Sarcopenia and blood myokine levels as prognostic biomarkers in patients with liver cirrhosis or hepatocellular carcinoma

Computed tomography-determined skeletal muscle density predicts 3-year mortality in initial-dialysis patients in China

BACKGROUND

Skeletal muscle mass and quality assessed by computed tomography (CT) images of the third lumbar vertebra (L3) level have been established as risk factors for poor clinical outcomes in several illnesses, but the relevance for dialysis patients is unclear. A few studies have suggested a correlation between CT-determined skeletal muscle mass and quality at the first lumbar vertebra (L1) level and adverse outcomes. Generally, chest CT does not reach beyond L1. We aimed to determine whether opportunistic CT scan (chest CT)-determined skeletal muscle mass and quality at L1 are associated with mortality in initial-dialysis patients.

METHODS

This 3-year multicentric retrospective study included initial-dialysis patients from four centres between 2014 and 2017 in China. Unenhanced CT images of the L1 and L3 levels were obtained to assess skeletal muscle mass [by skeletal muscle index, (SMI), cm2 /m2 ] and quality [by skeletal muscle density (SMD), HU]. Skeletal muscle measures at L1 were compared with those at L3. The sex-specific optimal cutoff values of L1 SMI and L1 SMD were determined in relation to all-cause mortality. The outcomes were all-cause death and cardiac death. Cox regression models were applied to investigate the risk factors for death.

RESULTS

A total of 485 patients were enrolled, of whom 257 had both L1 and L3 images. Pearson's correlation coefficient between L1 and L3 SMI was 0.84 (P < 0.001), and that between L1 and L3 SMD was 0.90 (P < 0.001). No significant association between L1 SMI and mortality was observed (P > 0.05). Low L1 SMD (n = 280, 57.73%) was diagnosed based on the optimal cutoff value (<39.56 HU for males and <33.06 HU for females). Multivariate regression analysis revealed that the low L1 SMD group had higher risks of all-cause death (hazard ratio 1.80; 95% confidence interval 1.05-3.11, P = 0.034) and cardiac death (hazard ratio 3.74; 95% confidence interval 1.43-9.79, P = 0.007).

CONCLUSIONS

In initial-dialysis patients, there is high agreement between the L1 and L3 measures for SMI and SMD. Low SMD measured at L1, but not low SMI, is an independent predictor of both all-cause death and cardiac death.

Mechanisms of sarcopenia in liver cirrhosis and the role of myokines

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

Lack of association between serum myonectin levels and sarcopenia in older Asian adults

Myonectin is a muscle-secreted factor that helps maintain homeostasis in the body by regulating several functions, including lipid metabolism. Previous studies suggested that myonectin may play a role in muscle health in an autocrine manner, but its impact on human skeletal muscle is still unclear. We aimed to investigate the relationship of serum myonectin levels with sarcopenia and related muscle parameters. We conducted a cross-sectional study of 142 older adults whose muscle mass, grip strength, gait speed, chair stands, and short physical performance battery (SPPB) were evaluated in the geriatric clinic of a tertiary medical center. Sarcopenia was defined based on Asian-specific cutoff values, and circulating myonectin levels were measured using an enzyme immunoassay. Before and after adjusting for age, sex, and body mass index, the serum myonectin level was not significantly different when the patients were stratified by status of sarcopenia, muscle mass, muscle strength, and physical performance. Furthermore, whether given as a continuous variable or divided into quartile groups, the serum myonectin level had no association with the skeletal muscle mass, grip strength, gait speed, chair stand test, or SPPB score. Our findings did not confirm the potential role of myonectin in muscle metabolism observed in experimental research. Thus, serum myonectin levels cannot predict the risk of sarcopenia in older Asian adults.

Serum Myostatin among Excessive Drinkers

Myostatin acts as a negative regulator of muscle growth. Its effect on fat mass is subject to debate. Among alcoholics, there is a high prevalence of muscle atrophy, and increased fat deposition has been also described in these patients. Myostatin could be involved in these alterations, but its relationships with body composition have been scarcely studied in alcoholic patients. To analyze the behavior of myostatin among alcoholics and its relationship with alcohol intake, liver function, and body composition. We investigated serum myostatin in 59 male patients and 18 controls. Patients were all heavy drinkers admitted with organic complications related to excessive ethanol ingestion. Densitometry analysis was used to assess body composition in 46 patients. Handgrip was assessed in 51 patients. Patients showed lower myostatin values than controls (Z = 3.80; p < 0.001). There was a significant relationship between myostatin and fat at the right leg (ρ = 0.32; p = 0.028), left leg (ρ = 0.32; p = 0.028), trunk (ρ = 0.31, p = 0.038), total fat proport ion (ρ = 0.33, p = 0.026), and gynecoid fat distribution (ρ = 0.40, p = 0.006) but not with lean mass (total lean ρ = 0.07; p = 0.63; trunk lean ρ = 0.03; p = 0.85; lower limbs ρ = 0.08; p = 0.58; upper limbs ρ = 0.04 p = 0.82; android ρ = 0.02; p = 0.88, or gynoid lean mass ρ = 0.20; p = 0.19). In total, 80.43% of patients showed at least one criterion of osteosarcopenic adiposity (OSA). Myostatin was related to OSA obesity. We also observed higher myostatin values among patients with body mass index > 30 kg/m². Serum myostatin was lower among excessive drinkers, and it was related to increased fat deposition among these patients but not to lean mass, handgrip, or bone mineral density.

