Lactitol or lactulose in the treatment of chronic hepatic encephalopathy: results of a meta-analysis

Sarcopenia in cirrhosis: Prospects for therapy targeted to gut microbiota

Decreased muscle mass and function, also known as sarcopenia, is common in patients with cirrhosis and is associated with a poor prognosis. Although the pathogenesis of this disorder has not been fully elucidated, a disordered gut-muscle axis probably plays an important role. Decreased barrier function of the gut and liver, gut dysbiosis, and small intestinal bacterial overgrowth (SIBO) can lead to increased blood levels of ammonia, lipopolysaccharides, pro-inflammatory mediators, and myostatin. These factors have complex negative effects on muscle mass and function. Drug interventions that target the gut microbiota (long-term use of rifaximin, lactulose, lactitol, or probiotics) positively affect most links of the compromised gut-muscle axis in patients with cirrhosis by decreasing the levels of hyperammonemia, bacterial translocation, and systemic inflammation and correcting gut dysbiosis and SIBO. However, although these drugs are promising, they have not yet been investigated in randomized controlled trials specifically for the treatment and prevention of sarcopenia in patients with cirrhosis. No data exist on the effects of fecal transplantation on most links of gut-muscle axis in cirrhosis; however, the results of animal experimental studies are promising.

Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications

Prebiotics are a group of nutrients that are degraded by gut microbiota. Their relationship with human overall health has been an area of increasing interest in recent years. They can feed the intestinal microbiota, and their degradation products are short-chain fatty acids that are released into blood circulation, consequently, affecting not only the gastrointestinal tracts but also other distant organs. Fructo-oligosaccharides and galacto-oligosaccharides are the two important groups of prebiotics with beneficial effects on human health. Since low quantities of fructo-oligosaccharides and galacto-oligosaccharides naturally exist in foods, scientists are attempting to produce prebiotics on an industrial scale. Considering the health benefits of prebiotics and their safety, as well as their production and storage advantages compared to probiotics, they seem to be fascinating candidates for promoting human health condition as a replacement or in association with probiotics. This review discusses different aspects of prebiotics, including their crucial role in human well-being.

Distant Site Effects of Ingested Prebiotics

The gut microbiome is being more widely recognized for its association with positive health outcomes, including those distant to the gastrointestinal system. This has given the ability to maintain and restore microbial homeostasis a new significance. Prebiotic compounds are appealing for this purpose as they are generally food-grade substances only degraded by microbes, such as bifidobacteria and lactobacilli, from which beneficial short-chain fatty acids are produced. Saccharides such as inulin and other fructo-oligosaccharides, galactooligosaccharides, and polydextrose have been widely used to improve gastrointestinal outcomes, but they appear to also influence distant sites. This review examined the effects of prebiotics on bone strength, neural and cognitive processes, immune functioning, skin, and serum lipid profile. The mode of action is in part affected by intestinal permeability and by fermentation products reaching target cells. As the types of prebiotics available diversify, so too will our understanding of the range of microbes able to degrade them, and the extent to which body sites can be impacted by their consumption.

Non-absorbable disaccharides versus placebo/no intervention and lactulose versus lactitol for the prevention and treatment of hepatic encephalopathy in people with cirrhosis

BACKGROUND

Non-absorbable disaccharides (lactulose and lactitol) are recommended as first-line treatment for hepatic encephalopathy. The previous (second) version of this review included 10 randomised clinical trials (RCTs) evaluating non-absorbable disaccharides versus placebo/no intervention and eight RCTs evaluating lactulose versus lactitol for people with cirrhosis and hepatic encephalopathy. The review found no evidence to either support or refute the use of the non-absorbable disaccharides and no differences between lactulose versus lactitol.

OBJECTIVES

To assess the beneficial and harmful effects of i) non-absorbable disaccharides versus placebo/no intervention and ii) lactulose versus lactitol in people with cirrhosis and hepatic encephalopathy.

SEARCH METHODS

We carried out electronic searches of the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 10), MEDLINE, EMBASE, and Science Citation Index Expanded to 19 October 2015; manual searches of meetings and conference proceedings; checks of bibliographies; and correspondence with investigators and pharmaceutical companies.

SELECTION CRITERIA

We included RCTs, irrespective of publication status, language, or blinding.

DATA COLLECTION AND ANALYSIS

Two review authors, working independently, retrieved data from published reports and correspondence with investigators. The primary outcomes were mortality, hepatic encephalopathy, and serious adverse events. We presented the results of meta-analyses as risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI). We assessed the quality of the evidence using 'Grading of Recommendations Assessment Development and Evaluation' (GRADE) and bias control using the Cochrane Hepato-Biliary Group domains. Our analyses included regression analyses of publication bias and other small study effects, Trial Sequential Analyses to detect type 1 and type 2 errors, and subgroup and sensitivity analyses.

