Translocated intestinal bacteria cause spontaneous bacterial peritonitis in cirrhotic rats: molecular epidemiologic evidence

FXR-FGF19 signaling in the gut-liver axis is dysregulated in patients with cirrhosis and correlates with impaired intestinal defence

BACKGROUND AND AIMS

Experimental studies linked dysfunctional Farnesoid X receptor (FXR)-fibroblast growth factor 19 (FGF19) signaling to liver disease. This study investigated key intersections of the FXR-FGF19 pathway along the gut-liver axis and their link to disease severity in patients with cirrhosis.

METHODS

Patients with cirrhosis undergoing hepatic venous pressure gradient measurement (cohort-I n = 107, including n = 53 with concomitant liver biopsy; n = 5 healthy controls) or colonoscopy with ileum biopsy (cohort-II n = 37; n = 6 controls) were included. Hepatic and intestinal gene expression reflecting FXR activation and intestinal barrier integrity was assessed. Systemic bile acid (BA) and FGF19 levels were measured.

RESULTS

Systemic BA and FGF19 levels correlated significantly (r = 0.461; p < 0.001) and increased with cirrhosis severity. Hepatic SHP expression decreased in patients with cirrhosis (vs. controls; p < 0.001), indicating reduced FXR activation in the liver. Systemic FGF19 (r = -0.512, p < 0.001) and BA (r = -0.487, p < 0.001) levels correlated negatively with hepatic CYP7A1, but not SHP or CYP8B1 expression, suggesting impaired feedback signaling in the liver. In the ileum, expression of FXR, SHP and FGF19 decreased in patients with cirrhosis, and interestingly, intestinal FGF19 expression was not linked to systemic FGF19 levels. Intestinal zonula occludens-1, occludin, and alpha-5-defensin expression in the ileum correlated with SHP and decreased in patients with decompensated cirrhosis as compared to controls.

CONCLUSIONS

FXR-FGF19 signaling is dysregulated at essential molecular intersections along the gut-liver axis in patients with cirrhosis. Decreased FXR activation in the ileum mucosa was linked to reduced expression of intestinal barrier proteins. These human data call for further mechanistic research on interventions targeting the FXR-FGF19 pathway in patients with cirrhosis.

CLINICAL TRIAL NUMBER

NCT03267615.

Liver cirrhosis and complications from the perspective of dysbiosis

The gut-liver axis refers to the intimate relationship and rigorous interaction between the gut and the liver. The intestinal barrier's integrity is critical for maintaining liver homeostasis. The liver operates as a second firewall in this interaction, limiting the movement of potentially dangerous compounds from the gut and, as a result, contributing in barrier management. An increasing amount of evidence shows that increased intestinal permeability and subsequent bacterial translocation play a role in liver damage development. The major pathogenic causes in cirrhotic individuals include poor intestinal permeability, nutrition, and intestinal flora dysbiosis. Portal hypertension promotes intestinal permeability and bacterial translocation in advanced liver disease, increasing liver damage. Bacterial dysbiosis is closely related to the development of cirrhosis and its related complications. This article describes the potential mechanisms of dysbiosis in liver cirrhosis and related complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma, using dysbiosis of the intestinal flora as an entry point.

Changes of the bacterial composition in duodenal fluid from patients with liver cirrhosis and molecular bacterascites

Small intestinal bacterial overgrowth and compositional changes of intestinal microbiota are pathomechanistic factors in liver cirrhosis leading to bacterial translocation and infectious complications. We analyzed the quantity and composition of duodenal bacterial DNA (bactDNA) in relation to bactDNA in blood and ascites of patients with liver cirrhosis. Duodenal fluid and corresponding blood and ascites samples from 103 patients with liver cirrhosis were collected. Non-liver disease patients (n = 22) served as controls. BactDNA was quantified by 16S-rRNA gene-based PCR. T-RFLP and 16S-rRNA amplicon sequencing were used to analyze bacterial composition. Duodenal bacterial diversity in cirrhosis was distinct to controls showing significantly higher abundances of Streptococcus, Enterococcus and Veillonella. Patients with bactDNA positive ascites revealed reduced spectrum of core microbiota with Streptococcus as key player of duodenal community and higher prevalence of Granulicatella proving presence of cirrhosis related intestinal dysbiosis. Regarding duodenal fluid bactDNA quantification, no significant differences were found between patients with cirrhosis and controls. Additionally, percentage of subjects with detectable bactDNA in blood did not differ between patients and controls. This study evaluated the diversity of bacterial DNA in different body specimens with potential implications on understanding how intestinal bacterial translocation may affect infectious complications in cirrhosis.

Bacterial translocation occurs early in cirrhosis and triggers a selective inflammatory response

BACKGROUND

Experimental data suggest that bacterial translocation (BT) promotes systemic inflammation, portal hypertension, and circulatory dysfunction in advanced chronic liver disease (ACLD).

METHODS

Patients with ACLD undergoing hepatic venous pressure gradient (HVPG) measurement and absence of acute decompensation or infections were included (n = 249). Serum biomarkers of BT (lipopolysaccharide [LPS], lipoteichoic acid [LTA], bacterial DNA [bactDNA]), systemic inflammation and markers of circulatory dysfunction were assessed. T-cell subsets in intestinal biopsies (n = 7 ACLD, n = 4 controls) were analyzed by flow cytometry.

RESULTS

Patients had a median HVPG of 18 (12-21) mmHg and 56% had decompensated ACLD. LPS (0.04 [0.02-0.06] vs. 0.64 [0.30-1.06] EU/mL), LTA (4.53 [3.58-5.97] vs. 43.2 [23.2-109] pg/mL), and detection of bactDNA (≥ 5 pg/mL; 5% vs. 41%) were markedly higher in patients with ACLD than healthy controls (n = 40; p < 0.001) but were similar between different clinical stages of compensated and decompensated ACLD and displayed no meaningful correlation with HVPG and systemic hemodynamics. TNF-α and IL-10 correlated with LPS (Spearman's rs = 0.523, p < 0.001/rs = 0.143, p = 0.024) but not with LTA. Presence of bactDNA was associated with higher LPS (0.54 [0.28-0.95] vs. 0.88 [0.32-1.31] EU/mL, p = 0.001) and TNF-α (15.3 [6.31-28.1] vs. 20.9 [13.8-32.9] pg/mL). Patients with ACLD exhibited a decreased CD4:CD8-ratio and increased TH1-cells in the intestinal mucosa as compared to controls. During a median FU of 14.7 (8.20-26.5) months, bacterial antigens did not predict decompensation or liver-related death (in contrast to HVPG, IL-6, and MAP) as well as infections at 24 months.

CONCLUSION

BT occurs already in early ACLD stages and triggers a systemic inflammatory response via TNF-α and IL-10. Interestingly, BT markers showed no clear correlation with portal hypertension and circulatory dysfunction in patients with stable ACLD.

CLINICAL TRIAL NUMBER

NCT03267615.

Gut microbiota alteration and modulation in hepatitis B virus-related fibrosis and complications: Molecular mechanisms and therapeutic inventions

Hepatitis B virus (HBV) has posed a threat to public health, mainly resulting in liver damage. With long-term accumulation of extracellular matrix, patients with chronic hepatitis B are at high risk of developing into liver fibrosis and cirrhosis and even life-threatening hepatic carcinoma. The occurrence of complications such as spontaneous bacterial peritonitis and hepatic encephalopathy greatly increases disability and mortality. With deeper understanding of the bidirectional interaction between the liver and the gut (gut-liver axis), there is a growing consensus that the human health closely relates to the gut microbiota. Supported by animal and human studies, the gut microbiota alters as the HBV-related liver fibrosis initials and progresses, characterized as the decrease of the ratio between “good” and “potentially pathogenic” microbes. When the primary disease is controlled via antiviral treatment, the gut microbiota dysfunction tends to be improved. Conversely, the recovery of gut microbiota can promote the regression of liver fibrosis. Therapeutic strategies targeted on gut microbiota (rifaximin, probiotics, engineered probiotics and fecal microbiota transplantation) have been applied to animal models and patients, obtaining satisfactory results.

