Diet-induced obese mice and naturally aged mice were used to evaluate the effects of CSE supplementation. Skeletal muscle mass, grip strength, muscle morphology, intramuscular lipid content, mitochondrial metabolic signaling, inflammatory responses, and muscle protein turnover pathways were assessed using biochemical, molecular, and histological analyses. RESULTS: CSE supplementation significantly improved skeletal muscle mass, grip strength, and muscle fiber cross-sectional area in both obese and aged mice. These improvements were accompanied by reduced intramuscular triglyceride and cholesterol accumulation. Mechanistically, CSE improved mitochondrial metabolic signaling by activating the AMPK-PGC-1α pathway and increasing mitochondrial oxidative phosphorylation proteins. In addition, CSE suppressed inflammatory signaling pathways, including MAPK activation and NLRP3 inflammasome signaling, and improved muscle proteostasis by enhancing myogenic regulators while reducing the expression of proteolytic factors such as MuRF1, Atrogin-1, and myostatin. Correlation analyses further indicated that intramuscular lipid accumulation was closely associated with mitochondrial dysfunction, inflammatory activation, and muscle atrophy. CONCLUSIONS: These findings demonstrate that CSE alleviates skeletal muscle deterioration in both obesity- and aging-associated sarcopenia by reducing intramuscular lipid accumulation and improving mitochondrial metabolism, inflammatory responses, and muscle protein turnover. Targeting intramuscular lipid accumulation may therefore represent a promising nutritional strategy for preventing sarcopenia associated with metabolic and aging-related stress.
AMPK–PGC-1α↗
Neonatal gene therapy with AAV2/8-LSPhGAA improves hypertrophic cardiomyopathy in the Gaac.1826dupA knock-in murine model.
Pompe disease (PD) results from lysosomal acid α-glucosidase (GAA) deficiency, causing lysosomal glycogen accumulation in cardiac and skeletal muscles. We previously characterized a murine model carrying the orthologous human infantile-onset PD (IOPD) pathogenic variant, c.1826dupA (p.Y609*), introduced into the mouse Gaa gene. Compared to wild-type (WT; C57BL/6NJ) controls, Gaac.1826dupA mice exhibit reduced GAA activity and develop early-onset hypertrophic cardiomyopathy-evidenced by increased left ventricular wall thickness and left ventricular mass index (LVMI)- as well as impaired grip strength and gait abnormalities. To benchmark the model's disease fidelity and assess its responsiveness to established therapeutic intervention, Gaac.1826dupA mice received a single retro-orbital dose of AAV2/8-LSPhGAA (2 × 109 vg/g body weight) at postnatal day 12-14. Twelve weeks post-treatment, mice exhibited supraphysiological GAA enzymatic activity in the heart (550% of WT) and liver (400% of WT) with a 93% reduction in cardiac glycogen. No sex-dependent differences in therapeutic efficacy were observed. Echocardiography revealed robust reversal of cardiac pathology, with wall thicknesses and LVMI values approaching WT levels. In contrast to this profound cardiac rescue, skeletal muscle improvements were modest; while forelimb grip strength remained unchanged, automated gait analysis showed benefit limited to hind paw base of support. These findings demonstrate that the Gaac.1826dupA model mirrors the critical cardiomyopathy characteristic of IOPD. While systemic AAV treatment yields definitive cardiac correction, the partial skeletal muscle response highlights a clear need for optimization. Consequently, the Gaac.1826dupA mouse serves as a high-fidelity platform for evaluating next-generation genomic correction strategies targeting both cardiac and refractory neuromuscular manifestations of PD.
Acid α-glucosidase↗
Treatment updates in myotonic disorders.
