Minimum protein requirements in liver cirrhosis determined by nitrogen balance measurements at three levels of protein intake

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.

Protein Catabolism and the Dysregulation of Energy Intake-Related Hormones May Play a Major Role in the Worsening of Malnutrition in Hospitalized Cirrhotic Patients

Malnutrition in cirrhotic patients is extremely common and has a multifactorial aetiology, whose constitutive elements have not been completely elucidated yet. Protein depletion is particularly important and an imbalance of hormones regulating hunger and satiety may be an important additive factor. The diagnosis and treatment of malnutrition are extremely important since malnutrition is associated with higher complication rates and mortality. Our observational study aimed to study protein status and energy intake-related hormone levels in a cohort of hospitalized cirrhotic patients. We enrolled 50 hospitalized and clinically stable cirrhotic patients and assessed their nutritional status with anthropometric measurements and nitrogen balance. In a subgroup of 16 patients and 10 healthy controls, circulating ghrelin and leptin levels were studied. We observed that 60% of our patients were malnourished on the basis of the mid-arm muscle circumference values; the recorded daily protein intake was tendentially insufficient (mean protein intake of 0.7 ± 0.5 g protein/kg vs. recommended intake of 1.2–1.5 g of protein/kg/die). Cirrhotic patients had lower circulating levels of both ghrelin and leptin compared to healthy controls. In conclusion, hospitalized cirrhotic patients face a catabolic state and an imbalance in hormones regulating food intake and satiety, and these elements may play a major role in the genesis and/or the worsening of malnutrition.

An Approach to the Management of Diabetes Mellitus in Cirrhosis: A Primer for the Hepatologist

The management of diabetes in cirrhosis and liver transplantation can be challenging. There is difficulty in diagnosis and monitoring of diabetes as fasting blood sugar values are low and glycosylated hemoglobin may not be a reliable marker. The challenges in the management of diabetes in cirrhosis include the likelihood of cognitive impairment, risk of hypoglycemia, altered drug metabolism, frequent renal dysfunction, risk of lactic acidosis, and associated malnutrition and sarcopenia. Moreover, calorie restriction and an attempt to lose weight in obese diabetics may be associated with a worsening of sarcopenia. Many commonly used antidiabetic drugs may be unsafe or be associated with a high risk of hypoglycemia in cirrhotics. Post-transplant diabetes is common and may be contributed by immunosuppressive medication. There is inadequate clinical data on the use of antidiabetic drugs in cirrhosis, and the management of diabetes in cirrhosis is hampered by the lack of guidelines focusing on this issue. The current review aims at addressing the practical management of diabetes by a hepatologist.

Malnourished cirrhotic patient: what should we do?

Malnutrition and sarcopenia have a high prevalence in cirrhotic patients. Frailty generally overlaps with malnutrition and sarcopenia in cirrhosis, leading to increased morbidity and mortality. Rapid nutritional screening assessment should be performed in all patients with cirrhosis, and more specific tests for sarcopenia should be performed in those at high risk. The pathogenesis of malnutrition in cirrhosis is complex and multifactorial and it is not just due to reduction in protein and calorie intake. Nutritional management in malnourished patients with cirrhosis should be undertaken by a multidisciplinary team to achieve adequate protein/calorie intake. While the role of branched-chained amino acids remains somewhat contentious in achieving a global benefit of decreasing mortality- and liver-related events, these latter and vitamin supplements, are recommended for those with advanced liver disease. Novel strategies to reverse sarcopenia such as hormone supplementation, long-term ammonia-lowering agents and myostatin antagonists, are currently under investigation. Malnutrition, sarcopenia and frailty are unique, inter-related and multidimensional problems in cirrhosis which require special attention, prompt assessment and appropriate management as they significantly impact morbidity and mortality.

Malnutrition in Patients with Liver Cirrhosis

Liver cirrhosis is an increasing public health threat worldwide. Malnutrition is a serious complication of cirrhosis and is associated with worse outcomes. With this review, we aim to describe the prevalence of malnutrition, pathophysiological mechanisms, diagnostic tools and therapeutic targets to treat malnutrition. Malnutrition is frequently underdiagnosed and occurs-depending on the screening methods used and patient populations studied-in 5-92% of patients. Decreased energy and protein intake, inflammation, malabsorption, altered nutrient metabolism, hypermetabolism, hormonal disturbances and gut microbiome dysbiosis can contribute to malnutrition. The stepwise diagnostic approach includes a rapid prescreen, the use of a specific screening tool, such as the Royal Free Hospital Nutritional Prioritizing Tool and a nutritional assessment by dieticians. General dietary measures-especially the timing of meals-oral nutritional supplements, micronutrient supplementation and the role of amino acids are discussed. In summary malnutrition in cirrhosis is common and needs more attention by health care professionals involved in the care of patients with cirrhosis. Screening and assessment for malnutrition should be carried out regularly in cirrhotic patients, ideally by a multidisciplinary team. Further research is needed to better clarify pathogenic mechanisms such as the role of the gut-liver-axis and to develop targeted therapeutic strategies.

Nutrition in Chronic Liver Disease: Consensus Statement of the Indian National Association for Study of the Liver

Malnutrition and sarcopenia are common in patients with chronic liver disease and are associated with increased risk of decompensation, infections, wait-list mortality and poorer outcomes after liver transplantation. Assessment of nutritional status and management of malnutrition are therefore essential to improve outcomes in patients with chronic liver disease. This consensus statement of the Indian National Association for Study of the Liver provides a comprehensive review of nutrition in chronic liver disease and gives recommendations for nutritional screening and treatment in specific clinical scenarios of malnutrition in cirrhosis in adults as well as children with chronic liver disease and metabolic disorders.

