Muscle, Bone, and Fat Crosstalk: the Biological Role of Myokines, Osteokines, and Adipokines

Exercise alleviates osteoporosis by regulating the secretion of the Senescent Associated Secretory Phenotype

As the elderly population grows, the number of patients with metabolic bone diseases such as osteoporosis has increased sharply, posing a significant threat to public health and social economics. Although pharmacological therapies for osteoporosis demonstrate therapeutic benefits, their prolonged use is associated with varying degrees of adverse effects. As a non-pharmacological intervention, exercise is widely recognized for its cost-effectiveness, safety, and lack of toxic side effects, making it a recommended treatment for osteoporosis prevention and management. Previous studies have demonstrated that exercise can improve metabolic bone diseases by modulating the Senescent Associated Secretory Phenotype (SASP). However, the mechanisms through which exercise influences SASP remain unclear. Therefore, this review aims to summarize the effects of exercise on SASP and elucidate the specific mechanisms by which exercise regulates SASP to alleviate osteoporosis, providing a theoretical basis for osteoporosis through exercise and developing targeted therapies.

Bone and muscle crosstalk in ageing and disease

Interorgan communication between bone and skeletal muscle is central to human health. A dysregulation of bone-muscle crosstalk is implicated in several age-related diseases. Ageing-associated changes in endocrine, inflammatory, nutritional and biomechanical stimuli can influence the differentiation capacity, function and survival of mesenchymal stem cells and bone-forming and muscle-forming cells. Consequently, the secretome phenotype of bone and muscle cells is altered, leading to impaired crosstalk and, ultimately, catabolism of both tissues. Adipose tissue acts as a third player in the bone-muscle interaction by secreting factors that affect bone and muscle cells. Physical exercise remains the key biological stimulus for bone-muscle crosstalk, either directly via the release of cytokines from bone, muscle or adipocytes, or indirectly through extracellular vesicles. Overall, bone-muscle crosstalk is considered an inherent process necessary to maintain the structure and function of both tissues across the life cycle. This Review summarizes the latest biomedical advances in bone-muscle crosstalk as it pertains to human ageing and disease. We also outline future research priorities to accommodate the understanding of this rapidly emerging field.

The bone-muscle unit: from mechanical coupling to soluble factors-mediated signaling

Skeletal muscles (SKM) and bones form a morpho-functional unit, interconnected throughout life primarily through biomechanical coupling. This relationship serves as a key reciprocal stimulus, but they also interact via various hormones, such as sex steroids, growth hormone-insulin-like growth factor 1 (GH-IGF1) axis hormones, and adipokines like leptin and adiponectin. Additionally, myokines (released by muscles) and osteokines (released by bones) facilitate dense crosstalk, influencing each other's activity. Key myokines include interleukin (IL)-6, IL-7, IL-15, and myostatin, while osteocalcin (OC) and sclerostin are crucial bone-derived mediators affecting SKM cells. Moreover, miRNAs act as endocrine-like regulators, contributing to a complex network. This review covers the current understanding of bone-muscle crosstalk, which is essential for grasping the musculoskeletal apparatus's role in disease pathogenesis and may inform therapeutic development.

HBP-A Attenuates Knee Osteoarthritis Progression via MLK3/P38/HDAC4 Axis-Mediated Dual Protection of Articular Cartilage and Quadriceps

Knee osteoarthritis (KOA), a degenerative joint disease driven by biomechanical instability, involves cartilage degradation, muscle dysfunction, and MLK3/P38 MAPK pathway activation. Histone deacetylase 4 (HDAC4), a regulator of chondrocyte and muscle homeostasis, interacts with this pathway during disease progression. While Hyriopsis Bioactive Polysaccharide-Anodonta (HBP-A) exhibits P38 MAPK inhibitory properties in vitro, its in vivo therapeutic effects on musculoskeletal tissues remain uncharacterised. A destabilisation of the medial meniscus (DMM) mouse model was established to investigate HBP-A's therapeutic potential. Animals were randomly divided into sham-operated, DMM-induced, and HBP-A-treated groups. Following surgical induction, HBP-A (0.26 g/kg) was administered daily via oral gavage for 4 weeks. Comprehensive assessments included behavioural tests for pain sensitivity, micro-CT scanning, histological evaluation, and transmission electron microscope. Molecular mechanisms were investigated via immunohistochemical or immunofluorescence staining of MLK3, P38 MAPK, Caspase-3, and HDAC4, complemented by RT-qPCR analysis of myokine expression. HBP-A treatment significantly alleviated pain sensitivity compared to the DMM group. Structural evaluations revealed preserved subchondral bone integrity and attenuated cartilage degeneration, with histological scoring confirming reduced pathological changes. Quadriceps exhibited mitigated atrophy and restored ultrastructural organisation. Molecular profiling demonstrated suppressed MLK3/P38 MAPK pathway activation, diminished apoptotic activity, and elevated HDAC4 expression in both cartilage and quadriceps. HBP-A additionally normalised dysregulated expression of muscle-derived osteogenic factors linked to bone-cartilage crosstalk. These findings establish HBP-A as a dual-target therapeutic agent for KOA, concurrently mitigating cartilage and muscle degeneration through MLK3/P38 MAPK/HDAC4 axis modulation.

Higher serum resistin levels and increased frailty risk in older adults: Implications beyond metabolic function

BACKGROUND

Despite the pleiotropic role of resistin as an adipokine, its association with frailty-an indicator of biologic age and overall well-being in humans-remains largely unexplored. This study aims to investigate the potential of circulating resistin as a biomarker for frailty.

METHODS

The study included 228 older adults aged 65 years or older who underwent a comprehensive geriatric assessment. Frailty was evaluated using both the phenotypic frailty model by Fried and the deficit-accumulation frailty index (FI) by Rockwood. Serum resistin levels were measured using a competitive enzyme-linked immunosorbent assay.

RESULTS

After adjusting for sex, age, body mass index, smoking, alcohol, exercise, diabetes, and serum creatinine, serum resistin levels were 52.2% higher in individuals with phenotypic frailty than in robust controls (P =  0.001) and showed a positive correlation with the Rockwood FI (P =  0.015). Furthermore, for every 1 standard deviation increase in serum resistin levels, the risk of frailty increased by 67% (P =  0.021). When participants were divided into four groups based on serum resistin levels, individuals in the highest quartile had a 38% higher FI and exhibited a 12.5-fold higher odds ratio for frailty compared to those in the lowest quartile (P =  0.016 and 0.024, respectively).

CONCLUSION

These findings suggest that circulating resistin may serve as a candidate blood-based biomarker for frailty, encompassing the multifaceted physical, cognitive, and social dimensions, extending beyond its well-established role in metabolic regulation.

Body composition as an index of the trabecular bone score in postmenopausal women

OBJECTIVE

Obesity is considered to exert a protective effect on bone mineral density (BMD). However, emerging data indicate that the effect of adipose tissue on bone health is much more complex. Trabecular bone score (TBS) provides information on bone texture and predicts fracture risk independently of BMD. This study investigated the association of body composition and bone quality as evaluated by lumbar spine (LS) TBS.

STUDY DESIGN

Cross-sectional study including 118 postmenopausal women (mean age 60.73 ± 8.97 years and mean BMI 28.36 ± 5.8) with no history of secondary osteoporosis or previous anti-osteoporotic treatment.

MAIN OUTCOME MEASURES

Body composition, BMD and LS TBS were evaluated by dual-energy X-ray absorptiometry (DXA). Τo explore the associations among the variables of interest, Spearman's correlations were used. Simple and multiple linear regression models were also applied to explore the associations among variables of interest.

RESULTS

Visceral adipose tissue (VAT) mass, android fat mass and android/gynoid fat ratio were negative predictors of TBS (Stb = -0.413, p < 0.001; Stb = -0.369, p < 0.001; Stb = -0.333, p < 0.001, respectively). Similarly, both the right (Stb = -0.313, p < 0.001) and left arm fat mass (Stb = -0.313, p < 0.001) were negative predictors of TBS. In a multiple linear regression model, VAT mass exhibited a significant negative association with TBS (Stb = -0.415, p < 0.05).

CONCLUSIONS

The present study offers evidence that VAT mass has a negative association with bone texture as estimated by TBS in postmenopausal women. Moreover, the findings suggest that the body composition of the arms (arm fat mass) correlates inversely with the bone texture. Further research is required to validate these findings in large cohorts of postmenopausal women.

Prevention of glucocorticoid-induced impairment of bone metabolism-a randomized, placebo-controlled, single centre proof-of-concept clinical trial

Oral glucocorticoid (GC) therapy rapidly and deleteriously affects bone metabolism and blood glucose regulation. The gut microbiota regulates bone metabolism and a prior study found that Limosilactobacillus reuteri ATCC PTA6475 (L. reuteri) reduced bone loss over 12 mo in older women. Mice treated either with broad-spectrum antibiotics or with L. reuteri did not experience GC-induced trabecular bone loss. This proof-of-concept, randomized, double-blind, placebo-controlled trial aimed to investigate if daily supplementation with L. reuteri, compared with placebo, could mitigate or prevent the negative effects of oral GC on bone turnover and blood glucose regulation in healthy young adults. Twenty-one men and 29 women, aged 18-45, were randomized to either placebo or L. reuteri (1 × 1010 CFU/d) treatment for 2 wk, followed by open-label oral prednisolone 25 mg daily for 7 d. Primary outcomes were changes in blood bone status indices (osteocalcin, C-terminal telopeptide cross-links of collagen type-I (CTX), and type-I procollagen intact N-terminal propeptide [PINP]) from baseline to 7 d after starting oral GC. Secondary endpoints included changes in blood glucose levels using continuous glucose monitoring during the same period (ClinicalTrials.gov NCT04767711). Blood samples were collected from participants in the morning after overnight fasting. Forty-six participants completed the 30-d study. The L. reuteri and placebo groups were well balanced in terms of baseline characteristics (age, BMI, sex, dietary intake, and physical activity). No significant differences were found between L. reuteri vs placebo for percent changes in CTX (-0.3 [95%CI -19.2-18.7], p = .98) or PINP (4.2 [-6.3-14.8], p = .43), or in osteocalcin levels (14.2 [-7.8-36.3], p = .21), although the group-to-group difference in osteocalcin was larger. There was no effect of treatment on mean blood glucose (-0.1 [-0.3-0.1] mmol/L, p = .28). In conclusion, we failed to detect a significant effect of L. reuteri supplementation on GC-related adverse effects on bone status indices in this proof-of-concept RCT. Larger studies are needed to identify any potential smaller effects.