MAIN RESULTS

We included 38 RCTs with a total of 1828 participants. Eight RCTs had a low risk of bias in the assessment of mortality. All trials had a high risk of bias in the assessment of the remaining outcomes. Random-effects meta-analysis showed a beneficial effect of non-absorbable disaccharides versus placebo/no intervention on mortality when including all RCTs with extractable data (RR 0.59, 95% CI 0.40 to 0.87; 1487 participants; 24 RCTs; I(2) = 0%; moderate quality evidence) and in the eight RCTs with a low risk of bias (RR 0.63, 95% CI 0.41 to 0.97; 705 participants). The Trial Sequential Analysis with the relative risk reduction (RRR) reduced to 30% confirmed the findings when including all RCTs, but not when including only RCTs with a low risk of bias or when we reduced the RRR to 22%. Compared with placebo/no intervention, the non-absorbable disaccharides were associated with beneficial effects on hepatic encephalopathy (RR 0.58, 95% CI 0.50 to 0.69; 1415 participants; 22 RCTs; I(2) = 32%; moderate quality evidence). Additional analyses showed that non-absorbable disaccharides can help to reduce serious adverse events associated with the underlying liver disease including liver failure, hepatorenal syndrome, and variceal bleeding (RR 0.47, 95% CI 0.36 to 0.60; 1487 participants; 24 RCTs; I(2) = 0%; moderate quality evidence). We confirmed the results in Trial Sequential Analysis. Tests for subgroup differences showed no statistical differences between RCTs evaluating prevention, overt, or minimal hepatic encephalopathy. The evaluation of secondary outcomes showed a potential beneficial effect of the non-absorbable disaccharides on quality of life, but we were not able to include the data in an overall meta-analysis (very low quality evidence). Non-absorbable disaccharides were associated with non-serious (mainly gastrointestinal) adverse events (very low quality evidence). None of the RCTs comparing lactulose versus lactitol evaluated quality of life. The review found no differences between lactulose and lactitol for the remaining outcomes (very low quality evidence).

AUTHORS' CONCLUSIONS

This review includes a large number of RCTs evaluating the prevention or treatment of hepatic encephalopathy. The analyses found evidence that non-absorbable disaccharides may be associated with a beneficial effect on clinically relevant outcomes compared with placebo/no intervention.

Non-absorbable disaccharides versus placebo/no intervention and lactulose versus lactitol for the prevention and treatment of hepatic encephalopathy in people with cirrhosis

BACKGROUND

Non-absorbable disaccharides (lactulose and lactitol) are recommended as first-line treatment for hepatic encephalopathy. The previous (second) version of this review included 10 randomised clinical trials (RCTs) evaluating non-absorbable disaccharides versus placebo/no intervention and eight RCTs evaluating lactulose versus lactitol for people with cirrhosis and hepatic encephalopathy. The review found no evidence to either support or refute the use of the non-absorbable disaccharides and no differences between lactulose versus lactitol.

OBJECTIVES

To assess the beneficial and harmful effects of i) non-absorbable disaccharides versus placebo/no intervention and ii) lactulose versus lactitol in people with cirrhosis and hepatic encephalopathy.

SEARCH METHODS

We carried out electronic searches of the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 10), MEDLINE, EMBASE, and Science Citation Index Expanded to 19 October 2015; manual searches of meetings and conference proceedings; checks of bibliographies; and correspondence with investigators and pharmaceutical companies.

SELECTION CRITERIA

We included RCTs, irrespective of publication status, language, or blinding.

DATA COLLECTION AND ANALYSIS

Two review authors, working independently, retrieved data from published reports and correspondence with investigators. The primary outcomes were mortality, hepatic encephalopathy, and serious adverse events. We presented the results of meta-analyses as risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI). We assessed the quality of the evidence using 'Grading of Recommendations Assessment Development and Evaluation' (GRADE) and bias control using the Cochrane Hepato-Biliary Group domains. Our analyses included regression analyses of publication bias and other small study effects, Trial Sequential Analyses to detect type 1 and type 2 errors, and subgroup and sensitivity analyses.

MAIN RESULTS

We included 38 RCTs with a total of 1828 participants. Eight RCTs had a low risk of bias in the assessment of mortality. All trials had a high risk of bias in the assessment of the remaining outcomes. Random-effects meta-analysis showed a beneficial effect of non-absorbable disaccharides versus placebo/no intervention on mortality when including all RCTs with extractable data (RR 0.59, 95% CI 0.40 to 0.87; 1487 participants; 24 RCTs; I(2) = 0%; moderate quality evidence) and in the eight RCTs with a low risk of bias (RR 0.63, 95% CI 0.41 to 0.97; 705 participants). The Trial Sequential Analysis with the relative risk reduction (RRR) reduced to 30% confirmed the findings when including all RCTs, but not when including only RCTs with a low risk of bias or when we reduced the RRR to 22%. Compared with placebo/no intervention, the non-absorbable disaccharides were associated with beneficial effects on hepatic encephalopathy (RR 0.58, 95% CI 0.50 to 0.69; 1415 participants; 22 RCTs; I(2) = 32%; moderate quality evidence). Additional analyses showed that non-absorbable disaccharides can help to reduce serious adverse events associated with the underlying liver disease including liver failure, hepatorenal syndrome, and variceal bleeding (RR 0.47, 95% CI 0.36 to 0.60; 1487 participants; 24 RCTs; I(2) = 0%; moderate quality evidence). We confirmed the results in Trial Sequential Analysis. Tests for subgroup differences showed no statistical differences between RCTs evaluating prevention, overt, or minimal hepatic encephalopathy. The evaluation of secondary outcomes showed a potential beneficial effect of the non-absorbable disaccharides on quality of life, but we were not able to include the data in an overall meta-analysis (very low quality evidence). Non-absorbable disaccharides were associated with non-serious (mainly gastrointestinal) adverse events (very low quality evidence). None of the RCTs comparing lactulose versus lactitol evaluated quality of life. The review found no differences between lactulose and lactitol for the remaining outcomes (very low quality evidence).

AUTHORS' CONCLUSIONS

This review includes a large number of RCTs evaluating the prevention or treatment of hepatic encephalopathy. The analyses found evidence that non-absorbable disaccharides may be associated with a beneficial effect on clinically relevant outcomes compared with placebo/no intervention.

