Intestinal mucosal alterations in experimental cirrhosis in the rat: role of oxygen free radicals

Compared with other methods, cyanoacrylate and lauromacrogol in treating esophagogastric varices did not increase the risk of postoperative infection

BACKGROUND

Patients with cirrhosis commonly undergo endoscopic cyanoacrylate injection for gastric and esophageal variceal bleeding. However, postoperative infections can increase the risk of rebleeding and mortality.

AIM

This study aimed to determine the risk of postoperative infections and its associated factors following cyanoacrylate injection treatment in these patients.

METHODS

A retrospective analysis was conducted on 57 patients treated with ligation (ligation group), 66 patients treated with cyanoacrylate injection (injection group), and 91 patients treated with conservative treatment (control group) at the Nanchong Central Hospital.

RESULTS

The rate of postoperative infection was similar among the cyanoacrylate, ligation, and conservative treatment groups, with no significant statistical difference observed (P = 0.97). Multivariate analysis identified postoperative Child-Pugh score and renal insufficiency as two independent risk factors for postoperative infection. The rebleeding rate in the injection group was significantly lower than in the other groups (P = 0.01). Mortality was significantly higher in the control group compared with the ligation and injection groups (P = 0.01).

CONCLUSION

Cyanoacrylate combined with lauromacrogol injection did not significantly increase the risk of infection compared with ligation and conservative treatments, and it was more effective in reducing the risk of rebleeding. This method is safe, effective, and holds clinical value for broader application.

Oxidative Mechanisms and Cardiovascular Abnormalities of Cirrhosis and Portal Hypertension

In patients with portal hypertension, there are many complications including cardiovascular abnormalities, hepatorenal syndrome, ascites, variceal bleeding, and hepatic encephalopathy. The underlying mechanisms are not yet completely clarified. It is well known that portal hypertension causes mesenteric congestion which produces reactive oxygen species (ROS). ROS has been associated with intestinal mucosal injury, increased intestinal permeability, enhanced gut bacterial overgrowth, and translocation; all these changes result in increased endotoxin and inflammation. Portal hypertension also results in the development of collateral circulation and reduces liver mass resulting in an overall increase in endotoxin/bacteria bypassing detoxication and immune clearance in the liver. Endotoxemia can in turn aggravate oxidative stress and inflammation, leading to a cycle of gut barrier dysfunction → endotoxemia → organ injury. The phenotype of cardiovascular abnormalities includes hyperdynamic circulation and cirrhotic cardiomyopathy. Oxidative stress is often accompanied by inflammation; thus, blocking oxidative stress can minimize the systemic inflammatory response and alleviate the severity of cardiovascular diseases. The present review aims to elucidate the role of oxidative stress in cirrhosis-associated cardiovascular abnormalities and discusses possible therapeutic effects of antioxidants on cardiovascular complications of cirrhosis including hyperdynamic circulation, cirrhotic cardiomyopathy, and hepatorenal syndrome.

Vitamin D protects intestines from liver cirrhosis-induced inflammation and oxidative stress by inhibiting the TLR4/MyD88/NF-κB signaling pathway

Liver cirrhosis affects the structures and physiological functions of the intestine. Our previous study revealed that liver injury inhibited 25-hydroxylation of vitamin D (25(OH)-VD). The aim of this study was to investigate the roles and mechanisms of vitamin D in liver cirrhosis-induced intestinal injury. The rat liver cirrhosis model was established through the administration of carbon tetrachloride (CCl₄) for 8 weeks. Hematoxylin-eosin staining was performed to unveil the intestinal injury induced by liver cirrhosis. Enzyme-linked immunosorbent and reverse transcription PCR (RT-PCR) analysis were used to determine the levels of 25(OH)-VD, vitamin D receptor, Cytochrome P450 24A1 (CYP24A1), and α-defensin 5 (DEFA5) in rat and human serum of liver cirrhosis. Furthermore, liver cirrhosis rats were treated with low-dose (500 IU/kg) and high-dose (2,000 IU/kg) vitamin D intraperitoneally. The expression levels of TLR4/MyD88/NF-κB signaling pathway were evaluated by RT-PCR and Western blot. In conclusion, we determined the deficiency of vitamin D and down-regulation of DEFA5 and intestinal damage induced by liver cirrhosis. Moreover, vitamin D effectively inhibited liver cirrhosis-induced intestinal inflammation and oxidative stress through the TLR4/MyD88/NF-κB pathway. Vitamin D might be a promising therapeutic strategy for future treatment of liver-induced intestinal injury.

The shaping of gut immunity in cirrhosis

Cirrhosis is the common end-stage of chronic liver diseases of different etiology. The altered bile acids metabolism in the cirrhotic liver and the increase in the blood-brain barrier permeability, along with the progressive dysbiosis of intestinal microbiota, contribute to gut immunity changes, from compromised antimicrobial host defense to pro-inflammatory adaptive responses. In turn, these changes elicit a disruption in the epithelial and gut vascular barriers, promoting the increased access of potential pathogenic microbial antigens to portal circulation, further aggravating liver disease. After summarizing the key aspects of gut immunity during homeostasis, this review is intended to update the contribution of liver and brain metabolites in shaping the intestinal immune status and, in turn, to understand how the loss of homeostasis in the gut-associated lymphoid tissue, as present in cirrhosis, cooperates in the advanced chronic liver disease progression. Finally, several therapeutic approaches targeting the intestinal homeostasis in cirrhosis are discussed.