Interaction between sarcopenia and nonalcoholic fatty liver disease

Sarcopenia and nonalcoholic fatty liver disease (NAFLD) are common health problems related to aging. Despite the differences in their diagnostic methods, several cross-sectional and longitudinal studies have revealed the close link between sarcopenia and NAFLD. Sarcopenia and NAFLD are linked by several shared pathogenetic mechanisms, including insulin resistance, hormonal imbalance, systemic inflammation, myostatin and adiponectin dysregulation, nutritional deficiencies, and physical inactivity, thus implicating a bidirectional relationship between sarcopenia and NAFLD. However, there is not sufficient data to support a direct causal relationship between sarcopenia and NAFLD. Moreover, it is currently difficult to conclude whether sarcopenia is a risk factor for nonalcoholic steatohepatitis (NASH) or is a consequence of NASH. Therefore, this review intends to touch on the shared common mechanisms and the bidirectional relationship between sarcopenia and NAFLD.

Association between Regional Body Muscle Mass and Non-Alcoholic Fatty Liver Disease: An Observational Study Using Data from the REACTION Study

Background and aims: Regional muscle distribution is associated with abdominal obesity and metabolic syndrome. However, the relationship between muscle distribution and nonalcoholic fatty liver disease (NAFLD) remains unclear. This study was to determine the relationship between regional muscle distribution and the risk and severity of NAFLD. Methods: This cross-sectional study ultimately included 3161 participants. NAFLD diagnosed by ultrasonography was classified into three groups (non, mild, and moderate/severe). We estimated the regional body muscle mass (lower limbs, upper limbs, extremities, and trunk) through multifrequency bioelectrical impedance analysis (BIA). The relative muscle mass was defined as the muscle mass adjusted for the body mass index (BMI). Results: NAFLD participants accounted for 29.9% (945) of the study's population. Individuals with a higher lower limb, extremity, and trunk muscle mass had a lower risk of NAFLD (p < 0.001). Patients with moderate/severe NAFLD had a lower muscle mass of the lower limbs and trunk than patients with mild NAFLD (p < 0.001), while the muscle mass of the upper limbs and extremities did not differ significantly between the two groups. Moreover, similar results were found for both sexes and among different age groups. Conclusions: A higher muscle mass of the lower limbs, extremities, and trunk was negatively associated with the risk of NAFLD. A lower muscle mass of the limbs and trunk was inversely associated with the severity of NAFLD. This study provides a new theoretical basis for the development of individualized exercise prescriptions for the prevention of NAFLD in non-NAFLD patients.

Contribution of organokines in the development of NAFLD/NASH associated hepatocellular carcinoma

Globally the incidence of hepatocellular carcinoma (HCC) is on an upsurge. Evidence is accumulating that liver disorders like nonalcoholic fatty liver disease (NAFLD) and its more progressive form nonalcoholic steatohepatitis (NASH) are associated with increased risk of developing HCC. NAFLD has a prevalence of about 25% and 50%-90% in obese population. With the growing burden of obesity epidemic worldwide, HCC presents a major healthcare burden. While cirrhosis is one of the major risk factors of HCC, available literature suggests that NAFLD/NASH associated HCC also develops in minimum or noncirrhotic livers. Therefore, there is an urgent need to understand the pathogenesis and risk factors associated with NAFLD and NASH related HCC that would help in early diagnosis and favorable prognosis of HCC secondary to NAFLD. Adipokines, hepatokines and myokines are factors secreted by adipocytes, hepatocytes and myocytes, respectively, playing essential roles in cellular homeostasis, energy balance and metabolism with autocrine, paracrine and endocrine effects. In this review, we endeavor to focus on the role of these organokines in the pathogenesis of NAFLD/NASH and its progression to HCC to augment the understanding of the factors stimulating hepatocytes to acquire a malignant phenotype. This shall aid in the development of novel therapeutic strategies and tools for early diagnosis of NAFLD/NASH and HCC.