Epidemiology of ascites fluid infections in patients with cirrhosis in Queensland, Australia from 2008 to 2017: A population-based study

Spontaneous bacterial peritonitis (SBP), a common infection in patients with cirrhosis and ascites, is associated with high morbidity and mortality. The aim of this study was to investigate changes in the epidemiology of ascites fluid infections over time in an Australian population, including patient demographics, trends in mortality, length of hospital stay and the nature and antibiotic resistance profile of causative organisms.An observational descriptive population-based epidemiological study of patients with cirrhosis admitted to public hospitals in Queensland during 2008-2017 was performed, linking demographic/clinical and microbiology data.Among 103,165 hospital admissions of patients with cirrhosis, ascites was present in 16,550 and in 60% (9977) a sample of ascitic fluid was tested. SBP was diagnosed in 770 admissions (neutrophil count >250/ml) and bacterascites in 552 (neutrophil count <250/ml with positive culture). The number of admissions with an ascites fluid infection increased by 76% from 2008 to 2017, paralleling an 84% increase in cirrhosis admissions over the same timeframe. Patients with SBP had a longer hospital stay (median 15.7 vs 8.3 days for patients without SBP, P < .001) and higher in-hospital mortality, although this decreased from 39.5% in 2008 to 2010 to 24.8% in 2015 to 2017 (P < .001). Common Gram-positive isolates included coagulase negative staphylococci (37.9%), viridans group streptococci (12.1%), and Staphylococcus aureus (7.2%). Common Gram-negative isolates included Escherichia coli (13.0%), Klebsiella pneumoniae (3.1%) and Enterobacter cloacae (2.6%). The prevalence of resistance to any tested antibiotic was <10%.SBP remains associated with high in-hospital mortality and long hospital stay. Typical skin and bowel pathogens were common, therefore, empirical antibiotic therapy should target these pathogens. This study provides valuable evidence informing infection management strategies in this vulnerable patient population.

The unforeseen intracellular lifestyle of Enterococcus faecalis in hepatocytes

Enterococcus faecalis is a bacterial species present at a subdominant level in the human gut microbiota. This commensal turns into an opportunistic pathogen under specific conditions involving dysbiosis and host immune deficiency. E. faecalis is one of the rare pathobionts identified to date as contributing to liver damage in alcoholic liver disease. We have previously observed that E. faecalis is internalized in hepatocytes. Here, the survival and fate of E. faecalis was examined in hepatocytes, the main epithelial cell type in the liver. Although referred to as an extracellular pathogen, we demonstrate that E. faecalis is able to survive and divide in hepatocytes, and form intracellular clusters in two distinct hepatocyte cell lines, in primary mouse hepatocytes, as well as in vivo. This novel process extends to kidney cells. Unraveling the intracellular lifestyle of E. faecalis, our findings contribute to the understanding of pathobiont-driven diseases.

Review article: therapeutic aspects of bile acid signalling in the gut-liver axis

BACKGROUND

Bile acids are important endocrine modulators of intestinal and hepatic signalling cascades orchestrating critical pathophysiological processes in various liver diseases. Increasing knowledge on bile acid signalling has stimulated the development of synthetic ligands of nuclear bile acid receptors and other bile acid analogues.

AIM

This review summarises important aspects of bile acid-mediated crosstalk between the gut and the liver ("gut-liver axis") as well as recent findings from experimental and clinical studies.

METHODS

We performed a literature review on bile acid signalling, and therapeutic applications in chronic liver disease.

RESULTS

Intestinal and hepatic bile acid signalling pathways maintain bile acid homeostasis. Perturbations of bile acid-mediated gut-liver crosstalk dysregulate transcriptional networks involved in inflammation, fibrosis and endothelial dysfunction. Bile acids induce enterohepatic feedback signalling by the release of intestinal hormones, and regulate enterohepatic circulation. Importantly, bile acid signalling plays a central role in maintaining intestinal barrier integrity and antibacterial defense, which is particularly relevant in cirrhosis, where bacterial translocation has a profound impact on disease progression. The nuclear bile acid farnesoid X receptor (FXR) is a central intersection in bile acid signalling and has emerged as a relevant therapeutic target.

CONCLUSIONS

Experimental evidence suggests that bile acid signalling improves the intestinal barrier and protects against bacterial translocation in cirrhosis. FXR agonists have displayed efficacy for the treatment of cholestatic and metabolic liver disease in randomised controlled clinical trials. However, similar effects remain to be shown in advanced liver disease, particularly in patients with decompensated cirrhosis.

Obeticholic Acid Decreases Intestinal Content of Enterococcus in Rats With Cirrhosis and Ascites

The intestinal microbiome and bacterial translocation (BT), the passage of microorganisms from the gut lumen to mesenteric lymph nodes and other extra-intestinal sites, are main mechanisms implicated in liver injury and further decompensation in patients with cirrhosis. We hypothesized that obeticholic acid (OCA), a semisynthetic bile acid, would change the microbiome composition and reduce bacterial translocation in experimental cirrhosis. Rats with cirrhosis induced by carbon tetrachloride inhalation (a nonseptic model) with ascites present for at least 7 days were randomized to receive a 14-day course of OCA at a dose of 5 mg/kg/day (n = 34) or placebo (n = 34). Stool was collected at days 1 (randomization), 8, and 14 (sacrifice) for analysis of intestinal microbiome using the V4 hypervariable region of the bacterial 16S gene amplified by polymerase chain reaction. Bacteriological cultures of mesenteric lymph nodes, blood, and ascites were performed at end of study. Twenty-four animals in each group reached the end of study. Compared with placebo, rats treated with OCA had decreased relative abundance of Enterococcus in both ileum content (P = 0.02) and in stool (P < 0.001). BT from pathogenic bacteria was not different between groups. At end of treatment, rats on OCA had a significantly lower aspartate aminotransferase (AST) (266 vs. 369 IU/L; P < 0.01) and higher serum albumin (0.9 vs. 0.7 g/dL; P < 0.01) than rats on placebo. Conclusion: Although OCA did not appear to reduce BT by pathogenic bacteria, the reduction in intestinal content of Enterococcus, which has been associated with hepatocyte death, in OCA-treated animals is consistent with our observed improvements in AST and in liver function, as evidenced by higher serum albumin.

Upregulated expression of hypoxia reactive genes in peripheral blood mononuclear cells from chronic liver disease patients

Liver fibrosis induces intrahepatic microcirculation disorder and hypoxic stress. Hypoxic stress has the potential for an increase in the possibility of more liver fibrosis and carcinogenesis. Liver biopsy is a standard method that evaluates of intrahepatic hypoxia, however, is invasive and has a risk of bleeding as a complication. Here, we investigated the hypoxia reactive gene expressions in peripheral blood mononuclear cells (PBMC) from chronic liver disease patients to evaluate intrahepatic hypoxia in a non-invasive manner. The subjects enrolled for this study were composed of 20 healthy volunteers (HV) and 48 patients with chronic liver disease (CLD). CLD patients contained 24 patients with chronic hepatitis（CH）and 24 patients with liver cirrhosis (LC). PBMC were isolated from heparinized peripheral blood samples. We measured the transcriptional expression of hypoxia reactive genes and inflammatory cytokines by quantitative RT-PCR. mRNA expression of adrenomedullin (AM), vascular endothelial growth factor A (VEGFA) superoxide dismutase (SOD), glutathione peroxidase (GPx) (p < 0.05), Interleukin-6 (IL-6), transforming growth factor-beta (TGF-β) and heme oxygenase-1 (HO-1) in CLD group were significantly higher than HV. AM mRNA expression is correlated with serum lactate dehydrogenase (LDH), serum albumin (Alb), IL6, and SOD mRNA expression. The hypoxia reactive gene expression in PBMCs from CLD patients was more upregulated than HV. Especially, angiogenic genes were notably upregulated and correlated with liver fibrosis. Here, we suggest that mRNA expression of AM in PBMCs could be the biomarker of intrahepatic hypoxia.

