Myostatin and beyond in cirrhosis: all roads lead to sarcopenia

Development and validation of an explainable machine learning model for predicting multidimensional frailty in hospitalized patients with cirrhosis

We sought to develop and validate a machine learning (ML) model for predicting multidimensional frailty based on clinical and laboratory data. Moreover, an explainable ML model utilizing SHapley Additive exPlanations (SHAP) was constructed. This study enrolled 622 patients hospitalized due to decompensating episodes at a tertiary hospital. The cohort data were randomly divided into training and test sets. External validation was carried out using 131 patients from other tertiary hospitals. The frail phenotype was defined according to a self-reported questionnaire (Frailty Index). The area under the receiver operating characteristics curve was adopted to compare the performance of five ML models. The importance of the features and interpretation of the ML models were determined using the SHAP method. The proportions of cirrhotic patients with nonfrail and frail phenotypes in combined training and test sets were 87.8% and 12.2%, respectively, while they were 88.5% and 11.5% in the external validation dataset. Five ML algorithms were used, and the random forest (RF) model exhibited substantially predictive performance. Regarding the external validation, the RF algorithm outperformed other ML models. Moreover, the SHAP method demonstrated that neutrophil-to-lymphocyte ratio, age, lymphocyte-to-monocyte ratio, ascites, and albumin served as the most important predictors for frailty. At the patient level, the SHAP force plot and decision plot exhibited a clinically meaningful explanation of the RF algorithm. We constructed an ML model (RF) providing accurate prediction of frail phenotype in decompensated cirrhosis. The explainability and generalizability may foster clinicians to understand contributors to this physiologically vulnerable situation and tailor interventions.

Ammonia transporter RhBG initiates downstream signaling and functional responses by activating NFκB

Transceptors, solute transporters that facilitate intracellular entry of molecules and also initiate intracellular signaling events, have been primarily studied in lower-order species. Ammonia, a cytotoxic endogenous metabolite, is converted to urea in hepatocytes for urinary excretion in mammals. During hyperammonemia, when hepatic metabolism is impaired, nonureagenic ammonia disposal occurs primarily in skeletal muscle. Increased ammonia uptake in skeletal muscle is mediated by a membrane-bound, 12 transmembrane domain solute transporter, Rhesus blood group-associated B glycoprotein (RhBG). We show that in addition to its transport function, RhBG interacts with myeloid differentiation primary response-88 (MyD88) to initiate an intracellular signaling cascade that culminates in activation of NFκB. We also show that ammonia-induced MyD88 signaling is independent of the canonical toll-like receptor-initiated mechanism of MyD88-dependent NFκB activation. In silico, in vitro, and in situ experiments show that the conserved cytosolic J-domain of the RhBG protein interacts with the Toll-interleukin-1 receptor (TIR) domain of MyD88. In skeletal muscle from human patients, human-induced pluripotent stem cell-derived myotubes, and myobundles show an interaction of RhBG-MyD88 during hyperammonemia. Using complementary experimental and multiomics analyses in murine myotubes and mice with muscle-specific RhBG or MyD88 deletion, we show that the RhBG-MyD88 interaction is essential for the activation of NFkB but not ammonia transport. Our studies show a paradigm of substrate-dependent regulation of transceptor function with the potential for modulation of cellular responses in mammalian systems by decoupling transport and signaling functions of transceptors.

Bedside assessment of sarcopenia in hospitalized patients with liver cirrhosis: Magnitude and clinical implications

BACKGROUND

Sarcopenia is associated with many adverse outcomes in patients with cirrhosis. The tools currently in use for assessing sarcopenia have numerous flaws. We evaluated the utility of portable ultrasonography and a dynamometer for the bedside assessment of sarcopenia and its implications in hospitalized cirrhosis patients.

METHODS

A dynamometer was used to test the hand-grip strength (HGS) and ultrasound was used to measure the thickness of the forearm and quadriceps muscles. HGS value < 27 kg for men and < 16 kg for women was taken as significant according to the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. The lower normal limit of muscle mass (5th percentile) was determined on 100 matched healthy controls.

RESULTS

According to the EWGSOP2 criteria and HGS values, the prevalence of sarcopenia and probable sarcopenia among 300 cirrhosis patients were 56% and 62.3%, respectively. HGS alone identified sarcopenia in 88.9% of patients, while overestimated it in 6.3% of cases. The prevalence rate of sarcopenic obesity was 11%. Compared to patients without sarcopenia, sarcopenic patients had more complications of cirrhosis such as ascites, variceal bleeding, hepatic encephalopathy, spontaneous bacterial peritonitis, sepsis, hepatorenal syndrome and refractory ascites. In-hospital (p = 0.037), three-month (p < 0.001), and six-month (p < 0.001) mortality rates were all higher among sarcopenic patients. On cox regression survival analysis, overall six-month mortality was significantly higher in sarcopenic patients compared to patients without sarcopenia (hazard ratio, 6.37; 95% confidence interval, 3.15-12.8, p < 0.001).

CONCLUSION

Bedside assessment of sarcopenia using a portable ultrasound machine and a dynamometer detects liver cirrhosis patients with high risk of complications and mortality.

Emerging drugs for the treatment of sarcopenia in cirrhosis of the liver

INTRODUCTION

Malnutrition and sarcopenia are common and impact the prognosis in patients with liver cirrhosis. The etiology is multifactorial and includes periods of reduced caloric intake, increased catabolism and direct molecular mechanisms that inhibit muscle synthesis. Although these conditions are widely acknowledged, and there is a growing interest in their diagnosis, robust evidence regarding the treatment and reversibility of these conditions is still lacking.

AREAS COVERED

We have explored the current evidence on the pharmacological treatment of sarcopenia in patients with cirrhosis. Additionally, we have searched for drugs already in use and ongoing trials for other chronic diseases.

EXPERT OPINION

The current guidelines recommend the use of a protein-adequate diet and moderate physical activity for treating sarcopenia in patients with cirrhosis. Currently, robust evidence is derived only from the supplementation of Branched-Chain Amino Acids, capable of increasing muscle mass and function. There are many drugs targeting various pathways that contribute to sarcopenia. However, evidence is sporadic and insufficient to suggest their use in clinical practice.Novel drugs specifically designed to enhance muscle mass and function should be developed. Finally, gender significantly influences the type of muscle alteration and therapeutic mechanisms; therefore, future studies should be designed taking gender differences into consideration.

Review article: Evaluation and care of the critically ill patient with cirrhosis

BACKGROUND

The increase in prevalence of liver disease globally will lead to a substantial incremental burden on intensive care requirements. While liver transplantation offers a potential life-saving intervention, not all patients are eligible due to limitations such as organ availability, resource constraints, ongoing sepsis or multiple organ failures. Consequently, the focus of critical care of patients with advanced and decompensated cirrhosis turns to liver-centric intensive care protocols, to mitigate the high mortality in such patients.

AIM

Provide an updated and comprehensive understanding of cirrhosis management in critical care, and which includes emergency care, secondary organ failure management (mechanical ventilation, renal replacement therapy, haemodynamic support and intensive care nutrition), use of innovative liver support systems, infection control, liver transplantation and palliative and end-of life care.

METHODS

We conducted a structured bibliographic search on PubMed, sourcing articles published up to 31 March 2024, to cover topics addressed. We considered data from observational studies, recommendations of society guidelines, systematic reviews, and meta-analyses, randomised controlled trials, and incorporated our clinical expertise in liver critical care.