Protective Effect of Oyster Peptides Derived From Crassostrea gigas on Intestinal Oxidative Damage Induced by Cyclophosphamide in Mice Mediated Through Nrf2-Keap1 Signaling Pathway

Oyster peptide (OP) has exhibited useful biological activities and can be used in multi-functional foods. OP has been reported to play a significant role in intestinal protection, but its specific mechanism is still not completely understood. The aim of this study was to analyze the potential effect of OP on oxidative damage of mice intestine induced by cyclophosphamide (Cy). The experimental results revealed that intragastric administration of OP significantly increased average bodyweight, improved ileum tissue morphology and villus structure, as well as increased the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in oxidized mice serum and liver. The content of malondialdehyde (MDA) in the mice serum and liver homogenate was found to be markedly decreased. Moreover, OP significantly increased the relative mRNA expression levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-P_X), quinone oxidoreductase (NQO1) and heme oxidase-1 (HO-1) in ileum. Western-blot results indicated that prior administration of OP significantly up-regulated the Nrf2 production in ileum, and substantially decreased then Keap1 gene expression. In conclusion, intake of OP was found to markedly improve intestinal oxidative stress in vivo, and this effect was primarily mediated through the simulation of antioxidant Nrf2-Keap1 signaling pathway. This study is beneficial to the application of peptide nutrients in the prevention or mitigation of intestinal oxidative damage.

Visualising and quantifying intestinal permeability -where do we stand

Intestinal permeability is getting more and more attention in gastrointestinal research. Although well recognized, its exact role in health and disease is yet to be defined. There are many methods of quantifying intestinal permeability, but most of them fail to deliver tangible information about the morphological integrity of the intestinal barrier. In this review we aim to describe imaging options for the assessment of intestinal barrier integrity and their potential relevance for clinical practice. Our focus is on confocal laser endomicroscopy, which is at this time the only method for visualizing not only functional but also morphological aspects of the gut barrier in vivo.

Intestinal Barrier and Permeability in Health, Obesity and NAFLD

The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.

Active Vitamin D3 Treatment Attenuated Bacterial Translocation via Improving Intestinal Barriers in Cirrhotic Rats

SCOPE

Pathological bacterial translocation from the disrupted intestinal barrier leads to substantial complications and mortality in liver cirrhosis. Vitamin D is reported as beneficial to gut barriers in some animal models. However, its effect on cirrhotic bacterial translocation is unknown. The authors aim to investigate the effects of calcitriol on bacterial translocation in cirrhotic rats.

METHODS AND RESULTS

Cirrhotic rats are administrated with a 2-week course of active vitamin D3 (calcitriol, 0.1 μg kg-1  per day) or vehicle by oral gavage after thioacetamide (TAA) injection for 16 weeks. Bacterial translocation, gut permeability, gut microbiota, and associated mechanisms are investigated. Calcitriol treatment significantly attenuates bacterial translocation and reduces intestinal permeability in TAA-induced cirrhotic rats. It upregulates the expressions of occludin in the small intestine and claudin-1 in the colon of cirrhotic rats directly independent of intrahepatic status. Even when a short period of calcitriol treatment do not reduce intestinal bacterial overgrowth, it induces a remarkable change of bacterial diversities and enrichment of Muribaculaceae, Bacteroidales, Allobaculum, Anaerovorax, and Ruminococcaceae.

CONCLUSION

Calcitriol treatment attenuates intestinal permeability, reduces bacterial translocation, and enriches potentially beneficial gut microbiota in cirrhotic rats that may enable it as a potential therapeutic agent to prevent cirrhotic complications.

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFLD.

Intestinal permeability in the pathogenesis of liver damage: From non-alcoholic fatty liver disease to liver transplantation

The intimate connection and the strict mutual cooperation between the gut and the liver realizes a functional entity called gut-liver axis. The integrity of intestinal barrier is crucial for the maintenance of liver homeostasis. In this mutual relationship, the liver acts as a second firewall towards potentially harmful substances translocated from the gut, and is, in turn, is implicated in the regulation of the barrier. Increasing evidence has highlighted the relevance of increased intestinal permeability and consequent bacterial translocation in the development of liver damage. In particular, in patients with non-alcoholic fatty liver disease recent hypotheses are considering intestinal permeability impairment, diet and gut dysbiosis as the primary pathogenic trigger. In advanced liver disease, intestinal permeability is enhanced by portal hypertension. The clinical consequence is an increased bacterial translocation that further worsens liver damage. Furthermore, this pathogenic mechanism is implicated in most of liver cirrhosis complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma. After liver transplantation, the decrease in portal pressure should determine beneficial effects on the gut-liver axis, although are incompletely understood data on the modifications of the intestinal permeability and gut microbiota composition are still lacking. How the modulation of the intestinal permeability could prevent the initiation and progression of liver disease is still an uncovered area, which deserves further attention.

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

INTRODUCTION AND AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Role of Oxygen Free Radicals, Nitric Oxide and Mitochondria in Mediating Cardiac Alterations During Liver Cirrhosis Induced by Thioacetamide

Thioacetamide (TAA) administration is widely used for induction of liver cirrhosis in rats, where reactive oxygen radicals (ROS) and nitric oxide (NO) participate in development of liver damage. Cardiac dysfunction is an important complication of liver cirrhosis, but the role of ROS or NO in cardiac abnormalities during liver cirrhosis is not well understood. This was investigated in animals after TAA-induced liver cirrhosis and temporal changes in oxidative stress, NO and mitochondrial function in the heart evaluated. TAA induced elevation in cardiac levels of nitrate before development of frank liver cirrhosis, without gross histological alterations. This was accompanied by an early induction of P38 MAP kinase, which is influenced by ROS and plays an important signaling role for induction of iNOS. Increased nitrotyrosine, protein oxidation and lipid peroxidation in the heart and cardiac mitochondria, suggestive of oxidative stress, also preceded frank liver cirrhosis. However, compromised cardiac mitochondrial function with a decrease in respiratory control ratio and increased mitochondrial swelling was seen later, when cirrhosis was evident. In conclusion, TAA induces elevations in ROS and NO in the heart in parallel to early liver damage. This leads to later development of functional deficits in cardiac mitochondria after development of liver cirrhosis.

