Epidemiology of myosteatosis

Establishment and Validation of a Predictive Model for Sarcopenia Based on 2-D Ultrasound and Shear Wave Elastography in the Medial Gastrocnemius Muscle

OBJECTIVE

To develop and validate a predictive model for sarcopenia.

METHODS

A total of 240 subjects who visited our hospital between August 2021 and May 2023 were randomly divided by time of entry into a training set containing 2/3 of patients and a validation set containing 1/3 of patients. The muscle thickness (MT), echo intensity (EI), and shear wave velocity (SWV) of the medial gastrocnemius muscle were measured. Indicators that were meaningful in the univariate analysis in the training set were included in a binary logistic regression to derive a regression model, and the model was evaluated using a consistency index, calibration plot, and clinical validity curve. Diagnostic efficacy and clinical applicability were compared between the model and unifactorial indicators.

RESULTS

Four meaningful variables, age, body mass index (BMI), MT, and SWV, were screened into the predictive model. The model was Logit Y = 21.292 + 0.065 × Age - 0.411 × BMI - 0.524 × MT - 3.072 × SWV. The model was well differentiated with an internally validated C-index of 0.924 and an external validation C-index of 0.914. The calibration plot predicted probabilities against actual probabilities showed excellent agreement. The specificity, sensitivity, and Youden's index of the model were 73.80%, 97.40%, and 71.20%, respectively, when using the diagnostic cut-off value of >0.279 for sarcopenia. The logistic model had higher diagnostic efficacy (p < 0.001) and higher net clinical benefit (p < 0.001) over the same threshold range compared to indicators.

CONCLUSION

The logistic model of sarcopenia has been justified to have good discriminatory, calibrated, and clinical validity, and has higher diagnostic value than indicators.

Body composition measures as a determinant of Alpelisib related toxicity

BACKGROUND

Body composition has emerged as an important prognostic factor in patients treated with cancer. Severe depletion of skeletal muscle, sarcopenia, has been associated with poor performance status and worse oncological outcomes. We studied patients with metastatic breast cancer receiving alpelisib, to determine if sarcopenia and additional body composition measures accounting for muscle and adiposity are associated with toxicity.

METHODS

A retrospective observational analysis was conducted, including 38 women with metastatic breast cancer and a PIK3CA mutation, treated with alpelisib as advanced line of therapy. Sarcopenia was determined by measuring skeletal muscle cross-sectional area at the third lumbar vertebra using computerized tomography. Various body composition metrics were assessed along with drug toxicity, dose reductions, treatment discontinuation, hospitalizations, time to treatment failure and overall survival.

RESULTS

Sarcopenia was observed in half of the patients (n = 19, 50%), spanning normal weight, overweight, and obese individuals. Among the body composition measures, lower skeletal muscle density (SMD) was associated with an increased risk of treatment-related hyperglycaemia (P = 0.03). Additionally, lower visceral adipose tissue (VAT) was associated with alpelisib-induced rash (P = 0.04) and hospitalizations (P = 0.04). Notably, alpelisib treatment discontinuation was not impacted by alpelisib toxicity.

CONCLUSION

Body composition measures, specifically SMD and VAT may provide an opportunity to identify patients at higher risk for severe alpelisib related hyperglycemia, and cutaneous toxicity. These findings suggest the potential use of body composition assessment to caution toxicity risk, allowing for personalized therapeutic observation and intervention.

Dual-Energy CT muscle fat fraction as a new imaging biomarker of body composition and survival predictor in critically ill patients

OBJECTIVE

To analyze changes in the muscular fat fraction (FF) during immobilization at the intensive care unit (ICU) using dual-energy CT (DECT) and evaluate the predictive value of the DECT FF as a new imaging biomarker for morbidity and survival.

METHODS

Immobilized ICU patients (n = 81, 43.2% female, 60.3 ± 12.7 years) were included, who received two dual-source DECT scans (CT1, CT2) within a minimum interval of 10 days between 11/2019 and 09/2022. The DECT FF was quantified for the posterior paraspinal muscle by two radiologists using material decomposition. The skeletal muscle index (SMI), muscle radiodensity attenuation (MRA), subcutaneous-/ visceral adipose tissue area (SAT, VAT), and waist circumference (WC) were assessed. Reasons for ICU admission, clinical scoring systems, therapeutic regimes, and in-hospital mortality were noted. Linear mixed models, Cox regression, and intraclass correlation coefficients were employed.

RESULTS

Between CT1 and CT2 (median 21 days), the DECT FF increased (from 20.9% ± 12.0 to 27.0% ± 12.0, p = 0.001). The SMI decreased (35.7 cm2/m2 ± 8.8 to 31.1 cm2/m2 ± 7.6, p < 0.001) as did the MRA (29 HU ±  10 to 26 HU ± 11, p = 0.009). WC, SAT, and VAT did not change. In-hospital mortality was 61.5%. In multivariable analyses, only the change in DECT FF was associated with in-hospital mortality (hazard ratio (HR) 9.20 [1.78-47.71], p = 0.008), renal replacement therapy (HR 48.67 [9.18-258.09], p < 0.001), and tracheotomy at ICU (HR 37.22 [5.66-245.02], p < 0.001). Inter-observer reproducibility of DECT FF measurements was excellent (CT1: 0.98 [0.97; 0.99], CT2: 0.99 [0.96-0.99]).

CONCLUSION

The DECT FF appears to be suitable for detecting increasing myosteatosis. It seems to have predictive value as a new imaging biomarker for ICU patients.

CLINICAL RELEVANCE STATEMENT

The dual-energy CT muscular fat fraction appears to be a robust imaging biomarker to detect and monitor myosteatosis. It has potential for prognosticating, risk stratifying, and thereby guiding therapeutic nutritional regimes and physiotherapy in critically ill patients.

KEY POINTS

The dual-energy CT muscular fat fraction detects increasing myosteatosis caused by immobilization. Change in dual-energy CT muscular fat fraction was a predictor of  in-hospital morbidity and mortality. Dual-energy CT muscular fat fraction had a predictive value superior to established CT body composition parameters.

The effects of myosteatosis on skeletal muscle function in older adults

Myosteatosis, or the infiltration of fatty deposits into skeletal muscle, occurs with advancing age and contributes to the health and functional decline of older adults. Myosteatosis and its inflammatory milieu play a larger role in adipose tissue dysfunction, muscle tissue dysfunction, and increased passive muscle stiffness. Combined with the age-related decline of sex hormones and development of anabolic resistance, myosteatosis also contributes to insulin resistance, impaired muscle mechanics, loss of force production from the muscle, and increased risk of chronic disease. Due to its highly inflammatory secretome and the downstream negative effects on muscle metabolism and mechanics, myosteatosis has become an area of interest for aging researchers and clinicians. Thus far, myosteatosis treatments have had limited success, as many lack the potency to completely rescue the metabolic and physical consequences of myosteatosis. Future research is encouraged for the development of reliable assessment methods for myosteatosis, as well as the continued exploration of pharmacological, nutritional, and exercise-related interventions that may lead to the success in attenuating myosteatosis and its clinical consequences within the aging population.

Skeletal muscle and visceral adipose radiodensities are pre-surgical, non-invasive markers of aggressive kidney cancer

INTRODUCTION

Most studies on body composition in kidney cancer have been conducted among patients with metastatic disease. Given that aggressive tumours can adversely impact body composition and even non-metastatic tumours can be aggressive, we evaluated associations between pre-surgical body composition features and tumour pathological features in patients with non-metastatic clear cell renal cell cancer (ccRCC).

METHODS

The Resolve Cohort consists of 1239 patients with non-metastatic ccRCC who underwent nephrectomy at Memorial Sloan Kettering Cancer Center between 2000 and 2020. The cross-sectional areas and radiodensities of skeletal muscle, visceral adipose, and subcutaneous adipose tissues were determined from pre-surgical computed tomography (CT) scans at the third lumbar vertebrae using Automatica software. Pearson's correlation coefficients describe inter-relationships among BMI and body composition variables, while odds ratios (OR) and 95% confidence intervals (CI) estimate associations between continuous body composition features (per 1-standard deviation) and advanced stage (Stage III vs. Stages I-II) and high Fuhrman grade (Grades 3-4 vs. 1-2) from multivariable logistic regression models that considered the potential impact of biological sex, contrast enhanced CTs, and early age at onset of ccRCC.

RESULTS

The cohort was predominantly male (69%), white (89%), and had a median age of 58. The proportion of patients presenting with advanced stage and high-grade disease were 31% and 51%, respectively. In models that adjusted for demographics and all body composition variables simultaneously, decreasing skeletal muscle radiodensity (i.e., more fat infiltration) but increasing visceral adipose tissue radiodensity (i.e., more lipid depletion) were associated with advanced tumour features. Per 8.4 HU decrease in skeletal muscle radiodensity, the odds of presenting with advanced stage was 1.61 (95% CI: 1.34-1.93). Per 7.22 HU increase in visceral adipose tissue radiodensity, the odds of presenting with advanced stage was 1.45 (95% CI: 1.22-1.74). Skeletal muscle index (i.e., sarcopenia) was not associated with either tumour feature. Similar associations were observed for Fuhrman grade, a more direct marker of tumour aggressiveness. Associations did not differ by sex, contrast use, or age at onset of ccRCC.

CONCLUSIONS

Lipid infiltrated skeletal muscle, but lipid depleted visceral adipose tissue were independently associated with advanced tumour features in non-metastatic ccRCC. Findings highlight the importance of evaluating the full range of body composition features simultaneously in multivariable models. Interpreting pre-surgical CTs for body composition for patients may be a novel and non-invasive way to identify patients with aggressive renal tumours, which is clinically relevant as renal biopsies are not routinely performed.

Factors associated with variability in skeletal muscle radiodensity in patients with metastatic cancer

OBJECTIVES

This study aimed to explore factors associated with skeletal muscle radiodensity (SMD) variability in patients with metastatic cancer.

