Ascites bacterial burden and immune cell profile are associated with poor clinical outcomes in the absence of overt infection

Studies on the Role of Compartmentalized Profiles of Cytokines in the Risk of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the most common form of liver cancer, is frequently diagnosed late due to the absence of symptoms during early disease, thus heavily affecting the overall survival of these patients. Soluble immunological factors persistently produced during cirrhosis have been recognized as promoters of chronic inflammation and neoplastic transformation. The aim of this pilot study was to evaluate the predictive value of the cytokine profiles for HCC development. A Luminex xMAP approach was used for the quantification of 45 proteins in plasma and ascitic fluids of 44 cirrhotic patients without or with HCC of different etiologies. The association with patient survival was also evaluated. Univariate analyses revealed that very low levels of interleukin 5 (IL-5) (<15.86 pg/mL) in ascites and IL-15 (<12.40 pg/mL) in plasma were able to predict HCC onset with an accuracy of 81.8% and a sensitivity of 95.2%. Univariate analyses also showed that HCC, hepatitis B virus/hepatitis C virus infections, low levels of IL-5 and granulocyte-macrophage colony-stimulating factor in ascitic fluids, and high levels of eotaxin-1, hepatocyte growth factor and stromal-cell-derived factor 1α in plasma samples were factors potentially associated with a poor prognosis and decreased survival. Our results suggest a potential protective role of some immune modulators that may act in the peritoneal cavity to counteract disease progression leading to HCC development.

Alterations of gut microbiota in cirrhotic patients with spontaneous bacterial peritonitis: A distinctive diagnostic feature

Background

Spontaneous bacterial peritonitis (SBP) is a severe infection in cirrhotic patients that requires early diagnosis to improve the long-term outcome. Alterations in the gut microbiota have been shown to correlate with the development and progression of liver cirrhosis. However, the relationship between SBP and gut microbiota remains unknown.

Methods

In this study, we applied 16S rRNA pyrosequencing of feces to ascertain possible links between the gut microbiota and SBP. We recruited 30 SBP patients, 30 decompensated cirrhotic patients without SBP (NSBP) and 30 healthy controls. Metagenomic functional prediction of bacterial taxa was achieved using PICRUSt.

Results

The composition of the gut microbiota in the SBP patients differed remarkably from that in the NSBP patients and healthy individuals. The microbial richness was significantly decreased, while the diversity was increased in the SBP patients. Thirty-four bacterial taxa containing 15 species, mainly pathogens such as Klebsiella pneumoniae, Serratia marcescens and Prevotella oris, were dominant in the SBP group, while 42 bacterial taxa containing 16 species, especially beneficial species such as Faecalibacterium prausnitzii, Methanobrevibacter smithii and Lactobacillus reuteri, were enriched in the NSBP group. Notably, we found that 18 gene functions of gut microbiota were different between SBP patients and NSBP patients, which were associated with energy metabolism and functional substance metabolism. Five optimal microbial markers were determined using a random forest model, and the combination of Lactobacillus reuteri, Rothia mucilaginosa, Serratia marcescens, Ruminococcus callidus and Neisseria mucosa achieved an area under the curve (AUC) value of 0.8383 to distinguish SBP from decompensated cirrhosis.

Conclusions

We described the obvious dysbiosis of gut microbiota in SBP patients and demonstrated the potential of microbial markers as noninvasive diagnostic tools for SBP at an early stage.

Interactive effects of fluoride and seleno-l-methionine at environmental related concentrations on zebrafish (Danio rerio) liver via the gut-liver axis

Fluoride (F) is a ubiquitous aquatic environmental pollutant and co-exists with other pollutants to form combined pollution. Selenium (Se) is beneficial at low levels yet toxic at high levels and can interact with some metals. However, the interactive effects of F and Se on the liver in fish remains enigmatic. In this study, zebrafish (Danio rerio) were exposed to F (80 mg/L) and dietary seleno-l-methionine (Se-Met, 0.25, 0.5 and 1.0 μg/g dry weight) alone or in combination for 90 d. The results indicated that co-treatment to F and Se-Met attenuated the histopathological damage, oxidative stress, and inflammatory in the liver, compared with the F treatment alone. Meanwhile, dietary Se-Met treatment improved F-induced intestinal barrier dysfunction, increased the transcripts of tight junction proteins (ZO-1, Claudin-1 and Occludin), and restored the homeostasis of intestinal microbiota. Moreover, dietary Se-Met ameliorated F-induced intestinal and liver inflammation by inhibiting lipopolysaccharide (LPS) levels and transcripts of TLR4 and p65 in the intestine and liver. This study manifested that Se-Met alleviates F-induced liver and intestinal injury when both co-occur at specific concentrations, and that the gut-liver axis pathway may serve as a mechanistic base for these alleviative effects.

