Effect of cisapride on intestinal bacterial overgrowth and bacterial translocation in cirrhosis

Electroacupuncture reduces blood glucose by regulating intestinal flora in type 2 diabetic mice

BACKGROUND

The development of diabetes is closely related to the gut microbiota in recent studies, which can be influenced by intestinal motility. A few studies report that electroacupuncture (EA) can lower blood glucose. EA can promote colonic motility and influence gut microbes. In this study, we explored the effect of the EA on blood glucose level in mice with type 2 diabetes (T2D) and its mechanism.

METHODS

The T2D mice model, fecal microbiota transplantation mice model, and Kit^W/Wv mice model （Point mutation of mouse W locus encoding kit gene）were used to investigate the effect of EA on blood glucose as well as the mechanism; The blood glucose and insulin resistance level and the intestinal flora were evaluated. The level of intestinal junction protein, inflammatory cytokines in the serum, interstitial cells of Cajal content, and colonic motility were detected. Lastly, the IKKβ/NF-κB-JNK-IRS-1-AKT pathway was explored.

RESULTS

EA lowered the blood glucose level, altered the gut microbiota, and promoted colonic motility in T2D mice. EA-altered microbiota decreased the blood glucose level and insulin resistance in the antibiotics-treated diabetic mice. EA increased tight junction protein, lowered inflammatory factors, and regulated the IKKβ/NF-κB-JNK-IRS-1-AKT pathway in the liver and muscles. EA could not reduce the blood glucose and regulated gut microbiota in the Kit^W/Wv mice model.

CONCLUSIONS

EA promoted intestinal motility to regulate the intestinal flora, thereby reducing the level of systemic inflammation, and ultimately lowering the blood glucose by the IKKβ/NF-κB-JNK-IRS-1-AKT signal pathway.

The Role of Gut Microbiota in Some Liver Diseases: From an Immunological Perspective

Gut microbiota is a microecosystem composed of various microorganisms. It plays an important role in human metabolism, and its metabolites affect different tissues and organs. Intestinal flora maintains the intestinal mucosal barrier and interacts with the immune system. The liver is closely linked to the intestine by the gut-liver axis. As the first organ that comes into contact with blood from the intestine, the liver will be deeply influenced by the gut microbiota and its metabolites, and the intestinal leakage and the imbalance of the flora are the trigger of the pathological reaction of the liver. In this paper, we discuss the role of gut microbiota and its metabolites in the pathogenesis and development of autoimmune liver diseases((including autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis), metabolic liver disease such as non-alcoholic fatty liver disease, cirrhosisits and its complications, and liver cancer from the perspective of immune mechanism. And the recent progress in the treatment of these diseases was reviewed from the perspective of gut microbiota.

The Association Between Proton Pump Inhibitor Exposure and Key Liver-Related Outcomes in Patients With Cirrhosis: A Veterans Affairs Cohort Study

BACKGROUND & AIMS

The impact of proton pump inhibitory (PPI) medications on adverse outcomes in cirrhosis remains controversial. We aimed to evaluate the association between PPI exposure and all-cause mortality, infection, and decompensation in a large national cohort.

METHODS

This was a retrospective study of patients with cirrhosis in the Veterans Health Administration. PPI exposure was classified as a time-updating variable from the index time of the cirrhosis diagnosis. Inverse probability treatment weighting-adjusted Cox regression was performed with additional adjustment for key time-varying covariates, including cardiovascular comorbidities, gastrointestinal bleeding (GIB), and statin exposure.

RESULTS

The study included 76,251 patients, 23,628 of whom were on a PPI at baseline. In adjusted models, binary (yes/no) PPI exposure was associated with reduced hazard of all-cause mortality in patients with hospitalization for GIB (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.84-0.91; P < .001) but had no significant association in all others (HR, 0.99; 95% CI, 0.97-1.02; P = .58). However, cumulative PPI exposure was associated with increased mortality in patients without hospitalization for GIB (HR, 1.07 per 320 mg-months [omeprazole equivalents]; 95% CI, 1.06-1.08; P < .001). PPI exposure was significantly associated with severe infection (HR, 1.21; 95% CI, 1.18-1.24; P < .001) and decompensation (HR, 1.64; 95% CI, 1.61-1.68; P < .001). In a cause-specific mortality analysis, PPI exposure was associated with increased liver-related mortality (HR, 1.23; 95% CI, 1.19-1.28) but with decreased nonliver-related mortality (HR, 0.88; 95% CI, 0.85-0.91).

CONCLUSIONS

PPI exposure is associated with increased risk of infection and decompensation in cirrhosis, which may mediate liver-related mortality. However, PPI use was associated with reduced all-cause mortality in those with prior GIB, suggesting benefit in the presence of an appropriate indication.

Preventing Bacterial Translocation in Patients with Leaky Gut Syndrome: Nutrition and Pharmacological Treatment Options

Leaky gut syndrome is a medical condition characterized by intestinal hyperpermeability. Since the intestinal barrier is one of the essential components maintaining homeostasis along the gastrointestinal tract, loss of its integrity due to changes in bacterial composition, decreased expression levels of tight junction proteins, and increased concentration of pro-inflammatory cytokines may lead to intestinal hyperpermeability followed by the development of gastrointestinal and non-gastrointestinal diseases. Translocation of microorganisms and their toxic metabolites beyond the gastrointestinal tract is one of the fallouts of the leaky gut syndrome. The presence of intestinal bacteria in sterile tissues and distant organs may cause damage due to chronic inflammation and progression of disorders, including inflammatory bowel diseases, liver cirrhosis, and acute pancreatitis. Currently, there are no medical guidelines for the treatment or prevention of bacterial translocation in patients with the leaky gut syndrome; however, several studies suggest that dietary intervention can improve barrier function and restrict bacteria invasion. This review contains current literature data concerning the influence of diet, dietary supplements, probiotics, and drugs on intestinal permeability and bacterial translocation.

Proton pump inhibitors use and risk of developing spontaneous bacterial peritonitis in cirrhotic patients: A systematic review and meta-analysis

Background

Spontaneous bacterial peritonitis (SBP) is one of the most common infectious diseases in patients with cirrhosis and is associated with serious prognosis. A prevailing dogma posits that SBP is exacerbated by the frequent use of proton pump inhibitors (PPIs).

Aims

To re-assess the association between PPIs use and SBP incidence with larger and better-quality data.

Method

The studies were identified by searching Proquest, Medline, and Embase for English language articles published between January 2008 and March 2020 using the following keywords alone or in combination: anti-ulcer agent, antacid, proton pump inhibitor, proton pumps, PPI, omeprazole, rabeprazole, lansoprazole, pantoprazole, esomeprazole, peritonitis, spontaneous bacterial peritonitis, SBP, ascites, cirrhosis, ascitic and cirrhotic. Three authors critically reviewed all of the studies retrieved and selected those judged to be the most relevant. Preferred

Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was followed. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Sub-group analyses were done to decrease the heterogeneity.

Results

A total of twenty-three studies: seven case–control, and sixteen cohorts, involving 10,386 patients were analyzed. The overall results showed a statistically significant association between SBP and PPIs use (pooled odds ratio (OR): 1.80, 95% CI of 1.41 to 2.31). Substantial heterogeneity was observed. On subgroup analysis involving cohort studies, the association was weaker (OR: 1.55 with 95% CI of 1.16 to 2.06 p < 0.00001) but still statistically significant and with high heterogeneity (Chi²p = 57.68; I² = 74%). For case–control studies, the OR was 2.62 with a 95% CI of 1.94 to 3.54. The funnel plot was asymmetric and Egger’s test confirmed asymmetry suggesting publication bias (intercept = − 0.05, SE = 0.27, P = 0.850 two-tailed).

