The Common Mechanisms of Sarcopenia and NAFLD. Biomed Res Int. 2017;2017:6297651. [PMID: 29387723 PMCID: PMC5745668 DOI: 10.1155/2017/6297651]

Implications of Protein and Sarcopenia in the Prognosis, Treatment, and Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is a common cause of chronic liver disease globally, with prevalence rapidly increasing in parallel with rising rates of obesity and metabolic syndrome. MASLD is defined by the presence of excess fat in the liver, which may induce inflammatory changes and subsequent fibrosis in high-risk patients. Though MASLD occurs frequently, there is still no approved pharmacological treatment, and the mainstay of therapy remains lifestyle modification via dietary changes, enhancement of physical activity, and management of metabolic comorbidities. Most nutrition research and clinical guidance in this disease centers on the reduction in fructose and saturated fat in the diet, although the emerging literature suggests that protein supplementation is important and implicates muscle mass and sarcopenia in disease-related outcomes. This review will assess the current data on these topics, with the goal of defining best practices and identifying research gaps in care.

Association of Uric Acid to Creatinine Ratio with Metabolic Dysfunction-Associated Fatty Liver in Non-Obese Individuals Without Type 2 Diabetes Mellitus

Introduction

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease, which is usually associated with type 2 diabetes mellitus (T2DM) and obesity. However, the incidence of MALFD in non-obese individuals without T2DM is increasing, and the pathogenesis is unclear. Serum uric acid to creatinine ratio (sUA/Cr) can reflect overall metabolic status. This study aims to observe the association between sUA/Cr and MAFLD in non-obese individuals without T2DM.

Methods

A total of 21,996 individuals were included in this study. The subjects were divided into four subgroups: non-obese patients without T2DM, obese patients without T2DM, non-obese patients with T2DM, and obese patients with T2DM. Logistic regression analyzed the correlation between sUA/Cr and MAFLD subgroups. Receiver operating characteristics analyzed the predictive value of sUA/Cr for MAFLD subgroups. The stratified analyses by sex and age were performed.

Results

Non-obese MAFLD individuals without T2DM had higher sUA/Cr levels than their counterparts. sUA/Cr was significantly correlated positively with MAFLD in non-obese patients. Similar results were observed in both males and females and in populations at all age stages (all p<0.01). sUA/Cr was capable of discriminating MAFLD in non-obese individuals without T2DM (AUC: 0.667), especially for patients over 60 years old (AUC: 0.704).

Conclusion

The sUA/Cr ratio was correlated with MAFLD in non-obese patients without T2DM. The predictive value of sUA/Cr for MAFLD was observed. Hence, the sUA/Cr ratio might be given more concern for the risk of MAFLD in non-obese individuals without T2DM.

What Does Sarcopenia Have to Do with Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease. As the second stage of developing steatosis, nonalcoholic hepatitis (NASH) carries the risk of fibrosis, cirrhosis, and hepatocellular carcinoma. Sarcopenia is defined as a condition characterized by a decrease in muscle mass and functional decline. Both NAFLD and sarcopenia are global problems. The pathophysiological mechanisms that link the two entities of the disease are insulin resistance, inflammation, nutritional deficiencies, impairment of myostatin and adiponectin, or physical inactivity. Furthermore, disorders of the gut-liver axis appear to induce the process of developing NAFLD and sarcopenia. The correlations between NAFLD and sarcopenia appear to be bidirectional, so the main objective of the review was to determine the cause-and-effect relationship between the two diseases.

Association between total body muscle percentage and prevalence of non-alcoholic fatty liver disease in Korean adults findings from an 18-year follow-up: a prospective cohort study

BACKGROUND

This study aimed to elucidate the association between total lean muscle mass and the incidence of non-alcoholic fatty liver disease (NAFLD) in the adult Korean population.

METHODS

Utilizing data derived from the 18-year prospective cohort of the Korean Genome and Epidemiology Study, NAFLD was diagnosed via the hepatic steatosis index with an established cutoff value of 36. Lean muscle mass was assessed via bioelectrical impedance analysis and subsequently divided into tertiles. A generalized mixed model with a logit link was employed for repeated measures data analysis, accounting for potential confounders.

RESULTS

Analysis encompassed 7,794 participants yielding 49,177 measurements. The findings revealed a markedly increased incidence of NAFLD in the lower tertiles of muscle mass, specifically, tertile 1 (odds ratio [OR], 20.65; 95% confidence interval [CI], 9.66-44.11) and tertile 2 (OR, 4.57; 95% CI, 2.11-9.91), in comparison to tertile 3. Age-dependent decreases in the OR were observed within the tertile 1 group, with ORs of 10.12 at age of 40 years and 4.96 at age of 80 years. Moreover, each 1%-point increment in total muscle mass corresponded with an estimated OR of 0.87 (95% CI, 0.82-0.93) for NAFLD resolution.

CONCLUSIONS

The study demonstrates a significant association between total muscle mass and NAFLD prevalence among Korean adults. Given the potential endocrine role of muscle mass in NAFLD pathogenesis, interventions aimed at enhancing muscle mass might serve as an effective public health strategy for mitigating NAFLD prevalence.

