Endocrine determinants of incident sarcopenia in middle-aged and elderly European men

Sarcopenic obesity and reduced BMD in young men living with HIV: body composition and sex steroids interplay

PURPOSE

Sex steroids play a key role on male bone homeostasis and body composition (BC), their role in men living with HIV (MLWH) is less recognized. This study aimed at investigating the prevalence of low BMD, sarcopenia, and sarcopenic obesity (SO) and their relationship with sex steroids in MLWH aged < 50.

METHODS

Prospective, cross-sectional, observational study on MLWH younger than 50 (median age 47.0 years). BC and BMD were evaluated with DXA. Two different definitions of sarcopenia were applied: appendicular lean mass/height2 (ALMI) < 7.26 kg/m2 or appendicular lean mass/body weight (ALM/W) < 28.27%. Low BMD was defined for Z-score < -2.0. Sarcopenia coupled with obesity identified SO. Serum total testosterone (T) and estradiol (E2) were measured by LC-MS/MS; free testosterone (cFT) was calculated by Vermeulen equation.

RESULTS

Sarcopenia was detected in 107 (34.9%) and 44 (14.3%) out of 307 MLWH according to ALMI and ALM/W, respectively. The prevalence of SO was similar by using both ALMI (11.4%) and ALM/W (12.4%). Sarcopenic and SO MLWH had lower total T and cFT in both the definition for sarcopenia. BMD was reduced in 43/307 (14.0%). Serum E2 < 18 pg/mL was an independent contributing factor for sarcopenia, SO, and low BMD.

CONCLUSIONS

T and E2 are important determinants of BC even in MLWH. This is among the first studies investigating the distribution of obesity phenotypes and the prevalence of SO among MLWH showing that SO is present in 11-12% of enrolled MLWH regardless of the definition used. However, deep differences emerged using two different diagnostic definitions.

Influence of Sugar-Sweetened Beverages Intake on Sarcopenic Obesity, Visceral Obesity, and Sarcopenia in Lebanese Patients with MASLD: A Case-Control Study

Chronic liver diseases are a major global health concern.

AIMS

this study investigated the links between medical, clinical, anthropometric, and dietary factors with dysfunction-associated steatotic liver disease (MASLD) in the Lebanese population using a case-control approach to uncover factors influencing visceral obesity, sarcopenia, and sarcopenic obesity.

METHODS AND MATERIALS

a total of 120 participants (20-70 years old) were divided into case and control groups based on liver disease diagnosis. Patient information was gathered through a questionnaire encompassing demographics, medical history, and beverage consumption. Anthropometric and body composition data were collected in a clinical setting.

RESULTS

our findings indicated a clear association between the presence of MASLD and obesity, hypertension, and diabetes. The positive association with higher body mass index and all three conditions remained consistent even when data was stratified by case and control groups. A greater proportion of MASLD patients exhibited sarcopenic obesity. Furthermore, MASLD cases showed higher consumption of sugary beverages and a reduced intake of milk and water in their diets.

CONCLUSIONS

this study shed light on the health attributes and diets of the Lebanese population with liver diseases and suggested more research in this area and in a more ethnically diverse population.

Therapeutic Consequences of Targeting the IGF-1/PI3K/AKT/FOXO3 Axis in Sarcopenia: A Narrative Review

The high prevalence of sarcopenia in an aging population has an underestimated impact on quality of life by increasing the risk of falls and subsequent hospitalization. Unfortunately, the application of the major established key therapeutic-physical activity-is challenging in the immobile and injured sarcopenic patient. Consequently, novel therapeutic directions are needed. The transcription factor Forkhead-Box-Protein O3 (FOXO3) may be an option, as it and its targets have been observed to be more highly expressed in sarcopenic muscle. In such catabolic situations, Foxo3 induces the expression of two muscle specific ubiquitin ligases (Atrogin-1 and Murf-1) via the PI3K/AKT pathway. In this review, we particularly evaluate the potential of Foxo3-targeted gene therapy. Foxo3 knockdown has been shown to lead to increased muscle cross sectional area, through both the AKT-dependent and -independent pathways and the reduced impact on the two major downstream targets Atrogin-1 and Murf-1. Moreover, a Foxo3 reduction suppresses apoptosis, activates satellite cells, and initiates their differentiation into muscle cells. While this indicates a critical role in muscle regeneration, this mechanism might exhaust the stem cell pool, limiting its clinical applicability. As systemic Foxo3 knockdown has also been associated with risks of inflammation and cancer progression, a muscle-specific approach would be necessary. In this review, we summarize the current knowledge on Foxo3 and conceptualize a specific and targeted therapy that may circumvent the drawbacks of systemic Foxo3 knockdown. This approach presumably would limit the side effects and enable an activity-independent positive impact on skeletal muscle.

Exploring traditional Chinese medicine as a potential treatment for sarcopenia: A network pharmacology and data mining analysis of drug selection and efficacy

Sarcopenia, as an increasingly pressing clinical issue, can be ameliorated through employment of traditional Chinese medicines. However, the current lack of specific pharmacological interventions for Sarcopenia necessitates further exploration of novel possibilities in traditional Chinese medicine for the treatment of this condition, utilizing advanced methodologies such as web pharmacology and data mining. Screening the essential targets of Sarcopenia, conducting matching between target and active molecules, as well as active molecules and herbs. Employing data mining techniques to analyze the screening outcomes, and molecular docking to compare the binding activities of active molecules with target proteins. The approach of using herbs for the treatment of Sarcopenia involves 13 targets, with 414 active compounds and 367 types of herbs. Data mining reveals that the herbs used in treating Sarcopenia are primarily characterized by their bitter taste, exerting their effects through dispelling dampness and promoting blood circulation. Moreover, 2 new formulas are postulated. Furthermore, molecular docking analysis indicates that the main active components of the herbs can be observed to tightly bind with the targets. Through network pharmacology and molecular docking, our findings reveal that herbs contain 15 key active components and 5 key targets, which correspond to 7 major herbs and 2 new formulas. Academically, these findings hold significant reference value for the development of novel drugs targeting Sarcopenia.

Relationship between hypovitaminosis D and sarcopenia in patients with stage 3 and 4 chronic kidney disease in Colombian patients

BACKGROUND

Sarcopenia is a condition associated with aging and multiple medical conditions such as CKD and hypovitaminosis D.

METHODS

An observational cross-sectional study was carried out, based on patients registered in a database of specialized nephrology consultation in the city of Manizales, Colombia. 101 patients over 18 years of age who had stage 3 or 4 CKD were included.

RESULTS

The frequency of sarcopenia was 10.9%. No relationship was found between sarcopenia alone and serum vitamin D levels. However, when sarcopenia was categorized as severe there was a direct relationship with hypovitaminosis D. There was also a direct relationship between dynapenia and hypovitaminosis D. In addition, patients who had serum vitamin D levels above 40 ng/ml had better muscle performance, and, consequently, probably a lower risk of frailty.

CONCLUSION

When patients, within their treatment, received vitamin D supplementation, no effect on muscle performance was observed.

Sarcopenia, osteoporosis and frailty

Muscles and bones are intricately connected tissues displaying marked co-variation during development, growth, aging, and in many diseases. While the diagnosis and treatment of osteoporosis are well established in clinical practice, sarcopenia has only been classified internationally as a disease in 2016. Both conditions are associated with an increased risk of adverse health outcomes such as fractures, dysmobility and mortality. Rather than focusing on one dimension of bone or muscle mass or weakness, the concept of musculoskeletal frailty captures the overall loss of physiological reserves in the locomotor system with age. The term osteosarcopenia in particular refers to the double jeopardy of osteoporosis and sarcopenia. Muscle-bone interactions at the biomechanical, cellular, paracrine, endocrine, neuronal or nutritional level may contribute to the pathophysiology of osteosarcopenia. The paradigm wherein muscle force controls bone strength is increasingly facing competition from a model centering on the exchange of myokines, osteokines and adipokines. The most promising results have been obtained in preclinical models where common drug targets have been identified to treat these conditions simultaneously. In this narrative review, we critically summarize the current understanding of the definitions, epidemiology, pathophysiology, and treatment of osteosarcopenia as part of an integrative approach to musculoskeletal frailty.

