Effects of supplementation with unsaturated fatty acids on plasma and membrane lipid composition and platelet function in patients with cirrhosis and defective aggregation

Nutritional support for liver disease

BACKGROUND

Weight loss and muscle wasting are commonly found in patients with end-stage liver disease. Since there is an association between malnutrition and poor clinical outcome, such patients (or those at risk of becoming malnourished) are often given parenteral nutrition, enteral nutrition, or oral nutritional supplements. These interventions have costs and adverse effects, so it is important to prove that their use results in improved morbidity or mortality, or both.

OBJECTIVES

To assess the beneficial and harmful effects of parenteral nutrition, enteral nutrition, and oral nutritional supplements on the mortality and morbidity of patients with underlying liver disease.

SEARCH METHODS

The following computerised databases were searched: the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, and Science Citation Index Expanded (January 2012). In addition, reference lists of identified trials and review articles and Clinicaltrials.gov were searched. Trials identified in a previous systematic handsearch of Index Medicus were also considered. Handsearches of a number of medical journals, including abstracts from annual meetings, were done. Experts in the field and manufacturers of nutrient formulations were contacted for potential references.

SELECTION CRITERIA

Randomised clinical trials (parallel or cross-over design) comparing groups of patients with any underlying liver disease who received, or did not receive, enteral or parenteral nutrition or oral nutritional supplements were identified without restriction on date, language, or publication status. Six categories of trials were separately considered: medical or surgical patients receiving parenteral nutrition, enteral nutrition, or supplements.

DATA COLLECTION AND ANALYSIS

The following data were sought in each report: date of publication; geographical location; inclusion and exclusion criteria; the type of nutritional support and constitution of the nutrient formulation; duration of treatment; any nutrition provided to the controls; other interventions provided to the patients; number, sex, age of the study participants; hospital or outpatient status; underlying liver disease; risks of bias (sequence generation, allocation concealment, blinding, incomplete outcome reporting, intention-to-treat analysis, selective outcome reporting, others (vested interests, baseline imbalance, early stopping)); mortality; hepatic morbidity (development or resolution of ascites or hepatic encephalopathy, occurrence of gastrointestinal bleeding); quality of life scores; adverse events; infections; lengths of stay in the hospital or intensive care unit; costs; serum bilirubin; postoperative complications (surgical trials only); and nutritional outcomes (nitrogen balance, anthropometric measurements, body weight). The primary outcomes of this review were mortality, hepatic morbidity, quality of life, and adverse events. Data were extracted in duplicate; differences were resolved by consensus.Data for each outcome were combined in a meta-analysis (RevMan 5.1). Estimates were reported using risk ratios or mean differences, along with the 95% confidence intervals (CI). Both fixed-effect and random-effects models were employed; fixed-effect models were reported unless one model, but not the other, found a significant difference (in which case both were reported). Heterogeneity was assessed by the Chi(2) test and I(2) statistic. Subgroup analyses were planned to assess specific liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma), acute or chronic liver diseases, and trials employing standard or branched-chain amino acid formulations (for the hepatic encephalopathy outcomes). Sensitivity analyses were planned to compare trials at low and high risk of bias and trials reported as full papers. The following exploratory analyses were undertaken: 1) medical and surgical trials were combined for each nutritional intervention; 2) intention-to-treat analyses in which missing dichotomous data were imputed as best- and worst-case scenarios; 3) all trials were combined to assess mortality; 4) effects were estimated by absolute risk reductions.

