Impaired Gut-Liver-Brain Axis in Patients with Cirrhosis. Sci Rep. 2016;6:26800. [PMID: 27225869 PMCID: PMC4880966 DOI: 10.1038/srep26800]

Gut microbial composition in patients with psoriasis

Since the last 5–10 years the relevance of the gut microbiome on different intestinal illnesses has been revealed. Recent findings indicate the effect of gut microbiome on certain dermatological diseases such as atopic dermatitis. However, data on other skin diseases such as psoriasis are limited. This is the first time attempting to reveal the gut microbiome composition of psoriatic patients with a prospective study including a group of patients with plaque psoriasis, analyzing their gut microbiome and the relationship between the microbiome composition and bacterial translocation. The microbiome of a cohort of 52 psoriatic patients (PASI score ≥6) was obtained by 16s rRNA massive sequencing with MiSeq platform (Illumina inc, San Diego) with an average of 85,000 sequences per sample. The study of the gut microbiome and enterotype shows from the first time a specific “psoriatic core intestinal microbiome” that clearly differs from the one present in healthy population. In addition, those psoriatic patients classified as belonging to enterotype 2 tended to experience more frequent bacterial translocation and higher inflammatory status (71%) than patients with other enterotypes (16% for enterotype 1; and 21% for enterotype 3).

Gut : liver : brain axis: the microbial challenge in the hepatic encephalopathy

Hepatic encephalopathy (HE) is a debilitating neuropsychiatric condition often associated with acute liver failure or cirrhosis. Advanced liver diseases are characterized by a leaky gut and systemic inflammation. There is strong evidence that the pathogenesis of HE is linked to a dysbiotic gut microbiota and to harmful microbial by-products, such as ammonia, indoles, oxindoles and endotoxins. Increased concentrations of these toxic metabolites together with the inability of the diseased liver to clear such products is thought to play an important patho-ethiological role. Current first line clinical treatments target microbiota dysbiosis by decreasing the counts of pathogenic bacteria, blood endotoxemia and ammonia levels. This review will focus on the role of the gut microbiota and its metabolism in HE and advanced cirrhosis. It will critically assess data from different clinical trials measuring the efficacy of the prebiotic lactulose, the probiotic VSL#3 and the antibiotic rifaximin in treating HE and advanced cirrhosis, through gut microbiota modulation. Additionally data from Randomised Controlled Trials using pre-, pro- and synbiotic will be also considered by reporting meta-analysis studies. The large amount of existing data showed that HE is a clear example of how an altered gut microbiota homeostasis can influence and impact on physiological functions outside the intestine, with implication for host health at the systems level. Nevertheless, a strong effort should be made to increase the information on gut microbiota ecology and its metabolic function in liver diseases and HE.

Toll-like receptor 4 polymorphisms and bacterial infections in patients with cirrhosis and ascites

AIM

To assess the relationship between the presence of toll-like receptor 4 (TLR4) polymorphisms and bacterial infections in cirrhotic patients with ascites.

METHODS

We prospectively included consecutive patients with cirrhosis and ascites hospitalized during a 6-year period. Patients with human immunodeficiency virus (HIV) infection or any other immunodeficiency, patients with advanced hepatocellular carcinoma (beyond Milan's criteria) or any other condition determining poor short-term prognosis, and patients with a permanent urinary catheter were excluded. The presence of D299G and/or T399I TLR4 polymorphisms was determined by sequencing and related to the incidence and probability of bacterial infections, other complications of cirrhosis, hepatocellular carcinoma, and mortality during follow-up. A multivariate analysis to identify predictive variables of mortality in the whole series was performed.

RESULTS

We included 258 patients: 28 (10.8%) were carriers of D299G and/or T399I TLR4 polymorphisms (polymorphism group) and 230 patients were not (wild-type group). The probability of developing any bacterial infection at one-year follow-up was 78% in the polymorphism group and 69% in the wild-type group (P = 0.54). The one-year probability of presenting infections caused by gram-negative bacilli (51% vs 44%, P = 0.68), infections caused by gram-positive cocci (49% vs 40%, P = 0.53), and spontaneous bacterial peritonitis (29% vs 34%, respectively, P = 0.99) did not differ between the two groups. The one-year probability of transplant-free survival was 55% in the polymorphism group and 66% in the wild-type group (P = 0.15). Multivariate analysis confirmed that age, Child-Pugh score, active alcohol intake, previous hepatic encephalopathy, hepatocellular carcinoma and serum creatinine were associated with a higher risk of death during follow-up.

