Presence of bacterial-DNA in cirrhosis identifies a subgroup of patients with marked inflammatory response not related to endotoxin

Influence of supplementation with iron and probiotic bacteria Lactobacillus plantarum and Lactobacillus curvatus on selected parameters of inflammatory state in rats on a high-fat iron-deficient diet

BACKGROUND

A high-fat (HF) diet, diet iron deficiency and iron supplementation may affect inflammatory parameters. Probiotics influence both iron metabolism and inflammation. We compared the inflammatory state in rats on a HF iron-deficient diet receiving oral iron, Lactobacillus plantarum and Lactobacillus curvatus in different combinations.

METHODS

This was a two-stage experiment. In groups C (n = 8) and HF (n = 8), rats ate a control or HF diet, respectively, for 16 weeks. In the group HFDEF (n = 48), rats ate a HF iron-deficient diet for 8 weeks (first stage) and were subsequently divided into 6 groups (n = 8 each) receiving the following for a further 8 weeks (second stage): HFDEF - a HF iron-deficient diet; HFDEFFe - a HF iron-deficient diet with iron; HFDEFLp and HFDEFLc - a HF iron-deficient diet with L. plantarum or L. curvatus, respectively; and HFDEFFeLp and HFDEFFeLc - a HF iron-deficient diet with iron and L. plantarum or L. curvatus, respectively. Body composition analysis and blood sampling was performed. Markers of iron status and levels of total antioxidant status (TAS), C-reactive protein (CRP), tumour necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were measured in the blood.

RESULTS

TAS was higher in the HFDEF group (756.57 ± 489.53 ng mL-1) versus the HFDEFLc group (187.04 ± 47.84 ng mL-1; P = 0.022). No more differences were found between groups, or in TAS, CRP, TNF-α and IL-6 concentrations. Also, no differences were found between groups for alanine and aspartate aminotransferases, glucose, total cholesterol, low- and high-density lipoproteins and triglycerides. TAS level was positively correlated with ferritin concentration, IL-6 with TAS and TNF-α with hepcidin level.

CONCLUSIONS

Supplementation with L. plantarum, L. curvatus and iron in combinations exerts no influence on inflammatory status, lipid profile, hepatic function and serum fasting glucose in rats on a HF iron-deficient diet. © 2024 Society of Chemical Industry.

Circulating neutrophil anti-pathogen dysfunction in cirrhosis

Neutrophils are the largest population of leucocytes and are among the first cells of the innate immune system to fight against intruding pathogens. In patients with cirrhosis, neutrophils exhibit altered functionality, including changes in phagocytic ability, bacterial killing, chemotaxis, degranulation, reactive oxygen species production and NET (neutrophil extracellular trap) formation. This results in their inability to mount an adequate antibacterial response and protect the individual from infection. Prognosis and survival in patients with cirrhosis are greatly influenced by the development of infectious complications. Multidrug-resistant bacterial infections in patients with cirrhosis are currently a growing problem worldwide; therefore, alternative methods for the prevention and treatment of bacterial infections in cirrhosis are urgently needed. The prevention and treatment of neutrophil dysfunction could be a potential way to protect patients from bacterial infections. However, the reasons for changes in neutrophil function in cirrhosis are still not completely understood, which limits the development of efficient therapeutic strategies. Both cellular and serum factors have been proposed to contribute to the functional impairment of neutrophils. Herein, we review the current knowledge on features and proposed causes of neutrophil dysfunction in cirrhosis, with a focus on current knowledge gaps and limitations, as well as opportunities for future investigations in this field.

Proton pump inhibitor treatment aggravates bacterial translocation in patients with advanced cirrhosis and portal hypertension

IMPORTANCE

Long-term prescription of proton pump inhibitors (PPIs) in patients with cirrhosis is common practice. However, in recent years, several observational studies have reported increased complications and negative prognostic effects of PPI treatment in these patients. Judging the significance of these associations is complicated by the fact that a plausible underlying pathomechanism has not been identified so far. In the present study, we address this important issue by investigating the impact of PPI treatment on subclinical bacterial translocation from the gut into the blood stream in patients with advanced cirrhosis and portal hypertension. Indeed, we report significantly aggravated bacterial translocation in cirrhosis patients receiving PPI treatment. This finding is highly relevant, as bacterial translocation is known to promote the development of complications and impair prognosis in patients with cirrhosis. Hence, the present study could establish a plausible link between PPI treatment and adverse effects in cirrhosis.

Influence of NOD2 risk variants on hepatic encephalopathy and association with inflammation, bacterial translocation and immune activation

BACKGROUND

Nucleotide-binding oligomerization domain containing 2 (NOD2) risk variants lead to impaired mucosal barrier function, increased bacterial translocation (BT), and systemic inflammation.

AIM

To evaluate the association between the presence of NOD2 risk variants, BT, inflammation, and hepatic encephalopathy (HE).

PATIENTS AND METHODS

This prospective multicenter study included patients with cirrhosis and testing for NOD2 risk variants (p.R702W, p.G908R, c.3020insC, N289S, and c.-958T>C). Patients were evaluated for covert (C) and overt (O) HE. Markers of systemic inflammation (leukocytes, CRP, IL-6, LBP) and immune activation (soluble CD14) as well as bacterial endotoxin (hTRL4 activation) were determined in serum.

RESULTS

Overall, 172 patients (70% men; median age 60 [IQR 54-66] years; MELD 12 [IQR 9-16]; 72% ascites) were included, of whom 53 (31%) carried a NOD2 risk variant. In this cohort, 11% presented with OHE and 27% and CHE. Presence and severity of HE and surrogates of inflammation, BT, and immune activation did not differ between patients with and without a NOD2 risk variant, also not after adjustment for MELD. HE was associated with increased ammonia and systemic inflammation, as indicated by elevated CRP (w/o HE: 7.2 [2.7-16.7]; with HE 12.6 [4.5-29.7] mg/dL; p < 0.001) and elevated soluble CD14 (w/o HE 2592 [2275-3033]; with HE 2755 [2410-3456] ng/mL; p = 0.025).

CONCLUSIONS

The presence of NOD2 risk variants in patients with cirrhosis is not associated with HE and has no marked impact on inflammation, BT, or immune activation. In contrast, the presence of HE was linked to ammonia, the acute phase response, and myeloid cell activation.

Cirrhotic Patients with Bacterial Infection and Negative Cultures Have a More Advanced Disease and an Increased Short-Term Mortality Rate

BACKGROUND

The negative clinical impact of bacterial infections (BI) in patients with cirrhosis is well documented. In cirrhotic patients, failure to isolate the pathogen is a frequent event, occurring in 30-40% of cases.

