The Gastrointestinal Exertional Heat Stroke Paradigm: Pathophysiology, Assessment, Severity, Aetiology and Nutritional Countermeasures.

Exertional heat stroke (EHS) is a life-threatening medical condition involving thermoregulatory failure and is the most severe condition along a continuum of heat-related illnesses. Current EHS policy guidance principally advocates a thermoregulatory management approach, despite growing recognition that gastrointestinal (GI) microbial translocation contributes to disease pathophysiology. Contemporary research has focused to understand the relevance of GI barrier integrity and strategies to maintain it during periods of exertional-heat stress. GI barrier integrity can be assessed non-invasively using a variety of in vivo techniques, including active inert mixed-weight molecular probe recovery tests and passive biomarkers indicative of GI structural integrity loss or microbial translocation. Strenuous exercise is strongly characterised to disrupt GI barrier integrity, and aspects of this response correlate with the corresponding magnitude of thermal strain. The aetiology of GI barrier integrity loss following exertional-heat stress is poorly understood, though may directly relate to localised hyperthermia, splanchnic hypoperfusion-mediated ischemic injury, and neuroendocrine-immune alterations. Nutritional countermeasures to maintain GI barrier integrity following exertional-heat stress provide a promising approach to mitigate EHS. The focus of this review is to evaluate: (1) the GI paradigm of exertional heat stroke; (2) techniques to assess GI barrier integrity; (3) typical GI barrier integrity responses to exertional-heat stress; (4) the aetiology of GI barrier integrity loss following exertional-heat stress; and (5) nutritional countermeasures to maintain GI barrier integrity in response to exertional-heat stress.

Postoperative symbiotic in patients with head and neck cancer: a double-blind randomised trial.

Studies on the 'gut origin of sepsis' have suggested that stressful insults, such as surgery, can affect intestinal permeability, leading to bacterial translocation. Symbiotics have been reported to be able to improve gut permeability and modulate the immunologic system, thereby decreasing postoperative complications. Therefore we aimed to evaluate the postoperative use of symbiotics in head and neck cancer surgical patients for intestinal function and permeability, as well as the postoperative outcomes. Patients were double-blind randomised into the symbiotic (n 18) or the control group (n 18). Samples were administered twice a day by nasoenteric tube, starting on the 1st postoperative day until the 5th to 7th day, and comprised 109 colony-forming units/ml each of Lactobacillus paracasei, L. rhamnosus, L. acidophilus, and Bifidobacterium lactis plus 6 g of fructo-oligosaccharides, or a placebo (6 g of maltodextrin). Intestinal function (day of first evacuation, total stool episodes, stool consistency, gastrointestinal tract symptoms and gut permeability by diamine oxidase (DAO) enzyme) and postoperative complications (infectious and non-infectious) were assessed. Results of comparison of the pre- and postoperative periods showed that the groups were similar for all outcome variables. In all, twelve patients had complications in the symbiotic group v. nine in the control group (P>0·05), and the preoperative-postoperative DAO activity ranged from 28·5 (sd 15·4) to 32·7 (sd 11·0) ng/ml in the symbiotic group and 35·2 (sd 17·7) to 34·1 (sd 12·0) ng/ml in the control group (P>0·05). In conclusion, postoperative symbiotics did not impact on intestinal function and postoperative outcomes of head and neck surgical patients.

Randomised clinical trial: the effects of a multispecies probiotic vs. placebo on innate immune function, bacterial translocation and gut permeability in patients with cirrhosis.

BACKGROUND: Probiotics may correct intestinal dysbiosis and proinflammatory conditions in patients with liver cirrhosis. AIM: To test the effects of a multispecies probiotic on innate immune function, bacterial translocation and gut permeability. METHODS: In a randomised, double blind, placebo-controlled study, stable cirrhotic out-patients either received a daily dose of a probiotic powder containing eight different bacterial strains (Ecologic Barrier, Winclove, Amsterdam, The Netherlands) (n = 44) or a placebo (n = 36) for 6 months and were followed up for another 6 months. RESULTS: We found a significant but subclinical increase in neutrophil resting burst (2.6-3.2%, P = 0.0134) and neopterin levels (7.7-8.4 nmol/L, P = 0.001) with probiotics but not with placebo. Probiotic supplementation did not have a significant influence on neutrophil phagocytosis, endotoxin load, gut permeability or inflammatory markers. Ten severe infections occurred in total; one during intervention in the placebo group, and five and four after the intervention has ended in the probiotic and placebo group, respectively. Liver function showed some improvement with probiotics but not with placebo. CONCLUSIONS: Probiotic supplementation significantly increased serum neopterin levels and the production of reactive oxygen species by neutrophils. These findings might explain the beneficial effects of probiotics on immune function. Furthermore, probiotic supplementation may be a well-tolerated method to maintain or even improve liver function in stable cirrhosis. However, its influence on gut barrier function and bacterial translocation in cirrhotic patients is minimal.