Plasticity of monocytes and macrophages in cirrhosis of the liver

Cirrhosis of the liver is a systemic condition with raising prevalence worldwide. Patients with cirrhosis are highly susceptible to develop bacterial infections leading to acute decompensation and acute-on-chronic liver failure both associated with a high morbidity and mortality and sparse therapeutic options other than transplantation. Mononuclear phagocytes play a central role in innate immune responses and represent a first line of defence against pathogens. Their function includes phagocytosis, killing of bacteria, antigen presentation, cytokine production as well as recruitment and activation of immune effector cells. Liver injury and development of cirrhosis induces activation of liver resident Kupffer cells and recruitment of monocytes to the liver. Damage- and pathogen-associated molecular patterns promote systemic inflammation which involves multiple compartments besides the liver, such as the circulation, gut, peritoneal cavity and others. The function of circulating monocytes and tissue macrophages is severely impaired and worsens along with cirrhosis progression. The underlying mechanisms are complex and incompletely understood. Recent 'omics' technologies help to transform our understanding of cellular diversity and function in health and disease. In this review we point out the current state of knowledge on phenotypical and functional changes of monocytes and macrophages during cirrhosis evolution in different compartments and their role in disease progression. We also discuss the value of potential prognostic markers for cirrhosis-associated immuneparesis, and future immunotherapeutic strategies that may reduce the need for transplantation and death.

Recent insights into the characteristics and role of peritoneal macrophages from ascites of cirrhotic patients

Macrophages are a diverse myeloid cell population involved in innate and adaptive immune responses, embryonic development, wound repair, and regulation of tissue homeostasis. These cells link the innate and adaptive immunities and are crucial in the development and sustainment of various inflammatory diseases. Macrophages are tissue-resident cells in steady-state conditions; however, they are also recruited from blood monocytes after local pathogen invasion or tissue injury. Peritoneal macrophages vary based on their cell complexity, phenotype, and functional capabilities. These cells regulate inflammation and control bacterial infections in the ascites of decompensated cirrhotic patients. Our recent work reported several phenotypic and functional characteristics of these cells under both healthy and pathological conditions. A direct association between cell size, CD14/CD16 expression, intracellular level of GATA-6, and expression of CD206 and HLA-DR activation/maturation markers, indicate that the large peritoneal macrophage CD14^highCD16^high subset constitutes the mature phenotype of human resident peritoneal macrophages during homeostasis. Moreover, elevated expression of CD14/CD16 is related to the phagocytic capacity. The novel large CD14^highCD16^high peritoneal subpopulation is increased in the ascites of cirrhotic patients and is highly sensitive to lipopolysaccharide (LPS)-induced activation, thereby exhibiting features of inflammatory priming. Thus, phosphorylation of ERK1/2, PKB/Akt, and c-Jun is remarkably increased in response to LPS in vitro, whereas that of p38 MAPK is reduced compared with the monocyte-derived macrophages from the blood of healthy controls. Furthermore, in vitro activated monocyte-derived macrophages from ascites of cirrhotic patients secreted significantly higher levels of IL-6, IL-10, and TNF-α and lower amounts of IL-1β and IL-12 than the corresponding cells from healthy donor’s blood. Based on these results, other authors have recently reported that the surface expression level of CD206 can be used to identify mature, resident, inflammatory peritoneal macrophages in patients with cirrhosis. Soluble CD206 is released from activated large peritoneal macrophages, and increased concentrations in patients with cirrhosis and spontaneous bacterial peritonitis (SBP) indicate reduced odds of survival for 90 d. Hence, the level of soluble CD206 in ascites might be used to identify patients with SBP at risk of death. In conclusion, peritoneal macrophages present in ascites of cirrhotic patients display multiple phenotypic modifications characterized by reduced ratio of cells expressing several membrane markers, together with an increase in the ratios of complex and intermediate subpopulations and a decrease in the classic-like subset. These modifications may lead to the identification of novel pharmaceutical targets for prevention and treatment of hepatic damage.

