Association between Sarcopenia and Insulin-Like Growth Factor-1, Myostatin, and Insulin Resistance in Elderly Patients Undergoing Hemodialysis

Predictive model for sarcopenia in chronic kidney disease: a nomogram and machine learning approach using CHARLS data

Background

Sarcopenia frequently occurs as a complication among individuals with chronic kidney disease (CKD), contributing to poorer clinical outcomes. This research aimed to create and assess a predictive model for the risk of sarcopenia in CKD patients, utilizing data obtained from the China Health and Retirement Longitudinal Study (CHARLS).

Methods

Sarcopenia was diagnosed based on the Asian Working Group for Sarcopenia (AWGS 2019) criteria, including low muscle strength, reduced physical performance, and low muscle mass. The 2015 CHARLS data were split randomly into a training set (70%) and a testing set (30%). Forty-nine variables encompassing socio-demographic, behavioral, health status, and biochemical factors were analyzed. LASSO regression identified the most relevant predictors, and a logistic regression model was used to explore factors associated with sarcopenia. A nomogram was developed for risk prediction. Model accuracy was evaluated using calibration curves, while predictive performance was assessed through receiver operating characteristic (ROC) and decision curve analysis (DCA). Four machine learning algorithms were utilized, with the optimal model undergoing hyperparameter optimization to evaluate the significance of predictive factors.

Results

A total of 1,092 CKD patients were included, with 231 (21.2%) diagnosed with sarcopenia. Multivariate logistic regression revealed that age, waist circumference, LDL-C, HDL-C, triglycerides, and diastolic blood pressure are significant predictors. These factors were used to construct the nomogram. The predictive model achieved an AUC of 0.886 (95% CI: 0.858-0.912) in the training set and 0.859 (95% CI: 0.811-0.908) in the validation set. Calibration curves showed good agreement between predicted and actual outcomes. ROC and DCA analyses confirmed the model's strong predictive performance. The Gradient Boosting Machine (GBM) outperformed other machine learning models. Applying Bayesian optimization to the GBM achieved an AUC of 0.933 (95% CI: 0.913-0.953) on the training set and 0.932 (95% CI: 0.905-0.960) on the validation set. SHAP values identified age and waist circumference as the most influential factors.

Conclusion

The nomogram provides a reliable tool for predicting sarcopenia in CKD patients. The GBM model exhibits strong predictive accuracy, positioning it as a valuable tool for clinical risk assessment and management of sarcopenia in this population.

A framework of biomarkers for skeletal muscle aging: a consensus statement by the Aging Biomarker Consortium

The skeletal muscle is an important organ for movement and metabolism in human body, and its physiological aging underlies the occurrence of muscle atrophy and sarcopenia. China has the largest aging population in the world and is facing a grand challenge with how to prevent and treat skeletal muscle aging-related diseases. To address this difficult problem, the Aging Biomarker Consortium (ABC) of China has reached an expert consensus on biomarkers of skeletal muscle aging by synthesizing literatures and insights from scientists and clinicians. This consensus attempts to provide a comprehensive assessment of biomarkers associated with skeletal muscle aging, and proposes a systematic framework to classify them into three dimensions: functional, structural, and humoral. Within each dimension, the experts recommend clinically relevant biomarkers for skeletal muscle aging. This consensus aims to lay the foundation for future research on skeletal muscle aging, facilitating precise prediction, diagnosis, and treatment of skeletal muscle aging and sarcopenia. It is anticipated to make significant contributions to healthy aging of skeletal muscle in the elderly population in China and around the world as well.

Fasting Glycemia, Glycosylated Hemoglobin and Malnutrition Inflammation Are Associated With Sarcopenia in Older People With Chronic Kidney Disease Undergoing Hemodialysis Treatment: A Cross-Sectional Study

BACKGROUND

Contradictory data are available on the possible association between sarcopenia and other clinical disorders in patients with chronic kidney disease (CKD) undergoing hemodialysis.

