Reduction In Skeletal Muscle Mass Research Articles

Abstract 4121348: Impairments in Left Atrioventricular Coupling Underpins Reductions in Skeletal Muscle Mass and Function in Ageing Older Adults

Background: Age-related cardiovascular disease (CVD) may manifest with changes in left ventricular (LV) systolic or left atrial (LA) dysfunction. Alterations in functional performance between the LV and LA chambers characterized by LA-LV coupling may be a sensitive marker representative of impairments in global cardiac performance, compared to either chamber alone. The increasing relevance of skeletal muscle function towards cardiac health in ageing, motivated our current work that investigated associations between skeletal muscle function and LA-LV coupling. Aim : Using advanced cardiac magnetic resonance (CMR) that characterizes cardiac volumetric parameters and strain functions, we determined the association between handgrip strength (HGS) and appendicular lean mass (ALM) with left atrioventricular coupling index (LACI). Methods: Community older adults without CVD underwent simultaneous assessment of HGS by hand dynamometer, height-square adjusted ALM by bio-impedance, and LA phasic function (namely reservoir, conduit, booster strain) as well as LA and LV volumetric parameters by CMR feature tracking. LACI is defined as the ratio of the ratio of LA to LV end-diastolic volumes. We performed linear regression and multivariable logistic regression to examine the relationship between HGS/ALM and LACI. Results: Among 251 study participants (mean age: 71 ± 9.1 years, female 44.7%), 149 (59%) had impaired LACI. HGS was linearly associated with LACI (β=-0.004, p=0.003) and LVEDV (β=1.62, p<0.0001), and ALM was linearly associated with LA volume (β=0.55, p=0.018) and LVEDV (β=3.45, p<0.0001) (Figure.1). Participants with impaired LACI (> 25%) had lower HGS (mean=22.8 ± 7.1 kg vs 26.1 ± 6.4 kg, p= 0.0002), lower ALM (16.4 ± 4.2 kg/m2 vs 17.7 ± 3.8 kg/m2, p=0.014), higher LA volume (36.8 ± 15.2 ml vs 22.0 ± 5.5 ml, p < 0.0001) and lower LV end-diastolic volume (101.0 ± 24.2 ml vs 111.9 ± 27.3 ml, p = 0.0011). The association between impaired LA-LV coupling and lower HGS (β=-0.0647, 95%CI -0.0255, -0.1040, p=0.001) and lower ALM (β=-0.0776, 95%CI -0.0107, -0.1444, p=0.011) persisted after adjusting for age. Conclusion: Reduced HGS and ALM among community-dwelling older adults was associated with impaired LA-LV coupling suggestive of underlying early-stage LA remodelling and impairments in left atrioventricular compliance. Detection of reduced HGS and ALM in community cohorts may prompt early identification of older adults at risk of dysfunctional cardiac aging.

Sleep duration, sleep disturbances and skeletal muscle mass change over time: A population-based longitudinal analysis in Peru

Background The skeletal muscle has mainly a structural function and plays a role in human’s metabolism. Besides, the association between sleep quality and muscle mass, in the form of sarcopenia, has been reported. This study aimed to assess whether changes of skeletal muscle mass (SMM) over time are associated with baseline sleep duration and disturbances in a resource-constrained adult Peruvian population. Materials and Methods Secondary analysis using information of a population-based intervention. The outcome was SMM assessed using bioimpedance and the second version of the Lee’s formula. The exposures were baseline self-reported sleep duration (normal, short and long sleepers) and disturbances (sleep difficulties and awakening at nights). Crude and adjusted linear mixed models were used to assess the associations of interest, and coefficients (β) and 95% confidence intervales (95% CI) were reported. Results Data from 2,310 individuals at baseline, mean age 43.4 (SD: 17.2), and 1,163 (50.4%) females were analyzed. Sleep duration was 7.8 (SD: 1.3) hours/day, with 15.3% short sleepers and 11.6% long sleepers, whereas 24.2% reported sleep difficulties and 25.1% awakening at nights. In multivariable model, SMM among short and long sleepers did not vary significantly over time using the Lee’s formula; however, SMM was lower at the end of follow-up for long sleepers using bioimpedance (-0.26 kg; 95% CI: -0.47 to -0.06). Sleep disturbances were associated with a gradual SMM reduction: 0.36 kg using bioimpedance and 0.25 kg using the formula at the end of follow-up. Conclusions Using bioimpedance and formula estimations, sleep disturbances were associated with a reduction of SMM over a period of 2.4 years. Regarding sleep duration, no SMM changes over time were seen in short sleepers, but findings were discordant in long sleepers: a reduction of SMM using bioimpedance, but no change using the formula.

