Skeletal muscle loss phenotype in cirrhosis: A nationwide analysis of hospitalized patients

Alcohol and Skeletal Muscle in Health and Disease

PURPOSE

Alcohol-related myopathy is one of the earliest alcohol-associated pathological tissue changes that is progressively exacerbated by cumulative long-term alcohol misuse. Acute and chronic alcohol use leads to changes in skeletal muscle mass and function. As discussed in this evidence-based review, alcohol-mediated mechanisms are multifactorial with effects on anabolic and catabolic signaling, mitochondrial bioenergetics, extracellular matrix remodeling, and epigenomic alterations. However, systematic studies are limited, especially regarding the acute effects of alcohol on skeletal muscle.

SEARCH METHODS

This review focuses on peer-reviewed manuscripts published between January 2012 and November 2022 using the search terms "alcohol" or "ethanol" and "skeletal muscle" in MEDLINE, PubMed, and Web of Science using EndNote reference management software.

SEARCH RESULTS

Eligible manuscripts included full-length research papers that discussed acute and chronic effects of alcohol on skeletal muscle mass and function in both clinical and preclinical studies. The review also includes alcohol-mediated skeletal muscle effects in the context of comorbidities. The three databases together yielded 708 manuscripts. Of these, the authors excluded from this review 548 papers that did not have "alcohol" or "muscle" in the title and 64 papers that were duplicates or did not discuss skeletal muscle. Thus, of all the manuscripts considered for this review, 96 are included and 612 are excluded. Additionally, relevant papers published earlier than 2012 are included to provide context to the review.

DISCUSSION AND CONCLUSIONS

Both acute and chronic alcohol use decrease protein synthesis and increase protein degradation. Alcohol also impairs mitochondrial function and extracellular matrix remodeling. However, there is a gap in the literature on the known alcohol-mediated mechanisms, including senescence, role of immune activation, and interorgan communication, on the development of alcohol-related myopathy. With increased life expectancy, changing alcohol use patterns, and increasing frequency of alcohol use among females, current observational studies are needed on the prevalence of alcohol-related myopathy. Additionally, the compounding effects of acute and chronic alcohol use on skeletal muscle with aging or exercise, in response to injury or disuse, and in the context of comorbidities including diabetes and human immunodeficiency virus (HIV), call for further investigation. Though evidence suggests that abstinence or reducing alcohol use can improve muscle mass and function, they are not restored to normal levels. Hence, understanding the pathophysiological mechanisms can help in the design of therapeutic strategies to improve skeletal muscle health.

Identification of a novel immune-related transcriptional regulatory network in sarcopenia

BACKGROUND

Sarcopenia is highly prevalent in elderly individuals and has a significant adverse effect on their physical health and quality of life, but the mechanisms remain unclear. Studies have indicated that transcription factors (TFs) and the immune microenvironment play a vital role in skeletal muscle atrophy.

METHODS

RNA-seq data of 40 muscle samples were downloaded from the GEO database. Then, differentially expressed genes (DEGs), TFs(DETFs), pathways(DEPs), and the expression of immune gene sets were identified with limma, edgeR, GO, KEGG, ORA, GSVA, and ssGSEA. Furthermore, the results above were integrated into coexpression analysis by Pearson correlation analysis (PCA). Significant coexpression patterns were used to construct the immune-related transcriptional regulatory network by Cytoscape and potential medicine targeting the network was screened by Connectivity Map. Finally, the regulatory mechanisms and RNA expression of DEGs and DETFs were identified by multiple online databases and RT‒qPCR.

RESULTS

We screened 808 DEGs (log2 fold change (FC) > 1 or <  - 1, p < 0.05), 4 DETFs (log2FC > 0.7 or <  - 0.7, p < 0.05), 304 DEPs (enrichment scores (ES) > 1 or <  - 1, p < 0.05), and 1208 differentially expressed immune genes sets (DEIGSs) (p < 0.01). Based on the results of PCA (correlation coefficient (CC) > 0.4 or <  - 0.4, p < 0.01), we then structured an immune-related network with 4 DETFs, 9 final DEGs, 11 final DEPs, and 6 final DEIGSs. Combining the results of online databases and in vitro experiments, we found that PAX5-SERPINA5-PI3K/Akt (CC ≤ 0.444, p ≤ 0.004) was a potential transcriptional regulation axis, and B cells (R = 0.437, p = 0.005) may play a vital role in this signal transduction. Finally, the compound of trichostatin A (enrichment = -0.365, specificity = 0.4257, p < 0.0001) might be a potential medicine for sarcopenia based on the PubChem database and the result of the literature review.