RESULTS

Critical care management of the patient with cirrhosis has evolved over time while mortality remains high despite aggressive management with liver transplantation serving as a crucial but not universally available resource.

CONCLUSIONS

Implementation of organ support therapies, intensive care protocols, nutrition, palliative care and end-of-life discussions and decisions are an integral part of critical care of the patient with cirrhosis. A multi-disciplinary approach towards critical care management is likely to yield better outcomes.

Pathophysiology of Physical Exercise in Kidney Patients: Unveiling New Players - The Role of Myokines

BACKGROUND

Chronic kidney disease (CKD) is a progressive systemic condition characterized by numerous complications. Among these, alterations in skeletal muscle physiology, such as sarcopenia, are particularly significant, as they are associated with poor outcomes and reduced quality of life.

SUMMARY

Various interventions, including pharmacological approaches and lifestyle modifications have been investigated to slow CKD progression and prevent or treat its complications. Physical exercise, in particular, has emerged as a promising intervention with multiple beneficial effects. These include improvements in physical functioning, increased muscle mass, modulation of metabolic abnormalities, and reduced cardiovascular risk. However, the pathophysiology of physical exercise in patients with kidney disease is complex and remains only partially understood. A crucial advancement in understanding this phenomenon has been the identification of myokines - molecules expressed and released by skeletal muscle in response to physical activity. These myokines can exert both paracrine and systemic effects, influencing not only skeletal muscle physiology but also other processes such as energy metabolism and lipid regulation.

KEY MESSAGES

The interplay among skeletal muscle, physical activity, and myokines may act as a pivotal regulator in various physiological processes, including aging, as well as in pathological conditions like cachexia and sarcopenia, frequently observed in CKD patients at different stages, including patients on dialysis. Despite the potential importance of this relationship, only a limited number of studies have explored the relationship between exercise and myokine, and the effect of this interaction on experimental models or individuals with kidney disease. In the following sections, we review and discuss this topic.

Branched-chain amino acid supplementation does not improve measures of sarcopenia in cirrhosis: results of a randomised controlled trial

BACKGROUND

Sarcopenia is associated with adverse outcomes in cirrhosis. Branched-chain amino acids (BCAA) target several pathways that lead to muscle loss in this population.

AIMS

We aimed to evaluate the impact of BCAA supplementation on sarcopenia measures in patients with cirrhosis.

METHODS

We conducted a 12-month double-blinded, randomised, controlled trial of BCAA supplementation (30 g daily) compared to an equicaloric, equi-nitrogenous whey protein in volunteers with cirrhosis and reduced muscle strength. The primary endpoint was an increase in grip strength and upper limb lean mass measured on DEXA. Mean-adjusted differences (MAD, 95% CI) between groups at 6 and 12 months are reported as treatment effect using a linear mixed model for repeated measures.

RESULTS

A total of 150 volunteers entered the trial (74 BCAA, 76 control), with a median age of 58 years [IQR 48; 63] and MELD of 14 [12; 17]. At 12 months, 57% in the BCAA arm and 61% in the control arm met the primary endpoint (p = 0.80). No significant between-group difference was found in grip strength (MAD -0.15 kg [-0.37; 0.06], p = 0.29) or upper limb lean mass (1.7 kg [-0.2; 3.6], p = 0.22) at 12 months. No significant differences in other body composition parameters, physical performance, frailty, rates of hospitalisation or mortality were found between the BCAA and the control group. Fatigue improved across the entire cohort, without significant between-group differences. 15% of volunteers reported side effects, with distaste higher in the BCAA arm (p = 0.045).

CONCLUSION

BCAA supplementation did not improve measures of muscle strength, mass or performance or physical frailty compared to a whey protein supplement in a randomised controlled setting. ACTRN12618000802202.

Approaching the Sarcopenic Patient with Nonalcoholic Steatohepatitis-related Cirrhosis

Sarcopenia is a well-known complication of chronic liver disease (CLD), and it is almost always observed in patients with cirrhosis, at least in those with decompensated disease. Since nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is becoming the leading cause of end-stage liver disease, a new scenario characterized by the frequent coexistence of NAFLD, obesity, and sarcopenia is emerging. Although it is not yet resolved whether the bidirectional relationship between sarcopenia and NAFLD subtends causal determinants, it is clear that the interaction of these two conditions is associated with an increased risk of poor outcomes. Notably, during the course of CLD, deregulation of the liver-muscle-adipose tissue axis has been described. Unfortunately, owing to the lack of properly designed studies, specific therapeutic guidelines for patients with sarcopenia in the context of NAFLD-related CLD have not yet been defined. Strategies aimed to induce the loss of fat mass together with the maintenance of lean body mass seem most appropriate. This can be achieved by properly designed diets integrated with specific nutritional supplementations and accompanied by adequate physical exercise. Future studies aiming to add to the knowledge of the correct assessment and approach to sarcopenia in the context of NAFLD-related CLD are eagerly awaited.

Mechanistically based blood proteomic markers in the TGF-β pathway stratify risk of hepatocellular cancer in patients with cirrhosis

Hepatocellular carcinoma (HCC) is the third leading cause of death from cancer worldwide but is often diagnosed at an advanced incurable stage. Yet, despite the urgent need for blood-based biomarkers for early detection, few studies capture ongoing biology to identify risk-stratifying biomarkers. We address this gap using the TGF-β pathway because of its biological role in liver disease and cancer, established through rigorous animal models and human studies. Using machine learning methods with blood levels of 108 proteomic markers in the TGF-β family, we found a pattern that differentiates HCC from non-HCC in a cohort of 216 patients with cirrhosis, which we refer to as TGF-β based Protein Markers for Early Detection of HCC (TPEARLE) comprising 31 markers. Notably, 20 of the patients with cirrhosis alone presented an HCC-like pattern, suggesting that they may be a group with as yet undetected HCC or at high risk for developing HCC. In addition, we found two other biologically relevant markers, Myostatin and Pyruvate Kinase M2 (PKM2), which were significantly associated with HCC. We tested these for risk stratification of HCC in multivariable models adjusted for demographic and clinical variables, as well as batch and site. These markers reflect ongoing biology in the liver. They potentially indicate the presence of HCC early in its evolution and before it is manifest as a detectable lesion, thereby providing a set of markers that may be able to stratify risk for HCC.

Association of Muscle Mass Loss with Diabetes Development in Liver Transplantation Recipients

BACKGRUOUND

Post-transplant diabetes mellitus (PTDM) is one of the most significant complications after transplantation. Patients with end-stage liver diseases requiring transplantation are prone to sarcopenia, but the association between sarcopenia and PTDM remains to be elucidated. We aimed to investigate the effect of postoperative muscle mass loss on PTDM development.

METHODS

A total of 500 patients who underwent liver transplantation at a tertiary care hospital between 2005 and 2020 were included. Skeletal muscle area at the level of the L3-L5 vertebrae was measured using computed tomography scans performed before and 1 year after the transplantation. The associations between the change in the muscle area after the transplantation and the incidence of PTDM was investigated using a Cox proportional hazard model.