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

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

Is intestinal oxidative stress involved in patients with compensated liver cirrhosis?

BACKGROUND

Liver cirrhosis is associated with intestinal epithelial barrier dysfunction, which may be affected by oxidative stress. Studies in cirrhotic rats provided evidence for intestinal oxidative stress, but studies in cirrhotic patients are scarce. We have shown intestinal barrier dysfunction in patients with compensated cirrhosis.

AIM

The present study aimed to investigate whether oxidative stress occurs in the intestinal mucosa of compensated cirrhotic patients and may contribute to barrier dysfunction.

MATERIAL AND METHODS

Oxidative stress was studied in duodenal and sigmoid biopsies from 15 cirrhotic patients and 22 controls by analyzing transcription of genes involved in glutathione and uric acid metabolism using quantitative real-time polymerase chain reaction. Protein levels of glutathione and glutathione disulphide were measured and the glutathione/glutathione disulphide ratio was calculated as marker of oxidative stress. In addition, intestinal myeloperoxidase and fecal calprotectin were determined.

RESULTS

Gene transcription of glutathione synthetase and glutathione reductase were significantly different in duodenal and sigmoid biopsies of cirrhotic patients vs. controls, but no alterations were found for other genes nor for glutathione, glutathione disulphide, glutathione/glutathione disulphide ratio and intestinal myeloperoxidase and fecal calprotectin concentrations.

CONCLUSION

This study did not find indications for oxidative stress and low-grade inflammation in the small and large intestine of stable compensated cirrhotic patients. Although these preliminary findings need further validation, we found intestinal oxidative stress not to be a major mechanism contributing to epithelial barrier dysfunction in patients with compensated cirrhosis.

Lipopolysaccharide-Induced Neutrophil Dysfunction Following Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS) Insertion is Associated with Organ Failure and Mortality

Systemic lipopolysaccharide (LPS) is implicated in increasing mortality in patients with alcoholic hepatitis but the underlying mechanisms are not well characterised. The objective of this study was to characterise neutrophil function, LPS and cytokine concentrations within the splanchnic circulation of alcoholic cirrhotic patients undergoing TIPSS insertion for variceal haemorrhage and correlate this with outcome. 26 patients with alcoholic cirrhosis and variceal haemorrhage were studied prior to and 1-hour after TIPSS insertion. Neutrophil function, LPS and cytokine concentrations were determined in arterial, hepatic venous (HV) and portal venous blood (PV). Significantly higher LPS concentrations and neutrophil reactive oxidant species (ROS) production were observed in PV vs HV blood. Cross-incubation of HV plasma with PV neutrophils resulted in reduced ROS production. Insertion of TIPSS was associated with a significant increase in arterial LPS concentrations and deterioration in neutrophil phagocytosis. Number of organ failures and arterial IL-6 concentrations at presentation were associated with increased mortality. The portal circulation has a distinct immunological milieu characterised by a pathological neutrophil phenotype and an anti-inflammatory cytokine profile associated with heightened LPS levels. TIPSS insertion renders this neutrophil functional defect systemic, associated with an increase in arterial LPS and a susceptibility to sepsis.

Intestinal permeability in a patient with liver cirrhosis

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

Age-dependent development of liver fibrosis in Glmp (gt/gt) mice

Background

Mice lacking glycosylated lysosomal membrane protein (Glmp^gt/gt mice) have liver fibrosis as the predominant phenotype due to chronic liver injury. The Glmp^gt/gt mice grow and reproduce at the same rate as their wild-type siblings. Life expectancy is around 18 months.

Methods

Wild-type and Glmp^gt/gt mice were studied between 1 week and 18 months of age. Livers were analyzed using histological, immunohistochemical, biochemical, and qPCR analyses.

Results

It was shown that Glmp^gt/gt mice were not born with liver injury; however, it appeared shortly after birth as indicated by excess collagen expression, deposition of fibrous collagen in the periportal areas, and increased levels of hydroxyproline in Glmp^gt/gt liver. Liver functional tests indicated a chronic, mild liver injury. Markers of inflammation, fibrosis, apoptosis, and modulation of extracellular matrix increased from an early age, peaking around 4 months of age and followed by attenuation of these signals. To compensate for loss of hepatocytes, the oval cell compartment was activated, with the highest activity of the oval cells detected at 3 months of age, suggesting insufficient hepatocyte proliferation in Glmp^gt/gt mice around this age. Although constant proliferation of hepatocytes and oval cells maintained adequate hepatic function in Glmp^gt/gt mice, it also resulted in a higher frequency of liver tumors in older animals.

Conclusions

The Glmp^gt/gt mouse is proposed as a model for slowly progressing liver fibrosis and possibly as a model for a yet undescribed human lysosomal disorder.

Electronic supplementary material

The online version of this article (doi:10.1186/s13069-016-0042-4) contains supplementary material, which is available to authorized users.

Beneficial effect of refined red palm oil on lipid peroxidation and monocyte tissue factor in HCV-related liver disease: a randomized controlled study

BACKGROUND

A large amount of endotoxin can be detected in the peripheral venous blood of patients with liver cirrhosis, contributing to the pathogenesis of hepatotoxicity because of its role in oxidative stress. The present study aimed to test the effect of the supplementation with red palm oil (RPO), which is a natural oil obtained from oil palm fruit (Elaeis guineensis) rich in natural fat-soluble tocopherols, tocotrienols and carotenoids, on lipid peroxidation and endotoxemia with plasma endotoxin-inactivating capacity, proinflammatory cytokines profile, and monocyte tissue factor in patients with chronic liver disease.

