Increased serum nitrite and nitrate levels in patients with cirrhosis: relationship to endotoxemia

Pharmacologic Treatment of Portal Hypertension

Portal hypertension is the key mechanism driving the transition from compensated to decompensated cirrhosis. In this review, the authors described the pathophysiology of portal hypertension in cirrhosis and the rationale of pharmacologic treatment of portal hypertension. We discussed both etiologic and nonetiologic treatment of portal hypertension and the specific clinical scenarios how nonselective beta-blocker can be used in patients with cirrhosis. Finally, the authors summarized the evidence for emerging alternatives for portal hypertension in patients with cirrhosis.

Association between endotoxemia and blood no in the portal circulation of cirrhotic patients: results of a pilot study

Pathophysiology of portal vein thrombosis (PVT) in cirrhosis is still not entirely understood. Elevated levels of lipopolysaccharides (LPS) in portal circulation are significantly associated with hypercoagulation, increased platelet activation and endothelial dysfunction. The aim of the study was to investigate if LPS was associated with reduced portal venous flow, the third component of Virchow's triad, and the underlying mechanism. Serum nitrite/nitrate, as a marker of nitric oxide (NO) generation, and LPS were measured in the portal and systemic circulation of 20 patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt (TIPS) procedure; portal venous flow velocity (PVV) was also measured in each patient and correlated with NO and LPS levels. Serum nitrite/nitrate and LPS were significantly higher in the portal compared to systemic circulation; a significant correlation was found between LPS and serum nitrite/nitrate (R = 0.421; p < 0.01). Median PVV before and after TIPS was 15 cm/s (6-40) and 31 cm/s (14-79), respectively. Correlation analysis of PVV with NO and LPS showed a statistically significant negative correlation of PVV with portal venous NO concentration (R = - 0.576; p = 0.020), but not with LPS. In vitro study with endothelial cells showed that LPS enhanced endothelial NO biosynthesis, which was inhibited by L-NAME, an inhibitor of NO synthase, or TAK-242, an inhibitor of TLR4, the LPS receptor; this effect was accomplished by up-regulation of eNOS and iNOS. The study shows that in cirrhosis, endotoxemia may be responsible for reduced portal venous flow via overgeneration of NO and, therefore, contribute to the development of PVT.

Gut Microbiota and Biomarkers of Endothelial Dysfunction in Cirrhosis

Our aim was to study the association of endothelial dysfunction biomarkers with cirrhosis manifestations, bacterial translocation, and gut microbiota taxa. The fecal microbiome was assessed using 16S rRNA gene sequencing. Plasma levels of nitrite, big endothelin-1, asymmetric dimethylarginine (ADMA), presepsin, and claudin were measured as biomarkers of endothelial dysfunction, bacterial translocation, and intestinal barrier dysfunction. An echocardiography with simultaneous determination of blood pressure and heart rate was performed to evaluate hemodynamic parameters. Presepsin, claudin 3, nitrite, and ADMA levels were higher in cirrhosis patients than in controls. Elevated nitrite levels were associated with high levels of presepsin and claudin 3, the development of hemodynamic circulation, hypoalbuminemia, grade 2-3 ascites, overt hepatic encephalopathy, high mean pulmonary artery pressure, increased abundance of Proteobacteria and Erysipelatoclostridium, and decreased abundance of Oscillospiraceae, Subdoligranulum, Rikenellaceae, Acidaminococcaceae, Christensenellaceae, and Anaerovoracaceae. Elevated ADMA levels were associated with higher Child-Pugh scores, lower serum sodium levels, hypoalbuminemia, grade 2-3 ascites, milder esophageal varices, overt hepatic encephalopathy, lower mean pulmonary artery pressure, and low abundance of Erysipelotrichia and Erysipelatoclostridiaceae. High big endothelin-1 levels were associated with high levels of presepsin and sodium, low levels of fibrinogen and cholesterol, hypocoagulation, increased Bilophila and Coprobacillus abundances, and decreased Alloprevotella abundance.

Mechanisms and treatment approaches for ACLF

Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome characterized by decompensation of cirrhosis, severe systemic inflammation and organ failures. ACLF is frequently triggered by intra- and/or extrahepatic insults, such as bacterial infections, alcohol-related hepatitis or flares of hepatic viruses. The imbalance between systemic inflammation and immune tolerance causes organ failures through the following mechanisms: (i) direct damage of immune cells/mediators; (ii) worsening of circulatory dysfunction resulting in organ hypoperfusion and (iii) metabolic alterations with prioritization of energetic substrates for inflammation and peripheral organ 'energetic crisis'. Currently, the management of ACLF includes the support of organ failures, the identification and treatment of precipitating factors and expedited assessment for liver transplantation (LT). Early LT should be considered in patients with ACLF grade 3, who are unlikely to recover with the available treatments and have a mortality rate > 70% at 28 days. However, the selection of transplant candidates and their prioritization on the LT waiting list need standardization. Future challenges in the ACLF field include a better understanding of pathophysiological mechanisms leading to inflammation and organ failures, the development of specific treatments for the disease and personalized treatment approaches. Herein, we reviewed the current knowledge and future perspectives on mechanisms and treatment of ACLF.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL TRIAL NUMBER

NCT03267615.

Mechanisms of immunity in acutely decompensated cirrhosis and acute-on-chronic liver failure

The identification of systemic inflammation (SI) as a central player in the orchestration of acute-on-chronic liver failure (ACLF) has opened new avenues for the understanding of the pathophysiological mechanisms underlying this disease condition. ACLF, which develops in patients with acute decompensation of cirrhosis, is characterized by single or multiple organ failure and high risk of short-term (28-day) mortality. Its poor outcome is closely associated with the severity of the systemic inflammatory response. In this review, we describe the key features of SI in patients with acutely decompensated cirrhosis and ACLF, including the presence of a high blood white cell count and increased levels of inflammatory mediators in systemic circulation. We also discuss the main triggers (i.e. pathogen- and damage-associated molecular patterns), the cell effectors (i.e. neutrophils, monocytes and lymphocytes), the humoral mediators (acute phase proteins, cytokines, chemokines, growth factors and bioactive lipid mediators) and the factors that influence the systemic inflammatory response that drive organ failure and mortality in ACLF. The role of immunological exhaustion and/or immunoparalysis in the context of exacerbated inflammatory responses that predispose ACLF patients to secondary infections and re-escalation of end-organ dysfunction and mortality are also reviewed. Finally, several new potential immunogenic therapeutic targets are debated.

