Lack of association between serum apelin levels and sarcopenia in elderly malnourished subjects.

OBJECTIVE: Sarcopenia is a condition characterized by muscle mass loss. Skeletal muscle is capable of producing and secreting different molecules called myokines, and apelin is one of them. The literature contains contradictory data on the relationship between apelin and sarcopenia. We decided to investigate the role of apelin in sarcopenia in subjects with disease-related malnutrition (DRM), a group of patients with a high rate of sarcopenia. PATIENTS AND METHODS: 83 elderly patients with DRM assessed according to the Global Leadership Initiative on Malnutrition (GLIM) criteria were included in the study, with a mean age of 69.9±3.8 years. Anthropometric data, muscle mass by ultrasound at the rectus femoris quadriceps (RFQ) level, bioimpedance [skeletal muscle mass (SMM), appendicular SMM (aSMM) and aSMM index (aSMMI)], dynamometry, biochemical parameters, dietary intake, circulating apelin levels were determined in all patients. RESULTS: a total of 33 patients (37.9%) were diagnosed with sarcopenia, while 54 patients did not present sarcopenia (60.1%). Body weight (-5.5±2.0 kg, p=0.01), calf circumference (-1.9±0.2 cm, p=0.02), phase angle (-0.6±0.2º, p=0.01), reactance (-6.8±2.3 Ohms, p=0.03), resistance (-38.8±12.3 Ohms, p=0.04), SMM (-2.2±0.3 kg, p=0.04), aSMM (-2.2±0.2 kg, p=0.03) and aSMMI (-0.6±0.2 kg, p=0.02), dominant muscle area (-0.6±0.2 cm2, p=0.04), dominant Y axis (-0.4±0.1 cm, p=0.03), dominant X/Y axis (1.1±0.3 cm, p=0.04), strength (-5.1±1.3 kg, p=0.01), albumin (-0.9±0.1 g/dl, p=0.02) and prealbumin (-4.6±0.7 mg/dl, p=0.02) were worse in patients with sarcopenia than non-sarcopenic patients. Circulating apelin levels were similar in both groups. No significant correlation of apelin levels was detected, either with bioimpedance data or with muscle ultrasonography data. The multivariant analysis did not detect a significant association of apelin with the presence of sarcopenia. CONCLUSIONS: Our study shows a lack of association between apelin and sarcopenia in elderly malnourished patients.

A Preclinical Model of Sepsis-Induced Myopathy with Disuse in Mice.

Sepsis is a major cause of in-hospital deaths. Improvements in treatment result in a greater number of sepsis survivors. Approximately 75% of the survivors develop muscle weakness and atrophy, increasing the incidence of hospital readmissions and mortality. However, the available preclinical models of sepsis do not address skeletal muscle disuse, a key component for the development of sepsis-induced myopathy. Our objective in this protocol is to provide a step-by-step guideline for a mouse model that reproduces the clinical setting experienced by a bedridden septic patient. Male C57Bl/6 mice were used to develop this model. Mice underwent cecal ligation and puncture (CLP) to induce sepsis. Four days post-CLP, mice were subjected to hindlimb suspension (HLS) for seven days. Results were compared with sham-matched surgeries and/or animals with normal ambulation (NA). Muscles were dissected for in vitro muscle mechanics and morphological assessments. The model results in marked muscle atrophy and weakness, a similar phenotype observed in septic patients. The model represents a platform for testing potential therapeutic strategies for the mitigation of sepsis-induced myopathy.

CT-determined low skeletal muscle index predicts poor prognosis in patients with colorectal cancer.