Sleep duration, sleep disturbances and skeletal muscle mass change over time: A population-based longitudinal analysis in Peru

Background The skeletal muscle has mainly a structural function and plays a role in human’s metabolism. Besides, the association between sleep quality and muscle mass, in the form of sarcopenia, has been reported. This study aimed to assess whether changes of skeletal muscle mass (SMM) over time are associated with baseline sleep duration and disturbances in a resource-constrained adult Peruvian population. Materials and Methods Secondary analysis using information of a population-based intervention. The outcome was SMM assessed using bioimpedance and the second version of the Lee’s formula. The exposures were baseline self-reported sleep duration (normal, short and long sleepers) and disturbances (sleep difficulties and awakening at nights). Crude and adjusted linear mixed models were used to assess the associations of interest, and coefficients (β) and 95% confidence intervales (95% CI) were reported. Results Data from 2,310 individuals at baseline, mean age 43.4 (SD: 17.2), and 1,163 (50.4%) females were analyzed. Sleep duration was 7.8 (SD: 1.3) hours/day, with 15.3% short sleepers and 11.6% long sleepers, whereas 24.2% reported sleep difficulties and 25.1% awakening at nights. In multivariable model, SMM among short and long sleepers did not vary significantly over time using the Lee’s formula; however, SMM was lower at the end of follow-up for long sleepers using bioimpedance (-0.26 kg; 95% CI: -0.47 to -0.06). Sleep disturbances were associated with a gradual SMM reduction: 0.36 kg using bioimpedance and 0.25 kg using the formula at the end of follow-up. Conclusions Using bioimpedance and formula estimations, sleep disturbances were associated with a reduction of SMM over a period of 2.4 years. Regarding sleep duration, no SMM changes over time were seen in short sleepers, but findings were discordant in long sleepers: a reduction of SMM using bioimpedance, but no change using the formula.

Pretreatment Computed Tomography-Defined Sarcopenia, Treatment-Associated Muscle Loss, and Survival in Patients With Cervical Cancer: A Systematic Review and Meta-Analysis.

Sarcopenia has been identified as a potential predictor of poor prognosis in various types of cancer. However, the impact of pretreatment sarcopenia and the reduction of skeletal muscle mass during treatment on survival outcomes of patients with cervical cancer is still not well understood. This meta-analysis was conducted to investigate the impact of pretreatment sarcopenia and treatment-associated muscle loss on survival outcomes in patients with cervical cancer. The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies exploring the relationship between muscle loss and the prognosis of cervical cancer until January 1, 2023. The hazard ratios (HRs) and 95% CIs for overall survival (OS) and progression-free survival (PFS) were extracted. The data were analyzed using R software. The studies' quality was assessed using the Quality in Prognostic Studies tool. Twelve observational studies involving 1498 patients with cervical cancer were included in the analysis, with a prevalence of sarcopenia ranging from 24.8% to 57.5%. Sarcopenia was an independent predictor of poor OS (HR, 1.68; 95% CI, 1.28-2.21; P < .01) and PFS (HR, 1.53; 95% CI, 1.19-1.98; P < .01) in patients with cervical cancer. Additionally, the decrease in skeletal muscle during treatment was also significantly related to the OS (HR, 4.46; 95% CI, 2.87-6.94; P < .01) and PFS (HR, 2.89; 95% CI. 1.83-4.55; P < .01). The prevalence of pretreatment sarcopenia was high among patients with cervical cancer. Pretreatment sarcopenia and skeletal muscle loss during treatment both negatively affected prognosis in cervical cancer.

