Effect of glutamine and bile acid on hepatocyte apoptosis after bile duct ligation in the rat

Effects of Probiotic Use on Bacterial Translocation in Created Rat Models with Biliary Obstructions

Objective

The aim of this study was to investigate the protective effects of the combined use of probiotic strains on the development of bacterial translocation in addition to liver and intestinal tissue damage due to biliary obstruction in rats.

Materials and Methods

Here, 3 groups each consisting of 10 rats were created:group 1 (sham group), group 2 (obstructive jaundice), and group 3 (obstructive jaundice+probiotic). Groups 1 and 2 were given 1 cc physiological saline solution by oral gavage twice a day; group 3 was given a probiotic solution that included Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium bifidum, Enterococcus faecium, and Bifidobacterium longum microorganisms by oral gavage twice a day.

Results

Markers for liver damage were also found to be significantly improved (p<0.05) in the treatment group (group 3). When compared with groups 2 and 3 in terms of liver histology, damage was found to be significantly more severe in group 2 (p<0.01). With regard to ileal villous depth and ileal inflammation, the pathology was found to be significantly more severe in group 2 than that in group 3 (p<0.05). In blood, spleen, and mesenteric lymph node cultures, group 2 showed a microbiological growth rate of 33.8-58.8%, whereas group 3 showed a microbiological growth rate of 14.3-28.6%. This reduction was evaluated to be statistically significant (p<0.05).

Conclusion

Our study showed that the combined use of a probiotic in bile duct obstructions reduced bacterial translocation and alleviated pathological changes arising in the liver and terminal ileum histology.

Risk Prediction for Early Biliary Infection after Percutaneous Transhepatic Biliary Stent Placement in Malignant Biliary Obstruction

PURPOSE

To establish a nomogram for predicting the occurrence of early biliary infection (EBI) after percutaneous transhepatic biliary stent (PTBS) placement in malignant biliary obstruction (MBO).

MATERIALS AND METHODS

In this multicenter study, patients treated with PTBS for MBO were allocated to a training cohort or a validation cohort. The independent risk factors for EBI selected by multivariate analyses in the training cohort were used to develop a predictive nomogram. An artificial neural network was applied to assess the importance of these factors in predicting EBI. The predictive accuracy of this nomogram was determined by concordance index (c-index) and a calibration plot, both internally and externally.

RESULTS

A total of 243 patients (training cohort: n = 182; validation cohort: n = 61) were included in this study. The independent risk factors were length of obstruction (odds ratio [OR], 1.061; 95% confidence interval [CI], 1.013-1.111; P = .012), diabetes (OR, 5.070; 95% CI, 1.917-13.412; P = .001), location of obstruction (OR, 2.283; 95% CI, 1.012-5.149; P = .047), and previous surgical or endoscopic intervention (OR, 3.968; 95% CI, 1.709-9.217; P = .001), which were selected into the nomogram. The c-index values showed good predictive performance in the training and validation cohorts (0.792 and 0.802, respectively). The optimum cutoff value of risk was 0.25.

CONCLUSIONS

The nomogram can facilitate the early and accurate prediction of EBI in patients with MBO who underwent PTBS. Patients with high risk (> 0.25) should be administered more effective prophylactic antibiotics and undergo closer monitoring.

The Effect of Calcium Dobesilate on Liver Damage in Experimental Obstructive Jaundice

Purpose/Aim of the study: Inflammation and oxidative stress are two significant factors affecting the degree of liver damage in obstructive jaundice. The aim of this study was to evaluate the effect of calcium dobesilate (CaDob), an effective antioxidant and anti-inflammatory drug, on damage to liver caused by experimental obstructive jaundice.

MATERIALS AND METHODS

30 rats in total were randomly placed into three groups, each group consisting of 10 rats. The sham group (Group 1) only received solely laparotomy. In the control group (Group 2), ligation was applied to the biliary tract and no treatment was implemented. In the CaDob group (Group 3), following ligation of the biliary tract, 100 mg/kg/day CaDob was implemented via an orogastric tube for a 10-day period. Liver tissue and blood samples were taken for histopathological and biochemical examination.