•

The hypoxia reactive genes in PBMC were elevated in patients with chronic liver disease.

^•Angiogenic genes were upregulated and correlated with liver fibrosis in patients with chronic liver disease.

^•Adrenomedullin mRNA expression in PBMC was correlated with liver function.

^•mRNA expression of adrenomedullin in PBMC could be the biomarker of intrahepatic hypoxia.

Clostridioides difficile Infection and Liver Cirrhosis - A Retrospective, Cohort Study

Purpose

Clostridioides difficile infection (CDI) is one of the most common health care-associated infections in the United States. Studies revealed a higher mortality when CDI is associated with liver cirrhosis. We aim to present the outcomes of CDI among patients with and without liver cirrhosis and to analyze the association of Model for End-Stage Liver Disease (MELD) and Child-Pugh (CPT) scoring with the severity of CDI.

Methods

A retrospective observational study was conducted in hospitalized patients with CDI diagnosed via a 2-step method – glutamate dehydrogenase (GDH) and toxin polymerase chain reaction (PCR). Patients with liver cirrhosis were identified based on ICD codes and chart review. MELD and CPT scores were calculated using laboratory parameters at the time of hospitalization. We compared CDI-related mortality in patients with and without cirrhosis and reviewed the CDI severity distribution in cirrhosis patients.

Results

A total of 526 patients were included in the study, of which 478 (90.87%) were non-cirrhotic and 48 (9.13%) were cirrhotic patients. Mortality rate was higher in cirrhosis group compared to the non-cirrhosis group (39.6% vs. 14.6%,P = 0.001). Among cirrhosis patients, those who survived had lower MELD score compared to the expired group (14.9 vs. 18.58, P = 0.106). There was no correlation of mortality based on CPT score in the cirrhosis group (P = 0.062). In post hoc analysis comparing the severity of CDI to liver cirrhosis, cirrhosis patients are more likely to present with severe-complicated disease. Multivariate logistic regression identified liver cirrhosis, severe-complicated CDI and serum albumin level as independent predictors of mortality.

Conclusion

Our study noted a more severe disease presentation and higher mortality in patients with cirrhosis admitted with CDI. Further studies are required for better understanding of the clinical course of CDI in cirrhosis and to evaluate the need for early intervention in this patient group.

Non-selective beta-blocker use in cirrhotic patients is associated with a reduced likelihood of hospitalisation for infection

BACKGROUND

Non-selective beta-blockers (NSBBs) reduce enteric bacterial translocation rates and the frequency of spontaneous bacterial peritonitis (SBP) in animal models.

AIM

To evaluate the effect of NSBBs on infection-related admissions.

METHODS

We performed a case-control study of cirrhotic patients' first in-patient admission between 1 January 2011 and 31 December 2016. We examined NSBB use and the development of infection. We performed a propensity score-matched analysis in those with NSBB use vs no use and calculated odds ratios on this matched cohort to determine the odds of outcomes based on NSBB use.

RESULTS

We identified 2165 cirrhotic patients who met our inclusion criteria. Most patients were Caucasian (69%), male (62%). Admission Model for End stage Liver Disease (MELD) score, Charlson comorbidity index and Child-Pugh score were 12 ± 1, 4 ± 2, and 8 ± 2, respectively. Ascites was the most common complication of portal hypertension (44%); 23% of patients used NSBBs at home. Infections occurred in 33% of admissions. In the propensity score-matched cohort, the use of NSBBs at home was associated with lower overall, and specific, infections. The effect was similar in patients taking NSBBs for either primary or secondary oesophageal variceal prophylaxis and for those on NSBBs for other indications. Patients not on NSBBs had higher odds of infection (OR = 2.5), SBP (OR = 4.0), and bacteraemia (OR = 6.0).

CONCLUSION

Home use of NSBBs by patients with cirrhosis was associated with fewer infection-related admissions. The data suggest that NSBBs in this group of patients reduce the risk of infection.

Contribution of the Intestinal Microbiome and Gut Barrier to Hepatic Disorders

Intestinal barrier dysfunction and dysbiosis contribute to development of diseases in liver and other organs. Physical, immunologic, and microbiologic (bacterial, fungal, archaeal, viral, and protozoal) features of the intestine separate its nearly 100 trillion microbes from the rest of the human body. Failure of any aspect of this barrier can result in translocation of microbes into the blood and sustained inflammatory response that promote liver injury, fibrosis, cirrhosis, and oncogenic transformation. Alterations in intestinal microbial populations or their functions can also affect health. We review the mechanisms that regulate intestinal permeability and how changes in the intestinal microbiome contribute to development of acute and chronic liver diseases. We discuss individual components of the intestinal barrier and how these are disrupted during development of different liver diseases. Learning more about these processes will increase our understanding of the interactions among the liver, intestine, and its flora.

Liver Cirrhosis and Sarcopenia from the Viewpoint of Dysbiosis

Sarcopenia in patients with liver cirrhosis (LC) has been attracting much attention these days because of the close linkage to adverse outcomes. LC can be related to secondary sarcopenia due to protein metabolic disorders and energy metabolic disorders. LC is associated with profound alterations in gut microbiota and injuries at the different levels of defensive mechanisms of the intestinal barrier. Dysbiosis refers to a state in which the diversity of gut microbiota is decreased by decreasing the bacterial species and the number of bacteria that compose the gut microbiota. The severe disturbance of intestinal barrier in LC can result in dysbiosis, several bacterial infections, LC-related complications, and sarcopenia. Here in this review, we will summarize the current knowledge of the relationship between sarcopenia and dysbiosis in patients with LC.

Review article: emerging role of the gut microbiome in the progression of nonalcoholic fatty liver disease and potential therapeutic implications

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a prevalent disorder associated with obesity and diabetes. Few treatment options are effective for patients with NAFLD, but connections between the gut microbiome and NAFLD and NAFLD-associated conditions suggest that modulation of the gut microbiota could be a novel therapeutic option.

AIM

To examine the effect of the gut microbiota on pathophysiologic causes of NAFLD and assess the potential of microbiota-targeting therapies for NAFLD.

METHODS

A PubMed search of the literature was performed; relevant articles were included.

RESULTS

The composition of bacteria in the gastrointestinal tract can enhance fat deposition, modulate energy metabolism and alter inflammatory processes. Emerging evidence suggests a role for the gut microbiome in obesity and metabolic syndrome. NAFLD is often considered the hepatic manifestation of metabolic syndrome, and there has been tremendous progress in understanding the association of gut microbiome composition with NAFLD disease severity. We discuss the role of the gut microbiome in NAFLD pathophysiology and whether the microbiome composition can differentiate the two categories of NAFLD: nonalcoholic fatty liver (NAFL, the non-progressive form) vs nonalcoholic steatohepatitis (NASH, the progressive form). The association between gut microbiome and fibrosis progression in NAFLD is also discussed. Finally, we review whether modulation of the gut microbiome plays a role in improving treatment outcomes for patients with NAFLD.

CONCLUSIONS

Multiple pathophysiologic pathways connect the gut microbiome with the pathophysiology of NAFLD. Therefore, therapeutics that effectively target the gut microbiome may be beneficial for the treatment of patients with NAFLD.

Prevalence and predictors for spontaneous bacterial peritonitis in cirrhotic patients with ascites admitted at medical block in Korle-Bu Teaching Hospital, Ghana

Introduction

Spontaneous bacterial peritonitis (SBP) is one of the most common and life-threatening complications of patients with cirrhotic ascites. Recognition and prompt treatment of this condition is essential to prevent serious morbidity and mortality. This study aimed to determine the prevalence of SBP among in-patients with cirrhotic ascites attending our facility and to determine the clinical and laboratory parameters associated with SBP.

Methods

A cross-sectional study was conducted involving one hundred and three (103) patients admitted at medical block in the Korle-Bu Teaching Hospital (KBTH) with cirrhotic ascites from 25^th March, 2016 to 25^th November, 2016. Demographic and clinical data were collected using a standardized questionnaire. Ascitic fluid culture and cell count were conducted. Positive ascitic fluid culture and/or ascitic polymorphonuclear leukocyte ≥ 250cells/mm³ were diagnostic for SBP.