Gut Microbiota and Infectious Complications in Advanced Chronic Liver Disease: Focus on Spontaneous Bacterial Peritonitis

Liver cirrhosis is a chronic disease that can be complicated by episodes of decompensation such as variceal bleeding, hepatic encephalopathy, ascites, and jaundice, with subsequent increased mortality. Infections are also among the most common complications in cirrhotic patients, mostly due to a defect in immunosurveillance. Among them, one of the most frequent is spontaneous bacterial peritonitis (SBP), defined as the primary infection of ascitic fluid without other abdominal foci. SBP is mainly induced by Gram-negative bacteria living in the intestinal tract, and translocating through the intestinal barrier, which in cirrhotic patients is defective and more permeable. Moreover, in cirrhotic patients, the intestinal microbiota shows an altered composition, poor in beneficial elements and enriched in potentially pathogenic ones. This condition further promotes the development of leaky gut and increases the risk of SBP. The first-line treatment of SBP is antibiotic therapy; however, the antibiotics used have a broad spectrum of action and may adversely affect the composition of the gut microbiota, worsening dysbiosis. For this reason, the future goal is to use new therapeutic agents that act primarily on the gut microbiota, selectively modulating it, or on the intestinal barrier, reducing its permeability. In this review, we aim to describe the reciprocal relationship between gut microbiota and SBP, focusing on pathogenetic aspects but also on new future therapies.

Etiology and Management of Edema: A Review

The development of peripheral edema can often pose a significant diagnostic and therapeutic challenge for practitioners due to its association with a wide variety of underlying disorders ranging in severity. Updates to the original Starling's principle have provided new mechanistic insights into edema formation. Additionally, contemporary data highlighting the role of hypochloremia in the development of diuretic resistance provide a possible new therapeutic target. This article reviews the pathophysiology of edema formation and discusses implications for treatment.

Gut dysbiosis, endotoxemia and clotting activation: A dangerous trio for portal vein thrombosis in cirrhosis

Liver cirrhosis (LC) is associated with portal venous thrombosis (PVT) in roughly 20% of cirrhotic patients but the underlying mechanism is still unclear. Low-grade endotoxemia by lipopolysaccharides (LPS), a component of outer gut microbiota membrane, is detectable in the portal circulation of LC and could predispose to PVT. LPS may translocate into systemic circulation upon microbiota dysbiosis-induced gut barrier dysfunction, that is a prerequisite for enhanced gut permeability and ensuing endotoxemia. Experimental and clinical studies provided evidence that LPS behaves a pro-thrombotic molecule so promoting clotting and platelet activation. Experiments conducted in the portal circulation of cirrhotic patients showed the existence of LPS-related enhanced thrombin generation as well as endothelial dysfunction, venous stasis, and platelet activation. The review will analyze 1) the pro-thrombotic role of endotoxemia in the context of LC 2) the biological plausibility linking endotoxemia with PVT and 3) the potentially interventional tools to lower endotoxemia and eventually hypercoagulation.

Escherichia/Shigella, SCFAs, and Metabolic Pathways-The Triad That Orchestrates Intestinal Dysbiosis in Patients with Decompensated Alcoholic Cirrhosis from Western Mexico

Gut microbiota undergoes profound alterations in alcohol cirrhosis. Microbiota-derived products, e.g., short chain fatty acids (SCFA), regulate the homeostasis of the gut-liver axis. The objective was to evaluate the composition and functions of the intestinal microbiota in patients with alcohol-decompensated cirrhosis. Fecal samples of 18 patients and 18 healthy controls (HC) were obtained. Microbial composition was characterized by 16S rRNA amplicon sequencing, SCFA quantification was performed by gas chromatography (GC), and metagenomic predictive profiles were analyzed by PICRUSt2. Gut microbiota in the cirrhosis group revealed a significant increase in the pathogenic/pathobionts genera Escherichia/Shigella and Prevotella, a decrease in beneficial bacteria, such as Blautia, Faecalibacterium, and a decreased α-diversity (p < 0.001) compared to HC. Fecal SCFA concentrations were significantly reduced in the cirrhosis group (p < 0.001). PICRUSt2 analysis indicated a decrease in acetyl-CoA fermentation to butyrate, as well as an increase in pathways related to antibiotics resistance, and aromatic amino acid biosynthesis. These metabolic pathways have been poorly described in the progression of alcohol-related decompensated cirrhosis. The gut microbiota of these patients possesses a pathogenic/inflammatory environment; therefore, future strategies to balance intestinal dysbiosis should be implemented. These findings are described for the first time in the population of western Mexico.

Cirrhosis-associated immune dysfunction

The term cirrhosis-associated immune dysfunction (CAID) comprises the distinctive spectrum of immune alterations associated with the course of end-stage liver disease. Systemic inflammation and immune deficiency are the key components of CAID. Their severity is highly dynamic and progressive, paralleling cirrhosis stage. CAID involves two different immune phenotypes: the low-grade systemic inflammatory phenotype and the high-grade systemic inflammatory phenotype. The low-grade systemic inflammatory phenotype can be found in patients with compensated disease or clinical decompensation with no organ failure. In this phenotype, there is an exaggerated immune activation but the effector response is not markedly compromised. The high-grade systemic inflammatory phenotype is present in patients with acute-on-chronic liver failure, a clinical situation characterized by decompensation, organ failure and high short-term mortality. Along with high-grade inflammation, this CAID phenotype includes intense immune paralysis that critically increases the risk of infections and worsens prognosis. The intensity of CAID has important consequences on cirrhosis progression and correlates with the severity of liver insufficiency, bacterial translocation and organ failure. Therapies targeting the modulation of the dysfunctional immune response are currently being evaluated in preclinical and clinical studies.

