Mechanisms Underlying Metabolic Syndrome-Related Sarcopenia and Possible Therapeutic Measures

Rodent model intervention for prevention and optimal management of sarcopenia: A systematic review on the beneficial effects of nutrients & non-nutrients and exercise to improve skeletal muscle health

Sarcopenia is a common musculoskeletal disorder characterized by degenerative processes and is strongly linked to an increased susceptibility to falls, fractures, physical limitations, and mortality. Several models have been used to explore therapeutic and preventative measures as well as to gain insight into the molecular mechanisms behind sarcopenia. With novel experimental methodologies emerging to design foods or novel versions of conventional foods, understanding the impact of nutrition on the prevention and management of sarcopenia has become important. This review provides a thorough assessment of the use of rodent models of sarcopenia for understanding the aging process, focusing the effects of nutrients, plant extracts, exercise, and combined interventions on skeletal muscle health. According to empirical research, nutraceuticals and functional foods have demonstrated potential benefits in enhancing physical performance. In preclinical investigations, the administration of herbal extracts and naturally occurring bioactive compounds yielded advantageous outcomes such as augmented muscle mass and strength generation. Furthermore, herbal treatments exhibited inhibitory effects on muscle atrophy and sarcopenia. A substantial body of information establishes a connection between diet and the muscle mass, strength, and functionality of older individuals. This suggests that nutrition has a major impact in both the prevention and treatment of sarcopenia.

Impact of Psoas Muscle Area Index on Short- and Mid-Term Mortality in Patients Undergoing Valve Surgery for Infective Endocarditis: A Retrospective Analysis

Background: Sarcopenia, characterized by the loss of skeletal muscle mass, is an emerging comorbidity associated with poor outcomes in cardiovascular surgery. Its impact on mortality in patients undergoing valve surgery for infective endocarditis (IE) remains underexplored. This study investigates the relationship between sarcopenia, measured by the Psoas muscle area index (PMAi), and mortality in patients with IE undergoing valve surgery. Materials and Methods: We retrospectively analyzed 68 patients with IE who underwent valve surgery at a tertiary care center from 2013 to 2021. Sarcopenia was defined as being in the lowest quartile of PMAi, measured via preoperative computed tomography (CT). Baseline characteristics, survival outcomes, and factors influencing mortality were analyzed using Kaplan-Meier survival curves and Cox proportional hazards regression. The predictive value of PMAi for 1-year and 3-year mortality was assessed via receiver operating characteristic (ROC) curves. Results: Sarcopenia was strongly associated with increased mortality at both 1-year (HR: 0.378, p = 0.010) and 3-year follow-ups (HR: 0.457, p = 0.012). Female sex (OR: 275.748, p < 0.001) and older age (OR: 9.995, p = 0.003) were significant predictors of sarcopenia. Chronic kidney insufficiency (CKI) and the use of heart failure medication therapy also significantly impacted survival outcomes. Conclusions: Sarcopenia is a strong independent predictor of short- and mid-term mortality in patients undergoing valve surgery for IE. Routine radiological assessment of sarcopenia using PMAi could improve risk stratification and guide preoperative interventions. Tailored management strategies, especially in older women and patients with CKI, may enhance outcomes in this high-risk population.

Associations of metabolic syndrome and its components with sarcopenia, and the mediating role of insulin resistance: Findings from NHANES database

BACKGROUND

To investigate the association between metabolic syndrome (MetS) and its components with sarcopenia, and to explore the extent to which insulin resistance (IR) mediates this association, using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

We analyzed cross-sectional data from 15,779 adults in the NHANES from 1999 to 2006 and 2011-2018. Multivariable logistic regression models were used to determine the odds ratios (ORs) between MetS, its components, the number of MetS components, and sarcopenia. Mediation analysis was performed to explore the role of the homeostatic model assessment of insulin resistance (HOMA-IR) in MetS and its components-induced sarcopenia.

RESULT

In the fully adjusted model, MetS increased the prevalence of sarcopenia by 1.96-fold (95% CI: 1.73-2.22). Among the individual components, central obesity, hypertension, and hyperglycemia were associated with an increased prevalence of sarcopenia. Sarcopenia prevalence also increased linearly with the number of MetS components, with the highest prevalence observed in the presence of all five components (OR: 3.80, 95% CI: 2.79-5.16). Sex-stratified analysis showed that the prevalence of MetS for sarcopenia was higher in males than females. The mediating effects of HOMA-IR on the association between MetS and its components (central obesity, hypertension, and hyperglycemia) with sarcopenia were significant, with mediation effects of 51.7%, 30.7%, 33.2%, and 79.1%, respectively. There was no significant direct association between hyperglycemia and sarcopenia beyond the HOMA-IR pathway.

CONCLUSION

MetS and its individual components, excluding hypertriglyceridemia and low high density lipoprotein cholesterol, were associated with a higher prevalence of sarcopenia, especially in males. This association was partially or fully mediated by IR.

Association of triglyceride-glucose index with sarcopenia: NHANES 2011-2014

Background

A newly developed technique, the Triglyceride-glucose (TyG) index, supplies a more straightforward method to identify IR than the HOMA-IR (Homeostasis Model Assessment of Insulin Resistance). Yet no methodical analysis has looked into the link involving the TyG index and low muscle mass (LMM), low muscle strength (LMS), and sarcopenia within the US. Thus, this study intended to find any connection concerning the TyG index and LMM, LMS, and sarcopenia.

Methods

Between 2011 to 2014, data from the NHANES were used to conduct a nationally representative study involving 2,504 participants. LMM, LMS, and sarcopenia were the outcome variables. Moreover, this positive correlation persists irrespective of age and gender.

Results

The TyG index revealed a significant correlation with the prevalence of developing LMM (OR = 1.63(1.26-2.11), p=0.001), LMS (OR = 1.61(1.36-1.91), p<0.001) and sarcopenia (OR = 1.59 (1.23-2.07), p<0.001), after correcting for all variables. Utilizing smooth curve fitting alongside two-piecewise linear regression models, an inverted U-shaped correlation between the TyG index and the prevalence of LMM, LMS, and sarcopenia. Finally, subgroup analysis revealed that the association between the TyG index and LMM, LMS, and sarcopenia was particularly evident in all gender, age subgroups, and individuals with a normal BMI of 25.

Conclusion

Sarcopenia and the TyG index reveal an essential positive link. It highlights the potential utility of the TyG index as a screening tool for identifying individuals at risk of sarcopenia earlier.

Update on Obesity and Cardiovascular Risk: From Pathophysiology to Clinical Management

Obesity is an epidemic worldwide. Overweight and multiple obesity-related mechanisms, including dysmetabolic alterations, contribute to cardiovascular deleterious effects. Hence, overweight and obesity have been independently associated with increased cardiovascular risk, whose assessment is crucial for preserving life quality and reducing mortality, and to address appropriate therapeutic strategies in obese patients. Beyond the standard of care in managing overweight and obesity in adults (i.e., diet and physical exercise), several relevant pharmacotherapies have been approved, and several procedures and device types for weight loss have been recommended. In such a contest, medical weight management remains one option for treating excess weight. Most drugs used for obesity reduce appetite and increase satiety and, secondarily, slow gastric emptying to reduce body weight and, therefore, act also to improve metabolic parameters. In this contest, agonists of the glucagon-like peptide-1 receptor (GLP-1RAs) modulate different metabolic pathways associated with glucose metabolism, energy homeostasis, antioxidation, and inflammation. Moreover, this class of drugs has shown efficacy in improving glycemic control, reducing the incidence of cardiovascular events in type 2 diabetic patients, and reducing body weight independently of the presence of diabetes. Recently, in overweight or obese patients with pre-existing cardiovascular disease but without diabetes, the GLP-1RA semaglutide reduced the incidence of cardiovascular and cerebrovascular events and death from cardiovascular causes. Thus, semaglutide has been approved for secondary prevention in obese people with cardiovascular disease. Nevertheless, whether this class of drugs is equally effective for primary prevention in obese people has to be demonstrated. In this review, we will summarize updates on the pathophysiology of obesity, the effects of obesity on cardiovascular risk, the impact of different obesity phenotypes on cardiovascular diseases, and the novelties in the clinical management of obesity for cardiovascular prevention.

The Association between Body Composition Phenotype and Insulin Resistance in Post-COVID-19 Syndrome Patients without Diabetes: A Cross-Sectional, Single-Center Study

BACKGROUND

The most frequent body composition alterations in post-COVID-19 syndrome include low muscle mass, dynapenia, sarcopenia, and obesity. These conditions share interconnected pathophysiological mechanisms that exacerbate each other. The relationship between body composition phenotypes and metabolic abnormalities in post-COVID-19 syndrome remains unclear.

OBJECTIVE

To evaluate the association between body composition phenotypes and insulin resistance (IR) and metabolic abnormalities in non-diabetic individuals with post-COVID-19 syndrome.

METHODS

A cross-sectional, single-center study involving 483 subjects with post-COVID-19 syndrome following moderate to severe acute COVID-19 requiring hospitalization. Individuals with diabetes, those who declined to participate, or those who could not be contacted were excluded. Body composition phenotypes were classified as normal weight, dynapenia, sarcopenia, dynapenic obesity, and sarcopenic obesity (SO).

RESULTS

The average age was 52.69 ± 14.75 years; of note, 67.08% were male. The prevalence of body composition phenotypes was as follows: 13.25% were of normal weight, 9.52% had dynapenia, 9.94% had sarcopenia, 43.69% had obesity, 18.84% had dynapenic obesity, and 4.76% had SO. Additionally, 58.18% had IR. Obesity (OR: 2.98, CI95%; 1.64-5.41) and dynapenic obesity (OR: 4.98, CI95%; 1.46-6.88) were associated with IR.

CONCLUSION

The most common body composition phenotypes were obesity, dynapenic obesity, and dynapenia. Furthermore, obesity and dynapenic obesity were associated with IR in post-COVID-19 syndrome.

Interactions between myoblasts and macrophages under high glucose milieus result in inflammatory response and impaired insulin sensitivity

BACKGROUND

Skeletal muscle handles about 80% of insulin-stimulated glucose uptake and become the major organ occurring insulin resistance (IR). Many studies have confirmed the interactions between macrophages and skeletal muscle regulated the inflammation and regeneration of skeletal muscle. However, despite of the decades of research, whether macrophages infiltration and polarization in skeletal muscle under high glucose (HG) milieus results in the development of IR is yet to be elucidated. C2C12 myoblasts are well-established and excellent model to study myogenic regulation and its responses to stimulation. Further exploration of macrophages' role in myoblasts IR and the dynamics of their infiltration and polarization is warranted.