METHODS

This study included 393 patients (median age 61 y, 70% women) who had computed tomography (CT) scans within 30 days of inclusion in the study. SMD was evaluated from CT by averaging the Hounsfield unit value of the total muscle area. Skeletal muscle index (SMI), visceral adipose tissue index (VATI), subcutaneous adipose tissue index (SATI), and total adipose tissue index (TATI) were also assessed by CT. Additionally, age, sex, race/skin color, disease characteristics, comorbidities, inflammatory markers, handgrip strength (HGS), and body mass index (BMI) were recorded and evaluated in the linear regression analysis to identify factors associated with SMD variability.

RESULTS

Multivariate explanatory models having SMD as an independent variable were performed and included BMI (model 1, r2 = 0.699), TATI (model 2, r2 = 0.712) or VATI and SATI (model 3, r2 = 0.706) in addition to age, race/skin color, tumor site, kidney disease, serum albumin, HGS, and SMI as dependent variables. For all models, lower SMD was associated with higher age, BMI, and adiposity measurements, kidney disease, White race/skin color, and lower serum albumin, HGS, and SMI. The primary tumor site also contributed to changes in SMD in all models, specifically those located in the gastrointestinal tract, gynecologic, and bone and connective tissue.

CONCLUSION

In this group of patients with metastatic cancer, lower SMD was associated with older age, White race/skin color, and an overall worse clinical condition.

The global leadership into malnutrition criteria reveals a high percentage of malnutrition which influences overall survival in patients with gastroenteropancreatic neuroendocrine tumours

Patients with neuroendocrine tumours located in the gastroenteropancreatic tract (GEP-NETs) and treatment with somatostatin analogues (SSA's) are at risk of malnutrition which has been reported previously evaluating weight loss or body mass index (BMI) only. The global leadership into malnutrition (GLIM) criteria include weight loss, BMI, and sarcopenia, for diagnosing malnutrition. These GLIM criteria have not been assessed in patients with GEP-NETs on SSA. The effect of malnutrition on overall survival has not been explored before. The aim of this study is to describe the presence of malnutrition in patients with GEP-NET on SSA based on the GLIM criteria and associate this with overall survival. Cross-sectional study screening all patients with GEP-NETs on SSA's for malnutrition using the GLIM criteria. Body composition analysis for sarcopenia diagnosis were performed. Bloods including vitamins, minerals, and lipid profile were collected. Overall survival since the date of nutrition screening was calculated. Uni- and multivariate Cox regression analysis were performed to identify malnutrition as risk factor for overall survival. A total of 118 patients, 47% male, with median age 67 years (IQR 56.8-75.0) were included. Overall, malnutrition was present in 88 patients (75%); based on low BMI in 26 (22%) patients, based on weight loss in 35 (30%) patients, and based on sarcopenia in 83 (70%) patients. Vitamin deficiencies were present for vitamin D in 64 patients (54%), and vitamin A in 29 patients (25%). The presence of malnutrition demonstrated a significantly worse overall survival (p-value = .01). In multivariate analysis meeting 2 or 3 GLIM criteria was significantly associated with worse overall survival (HR 2.16 95% CI 1.34-3.48, p-value = .002). Weight loss was the most important risk factor out of the 3 GLIM criteria (HR 3.5 95% CI 1.14-10.85, p-value = .03) for worse overall survival. A high percentage (75%) of patients with GEP-NETs using a SSA meet the GLIM criteria for malnutrition. Meeting more than 1 GLIM criterium, especially if there is weight loss these are risk factors for worse overall survival.

Integrative cross-species analysis reveals conserved and unique signatures in fatty skeletal muscles

Fat infiltration in skeletal muscle is now recognized as a standard feature of aging and is directly related to the decline in muscle function. However, there is still a limited systematic integration and exploration of the mechanisms underlying the occurrence of myosteatosis in aging across species. Here, we re-analyzed bulk RNA-seq datasets to investigate the association between fat infiltration in skeletal muscle and aging. Our integrated analysis of single-nucleus transcriptomics in aged humans and Laiwu pigs with high intramuscular fat content, identified species-preference subclusters and revealed core gene programs associated with myosteatosis. Furthermore, we found that fibro/adipogenic progenitors (FAPs) had potential capacity of differentiating into PDE4D+/PDE7B+ preadipocytes across species. Additionally, cell-cell communication analysis revealed that FAPs may be associated with other adipogenic potential clusters via the COL4A2 and COL6A3 pathways. Our study elucidates the correlation mechanism between aging and fat infiltration in skeletal muscle, and these consensus signatures in both humans and pigs may contribute to increasing reproducibility and reliability in future studies involving in the field of muscle research.

Association of Dietary Protein Sources and Their Adequacy, Body Composition and Risk of Sarcopenic Obesity in South Korean Populations: A Cross-Sectional Study

Dietary protein sources and protein adequacy are crucial modulators of muscle quality and body composition. We investigated the association between dietary protein sources (and their adequacy) and body composition and the risk of sarcopenic obesity (SO) in South Korean populations. The participants (n = 1967) were classified into SO, obese, sarcopenia, and normal groups. A cross-sectional survey was conducted using the KS-15 questionnaire, short-form food frequency questionnaire, and anthropometric measurements. The percentage of body fat (male: 35.36 ± 0.51%; female: 44.14 ± 0.36%) was significantly high, while appendicular skeletal muscle (ASM; male: 36.39 ± 0.30%, female: 30.32 ± 0.19%) was low in the SO group. Beef and pork consumption was negatively associated with ASM (%) but positively associated with body fat (%) in the normal group and positively associated with ASM (kg/m2: beta = 0.002, p = 0.02) and BFM (kg: beta = 0.012, p = 0.03) in the SO group, respectively. The highest quintile (Q5: 173.6 g/day) showed a decreased risk of SO prevalence (AORs: 0.46, CI: 0.22-0.94) compared with that in the lowest quintile (Q1: 21.6 g/day) among the people with inadequacy protein intake. Daily poultry and egg intake was positively linked with body composition in the participants with SO, while red meat showed a negative effect on imbalanced body composition in participants in the normal and SO groups. Furthermore, a lower intake of poultry and eggs was strongly associated with SO prevalence in people who consumed inadequate amounts of daily dietary protein.

Muscle quality, physical performance, and comorbidity are predicted by circulating procollagen type III N-terminal peptide (P3NP): the InCHIANTI follow-up study

Sarcopenia is characterized by skeletal muscle quantitative and qualitative alterations. A marker of collagen turnover, procollagen type III N-terminal peptide (P3NP), seems to be related to those conditions. This study aims to assess the predictive role of P3NP in muscle density and physical performance changes. In the InCHIANTI study, a representative sample from the registry lists of two towns in Tuscany, Italy, was recruited. Baseline data was collected in 1998, and follow-up visits were conducted every 3 years. Out of the 1453 participants enrolled at baseline, this study includes 1052 participants. According to P3NP median levels, population was clustered in two groups; 544 (51.7%) of the 1052 subjects included were classified in the low median levels (LM-P3NP); at the baseline, they were younger, had higher muscle density, and performed better at the Short Physical Performance Battery (SPPB), compared to the high-median group (HM-P3NP).LM-P3NP cases showed a lower risk to develop liver chronic diseases, CHF, myocardial infarction, and osteoarthritis. HM-P3NP levels were associated with a longitudinal reduction of muscle density, and this effect was potentiated by the interaction between P3NP and leptin. Moreover, variation in physical performance was inversely associated with high level of P3NP, and directly associated with high fat mass, and with the interaction between P3NP and muscle density. Our data indicate that P3NP is associated with the aging process, affecting body composition, physical performance, and clinical manifestations of chronic degenerative age-related diseases.

Pathophysiological-Based Nutritional Interventions in Cirrhotic Patients with Sarcopenic Obesity: A State-of-the-Art Narrative Review

In recent decades, following the spread of obesity, metabolic dysfunction has come to represent the leading cause of liver disease. The classical clinical presentation of the cirrhotic patient has, therefore, greatly changed, with a dramatic increase in subjects who appear overweight or obese. Due to an obesogenic lifestyle (lack of physical activity and overall malnutrition, with an excess of caloric intake together with a deficit of proteins and micronutrients), these patients frequently develop a complex clinical condition defined as sarcopenic obesity (SO). The interplay between cirrhosis and SO lies in the sharing of multiple pathogenetic mechanisms, including malnutrition/malabsorption, chronic inflammation, hyperammonemia and insulin resistance. The presence of SO worsens the outcome of cirrhotic patients, affecting overall morbidity and mortality. International nutrition and liver diseases societies strongly agree on recommending the use of food as an integral part of the healing process in the comprehensive management of these patients, including a reduction in caloric intake, protein and micronutrient supplementation and sodium restriction. Based on the pathophysiological paths shared by cirrhosis and SO, this narrative review aims to highlight the nutritional interventions currently advocated by international guidelines, as well as to provide hints on the possible role of micronutrients and nutraceuticals in the treatment of this multifaceted clinical condition.

Body Composition Evaluation and Clinical Markers of Cardiometabolic Risk in Patients with Phenylketonuria

Cardiovascular diseases are the main cause of mortality worldwide. Patients with phenylketonuria (PKU) may be at increased cardiovascular risk. This review provides an overview of clinical and metabolic cardiovascular risk factors, explores the connections between body composition (including fat mass and ectopic fat) and cardiovascular risk, and examines various methods for evaluating body composition. It particularly focuses on nutritional ultrasound, given its emerging availability and practical utility in clinical settings. Possible causes of increased cardiometabolic risk in PKU are also explored, including an increased intake of carbohydrates, chronic exposure to amino acids, and characteristics of microbiota. It is important to evaluate cardiovascular risk factors and body composition in patients with PKU. We suggest systematic monitoring of body composition to develop nutritional management and hydration strategies to optimize performance within the limits of nutritional therapy.

