The underappreciated role of muscle in health and disease

A systematic review of the effect of semaglutide on lean mass: insights from clinical trials

INTRODUCTION

Semaglutide, a glucagon-like peptide-1 receptor agonist, is associated with significant weight loss, yet its impact on lean body mass remains insufficiently understood. This review investigates the effect of semaglutide on lean mass in the context of obesity management.

METHODOLOGY

This study investigates through different databases (PubMed, Elsevier, and Google Scholar) from 2016 for randomized control trials (RCTs) or observational studies that assessed the use of semaglutide in overweight or obese patients, regardless of whether they have type 2 diabetes or not. The studies compared semaglutide to a placebo or alternative medications.

RESULTS

Six studies with 1,541 overweight or obese adults were included, and significant weight reductions were observed primarily due to fat mass loss. While the lean mass remained stable in some cases, notable reductions ranging from almost 0% to 40% of total weight reduction were observed in others. Noteworthy decreases in lean mass were particularly evident in larger trials, yet the proportion of lean mass relative to total body mass increased, suggesting a positive overall outcome.

CONCLUSION

Semaglutide displays potential for weight loss primarily through fat mass reduction. However, concerns arise from notable reductions in lean mass, especially in trials with a larger number of patients.

Effects of chronic alcohol intoxication on aerobic exercise-induced adaptations in female mice

Chronic alcohol intoxication decreases muscle strength/function and causes mitochondrial dysfunction. Aerobic exercise training improves mitochondrial oxidative capacity and increases muscle mass and strength. Presently, the impact of chronic alcohol on aerobic exercise-induced adaptations was investigated. Female C57BL/6Hsd mice were randomly assigned to one of four groups: control sedentary (CON SED; n = 26), alcohol sedentary (ETOH SED; n = 27), control exercise (CON EX; n = 28), and alcohol exercise (ETOH EX; n = 25). Exercise mice had running wheel access for 2 h a day, 7 days a week. All mice were fed either control or an alcohol-containing liquid diet. Grip strength testing and EchoMRI were performed before and after the interventions. After 6 wk, hindlimb muscles were collected for molecular analyses. A subset of mice performed a treadmill run to fatigue (RTF), then abstained from alcohol for 2 wk and repeated the RTF. Alcohol decreased lean mass and forelimb grip strength compared with control-fed mice. Alcohol blunted the exercise-induced increase in muscle mass (plantaris and soleus), type IIa fiber percentage in the plantaris, and run time to fatigue. Mitochondrial markers (Citrate synthase activity and Complex I-IV, COXIV and Cytochrome C protein expression) were increased with exercise regardless of ETOH in the gastrocnemius but not tibialis anterior muscle. Two weeks of alcohol abstinence improved RTF time in ETOH EX but not in ETOH SED. These data suggest that alcohol impairs some exercise-induced adaptations in skeletal muscle, but not all were negatively affected, indicating that exercise may be a beneficial behavior even while consuming alcohol.NEW & NOTEWORTHY Alcohol consumption during an aerobic exercise training period prevented training-induced increases in run to fatigue time and grip strength. Cessation of alcohol allowed for recovery of endurance performance within 2 wk. The worsened exercise performance after alcohol was unrelated to impairments in markers of mitochondrial health. Therefore, some adaptations to exercise training are impaired with alcohol use (endurance performance, muscle growth, and strength), while others remain mostly unaffected (mitochondrial health).

YTHDF2 governs muscle size through a targeted modulation of proteostasis

The regulation of proteostasis is fundamental for maintenance of muscle mass and function. Activation of the TGF-β pathway drives wasting and premature aging by favoring the proteasomal degradation of structural muscle proteins. Yet, how this critical post-translational mechanism is kept in check to preserve muscle health remains unclear. Here, we reveal the molecular link between the post-transcriptional regulation of m6A-modified mRNA and the modulation of SMAD-dependent TGF-β signaling. We show that the m6A-binding protein YTHDF2 is essential to determining postnatal muscle size. Indeed, muscle-specific genetic deletion of YTHDF2 impairs skeletal muscle growth and abrogates the response to hypertrophic stimuli. We report that YTHDF2 controls the mRNA stability of the ubiquitin ligase ASB2 with consequences on anti-growth gene program activation through SMAD3. Our study identifies a post-transcriptional to post-translational mechanism for the coordination of gene expression in muscle.

Stimulation of muscle protein synthesis with low-dose amino acid composition in older individuals

Essential amino acid (EAA)-based compositions have been shown to be effective stimulators of muscle protein synthesis, but the lower limit of effective dosage is not clear. We have used stable isotope tracer methodology to quantify the response of muscle protein fractional synthetic rate (FSR) to a dose of 3.6 g of a high-leucine composition of EAAs plus arginine in older subjects. Muscle protein FSR increased 0.058%/hour over 3 h following consumption. When account was taken of the total muscle mass, this increase in muscle protein FSR represented approximately 80% of ingested EAAs. We conclude that a low dose of an EAA-based composition can effectively stimulate muscle protein synthesis.

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.

Association between nutritional risk status and both diaphragmatic dysfunction and diaphragm atrophy in medical ıntensive care unit patients

AIM

critical illness often leads to malnutrition and diaphragmatic dysfunction (DD), common in intensive care units (ICU). Ultrasonography (US) is a potent tool for detecting DD. This study examines the connection between malnutrition risk and DD in ICU patients using ultrasonographic diaphragm measurements in medical ICU patients.

METHODS

we assessed nutritional risk using risk screening tools and mid-upper arm circumference measurements (MUAC). Diaphragm atrophy (DA) and DD were evaluated by measuring diaphragmatic excursion (DE), thickness, and thickening fraction (TF) by US. We then compared these diaphragmatic measurements in patients based on their nutritional risk scores.

RESULTS

of the fifty patients studied, 54 % to 78 % were at risk of malnutrition, 28 % exhibited diaphragm atrophy (DA), and 24 % showed DD upon ICU admission. Malnutrition risk diagnosed by all nutritional risk screening tools was significantly more frequent in patients with DD, while diagnosed by MUAC was considerably higher in patients with DA. A total of 16 patients (32 %) died during their ICU stay, with DD, DA, and malnutrition risks (as identified by the mNUTRIC Score) being more prevalent among non-survivors (p < 0.05). Malnutrition risk (as determined by the mNUTRIC Score) was an independent risk factor for DD [OR (95 % CI): 6.6 (1.3-34), p = 0.03].

CONCLUSION

malnutrition risk may be significantly associated with DD and DA in medical ICU patients upon ICU admission.

The Role of Amino Acid Supplementation in Orthopaedic Surgery

The nutritional status of patients undergoing orthopaedic surgery has started to garner increasing attention in published literature. Notable previous evidence has demonstrated the negative effect of malnutrition on outcomes after orthopaedic procedures. Although there has been increased recognition of malnutrition as a risk factor for suboptimal outcomes, the use of nutritional supplementation to mitigate those risks is not well understood. The purpose of this review of most current literature on the topic is to introduce and elucidate the role of amino acid supplementation as a countermeasure to muscle loss and improvement of nutritional status in orthopaedic patients to improve results and outcomes after orthopaedic surgery.

Nutrition as the foundation for successful aging: a focus on dietary protein and omega-3 polyunsaturated fatty acids

Skeletal muscle plays a critical role throughout the aging process. People living with sarcopenia, a progressive and generalized loss of skeletal muscle mass and function, often experience diminished quality of life, which can be attributed to a long period of decline and disability. Therefore, it is important to identify modifiable factors that preserve skeletal muscle and promote successful aging (SA). In this review, SA was defined as (1) low cardiometabolic risk, (2) preservation of physical function, and (3) positive state of wellbeing, with nutrition as an integral component. Several studies identify nutrition, specifically high-quality protein (eg, containing all essential amino acids), and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), as positive regulators of SA. Recently, an additive anabolic effect of protein and n-3 PUFAs has been identified in skeletal muscle of older adults. Evidence further suggests that the additive effect of protein and n-3 PUFAs may project beyond skeletal muscle anabolism and promote SA. The key mechanism(s) behind the enhanced effects of intake of protein and n-3 PUFAs needs to be defined. The first objective of this review is to evaluate skeletal muscle as a driver of cardiometabolic health, physical function, and wellbeing to promote SA. The second objective is to examine observational and interventional evidence of protein and n-3 PUFAs on skeletal muscle to promote SA. The final objective is to propose mechanisms by which combined optimal intake of high-quality protein and n-3 PUFAs likely play a key role in SA. Current evidence suggests that increased intake of protein above the Recommended Dietary Allowance and n-3 PUFAs above the Dietary Guidelines for Americans recommendations for late middle-aged and older adults is required to maintain skeletal muscle mass and to promote SA, potentially through the mechanistical target of rapamycin complex 1 (mTORC1).