Impact of skeletal muscle mass evaluating methods on severity of metabolic associated fatty liver disease in non-elderly adults

The study aimed to explore the relationships of skeletal muscle mass with disease severity in metabolic-associated fatty liver disease (MAFLD) patients with different methods. Consecutive subjects undergoing bioelectrical impedance analysis were included. The steatosis grade and liver fibrosis were evaluated by MRI-derived proton density fat fraction and two-dimensional shear wave elastography. The appendicular skeletal muscle mass (ASM) was adjusted by height2 (ASM/H2), weight (ASM/W) and BMI (ASM/BMI). Overall, 2223 subjects (50·5 %, MAFLD; 46·9 %, male) were included, with the mean age 37·4 ± 10·6 years. In multivariate logistic regression analysis, the subjects with the lowest quartile (Q1) of ASM/W or ASM/BMI had higher risk ratios for MAFLD (OR (95 % CI) in male: 2·57 (1·35, 4·89), 2·11(1·22, 3·64); in female: 4·85 (2·33, 10·01), 4·81 (2·52, 9·16), all P < 0·05, all for Q1 v. Q4). The MAFLD patients with lower quartiles of ASM/W had the higher risk OR for insulin resistance (IR), both in male and female (2·14 (1·16, 3·97), 4·26 (1·29, 14·02) for Q4 v. Q1, both P < 0·05). While the significant OR were not observed when ASM/H2 and ASM/BMI were used. There were significant dose-dependent associations between decreased ASM/W as well as ASM/BMI and moderate-severe steatosis (2·85(1·54, 5·29), 1·90(1·09, 3·31), both P < 0·05) in male MAFLD patients. In conclusion, ASM/W is superior to ASM/H2 and ASM/BMI in predicting the degree of MAFLD. A lower ASM/W is associated with IR and moderate-severe steatosis in non-elderly male MAFLD.

Associations between muscle mass, strength, and performance and non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a rising global health issue. The influence of muscle in its pathophysiology has recently gained attention. Our aim was to investigate the association of low muscle mass, strength, and performance with the presence and severity of NAFLD.

METHODS

Patients with metabolic syndrome followed in an outpatient clinic, were consecutively included, between April 1st and December 31st, 2019. Abdominal ultrasound for the diagnosis of NAFLD, NAFLD fibrosis score (NFS) and Fibrosis-4 Index (FIB-4) for determination of significant fibrosis, dual-energy X-ray absorptiometry for calculation of skeletal muscle index (SMI = appendicular skeletal mass / weight x100) and sarcopenic index (SI = appendicular skeletal mass / Body Mass Index), and the Short Physical Performance Battery for muscle strength and performance assessment were performed. Sarcopenia was defined as low muscle strength and low SMI or SI.

RESULTS

A total of 157 patients were included, of which 68.8% had NAFLD, 66.2% low SMI, 50.3% low SI, 16.6% low performance and 11.5% low strength. In patients with NAFLD, prevalence of significant fibrosis by NFS was 15.7%. Low SMI was associated with presence of NAFLD when adjusted for age, sex, type 2 diabetes mellitus, hypertension, and dyslipidemia, but not for body mass index and waist circumference. Low SMI, low SI, and sarcopenia were associated with significant fibrosis in univariate analysis; the small number of events precluded a multivariable analysis.

CONCLUSIONS

Low SMI was associated with NAFLD independently of demographics and comorbidities but not of other parameters of body composition. This contrasts with most studies published on this matter.

Association between Body Composition Contents and Hepatic Fibrosis in Sarcopenic Obesity

It is well established that sarcopenic obesity (SO) is linked to many diseases such as metabolic and non-alcoholic fatty liver diseases, but there is little known about the relationship between SO and hepatic fibrosis progression in chronic liver disease. This study compared body composition contents in patients with non-obesity (NOb) and SO using abdominal magnetic resonance imaging and investigated the relationship between hepatic fibrosis and SO factors. This retrospective study enrolled 60 patients (28 NOb; 32 SO) from June 2014 to December 2020. Patients underwent histopathologic investigation where they classified fibrosis stages based on the Meta-analysis of Histological Data in Viral Hepatitis fibrosis scoring system. Muscle and fat areas at the third lumber vertebra level were assessed. The variation in the areas of muscle (MA), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) among fibrosis stages, and associations between hepatic fibrosis and SO factors, were analyzed. There were significant differences in SAT and VAT (p < 0.001), whereas there was no difference in MA (p = 0.064). There were significant differences in MA/SAT (p = 0.009), MA/VAT (p < 0.001), and MA/(SAT+VAT) (p < 0.001). In all the patients, hepatic fibrosis positively correlated with serum aspartate aminotransferase level (AST, R = 0.324; p = 0.025). Especially in SO patients, hepatic fibrosis closely correlated with body mass index (BMI, R = 0.443; p = 0.011), AST (R = 0.415; p = 0.044), VAT (R = 0.653; p < 0.001), MA/VAT (R = -0.605; p < 0.001), and MA/(SAT+VAT) (R = -0.416; p = 0.018). However, there was no association in NOb patients. This study demonstrated that SO patients had larger SAT and VAT than NOb patients. Hepatic fibrosis in SO positively correlated with body visceral fat composition in combination with BMI and AST level. These findings will be useful for understanding the relationship between the hepatic manifestation of fibrosis and body fat composition in sarcopenia and SO.

The Role of Choline, Soy Isoflavones, and Probiotics as Adjuvant Treatments in the Prevention and Management of NAFLD in Postmenopausal Women

Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition among postmenopausal women that can lead to severe liver dysfunction and increased mortality. In recent years, research has focused on identifying potential lifestyle dietary interventions that may prevent or treat NAFLD in this population. Due to the complex and multifactorial nature of NAFLD in postmenopausal women, the disease can present as different subtypes, with varying levels of clinical presentation and variable treatment responses. By recognizing the significant heterogeneity of NAFLD in postmenopausal women, it may be possible to identify specific subsets of individuals who may benefit from targeted nutritional interventions. The purpose of this review was to examine the current evidence supporting the role of three specific nutritional factors-choline, soy isoflavones, and probiotics-as potential nutritional adjuvants in the prevention and treatment of NAFLD in postmenopausal women. There is promising evidence supporting the potential benefits of these nutritional factors for NAFLD prevention and treatment, particularly in postmenopausal women, and further research is warranted to confirm their effectiveness in alleviating hepatic steatosis in this population.