Age-related Muscle Fat Infiltration in Lung Screening Participants: Impact of Smoking Cessation

Rationale

Skeletal muscle fat infiltration progresses with aging and is worsened among individuals with a history of cigarette smoking. Many negative impacts of smoking on muscles are likely reversible with smoking cessation.

Objectives

To determine if the progression of skeletal muscle fat infiltration with aging is altered by smoking cessation among lung cancer screening participants.

Methods

This was a secondary analysis based on the National Lung Screening Trial. Skeletal muscle attenuation in Hounsfield unit (HU) was derived from the baseline and follow-up low-dose CT scans using a previously validated artificial intelligence algorithm. Lower attenuation indicates greater fatty infiltration. Linear mixed-effects models were constructed to evaluate the associations between smoking status and the muscle attenuation trajectory.

Measurements and Main Results

Of 19,019 included participants (age: 61 years, 5 [SD]; 11,290 males), 8,971 (47.2%) were actively smoking cigarettes. Accounting for body mass index, pack-years, percent emphysema, and other confounding factors, actively smoking predicted a lower attenuation in both males (β0 =-0.88 HU, P<.001) and females (β0 =-0.69 HU, P<.001), and an accelerated muscle attenuation decline-rate in males (β1=-0.08 HU/y, P<.05). Age-stratified analyses indicated that the accelerated muscle attenuation decline associated with smoking likely occurred at younger age, especially in females.

Conclusions

Among lung cancer screening participants, active cigarette smoking was associated with greater skeletal muscle fat infiltration in both males and females, and accelerated muscle adipose accumulation rate in males. These findings support the important role of smoking cessation in preserving muscle health.

Body composition parameters predict survival in pancreatic cancer-A retrospective multicenter analysis

BACKGROUND

Parameters to adapt individual treatment strategies for patients with pancreatic ductal adenocarcinoma (PDAC) are urgently needed. The present study aimed to evaluate body composition parameters as predictors of overall survival (OS) in PDAC patients.

METHODS

Measurements of body composition parameters were performed on computed tomography scans at diagnosis. Height-standardized and Body Mass Index- and sex-adjusted regression formulas deriving cut-offs from a healthy population were used. The Kaplan-Meier method with the log-rank test was performed for survival analysis. Independent prognostic factors were identified with uni- and multivariable Cox regression analyses.

RESULTS

In total, 354 patients were analyzed. In a multivariable Cox model, besides tumor stage and resection status, only myosteatosis (HR 1.53; 95% CI 1.10-2.14, p = 0.01) was an independent prognostic factor of OS among body composition parameters. Subgroup analyses revealed that the prognostic impact of myosteatosis was higher in patients ≤68 years of age, with advanced tumor stages and patients without curative intended resection.

CONCLUSIONS

The analysis of one of the largest Caucasian cohorts to date, demonstrated myosteatosis to be an independent prognostic factor of OS in PDAC. To improve outcomes, prospective trials aiming to investigate the utility of an early assessment of myosteatosis with subsequent intervention by dieticians, sports medicine physicians, and physiotherapists are warranted.

Association between relative muscle strength and hypertension in middle-aged and older Chinese adults

BACKGROUND

The association between muscle defects and hypertension is well-established. However, the absence of pertinent and uncomplicated clinical indicators presents a challenge. Relative muscle strength (RMS) may offer a viable indicator. This study aimed to explore the association between RMS and hypertension.

METHODS

A total of 12,720 individuals aged ≥ 45 years from the 2011 wave of the China Health and Retirement Longitudinal Study (CHARLS) were included. Grip strength was recorded and appendicular skeletal muscle mass (ASM) was estimated using a validated mathematical formula. The RMS was calculated as the ratio of grip strength to ASM. Hypertension was determined based on previous diagnosis, history of hypertension medication use, and current blood pressure. Logistic regression models were employed to investigate the relationship between RMS and hypertension.

RESULTS

The prevalence of hypertension was 41.7% (5,307/12,720 patients). RMS was negatively correlated with hypertension with an OR (95% CI) of 0.68 (0.59-0.79) for males, 0.81 (0.73-0.90) for females, and 0.78 (0.72-0.85) for the entire population after adjusting for related covariates including age, education, marital history, smoking history, drinking history, diabetes, hyperlipidemia, and obesity. The trend test showed a linear association among males, females, or the entire population. Stratified analysis showed a consistent negative correlation between RMS and hypertension.

CONCLUSIONS

Higher RMS is an independent protective factor against hypertension and efforts to promote RMS may be beneficial for the prevention and management of hypertension.

Mitochondrial Dysfunction and Sarcopenic Obesity: The Role of Exercise

Sarcopenic obesity (SO) constitutes the coexistence of skeletal muscle mass loss (sarcopenia) and excess adiposity (obesity). It is mainly considered as a condition in the elderly with health-threatening impacts ranging from frailty to mortality. Mitochondrial dysfunction consists one of the basic pathophysiological mechanisms leading to the development of SO and its consequences. Indirect indicators of mitochondrial function, such as VO2max and exercise capacity, have been demonstrated to be negatively affected in individuals with SO, while the positive effect of exercise on mitochondrial function has been widely proved; thus, in this review, we aimed at investigating the effects of endurance, resistance, and concurrent exercise training on indexes of mitochondrial dysfunction in SO patients. The results of the clinical trials evaluated reveal positive effects of chronic exercise on VO2max and physical capacity, as well as mitochondrial biogenesis and activity. It has been concluded that utilizing a systematic exercise training program that includes both aerobic and strength exercises can be an effective strategy for managing SO and promoting overall health in these patients.

Impact of physical activity levels on the ability to maintain static trunk posture in older adults

PROPOSE

to assess the impact of physical activity (PA) levels on sitting posture in the older adults.

METHODS

One hundred and twenty individuals were divided into three groups according their PA levels: vigorous group (VG); moderate group (MG); low group (LG). The ability to maintain static trunk posture in sitting position as assessed based on the cervical angle (CA) and thoracic angle (TA) was measured.

RESULTS

There were no significant differences between measurements in CA for the VG. However, LG and MG participants exhibited a significant decrease in CA from minute 1 to 10 and from minute 2 to 10, respectively. In the thoracic region, only the MG exhibited significant differences in TA from minute 2 to 10 compared to minute 1 (p < 0.05). No significant differences were found in TA between measurements for either VG or LG.

CONCLUSIONS

PA has a high impact on the ability to maintain static trunk posture in the older adults.

Skeletal Muscle Consequences of Phosphatidylethanolamine Synthesis Deficiency

The maintenance of phospholipid homeostasis is increasingly being implicated in metabolic health. Phosphatidylethanolamine (PE) is the most abundant phospholipid on the inner leaflet of cellular membranes, and we have previously shown that mice with a heterozygous ablation of the PE synthesizing enzyme, Pcyt2 (Pcyt2+/-), develop obesity, insulin resistance, and NASH. Skeletal muscle is a major determinant of systemic energy metabolism, making it a key player in metabolic disease development. Both the total PE levels and the ratio of PE to other membrane lipids in skeletal muscle are implicated in insulin resistance; however, the underlying mechanisms and the role of Pcyt2 regulation in this association remain unclear. Here, we show how reduced phospholipid synthesis due to Pcyt2 deficiency causes Pcyt2+/- skeletal muscle dysfunction and metabolic abnormalities. Pcyt2+/- skeletal muscle exhibits damage and degeneration, with skeletal muscle cell vacuolization, disordered sarcomeres, mitochondria ultrastructure irregularities and paucity, inflammation, and fibrosis. There is intramuscular adipose tissue accumulation, and major disturbances in lipid metabolism with impaired FA mobilization and oxidation, elevated lipogenesis, and long-chain fatty acyl-CoA, diacylglycerol, and triacylglycerol accumulation. Pcyt2+/- skeletal muscle exhibits perturbed glucose metabolism with elevated glycogen content, impaired insulin signaling, and reduced glucose uptake. Together, this study lends insight into the critical role of PE homeostasis in skeletal muscle metabolism and health with broad implications on metabolic disease development.

Associations of myosteatosis with disc degeneration: A 3T magnetic resonance imaging study in individuals with impaired glycaemia

BACKGROUND

Intervertebral disc degeneration (IVDD) may be linked to dysregulations of skeletal muscle glucose metabolism and fatty alterations of muscle composition (Myosteatosis). Our aim was to evaluate the different associations of magnetic resonance imaging (MRI)-based paravertebral myosteatosis with lumbar disc degeneration in individuals with impaired glucose metabolism and normoglycaemic controls.

METHODS

In total, 304 individuals (mean age: 56.3 ± 9.1 years, 53.6% male sex, mean body mass index [BMI]: 27.6 ± 4.7 kg/m² ) from a population-based cohort study who underwent 3-Tesla whole-body chemical-shift-encoded (six echo times) and T2-weighted single-shot-fast-spin-echo MRI were included. Lumbar disc degeneration was assessed at motion segments L1 to L5, categorized according to the Pfirrmann score and defined as Pfirrmann grade > 2 and/or disc bulging/herniation on at least one segment. Fat content of the autochthonous back muscles and the quadratus lumborum muscle was quantified as proton density fat fraction (PDFF_muscle ). Logistic regression models adjusted for age, sex, BMI and regular physical activity were calculated to evaluate the association between PDFF_muscle and outcome IVDD.

