Skeletal Muscle Quality Research Articles

Postabsorptive and postprandial myofibrillar protein synthesis rates at rest and after resistance exercise in women with postmenopause.

Feeding and resistance exercise stimulate myofibrillar protein synthesis (MPS) rates in healthy adults. This anabolic characterization of "healthy adults" has been namely focused on males. Therefore, the purpose of this study was to examine the temporal responses of MPS and anabolic signaling to resistance exercise alone or combined with the ingestion of protein in postmenopausal females and compare postabsorptive rates with young females. Sixteen females [60 ± 7 yr; body mass index (BMI) = 26 ± 12 kg·m-2] completed an acute bout of unilateral resistance exercise before consuming either: a fortified whey protein supplement (WHEY) or water. Participants received primed continuous infusions of L-[ring-13C6]phenylalanine with bilateral muscle biopsies before and after treatment ingestion at 2 h and 4 h in nonexercised and exercised legs. Resistance exercise transiently increased MPS above baseline at 0-2 h in the water condition (P = 0.007). Feeding after resistance exercise resulted in a late phase (2-4 h) increase in MPS in the WHEY condition (P = 0.005). In both conditions, resistance exercise did not enhance the cumulative (0-4 h) MPS response. In the nonexercised leg, MPS did not differ at 0-2 h, 2-4 h, or 0-4 h of the measurement periods (all, P > 0.05). Likewise, there were no changes in the phosphorylation of p70S6K, AMPKα, or total and phosphorylated yes-associated protein on Ser127. Finally, postabsorptive MPS was lower in premenopausal versus postmenopausal females (P = 0.023). Our results demonstrate that resistance exercise-induced changes in MPS are temporally regulated, but do not result in greater cumulative (0-4 h) MPS in postmenopausal women.NEW & NOTEWORTHY An adequate quality and quantity of skeletal muscle is relevant to support physical performance and metabolic health. Muscle protein synthesis (MPS) is an established remodeling marker, which can be hypertrophic or nonhypertrophic. Importantly, protein ingestion and resistance exercise are two strategies that support healthy muscle by stimulating MPS. Our study shows postmenopause modulates baseline MPS that may diminish the MPS response to the fundamental anabolic stimuli of protein ingestion and resistance exercise in older females.

Skeletal Muscle Evaluation in Patients With Acromegaly.

Patients with acromegaly are characterized by chronic exposure to high growth hormone (GH) and insulin-like growth factor-1 levels, known for their anabolic effect on skeletal muscle. Therefore, an increased skeletal muscle mass could be hypothesized in these individuals. Herein, we have performed a systematic revision of published evidence regarding skeletal muscle mass, quality, and performance in patients with acromegaly. A systematic review of the literature in the PubMed database up to September 1, 2023, was conducted with the following query: acromegaly AND ("muscle mass" OR "skeletal muscle"). We excluded studies that did not compare different disease states or used nonradiological methods for the skeletal muscle analyses, except for bioelectrical impedance analysis. Fifteen studies met the inclusion criteria. A total of 360 patients were evaluated for skeletal muscle mass, 122 for muscle fatty atrophy, and 192 for muscle performance. No clear evidence of increased skeletal muscle mass in patients with active disease compared to control or healthy individuals emerged. As for skeletal muscle quality, we observed a trend toward higher fatty infiltration among patients with acromegaly compared to healthy participants. Likewise, patients with active disease showed consistently worse physical performance compared to control or healthy individuals. Skeletal muscle in acromegaly has lower quality and performance compared to that of healthy individuals. The small number of published studies and multiple confounding factors (eg, use of different radiological techniques) contributed to mixed results, especially regarding skeletal muscle mass. Well-designed prospective studies are needed to investigate skeletal muscle mass in patients with acromegaly.

