Bacterial DNA induces the complement system activation in serum and ascitic fluid from patients with advanced cirrhosis

The Spatial Distribution of Lipophilic Cations in Gradient Copolymers Regulates Polymer-pDNA Complexation, Polyplex Aggregation, and Intracellular pDNA Delivery

Here, we demonstrate that the spatial distribution of lipophilic cations governs the complexation pathways, serum stability, and biological performance of polymer-pDNA complexes (polyplexes). Previous research focused on block/statistical copolymers, whereas gradient copolymers, where the density of lipophilic cations diminishes (gradually or steeply) along polymer backbones, remain underexplored. We engineered gradient copolymers that combine the polyplex colloidal stability of block copolymers with the transfection efficiency of statistical copolymers. We synthesized length- and compositionally equivalent gradient copolymers (G1-G3) along with statistical (S) and block (B) copolymers of 2-(diisopropylamino)ethyl methacrylate and 2-hydroxyethyl methacrylate. We mapped how polymer microstructure governs pDNA loading per polyplex, pDNA conformational changes, and polymer-pDNA binding thermodynamics via static light scattering, circular dichroism spectroscopy, and isothermal titration calorimetry, respectively. While gradient steepness is a powerful design handle to improve polyplex physical properties, augment pDNA delivery capacity, and attenuate polycation-triggered hemolysis, microstructural contrasts did not elicit differences in complement activation.

Dysregulated biomarkers of innate and adaptive immunity predict infections and disease progression in cirrhosis

Background & Aims

Cirrhosis-associated immune dysfunction (CAID) affects both innate and adaptive immunity. This study investigated the complement system, immunoglobulins, and acute-phase proteins and their prognostic relevance in patients with advanced chronic liver disease (ACLD).

Methods

Patients with ACLD (hepatic venous pressure gradient [HVPG] ≥6 mmHg) but without acute decompensation/infections were characterised by HVPG and by clinical EASL stages: compensated (cACLD; S0-2) vs. decompensated ACLD (dACLD) with previous variceal bleeding (S3), non-bleeding decompensation (S4), or further decompensation (S5). Complement factors (C3c, C4, CH50), immunoglobulins (IgA, IgM, IgG, IgG1-4), acute-phase proteins and systemic inflammation biomarkers (white blood cells, C-reactive protein, IL-6, procalcitonin) were measured.

Results

A total of 245 patients (median model for end-stage liver disease score: 11 [9-15], median HVPG: 17 [12-21] mmHg) were included with 150 (61%) presenting dACLD. Complement levels and activity significantly decreased in dACLD substages S4 and S5 (p <0.001). Total IgA/IgM/IgG and IgG1-4 subtype levels increased in patients with dACLD (all p <0.05). Complement and immunoglobulin levels correlated negatively and positively, respectively, with systemic inflammation (all p <0.05). High IgG-1 (adjusted hazard ratio per 100 mg/dl: 1.12, 1.04-1.19, p = 0.002) and IL-6 (adjusted hazard ratio: 1.03, 1.00-1.05, p = 0.023) levels predicted the development of infections during follow-up. High IgA (stratified by median; log-rank p <0.001), high IgG1 (log-rank p = 0.043) and low C3c (log-rank p = 0.003) indicated a higher risk of first/further decompensation or liver-related death (composite endpoint). Next to HVPG and IL-6, low C3c (adjusted hazard ratio per mg/dl: 0.99, 0.97-0.99, p = 0.040) remained independently associated with the composite endpoint on multivariate Cox regression analysis.

Conclusions

Complement levels and immunoglobulins may serve as surrogates of cirrhosis-associated immune dysfunction and associate with cirrhosis severity and systemic inflammation. Low complement C3c predicted decompensation and liver-related death, whereas high IgG-1 indicated an increased risk for infections.

Impact and Implications

Patients with cirrhosis are at increased risk for infections, which worsen their prognosis. We found a significant dysregulation of several essential components of the immune system that was linked to disease severity and indicated a risk for infections and other complications. Simple blood tests identify patients at particularly high risk, who may be candidates for preventive measures.

Clinical Trials Registration

This study is registered at ClinicalTrials.gov (NCT03267615).