RESULTS

During the follow-up period (median, 4.9 years), PTDM occurred in 165 patients (33%). The muscle mass loss was greater in patients who developed PTDM than in those without PTDM. Muscle depletion significantly increased risk of developing PTDM after adjustment for other confounding factors (hazard ratio, 1.50; 95% confidence interval, 1.23 to 1.84; P=0.001). Of the 357 subjects who had muscle mass loss, 124 (34.7%) developed PTDM, whereas of the 143 patients in the muscle mass maintenance group, 41 (28.7%) developed PTDM. The cumulative incidence of PTDM was significantly higher in patients with muscle loss than in patients without muscle loss (P=0.034).

CONCLUSION

Muscle depletion after liver transplantation is associated with increased risk of PTDM development.

Portal Hypertension in Malnutrition and Sarcopenia in Decompensated Cirrhosis-Pathogenesis, Implications and Therapeutic Opportunities

Malnutrition and sarcopenia are highly prevalent in patients with decompensated cirrhosis and are associated with poorer clinical outcomes. Their pathophysiology is complex and multifactorial, with protein-calorie malnutrition, systemic inflammation, reduced glycogen stores and hormonal imbalances all well reported. The direct contribution of portal hypertension to these driving factors is however not widely documented in the literature. This review details the specific mechanisms by which portal hypertension directly contributes to the development of malnutrition and sarcopenia in cirrhosis. We summarise the existing literature describing treatment strategies that specifically aim to reduce portal pressures and their impact on nutritional and muscle outcomes, which is particularly relevant to those with end-stage disease awaiting liver transplantation.

Frailty in end-stage liver disease: Understanding pathophysiology, tools for assessment, and strategies for management

Frailty and sarcopenia are frequently observed in patients with end-stage liver disease. Frailty is a complex condition that arises from deteriorations across various physiological systems, including the musculoskeletal, cardiovascular, and immune systems, resulting in a reduced ability of the body to withstand stressors. This condition is associated with declined resilience and increased vulnerability to negative outcomes, including disability, hospitalization, and mortality. In cirrhotic patients, frailty is influenced by multiple factors, such as hyperammonemia, hormonal imbalance, malnutrition, ascites, hepatic encephalopathy, and alcohol intake. Assessing frailty is crucial in predicting morbidity and mortality in cirrhotic patients. It can aid in making critical decisions regarding patients' eligibility for critical care and transplantation. This, in turn, can guide the development of an individualized treatment plan for each patient with cirrhosis, with a focus on prioritizing exercise, proper nutrition, and appropriate treatment of hepatic complications as the primary lines of treatment. In this review, we aim to explore the topic of frailty in liver diseases, with a particular emphasis on pathophysiology, clinical assessment, and discuss strategies for preventing frailty through effective treatment of hepatic complications. Furthermore, we explore novel assessment and management strategies that have emerged in recent years, including the use of wearable technology and telemedicine.

[Sarcopenia in Chronic Liver Disease]

Sarcopenia is a crucial factor in assessing the nutritional status of chronic liver disease patients and predicting their prognosis and survival. The serum ammonia level is closely associated with sarcopenia regarding ammonia, a key regulator in the liver-muscle axis. In addition, various changes in energy metabolism and hormones are also involved in sarcopenia. The psoas muscle area can represent the overall skeletal muscle mass in liver disease patients. Therefore, measuring the psoas muscle area with computed tomography or magnetic resonance imaging is considered an objective and reliable method for assessing muscle mass. Providing sufficient calorie and protein intake is crucial for preventing and treating sarcopenia. In addition, engaging in appropriate exercise and addressing concurrent hormonal and metabolic changes can be helpful.

Body composition and short-term mortality in patients critically ill with acute-on-chronic liver failure

Background & Aims

Body composition is sex dependent and associated with an increased mortality risk in patients with cirrhosis. We evaluated whether it was also associated with short-term mortality in patients critically ill with acute-on-chronic liver failure (ACLF).

Patients and methods

We retrospectively included all patients with cirrhosis and ACLF hospitalised in the intensive care unit (ICU) of Lausanne University Hospital between 2010 and 2019 for whom an abdominal computed tomography (CT) scan performed ±7 days from admission was available. Patients from the ICU of Paul Brousse University Hospital admitted between 2017 and 2020 served as an external cohort. All body composition parameters at the third lumbar vertebral level (L3) were quantified using a deep learning-based method.

Results

In total, 192 patients from Lausanne were included. Median age was 62 years and 28-day survival rate was 58.2%. In males, variables independently associated with 28-day mortality on days 1 and 3 were Chronic Liver Failure Consortium (CLIF-C) ACLF-lactate and sarcopenia. In females, CLIF-C ACLF-lactate on days 1 and 3 was the only predictor of 28-day survival. We derived two scores combining sarcopenia and the CLIF-C ACLF-lactate score on days 1 and 3, with area under the receiver operating characteristic outperforming the CLIF-C ACLF-lactate score alone in male but not in female patients. Comparable results were found in the external cohort of 58 patients and supported the sex specificity of the performance of the model. Patients with sarcopenia had increased risks of invasive fungal infection and renal replacement therapy.

Conclusion

Sarcopenia was associated with 28-day mortality in male but not in female patients critically ill with ACLF. Although screening for sarcopenia could impact the management of male patients, further studies are needed in female cohorts to investigate whether other body composition parameters are associated with outcomes.

Impact and implications

Body composition, easily assessed by CT, is altered in patients with cirrhosis and associated with outcome; it has never been investigated in patients critically ill with ACLF. The results of the present study, underlining the benefit of sarcopenia evaluation to improve prognosis prediction in males critically ill with ACLF, are of importance for physicians managing such patients to optimise the decision-making process toward continued treatment, liver transplantation, or limitation of care. In a wider sense, besides the number and course of organ failures, the results recall the weight of the general condition of males with ACLF at admission to ICU. In females critically ill with ACLF, in analyses limited by the sample size, none of the body composition parameters was associated with short-term mortality independently of organ failures; this suggests that the number and course of organ failures are the main determinant of mortality in these patients.

Mechanisms of sarcopenia in liver cirrhosis and the role of myokines

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

Liver transplantation in the patient with physical frailty

Frailty is a decline in functional reserve across multiple physiological systems. A key component of frailty is sarcopenia, which denotes a loss of skeletal muscle mass and impaired contractile function that ultimately result in physical frailty. Physical frailty/sarcopenia are frequent and contribute to adverse clinical outcomes before and after liver transplantation. Frailty indices, including the liver frailty index, focus on contractile dysfunction (physical frailty), while cross-sectional image analysis of muscle area is the most accepted and reproducible measure to define sarcopenia. Thus, physical frailty and sarcopenia are interrelated. The prevalence of physical frailty/sarcopenia is high in liver transplant candidates and these conditions have been shown to adversely impact clinical outcomes including mortality, hospitalisations, infections, and cost of care both before and after transplantation. Data on the prevalence of frailty/sarcopenia and their sex- and age-dependent impact on outcomes are not consistent in patients on the liver transplant waitlist. Physical frailty and sarcopenic obesity are frequent in the obese patient with cirrhosis, and adversely affect outcomes after liver transplantation. Nutritional interventions and physical activity remain the mainstay of management before and after transplantation, despite limited data from large scale trials. In addition to physical frailty, there is recognition that a global evaluation including a multidisciplinary approach to other components of frailty (e.g., cognition, emotional, psychosocial) also need to be addressed in patients on the transplant waitlist. Recent advances in our understanding of the underlying mechanisms of sarcopenia and contractile dysfunction have helped identify novel therapeutic targets.