AIM

The aim of this study was to compare the clinical characteristics, early (30-day) and short-term (90-day) mortality rates, in a cohort of cirrhotic patients with BI, between those with positive (C-pos) and those with negative (C-neg) microbiological cultures.

METHODS

We retrospectively enrolled 279 consecutive hospitalized cirrhotic patients with BI. Survival and predictors of 30-day and 90-day mortality were assessed by Kaplan-Meier curves and logistic regression analysis, respectively.

RESULTS

Cultures tested negative in 108/279 (38.7%) patients. C-neg patients were more frequently males (p = 0.035), had higher Child-Pugh-Turcotte (CPT; p = 0.007) and model for end-stage liver disease-sodium (MELD-Na; p = 0.043) scores, and had more frequently decompensated liver disease (p = 0.04). Mortality rate was higher in C-neg than in C-pos patients, both at 30 days (22.2% versus 11.7%, p = 0.024) and 90 days (46.3% versus 33.3%, p = 0.030). MELD-Na score and non-selective beta-blockers (NSBBs) were independent risk factors for 30-day and 90-day mortality. In particular, the use of NSBBs was independently associated with a lower 30-day and 90-day mortality risk (OR 0.41, CI95% 0.17-0.94, p = 0.040; and OR 0.43, CI95% 0.25-0.75, p = 0.003, respectively).

CONCLUSIONS

Cirrhotic patients with BI and negative microbiological cultures have significantly higher mortality compared to those with positive cultures. Early mortality and short-term mortality are mainly influenced by the underlying severity of liver disease. In this contest, therapy with NSBBs has a positive impact on short-term survival.

Pathophysiology of decompensated cirrhosis: Portal hypertension, circulatory dysfunction, inflammation, metabolism and mitochondrial dysfunction

Patients with acutely decompensated cirrhosis have a dismal prognosis and frequently progress to acute-on-chronic liver failure, which is characterised by hepatic and extrahepatic organ failure(s). The pathomechanisms involved in decompensation and disease progression are still not well understood, and as specific disease-modifying treatments do not exist, research to identify novel therapeutic targets is of the utmost importance. This review amalgamates the latest knowledge on disease mechanisms that lead to tissue injury and extrahepatic organ failure - such as systemic inflammation, mitochondrial dysfunction, oxidative stress and metabolic changes - and marries these with the classical paradigms of acute decompensation to form a single paradigm. With this detailed breakdown of pathomechanisms, we identify areas for future research. Novel disease-modifying strategies that break the vicious cycle are urgently required to improve patient outcomes.

Gut Microbiota Changes and Their Correlation with Cognitive and Neuropsychiatric Symptoms in Alzheimer's Disease

BACKGROUND

Gut microbiota can influence human brain function and behavior. Recent studies showed that gut microbiota might play an important role in the pathogenesis of Alzheimer's disease (AD).

OBJECTIVE

To investigate the composition of gut microbiota in AD patients and their association with cognitive function and neuropsychiatric symptoms (NPS).

METHODS

The fecal samples from 60 AD patients (30 with NPS and 30 without NPS) and 32 healthy control subjects (HC) were collected and analyzed by 16S ribosomal RNA sequencing. The functional variations of gut microbiota were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States. The correlation between different bacterial taxa and cognitive (Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR)), and NPS measures were analyzed.

RESULTS

The fecal microbial composition of AD patients was quite distinct from HC. Bifidobacterium, Sphingomonas, Lactobacillus, and Blautia were enriched, while Odoribacter, Anaerobacterium, and Papillibacter were reduced. AD patients with NPS showed decreased Chitinophagaceae, Taibaiella, and Anaerobacterium compared with those without NPS. Functional pathways were different between AD and HC, and between AD patients with and without NPS. Correlation analysis showed that Sphingomonas correlated negatively with MMSE; Anaerobacterium and Papillibacter correlated positively with MMSE and negatively with CDR. Cytophagia, Rhodospirillaceae, and Cellvibrio correlated positively with NPS, while Chitinophagaceae, Taibaiella, and Anaerobacterium correlated negatively with NPS.

CONCLUSION

AD patients have gut microbiota alterations related to cognition, and differential taxa between AD patients with and without NPS associated differently with NPS domains, which helps further understand the pathogenesis of AD and explore potential therapeutic targets.

Intestinal permeability and bacterial translocation in patients with liver disease, focusing on alcoholic aetiology: methods of assessment and therapeutic intervention

Increased bacterial translocation (BT) across the gut barrier due to greater intestinal permeability (IP) is seen across a range of conditions, including alcohol-related liver disease (ArLD). The phenomenon of BT may contribute to both the pathogenesis and the development of complications in ArLD. There are a number of methods available to assess IP and in this review we look at their various advantages and limitations. The knowledge around BT and IP in ArLD is also reviewed, as well as the therapeutic strategies currently in use and in development.

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.

The Role of Gut-Derived Microbial Antigens on Liver Fibrosis Initiation and Progression

Intestinal dysbiosis has recently become known as an important driver of gastrointestinal and liver disease. It remains poorly understood, however, how gastrointestinal microbes bypass the intestinal mucosa and enter systemic circulation to enact an inflammatory immune response. In the context of chronic liver disease (CLD), insults that drive hepatic inflammation and fibrogenesis (alcohol, fat) can drastically increase intestinal permeability, hence flooding the liver with gut-derived microbiota. Consequently, this may result in exacerbated liver inflammation and fibrosis through activation of liver-resident Kupffer and stellate cells by bacterial, viral, and fungal antigens transported to the liver via the portal vein. This review summarizes the current understanding of microbial translocation in CLD, the cell-specific hepatic response to intestinal antigens, and how this drives the development and progression of hepatic inflammation and fibrosis. Further, we reviewed current and future therapies targeting intestinal permeability and the associated, potentially harmful anti-microbial immune response with respect to their potential in terms of limiting the development and progression of liver fibrosis and end-stage cirrhosis.