Influence of Probiotics Administration Before Liver Resection in Patients with Liver Disease: A Randomized Controlled Trial

BACKGROUND

By inhibiting the growth of pathogenic bacteria and modulating the local intestinal immune system, probiotics may reduce bacterial translocation and systemic endotoxaemia, factors partially responsible for post-operative complications following liver resection for hepatocellular carcinoma in patients with cirrhosis.

METHODS

Patients with resectable hepatocellular carcinoma developed in the setting of chronic liver disease were prospectively divided into two equal-sized groups: one receiving probiotic treatment 14 days prior to surgery and the other receiving placebo. The primary endpoint was the level of circulating endotoxins after hepatectomy. Secondary endpoints were systemic inflammation (inflammatory cytokine levels), post-operative liver function and overall post-operative complication rate.

RESULTS

From May 2013 to December 2018, 64 patients were randomized, and 54 patients were included in the analysis, 27 in each arm. No significant change in endotoxin levels was observed over time in either group (P = 0.299). No difference between the groups in terms of post-operative liver function and overall complication rates was observed. The only differences observed were significant increases in the levels of TNFalpha (P = 0.019) and interleukin 1-b (P = 0.028) in the probiotic group in the post-operative period.

CONCLUSION

Contrary to the modest data reported in the literature, the administration of probiotics before minor liver resection for hepatocellular carcinoma developed in the setting of compensated chronic liver disease does not seem to have an impact on circulating endotoxin levels or post-operative complication rates.

TRIAL REGISTRATION

Trial registration: NCT02021253.

Phosphodiesterases in the Liver as Potential Therapeutic Targets of Cirrhotic Portal Hypertension

Liver cirrhosis is a frequent condition with high impact on patients' life expectancy and health care systems. Cirrhotic portal hypertension (PH) gradually develops with deteriorating liver function and can lead to life-threatening complications. Other than an increase in intrahepatic flow resistance due to morphological remodeling of the organ, a functional dysregulation of the sinusoids, the smallest functional units of liver vasculature, plays a pivotal role. Vascular tone is primarily regulated by the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, wherein soluble guanylate cyclase (sGC) and phosphodiesterase-5 (PDE-5) are key enzymes. Recent data showed characteristic alterations in the expression of these regulatory enzymes or metabolite levels in liver cirrhosis. Additionally, a disturbed zonation of the components of this pathway along the sinusoids was detected. This review describes current knowledge of the pathophysiology of PH with focus on the enzymes regulating cGMP availability, i.e., sGC and PDE-5. The results have primarily been obtained in animal models of liver cirrhosis. However, clinical and histochemical data suggest that the new biochemical model we propose can be applied to human liver cirrhosis. The role of PDE-5 as potential target for medical therapy of PH is discussed.

Role of the cytochrome P-450/ epoxyeicosatrienoic acids pathway in the pathogenesis of renal dysfunction in cirrhosis

Background

Hepatorenal syndrome (HRS) is a life-threatening complication of advanced liver cirrhosis that is characterized by hemodynamic alterations in the kidney and other vascular beds. Cytochrome P(CYP)-450 enzymes metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acids. These eicosanoids regulate blood pressure, vascular tone and renal tubular sodium transport under both physiological and pathophysiological states.

Methods

Experiments were performed to investigate the role of the CYP system in the pathogenesis of renal dysfunction during cirrhosis. Rats underwent bile duct ligation (BDL) or sham surgery and were studied at 2, 4 and 5 weeks post-surgery. In additional experiments, post-BDL rats were treated with three daily intraperitoneal doses of either the selective epoxygenase inhibitor N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MSPPOH) or a vehicle, starting on Day 22 after surgery.

Results

BDL led to progressive renal dysfunction that was associated with reduced renal cortical perfusion but without any overt histologic changes, consistent with HRS. CYP isoform enzyme expression was significantly altered in BDL rats. In the kidney, CYP2C23 expression was upregulated at both the mRNA and protein levels in BDL rats, while CYP2C11 was downregulated. Histologically, the changes in CYP2C23 and CYP2C11 expression were localized to the renal tubules. EET production was increased in the kidneys of BDL rats as assessed by urinary eicosanoid levels. Finally, treatment with the selective epoxygenase inhibitor MSPPOH significantly reduced renal function and renal cortical perfusion in BDL rats, suggesting a homeostatic role for epoxygenase-derived eicosanoids.

Conclusions

The CYP/EET pathway might represent a novel therapeutic target for modulating renal dysfunction in advanced cirrhosis.

Pericytes in the Gut

This review chapter describes the current knowledge about the nature of pericytes in the gut, their interaction with endothelial cells in blood vessels, and their pathophysiological functions in the setting of chronic liver disease. In particular, it focuses on the role of these vascular cell types and related molecular signaling pathways in pathological angiogenesis associated with liver disease and in the establishment of the gut-vascular barrier and the potential implications in liver disease through the gut-liver axis.

Infections in Cirrhosis

Purpose of review

Patients with cirrhosis are at high risk of developing serious infections. Bacterial infections remain the most common cause of morbidity and mortality in these patients. This review is focused on the prevalence of infections in those with cirrhosis, including multidrug-resistant (MDR) pathogens, pathogenesis of infection-related acute-on-chronic liver failure (ACLF), current treatment recommendations, and prophylactic strategies in patients with cirrhosis.

Recent findings

Recent epidemiological studies have noted an emerging prevalence of MDR bacterial infections and associated with poor prognosis, and a high rate of treatment failure and mortality. Therefore, new recommendations on empirical antibiotic use based on epidemiological data have been developed in order to improve outcomes.

Summary

Spontaneous bacterial peritonitis (SBP) and urinary tract infection (UTI) are the most frequent infections followed by pneumonia, cellulitis, and bacteremia, while pneumonia carries the highest risk of mortality. The incidence of MDR bacterial infections has been increasing, especially in healthcare-associated settings. Second infections that develop during hospitalization, multiple organ failures, and high MELD score are associated with poor survival. Preventive measures, early diagnosis, and adequate treatment of infections are essential key concepts in minimizing morbidity and mortality in patients with cirrhosis.