AIM

To evaluate interactions between myoblasts and macrophages under HG, and its effects on inflammation and IR in skeletal muscle.

METHODS

We detected the polarization status of macrophages infiltrated to skeletal muscles of IR mice by hematoxylin and eosin and immunohistochemical staining. Then, we developed an in vitro co-culture system to study the interactions between myoblasts and macrophages under HG milieus. The effects of myoblasts on macrophages were explored through morphological observation, CCK-8 assay, Flow Cytometry, and enzyme-linked immunosorbent assay. The mediation of macrophages to myogenesis and insulin sensitivity were detected by morphological observation, CCK-8 assay, Immunofluorescence, and 2-NBDG assay.

RESULTS

The F4/80 and co-localization of F4/80 and CD86 increased, and the myofiber size decreased in IR group (P < 0.01, g = 6.26). Compared to Mc group, F4/80+CD86+CD206- cells, tumor necrosis factor-α (TNFα), inerleukin-1β (IL-1β) and IL-6 decreased, and IL-10 increased in McM group (P < 0.01, g > 0.8). In McM + HG group, F4/80+CD86+CD206- cells, monocyte chemoattractant protein 1, TNFα, IL-1β and IL-6 were increased, and F4/80+CD206+CD86- cells and IL-10 were decreased compared with Mc + HG group and McM group (P < 0.01, g > 0.8). Compered to M group, myotube area, myotube number and E-MHC were increased in MMc group (P < 0.01, g > 0.8). In MMc + HG group, myotube area, myotube number, E-MHC, GLUT4 and glucose uptake were decreased compared with M + HG group and MMc group (P < 0.01, g > 0.8).

CONCLUSION

Interactions between myoblasts and macrophages under HG milieus results in inflammation and IR, which support that the macrophage may serve as a promising therapeutic target for skeletal muscle atrophy and IR.

Gracilaria chorda attenuates obesity-related muscle wasting through activation of SIRT1/PGC1α in skeletal muscle of mice

Gracilaria chorda (GC) is a red algal species that is primarily consumed in Asia. Here, we investigated the effect of GC on obesity-related skeletal muscle wasting. Furthermore, elucidating its impact on the activation of sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α) constituted a critical aspect in understanding the underlying mechanism of action. In this study, 6-week-old male C57BL/6 mice were fed a high-fat diet (HFD) for 8 weeks to induce obesity, then continued on the HFD for another 8 weeks while orally administered GC. GC decreased ectopic fat accumulation in skeletal muscle and increased muscle weight, size, and function in obese mice. Furthermore, GC reduced skeletal muscle atrophy and increased hypertrophy in mice. We hypothesized that the activation of SIRT1/PGC1α by GC regulates skeletal muscle atrophy and hypertrophy. We observed that GC increased the expression of SIRT1 and PGC1α in skeletal muscle of mice and in C2C12 cells, which increased mitochondrial function and biogenesis. In addition, when C2C12 cells were treated with the SIRT1-specific inhibitor EX-527, no changes were observed in the protein levels of SIRT1 and PGC1α in the GC-treated C2C12 cells. Therefore, GC attenuated obesity-related muscle wasting by improving mitochondrial function and biogenesis through the activation of SIRT1/PGC1α in the skeletal muscle of mice.

Role of Nutrition in the Management of Patients with Chronic Musculoskeletal Pain

Chronic musculoskeletal pain (CMP), defined as persistent discomfort in musculoskeletal tissues persisting for over 3 months, afflicts an estimated 1.71 billion people globally, leading to significant functional impairments and psychological distress, thereby detrimentally affecting individuals' quality of life. The objective of this narrative review is to elucidate the complex relationship among dietary habits, sarcopenia, and gut microbiota composition, with an eye toward enhancing patient management and outcomes. Given the burgeoning interest in the influence of diet on CMP, a detailed examination of the current literature is warranted. Nutritional intake is a critical determinant of the gut microbiota profile, which, in turn, is linked to musculature integrity and performance, potentially leading to sarcopenia. The development of sarcopenia can aggravate CMP owing to diminished muscular strength and functionality. Additionally, disruptions in the gut microbiota may directly modulate nociception, intensifying CMP manifestations. Thus, nutritional optimization emerges as a viable approach to CMP management. Emphasizing a diet conducive to a healthy gut microbiome could forestall or mitigate sarcopenia, thereby attenuating CMP intensity. Nevertheless, the domain calls for further empirical exploration to unravel the nuances of these interactions and to forge efficacious dietary strategies for individuals with CMP. Beyond mere analgesia, comprehensive patient care for CMP requires acknowledgment of the complex and multifactorial nature of pain and its foundational elements. Embracing an integrative treatment model allows healthcare practitioners to promise better patient prognoses, enriched life quality, and a decrease in the sustained healthcare costs associated with CMP.

Associated factors of low muscle mass in community-dwelling patients with type 2 diabetes

This study aims to analyze the prevalence of low muscle mass (LMM) and its associated factors among community-dwelling patients with type 2 diabetes (T2D). A retrospective design was employed to analyze the body composition of 2404 adults with T2D aged 18 years and older. LMM was defined as a skeletal muscle index < 7.0 kg/m2 for males and skeletal muscle index < 5.7 kg/m2 for females by bioelectrical impedance analyzer (InBody 770, Korea). Multivariable logistic regression was used to identify the factors related to LMM. The overall prevalence of LMM was 28%. After adjusting for multivariate odds ratios, factors significantly associated with LMM in patients with diabetes include being older than 75 years, female, having a body mass index of <18 kg/m2, and increased percent body fat. We recommend regular LMM evaluations for T2D patients with the previously mentioned characteristics as part of diabetes care.

Effects of a Multicomponent Preventive Intervention in Women at Risk of Sarcopenia: A Pilot Study

Sarcopenia is defined by the presence of decreased skeletal muscle mass, strength, and functionality in older people. Multicomponent interventions represent an alternative to non-pharmacological treatment for preventing disease progression. This study aimed to evaluate the effects of a multicomponent intervention approach in women at risk of sarcopenia.

METHODS

A quasi-experimental pilot study of 12 weeks was conducted, with 24 sessions of dancing and resistance exercises and 12 sessions of nutritional education. The outcomes were changes in muscle mass, grip strength, gait speed, and body composition. The project was registered on Clinical Trials: NCT06038500 (14 September 2023).

RESULTS

Twelve women aged 55-75 years participated in this study; after the intervention, changes were found in the following variables: grip strength, from 18.70 (17.98-19.23) at baseline to 21.57 (20.67-23.16) kg (p = 0.002); gait speed, from 0.95 (0.81-1.18) at baseline to 1.34 (1.20-1.47) m/s (p = 0.003); and hip circumference, from 99.75 (94.75-110.37) at baseline to 97.65 (93.92-109.50) cm (p = 0.023). Other measurements that appeared without changes were appendicular skeletal muscle mass, from 21.17 (18.58-22.33) at baseline to 20.77 (18.31-22.39) kg (p = 0.875), and the appendicular skeletal muscle mass index, from 8.64 (8.08-9.35) at baseline to 8.81 (7.91-9.38) kg/m2 (p = 0.875) after the intervention.

CONCLUSIONS

The three-month multicomponent intervention in women at risk of sarcopenia improved their grip strength and gait speed.

Exploring the Pathophysiology of Long COVID: The Central Role of Low-Grade Inflammation and Multisystem Involvement

Long COVID (LC), also referred to as Post COVID-19 Condition, Post-Acute Sequelae of SARS-CoV-2 Infection (PASC), and other terms, represents a complex multisystem disease persisting after the acute phase of COVID-19. Characterized by a myriad of symptoms across different organ systems, LC presents significant diagnostic and management challenges. Central to the disorder is the role of low-grade inflammation, a non-classical inflammatory response that contributes to the chronicity and diversity of symptoms observed. This review explores the pathophysiological underpinnings of LC, emphasizing the importance of low-grade inflammation as a core component. By delineating the pathogenetic relationships and clinical manifestations of LC, this article highlights the necessity for an integrated approach that employs both personalized medicine and standardized protocols aimed at mitigating long-term consequences. The insights gained not only enhance our understanding of LC but also inform the development of therapeutic strategies that could be applicable to other chronic conditions with similar pathophysiological features.

Association of the oxidative balance score with sarcopenia among young and middle-aged adults: findings from NHANES 2011-2018

Background

Sarcopenia is associated with oxidative stress. The Oxidative Balance Score (OBS) is commonly used to assess dietary and lifestyle exposure to oxidative stress. However, few studies in the literature have assessed the correlation between sarcopenia and OBS.

Aim

This study aimed to assess the association between OBS and sarcopenia among young and middle-aged adults in the United States using data from the National Health and Nutrition Examination Survey (NHANES).

Method

Weighted logistic regression analysis was used to investigate the association between OBS and sarcopenia based on data from NHANES 2011-2018. Subgroup analyses were performed to observe the consistency of the outcomes, and the stability of the results was tested using sensitivity analyses.

Result

The final sample included 5,525 young and middle-aged American adults. A higher OBS was associated with a lower risk of sarcopenia. In the fully adjusted model, the second (odds ratio [OR]: 0.62, 95% confidence interval [CI]: 0.41, 0.94; p = 0.023), third (OR: 0.50; 95% CI: 0.34, 0.74; p < 0.001), and highest quartiles (OR: 0.18; 95% CI: 0.11, 0.28; p < 0.001) of the OBS were associated with higher risks of sarcopenia when compared to the lowest quartile. This association was consistent across both dietary and lifestyle OBS scores. Our subgroup analysis revealed no significant differences between the subgroups of variables included in the interaction analysis. Sensitivity analyses revealed similar results.

Conclusion

Our study showed that higher antioxidant and lower antioxidant exposure may decrease the risk of developing sarcopenia. Higher OBS scores may indicate greater protection against sarcopenia; however, further clinical studies are warranted to confirm these findings.

The effects of exposure to and timing of a choline-deficient diet during pregnancy and early postnatal life on the skeletal muscle transcriptome of the offspring

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is related to muscle loss, but the precise mechanism underlying this association remains unclear. The aim of the present study was thus to determine the influence of maternal fatty liver and dietary choline deficiency during pregnancy and/or lactation periods on the skeletal muscle gene expression profile among 24-day-old male rat offspring.