Comparative analysis of the relationship between four hepatic steatosis indices and muscle mass

Several studies have attempted to validate the relationship between hepatic steatosis and sarcopenia. The crucial limitation is to establish the status of hepatic steatosis by costly or invasive methods. Therefore, several models predicting non-alcoholic fatty liver disease (NAFLD) have been developed but have exhibited heterogeneous results. In this study, we aimed to review and compare four representative models and analyze their relationship with the risk of low muscle mass. Korea National Health and Nutrition Examination Surveys from 2008 to 2011 were used to confirm our hypothesis. Dual-energy X-ray absorptiometry was used to measure the amount of skeletal muscle mass. We used four hepatic steatosis indices: hepatic steatosis index (HSI), Framingham steatosis index (FSI), liver fat score (LFS), and fatty liver index (FLI). Multivariate linear and logistic regressions were used to reveal the relationship between NAFLD and low skeletal muscle index (LSMI). Pairs of FSI-FLI and HSI-FLI exhibited the best and second-best correlations among all possible pairs. The four hepatic steatosis models were associated with increased risk for LSMI. After removing the body mass index effect, HSI and FLI remained robust predictors for LSMI. NAFLD was a significant and potent risk factor for low skeletal muscle.

Using hyperhomocysteinemia and body composition to predict the risk of non-alcoholic fatty liver disease in healthcare workers

Purpose

This study investigated associations between serum homocysteine levels, body composition, and the probability of having nonalcoholic fatty liver disease (NAFLD) in Chinese healthcare workers.

Patients and Methods

A total of 4028 healthcare workers were enrolled in this study, and all underwent a physical examination. Body composition was measured using multifrequency bioelectrical impedance analysis.

Results

There were 1507 NAFLD patients (72.26% male, 27.74% female) and 2521 controls (39.83% male, 60.17% female). Body mass index (BMI), waistline, neck-circumference (NC), abdominal visceral fat area (AVFA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), glucose (Glu), homocysteinemia (hcy) were higher in the NAFLD group than controls. Additionally, the skeletal-muscle was associated with a lower risk of NAFLD, whereas BMI, waistline, NC, hyperhomocysteinemia (HHcy) were associated with a higher risk of NAFLD. The best NC cut-off point for NAFLD was 34.45 cm (sensitivity 83.3% and specificity 83.9%) in women with HHcy, and the best skeletal-muscle content cut-off point for NAFLD was 41.335% (sensitivity 74.2% and specificity 65.6%) in men with HHcy.

Conclusion

Interactions between skeletal-muscle content, NC, and HHcy may affect the incidence of NAFLD in healthcare workers. This may provide a novel approach for diagnosing NAFLD.

Diet was less significant than physical activity in the prognosis of people with sarcopenia and metabolic dysfunction-associated fatty liver diseases: Analysis of the National Health and Nutrition Examination Survey III

BACKGROUND

Sarcopenia is prevalent in metabolic dysfunction-associated fatty liver diseases (MAFLD), and the primary treatment for both diseases is lifestyle modification. We studied how dietary components and physical activity affect individuals with sarcopenia and MAFLD.

MATERIALS AND METHODS

We conducted a study utilizing National Health and Nutrition Examination Survey (NHANES) III (1988-1994) data with Linked Mortality file (through 2019). The diagnosis of fatty liver disease (FLD) was based on ultrasound images revealing moderate and severe steatosis. Using bioelectrical measures, sarcopenia was assessed. Using self-report data, dietary intake and physical activity levels were evaluated.

RESULTS

Among 12,259 participants, 2,473 presented with MAFLD, and 290 of whom had sarcopenia. Higher levels of physical activity (odds ratio [OR] = 0.51 [0.36-0.95]) and calorie (OR = 0.58 [0.41-0.83]) intake reduced the likelihood of sarcopenia in MAFLD patients. During a median follow-up period of 15.3 years, 1,164 MAFLD and 181 MAFLD patients with sarcopenia perished. Increased activity levels improved the prognosis of patients with sarcopenia (Insufficiently active, HR = 0.75 [0.58-0.97]; Active, HR = 0.64 [0.48-0.86]), which was particularly pronounced in older patients.

CONCLUSION

In the general population, hyperglycemia was highly related to MAFLD prognosis. Physical inactivity and a protein-restricted diet corresponded to sarcopenia, with physical inactivity being connected to poor outcomes. Adding protein supplements would be beneficial for older people with sarcopenia who are unable to exercise due to frailty, while the survival benefits were negligible.

Nonalcoholic fatty liver disease and accelerated loss of skeletal muscle mass: A longitudinal cohort study

BACKGROUND AND AIMS

Whether subjects with NAFLD are at increased risk of sarcopenia is not well established.