RESULTS

The CaDob group had significantly lower test values for serum liver functions when compared to the control group. Statistically lower levels of tissue malondialdehyde (MDA) and fluorescent oxidation products (FOP) were detected in the CaDob group, and the CaDob group had significantly higher levels of sulfydryl (SH) than the control group. Histopathological scores in the CaDob group were found out to be statistically less than the scores the control group received (p < 0.05).

CONCLUSIONS

CaDob treatment repaired the histpatological changes induced by bile duct ligation. The hepatoprotective effects of CaDob can be associated with its antioxidant properties of the drug.

The metabolites of glutamine prevent hydroxyl radical-induced apoptosis through inhibiting mitochondria and calcium ion involved pathways in fish erythrocytes

The present study explored the apoptosis pathways in hydroxyl radicals ((∙)OH)-induced carp erythrocytes. Carp erythrocytes were treated with the caspase inhibitors in physiological carp saline (PCS) or Ca(2+)-free PCS in the presence of 40μM FeSO4/20μM H2O2. The results showed that the generation of reactive oxygen species (ROS), the release of cytochrome c and DNA fragmentation were caspase-dependent, and Ca(2+) was involved in calpain activation and phosphatidylserine (PS) exposure in (∙)OH-induced carp erythrocytes. Moreover, the results suggested that caspases were involved in PS exposure, and Ca(2+) was involved in DNA fragmentation in (∙)OH-induced fish erythrocytes. These results demonstrated that there might be two apoptosis pathways in fish erythrocytes, one is the caspase and cytochrome c-dependent apoptosis that is similar to that in mammal nucleated cells, the other is the Ca(2+)-involved apoptosis that was similar to that in mammal non-nucleated erythrocytes. So, fish erythrocytes may be used as a model for studying oxidative stress and apoptosis in mammal cells. Furthermore, the present study investigated the effects of glutamine (Gln)'s metabolites [alanine (Ala), citrulline (Cit), proline (Pro) and their combination (Ala10Pro4Cit1)] on the pathways of apoptosis in fish erythrocytes. The results displayed that Ala, Cit, Pro and Ala10Pro4Cit1 effectively suppressed ROS generation, cytochrome c release, activation of caspase-3, caspase-8 and caspase-9 at the physiological concentrations, prevented Ca(2+) influx, calpain activation, PS exposure, DNA fragmentation and the degradation of the cytoskeleton and oxidation of membrane and hemoglobin (Hb) and increased activity of anti-hydroxyl radical (AHR) in (∙)OH-induced carp erythrocytes. Ala10Pro4Cit1 produced a synergistic effect of inhibited oxidative stress and apoptosis in fish erythrocytes. These results demonstrated that Ala, Cit, Pro and their combination can protect mammal erythrocytes and nucleated cells against oxidative stress and apoptosis. The studies supported the use of Gln, Ala, Cit and Pro as oxidative stress and apoptosis inhibitors in mammal cells and the hypothesis that the inhibited effects of Gln on oxidative stress and apoptosis are at least partly dependent on that of its metabolites in mammalian.

Preconditioning with glutamine protects against ischemia/reperfusion-induced hepatic injury in rats with obstructive jaundice

OBJECTIVE

To ascertain whether glutamine (Gln) pretreatment protects rats with obstructive jaundice from hepatic ischemia/reperfusion (I/R) injury and to determine the underlying molecular mechanisms.

METHODS

An obstructive jaundice rat model was developed by bile duct ligation. On the first day after the operation, all rats were randomized into two groups and received oral Gln or normal saline (NS) daily for 7 days. Then both groups underwent a 15-min liver ischemia via the Pringle maneuver. Blood samples as well as liver and intestinal tissues were harvested and measured after 1, 6 and 24 h of reperfusion.