Compartmentalization of Immune Response and Microbial Translocation in Decompensated Cirrhosis

Background: Acquired dysfunctional immunity in cirrhosis predisposes patients to frequent bacterial infections, especially spontaneous bacterial peritonitis (SBP), leading to systemic inflammation that is associated with poor outcome. But systemic inflammation can also be found in the absence of a confirmed infection. Detection of bacterial DNA has been investigated as a marker of SBP and as a predictor of prognosis. Data is, however, contradictory. Here we investigated whether levels of IL-6 and IL-8 putatively produced by myeloid cells in ascites are associated with systemic inflammation and whether inflammation depends on the presence of specific bacterial DNA. Methods and Materials: We enrolled 33 patients with decompensated liver cirrhosis from whom we collected paired samples of blood and ascites. IL-6 and IL-8 were measured in serum samples of all patients using ELISA. In a subset of 10 representative patients, bacterial DNA was extracted from ascites and whole blood, followed by 16S rRNA gene amplicon sequencing. Results: There were significantly higher levels of IL-6 in ascites fluid compared to blood samples in all patients. Interestingly, IL-6 levels in blood correlated tightly with disease severity and surrogates of systemic inflammation, while IL-6 levels in ascites did not. Moreover, patients with higher blood CRP levels showed greater SBP prevalence compared to patients with lower levels, despite similar positive culture results. Bacterial richness was also significantly higher in ascites compared to the corresponding patient blood. We identified differences in microbial composition and diversity between ascites and blood, but no tight relationship with surrogates of systemic inflammation could be observed. Discussion: In decompensated cirrhosis, markers of systemic inflammation and microbiota composition seem to be dysregulated in ascites and blood. While a relationship between systemic inflammation and microbiota composition seems to exist in blood, this is not the case for ascites in our hands. These data may suggest compartmentalization of the immune response and interaction of the latter with the microbiota especially in the blood compartment.

Bacterial DNA translocation contributes to systemic inflammation and to minor changes in the clinical outcome of liver transplantation

Bacterial (bact)DNA is an immunogenic product that frequently translocates into the blood in cirrhosis. We evaluated bactDNA clearance in patients undergoing liver transplantation (LT) and its association with inflammation and clinically relevant complications. We prospectively included patients consecutively admitted for LT in a one-year follow-up study. We evaluated bactDNA before and during the first month after LT, quantifying cytokine response at 30 days. One hundred patients were included. BactDNA was present in the blood of twenty-six patients undergoing LT. Twenty-four of these showed bactDNA in the portal vein, matching peripheral blood-identified bactDNA in 18 cases. Thirty-four patients showed bactDNA in blood during the first month after LT. Median TNF-α and IL-6 levels one month after LT were significantly increased in patients with versus without bactDNA. Serum TNF-α at baseline was an independent risk factor for bactDNA translocation during the first month after LT in the multivariate analysis (Odds ratio (OR) 1.14 [1.04 to 1.29], P = 0.015). One-year readmission was independently associated with the presence of bactDNA during the first month after LT (Hazard ratio (HR) 2.75 [1.39 to 5.45], P = 0.004). The presence of bactDNA in the blood of LT recipients was not shown to have any impact on complications such as death, graft rejection, bacterial or CMV infections. The rate of bactDNA translocation persists during the first month after LT and contributes to sustained inflammation. This is associated with an increased rate of readmissions in the one-year clinical outcome after LT.

Treatment with non-selective beta-blockers affects the systemic inflammatory response to bacterial DNA in patients with cirrhosis

BACKGROUND & AIMS

The use of non-selective beta-blockers has been associated with lower rates of infection and reduced infection-associated morbidity in patients with cirrhosis. However, it is unknown if these drugs modify the systemic inflammatory response to circulating bacterial DNA.

METHODS

Sixty-three patients with cirrhosis were included during an episode of decompensation by ascites. Thirty of those patients were on beta-blockers. Blood samples were obtained after each patient had been in the supine position for at least 30 minutes in a quiet atmosphere. Bacterial DNA, serum cytokines, nitric oxide, and LPS were determined. Phagocytic and oxidative burst activities were determined in polymorphonuclear cells from the patients.

RESULTS

The detection rate of bacterial DNA in the blood was the same (33%) for patients not treated and treated with non-selective beta-blockers. Patients naive to non-selective beta-blockers showed significantly higher serum levels of IL6, IFN-gamma and IL10 in response to the presence of bacterial DNA. Patients treated with non-selective beta-blockers showed higher basal inflammatory activity that did not change with the presence of bacterial DNA. Monocytes and granulocytes from patients treated with non-selective beta-blockers showed a significantly increased phagocytic capacity in the presence of bacterial DNA.

CONCLUSIONS

In patients with cirrhosis, chronic treatment with beta-blockers is associated with a higher unstimulated production of serum cytokines and an increased phagocytic activity in the presence of bacterial DNA.

Effects of bacterial translocation on hemodynamic and coagulation parameters during living-donor liver transplant

BACKGROUND

Bacterial translocation (BT) has been proposed as a trigger for stimulation of the immune system with consequent hemodynamic alteration in patients with liver cirrhosis. However, no information is available regarding its hemodynamic and coagulation consequences during liver transplantation.

METHODS

We screened 30 consecutive adult patients undergoing living-donor liver transplant for the presence of BT. Bacterial DNA, Anti factor Xa (aFXa), thromboelastometry, tumor necrosis factor-α TNF-α, and interleukin-17 (IL-17) values were measured in sera before induction of anesthesia. Systemic hemodynamic data were recorded throughout the procedures.

RESULTS

Bacterial DNA was detected in 10 patients (33%) (bactDNA(+)). Demographic, clinical, and hemodynamic data were similar in patients with presence or absence of bacterial DNA. BactDNA(+) patients showed significantly higher circulating values of TNF-α and IL-17, and had significantly higher clotting times and clot formation times as well as significantly lower alpha angle and maximal clot firmness than bactDNA(-) patients, P < 0.05. We found no statistically significant difference in aFXa between the groups, P = 0.4. Additionally, 4 patients in each group needed vasopressor agents, P = 0.2. And, the amount of transfused blood and blood products used were similar between both groups.

CONCLUSION

Bacterial translocation was found in one-third of patients at the time of transplantation and was largely associated with increased markers of inflammation along with decreased activity of coagulation factors.

TRIAL REGISTRATION

Trial Registration Number: NCT03230214 . (Retrospective registered). Initial registration date was 20/7/2017.

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

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

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.