METHODS

Histological examination of skeletal muscle tissue specimens obtained from offspring of dams suffering from fatty liver, provided with proper choline intake during pregnancy and lactation (NN), fed a choline-deficient diet during both periods (DD), deprived of choline only during pregnancy (DN), or only during lactation (ND), was performed. The global transcriptome pattern was assessed using a microarray approach (Affymetrix® Rat Gene 2.1 ST Array Strip). The relative expression of selected genes was validated by real-time PCR (qPCR).

RESULTS

Morphological differences in fat accumulation in skeletal muscle related to choline supply were observed. The global gene expression profile was consistent with abnormal morphological changes. Mettl21c gene was overexpressed in all choline-deficient groups compared to the NN group, while two genes, Cdkn1a and S100a4, were downregulated. Processes of protein biosynthesis were upregulated, and processes related to cell proliferation and lipid metabolism were inhibited in DD, DN, and ND groups compared to the NN group.

CONCLUSIONS

Prenatal and early postnatal exposure to fatty liver and dietary choline deficiency leads to changes in the transcriptome profile in skeletal muscle of 24-day old male rat offspring and is associated with muscle damage, but the mechanism of it seems to be different at different developmental stages of life. Adequate choline intake during pregnancy and lactation can prevent severe muscle disturbance in the progeny of females suffering from fatty liver.

Navigating the Intersection: Sarcopenia and Sarcopenic Obesity in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are intricate systemic conditions that can extend beyond the gastrointestinal tract through both direct and indirect mechanisms. Sarcopenia, characterized by a reduction in muscle mass and strength, often emerges as a consequence of the clinical course of IBDs. Indeed, sarcopenia exhibits a high prevalence in Crohn's disease (52%) and ulcerative colitis (37%). While computed tomography and magnetic resonance imaging remain gold-standard methods for assessing muscle mass, ultrasound is gaining traction as a reliable, cost-effective, and widely available diagnostic method. Muscle strength serves as a key indicator of muscle function, with grip strength test emerging nowadays as the most reliable assessment method. In IBDs, sarcopenia may arise from factors such as inflammation, malnutrition, and gut dysbiosis, leading to the formulation of the 'gut-muscle axis' hypothesis. This condition determines an increased need for surgery with poorer post-surgical outcomes and a reduced response to biological treatments. Sarcopenia and its consequences lead to reduced quality of life (QoL), in addition to the already impaired QoL. Of emerging concern is sarcopenic obesity in IBDs, a challenging condition whose pathogenesis and management are still poorly understood. Resistance exercise and nutritional interventions, particularly those aimed at augmenting protein intake, have demonstrated efficacy in addressing sarcopenia in IBDs. Furthermore, anti-TNF biological therapies showed interesting outcomes in managing this condition. This review seeks to furnish a comprehensive overview of sarcopenia in IBDs, elucidating diagnostic methodologies, pathophysiological mechanisms, and clinical implications and management. Attention will also be paid to sarcopenic obesity, exploring the pathophysiology and possible treatment modalities of this condition.

Association of the triglyceride-glucose index and its related parameters with frailty

BACKGROUND

Frailty is a dynamic geriatric condition. Limited studies have examined the association of the triglyceride-glucose (TyG) index and its related indicators [TyG index, triglyceride glucose-waist to height ratio (TyG-WHtR), triglyceride glucose-waist circumference (TyG-WC), and triglyceride glucose-body mass index (TyG-BMI)] with frailty, and the potential links among them remain unclear. On the basis of data from the National Health and Nutrition Examination Survey (NHANES), this study investigated the potential relationships of the TyG index and its related indices with frailty.

METHODS

This research included 7,965 participants from NHANES 2003-2018. The relationship of the TyG index and its related indices with frailty was investigated with binary logistic regression analyses, restricted cubic spline (RCS), and receiver operating characteristic (ROC) curve. Potential influences were further investigated through stratified analyses and interaction tests.

RESULTS

The prevalence of frailty in the participants of this study was 25.59%, with a average frailty index of 0.16 (0.00). In the three regression analysis models, the continuous TyG index and its associated indices were positively associated with frailty. In addition, quartiles of TyG, TyG-WC, TyG-WHtR, and TyG-BMI were significantly associated with increased frailty prevalence in the fully adjusted models (TyG Q4 vs. Q1, OR = 1.58, 95% CI: 1.19, 2.09, P = 0.002; TyG-WC Q4 vs. Q1, OR = 2.40, 95% CI: 1.90, 3.04, P < 0.001; TyG-WHtR Q4 vs. Q1, OR = 2.26, 95% CI: 1.82, 2.81, P < 0.001; TyG- BMI Q4 vs. Q1, OR = 2.16, 95% CI: 1.76, 2.64, P < 0.001). According to RCS analysis, TyG, TyG-WC, TyG-WHtR, and TyG-BMI were linearly and positively associated with frailty. ROC curves revealed that TyG-WHtR (AUC: 0.654) had greater diagnostic value for frailty than TyG (AUC: 0.604), TyG-BMI (AUC: 0.621), and TyG-WC (AUC: 0.629). All of the stratified analyses and interaction tests showed similar results.

CONCLUSIONS

Elevated TyG and its associaed indices are associated with an increased prevalence of frailty. Reasonable control of blood glucose and blood lipids, and avoidance of obesity, may aid in reducing the occurrence of frailty in middle-aged and older adults.

The Influence of Stress and Binge-Patterned Alcohol Drinking on Mouse Skeletal Muscle Protein Synthesis and Degradation Pathways

Adverse experiences (e.g., acute stress) and alcohol misuse can both impair skeletal muscle homeostasis, resulting in reduced protein synthesis and greater protein breakdown. Exposure to acute stress is a significant risk factor for engaging in alcohol misuse. However, little is known about how these factors together might further affect skeletal muscle health. To that end, this study investigated the effects of acute stress exposure followed by a period of binge-patterned alcohol drinking on signaling factors along mouse skeletal muscle protein synthesis (MPS) and degradation (MPD) pathways. Young adult male C57BL/6J mice participated in the Drinking in the Dark paradigm, where they received 2-4 h of access to 20% ethanol (alcohol group) or water (control group) for four days to establish baseline drinking levels. Three days later, half of the mice in each group were either exposed to a single episode of uncontrollable tail shocks (acute stress) or remained undisturbed in their home cages (no stress). Three days after stress exposure, mice received 4 h of access to 20% ethanol (alcohol) to model binge-patterned alcohol drinking or water for ten consecutive days. Immediately following the final episode of alcohol access, mouse gastrocnemius muscle was extracted to measure changes in relative protein levels along the Akt-mTOR MPS, as well as the ubiquitin-proteasome pathway (UPP) and autophagy MPD pathways via Western blotting. A single exposure to acute stress impaired Akt singling and reduced rates of MPS, independent of alcohol access. This observation was concurrent with a potent increase in heat shock protein seventy expression in the muscle of stressed mice. Alcohol drinking did not exacerbate stress-induced alterations in the MPS and MPD signaling pathways. Instead, changes in the MPS and MPD signaling factors due to alcohol access were primarily observed in non-stressed mice. Taken together, these data suggest that exposure to a stressor of sufficient intensity may cause prolonged disruptions to signaling factors that impact skeletal muscle health and function beyond what could be further induced by periods of alcohol misuse.

Comparison of Absolute and Relative Grip Strength to Predict Incidence of Metabolic Syndrome: Eight-Year Follow-Up Study in Korea

Background: This study aimed to conduct an analysis of longitudinal study to investigate the association of absolute grip strength, and relative grip strength with incidence of metabolic syndrome. Materials and Methods: Participants who participated in the Korean Genome and Epidemiology Study, a chronic screening program conducted in Ahnseong-si, Gyeonggi-do, a primary survey conducted from 2013 to 2014 were selected. The presence of metabolic syndrome was classified using the standards of the International Diabetes Foundation following previous studies. Grip strength was measured using a JAMA 5030J1 (Saehan, Korea) and calculated the absolute grip strength and relative grip strength. To evaluate the relationship between the absolute grip strength, relative grip strength, and incidence of metabolic syndrome, independent hazard ratios (HRs) and 95% confidence intervals (CIs) for metabolic syndrome were calculated according to absolute and relative grip strength levels using a multivariate extended Cox regression model. Results: The incidence of metabolic syndrome was reduced by 38% (HR = 0.62, 95% CI = 0.43-0.88) for the high absolute grip strength group, compared to the low absolute grip strength group. Also, this study confirmed that the incidence of metabolic syndrome for mid relative grip strength and high relative grip strength groups were reduced by 27% (HR = 0.73, 95% CI = 0.55-0.98) and 55% (HR = 0.45, 95% CI = 0.32-0.64) respectively. Moreover, the incidence of metabolic syndrome was reduced by 45% (HR = 0.55, 95% CI = 0.37-0.82) and 57% (HR = 0.43, 95% CI = 0.29-0.65) for the low-level body mass index (BMI) group with high or low absolute grip strength, respectively. Finally, this study confirmed the association of sex, absolute grip strength, and relative grip strength according to age with incidence of metabolic syndrome was different. Conclusion: We observed that relative grip strength has a higher association with incidence of metabolic syndrome than absolute grip strength. Also, BMI has a higher association with metabolic syndrome than the absolute grip strength.

Associations between low muscle mass and clinical characteristics of health population in China

Objectives

The primary aim of this study is to discern the association between specific clinical parameters and low muscle mass (LMM). We endeavor to elucidate the determinants of LMM and the predictive potency of individual factors.

Methods

In this retrospective cross-sectional study, we encompassed 450 older adult Chinese participants (252 males and 198 females). Muscle mass quantifications were performed using bioelectrical impedance analysis. Comprehensive data encompassing demographic details (age, sex, height, and weight) and laboratory results (complete blood count, thyroid function, liver function, and renal function) were systematically recorded. Logistic regression models, coupled with receiver operating characteristic curve analytics, were employed to ascertain the variables influencing LMM and to evaluate the predictive validity of each parameter on LMM.

Results

Upon confounding adjustment for age, gender, body mass index (BMI), and free thyroxine (FT4) persisted as a determinant of LMM. Specifically, individuals with an FT4 exceeding 1.105 ng/dL exhibited a 1.803-fold increased propensity for LMM relative to those with FT4 values below the specified threshold. Incorporating age, gender, BMI, and FT4 in the diagnostic algorithm enhanced the precision of LMM. The results differ between men and women. In the male population, we can still observe that FT4 has a certain value in the diagnosis of LMM, but this phenomenon is not found in the female population.

Conclusions

Elevated FT4 concentrations, albeit within clinically accepted limits, are inversely associated with muscle mass. As such, FT4 could be postulated as a potential biomarker for LMM in geriatric individuals, especially in the male group.