Malnutrition in cirrhosis: More food for thought

Malnutrition is highly prevalent in liver cirrhosis and its presence carries important prognostic implications. The clinical conditions and pathophysiological mechanisms that cause malnutrition in cirrhosis are multiple and interrelated. Anorexia and liver decompensation symptoms lead to poor dietary intake; metabolic changes characterised by elevated energy expenditure, reduced glycogen storage, an accelerated starvation response and protein catabolism result in muscle and fat wasting; and, malabsorption renders the cirrhotic patient unable to fully absorb or utilise food that has been consumed. Malnutrition is therefore a considerable challenge to manage effectively, particularly as liver disease progresses. A high energy, high protein diet is recognised as standard of care, yet patients struggle to follow this recommendation and there is limited evidence to guide malnutrition interventions in cirrhosis and liver transplantation. In this review, we seek to detail the factors which contribute to poor nutritional status in liver disease, and highlight complexities far greater than "poor appetite" or "reduced oral intake" leading to malnutrition. We also discuss management strategies to optimise nutritional status in this patient group, which target the inter-related mechanisms unique to advanced liver disease. Finally, future research requirements are suggested, to develop effective treatments for one of the most common and debilitating complications afflicting cirrhotic patients.

Sarcopenia in Cirrhosis: Looking Beyond the Skeletal Muscle Loss to See the Systemic Disease

Sarcopenia is a common complication of cirrhosis and is defined as a progressive and generalized loss of skeletal muscle mass, strength, and function. Sarcopenia is associated with poor prognosis and increased mortality. How sarcopenia and muscle wasting relate to such poor outcomes requires looking beyond the overt muscle loss and at this entity as a systemic disease that affects muscles of vital organs including cardiac and respiratory muscles. This review explores the pathophysiological pathways and mechanisms that culminate in poor outcomes associated with sarcopenia. This provides a launching pad to identify potential targets for therapeutic intervention and optimization to improve patient outcomes.

ESPEN guideline on clinical nutrition in liver disease

This update of evidence-based guidelines (GL) aims to translate current evidence and expert opinion into recommendations for multidisciplinary teams responsible for the optimal nutritional and metabolic management of adult patients with liver disease. The GL was commissioned and financially supported by ESPEN. Members of the guideline group were selected by ESPEN. We searched for meta-analyses, systematic reviews and single clinical trials based on clinical questions according to the PICO format. The evidence was evaluated and used to develop clinical recommendations implementing the SIGN method. A total of 85 recommendations were made for the nutritional and metabolic management of patients with acute liver failure, severe alcoholic steatohepatitis, non-alcoholic fatty liver disease, liver cirrhosis, liver surgery and transplantation as well as nutrition associated liver injury distinct from fatty liver disease. The recommendations are preceded by statements covering current knowledge of the underlying pathophysiology and pathobiochemistry as well as pertinent methods for the assessment of nutritional status and body composition.

EASL Clinical Practice Guidelines on nutrition in chronic liver disease

A frequent complication in liver cirrhosis is malnutrition, which is associated with the progression of liver failure, and with a higher rate of complications including infections, hepatic encephalopathy and ascites. In recent years, the rising prevalence of obesity has led to an increase in the number of cirrhosis cases related to non-alcoholic steatohepatitis. Malnutrition, obesity and sarcopenic obesity may worsen the prognosis of patients with liver cirrhosis and lower their survival. Nutritional monitoring and intervention is therefore crucial in chronic liver disease. These Clinical Practice Guidelines review the present knowledge in the field of nutrition in chronic liver disease and promote further research on this topic. Screening, assessment and principles of nutritional management are examined, with recommendations provided in specific settings such as hepatic encephalopathy, cirrhotic patients with bone disease, patients undergoing liver surgery or transplantation and critically ill cirrhotic patients.

Nutritional Considerations in Liver Disease

Malnutrition occurs in most patients with advanced liver diseases and is associated with higher rates of morbidity and mortality. In this article, the authors discuss the pathophysiology of malnutrition and methods to optimize nutrition status in liver disease and include a brief section on perioperative and postoperative nutrition.

Nutrition and the transplant candidate

Cirrhosis is the most common indication for liver transplantation (LT) worldwide. Malnutrition is present in at least two-thirds of patients with cirrhosis awaiting LT. It negatively impacts survival, quality of life, and the ability to respond to stressors, such as infection and surgery. Muscle wasting or sarcopenia is the most objective feature of chronic protein malnutrition in cirrhosis, and this condition is associated with increased morbidity and mortality before and after LT. In addition to its objectivity, muscularity assessment with cross-sectional imaging studies is a useful marker of nutritional status in LT candidates, as sarcopenia reflects a chronic decline in the general physical condition, rather than acute severity of the liver disease. Despite the high prevalence and important prognostic role, malnutrition and sarcopenia are frequently overlooked because standards for nutritional assessment are lacking and challenges such as fluid retention and obesity are prevalent. In this review, current diagnostic methods to evaluate malnutrition, including muscle abnormalities in cirrhosis, are discussed and current knowledge regarding the incidence and clinical impact of malnutrition in cirrhosis and its impact after LT are presented. Existing and potential novel therapeutic strategies for malnutrition in cirrhosis are also discussed, emphasizing the treatment of muscle wasting in the LT candidate in an effort to improve survival while waiting for LT and to reduce morbidity and mortality after LT.Liver Transplantation 23 1451-1464 2017 AASLD.