Skeletal muscle status and survival among patients with advanced biliary tract cancer

BackgroundStudies have demonstrated a prognostic role of sarcopenia (i.e., loss of skeletal muscle volume and functionality) in patients with various cancer types. In patients with biliary tract cancer, the quantity and quality of skeletal muscles and their serial changes have not been fully investigated in relation to survival outcomes.MethodsWe identified 386 patients with unresectable or recurrent biliary tract cancer and calculated skeletal muscle index (SMI) and skeletal muscle density (SMD) to estimate muscular quantity and quality, respectively, based on computed tomography images. Using the Cox regression model with adjustment for potential confounders, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for progression-free survival (PFS) and overall survival (OS) according to skeletal muscle status and its serial change.ResultsCompared to patients without sarcopenia, patients with sarcopenia were associated with shorter PFS (multivariable HR, 1.60; 95% CI, 1.15–2.22; P = 0.005), but not with OS (P = 0.027) at the adjusted α level of 0.013. SMD at baseline was associated with OS (multivariable HR comparing the extreme quartiles, 1.52; 95% CI, 1.07–2.14; Ptrend = 0.012), but not with PFS (Ptrend = 0.13). A reduction in SMI rather than that in SMD was associated with OS. Progressive disease was a risk factor for reductions in SMI and SMD.ConclusionsSkeletal muscle quantity and quality and their serial changes were associated with survival outcomes in patients with advanced biliary tract cancer. Our data highlight the importance of designing nutritional and physical interventions for improvements in skeletal muscle status.

Clinical Application of Skeletal Muscle Quantity and Quality Assessment Using Bioelectrical Impedance and Ultrasound Images.

A decline in muscle strength is a key factor responsible for physical dysfunction in older individuals. Both loss of muscle quantity and quality are associated with muscle strength decline. While the gold standard method for evaluating muscle mass and quality is magnetic resonance imaging, it is not suitable for clinical settings because of the measurement and analysis costs. Bioelectrical impedance analysis (BIA) and B-mode ultrasonography are clinically useful alternatives for skeletal muscle assessment owing to their feasibility and noninvasiveness. The recent advancements in the techniques for BIA and ultrasonography have improved their accuracy in assessing skeletal muscle quantity and quality, making them useful in detecting age-related and disease-specific alterations. This review comprehensively analyzes the advantages of using BIA and ultrasound imaging for assessing skeletal muscle quantity and quality and detecting muscle degeneration. We summarize the recent findings regarding age-related changes in muscle characteristics and the associations of muscle degeneration with physical dysfunction in patients with knee osteoarthritis. Furthermore, we discuss the clinical application of skeletal muscle assessment using BIA and ultrasound for evaluating training effects and exercise prescription.

The roles of sex hormones in the pathophysiology of age-related sarcopenia and frailty.

Sarcopenia is an age-related condition characterized by a progressive and systemic decline in skeletal muscle mass, quality, and strength. The incidence of sarcopenia contains sex-specific aspects, indicating the contribution of sex hormones to its pathophysiology. This review focuses on changing trends in sarcopenia, discusses alterations in definitions and diagnostic criteria, and emphasizes the association between sarcopenia and sex hormones. A literature search was performed on PubMed for related articles published between 1997 and December 2023 using appropriate keywords. Advances in research have emphasized the significance of muscle quality and strength over muscle mass, resulting in new diagnostic criteria for sarcopenia. Androgens demonstrated anabolic effects on skeletal muscles and played a significant role in the pathophysiology of sarcopenia. In clinical settings, androgen replacement therapy has exhibited certain positive outcomes for treating sarcopenia, despite concerns about potential side effects. Conversely, estrogen is involved in skeletal muscle maintenance, but the detailed mechanisms remain unclear. Moreover, results regarding the clinical application of estrogen replacement therapy for treating sarcopenia remained inconsistent. The elucidation of molecular mechanisms that involve sex hormones is eagerly awaited for novel therapeutic interventions for sarcopenia.

Prediction of gait independence by using the phase angle in postoperative patients with proximal femoral fractures: a retrospective study.