Role of Inflammatory Biomarkers in Mediating Causal Effect of Life Course Body Composition on Hypertension

BACKGROUND

The mediating role of inflammatory biomarkers in the causal relationship between body composition and hypertension remains unclear and requires further investigation.

METHODS

This study used a combination of retrospective observational analysis and Mendelian randomization approaches. Observational data were derived from 4717 Chinese children and adolescents aged 6 to 18 years who underwent dual-energy X-ray absorptiometry to assess body composition. Mendelian randomization analyses utilized summary statistics from large-scale data sets, including UK Biobank, deCODE2021, International Consortium of Blood Pressure, FinnGen, and other consortia. The inflammatory biomarkers included leptin, insulin, adiponectin, osteocalcin, FGF23 (fibroblast growth factor 23), and PTH (parathyroid hormone).

RESULTS

The observational analysis revealed that increased fat mass positively influenced diastolic blood pressure through osteocalcin, while fat-free mass had an inverse effect. Insulin mediated the association between fat mass and systolic blood pressure, diastolic blood pressure, and hypertension, with additional indirect effects observed for PTH (all P<0.05). The Mendelian randomization analyses demonstrated a causal relationship between childhood body mass index and hypertension mediated by insulin (indirect effect: odds ratio, 0.87 [95% CI, 0.78-0.97]) and adiponectin (odds ratio, 1.13 [95% CI, 1.04-1.23]). Adiponectin mediated the effects of fat-free mass (odds ratio, 0.81 [95% CI, 0.71-0.93]) and fat mass (odds ratio, 1.30 [95% CI, 1.11-1.51]) on hypertension. Leptin, adiponectin, and insulin also mediated the causal effects of body composition on systolic blood pressure, diastolic blood pressure, and hypertension.

CONCLUSIONS

These findings indicate that body composition influences blood pressure through distinct inflammatory biomarkers. Targeting inflammatory biomarkers may provide tailored strategies for managing body composition and hypertension.

Evaluating lower limits of body fat percentage in athletes using DXA

Body fat percentage (BF%) is routinely measured in athletes to monitor training and dietary interventions. Dual energy x-ray absorptiometry (DXA) is widely considered the gold standard body composition measurement technique, but DXA BF% values measure consistently higher than other techniques. Therefore, the main purpose of this study is to determine the lowest DXA-estimated whole-body fat mass in free-living athletes with unrestricted access to food. In this cross-sectional analyses, 732 participants across 18 competitive sports (643 athletes; 88 %) plus two (male and female) "non-athlete" male and female cohorts (89 non-athletes; 12 %) underwent a whole-body DXA scan using a Horizon A Hologic™ device (software version 13.6.0.5; TBAR 1209), performed and analyzed by a single operator. The average BF % in 454 males (20.9 ± 3.8 years) was 18.2 ± 4.9 % (range 10.3 - 37.2 %), with basketball players having the lowest BF% (15.3 ± 2.6 %) and non-athletes having the highest BF% (21.6 ± 5.4 %) (1-way ANOVA between 10 teams: F = 12.3; p < 0.0001). The average BF% in 278 females (21.3 ± 5.5 years) was 27.1 ± 5.1 % (range 16.2 - 45.3 %), with runners having the lowest BF% (23.5 ± 3.5 %) and non-athletes having the highest BF% (31.7 ± 6.3 %) (1-way ANOVA between 10 teams F = 12.9; p < 0.0001). In absolute values (kg), the average body fat for males was 19.9 ± 8.0 kg (range 6.7 - 62.0 kg) and 18.9 ± 6.4 kg (range 9.2 - 49.7 kg) for females. These data suggest that the lower limits of whole-body fat mass in free-living competitive athletes is approximately 10 % for males and 16 % for females. Whether these DXA-derived fat thresholds represent "healthy" levels, or how much of these DXA-derived fat depots represent essential fat stores located within lean soft tissue mass, remains unclear.

Aging: A struggle for beneficial to overcome negative factors made by muscle and bone

Musculoskeletal health is strongly influenced by regulatory interactions of bone and muscle. Recent discoveries have identified a number of key mechanisms through which soluble factors released during exercise by bone exert positive effects on muscle and by muscle on bone. Although exercise can delay the negative effects of aging, these beneficial effects are diminished with aging. The limited response of aged muscle and bone tissue to exercise are accompanied by a failure in bone and muscle communication. Here, we propose that exercise induced beneficial factors must battle changes in circulating endocrine and inflammatory factors that occur with aging. Furthermore, sedentary behavior results in the release of negative factors impacting the ability of bone and muscle to respond to physical activity especially with aging. In this review we report on exercise responsive factors and evidence of modification occurring with aging.

Osteosarcopenia and geriatric hip fractures: Current concepts

According to World Health Organization, one in six people will be older than 60 by 2030. The rising life expectancy is anticipated to contribute to a subsequent increase of geriatric fractures worldwide. Osteosarcopenia, which is the coexistence of osteoporosis and sarcopenia, greatly affects older people. Recent studies have tried to identify the prevalence of osteosarcopenia in older populations as well as its correlation with fragility fractures such as hip fractures. The latter pose a major burden on both health loss and costs worldwide. Increasing amount of evidence suggests that osteosarcopenia in patients with hip fractures contributes to higher rates of mortality and complications. At the same time, research focuses on the molecular basis of the interplay between osteoporosis and sarcopenia by utilizing genomic or proteomic approaches. These promising studies could reveal potential preventive or diagnostic biomarkers to optimize the management of osteosarcopenia in hip fractures patients. The fact that bones and muscle can also function as endocrine organs further highlights the complex relationship between osteoporosis and sarcopenia, underscoring the need for a better understanding of the role of myokines and osteokines in osteosarcopenia. Finally, the impact of osteosarcopenia on pain management and rehabilitation after hip fracture surgery, requires further assessment.

Osteogenesis Differentiation and Molecular Mechanism Study of a Si and Mg Dual-Ion System Based on mRNA Transcriptomic Sequencing Analysis

Both silicon (Si) and magnesium (Mg) ions play essential roles in bone health. However, the precise mechanisms by which these two ions enhance osteogenic differentiation remain to be fully elucidated. Herein, a Si-Mg dual-ion system was designed to investigate the effects of Si and Mg ions on the cytological behavior of mouse bone marrow mesenchymal stem cells (mBMSCs). The molecular mechanism of the Si-Mg dual-ion system regulating osteogenic differentiation of mBMSCs was investigated by transcriptome sequencing technology. In the single-ion system, the Si group with concentrations of 1.5 and 0.75 mM exhibited good combined effects (cell proliferation, alkaline phosphatase (ALP) activity, and osteogenic differentiation gene expression (Runx2, OPN, and Col-I)) of mBMSCs. The Mg group with concentrations of 5 and 2.5 mM showed better combined effects (cell proliferation, ALP activity, and osteogenic differentiation gene expression) of mBMSCs. In the dual-ion system, the silicon (0.75 mM)-magnesium (2.5 mM) experimental group significantly enhanced the proliferation, ALP activity, and osteogenesis-related gene expression (Runx2, OPN, and Col-I) of mBMSCs. The analysis of transcriptome sequencing results showed that Mg ions had a certain pro-stem cell osteogenic differentiation regulatory effect. Si ions had a stronger regulation on osteogenic differentiation than the Mg ions. The regulation of osteogenic differentiation by Si-Mg dual ions was synergistically enhanced compared to that of a single ion. In addition, the transforming growth factor beta (TGF-β) signaling pathway and mitogen-activated protein kinase (MAPK) signaling pathway were involved in mediating the pro-stem cell osteogenic differentiation by Si-Mg dual ions. This study sheds light on investigating the molecular mechanism of dual-ion regulation of the osteogenic differentiation of mBMSCs and enriches the theory of ion-regulating osteogenic differentiation.

Novel biomarkers in bone pathophysiology: Establishing reference intervals and biological variations estimates for serum leptin, sclerostin, lipocalin-2, osteoprotegerin, resistin and Dickkopf-related protein-1 from the European biological variation study (EuBIVAS) populations

A range of biomarkers of bone metabolism are thought to mediate adipose tissue-bone crosstalk and fulfil a homeostatic role. While considered clinically relevant, their utility and application appears limited by lack of data characterising biological variability and reference intervals rather than by analytical issues. We have therefore studied the biological variation (BV) of these biomarkers. Concentrations of Dikkopf-related protein 1, leptin, osteoprotegerin, sclerostin, lipocalin2 (Lcn2) and resistin were measured by Luminex assays in serum samples from the EuBIVAS study. Samples were taken once per week, over 10 consecutive weeks, from 91 subjects in cohorts from 5 European countries. Estimates of analytical variation (CVA), within-subject (CVI) and between-subject (CVG) BV were calculated and analytical imprecision (CVAPS) and analytical bias (BAPS) specifications, index of individuality (II), reference change values (RCV) for increase and decrease and the number of samples required to estimate the homeostatic set points (NHSPs) were derived. Mean concentrations differed between males and females for leptin, osteoprotegerin, and sclerostin, and for osteoprotegerin and sclerostin between females in fertile and menopausal ages. No male-to-female differences were observed in CVI estimates. Index of individuality was below 0.6, for all measurands. Determination of reference intervals (RI) limits indicated that all, with the exception Lcn2, described data which were non-gaussian distributed and that only leptin differed between sexes. Availability of high-quality biological variation enables objective assessment of the bone metabolism biomarker results which may enhance their clinical utility. The data indicates that they exhibit significant individuality.