APPROACH AND RESULTS

This is a cohort study of 52,815 men and women of 20 years of age or older who underwent at least two health check-up exams with bioelectrical impedance analysis and abdominal ultrasound imaging. Bioelectrical impedance analysis was used to calculate appendicular skeletal muscle mass (ASM). NAFLD was assessed by ultrasonography, and its severity was assessed by the NAFLD fibrosis score (NFS). We estimated the 5-year change in ASM comparing participants with and without NAFLD at baseline using mixed linear models. The 5-year change in ASM in participants without and with NAFLD was -225.2 g (95% CI -232.3, -218.0) and -281.3 g (95% CI -292.0, -270.6), respectively (p < 0.001). In multivariable adjusted analysis, the difference in 5-year change in ASM comparing participants with and without NAFLD was -39.9 g (95% CI -53.1, -26.8). When participants with NAFLD were further divided by NAFLD severity, ASM loss was much faster in participants with NAFLD with intermediate to high NFS than in those with low NFS.

CONCLUSIONS

Participants with NAFLD were at increased risk of sarcopenia, indicated by faster loss of skeletal muscle mass. Patients with NAFLD may need screening and early intervention to mitigate skeletal muscle mass loss.

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.

Metabolic aspects of hepatitis C virus

Many metabolic factors are associated with chronic hepatitis C virus (HCV) infection and can influence the course of the illness and impact the progression of liver and non-liver-related diseases through complex interactions. Several of these factors impact the course of chronic HCV (CHC) and result in the conceptual translation of CHC from a localized to systemic disease. Besides the traditional liver manifestations associated with CHC infection, such as cirrhosis and hepatocellular carcinoma, various extrahepatic disorders are associated with HCV infection, including atherosclerosis, glucose and lipid metabolic disturbances, alterations in the iron metabolic pathways, and lymphoproliferative diseases. The coexistence of metabolic disorders and CHC is known to influence the chronicity and virulence of HCV and accelerates the progression to liver fibrosis and hepatocellular carcinoma. Insulin resistance is one of the key factors that have a tremendous metabolic impact on CHC. Therefore, there is a great need to properly evaluate patients with CHC infection and correct the modifiable metabolic risk factors. Furthermore, patients with HCV who achieved a sustained virological response showed an overall improvement in glucose metabolism, but the exact evidence still requires further studies with long-term follow-up. This review delineates the most recent evidence on the main metabolic factors associated with CHC and the possible influence of chronic HCV infection on metabolic features.

Association of Muscle Strength with Non-Alcoholic Fatty Liver Disease in Korean Adults

Sarcopenia is known to be associated with non-alcoholic fatty liver disease (NAFLD). However, few studies have revealed the association between muscle strength and prevalence of NAFLD. We investigated the association by using relative handgrip strength in a nationwide cross-sectional survey. The participants were recruited from the Korean National Health and Nutrition Examination Surveys (KNHANES). A total of 27,531 subjects from the KNHANES were selected in our study. We used normalized handgrip strength, which is called relative handgrip strength. The index was defined as handgrip strength divided by BMI. These subjects were divided into quartile groups according to relative handgrip strength. NAFLD was defined as hepatic steatosis index >36. Multinomial logistic regression was analysed to investigate the association between relative handgrip strength with prevalence of NAFLD. The mean age of study population was 45.8 ± 0.3 in men, and 48.3 ± 0.2 in women. The proportion of males was 37.5%. In multiple linear regression, relative handgrip strength was inversely associated with HSI index (Standardized β = −0.70; standard error (SE), 0.08; p < 0.001 in men, Standardized β = −0.94; standard error (SE), 0.07; p < 0.001 in women). According to the logistic regression model, the prevalence of NAFLD decreased with quartile 4 groups in relative handgrip strength, compared with quartile 1 groups (OR 0.42 [0.32–0.55] in men; OR 0.30 [0.22–0.40] in women). Relative handgrip strength, used as a biomarker of sarcopenia, is independently inversely associated with NAFLD.

Impact of Sarcopenia and Myosteatosis in Non-Cirrhotic Stages of Liver Diseases: Similarities and Differences across Aetiologies and Possible Therapeutic Strategies

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

High-Fructose, High-Fat Diet Alters Muscle Composition and Fuel Utilization in a Juvenile Iberian Pig Model of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a serious metabolic condition affecting millions of people worldwide. A “Western-style diet” has been shown to induce pediatric NAFLD with the potential disruption of skeletal muscle composition and metabolism. To determine the in vivo effect of a “Western-style diet” on pediatric skeletal muscle fiber type and fuel utilization, 28 juvenile Iberian pigs were fed either a control diet (CON) or a high-fructose, high-fat diet (HFF), with or without probiotic supplementation, for 10 weeks. The HFF diets increased the total triacylglycerol content of muscle tissue but decreased intramyocellular lipid (IMCL) content and the number of type I (slow oxidative) muscle fibers. HFF diets induced autophagy as assessed by LC3I and LC3II, and inflammation, as assessed by IL-1α. No differences in body composition were observed, and there was no change in insulin sensitivity, but HFF diets increased several plasma acylcarnitines and decreased expression of lipid oxidation regulators PGC1α and CPT1, suggesting disruption of skeletal muscle metabolism. Our results show that an HFF diet fed to juvenile Iberian pigs produces a less oxidative skeletal muscle phenotype, similar to a detraining effect, and reduces the capacity to use lipid as fuel, even in the absence of insulin resistance and obesity.

Risk stratification using sarcopenia status among subjects with metabolic dysfunction-associated fatty liver disease

BACKGROUND

Sarcopenia is a significant indicator of the severity of non-alcoholic fatty liver disease. We investigated whether sarcopenia could identify subgroups with different risk of liver fibrosis and atherosclerotic cardiovascular disease (ASCVD) among subjects with metabolic dysfunction-associated fatty liver disease (MAFLD).