Resveratrol as a potential therapeutic agent for sarcopenic obesity: Insights from in vivoperiments

Sarcopenic obesity (SO) is a metabolic disorder with increasing prevalence. It is characterized by a reduction in skeletal muscle mass and strength. Resveratrol (RSV) is one of the most frequently used herbs in the treatment of skeletal muscle atrophy. However, the precise mechanism of the action of RSV in SO remains unclear. The objective of this study was to examine the pharmacological mechanism of RSV in the context of SO through the lens of network pharmacology, to validate these findings through in vivo experimentation. A list of potential RSV targets was compiled by retrieving the data from multiple databases. This list was then cross-referenced with a list of potential targets related to SO. The intersections of RSV- and SO-related targets were analyzed using Venn diagrams. To identify the core genes, a protein-protein interaction (PPI) network of the intersection targets was constructed and subsequently analyzed. Molecular docking was used to predict RSV binding to its core targets. A high-fat diet was used to induce SO in mice. These findings indicated that RSV may prevent SO by acting on 11 targets. Among these, interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor (TNF) are considered core targets. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results indicated that the anti-SO effect of RSV was predominantly linked to metabolic disease-related pathways, including those associated with nonalcoholic fatty liver disease. The anti-inflammatory effects of RSV were confirmed in vivo in an SO mouse model. This study contributes to a more comprehensive understanding of the key mechanisms of the action of RSV against SO and provides new possibilities for drug development in the pathological process of SO.

Risk Factors of Sarcopenia in COPD Patients: A Meta-Analysis.

Sarcopenia is a common complication of COPD associated with an age-related reduction in skeletal muscle mass associated with decreased muscle strength and / or reduced mobility. The incidence of sarcopenia in patients with COPD is twice that of non-COPD patients and is associated with poor prognosis, this study aimed to investigate the influencing factors of sarcopenia in COPD patients. Selected studies from PubMed, Embase, Web of Science, Cochrane Library, Wanfang, Wanfang, CNKI, CBM, and Wanfang databases as of November 12023. Patients aged 18 were selected; data were then independently extracted by two reviewers using a standard data collection form. In total, 17 articles reporting on 5408 patients were included. Age (OR = 1.083; 95% CI, 1.024-1.145), ALB (OR = 0.752; 95% CI, 0.724-0.780), BMI(OR = 0.701; 95% CI, 0.586-0.838), smoking (OR = 1.859; 95% CI, 1.037-3.334), diabetes (OR = 1.361; 95% CI, 1.095-1.692), qi deficiency (OR = 9.883; 95% CI, 2.052, 47.593), GOLD C (OR =2.232; 95% CI, 1.866, 2.670) and GOLD D (OR = 2.195; 95% CI, 1.826-2.637) were factors affecting muscle loss in COPD patients. Sarcopenia is more prevalent in patients with COPD. Age, body mass index, smoking, diabetes mellitus, qi deficiency, ALB, and GOLD grade were the contributing factors for sarcopenia in patients with chronic obstructive pulmonary disease. In the future, medical staff should not only pay attention to the early screening of sarcopenia in high-risk groups, but also provide relevant prevention information.

Sarcopenia adversely impacts clinical outcomes in patients undergoing pancreaticoduodenectomy: A systematic review and meta-analysis.