RESULTS

The results showed that the histological morphology of the liver and intestinal tissues significantly improved in the Gln group after I/R injury compared with the NS group. Serum proteins and enzymes associated with hepatic function also significantly improved in the Gln group. The level of glutathione increased and the levels of malondialdehyde and myeloperoxidase decreased in the Gln group. The levels of interleukin-1β and tumor necrosis factor-α decreased in the Gln group. Moreover, bcl-2 protein expression was upregulated and intercellular adhesion molecule 1 and bax protein expression downregulated in the Gln group; the caspase 3 mRNA level significantly increased in the Gln group.

CONCLUSIONS

The study demonstrates that preconditioning with Gln significantly improves hepatic structure and function after I/R injury in rats with obstructive jaundice. The protective effect of Gln was mediated by the inhibition of reactive oxygen species and inflammation as well as a reduction in hepatocyte apoptosis.

Combined effects of tauroursodeoxycholic Acid and glutamine on bacterial translocation in obstructive jaundiced rats:

BACKGROUND

Bacterial Translocation is believed to be an important factor on mortality and morbidity in Obstructive Jaundiced.

AIMS

We investigated the probable or estimated positive effects of tauroursodeoxycholic acid, which has antibacterial and regulatory effects on intestinal flora, together with glutamine on BT in an experimental obstructive jaundiced rat model.

STUDY DESIGN

Animal experimentation.

METHODS

Forty adult, male, Sprague Dawley rats were used in this study. Animals were randomised and divided into five groups of eight each: sham (Sh); control (common bile duct ligation, CBDL); and supplementation groups administered tauroursodeoxycholic acid (CBDL+T), glutamine (CBDL+G), or tauroursodeoxycholic acid plus glutamine (CBDL+TG). Blood and liver, spleen, MLN, and ileal samples were taken via laparotomy under sterile conditions for investigation of bacterial translocation and intestinal mucosal integrity and hepatic function tests on the tenth postoperative day.

RESULTS

There were statistically significant differences in BT rates in all samples except the spleen of the CBDL+TG group compared with the CBDL group (p=0.041, p=0.026, and p=0.041, respectively).

CONCLUSION

It is essential to protect hepatic functions besides maintaining intestinal mucosal integrity in the active struggle against BT occurring in obstructive jaundice. The positive effect on intestinal mucosal integrity can be increased if glutamine is used with tauroursodeoxycholic acid, which also has hepatoprotective and immunomodulatory features.

Effects of glutamine and curcumin on bacterial translocation in jaundiced rats

AIM: To investigate the effect of curcumin on bacterial translocation and oxidative damage in an obstructive jaundice model and compare the results to glutamine, an agent known to be effective and clinically used.

METHODS: Twenty-four female Wistar-Albino rats, weighing 200-250 g, were randomly divided into three groups (8 in each group). After ligation of the common bile duct in all animals, Group I received oral normal saline, Group II received oral glutamine and Group III received oral curcumin for seven days. Blood samples via cardiac puncture, tissue samples (terminal ileum, liver and mesenteric lymph node) and peritoneal fluid were obtained from the animals at the time of death to investigate bacterial translocation and oxidative damage.

RESULTS: We observed that both glutamine and curcumin reduced bacterial translocation in blood, hepatocellular damage, plasma cytokine levels, oxidative tissue damage and apoptosis significantly compared to the control group. Additionally, glutamine showed protective effects on ileal epithelium and reduced villus atrophy.

CONCLUSION: On the basis of these findings, both curcumin and glutamine are thought to be effective in preventing or reducing bacterial translocation and oxidative damage in obstructive jaundice.