[Purpose] This study was aimed at investigating the relationship between skeletal muscle mass and muscle quality by using bioelectrical impedance analysis and ambulatory independence in patients with proximal femoral fractures. [Participants and Methods] The study included 120 patients admitted to a recovery rehabilitation unit for whom follow-up assessments were available. Skeletal muscle mass and phase angle were assessed using bioelectrical impedance analysis upon admission. The patients were divided into the following two groups based on their Functional Independence Measure gait score at discharge: gait-independent group (gait score: ≥6; n=74) and gait-dependent group (gait score: ≤5; n=46). [Results] The phase angle was associated with gait independence. The cut-off values for the phase angle predicting gait independence were 4° and 3.8° for male and female patients, respectively, a more accurate assessment compared with skeletal muscle mass analysis. [Conclusion] The phase angle was associated with gait independence in patients with proximal femoral fractures. The results of this study suggest that the evaluation of the phase angle is important for predicting gait independence in patients with proximal femoral fractures.

Meta-Analysis on the Association between Echo Intensity, Muscle Strength, and Physical Function in Older Individuals.

The use of ultrasonographic echo intensity (EI) to evaluate skeletal muscle quality and its effects on strength, explosive power, and physical function (PF) in older individuals remains unclear. This meta-analysis evaluated the associations among EI, muscle strength (MS), and PF in older individuals. We conducted a systematic search of the PubMed, Embase, Web of Science, SPORT Discus, and CINAHL databases through October 2022 to identify primary studies examining the association between EI and MS/PF. Effect sizes were computed using a random-effects model and presented using forest plots. Pearson correlation coefficient (r) and I2 statistics were used to measure heterogeneity. This meta-analysis included 24 patients. EI demonstrated a negative association with maximal strength (r=-0.351; 95% confidence interval [CI], -0.411 to -0.288; p<0.001) and explosive power (r=-0.342; 95% CI, -0.517 to -0.139; p=0.001) in older individuals. Handgrip strength also showed a significant negative correlation with EI (r=-0.361; 95% CI, -0.463 to -0.249; p<0.001). However, we observed only a small and non-significant negative association between EI and gait speed (r=-0.003; 95% CI, -0.083 to -0.077; p=0.943), and a weak non-significant correlation with the chair stand test (r=0.072; 95% CI, -0.045 to 0.187; p=0.227). Increased EI was associated with lower strength and power but not with gait speed or chair test performance in older individuals. Further large-sample studies with long-term follow-up are needed to improve frailty prediction and risk assessment in this population.

Computed tomography evaluation of skeletal muscle quality and quantity in people with morbid obesity with and without metabolic abnormality.

We investigated the differences in quantity and quality of skeletal muscle between metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) individuals using abdominal CT. One hundred and seventy-two people with morbid obesity who underwent bariatric surgery and 64 healthy control individuals participated in this retrospective study. We divided the people with morbid obesity into an MHO and MUO group. In addition, nonobese metabolic healthy people were included analysis to provide reference levels. CT evaluation of muscle quantity (at the level of the third lumbar vertebra [L3]) was performed by calculating muscle anatomical cross-sectional area (CSA), which was normalized to patient height to produce skeletal muscle index (SMI). Muscle quality was assessed as skeletal muscle density (SMD), which was calculated from CT muscle attenuation. To characterize intramuscular composition, muscle attenuation was classified into three categories using Hounsfield unit (HU) thresholds: -190 HU to -30 HU for intermuscular adipose tissue (IMAT), -29 to +29 HU for low attenuation muscle (LAM), and +30 to +150 HU for normal attenuation muscle (NAM). People with morbid obesity comprised 24 (14%) MHO individuals and 148 (86%) MUO individuals. The mean age of the participants was 39.7 ± 12.5 years, and 154 (65%) participants were women. MUO individuals had a significantly greater total skeletal muscle CSA than MHO individuals in the model that adjusted for all variables. Total skeletal muscle SMI, SMD, NAM index, LAM index, and IMAT index did not differ between MHO and MUO individuals for all adjusted models. Total skeletal muscle at the L3 level was not different in muscle quantity, quality, or intramuscular composition between the MHO and MUO individuals, based on CT evaluation. MHO individuals who are considered "healthy" should be carefully monitored and can have a similar risk of metabolic complications as MUO individuals, at least based on an assessment of skeletal muscle.

Association of skeletal muscle function, quantity, and quality with gut microbiota in Japanese adults: A cross-sectional study.

