Skeletal Muscle Quantity Research Articles

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

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

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

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

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

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

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

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

Skeletal Muscle Quality and Quantity Affect Prognosis after Neoadjuvant Chemotherapy with a Triple Regimen of Docetaxel/Cisplatin/5-FU in Patients with Esophageal Cancer.

The purpose of this study was to identify factors associated with the prognosis after docetaxel, cisplatin, and 5-fluorouracil (DCF) neoadjuvant chemotherapy (NAC) in patients with advanced esophageal squamous cell carcinoma (ESCC) undergoing surgical resection. We retrospectively examined a total of 100 patients who received neoadjuvant DCF therapy for ESCC at our institution between 2011 and 2020. The psoas muscle index (PMI) was calculated from the psoas muscle area at the L3 vertebral level, and the intramuscular adipose tissue content (IMAC) was calculated from the mean CT value of the multifidus muscle and from four points of subcutaneous fat. The median PMI value was 6.11 cm2/m2 (range, 3.12-11.07 cm2/m2) in men and 3.65 cm2/m2 (range, 2.70-6.82 cm2/m2) in women. The median IMAC was -0.426 (range, -0.079--0.968) in men and -0.359 (range, -0.079--0.671) in women. Based on the PMI, IMAC, and other patient factors, factors associated with NAC-DCF postoperative survival were identified using multivariate Cox regression analysis. A high IMAC was significantly related to overall survival after surgery (p = 0.005, hazard ratio 2.699). A comparison of Kaplan-Meier curves showed that the 5-year survival rate was 76.5% in the low IMAC group and 42.7% in the high IMAC group (log-rank test; p = 0.001). A low IMAC was associated with good survival outcomes and was an independent prognostic factor in patients with cStage II/III ESCC who were treated with the NAC-DCF regimen and underwent surgical resection.

Role of Actin-Binding Proteins in Skeletal Myogenesis.

Maintenance of skeletal muscle quantity and quality is essential to ensure various vital functions of the body. Muscle homeostasis is regulated by multiple cytoskeletal proteins and myogenic transcriptional programs responding to endogenous and exogenous signals influencing cell structure and function. Since actin is an essential component in cytoskeleton dynamics, actin-binding proteins (ABPs) have been recognized as crucial players in skeletal muscle health and diseases. Hence, dysregulation of ABPs leads to muscle atrophy characterized by loss of mass, strength, quality, and capacity for regeneration. This comprehensive review summarizes the recent studies that have unveiled the role of ABPs in actin cytoskeletal dynamics, with a particular focus on skeletal myogenesis and diseases. This provides insight into the molecular mechanisms that regulate skeletal myogenesis via ABPs as well as research avenues to identify potential therapeutic targets. Moreover, this review explores the implications of non-coding RNAs (ncRNAs) targeting ABPs in skeletal myogenesis and disorders based on recent achievements in ncRNA research. The studies presented here will enhance our understanding of the functional significance of ABPs and mechanotransduction-derived myogenic regulatory mechanisms. Furthermore, revealing how ncRNAs regulate ABPs will allow diverse therapeutic approaches for skeletal muscle disorders to be developed.

The ethanol extract of Euphorbia hirta exhibits in vitro antidiabetic potentials by sensitization of the insulin

The objective of current investigation was to assess the mechanism of action of Euphorbia hirta for its antidiabetic properties. Materials &amp;Methods: The authenticated leaves of plant Euphorbia hirta were dried and powdered. The powdered drug was defatted with petroleum ether and subjected to ethanol extraction. The ethanol extract of Euphorbia hirta was subjected to preliminary phytochemical investigation. The glucose up takes by rat hemi-diaphragm (skeletal muscle) model was also used evaluate potentials of the ethanol extract of Euphorbia hirta to enhance utilization of the blood glucose by peripheral tissues. The overnight fasted albino rat was sacrificed and dissected to hemidiaphragm. Weighed quantity of skeletal muscle was incubated with glucose in Tyrode solution for 30 mins at 37oC and the amount of glucose utilized by the tissue was determined. Results: The ethanol extract of Euphorbia hirta significantly increased the glucose utilization by skeletal muscle which its shows potency to sensitize the insulin. Conclusion: The results of the presents investigation recommends that, one of the mechanisms of ethanol extract of Euphorbia hirta for antidiabetic activity is reduction of insulin resistance.