Bacterial antigen translocation and age as BMI-independent contributing factors on systemic inflammation in NAFLD patients

BACKGROUND & AIMS

Low-grade systemic inflammation is a crucial landmark in NAFLD favouring disease progression and comorbidities. We evaluated the input of circulating bacterial antigens on systemic markers of inflammation in NAFLD patients.

PATIENTS & METHODS

Multicenter cross-sectional study including consecutive patients with biopsy-proven NAFLD. Demographic, metabolic and fibrosis-related variables were collected. Circulating bacterial antigens were quantified in blood. Toll-like receptor SNPs were genotyped. Serum cytokine levels were evaluated. Peripheral blood mononuclear cell response to bacterial antigens was evaluated in vitro.

RESULTS

Three hundred and fifteen patients from five Spanish hospitals were distributed by BMI. At least, one bacterial antigenic type was found in 66 patients with BMI < 30 (63.4%) and 163 patients with BMI > 30 (77.3%) (P = .014). HOMA-IR was significantly higher in the presence of circulating antigens among patients with BMI < 30. NASH and significant fibrosis in non-obese patients were more frequent in the presence of at least two circulating antigenic types. Allelic frequencies of TLR variants were similar to controls and did not affect clinical or laboratory parameters. Pro-inflammatory cytokines were significantly increased in patients with bacterial antigens, regardless of BMI. TLR gene and protein expression levels were significantly increased in PBMCs from patients with bacterial antigens. Antigen concentrations independently influenced TNF-α and IL-6, in both BMI subgroups of patients. Age independently influenced TNF-α and IL-6 in non-obese patients, and TNF-α in obese patients.

CONCLUSION

Serum circulating bacterial antigens as well as age were BMI-independent factors related to increased systemic inflammation in NAFLD and provides insight on the multifaceted sources of inflammation in these patients.

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.

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.

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.

The soluble mannose receptor is released from the liver in cirrhotic patients, but is not associated with bacterial translocation

BACKGROUND & AIMS

Intestinal bacterial translocation is involved in activation of liver macrophages in cirrhotic patients. Macrophages play a key role in liver inflammation and are involved in the pathogenesis of cirrhosis and complications. Bacterial translocation may be determined by presence of bacterial DNA and macrophage activation, by the soluble mannose receptor. We hypothesize that the soluble mannose receptor is released from hepatic macrophages in cirrhosis and associated with bacterial DNA, portal pressure and complications.

METHODS

We investigated 28 cirrhotic patients set for transjugular intrahepatic portosystemic shunt insertion as a result of refractory ascites (n=17), acute (n=3), or recurrent variceal bleeding (n=8). We analysed plasma from the portal and hepatic veins for bacterial DNA and soluble mannose receptor with qPCR and ELISA.

RESULTS

The median soluble mannose receptor level was elevated in the hepatic vein compared with the portal vein (0.57(interquartile range 0.31) vs 0.55(0.40) mg/L, P=.005). The soluble mannose receptor levels were similar in bacterial DNA-positive and -negative patients. The soluble mannose receptor level in the portal and hepatic veins correlated with the portal pressure prior to transjugular intrahepatic portosystemic shunt insertion (r=.52, P<.008, both) and the levels correlated with Child-Pugh score (r=.63 and r=.56, P<.004, both). We observed higher soluble mannose receptor levels in patients with acute variceal bleeding compared to other indications (P<.05).

CONCLUSION

This study showed hepatic soluble mannose receptor excretion with a higher level in the hepatic than the portal vein, though with no associations to bacterial DNA. We observed associations between soluble mannose receptor levels and portal pressure and higher levels in patients with acute variceal bleeding indicating the soluble mannose receptor as a marker of complications of cirrhosis, but not bacterial translocation.

Microbiome and bacterial translocation in cirrhosis

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

Bifidobacterium pseudocatenulatum CECT7765 induces an M2 anti-inflammatory transition in macrophages from patients with cirrhosis

BACKGROUND & AIMS

Patients with cirrhosis show recurrent access of bacterial products into the bloodstream inducing a multi-altered immunological status leading to relevant complications. We aimed at evaluating Bifidobacterium pseudocatenulatum CECT7765 effect on the host's macrophage function.