RESULTS

The overall prevalence of IVDD was 79.6%. There was no significant difference in the prevalence or severity distribution of IVDD between participants with or without impaired glucose metabolism (77.7% vs. 80.7%, P = 0.63 and P = 0.71, respectively). PDFF_muscle was significantly and positively associated with an increased risk for the presence of IVDD in participants with impaired glycaemia when adjusted for age, sex and BMI (PDFF_{autochthonous back muscles} : odds ratio [OR] 2.16, 95% confidence interval [CI] [1.09, 4.3], P = 0.03; PDFF_{quadratus lumborum} : OR 2.01, 95% CI [1.04, 3.85], P = 0.04). After further adjustment for regular physical activity, the results attenuated, albeit approaching statistical significance (PDFF_{autochthonous back muscles} : OR 1.97, 95% CI [0.97, 3.99], P = 0.06; PDFF_{quadratus lumborum} : OR 1.86, 95% CI [0.92, 3.76], P = 0.09). No significant associations were shown in healthy controls (PDFF_{autochthonous back muscles} : OR 0.62, 95% CI [0.34, 1.14], P = 0.13; PDFF_{quadratus lumborum} : OR 1.06, 95% CI [0.6, 1.89], P = 0.83).

CONCLUSIONS

Paravertebral myosteatosis is positively associated with intervertebral disc disease in individuals with impaired glucose metabolism, independent of age, sex and BMI. Regular physical activity may confound these associations. Longitudinal studies will help to better understand the pathophysiological role of skeletal muscle in those with concomitant disturbed glucose haemostasis and intervertebral disc disease, as well as possible underlying causal relationships.

Association of myosteatosis with treatment response and survival in patients with hepatocellular carcinoma undergoing chemoembolization: a retrospective cohort study

Patients with hepatocellular carcinoma (HCC) have poor prognosis and have frequent treatment-related toxicities resulting in cancer-associated cachexia. This study aimed to determine the association of myosteatosis and sarcopenia on mortality in patients with HCC treated with transarterial chemoembolization (TACE). Six hundred and eleven patients diagnosed with HCC and underwent TACE at a tertiary care center between 2008 and 2019 were included. Body composition was assessed using axial CT slices at level L3 to calculate the skeletal muscle density for myosteatosis and skeletal muscle index for sarcopenia. The primary outcome was overall survival while the secondary outcome was TACE response. Patients with myosteatosis had a poorer TACE response than patients without myosteatosis (56.12% vs. 68.72%, adjusted odds ratio [OR] 0.49, 95% confidence interval [CI] 0.34-0.72). The rate of TACE response in patients with sarcopenia was not different from those without sarcopenia (60.91% vs. 65.22%, adjusted OR 0.79, 95% CI 0.55-1.13). Patients with myosteatosis had shorter overall survival than without myosteatosis (15.9 vs. 27.1 months, P < 0.001). In the multivariable Cox regression analysis, patients with myosteatosis or sarcopenia had higher risk of all-cause mortality than their counterparts (adjusted hazard ratio [HR] for myosteatosis versus no myosteatosis 1.66, 95% CI 1.37-2.01, adjusted HR for sarcopenia versus no sarcopenia 1.26, 95% CI 1.04-1.52). Patients with both myosteatosis and sarcopenia had the highest 7 year mortality rate at 94.45%, while patients with neither condition had the lowest mortality rate at 83.31%. The presence of myosteatosis was significantly associated with poor TACE response and reduced survival. Identifying patients with myosteatosis prior to TACE could allow for early interventions to preserve muscle quality and might improve prognosis in HCC patients.

Thigh and Calf Myosteatosis are Strongly Associated with Muscle and Physical Function in African Caribbean Men

BACKGROUND

African Caribbeans have higher levels of myosteatosis than other populations; however, little is known about the impact of myosteatosis on physical function in African Caribbeans. Herein, we examined the association between regional myosteatosis of the calf, thigh, and abdomen versus physical function in 850 African-Ancestry men aged 64.2 ± 8.9 (range 50-95) living on the Caribbean Island of Tobago.

METHODS

Myosteatosis was measured using computed tomography and included intermuscular adipose tissue (IMAT) and muscle density levels of the thigh, calf, psoas, and paraspinous muscles. Outcomes included grip strength, time to complete 5 chair-rises, and 4-meter gait speed. Associations were quantified using separate linear models for each myosteatosis depot and were adjusted for age, height, demographics, physical activity, and chronic diseases. Beta coefficients were presented per standard deviation of each myosteatosis depot.

RESULTS

Higher thigh IMAT was the only IMAT depot significantly associated with weaker grip strength (β = -1.3 ± 0.43 kg, p = .003). However, lower muscle density of all 4 muscle groups was associated with weaker grip strength (all p < .05). Calf and thigh myosteatosis (IMAT and muscle density) were significantly associated with both worse chair rise time and gait speed (all p < .05), whereas psoas IMAT and paraspinous muscle density were associated with gait speed.

CONCLUSION

Myosteatosis of the calf and thigh-but not the abdomen-were strongly associated with grip strength and performance measures of physical function in African Caribbean men. However, posterior abdominal myosteatosis may have some utility when abdominal images are all that are available.

Descriptive Epidemiology of Cardiorespiratory Fitness in UK Adults: The Fenland Study

INTRODUCTION

Cardiorespiratory fitness (CRF) is rarely measured in population studies. Most studies of CRF do not examine differences by population subgroups or seasonal trends. We examined how estimated CRF levels vary by anthropometric, sociodemographic, and behavioral characteristics in a population-based cohort of UK adults (the Fenland Study).

METHODS

We used a validated submaximal exercise test to obtain CRF estimates (CRF estimated ) in 5976 women and 5316 men, residing in the East of England. CRF estimated was defined as estimated maximal oxygen consumption per kilogram total body mass (V̇O 2 max tbm ) and fat-free mass (V̇O 2 max ffm ). Descriptive statistics were computed across anthropometric and sociodemographic characteristics, and across the year. Progressive multivariable analyses were performed to examine associations with physical activity energy expenditure (PAEE) and body mass index (BMI).

RESULTS

Mean ± SD V̇O 2 max tbm was lower in women (35.2 ± 7.5 mL·min -1 ·kg -1 ) than men (41.7 ± 7.3 mL·min -1 ·kg -1 ) but V̇O 2 max ffm was similar (women: 59.2 ± 11.6 mL·min -1 ·kg -1 ; men: 62.0 ± 10.3 mL·min -1 ·kg -1 ). CRF estimated was inversely associated with age but not after adjustment for PAEE. People in more physically demanding jobs were fitter compared with those in sedentary jobs, but this association was attenuated in women and reversed in men after adjustment for total PAEE. Physical activity energy expenditure and BMI were positively associated with CRF estimated at all levels of adjustment when expressed relative to fat-free mass. CRF estimated was 4% higher in summer than in winter among women, but did not differ by season among men.

CONCLUSIONS

CRF estimated was inversely associated with age but less steeply than anticipated, suggesting older generations are comparatively fitter than younger generations. Physical activity energy expenditure and BMI were stronger determinants of the variance in CRF estimated than other characteristic including age. This emphasizes the importance of modifiable physical activity behaviors in public health interventions.

The impact of myosteatosis on outcomes following surgery for gastrointestinal malignancy: a meta-analysis

INTRODUCTION

The aim of this review was to evaluate the impact of preoperative myosteatosis on long-term outcomes following surgery for gastrointestinal malignancy.

METHODS

We conducted a systematic search of the electronic information sources, including PubMed MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL and AMED. Studies were included if they reported the impact of preoperatively defined myosteatosis, or a similar term, on long-term survival outcomes following surgery for gastrointestinal malignancy. A subgroup analysis was performed for those studies reporting outcomes for colorectal cancer patients only.

FINDINGS

Thirty-nine full-text articles were reviewed for inclusion, with 19 being retained after the inclusion criteria were applied. The total number of included patients across all studies was 14,481. Patients with myosteatosis had significantly poorer overall survival, according to univariate (hazard ratio (HR) 1.82, 95% confidence interval (CI) 1.67-1.99) and multivariable (HR 1.66, 95% CI 1.49-1.86) analysis. This was also demonstrated for cancer-specific survival (univariate HR 1.62, 95% CI 1.18-2.22; multivariable HR 1.73, 95% CI 1.48-2.03) and recurrence-free survival (univariate HR 1.28, 95% CI 1.10-1.48; multivariable HR 1.38, 95% CI 1.07-1.77).

CONCLUSIONS

This meta-analysis demonstrates that patients with preoperative myosteatosis have poorer long-term survival outcomes following surgery for gastrointestinal malignancy. Therefore, myosteatosis should be used for preoperative optimisation and as a prognostic tool before surgery. More standardised definitions of myosteatosis and further cohort studies of patients with non-colorectal malignancies are required.

Myosteatosis, but not Sarcopenia, Predisposes NAFLD Subjects to Early Steatohepatitis and Fibrosis Progression

BACKGROUND & AIMS

Sarcopenia and myosteatosis are associated with advanced nonalcoholic fatty liver disease (NAFLD). However, muscle alterations in early stage NAFLD remain unclear.

METHODS

Patients with nonalcoholic fatty liver (NAFL) or early nonalcoholic steatohepatitis (NASH) without significant fibrosis were selected from a prospective biopsy-proven NAFLD cohort (N = 338). The skeletal muscle index and mean muscle attenuation (MA) were measured using abdominal fat computed tomography at the third lumbar vertebra level. Severe myosteatosis was defined as the lowest quartile of sex-stratified MA values.

RESULTS

Patients with early NASH (n = 87) had lower MA (45.61 ± 6.45 vs 47.48 ± 5.85 HU; P = .028) than patients with NAFL (n = 251) but a similar skeletal muscle index. Patients with more severe lobular inflammation and hepatocellular ballooning had lower MA (P = .003 and P = .041, respectively). The severe myosteatosis prevalence was higher in early NASH than in NAFL (33.3% vs 21.1%; P = .029). Patients with severe myosteatosis were more likely to have early NASH in multivariable analysis adjusted for age, sex, and metabolic factors (odds ratio, 2.45; 95% confidence interval (CI), 1.24-4.86), which was maintained after adjustment for visceral fat amount (odds ratio, 2.44; 95% CI, 1.22-4.89). During a median 29-month follow-up, 170 patients underwent repeated transient elastography. Fibrosis progression-an increase in liver stiffness measurement >2 kPa or second liver stiffness measurement ≥7 kPa-was found in 28 and 31 individuals. Severe myosteatosis was significantly associated with fibrosis progression after adjustment for various confounders (hazard ratio, 2.49; 95% CI, 1.15-5.40 and hazard ratio, 2.09; 95% CI, 1.01-4.34 for different fibrosis progression definitions).