Investigation of the effects of oleuropein rich diet on rat enteric bacterial flora.

OBJECTIVES AND BACKGROUND: Oleuropein is a phenolic compound of olive leaves. Enteric bacterial flora is very important for human health and diet is a directly affecting factor of enteric bacterial flora composition. In this study, it was hypothesized that oleuropein could reduce total aerobic bacterial count in rat caecal flora. METHODS: Twenty adult, male, Wistar albino rats were randomly divided into two groups. Group C (n=10) was fed with standard rat chow and water for 30 days. Group O (n=10) received olive leaf extract 20 mg/kg/day by intragastric gavage in addition to standard rat chow and water for 30 days. One gram of caecal content was collected from each rat and then consecutive 10-fold serial dilutions were prepared with a final concentration of 10-8. Then 0.1 ml of each dilution were spread onto the surfaces of Plate Count Agar and Violet Red Bile Glucose Agar to enumerate the aerobic enteric bacteria. RESULTS: Total aerobic bacterial counts of Group O were significantly lower than of Group C in all agar plates inoculated with ceacal samples for every dilution (p<0.05). CONCLUSION: Adding oleuropein to enteral feeding solutions of critically ill patients may be adventageous in the presence of clinical conditions predisposing to bacterial translocation by reducing enteric bacterial counts (Tab. 1, Ref. 32).

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.

Genetic susceptibility to increased bacterial translocation influences the response to biological therapy in patients with Crohn's disease.

OBJECTIVE: The aetiology of Crohn's disease (CD) has been related to nucleotide-binding oligomerisation domain containing 2 (NOD2) and ATG16L1 gene variants. The observation of bacterial DNA translocation in patients with CD led us to hypothesise that this process may be facilitated in patients with NOD2/ATG16L1-variant genotypes, affecting the efficacy of anti-tumour necrosis factor (TNF) therapies. DESIGN: 179 patients with Crohn's disease were included. CD-related NOD2 and ATG16L1 variants were genotyped. Phagocytic and bactericidal activities were evaluated in blood neutrophils. Bacterial DNA, TNFα, IFNγ, IL-12p40, free serum infliximab/adalimumab levels and antidrug antibodies were measured. RESULTS: Bacterial DNA was found in 44% of patients with active disease versus 23% of patients with remitting disease (p=0.01). A NOD2-variant or ATG16L1-variant genotype was associated with bacterial DNA presence (OR 4.8; 95% CI 1.1 to 13.2; p=0.001; and OR 2.4; 95% CI 1.4 to 4.7; p=0.01, respectively). This OR was 12.6 (95% CI 4.2 to 37.8; p=0.001) for patients with a double-variant genotype. Bacterial DNA was associated with disease activity (OR 2.6; 95% CI 1.3 to 5.4; p=0.005). Single and double-gene variants were not associated with disease activity (p=0.19). Patients with a NOD2-variant genotype showed decreased phagocytic and bactericidal activities in blood neutrophils, increased TNFα levels in response to bacterial DNA and decreased trough levels of free anti-TNFα. The proportion of patients on an intensified biological therapy was significantly higher in the NOD2-variant groups. CONCLUSIONS: Our results characterise a subgroup of patients with CD who may require a more aggressive therapy to reduce the extent of inflammation and the risk of relapse.

Enteric glia protect against Shigella flexneri invasion in intestinal epithelial cells: a role for S-nitrosoglutathione.

