Skeletal Muscle as an Endocrine Organ: The Role of Myokines in Exercise Adaptations

Advancements in two-dimensional nanomaterials for regenerative medicine in skeletal muscle repair

Skeletal muscle, the largest organ in the human body, plays vital roles in movement, heat generation, and internal organ protection. While healthy muscle can regenerate effectively, its regenerative capacity declines in conditions like congenital muscular dystrophy, severe trauma, or aging. Two-dimensional (2D) nanomaterials, with unique physicochemical properties such as high surface area, excellent biocompatibility, and tunable mechanical and electrical properties, have shown great promise in different forms of muscle injury, particularly in volumetric muscle loss (VML). Recent studies highlight their diverse applications in muscle regeneration, acting as cell recruitment platforms, drug delivery carriers, structural scaffolds, and anti-inflammatory agents. Additionally, their biological effects and intelligent responsiveness are emerging as key features. Despite these advances, safety concerns regarding toxicity and biodegradability remain a challenge for clinical application. To unlock the full potential of 2D materials, further research is needed, especially through interdisciplinary collaboration to better understand their biological effects. By addressing safety issues and harnessing their multifunctional and intelligent characteristics, 2D nanomaterials can offer a more effective and sustainable approach to skeletal muscle repair, paving the way for next-generation therapies in regenerative medicine.

Luteolin alleviates estrogen deficiency-induced muscle atrophy via targeting SLC7A11-mediated ferroptosis

BACKGROUND

Skeletal muscle atrophy, which is a debilitating condition exacerbated by estrogen deficiency, lacks effective therapeutic interventions. Although ferroptosis (an iron-dependent form of cell death driven by lipid peroxidation) has emerged as a contributor to muscle degeneration, its regulatory mechanisms remain poorly defined. In this study, we identified luteolin, which is a natural flavonoid, as a potent inhibitor of ferroptosis that mitigates estrogen deficiency-induced muscle atrophy by targeting SLC7A11.

PURPOSE

The aim of this study was to investigate the role of ferroptosis in the anti-muscle atrophy effects of luteolin.

METHODS

Via database screening, luteolin was identified as a potential drug for improving muscle atrophy, and the promotion of C2C12 myogenic differentiation by luteolin was detected by using immunofluorescence (IF), quantitative reverse transcription PCR (RT-qPCR) and western blot (WB). The mechanism of luteolin-mediated ferroptosis in muscle atrophy was confirmed by RNA-seq, transmission electron microscopy (TEM), and GSH, MDA, SOD and Fe2+ assays. Molecular docking, molecular dynamics simulation, surface plasmon resonance (SPR), cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and siRNA-mediated gene knockout were applied to validate the notion that the mechanism of luteolin treatment of muscle atrophy involves target binding to SLC7A11. In addition, this study confirmed the role of luteolin in ameliorating muscle atrophy via the modulation of the SLC7A11-mediated ferroptosis pathway in vivo. Finally, the effect of luteolin on the myogenic differentiation of HsKMCs was investigated.

RESULTS

Luteolin promotes myogenic differentiation and significantly inhibits myotube atrophy, with the main mechanism of these effects involving the direct binding of luteolin to the SLC7A11 protein to inhibit the occurrence of ferroptosis. We confirmed that luteolin can inhibit ferroptosis in muscle tissue and improve the loss of muscle mass and strength due to muscle atrophy in vivo. In addition, luteolin significantly inhibited myotube atrophy in HsKMCs and promoted their myogenic differentiation by modulating the SLC7A11-mediated ferroptosis.

CONCLUSIONS

Our findings demonstrate that luteolin regulates myogenesis and prevents muscle atrophy ​​through binding to SLC7A11 and subsequently inhibiting ferroptosis. This study elucidates the critical role of the SLC7A11-ferroptosis axis in preserving muscle physiology during atrophy, while identifying luteolin as a therapeutic agent capable of targeting SLC7A11 to suppress ferroptosis and alleviate muscle atrophy.

Optimization of high-intensity resistance exercise protocols for improving bone mineral density in the elderly without chronic diseases: a systematic review and network meta-analysis

Objective

This study aims to explore the effects of high-intensity resistance exercise (HIRE) protocols on improving bone mineral density (BMD) in the elderly without chronic diseases by using a forest plot and network meta-analysis.

Methods

A systematic search was performed across seven databases including PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, Wan Fang and VIP, to investigate the effects of HIRE on BMD in the elderly by December 9, 2024. The search strategy incorporated Boolean operators (AND, OR, NOT) to refine the selection of relevant studies. The methodological quality was assessed by using Risk of Bias tool 2 and Tool for the Assessment of Study Quality and Reporting in Exercise, and data analysis was performed using Stata 17.

Results

A total of 13 RCTs involving 616 participants were included. Among the various HIRE protocols, two demonstrated positive effects on lumbar spine and whole-body BMD, while four were positive in improving femoral neck BMD compared to the control group. The network meta-analysis revealed that 3M(9-10) was more effective than 2M(6-8), 3M(6-8) and 1M(6-8) in enhancing lumbar spine BMD. However, no significant differences were observed among the HIRE protocols for femoral neck and whole body BMD. According to the SUCRA rankings, 3M(9-10) was the most effective protocol for improving lumbar spine (94.7%) and femoral neck BMD (82.3%), while 2M(9-10) ranked highest for whole body BMD improvement (61.6%).

Conclusion

HIRE protocol is critical to ensure BMD improvement for elderly without chronic diseases, and not all HIRE protocols yield positive effects on BMD. Compared to other sites, lumbar spine BMD appears to be more responsive to HIRE. A 2-3 times, multiple-set regimen may be more beneficial for improving lumbar spine, whole-body, and femoral neck BMD in the elderly, and performing 9-10 repetitions per set is particularly important for improving BMD in older adults.

Systematic review registration number

https://www.crd.york.ac.uk/PROSPERO/, identifier registration number. CRD42024543517.

Silencing FGL1 promotes prostate cancer cell apoptosis and inhibits EMT progression

Emerging evidence from recent studies demonstrates that the FGL1/LAG-3 interaction axis plays a crucial role in mediating tumor immune evasion mechanisms, particularly through the suppression of T lymphocyte effector functions. However, the role of FGL1 in prostate cancer (PCa) remains unclear. Data was downloaded from The Cancer Genome Atlas (TCGA) database, and subjected to differential expression analysis. Single gene differential analysis to determine the correlation between FGL1 and DNAJC12 expression levels in prostate cancer. The expression of FGL1 was silenced by siRNA in PC3 prostate cancer cells. Lentiviruses infected DU145 to overexpress FGL1. Cell proliferation, apoptosis and EMT-related markers were detected in vitro. Animal experiments further confirmed the effect of FGL1 on prostate cancer. Up-regulated gene FGL1 was identified as the selected gene in this study among 3011 Differentially expressed genes. FGL1 had the highest positive relation with DNAJC12. The OS of PCa patients with high expression of FGL1 was significantly shorter. After silencing FGL1, PC3 cell proliferation was inhibited by 0.58-fold, while apoptosis increased by 16%, and the expression of cleaved-caspase-3 increased, while the expression of DNAJC12 and BCL-2 decreased. After overexpression of FGL1, the number of DU145 cells increased by 2.05-fold, the expression of cleaved-caspase-3 was inhibited, E-cadherin expression decreased, while N-cadherin and Vimentin expression increased. Tumor growth was inhibited, and the expression of FN1, n-cadherin, Vimentin and β-catenin decreased, while the expression of E-cadherin increased after silencing FGL1. Silencing FGL1 promotes prostate cancer cell apoptosis and inhibits EMT progression. FGL1 may be an independent prognostic marker and therapeutic target in PCa.

Immunosenescence in skeletal muscle: The role-play in cancer cachexia chessboard

With the increase in life expectancy, age-related conditions and diseases have become a widespread and relevant social burden. Among these, immunosenescence and cancer cachexia play a significant often intertwined role. Immunosenescence is the progressive aging decline of both the innate and adaptive immune systems leading to increased infection susceptibility, poor vaccination efficacy, autoimmune disease, and malignancies. Cancer cachexia affects elderly patients with cancer causing severe weight loss, muscle wasting, inflammation, and reduced response to therapies. Whereas the connections between immunosenescence and cancer cachexia have been raising attention, the molecular mechanisms still need to be completely elucidated. This review aims at providing the current knowledge about the interplay between immunosenescence, skeletal muscle, and cancer cachexia, analyzing the molecular pathways known so far to be involved. Finally, we highlight potential therapeutic strategies suited for elderly population aimed to block immunosenescence and to preserve muscle mass in cachexia, also presenting the analysis of the current state-of-the-art of related clinical trials.

Association Between the Serum Creatinine to Cystatin C Ratio and Cardiovascular Disease in Middle-Aged and Older Adults in China: A Nationwide Cohort Study

BACKGROUND

The relationship between the serum creatinine to cystatin C ratio (sarcopenia index [SI]) and the risk of incident cardiovascular disease (CVD) remains unclear. Therefore, this study aims to explore the association between SI and the risk of incident CVD in middle-aged and older Chinese adults using nationally representative data.