OBJECTIVE

To determine the association between sarcopenia and markers associated with systemic inflammation, fasting glycemia, and quality of life in older people with CKD undergoing hemodialysis.

METHODS

This was an analytical cross-sectional study. People over 60 years with stage 5 CKD undergoing hemodialysis were invited to participate. Sarcopenia was assessed using the criteria of the European Working Group on Sarcopenia in Older People. Clinical variables such as body mass index, comorbidities, malnutrition inflammation, quality of life, fasting glycemia, glycosylated hemoglobin, hematocrit, uremia, creatinine, sodium, calcium, potassium, albumin, ferritin, C reactive protein were measured.

RESULTS

Twenty-three patients with CKD were included. The prevalence of sarcopenia was 56.5%. Sarcopenic participants showed higher fasting glycemia, glycosylated hemoglobin, and malnutrition inflammation, as well as expected lower physical performance compared to nonsarcopenic participants. Correlations that ranged from moderate to strong were observed between sarcopenia and clinical characteristics such as fasting glycemia (r=0.48; P<0.05), glycosylated hemoglobin (r=0.44; P<0.05), malnutrition inflammation (r=0.46; P<0.05), skeletal muscle mass (r=-0.70; P<0.01), and balance capacity (r=-0.66; P<0.01). Regression analyses showed that fasting glycemia increased the risk of sarcopenia by 1.82 times (OR=1.82; P=0.04).

CONCLUSIONS

In a sample of older people with CKD who underwent hemodialysis, sarcopenia was correlated with fasting glycemia, glycosylated hemoglobin, and malnutrition inflammation. However, only fasting glycemia was found to be a significant predictor of sarcopenia. More studies are needed to determine the influence of glycemic control on sarcopenia in older people with CKD.

The triglyceride glucose related index is an indicator of Sarcopenia

The triglyceride glucose (TyG) related index, a metric used to evaluate assessing insulin resistance (IR), has received limited attention in its association with sarcopenia. Our study aims to explore the predictive potential of the TyG index for sarcopenia. This study utilized data from the China Health and Retirement Longitudinal Study, a nationally representative, community-based cohort study, including a sample size of 10,537 participants aged 45 years and older. Associations between TyG related index and sacopenia was explored using multivariate logistic regression. Analysis of the predictive value of TyG related index for sarcopenia using receiver-operating characteristic curve (ROC). We evaluated the correlation between the TyG related index and the risk of sarcopenia using Cox proportional hazards models. Additionally, we utilized restricted cubic spline (RCS) regression analyses to explore the connections between the TyG-related index and sarcopenia. Logistic regression analysis showed an association between TyG (OR 0.961[0.955,0.968], P < 0.001), TyG-body mass index (TyG-BMI) (OR 0.872[0.867,0.878], P < 0.001), TyG- waist circumference (TyG-WC) (OR 0.896[0.890,0.902], P < 0.001) and sarcopenia. The results of the ROC analysis indicated that the area under the curve values for TyG, TyG-BMI, and TyG-WC were 0.659, 0.903, and 0.819, respectively. Compared to those without sarcopenia, patients with sarcopenia had a 37.7% (HR 0.623[0.502,0.774], P < 0.001), 4.8% (HR 0.952[0.947,0.958], P < 0.001), and 0.4% (HR 0.996[0.995,0.996], P < 0.001) lower risk with increasing TyG, TyG-BMI, and TyG-WC, respectively. RCS results show nonlinear relationship between TyG-BMI (P < 0.001) and TyG-WC (P < 0.001) and risk of sarcopenia. We observed a correlation between the TyG-related index and sarcopenia, with the TyG-BMI index demonstrating strong predictive capability for sarcopenia.

Assessing the causal relationship between frailty and sex hormone-binding globulin or insulin-like growth factor-1 levels: A sex-stratified bidirectional Mendelian Randomization study

BACKGROUND

The association between frailty and sex hormone-binding globulin (SHBG) or insulin-like growth factor-1(IGF-1) levels demonstrates sex differences with inconsistent conclusions. This study aims to explore the causal relationship between frailty and SHBG or IGF-1 levels through bidirectional Mendelian randomization (MR).