Fortetropin supplementation prevents the rise in circulating myostatin but not disuse-induced muscle atrophy in young men with limb immobilization: A randomized controlled trial

Supplementation with Fortetropin® (FOR), a naturally occurring component from fertilized egg yolks, reduces circulating myostatin concentration. We hypothesized that FOR would mitigate muscle atrophy during immobilization. We examined the effect of FOR supplementation on muscle size and strength during 2-wk of single-leg immobilization and recovery. Twenty-four healthy young men (22 ± 2 yrs; BMI = 24.3 ± 2.9 kg/m2) were randomly allocated to either a Fortetropin® supplement (FOR-SUPP, n = 12) group consuming 19.8 g/d of FOR or placebo (PLA-SUPP, n = 12) group consuming energy- and macronutrient-matched cheese powder for 6-wk. The 6-wk period consisted of 2-wk run-in, 2-wk single-leg immobilization, and 2-wk recovery phase returning to habitual physical activities. Ultrasonography, dual-energy X-ray absorptiometry, muscle biopsies and isometric peak torque assessments were performed prior to and following each phase (days 1, 14, 28, and 42) to measure vastus lateralis and muscle fiber cross-section area (CSA), leg lean mass (LM), and muscular strength. Blood samples were taken on days 1 and 42 for measurement of plasma myostatin concentration, which increased in PLA-SUPP (4221 ± 541 pg/mL to 6721 ± 864 pg/mL, P = 0.013) but not in FOR-SUPP (5487 ± 489 pg/mL to 5383 ± 781 pg/mL, P = 0.900). After the immobilization phase, vastus lateralis CSA, LM, and isometric peak torque were decreased by 7.9 ± 1.7% (P < 0.001), -1.6 ± 0.6% (P = 0.037), and -18.7 ± 2.7% (P < 0.001) respectively, with no difference between groups. The decreased peak torque was recovered after 2-wk of normal activity (vs. day 1, P = 0.129); however, CSA and LM were not recovered (vs. day 1, P < 0.001 and P = 0.003, respectively), with no differences between groups. Supplementation with FOR prevented the rise in circulating myostatin but not disuse-induced muscle atrophy in young men after 2-wk of single-leg immobilization.

Current vision on diagnosis and comprehensive care in hepatic encephalopathy

The first clinical guidelines on hepatic encephalopathy were published in 2009. Almost 14 years since that first publication, numerous advances in the field of diagnosis, treatment, and special condition care have been made. Therefore, as an initiative of the Asociación Mexicana de Gastroenterología A.C., we present a current view of those aspects. The manuscript described herein was formulated by 24 experts that participated in six working groups, analyzing, discussing, and summarizing the following topics: Definition of hepatic encephalopathy; recommended classifications; epidemiologic panorama, worldwide and in Mexico; diagnostic tools; conditions that merit a differential diagnosis; treatment; and primary and secondary prophylaxis. Likewise, these guidelines emphasize the management of certain special conditions, such as hepatic encephalopathy in acute liver failure and acute-on-chronic liver failure, as well as specific care in patients with hepatic encephalopathy, such as the use of medications and types of sedation, describing those that are permitted or recommended, and those that are not.

Hepatic encephalopathy - recent advances in treatment and diagnosis

INTRODUCTION

Hepatic encephalopathy (HE) is a peculiar kind of brain dysfunction typical of liver cirrhosis characterized by nonspecific neurological and psychiatric manifestations. HE ranges from minimal hepatic encephalopathy (MHE) to the most severe form characterized by alteration of consciousness or coma (overt HE, OHE). Once the diagnosis of OHE is made, every effort to identify and correct the precipitating cause is essential for the resolution of symptoms. Clinical studies that assessed the prevalence and incidence of any type of HE (MHE and OHE) in patients affected by cirrhosis were included in this review. No language, publication date, or publication status restrictions were imposed. The studies were identified by searching electronic databases (PubMed and SCOPUS).

AREAS COVERED

The most widely empirical pharmacological approach consists of non-absorbable antibiotics (rifaximin) and non-absorbable disaccharides (lactulose, lactitol per os and per enemas). Other agents (including branched-chain amino acids, probiotics, other antibiotics, or intravenous L-ornithine L-aspartate) are available, but the evidence supporting their efficacy remains under debate.

EXPERT OPINION

Gray areas and future needs remain the therapeutic approach to MHE and issues in the design of therapeutic studies for HE which have been extensively discussed in this review.

Sarcopenia in the Cirrhotic Patient: Current Knowledge and Future Directions

Cirrhosis predisposes to abnormalities in energy, hormonal, and immunological homeostasis. Disturbances in these metabolic processes create susceptibility to sarcopenia or pathological muscle wasting. Sarcopenia is prevalent in cirrhosis and its presence portends significant adverse outcomes including the length of hospital stay, infectious complications, and mortality. This highlights the importance of identification of at-risk individuals with early nutritional, therapeutic and physical therapy intervention. This manuscript summarizes literature relevant to sarcopenia in cirrhosis, describes current knowledge, and elucidates possible future directions.

Placental transfer of bisphenol diglycidyl ethers (BDGEs) and its association with maternal health in a population in South of China

Despite high production and usage, little is known about exposure to bisphenol diglycidyl ethers (BDGEs) and their derivatives in pregnant women and fetuses. In this study, we determined nine BDGEs in 106 paired maternal and cord serum samples collected from e-waste dismantling sites in South of China. Bisphenol A bis (2,3-dihydroxypropyl) glycidyl ether (BADGE·2H2O), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) glycidyl ether (BADGE·HCl·H2O), and bisphenol F diglycidyl ether (BFDGE) were the major BDGEs, with median concentrations of 0.57, 4.07, and 1.60 ng/mL, respectively, in maternal serum, and of 3.58, 5.61, and 0.61 ng/mL, respectively, in cord serum. The transplacental transfer efficiencies (TTEs) were estimated for BDGEs found in samples, and median values were in the range of 0.98 (BFDGE) to 5.91 (BADGE·2H2O). Our results suggested that passive diffusion plays a role in the placental transfer of BADGE·HCl·H2O and BFDGE, whereas several mechanisms contribute to the high accumulation of BADGE·2H2O in cord serum. Multiple linear regression analysis indicated significant associations between maternal serum concentrations of BDGEs and blood clinical biomarkers, especially those related to liver injuries, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and adenosine deaminase (ADA) (P < 0.05). To our knowledge, this is the first study to report the occurrence of BDGEs in paired maternal-fetal serum samples and provide new insights into prenatal and fetal exposures. The newly discovered TTEs in maternal-fetal pairs contribute to a fuller inventory of the transmission activity of pollutants in the human body, ultimately adding to a more significant comprehensive risk evaluation.

