How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves...How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves in skeletal muscles in vivo,considering their active deformation behavior.Here,this important issue is addressed by combining experiments performed with an ultrafast ultrasound imaging system to track nonlinear shear waves(shear shock waves)in muscles in vivo and finite element analysis relying on a physically motivated constitutive model to study the effect of muscle activation level.Skeletal muscle was loaded with a deep muscle stimulator to generate shear shock waves(SSWs).The particle velocities,second and third harmonics,and group velocities of the SSWs in living muscles under both passive and active states were measured in vivo.Our experimental results reveal,for the first time,that muscle states have a pronounced effect on wave features;a low level of activation may facilitate the occurrence of both the second and third harmonics,whereas a high level of activation may inhibit the third harmonic.Finite element analysis was further carried out to quantitatively explore the effect of active muscle deformation behavior on the generation and propagation of SSWs.The simulation results at different muscle activation levels confirmed the experimental findings.The ability to reveal the effects of muscle state on the features of SSWs may be helpful in elucidating the unique dynamic deformation mechanism of living skeletal muscles,quantitatively characterizing diverse shock wave-based therapy instruments,and guiding the design of muscle-mimicking soft materials.展开更多
The effect and potential molecular mechanisms of berberine on gluconeogenesis in skeletal muscles and adipose tissues were investigated.After adaptive feeding for one week,8 rats were randomly selected as the normal g...The effect and potential molecular mechanisms of berberine on gluconeogenesis in skeletal muscles and adipose tissues were investigated.After adaptive feeding for one week,8 rats were randomly selected as the normal group and fed on a standard diet.The remaining 32 rats were fed on a high-fat diet and given an intravenous injection of streptozotocin(STZ)for 2 weeks to induce the diabetic models.The diabetic rat models were confirmed by oral glucose tolerance test(OGTT)and randomly divided into 4 groups(n=8 each),which were all fed on a high-fat diet.Berberine(3 g/kg per day)or metformin(183 mg/kg per day)was intragastrically administered to the diabetic rats for 12 weeks,serving as berberine group and metformin group respectively.5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside[AICAR,an agonist of AMP-activated protein kinase(AMPK),0.5 mg/kg per day]was subcutaneously injected to the diabetic rats for 12 weeks,serving as AICAR group.The remaining 8 diabetic rats served as the model group,which was given a 0.5%carboxyl methylcellulose solution by oral gavage.Fasting serum insulin(FINS),OGTT as well as lipid parameters were tested by commercial kit.The protein levels of liver kinase B1(LKB1),AMPK,phosphorylated AMP-activated protein kinase(p-AMPK),transducer of regulated CREB activity 2(TORC2),phosphorylated transducer of regulated CREB activity 2(p-TORC2),phosphoenolpyruvate carboxykinase(PEPCK),and glucose-6-phosphatase(G6Pase)in skeletal muscles and adipose tissues were examined by Western blotting.The results showed that berberine significantly decreased the body weight,plasma glucose,insulin levels,and homeostatic model assessment for insulin resistance(HOMA-IR)of diabetic rats compared with those in the model group.Meanwhile,the serum total triglyceride(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)levels were markedly decreased and high-density lipoprotein cholesterol(HDL-C)level was significantly increased after the treatment with berberine.In addition,we found that berberine significantly increased the expression of p-AMPK and LKB1,while decreasing the p-TORC2 levels in skeletal muscles and adipose tissues.Moreover,the expression of PEPCK and G6Pase was significantly down-regulated after the treatment with berberine compared to the model group.It was suggested that the mechanism by which berberine inhibited peripheral tissue gluconeogenesis may be attributed to the activation of the LKB1-AMPK-TORC2 signaling pathway.展开更多
A synthetic isoflavone （ISO-S） or genistein was added in culture medium at different concentrations （0, 10, 20, 30, 40, and 80 p.mol L^-1） to investigate the effects of soybean isoflavones on antioxidative capacit...A synthetic isoflavone （ISO-S） or genistein was added in culture medium at different concentrations （0, 10, 20, 30, 40, and 80 p.mol L^-1） to investigate the effects of soybean isoflavones on antioxidative capacity of porcine skeletal muscle satellite cells. After 48 h incubation, the suspension was cryopreserved for the determination of superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GSH-Px） activities, and malondialdehyde （MDA） content. The mRNA levels of SOD, CAT, and GSH-Px gene in cells were detected with Taqman fluorescent probe method. The results showed that the content of MDA and the activities and the mRNA levels of SOD of porcine skeletal muscle satellite cells were influenced by supplemented soybean isoflavone （P〈0.05） when adding 10-80 μmol L^-1 ISO-S or genistein in the medium. The MDA contents, SOD and CAT activities and their mRNA expression levels of porcine skeletal muscle cells responded quadratically （P〈 0.05） as the level of ISO-S or genistein increased. Pre-incubation of porcine skeletal muscle satellite cells with ISO-S or genistein at 10-40 pmol L-1 elevated the activities and the mRNA expression levels of SOD and CAT in cells concurrently and decreased the cellular content of MDA （P〈 0.05）. The results indicated that pre-incubation of ISO-S or genistein at 10- 40μmol L^-1 could improve the antioxidative capacity of porcine skeletal muscle satellite cells.展开更多
Objective: To study on relationship of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in the injured local soft tissue with injured degrees of the soft tissue in the third lumbar vertebr...Objective: To study on relationship of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in the injured local soft tissue with injured degrees of the soft tissue in the third lumbar vertebrae (L3) transverse process syndrome model rat and to observe the effect of needle-knife therapy. Methods: One hundred and sixty male SD rats were randomly divided into normal group, model group, aminoguanidine (AG) group, needle-knife group, 40 rats in each group. The L3 transverse process syndrome rat model was established, and after treatment of needle-knife and AG, iNOS activities and NO contents and histomorpholocal changes in the soft tissues around L3 transverse process on 1, 3, 7 and 14 days were observed in the groups. Results: Compared with the normal group, iNOS activity and NO content in the model group were significantly increased (P<0.01); Compared with the model group, iNOS activities and NO contents were significantly decreased in both the needle-knife group and the AG group (both P<0.01); And both iNOS activities and NO contents were identical with both local inflammation response and injured degrees of the injured tissue in the groups. Conclusion: Needle-knife therapy can significantly inhibit generation of NO, alleviate inflammatory response and injured degree of the injured soft tissue, improve microcirculation, prevent formation of pathological scar tissue, and promote repair of the chronic soft tissue injury.展开更多