Ascites, refractory ascites and hyponatremia in cirrhosis

Ascites is the most common complication related to cirrhosis and is associated with increased morbidity and mortality. Ascites is a consequence of the loss of compensatory mechanisms to maintain the overall effective arterial blood volume due to worsening splanchnic arterial vasodilation as a result of clinically significant portal hypertension. In order to maintain effective arterial blood volume, vasoconstrictor and antinatriuretic pathways are activated, which increase overall sodium and fluid retention. As a result of progressive splanchnic arterial vasodilation, intestinal capillary pressure increases and results in the formation of protein-poor fluid within the abdominal cavity due to increased capillary permeability from the hepatic sinusoidal hypertension. In some patients, the fluid can translocate across diaphragmatic fenestrations into the pleural space, leading to hepatic hydrothorax. In addition, infectious complications such as spontaneous bacterial peritonitis can occur. Eventually, as the liver disease progresses related to higher portal pressures, loss of a compensatory cardiac output and further splanchnic vasodilation, kidney function becomes compromised from worsening renal vasoconstriction as well as the development of impaired solute-free water excretion and severe sodium retention. These mechanisms then translate into significant clinical complications, such as refractory ascites, hepatorenal syndrome and hyponatremia, and all are linked to increased short-term mortality. Currently, liver transplantation is the only curative option for this spectrum of clinical manifestations but ongoing research has led to further insight on alternative approaches. This review will further explore the current understanding on the pathophysiology and management of ascites as well as expand on two advanced clinical consequences of advanced liver disease, refractory ascites and hyponatremia.

Management of Parenteral Nutrition in Hospitalized Adult Patients [Formula: see text]

Despite the high prevalence of malnutrition in adult hospitalized patients, surveys continue to report that many clinicians are undertrained in clinical nutrition, making targeted nutrition education for clinicians essential for best patient care. Clinical practice models also continue to evolve, with more disciplines prescribing parenteral nutrition (PN) or managing the cases of patients who are receiving it, further adding to the need for proficiency in general PN skills. This tutorial focuses on the daily management of adult hospitalized patients already receiving PN and reviews the following topics: (1) PN basics, including the determination of energy and volume requirements; (2) PN macronutrient content (protein, dextrose, and intravenous fat emulsion); (3) PN micronutrient content (electrolytes, minerals, vitamins, and trace elements); (4) alteration of PN for special situations, such as obesity, hyperglycemia, hypertriglyceridemia, refeeding, and hepatic/renal disease; (5) daily monitoring and adjustment of PN formula; and (6) PN-related complications (PN-associated liver disease and catheter-related complications).

Role of Nutrition and Muscle in Cirrhosis

OPINION STATEMENT

Most widely recognized complications in cirrhotic patients include ascites, hepatic encephalopathy, variceal bleeding, kidney dysfunction, and hepatocellular carcinoma; however, malnutrition and muscle wasting (sarcopenia) constitute common complications which negatively impact survival, quality of life, and response to stressors, such as infection and surgery in patients with cirrhosis. Despite the important role that malnutrition and sarcopenia play in the prognosis of patients with cirrhosis, they are frequently overlooked, in part because nutritional assessment can be a difficult task in patients with cirrhosis due to fluid retention and/or overweight. Moreover, patients with cirrhosis may develop simultaneous loss of skeletal muscle and gain of adipose tissue, culminating in the condition of "sarcopenic obesity." In addition, muscle depletion is characterized by both a reduction in muscle size and increased proportion of intermuscular and intramuscular fat-denominated "myosteatosis." Sarcopenia in cirrhotic patients has been associated with increased mortality, sepsis complications, hyperammonemia, overt hepatic encephalopathy, and increased length of stay after liver transplantation. Muscularity assessment with cross-sectional imaging studies has become an attractive index of nutritional status evaluation in cirrhosis, as sarcopenia reflects a chronic detriment in general physical condition, rather than acute severity of the liver disease. In this review, we discuss the current diagnostic methods to evaluate malnutrition and muscle abnormalities in cirrhosis and also analyze the current knowledge regarding incidence and clinical impact of malnutrition and muscle abnormalities in cirrhosis and their impact after liver transplantation. We also discuss existing and potential novel therapeutic strategies for malnutrition in cirrhosis, emphasizing the recognition of sarcopenia in cirrhosis in an effort to improve survival and reduce morbidity related to cirrhosis. Finally, we analyze new studies including sarcopenia with the MELD score that seems to allow better prediction of mortality among cirrhotic patients waiting for liver transplantation.

Protein restriction in hepatic encephalopathy is appropriate for selected patients: a point of view

Since the late nineteenth century, protein restriction has been shown to improve hepatic encephalopathy. However, malnutrition has been described in up to 60 % of cirrhotic patients and is associated with increased mortality. Furthermore, emerging clinical evidence has revealed that a large proportion of cirrhotic patients may tolerate normal protein intake. However, approximately one third of cirrhotic patients with hepatic encephalopathy may need a short course of protein restriction, in addition to maximum medical therapy, to ameliorate the clinical course of their hepatic encephalopathy. For patients with chronic hepatic encephalopathy who are protein-sensitive, modifying their sources of nitrogen by using more vegetable protein, less animal protein, and branched-chain amino acids may improve their encephalopathy without further loss of lean body mass. In conclusion, among cirrhotics with hepatic encephalopathy, modulation of normal protein intake must take into account the patient's hepatic reserve, severity of hepatic encephalopathy, and current nutritional status.

Insufficient Protein Intake Is Associated With Increased Mortality in 630 Patients With Cirrhosis Awaiting Liver Transplantation

BACKGROUND

For patients awaiting liver transplantation, we aimed to determine the prevalence and predictors of insufficient protein intake as well as to determine whether very low protein intake was an independent predictor of malnutrition and mortality.

MATERIALS AND METHODS

Adults with cirrhosis who were activated on our local liver transplant waiting list between January 2000 and October 2009 were included. Estimated protein intake was derived from dietary records. Patients with incomplete dietary records were excluded. Multivariable logistic regression and competing risk analysis were used.