The gut microbiota has emerged as a new intervention target for sarcopenia. Prior studies in humans have focused on the association between gut microbiota and skeletal muscle quantity, while the evidence on muscle function and quality is lacking. This study aimed to identify gut microbiota genera associated with skeletal muscle function, quantity, and quality in a general population of Japanese adults. This cross-sectional study included 164 participants aged 35-80 years, women and men recruited from urban areas of Japan. Fecal samples were collected and analyzed using 16S rRNA gene amplicon sequencing. Skeletal muscle function was measured using handgrip strength and leg extension power (LEP), while skeletal muscle mass was estimated using bioelectrical impedance analysis. Phase angle was used as a measure of skeletal muscle quality. Multivariate linear regression analysis stratified by age group was used to examine the association between the dominant genera of the gut microbiota and skeletal muscle variables. A significant association was found between Bacteroides and Prevotella 9 with LEP only in the ≥60 years group. When both Bacteroides and Prevotella 9 were included in the same regression model, only Bacteroides remained consistently and significantly associated with LEP. No significant associations were observed between skeletal muscle mass, handgrip strength, and phase angle and major gut microbiota genera. In this study, we observed a significant positive association between Bacteroides and leg muscle function in older adults. Further studies are required to elucidate the underlying mechanisms linking Bacteroides to lower-extremity muscle function. Geriatr Gerontol Int 2024; 24: 53-60.

Skeletal muscle-specific inducible AMPKα1/α2 knockout mice develop muscle weakness, glycogen depletion, and fibrosis that persists during disuse atrophy.

The 5' adenosine monophosphate-activated protein kinase (AMPK) is an important skeletal muscle regulator implicated as a possible therapeutic target to ameliorate the local undesired deconditioning of disuse atrophy. However, the muscle-specific role of AMPK in regulating muscle function, fibrosis, and transcriptional reprogramming during physical disuse is unknown. The purpose of this study was to determine how the absence of both catalytic subunits of AMPK in skeletal muscle influences muscle force production, collagen deposition, and the transcriptional landscape. We generated skeletal muscle-specific tamoxifen-inducible AMPKα1/α2 knockout (AMPKα-/-) mice that underwent 14 days of hindlimb unloading (HU) or remained ambulatory for 14 days (AMB). We found that AMPKα-/- during ambulatory conditions altered body weight and myofiber size, decreased muscle function, depleted glycogen stores and TBC1 domain family member 1 (TBC1D1) phosphorylation, increased collagen deposition, and altered transcriptional pathways. Primarily, pathways related to cellular senescence and mitochondrial biogenesis and function were influenced by the absence of AMPKα. The effects of AMPKα-/- persisted, but were not worsened, following hindlimb unloading. Together, we report that AMPKα is necessary to maintain skeletal muscle quality.NEW & NOTEWORTHY We determined that skeletal muscle-specific AMPKα knockout (KO) mice display functional, fibrotic, and transcriptional alterations before and during muscle disuse atrophy. We also observed that AMPKα KO drives muscle fibrosis and pathways related to cellular senescence that continues during the hindlimb unloading period.

Effect of Pre-Transplantation Nutritional Status on the Early Related Complications of Allogeneic Hematopoietic Stem Cell Transplantation:a Cohort Study