Conclusion

This meta-analysis sheds light on the conflicting results raised by previous studies regarding the association of SBP with PPIs use. Our meta-analysis showed that there is a weak association, although statistically significant, between SBP and PPIs use. However, the magnitude of the possible association diminished when analysis focused on higher quality data that were more robust. Thus, this updated meta-analysis suggests judicious use of PPIs among cirrhotic patients with ascites.

Gut Microbiota, Peroxisome Proliferator-Activated Receptors, and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. HCC incidence rate is sixth and mortality is fourth worldwide. However, HCC pathogenesis and molecular mechanisms remain unclear. The incidence of HCC is associated with genetic, environmental, and metabolic factors. The role of gut microbiota in the pathogenesis of HCC has attracted researchers’ attention because of anatomical and functional interactions between liver and intestine. Studies have demonstrated the involvement of gut microbiota in the development of HCC and chronic liver diseases, such as alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), and liver cirrhosis. Peroxisome proliferator-activated receptors (PPARs) are a group of receptors with diverse biological functions. Natural and synthetic PPAR agonists show potential for treatment of NAFLD, liver fibrosis, and HCC. Recent studies have demonstrated that PPARs take part in gut microbiota inhabitation and adaptation. This manuscript reviews the role of gut microbiota in the development of HCC and precancerous diseases, the role of PPARs in modulation of gut microbiota and HCC, and potential of gut microbiota for HCC diagnosis and treatment.

Current Status and Prospects of Spontaneous Peritonitis in Patients with Cirrhosis

Spontaneous bacterial peritonitis (SBP) is a common cirrhotic ascites complication which exacerbates the patient's condition. SBP is caused by gram-negative bacilli and, to a lesser extent, gram-positive cocci. Hospital-acquired infections show higher levels of drug-resistant bacteria. Geographical location influences pathogenic bacteria distribution; therefore, different hospitals in the same country record different bacteria strains. Intestinal changes and a weak immune system in patients with liver cirrhosis lead to bacterial translocation thus causing SBP. Early diagnosis and timely treatment are important in SBP management. When the treatment effect is not effective, other rare pathogens should be explored.

Kansuiphorin C and Kansuinin A ameliorate malignant ascites by modulating gut microbiota and related metabolic functions

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia kansui is a toxic Chinese herbal medicine and exhibits promising treatment to the malignant ascites (MA) in its traditional use. Ingenane-type and jastrophane-type diterpenes are demonstrated to be responsible for the toxicity and efficacy of kansui. Two representative compounds, kansuiphorin C (KPC) and kansuinin A (KA) in each type were proved to effectively reduce the ascites. The biological and toxicological effects are closely associated with the gastrointestinal tract, but the possible mechanism and related metabolic functions of KPC and KA treating MA through modulating the gut microbiota remain unclear.

AIM OF THE STUDY

To investigate the possible mechanism and related metabolism of KPC and KA ameliorating malignant ascites through modulating gut microbiota.

MATERIALS AND METHODS

MA rats and normal rats were divided into different groups and administrated with KPC, KA, and positive drug, respectively. 16S rDNA gene sequencing and metagenomes analysis combined with the quantification of short-chain fatty acids of feces were performed to reflect the modulation of gut microbiota. Then, the metabolites of KPC and KA in rat feces under the normal and pathological circumstances were detected by ultra-fast liquid chromatography coupled with MS/MS detector (UFLC-MS/MS) to explore the in-vivo bacterial biotransformation.

RESULTS

KPC and KA were modulatory compounds for gut microbiota. The richness of Lactobacillus and the decreased abundance of Helicobacter involved in the carbohydrate metabolism and amino acid metabolism could be responsible for their prohibitory effects on malignant ascites. KPC exhibited stronger modulation of gut microbiota through making the abundance of Helicobacter about 3.5 times lower than KA. Besides, in-vivo microbial biotransformation of KPC and KA contained oxidation, hydrolysis, dehydration, and methylation to form metabolites of lower polarity. Besides, at the dosage of 10 mg kg^-1, the toxicity of both compounds had weaker influences on the gut microbiota of normal rats.

CONCLUSION

KPC and KA could ameliorate malignant ascites by modulating gut microbiota mainly containing the increase of Lactobacillus and the decrease of Helicobacter and related carbohydrate and amino acid metabolism, providing a basis for their promising clinical usage.

Role of Gut Dysbiosis in Liver Diseases: What Have We Learned So Far?

Accumulating evidence supports that gut dysbiosis may relate to various liver diseases. Alcoholics with high intestinal permeability had a decrease in the abundance of Ruminnococcus. Intestinal dysmotility, increased gastric pH, and altered immune responses in addition to environmental and genetic factors are likely to cause alcohol-associated gut microbial changes. Alcohol-induced dysbiosis may be associated with gut barrier dysfunction, as microbiota and their products modulate barrier function by affecting epithelial pro-inflammatory responses and mucosal repair functions. High levels of plasma endotoxin are detected in alcoholics, in moderate fatty liver to advanced cirrhosis. Decreased abundance of Faecalibacterium prausnitzii, an anti-inflammatory commensal, stimulating IL-10 secretion and inhibiting IL-12 and interferon-γ expression. Proteobacteria, Enterobacteriaceae, and Escherichia were reported to be increased in NAFLD (nonalcoholic fatty liver disease) patients. Increased abundance of fecal Escherichia to elevated blood alcohol levels in these patients and gut microbiota enriched in alcohol-producing bacteria produce more alcohol (alcohol hypothesis). Some undetermined pathological sequences related to gut dysbiosis may facilitate energy-producing and proinflammatory conditions for the progression of NAFLD. A shortage of autochthonous non-pathogenic bacteria and an overgrowth of potentially pathogenic bacteria are common findings in cirrhotic patients. The ratio of the amounts of beneficial autochthonous taxa (Lachnospiraceae + Ruminococaceae + Veillonellaceae + Clostridiales Incertae Sedis XIV) to those of potentially pathogenic taxa (Enterobacteriaceae + Bacteroidaceae) was low in those with early death and organ failure. Cirrhotic patients with decreased microbial diversity before liver transplantation were more likely to develop post-transplant infections and cognitive impairment related to residual dysbiosis. Patients with PSC had marked reduction of bacterial diversity. Enterococcus and Lactobacillus were increased in PSC patients (without liver cirrhosis.) Treatment-naive PBC patients were associated with altered composition and function of gut microbiota, as well as a lower level of diversity. As serum anti-gp210 antibody has been considered as an index of disease progression, relatively lower species richness and lower abundance of Faecalibacterium spp. in gp210-positive patients are interesting. The dysbiosis-induced altered bacterial metabolites such as a hepatocarcinogenesis promotor DCA, together with a leaky gut and bacterial translocation. Gut protective Akkermansia and butyrate-producing genera were decreased, while genera producing-lipopolysaccharide were increased in early hepatocellular carcinoma (HCC) patients.

Plasma diamine oxidase level predicts 6-month readmission for patients with hepatitis B virus-related decompensated cirrhosis

Background and aims

Hepatitis B virus-related decompensated cirrhosis is difficult to cure but has a high readmission rate due to multiple complications. Our aim was to investigate the diagnostic potential value of plasma diamine oxidase (DAO) for 6-month readmission of patients with HBV-related decompensated cirrhosis.

Methods

A total of 135 patients with HBV-related decompensated cirrhosis were prospectively collected at the onset of discharge of hospital, and then were followed up for at least 6 months with the readmission as the primary outcome. The plasma DAO level was measured using enzyme linked immunosorbent assay. In addition, 120 age and sex matched patients with HBV-related compensated cirrhosis were included as controls.