Influence of glutamine on morphological and functional changes of liver in the presence of extrahepatic biliary obstruction in rats

PURPOSE: To study the influence of glutamine on functional and morphological changes of liver in the extrahepatic biliary obstruction through an experimental model in rats. METHODS: Seventy Wistar rats were divided into four groups: control (group C) fictitious operation, (group FO), submitted to laparotomy with handling of bile ducts, but without hepatic duct ligation, (group EBO) submitted to laparotomy and hepatic duct ligation, one of them submitted to supplementation with glutamine 2% (group G). The control group consisted of 6 animals. The animals from groups FO, EBO and G were divided into three groups consisting of 6 animals each, being sacrificed at 7, 14 and 21 days after operation, respectively. Blood samples were collected for biochemical analysis and a fragment of liver tissue was collected from the middle lobe for histological analysis. RESULTS: Both for biochemical analysis (BT, aspartate and alanine aminotransferase AST, ALT and alkaline phosphatase FAL) and for histopathological changes (fibrosis, portal inflammation, parenchymal inflammation, hepatocytic changes and duct proliferation), no statistical difference between groups submitted to extrahepatic biliary obstruction (EBO) with and without treatment with glutamine (G) was observed. CONCLUSION: Glutamine supplementation did not alter the prognosis of liver enzymes and histopathological changes in animals submitted to extrahepatic biliary obstruction.

Protective effect of parenteral glutamine supplementation on hepatic function in very low birth weight infants

BACKGROUND & AIMS

Hepatic dysfunction is one of the most frequent complications of parenteral nutrition. Very low birth weight (VLBW) infants are more sensitive to liver injury due to physiological immaturity. Our studies in animals showed that glutamine supplementation could attenuate TPN-associated liver injury. The aim of study was to investigate whether parenteral glutamine supplementation can improve hepatic tolerance in VLBW infants.

METHODS

We performed a double-blind, randomized, and controlled clinical study to investigate whether parenteral glutamine supplementation can improve hepatic tolerance in VLBW infants. Thirty VLBW infants at two children's centers were randomly assigned to either a control group or a glutamine-supplemented group. The primary endpoints were hepatic function and mortality. The secondary endpoints were the time to achieve full enteral nutrition, episodes of gastric residuals, duration of parenteral nutrition, weight and head circumference gain, length of hospitalization, and days on ventilator.

RESULTS

The serum levels of aspartate aminotransferase (AST) and total bilirubin (Tbi) were decreased after PN in the glutamine-supplemented group (P < 0.05). No deaths occurred in this study. Four infants assigned to the control group and two infants in the glutamine-supplemented group were withdrawn from the study, according to intention to treat: relative risk [RR]: 1.182; 95% confidence interval [CI]: 0.937-1.490.

CONCLUSIONS

Parenteral glutamine supplementation can improve hepatic tolerance in very low birth weight infant, suggesting a hepato-protective effect.

Z-LLY-FMK attenuates intestinal apoptosis after bile duct ligation in rats

Apoptosis is an important process in a wide variety of different biological systems. In addition to caspases, recently, calpains, another family of proteases, have been found to be involved in apoptosis of many cell systems. This study is designed with the aims to evaluate the possible effect of Z-LLY-FMK (a calpain inhibitor) on intestine apoptosis after bile duct ligation in rats. Male Sprague-Dawley rats weighing 250-300 g were randomized to five groups (n = 6 in each group). Group 1 (CONTROL: C) underwent Sham operation and were simultaneously treated with the same amount of normal saline. Group 2 (CONTROL with DMSO: CDMSO) underwent Sham operation and were simultaneously treated with the same amount of dimethylsulfoxide (DMSO). Group 3 (Obstructive jaundice: OB) underwent common bile duct ligation without any other manipulation. Group 4 (Obstructive jaundice with Z-LLY-FMK: OBZLLY) underwent common bile duct ligation and were simultaneously treated with Z-LLY-FMK (dissolved in DMSO). Group 5 (Obstructive jaundice with ZFA-FMK: OBZFA) underwent common bile duct ligation and were simultaneously treated with ZFA-FMK (dissolved in DMSO). After 3 days, intestine tissue was harvested for apoptosis measurements. There was no significant difference between Sham operation group (C) and Sham operation with DMSO group (CDMSO) either in jejunum (P = 0.924) or in ileum (P = 0.996). When compared to Sham operation group (C), increased intestine apoptosis occurred in either jejunum (P < 0.001) or in ileum (P < 0.001) after common bile duct ligation (OB). After administration of Z-LLY-FMK (OBZLLY), the increased intestine apoptosis after common bile duct ligation (OB) was significantly diminished either in jejunum or in ileum (P < 0.001 and P < 0.001). Moreover, administration of ZFA (OBZFA) failed to show the same phenomenon in either jejunum (P = 0.993) or ileum (P = 0.485). There was a significant difference in intestine apoptosis in either jejunum (P < 0.001) or in ileum (P < 0.001) between OBZLLY group and OBZFA group. Significantly increased intestine apoptosis occurred after common bile duct ligation. The administration of Z-LLY-FMK could effectively diminish the intestine apoptosis after common bile duct ligation, whereas the administration of ZFA-FMK failed to show the same effect.