Can artificial intelligence simplify the screening of muscle mass loss?

Background

Sarcopenia is a risk factor for morbidity and preventable mortality in old age, with consequent high costs for the national health system. Its diagnosis requires costly radiological examinations, such as the DEXA, which complicate screening in medical centers with a high prevalence of sarcopenia.

Objectives

Developing a nearly zero-cost screening tool to emulate the performance of DEXA in identifying patients with muscle mass loss. This can crucially help the early diagnosis of sarcopenia at large-scale, contributing to reduce its prevalence and related complications with timely treatments.

Methods

We exploit cross-sectional data for about 14,500 patients and 38 non-laboratory variables from successive NHANES over 7 years (1999-2006). Data are analyzed through a state-of-the-art artificial intelligence approach based on decision trees.

Results

A reduced number of anthropometric parameters allows to predict the outcome of DEXA with AUC between 0.92 and 0.94. The most complex model derived in this paper exploits 6 variables, related to the circumference of key corporal segments and to the evaluation of body fat. It achieves an optimal trade-off sensitivity of 0.89 and a specificity of 0.82. Restricting exclusively to variables related to lower limb, we obtain an even simpler tool with only slightly lower accuracy (AUC 0.88-0.90).

Conclusions

Anthropometric data seem to contain the entire informative content of a more complex set of non-laboratory variables, including anamnestic and/or morbidity factors. Compared to previously published screening tools for muscle mass loss, the newly developed models are less complex and achieve a better accuracy. The new results might suggest a possible inversion of the standard diagnostic algorithm of sarcopenia. We conjecture a new diagnostic scheme, which requires a dedicated clinical validation that goes beyond the scope of the present study.

Prevalence of sarcopenia and its association with clinical outcomes in heart failure: An updated meta-analysis and systematic review

BACKGROUND

Sarcopenia is thought to be strongly associated with heart failure, but meta-analyses with sufficient samples are still lacking to accurately address its clinical situation.

HYPOTHESIS

Sarcopenia has a high prevalence in patients with heart failure and is closely related to adverse clinical outcomes.

METHODS

Relevant databases were systematically searched in October 2021 and updated in July 2022. The data with high heterogeneity were combined with random effects model.

RESULTS

Twenty-one studies with 68,556 HF patients were included. The combined prevalence of sarcopenia in HF patients was 31%. Subgroup analysis found that the prevalence of sarcopenia in HF patients was 35% in Asia, 31% in Europe, 25% in the Americas, 31% in people aged ≥65 years, 25% in people with age <65 years, 28% in HF with reduced ejection fraction (HFrEF) patients and 18% in HF with preserved ejection fraction (HFpEF) patients. In addition, our analysis shows that sarcopenia in patients with HF is associated with an increased risk of poor prognosis, with a combined hazard ratio [HR] of 1.64 (95% confidence interval [CI] = 1.20-5.25), sarcopenia was also associated with poor outcomes in HFrEF patients with pooled HR of 2.77 (95% CI = 1.29-5.95). However, it was not associated with poor outcomes in HFpEF patients with pooled HR of 1.61 (95% CI = 0.82-3.16).

CONCLUSIONS

The prevalence of sarcopenia is high in HF patients, and patients with HF, particularly those with reduced ejection fraction, are at high risk of adverse outcomes from sarcopenia. Therefore, early identification and intervention for sarcopenia were beneficial for improving the prognosis of HF patients.

Sarcopenia prevalence and incidence in older men - a MrOs Sweden study

INTRODUCTION

The European Working Group on Sarcopenia in Older People (EWGSOP) published a revised definition of sarcopenia in 2018. There are few incidence studies of sarcopenia following the latest definition.

OBJECTIVE

To study prevalence, incidence proportion and incidence rate of sarcopenia in a simple random sample of older Swedish men using the EWGSOP2 definition.

METHODS

Men aged 69-81 were invited to participate in the Osteoporotic Fractures in Men (MrOs) Sweden study. Of 2,004 included participants, 1,266 participants (mean age 75.1, SD 3.1 years) completed baseline and 5-year follow-up measurements. We assessed muscle strength by measuring grip strength and chair stands test, lean mass by dual energy X-ray absorptiometry and physical performance by gait speed at baseline and follow-up. Sarcopenia prevalence and incidence were calculated according to the EWGSOP2 definition.

RESULTS

Sarcopenia prevalence increased from 5.6% at baseline to 12.0% at follow-up. During the mean 5.2-year follow-up period, 9.1% developed sarcopenia (incidence proportion), corresponding to an incidence rate of 1.8 per 100 person-years at risk while 39.4% of the participants with sarcopenia at baseline participating in follow-up reversed to no longer having confirmed sarcopenia at 5-year follow-up.

CONCLUSION

The prevalence of sarcopenia defined along EWGSOP2 criteria doubled within 5 years in older men, and more than a third of the study participants with sarcopenia at baseline did not have sarcopenia at follow-up. We conclude that sarcopenia is not a static condition.

Brachial-Ankle Pulse Wave Velocity Mediates the Association between Increased Age and Risk of Sarcopenia among Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND AND AIMS

Arterial stiffness and sarcopenia are commonly seen in patients with type 2 diabetes mellitus (T2DM), and both are age-related diseases. However, few studies have addressed the causal relationship between age, arterial stiffness, and sarcopenia, especially in patients with T2DM. This study is aimed at investigating the relationship among age, arterial stiffness, and sarcopenia in patients with T2DM.

METHODS AND RESULTS

This cross-sectional study enrolled 557 inpatients with diabetes at the First Affiliated Hospital of Wenzhou Medical University, China, between June 2020 and July 2021. Patients who were diagnosed with T2DM and underwent examination of dual-energy X-ray absorptiometry, handgrip strength, 6-meter walk speed, and brachial-ankle pulse wave velocity (baPWV, a recognized indicator of arterial stiffness) were enrolled. A total of 447 patients were included. A dose-dependent relationship was found between age and sarcopenia. We also found a dose-dependent relationship between age and baPWV. Similarly, significant dose-dependent relationships were found across baPWV tertiles with higher prevalence of sarcopenia. Then, a mediation analysis was performed to explore the mediation effect of arterial stiffness on age-associated sarcopenia. We found that the prevalence of sarcopenia increased by 0.0115 (95% CI, 0.0028-0.0239) per 1 year increase in age by the mediation effect of baPWV and that the direct effect of aging on sarcopenia was 0.0441 (95% CI, 0.0101-0.0909) per 1 year older. baPWV mediated 20.5% of the positive relationship between increased age and the prevalence of sarcopenia.

CONCLUSIONS

Elevated baPWV partially mediates the association of age and sarcopenia among patients with T2DM.

Organokines, Sarcopenia, and Metabolic Repercussions: The Vicious Cycle and the Interplay with Exercise

Sarcopenia is a disease that becomes more prevalent as the population ages, since it is directly linked to the process of senility, which courses with muscle atrophy and loss of muscle strength. Over time, sarcopenia is linked to obesity, being known as sarcopenic obesity, and leads to other metabolic changes. At the molecular level, organokines act on different tissues and can improve or harm sarcopenia. It all depends on their production process, which is associated with factors such as physical exercise, the aging process, and metabolic diseases. Because of the seriousness of these repercussions, the aim of this literature review is to conduct a review on the relationship between organokines, sarcopenia, diabetes, and other metabolic repercussions, as well the role of physical exercise. To build this review, PubMed-Medline, Embase, and COCHRANE databases were searched, and only studies written in English were included. It was observed that myokines, adipokines, hepatokines, and osteokines had direct impacts on the pathophysiology of sarcopenia and its metabolic repercussions. Therefore, knowing how organokines act is very important to know their impacts on age, disease prevention, and how they can be related to the prevention of muscle loss.

Development and Verification of a Combined Diagnostic Model for Sarcopenia with Random Forest and Artificial Neural Network

Background

Sarcopenia is a chronic disease characterized by an age-related decline in skeletal muscle mass and function, and diagnosis is challenging owing to the lack of a clear “gold standard” assessment method.

Objective

This study is aimed at combining random forest (RF) and artificial neural network (ANN) methods to screen key potential biomarkers and establish an early sarcopenia diagnostic model.