Calcineurin（Cn or CaN） is implicated in the control of skeletal muscle fiber phenotype and hypertrophy. However, little information is available concerning the expression of Cn in chickens. In the present study, the...Calcineurin（Cn or CaN） is implicated in the control of skeletal muscle fiber phenotype and hypertrophy. However, little information is available concerning the expression of Cn in chickens. In the present study, the expression of two Cn subunit genes（Cn Aα and Cn B1） was quantified by q PCR in the lateral gastrocnemius（LG, mainly composing of red fast-twitch myofibers）, the soleus（mainly composing of red slow-twitch myofibers） and the extensor digitorum longus（EDL, mainly composing of white fast-twitch myofibers） from Qingyuan partridge chickens（QY, slow-growing chicken breed） and Recessive White chickens（RW, fast-growing chicken breed） on different days（1, 8, 22, 36, 50 and 64 days post-hatching）. Although Cn Aα and Cn B1 gene expressions were variable with different trends in different skeletal muscles in the two chicken breeds during postnatal growth, it is highly muscle phenotype and breed specific. In general, the levels of Cn Aα and Cn B1 gene expressions of the soleus were lower than those of EDL and LG in both chicken breeds at the same stages. Compared between the two chicken breeds, the levels of Cn Aα gene expression of the three skeletal muscles in QY chickens were higher than those in RW chickens on days 1 and 22. However, on day 64, the levels of both Cn Aα and Cn B1 gene expressions of the three skeletal muscles were lower in QY chickens than those in RW chickens. Correlation analysis of the levels of Cn Aα and Cn B1 gene expressions of the same skeletal muscle showed that there were positive correlations for all three skeletal muscle tissues in two chicken breeds. These results provide some valuable clues to understand the role of Cn in the development of chicken skeletal muscles, with a function that may be related to meat quality.展开更多
Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol...Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Cell proliferation was assessed using a 5-bromo-2’-deoxyuridine(BrdU)assay kit.Western blot analysis was performed to determine the protein expressions of related factors.The effects of Catalpa bignonioides extract were investigated in mice using the treadmill exhaustion test and whole-limb grip strength assay.Chemical composition analysis was performed using high-performance liquid chromatography(HPLC).Results:Catalpa bignonioides extract increased the proliferation of C2C12 mouse myoblasts by activating the Akt/mTOR signaling pathway.It also induced metabolic changes,increasing the number of mitochondria and glucose metabolism by phosphorylating adenosine monophosphate-activated protein kinase.In an in vivo study,the extract-treated mice showed improved motor abilities,such as muscular endurance and grip strength.Additionally,HPLC analysis showed that vanillic acid may be the main component of the Catalpa bignonioides extract that enhanced muscle strength.Conclusions:Catalpa bignonioides improves exercise performance through regulation of growth and metabolism in skeletal muscles,suggesting its potential as an effective natural agent for improving muscular strength.展开更多
In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay be...In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay between skeletal muscle and endothelial cells in the vascularization ofmuscle tissue.By harnessing the capabilities of three-dimensional(3D)bioprinting and modeling,we developed a novel approach involving the co-construction of endothelial and muscle cells,followed by their subsequent differentiation.Our findings highlight the importance of the interaction dynamics between these two cell types.Notably,introducing endothelial cells during the advanced phases of muscle differentiation enhanced myotube assembly.Moreover,it stimulated the development of the vascular network,paving the way for the early stages of vascularized skeletal muscle development.The methodology proposed in this study indicates the potential for constructing large-scale,physiologically aligned skeletal muscle.Additionally,it highlights the need for exploring the delicate equilibrium and mutual interactions between muscle and endothelial cells.Based on the multicell-type interaction model,we can predict promising pathways for constructing even more intricate tissues or organs.展开更多
Objective:To explore the mechanism of the degradation of human hair keratin (HHK) scaffold material implanted in damaged skeletal muscle tissues. Methods: Six New Zealand rabbits with HHK scaffold material implants (c...Objective:To explore the mechanism of the degradation of human hair keratin (HHK) scaffold material implanted in damaged skeletal muscle tissues. Methods: Six New Zealand rabbits with HHK scaffold material implants (composed of 3 different types of HHK material with varied degradation speed) after musclectomy were divided into 3 groups (2 in each group) to observe the degradation of the material at 1, 3, 6weeks after operation. Another rabbit without operation was used as the control group. The degradation of HHK was observed with light microscopy, histochemistry of ubiquitin and electron microscopy. Results:Light microscopy showed that human hair cuticles fell off from the HHK material and emerged, and the macrophagocytes and multinucleate giant cells were attached onto the surface of the material, which became homogeneous at the first postoperative week. The HHK scaffold material was degraded into particles that was phagocytosed by macrophagocytes and multinucleate giant cells at the third week. Ubiquitin enzymatic histochemistry showed that the macrophagocytes and the multinucleate giant cells were positive at the first week. Under electron microscope, HHK scaffold material was degraded into particles, and at the sixth week,part of HHK scaffold material was further degraded. Conclusion: Large mass of the HHK scaffold material is degraded via ubiquitin system, and the resultant particles are phagocytosed and degraded with the cooperation of lysosome and ubiquitin.展开更多
Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using li...Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.展开更多
Objective： To study the mechanism of Tuina in the treatment of skeletal muscle injury. Methods： Rabbits were heavily beaten at gastrocnemius muscle to make acute contusion model and then treated respectively by earl...Objective： To study the mechanism of Tuina in the treatment of skeletal muscle injury. Methods： Rabbits were heavily beaten at gastrocnemius muscle to make acute contusion model and then treated respectively by early Tuina and routine Tuina. The number of satellite cells of skeletal muscles was observed. Results： The number of the satellite cells continued to grow in both groups, and it began to increase significantly 3-5 days after Tuina treatment. Early Tuina treatment produces larger number of satellite cells than routine Tuina treatment. Conclusion： Early Tuina treatment is helpful to the marked recovery of skeletal muscles by increasing the number of satellite cell.展开更多