PATIENTS & METHODS

Patients with cirrhosis and ascites were included. Granulocyte-macrophage colony-stimulating factor (GM-CSF) monocyte-derived and ascitic fluid (AF) macrophages were cultured with M-CSF, lipopolysaccharide (LPS) and/or the bifidobacterial strain. Pellets and supernatants were evaluated for gene expression of M1 and M2-related genes and cytokine secretion. Cell surface expression molecules were evaluated by flow cytometry. Kupffer cells from bile duct ligated and CCl4 rats were also evaluated.

RESULTS

Experiments were run on GM-CSF blood-derived and AF macrophages from 10 patients with cirrhosis and 10 healthy donors. Different macrophage morphology was observed by optical microscopy in cells stimulated with bifidobacteria vs. LPS. M2-like expression of CD206, CD163 and CD16 was significantly increased in macrophages after stimulation with the bifidobacterial strain vs. LPS. B. pseudocatenulatum CECT7765 was able to significantly change the cytokine secretion pattern of blood-derived and AF macrophages and Kupffer cells from bile duct ligated and CCl4 cirrhotic rats compared to that induced by LPS. B. pseudocatenulatum CECT7765 was also effective in inducing a phenotype transition and a functional change from an M1- to an M2-related gene expression and cytokine secretion pattern in AF macrophages even after LPS-pretreatment. B. pseudocatenulatum CECT7765 did not reduce AF macrophage bacterial killing capacity.

CONCLUSION

B. pseudocatenulatum CECT7765 induces a morphologic, phenotypic and functional transition towards an anti-inflammatory profile in GM-CSF monocyte-derived and AF macrophages from patients with cirrhosis that may help in controlling sustained inflammation in decompensated cirrhosis.

Inflammatory status in human hepatic cirrhosis

This review focuses on new findings about the inflammatory status involved in the development of human liver cirrhosis induced by the two main causes, hepatitis C virus (HCV) infection and chronic alcohol abuse, avoiding results obtained from animal models. When liver is faced to a persistent and/or intense local damage the maintained inflammatory response gives rise to a progressive replacement of normal hepatic tissue by non-functional fibrotic scar. The imbalance between tissue regeneration and fibrosis will determine the outcome toward health recovery or hepatic cirrhosis. In all cases progression toward liver cirrhosis is caused by a dysregulation of mechanisms that govern the balance between activation/homeostasis of the immune system. Detecting differences between the inflammatory status in HCV-induced vs alcohol-induced cirrhosis could be useful to identify specific targets for preventive and therapeutic intervention in each case. Thus, although survival of patients with alcoholic cirrhosis seems to be similar to that of patients with HCV-related cirrhosis (HCV-C), there are important differences in the altered cellular and molecular mechanisms implicated in the progression toward human liver cirrhosis. The predominant features of HCV-C are more related with those that allow viral evasion of the immune defenses, especially although not exclusively, inhibition of interferons secretion, natural killer cells activation and T cell-mediated cytotoxicity. On the contrary, the inflammatory status of alcohol-induced cirrhosis is determined by the combined effect of direct hepatotoxicity of ethanol metabolites and increases of the intestinal permeability, allowing bacteria and bacterial products translocation, into the portal circulation, mesenteric lymph nodes and peritoneal cavity. This phenomenon generates a stronger pro-inflammatory response compared with HCV-related cirrhosis. Hence, therapeutic intervention in HCV-related cirrhosis must be mainly focused to counteract HCV-immune system evasion, while in the case of alcohol-induced cirrhosis it must try to break the inflammatory loop established at the gut-mesenteric lymph nodes-peritoneal-systemic axis.

Immunomodulating effects of antibiotics used in the prophylaxis of bacterial infections in advanced cirrhosis

The use of norfloxacin either as primary or secondary prophylaxis of bacterial infections in advanced cirrhosis has improved patient’s survival. This may be explained not only due to a significant decrease in the number of infections, but also because of a direct immunomodulatory effect. Selective intestinal decontamination with norfloxacin reduces translocation of either viable bacteria or bacteria-driven products from the intestinal lumen. In addition, norfloxacin directly modulates the systemic inflammatory response. The pro-inflammatory cytokine profile secreted by neutrophils from these patients shows a close, significant, and inverse correlation with serum norfloxacin levels. Similar effects have been described with other quinolones in different clinical conditions. Although the underlying mechanisms are not well defined for most of the antibiotics, the pathways triggered for norfloxacin to induce such immunomodulatory effects involve the down-regulation of pro-inflammatory inducible nitric oxide synthase, cyclooxygenase-2, and NF-κB and the up-regulation of heme-oxygenase 1 and IL-10 expression. The knowledge of these immunomodulatory effects, additional to their bactericidal role, improves our comprehension of the interaction between antibiotics and the cellular host response and offer new possibilities for the development of new therapeutic strategies to manage and prevent bacterial infections in cirrhosis.