Methods

Three gene expression datasets were downloaded and merged by searching the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in the merged dataset were identified by R software and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Afterward, the STRING database was employed for interaction analysis of the differentially encoded proteins. Then, RF was used to identify key genes from the DEGs, and a sarcopenia diagnostic model was constructed by ANN. Finally, the diagnostic model was assessed using a validation dataset, while its diagnostic performance was evaluated by the area under curve (AUC) value.

Results

107 sarcopenia-related DEGs were identified, and they were mainly enriched in the FoxO and AMPK signaling pathways involved in the molecular pathogenesis of sarcopenia. Thereafter, seven key genes (MT1X, FAM171A1, ZNF415, ARHGAP36, CISD1, ETNPPL, and WISP2) were identified by the RF classifier. The proteins encoded by three of these genes (CISD1, ETNPPL, and WISP2) may be potential biomarkers for sarcopenia. Finally, a diagnostic model for sarcopenia was successfully designed by ANN, achieving an AUC of 0.999 and 0.85 in the training and testing datasets, respectively.

Conclusion

We identified several potential genetic biomarkers and successfully developed an early predictive model with high diagnostic performance for sarcopenia. Moreover, our results provide a valuable reference for the early diagnosis and screening of sarcopenia in the future.

Serum IGF-1 levels are associated with sarcopenia in elderly men but not in elderly women

BACKGROUND

Sarcopenia is an age-associated decline in muscle mass that negatively affects the metabolic rate, strength, and function of the body and ultimately leads to a decrease in quality of life. Insulin-like growth factor 1 (IGF-1) is a modulator of muscle mass and muscle function. There is evidence that IGF-1 is related to the appendicular skeletal muscle mass index (ASMI) and grip strength. The aim of this study was to explore the relationship between serum IGF-1 levels and sarcopenia in older people.

METHODS

In this cross-sectional survey of 984 people older than 60 years old, we used the 2019 criteria of the Asian Working Group for Sarcopenia (AWGS) to define sarcopenia. We collected demographic variables, measured ASMI and grip strength, and detected serum IGF-1 data. The levels of serum IGF-1 were separated into quintiles (Q1-Q5).

RESULTS

Adjusted for age, education level, smoking, number of diseases and BMI, the multivariable linear regression analysis revealed that serum IGF-1 levels were related to ASMI in elderly men (coefficient = 0.03, 95% CI = 0.02-0.05, P < 0.001) but were not related to their grip strength. There was no significant relationship between serum IGF-1 levels and ASMI or grip strength in elderly women. The multivariable log-binomial regression analysis showed that higher serum IGF-1 levels were associated with a lower prevalence of sarcopenia in elderly men (prevalence ratio (PR) = 0.99, 95% CI = 0.98-1.00, P < 0.05) but not in elderly women.

CONCLUSION

Serum IGF-1 levels were highly correlated with sarcopenia in older men. Further studies are needed to further explore the possible reasons for the observed difference between genders. Serum IGF-1 might predict sarcopenia prevalence in elderly men.

Nitric-Oxide-Inducing Factors on Vitamin D Changes in Older People Susceptible to Suffer from Sarcopenia

Calcium and magnesium, together with vitamin D and the hormones testosterone and cortisol, are key elements in muscle function, to maintain physical fitness. This study aims to analyze if supplementation with NO precursors (L-arginine, L-citrulline and beetroot extract) modulates the circulating levels of calcium, magnesium, vitamin D and steroid hormones in elders. Sixty-one volunteers (65.1 years old, 164.6 cm of height and 71.2 kg of weight) susceptible to develop sarcopenia participated in a physical activity program for 6 weeks. Participants were divided into four groups: one placebo and three taking one of the indicated supplements. Physical capacity was assessed through the following tests: (a) distance covered in 6 min by walking (endurance indicator); (b) hand grip (upper-body strength indicator); (c) time to cover 4 m by walking (speed indicator); and (d) time to perform five full squats (lower-body strength indicator). We concluded that there is a disparity in the association of steroid hormones, vitamin D levels and physical fitness. However, a significant inverse correlation between speed and endurance indicators was observed. Higher circulating vitamin D levels were observed in the L-arginine- and beetroot-supplemented groups. In conclusion, vasodilators increase vitamin D circulating levels that, in the long term, could maintain mineral homeostasis, improving muscular function.

Biomarker Changes in Response to a 12-Week Supplementation of an Oral Nutritional Supplement Enriched with Protein, Vitamin D and HMB in Malnourished Community Dwelling Older Adults with Sarcopenia

Malnutrition and sarcopenia commonly overlap and contribute to adverse health outcomes. Previously, chronic supplementation with two oral nutritional supplements (ONS), control (C_ONS) and experimental ONS enriched with protein, vitamin D and β-hydroxy β-methylbutyrate (HMB) (E_ONS), improved muscle strength and quality in malnourished sarcopenic older adults, with E_ONS demonstrating early strength benefits at 12 weeks. To understand the underlying biological mechanisms contributing to the observed early strength benefits of E_ONS, we examined serum biomarker changes in response to 12-week supplementation. Serum samples (E_ONS (n = 90) and C_ONS (n = 103)) collected at baseline and 12 weeks were analyzed. Biomarkers (n = 243) were measured using multiplexed immunoassay, commercial immunoassays and ELISAs. Sixty markers were excluded with levels below assay detection limits. Sixteen biomarkers significantly changed in response to both interventions including nutritional and metabolic markers. Thirteen biomarkers significantly changed in response to E_ONS but not C_ONS. Increases in immunoglobulins, myoglobin, total protein, vitamin E and magnesium were observed with E_ONS. Inflammation-related ferritin and osteopontin decreased, while soluble receptors for cytokines increased, suggesting decreased inflammation. Sex hormone-binding globulin associated with sarcopenia also decreased with E_ONS. Biomarkers reflective of multiple biological systems were impacted by nutritional intervention in sarcopenic older adults. Incremental biomarker changes were observed in response to E_ONS containing HMB that possibly link to improvements in skeletal muscle health.

l-Arginine and Beetroot Extract Supplementation in the Prevention of Sarcopenia

Aging is associated with a significant decline in neuromuscular function, leading to a reduction in muscle mass and strength. The aim of the present report was to evaluate the effect of supplementation with nitric oxide precursors (l-arginine and beetroot extract) in muscular function during a training period of 6 weeks in elderly men and women. The study (double-blind, placebo-controlled) involved 66 subjects randomly divided into three groups: placebo, arginine-supplemented and beetroot extract-supplemented. At the end of this period, no changes in anthropometric parameters were observed. Regarding other circulating parameters, urea levels were significantly (p < 0.05) lower in women of the beetroot-supplemented group (31.6 ± 5.9 mg/dL) compared to placebo (41.3 ± 8.5 mg/dL) after 6 weeks of training. In addition, the circulating creatine kinase activity, as an index of muscle functionality, was significantly (p < 0.05) higher in women of the arginine- (214.1 ± 162.2 mIU/L) compared to the beetroot-supplemented group (84.4 ± 36.8 mIU/L) at the end of intervention. No significant effects were noticed with l-arginine or beetroot extract supplementation regarding strength, endurance and SPPB index. Only beetroot extract supplementation improved physical fitness significantly (p < 0.05) in the sprint exercise in men after 6 weeks (2.33 ± 0.59 s) compared to the baseline (2.72 ± 0.41 s). In conclusion, beetroot seems to be more efficient during short-term training while supplementing, preserving muscle functionality in women (decreased levels of circulating creatine kinase) and with modest effects in men.

Sexual Dimorphism in Transcriptional and Functional Glucocorticoid Effects on Mouse Skeletal Muscle

Muscle atrophy is common in patients with increased glucocorticoid exposure. Glucocorticoid effects are often sex-specific, and while different glucocorticoid responses between male and female subjects are reported, it is unclear why this is. In this study, we evaluated the effects of corticosterone and synthetic glucocorticoid treatment on muscle atrophy in male and female mice. We found that corticosterone treatment reduced grip strength in female mice only, whereas muscle mass was reduced in both sexes. Skeletal muscle transcriptional responses to corticosterone treatment were more pronounced and widespread in male mice. Synthetic glucocorticoid treatment reduced grip strength in both sexes, while female mice were more sensitive to muscle atrophy than male mice. To evaluate the role of androgens, chemically-castrated male mice were treated with synthetic glucocorticoids. We observed additively reduced muscle mass, but did not observe any interaction effects. Although sex differences in glucocorticoid responses in skeletal muscle are partly influenced by androgen signaling, further studies are warranted to fully delineate the underlying mechanisms.