RESULTS

Of 742 potential patients, 112 were excluded due to insufficient data, leaving 630 patients for evaluation. Mean protein intake was 1.0 ± 0.36 g/kg/d and only 24% of patients met the expert consensus recommended threshold of > 1.2 g/kg of protein per day. Very low protein intake (< 0.8 g/kg/d) was associated with worse liver disease severity (as measured by Child-Pugh or MELD). Protein intake below 0.8 g/kg/d was an independent predictor both of malnutrition as measured by the subjective global assessment (adjusted odds ratio [95% confidence interval (CI)]: 2.0 [1.3-3.0]) and of transplant waiting list mortality (adjusted hazard ratio [95% CI]: 1.8 [1.2-2.7]).

CONCLUSION

In this large cohort of liver transplant waitlisted patients, very low protein intake was prevalent and independently associated with malnutrition and mortality. Unlike many other prognostic factors, protein intake is potentially modifiable. Prospective studies are warranted to evaluate the effect of targeted protein repletion on clinically relevant outcomes such as muscle mass, muscle function, immune function, and mortality.

Contributions of microdialysis to new alternative therapeutics for hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis, of largely reversible impairment of brain function occurring in patients with acute or chronic liver failure or when the liver is bypassed by portosystemic shunts. The mechanisms causing this brain dysfunction are still largely unclear. The need to avoid complications caused by late diagnosis has attracted interest to understand the mechanisms underlying neuronal damage in order to find markers that will allow timely diagnosis and to propose new therapeutic alternatives to improve the care of patients. One of the experimental approaches to study HE is microdialysis; this technique allows evaluation of different chemical substances in several organs through the recollection of samples in specific places by semi-permeable membranes. In this review we will discuss the contributions of microdialysis in the understanding of the physiological alterations in human hepatic encephalopathy and experimental models and the studies to find novel alternative therapies for this disease.

Consilience in sarcopenia of cirrhosis

Cirrhosis is the consequence of progression of many forms of necro-inflammatory disorders of the liver with hepatic fibrosis, hepatocellular dysfunction, and vascular remodeling. Reversing the primary hepatic disorder, liver transplantation, and controlling the complications are the major management goals. Since the former options are not available to the majority of cirrhotics, treating complications remains the mainstay of therapy. Sarcopenia and/or cachexia is the most common complication and adversely affects survival, quality of life, development of other complications of cirrhosis, and outcome after liver transplantation. With the increase in number of cirrhotic patients with hepatitis C and nonalcoholic fatty liver disease, the number of patients waiting for a liver transplantation is likely to continue to increase above the currently estimated 72.3/100,000 population. One of the critical clinical questions is to determine if we can treat sarcopenia of cirrhosis without transplantation. No effective therapies exist to treat sarcopenia because the mechanism(s) of sarcopenia in cirrhosis is as yet unknown. The reasons for this include the predominantly descriptive studies to date and the advances in our understanding of skeletal muscle biology and molecular regulation of atrophy and hypertrophy not being translated into the clinical practice of hepatology. Satellite cell biology, muscle autophagy and apoptosis, and molecular signaling abnormalities in the skeletal muscle of cirrhotics are also not known. Aging of the cirrhotic and transplanted population, use of mTOR inhibitors, and the lack of definitive outcome measures to define sarcopenia and cachexia in this population add to the difficulty in increasing our understanding of hepatic sarcopenia/cachexia and developing treatment options. Recent data on the role of myostatin, AMP kinase, impaired mTOR signaling resulting in anabolic resistance in animal models, and the rapidly developing field of nutriceuticals as signaling molecules need to be evaluated in human cirrhotics. Finally, the benefits of exercise reported in other disease states with sarcopenia may not be safe in cirrhotics due to the risk of gastrointestinal variceal bleeding due to an increase in portal pressure. This article focuses on the problems facing both muscle biologists and hepatologists in developing a comprehensive approach to sarcopenia in cirrhosis.

Malnutrition in cirrhosis: contribution and consequences of sarcopenia on metabolic and clinical responses

Malnutrition is the most common, reversible complication of cirrhosis that adversely affects survival, response to other complications, and quality of life. Sarcopenia, or loss of skeletal muscle mass, and loss of adipose tissue and altered substrate use as a source of energy are the 2 major components of malnutrition in cirrhosis. Current therapies include high protein supplementation especially as a late evening snack. Exercise protocols have the potential of aggravating hyperammonemia and portal hypertension. Recent advances in understanding the molecular regulation of muscle mass has helped identify potential novel therapeutic targets including myostatin antagonists, and mTOR resistance.

Hepatic encephalopathy: an updated approach from pathogenesis to treatment

One of the most serious complications of chronic or fulminant liver failure is hepatic encephalopathy (HE), associated most commonly with cirrhosis. In the presence of chronic liver disease, HE is a sign of decompensation, while in fulminant liver failure its development represents a worrying sign and usually indicates that transplantation will be required. Despite the significance of HE in the course of liver disease, the progress in development of new therapeutic options has been unremarkable over the last 20 years. An up-to-date review regarding HE, including both research and review articles. HE is a serious and progressive, but potentially reversible, disorder with a wide spectrum of neuropsychiatric abnormalities and motor disturbances that ranges from mild alteration of cognitive and motor function to coma and death. Although a clear pathogenesis is yet to be determined, elevated ammonia in serum and the central nervous system is the mainstay for pathogenesis and treatment of HE. Management includes early diagnosis and prompt treatment of precipitating factors. Clinical trials and extensive clinical experience have established the efficacy of diverse substances in HE treatment. Novel therapies with clinical promise include: L-ornithine L-aspartate, sodium benzoate, phenylacetate, AST-120, and the molecular adsorbent recirculating system. Eventually, liver transplantation is often the most successful long-term therapy for HE.

Adjuvant nutrition management of patients with liver failure, including transplant

This article reviews nutrition support in patients with liver disease, including those who are undergoing surgery or liver transplant. The topics covered include the multifactorial etiology of malnutrition, nutritional assessment, and nutritional therapy. Recommendations for use of both enteral and parenteral nutrition are given in patients with alcoholic hepatitis, cirrhosis, and acute liver failure and in patients undergoing surgery or liver transplant.