Background Allogeneic hematopoietic stem cell transplantation is an effective method for the treatment of hematologic malignancies. Malnutrition is a common complication and has a negative impact on poor prognosis. It has been proved that blood biochemical indexes such as muscle mass ratio albumin etc. can reflect earlier the nutritional status of patients, but the influence of muscle mass pre-transplantation on the early transplantation related complications remains unclear. Objective To investigate the effect of pre-transplantation skeletal muscle mass (SMM) on the early outcome of allogeneic hematopoietic stem cell transplantation, and to provide clinical evidence for nutritional intervention and prognosis improvement. Method A cohort study was conducted in 77 patients with leukemia who received allogeneic hematopoietic stem cell transplantation in the Hematology Medical Center of Chongqing Xinqiao Hospital from January to October 2022 were selected. The skeletal muscle quality was evaluated by bioelectrical impedance method. According to the skeletal muscle mass, the patients were divided into normal skeletal muscle mass group(36) and low skeletal muscle mass group(41). The baseline data of the patients were collected, including personal information and clinical data. SPSS23.0 software was used to compare the differences in oral mucositis, digestive tract symptoms, infection and hematopoietic reconstitution time between the two groups. Result Before transplantation, the SMM of patients was poor, which was not up to the normal value in 53.25%.The incidence of oral mucitis in normal SMM group was 41.67%, significantly lower than that in low SMM group 92.68%( χ2=23.255, P<0.001).The severity of oral mucositis was significantly different (Z=6.461, P<0.001) between the normal SMM group and the low SMM group. The incidence of hypoalbuminemia in normal SMM group was 16.67%, significantly lower than that in low SMM group 46.34%( χ2=7.699， P<0.001).The incidence of overt gastrointestinal bleeding and infection in normal SMM group were significantly lower than those in low SMM group ( c ２=4.208， P=0.040； c ２=4.727， P=0.030). the neutrophils and platelets grafting time in the normal SMM group was significantly shorter than that in the low SMM group ( Z=2.943， P=0.003； Z=2.756， P=0.006). There was no significant difference in the incidence of diarrhea, nausea and vomiting, stomachache/ abdominal pain between the two groups. Conclusion The incidence of low skeletal muscle mass is high in patients before transplantation, and low skeletal muscle mass is associated with the onset of oral mucositis, the severity of oral mucositis, hypoalbuminemia,gastrointestinal bleeding ,infectionand the delay of neutrophil and platelet implantation time in patients at the early stage of transplantation. Patients should actively improve skeletal muscle mass before transplantation to improve the early outcome of transplantation.

Relation of leg phase angle from bioelectrical impedance analysis with voluntary and evoked contractile properties of the plantar flexors

Introduction: Bioelectrical impedance analysis (BIA) can noninvasively and quickly assess electrical properties of the body, such as the phase angle. Phase angle is regarded as the quantity and/or quality of skeletal muscle and is associated with exercise performance, such as jump height and walking speed. Although the phase angle derived from BIA is assumed to be a useful way to assess muscle function, the relationship between the phase angle and neuromuscular properties has not been fully investigated. The purpose of this study was to investigate the association of phase angle with voluntary and evoked contractile properties in 60 adults (age, 21–83 years; 30 females and 30 males).Methods: The phase angle of the right leg at 50 kHz was evaluated using BIA. The twitch contractile properties (peak twitch torque [PTtwitch], rate of twitch torque development [RTDtwitch], and time-to-PTtwitch [TPTtwitch]) of the plantar flexors were measured using tibial nerve electrical stimulation. Maximal voluntary isometric contractions (MVICs) were performed to measure the maximal muscle strength and explosive muscle strength, from which the peak MVIC torque (PTMVIC) and rate of torque development (RTD) over a time interval of 0–200 ms were assessed, respectively. The root mean square (RMS) values of electromyographic (EMG) activity during the PTMVIC and RTD measurements (EMG-RMSMVIC and EMG-RMSRTD, respectively) were calculated. The RTD and EMG-RMSRTD were normalized using PTMVIC and EMG-RMSMVIC, respectively.Results and discussion: Phase angle significantly correlated with twitch contractile properties (|r| ≥ 0.444, p < 0.001), PTMVIC (r = 0.532, p < 0.001), and RTD (r = 0.514, p < 0.001), but not with normalized RTD (r = 0.242, p = 0.065) or normalized EMG-RMSRTD (r = −0.055, p = 0.676). When comparing measurement variables between the low- and high-phase angle groups while controlling for sex and age effects, the high-phase angle group showed greater PTtwitch, RTDtwitch, PTMVIC, and RTD (p < 0.001) and shorter TPTtwitch (p < 0.001) but not normalized RTD (p = 0.184) or normalized EMG-RMSRTD (p = 0.317). These results suggest that the leg phase angle can be an indicator of voluntary and evoked muscle contractile properties but not the neuromuscular activity of the plantar flexors, irrespective of sex and age.