CONCLUSION

Genetic polymorphisms D299G and/or T399I of TLR4 do not seem to play a relevant role in the predisposition of cirrhotic patients with ascites to bacterial infections.

Rifaximin ameliorates hepatic encephalopathy and endotoxemia without affecting the gut microbiome diversity

AIM

To determine the efficacy of rifaximin for hepatic encephalopathy (HE) with the linkage of gut microbiome in decompensated cirrhotic patients.

METHODS

Twenty patients (12 men and 8 women; median age, 66.8 years; range, 46-81 years) with decompensated cirrhosis (Child-pugh score > 7) underwent cognitive neuropsychological testing, endotoxin analysis, and fecal microbiome assessment at baseline and after 4 wk of treatment with rifaximin 400 mg thrice a day. HE was determined by serum ammonia level and number connection test (NCT)-A. Changes in whole blood endotoxin activity (EA) was analyzed by endotoxin activity assay. Fecal microbiome was assessed by 16S ribosome RNA (rRNA) gene sequencing.

RESULTS

Treatment with rifaximin for 4 wk improved hyperammonemia (from 90.6 ± 23.9 μg/dL to 73.1 ± 33.1 μg/dL; P < 0.05) and time required for NCT (from 68.2 ± 17.4 s to 54.9 ± 20.3 s; P < 0.05) in patients who had higher levels at baseline. Endotoxin activity was reduced (from 0.43 ± 0.03 to 0.32 ± 0.09; P < 0.05) in direct correlation with decrease in serum ammonia levels (r = 0.5886, P < 0.05). No statistically significant differences were observed in the diversity estimator (Shannon diversity index) and major components of the gut microbiome between the baseline and after treatment groups (3.948 ± 0.548 at baseline vs 3.980 ± 0.968 after treatment; P = 0.544), but the relative abundances of genus Veillonella and Streptococcus were lowered.

CONCLUSION

Rifaximin significantly improved cognition and reduced endotoxin activity without significantly affecting the composition of the gut microbiome in patients with decompensated cirrhosis.

Overt hepatic encephalopathy impairs learning on the EncephalApp stroop which is reversible after liver transplantation

After an initial exposure, patients can develop test-taking/learning strategies called the "test sophistication effect." Patients with cirrhosis with prior overt hepatic encephalopathy (OHE) could have persistent learning impairments. The aim was to define learning/test sophistication on EncephalApp (downloadable application) in OHE patients compared with patients without prior overt hepatic encephalopathy (no-OHE) patients and controls cross-sectionally and longitudinally. The EncephalApp Stroop App consists of 2 sections: the easier "Off" run assesses psychomotor speed while the difficult "On" run assesses cognitive flexibility. For the cross-sectional analysis, outpatients with cirrhosis with/without controlled OHE and healthy controls underwent EncephalApp testing, which requires 5 Off and 5 On runs. We studied the difference in time required between completing trial 1 compared with trial 5 (delta 1-5) in both the On and Off runs in controls, all patients with cirrhosis, and between prior OHE/no-OHE patients with cirrhosis. For the longitudinal analyses, 2 groups of patients with cirrhosis were studied; 1 was administered the EncephalApp ≥ 2 weeks apart, and the second was administered before and 6 months after liver transplantation. The study included 89 controls and 230 patients with cirrhosis (85 prior OHE; Model for End-Stage Liver Disease, 11) with similar age (64 versus 61 years; P = 0.92). Patients with cirrhosis had impaired EncephalApp total times and impaired learning on the On runs compared with controls. OHE patients had worse EncephalApp times and learning with the On runs compared with no-OHE patients, which persisted in the longitudinal cohort. No differences in learning were seen in the Off runs. After transplant, there was restoration of learning capability with the On runs in the OHE patients. In conclusion, cognitive flexibility tested by the EncephalApp On runs improves over time in healthy controls and no-OHE but not prior OHE. Psychomotor speed remains similar over time. The learning impairment manifested by patients with cirrhosis with OHE is restored after transplant. Liver Transplantation 23 1396-1403 2017 AASLD.