Effect of CB1 Receptor Deficiency on Mitochondrial Quality Control Pathways in Gastrocnemius Muscle

This study aims to explore the complex role of cannabinoid type 1 receptor (CB1) signaling in the gastrocnemius muscle, assessing physiological processes in both CB1+/+ and CB1-/- mice. The primary focus is to enhance our understanding of how CB1 contributes to mitochondrial homeostasis. At the tissue level, CB1-/- mice exhibit a substantial miRNA-related alteration in muscle fiber composition, characterized by an enrichment of oxidative fibers. CB1 absence induces a significant increase in the oxidative capacity of muscle, supported by elevated in-gel activity of Complex I and Complex IV of the mitochondrial respiratory chain. The increased oxidative capacity is associated with elevated oxidative stress and impaired antioxidant defense systems. Analysis of mitochondrial biogenesis markers indicates an enhanced capacity for new mitochondria production in CB1-/- mice, possibly adapting to altered muscle fiber composition. Changes in mitochondrial dynamics, mitophagy response, and unfolded protein response (UPR) pathways reveal a dynamic interplay in response to CB1 absence. The interconnected mitochondrial network, influenced by increased fusion and mitochondrial UPR components, underlines the dual role of CB1 in regulating both protein quality control and the generation of new mitochondria. These findings deepen our comprehension of the CB1 impact on muscle physiology, oxidative stress, and MQC processes, highlighting cellular adaptability to CB1-/-. This study paves the way for further exploration of intricate signaling cascades and cross-talk between cellular compartments in the context of CB1 and mitochondrial homeostasis.

The importance of taste on swallowing function

The world's population is aging. Pneumonia is the leading cause of death among the older adults, with aspiration pneumonia being particularly common. Aspiration pneumonia is caused by a decline in swallowing function. Causes can include age-related sarcopenia of swallowing muscles, cognitive decline, cerebrovascular and other diseases or even changes in individual taste preference. Currently, the main treatment approach for dysphagia is resistance training of swallowing-related muscles. This approach has not been effective and establishment of novel methods are required. In this review, we introduce and discuss the relationship between taste, taste preference, carbonation and swallowing function. Taste and preference improve swallowing function. Recently, it has been shown that a carbonated beverage that combines the functionality of a thickening agent, the appeal of taste, and the stimulation of carbonation improves swallowing function. This may be very useful in the recovery of swallowing function. It is important to note that deliciousness is based not only on taste and preference, but also on visual information such as food form. Umami taste receptors are expressed not only in taste buds but also in skeletal muscle and small intestine. These receptors may be involved in homeostasis of the amino acid metabolic network, i.e., the process of amino acid ingestion, intestine absorption, and storage in skeletal muscle. Proper stimulation of umami receptors in organs other than taste buds may help maintain nutritional status and muscle mass. Umami receptors are therefore a potential therapeutic target for dysphagia.

Microbiota derived D-malate inhibits skeletal muscle growth and angiogenesis during aging via acetylation of Cyclin A

Metabolites derived from the intestinal microbiota play an important role in maintaining skeletal muscle growth, function, and metabolism. Here, we found that D-malate (DMA) is produced by mouse intestinal microorganisms and its levels increase during aging. Moreover, we observed that dietary supplementation of 2% DMA inhibits metabolism in mice, resulting in reduced muscle mass, strength, and the number of blood vessels, as well as the skeletal muscle fiber type I/IIb ratio. In vitro assays demonstrate that DMA decreases the proliferation of vascular endothelial cells and suppresses the formation of blood vessels. In vivo, we further demonstrated that boosting angiogenesis by muscular VEGFB injection rescues the inhibitory effects of D-malate on muscle mass and fiber area. By transcriptomics analysis, we identified that the mechanism underlying the effects of DMA depends on the elevated intracellular acetyl-CoA content and increased Cyclin A acetylation rather than redox balance. This study reveals a novel mechanism by which gut microbes impair muscle angiogenesis and may provide a therapeutic target for skeletal muscle dysfunction in cancer or aging.

D-galactose might mediate some of the skeletal muscle hypertrophy-promoting effects of milk-A nutrient to consider for sarcopenia?

Sarcopenia is a process of progressive aging-associated loss of skeletal muscle mass (SMM) recognized as a serious global health issue contributing to frailty and increased all-cause mortality. Exercise and nutritional interventions (particularly intake of dairy products and milk) demonstrate good efficacy, safety, and broad applicability. Here, we propose that at least some of the well-documented favorable effects of milk and milk-derived protein supplements on SMM might be mediated by D-galactose, a monosaccharide present in large quantities in milk in the form of disaccharide lactose (milk sugar). We suggest that ingestion of dairy products results in exposure to D-galactose in concentrations metabolized primarily via the Leloir pathway with the potential to (i) promote anabolic signaling via maintenance of growth factor (e.g., insulin-like growth factor 1 [IGF-1]) receptor mature glycosylation patterns; and (ii) provide extracellular (liver glycogen) and intracellular substrates for short (muscle glycolysis) and long-term (muscle glycogen, intramyocellular lipids) energy availability. Additionally, D-galactose might optimize the metabolic function of skeletal muscles by increasing mitochondrial content and stimulating glucose and fatty acid utilization. The proposed potential of D-galactose to promote the accretion of SMM is discussed in the context of its therapeutic potential in sarcopenia.

Minimalist Training: Is Lower Dosage or Intensity Resistance Training Effective to Improve Physical Fitness? A Narrative Review

BACKGROUND

Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness.

OBJECTIVES

The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise.

METHODS

Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high heterogeneity), a narrative review was selected instead of a systematic meta-analysis approach.

RESULTS

It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises.

CONCLUSION

The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.

'Effects of a home-based bimodal lifestyle intervention in frail patients with end-stage liver disease awaiting orthotopic liver transplantation': study protocol of a non-randomised clinical trial

INTRODUCTION

Patients with end-stage liver disease awaiting orthotopic liver transplantation (OLT) are generally classified as frail due to disease-related malnutrition and a progressive decline in musculoskeletal and aerobic fitness, which is associated with poor pre-OLT, peri-OLT and post-OLT outcomes. However, frailty in these patients may be reversable with adequate exercise and nutritional interventions.

METHODS AND ANALYSIS

Non-randomised clinical trial evaluating the effect of a home-based bimodal lifestyle programme in unfit patients with a preoperative oxygen uptake (VO2) at the ventilatory anaerobic threshold ≤13 mL/kg/min and/or VO2 at peak exercise ≤18 mL/kg/min listed for OLT at the University Medical Center Groningen (UMCG). The programme is patient tailored and comprises high-intensity interval and endurance training, and functional exercises three times per week, combined with nutritional support. Patients will go through two training periods, each lasting 6 weeks.The primary outcome of this study is the impact of the programme on patients' aerobic fitness after the first study period. Secondary outcomes include aerobic capacity after the second study period, changes in sarcopenia, anthropometry, functional mobility, perceived quality of life and fatigue, incidence of hepatic encephalopathy and microbiome composition. Moreover, number and reasons of intercurrent hospitalisations during the study and postoperative outcomes up to 12 months post OLT will be recorded. Finally, feasibility of the programme will be assessed by monitoring the participation rate and reasons for non-participation, number and severity of adverse events, and dropout rate and reasons for dropout.

ETHICS AND DISSEMINATION

This study was approved by the Medical Research Ethics Committee of the UMCG (registration number NL83612.042.23, August 2023) and is registered in the Clinicaltrials.gov register (NCT05853484). Good Clinical Practice guidelines and the principles of the Declaration of Helsinki will be applied. Results of this study will be submitted for presentation at (inter)national congresses and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05853484.

Investigating the relationship between muscle mass and nasal Methicillin-Resistant Staphylococcus aureus (MRSA) colonization: Analysis of the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is associated with an increased risk of infection disease. Low muscle mass has been linked to higher levels of inflammatory markers and weakened immune response, which may impact the susceptibility to nasal MRSA colonization. The relationship between muscle function and immune response to pathogens may be bidirectional. This study investigates the association between muscle mass and nasal MRSA colonization in adults.

METHODS

The present cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2001 and 2004. Appendicular skeletal muscle mass (ASM) adjusted by body mass index (BMI) (ASM/BMI) was used to evaluate muscle mass. Multivariate logistic regression, adjusted for demographic and infection factors, was used to analyze the association between muscle mass and nasal colonization by MRSA. A subgroup analysis based on age and gender was performed to assess the impact of muscle mass on nasal MRSA colonization.

RESULTS

Nasal MRSA colonization was more prevalent in females, those with smaller household sizes, lower income, lower ASM/BMI, those who had stayed in healthcare facilities in the past 12 months, and individuals with diabetes and smoking habits. After adjusting for confounding factors, a dose-dependent association was found between decreasing quartiles of ASM/BMI and the risk of nasal MRSA colonization (p < 0.05). Additionally, per 1 unit increase in ASM/BMI was related to a 64% lower risk of nasal MRSA colonization.

CONCLUSIONS

This study suggests a significant negative correlation between ASM/BMI and the risk of nasal MRSA colonization. However, more prospective studies are required to investigate the causal relationship between muscle mass and colonization.