Bacteriophages immunomodulate the response of monocytes

Bacteriophages are present in fluids from cirrhosis patients. However, their effect on the immune response is unknown. In this work, we explore the role of phages in the phenotype, function, and cytokine production of monocytes. We stimulated healthy monocytes with five different butanol-purified phage suspensions infective for Gram-negative and Gram-positive bacteria. We studied the expression of the monocyte markers involved in lipopolysaccharide recognition (LPS; CD14), antigen presentation (HLA-DR) and co-stimulation (CD86), and the concentration of induced cytokines (TNF-α, IFN-α, and IL-10) by phages. To confirm the direct role of phages without the interference of contaminating soluble LPS in phage suspensions, polymyxin B was added to the cell cultures. Phagocytosis experiments were assessed by flow cytometry using labeled phage suspensions. We observed that butanol-purified phages reduced the surface levels of CD14 and CD86 in monocytes and increased the secreted levels of TNF-α and IL-10 compared with the control sample containing only butanol buffer. All phage suspensions showed downregulation of HLA-DR expression but only Staphylococcus aureus phage contaminated with Escherichia coli reached statistical significance. The addition of polymyxin B did not restore the monocytic response induced by phages, suggesting that the effect was not caused by the presence of LPS. Monocytes were able to phagocyte phages in a dose- and time-dependent manner. To conclude, the phagocytosis of butanol-purified phages altered the phenotype and cytokine production of monocytes suggesting they become tolerogenic.

Macrophages in Chronic Liver Failure: Diversity, Plasticity and Therapeutic Targeting

Chronic liver injury results in immune-driven progressive fibrosis, with risk of cirrhosis development and impact on morbidity and mortality. Persistent liver cell damage and death causes immune cell activation and inflammation. Patients with advanced cirrhosis additionally experience pathological bacterial translocation, exposure to microbial products and chronic engagement of the immune system. Bacterial infections have a high incidence in cirrhosis, with spontaneous bacterial peritonitis being the most common, while the subsequent systemic inflammation, organ failure and immune dysregulation increase the mortality risk. Tissue-resident and recruited macrophages play a central part in the development of inflammation and fibrosis progression. In the liver, adipose tissue, peritoneum and intestines, diverse macrophage populations exhibit great phenotypic and functional plasticity determined by their ontogeny, epigenetic programming and local microenvironment. These changes can, at different times, promote or ameliorate disease states and therefore represent potential targets for macrophage-directed therapies. In this review, we discuss the evidence for macrophage phenotypic and functional alterations in tissue compartments during the development and progression of chronic liver failure in different aetiologies and highlight the potential of macrophage modulation as a therapeutic strategy for liver disease.

Risk of ambulatory colonoscopy in patients with cirrhosis: a propensity-score matched cohort study

Background and study aims  Patients with cirrhosis demonstrate alterations in physiology, hemodynamics, and immunity which may increase procedural risk. There exist sparse data regarding the safety of performing ambulatory colonoscopy in patients with cirrhosis. Patients and methods  From a population-based sample of three North American states (California, Florida, and New York), we collected data on 3,590 patients with cirrhosis who underwent ambulatory colonoscopy from 2009 to 2014. We created a control cohort propensity score-matched for cirrhotic severity who did not undergo colonoscopy (N = 3,590) in order to calculate the attributable risk for adverse events. The primary endpoint was the rate of unplanned hospital encounters (UHEs) within 14 days of colonoscopy (or from a synthetic index date for the control cohort). Predictors for UHE were assessed in multivariable regression. Results  The attributable risk for any UHE following colonoscopy was 3.1 % (confidence interval [CI] 2.1-4.1 %, P  < 0.001). There was increased risk for infection (0.9 %, CI 0.7-1.1 %), spontaneous bacterial peritonitis (0.1 %, CI 0.0-0.3 %), decompensation of ascites (0.3 %, CI 0.2-0.4 %), and cardiovascular event (0.4 %, CI 0.3-0.5 %). There was no increased attributable risk for gastrointestinal bleeding, perforation, or development of the hepatorenal syndrome. The presence of ascites at time of procedure was the only predictor for UHE in the fully-adjusted model (OR 2.6, CI 1.9-3.5, P  < 0.001). Conclusions  There is a moderate though detectable increase in risk for adverse event following ambulatory colonoscopy in patients with cirrhosis. The presence of ascites in particular portends higher risk. These data may guide clinicians when counseling patients with cirrhosis on the choice of colorectal cancer screening modality.

Human amniotic stem cells improve hepatic microvascular dysfunction and portal hypertension in cirrhotic rats

BACKGROUND AND AIMS

Portal hypertension is the main consequence of cirrhosis, responsible for the complications defining clinical decompensation. The only cure for decompensated cirrhosis is liver transplantation, but it is a limited resource and opens the possibility of regenerative therapy. We investigated the potential of primary human amniotic membrane-derived mesenchymal stromal (hAMSCs) and epithelial (hAECs) stem cells for the treatment of portal hypertension and decompensated cirrhosis.