METHODS AND RESULTS

We analyzed data from participants in CHARLS (China Health and Retirement Longitudinal Study) conducted in 2015 and 2018. The exposure variable was SI, calculated as the ratio of serum creatinine to cystatin C, multiplied by 100. The outcome variable was self-reported CVD (heart disease or stroke). A cross-sectional analysis was first performed using 2015 CHARLS data, which included 11 115 eligible participants (46.1% men; mean±SD age, 60.28±9.60 years). Logistic regression was used to estimate the association between SI and CVD. Longitudinal analysis was then conducted using the 2018 follow-up data, which included 8589 participants (46.4% men; mean±SD age, 59.57±9.42 years), with a median follow-up period of 3.0 years. Cox proportional hazard models were used to assess the relationship between SI and the risk of incident CVD, and a multivariate-adjusted restricted cubic spline model was used to explore the dose-response relationship. In the cross-sectional analysis, multivariate logistic regression revealed a significant negative association between SI and CVD. The longitudinal analysis identified 854 (9.94%) new CVD cases. Cox models showed that lower SI was significantly associated with an increased risk of incipient CVD. The multivariable adjusted hazard ratios for participants in the quartile 2 to quartile4 groups compared with those in the quartile 1 group were 0.94 (95% CI, 0.79-1.12), 0.63 (95% CI, 0.51-0.78), and 0.60 (95% CI, 0.47-0.75), respectively. Restricted cubic spline curves demonstrated a significant linear relationship between SI and CVD incidence (all P-nonlinear>0.05).

CONCLUSIONS

A lower SI was significantly associated with an increased risk of new-onset CVD in middle-aged and older Chinese adults. This suggests that SI has an important potential application as a serum marker of sarcopenia in predicting CVD.

The Influence of an Acute Endurance Intervention on Breast Cancer Cell Growth-A Pilot Study

Exercise potentially inhibits tumor growth. It remains unclear which processes mediate these effects. Alterations of cytokine concentration in serum can influence cancer cell growth and may cause cell growth inhibition. This pilot study examines whether exercise-induced conditioning in serum can directly affect tumor cells. It focuses on serum collected before and after acute endurance exercise and its impact in vitro. Participants underwent a 1 h endurance training on a cycle ergometer. Samples were collected before, after, and two hours post-exercise. MDA-MB-231 cells were incubated with serum, and cell vitality and proliferation were assessed. Cytokine arrays identified relevant cytokine concentration changes. After identifying CXCL9 as a possible contributor to inhibitory effects, we inhibited the CXCR3 pathway and reassessed vitality. Exercise-conditioned serum significantly reduced cell vitality and proliferation post-intervention and after resting. Cytokine arrays revealed changes in multiple concentrations, and the inhibition of CXCL9 resulted in growth inhibitory effects. Our findings suggest that serum conditioned by an endurance intervention causes changes in cancer cell growth. Based on our observations, the alterations in serum cause growth-inhibitory effects, possibly mediated through the CXCR3 axis. This study provides preliminary evidence supporting the role of exercise in modulating the cancer cell growth directly by changes in serum.

A Single Intraperitoneal Secreted Protein Acidic and Rich in Cysteine Injection in Mice Is Towards an Exercise-like Phenotype

Secreted protein acidic and rich in cysteine (SPARC) is a protein widely expressed in various tissues. The metabolic and functional exploration of SPARC indicated it as a mediator of the exercise-induced effects. Furthermore, SPARC overexpression mimics exercise effects (including anti-aging phenotype), whereas its knockout both reduces the exercise-induced phenotype and increases aging. Each of these previous studies has been carried out for weeks and, therefore, indicates chronic effects of SPARC. To complete the puzzle, there is a need to explore the acute effects of SPARC. Thus, this study reports results of selected molecular and metabolic explorations of mice following a single injection of SPARC. Following both a validation of the Western blot as a detection method of SPARC in the serum and the optimization of the post-injection sacrifice time, mice (male and female) were injected with either SPARC or saline and sacrificed after 4 h. Body weight, selected tissues weights, and glycemia were measured. Muscle (tibialis anterior)-that was also harvested after the sacrifice and frozen-was used to measure the expression of selected proteins related to metabolism, protein hemostasis, and muscle development. Briefly, the results indicate a protein expression pattern towards improved glucose metabolism, oxidative phosphorylation, mitochondrial biogenesis, extracellular matrix remodeling, myogenesis, and protein synthesis. On the other hand, the expression of other proteins is towards decreased muscle protein degradation. There were no significant effects of SPARC injection on glycemia. These findings represent an important step towards developing a pharmacology based on injecting SPARC to achieve therapeutic effects that basically mimic exercise benefits, including anti-aging, metabolic enhancement, and muscle development. This is of particular importance for individuals who are unable to perform the required physical activity due to physical disabilities, aging, or hospitalization.

Soft Biological Actuators for Meter-Scale Homeostatic Biohybrid Robots

Skeletal muscle's elegant protein-based architecture powers motion throughout the animal kingdom, with its constituent actomyosin complexes driving intra- and extra-cellular motion. Classical motors and recently developed soft actuators cannot match the packing density and contractility of individual muscle fibers that scale to power the motion of ants and elephants alike. Accordingly, the interdisciplinary fields of robotics and tissue engineering have combined efforts to build living muscle actuators that can power a new class of robots to be more energy-efficient, dexterous, and safe than existing motor-powered and hydraulic paradigms. Doing so ethically and at scale─creating meter-scale tissue constructs from sustainable muscle progenitor cell lines─has inspired innovations in biomaterials and tissue culture methodology. We weave discussions of muscle cell biology, materials chemistry, tissue engineering, and biohybrid design to review the state of the art in soft actuator biofabrication. Looking forward, we outline a vision for meter-scale biohybrid robotic systems and tie discussions of recent progress to long-term research goals.

Optimizing electrical field stimulation parameters reveals the maximum contractile function of human skeletal muscle microtissues

Skeletal muscle microtissues are engineered to develop therapies for restoring muscle function in patients. However, optimal electrical field stimulation (EFS) parameters to evaluate the function of muscle microtissues remain unestablished. This study reports a protocol to optimize EFS parameters for eliciting contractile force of muscle microtissues cultured in micropost platforms. Muscle microtissues were produced across an opposing pair of microposts in polydimethylsiloxane and polymethyl methacrylate culture platforms using primary, immortalized, and induced pluripotent stem cell-derived myoblasts. In response to EFS between needle electrodes, contraction deflects microposts proportional to developed force. At 5 V, pulse durations used for native muscle (0.1-1 ms) failed to elicit contraction of microtissues; durations reported for engineered muscle (5-10 ms) failed to elicit peak force. Instead, pulse durations of 20-80 ms were required to elicit peak twitch force across microtissues derived from five myoblast lines. Similarly, although peak tetanic force occurs at 20-50 Hz for native human muscles, it varied across microtissues depending on the cell line type, ranging from 7 to 60 Hz. A new parameter, the dynamic oscillation of force, captured trends during rhythmic contractions, whereas quantifying the duration-at-peak force provides an extended kinetics parameter. Our findings indicate that muscle microtissues have cell line type-specific contractile properties, yet all contract and relax more slowly than native muscle, implicating underdeveloped excitation-contraction coupling. Failure to optimize EFS parameters can mask the functional potential of muscle microtissues by underestimating force production. Optimizing and reporting EFS parameters and metrics is necessary to leverage muscle microtissues for advancing skeletal muscle therapies.NEW & NOTEWORTHY Electrical field stimulation (EFS) parameters remain to be standardized for engineered skeletal muscle. Herein, we report a protocol for defining EFS parameters that elicit the maximal contractile force of muscle microtissues cultivated in micropost devices and highlight the value of developing appropriate metrics. The dynamic oscillation of force and duration-at-peak force are introduced as novel metrics of contraction kinetics.

The role of irisin in exercise-induced muscle and metabolic health: a narrative review

Irisin, a myokine released during physical exercise, has emerged as a key mediator of muscle health and metabolic regulation. This review synthesizes current evidence on how aerobic exercise stimulates irisin release and its subsequent effects, including enhanced muscle mass, strength, and recovery. Additionally, irisin promotes the browning of white adipose tissue, improving fat metabolism and glucose regulation. These adaptations position irisin as a promising therapeutic target for preventing metabolic disorders and optimizing exercise protocols. By exploring human studies and mechanistic insights, this review underscores irisin's potential to address global health challenges, such as obesity and type 2 diabetes, while advancing strategies for personalized exercise interventions.