CONCLUSIONS

Severe myosteatosis is significantly associated with early NASH and fibrosis progression in early stage NAFLD.

Prevalence of Sarcopenia and Impact on Survival in Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumours

Sarcopenia in patients with cancer is associated with adverse outcomes such as shorter survival. However, there exists little evidence regarding the prevalence of sarcopenia in patients with metastatic gastroenteropancreatic neuroendocrine tumours (GEP-NETs). Patients with a histologically confirmed newly diagnosed metastatic GEP-NET between 2006 and 2018, CT scan, and anthropometric data at diagnosis were included in this study. CT scans were analysed for the presence of sarcopenia and correlated with overall survival (OS). In total, 183 patients, 87 male (48%), with a median age of 62 years (IQR 52-68 years), were included. In 44 patients (24%), there was a pancreas NET, and in 136 patients, there was a small bowel NET (74%). Sarcopenia was present in 128 patients (69%) and unrelated to BMI (median 25.1). There were significant survival differences between patients with pancreatic and small bowel NETs at 86 vs. 141 months, respectively (p = 0.04). For patients with pancreatic NETs, the presence of sarcopenia was independently associated with shorter OS (HR 3.79 95% CI 1.1-13.03, p-value 0.035). A high prevalence of sarcopenia at the time of diagnosis of a metastatic GEP-NET was seen and associated with worse OS in patients with pancreatic NETs. Further research should focus on how to reverse sarcopenia and its impact on OS and/or quality of life.

Albumin-myosteatosis gauge as a novel prognostic risk factor in patients with non-metastatic colorectal cancer

BACKGROUND

Myosteatosis and systemic inflammation are well-known prognostic factors in patients with colorectal cancer (CRC). The serum albumin level is a reflection of malnutrition and systemic inflammation, which in turn plays a key role in the development of myosteatosis. However, few studies have been conducted on these synergistic effects. This study aimed to examine the individual and synergistic effects of different prognostic markers related to skeletal muscle quality and serum albumin levels in patients with CRC.

METHODS

This study enrolled patients with stage I-III CRC who underwent surgical resection between July 2006 and February 2014. Skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD) were calculated using computed tomography at the L3 level obtained within 2 months prior to surgery. The albumin-myosteatosis gauge (AMG) was defined as SMD × albumin. Patients were divided into sex-specific quartiles (G1 to G4) according to the AMG, and analysis of variance for continuous variables and chi-square test for categorical variables were used to compare variables among quartiles. Cox proportional hazard models were constructed and integrated receiver operating characteristic curve (iAUC) analysis was used to compare the prognostic performance of SMD, albumin and AMG.

RESULTS

Among the 906 participants, the median (interquartile) age was 64 (55-72) years, and 365 (40.3%) were female. AMG was significantly correlated with the occurrence of complications, albumin level, SMI and SMD (all P < 0.001). Overall survival (OS) differed significantly according to the AMG group, with 5-year OS for G1-G4 being 73.4%, 86.2%, 91.1% and 95.5%, respectively (P < 0.0001). Although SMI, SMD, albumin and AMG were all significant individual prognostic markers of OS in the univariable analysis, AMG remained the only independent prognostic factor in the multivariable analysis (G1 vs. G2, P = 0.045, G1 vs. G3, P = 0.005, G1 vs. G4, P < 0.001, respectively). The iAUC value of AMG [0.681, 95% confidence interval (CI) = 0.638-0.723] was superior to that of SMD (0.610, 95% CI = 0.566-0.654) (bootstrap iAUC mean difference = 0.071, 95% CI = 0.034-0.106), SMI (0.551, 95% CI = 0.511-0.594) (bootstrap iAUC mean difference = 0.129, 95% CI = 0.076-0.181) and albumin (0.627, 95% CI = 0.585-0.668) (bootstrap iAUC mean difference = 0.053, 95% CI = 0.010-0.098).

CONCLUSIONS

In patients with stage I-III CRC, AMG is a meaningful predictor of survival, with superior prognostic value compared to SMI, SMD or albumin alone. Further studies are needed to determine their significance in different ethnic groups.

Association between hypertension and myosteatosis evaluated by abdominal computed tomography

Few studies have examined the relationship between myosteatosis and hypertension, and no studies have enrolled an Asian population. Existing studies also found discordant results, possibly due to the use of conventional myosteatosis indices that are not sufficiently reliable and representative. Therefore, we investigated the association between myosteatosis and hypertension in Asian individuals using novel, objective computed tomography (CT) markers. The total abdominal muscle area (TAMA) was determined from abdominal CT scans taken at the L3 level. Based on the mean CT attenuation, the TAMA was divided into intramuscular adipose tissue and skeletal muscle area (SMA), which was further segmented into normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA). Among SMA/body mass index (BMI), NAMA/BMI, LAMA/BMI, and the NAMA/TAMA index, NAMA/BMI was chosen through receiver operating characteristic curves as the best predictive marker for hypertension. The hypertension risk for each quartile of NAMA/BMI was calculated by logistic regression analysis. Among the 19,766 participants, 40.3% of men and 23.8% of women had hypertension. People with hypertension showed unhealthier myosteatosis profiles than normotensive controls. Similarly, a lower NAMA/BMI was significantly associated with a greater hypertension risk. The lowest quartile group of NAMA/BMI exhibited 2.3- and 2.6-fold higher risks of hypertension than the highest quartile in men and women, respectively. In conclusion, advanced myosteatosis assessed by abdominal CT was significantly correlated with a higher risk of hypertension. Improving myosteatosis may be a new approach for preventing cardiovascular diseases, including hypertension. Advanced myosteatosis measured by abdominal CT taken at the L3 level was significantly correlated with a higher risk of hypertension even after adjusting for health behaviors, intake of lipid-lowering drugs, plasma lipid levels, and other ectopic fat distribution.

Intramuscular Adipose Tissue Content as a Predictor of Incisional Hernia after Hepatic Resection

BACKGROUND

Incisional hernia (IH) is a common surgical complication, with an incidence of 6-31% following major abdominal surgery. This study aimed to investigate the impact of intramuscular adipose tissue content (IMAC) on the incidence of IH in patients who underwent hepatic resection.

METHODS

Data of 205 patients who underwent open hepatic resection between 2007 and 2019 at Ehime University Hospital were retrospectively analyzed. Patient characteristics, perioperative findings, and body composition were compared between patients with IH and those without IH. The quantity and quality of skeletal muscle, calculated as skeletal muscle index and IMAC, were evaluated using preoperative computerized tomography images.

RESULTS

Forty (19.5%) patients were diagnosed with IH. The cumulative incidence rates were 15.6% at 1 year and 19.6% at 3 years. On univariate analysis, body mass index, areas of subcutaneous and visceral fat, and IMAC were significantly higher in the IH group than in the non-IH group (p = 0.0023, 0.0070, 0.0047, and 0.0080, respectively). No significant difference in skeletal muscle index was found between the groups (p = 0.3548). The incidence of diabetes mellitus, intraoperative transfusion, and postoperative wound infection was significantly higher in the IH group than in the non-IH group (p = 0.0361, 0.0078, and 0.0299, respectively). On multivariate analysis, a high IMAC and wound infection were independent risk factors for IH (adjusted odds ratio, 2.83 and 4.52, respectively; p = 0.0152 and 0.0164, respectively).

CONCLUSION

IMAC can predict the incidence of IH in patients undergoing hepatic resection.

Sarcopenia in the Cirrhotic Patient: Current Knowledge and Future Directions

Cirrhosis predisposes to abnormalities in energy, hormonal, and immunological homeostasis. Disturbances in these metabolic processes create susceptibility to sarcopenia or pathological muscle wasting. Sarcopenia is prevalent in cirrhosis and its presence portends significant adverse outcomes including the length of hospital stay, infectious complications, and mortality. This highlights the importance of identification of at-risk individuals with early nutritional, therapeutic and physical therapy intervention. This manuscript summarizes literature relevant to sarcopenia in cirrhosis, describes current knowledge, and elucidates possible future directions.

Associations of intermuscular adipose tissue and total muscle wasting score in PG-SGA with low muscle radiodensity and mass in nonmetastatic colorectal cancer: A two-center cohort study

Backgrounds

The patient-generated subjective global assessment (PG-SGA) is one of the screening criteria for malnutrition, the skeletal muscle radiodensity (SMD) and skeletal muscle mass index (SMI) are associated with survival in colorectal cancer patients. Body composition parameters can be easily assessed; however, few studies have examined the association between total muscle wasting scores in PG-SGA and body composition parameters and two muscle abnormalities.

Methods

This cohort study included 1,637 stage I-III CRC patients from 2 clinical centers in China, who were enrolled in the training cohort (n = 1,005) and validation cohort (n = 632). Baseline data were collected prospectively from patients including age, BMI, staging, gait speed, hand grip strength (HGS), peak expiratory flow (PEF), neutrophil-lymphocyte ratio (NLR), intermuscular adipose tissue (IMAT), visceral fat area (VFA) and total muscle wasting score in PG-SGA. Relevant risk factors were subjected to logistic regression analysis and Cox regression analysis to identify characteristics associated with muscle abnormalities and survival. Based on the logistic model results, normograms were established to predict muscle abnormalities, and its discrimination and calibration were assessed using the receiver operating characteristic (ROC) curve and calibration curve. The Kaplan-Meier curves were used to assess the survival of colorectal cancer patients with malnutrition or sarcopenia in an inflammatory state (assessed by NLR).

