Allopurinol and glutamine attenuate bacterial translocation in chronic portal hypertensive and common bile duct ligated growing rats

Lipid peroxidation and liver damage in double and simple common bile duct ligation models in male Sprague-Dawley rats

AIMS

Bacterial translocation, defined as the presence of living bacteria or bacterial fragments in both mesenteric lymph nodes or systemic circulation, can cause a severe inflammatory reaction in patients with cirrhosis. This study aimed to compare lipid peroxidation associated with liver damage in different experimental models of bile duct ligation: proximal double ligation and transection versus proximal simple ligation versus sham.

MATERIALS AND METHODS

Sixty-two male rats underwent one of three bile duct surgical interventions: proximal double ligation and transection (n = 22); proximal simple ligation (n = 19); or sham operation (n = 21). We performed microbiological culture of mesenteric lymph nodes; portal and cava blood, spleen and liver cultures; and histological analysis of liver parenchyma. Samples of blood and liver were obtained at laparotomy for malondialdehyde quantification.

KEY FINDINGS

Serum malondialdehyde levels were significantly higher in simple ligature animals (3.7 nmol/mg, standard deviation [SD] 2.1) compared to controls (1.6 nmol/mg SD 0.5; p = 0.001) or double ligature (0.3 nmol/mg SD 0.3; p = 0.001). Liver malondialdehyde levels were significantly higher in animals subjected to double ligation vs controls (9.0 nmol/mg SD 2.8 vs. 1.7 nmol/mg SD 1.0; p = 0.0007) and simple ligature (2.9 nmol/mg SD 2.0; p = 0.0001). Overall incidence of bacterial translocation was similar in simple and double ligatures (22.2 % and 21 % respectively), and significantly higher than in controls.

SIGNIFICANCE

the type of bile duct ligation influences the type and localization of lipid peroxidation, but does not influence the development of bacterial translocation.

Hepatic encephalopathy: investigational drugs in preclinical and early phase development

INTRODUCTION

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome, in patients with liver disease, which affects life quality and span. Current treatments are lactulose or rifaximin, acting on gut microbiota. Treatments aiming ammonia levels reduction have been tested with little success.

AREAS COVERED

Pre-clinical research shows that the process inducing HE involves sequentially: liver failure, altered microbiome, hyperammonemia, peripheral inflammation, changes in immunophenotype and extracellular vesicles and neuroinflammation, which alters neurotransmission impairing cognitive and motor function. HE may be reversed using drugs acting at any step: modulating microbiota with probiotics or fecal transplantation; reducing peripheral inflammation with anti-TNFα, autotaxin inhibitors or silymarin; reducing neuroinflammation with sulforaphane, p38 MAP kinase or phosphodiesteras 5 inhibitors, antagonists of sphingosine-1-phosphate receptor 2, enhancing meningeal lymphatic drainage or with extracellular vesicles from mesenchymal stem cells; reducing GABAergic neurotransmission with indomethacin or golexanolone.

EXPERT OPINION

A factor limiting the progress of HE treatment is the lack of translation of research advances into clinical trials. Only drugs acting on microbiota or ammonia reduction have been tested in patients. It is urgent to change the mentality on how to approach HE treatment to develop clinical trials to assess drugs acting on the immune system/peripheral inflammation, neuroinflammation or neurotransmission to improve HE.

The association of dietary glutamine supplementation with the development of high salt-induced hypertension in rats

Glutamine supplementation has been reported to affect blood pressure (BP). However, its role in the progression of hypertension induced by high salt diet (HSD) has not been elucidated. Male normotensive Wistar rats were exposed to high salt diet and treated with different doses of glutamine supplementation. Rats aged 6 weeks were assigned to five groups: (1) Normal-salt diet (0.3% NaCl, NSD); (2) High-salt diet (8% NaCl, HSD); (3) High-salt + low-dose diet (8% NaCl, 0.5 g of L-glutamine/kg body weight, HSLGD); (4) High-salt + middle-dose diet (8% NaCl, 1.5 g of L-glutamine/kg body weight, HSMGD); and (5) High-salt + high-dose diet (8% NaCl, 2.5 g of L-glutamine/kg body weight, HSHGD). After supplementing different doses of glutamine to male Wistar 6-week-old rats fed with HSD for 7 weeks, we found no difference in body weight among groups. Importantly, we showed that dietary L-glutamine supplementation could prevent the development of hypertension in a dose-dependent manner [dramatically lowering systolic blood pressure (SBP) and slightly reducing diastolic blood pressure (DBP) of hypertensive rats, while the differences of DBP between groups did not reach statistical significance]. Our data further elucidated that dietary glutamine supplementation mildly alleviated the degree of left ventricular hypertrophy, including interventricular septal thickness (IVST) and left ventricular posterior wall thickness (LVPWT) in hypertensive rats. Together, our results offer evidence that the dietary uptake of glutamine may be associated with attenuating the development of high salt-induced hypertension and slightly alleviating the degree of left ventricular hypertrophy in hypertensive rats. Therefore, glutamine supplementation may act as a prospective dietary intervention for the treatment of hypertension.

The effects of rhein on D-GalN/LPS-induced acute liver injury in mice: Results from gut microbiome-metabolomics and host transcriptome analysis

Background

Rhubarb is an important traditional Chinese medicine, and rhein is one of its most important active ingredients. Studies have found that rhein can improve ulcerative colitis by regulating gut microbes, but there are few reports on its effects on liver diseases. Therefore, this study aims to investigate these effects and underlying mechanisms.

Methods

Mice were given rhein (100 mg/kg), with both a normal control group and a model group receiving the same amount of normal saline for one week. Acute liver injury was induced in mice by intraperitoneal injection of D-GalN (800 mg/kg)/LPS (10 ug/kg). Samples (blood, liver, and stool) were then collected and assessed for histological lesions and used for 16S rRNA gene sequencing, high-performance liquid chromatography-mass spectrometry (LC-MS) and RNA-seq analysis.