Advances in cirrhosis: Optimizing the management of hepatic encephalopathy

Hepatic encephalopathy (HE) is a major complication of cirrhosis resulting in significant socioeconomic burden, morbidity, and mortality. HE can be further subdivided into covert HE (CHE) and overt HE (OHE). CHE is a subclinical, less severe manifestation of HE and requires psychometric testing for diagnosis. Due to the time consuming screening process and lack of standardized diagnostic criteria, CHE is frequently underdiagnosed despite its recognized role as a precursor to OHE. Screening for CHE with the availability of the Stroop test has provided a pragmatic method to promptly diagnose CHE. Management of acute OHE involves institution of lactulose, the preferred first-line therapy. In addition, prompt recognition and treatment of precipitating factors is critical as it may result in complete resolution of acute episodes of OHE. Treatment goals include improvement of daily functioning, evaluation for liver transplantation, and prevention of OHE recurrence. For secondary prophylaxis, intolerance to indefinite lactulose therapy may lead to non-adherence and has been identified as a precipitating factor for recurrent OHE. Rifaximin is an effective add-on therapy to lactulose for treatment and prevention of recurrent OHE. Recent studies have demonstrated comparable efficacy of probiotic therapy to lactulose use in both primary prophylaxis and secondary prophylaxis.

Recent advances in the treatment of hyperammonemia

Ammonia is a neurotoxic agent that is primarily generated in the intestine and detoxified in the liver. Toxic increases in systemic ammonia levels predominantly result from an inherited or acquired impairment in hepatic detoxification and lead to potentially life-threatening neuropsychiatric symptoms. Inborn deficiencies in ammonia detoxification mainly affect the urea cycle, an endogenous metabolic removal system in the liver. Hepatic encephalopathy, on the other hand, is a hyperammonemia-related complication secondary to acquired liver function impairment. A range of therapeutic options is available to target either ammonia generation and absorption or ammonia removal. Therapies for hepatic encephalopathy decrease intestinal ammonia production and uptake. Treatments for urea cycle disorders eliminate ammoniagenic amino acids through metabolic transformation, preventing ammonia generation. Therapeutic approaches removing ammonia activate the urea cycle or the second essential endogenous ammonia detoxification system, glutamine synthesis. Recent advances in treating hyperammonemia include using synergistic combination treatments, broadening the indication of orphan drugs, and developing novel approaches to regenerate functional liver tissue. This manuscript reviews the various pharmacological treatments of hyperammonemia and focuses on biopharmaceutical and drug delivery issues.

Management of overt hepatic encephalopathy

Hepatic encephalopathy (HE) is an important complication of cirrhosis with significant morbidity and mortality. Management of HE primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as non-absorbable disaccharides, antimicrobial agents like rifaximin and l-ornithine l-aspartate. The non-absorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and in primary and secondary prophylaxis of HE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Rifaximin is effective in treatment of HE and recent systemic reviews found it comparable to disaccharides and is effective in secondary prophylaxis of HE. Many agents like l-ornithine l-aspartate, probiotics, zinc, sodium benzoate have been tried either alone or in combination with lactulose for the treatment of HE. Combination therapy of disaccharides either with rifaximin, l-ornithine l-aspartate, probiotics for the treatment of HE needs further validation in large studies.

Disaccharides in the treatment of hepatic encephalopathy

Management of hepatic encephalopathy (HE) primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as nonabsorbable disaccharides and antimicrobial agents like rifaximin. The nonabsorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and minimal hepatic encephalopathy (MHE). Lactulose significantly improves cognitive function and health-related quality of life in patients with MHE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Lactulose has also shown to be effective in primary and secondary prophylaxis of HE. Disaccharides were found to be comparable to rifaximin in recent systemic reviews in the treatment of HE however conclusion was based on inclusion of some poor quality trials. Combination therapy of disaccharides either with rifaximin, L-ornithine L-aspartate,probiotics for the treatment of HE needs further validation in large studies.

Hepatic encephalopathy: a review of its pathophysiology and treatment

Hepatic encephalopathy (HE) is a broad spectrum of neuropsychiatric manifestations usually affecting individuals with end-stage liver disease. The presence of HE is a poor prognostic sign, with 1-year mortality rates of almost 60%. There is much debate about the underlying mechanisms that result in this syndrome; however, elevated plasma and central nervous system ammonia levels are considered key factors in its pathogenesis. Initial evaluation of the patient presenting with overt HE should include a careful search for predisposing factors, including underlying infection, gastrointestinal (GI) bleeding, electrolyte disturbances, hepatocellular carcinoma, dehydration, hypotension, and excessive use of benzodiazepines, psychoactive drugs, or alcohol. The mainstay of treatment for many years has been nonabsorbable disaccharides, particularly lactulose. Alternative treatments, which usually are second line in patients who do not respond to lactulose, include zinc, antibiotics (neomycin, metronidazole, and rifaximin), ornithine aspartate, sodium benzoate, probiotics, and surgical intervention. Accepted treatments for HE are associated with significant unpleasant side effects, including diarrhea, renal failure, neuropathy, and other GI disturbance. Newer therapies are still in development, and most are awaiting human trials in order to confirm their benefit. These include manganese chelators, L-carnitine, N-methyl-d-aspartate receptor antagonists, blood purification dialysis system, and an intravenous combination of sodium benzoate and phenylacetate.

[Hepatic encephalopathy and liver transplantation]

About 6500-7000 people/year die in Hungary due to liver cirrhosis which is often complicated with hepatic encephalopathy (HE). While conventional interpretation is that hepatic encephalopathy is a consequence of high blood ammonia level, recent data indicate that the degree of encephalopathy is related to systemic inflammatory response during decompensation. In this review the authors overview and analyze the latest treatment modalities of hepatic encephalopathy based on most recent findings. They found that frequently used evidence based treatment which apply metronidazole, neomycine or disaccharides was only partially effective in clinical studies. Use of rifaximine only is supported by grade I evidence, however it is quite a costly drug. The authors could not identify a generally accepted guideline for the treatment of HE with a systematic literature review, although it has significant effect on survival after liver transplantation. Therefore, the authors urge to develop a consensus guideline for the treatment of HE.

