Clinical relevance of skeletal muscle abnormalities in patients with cirrhosis

Mid-arm muscle circumference cutoff points in patients with cirrhosis: Low muscle mass related to malnutrition predicts mortality

OBJECTIVES

Muscle loss is one of the phenotypic criteria of malnutrition, is highly prevalent in patients with cirrhosis, and is associated with adverse outcomes. Mid-arm muscle circumference (MAMC) estimates the skeletal muscle mass and is especially helpful in cases of fluid overload. This study aimed to propose MAMC cutoff points for patients with cirrhosis and demonstrate its association with 1-year mortality.

METHODS

This is an analysis of cohort databases from five reference centers in Brazil that included inpatients and outpatients with cirrhosis aged ≥18 y. The nutritional variables obtained were the MAMC (n = 1075) and the subjective global assessment (n = 629). We established the MAMC cutoff points stratified by sex based on the subjective global assessment as a reference standard for malnutrition diagnosis, considering the sensitivity, specificity, and Youden index. An adjusted Cox regression model was used to test the association of MAMC cutoff points and 1-year mortality.

RESULTS

We included 1075 patients with cirrhosis, with a mean age of 54.8 ± 11.3 y; 70.4% (n = 757) male. Most patients had alcoholic cirrhosis (47.1%, n = 506) and were classified as Child-Pugh B (44.7%, n = 480). The MAMC cutoff points for moderate and severe depletion were ≤21.5 cm and ≤24.2 cm; ≤20.9 cm and ≤22.9 cm for women and men, respectively. According to these cutoff points, 13.8% (n = 148) and 35.1% (n = 377) of the patients had moderate or severe MAMC depletion, respectively. The 1-year mortality rate was 17.3% (n = 186). In the multivariate analysis adjusted for sex, age, MELD-Na, and Child-Pugh scores, a severe depletion in MAMC was an independent increased risk factor for 1-year mortality (HR: 1.71, 95% CI: 1.24-2.35, P < 0.001). Each increase of 1 cm in MAMC values was associated with an 11% reduction in 1-year mortality risk (HR: 0.89, 95% CI: 0.85-0.94, P < 0.001).

CONCLUSIONS

Low MAMC classified according to the new cutoff points predicts mortality risk in patients with cirrhosis and could be used in clinical practice.

Skeletal muscle alterations indicate poor prognosis in cirrhotic patients: a multicenter cohort study in China

INTRODUCTION

We aimed to determine the diagnostic criteria of myosteatosis in a Chinese population and investigate the effect of skeletal muscle abnormalities on the outcomes of cirrhotic patients.

METHODS

Totally 911 volunteers were recruited to determine the diagnostic criteria and impact factors of myosteatosis, and 480 cirrhotic patients were enrolled to verify the value of muscle alterations for prognosis prediction and establish new noninvasive prognostic strategies.

RESULTS

Multivariate analysis showed age, sex, weight, waist circumference, and biceps circumference had a remarkable influence on the L3 skeletal muscle density (L3-SMD). Based on the cut-off of a mean - 1.28 × SD among adults aged < 60 years, the diagnostic criteria for myosteatosis was L3-SMD < 38.93 Hu in males and L3-SMD < 32.82 Hu in females. Myosteatosis rather than sarcopenia has a close correlation with portal hypertension. The concurrence of sarcopenia and myosteatosis not only is associated with poor liver function but also evidently reduced the overall and liver transplantation-free survival of cirrhotic patients (p < 0.001). According to the stepwise Cox regression hazard model analysis, we established nomograms including TBil, albumin, history of HE, ascites grade, sarcopenia, and myosteatosis for easily determining survival probabilities in cirrhotic patients. The AUC is 0.874 (95% CI 0.800-0.949) for 6-month survival, 0.831 (95% CI 0.764-0.898) for 1-year survival, and 0.813 (95% CI 0.756-0.871) for 2-year survival prediction, respectively.

CONCLUSIONS

This study provides evidence of the significant correlation between skeletal muscle alterations and poor outcomes of cirrhosis, and establishes valid and convenient nomograms incorporating musculoskeletal disorders for the prognostic prediction of liver cirrhosis. Further large-scale prospective studies are necessary to verify the value of the nomograms.

Prognostic Effect of Sarcopenia in Hepatocellular Carcinoma Patients Targeted with Interventional Therapy Combined with Immunotherapy and Targeted Therapy

Objective

To investigated the association between sarcopenia and the prognosis and adverse events of hepatocellular carcinoma (HCC) patients undergoing interventional therapy combined with immunotherapy and targeted therapy.

Methods

Between January 2019 and December 2022, patients with unresectable HCC who received interventional therapy combined with immunotherapy and targeted therapy were included in this study. Total skeletal muscle area at the L3 level was normalized for height in m2 as the skeletal muscle index (SMI). All patients were divided into low and high SMI group according to the median SMI.