Effect of Resistance Training on Older Adults with Sarcopenic Obesity: A Comprehensive Systematic Review and Meta-Analysis of Blood Biomarkers, Functionality, and Body Composition

Background/Objectives: Sarcopenic obesity (SO) is a clinical condition in which there is an excess of fat mass and a loss of muscle mass, strength, and function. Its prevalence increases with age, particularly in adults over 65 years old. However, debate persists on the definition and assessment of SO. The purpose of this review is to examine the impact of resistance training on older adults with sarcopenic obesity. Methods: This review included studies investigating the effects of resistance training interventions in older adults with SO. A comprehensive literature search was conducted across six databases (PubMed, SCOPUS, Cochrane Library, Embase, EBSCO, and Web of Science), yielding 1882 articles. The risk of bias in the included studies was assessed using the PEDro scale and the GRADE system. Results: Eleven randomized clinical trials were analyzed qualitatively and nine were analyzed quantitatively. The meta-analysis demonstrated that exercise interventions revealed the positive effects of exercise mainly on physical performance ([SMD] = 0.36, [95% CI] = 0.03, 0.69, p = 0.003) and body composition ([SMD] = 0.35, [95% CI] = 0.12, 0.57, p = 0.003), with no significant differences in biomarkers ([SMD] = 0.1, [95% CI] = -0.28, 0.49, p = 0.52). Conclusions: Resistance training benefits older adults with SO, improving body composition and physical function, whereas there were no significant differences in blood biomarkers. The present review highlights the limitations of the existing evidence base. Many included studies exhibited methodological shortcomings, necessitating the cautious interpretation of findings. Future research should prioritize rigorous study designs, including larger sample sizes and extended follow-up periods, to enhance the precision and generalizability of results.

Nutrition and Physical Activity in Musculoskeletal Health

A balanced diet and regular physical activity are essential for maintaining musculoskeletal health. Key nutrients such as calcium, vitamin D, and protein are especially important for preventing falls and fractures. While the benefits of these nutrients are well-established, other dietary components have not been studied as extensively. For instance, vegetables, which are rich in nutrients vital for muscle and bone health, play a crucial role in preventing falls and fractures. Over recent decades, a great emphasis has been given to the combinations of nutrients and foods in dietary patterns that may have synergistic or antagonistic effects. Despite the challenges in researching the impact of nutrition and physical activity on musculoskeletal health due to the extensive heterogeneity of the results, healthcare professionals should continue to promote healthy eating and regular physical activity, and these principles should be emphasized in public health initiatives. Ultimately, a sufficient and balanced diet, abundant in plant-based foods and low in processed or discretionary foods, along with consistent physical activity, remains the most effective strategy for the prevention of musculoskeletal issues. This article aims to review the updated literature of recent years on the links between nutrition and physical activity with bone and skeletal muscle health.

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.

Longitudinal assessment of changes in muscle composition using proton density fat fraction and T2* in patients with and without incidental vertebral compression fractures

Objective

Chemical shift encoded-based water-fat separation magnetic resonance imaging (CSE-MRI) is an emerging noninvasive tool for the assessment of bone and muscle composition. This study aims to examine both the predictive value and the longitudinal change of proton density fat fraction (PDFF) and T2* in the paraspinal muscles (PSM) in patients with and without the development of an incidental vertebral compression fracture (VCFs) after 6 months of follow-up.

Methods

Patients (N=56) with CT and 3T CSE-MRI of the lumbar spine at baseline and CSE-MRI at 6 months follow-up were included in this retrospective study. Patients who, on average, developed an incidental VCF one year after baseline MRI (VCF: N=14, 9 males, 66.8 ± 7.9 years) were frequency matched by age and sex to patients without VCFs (non-VCF) at baseline and follow-up (non-VCF: N=42, 27 males, 64.6 ± 13.3 years). Mean PDFF, T2*, and cross-sectional area (CSA) values from the autochthonous PSM of the thoracolumbar spine (T11-L4) and opportunistic CT-based bone mineral density (BMD) measurements were obtained for each individual. The associations between baseline measurements, longitudinal changes in PDFF, T2*, CSA of the PSM and the occurrence of VCFs at follow-up were evaluated using linear and logistic multivariable regression models. ROC analyses were used to assess cutoff values for predicting the development of VCFs.

Results

No significant difference in PDFF of the PSM was found between the VCF and non-VCF group at baseline (VCF/non-VCF 8.5 ± 13.8% vs. 5.0 ± 4.6%; p=0.53). In multivariable linear regression models adjusted for sex, age and baseline BMD, PDFF values of the PSM increased significantly over 6 months in the VCF group (2.4 ± 2.8% vs. -1.0 ± 2.3%, p<0.001), while T2* values of the PSM showed a significant decrease (p ≤ 0.01). ROC analyses identified a PDFF increase of 0.2% in the PSM as the optimal cutoff value to distinguish between patients with and without VCF (AUC 0.86, 95% CI [0.74-0.98], p<0.001).

Conclusion

Longitudinal PDFF-based assessment of the PSM composition may be a useful indicator for the prediction of the development of vertebral compression fractures.

Liver function linked to bone health: A bibliometric of the liver-bone axis

BACKGROUND

The liver exerts profound influence on skeletal health, while osseous tissues reciprocally modulate hepatic function. This bidirectional metabolic axis between these two organ systems plays a pivotal role in both physiological homeostasis and pathological states.

AIM

To investigate and analyze the literatures on liver-bone axis using bibliometrics.

METHODS

A comprehensive literature search pertaining to the liver-bone axis was conducted using the Science Citation Index Expanded within the Web of Science Core Collection. Subsequently, visualization and bibliometric analyses were performed utilizing VOSviewer (version 1.6.20), Citespace (version 6.2.R4), and the R programming language.

RESULTS

This comprehensive analysis encompasses 855 publications, comprising 694 articles and 161 reviews, authored by 4988 researchers from 425 institutions across 61 countries. The United States and China emerge as the leading nations in terms of publication volume. The University of California system stands out as the most influential institution in liver-bone axis research. Guanabens N is identified as the most prolific author in this field. The annual increase in publications related to the liver-bone axis underscores its growing prominence as a research focus. The study highlights key areas of investigation, including osteoporosis, bone metabolism, non-alcoholic fatty liver disease, and insulin-like growth factor-1, which represent both current and prospective hot topics within this domain.

CONCLUSION

This investigation employs bibliometric methodologies to conduct a systematic analysis of liver-bone axis literature spanning from 2001 to 2024. The exponential growth in publications over the past two decades underscores the significance of synthesizing research outcomes in this domain. Through rigorous statistical analyses, we delineate fundamental contributions to the field while providing strategic direction for emerging scholars. Furthermore, we illuminate current research trajectories and identify promising future investigative directions. Investigation of the liver-bone axis enhances our comprehension of inter-organ communication networks. Conceptualizing these organs as an integrated system provides profound insights into pathophysiological mechanisms and disease management strategies. This paradigm not only facilitates the development of sophisticated diagnostic modalities but also catalyzes the discovery of novel therapeutic agents targeting these mechanistic pathways, thereby advancing our capacity to diagnose and treat hepatic and skeletal disorders.

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

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

Serum A20 level is associated with bone mineral density in male patients with type 2 diabetes mellitus

Background

A20, also known as TNF-α-induced protein 3 (TNFAIP3), is a crucial negative regulator of inflammation and immune responses. Emerging evidence suggests that A20 is involved in the regulation of glucose metabolism and plays a significant role in bone metabolic diseases by inhibiting nuclear factor (NF)-κB activation. However, the potential relationship between serum A20 level and bone mineral density (BMD) in patients with type 2 diabetes mellitus (T2DM) has not been explored. This study aims to investigate the association between serum A20 level with BMD and bone turnover markers (BTMs) in patients with T2DM.

Method

A total of 189 patients with T2DM and 183 non-diabetic individuals were included in the study based on the inclusion and exclusion criteria. Participants were categorized into normal BMD and low BMD groups. Baseline clinical histories were collected through face-to-face questionnaires. Participants underwent measurements of blood biochemistry and anthropometric, hand grip strength records and short physical performance battery (SPPB) assessment. Serum A20 level was quantified by enzyme-linked immunosorbent assay kit. Areal BMD was measured using dual-energy x-ray absorptiometry (DXA). A T-score of less than -1.0 at the lumbar spine 1-4, femoral neck and/or total hip was classified as low BMD.

Results

Serum A20 level was lower in patients with T2DM compared to controls [41.30 (29.91, 61.87) vs 76.01 (54.90, 109.64) pg/mL, P<0.001]. Bivariate correlation analysis revealed that A20 level was not associated with SPPB but negatively correlated with waist-to-hip ratio (WHR). Pearson correlation analysis showed A20 level was positively correlated with lumbar spine 1-4 BMD in male diabetic patients (r=0.253, P=0.032). Multivariate regression analysis showed a positive association between serum A20 level and lumbar spine 1-4 BMD (Beta=0.047; 95% CI: 0.007-0.086; P=0.024) after multivariate adjustment. Logistic regression analysis showed that lower serum A20 level predicted low BMD in male patients with T2DM (OR: 0.22; 95% CI: 0.09-0.59; P=0.002).