Profile of hepatic encephalopathy in children with cirrhosis and response to lactulose

BACKGROUND/AIM

Hepatic encephalopathy (HE) is associated with a poor prognosis. There is paucity of data on the treatment of HE with lactulose in children with cirrhosis.

PATIENTS AND METHODS

Retrospective analysis of consecutive cirrhotic patients (<18 years) with HE was done. HE was defined according to West-Haven criteria. Response was defined as complete if patients recovered completely from HE, partial response was defined as improvement of encephalopathy by one or more grades from admission but not complete recovery, and defined as non response if patient did not show any improvement or deteriorated further even after 10 days of lactulose therapy.

RESULTS

A total of 300 patients were admitted with cirrhosis and HE (278 adults and 22 children). Of 22 patients, 16 (73%) patients had complete response to lactulose and six (27%) patients did not [three (13.5%) patients worsened (non response) and three (13.5%) did not recover fully even after 10 days of treatment (partial response)]. Comparing baseline characteristics of patients who had complete response (n=16) versus partial (n=3) and non response (n=3), there was significant difference in mean arterial pressure (78.1±10.7 vs 62.6±5.0 mmHg, P=0.003), serum sodium (131.3±3.2 vs 126.5±5.2, P=0.01) and serum creatinine (0.78±0.3 vs 1.1±0.3 mg/dl, P=0.02). We did not find any difference in baseline characteristics of these patients regarding CTP score (9.6±1.2 vs 10.6±1.2), MELD score (17.6±2.9 vs 17.1±3.4), severity of HE (2.5±0.6 vs 2.6±0.5) and etiology of precipitating factors (P=0.78).

CONCLUSIONS

Lactulose therapy causes complete recovery from hepatic encephalopathy in 73% of pediatrics patients with cirrhosis.

Hepatic encephalopathy: from pathophysiology to therapeutic management

Hepatic encephalopathy is a complex and potentially reversible neuropsychiatric syndrome complicating acute or chronic liver disease. Clinical manifestations are multiple and varied, ranging from minimal neurological changes to coma. Ammonia is the main toxic substance involved in the pathogenesis of hepatic encephalopathy, although other mechanisms, such as modifications of the blood-brain barrier, disruptions in neurotransmission and abnormalities in GABAergic and benzodiazepine pathways may also play a role. The identification and treatment of precipitating factors is crucial in the management of patients with hepatic encephalopathy. Current treatments are based on reducing intestinal ammonia load by agents such as antibiotics or disaccharides, although their efficacy is yet to be clearly established.

Predictors of nonresponse to lactulose in patients with cirrhosis and hepatic encephalopathy

BACKGROUND AND AIMS

Lactulose is commonly used in the treatment of hepatic encephalopathy (HE). However, all patients do not respond to lactulose. We evaluated predictors of nonresponse to lactulose in patients with cirrhosis and HE.

PATIENTS AND METHODS

Consecutive cirrhotic patients with HE were enrolled. HE was diagnosed by West Haven criteria. Patients were treated with lactulose and correction of any associated precipitating factors. Nonresponse was defined if patient remained in HE even after 10 days of treatment or died while in HE.

RESULTS

Of 300 patients with cirrhosis and HE, 231 (77%) patients met the inclusion criteria. The majority (95%) of the patients had Grade 2 or 3 HE. Of 231 patients, 180 (78%) responded to lactulose. Fifty-one (22%) did not respond to lactulose, 34 (15%) died without any improvement in HE and HE did not improve in 17 (7%) patients after 10 days of therapy. On comparing baseline parameters between nonresponders versus responders there was significant difference between baseline age (42.0+/-11.9 vs. 46.6+/-12.7 year, P=0.02), total leukocyte count (median, 9300 vs. 7300 cells/mm3, P=0.001), serum sodium level (129.9+/-6.2 vs. 133.7+/-7.1 mmol/l, P=0.001), model for end stage liver disease (MELD) score (22.9+/-3.8 vs. 19.9+/-4.2, P=0.001), mean arterial pressure (MAP, 77.9+/-10.0 vs. 86.3+/-8.7 mmHg, P=0.001), serum AST (median, 114 vs. 76 IU/l, P=0.01), serum ALT (median, 84 vs. 48.5 IU/l, P=0.001), spontaneous bacterial peritonitis [18 (35%) vs. 37 (21%), P=0.02] and hepatocellular carcinoma [HCC, 17 (33%) vs. 14 (7%), P=0.001]. On multivariate analysis baseline total leukocyte count, MELD, MAP, and HCC were independent predictors of nonresponse to lactulose (P=0.001). Combination of low MAP, high MELD, and presence of HCC had diagnostic accuracy of 81% in predicting nonresponse to lactulose.

CONCLUSION

Of 78% patients with chronic liver disease with HE (majority with Grade 2 and 3) responded to lactulose. High baseline MELD, high total leukocyte count, low serum sodium, low MAP, and presence of hepatocellular carcinoma were predictors of nonresponse to lactulose.