Results

Ninety-six consecutive patients were included eventually, with 49 patients in the high-SMI group and 47 patients in the low-SMI group. In the low-SMI group, the median overall survival (OS) was 459.00 days (95% CI, 334.76-583.24 days), and the 3-, 6-, and 12-month OS rates were 100%, 89.4% and 68.1%, respectively. In the high-SMI group, the median OS was not reached, and the 3-, 6-, and 12-month OS rates were 100%, 98% and 79.5%, respectively (p<0.05). SMI and Barcelona Clinic Liver Cancer (BCLC) C stage were independent prognostic factors for OS (p<0.05). In the low-SMI group, 26 patients had treatment-related adverse events (TRAEs), resulting in dose adjustment or treatment suspension for 10 patients. In the high-SMI group, 33 patients had TRAEs, and 18 patients received dose adjustment or treatment suspension; the between-group difference was nonsignificant (p>0.05).

Conclusion

SMI is associated with the prognosis of HCC patients receiving interventional therapy combined with immunotherapy and targeted therapy, and sarcopenia is an independent risk factor for OS. However, sarcopenia does not seem to predict the occurrence of adverse events.

Transjugular Intrahepatic Portosystemic Shunt Placement: Effects on Nutritional Status in Cirrhotic Patients

Malnutrition is a tangible complication of cirrhosis with portal hypertension with a prevalence of up to 50%. In particular, sarcopenia and myosteatosis, defined as the alteration in muscle quantity and quality, have a negative impact on the main complications of liver disease and are associated with higher mortality in patients with cirrhosis. Recently, alterations in adipose tissue have also been described in cirrhotic patients and they seem to influence the course of liver disease. Several pieces of evidence indicate that a transjugular intrahepatic portosystemic shunt (TIPS), placed for the treatment of refractory portal hypertension, can lead to a modification of body composition consisting in the improvement of the skeletal muscle index, myosteatosis, and an increase in subcutaneous fat. These modifications of the nutritional status, even more pronounced in sarcopenic patients before TIPS, have been associated with an amelioration of cognitive impairment after TIPS as well as with an increase in the survival rate. The aim of this paper is to provide an overview of the effects of TIPS placement on nutritional status in cirrhosis focusing on its pathophysiological mechanisms and its relationship with liver-related outcomes.

AI-based CT Body Composition Identifies Myosteatosis as Key Mortality Predictor in Asymptomatic Adults

Background Body composition data have been limited to adults with disease or older age. The prognostic impact in otherwise asymptomatic adults is unclear. Purpose To use artificial intelligence-based body composition metrics from routine abdominal CT scans in asymptomatic adults to clarify the association between obesity, liver steatosis, myopenia, and myosteatosis and the risk of mortality. Materials and Methods In this retrospective single-center study, consecutive adult outpatients undergoing routine colorectal cancer screening from April 2004 to December 2016 were included. Using a U-Net algorithm, the following body composition metrics were extracted from low-dose, noncontrast, supine multidetector abdominal CT scans: total muscle area, muscle density, subcutaneous and visceral fat area, and volumetric liver density. Abnormal body composition was defined by the presence of liver steatosis, obesity, muscle fatty infiltration (myosteatosis), and/or low muscle mass (myopenia). The incidence of death and major adverse cardiovascular events were recorded during a median follow-up of 8.8 years. Multivariable analyses were performed accounting for age, sex, smoking status, myosteatosis, liver steatosis, myopenia, type 2 diabetes, obesity, visceral fat, and history of cardiovascular events. Results Overall, 8982 consecutive outpatients (mean age, 57 years ± 8 [SD]; 5008 female, 3974 male) were included. Abnormal body composition was found in 86% (434 of 507) of patients who died during follow-up. Myosteatosis was found in 278 of 507 patients (55%) who died (15.5% absolute risk at 10 years). Myosteatosis, obesity, liver steatosis, and myopenia were associated with increased mortality risk (hazard ratio [HR]: 4.33 [95% CI: 3.63, 5.16], 1.27 [95% CI: 1.06, 1.53], 1.86 [95% CI: 1.56, 2.21], and 1.75 [95% CI: 1.43, 2.14], respectively). In 8303 patients (excluding 679 patients without complete data), after multivariable adjustment, myosteatosis remained associated with increased mortality risk (HR, 1.89 [95% CI: 1.52, 2.35]; P < .001). Conclusion Artificial intelligence-based profiling of body composition from routine abdominal CT scans identified myosteatosis as a key predictor of mortality risk in asymptomatic adults. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Tong and Magudia in this issue.

Skeletal muscle mass in patients with end-stage liver disease: Not only muscle size but especially muscle quality matters in relation to physical fitness

BACKGROUND

Physical fitness is an important modifiable factor related to quality of life. Sarcopenia and myosteatosis are associated with morbidity and mortality in patients with end-stage liver disease (ESLD). However, their relationship with physical fitness has not been established yet. Therefore, the main purpose of this study was to investigate the association between both low skeletal muscle index (SMI) and myosteatosis with physical fitness in patients with ESLD.