The use of non-invasive imaging modalities for the assessment of skeletal muscle quantity and quality in people with HIV: A narrative review.

People with HIV (PWH) are prone to mobility impairments and physical dysfunction, with the loss of skeletal muscle quantity and quality being a major contributor to the dysfunction. Assessment of skeletal muscle is an important component of care for this patient population for early intervention and treatment. The use of non-invasive imaging techniques to evaluate skeletal muscle, such as dual X-ray absorptiometry, computer tomography and magnetic resonance imaging, has increased in popularity in recent years. This narrative review synthesizes the use of these techniques and summarizes the associations between outcomes from these imaging modalities and physical function in PWH.

Motor unit firing patterns in older adults with low skeletal muscle mass

Muscular dysfunctions involving a decline in muscle strength are often induced by loss of muscle mass in older adults. Understanding neural activation in older adults in addition to muscular characteristics may be important to prevent such age-related dysfunctions. This study aimed to investigate the difference in motor unit firing patterns between community-dwelling older individuals with normal and low skeletal muscle mass. Sixty-six older adults (62–90 years) performed muscle strength and function tests. On conducting high-density surface electromyography of the vastus lateralis, individual motor unit firing properties were assessed. Individual motor units were divided into three different recruitment threshold groups and their firing rates were compared. The skeletal muscle quantity and quality were assessed using bioimpedance methods and ultrasound images. They were divided into two groups according to sarcopenia criteria: a normal group (n = 39) and presarcopenia group with low skeletal muscle mass but normal physical functions (n = 21). Skeletal muscle mass and muscle thickness were greater and echo intensity was lower in the normal group than presarcopenia group. Motor units in normal older adults fired at different rates with a hierarchy depending on their recruitment threshold, observed as a normal phenomenon. However, motor units in the presarcopenia group fired without showing the hierarchical pattern. The results suggest that older adults with low skeletal muscle mass exhibited an abnormal neural input pattern, in addition to declines in muscle quantity and quality.

Is the ECOG-PS similar to the sarcopenia status for predicting mortality in older adults with cancer? A prospective cohort study.

Sarcopenia is a muscle dysfunction that increases negative outcomes in patients with cancer. However, its diagnosis remains uncommon in clinical practice. The Eastern Cooperative Oncology Group Performance Status (ECOG-PS) is a questionnaire to assess the functional status, but it is unknown if is comparable with sarcopenia. We aimed at comparing ECOG-PS with sarcopenia to predict 12-month mortality in patients with cancer. Cohort study including older adult patients with cancer in treatment (any stage of the disease or treatment) at a reference hospital for oncological care. Socio-demographic, clinical, and anthropometric data, muscle mass, and physical function variables (handgrip strength [HGS] and gait speed [GS]) were collected. Skeletal muscle quantity and quality were assessed by computed tomography at the L3. Sarcopenia was diagnosed according to the EWGSP2. ECOG-PS and all-cause mortality were evaluated. The Cox proportional hazards model was calculated. We evaluated 159 patients (69years old, 55% males). Low performance (ECOG-PS ≥ 2) was found in 23.3%, 35.8% presented sarcopenia, and 22.0% severe sarcopenia. ECOG-PS ≥ 2 was not an independent predictor of mortality. Sarcopenia, severe sarcopenia, and probable sarcopenia has increased by 3.25 (confidence interval, CI 95% 1.55-6.80), 2.64 (CI 95% 1.23-5.67), and 2.81 (CI 95% 1.30-6.07) times the risk of mortality, respectively. Sarcopenia, but not ECOG-PS, was a predictor of mortality. Therefore, ECOG-PS was not similar to sarcopenia to predict mortality in patients with cancer.

Endurance exercise training reinforces muscular strength with improvements in mitochondrial oxidative capacity, lysosome reformation, and myogenic differentiation against doxorubicininduced skeletal muscle wasting in mice.