BACKGROUND: Sarcopenia is highly prevalent among patients with colorectal cancer (CRC). Computed tomography (CT)-based assessment of low skeletal muscle index (SMI) is widely used for diagnosing sarcopenia. However, there are conflicting findings on the association between low SMI and overall survival (OS) in CRC patients. The objective of this study was to investigate whether CT-determined low SMI can serve as a valuable prognostic factor in CRC. METHODS: We collected data from patients with CRC who underwent radical surgery at our institution between June 2020 and November 2021. The SMI at the third lumbar vertebra was calculated using CT scans, and the cutoff values for defining low SMI were determined using receiver operating characteristic curves. Univariate and multivariate analyses were performed to assess the associations between clinical characteristics and postoperative major complications. RESULTS: A total of 464 patients were included in the study, 229 patients (46.7%) were classified as having low SMI. Patients with low SMI were older and had a lower body mass index (BMI), a higher neutrophil to lymphocyte ratio (NLR), and higher nutritional risk screening 2002 (NRS2002) scores compared to those with normal SMI. Furthermore, patients with sarcopenia had a higher rate of major complications (10.9% vs. 1.3%; p < 0.001) and longer length of stay (9.09 ± 4.86 days vs. 8.25 ± 3.12 days; p = 0.03). Low SMI and coronary heart disease were identified as independent risk factors for postoperative major complications. Moreover, CRC patients with low SMI had significantly worse OS. Furthermore, the combination of low SMI with older age or TNM stage II + III resulted in the worst OS in each subgroup analysis. CONCLUSIONS: CT-determined low SMI is associated with poor prognosis in patients with CRC, especially when combined with older age or advanced TNM stage.

Lactate transported by MCT1 plays an active role in promoting mitochondrial biogenesis and enhancing TCA flux in skeletal muscle.

Once considered as a "metabolic waste," lactate is now recognized as a major fuel for tricarboxylic acid (TCA) cycle. Our metabolic flux analysis reveals that skeletal muscle mainly uses lactate to fuel TCA cycle. Lactate is transported through the cell membrane via monocarboxylate transporters (MCTs) in which MCT1 is highly expressed in the muscle. We analyzed how MCT1 affects muscle functions using mice with specific deletion of MCT1 in skeletal muscle. MCT1 deletion enhances running performance, increases oxidative fibers while decreasing glycolytic fibers, and enhances flux of glucose to TCA cycle. MCT1 deficiency increases the expression of mitochondrial proteins, augments cell respiration rate, and elevates mitochondrial activity in the muscle. Mechanistically, the protein level of PGC-1α, a master regulator of mitochondrial biogenesis, is elevated upon loss of MCT1 via increases in cellular NAD+ level and SIRT1 activity. Collectively, these results demonstrate that MCT1-mediated lactate shuttle plays a key role in regulating muscle functions by modulating mitochondrial biogenesis and TCA flux.

Continuous blood flow restriction during repeated-sprint exercise increases peripheral but not systemic physiological and perceptual demands.

This study examined the impact of continuous blood flow restriction (BFR) during repeated-sprint exercise (RSE) on acute performance, peripheral, systemic physiological, and perceptual responses. In a randomized crossover design, 26 adult male semi-professional and amateur team-sport players completed two RSE sessions (3 sets of 5 × 5-s sprints with 25 s of passive recovery and 3 min of rest) with continuous BFR (45% arterial occlusion; excluding during between-set rest periods) or without (non-BFR). Mean and peak power output were significantly lower (p < 0.001) during BFR compared to non-BFR (dz = 0.85 and 0.77, respectively). Minimum tissue saturation index during the sprints and rest periods was significantly reduced (p < 0.001) for BFR (dz = 1.26 and 1.21, respectively). Electromyography root mean square was significantly decreased (p < 0.01) for biceps femoris and lateral gastrocnemius muscles during BFR (dz = 0.35 and 0.79, respectively), but remained unchanged for the vastus lateralis muscle in both conditions. Oxygen consumption and minute ventilation were significantly reduced (both p < 0.01) for BFR (dz = 1.46 and 0.43, respectively). Perceived limb discomfort was significantly higher (p < 0.001) for BFR (dz = 0.78). No differences (p > 0.05) in blood lactate concentration or rating of perceived exertion were observed between conditions. Blood flow-restricted RSE reduced performance and likely increased the physiological and perceptual stimulus for the periphery with greater reliance on anaerobic glycolysis, despite comparable or decreased systemic demands.

Full-body resistance training promotes greater fat mass loss than a split-body routine in well-trained males: A randomized trial.