METHODS

We conducted two-sample bidirectional sex-stratified MR analyses using summary-level data from genome-wide association studies (GWASs) to examine the causal relationship between frailty and IGF-1 or SHBG levels, as measured by frailty index (FI) and frailty phenotype (FP). We use the random-effects inverse-variance weighted (IVW), weighted median, MR-Egger, MR-Egger intercept, and leave-one-out approaches.

RESULT

The relationship between frailty and SHBG or IGF-1 levels is inversely related, with a significant decrease in SHBG levels in females. Specifically, SHBG levels significantly decrease with FI (β = -5.49; 95 % CI: -9.67 to -1.32; FDR = 0.02) and more pronounced with FP (β = -10.14; 95 % CI: -16.16 to -4.13; FDR = 0.01), as determined by the IVW approach. However, reverse analysis shows no significant effect of IGF-1 or SHBG levels on either FI or FP (p > 0.05).

CONCLUSION

Our study indicates a negative correlation between frailty and the levels of SHBG and IGF-1. It is suggested that further research is required to establish cut-off values for SHBG and IGF-1 levels in the frailty population. This is particularly important for females at higher risk, such as those undergoing menopause, to enable comprehensive assessment and early prevention efforts. While the findings imply that reduced IGF-1 and SHBG levels may not directly contribute to frailty, it is important not to overlook the underlying mechanisms through which they may indirectly influence frailty.

New Insight in Using of Mesenchyme Stem Cell Conditioning Medium for the Impaired Muscle related Biomarkers: In vivo Study with Rat Model

AIMS AND OBJECTIVES

This study aimed to investigate the effects of Umbilical Cord Mesencymal Stem Cell Conditioning Medium (UC MSC-CM) administration on body weight recovery and the level of four molecular biomarkers, namely Superoxide Dismutase (SOD), vascular Endothelial Growth Factor (VEGF), C-Reactive Protein (CRP), and myostatin.

MATERIALS AND METHODS

Secretome was injected intramuscularly twice at 1.5 mL (day 7 and 14) into the right thigh of high-dose, short-term galactose-induced aging rats. The data of day 7 (before) and day 21 (after the administration) were evaluated. The body weights and the four biomarkers were measured before (day 7) and after intervention (day 21).

RESULTS

This study showed that the UC MSC-CM intramuscular administrations did not influence body weight regeneration. However, it could increase SOD and VEGF levels and decrease CRP and myostatin levels.

CONCLUSION

Treatment with UC MSC-CM is a promising and potential agent in treating sarcopenia.

Association between Triglyceride-glucose index and sarcopenia in China: A nationally representative cohort study

BACKGROUND

The relationship between sarcopenia and insulin resistance (IR) has seldom been reported. Triglyceride-glucose (TyG) index, a new IR indicator, has gained traction as a prognostic tool for many diseases. We aimed to investigate whether the level of TyG index was related to the incidence of sarcopenia.

METHOD

A total of 1819 participants above 60 without sarcopenia at baseline were included from the China Health and Retirement Longitudinal Study (CHARLS). Cox models were applied to evaluate the association between TyG and incident sarcopenia. Mediation analyses were performed to evaluate the contribution of the level of BMI to observed associations.

RESULTS

During a median follow-up of 4.0 years, 217 (11.9 %) participants developed sarcopenia. The multivariable-adjusted hazard ratios of total sarcopenia in higher quartiles of TyG index versus the lowest quartiles were 0.59, 0.61, and 0.46, respectively. There were significant trends toward a decreasing risk of sarcopenia across the quartiles of TyG index before adjusting for BMI, but no significant association was observed after accounting for BMI. The area under the ROC curve was 0.6281 (0.597-0.660). In subgroup analysis, there was an inverse significant association between TyG index and sarcopenia among male participants. In mediation analyses, BMI explained 88.7 % of the association of TyG index and sarcopenia.