Considerations on the impact of hepatic encephalopathy treatments in the pretransplant setting

Hepatic encephalopathy (HE) is a common complication of acute and chronic liver disease associated with exposure of brain tissue to excessive levels of ammonia produced by intestinal bacteria. Clinical manifestations range from subtle neurologic abnormalities to coma. Because development of HE can reduce survival probability, guidelines for evaluating patients for liver transplantation suggest that patients who develop HE should be considered for transplantation. Various patient factors before transplantation, including the presence of HE and reduced nutritional status, may increase the risk of poor outcomes after transplantation. Therefore, effective management of HE before transplantation, while minimizing the potential impact of negative predictive factors, may improve transplantation outcomes. The most common HE treatments are directed toward reducing systemic ammonia levels, thereby reducing brain exposure to this neurotoxin. The administration of nonabsorbable disaccharides is considered as a first-line therapy for HE, and the antibiotics neomycin and metronidazole are frequently administered, despite a lack of clinical data supporting their efficacy. These agents are associated with adverse events that may reduce nutritional status in patients awaiting transplantation and could contribute to poor posttransplantation outcomes. The nonsystemic antibiotic rifaximin has demonstrated efficacy for the treatment of HE and has a favorable safety profile. Given these data, nonsystemic antibiotics may also provide a safe and effective option for treating HE in the pretransplant setting. This article reviews treatments for HE and the potential impact these treatments may have on pretransplantation status of patients awaiting liver transplantation and on posttransplantation outcomes.

Current concepts in the assessment and treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is defined as a metabolically induced, potentially reversible, functional disturbance of the brain that may occur in acute or chronic liver disease. Standardized nomenclature has been proposed but a standardized approach to the treatment, particularly of persistent, episodic and recurrent encephalopathy associated with liver cirrhosis has not been proposed. This review focuses on the pathogenesis and treatment of HE in patients with cirrhosis. The pathogenesis and treatment of hepatic encephalopathy in fulminant hepatic failure is quite different and is reviewed elsewhere.

Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties

Abstract Polyols are hydrogenated carbohydrates used as sugar replacers. Interest now arises because of their multiple potential health benefits. They are non-cariogenic (sugar-free tooth-friendly), low-glycaemic (potentially helpful in diabetes and cardiovascular disease), low-energy and low-insulinaemic (potentially helpful in obesity), low-digestible (potentially helpful in the colon), osmotic (colon-hydrating, laxative and purifying) carbohydrates. Such potential health benefits are reviewed. A major focus here is the glycaemic index (GI) of polyols as regards the health implications of low-GI foods. The literature on glycaemia and insulinaemia after polyol ingestion was analysed and expressed in the GI and insulinaemic index (II) modes, which yielded the values: erythritol 0, 2; xylitol 13, 11; sorbitol 9, 11; mannitol 0, 0; maltitol 35, 27; isomalt 9, 6; lactitol 6, 4; polyglycitol 39, 23. These values are all much lower than sucrose 65, 43 or glucose 100, 100. GI values on replacing sucrose were independent of both intake (up to 50 g) and the state of carbohydrate metabolism (normal, type 1 with artificial pancreas and type 2 diabetes mellitus). The assignment of foods and polyols to GI bands is considered, these being: high (> 70), intermediate (> 55–70), low (> 40–55), and very low (< 40) including non-glycaemic; the last aims to target particularly low-GI-carbohydrate-based foods. Polyols ranged from low to very low GI. An examination was made of the dietary factors affecting the GI of polyols and foods. Polyol and other food GI values could be used to estimate the GI of food mixtures containing polyols without underestimation. Among foods and polyols a departure of II from GI was observed due to fat elevating II and reducing GI. Fat exerted an additional negative influence on GI, presumed due to reduced rates of gastric emptying. Among the foods examined, the interaction was prominent with snack foods; this potentially damaging insulinaemia could be reduced using polyols. Improved glycated haemoglobin as a marker of glycaemic control was found in a 12-week study of type 2 diabetes mellitus patients consuming polyol, adding to other studies showing improved glucose control on ingestion of low-GI carbohydrate. In general some improvement in long-term glycaemic control was discernible on reducing the glycaemic load via GI by as little as 15–20 g daily. Similar amounts of polyols are normally acceptable. Although polyols are not essential nutrients, they contribute to clinically recognised maintenance of a healthy colonic environment and function. A role for polyols and polyol foods to hydrate the colonic contents and aid laxation is now recognised by physicians. Polyols favour saccharolytic anaerobes and aciduric organisms in the colon, purifying the colon of endotoxic, putrefying and pathological organisms, which has clinical relevance. Polyols also contribute towards short-chain organic acid formation for a healthy colonic epithelium. Polyol tooth-friendliness and reduced energy values are affirmed and add to the potential benefits. In regard to gastrointestinal tolerance, food scientists and nutritionists, physicians, and dentists have in their independent professional capacities each now described sensible approaches to the use and consumption of polyols.

Non-absorbable disaccharides for hepatic encephalopathy: systematic review of randomised trials

OBJECTIVE

To assess the effects of non-absorbable disaccharides (lactulose and lactitol) in patients with hepatic encephalopathy.

DATA SOURCES

Cochrane Hepato-Biliary Group controlled trials register, Cochrane Library, Medline, and Embase until March 2003; reference lists of relevant articles; authors and pharmaceutical companies.

REVIEW METHODS

Randomised trials that compared non-absorbable disaccharides with placebo, no intervention, or antibiotics for hepatic encephalopathy were included. The primary outcome measures were no improvement of hepatic encephalopathy and all cause mortality.