METHODS

In vitro: Primary liver sinusoidal endothelial cells (LSECs) and hepatic stellate cells (HSCs) from cirrhotic rats (chronic CCl₄ inhalation) were co-cultured with hAMSCs, hAECs or vehicle for 24 hours, and their RNA profile was analysed. In vivo: CCl₄-cirrhotic rats received 4x10⁶ hAMSCs, 4x10⁶ hAECs, or vehicle (NaCl 0.9%) (intraperitoneal). At 2-weeks we analysed: a) portal pressure (PP) and hepatic microvascular function; b) LSECs and HSCs phenotype; c) hepatic fibrosis and inflammation.

RESULTS

In vitro experiments revealed sinusoidal cell phenotype amelioration when co-cultured with stem cells. Cirrhotic rats receiving stem cells, particularly hAMSCs, had significantly lower PP than vehicle-treated animals, together with improved liver microcirculatory function. This hemodynamic amelioration was associated with improvement in LSECs capillarization and HSCs de-activation, though hepatic collagen was not reduced. Rats that received amnion derived stem cells had markedly reduced hepatic inflammation and oxidative stress. Finally, liver function tests significantly improved in rats receiving hAMSCs.

CONCLUSIONS

This preclinical study shows that infusion of human amniotic stem cells effectively decreases PP by ameliorating liver microcirculation, suggesting that it may represent a new treatment option for advanced cirrhosis with portal hypertension.

NK Cells in Ascites From Liver Disease Patients Display a Particular Phenotype and Take Part in Antibacterial Immune Response

Background and Aims: Ascites and spontaneous bacterial peritonitis (SBP) are frequent complications of liver cirrhosis. In spite of the clinical impact, knowledge about ascites as an immune cell compartment in liver disease is limited. Therefore, we analyzed NK cells in blood, ascites, and liver. Methods: Mononuclear cells from blood, ascites, and liver explants of patients with advanced liver disease were extracted by density gradient centrifugation. Phenotyping and analysis of functional responses were carried out using flow cytometry. Migratory potential was investigated with transwell chamber assays. NK cell metabolism was assessed by Seahorse technology. Results: NK cell frequency was increased in uninfected ascites compared to blood, but not to liver. Ascites NK cells were predominantly CD16positive. CD56bright ascites NK cells did not share the typical phenotype of their liver counterparts. In contrast to the inhibitory receptor NKG2A, expression of the activating receptor NKG2D was decreased on ascites and liver CD16positive NK cells. Ascites NK cells expressed higher levels of CXCR3 than blood or liver NK cells, corresponding to increased ascites levels of CXCL10. Blood NK cells migrated toward ascites. Stimulation of mononuclear cells with Escherichia coli led to downregulation of NKG2D expression and IL-12 and IL-18 mediated secretion of interferon-γ by ascites and liver, but not blood NK cells. In-vivo, ascites NK cells expressed higher levels of the activation marker CD69 and lower levels of NKG2D during SBP compared to uninfected ascites. Conclusion: Ascites NK cells display a particular phenotype and are implicated in local immune defense against translocating bacteria.

Serum CD64 and ascitic fluid calprotectin and microRNA-155 as potential biomarkers of spontaneous bacterial peritonitis

AIM

Patients with ascites are at a higher risk for associated of on top bacterial infections with subsequent life-threatening complications. We aimed to evaluate CD64, calprotectin, and microRNA-155 (miR-155) levels as diagnostic markers of spontaneous bacterial peritonitis (SBP) and the effect of using more than one use on the same spot over their diagnostic efficiency.

PATIENTS AND METHODS

An observational comparative study included 103 patients with ascites admitted to the Tropical Medicine Department, Mansoura University Hospital, Egypt, divided into two groups: case group (64 patients) with ascites with SBP and control group (39 patients) with decompensated cirrhotic non-SBP ascites. Twenty milliliters of ascetic fluid was obtained from all participants for bacterial culture, and assessment of calprotectin and miR-155, in addition to 2 ml blood for the CD64 marker expression assay by a flowcytometer.

RESULTS

The sensitivity and specificity of CD64 expression assay were 95.3 and 92.3%, respectively, area under the curve (AUC)=0.93, whereas those of ascetic fluid calprotectin and miR-155 were 87.5 and 82.1%, AUC=0.90 and 95.3 and 97.4%, with AUC of 0.95. Combined blood CD64 and ascetic fluid calprotectin had a diagnostic accuracy of 0.988 for blood CD64 and ascetic fluid miR-155, AUC=0.991, and that for ascetic fluid calprotectin and miR-155 was 0.988. On using the three studied markers together, the diagnostic accuracy was the best recorded, AUC=0.994. P values were less than 0.001.