Toll-like receptor polymorphisms compromise the inflammatory response against bacterial antigen translocation in cirrhosis

Bacterial translocation is associated with clinically relevant complications in cirrhosis. We evaluated the effect of toll-like receptor polymorphisms in the soluble response against these episodes. Consecutive patients with cirrhosis and ascitic fluid were distributed by TLR2 rs4696480, TLR4 rs4986790, and TLR9 rs187084 single-nucleotide polymorphisms. Lipoteichoic acid, lipopolyssaccharide, bacterial-DNA, pro-inflammatory cytokines and nitric oxide levels were quantified in serum samples. In vitro response against specific ligands in variant TLR genotypes was evaluated. One hundred and fourteen patients were included. Variant TLR-2, TLR-4 and TLR-9 SNP genotypes were associated with significantly increased serum levels of LTA, LPS and bacterial-DNA. TNF-α, IL-6 and nitric oxide serum levels were significantly decreased in all variant TLR genotyped patients. Cytokine levels were significantly less upregulated in response to specific TLR-ligands in patients with all variant vs wildtype TLR genotypes. Although in vitro gene expression levels of all wildtype and variant TLRs were similar, MyD88 and NFkB were significantly downregulated in cells from TLR-variant genotyped patients in response to their ligands. Variant TLR genotypes are associated with an increased circulating antigen burden and a decreased proinflammatory response in cirrhosis. This immunodeficiency may facilitate bacteria-related complications in cirrhosis and enhance TLR targeting for its management.

Terlipressin Improves Renal Function and Reverses Hepatorenal Syndrome in Patients With Systemic Inflammatory Response Syndrome

BACKGROUND & AIMS

Patients with systemic inflammatory response syndrome (SIRS) along with decompensated cirrhosis and renal dysfunction have a poor prognosis and a lower response to treatment. We evaluated the effect of SIRS on the response of hepatorenal syndrome type 1 (HRS-1) to terlipressin.

METHODS

We performed a retrospective study of data from a trial of the effects of terlipressin (1 mg every 6 hours or placebo with concomitant albumin) in 198 patients with HRS-1, performed at 50 investigational sites in the United States and 2 in Canada from October 2010 through February 2013. We identified patients with 2 or more criteria for SIRS, without untreated infections (28 received terlipressin and 30 received placebo), and patients with less than 2 criteria for SIRS (control subjects). Primary endpoints included HRS reversal (a decrease in serum level of creatinine to ≤1.5 mg/dL), confirmed HRS reversal (defined as 2 serum creatinine levels ≤1.5 mg/dL, ≥ 48 hours apart), and survival for 90 days after treatment.

RESULTS

Baseline characteristics were similar between groups, apart from slightly higher white blood cell counts and heart rates, and slightly lower serum levels of bicarbonate in patients with SIRS versus without SIRS. HRS was reversed in 42.9% of patients who received terlipressin with SIRS (12/28) versus 6.7% of patients who received placebo (2/30) (P = .0018); confirmed HRS reversal occurred in 32.1% of patients who received terlipressin with SIRS (9/28) versus 3.3% who received placebo (1/30) (P = .0048). A larger proportion of patients with SIRS who received terlipressin survived for 90 days without a transplant (13/28; 46.4%) than patients with SIRS who received placebo (7/30; 23.3%) (P = .076).

CONCLUSIONS

In an analysis of data from a placebo-controlled study, we found that terlipressin improved renal function and reversed HRS in a higher proportion of patients with HRS-1 and SIRS than patients who received albumin plus placebo. ClincialTrials.gov, number NCT 01143246.

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).

The digestive tract as the origin of systemic inflammation

Failure of gut homeostasis is an important factor in the pathogenesis and progression of systemic inflammation, which can culminate in multiple organ failure and fatality. Pathogenic events in critically ill patients include mesenteric hypoperfusion, dysregulation of gut motility, and failure of the gut barrier with resultant translocation of luminal substrates. This is followed by the exacerbation of local and systemic immune responses. All these events can contribute to pathogenic crosstalk between the gut, circulating cells, and other organs like the liver, pancreas, and lungs. Here we review recent insights into the identity of the cellular and biochemical players from the gut that have key roles in the pathogenic turn of events in these organ systems that derange the systemic inflammatory homeostasis. In particular, we discuss the dangers from within the gastrointestinal tract, including metabolic products from the liver (bile acids), digestive enzymes produced by the pancreas, and inflammatory components of the mesenteric lymph.

The prognostic significance of bacterial DNA in patients with decompensated cirrhosis and suspected infection

BACKGROUND & AIMS

Circulating and peritoneal fragments of microbial DNA (bactDNA) are evidence for bacterial translocation in decompensated cirrhosis and may serve as a rational approach for antibiotic therapy when infection is suspected.

METHODS

Prospective multicenter study to investigate whether identification of bactDNA from blood or ascitic fluid (AF) by multiplex polymerase chain reaction (PCR) is associated with increased 90-day mortality in 218 patients with cirrhosis and signs of infection.

RESULTS

BactDNA in either compartment was detected in 134 (61%) patients, comprising 54 with bactDNA in blood and AF, 48 with AF bactDNA only, and 32 with blood bactDNA only. BactDNA was associated with spontaneous bacterial peritonitis and blood stream infections (SBP/BSI), acute-on-chronic liver failure (ACLF), encephalopathy and markers of inflammation. The prevalence of bactDNA in patients with proven SBP/BSI (36/49; 73%) was similar to that in patients with sterile ACLF (37/52; 71%). Actuarial 90-day survival was 56 ± 5% in the absence of bactDNA in both compartments and did not differ if bactDNA was detected in blood only (63 ± 9%), AF only (63 ± 7%), or in blood and AF (52 ± 7%). Predictors of 90-day mortality were SBP (HR = 3.10; 95% CI: 1.90-5.06), BSI (HR = 4.94; 95% CI: 2.71-9.02), and ACLF (HR = 2.20; 95% CI: 1.44-3.35). The detection of resistance genes in blood or AF in the absence of SBP/BSI (n = 11) was associated with poor 1-year survival (HR = 2.35; 95% CI: 1.03-5.35).

CONCLUSIONS

BactDNA in sterile body fluids did not indicate increased mortality in cirrhotic patients with suspected infection. Using multiplex PCR for risk stratification cannot be recommended in these patients.

Inflammasome activation in decompensated liver cirrhosis

Inflammation participates in the pathogenesis of many liver diseases, including liver cirrhosis. Certain inflammatory citokines, such as interleukin (IL)-1β and IL-18, are produced after the activation of a multiprotein complex known as the inflammasome. Activation of the inflammasome has been documented in several liver diseases, but its role in the development and progression of liver cirrhosis or the complications associated with this disease is still largely unknown. We have recently studied the impact of the inflammasome in the sterile inflammatory response that takes place in the ascitic fluid of patients with decompensated cirrhosis, providing evidence that activation of the absent in melanoma 2 (AIM2) inflammasome is an important response in these patients. Ascitic fluid-derived macrophages were able to mount a very robust AIM2-mediated response even in the absence of a priming signal, which is usually required for the full activation of all the inflammasomes. In addition, high level of inflammasome activation in these patients was associated with a higher degree of liver disease and an increased incidence of spontaneous bacterial peritonitis. These results may help explain the exacerbated inflammatory response that usually occurs in patients with decompensated cirrhosis in the absence of detectable infections. Thus, inflammasomes should be considered as possible therapeutic targets in sterile inflammatory complications in patients with cirrhosis.