Association between total and animal proteins with risk of fracture: A systematic review and dose-response meta-analysis of cohort studies

Previous cohort studies have indicated that consumption of total and animal proteins are related to fracture risk; however, results were inconclusive. This dose-dependent review sought to summarize the earlier evidence regarding the relation between total and animal proteins and fracture risk. We searched Scopus, PubMed, and Web of Science until July 2023 for original research articles examining the association of certain types of proteins and the incidence of all fractures in general adults. Summary relative risks (RRs) were calculated using random effects analysis to examine the relation between each certain amount (g/day) increment of total and animal protein and fracture risk. Twenty cohort studies with serious to moderate risk of bias involving 780,322 individuals were included. There was a non-statistically significant relation between intake of animal proteins and dairy products and all fracture risk. However, 43% and 5% decreased incidence of fracture was obtained with total protein (RR, 0.57; 95%CI, 0.36 to 0.93; per 100 g/day) and fish (RR, 0.95; 95%CI, 0.91 to 0.99; per 15 g/day) intake. Every 100 g/day total and animal protein consumption and every 15 g/day fish consumption were linked to 48%, 50%, and 5% lower hip fracture risk. Greater dietary animal protein intake might reduce risk of hip but not fracture at any site. We obtained a lower risk of any or hip fracture with greater total protein (per 100 g/day) and fish (per 15 g/day) intake. No evidence was obtained that higher intake of dairy could decrease risk of fracture.

A Simple Device for Measuring Sit-to-Stand Movements and Cardio-Metabolic Diseases: A Cross-Sectional Study in a Health Check-Up Population Over 20 Years Old

Introduction Several studies have reported the usefulness of measuring lower limb muscle strength through the motion of standing up using a reaction force measuring device positioned on the ground. There is inadequate information on the association between cardiovascular disease risk factors and ground reaction force (GRF) during standing up. Therefore, this study estimated the association between GRF by sit-to-stand movements and cardiovascular disease risk factors in a health check-up population. Methods This cross-sectional study included 1,182 healthy participants without chronic diseases who underwent periodic health check-ups from August 2019 to December 2020. The study included individuals aged ≥20 years who underwent a standing test from an initial seated position in a chair. A sit-to-stand force analyzer was used to measure GRF, and health status information was collected at enrollment. The relationships between blood test data and each measurement obtained from GRF measurements (forth/body mass (F/M), rate of forth development/body mass (RFD/M), and stable time) were parsed according to sex using linear regression analysis coordinated by age. GRF measurements and their relationships with cardiovascular disease risk factors were assessed using logistic regression analysis, adjusted for age and sex. Results A total of 1,182 participants was included in this study, with male participants accounting for 61.5%. The study participants had a median age of 57.0 years (IQR: 47.0-63.0). After adjusting for age, F/M was positively associated with high-density lipoprotein cholesterol in male (β=22.59, p<0.001) and female participants (β=20.35, p=0.011) and negatively associated with plasma glucose in male (β=-16.25, p=0.008) and female participants (β=-18.78, p=0.028). Stable time (time required to be stabilize after standing up movement) was positively associated with hemoglobin A1c levels in male (β=0.55, p=0.001) and female participants (β=0.56, p=0.036). Logistic regression analysis adjusted by age and sex showed that a lower F/M ratio was associated with hypertension, hyperlipidemia, and diabetes mellitus (adjusted odds ratio (aOR) =1.60, p=0.01; aOR=1.75, p=0.001; and aOR=2.23, p=0.002, respectively). Lower RFD/M was associated with hyperlipidemia and diabetes mellitus (aOR=1.46, p=0.013 and aOR=1.63, p=0.045, respectively). A shorter stable time was associated with diabetes mellitus (aOR=0.39, p<0.001). Conclusions These findings suggest that lower limb function impairment, as assessed via standing-up movements using a GRF-measuring device, may relate to cardiovascular disease. Further research is needed to confirm this association.

Sarcopenia of Ageing: Does a Healthier Lifestyle Matter in Reversing the Trajectory? A Brief Narrative Review and a Call for Action in Saudi Arabia

The concept of health span is an emerging topic in recent years, with a truly palpable relevance to public health. With ageing comes a loss of skeletal muscle mass, strength, and performance, which is termed as sarcopenia. Sarcopenia is a major public health concern and poses a challenge to health-care systems. Modifiable lifestyle factors may be linked to the course of sarcopenia progression. Many countries developed diagnostic tools to accurately detect sarcopenia for its prevention, delay, or treatment. However, to date, there is no sufficient information regarding the status of sarcopenia in Saudi Arabia. The review aims to discuss sarcopenia and relevant updates in research and literature, the association with modifiable lifestyle factors, the implications of sarcopenia in a rapidly developing country such as Saudi Arabia, and the current state and need for research in Saudi Arabia in this domain along with future directions in combating this disease.

Associations of plasma retinol and α-tocopherol levels with skeletal muscle health in Chinese children

Childhood is a critical period for muscle accumulation. Studies in elders have reported that antioxidant vitamins could improve muscle health. However, limited studies have assessed such associations in children. This study included 243 boys and 183 girls. A seventy-nine-item FFQ was used to investigate dietary nutrients intake. Plasma levels of retinol and α-tocopherol were measured using high-performance liquid chromatography with MS. Dual X-ray absorptiometry was used to assess appendicular skeletal muscle mass (ASM) and total body fat. The ASM index (ASMI) and ASMI Z-score were then calculated. Hand grip strength was measured using a Jamar® Plus+ Hand Dynamometer. Fully adjusted multiple linear regression models showed that for each unit increase in plasma retinol content, ASM, ASMI, left HGS and ASMI Z-score increased by 2·43 × 10-3 kg, 1·33 × 10-3 kg/m2, 3·72 × 10-3 kg and 2·45 × 10-3 in girls, respectively (P < 0·001-0·050). ANCOVA revealed a dose-response relationship between tertiles of plasma retinol level and muscle indicators (Ptrend: 0·001-0·007). The percentage differences between the top and bottom tertiles were 8·38 %, 6·26 %, 13·2 %, 12·1 % and 116 % for ASM, ASMI, left HGS, right HGS and ASMI Z-score in girls, respectively (Pdiff: 0·005-0·020). No such associations were observed in boys. Plasma α-tocopherol levels were not correlated with muscle indicators in either sex. In conclusion, high circulating retinol levels are positively associated with muscle mass and strength in school-age girls.

Myotube growth is associated with cancer-like metabolic reprogramming and is limited by phosphoglycerate dehydrogenase

The Warburg effect links growth and glycolysis in cancer. A key purpose of the Warburg effect is to generate glycolytic intermediates for anabolic reactions, such as nucleotides → RNA/DNA and amino acids → protein synthesis. The aim of this study was to investigate whether a similar 'glycolysis-for-anabolism' metabolic reprogramming also occurs in hypertrophying skeletal muscle. To interrogate this, we first induced C2C12 myotube hypertrophy with IGF-1. We then added 14C glucose to the differentiation medium and measured radioactivity in isolated protein and RNA to establish whether 14C had entered anabolism. We found that especially protein became radioactive, suggesting a glucose → glycolytic intermediates → non-essential amino acid(s) → protein series of reactions, the rate of which was increased by IGF-1. Next, to investigate the importance of glycolytic flux and non-essential amino acid synthesis for myotube hypertrophy, we exposed C2C12 and primary mouse myotubes to the glycolysis inhibitor 2-Deoxy-d-glucose (2DG). We found that inhibiting glycolysis lowered C2C12 and primary myotube size. Similarly, siRNA silencing of PHGDH, the key enzyme of the serine biosynthesis pathway, decreased C2C12 and primary myotube size; whereas retroviral PHGDH overexpression increased C2C12 myotube size. Together these results suggest that glycolysis is important for hypertrophying myotubes, which reprogram their metabolism to facilitate anabolism, similar to cancer cells.

The Structural Adaptations That Mediate Disuse-Induced Atrophy of Skeletal Muscle

The maintenance of skeletal muscle mass plays a fundamental role in health and issues associated with quality of life. Mechanical signals are one of the most potent regulators of muscle mass, with a decrease in mechanical loading leading to a decrease in muscle mass. This concept has been supported by a plethora of human- and animal-based studies over the past 100 years and has resulted in the commonly used term of 'disuse atrophy'. These same studies have also provided a great deal of insight into the structural adaptations that mediate disuse-induced atrophy. For instance, disuse results in radial atrophy of fascicles, and this is driven, at least in part, by radial atrophy of the muscle fibers. However, the ultrastructural adaptations that mediate these changes remain far from defined. Indeed, even the most basic questions, such as whether the radial atrophy of muscle fibers is driven by the radial atrophy of myofibrils and/or myofibril hypoplasia, have yet to be answered. In this review, we thoroughly summarize what is known about the macroscopic, microscopic, and ultrastructural adaptations that mediated disuse-induced atrophy and highlight some of the major gaps in knowledge that need to be filled.