METHODS

The study group consisted of sixty patients (34 males and 26 females; mean age 62 years, range 54-75) with Child A/B, genotype 1 HCV-related cirrhosis without a history of ethanol consumption, randomly enrolled into an 8-week oral daily treatment with either vitamin E or RPO. All patients had undergone an upper gastrointestinal endoscopy 8 months before, and 13 out of them showed esophageal varices.

RESULTS

Both treatments significantly decreased erythrocyte malondialdehyde and urinary isoprostane output, only RPO significantly affected macrophage-colony stimulating factor and monocyte tissue factor. Liver ultrasound imaging did not show any change.

CONCLUSIONS

RPO beneficially modulates oxidative stress and, not least, downregulates macrophage/monocyte inflammatory parameters. RPO can be safely advised as a valuable nutritional implementation tool in the management of chronic liver diseases.

Role of microRNAs in Alcohol-Induced Multi-Organ Injury

Alcohol consumption and its abuse is a major health problem resulting in significant healthcare cost in the United States. Chronic alcoholism results in damage to most of the vital organs in the human body. Among the alcohol-induced injuries, alcoholic liver disease is one of the most prevalent in the United States. Remarkably, ethanol alters expression of a wide variety of microRNAs that can regulate alcohol-induced complications or dysfunctions. In this review, we will discuss the role of microRNAs in alcoholic pancreatitis, alcohol-induced liver damage, intestinal epithelial barrier dysfunction, and brain damage including altered hippocampus structure and function, and neuronal loss, alcoholic cardiomyopathy, and muscle damage. Further, we have reviewed the role of altered microRNAs in the circulation, teratogenic effects of alcohol, and during maternal or paternal alcohol consumption.

Sensitization to autoimmune hepatitis in group VIA calcium-independent phospholipase A2-null mice led to duodenal villous atrophy with apoptosis, goblet cell hyperplasia and leaked bile acids

Chronic bowel disease can co-exist with severe autoimmune hepatitis (AIH) in an absence of primary sclerosing cholangitis. Genetic background may contribute to this overlap syndrome. We previously have shown that the deficiency of iPLA2β causes an accumulation of hepatocyte apoptosis, and renders susceptibility for acute liver injury. We here tested whether AIH induction in iPLA2β-null mice could result in intestinal injury, and whether bile acid metabolism was altered. Control wild-type (WT) and female iPLA2β-null (iPLA2β(-/-)) mice were intravenously injected with 10mg/kg concanavalinA (ConA) or saline for 24h. ConA treatment of iPLA2β(-/-) mice caused massive liver injury with increased liver enzymes, fibrosis, and necrosis. While not affecting WT mice, ConA treatment of iPLA2β(-/-) mice caused severe duodenal villous atrophy concomitant with increased apoptosis, cell proliferation, globlet cell hyperplasia, and endotoxin leakage into portal vein indicating a disruption of intestinal barrier. With the greater extent than in WT mice, ConA treatment of iPLA2β(-/-) mice increased jejunal expression of innate response cytokines CD14, TNF-α, IL-6, and SOCS3 as well as chemokines CCL2 and the CCL3 receptor CCR5. iPLA2β deficiency in response to ConA-induced AIH caused a significant decrease in hepatic and biliary bile acids, and this was associated with suppression of hepatic Cyp7A1, Ntcp and ABCB11/Bsep and upregulation of intestinal FXR/FGF15 mRNA expression. The suppression of hepatic Ntcp expression together with the loss of intestinal barrier could account for the observed bile acid leakage into peripheral blood. Thus, enteropathy may result from acute AIH in a susceptible host such as iPLA2β deficiency.

Gastrointestinal dysfunction in autism spectrum disorder: the role of the mitochondria and the enteric microbiome

Autism spectrum disorder (ASD) affects a significant number of individuals worldwide with the prevalence continuing to grow. It is becoming clear that a large subgroup of individuals with ASD demonstrate abnormalities in mitochondrial function as well as gastrointestinal (GI) symptoms. Interestingly, GI disturbances are common in individuals with mitochondrial disorders and have been reported to be highly prevalent in individuals with co-occurring ASD and mitochondrial disease. The majority of individuals with ASD and mitochondrial disorders do not manifest a primary genetic mutation, raising the possibility that their mitochondrial disorder is acquired or, at least, results from a combination of genetic susceptibility interacting with a wide range of environmental triggers. Mitochondria are very sensitive to both endogenous and exogenous environmental stressors such as toxicants, iatrogenic medications, immune activation, and metabolic disturbances. Many of these same environmental stressors have been associated with ASD, suggesting that the mitochondria could be the biological link between environmental stressors and neurometabolic abnormalities associated with ASD. This paper reviews the possible links between GI abnormalities, mitochondria, and ASD. First, we review the link between GI symptoms and abnormalities in mitochondrial function. Second, we review the evidence supporting the notion that environmental stressors linked to ASD can also adversely affect both mitochondria and GI function. Third, we review the evidence that enteric bacteria that are overrepresented in children with ASD, particularly Clostridia spp., produce short-chain fatty acid metabolites that are potentially toxic to the mitochondria. We provide an example of this gut–brain connection by highlighting the propionic acid rodent model of ASD and the clinical evidence that supports this animal model. Lastly, we discuss the potential therapeutic approaches that could be helpful for GI symptoms in ASD and mitochondrial disorders. To this end, this review aims to help better understand the underlying pathophysiology associated with ASD that may be related to concurrent mitochondrial and GI dysfunction.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Long-term cannabinoid type 2 receptor agonist therapy decreases bacterial translocation in rats with cirrhosis and ascites