Doxorubicin (DOX) is a chemotherapeutic medication broadly used to treat diverse cancers. However, chronic DOX chemotherapy can cause myotoxicity and muscle atrophy. Endurance exercise (EXE) is used to prevent negative muscle excitation. Based on emerging evidence, this study investigated the challenges that occur in skeletal muscle quantity, quality, and metabolic determinants through autophagy, myogenic regulatory factors (MRF), antioxidant enzymes, and both the AMPK and AKT/mTOR pathways. Male C57BL/6J adult mice were divided into four groups after one week of acclimation: sedentary (SED) plus saline (SAL)-receiving (SED-SAL), EXE plus SAL-receiving (EXE-SAL), SED plus DOX-receiving (SED-DOX), and EXE plus DOX-receiving (EXEDOX) groups. All mice were intraperitoneally inoculated with either SAL or DOX (5 mg/kg, every 2 weeks) for 8 weeks, while a treadmill running EXE was performed. Body weight, muscle weight, and muscle strength were measured, and the red portions of the gastrocnemius muscle were excised for biochemical analysis. Chronic DOX administration deteriorated body composition by decreasing body and absolute muscle weights, whereas EXE reinforced a grip strength per body weight. Although DOX inhibited BECN1 expression, EXE enhanced CS, LC3-I, LC3-II, and LAMP levels. Moreover, DOX did not interrupt MRF functions, but EXE improved MYOD without altering SOD1 or SOD2 expression. However, neither the AMPK nor the AKT/mTOR signaling pathways were associated with either DOX-receiving or EXE training. DOX chemotherapy-induced muscle wasting is associated with autophagy dysregulation. However, long-term aerobic EXE training enhances muscular strength with an increase in mitochondrial oxidative capacity, lysosome formation, and myogenic differentiation.

Impact of the quantity and quality of the skeletal muscle on survival among patients undergoing allogeneic hematopoietic stem cell transplantation

IntroductionPoor skeletal muscle function is relatively high in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), leading to various negative health outcomes. This study aimed to investigate the relationship between the quantity and quality of skeletal muscle before transplantation and the short-to long-term survival after transplantation in patients undergoing allo-HSCT. MethodsThis retrospective cohort study included 156 patients undergoing allo-HSCT (men, 67.3 %; median age, 53 years; interquartile range, 42–61 years). The quantity and quality of the skeletal muscle were measured at the psoas major at the level of the third lumbar vertebrae using a computed tomography (CT) and were defined as psoas muscle index (PMI) and CT values (CTV), respectively. The outcome measure of this study was overall survival (OS) after allo-HSCT, and we examined the relationship between survival at three time points (6, 12, and 24 months) after transplantation, PMI, and CTV. ResultsPMI was significantly associated with survival at all time points in the crude model (P < 0.001), and a significant association was observed in the fully adjusted model (P < 0.01). CTV was significantly associated with survival at all time points in the crude model (P < 0.05), but not in the fully adjusted model (P > 0.05). ConclusionsWe found that the quantity and quality of the skeletal muscle before transplantation were significantly associated with OS at 6, 12, and 24 months after transplantation, showing a particularly robust association with quantity.

Robust Assessment of Macromolecular Fraction (MMF) in Muscle with Differing Fat Fraction Using Ultrashort Echo Time (UTE) Magnetization Transfer Modeling with Measured T1.

Magnetic resonance imaging (MRI) is widely regarded as the most comprehensive imaging modality to assess skeletal muscle quality and quantity. Magnetization transfer (MT) imaging can be used to estimate the fraction of water and macromolecular proton pools, with the latter including the myofibrillar proteins and collagen, which are related to the muscle quality and its ability to generate force. MT modeling combined with ultrashort echo time (UTE-MT modeling) may improve the evaluation of the myotendinous junction and regions with fibrotic tissues in the skeletal muscles, which possess short T2 values and higher bound-water concentration. The fat present in muscle has always been a source of concern in macromolecular fraction (MMF) calculation. This study aimed to investigate the impact of fat fraction (FF) on the estimated MMF in bovine skeletal muscle phantoms embedded in pure fat. MMF was calculated for several regions of interest (ROIs) with differing FFs using UTE-MT modeling with and without T1 measurement and B1 correction. Calculated MMF using measured T1 showed a robust trend, particularly with a negligible error (<3%) for FF < 20%. Around 5% MMF reduction occurred for FF > 30%. However, MMF estimation using a constant T1 was robust only for regions with FF < 10%. The MTR and T1 values were also robust for only FF < 10%. This study highlights the potential of the UTE-MT modeling with accurate T1 measurement for robust muscle assessment while remaining insensitive to fat infiltration up to moderate levels.

Mechanisms of sarcopenia in liver cirrhosis and the role of myokines.