METHODS

In this retrospective cross-sectional cohort study, a cohort of patients with ESLD who were evaluated for liver transplantation (LT) was included. Physical fitness was reflected by cardiorespiratory fitness (CRF) and skeletal muscle strength, as measured by the 6-min walking distance (6MWD) and handgrip strength (HGS), respectively. Both were included in routine LT evaluation. Skeletal Muscle Index (SMI) and Muscle Radiation Attenuation (MRA) were evaluated based on the routine abdominal computed tomography. Linear and logistic regression analyses were performed.

RESULTS

Out of the 130 patients 94 (72%) were male, mean age was 56 ± 11 years. Myosteatosis was significantly associated with low 6MWD as percentage of predicted (β = -12.815 (CI -24.608 to -1.022, p-value 0.034)) as well as with low absolute 6MWD (<250 m) (OR 3.405 (CI 1.134-10.220, p-value 0.029)). No association was found between SMI and/or myosteatosis with HGS, or between SMI and 6MWD.

CONCLUSION

In contrast to SMI, myosteatosis is associated with low CRF. Neither low SMI nor myosteatosis was associated with skeletal muscle strength. Therefore physical exercise training might be especially beneficial for LT candidates with myosteatosis.

Contributory roles of sarcopenia and myosteatosis in development of overt hepatic encephalopathy and mortality after transjugular intrahepatic portosystemic shunt

BACKGROUND

Skeletal muscle abnormalities, such as muscle mass depletion (sarcopenia) and fatty infiltration of the muscle (myosteatosis), are frequent complications in cirrhotic patients scheduled for transjugular intrahepatic portosystemic shunt (TIPS).

AIM

To investigate the association and predictive value of sarcopenia and myosteatosis for overt hepatic encephalopathy (HE) and mortality after TIPS.

METHODS

The records of cirrhotic patients who underwent the TIPS procedure at our hospital between January 2020 and June 2021 were retrospectively retrieved. The transversal psoas muscle thickness (TPMT) and psoas muscle attenuation (PMA) measured from the unenhanced abdominal computed tomography (CT) at the level of the third lumbar vertebrae were used to analyze the sarcopenia and myosteatosis, respectively. The area under curve (AUC) was used to evaluate the discriminative power of TPMT, PMA, and relevant clinical parameters. Fur-thermore, log-rank test was performed to compare the incidence of overt HE and survival between the different groups, and the association of risk factors with overt HE and mortality was analyzed using Cox proportional hazards regression models.

RESULTS

A total of 108 patients were collected. Among these patients, 45.4% of patients developed overt HE after TIPS treatment. Furthermore, 32.4% and 28.7% of these patients were identified to have myosteatosis and sarcopenia, respectively. Myosteatosis (51.0% vs 16.9%, P < 0.001) and sarcopenia (40.8 vs 18.6%, P = 0.011) were found to be more frequent in patients with overt HE, when compared to patients without overt HE. The receiver operating characteristics analysis indicated that the predictive power of TPMT and PMA in overt HE (AUC = 0.713 and 0.778, respectively) was higher when compared to the neutrophil lymphocyte ratio (AUC = 0.636). The cumulative incidence of overt HE was the highest in patients with concomitant sarcopenia and myosteatosis, followed by patients with myosteatosis or sarcopenia, while this was the lowest in patients without sarcopenia and myosteatosis. In addition, sarcopenia and myosteatosis were inde-pendently associated with overt HE and mortality after adjusting for confounding factors in post-TIPS patients.

CONCLUSION

CT-based estimations for sarcopenia and myosteatosis can be used as reliable predictors for the risk of developing overt HE and mortality in cirrhotic patients after TIPS.

Muscle abnormalities in patients with liver cirrhosis and its effect on muscle function

OBJECTIVES

The progression of chronic liver disease is associated with metabolic alterations that compromise the patient's body composition and physical function. Muscle wasting often occurs with pathologic fat accumulation in the muscle (myosteatosis). Unfavorable changes in body composition frequently arise in conjunction with a decrease in muscle strength. These conditions are associated with worse prognoses. The aim of this study was to explore the associations between computed tomography (CT)-derived measures of muscle mass and muscle radiodensity (myosteatosis) and its correlation with muscle strength in patients with advanced chronic liver disease.

METHODS

This cross-sectional study was conducted between July 2016 and July 2017. CT images at the third lumbar vertebra level (L3) were analyzed, and skeletal muscle index (SMI) and skeletal muscle radiodensity (SMD) were defined. Handgrip strength (HGS) was assessed by dynamometry. Correlations between CT-assessed body composition and HGS were tested. Multivariable linear regression was used to determine the factors associated with HGS.