Chronic musculoskeletal pain and its association with cognitive function and sarcopenia in older adults: Characterization and change over three months

Pain, cognitive impairment, and sarcopenia share common risk factors and neurophysiological processes, but studies investigating cognition and sarcopenia in older adults with pain are scarce. This study's main aim was to compare cognition and sarcopenia between older adults with and without chronic pain. A secondary aim was to investigate predictors of cognition and sarcopenia at baseline and 3 months while adjusting for confounders. Participants (67 older adults with pain and 67 asymptomatic older adults) were assessed for sociodemographic and clinical information, pain (number of painful body sites - body chart, pain phenotype - PainDETECT, severity and disability - BPI, pain catastrophizing - PCS, and kinesiophobia - Tampa Scale), cognition (MoCA), sarcopenia (risk of sarcopenia - SARC-F, hand grip strength, and calf circumference) and physical activity (RAPA) at baseline and 3 months after. Older adults with and without pain did not differ in cognition (Mean (95% CI): Pain = 21.47 (20.60; 22.34); Asymptomatic = 21.75 (20.89; 22.61)), but older adults with pain had greater signs of sarcopenia than asymptomatic older adults, including higher risk of sarcopenia (Mean (95%CI): Pain=2.89 (2.41; 3.37); Asymptomatic=0.50 (0.32; 0.68)) and lower hand grip strength (Pain=24.01 (21.74; 26.29); Asymptomatic=27.98 (25.80; 30.16)). No between-group differences were found for calf circumference (Pain=35.03 (34.26; 35.79); Asymptomatic=34.55 (33.86; 35.24)). Pain phenotype (baseline) and kinesiophobia (3 months) contributed to poorer cognition. Kinesiophobia and catastrophizing (baseline), and pain severity (3 months) contributed to sarcopenia. Despite no differences in cognition between older adults with and without pain, pain-related variables contributed to explaining sarcopenia and cognition. PERSPECTIVE: This study compared cognition and sarcopenia between older adults with and without pain and explored the association between pain, cognition, and sarcopenia. Groups were similar for cognition, but older adults with pain showed higher signs of sarcopenia. Kinesiophobia and pain severity partially explained cognition and sarcopenia among those with pain.

Relationship between different physical activity parameters and cognitive impairment in middle-aged and older adults: insights from a 4-year longitudinal study

BACKGROUND

Physical activity (PA) is crucial for the prevention and management of chronic diseases and may be associated with cognitive impairment. This study investigated the longitudinal relationship between PA from different parameters (e.g., frequency, duration, intensity, and volume) and the incidence of cognitive impairment in middle-aged and older adults.

METHODS

Data were derived from the China Health and Retirement Longitudinal Study (2011-2015). A total of 891 adults aged 45 and older were included in this study. Cognitive function was assessed using the Telephone Interview for Cognitive Status criteria, focused on episodic memory and executive function. We categorized participants into normal cognition and cognitive impairment groups. Self-reported PA information including frequency, duration, intensity, and volume was collected through a representative survey. Poisson regression analysis was employed to explore the relationship between PA parameters and the incidence of cognitive impairment over four years.

RESULTS

Engaging in moderate or light PA (MPA or LPA) at least three days per week, and vigorous PA (VPA) one to two days per week, was associated with a reduced incidence of cognitive impairment. Additionally, spending 30-119 min per day or 150 min per week or more on any PA intensity was linked to lower cognitive impairment prevalence. Sensitivity analysis, excluding individuals with neurological, mental, or memory impairments, confirmed these findings.

CONCLUSIONS

The findings highlight that the frequency, duration, and volume of VPA, MPA, or LPA are linked to the incidence of cognitive impairment. Regular PA may reduce the risk of cognitive impairment in middle-aged and older adults.

Body Composition and Its Outcomes and Management in Multiple Sclerosis: Narrative Review

Background: There is emerging interest in obesity and its prevalence, outcomes, and management in people with multiple sclerosis (MS). Body mass index (BMI) is the traditional marker of obesity in MS, whereas body composition, inclusive of specific body tissue compartments (e.g., fat, bone, and muscle), is often overlooked despite its relevance. Objective: This narrative review (a) underscored the use and utility of dual-energy X-ray absorptiometry (DEXA) as an accurate and reliable measure of body composition; (b) thematically analyzed and synthesized the current evidence regarding body composition (using DEXA); and (c) determined gaps to be addressed in future research. Methods: The structure and reporting of this narrative review followed the guiding criteria outlined in the Scale for the Assessment of Narrative Review Articles (SANRA). The relevant literature for this narrative review was identified via a PubMed search utilizing combined search terms such as 'body composition' and 'multiple sclerosis'. The identified research was then organized by the authors into major themes and sub-themes. The articles described within the narrative review were based on saturation of the identified themes and sub-themes. Results: Three major themes were identified, namely (1) comparison of body composition between people with MS and non-MS controls (2 meta-analyses); (2) examination of the relationships between body composition and a range of outcomes (14 cross-sectional studies); and (3) interventions that report and/or target body composition in MS (11 clinical trials). Conclusions: This narrative review mapped the existing evidence regarding body composition in MS, and posits body composition as a novel, informative, and targeted concept for this population. The narrative review underscores the importance of randomized controlled trials that focus on body composition as a significant and modifiable outcome. Such research could improve the understanding of obesity and poor body composition in MS and identify useful clinical recommendations for diagnosis and management.

The Power of Exercise: Unlocking the Biological Mysteries of Peripheral-Central Crosstalk in Parkinson's Disease

BACKGROUND

Exercise is a widely recognized non-pharmacological treatment for Parkinson's Disease (PD). The bidirectional regulation between the brain and peripheral organs has emerged as a promising area of research, with the mechanisms by which exercise impacts PD closely linked to the interplay between peripheral signals and the central nervous system.

AIM OF REVIEW

This review aims to summarize the mechanisms by which exercise influences peripheral-central crosstalk to improve PD, discuss the molecular processes mediating these interactions, elucidate the pathways through which exercise may modulate PD pathophysiology, and identify directions for future research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review examines how exercise-induced cytokine release promotes neuroprotection in PD. It discusses how exercise can stimulate cytokine secretion through various pathways, including the gut-brain, muscle-brain, liver-brain, adipose-brain, and bone-brain axes, thereby alleviating PD symptoms. Additionally, the potential contributions of the heart-brain, lung-brain, and spleen-brain axes, as well as multi-axis crosstalk-such as the brain-gut-muscle and brain-gut-bone axes-are explored in the context of exercise therapy. The study highlights the need for further research into peripheral-central crosstalk and outlines future directions to address challenges in clinical PD therapy.

Insulin Sensitivity and Muscle Loss in the Absence of Diabetes Mellitus: Findings from a Longitudinal Community-Based Cohort Study

Background/Objectives: Muscle loss is a serious complication in chronic disease patients, yet studies on long-term changes in muscle mass based on insulin sensitivity in the absence of diabetes mellitus are scarce. This community-based cohort study analyzed the longitudinal association between insulin sensitivity and muscle loss in middle-aged South Korean adults. Methods: This study included 6016 subjects (aged 40-65 years) from the Korean Genome and Epidemiology Study, conducted between 2001 and 2016. Fat-free mass, fat mass, body weight, and kidney function were assessed biennially. Subjects were categorized into four groups based on the composite (Matsuda) insulin sensitivity index (ISI) quartiles. The primary outcome was muscle loss, defined as a decline in fat-free mass of 10% or more from baseline. The secondary outcome was the occurrence of all-cause mortality. Results: During 69,480 person-years of follow-up, muscle loss occurred in 311 (5.2%) subjects. Multivariable Cox regression revealed a reverse-graded association between insulin sensitivity and muscle loss risk. Hazard ratios (95% confidence intervals) for the second, third, and highest ISI quartiles were 0.70 (0.51-0.94), 0.69 (0.50-0.95), and 0.65 (0.46-0.92), respectively, compared with the lowest quartile. Insulin sensitivity, however, was not significantly associated with all-cause mortality, though the mortality risk was higher in individuals with muscle loss. Conclusions: A reverse-graded relationship between insulin sensitivity and muscle loss risk was identified in middle-aged South Korean adults, with the lowest risk in the highest ISI quartile. These findings suggest that higher insulin sensitivity may reduce the risk of muscle loss.

Association of sarcopenia with regional brain atrophy and white matter lesions in a general older population: the Hisayama Study

Sarcopenia has been reported to be associated with cognitive decline and the risk of dementia. However, few studies have addressed the association between sarcopenia and brain morphological changes in the general population. A total of 1373 community-dwelling participants aged ≥ 65 years underwent brain MRI. Sarcopenia was defined based on the Asian Working Group for Sarcopenia's criteria. The pattern of regional gray matter volume loss associated with sarcopenia were assessed using a voxel-based morphometry (VBM) analysis. Regional brain volumes, intracranial volumes (ICV), and white matter lesions volumes (WMLV) were also measured using FreeSurfer. An analysis of covariance was used to examine the associations of sarcopenia with regional brain volumes in proportion to ICV. Of the participants, 112 had sarcopenia. The participants with sarcopenia had significantly lower total brain volume/ICV and total gray matter volume/ICV and higher WMLV/ICV than those without sarcopenia after adjusting for confounders. In VBM, sarcopenia was associated with lower gray matter volume in the frontal lobe, insula, cingulate gyrus, hippocampus, amygdala, and basal ganglia. Using FreeSurfer, we confirmed that the participants with sarcopenia had significantly lower frontal, insular, cingulate, and hippocampal volumes than those without sarcopenia. The current study showed that participants with sarcopenia had significantly lower volume in the frontal lobe, insula, cingulate, and hippocampus and higher WMLV than participants without sarcopenia. As these brain regions are likely to play an important role in cognitive function, these changes may suggest a shared underlying mechanism for the progression of sarcopenia and cognitive decline.