Effects of polysaccharide intercellular adhesin (PIA) in an ex vivo model of whole blood killing and in prosthetic joint infection (PJI): A role for C5a

BACKGROUND

A major complication of using medical devices is the development of biofilm-associated infection caused by Staphylococcus epidermidis where polysaccharide intercellular adhesin (PIA) is a major mechanism of biofilm accumulation. PIA affects innate and humoral immunity in isolated cells and animal models. Few studies have examined these effects in prosthetic joint infection (PJI).

METHODS

This study used ex vivo whole blood modelling in controls together with matched-serum and staphylococcal isolates from patients with PJI.

RESULTS

Whole blood killing of PIA positive S. epidermidis and its isogenic negative mutant was identical. Differences were unmasked in immunosuppressed whole blood pre-treated with dexamethasone where PIA positive bacteria showed a more resistant phenotype. PIA expression was identified in three unique patterns associated with bacteria and leukocytes, implicating a soluble form of PIA. Purified PIA reduced whole blood killing while increasing C5a levels. In clinically relevant staphylococcal isolates and serum samples from PJI patients; firstly complement C5a was increased 3-fold compared to controls; secondly, the C5a levels were significantly higher in serum from PJI patients whose isolates preferentially formed PIA-associated biofilms.

CONCLUSIONS

These data demonstrate for the first time that the biological effects of PIA are mediated through C5a in patients with PJI.

Secondary biliary cholestasis promotes testicular macrophage infiltration and autophagy in rats

PROBLEM

Cholestasis can cause translocation of gut bacteria, and endotoxemia, and systemic inflammation. Now, little is known about the effects of cholestasis on the testicular inflammation and autophagy.

METHODS

A rat biliary cholestasis model caused by common bile duct ligation (CBDL), together with biliary decompression (choledochoduodenostomy), was used.

RESULTS

The magnitude of MCP-1 expression and CD68(+) macrophage infiltration within testes was progressively up-regulated in rats along with increasing duration of CBDL and was maintained at relatively high level in rats with biliary decompression. The large up-regulation of testicular ATG-12, LC3II, and autophagic vacuoles was found with the extending duration of CBDL and kept at 5 weeks following biliary decompression. The autophagic contents were a large accumulation of mitophagy in testes in rats with CBDL, and cytosol components in rats with biliary decompression.

CONCLUSION

Secondary biliary cholestasis can promote inflammatory reaction and the activation of mitophagy and autophagy in testes.

Disease dependent qualitative and quantitative differences in the inflammatory response to ascites occurring in cirrhotics

AIM: To assess differing patterns and levels of ascitic fluid cyctokine and growth factors exist between those with a high risk and low risk of spontaneous bacterial peritonitis (SBP).

METHODS: A total of 57 consecutive patients with ascites requiring a large volume paracentesis were studied. Their age, gender, specific underlying disease conditions were recorded after a review of their clinical records. Each underwent a routine assessment prior to their paracentesis consisting of a complete blood count, complete metabolic profile and prothrombin time/international normalized ratio (INR) determination. The ascitic fluid was cultured and a complete cell count and albumin determination was obtained on the fluid. In addition, blood and ascitic fluid was assessed for the levels of interleukin interleukin (IL)-1A, IL-1B, IL-2, IL-4, IL-8, IL-10, monocyte chemotactic protein (MCP)-1, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) utilizing the Randox Biochip platforms (Boston, MA). A serum-ascites gradient, for each cytokine and growth factor was calculated. The results are reported as mean ± SEM between disease groups with statistical analysis consisting of the student t-test (two tailed) with a P value of 0.05 defining significance.