BACKGROUND & AIMS

Intestinal hyperpermeability, impaired peritoneal macrophages (PMs) phagocytosis, and bacterial translocation (BT), resulting in increased systemic and local infection/inflammation such as spontaneous bacterial peritonitis (SBP) together with increased tumor necrosis factor-α (TNFα) levels, are all implicated in the pathogenesis of cirrhosis-related complications. Manipulation of the cannabinoid receptors (CB1R and CB2R), which are expressed on the gut mucosa and PMs, has been reported to modulate intestinal inflammation and systemic inflammatory cytokine release. Our study aims to explore the effects of chronic CB1R/CB2R agonist/antagonist treatments on relevant abnormalities in cirrhotic ascitic rats.

METHODS

Vehicle, archidonyl-2-chloroethylamide (ACEA, CB1R agonist), JWH133 (CB2R agonist), and AM630 (CB2R antagonist) were given to thioacetamide (TAA) and common bile duct ligation (BDL) cirrhotic rats with ascites for two weeks and various measurement were performed.

RESULTS

Compared to sham rats, CB2Rs were downregulated in cirrhotic rat intestines and PMs. The two-week JWH133 treatment significantly decreased systemic/intestinal oxidative stress, TNFα and inflammatory mediators, infection, intestinal mucosal damage and hyperpermeability; the JWH133 treatment also decreased bacterial overgrowth/adhesion, BT and SBP, upregulated intestinal tight junctions and downregulated the PM TNFα receptor/NFκBp65 protein expression in cirrhotic rats. Acute and chronic JWH133 treatment corrected the TNFα-induced suppression of phagocytosis of cirrhotic rat PMs, which then could be reversed by concomitant AM630 treatment.

CONCLUSIONS

Our study suggests that CB2R agonists have the potential to treat BT and various relevant abnormalities through inhibition of systemic/intestinal oxidative stress, inflammatory cytokines and TNFα release in cirrhosis. Overall, the chronic CB2R agonist treatment affects multiple approach mechanisms, and its direct effect on the hyperdynamic circulation is only minor.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Alcoholic pancreatitis: A tale of spirits and bacteria

Alcohol is a major cause of chronic pancreatitis. About 5% of alcoholics will ever suffer from pancreatitis, suggesting that additional co-factors are required to trigger an overt disease. Experimental work has implicated lipopolysaccharide, from gut-derived bacteria, as a potential co-factor of alcoholic pancreatitis. This review discusses the effects of alcohol on the gut flora, the gut barrier, the liver-and the pancreas and proposes potential interventional strategies. A better understanding of the interaction between the gut, the liver and the pancreas may provide valuable insight into the pathophysiology of alcoholic pancreatitis.

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

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

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.

Probiotic as a novel treatment strategy against liver disease

CONTEXT

A symbiotic relationship between the liver and intestinal tract enables the healthy status of both organs. Microflora resident in intestinal lumen plays a significant role in hepatocytes function. Alterations to the type and amount of microorganisms that live in the intestinal tract can result in serious and harmful liver dysfunctions such as cirrhosis, nonalcoholic fatty liver disease, alcoholic liver disease, and hepatic encephalopathy. An increased number of pathogens, especially enterobacteriaceae, enterococci, and streptococci species causes the elevation of intestinal permeability and bacterial translocation. The presence of high levels of lipopolysaccharide (LPS) and bacterial substances in the blood result in a portal hypertension and ensuing hepatocytes damage. Several methods including the usage of antibiotics, prebiotics, and probiotics can be used to prevent the overgrowth of pathogens. Compared to prebiotic and antibiotic therapy, probiotics strains are a safer and less expensive therapy. Probiotics are "live microorganisms (according to the FAO/WHO) which when administered in adequate amounts confer a health benefit on the host".

EVIDENCE ACQUISITIONS

Data from numerous preclinical and clinical trials allows for control of the flora bacteria quantity, decreases in compounds derived from bacteria, and lowers proinflammatory production such as TNF-α, IL-6 and IFN-γ via down-regulation of the nuclear factor kappa B (NF-κ B).

RESULTS

On the other hand, probiotic can reduce the urease activity of bacterial microflora. Furthermore, probiotic decreases fecal pH value and reduces ammonia adsorption. In addition, the serum level of liver enzymes and other substances synthesized by the liver are modulated subsequent to probiotic consumption.

CONCLUSIONS

According to our knowledge, Probiotic therapy as a safe, inexpensive and a noninvasive strategy can reduce pathophysiological symptoms and improve different types of liver diseases without side effects.

Pathological bacterial translocation in cirrhosis: pathophysiology, diagnosis and clinical implications

Bacterial translocation (BT) is defined by the passage of viable indigenous bacteria from the intestinal lumen to mesenteric lymph nodes (MLNs) and other territories, and its diagnostic criteria rely on the isolation of viable bacteria in MLNs. Small intestinal overgrowth, increased intestinal permeability and immunological alterations are the main factors involved in its pathogenesis. BT is obviously difficult to identify in patients with cirrhosis, and alternative methods have been proposed instead. Bacterial DNA detection and species identification in serum or ascitic fluid has been proposed as a reliable marker of BT. Bacterial products, such as endotoxin, or bacterial DNA can translocate to extra-intestinal sites and promote an immunological response similar to that produced by viable bacteria. Therefore, pathological BT plays an important role in the pathogenesis of the complications of cirrhosis, not only in infections, but by exerting a profound inflammatory state and exacerbating the haemodynamic derangement. This may promote in turn the development of hepatorenal syndrome, hepatic encephalopathy and other portal hypertension-related complications. Therapeutic approaches for the prevention of BT in experimental and human cirrhosis are summarized. Finally, new investigations are needed to better understand the pathogenesis and consequences of translocation by viable bacteria (able to grow in culture), or non-viable BT (detection of bacterial fragments with negative culture) and open new therapeutic avenues in patients with cirrhosis.