While significant progress has been made in understanding the resistance training (RT) strategy for muscle hypertrophy increase, there remains limited knowledge about its impact on fat mass loss. This study aimed to investigate whether full-body is superior to split-body routine in promoting fat mass loss among well-trained males. Twenty-three participants were randomly assigned to 1 of 2 groups: full-body (n = 11, training muscle groups 5 days per week) and split-body (n = 12, training muscle groups 1 day per week). Both groups performed a weekly set volume-matched condition (75 sets/week, 8-12 repetition maximum at 70%-80 % of 1RM) for 8 weeks, 5 days per week with differences only in the routine. Whole-body and regional fat were assessed using DXA at the beginning and at the end of the study. Full-body RT elicited greater losses compared to split-body in whole-body fat mass (-0.775 ± 1.120 kg vs. +0.317 ± 1.260 kg; p = 0.040), upper-limb fat mass (-0.085 ± 0.118 kg vs. +0.066 ± 0.162 kg; p = 0.019), gynoid fat mass (-0.142 ± 0.230 kg vs. +0.123 ± 0.230 kg; p = 0.012), lower-limb fat mass (-0.197 ± 0.204 kg vs. +0.055 ± 0.328 kg; p = 0.040), and a trend in interaction in android fat mass (-0.116 ± 0.153 kg vs. +0.026 ± 0.174 kg; p = 0.051), with large effects sizes (η2 p ≥ 0.17). This study provides evidence that full-body is more effective in reducing whole-body and regional fat mass compared to split-body routine in well-trained males.

Blood flow restriction Exercise in the perioperative setting to Prevent loss of muscle mass in patients with pancreatic, biliary tract, and liver cancer: study protocol for the PREV-Ex randomized controlled trial.

BACKGROUND: Patients diagnosed with pancreatic, biliary tract, and liver cancer often suffer from a progressive loss of muscle mass. Given the considerable functional impairments in these patients, high musculoskeletal weight loads may not be well tolerated by all individuals. The use of blood-flow restricted resistance training (BFR-T) which only requires low training loads may allow for a faster recovery of muscle due to avoidance of high levels of mechanical muscle stress associated with high-load resistance exercise. This study aims to investigate whether BFR-T can prevent or slow down the loss of skeletal muscle mass and enhance the functional capacity and mental health of patients with pancreatic, biliary tract, and liver cancer. METHODS: The PREV-Ex exercise trial is a multicenter two-armed randomized controlled trial. Patients will be randomized to an exercise program consisting of home-based low-load BFR-T during a combined pre- and postoperative period for a total of 6-10 weeks (prehabilitation and rehabilitation), or to a control group. Protein supplementation will be given to both groups to ensure adequate protein intake. The primary outcomes, skeletal muscle thickness and muscle cross-sectional area, will be assessed by ultrasound. Secondary outcomes include the following: (i) muscle catabolism-related and inflammatory bio-markers (molecular characteristics will be assessed from a vastus lateralis biopsy and blood samples will be obtained from a sub-sample of patients); (ii) patient-reported outcome measures (self-reported fatigue, health-related quality of life, and nutritional status will be assessed through validated questionnaires); (iii) physical fitness/performance/activity (validated tests will be used to evaluate physical function, cardiorespiratory fitness and maximal isometric muscle strength. Physical activity and sedentary behavior (assessed using an activity monitor); (iv) clinical outcomes: hospitalization rates and blood status will be recorded from the patients' medical records; (v) explorative outcomes of patients' experience of the exercise program which will be evaluated using focus group/individual interviews. DISCUSSION: It is worthwhile to investigate new strategies that have the potential to counteract the deterioration of skeletal muscle mass, muscle function, strength, and physical function, all of which have debilitating consequences for patients with pancreatic, biliary tract, and liver cancer. The expected findings could improve prognosis, help patients stay independent for longer, and possibly reduce treatment-related costs. TRIAL REGISTRATION: ClinicalTrials.gov NCT05044065. Registered on September 14, 2021.

STAT3 inhibition recovers regeneration of aged muscles by restoring autophagy in muscle stem cells.