Results

The mean age of all participants was 57.7 ± 10.6 years (56.9% males) and the prevalence of low SMD and low SMI was 32.2 and 39.5%, respectively. Low SMD rate was significantly associated with age, TNM stage, BMI, IMAT, walking speed, total muscle wasting score and NRS2002 score by logistic regression analysis (p &lt; 0.05). Low SMI rate was significantly correlated with age, NLR, BMI, PEF, handgrip strength, calf circumference, walking speed, total muscle wasting score and NRS2002 score (p &lt; 0.05). The AUCs of the diagnostic nomograms were 0.859 (95% CI, 0.831–0.886) for low SMD and 0.843 (95% CI, 0.813–0.871) for low SMI in the validation cohort. We also found that patients with colorectal cancer with malnutrition or sarcopenia had a worse prognosis when NLR ≥3.5.

Conclusion

Muscle abnormalities and malnutrition are strongly associated with mortality in patients with non-metastatic colorectal cancer. Early identification and intervention of the associated risk factors may offer new ways to improve patient prognosis.

Prognostic value of myosteatosis and sarcopenia for elderly patients with colorectal cancer: A large-scale double-center study

BACKGROUND

Myosteatosis and sarcopenia are forms of muscle depletion that impair the normal physiological function of elderly patients, resulting in a worse prognosis. This study aimed to evaluate the prognostic value of sarcopenia and myosteatosis on postoperative outcomes in elderly patients with colorectal cancer.

METHODS

From February 2015 to March 2021, a total of 921 elderly patients who underwent curative surgeries for colorectal cancer at 2 centers were enrolled and grouped by the presence of either myosteatosis or sarcopenia. Clinicopathological characteristics and postoperative outcomes were compared between the 2 groups. The independent risk factors for complications and overall survival were evaluated.

RESULTS

Patients with myosteatosis had higher incidences of total and surgical complications, longer surgical duration, lower numbers of lymph nodes harvested, and longer postoperative hospital stays. Patients with sarcopenia had higher incidences of total complications, medical complications, and shorter surgical durations. Both conditions had adverse effects on overall survival and disease-free survival. Overweight status (P = .004), hypoalbuminemia (P < .001), myosteatosis, (P = .029) and sarcopenia (P = .017) were independent risk factors for total complications. Hypoalbuminemia (P = .035), myosteatosis (P = .003), sarcopenia (P = .027), and tumor-nodes-metastasis stage (≥Ⅲ; P < .001) were independent negative prognostic factors for overall survival.

CONCLUSION

Myosteatosis and sarcopenia have different characteristics and are associated with poor prognoses in elderly patients with colorectal cancer. Myosteatosis occurs more frequently. Early diagnosis and intervention for myosteatosis should be included in preoperative management, which may improve prognosis in elderly patients.

The Impact of Myosteatosis Percentage on Short-Term Mortality in Patients with Septic Shock

The impact of myosteatosis on septic patients has not been fully revealed. The aim of the study was to evaluate the impact of the myosteatosis area and percentage on the 28-day mortality in patients with septic shock. We conducted a single center, retrospective study from a prospectively collected registry of adult patients with septic shock who presented to the emergency department and performed abdominal computed tomography (CT) from May 2016 to May 2020. The myosteatosis area defined as the sum of low attenuation muscle area and intramuscular adipose tissue at the level of the third lumbar vertebra was measured by CT. Myosteatosis percentages were calculated by dividing the myosteatosis area by the total abdominal muscle area. Of the 896 patients, 28-day mortality was 16.3%, and the abnormal myosteatosis area was commonly detected (81.7%). Among variables of body compositions, non-survivors had relatively lower normal attenuation muscle area, higher low attenuation muscle area, and higher myosteatosis area and percentage than that of survivors. Trends of myosteatosis according to age group were different between the male and female groups. In subgroup analysis with male patients, the multivariate model showed that the myosteatosis percentage (adjusted OR 1.02 [95% CI 1.01–1.03]) was an independent risk factor for 28-day mortality. However, this association was not evident in the female group. Myosteatosis was common and high myosteatosis percentage was associated with short-term mortality in patients with septic shock. Our results implied that abnormal fatty disposition in muscle could impact on increased mortality, and this effect was more prominent in male patients.

Impact of Baseline Muscle Mass and Myosteatosis on the Development of Early Toxicity During First-Line Chemotherapy in Patients With Initially Metastatic Pancreatic Cancer

Objectives

Although chemotherapy is the only treatment option for metastatic pancreatic cancer (PDAC), patients frequently encounter adverse events during chemotherapy leading deterioration of patients’ quality of life and treatment interruption. We evaluated the role of baseline CT-assessed body composition in predicting early toxicity during first cycle of the first-line chemotherapy in patients with metastatic PDAC.

Methods

This retrospective study included 636 patients with initially metastatic PDAC who underwent first-line chemotherapy from January 2009 to December 2019. Chemotherapy regimen, baseline laboratory data, and body composition parameters acquired from baseline CT were obtained. The skeletal muscle index (SMI) was used to identify patients with a low muscle mass (SMI &lt; 41 cm2/m2 for women, and &lt; 43 cm2/m2 [body mass index &lt; 25 cm/kg2] or &lt; 53 cm2/m2 [body mass index ≥ 25 cm/kg2] for men), and myosteatosis was defined as low-attenuated muscle area divided by skeletal muscle area (LAMA/SMA index) ≥ 20%. Univariate and multivariable binary logistic regression analyses were performed using bootstrapping with 500 interactions to identify predictors of grade 3–4 toxicity and any treatment-modifying toxicity which led to a dose reduction, delayed administration, drug skip or discontinuation.

Results

During the first cycle of the first-line chemotherapy, grade 3–4 toxicity and treatment-modifying toxicity occurred in 160 patients (25.2%) and in 247 patients (38.8%), respectively. The presence of both low muscle mass and myosteatosis was significantly associated with the occurrence of both grade 3-4 toxicity (odd ratio [OR], 1.73; 95% confidence interval [CI], 1.14–2.63) and treatment-modifying toxicity (OR, 1.83; 95% CI, 1.26–2.66) whereas low muscle mass alone did not.

Conclusions

The presence of both low muscle mass and myosteatosis assessed on baseline CT may be used to predict early chemotherapy-related toxicity in patients with metastatic PDAC.

Associations of muscle mass and grip strength with severe NAFLD: A prospective study of 333,295 UK Biobank participants

BACKGROUND & AIMS

Cross-sectional studies have reported that lower muscle mass and strength are risk factors for non-alcoholic fatty liver disease (NAFLD). However, the evidence from prospective studies is limited. This study examined both the strength and pattern of the associations between these 2 physical capability markers and severe NAFLD using data from the UK Biobank study.

METHODS

A total of 333,295 participants were included in this prospective study. Grip strength was measured using a Jamar J00105 hydraulic hand dynamometer, and the Janssen equation was used to estimate skeletal muscle mass by bioelectrical impedance. Muscle mass was adjusted for body weight and all exposures were sex-standardised. Associations of muscle mass and strength with severe NAFLD (defined as hospital admission or death) were first investigated by tertile of each exposure using Cox proportional hazard models. Non-linear associations were investigated using penalised cubic splines fitted in the Cox proportional hazard models.

RESULTS

After a median follow-up of 10 years (IQR 9.3 to 10.7 years), 3,311 individuals had severe NAFLD (3,277 hospitalisations and 34 deaths). Compared with the lowest tertile of muscle mass, the risk of severe NAFLD was lower in the middle (hazard ratio 0.76; 95% CI 0.70-0.83) and the highest tertile (hazard ratio 0.46; 95% CI 0.40-0.52). Tertiles of grip strength showed a similar pattern. Non-linearity was only identified for muscle mass (p <0.001). Being on the lower tertile of grip strength and muscle mass accounted for 17.7% and 33.1% of severe NAFLD cases, respectively.

CONCLUSIONS

Lower muscle mass and grip strength were associated with higher risk of developing severe NAFLD. Interventions to improve physical capability may be protective, but this needs to be investigated in appropriately designed trials.

LAY SUMMARY

Lower muscle mass - both quantity and quality - were associated with a higher risk of severe non-alcoholic fatty liver disease. Therefore, improving muscle mass might be a protective factor against this increasing public health problem.

Skeletal Muscle Pathological Fat Infiltration (Myosteatosis) Is Associated with Higher Mortality in Patients with Cirrhosis

Myosteatosis (pathological fat accumulation in muscle) is defined by lower mean skeletal muscle radiodensity in CT. We aimed to determine the optimal cut-offs for myosteatosis in a cohort of 855 patients with cirrhosis. CT images were used to determine the skeletal muscle radiodensity expressed as Hounsfield Unit (HU). Patients with muscle radiodensity values below the lowest tertile were considered to have myosteatosis. Competing-risk analysis was performed to determine associations between muscle radiodensity and pre-transplant mortality. Muscle radiodensity less than 33 and 28 HU in males and females, respectively, were used as cut-offs to identify myosteatosis. In the univariate analysis, cirrhosis etiology, MELD score, refractory ascites, variceal bleeding, hepatic encephalopathy, sarcopenia and myosteatosis were predictors of mortality. Myosteatosis association with mortality remained significant after adjusting for confounding factors (sHR 1.47, 95% CI 1.17−1.84, p = 0.001). Patients with concurrent presence of myosteatosis and sarcopenia constituted 17% of the patient population. The cumulative incidence of mortality was the highest in patients with concomitant sarcopenia and myosteatosis (sHR 2.22, 95% CI 1.64−3.00, p < 0.001). In conclusion, myosteatosis is common in patients with cirrhosis and is associated with increased mortality. The concomitant presence of myosteatosis and sarcopenia is associated with worse outcomes.