Conclusions

Type 2 diabetic patients exhibited lower serum A20 level compared to non-diabetic individuals. In male patients with T2DM, serum A20 level showed a significant positive correlation with lumbar spine 1-4 BMD and could serve as an independent negative predictor for low BMD.

Could physical activity promote indicators of physical and psychological health among children and adolescents? An umbrella review of meta-analyses of randomized controlled trials

BACKGROUND

We performed an umbrella review to synthesize evidence on the effects of physical activity (PA) interventions on indicators of physical and psychological health among children and adolescents, including body mass index (BMI), blood pressure (BP), depressive symptoms, and cognitive function.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched from inception through 31 July 2023. We included meta-analyses of randomized controlled trials exploring the effects of PA interventions on BMI, BP, depressive symptoms, or cognitive function in healthy or general children and adolescents. Standard Mean Difference (SMD) was calculated for continuous outcome indicators, while Relative Risk (RR) was calculated for categorical outcome indicators.

RESULTS

A total of 21 meta-analyses were included. The evidence for the effects of PA interventions on reducing BMI [n = 68,368, SMD = - 0.04, 95% confidence interval (CI) = - 0.07 to - 0.01, P = 0.012, I2 = 46.6%], relieving diastolic BP (n = 8204, SMD = - 1.16, 95% CI = - 2.12 to - 0.20, P = 0.018, I2 = 83.1%), preventing depressive symptoms (n = 5146, SMD = - 0.21, 95% CI = - 0.31 to - 0.12, P < 0.001, I2 = 29.0%), and promoting cognitive function (n = 19,955, SMD = 0.40, 95% CI = 0.27-0.54, P < 0.001, I2 = 88.0%) was all weak but significant (class IV evidence). Subgroup analyses demonstrated that school-based and after-school PA interventions, curricular PA interventions, and PA interventions emphasizing enjoyment were more effective in reducing BMI, while curricular PA and sports programs achieved greater executive function.

CONCLUSION

PA interventions could weakly reduce BMI, relieve BP, prevent depressive symptoms, and promote cognitive function in general children and adolescents. Targeted interventions on PA should be a priority to promote physical and psychological health for children and adolescents, especially the curricular PA emphasizing enjoyment in the school settings.

Bone mineral density and the risk of kidney disease in patients with type 1 diabetes

AIM

To explore the association between bone disorder and the risk for progression of diabetic kidney disease (DKD) in persons with type 1 diabetes mellitus (T1DM).

METHODS

In this prospective cohort study the association between bone mineral density (BMD), bone-derived factors (sclerostin, Dickkopf-1, and osteoprotegerin (OPG)), and four outcomes were investigated: 1) progression of albuminuria; 2) decline in estimated glomerular filtration rate (eGFR) ≥30 %; 3) kidney failure (KF); and 4) a composite kidney outcome consisting of at least one of the outcomes.

RESULTS

In 318 participants (median follow-up time 5.5 years) patients with osteoporosis (BMD with T-score < -2.5) had increased risk of eGFR decline: hazard ratio (HR) 2.56 (95 % CI 1.06-6.19, p = 0.04), KF: HR 9.92 (95 % CI 1.16-84.95, p = 0.04), and the composite kidney outcome: HR 2.42 (95 % CI 1.18-4.96, p = 0.02). Patients with high OPG had increased risk of eGFR decline, KF, and the composite outcome, compared to patients with low OPG in unadjusted analysis. No bone-derived factor was associated with any outcome in adjusted analyses.

CONCLUSIONS

In patients with T1DM low BMD was associated with progression of DKD, suggesting an interaction between bone and kidney.

Adiponectin regulates proliferation and differentiation of chicken skeletal muscle satellite cells via ERK1/2 and p38 signaling pathways

Skeletal muscle satellite cells (SMSCs) are critical for postnatal skeletal muscle growth and regeneration. Adiponectin plays a pivotal role in regulating muscle glucose uptake and fatty acid metabolism. However, its function in the proliferation and differentiation of chicken SMSCs remains poorly understood. In this study, we investigated the effects of adiponectin on the proliferation and differentiation of in vitro cultured chicken SMSCs. Our results demonstrated that adiponectin promoted SMSCs proliferation while inhibiting myogenic differentiation and inducing adipogenic differentiation. RNA-seq analysis revealed enrichment of the MAPK signaling pathway, suggesting its potential involvement in the regulation of adiponectin on SMSCs activity. Western blot analysis revealed that adiponectin activated ERK1/2 phosphorylation and inhibited p38 phosphorylation during the process of the inhibition on myogenic differentiation in chicken SMSCs. Furthermore, suppression of ERK1/2 signaling with U0126 or activation of p38 signaling with SSK1 reversed the downregulated expression of myogenic differentiation marker MyHC, MyOD1, and MyOG induced by adiponectin. These findings validated that adiponectin impeded myogenic differentiation through activation of ERK1/2 and inhibition of p38 signaling pathways. Additionally, activation of p38 signaling pathway reduced the increased percentage of EdU-positive cells induced by adiponectin. Collectively, these findings demonstrated that adiponectin impedes myogenic differentiation of SMSCs through activating ERK1/2 and inhibiting p38 signaling pathways, while promoting proliferation by inhibiting p38 signaling pathway.

Optimised Skeletal Muscle Mass as a Key Strategy for Obesity Management

The 'Body Mass Index' (BMI) is an anachronistic and outdated ratio that is used as an internationally accepted diagnostic criterion for obesity, and to prioritise, stratify, and outcome-assess its management options. On an individual level, the BMI has the potential to mislead, including inaccuracies in cardiovascular risk assessment. Furthermore, the BMI places excessive emphasis on a reduction in overall body weight (rather than optimised body composition) and contributes towards a misunderstanding of the quiddity of obesity and a dispassionate societal perspective and response to the global obesity problem. The overall objective of this review is to provide an overview of obesity that transitions away from the BMI and towards a novel vista: viewing obesity from the perspective of the skeletal muscle (SM). We resurrect the SM as a tissue hidden in plain sight and provide an overview of the key role that the SM plays in influencing metabolic health and efficiency. We discuss the complex interlinks between the SM and the adipose tissue (AT) through key myokines and adipokines, and argue that rather than two separate tissues, the SM and AT should be considered as a single entity: the 'Adipo-Muscle Axis'. We discuss the vicious circle of sarcopenic obesity, in which aging- and obesity-related decline in SM mass contributes to a worsened metabolic status and insulin resistance, which in turn further compounds SM mass and function. We provide an overview of the approaches that can mitigate against the decline in SM mass in the context of negative energy balance, including the optimisation of dietary protein intake and resistance physical exercises, and of novel molecules in development that target the SM, which will play an important role in the future management of obesity. Finally, we argue that the Adipo-Muscle Ratio (AMR) would provide a more clinically meaningful descriptor and definition of obesity than the BMI and would help to shift our focus regarding its effective management away from merely inducing weight loss and towards optimising the AMR with proper attention to the maintenance and augmentation of SM mass and function.

Relationship between diffuse idiopathic skeletal hyperostosis and lumbar paravertebral muscle fat infiltration: a CT-based retrospective study

PURPOSE

Plentiful evidence points to a significant correlation between paravertebral muscles and spinal diseases. Yet, no reports are available detailing the association between paravertebral muscle status and diffuse idiopathic skeletal hyperostosis (DISH). The purpose of this retrospective study was to assess the link between paravertebral muscle area as well as fat infiltration and DISH based on computer tomography.

METHODS

Data were obtained from patients with acute vertebral fractures who presented to a single spine center. All participants had whole spine lateral x-ray radiography for DISH diagnosis. Those with a history of spinal disease, fusion surgery, or tumors were excluded. Patients with or without DISH were propensity-matched by age, sex, and body mass index (BMI). Appropriate Mann-Whitney U-tests or independent t-tests were performed to evaluate the correlation between muscle area or fat infiltration of the L3 level paravertebral muscles and DISH.

RESULTS

A total of 114 DISH and 114 non-DISH patients were assessed. The fat infiltration in the paravertebral muscles was remarkably higher in the DISH group than in the non-DISH (p < 0.05), whereas there was no statistical difference in the muscle area of the two (p > 0.05).

CONCLUSION

In conclusion, the fat infiltration of the paravertebral muscles was significantly associated with DISH.

Effect of life course body composition on lipids and coronary atherosclerosis mediated by inflammatory biomarkers

OBJECTIVE

To investigate the mediating role of inflammatory biomarkers in the causal effect of body composition on lipids and atherosclerosis.

METHODS

Retrospective observational study and Mendelian randomization (MR) study were used. Observational analyses were undertaken using data from 4717 children and adolescents aged 6-18 years from Chinese who underwent dual-energy x-ray absorptiometry for body composition. MR analyses were based on summary statistics from UK Biobank, deCODE2021, GLGC, FinnGen and other large consortiums. Inflammatory biomarkers included leptin, insulin, adiponectin, osteocalcin, fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH).