Evaluating Nutritional Risk Factors for Delirium in Intensive-Care-Unit Patients: Present Insights and Prospects for Future Research

Malnutrition, hypercatabolism, and metabolic changes are well-established risk factors for delirium in critically ill patients. Although the exact mechanisms are not fully understood, there is mounting evidence suggesting that malnutrition can cause a variety of changes that contribute to delirium, such as electrolyte imbalances, immune dysfunction, and alterations in drug metabolism. Therefore, a comprehensive metabolic and malnutrition assessment, along with appropriate nutritional support, may help to prevent or ameliorate malnutrition, reduce hypercatabolism, and improve overall physiological function, ultimately lowering the risk of delirium. For this aim, bioelectrical impedance analysis can represent a valuable strategy. Further research into the underlying mechanisms and nutritional risk factors for delirium is crucial to developing more effective prevention strategies. Understanding these processes will allow clinicians to personalize treatment plans for individual patients, leading to improved outcomes and quality of life in the intensive-care-unit survivors.

Nutritional strategies to optimise musculoskeletal health for fall and fracture prevention: Looking beyond calcium, vitamin D and protein

Falls and osteoporotic fractures are a major public health problem, particularly among older adults. A third of individuals aged 65 years and over fall at least once each year, with up to 20 % of these resulting in serious injury, including fracture. In conjunction with regular exercise, the importance of diet for musculoskeletal health has largely focused upon calcium, vitamin D, and protein, particularly in the context of preventing falls and fractures. Whilst there is evidence for the benefits of these nutrients for musculoskeletal health, other aspects of the diet remain largely underexplored. For example, vegetables are rich sources of macro- and micronutrients that are essential for muscle function and bone health, which are key factors in the prevention of falls and fractures. Recent work has highlighted the importance of nutrients such as vegetable-derived nitrate and vitamin K1 in optimising muscle strength, physical function, and bone quality. In the context of dietary patterns, vegan/plant-based diets have recently gained popularity due to perceived health benefits, animal welfare, or to tackle climate change. The elimination and/or substitution of animal-based products for plant foods (without careful planning and/or expert dietary guidance) could, however, have long-term negative musculoskeletal consequences; a trend uncovered by recent evidence. Within the overarching theme of nutrition for fall and fracture prevention in older populations, the aim of this review is to (i) summarise the current evidence for calcium, vitamin D and protein; (ii) describe the importance of vegetables and selected nutrients, such as nitrate and vitamin K1, for muscle function and bone structural integrity; and (iii) highlight current evidence around different dietary patterns (e.g., plant-based, diet quality, data driven approaches) and their impact on musculoskeletal health.

Therapeutic application of natural compounds for skeletal muscle-associated metabolic disorders: A review on diabetes perspective

Skeletal muscle (SM) plays a vital role in energy and glucose metabolism by regulating insulin sensitivity, glucose uptake, and blood glucose homeostasis. Impaired SM metabolism is strongly linked to several diseases, particularly type 2 diabetes (T2D). Insulin resistance in SM may result from the impaired activities of insulin receptor tyrosine kinase, insulin receptor substrate 1, phosphoinositide 3-kinase, and AKT pathways. This review briefly discusses SM myogenesis and the critical roles that SM plays in insulin resistance and T2D. The pharmacological targets of T2D which are associated with SM metabolism, such as DPP4, PTB1B, SGLT, PPARγ, and GLP-1R, and their potential modulators/inhibitors, especially natural compounds, are discussed in detail. This review highlights the significance of SM in metabolic disorders and the therapeutic potential of natural compounds in targeting SM-associated T2D targets. It may provide novel insights for the future development of anti-diabetic drug therapies. We believe that scientists working on T2D therapies will benefit from this review by enhancing their knowledge and updating their understanding of the subject.

The Effect of Downhill Running on Quadriceps Muscle in Growth-Restricted Mice

INTRODUCTION

Growth restriction (GR) reduces ribosome abundance and skeletal muscle mass in mice. A reduction in skeletal muscle mass increases the risk of frailty and is associated with high morbidity and mortality rates. As eccentric type exercise increases muscle mass, this investigation aimed to determine if eccentric loading of skeletal muscle via downhill running (DHR) increased muscle mass in GR mice.

METHODS

Mice were growth-restricted either gestational undernutrition (GUN, n = 8 litters), postnatal undernutrition (PUN, n = 8 litters), or were not restricted (CON, n = 8 litters) via a validated cross-fostering nutritive model. On postnatal day (PN) 21, all mice were weaned to a healthy diet, isolating the period of GR to early life as seen in humans. At PN45, mice were assigned to either a DHR (CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) or sedentary (SED: CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) group. Downhill running (16% decline: 18 m·min -1 ) was performed in 30-min bouts, three times per week, for 12 wk on a rodent treadmill. At PN129, the quadriceps femoris was dissected and evaluated for mass, myofiber size and type, and molecular markers of growth.

RESULTS

Following training, CON-DHR mice having larger cells than CON-SED, GUN-SED, PUN-SED, and PUN-DHR mice ( P < 0.05). The PUN group (as compared with CON) had reduced body mass ( P < 0.001), upstream binding factor abundance ( P = 0.012), phosphor-mTOR ( P < 0.001), and quadriceps mass ( P = 0.02). The GUN and PUN groups had increased MuRF1 abundance ( P < 0.001) compared with CON ( P < 0.001).

CONCLUSIONS

The blunted response to training suggests GR mice may have anabolic resistance when exposed to eccentric type exercise.

Association between longitudinal dietary patterns and changes in obesity: a population-based cohort study

Introduction

Research on the trajectory of dietary patterns and changes in obesity has been inconclusive.

Methods

This study described the dietary intake and adiposity trajectories of Chinese adults and assessed the association between dietary trajectories and changes in body mass index (BMI) and waist-to-hip ratio (WHR). We used data from 3, 643 adults who participated in the China Health and Nutrition Survey from 1997 to 2015. Detailed dietary data were collected by conducting three consecutive 24-h recalls. Multitrajectories of diet scores were identified by a group-based multitrajectory method. We described the change in BMI and WHR using group-based trajectory modeling. We assessed the associations between dietary trajectories and changes in people with obesity using a logistic regression model.

Results

Our study revealed four trajectories of low-carbohydrate (LCD) and low-fat diet (LFD) scores. Three adiposity trajectories were identified according to the baseline level and developmental trend of BMI and WHR. Compared with the reference group, which was characterized by sustained healthy dietary habits with healthy diet scores at baseline and sustained maintenance of healthy diet scores, the other three diet trajectories had a higher risk of falling into the adverse adiposity trajectory.

Discussion

Maintaining a healthy LCD and LFD can markedly decrease the risk of adiposity.

Modification of resting metabolism, body composition, and muscle strength after resolution of coronavirus disease 2019

BACKGROUND & AIMS

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes changes that can influence human metabolism and modify the distribution of body compartments. We aimed to describe the clinical findings of changes in resting metabolism, muscle strength, and body composition in nonhospitalized patients after being diagnosed with coronavirus disease 2019 (COVID-19).

METHODS

Physically active patients were evaluated at a nutrition clinic, and indirect calorimetry (IC) and body composition analysis using portable ultrasound were performed. After a routine appointment, all patients were instructed to inform the staff if they tested positive for SARS-CoV-2 infection. Our sample included individuals diagnosed with COVID-19, confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR), within 7 days of the routine appointment. After an average incubation period of 14-21 days, in which there was no proven transmission of disease by RT-PCR, all of the patients were re-evaluated.

RESULTS

A total of 38 volunteers (63.2% female) completed the study and were included in the analysis. The mean age of the participants was 37.3 ± 8.8 years. The comparison between pre- and post-COVID-19 stratified by sex demonstrated significant reduction in the RMR and RMR adjusted for weight (p < 0.0001) for both groups. Regarding body composition, there was a significant increase observed in fat mass in men (p < 0.002) and women (p < 0.01), and a significant reduction observed in fat-free mass (men: p < 0.002; women: p < 0.001) and skeletal muscle mass (men: p = 0.003; women: p < 0.0001). There was a significant difference between the change in the RMR measured by IC (p < 0.0001) and that calculated by the predictive equation of Cunningham (1980) (p < 0.0001), whereas the Harris and Benedict (1918) and Mifflin (1990) equations exhibited no difference. However, the mean difference in RMR between the post- and pre-COVID-19 calculated by the Cunningham equation was -40.4 kcal/day (95% confidence interval [CI]: -56.38 to -24.45), whereas the mean difference measured by IC was -362.3 kcal/day (95% CI: -452.7 to -271.9).

CONCLUSION

This study describes the trends in the RMR, and body composition in individuals with COVID-19 who were not hospitalized from the pre-COVID-19 period to the post-COVID-19 period. A significant reduction in resting energy expenditure, and loss of fat-free mass and muscle mass in the post-COVID-19 period were observed in both men and women.

The effect of fish oil supplementation on resistance training-induced adaptations

BACKGROUND

Resistance exercise training (RET) is a common and well-established method to induce hypertrophy and improvement in strength. Interestingly, fish oil supplementation (FOS) may augment RET-induced adaptations. However, few studies have been conducted on young, healthy adults.