Gut microbiota in health and disease: an overview focused on metabolic inflammation

In concern to the continuously rising global prevalence of obesity, diabetes and associated diseases, novel preventive and therapeutic approaches are urgently required. However, to explore and develop such innovative strategies, a meticulous comprehension of the biological basis of these diseases is extremely important. Past decade has witnessed an enormous amount of research investigation and advancement in the field of obesity, diabetes and metabolic syndrome, with the gut microbiota receiving a special focus in the triangle of nutrition, health and diseases. In particular, the role of gut microbiota in health and diseases has been one of the most vigorous and intriguing field of recent research; however, much still remains to be elucidated about its precise role in host metabolism and immune functions and its implication in the onset, progression as well as in the amelioration of metabolic ailments. Recent investigations have suggested a significant contribution of the gut microbiota in the regulation and impairment of energy homeostasis, thereby causing metabolic disorders, such as metabolic endotoxemia, insulin resistance and type 2 diabetes. Numerous inflammatory biomarkers have been found to be associated with obesity, diabetes and risk of other associated adverse outcomes, thereby suggesting that a persistent low-grade inflammatory response is a potential risk factor. In this milieu, this review intends to discuss potential evidences supporting the disturbance of the gut microbiota balance and the intestinal barrier permeability as a potential triggering factor for systemic inflammation in the onset and progression of obesity, type 2 diabetes and metabolic syndrome.

Markers of bacterial translocation in end-stage liver disease

Bacterial translocation (BT) refers to the passage of viable bacteria or bacterial products from the intestinal lumen, through the intestinal epithelium, into the systemic circulation and extraintestinal locations. The three principal mechanisms that are thought to be involved in BT include bacterial overgrowth, disruption of the gut mucosal barrier and an impaired host defence. BT is commonly observed in liver cirrhosis and has been shown to play an important role in the pathogenesis of the complications of end stage liver disease, including infections as well as hepatic encephalopathy and hepatorenal syndrome. Due to the importance of BT in the natural history of cirrhosis, there is intense interest for the discovery of biomarkers of BT. To date, several such candidates have been proposed, which include bacterial DNA, soluble CD14, lipopolysaccharides endotoxin, lipopolysaccharide-binding protein, calprotectin and procalcitonin. Studies on the association of these markers with BT have demonstrated not only promising data but, oftentimes, contradictory results. As a consequence, currently, there is no optimal marker that may be used in clinical practice as a surrogate for the presence of BT.

Absent in melanoma 2 triggers a heightened inflammasome response in ascitic fluid macrophages of patients with cirrhosis

BACKGROUND & AIMS

Inflammation is a common event in the pathogenesis of liver cirrhosis. The inflammasome pathway has acquired significant relevance in the pathogenesis of inflammation, but its role in the inflammatory response in patients with decompensated cirrhosis remains unexplored.

METHODS

We performed a prospective study in which 44 patients with decompensated cirrhosis and 12 healthy volunteers were included. We isolated macrophages from blood and ascitic fluid and assessed the expression and activation of the inflammasome, its response to priming by bacterial products, and its association with the degree of liver disease.

RESULTS

Macrophages from sterile ascitic fluids showed constitutive activation of caspase-1 and a marked increase in the expression of IL-1β, IL-18, and absent in melanoma 2 (AIM2) when compared to blood macrophages. Pre-stimulation of blood-derived macrophages from cirrhotic patients with bacterial DNA increased the expression of AIM2 and induced a higher AIM2-mediated inflammasome response than priming with other bacterial products such as lipopolysaccharide. By contrast, activation of the AIM2 inflammasome did not require a priming signal in ascitic fluid-derived macrophages, demonstrating the preactivated state of the inflammasome in these cells. Last, higher IL-1β and IL-18 production by ascitic fluid macrophages correlated with a more advanced Child-Pugh score.

CONCLUSIONS

The inflammasome is highly activated in the ascitic fluid of cirrhotic patients, which may explain the exacerbated inflammatory response observed in these patients under non-infected conditions. Clinically, activation of the inflammasome is associated with a higher degree of liver disease.

Association of markers of bacterial translocation with immune activation in decompensated cirrhosis

BACKGROUND

Bacterial translocation (BT) may cause infections, in particular, spontaneous bacterial peritonitis (SBP). In the absence of overt infection, BT may further stimulate the immune system and contribute to haemodynamic alterations and complications. Bacterial DNA (bDNA) is claimed to be a promising surrogate marker for BT, although its clinical relevance has been questioned.

MATERIALS AND METHODS

In 38 cirrhotic patients with and without SBP, bDNA in blood and ascites were assessed by 16S rDNA quantitative PCR. Levels of lipopolysaccharide-binding protein in plasma and highly sensitive C-reactive protein, tumour necrosis factor-α, soluble urokinase plasminogen activating receptor, interleukin-6, interleukin 8, interferon-γ inducible protein-10 and vascular endothelial growth factor in plasma and ascites were measured by multiplex cytokine and ELISA assays.

RESULTS

In patients without signs of SBP or positive cultures, we found a high frequency of bDNA but low concordance of bDNA between blood and ascites. Markers of inflammation were not significantly different between blood bDNA-positive (22%), ascites bDNA-positive (52%), and bDNA-negative patients. The 16S rDNA PCR failed to show bDNA in two out of six samples with SBP. Sequencing of positive samples did not determine the source of bDNA.

CONCLUSION

bDNA as assessed by this PCR method was largely unrelated to markers of inflammation and does not seem to be of clinical value in the diagnosis of SBP. According to our results, bDNA is not a reliable marker of BT.