RESULTS

In retrospective observational study, through osteocalcin, body composition had effects on total cholesterol (TC), triglyceride and low-density lipoprotein cholesterol (LDL). Conversely, fat mass vs. fat-free mass demonstrated opposing effects. Insulin played a role in the association of fat mass with TC and LDL (all P < 0.05). Mediation MR results indicated the causal effect of fat-free mass on coronary atherosclerosis via insulin (indirect effect, OR (odds ratio): 0.95 [95%CI, 0.92-0.98]) and adiponectin (OR: 0.96 [95%CI, 0.93-0.99]). Adiponectin also mediated the causal association of fat mass with coronary heart disease (OR: 1.06 [95%CI, 1.02-1.10]) and coronary atherosclerosis (OR: 1.05 [95%CI, 1.01, 1.09]). Leptin, adiponectin and insulin played roles in mediating the casual effects of body composition on triglyceride and high-density lipoprotein cholesterol.

CONCLUSIONS

Our findings suggest different body composition exert varying influences on lipids and atherosclerosis through distinct inflammatory biomarkers. The findings may be helpful in tailoring management of body composition based on inflammatory biomarkers with different lipid profiles.

The Role of Myokines in Liver Diseases

Myokine is a general term for hormones, peptides, and other substances secreted by skeletal muscle. Myokine has attracted much attention in recent years as a key substance for understanding the mechanism of "exercise and health". Skeletal muscle accounts for about 40% of the total human weight and is now recognized as an endocrine organ that produces myokines, which have physiological activity. Representative myokines include IL-6, myostatin, irisin, brain-derived neurotropic factor, fibroblast growth factor-21, and decorin. On the other hand, sarcopenia, defined by quantitative and qualitative loss of skeletal muscle, is a condition that has received much attention in recent years because of its close correlation with prognosis. In patients with chronic liver disease (CLD), sarcopenia is a common complication. Mechanisms underlying sarcopenia in CLD patients have been reported to involve protein-energy malnutrition, which is characteristic of patients with cirrhosis, signaling involved in protein synthesis and degradation, myokines such as myostatin and decorin, the ubiquitin-proteasome pathway, sex hormones such as testosterone, dysbiosis, and insulin resistance, etc., in addition to aging. Each of these pathological conditions is thought to be intricately related to each other, leading to sarcopenia. This review will summarize the relationship between CLD and myokines.

Metabolism-Related Adipokines and Metabolic Diseases: Their Role in Osteoarthritis

Osteoarthritis (OA) affects several joints but tends to be more prevalent in those that are weight-bearing, such as the knees, which are the most heavily loaded joints in the body. The incidence and disability rates of OA have continued to increase and seriously jeopardise the quality of life of middle-aged and older adults. However, OA is more than just a wear and tear disease; its aetiology is complex, and its pathogenesis is poorly understood. Metabolic syndrome (MetS) has emerged as a critical driver of OA development. This condition contributes to the formation of a distinct phenotype, termed metabolic syndrome-associated osteoarthritis (MetS-OA),which differs from other metabolically related diseases by its unique pathophysiological mechanisms and clinical presentation. As key mediators of MetS, metabolic adipokines such as leptin, lipocalin, and resistin regulate inflammation and bone metabolism through distinct or synergistic signaling pathways. Their modulation of inflammatory responses and bone remodeling processes plays a critical role in the pathogenesis and progression of OA. Due to their central role in regulating inflammation and bone remodeling, metabolic adipokines not only deepen our understanding of MetS-OA pathogenesis but also represent promising targets for novel therapeutic strategies that could slow disease progression and improve clinical outcomes in affected patients.

Circulating biomarkers associated with walking performance in elderly subjects: exploring miRNAs, metabolic and inflammatory biomarkers

Aging phenotype is characterized by musculoskeletal impairment that leads to diminished mobility and physical function. This study investigated whether circulating miRNAs and metabolic and inflammatory biomarkers may reflect the walking performance of the elderly. Elderly hospitalized for an acute condition and recruited from the ReportAge Biobank were grouped, based on their walking performance, in active subjects (n = 23, age: 83.0 ± 4.3), able to walk ≥ 1 km and who performed more than 1 h activity, and inactive subjects (n = 23, age: 85.0 ± 6.0), able to walk < 100 m and who performed < 1 h activity in the 3 days prior hospitalization. Plasma levels of 754 miRNAs were evaluated using OpenArray® platform, and miRNAs whose level was ± 2.5 fold (p < 0.05) were validated by qPCR. Target prediction for validated miRNAs was performed on MirWalk 3.0, Gene Ontology and pathway enrichment on Panther 19.0. Cytokines and metabolites associated with bone, muscle, and inflammation were evaluated from plasma samples using Luminex and ELISA. Among the 7 miRNAs found differentially expressed in active compared to inactive elderly after the initial screening, 4 miRNAs were validated: hsa-let7g-5p, hsa-miR-27a-3p, hsa-miR-361-5p, hsa-miR-574-3p, all upregulated in the active group. Gene Ontology and pathway enrichment analysis revealed the identified miRNAs potentially involved in muscle and bone metabolism during aging. Among cytokines, gp130 and IL-10 significantly differed between the two groups. This study suggests the potential association of specific circulating biomarkers with walking performance in elderly and their potential involvement in the molecular mechanism underlying age-associated musculoskeletal impairment.

Undernutrition risk and obesity increase the risk of osteosarcopenia in Mexican adults aged 50 and over: a prospective cohort study

Introduction

Undernutrition risk in adults is a common but undiagnosed condition, while obesity is highly prevalent in this population. Osteosarcopenia is the coexistence of sarcopenia and osteopenia/osteoporosis and is related to higher morbidity and mortality. Undernutrition has been identified as an associated factor of osteosarcopenia; however, it is unknown whether undernutrition risk is also related to this condition. On the other hand, obesity has been associated with osteosarcopenia, and several biological mechanisms in the relationship between muscle, bone, and fat have been identified. However, in both cases, there is a lack of longitudinal studies that allow evaluation of whether these conditions precede and increase the risk of osteosarcopenia. Therefore, the objective was to evaluate the association between undernutrition risk and obesity with osteosarcopenia among Mexican community-dwelling adults aged 50 and over.

Methods

This is a secondary longitudinal study from the FraDySMex cohort. We considered data from 2014 and 2015 as baseline evaluations and 2019 as the follow-up evaluation. Undernutrition risk was assessed using the Mini Nutritional Assessment, obesity was assessed based on body fat percentage measured by DXA, and osteosarcopenia was diagnosed according to the FNIH criteria. To evaluate the association of obesity and undernutrition risk, we estimated mixed-effects logistic regression models. The final model was adjusted for sex, age, comorbidity, education, physical activity, and cognitive impairment.

Results

A total of 304 participants with two evaluations (baseline and follow-up) were included in the study. The baseline mean age of participants was 69.6 years (SD 9.1), with ages ranging from 50 to 92 years. Most of the participants were female (83.2%), 40% had between 7 and 12 years of education, and almost half were categorized as sedentary (47.8%) at baseline evaluation. Both undernutrition risk and obesity increased the risk of osteosarcopenia, with an OR of 2.24 (95% CI: 1.20-4.19) and an OR of 2.22 (95% CI: 1.17-4.23), respectively.

Conclusion

Our findings suggest that undernutrition risk, on the one hand, and obesity, on the other hand, can precede and increase the risk of osteosarcopenia in community-dwelling adults aged 50 and over.

Stable Gastric Pentadecapeptide BPC 157 as Therapy After Surgical Detachment of the Quadriceps Muscle from Its Attachments for Muscle-to-Bone Reattachment in Rats

BACKGROUND

This is a novel rat study using native peptide therapy, focused on reversing quadriceps muscle-to-bone detachment to reattachment and stable gastric pentadecapeptide BPC 157 per-oral therapy for shared muscle healing and function restoration.

METHODS

Pharmacotherapy recovering various muscle, tendon, ligament, and bone lesions, and severed junctions (i.e., myotendinous junction), per-oral in particular (BPC 157/kg/day 10 µg, 10 ng), provides muscle-to-bone reattachment after quadriceps muscle detachment, both complete (rectus muscle) and partial (vastus muscles).

RESULTS

Immediately post-injury, and at 1, 2, 3, 5, 7, 14, 21, 28, 60, and 90 days post-injury, quadriceps muscle-to-bone detachment showed definitive healing failure (impaired walking and permanent knee flexure). Contrarily, macro/microscopic, ultrasonic, magnetic resonance, biomechanical, and functional assessments revealed that BPC 157 therapy recovering effects for all time points were consistent. All parameters of the walking pattern fully improved, and soon after detachment and therapy application, muscle approached the bone, leaving a minimal gap (on ultrasonic assessment), and leg contracture was annihilated. The healing process occurs immediately after detachment from both sides: the muscle and the bone. The reattachment fibers from the ends of the muscle could be traced into the new bone formed at the surface (note, at day 3 post-detachment, increased mesenchymal cells occurred with periosteum reactivation). Consequently, at 3 months, the form was stable, and the balance between the muscle and bone was the following: well-organized bone, newly formed as more cortical bone providing a narrower bone marrow space, and the muscle and mature fibers were oriented parallel to the bone axis and were in close contact with bone.

CONCLUSIONS

Therefore, to achieve quadriceps muscle-to-bone reattachment, the BPC 157 therapy reversing course acts from the beginning, resolving an otherwise insurmountable deleterious course.