Malnutrition and nutrition support in patients with liver disease

Liver disease, especially alcohol related, is increasingly common and is often accompanied by malnutrition as a result of reduced intake, absorption, processing and storage of nutrients. An increase or alteration in metabolic demands also occurs and some patients have high nutrient losses. Malnutrition in all forms of liver disease is associated with higher rates of mortality and morbidity but it is often under recognised and under treated despite the fact that appropriate treatment can improve outcomes. In this review, the causes, consequences and assessment of nutritional status in patients with liver disease are examined, and an approach to best treatment is proposed.

Hepatology - Guidelines on Parenteral Nutrition, Chapter 16

Parenteral nutrition (PN) is indicated in alcoholic steatohepatitis (ASH) and in cirrhotic patients with moderate or severe malnutrition. PN should be started immediately when sufficientl oral or enteral feeding is not possible. ASH and cirrhosis patients who can be sufficiently fed either orally or enterally, but who have to abstain from food over a period of more than 12 hours (including nocturnal fasting) should receive basal glucose infusion (2–3 g/kg/d). Total PN is required if such fasting periods last longer than 72 h. PN in patients with higher-grade hepatic encephalopathy (HE); particularly in HE IV° with malfunction of swallowing and cough reflexes, and unprotected airways. Cirrhotic patients or patients after liver transplantation should receive early postoperative PN after surgery if they cannot be sufficiently rally or enterally nourished. No recommendation can be made on donor or organ conditioning by parenteral administration of glutamine and arginine, aiming at minimising ischemia/reperfusion damage. In acute liver failure artificial nutrition should be considered irrespective of the nutritional state and should be commenced when oral nutrition cannot be restarted within 5 to 7 days. Whenever feasible, enteral nutrition should be administered via a nasoduodenal feeding tube.

ESPEN Guidelines on Parenteral Nutrition: hepatology

Parenteral nutrition (PN) offers the possibility to increase or to ensure nutrient intake in patients, in whom sufficient nutrition by oral or enteral alone is insufficient or impossible. Complementary to the ESPEN guideline on enteral nutrition of liver disease (LD) patients the present guideline is intended to give evidence-based recommendations for the use of PN in LD. For this purpose three paradigm conditions of LD were chosen: alcoholic steatohepatitis (ASH), liver cirrhosis and acute liver failure. The guideline was developed by an interdisciplinary expert group in accordance with officially accepted standards and is based on all relevant publications since 1985. The guideline was presented on the ESPEN website and visitors' criticism and suggestions were welcome and included in the final revision. PN improves nutritional state and liver function in malnourished patients with ASH. PN is safe and improves mental state in patients with cirrhosis and severe HE. Perioperative (including liver transplantation) PN is safe and reduces the rate of complications. In acute liver failure PN is a safe second-line option to adequately feed patients in whom enteral nutrition is insufficient or impossible.

Role of branched-chain amino acids in management of cirrhosis and hepatocellular carcinoma

Altered protein and energy metabolism is a hallmark of chronic liver disease, characterized by decreased plasma branched-chain amino acids (BCAA) and increased plasma aromatic amino acids (AAA). Overwhelming evidence has indicated that the incidence of complications of chronic liver disease increases with malnutrition. Hence nutritional management in patients with chronic liver disease must receive high priority. The use of BCAA supplementation has been a controversial subject. This review summarizes published results of BCAA supplementation as a nutritional therapy for patients with cirrhosis and hepatocellular carcinoma (HCC). On balance, it would be appropriate to conclude that BCAA are associated with decreased frequency of complications of cirrhosis and improved nutritional status when prescribed as a maintenance therapy for patients with cirrhosis. More studies are, however, required to identify those who might benefit most from BCAA supplementation.

The role of nutrition in hepatic encephalopathy

PURPOSE OF REVIEW

Protein-calorie malnutrition may be observed in all clinical stages of liver disease. Nutritional management in these patients is imperative. It is crucial that protein intake is not restricted ad hoc. Administration of vegetable proteins for patients who cannot tolerate standard proteins and, if necessary, branched-chain amino acid-enriched formulae can be an option to these patients. This issue, however, remains controversial.

RECENT FINDINGS

This study is an update on the nutritional management of hepatic encephalopathy based on several studies of the last decades, involving dietary protein intake and branched-chain amino acid supplementation.

SUMMARY

Malnutrition is a common complication of liver disease and it adversely affects patient outcome. Inadequate dietary protein intake has a very deleterious effect on hepatic encephalopathy, nutritional status, and clinical outcome in these patients and must be avoided. The administration of branched-chain amino acids stimulates hepatic protein synthesis, reduces postinjury catabolism and therefore improves nutritional status. Conflicting results in various different trials, however, exist, and this issue remains unclear.

Role of branched-chain amino acids in liver disease: the evidence for and against

PURPOSE OF REVIEW

There is ample evidence that patients with liver disease have an ongoing energy and protein catabolism. Nutritional management in these patients must receive high priority. The administration of branched-chain amino acids to patients with liver disease has been a controversial subject. This review is an update on the data available from various studies involving branched-chain amino acids supplementation in patients with chronic liver disease and associated complications.

RECENT FINDINGS

This review summarizes the results of nutritional interventions involving branched-chain amino acids supplementation carried out in different centres around the world. It is interesting to note that no toxic effects of branched-chain amino acids supplementation have been reported in any of these trials.

SUMMARY

Administration of branched-chain amino acids stimulates hepatic protein synthesis in patients with chronic liver disease and this could contribute significantly to improving their nutritional status, and result in a better quality of life. The beneficial role of branched-chain amino acids supplementation in patients with chronic hepatic encephalopathy has been clearly documented in some studies but the exact mechanism of action is still not clear.