Results

A total of 36 patients (36.7%) with decompensated cirrhosis admitted to hospital during the 6-month follow up. The plasma DAO level of readmission group [21.1 (14.5; 29.0) ng/ml] was significantly higher than that in the non-readmission group [12.7 (9.3; 18.0) ng/mL, P < 0.001]. Multivariate analysis showed that the plasma DAO level (HR = 1.102, P < 0.05) and hepatic encephalopathy (HE) (HR = 5.018, P < 0.05) were independent factors for 6-month readmission of decompensated cirrhosis. DAO level showed higher area under the curve of receiver operating characteristic (AUROC) than HE (0.769 vs. 0.598, P < 0.05) and Child-Pugh-Turcotte (CPT) score (0.769 vs. 0.652, P < 0.05) for predicting 6-month readmission rate, with the best cut-off value as 19.7 ng/mL. Furthermore, plasma DAO level (HR = 1.184, P < 0.05) was an independent factor and has the higher AUROC than CPT score for the onset of recurrent HE (0.905 vs. 0.738, P < 0.05) during the 6-month follow up.

Conclusions

Plasma DAO level > 19.7 ng/mL predicts high rate of 6-month readmission in patients with HBV-related decompensated cirrhosis.

Microbiota-Immune Interaction in the Pathogenesis of Gut-Derived Infection

Gut-derived infection is among the most common complications in patients who underwent severe trauma, serious burn, major surgery, hemorrhagic shock or severe acute pancreatitis (SAP). It could cause sepsis and multiple organ dysfunction syndrome (MODS), which are regarded as a leading cause of mortality in these cases. Gut-derived infection is commonly caused by pathological translocation of intestinal bacteria or endotoxins, resulting from the dysfunction of the gut barrier. In the last decades, the studies regarding to the pathogenesis of gut-derived infection mainly focused on the breakdown of intestinal epithelial tight junction and increased permeability. Limited information is available on the roles of intestinal microbial barrier in the development of gut-derived infection. Recently, advances of next-generation DNA sequencing techniques and its utilization has revolutionized the gut microecology, leading to novel views into the composition of the intestinal microbiota and its connections with multiple diseases. Here, we reviewed the recent progress in the research field of intestinal barrier disruption and gut-derived infection, mainly through the perspectives of the dysbiosis of intestinal microbiota and its interaction with intestinal mucosal immune cells. This review presents novel insights into how the gut microbiota collaborates with mucosal immune cells to involve the development of pathological bacterial translocation. The data might have important implication to better understand the mechanism underlying pathological bacterial translocation, contributing us to develop new strategies for prevention and treatment of gut-derived sepsis.

Microbial Infections as a Trigger for Acute-on-Chronic Liver Failure: A Review

Microbial infection is an important cause of acute-on-chronic liver failure (ACLF), which is a syndrome that results in multiple organ dysfunction or failure and is accompanied by an increased short-term risk of mortality. Early detection and treatment of microbial infection can effectively reduce the mortality of patients with ACLF. However, antimicrobial resistance has recently increased due to the increased use of antimicrobial agents. Therefore, it is important to choose appropriate antibiotics and antifungal agents for early prevention or treatment of patients with microbial infection and ACLF to reduce the occurrence of drug resistance and to reduce patient mortality. This review summarizes the current status in the understanding of the epidemiology, pathogenesis, early diagnosis, treatment, and strategies for prevention of microbial infection in patients with ACLF.

[Spontaneous Bacterial Peritonitis]

Spontaneous bacterial peritonitis (SBP) is defined as bacterial infections that occur in patients with cirrhosis and ascites without any significant intraperitoneal infection, accounting for approximately 10-30% of bacterial infections in hospitalized patients. SBP develops in patients with liver cirrhosis because bacterial translocations are increased by changes in the intestinal bacteria and mucosal barriers. In addition, the decreased host immune response cannot remove the bacteria and their products. The most common cause of SBP is Gram-negative bacteria, such as Escherichia coli and Klebsiella species, and infections by Gram-positive bacteria are increasing. SBP is diagnosed by the presence of >250 polymorphonuclear leukocyte/mm³ in ascites after paracentesis. If SBP is diagnosed, empirical antibiotic therapy should be started immediately. Empirical antibiotic treatment should distinguish between community acquired infections and nosocomial infections. Cirrhotic patients with gastrointestinal bleeding or low ascitic protein concentrations should consider primary prevention and those who recover from SBP should consider secondary prevention. This review describes the pathophysiology, diagnosis, treatment, and prevention of SBP.

The role of gut microbiota in liver disease development and treatment

Liver cancer is the sixth most common cancer worldwide, and the third most common cause of cancer-related death. Hepatocellular carcinoma (HCC), which accounts for more than 90% of primary liver cancers, is an important public health problem. In addition to cirrhosis caused by hepatitis B viral (HBV) or hepatitis C viral (HCV) infection, non-alcoholic fatty liver disease (NAFLD) is becoming a major risk factor for liver cancer because of the prevalence of obesity. Non-alcoholic steatohepatitis (NASH) will likely become the leading indication for liver transplantation in the future. It is well recognized that gut microbiota is a key environmental factor in the pathogenesis of liver disease and cancer. The interplay between gut microbiota and liver disease has been investigated in animal and clinical studies. In this article, we summarize the roles of gut microbiota in the development of liver disease as well as gut microbiota-targeted therapies.

Spontaneous bacterial peritonitis - therapeutic challenges in the era of increasing drug resistance of bacteria

Spontaneous bacterial peritonitis (SBP) is one of the most common bacterial infections in patients with liver cirrhosis and it significantly contributes to the deterioration of the prognosis and increased risk of mortality. Previous data suggested that the most common pathogens causing SBP are G-negative aerobic bacteria and treatment recommended by the international guidelines (EASL, AASLD) is highly effective.

In recent years, due to the widespread use of antibiotic prophylaxis and the increased frequency of hospitalization along with the use of invasive procedures in patients with cirrhosis, the involvement of Gram-positive cocci and multi-drug resistant bacteria in the etiology of SBP is increasing. This is related to the lowering of the effectiveness of the first-line therapy used so far and worsening of the prognosis, increasing in-hospital mortality. In this work we summarize current data on the characteristics of pathogens responsible for SBP in the context of currently recommended treatment regimens.

Effect of Proton Pump Inhibitors on Mortality in Patients with Cirrhosis and Spontaneous Bacterial Peritonitis

INTRODUCTION AND AIM

Spontaneous bacterial peritonitis (SBP) is a life-threatening infection in patients with cirrhosis. However, it is unknown whether patients with SBP and cirrhosis who do not have active gastrointestinal bleeding have a poorer prognosis if treated with proton pump inhibitors (PPI).

MATERIAL AND METHODS

We used the Taiwan National Health Insurance Database to identify 858 patients with SBP and cirrhosis who were administered PPIs and hospitalized between January 1, 2010, and December 31, 2013. One-to-two propensity score matching was performed to select a comparison group based on age, gender, and comorbidities. All patients obtained follow-up for 1 year.

RESULTS

The overall 30-day, 90-day, and 1-year mortality was 27.9%, 49.0%, and 73.7%, respectively, in the PPI group and 25.6%, 43.8%, and 67.2%, respectively, in the non-PPI group. After adjusting the Cox regression model for age, gender, and comorbidities, the hazard ratios for PPIs regarding 30-day, 30- to 90-day, and 90-day to 1-year mortality were 1.074 (95% CI 0.917-1.257, P = 0.377), 1.390 (95% CI 1.154-1.673, P = 0.001), and 1.297 (95% CI 1.099- 1.531, P = 0.002), respectively.

CONCLUSIONS

PPIs did not increase the short-term mortality of patients with SBP and cirrosis who did not have active gastrointestinal bleeding, but PPIs increased the long-term mortality risk. For these patients, physicians should discontinue PPIs as early as possible.