RESULTS

We evaluated 118 patients with cirrhosis, of whom 64.4% were men. Of those evaluated, the mean age was 57.5 ± 8.5 y. Both SMI and SMD showed a positive correlation with muscle strength (r = 0.46 and 0.25, respectively); and age and Model for End-Stage Liver Disease (MELD)score showed the highest negative correlations (r = -0.37 and -0.34, respectively). In multivariable analyses, the presence of comorbidities (≥1), MELD score, and SMI were significantly associated with HGS.

CONCLUSIONS

Low muscle mass and clinical characteristics of disease severity may adversely affect muscle strength in patients with liver cirrhosis.

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.

Biomedical role of L-carnitine in several organ systems, cellular tissues, and COVID-19

Carnitine is a conditionally necessary vitamin that aids in energy creation and fatty acid metabolism. Its bioavailability is higher in vegetarians than in meat-eaters. Deficits in carnitine transporters occur because of genetic mutations or in conjunction with other illnesses. Carnitine shortage can arise in health issues and diseases-including hypoglycaemia, heart disease, starvation, cirrhosis, and ageing-because of abnormalities in carnitine control. The physiologically active form of L-carnitine supports immunological function in diabetic patients. Carnitine has been demonstrated to be effective in the treatment of Alzheimer's disease, several painful neuropathies, and other conditions. It has been used as a dietary supplement for the treatment of heart disease, and it also aids in the treatment of obesity and reduces blood glucose levels. Therefore, L-carnitine shows the potential to eliminate the influences of fatigue in COVID-19, and its consumption is recommended in future clinical trials to estimate its efficacy and safety. This review focused on carnitine and its effect on tissues, covering the biosynthesis, metabolism, bioavailability, biological actions, and its effects on various body systems and COVID-19.

Impact of L-ornithine L-aspartate on non-alcoholic steatohepatitis-associated hyperammonemia and muscle alterations

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease in the world. Progression toward non-alcoholic steatohepatitis (NASH) is associated with alterations of skeletal muscle. One plausible mechanism for altered muscle compartment in liver disease is changes in ammonia metabolism. In the present study, we explored the hypothesis that NASH-associated hyperammonemia drives muscle changes as well as liver disease progression.

MATERIALS AND METHODS

In Alms1-mutant mice (foz/foz) fed a 60% fat diet (HFD) for 12 weeks; we investigated hepatic and muscular ammonia detoxification efficiency. We then tested the effect of an 8 week-long supplementation with L-ornithine L-aspartate (LOLA), a known ammonia-lowering treatment, given after either 4 or 12 weeks of HFD for a preventive or a curative intervention, respectively. We monitored body composition, liver and muscle state by micro computed tomography (micro-CT) as well as muscle strength by four-limb grip test.

RESULTS

According to previous studies, 12 weeks of HFD induced NASH in all foz/foz mice. Increase of hepatic ammonia production and alterations of urea cycle efficiency were observed, leading to hyperammonemia. Concomitantly mice developed marked myosteatosis. First signs of myopenia occurred after 20 weeks of diet. Early LOLA treatment given during NASH development, but not its administration in a curative regimen, efficiently prevented myosteatosis and muscle quality, but barely impacted liver disease or, surprisingly, ammonia detoxification.

CONCLUSION

Our study confirms the perturbation of hepatic ammonia detoxification pathways in NASH. Results from the interventional experiments suggest a direct beneficial impact of LOLA on skeletal muscle during NASH development, though it does not improve ammonia metabolism or liver disease.

An improved method to assess skeletal muscle mass in patients with liver cirrhosis based on computed tomography images

AIM

Conventionally, the skeletal muscle area with computed tomography (CT) attenuation ranging from -29 to +150 Hounsfield unit (HU) divided by height squared (the conventional skeletal muscle index [SMI]) was used as an index of skeletal muscle mass. However, it includes fat-infiltrated skeletal muscle, which is known to have poor function. This study aims to determine whether the low-fat SMI, which uses skeletal muscle mass with CT attenuation ranging from +30 to +150 HU, or conventional SMI appropriately reflects the function of skeletal muscle.

METHODS

We retrospectively analyzed 120 patients with cirrhosis whose handgrip strength was measured. Among them, 48 patients underwent a physical performance assessment such as liver frailty index (LFI) and short physical performance battery (SPPB), and 80 underwent quality of life (QOL) assessment. The relationships between each SMI and handgrip strength, LFI, SPPB, and QOL were evaluated.

RESULTS

Low-fat SMI was significantly correlated with handgrip strength (males, R = 0.393, p = 0.002; females, R = 0.423, p < 0.001) and LFI (males, R = -0.535, p = 0.035; females, R = -0.368, p = 0.039), whereas conventional SMI was not. When using low-fat SMI, patients with low skeletal muscle mass had significantly low handgrip strength, LFI, SPPB, and physical and social-related QOL score than those without. By contrast, no significant differences were found for any items when using conventional SMI.