Sarcopenia is a syndrome marked by a gradual and widespread reduction in skeletal muscle mass and strength, as well as a decline in functional ability, which is associated with malnutrition, hormonal changes, chronic inflammation, disturbance of intestinal flora, and exercise quality. Pancreatoduodenectomy is a commonly employed clinical intervention for conditions such as pancreatic head cancer, ampulla of Vater cancer, and cholangiocarcinoma, among others, with a notably high rate of postoperative complications. Sarcopenia is frequent in patients undergoing pancreatoduodenectomy. However, data regarding the effects of sarcopenia in patients undergoing pancreaticoduodenectomy (PD) are both limited and inconsistent. To assess the influence of sarcopenia on outcomes in patients undergoing PD. The PubMed, Cochrane Library, Web of Science, and Embase databases were screened for studies published from the time of database inception to June 2023 that described the effects of sarcopenia on the outcomes and complications of PD. Two researchers independently assessed the quality of the data extracted from the studies that met the inclusion criteria. Meta-analysis using RevMan 5.3.5 and Stata 14.0 software was conducted. Forest and funnel plots were used, respectively, to demonstrate the outcomes of the sarcopenia group vs the non-sarcopenia group after PD and to evaluate potential publication bias. Sixteen studies encompassing 2381 patients were included in the meta-analysis. The patients in the sarcopenia group (n = 833) had higher overall postoperative complication rates [odds ratio (OR) = 3.42, 95% confidence interval (CI): 1.95-5.99, P < 0.0001], higher Clavien-Dindo class ≥ III major complication rates (OR = 1.41, 95%CI: 1.04-1.90, P = 0.03), higher bacteremia rates (OR = 4.46, 95%CI: 1.42-13.98, P = 0.01), higher pneumonia rates (OR = 2.10, 95%CI: 1.34-3.27, P = 0.001), higher pancreatic fistula rates (OR = 1.42, 95%CI: 1.12-1.79, P = 0.003), longer hospital stays (OR = 2.86, 95%CI: 0.44-5.28, P = 0.02), higher mortality rates (OR = 3.17, 95%CI: 1.55-6.50, P = 0.002), and worse overall survival (hazard ratio = 2.81, 95%CI: 1.45-5.45, P = 0.002) than those in the non-sarcopenia group (n = 1548). However, no significant inter-group differences were observed regarding wound infections, urinary tract infections, biliary fistulas, or postoperative digestive bleeding. Sarcopenia is a common comorbidity in patients undergoing PD. Patients with preoperative sarcopenia have increased rates of complications and mortality, in addition to a poorer overall survival rate and longer hospital stays after PD.

Clinical impact of postoperative changes in body composition on long-term outcomes in patients with esophageal cancer

Background & AimsThis study aimed to investigate the temporal changes in body composition following esophagectomy in patients with esophageal cancer using bioelectrical impedance analysis and to assess the prognostic implications of these changes. MethodsOur study included 528 patients who underwent esophagectomy and preoperative body composition measurements between January 2013 and June 2020. Postoperative body composition was measured in 493 patients at discharge as follows: 184 at 1 month, 144 at 2 months, 143 at 3 months, 103 at 6 months, 58 at 9 months, and 78 at 12 months. ResultsBody weight (BW) continuously decreased until the 6 postoperative months (POMs), reaching –11.5% compared with preoperative levels. Subsequently, almost no change was observed at 12 POMs. Skeletal muscle mass (SMM) decreased until 3 POMs but gradually recovered after 3 POMs. Conversely, body fat mass (BFM) consistently decreased over time post-esophagectomy. The patients were categorized into moderate (> –10%) and severe (≤ –10%) groups based on % BW, % SMM, and % BFM losses at 3 POMs. Severe SMM loss at 3 POMs correlated with reduced overall survival (OS) (3-year OS: 85.9% in moderate vs. 75.1% in severe, p = 0.035). BFM loss was associated with reduced recurrence-free survival. (3-year RFS: 83.3% in moderate vs. 62.0% in severe, p = 0.011). Multivariate analysis identified pStages Ⅲ and Ⅳ, % SMM loss ≤ –10%, and % BFM loss ≤ –10% as independent factors for worse OS. ConclusionPost-esophagectomy, distinct temporal changes in BW, SMM, and BFM are observed. Significant reductions in SMM and BFM 3 POMs indicate a poor long-term prognosis.

Relationship between Subjective Grip Strength and Physical Functioning among Community-Dwelling Older Women.

This study investigated the relationship between subjective grip strength and physical function in community-dwelling older women. Subjective grip strength was assessed using a questionnaire, and physical function and body composition were compared between groups with strong and weak subjective grip strength. Additionally, the two groups were compared in those with mild cognitive impairment (MCI) and those with normal cognitive function, respectively. The results showed significant differences in grip strength (p < 0.001), 30 s chair-stand (CS-30) test (p = 0.039), timed up-and-go (TUG) test (p = 0.027), maximal gait speed (p = 0.029), and skeletal muscle mass (p < 0.001). Older adults with normal cognitive function showed significant differences in grip strength (p < 0.001), quadriceps muscle strength (p < 0.009), one-leg standing time (p = 0.041), CS-30 (p = 0.002), TUG (p = 0.014), gait speed (p = 0.006), and skeletal muscle mass (p = 0.003). Older adults with low subjective grip strength had lower physical function and skeletal muscle mass. However, no items showed significant differences between groups among older adults with MCI. Thus, subjective grip strength is an indicator of an overall decline in physical function and a reduction in skeletal muscle mass in older adults, and cognitive function should be considered when assessing subjective grip strength in older adults.