Results

Of the 103 patients with cirrhotic ascites, the mean age was 43.5 ± 12.2 years. There were fifty eight (58) male patients. The prevalence of SBP was 25.24% (26/103). Majority, 5 (55.6%) of the bacteria isolated from ascitic fluid with SBP was Escherichia coli. Severe ascites and high INR were found to be independent predictors of SBP.

Conclusion

SBP is common among patients with cirrhotic ascites admitted at KBTH. Severe ascites and high INR were highly suggestive of SBP. Diagnostic paracentesis should be done immediately on admission to confirm the diagnosis irrespective of the clinical characteristics as part of baseline investigation.

Small Intestinal Bacterial Overgrowth in Patients With Cirrhosis

Small intestinal bacterial overgrowth (SIBO) is defined by increased density and/or abnormal composition of microbiota in the small bowel. SIBO is often encountered in patients with cirrhosis as a result of impaired intestinal motility and delayed transit time, both of which are exacerbated by more severe liver disease. Additional risk factors for SIBO commonly encountered in cirrhotic patients include coexisting diabetes, autonomic neuropathy, and/or alcoholic use. Diagnosis of SIBO is performed by breath testing or jejunal aspiration, the gold standard. In cirrhotic patients, the presence of SIBO can lead to profound clinical consequences. Increased intestinal permeability in these patients predisposes to bacterial translocation into the systemic circulation. As a result, SIBO is implicated as a significant risk factor in the pathogenesis of both spontaneous bacterial peritonitis and hepatic encephalopathy in cirrhotics. Antibiotics, especially rifaximin, are the best studied and most effective treatment options for SIBO. However, prokinetics, probiotics, nonselective beta-blockers, and treatment of underlying liver-related pathophysiology with transjugular intrahepatic portosystemic shunt placement or liver transplantation are also being investigated. This review will discuss the risk factors, diagnosis, manifestations in cirrhosis, and treatment options of SIBO.

Single versus double experimental bile duct ligation model for inducing bacterial translocation

BACKGROUND

Double common bile duct ligation plus section in rats is used as a model for bacterial translocation, a phenomenon that has been correlated with the degree of liver damage. This study analyzes whether a simpler variant of the technique is also a valid model to study bacterial translocation.

METHODS

Fifty-six male Sprague Dawley rats underwent one of three surgical interventions: a) proximal double ligation and section of the common bile duct; b) proximal simple ligation of the bile duct; and c) sham operation. Bacterial translocation was measured by cultures of mesenteric lymph nodes, blood, spleen and liver. Stool culture and histological analysis of liver damage were also performed.

RESULTS

The incidence of bacterial translocation in SBL and DBDL groups was 23,5% and 25% respectively. Mortality was similar between ligation groups (11.2% versus 10%). Liver cirrhosis developed in the group of double ligation and section (100% of the animals at 4 weeks), while portal hypertension appeared starting at week 3. None of the animals submitted to simple ligation developed liver cirrhosis.

CONCLUSIONS

Simple bile duct ligation is associated with a similar incidence of bacterial translocation as double ligation, but without cirrhosis or portal hypertension.

Increased serum C-reactive protein and decreased urinary aquaporin 2 levels are predictive of the efficacy of tolvaptan in patients with liver cirrhosis

AIM

Water retention, hepatic ascites, and peripheral edema are significant problems in patients with liver cirrhosis (LC). Although furosemide and spironolactone are commonly used as treatment, they are often insufficient to treat hyponatremia and renal insufficiency in patients with LC. Tolvaptan (TVP) could provide an effective treatment alternative. However, predictive factors of a therapeutic response to TVP are unclear. Our aim was to examine clinical predictors of the response to TVP in patients with LC and water retention.

METHODS

Fifty-two patients were treated with TVP, with therapeutic effects judged by a decrease in body weight (≥2 kg) and increase in urinary volume (≥500 mL) within 7 days. Blood biochemical tests were carried out at baseline and post-treatment, including serum soluble CD14 (sCD14) and urinary aquaporin 2 (AQP2) levels. Clinical and laboratory predictive factors of a TVP response were evaluated by univariate and multivariate analyses.

RESULTS

The overall response to TVP was 55.8%. On univariate analyses, serum C-reactive protein (CRP) level, the neutrophil-to-lymphocyte ratio, urinary blood urea nitrogen, and urinary AQP2 were predictors of the TVP response, with only serum CRP retained on multivariate analysis. A higher serum sCD14 level was strongly associated with a non-response to TVP. A decrease in urinary AQP2 to undetectable level was associated with a response.

CONCLUSION

Tolvaptan provides a rapid and strong effect to improve water retention in patients with LC. Baseline serum sCD14 and CRP levels are useful predictors of a response to TVP, with a decrease in urinary AQP2 during treatment indicating an early response.

[Liver diseases: The pathogenetic role of the gut microbiome and the potential of treatment for its modulation]

The paper gives an update on the role of the gut microbiome (GM) in the development of nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver cirrhosis (LC), and its complications, such as hepatic encephalopathy (HE) and hepatocellular carcinoma (HCC), and discusses the possibilities of its correction with prebiotics, probiotics, synbiotics, antibiotics, and fecal microbiota transplantation (FMT). The pathophysiology of the liver diseases in question demonstrates some common features that are characterized by pathogenic changes in the composition of the gastrointestinal tract microflora, by intestinal barrier impairments, by development of endotoxemia, by increased liver expression of proinflammatory factors, and by development of liver inflammation. In progressive liver disease, the above changes are more pronounced, which contributes to the development of LC, HE, and HCC. GM modulation using prebiotics, probiotics, synbiotics, antibiotics, and FMT diminishes dysbacteriosis, strengthens the intestinal mucosal barrier, reduces endotoxemia and liver damage, and positively affects the clinical manifestations of HE. Further investigations are needed, especially in humans, firstly, to assess a relationship of GM to the development of liver diseases in more detail and, secondly, to obtain evidence indicating the therapeutic efficacy of GM-modulating agents in large-scale, well-designed, randomized, controlled, multicenter studies.

Efficacy of vasopressin V2 receptor antagonist tolvaptan in treatment of hepatic edema

AIM

Tolvaptan, an oral active vasopressin V2 receptor antagonist, is widely used for hepatic edema in Japan, but its clinical benefits have yet to be fully clarified. The present study evaluated the efficacy of tolvaptan in hepatic edema.

METHODS

The efficacy and treatment regimen of tolvaptan were evaluated in 150 patients with hepatic edema by analyzing the initial (day 14) and long-term (day 90) responses to the drug and their predictive factors. All patients were divided into good (Child-Pugh classification B, and absent of advanced hepatocellular carcinoma) and poor hepatic condition groups, and the response rates were compared between the two groups.

RESULTS

The initial response rate was 62%, and the long-term response rate was 47%. The assessment of predictive factors for response to tolvaptan showed that serum creatinine and C-reactive protein levels were important predictors of initial response, and that hepatic conditions, such as the Child-Pugh score or presence of hepatocellular carcinoma, as well as initial response, were significant predictors of long-term response. In addition, both the initial and long-term response rates and the cumulative survival rate were found to be higher in the good hepatic condition group than in the poor hepatic condition group, respectively (71% vs. 57%, P = 0.113; 62% vs. 39%, P = 0.009; log-rank test, P < 0.001).

CONCLUSION

These results suggest that tolvaptan may provide high response rates when used early in the course of hepatic edema, or when both hepatic and renal functions are still retained, leading to an improved disease prognosis.

The Intestinal Microbiome and the Liver Transplant Recipient: What We Know and What We Need to Know

The intestinal microbiome and immune system are in close symbiotic relationship in health. Gut microbiota plays a role in many chronic liver diseases and cirrhosis. However, alterations in the gut microbiome after liver transplantation and the implications for liver transplant recipients are not well understood and rely mainly on experimental animal studies. Recent advances in molecular techniques have identified that increased intestinal permeability, decreased beneficial bacteria, and increased pathogenic species may play important roles in the early posttransplant period. The associations between microbiota perturbation and postliver transplant infections and acute rejection are evolving. The link with metabolic syndrome, obesity, and cardiac disease in the general population require translation into the transplant recipient. This review focuses on our current knowledge of the known and potential interaction of the microbiome in the liver transplant recipient. Future human studies focused on microbiota changes in liver transplant patients are warranted and expected.