Age-related reduction in muscle stem cell (MuSC) regenerative capacity is associated with cell-autonomous and non-cell-autonomous changes caused by alterations in systemic and skeletal muscle environments, ultimately leading to a decline in MuSC number and function. Previous studies demonstrated that STAT3 plays a key role in driving MuSC expansion and differentiation after injury-activated regeneration, by regulating autophagy in activated MuSCs. However, autophagy gradually declines in MuSCs during lifespan and contributes to the impairment of MuSC-mediated regeneration of aged muscles. Here, we show that STAT3 inhibition restores the autophagic process in aged MuSCs, thereby recovering MuSC ability to promote muscle regeneration in geriatric mice. We show that STAT3 inhibition could activate autophagy at the nuclear level, by promoting transcription of autophagy-related genes, and at the cytoplasmic level, by targeting STAT3/PKR phosphorylation of eIF2α. These results point to STAT3 inhibition as a potential intervention to reverse the age-related autophagic block that impairs MuSC ability to regenerate aged muscles. They also reveal that STAT3 regulates MuSC function by both transcription-dependent and transcription-independent regulation of autophagy.

Relationship between muscle and subcutaneous adipose tissue size and density and proximal femur bone in elderly women with hip fracture.

BACKGROUND: Both osteoporosis and sarcopenia are associated with aging, increasing the likelihood of falls in older adults and consequently raising the risk of hip fractures (HF). AIMS: To explore the relationship between the size and density of muscle and subcutaneous adipose tissue (SAT) and the bone mineral density (BMD) of the proximal femur in elderly women with HF. METHODS: Quantitative computed tomography (QCT) was conducted on the hips of 661 female participants who experienced low-energy acute HFs to measure both areal BMD (aBMD) and volume BMD (vBMD). Measurements were taken for the cross-sectional area (CSA) and density of the muscle around the hip and adjacent SAT. Multivariable linear regression models were applied to assess the relationship between these parameters. RESULTS: Most increases in the density of the gluteus medius and minimus muscle (G.Med/MinM) were correlated with higher BMD in the femoral neck fracture (FNF) group with osteoporosis. In the FNF group, gluteus maximus muscle (G.MaxM) density was negatively associated with the BMD parameters of the proximal femur in individuals with osteoporosis, while they were positively associated with nonosteoporosis. In the intertrochanteric fracture (ITF) group without osteoporosis, both FN aBMD and FN vBMD showed significant correlations with G.Med/MinM density. DISCUSSION: In women with HFs, bone and muscle are closely related. CONCLUSIONS: In older women with HFs, density but not CSA of the G.Med/MinM were associated with BMD parameters of the proximal femur. Osteoporosis may influence the relationship between G.MaxM density and proximal femur BMD in elderly women with FNF.

Whole-genome SNP allele frequency differences between Tibetan and Large white pigs reveal genes associated with skeletal muscle growth.

BACKGROUND: The skeletal muscle growth rate and body size of Tibetan pigs (TIB) are lower than Large white pigs (LW). However, the underlying genetic basis attributing to these differences remains uncertain. To address this knowledge gap, the present study employed whole-genome sequencing of TIB (slow growth) and LW (fast growth) individuals, and integrated with existing NCBI sequencing datasets of TIB and LW individuals, enabling the identification of a comprehensive set of genetic variations for each breed. The specific and predominant SNPs in the TIB and LW populations were detected by using a cutoff value of 0.50 for SNP allele frequency and absolute allele frequency differences (△AF) between the TIB and LW populations. RESULTS: A total of 21,767,938 SNPs were retrieved from 44 TIB and 29 LW genomes. The analysis detected 2,893,106 (13.29%) and 813,310 (3.74%) specific and predominant SNPs in the TIB and LW populations, and annotated to 24,560 genes. Further GO analysis revealed 291 genes involved in biological processes related to striated and/or skeletal muscle differentiation, proliferation, hypertrophy, regulation of striated muscle cell differentiation and proliferation, and myoblast differentiation and fusion. These 291 genes included crucial regulators of muscle cell determination, proliferation, differentiation, and hypertrophy, such as members of the Myogenic regulatory factors (MRF) (MYOD, MYF5, MYOG, MYF6) and Myocyte enhancer factor 2 (MEF2) (MEF2A, MEF2C, MEF2D) families, as well as muscle growth inhibitors (MSTN, ACVR1, and SMAD1); KEGG pathway analysis revealed 106 and 20 genes were found in muscle growth related positive and negative regulatory signaling pathways. Notably, genes critical for protein synthesis, such as MTOR, IGF1, IGF1R, IRS1, INSR, and RPS6KA6, were implicated in these pathways. CONCLUSION: This study employed an effective methodology to rigorously identify the potential genes associated with skeletal muscle development. A substantial number of SNPs and genes that potentially play roles in the divergence observed in skeletal muscle growth between the TIB and LW breeds were identified. These findings offer valuable insights into the genetic underpinnings of skeletal muscle development and present opportunities for enhancing meat production through pig breeding.