METHODS

A randomized, placebo-controlled design was used to determine the effect of FOS, a concentrated source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), compared to placebo (PL) on RET-induced adaptations following a 10-week RET program (3 days·week^-1). Body composition was measured by dual-energy x-ray absorptiometry (LBM, fat mass [FM], percent body fat [%BF]) and strength was measured by 1-repetition maximum barbell back squat (1RM_SQT) and bench press (1RM_BP) at PRE (week 0) and POST (10 weeks). Supplement compliance was assessed via self-report and bottle collection every two weeks and via fatty acid dried blood spot collection at PRE and POST. An a priori α-level of 0.05 was used to determine statistical significance and Cohen's d was used to quantify effect sizes (ES).

RESULTS

Twenty-one of 28 male and female participants (FOS, n = 10 [4 withdrawals]; PL, n = 11 [3 withdrawals]) completed the 10-week progressive RET program and PRE/POST measurements. After 10-weeks, blood EPA+DHA substantially increased in the FOS group (+109.7%, p< .001) and did not change in the PL group (+1.3%, p = .938). Similar between-group changes in LBM (FOS: +3.4%, PL: +2.4%, p = .457), FM (FOS: -5.2%, PL: 0.0%, p = .092), and %BF (FOS: -5.9%, PL: -2.5%, p = .136) were observed, although, the between-group ES was considered large for FM (d = 0.84). Absolute and relative (kg·kg [body mass]^-1) 1RM_BP was significantly higher in the FOS group compared to PL (FOS: +17.7% vs. PL: +9.7%, p = .047; FOS: +17.6% vs. PL: +7.3%, p = .011; respectively), whereas absolute 1RM_SQT was similar between conditions (FOS: +28.8% vs. PL: +20.5%, p = .191). Relative 1RM_SQT was higher in the FOS group (FOS: +29.3% vs. PL: +17.9%, p = .045).

CONCLUSIONS

When combined with RET, FOS improves absolute and relative 1RM upper-body and relative 1RM lower-body strength to a greater extent than that observed in the PL group of young, recreationally trained adults.

PROMISE: effect of protein supplementation on fat-free mass preservation after bariatric surgery, a randomized double-blind placebo-controlled trial

INTRODUCTION

Protein malnutrition after bariatric surgery is a severe complication and leads to significant morbidity. Previous studies have shown that protein intake and physical activity are the most important factors in the preservation of fat-free mass during weight loss. Low protein intake is very common in patients undergoing bariatric surgery despite dietary counseling. Protein powder supplements might help patients to achieve the protein intake recommendations after bariatric surgery and could therefore contribute to preserve fat-free mass. This double-blind randomized placebo-controlled intervention study aims to assess the effect of a daily consumed clear protein powder shake during the first 6 months after bariatric surgery on fat-free mass loss in the first 12 months after laparoscopic Roux-en-Y gastric bypass (LRYGB).

METHODS AND ANALYSIS

Inclusion will take place at the outpatient clinic of the bariatric expertise center for obesity of the Maasstad Hospital. Patients will be randomly assigned to either the intervention or control group before surgery. The intervention group will receive a clear protein powder shake of 200 ml containing 20 g of whey protein dissolved in water which should be taken daily during the first 6 months after LRYGB on top of their normal postoperative diet. The control group will receive an isocaloric, clear, placebo shake containing maltodextrine. Postoperative rehabilitation and physiotherapeutical guidance will be standardized and similar in both groups. Also, both groups will receive the same dietary advice from specialized dieticians. The main study parameter is the percentage of fat-free mass loss 6 months after surgery, assessed by multi-frequency bioelectrical impedance analysis (MF-BIA).

ETHICS AND DISSEMINATION

The protocol, version 2 (February 20, 2022) has been approved by the Medical Research Ethics Committees United (MEC-U) (NL 80414.100.22). The results of this study will be submitted to peer-reviewed journals.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05570474. Registered on October 5, 2022.

Microgravity-induced skeletal muscle atrophy in women and men: implications for long-duration spaceflights to the Moon and Mars

The inclusion of women on spaceflights has historically been limited. Recently, the first woman who will travel to the Moon was selected, and more women are participating in long-duration spaceflights. However, physiological data from real and simulated microgravity exposure are limited in women. This investigation studied women (n = 8, 34 ± 1 yr) and men (n = 9, 32 ± 1 yr) who underwent 2 (women) or 3 (men) mo of simulated microgravity (6° head-down tilt bed rest). Quadriceps and triceps surae muscle volumes were assessed via MRI before bed rest, bed rest day 29 (BR29, women and men), bed rest day 57 (BR57, women), and bed rest day 89 (BR89, men). Volume of both muscle groups decreased (P < 0.05) in women and men at all bed rest timepoints. Quadriceps muscle volume loss in women was greater than men at 1 mo (BR29: -17% vs. -10%, P < 0.05) and this 1-mo loss for women was similar to men at 3 mo (BR89: -18%, P > 0.05). In addition, the loss in women at 2 mo (BR57: -21%) exceeded men at 3 mo (P < 0.05). For the triceps surae, there was a trend for greater muscle volume loss in women compared with men at 1 mo (BR29: -18% vs. -16%, P = 0.08), and loss in women at 2 mo was similar to men at 3 mo (BR57: -29%, BR89: -29%, P > 0.05). The collective evidence suggests that women experience greater lower limb muscle atrophy than men at least through the first 4 mo of microgravity exposure. More sex-specific microgravity studies are needed to help protect the health of women traveling on long-duration orbital and interplanetary spaceflights.NEW & NOTEWORTHY This study adds to the limited evidence regarding sex-specific responses to real or simulated microgravity exposure, which collectively suggests a sex-specific muscle atrophy profile, with women losing more than men at least through the first 4 mo of weightlessness. Considering the increase in women being selected for space missions, including the first women to travel to the Moon, more physiological data on women in response to microgravity are needed.

Dose-Response of Myofibrillar Protein Synthesis To Ingested Whey Protein During Energy Restriction in Overweight Postmenopausal Women: A Randomized, Controlled Trial

BACKGROUND

Diet-induced weight loss is associated with a decline in lean body mass, as mediated by an impaired response of muscle protein synthesis (MPS). The dose-response of MPS to ingested protein, with or without resistance exercise, is well characterized during energy balance but limited data exist under conditions of energy restriction in clinical populations.

OBJECTIVE

To determine the dose-response of MPS to ingested whey protein following short-term diet-induced energy restriction in overweight, postmenopausal, women at rest and postexercise.

DESIGN

Forty middle-aged (58.6±0.4 y), overweight (BMI: 28.6±0.4), postmenopausal women were randomly assigned to 1 of 4 groups: Three groups underwent 5 d of energy restriction (∼800 kcal/d). On day 6, participants performed a unilateral leg resistance exercise bout before ingesting either a bolus of 15g (ERW15, n = 10), 35g (ERW35, n = 10) or 60g (ERW60, n = 10) of whey protein. The fourth group (n = 10) ingested a 35g whey protein bolus after 5 d of an energy balanced diet (EBW35, n = 10). Myofibrillar fractional synthetic rate (FSR) was calculated under basal, fed (FED) and postexercise (FED-EX) conditions by combining an L-[ring-13C6] phenylalanine tracer infusion with the collection of bilateral muscle biopsies.

RESULTS

Myofibrillar FSR was greater in ERW35 (0.043±0.003%/h, P = 0.013) and ERW60 (0.042±0.003%/h, P = 0.026) than ERW15 (0.032 ± 0.003%/h), with no differences between ERW35 and ERW60 (P = 1.000). Myofibrillar FSR was greater in FED (0.044 ± 0.003%/h, P < 0.001) and FED-EX (0.048 ± 0.003%/h, P < 0.001) than BASAL (0.027 ± 0.003%/h), but no differences were detected between FED and FED-EX (P = 0.732) conditions. No differences in myofibrillar FSR were observed between EBW35 (0.042 ± 0.003%/h) and ERW35 (0.043 ± 0.003%/h, P = 0.744).

CONCLUSION

A 35 g dose of whey protein, ingested with or without resistance exercise, is sufficient to stimulate a maximal acute response of MPS following short-term energy restriction in overweight, postmenopausal women, and thus may provide a per serving protein recommendation to mitigate muscle loss during a weight loss program.

TRIAL REGISTRY

clinicaltrials.gov (ID: NCT03326284).