Nutrition in end stage liver disease

This chapter will focus on studies within the last 5 years of nutrition in end stage liver disease, but earlier studies illustrating the present state of affairs will also be mentioned. The first part will focus on descriptive epidemiological studies that help to set the scene for the intervention studies, which will be described in the second part. Each part will discuss liver cirrhosis, acute liver failure and liver transplantation separately. The aim is to provide the reader with sufficient background for the decision in clinical practice about when to see nutrition support as an important part of treatment of the patient.

Effects of oral branched-chain amino acid granules on event-free survival in patients with liver cirrhosis

BACKGROUND & AIMS

Nutritional intervention with branched-chain amino acid (BCAA) is reported to increase serum albumin concentration in patients with decompensated cirrhosis. However, a definite conclusion on whether it can improve patients' survival has not yet been reached. The present study aimed to test possibilities of improving survival of patients with decompensated cirrhosis by using a BCAA preparation that is suitable for long-term oral administration.

METHODS

A multicenter, randomized, and nutrient intake-controlled trial on the comparative effects of BCAA orally administered at 12 g/day for 2 years versus diet therapy with defined daily food intake (1.0-1.4 g protein kg(-1) day(-1) including BCAA preparation and 25-35 kcal kg(-1) day(-1)) was conducted in 646 patients with decompensated cirrhosis. The primary end point was a composite of death by any cause, development of liver cancer, rupture of esophageal varices, or progress of hepatic failure (event-free survival). The secondary end points were serum albumin concentration and health-related quality of life (QOL) measured by Short Form-36 questionnaire.

RESULTS

The incidence of events comprising the primary end point significantly decreased in the BCAA group as compared with the diet group (hazard ratio, 0.67; 95% confidence interval, 0.49-0.93; P = .015; median observation period, 445 days). Serum albumin concentration increased significantly in the BCAA group as compared with the diet group (P = .018). The "general health perception" domain in Short Form-36 measures was also improved (P = .003). Patients' adherence to the prescription was favorable.

CONCLUSIONS

Oral supplementation with a BCAA preparation that can be administered for a long period improves event-free survival, serum albumin concentration, and QOL in patients with decompensated cirrhosis with an adequate daily food intake.

Branched-chain amino acid supplementation in patients with liver diseases

Because of their peculiar role in whole-body nitrogen metabolism and the competitive action on amino acid transport across the blood-brain barrier, branched-chain amino acids (BCAAs) have been extensively used in subjects with liver disease to preserve or to restore muscle mass and to improve hepatic encephalopathy. There are no data regarding safe limits of BCAA administration; the results appear to be better when BCAA-enriched formulas or BCAA-supplemented diets are preferred to pure BCAA formulas. Improved nitrogen retention might ameliorate the nutritional status, a prognostic index of long-term survival in cirrhosis and of short-term survival in patients undergoing surgical procedures. The effects on nutrition and ultimately on prognosis of patients with advanced cirrhosis were confirmed in a large multicenter, long-term trial where oral BCAA supplements were compared with equicaloric or equinitrogenous-equicaloric supplements (maltodextrin or lactoalbumin). Similarly, BCAA treatment improved the prognosis of patients with hepatocellular carcinoma, treated by surgical resection or chemoembolization, and of liver transplant patients. The mechanism(s) for the beneficial effects of BCAAs might be mediated by their stimulating activity on hepatocyte growth factor, favoring liver regeneration. The debate regarding the potential effectiveness of BCAAs dates back to the early 1980s. The number of patients who cannot tolerate dietary proteins in amounts sufficient to meet the higher catabolism of advanced liver disease is probably low, but BCAAs remain the sole treatment of proved efficacy in this specific setting.

Normal protein diet for episodic hepatic encephalopathy: results of a randomized study

BACKGROUND/AIMS

Protein-restricted diets are usually prescribed for cirrhotic patients with hepatic encephalopathy. However, protein restriction may worsen the nutritional status without resulting in an improvement of hepatic encephalopathy. We designed a study to assess the effects of the amount of protein in the diet on the evolution of episodic hepatic encephalopathy.

METHODS

Cirrhotics admitted to the hospital because of an episode of encephalopathy (n=30) were randomized to receive a low-protein diet with progressive increments or a normal protein diet for 14 days, in addition to standard measures to treat hepatic encephalopathy. Protein synthesis and breakdown were studied at day 2 and day 14 with the glycine-N(15) infusion method.

RESULTS

The outcome of hepatic encephalopathy was not significantly different between both groups of treatment. Protein synthesis was similar for low and normal protein diet, but those of the low-protein diet group showed higher protein breakdown.

CONCLUSIONS

Diets with a normal content of protein, which are metabolically more adequate, can be administered safely to cirrhotic patients with episodic hepatic encephalopathy. Restriction of the content of protein of the diet does not appear to have any beneficial effect for cirrhotic patients during an episode of encephalopathy.

Role of circulating neurotoxins in the pathogenesis of hepatic encephalopathy: potential for improvement following their removal by liver assist devices

Both acute and chronic liver failure result in impaired cerebral function known as hepatic encephalopathy (HE). Evidence suggests that HE is the consequence of the accumulation in brain of neurotoxic and/or neuroactive substance including ammonia, manganese, aromatic amino acids, mercaptans, phenols, short-chain fatty acids, bilirubin and a variety of neuroactive medications prescribed as sedatives to patients with liver failure. Brain ammonia concentrations may attain levels in excess of 2 mm, concentrations which are known to adversely affect both excitatory and inhibitory neurotransmission as well as brain energy metabolism. Manganese exerts toxic effects on dopaminergic neurones. Prevention and treatment of HE continues to rely heavily on the reduction of circulating ammonia either by reduction of gut production using lactulose or antibiotics or by increasing its metabolism using L-ornithine-L-aspartate. No specific therapies have so far been designed to reduce circulating concentrations of other toxins. Liver assist devices offer a potential new approach to the reduction of circulating neurotoxins generated in liver failure. In this regard, the Molecular Adsorbents Recirculating System (MARS) appears to offer distinct advantages over hepatocyte-based systems.