CONCLUSION

CD64, calprotectin, and miR-155 were good diagnostic markers of SBP and on using this combination, greater efficiency in diagnosis was achieved.

Role of ascitic prostaglandin E2 in diagnosis of spontaneous bacterial peritonitis and prediction of in-hospital mortality in patients with decompensated cirrhosis

Spontaneous bacterial peritonitis (SBP) is one of the most frequent and severe complications in patients with decompensated cirrhosis. Early antibiotic therapy is extremely important for successful treatment and reducing mortality. Prostaglandin E2 (PGE2) is a regulator of the immune response and infection. This study aimed to explore whether ascitic PGE2 could be used as a marker for diagnosing SBP and predicting in-hospital mortality.Patients with cirrhosis and ascites undergoing abdominal paracentesis were enrolled in our study. Demographic, clinical, and laboratory parameters were recorded at the time of paracentesis and ascitic PGE2 levels were determined by ELISA. The correlation between ascitic PGE2 level and SBP as well as in-hospital mortality were analyzed.There were 224 patients enrolled, 29 (13%) patients diagnosed as SBP based on the current guideline criteria. The ascitic PGE2 level of patients with SBP [32.77 (26.5-39.68) pg/mL] was significantly lower than that of patients without SBP [49.72 (37.35-54.72) pg/mL]. In ROC analysis, the AUC of ascitic PGE2 for the diagnosis of SBP was 0.75, and the AUC of ascitic PGE2 combined with WBC and ascitic PGE2 combined with neutrophils were 0.90 and 0.90, respectively, which were significantly higher than that of ascitic PGE2. In multivariate analysis, ascites PGE2≤32.88 pg/mL (OR: 9.39; 95% CI: 1.41-67.44, P = .026), hepatic encephalopathy (OR: 18.39; 95% CI: 3.00-113.13, P = .002) and a higher MELD score (OR: 1.25; 95% CI: 1.05-1.40, P = .009) remained independent predictors of in-hospital mortality.Ascitic PGE2 level is likely to be a valuable marker in prediction of in-hospital mortality in patients with decompensated cirrhosis, and its value in diagnosis of SBP was not superior to other inflammatory indicators.

Causes and Consequences of Innate Immune Dysfunction in Cirrhosis

Liver cirrhosis is an increasing health burden and public health concern. Regardless of etiology, patients with cirrhosis are at risk of a range of life-threatening complications, including the development of infections, which are associated with high morbidity and mortality and frequent hospital admissions. The term Cirrhosis-Associated Immune Dysfunction (CAID) refers to a dynamic spectrum of immunological perturbations that develop in patients with cirrhosis, which are intimately linked to the underlying liver disease, and negatively correlated with prognosis. At the two extremes of the CAID spectrum are systemic inflammation, which can exacerbate clinical manifestations of cirrhosis such as hemodynamic derangement and kidney injury; and immunodeficiency, which contributes to the high rate of infection in patients with decompensated cirrhosis. Innate immune cells, in particular monocytes/macrophages and neutrophils, are pivotal effector and target cells in CAID. This review focuses on the pathophysiological mechanisms leading to impaired innate immune function in cirrhosis. Knowledge of the phenotypic manifestation and pathophysiological mechanisms of cirrhosis associated immunosuppression may lead to immune targeted therapies to reduce susceptibility to infection in patients with cirrhosis, and better biomarkers for risk stratification, and assessment of efficacy of novel immunotherapies.

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.

Ascitic Bacterial Composition Is Associated With Clinical Outcomes in Cirrhotic Patients With Culture-Negative and Non-neutrocytic Ascites

Ascites bacterial burden is associated with poor clinical outcomes in patients with end-stage liver disease. However, the impact of ascitic microbial composition on clinical course was still not clear. In this study, the ascitic microbiota composition of 100 cirrhotic patients with culture-negative and non-neutrocytic ascites were researched with 16S rRNA pyrosequencing and enterotype-like cluster analysis. Results: By characterizing the ascitic microbial composition, two distinct microbial clusters were observed, Cluster 1 (86 patients) and Cluster 2 (14 patients). Cluster 1 showed lower microbial richness than Cluster 2. At the phylum level, Cluster 1 had greater abundance of Bacteroidetes and Firmicutes, but less abundance of Proteobacteria and Actinobacteria than Cluster 2. At the family level, family Bacteroidales S24-7 group, Prevotellaceae, Lachnospiraceae, Lactobacillaceae, Rikenellaceae, and Vibrionaceae were found over-represented in Cluster 1. And family Acetobacteraceae, Erysipelotrichaceae, Rickettsiaceae, and Streptococcaceae were found enriched in Cluster 2. The levels of plasma cytokine IL-17A, IL-7, and PDGF-BB were found significantly higher in Cluster 1 than in Cluster 2. There were four OTUs closely correlated with plasma cytokines, which were OTU 140 and OTU 271 (both from Bacteroidales S24-7 group), OTU 68 (Veillonellaceae), and OTU 53 (Helicobacteraceae). Patients from Cluster 1 showed significant higher short-term mortality than patients from Cluster 2. Conclusion: Our study demonstrated that the microbial composition of culture-negative and non-neutrocytic ascites in cirrhotic patients is associated with short-term clinical outcomes. The results here offer a rational for the identification of patients with high risk, and provide references for selective use of prophylactic methods.