Skin-inspired, sensory robots for electronic implants.

Drawing inspiration from cohesive integration of skeletal muscles and sensory skins in vertebrate animals, we present a design strategy of soft robots, primarily consisting of an electronic skin (e-skin) and an artificial muscle. These robots integrate multifunctional sensing and on-demand actuation into a biocompatible platform using an in-situ solution-based method. They feature biomimetic designs that enable adaptive motions and stress-free contact with tissues, supported by a battery-free wireless module for untethered operation. Demonstrations range from a robotic cuff for detecting blood pressure, to a robotic gripper for tracking bladder volume, an ingestible robot for pH sensing and on-site drug delivery, and a robotic patch for quantifying cardiac function and delivering electrotherapy, highlighting the application versatilities and potentials of the bio-inspired soft robots. Our designs establish a universal strategy with a broad range of sensing and responsive materials, to form integrated soft robots for medical technology and beyond.

Transcriptional response to an alternative diet on liver, muscle, and rumen of beef cattle.

Feed cost represents a major economic determinant within cattle production, amounting to an estimated 75% of the total variable costs. Consequently, comprehensive approaches such as optimizing feed utilization through alternative feed sources, alongside the selection of feed-efficient animals, are of great significance. Here, we investigate the effect of two diets, traditional corn-grain fed and alternative by-product based, on 14 phenotypes related to feed, methane emission and production efficiency and on multi-tissue transcriptomics data from liver, muscle, and rumen wall, derived from 52 Nellore bulls, 26 on each diet. To this end, diets were contrasted at the level of phenotype, gene expression, and gene-phenotype network connectivity. As regards the phenotypic level, at a P value < 0.05, significant differences were found in favour of the alternative diet for average daily weight gain at finishing, dry matter intake at finishing, methane emission, carcass yield and subcutaneous fat thickness at the rib-eye muscle area. In terms of the transcriptional level of the 14,776 genes expressed across the examined tissues, we found 487, 484, and 499 genes differentially expressed due to diet in liver, muscle, and rumen, respectively (P value < 0.01). To explore differentially connected phenotypes across both diet-based networks, we focused on the phenotypes with the largest change in average number of connections within diets and tissues, namely methane emission and carcass yield, highlighting, in particular, gene expression changes involving SREBF2, and revealing the largest differential connectivity in rumen and muscle, respectively. Similarly, from examination of differentially connected genes across diets, the top-ranked most differentially connected regulators within each tissue were MEOX1, PTTG1, and BASP1 in liver, muscle, and rumen, respectively. Changes in gene co-expression patterns suggest activation or suppression of specific biological processes and pathways in response to dietary interventions, consequently impacting the phenotype. The identification of genes that respond differently to diets and their associated phenotypic effects serves as a crucial stepping stone for further investigations, aiming to build upon our discoveries. Ultimately, such advancements hold the promise of improving animal welfare, productivity, and sustainability in livestock farming.

[Association between body composition and coronary artery calcification in patients with chronic kidney disease].