Quantitative measurement of selected protein biomarkers of endothelial dysfunction in plasma by micro-liquid chromatography-tandem mass spectrometry based on stable isotope dilution method

The aim of this study was to develop and validate the novel microLC/MS-MRM method for the simultaneous quantification of six proteins: angiopoietin 2 (Angpt-2), soluble form of fms-like tyrosine kinase 1 (sFLT-1), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA), endocan (ESM-1), soluble form of E-selectin (sE-sel), and one peptide: adrenomedullin (ADM) in mouse plasma. Two approaches were compared: a stable isotope dilution (SID) method- used as a reference and a modified SID (mSID) procedure. In SID strategy the calibration curves were used, whereas in mSID the ratio between the chromatogram peak area of endogenous tryptic peptides at unknown concentration to chromatogram peak area of exogenous, stable isotope-labelled internal standards (SISs) added to the sample at known concentration was calculated. The microLC/MS-MRM method in the SID approach was linear from 0.250 pmol/mL to 250 pmol/mL for Angpt-2; 5 pmol/mL to 5000 pmol/mL for sFLT-1; 2.5 pmol/mL to 5000 pmol/mL for PAI-1; 0.375 pmol/mL to 250 pmol/mL for t-PA; 0.375 pmol/mL to 187.5 pmol/mL for ESM-1; 2.5 pmol/mL to 5000 pmol/mL for sE-sel and 0.375 pmol/mL to 250 pmol/mL for ADM. LPS-induced changes in plasma assessed based on SID and mSID approaches gave comparable quantitative results and featured LPS-induced dysregulation of endothelial permeability (Angpt-2, sFLT-1), glycocalyx injury (SDC-1) accompanied by a pro-thrombotic response (PAI-1). In addition, we applied microLC/MS-MRM method with mSID strategy to analyze human plasma samples from patients with chronic myeloid leukemia (CML) and obstructive sleep apnoea (OSA) and demonstrated usefulness of the method to characterize endothelial function in humans. In conclusion, the microLC/MS-MRM method with mSID strategy applied for simultaneous quantification of protein biomarkers of endothelial function in plasma represents a novel targeted proteomic platform for the comprehensive evaluation of endothelial function in mice and humans.

Rush progression and fatal result of septic shock related to central line catheter infection in cirrhosis patient with brain stroke

BACKGROUND

Catheter-related blood stream infection (CRBSI) is one of the most common intractable healthcare-associated infections because catheters can be easily contaminated by resistant bacteria, and is associated with a high mortality. Central lines are currently used for administering medication to patients with severe stroke, and may thus cause CRBSI.

CASE PRESENTATION

A 71-year-old woman with cirrhosis presented with subarachnoid hemorrhage (SAH) that was treated by clipping surgery. On postoperative day (POD) 38, sudden high fever (40.3 °C) was detected; the patient died a few hours later. Blood and central line cultures were positive for Klebsiella pneumoniae that may have caused CRBSI and endotoxin shock. In this case, the duration from fever detection to death was notably short. Additionally, inflammatory markers such as white blood cells (WBC) or C-reactive protein (CRP) were almost within normal ranges, even a few hours after fever was detected and before death. Cirrhosis was considered to be the cause of these phenomena.

CONCLUSION

The timely diagnosis and complete treatment of patients with liver cirrhosis who develop CRBSI are highly challenging. We suggest that clinicians should rigorously apply preventive measures and strengthen CRBSI monitoring, especially in cirrhosis-associated cases.

[Hyponatremia in Liver Cirrhosis]

Hyponatremia is a commonly observed complication that is related to hypoalbuminemia and portal hypertension in patients with advanced liver cirrhosis. Hyponatremia in patients with liver cirrhosis is mostly dilutional hyponatremia and is defined when the serum sodium concentration is below 130 meq/L. The risk of complications increases significantly in cirrhotic patients with hyponatremia, which includes spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatic encephalopathy. In addition, hyponatremia is associated with increased morbidity and mortality in patients with cirrhosis, and is an important prognostic factor before and after liver transplantation. The conventional therapies of hyponatremia are albumin infusion, fluid restriction and loop diuretics, but these are frequently ineffective. This review investigates the pathophysiology and various therapeutic modalities, including selective vasopressin receptor antagonists, for the management of hyponatremia in patients with liver cirrhosis.

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.

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.

Inhibition of nitric oxide production reverses diabetes-induced Kupffer cell activation and Klebsiella pneumonia liver translocation

Klebsiella pneumoniae (KP) is the most common pathogen of pyogenic liver abscess in East and Southeast Asia and diabetes mellitus (DM) is a major risk factor. The effect and mechanism of diabetes on KP liver abscess was examined in streptozotocin-induced diabetic mice and Akita mice (C57BL/6J-Ins2^Akita). KP translocation to liver and plasma alaine transaminase levels were increased and liver clearance of KP was decreased in DM mice. Diabetic mice exhibited overgrowth of Enterococcus as well as E.coli and decreased lactobacilli/bifidas growth in intestine, increased intestinal iNOS protein and nitrite levels in portal vein, and increased IL-1β and TNF-α expression of Kupffer cells. Fructooligosaccharides (FOS) or dead L. salivarius (dLac) supplementation reversed diabetes-induced enteric dysbiosis, NO levels in portal vein, and KP translocation to liver. L-NAME treatment decreased intestinal iNOS protein expression as well as Kupffer cell activation and increased liver clearance of KP in DM mice. Dead E.coli (2×10⁸ CFU/ml) feeding for one week induced iNOS and TLR4 expression of intestine in germ-free (GF) mice. Dead bacteria feeding induced IL-1β and TNF-α expression of Kupffer cells in GF mice but not in GF TLR4^-/- mice. In conclusion, balance of intestinal microflora is important for preventing intestinal iNOS expression, Kupffer cell activation, and KP liver translocation in diabetes. Reversal of diabetes-induced enteric dysbiosis with FOS or dead L. salivarius decreases diabetes-induced intestinal iNOS expression and KP liver translocation. Diabetes induces Kupffer cell activation and KP liver translocation through enteric dysbiosis and nitric oxide production.