Perspectives on Sarcopenia as a Predictor for Outcomes in Pediatric Patients with Chronic Liver Disease

Sarcopenia, a pathologic deficiency of muscle mass and function, has emerged as an important secondary feature of many chronic disease states. For adults with end stage liver disease, there are multiple mechanisms which contribute to sarcopenia and its presence has proven to be an important predictor of morbidity and mortality. In children, there are only a limited number of reports which investigate the role of sarcopenia in liver disease. These studies, which are discussed and summarized in this review, report small, single-center analyses with dissimilar study cohorts and varying clinical definitions. Still, children meeting the study entry criteria have sarcopenia with a reported prevalence of 24-70%. When assessed, sarcopenia appears to be associated with more severe disease but is independent of the Pediatric End-Stage Liver Disease (PELD) score and does not correlate with age, gender, or traditional anthropometric measures such as weight, height, weight-for-height, or body mass index (BMI). While individual studies may identify sarcopenia as a statistically significant risk factor for certain post-transplant outcomes such as longer ICU stay, longer duration of intubation, repeat operation, development of serious infection, longer hospital stay, death, or long-term growth failure, such associations are not consistently replicated across studies. Finally, although various methods of muscle mass quantification are utilized, the most reported is the total psoas muscle surface area (tPMSA) on computed tomography. This method, along with others such as skeletal muscle area and skeletal muscle index, have had normative values recently defined and these collective efforts should enable researchers a common basis of comparison when delineating sarcopenia, and its impact, across various study populations in future investigations - including in children with liver disease.

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.

Ammonia and the Muscle: An Emerging Point of View on Hepatic Encephalopathy

In the last years the link between the presence of muscular alterations and hepatic encephalopathy (HE), both minimal and overt, has been deeply studied. The pathophysiological background supporting the relationship between muscle depletion, and HE is characterized by an imbalance between the capacity of muscle in ammonia metabolism and trafficking and the inability of the liver in removing ammonia through urea synthesis due to liver failure and/or the presence of porto-systemic shunts. This review will focus on the clinical burden, the physio pathological mechanisms understanding the liver muscle axis and principles of management of muscular alterations in cirrhosis.

Myostatin: Basic biology to clinical application

Myostatin is a member of the transforming growth factor (TGF)-β superfamily. It is expressed by animal and human skeletal muscle cells where it limits muscle growth and promotes protein breakdown. Its effects are influenced by complex mechanisms including transcriptional and epigenetic regulation and modulation by extracellular binding proteins. Due to its actions in promoting muscle atrophy and cachexia, myostatin has been investigated as a promising therapeutic target to counteract muscle mass loss in experimental models and patients affected by different muscle-wasting conditions. Moreover, growing evidence indicates that myostatin, beyond to regulate skeletal muscle growth, may have a role in many physiologic and pathologic processes, such as obesity, insulin resistance, cardiovascular and chronic kidney disease. In this chapter, we review myostatin biology, including intracellular and extracellular regulatory pathways, and the role of myostatin in modulating physiologic processes, such as muscle growth and aging. Moreover, we discuss the most relevant experimental and clinical evidence supporting the extra-muscle effects of myostatin. Finally, we consider the main strategies developed and tested to inhibit myostatin in clinical trials and discuss the limits and future perspectives of the research on myostatin.

The Prophylactic Effects of Glutamine on Muscle Protein Synthesis and Degradation in Rats with Ethanol-Induced Liver Damage

The purpose of this research was to investigate the prophylactic effects of glutamine on muscle protein synthesis and degradation in rats with ethanol-induced liver injury. For the first 2 weeks, Wistar rats were divided into two groups and fed a control (n = 16) or glutamine-containing diet (n = 24). For the following 6 weeks, rats fed the control diet were further divided into two groups (n = 8 per group) according to whether their diet contained no ethanol (CC) or did contain ethanol (CE). Rats fed the glutamine-containing diet were also further divided into three groups (n = 8 per group), including a GG group (glutamine-containing diet without ethanol), GE group (control diet with ethanol), and GEG group (glutamine-containing diet with ethanol). After 6 weeks, results showed that hepatic fatty change, inflammation, altered liver function, and hyperammonemia had occurred in the CE group, but these were attenuated in the GE and GEG groups. Elevated intestinal permeability and a higher plasma endotoxin level were observed in the CE group, but both were lower in the GE and GEG groups. The level of a protein synthesis marker (p70S6K) was reduced in the CE group but was higher in both the GE and GEG groups. In conclusion, glutamine supplementation might elevate muscle protein synthesis by improving intestinal health and ameliorating liver damage in rats with chronic ethanol intake.

In a Randomized, Placebo-Controlled Cross-Over Study, Administration of 6 and 12 G Fortetropin® Does Not Reduce Serum Myostatin in Healthy Adult Dogs Over 72-Hours

Objective: To evaluate the effect of a single administration of 6 and 12 g of Fortetropin compared to placebo on serum myostatin in healthy, adult dogs over a 72-h period.

Methods: Prospective, placebo-controlled, randomized, double-blind, crossover study. Ten hospital-employee-owned healthy adult dogs aged 2 to 8 years old were enrolled in the study. Blood samples were collected prior to and then 12-, 24-, 36-, 48-, and 72-h following administration of the test agent (6 and 12 g) or placebo. Serum samples were processed according to manufacturer's guidelines for canine serum using GDF-8/Myostatin Quantikine ELISA kit (R&D Systems). Analysis-of-variance (ANOVA) analyses were carried out where P < 0.05 was deemed significant.

Results: Mean serum myostatin was not significantly lower in treatment groups of either low or high dose compared to placebo at any time point. Baseline mean serum myostatin in low and high dose treatment groups was 29,481 (SD = 5,224) and 32,214 pg/mL (SD = 7,353), respectively. Placebo group low and high dose baseline mean serum myostatin was 30,247 (SD = 5,875) and 28,512 (SD = 5,028).

Conclusion: The results of this study indicate that administration of single 6 or 12 g dose of Fortetropin does not reduce serum myostatin in healthy adult dogs over a 72-h period.

Clinical Importance: Oral supplements, like Fortetropin, require further studies to determine the efficacy and bioavailability in order to guide clinical use in dogs.

Sarcopenia and frailty in decompensated cirrhosis

In patients with decompensated cirrhosis, sarcopenia and frailty are prevalent. Although several definitions exist for these terms, in the field of hepatology, sarcopenia has commonly been defined as loss of muscle mass, and frailty has been broadly defined as the phenotypic manifestation of the loss of muscle function. Prompt recognition and accurate assessment of these conditions are critical as they are both strongly associated with morbidity, mortality, poor quality of life and worse post-liver transplant outcomes in patients with cirrhosis. In this review, we describe the complex pathophysiology that underlies the clinical phenotypes of sarcopenia and frailty, their association with decompensation, and provide an overview of tools to assess these conditions in patients with cirrhosis. When available, we highlight data focusing on patients with acutely decompensated cirrhosis, such as inpatients, as this is an area of unmet clinical need. Finally, we discuss management strategies to reverse and/or prevent the development of sarcopenia and frailty, which include adequate nutritional intake of calories and protein, as well as regular exercise of at least moderate intensity, with a mix of aerobic and resistance training. Key knowledge gaps in our understanding of sarcopenia and frailty in decompensated cirrhosis remain, including best methods to measure muscle mass and function in the inpatient setting, racial/ethnic variation in the development and presentation of sarcopenia and frailty, and optimal clinical metrics to assess response to therapeutic interventions that translate into a reduction in adverse outcomes associated with these conditions.

Factors Associated With Longitudinal QOL Change in Patients With Chronic Liver Diseases

AIM

To examine the relationship between longitudinal quality of life (QOL) change, as assessed by the 36-Item Short Form Health Survey (SF-36), sarcopenia-related factors and body composition in patients with chronic liver diseases (CLDs).