Amplification of bacterial genomic DNA from all ascitic fluids with a highly sensitive polymerase chain reaction

Due to varying positive rates of polymerase chain reaction (PCR) amplification, interpretation of conventional PCR results for non‑infectious ascites remains problematic. The present study developed a highly sensitive PCR protocol and investigated the positive rate of PCR for the 16S ribosomal (r)RNA gene in non‑infectious ascites. Following the design of a new PCR primer pair for the 16S rRNA gene (800F and 1400R), the sequences of PCR products were analyzed and the lower limit for bacterial DNA detection evaluated. The positive rate of PCR for 16S rRNA gene in non‑infectious ascites was also evaluated. PCR with the primer pair amplified the genomic DNA of 16S rRNA genes of major disease‑causing bacterial strains. Additionally, PCR with this primer pair provided highly sensitive detection of bacterial genomic DNA (lower limit, 0.1 pg of template DNA). When DNA samples isolated from ascites were used, the 16S rRNA gene was amplified independently of the presence of bacterial infection. PCR products contained the genomic DNA fragments of multiple bacterial species. Bacterial genomic DNA can be amplified from all ascitic fluids using a highly sensitive PCR protocol. Careful attention is required to interpret the results based on simple amplification of 16S rRNA gene with conventional PCR.

Bacterial translocation in patients with liver cirrhosis: physiology, clinical consequences, and practical implications

The gut liver axis is an operative unit that works to protect the human body against potentially harmful substances and microorganisms, maintaining the homeostasis of the immune system. Liver cirrhosis profoundly alters this complex system. The intestine becomes more permeable allowing the translocation of bacteria, bacterial products and fragments into the portal circulation, triggering an abnormal local and systemic inflammatory response and a condition of perpetual immunologic alarm. This immune-inflammatory disorder related to dysbiosis is involved in the development of liver damage and liver cirrhosis complications and increases intestinal permeability in a vicious circle. Areas covered: The most relevant studies on bacterial translocation, the mechanism of intestinal barrier dysfunction and its consequences in patients with liver cirrhosis have been revised through a PubMed search. Data have been discussed with particular regard to their significance in clinical practice. Expert commentary: The assessment of bacterial translocation and intestinal permeability is not currently used in clinical practice but may be useful to stratify patients' prognosis.

Relative Ascites Polymorphonuclear Cell Count Indicates Bacterascites and Risk of Spontaneous Bacterial Peritonitis

BACKGROUND AND AIMS

Absolute polymorphonuclear (PMN) counts in ascites define spontaneous bacterial peritonitis (SBP), a severe form of bacterial infection in liver cirrhosis. Bacterascites, another form of ascites infection, can progress to SBP or may resolve spontaneously but is not reflected by absolute PMN counts. We investigated whether the relative ascites PMN count (the absolute PMN count divided by the absolute leukocyte count) provides additional information to detect bacterascites or predict SBP.

METHODS

Hospitalized patients with liver cirrhosis requiring paracentesis were stratified with respect to a diagnosis of bacterascites and SBP with a prospective follow-up for 1 year. Diagnostic power of relative PMN counts in ascites was evaluated by receiver operating characteristics curves.

RESULTS

At inclusion, we observed 28/269 (10%) and 43/269 (16%) episodes of BA and SBP, respectively. Unlike absolute PMN counts, relative PMN counts in ascites were significantly elevated in bacterascites (p = 0.001). During follow-up, 16 and 30 further episodes of BA and SBP were detected, respectively. Relative PMN counts increased significantly once patients developed BA (p = 0.001). At a threshold of 0.20 for the relative PMN count, sensitivity, specificity, positive and negative predictive values for bacterascites which required antibiotic treatment were 83, 75, 26 and 98%, respectively (p < 0.001). Furthermore, a relative PMN count in ascites ≥0.13 and MELD score >17 was independent factors associated with occurrence of SBP during follow-up.