Regulator 1-Peroxisome Proliferator-Activated Receptor-γ Coactivator-1α Signaling Pathway in Investigating the Pathological Characteristics and Molecular Mechanism of Liver Cirrhosis Complicated by Acute Kidney Injury

The objective of this study was to investigate the molecular mechanism of the histopathological characteristics of liver cirrhosis (LC) complicated with acute kidney injury (AKI) and the signaling pathway of silent information regulator 1 (SIRT1)-peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) during the pathogenesis of LC. 20 healthy male rats with AKI complicated by laparoscopic cholecystectomy were selected and divided randomly into control group (C group), lipopolysaccharide (LPS) group, bile duct ligation (BDL) group, and model group (lipopolysaccharide+BDL) (D group). The indexes of all the rats were determined, including serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), sarcoplasmic enzyme (Scr), and blood urea nitrogen (BUN); the SIRT1 and PGC-1α expressions in renal tissues of rats from each group was detected. Results showed that the AST and ALT levels in BDL group and D group were higher markedly than those before surgery (P < 0.05). The serum levels of Scr and BUN in D group 4 hours after LPS injection increased hugely compared with before injection (P < 0.05). Compared with BDL group, the protein levels of SIRT1 and PGC-1α in renal tissue of group D were decreased sharply (P < 0.05), and the SIRT1 protein expression was positively correlated with PGC-1α (r = 0.836 and P < 0.01). When LC were complicated with AKI, SIRT1 activity was reduced and PGC-1α expression was inhibited. Moreover, SIRT1-PGC-1α signaling pathway played a protective role in pathogenesis of LC complicated with AKI.

Association between serum TNF-α and sarcopenia in liver cirrhosis

Background/Aims

Sarcopenia is an independent prognostic factor of liver cirrhosis (LC). However, the association between LC-related systemic inflammation and sarcopenia is unclear.

Methods

Sprague-Dawley rats were treated with thioacetamide (TAA) or saline as a control. Rifaximin was administered to TAA-induced LC rats. Enzyme-linked immunosorbent assay was performed to measure inflammatory mediators in rat serum. RT-PCR was performed to measure the molecular expression in tissues. Hematoxylin and eosin (H&E) staining and immunohistochemistry were performed to investigate tissue pathology. Serum tumor necrosis factor-α levels, liver stiffness (LS), and the L3 skeletal muscle index (L3SMI) were measured in 60 patients with chronic liver disease.

Results

LC and sarcopenia were successfully induced by TAA. Serum TNF-α levels were increased in LC rats and correlated with myostatin expression, muscle weight, and myofiber diameter. The expression of intestinal occludin and zona occludens-1 was reduced in LC rats and associated with serum TNF-α levels and sarcopenia. In patients with LS ≥7 kPa or sarcopenia, serum TNF-α levels were significantly increased, which was also confirmed when we raised the LS cutoff to 10 kPa. The L3SMI was inversely correlated with serum TNF-α levels in patients with LS ≥7 kPa. TNF-α was reduced by rifaximin, which might have resulted in reduced expression of muscular MuRF1 and myostatin and improvements in myofiber diameters within muscle tissues.

Conclusions

These results suggest that serum TNF-α is associated with LC-related sarcopenia. Rifaximin might be effective in reducing serum TNF-α levels and improving sarcopenia in LC, but these results need to be validated in future studies.

Association of Physical Activity with the Risk of Hepatocellular Carcinoma in Patients with Chronic Hepatitis B

Simple Summary

Although viral replication in patients with a chronic hepatitis B (CHB) infection is effectively suppressed by potent antiviral therapy such as entecavir or tenofovir, the risk of hepatocellular carcinoma (HCC) development in CHB patients cannot be totally eliminated. Thus, control of modifiable risk factors for HCC development such as lifestyle modification is important to minimize the HCC risk. In this study, we analyzed a nationwide population-based cohort to evaluate whether there is a significant association between physical activity and development of HCC in CHB patients treated with entecavir or tenofovir. Results in this study suggest that physical activity was significantly associated with a lower risk of HCC development in CHB patients treated with potent antiviral therapy. Increasing physical activity can have beneficial outcomes on HCC development in CHB patients treated with entecavir or tenofovir.

Abstract

Background and Aims: In the general population, previous studies reported that physical activity was associated with risk of hepatocellular carcinoma (HCC) development. However, it is unclear whether physical activity is associated with risk of HCC development in patients with chronic hepatitis B (CHB). We aimed to elucidate the association between physical activity and risk of HCC development in CHB patients. Methods: This nationwide cohort study involved treatment-naive patients with CHB (n = 9727) who started treatment with entecavir or tenofovir and answered self-reported questionnaires between January 2012 and December 2017, using data from the Korean National Health Insurance Service database. The primary endpoint was development of HCC. Multivariable Cox regression and competing risk analyses were used. Results: During a median follow-up of 3.1 years, cumulative HCC incidence rates were 8.3%. There was an inverse association between physical activity and the risk of HCC (p < 0.001). Patients with 1000–1500 metabolic equivalent task (MET)-min/week, compared to those without physical activity, showed a significantly lower risk of HCC in both patients without cirrhosis (adjusted hazard ratio [aHR] 0.66, p = 0.02) and patients with cirrhosis (aHR 0.61, p = 0.02). In patients who were younger (<60), male, without diabetes, and with high BMI, amounts of physical activity of 1000–1500 MET-min/week showed an inverse association with the risk of HCC (aHR 0.65, 0.63, 0.65, and 0.64, respectively, all p < 0.05). Conclusion: Physical activity was significantly associated with a low risk of HCC in CHB patients treated with entecavir or tenofovir.