Fecal microbiota transplantation prevents hepatic encephalopathy in rats with carbon tetrachloride-induced acute hepatic dysfunction

AIM

To investigate whether fecal microbiota transplantation (FMT) prevents hepatic encephalopathy (HE) in rats with carbon tetrachloride (CCl₄)-induced acute hepatic dysfunction.

METHODS

A rat model of HE was established with CCl₄. Rat behaviors and spatial learning capability were observed, and hepatic necrosis, intestinal mucosal barrier, serum ammonia levels and intestinal permeability were determined in HE rats receiving FMT treatment. Furthermore, the expression of tight junction proteins (Claudin-1, Claudin-6 and Occludin), Toll-like receptor (TLR) 4/TLR9, interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α was examined.

RESULTS

FMT improved rat behaviors, HE grade and spatial learning capability. Moreover, FMT prevented hepatic necrosis and intestinal mucosal barrier damage, leading to hepatic clearance of serum ammonia levels and reduced intestinal permeability. The expression of TLR4 and TLR9, two potent mediators of inflammatory response, was significantly downregulated in the liver of rats treated with FMT. Consistently, circulating pro-inflammatory factors such as interleukin (IL)-1β, IL-6 and tumor necrosis factor-α were remarkably decreased, indicating that FMT is able to limit systemic inflammation by decreasing the expression of TLR4 and TLR9. Importantly, HE-induced loss of tight junction proteins (Claudin-1, Claudin-6 and Occludin) was restored in intestinal tissues of rats receiving FMT treatment.

CONCLUSION

FMT enables protective effects in HE rats, and it improves the cognitive function and reduces the liver function indexes. FMT may cure HE by altering the intestinal permeability and improving the TLR response of the liver.

Microbiota, cirrhosis, and the emerging oral-gut-liver axis

Cirrhosis is a prevalent cause of morbidity and mortality, especially for those at an advanced decompensated stage. Cirrhosis development and progression involves several important interorgan communications, and recently, the gut microbiome has been implicated in pathophysiology of the disease. Dysbiosis, defined as a pathological change in the microbiome, has a variable effect on the compensated versus decompensated stage of cirrhosis. Adverse microbial changes, both in composition and function, can act at several levels within the gut (stool and mucosal) and have also been described in the blood and oral cavity. While dysbiosis in the oral cavity could be a source of systemic inflammation, current cirrhosis treatment modalities are targeted toward the gut-liver axis and do not address the oral microbiome. As interventions designed to modulate oral dysbiosis may delay progression of cirrhosis, a better understanding of this process is of the utmost importance. The concept of oral microbiota dysbiosis in cirrhosis is relatively new; therefore, this review will highlight the emerging role of the oral-gut-liver axis and introduce perspectives for future research.

Gut Microbiome-based Therapeutics in Liver Cirrhosis: Basic Consideration for the Next Step

Infections account for significant morbidity and mortality in liver cirrhosis and most are related to the gut microbiome. Fecal dysbiosis, characterized by an overgrowth of potentially pathogenic bacteria and a decrease in autochthonous non-pathogenic bacteria, becomes prominent with the progression of liver cirrhosis. In cirrhotic patients, disruption of the intestinal barrier causes intestinal hyperpermeability (i.e. leaky gut), which is closely related to gut dysmotility, dysbiosis and small intestinal bacterial overgrowth and may induce pathological bacterial translocation. Although the involved microbial taxa are somewhat different between the cirrhotic patients from the East and the West, the common manifestation of a shortage of bacteria that contribute to the production of short-chain fatty acids and secondary bile acids may facilitate intestinal inflammation, leaky gut and gut dysbiosis. Translocated endotoxin and bacterial DNA are capable of provoking potent inflammation and affecting the metabolic and hemodynamic systems, which may ultimately enhance the progression of liver cirrhosis and its various complications, such as hepatic encephalopathy (HE), variceal bleeding, infection and renal disturbances. Among studies on the microbiome-based therapeutics, findings of probiotic effects on HE have been contradictory in spite of several supportive results. However, the effects of synbiotics and prebiotics are substantially documented. The background of their effectiveness should be evaluated again in relation to the cirrhosis-related changes in gut microbiome and their metabolic effects. Strict indications for the antibiotic rifaximin remain unestablished, although its effect is promising, improving HE and other complications with little influence on microbial populations. The final goal of microbiome-based therapeutics is to adjust the gut-liver axis to the maximal benefit of cirrhotic patients, with the aid of evolving metagenomic and metabolomic analyses.