BACKGROUND: Enteric glial cells (EGCs) are important regulators of intestinal epithelial barrier (IEB) functions. EGC-derived S-nitrosoglutathione (GSNO) has been shown to regulate IEB permeability. Whether EGCs and GSNO protect the IEB during infectious insult by pathogens such as Shigella flexneri is not known. METHODS: S flexneri effects were characterised using in vitro coculture models of Caco-2 cells and EGCs (or GSNO), ex vivo human colonic mucosa, and in vivo ligated rabbit intestinal loops. The effect of EGCs on S flexneri-induced changes in the invasion area and the inflammatory response were analysed by combining immunohistochemical, ELISA and PCR methods. Expression of small G-proteins was analysed by western blot. Expression of ZO-1 and localisation of bacteria were analysed by fluorescence microscopy. RESULTS: EGCs significantly reduced barrier lesions and inflammatory response induced by S flexneri in Caco-2 monolayers. The EGC-mediated effects were reproduced by GSNO, but not by reduced glutathione, and pharmacological inhibition of pathways involved in GSNO synthesis reduced EGC protecting effects. Furthermore, expression of Cdc42 and phospho-PAK in Caco-2 monolayers was significantly reduced in the presence of EGCs or GSNO. In addition, changes in ZO-1 expression and distribution induced by S flexneri were prevented by EGCs and GSNO. Finally, GSNO reduced S flexneri-induced lesions of the IEB in human mucosal colonic explants and in a rabbit model of shigellosis. CONCLUSION: These results highlight a major protective function of EGCs and GSNO in the IEB against S flexneri attack. Consequently, this study lays the scientific basis for using GSNO to reduce barrier susceptibility to infectious or inflammatory challenge.

Probiotic dahi containing Lactobacillus casei protects against Salmonella enteritidis infection and modulates immune response in mice.

In the present study, effect of dahi containing probiotic Lactobacillus casei (probiotic dahi) was evaluated to modulate immune response against Salmonella enteritidis infection in mice. Animals were fed with milk products along with standard diet for 2 and 7 days prior to the S. enteritidis challenge and continued on the respective dairy food-supplemented diets during the postchallenge period. Translocation of S. enteritidis in spleen and liver, beta-galactosidase and beta-glucuronidase enzymatic activities and secretory IgA (sIgA) in intestinal fluid, lymphocyte proliferation, and cytokine (interleukin [IL]-2, IL-4, IL-6, and interferon-gamma [IFN-gamma]) production in cultured splenocytes were assessed on day 2, 5, and 8 of the postchallenge period. Colonization of S. enteritidis in liver and spleen was remarkably low in probiotic dahi-fed mice than mice fed milk and control dahi. The beta-galactosidase and beta-glucuronidase activities in intestinal fluid collected from mice prefed for 7 days with probiotic dahi were significantly lower at day 5 and 8 postchallenge than in mice fed milk and control dahi. Levels of sIgA and lymphocyte proliferation rate were also significantly increased in probiotic dahi-fed mice compared with the other groups. Production of IL-2, IL-6, and IFN-gamma increased, whereas IL-4 decreased in splenic lymphocytes collected from probiotic dahi-fed mice. Data showed that dahi prefed for 7 days before S. enteritidis challenge was more effective than when mice were prefed for 2 days with dahi. Moreover, probiotic dahi was more efficacious in protecting against S. enteritidis infection by enhancing innate and adaptive immunity than fermented milk and normal dahi. Results of the present study suggest that prefeeding of probiotic dahi may strengthen the consumer's immune system and may protect infectious agents like S. enteritidis.

Intestinal barrier function in response to abundant or depleted mucosal glutathione in Salmonella-infected rats.

BACKGROUND: Glutathione, the main antioxidant of intestinal epithelial cells, is suggested to play an important role in gut barrier function and prevention of inflammation-related oxidative damage as induced by acute bacterial infection. Most studies on intestinal glutathione focus on oxidative stress reduction without considering functional disease outcome. Our aim was to determine whether depletion or maintenance of intestinal glutathione changes susceptibility of rats to Salmonella infection and associated inflammation.Rats were fed a control diet or the same diet supplemented with buthionine sulfoximine (BSO; glutathione depletion) or cystine (glutathione maintenance). Inert chromium ethylenediamine-tetraacetic acid (CrEDTA) was added to the diets to quantify intestinal permeability. At day 4 after oral gavage with Salmonella enteritidis (or saline for non-infected controls), Salmonella translocation was determined by culturing extra-intestinal organs. Liver and ileal mucosa were collected for analyses of glutathione, inflammation markers and oxidative damage. Faeces was collected to quantify diarrhoea. RESULTS: Glutathione depletion aggravated ileal inflammation after infection as indicated by increased levels of mucosal myeloperoxidase and interleukin-1beta. Remarkably, intestinal permeability and Salmonella translocation were not increased. Cystine supplementation maintained glutathione in the intestinal mucosa but inflammation and oxidative damage were not diminished. Nevertheless, cystine reduced intestinal permeability and Salmonella translocation. CONCLUSION: Despite increased infection-induced mucosal inflammation upon glutathione depletion, this tripeptide does not play a role in intestinal permeability, bacterial translocation and diarrhoea. On the other hand, cystine enhances gut barrier function by a mechanism unlikely to be related to glutathione.