RESULTS

22 trials were included. Compared with placebo or no intervention, non-absorbable disaccharides seemed to reduce the risk of no improvement in patients with hepatic encephalopathy (relative risk 0.62, 95% confidence interval 0.46 to 0.84, six trials). However, high quality trials found no significant effect (0.92, 0.42 to 2.04, two trials). Compared with placebo or no intervention, non-absorbable disaccharides had no significant effect on mortality (0.41, 0.02 to 8.68, four trials). Non-absorbable disaccharides were inferior to antibiotics in reducing the risk of no improvement (1.24, 1.02 to 1.50, 10 trials) and lowering blood ammonia concentration (weighted mean difference 2.35 micromol/l, 0.06 micromol/l to 13.45 micromol/l, 10 trials). There was no significant difference in mortality (0.90, 0.48 to 1.67, five trials).

CONCLUSIONS

There is insufficient evidence to support or refute the use of non-absorbable disaccharides for hepatic encephalopathy. Antibiotics were superior to non-absorbable disaccharides in improving hepatic encephalopathy, but it is unclear whether this difference is clinically important. Non-absorbable disaccharides should not serve as comparator in randomised trials on hepatic encephalopathy.

Nonabsorbable disaccharides for hepatic encephalopathy

BACKGROUND

Nonabsorbable disaccharides (lactulose or lactitol) are considered the treatment of choice for hepatic encephalopathy.

OBJECTIVES

To assess the beneficial and harmful effects of nonabsorbable disaccharides for patients with hepatic encephalopathy.

SEARCH STRATEGY

Trials were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register (March 2003), The Cochrane Central Register of Controlled Trials (Issue 1, 2003), MEDLINE (1966 to 2003/03), EMBASE (1980 to 2003/03), manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing lactulose or lactitol versus no intervention, placebo, or antibiotics and trials comparing lactulose versus lactitol for hepatic encephalopathy.

DATA COLLECTION AND ANALYSIS

The primary outcome measures included no improvement of hepatic encephalopathy and all-cause mortality. Binary outcomes are reported as relative risks (RR) based on a random effects model. Subgroup analyses were performed with regard to methodological quality and form of hepatic encephalopathy.

MAIN RESULTS

Thirty trials assessed nonabsorbable disaccharides versus placebo, no intervention, or antibiotics or assessed lactulose versus lactitol. We could not extract data from all trials. Compared with placebo or no intervention, nonabsorbable disaccharides had no statistically significant effect on mortality (RR 0.41, 95% CI 0.02 to 8.68, four trials), but appeared to reduce the risk of no improvement of hepatic encephalopathy (RR 0.62, 95% CI 0.46 to 0.84, six trials). However, this result may reflect bias due to low methodological quality of the majority of included trials. Trials of high methodological quality found no significant effect of nonabsorbable disaccharides on the risk of no improvement (RR 0.92, 95% CI 0.42 to 2.04, two trials). We found no statistically significant difference between lactulose and lactitol on mortality (two trials) or risk of no improvement (four trials). However, our meta-analyses were underpowered to establish whether these treatments have comparable effect. Nonabsorbable disaccharides appeared to be inferior to antibiotics on reducing the risk of no improvement (RR 1.24, 95% CI 1.02 to 1.50, 10 trials).

REVIEWERS' CONCLUSIONS

This systematic review questions the beneficial effects of nonabsorbable disaccharides and highlights that there is insufficient high-quality evidence to support this treatment. We found that antibiotics appeared to be superior to nonabsorbable disaccharides in improving hepatic encephalopathy, but it is unclear whether this difference in treatment effect is clinically important to patients. Nonabsorbable disaccharides should not serve as comparator in randomised trials on hepatic encephalopathy.

Effects of lactulose and lactitol on coliform bacteria and bacterial translocation in the caecum during 72-h starvation in rats

Lactulose and lactitol, non-absorbable disaccharides, prevent bacterial translocation (BT) arising from the gut. In contrast, lack of food into the gut leads to coliform bacterial overgrowth and even if it does not cause BT, can induce the risk from other stimuli for BT. In this study, we tested whether lactulose and lactitol affected populations of coliform bacteria in the caecum during starvation in Sprague-Dawley rats. Three groups of rats were starved for 72 h and given oral 2 ml undiluted lactulose (670 mg/ml), 2 ml undiluted lactitol (666 mg/ml) or 2 ml physiological saline, respectively, once a day. The caecum and mesenteric lymph nodes (MLNs) were removed for microbiological and histopathological analyses. The highest degree of coliform bacterial overgrowth, BT to MLNs and histopathological damage were observed in lactulose-treated rats, followed by the group treated with lactitol. As a result of this study, both drugs, especially lactulose augmented the proliferation and translocation tendency of coliform bacteria in the caecum during 72-h starvation in rats.

Management of hepatic encephalopathy

Hepatic encephalopathy (HE) is seen as a clinical manifestation of low grade chronic cerebral edema, which is accompanied by alterations in glioneural communication. Different factors such as ammonia, inflammatory cytokines, benzodiazepines and electrolyte imbalances may precipitate or aggravate glia edema, thereby explaining precipitation of HE episodes by a variety of unrelated factors. Recognition and rigorous treatment of these precipitating factors is the most important measure in HE therapy which may be augmented by dietary and medical approaches. Among these approaches, evidence for proven therapeutical efficacy in HE on the basis of placebo-controlled trials is existing only for transplantation, protein restriction, administration of vegetable proteins, ornithine-aspartate, oral branched-chain amino acid treatment as well as lactulose enemas. The efficacy of oral lactulose has not been demonstrated on the basis of placebo-controlled trials.