The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metab...The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway.Twentyfour pregnant goats were assigned to the control group(100%of the nutrients requirement,n=12)and restricted group(60%of the control feed allowance from pregnant days 45 to 100,n=12).Blood and Longissimus thoracis muscle were sampled from dams(100 d of gestation),fetuses(100 d of gestation),and kids(90 d after birth)in each group.The data were analyzed using the linear MIXED model,with the multiple comparison method of SIDAK applied.Intake restriction reduced(P<0.05)the total blood protein of dams and fetuses.Maternal restriction decreased(P<0.05)the cAMP-responsive element-binding protein 1(CREB1),CREB-binding protein(CREBBP),protein kinase A(PKA),aryl hydrocarbon receptor nuclear translocator-like protein 1(BMAL1),protein kinase B(AKT1),mammalian target of rapamycin(mTOR),and regulatory-associated protein of mTOR(RPTOR)mRNA expression in the fetuses,and reduced(P<0.05)the CREBBP,nuclear receptor subfamily 1 group H member 3(NR1 H3),D-box binding PAR bZIP transcription factor(DBP)and PKA mRNA levels in the kids,but increased(P<0.05)the peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1 A)and tuberous sclerosis 2(TSC2)mRNA levels in the fetuses.The mRNA expression of clock circadian regulator(CLOCK)and TSC2 genes was increased(P<0.05)in the restricted kids.The protein expression of total PKA and phosphorylated PKA in the restricted fetuses and kids were downregulated(P<0.05),and the protein expression of total mTOR and phosphorylated mTOR were reduced(P<0.05)in the restricted fetuses and kids.Maternal intake restriction regulated fat oxidation,protein synthesis,and circadian clock expression in the muscles of the offspring probably via the glucagon-mediated PKA-CREB pathway,which reveals a noteworthy molecular pathway that maternal undernutrition leads to metabolic adaptation of skeletal muscle in offspring.展开更多
BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in the...BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in these patients.However,their actual prevalence and pathophysiology remain to be elucidated.AIM To determine the prevalence of SMAs and to assess the significance of circulating myokines as biomarkers in patients with MASLD.METHODS Skeletal muscle strength and muscle mass were measured in a cross-sectional study in a cohort of 62 patients fulfilling MASLD criteria,recruited from the outpatient clinics of a tertiary level hospital.The degree of fibrosis and liver steatosis was studied using abdominal ultrasound and transitional elastography.Anthropometric and metabolic characteristics as well as serum levels of different myokines were also determined in the MASLD cohort.Statistical analysis was performed comparing results according to liver fibrosis and steatosis.RESULTS No significant differences were found in both skeletal muscle strength and skeletal muscle mass in patients with MASLD between different stages of liver fibrosis.Interestingly,serum levels of fibroblast growth factor-21(FGF21)were significantly higher in patients with MASLD with advanced hepatic fibrosis(F3-F4)than in those with lower fibrosis stages(F0-F2)(197.49±198.27 pg/mL vs 95.62±83.67 pg/mL;P=0.049).In addition,patients with MASLD with severe hepatosteatosis(S3)exhibited significantly higher serum levels of irisin(1116.87±1161.86 pg/mL)than those with lower grades(S1-S2)(385.21±375.98 pg/mL;P=0.001).CONCLUSION SMAs were uncommon in the patients with MASLD studied.Higher serum levels of irisin and FGF21 were detected in patients with advanced liver steatosis and fibrosis,respectively,with potential implications as biomarkers.展开更多
Skeletal muscles are essential for locomotion,posture,and metabolic regulation.To understand physiological processes,exercise adaptation,and muscle-related disorders,it is critical to understand the molecular pathways...Skeletal muscles are essential for locomotion,posture,and metabolic regulation.To understand physiological processes,exercise adaptation,and muscle-related disorders,it is critical to understand the molecular pathways that underlie skeletal muscle function.The process of muscle contra ction,orchestrated by a complex interplay of molecular events,is at the core of skeletal muscle function.Muscle contraction is initiated by an action potential and neuromuscular transmission requiring a neuromuscular junction.Within muscle fibers,calcium ions play a critical role in mediating the interaction between actin and myosin filaments that generate force.Regulation of calcium release from the sarcoplasmic reticulum plays a key role in excitation-contraction coupling.The development and growth of skeletal muscle are regulated by a network of molecular pathways collectively known as myogenesis.Myogenic regulators coordinate the diffe rentiation of myoblasts into mature muscle fibers.Signaling pathways regulate muscle protein synthesis and hypertrophy in response to mechanical stimuli and nutrient availability.Seve ral muscle-related diseases,including congenital myasthenic disorders,sarcopenia,muscular dystrophies,and metabolic myopathies,are underpinned by dys regulated molecular pathways in skeletal muscle.Therapeutic interventions aimed at preserving muscle mass and function,enhancing regeneration,and improving metabolic health hold promise by targeting specific molecular pathways.Other molecular signaling pathways in skeletal muscle include the canonical Wnt signaling pathway,a critical regulator of myogenesis,muscle regeneration,and metabolic function,and the Hippo signaling pathway.In recent years,more details have been uncovered about the role of these two pathways during myogenesis and in developing and adult skeletal muscle fibers,and at the neuromuscular junction.In fact,research in the last few years now suggests that these two signaling pathways are interconnected and that they jointly control physiological and pathophysiological processes in muscle fibers.In this review,we will summarize and discuss the data on these two pathways,focusing on their concerted action next to their contribution to skeletal muscle biology.However,an in-depth discussion of the noncanonical Wnt pathway,the fibro/a dipogenic precursors,or the mechanosensory aspects of these pathways is not the focus of this review.展开更多
Sarcopenia,a progressive and systemic skeletal muscle disorder marked by the accelerated deterioration of both muscle function and mass,is highly prevalent among the elderly population,significantly contributing to an...Sarcopenia,a progressive and systemic skeletal muscle disorder marked by the accelerated deterioration of both muscle function and mass,is highly prevalent among the elderly population,significantly contributing to an elevated risk of adverse outcomes,including falls,fractures,and muscle weakness.Clinical investigations have identified a strong correlation between sarcopenia and several prevalent degenerative skeletal muscle disorders.This correlation is attributed to imbalances in joint mechanics resulting from localized muscle atrophy and the influence of musculoskeletal secretory factors.In this review,we discuss the broader implications of sarcopenia and critically evaluate the currently established assessment methods.Furthermore,the clinical significance of prevalent musculoskeletal disorders(including osteoporosis,osteoarthritis,and spinal pathologies)in relation to sarcopenia,alongside the underlying mechanisms influencing this relationship,is summarized.Additionally,the effects of sarcopenia on the therapeutic efficacy of medications and surgical interventions for musculoskeletal conditions are reviewed.Sarcopenia is intricately linked to the onset,progression,and prognosis of musculoskeletal disorders.Future research should prioritize elucidating the potential mechanisms that connect muscle loss with skeletal muscle diseases,and investigating whether mitigating sarcopenia symptoms could decelerate the progression of these disorders,thereby paving new pathways for therapeutic interventions.展开更多
Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow f...Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.展开更多