Novel prevention strategies for bacterial infections in cirrhosis

INTRODUCTION

Bacterial infections are a serious complication of cirrhosis, as they can lead to decompensation, multiple organ failure, and/or death. Preventing infections is therefore very relevant. Because gut bacterial translocation is their main pathogenic mechanism, prevention of infections is mostly based on the use of orally administered poorly absorbed antibiotics such as norfloxacin (selective intestinal decontamination). However, antibiotic prophylaxis leads to antibiotic resistance, limiting therapy and increasing morbidity and mortality. Prevention of bacterial infections in cirrhosis should therefore move away from antibiotics.

AREAS COVERED

This review focuses on various potentially novel methods to prevent infections in cirrhosis focusing on non-antibiotic strategies. The use of probiotics, nonselective intestinal decontamination with rifaximin, prokinetics and beta-blockers or fecal microbiota transplant as means of targeting altered gut microbiota, bile acids and FXR agonists are all potential alternatives to selective intestinal decontamination. Prokinetics and beta-blockers can improve intestinal motility, while bile acids and FXR agonists help by improving the intestinal barrier. Finally, granulocyte colony stimulating factor (G-CSF) and statins are emerging therapeutic strategies that may improve immune dysfunction in cirrhosis.

EXPERT OPINION

Evidence for these strategies has been restricted to animal studies and proof-of concept studies but we expect this to change in coming years.

Oral administration of Saccharomyces boulardii ameliorates carbon tetrachloride-induced liver fibrosis in rats via reducing intestinal permeability and modulating gut microbial composition

To investigate the effects of orally administrated Saccharomyces boulardii (S. boulardii) on the progress of carbon tetrachloride (CCl4)-induced liver fibrosis, 34 male Wistar rats were randomly divided into four experimental groups including the control group (n = 8), the cirrhotic group (n = 10), the preventive group (n = 8), and the treatment group (n = 8). Results showed that the liver expression levels of collagen, type I, alpha 1 (Col1A1), alpha smooth muscle actin (αSMA), transforming growth factor beta (TGF-β) and the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA) increased significantly in cirrhotic rats compared with control and decreased by S. boulardii administration. Treatment of S. boulardii also attenuated the increased endotoxin levels and pro-inflammatory cytokines in CCl4-treated rats. And, these were associated with the changes of intestinal permeability and fecal microbial composition. Our study suggested that oral administration of S. boulardii can promote the liver function of CCl4-treated rats, and the preventive treatment of this probiotic yeast may decelerate the progress of liver fibrosis.

Effect of long-term acid gastric inhibition on bacterial translocation in cirrhotic rats

BACKGROUND

Bacterial translocation (BT) related to intestinal bacterial overgrowth (IBO) plays an important role in the pathogenesis of bacterial infections in cirrhosis. Inhibition of acid gastric secretion promotes IBO and might favor BT. We evaluated the effect of long-term inhibition of acid gastric secretion on BT in cirrhotic rats.

METHODS

Cirrhotic rats with and without ascites induced by oral CCl4 and controls were randomized to treatment with a daily subcutaneous injection of placebo, ranitidine (50 mg/kg), or pantoprazole (8 mg/kg) during 2 weeks. Continuous pH-metry was performed for 2 h before and at the end of treatment; thereafter, a laparotomy to obtain samples of blood, mesenteric lymph nodes, ascites, spleen, liver, and cecal stools was performed.

RESULTS

Ranitidine and pantoprazole increased gastric pH as compared with placebo (P<0.001). However, antisecretory drugs increased the incidence of BT only in ascitic rats treated with ranitidine (P<0.05) or pantoprazole (P=0.07) when compared with placebo-treated ascitic rats or cirrhotic rats without ascites treated with the same drug. Cirrhotic ascitic rats treated with pantoprazole showed a trend toward an increased incidence of IBO (P=0.08), a higher ileal malondialdehyde level (P<0.01), and an increased production of tumor necrosis factor-α (P<0.05).

CONCLUSION

Although inhibition of acid gastric secretion increased gastric pH in all animals, the incidence of BT increased only in ascitic rats, and it was associated with a trend toward an increase in IBO incidence, a higher ileal malondialdehyde level, and an increased production of serum tumor necrosis factor-α. Therefore, antisecretory drugs should be carefully administered to cirrhotic ascitic patients.

Impacts of gut bacteria on human health and diseases

Gut bacteria are an important component of the microbiota ecosystem in the human gut, which is colonized by 10¹⁴ microbes, ten times more than the human cells. Gut bacteria play an important role in human health, such as supplying essential nutrients, synthesizing vitamin K, aiding in the digestion of cellulose, and promoting angiogenesis and enteric nerve function. However, they can also be potentially harmful due to the change of their composition when the gut ecosystem undergoes abnormal changes in the light of the use of antibiotics, illness, stress, aging, bad dietary habits, and lifestyle. Dysbiosis of the gut bacteria communities can cause many chronic diseases, such as inflammatory bowel disease, obesity, cancer, and autism. This review summarizes and discusses the roles and potential mechanisms of gut bacteria in human health and diseases.

Spontaneous bacterial peritonitis: The clinical challenge of a leaky gut and a cirrhotic liver

Spontaneous bacterial peritonitis (SBP) is a frequent, life-threatening bacterial infection in patients with liver cirrhosis and ascites. Portal hypertension leads to increased bacterial translocation from the intestine. Failure to eliminate invading pathogens due to immune defects associated with advanced liver disease on the background of genetic predisposition may result in SBP. The efficacy of antibiotic treatment and prophylaxis has declined due to the spread of multi-resistant bacteria. Patients with nosocomial SBP and with prior antibiotic treatment are at a particularly high risk for infection with resistant bacteria. Therefore, it is important to adapt empirical treatment to these risk factors and to the local resistance profile. Rifaximin, an oral, non-absorbable antibiotic, has been proposed to prevent SBP, but may be useful only in a subset of patients. Since novel antibiotic classes are lacking, we have to develop prophylactic strategies which do not induce bacterial resistance. Farnesoid X receptor agonists may be a candidate, but so far, clinical studies are not available. New diagnostic tests which can be carried out quickly at the patient’s site and provide additional prognostic information would be helpful. Furthermore, we need tools to predict antibiotic resistance in order to tailor first-line antibiotic treatment of spontaneous bacterial peritonitis to the individual patient and to reduce mortality.

Significant Association between Serum Levels of Von Willebrand Factor (vWF) Antigen with Stages of Cirrhosis

OBJECTIVE

Von Willebrand factor (vWF) is a mediator that increases endotoxemic medium like in cirrhosis. In this study we evaluated the association of serum VWF antigen (Ag) level with the stage of cirrhosis (according to Child-Pugh classification).

MATERIALS AND METHODS

We included 82 cirrhotic patients (Female/Male (F/M): 26/56) and 86 healthy subjects (F/M: 44/42) in the study. Ages of the both groups of patients were not different (P= 0.095). We excluded possible other reasons that may cause VWF level increase. Diagnosis of cirrhosis was made on the basis of biopsy in 7 patients and with clinical and laboratory parameters in 75 patients. VWF Ag level was determined by immunoturbidimetric test. The stage of cirrhosis was defined with Child-Pugh classification. Data were analysed by using Statistical Package for the Social Sciences (SPSS) 10.0 software program.

RESULTS

VWF Ag level was significantly higher in cirrhotic patients compared to control group (220±90 and 87±38, P<0.001, respectively). We observed significant increase of VWF Ag level with the increasing stages of cirrhosis according to Child-Pugh score (VWF Ag level for Child A-B-C 156.4±54/215±45/284.8±93, respectively; P values for Child A-B/A-C/B-C; <0.001/<0.001/0.006, respectively).