CONCLUSIONS

Low-fat SMI is a good index of skeletal muscle mass that appropriately reflects skeletal muscle function.

What Is the Role of Body Composition Assessment in HCC Management?

In the last decade, body composition (BC) assessment has emerged as an innovative tool that can offer valuable data concerning nutritional status in addition to the information provided by the classical parameters (i.e., body mass index, albumin). Furthermore, published data have revealed that different types of body composition are associated with different outcomes. For example, abnormalities of skeletal muscle, a common finding in cirrhotic and oncologic patients, are associated with poor outcome (i.e., high morbidity and high mortality). The disposition (visceral/subcutaneous adipose tissue) and radiodensity of adipose tissue proved to also be determinant factors for HCC outcome. Despite all the advantages, BC assessment is not part of the standard pre-therapeutic workup. The main reasons are the high heterogeneity of data, the paucity of prospective studies, the lack of a standard assessment method, and the interpopulation variation of BC. This paper aims to review the available evidence regarding the role of BC as a prognostic tool in the HCC population undergoing various therapies.

Impact of sarcopenia on outcomes of patients undergoing liver resection for hepatocellular carcinoma

BACKGROUND

Previous studies have indicated that sarcopenia is associated with poor post-operative outcomes in liver cancer patients, but the studies are limited by confounding from mixed diseases, retrospective data, and non-standardized measurement methods. At present, there is no research with both muscle mass and strength as predictors for hepatocellular carcinoma (HCC) outcomes. We studied the impact of sarcopenia on post-operative outcomes in HCC patients in a cohort study designed according to the European Working Group on Sarcopenia in Older People standards.

METHODS

A total of 781 consecutive patients admitted to our centre were registered from May 2020 to August 2021. All participants submitted questionnaires and underwent handgrip strength, chair stand test, physical performance, and computed tomographic evaluation. Then, they were divided into three groups according to muscle mass and strength: Group A (reduced muscle mass and strength), Group B (reduced muscle strength or reduced muscle mass), and Group C (normal muscle mass and strength). The baseline data and post-operative outcomes were compared and analysed. The primary outcome variable in this study was the presence of a major post-operative complication, and the secondary outcome was the 90-day re-admission rate.

RESULTS

A total of 155 patients [median age, 60.00 (IQR, 51.00-66.00) years; 20 females (12.90%)] were included after strict exclusion. The mean (SD) BMI was 23.37 ± 0.23 kg/m² . The mean (SD) SMI of all participants was 47.05 ± 0.79 cm² /m² , and the mean (SD) handgrip strength was 32.84 ± 0.69 kg. Among them, 77 (49.68%) patients underwent laparoscopic hepatectomy, and 73 (47.10%) patients received major hepatectomy. Regarding the post-operative results, Group A had a higher rate of major complications [40.91% (9 of 22) vs. 11.94% (8 of 67) in Group B and 6.06 (4 of 66) in Group C; P = 0.001], higher rate of blood transfusion (77.27% vs. 46.27% in Group B and 42.42% in Group C; P = 0.015), higher hospitalization expenses (P = 0.001), and longer hospital stay (P < 0.001). There was no difference in 90-day re-admission rates among the three groups. Sarcopenia (hazard ratio, 10.735; 95% CI, 2.547-45.244; P = 0.001) and open surgery (hazard ratio, 4.528; 95% CI, 1.425-14.387; P = 0.010) were independent risk factors associated with major complications.

CONCLUSIONS

Sarcopenia is associated with adverse outcomes after liver resection for HCC. It should be evaluated upon admission to classify high-risk patients and reduce the risk of major complications.

Skeletal Muscle Pathological Fat Infiltration (Myosteatosis) Is Associated with Higher Mortality in Patients with Cirrhosis

Myosteatosis (pathological fat accumulation in muscle) is defined by lower mean skeletal muscle radiodensity in CT. We aimed to determine the optimal cut-offs for myosteatosis in a cohort of 855 patients with cirrhosis. CT images were used to determine the skeletal muscle radiodensity expressed as Hounsfield Unit (HU). Patients with muscle radiodensity values below the lowest tertile were considered to have myosteatosis. Competing-risk analysis was performed to determine associations between muscle radiodensity and pre-transplant mortality. Muscle radiodensity less than 33 and 28 HU in males and females, respectively, were used as cut-offs to identify myosteatosis. In the univariate analysis, cirrhosis etiology, MELD score, refractory ascites, variceal bleeding, hepatic encephalopathy, sarcopenia and myosteatosis were predictors of mortality. Myosteatosis association with mortality remained significant after adjusting for confounding factors (sHR 1.47, 95% CI 1.17−1.84, p = 0.001). Patients with concurrent presence of myosteatosis and sarcopenia constituted 17% of the patient population. The cumulative incidence of mortality was the highest in patients with concomitant sarcopenia and myosteatosis (sHR 2.22, 95% CI 1.64−3.00, p < 0.001). In conclusion, myosteatosis is common in patients with cirrhosis and is associated with increased mortality. The concomitant presence of myosteatosis and sarcopenia is associated with worse outcomes.