RESULTS: No clinically important demographic or biochemical differences between the 4 groups studied were evident. In contrast, marked difference in the cytokine and growth factors levels and pattern were evident between the 4 disease groups. Individuals with alcoholic cirrhosis had the highest levels of IL-1A, IL-1B, IL-4, IFNγ. Those with malignant disease had the highest levels of IL-2. Those with hepatitis C virus (HCV) associated cirrhosis had the highest value for IL-6, IL-8, IL-10, MCP-1 and VEGF. Those with cardiac disease had the highest level of TNF-α and EGF. The calculated serum- ascites gradients for the cardiac and malignant disease groups had a greater frequency of negative values signifying greater levels of IL-8, IL-10 and MCP-1 in ascites than did those with alcohol or HCV disease.

CONCLUSION: These data document important differences in the cytokine and growth factor levels in plasma, ascitic fluid and the calculated plasma - ascites fluid gradients in cirrhotics requiring a large volume paracentesis. These differences may be important in determining the risk for bacterial peritonitis.

Anti-C5a complementary peptide ameliorates acute peritoneal injury induced by neutralization of Crry and CD59

In peritoneal dialysis (PD) therapy, physical stresses such as exposure to peritoneal dialysate, catheter trauma, and peritonitis may induce peritoneal injury that can prevent continued long-term PD therapy. Therefore, protection of the peritoneum is an important target to enable long-term PD therapy in patients with end-stage renal disease. We previously showed that neutralization of the membrane complement regulators (CRegs) Crry and CD59 in rat peritoneum provokes development of acute peritoneal injury due to uncontrolled complement activation. C5a is a key effecter molecule of the complement system released during acute inflammation. Control of C5a has been proposed as a strategy to suppress inflammatory reactions and, because peritoneal injury is accompanied by inflammation, we hypothesized that C5a targeted therapy might be an effective way to suppress peritoneal injury. In the present study we used an established acute peritonitis model induced by neutralization of CRegs to investigate the effects on acute peritoneal injury of inhibiting C5a. Intravenous administration of an anti-C5a complementary peptide (AcPepA) up to 4 h after induction of injury significantly and dose-dependently prevented accumulation of inflammatory cells and reduced tissue damage in the model, accompanied by decreased C3b deposition. We show that C5a contributed to the development of peritoneal injury. Our results suggest that C5a is a target for preventing or treating peritoneal injury in patients undergoing prolonged PD therapy or with infectious complications.

No difference in portal and hepatic venous bacterial DNA in patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt insertion

BACKGROUND

Bacterial translocation (BT) with immune activation may lead to hemodynamical alterations and poor outcomes in patients with cirrhosis.

AIMS

We investigated bacterial DNA (bDNA), a marker of BT, and its relation to portal pressure and markers of inflammation in the portal and hepatic veins in patients with cirrhosis undergoing TIPS insertion.

METHODS

We analysed plasma for bDNA and markers of inflammation in 28 patients [median portal pressure gradient 15 (11-19) mmHg] during TIPS treatment for refractory ascites (n = 19) or acute variceal bleeding (n = 9). Advanced cirrhosis was present in the majority [Child-Pugh class (A/B/C): 1/14/13], and most often caused by alcohol (n = 21).

RESULTS

bDNA was detectable in one or both samples in 16 of 28 patients (57%). bDNA was present in 39% of the samples from the portal vein vs 43% of the samples in the hepatic vein (P = 0.126). Antibiotics had no effect on bDNA or markers of inflammation. Markers of inflammation did not differ between the hepatic and portal veins with the exceptions of soluble urokinase plasminogen activating receptor (suPAR) and vascular endothelial growth factor (VEGF), both higher in the hepatic vein (P = 0.031 and 0.003 respectively).

CONCLUSIONS

No transhepatic gradient of bDNA was evident, suggesting that no major hepatic elimination of bDNA occurs in advanced liver disease. bDNA, in contrast to previous reports was largely unrelated to a panel of markers of inflammation and without relation to portal pressure.

Hepatorenal syndrome

INTRODUCTION

Renal failure in cirrhosis is a common complication that is associated with poor survival. A rapid diagnosis of the cause of renal failure is mandatory because it is associated with prognosis.

AREAS COVERED

This review covers the differential diagnosis between hepatorenal syndrome (HRS) and other causes of renal failure, as well as the difficulty in making a correct diagnosis, caused by the differentiation between hepatorenal syndrome and acute tubular necrosis. This review also discusses the multifactorial mechanisms involved in the pathogenesis of HRS. The paper provides diagnostic algorithms to use in clinical practice, emphasized by the fact that some patients may have HRS superimposed on pre-existent renal failure.