Sarcopenia is a syndrome characterized by a decline in skeletal muscle quantity and/or quality, strength and performance, leading to unfortunate events, such as injurious falls or even death. It is not identical to frailty and malnutrition, even though there is a significant overlap among these syndromes. In patients with liver cirrhosis (LC), sarcopenia is classified as secondary and has been associated with increased morbidity and mortality during the pre- and post-transplantation period. It can be a result of malnutrition, hyperammonemia, low physical activity, endocrine abnormalities, accelerated starvation, metabolic disturbances, altered gut function leading to chronic inflammation, and alcohol abuse. Myokines are peptides mainly synthesized by contracting muscle and adipose tissue cells and may play a key role in the pathophysiology of sarcopenia. More than a hundred myokines have been recognized, but only a few have been investigated. They can be classified as negative regulators, such as myostatin, tumor growth factor-β, activins, growth differentiation factor-11, and positive regulators of muscle growth including follistatin, bone morphogenic proteins, and irisin. So far, only myostatin, follistatin, irisin and decorin have been studied in LC-associated sarcopenia. In this review, we focused on the mechanisms of cirrhosis-related sarcopenia and the role of myokines that have already been studied in the literature, either as markers helping in the diagnostic evaluation of sarcopenia, or as prognostic factors of survival. Standard therapeutic options to prevent or treat sarcopenia in LC are also being reported, as well as the possible therapeutic implication of myokines.

Preoperative skeletal muscle fat infiltration is a strong predictor of poorer survival in gallbladder cancer underwent surgery

Recently, a decrease in skeletal muscle, termed sarcopenia, has been reported to be associated with poorer survival of patients in several types of cancer. However, few studies have investigated the association between sarcopenia and the survival of patients with gallbladder cancer. A total of 88 patients undergoing curative resection for advanced gallbladder cancer were included in this study. The quality of skeletal muscle was assessed by the intramuscular adipose tissue content (IMAC), and the quantity of skeletal muscle was assessed by the psoas muscle index (PMI), measured on preoperative computed tomography. The optimum cutoff values for IMAC and PMI for predicting the overall survival in each sex were determined using a minimum p value approach. Clinicopathological factors, IMAC and PMI were retrospectively analyzed to identify the predictors of overall survival (OS). The cutoff values for IMAC were-0.3 in males and 0.04 in females. The numbers of patients with low IMAC and high IMAC were 42 and 46, respectively. The cutoff values for PMI were 7.3cm2/m2 in males and 5.0cm2/m2 in females. The numbers of patients with low PMI and high PMI were 22 and 66, respectively. A multivariate analysis revealed that pT stage (pT3/4, hazard ratio [HR]=6.72, p=0.004), high IMAC (HR=4.12, p<0.001), Bile duct infiltration (present, HR=2.82, p=0.046), high age (≥72 years old, HR=2.64, p=0.010), major hepatectomy (performed, HR=2.50, p=0.031) and pN1/2 (HR=2.17, p=0.010) as independent prognostic factors. IMAC was independent prognostic factor for resected advanced gallbladder cancer, so the quality of skeletal muscle more strongly predicted survival than the quantity of skeletal muscle.

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

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. 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. Forty (19.5%) patients were diagnosed with IH. The cumulative incidence rates were 15.6% at 1year and 19.6% at 3years. 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). IMAC can predict the incidence of IH in patients undergoing hepatic resection.

Progress in Research on Antitumor Drugs and Dynamic Changes in Skeletal Muscles.

Objective: To review the research progress of reltionship between antitumor drugs and the dynamic changes of the skeletal muscles during treatment phase. Background: Sarcopenia is a common disease in patients with tumors, and it has been agreed that patients with tumors and sarcopenia experience more serious adverse reactions and have a shorter long-term survival after antitumor therapy than patients without sarcopenia. Antitumor drugs whilst beneficial for tumor regression, interferes and synergizes with cancer-induced muscle wasting/sarcopenia, induced myodemia or intramuscular fat and the two conditions often overlap making it difficult to drive conclusions. In recent years, increasing attention has been paid to the dynamic changes in skeletal muscles during antitumor drug therapy. Dynamic changes refer not only measurement skeletal muscle quantity at baseline level, but give more emphasis on the increasing or decreasing level during or end of the whole treatment course. Methods: We retrievaled published English-language original research articles via pubmed, those studies mainly focused on repeated measurements of skeletal muscle index using computed tomography (CT) in cancer patients who received antitumor drug treatment but not received interventions that produced muscle mass change (such as exercise and nutritional interventions). Conclusion: This article will summarize the research progress to date. Most of antineoplastic drug cause skeletal muscle loss during the treatment course, loss of L3 skeletal muscle index is always associated with poor clinical outcomes.