Results

The levels of ALT and AST in the Model group were abnormal higher compared to the normal control group, and the levels of ALT and AST were significantly relieved in the rhein group. Hepatic HE staining showed that the degree of liver injury in the rhein group was lighter than that in the model group, and microbiological results showed that norank_o:Clostridia_UCG-014, Lachnoclostridium, and Roseburia were more abundant in the model group compared to the normal control group. Notably, the rhein treatment group showed reshaped disturbance of intestinal microbial community by D-GalN/LPS and these mice also had higher levels of Verrucomicrobia, Akkermansiaceae and Bacteroidetes. Additionally, There were multiple metabolites that were significantly different between the normal control group and the model group, such as L-α-amino acid, ofloxacin-N-oxide, 1-hydroxy-1,3-diphenylpropan-2-one,and L-4-hydroxyglutamate semialdehyde, but that returned to normal levels after rhein treatment. The gene expression level in the model group also changed significantly, various genes such as Cxcl2, S100a9, Tnf, Ereg, and IL-10 were up-regulated, while Mfsd2a and Bhlhe41 were down-regulated, which were recovered after rhein treatment.

Conclusion

Overall, our results show that rhein alleviated D-GalN/LPS-induced acute liver injury in mice. It may help modulate gut microbiota in mice, thereby changing metabolism in the intestine. Meanwhile, rhein also may help regulate genes expression level to alleviate D-GalN/LPS-induced acute liver injury.

Hepatic microcirculation and mechanisms of portal hypertension

The liver microcirculatory milieu, mainly composed of liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs) and hepatic macrophages, has an essential role in liver homeostasis, including in preserving hepatocyte function, regulating the vascular tone and controlling inflammation. Liver microcirculatory dysfunction is one of the key mechanisms that promotes the progression of chronic liver disease (also termed cirrhosis) and the development of its major clinical complication, portal hypertension. In the present Review, we describe the current knowledge of liver microcirculatory dysfunction in cirrhotic portal hypertension and appraise the preclinical models used to study the liver circulation. We also provide a comprehensive summary of the promising therapeutic options to target the liver microvasculature in cirrhosis.

Single versus double experimental bile duct ligation model for inducing bacterial translocation

BACKGROUND

Double common bile duct ligation plus section in rats is used as a model for bacterial translocation, a phenomenon that has been correlated with the degree of liver damage. This study analyzes whether a simpler variant of the technique is also a valid model to study bacterial translocation.

METHODS

Fifty-six male Sprague Dawley rats underwent one of three surgical interventions: a) proximal double ligation and section of the common bile duct; b) proximal simple ligation of the bile duct; and c) sham operation. Bacterial translocation was measured by cultures of mesenteric lymph nodes, blood, spleen and liver. Stool culture and histological analysis of liver damage were also performed.

RESULTS

The incidence of bacterial translocation in SBL and DBDL groups was 23,5% and 25% respectively. Mortality was similar between ligation groups (11.2% versus 10%). Liver cirrhosis developed in the group of double ligation and section (100% of the animals at 4 weeks), while portal hypertension appeared starting at week 3. None of the animals submitted to simple ligation developed liver cirrhosis.

CONCLUSIONS

Simple bile duct ligation is associated with a similar incidence of bacterial translocation as double ligation, but without cirrhosis or portal hypertension.

Glutamine prevents oxidative stress in a model of portal hypertension

AIM

To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL).

METHODS

Male Wistar rats were housed in a controlled environment and were allowed access to food and water ad libitum. Twenty-four male Wistar rats were divided into four experimental groups: (1) control group (SO) - rats underwent exploratory laparotomy; (2) control + glutamine group (SO + G) - rats were subjected to laparotomy and were treated intraperitoneally with glutamine; (3) portal hypertension group (PPVL) - rats were subjected to PPVL; and (4) PPVL + glutamine group (PPVL + G) - rats were treated intraperitoneally with glutamine for seven days. Local injuries were determined by evaluating intestinal segments for oxidative stress using lipid peroxidation and the activities of glutathione peroxidase (GPx), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) after PPVL.

RESULTS

Lipid peroxidation of the membrane was increased in the animals subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL procedure showed levels of lipid peroxidation similar to those of the control groups (P > 0.05). The activity of the antioxidant enzyme GTx was decreased in the gut of animals subjected to PH compared with that in the control group of animals not subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL showed similar GTx activity to both the control groups not subjected to PH (P > 0.05). At least 10 random, non-overlapping images of each histological slide with 200 × magnification (44 pixel = 1 μm) were captured. The sum means of all areas, of each group were calculated. The mean areas of eNOS staining for both of the control groups were similar. The PPVL group showed the largest area of staining for eNOS. The PPVL + G group had the second highest amount of staining, but the mean value was much lower than that of the PPVL group (P < 0.01). For iNOS, the control (SO) and control + G (SO + G) groups showed similar areas of staining. The PPVL group contained the largest area of iNOS staining, followed by the PPVL + G group; however, this area was significantly smaller than that of the group that underwent PH without glutamine (P < 0.01).

CONCLUSION

Treatment with glutamine prevents gut mucosal injury after PH in rats.

Glutamine-Induced Secretion of Intestinal Secretory Immunoglobulin A: A Mechanistic Perspective

Secretory immunoglobulin A (SIgA) is one important line of defense in the intestinal mucosal surface to protect the intestinal epithelium from enteric toxins and pathogenic microorganisms. Multiple factors, such as intestinal microbiota, intestinal cytokines, and nutrients are highly involved in production of SIgA in the intestine. Recently, glutamine has been shown to affect intestinal SIgA production; however, the underlying mechanism by which glutamine stimulates secretion of intestinal SIgA is unknown. Here, we review current knowledge regarding glutamine in intestinal immunity and show that glutamine-enhanced secretion of SIgA in the intestine may involve intestinal microbiota, intestinal antigen sampling and presentation, induction pathways for SIgA production by plasma cells (both T-dependent and T-independent pathway), and even transport of SIgA. Altogether, the glutamine-intestinal SIgA axis has broad therapeutic implications for intestinal SIgA-associated diseases, such as celiac disease, allergies, and inflammatory bowel disease.

Protective Effects of Curcumin on Intestinal Damage in Cholestatic Rats

BACKGROUND

The aim of this study was to evaluate the possible protective effects of curcumin on oxidative stress, cell proliferation, and apoptosis in the rat intestinal mucosa after bile duct ligation (BDL).

METHODS

A total of 18 male Sprague Dawley rats were divided into three groups: sham control, BDL and BDL+curcumin; each group contain six animals. The rats in the curcumin-treated group were given curcumin (100 mg/kg) once a day orally for 14 days, starting 3 days prior to BDL operation. Following 14 days of treatment, all the animals were decapitated and intestinal tissues samples obtained for biochemical and histopathological investigation.