Association of dietary fat intake with skeletal muscle mass and muscle strength in adults aged 20-59: NHANES 2011-2014

Background

Sarcopenia, a progressive loss of skeletal muscle mass and strength, needs to initially prevent in the twenties. Meanwhile, there is a lack of research on the effects of fat consumption on skeletal muscle mass and strength in adults aged 20-59. We aimed to assess associations between dietary fat intake and skeletal muscle mass, as measured by appendicular lean mass adjusted for body mass index (ALMBMI), and muscle strength, as represented by handgrip strength adjusted for body mass index (GSMAXBMI), among adults aged 20-59.

Methods

Dietary fat intake per kilogram of actual body weight was assessed using two 24h recalls, while ALM and GSMAX were measured using DXA and a handgrip dynamometer, respectively. A weighted multiple linear regression model was employed to analyze the association between dietary fat intake and skeletal muscle mass, utilizing data from the National Health and Nutrition Examination Survey spanning from 2011 to 2014. To assess the non-linear relationship and saturation value between dietary fat intake and skeletal muscle mass, a smooth curve fitting approach and a saturation effect analysis model were utilized.

Results

The study comprised a total of 5356 subjects. After adjusting for confounding factors, there was a positive association observed between dietary fat intake and ALMBMI as well as GSMAXBMI. The relationship between dietary fat intake and ALMBMI showed an inverted U-shaped curve, as did the association with GSMAXBMI. Turning points were observed at 1.88 g/kg/d for total fat intake and ALMBMI, as well as at 1.64 g/kg/d for total fat intake and GSMAXBMI. Furthermore, turning points were still evident when stratifying by gender, age, protein intake, and physical activity. The turning points were lower in individuals with low protein intake(<0.8 g/kg/d) and high levels of physical activity.

Conclusion

The moderate dietary fat intake can be beneficial for muscle mass and strength in adults aged 20-59 under specific conditions. Special attention should be directed toward the consumption of fats in individuals with low protein intake and those engaged in high levels of physical activity.

Body Composition in Chronic Liver Disease

Body composition has recently been attracting people's attention, not only from a cosmetic standpoint but also from the perspective of health and longevity. The body is classified into three components: fat, bone, and lean soft tissue, and it is common to see an increase in body fat and a decrease in total body muscle mass with aging. Aging-related loss of muscle mass and muscle function is referred to as primary sarcopenia, while sarcopenia caused by disease-specific conditions is referred to as secondary sarcopenia. On the other hand, the liver-muscle axis has been attracting attention in recent years, and it has become clear that the liver and the skeletal muscles interact with each other. In particular, patients with cirrhosis are prone to secondary sarcopenia due to protein-energy malnutrition, which is a characteristic pathophysiology of the disease, suggesting the importance of the organ-organ network. In this review, we would like to outline the latest findings in this field, with a focus on body composition in liver diseases such as liver cirrhosis, fatty liver disease, alcoholic liver disease, and hepatocellular carcinoma.

The impact of Helicobacter pylori infection on low skeletal muscle mass risk in Chinese women over 40: a cross-sectional analysis

Background

Sarcopenia can lead to significant personal, social, and economic burdens. The diagnosis of sarcopenia heavily relies on the identification of Low Skeletal Muscle Mass (LSMM), which is an independent predictor of frailty, disability, and increased risk of death among seniors. Women have physiologically lower levels of skeletal muscle mass than men, and female sarcopenia appears to be more influenced by menopause. They also tend to have higher body fat levels than man, which increases the risk of sarcopenia obesity. On another front, it's also recognized that humans are largely prone to Helicobacter pylori (H. pylori) infection, with global prevalence rates often surpassing 50%. Nevertheless, the interconnection between H. pylori infection and LSMM remains relatively unexplored. Hence, our study specifically targeted women as the research population and sought to explore several risk factors for LSMM. Additionally, we delved into the potential correlation between LSMM and H. pylori infection in women, hoping to gain insights into potential preventative measures or treatment options that may enhance the quality of life for women affected by sarcopenia.

Methods

We conducted a cross-sectional study among women aged over 18 years undergoing physical examination. We performed 13C-urea breath test (UBT) for diagnosis of H. pylori infection and Bioelectrical impedance analysis (BIA) for the assessment of LSMM. Logistic regression models were used to analyze the associations of H. pylori infection with LSMM.

Results

This study enrolled 1984 Chinese women who were undergoing health check-ups. A univariate logistic regression analysis did not reveal a direct correlation between H. pylori infection and LSMM among this female population (OR=1.149, 95% CI 0.904-1.459, p=0.257). Yet, upon dividing the participants into age-based subgroups, an evident link was observed between H. pylori infection and LSMM in women aged 40 or above (OR=1.381, 95%CI 1.032-1.848, p= 0.030). After adjusting for variables including Age, BMI, TP, ALK, Cre, this relationship remained statistically relevant (OR=1.514, 95%CI 1.085-2.113, p= 0.015).

Conclusions

Women who are over 40 years old and currently infected with H. pylori have an increased risk of developing LSMM. Therefore, timely treatment for H. pylori eradication is recommended for this group of women to reduce the occurrence of LSMM.

The aspartate aminotransferase to alanine aminotransferase ratio: A novel indicator for skeletal muscle mass in Chinese community adults

OBJECTIVES

The aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio, an indicator for liver fibrosis, could be easily detected in clinical practice. The aim of this study was to examine the association between the AST/ALT ratio and skeletal muscle mass among Chinese community adult residents.

METHODS

We enrolled 2644 participants, age ≥18 y, undergoing bioelectrical impedance analysis and liver function test. Univariate and multivariate logistic regression models were used to analyze the effect of the AST/ALT ratio on the presence of low muscle mass (LMM). Multiple linear regression analysis was used to assess the factors associated with the skeletal muscle mass index (SMI) and to construct a formula to calculate the SMI.

RESULTS

When the AST/ALT ratio was regarded as a categorical variable, AST/ALT quartiles 9-2.19) kept independent effects on the presence of LMM status. When it was regarded as a continuous variable, each unit of the AST/ALT ratio was significantly associated with a 49% (P < 0.01) augment of the prevalence of LMM. By multiple general linear regression analysis, the formula was constructed with an adjusted R2 of 0.72: SMI (kg/m2) = -0.14 AST/ALT ratio + 1.35 sex (male: 1; female: 0) + 0.72 overweight status (yes: 1; no: 0) - 0.14 age (≤65: 0; >65: 1) + 6.26.

CONCLUSION

In general, the high AST/ALT ratio was an independent adverse indicator of the presence of LMM.

Sarcopenia in a type 2 diabetic state: Reviewing literature on the pathological consequences of oxidative stress and inflammation beyond the neutralizing effect of intracellular antioxidants

Sarcopenia remains one of the major pathological features of type 2 diabetes (T2D), especially in older individuals. This condition describes gradual loss of muscle mass, strength, and function that reduces the overall vitality and fitness, leading to increased hospitalizations and even fatalities to those affected. Preclinical evidence indicates that dysregulated mitochondrial dynamics, together with impaired activity of the NADPH oxidase system, are the major sources of oxidative stress that drive skeletal muscle damage in T2D. While patients with T2D also display relatively higher levels of circulating inflammatory markers in the serum, including high sensitivity-C-reactive protein, interleukin-6, and tumor necrosis factor-α that are independently linked with the deterioration of muscle function and sarcopenia in T2D. In fact, beyond reporting on the pathological consequences of both oxidative stress and inflammation, the current review highlights the importance of strengthening intracellular antioxidant systems to preserve muscle mass, strength, and function in individuals with T2D.

A Higher Skeletal Muscle Mass and Lower Adiposity Phenotype Is Associated with Better Cardiometabolic Control in Adults with Hip and Knee Osteoarthritis: Results from the Chilean National Health Survey 2016-2017

OBJECTIVE

This study aimed to (1) characterize cardiometabolic factors in self-reported hip and knee osteoarthritis (OAD) across four body composition phenotypes defined by muscle mass and adiposity, and (2) associate risk factors with diabetes and hypertension (HTN).

METHODS

A cross-sectional analysis of the Chilean National Health Survey 2016-17 (n = 4996) stratified participants into four groups: low skeletal muscle mass/high waist circumference (Low-SMM/High-WC), low SMM/low WC (Low-SMM/Low-WC), high SMM/high WC (High-SMM/High-WC), and high SMM/low WC (reference group). Each group was further divided into subgroups with or without diagnosed hip or knee OAD. The main outcomes were fasting plasma glucose, systolic (SBP)/diastolic (DBP) blood pressure (continuous outcomes), and other secondary factors such as cardiovascular risk (CVR).

RESULTS

In the hip OAD subgroup, the Low-SMM/High-WC groups had significantly higher SBP versus the reference value (145 vs. 127 mmHg, p < 0.0001, diff +18 mmHg). In the knee OAD subgroup, the Low-SMM/High-WC groups had significantly higher SBP versus the reference value (141 vs. 134 mmHg, p < 0.0001, diff +7 mmHg). The SBP showed a significant interaction between the group and OAD diagnosis (p = 0.007 hip OAD; p < 0.0001 knee OAD).

CONCLUSIONS

Hip and knee OAD associates with elevated SBP/DBP in older adults. OAD groups showed an OR above 2 for diabetes, 2.7 for HTN, 4.5 for metabolic syndrome, and over 2 for moderate-to-high cardiovascular risk. OAD interacts substantially with cardiometabolic factors, especially in low muscle mass/high adiposity phenotypes. Lifestyle optimization of physical activity and nutrition to preserve muscle mass and mitigate adiposity is essential for cardiometabolic health promotion in OAD patients.

Irisin Ameliorated Skeletal Muscle Atrophy by Inhibiting Fatty Acid Oxidation and Pyroptosis Induced by Palmitic Acid in Chronic Kidney Disease

INTRODUCTION

Protein-energy waste (PEW) is a common complication in patients with chronic kidney disease (CKD), among which skeletal muscle atrophy is one of the most important clinical features of PEW. Pyroptosis is a type of proinflammatory, programmed cell death associated with skeletal muscle disease. Irisin, as a novel myokine, has attracted extensive attention for its protective role in the complications associated with CKD, but its role in muscle atrophy in CKD is unclear.

METHODS

Palmitic acid (PA)-induced muscular atrophy was evaluated by a reduction in C2C12 myotube diameter. Muscle atrophy model was established in male C57BL/6J mice treated with 0.2% adenine for 4 weeks and then fed a 45% high-fat diet. Blood urea nitrogen and creatinine levels, body and muscle weight, and muscle histology were assessed. The expression of carnitine palmitoyltransferase 1A (CPT1A) and pyroptosis-related protein was analysed by Western blots or immunohistochemistry. The release of IL-1β was detected by enzyme-linked immunosorbent assay.