CONCLUSION

Serum VWF Ag level increases in cirrhotic patients and this is more pronounced with higher stages of cirrhosis.

Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation

The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review.

Microbiota and the gut-liver axis: Bacterial translocation, inflammation and infection in cirrhosis

Liver disease is associated with qualitative and quantitative changes in the intestinal microbiota. In cirrhotic patients the alteration in gut microbiota is characterized by an overgrowth of potentially pathogenic bacteria (i.e., gram negative species) and a decrease in autochthonous familiae. Here we summarize the available literature on the risk of gut dysbiosis in liver cirrhosis and its clinical consequences. We therefore described the features of the complex interaction between gut microbiota and cirrhotic host, the so called “gut-liver axis”, with a particular attention to the acquired risk of bacterial translocation, systemic inflammation and the relationship with systemic infections in the cirrhotic patient. Such knowledge might help to develop novel and innovative strategies for the prevention and therapy of gut dysbiosis and its complication in liver cirrhosis.

Is there a role for probiotics in liver disease?

Intestinal microbiota plays an important role in health and disease. Alteration in its healthy homeostasis may result in the development of numerous liver disorders including complications of liver cirrhosis. On the other hand, restoration and modulation of intestinal flora through the use of probiotics is potentially an emerging therapeutic strategy. There is mounting evidence that probiotics are effective in the treatment of covert and overt hepatic encephalopathy, as well as in the prevention of recurrence of encephalopathy. The beneficial effect of probiotics also extends to liver function in cirrhosis, nonalcoholic fatty liver disease, and alcoholic liver disease. On the other hand, data associating probiotics and portal hypertension is scanty and conflicting. Probiotic therapy has also not been shown to prevent primary or secondary spontaneous bacterial peritonitis. Larger clinical studies are required before probiotics can be recommended as a treatment modality in liver diseases.

Gut-liver axis improves with meloxicam treatment after cirrhotic liver resection

AIM: To investigate the effect of meloxicam on the gut-liver axis after cirrhotic liver resection.

METHODS: Forty-four male Wistar rats were assigned to three groups: (1) control group (CG); (2) bile duct ligation with meloxicam treatment (BDL + M); and (3) bile duct ligation without meloxicam treatment (BDL). Secondary biliary liver cirrhosis was induced via ligature of the bile duct in the BDL + M and BDL groups. After 2 wk, the animals underwent a 50% hepatectomy. In the BDL + M group 15 min prior to the hepatectomy, one single dose of meloxicam was administered. Parameters measured included: microcirculation of the liver and small bowel; portal venous flow (PVF); gastrointestinal (GI) transit; alanine aminotransferase (ALT); malondialdehyde; interleukin 6 (IL-6), transforming growth factor beta 1 (TGF-β1) and hypoxia-inducible factor 1 alpha (HIF-1α) levels; mRNA expression of cyclooxigenase-2 (COX-2), IL-6 and TGF-β1; liver and small bowel histology; immunohistochemical evaluation of hepatocyte and enterocyte proliferation with Ki-67 and COX-2 liver expression.

RESULTS: Proliferative activity of hepatocytes after liver resection, liver flow and PVF were significantly higher in CG vs BDL + M and CG vs BDL group (P < 0.05), whereas one single dose of meloxicam ameliorated liver flow and proliferative activity of hepatocytes in BDL + M vs BDL group. COX-2 liver expression at 24 h observation time (OT), IL-6 concentration and mRNA IL-6 expression in the liver especially at 3 h OT, were significantly higher in BDL group when compared with the BDL + M and CG groups (P < 0.01, P < 0.001, P < 0.01, respectively). Liver and small bowel histology, according to a semi quantitative scoring system, showed better integrity in BDL + M and CG as compared to BDL group. ALT release and HIF-1α levels at 1 h OT were significantly higher in BDL + M compared to CG and BDL group (P < 0.001 and P < 0.01, respectively). Moreover, ALT release levels at 3 and 24 h OT were significantly higher in BDL group compared to CG, P < 0.01. GI transit, enterocyte proliferative activity and number of goblet cells were in favor of meloxicam treatment vs BDL group (P < 0.05, P < 0.001, P < 0.01, respectively). Additionally, villus length were higher in BDL + M as compared to BDL group.

CONCLUSION: One single dose of meloxicam administered after cirrhotic liver resection was able to cause better function and integrity of the remaining liver and small bowel.

Gut microbiota and liver disease

Microbes are present in large numbers in each human being, in particularly in the gastrointestinal (GI) tract, and have long been believed to have some beneficial effects for their hosts. Till recently, however, we lacked tools for studying these organisms. Rapid technological advances in recent years have markedly improved our understanding of their role both in health and disease. Recent literature suggests that organisms in the GI tract, referred to collectively as gut microbiota, play an indispensable role in the maintenance of host's homeostasis. Alterations in the gut microbiota, that is in the nature and relative density of various constituent bacterial species, appear to have a role in pathogenesis and progression of several GI and hepatic diseases. This has also opened the vista for tinkering with gut flora in an attempt to treat or prevent such diseases. In this review, we have tried to summarize information on normal gut microbiota, laboratory techniques and animal models used to study it, and the role of its perturbations in some of the common hepatic disorders, such as non-alcoholic fatty liver disease (including obesity), non-alcoholic steatohepatitis, alcoholic liver disease, and liver cirrhosis and its complications.

Recent insights into the pathogenesis of hepatic encephalopathy and treatments

Hepatic encephalopathy (HE) encompasses a spectrum of neuropsychiatric disorders related to liver failure. The development of HE can have a profound impact on mortality as well as quality of life for patients and carers. Ammonia is central in the disease process contributing to alteration in neurotransmission, oxidative stress, and cerebral edema and astrocyte swelling in acute liver failure. Inflammation in the presence of ammonia coactively worsens HE. Inflammation can result from hyperammonemic responses, endotoxemia, innate immune dysfunction or concurrent infection. This review summarizes the current processes implicated in the pathogenesis of HE, as well as current and potential treatments. Treatments currently focus on reducing inflammation and/or blood ammonia levels and provide varying degrees of success. Optimization of current treatments and initial testing of novel therapies will provide the basis of improvement of care in the near future.

VSL#3 ® probiotic therapy does not reduce portal pressures in patients with decompensated cirrhosis

BACKGROUND & AIMS

In patients with decompensated cirrhosis, bacterial translocation can contribute to splanchnic vasodilatation, decreased effective circulating volume, and portal hypertension. The primary objective of this randomized, double blind placebo controlled trial was to evaluate the effect of the probiotic VSL#3(®) on the hepatic venous pressure gradient (HVPG).

METHODS

Seventeen patients with decompensated cirrhosis and an HVPG of ≥ 10 mmHg were randomized to receive 2 months of VSL#3(®) or an identical placebo. HVPG, endotoxin, interleukin (IL)-6, IL-8, IL-10, renin, aldosterone, nitric oxide and stool microbiota were measured at baseline and study end.

RESULTS

Two of the 17 patients were taken off the trial before completion (one for alcohol abuse and the second for SBP - both in placebo arm). Data were analysed on the remaining 15 patients. The median model for end-stage liver disease score was 12, and 80% of patients had Child Pugh B disease. The treatment arm had a greater decrease in HVPG from baseline to study end than the placebo arm (median change from baseline -11.6% vs +2.8%), although this reduction was not statistically significant in either group. There was a significant reduction in the plasma aldosterone level in the VSL#3(®) group, but no significant changes in the other measured parameters, including the stool microflora analysis.

CONCLUSIONS

Within the limitations of our sample size, VSL#3(®) therapy does not appear to have a significant impact on portal pressure reduction in patients with decompensated cirrhosis.

Role of proton pump inhibitors in the occurrence and the prognosis of spontaneous bacterial peritonitis in cirrhotic patients with ascites

BACKGROUND

Proton pump inhibitors (PPIs) facilitate intestinal bacterial translocation. No robust data exist demonstrating that PPIs increase the risk of spontaneous bacterial peritonitis (SBP) and that PPIs worsen the prognosis of SBP patients. PPI use might be unsuitable for cirrhotic patients.