Hepatic Encephalopathy

1. Acute Encephalopathy in Cirrhosis A. GENERAL MEASURES. Tracheal intubation in patients with deep encephalopathy should be considered. A nasogastric tube is placed for patients in deep encephalopathy. Avoid sedatives whenever possible. Correction of the precipitating factor is the most important measure. B. SPECIFIC MEASURES i. Nutrition. In case of deep encephalopathy, oral intake is withheld for 24-48 h and i.v. glucose is provided until improvement. Enteral nutrition can be started if the patient appears unable to eat after this period. Protein intake begins at a dose of 0.5 g/kg/day, with progressive increase to 1-1.5 g/kg/day. ii. Lactulose is administered via enema or nasogastric tube in deep encephalopathy. The oral route is optimized by dosing every hour until stool evacuation appears. Lactulose can be replaced by oral neomycin. iii. Flumazenil may be used in selected cases of suspected benzodiazepine use. 2. Chronic Encephalopathy in Cirrhosis i. Avoidance and prevention of precipitating factors, including the institution of prophylactic measures. ii. Nutrition. Improve protein intake by feeding dairy products and vegetable-based diets. Oral branched-chain amino acids can be considered for individuals intolerant of all protein. iii. Lactulose. Dosing aims at two to three soft bowel movements per day. Antibiotics are reserved for patients who respond poorly to disaccharides or who do not exhibit diarrhea or acidification of the stool. Chronic antibiotic use (neomycin, metronidazole) requires careful renal, neurological, and/or otological monitoring. iv. Refer for liver transplantation in appropriate candidates. For problematic encephalopathy (nonresponsive to therapy), consider imaging of splanchnic vessels to identify large spontaneous portal-systemic shunts potentially amenable to radiological occlusion. In addition, consider the combination of lactulose and neomycin, addition of oral zinc, and invasive approaches, such as occlusion of TIPS or surgical shunts, if present. Minimal or Subclinical Encephalopathy Treatment can be instituted in selected cases. The most characteristic neuropsychological deficits in patients with cirrhosis are in motor and attentional skills (60). Although these may impact the ability to perform daily activities, many subjects can compensate for these defects. Recent studies suggest a small but significant impact of these abnormalities on patients' quality of life (61), including difficulties with sleep (62). In patients with significant deficits or complaints, a therapeutic program based on dietary manipulations and/or nonabsorbable disaccharides may be tried. Benzodiazepines should not be used for patients with sleep difficulties.

Hepatic encephalopathy in liver cirrhosis: pathogenesis, diagnosis and management

The pathogenesis of hepatic encephalopathy (HE) is unknown. Many theories have been proposed. Most established therapies are based on such theories but since no theory has have ever been proved, therapies have to be considered empiric. The spectrum of HE ranges from minimal cerebral functional deficits, which can only be found by sensitive psychometric tests, to coma with signs of decerebration. HE has arbitrarily been divided into stages. A number of precipitating factors are known and the first line of therapy should always be the elimination of these factors. The differential diagnosis includes all states of impaired consciousness and deficits in cerebral function in patients with chronic liver disease, and clinical and biochemical tests to differentiate are indicated. The therapeutic options for HE include: protein restriction only for a limited time in comatous patients; nonabsorbable antibiotics (aminoglycosides), which because of adverse effects are also limited to higher grades of HE: intestinal cleansing which is applicable in all degrees of HE; lactulose, branched chain aminoacids and ornithin aspartate which have been proven to be effective and can be applied long term in patients with lower grades of HE.

Effect of lactitol on blood ammonia response to oral glutamine challenge in cirrhotic patients: evidence for an effect of nonabsorbable disaccharides on small intestine ammonia generation

OBJECTIVE

Nonabsorbable disaccharides are widely used to decrease blood ammonia concentration. Their principal mode of action is the modification of pH and bacterial flora in the colon. The aim of the present study was to test the hypothesis that these drugs may also reduce small intestine ammonia generation.

METHODS

Eight male cirrhotics without overt hepatic encephalopathy received 20 g of glutamine in 100 ml of water. Venous samples for whole blood ammonia were taken before, 30 and 60 min after the load. Immediately after the last blood sample the patients were submitted to the following psychometric tests: number connection test, Posner's attention test, and Sternberg paradigm. After the first glutamine load, patients were started on lactitol (initial dose 20 g, three times a day). Once two bowel movements/day were obtained and maintained for at least 5 days, oral glutamine challenge and psychometric tests were repeated.

RESULTS

Ammonia increased significantly after the glutamine load (from 83 +/- 13 to 164 +/- 30 microg/dl at 30 min and 210 +/- 29 microg/dl at 60 min; mean +/- SE; p = 0.006 analysis of variance) but not after glutamine load after lactitol treatment (from 77 +/- 17 to 111 +/- 21 microg/dl and 142 +/- 24 microg/dl; p = not significant). The peak increment (127 +/- 24 vs 65 +/- 18 microg/dl; p = 0.008) of ammonia elevation was significantly smaller during lactitol administration. The patients' psychometric performance after the glutamine load did not differ significantly after lactitol treatment.

CONCLUSIONS

Lactitol reduces the elevation in blood ammonia that follows oral glutamine challenge. Because enterally administered glutamine is efficiently absorbed in the jejunum and, in part, metabolized to ammonia we suggest that lactitol affects small intestine ammonia generation probably by shortening the residence time of intestinal contents.

Effects of lactulose and lactitol on colonic microflora and enzymatic activity

The effects of lactulose and lactitol (2 x 10 g/d) were studied in 36 healthy volunteers in comparison to placebo. All parameters studied were affected by both treatments, lactulose in general leading to more pronounced changes compared to lactitol. Probiotic bacteria were increased, and putrefactive bacteria and potential pathogens were significantly reduced. These variations in colonic flora had the following consequences: (i) a reduced activity of pro-carcinogenic enzymes: azoreductase, 7 alpha-dehydroxylase, beta-glucuronidase, nitroreductase and urease activity; (ii) a global increase of short-chain fatty acids in faeces; (iii) an effect on pH and moisture of faeces, and (iv) also on aromatic compounds such as phenol, cresol, indole and skatol. The findings suggest that lactulose and lactitol are not comparable in their effect on the colonic microflora, its metabolism, and the consequent probiotic effects on human health. The differences found may also be of clinical relevance suggesting that neither compound is equipotent.