METHODS

Subjects from the Korea National Health and Nutrition Examination Survey 2008-2011 were selected (n = 8361). Sarcopenia was defined using the sarcopenia index. Hepatic steatosis was defined as a fatty liver index ≥30. Significant liver fibrosis was defined as a fibrosis-4 index (FIB-4) ≥2.67 or the highest quartile of non-alcoholic fatty liver disease fibrosis score (NFS). High probability of ASCVD was defined as ASCVD risk score >10%.

RESULTS

The mean age was 48.5 ± 15.6 years, and 42.6% of subjects were male. The prevalence of MAFLD was 37.3% (n = 3116 of 8361), and the proportion of sarcopenic subjects was 9.9% among those with MAFLD. After adjusting for confounders, the risk of significant liver fibrosis significantly increased from non-sarcopenic subjects with MAFLD [odds ratio (OR) = 1.57 by FIB-4 and 2.13 by NFS] to sarcopenic subjects with MAFLD (OR = 4.51 by FIB-4 and 5.72 by NFS), compared with subjects without MAFLD (all P < 0.001). The risk for high probability of ASCVD significantly increased from non-sarcopenic subjects with MAFLD (OR = 1.47) to sarcopenic subjects with MAFLD (OR = 4.08), compared with subjects without MAFLD (all P < 0.001).

CONCLUSIONS

The risks of significant liver fibrosis and ASCVD differed significantly according to sarcopenic status among subjects with MAFLD. An assessment of sarcopenia might be helpful in risk stratification among subjects with MAFLD.

Impedance-based measures of muscle mass can be used to predict severity of hepatic steatosis in pediatric nonalcoholic fatty liver disease

OBJECTIVES

The objective of this study was to investigate the association between measures of body composition based on bioelectrical impedance analysis (BIA) and histologic severity of liver disease in a pediatric cohort with nonalcoholic fatty liver disease (NAFLD).

METHODS

This was a cross-sectional study of patients < 20 y old with histologically confirmed NAFLD followed in our Steatohepatitis Center from 2017 to 2019. Contemporaneous body-composition data were obtained using a multifrequency octopolar BIA device (InBody 370, InBody, Seoul, South Korea). BIA data collected were skeletal muscle mass, appendicular muscle mass, and percentage body fat. Skeletal and appendicular muscle mass were corrected for height (dividing by the square of height), generating their respective indices. Univariate linear and logistic regression, followed by multivariable logistic regression analyses, were used.

RESULTS

Of the 79 children included (27% female, 73% male; 38% Hispanic; median age, 13 y; median body mass index Z-score, 2.43), the median NAFLD Activity Score was 4 (interquartile range, 3-5). In multivariable regression analyses, the skeletal muscle mass index was negatively associated with hepatic steatosis after controlling for confounders (odds ratio, 0.76; 95% confidence interval, 0.62-0.93). Similarly, the appendicular muscle mass index was negatively associated with severity of hepatic steatosis severity (odds ratio, 0.69; 95% confidence interval, 0.53-0.90). In contrast, percentage body fat was not associated with hepatic steatosis. NAFLD Activity Score, lobular inflammation, ballooning scores, and fibrosis stage were not associated with measures of body composition.

CONCLUSIONS

There is an inverse association between BIA-based measures of muscle mass and severity of hepatic steatosis in children with NAFLD. BIA data could further inform clinical decision making in this context.

Association of Body Composition and Sarcopenia with NASH in Obese Patients

Obese patients often suffer from sarcopenia or sarcopenic obesity (SO) that can trigger inflammatory diseases including non-alcoholic steatohepatitis (NASH). Sarcopenia and SO can be diagnosed through measuring parameters of body composition such as skeletal muscle mass (SMM), skeletal muscle index (SMI) and fat mass (FM) obtained by bioelectrical impedance analysis (BIA). The aim of this study was to assess the relationship of body composition and NASH in patients with obesity. A total of 138 patients with obesity that underwent bariatric surgery were included in this study. BIA was used to estimate body composition. A liver biopsy was taken intraoperatively and histological assessment of NASH was performed. A total of 23 patients (17%) were classified as NASH and 65 patients (47%) met the criteria for borderline NASH. Body mass index (BMI) was significantly higher in patients with NASH compared to borderline NASH and no NASH (56.3 kg/m² vs. 51.6 kg/m² vs. 48.6 kg/m², p = 0.004). Concerning body composition, FM, but also SMM and SMI were significantly higher in patients with NASH (p-values 0.011, 0.005 and 0.006, resp.). Fat mass index (FMI) and weight-adjusted skeletal muscle index (SMI_weight) failed to reach statistical significance (p-values 0.067 and 0.661). In patients with obesity, higher FM were associated with NASH. Contrary to expectations, SMM and SMI were also higher in patients with NASH. Therefore, higher body fat, rather than sarcopenia and SO, might be decisive for development of NASH in patients with obesity.

Relationship Between Protein Intake and Sarcopenia in the Elderly with Nonalcoholic Fatty Liver Disease Based on the Fourth and Fifth Korea National Health and Nutrition Examination Survey

Background: The association between sarcopenia and protein intake has been well studied. However, limited data are available on the association between sarcopenia and protein intake in people with nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the association between protein intake and sarcopenia among elderly participants with NAFLD using the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: Data of 4179 participants (1576 men and 2603 women, age ≥60 years) who participated in the KNHANES during 2008-2011 were obtained. Sarcopenia was defined as appendicular skeletal muscle mass/wt (%) of 1 standard deviation below the gender-specific mean for healthy adults and NAFLD as liver fat score using the fatty liver prediction models. According to their daily protein intake, participants were grouped into the high protein intake group (>1.2 g/kg/day), middle protein intake group (0.8-1.2 g/kg/day), and low protein intake group (<0.8 g/kg/day). Generalized linear models and logistic regression models were used. Results: The overall prevalence of sarcopenia in participants with NAFLD was 16.53%. Compared with the highest protein intake group, the low protein intake group had a significantly higher risk of sarcopenia (adjustment odds ratio = 1.707; 95% confidence interval = 1.009-2.886). In the fully adjusted model, the highest protein intake group had significantly lower levels of insulin, total body fat, vitamin B, and fat intake, whereas muscle proportions, energy, carbohydrates, vitamin A, and vitamin C intake of high protein intake participants were significantly higher than other groups. Conclusion: The prevalence of sarcopenia and sarcopenia-related factors were significantly lower in NAFLD elderly participants with high protein intake. These results suggest that high protein intake can help prevent and manage sarcopenia in people with NAFLD.