RESULTS

In this study, we showed that PA-induced muscular atrophy manifested as a reduction in C2C12 myotube diameter. During this process, PA can also induce pyroptosis, as shown by the upregulation of NLRP3, cleaved caspase-1 and GSDMD-N expression and the increased IL-1β release and PI-positive cell rate. Inhibition of caspase-1 or NLRP3 attenuated PA-induced pyroptosis and myotube atrophy in C2C12 cells. Importantly, irisin treatment significantly ameliorated PA-induced skeletal muscle pyroptosis and atrophy. In terms of mechanism, PA upregulated CPT1A, a key enzyme of fatty acid oxidation (FAO), and irisin attenuated this effect, which was consistent with etomoxir (CPT1A inhibitor) treatment. Moreover, irisin improved skeletal muscle atrophy and pyroptosis in adenine-induced mice by regulating FAO.

CONCLUSION

Our study firstly verifies that pyroptosis is a novel mechanism of skeletal muscle atrophy in CKD. Irisin ameliorates skeletal muscle atrophy by inhibiting FAO and pyroptosis in CKD, and irisin may be developed as a potential therapeutic agent for the treatment of muscle wasting in CKD patients.

Mitochondrial dysfunction and skeletal muscle atrophy: Causes, mechanisms, and treatment strategies

Skeletal muscle, which accounts for approximately 40% of total body weight, is one of the most dynamic and plastic tissues in the human body and plays a vital role in movement, posture and force production. More than just a component of the locomotor system, skeletal muscle functions as an endocrine organ capable of producing and secreting hundreds of bioactive molecules. Therefore, maintaining healthy skeletal muscles is crucial for supporting overall body health. Various pathological conditions, such as prolonged immobilization, cachexia, aging, drug-induced toxicity, and cardiovascular diseases (CVDs), can disrupt the balance between muscle protein synthesis and degradation, leading to skeletal muscle atrophy. Mitochondrial dysfunction is a major contributing mechanism to skeletal muscle atrophy, as it plays crucial roles in various biological processes, including energy production, metabolic flexibility, maintenance of redox homeostasis, and regulation of apoptosis. In this review, we critically examine recent knowledge regarding the causes of muscle atrophy (disuse, cachexia, aging, etc.) and its contribution to CVDs. Additionally, we highlight the mitochondrial signaling pathways involvement to skeletal muscle atrophy, such as the ubiquitin-proteasome system, autophagy and mitophagy, mitochondrial fission-fusion, and mitochondrial biogenesis. Furthermore, we discuss current strategies, including exercise, mitochondria-targeted antioxidants, in vivo transfection of PGC-1α, and the potential use of mitochondrial transplantation as a possible therapeutic approach.

Handgrip Strength Is Associated with Specific Aspects of Vascular Function in Individuals with Metabolic Syndrome

BACKGROUND

Metabolic syndrome (MetS) is a disorder associated with an increased risk for the development of diabetes mellitus and its complications. Lower isometric handgrip strength (HGS) is associated with an increased risk of cardiometabolic diseases. However, the association between HGS and arterial stiffness parameters, which are considered the predictors of morbidity and mortality in individuals with MetS, is not well defined.

OBJECTIVE

To determine the association between HGS and HGS asymmetry on components of vascular function in adults with MetS.

METHODS

We measured handgrip strength normalized to bodyweight (HGS/kg), HGS asymmetry, body composition, blood glucose, lipid profile, blood pressure, pulse wave velocity (PWV), reflection coefficient (RC), augmentation index @75 bpm (AIx@75) and peripheral vascular resistance (PVR) in 55 adults with a diagnosis of MetS between 25 and 54 years old.

RESULTS

Mean age was 43.1 ± 7.0 years, 56.3% were females. HGS/kg was negatively correlated with AIx@75 (r = -0.440), p < 0.05, but these associations were not significant after adjusting for age and sex. However, when interaction effects between sex, HGS/kg and age were examined, we observed an inverse relationship between HGS/kg and AIx@75 in the older adults in the sample, whereas in the younger adults, a weak direct association was found. We also found a significant association between HGS asymmetry and PVR (beta = 30, 95% CI = 7.02; 54.2; p <0.012).

CONCLUSIONS

Our findings suggest that in people with MetS, maintaining muscle strength may have an increasingly important role in older age in the attenuation of age-related increases in AIx@75-a marker of vascular stiffness-and that a higher HGS asymmetry could be associated with a greater vascular resistance.

Association between dietary inflammatory index and low muscle mass in diabetes/prediabetes patients

BACKGROUND

Growing evidence has increasingly validated that individuals with diabetes/prediabetes have a higher prevalence of low skeletal muscle mass and function compared to healthy individuals. The anti-inflammatory diet is considered a promising and modifiable approach to optimize skeletal muscle quality. However, current evidence on the relation of dietary inflammatory potential with low muscle mass among diabetic/prediabetic patients is limited.

METHODS

Dietary consumption was determined by trained staff using the 24-hour diet recall method, and the Dietary Inflammatory Index (DII) was scored based on a previously validated approach that included 26 food parameters. Dual-energy X-ray absorptiometry was used to assess the mass of skeletal muscle and low muscle mass was defined based on the sarcopenia index. Logistic regression was conducted to calculate odds ratios (ORs) and 95 % confidence intervals (CIs). Restricted cubic spline (RCS) analysis was also performed to visually represent the relationship between DII and low muscle mass. Furthermore, sensitivity and subgroup analyses were conducted.

RESULTS

In this study, a total of 4269 eligible participants were registered, comprising 1975 (46.26 %) females and 2294 (53.74 %) males. The mean age was 49.98 ± 0.31 years old, and the mean DII score was 1.53 ± 0.04. Among them, 934 (21.88 %) patients were defined as having low muscle mass, while 3335 (78.12 %) were without low muscle mass. The highest tertile (T3) of DII had an 61 % increased risk of low muscle mass (OR = 1.61, 95%CI: 1.19-2.17, p for trend = 0.004) compared to the lowest tertile. The RCS curve displayed a linear dose-response relationship between DII score and low muscle mass risk in patients with diabetes/prediabetes. Subgroup and sensitivity analyses provided robustness to our results.

CONCLUSIONS

Our results indicated that a higher DII score was associated with an increased risk of low muscle mass among diabetes/prediabetes patients. These findings provided a nutritional strategy for diabetes/prediabetes patients to prevent skeletal muscle mass loss.

Negative association between triglyceride glucose index and BMI-adjusted skeletal muscle mass index in hypertensive adults

BACKGROUND

The triglyceride glucose (TyG) index, an indicator of insulin resistance, is often associated with adverse outcomes in various cardiovascular diseases, while hypertension is associated with an increased risk of cardiovascular diseases. As the loss of muscle mass in people with hypertension is poorly understood, the current study aimed to explore the relationship between TyG index and muscle mass in hypertensive population.

METHODS

We analyzed data from hypertensive adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. The TyG index and body mass index (BMI)-adjusted skeletal muscle mass index (SMI) were calculated and the relationship between the two was evaluated using multivariable linear regression and restricted cubic spline (RCS) regression models.

RESULTS

A total of 1633 participants in the dataset were included for the final analysis. In the multivariable regression analysis, the adjusted β of SMI with a 95% confidence interval (CI) for the highest TyG index quartile was - 5.27 (- 9.79 to - 0.75), compared with the lowest quartile. A negative linear relationship between TyG index and SMI was plotted by RCS regression (nonlinear P = 0.128). Stratified models of non-smoking women of different ages also demonstrated that SMI decreased as TyG index increased (all P for trend < 0.05).

CONCLUSION

This linear and negative correlation between TyG index and SMI in hypertensive patients suggests that insulin resistance adversely affects muscle mass.

Possible sarcopenia and risk of new-onset type 2 diabetes mellitus in older adults in China: a 7-year longitudinal cohort study

BACKGROUND

Previous studies have shown that type 2 diabetes mellitus (T2DM) can cause sarcopenia; however, these conditions may have a bidirectional association. This study aimed to explore the longitudinal association between possible sarcopenia and new-onset T2DM.

METHODS

We conducted a population-based cohort study using nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS). This study included participants aged ≥ 60 years who were free of diabetes during the baseline survey of CHARLS (2011 to 2012) and were followed up until 2018. Possible sarcopenia status was defined according to the Asian Working Group for Sarcopenia 2019 criteria. Cox proportional hazards regression models were used to evaluate the effect of possible sarcopenia on new-onset T2DM.

RESULTS

In total, 3,707 individuals were enrolled in this study, with a median age of 66 years; the prevalence of possible sarcopenia was 45.1%. During the 7-year follow-up, 575 cases (15.5%) of incident diabetes were identified. Participants with possible sarcopenia were more likely to have new-onset T2DM than those without possible sarcopenia (hazard ratio: 1.27, 95% confidence interval: 1.07-1.50; p = 0.006). In subgroup analysis, we found a significant association between possible sarcopenia and T2DM in individuals aged < 75 years or with a BMI < 24 kg/m². However, this association was not significant in individuals aged ≥ 75 years or with a BMI ≥ 24 kg/m².

CONCLUSIONS

Possible sarcopenia is associated with an increased risk of new-onset T2DM in older adults, especially in individuals who are not overweight and aged 75 years or younger.

The role of skeletal muscle mass on cardiovascular disease risk: an emerging role on modulating lipid profile

PURPOSE OF REVIEW

The purpose of this review was to present updated evidence on the role of skeletal muscle mass on cardiometabolic health.

RECENT FINDINGS

Increased lean, and especially skeletal, muscle mass has been associated with better cardiometabolic health in various epidemiological studies, even in younger age groups. In addition, the link between skeletal muscle mass and adult lipid profile is of interest. A preliminary analysis using the data from the ATTICA prospective cohort study (2002-2022) supports this association.

SUMMARY

Skeletal muscle mass has many metabolic functions (i.e., glucose, insulin and protein metabolism, mitochondrial function, arterial stiffness, inflammation, oxidative stress, brain function, hormone status). Given its associations with the lipid profile and overall cardiometabolic risk, skeletal muscle mass stands among the emerging risk factors for cardiovascular diseases. In addition to only using body mass index or fat distribution, more studies should evaluate lean mass and its prognostic and predictive ability regarding chronic diseases.