Myosteatosis in Cirrhosis: A Review of Diagnosis, Pathophysiological Mechanisms and Potential Interventions

Myosteatosis, or pathological excess fat accumulation in muscle, has been widely defined as a lower mean skeletal muscle radiodensity on computed tomography (CT). It is reported in more than half of patients with cirrhosis, and preliminary studies have shown a possible association with reduced survival and increased risk of portal hypertension complications. Despite the clinical implications in cirrhosis, a standardized definition for myosteatosis has not yet been established. Currently, little data exist on the mechanisms by which excess lipid accumulates within the muscle in individuals with cirrhosis. Hyperammonemia may play an important role in the pathophysiology of myosteatosis in this setting. Insulin resistance, impaired mitochondrial oxidative phosphorylation, diminished lipid oxidation in muscle and age-related differentiation of muscle stem cells into adipocytes have been also been suggested as potential mechanisms contributing to myosteatosis. The metabolic consequence of ammonia-lowering treatments and omega-3 polyunsaturated fatty acids in reversing myosteatosis in cirrhosis remains uncertain. Factors including the population of interest, design and sample size, single/combined treatment, dosing and duration of treatment are important considerations for future trials aiming to prevent or treat myosteatosis in individuals with cirrhosis.

The Impact and Clinical Prediction of Hyperglycemia During Parenteral Nutrition for Nondiabetic Patients After Gastrectomy for Gastric Cancer

Background and Purpose

Hyperglycemia (HG) is associated with increased postoperative complications. This study aims to evaluate the effect of HG during supplemental parenteral nutrition (SPN) on short-term prognosis in non-diabetic patients undergoing gastrectomy for cancer and to analyse the risk factors and prevention methods for HG.

Methods

A total of 359 patients were divided into three groups according to blood glucose (BG) during SPN: normoglycemic patients ( ≤ 125 mg/dL), mild HG (125~200 mg/dL), and severe HG (>200 mg/dL). The effect of BG on postoperative short-term outcomes was analyzed. Multivariate regression was performed to investigate influencing factors for severe HG. The safety and efficacy of insulin addition to total nutrient admixture (TNA) for the prevention and management of HG were assessed by propensity score matching (PSM). In addition, regression analysis was performed in the noninsulin group to investigate the predictive factors of severe HG, and a nomogram was plotted.

Results

The postoperative complication rate was 18.9%, but it was significantly higher in patients with severe HG than in mild HG and normoglycemic patients (25.2, 15.0, and 10.0%, respectively, p < 0.05). Multivariate logistic regression analysis showed that anemia, myosteatosis, higher postoperative capillary blood glucose (CBG) before TNA infusion, and insulin in the TNA were independent influencing factors for severe HG. Based on the above factors, 75 pairs of patients (insulin group and non-insulin group) with comparable baseline data were successfully matched by PSM. The HG incidence and the glycemic fluctuation were significantly improved through 1 U insulin/6 g glucose (1/6 scheme) to TNA. A nomogram containing hemoglobin, skeletal muscle radiodensity, pre-SPN CBG, and pTNM stage with good predictive efficacy (C-index: 0.750) was constructed based on the noninsulin group.

Conclusion

Poor postoperative glycemic control was related to worse outcomes in non-diabetic patients undergoing gastrectomy for cancer. Pre-operative anemia, myosteatosis, and high postoperative CBG before TNA infusion are risk factors for severe HG. Insulin in TNA can improve the blood glucose control of patients. Our proposed nomogram rendered an individualized predictive tool for HG during SPN, which helps screen high-risk patients requiring insulin therapy. Future studies with larger samples are needed to develop a complete insulin application protocol for SPN.

Aerobic fitness and muscle density play a vital role in postoperative complications in colorectal cancer surgery

Background and Objectives

To assess the association of preoperative aerobic fitness and body composition variables with a patient's resilience to the development and impact of postoperative complications after elective colorectal cancer (CRC) surgery.

Methods

Preoperative aerobic fitness was assessed by steep ramp test performance. Preoperative body composition was assessed by muscle mass and density determined from preoperative computed tomography scan analysis at the L3‐level. Complication development and severity was graded according to Clavien‐Dindo. Complication impact was assessed by the time to recovery of physical functioning after complications. Multivariable logistic regression analyses adjusted for age, sex, comorbidities and tumour location was performed.

Results

Of 238 included patients, 96 (40.3%) developed postoperative complications. Better preoperative aerobic fitness decreased the likelihood to develop complications, independent of muscle mass (odds ratio [OR]: 0.55, 95% confidence interval [CI]: 0.35−0.85) or muscle density (OR: 0.57, 95% CI: 0.36−0.89). A prolonged time to recovery following complications was associated with lower preoperative muscle density (OR: 4.14, 95% CI: 1.28−13.41), independent of aerobic fitness.

Conclusions

Lower aerobic fitness increases the risk of complication development, while low muscle density seems associated with a prolonged recovery from complications. Aerobic fitness and muscle density could be valuable additives to preoperative risk assessment.

Impact of Sarcopenia and Myosteatosis in Non-Cirrhotic Stages of Liver Diseases: Similarities and Differences across Aetiologies and Possible Therapeutic Strategies

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

Sex- and region-specific associations of skeletal muscle mass with metabolic dysfunction-associated fatty liver disease

INTRODUCTION

Metabolic dysfunction-associated fatty liver disease (MAFLD) is known to be the most common chronic liver disease worldwide, and accumulating evidence suggests that skeletal muscle might play an important role in metabolic health. However, the association between skeletal muscle and MAFLD is poorly understood so far. Therefore, we aimed to evaluate the associations of skeletal muscle with MAFLD and significant fibrosis.

METHODS

A cross-sectional analysis was conducted using data obtained from the 2017-2018 US National Health and Nutrition Examination Survey. The whole-body, appendicular, and trunk skeletal muscle mass index (SMI) were assessed by dual-energy x-ray absorptiometry. MAFLD and significant fibrosis were assessed by transient elastography. Survey-weight adjusted multivariable logistic regressions were used to determine the associations. The area under the receiver operating characteristic curve (AUC) and variable importance scores from the random forest and logistic regression model were calculated to assess the predictive capability of variables and models.

RESULTS

Of the 2065 participants, those with appendicular SMI in the highest quartile were associated with a lower risk for MAFLD in both sexes (male, OR[95%CI]: 0.46 [0.25~0.84]; female, OR[95%CI]: 0.32 [0.13~0.82]), but with a significantly different scale of the associations between sexes (P _interaction = 0.037). However, females with trunk SMI in the highest quartile had an increased risk of significant fibrosis (OR[95%CI]: 7.82 [1.86~32.77]). Trunk SMI and appendicular SMI ranked the third contributor to MAFLD in random forest and logistic regression models, respectively. Taking appendicular and trunk SMI into consideration, the AUCs for MAFLD were 0.890 and 0.866 in random forest and logistic regression models, respectively.

DISCUSSION

The distribution of skeletal muscle mass differently affects MAFLD and significant fibrosis in the sex groups. Higher appendicular skeletal muscle mass was associated with a lower risk of MAFLD, while the risk of significant fibrosis in females was increased with the trunk skeletal muscle mass.

Peripheral bone structure, geometry, and strength and muscle density as derived from peripheral quantitative computed tomography and mortality among rural south Indian older adults

Multiple studies have observed a relationship of bone mineral density (BMD) measured by Dual energy X-ray absorptiometry (DXA) and mortality. However, areal BMD (aBMD) measured by DXA is an integrated measure of trabecular and cortical bone and does not measure the geometry of bone. Peripheral Quantitative Computed Tomography (pQCT) provides greater insights on bone structure, geometry and strength. To examine whether higher bone phenotypes and muscle density as measured by pQCT are associated with a lower all-cause mortality, we studied 245 men and 254 women (all age >60) recruited in the Mobility and Independent Living among Elders Study in rural south India. Cox proportional hazards models estimated hazard ratios (HR [95% Confidence Intervals]). After an average follow-up of 5.3 years, 73 men and 50 women died. Among men, trabecular volumetric bone mineral density (vBMD) of radius (HR per SD increase in parameter = 0.59 [0.43, 0.81]) and tibia (0.60[0.45, 0.81]), cortical vBMD of radius (0.61, [0.47, 0.79]) and tibia (0.62, [0.49, 0.79]), cortical thickness of radius (0.55, [0.42, 0.7]) and tibia (0.60, [0.47, 0.77]), polar strength strain index (SSIp) of tibia (0.73 [0.54, 0.98]), endosteal circumference of radius (1.63, [1.25, 2.12]) and tibia (1.54, [1.19, 1.98]) were associated with all-cause mortality. Muscle density (0.67, [0.51, 0.87]) was associated with lower mortality in men. Among women cortical vBMD of radius (0.64, [0.47, 0.87]) and tibia (0.60 [0.45, 0.79]), cortical thickness of radius (0.54, [0.37, 0.79]) and tibia (0.43, [0.30, 0.61]), SSIp of radius (0.70 [0.48,1.01]) and tibia (0.58 [0.37, 0.90]) and endosteal circumference of radius (1.33 [0.97, 1.82]) and tibia (1.83, [1.37, 2.45]) were associated with all-cause mortality. Among men, gait speed mediated the association of muscle density and mortality but there was no mediation for any bone parameters. Conclusion: pQCT bone measures and muscle density were independently associated with mortality among rural south Indian elders.

Strategies to Prevent Sarcopenia in the Aging Process: Role of Protein Intake and Exercise

Sarcopenia is one of the main issues associated with the process of aging. Characterized by muscle mass loss, it is triggered by several conditions, including sedentary habits and negative net protein balance. According to World Health Organization, it is expected a 38% increase in older individuals by 2025. Therefore, it is noteworthy to establish recommendations to prevent sarcopenia and several events and comorbidities associated with this health issue condition. In this review, we discuss the role of these factors, prevention strategies, and recommendations, with a focus on protein intake and exercise.

Computed Tomography-Derived Skeletal Muscle Radiodensity Is an Early, Sensitive Marker of Age-Related Musculoskeletal Changes in Healthy Adults

BACKGROUND

A decrease in computed tomography (CT)-derived skeletal muscle radiodensity (SMD) reflects age-related ectopic fat infiltration of muscle, compromising muscle function and metabolism. We investigated the age-related trajectory of SMD and its association with vertebral trabecular bone density in healthy adults.