Myotonia is delayed muscle relaxation after forceful contraction. It is due to hyperexcitability of the skeletal muscle membrane. It can arise from primary skeletal muscle ion channel dysfunction, involving chloride or sodium channels, but is also a prominent clinical feature in myotonic dystrophies where altered RNA splicing leads to secondary ion channel dysregulation amongst other systemic manifestations. Clinically, myotonia can range from delayed eye opening to a disabling symptom causing impaired mobility, functional difficulty and sometimes pain. It can also be a "hidden disability" with many patients feeling socially embarrassed by "looking healthy", yet being unable to do everyday physical tasks or to do them as effortlessly as their peers. It is a symptom that almost always indicates a genetic diagnosis, although it can occur in acquired conditions, including metabolic and drug-induced causes. To experience myotonia without knowing what it is can be baffling. To receive a genetic diagnosis associated with it can be life changing. Although there is no cure, there are many effective and available symptomatic treatments for myotonia and currently we are in an exciting era of clinical trials for new molecular disease-modifying therapies for myotonic dystrophy type 1. In this review, we consider recent developments in the treatment of myotonic disorders and how they may change clinical practice.
Humans↗
Perspective on Adeno-Associated Virus Capsid Modification for Duchenne Muscular Dystrophy Gene Therapy.
Duchenne muscular dystrophy (DMD) is a X-linked, progressive childhood myopathy caused by mutations in the dystrophin gene, one of the largest genes in the genome. It is characterized by skeletal and cardiac muscle degeneration and dysfunction leading to cardiac and/or respiratory failure. Adeno-associated virus (AAV) is a highly promising gene therapy vector. AAV gene therapy has resulted in unprecedented clinical success for treating several inherited diseases. However, AAV gene therapy for DMD remains a significant challenge. Hurdles for AAV-mediated DMD gene therapy include the difficulty to package the full-length dystrophin coding sequence in an AAV vector, the necessity for whole-body gene delivery, the immune response to dystrophin and AAV capsid, and the species-specific barriers to translate from animal models to human patients. Capsid engineering aims at improving viral vector properties by rational design and/or forced evolution. In this review, we discuss how to use the state-of-the-art AAV capsid engineering technologies to overcome hurdles in AAV-based DMD gene therapy.
Animals↗
Delivery of recombinant adeno-associated virus vectors to rat diaphragm muscle via direct intramuscular injection.
The diaphragm is the most important inspiratory muscle in all mammals, and ventilatory insufficiency caused by diaphragm dysfunction is the leading cause of morbidity and mortality in many genetic and acquired diseases affecting skeletal muscle. Currently, pharmacological inhibitors, genetically modified animals, and invasive procedures are used to study disorders affecting the diaphragm. However, these methodologies can be problematic because of off-target drug effects and the possible nonphysiological consequences of lifelong genetic alterations. Therefore, alternative methods to study this important respiratory muscle are needed. To resolve this, we have developed a methodology to deliver recombinant adeno-associated virus (rAAV) vectors to the rat diaphragm via direct intramuscular injection. We hypothesized that by direct injection of rAAV into the muscle we can selectively target the diaphragm and establish a novel experimental method for studying signaling pathways and also provide a strategy for effectively using rAAV to protect the diaphragm against disease. This report describes the methods and evidence to support the use of rAAV as a therapeutic intervention to study rat diaphragm biology during conditions that promote diaphragm dysfunction.
Animals↗
Premeal insulin administration lowers postprandial blood glucose and increases myocardial microvascular blood flow in people with type 1 diabetes: a randomised, crossover clinical trial.