Separate and Combined Effects of Moderate-Intensity Exercise Training and Detraining with Protocatechuic Acid (PCA) on Myokines and Insulin-Signaling Pathways in Male Wistar Rats: A Preclinical Randomized Study

Background: Exercise training positively modulates myokine secretion and improves glucose metabolism. Herein, we analyzed the effect of moderate-intensity training, detraining, and Protocatechuic Acid (PCA) supplementation on myokine secretions and regulation of insulin-signaling pathways. Methods: A five-arm study was conducted on 47 healthy male Wistar rats, trained at a moderate intensity level for four weeks (T0-T4). Animals were randomly classified into groups according to PCA supplementation and exercise durations: four weeks of Aerobic Training with or without PCA (AT4, AT4-PCA), eight weeks of Aerobic Training with or without PCA (AT8, AT8-PCA), and PCA Vehicle Control (VC). The animals were followed up until week 12 (T12). We decapitated six rats at T0 and T4, four rats per group at T8, and three rats per group at T12. Myokines (IGF-1, IL-6, FGF-21, myostatin, and irisin) were analyzed with ELISA. Western blot analysis measured protein expression of insulin-signaling pathways and GLUT-4 in the gastrocnemius muscle. Results: The IL-6 levels increased significantly (p < 0.01) with 8-week training in AT8 by 34% and AT8-PCA by 32%, compared to groups trained for only 4 weeks (AT4 and AT4-PCA). Similarly, the PI3K, and GLUT-4 expression improved in AT8 and AT8-PCA at T8. Training for 4 weeks improved IGF-1 levels, but a further 14% improvement was observed with 8-week training in AT8 at T8. Myostatin level significantly dropped by 27% even with 4-week training (p < 0.001). However, detraining increased the myostatin levels in all groups, but in AT8-PCA with PCA dose, myostatin reduced by 11% compared to AT8 at T12. PCA supplementation reduced the FGF-21 levels by 54% during detraining at T12 in AT8-PCA compared to AT8. However, the irisin level did not change markedly in any group. Conclusions: Physical training (with and without PCA) modulates myokine production and improves glucose metabolism, but the benefits are lost after detraining.

Muscle Strength and Cardiovascular Health in MASLD: A Prospective Study

Background and Objectives: The pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) remains incompletely understood. However, recent studies highlight the interactions between muscle, liver, and adipose tissue. This study aimed to explore the relationships between clinical indicators of MASLD and sarcopenia, cardiorespiratory fitness, fatigue, and mood. Materials and Methods: The study involved 60 participants, including 28 healthy controls and 32 with MASLD, categorized into two disease subgroups: 15 with MASL and 17 with metabolic dysfunction-associated steatohepatitis (MASH). Participants completed an incremental speed shuttle walk test to evaluate cardiorespiratory fitness, a hand-held dynamometer assessment for appendicular muscle strength, and the timed up and go test for physical performance. Physical activity level, fatigue, quality of life, and emotional state were assessed using questionnaires. The test results were compared between groups and with disease characteristics. Results: MASL and MASH groups showed reduced cardiorespiratory fitness (p < 0.001). The knee extensors were significantly weaker in both MASL and MASH groups (p < 0.001 and p = 0.001, respectively). The MASH group reported higher levels of depression and negative health perception (p = 0.006 and p = 0.03, respectively). Muscle strength in patients with MASLD showed a significant negative association with depression (OR = -0.384, 95% CI: -3.10 to -0.74, p = 0.003), intrahepatic triglyceride content (OR = -0.287, 95% CI: -1.31 to -0.11, p = 0.023), and LDL (OR = -0.286, 95% CI: -0.02 to -0.33, p = 0.03). In contrast, a positive association was observed between VO2 and muscle strength (OR = 0.531, 95% CI 1.27 to 3.47, p < 0.001). Conclusions: This study suggests that muscle strength is linked to key metabolic parameters, such as hepatic fat, LDL levels, and aerobic capacity, that may contribute to the development and progression of MASLD. Interventions aimed at preserving or enhancing muscle strength in MASLD patients may be essential for preventing liver damage and improving metabolic health.

Relationship of irisin and apelin levels with sarcopenia and body composition in community-dwelling older adults: a paired case-control study

Irisin and apelin levels continue to decrease with age, and although many previous studies have explored their association with sarcopenia and body composition, there is still a paucity of evidence relating to them in community-dwelling elderly populations. The aim of this study was to provide new evidence for the association of irisin and apelin with sarcopenia in older adults. This case-control study included 80 individuals with sarcopenia and 80 individuals without sarcopenia. The definition of sarcopenia was based on the Asian Working Group for Sarcopenia 2019 criteria. Plasma levels of irisin and apelin were measured using an enzyme-linked immunosorbent assay. Conditional logistic regression analysis was performed to estimate odds ratios (ORs) and 95% CIs. The sarcopenia group exhibited significantly lower levels of irisin (73.75 ± 30.97 ng/mL vs. 131.15 ± 88.38 ng/mL, p < 0.001) and apelin (21.51 ± 14.89 ng/mL vs. 27.87 ± 14.41 ng/mL, p = 0.007) compared to the control group. Increased levels of irisin (OR, 0.98, 95% CI, 0.97-0.99) and apelin (OR, 0.97, 95% CI, 0.95-0.99) were associated with a decreased risk of sarcopenia. In women, irisin was positively associated with body mass index, intracellular water (ICW), extracellular water (ECW), total water (TW), protein, mineral, fat, fat-free mass, skeletal muscle mass (SMM), percentage body fat, waist circumference, visceral fat area, and basal metabolic rate. Apelin was positively associated with ICW, ECW, TW, protein, and SMM (all p < 0.05). In men, positive correlations were found between irisin, apelin, and handgrip strength (all p < 0.05). Receiver operating characteristic analysis showed that irisin and apelin had moderate predictive power in identifying sarcopenia. Plasma irisin and apelin were lower than in controls in elderly patients with sarcopenia, and elevated levels of irisin and apelin were associated with a reduced risk of sarcopenia. In addition, irisin and apelin levels are associated with body composition and irisin showed a stronger ability to predict sarcopenia in women.

A feeding-induced myokine modulates glucose homeostasis

Maintaining blood glucose homeostasis during fasting and feeding is crucial for the prevention of dysregulation that can lead to either hypo- or hyperglycaemia. Here we identified feimin, encoded by a gene with a previously unknown function (B230219D22Rik in mice, C5orf24 in humans), as a key modulator of glucose homeostasis. Feimin is secreted from skeletal muscle during feeding and binds to its receptor, receptor protein tyrosine kinase Mer (MERTK), promoting glucose uptake and inhibiting glucose production by activation of AKT. Administration of feimin and insulin synergistically improves blood glucose homeostasis in both normal and diabetic mice. Notably, a specific single nucleotide polymorphism (rs7604639, G>A) within the MERTK gene, causing an amino acid substitution (R466K) within the feimin-MERTK binding region, leads to reduced association with feimin and elevated postprandial blood glucose and insulin levels in humans. Our findings underscore a role of the feimin-MERTK signalling axis in glucose homeostasis, providing valuable insights into potential therapeutic avenues for diabetes.

Long-Term Aerobic Exercise Enhances Hepatoprotection in MAFLD by Modulating Exosomal miR-324 via ROCK1

BACKGROUND

Insulin resistance (IR) is central to the progression of non-alcoholic fatty liver disease (MAFLD). While aerobic exercise reduces hepatic fat and enhances insulin sensitivity, the specific mechanisms-particularly those involving exosomal pathways-are not fully elucidated.

METHOD

Exosomes were isolated from 15 MAFLD patients' plasma following the final session of a 12-week aerobic exercise intervention. Liver fat content was measured using MRI-PDFF, and metabolic parameters were assessed via OGTT, HOMA-IR, QUICKI, and VO2 max. Co-culture experiments evaluated the effects of exercise-derived exosomes on IR signaling pathways. miRNA microarray analysis identified miR-324, which was quantified in high-fat diet (HFD) mice with and without exercise and compared between athletes and sedentary controls. Functional assays assessed miR-324's role in glucose and lipid metabolism, while luciferase reporter and Western blot assays confirmed ROCK1 as its direct target.

RESULT

Aerobic exercise significantly reduced liver fat and improved insulin sensitivity in both MAFLD patients and HFD mice. Notably, exosomal miR-324 levels were lower in athletes than sedentary controls, indicating an inverse association with insulin sensitivity. Post-exercise, precursor and mature miR-324 increased in adipose tissue and decreased in muscle, suggesting its adipose origin and inverse regulation. Functional assays demonstrated that miR-324 modulates insulin resistance by targeting ROCK1.

CONCLUSION

Exercise-induced exosomal miR-324 from adipose tissue targets ROCK1, revealing a novel mechanism by which aerobic exercise confers hepatoprotection against insulin resistance in MAFLD. These findings enhance our understanding of how exercise influences metabolic health and may inform future therapeutic strategies for managing MAFLD and related conditions.

Handgrip strength, cardiometabolic risk and body composition in youth with type 1 diabetes: the Diactive-1 Cohort Study

Objective

This study aimed to explore the association between handgrip strength, cardiometabolic risk (CMR) and body composition in youth with type 1 diabetes.