Muscle Quality Index is inversely associated with psychosocial variables among Chilean adolescents

A good muscle quality index (MQI) may have an inverse relationship with psychosocial variables of depression, anxiety, and stress in adolescents. Unfortunately, little scientific evidence has related MQI to psychosocial variables in this population. Therefore, this research aimed to determine the relationship between the MQI and psychosocial variables of depression, anxiety, and stress in Chilean adolescents. In this quantitative correlational design study, sixty adolescents participated voluntarily (mean ± standard deviation [SD]: age 15.11 ± 1.78 years). Anthropometric parameters, prehensile strength, MQI, and psychosocial variables were evaluated. The results showed that adolescents with high levels of MQI presented lower levels of depression (7.50 ± 6.06 vs. 10.97 ± 5.94), anxiety (5.64 ± 4.81 vs. 9.66 ± 5.12), and stress (6.79 ± 5.09 vs. 10 ± 5.58), in addition to reported lower abdominal obesity (WtHR, 0.47 ± 0.07 vs. 0.52 ± 0.07) than those with low levels of MQI. The group with high levels of MQI reported a higher prevalence of nonanxiety (81.3%, p = 0.031) and a lower prevalence of abdominal obesity (55.8%, p = 0.023). Likewise, a significant inverse association was evidenced between MQI and depression (β; -6.18, 95% CI; -10.11: -2.25, p = 0.003), anxiety (β; -6.61, 95% CI; -9.83: -3.39, p < 0.001) and stress (β; -4.90, 95% CI; -8.49: -1.32 p = 0.008). In conclusion, the results suggest that high levels of MQI are associated with a higher prevalence of nonanxiety in adolescents and a significant inverse association between MQI and levels of depression, anxiety, and stress.

Water Intake and Handgrip Strength in US Adults: A Cross-Sectional Study Based on NHANES 2011-2014 Data

This study aimed to examine the relationship between daily total intake of water (DTIW) and handgrip strength (HGS) among US adults and to explore the impact of water intake on muscle function and health, providing a reference for public health policies and health education. Using the data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, a cross-sectional survey design was adopted to analyze 5427 adults (48.37% female and 51.63% male) aged 20 years and above. DTIW was assessed using two non-consecutive 24 h dietary recall interviews, and the HGS level was measured using a Takei Dynamometer. Weighted generalized linear regression models and restricted cubic spline plots were used to analyze the linear and nonlinear associations between DTIW and HGS level and to conduct a gender subgroup analysis and an interaction effect test. The results showed that there were significant differences in HGS and other characteristics among different quartile groups of DTIW (p < 0.05). There was a significant nonlinear trend (exhibiting an inverted U-curve) between DTIW and HGS (p for nonlinear = 0.0044), with a cut-off point of 2663 g/day. Gender subgroup analysis showed that the nonlinear trend (exhibiting an inverted U-curve) was significant only in males (p for nonlinear = 0.0016), with a cut-off point of 2595 g/day. None of the stratified variables had an interaction effect on the association between DTIW and HGS (p for interaction > 0.05). In conclusion, this study found a nonlinear association between DTIW and HGS levels, as well as a gender difference. This finding provides new clues and directions for exploring the mechanism of the impact of DTIW on muscle function and health and also provides new evidence and suggestions for adults to adjust their water intake reasonably.

Nutritional Value of Yogurt as a Protein Source: Digestibility/Absorbability and Effects on Skeletal Muscle

Yogurt is a traditional fermented food that is accepted worldwide for its high palatability and various health values. The milk protein contained in yogurt exhibits different physical and biological properties from those of non-fermented milk protein due to the fermentation and manufacturing processes. These differences are suggested to affect the time it takes to digest and absorb milk protein, which in turn will influence the blood levels of amino acids and/or hormones, such as insulin, and thereby, the rate of skeletal muscle protein synthesis via the activation of intracellular signaling, such as the mTORC1 pathway. In addition, based on the relationship between gut microbiota and skeletal muscle conditions, yogurt, including lactic acid bacteria and its metabolites, has been evaluated for its role as a protein source. However, the substantial value of yogurt as a protein source and the additional health benefits on skeletal muscle are not fully understood. The purpose of this review is to summarize the research to date on the digestion and absorption characteristics of yogurt protein, its effect on skeletal muscle, and the contribution of lactic acid bacterial fermentation to these effects.

Dietary protein recommendations to support healthy muscle ageing in the 21st century and beyond: considerations and future directions

This review explores the evolution of dietary protein intake requirements and recommendations, with a focus on skeletal muscle remodelling to support healthy ageing based on presentations at the 2023 Nutrition Society summer conference. In this review, we describe the role of dietary protein for metabolic health and ageing muscle, explain the origins of protein and amino acid (AA) requirements and discuss current recommendations for dietary protein intake, which currently sits at about 0⋅8 g/kg/d. We also critique existing (e.g. nitrogen balance) and contemporary (e.g. indicator AA oxidation) methods to determine protein/AA intake requirements and suggest that existing methods may underestimate requirements, with more contemporary assessments indicating protein recommendations may need to be increased to >1⋅0 g/kg/d. One example of evolution in dietary protein guidance is the transition from protein requirements to recommendations. Hence, we discuss the refinement of protein/AA requirements for skeletal muscle maintenance with advanced age beyond simply the dose (e.g. source, type, quality, timing, pattern, nutrient co-ingestion) and explore the efficacy and sustainability of alternative protein sources beyond animal-based proteins to facilitate skeletal muscle remodelling in older age. We conclude that, whilst a growing body of research has demonstrated that animal-free protein sources can effectively stimulate and support muscle remodelling in a manner that is comparable to animal-based proteins, food systems need to sustainably provide a diversity of both plant and animal source foods, not least for their protein content but other vital nutrients. Finally, we propose some priority research directions for the field of protein nutrition and healthy ageing.

Prediction equations to estimate muscle mass using anthropometric data: a systematic review

CONTEXT

Reduced muscle mass is linked to poor outcomes in both inpatients and outpatients, highlighting the importance of muscle mass assessment in clinical practice. However, laboratory methods to assess muscle mass are not yet feasible for routine use in clinical practice because of limited availability and high costs.

OBJECTIVE

This work aims to review the literature on muscle mass prediction by anthropometric equations in adults or older people.

DATA SOURCES

The following databases were searched for observational studies published until June 2022: MEDLINE, Embase, Scopus, SPORTDiscus, and Web of Science.

DATA EXTRACTION

Of 6437 articles initially identified, 63 met the inclusion criteria for this review. Four independent reviewers, working in pairs, selected and extracted data from those articles.

DATA ANALYSIS

Two studies reported new equations for prediction of skeletal muscle mass: 10 equations for free-fat mass and lean soft tissue, 22 for appendicular lean mass, 7 for upper-body muscle mass, and 7 for lower-body muscle mass. Twenty-one studies validated previously proposed equations. This systematic review shows there are numerous equations in the literature for muscle mass prediction, and most are validated for healthy adults. However, many equations were not always accurate and validated in all groups, especially people with obesity, undernourished people, and older people. Moreover, in some studies, it was unclear if fat-free mass or lean soft tissue had been assessed because of an imprecise description of muscle mass terminology.

CONCLUSION

This systematic review identified several feasible, practical, and low-cost equations for muscle mass prediction, some of which have excellent accuracy in healthy adults, older people, women, and athletes. Malnourished individuals and people with obesity were understudied in the literature, as were older people, for whom there are only equations for appendicular lean mass.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42021257200.

Association between grip strength and stress urinary incontinence of NHANES 2011-2014

OBJECTIVES

To investigate the association between grip strength (GS) and relative grip strength (rGS) with the prevalence and severity risk of SUI.

METHODS

Female patients were retrieved from the NHANES 2011-2014. GS was measured using a digital hand dynamometer, rGS was defined as grip strength divided by BMI. Samples were classified into four groups based on quartiles of GS and rGS distribution (Q1-Q4)。Logistic regression models were established to detect the relationship between GS or rGS and SUI. The potential bias of baseline variables between SUI and non-SUI groups was controlled by performing the propensity score matching (PSM).

RESULTS

A total of 4263 samples were included, with 3085 (85%) people in non-SUI group and 1178 (27.6%) people in SUI group. GS and rGS levels of people without SUI were higher than that of SUI patients. Monthly SUI patients' GS and rGS levels were higher than weekly SUI patients' level. Logistic regression analysis showed that risks of prevalence and severity of SUI decreased with increasing levels of GS and rGS. rGS was found to have a stronger association with SUI than GS [prevalence: GS: Q4 vs. Q1: aOR = 0.633, 95%CI = 0.508-0.789, p < 0.001; rGS: Q4 vs. Q1: aOR = 0.365, 95%CI = 0.290-0.459, p < 0.001; severity: GS: Q4 vs. Q1: aOR = 0.727, 95%CI = 0.600-0.881, p = 0.001; rGS: Q4 vs. Q1: aOR = 0.371, 95%CI = 0.282-0.488, p < 0.001]. The results of PSM confirmed that GS and rGS were correlated with SUI.

CONCLUSIONS

Lower levels of GS and rGS are associated with an increased prevalence and severity risk of SUI.

Estimation of 24-hour urinary creatinine excretion from patient variables: A novel approach to identify patients with low muscle mass and malnutrition and relationship to outcomes

BACKGROUND

Low muscle mass has been correlated with adverse outcomes in patients who are critically ill. Methods to identify low muscularity such as computed tomography scans or bioelectrical impedance analyses are impractical for admission screening. Urinary creatinine excretion (UCE) and creatinine height index (CHI) are associated with muscularity and outcomes but require a 24-h urine collection. The estimation of UCE from patient variables avoids the need for a 24-h urine collection and may be clinically useful.