Low skeletal muscle quality extracted from CT is associated with poor outcomes in severe acute pancreatitis patients

PurposeTo evaluate the association between body composition parameters derived from computed tomography (CT) scans and clinical outcomes in patients with severe acute pancreatitis (AP). MethodsPatients who have been diagnosed AP with a CT scan at ICU admission were included. Body composition parameters were measured on a single slice at L2-3 of the unenhanced CT scans. The intermuscular adipose tissue (IMAT), visceral adipose tissue (VAT), skeletal muscle area (SMA) and skeletal muscle density (SMD) were assessed using HUs by image analysis software. Univariable and multivariable analyses were performed to analyze the association between body composition parameters and clinical outcomes including all-cause mortality or prolonged ICU stay. The area under the curve (AUC) of a receiver operating characteristic curve was used to explore the predictive value of the body composition on treatment clinical outcomes. ResultsA total of 158 patients were included. The IMAT (8.3 cm2 vs 6.0 cm2, P = 0.001) and VAT (190.3 cm2 vs 143.7 cm2, P < 0.001) were significantly higher in the severe AP group than in the moderately severe group, but were notassociatedwithoutcomes. For 1 HU of SMD increased, the risk of poor clinical outcomes decresed 11 % (adjusted OR 0.892, 95 %CI 0.806–0.987, P = 0.026), while an SMD below the median value (32.1 HU for males and 28.5 HU for females) was independently associated with worse outcomes in the multivariable analysis (adjusted OR 8.868, 95 % CI 2.146–36.650, P = 0.003). The SMD had a good predictive ability for clinical outcomes, AUC was 0.824 (95 % CI, 0.715–0.933) for males and 0.803 (95 % CI, 0.639–0.967) for females. ConclusionLow SMD was associated with poor outcomes in patients with severe and moderately severe AP and might be used as a novel marker to predict outcomes in patients suffering from severe and moderately severe AP.

Research progress on the predictive role of sarcopenia in the course and prognosis of inflammatory bowel disease.

Sarcopenia is a syndrome characterized by a progressive and extensive decrease in skeletal muscle quality and function. With the development of imaging technology in recent years, the understanding and research on the pathogenesis, diagnosis, and evaluation of sarcopenia have gradually improved. More than one-third of patients with inflammatory bowel disease (IBD) have sarcopenia (Ryan et al., 2019), and as a new and unique body composition evaluation index, it is critical for predicting the clinical course, prognosis and postoperative complications of patients with IBD. However, there are limited research summarizing the prevalence of sarcopenia among IBD. Furthermore, there is a scarcity of studies establishing the precise criteria for diagnosing sarcopenia in these patients. This article summarizes the evaluation of sarcopenia and its recent advancements in predicting the course and prognosis of IBD.

Effects of pulmonary-based Qigong exercise in stable patients with chronic obstructive pulmonary disease: a randomized controlled trial

BackgroundPhysical exercise training is the central component of pulmonary rehabilitation. This study aimed to further investigate the rehabilitative effects of pulmonary-based Qigong exercise (PQE) in stable patients with chronic obstructive pulmonary disease (COPD).MethodsIn this randomized, assessor-blinded clinical trial, 44 participants with stable COPD were randomly assigned to 2 groups in a 1:1 ratio. Participants in the control group received usual care for 3 months. Participants in the intervention group received usual care combined with PQE (60 min each time, 2 times per day, 7 days per week, for 3 months). The outcome included exercise capacity, lung function test, skeletal muscle strength, dyspnea, and quality of life were measured before and after intervention.ResultsA total of 37 participants completed the trial. Compared to the control group, after 3 months of PQE, the mean change in exercise capacity, skeletal muscle strength, and quality of life were statistically significant (P < 0.05, for each), but no significant differences were observed in lung function (except for the forced expiratory volume in one second) and dyspnea (P > 0.05, for each).ConclusionThe findings of study suggest that the proposed program of 3 months of PQE intervention has significant improvement in exercise capacity, skeletal muscle strength, and quality of life of COPD-stable patients.Trial registrationThis study was registered in the Chinese Clinical Trial Registry (Trial ID: ChiCTR-1800017405 on 28 July 2018; available at https://www.chictr.org.cn/showproj.html?proj=28343).