Methods

For this prospective cohort study, muscular fitness was assessed via handgrip test and relativised by weight, and body composition, evaluated through dual-energy X-ray absorptiometry in type 1 diabetes patients aged 6-18 years. CMR score included z-scores for total body fat, blood pressure, glycated haemoglobin (HbA1c), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride-glucose index.

Results

Eighty-three patients were analysed at baseline and 1-year follow-up (44.6% females, mean age 12.77 years). Individuals with high handgrip strength tended to have lower CMR and body fat compared with those with low handgrip strength. Over a year, individuals with high handgrip strength showed reduced HbA1c, CMR and subcutaneous fat. Consistently meeting high handgrip strength criteria resulted in reductions in HbA1c levels, CMR score and subcutaneous adipose tissue compared with those who never complied or lost compliance during follow-up. Additionally, subjects classified with high handgrip strength both at baseline and follow-up had a lower likelihood of being classified with high CMR (OR=0.241, 95% CI 0.121 to 0.947, p=0.044).

Conclusions

High handgrip strength was associated with significant cardiometabolic and body composition benefits in youth with type 1 diabetes. This tool could be considered of potential clinical value for incorporating assessments like handgrip tests to monitor and address cardiometabolic health.

Association of Muscle Strength With All-Cause Mortality in the Oldest Old: Prospective Cohort Study From 28 Countries

BACKGROUND

Ageing is associated with a gradual loss of muscle strength, which in the end may have consequences for survival. Whether muscle strength and mortality risk associate in a gradual or threshold-specific manner remains unclear. This study investigates the prospective association of muscle strength with all-cause mortality in the oldest old.

METHODS

We included 1890 adults aged ≥ 90 years (61.6% women, mean age 91.0 ± 1.5 years) from 27 European countries and Israel participating in the Survey of Health, Ageing and Retirement in Europe (SHARE) study. Muscle strength was assessed using handgrip dynamometry (unit: kilogram). Using time-varying Cox regression with restricted cubic splines, we determined the prospective association of muscle strength with mortality, controlling for age, sex, smoking, BMI, marital status, education, geographical region and self-perceived health.

RESULTS

Over a mean follow-up of 4.2 ± 2.4 years, more than half of the participants died (n = 971, 51.4%). The mean handgrip strength was 20.4 ± 8.0 kg for all participants, with men (26.7 ± 7.5 kg) showing significantly higher strength than women (16.4 ± 5.4 kg) (p < 0.001). Using the median level of muscle strength as reference (18 kg), lower and higher levels were associated in a gradual and curvilinear fashion with higher and lower mortality risk, respectively. The 10th percentile of muscle strength (10 kg) showed a hazard ratio (HR) of 1.27 (95% CI 1.13-1.43, p < 0.001). The 90th percentile (31 kg) showed an HR of 0.69 (95% CI 0.58-0.82, p < 0.001). Stratified for sex, the median levels of muscle strength were 26 kg for men and 16 kg for women. The 10th percentile of muscle strength showed HRs of 1.33 (95% CI 1.10-1.61, p < 0.001) at 15 kg for men and 1.19 (95% CI 1.05-1.35, p < 0.01) at 10 kg for women. The 90th percentile of muscle strength showed HRs of 0.75 (95% CI 0.59-0.95, p < 0.01) at 35 kg for men and 0.75 (95% CI 0.62-0.90, p < 0.001) at 23 kg for women. Sensitivity analyses, which excluded individuals who died within the first 2 years of follow-up, confirmed the main findings.

CONCLUSION

Rather than a specific threshold, muscle strength is gradually and inversely associated with mortality risk in the oldest old. As muscle strength at all ages is highly adaptive to resistance training, these findings highlight the importance of improving muscle strength in both men and women among the oldest old.

Effects of multidisciplinary therapy on energy balance, inflammation, and metabolic diseases in adolescents with obesity: A narrative review

Obesity is a consequence of multiple factors, including genetics, lifestyle and nutritional choices, physical activity, sleep duration, screen time, and mood disorders. These behavioral elements can impair the regulation of energy balance and obesity management that link obesity to a constellation of chronic conditions that lead to a high prevalence of cardiometabolic risk factors, metabolic syndrome, and nonalcoholic fatty liver disease. Multidisciplinary therapy is defined as an approach delivered by a multidisciplinary-trained health team covering at least two components of behavior, physical activity/exercise, dietary habits, and/or psychological counseling associated with clinical interventions. This narrative review summarizes the effects of multidisciplinary therapy on neuroendocrine regulation of energy balance, inflammatory biomarkers, cardiometabolic risk factors, metabolic syndrome, nonalcoholic fatty liver diseases, behavior, and quality of life. We found that multidisciplinary therapy, including medical, nutritional, exercise, and behavioral counseling, and/or education, was useful for addressing outcomes such as visceral adiposity, neuroendocrine regulation of energy balance, inflammatory biomarkers, cardiometabolic risk factors, nonalcoholic fatty liver disease, and metabolic syndrome. The effects were mediated by improvements in neuroendocrine regulation of energy balance, downregulation of the pro-inflammatory states, and a reduction in comorbidities. Multidisciplinary therapy also improved mood disorders and quality of life.

Advances in body composition and gender differences in susceptibility to frailty syndrome: Role of osteosarcopenic obesity

There is general consensus that an improper diet negatively impacts health and that nutrition is a primary tool for the prevention of non-communicable diseases. Unfortunately, the importance of studying body composition, which can reveal early predictors of gender-related diseases, is still not well understood in this context. Currently, individuals are still classified as obese based solely on their body mass index, without considering the amount of fat, its distribution, and the quantity of muscle and bone mass. In this regard, the body composition phenotype defined as "osteosarcopenic obesity" affects approximately 6-41 % of postmenopausal women, with prevalence increasing with age due to the hormonal and metabolic changes that occur during this period. This particular phenotype arises from the strong relationship between visceral fat, muscle, bone, and gut microbiota and predispose postmenopausal women to frailty. Frailty is a complex clinical phenomenon with significant care and economic implications for our society. Recent studies suggest that women have a higher prevalence of frailty syndrome and its individual components, such as osteoporosis, fractures and sarcopenia, compared to men. Here, we provide a comprehensive overview of recent advances regarding the impact of gender on body composition and frailty. Furthermore, we reflect on the crucial importance of personalized nutritional interventions, with a focus on reducing visceral fat, increasing protein intake and optimizing vitamin D levels. A review of the scientific literature on this topic highlights the importance of studying body composition for a personalized and gender-specific approach to nutrition and dietetics, in order to identify frailty syndrome early and establish personalized treatments. This new method of researching disease predictors could likely help clarify the controversial results of studies on vitamin D, calcium and proteins, translate into practical wellness promotion across diverse elderly populations.

Skeletal muscle as a pro- and anti-inflammatory tissue: insights from children to adults and ultrasound findings

Previously regarded as a movement and posture control agent, the skeletal muscle is now recognized as an endocrine organ that may affect systemic inflammation and metabolic health. The discovery of myokines such as IL-6, released from skeletal muscle in response to physical exercise, is now one of the most recent insights. Myokines are the mediators of the balance between the pro-inflammatory and anti-inflammatory responses. This underscores the muscle function as a determinant of good health and prevention of diseases. Advances in ultrasound technology improved evaluation of muscle thickness, composition, and determining fat distribution. Combining imaging with molecular biology, researchers discovered the complicated interplay between muscle function, cytokine production and general health effects.The production of myokines with exercise showcasing the adaptability of muscles to high-stress conditions and contributing to metabolism and inflammation regulation. These findings have significant implications in order to provide improvement in metabolic and inflammatory diseases.

Relationship between skeletal muscle mass change and swallowing function improvement among stroke patients with dysphagia during rehabilitation

OBJECTIVES

The purpose of this study was to evaluate the relationship between changes in skeletal muscle mass and improvements in swallowing function in stroke patients with dysphagia during rehabilitation.

METHODS

The study included 145 patients with a stroke or dysphagia. The two groups were divided into two groups: those with improved skeletal muscle mass index (SMI) at discharge and those without. Clinical data, including SMI, and Mann Assessment of Swallowing Ability (MASA), were collected from the database.

RESULTS

The increase in MASA was significantly higher in the group with increased SMI than in the group with no increase in SMI. In the multivariate analysis, the duration of rehabilitation and the group with increased SMI were associated with increased MASA.

CONCLUSION

SMI gain and the duration of rehabilitation per day were associated with improved swallowing function in patients with stroke.