A Comprehensive Review of Bioelectrical Impedance Analysis and Other Methods in the Assessment of Nutritional Status in Patients with Liver Cirrhosis

It is assumed that approximately 24-66% of patients with liver cirrhosis develop malnutrition. Numerous pathological processes lead to serious disorders of nutritional status in this group of patients. Malnutrition in the course of liver cirrhosis is associated with increased morbidity, complications, and low quality of life. Under these conditions, detection of malnutrition is of crucial importance. This review explores the complex mechanisms that lead to malnutrition in the course of liver cirrhosis and focuses on methods used in the assessment of nutritional status in cirrhotic patients. Among others, the role of bioelectrical impedance is highlighted. This noninvasive tool is promising and quite an accurate method of estimating body composition.

Administration of Lactobacillus salivarius LI01 or Pediococcus pentosaceus LI05 prevents CCl4-induced liver cirrhosis by protecting the intestinal barrier in rats

Alterations in the gut microbiome have been reported in liver cirrhosis, and probiotic interventions are considered a potential treatment strategy. This study aimed to evaluate the effects and mechanisms of Lactobacillus salivarius LI01, Pediococcus pentosaceus LI05, Lactobacillus rhamnosus GG, Clostridium butyricum MIYAIRI and Bacillus licheniformis Zhengchangsheng on CCl₄-induced cirrhotic rats. Only administration of LI01 or LI05 prevented liver fibrosis and down-regulated the hepatic expression of profibrogenic genes. Serum endotoxins, bacterial translocations (BTs), and destruction of intestinal mucosal ultrastructure were reduced in rats treated with LI01 or LI05, indicating maintenance of the gut barrier as a mechanism; this was further confirmed by the reduction of not only hepatic inflammatory cytokines, such as TNF-α, IL-6, and IL-17A, but also hepatic TLR2, TLR4, TLR5 and TLR9. Metagenomic sequencing of 16S rRNA gene showed an increase in potential beneficial bacteria, such as Elusimicrobium and Prevotella, and a decrease in pathogenic bacteria, such as Escherichia. These alterations in gut microbiome were correlated with profibrogenic genes, gut barrier markers and inflammatory cytokines. In conclusion, L. salivarius LI01 and P. pentosaceus LI05 attenuated liver fibrosis by protecting the intestinal barrier and promoting microbiome health. These results suggest novel strategies for the prevention of liver cirrhosis.

Liver transplant modulates gut microbial dysbiosis and cognitive function in cirrhosis

Liver transplantation (LT) improves daily function and cognition in patients with cirrhosis, but a subset of patients can remain impaired. Unfavorable microbiota or dysbiosis is observed in patients with cirrhosis, but the effect of LT on microbial composition, especially with poor post-LT cognition, is unclear. The aims were to determine the effect of LT on gut microbiota and to determine whether gut microbiota are associated with cognitive dysfunction after LT. We enrolled outpatient patients with cirrhosis on the LT list and followed them until 6 months after LT. Cognition (Psychometric Hepatic Encephalopathy score [PHES]), health-related quality of life (HRQOL), and stool microbiota (multitagged sequencing for diversity and taxa) tests were performed at both visits. Persistent cognitive impairment was defined as a stable/worsening PHES. Both pre-/post-LT data were compared with age-matched healthy controls. We enrolled 45 patients (56 ± 7 years, Model for End-Stage Liver Disease score 26 ± 8). They received LT 6 ± 3 months after enrollment and were re-evaluated 7 ± 2 months after LT with a stable course. A significantly improved HRQOL, PHES, with increase in microbial diversity, increase in autochthonous, and decrease in potentially pathogenic taxa were seen after LT compared with baseline. However, there was continued dysbiosis and HRQOL/cognitive impairment after LT compared with controls in 29% who did not improve PHES after LT. In these, Proteobacteria relative abundance was significantly higher and Firmicutes were lower after LT, whereas the reverse occurred in the group that improved. Delta PHES was negatively correlated with delta Proteobacteria and positively with delta Firmicutes. In conclusion, LT improves gut microbiota diversity and dysbiosis compared with pre-LT baseline but residual dysbiosis remains compared with controls. There is cognitive and HRQOL enhancement in general after LT, but a higher Proteobacteria relative abundance change is associated with posttransplant cognitive impairment. Liver Transplantation 23 907-914 2017 AASLD.