METHODS

Variables of age, height, weight, sex, plasma creatinine, blood urea nitrogen (BUN), glucose, sodium, potassium, chloride, and carbon dioxide from a deidentified data set of 967 patients who had UCE measured were used to develop models to predict UCE. The model identified with the best predictive ability was validated and then retrospectively applied to a separate sample of 120 veterans who were critically ill to examine if UCE and CHI predicted malnutrition or were associated with outcomes.

RESULTS

A model was identified that included variables of plasma creatinine, BUN, age, and weight and was found to be highly correlated, moderately predictive of UCE, and statistically significant. Patients with model-estimated CHI  ≤  60% had significantly lower body weight, body mass index, plasma creatinine, and sera albumin and prealbumin levels; were 8.0 times more likely to be diagnosed with malnutrition; and were 2.6 times more likely to be readmitted in 6 months.

CONCLUSION

A model that predicts UCE offers a novel method to identify patients with low muscularity and malnutrition on admission without the use of invasive tests.

A focus on leucine in the nutritional regulation of human skeletal muscle metabolism in ageing, exercise and unloading states

Muscle protein synthesis (MPS) and muscle protein breakdown (MPB) are influenced through dietary protein intake and physical (in)activity, which it follows, regulate skeletal muscle (SKM) mass across the lifespan. Following consumption of dietary protein, the bio-availability of essential amino acids (EAA), and primarily leucine (LEU), drive a transient increase in MPS with an ensuing refractory period before the next MPS stimulation is possible (due to the "muscle full" state). At the same time, MPB is periodically constrained via reflex insulin actions. Layering exercise on top of protein intake increases the sensitivity of SKM to EAA, therefore extending the muscle full set-point (∼48 h), to permit long-term remodelling (e.g., hypertrophy). In contrast, ageing and physical inactivity are associated with a premature muscle full set-point in response to dietary protein/EAA and contractile activity. Of all the EAA, LEU is the most potent stimulator of the mechanistic target of rapamycin complex 1 (mTORC1)-signalling pathway, with the phosphorylation of mTORC1 substrates increasing ∼3-fold more than with all other EAA. Furthermore, maximal MPS stimulation is also achieved following low doses of LEU-enriched protein/EAA, negating the need for larger protein doses. As a result, LEU supplementation has been of long term interest to maximise muscle anabolism and subsequent net protein accretion, especially when in tandem with resistance exercise. This review highlights current knowledge vis-à-vis the anabolic effects of LEU supplementation in isolation, and in enriched protein/EAA sources (i.e., EAA and/or protein sources with added LEU), in the context of ageing, exercise and unloading states.

Neuromuscular defects after infection with a beta coronavirus in mice

COVID-19 affects primarily the lung. However, several other systemic alterations, including muscle weakness, fatigue and myalgia have been reported and may contribute to the disease outcome. We hypothesize that changes in the neuromuscular system may contribute to the latter symptoms observed in COVID-19 patients. Here, we showed that C57BL/6J mice inoculated intranasally with the murine betacoronavirus hepatitis coronavirus 3 (MHV-3), a model for studying COVID-19 in BSL-2 conditions that emulates severe COVID-19, developed robust motor alterations in muscle strength and locomotor activity. The latter changes were accompanied by degeneration and loss of motoneurons that were associated with the presence of virus-like particles inside the motoneuron. At the neuromuscular junction level, there were signs of atrophy and fragmentation in synaptic elements of MHV-3-infected mice. Furthermore, there was muscle atrophy and fiber type switch with alteration in myokines levels in muscles of MHV-3-infected mice. Collectively, our results show that acute infection with a betacoronavirus leads to robust motor impairment accompanied by neuromuscular system alteration.

Multidisciplinary approach to sarcopenia: a narrative review

Sarcopenia is a condition in which muscle mass and strength are decreased and muscle function is impaired. It is an indicator of frailty and loss of independence in older adults. It is also associated with increased physical disability, which increases the risk of falls. As a multifactorial disease, sarcopenia is caused by a combination of factors including aging, hormonal changes, nutritional deficiencies, and physical inactivity. Understanding the underlying pathophysiology of sarcopenia and identifying its different causes is critical to developing effective prevention and treatment strategies. This review summarizes the pathophysiology, consequences, diagnostic methods, and multidisciplinary approaches to sarcopenia.

Chronic high-intensity interval training and moderate-intensity continuous training are both effective in increasing maximum fat oxidation during exercise in overweight and obese adults: A meta-analysis

Objective

to (1) systematically review the chronic effect of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on maximal fat oxidation (MFO) in overweight and obese adults, and (2) explore MFO influencing factors and its dose-response relationships with HIIT and MICT.

Methods

Studies using a between-group design involving overweight and obese adults and assessing the effect of HIIT and MICT on MFO were included. A meta-analysis on MFO indices was conducted, and the observed heterogeneities were explored through subgroup, regression, and sensitivity analyses.

Results

Thirteen studies of moderate to high quality with a total of 519 overweight and obese subjects were included in this meta-analysis (HIIT, n = 136; MICT, n = 235; Control, n = 148). HIIT displayed a statistically significant favorable effect on MFO compared to no-training (MD = 0.07; 95%CI [0.03 to 0.11]; I2 = 0%). Likewise, MICT displayed a statistically significant favorable effect on MFO compared to no-training (MD = 0.10; 95%CI [0.06 to 0.15]; I2 = 95%). Subgroup and regression analyses revealed that exercise intensity (Fatmax vs. non-Fatmax; %VO2peak), exercise mode, BMI, and VO2peak all significantly moderated MICT on MFO. When analyzing studies that have directly compared HIIT and MCIT in obese people, it seems there is no difference in the MFO change (MD = 0.01; 95%CI [-0.02 to 0.04]; I2 = 64%). No publication bias was found in any of the above meta-analyses (Egger's test p > 0.05 for all).

Conclusion

Both HIIT and MICT are effective in improving MFO in overweight and obese adults, and they have similar effects. MCIT with an intensity of 65-70% VO2peak, performed 3 times per week for 60 min per session, will optimize MFO increases in overweight and obese adults. Given the lack of studies examining the effect of HIIT on MFO in overweight and obese adults and the great diversity in the training protocols in the existing studies, we were unable to make sound recommendations for training.

Prolonged mechanical muscle loading increases mechanosensor gene and protein levels and causes a moderate fast-to-slow fiber type switch in mice

Mechanosensing and subsequent mechanotransduction are indispensable for muscle plasticity. Nevertheless, a scarcity of literature exists regarding an all-encompassing understanding of the muscle mechanosensing machinery's response to prolonged loading, especially in conditions that resemble a natural physiological state of skeletal muscle. This study aimed to comprehensively explore the effects of prolonged mechanical loading on mechanosensitive components, skeletal muscle characteristics, and metabolism-related gene clusters. Twenty male C57BL/6J mice were randomly divided into two groups: control and prolonged mechanical loading. To induce prolonged mechanical loading on the triceps brachii (TRI) and biceps brachii (BIC) muscles, a 14-day period of tail suspension was implemented. In TRI only, prolonged mechanical loading caused a mild fast-to-slow fiber type shift together with increased mechanosensor gene and protein levels. It also increased transcription factors associated with slow muscle fibers while decreasing those related to fast-type muscle gene expression. Succinate dehydrogenase activity, a marker of muscle oxidative capacity, and genes involved in oxidative and mitochondrial turnover increased, whereas glycolytic-related genes decreased. Moreover, prolonged mechanical loading stimulated markers of muscle protein synthesis. Taken together, our data show a collective muscle-specific increase in mechanosensor gene and protein levels upon a period of prolonged mechanical loading in conditions that reflect a more natural physiological state of skeletal muscle in mice. We provide additional proof-of-concept that prolonged tail suspension-induced loading of the forelimbs triggers a muscle-specific fast-to-slow fiber type switch, and this coincides with increased protein synthesis-related signaling.NEW & NOTEWORTHY This study provides a comprehensive overview of the effects of prolonged loading on mechanosensitive components in conditions that better reflect the natural physiological state of skeletal muscle. Although the muscle mechanosensing machinery has been widely acknowledged for its responsiveness to altered loading, an inclusive understanding of its response to prolonged loading remains scarce. Our results show a fast-to-slow fiber type shift and an upregulation of mechanosensor gene and protein levels following prolonged loading.

The emerging role of Piezo1 channels in skeletal muscle physiology

Piezo1 channels are mechanically activated (MA) cation channels that are involved in sensing of various mechanical perturbations, such as membrane stretch and shear stress, and play a crucial role in cell mechanotransduction. In response to mechanical stimuli, these channels open up and allow cations to travel into the cell and induce biochemical reactions that can change the cell's metabolism and function. Skeletal muscle cells/fibers inherently depend upon mechanical cues in the form of fluid shear stress and contractions (physical exercise). For example, an exposure of skeletal muscles to chronic mechanical loading leads to increased anabolism and fiber hypertrophy, while prolonged mechanical unloading results in muscle atrophy. MA Piezo1 channels have recently emerged as key mechanosensors that are capable of linking mechanical signals and intramuscular signaling in skeletal muscle cells/fibers. This review will summarize the emerging role of Piezo1 channels in the development and regeneration of skeletal muscle tissue as well as in the regulation of skeletal muscle atrophy. In addition, an overview of potential Piezo1-related signaling pathways underlying anabolic and catabolic processes will be provided. A better understanding of Piezo1's role in skeletal muscle mechanotransduction may represent an important basis for the development of therapeutic strategies for maintaining muscle functions under disuse conditions and in some disease states.