CONCLUSIONS

We first identified immune-related transcriptional regulatory network with high-throughput RNA-seq data in sarcopenia. We hypothesized that PAX5-SERPIAN5-PI3K/Akt axis is a potential mechanism in sarcopenia and that B cells may play a vital role in this signal transduction. In addition, trichostatin A might be a potential medicine for sarcopenia.

Sarcopenia in cirrhosis: epidemiology, diagnosis, management and prognosis

PURPOSE OF REVIEW

With the development of many international guidelines, research on sarcopenia has increased rapidly, showing that sarcopenia is predictive of adverse outcomes, including increased mortality and impaired mobility, in patients with cirrhosis. The purpose of this article is to review the current evidence concerning the epidemiology, diagnosis, management and predictive value of sarcopenia on the prognosis of patients with cirrhosis.

RECENT FINDINGS

Sarcopenia is a frequent and lethal complication of cirrhosis. Currently, abdominal computed tomography imaging is the most commonly used method to diagnose sarcopenia. In clinical practice, assessing muscle strength and physical performance, such as by measuring handgrip strength and gait speed, is of increasing interest. In addition to the necessary pharmacological therapy, adequate intake of protein, energy and micronutrients, as well as regular moderate-intensity exercise, can help to minimize sarcopenia. Sarcopenia has been shown to be a strong predictor of prognosis in patients with severe liver disease.

SUMMARY

A global consensus is needed on the definition and operational parameters for the diagnosis of sarcopenia. Further research should focus on developing standardized screening, management and treatment protocols for sarcopenia. Adding sarcopenia to existing models may better exploit the effect of sarcopenia on prognosis in patients with cirrhosis, which should be investigated further.

Osteosarcopenia in NAFLD/MAFLD: An Underappreciated Clinical Problem in Chronic Liver Disease

Chronic liver disease (CLD), including non-alcoholic fatty liver disease (NAFLD) and its advanced form, non-alcoholic steatohepatitis (NASH), affects a significant portion of the population worldwide. NAFLD is characterised by fat accumulation in the liver, while NASH is associated with inflammation and liver damage. Osteosarcopenia, which combines muscle and bone mass loss, is an emerging clinical problem in chronic liver disease that is often underappreciated. The reductions in muscle and bone mass share several common pathophysiological pathways; insulin resistance and chronic systemic inflammation are the most crucial predisposing factors and are related to the presence and gravity of NAFLD and to the worsening of the outcome of liver disease. This article explores the relationship between osteosarcopenia and NAFLD/MAFLD, focusing on the diagnosis, prevention and treatment of this condition in patients with CLD.

Prevalence and prognosis of Computed-Tomography defined sarcopenia in Tunisian cirrhotic patients

INTRODUCTION

Sarcopenia is an underdiagnosed and understudied complication of cirrhosis, especially in patients not undergoing liver transplantation.

AIM

To evaluate the prevalence and prognostic impact of radiological sarcopenia in non-transplanted cirrhotic patients.

METHODS

Longitudinal retrospective study including cirrhotic patients explored by an abdominal CT scan, over a period of 6 years, in a single gastroenterology department in Tunisia. Sarcopenia was defined according to transversal psoas muscle thickness normalized to height (TPMT/h) in the sagittal CT slice. Two groups were defined: Group 1 with sarcopenia (TPMT/h <16.8mm/m); and Group 2 without sarcopenia (TPMT/h ≥16.8mm/m).

RESULTS

Seventy patients were included (mean age=62 years). The mean MELD score was 12.81 and the mean TPMT/h of 13.56 mm/m. Forty-four patients were sarcopenic (63%). When included, the 2 groups' baseline characteristics were comparable except for women predominance and refractory ascites in group 1. After an average of 21-month follow-up, sarcopenia was associated with a higher number of complications per patient (p=0.013) and a longer average hospital stay duration per patient (p=0.001). Overall survival was significantly decreased in sarcopenic patients (p=0.035). Survival rates at 6 months, 1 year, and 2 years were respectively 42%, 30%, and 24% in Group 1 versus 67%, 40%, and 27% in Group 2. Sarcopenia was an independent factor of mortality in multivariate analysis (OR=2.5; 95% IC [1.02-6.16]; p=0.045).