PATIENTS AND METHODS

Data from patients with CLDs (n=184) were retrospectively analyzed, focusing on factors associated with the difference of physical and mental component summary score (PCS and MCS) in SF-36 between the two visits (Δ_PCS and Δ_MCS). The difference of serum albumin level, body mass index (BMI), arm circumference, arm muscle circumference, grip strength (GS), skeletal muscle index, extracellular to total body water ratio between the two visits were included into the multiple regression analysis.

RESULTS

Δ_albumin (p=0.0325) and Δ_GS (p<0.0001) were independent factors linked to Δ_PCS Δ_albumin (p=0.0005) and Δ_BMI (p=0.0232) were independent factors linked to Δ_MCS Conclusion: Significance of serum albumin level, muscle strength and body composition on health-related QOL in CLD patients should be emphasized.

Sarcopenia and Frailty in Liver Cirrhosis

Skeletal muscle is the largest organ in the body, and skeletal muscle atrophy results from a shift in the balance of protein synthesis and degradation toward protein breakdown. Primary sarcopenia is defined as a loss of skeletal muscle mass and strength or physical function due to aging, and secondary sarcopenia is defined as a loss of skeletal muscle mass and strength or physical function due to underlying diseases. Liver cirrhosis (LC) is one of the representative diseases which can be complicated with secondary sarcopenia. Muscle mass loss becomes more pronounced with worsening liver reserve in LC patients. While frailty encompasses a state of increased vulnerability to environmental factors, there is also the reversibility of returning to a healthy state with appropriate intervention. Several assessment criteria for sarcopenia and frailty were proposed in recent years. In 2016, the Japan Society of Hepatology created assessment criteria for sarcopenia in liver disease. In Japan, health checkups for frailty in the elderly aged 75 years or more started in April 2020. Both sarcopenia and frailty can be adverse predictors for cirrhotic patients. In this review article, we will summarize the current knowledge of sarcopenia and frailty in LC patients.

Tale of the Frail: Understanding Frailty in Cirrhosis

Frailty is a dynamic condition that results in increased vulnerability to health stressors. Often associated with older adults, frailty is not limited to the geriatric population, although aging and disease burden often go hand in hand. This syndrome is recognized increasingly as an important factor in healthcare costs, rate of adverse outcomes, and overall resource utilization. Frailty may be reversible to a degree, and thus appropriate recognition affords a focus for efficient intervention. Notably, frailty is becoming increasingly relevant in cirrhosis, and has been noted to be an independent predictor of outcomes in patients both before and after liver transplantation. Cirrhosis is currently the 12th leading cause of death in the United States, and its incidence is anticipated to markedly increase in the coming years with the aging of our population. With the anticipated surge in disease prevalence, liver disease care will likely shift from specialist-driven to a multidisciplinary approach between primary care physicians, internists, and hepatologists to adequately care for these patients. This review serves as a guide for clinicians to learn about frailty, its role in cirrhosis, and the current tools to educate patients and families about the importance of nutrition and physical exercise within this population.

Emerging Treatment Options for Sarcopenia in Chronic Liver Disease

Sarcopenia is characterized by a skeletal muscle disorder with progressive and generalized loss of muscle mass and function, and it increases the risk of adverse outcomes with considerable prevalence in patients with chronic liver disease. Sarcopenia in chronic liver disease underlies complicated and multifactorial mechanisms for pathogenesis, including alterations in protein turnover, hyperammonemia, energy disposal, hormonal changes, and chronic inflammation. The key contribution to sarcopenia in patients with chronic liver diseases can be the hyperammonemia-induced upregulation of myostatin, which causes muscle atrophy via the expression of atrophy-related genes. Several clinical studies on emerging treatment options for sarcopenia have been reported, but only a few have focused on patients with chronic liver diseases, with mostly nutritional and behavioral interventions being carried out. The inhibition of the myostatin-activin receptor signaling pathway and hormonal therapy might be the most promising therapeutic options in combination with an ammonia-lowering approach in sarcopenic patients with chronic liver diseases. This review focuses on current and emerging treatment options for sarcopenia in chronic liver diseases with underlying mechanisms to counteract this condition.

An Overview of the Molecular Mechanisms Contributing to Musculoskeletal Disorders in Chronic Liver Disease: Osteoporosis, Sarcopenia, and Osteoporotic Sarcopenia

The prevalence of osteoporosis and sarcopenia is significantly higher in patients with liver disease than in those without liver disease and osteoporosis and sarcopenia negatively influence morbidity and mortality in liver disease, yet these musculoskeletal disorders are frequently overlooked in clinical practice for patients with chronic liver disease. The objective of this review is to provide a comprehensive understanding of the molecular mechanisms of musculoskeletal disorders accompanying the pathogenesis of liver disease. The increased bone resorption through the receptor activator of nuclear factor kappa (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) system and upregulation of inflammatory cytokines and decreased bone formation through increased bilirubin and sclerostin and lower insulin-like growth factor-1 are important mechanisms for osteoporosis in patients with liver disease. Sarcopenia is associated with insulin resistance and obesity in non-alcoholic fatty liver disease, whereas hyperammonemia, low amount of branched chain amino acids, and hypogonadism contributes to sarcopenia in liver cirrhosis. The bidirectional crosstalk between muscle and bone through myostatin, irisin, β-aminoisobutyric acid (BAIBA), osteocalcin, as well as the activation of the RANK and the Wnt/β-catenin pathways are associated with osteosarcopenia. The increased understandings for these musculoskeletal disorders would be contributes to the development of effective therapies targeting the pathophysiological mechanism involved.

Frailty and Sarcopenia in Patients Pre- and Post-Liver Transplant

Greater than half of patients with decompensated liver disease suffer from frailty and/or sarcopenia, which can lead to increased pre- and post-liver transplant morbidity and mortality. Although frailty and sarcopenia can impact patients with end-stage liver disease in similar ways, they are unique clinical entities with differing underlying etiologies. Early assessment and identification of frailty and sarcopenia in patients is critical to guide clinical decision-making regarding transplantation and to implement nutritional and exercise-based treatment regiments. Nonetheless, accurate diagnosis and, in particular, predicting patients that will develop frailty and/or sarcopenia remains challenging, and the success of clinical interventions is limited.

The effect of malnutrition on the infectious outcomes of hospitalized patients with cirrhosis: analysis of the 2011-2017 hospital data

BACKGROUND

In patients with cirrhosis, there is a clinical concern that the development of protein-calorie malnutrition will affect the immune system and predispose these patients to increased infectious outcomes.

AIMS

In this study, we evaluate the effects of malnutrition on the infectious outcomes of patients admitted with cirrhosis.

MATERIALS AND METHODS

This study used the 2011-2017 National Inpatient Sample to identify patients with cirrhosis. These patients were stratified using malnutrition (protein-calorie malnutrition, cachexia, and sarcopenia) and matched using age, gender, and race with 1:1 nearest neighbor matching method. The endpoints included mortality and infectious outcomes.

RESULTS

After matching, there were 96 842 malnutrition-present cohort and equal number of controls. In univariate analysis, the malnutrition cohort had higher hospital mortality [10.40 vs. 5.04% P < 0.01, odds ratio (OR) 2.18, 95% confidence interval (CI) 2.11-2.26]. In multivariate models, malnutrition was associated with increased mortality [P < 0.01, adjusted odds ratio (aOR) 1.32, 95% CI 1.27-1.37] and infectious outcomes, including sepsis (P < 0.01, aOR 1.94, 95% CI 1.89-2.00), pneumonia (P < 0.01, aOR 1.68, 95% CI 1.63-1.73), UTI (P < 0.01, aOR 1.39, 95% CI 1.35-1.43), cellulitis (P < 0.01, aOR 1.09, 95% CI 1.05-1.13), cholangitis (P < 0.01, aOR 1.39, 95% CI 1.26-1.55), and clostridium difficile (P < 0.01, aOR 2.11, 95% CI 1.92-2.31).