METHODS

In a cohort of healthy adult kidney donors aged 19 to 69 years (n=583), skeletal muscle index (SMI, skeletal muscle area/height2), SMD, and visceral-to-subcutaneous fat (V/S) ratio were analyzed at the level of L3 from preoperative CT scans. Low bone mass was defined as an L1 trabecular Hounsfield unit (HU) <160 HU.

RESULTS

L3SMD showed constant decline from the second decade (annual change -0.38% and -0.43% in men and women), whereas the decline of L3SMI became evident only after the fourth decade of life (-0.37% and -0.18% in men and women). One HU decline in L3SMD was associated with elevated odds of low bone mass (adjusted odds ratio, 1.07; 95% confidence interval, 1.02 to 1.13; P=0.003), independent of L3SMI, age, sex, and V/S ratio, with better discriminatory ability compared to L3SMI (area under the receiver-operating characteristics curve 0.68 vs. 0.53, P<0.001). L3SMD improved the identification of low bone mass when added to age, sex, V/S ratio, and L3SMI (category-free net reclassification improvement 0.349, P<0.001; integrated discrimination improvement 0.015, P=0.0165).

CONCLUSION

L3SMD can be an early marker for age-related musculoskeletal changes showing linear decline throughout life from the second decade in healthy adults, with potential diagnostic value for individuals with low bone mass.

Association of body composition with toxicity to first-line chemotherapy and three-year survival in women with ovarian adenocarcinoma

BACKGROUND

This study aimed to evaluate the association of body composition with toxicity to first-line chemotherapy and three-year survival in women with ovarian adenocarcinoma.

METHODS

We enrolled, in a retrospective cohort, 239 women treated with carboplatin and paclitaxel between 2008 and 2017. Pretreatment computed tomography scans were used to quantify skeletal muscle index (SMI), skeletal muscle radiodensity (SMD), and subcutaneous adipose tissue index (SATI). Chemotherapy doses, related toxicities, potential drug-drug interactions (DDI), and clinical variables were collected from medical records. Outcomes were the number of adverse events ≥ grade 3 toxicity, toxicity-induced modification of treatment (TIMT), and three-year survival.

RESULTS

Average age was 56.3 years and 35.1% had myopenia. Almost 33% had TIMT and 51.3% presented any grade 3 toxicity. Potential severe DDI occurred in 48.1% of the patients and 65.1% died three years after the first treatment. The SMD and SATI below the median were independent predictors for the number of adverse events ≥ grade 3 and TIMT. Also, SMD was the only body composition parameter able to predict reduced three-year survival. The SMI was not associated with any of the outcomes.

CONCLUSION

Fewer amounts of SATI and low SMD were associated with the occurrence of toxicity to chemotherapy, and the low SMD increased the risk of death in the three years after oncologic treatment.

Cachexia Versus Sarcopenia in Clinical Characteristics and Prognostic Value After Radical Gastrectomy for Gastric Cancer: A Large-Scale Prospective Study

BACKGROUND

Sarcopenia and cachexia are two predictors of adverse clinical outcomes, but they are partly overlapping. We aimed to compare the characteristics and prognostic value of cachexia and sarcopenia in patients after gastrectomy.

METHODS

From 2014 to 2019, a total of 1215 gastric cancer patients were enrolled. Cachexia and sarcopenia were diagnosed according to the most recent consensus definitions. Baseline characteristics and clinical outcomes were compared between the two groups. Risk factors of survival were evaluated by Cox regression analysis.

RESULTS

Of all patients, 26.5% were diagnosed with cachexia and 19.8% were diagnosed with sarcopenia. Sarcopenia was more prevalent in elderly patients, while cachexia was prone to occur in patients with TMN stage III. Survival curves showed that sarcopenia had adverse effects in patients with TMN stage I and II-III, while cachexia was only associated with poor survival at stages II-III. For the entire cohort, both cachexia and sarcopenia were adverse factors for prognosis. However, for stage I patients, sarcopenia was an independent predictor for overall survival (OS) (HR = 4.939, P < 0.001) and disease-free survival (DFS) (HR = 4.256, P < 0.001), but not cachexia; for stage II-III patients, cachexia was an independent predictor for OS (HR = 1.538, P < 0.001) and DFS (HR = 1.473, P = 0.001), but not sarcopenia.

CONCLUSIONS

Sarcopenia and cachexia have different clinical characteristics and prognostic values. For patients with early stage gastric cancer, detection for sarcopenia was more meaningful than cachexia. However, the prognostic significance of cachexia exceeded sarcopenia in advanced cancer.

Quantitative Ultrasound Changes in Echotexture and Functional Parameters after a Multicomponent Training Program in Pre-Frailty Individuals: A Pilot Randomized Clinical Trial

Objective: Currently, ultrasound imaging (USI) is considered a feasible tool in the evaluation of structural and textural muscle differences due to aging. The main aim of this study was to evaluate sonographic changes in muscular structure and function after a 12-week multicomponent training program in pre-frailty individuals. Design: A prospective, randomized, clinical trial was carried out. Participants: Thirty-two pre-frailty subjects were recruited and randomly divided into a multicomponent training program group (n = 16; Multicomponent group) and a conventional care group (n = 14; Control group) with a 12-week follow up. Main outcome measures: Rectus femoris thickness, cross-sectional area (CSA), echointensity, echovariation and vastus lateralis pennation angle tests were carried out to assess the structure and echotexture, and the force-velocity (F-V) profile for muscle power and muscle strength was employed to assess the functional parameters. Results: Statistically significant differences (p < 0.05) were shown for the left rectus femoris echointensity and in the functional parameter of muscle power after a 12-week program for the multicomponent training group compared to the conventional care group. Conclusions: Pre-frailty elderly subjects showed a decrease in rectus femoris echointensity (RF-EI) and an increase in the functional parameter of muscle power after a 12-week multicomponent training program compared to the control group.

Associations Between Lipoprotein Subfractions and Area and Density of Abdominal Muscle and Intermuscular Adipose Tissue: The Multi-Ethnic Study of Atherosclerosis

Skeletal muscle quantity and quality decrease with older age, which is partly attributed to ectopic fat infiltration and has negative metabolic consequences. To inform efforts to preserve skeletal muscle with aging, a better understanding of biologic correlates of quantity and quality of muscle and intermuscular adipose tissue (IMAT) is needed. We used targeted lipidomics of lipoprotein subfractions among 947 Multi-Ethnic Study of Atherosclerosis participants to provide a detailed metabolic characterization of area and density of abdominal muscle and IMAT. Serum lipoprotein subfractions were measured at the first visit using 1H-Nuclear Magnetic Resonance spectroscopy. Muscle and IMAT area (cm2) and density (Hounsfield units) were estimated at visit 2 or 3 using computed tomography of the total abdominal, locomotion (psoas), and stabilization (paraspinal, oblique, rectus abdominis) muscles. We identified lipoprotein subfractions associated with body composition using linear regression adjusting for demographics, lifestyle, and multiple comparisons. Among 105 lipoprotein subfractions, 24 were associated with total muscle area (absolute standardized regression coefficient range: 0.07-0.10, p-values ≤ 0.002), whereas none were associated with total muscle density. When examining muscle subgroups, 25 lipoprotein subfractions were associated with stabilization muscle area, with associations strongest among the obliques. For total IMAT area, there were 27 significant associations with lipoprotein subfractions (absolute standardized regression coefficient range: 0.09-0.13, p-values ≤ 0.002). Specifically, 27 lipoprotein subfractions were associated with stabilization IMAT area, with associations strongest among the oblique and rectus abdominis muscles. For total IMAT density, there were 39 significant associations with lipoprotein subfractions (absolute standardized regression coefficient range: 0.10-0.19, p-values ≤ 0.003). Specifically, 28 and 33 lipoprotein subfractions were associated with IMAT density of locomotion and stabilization (statistically driven by obliques) muscles, respectively. Higher VLDL (cholesterol, unesterified cholesterol, phospholipids, triglycerides, and apolipoprotein B) and lower HDL (cholesterol and unesterified cholesterol) were associated with higher muscle area, higher IMAT area, and lower IMAT density. Several associations between lipoprotein subfractions and abdominal muscle area and IMAT area and density were strongest among the stabilization muscles, particularly the obliques, illustrating the importance of examining muscle groups separately. Future work is needed to determine whether the observed associations indicate a lipoprotein profile contributing to worse skeletal muscle with fat infiltration.

Arsenic Secondary Methylation Capacity Is Inversely Associated with Arsenic Exposure-Related Muscle Mass Reduction

Skeletal muscle mass reduction has been implicated in insulin resistance (IR) that promotes cardiometabolic diseases. We have previously reported that arsenic exposure increases IR concomitantly with the reduction of skeletal muscle mass among individuals exposed to arsenic. The arsenic methylation capacity is linked to the susceptibility to some arsenic exposure-related diseases. However, it remains unknown whether the arsenic methylation capacity affects the arsenic-induced reduction of muscle mass and elevation of IR. Therefore, this study examined the associations between the arsenic methylation status and skeletal muscle mass measures with regard to IR by recruiting 437 participants from low- and high-arsenic exposure areas in Bangladesh. The subjects' skeletal muscle mass was estimated by their lean body mass (LBM) and serum creatinine levels. Subjects' drinking water arsenic concentrations were positively associated with total urinary arsenic concentrations and the percentages of MMA, as well as inversely associated with the percentages of DMA and the secondary methylation index (SMI). Subjects' LBM and serum creatinine levels were positively associated with the percentage of DMA and SMI, as well as inversely associated with the percentage of MMA. HOMA-IR showed an inverse association with SMI, with a confounding effect of sex. Our results suggest that reduced secondary methylation capacity is involved in the arsenic-induced skeletal muscle loss that may be implicated in arsenic-induced IR and cardiometabolic diseases.