The role of gut-liver axis in the pathogenesis of liver cirrhosis and portal hypertension

Because of the anatomical position and its unique vascular system, the liver is susceptible to the exposure to the microbial products from the gut. Although large amount of microbes colonize in the gut, translocation of the microbes or microbial products into the liver and systemic circulation is prevented by gut epithelial barrier function and cleansing and detoxifying functions of the liver in healthy subjects. However, when the intestinal barrier function is disrupted, large amount of bacterial products can enter into the liver and systemic circulation and induce inflammation through their receptors. Nowadays, there have been various reports suggesting the role of gut flora and bacterial translocation in the pathogenesis of chronic liver disease and portal hypertension. This review summarizes the current knowledge about bacterial translocation and its contribution to the pathogenesis of chronic liver diseases and portal hypertension.

Role of intestinal permeability and inflammation in the biological and behavioral control of alcohol-dependent subjects

BACKGROUND AND AIMS

Mood and cognition alterations play a role in the motivation for alcohol-drinking. Lipopolysaccharides are known to stimulate inflammation that was shown to induce mood and cognitive changes in rodents and humans. Enhanced intestinal permeability and elevated blood LPS characterize alcohol-dependent mice. However, no data have been published in non-cirrhotic humans. Our first goal was to test whether intestinal permeability, blood LPS and cytokines are increased in non-cirrhotic alcohol-dependent subjects before withdrawal and if they recover after withdrawal. Our second goal was to test correlations between these biochemical and the behavioral variables to explore the possibility of a role for a gut-brain interaction in the development of alcohol-dependence.

METHODS

Forty alcohol-dependent-subjects hospitalized for a 3-week detoxification program were tested at onset (T1) and end (T2) of withdrawal and compared for biological and behavioral markers with 16 healthy subjects. Participants were assessed for gut permeability, systemic inflammation (LPS, TNFα, IL-6, IL-10, hsCRP) and for depression, anxiety, alcohol-craving and selective attention.

RESULTS

Intestinal permeability and LPS were largely increased in alcohol-dependent subjects at T1 but recovered completely at T2. A low-grade inflammation was observed at T1 that partially decreased during withdrawal. At T1, pro-inflammatory cytokines were positively correlated with craving. At T2 however, the anti-inflammatory cytokine IL-10 was negatively correlated with depression, anxiety and craving.

CONCLUSION

Leaky gut and inflammation were observed in non-cirrhotic alcohol-dependent subjects and inflammation was correlated to depression and alcohol-craving. This suggests that the gut-brain axis may play a role in the pathogenesis of alcohol-dependence.

Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Rapid alternative absorption of dietary long-chain fatty acids with upregulation of intestinal glycosylated CD36 in liver cirrhosis

BACKGROUND

Dietary long-chain fatty acid (LCFA) intake is an important risk factor for hepatic inflammation and hepatocarcinogenesis. An alternate route of dietary LCFA absorption has been suggested in patients with liver cirrhosis (LC).

OBJECTIVE

We aimed to determine this alternate route and to identify its mechanism.

DESIGN

Twenty healthy control subjects and 47 patients with LC-n = 23 with portal hypertension [PH(+)LC] and 24 without portal hypertension [PH(-)LC)]-were enrolled. [¹³C]Palmitate (an LCFA) and octanoate (a medium-chain fatty acid [MCFA]) were administered by using gastrointestinal endoscopy. Breath ¹³CO₂ was measured to quantify metabolized fatty acids. We also examined intestinal specimens of patients in these groups.

RESULTS

A more rapid increase in metabolized palmitate, which showed a pattern similar to that of octanoate metabolism, was observed in patients with LC than in healthy control subjects. The increase in the PH(-)LC group was higher than that in the PH(+)LC group. However, the concentration of metabolized palmitate increased with treatment of the PH(+)LC group with a portal-systemic shunt. Morphologic changes such as expanded lymph and blood vessels were present, and glycosylated CD36 increased in the jejunum of the PH(+)LC group. This group had high serum concentrations of glucagon-like peptide-2. These data suggest that dietary LCFAs, similar to MCFAs, are absorbed via blood vessels in patients with LC.

CONCLUSIONS

Rapid absorption of LCFAs by an alternative method occurred in patients with LC. This altered LCFA processing is likely related to upregulation of intestinal glycosylated CD36 and could contribute to pathogenesis in patients with LC.

Altered intestinal tight junctions' expression in patients with liver cirrhosis: a pathogenetic mechanism of intestinal hyperpermeability

BACKGROUND

Increased intestinal permeability in cirrhosis exerts a pivotal role in the pathogenesis of spontaneous bacterial peritonitis and other complications of cirrhosis through promotion of systemic endotoxemia. This study was designed to investigate whether the expression of tight junction (TJ) proteins, which regulate gut paracellular permeability, is altered in the intestinal mucosa of patients with liver cirrhosis and study its potential association with the stage of liver disease and the development of systemic endotoxemia.

DESIGN

Twenty-four patients with cirrhosis at a decompensated (n = 12, group A) or compensated condition (n = 12, group B) and 12 healthy controls (group C) were subjected to duodenal biopsy. The expression of the TJ proteins occludin and claudin-1 in the intestinal epithelium was evaluated by immunohistochemistry. Plasma endotoxin concentrations were also determined.