Cirrhosis-associated immune dysfunction: distinctive features and clinical relevance

The term cirrhosis-associated immune dysfunction refers to the main syndromic abnormalities of immune function, immunodeficiency and systemic inflammation that are present in cirrhosis. The course of advanced cirrhosis, regardless of its aetiology, is complicated by cirrhosis-associated immune dysfunction and this constitutes the pathophysiological hallmark of an increased susceptibility to bacterial infection, distinctive of the disease. Cirrhosis impairs the homeostatic role of the liver in the systemic immune response. Damage to the reticulo-endothelial system compromises the immune surveillance function of the organ and the reduced hepatic synthesis of proteins, involved in innate immunity and pattern recognition, hinders the bactericidal ability of phagocytic cells. Systemic inflammation, in form of activated circulating immune cells and increased serum levels of pro-inflammatory cytokines, is the result of persistent episodic activation of circulating immune cells from damage-associated molecular patterns, released from necrotic liver cells and, as cirrhosis progresses, from pathogen-associated molecular patterns, released from the leaky gut. Cirrhosis-associated immune dysfunction phenotypes switch from predominantly "pro-inflammatory" to predominantly "immunodeficient" in patients with stable ascitic cirrhosis and in patients with severely decompensated cirrhosis and extra-hepatic organ failure (e.g. acute-on-chronic liver failure), respectively. These cirrhosis-associated immune dysfunction phenotypes represent the extremes of a spectrum of reversible dynamic events that take place during the course of cirrhosis. Systemic inflammation can affect the functions of tissue somatic cells and modify the clinical manifestation of cirrhosis. The best characterized example is the contribution of systemic inflammation to the haemodynamic derangement of cirrhosis, which correlates negatively with prognosis.

Impairment of innate immune responses in cirrhotic patients and treatment by branched-chain amino acids

It has been reported that host defense responses, such as phagocytic function of neutrophils and natural killer (NK) cell activity of lymphocytes, are impaired in cirrhotic patients. This review will concentrate on the impairment of innate immune responses in decompensated cirrhotic patients and the effect of the treatment by branched-chain amino acids (BCAA) on innate immune responses. We already reported that phagocytic function of neutrophils was significantly improved by 3-mo BCAA supplementation. In addition, the changes of NK activity were also significant at 3 mo of supplementation compared with before supplementation. Also, Fisher’s ratios were reported to be significantly increased at 3 mo of BCAA supplementation compared with those before oral supplementation. Therefore, administration of BCAA could reduce the risk of bacterial and viral infection in patients with decompensated cirrhosis by restoring impaired innate immune responses of the host. In addition, it was also revealed that BCAA oral supplementation could reduce the risk of development of hepatocellular carcinoma in cirrhotic patients. The mechanisms of the effects will also be discussed in this review article.

Ascitic Fluid Analysis in the Differential Diagnosis of Ascites: Focus on Cirrhotic Ascites

Ascites is the pathologic accumulation of fluid within the peritoneal cavity. Because many diseases can cause ascites, in particular cirrhosis, samples of ascitic fluid are commonly analyzed in order to develop a differential diagnosis. The concept of transudate versus exudate, as determined by total protein measurements, is outdated and the use of serum-ascites albumin gradient as an indicator of portal hypertension is more accurate. Lactate dehydrogenase (LDH), vascular endothelial growth factor (VEGF), and other tumor markers can be helpful in distinguishing between malignant and benign conditions. Glucose and adenosine deaminase levels may support a diagnosis of tuberculous disease, and amylase level may indicate a diagnosis of pancreatitis. Given the specificity and sensitivity of laboratory results, accurate diagnosis should be based on both laboratory data and clinical judgment.

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.

Attenuated antigen-specific T cell responses in cirrhosis are accompanied by elevated serum interleukin-10 levels and down-regulation of HLA-DR on monocytes

BACKGROUND

Advanced liver disease predisposes to bacterial translocation and endotoxaemia which can contribute to elevated circulating levels of IL-10 and down-regulation of MHC class II on antigen-presenting cells. We sought to evaluate antigen-specific T-cell responses toward common viral antigens in order to investigate defects in cellular immunity in cirrhosis.

METHODS

Peripheral blood was obtained from 22 cirrhotic patients with systemic inflammation, 13 cirrhotic patients without systemic inflammation and 14 healthy controls. C-reactive protein was used as an indicator for systemic inflammation using a cut-off of 10 mg/l. Intracellular Th1 cytokines were quantified after T cell-stimulation with the viral peptides EBNA1 and BZLF1 or the bacterial superantigen SEB by flow cytometry. Serum levels of lipopolysaccharide-binding protein (LBP) and IL-10 were quantified by ELISA.

RESULTS

Compared to healthy controls, patients with cirrhosis had higher circulating levels of LBP and IL-10, an expansion of peripheral blood CD14+ monocytes with low HLA-DR expression and an increased fraction of CD25-positive CD4+ and CD8+ T cells. These findings were most pronounced in cirrhotic patients with systemic inflammation but fell short of reaching statistical significance when comparing against cirrhotic patients without systemic inflammation. In the former group TNF-α production in CD4+ and CD8+ T cells was reduced after stimulation with SEB, whereas there was no significant difference between the total cohort of cirrhotic patients and controls. After stimulation with the overlapping peptide pools for viral antigens EBNA1 and BZLF1, the number of responding T cells and the amount of TNF-α or IFN-γ production did not differ between the three pre-defined groups. However, cirrhotic patients with null-responses to EBV peptides had significantly higher serum IL-10 levels than responders to EBV peptides. Furthermore, TNF-α production in responding T cells was attenuated in patients with a high frequency of CD14+ HLA-DR- monocytes.

CONCLUSION

Our data suggest that bacterial translocation, endotoxaemia, inflammation and T cell activation in cirrhosis are accompanied by an increase in circulating anti-inflammatory cytokines, reduced monocytic MHC class II expression and attenuated cytokine production in T cells. These changes are likely to contribute to altered adaptive immune responses during infection or after vaccination.

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.

Leaky gut and the liver: A role for bacterial translocation in nonalcoholic steatohepatitis

Gut flora and bacterial translocation (BT) play important roles in the pathogenesis of chronic liver disease, including cirrhosis and its complications. Intestinal bacterial overgrowth and increased bacterial translocation of gut flora from the intestinal lumen predispose patients to bacterial infections, major complications and also play a role in the pathogenesis of chronic liver disorders. Levels of bacterial lipopolysaccharide, a component of gram-negative bacteria, are increased in the portal and/or systemic circulation in several types of chronic liver disease. Impaired gut epithelial integrity due to alterations in tight junction proteins may be the pathological mechanism underlying bacterial translocation. Preclinical and clinical studies over the last decade have suggested a role for BT in the pathogenesis of nonalcoholic steatohepatitis (NASH). Bacterial overgrowth, immune dysfunction, alteration of the luminal factors, and altered intestinal permeability are all involved in the pathogenesis of NASH and its complications. A better understanding of the cell-specific recognition and intracellular signaling events involved in sensing gut-derived microbes will help in the development of means to achieve an optimal balance in the gut-liver axis and ameliorate liver diseases. These may suggest new targets for potential therapeutic interventions for the treatment of NASH. Here, we review some of the mechanisms connecting BT and NASH and potential therapeutic developments.

