Jasmohan S. Bajaj

Hepatic encephalopathy in chronic liver disease: 2014 Practice Guideline by the American Association for the Study Of Liver Diseases and the European Association for the Study of the Liver

The AASLD/EASL Practice Guideline Subcommittee on Hepatic Encephalopathy are: Jayant A. Talwalkar (Chair, AASLD), Hari S. Conjeevaram, Michael Porayko, Raphael B. Merriman, Peter L.M. Jansen, and Fabien Zoulim. This guideline has been approved by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver and represents the position of both associations.

Altered profile of human gut microbiome is associated with cirrhosis and its complications

BACKGROUND & AIMS The gut microbiome is altered in cirrhosis; however its evolution with disease progression is only partly understood. We aimed to study changes in the microbiome over cirrhosis severity, its stability over time and its longitudinal alterations with decompensation. METHODS Controls and age-matched cirrhotics (compensated/decompensated/hospitalized) were included. Their stool microbiota was quantified using multi-tagged pyrosequencing. The ratio of autochthonous to non-autochthonous taxa was calculated as the cirrhosis dysbiosis ratio (CDR); a low number indicating dysbiosis. Firstly, the microbiome was compared between controls and cirrhotic sub-groups. Secondly, for stability assessment, stool collected twice within 6months in compensated outpatients was analyzed. Thirdly, changes after decompensation were assessed using (a) longitudinal comparison in patients before/after hepatic encephalopathy development (HE), (b) longitudinal cohort of hospitalized infected cirrhotics MELD-matched to uninfected cirrhotics followed for 30days. RESULTS 244 subjects [219 cirrhotics (121 compensated outpatients, 54 decompensated outpatients, 44 inpatients) and 25 age-matched controls] were included. CDR was highest in controls (2.05) followed by compensated (0.89), decompensated (0.66), and inpatients (0.32, p<0.0001) and negatively correlated with endotoxin. Microbiota and CDR remained unchanged in stable outpatient cirrhotics (0.91 vs. 0.86, p=0.45). In patients studied before/after HE development, dysbiosis occurred post-HE (CDR: 1.2 to 0.42, p=0.03). In the longitudinal matched-cohort, microbiota were significantly different between infected/uninfected cirrhotics at baseline and a low CDR was associated with death and organ failures within 30days. CONCLUSIONS Progressive changes in the gut microbiome accompany cirrhosis and become more severe in the setting of decompensation. The cirrhosis dysbiosis ratio may be a useful quantitative index to describe microbiome alterations accompanying cirrhosis progression.

Bile Acids and the Gut Microbiome

Purpose of review We examine the latest research on the emerging bile acid-gut microbiome axis and its role in health and disease. Our focus revolves around two key microbial pathways for degrading bile salts, and the impact of bile acid composition in the gut on the gut microbiome and host physiology. Recent findings Bile acid pool size has recently been shown to be a function of microbial metabolism of bile acids in the intestines. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. Bile acids are emerging as regulators of the gut microbiome at the highest taxonomic levels. The role of bile acids as hormones and potentiators of liver cancer is also emerging. Summary The host and microbiome appear to regulate bile acid pool size. The host produces a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of farnesoid X receptor (FXR) in intestine and liver. Members of the microbiome utilize bile acids and their conjugates resulting in agonism of FXR in intestine and liver resulting in a smaller, unconjugated hydrophobic bile acid pool. Hydrophilicity of the bile acid pool is associated with disease states. Reduced bile acid levels in the gut are associated with bacterial overgrowth and inflammation. Diet, antibiotic therapy, and disease states affect the balance of the microbiome-bile acid pool.