Bovine colostrum prevents bacterial translocation in an intestinal ischemia/reperfusion-injured rat model.

This study evaluated whether or not bovine colostrum (BC) is able to treat or prevent intestinal barrier damage, bacterial translocation, and the related systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) in an intestinal ischemia/reperfusion (I/R)-injured rat model. Fifty Sprague-Dawley rats were used. The rats' intestinal I/R injuries were induced by clamping the superior mesenteric artery for 30 minutes. After 3 hours of reperfusion and then twice daily reclamping during the experiment, the experimental group was given BC (4 mL/kg/day) perorally, and the other groups received 0.9% saline and low fat milk (LFM) after intestinal I/R injury. Seventy-two hours later we assessed (1) intestinal damage and intestinal permeability, (2) enteric bacterial count and bacterial translocation, (3) serum albumin, protein, and hepatic enzyme levels, (4) pathologic findings of ileum and lung, (5) activity of oxygen-free radical species, and (6) pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta). Intestinal damage, intestinal permeability, and bacterial translocation to other organs were significantly reduced in rats fed with BC after I/R when compared to rats fed LFM/saline after I/R (P < .05). In the evaluation of acute lung injury, neutrophils were found only in the lungs of the saline-fed group after I/R, and the wet/dry ratio of the lung tissue was significantly reduced in the BC-fed group after I/R compared to other I/R groups. A marked difference was found between LFM/saline-fed groups and BC-fed groups regarding malondialdehyde (P < .05) and pro-inflammatory cytokines (P < .01). In conclusion, BC may have beneficial effects in treating and preventing intestinal barrier damage, bacterial translocation and the related SIRS and MODS in the intestinal I/R-injured rat model.

The effect of Lactobacillus bacteria supplement on sepsis and its complications in patients with acute burns.

Sepsis as a result of bacterial translocation from the gastrointestinal tract (GIT) is a known associate of morbidity and mortality in patients with severe burns. This translocation is influenced by the GIT flora. Oral consumption of Lactobacillus bacteria was previously shown to reduce translocation. We conducted a retrospective cohort study on a series of 56 patients with burns admitted to Soroka University Medical Center in Beer-Sheva, Israel. Those 56 patients included 28 who were given lactobacillus supplements and 28 who were not. The parameters that were compared between the groups evaluated the level of sepsis and its complications. The parameters of morbidity during hospitalization were significantly higher in the treatment group; however, their mortality was lower. That difference in mortality between the groups was not significant as a whole (p=0.071), but it was significant in the subgroup analysis of 41-70% total body surface area burned. In that subgroup there were zero cases of death in the treatment group versus five cases in the control group (p=0.005). Our findings suggest that in acute burns, lactobacillus bacteria food additives may be clinically beneficial in patients with total burned body surface area of 41-70%.

Review article: bacterial translocation in the critically ill--evidence and methods of prevention.

BACKGROUND: Delayed sepsis, systemic inflammatory response syndrome (SIRS) and multiorgan failure remain major causes of morbidity and mortality on intensive care units. One factor thought to be important in the aetiology of SIRS is failure of the intestinal barrier resulting in bacterial translocation and subsequent sepsis. AIM: This review summarizes the current knowledge about bacterial translocation and methods to prevent it. METHODS: Relevant studies during 1966-2006 were identified from a literature search. Factors, which detrimentally affect intestinal barrier function, are discussed, as are methods that may attenuate bacterial translocation in the critically ill patient. RESULTS: Methodological problems in confirming bacterial translocation have restricted investigations to patients undergoing laparotomy. There are only limited data available relating to specific interventions that might preserve intestinal barrier function or limit bacterial translocation in the intensive care setting. These can be categorized broadly into pre-epithelial, epithelial and post-epithelial interventions. CONCLUSIONS: A better understanding of factors that influence translocation could result in the implementation of interventions which contribute to improved patient outcomes. Glutamine supplementation, targeted nutritional intervention, maintaining splanchnic flow, the judicious use of antibiotics and directed selective gut decontamination regimens hold some promise of limiting bacterial translocation. Further research is required.