Myosteatosis in Cirrhosis: A Review of Diagnosis, Pathophysiological Mechanisms and Potential Interventions

Myosteatosis, or pathological excess fat accumulation in muscle, has been widely defined as a lower mean skeletal muscle radiodensity on computed tomography (CT). It is reported in more than half of patients with cirrhosis, and preliminary studies have shown a possible association with reduced survival and increased risk of portal hypertension complications. Despite the clinical implications in cirrhosis, a standardized definition for myosteatosis has not yet been established. Currently, little data exist on the mechanisms by which excess lipid accumulates within the muscle in individuals with cirrhosis. Hyperammonemia may play an important role in the pathophysiology of myosteatosis in this setting. Insulin resistance, impaired mitochondrial oxidative phosphorylation, diminished lipid oxidation in muscle and age-related differentiation of muscle stem cells into adipocytes have been also been suggested as potential mechanisms contributing to myosteatosis. The metabolic consequence of ammonia-lowering treatments and omega-3 polyunsaturated fatty acids in reversing myosteatosis in cirrhosis remains uncertain. Factors including the population of interest, design and sample size, single/combined treatment, dosing and duration of treatment are important considerations for future trials aiming to prevent or treat myosteatosis in individuals with cirrhosis.

Sarcopenia in Hepatocellular Carcinoma: Pathogenesis and Management

BACKGROUND

Sarcopenia is almost constantly observed in patients with cirrhosis and hepatocellular carcinoma.

SUMMARY

Chronic liver disease represents a unique pathophysiological scenario in which sarcopenia develops and all factors involved in the pathogenesis should be taken into account for an appropriate management of the disease. No properly designed intervention studies on this topic are available and, thus, no effective strategies have been developed for clinical practice. Apart from any targeted intervention, treatment and optimization of liver disease is crucial. Key Messages: In patients with cirrhosis and hepatocellular carcinoma, nutritional support to maintain and restore nutrition status, a targeted use of branched-chain amino acids and a guided physical exercise, should all be an integral part of the multidimensional assessment and tailored interventions.

Defining reference values for low skeletal muscle index at the L3 vertebra level based on computed tomography in healthy adults: A multicentre study

BACKGROUND & AIMS

Skeletal muscle mass loss is an important aspect of malnutrition and is closely related to adverse clinical outcomes. Computed tomography (CT) is the gold standard for analysing muscle mass, and the skeletal muscle index at the third lumbar vertebra (L3-SMI), measured using CT, is an important indicator to evaluate total skeletal tissue. The aims of this study were to establish reference values for low L3-SMI in Northern China, and to investigate the correlation between L3-SMI and age, and the correlation between L3-SMI and body mass index (BMI).

METHODS

This was a multicentre, retrospective, cross-sectional study. A search of abdominal CT imaging reports, using specific keywords, was conducted in four representative cities in northern China, from January 2016 to March 2021. Transverse CT images at the level of the third lumbar vertebra (L3) were identified, exported from the Radiology Information System, and measured using the analysis software SliceOmatic. Statistical analyses were performed using SPSS 24.0, and significance level was set at p < 0.05. Mean, standard deviations (SD) and percentiles (p5, p10, p25, p50, p75, p90, p95) were used to describe the distribution of L3-SMI in the study population. Low skeletal muscle index was defined as a 5% percentile, or two standard deviations below the mean value of younger healthy individuals (age 20-39 years).

RESULTS

The study included 1787 healthy individuals, with a median age of 45 (25) years (range 20-88 years), and a median BMI of 23.1 (4.1) kg/m² (range 18.5-38.7 kg/m²). Among them, 700 healthy individuals (39.1%) were aged 20-39 years. L3-SMI had a negative linear correlation with age, and a positive linear correlation with BMI. The L3-SMI reference values used to define low skeletal muscle mass loss in the Northern Chinese population, using the 5% percentile, were 40.2 cm²/m² in men, and 31.6 cm²/m² in women. Using the mean minus two standard deviations protocol, the reference values were 37.9 cm²/m² and 28.6 cm²/m² in men and women, respectively.

CONCLUSIONS

This study analysed the human body composition of 1787 healthy people in four cities in northern China, using CT, and established diagnostic thresholds of skeletal muscle mass depletion based on 700 younger healthy adults, using the 5% percentile and mean-2SD methods. These reference values can be used to diagnose malnutrition in patients and may aide clinicians in predicting prognosis and improving nutritional therapy. Further research is warranted to determine the prognostic role of reference values against clinical outcomes in different disease populations.