Branched-chain amino acids as a protein- and energy-source in liver cirrhosis

Protein-energy malnutrition (PEM) is a common manifestation in cirrhotic patients with reported incidences as high as 65-90%. PEM affects largely the patients' quality of life and survival. Thus, diagnosis of and intervention for PEM is important in the clinical management of liver cirrhosis. Supplementation with branched-chain amino acids (BCAA) is indicated to improve protein malnutrition. As an intervention for energy malnutrition, frequent meal or late evening snack has been recently recommended. Plasma amino acid analysis characterizes the patients with liver cirrhosis to have decreased BCAA. Such reduction of BCAA is explained by enhanced consumption of BCAA for ammonia detoxication and for energy generation. Supplementation with BCAA raises in vitro the synthesis and secretion of albumin by cultured rat hepatocytes without affecting albumin mRNA expression. BCAA recover the impaired turnover kinetics of albumin both in rat cirrhotic model and in cirrhotic patients. Longer-term supplementation with BCAA raises plasma albumin, benefits quality of life issues, and finally improves survival in liver cirrhosis. Recent interests focused on the timing of administration of BCAA, since daytime BCAA are usually consumed by energy generation for physical exercise of skeletal muscles. Nocturnal BCAA seem to be more favorable as a source of protein synthesis by giving higher nitrogen balance. This minireview focuses on the basic and clinical aspects of BCAA as a pharmaco-nutritional source to control PEM in liver cirrhosis.

Complications of cirrhosis III. Hepatic encephalopathy

Hepatic encephalopathy (HE) is a major neuropsychiatric complication of cirrhosis. HE develops slowly in cirrhotic patients, starting with altered sleep patterns and eventually progressing through asterixis to stupor and coma. Precipitating factors are common and include an oral protein load, gastrointestinal bleeding and the use of sedatives. HE is common following transjugular intrahepatic portosystemic stent shunts (TIPS). Neuropathologically, HE in cirrhotic patients is characterized by astrocytic (rather than neuronal) changes known as Alzheimer type II astrocytosis and in altered expression of key astrocytic proteins. Magnetic resonance imaging in cirrhotic patients reveals bilateral signal hyperintensities particularly in globus pallidus on T1-weighted imaging, a phenomenon which may result from manganese deposition. Proton (1H) magnetic resonance spectroscopy shows increases in the glutamine resonance in brain, a finding which confirms previous biochemical studies and results no doubt from increased brain ammonia removal (glutamine synthesis). Additional evidence for increased brain ammonia uptake and removal in cirrhotic patients is provided by studies using positron emission tomography and 13NH3. Recent molecular biological studies demonstrate increased expression of genes coding for neurotransmitter-related proteins in chronic liver failure. Such genes include monoamine oxidase (MAO-A isoform), the peripheral-type benzodiazepine receptor and nitric oxide synthase (nNOS isoform). Activation of these systems has the potential to lead to alterations of monoamine and amino acid neurotransmitter function as well as modified cerebral perfusion in chronic liver failure. Prevention and treatment of HE in cirrhotic patients continues to rely on ammonia-lowering strategies which include assessment of dietary protein intake and the use of lactulose, neomycin, sodium benzoate and L-ornithine-aspartate. The benzodiazepine receptor antagonist flumazenil may be effective in certain cases. A more widespread use of central nervous system-acting drugs awaits a more complete understanding of the precise neurotransmitter systems involved in the pathogenesis of HE in chronic liver failure.

Resting energy expenditure should be measured in patients with cirrhosis, not predicted

Measurements of resting energy expenditure (REE) can be used to determine energy requirements. Prediction formulae can be used to estimate REE but have not been validated in cirrhotic patients. REE was measured, by indirect calorimetry, in 100 cirrhotic patients and 41 comparable healthy volunteers, and the results compared with estimates predicted using the Harris-Benedict, Schofield, Mifflin, Cunningham, and Owen formulae, and the disease-specific Müller formula. The mean (+/- 1 SD) measured REE in the healthy volunteers (1,590 +/- 306 kcal/24 h) was significantly greater than the mean Harris-Benedict, Mifflin, Cunningham, and Owen predictions but comparable with the mean Schofield prediction; individual predicted values varied widely from measured values (95% limits of agreement, -460 to +424 kcal). The mean measured REE in the cirrhotic patients was significantly greater than in the healthy volunteers (23.2 +/- 3. 8 cf 21.9 +/- 2.9 kcal/kg/24 h; P <.05). The mean measured REE in the cirrhotic patients (1,660 +/- 337 kcal/24 h) was significantly different from mean predicted values (Harris-Benedict, 1,532 +/- 252 kcal/24 h, P <.0001; Schofield, 1,575 +/- 254 kcal/24 h, P <.0005; Mifflin, 1,460 +/- 254 kcal/24 h, P <.0001; Cunningham, 1,713 +/- 252 kcal/24 h, P <.05; Owen, 1,521 +/- 281 kcal/24 h, P <.0001; Müller, 1,783 +/- 204 kcal/24 h, P <.0001); individual predicted values varied widely from measured values (95% limits of agreement, -632 to +573 kcal). Simple regression analysis showed that fat-free mass (FFM) was the strongest predictor of measured REE in the cirrhotic patients, accounting for 52% of the variation observed. However, a population-specific prediction equation, derived using stepwise regression analysis, which incorporated FFM, age, and Pugh's score, accounted for only 61% of the observed variation in measured REE. REE should, therefore, be measured in cirrhotic patients, not predicted.