Modest inflammation enhances diclofenac hepatotoxicity in rats: role of neutrophils and bacterial translocation.

Idiosyncratic adverse drug reactions (IADRs) represent an important human health problem, yet animal models for preclinical prediction of these reactions are lacking. Recent evidence in animals suggests that some IADRs arise from drug interaction with an inflammatory episode that renders the liver sensitive to injury. Diclofenac (DCLF) is one of those drugs for which the clinical use is limited by idiosyncratic liver injury. We tested the hypothesis that modest inflammation triggered in rats by a small dose of lipopolysaccharide (LPS) renders a nonhepatotoxic dose of DCLF injurious to liver. Cotreatment of rats with nonhepatotoxic doses of LPS and DCLF resulted in elevated serum alanine aminotransferase activity and liver histopathologic changes 6 h after DCLF administration. Neither LPS nor DCLF alone had such an effect. Gene array analysis of livers revealed a unique gene expression pattern in the LPS/DCLF-cotreated group compared with groups given either agent alone. Antiserum-induced neutrophil (PMN) depletion in LPS/DCLF-cotreated rats protected against liver injury, demonstrating a role for PMNs in the pathogenesis of this LPS/DCLF interaction. Gut sterilization of LPS/DCLF-treated rats did not protect against liver injury. In contrast, gut sterilization did attenuate liver injury caused by a large, hepatotoxic dose of DCLF, suggesting that hepatotoxicity induced by large doses of DCLF is caused in part by its ability to increase intestinal permeability to endotoxin or other bacterial products. These results demonstrate that inflammation-DCLF interaction precipitates hepatotoxicity in rats and raise the possibility of creating animal models that predict human IADRs.

Confirmation and prevention of intestinal barrier dysfunction and bacterial translocation caused by methotrexate.

When intestinal barrier function is damaged bacterial translocation (BT) can occur. The injury to intestinal barrier function caused by chemotherapy has been investigated in some studies, however, definitive evidence of BT caused by chemotherapy is lacking. The aim of this study was to investigate small intestinal barrier dysfunction and BT and to evaluate the preventive effect of granulocyte colony-stimulating factor (G-CSF) on intestinal barrier dysfunction and BT in a rat model of chemotherapy. Sprague-Dawley rats were treated with methotrexate (MTX; 3.5 mg/kg) for 3 days to induce intestinal barrier dysfunction and BT, gavaged Escherichia coli TG1 labeled with green fluorescent protein for 2 days to track BT, and G-CSF (10 microg/kg) for 4 days to prevent intestinal barrier dysfunction and BT. Intestinal permeability was measured by the urinary excretion rate of lactulose and mannitol following administration by gavage. Representative tissue specimens from the mesenteric lymph nodes, spleen, liver, and kidney were aseptically harvested for bacteria culture in ampicillin-supplemented medium. Light microscopy was performed on intestinal samples. MTX induced significant mucosal and villous atrophy in ileum and significantly increased intestinal permeability. MTX also induced noticeable BT. G-CSF significantly increased the mucosal thickness and villous height of the ileum and decreased intestinal permeability and BT. In conclusion, MTX caused intestinal barrier dysfunction and BT, and G-CSF prevented intestinal barrier dysfunction and BT.

The effect of granulocyte macrophage-colony stimulating factor on bacterial translocation after administration of 5-fluorouracil in rats.