Mitochondrial Quality Control in Sarcopenia: Updated Overview of Mechanisms and Interventions

Sarcopenia is a common geriatric disorder characterized by decreased muscle strength, low muscle mass and poor physical performance. This aging-related skeletal muscle deterioration leads to adverse outcomes and severely impairs the quality of life of patients. The accumulation of dysfunctional mitochondria with aging is an important factor in the occurrence and progression of sarcopenia. Mitochondrial quality control (MQC) fundamentally ensures the normal mitochondrial functions and is comprised of four main parts: proteostasis, biogenesis, dynamics and autophagy. Therefore, any pathophysiologic factors compromising the quality control of homeostasis in the skeletal muscle may lead to sarcopenia. However, the specific theoretical aspects of these processes have not been fully elucidated. Current therapeutic interventions using nutritional and pharmaceutical treatments show a modest therapeutic efficacy; however, only physical exercise is recommended as the first-line therapy for sarcopenia, which can ameliorate skeletal muscle deficiency by maintaining the homeostatic MQC. In this review, we summarized the known mechanisms that contribute to the pathogenesis of sarcopenia by impairing normal mitochondrial functions and described potential interventions that mitigate sarcopenia through improving MQC.

A Novel Clinical-Radiomics Model Based on Sarcopenia and Radiomics for Predicting the Prognosis of Intrahepatic Cholangiocarcinoma After Radical Hepatectomy

Background

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive malignant tumor with a poor prognosis. This study aimed to establish a novel clinical-radiomics model for predicting the prognosis of ICC after radical hepatectomy.

Methods

A clinical-radiomics model was established for 82 cases of ICC treated with radical hepatectomy in our hospital from May 2011 to December 2020. Radiomics features were extracted from venous-phase and arterial-phase images of computed tomography. Kaplan-Meier survival analysis was generated to compare overall survival (OS) between different groups. The independent factors were identified by univariate and multivariate Cox regression analyses. Nomogram performance was evaluated regarding discrimination, calibration, and clinical utility. C-index and area under the curve (AUC) were utilized to compare the predictive performance between the clinical-radiomics model and conventional staging systems.

Results

The radiomics model included five features. The AUC of the radiomics model was 0.817 in the training cohort, and 0.684 in the validation cohort. The clinical-radiomics model included psoas muscle index, radiomics score, hepatolithiasis, carcinoembryonic antigen, and neutrophil/lymphocyte ratio. The reliable C-index of the model was 0.768, which was higher than that of other models. The AUC of the model for predicting OS at 1, and 3 years was 0.809 and 0.886, which was significantly higher than that of the American Joint Committee on Cancer 8^th staging system (0.594 and 0.619), radiomics model (0.743 and 0.770), and tumor differentiation (0.645 and 0.628). After stratification according to the constructed model, the median OS was 59.8 months for low-risk ICC patients and 10.1 months for high-risk patients (p < 0.0001).

Conclusion

The clinical-radiomics model integrating sarcopenia, clinical features, and radiomics score was accurate for prognostic prediction for mass-forming ICC patients. It provided an individualized prognostic evaluation in patients with mass-forming ICC and could helped surgeons with clinical decision-making.

Inflammatory markers are associated with quality of life, physical activity, and gait speed but not sarcopenia in aged men (40-79 years)

BACKGROUND

Age-related chronic low-grade inflammation (inflammaging) is one of the proposed mechanisms behind sarcopenia. However, findings regarding inflammatory markers in sarcopenic older adults are conflicting. This study aimed to determine the association between inflammatory markers, prevalent as well as incident sarcopenia, sarcopenia-defining parameters, quality of life (QoL), and physical activity in middle-aged and older men.

METHODS

Men aged 40-79 years (mean 59.66 ± 11.00y) were recruited from population registers in eight European centres for participation in the European Male Aging study (EMAS). Subjects were assessed at baseline (2003-2005) and again after a median follow-up of 4.29 years. In 2577 participants, associations between baseline inflammatory markers [high-sensitive C-reactive protein (hs-CRP), white blood cell count (WBC), albumin] and baseline physical activity (PASE) and QoL (SF-36) were analysed. In the Leuven and Manchester cohort (n = 447), data were available on muscle mass (whole-body dual X-ray absorptiometry) and strength. In this subgroup, cross-sectional associations between baseline inflammatory markers and sarcopenia-defining parameters (handgrip strength, chair stand test, appendicular lean mass, and gait speed) and prevalent sarcopenia were examined. In a further subgroup (n = 277), associations with knee extensor strength were explored. Longitudinally, predictive value of baseline inflammation on functional decline, physical activity, QoL, and incident sarcopenia was examined. Subgroup analyses were performed in subgroups with chronic inflammation and stratified by age. Linear and logistic regressions were used, adjusted for age, body mass index, centre, and smoking.

RESULTS

At baseline, hs-CRP and WBC were negatively associated with PASE score (hs-CRP: β = -7.920, P < 0.001; and WBC: β = -4.552, P < 0.001) and the physical component score of SF-36 (hs-CRP: β = -1.025, P < 0.001; and WBC: β = -0.364, P < 0.001). Baseline WBC levels were negatively associated with gait speed (β = -0.013; P = 0.025), quadriceps isometric 90° (β = -5.983; P = 0.035) and isokinetic 60°/s peak torque/body weight (β = -5.532; P = 0.027). The prevalence of sarcopenia at baseline was 18.1% (n = 81). Of those without sarcopenia at baseline, 64 (18.6%) satisfied criteria for sarcopenia at follow-up. There were no significant associations between baseline inflammatory markers and either prevalent or incident sarcopenia, or change in level of sarcopenia-defining parameters between baseline and follow-up.

CONCLUSIONS

In middle-aged and older men, hs-CRP and WBC were negatively associated with QoL and PASE scores, while WBC was negatively associated with gait speed and knee strength. Associations with hs-CRP remained significant in all ages, whereas WBC levels were only associated with PASE, gait speed and knee strength in older adults (60-79 years). Baseline inflammatory markers (hs-CRP, WBC and albumin) did not predict functional decline, decline in physical activity, decreased QoL or incident sarcopenia.

Understanding of sarcopenia: from definition to therapeutic strategies

Sarcopenia refers to the gradual loss of skeletal muscle mass and function along with aging and is a social burden due to growing healthcare cost associated with a super-aging society. Therefore, researchers have established guidelines and tests to diagnose sarcopenia. Several studies have been conducted actively to reveal the cause of sarcopenia and find an economic therapy to improve the quality of life in elderly individuals. Sarcopenia is caused by multiple factors such as reduced regenerative capacity, imbalance in protein turnover, alteration of fat and fibrotic composition in muscle, increased reactive oxygen species, dysfunction of mitochondria and increased inflammation. Based on these mechanisms, nonpharmacological and pharmacological strategies have been developed to prevent and treat sarcopenia. Although several studies are currently in progress, no treatment is available yet. This review presents the definition of sarcopenia and summarizes recent understanding on the detailed mechanisms, diagnostic criteria, and strategies for prevention and treatment.

Impact of Sarcopenia on Two-Year Mortality in Patients with HCV-Associated Hepatocellular Carcinoma After Radiofrequency Ablation

Purpose

Radiofrequency ablation (RFA) appears effective for the treatment of hepatocellular carcinoma (HCC). Evaluation of prognostic factors is imperative for patient selection and improving treatment efficacy. This study aimed to assess sarcopenia as a predictor of the outcome of RFA in patients with HCC.

Methods

This prospective study included all patients with HCC on top of HCV-related cirrhosis who underwent RFA and followed up for a minimum of two years. CT scan was used to determine the skeletal muscle index at the psoas, erector spinae, quadratus lumborum, transversus abdominis, external and internal obliques, and rectus abdominis muscles. Cross-sectional areas were calculated to obtain a lumbar skeletal muscle index (L3-SMI).