Skeletal muscle satellite cells are stem cells characterized by their multipotency and capacity for in vitro proliferation.However,primary skeletal muscle satellite cells demonstrate limited proliferative capacity in ...Skeletal muscle satellite cells are stem cells characterized by their multipotency and capacity for in vitro proliferation.However,primary skeletal muscle satellite cells demonstrate limited proliferative capacity in vitro,which impedes their investigation in poultry skeletal muscle research.Cell immortalization techniques have emerged as valuable tools to address this limitation and facilitate the study of skeletal muscle satellite cell functions.This study achieved the immortalization of chicken skeletal muscle satellite cells through the transduction of primary cells with TERT(telomerase reverse transcriptase)amplified from chicken(chTERT)using a lentiviral vector via telomerase activity reconstitution.While the cells successfully overcame replicative senescence,complete immortalization was not achieved.Initial functional characterization revealed that the proliferative properties and cell cycle characteristics of the immortalized chicken skeletal muscle satellite cell lines(ICMS)closely resembled those of chicken primary muscle satellite cells(CPMSCs).Serum dependency analysis and soft agar assays confirmed that ICMS did not undergo malignant transformation.Furthermore,induced differentiation experiments demonstrated preserved differentiation capacity in ICMS.The established cell lines provide a fundamental framework for developing immortalized poultry cell lines and offer a cellular model for investigating poultry skeletal muscle-related functional genes.展开更多
1.Exercise enhances muscle function and insulin sensitivity Skeletal muscle plays a fundamental role in not only locomotion,but also systemic metabolism.In people with type 2 diabetes,skeletal muscle is a major site o...1.Exercise enhances muscle function and insulin sensitivity Skeletal muscle plays a fundamental role in not only locomotion,but also systemic metabolism.In people with type 2 diabetes,skeletal muscle is a major site of insulin resistance,with impaired insulin signaling and reduced glucose transport activity contributing to metabolic dysfunction.展开更多
Metabolic dysfunction-associated steatotic liver disease is increasingly understood to be closely linked with skeletal muscle alterations,such as sarcopenia,myoste-atosis,and metabolic dysregulation,which play a key r...Metabolic dysfunction-associated steatotic liver disease is increasingly understood to be closely linked with skeletal muscle alterations,such as sarcopenia,myoste-atosis,and metabolic dysregulation,which play a key role in its pathogenesis and progression.Recent literature,including an article by Isakov,highlights the bidirectional interactions between muscle and liver,underscoring shared mechanisms such as insulin resistance,inflammation,and myokine imbalance.This letter reflects on key findings from the review,noting strengths such as its integration of mechanistic insights,discussion of emerging biomarkers,and emphasis on lifestyle and pharmacological interventions.It also identifies areas for further development,including standardization of diagnostic criteria and more rigorous evaluation of translational data.As muscle health gains promi-nence in metabolic dysfunction-associated steatotic liver disease research,multidisciplinary strategies that target both hepatic and muscular systems may offer more effective avenues for prevention and treatment.展开更多
BACKGROUND Metastasis of renal cell carcinoma(RCC)to the skeletal muscle and small bowel is an exceedingly rare occurrence.Both of these sites are unusual sites for RCC to metastasize to and to occur simultaneously is...BACKGROUND Metastasis of renal cell carcinoma(RCC)to the skeletal muscle and small bowel is an exceedingly rare occurrence.Both of these sites are unusual sites for RCC to metastasize to and to occur simultaneously is even less common.CASE SUMMARY A 58-year-old male with known history of RCC presented with a recurrence that was diagnosed through imaging and biopsies.Mucosa abnormalities of small bowel noted during endoscopy were biopsied as well as lesion in the psoas muscle that was noted.CONCLUSION This case report emphasizes that RCC can not only recur but can do so even decades later and present as metastatic foci at atypical sites.展开更多
BACKGROUND Improving our understanding of whether increased dietary intake ofω-3 polyunsaturated fatty acids(PUFAs)is beneficial for increasing skeletal muscle mass in patients with metabolic dysfunction-associated f...BACKGROUND Improving our understanding of whether increased dietary intake ofω-3 polyunsaturated fatty acids(PUFAs)is beneficial for increasing skeletal muscle mass in patients with metabolic dysfunction-associated fatty liver disease(MAFLD)could provide an important clinical evidence base for the development of relevant nutritional guidelines.AIM To investigate the effect of total dietaryω-3 PUFAs and their subtypes on skeletal muscle mass in MAFLD.METHODS This cross-sectional study involved 2316 participants from four National Health and Nutrition Examination Survey cycles between 2011 and 2018.Dietary intake ofω-3 PUFAs was collected through 24-hour dietary recall interviews.Appendicular skeletal muscle mass index(ASMI)was calculated by dividing ASM in kilograms by height squared.RESULTS The multiple linear regression model showed significant relationships for dietary intake of totalω-3 PUFAs with higher ASMI(β:0.06,95%CI:0.01-0.11)in MAFLD patients.Dietary a-linolenic acid(ALA)(β:0.06,95%CI:0.01-0.12),docosapentaenoic acid(β:1.28,95%CI:0.01-2.54),and docosahexaenoic acid(DHA)(β:0.19,95%CI:0.01-0.37)were significantly associated with higher ASMI,while intake of stearidonic acid and eicosapentaenoic acid did not improve ASMI.In patients with high probability of liver fibrosis,dietary intake of ALA was associated with higher ASMI(β:0.11,95%CI:0.03-0.18).Stratified analysis found that DHA was associated with higher ASMI in patients with obesity and higher metabolic risk.CONCLUSION Increasing dietary intake ofω-3 PUFAs improved skeletal muscle health in patients with MAFLD.Patient with obesity and higher metabolic risk were more likely to benefit from intake of DHA.展开更多
基金supported by the National Students Training Program for Innovation(Grant No.202210007029)。
文摘How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves in skeletal muscles in vivo,considering their active deformation behavior.Here,this important issue is addressed by combining experiments performed with an ultrafast ultrasound imaging system to track nonlinear shear waves(shear shock waves)in muscles in vivo and finite element analysis relying on a physically motivated constitutive model to study the effect of muscle activation level.Skeletal muscle was loaded with a deep muscle stimulator to generate shear shock waves(SSWs).The particle velocities,second and third harmonics,and group velocities of the SSWs in living muscles under both passive and active states were measured in vivo.Our experimental results reveal,for the first time,that muscle states have a pronounced effect on wave features;a low level of activation may facilitate the occurrence of both the second and third harmonics,whereas a high level of activation may inhibit the third harmonic.Finite element analysis was further carried out to quantitatively explore the effect of active muscle deformation behavior on the generation and propagation of SSWs.The simulation results at different muscle activation levels confirmed the experimental findings.The ability to reveal the effects of muscle state on the features of SSWs may be helpful in elucidating the unique dynamic deformation mechanism of living skeletal muscles,quantitatively characterizing diverse shock wave-based therapy instruments,and guiding the design of muscle-mimicking soft materials.