Small Bowel Transit and Altered Gut Microbiota in Patients With Liver Cirrhosis

Disturbance of the gut microbiota is common in liver cirrhosis (LC) patients, the underlying mechanisms of which are yet to be unfolded. This study aims to explore the relationship between small bowel transit (SBT) and gut microbiota in LC patients. Cross-sectional design was applied with 36 LC patients and 20 healthy controls (HCs). The gut microbiota was characterized by 16S rRNA gene sequencing. The Firmicutes/Bacteroidetes (F/B) ratio and the Microbial Dysbiosis index (MDI) were used to evaluate the severity of microbiota dysbiosis. The scintigraphy method was performed in patients to describe the objective values of SBT. Patients were then subdivided according to the Child–Pugh score (threshold = 5) or SBT value (threshold = 0.6) for microbiota analysis. LC patients were characterized by an altered gut microbiota; F/B ratios and MDI were higher than HC in both Child_5 (14.00 ± 14.69 vs. 2.86 ± 0.99, p < 0.01; 0.49 ± 0.80 vs. -0.47 ± 0.69, p < 0.01) and Child_5+ (15.81 ± 15.11 vs. 2.86±0.99, p < 0.01; 1.11 ± 1.05 vs. -0.47 ± 0.69, p < 0.01) sub-groups in patients. Difference in the gut microbiota between Child_ 5 and Child_5+ patients was inappreciable, but the SBT was relatively slower in Child_5+ patients (43 ± 26% vs. 80 ± 15%, p < 0.05). Compared with the Child–Pugh score indicators, SBT showed stronger associations with bacterial genera. A clear difference in the gut microbiota was observed between SBT_0.6- and SBT_0.6+ patients [Pr(>F) = 0.0068, pMANOVA], with higher F/B ratios and MDI in SBT_0.6- patients (19.71 ± 16.62 vs. 7.33 ± 6.65, p < 0.01; 1.02 ± 0.97 vs. 0.20 ± 0.58, p < 0.01). Similar results were observed between the SBT_0.6- and SBT_0.6+ sub-groups of patients with normal liver function and a Child–Pugh score of 5. SBT was negatively correlated with both the F/B ratio and MDI (r = -0.34, p < 0.05; r = -0.38, p < 0.05). Interestingly, an increased capacity for the inferred pathway “bacterial invasion of epithelial cells” in patients, was highly negatively correlated with SBT (r = -0.57, p < 0.01). The severity of microbiota dysbiosis in LC patients depends on SBT rather than Child–Pugh score. SBT per se might be significantly related to the gut microbiota abnormalities observed in patients with LC.

Influence of proton pump inhibitors in the development of spontaneous bacterial peritonitis

AIM

To investigate whether the use of proton pump inhibitors (PPIs) increases the incidence of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis and ascites.

METHODS

An historical cohort study was carried out in cirrhotic outpatients with ascites followed in a specialized clinic at a tertiary hospital in Southern Brazil. Patient charts were reviewed to collect information on the variables of interest as the use of PPIs. Primary outcome was defined as development of SBP during the study period. SBP was diagnosed based on ascitic fluid polymorphonuclear cell count ≥ 250 cells/mm³ without evidence of an intra-abdominal, surgically treatable source of infection.

RESULTS

Of 738 cirrhotic patients, 582 (58.2% male) were enrolled, with mean age of 53.6 ± 12 years. Hepatitis C virus infection (36.2%) and alcohol abuse (25.6%) were the main etiologies of cirrhosis. The presence of ascites was detected in 299 (51.4%) patients during the development of the study. Nineteen patients with previous diagnosis of SBP undergoing secondary prophylaxis and 22 patients with insufficient PPI data were further excluded. Of 258 patients with ascites, 151 used PPIs, and 34 developed SBP (22.5%). Among 107 non-users of PPIs, 23 developed SBP (21.5%) (HR = 1.44, 95%CI: 0.85-2.47, P = 0.176). The median follow-up time of patients using PPI was 27 mo vs 32 mo for non-users. Univariate analysis of the risk factors associated with the development of SBP revealed a significant association of SPB with the severity of liver disease according to the Child-Turcotte-Pugh (CTP) score. Multivariate analysis confirmed that CTP score was the only independent variable influencing the occurrence of SBP. Survival at 60 mo (Kaplan-Meier analysis) was similar in users and non-users of PPI, independently of the presence of SBP (58.4% vs 62.7% respectively, P = 0.66). For patients with SBP, survival at 60 mo was 55.1%, vs 61.7% in patients without SBP (P = 0.34).

CONCLUSION

In conclusion, the rate of SBP was not significantly different in users or non-users of PPIs in this cohort of cirrhotic with ascites.

Mosapride Stabilizes Intestinal Microbiota to Reduce Bacterial Translocation and Endotoxemia in CCl4-Induced Cirrhotic Rats

BACKGROUND

Impaired intestinal motility may lead to the disruption of gut microbiota equilibrium, which in turn facilitates bacterial translocation (BT) and endotoxemia in cirrhosis. We evaluated the influence of mosapride, a prokinetic agent, on BT and DNA fingerprints of gut microbiota in cirrhotic rats.

METHODS

A rat model of cirrhosis was set up via subcutaneous injection of carbon tetrachloride (CCl₄). The portal pressure, liver and intestinal damage, plasma endotoxin, BT, and intestinal transit rate (ITR) of cirrhotic rats were determined. Fecal DNA fingerprints were obtained by ERIC-PCR. The expressions of tight junction proteins were evaluated by western blotting.

RESULTS

Mosapride treatment to cirrhotic rats significantly reduced the plasma endotoxin level and incidence of BT, accompanied by increased ITR. Cirrhotic rats (including those treated with mosapride) suffered from BT exhibited significantly lower ITR than those who are free of BT. Pearson coefficient indicated a significant and negative correlation between the plasma endotoxin level and ITR. The genomic fingerprints of intestinal microbiota from the three groups fell into three distinctive clusters. In the mosapride-treated group, Shannon's index was remarkably increased compared to the model group. Significantly positive correlation was detected between Shannon's index and ITR. Mosapride did not improve hepatic and intestinal damages and ileal expressions of occludin and ZO-1.

CONCLUSIONS

Mosapride significantly increases intestinal motility in cirrhotic rats, thus to recover the disordered intestinal microbiota, finally resulting in decreased plasma endotoxin and BT.

The gut microbiome and liver cancer: mechanisms and clinical translation

Hepatocellular carcinoma (HCC) is the third leading cause of worldwide cancer mortality. HCC almost exclusively develops in patients with chronic liver disease, driven by a vicious cycle of liver injury, inflammation and regeneration that typically spans decades. Increasing evidence points towards a key role of the bacterial microbiome in promoting the progression of liver disease and the development of HCC. Here, we will review mechanisms by which the gut microbiota promotes hepatocarcinogenesis, focusing on the leaky gut, bacterial dysbiosis, microbe-associated molecular patterns and bacterial metabolites as key pathways that drive cancer-promoting liver inflammation, fibrosis and genotoxicity. On the basis of accumulating evidence from preclinical studies, we propose the intestinal-microbiota-liver axis as a promising target for the simultaneous prevention of chronic liver disease progression and HCC development in patients with advanced liver disease. We will review in detail therapeutic modalities and discuss clinical settings in which targeting the gut-microbiota-liver axis for the prevention of disease progression and HCC development seems promising.

Bacterial translocation markers in liver cirrhosis

Bacterial translocation (BT) is an important mechanism in the development of infection in liver cirrhosis. The migration and colonization of bacteria and/or bacterial products from the bowel to mesenteric lymph nodes is a controlled process in healthy persons. Increased intestinal permeability, bacterial overgrowth and defect of gut-associated lymphatic tissue promote impaired BT in cirrhotics. We reviewed the reports on markers used for the evaluation of BT published between 1987 and 2016. We focused on the clinical consequences of BT in cirrhosis, as indicated by the values of the BT markers. Patients with cirrhosis are reported to have elevated levels of surrogate markers associated with BT compared with controls. The most widely used BT parameters are C-reactive protein, procalcitonin, bacterial DNA, endotoxin or lipopolysaccharide, lipopolysaccharide binding protein, calprotectin, and bactericidal/permeability increasing protein. High levels of these factors in serum and/or ascitic fluid in humans may be associated with advanced liver disease, hemodynamic instability, high levels of proinflammatory cytokines, susceptibility to the development of severe or recurrent infections, acute-on-chronic liver failure, hepatic encephalopathy, hepatorenal syndrome and poor prognosis during follow up. In conclusion, high levels of BT markers are associated with a high inflammatory response, increased complications of liver cirrhosis and occasionally high fatality rates.