Exerkines and Sarcopenia: Unveiling the Mechanism Behind Exercise-Induced Mitochondrial Homeostasis

Background/Objectives: Sarcopenia, characterized by the progressive loss of muscle mass and strength, is linked to physical disability, metabolic dysfunction, and an increased risk of mortality. Exercise therapy is currently acknowledged as a viable approach for addressing sarcopenia. Nevertheless, the molecular mechanisms behind exercise training or physical activity remain poorly understood. The disruption of mitochondrial homeostasis is implicated in the pathogenesis of sarcopenia. Exercise training effectively delays the onset of sarcopenia by significantly maintaining mitochondrial homeostasis, including promoting mitophagy, improving mitochondrial biogenesis, balancing mitochondrial dynamics, and maintaining mitochondrial redox. Exerkines (e.g., adipokines, myokines, hepatokines, and osteokines), signaling molecules released in response to exercise training, may potentially contribute to skeletal muscle metabolism through ameliorating mitochondrial homeostasis, reducing inflammation, and regulating protein synthesis as a defense against sarcopenia. Methods: In this review, we provide a detailed summary of exercise-induced exerkines and confer their benefit, with particular focus on their impact on mitochondrial homeostasis in the context of sarcopenia. Results: Exercise induces substantial adaptations in skeletal muscle, including increased muscle mass, improved muscle regeneration and hypertrophy, elevated hormone release, and enhanced mitochondrial function. An expanding body of research highlights that exerkines have the potential to regulate processes such as mitophagy, mitochondrial biogenesis, dynamics, autophagy, and redox balance. These mechanisms contribute to the maintenance of mitochondrial homeostasis, thereby supporting skeletal muscle metabolism and mitochondrial health. Conclusions: Through a comprehensive investigation of the molecular mechanisms within mitochondria, the context reveals new insights into the potential of exerkines as key exercise-protective sensors for combating sarcopenia.

Associations Between Adherence to the Mediterranean Diet and Incident Sarcopenia in Prospective Cohort Studies

The loss of skeletal muscle mass and strength, known as sarcopenia, is prevalent in older adults and linked to an increased risk of disability, frailty, and early mortality. Muscle health is crucial for the functionality and independence of older adults. As the aging population continuously grows, finding cost-effective strategies for preventing and treating sarcopenia is an important public health priority. While nutrition is recognized as a key factor in the development of sarcopenia, its role in preventing and treating the condition is still under investigation. In recent decades, nutritional research has shifted from a focus on individual nutrients or healthy foods to examining the combination of nutrients and foods in dietary patterns, along with their potential synergistic and antagonistic effects. A balanced diet and regular participation in physical activity are essential for maintaining musculoskeletal health. One of the healthy eating patterns with the greatest evidence of multiple health benefits is the Mediterranean diet, which has also been linked to positive effects on muscle function in observational studies. However, there is a lack of intervention studies. This review explores the updated evidence from longitudinal prospective studies on associations between adherence to the Mediterranean diet and sarcopenia in order to promote preventive and intervention strategies for healthy muscle aging.

Changes to muscle and fascia tissue after eighteen days of ankle immobilization post-ankle sprain injury: an MRI case study

BACKGROUND

Ankle sprains often result in muscle atrophy and reduced range of motion, which can cause long-term ankle instabilities. Understanding the changes to muscle-such as atrophy-and concomitant changes to deep fascia-which may thicken alongside muscle loss-after ankle sprain injury is important to understanding structural changes about the joint and how they might contribute to longer-term impairments. Here, we employ advanced MRI to investigate skeletal muscle and fascial structural changes during the recovery period of one patient undergoing immobilization after ankle sprains.

MATERIAL AND METHODS

In this case study, a participant who suffered an ankle sprain underwent initial MRI scans and, after 21 days (18 of which included immobilization), a follow-up MRI. Techniques used included proton density, 3D stack of spirals, and diffusion tensor imaging to analyse muscle and fascia changes pre- and post-injury.

RESULTS

Results showed muscle atrophy in most shank muscles, with volume loss ranging from no change in the lateral gastrocnemius to 12.11% in the popliteus. Thigh muscles displayed hypertrophy of 6% in the hamstrings, while the quadriceps atrophied by 2.5%. Additionally, fascia thickness increased from 0.94 mm to 1.03 mm. Diffusion tensor imaging indicated that the biceps femoris experienced the most significant changes in physiological cross-sectional area, while the rectus femoris showed minimal change.

CONCLUSION

The findings highlight the variable responses of muscles and a notable thickening of deep fascia post-injury, underscoring its role in recovery from ankle sprains.

Prevalence of lumbar disc herniation and its associated factors: A cross-sectional study in Gansu

BACKGROUND AND OBJECTIVE

The prevalence rate of LDH and its influencing factors in Gansu is unclear. This study aims to analyze the prevalence of LDH and influencing factors in Gansu.

METHODS

A stratified multi-stage random sampling method was used to obtain representative samples of residents more than 18 years old from <1500m, 1500-3500m, and >3500m altitude sites in Gansu, China, in June 2022 to August 2022. A unified questionnaire was used for the investigation.

RESULTS

The total number of people surveyed was 4545, with a prevalence rate of 22.77% for LDH. LDH prevalence differed by latitude, city, age, sex, nationality, education, marital status, income, drinking habits, residence duration, physical activity, exercise intensity, health status (including hypertension, diabetes, CHD, chronic infection, and tumors) (all P <0.05). Logistic regression showed higher LDH risk at high (OR = 2.250) and middle latitudes (OR = 2.551), among males (OR = 0.808), ages 35-49 (OR = 1.530) and 50-64 (OR = 1.991), Tibetans (OR = 1.533) and Hui (OR = 0.557), alcohol consumers (OR = 0.696), those with moderate (OR = 0.742) and mild physical activity (OR = 0.840), cadres (OR = 0.46), workers (OR = 1.568), farmers/herdsmen (OR = 1.840), married individuals (OR = 2.239), residents for ≥36 months (OR = 0.618), annual income ≥50,000 yuan (OR = 1.246), central obesity (OR = 1.399), and those with tumors (OR = 3.953), hypertension (unknown, OR = 1.817), diabetes (yes, OR = 0.529, unknown, OR = 0.565), CHD (unknown, OR = 1.404), and osteoporosis (unknown, OR = 1.404).

CONCLUSION

The prevalence of LDH was high, varying significantly with latitude, gender, and nationality, indicating potential lifestyle and demographic influences in Gansu.

Modeling Musculoskeletal Disorders in Zebrafish: Advancements in Muscle and Bone Research

Zebrafish (Danio rerio) have emerged as a valuable model organism for investigating musculoskeletal development and the pathophysiology of associated diseases. Key genes and biological processes in zebrafish that closely mirror those in humans, rapid development, and transparent embryos make zebrafish ideal for the in vivo studies of bone and muscle formation, as well as the molecular mechanisms underlying musculoskeletal disorders. This review focuses on the utility of zebrafish in modeling various musculoskeletal conditions, with an emphasis on bone diseases such as osteoporosis and osteogenesis imperfecta, as well as muscle disorders like Duchenne muscular dystrophy. These models have provided significant insights into the molecular pathways involved in these diseases, helping to identify the key genetic and biochemical factors that contribute to their progression. These findings have also advanced our understanding of disease mechanisms and facilitated the development of potential therapeutic strategies for musculoskeletal disorders.

Association between C-reactive protein and sarcopenia: The National Health and Nutrition Examination Survey

C-reactive protein (CRP), a clinical biomarker, is frequently used to evaluate the inflammatory status of the body. However, the association between CRP levels and sarcopenia among the general adult population in the USA is unknown. This study focused on assessing whether CRP levels were associated with sarcopenia. This cross-sectional study collected adult data of adults from the 2015 to 2018 National Health and Nutrition Examination Survey. Four-extremity total muscle mass was used to evaluate sarcopenia (appendicular lean mass). In addition, dual-energy X-ray absorptiometry was adopted to measure appendicular lean mass. The CRP levels were used to assess inflammation status. Odds ratios (OR) and 95% confidence intervals (95% CI) were determined using multivariable logistic regression to analyze the association between CRP levels and sarcopenia. A multivariable-adjusted restricted cubic spline model was built to plot OR curves at 4 knots. Among the 3710 participants involved in this study (average age, 39.4 [11.54] years; 1801 [48.5%] men), 352 (9.5%) displayed characteristics of sarcopenia, while 3358 (90.5%) did not. Compared with participates in the lowest quartile (Q1) of CRP level (Q1; ≤0.08 to ≤0.7), those in the highest quartile (Q4; ≤4.3 to ≤188.5) had an adjusted OR for sarcopenia of 2.74 (95% CI, 1.65-4.57; P < .001). Based on the multivariable restricted cubic spline model, CRP levels showed a nonlinear association with sarcopenia (P < .001). The adjusted OR of sarcopenia of 1.86 (95% CI, 1.37-2.51; P < .001) was determined by 2 piecewise regression models for those having the CRP level of 1.8. Based on subgroup analysis, CRP levels were related to sarcopenia in males (OR, 1.03; 95% CI, 1-1.05) and individuals aged <50 years (OR, 1.03; 95% CI, 1.01-1.05), drinking (OR, 1.02; 95% CI, 1-1.03), and body mass index ≥ 25 kg/m2 (OR, 1.02; 95% CI, 1-1.03). Our results indicated that CRP levels showed a nonlinear correlation with sarcopenia among adults in the US.

Diagnostic Power of Serum Creatinine/Cystatin C Ratio for Identifying Low MRI-Muscle Volume and Low Grip Strength: Data From 9 731 to 149 707 UK Biobank Older Adults

BACKGROUND

Biomarkers for sarcopenia are lacking. We examined the diagnostic power of serum creatinine to cystatin C ratio for identifying low magnetic resonance imaging-muscle volume and low grip strength in a large observational study of UK Biobank older adults.