Linkage of gut microbiome with cognition in hepatic encephalopathy

Hepatic encephalopathy (HE) has been related to gut bacteria and inflammation in the setting of intestinal barrier dysfunction. We aimed to link the gut microbiome with cognition and inflammation in HE using a systems biology approach. Multitag pyrosequencing (MTPS) was performed on stool of cirrhotics and age-matched controls. Cirrhotics with/without HE underwent cognitive testing, inflammatory cytokines, and endotoxin analysis. Patients with HE were compared with those without HE using a correlation-network analysis. A select group of patients with HE (n = 7) on lactulose underwent stool MTPS before and after lactulose withdrawal over 14 days. Twenty-five patients [17 HE (all on lactulose, 6 also on rifaximin) and 8 without HE, age 56 ± 6 yr, model for end-stage liver disease score 16 ± 6] and ten controls were included. Fecal microbiota in cirrhotics were significantly different (higher Enterobacteriaceae, Alcaligeneceae, and Fusobacteriaceae and lower Ruminococcaceae and Lachnospiraceae) compared with controls. We found altered flora (higher Veillonellaceae), poor cognition, endotoxemia, and inflammation (IL-6, TNF-α, IL-2, and IL-13) in HE compared with cirrhotics without HE. In the cirrhosis group, Alcaligeneceae and Porphyromonadaceae were positively correlated with cognitive impairment. Fusobacteriaceae, Veillonellaceae, and Enterobacteriaceae were positively and Ruminococcaceae negatively related to inflammation. Network-analysis comparison showed robust correlations (all P < 1E-5) only in the HE group between the microbiome, cognition, and IL-23, IL-2, and IL-13. Lactulose withdrawal did not change the microbiome significantly beyond Fecalibacterium reduction. We concluded that cirrhosis, especially when complicated with HE, is associated with significant alterations in the stool microbiome compared with healthy individuals. Specific bacterial families (Alcaligeneceae, Porphyromonadaceae, Enterobacteriaceae) are strongly associated with cognition and inflammation in HE.

Spectrum of neurocognitive impairment in cirrhosis: Implications for the assessment of hepatic encephalopathy

Cirrhosis and chronic liver disease adversely affect neurocognitive functioning.1 These deficits range from neurological complications such as hepatic myelopathy to cognitive and mental status changes such as hepatic encephalopathy (HE).2 These neurocognitive difficulties can also severely restrict the patient’s functioning and result in morbidity and mortality.3-6 The most prominent neurocognitive complication of cirrhosis is HE, which reflects a spectrum of neuropsychiatric abnormalities seen in patients with liver dysfunction after exclusion of other known brain disease.7 The current system for studying HE is based on a subjective clinical classification largely based on mental status changes, the West Haven scale.2,7-9 In addition to the mental status changes detected by clinical scales such as the West Haven scale, there are significant neurocognitive disturbances in those with normal mental status, which is characterized by impaired neuropsychological and perceptual motor dysfunction.10 The current system of HE classification does not take into account the continuum of this neurocognitive dysfunction in HE, which forms a spectrum of neurocognitive impairment in cirrhosis (SONIC).7,11,12 This spectrum spans a patient’s performance from normal to overt HE to coma. The continuous nature of these impairments is supported by the presence of psychometric and neurophysiological impairments in patients even before they reach overt HE,13 poorer performance on tests in patients with treated overt HE than those without overt HE,1,14 and persistence of psychometric deficits even after adequate resolution of an episode of overt HE.15 In addition, the worse clinical outcomes in patients with poor psychometric performance as a continuous measure have also been described.16 This review focuses on the available techniques and systems for characterizing HE and discusses the need for an approach for gauging severity of early HE as a continuum based on relevant clinical outcomes. The overall neurological complications of cirrhosis can be HE-related or independent of HE, and it is important to review these separately.

Minimal hepatic encephalopathy is associated with motor vehicle crashes: the reality beyond the driving test.