AIMS/HYPOTHESIS: We aimed to evaluate whether prandial insulin timing affects vascular function in people with type 1 diabetes. Our hypothesis was that premeal insulin administration would lead to greater myocardial microvascular blood flow (MBF) via blunting postprandial hyperglycaemia. METHODS: People with type 1 diabetes between 18 and 35 years of age with BMI <30 kg/m2 underwent two protocols with a 1:1 randomised crossover design wherein prandial insulin was injected either 15 min before or 15 min after meal intake began. To provide a physiological comparison, age-, sex- and BMI-matched control participants completed one study where they consumed the same meal but received no exogenous insulin. Glucose, insulin, vascular function (including ultrasound measures of myocardial and skeletal muscle microvascular perfusion, aortic stiffness, brachial artery endothelial function) and biomarkers of systemic inflammation and endothelial dysfunction were assessed at baseline and then 2 h after meal ingestion within each protocol. The primary outcome was change in myocardial MBF within each protocol. Study personnel assessing outcomes were masked to group assignment. RESULTS: Eighteen people with type 1 diabetes and 18 matched control participants were analysed within each protocol. Glucose area under the curve was significantly greater (p=0.015) in the postmeal insulin study compared with the premeal insulin study in participants with type 1 diabetes. Myocardial microvascular flow velocity significantly increased (p=0.031) with premeal insulin administration in people with type 1 diabetes and this consequently led to greater myocardial MBF (p=0.044). There were no changes in myocardial MBF within the other protocols. Changes in vital signs were similar between all protocols. CONCLUSIONS/INTERPRETATION: Appropriately timed premeal insulin led to lower postprandial blood glucose along with increased myocardial MBF in people with type 1 diabetes. Further work is needed to determine the underlying aetiology of these changes. TRIAL REGISTRATION: ClinicalTrials.gov NCT04730882.
Humans↗
Integrated Multiomics Analyses of the Molecular Landscape of Sarcopenia in Alcohol-Related Liver Disease.
BACKGROUND: Skeletal muscle is a major target for ethanol-induced perturbations, leading to sarcopenia in alcohol-related liver disease (ALD). The complex interactions and pathways involved in adaptive and maladaptive responses to ethanol in skeletal muscle are not well understood. Unlike hypothesis-driven experiments, an integrated multiomics-experimental validation approach provides a comprehensive view of these interactions. METHODS: We performed multiomics analyses with experimental validation to identify novel regulatory mechanisms of sarcopenia in ALD. Studies were done in a comprehensive array of models including ethanol-treated (ET) murine and human-induced pluripotent stem cell-derived myotubes (hiPSCm), skeletal muscle from a mouse model of ALD (mALD) and human patients with alcohol-related cirrhosis and controls. We generated 13 untargeted datasets, including chromatin accessibility (assay for transposase accessible chromatin), RNA sequencing, proteomics, phosphoproteomics, acetylomics and metabolomics, and conducted integrated multiomics analyses using UpSet plots and feature extraction. Key findings were validated using immunoblots, redox measurements (NAD+/NADH ratio), imaging and senescence-associated molecular phenotype (SAMP) assays. Mechanistic studies included mitochondrial-targeted Lactobacillus brevis NADH oxidase (MitoLbNOX) to increase redox ratio and MitoTempo as a mitochondrial free radical scavenger. RESULTS: Multiomics analyses revealed enrichment in mitochondrial oxidative function, protein synthesis and senescence pathways consistent with the known effects of hypoxia-inducible factor 1α (HIF1α) during normoxia. Across preclinical and clinical models, HIF1α targets (n = 32 genes) and signalling genes (n > 100 genes) (n = 3 ATACseq, n = 65 phosphoproteomics, n = 10 acetylomics, n = 6 C2C12 proteomics, n = 106 C2C12 RNAseq, n = 64 hiPSC RNAseq, n = 30 hiPSC proteomics, n = 3 mouse proteomics, n = 25 mouse RNAseq, n = 8 human RNAseq, n = 3 human proteomics) were increased. Stabilization of HIF1α (C2C12, 6hEtOH 0.24 ± 0.09; p = 0.043; mALD 0.32 ± 0.074; p = 0.005; data shown as mean difference ± standard error mean) was accompanied by enrichment in the early transient and late change clusters, -log(p-value) = 1.5-3.8, of the HIF1α signalling pathway. Redox ratio was reduced in ET myotubes (C2C12: 15512 ± 872.1, p < 0.001) and mALD muscle, with decreased expression of electron transport chain components (CI-V, p < 0.05) and Sirt3 (C2C12: 0.067 ± 0.023, p = 0.025; mALD: 0.41 ± 0.12, p = 0.013). Acetylation of mitochondrial proteins was increased in both models (C2C12: 107364 ± 4558, p = 0.03; mALD: 40036 ± 18 987, p = 0.049). Ethanol-induced SAMP was observed across models (P16: C2C12: 0.2845 ± 0.1145, p < 0.05; hiPSCm: 0.2591, p = 0.041). MitoLbNOX treatment reversed redox imbalance, HIF1α stabilization, global acetylation and myostatin expression (p < 0.05). CONCLUSIONS: An integrated multiomics approach, combined with experimental validation, identifies HIF1α stabilization and accelerated post-mitotic senescence as novel mechanisms of sarcopenia in ALD. These findings show the complex molecular interactions leading to mitochondrial dysfunction and progressive sarcopenia in ALD.