Muscular abnormalities in liver cirrhosis

Sarcopenia is becoming a well-established player in evaluating patients with chronic liver disease. Data regarding its clinical significance and consequences in the course of liver disease have been growing; many of the data support the idea that it impacts decompensation event frequency, prolonged hospitalization, and mortality, as well as providing the possibility to better prioritize patients on lists awaiting liver transplantation. When assessing the whole clinical scope of the field, which includes malnutrition and frailty, as well as the complete spectrum of muscle mass, strength, and function, it becomes clear that a well-founded approach in everyday clinical practice is essential. In this respect, this article attempts to unveil the most recently published data regarding possible methods and modalities that could be used to diagnose sarcopenia as early as possible, along with the required accuracy and reliability. From the most important field discoveries to data that need further clarification, the merits and weaknesses of the very diverse existing evaluation methods are presented. Finally, a critical overview is given, in an attempt to discern study lines of importance from those that could pose further ambiguity for the theme. The author also poses relevant questions that remain unanswered but are of clinical importance in the field.

A dynamic association between myosteatosis and liver stiffness: Results from a prospective interventional study in obese patients

Background & Aims

Retrospective cross-sectional studies linked sarcopenia and myosteatosis with metabolic dysfunction-associated fatty liver disease (MAFLD). Here, we wanted to clarify the dynamic relationship between sarcopenia, myosteatosis, and MAFLD.

Methods

A cohort of 48 obese patients was randomised for a dietary intervention consisting of 16 g/day of inulin (prebiotic) or maltodextrin (placebo) supplementation. Before and after the intervention, we evaluated liver steatosis and stiffness with transient elastography (TE); we assessed skeletal muscle index (SMI) and skeletal muscle fat index (SMFI) (a surrogate for absolute fat content in muscle) using computed tomography (CT) and bioelectrical impedance analysis (BIA).

Results

At baseline, sarcopenia was uncommon in patients with MAFLD (4/48, 8.3%). SMFI was higher in patients with high liver stiffness than in those with low liver stiffness (640.6 ± 114.3 cm²/ Hounsfield unit [HU] vs. 507.9 ± 103.0 cm²/HU, p = 0.001). In multivariate analysis, SMFI was robustly associated with liver stiffness even when adjusted for multiple confounders (binary logistic regression, p <0.05). After intervention, patients with inulin supplementation lost weight, but this was not associated with a decrease in liver stiffness. Remarkably, upon intervention (being inulin or maltodextrin), patients who lowered their SMFI, but not those who increased SMI, had a 12.7% decrease in liver stiffness (before = 6.36 ± 2.15 vs. after = 5.55 ± 1.97 kPa, p = 0.04).

Conclusions

Myosteatosis, but not sarcopenia, is strongly and independently associated with liver stiffness in obese patients with MAFLD. After intervention, patients in which the degree of myosteatosis decreased reduced their liver stiffness, irrespective of body weight loss or prebiotic treatment. The potential contribution of myosteatosis to liver disease progression should be investigated.

Clinical Trials registration number

NCT03852069.

Lay summary

The fat content in skeletal muscles (or myosteatosis) is strongly associated with liver stiffness in obese patients with MAFLD. After a dietary intervention, patients in which the degree of myosteatosis decreased also reduced their liver stiffness. The potential contribution of myosteatosis to liver disease progression should be investigated.

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Low-radiation CT scan enables muscle evaluation (quantity and composition).

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Muscle mass is not low in patients with MAFLD and high liver stiffness.

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In contrast, myosteatosis is strongly associated with liver stiffness.

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Lower myosteatosis after dietary intervention is associated with improved MAFLD.

Myosteatosis rather than sarcopenia associates with non-alcoholic steatohepatitis in non-alcoholic fatty liver disease preclinical models

BACKGROUND

Non-alcoholic fatty liver (NAFL) disease (NAFLD) is the most common chronic liver disease in the world. While most subjects have 'inert' NAFL, a subset will progress to non-alcoholic steatohepatitis (NASH) and its life-threatening complications. A substantial body of literature supports that a low muscle mass, low strength, and/or muscle fatty infiltration (myosteatosis) are associated with NAFLD severity. Here, we evaluated the muscle compartment in NASH preclinical models to decipher the kinetics of muscle alterations in relation with liver disease progression.

METHODS

We developed and validated a micro-computed tomography-based methodology to prospectively study skeletal muscle mass and density in muscle and liver (i.e. reflecting fatty infiltration) in a high-throughput and non-invasive manner in three preclinical NAFLD/NASH rodent models: fat aussie (FOZ) mice fed a high-fat diet (FOZ HF), wild-type (WT) mice fed a high-fat high-fructose diet (WT HFF), and WT mice fed a high-fat diet (WT HF). We compared them with WT mice fed a normal diet (WT ND) used as controls.