Effect of Boc-D-Fmk on hepatocyte apoptosis after bile duct ligation in rat and survival rate after endotoxin challenge

BACKGROUND AND AIM

Retention and accumulation of toxic hydrophobic bile salts within hepatocytes may cause hepatocyte toxicity by inducing apoptosis. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. Boc-D-FMK is a cell-permeable irreversible inhibitor of caspase and recent data suggest that it might block the processing of many caspases. The purpose of the present study was to evaluate the possible effect of Boc-D-FMK on hepatocyte apoptosis and on survival rate after bile duct ligation in the rat.

METHODS

Male Sprague-Dawley rats, weighing 280-300 g were randomized to three groups of eight rats each. Group 1 (OBBOC-D) underwent common bile duct ligation and simultaneous treatment with Boc-D-FMK-fmk (dissolved in dimethylsulfoxide [DMSO]). Group 2 (OBZFA) underwent common bile duct ligation and simultaneous treatment with ZFA-fmk (dissolved in DMSO). Group 3 (SHAM) underwent sham operation and simultaneous treatment with the same amount of dimethylsulfoxide (DMSO, n = 4) or the same amount of normal saline (n = 4). After 3 days, liver tissue was harvested for histopathological analysis and measurements of apoptosis. Survival rates were measured in a separate experiment in which animals underwent the same protocol. The animals received endotoxin (15 mg/kg) in the afternoon of the third postoperative day. Animals were observed for 48 h and the survival rates were recorded.

RESULTS

When compared with sham operation, common bile duct ligation with ZFA-fmk (placebo) significantly increased hepatocyte apoptosis (P < 0.001). When compared with the OBZFA group, Boc-D-FMK significantly diminished the increased hepatocyte apoptosis in the OBBOC-D group (P < 0.001). There is no difference in hepatocyte apoptosis (P = 0.05) between OBBOC-D and SHAM groups. After endotoxin challenge, the 48 h survival rates were 100%, 87.5% and 62.5% for the SHAM, OBBOC-D and OBZFA groups, respectively.

CONCLUSIONS

Boc-D-FMK-fmk effectively attenuated the hepatocyte apoptosis in bile duct-ligated rats and may improve the survival rates after endotoxin challenge.

Glutamine attenuates TPN-associated liver injury in infant rabbits

The aim of this study was to assess the effects of parenteral alanyl-glutamine dipeptide (Ala-Gln) on TPN-associated liver injury. Forty-three New Zealand rabbits (6-8 days old) were divided into three groups: 12 in the control group (maternal fed); 18 in the TPN group (TPN for 10 days); 13 in the Gln-PN group (TPN+Ala-Gln 400 mg kg(-1) day(-1) for 10 days). At the end of the experiment, liver function and histology were evaluated; MDA content of liver tissues and hepatocyte apoptosis by TUNEL assay were also determined. The serum concentration of direct bilirubin and bile acid in the Gln-PN group was significantly lower than TPN group (P < 0.05), but showed no difference compared with the control group. AST level of the Gln-PN group was lower than the other two groups. The light microscopy (LM) features in the TPN group included cholestasis or diffuse steatosis, while in the Gln-PN group, inflammatory infiltration and mild hydropic degenerative changes were mainly found without obvious cholestasis or proliferation of bile ducts. The electron microscopy appearances corresponded with LM findings. The liver MDA content in the Gln-PN group was clearly lower than the TPN group (P < 0.05), and was lower without statistical significance compared with control group. TUNEL assays showed the ratio of apoptotic hepatocytes in the TPN group was the highest among all the groups (44.59 +/- 6.68 vs. 0.92 +/- 0.85 in the control group, P < 0.01; 44.59 +/- 6.68 vs. 4.14 +/- 2.76 in the Gln-PN group, P < 0.01). There were significantly fewer apoptotic hepatocytes in the Gln-PN group. From this study, we found that glutamine dipeptide supplementation could attenuate TPN-associated liver injury in infant rabbits, and could also decrease liver MDA production and hepatocyte apoptosis during total parenteral nutrition.