CONCLUSION

Sarcopenia is frequent and an independent poor prognostic factor in cirrhosis. TPMT/h is an easy and often available method for sarcopenia diagnosis.

Research Note: Expression of IGF-1 and IGF-1 Receptor Proteins in Skeletal Muscle Fiber Types in Chickens with Hepatic Fibrosis

We investigated the expression of insulin-like growth factor 1 (IGF-1) and IGF-1 type 1 receptor (IGF-1R) in skeletal muscle fiber types in chickens with hepatic fibrosis induced by bile duct ligation (BDL). Eleven hens, approximately 104 weeks old, were randomly assigned to BDL (n = 4) and sham surgery (SHAM; n = 7) groups. In BDL hens, histopathology revealed marked bile duct proliferation and liver fibrosis. The cross-sectional area (CSA) of myofibers from both the pectoralis (PCT) muscles significantly decreased in the BDL group compared with the SHAM group (P < 0.01). In contrast, the CSA of myofibers from the femorotibialis lateralis (FTL) muscle did not decrease in the BDL group. Type I fibers were large, round, and hypertrophic. Elongated type IIA and IIB fibers were also present. For IGF-1 immunostaining, the immunoreaction intensity was higher in the PCT in the BDL group than the SHAM group. Within the BDL group, type I fibers from FTL had a stronger immunoreaction intensity than the type II fibers. For IGF-1R immunostaining, the intensity of the immunoreactions was similar within the PCT in the BDL group compared with the SHAM group. For FTL, type I fibers had stronger reactions to IGF-1R than type II fibers in the BDL group. These results suggest that type I fibers express both IGF-1 and IGF-1R and become hypertrophic in chickens with hepatic fibrosis.

Changes in Serum Myostatin Levels in Alcoholic Hepatitis Correlate with Improvement in MELD

BACKGROUND

Alcoholic hepatitis (AH) is a serious clinical syndrome often associated with muscle wasting. Myostatin, a member of the transforming growth factor-β superfamily, has been studied in diseases with muscle wasting; however, the role of myostatin in AH is unknown.

AIMS

To investigate the association between myostatin, clinical variables, and outcomes in AH.

METHODS

We analyzed data for cases of AH and controls of heavy drinkers (HD) in TREAT001 (NCT02172898) with serum myostatin levels (AH: n = 131, HD: n = 124). We compared characteristics between the two groups at baseline, 30, and 90 days and explored correlations between myostatin and clinical variables. We then modeled the relationship of myostatin to other variables, including mortality.

RESULTS

Baseline median myostatin was lower in AH compared to HD (males: 1.58 vs 3.06 ng/ml, p < 0.001; females: 0.84 vs 2.01 ng/ml, p < 0.001). In multivariable linear regression, bilirubin, WBC, and platelet count remained negatively correlated with myostatin in AH. AH females who died at 90 days had significantly lower myostatin, but in a multivariable logistic model with MELD and myostatin, only MELD remained significantly associated with 90-day mortality. During 1-year follow-up, AH cases (n = 30) demonstrated an increase in myostatin (mean, 1.73 ng/ml) which correlated with decreasing MELD scores (ρ = - 0.42, p = 0.01).

CONCLUSIONS

Myostatin levels are significantly lower in AH compared to HD and are negatively correlated with total bilirubin, WBC, and platelet count. Myostatin increased as patients experienced decreases in MELD. Overall, myostatin demonstrated a dynamic relationship with AH outcomes and future studies are needed to understand the prognostic role of myostatin in AH.

Clinical impact of compound sarcopenia in hospitalized older adult patients with heart failure

OBJECTIVES

Skeletal muscle loss or sarcopenia is a frequent complication in heart failure (HF) and contributes to adverse clinical outcomes. We evaluated if age (primary) and chronic disease (secondary) related sarcopenia, that we refer to as compound sarcopenia, impacts clinical outcomes in hospitalized patients with HF.