Objective: To investigate the association between body composition and coronary artery calcification in patients with chronic kidney disease (CKD). Methods: This cross-sectional study enrolled patients with CKD hospitalized from May 2019 to April 2022 at Sun Yat-sen Memorial Hospital, Guangzhou, China. Skeletal muscle mass index and visceral fat area were measured by bioelectrical impedance analysis. Coronary artery calcification was assessed by computed tomography. Patients were divided into coronary artery calcification group and non-coronary artery calcification group according to the incidence of coronary artery calcification. Patients were categorized into tertile groups according to their skeletal muscle mass index and visceral fat area levels ranging from the lowest to the highest levels (T1 to T3). We defined skeletal muscle mass index≤30.4% as low muscle mass and visceral fat area≥80.6 cm2 as high visceral fat based on the results of the restricted cubic spline graph. All individuals were divided into 4 phenotypes: normal body composition, low muscle mass, high visceral fat, and low muscle mass with high visceral fat. Spearman correlation analysis and logistic regression analysis were used to assess the association between skeletal muscle mass index, visceral fat area and coronary artery calcification. Results: A total of 107 patients with CKD were enrolled, with an age of (60.0±14.1) years, including 41 female patients (38.3%). Patients of coronary artery calcification group had lower skeletal muscle mass index ((32.0±4.8) vs. (34.3±4.8), P=0.016) and higher visceral fat area ((70.8±32.6) cm2 vs. (47.9±23.8) cm2, P<0.001) than those of non-coronary artery calcification group. Patients in the T3 group of skeletal muscle mass index had a lower prevalence of coronary artery calcification (17 (48.6%) vs. 28 (77.8%)) and a lower coronary artery calcification score (0.5 (0, 124.0) vs. 12.0 (0.3, 131.0)) than those in the T1 group (P<0.05). Similarly, patients in the T1 group of visceral fat area had a lower prevalence of coronary artery calcification (14 (40.0%) vs. 29 (80.6%)) and a lower coronary artery calcification score (0 (0, 3.0) vs. 37.0 (2.0, 131.0)) than those in the T3 group (P<0.05). Likewise, patients with both low muscle mass and low muscle mass with high visceral fat had a higher prevalence of coronary artery calcification (11(78.6%) vs. 33 (47.8%); 15 (83.3%) vs. 33 (47.8%)) and a higher coronary artery calcification score (31.1 (0.8, 175.8) vs. 0 (0, 16.4); 27.6 (6.4, 211.4) vs. 0 (0, 16.4)) than those with normal body composition (P<0.05). Spearman correlation analysis showed that skeletal muscle mass index was inversely correlated with coronary artery calcification score (r=-0.212, P=0.028), and visceral fat area was positively correlated with coronary artery calcification score (r=0.408, P<0.001). Multivariate logistic regression analysis showed that increased skeletal muscle mass index was inversely associated with coronary artery calcification prevalence (T2: OR=0.208, 95%CI: 0.056-0.770, P=0.019; T3: OR=0.195, 95%CI: 0.043-0.887, P=0.034), and reduced visceral fat area was inversely associated with coronary artery calcification prevalence (T1: OR=0.256, 95%CI: 0.071-0.923, P=0.037; T2: OR=0.263, 95%CI: 0.078-0.888, P=0.031). Consistently, both low muscle mass and low muscle mass with high visceral fat were associated with coronary artery calcification prevalence (OR=6.616, 95%CI: 1.383-31.656, P=0.018; OR=5.548, 95%CI: 1.062-28.973, P=0.042). Conclusion: Reduced skeletal muscle mass index and increased visceral fat area are significantly associated with both the prevalence and severity of coronary artery calcification in patients with CKD.

Neuromuscular Adaptations in Endurance-Trained Male Adolescents Versus Untrained Peers: A 9-Month Longitudinal Study.

BACKGROUND: Neuromuscular function is considered as a determinant factor of endurance performance during adulthood. However, whether endurance training triggers further neuromuscular adaptations exceeding those of growth and maturation alone over the rapid adolescent growth period is yet to be determined. OBJECTIVE: The present study investigated the concurrent role of growth, maturation, and endurance training on neuromuscular function through a 9-month training period in adolescent triathletes. METHODS: Thirty-eight 13- to 15-year-old males (23 triathletes [~6 h/week endurance training] and 15 untrained [<2 h/week endurance activity]) were evaluated before and after a 9-month triathlon training season. Maximal oxygen uptake (V̇O2max) and power at V̇O2max were assessed during incremental cycling. Knee extensor maximal voluntary isometric contraction torque (MVCISO) was measured and the voluntary activation level (VAL) was determined using the twitch interpolation technique. Knee extensor doublet peak torque (T100Hz) and normalized vastus lateralis (VL) electromyographic activity (EMG/M-wave) were also determined. VL and rectus femoris (RF) muscle architecture was assessed using ultrasonography. RESULTS: Absolute V̇O2max increased similarly in both groups but power at V̇O2max only significantly increased in triathletes (+13.8%). MVCISO (+14.4%), VL (+4.4%), and RF (+15.8%) muscle thicknesses and RF pennation angle (+22.1%) increased over the 9-month period in both groups similarly (p < 0.01), although no changes were observed in T100Hz, VAL, or VL EMG/M-wave. No changes were detected in any neuromuscular variables, except for coactivation. CONCLUSION: Endurance training did not induce detectible, additional neuromuscular adaptations. However, the training-specific cycling power improvement in triathletes may reflect continued skill enhancement over the training period.