Inflammatory response in patients with malignant obstructive jaundice

OBJECTIVE

Surgery in patients with malignant obstructive jaundice is associated with increased risks for postoperative septic complications. The aim of this study was to investigate the inflammatory and the local cellular immune response in patients accepted for surgery because of tumours in the hepatic-pancreatic-biliary (HPB) tract.

MATERIAL AND METHODS

Patients with obstructive jaundice (group HPB(+)) were compared with those without (HPB(-)). Patients undergoing surgery for benign abdominal disorders served as controls. Obstructive jaundice was present in 18 out of 33 HPB patients. Preoperatively, blood was analysed for bacteria, endotoxins and cytokines (TNF-alpha, IL-6 and IL-10). At operation, mesenteric lymph nodes (MLNs) were excised for bacterial cultures using standard microbiological techniques, and immunohistochemistry, using antibodies CD4 and CD8 (mainly staining T lymphocytes), CD68 (macrophages), and anti-caspase-3 (to determine the rate of apoptosis).

RESULTS

Bacterial translocation was not demonstrated in any of the patients. Increased preoperative concentrations of endotoxins were found in group HPB(+). The number of macrophages and the rate of apoptosis in MLNs were increased in jaundiced patients, while the number of T lymphocytes was decreased.

CONCLUSIONS

Malignant obstructive jaundice causes increased blood concentrations of endotoxins and cytokines, an increased number of macrophages in MLNs, a higher rate of apoptosis in MLNs, but a decreased number of T lymphocytes in MLNs. The lymphocyte depletion is probably due to the increased rate of apoptosis, and might reduce the ability of jaundiced patients to eradicate infection.

Effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in rat

AIM: Retention and accumulation of toxic hydrophobic bile salts within hepatocyte may cause hepatocyte toxicity by inducing apoptosis. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. Z-Val-Ala-Asp (OMe)-fluoromethyl ketone (ZVAD-fmk) is a cell-permeable irreversible inhibitor of caspase. The purpose of this study was to evaluate the possible effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in the rat.

METHODS: Male Sprague-Dawley rats, weighing 250-300 g, were randomized to five groups of five rats each. Group 1 underwent common bile duct ligation and simultaneous treatment with ZVAD-fmk (dissolved in dimethylsulfoxide (DMSO)). Group 2 underwent common bile duct ligation and simultaneous treatment with Z-Phe-Ala-fluoromethyl ketone ( ZFA-fmk, dissolved in DMSO). Group 3 underwent sham operation and simultaneous treatment with the same amount of DMSO. Group 4 underwent sham operation and simultaneous treatment with the same amount of normal saline. Group 5 underwent common bile duct ligation without other manipulation. After three days, liver tissue was harv-ested for histopathologic analysis and measurements of apoptosis.

RESULTS: When compared with sham operation, common bile duct ligation significantly increased hepatocyte apoptosis (P = 0.008) and ductular proliferation (P = 0.007). ZVAD-fmk significantly diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation (P = 0.008 and P = 0.007, respectively). ZFA did not show the same effects.

CONCLUSION: Hepatocyte apoptosis and ductular proliferation significantly increased after common bile duct ligation. ZVAD-fmk effectively diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation, whereas ZFA-fmk did not.