Fat and lean mass predict time to hospital readmission or mortality in children treated for complicated severe acute malnutrition in Zimbabwe and Zambia

HIV and severe wasting are associated with post-discharge mortality and hospital readmission among children with complicated severe acute malnutrition (SAM); however, the reasons remain unclear. We assessed body composition at hospital discharge, stratified by HIV and oedema status, in a cohort of children with complicated SAM in three hospitals in Zambia and Zimbabwe. We measured skinfold thicknesses and bioelectrical impedance analysis (BIA) to investigate whether fat and lean mass were independent predictors of time to death or readmission. Cox proportional hazards models were used to estimate the association between death/readmission and discharge body composition. Mixed effects models were fitted to compare longitudinal changes in body composition over 1 year. At discharge, 284 and 546 children had complete BIA and skinfold measurements, respectively. Low discharge lean and peripheral fat mass were independently associated with death/hospital readmission. Each unit Z-score increase in impedance index and triceps skinfolds was associated with 48 % (adjusted hazard ratio 0·52, 95 % CI (0·30, 0·90)) and 17 % (adjusted hazard ratio 0·83, 95 % CI (0·71, 0·96)) lower hazard of death/readmission, respectively. HIV-positive v. HIV-negative children had lower gains in sum of skinfolds (mean difference -1·49, 95 % CI (-2·01, -0·97)) and impedance index Z-scores (-0·13, 95 % CI (-0·24, -0·01)) over 52 weeks. Children with non-oedematous v. oedematous SAM had lower mean changes in the sum of skinfolds (-1·47, 95 % CI (-1·97, -0·97)) and impedance index Z-scores (-0·23, 95 % CI (-0·36, -0·09)). Risk stratification to identify children at risk for mortality or readmission, and interventions to increase lean and peripheral fat mass, should be considered in the post-discharge care of these children.

Sit to stand test and handgrip strength in men and women with post-COVID-19 syndrome without invasive ventilator support: insights from a Brazilian observational study

Two valid tests have been used in patients with post-COVID-19 syndrome (coronavirus disease 2019) due to their fast application, feasibility, and accessible procedures, facilitating data collection in large groups: the 1-minute sit-to-stand test (STS) and handgrip strength (HGS) dynamometry. The present study aimed to: i) assess the STS and HGS in men and women with post-COVID-19 syndrome who did not require invasive ventilator support; ii) correlate STS repetitions and HGS with time since the COVID-19 diagnosis. Six hundred and twenty-two men and women with post-COVID-19 syndrome who did not require invasive ventilatory support performed the STS and HGS tests at the beginning of the rehabilitation process at a Reference Hospital Centre. Women over 55 years presented significantly lower results compared to participants under 55 years. For the HGS, the median ranged from 42 to 48 kg and 70 to 81 kg for the female and male groups, respectively. The correlations of time since COVID-19 diagnosis with STS and HGS ranged from -0.16 to 0.02 (p>0.05) for women and men, respectively.The test results could be used for the initial analysis of normality ranges and comparisons with other populations. Although STS repetitions and HGS presented low and non-significant correlations with time since the COVID-19 diagnosis, some COVID-19 sequelae were not measured, so these data should be interpreted with caution.

Effect of 1-year daily protein supplementation and physical exercise on muscle protein synthesis rate and muscle metabolome in healthy older Danes: a randomized controlled trial

BACKGROUND

The skeletal muscle mass decreases with age and the responsiveness of aging muscles' protein synthesis rate (MPS) to protein intake seems to deteriorate.

OBJECTIVE

This study investigated the impact of 12 months of protein supplementation with or without physical exercise training on the basal and postprandial MPS and the skeletal muscle metabolome of healthy older Danes (> 65 years, 29 females/37 males).

METHODS

Subjects were randomized to follow one of five intervention groups: (1) carbohydrate, (2) collagen protein, (3) whey protein, (4) home-based light resistance training with whey protein, and (5) center-based heavy-load resistance training with whey protein. Before and after the intervention, a tracer infusion trial was conducted to measure basal and postprandial MPS in response to intake of a cocktail consisting of 20 g whey hydrolysate + 10 g glucose. In addition, the skeletal muscle metabolome was measured using gas chromatography-mass spectrometry (GC-MS) at basal state and 4 h after the intake of the cocktail.

RESULTS

One year of daily protein or carbohydrate supplementation did not alter the basal and protein-stimulated postprandial muscle protein synthesis rate or the muscle metabolome of healthy older Danes. Basal MPS (%/h) at baseline for all subjects were 0.0034 ± 0,011 (mean ± SD). In contrast to previous studies, no difference was observed in basal MPS between males and females (p = 0.75). With the developed untargeted GC-MS methodology, it was possible to detect and tentatively annotate > 70 metabolites from the human skeletal muscle samples.

CONCLUSION

One year of protein supplementation in comparison to an isocaloric-control supplement seems to affect neither the MPS at basal or postprandial state nor the skeletal muscle metabolome.

CLINICAL TRIAL REGISTRY

Number: NCT02115698, clinicaltrials.gov/ct2/show/NCT02115698.

Associations among metabolic health, weight status, and various physical fitness components in Japanese adolescents: a cross-sectional study (NICE EVIDENCE study- Agano 3)

Aim was to examine associations among metabolic health, weight status, and various physical fitness (PF) components in 1744 Japanese adolescents aged 13-14. Anthropometric measurements and PF tests (20 m shuttle run test [20mSRT], handgrip strength/body mass [HG], standing long jump [SLJ], and sit ups [SU]) were administered. The bottom sex-specific quintile of PF indicated "low fit". Participants were classified as non-overweight (non-OW) or overweight/obese (OW) according to the International Obesity Task Force. Clustered metabolic risk was defined as the sum of Z scores for mean arterial pressure, non-high-density lipoprotein cholesterol, and HbA1c, divided by three, and ≥ 1 SD. Combination of weight status and scores for HG or SU were additively associated with clustered metabolic risk. Compared with the non-OW-moderate-high fit group, the OW-low HG group was 3.05 (95%CI: 1.88-4.97) times more likely to have clustered metabolic risk although risk was not significantly elevated in the OW-moderate-high HG group (1.52 [95%CI: 0.88-2.62]). A similar association was observed between OW and low SU scores but not between OW and low 20mSRT or SLJ scores. Adolescents with OW and moderate-high HG or SU scores had a lower prevalence of an unfavourable metabolic state than those with OW and low HG or SU results.

Identification of myokines susceptible to improve glucose homeostasis after bariatric surgery

IMPORTANCE AND OBJECTIVE

The identification of myokines susceptible to improve glucose homeostasis following bariatric surgery could lead to new therapeutic approaches for type 2 diabetes.

METHODS

Changes in the homeostasis model assessment (HOMA) test were assessed in patients before and 3 months after bariatric surgery. Changes in myokines expression and circulating levels were assessed using real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Myokines known to regulate glucose homeostasis were identified using literature (targeted study) and putative myokines using RNA-sequencing (untargeted study). A linear regression analysis adjusted for age and sex was used to search for associations between changes in the HOMA test and changes in myokines.

RESULTS

In the targeted study, brain-derived neurotrophic factor (BDNF) expression was upregulated (+30%, P = .006) while BDNF circulating levels were decreased (-12%, P = .001). Upregulated BDNF expression was associated with decreased HOMA of insulin resistance (HOMA-IR) (adjusted estimate [95% confidence interval {CI}]: -0.51 [-0.88 to -0.13], P = .010). Decreased BDNF serum levels were associated with decreased HOMA of beta-cell function (HOMA-B) (adjusted estimate [95% CI] = 0.002 [0.00002-0.0031], P = .046). In the untargeted study, upregulated putative myokines included XYLT1 (+64%, P < .001), LGR5 (+57, P< .001), and SPINK5 (+46%, P < .001). Upregulated LGR5 was associated with decreased HOMA-IR (adjusted estimate [95% CI] = -0.50 [-0.86 to -0.13], P = .009). Upregulated XYLT1 and SPINK5 were associated with increased HOMA of insulin sensitivity (HOMA-S) (respectively, adjusted estimate [95% CI] = 109.1 [28.5-189.8], P = .009 and 16.5 [0.87-32.19], P = .039).

CONCLUSIONS

Improved glucose homeostasis following bariatric surgery is associated with changes in myokines expression and circulating levels. In particular, upregulation of BDNF, XYLT1, SPINK5, and LGR5 is associated with improved insulin sensitivity. These results suggest that these myokines could contribute to improved glucose homeostasis following bariatric surgery.

STUDY REGISTRATION

NCT03341793 on ClinicalTrials.gov (https://clinicaltrials.gov/).