Skeletal Muscle Mass Index Reduction Rate as a Prognostic Indicator for Patients Undergoing Pancreatectomy for Pancreatic Cancer.

There have been many studies on skeletal muscle depletion before surgery, and skeletal muscle depletion is a known risk factor for poor prognosis. However, reports on the association between changes in skeletal muscle mass and prognosis after surgery for pancreatic cancer are very few. The data of 137 patients who underwent pancreatectomy for pancreatic cancer between 2005 and 2022 were reviewed. Muscle areas were measured at the third lumbar vertebral level, and skeletal muscle mass index (SMI) reduction rates were calculated. Patients were divided into two groups using receiver operating characteristic (ROC) curve analysis based on the SMI reduction rate with a cutoff of 14% reduction rate. The clinicopathological factors, overall survival (OS), and recurrence-free survival (RFS) were compared between the two groups. Survival rates were analyzed both univariately and multivariately to clarify the factors associated with poor prognosis after pancreatectomy. A total of 102 patients met the inclusion criteria. SMI reduction rate ≥14% significantly correlated with advanced age and higher incidence of postoperative complications. In the multivariate Cox regression analysis, preoperative prognostic nutritional index (PNI) <40 and SMI reduction rate ≥14% were significantly associated with poor OS. Tumor size ≥3.0 cm, preoperative neutrophile-lymphocyte ratio ≥3.0, and SMI reduction rate ≥14% were significantly associated with poor RFS. The rate of skeletal muscle mass reduction after pancreatic surgery is an independent prognostic factor for survival in patients with pancreatic cancer.

Effects of Aging and Fatigue on Human Skeletal Muscle Cellular Contractile Function

Aging is associated with a reduction in skeletal muscle mass and function, known as sarcopenia. While reductions in contractile force are typically explained by loss in muscle cellular cross sectional area (CSA) loss of contractile power during high velocity contractions exceed reductions in force and cannot be solely explained by loss of muscle size and are observed at the single fiber within the same myosin heavy chain isoform (MHC). These phenomenon may be explained by myosin binding protein C (MyBP-C), which is known to modulate contractile force and velocity in a phosphorylation-dependent manner in both cardiac and skeletal muscle. Few studies have investigated the inherent contractile performance of single fibers between old and young adults, and none have explored the effects of altered MyBP-C phosphorylation on single fiber function. Therefore, the PURPOSE of this study was to investigate the effects of age and fatigue-induced MyBP-C phosphorylation on single fiber contractile performance. We HYPOTHESIZED that isometric tension will be enhanced in older adults but velocity and power will be reduced, and fatigue will enhance velocity and power in single fibers. To test this hypothesis, we recruited 4 young (18-35) and 3 older (65-80) adult males to perform a single bout of unilateral knee extensions at 30% maximal voluntary isometric contraction (MVIC) until task failure. Immediately following, a bilateral biopsy of the vastus lateralis (VL) muscle was performed on the fatigued and non-fatigued control limbs. Tissue was either flash frozen for western blot or prepared for mechanical analysis of single fiber tension (Tmax), velocity (Vmax), and power (Pmax) under optimal intracellular metabolic conditions. Our analyses were limited to MHC IIA due to differences in fiber type distribution between the groups. Our RESULTS showed that neither age nor fatigue had an effect on contractile performance in MHC IIA fibers. However, independent analysis of fatigue within age groups suggest trends towards an increase in velocity (p=0.055) in young (MHC IIA) and reduction in tension (p=0.085) in old (MHC I) adult fibers. We CONCLUDE that fatigue may modulate contractile function in the single fiber in an age- and fiber-type dependent manner. Future studies will be aimed at collecting multiple fiber types and investigating the role of biological sex. Wu Tsai Human Performance Alliance. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