CONCLUSIONS

Our findings indicated that TyG index was negatively associated with incident sarcopenia in older Chinese without considering BMI adjustment. The association was not more significant after adjusting for BMI. BMI mediated the relationship between sarcopenia and TyG index among older Chinese population. Future study should validate our findings in a larger population.

Prevalence of sarcopenia in patients with chronic kidney disease: a global systematic review and meta-analysis

Sarcopenia is a risk factor for adverse clinical outcomes in chronic kidney disease (CKD) patients, including mortality. Diagnosis depends on adopted consensus definition and cutoff values; thus, prevalence rates are generally heterogeneous. We conducted a systematic review and meta-analysis to investigate the global prevalence of sarcopenia and its traits across the wide spectrum of CKD. A systematic search was conducted using databases, including MEDLINE and EMBASE, for observational studies reporting the prevalence of sarcopenia. We considered sarcopenia according to the consensus definition of the European Working Group on Sarcopenia in Older People (EWGSOP), the Asian Working Group for Sarcopenia, the Foundation for the National Institutes of Health Sarcopenia Project, and the International Working Group on Sarcopenia (IWGS). Subgroup analyses by CKD stages, consensus, and gender were performed. Pooled prevalence was obtained from random-effect models. A total of 140 studies (42 041 patients) across 25 countries were included in this systematic review and meta-analyses. Global prevalence of sarcopenia was 24.5% [95% confidence interval (CI): 20.9-28.3) and did not differ among stages (P = 0.33). Prevalence varied according to the consensus definition from 11% to 30%, with no significant difference (P = 0.42). Prevalence of severe sarcopenia was 21.0% (95% CI: 11.7-32.0), with higher rates for patients on dialysis (26.2%, 95% CI: 16.6-37.1) compared to non-dialysis (3.0%, 95% CI: 0-11.1; P < 0.01). Sarcopenic obesity was observed in 10.8% (95% CI: 3.5-21.2). Regarding sarcopenia traits, low muscle strength was found in 43.4% (95%CI: 35.0-51.9), low muscle mass in 29.1% (95% CI: 23.9-34.5), and low physical performance in 38.6 (95% CI: 30.9-46.6) for overall CKD. Prevalence was only higher in patients on dialysis (50.0%, 95% CI: 41.7-57.4) compared to non-dialysis (19.6%, 95% CI: 12.8-27.3; P < 0.01) for low muscle strength. We found a high global prevalence of sarcopenia in the wide spectrum of CKD. Low muscle strength, the primary sarcopenia trait, was found in almost half of the overall population with CKD. Patients on dialysis were more prevalent to low muscle strength and severe sarcopenia. Nephrology professionals should be aware of regularly assessing sarcopenia and its traits in patients with CKD, especially those on dialysis.

Diabetes Mellitus Should Be Considered While Analysing Sarcopenia-Related Biomarkers

Sarcopenia is a chronic, progressive skeletal muscle disease characterised by low muscle strength and quantity or quality, leading to low physical performance. Patients with type 2 diabetes mellitus (T2DM) are more at risk of sarcopenia than euglycemic individuals. Because of several shared pathways between the two diseases, sarcopenia is also a risk factor for developing T2DM in older patients. Various biomarkers are under investigation as potentially valuable for sarcopenia diagnosis and treatment monitoring. Biomarkers related to sarcopenia can be divided into markers evaluating musculoskeletal status (biomarkers specific to muscle mass, markers of the neuromuscular junction, or myokines) and markers assuming causal factors (adipokines, hormones, and inflammatory markers). This paper reviews the current knowledge about how diabetes and T2DM complications affect potential sarcopenia biomarker concentrations. This review includes markers recently proposed by the expert group of the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) as those that may currently be useful in phase II and III clinical trials of sarcopenia: myostatin (MSTN); follistatin (FST); irisin; brain-derived neurotrophic factor (BDNF); procollagen type III N-terminal peptide (PIIINP; P3NP); sarcopenia index (serum creatinine to serum cystatin C ratio); adiponectin; leptin; insulin-like growth factor-1 (IGF-1); dehydroepiandrosterone sulphate (DHEAS); C-reactive protein (CRP); interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). A better understanding of factors influencing these biomarkers' levels, including diabetes and diabetic complications, may lead to designing future studies and implementing results in clinical practice.