RESULTS

Patients with cirrhosis presented significantly higher serum endotoxin concentrations as compared to healthy controls (P < 0·001), whilst endotoxemia was higher in decompensated disease (P < 0·05 vs. compensated cirrhosis). Patients with decompensated and compensated cirrhosis presented significantly reduced expression of occludin and claudin-1 as compared to controls (P < 0·01, respectively). These alterations were significantly more pronounced in decompensated patients as compared to compensated (P < 0·05). Regarding occludin, in patients with cirrhosis, a specific pattern of expression in the intestinal epithelium was observed, with a gradually increasing loss of expression from crypt to tip of the villi. Occludin and claudin-1 expression were inversely correlated with Child-Pugh score (P < 0·001), the grade of oesophageal varices (P < 0·01) and endotoxin concentrations (P < 0·001).

CONCLUSIONS

This study demonstrates for the first time that human liver cirrhosis induces significant alterations in enterocytes' TJs. These changes might represent an important cellular mechanism for intestinal barrier dysfunction and hyperpermeability in patients with liver cirrhosis.

Bench-to-beside review: acute-on-chronic liver failure - linking the gut, liver and systemic circulation

The concept of acute-on-chronic liver failure (ACLF) was introduced recently to describe a subset of patients with chronic liver disease presenting with profound deterioration of liver function and rapidly evolving multi-organ failure. ACLF is frequently accompanied by the development of severe inflammatory response syndrome and has a high mortality. To date, treatment options are limited and exclusively supportive. Over the last few years, some insights have been generated in the pathophysiology of ACLF. A key role for the interaction of innate immune dysfunction, enhanced bacterial translocation from the gut, and circulatory dysfunction has been proposed. In this respect, therapeutic strategies have been examined, with variable success, in experimental studies in animals and humans. This review focuses on potentially relevant pathophysiological elements in the development of ACLF and points out promising treatment modalities in ACLF.

Intestinal involvement during 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced chronic liver injury in a mouse model

PURPOSE

Although a physiologic relationship between intestinal mucosal integrity and hepatic function has been previously described, the effect of primary liver disease on intestinal mucosal homeostasis has not been previously well documented. In the current study, we studied the effects of chronic liver injury as a primary injury on enterocyte turnover (proliferation and apoptosis) in a mouse model.

METHODS

The liver toxin 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-enriched diet was used to induce chronic cholestatic liver injury in mice. Livers and intestine were harvested after 3 weeks of dietary treatment of histologic analysis and a determination of cell proliferation (immunohistochemistry for Ki67), or apoptosis (immunohistochemistry for caspase-3), as well as a determination of Wnt/β-catenin signaling activity.

RESULTS

All DDC-fed animals exhibited histologic evidence of liver damage that was associated with the expansion of atypical ductal proliferation near the periportal areas and increased oxidative stress. In the intestine, DDC-induced liver damage was associated with decreased villus height, decreased enterocyte proliferation, and increased cell apoptosis compared with control animals. There was also evidence for decreased β-catenin expression by immunostaining in crypt and villus cells of DDC-fed mice compared with control animals.

CONCLUSION

Primary liver injury and cholestasis is associated with intestinal mucosal hypoplasia. Decreased cell proliferation and increased cell apoptosis may be responsible for decreased intestinal epithelial cell mass. The observed decrease in cell turnover is accompanied by an alteration in Wnt/β-catenin signaling.

AST-120 (spherical carbon adsorbent) lowers ammonia levels and attenuates brain edema in bile duct-ligated rats

The pathogenesis of hepatic encephalopathy is multifactorial, involving gut-derived toxins such as ammonia, which has been demonstrated to induce oxidative stress. Therefore, a primary hepatic encephalopathy treatment target is reducing ammonia production in the gastrointestinal tract. AST-120, an oral adsorbent of engineered activated carbon microspheres with surface areas exceeding 1600 m2/g, acts as a sink for neurotoxins and hepatotoxins present in the gut. We evaluated the capacity of AST-120 to adsorb ammonia in vitro and to lower blood ammonia, oxidative stress and brain edema in cirrhotic rats. Cirrhosis was induced in rats by bile duct ligation for 6 weeks. AST-120 was administered by gavage preventively for 6 weeks (0.1, 1, and 4 g/kg/day). In addition, AST-120 was evaluated as a short-term treatment for 2 weeks and 3 days (1 g/kg/day) and as a sink to adsorb intravenously infused ammonium acetate. In vitro, AST-120 efficiently adsorbed ammonia. Ammonia levels significantly decreased in a dose-dependent manner for all AST-120-treated bile duct-ligated rats (nontreated: 177.3 ± 30.8 μM; AST-120, 0.1 g/kg/day: 121.9 ± 13.8 μM; AST-120, 1 g/kg/day: 80.9 ± 30.0 μM; AST-120, 4 g/kg/day: 48.8 ± 19.6 μM) and significantly correlated with doses of AST-120 (r = -0.6603). Brain water content and locomotor activity normalized after AST-120 treatments, whereas arterial reactive oxygen species levels remained unchanged. Furthermore, AST-120 significantly attenuated a rise in arterial ammonia after ammonium acetate administration (intravenously).

CONCLUSION

AST-120 treatment decreased arterial ammonia levels, normalized brain water content and locomotor activity but did not demonstrate an effect on systemic oxidative stress. Also, AST-120 acts as an ammonia sink, efficiently removing blood-derived ammonia. Additional studies are warranted to evaluate the effects of AST-120 on hepatic encephalopathy in patients with advanced liver disease.