Intramuscular Adipose Tissue Content Predicts Patient Outcomes after Allogeneic Hematopoietic Stem Cell Transplantation

During clinical courses involving treatment with allogeneic hematopoietic stem cell transplantation (allo-HSCT), multidisciplinary patient assessment including physical function is indispensable, and quantitative skeletal muscle loss is a poor prognostic marker. Deteriorating quality of muscle from intramuscular adipose tissue degeneration can be important as well, because many patients are cachexic or sarcopenic before allo-HSCT, although this approach has not yet been used in such patients. We conducted this retrospective cohort study to evaluate the quality as well as quantity of skeletal muscle using computed tomography (CT) scans. The psoas muscle mass index (PMI) and radiographic density (RD) calculated by cross-sectional area and averaged CT values of the psoas major muscle at the umbilical level were used to determine the quantity and quality of muscle, respectively. A total of 186 adult patients, ranging in age from 17 to 68 years (median, 49 years), were included in this study, with 46 (24.7%) assigned to the lower PMI group and 49 (26.3%) assigned to the lower RD group. Low RD was identified as an independent risk factor for poor overall survival after allo-HSCT (adjusted hazard ratio [HR], 2.54; P < .01), whereas PMI was not significant. Decreased RD along with a reduced 6-min walking distance before transplantation were significant factors in increased nonrelapse mortality (HR, 2.69; P = .01). This study is the first to suggest the use of a qualitative skeletal muscle index to serve as a prognostic indicator following allo-HSCT. RD should be included in pretransplantation screening parameters, and approaches that include rehabilitation focused on improving both muscle quality and quantity may improve the prognosis of allo-HSCT.

Function Over Mass: A Meta-Analysis on the Importance of Skeletal Muscle Quality in COVID-19 Patients

COVID-19 caused by SARS-CoV-2 infection is a highly contagious disease affecting both the higher and lower portions of the respiratory tract. This disease reached over 265 million people and has been responsible for over 5.25 million deaths worldwide. Skeletal muscle quality and total mass seem to be predictive of COVID-19 outcome. This systematic review aimed at providing a critical analysis of the studies published so far reporting on skeletal muscle mass in patients with COVID-19, with the intent of examining the eventual association between muscle status and disease severity. A meta-analysis was performed to evaluate whether skeletal muscle quantity, quality and function were related to disease severity. Systematic reviews and meta-analyses were conducted according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and reported according to the guidelines of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guide. From a total of 1,056 references found, 480 were selected after removing duplicates. Finally, only 7 met the specified inclusion criteria. The results of this meta-analysis showed that skeletal muscle quality, rather than quantity, was associated with COVID-19 severity, as confirmed by lower skeletal muscle density and lower handgrip strength in patients with severe disease. Muscle function assessment can thus be a valuable tool with prognostic value in COVID-19.

Associations of pulmonary and extrapulmonary computed tomographic manifestations with impaired physical activity in symptomatic patients with chronic obstructive pulmonary disease

In patients with chronic obstructive pulmonary disease (COPD), emphysema, airway disease, and extrapulmonary comorbidities may cause various symptoms and impair physical activity. To investigate the relative associations of pulmonary and extrapulmonary manifestations with physical activity in symptomatic patients, this study enrolled 193 patients with COPD who underwent chest inspiratory/expiratory CT and completed COPD assessment test (CAT) and the Life-Space Assessment (LSA) questionnaires to evaluate symptom and physical activity. In symptomatic patients (CAT ≥ 10, n = 100), emphysema on inspiratory CT and air-trapping on expiratory CT were more severe and height-adjusted cross-sectional areas of pectoralis muscles (PM index) and adjacent subcutaneous adipose tissue (SAT index) on inspiratory CT were smaller in those with impaired physical activity (LSA < 60) than those without. In contrast, these findings were not observed in less symptomatic patients (CAT < 10). In multivariable analyses of the symptomatic patients, severe air-trapping and lower PM index and SAT index, but not CT-measured thoracic vertebrae bone density and coronary artery calcification, were associated with impaired physical activity. These suggest that increased air-trapping and decreased skeletal muscle and subcutaneous adipose tissue quantity are independently associated with impaired physical activity in symptomatic patients with COPD.