Nutritional support in hepatic encephalopathy

Hepatic encephalopathy (HE) is a syndrome of global cerebral dysfunction resulting from underlying liver disease or portal-systemic shunting. HE can present as one of four syndromes, depending on the rapidity of onset of hepatic failure and the presence or absence of preexisting liver disease. The precise pathogenesis is unknown but likely involves impaired hepatic detoxification of ammonia as well as alterations in brain transport and metabolism of amino acids and amines. The etiology of malnutrition in hepatic failure is multifactorial. Nutritional deficits may be clinically manifest as marasmus or kwashiorkor, or both. Nutritional support in HE is directed toward reducing morbidity related to underlying malnutrition and concurrent disease. However, reaching nutritional goals is often complicated by protein and carbohydrate intolerance. The use of protein restriction in HE is controversial. Modified formulas that are supplemented in branched chain amino acids may be of value in patients who exhibit protein intolerance with standard feeding solutions or in patients who present with advanced degrees of encephalopathy.

Effects of xylitol on urea synthesis in patients with cirrhosis of the liver

BACKGROUND

In individuals with cirrhosis the normal inhibiting effect of glucose on urea synthesis is lost, probably because of very high concentrations of glucagon. In agreement, glucose does not prevent the inducing effect of glucagon on urea synthesis in normal humans. In contrast, the sugar alcohol, xylitol, prevents the increasing effect of glucagon in normal humans. We, therefore, examined the effect of xylitol on urea synthesis in individuals with cirrhosis and hyperglucagonemia.

METHODS

Urea synthesis, calculated as urinary excretion rate corrected for accumulation in total body water and intestinal loss, was measured during infusion of alanine (2 mmol/[h x kg body wt]) and during infusion of alanine superimposed on infusion of xylitol (0.12 g/[h x kg body wt]) in 8 individuals with biopsy-proven alcoholic cirrhosis. The functional hepatic nitrogen clearance (FHNC), ie, urea synthesis expressed independent of changes in plasma amino acid concentration, was calculated as the slope of the linear relation between the urea synthesis rate and the plasma amino acid concentration.

RESULTS

All individuals had elevated basal plasma glucagon concentration (261 +/- 61 ng/L; mean +/- SEM) and a markedly increased response to alanine infusion (1037 +/- 226 ng/L). This was not changed by xylitol. Neither the basal urea synthesis rate (13.2 +/- 2.5 mmol/h) nor the alanine-stimulated urea synthesis rate (76.8 +/- 3.64 mmol/h) was changed by xylitol. FHNC during the infusion of alanine alone was 10.5 +/- 0.9 L/h and did not change during the concomitant infusion of xylitol (10.1 +/- 1.1 L/h).

CONCLUSIONS

Xylitol reduces neither urea synthesis nor FHNC. The data do not support an important role of xylitol as a nitrogen-sparing agent in cirrhosis.

Oral supplementation with branched-chain amino acids improves survival rate of rats with carbon tetrachloride-induced liver cirrhosis

We investigated whether supplementation with branched-chain amino acids (BCAA) improves survival of rats with carbon tetrachloride (CCl4) -induced cirrhosis. Liver cirrhosis was induced in 40 male Sprague-Dawley rats by administering CCl4 for 15 weeks. Twenty rats each were then assigned to the control and BCAA group and fed a casein diet or a BCAA-supplemented casein diet, respectively, for an additional 17 weeks with repeated injections of CCl4. No significant difference occurred in either mean energy or nitrogen intake or in body or liver weight between the two groups. BCAA-supplementation significantly preserved plasma albumin concentrations (P < 0.05) and inhibited significantly the occurrence of ascites and hyperammonemia (P < 0.05). The survival rate was significantly higher in the BCAA group (P=0.03), while no significant difference was found in liver histology between the groups. These results suggest that BCAA improved survival of rats with CCl4-induced cirrhosis by preventing hypoalbuminemia and hyperammonemia without directly reducing hepatic necrosis and fibrosis.

Portal systemic encephalopathy

The goal of this article is to update the status of Portal systemic encephalopathy (PSE) in the light of new data. First, PSE is the context of other types of hepatic encephalopathy. Subsequently, current views of the pathogenesis of the disorder are discussed, followed by an analysis of therapeutic options. Diagnosis will not be considered, as no major new developments have recently been documented in this area.

Effect of long-term refeeding on protein metabolism in patients with cirrhosis of the liver

Patients with cirrhosis of the liver require an increased amount of protein to achieve N balance. However, the utilization of protein with increased protein intake, i.e. the slope from regression analysis of N balance v. intake, is highly efficient (Nielsen et al. 1995). In the present study, protein requirement and protein utilization were investigated further by measuring protein synthesis and degradation. In two separate studies, five or six patients with cirrhosis of the liver were refed on a balanced diet for an average of 2 or 4 weeks. Protein and energy intakes were doubled in both studies. Initial and final whole-body protein metabolism was measured in the fed state by primed continuous [15N]glycine infusion. Refeeding caused a statistically significant increase of about 30% in protein synthesis in both studies while protein degradation was only slightly affected. The increase in protein synthesis was associated with significant increases in plasma concentrations of total amino acids (25%), leucine (58%), isoleucine (82%), valine (72%), proline (48%) and triiodothyronine (27%) while insulin, growth hormone, insulin-like growth factor (IGF)-I and IGF-binding protein-3 were not changed significantly. The results indicate that the efficient protein utilization is due to increased protein synthesis, rather than decreased protein degradation, and suggest that increases in plasma amino acids may be responsible for the increased protein synthesis. A comparison of the patients who had a normal protein requirement with the patients who had an increased protein requirement suggests that the increased protein requirement is due to a primary increase in protein degradation. It is speculated that this is due to low levels of IGF-I secondary to impaired liver function, since initial plasma concentration of IGF-I was about 25% of control values and remained low during refeeding.