Metabolic complications of hepatitis C virus infection

Hepatitis C virus (HCV) infection is a systemic disease that is implicated in multiple extrahepatic organ dysfunction contributing to its protean manifestations. HCV is associated with diverse extrahepatic disorders including atherosclerosis, glucose and lipid metabolic disturbances, alterations in the iron metabolic pathways, and lymphoproliferative diseases over and above the traditional liver manifestations of cirrhosis and hepatocellular carcinoma. The orchestration between HCV major proteins and the liver-muscle-adipose axis, poses a major burden on the global health of human body organs, if not adequately addressed. The close and inseparable associations between chronic HCV infection, metabolic disease, and cardiovascular disorders are specifically important considering the increasing prevalence of obesity and metabolic syndrome, and their economic burden to patients, the healthcare systems, and society. Cellular and molecular mechanisms governing the interplay of these organs and tissues in health and disease are therefore of significant interest. The coexistence of metabolic disorders and chronic hepatitis C infection also enhances the progression to liver fibrosis and hepatocellular carcinoma. The presence of metabolic disorders is believed to influence the chronicity and virulence of HCV leading to liver disease progression. This comprehensive review highlights current knowledge on the metabolic manifestations of hepatitis C and the potential pathways in which these metabolic changes can influence the natural history of the disease.

Skeletal Muscle Dysfunction in the Development and Progression of Nonalcoholic Fatty Liver Disease

The association between the pathogenesis and natural course of nonalcoholic fatty liver disease (NAFLD) and skeletal muscle dysfunction is increasingly recognized. These obesity-associated disorders originate primarily from sustained caloric excess, gradually disrupting cellular and molecular mechanisms of the adipose-muscle-liver axis resulting in end-stage tissue injury exemplified by cirrhosis and sarcopenia. These major clinical phenotypes develop through complex organ-tissue interactions from the earliest stages of NAFLD. While the role of adipose tissue expansion and remodeling is well established in the development of NAFLD, less is known about the specific interplay between skeletal muscle and the liver in this process. Here, the relationship between skeletal muscle and liver in various stages of NAFLD progression is reviewed. Current knowledge of the pathophysiology is summarized with the goal of better understanding the natural history, risk stratification, and management of NAFLD.

Harnessing Muscle-Liver Crosstalk to Treat Nonalcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) has reached epidemic proportions, affecting an estimated one-quarter of the world's adult population. Multiple organ systems have been implicated in the pathophysiology of NAFLD; however, the role of skeletal muscle has until recently been largely overlooked. A growing body of evidence places skeletal muscle-via its impact on insulin resistance and systemic inflammation-and the muscle-liver axis at the center of the NAFLD pathogenic cascade. Population-based studies suggest that sarcopenia is an effect-modifier across the NAFLD spectrum in that it is tightly linked to an increased risk of non-alcoholic fatty liver, non-alcoholic steatohepatitis (NASH), and advanced liver fibrosis, all independent of obesity and insulin resistance. Longitudinal studies suggest that increases in skeletal muscle mass over time may both reduce the incidence of NAFLD and improve preexisting NAFLD. Adverse muscle composition, comprising both low muscle volume and high muscle fat infiltration (myosteatosis), is highly prevalent in patients with NAFLD. The risk of functional disability conferred by low muscle volume in NAFLD is further exacerbated by the presence of myosteatosis, which is twice as common in NAFLD as in other chronic liver diseases. Crosstalk between muscle and liver is influenced by several factors, including obesity, physical inactivity, ectopic fat deposition, oxidative stress, and proinflammatory mediators. In this perspective review, we discuss key pathophysiological processes driving sarcopenia in NAFLD: anabolic resistance, insulin resistance, metabolic inflexibility and systemic inflammation. Interventions that modify muscle quantity (mass), muscle quality (fat), and physical function by simultaneously engaging multiple targets and pathways implicated in muscle-liver crosstalk may be required to address the multifactorial pathogenesis of NAFLD/NASH and provide effective and durable therapies.

Physiopathology of Lifestyle Interventions in Non-Alcoholic Fatty Liver Disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a major health problem, and its prevalence has increased in recent years. Diet and exercise interventions are the first-line treatment options, with weight loss via a hypocaloric diet being the most important therapeutic target in NAFLD. However, most NAFLD patients are not able to achieve such weight loss. Therefore, the requisite is the investigation of other effective therapeutic approaches. This review summarizes research on understanding complex pathophysiology underlying dietary approaches and exercise interventions with the potential to prevent and treat NAFLD.

Nonalcoholic Fatty Liver Disease and Sarcopenia: Where Do We Stand?