Resistance Exercise Improves Glycolipid Metabolism and Mitochondrial Biogenesis in Skeletal Muscle of T2DM Mice via miR-30d-5p/SIRT1/PGC-1α Axis

Exercise is a recognized non-pharmacological treatment for improving glucose homeostasis in type 2 diabetes (T2DM), with resistance exercise (RE) showing promising results. However, the mechanism of RE improving T2DM has not been clarified. This study aims to investigate the effects of RE on glucose and lipid metabolism, insulin signaling, and mitochondrial function in T2DM mice, with a focus on the regulatory role of miR-30d-5p. Our results confirmed that RE significantly improved fasting blood glucose, IPGTT, and ITT in T2DM mice. Enhanced expression of IRS-1, p-PI3K, and p-Akt indicated improved insulin signaling. RE improved glycolipid metabolism, as well as mitochondrial biogenesis and dynamics in skeletal muscle of T2DM mice. We also found that miR-30d-5p was upregulated in T2DM, and was downregulated after RE. Additionally, in vitro, over-expression of miR-30d-5p significantly increased lipid deposition, and reduced glucose uptake and mitochondrial biogenesis. These observations were reversed after transfection with the miR-30d-5p inhibitor. Mechanistically, miR-30d-5p regulates glycolipid metabolism in skeletal muscle by directly targeting SIRT1, which affects the expression of PGC-1α, thereby influencing mitochondrial function and glycolipid metabolism. Taken together, RE effectively improves glucose and lipid metabolism and mitochondrial function in T2DM mice, partly through regulating the miR-30d-5p/SIRT1/PGC-1α axis. miR-30d-5p could serve as a potential therapeutic target for T2DM management.

Exercise training mode effects on myokine expression in healthy adults: A systematic review with meta-analysis

BACKGROUND

The benefits of exercise are well known; however, many of the underlying molecular mechanisms are not fully understood. Skeletal muscle secretes myokines, which mediate muscle-organ crosstalk. Myokines regulate satellite-cell proliferation and migration, inflammatory cascade, insulin secretion, angiogenesis, fatty oxidation, and cancer suppression. To date, the effects of different exercise modes (namely, aerobic and resistance exercise) on myokine response remain to be elucidated. This is crucial considering the clinical implementation of exercise to enhance general health and wellbeing and as a medical treatment.

METHODS

A systematic search was undertaken in PubMed, MEDLINE, CINAHL, Embase, SPORTDiscus, and Web of Science in April 2023. Eligible studies examining the effects of a single bout of exercise on interleukin15 (IL-15), irisin, secreted protein acidic and rich in cysteine (SPARC), oncostatin M (OSM), and decorin were included. A random-effects meta-analysis was also undertaken to quantify the magnitude of change.

RESULTS

Sixty-two studies were included (n = 1193). Overall, exercise appeared to induce small to large increases in myokine expression, with effects observed immediately after to 60 min post-exercise, although these were mostly not statistically significant. Both aerobic and resistance exercise resulted in changes in myokine levels, without any significant difference between training modes, and with the magnitude of change differing across myokines. Myokine levels returned to baseline levels within 180 min to 24 h post-exercise. However, owing to potential sources of heterogeneity, most changes were not statistically significant, indicating that precise conclusions cannot be drawn.

CONCLUSION

Knowledge is limited but expanding with respect to the impact of overall and specific effects of exercise on myokine expression at different time points in the systemic circulation. Further research is required to investigate the effects of different exercise modes at multiple time points on myokine response.

Neuromuscular mechanisms for the fast decline in rate of force development with muscle disuse - a narrative review

The removal of skeletal muscle tension (unloading or disuse) is followed by many changes in the neuromuscular system, including muscle atrophy and loss of isometric maximal strength (measured by maximal force, Fmax). Explosive strength, i.e. the ability to develop the highest force in the shortest possible time, to maximise rate of force development (RFD), is a fundamental neuromuscular capability, often more functionally relevant than maximal muscle strength. In the present review, we discuss data from studies that looked at the effect of muscle unloading on isometric maximal versus explosive strength. We present evidence that muscle unloading yields a greater decline in explosive relative to maximal strength. The longer the unloading duration, the smaller the difference between the decline in the two measures. Potential mechanisms that may explain the greater decline in measures of RFD relative to Fmax after unloading are higher recruitment thresholds and lower firing rates of motor units, slower twitch kinetics, impaired excitation-contraction coupling, and decreased tendon stiffness. Using a Hill-type force model, we showed that this ensemble of adaptations minimises the loss of force production at submaximal contraction intensities, at the expense of a disproportionately lower RFD. With regard to the high functional relevance of RFD on one hand, and the boosted detrimental effects of inactivity on RFD on the other hand, it seems crucial to implement specific exercises targeting explosive strength in populations that experience muscle disuse over a longer time.

Irisin expression and FNDC5 (rs3480) gene polymorphism in type 2 diabetic patients with and without CAD

BACKGROUND

Irisin was found to correlate with coronary artery disease (CAD) in diabetic patients. This study investigated the association of irisin and FNDC5 (SNP rs3480) with the presence and severity of CAD in T2DM.

METHODS

This cross-sectional study included 100 patients with T2DM divided into two groups, DM group (n = 50), including patients without CAD and CAD group (n = 50), including those confirmed to have CAD by coronary angiography. Irisin was measured. SNP rs3480 genotyping of FNDC5 was done.

RESULTS

Irisin levels were significantly lower in the CAD group (p < 0.001). The CAD group had significantly higher HbA1c and lower HDL (p < 0.001). Patients with controlled DM had significantly higher irisin levels (p < 0.001). single nucleotide polymorphism (SNP) rs3480 was not associated with irisin levels, and the FNDC5 rs3480 AA reference allele was significantly associated with significant CAD.

CONCLUSION

Irisin appears to be protective against developing CAD in diabetic patients. Irisin level was an independent predictor of significant CAD in diabetic patients combined with the FNDC5 rs3480 genotype.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04957823.

Research Progress on the Effects of Different Exercise Modes on the Secretion of Exerkines After Spinal Cord Injury

Exercise training is a conventional treatment strategy throughout the entire treatment process for patients with spinal cord injury (SCI). Currently, exercise modalities for SCI patients primarily include aerobic exercise, endurance training, strength training, high-intensity interval training, and mind-body exercises. These exercises play a positive role in enhancing skeletal muscle function, inducing neuroprotection and regeneration, thereby influencing neural plasticity, reducing limb spasticity, and improving motor function and daily living abilities in SCI patients. However, the mechanism by which exercise training promotes functional recovery after SCI is still unclear, and there is no consensus on a unified and standardized exercise treatment plan. Different exercise methods may bring different benefits. After SCI, patients' physical activity levels decrease significantly due to factors such as motor dysfunction, which may be a key factor affecting changes in exerkines. The changes in exerkines of SCI patients caused by exercise training are an important and highly relevant and visual evaluation index, which may provide a new research direction for revealing the intrinsic mechanism by which exercise promotes functional recovery after SCI. Therefore, this article summarizes the changes in the expression of common exerkines (neurotrophic factors, inflammatory factors, myokines, bioactive peptides) after SCI, and intends to analyze the impact and role of different exercise methods on functional recovery after SCI from the perspective of exerkines mechanism. We hope to provide theoretical basis and data support for scientific exercise treatment programs after SCI.

How Can Promoting Skeletal Muscle Health and Exercise in Children and Adolescents Prevent Insulin Resistance and Type 2 Diabetes?

Skeletal muscle secretome, through its paracrine and endocrine functions, contributes to the maintenance and regulation of overall physiological health. We conducted a narrative review on the role of skeletal muscle and exercise in maintaining glucose homeostasis, driving insulin resistance (IR), and preventing type 2 diabetes in pediatric populations, especially in the context of overweight and obesity. Myokines such as interleukin (IL)-6, IL-8, and IL-15, as well as irisin, myonectin, and myostatin, appear to play a crucial role in IR. Skeletal muscle can also become a target of obesity-induced and IR-induced inflammation. In the correlation between muscle, IR, and inflammation, the role of infiltration of the immune cells and the microvasculature may also be considered. It remains unclear which exercise approach is the best; however, combining aerobic exercise with resistance training seems to be the most effective strategy for managing IR, with high-intensity activities offering superior metabolic benefits and long-term adherence. Encouraging daily participation in enjoyable and engaging exercise is key for long-term commitment and effective glucose metabolism management. Promoting physical activity in children and adolescents must be a top priority for public health, not only in terms of individual quality of life and well-being but also for community health.

Exercise as a tool to mitigate metabolic disease

Metabolic diseases, notably obesity and type 2 diabetes (T2D), have reached alarming proportions and constitute a significant global health challenge, emphasizing the urgent need for effective preventive and therapeutic strategies. In contrast, exercise training emerges as a potent intervention, exerting numerous positive effects on metabolic health through adaptations to the metabolic tissues. Here, we reviewed the major features of our current understanding with respect to the intricate interplay between metabolic diseases and key metabolic tissues, including adipose tissue, skeletal muscle, and liver, describing some of the main underlying mechanisms driving pathogenesis, as well as the role of exercise to combat and treat obesity and metabolic disease.

Circulating miRNA Signaling for Fatty Acid Metabolism in Response to a Maximum Endurance Test in Elite Long-Distance Runners

Maximal oxygen uptake (VO2max) is a determining indicator for cardiorespiratory capacity in endurance athletes, and epigenetics is crucial in its levels and variability. This initial study examined a broad plasma miRNA profile of twenty-three trained elite endurance athletes with similar training volumes but different VO2max in response to an acute maximal graded endurance test. Six were clustered as higher/lower levels based on their VO2max (75.4 ± 0.9 and 60.1 ± 5.0 mL.kg-1.min-1). Plasma was obtained from athletes before and after the test and 15 ng of total RNA was extracted and detected using an SYBR-based 1113 miRNA RT-qPCR panel. A total of 51 miRNAs were differentially expressed among group comparisons. Relative amounts of miRNA showed a clustering behavior among groups regarding distinct performance/time points. Significantly expressed miRNAs were used to perform functional bioinformatic analysis (DIANA tools). Fatty acid metabolism pathways were strongly targeted for the significantly different miRNAs in all performance groups and time points (p < 0.001). Although this pathway does not solely determine endurance performance, their significant contribution is certainly achieved through the involvement of miRNAs. A highly genetically dependent gold standard variable for performance evaluation in a homogeneous group of elite athletes allowed genetic/epigenetic aspects related to fatty acid pathways to emerge.