Results

A total of 97 patients were enrolled in the study. The L3-SMI was 46.2±12.1 cm²/m². Older age was the only risk factor associated with sarcopenia (p = 0.001). The overall survival at two years for the whole group was 65.2%. Sarcopenia and MELD score were independent predictors of OS at two years with HR of 7.6 (95% CI: 3.1-18.7) and 2.2 (95% CI: 1.0-4.8), respectively. Recurrence-free survival was 84.1% at two years. Recurrence was not affected by all factors, including sarcopenia.

Conclusion

Sarcopenia is a surrogate predictor of overall survival at two years in HCC patients after RFA. Sarcopenia assessment might be an additional prognostic indicator with conventional biomarkers to optimize the selection criteria for receiving RFA for early-stage HCC.

Emerging Treatment Options for Sarcopenia in Chronic Liver Disease

Sarcopenia is characterized by a skeletal muscle disorder with progressive and generalized loss of muscle mass and function, and it increases the risk of adverse outcomes with considerable prevalence in patients with chronic liver disease. Sarcopenia in chronic liver disease underlies complicated and multifactorial mechanisms for pathogenesis, including alterations in protein turnover, hyperammonemia, energy disposal, hormonal changes, and chronic inflammation. The key contribution to sarcopenia in patients with chronic liver diseases can be the hyperammonemia-induced upregulation of myostatin, which causes muscle atrophy via the expression of atrophy-related genes. Several clinical studies on emerging treatment options for sarcopenia have been reported, but only a few have focused on patients with chronic liver diseases, with mostly nutritional and behavioral interventions being carried out. The inhibition of the myostatin-activin receptor signaling pathway and hormonal therapy might be the most promising therapeutic options in combination with an ammonia-lowering approach in sarcopenic patients with chronic liver diseases. This review focuses on current and emerging treatment options for sarcopenia in chronic liver diseases with underlying mechanisms to counteract this condition.

Sex-Specific Differences in the Effect of Free Testosterone on Sarcopenia Components in Older Adults

OBJECTIVE

The association of free testosterone (FT) with sarcopenia and its components is well known in men but incompletely understood in women. We examined the association of baseline FT with the prevalence and incidence of sarcopenia and its components in community-dwelling older adults.

DESIGN

Cross-sectional and longitudinal analysis from the prospective population-based Korean Frailty and Aging Cohort Study.

METHODS

A total of 1,879 community-dwelling older adults aged 70-84 years were enrolled for cross-sectional analysis and 1,583 subjects who participated in the 2-year follow-up survey were included for longitudinal analysis. Baseline FT levels was measured by radioimmunoassay. Skeletal muscle mass, handgrip strength, and physical performance tests were measured at baseline and after 2-year follow-up. Sarcopenia was defined by the diagnostic criteria of the Asian Working Group for Sarcopenia (AWGS).

RESULTS

Continuous FT levels was positively associated with the prevalence of sarcopenia in men (odds ratio [OR]=0.95; 95% confidence interval [CI]=0.89-1.00)] and women (OR=0.64, 95% CI=0.42-0.99) after adjusting for multiple confounders. In prospective analysis, low FT levels was associated with a decrease in handgrip strength in women (β=-0.61; p=0.010) and a reduction in Timed "Up and Go" (TUG) test (β=0.53; p=0.008) in men after 2 years. No significant correlations were found between FT levels and the incidence of sarcopenia.

CONCLUSIONS

Low levels of FT may be a significant determinant of decreases in muscle strength in women and declines in physical performance in men after 2 years. Low FT do not predict loss of muscle mass in both men and women.

Role of hormones in sarcopenia

Aging involves numerous changes in body composition that include a decrease in skeletal muscle mass. The gradual reduction in muscle mass is associated with a simultaneous decrease in muscle strength, which leads to reduced mobility, fragility and loss of independence. This process called sarcopenia is secondary to several factors such as sedentary lifestyle, inadequate nutrition, chronic inflammatory state and neurological alterations. However, the endocrine changes associated with aging seem to be of special importance in the development of sarcopenia. On one hand, advancing age is associated with a decreased secretion of the main hormones that stimulate skeletal muscle mass and function (growth hormone, insulin-like growth factor 1 (IGFI), testosterone and estradiol). On the other hand, the alteration of the IGF-I signaling along with decreased insulin sensitivity also have an important impact on myogenesis. Other hormones that decline with aging such as the adrenal-derived dehydroepiandrosterone, thyroid hormones and vitamin D seem to also be involved in sarcopenia. Adipokines released by adipose tissue show important changes during aging and can affect muscle physiology and metabolism. In addition, catabolic hormones such as cortisol and angiotensin II can accelerate aged-induced muscle atrophy, as they are involved in muscle wasting and their levels increase with age. The role played by all of these hormones and the possible use of some of them as therapeutic tools for treating sarcopenia will be discussed.

Sarcopenia: Molecular Pathways and Potential Targets for Intervention

Aging is associated with sarcopenia. The loss of strength results in decreased muscle mass and motor function. This process accelerates the progressive muscle deterioration observed in older adults, favoring the presence of debilitating pathologies. In addition, sarcopenia leads to a decrease in quality of life, significantly affecting self-sufficiency. Altogether, these results in an increase in economic resources from the National Health Systems devoted to mitigating this problem in the elderly, particularly in developed countries. Different etiological determinants are involved in the progression of the disease, including: neurological factors, endocrine alterations, as well as nutritional and lifestyle changes related to the adoption of more sedentary habits. Molecular and cellular mechanisms have not been clearly characterized, resulting in the absence of an effective treatment for sarcopenia. Nevertheless, physical activity seems to be the sole strategy to delay sarcopenia and its symptoms. The present review intends to bring together the data explaining how physical activity modulates at a molecular and cellular level all factors that predispose or favor the progression of this deteriorating pathology.

Pre-sarcopenia is the prognostic factor of overall survival in early-stage hepatoma patients undergoing radiofrequency ablation

Sarcopenia might have impact on the outcome of patients with hepatoma carcinoma (HCC). This study was to determine whether pre-sarcopenia is associated with the outcome of HCC patients undergoing radiofrequency ablation (RFA).Patients with newly diagnosed HCC undergoing RFA were enrolled. We excluded patients without pre-RFA abdominal computed tomography or with incomplete ablation. Psoas muscle area index was calculated at the mid-lumbar 3 level of computed tomography images with the manual trace method. Pre-sarcopenia was defined as psoas muscle area index less than 4.24 and 2.50 cm/m for males and females respectively. The demographics and clinical characteristics were recorded before RFA.All patients were followed regularly until death or end of 2018. A total of 136 patients, including - BCLC stage 0 (n = 44, 32.4%) and - stage A (n = 92, 67.6%), were enrolled (males/females: 78/58, age: 65.4 years) with a mean follow-up period of 3.84 years. There were 75 patients (55.1%) with HCC recurrence and 47 patients (34.6%) with mortality during follow-up. Twenty-two (16.2%) patients were diagnosed with pre-sarcopenia. Multivariate analysis showed pre-sarcopenia (HR: 2.110 (1.092-4.078); P = .026) was the only factor significantly associated with overall survival (OS); however, there were no factors associated with HCC recurrence.For patients without and with pre-sarcopenia, the 1-, 3-, and 5-year OS rates were 92.0%, 77.6%, 68.9%, and 81.8%, 54.5%, 44.1% respectively (P = .007). For early-stage HCC patients undergoing RFA, pre-sarcopenia is the prognostic factor of OS, but not of recurrence, with a worse 5-year OS rate of 44.1%.

The effect of Korean Red Ginseng on sarcopenia biomarkers in type 2 diabetes patients

BACKGROUND

The elderly population is growing rapidly worldwide and sarcopenia, which is considered as a new geriatric syndrome has become an important issue. In particular, diabetes is known to be an important risk factor for sarcopenia. In this study, we investigated the effects of Korean Red Ginseng (KRG) on biomarkers of sarcopenia in middle and old age diabetes patients.