Sarcopenia↗
PIEZO1 Mediates Myoblast Proliferation Under Simulated Microgravity.
Skeletal muscle atrophy is a major health risk of prolonged spaceflight, yet how microgravity reshapes muscle cells through mechanotransduction remains poorly understood. Here, we examined the mechanosensitive cation channel PIEZO1 in myoblast proliferation under simulated microgravity. Using a two-dimensional clinostat combined with Hi-C-based 3D genomics, transcriptomics, and functional assays, we found that simulated microgravity promotes C2C12 myoblast proliferation and upregulates Piezo1. Piezo1 mRNA knockdown reduced both proliferation and depolarization-induced Ca2 + influx, each partially restored under simulated microgravity, consistent with PIEZO1 being a central mediator of the response. Simulated microgravity also drove extensive 3D genome reorganization alongside changes in proliferation-related gene expression. Integrating chromatin architecture with transcriptomics, we found that PIEZO1 inhibition increased Elavl2 mRNA expression, PIEZO1 activation suppressed Elavl2 mRNA expression, and Elavl2 mRNA knockdown enhanced cell proliferation. These findings define a PIEZO1-ELAVL2 mechanotransduction axis, coupled to 3D chromatin remodeling, that regulates myoblast proliferation under simulated microgravity, and thus may be a target for countering spaceflight-associated muscle dysfunction.
Cell Proliferation↗
COVID-19 multi-omics reveal organ-specific responses and biomarkers.
OBJECTIVE: Post-COVID-19 syndrome is characterised by persistent immune dysfunction and multi-organ sequelae. This study aimed to characterise the systemic blood molecular landscape induced by SARS-CoV-2 infection and identify prognostic markers linked to skeletal muscle mass loss, a key driver of poor outcomes. METHODS: We enrolled 30 healthy controls and 307 COVID-19 patients, collecting 422 plasma samples for integrated proteomic and metabolomic profiling to investigate organ-specific molecular alterations in COVID-19. RESULTS: We comprehensively mapped the molecular landscape of COVID-19, encompassing immune, tissue-specific, and metabolic perturbations, and delineated their interactions. Focusing on organ-damage-related molecular patterns associated with disease progression and mortality, we found that skeletal muscle mass loss contributed to poor clinical outcomes of COVID-19 (p < 0.0001). Dysregulated arginine metabolism emerged as a key metabolic signature in fatal COVID-19 cases, with GLUL, GOT1, and citrulline showing significant correlation with skeletal muscle mass loss. Longitudinal analyses further revealed that reduced citrulline levels underlie the poor outcome of COVID-19 patients with muscle mass loss. These findings were robustly supported through multiple approaches: Mendelian randomization confirmed causal relationships between citrulline depletion, sarcopenia/fat-free mass loss, and COVID-19 mortality (p < 0.05), transcriptomic analyses of SARS-CoV-2-infected golden hamsters (GSE231910) provided additional support in enrichment of arginine biosynthesis (FDR < 0.05), and in vitro experiments further demonstrated that citrulline depletion promotes pro-inflammatory M1 macrophage polarisation — a key immunological feature of critical COVID-19. Leveraging these insights, we developed a skeletal muscle loss-specific prognostic prediction model for COVID-19 using GLUL, GOT1, and citrulline. This model effectively stratified patients into high- and low-risk groups (p = 0.035). CONCLUSION: Our study advances the understanding of COVID-19-induced organ pathophysiology and provides a foundation for developing targeted therapeutic strategies for post-COVID sequelae.