AIMS

To analyse: (i) the role of PPIs in the occurrence of SBP in cirrhotic patients; (ii) their impact on the prognosis of SBP patients; and (iii) the suitability of their use.

METHODS

In this retrospective case-control study, PPI use was first assessed in cirrhotic patients consecutively admitted with SBP (group I) and in a control group that included the same number of uninfected cirrhotic patients with ascites (group II). Afterwards, the impact of PPIs on SBP was assessed in group I by comparing survival of patients with and without PPIs.

RESULTS

A total of 102 patients were included, 51 in each group. (i) SBP patients were more frequently treated by PPIs than controls (49 vs. 25%, P = 0.014). (ii) In group I, patients with (n = 25) and without (n = 26) PPIs had similar survival rates at 1 month (64.0 ± 9.6% vs. 59.4 ± 10.0%), 3 months (41.2 ± 10.2% vs. 44.6 ± 10.6%), and 1 year (26.6 ± 9.6% vs. 28.9 ± 10.1%), and similar median age at death (53 vs. 57 years). (iii) The reason for PPI use was inappropriate or undocumented in 34% of group I and II.

CONCLUSIONS

Proton pump inhibitors were more frequently used in SBP patients than in controls, but did not influence the prognosis in SBP. Overuse of PPIs was encountered in one-third of cirrhotic patients and should be avoided.

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-γ mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis.

Pathological bacterial translocation in cirrhosis: pathophysiology, diagnosis and clinical implications

Bacterial translocation (BT) is defined by the passage of viable indigenous bacteria from the intestinal lumen to mesenteric lymph nodes (MLNs) and other territories, and its diagnostic criteria rely on the isolation of viable bacteria in MLNs. Small intestinal overgrowth, increased intestinal permeability and immunological alterations are the main factors involved in its pathogenesis. BT is obviously difficult to identify in patients with cirrhosis, and alternative methods have been proposed instead. Bacterial DNA detection and species identification in serum or ascitic fluid has been proposed as a reliable marker of BT. Bacterial products, such as endotoxin, or bacterial DNA can translocate to extra-intestinal sites and promote an immunological response similar to that produced by viable bacteria. Therefore, pathological BT plays an important role in the pathogenesis of the complications of cirrhosis, not only in infections, but by exerting a profound inflammatory state and exacerbating the haemodynamic derangement. This may promote in turn the development of hepatorenal syndrome, hepatic encephalopathy and other portal hypertension-related complications. Therapeutic approaches for the prevention of BT in experimental and human cirrhosis are summarized. Finally, new investigations are needed to better understand the pathogenesis and consequences of translocation by viable bacteria (able to grow in culture), or non-viable BT (detection of bacterial fragments with negative culture) and open new therapeutic avenues in patients with cirrhosis.

Cirrhosis, cellulitis and cats: a 'purrfect' combination for life-threatening spontaneous bacterial peritonitis from Pasteurella multocida

Pasteurella multocida is a Gram-negative coccobacillus that colonises the upper airways of many animals, in particular, dogs and cats. It acts as an opportunistic infection in humans following an animal bite or scratch and is associated with soft tissue infections, septicaemia and pneumonia, particularly in patients with a compromised immune response, such as patients with liver failure. Spontaneous bacterial peritonitis (SBP) is a serious complication of cirrhosis with a death rate of 10-15%. We report a case of a 47-year-old man with cirrhosis who presented with life-threatening P multocida SBP and bacteraemia secondary to a lick from a cat to a cellulitic leg wound. This case highlights the potential severity of an infection from domestic animals and an otherwise innocuous organism in an immunocompromised host.

The role of rifaximin in the primary prophylaxis of spontaneous bacterial peritonitis in patients with liver cirrhosis

BACKGROUND

Primary prophylaxis of spontaneous bacterial peritonitis (SBP) may provide a survival advantage in cirrhotic patients with ascites and has become an integral part of clinical practice. Rifaximin is a poorly absorbable antibiotic with a broad spectrum of antibacterial action and has low risk of introducing bacterial resistance.

AIM

To determine whether rifaximin is associated with decreasing the risk of SBP and improving transplant-free survival in cirrhotic patients with ascites.

METHODS

The medical records of all adult patients with liver cirrhosis and large ascites justifying paracentesis evaluated in our clinic (2003 to 2007) were reviewed. Patients were stratified into 2 groups by the use of rifaximin. Patients were excluded if they had received another antibiotic for SBP prophylaxis or had a history of SBP before rifaximin therapy.

RESULTS

A total of 404 patients were included, of whom 49 (12%) received rifaximin. The rifaximin and nonrifaximin groups were comparable with regards to age, sex, and race. The median follow-up time was 4.2 [1.0, 17.1] months. During this time period, 89% of patients on rifaximin remained SBP free compared with 68% of those not on rifaximin (P=0.002). After adjusting for Model of End-Stage Liver Disease score, Child-Pugh score, serum sodium, and ascitic fluid total protein, there was a 72% reduction in the rate of SBP in the rifaximin group (hazard ratio=0.28; 95% confidence interval, 0.11-0.71; P=0.007). The group treated with rifaximin also demonstrated a transplant-free survival benefit compared with those not on rifaximin (72% vs. 57%, P=0.045).

CONCLUSIONS

Intestinal decontamination with rifaximin may prevent SBP in cirrhotic patients with ascites. Prospective randomized controlled trials are needed to confirm this finding.

Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Effects of pentoxifylline on intestinal bacterial overgrowth, bacterial translocation and spontaneous bacterial peritonitis in cirrhotic rats with ascites

BACKGROUND

Prophylaxis of spontaneous bacterial peritonitis with norfloxacin has been associated to development of antibiotic resistance. We investigated whether pentoxifylline compared to norfloxacin reduces bacterial translocation and spontaneous bacterial peritonitis in rats with CCl(4)-induced cirrhosis and ascites.

METHOD

After development of cirrhosis and ascites, animals were randomly allocated to receive pentoxifylline (16 mg/kg/d every 8h, oral route, n=13) or placebo (n=12) for 15 days. An additional group of 8 cirrhotic rats was given norfloxacin (5mg/kg/d for 15 days). Six healthy rats served as controls. Cecal flora and the prevalence of bacterial translocation and spontaneous bacterial peritonitis were analysed. Serum and ascitic fluid levels of TNF-alpha and cecal levels of malondialdehyde were also measured.

RESULTS

Pentoxifylline in comparison to placebo reduced intestinal bacterial overgrowth (21% vs. 67%, p=0.04), bacterial translocation to cecal lymph nodes (23% vs. 75%, p=0.03) and prevented spontaneous bacterial peritonitis (0% vs. 33%, p=0.04) by Enterobacteriaceae. Norfloxacin administration induced similar results. Pentoxifylline (0.18 ± 0.10 nmol/mg), but not norfloxacin (0.25 ± 0.13; p=0.02), significantly reduced cecal mucosal levels of malondialdehyde compared to placebo (0.33 ± 0.16; p=0.03).

CONCLUSION

In cirrhotic rats with ascites: (a) pentoxifylline as well as norfloxacin reduced intestinal bacterial overgrowth and bacterial translocation and prevented spontaneous bacterial peritonitis; (b) pentoxifylline, but not norfloxacin, reduced oxidative stress in cecal mucosal.

Spontaneous bacterial peritonitis in patients with hepatitis B virus-related liver cirrhosis: community-acquired versus nosocomial

PURPOSE

Spontaneous bacterial peritonitis (SBP) frequently develops in patients with liver cirrhosis; however, there is little data to suggest whether the acquisition site of infection influences the prognosis. This study compared the bacteriology, clinical characteristics and treatment outcomes of community-acquired SBP (CA-SBP) and nosocomial SBP (N-SBP).

MATERIALS AND METHODS

The medical records of 130 patients with hepatitis B virus (HBV)-related liver cirrhosis, who had experienced a first episode of SBP between January 1999 and December 2008, were reviewed.