RESULTS

Curcumin treatment was found to significantly lower elevated tissue malondialdehyde levels and myeloperoxidase activity, and to raise reduced glutathione levels in intestinal tissues samples. BDL caused severe histopathological injury, including shortening of the villi, loss of villous epithelium, multiple erosions, inflammatory cell infiltration, necrosis, and hemorrhage into the intestinal wall. Curcumin treatment significantly attenuated the severity of intestinal injury, with inhibition of BDL-induced apoptosis and cell proliferation.

CONCLUSION

Curcumin treatment has a protective effect against intestinal damage induced by BDL. The ability of curcumin treatment is to inhibit BDL-induced oxidative stress, apoptosis, and cell proliferation.

Effect of glutamine enriched nutrition support on gut barrier of rats with obstructive jaundice: A Meta-analysis

AIM: To systematically assess the effect of glutamine enriched enteral nutrition support on the gut barrier of rats with obstructive jaundice (OJ).

METHODS: Databases including PubMed, Embase, High Wire and Cochrane Central Register of Controlled Trials were searched using keywords "glutamine", "obstructive jaundice". Literature published before November 2014 was searched. Randomized controlled trials comparing conventional treatment and glutamine enriched nutrition support were enrolled in the study, and then the literature was screened and the data were extracted by two independent reviewers. The quality of the literature was assessed, and the data were analyzed using the RevMan4.2 software. Count data were analyzed using relative risk (RR) and 95% confidence interval (95%CI), and measurement data were analyzed using standard mean difference (SMD) or weighted mean difference (WMD) and 95%CI. The heterogeneity of the data was analyzed using the I² test.

RESULTS: Eight articles including 152 cases were enrolled in the study, and all of them were prospective randomized controlled studies. There were 76 rats treated by conventional methods (control group) and 76 rats receiving glutamine enriched nutrition support (experimental group). Compared with the control group, glutamine enriched nutrition support could decrease the rates of bacterial translocation (BT) to mesenteric lymph nodes (MLNs), the liver, spleen and blood (RR = 0.34, 0.36, 0.38, 0.30, P < 0.05), and enhance the antioxidant capacity of the intestinal mucosa (WMD_MPO = -0.44, WMD_MDA = -57.87; 95%CI: -0.85--0.03, -104.14--11.60; P < 0.05), but could not significantly improve the liver dysfunction and intestinal villi.

CONCLUSION: Glutamine enriched nutrition support has a protective effect on intestinal barrier function in rats with OJ in terms of reducing BT effectively and enhancing the antioxidant capacity of the intestinal mucosa significantly.

Effect of probiotic supplementation on bacterial translocation in common bile duct obstruction

OBJECTIVE

To investigate the effects of probiotics on bacterial translocation in the obstructive common bile duct with comparison to an enteral product containing arginine and glutamine.

MATERIAL AND METHOD

In our study, 40 Sprague-Dawley rats each weighing 250-300 g were used. Animals in Group 1 (sham) were laparatomized and fed standard chow supplemented with physiologic saline at daily doses of 2 ml through orogastric tube for 7 days. Common bile ducts of the animals in the other groups were ligated with 3/0 silk sutures. Group 2 (control group) was fed standard chow supplemented with daily doses of 2 ml physiologic saline. Group 3 (probiotic group) was fed standard chow supplemented with a probiotic solution (Acidophilus plus) containing strains of Lactobacillus acidophilus, Bifidobacterium bifidum and Lactobacillus bulgaricus at a daily doses of 2 × 10(9) colony forming units (CFU). Group 4 (formula group) was fed only an enteral solution (Stresson Multi Fiber) containing glutamine, arginine and a medium-chain fatty acid at daily doses of 2 g/kg. At the end of the 7th day, all animals were relaparatomized, and to determine bacterial translocation, aerobic, and anaerobic cultures were obtained from the specimens of mesenteric lymph nodes, intestinal mucosa, and blood samples. Smear cultures prepared from caecum were examined to determine the number of CFU. Finally, for histological examination specimens were excised from terminal ileum, and oxidative damage was assessed in liver tissues. Afterwards all animals were killed.

RESULTS

Moderately lesser degrees of bacterial translocation, and mucosal damage were seen in Groups 3, and 4 relative to Group 2 (p < 0.05). In Group 4, any difference was not seen in the number of cecal bacteria relative to baseline values, while in Group 3, significant decrease in cecal colonization was seen. Among all groups, a significant difference between levels of malondialdehyde, and glutathione was not observed.

CONCLUSION

At the end of our study, we have concluded that both probiotics, and enteral diets which contain immunomodulators such as glutamine, and arginine alleviate bacterial translocation, and impairment of intestinal mucosa.

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.

Effect of melatonin and misoprostol on bacterial translocation in portal hypertensive rats

BACKGROUND AND AIM

Portal hypertension is the main complication of cirrhosis and it is responsible for its most common complications. Bacterial translocation increases the morbidity and mortality rates in patients with portal hypertension. We aimed to investigate the effects of melatonin and misoprostol on bacterial translocation induced by portal hypertension.

METHODS

We established four groups, each containing eight rats. Except for the control and sham groups, the animals in the other groups (treatment groups) received misoprostol or melatonin for 3 days after the first operation. In the sham group, a laparotomy was carried out and only the portal vein was dissected. Calibrated portal vein ligation was carried out in the other groups. All animals were given 10(10) Escherichia coli by orogastric intubation 12 h before sampling. Seventy-two hours after the first operation, mesenteric lymph node and blood samples were obtained and cultured. Two cc blood samples were obtained for a polymerase chain reaction study. A piece of terminal ileum was also sampled for histopathologic examination.

RESULTS

Mesenteric lymph node and blood cultures of all control animals were positive for microbiological growth, and polymerase chain reaction results were positive in seven of the eight rats. Histopathologically, edema, vasodilatation and inflammatory cell infiltration were found to be less in the other groups in comparison to the control group. The incidence of bacterial translocation was decreased in all treatment groups as compared to the control group.

CONCLUSIONS

In this study, bacterial translocation occurred in portal hypertension. Melatonin and misoprostol reduced the incidence of bacterial translocation in portal hypertensive rats.