Long-term effects of Enterococcus faecium SF68 versus lactulose in the treatment of patients with cirrhosis and grade 1-2 hepatic encephalopathy

In 40 patients with cirrhosis on a dietary protein regimen of 1 g/kg b.w., we determined the effect on chronic hepatic encephalopathy of long-term administration of Enterococcus faecium (SF68) versus lactulose. The patients received one of the two treatments for three periods of 4 weeks, each separated by drug-free 2-week intervals. The efficacy of treatment was assessed by arterial blood ammonia concentration, mental status, number connection (Reitan's part A) test and flash-evoked visual potentials. At the end of the third period the reduction in both blood ammonia concentrations and Reitan's test times was more enhanced in patients on SF68 than in patients on lactulose. Furthermore, while patients on lactulose tended to return to basal values during drug-free intervals, responders in the SF68 group maintained improvement throughout the study. In conclusion, SF68 is at least as useful as lactulose for the chronic treatment of chronic hepatic encephalopathy; it has no adverse effects, and treatment can be interrupted for 2 weeks without losing the beneficial effects.

Hepatic disorders. Features and appropriate management

The spectrum of liver disease is extremely wide, with many of the underlying disorders having acute and chronic presentations. Most of the underlying pathogenetic mechanisms are accounted for by autoimmune disease, viral infection and toxic insult. The management strategy of any liver disease is a combination of treating the symptoms and complications that arise, as well as drug therapies relevant to the specific underlying diagnosis. Encephalopathy, ascites, spontaneous bacterial peritonitis, variceal bleeding and pruritus are the main complications at which drug therapy is directed, although in some cases it represents only 1 aspect of the overall management. Drug therapy per se is largely ineffective in acute liver failure with the possible exception of acetylcysteine, but many drugs are used in the management of the constituent components of this complex medical emergency. Treatments for specific liver conditions are expanding, especially in the areas of autoimmune and viral disease. The increasing availability and success of liver transplantation has tended to change the emphasis of management, and it is often not appropriate to exhaust the treatment options before referring the patient for transplantation. A comprehensive review of all liver disease is beyond the scope of this article, but hopefully the important principles of management and commonly occurring clinical decisions are discussed.

Rifaximin in the treatment of chronic hepatic encephalopathy

A study was performed to assess the efficacy and tolerability of rifaximin in the treatment of encephalopathy during cirrhosis of the liver. Fifty-five patients suffering from grade 1, 2 and 3 portosystemic encephalopathy, with a mean age of 58.9 years (range 30 to 86 years) were evaluated. The patients were treated for 15 consecutive days with rifaximin, an antibiotic which is not absorbed by the intestinal wall, at a dosage of 1200 mg/day in association with sufficient lactulose to induce 2 or 3 evacuations per day. Combined use of the 2 drugs proved an efficient means of controlling the majority of signs and symptoms. After just a few days, an improvement in the signs of encephalopathy was noted in all patients. The treatment was well tolerated and the patients completed the trial without any drug-related side-effects. The results of our trial, although in the context of an open assessment, confirm the clinical efficacy of rifaximin in association with a non-absorbable disaccharide such as lactulose. The 2 compounds have a synergetic effect in reducing ammonia-producing flora. Its efficacy and good tolerability make rifaximin a valid alternative to the use of aminoglycoside antibiotics associated with disaccharides in the treatment of patients with liver disease, particularly in the case of prolonged therapy.

Hepatic encephalopathy

The approach to the management of patients with HE is summarized in Table 3. Other diagnoses need to be excluded and, after a diagnosis of HE is made on clinical and possibly electroencephalographic grounds, a search made for precipitants. Sedatives and opiates should be avoided, and steps taken to avoid hypoglycaemia, fluid overload or electrolyte imbalance. Protein restriction should be instituted, and disaccharide such as lactitol or lactulose started. Neomycin may be added for more difficult cases for short duration. Branched chain amino acids should not be used routinely, but a trial of flumazenil may be justified for recalcitrant cases.

Lactitol in treatment of chronic hepatic encephalopathy. A meta-analysis

The efficacy and side effects of lactitol in the treatment of chronic hepatic encephalopathy was compared to that of other disaccharides in a meta-analysis of published randomized clinical trials (RCTs). The outcomes assessed were: (1) the rate of patients free from episodes of clinically detectable encephalopathy, and (2) the rate of patients free from one or more side effects in the different treatment groups. Four RCTs were eligible for analysis; in three lactitol was compared to lactulose, in one the alternative treatment was lactose in lactase-deficient patients. The methodological quality of these studies was high. Meta-analysis showed that lactitol was as effective as other disaccharides in the treatment of encephalopathy: pooled odds ratio was 0.83, 95% confidence interval was 0.38-1.82. Results were not sensitive to the use of alternative methods of counting and attributing events in these trials. Patients experienced fewer side effects during treatment with lactitol, but the pooled odds ratio was not statistically significant. In all studies lactitol was considered more palatable. Clinical effectiveness of lactitol, in long-term treatment of chronic encephalopathy, is similar to those of lactulose. It seems that lactitol has lower side effects than lactulose. Future RCTs with a double-blind design could be mainly aimed at evaluating the side-effect profile of the two disaccharides.