MAIN RESULTS

Thirty-seven trials were identified; only one was at low risk of bias. Most of the analyses failed to find any significant differences. The significant findings that were found were the following: 1) icteric medical patients receiving parenteral nutrition had a reduced serum bilirubin (mean difference (MD) -2.86 mg%, 95% CI -3.82 mg% to -1.89 mg%, 3 trials) and better nitrogen balance (MD 3.60 g/day, 95% CI 0.86 g/day to 6.34 g/day, 1 trial); 2) surgical patients receiving parenteral nutrition had a reduced incidence of postoperative ascites only in the fixed-effect model (RR 0.65, 95% CI 0.48 to 0.87, 2 trials, I(2) = 70%) and one trial demonstrated a reduction in postoperative complications, especially infections (pneumonia in particular); 3) enteral nutrition may have improved nitrogen balance in medical patients (although a combination of the three trials was not possible); 4) one surgical trial of enteral nutrition found a reduction in postoperative complications; and 5) oral nutritional supplements had several effects in medical patients (reduced occurrence of ascites (RR 0.57, 95% CI 0.37 to 0.88, 3 trials), possibly (significant differences only seen in the fixed-effect model) reduced rates of infection (RR 0.49, 95% CI 0.24 to 0.99, 3 trials, I(2) = 14%), and improved resolution of hepatic encephalopathy (RR 3.75, 95% CI 1.15 to 12.18, 2 trials, I(2) = 79%). While there was no overall effect of the supplements on mortality in medical patients, the one low risk of bias trial found an increased risk of death in the recipients of the supplements. Three trials of supplements in surgical patients failed to show any significant differences. No new information was derived from the various subgroup or sensitivity analyses. The exploratory analyses were also unrevealing except for a logical conundrum. There was no difference in mortality when all of the trials were combined, but the trials of parenteral nutrition found that those recipients had better survival (RR 0.53, 95% CI 0.29 to 0.98, 10 trials). Either the former observation represents a type II error or the latter one a type I error.

AUTHORS' CONCLUSIONS

The data do not compellingly justify the routine use of parenteral nutrition, enteral nutrition, or oral nutritional supplements in patients with liver disease. The fact that all but one of these trials were at high risks of bias even casts doubt on the few benefits that were demonstrated. Data from well-designed and executed randomised trials that include an untreated control group are needed before any such recommendation can be made. Future trials have to be powered adequately to see small, but clinically important, differences.

Nutritional support for liver disease

BACKGROUND

Weight loss and muscle wasting are commonly found in patients with end-stage liver disease. Since there is an association between malnutrition and poor clinical outcome, such patients (or those at risk of becoming malnourished) are often given parenteral nutrition, enteral nutrition, or oral nutritional supplements. These interventions have costs and adverse effects, so it is important to prove that their use results in improved morbidity or mortality, or both.

OBJECTIVES

To assess the beneficial and harmful effects of parenteral nutrition, enteral nutrition, and oral nutritional supplements on the mortality and morbidity of patients with underlying liver disease.

SEARCH METHODS

The following computerised databases were searched: the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, and Science Citation Index Expanded (January 2012). In addition, reference lists of identified trials and review articles and Clinicaltrials.gov were searched. Trials identified in a previous systematic handsearch of Index Medicus were also considered. Handsearches of a number of medical journals, including abstracts from annual meetings, were done. Experts in the field and manufacturers of nutrient formulations were contacted for potential references.

SELECTION CRITERIA

Randomised clinical trials (parallel or cross-over design) comparing groups of patients with any underlying liver disease who received, or did not receive, enteral or parenteral nutrition or oral nutritional supplements were identified without restriction on date, language, or publication status. Six categories of trials were separately considered: medical or surgical patients receiving parenteral nutrition, enteral nutrition, or supplements.

DATA COLLECTION AND ANALYSIS

The following data were sought in each report: date of publication; geographical location; inclusion and exclusion criteria; the type of nutritional support and constitution of the nutrient formulation; duration of treatment; any nutrition provided to the controls; other interventions provided to the patients; number, sex, age of the study participants; hospital or outpatient status; underlying liver disease; risks of bias (sequence generation, allocation concealment, blinding, incomplete outcome reporting, intention-to-treat analysis, selective outcome reporting, others (vested interests, baseline imbalance, early stopping)); mortality; hepatic morbidity (development or resolution of ascites or hepatic encephalopathy, occurrence of gastrointestinal bleeding); quality of life scores; adverse events; infections; lengths of stay in the hospital or intensive care unit; costs; serum bilirubin; postoperative complications (surgical trials only); and nutritional outcomes (nitrogen balance, anthropometric measurements, body weight). The primary outcomes of this review were mortality, hepatic morbidity, quality of life, and adverse events. Data were extracted in duplicate; differences were resolved by consensus.Data for each outcome were combined in a meta-analysis (RevMan 5.1). Estimates were reported using risk ratios or mean differences, along with the 95% confidence intervals (CI). Both fixed-effect and random-effects models were employed; fixed-effect models were reported unless one model, but not the other, found a significant difference (in which case both were reported). Heterogeneity was assessed by the Chi(2) test and I(2) statistic. Subgroup analyses were planned to assess specific liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma), acute or chronic liver diseases, and trials employing standard or branched-chain amino acid formulations (for the hepatic encephalopathy outcomes). Sensitivity analyses were planned to compare trials at low and high risk of bias and trials reported as full papers. The following exploratory analyses were undertaken: 1) medical and surgical trials were combined for each nutritional intervention; 2) intention-to-treat analyses in which missing dichotomous data were imputed as best- and worst-case scenarios; 3) all trials were combined to assess mortality; 4) effects were estimated by absolute risk reductions.