基金This project was supported by the National Natural Science Foundation of China(No.81673757 and No.81603652).
文摘The effect and potential molecular mechanisms of berberine on gluconeogenesis in skeletal muscles and adipose tissues were investigated.After adaptive feeding for one week,8 rats were randomly selected as the normal group and fed on a standard diet.The remaining 32 rats were fed on a high-fat diet and given an intravenous injection of streptozotocin(STZ)for 2 weeks to induce the diabetic models.The diabetic rat models were confirmed by oral glucose tolerance test(OGTT)and randomly divided into 4 groups(n=8 each),which were all fed on a high-fat diet.Berberine(3 g/kg per day)or metformin(183 mg/kg per day)was intragastrically administered to the diabetic rats for 12 weeks,serving as berberine group and metformin group respectively.5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside[AICAR,an agonist of AMP-activated protein kinase(AMPK),0.5 mg/kg per day]was subcutaneously injected to the diabetic rats for 12 weeks,serving as AICAR group.The remaining 8 diabetic rats served as the model group,which was given a 0.5%carboxyl methylcellulose solution by oral gavage.Fasting serum insulin(FINS),OGTT as well as lipid parameters were tested by commercial kit.The protein levels of liver kinase B1(LKB1),AMPK,phosphorylated AMP-activated protein kinase(p-AMPK),transducer of regulated CREB activity 2(TORC2),phosphorylated transducer of regulated CREB activity 2(p-TORC2),phosphoenolpyruvate carboxykinase(PEPCK),and glucose-6-phosphatase(G6Pase)in skeletal muscles and adipose tissues were examined by Western blotting.The results showed that berberine significantly decreased the body weight,plasma glucose,insulin levels,and homeostatic model assessment for insulin resistance(HOMA-IR)of diabetic rats compared with those in the model group.Meanwhile,the serum total triglyceride(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)levels were markedly decreased and high-density lipoprotein cholesterol(HDL-C)level was significantly increased after the treatment with berberine.In addition,we found that berberine significantly increased the expression of p-AMPK and LKB1,while decreasing the p-TORC2 levels in skeletal muscles and adipose tissues.Moreover,the expression of PEPCK and G6Pase was significantly down-regulated after the treatment with berberine compared to the model group.It was suggested that the mechanism by which berberine inhibited peripheral tissue gluconeogenesis may be attributed to the activation of the LKB1-AMPK-TORC2 signaling pathway.
基金supports of the grants from the Ministry of Science and Technology of China and the Department of Science and Tech-nology of Guangdong Province, Chinasupported by the National Basic Research Program of China (973 Program, 2004CB117500)the Earmarked Fund for Modern Agro-Industry Technology Research System, China
文摘A synthetic isoflavone （ISO-S） or genistein was added in culture medium at different concentrations （0, 10, 20, 30, 40, and 80 p.mol L^-1） to investigate the effects of soybean isoflavones on antioxidative capacity of porcine skeletal muscle satellite cells. After 48 h incubation, the suspension was cryopreserved for the determination of superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GSH-Px） activities, and malondialdehyde （MDA） content. The mRNA levels of SOD, CAT, and GSH-Px gene in cells were detected with Taqman fluorescent probe method. The results showed that the content of MDA and the activities and the mRNA levels of SOD of porcine skeletal muscle satellite cells were influenced by supplemented soybean isoflavone （P〈0.05） when adding 10-80 μmol L^-1 ISO-S or genistein in the medium. The MDA contents, SOD and CAT activities and their mRNA expression levels of porcine skeletal muscle cells responded quadratically （P〈 0.05） as the level of ISO-S or genistein increased. Pre-incubation of porcine skeletal muscle satellite cells with ISO-S or genistein at 10-40 pmol L-1 elevated the activities and the mRNA expression levels of SOD and CAT in cells concurrently and decreased the cellular content of MDA （P〈 0.05）. The results indicated that pre-incubation of ISO-S or genistein at 10- 40μmol L^-1 could improve the antioxidative capacity of porcine skeletal muscle satellite cells.
基金supported by a grant from National "973" Project (No: 2006CB504508)
文摘Objective: To study on relationship of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in the injured local soft tissue with injured degrees of the soft tissue in the third lumbar vertebrae (L3) transverse process syndrome model rat and to observe the effect of needle-knife therapy. Methods: One hundred and sixty male SD rats were randomly divided into normal group, model group, aminoguanidine (AG) group, needle-knife group, 40 rats in each group. The L3 transverse process syndrome rat model was established, and after treatment of needle-knife and AG, iNOS activities and NO contents and histomorpholocal changes in the soft tissues around L3 transverse process on 1, 3, 7 and 14 days were observed in the groups. Results: Compared with the normal group, iNOS activity and NO content in the model group were significantly increased (P<0.01); Compared with the model group, iNOS activities and NO contents were significantly decreased in both the needle-knife group and the AG group (both P<0.01); And both iNOS activities and NO contents were identical with both local inflammation response and injured degrees of the injured tissue in the groups. Conclusion: Needle-knife therapy can significantly inhibit generation of NO, alleviate inflammatory response and injured degree of the injured soft tissue, improve microcirculation, prevent formation of pathological scar tissue, and promote repair of the chronic soft tissue injury.