COVID-19↗
Proteins as Regulators of Metabolic Changes in Sepsis: Alterations in Body Fluids, Immune Cells, and Organs through the Eyes of Proteomics.
Sepsis is a life-threatening syndrome characterized by a dysregulated host response to infection and profound metabolic alterations that contribute to immune dysfunction and organ failure. This Review synthesizes proteomic evidence on sepsis-associated alterations in proteins involved in metabolic pathways across circulating biofluids, immune cells, and organs. Across plasma and urine, proteomic studies identify disturbances in lipoprotein-associated pathways, redox homeostasis, mitochondrial function, and substrate metabolism, indicating that protein signatures of metabolic dysregulation are systemic and detectable across biofluids. In immune cells, monocytes and neutrophils, proteomic analyses reveal a shift toward glycolysis with concurrent impairment of mitochondrial pathways alongside phenotype-dependent differences in lipid and redox-related programs. Organ-level studies further show that metabolic responses are heterogeneous, with distinct trajectories in the kidney, heart, liver, lung, skeletal muscle, and brain. These observations support the concept that sepsis involves compartment-specific remodeling of metabolism-associated protein networks rather than a single convergent metabolic state. Proteomics also highlights potential translational opportunities by identifying metabolism-associated proteins linked to disease severity, clinical phenotypes, and biologically distinct patient subgroups, although the current evidence remains largely exploratory and context-dependent. Overall, proteomics provides a complementary framework for understanding the molecular regulation of sepsis-associated metabolic dysfunction and may refine biological stratification and therapeutic targeting, particularly when integrated with longitudinal sampling and multiomic data.
Humans↗
Impaired stem cell migration and divisions in Duchenne muscular dystrophy revealed by live imaging.
Dysregulation of stem cell properties is a hallmark of many pathologies, but the dynamic behaviour of stem cells in their microenvironment during disease progression remains poorly understood. Using the mdx mouse model of Duchenne Muscular Dystrophy, we developed innovative live imaging of muscle stem cells (MuSCs) in vivo, and ex vivo on isolated myofibres. We show that mdx MuSCs have impaired migration and precocious differentiation through unbalanced symmetric divisions, driven by p38 and PI3K signalling pathways, in contrast to the p38-only dependence of healthy MuSCs. Cross-grafting shows that MuSC fate decisions are governed by fibre-independent cues, whereas their migration behaviour is determined by the myofibre niche. This study provides the first dynamic analysis of dystrophic MuSC properties in vivo, reconciling conflicting reports on their function. Our findings establish DMD as a MuSC disease with niche dysfunctions, offering strategies to restore stem cell functions for improved muscle regeneration.
Stem Cells↗
The effect of low birth weight as an intrauterine exposure on the early onset of sarcopenia through possible molecular pathways.