The link between metabolic syndrome (MetS) and sarcopenia has not been extensively studied, but it is evident that they share several common features. Crucial mechanisms involved in sarcopenia-nonalcoholic fatty liver disease (NAFLD) interplay are based on effects of insulin resistance, chronic inflammation, oxidative stress, and crosstalk between organs by secretion of cytokines (hepatokines, adipokines, and myokines). Currently, published studies confirm the association of sarcopenia with the degree of NAFLD defined by liver histology. However, prospective studies that will give us information regarding the causal effect of NAFLD and sarcopenia are still needed. Furthermore, there is a need for a patient-friendly, noninvasive, low-cost method for detection of loss of skeletal muscle mass, strength, and physical performance in the context of NAFLD. Moreover, potential treatment strategies such as physical exercise and nutritional supplementation, that are usually a part of management of sarcopenia, should also be investigated in NAFLD patients, especially given the fact that for now, we do not have a good treatment option for NAFLD. Therefore, future investigations should combine studies on NAFLD and sarcopenia in terms of physical activity and nutritional interventions such as vitamin D supplementation. This review aims to report recent evidence concerning the links between sarcopenia and NAFLD and methods to assess sarcopenia.

Contribution of sarcopenia and physical inactivity to mortality in people with non-alcoholic fatty liver disease

Background & Aims

Physical inactivity and sedentary lifestyle have contributed to the epidemic of obesity and non-alcoholic fatty liver disease (NAFLD). We assessed the association between physical activity, NAFLD, and sarcopenia, and their contributions to mortality.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 with Linked Mortality file (through 2015) was utilised. NAFLD was determined by the US Fatty Liver Index in the absence of secondary causes of liver disease. Sarcopenia was defined using appendicular lean mass divided by body mass index by the Foundation for the National Institutes of Health criteria. Activity level was determined using standard self-reports. Publicly available imputed dual-energy X-ray absorptiometry data sets were used.

Results

Of 4,611 NHANES participants (48.2% males; 72.5% White; mean age 45.9 years), NAFLD was present in 1,351 (29.3%), of whom 17.7% had sarcopenia. Of the NAFLD group, 46.3% was inactive, whilst intermediate and ideal physical activity rates were observed in 14.2% and 39.5%, respectively. Sarcopenia was significantly and inversely related to higher physical activity level, both amongst NAFLD (odds ratio [OR] = 0.45 [95% CI 0.30-0.69]) and non-NAFLD (OR = 0.51 [0.35-0.75]) groups. During a median follow-up of 13.5 years, a total of 586 subjects died, of whom 251 had NAFLD. Amongst those who died with NAFLD, 33.0% had sarcopenia and 54.3% were inactive. Compared with NAFLD without sarcopenia, NAFLD with sarcopenia was associated with a higher risk of all-cause (hazard ratio [HR] = 1.78 [1.16-2.73]), cardiac-specific (HR = 3.19 [1.17-8.74]), and cancer-specific mortality (HR = 2.12 [1.08-4.15]).

Conclusions

Inactivity is associated with presence of sarcopenia, whilst sarcopenia is associated with increased mortality amongst NAFLD patients. Sarcopenia should be a part of clinical assessment of patients with NAFLD. Treatment of NAFLD should include optimal management of sarcopenia.

Lay summary

Nonalcoholic fatty liver disease (NAFLD) and sarcopenia have similar pathophysiological profiles. Our data show that sarcopenia is associated with inactivity in subjects with NAFLD. The presence of sarcopenia in patients with NAFLD poses increased risk for all-cause and cardiac-specific mortality.

Muscle Mass Is Linked to Liver Disease Severity in Pediatric Nonalcoholic Fatty Liver Disease

OBJECTIVE

To investigate the association between muscle mass and liver disease severity in pediatric patients with non-alcoholic fatty liver disease (NAFLD).

STUDY DESIGN

This was a retrospective study of patients aged <20 years followed from 2009 to 2018. Muscle mass was estimated in all patients by measuring magnetic resonance imaging-based total psoas muscle surface area (tPMSA) and correcting for height (tPMSA index = tPMSA/height²). Two cohorts were studied, one with histological confirmation of NAFLD (n = 100) and the other with magnetic resonance imaging (MRI) evidence of hepatic steatosis (n = 236). Histology was scored using Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) criteria. MRI-measured proton density fat fraction (PDFF) and liver stiffness were collected. Demographic, clinical, and socioeconomic status (using a validated Community Deprivation Index [CDI]) were assessed as covariates. Univariate regression analyses, followed by multivariable regression analyses, were used to determine the relationships between tPMSA index and NAS, MRI-PDFF, and liver stiffness, adjusting for clinical, demographic, and CDI variables.

RESULTS

In the multivariable regression analyses, higher steatosis score was associated with a lower tPMSA index (OR, 0.73; 95% CI, 0.56-0.96) and younger age (OR, 0.84; 95% CI, 0.73-0.97). Liver PDFF was also significantly associated with the tPMSA index (P = .029), sex (P = .019), and CDI (P = .005). In contrast, liver stiffness was not associated with tPMSA in multivariable analyses.

CONCLUSIONS

tPMSA index was independently associated with both imaging and histological features of hepatic steatosis severity in children. Future studies should directly explore the presence and directionality of causative links between muscle mass and steatosis, as well as whether interventions that enhance muscle mass can reduce disease severity in children with NAFLD.

Sarcopenia Is an Independent Risk Factor for NAFLD in COPD: A Nationwide Survey (KNHANES 2008-2011)

Background

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in patients with chronic obstructive pulmonary disease (COPD) and is independently associated with cardiometabolic comorbidities and systemic inflammation. Although several factors are associated with NAFLD, the influence of sarcopenia on NAFLD has not been fully determined in patients with COPD. We explored whether sarcopenia is associated with NAFLD in a COPD population.