基金The National Natural Science Foundation of China (31301967)the Key Technology Support Program of Jiangsu Province, China (BK2012268)the Earmarked Fund for Modern Agro-Industry Technology Research System, China (CARS-42-G03) supported this research
文摘Calcineurin（Cn or CaN） is implicated in the control of skeletal muscle fiber phenotype and hypertrophy. However, little information is available concerning the expression of Cn in chickens. In the present study, the expression of two Cn subunit genes（Cn Aα and Cn B1） was quantified by q PCR in the lateral gastrocnemius（LG, mainly composing of red fast-twitch myofibers）, the soleus（mainly composing of red slow-twitch myofibers） and the extensor digitorum longus（EDL, mainly composing of white fast-twitch myofibers） from Qingyuan partridge chickens（QY, slow-growing chicken breed） and Recessive White chickens（RW, fast-growing chicken breed） on different days（1, 8, 22, 36, 50 and 64 days post-hatching）. Although Cn Aα and Cn B1 gene expressions were variable with different trends in different skeletal muscles in the two chicken breeds during postnatal growth, it is highly muscle phenotype and breed specific. In general, the levels of Cn Aα and Cn B1 gene expressions of the soleus were lower than those of EDL and LG in both chicken breeds at the same stages. Compared between the two chicken breeds, the levels of Cn Aα gene expression of the three skeletal muscles in QY chickens were higher than those in RW chickens on days 1 and 22. However, on day 64, the levels of both Cn Aα and Cn B1 gene expressions of the three skeletal muscles were lower in QY chickens than those in RW chickens. Correlation analysis of the levels of Cn Aα and Cn B1 gene expressions of the same skeletal muscle showed that there were positive correlations for all three skeletal muscle tissues in two chicken breeds. These results provide some valuable clues to understand the role of Cn in the development of chicken skeletal muscles, with a function that may be related to meat quality.
基金supported by Korea Environment Industry&Technology Institute through Project to make multi-ministerial national biological research resources more advanced Project,funded by Korea Ministry of Environment(grant number RS-2023-00230403).
文摘Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Cell proliferation was assessed using a 5-bromo-2’-deoxyuridine(BrdU)assay kit.Western blot analysis was performed to determine the protein expressions of related factors.The effects of Catalpa bignonioides extract were investigated in mice using the treadmill exhaustion test and whole-limb grip strength assay.Chemical composition analysis was performed using high-performance liquid chromatography(HPLC).Results:Catalpa bignonioides extract increased the proliferation of C2C12 mouse myoblasts by activating the Akt/mTOR signaling pathway.It also induced metabolic changes,increasing the number of mitochondria and glucose metabolism by phosphorylating adenosine monophosphate-activated protein kinase.In an in vivo study,the extract-treated mice showed improved motor abilities,such as muscular endurance and grip strength.Additionally,HPLC analysis showed that vanillic acid may be the main component of the Catalpa bignonioides extract that enhanced muscle strength.Conclusions:Catalpa bignonioides improves exercise performance through regulation of growth and metabolism in skeletal muscles,suggesting its potential as an effective natural agent for improving muscular strength.
基金support from the National Natural Science Foundation of China(Nos.T2222029,U21A20396,and 62127811)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(No.XDA16020802)the CAS Project for Young Scientists in Basic Research(No.YSBR-012).
文摘In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay between skeletal muscle and endothelial cells in the vascularization ofmuscle tissue.By harnessing the capabilities of three-dimensional(3D)bioprinting and modeling,we developed a novel approach involving the co-construction of endothelial and muscle cells,followed by their subsequent differentiation.Our findings highlight the importance of the interaction dynamics between these two cell types.Notably,introducing endothelial cells during the advanced phases of muscle differentiation enhanced myotube assembly.Moreover,it stimulated the development of the vascular network,paving the way for the early stages of vascularized skeletal muscle development.The methodology proposed in this study indicates the potential for constructing large-scale,physiologically aligned skeletal muscle.Additionally,it highlights the need for exploring the delicate equilibrium and mutual interactions between muscle and endothelial cells.Based on the multicell-type interaction model,we can predict promising pathways for constructing even more intricate tissues or organs.
文摘Objective:To explore the mechanism of the degradation of human hair keratin (HHK) scaffold material implanted in damaged skeletal muscle tissues. Methods: Six New Zealand rabbits with HHK scaffold material implants (composed of 3 different types of HHK material with varied degradation speed) after musclectomy were divided into 3 groups (2 in each group) to observe the degradation of the material at 1, 3, 6weeks after operation. Another rabbit without operation was used as the control group. The degradation of HHK was observed with light microscopy, histochemistry of ubiquitin and electron microscopy. Results:Light microscopy showed that human hair cuticles fell off from the HHK material and emerged, and the macrophagocytes and multinucleate giant cells were attached onto the surface of the material, which became homogeneous at the first postoperative week. The HHK scaffold material was degraded into particles that was phagocytosed by macrophagocytes and multinucleate giant cells at the third week. Ubiquitin enzymatic histochemistry showed that the macrophagocytes and the multinucleate giant cells were positive at the first week. Under electron microscope, HHK scaffold material was degraded into particles, and at the sixth week,part of HHK scaffold material was further degraded. Conclusion: Large mass of the HHK scaffold material is degraded via ubiquitin system, and the resultant particles are phagocytosed and degraded with the cooperation of lysosome and ubiquitin.
基金supported by the National Natural Science Foundation of China(No.52475067).
文摘Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.
文摘Objective： To study the mechanism of Tuina in the treatment of skeletal muscle injury. Methods： Rabbits were heavily beaten at gastrocnemius muscle to make acute contusion model and then treated respectively by early Tuina and routine Tuina. The number of satellite cells of skeletal muscles was observed. Results： The number of the satellite cells continued to grow in both groups, and it began to increase significantly 3-5 days after Tuina treatment. Early Tuina treatment produces larger number of satellite cells than routine Tuina treatment. Conclusion： Early Tuina treatment is helpful to the marked recovery of skeletal muscles by increasing the number of satellite cell.