Gastrointestinal Motility Disorders and Their Clinical Implications in Cirrhosis

Gastrointestinal motility is impaired in a substantial proportion of patients with cirrhosis. Cirrhosis-related autonomic neuropathy, increased nitric oxide production, and gut hormonal changes have been implicated. Oesophageal dysmotility has been associated with increased frequency of abnormal gastro-oesophageal reflux. Impaired gastric emptying and accommodation may result in early satiety and may have an impact on the nutritional status of these patients. Small intestinal dysmotility might be implicated in small intestinal bacterial overgrowth and increased bacterial translocation. The latter has been implicated in the pathophysiology of hepatic encephalopathy and spontaneous bacterial peritonitis. Enhanced colonic motility is usually associated with the use of lactulose. Pharmacological interventions aiming to alter gastrointestinal motility in cirrhosis could potentially have a beneficial effect reducing the risk of hepatic decompensation and improving prognosis.

Fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 reduces bacterial translocation in rats treated with carbon tetrachloride

Probiotics can prevent pathological bacterial translocation by modulating intestinal microbiota and improving the gut barrier. The aim was to evaluate the effect of a fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 on bacterial translocation in rats with carbon tetrachloride (CCl₄)-induced cirrhosis. Sprague-Dawley rats treated with CCl₄ were randomized into a probiotic group that received fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 in drinking water or a water group that received water only. Laparotomy was performed one week after ascites development. We evaluated bacterial translocation, intestinal microbiota, the intestinal barrier and cytokines in mesenteric lymph nodes and serum. Bacterial translocation decreased and gut dysbiosis improved in the probiotic group compared to the water group. The ileal β-defensin-1 concentration was higher and ileal malondialdehyde levels were lower in the probiotic group than in water group. There were no differences between groups in serum cytokines but TNF-α levels in mesenteric lymph nodes were lower in the probiotic group than in the water group. Fermented milk containing Lactobacillus paracasei subsp. paracasei CNCM I-1518 decreases bacterial translocation, gut dysbiosis and ileal oxidative damage and increases ileal β-defensin-1 expression in rats treated with CCl₄, suggesting an improvement in the intestinal barrier integrity.

Bacterial translocation in critical illness

Bacterial translocation involves the passage of intestinal bacteria to extraintestinal sites and has been shown to increase morbidity and mortality in critical illness. This review outlines the pathophysiology of bacterial translocation, host defence mechanisms, and reviews the evidence for the clinical management of critically ill patients in order to minimise the negative outcomes associated with bacterial translocation.

Intestinal permeability in a patient with liver cirrhosis

Liver cirrhosis is a worldwide public health problem, and patients with this disease are at high risk of developing complications, bacterial translocation from the intestinal lumen to the mesenteric nodes, and systemic circulation, resulting in the development of severe complications related to high mortality rate. The intestinal barrier is a structure with a physical and biochemical activity to maintain balance between the external environment, including bacteria and their products, and the internal environment. Patients with liver cirrhosis develop a series of alterations in different components of the intestinal barrier directly associated with the severity of liver disease that finally increased intestinal permeability. A "leaky gut" is an effect produced by damaged intestinal barrier; alterations in the function of tight junction proteins are related to bacterial translocation and their products. Instead, increasing serum proinflammatory cytokines and hemodynamics modification, which results in the appearance of complications of liver cirrhosis such as hepatic encephalopathy, variceal hemorrhage, bacterial spontaneous peritonitis, and hepatorenal syndrome. The intestinal microbiota plays a fundamental role in maintaining the proper function of the intestinal barrier; bacterial overgrowth and dysbiosis are two phenomena often present in people with liver cirrhosis favoring bacterial translocation. Increased intestinal permeability has an important role in the genesis of these complications, and treating it could be the base for prevention and partial treatment of these complications.

Dysbiosis of small intestinal microbiota in liver cirrhosis and its association with etiology

Cirrhosis-associated duodenal dysbiosis is not yet clearly defined. In this research, duodenal mucosal microbiota was analyzed in 30 cirrhotic patients and 28 healthy controls using 16S rRNA gene pyrosequencing methods. The principal coordinate analysis revealed that cirrhotic patients were colonized by remarkable different duodenal mucosal microbiota in comparison with controls. At the genus level, Veillonella, Megasphaera, Dialister, Atopobium, and Prevotella were found overrepresented in cirrhotic duodenum. And the duodenal microbiota of healthy controls was enriched with Neisseria, Haemophilus, and SR1 genera incertae sedis. On the other hand, based on predicted metagenomes analyzed, gene pathways related to nutrient absorption (e.g. sugar and amino acid metabolism) were highly abundant in cirrhosis duodenal microbiota, and functional modules involved in bacterial proliferation and colonization (e.g. bacterial motility proteins and secretion system) were overrepresented in controls. When considering the etiology of cirrhosis, two operational taxonomic units (OTUs), OTU-23 (Neisseria) and OTU-36 (Gemella), were found discriminative between hepatitis-B-virus related cirrhosis and primary biliary cirrhosis. The results suggest that the structure of duodenal mucosa microbiota in cirrhotic patients is dramatically different from healthy controls. The duodenum dysbiosis might be related to alterations of oral microbiota and changes in duodenal micro-environment.

Relationship between gastrointestinal micro-ecological imbalance and development of gastric cancer

The human body and microorganisms present in the body form a symbiotic system as the relationship between eukaryotes and prokaryotes. Therefore, it is not enough to study human diseases only in terms of human body. Recent studies have pointed out that microorganisms are involved in the occurrence of a large number of malignant tumors. According to a conservative estimate, at least 15% of cancer cases are associated with infectious agents. Gastric cancer is the second major cause of global cancer deaths. For a long period of time, researchers believe that Helicobacter pylori associated with chronic gastritis is the strongest risk factor for the occurrence of gastric cancer. However, with the progress of molecular biology research, it has been found that there is a close interaction between the large microbial flora and Helicobacter pylori in the gastrointestinal tract. The changes of microbial community composition have important effects on the formation, development and intervention of gastric cancer. This article will review the occurrence and development of gastrointestinal microorganism and gastric cancer.

Changes of Intestinal Functions in Liver Cirrhosis

Background

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

Summary

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

Key Messages

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

Changes of Intestinal Functions in Liver Cirrhosis

BACKGROUND

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

SUMMARY

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

KEY MESSAGES

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

Effect of artesunate supplementation on bacterial translocation and dysbiosis of gut microbiota in rats with liver cirrhosis

AIM: To evaluate the effect of artesunate (AS) supplementation on bacterial translocation (BT) and gut microbiota in a rat model of liver cirrhosis.

METHODS: Fifty-four male Sprague-Dawley rats were randomly divided into a normal control group (N), a liver cirrhosis group (M) and a liver cirrhosis group intervened with AS (MA). Each group was sampled at 4, 6 and 8 wk. Liver cirrhosis was induced by injection of carbon tetrachloride (CCl₄), intragastric administration of 10% ethanol, and feeding a high fat diet. Rats in the MA group were intragastrically administered with AS (25 mg/kg body weight, once daily). Injuries of the liver and intestinal mucosa were assessed by hematoxylin-eosin or Masson’s trichrome staining. Liver index was calculated as a ratio of the organ weight (g) to body weight (g). The gut microbiota was examined by automated ribosomal intergenic-spacer analysis of fecal DNA. BT was assessed by standard microbiological techniques in the blood, mesenteric lymph nodes (MLNs), liver, spleen, and kidney.