BACKGROUND: After surgical resection for colorectal carcinoma there is a high recurrence rate and, therefore, adjuvant chemotherapy may be useful in some patients. 5-Fluorouracil (5-FU) is the most commonly used chemotherapeutic agent in the management of patients with colorectal cancer. However, gastrointestinal injury induced by chemotherapeutic agents may result in bacterial translocation from the gut into the systemic circulation. Granulocyte macrophage-colony stimulating factor (GM-CSF) may be used to prevent this side effect by means of macrophage activity stimulation. MATERIALS AND METHODS: A total of 45 rats were divided into three groups. Control group received intraperitoneal saline solution, 5-FU and GM-CSF groups received 50 mg/kg/day 5-FU intravenous infusion and GM-CSF group also received 200 ng/day GM-CSF subcutaneously for 6 days. Intestinal tissue was also sampled for pathological examination at day 7. Plasma levels of tumor necrosis factor-alpha and interleukin-6 were determined, bacterial translocation was quantified by lymph node, liver and spleen culture, and plasma endotoxin content was measured. RESULTS: White blood cell counts of the 5-FU rats were significantly lower than in the control and GM-CSF groups (P < 0.01). The plasma endotoxin, tumor necrosis factor-alpha and interleukin-6 levels in the 5-FU and GM-CSF groups were significantly increased at day 7 compared with the control groups (P < 0.01), but these levels were significantly lower in the GM-CSF group compared to the 5-FU group (P < 0.01). 5-FU intervention caused significant increase in the frequencies of bacterial translocation at liver, spleen, mesenteric lymph node, and portal blood. Compared with 5-FU group, GM-CSF decreased the bacterial translocation (P < 0.01). CONCLUSIONS: This study observed that the administration of 5-FU resulted in bacterial translocation. Activation of inflammatory response with GM-CSF is highly effective in prevention of bacterial translocation in 5-FU interventions.

Apoptosis inhibition plays a greater role than necrosis inhibition in decreasing bacterial translocation in experimental intestinal transplantation.

BACKGROUND: During small-bowel transplantation, necrosis and apoptosis are involved in the destruction of intestinal epithelial cells. This study was conducted to assess which mode of cell death plays a greater role as a trigger of the bacterial translocation (BT) associated with intestinal transplantation. METHODS: The following experimental groups were studied: sham, Tx (intestinal transplantation), Tx + poly (ADP-ribose) synthetase (PARS) inhibitor 3-aminobenzamide (3-AB), and Tx + caspase inhibitor Z-VAD-fmk. Histological analysis, caspase-3 activity, DNA fragmentation, and BT were measured in tissue samples after transplantation. RESULTS: During intestinal transplantation, apoptosis and necrosis both increased, showing graft injury and high levels of BT. Rats treated with 3-AB showed histological protection of the transplanted graft and a tendency toward lower BT despite the existence of high apoptosis levels. The rats treated with Z-VAD showed histological protection of the transplanted graft and decreased levels of caspase-3 and DNA fragmentation. The Tx + Z-VAD group showed the lowest levels of BT in all tissues. CONCLUSIONS: In small intestinal transplantation, both apoptosis and cell necrosis give rise to histological injury and BT. Apoptosis inhibition and necrosis inhibition treatments protect intestinal grafts from ischemia/reperfusion injury; Z-VAD supplementation has a greater effect on BT prevention than does administration of the PARS inhibitor 3-AB.

The in vivo assessment of safety and gastrointestinal survival of an orally administered novel probiotic, Propionibacterium jensenii 702, in a male Wistar rat model.

This study aimed to evaluate in vivo gastrointestinal survival and safety of orally administered probiotic bacterium, Propionibacterium jensenii 702, using a male Wistar rat model. A high dose of 10(10) cfu/rat/day of P. jensenii 702 was fed to each rat for 81 days. The repeated dose toxicity and translocation of P. jensenii 702 into rat tissues were evaluated, along with the rat faecal beta-glucuronidase activities and dairy propionibacteria counts. Results showed that P. jensenii 702 had no adverse effect on general health status, body weight gain, visceral organs and faecal beta-glucuronidase activities. No viable cells of P. jensenii 702 were recovered from blood and tissue samples (mesenteric lymph nodes, liver and spleen) of rats, and no treatment-associated illness or death was observed. Faecal dairy propionibacteria counts reached 10(8) cfu/g after 36 days treatment and remained between 10(8)-10(9) cfu/g till the end of 81 days treatment. The results indicate that P. jensenii 702 was able to survive the in vivo gastrointestinal tract transit of rats, with no adverse affects on the animals. However, further human clinical trials are required before strain P. jensenii 702 could be incorporated into food for human consumption as probiotics.

Supplementation and inhibition of nitric oxide synthesis influences bacterial transit time during bacterial translocation in rats.