PATIENTS AND METHODS

This study was a randomized, double-blind, placebo-controlled trial. Participants were randomly allocated to either the placebo or KRG group and took corresponding tablets for 24 weeks. The primary outcomes were changes in sarcopenia biomarkers at week 24. Secondary outcomes were changes in inflammatory and antioxidant markers and lean body mass at week 24.

RESULTS

Fifty-nine patients completed the study. Follistatin and sex hormone binding globulin (SHBG) were significantly improved in KRG group. In the subgroup analysis, female postmenopausal patients over the age of 55 showed a significant improvement in serum SHBG, follistatin, and growth differentiation factor 15 (GDF-15) and an attenuated reduction in Troponin T (TNT) after the administration of KRG.

CONCLUSION

Twenty-four week administration of KRG in diabetes patients resulted in a significant improvement in follistatin and SHBG levels, especially in old postmenopausal women. A further, larger population study with a longer follow-up period is warranted to verify and understand the effects of KRG on sarcopenia.

The mechanisms and treatments for sarcopenia: could exosomes be a perspective research strategy in the future?

The age-related loss of muscle mass and muscle function known as sarcopenia is a primary contributor to the problems faced by the old people. Sarcopenia has been a major public health problem with high prevalence in many countries. The related underlying molecular mechanisms of sarcopenia are not completely understood. This review is focused on the potential mechanisms and current research strategies for sarcopenia with the aim of facilitating the recognition and treatment of age-related sarcopenia. Previous studies suggested that protein synthesis and degradation, autophagy, impaired satellite cell activation, mitochondria dysfunction, and other factors associated with muscle weakness and muscle degeneration may be potential molecular pathophysiology of sarcopenia. Importantly, we also prospectively highlight that exosomes (small vesicles) as carriers can regulate muscle regeneration and protein synthesis according to recent researches. Dietary strategies and exercise represent the interventions that can also alleviate the progression of sarcopenia. At last, building on recent studies pointing to exosomes with the roles in increasing muscle regeneration, mediating the beneficial effects of exercise, and serving as messengers of intercellular communication and as carriers for research strategies of many diseases, we propose that exosomes could be a potential research direction or strategies of sarcopenia in the future.

Multiplex Analysis of Circulating Hormone Levels in Rat Models of Age-Related Diseases

This chapter describes the application of multiplex immunoassay of hormones which are known to be present at different levels during aging and may therefore be precipitous in age-related diseases. As an example, we have analyzed serum from 12-week-old rats using multiplexes for the hormones insulin, leptin, growth hormone, corticosterone, and testosterone, which have been implicated in sarcopenia. The same technique can be used in the investigation of other sarcopenia biomarkers as well as in other disease cases involving both clinical and preclinical biomarker studies.

Chronic vitamin D insufficiency impairs physical performance in C57BL/6J mice

Vitamin D insufficiency (serum 25-OH vitamin D < 30 ng/ml) affects 70-80% of the general population, yet the long-term impacts on physical performance and the progression of sarcopenia are poorly understood. We therefore followed 6-month-old male C57BL/6J mice (n=6) consuming either sufficient (STD, 1000 IU) or insufficient (LOW, 125 IU) vitamin D3/kg chow for 12 months (equivalent to 20-30 human years). LOW supplemented mice exhibited a rapid decline of serum 25-OH vitamin D levels by two weeks that remained between 11-15 ng/mL for all time points thereafter. After 12 months LOW mice displayed worse grip endurance (34.6 ± 14.1 versus 147.5 ± 50.6 seconds, p=0.001), uphill sprint speed (16.0 ± 1.0 versus 21.8 ± 2.4 meters/min, p=0.0007), and stride length (4.4 ± 0.3 versus 5.1 ± 0.3, p=0.002). LOW mice also showed less lean body mass after 8 months (57.5% ± 5.1% versus 64.5% ± 4.0%, p=0.023), but not after 12 months of supplementation, as well as greater protein expression of atrophy pathway gene atrogin‑1. Additionally, microRNA sequencing revealed differential expression of mIR‑26a in muscle tissue of LOW mice. These data suggest chronic vitamin D insufficiency may be an important factor contributing to functional decline and sarcopenia.

Vitamin D in Relation to Incident Sarcopenia and Changes in Muscle Parameters Among Older Adults: The KORA-Age Study

Effects of low serum 25OHD on age-related changes in muscle mass and function remain unclear. Our aims were to explore associations of baseline 25OHD levels with prevalent and incident sarcopenia and changes in muscle parameters, and to examine the role of parathyroid hormone (PTH) therein. Cross-sectional (n = 975) and prospective analyses (n = 702) of older adults aged 65-93 years participating in the KORA-Age study. Sarcopenia was defined using the 2010 European Working Group on Sarcopenia in Older People (EWGSOP) criteria as low muscle mass combined with low grip strength or low physical performance. Associations with baseline 25OHD were examined in multiple regression analyses. Low vitamin D status was linked to increased odds of prevalent sarcopenia. Over three years, low baseline 25OHD < 25 vs. ≥ 50 nmol/L were associated with greater loss of muscle mass and increased time for the Timed Up and Go test. The risk for developing incident sarcopenia was not significantly elevated in individuals with low baseline 25OHD but when including death as combined outcome alongside incident sarcopenia, there was a strong positive association in multivariable analysis [OR (95% CI) 3.19 (1.54-6.57) for 25OHD < 25 vs. ≥ 50 nmol/L]. There was no evidence for a PTH-mediating effect. Low baseline 25OHD levels were associated with unfavorable changes in muscle mass and physical performance, but not with incident sarcopenia. Future randomized trials are needed to assess causality and to address the issue of competing risks such as mortality in older cohorts.

Change in grip strength in trans people and its association with lean body mass and bone density

OBJECTIVE

Gender-affirming hormonal treatment (HT) in trans people changes physical appearance. Muscle mass and strength are important aspects of physical appearance, but few data exist on the effect of HT on grip strength and muscle mass. This study aimed to investigate the change in grip strength in trans people during the first year of HT and to study the possible determinants of this change and the associations between changes in grip strength, lean body mass and bone mineral density (BMD).

DESIGN AND METHODS

A multicenter, prospective study was performed, including 249 transwomen and 278 transmen. Grip strength, lean body mass and BMD were measured at baseline and after 1 year.

RESULTS

After 1 year of HT, grip strength decreased with -1.8 kg (95% CI -2.6; -1.0) in transwomen and increased with +6.1 kg (95% CI +5.5; +6.7) in transmen. No differences in grip strength change was found between age groups, BMI groups, hormonal administration routes or hormone concentrations. In transmen, increase in grip strength was associated with increase in lean body mass (per kg increase in grip strength: +0.010 kg, 95% CI +0.003; +0.017), while this was not found in transwomen (per kg increase in grip strength: +0.004 kg, 95% CI -0.000; +0.009). Change in grip strength was not associated with change in BMD in transwomen and transmen.

CONCLUSIONS

After 1 year of HT, grip strength decreased in transwomen, and increased in transmen. In transmen only, change in grip strength was associated with change in lean body mass.

Sarcopenia

Sarcopenia is a progressive and generalised skeletal muscle disorder involving the accelerated loss of muscle mass and function that is associated with increased adverse outcomes including falls, functional decline, frailty, and mortality. It occurs commonly as an age-related process in older people, influenced not only by contemporaneous risk factors, but also by genetic and lifestyle factors operating across the life course. It can also occur in mid-life in association with a range of conditions. Sarcopenia has become the focus of intense research aiming to translate current knowledge about its pathophysiology into improved diagnosis and treatment, with particular interest in the development of biomarkers, nutritional interventions, and drugs to augment the beneficial effects of resistance exercise. Designing effective preventive strategies that people can apply during their lifetime is of primary concern. Diagnosis, treatment, and prevention of sarcopenia is likely to become part of routine clinical practice.

Preventive Effects of Low Parathyroid Hormone Levels on Hip Fracture in Patients with Vitamin D Deficiency

Background

The objective of the current study is to determine the role of serum parathyroid hormone (PTH) on hip fracture development by retrospectively analyzing the relationship between vitamin D and PTH levels and hip fracture prevalence.