Bacterial translocation to mesenteric lymph nodes increases in chronic portal hypertensive rats

PURPOSE

Bacterial translocation is a frequent complication in portal hypertension related to cirrhosis in the human clinical area. The aim of this study was to verify the existence of intestinal bacterial translocation to mesenteric lymph nodes in male Wistar rats with triple partial portal vein ligation during short- (48 h) and long-term (1 month) postoperative evolution.

RESULTS

At 48 h, ileal total aerobes bacteria (p < 0.001) and Lactobacillus decrease in sham-operated (SO) and portal hypertensive (PH) rats. At 1 month, ileal Enterococci and Streptococcus sp. show a statistically significant decrease in SO- and PH-rats. Lactobacillus decreases in the colon in SO- (p < 0.01) and in PH-rats (p < 0.001). At 1 month, colonic Enterococci decreases compared to control (p < 0.001) and SO-rats (p < 0.01). These intestinal microfloral changes are associated with bacterial translocation to mesenteric lymph nodes at 48 h (50%; p = 0.004) and 1 month (100%; p < 0.001) of postoperative evolution in PH-rats.

CONCLUSIONS

The enlargement of the stenosed portal tract related to triple partial portal vein ligation in the rat, since it increases the resistance to the portal blood flow, may be a key factor involved in one of the pathological consequences of portal hypertension, as is bacterial translocation to mesenteric lymph nodes.

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.

Different clinical characteristics between polymicrobial and monomicrobial Aeromonas bacteremia--a study of 216 cases

BACKGROUND

Part of Aeromonas bacteremia is polymicrobial infection. However, a clinical comparison of monomicrobial and polymicrobial Aeromonas bacteremia has not hitherto been reported.

METHODS

A retrospective analysis of medical records of patients with Aeromonas bacteremia at three large referral hospitals in Taiwan for an 8-year period (2001-2008) was conducted.

RESULTS

There were 154 patients with monomicrobial Aeromonas bacteremia and 62 patients with polymicrobial Aeromonas bacteremia. In the polymicrobial infections, E. coli was the most common combined pathogen (42%), followed by Klebsiella spp. (24%) and Enterobacter spp. (16%). Multivariate logistic regression analysis revealed solid cancer as the risk factor for polymicrobial Aeromonas bacteremia, with male gender and cirrhosis as risk factors for monomicrobial Aeromonas bacteremia. However, of all types of solid cancer, hepatoma was associated with monomicrobial Aeromonas bacteremia. APACHE II score was the most important prognostic factor in both groups.

CONCLUSION

Aeromonas bacteremia in patients with cirrhosis or male gender tended to be monomicrobial. Polymicrobial Aeromonas bacteremia was associated with solid cancers. In either polymicrobial or monomicrobial Aeromonas bacteremia, prognosis could be predicted according to disease severity measured by APACHE II score.

Allopurinol to prevent pancreatitis after endoscopic retrograde cholangiopancreatography: a randomized placebo-controlled trial

BACKGROUND & AIMS

Endoscopic retrograde cholangiopancreatography (ERCP) is associated with a risk of pancreatitis (PEP). Animal studies suggest that (single-dose) allopurinol (xanthine oxidase inhibitor with high oral bioavailability and long-lasting active metabolites) may reduce this risk; human study results are conflicting. The aim of this study was to determine if allopurinol decreases the rate of PEP.

METHODS

Patients referred for ERCP to 9 endoscopists at 2 tertiary centers were randomized to receive either allopurinol 300 mg or identical placebo orally 60 minutes before ERCP, stratified according to high-risk ERCP (manometry or pancreatic therapy). The primary outcome (PEP) was adjudicated blindly; pancreatitis was defined according to the Cotton consensus, and evaluated at 48 hours and 30 days. Secondary outcomes included severe PEP, length of stay, and mortality (nil). The trial was terminated after the blinded (midpoint) interim analysis, as recommended by the independent data and safety monitoring committee.

RESULTS

We randomized 586 subjects, 293 to each arm. The crude PEP rates were 5.5% (allopurinol) and 4.1% (placebo), (P = .44; difference = 1.4%; 95% confidence interval, -2.1% to 4.8%). The Mantel-Haenszel combined risk ratio for PEP with allopurinol, considering stratification, was 1.37 (95% confidence interval, 0.65-2.86). Subgroup analyses suggested nonsignificant trends toward possible benefit in the high-risk group, and possible harm for the remaining subjects. Logistic regression found pancreatic therapy, pancreatic injection, and prior PEP to be the only independent predictors of PEP.

CONCLUSIONS

Allopurinol does not appear to reduce the overall risk of PEP; however, its potential benefit in the high-risk group (but potential harm for non-high-risk patients) means further study is required.

Plasma redox status is impaired in the portacaval shunted rat--the risk of the reduced antioxidant ability

Background

Portacaval shunting in rats produces a reduction of hepatic oxidant scavenging ability. Since this imbalance in hepatic oxidant/antioxidant homeostasis could coexist with systemic changes of oxidant stress/antioxidant status, plasma oxidants and antioxidant redox status in plasma of portacaval shunted-rats were determined.

Results

Male Wistar male: Control (n = 11) and with portacaval shunt (PCS; n = 11) were used. Plasma levels of the oxidant serum advanced oxidation protein products (AOPP), lipid hydroperoxides (LOOH), the antioxidant total thiol (GSH) and total antioxidant status (TAX) were measured. Albumin, ammonia, Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), thiostatin and alpha-1-acid glycoprotein (α₁-AGP) were also assayed 4 weeks after the operation. AOPPs were significantly higher (50.51 ± 17.87 vs. 36.25 ± 7.21 μM; p = 0.02) and TAX was significantly lower (0.65 ± 0.03 vs. 0.73 ± 0.06 mM; p = 0.007) in PCS compared to control rats. Also, there was hypoalbuminemia (2.54 ± 0.08 vs. 2.89 ± 0.18 g/dl; p = 0.0001) and hyperammonemia (274.00 ± 92.25 vs. 104.00 ± 48.05 μM; p = 0.0001) and an increase of thiostatin (0.23 ± 0.04 vs. 0.09 ± 0.01 mg/ml; p = 0.001) in rats with a portacaval shunt. The serum concentration of ammonia is correlated with albumin levels (r = 0.624; p = 0.04) and TAX correlates with liver weight (r = 0.729; p = 0.017) and albumin levels (r = 0.79; p = 0.007)

Conclusion

These findings suggest that in rats with a portacaval shunt a systemic reduction of oxidant scavenging ability, correlated with hyperammonemia, is principally produced. It could be hypothesized, therefore, that the reduced antioxidant defences would mediate a systemic inflammation.