Sarcopenia, a musculoskeletal disease characterized by the progressive loss of skeletal muscle mass, strength, and physical performance, presents significant challenges to global public health due to its adverse effects on mobility, morbidity, mortality, and healthcare costs. This comprehensive review explores the intricate connections between sarcopenia and low birth weight (LBW), emphasizing the developmental origins of health and disease (DOHaD) hypothesis, inflammatory processes (inflammaging), mitochondrial dysfunction, circadian rhythm disruptions, epigenetic mechanisms, and genetic variations revealed through genome-wide studies (GWAS). A systematic search strategy was developed using PubMed to identify relevant English-language publications on sarcopenia, LBW, DOHaD, inflammaging, mitochondrial dysfunction, circadian disruption, epigenetic mechanisms, and GWAS. The publications consist of 46.2% reviews, 21.2% cohort studies, 4.8% systematic reviews, 1.9% cross-sectional studies, 13.4% animal studies, 4.8% genome-wide studies, 5.8% epigenome-wide studies, and 1.9% book chapters. The review identified key factors contributing to sarcopenia development, including the DOHaD hypothesis, LBW impact on muscle mass, inflammaging, mitochondrial dysfunction, the influence of clock genes, the role of epigenetic mechanisms, and genetic variations revealed through GWAS. The DOHaD theory suggests that LBW induces epigenetic alterations during foetal development, impacting long-term health outcomes, including the early onset of sarcopenia. LBW correlates with reduced muscle mass, grip strength, and lean body mass in adulthood, increasing the risk of sarcopenia. Chronic inflammation (inflammaging) and mitochondrial dysfunction contribute to sarcopenia, with LBW linked to increased oxidative stress and dysfunction. Disrupted circadian rhythms, regulated by genes such as BMAL1 and CLOCK, are associated with both LBW and sarcopenia, impacting lipid metabolism, muscle mass, and the ageing process. Early-life exposures, including LBW, induce epigenetic modifications like DNA methylation (DNAm) and histone changes, playing a pivotal role in sarcopenia development. Genome-wide studies have identified candidate genes and variants associated with lean body mass, muscle weakness, and sarcopenia, providing insights into genetic factors contributing to the disorder. LBW emerges as a potential early predictor of sarcopenia development, reflecting the impact of intrauterine exposures on long-term health outcomes. Understanding the complex interplay between LBW with inflammaging, mitochondrial dysfunction, circadian disruption, and epigenetic factors is essential for elucidating the pathogenesis of sarcopenia and developing targeted interventions. Future research on GWAS and the underlying mechanisms of LBW-associated sarcopenia is warranted to inform preventive strategies and improve public health outcomes.
Humans↗
Efficacy and Safety of Bimagrumab in Adults With Obesity and Metabolic Dysfunction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
AIMS: This study aims to systematically evaluate the efficacy of bimagrumab on body composition and glucose parameters in adults with obesity and metabolic dysfunction and its safety profile. METHODS: We searched MEDLINE, PubMed, Embase, and the Cochrane Library on April 20, 2026, for randomized controlled trials (RCTs) assessing bimagrumab treatment in adults with obesity, insulin resistance, or type 2 diabetes mellitus (T2DM). The risk of bias was assessed using the Cochrane Risk of Bias tool (RoB 2), and meta-analyses of efficacy and safety data were conducted using R software. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system was used to assess the strength of evidence. The study was registered with PROSPERO (CRD420261377110). RESULTS: Of the 134 retrieved records, 4 RCTs (enrolling 268 participants) were included. The included population represented a broad spectrum of metabolic dysfunction, from obesity and nondiabetic insulin resistance to established T2DM. Compared with placebo, bimagrumab treatment significantly reduced total weight (mean difference [MD] -4.85 kg, 95% confidence interval [CI] -6.82 to -2.88), fat mass (-4.72 kg [-8.05 to -1.40]), and glycated haemoglobin (HbA1c) (-0.13% [-0.23 to -0.03]) and significantly increased total lean mass (1.66 kg [0.81 to 2.51]). However, bimagrumab led to an increase in low-density lipoprotein (LDL) concentrations of 0.47 mmol/L [0.03 to 0.91] and significantly increased incidences of discontinuation (risk ratio [RR] 5.75 [1.61 to 20.46]), muscle spasms (RR 10.44 [4.23 to 25.75]), and diarrhoea (RR 4.91 [2.38 to 10.11]). CONCLUSION: Bimagrumab effectively reversed adverse effects on body composition in obese individuals, resulting in significant fat reduction, increased skeletal muscle mass, and improved glycemic control, suggesting that bimagrumab is a promising new target for personalized metabolic therapy.
Humans↗
A mouse model of autosomal dominant spastic ataxia and myopathy caused by a mutation in Tuba4a.