Methods

Among 288 patients over 50 years of age, 113 patients with hip fracture and 111 controls without fracture were analyzed after excluding patients with conditions affecting bone metabolism. Bone mineral density and serum biochemical markers were measured, while demographic data were obtained. Patients were divided into 4 groups according to serum 25-hydroxy-vitamin D (25-[OH]D) and PTH levels: LowD+LowP (low 25[OH]D and PTH); LowD+HighP, (low 25[OH]D and high PTH); HighD+LowP (high 25[OH]D and low PTH); and HighD+HighP, patients with (high 25[OH]D and PTH). Measured values and percentages of patients with hip fracture in each group were then determined and compared.

Results

The number of patients included in the LowD+LowP, LowD+HighP, HighD+LowP, and HighD+HighP groups was 116, 17, 87, and 4, while the percentages of patients with hip fracture in the same groups were 60.3%, 88.2%, 27.6%, and 100%, respectively. The percentage of hip fracture was significantly lower in the LowD+LowP than the LowD+HighP group (P=0.049).

Conclusions

Patients with low serum 25(OH)D and PTH levels showed lower hip fracture prevalence, indicating the potential protective role of low PTH levels on bone health in patients with vitamin D deficiency. Therefore, clinicians should pay more attention to the possibility of fractures in patients with vitamin D deficiency who present with high PTH levels.

Myricanol rescues dexamethasone-induced muscle dysfunction via a sirtuin 1-dependent mechanism

BACKGROUND

Muscle atrophy and weakness are adverse effects of high dose or the sustained usage of glucocorticoids. Loss of mitochondria and degradation of protein are highly correlated with muscle dysfunction. The deacetylase sirtuin 1 (SIRT1) plays a vital role in muscle remodelling. The current study was designed to identify myricanol as a SIRT1 activator, which could protect skeletal muscle against dexamethasone-induced wasting.

METHODS

The dexamethasone-induced atrophy in C2C12 myotubes was evaluated by expression of myosin heavy chain, muscle atrophy F-box (atrogin-1), and muscle ring finger 1 (MuRF1), using western blots. The mitochondrial content and oxygen consumption were assessed by MitoTracker staining and extracellular flux analysis, respectively. Muscle dysfunction was established in male C57BL/6 mice (8-10 weeks old, n = 6) treated with a relatively high dose of dexamethasone (25 mg/kg body weight, i.p., 10 days). Body weight, grip strength, forced swimming capacity, muscle weight, and muscle histology were assessed. The expression of proteolysis-related, autophagy-related, apoptosis-related, and mitochondria-related proteins was analysed by western blots or immunoprecipitation.

RESULTS

Myricanol (10 μM) was found to rescue dexamethasone-induced muscle atrophy and dysfunction in C2C12 myotubes, indicated by increased expression of myosin heavy chain (0.33 ± 0.14 vs. 0.89 ± 0.21, *P < 0.05), decreased expression of atrogin-1 (2.31 ± 0.67 vs. 1.53 ± 0.25, *P < 0.05) and MuRF1 (1.55 ± 0.08 vs. 0.99 ± 0.12, **P < 0.01), and elevated ATP production (3.83 ± 0.46 vs. 5.84 ± 0.79 nM/mg protein, **P < 0.01), mitochondrial content (68.12 ± 10.07% vs. 116.38 ± 5.12%, *P < 0.05), and mitochondrial oxygen consumption (166.59 ± 22.89 vs. 223.77 ± 22.59 pmol/min, **P < 0.01). Myricanol directly binds and activates SIRT1, with binding energy of -5.87 kcal/mol. Through activating SIRT1 deacetylation, myricanol inhibits forkhead box O 3a transcriptional activity to reduce protein degradation, induces autophagy to enhance degraded protein clearance, and increases peroxisome proliferator-activated receptor γ coactivator-1α activity to promote mitochondrial biogenesis. In dexamethasone-induced muscle wasting C57BL/6 mice, 5 mg/kg myricanol treatment reduces the loss of muscle mass; the percentages of quadriceps and gastrocnemius muscle in myricanol-treated mice are 1.36 ± 0.02% and 0.87 ± 0.08%, respectively (cf. 1.18 ± 0.06% and 0.78 ± 0.05% in dexamethasone-treated mice, respectively). Myricanol also rescues dexamethasone-induced muscle weakness, indicated by improved grip strength (70.90 ± 4.59 vs. 120.58 ± 7.93 g, **P < 0.01) and prolonged swimming exhaustive time (48.80 ± 11.43 vs. 83.75 ± 15.19 s, **P < 0.01). Myricanol prevents dexamethasone-induced muscle atrophy and weakness by activating SIRT1, to reduce muscle protein degradation, enhance autophagy, and promote mitochondrial biogenesis and function in mice.

CONCLUSIONS

Myricanol ameliorates dexamethasone-induced skeletal muscle wasting by activating SIRT1, which might be developed as a therapeutic agent for treatment of muscle atrophy and weakness.

Age-related bone loss and sarcopenia in men

Bone and muscle are required for mobility but they also have endocrine and metabolic functions. In ageing as well as in many chronic diseases, bone loss and muscle atrophy occur simultaneously, leading to concomitant osteoporosis and sarcopenia. This occurs in both genders but compared with postmenopausal women, men appear to be better protected against age-related bone and muscle decay. Sex steroids (both androgens like testosterone and oestrogens like estradiol) are mainly responsible for musculoskeletal sexual dimorphism. They stimulate peak bone and muscle mass accretion during puberty and midlife, and prevent subsequent loss in ageing men but not post-menopausal women. Still, recent studies have highlighted the importance of intrinsic ageing mechanisms such as cellular senescence and oxidative stress in both genders. Sarcopenia may predispose to dysmobility, frailty, falls and fractures, but whether so-called osteosarcopenia qualifies as a distinct entity remains debated. Although randomized clinical trials in male osteoporosis are smaller and therefore underpowered for some outcomes like hip fractures, the available evidence suggests that the clinical diagnostic and therapeutic approach to male osteoporosis is largely similar to that in postmenopausal women. There is a clear unmet medical need for effective and safe anabolic drugs to rebuild the ageing skeleton, muscle, and preferably both tissues simultaneously. The Wnt/sclerostin and myostatin/activin receptor signalling pathways appear particularly promising in this regard. In this narrative review, we aim to provide an overview of our current understanding of the pathophysiology and treatment of male osteoporosis and sarcopenia, and interactions between these two diseases.

Skeletal muscle wasting in chronic heart failure

Patients suffering from chronic heart failure (CHF) show an increased prevalence (~20% in elderly CHF patients) of loss of muscle mass and muscle function (i.e. sarcopenia) compared with healthy elderly people. Sarcopenia, which can also occur in obese patients, is considered a strong predictor of frailty, disability, and mortality in older persons and is present in 5–13% of elderly persons aged 60–70 years and up to 50% of all octogenarians. In a CHF study, sarcopenia was associated with lower strength, reduced peak oxygen consumption (peak VO₂, 1173 ± 433 vs. 1622 ± 456 mL/min), and lower exercise time (7.7 ± 3.8 vs. 10.22 ± 3.0 min, both P < 0.001). Unfortunately, there are only very limited therapy options. Currently, the main intervention remains resistance exercise. Specialized nutritional support may aid the effects of resistance training. Testosterone has significant positive effects on muscle mass and function, and low endogenous testosterone has been described as an independent risk factor in CHF in a study with 618 men (hazard ratio 0.929, P = 0.042). However, the use of testosterone is controversial because of possible side effects. Selective androgen receptor modulators have been developed to overcome these side effects but are not yet available on the market. Further investigational drugs include growth hormone, insulin‐like growth factor 1, and several compounds that target the myostatin pathway. The continuing development of new treatment strategies and compounds for sarcopenia, muscle wasting regardless of CHF, and cardiac cachexia makes this a stimulating research area.