In the obstructed gut, nitric oxide (NO) may influence intestinal barrier function and translocation of bacteria. By using a novel experimental approach, we investigated the effect of supplementation and inhibition of NO synthesis on the time interval necessary for translocation of green fluorescent protein-transfected Escherichia coli (GFP-uv E. coli) in a rat model of small bowel obstruction. In anesthetized Wistar rats, 4 x 10(8) GFP-uv E. coli were administered into a reservoir of terminal ileum formed by ligature. Animals were randomized to receive either i.v. arginine (10 mg/kg), aminoguanidine (300 mg/kg), L-NAME (25 mg/kg), or saline (control). Translocation of GFP-uv E. coli was assessed using intravital video microscopy. Minimal transit time of translocation was measured as time from injection of GFP-uv E. coli into the gut lumen until bacteria were observed in the lamina submucosa and as time from injection of bacteria into the gut lumen until bacteria were observed in the lamina muscularis propria. Minimal transit times were expressed as mean +/- SD. Bacterial translocation into the submucosa and muscularis propria took 36 +/- 7 min and 81 +/- 9 min, respectively in control animals receiving saline. Aminoguanidine and L-NAME caused a marked delay of minimal transit time into the submucosa (63 +/- 5 min and 61 +/- 7 min, respectively; P < 0.05). Arginine significantly accelerated bacterial translocation into the muscularis propria (61 +/- 9 min, P < 0.05). GFP-uv E. coli were detected on frozen sections of small bowel, mesentery, liver, and spleen 2 h after GFP-uv E. coli administration in all animals. A marked upregulation of inducible NO synthase (NOS) in the obstructed bowel segment was demonstrated on immunohistochemistry. The assessment of a newly defined parameter, minimal bacterial transit time, may serve as an additional functional aspect of intestinal barrier function for pathophysiological and pharmacological studies. Aminoguanidine, L-NAME, and arginine were effective in influencing minimal transit time of E. coli during small bowel obstruction.

Influence of some substances on bacterial translocation in the rat.

An experimental study was planned to determine the effect of zinc, levamisole, misoprostol (prostaglandin(1) analog), and melatonin on the bacterial translocation (BT) that develops in rats after major resection of the liver. To this aim, six groups were formed, each consisting of six rats. Except for the control and sham groups, zinc solution 1 ml/day, (prepared in a way to include zinc sulfate equivalent of 5 mg pure zinc/ml) was given to the zinc groups, levamisole 25 mg/kg/day to the levamisole group, misoprostol 200 mg/kg/day to the misoprostol group, and melatonin 20 mg/kg/day to the melatonin group for 3 days before the operation. After the preoperative administration of 10(10) colony-forming units of Escherichia coli to the experimental groups, the abdomen was opened in the sham group, and only the connections around the liver were cut. In the test groups a 70% liver resection was undertaken. Laparotomy was carried out on all the rats 24 hours after the operation; blood samples were obtained for polymerase chain reaction (PCR) analysis and tissue samples from the terminal ileum for histopathologic examination. PCR results for BT were positive for the control and sham groups, with the difference between these two groups not significant (p > 0.05). A statistically significant decrease was found in the BT of all the treatment groups compared to the control group (p <0.05). The histopathologic examination of terminal ileum in the control group revealed that the inflammatory infiltration was significantly less than that in the other groups (p <0.05).

The effects of pentoxifylline treatment on bacterial translocation after hemorrhagic shock in rats.

Bacterial translocation is thought to be responsible for infectious complications after hemorrhagic shock. The aim of this study was to investigate the effects of pentoxifylline treatment on bacterial translocation in animals subjected to hemorrhagic shock. Thirty-one Wistar albino rats (280-360 g) were divided into three groups: sham (n=10), shock (n=11), and shock-pentoxifylline (n=10). Blood was not withdrawn from sham rats. Shock rats were subjected to 30 min of shock followed by reinfusion of shed blood. Shock/pentoxifylline rats received pentoxifylline after reinfusion of shed blood. After hemorrhage and reinfusion (24 h), the mesenteric lymph nodes, liver, spleen, and blood samples were evaluated using quantitative microbiological techniques, and the numbers of colony-forming units were compared between groups. Cecum was removed to evaluate the bacterial population. Ileum and cecum were examined histologically. The incidence of bacterial translocation was higher in the shocked rats (63%) than in the sham shock rats (10%). Pentoxifylline reduced the incidence of shock-induced bacterial translocation to 0%. Cecal bacterial levels were significantly higher in the shock rats than in the sham and shock/pentoxifylline rats. The histological damage caused by hemorrhagic shock was prevented by pentoxifylline treatment. In conclusion, the hemorrhagic shock triggered translocation of bacteria to the mesenteric lymph nodes, spleen, liver, and blood of rats. Pentoxifylline treatment just after shed blood transfusion significantly attenuated this phenomenon.