Immune Dysfunction in Cirrhosis

Cirrhosis due to any etiology disrupts the homeostatic role of liver in the body. Cirrhosis-associated immune dysfunction leads to alterations in both innate and acquired immunity, due to defects in the local immunity of liver as well as in systemic immunity. Cirrhosis-associated immune dysfunction is a dynamic phenomenon, comprised of both increased systemic inflammation and immunodeficiency, and is responsible for 30% mortality. It also plays an important role in acute as well as chronic decompensation. Immune paralysis can accompany it, which is characterized by increase in anti-inflammatory cytokines and suppression of proinflammatory cytokines. There is also presence of increased gut permeability, reduced gut motility and altered gut flora, all of which leads to increased bacterial translocation. This increased bacterial translocation and consequent endotoxemia leads to increased blood stream bacterial infections that cause systemic inflammatory response syndrome, sepsis, multiorgan failure and death. The gut microbiota of cirrhotic patients has more pathogenic microbes than that of non-cirrhotic individuals, and this disturbs the homeostasis and favors gut translocation. Prompt diagnosis and treatment of such infections are necessary for better survival. We have reviewed the various mechanisms of immune dysfunction and its consequences in cirrhosis. Recognizing the exact pathophysiology of immune dysfunction will help treating clinicians in avoiding its complications in their patients and can lead to newer therapeutic interventions and reducing the morbidity and mortality rates.

Gut microbiome and liver disease

Gut microbiota changes are important in determining the occurrence and progression of chronic liver disease related to alcohol, nonalcoholic fatty liver disease, and cirrhosis. Specifically, the systemic inflammation, endotoxemia, and the vasodilation that leads to complications such as spontaneous bacterial peritonitis and hepatic encephalopathy could be related to the gut milieu. Given the poor prognosis of these events, their prevention and early management are essential. Microbiota may be an essential component of the gut milieu that can impact these clinical events, and the study of their composition and function in a culture-independent manner could help understand the prognosis. Recent human and animal studies have shown that the relative abundance and the functional changes of microbiota in the stool, colonic mucosa, and saliva have varying consequences on the presence and prognosis of chronic liver disease and cirrhosis. The impact of therapies on the microbiota is slowly being understood and will likely lead to a more targeted approach to gut microbiota modification in chronic liver disease and cirrhosis.

Immune function biomarker QuantiFERON-monitor is associated with infection risk in cirrhotic patients

AIM

To investigate whether a novel immune function biomarker QuantiFERON-Monitor (QFM) can identify cirrhotic patients at greatest risk of infection.

METHODS

Adult cirrhotic patients on the liver transplant waiting list were recruited for this observational cohort study from a tertiary liver transplant referral unit. The immune function biomarker, QFM was performed using the same method as the widely available Quantiferon-gold assay, and measures output in interferon gamma in IU/mL after dual stimulation of the innate and adaptive immune systems. Ninety-one cirrhotic patients were recruited, with 47 (52%) transplanted on the day of their QFM. The remaining 44 (48%) were monitored for infections until transplant, death, or census date of 1st February 2014.

RESULTS

Cirrhotic patients express a median QFM significantly lower than healthy controls (94.5 IU/mL vs 423 IU/mL), demonstrating that they are severely immunosuppressed. Several factors including model for end stage liver disease, presence of hepatocellular carcinoma, bilirubin, international normalized ratio and haemoglobin were associated with QFM on univariate analysis. Disease aetiology did not appear to impact QFM. On multivariate analysis, only Child-Pugh score and urea were significantly associated with a patient's immune function as objectively measured by QFM. In the 44 patients who were not transplanted immediately after their blood test and could be monitored for subsequent infection risk, 13 (29.5%) experienced a pre-transplant infection a median 20 d (range 2-182) post-test. QFM < 214 IU/mL was associated with HR = 4.1 (P = 0.01) for infection. A very low QFM < 30 IU/mL was significantly associated (P = 0.003) with death in three patients who died while awaiting transplantation (HR = 56.6).

CONCLUSION

QFM is lower in cirrhotics, allowing objective determinations of an individual's unique level of immune dysfunction. Low QFM was associated with increased susceptibility to infection.

Grade of soluble inflammatory response is mainly affected by circulating bacterial DNA concentrations in cirrhosis

BACKGROUND & AIMS

Patients with decompensated cirrhosis show a marked innate immune response that shows a wide variability. The reasons for this fact have not been previously evaluated. This investigation was undertaken to study factors influencing the immune response intensity in both serum and ascitic fluid in patients with cirrhosis and ascites with presence of bactDNA.

METHODS

77 patients with cirrhosis and presence of bactDNA fragments in blood and ascitic fluid were included. Identification of bactDNA was evaluated by 16SrRNA gene PCR followed by nucleotide sequencing and by species-specific PCR. Concentration of amplified bacterial-DNA, bacteria identification, LPS, TNF-alpha, IFN-gamma, Interleukin 12 and nitric oxide in serum and ascitic fluid were evaluated as factors related to intensity of the immune response.

RESULTS

Serum and AF levels of bactDNA, TNF-α, IFN-γ and nitric oxide concentration were higher in patients with presence of bactDNA from gram negative bacteria. Serum TNF-α levels showed a significant correlation with concentrations of bactDNA (r = 0.88; P = 0.001) and LPS (r = 0.28; P = 0.016). Serum nitric oxide levels were also significantly correlated with concentrations of bactDNA (r = 0.761; P = 0.001) but not with LPS levels. Levels of INF-γ and IL-12 were not significantly correlated with either bactDNA nor LPS levels. Plasmatic concentration of bactDNA was the most accurately correlated factor with the inflammatory response (ancova model included only levels of bactDNA (r(2) = 0.87, P = 0.047 for TNF-α; r(2) = 0.45, P = 0.03 for NOx).

CONCLUSIONS

Bacterial-DNA concentration is the most influencing variable associated with serum TNF-α and nitric oxide response.

Hepatorenal Syndrome: Diagnosis and Treatment - newsreel

Hepatorenal syndrome (HRS) is defined as renal failure that occurs in the presence of severe acute or chronic liver disease in the absence of underlying renal pathology. Due to the functional nature of the disease and the absence of specific diagnostic markers, HRS diagnosis is determined based on positive criteria associated with excluding other causes of renal failure in patients with liver cirrhosis and ascites. Differentiation from other types of acute or chronic renal disease is extremely difficult and therapeutic options are limited, prophylactic behavior is most appropriate in patients with severe hepatic disease and risk factors for the installation of hepatorenal syndrome. Highlighting all precipitating factors of acute renal insufficiency and therapeutic modalities in order to minimize adverse events is an important step in improving the follow-up of the patients with liver cirrhosis. The prognosis is reserved especially for type 1 HRS. Liver transplantation is the best option for patients without contraindications. The therapies introduced in recent years, such as vasoconstrictor drugs or transjugular intrahepatic portosystemic shunt are effective methods in the renal function improvement.