CONCLUSION

The results of this study indicate that malnutrition is an independent risk factor of hospital mortality and local/systemic infections in patients admitted with cirrhosis.

Serum Myostatin Predicts the Risk of Hepatocellular Carcinoma in Patients with Alcoholic Cirrhosis: A Multicenter Study

Background and Aim: Previous studies reported that serum myostatin is associated with sarcopenia. We aimed to elucidate the association between serum myostatin levels and hepatocellular carcinoma (HCC) development in patients with alcoholic liver cirrhosis (ALC). Methods: This retrospective, multicenter study assessed 1077 Asian ALC patients enrolled from 2007 to 2017. The primary endpoint was the development of HCC within 5 years. Cox proportional hazards model analyses were used to assess the association of serum myostatin levels and HCC development. The time-dependent areas under the receiver operating characteristic curve (AUROC) of serum myostatin for 5-year HCC development were calculated. Serum myostatin levels were measured using an enzyme-linked immunosorbent assay with samples collected on the index date. Results: During a median follow-up of 2.5 years, 5-year cumulative HCC incidence rates were 6.7% in the total population. The median level of serum myostatin was 3.3 ng/mL (interquartile, 2.1-5.2 ng/mL). The AUROC of serum myostatin for 5-year HCC development was 0.78 (95% confidence interval [CI], 0.76-0.81). In Cox proportional hazards model analyses, age, gender, platelet counts, and serum myostatin levels were independent risk factors for HCC development (adjusted hazard ratios [HRs] of age, male gender, platelet counts, and serum myostatin: 1.03, 2.79, 0.996, 1.18, respectively; all p < 0.05). Patients with high myostatin levels had a significantly higher risk of 5-year HCC development than those with low myostatin levels (HR 7.53, p < 0.001). Conclusion: Higher serum myostatin levels were significantly associated with a higher risk of developing HCC in ALC patients, which could identify high-risk patients who need stringent surveillance.

Liver Cirrhosis and Sarcopenia from the Viewpoint of Dysbiosis

Sarcopenia in patients with liver cirrhosis (LC) has been attracting much attention these days because of the close linkage to adverse outcomes. LC can be related to secondary sarcopenia due to protein metabolic disorders and energy metabolic disorders. LC is associated with profound alterations in gut microbiota and injuries at the different levels of defensive mechanisms of the intestinal barrier. Dysbiosis refers to a state in which the diversity of gut microbiota is decreased by decreasing the bacterial species and the number of bacteria that compose the gut microbiota. The severe disturbance of intestinal barrier in LC can result in dysbiosis, several bacterial infections, LC-related complications, and sarcopenia. Here in this review, we will summarize the current knowledge of the relationship between sarcopenia and dysbiosis in patients with LC.

Assessment of Hemodynamic Parameters in Recipients of a Liver Transplant

INTRODUCTION

The control of all hemodynamic parameters among patients after liver transplantation is critical for better graft survival and to reduce the risk of perioperative complications. The value of cardiac output (CO) and stroke volume (SV) below normal promote the development of cardiovascular diseases.

MATERIALS AND METHODS

The study was conducted on a group of 43 patients after liver transplantation: 16 women and 27 men 0.5 to 29 years after the surgery at the Department of Transplantation Medicine, Nephrology and Internal Diseases, Institute of Transplantology, Medical University of Warsaw, Infant Jesus Clinical Hospital in Warsaw, Poland. The hemodynamic parameters were measured due to 4 electrocardiogram electrodes with the Cardiac Monitor ICON Osypka Medical.

RESULTS

Patients after liver transplantation (LTx) showed values of CO (average 5.27 L/min, standard deviation [SD] = 0.92) and stroke volume (average 67.08 mL, SD = 10.96) below normal. The average thoracic fluid content value among women is 21.81 (1/kΩ), SD = 3.28, and for men 24.04 (1/kΩ), SD = 4.75. Only 37% of patients had a body mass index with normal values, with 63% above expected values: 42% with overwise and 21% with a first stage of obesity.

CONCLUSION

The hemodynamic parameters should be controlled among patients after LTx. CO and SV below normal are predictors of a higher risk of cardiovascular diseases.

Enhanced myostatin expression and signalling promote tubulointerstitial inflammation in diabetic nephropathy

Myostatin (MSTN), a family member of the transforming growth factor (TGF)-β super family, has been detected in the tubuli of pig kidney, but its role in the human kidney is not known. In this study we observed upregulation of MSTN mRNA (~8 to 10-fold increase) both in the glomeruli and tubulointerstitium in diabetic nephropathy (DN). In DN, immunoreactive MSTN was mainly localized in the tubuli and interstitium (∼4-8 fold increase), where it colocalized in CD45⁺ cells. MSTN was also upregulated in the glomeruli and the arterial vessels. Tubulointerstitial MSTN expression was directly related to interstitial fibrosis (r = 0.54, p < 0.01). In HK-2 tubular epithelial cells, both high (30 mmol) glucose and glycated albumin upregulated MSTN mRNA and its protein (p < 0.05-0.01). MSTN-treated HK-2 cells underwent decreased proliferation, together with NF-kB activation and CCL-2 and SMAD 2,3 overexpression. In addition, MSTN induced intracellular ROS release and upregulated NADPH oxidase, effects which were mediated by ERK activation. In conclusion, our data show that MSTN is expressed in the human kidney and overexpressed in DN, mainly in the tubulointerstitial compartment. Our results also show that MSTN is a strong inducer of proximal tubule activation and suggest that MSTN overexpression contributes to kidney interstitial fibrosis in DN.

Exercise and physical activity in cirrhosis: opportunities or perils

Reduced exercise capacity and impaired physical performance are observed in nearly all patients with liver cirrhosis. Physical activity and exercise are physiological anabolic stimuli that can reverse dysregulated protein homeostasis or proteostasis and potentially increase muscle mass and contractile function in healthy subjects. Cirrhosis is a state of anabolic resistance, and unlike the beneficial responses to exercise reported in physiological states, there are few systematic studies evaluating the response to exercise in cirrhosis. Hyperammonemia is a mediator of the liver-muscle axis with net skeletal muscle ammonia uptake in cirrhosis causing signaling perturbations, mitochondrial dysfunction with decreased ATP content, modifications of contractile proteins, and impaired ribosomal function, all of which contribute to anabolic resistance in cirrhosis and have the potential to impair the beneficial responses to exercise. English language-publications in peer-reviewed journals that specifically evaluated the impact of exercise in cirrhosis were reviewed. Most studies evaluated responses to endurance exercise, and readouts included peak or maximum oxygen utilization, grip strength, and functional capacity. Endurance exercise for up to 12 wk is clinically tolerated in well-compensated cirrhosis. Data on the safety of resistance exercise are conflicting. Nutritional supplements enhance the benefits of exercise in healthy subjects but have not been evaluated in cirrhosis. Whether the beneficial physiological responses with endurance exercise and increase in muscle mass with resistance exercise that occur in healthy subjects also occur in cirrhotics is not known. Specific organ-system responses, changes in body composition, or improved long-term clinical outcomes with exercise in cirrhosis need evaluation.