RESULTS

-FOZ HF with fibrosing NASH had sarcopenia characterized by a reduced muscle strength when compared with WT HF and WT HFF with early NASH and WT ND controls (165.2 ± 5.2 g vs. 237.4 ± 11.7 g, 256 ± 5.7 g, and 242.9 ± 9.3 g, respectively, P 60; 0.001). Muscle mass or strength was not lower in FOZ HF, WT HF, and WT HFF with early NASH than in controls. Myosteatosis was present in FOZ HF with fibrosing NASH, but also in FOZ HF, WT HF, and WT HFF with early NASH (muscle density = 0.50 ± 0.02, 0.62 ± 0.02, 0.70 ± 0.05, and 0.75 ± 0.03, respectively, with P 60; 0.001 when compared with respective controls). Myosteatosis degree was strongly correlated with NAFLD activity score (r = -0.87, n = 67, P 60; 0.001). In multivariate analysis, the association between myosteatosis and NASH was independent from homeostatic model assessment of insulin resistance and visceral fat area (P 60; 0.05). Myosteatosis degree powerfully discriminated NASH from benign NAFL and normal liver (area under the receiver operating characteristic = 0.96, n = 67, P 60; 0.001).

CONCLUSIONS

Taken together, our data support that there is no sarcopenia in obese mice with early NASH. In contrast, the severity of myosteatosis reflects on hepatocellular damage and inflammation during early NASH development. This observation prompts us to exploit myosteatosis as a novel non-invasive marker of NASH.

A Sex-Stratified Prognostic Nomogram Incorporating Body Compositions for Long-Term Mortality in Cirrhosis

BACKGROUND

Alterations in body compositions are related to poor outcomes and the presence of complications in cirrhosis. However, no predictive tools combining all these anthropometric parameters are applicable in the clinical setting. We aimed to clarify the potential utility of body compositions and develop a nomogram incorporating any independent factor for prognosticating long-term mortality in cirrhosis.

METHODS

A total of 414 patients were randomized into primary (n = 274) and validation (n = 140) cohorts. X-tile was performed to identify optimal cut points for stratifying participants. Multivariate Cox regression was performed, and nomogram incorporating body compositions were generated. The utility of developed models was evaluated by Harrell concordance index (C-index), calibration curve, and decision curve analysis (DCA).

RESULTS

Stratifying by X-tilederived cut points, low skeletal muscle index (myopenia), high intramuscular adipose tissue content (myosteatosis), and the ratio of high visceral to subcutaneous adipose tissue area (adiposity) was independently associated with 3-year mortality. A sex-stratified nomogram incorporating anthropometric indices and clinical factors resulted in moderate discriminative accuracy, with a C-index of 0.787 (95% CI, 0.736-0.838) and 0.789 (95% CI, 0.727-0.851) in males and females, respectively. The calibration curve showed predictive survival corresponding optimally with the actual outcomes. Our models were feasible in the clinical settings based on DCA. Similar results were observed in the validation cohort. Additionally, participants could be classified into 3 distinct risk groups by the nomogram.

CONCLUSIONS

Our proposed nomogram embedding body compositions rendered an individualized predictive tool for long-term mortality in cirrhosis.

Sarcopenia in cirrhosis: from pathogenesis to interventions

Sarcopenia (severe muscle depletion) is a prevalent muscle abnormality in patients with cirrhosis that confers poor prognosis both pre- and post-liver transplantation. The pathogenesis of sarcopenia is multifactorial and results from an imbalance between protein synthesis and breakdown. Nutritional, metabolic, and biochemical abnormalities seen in chronic liver disease alter whole body protein homeostasis. Hyperammonemia, increased autophagy, proteasomal activity, lower protein synthesis, and impaired mitochondrial function play an important role in muscle depletion in cirrhosis. Factors including cellular energy status, availability of metabolic substrates (e.g., branched-chain amino acids), alterations in the endocrine system (insulin resistance, circulating levels of insulin, insulin-like growth factor-1, corticosteroids, and testosterone), cytokines, myostatin, and exercise are involved in regulating muscle mass. A favored atrophy of type II fast-twitch glycolytic fibers seems to occur in patients with cirrhosis and sarcopenia. Identification of muscle biological abnormalities and underlying mechanisms is required to plan clinical trials to reverse sarcopenia through modulation of specific mechanisms. Accordingly, a combination of nutritional, physical, and pharmacological interventions might be necessary to reverse sarcopenia in cirrhosis. Moderate exercise should be combined with appropriate energy and protein intake, in accordance with clinical guidelines. Interventions with branched chain amino acids, testosterone, carnitine, or ammonia-lowering therapies should be considered individually. Various factors such as dose, type, duration of supplementations, etiology of cirrhosis, amount of dietary protein intake, and compliance with supplementation and exercise should be the focus of future large randomized controlled trials investigating both prevention and treatment of sarcopenia in this patient population.