Detection of ascitic fluid infections in patients with liver cirrhosis and ascites

BACKGROUND AND STUDY AIMS

Ascitic fluid infections (AFIs) are the frequent complications of advanced liver disease. Bacterial translocation is considered a key step in the pathogenesis of gut-derived bacterial infections; mainly spontaneous bacterial peritonitis (SBP) in cirrhotic patients. Bacterial DNA (bactDNA) in ascitic fluid and serum has been suggested as a surrogate marker for bacterial translocation. We attempted at the isolation and identification of bacteria in ascitic fluid in cirrhotic patients and the assessment of polymerase chain reaction (PCR) in ascitic fluid and serum.

PATIENTS AND METHODS

Fifty cirrhotic patients having ascites with no signs of infection were included. Ascitic fluid cultures were obtained from patients. Ascitic fluid and serum were subjected to DNA extraction and PCR for the universal amplification of a region of the 16S ribosomal RNA (16S rRNA) gene to detect bactDNA.

RESULTS

Bacteria were isolated from 9 (18%) of the ascitic fluid samples, and were mainly Gram-positive bacteria. BactDNA was detected simultaneously in the ascitic fluid and serum of 17 (34%) patients and in the ascitic fluid of only 2 patients. In a single patient with positive ascitic fluid culture no bactDNA was detected in ascitic fluid or serum. By considering AFIs as a positive ascitic fluid culture and/or the presence of bactDNA in the ascitic fluid and/or serum, ascitic fluid culture could detect 9 out of 20 patients with AFIs (45%), PCR of ascitic fluid could detect 19 out of 20 (95%) while PCR of serum could detect 17 out of 20 (85%). In 10 patients with culture negative non-neutrocytic ascites (CNNNA) bactDNA could be detected in serum and ascitic fluid.

CONCLUSION

AFI can be caused by Gram positive as well as Gram negative organisms. A substantial percentage of cases with CNNNA show bactDNA in serum and ascitic fluid. PCR of ascitic fluid should, therefore, be used in the diagnostic workup of suspected cases of ascitic fluid infections.

Gut microbiota and inflammation

Systemic and local inflammation in relation to the resident microbiota of the human gastro-intestinal (GI) tract and administration of probiotics are the main themes of the present review. The dominating taxa of the human GI tract and their potential for aggravating or suppressing inflammation are described. The review focuses on human trials with probiotics and does not include in vitro studies and animal experimental models. The applications of probiotics considered are systemic immune-modulation, the metabolic syndrome, liver injury, inflammatory bowel disease, colorectal cancer and radiation-induced enteritis. When the major genomic differences between different types of probiotics are taken into account, it is to be expected that the human body can respond differently to the different species and strains of probiotics. This fact is often neglected in discussions of the outcome of clinical trials with probiotics.

Prevalence of spontaneous bacterial peritonitis in asymptomatic inpatients with decompensated liver cirrhosis - a pilot study

PURPOSE

To assess the prevalence of spontaneous bacterial peritonitis (SBP) in asymptomatic patients with decompensated liver cirrhosis.

MATERIAL AND METHODS

Patients (pts) with symptoms of decompensation of liver cirrhosis, ascites, and no signs indicating SBP were included to our study. Exclusion criteria include: 1/ clinical symptoms of infection, 2/ developing de novo or worsening hepatic encephalopathy, 3/ gastrointestinal bleeding within the last month, 4/ renal failure, 5/ antibiotic treatment or norfloxacin prophylaxis at admission. About 60 ml of ascitic fluid were drawn for lab examination. Pathologic assessment for atypical cells was also performed.

RESULTS

37 patients fulfilled inclusion criteria. Their mean age was 56.2 ± 12.1. The Child-Pugh classification revealed 13 (35.1%) patients of class B and 24 (64.9%) patients of class C. The mean Model for End-Stage Liver Disease score in this group was 16.6 ± 6.8. The mean ascitic protein content was 1.85 ± 1.09 g/dL and mean neutrophil count 144.8 ± 445.1/mm3. Ascitic fluid analysis revealed: signs of bacterascites in 6 of 37 (16.2%) pts; neutrocytic ascites in 1 of 37 (2.7%) pts; and 2 of 37 (5.4%) pts met criteria for SBP. C-reactive protein level was the best predictor of infection [SBP(+) 47.9 ± 40.9 versus SBP(-) 11.7 ± 5.1; p= 0.0005].

CONCLUSIONS

The prevalence of SBP in asymptomatic cirrhotics with ascites is low. We observed the trend towards more frequent occurrence of the infection in patients suffered from severe liver disease (Child-Pugh C group).

Interleukin-10-mediated heme oxygenase 1-induced underlying mechanism in inflammatory down-regulation by norfloxacin in cirrhosis

Patients with cirrhosis receiving norfloxacin show a restored inflammatory balance that likely prevents clinical complications derived from an excessive proinflammatory response to bacterial product challenges. This study sought to investigate associated inflammatory control mechanisms established in patients with cirrhosis receiving norfloxacin. A total of 62 patients with cirrhosis and ascites in different clinical conditions were considered. Blood samples were collected and intracellular and serum norfloxacin were measured. Inflammatory mediators were evaluated at messenger RNA and protein levels. Neutrophils from all patients were cultured with lipopolysaccharide (LPS) and anti-interleukin-10 (anti-IL-10) monoclonal antibody in different conditions. IL-10 and heme oxygenase-1 (HO-1) were up-regulated in patients receiving norfloxacin and correlated with norfloxacin in a concentration-dependent manner, whereas proinflammatory inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor-κB behaved inversely. Higher IL-10 levels correlated with lower white blood cell count and higher mean arterial pressure. No correlations were found between IL-10 and disease clinical scores or liver function markers in blood. Neutrophilic in vitro assays showed that the effect of LPS on proinflammatory mediator levels in the presence of norfloxacin was abrogated by significantly increasing IL-10 and HO-1 expression. After stimulation with LPS plus anti-IL-10, proinflammatory mediators were dramatically increased in patients receiving norfloxacin, and increasing intracellular norfloxacin concentrations did not decrease the expression levels of these proinflammatory molecules. Unblocking IL-10 restored proinflammatory mediator and HO-1 expression to previously observed levels in response to LPS stimulation.

CONCLUSION

Although the described association does not necessarily mean causality, an IL-10-mediated HO-1-induced anti-inflammatory mechanism is present in patients with cirrhosis receiving norfloxacin, that is directly associated with cell-modulating events in these patients.

Bacterial DNA in the diagnosis of spontaneous bacterial peritonitis

BACKGROUND

Despite inoculation into blood culture bottles, ascitic fluid culture is negative in 50% of cases of spontaneous bacterial peritonitis (SBP).