Patients with minimal hepatic encephalopathy (MHE) have impaired driving skills, but association of MHE with motor vehicle crashes is unclear. Standard psychometric tests (SPT) or inhibitory control test (ICT) can be used to diagnose MHE. The aim was to determine the association of MHE with crashes and traffic violations over the preceding year and on 1‐year follow‐up. Patients with cirrhosis were diagnosed with MHE by ICT (MHEICT) and SPT (MHESPT). Self and department‐of‐transportation (DOT)‐reports were used to determine crashes and violations over the preceding year. Agreement between self and DOT‐reports was analyzed. Patients then underwent 1‐year follow‐up for crash/violation occurrence. Crashes in those with/without MHEICT and MHESPT were compared. 167 patients with cirrhosis had DOT‐reports, of which 120 also had self‐reports. A significantly higher proportion of MHEICT patients with cirrhosis experienced crashes in the preceding year compared to those without MHE by self‐report (17% vs 0.0%, P = 0.0004) and DOT‐reports (17% vs 3%, P = 0.004, relative risk: 5.77). SPT did not differentiate between those with/without crashes. A significantly higher proportion of patients with crashes had MHEICT compared to MHESPT, both self‐reported (100% vs 50%, P = 0.03) and DOT‐reported (89% vs 44%, P = 0.01). There was excellent agreement between self and DOT‐reports for crashes and violations (Kappa 0.90 and 0.80). 109 patients were followed prospectively. MHEICT patients had a significantly higher future crashes/violations compared to those without (22% vs 7%, P = 0.03) but MHESPT did not. MHEICT (Odds ratio: 4.51) and prior year crash/violation (Odds ratio: 2.96) were significantly associated with future crash/violation occurrence. Conclusion: Patients with cirrhosis and MHEICT have a significantly higher crash rate over the preceding year and on prospective follow‐up compared to patients without MHE. ICT, but not SPT performance is significantly associated with prior and future crashes and violations. There was an excellent agreement between self‐ and DOT‐reports. (HEPATOLOGY 2009.)

Modulation of the fecal bile acid profile by gut microbiota in cirrhosis.

BACKGROUND & AIMS The 7α-dehydroxylation of primary bile acids (BAs), chenodeoxycholic (CDCA) and cholic acid (CA) into the secondary BAs, lithocholic (LCA) and deoxycholic acid (DCA), is a key function of the gut microbiota. We aimed at studying the linkage between fecal BAs and gut microbiota in cirrhosis since this could help understand cirrhosis progression. METHODS Fecal microbiota were analyzed by culture-independent multitagged-pyrosequencing, fecal BAs using HPLC and serum BAs using LC-MS in controls, early (Child A) and advanced cirrhotics (Child B/C). A subgroup of early cirrhotics underwent BA and microbiota analysis before/after eight weeks of rifaximin. RESULTS Cross-sectional: 47 cirrhotics (24 advanced) and 14 controls were included. In feces, advanced cirrhotics had the lowest total, secondary, secondary/primary BA ratios, and the highest primary BAs compared to early cirrhotics and controls. Secondary fecal BAs were detectable in all controls but in a significantly lower proportion of cirrhotics (p<0.002). Serum primary BAs were higher in advanced cirrhotics compared to the rest. Cirrhotics, compared to controls, had a higher Enterobacteriaceae (potentially pathogenic) but lower Lachonospiraceae, Ruminococcaceae and Blautia (7α-dehydroxylating bacteria) abundance. CDCA was positively correlated with Enterobacteriaceae (r=0.57, p<0.008) while Ruminococcaceae were positively correlated with DCA (r=0.4, p<0.05). A positive correlation between Ruminococcaceae and DCA/CA (r=0.82, p<0.012) and Blautia with LCA/CDCA (r=0.61, p<0.03) was also seen. Prospective study: post-rifaximin, six early cirrhotics had reduction in Veillonellaceae and in secondary/primary BA ratios. CONCLUSIONS Cirrhosis, especially advanced disease, is associated with a decreased conversion of primary to secondary fecal BAs, which is linked to abundance of key gut microbiome taxa.