EXPERT OPINION

The correct diagnosis of renal failure is essential to initiate the correct treatment of this complication. In patients with HRS type 1, treatment with vasopressin and albumin is the treatment of choice; however, 50% of patients do not respond to this treatment.

Identification of bacterial DNA in noninfectious pleural fluid with a highly sensitive PCR method

BACKGROUND

Bacterial DNA due to bacterial translocation has been identified in noninfectious ascitic fluid samples.

OBJECTIVE

This study investigated the possible presence of bacterial DNA in the pleural fluid of patients with pleural effusions of noninfectious origin, using a highly sensitive PCR-based method.

METHODS

Pleural fluid samples from 175 patients (average age ± SD: 69 ± 14 years) with noninfectious pleural effusion (62 transudates, 113 exudates) were analyzed. Bacterial DNA was detected using nested PCR with amplification of a fragment of the gene r16S, with 2 amplification protocols, i.e. low sensitivity (10 and 40 cycles) and high sensitivity (40 and 40 cycles).

RESULTS

With the less sensitive amplification process, only 1 sample was positive (Haemophilus parainfluenzae in a patient with hepatic hydrothorax). With the highly sensitive nested PCR method, bacterial DNA was identified in the pleural fluid, of both transudative and exudative origin, of 75 of the 175 patients (43%). In cases of isolation of a single bacterium, the more frequent were Escherichia coli, Salmonella enterica and Streptococcus pneumoniae.

CONCLUSIONS

Regardless of its origin, bacterial DNA can be identified in almost half of noninfectious pleural effusions by using a highly sensitive PCR-based method. The possible clinical significance or prognostic value of these findings deserves to be evaluated.

Soluble membrane attack complex in ascites in patients with liver cirrhosis without infections

AIM

To study complement activation in 46 patients with alcoholic cirrhosis and ascites but no spontaneous bacterial peritonitis (SBP) and 10 healthy controls.

METHODS

Complement activation was determined by the measurement of soluble membrane attack complex (sMAC) concentrations in ascites and plasma. In patients, metabolic liver function was determined by the galactose elimination capacity and the clinical status assessed by the Model of End-Stage Liver Disease and Child-Pugh scores.

RESULTS

Ascites sMAC levels were markedly higher than in the corresponding plasma sample (median (range): 596 (170 - 1519) vs 160 (77 - 848) μg/L; P < 0.01). Ascites sMAC levels correlated positively with liver status. There was no relationship between ascites sMAC and leukocyte count. No relationship between ascites sMAC and blood C-reactive protein, albumin or neutrophile count was found. Plasma sMAC concentrations were slightly higher in patients than in controls [130 μg/L (70 - 204); P = 0.04]. Neither sMAC in ascites nor plasma was related to mortality.

CONCLUSION

The increased sMAC concentration in ascites and plasma indicate an activation of the complement system in cirrhosis even in the absence of SBP. This was particularly evident in the peritoneal fluid and most marked in patients with preserved liver status. The high ascites sMAC levels may reflect transudation of membrane attack complexes from the liver. Whether this complement activation has any clinical implications remains to be clarified.

Bacterial DNA in patients with cirrhosis and noninfected ascites mimics the soluble immune response established in patients with spontaneous bacterial peritonitis

Bacterial infections and severity of associated inflammatory reaction influence prognosis in patients with advanced cirrhosis. We compared the innate immune response to bacterial DNA (bactDNA) translocation with that caused by viable bacteria translocation in patients with spontaneous bacterial peritonitis and the relationship between the cytokine response and serum levels of bactDNA. The bactDNA translocation was investigated in 226 patients with cirrhosis and noninfected ascites, 22 patients with spontaneous bacterial peritonitis, and 10 patients with ascites receiving continuous norfloxacin. Serum and ascitic fluid tumor necrosis factor alpha, interferon-gamma, interleukin-12, and nitric oxide metabolites were measured via enzyme-linked immunosorbent assay. Bacterial genomic identifications were made via amplification and sequencing of the 16S ribosomal RNA gene and digital quantization with DNA Lab-on-chips. The bactDNA was present in 77 noninfected patients (34%) and in all cases of spontaneous bacterial peritonitis, even in those with culture-negative ascitic fluid. No patient receiving norfloxacin showed bactDNA translocation. Levels of all cytokines were similar in patients with bactDNA translocation or spontaneous bacterial peritonitis and significantly higher than in patients without bactDNA or in those receiving norfloxacin. Serum bactDNA concentration paralleled levels of all cytokines and nitric oxide in a series of patients with bactDNA translocation or spontaneous bacterial peritonitis followed during 72 hours. Antibiotic treatment in the series of patients with spontaneous bacterial peritonitis did not abrogate bactDNA translocation in the short term.