Dysregulated homeostatic pathways in sarcopenia among frail older adults

Sarcopenia, a core feature of the physical frailty syndrome, is characterized by multisystem physiological dysregulation. No study has explored qualitatively the hierarchical network of relationships among different dysregulated pathways involved in the pathogenesis of sarcopenia. We used 40 blood biomarkers belonging to community‐dwelling prefrail and frail older persons to derive measures of multiple physiological pathways, and structural equation modeling to generate path network models of the multisystem physiological dysregulations associated with muscle mass and function (MMF). Insulin–leptin signaling and energy regulation, anabolic sex steroid regulation (testosterone, leptin), and tissue oxygenation (hemoglobin, red cell count) appear to be primary mediating factors exerting direct influences on MMF. There was additionally secondary mediatory involvement of myocyte‐ and adipocyte‐derived cytokines, hypothalamic pituitary adrenal (HPA) stress hormones (cortisol, DHEAS), glomerular function, and immune cell regulatory and inflammatory cytokines and glycoproteins. We conclude that within a hierarchical network of multisystem physiological dysregulations in sarcopenia, dysregulated anabolic and catabolic pathways via sex steroids and insulin–leptin dual signaling and tissue hypoxemia are primary physiological dysregulations responsible for sarcopenia and frailty.

The relationship between serum IGF-1, handgrip strength, physical performance and falls in elderly men and women

OBJECTIVE

Human aging is accompanied by a decrease in growth hormone secretion and serum insulin-like growth factor (IGF)-1 levels. Also, loss of muscle mass and strength and impairment of physical performance, ending in a state of frailty, are seen in elderly. We aimed to investigate whether handgrip strength, physical performance and recurrent falls are related to serum IGF-1 levels in community-dwelling elderly.

DESIGN

Observational cohort study (cross-sectional and prospective).

METHODS

We studied the association between IGF-1 and handgrip strength, physical performance and falls in participants of the Longitudinal Aging Study Amsterdam. A total of 1292 participants were included (633 men, 659 women). Serum IGF-1 levels were divided into quartiles (IGF-1-Q1 to IGF-1-Q4). Data on falls were collected prospectively for a period of 3 years. All analyses were stratified for age and physical activity and adjusted for relevant confounders.

RESULTS

Men with a low physical activity score in IGF-1-Q1 and IGF-1-Q2 of the younger age group had a lower handgrip strength compared to IGF-1-Q4. In younger more active males in IGF-1-Q2 physical performance was worse. Recurrent fallers were less prevalent in older, low active males with low IGF-1 levels. In females, recurrent fallers were more prevalent in older, more active females in IGF-1-Q2. IGF-1 quartile may predict changes in handgrip strength and physical performance in men and women.

CONCLUSIONS

Our results indicate that lower IGF-1 levels are associated with lower handgrip strength and worse physical performance, but less recurrent fallers especially in men. Associations were often more robust in IGF-1-Q2. Future studies on this topic are desirable.

Muscle wasting and sarcopenia in heart failure and beyond: update 2017

Sarcopenia (loss of muscle mass and muscle function) is a strong predictor of frailty, disability and mortality in older persons and may also occur in obese subjects. The prevalence of sarcopenia is increased in patients suffering from chronic heart failure. However, there are currently few therapy options. The main intervention is resistance exercise, either alone or in combination with nutritional support, which seems to enhance the beneficial effects of training. Also, testosterone has been shown to increased muscle power and function; however, a possible limitation is the side effects of testosterone. Other investigational drugs include selective androgen receptor modulators, growth hormone, IGF‐1, compounds targeting myostatin signaling, which have their own set of side effects. There are abundant prospective targets for improving muscle function in the elderly with or without chronic heart failure, and the continuing development of new treatment strategies and compounds for sarcopenia and cardiac cachexia makes this field an exciting one.

Reproductive Hormone Levels Predict Changes in Frailty Status in Community-Dwelling Older Men: European Male Ageing Study Prospective Data

CONTEXT

Clinical sequelae of androgen deficiency share common features with frailty. Evidence supporting the role of androgens in the development of frailty is limited and conflicting.

OBJECTIVE

To determine associations between male reproductive hormones and prospective changes in frailty status.

DESIGN/SETTING

A 4.3-year prospective cohort study of community-dwelling men participating in the European Male Ageing Study.

PARTICIPANTS

A total of 3369 men aged 40 to 79 from eight European centers.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Frailty status was determined using frailty index (FI; n = 2278) and frailty phenotype (FP; n = 1980).

RESULTS

After adjusting for baseline frailty, age, center, and smoking, the risk of worsening FI decreased with higher testosterone (T), free T, and dihydrotestosterone (DHT) [percentage change (95% confidence interval) in FI associated with 1 standard deviation higher hormone level: -3.0 (-5.9, -1.0) for total T; -3.9 (-6.8, -2.0) for free T; and -3.9 (-6.8, -2.0) for DHT]. After further adjustment for body mass index, only free T remained a significant predictor of FI change. In fully adjusted models, higher luteinizing hormone and follicle-stimulating hormone were positively related to worsening FI only in men <60 years, and higher estradiol predicted lower likelihood of improving FP [odds ratio: 0.68 (0.52, 0.88)].

CONCLUSIONS

These prospective data support the hypothesis that higher androgen levels may protect elderly men from worsening frailty. However, the causal nature of these relationships requires further investigation. Whereas raised gonadotropins in men <60 years might be an early marker of frailty, the role of estradiol in frailty needs further clarification.

Long-Term Administration of Queen Bee Acid (QBA) to Rodents Reduces Anxiety-Like Behavior, Promotes Neuronal Health and Improves Body Composition

Background: Queen bee acid (QBA; 10-hydroxy-2-decenoic acid) is the predominant fatty acid in royal jelly (RJ) and has activity at estrogen receptors, which affect brain function and body composition. However, few, long-term studies have assessed QBA effects in brain health and body composition. Methods: Primary hippocampal neurons were treated with QBA (0–30 µM) and challenged with glutamate or hypoxia. QBA was fed to aged, male Sprague-Dawley rats (12–24 mg/kg/day) and to adult male and female Balb/C mice (30–60 mg/kg/day) for ≥3.5 months. Rats were evaluated in a behavioral test battery of brain function. Mice were measured for fat and muscle composition, as well as bone density. Results: QBA increased neuron growth and protected against glutamate challenge and hypoxia challenge. Rats receiving QBA had reduced anxiety-like behavior, increased body weight, and better maintenance of body weight with age. Mice receiving QBA exhibited increased body weight, muscle mass, and adiposity in males, and increased bone density, but decreased adiposity, in females. Conclusions: QBA is an active component of RJ that promotes the growth and protection of neurons, reduces anxiety-like phenotypes, and benefits bone, muscle and adipose tissues in a sex-dependent manner, which further implicates estrogen receptors in the effects of QBA.

Casting the net broader to confirm our imaginations: the long road to treating wasting disorders

Wasting embraces muscle and tissue wasting in sarcopenia and cachexia. This article describes recent advances in the field published in the Journal of Cachexia, Sarcopenia and Muscle concerning diagnostic tools, biomarker development, pathophysiology, and treatment. Studies discussed herein embrace those on sarcopenia and cachexia in heart failure, chronic obstructive pulmonary disease, and cancer including also animal models.

An analysis of the types of recently published research in the field of cachexia

Introduction Cachexia is a common complication of many and varied chronic disease processes, yet it has received very little attention as an area of clinical research effort until recently. We sought to survey the contemporary literature on published research into cachexia to define where it is being published and the proportion of output classified into the main types of research output. Methods I searched the PubMed listings under the topic research term "cachexia" and related terms for articles published in the calendar years of 2015 and 2016, regardless of language. Searches were conducted and relevant papers extracted by two observers, and disagreements were resolved by consensus. Results There were 954 publications, 370 of which were review articles or commentaries, 254 clinical observations or non-randomised trials, 246 original basic science reports and only 26 were randomised controlled trials. These articles were published in 478 separate journals but with 36% of them being published in a core set of 23 journals. The H-index of these papers was 25 and there were 147 papers with 10 or more citations. Of the top 100 cited papers, 25% were published in five journals. Of the top cited papers, 48% were review articles, 18% were original basic science, and 7% were randomised clinical trials. Discussion This analysis shows a steady but modest increase in publications concerning cachexia with a strong pipeline of basic science research but still a relative lack of randomised clinical trials, with none exceeding 1000 patients. Research in cachexia is still in its infancy, but the solid basic science effort offers hope that translation into randomised controlled clinical trials may eventually lead to effective therapies for this troubling and complex clinical disease process.