The microbiome and hepatobiliary-pancreatic cancers

The human intestinal microbiome encompasses at least 100 trillion microorganisms that can influence host immunity and disease conditions, including cancer. Hepatobiliary and pancreatic cancers have been associated with poor prognosis owing to their high level of tumor invasiveness, distant metastasis, and resistance to conventional treatment options, such as chemotherapy. Accumulating evidence from animal models suggests that specific microbes and microbial dysbiosis can potentiate hepatobiliary-pancreatic tumor development by damaging DNA, activating oncogenic signaling pathways, and producing tumor-promoting metabolites. Emerging evidence suggests that the gut microbiota may influence not only the efficacy of cancer chemotherapies and novel targeted immunotherapies such as anti-CTLA4 and anti-CD274 therapies but also the occurrence of postoperative complications after hepatobiliary and pancreatic surgery, which have been associated with tumor recurrence and worse patient survival in hepatobiliary-pancreatic cancers. Hence, a better understanding of roles of the gut microbiota in the development and progression of hepatobiliary-pancreatic tumors may open opportunities to develop new prevention and treatment strategies for patients with hepatobiliary-pancreatic cancer through manipulating the gut microbiota by diet, lifestyle, antibiotics, and pro- and prebiotics.

The gut microbiota: A new potential driving force in liver cirrhosis and hepatocellular carcinoma

The gut microbiota has recently been recognized as a major environmental factor in the pathophysiology of many human diseases. The anatomical and function connection existing between gut and liver provides the theoretical basis to assume the liver is a major target for gut microbes. In the last decades, numerous studies reported an altered composition of gut microbiota in patients with liver cirrhosis and a progressively marked dysbiosis with worsening of the liver disease. The risk of developing hepatocellular carcinoma, the deadliest complication of liver cirrhosis, is widely variable among cirrhotic patients, thus suggesting a complexity of genetic and environmental factors implicated in hepatocarcinogenesis. Gut microbiota is now emerging as a plausible candidate to explain this variability. In this manuscript we review the human and the experimental evidence supporting the potential implication of gut microbiota in the promotion, progression and complication of liver disease.

Longitudinal Analysis of the Intestinal Microbiota in Liver Transplantation

BACKGROUND

Increasing evidence suggests that the intestinal microbiota plays an important role in liver diseases. However, the dynamics of the intestinal microbiota during liver transplantation (LT) and its potential role in clinical course remain unknown.

METHODS

We prospectively analyzed the intestinal microbiota of 38 patients who underwent LT in Kyoto University Hospital. We characterized the microbial compositions of fecal specimens from LT patients using a metagenomics approach by an Illumina MiSeq platform. We analyzed the diversity of microbiota sequentially from pretransplantation until 2 months after LT and also compared the microbiota during an episode of acute cellular rejection (ACR) and bloodstream infections (BSI) to the microbial composition of time-matched fecal specimens obtained from patients who did not experience ACR or BSI, respectively.

RESULTS

Three hundred twenty fecal specimens were analyzed. Dynamic changes were observed in the microbial composition of LT recipients during the perioperative period. Over the course of LT, the mean diversity index decreased during the first 3 weeks after LT and gradually increased during our observation period. The loss of intestinal microbiota diversity was associated with high Child-Pugh scores, high model for end-stage liver disease scores, ACR, and BSI. At the family level, Bacteroides, Enterobacteriaceae, Streptococcaceae, and Bifidobacteriaceae were increased whereas Enterococcaceae, Lactobacillaceae, Clostridiaceae, Ruminococcaceae, and Peptostreptococcaceae were decreased in ACR patients.

