Nutritional aspects of chronic liver disease

Body composition, muscle function, and energy expenditure in patients with liver cirrhosis: a comprehensive study

BACKGROUND

Data describing the nutritional status of patients with liver cirrhosis of diverse origin, as assessed by direct body-composition methods, are limited.

OBJECTIVE

We sought to provide a comprehensive assessment of nutritional status and metabolic activity in patients with liver cirrhosis by using the most accurate direct methods available.

DESIGN

Two hundred sixty-eight patients (179 M, 89 F; x +/- SEM age: 50.1 +/- 0.6 y) with liver cirrhosis underwent measurements of total body protein by neutron activation analysis, of total body fat and bone mineral by dual-energy X-ray absorptiometry, of resting energy expenditure by indirect calorimetry, of grip strength by dynamometry, and of respiratory muscle strength by using a pressure transducer. Dietary intakes of energy and protein were assessed and indexed to resting energy expenditure and energy intake, respectively.

RESULTS

Significant protein depletion, seen in 51% of patients, was significantly (P<0.0001) more prevalent in men (63%) than in women (28%). This sex difference occurred irrespective of disease severity or origin. The prevalence of protein depletion increased significantly (P<0.0001) with disease severity. Protein depletion was associated with decreased muscle function but not with lower energy and protein intake. Energy intake was significantly (P=0.002) higher in men than in women, whereas protein intakes did not differ significantly (P=0.12). Hypermetabolism, seen in 15% of patients, was not associated with sex, origin or severity of disease, protein depletion, ascites, or presence of tumor.

CONCLUSIONS

Poor nutritional status with protein depletion and reduced muscle function was a common finding, particularly in men, and was not related to the presence of hypermetabolism or reduced energy and protein intakes. The greater conservation of protein stores in women than in men warrants further investigation.

Nutritional aspects of liver disease and transplantation

In the past year, some relevant papers related to the diagnosis of malnutrition and its pathogenesis in cirrhosis have been published. The value of anthropometrics in the nutritional assessment of end-stage cirrhotic patients has been reinforced. Also, the role of bioelectrical impedance analysis in these patients has been redefined. Several papers have investigated the relationship between leptin and malnutrition in chronic liver disease, particularly the role of alcoholism in hyperleptinaemia, and the importance of protein-bound leptin in these patients. In other papers, the impact of both undernutrition and obesity on the outcome of liver transplantation has been investigated. Two randomized, controlled trials on enteral nutrition in liver disease have been published in this period. One of them deals with a clinical situation (i.e. severe alcoholic hepatitis) associated with a high mortality rate, whereas the second is the first controlled trial in the field of preoperative nutrition in liver transplantation. Finally, some papers provide further arguments in the dilemma of which route of nutrition (enteral or parenteral) is better in cirrhosis.

Nutritional support in alcoholic cirrhotic patients improves host defenses

BACKGROUND

Malnutrition is usual in patients with alcoholic liver disease and is associated with a poor outcome. Nutritional support decreases nutrition-associated complications.

AIM

To demonstrate that nutritional support in ambulatory alcoholic cirrhotic patients improves host defenses.

METHODS

Thirty-one male outpatients with alcoholic cirrhosis CHILD-PUGH B or C were included. Twenty-five subjects completed six months consuming daily a nutritional supplement (Ensure, 1000 Kcal and 35 g protein), in addition to their regular diet. At entrance and every three months, a clinical assessment, nutritional evaluation and indirect calorimetry were performed. Liver function tests and LPS-induced monocyte production of cytokines, salivary secretory IgA, lactulose/mannitol ratio and breath hydrogen tests were also measured in these intervals. Delayed cutaneous hypersensitivity and IgG and IgM antibody response to endotoxin were assessed at entrance and at the end of the study.

RESULTS

Patients drank 85% of the provided supplement as an average. REE, total body fat and serum albumin increased, basal breath hydrogen decreased and cellular immunity improved significantly during the follow up period (p< or =0.03). All the other parameters remained unchanged throughout the study. Six patients (16.2%) died during the study, five due to upper gastrointestinal bleeding.

CONCLUSION

Nutritional support in alcoholic cirrhotic patients improves nutritional status and cell mediated immunity.

Nutritional issues in cirrhosis and liver transplantation

In the past year, some relevant papers on the mechanisms of malnutrition in cirrhosis have been published. Studies investigating the metabolic destiny of leucine after protein breakdown, which have contributed to a better understanding of the pathogenesis of muscle wasting and fat depletion in these patients, deserve particular mention. Also, the demonstration that chronically reducing hyperinsulinaemia in cirrhosis is able to improve insulin sensitivity opens novel pathogenic and therapeutic perspectives for such a metabolic derangement in these patients. Other papers dealt with unsaturated lipids, lipoperoxidation and antioxidants in chronic liver disease. However, randomized trials on parenteral or enteral nutrition in cirrhosis and liver transplantation are missing.