METHODS

Serum creatinine and cystatin C were measured via immunoassays (Beckman Coulter AU5800 and Siemens Advia 1800, respectively) and grip strength by hydraulic hand dynamometer at baseline visit (2008-2010). magnetic resonance imaging-thigh fat-free muscle volume and DXA-derived appendicular lean mass were measured at imaging visit (2014-2018). Extreme outliers were removed, and covariates (demographic, lifestyle, and clinical factors, as well as time elapsed between baseline-imaging visit) were adjusted for in statistical models.

RESULTS

12 873 older adults (mean age: 63.5 ± 2.7 years, 44.2% women) were included for fat-free muscle volume and appendicular lean mass/body mass index; 149 707 older adults (mean age: 64.0 ± 2.9 years, 50.5% women) for grip strength. Despite significant associations (p < .05), in fully adjusted models, creatinine to cystatin C showed poor to acceptable diagnostic power for identifying low fat-free muscle volume when using cutpoints of 20th percentile (area under the curve: 0.577 men; 0.622 women) and T scores of -2 (area under the curve: 0.596 men; 0.659 women) and -2.5 (area under the curve: 0.609 men; 0.722 women). In fully adjusted model, creatinine to cystatin C showed poor diagnostic power (area under the curves: <0.70) for identifying low appendicular lean mass/body mass index or low grip strength, irrespective of the cutpoint used.

CONCLUSIONS

Creatinine to cystatin C may not be a suitable biomarker for identifying low muscle volume or low strength in older adults. This finding, drawn from a large sample size and the use of advanced medical imaging, marks an important contribution to the sarcopenia field.

Current Challenges, Solutions, and Novel Directions in Research and Clinical Care: Proceedings From the 14th Annual International Workshop on HIV and Aging

Integrating antiretroviral therapy into HIV care dramatically extended the lifespan for people living with HIV. Improving the health span requires understanding aging, HIV, associated comorbid conditions, and concurrent treatments. The 14th annual International Workshop on HIV and Aging on October 26-27, 2023 included podium presentations on: Sarcopenia: Biology, Pathophysiology, Prevention and Treatment; Long-acting ART; Central Nervous System (CNS) complications; Asymptomatic Neurocognitive Impairment (ANI); Mental Health; Loneliness; and Resilience. Presentations highlighted persistent concerns for people living with HIV including sarcopenia and frailty, mental health, loneliness, and cognition. Presenters encouraged prioritizing mental health treatment, reducing social isolation, and research on resiliency.

Training with reduced carbohydrate availability affects markers of bone resorption and formation in male academy soccer players from the English Premier League

PURPOSE

To test the hypothesis that training with reduced carbohydrate (CHO) availability increases bone resorption in adolescent soccer players.

METHODS

In a randomised crossover design, ten male players (age: 17.4 ± 0.8 years) from an English Premier League academy completed an acute 90-min field-based training session (occurring between 10:30-12:00) in conditions of high (TRAIN HIGH; 1.5 g.kg-1, 60 g, 1.5 g.kg-1 and 1.5 g.kg-1 consumed at 08:00, during training, 12:30 and 13:30, respectively) or low CHO availability (TRAIN LOW; 0 g.kg-1). Participants also completed a non-exercise trial (REST) under identical dietary conditions to TRAIN LOW. Venous blood samples were obtained at 08:30, 10:30, 12:30 and 14:30 for assessment of bone resorption (βCTX), bone formation (PINP) and calcium metabolism (PTH and ACa).

RESULTS

External training load did not differ (all P > 0.05) between TRAIN HIGH and TRAIN LOW, as evident for total distance (5.6 ± 0.8; 5.5 ± 0.1 km), average speed (81 ± 9; 85 ± 12 m.min-1) and high-speed running (350 ± 239; 270 ± 89 m). Area under the curve for both βCTX and PINP was significantly greater (P < 0.01 and P = 0.03) in TRAIN LOW versus TRAIN HIGH, whilst no differences in PTH or ACa (P = 0.11 and P = 0.89) were observed between all three trials.

CONCLUSION

CHO restriction before, during and after an acute soccer training session increased bone (re)modelling markers in academy players. Despite acute anabolic effects of bone formation, the long-term consequence of bone resorption may impair skeletal development and increase injury risk during growth and maturation.

Deciphering the mechanisms and effects of hyperglycemia on skeletal muscle atrophy

Hyperglycemia, a hallmark of diabetes mellitus, significantly contributes to skeletal muscle atrophy, characterized by progressive muscle mass and strength loss. This review summarizes the mechanisms of hyperglycemia-induced muscle atrophy, examines clinical evidence, and discusses preventive and therapeutic strategies. A systematic search of electronic databases, including PubMed, Scopus, and Web of Science, was conducted to identify relevant papers on hyperglycemic skeletal muscle atrophy. Key mechanisms include insulin resistance, chronic inflammation, oxidative stress, and mitochondrial dysfunction. Crucial molecular pathways involved are Phosphoinositide 3-kinase/Protein kinase B signaling, Forkhead box O transcription factors, the ubiquitin-proteasome system, and myostatin-mediated degradation. Hyperglycemia disrupts normal glucose and lipid metabolism, exacerbating muscle protein degradation and impairing synthesis. Clinical studies support the association between hyperglycemia and muscle atrophy, emphasizing the need for early diagnosis and intervention. Biomarkers, imaging techniques, and functional tests are vital for detecting and monitoring muscle atrophy in hyperglycemic patients. Management strategies focus on glycemic control, pharmacological interventions targeting specific molecular pathways, nutritional support, and tailored exercise regimens. Despite these advances, research gaps remain in understanding the long-term impact of hyperglycemia on muscle health and identifying novel therapeutic targets. The review aims to provide a comprehensive understanding of the mechanisms, clinical implications, and potential therapeutic strategies for addressing hyperglycemia-induced skeletal muscle atrophy.

Irisin in degenerative musculoskeletal diseases: Functions in system and potential in therapy

Degenerative musculoskeletal diseases are a class of diseases related to the gradual structural and functional deterioration of muscles, joints, and bones, including osteoarthritis (OA), osteoporosis (OP), sarcopenia (SP), and intervertebral disc degeneration (IDD). As the proportion of aging people around the world increases, degenerative musculoskeletal diseases not only have a multifaceted impact on patients, but also impose a huge burden on the medical industry in various countries. Therefore, it is crucial to find key regulatory factors and potential therapeutic targets. Recent studies have shown that irisin plays an important role in degenerative musculoskeletal diseases, suggesting that it may become a key molecule in the prevention and treatment of degenerative diseases of the musculoskeletal system. Therefore, this review provides a comprehensive description of the release and basic functions of irisin, and summarizes the role of irisin in OA, OP, SP, and IDD from a cellular and tissue perspective, providing comprehensive basis for clinical application. In addition, we summarized the many roles of irisin as a key information molecule in bone-muscle-adipose crosstalk and a regulatory molecule involved in inflammation, senescence, and cell death, and proposed the interesting possibility of irisin in degenerative musculoskeletal diseases.

Oct-B: A derivative of L-BAIBA significantly alleviating high-fat diet-induced obesity in mice

The rising prevalence of obesity is a global health concern. Supplementation with (S)-β-aminoisobutyric acid (L-BAIBA) has shown potential in preventing obesity and related metabolic disorders induced by high-fat diets. However, developing effective and low-toxicity BAIBA derivatives remains a challenging yet promising field. In this study, we introduce Oct-B, a novel BAIBA ester compound, which exhibits 80-fold greater efficacy than L-BAIBA in alleviating obesity in high-fat diet-fed mice. Our results demonstrate that Oct-B significantly reduces serum TG, TC, LDL-C, and the activities of ALT and AST, and also reduces TG and TC in liver, surpassing the effects of L-BAIBA. Histological analysis shows that Oct-B significantly decreases lipid accumulation in liver tissues, normalizes mast cells in white adipose tissue, and upregulates the expression of UCP1 protein in white adipose tissue. The qRT-PCR results indicated Oct-B alleviates obesity by downregulating lipogenic genes (PPARγ, ACC1, FAS), upregulating lipolysis related genes (PPARα, HSL) and thermogenic gene UCP1. Additionally, quantitative mass spectrometry reveals a marked increase in L-BAIBA levels in white fat, brown fat, serum, and muscle following Oct-B administration. These findings suggest that Oct-B is an efficient L-BAIBA substitute, offering a promising therapeutic approach for preventing and treating high-fat diet-induced obesity.

Fracture severity dependence of bone and muscle performance in patients following single or multiple vertebral fractures

BACKGROUND

Few studies focus on the clinical, laboratory, radiological, and biological characteristics of bone and muscle of multiple vertebral fractures, which are associated with a more poor prognosis compared with single fracture.

PURPOSE

To compare the BMD, bone turnover, muscularity, fatty infiltration of muscle, and prevalence of co-morbidities in patients with single and multiple vertebral fractures.

METHODS

We recruited 100 patients with single fracture (age 66.96 ± 8.24 years) and 100 with multiple fractures (age 69.90 ± 7.80 years); performed dual-energy X-ray absorptiometry of the femoral neck, hip, and lumbar vertebrae; and measured biochemical markers of bone turnover, muscularity, and fatty infiltration.

RESULTS

Patients with multiple vertebral fractures had lower hip BMD (p=0.010) than those with single fractures, but there was no difference in femoral neck and lumbar vertebral BMD nor in muscularity. However, fatty infiltration, an indicator of muscle quality, was significantly higher in participants with multiple fractures (p=0.006). Diabetes was significantly more common in patients with multiple fractures (p=0.042). There were no significant differences in markers of bone turnover, and Seperman analyses showed no correlations of CTX-1 or tPINP with the BMD of the hip, femoral neck, or lumbar spine. However, high CTX-1 was associated with high tPINP (r=0.4805; p<0.0001), and marked fatty infiltration was associated with low hip, lumbar vertebral, and femoral neck BMD. Cox regression analyses showed that age (OR 1.057; 95% CI 1.016-1.101; p=0.006) and low hip BMD (OR 0.016; 95% CI, 0.000-0.549; p=0.022) were associated with a higher risk of multiple fractures.