P329 Sarcopenia is a risk factor of post-operative recurrence of Crohn’s disease

Abstract Background Sarcopenia is defined as reduction in skeletal muscle mass and muscle strength; it was found in up to 50% of patients with Crohn's disease (CD) in several studies.In CD patients sarcopenia is a risk factor for surgery, post-operative complications and worse surgical outcomes; furthermore, it is a negative prognostic factor for endoscopic remission in patients treated with biologics.The aim of our study was to evaluate the impact of sarcopenia on endoscopic recurrence at 6-12 months follow-up in CD patients after ileo-colic resection. Methods CD patients undergoing primary elective ileo-colic resection surgery between 2013 and 2023 were enrolled. Patients with previous intestinal surgery, pre-operative complications (abscess, perforation) and immunosuppressive or biologic therapy after surgery were excluded. Sarcopenia was defined as the sex- and height-adjusted Total Psoas Area Index (TPAI) lower than 5.4 cm2/m2 (men) and 3.56 cm2/m2 (women), calculated at the level of the third lumbar vertebra on MRI scans performed within 3 months before surgery. Already known risk factors for post-surgical disease recurrence were considered. Uni- and multi-variate analyses were performed to evaluate if sarcopenia before surgery could influence endoscopic recurrence (Rutgeers score ≥ i2) of disease 6-12 months after surgery. Results Seventy-two CD patients were included. Endoscopic recurrence (at 6-12 months follow-up colonscopy) was found in 22% of patients and it was associated with the presence of pre-operative sarcopenia (1.4% vs 15.3%;p&amp;lt;0.001) and surgical complications (2.78% vs 6.94%;p=0.024), while it was not associated with comorbidies, familiarity, smoke, extension of resection or pre-operative therapy, PCR and albumin. Sarcopenia was identify as predictor of endoscopic recurrence (OR=25;p=0.005) as well as surgical complications after resection (OR=99.7;p=0.032). Neither medical or surgical complications showed statistically significant correlation with the presence of pre-operative sarcopenia (p=0.819). Conclusion Sarcopenia in CD patients before surgery seems to be an independent prognostic factor for endoscopic recurrence. Perioperative interventions to improve sarcopenia may have positive impact on surgical outcomes and disease recurrence.

A Study of the Relationship Between the Triglyceride-Glucose Index and Skeletal Muscle Mass in a General Chinese Population.

There is no study on the relationship between triglyceride-glucose index (TyG index) and skeletal muscle mass in middle-aged and elderly C population. Therefore, the aim of the study is to investigate the relationship between the TyG index and weight-adjusted relative skeletal muscle index (RSMI) in middle-aged and elderly C population. We retrospectively studied 947 aged ⩾40 years subjects who got a routine medical examination in the Department of Geriatrics of R Hospital from May 2021 to March 2023. The RSMI was designed to evaluate skeletal muscle mass and calculated based on lean mass of the limbs(kg)/body weight(kg) × 100%. Skeletal muscle mass reduction was defined as a RSMI of 1-2 standard deviations (SD) below of healthy adults aged 30-49 years old. Considering the quartile groups of the TyG index, the subjects were assigned to 4 groups: Q1 (less than or equal to 8.171), Q2 (from 8.172 to 8.569), Q3 (from 8.570 to 8.992), and Q4 (greater than or equal to 8.993). With TyG index increased, RSMI levels significantly reduced(P < .001). Spearman's correlation analysis showed that the TyG index was negatively correlated with RSMI in males (r = -0.320) and females (r = -0.240). The TyG index was positively correlated with body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) (P < .05). Besides, binary logistic regression analysis showed that the risk of developing reduced skeletal muscle mass in the group Q4 was 2.131 (95%CI:1.118-4.064) in males; and was 2.472 (95%CI:1.581-3.867) in females compared to the Q1 group. TyG index was negatively correlated with relative skeletal muscle index, and a higher TyG index was associated with the development of reduced skeletal muscle mass independently of other influencing factors. Therefore, the TyG index promises to be a predictor of skeletal muscle mass loss.

Prognosis analysis after recurrence of preoperative skeletal muscle mass reduction group in colorectal cancer stage Ⅱ/Ⅲ

Prognosis analysis after recurrence of preoperative skeletal muscle mass reduction group in colorectal cancer stage Ⅱ/Ⅲ

Proportion of caloric restriction-induced weight loss as skeletal muscle.