RESULTS

The study population included 111 (85.4%) patients with CA-SBP and 19 (14.6%) patients with N-SBP. Baseline and microbiological characteristics as well as clinical course, including in-hospital mortality, did not differ between patients with CA-SBP and those with N-SBP (all p>0.05). The median survival time was 6.5 months, and 117 (90.0%) patients died during the follow-up period. Patients with CA-SBP and N-SBP survived for median periods of 6.6 and 6.2 months, respectively, without significant difference (p=0.569). Time to recurrence did not differ between patients with CA-SBP and N-SBP (4.7 vs. 3.6 months, p=0.925).

CONCLUSION

The acquisition site of infection did not affect clinical outcomes for patients with HBV-related liver cirrhosis who had experienced their first episode of SBP. Third-generation cephalosporins may be effective in empirically treating these patients, regardless of the acquisition site of the infection.

Predictive Value of the Model of End-Stage Liver Disease in Cirrhotic Patients with and without Spontaneous Bacterial Peritonitis

Objective. We aimed to assess the predictive value of the model of end-stage liver disease (MELD) in hospitalized cirrhotic patients with and without spontaneous bacterial peritonitis (SBP) and fatal outcome. Methods. A cross-sectional study included 256 consecutive patients (199 men and 57 women) diagnosed with cirrhosis and ascites who were hospitalized at the University Hospital Center in Tirana from January 2008 to December 2009. SBP was defined as a neutrophil count of ≥250 cells/mm³ in ascitic fluid. MELD score was based on laboratory parameters determined by UNOS Internet site MELD calculator. Results. In multivariable-adjusted logistic regression models controlling for age, sex, diabetes, and etiology, there was evidence of a positive association of SBP with MELD score: the odds ratio (OR) for SBP for one unit increment of MELD score was 1.06 (95% Cl = 1.02–1.09). MELD score was significantly higher in fatal cases than nonfatal patients (mean age-adjusted score was 32.7 versus 18.4 overall; 34.8 versus 18.0 in SBP patients, and 32.0 versus 18.5 in non-SBP patients; all P < 0.001). Conclusions. In this Albanian sample of hospitalized cirrhotic patients, MELD score was confirmed as a significant predictor of both SBP and fatal outcome.

Characterization of fecal microbial communities in patients with liver cirrhosis

Liver cirrhosis is the pathologic end stage of chronic liver disease. Increasing evidence suggests that gut flora is implicated in the pathogenesis of liver cirrhosis complications. The aim of this study was to characterize the fecal microbial community in patients with liver cirrhosis in comparison with healthy individuals. We recruited 36 patients with liver cirrhosis and 24 healthy controls. The fecal microbial communities was analyzed by way of 454 pyrosequencing of the 16S ribosomal RNA V3 region followed by real-time quantitative polymerase chain reaction. Community-wide changes of fecal microbiota in liver cirrhosis were observed compared with healthy controls. The proportion of phylum Bacteroidetes was significantly reduced (P=0.008), whereas Proteobacteria and Fusobacteria were highly enriched in the cirrhosis group (P=0.001 and 0.002, respectively). Enterobacteriaceae (P=0.001), Veillonellaceae (P=0.046), and Streptococcaceae (P=0.001) were prevalent in patients with cirrhosis at the family level. A positive correlation was observed between Child-Turcotte-Pugh (CTP) score and Streptococcaceae (R=0.386, P=0.02). Lachnospiraceae decreased significantly in patients with cirrhosis (P=0.004) and correlated negatively with CTP score (R=-0.49, P=0.002). Using partial least square discriminate analysis, we identified 149 operational taxonomic units (OTUs) as key phylotypes that responded to cirrhosis, most of which were Lachnospiraceae (65 OTUs), Streptococcaceae (23 OTUs), and Veillonellaceae (21 OTUs).

CONCLUSION

Fecal microbial communities are distinct in patients with cirrhosis compared with healthy individuals. The prevalence of potentially pathogenic bacteria, such as Enterobacteriaceae and Streptococcaceae, with the reduction of beneficial populations such as Lachnospiraceae in patients with cirrhosis may affect prognosis.

Probiotics in hepatology

The paper provides a basic review of intestinal microflora and its importance in liver diseases. The intestinal microflora has many important functions, above all to maintain the microbial barrier against established as well as potential pathogens. Furthermore, it influences the motility and perfusion of the intestinal wall, stimulates the intestinal immune system and therefore also the so-called common mucosal immune system, reducing bacterial translocation and producing vitamins. Immune homeostasis at mucosal level results from a controlled response to intestinal luminal antigens. In liver cirrhosis, there are many changes in its function, mostly an increase in bacterial overgrowth and translocation. In this review, probiotics and their indications in hepatology are generally discussed. According to recent knowledge, these preparations are indicated in clinical practice only for cases of hepatic encephalopathy. Probiotics are able to decrease the permeability of the intestinal wall, and decrease bacterial translocation and endotoxemia in animal models as well as in clinical studies, which is extremely important in the prevention of complications of liver cirrhosis and infection after liver transplantation. Probiotics could limit oxidative and inflammatory liver damage and, in some situations, improve the histological state, and thus non-alcoholic steatohepatitis could be considered as another possible indication.

Association between proton pump inhibitors and spontaneous bacterial peritonitis in cirrhotic patients - a systematic review and meta-analysis

Acid suppressive therapy, in the form of proton pump inhibitor (PPI), is widely used in cirrhotic patients, often in indications which are not clearly justified. PPI facilitates enteric bacterial colonisation, overgrowth and translocation, which might predispose to spontaneous bacterial peritonitis. However, observational studies evaluating the association of PPI and SBP in cirrhotic patients have yielded inconsistent results. We therefore conducted a meta-analysis of relevant clinical studies to determine the nature of this association. Observational studies assessing the association between SBP and PPI in cirrhosis, conducted in adult population and published in all languages, were identified through systematic search in the MEDLINE, EMBASE and manual reviews of all major gastroenterology meeting proceedings up to May 2010. The relevant studies were pooled using traditional meta-analytic techniques with a random-effects model. Four studies were identified and included in the meta-analysis. The pooled analysis, involving a total of 772 patients, found a significant association between the use of PPI and the development of SBP (OR 2.77, 95% CI 1.82-4.23). There was very little degree of heterogeneity as reflected by an I(2) value of 22% and the visual inspection of the funnel plot. There is a potential association between use of PPI and development of SBP. Therefore, PPIs should be used judiciously and only when clearly indicated in cirrhotics. Further studies are essential to clarify this relationship and elucidate the underlying mechanisms.

Increased intestinal permeability as a predictor of bacterial infections in patients with decompensated liver cirrhosis and hemorrhage

BACKGROUND AND AIM

There have been no trials comparing the prophylactic effect of oral quinolone and intravenous cephalosporin antibiotics and elucidating the predictive factors for the occurrence of bacterial infections in cirrhotic patients with gastrointestinal bleeding in Asian-Pacific region.

METHODS

One hundred and thirteen patients with advanced liver cirrhosis and active gastrointestinal hemorrhage were enrolled in our study. The patients were randomly allocated into either the oral ciprofloxacin group (n = 50, 500 mg every 12 h) or the intravenous ceftriaxone group (n = 63, 2.0 g per day for 7 days).

RESULTS

Proven or possible infections were significantly more frequent in the patients in the oral ciprofloxacin group (34.0%) than the intravenous ceftriaxone group (14.3%, P = 0.002). The intestinal permeability index (IPI, mean [SD]) measured the day after admission was significantly higher in the patients with proven or possible infections (1.45 [0.96]) compared with the no infection group (0.46 [0.48], P <0.01). By multivariate analysis, oral ciprofloxacin prophylaxis and higher IPI at the time of inclusion were independent and significant predictors for proven or possible infections. By receiver operating characteristic curve analysis, the best cutoff value of IPI for the prediction of the occurrence of bacterial infection was 0.62%.

CONCLUSIONS

The frequency of proven or possible infections was significantly lower in the intravenous ceftriaxone group compared with the oral ciprofloxacin group. The IPI measured the day after admission is a good clinical parameter predicting the occurrence of infection in these patients.