CONCLUSION

The relative PMN count is a cheap immunological marker linked to bacterascites and future SBP, which may help to stratify patients according to their risk of infection.

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.

MicroRNA-155 is upregulated in ascites in patients with spontaneous bacterial peritonitis

MircoRNA’s (miR) have been recognised as important modulators of gene expression and potential biomarkers. However, they have been rarely investigated in bio fluids apart from blood. We investigated the association of miR-125b and miR-155 with complications of cirrhosis. Ascites was prospectively collected from patients with cirrhosis undergoing paracentesis at our department. miR’s were determined in the supernatant using qPCR and normalized by SV-40. Clinical parameters were assessed at paracentesis and during follow-up. 76 specimens from 72 patients were analysed. MiR’s were not associated to age, sex or aetiology of cirrhosis. MiR-125b levels differed between patients with low and high MELD score, and miR-125b levels showed an inverse correlation to serum creatinine (r² = −0.23; p = 0.05). MiR-155 was elevated in patients with spontaneous bacterial peritonitis (SBP) (n = 10; p = 0.04). MiR-155 levels differed between patients with and without 30-day survival (p = 0.02). No association of ascites levels of investigated miR’s to size of varices, episodes of gastrointestinal bleeding or hepatorenal syndrome was observed. While miR-125b levels in ascites seem to be associated with liver and renal dysfunction, miR-155 might be implicated in local immune response in SBP.

Detection of molecular bacterascites in decompensated cirrhosis defines a risk with decreased survival

BACKGROUND

The prognostic relevance of bacterial DNA (bactDNA) detection in ascitic fluid of patients with cirrhosis is still under debate. Using quantitative real-time PCR with broad-range primers targeting the V3 and V4 variable region of the 16S rRNA gene, we measured bactDNA concentrations in patients with and without leukocytic ascites and evaluated the impact on short-term survival.

PATIENTS AND METHODS

Ascites samples from 173 patients with decompensated cirrhosis were consecutively collected between February 2011 and December 2012. BactDNA-positive ascites samples were sequenced and chromatograms were identified using RipSeq. Clinical data collection and survival analyses were carried out retrospectively and correlated with ascites bactDNA levels.

RESULTS

BactDNA was detected qualitatively with a similar frequency in both nonleukocytic and leukocytic ascites [40% (57/144) and 43.5% (10/23), respectively; P=0.724]. However, the median bactDNA level was significantly higher in leukocytic ascites than in nonleukocytic ascites (1.2×10 vs. 5.7×10 copies/ml; P=0.008). Patients' survival was associated significantly with bactDNA level. The 30-day and 180-day survival was reduced if bactDNA was above the quantification limit of 520 copies/ml (84 and 63% vs. 72 and 43%, respectively; P<0.05) and worst if bactDNA was above 5000 copies/ml. The bacterial spectrum was dominated by Gram-positive strains as shown by direct sequencing.

CONCLUSION

BactDNA quantification in ascitic fluid samples using culture-independent 16S rRNA gene-based methods seems to be an interesting approach to identify patients at risk of reduced survival. Our study warrants further evaluation of antibiotic treatment in patients with molecular bacterascites.

CRIg-expressing peritoneal macrophages are associated with disease severity in patients with cirrhosis and ascites

Infections are an important cause of morbidity and mortality in patients with decompensated cirrhosis and ascites. Hypothesizing that innate immune dysfunction contributes to susceptibility to infection, we assessed ascitic fluid macrophage phenotype and function. The expression of complement receptor of the immunoglobulin superfamily (CRIg) and CCR2 defined two phenotypically and functionally distinct peritoneal macrophage subpopulations. The proportion of CRIg^hi macrophages differed between patients and in the same patient over time, and a high proportion of CRIg^hi macrophages was associated with reduced disease severity (model for end-stage liver disease) score. As compared with CRIg^lo macrophages, CRIg^hi macrophages were highly phagocytic and displayed enhanced antimicrobial effector activity. Transcriptional profiling by RNA sequencing and comparison with human macrophage and murine peritoneal macrophage expression signatures highlighted similarities among CRIg^hi cells, human macrophages, and mouse F4/80^hi resident peritoneal macrophages and among CRIg^lo macrophages, human monocytes, and mouse F4/80^lo monocyte-derived peritoneal macrophages. These data suggest that CRIg^hi and CRIg^lo macrophages may represent a tissue-resident population and a monocyte-derived population, respectively. In conclusion, ascites fluid macrophage subset distribution and phagocytic capacity is highly variable among patients with chronic liver disease. Regulating the numbers and/or functions of these macrophage populations could provide therapeutic opportunities in cirrhotic patients.