Allopurinol, oxidative stress and intestinal permeability in patients with cirrhosis: an open-label pilot study

BACKGROUND

Cirrhosis is associated with intestinal barrier failure, related in part to enterocytes oxidative damage via xanthine oxidase overactivity. Experimentally, allopurinol, a xanthine oxidase inhibitor, reduces enterocytes' damage and bacterial translocation.

AIM

To assess the short-term effects of allopurinol on intestinal permeability, oxidative stress and endotoxin-dependent cytokines in patients with cirrhosis.

METHODS

Nineteen patients with cirrhosis, in a stable condition (age: 56 years; Child A/B/C: 6/7/6; ascites: 12; alcoholic cirrhosis: 16/19; abstinence >2 weeks), were included. At baseline and day 10 of allopurinol 400 mg/day, intestinal permeability [lactulose/mannitol (Lac/Man) ratio test], oxidative stress (serum malondialdehyde), as well as TNF-soluble receptor-1, IL-6 and lipopolysaccharide-binding protein (which reflects exposition to endotoxin) were measured.

RESULTS

Malondialdehyde decreased significantly (-23%, P<0.05), whereas no effects were seen on intestinal permeability and the endotoxin-associated systemic inflammatory response. At baseline, portal pressure correlated to the Lac/Man ratio (r=0.55, P<0.02). At day 10, changes in malondialdehyde correlated to changes in the Lac/Man ratio (r=0.51, P<0.05).

CONCLUSIONS

A 10-day course of allopurinol in patients with cirrhosis is associated with a significant reduction in oxidative stress but no effect on intestinal permeability and inflammatory markers. Whether intestinal damage in cirrhosis can be accessible to antioxidant therapy requires further study.

[Chronic inflammatory portal hypertensive enteropathy in the rat]

INTRODUCTION

Experimental portal hypertensive enteropathy could have an inflammatory etiopathogenesis and, if so, it would produce intestinal remodeling. The aim of this study was to test this hypothesis.

MATERIAL AND METHOD

Male Wistar rats with portal hypertension (PHT) produced by partial portal vein ligation were divided into four groups: group I (control; n = 9), group II (PHT; n = 8) at 3 months after surgery, group III (control; n = 8), and group IV (PHT; n = 10) at 1 year after surgery. The density of duodenal goblet cells and ileal levels of tumor necrosis factor (TNF)alpha, interleukin (IL)-1beta, and IL-10 were studied using an ELISA method.

RESULTS

At 3 months after surgery, rats with PHT showed an increase in the number of goblet cells in the small bowel (103.63 +/- 14.37 vs 99.42 +/- 19.19/1,000 microm2). This change was associated with an increase (p < 0.05) in ileal levels of TNFalpha (0.20 +/- 0.09 vs 0.08 +/- 0.02 pmol/mg protein), and IL-1beta (0.40 +/- 0.21 vs 0.19 +/- 0.09 pmol/mg protein), as well as with a decrease (p < 0.05) in ileal IL-10 levels (0.06 +/- 0.02 vs 0.12 +/- 0.03 pmol/mg protein). At 1 year after surgery, rats with PHT showed hyperplasia of goblet cells in the small bowel (172.79 +/- 40.46 vs 121.76 +/- 20.74 /1,000 microm2) (p < 0.01), associated with an increase in ileal levels of TNFalpha (0.37 +/- 0.18 vs 0.17 +/- 0.08 pmol/mg protein) (p < 0.05), IL-1beta (0.28 +/- 0.14 vs 0.205 +/- 0.05 pmol/mg protein), and IL-10 (0.25 +/- 0.14 vs 0.20 +/- 0.11 pmol/mg protein).

CONCLUSIONS

The increase in TNFalpha and IL-1beta levels and the decrease in IL-10 level in the small bowel in rats with chronic prehepatic PHT suggest the existence of an inflammatory process related to goblet cell hyperplasia. This inflammation could be responsible for the intestinal epithelial remodeling that occurs in the long term in this experimental model.

Effects of the antimicrobial peptide BMAP-27 in a mouse model of obstructive jaundice stimulated by lipopolysaccharide

An experimental study was designed to investigate the efficacy of BMAP-27, a compound of the cathelicidin family, in neutralizing Escherichia coli 0111:B4 lipopolysaccharide (LPS) in bile duct-ligated mice. Main outcome measures were: endotoxin and TNF-alpha concentrations in plasma, evidence of bacterial translocation in blood and peritoneum, and lethality. Adult male BALB/c mice were injected intraperitoneally with 2 mg/kg E. coli 0111:B4 LPS 1 week after sham operation or bile duct ligation (BDL). Six groups were studied: sham with placebo, sham with 120 mg/kg tazobactam-piperacillin (TZP), sham with 1 mg/kg BMAP-27, BDL with placebo, BDL with 120 mg/kg TZP, and BDL with 1mg/kg BMAP-27. After LPS, TNF-alpha plasma levels were significantly higher in BDL mice compared to sham-operated animals. BMAP-27 achieved a significant reduction of plasma endotoxin and TNF-alpha concentration when compared with placebo- and TZP-treated groups. On the other hand, both TZP and BMAP-27 significantly reduced the bacterial growth compared with saline treatment. Finally, LPS induced 60% and 55% lethality in BDL placebo- and TZP-treated treated mice and no lethality in sham-operated mice, while only BMAP-27 significantly reduced the lethality to 10%. In light of its dual antimicrobial and anti-endotoxin properties, BMAP-27 could be an interesting compound to inhibit bacterial translocation and endotoxin release in obstructive jaundice.

The effect of caffeic acid phenethyl ester on bacterial translocation and intestinal damage in cholestatic rats

We investigated the effect of caffeic acid phenethyl ester in rat ileum injury induced by chronic biliary obstruction. Swiss albino rats were divided into three groups: Group 1, sham (n = 7); Group 2, common bile duct ligation (n = 7); and Group 3, common bile duct ligation plus caffeic acid phenethyl ester (n = 7). In the caffeic acid phenethyl ester-treated rats, ileum tissue levels of malondialdehyde and myeloperoxidase were significantly lower than those of the bile duct-ligated rats (P < 0.001). The levels of tumor necrosis factor-alpha, interleukin-6, and interleukin-1alpha in the caffeic acid phenethyl ester group were significantly lower than those in the bile duct ligation group (P < 0.03, P < 0.01, and P < 0.02 respectively). The present study demonstrates that intraperitoneal administration of caffeic acid phenethyl ester in bile duct-ligated rats reduces intestinal oxidative stress. This effect may be useful in the preservation of intestinal damage in cholestasis.