Irisin promotes hair growth and hair cycle transition by activating the GSK-3β/β-catenin pathway

Hair loss affects men and women of all ages. Myokines, which are mainly secreted by skeletal muscles during exercise, have numerous health benefits. VEGF, IGF-1, FGF and irisin are reprehensive myokines. Although VEGF, IGF-1 and FGF are positively associated with hair growth, few studies have researched the effects of irisin on hair growth. Here, we investigated whether irisin promotes hair growth using in vitro, ex vivo and in vivo patch assays, as well as mouse models. We show that irisin increases proliferation, alkaline phosphatase (ALP) activity and mitochondrial membrane potential in human dermal papilla cells (hDPCs). Irisin activated the Wnt/β-catenin signalling pathway, thereby upregulating Wnt5a, Wnt10b and LEF-1, which play an important role in hair growth. Moreover, irisin enhanced human hair shaft elongation. In vivo, patch assays revealed that irisin promotes the generation of new hair follicles, accelerates entry into the anagen phase, and significantly increases hair growth in C57BL/6 mice. However, XAV939, a Wnt/β-catenin signalling inhibitor, suppressed the irisin-mediated increase in hair shaft and hair growth. These results indicate that irisin increases hair growth via the Wnt/β-catenin pathway and highlight its therapeutic potential in hair loss treatment.

Systemic impacts of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) on heart, muscle, and kidney related diseases

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disorder worldwide, with an estimated global prevalence of more than 31%. Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is a progressive form of MASLD characterized by hepatic steatosis, inflammation, and fibrosis. This review aims to provide a comprehensive analysis of the extrahepatic manifestations of MASH, focusing on chronic diseases related to the cardiovascular, muscular, and renal systems. A systematic review of published studies and literature was conducted to summarize the findings related to the systemic impacts of MASLD and MASH. The review focused on the association of MASLD and MASH with metabolic comorbidities, cardiovascular mortality, sarcopenia, and chronic kidney disease. Mechanistic insights into the concept of lipotoxic inflammatory "spill over" from the MASH-affected liver were also explored. MASLD and MASH are highly associated (50%-80%) with other metabolic comorbidities such as impaired insulin response, type 2 diabetes, dyslipidemia, hypertriglyceridemia, and hypertension. Furthermore, more than 90% of obese patients with type 2 diabetes have MASH. Data suggest that in middle-aged individuals (especially those aged 45-54), MASLD is an independent risk factor for cardiovascular mortality, sarcopenia, and chronic kidney disease. The concept of lipotoxic inflammatory "spill over" from the MASH-affected liver plays a crucial role in mediating the systemic pathological effects observed. Understanding the multifaceted impact of MASH on the heart, muscle, and kidney is crucial for early detection and risk stratification. This knowledge is also timely for implementing comprehensive disease management strategies addressing multi-organ involvement in MASH pathogenesis.

Suppressive effects of exercise-conditioned serum on cancer cells: A narrative review of the influence of exercise mode, volume, and intensity

Cancer is a major cause of morbidity and mortality worldwide, and the incidence is increasing, highlighting the need for effective strategies to treat this disease. Exercise has emerged as fundamental therapeutic medicine in the management of cancer, associated with a lower risk of recurrence and increased survival. Several avenues of research demonstrate reduction in growth, proliferation, and increased apoptosis of cancer cells, including breast, prostate, colorectal, and lung cancer, when cultured by serum collected after exercise in vitro (i.e., the cultivation of cancer cell lines in an experimental setting, which simplifies the biological system and provides mechanistic insight into cell responses). The underlying mechanisms of exercise-induced cancer suppressive effects may be attributed to the alteration in circulating factors, such as skeletal muscle-induced cytokines (i.e., myokines) and hormones. However, exercise-induced tumor suppressive effects and detailed information about training interventions are not well investigated, constraining more precise application of exercise medicine within clinical oncology. To date, it remains unclear what role different training modes (i.e., resistance and aerobic training) as well as volume and intensity have on exercise-conditioned serum and its effects on cancer cells. Nevertheless, the available evidence is that a single bout of aerobic training at moderate to vigorous intensity has cancer suppressive effects, while for chronic training interventions, exercise volume appears to be an influential candidate driving cancer inhibitory effects regardless of training mode. Insights for future research investigating training modes, volume and intensity are provided to further our understanding of the effects of exercise-conditioned serum on cancer cells.

Mechanisms Underlying the Rarity of Skeletal Muscle Cancers

Skeletal muscle (SKM), despite comprising ~40% of body mass, rarely manifests cancer. This review explores the mechanisms that help to explain this rarity, including unique SKM architecture and function, which prohibits the development of new cancer as well as negates potential metastasis to SKM. SKM also presents a unique immune environment that may magnify the anti-tumorigenic effect. Moreover, the SKM microenvironment manifests characteristics such as decreased extracellular matrix stiffness and altered lactic acid, pH, and oxygen levels that may interfere with tumor development. SKM also secretes anti-tumorigenic myokines and other molecules. Collectively, these mechanisms help account for the rarity of SKM cancer.

Pathophysiology of Physical Exercise in Kidney Patients: Unveiling New Players - The Role of Myokines

BACKGROUND

Chronic kidney disease (CKD) is a progressive systemic condition characterized by numerous complications. Among these, alterations in skeletal muscle physiology, such as sarcopenia, are particularly significant, as they are associated with poor outcomes and reduced quality of life.

SUMMARY

Various interventions, including pharmacological approaches and lifestyle modifications have been investigated to slow CKD progression and prevent or treat its complications. Physical exercise, in particular, has emerged as a promising intervention with multiple beneficial effects. These include improvements in physical functioning, increased muscle mass, modulation of metabolic abnormalities, and reduced cardiovascular risk. However, the pathophysiology of physical exercise in patients with kidney disease is complex and remains only partially understood. A crucial advancement in understanding this phenomenon has been the identification of myokines - molecules expressed and released by skeletal muscle in response to physical activity. These myokines can exert both paracrine and systemic effects, influencing not only skeletal muscle physiology but also other processes such as energy metabolism and lipid regulation.

KEY MESSAGES

The interplay among skeletal muscle, physical activity, and myokines may act as a pivotal regulator in various physiological processes, including aging, as well as in pathological conditions like cachexia and sarcopenia, frequently observed in CKD patients at different stages, including patients on dialysis. Despite the potential importance of this relationship, only a limited number of studies have explored the relationship between exercise and myokine, and the effect of this interaction on experimental models or individuals with kidney disease. In the following sections, we review and discuss this topic.

Effects of Resistance Exercise and Essential Amino Acid Intake on Muscle Quality, Myokine, and Inflammation Factors in Young Adult Males

BACKGROUND

Recently, many studies have been devoted to discovering nutrients for exercise-like effects. Resistance exercise and the intake of essential amino acids (EAAs) are known to be factors that can affect muscle mass and strength improvement. The purpose of this study was to investigate changes in muscle quality, myokines, and inflammation in response to resistance exercise and EAA supplementation.

METHODS

Thirty-four males volunteered to participate in this study. They were assigned to four groups: (1) placebo (CO), (2) resistance exercise (RE), (3) EAA supplementation, and (4) RE + EAA supplementation. Body composition, muscle quality, myokines, and inflammation were measured at baseline and four weeks after treatment.

RESULTS

Lean body fat had decreased in both RE and RE + EAA groups. Lean body mass had increased in only the RE + EAA group. In all groups except for CO, irisin, myostatin A, and TNF-α levels had decreased. The grip strength of the right hand and trunk flexion peak torque increased in the RE group. The grip strength of the left hand, trunk flexion peak torque, and knee flexion peak torque of the left leg were increased in RE + EAA.

CONCLUSIONS

RE, EAA, and RE + EAA could effectively improve the muscle quality, myokine, and inflammation factors of young adult males. This finding highlights the importance of resistance exercise and amino acid intake.