基金supported by the National Natural Science Foundation of China[31730092,31760678 and 31402105]Hunan innovative Province construction project[2019RS3021]。
文摘The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway.Twentyfour pregnant goats were assigned to the control group(100%of the nutrients requirement,n=12)and restricted group(60%of the control feed allowance from pregnant days 45 to 100,n=12).Blood and Longissimus thoracis muscle were sampled from dams(100 d of gestation),fetuses(100 d of gestation),and kids(90 d after birth)in each group.The data were analyzed using the linear MIXED model,with the multiple comparison method of SIDAK applied.Intake restriction reduced(P<0.05)the total blood protein of dams and fetuses.Maternal restriction decreased(P<0.05)the cAMP-responsive element-binding protein 1(CREB1),CREB-binding protein(CREBBP),protein kinase A(PKA),aryl hydrocarbon receptor nuclear translocator-like protein 1(BMAL1),protein kinase B(AKT1),mammalian target of rapamycin(mTOR),and regulatory-associated protein of mTOR(RPTOR)mRNA expression in the fetuses,and reduced(P<0.05)the CREBBP,nuclear receptor subfamily 1 group H member 3(NR1 H3),D-box binding PAR bZIP transcription factor(DBP)and PKA mRNA levels in the kids,but increased(P<0.05)the peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1 A)and tuberous sclerosis 2(TSC2)mRNA levels in the fetuses.The mRNA expression of clock circadian regulator(CLOCK)and TSC2 genes was increased(P<0.05)in the restricted kids.The protein expression of total PKA and phosphorylated PKA in the restricted fetuses and kids were downregulated(P<0.05),and the protein expression of total mTOR and phosphorylated mTOR were reduced(P<0.05)in the restricted fetuses and kids.Maternal intake restriction regulated fat oxidation,protein synthesis,and circadian clock expression in the muscles of the offspring probably via the glucagon-mediated PKA-CREB pathway,which reveals a noteworthy molecular pathway that maternal undernutrition leads to metabolic adaptation of skeletal muscle in offspring.
文摘BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in these patients.However,their actual prevalence and pathophysiology remain to be elucidated.AIM To determine the prevalence of SMAs and to assess the significance of circulating myokines as biomarkers in patients with MASLD.METHODS Skeletal muscle strength and muscle mass were measured in a cross-sectional study in a cohort of 62 patients fulfilling MASLD criteria,recruited from the outpatient clinics of a tertiary level hospital.The degree of fibrosis and liver steatosis was studied using abdominal ultrasound and transitional elastography.Anthropometric and metabolic characteristics as well as serum levels of different myokines were also determined in the MASLD cohort.Statistical analysis was performed comparing results according to liver fibrosis and steatosis.RESULTS No significant differences were found in both skeletal muscle strength and skeletal muscle mass in patients with MASLD between different stages of liver fibrosis.Interestingly,serum levels of fibroblast growth factor-21(FGF21)were significantly higher in patients with MASLD with advanced hepatic fibrosis(F3-F4)than in those with lower fibrosis stages(F0-F2)(197.49±198.27 pg/mL vs 95.62±83.67 pg/mL;P=0.049).In addition,patients with MASLD with severe hepatosteatosis(S3)exhibited significantly higher serum levels of irisin(1116.87±1161.86 pg/mL)than those with lower grades(S1-S2)(385.21±375.98 pg/mL;P=0.001).CONCLUSION SMAs were uncommon in the patients with MASLD studied.Higher serum levels of irisin and FGF21 were detected in patients with advanced liver steatosis and fibrosis,respectively,with potential implications as biomarkers.
基金supported by the German Research Council(Deutsche Forschungsgemeinschaft,HA3309/3-1/2,HA3309/6-1,HA3309/7-1)。
文摘Skeletal muscles are essential for locomotion,posture,and metabolic regulation.To understand physiological processes,exercise adaptation,and muscle-related disorders,it is critical to understand the molecular pathways that underlie skeletal muscle function.The process of muscle contra ction,orchestrated by a complex interplay of molecular events,is at the core of skeletal muscle function.Muscle contraction is initiated by an action potential and neuromuscular transmission requiring a neuromuscular junction.Within muscle fibers,calcium ions play a critical role in mediating the interaction between actin and myosin filaments that generate force.Regulation of calcium release from the sarcoplasmic reticulum plays a key role in excitation-contraction coupling.The development and growth of skeletal muscle are regulated by a network of molecular pathways collectively known as myogenesis.Myogenic regulators coordinate the diffe rentiation of myoblasts into mature muscle fibers.Signaling pathways regulate muscle protein synthesis and hypertrophy in response to mechanical stimuli and nutrient availability.Seve ral muscle-related diseases,including congenital myasthenic disorders,sarcopenia,muscular dystrophies,and metabolic myopathies,are underpinned by dys regulated molecular pathways in skeletal muscle.Therapeutic interventions aimed at preserving muscle mass and function,enhancing regeneration,and improving metabolic health hold promise by targeting specific molecular pathways.Other molecular signaling pathways in skeletal muscle include the canonical Wnt signaling pathway,a critical regulator of myogenesis,muscle regeneration,and metabolic function,and the Hippo signaling pathway.In recent years,more details have been uncovered about the role of these two pathways during myogenesis and in developing and adult skeletal muscle fibers,and at the neuromuscular junction.In fact,research in the last few years now suggests that these two signaling pathways are interconnected and that they jointly control physiological and pathophysiological processes in muscle fibers.In this review,we will summarize and discuss the data on these two pathways,focusing on their concerted action next to their contribution to skeletal muscle biology.However,an in-depth discussion of the noncanonical Wnt pathway,the fibro/a dipogenic precursors,or the mechanosensory aspects of these pathways is not the focus of this review.
基金supported by The National Natural Science Foundation of China(82405429)The Medical and Health Science and Technology Program of Hangzhou(ZD20250272)+1 种基金Key Discipline of Traditional Chinese Medicine in Zhejiang Province(2024-XK-57)The Construction Fund of Key Medical Discipline of Hangzhou(2025HZZD16).