Gut microbiota and probiotics in chronic liver diseases

There is a strong relationship between liver and gut: the portal system receives blood from the gut, and intestinal blood content activates liver functions. The liver, in turn, affects intestinal functions through bile secretion into the intestinal lumen. Alterations of intestinal microbiota seem to play an important role in induction and promotion of liver damage progression, in addition to direct injury resulting from different causal agents. Bacterial overgrowth, immune dysfunction, alteration of the luminal factors, and altered intestinal permeability are all involved in the pathogenesis of complications of liver cirrhosis, such as infections, hepatic encephalopathy, spontaneous bacterial peritonitis, and renal failure. Probiotics have been suggested as a useful integrative treatment of different types of chronic liver damage, for their ability to augment intestinal barrier function and prevent bacterial translocation. This review summarizes the main literature findings about the relationships between gut microbiota and chronic liver disease, both in the pathogenesis and in the treatment by probiotics of the liver damage.

Impaired glucose absorption in children with severe malnutrition

OBJECTIVE

To quantify intestinal glucose absorption in children with two types of severe malnutrition, kwashiorkor and marasmus, compared with healthy children.

STUDY DESIGN

Children with kwashiorkor (n = 6) and marasmus (n = 9) and control subjects (n = 3) received a primed (13 mg/kg), constant infusion (0.15 mg/kg/min) of [6,6H2]glucose for 4.5 hours. Two hours after start of the infusion an oral bolus of glucose 1.75 g/kg labeled with [U-13C]glucose 10 mg/g was given and was followed by periodic blood sampling. Mathematical modeling was applied to determine oral glucose absorption.

RESULTS

Median total glucose absorption was 5.9 mmol/kg, interquartile range (IQR) 4.5-6.7 mmol/kg and 4.4 (IQR 2.9-5.9) mmol/kg in children with kwashiorkor and marasmus compared with 7.7 (IQR 5.8-9.0) mmol/kg in control subjects; P = .03 compared with marasmus). Children with the lowest glucose absorption were found specifically in the kwashiorkor group and marasmic children with hypoalbuminemia. Severe impairment in absorption correlated with urinary 8-hydroxydeoxyguanosine secretion (r = -0.62, P = .01).

CONCLUSIONS

Severe malnutrition is associated with an impaired glucose absorption and decreased glucose absorption correlates with oxidative stress in these children.

Intestinal permeability assessed by 51Cr-EDTA in rats with CCl4 - induced cirrhosis

CONTEXT

The straight relationship between cirrhosis and impaired intestinal barrier has not been elucidated yet.

OBJECTIVES

To verify (51)Cr-EDTA-intestinal permeability in rats with CCl(4)-induced cirrhosis and controls.

METHOD

Fifty male Wistar rats weighing 150-180 g were separated in three groups: 25 animals received CCl(4) 0.25 mL/kg with olive oil by gavage with 12 g/rat/day food restriction for 10 weeks (CCl(4)-induced cirrhosis); 12 received the same food restriction for 10 weeks (CCl(4)-non exposed). Other 13 rats received indomethacin 15 mg/kg by gavage as positive control of intestinal inflammation.

RESULTS

The median (25-75 interquartile range) (51)Cr-EDTA-IP values of cirrhotic and CCl(4)-non exposed rats were 0.90% (0.63-1.79) and 0.90% (0.60-1.52) respectively, without significant difference (P = 0.65). Animals from indomethacin group showed (51)Cr-EDTA-IP, median 7.3% (5.1-14.7), significantly higher than cirrhotic and CCl(4)-non exposed rats (P<0.001).

CONCLUSION

This study showed the lack of difference between (51)Cr-EDTA-intestinal permeability in rats with and without cirrhosis. Further studies are necessary to better clarify the relationship between intestinal permeability and cirrhosis.

Increased plasma malondialdehyde in patients with viral cirrhosis and its relationships to plasma nitric oxide, endotoxin, and portal pressure

BACKGROUND AND AIM

Increased oxidative stress is involved in the development of portal hypertension in cirrhosis. Our study aimed to assess the relationship between oxidative stress and hemodynamic parameters in cirrhotic patients.

METHODS

Forty-two patients with viral cirrhosis and 24 normal controls were enrolled. Measurements of plasma levels of malondialdehyde (MDA), nitrite/nitrate (NOx), endotoxin, and activities of superoxide dismutase (SOD) were carried out in all subjects. Systemic and splanchnic hemodynamic measurements were carried out in cirrhotic patients.

RESULTS

Plasma levels of MDA, endotoxin, and NOx were significantly higher in cirrhotic patients than in normal controls (900 +/- 751 versus 226 +/- 16 nM, P < 0.01; 62.0 +/- 26.0 versus 14.8 +/- 4.1 pg/mL, P < 0.01; 50.5 +/- 22.6 versus 15.0 +/- 9.2 nM, P < 0.01, respectively). Activities of SOD were significantly decreased in cirrhotic patients compared with in normal controls (2.62 +/- 0.7 versus 6.8 +/- 0.4 U/mL). Further, plasma levels of MDA in cirrhotic patients were significantly positively associated with hepatic venous pressure gradient (HVPG) (r = 0.35; P = 0.025), wedge hepatic venous pressure (WHVP) (r = 0.42; P = 0.007), and hepatic sinusoid resistance (HSR) (r = 0.33; P = 0.033). Plasma MDA levels also correlated positively with plasma endotoxin (r = 0.71, P < 0.001) and NOx (r = 0.55, P < 0.001) levels in the cirrhotic patients. Multiregression analysis showed that the independent and strongest factors to predict HVPG, WHVP, and HSR are plasma levels of NOx, MDA, and endotoxin, respectively.

CONCLUSION

This study suggests a close interaction among MDA, endotoxin, and NOx and that these substances are also associated with hemodynamic derangement in cirrhosis.