MAIN RESULTS

Thirty-seven trials were identified; only one was at low risk of bias. Most of the analyses failed to find any significant differences. The significant findings that were found were the following: 1) icteric medical patients receiving parenteral nutrition had a reduced serum bilirubin (mean difference (MD) -2.86 mg%, 95% CI -3.82 mg% to -1.89 mg%, 3 trials) and better nitrogen balance (MD 3.60 g/day, 95% CI 0.86 g/day to 6.34 g/day, 1 trial); 2) surgical patients receiving parenteral nutrition had a reduced incidence of postoperative ascites only in the fixed-effect model (RR 0.65, 95% CI 0.48 to 0.87, 2 trials, I(2) = 70%) and one trial demonstrated a reduction in postoperative complications, especially infections (pneumonia in particular); 3) enteral nutrition may have improved nitrogen balance in medical patients (although a combination of the three trials was not possible); 4) one surgical trial of enteral nutrition found a reduction in postoperative complications; and 5) oral nutritional supplements had several effects in medical patients (reduced occurrence of ascites (RR 0.57, 95% CI 0.37 to 0.88, 3 trials), possibly (significant differences only seen in the fixed-effect model) reduced rates of infection (RR 0.49, 95% CI 0.24 to 0.99, 3 trials, I(2) = 14%), and improved resolution of hepatic encephalopathy (RR 3.75, 95% CI 1.15 to 12.18, 2 trials, I(2) = 79%). While there was no overall effect of the supplements on mortality in medical patients, the one low risk of bias trial found an increased risk of death in the recipients of the supplements. Three trials of supplements in surgical patients failed to show any significant differences. No new information was derived from the various subgroup or sensitivity analyses. The exploratory analyses were also unrevealing except for a logical conundrum. There was no difference in mortality when all of the trials were combined, but the trials of parenteral nutrition found that those recipients had better survival (RR 0.53, 95% CI 0.29 to 0.98, 10 trials). Either the former observation represents a type II error or the latter one a type I error.

AUTHORS' CONCLUSIONS

The data do not compellingly justify the routine use of parenteral nutrition, enteral nutrition, or oral nutritional supplements in patients with liver disease. The fact that all but one of these trials were at high risks of bias even casts doubt on the few benefits that were demonstrated. Data from well-designed and executed randomised trials that include an untreated control group are needed before any such recommendation can be made. Future trials have to be powered adequately to see small, but clinically important, differences.

Recombinant activated factor VII in liver patients: a retrospective cohort study from Australia and New Zealand

Recombinant factor VIIa (rFVIIa) is used in the treatment of life-threatening haemorrhage that is refractory to conventional treatment. The evidence supporting this practice in patients with liver disease is very limited. It has been used as a salvage therapy in end-stage liver disease (ESLD), in orthotopic liver transplant (OLT), other surgery, and upper gastrointestinal bleeding (UGIB) subpopulations. It has also been used prior to procedures in patients with ESLD. Data were collected by the Australia and New Zealand Haemostasis Registry (ANZHR) to perform a retrospective cohort study on the different subgroups of liver patients. This included 115 cases of use of rFVIIa in liver patients from 20 hospitals. A retrospective cohort study on the different subgroups of liver patients was performed. Main outcome measures were reduction or cessation of bleeding and 28-day mortality. Variables previously shown to predict response to bleeding after administration of rFVIIa were examined to determine whether correlations exist. Salvage therapy with rFVIIa was associated with reduction or cessation in bleeding in 24 of 36 OLT patients, 24 of 36 UGIB patients and 15 of 26 of other surgery patients. Clinical response to rFVIIa in OLT patients and other surgery patients was associated with a significantly lower mortality compared to nonresponders (P = 0.003 and 0.022, respectively). There was no relationship between mortality and bleeding response in patients with UGIB. Variables including acidosis, hypothermia, hypofibrinogenaemia, thrombocytopenia and Model of End-Stage Liver Disease (MELD) score were not associated with clinical response to rFVIIa. Five cases of use prior to procedures are described. Recombinant FVIIa is used as rescue therapy in surgical patients with ESLD and refractory haemorrhage in Australia and New Zealand. Traditional haemostasis variables were not associated with clinical response to rFVIIa in this cohort. Response to rFVIIa is associated with decreased mortality in ESLD patients undergoing OLT and other surgery, but not in UGIB.