Probiotic Yogurt for the Treatment of Minimal Hepatic Encephalopathy

OBJECTIVES:Minimal hepatic encephalopathy (MHE), the preclinical stage of overt hepatic encephalopathy (OHE), is a significant condition affecting up to 60% of cirrhotics. All MHE therapies modify gut microflora, but consensus regarding MHE treatment and long-term adherence studies is lacking. The aim was to determine the effect of probiotic supplementation in the form of a food item, probiotic yogurt, on MHE reversal and adherence.METHODS:Nonalcoholic MHE cirrhotics (defined by a standard psychometric battery) were randomized with unblinded allocation to receive probiotic yogurt (with proven culture stability) or no treatment (no Rx) for 60 days in a 2:1 ratio. Quality of life (short form [SF]-36), adherence, venous ammonia, model of end-stage liver disease (MELD) scores, and inflammatory markers (tumor necrosis factor [TNF]-α, interleukin [IL]-6) were also measured. Outcomes were MHE reversal using blinded scoring, OHE development, and adherence.RESULTS:Twenty-five patients (17 yogurt, 8 no Rx; 84% Child class A) were enrolled. A significantly higher percentage of yogurt patients reversed MHE compared to no Rx patients (71% vs 0%, P= 0.003, intention-to-treat). Yogurt patients demonstrated a significant improvement in number connection test-A (NCT-A), block design test (BDT), and digit symbol test (DST) compared to baseline/no Rx group. Twenty-five percent of no Rx versus 0% of yogurt patients developed OHE during the trial. Eighty-eight percent of yogurt patients were adherent. No adverse effects or change in covariates were observed. All patients who completed the yogurt arm were agreeable to continue yogurt for 6 months if needed.CONCLUSIONS:This trial demonstrated a significant rate of MHE reversal and excellent adherence in cirrhotics after probiotic yogurt supplementation with potential for long-term adherence.

Review article: the design of clinical trials in hepatic encephalopathy - an International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) consensus statement

Aliment Pharmacol Ther 2011; 33: 739–747

Modulation of the Metabiome by Rifaximin in Patients with Cirrhosis and Minimal Hepatic Encephalopathy

Hepatic encephalopathy (HE) represents a dysfunctional gut-liver-brain axis in cirrhosis which can negatively impact outcomes. This altered gut-brain relationship has been treated using gut-selective antibiotics such as rifaximin, that improve cognitive function in HE, especially its subclinical form, minimal HE (MHE). However, the precise mechanism of the action of rifaximin in MHE is unclear. We hypothesized that modulation of gut microbiota and their end-products by rifaximin would affect the gut-brain axis and improve cognitive performance in cirrhosis. Aim To perform a systems biology analysis of the microbiome, metabolome and cognitive change after rifaximin in MHE. Methods Twenty cirrhotics with MHE underwent cognitive testing, endotoxin analysis, urine/serum metabolomics (GC and LC-MS) and fecal microbiome assessment (multi-tagged pyrosequencing) at baseline and 8 weeks post-rifaximin 550 mg BID. Changes in cognition, endotoxin, serum/urine metabolites (and microbiome were analyzed using recommended systems biology techniques. Specifically, correlation networks between microbiota and metabolome were analyzed before and after rifaximin. Results There was a significant improvement in cognition(six of seven tests improved,p<0.01) and endotoxemia (0.55 to 0.48 Eu/ml, p = 0.02) after rifaximin. There was a significant increase in serum saturated (myristic, caprylic, palmitic, palmitoleic, oleic and eicosanoic) and unsaturated (linoleic, linolenic, gamma-linolenic and arachnidonic) fatty acids post-rifaximin. No significant microbial change apart from a modest decrease in Veillonellaceae and increase in Eubacteriaceae was observed. Rifaximin resulted in a significant reduction in network connectivity and clustering on the correlation networks. The networks centered on Enterobacteriaceae, Porphyromonadaceae and Bacteroidaceae indicated a shift from pathogenic to beneficial metabolite linkages and better cognition while those centered on autochthonous taxa remained similar. Conclusions Rifaximin is associated with improved cognitive function and endotoxemia in MHE, which is accompanied by alteration of gut bacterial linkages with metabolites without significant change in microbial abundance. Trial Registration ClinicalTrials.gov NCT01069133