CONCLUSION

bactDNA translocation-associated cytokine response is indistinguishable from that in patients with spontaneous bacterial peritonitis and is dependent on bactDNA concentration. Norfloxacin abrogates bactDNA translocation and cytokine response.

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

BACKGROUND/AIMS

Serum lipopolysaccharide-binding protein and bacterial-DNA have been proposed as markers of bacterial translocation and this study aimed to evaluate the immune response registered by bacterial-DNA from Gram-positive and Gram-negative microorganisms and the effect on lipopolysaccharide-binding protein, to further investigate both markers.

METHODS

Thirty-two patients were distributed into two groups according to the presence of bacterial-DNA, determined by broad-range PCR of 16SrRNA gene. Serum endotoxin, lipopolysaccharide-binding protein, cytokines and nitric oxide products were measured by ELISA.

RESULTS

Serum endotoxin and lipopolysaccharide-binding protein were non-significantly higher in patients with bacterial-DNA than in those without bacterial-DNA. Regarding patients with bacterial-DNA from Gram-positive microorganisms (n = 8), these levels were similar to those in patients without bacterial-DNA (n = 16), and significantly lower than in patients with bacterial-DNA from Gram-negative bacteria. Tumour necrosis factor-alpha and interleukin-6 were significantly increased in patients with vs without bacterial-DNA (324.93+/-70.76 vs 134.91+/-34.58microg/mL; p<0.05; 294.96+/-87.48 vs 175.92+/-60.58microg/mL, p < 0.05, respectively). Patients with bacterial-DNA from Gram-positive microorganisms also showed significantly higher levels for both cytokines than patients without bacterial-DNA, and similar to those in patients with bacterial-DNA from Gram-negative bacteria.

CONCLUSIONS

Patients with translocation of bacterial-DNA from Gram-positive microorganisms showed increased proinflammatory cytokines unrelated to endotoxin, which would not be detected by serum lipopolysaccharide-binding protein measurement.

Translocation of bacterial DNA from Gram-positive microorganisms is associated with a species-specific inflammatory response in serum and ascitic fluid of patients with cirrhosis

Translocation of bacterial-DNA in patients with cirrhosis and ascites triggers an innate immune response. Identification of characteristics to which this response is sensitive is relevant from a clinical standpoint. The aim of this study has been to determine if the proinflammatory immune response established in vivo in cirrhotic patients with ascites as a consequence of bacterial-DNA translocation is related to the identified bacterial species and their frequency of cytosine-guanosine content in serum and ascitic fluid. Patients with advanced cirrhosis and ascites were included in the study and distributed into groups I and II according to the absence or presence of bacterial-DNA translocation, respectively. Serum and ascitic fluid levels of proinflammatory cytokines after normalization of bacterial-DNA concentration and the activated form of nuclear factor-kappa B in ascitic fluid pellets were measured by enzyme-linked immunosorbent assay techniques. Translocation of bacterial-DNA with higher cytosine-guanosine content induced the highest cytokine response, which was higher than that in patients without bacterial-DNA translocation. The activated form of nuclear factor-kappa B in ascitic fluid pellets of patients with bacterial-DNA translocation was greater in patients with higher bacterial-DNA cytosine-guanosine content, whereas the amount of total nuclear factor-kappa B remained unaltered. Bacterial-DNA translocation induces a marked immune reaction in vivo in patients with advanced cirrhosis and ascites which is related, among other factors, to the bacterial-DNA cytosine-guanosine content. Therefore, the host's immune response to bacterial-DNA translocation constitutes a species-specific phenomenon.