AIM

To determine whether 16S rDNA gene detection by real-time polymerase chain reaction (PCR) and sequencing increases the efficacy of culture in microbiological diagnosis of spontaneous bacterial peritonitis.

METHODS

We prospectively included 55 consecutive spontaneous bacterial peritonitis episodes in cirrhotic patients, 20 cirrhotic patients with sterile ascites and 27 patients with neoplasic ascites. Ascitic fluid was inoculated into blood culture bottles at the bedside and tested for bacterial DNA by real-time PCR and sequencing of 16S rDNA gene.

RESULTS

Bacterial DNA was detected in 23/25 (92%) culture-positive SBP, 16/30 (53%) culture-negative SBP (P = 0.002 with respect to culture-positive SBP), 12/20 (60%) sterile ascites (P = 0.01 with respect to culture-positive SBP) and 0/27 neoplasic ascites (P < 0.001 with respect to other groups). Sequencing identified to genus or species level 12 culture-positive SBP, six culture-negative SBP and six sterile ascites. In the remaining cases with positive PCR, sequencing did not yield a definitive bacterial identification.

CONCLUSIONS

Bacterial DNA was not detected in almost half the culture-negative spontaneous bacterial peritonitis episodes. Methodology used in the present study did not always allow identification of amplified bacterial DNA.

Critical role of the liver in the induction of systemic inflammation in rats with preascitic cirrhosis

Systemic activation of the inflammatory immune system contributes to the progression of cirrhosis with ascites. Immune cells become activated after interacting at the mesenteric lymph nodes (MLNs) with bacteria translocated from the gut, and thereafter reach the bloodstream through recirculation. It is unknown whether systemic activation of the immune system is present in pre-ascitic cirrhosis, in which gut bacterial translocation has not been described. The purpose of this study was to determine whether systemic activation of the immune system initiates in rats with compensated carbon tetrachloride (CCl(4))-induced cirrhosis, and if so to establish the activation site of immune cells. We studied the activation status of immune cells in peripheral blood, MLNs, and hepatic lymph nodes (HLNs). Systemic inflammation was present in rats with cirrhosis, as shown by expansion (P < 0.01) of circulating total and inflammatory monocytes and recently activated CD134(+) T helper (T(h)) cells. The same populations of cells were increased (P < 0.01) in MLNs and HLNs. Bacterial translocation was absent in rats with cirrhosis or control rats, but bacterial DNA fragments were present in the MLNs of 54% of rats with cirrhosis. The liver was the source of activated immune cells present in the blood, as shown by the direct correlation between activated T(h) cells in the blood and HLNs, but not in MLNs, and the normalization by gut decontamination with antibiotics of activated cells in MLNs, but not in the blood or HLNs.

CONCLUSION

In experimental cirrhosis, systemic activation of the immune system occurs before ascites development and is driven by recirculation of cells activated in HLNs. In addition, in compensated cirrhosis, bacterial DNA fragments reach the MLNs, where they elicit a local inflammatory response.

Bacterial DNA translocation is associated with systemic circulatory abnormalities and intrahepatic endothelial dysfunction in patients with cirrhosis

Presence of bacterial DNA in noninfected patients with cirrhosis and ascites is associated with a marked inflammatory response including activation of the inducible form of nitric oxide synthase and release of nitric oxide, similar to that observed in patients with spontaneous bacterial peritonitis. Although presence of bacterial DNA is associated with an impaired prognosis, no information is available regarding its hemodynamic consequences. Systemic and hepatic hemodynamics before and after a liquid test meal were assessed in a series of 75 noninfected patients with cirrhosis (55 with ascites). Bacterial DNA was measured by polymerase chain reaction. Bacterial DNA was detected only in patients with ascites. Clinical data and liver function were similar in ascitic patients with presence (n = 21) or absence of bacterial DNA (n = 34). Bacterial-DNA(+) patients had significantly lower mean arterial pressure (P = 0.002) and systemic vascular resistance (P = 0.03) than bacterial-DNA(-) patients. Cardiac output, cardiopulmonary pressures, hepatic venous pressure gradient (HVPG), and hepatic blood flow were similar in both groups. Thirty minutes after the test meal, in response to increased blood flow caused by postprandial hyperemia, there was a significantly greater increase in HVPG and impaired hepatic vasorelaxation in bacterial-DNA(+) as compared with bacterial-DNA(-) patients, which indicates hepatic endothelial dysfunction. Indeed, the increase in HVPG after the test meal significantly correlated with serum bacterial DNA concentration.

CONCLUSION

Presence of bacterial DNA, a marker of bacterial translocation, is associated with aggravation of peripheral vasodilation and with worsening of intrahepatic endothelial dysfunction.

Identification of bacterial DNA in neutrocytic and non-neutrocytic cirrhotic ascites by means of a multiplex polymerase chain reaction

BACKGROUND

Even though bacterial cultures of ascitic fluid are negative in up to 65% of the cases of spontaneous bacterial peritonitis (SBP); bacterial DNA (bactDNA) has been frequently detected in episodes of SBP as well as in culture-negative non-neutrocytic ascites.

AIMS

To evaluate multiplex polymerase chain reaction (PCR) for pathogen identification in SBP and to determine the prevalence of ascitic bactDNA and its prognostic relevance in hospitalized patients with liver cirrhosis.

METHODS

Ascitic fluid from 68 consecutive patients who underwent diagnostic paracentesis was analysed for polymorphonuclear leucocyte (PMN) count, bacterial culture and bactDNA. BactDNA was identified by gel analysis after multiplex PCR of selectively enriched prokaryotic nucleic acids. Correlations of bactDNA status with PMN count, bacterial culture result and 3-month mortality were determined for neutrocytic and for non-neutrocytic ascites.

RESULTS

11/68 patients presented with an elevated ascitic PMN count. BactDNA was detected in 5/5 culture-positive neutrocytic samples, in 1/6 culture-negative neutrocytic samples and in 8/56 culture-negative non-neutrocytic samples. Three-month mortality did not differ with respect to ascitic bactDNA status (7/14 vs. 14/47, P=0.162). 3-month mortality was increased in the presence of ascitic bactDNA for patients older than 65 years (4/5 vs. 4/14, P=0.046) and for patients with a model for end-stage liver disease score >15 (7/10 vs. 9/30, P=0.025).

CONCLUSIONS

Identification of ascitic bactDNA is an appropriate alternative to bacterial ascite culture for pathogen identification in patients at risk for SBP. Its prognostic relevance as a proposed marker of bacterial translocation for certain risk groups has to be further evaluated.