Relation between myostatin levels and malnutrition and muscle wasting in hemodialysis patients

BACKGROUND AND AIM

Malnutrition is one of the most troublesome comorbidities among hemodialysis patients (HD). Myostatin (MSTN) belongs to the transforming growth factor-β superfamily. In HD patients, MSTN effects are not limited to skeletal muscle growth. The present study aimed to assess MSTN levels in HD patients and its relation to various clinical and biochemical parameters.

PATIENTS AND METHODS

The present case control study included 60 patients on HD for at least three years. In addition, there were age and sex-matched healthy subjects who constitutes the control group. Nutritional status was evaluated using the malnutrition inflammation score (MIS). Muscle wasting in the present study was evaluated using the lean tissue index (LTI) as assessed by the body composition monitor (BCM). Rectus Femoris Muscle (RFM) thickness was also measured as indicator for nutritional status of patient.

RESULTS

The present study included 60 HD patients, and ageand sex-matched healthy controls. Patients expressed significantly higher myostatin levels when compared to controls [median (IQR): 221.3 (153.5-688.2) versus 144.8 (97.0-281.7), p < 0.001]. According to MIS, patients were classified into those with no/mild malnutrition (n = 22) and others with moderate/severe malnutrition (n = 38). Comparison between the two subgroups revealed that the former group had significantly lower myostatin levels [167.7 (150.3-236.3) versus 341.7 (160.9-955.9), p = 0.004]. According to LTI, patients were classified into those with muscle wasting (n = 23) and others without muscle wasting (n = 37). Comparative analysis showed that patients in the former group had significantly higher myostatin levels [775.1 (325.1-2133.7) versus 161.8 (142.6-302.3), p < 0.001].

CONCLUSIONS

Myostatin seems to be a promising marker for identification of malnutrition and muscle wasting in HD patients.

[GDF5: a therapeutic candidate for combating sarcopenia]

Sarcopenia is a complex age-related muscular disease affecting 10 to 16 % of people over 65 years old. It is characterized by excessive loss of muscle mass and strength. Despite a plethora of studies aimed at understanding the physiological mechanisms underlying this pathology, the pathophysiology of sarcopenia remains poorly understood. To date, there is no pharmacological treatment for this disease. In this context, our team develop therapeutic approaches based on the GDF5 protein to counteract the loss of muscle mass and function in various pathological conditions, including sarcopenia. After deciphering one of the molecular mechanisms governing GDF5 expression, we have demonstrated the therapeutic potential of this protein in the preservation of muscle mass and strength in aged mice.

Anabolic Resistance in the Pathogenesis of Sarcopenia in the Elderly: Role of Nutrition and Exercise in Young and Old People

The development of sarcopenia in the elderly is associated with many potential factors and/or processes that impair the renovation and maintenance of skeletal muscle mass and strength as ageing progresses. Among them, a defect by skeletal muscle to respond to anabolic stimuli is to be considered. Common anabolic stimuli/signals in skeletal muscle are hormones (insulin, growth hormones, IGF-1, androgens, and β-agonists such epinephrine), substrates (amino acids such as protein precursors on top, but also glucose and fat, as source of energy), metabolites (such as β-agonists and HMB), various biochemical/intracellular mediators), physical exercise, neurogenic and immune-modulating factors, etc. Each of them may exhibit a reduced effect upon skeletal muscle in ageing. In this article, we overview the role of anabolic signals on muscle metabolism, as well as currently available evidence of resistance, at the skeletal muscle level, to anabolic factors, from both in vitro and in vivo studies. Some indications on how to augment the effects of anabolic signals on skeletal muscle are provided.