Mechanisms of decompensation and organ failure in cirrhosis: From peripheral arterial vasodilation to systemic inflammation hypothesis

The peripheral arterial vasodilation hypothesis has been most influential in the field of cirrhosis and its complications. It has given rise to hundreds of pathophysiological studies in experimental and human cirrhosis and is the theoretical basis of life-saving treatments. It is undisputed that splanchnic arterial vasodilation contributes to portal hypertension and is the basis for manifestations such as ascites and hepatorenal syndrome, but the body of research generated by the hypothesis has revealed gaps in the original pathophysiological interpretation of these complications. The expansion of our knowledge on the mechanisms regulating vascular tone, inflammation and the host-microbiota interaction require a broader approach to advanced cirrhosis encompassing the whole spectrum of its manifestations. Indeed, multiorgan dysfunction and failure likely result from a complex interplay where the systemic spread of bacterial products represents the primary event. The consequent activation of the host innate immune response triggers endothelial molecular mechanisms responsible for arterial vasodilation, and also jeopardizes organ integrity with a storm of pro-inflammatory cytokines and reactive oxygen and nitrogen species. Thus, the picture of advanced cirrhosis could be seen as the result of an inflammatory syndrome in contradiction with a simple hemodynamic disturbance.

Gut Microbiota and Host Reaction in Liver Diseases

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

Signaling and stress: The redox landscape in NOS2 biology

Nitric oxide (NO) has a highly diverse range of biological functions from physiological signaling and maintenance of homeostasis to serving as an effector molecule in the immune system. However, deleterious as well as beneficial roles of NO have been reported. Many of the dichotomous effects of NO and derivative reactive nitrogen species (RNS) can be explained by invoking precise interactions with different targets as a result of concentration and temporal constraints. Endogenous concentrations of NO span five orders of magnitude, with levels near the high picomolar range typically occurring in short bursts as compared to sustained production of low micromolar levels of NO during immune response. This article provides an overview of the redox landscape as it relates to increasing NO concentrations, which incrementally govern physiological signaling, nitrosative signaling and nitrosative stress-related signaling. Physiological signaling by NO primarily occurs upon interaction with the heme protein soluble guanylyl cyclase. As NO concentrations rise, interactions with nonheme iron complexes as well as indirect modification of thiols can stimulate additional signaling processes. At the highest levels of NO, production of a broader range of RNS, which subsequently interact with more diverse targets, can lead to chemical stress. However, even under such conditions, there is evidence that stress-related signaling mechanisms are triggered to protect cells or even resolve the stress. This review therefore also addresses the fundamental reactions and kinetics that initiate signaling through NO-dependent pathways, including processes that lead to interconversion of RNS and interactions with molecular targets.

Hyponatremia in Cirrhosis--Pathogenesis, Treatment, and Prognostic Significance

Cirrhosis is characterized by systemic and splanchnic vasodilation that leads to excessive nonosmotic secretion of vasopressin (antidiuretic hormone). Hyponatremia is a common electrolyte abnormality in advanced liver disease that results from the impaired ability of the kidney to excrete solute-free water that leads to "dilutional" hyponatremia-water retention disproportionate to the retention of sodium. Hyponatremia in liver diseases carries the prognostic burden, correlates with the severity of cirrhosis, and, in recent studies, has also been implicated in the pathogenesis of hepatic encephalopathy. The current treatment options are limited to conventional therapies like fluid restriction, and the outcomes are unsatisfactory. Although currently available vasopressin (V2 receptors) antagonists have been shown to increase serum sodium concentrations and improve ascites control, their role in the treatment of hyponatremia in liver disease patients remains questionable because of adverse effect profiles, high cost, and poor data on long-term mortality benefits. More information is needed to argue the benefits vs risks of short-term use of vaptans for correction of hyponatremia especially just hours-to-days before liver transplant.

The Kidney in Pediatric Liver Disease

There is an intricate relationship between the liver and the kidney, with renal physiology and function intimately involved in many primary disorders of pediatric liver disease. The hemodynamic changes of progressive cirrhosis affect and are directly affected by changes in renal blood flow and renal handling of sodium and free water excretion. Resulting complications of worsening ascites, hyponatremia, and acute kidney injury frequently complicate the care of children with advanced liver disease and contribute significant morbidity and mortality. While liver transplantation may restore hemodynamic stability, nearly 40% of pediatric liver transplant recipients develop chronic kidney disease post-transplant and approximately 25% are left with clinical hypertension. This review seeks to provide a basic understanding of this relationship to enable the provision of optimal care to children with liver disease.

Sepsis-induced acute kidney injury in patients with cirrhosis

Acute kidney injury (AKI) is a common and life-threatening complication in patients with cirrhosis. Recently, new criteria for the diagnosis of AKI have been proposed in patients with cirrhosis by the International Club of Ascites. Almost all types of bacterial infections can induce AKI in patients with cirrhosis representing its most common precipitating event. The bacterial infection-induced AKI usually meets the diagnostic criteria of hepatorenal syndrome (HRS). Well in keeping with the "splanchnic arterial vasodilation hypothesis", it has been stated that HRS develops as a consequence of a severe reduction of effective circulating volume related to splanchnic arterial vasodilation and to an inadequate cardiac output. Nevertheless, the role of bacterial infections in precipitating organ failures, including renal failure, is enhanced when their course is characterized by the development of a systemic inflammatory response syndrome (SIRS), thus, when sepsis occurs. Sepsis has been shown to be capable to induce "per se" AKI in animals as well as in patients conditioning also the features of renal damage. This observation suggests that when precipitated by sepsis, the pathogenesis and the clinical course of AKI also in patients with cirrhosis may differentiate to a certain extent from AKI with another or no precipitating factor. The purpose of this review is to describe the features of AKI precipitated by bacterial infections and to highlight whether infection and/or the development of SIRS may influence its clinical course, and, in particular, the response to treatment.