RESULTS: Compared to group N, the body weight was reduced significantly in groups M and MA due to the development of liver cirrhosis over the period of 8 wk. The body weight was higher in group MA than in group M. The liver indices were significantly elevated at 4, 6 and 8 wk in groups M and MA compared to group N. AS supplementation partially decreased the liver indices in group MA. Marked histopathologic changes in the liver and small intestinal mucosa in group M were observed, which were alleviated in group MA. Levels of pro-inflammatory interleukin-6 and tumor necrosis factor-α were significantly elevated at 8 wk in ileal homogenates in group M compared to group N, which were decreased after AS supplementation in group MA. The dysbiosis of gut microbiota indicated by the mean diversity (Shannon index) and mean similarity (Sorenson index) was severe as the liver cirrhosis developed, and AS supplementation had an apparent intervention effect on the dysbiosis of gut microbiota at 4 wk. The occurrence of BT was increased in the liver of group M compared to that of group N. AS supplementation reduced BT in group MA at 8 wk. BT also occurred in the MLNs, spleen, and kidney, which was reduced by AS supplementation. BT was not detected in the blood in any group.

CONCLUSION: Dysbiosis of gut microbiota, injury of intestinal mucosal barrier and BT occurred as liver cirrhosis progressed, which might enhance inflammation and aggravate liver injury. AS may have other non-antimalarial effects that modulate gut microbiota, inhibit BT and alleviate inflammation, resulting in a reduction in CCl₄, alcohol and high fat-caused damages to the liver and intestine.

Changes of Intestinal Functions in Liver Cirrhosis

Background

Understanding of the gut-liver axis is important for the up-to-date management of liver cirrhosis, and changes of intestinal functions form the core of this interesting research field.

Summary

Most investigators noted small intestinal dysmotility in their patients with liver cirrhosis. Marked changes in the contraction pattern were observed in early manometric studies. The orocecal transit time, particularly small intestinal transit, has generally been reported to be prolonged, which has been demonstrated in multiple investigations to be related to the severity of the liver disease (e.g., Child-Pugh class), the presence of small intestinal bacterial overgrowth (SIBO) and hepatic encephalopathy (HE) as well as a history of spontaneous bacterial peritonitis. Bacteriologically proven SIBO in proximal jejunal aspiration has been reported to be present in up to 59% of cirrhotic patients and is associated with systemic endotoxemia. Clinical and experimental studies suggest that delayed small bowel transit in liver cirrhosis may lead to SIBO, which could contribute to the symptoms of abdominal pain and diarrhea. In addition to autonomic neuropathy, metabolic derangements and diabetic state, SIBO itself may delay intestinal transit in cirrhotic patients. Several studies, both from the West and the East, have shown that the gut microbiota is altered in cirrhotic patients and particularly those with HE. Further, a quantitative change in Bacteroides/Firmicutes ratio, with a prevalence of potentially pathogenic bacteria (e.g., Enterobacteriaceae) and reduction in specific commensals (e.g., Lachnospiraceae), has been described. Structural and functional changes in the intestinal mucosa that contribute to increases in intestinal permeability for bacteria and their products have been observed in patients with liver cirrhosis, which is considered as an important pathogenetic factor for several complications. The mechanism of intestinal barrier dysfunction in cirrhosis is multifactorial, including alcohol, portal hypertension (vascular congestion and dysregulation), endotoxemia, SIBO, local inflammation and, most likely, immunological factors and medications.

Key Messages

This review summarizes major achievements regarding intestinal dysfunction in cirrhosis for future gastroenterology research. The question of whether this intestinal barrier dysfunction is accompanied and/or at least partly caused by structural and functional changes in the epithelial tight junction proteins is as yet unsolved. Development of new strategies to modulate gut-liver interaction is urgently needed.

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.

Microbiome and bacterial translocation in cirrhosis

Qualitative and quantitative changes in gut microbiota play a very important role in cirrhosis. Humans harbour around 100 quintillion gut bacteria, thus representing around 10 times more microbial cells than eukaryotic ones. The gastrointestinal tract is the largest surface area in the body and it is subject to constant exposure to these living microorganisms. The existing symbiosis, proven by the lack of proinflammatory response against commensal bacteria, implies the presence of clearly defined communication lines that contribute to the maintenance of homeostasis of the host. Therefore, alterations of gut flora seem to play a role in the pathogenesis and progress of multiple liver and gastrointestinal diseases. This has made its selective modification into an area of high therapeutic interest. Bacterial translocation is defined as the migration of bacteria or bacterial products from the intestines to the mesenteric lymph nodes. It follows that alteration in gut microbiota have shown importance, at least to some extent, in the pathogenesis of several complications arising from terminal liver disease, such as hepatic encephalopathy, portal hypertension and spontaneous bacterial peritonitis. This review sums up, firstly, how liver disease can alter the common composition of gut microbiota, and secondly, how this alteration contributes to the development of complications in cirrhosis.

Systematic review and meta-analysis of the possible association between pharmacological gastric acid suppression and spontaneous bacterial peritonitis

BACKGROUND

Observational studies have presented conflicting results with regard to an association between gastric acid suppression and spontaneous bacterial peritonitis (SBP). Our aim was to carry out a meta-analysis investigating the possible association between the use of proton pump inhibitors or H2-receptor antagonists and SBP.

METHODS

We searched several databases from inception through 15 December 2014 to identify observational studies that provided data on the association of gastric acid suppression with SBP as their primary outcome, and carried out random effects meta-analyses.

RESULTS

Fourteen observational studies (six case-control and eight cohort) evaluating the association between proton pump inhibitors and SBP revealed a pooled odds ratio (OR) of 2.32 [95% confidence interval (CI) 1.57-3.42, I(2)=82%]. The subgroup analysis based on study design revealed a pooled OR of 2.52 (95% CI 1.71-3.71, I(2)=16%) for case-control studies, and a pooled OR of 2.18 (95% CI 1.24-3.82, I(2)=89%) for cohort studies. Sensitivity analysis including only the peer-reviewed publications in the cohort subgroup revealed a pooled OR of 1.49 (95% CI 1.15-1.95, I(2)=27%). The subgroup analysis for high-quality studies revealed a pooled OR of 1.49 (95% CI 1.19-1.88, I(2)=21%). The pooled OR for H2-receptor antagonists and SBP was 1.93 (95% CI 1.15-3.24, I(2)=0%).

CONCLUSIONS

There appear to be statistically significant, but quantitatively small, associations between gastric acid suppression and SBP. However, the magnitude of the possible association diminished when analysis focused on higher quality data that were more robust. Furthermore, the quality evidence in support of the association, as per the GRADE framework, was very low.

Gut Microbiota and Host Reaction in Liver Diseases

Although alcohol feeding produces evident intestinal microbial changes in animals, only some alcoholics show evident intestinal dysbiosis, a decrease in Bacteroidetes and an increase in Proteobacteria. Gut dysbiosis is related to intestinal hyperpermeability and endotoxemia in alcoholic patients. Alcoholics further exhibit reduced numbers of the beneficial Lactobacillus and Bifidobacterium. Large amounts of endotoxins translocated from the gut strongly activate Toll-like receptor 4 in the liver and play an important role in the progression of alcoholic liver disease (ALD), especially in severe alcoholic liver injury. Gut microbiota and bacterial endotoxins are further involved in some of the mechanisms of nonalcoholic fatty liver disease (NAFLD) and its progression to nonalcoholic steatohepatitis (NASH). There is experimental evidence that a high-fat diet causes characteristic dysbiosis of NAFLD, with a decrease in Bacteroidetes and increases in Firmicutes and Proteobacteria, and gut dysbiosis itself can induce hepatic steatosis and metabolic syndrome. Clinical data support the above dysbiosis, but the details are variable. Intestinal dysbiosis and endotoxemia greatly affect the cirrhotics in relation to major complications and prognosis. Metagenomic approaches to dysbiosis may be promising for the analysis of deranged host metabolism in NASH and cirrhosis. Management of dysbiosis may become a cornerstone for the future treatment of liver diseases.