Amphibian peptides prevent endotoxemia and bacterial translocation in bile duct–ligated rats*

OBJECTIVE

To investigate the efficacy of amphibian antimicrobial peptides in preventing bacterial translocation and neutralizing endotoxins in bile duct-ligated rats.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

Research laboratory in a university hospital.

SUBJECTS

Adult male Wistar rats.

INTERVENTIONS

Adult male Wistar rats underwent sham operation or bile duct ligation (BDL). Eight groups were studied: sham operation with saline treatment, sham operation with 120 mg/kg tazobactam-piperacillin, sham operation with 2 mg/kg uperin 3.6, sham operation with 2 mg/kg magainin2, BDL with saline treatment, BDL with 120 mg/kg tazobactam-piperacillin, BDL with 2 mg/kg uperin 3.6, and BDL with 2 mg/kg magainin2.

MEASUREMENTS AND MAIN RESULTS

Main outcome measures were: endotoxin and tumor necrosis factor-alpha concentrations in plasma and evidence of bacterial translocation in blood, peritoneum, liver, and mesenteric lymph nodes. Endotoxin and tumor necrosis factor-alpha plasma levels were significantly higher in BDL rats compared with sham-operated animals. All amphibian peptides achieved a significant reduction of plasma endotoxin and tumor necrosis factor-alpha concentration when compared with saline- and tazobactam-piperacillin-treated groups. On the other hand, both tazobactam-piperacillin and peptides significantly reduced bacterial growth compared with the control. Tazobactam-piperacillin and magainin2 exerted the maximal inhibition of bacterial growth.

CONCLUSION

In conclusion, because of their multifunctional properties, amphibian peptides could be interesting compounds to inhibit bacterial translocation and endotoxin release in obstructive jaundice.

The role of nuclear factor-kappa B in bacterial translocation in cholestatic rats

Xanthinoxidase (XO) derived radical species are involved in bacterial translocation (BT) in cholestatic rats. The mechanism by which XO influences remains unclear. It has been shown recently that nuclear factor-kappa B (NF-kappaB), a ubiquitous transcription factor, can be activated by oxidative stress and thereby promote the process of BT. We investigated the effects of NF-kappaB inactivation on the incidence of BT in cholestatic rats. Sprague-Dawley rats were randomly assigned to one of eight groups: groups 1-4 were sham laparotomized rats either untreated (S1) or treated for 5 days with thalidomide (S2), curcumin (S3), or Inchin-ko (ICK; S4); groups 5-8 underwent common bile duct ligation (CBDL) for 5 days and were either untreated (C1) or treated with thalidomide (C2), curcumin (C3), or ICK (C4). After 5 days bacteriological cultures were performed from portal blood and V. cava, from the central mesenteric lymph node complex (MLN), spleen, and liver. The intensity of the activated NF-kappaB-subunit p65/p50 in the ileum mucosa was estimated by light microscopy and a scoring system from 1 to 20. Malondialdehyde (MDA) and myeloperoxidase activity (MPO) in the ileum were evaluated and expressed as U/g dry weight. Thalidomide and ICK reduced in CBDL-rats significantly the BT rate (63% vs. 18%, 63% vs. 30%, P<0.01). Enzyme estimations (MDA, MPO, and GSH) in sham operated animals showed no significant changes in the untreated groups compared with the treated groups. CBDL-rats pre-treatment with all three compounds caused a significant increase of MDA levels if groups were compared with the untreated C1-group (C1 31.6+/-7.7, C2 54.5+/-12.2, C3 53.3+/-11.2, and C4 47.2+/-9.4). GSH was reduced after the pre-treatment by all compounds but only significantly after curcumin pre-treatment (C1 vs. C3: 13.9+/-1.8 vs. 7.1+/-1.8; P<0.05). MPO estimations were significantly higher in the untreated C1-group if compared with groups C2, C3, and C4 (C1 1036.4+/-340.9, C2 709.9+/-125.9, C3 545.2+/-136.6, and C4 556.7+/-247.4; P<0.05). Thalidomide inhibited significantly the activation of NF-kappaB (C2 vs. C1: 6.0+/-4.5 vs. 12.7+/-5.3; P<0.01). Likewise, Curcumin and ICK suppressed NF-kappaB activation, but this did not reach significance in this experiment. NF-kappaB is involved in the process of BT in cholestatic rats and may be activated by XO derived ROS. We assume that the activated NF-kappaB initiates transcription of target genes inducing cytokine production, which in turn disrupts the tight junctions leading to BT from the intestinal lumen to the MLNs and circulation.

Prehepatic portal hypertension produces increased mast cell density in the small bowel and in mesenteric lymph nodes in the rat

BACKGROUND

Because most of the characteristics of the portal hypertensive enteropathy can be explained on the basis of increased levels of mast cell mediators, the purpose of the present paper was to study mast cell splanchnic infiltration.

METHODS

Duodenum, jejunum, ileum and mesenteric lymph node complex infiltration by mast cells was assayed by a stereological technique in control rats (group I; n = 5) and in an experimental model of portal hypertension (the portal vein-stenosed rat, group II; n = 5) at 6 weeks after operation.

RESULTS

Intestinal and mesenteric lymph node complex infiltration by mast cells increased in the animals with partial portal vein ligation. The mast cell density progressively increased distally along the small bowel. The mast cell increase in the mesenteric lymph node complex in portal vein-stenosed rats was greater than in the duodenum (P = 0.001), jejunum (P = 0.006) and ileum.

CONCLUSION

The rise of mast cells density in the small bowel and mesenteric lymph node complex in rats with partial portal vein ligation suggests that these cells are involved in the etiopathogenesis of experimental portal prehepatic hypertensive enteropathy.