Influence of formulas with borage oil or borage oil plus fish oil on the arachidonic acid status in premature infants

Several studies have reported that feeding gamma-linolenic acid (GLA) has resulted in no increase in arachidonic acid (AA) in newborns. This result was ascribed to the eicosapentaenoic acid (EPA)-rich fish oil used in these formulas. Docosahexaenoic acid (DHA) sources with only minor amounts of EPA are now available, thus the addition of GLA to infant formulas might be considered an alternative to AA supplementation. Sixty-six premature infants were randomized to feeding one of four formulas [ST: no GLA, no long-chain polyunsaturated fatty acids; BO: 0.6% GLA (borage oil); BO + FOLOW: 0.6% GLA, 0.3% DHA, 0.06% EPA; BO + FOHIGH: 0.6% GLA, 0.3% DHA, 0.2% EPA] or human milk (HM, nonrandomized) for 4 wk. Anthropometric measures and blood samples were obtained at study entry and after 14 and 28 d. There were no significant differences between groups in anthropometric measures, tocopherol, and retinol status at any of the studied time points. The AA content of plasma phospholipids was similar between groups at study start and decreased significantly until day 28 in all formulafed groups, but not in the breast-fed infants [ST: 6.6 +/- 0.2%, BO: 6.9 +/- 0.3%, BO + FOLOW: 6.9 +/- 0.4%, BO + FOHIGH: 6.7 +/- 0.2%, HM: 8.6 +/- 0.5%, where values are reported as mean +/- standard error; all formulas significantly different (P< 0.05) from HM]. There was no significant influence of GLA or fish oil addition to the diet. GLA had only a very limited effect on AA status which was too small to obtain satisfactory concentrations (concentrations similar to breast-fed babies) under the circumstances tested. The effect of GLA on AA is independent of the EPA and DHA content in the diet within the dose ranges studied.

Nutritional and metabolic issues in cirrhosis and liver transplantation

In the last year some relevant papers on nutrition and metabolism in chronic liver disease and transplantation have been published. Studies investigating the reliability of predicting energy expenditure in cirrhosis, and some relevant contributions to the understanding of metabolic consequences of liver transplantation, deserve particular mention. These include the first direct evidence that liver transplantation corrects the insulin resistance present in cirrhosis, as well as studies on the role of genetic polymorphism of the vitamin D receptor gene in bone loss after transplantation. Other papers have dealt with body composition, polyunsaturated fatty acid and antioxidant status in cirrhosis. However, relevant contributions in the field of nutritional support in cirrhosis are surprisingly lacking.

1H-NMR lipid profiles of human blood platelets; links with coronary artery disease

Blood platelets are closely involved in the early development of atherosclerosis and in the events that lead to thrombosis, both of which are dominating factors in coronary artery disease (CAD). The aim of the present study was to evaluate the platelet lipid profiles of patients suffering from CAD and explore the possibility of a link between platelet lipids and CAD, using high-resolution high-field proton nuclear magnetic resonance spectroscopy as the analytical tool. The total platelet lipid profiles of healthy volunteers were compared with those of patients presenting with chest pain requiring coronary angiography. Two lipid groups changed significantly: cholesterol increased by 16.5% and total diacylglycerophospholipids decreased by 15.7%. There was also a significant decrease of the ethanolamine-containing phospholipids, by 4.7%; the extent of unsaturation of the fatty acid chains, by 0.2, and increase of the linoleate content of the fatty acid chains, by 1.9%. Our results suggest that platelet lipid abnormalities occur in patients with CAD and these changes may predate the development of overt atherosclerosis.

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.