Systemic levels of human β-defensin 1 are elevated in patients with cirrhosis

BACKGROUND

Bacterial translocation (BT) commonly occurs in cirrhosis. Reliable biomarkers for BT are currently lacking. Human beta defensin-1 (hBD-1) is a member of the family of natural antimicrobial peptides produced by epithelial cells and participates in the mucosal defensive mechanisms that prevent BT. The aim of the present study was to examine the local and systemic expression of hBD-1 in patients with cirrhosis.

METHODS

Plasma concentrations of hBD-1 and of soluble CD14 (sCD14) proteins were measured by ELISA in patients with chronic viral hepatitis, cirrhosis, and healthy controls. Relative mRNA expression of various natural antimicrobial peptides was determined by real-time PCR in biopsies from the terminal ileum and colon.

RESULTS

We found significant upregulation of hBD-1 and sCD14 in the peripheral blood of patients with cirrhosis compared to patients with chronic viral hepatitis and healthy controls. The etiology of cirrhosis did not affect the concentration of either protein. The levels of hBD-1 protein correlated significantly with the levels of sCD14 in blood collected from hepatic veins of cirrhotic patients. In contrast, no significant differences were observed in the intestinal mucosal mRNA expression of the Paneth cell specific defensin A5 or hBD-1 between patients with cirrhosis and healthy controls.

CONCLUSIONS

hBD-1 is upregulated in patients with cirrhosis and highly correlates with the lipopolysaccharide-induced protein sCD14. hBD-1 may serve as a biomarker of BT in patients with cirrhosis.

Impaired innate immune response of leukocytes from ascitic fluid of patients with spontaneous bacterial peritonitis

An ascitic microenvironment can condition the immune response of cells from cirrhotic patients with spontaneous bacterial peritonitis. To characterize this response, we determined the cytokine concentrations in ascitic fluid and analyzed the phenotype and function of ascitic leukocytes at diagnosis and after antibiotic-induced resolution in sterile ascites and ascitic fluid of 2 spontaneous bacterial peritonitis variants: positive and negative bacteriological culture. At diagnosis, a high concentration was found of IL-6 and IL-10 in the ascitic fluid from negative and positive bacteriological culture. The IL-6 concentration correlated with the percentage of neutrophils (R = 0.686, P < 0.001). In this context, positive and negative culture neutrophils had an impaired oxidative burst, and, after the antibiotic, the negative culture spontaneous bacterial peritonitis burst was fully recovered. Higher concentrations of IL-6 and IL-10 correlated with the presence of low granular CD 14(low) macrophages (R = -0.436, P = 0.005 and R = 0.414, P = 0.007, respectively). Positive culture spontaneous bacterial peritonitis macrophages expressed the lowest levels of CD16, CD86, CD11b and CD206, and HLA-DR, suggesting an impaired global function. Treatment increased all markers on the positive culture macrophages and CD11b and CD86 on negative culture macrophages. In negative culture spontaneous bacterial peritonitis, this increase was accompanied by phagocytic function recovery. The antibiotics then reverted the marker levels on positive and negative culture macrophages to the levels on sterile ascitis macrophages and restored ascitic negative culture cell function.

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.

Role of systemic inflammation in cirrhosis: From pathogenesis to prognosis

The natural history of cirrhosis can be divided into an initial stage, known as compensated cirrhosis, and an advanced stage which encompasses both decompensated cirrhosis and acute-on-chronic liver failure (ACLF). The latter syndrome has been recently described as an acute deterioration of liver function in patients with cirrhosis, which is usually triggered by a precipitating event and results in the failure of one or more organs and high short-term mortality rates. Each stage is characterized by distinctive clinical manifestations and prognoses. One of the key elements involved in cirrhosis physiopathology is systemic inflammation, recently described as one of the components in the cirrhosis-associated immune dysfunction syndrome. This syndrome refers to the combination of immune deficiency and exacerbated inflammation that coexist during the course of cirrhosis and relates to the appearance of clinical complications. Since systemic inflammation is often difficult to assess in cirrhosis patients, new objective, reproducible and readily-available markers are needed in order to optimize prognosis and lengthen survival. Thus, surrogate serum markers and clinical parameters of systemic inflammation have been sought to improve disease follow-up and management, especially in decompensated cirrhosis and ACLF. Leukocyte counts (evaluated as total leukocytes, total eosinophils or neutrophil:lymphocyte ratio) and plasma levels of procalcitonin or C-reactive protein have been proposed as prognostic markers, each with advantages and shortcomings. Research and prospective randomized studies that validate these and other markers are clearly warranted.