Bacterial translocation and its consequences in patients with cirrhosis

Bacterial translocation is the passage of viable bacteria from the intestinal lumen to mesenteric lymph nodes and other extraintestinal sites. Spontaneous bacterial peritonitis is the main clinical consequence of bacterial translocation in cirrhosis. Translocation of bacterial products of viable or non-viable bacteria, such as endotoxin and/or bacterial DNA, through the intestinal wall could stimulate the immune system and the hyperdynamic circulatory state in cirrhosis with clinical consequences that are under evaluation. Bacterial translocation is currently considered the passage of viable gut flora across the intestinal barrier to extraluminal sites. Aerobic Gram-negative bacilli are the most common translocating bacteria. Intestinal bacterial overgrowth, impairment in permeability of the intestinal mucosal barrier, and deficiencies in local host immune defences are the major mechanisms postulated to favour bacterial translocation in cirrhosis. Bacterial translocation is a key step in the pathogenesis of spontaneous bacteraemia and spontaneous bacterial peritonitis in cirrhosis. Translocation of intestinal bacterial products from viable or non-viable bacteria, such as endotoxin and bacterial DNA, has recently been associated with pathophysiological events, such as activation of the immune system and derangement of the hyperdynamic circulatory status in cirrhosis. Clinical consequences of these effects of bacterial products are presently under investigation.

Nitric oxide and the hyperdynamic circulation in cirrhosis: is there a role for selective intestinal decontamination?

Abnormal vascular tone is responsible for many of the complications seen in cirrhosis making the identification of the pathophysiology of abnormal dilatation a major focus in hepatology research. The study of abnormal vascular tone is complicated by the multiple vascular beds involved (hepatic, splanchnic, peripheral, renal and pulmonary), the differences in the underlying cause of portal hypertension (hepatic versus pre-hepatic) and the slow evolution of the hyperdynamic state. The autonomic nervous system, circulating vasodilators and abnormalities in vascular smooth muscle cells (receptors, ion channels, signalling systems and contraction) have all been implicated. There is overwhelming evidence for an overproduction of NO (nitric oxide) contributing to the peripheral dilatation in both animal models of, and in humans with, cirrhosis and portal hypertension. This review focuses on the proposal that endotoxaemia, possibly from gut-derived bacterial translocation, causes induction of NOS (NO synthase) leading to increased vascular NO production, which is the primary stimulus for the development of vasodilatation in cirrhosis and its accompanying clinical manifestations. The current controversy lies not in whether NO production is elevated, but in which isoform of NOS is responsible. We review the evidence for endotoxaemia in cirrhosis and the factors contributing to gut-derived bacterial translocation, including intestinal motility and permeability, and finally discuss the possible role of selective intestinal decontamination in the management of circulatory abnormalities in cirrhosis.

Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of hepatobiliary disorders

Many nutraceuticals, conditionally essential nutrients, and botanical extracts have been proposed as useful in the management of liver disease. The most studied of these are addressed in terms of proposed mechanisms of action, benefits, hazards, and safe dosing recommendations allowed by current information. While this is an area of soft science, it is important to keep an open and tolerant mind, considering that many major treatment discoveries were in fact serendipitous accidents.

Renal metabolism of amino acids: its role in interorgan amino acid exchange

The kidneys play a role in the synthesis and interorgan exchange of several amino acids. The quantitative importance of renal amino acid metabolism in the body is not, however, clear. We review here the role of the kidney in the interorgan exchange of amino acids, with emphasis on quantitative aspects. We reviewed relevant literature by using a computerized literature search (PubMed) and checking relevant references from the identified articles. Our own data are discussed in the context of the literature. The kidney takes up glutamine and metabolizes it to ammonia. This process is sensitive to pH and serves to maintain acid-base homeostasis and to excrete nitrogen. In this way, the metabolism of renal glutamine and ammonia is complementary to hepatic urea synthesis. Citrulline, derived from intestinal glutamine breakdown, is converted to arginine by the kidney. Renal phenylalanine uptake is followed by stoichiometric tyrosine release, and glycine uptake is accompanied by serine release. Certain administered oligopeptides (eg, glutamine dipeptides) are converted by the kidneys to their constituent components before they can be used in metabolic processes. The kidneys play an important role in the interorgan exchange of amino acids. Quantitatively, for several important amino acids, the kidneys are as important as the gut in intermediary metabolism. The kidneys may be crucial "mediators" of the beneficial effects of specialized, disease-specific feeding solutions such as those enriched in glutamine dipeptides.

Administration of protegrin peptide IB-367 to prevent endotoxin induced mortality in bile duct ligated rats

BACKGROUND

Postoperative morbidity in patients with obstructive jaundice remains high because of increased susceptibility to endotoxin and the inflammatory cascade.

AIMS

An experimental study was designed to investigate the efficacy of protegrin peptide IB-367, an antimicrobial positively charged peptide, in neutralising Escherichia coli 0111:B4 lipopolysaccharide (LPS) in bile duct ligated rats.

METHODS

Adult male Wistar rats were injected intraperitoneally with 2 mg/kg E coli 0111:B4 LPS one week after sham operation or bile duct ligation (BDL). Six groups were studied: sham with placebo, sham with 120 mg/kg tazobactam-piperacillin (TZP), sham with 1 mg/kg IB-367, BDL with placebo, BDL with 120 mg/kg TZP, and BDL with 1 mg/kg IB-367.

RESULTS

Main outcome measures were: endotoxin and tumour necrosis factor alpha (TNF-alpha) concentrations in plasma, evidence of bacterial translocation in blood and peritoneum, and lethality. After LPS, TNF-alpha plasma levels were significantly higher in BDL rats compared with sham operated animals. IB-367 caused a significant reduction in plasma endotoxin and TNF-alpha concentrations compared with placebo and TZP treated groups. In contrast, both TZP and IB-367 significantly reduced bacterial growth compared with saline treatment. Finally, LPS induced 60% and 55% lethality in BDL placebo and TZP treated rats and no lethality in sham operated rats, while only IB-367 significantly reduced lethality to 10%.

CONCLUSIONS

By virtue of its dual antimicrobial and antiendotoxin properties, IB-367 could be an interesting compound to inhibit bacterial translocation and endotoxin release in obstructive jaundice.

Intestinal mucosal oxidative damage and bacterial translocation in cirrhotic rats

BACKGROUND

Bacterial translocation plays an important role in the pathogenesis of spontaneous bacterial peritonitis mainly due to intestinal bacterial overgrowth. Alterations in the functional integrity of the intestinal barrier caused by an increased production of free radical metabolites as a consequence of portal hypertension could also facilitate bacterial translocation in cirrhotic rats.