Sex difference in skeletal muscle mass in relation to metabolic dysfunction-associated steatotic liver disease: a propensity score matching study.

BACKGROUND: While low muscle mass is considered a risk factor for metabolic dysfunction-associated steatotic liver disease (MASLD), whether the relationship is independent of fat mass remains unclear. OBJECTIVES: This study aims to clarify the association between the sex-specific height-adjusted low skeletal muscle mass index (LSMI) and MASLD. METHODS: Data from the 2008-2010 Korean National Health and Nutrition Examination Survey were analyzed. LSMI was defined using the 2019 Asian Working Group for Sarcopenia. The non-alcoholic fatty liver disease-liver fat score was used to assess MASLD. Gender-specific 1:1 propensity score matching (PSM) was performed to mitigate the confounding effects of anthropometric variables and lifestyles. Conditional logistic analysis was used on the dataset after PSM to estimate the odds ratio (OR) with a 95% confidence interval (CI). RESULTS: After PSM, the prevalence of MASLD was significantly higher in men with LSMI than in those without LSMI (37.4% vs. 29.6%). No significant difference was observed in the prevalence of MASLD between groups after PSM in women (20.4% vs. 20.3%). Conditional logistic analysis revealed that the odds of having MASLD were significantly higher in men with LSMI compared to those without LSMI (OR = 1.38, 95% CI: 1.09-1.75), while no significant association was found in women with LSMI (OR = 1.10, 95% CI: 0.87-1.40). CONCLUSION: Height-adjusted LSMI is an independent factor associated with MASLD in the condition of the same level of fat mass in men. Further prospective studies in diverse populations are needed to confirm our findings.

Acute versus non-acute targeted muscle reinnervation for pain control following major limb amputation: A comparative study.

BACKGROUND: Targeted muscle reinnervation (TMR) has been shown to reduce phantom limb pain (PLP) and residual limb pain (RLP) after major limb amputation. However, the effect of the timing of surgery on pain control and quality of life outcomes is controversial. We conducted a retrospective study to compare the outcomes of acute TMR for pain prevention with non-acute TMR for the treatment of established pain. METHODS: All patients treated with TMR in our institution between January 2018 and December 2021 were evaluated at 6, 12, 18 and 24 months post-operatively. Pain intensity and quality of life outcomes were assessed using the Brief Pain Inventory (Pain Severity and Pain Interference scales) and Pain Catastrophizing Scale. Outcomes were compared between acute and non-acute TMR using the Wilcoxon ranked-sum test or Fisher's exact test as appropriate. Multilevel mixed-effects linear regression was used to account for repeat measures and potential pain confounders. RESULTS: Thirty-two patients with 38 major limb amputations were included. Acute TMR patients reported significantly lower RLP and PLP scores, pain interference and pain catastrophisation at all time points (p < 0.05). Acute TMR was significantly associated with lower pain severity and pain interference in a linear mixed-effects model accounting for patient age, gender, amputation indication, amputation site, time post-TMR and repeated surveys (p < 0.05). There was no significant difference in the complication rate (p = 0.51). CONCLUSION: Acute TMR was associated with clinically and statistically significant pain outcomes that were better than that in non-acute TMR. This suggests that TMR should be performed with preventative intent, when possible, as part of a multidisciplinary approach to pain management, rather than deferred until the development of chronic pain.

Association of myosteatosis with short-term outcomes in patients with acute-on-chronic liver failure.