Hereditary ataxias are a heterogeneous group of neurodegenerative disorders characterized by impaired balance and coordination, often due to cerebellar dysfunction. Despite advances in identifying genetic causes, animal models remain essential for dissecting underlying mechanisms and testing therapeutic strategies. Here we describe a mouse model of spastic ataxia and myopathy caused by a missense mutation in Tuba4a (n.A626C, p.Gln176Pro). In an ENU mutagenesis screen, a male C57BL/6 J mouse exhibiting muscle wasting and an intention tremor starting at approximately 4 weeks-of-age was identified. The male was bred by in vitro fertilization to BALB/cByJ oocyte donors. Genetic mapping determined dominant inheritance and localized the mutation to Chromosome 1. Genome sequencing revealed single nucleotide polymorphisms (SNPs) in serine threonine kinase 36 (Stk36Y1003N) and alpha-tubulin 4A (Tuba4aQ176P) in the mapping interval. These SNPs were CRISPR-engineered into C57BL/6 J mice, which confirmed the Tuba4aQ176P variant as the causative mutation. Mutant mice are normal at 3 weeks, except for decrement in muscle response following repetitive nerve stimulation. However, by 30 days these mice have overt ataxia, Purkinje neuron degeneration, and extensive skeletal muscle defects, which contribute to a decreased lifespan. Dominant TUBA4A mutations in humans are associated with spastic ataxia type 11 (SPAX11), congenital myopathy type 26 (CMYO26), and frontotemporal dementia/amyotrophic lateral sclerosis type 9 (FTDALS9). Our mice exhibit hallmark features of SPAX11 and CMYO26, but do not show motor neuron degeneration. This specificity makes this model a valuable tool for studying cell-type selective effects of TUBA4A mutations in neurodegeneration and myopathy.
Animals↗
Granulopoietic Dysregulation in a Patient-Tailored Mouse Model of Barth Syndrome.
Barth syndrome (BTHS) is an X-linked recessive disorder characterized by cardiomyopathy, skeletal muscle myopathy and fatigue, growth restriction, and neutropenia. Neutropenia increases the risk of life-threatening bacterial infections, a major cause of death in individuals with BTHS. Currently, there is no curative treatment for BTHS or associated neutropenia. The development of therapeutic strategies to correct BTHS-associated neutropenia has been hindered by a limited understanding of the underlying molecular mechanisms involved. BTHS is caused by a mutation in the Tafazzin gene encoding a transacylase required for the maturation of cardiolipin, an inner mitochondrial membrane phospholipid crucial for mitochondrial structure and function. We introduced a BTHS patient's point mutation (TAZD75H) into the mouse Tafazzin enzyme's critical acyltransferase site using CRISPR/Cas9-mediated genome editing, resulting in a patient-tailored point mutant knock-in BTHS model (TazD75H) that expresses a stable mutant TazD75H protein lacking transacylase activity. TazD75H mice were then used to investigate how loss of Tafazzin enzymatic activity impacts hematopoiesis. Male TazD75H mice exhibited impaired granulopoiesis and neutropenia secondary to impaired function of hematopoietic progenitors. Furthermore, they demonstrated age-dependent neutrophil maturation impairment reflecting the variable neutropenia observed in BTHS patients. Additionally, male TazD75H mice exhibit chronic lymphopenia that persists post TazD75H bone marrow transplantation. Mechanistically, the TAZD75H point mutation caused hematopoietic cell mitochondrial dysfunction in patient-derived immortalized TAZD75H lymphoblasts, increasing reactive oxygen species production and mitochondrial membrane depolarization. Likewise, Cyclosporine A treatment rescued these mitochondrial phenotypes in vitro, confirming TAZD75H mitochondrial dysfunction. Overall, our findings demonstrate that mitochondrial dysfunction secondary to TAFAZZIN loss of enzymatic function underlies BTHS-associated neutropenia and lymphopenia.
Animals↗