OBJECTIVE

The aim of the study was to determine intestinal mucosal lipid peroxidation and neutrophil infiltration and their relationship with portal hypertension and bacterial translocation in cirrhotic rats.

DESIGN

Eighteen male Sprague-Dawley rats with cirrhosis induced by carbon tetrachloride, administered by gavage, and eight control rats were included in the study.

METHODS

Samples of jejunum, ileum and caecum were obtained by laparotomy for the determination of malondialdehyde and myeloperoxidase as indexes of lipid peroxidation and neutrophil infiltration, respectively. Samples of ascitic and pleural fluids, mesenteric lymph nodes and ileal stools were obtained for the culture of microoganisms.

RESULTS

The concentration of malondialdehyde was significantly higher in ileal and caecal, but not in jejunal mucosa, in cirrhotic rats, mainly in those with ascites (P< 0.01), as compared to control rats (P< 0.01), and in cirrhotic rats with bacterial translocation compared to those without bacterial translocation (P< 0.01). No differences between groups were observed in the concentrations of myeloperoxidase in jejunum, ileum or caecum. A direct correlation between ileal malondialdehyde and portal pressure was observed (P< 0.01).

CONCLUSIONS

Cirrhotic rats, particularly those with ascites and bacterial translocation, show increased malondialdehyde levels in ileal and caecal mucosa. These results suggest that mucosal oxidative damage in ileum and caecum could favour bacterial translocation in cirrhotic rats.

Effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora and bacterial translocation in rats with experimental cirrhosis

BACKGROUND/AIMS

Probiotics and antioxidants could be alternatives to antibiotics in the prevention of bacterial infections in cirrhosis. The aim of the present study was to determine the effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora, endotoxemia, and bacterial translocation in cirrhotic rats.

METHODS

Twenty-nine Sprague-Dawley rats with cirrhosis induced by CCl(4) and ascites received Lactobacillus johnsonii La1 10(9)cfu/day in vehicle (antioxidants: vitamin C+glutamate) (n=10), vehicle alone (n=11), or water (n=8) by gavage. Another eight non-cirrhotic rats formed the control group. After 10 days of treatment, a laparotomy was performed to determine microbiological study of ileal and cecal feces, bacterial translocation, endotoxemia, and intestinal malondialdehyde (MDA) levels as index of intestinal oxidative damage.

RESULTS

Intestinal enterobacteria and enterococci, bacterial translocation (0/11 and 0/10 vs. 5/8, P<0.01), and ileal MDA levels (P<0.01) were lower in cirrhotic rats treated with antioxidants alone or in combination with Lactobacillus johnsonii La1 compared to cirrhotic rats receiving water. Only rats treated with antioxidants and Lactobacillus johnsonii La1 showed a decrease in endotoxemia with respect to cirrhotic rats receiving water (P<0.05).

CONCLUSIONS

Antioxidants alone or in combination with Lactobacillus johnsonii La1 can be useful in preventing bacterial translocation in cirrhosis.

Why do bacteria reach ascitic fluid?

Spontaneous bacterial peritonitis (SBP) is the most common and serious infection that develops in cirrhotic patients. Translocation of bacteria from their intestinal origin, alterations in immune defence mechanisms and deficiencies in the ascitic fluid antimicrobial activity seem to represent the main steps in the pathogenesis of SBP in cirrhosis. Among the factors determining the development of bacterial translocation, intestinal bacterial overgrowth (mainly related to decreased intestinal motility) and changes in the intestinal barrier appear to play an outstanding role. In conclusion, greater understanding of the pathogenesis of SBP will allow better identification of patients at high risk of developing this complication and contribute to the search for new strategies for its prevention.

Effect of 5-lipoxygenase inhibition on Kupffer cell clearance capacity in obstructive jaundiced rats

BACKGROUND

Obstructive jaundice is a common surgical problem. It may cause hepatic and Kupffer cell dysfunction. Previous studies demonstrated that 5-lipoxygenase inhibition prevents hepatic injury. However, its effect on Kupffer cell clearance capacity has not been determined yet.

MATERIALS AND METHODS

Rats were divided into four groups. In group 1 (sham control group), only bile duct dissection was performed. In other groups bile ducts were ligated and divided. In groups 1 and 2 saline, in group 3 ethanol, and in group 4 a 5-lipoxygenase inhibitor AA-861 was given intraperitoneally to the animals. Rats were sacrificed 14 days after the operations. Serum alkaline phosphatase, total bilirubin, and alanine aminotransferase levels were determined. Kupffer cell clearance capacity was measured using an in situ isolated hepatic perfusion technique. Hematoxylin-eosin-stained liver samples were evaluated under light microscope for histopathologic scoring.

RESULTS

Rats in the sham control group had significantly lower serum ALP and bilirubin values than those in the experimental groups with biliary obstruction. AA-861 administration significantly decreased serum ALT levels and histopathologic scores. There was no significant difference in ALT levels and histopathologic scores between the sham control and AA-861 groups. Kupffer cell clearance capacity was found to be significantly increased in the AA-861 group compared to other experimental groups with obstructive jaundice.

CONCLUSIONS

This study shows that leukotriene synthesis inhibition using AA-861 prevents hepatic damage and improves Kupffer cell clearance capacity in obstructive jaundiced rats. This may have significant implications for the management of patients with obstructive jaundice.

Ileal pouches: adaptation and inflammation

Ileal pouch-anal anastomosis (IPAA) has become the operation of choice following proctocolectomy for ulcerative colitis (UC) and familial adenomatous polyposis. Functioning ileal pouch mucosa undergoes histological changes resembling the colon (colonic metaplasia). The possible role of stasis and luminal factors--bile acids, short-chain fatty acids and bacteria--are discussed. It seems likely that colonic metaplasia is an adaptive response to the new luminal environment in IPAA. Inflammation in the ileal reservoir ('pouchitis') is the most significant late complication in IPAA. It occurs in 20-30% of patients and is virtually confined to those with prior UC. The clinical picture in pouchitis is highly variable; however, it can be easily categorized into three groups. Nevertheless, in most cases it is likely to represent recurrent UC in the ileal pouch. Current treatments and possible preventative strategies for pouchitis have been outlined.