Muscle-Brain crosstalk in cognitive impairment

Sarcopenia is an age-related, involuntary loss of skeletal muscle mass and strength. Alzheimer's disease (AD) is the most common cause of dementia in elderly adults. To date, no effective cures for sarcopenia and AD are available. Physical and cognitive impairments are two major causes of disability in the elderly population, which severely decrease their quality of life and increase their economic burden. Clinically, sarcopenia is strongly associated with AD. However, the underlying factors for this association remain unknown. Mechanistic studies on muscle-brain crosstalk during cognitive impairment might shed light on new insights and novel therapeutic approaches for combating cognitive decline and AD. In this review, we summarize the latest studies emphasizing the association between sarcopenia and cognitive impairment. The underlying mechanisms involved in muscle-brain crosstalk and the potential implications of such crosstalk are discussed. Finally, future directions for drug development to improve age-related cognitive impairment and AD-related cognitive dysfunction are also explored.

Extra Virgin Olive Oil (EVOO), a Mediterranean Diet Component, in the Management of Muscle Mass and Function Preservation

Aging results in a progressive decline in skeletal muscle mass, strength and function, a condition known as sarcopenia. This pathological condition is due to multifactorial processes including physical inactivity, inflammation, oxidative stress, hormonal changes, and nutritional intake. Physical therapy remains the standard approach to treat sarcopenia, although some interventions based on dietary supplementation are in clinical development. In this context, thanks to its known anti-inflammatory and antioxidative properties, there is great interest in using extra virgin olive oil (EVOO) supplementation to promote muscle mass and health in sarcopenic patients. To date, the molecular mechanisms responsible for the pathological changes associated with sarcopenia remain undefined; however, a complete understanding of the signaling pathways that regulate skeletal muscle protein synthesis and their behavior during sarcopenia appears vital for defining how EVOO might attenuate muscle wasting during aging. This review highlights the main molecular players that control skeletal muscle mass, with particular regard to sarcopenia, and discusses, based on the more recent findings, the potential of EVOO in delaying/preventing loss of muscle mass and function, with the aim of stimulating further research to assess dietary supplementation with EVOO as an approach to prevent or delay sarcopenia in aging individuals.

Metabolic Pathways and Ion Channels Involved in Skeletal Muscle Atrophy: A Starting Point for Potential Therapeutic Strategies

Skeletal muscle tissue has the important function of supporting and defending the organism. It is the largest apparatus in the human body, and its function is important for contraction and movements. In addition, it is involved in the regulation of protein synthesis and degradation. In fact, inhibition of protein synthesis and/or activation of catabolism determines a pathological condition called muscle atrophy. Muscle atrophy is a reduction in muscle mass resulting in a partial or complete loss of function. It has been established that many physiopathological conditions can cause a reduction in muscle mass. Nevertheless, it is not well known that the molecular mechanisms and signaling processes caused this dramatic event. There are multiple concomitant processes involved in muscle atrophy. In fact, the gene transcription of some factors, oxidative stress mechanisms, and the alteration of ion transport through specific ion channels may contribute to muscle function impairment. In this review, we focused on the molecular mechanisms responsible for muscle damage and potential drugs to be used to alleviate this disabling condition.

Muscle Wasting in Chronic Kidney Disease: Mechanism and Clinical Implications—A Narrative Review

Muscle wasting, known to develop in patients with chronic kidney disease (CKD), is a deleterious consequence of numerous complications associated with deteriorated renal function. Muscle wasting in CKD mainly involves dysregulated muscle protein metabolism and impaired muscle cell regeneration. In this narrative review, we discuss the cardinal role of the insulin-like growth factor 1 and myostatin signaling pathways, which have been extensively investigated using animal and human studies, as well as the emerging concepts in microRNA- and gut microbiota-mediated regulation of muscle mass and myogenesis. To ameliorate muscle loss, therapeutic strategies, including nutritional support, exercise programs, pharmacological interventions, and physical modalities, are being increasingly developed based on advances in understanding its underlying pathophysiology.