Experience of parenteral nutrition for nutritional rescue in children with severe liver disease following failure of enteral nutrition

Nutritional support is often necessary in chronic liver disease in childhood, and when enteral nutrition is insufficient, parenteral nutrition (PN) can be envisaged as a last resort. Pediatric experience is still limited in this indication. Seven children with severe liver disease received PN for a mean duration of 105 d, with additional enteral nutrition. Clinical tolerance was assessed and anthropometric and biological data were compared at the beginning and at the end of the study by the paired non-parametric test of Wilcoxon. Weight change, expressed as weight-for-age or weight-for-height Z-scores, increased. Conjugated bilirubin increased significantly. This retrospective study suggests that PN is a well-tolerated method for maintaining nutritional status in pediatric chronic liver disease when enteral nutrition has failed.

Abnormalities in branched-chain amino acid metabolism in cirrhosis: influence of hormonal and nutritional factors and directions for future research

Plasma branched-chain amino acid (BCAA) levels are decreased in patients with liver cirrhosis, owing to an increase in BCAA tissue uptake and/or catabolism and a decrease in BCAA production from proteins. Non-specific factors such as malnutrition worsen this picture. Studies of BCAA fluxes and protein turnover in cirrhotic patients have given conflicting results due to patient heterogeneity, differences in method and bias in the expression of results. In well compensated cirrhosis, muscle wasting is moderate and probably due more to decreased protein synthesis than to increased protein catabolism. Hyperinsulinemia has been suggested as the main cause of decreased BCAA levels, by increasing BCAA uptake in muscle and additionally in adipose tissue. However, as depletion of fat stores is frequent in cirrhosis, this effect is certainly quantitatively weak. Also, there is no correlation between state of hyperinsulinemia and decrease in BCAA levels. An effect of cytokines (IL1 and TNF) on muscle BCAA catabolism is a possibility. Until recently, the contribution of the liver to abnormal BCAA metabolism has been underestimated. In cirrhotic liver an increase in liver transamination of branched-chain keto acids (BCKAs) has been suggested and may result from inhibition of liver BCKA dehydrogenase. A modification of protein turnover in cirrhotic liver must be also considered. Lastly, the contribution of non-hepatocyte liver cells, which are activated in cirrhosis, remains to be assessed.

Nutrition in chronic liver disease and liver transplantation

Significant contributions to the field of nutrition and liver disease have been published in the last year. The most relevant includes work on the pathogenic role of energy metabolism disturbances in the development of malnutrition in cirrhosis, as well as data on the relationship between preoperative nutritional deficiencies and the outcome of liver transplantation. However, despite these contributions, large-scale multicentric trials on the therapeutic value of nutritional support and metabolic care in cirrhosis and liver transplantation are still lacking.

Dietary nucleotides have cytoprotective properties in rat liver damaged by thioacetamide

Liver cirrhosis has been induced with thioacetamide administered via different routes in rats and other species. The oral intake of thioacetamide causes nodular liver cirrhosis in rats characterized by extensive fibrosis occupying most of the hepatic parenchyma. To characterize the cytological features of cirrhosis induced by thioacetamide, and the degree of recovery obtained with dietary nucleotides, we made a morphometric study of the hepatocytes in rats administered 300 mg/l of thioacetamide for 4 months, and in rats receiving the same hepatotoxic treatment but allowed a 2-weeks recovery period on a nucleotide-free diet or a 250 mg/100 g nucleotide-supplemented diet. Thioacetamide caused to cell damage and affected the ultrastructure of hepatocytes leading to a decrease in cytoplasmic area together with increased nuclear and nucleolar size. Dietary supplementation with nucleotides favoured recovery, restoring the cytoplasmic (TN=491.7+/-9.6 vs TAA=305.1+/-3.7), nuclear (73.6+/-2.8 vs 97.4+/-2.9), and nucleolar area of damaged hepatocytes (5.6+/-0.3 vs 14.0+/-0.9). The injury from thioacetamide intake increased liver collagen, but dietary nucleotides prevented hepatic deposition of this protein. This study supports the hypothesis that dietary supplementation with nucleotides is decisive in ensuring hepatocyte recovery after thioacetamide-induced liver damage, and that dietary nucleotides have antifibrotic properties.