CONCLUSIONS

The microbiota of LT patients was associated with the severity of liver diseases and the presence of ACR and BSI. These results lay the groundwork for more comprehensive investigations of microbiota characteristics to identify diagnostic markers for transplant health and to guide intervention strategies to improve transplant outcomes.

Gut Microbiota and Complications of Liver Disease

Chronic liver disease, cirrhosis, and its complications are epidemic worldwide. Most complications are mediated through a dysfunctional gut-liver axis. New techniques have made culture-independent analysis of the gut microbiome widespread. With insight into an unfavorable microbiome (dysbiosis) and how it affects liver disease, investigators have discovered new targets to potentially improve outcomes. Dysbiosis is associated with endotoxemia and propagates liver injury due to nonalcoholic steatohepatitis and alcohol. The composition and functionality of the microbiome changes with the development of cirrhosis, decompensation, and with treatments for these conditions. Gut microbiota can be used to predict clinically relevant outcomes in cirrhosis.

Brain Training with Video Games in Covert Hepatic Encephalopathy

Despite the associated adverse outcomes, pharmacologic intervention for covert hepatic encephalopathy (CHE) is not the standard of care. We hypothesized that a video game-based rehabilitation program would improve white matter integrity and brain connectivity in the visuospatial network on brain magnetic resonance imaging (MRI), resulting in improved cognitive function in CHE subjects on measures consistent with the cognitive skill set emphasized by the two video games (e.g., IQ Boost-visual working memory, and Aim and Fire Challenge-psychomotor speed), but also generalize to thinking skills beyond the focus of the cognitive training (Hopkins verbal learning test (HVLT)-verbal learning/memory) and improve their health-related quality of life (HRQOL). The trial included three phases over 8 weeks; during the learning phase (cognitive tests administered twice over 2 weeks without intervening intervention), training phase (daily video game training for 4 weeks), and post-training phase (testing 2 weeks after the video game training ended). Thirty CHE patients completed all visits with significant daily achievement on the video games. In a subset of 13 subjects that underwent brain MRI, there was a significant decrease in fractional anisotropy, and increased radial diffusivity (suggesting axonal sprouting or increased cross-fiber formation) involving similar brain regions (i.e., corpus callosum, internal capsule, and sections of the corticospinal tract) and improvement in the visuospatial resting-state connectivity corresponding to the video game training domains. No significant corresponding improvement in HRQOL or HVLT performance was noted, but cognitive performance did transiently improve on cognitive tests similar to the video games during training. Although multimodal brain imaging changes suggest reductions in tract edema and improved neural network connectivity, this trial of video game brain training did not improve the HRQOL or produce lasting improvement in cognitive function in patients with CHE.

Gut to Brain Dysbiosis: Mechanisms Linking Western Diet Consumption, the Microbiome, and Cognitive Impairment

Consumption of a Western Diet (WD) that is high in saturated fat and added sugars negatively impacts cognitive function, particularly mnemonic processes that rely on the integrity of the hippocampus. Emerging evidence suggests that the gut microbiome influences cognitive function via the gut-brain axis, and that WD factors significantly alter the proportions of commensal bacteria in the gastrointestinal tract. Here we review mechanisms through which consuming a WD negatively impacts neurocognitive function, with a particular focus on recent evidence linking the gut microbiome with dietary- and metabolic-associated hippocampal impairment. We highlight evidence linking gut bacteria to altered intestinal permeability and blood brain barrier integrity, thus making the brain more vulnerable to the influx of deleterious substances from the circulation. WD consumption also increases production of endotoxin by commensal bacteria, which may promote neuroinflammation and cognitive dysfunction. Recent findings also show that diet-induced alterations in gut microbiota impair peripheral insulin sensitivity, which is associated with hippocampal neuronal derrangements and associated mnemonic deficits. In some cases treatment with specific probiotics or prebiotics can prevent or reverse some of the deleterious impact of WD consumption on neuropsychological outcomes, indicating that targeting the microbiome may be a successful strategy for combating dietary- and metabolic-associated cognitive impairment.