Cigarette smoking and disproportionate changes of thoracic skeletal muscles in low-dose chest computed tomography

Association between smoking intensity and the quantity and quality of thoracic skeletal muscles (TSMs) remains unexplored. Skeletal muscle index (SMI; skeletal muscle area/height2) and percentage of normal attenuation muscle area (NAMA%) were measured to represent the quantity and quality of the skeletal muscles, respectively, and quantification was performed in pectoralis muscle at aortic arch (AA-PM), TSM at carina (C-TSM), erector spinae muscle at T12 (T12-ESM), and skeletal muscle at L1 (L1-SM). Among the 258 men (median age, 62 years [IQR: 58–69]), 183 were current smokers (median smoking intensity, 40 pack-years [IQR: 30–46]). SMI and NAMA% of AA-PM significantly decreased with pack-year (β = − 0.028 and − 0.076; P < 0.001 and P = 0.021, respectively). Smoking intensity was inversely associated with NAMA% of C-TSM (β = − 0.063; P = 0.001), whereas smoking intensity showed a borderline association with SMI of C-TSM (β = − 0.023; P = 0.057). Smoking intensity was associated with the change in NAMA% of L1-SM (β = − 0.040; P = 0.027), but was not associated with SMI of L1-SM (P > 0.05). Neither NAMA% nor SMI of T12-ESM was affected by smoking intensity (P > 0.05). In conclusion, smoking intensity was associated with the change of TSMs. Its association varied according to the location of TSMs, with the most associated parts being the upper (AA-PM) and middle TSMs (C-TSM).

Prevalence of sarcopenia and its determinants in people with type 2 diabetes: Experience from a tertiary care hospital in north India

ObjectivesChanges in skeletal muscle mass and quality are associated with type 2 Diabetes (T2D) and its complications. We evaluated the prevalence of sarcopenia in patients with T2D and its association with various anthropometric and metabolic parameters. MethodsA total of 229 patients with T2D, ≥20–60 years, were screened for sarcopenia using handgrip strength (HGS) by dynamometer, physical performance test (by Short Physical and chair stand test), and height-adjusted appendicular skeletal muscle index (ASMI) by Dual Energy X-ray Absorptiometry (DXA) applying Asian Working Group on Sarcopenia (AWGS). Multiple logistic regressions were performed to identify the factors associated with sarcopenia. ResultsThe mean age was 46.2 ± 7.4 years with 55% being women. The prevalence of low HGS, poor physical performance, low ASMI, possible sarcopenia, sarcopenia, and severe sarcopenia was 16.2%, 39.3%, 33%, 43%, 18.8%, and 6.1%, respectively. Age >45 years and use of >2 oral hypoglycaemic agents (OHA's) were risk factors for low HGS (OR:3.51, 95%CI = 1.5–8.3) and low ASMI (OR:2.40, 95%CI = 1.05, 5.49, p-0.04), respectively. Female sex (OR:3.3 1.8–6.1 p < 0.01), age >45 years (OR:2.12, 95% CI = 1.2–3.8 p-0.012) and liver fibrosis (OR: 2.12, 95% CI = 1.01–4.46 p-0.048) were independently associated with poor performance. No association was found with HbA1c, dyslipidaemia, albuminuria, hypertension, or duration of diabetes and sarcopenia. ConclusionSarcopenia is becoming increasingly recognized as a significant complication in younger individuals with T2D, and poor physical performance plays a vital role in its development. The prevalence of sarcopenia rises with advancing age, underscoring the importance of early intervention to address this condition.

Abstract 16841: Skeletal Muscle Fat Predicts Exercise Intolerance and Decreased Survival in Symptomatic Heart Failure With Preserved Ejection Fraction