This study's objective was to develop models predicting the relative reduction in skeletal muscle (SM) mass during periods of voluntary calorie restriction (CR) and to validate model predictions in longitudinally monitored samples. The model development group included healthy nonexercising adults (n = 897) who had whole-body SM mass measured with magnetic resonance imaging. Model predictions of relative SM changes with CR were evaluated in two longitudinal studies, one 12 to 14 weeks in duration (n = 74) and the other 12 months in duration (n = 26). A series of SM prediction models were developed in a sample of 415 males and 482 females. Model-predicted changes in SM mass relative to changes in body weight (i.e., ΔSM/Δbody weight) with a representative model were (mean ± SE) 0.26 ± 0.013 in males and 0.14 ± 0.007 in females (sex difference, p < 0.001). The actual mean proportions of weight loss as SM in the longitudinal studies were 0.23 ± 0.02/0.20 ± 0.06 in males and 0.10 ± 0.02/0.17 ± 0.03 in females, similar to model-predicted values. Nonelderly males and females with overweight and obesity experience respective reductions in SM mass with voluntary CR in the absence of a structured exercise program of about 2 to 2.5 kg and 1 to 1.5 kg per 10-kg weight loss, respectively. These estimates are predicted to be influenced by interactions between age and body mass index in males, a hypothesis that needs future testing.

Relationships Between Skeletal Muscle Mass, Lumbar Lordosis, and Chronic Low Back Pain in the Elderly.

Loss of skeletal muscle mass is known to be associated with multiple morbidities. However, there is a dearth of reports on its association with lumbar lordosis and musculoskeletal pain. The aim of this study was to delineate the cross-sectional relationship between loss of skeletal muscle mass, lumbar lordosis, and chronic low back pain (CLBP). A total of 721 medical records were reviewed, and data from 165 older subjects (over 65 years old; 81 men and 84 women) were retrospectively analyzed. Subjects were categorized into either the CLBP group (back pain for more than 6 months; 35 men and 36 women) or the control group (46 men and 48 women). The modified skeletal muscle mass index (MSMI, appendicular skeletal muscle mass [kg]/weight [kg] × 100), assessed by bioelectrical impedance analysis, and lumbar lordotic angle (LLA) were measured and compared between the CLBP group and the control group. The correlation between MSMI and LLA was investigated. The LLA of men and women in the CLBP group was significantly lower than that of the control group (p < 0.05). The MSMI was decreased in the CLBP group compared to the control group (p < 0.05). For both sexes, positive correlations were observed between the MSMI and LLA. A close cross-sectional relationship was observed between MSMI, LLA, and CLBP. This suggests a potential interaction between the reduction in skeletal muscle mass and altered lumbar spine sagittal alignment, which could lead to CLBP.

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

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

Sarcopenia evaluation on cardiac magnetic resonance imaging in older adults for outcomes prediction following surgical aortic valve replacement

BackgroundSarcopenia refers to a reduction in skeletal muscle mass and strength. Despite the known association between single-slice muscle measurements on lumbar computed tomography and poor outcomes in various clinical settings, studies using thoracic muscle measurements on cardiac magnetic resonance imaging (CMR) have been limited. MethodsPatients undergoing surgical aortic valve replacement (SAVR) between 2010 and 2020 were included if they were ≥ 50 years of age with preoperative CMR. Manual unilateral pectoralis major and minor skeletal muscle area measurements were made at the carina and normalized for body size by height to obtain skeletal muscle index (SMI). Sarcopenia was defined as the lowest sex-stratified SMI tertile and higher-risk as the highest fiftieth percentile Society of Thoracic Surgeons' (STS) mortality score. ResultsA total of 133 patients were included, 35 (26.3%) females. The average age was 64 ± 9 years, with most Caucasian (93.2%). Compared to non-sarcopenic patients, sarcopenic patients were older with lower body mass index. During a median follow-up of 27.3 (7.6–60.4) months, 10 (22.2%) deaths occurred in the sarcopenic group and 8 (9.1%) in the non-sarcopenic group (p = 0.039 by log-rank test). On subgroup analysis (66 patients), higher-risk sarcopenic patients had 10 (37.0%) deaths compared to 8 (20.5%) in higher-risk non-sarcopenic patients (p = 0.011 by log-rank test). ConclusionsSimple unilateral pectoralis muscle measurements on preoperative CMR can be used as an adjunct to traditional risk scores for predicting mortality post-SAVR.