Exercise training impacts skeletal muscle remodelling induced by metabolic syndrome in ZSF1 rats through metabolism regulation

Metabolic syndrome (MetS), characterized by a set of conditions that include obesity, hypertension, and dyslipidemia, is associated with increased cardiovascular risk. Exercise training (EX) has been reported to improve MetS management, although the underlying metabolic adaptations that drive its benefits remain poorly understood. This work aims to characterize the molecular changes induced by EX in skeletal muscle in MetS, focusing on gastrocnemius metabolic remodelling. ¹H NMR metabolomics and molecular assays were employed to assess the metabolic profile of skeletal muscle tissue from lean male ZSF1 rats (CTL), obese sedentary male ZSF1 rats (MetS-SED), and obese male ZF1 rats submitted to 4 weeks of treadmill EX (5 days/week, 60 min/day, 15 m/min) (MetS-EX). EX did not counteract the significant increase of body weight and circulating lipid profile, but had an anti-inflammatory effect and improved exercise capacity. The decreased gastrocnemius mass observed in MetS was paralleled with glycogen degradation into small glucose oligosaccharides, with the release of glucose-1-phosphate, and an increase in glucose-6-phosphate and glucose levels. Moreover, sedentary MetS animals' muscle exhibited lower AMPK expression levels and higher amino acids' metabolism such as glutamine and glutamate, compared to lean animals. In contrast, the EX group showed changes suggesting an increase in fatty acid oxidation and oxidative phosphorylation. Additionally, EX mitigated MetS-induced fiber atrophy and fibrosis in the gastrocnemius muscle. EX had a positive effect on gastrocnemius metabolism by enhancing oxidative metabolism and, consequently, reducing susceptibility to fatigue. These findings reinforce the importance of prescribing EX programs to patients with MetS.

Sarcopenia negatively affects postoperative short-term outcomes of patients with non-cirrhosis liver cancer

BACKGROUND

Literature review have shown that sarcopenia substantially alters the postoperative outcomes after liver resection for malignant tumors. However, these retrospective studies do not distinguish cirrhotic and non-cirrhotic liver cancer patients, nor combine the assessment of muscle strength in addition to muscle mass. The purpose of this study is to study the relationship between sarcopenia and short-term outcomes after hepatectomy in patients with non-cirrhotic liver cancer.

METHODS

From December 2020 to October 2021, 431 consecutive inpatients were prospectively enrolled in this study. Muscle strength and mass were assessed by handgrip strength and the skeletal muscle index (SMI) on preoperative computed tomographic scans, respectively. Based on the SMI and the handgrip strength, patients were divided into four groups: group A (low muscle mass and strength), group B (low muscle mass and normal muscle strength), group C (low muscle strength and normal muscle mass), and group D (normal muscle mass and strength). The main outcome was major complications and the secondary outcome was 90-d Readmission rate.

RESULTS

After strictly exclusion, 171 non-cirrhosis patients (median age, 59.00 [IQR, 50.00-67.00] years; 72 females [42.1%]) were selected in the final analysis. Patients in group A had a statistically significantly higher incidence of major postoperative complications (Clavien-Dindo classification ≥ III) (26.1%, p = 0.032), blood transfusion rate (65.2%, p < 0.001), 90-day readmission rate (21.7%, p = 0.037) and hospitalization expenses (60,842.00 [IQR, 35,563.10-87,575.30], p < 0.001) than other groups. Sarcopenia (hazard ratio, 4.21; 95% CI, 1.44-9.48; p = 0.025) and open approach (hazard ratio, 2.56; 95% CI, 1.01-6.49; p = 0.004) were independent risk factors associated with major postoperative complications.

CONCLUSIONS

Sarcopenia is closely related to poor short-term postoperative outcomes in non-cirrhosis liver cancer patients and the assessment that combines muscle strength and muscle mass can simply and comprehensively identify it.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT04637048 . (19/11/2020).

Acceptability of a high-protein Mediterranean-style diet and resistance exercise protocol for cardiac rehabilitation patients: Involving service users in intervention design using a mixed-methods participatory approach

Background

Current cardiac rehabilitation (CR) practices focus on aerobic-style exercise with minimal nutrition advice. This approach may not be optimal for CR patients with reduced muscle mass and elevated fat mass. Higher protein, Mediterranean-style diets combined with resistance exercise (RE) may improve muscle mass and reduce the risk of future cardiovascular events, although such an approach is yet to be trialed in a CR population.

Objective

We explored patient perspectives on the proposed design of a feasibility study. Patients reflected on the acceptability of a proposed high-protein Mediterranean-style diet and RE protocol, emphasizing research methodology and the acceptability of the proposed recipes and exercises.

Design

We applied quantitative and qualitative (mixed methods) approaches. The quantitative approach involved an online questionnaire (n = 40) regarding the proposed study methodology and relevance. A subset of participants (n = 12) received proposed recipe guides and were asked to prepare several dishes and complete an online questionnaire regarding their experience. Another subset (n = 18) received links to videos of the proposed RE and completed a questionnaire regarding their impressions of them. Finally, semi-structured interviews (n = 7) were carried out to explore participants' impressions of the proposed diet and exercise intervention.

Results

Quantitative data indicated a high level of understanding of the intervention protocol and its importance within the context of this research. There was a high degree of willingness to participate in all aspects of the proposed study (>90%). The trialed recipes were enjoyed and found to be easy to make by a majority of participants (79 and 92.1%, respectively). For the proposed exercises 96.5% of responses agreed they would be willing to perform them and, 75.8% of responses agreed they would enjoy them. Qualitative analysis revealed that participants viewed the research proposal, diet, and exercise protocol in a positive light. The research materials were considered appropriate and well explained. Participants suggested practical recommendations for improving recipe guides and requested more individual-focused exercise recommendations, and more information on the specific health benefits of the diet and exercise protocols.

Conclusion

The study methodology and the specific dietary intervention and exercise protocol were found to be generally acceptable with some suggested refinements.

Sarcopenia is a risk factor for major adverse cardiac events after surgical revascularization for critical limb ischemia

OBJECTIVES

We examined the effect of sarcopenia on early surgical outcomes in patients with critical limb ischemia (CLI) in terms of major adverse cardiac events (MACE) and major adverse limb events (MALE), as well as the value of inflammatory markers of neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios (PLR) as indicators of sarcopenia in CLI patients.

METHODS

This was an observational retrospective single-center study. Patients who required surgical revascularization for CLI between October 2015 and December 2020 were identified. Psoas muscle areas were calculated from computed tomography images for psoas muscle index (PMI) calculations. Sarcopenia was defined as PMI < 5.5 cm²/m² for men and PMI < 4.0 cm²/m² for women. Risk factors for 30-day major adverse cardiac events (MACE) and major adverse limb events (MALE) were analyzed. NLR and PLR were compared between sarcopenic and non-sarcopenic patients.

RESULTS

The mean age of 217 study patients was 61.5 ± 10.9, and 16 (7.4%) patients were female. 82 (37.8%) patients were sarcopenic. Patients with sarcopenia were older (65.1 ± 9.3 vs 59.4 ± 11.2, p < .001) and history of myocardial infarction was more frequent (23.2% vs 12.6%, p = 0.042) among sarcopenic patients. Sarcopenic patients more frequently encountered MACE (9.8% vs 0.7%, p = 0.002), but not MALE. Sarcopenia increased early postoperative MACE in our cohort with an odds ratio of 11.925. NLR was not different between the two groups, while PLR was higher (127.16 vs 104.06, p = 0.010) among sarcopenic patients. The platelet-to-lymphocyte ratio of 125.11 had a sensitivity of 53.7% and a specificity of 68.1% for differentiating sarcopenia.

CONCLUSIONS

Sarcopenia was associated with more frequent 30-day MACE and perioperative mortality after revascularization for CLI. 30-day MALE was not increased in patients with sarcopenia. The use of PLR as a simple marker of sarcopenia is limited by its low sensitivity and specificity.

Bergamot (Citrus bergamia) leaf extract improves metabolic, antioxidant and anti-inflammatory activity in skeletal muscles in a metabolic syndrome experimental model

Metabolic Syndrome (MetS), inflammation and oxidative stress contribute to impairment of skeletal muscle function. Bergamot (Citrus bergamia) leaf extract (BLE) has shown protective effects against comorbidities associated with MetS through its anti-inflammatory and antioxidant effects. The aim of this work was to elucidate the antioxidant and anti-inflammatory activity of BLE in skeletal muscles in an experimental model of MetS. Once metabolic syndrome was diagnosed, animals were divided into groups receiving different treatments for 10 weeks, including control diet (n = 10), control + BLE (n = 10), High Sugar-fat diet (HSF) (n = 10), HSF + BLE (n = 10). Evaluation included nutritional, metabolic and hormonal analyses, along with measurements of inflammatory status and oxidative stress in soleus and extensor digitorum longus (EDL) muscles. BLE showed positive metabolic effects, with a reduction of plasma triglycerides and insulin resistance and an increase in high-density lipoprotein cholesterol, and protective activity against oxidative stress and inflammation in Soleus and EDL muscles in animals with MetS.

Is dynapenic abdominal obesity a risk factor for cardiovascular mortality? A competing risk analysis

BACKGROUND

Dynapenic abdominal obesity has been shown as a risk factor for all-cause mortality in older adults. However, there is no evidence on the association between this condition and cardiovascular mortality.

OBJECTIVE

We aimed to investigate whether dynapenic abdominal obesity is associated with cardiovascular mortality in individuals aged 50 and older.

METHODS

A longitudinal study with an 8-year follow-up was conducted involving 7,030 participants of the English Longitudinal Study of Ageing study. Abdominal obesity and dynapenia were respectively defined based on waist circumference (> 102 cm for men and > 88 cm for women) and grip strength (< 26 kg for men and < 16 kg for women). The sample was divided into four groups: non-dynapenic/non-abdominal obesity (ND/NAO), non-dynapenic/abdominal obesity (ND/AO), dynapenic/non-abdominal obesity (D/NAO) and dynapenic/abdominal obesity (D/AO). The outcome was cardiovascular mortality. The Fine-Grey regression model was used to estimate the risk of cardiovascular mortality as a function of abdominal obesity and dynapenia status in the presence of competing events controlled by socio-demographic, behavioural and clinical variables.

RESULTS

The risk of cardiovascular mortality was significantly higher in individuals with D/AO compared with ND/NAO (SHR 1.85; 95% CI: 1.15-2.97). D/NAO was also associated with cardiovascular mortality (SHR: 1.62; 95% CI: 1.08-2.44).

CONCLUSION

Dynapenic abdominal obesity is associated with cardiovascular mortality, with a larger effect size compared to dynapenia alone in individuals older than 50 years. Thus, prevention strategies and clinical interventions that enable mitigating the harmful effects of these conditions should be adopted to diminish such risk.