文摘Sarcopenia,a progressive and systemic skeletal muscle disorder marked by the accelerated deterioration of both muscle function and mass,is highly prevalent among the elderly population,significantly contributing to an elevated risk of adverse outcomes,including falls,fractures,and muscle weakness.Clinical investigations have identified a strong correlation between sarcopenia and several prevalent degenerative skeletal muscle disorders.This correlation is attributed to imbalances in joint mechanics resulting from localized muscle atrophy and the influence of musculoskeletal secretory factors.In this review,we discuss the broader implications of sarcopenia and critically evaluate the currently established assessment methods.Furthermore,the clinical significance of prevalent musculoskeletal disorders(including osteoporosis,osteoarthritis,and spinal pathologies)in relation to sarcopenia,alongside the underlying mechanisms influencing this relationship,is summarized.Additionally,the effects of sarcopenia on the therapeutic efficacy of medications and surgical interventions for musculoskeletal conditions are reviewed.Sarcopenia is intricately linked to the onset,progression,and prognosis of musculoskeletal disorders.Future research should prioritize elucidating the potential mechanisms that connect muscle loss with skeletal muscle diseases,and investigating whether mitigating sarcopenia symptoms could decelerate the progression of these disorders,thereby paving new pathways for therapeutic interventions.
文摘Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.
基金supported by the grants from the National Natural Science Foundation of China(32372873,32441084 and 32172720)the Program for Science&Technology Innovation Talents in Universities of Henan Province,China(22HASTIT038)the Zhongyuan Youth Talent Support Program of China(ZYYCYU202012156).
文摘Skeletal muscle satellite cells are stem cells characterized by their multipotency and capacity for in vitro proliferation.However,primary skeletal muscle satellite cells demonstrate limited proliferative capacity in vitro,which impedes their investigation in poultry skeletal muscle research.Cell immortalization techniques have emerged as valuable tools to address this limitation and facilitate the study of skeletal muscle satellite cell functions.This study achieved the immortalization of chicken skeletal muscle satellite cells through the transduction of primary cells with TERT(telomerase reverse transcriptase)amplified from chicken(chTERT)using a lentiviral vector via telomerase activity reconstitution.While the cells successfully overcame replicative senescence,complete immortalization was not achieved.Initial functional characterization revealed that the proliferative properties and cell cycle characteristics of the immortalized chicken skeletal muscle satellite cell lines(ICMS)closely resembled those of chicken primary muscle satellite cells(CPMSCs).Serum dependency analysis and soft agar assays confirmed that ICMS did not undergo malignant transformation.Furthermore,induced differentiation experiments demonstrated preserved differentiation capacity in ICMS.The established cell lines provide a fundamental framework for developing immortalized poultry cell lines and offer a cellular model for investigating poultry skeletal muscle-related functional genes.
基金supported by the Swedish Research Council(201500165)a Wallenberg Scholars Award from the Knut and Alice Wallenberg Foundation(KAW 2023.0312)The Novo Nordisk Foundation Center for Basic Metabolic Research is an independent research center at the University of Copenhagen,partially funded by an unrestricted donation from the Novo Nordisk Foundation(NNF23SA0084103).
文摘1.Exercise enhances muscle function and insulin sensitivity Skeletal muscle plays a fundamental role in not only locomotion,but also systemic metabolism.In people with type 2 diabetes,skeletal muscle is a major site of insulin resistance,with impaired insulin signaling and reduced glucose transport activity contributing to metabolic dysfunction.
文摘Metabolic dysfunction-associated steatotic liver disease is increasingly understood to be closely linked with skeletal muscle alterations,such as sarcopenia,myoste-atosis,and metabolic dysregulation,which play a key role in its pathogenesis and progression.Recent literature,including an article by Isakov,highlights the bidirectional interactions between muscle and liver,underscoring shared mechanisms such as insulin resistance,inflammation,and myokine imbalance.This letter reflects on key findings from the review,noting strengths such as its integration of mechanistic insights,discussion of emerging biomarkers,and emphasis on lifestyle and pharmacological interventions.It also identifies areas for further development,including standardization of diagnostic criteria and more rigorous evaluation of translational data.As muscle health gains promi-nence in metabolic dysfunction-associated steatotic liver disease research,multidisciplinary strategies that target both hepatic and muscular systems may offer more effective avenues for prevention and treatment.
文摘BACKGROUND Metastasis of renal cell carcinoma(RCC)to the skeletal muscle and small bowel is an exceedingly rare occurrence.Both of these sites are unusual sites for RCC to metastasize to and to occur simultaneously is even less common.CASE SUMMARY A 58-year-old male with known history of RCC presented with a recurrence that was diagnosed through imaging and biopsies.Mucosa abnormalities of small bowel noted during endoscopy were biopsied as well as lesion in the psoas muscle that was noted.CONCLUSION This case report emphasizes that RCC can not only recur but can do so even decades later and present as metastatic foci at atypical sites.
基金Supported by The National Natural Science Foundation of China,No.82103356.
文摘BACKGROUND Improving our understanding of whether increased dietary intake ofω-3 polyunsaturated fatty acids(PUFAs)is beneficial for increasing skeletal muscle mass in patients with metabolic dysfunction-associated fatty liver disease(MAFLD)could provide an important clinical evidence base for the development of relevant nutritional guidelines.AIM To investigate the effect of total dietaryω-3 PUFAs and their subtypes on skeletal muscle mass in MAFLD.METHODS This cross-sectional study involved 2316 participants from four National Health and Nutrition Examination Survey cycles between 2011 and 2018.Dietary intake ofω-3 PUFAs was collected through 24-hour dietary recall interviews.Appendicular skeletal muscle mass index(ASMI)was calculated by dividing ASM in kilograms by height squared.RESULTS The multiple linear regression model showed significant relationships for dietary intake of totalω-3 PUFAs with higher ASMI(β:0.06,95%CI:0.01-0.11)in MAFLD patients.Dietary a-linolenic acid(ALA)(β:0.06,95%CI:0.01-0.12),docosapentaenoic acid(β:1.28,95%CI:0.01-2.54),and docosahexaenoic acid(DHA)(β:0.19,95%CI:0.01-0.37)were significantly associated with higher ASMI,while intake of stearidonic acid and eicosapentaenoic acid did not improve ASMI.In patients with high probability of liver fibrosis,dietary intake of ALA was associated with higher ASMI(β:0.11,95%CI:0.03-0.18).Stratified analysis found that DHA was associated with higher ASMI in patients with obesity and higher metabolic risk.CONCLUSION Increasing dietary intake ofω-3 PUFAs improved skeletal muscle health in patients with MAFLD.Patient with obesity and higher metabolic risk were more likely to benefit from intake of DHA.