Sarcopenia (low muscle mass, i.e., quantity) is associated with poor clinical outcomes in patients with acute-on-chronic liver failure (ACLF). In this study, we aimed to illustrate the clinical prognostic value of myosteatosis (muscle fat infiltration) for short-term mortality in patients with ACLF. We retrospectively enrolled consecutive patients with ACLF between January 2019 and January 2022. Computed tomography-based body composition analysis was performed at the third lumbar vertebral level to determine skeletal muscle radiation attenuation. Fine and Gray's competing risk regression model, with liver transplantation as a competing risk, was used to assess the factors associated with 90-day mortality. A total of 431 patients with ACLF were included. Myosteatosis and sarcopenia were observed in 261 (60.6%) and 87 (20.2%) patients, respectively. Competitive risk regression showed that age (HR 1.021, 95% CI 1.000-1.043, P = 0.042), APASL ACLF Research Consortium (AARC) score (HR 1.498, 95% CI 1.312-1.710, P < 0.001), and sarcopenia (HR 1.802, 95% CI 1.062-3.060, P = 0.029) were independently associated with increased 90-day mortality. Subgroup analysis of male patients with HBV-ACLF revealed that myosteatosis (HR 2.119, 95% CI 1.101-4.078, P = 0.025) was promising prognostic factors for 90-day mortality after being adjusted for ascites, acute kidney injury, AARC score, and sarcopenia. Myosteatosis is predictive of short-term outcomes in male patients with HBV-ACLF. Our results emphasise the importance of focusing on muscle fat infiltration in patients with HBV-ACLF. Further studies are warranted to investigate the underlying mechanisms and potential therapies for myosteatosis.

Immediate Effect of Wearable Balance Training Device on Muscle Co-Contraction and Postural Control During Standing.

Postural control is one of the primary body functions for fall prevention. Unexpected perturbation-based balance training is effective for improving postural control. However, the effect of perturbation-based training using assistive devices on muscle activity and co-contraction for standing balance is still unclear. This training is also difficult to perform easily because it requires large instruments or expert guidance. The purpose of this study is to demonstrate the effect of perturbation-based balance training using a wearable balance training device (WBTD) on postural control. In this study, fourteen healthy young adult males were assigned to either a WBTD group or a sham group. In the intervention session, participants in the WBTD group were perturbed either left or right direction at random timing by the WBTD during tandem stance balance training. Participants in the Sham group did not receive external perturbation during tandem stance balance training. Before and after the intervention session, participants of both groups underwent unexpected lateral perturbation postural control testing (pre- and post-test). The normalized integral of electromyography (IEMG), co-contraction index (CCI), and center of pressure (COP) parameters were measured in the pre- and post-test. Experimental results showed that the WBTD group in the post-test significantly decreased left Gluteus Medius IEMG, CCI of both Gluteus Medius, and peak [Formula: see text] velocity, compared to those of the pre-test ( [Formula: see text], p =0.024 , p =0.031 , respectively). We conclude that balance training using WBTD could improve flexible postural control adjustment via cooperative muscle activation.

Effects of pilates exercises on strength, endurance and muscle power in older adults: Systematic review and meta-analysis.

INTRODUCTION: Pilates exercises have been used by the older adults and have shown potential to improve some components of physical fitness. OBJECTIVE: To verify the effects of Pilates on strength, endurance and muscle power in older adults. METHODS: The searches were performed in the databases: PubMed, EMBASE, CENTRAL, CINAHL, Web of Science, SPORTDiscus, LILACS and PEDro until September 2022, without filters that limited the date of publications or language. The studies included were: randomized clinical trials (RCTs); interventions that used Pilates; interventions with outcomes involving strength, endurance and/or muscle power; participants over 60 years old. RESULTS: 24 RCTs (1190 participants) were selected. There is low quality evidence that Pilates did not significantly improve muscle strength compared to the control group (Standardized Mean Difference (SMD) = 1.18 [95%CI -0.71, 3.08] I2 = 93%), and moderate quality compared to other exercises (SMD = 0.01 [CI95% -0.46, 0.48] I2 = 0%). Very low quality evidence shows that Pilates can improve muscular endurance of upper limbs compared to control group (Mean Difference (MD) = 4.87 [95%CI 2.38, 7.36] I2 = 88%) and lower limbs compared to other exercises (MD = 2.68 [CI95% 0.26, 5.10] I2 = 87%). It was not possible to perform muscle power analysis due to the reduced number of studies. CONCLUSION: Currently, it is not feasible to recommend Pilates exercises as a means to improve strength, endurance and muscle power in the older adults. More RCTs covering this topic are needed given the low quality of evidence available at this time.