Insights into Pathogenesis, Nutritional and Drug Approach in Sarcopenia: A Systematic Review

Sarcopenia is a multifactorial condition related to the loss of muscle mass and strength due to aging, eating habits, physical inactivity, or even caused by another disease. Affected individuals have a higher risk of falls and may be associated with heart disease, respiratory diseases, cognitive impairment, and consequently an increased risk of hospitalization, in addition to causing an economic impact due to the high cost of care during the stay in hospitals. The standardization of appropriate treatment for patients with sarcopenia that could help reduce pathology-related morbidity is necessary. For these reasons, this study aimed to perform a systematic review of the role of nutrition and drugs that could ameliorate the health and quality of life of sarcopenic patients and PRISMA guidelines were followed. Lifestyle interventions have shown a profound impact on sarcopenia treatment but using supplements and different drugs can also impact skeletal muscle maintenance. Creatine, leucine, branched-chain amino acids, omega 3, and vitamin D can show benefits. Although with controversial results, medications such as Metformin, GLP-1, losartan, statin, growth hormone, and dipeptidyl peptidase 4 inhibitors have also been considered and can alter the sarcopenic's metabolic parameters, protect against cardiovascular diseases and outcomes, while protecting muscles.

Dynapenic Abdominal Obesity as a Risk Factor for Metabolic Syndrome in Individual 50 Years of Age or Older: English Longitudinal Study of Ageing

OBJECTIVES

To analyse whether dynapenic abdominal obesity is a risk factor for Metabolic syndrome (MetS) and its components in individuals 50 years of age or older.

DESIGN

A longitudinal study was conducted with an eight-year follow-up.

SETTING

Representative sample of community-dwelling participants of the English Longitudinal Study of Ageing (ELSA).

PARTICIPANTS

3,952 individuals free of MetS at baseline.

MEASUREMENTS

Dynapenic abdominal obesity was defined based on waist circumference (> 102 cm for men and > 88 cm for women) and grip strength (< 26 kg for men and < 16 kg for women). The participants were classified as non-abdominally obese/non-dynapenic (NAO/ND - reference group), abdominally obese/non-dynapenic (AO/ND), non-abdominally obese/dynapenic (NAO/D) and abdominally obese/dynapenic (AO/D). The outcome was the incidence of MetS based on the presence of three or more of the following criteria: hypertriglyceridemia, hyperglycaemia, low HDL cholesterol, arterial hypertension or body mass index ≥ 30 kg/m2 throughout eight-year follow-up. Additionally, the incidence of each component of MetS was also analyzed. Poisson regression models were run and controlled for sociodemographic, behavioural and clinical variables.

RESULTS

The mean age of the participants was 65 years and 55% were women. The prevalence of AO/ND, NAO/D and AO/D were 35.3, 4.3 and 2.2%, respectively. At the end of follow-up 558 incident cases of MetS were recorded. The adjusted model demonstrated that although abdominal obesity was a risk factor for MetS (IRR: 2.26; 95% CI: 1.87 - 2.73), the IRR was greater in AO/D individuals (IRR: 3.34; 95% CI: 2.03 - 5.50) compared with ND/NAO group. Furthermore, ND/AO was a risk factor for incidence of hypertriglyceridemia (IRR: 1.27; 95% CI: 1.06 - 1.52), hyperglycaemia (IRR: 1.41; 95% CI: 1.18 - 1.69), low HDL cholesterol (IRR: 1.70; 95% CI: 1.32 - 2.19) and BMI ≥ 30 kg/m2 (IRR: 2.58; 95% CI: 2.04 - 3.26) while D/AO was a risk factor for hyperglycaemia (IRR: 1.78; 95% CI: 1.02 - 3.10), low HDL cholesterol (IRR: 2.36; 95% CI: 1.10 - 5.08), and BMI ≥ 30 kg/m2 (IRR: 2.79; 95% CI: 1.38 - 5.62).

CONCLUSIONS

Dynapenic abdominal obesity increases the risk of MetS, with a higher IRR compared to obesity alone. The understanding of this synergic action could guide specific clinical strategies, enabling the prevention of metabolic changes that can lead to cardiovascular disease, disability and death.

The prevalence of low muscle mass associated with obesity in the USA

BACKGROUND

Sarcopenia is defined as age-related low muscle mass and function, and can also describe the loss of muscle mass in certain medical conditions, such as sarcopenic obesity. Sarcopenic obesity describes loss of muscle and function in obese individuals; however, as sarcopenia is an age-related condition and obesity can occur in any age group, a more accurate term is obesity with low lean muscle mass (OLLMM). Given limited data on OLLMM (particularly in those aged < 65 years), the purpose of this study was to estimate the prevalence of OLLMM in adults aged ≥ 20 years in the USA.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 and 1999-2006 were used. OLLMM was defined as an appendicular lean mass, adjusted for body mass index (BMI), cut-off point < 0.789 for males and < 0.512 for females, measured by dual-energy X-ray absorptiometry (DXA). DXA was only measured in individuals 20-59 years old in NHANES 2017-2018; we therefore utilized logistic regression models to predict OLLMM from NHANES 1999-2006 for those aged ≥ 60 years. The prevalence of OLLMM was estimated overall, and by sex, age, race/ethnicity, and clinical subgroup (high BMI, prediabetes, type 2 diabetes mellitus [T2DM], non-alcoholic fatty liver disease [NAFLD] with fibrosis, or post-bariatric surgery). Prevalence estimates were extrapolated to the USA population using NHANES sampling weights.

RESULTS

We estimated that, during 2017-2018, 28.7 million or 15.9% of the USA population had OLLMM. The prevalence of OLLMM was greater in older individuals (8.1%, aged 20-59 years vs 28.3%, aged ≥ 60 years), highest (66.6%) in Mexican-American females aged ≥ 60 years, and lowest (2.6%) in non-Hispanic Black males aged 20-59 years. There was a higher prevalence of OLLMM in adults with prediabetes (19.7%), T2DM (34.5%), NAFLD with fibrosis (25.4%), or post-bariatric surgery (21.8%), compared with those without each condition.

CONCLUSIONS

Overall, the burden of OLLMM in the USA is substantial, affecting almost 30 million adults. The prevalence of OLLMM increased with age, and among those with prediabetes, T2DM, NAFLD with fibrosis, or post-bariatric surgery. A unified definition of OLLMM will aid diagnosis and treatment strategies.

The Difference in the Prevalence of Metabolic Syndrome According to Meeting Guidelines for Aerobic Physical Activity and Muscle-Strengthening Exercise: A Cross-Sectional Study Performed Using the Korea National Health and Nutrition Examination Survey, 2014-2019

Physical activity and muscle strengthening are essential for preventing and managing metabolic syndrome. This study was conducted to investigate the relationship between the prevalence of metabolic syndrome and meeting the guidelines for aerobic physical activity (APA), muscle strengthening exercise (MSE), and combined exercise. We used data from 22,467 Koreans aged 40 years or older, who participated in in the Korea National Health and Nutrition Examination Survey (KNHANES) 2014-2019. We used the Global Physical Activity Questionnaire (GPAQ) to measure physical activity and surveyed frequency of MSE through a questionnaire. Metabolic syndrome was defined according to the American heart association and the National Heart, Lung, and Blood Institute. Compared with none exercise group, odds ratios of APA, MSE, and combined exercise group (CEG) on metabolic syndrome prevalence were 0.85 (95% confidence interval (CI), 0.74-0.98), 0.81 (95% CI, 0.67-0.99), and 0.65 (95% CI, 0.54-0.78) among men, respectively. Among women, ORs of APA, MSE, and CEG were 0.83 (95% CI, 0.73-0.93), 0.73 (95% CI, 0.58-0.91), and 0.74 (95% CI, 0.58-0.93), respectively. This study showed that meeting guidelines for APA and MSE was associated with lower prevalence of metabolic syndrome. Furthermore, subjects who met both APA and MSE had the lowest metabolic syndrome prevalence.

Discrimination between possible sarcopenia and metabolic syndrome using the arterial pulse spectrum and machine-learning analysis

Sarcopenia is defined as decreased skeletal muscle mass and function, and is an important cause of frailty in the elderly, also being associated with vascular lesions and poor microcirculation. The present study aimed to combine noninvasive pulse measurements, frequency-domain analysis, and machine learning (ML) analysis (1) to determine the effects on the pulse waveform induced by sarcopenia and (2) to develop discriminating models for patients with possible sarcopenia. Radial blood pressure waveform (BPW) signals were measured noninvasively for 1 min in 133 subjects who visited Tri-Service General Hospital for geriatric health checkups. They were assigned to a robust group and a possible-sarcopenia group that combined dynapenia, presarcopenia, and sarcopenia. Two classification methods were used: ML analysis and a self-developed scoring system that used 40 harmonic pulse indices as features: amplitude proportions and their coefficients of variation, and phase angles and their standard deviations. Significant differences were found in several spectral indices of the BPW between possible-sarcopenia and robust subjects. Threefold cross-validation results indicated excellent discrimination performance, with AUC equaling 0.77 when using LDA and 0.83 when using our scoring system. The present noninvasive and easy-to-use measurement and analysis method for detecting sarcopenia-induced changes in the arterial pulse transmission condition could aid the discrimination of possible sarcopenia.

Association of high body mass index, waist circumference, and body fat percentage with sarcopenia in older women

BACKGROUND

Age-related obesity and body composition changes include loss of muscle mass and increased body fat. This study aimed to investigate sex differences in the impact of sarcopenia, defined by the Asian Working Group for Sarcopenia (AWGS), on obesity in Korean older adults.

METHODS

In this 2-year longitudinal study, 3014 participants were excluded based on AWGS sarcopenia parameters (if any one of the sarcopenic parameter criteria was satisfied), including low handgrip strength (HGS), low appendicular skeletal muscle mass index (ASMI), and low short physical performance battery (SPPB). A total of 926 non-sarcopenic participants were recruited for the study. The obese and non-obese groups were compared according to the sarcopenia parameters. The following variables were selected for obesity analysis: body mass index (BMI), waist circumference (WC), and body fat percentage. Unadjusted and fully adjusted logistic regression analyses were performed for each variable to predict sarcopenia and sarcopenic obesity according to sex.