Impact of Skeletal Muscle Mass Reduction on Long-term Survival After Radical Resection of Gastric Cancer.

This study aimed to investigate the effect of preoperative skeletal muscle mass and muscle mass loss after surgery on overall survival in patients with gastric cancer who underwent radical resection. We also examined factors involved in postoperative skeletal muscle loss. One hundred fifty gastric cancer patients who underwent radical resection were retrospectively examined. Skeletal muscle index (SMI) was measured using computed tomography before surgery and 1 year after. Degree of muscle reduction (MR) was calculated. Patients were stratified according to preoperative SMI (high/low) and MR (high/low) for analysis. In addition, patients were grouped according to SMI and MR stratification as follows: group A, low SMI/high MR; group B, low SMI/low MR; group C, high SMI/high MR; and group D, high SMI/low MR. In multivariate analysis, preoperative SMI and MR were independent predictors of overall survival. Overall survival significantly differed among groups A, B, C, and D (p<0.0001). The list of groups in order of worsening overall survival was as follows: group D, group C, group B, and group A. In multivariate analysis, patient group according to SMI and MR stratification was an independent predictor of overall survival. MR was affected by operation time (>430 min) and surgical procedure (total gastrectomy). Preoperative SMI and reduction in skeletal muscle mass after gastric cancer surgery were significantly associated with overall survival. Long-term management of these patients should focus on maintenance of postoperative skeletal muscle mass.

Exercise mitigates Dapagliflozin-induced skeletal muscle atrophy in STZ-induced diabetic rats

BackgroundSodium-glucose cotransporter 2 inhibitors (SGLT2i) are commonly used in the management of type 2 diabetes mellitus (T2DM) and have been found to worsen the reduction of skeletal muscle mass in individuals with T2DM. This study aims to examine the potential of exercise in mitigating the skeletal muscle atrophy induced by SGLT2i treatment.MethodsA rat model of T2DM (40 male Sprague-Dawley rats; T2DM induced by a combination of high-fat diet and streptozotocin) was used to examine the effects of six-week treatment with Dapagliflozin (DAPA, SGLT2i) in combination with either aerobic exercise (AE) or resistance training (RT) on skeletal muscle. T2DM-eligible rats were randomized into the T2DM control group (CON, n = 6), DAPA treatment group (DAPA, n = 6), DAPA combined with aerobic exercise intervention group (DAPA + AE, n = 6), and DAPA combined with resistance training intervention group (DAPA + RT, n = 6). To assess the morphological changes in skeletal muscle, myosin ATPase and HE staining were performed. mRNA expression levels of Atrogin-1, MuRF1, and Myostatin were determined using quantitative PCR. Furthermore, protein expression levels of AKT, p70S6K, mTOR, FoXO1/3A, NF-κB, and MuRF1 were examined through western blotting.ResultsBoth the administration of DAPA alone and the combined exercise intervention with DAPA resulted in significant reductions in blood glucose levels and body weight in rats. However, DAPA alone administration led to a decrease in skeletal muscle mass, whereas RT significantly increased skeletal muscle mass and muscle fiber cross-sectional area. The DAPA + RT group exhibited notable increases in both total protein levels and phosphorylation levels of AKT and p70S6K in skeletal muscle. Moreover, the DAPA, DAPA + AE, and DAPA + RT groups demonstrated downregulation of protein expression (FoXO1/3A) and mRNA levels (Atrogin-1, MuRF1, and Myostatin) associated with muscle atrophy.ConclusionsOur findings provide support for the notion that dapagliflozin may induce skeletal muscle atrophy through mechanisms unrelated to protein metabolism impairment in skeletal muscle, as it does not hinder protein metabolic pathways while reduces muscle atrophy-related genes. Additionally, our observations reveal that RT proves more effective than AE in enhancing skeletal muscle mass and muscle fiber cross-sectional area in rats with T2DM by stimulating protein anabolism within the skeletal muscle.