Elderly patients have an altered gut-brain axis regardless of the presence of cirrhosis

Cognitive difficulties manifested by the growing elderly population with cirrhosis could be amnestic (memory-related) or non-amnestic (memory-unrelated). The underlying neuro-biological and gut-brain changes are unclear in this population. We aimed to define gut-brain axis alterations in elderly cirrhotics compared to non-cirrhotic individuals based on presence of cirrhosis and on neuropsychological performance. Age-matched outpatients with/without cirrhosis underwent cognitive testing (amnestic/non-amnestic domains), quality of life (HRQOL), multi-modal MRI (fMRI go/no-go task, volumetry and MR spectroscopy), blood (inflammatory cytokines) and stool collection (for microbiota). Groups were studied based on cirrhosis/not and also based on neuropsychological performance (amnestic-type, amnestic/non-amnestic-type and unimpaired). Cirrhotics were impaired on non-amnestic and selected amnestic tests, HRQOL and systemic inflammation compared to non-cirrhotics. Cirrhotics demonstrated significant changes on MR spectroscopy but not on fMRI or volumetry. Correlation networks showed that Lactobacillales members were positively while Enterobacteriaceae and Porphyromonadaceae were negatively linked with cognition. Using the neuropsychological classification amnestic/non-amnestic-type individuals were majority cirrhosis and had worse HRQOL, higher inflammation and decreased autochthonous taxa relative abundance compared to the rest. This classification also predicted fMRI, MR spectroscopy and volumetry changes between groups. We conclude that gut-brain axis alterations may be associated with the type of neurobehavioral decline or inflamm-aging in elderly cirrhotic subjects.

Gut microbiome and liver diseases

The gut microbiota has recently evolved as a new important player in the pathophysiology of many intestinal and extraintestinal diseases. The liver is the organ which is in closest contact with the intestinal tract, and is exposed to a substantial amount of bacterial components and metabolites. Various liver disorders such as alcoholic liver disease, non-alcoholic liver disease and primary sclerosing cholangitis have been associated with an altered microbiome. This dysbiosis may influence the degree of hepatic steatosis, inflammation and fibrosis through multiple interactions with the host's immune system and other cell types. Whereas few results from clinical metagenomic studies in liver disease are available, evidence is accumulating that in liver cirrhosis an oral microbiome is overrepresented in the lower intestinal tract, potentially contributing to disease process and severity. A major role for the gut microbiota in liver disorders is also supported by the accumulating evidence that several complications of severe liver disease such as hepatic encephalopathy are efficiently treated by various prebiotics, probiotics and antibiotics. A better understanding of the gut microbiota and its components in liver diseases might provide a more complete picture of these complex disorders and also form the basis for novel therapies.

Community-Metabolome Correlations of Gut Microbiota from Child-Turcotte-Pugh of A and B Patients

The gut flora are widely involved in the cometabolism with the host and have evident effects on the metabolic phenotype of host. This study performed a metabolome analysis of the intestinal microbiota specific for liver cirrhosis. The study population included patients with Child-Turcotte-Pugh score of A (AP, n = 5) and B (BP, n = 5), and control subjects (NM, n = 3). Metagenomic DNA from fecal microbiota was extracted followed by metagenomic sequencing through Illumina MiSeq high throughput sequencing of 16S rRNA regions. The detection of metabolites from fecal samples was performed using high-performance liquid phase chromatography and gas chromatography coupled with tandem mass spectrometry. Intestinal microbiota community and metabolite analysis both showed separation of cirrhotic patients from control participants, moreover, the microbiota–metabolite correlations changed in cirrhotic patients. Fecal microbiota from cirrhotic patients, with the reduced diversity, contained a decreased abundance of Bacteroidetes and an increased abundance of Firmicutes and Proteobacteria compared with the normal samples. Analysis of metabolome revealed a remarkable change in the metabolic potential of the microbiota in cirrhotic patients, with specific higher concentrations of amine, unsaturated fatty acid, and short-chain fatty acids, and lower concentrations of sugar alcohol and amino acid, suggesting the initial equilibrium of gut microbiota community and co-metabolism with the host were perturbed by cirrhosis. Our study illustrated the relationship between fecal microbiota composition and metabolome in cirrhotic patients, which may improve the clinical prognosis of cirrhosis.