Nutrition in Chronic Liver Disease: A Point-of-Care Review

Patients with chronic liver disease have a very high lifetime risk of malnourishment. It has been increasingly identified in literature that the severity of liver disease affects severity of malnutrition and vice versa. The objective of this review article is to recognize the severity of complications associated with malnutrition in patients with cirrhosis and ways to overcome these obstacles.

Assessment of Malnutrition, Sarcopenia and Frailty in Patients with Cirrhosis: Which Tools Should We Use in Clinical Practice?

Malnutrition is a common comorbidity in patients with cirrhosis. Its prognostic value is indisputable as it greatly affects the evolution of liver diseases. It has a major impact on both morbi-mortality before and after liver transplantation. Being now integrated in the definition of malnutrition and recognized as a new entity in the international classification of diseases, physicians have taken great interest in sarcopenia. Its negative consequences on the fate of patients with cirrhosis are well-demonstrated. The concept of frailty has recently been enlarged to chronic liver diseases as symptoms of impaired global physical functioning. In this article, we will discuss the definitions of malnutrition and emphasize its links with sarcopenia and frailty. We will show the relevance of frailty and sarcopenia in the course of liver diseases. The emerging role of muscle depletion on the cardiorespiratory system will also be highlighted. The importance of body composition will be demonstrated and the main tools reviewed. Finally, we adapted the definition of malnutrition to patients with cirrhosis based on the assessment of sarcopenia together with reduced food intakes.

Hepatic Encephalopathy and Nutrition Influences: A Narrative Review

Hepatic encephalopathy (HE) is a potentially reversible neurocognitive condition seen in patients with advanced liver disease. The overt form of HE has been reported in up to 45% of patients with cirrhosis. This debilitating condition is associated with increased morbidity and mortality and imposes a significant burden on the caregivers and healthcare system. After providing an overview of HE epidemiology and pathophysiology, this review focuses on the interaction of HE and frailty, nutrition requirements and recommendations in cirrhotic patients with HE, and current dietary and pharmacologic options for HE treatment.

Sarcopenia and cognitive impairment in liver cirrhosis: A viewpoint on the clinical impact of minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) represents the mildest type of hepatic encephalopathy (HE). MHE is considered as a preclinical stage of HE and is part of a wide spectrum of typical neurocognitive alterations characteristic of patients with liver cirrhosis, particularly involving the areas of attention, alertness, response inhibition, and executive functions. MHE can be detected by testing the patients’ psychometric performance, attention, working memory, psychomotor speed, and visuospatial ability, as well as by means of electrophysiological and other functional brain measures. MHE is very frequent, affecting from 20% up to 80% of patients tested, depending of the diagnostic tools used. Although subclinical, MHE is considered to be clinically relevant. In fact, MHE has been related to the patients’ falls, fitness to drive, and working ability. As a consequence, MHE affects the patients and caregivers lives by altering their quality of life and even their socioeconomic status. Recently sarcopenia, a very common condition in patients with advanced liver disease, has been shown to be strictly related to both minimal and overt HE. Aim of this review is to summarize the most recently published evidences about the emerging relationship between sarcopenia and cognitive impairment in cirrhotic patients and provide suggestions for future research.

Sarcopenia: Ammonia metabolism and hepatic encephalopathy

Sarcopenia (loss of muscle mass and/or strength) frequently complicates liver cirrhosis and adversely affects the quality of life; cirrhosis related liver decompensation and significantly decreases wait-list and post-liver transplantation survival. The main therapeutic strategies to improve or reverse sarcopenia include dietary interventions (supplemental calorie and protein intake), increased physical activity (supervised resistance and endurance exercises), hormonal therapy (testosterone), and ammonia lowering agents (L-ornithine L-aspartate, branch chain amino acids) as well as mechanistic approaches that target underlying molecular and metabolic abnormalities. Besides other factors, hyperammonemia has recently gained attention and increase sarcopenia by various mechanisms including increased expression of myostatin, increased phosphorylation of eukaryotic initiation factor 2a, cataplerosis of α ketoglutarate, mitochondrial dysfunction, increased reactive oxygen species that decrease protein synthesis and increased autophagy-mediated proteolysis. Sarcopenia contributes to frailty and increases the risk of minimal and overt hepatic encephalopathy.

Hepatic Encephalopathy and Sarcopenia: Two Faces of the Same Metabolic Alteration

Sarcopenia is an important burden in liver cirrhosis representing a negative prognostic factor for mortality. Moreover, sarcopenia is an independent predictor of complications in patients with liver cirrhosis, including Hepatic Encephalopathy (HE). An association between sarcopenia and HE in liver cirrhosis has been reported in recent studies, indeed both these complications often affect patients with advanced liver cirrhosis and may exert a synergic effect in deteriorating patients' outcome. Episodes of HE occur more often in patients with muscle depletion. The rationale for these finding is based on the role played by muscle in ammonia detoxification due to the inability of urea synthesis in the cirrhotic liver. Consequently, muscle depletion may have relevant implications in favoring hyperammonemia and HE. At the same time hyperammonemia has been found to impair muscle protein synthesis through myostatin down-regulation. From this point of view, modulation of diet and amelioration of nutritional status and muscle mass can be considered a potential goal to prevent this vicious circle and improve the cognitive impairment in cirrhotic patients.

Apparent Diffusion Coefficient Is a Novel Imaging Biomarker of Myopathic Changes in Liver Cirrhosis

Diffusion weighted imaging can provide information regarding tissue composition and can quantitatively characterize different pathological changes by means of apparent diffusion coefficient (ADC). The study comprised of 114 patients with liver cirrhosis-22 women and 92 men with a mean age of 56.5 ± 9.0 years. In all patients, the Model for End Stage-Liver Disease (MELD) score was calculated. Furthermore, 12 healthy persons (5 women, 7 men), mean age, 42.1 ± 16.2 years, were investigated as a control group. In all cases, magnetic resonance imaging of the liver/trunk was performed using different 3T scanners and diffusion weighted images were obtained with a multi-shot SE-EPI sequence. In all cases, polygonal regions of interest were manually drawn on the ADC maps along the contours of the iliopsoas and paravertebral muscles. The comparison of ADC values in groups was performed by Mann-Whitney-U tests. The association between ADC and MELD score was calculated by Spearman's rank correlation coefficient. ADC values of the skeletal musculature were statistically much higher in comparison to those in the control group: 1.85 ± 0.46 × 10^-3 mm² s^-1 vs. 1.23 ± 0.12 × 10^-3 mm² s^-1, p = 0.001. ADC values showed statistically significant correlation with the MELD score (r = 0.473, p = 0.0001). Furthermore, ADC values differed between the subgroups with different values of the MELD score. ADC values correlated slightly with lactate dehydrogenase (LDH) (r = 0.381, p = 0.0001) and tended to correlate with C-reactive protein (CRP) (r = 0.171, p = 0.07) and alanine aminotransferase (ALAT) (r = -0.167, p = 0.076). ADC can reflect muscle changes in liver cirrhosis and shows statistically significant correlation with the MELD score. Therefore, ADC can be used as an imaging biomarker of myopathic changes in liver cirrhosis.