Methods

Data from the Korean National Health and Nutrition Examination Surveys 2008–2011 were analyzed. The subjects were defined as having NAFLD when they had a hepatic steatosis index (HSI) score >36, which is a previously validated NAFLD prediction score. Sarcopenia_BMI (=total appendicular skeletal muscle mass [kg]/body mass index [kg/m²]), sarcopenia_BW (=total appendicular skeletal muscle mass [kg]/body weight [kg] × 100), and sarcopenia_height (= total appendicular skeletal muscle mass (kg)/height² (m)) measured using dual-energy X-ray absorptiometry was used to diagnose sarcopenia.

Results

NAFLD was identified in 124 (14.6%) of 850 COPD subjects using the HSI. Multivariable logistic analyses adjusted for age, sex, hypertension, diabetes mellitus (DM), forced vital capacity (FVC), and metabolic syndrome demonstrated that sarcopenia (sarcopenia_BMI, odds ratio [OR] = 1.95; 95% confidence interval [CI], 1.11–3.46, p = 0.022; sarcopenia_BW, OR = 2.25; 95% CI, 1.30–3.92, p = 0.004) was associated with NAFLD in patients with COPD. The proportion of sarcopenia_BMI was higher in patients with a high fibrotic burden from NAFLD (Q3, Q4) than in subjects with a low fibrotic burden from NALFD (Q1, Q2) (54.8% vs 24.2%, p = 0.024). The proportion of sarcopenia_BW was also higher in patients with a high fibrotic burden from NAFLD than in patients with a low fibrotic burden from NAFLD (51.6% vs 30.6%, p = 0.029).

Conclusion

Sarcopenia was associated with an increased risk for NAFLD in patients with COPD, independent of age, sex, lung function, and metabolic factors. Sarcopenic COPD was also associated with a high fibrotic burden in NAFLD patients. Pulmonologists should be aware of possible liver comorbidities in the sarcopenic COPD phenotype.

SARCOPENIA AND SEVERITY OF NON-ALCOHOLIC FATTY LIVER DISEASE

BACKGROUND

Non-alcoholic fatty liver disease is characterized by deposition of lipids in the hepatic parenchyma exceeding 5% of liver weight in the absence of other conditions, such as viral or alcoholic hepatitis and metabolic disease. Non-alcoholic fatty liver disease is the most common form of chronic liver disease in several countries. In addition to liver complications, recent studies have shown a relation between liver fat and sarcopenia.

OBJECTIVE

Determine the association between sarcopenia and the severity of non-alcoholic hepatic steatosis diagnosed by abdominal ultrasonography.

METHODS

A clinical, cross-sectional study was conducted with a sample of male and female adults (18 to 70 years of age) submitted to ultrasonography for the investigation of non-alcoholic hepatic steatosis. Evaluations were also performed for the determination of upper and lower limb muscle strength. Data analysis was performed with the aid of the SPSS 22.0 program and involved ANCOVA and the Bonferroni post hoc test, with P-value <0.05 considered indicative of statistical significance.

RESULTS

One hundred two patients were submitted to abdominal ultrasonography, 57.8% of whom presented some degree of non-alcoholic hepatic steatosis. The presence and degree of fatty liver infiltration were significantly associated with the sarcopenic index, determined by the ratio between upper and lower limb strength and BMI (P=0.009 and post-test P=0.028 for upper limbs; P=0.006 and post-test P=0.013 for lower limbs).

CONCLUSION

In the present study, an association was found between the sarcopenic index and non-alcoholic hepatic steatosis, with an inversely proportional relation between this index and the severity of fatty infiltration. This finding offers further evidence of the metabolic interaction of the liver, adipose tissue and muscle.

The Association between Nonalcoholic Fatty Liver Disease and CT-Measured Skeletal Muscle Mass

A relationship between nonalcoholic fatty liver disease (NAFLD) and sarcopenia has been suggested. The aim of this study was to evaluate the association between NAFLD and skeletal muscle mass measured by computed tomography (CT). The clinical records of individuals visiting our center for a routine health check-up who underwent abdominal ultrasonography and abdominal CT scanning were retrospectively reviewed. Sarcopenia was diagnosed according to body mass index (BMI)-adjusted skeletal muscle mass, which was measured by CT (CT-measured skeletal muscle index (SMI_CT)). Of the 1828 subjects (1121 males; mean age 54.9 ± 9.5 years), 487 (26.6%) were obese (BMI ≥ 25 kg/m²), and 454 (24.8%) had low muscle mass. Sarcopenic subjects had a significantly higher prevalence of NAFLD than nonsarcopenic subjects, regardless of obesity (35.9% vs. 26.8%, p = 0.004 in the nonobese group; 76.6% vs. 63.0%, p = 0.003 in the obese group). Sarcopenia was significantly associated with the risk of NAFLD (adjusted odds ratio (OR) (95% confidence interval (CI)), 1.51 (1.15–1.99)), and the risk of NAFLD increased with increasing severity of sarcopenia (adjusted OR (95% CI), 1.45 (1.09–1.92) vs. 2.51 (1.16–5.56), mild vs. severe sarcopenia, respectively). When the risk of NAFLD was analyzed according to the SMI_CT quartiles, the adjusted OR and 95% CI for the lowest muscle mass quartile compared to the highest were 1.78 (1.17–2.72) in males and 2.39 (1.13–5.37) in females. Low skeletal muscle mass, which was precisely measured by CT, is independently associated with NAFLD, suggesting that sarcopenia is a risk factor for NAFLD.