Hepatosplanchnic circulation in cirrhosis and sepsis

Hepatosplanchnic circulation receives almost half of cardiac output and is essential to physiologic homeostasis. Liver cirrhosis is estimated to affect up to 1% of populations worldwide, including 1.5% to 3.3% of intensive care unit patients. Cirrhosis leads to hepatosplanchnic circulatory abnormalities and end-organ damage. Sepsis and cirrhosis result in similar circulatory changes and resultant multi-organ dysfunction. This review provides an overview of the hepatosplanchnic circulation in the healthy state and in cirrhosis, examines the signaling pathways that may play a role in the physiology of cirrhosis, discusses the physiology common to cirrhosis and sepsis, and reviews important issues in management.

VSL#3 probiotic treatment decreases bacterial translocation in rats with carbon tetrachloride-induced cirrhosis

BACKGROUND & AIMS

Probiotics can prevent pathological bacterial translocation in cirrhosis by modulating intestinal microbiota and improving gut barrier and immune disturbances. To evaluate the effect of probiotic VSL#3 on bacterial translocation, intestinal microbiota, gut barrier and inflammatory response in rats with experimental cirrhosis.

METHODS

Forty-six Sprague-Dawley rats with CCl4 -induced cirrhosis were randomized into two groups: VSL#3 group (n = 22) that received VSL#3 in drinking water, and water group (n = 24) that received water only. Treatment began at week 6 of cirrhosis induction and continued until laparotomy, performed 1 week after development of ascites or at week 20. A control group included 11 healthy rats. At this study end, we evaluated bacterial translocation, intestinal flora, intestinal barrier (ileal claudin-2 and 4, β-defensin-1, occludin and malondialdehyde as index of oxidative damage) and serum cytokines.

RESULTS

Mortality during this study was similar in the VSL#3 group (10/22, 45%) and the water group (10/24, 42%) (P = 1). The incidence of bacterial translocation was 1/12 (8%) in the VSL#3 group, 7/14 (50%) in the water group (P = 0.03 vs. VSL#3 group) and 0/11 in the control group (P = 0.008 vs. water group). The concentration of ileal and caecal enterobacteria and enterococci was similar in the two groups of cirrhotic rats. The ileal occludin concentration was higher and ileal malondialdehyde and serum levels of TNF-α were lower in the VSL#3 group than in the water group (P < 0.05).

CONCLUSIONS

VSL#3 decreases bacterial translocation, the pro-inflammatory state and ileal oxidative damage and increases ileal occludin expression in rats with experimental cirrhosis.

The chronic use of beta-blockers and proton pump inhibitors may affect the rate of bacterial infections in cirrhosis

BACKGROUND & AIMS

Bacterial infections are among the most common and life-threatening complications in cirrhosis. Qualitative and quantitative modifications of the gut microbiota, dysfunction of the intestinal barrier and multiple immune defects are factors that contribute to a pathological 'bacterial translocation' (BT), leading to a higher susceptibility to infections in cirrhotic patients. Long-term therapies, commonly adopted in cirrhotic patients, may influence BT and modify the risk of infection in these patients. To investigate the influence of chronic therapies on the prevalence and microbiological characteristics of infections in cirrhosis.

METHODS

Consecutive cirrhotic patients hospitalised from 2008 to 2013 were enrolled. All previous treatments were carefully recorded. Infections were actively sought out, patients were actively monitored for infection, and possible risk factors were evaluated.

RESULTS

Four hundred cirrhotic patients were included. The most frequent therapies were proton pump inhibitors (PPIs) (67%), non-absorbable-disaccharides (44%), beta-blockers (BBs) (39%) and non-absorbable-antibiotics (10%). Child-Pugh C (P < 0.001; OR 5; 95%CI: 2.6-9.9) and PPI therapy (P = 0.008; OR 2; 95% CI: 1.2-3.2) were found to be independent predictors of infection, and the use of BBs was a protective factor (P = 0.001; OR 0.46; 95%CI: 0.3-0.7). Cirrhotic patients with bacterial infection showed lower morbidity and mortality when taking BBs.

CONCLUSIONS

Proton pump inhibitors increase the risk of infection in cirrhosis and should not be prescribed in these patients without specific indications. In contrast, the use of BBs is associated with a lower rate of infection and attenuates the consequences of infections in cirrhotic patients.

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.

Gastrointestinal dysfunction in liver cirrhosis

Patients with liver cirrhosis exhibit several features of gut dysfunction which may contribute to the development of cirrhosis complications as well as have an impact on nutritional status and health-related quality of life. Gastrointestinal symptoms are common in cirrhosis and their pathophysiology probably involves factors related to liver disease severity, psychological distress, and gut dysfunction (e.g., increased gastric sensitivity to distension and delayed gut transit). They may lead to reduced food intake and, thus, may contribute to the nutritional status deterioration in cirrhotic patients. Although tense ascites appears to have a negative impact on meal-induced accommodation of the stomach, published data on gastric accommodation in cirrhotics without significant ascites are not unanimous. Gastric emptying and small bowel transit have generally been shown to be prolonged. This may be related to disturbances in postprandial glucose, insulin, and ghrelin levels, which, in turn, appear to be associated to insulin resistance, a common finding in cirrhosis. Furthermore, small bowel manometry disturbances and delayed gut transit may be associated with the development of small bowel bacterial overgrowth. Finally, several studies have reported intestinal barrier dysfunction in patients with cirrhosis (especially those with portal hypertension), which is related to bacterial translocation and permeation of intestinal bacterial products, e.g., endotoxin and bacterial DNA, thus potentially being involved in the pathogenesis of complications of liver cirrhosis.

Proton pump inhibitor use significantly increases the risk of spontaneous bacterial peritonitis in 1965 patients with cirrhosis and ascites: a propensity score matched cohort study

BACKGROUND

The risk of spontaneous bacterial peritonitis (SBP) associated with proton pump inhibitor (PPI) use has been raised in cirrhotic patients with ascites. However, this is based on case-control studies, often with a small series.

AIM

To determine whether PPI use increases the risk of SBP using a large cohort.

METHODS

This retrospective cohort study included 1965 cirrhotic patients with ascites diagnosed between January 2005 and December 2009. The SBP incidence rate was compared between the PPI and non-PPI groups before and after propensity score matching to reduce the effect of selection bias and potential confounders. Multivariate analysis was conducted to confirm the association of PPI use with SBP.

RESULTS

After excluding 411 patients, 1554 were analysed. Among them, 512 patients (32.9%) were included in the PPI group. The annual SBP incidence rate was higher in the PPI group than in the non-PPI group (10.6% and 5.8%, P = 0.002) before matching. Indications for PPI use and dose of PPI were similar between patients with and without SBP. In the propensity score matched cohort (402 pairs), the SBP incidence rate was also higher in the PPI group than in the non-PPI group (10.8% vs. 6.0%, P = 0.038). Multivariate analysis revealed that PPI use (Hazard ratio 1.396; 95% confidence interval, 1.057-1.843; P = 0.019) was the independent risk factor for SBP.

CONCLUSIONS

Proton pump inhibitor use significantly increases the risk of spontaneous bacterial peritonitis in cirrhotic patients with ascites. Proton pump inhibitor use should be undertaken with greater caution and appropriately in patients with cirrhosis.