Introduction: Heart failure with preserved ejection fraction (HFpEF) is characterized by marked exercise intolerance (EI) and increased mortality. HFpEF is now thought to involve multi-organ dysfunction and skeletal muscle (SkM) changes including muscle loss and muscle fatty infiltration have been reported in HFpEF patients. However, it is not known if SkM changes are associated with cardiovascular (CV) mortality. Hypothesis: Skeletal muscle fat accumulation in symptomatic HFpEF patients is associated with worse EI and decreased survival. Methods: Patients with a clinical diagnosis of HFpEF and left ventricular ejection fraction &gt; 50% (n=64, age 65.2±11.2, BMI 38.6±8.2, mean±SD, 53% women) underwent 3T conventional magnetic resonance imaging (MRI) of the calf muscle to determine SkM mass and T2-weighted MRI for SkM fat fraction (FF) with subcutaneous fat excluded. Baseline EI was quantified by six-minute walk distance (6MW). HFpEF patients were followed prospectively for a minimum of 18 months for survival (median follow up 39.3 months). Simple linear regression was used to determine relationships with EI while Kaplan-Meier survival curves with log rank tests were created to explore CV mortality. Results: SkM FF was closely and inversely associated with 6MW (1A), but SkM mass (1B) was not, indicating that EI in HFpEF is more closely associated with SkM quality than quantity. SkM FF was not related to body mass index (BMI) (1C). When the HFpEF cohort was stratified based on median FF (median=18.79%), SkM FF predicted significantly worse survival from CV death (1D, p=0.0192). Conclusions: This is the first report to show that SkM fat content predicts cardiovascular mortality in HFpEF patients. Further, EI in HFpEF patients is closely associated with SkM fat accumulation but not sarcopenia. Thus, reducing SkM fat content may represent a new target for reducing EI and improving CV survival in HFpEF patients.

Research progress on the effects of adverse exposure during pregnancy on skeletal muscle function in the offspring.

Skeletal muscle plays a crucial role in maintaining metabolism, energy homeostasis, movement, as well as endocrine function. The gestation period is a critical stage for myogenesis and development of the skeletal muscle. Adverse environmental exposures during pregnancy may impose various effects on the skeletal muscle health of the offspring. Maternal obesity during pregnancy can mediate lipid deposition in the skeletal muscle of the offspring by affecting fetal skeletal muscle metabolism and inflammation-related pathways. Poor dietary habits during pregnancy, such as high sugar and high fat intake, can affect autophagy of skeletal muscle mitochondria and reduce the quality of the offspring skeletal muscle. Nutritional deficiencies during pregnancy can affect the development of the offspring skeletal muscle through epigenetic modifications. Gestational diabetes may affect the function of the offspring skeletal muscle by upregulating the levels of miR-15a and miR-15b in the offspring. Exposure to environmental endocrine disruptors during pregnancy may impair skeletal muscle function by interfering with insulin receptor-related signaling pathways. This article reviews the research progress on effects and possible mechanisms of adverse maternal exposures during pregnancy on the offspring skeletal muscle function based on clinical and animal studies, aiming to provide scientific evidence for the prevention and treatment strategies of birth defects in the skeletal muscle.

Impact of changes in skeletal muscle mass and quality during the waiting time on outcomes of lung transplantation.

The association of changes in skeletal muscle mass and quality during the waiting time with outcomes of lung transplantation (LT) remains unclear. We aimed to examine the association of changes in skeletal muscle mass and quality during the waiting time, as well as preoperative skeletal muscle mass and quality, with outcomes of LT. This study included individuals who underwent LT from brain-dead donors. Skeletal muscle mass (cm2 /m2 ) and quality (mean Hounsfield units [HU]) of the erector spinae muscle at the 12th thoracic level were evaluated using computed tomography. Preoperative skeletal muscle mass and quality, and their changes during the waiting time were calculated. We evaluated the associations among mechanical ventilation (MV) duration, intensive care unit (ICU) length of stay (LOS), hospital LOS, 6-minute walk distance at discharge, and 5-year survival after LT. This study included 98 patients. The median waiting time was 594.5days (interquartile range [IQR], 355.0-913.0). The median changes in skeletal muscle mass and quality were -4.4% (IQR, -13.3-3.1) and -2.9% (IQR, -16.0-4.1), respectively. Severe low skeletal muscle mass at LT was associated with prolonged ICU LOS (B=8.46, 95% confidence interval [CI]: .51-16.42) and hospital LOS (B=36.00, 95% CI: 3.23-68.78). Pronounced decrease in skeletal muscle mass during the waiting time was associated with prolonged MV duration (B=7.85, 95% CI: .89-14.81) and ICU LOS (B=7.97, 95% CI: .83-15.10). Maintaining or increasing skeletal muscle mass during the waiting time would be beneficial to improve the short-term outcomes of LT.