CONCLUSION

Patients with multiple fractures tend to have lower hip BMD, a history of type 2 diabetes, and more substantial fatty infiltration of muscle than in those with single fractures. Age and hip BMD rather than lumbar vertebrae BMD were found to be independent risk factors for multiple vertebral compression fractures, implying that hip BMD may be a more sensitive predictor for multiple vertebral fractures. More improvements in hip BMD and focus on older persons may be useful means of preventing multiple fractures.

Effects of Creatine Monohydrate Supplementation on Muscle, Bone and Brain- Hope or Hype for Older Adults?

PURPOSE OF REVIEW

Sarcopenia, generally characterized by the age-related reduction in muscle strength, lean/muscle mass and functional ability, is also associated with reduced bone mass and strength and impaired brain health and function. One potential intervention which has received much 'hype' over the past few decades to countermeasure these negative consequences of biological aging is creatine monohydrate supplementation.

RECENT FINDINGS

From a skeletal muscle perspective, the combination of creatine monohydrate supplementation and resistance training provides 'hope' for older adults as it improves measures of lean mass, regional (limb) muscle thickness, upper- and lower-body muscle strength and functional ability. Further, there is some evidence that creatine (supplementation or habitual diet) provides a ray of 'hope' for improving some aspects of cognitive function. The majority of research suggests that creatine is more 'hype' than 'hope' for improving measures of bone mass in older adults. Creatine monohydrate supplementation provides some anti-sarcopenic benefits for older adults.

Associations of Serum Irisin and Fibroblast Growth Factor-21 Levels With Bone Mineral Characteristics in Eumenorrheic Adolescent Athletes With Different Training Activity Patterns

PURPOSE

To describe serum irisin and fibroblast growth factor-21 (FGF-21) concentrations in healthy female adolescents with different training activity patterns and their associations with bone mineral properties and metabolic markers.

METHODS

A total of 62 adolescent girls aged 14-18 years were recruited: 22 rhythmic gymnasts, 20 swimmers, and 20 untrained controls. Bone mineral characteristics by dual-energy X-ray absorptiometry, daily energy intake by dietary recall, serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen were measured in all girls.

RESULTS

Whole body and lumbar spine areal bone mineral density and lumbar spine bone mineral content were higher in the rhythmic gymnasts group compared with swimmers and untrained controls groups (P < .05). Serum irisin, FGF-21, undercarboxylated osteocalcin, and C-terminal telopeptide of type I collagen levels were not significantly different between the groups. In the rhythmic gymnasts group, serum FGF-21 concentration was positively correlated with lumbar spine areal bone mineral density independently of confounding factors (r = .51; P = .027).

CONCLUSIONS

Serum irisin and FGF-21 levels were not different between adolescent eumenorrheic girls with different training activity patterns. FGF-21 was positively associated with lumbar spine areal bone mineral density, which predominantly consists of trabecular bone in adolescent rhythmic gymnasts.

Mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes

OBJECTIVE

The aim was to investigate the mediating role of inflammatory biomarkers in the causal effect of body composition on glycaemic traits and type 2 diabetes.

METHODS

A retrospective observational study and a Mendelian randomization (MR) study were used. Observational analyses were performed using data from 4717 Chinese children and adolescents aged 6-18 years who underwent dual-energy X-ray absorptiometry for body composition. MR analyses were based on summary statistics from UK Biobank, deCODE2021, Meta-Analysis of Glucose and Insulin-Related Traits Consortium (MAGIC) and other large consortiums. Inflammatory biomarkers included leptin, adiponectin, osteocalcin, fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH).

RESULTS

In a retrospective observational study, increased fat mass had a positive effect on homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of pancreatic beta cell function (HOMA-β) through FGF23, whereas fat-free mass produced the opposite effects. PTH and osteocalcin played significant roles in the association of fat mass and fat-free mass with fasting glucose, fasting insulin and HOMA-IR (all p < 0.05). Mediation MR results indicated that childhood body mass index affected glycaemic traits through leptin and adiponectin. There existed a causal effect of fat-free mass on type 2 diabetes via FGF23 (indirect effect: OR [odds ratio]: 1.14 [95% CI, confidence interval: 1.01-1.28]) and adiponectin (OR: 0.85 [95% CI: 0.77-0.93]). Leptin mediated the causal association of fat mass (indirect effect: β: -0.05 [95% CI: -0.07, -0.02]) and fat-free mass (β: 0.03 [95% CI: 0.01, 0.04]) with fasting glucose.

CONCLUSIONS

Our findings suggest that different body compositions have differential influences on glycaemic traits and type 2 diabetes through distinct inflammatory biomarkers. The findings may be helpful in tailoring management of body composition based on inflammatory biomarkers with different glycaemic statuses.

Exercise-induced interactions between skeletal muscle and bone via myokines and osteokine in mice: Role of FNDC5/irisin, IGF-1, and osteocalcin

Skeletal muscle and bone interact to maintain their structure and function. Physical exercise is the most effective and easily applicable strategy to maintain their functions; however, exercise-induced interactions by soluble factors remained elusive. Our study aimed to identify exercise-induced interactions between muscle and bone by examining (1) the effects of myokine on bone and (2) the effects of osteocalcin (OCN) on skeletal muscle. To understand the effects of exercise-induced myokines on bone, we examined the effects of FNDC5 for aerobic exercise and IGF-1 for resistance exercise using a muscle-specific myokine overexpression model. To examine OCN effects on muscle, mice were intraperitoneally administered OCN-neutralizing antibody during long-term exercise. Our result showed that aerobic exercise tended to increase serum HA-tag protein attached to FNDC5 in muscle-specific overexpression groups. In addition, osteoblastic activation was increased only after aerobic exercise with HA/FNDC5 overexpression. Resistance exercise did not alter circulating HA-tag (muscle-derived IGF-1) and bone metabolism after IGF-1/HA overexpression. In the OCN study, aerobic exercise enhanced endurance capacity by restoring muscle glycogen content; however, OCN neutralization returned these to baseline. After resistance exercise, OCN suppression inhibited muscle hypertrophy and strength gains by preventing protein synthesis. Our results suggest that aerobic exercise following FNDC5 muscle overexpression promotes osteoblast activity, which may be partially caused by muscle-derived FNDC5 secretion. In addition, OCN was necessary for muscle adaptation in both aerobic and resistance exercises.

Analysis of body composition, functionality and muscle-specific strength of older women with obesity, sarcopenia and sarcopenic obesity: a cross-sectional study

During aging, changes in body composition can result in sarcopenic obesity, which is a condition in which obesity occurs accompanied by the loss of muscle mass and strength caused by sarcopenia. Although the effects of obesity and sarcopenia on body composition are known, the muscle-specific strength in older women with sarcopenic obesity remains under-researched. The objective of this study was to evaluate community-dwelling older women for the absence or presence of obesity, sarcopenia and sarcopenic obesity and compare them in terms of body composition, functional physical performance and muscle-specific strength. One hundred and fifty-six older women (± 74 years) were evaluated for body composition using Dual X-ray Absorptiometry, handgrip strength with a Jamar dynamometer and functional performance using gait speed and timed up and go tests. The presence of obesity, sarcopenia and sarcopenic obesity was found in 32.7%, 15.4% and 25% of the sample, respectively. Comparing groups, community-dwelling older women with sarcopenic obesity exhibited poorer functional physical performance (TUG ± 14 s), and lower muscle-specific strength (± 1.18). Sarcopenic obesity was associated with muscle-specific strength (95% IC 0.016-0.241), and TUG (95% CI 1.001-1.137). These findings indicate that the combination of obesity and sarcopenia has a negative impact on skeletal muscle, reducing muscle-specific strength and physical performance in older women with more declines than either disease alone. Therefore, this comprehensive assessment gives useful information for incorporating muscle-specific strength into the diagnosis of sarcopenic obesity in the older people.

Correlation analysis of exercise volume and musculoskeletal disorders in people with income level differences: research based on the 2011-2018 NHANES dataset

OBJECTIVES

Socioeconomic factors significantly impact human health; however, the impact of exercise and income on musculoskeletal system health remains unclear. Our study aims to explore the relationship between exercise and income with musculoskeletal system health in young and middle-aged adults.

DESIGN

This cross-sectional study used data from 7,515 adults aged 20-59 years, which were obtained from the US NHANES, 2011-2018. Participants' musculoskeletal system health was evaluated on the basis of them having osteopenia, osteoporosis, or sarcopenia.

METHODS

Ordinal regression was used to explore the correlation between income level, exercise volume, and musculoskeletal system health. Mediating effect analysis was used to assess whether the exercise volume affected the impact of income levels on musculoskeletal system health. Ordinal regression and restricted cubic spline curve were used to further analyze the relationship between exercise and income level.

RESULTS

In the analysis of adjusted all covariates, the probability of having good musculoskeletal system health in high-income participants was higher than that of low- or middle-income participants. The probability of having good musculoskeletal system health in the actively exercising group higher than that of the participants exercised insufficiently or sufficiently. Mediating effect of exercise masked the effect of income on musculoskeletal system health. Participants with low income levels tended to spend more time exercising that those who had high income levels; exercise volume and income level had a significant non-linear relationship.

CONCLUSION

The findings presented will help identify young and middle-aged adults who are most at risk of developing musculoskeletal health problem and will likely benefit from certain lifestyle interventions.