IGF1 promotes human myotube differentiation toward a mature metabolic and contractile phenotype

Skeletal muscle mediates the beneficial effects of exercise, thereby improving insulin sensitivity and reducing the risk for type 2 diabetes. Current human skeletal muscle models in vitro are incapable of fully recapitulating its physiological functions especially muscle contractility. By supplementation of insulin-like growth factor 1 (IGF1), a growth factor secreted by myofibers in vivo, we aimed to overcome these limitations. We monitored the differentiation process starting from primary human CD56-positive myoblasts in the presence/absence of IGF1 in serum-free medium in daily collected samples for 10 days. IGF1-supported differentiation formed thicker multinucleated myotubes showing physiological contraction upon electrical pulse stimulation (EPS) following day 6. Myotubes without IGF1 were almost incapable of contraction. IGF1 treatment shifted the proteome toward skeletal muscle-specific proteins that contribute to myofibril and sarcomere assembly, striated muscle contraction, and ATP production. Elevated PPARGC1A, MYH7, and reduced MYH1/2 suggest a more oxidative phenotype further demonstrated by higher abundance of proteins of the respiratory chain and elevated mitochondrial respiration. IGF1-treatment also upregulated glucose transporter (GLUT)4 and increased insulin-dependent glucose uptake compared with myotubes differentiated without IGF1. To conclude, addition of IGF1 to serum-free medium significantly improves the differentiation of human myotubes that showed enhanced myofibril formation, response to electrical pulse stimulation, oxidative respiratory capacity, and glucose metabolism overcoming limitations of previous standards. This novel protocol enables investigation of muscular exercise on a molecular level.NEW & NOTEWORTHY Human skeletal muscle models are highly valuable to study how exercise prevents type 2 diabetes without invasive biopsies. Current models did not fully recapitulate the function of skeletal muscle especially during exercise. By supplementing insulin-like growth factor 1 (IGF1), the authors developed a functional human skeletal muscle model characterized by inducible contractility and increased oxidative and insulin-sensitive metabolism. The novel protocol overcomes the limitations of previous standards and enables investigation of exercise on a molecular level.

The mediating role of lower body muscle strength and IGF-1 level in the relationship between age and cognition. A MIDUS substudy

OBJECTIVE

Aging is a natural process associated with a decline in cognition. However, the mediating effect of physical function and circulating myokines on this relationship has yet to be fully clarified. This study investigated how muscle strength and circulating insulin-like growth factor-1 (IGF-1) levels mediate the relationship between age and cognitive functions.

SUBJECTS AND METHODS

A total of 1255 participants aged 25-74 years included in the Midlife in the United States II study were retrospectively analyzed. In this cross-sectional analysis, we applied a serial mediation model to explore the mediating effects of muscle strength and circulating IGF-1 levels on the relationship between age and cognitive functions. We included potential confounding factors related to sociodemographics, lifestyle, and health status as covariates in the model.

RESULTS

The results showed that aging had both direct and indirect effects on cognition. As predicted, muscle strength and IGF-1 levels mediated the relationship between age and specific cognitive functions. In addition, mediation analyses indicated that the association between aging and cognitive flexibility, immediate and delayed memory, and inductive reasoning were partially mediated by muscle strength and IGF-1 levels in a serial manner.

CONCLUSIONS

Our study demonstrated the serial multiple mediation roles of muscle strength and IGF-1 levels on the relationship between age and specific cognitive functions. Further longitudinal research should be performed to confirm the serial mediation results.

Concurrent Resistance and Cardiorespiratory Training in Patients with Hypertrophic Cardiomyopathy: A Pilot Study

Background: Exercise training in patients with HCM has evidenced benefits on functional capacity, cardiac function, and a reversion of adverse cardiac remodeling. The objective of this study was to assess the effect of a concurrent resistance and cardiorespiratory training program on functional capacity, biochemical parameters, and echocardiographic variables in a pilot group. Methods: Two HCM patients were evaluated before and after 12 weeks of individualized concurrent training with two sessions/week. Pre- and post-training data were compared for each patient. Evaluations included a cardiopulmonary exercise test (CPET), body composition, echocardiography, electrocardiography, and blood analysis. Results: Training promoted an increase in functional capacity (+4 mL·kg-1·min-1), ventilatory thresholds, and other CPET-derived variables associated with a better prognosis and long-term survival. Muscular mass was augmented (0.8 and 1.2 kg), along with a mean increase of 62% in upper and lower body strength. Echocardiographic features demonstrated the maintenance of cardiac function with signs of positive left ventricular remodeling and an improvement in diastolic function. Blood analyses, including cardiac troponins and NT-proBNP, displayed uneven changes in each patient, but the values fell into normal ranges in both cases. Conclusions: The available data suggest a positive effect of concurrent resistance and cardiorespiratory training on patients' functional capacity and cardiac function that may improve their functional class, quality of life, and long-term prognosis. The replication of this protocol in a larger cohort of patients is warranted to confirm these preliminary results.

New role of fat-free mass in cancer risk linked with genetic predisposition

Cancer risk is associated with the widely debated measure body mass index (BMI). Fat mass and fat-free mass measurements from bioelectrical impedance may further clarify this association. The UK Biobank is a rare resource in which bioelectrical impedance and BMI data was collected on ~ 500,000 individuals. Using this dataset, a comprehensive analysis using regression, principal component and genome-wide genetic association, provided multiple levels of evidence that increasing whole body fat (WBFM) and fat-free mass (WBFFM) are both associated with increased post-menopausal breast cancer risk, and colorectal cancer risk in men. WBFM was inversely associated with prostate cancer. We also identified rs615029[T] and rs1485995[G] as associated in independent analyses with both PMBC (p = 1.56E-17 and 1.78E-11) and WBFFM (p = 2.88E-08 and 8.24E-12), highlighting splice variants of the intriguing long non-coding RNA CUPID1 (LINC01488) as a potential link between PMBC risk and fat-free mass.

Secretome from Magnetically Stimulated Muscle Exhibits Anticancer Potency: Novel Preconditioning Methodology Highlighting HTRA1 Action

Briefly (10 min) exposing C2C12 myotubes to low amplitude (1.5 mT) pulsed electromagnetic fields (PEMFs) generated a conditioned media (pCM) that was capable of mitigating breast cancer cell growth, migration, and invasiveness in vitro, whereas the conditioned media harvested from unexposed myotubes, representing constitutively released secretome (cCM), was less effective. Administering pCM to breast cancer microtumors engrafted onto the chorioallantoic membrane of chicken eggs reduced tumor volume and vascularity. Blood serum collected from PEMF-exposed or exercised mice allayed breast cancer cell growth, migration, and invasiveness. A secretome preconditioning methodology is presented that accentuates the graded anticancer potencies of both the cCM and pCM harvested from myotubes, demonstrating an adaptive response to pCM administered during early myogenesis that emulated secretome-based exercise adaptations observed in vivo. HTRA1 was shown to be upregulated in pCM and was demonstrated to be necessary and sufficient for the anticancer potency of the pCM; recombinant HTRA1 added to basal media recapitulated the anticancer effects of pCM and antibody-based absorption of HTRA1 from pCM precluded its anticancer effects. Brief and non-invasive PEMF stimulation may represent a method to commandeer the secretome response of muscle, both in vitro and in vivo, for clinical exploitation in breast and other cancers.

Sarcopenic obesity in cancer

BACKGROUND

Sarcopenic obesity is a relatively new term. It is a clinical condition characterized by sarcopenia (loss of muscle mass and function) and obesity (increase in fat mass) that mainly affects older adults. As the incidence of sarcopenia and obesity increases worldwide, sarcopenic obesity is becoming a greater problem also in cancer patients. In fact, sarcopenic obesity is associated with poorer treatment outcomes, longer hospital stays, physical disability, and shorter survival in several cancers. Oxidative stress, lipotoxicity, and systemic inflammation, as well as altered expression of skeletal muscle anti-inflammatory myokines in sarcopenic obesity, are also associated with carcinogenesis.

CONCLUSIONS

Reported prevalence of sarcopenic obesity in cancer varies because of heterogeneity in definitions and variability in diagnostic criteria used to estimate the prevalence of sarcopenia and obesity. Therefore, the aim of this review is to describe the definitions, prevalence, and diagnostic criteria as well as the mechanisms that cancer has in common with sarcopenic obesity.

Advancing cancer cachexia diagnosis with -omics technology and exercise as molecular medicine

Muscle atrophy exacerbates disease outcomes and increases mortality, whereas the preservation of skeletal muscle mass and function play pivotal roles in ensuring long-term health and overall quality-of-life. Muscle atrophy represents a significant clinical challenge, involving the continued loss of muscle mass and strength, which frequently accompany the development of numerous types of cancer. Cancer cachexia is a highly prevalent multifactorial syndrome, and although cachexia is one of the main causes of cancer-related deaths, there are still no approved management strategies for the disease. The etiology of this condition is based on the upregulation of systemic inflammation factors and catabolic stimuli, resulting in the inhibition of protein synthesis and enhancement of protein degradation. Numerous necessary cellular processes are disrupted by cachectic pathology, which mediate intracellular signalling pathways resulting in the net loss of muscle and organelles. However, the exact underpinning molecular mechanisms of how these changes are orchestrated are incompletely understood. Much work is still required, but structured exercise has the capacity to counteract numerous detrimental effects linked to cancer cachexia. Primarily through the stimulation of muscle protein synthesis, enhancement of mitochondrial function, and the release of myokines. As a result, muscle mass and strength increase, leading to improved mobility, and quality-of-life. This review summarises existing knowledge of the complex molecular networks that regulate cancer cachexia and exercise, highlighting the molecular interplay between the two for potential therapeutic intervention. Finally, the utility of mass spectrometry-based proteomics is considered as a way of establishing early diagnostic biomarkers of cachectic patients.