RESULTS

Among the sarcopenia parameters, reduction in ASMI was significantly lower in the obese group with high WC and percentage of body fat (PBF) in both men and women (P < 0.01). Multivariable analysis revealed that different obesity parameters were associated with AWGS criteria: women in the high BMI group presented significantly lower ASMI and sarcopenia (ASMI, OR = 0.289, 95% CI = 0.174-0.480; sarcopenia, OR = 0.152, 95% CI = 0.048-0.483). Women in the high WC group had significantly lower ASMI and sarcopenia (ASMI, OR = 0.307, 95% CI = 0.189-0.500; sarcopenia, OR = 0.262, 95% CI = 0.106-0.649). Women in the high PBF group had a lower incidence of sarcopenia (OR = 0.214, 95% CI = 0.068-0.278).

CONCLUSIONS

Our study identified that high BMI had a protective effect on the reduction of muscle mass in men and women. However, obesity parameters including BMI, WC, and PBF were positively correlated with a lower incidence of sarcopenia only in women. Obesity in older women may have a protective effect in reducing ASMI and the incidence of sarcopenia.

Determination of skeletal muscle mass by aspartate aminotransferase / alanine aminotransferase ratio, insulin and FSH in Chinese women with sarcopenia

BACKGROUND

Sarcopenia is an age-related skeletal muscle disorder that involves a loss of muscle mass or strength and physiological function. Skeletal muscle deteriorates in both quantity and quality. The endocrine system is an important regulator of muscle metabolism. Therefore, we aimed to explore the relationship between biochemical markers and muscle mass in sarcopenia.

METHODS

We used the AWGS 2014 as the diagnostic criteria for sarcopenia, considering both the loss in muscle mass, muscle strength and physical performance. A total of 2837 elderly female participants over 50 years of age from the West China Health and Aging Trend (WCHAT) study were included. Insulin, glucose, 25(OH)VD, procalcitonin, alanine aminotransferase, aspartate aminotransferase, total protein, prealbumin, albumin, thyroid-stimulating hormone, free triiodothyronine, free tetraiodothyronine, triglycerides, cholesterol, high-density lipoprotein, very low-density lipoprotein, cortisol, and follicle-stimulating hormone were measured. Based on the findings of univariate analysis, multivariate regression and receiver operating characteristic (ROC) curves were established.

RESULTS

Participants with sarcopenia had significantly lower free triiodothyronine, insulin, total protein, albumin, prealbumin, albumin/prealbumin ratio (A/G), alanine aminotransferase, triglycerides, and very low-density lipoprotein concentrations (P < 0.05). Compared with those without sarcopenia, those with sarcopenia had significantly higher free tetraiodothyronine, cortisol, follicle-stimulating hormone (FSH), aspartate aminotransferase/alanine aminotransferase ratio (AST/ALT), and high-density lipoprotein concentrations (P < 0.05). Insulin (OR = 0.854), FSH (OR = 1.016), and the AST/ALT ratio (OR = 1.819) were independent risk factors for low muscle mass (P < 0.001). The AUC of insulin was the highest, followed by the AST/ALT ratio and FSH (0.691, 0.671, and 0.634, respectively), and the AUC of the mixture of the above three reached 0.736.

CONCLUSION

In this cross-sectional study of elderly Chinese females aged over 50 years from the WCHAT, FSH, insulin, and AST/ALT ratio were associated with sarcopenia and risk factors for low muscle mass.

The effects of voluntary binge-patterned ethanol ingestion and daily wheel running on signaling of muscle protein synthesis and degradation in female mice

Excessive ethanol ingestion can reduce skeletal muscle protein synthesis (MPS) through the disruption of signaling along the Akt-mTOR pathway and increase muscle protein degradation (MPD) through the Ubiquitin Proteasome Pathway (UPP) and autophagy. Identification of interventions that curb the disrupting effects of alcohol misuse on MPS and MPD are of central importance for the prevention of chronic health complications that arise from muscle loss. Physical activity is one potential strategy to combat the deleterious effects of alcohol on skeletal muscle. Therefore, the purpose of this study was to investigate the interaction between daily wheel running and binge-patterned ethanol consumption, through episodes of voluntary binge-patterned ethanol drinking, on signaling factors along the Akt-mTOR, Ubiquitin-Proteasome, and autophagy pathways. Adult female C57BL/6J mice received daily access to cages with or without running wheels for 2.5 h/day for five weeks. During the final five days of the study, mice received 2-4 h of daily access to sipper tubes containing water (n = 14 sedentary; n = 15 running) or 20% ethanol (n = 14 sedentary; n = 16 running) 30 min after running wheel access, using the "Drinking in the Dark" (DID) model of binge-patterned ethanol consumption. Immediately after the final episode of DID, gastrocnemius muscle was extracted. Western blotting was performed to measure proteins along Akt-mTOR, Ubiquitin-Proteasome, and autophagy pathways, and PCR was used to assess mRNA expression of atrogenes. Ethanol access increased expression of MAFbx by 82% (p = 0.048), but did not robustly influence Akt-mTOR or UPP signaling. Daily wheel access did not prevent alcohol-induced MAFbx expression; however, ethanol access decreased the phosphorylation of p70S6K by 45% in running mice (p = 0.020). These results suggest that physical activity may be insufficient to prevent alcohol-induced changes to signaling factors along pathways involved in muscle loss. Instead, binge-patterned ethanol ingestion may impair the benefits of physical activity on factors involved in MPS.

Metabolic Disorders in Menopause

Menopause is an aging process and an important time equivalent to one-third of a woman's lifetime. Menopause significantly increases the risk of cardiometabolic diseases, such as obesity, type 2 diabetes, cardiovascular diseases, non-alcoholic liver disease (NAFLD)/metabolic associated fatty liver disease (MFFLD), and metabolic syndrome (MetS). Women experience a variety of symptoms in the perimenopausal period, and these symptoms are distressing for most women. Many factors worsen a woman's menopausal experience, and controlling these factors may be a strategy to improve postmenopausal women's health. This review aimed to confirm the association between menopause and metabolic diseases (especially MetS), including pathophysiology, definition, prevalence, diagnosis, management, and prevention.

Sarcopenia and Chronic Complications of Type 2 Diabetes Mellitus

Sarcopenia, defined as the loss of skeletal muscle mass and strength and/or a decrease in physical performance, is classically related to aging. However, chronic disease, including type 2 diabetes mellitus (T2DM), may accelerate the development of sarcopenia. Previous studies found strong association between T2DM and sarcopenia. Insulin resistance that exists in T2DM is thought to be the key mediator for impaired physical function and mobility which may lead to sarcopenia. T2DM may cause sarcopenia through the mediation of insulin resistance, inflammation, accumulation of advanced glycation end-products, and oxidative stress that may affect muscle mass and strength, protein metabolism, and vascular and mitochondrial dysfunction. On the other hand, loss of muscle in sarcopenia may play a role in the development of T2DM through the decreased production of myokines that play a role in glucose and fat metabolism. This review highlights the findings of existing literature on the relationship between T2DM and sarcopenia which emphasize the pathophysiology, chronic vascular complications, and the course of macrovascular and microvascular complications in T2DM.

Prognostic Impact of Myosteatosis on Mortality in Hospitalized Patients with COVID-19

Body composition, including sarcopenia, adipose tissue, and myosteatosis, is associated with unfavorable clinical outcomes in patients with coronavirus disease (COVID-19). However, few studies have identified the impact of body composition, including pre-existing risk factors, on COVID-19 mortality. Therefore, this study aimed to evaluate the effect of body composition, including pre-existing risk factors, on mortality in hospitalized patients with COVID-19. This two-center retrospective study included 127 hospitalized patients with COVID-19 who underwent unenhanced chest computed tomography (CT) between February and April 2020. Using the cross-sectional CT images at the L2 vertebra level, we analyzed the body composition, including skeletal muscle mass, visceral to subcutaneous adipose tissue ratio (VSR), and muscle density using the Hounsfield unit (HU). Of 127 patients with COVID-19, 16 (12.6%) died. Compared with survivors, non-survivors had low muscle density (41.9 vs. 32.2 HU, p < 0.001) and high proportion of myosteatosis (4.5 vs. 62.5%, p < 0.001). Cox regression analyses revealed diabetes (hazard ratio [HR], 3.587), myosteatosis (HR, 3.667), and a high fibrosis-4 index (HR, 1.213) as significant risk factors for mortality in patients with COVID-19. Myosteatosis was associated with mortality in hospitalized patients with COVID-19, independent of pre-existing prognostic factors.

Sarcopenia, healthy living, and mortality in patients with chronic liver diseases

Chronic liver diseases (CLDs) are associated with increased morbidity and mortality. Sarcopenia is an important complication of CLD that can be impacted by several modifiable risk factors. Our aim was to assess the associations between healthy living, sarcopenia, and long-term outcomes among patients with CLD. We used the Third National Health and Nutrition Examination Survey data with National Death Index-linked mortality files. We used the American Heart Association's Life's Simple 7 (LS7) metrics as surrogates of healthy living. The study included 12,032 subjects (34.9% CLDs [0.5% hepatitis B virus (HBV), 1.8% hepatitis C virus (HCV), 5.7% alcohol-associated liver disease (ALD), 26.9% nonalcoholic fatty liver disease (NAFLD)] and 65.1% controls). Prevalence of sarcopenia was higher among NAFLD than other CLDs and the controls (40.7% in NAFLD, 27.2% in ALD, 22.4% in HCV, 16.8% in HBV, and 18.5% in controls; p < 0.001). Among NAFLD and ALD, patients with sarcopenia were less likely to meet ideal LS7 metrics than those without sarcopenia. During 27 years of follow-up, among 4 patients with CLDs and the controls, all-cause cumulative mortality was highest among patients with HCV (35.2%), followed by ALD (34.7%) and NAFLD (29.6%). The presence of sarcopenia was associated with higher risk of all-cause mortality only among subjects with NAFLD (hazard ratio [HR] 1.24; 95% confidence interval [CI] 1.01-1.54; p = 0.04). Among subjects with NAFLD, presence of sarcopenia was associated with higher risk of cardiovascular-specific (HR 2.28 [1.71-3.05; p < 0.01]), cancer-specific (HR 1.90 [1.37-2.65]; p < 0.01), diabetes-specific (HR 6.42 [2.87-14.36]; p < 0.01), and liver-specific mortality (HR 2.49 [1.08-5.76]; p = 0.04). The multivariable model showed that component of LS7 metrics that provided the strongest protection against sarcopenia were ideal body mass index, ideal blood pressure, ideal physical activity, and ideal glycemic control among subjects with NAFLD subjects. Conclusions: Among subjects with NAFLD, sarcopenia is associated with a higher risk of all-cause mortality and liver mortality. Attainment of ideal LS7 metrics provides protection against sarcopenia in NAFLD.