Gut-liver axis in liver cirrhosis: How to manage leaky gut and endotoxemia

A “leaky gut” may be the cutting edge for the passage of toxins, antigens or bacteria into the body, and may play a pathogenic role in advanced liver cirrhosis and its complications. Plasma endotoxin levels have been admitted as a surrogate marker of bacterial translocation and close relations of endotoxemia to hyperdynamic circulation, portal hypertension, renal, cardiac, pulmonary and coagulation disturbances have been reported. Bacterial overgrowth, increased intestinal permeability, failure to inactivate endotoxin, activated innate immunity are all likely to play a role in the pathological states of bacterial translocation. Therapeutic approach by management of the gut-liver axis by antibiotics, probiotics, synbiotics, prebiotics and their combinations may improve the clinical course of cirrhotic patients. Special concern should be paid on anti-endotoxin treatment. Adequate management of the gut-liver axis may be effective for prevention of liver cirrhosis itself by inhibiting the progression of fibrosis.

Pathophysiology of Portal Hypertension

The bases of our current knowledge on the physiology of the hepatic portal system are largely owed to the work of three pioneering vascular researchers from the sixteenth and the seventeenth centuries: A. Vesalius, W. Harvey, and F. Glisson. Vesalius is referred to as the founder of modern human anatomy, and in his influential book, De humani corporis fabrica libri septem, he elaborated the first anatomical atlas of the hepatic portal venous system (Vesalius 2013). Sir William Harvey laid the foundations of modern cardiovascular research with his Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Harvey 1931) in which he established the nature of blood circulation. Finally, F. Glisson characterized the gastrointestinal-hepatic vascular system (Child 1955). These physiological descriptions were later complemented with clinical observations. In the eighteenth and nineteenth centuries, Morgagni, Puckelt, Cruveilhier, and Osler were the first to make the connection between common hepatic complications – ascites, splenomegaly, and gastrointestinal bleeding – and obstruction of the portal system (Sandblom 1993). These were the foundations that allowed Gilbert, Villaret, and Thompson to establish an early definition of portal hypertension at the beginning of the twentieth century. In this period, Thompson performed the first direct measurement of portal pressure by laparotomy in some patients (Gilbert and Villaret 1906; Thompson et al. 1937). Considering all these milestones, and paraphrasing Sir Isaac Newton, if hepatologists have seen further, it is by standing on the shoulders of giants.

Nowadays, our understanding of the pathogenesis of portal hypertension has largely improved thanks to the progress in preclinical and clinical research. However, this field is ever-changing and hepatologists are continually identifying novel pathological mechanisms and developing new therapeutic strategies for this clinical condition. Hence, the aim of this chapter is to summarize the current knowledge about this clinical condition.

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.

Effect of biliary cirrhosis on neurogenic relaxation of rat gastric fundus and anococcygeus muscle: role of nitric oxide pathway

BACKGROUND

Cirrhosis, associated with a host of hemodynamic abnormalities, could affect the gastrointestinal (GI) tract motility. On the other hand, the nonadrenergic noncholinergic (NANC) neurotransmission has been shown to play a pivotal role in GI tract motility and has been linked with release of nitric oxide (NO) on electrical stimulation. In this study, we investigated the effect of biliary cirrhosis on the neurogenic relaxation of rat gastric fundus and anococcygeus muscle and also the possible role of nitric oxide system in this manner.

METHODS

Isolated gastric fundus and anococcygeus strips of sham-operated and biliary cirrhotic (4 weeks after bile duct ligation) rats were mounted under tension in a standard organ bath. Electrical stimulation was applied to obtain NANC-mediated relaxations in precontracted gastric fundus and anococcygeus muscle. The neurogenic relaxations were examined in the presence of different doses of NO synthase inhibitor, N (w)-Nitro-L-Arginine Methyl Ester (L-NAME). The concentration-dependent relaxant responses to the NO donor sodium nitroprusside were also evaluated.

RESULTS

The neurogenic relaxation of both gastric fundus and anococcygeus muscle was significantly (P < 0.001) increased in cirrhotic animals. L-NAME (0.03-1,000 µM) inhibited relaxations in both groups in a dose-dependent manner (P < 0.001), but cirrhotic groups were more resistant to the inhibitory effects of L-NAME (P < 0.01). Sodium nitroprusside-mediated relaxations were similar in two groups.

CONCLUSIONS

This study for the first time demonstrated that cirrhosis increases the NO-mediated neurogenic relaxation of both rat gastric fundus and anococcygeus muscle, suggesting a crucial role for the neurogenic NO in the pathophysiology of disturbed GI motility in cirrhosis.

Prostaglandin F₂α modulates atrial chronotropic hyporesponsiveness to cholinergic stimulation in endotoxemic rats

Endotoxemia induces various physiological adaptive responses such as tachycardia. There is evidence to show that inflammatory tachycardia might be linked to a direct action of prostanoids on the cardiac pacemaker cells. Recent reports have indicated that systemic inflammation may uncouple of cardiac pacemaker from cholinergic neural control in experimental animals; however, the exact mechanism of this phenomenon is uncertain. This study was aimed to explore the hypothesis that prostanoids modulate atrial chronotropic hyporesponsiveness to cholinergic stimulation in endotoxemic rats. Male albino rats were given intraperitoneal injection of either saline or lipopolysaccharide (LPS, 1 mg/kg). 3 h after saline or LPS injection, the atria were isolated and chronotropic responsiveness to cholinergic stimulation was evaluated in an organ bath. The expression of atrial cyclooxygenases (COX)-1, COX-2 and COX-3 mRNA was assessed by quantitative real-time RT-PCR and cytosocalcium-dependent phospholipase A₂ (cPLA₂) activity was measured in the atria. The expression of atrial COX-2 mRNA and cPLA₂ activity increased significantly in endotoxemic atria (P<0.05). Incubation with prostaglandin F₂α (PGF₂α, 100 pM) could significantly decrease chronotropic response to cholinergic stimulation in vitro. Likewise, LPS injection could induce a significant hyporesponsiveness to cholinergic stimulation, and incubation of isolated atria with either indomethacin (5 µM) or AL-8810 (a PGF₂α antagonist, 10 µM) could reverse it (P<0.01, P<0.05, respectively), while SQ29548 (a thromboxane A₂ antagonist, 10 nM) was failed (P>0.05). Our data showed that PGF₂α may contribute to the atrial chronotropic hyporesponsiveness to cholinergic stimulation in endotoxemic rats.