Bacterial infections in cirrhosis: a position statement based on the EASL Special Conference 2013

Bacterial infections are very common and represent one of the most important reasons of progression of liver failure, development of liver-related complications, and mortality in patients with cirrhosis. In fact, bacterial infections may be a triggering factor for the occurrence of gastrointestinal bleeding, hypervolemic hyponatremia, hepatic encephalopathy, kidney failure, and development of acute-on-chronic liver failure. Moreover, infections are a very common cause of repeated hospitalizations, impaired health-related quality of life, and increased healthcare costs in cirrhosis. Bacterial infections develop as a consequence of immune dysfunction that occurs progressively during the course of cirrhosis. In a significant proportion of patients, infections are caused by gram-negative bacteria from intestinal origin, yet gram-positive bacteria are a frequent cause of infection, particularly in hospitalized patients. In recent years, infections caused by multidrug-resistant bacteria are becoming an important clinical problem in many countries. The reduction of the negative clinical impact of infections in patients with cirrhosis may be achieved by a combination of prophylactic measures, such as administration of antibiotics, to reduce the occurrence of infections in high-risk groups together with early identification and management of infection once it has developed. Investigation on the mechanisms of altered gut microflora, translocation of bacteria, and immune dysfunction may help develop more effective and safe methods of prevention compared to those that are currently available. Moreover, research on biomarkers of early infection may be useful in early diagnosis and treatment of infections. The current manuscript reports an in-depth review and a position statement on bacterial infections in cirrhosis.

Probiotics (VSL#3) prevent endothelial dysfunction in rats with portal hypertension: role of the angiotensin system

AIMS

Portal hypertension characterized by generalized vasodilatation with endothelial dysfunction affecting nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) has been suggested to involve bacterial translocation and/or the angiotensin system. The possibility that ingestion of probiotics prevents endothelial dysfunction in rats following common bile duct ligation (CBDL) was evaluated.

METHODS

Rats received either control drinking water or the probiotic VSL#3 solution (50 billion bacteria.kg body wt⁻¹.day⁻¹) for 7 weeks. After 3 weeks, rats underwent surgery with either resection of the common bile duct or sham surgery. The reactivity of mesenteric artery rings was assessed in organ chambers, expression of proteins by immunofluorescence and Western blot analysis, oxidative stress using dihydroethidium, and plasma pro-inflammatory cytokine levels by flow cytometry.

RESULTS

Both NO- and EDH-mediated relaxations to acetylcholine were reduced in the CBDL group compared to the sham group, and associated with a reduced expression of Cx37, Cx40, Cx43, IKCa and SKCa and an increased expression of endothelial NO synthase (eNOS). In aortic sections, increased expression of NADPH oxidase subunits, angiotensin converting enzyme, AT1 receptors and angiotensin II, and formation of ROS and peroxynitrite were observed. VSL#3 prevented the deleterious effect of CBDL on EDH-mediated relaxations, vascular expression of connexins, IKCa, SKCa and eNOS, oxidative stress, and the angiotensin system. VSL#3 prevented the CBDL-induced increased plasma TNF-α, IL-1α and MCP-1 levels.

CONCLUSIONS

These findings indicate that VSL#3 ingestion prevents endothelial dysfunction in the mesenteric artery of CBDL rats, and this effect is associated with an improved vascular oxidative stress most likely by reducing bacterial translocation and the local angiotensin system.

Laboratory diagnostics of spontaneous bacterial peritonitis

The term peritonitis indicates an inflammatory process involving the peritoneum that is most frequently infectious in nature. Primary or spontaneous bacterial peritonitis (SBP) typically occurs when a bacterial infection spreads to the peritoneum across the gut wall or mesenteric lymphatics or, less frequently, from hematogenous transmission in combination with impaired immune system and in absence of an identified intra-abdominal source of infection or malignancy. The clinical presentation of SBP is variable. The condition may manifest as a relatively insidious colonization, without signs and symptoms, or may suddenly occur as a septic syndrome. Laboratory diagnostics play a pivotal role for timely and appropriate management of patients with bacterial peritonitis. It is now clearly established that polymorphonuclear leukocyte (PMN) in peritoneal fluid is the mainstay for the diagnosis, whereas the role of additional biochemical tests is rather controversial. Recent evidence also suggests that automatic cell counting in peritoneal fluid may be a reliable approach for early screening of patients. According to available clinical and laboratory data, we have developed a tentative algorithm for efficient diagnosis of SBP, which is based on a reasonable integration between optimization of human/economical resources and gradually increasing use of invasive and expensive testing. The proposed strategy entails, in sequential steps, serum procalcitonin testing, automated cell count in peritoneal fluid, manual cell count in peritoneal fluid, peritoneal fluid culture and bacterial DNA testing in peritoneal fluid.

Ascites and spontaneous bacterial peritonitis: recommendations from two United States centers

Cirrhosis affects millions of people throughout the world. Two of the most serious complications of liver cirrhosis are ascites and spontaneous bacterial peritonitis (SBP). The development of ascites is related to the severity of portal hypertension and is an indicator of increased mortality. Although sodium restriction and diuretic therapy have proven effective, some patients may not respond appropriately or develop adverse reactions to diuretic therapy. In such cases, interventions such as transjugular intrahepatic portosystemic shunt (TIPS) placement are warranted. SBP is a complication of ascites that confers a very high mortality rate. Recognition and prompt treatment of this condition is essential to prevent serious morbidity and mortality. Initiation of prophylaxis in SBP remains controversial. Given the burden of liver cirrhosis on the health care system, ascites and SBP will continue to provide challenges for the primary care provider, hospitalist, internist, and gastroenterologist alike.

Cirrhotic ascites review: Pathophysiology, diagnosis and management

Ascites is a pathologic accumulation of peritoneal fluidcommonly observed in decompensated cirrhotic states.Its causes are multi-factorial, but principally involve significant volume and hormonal dysregulation in the setting of portal hypertension. The diagnosis of ascites is considered in cirrhotic patients given a constellation of clinical and laboratory findings, and ultimately confirmed, with insight into etiology, by imaging and paracentesis procedures. Treatment for ascites is multi-modal including dietary sodium restriction, pharmacologic therapies, diagnostic and therapeutic paracentesis, and in certain cases transjugular intra-hepatic portosystemic shunt. Ascites is associated with numerous complications including spontaneous bacterial peritonitis, hepato-hydrothorax and hepatorenal syndrome. Given the complex nature of ascites and associatedcomplications, it is not surprising that it heralds increased morbidity and mortality in cirrhotic patients and increased cost-utilization upon the health-care system. This review will detail the pathophysiology of cirrhotic ascites, common complications derived from it, and pertinent treatment modalities.

Intestinal permeability and complications in liver cirrhosis: A prospective cohort study

AIM

  Increased intestinal permeability (IP) has been implicated as an important factor for bacterial translocation (BT), leading to bacteremia and endotoxemia, resulting in various septic complications, variceal bleeding (VB), hepatic encephalopathy (HE), hepatorenal syndrome (HRS) and death in patients with liver cirrhosis (LC). This study was planned to assess IP in patients with LC and follow them for the occurrence of complications.

METHODS

  Patients with Child B and C cirrhosis without a history of disease-related complications were followed up for 6 months. IP was measured by lactulose and mannitol excretion ratio (LMR) in patients and 50 healthy controls (HC). Serum endotoxin levels were also assessed in 48 patients and 20 HC.

RESULTS

  Eighty patients (74 male), 41 (51.3%) Child B and 56 (70%) Child C, with a mean age of 40.7 ± 9.8 years were enrolled. IP was increased in 28 (35%) patients. LMR of patients was higher than HC (patients vs HC = 0.0238 [0.0010-1.557] vs 0.0166 [0.0018-0.720]; P = 0.007]. No significant difference was seen in the LMR of patients among various Child classes and etiologies. Serum endotoxin levels (GMU/mL) were higher in patients than HC (patients vs HC = 1.42 [0.68-2.13] vs 0.994 [0.067-1.382]; P = 0.001), but comparable between patients with abnormal and normal IP. At follow up, there was no significant difference in the incidence of complications like spontaneous bacterial peritonitis, HRS, VB, HE and death between patients with abnormal and normal IP.

CONCLUSION

  IP was increased in 35% of patients with LC; however, it was not associated with a higher incidence of disease-related complications.