DESIGN

Cross-sectional study using hospitalized patient data.

SETTING

Data from the Agency for Healthcare Research and Quality through the Healthcare Cost and Utilization Project (HCUP).

PARTICIPANTS

Hospitalized adult patients with a primary or secondary diagnosis of HF (n = 64,476) and a concurrent random 2% sample of general medical population (GMP; n = 322,217) stratified by age (<50 years of age [y], 51-65y, >65y) from the Nationwide Inpatient Sample (NIS) database (years 2010-2014).

MEASUREMENTS

In-hospital mortality, length of stay (LoS), cost of hospitalization per admission (CoH), comorbidities and discharge disposition, with and without muscle loss phenotype, were analyzed. Muscle loss phenotype was defined using a comprehensive code set from international classification of diseases-9 (ICD-9).

RESULTS

Muscle loss phenotype was observed in 8673 (13.5%) patients with HF compared to 5213 (1.6%) GMP across all age strata. In patients with HF, muscle loss phenotype was associated with higher mortality, LoS, and CoH. Patients with HF (>65y) and muscle loss phenotype had higher mortality (adjusted OR: 1.81; 95% CI 1.56-2.10), CoH (adjusted OR 1.48; 95% CI 1.44-1.1.52), and LoS (adjusted OR 1.40; 95% CI 1.37-1.43) compared to >65y GMP with muscle loss phenotype.

CONCLUSION

Muscle loss phenotype is more commonly associated with increasing age in hospitalized patients with HF. Clinical outcomes were significantly worse in patients with HF aged >65y compared to younger patients with HF and all age strata in GMP with and without a muscle loss phenotype.

Compound Sarcopenia in Hospitalized Patients with Cirrhosis Worsens Outcomes with Increasing Age

Background: There are limited data on outcomes of older patients with chronic diseases. Skeletal muscle loss of aging (primary sarcopenia) has been extensively studied but the impact of secondary sarcopenia of chronic disease is not as well evaluated. Older patients with chronic diseases have both primary and secondary sarcopenia that we term compound sarcopenia. We evaluated the clinical impact of compound sarcopenia in hospitalized patients with cirrhosis given the increasing number of patients and high prevalence of sarcopenia in these patients. Design: The Nationwide Inpatients Sample (NIS) database (years 2010–2014) was analyzed to study older patients with cirrhosis. Since there is no universal hospital diagnosis code for “muscle loss”, we used a comprehensive array of codes for “muscle loss phenotype” in the international classification of diseases-9 (ICD-9). A randomly selected 2% sample of hospitalized general medical population (GMP) and inpatients with cirrhosis were stratified into 3 age groups based on age-related changes in muscle mass. In-hospital mortality, length of stay (LoS), cost of hospitalization (CoH), comorbidities and discharge disposition were analyzed. Results. Of 517,605 hospitalizations for GMP and 106,835 hospitalizations for treatment of cirrhosis or a cirrhosis-related complication, 207,266 (40.4%) GMP and 29,018 (27.7%) patients with cirrhosis were >65 years old, respectively. Muscle loss phenotype in both GMP and inpatients with cirrhosis 51–65 years old and >65 years old was significantly (p < 0.001 for all) associated with higher mortality, LoS, and CoH compared to those ≤50 years old. Patients >65 years old with cirrhosis and muscle loss phenotype had higher mortality (adjusted OR: 1.06, 95% CI [1.04, 1.08] and CoH (adjusted odds ratio (OR): 1.10, 95% confidence interval (CI) [1.04, 1.08])) when compared to >65 years old GMP with muscle loss phenotype. Muscle loss in younger patients with cirrhosis (≤50 years old) was associated with worse outcomes compared to GMP >65 years old. Non-home discharges (nursing, skilled, long-term care) were more frequent with increasing age to a greater extent in patients with cirrhosis with muscle loss phenotype for each age stratum. Conclusion: Muscle loss is more frequent in older patients with cirrhosis than younger patients with cirrhosis and older GMP. Younger patients with cirrhosis had clinical outcomes similar to those of older GMP, suggesting an accelerated senescence in cirrhosis. Compound sarcopenia in older patients with cirrhosis is associated with higher inpatient mortality, increased LoS, and CoH compared to GMP with sarcopenia.