New determinants of prognosis in bacterial infections in cirrhosis

Despite major advances in the knowledge and management of liver diseases achieved in recent decades, decompensation of cirrhosis still carries a high burden of morbidity and mortality. Bacterial infections are one of the main causes of decompensation. It is very important for clinical management to be aware of the population with the highest risk of poor outcome. This review deals with the new determinants of prognosis in patients with cirrhosis and bacterial infections reported recently. Emergence of multiresistant bacteria has led to an increasing failure rate of the standard empirical antibiotic therapy recommended by international guidelines. Moreover, it has been recently reported that endothelial dysfunction is associated with the degree of liver dysfunction and, in infected patients, with the degree of sepsis. It has also been reported that relative adrenal insufficiency is frequent in the non-critically ill cirrhotic population and it is associated with a higher risk of developing infection, severe sepsis, hepatorenal syndrome and death. We advise a change in the standard empirical antibiotic therapy in patients with high risk for multiresistant infections and also to take into account endothelial and adrenal dysfunction in prognostic models in hospitalized patients with decompensated cirrhosis.

Could serum nitrate and nitrite levels possibly predict hepatorenal syndrome in hepatitis C virus-related liver cirrhosis?

PURPOSE

This study aimed to determine whether serum levels of nitric oxide metabolites (nitrates and nitrites) correlate with renal dysfunction in patients with liver cirrhosis and, moreover, to assess nitric oxide metabolite (NOx) power for predicting hepatorenal syndrome (HRS) in such patients.

METHODS

Among patients admitted to the Tropical Medicine Department, Ain Shams University Hospital, a total of 60 patients with chronic hepatitis C-related liver cirrhosis were included in this study. Patients were divided into three groups. Group I included 20 patients with compensated liver cirrhosis (CLC). Group II included 20 patients with decompensated liver cirrhosis (DLC). Group III included 20 patients with decompensated liver cirrhosis and HRS. Twenty healthy subjects with no clinical or laboratory evidence of liver disease were enrolled as a control group (group IV).

RESULTS

Patients with HRS had a higher mean nitrite levels followed by DLC, then CLC, and then controls. The sensitivity and specificity of NO metabolites (nitrites) were 100 % and 93.3 %, respectively, with accuracy of 95 % at cutoff value of 387 μmol/L for diagnosing patients with HRS. There was a highly significant statistical difference between patients positive and negative for nitrites as regards renal profile (p = 0.000).

CONCLUSION

A strong relation between nitrite cutoff value and renal dysfunction in liver cirrhosis has been found. Also, patients with HRS had higher mean serum nitrite levels than decompensated liver cirrhosis or compensated liver cirrhosis, raising the possibility of using nitrate and nitrite levels as a predictor for HRS in HCV-related liver cirrhosis.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Intestinal epithelial barrier function in liver cirrhosis: an extensive review of the literature

Recent evidence suggests that translocation of bacteria and bacterial products, such as endotoxin from the intestinal lumen into the systemic circulation is a contributing factor in the pathogenesis of chronic liver diseases and the development of complications in cirrhosis. In addition to alterations in the intestinal microbiota and immune system, dysfunction of the intestinal epithelial barrier may be an important factor facilitating bacterial translocation. This review aims to provide an overview of the current evidence of intestinal epithelial barrier dysfunction in human chronic liver diseases and cirrhosis, and to discuss possible contributing factors and mechanisms. Data suggest the presence of intestinal epithelial barrier dysfunction in patients with chronic liver diseases, but are more convincing in patients with cirrhosis, especially in those with complications. The barrier dysfunction can result from both direct and indirect effects of aetiological factors, such as alcohol and obesity, which can cause chronic liver diseases and ultimately cirrhosis. On the other hand characteristics of cirrhosis itself, including portal hypertension, alterations in the intestinal microbiota, inflammation and oxidative stress can affect barrier function of both small and large intestine and may contribute to the development of complications. In conclusion, there are indications for intestinal epithelial barrier dysfunction in patients with chronic liver diseases and especially in patients with cirrhosis, which can be caused by various factors affecting both the small and large intestine.

Diagnostic significance of nitrates and nitrites and L-arginine, in development of hepatorenal syndrome in patients with end stage alcoholic liver cirrhosis

Hepatorenal syndrome (HRS) represents a complication of the end-stage liver cirrhosis. The aim of the present study was to analyze concentrations of nitrates and nitrites (NO2 + NO3) and L-arginine in patients with liver cirrhosis and HRS as a possible predictive marker for the development of HRS. The research was performed in a group of 28 patients with cirrhosis and HRS, a group of 22 patients suffering from cirrhosis without HRS and a control group comprised of 42 healthy voluntary blood donors. In patients with end-stage alcoholic liver cirrhosis, with HRS, the concentrations of NO2 + NO3 increased and correlated with the degree of cirrhosis progression, compared to patients without HRS and significantly higher compared to the control group. The level of NO2 + NO3 was in a positive correlation with the degree of liver damage de Ritis coefficient (HRS = 0.72; cirrhosis: = 0.55; control = -0.10). Significant positive correlation was found between NO2 + NO3 concentration and inflammatory marker C-reactive protein (HRSC = 0.75; cirrhosis = 0.70, control = -0.25). The correlation between NO2 + NO3 concentration and creatinine concentration in patients with HRS was significantly higher compared to patients without HRS (HRS = 0.82; cirrhosis = 0.32; control = -0.25). By using binary regression analysis, on the basis of clinical criteria of HRS diagnosis, the strongest independent positive predictor for HRS development was NO2 + NO3, associated with 45.02 times higher incidence of HRS, compared to arginine (12.7 times higher incidence), creatinine (13.1 times higher incidence), and AST/ALT ratio (10.55 higher incidence of HRS). Since the determination of NO2 + NO3 represents a reliable and easily applicable method, it may be used as an early predictive marker for HRS development.