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Balb/c mice were transfused with .2 mL of C3H/HeJ mouse blood. 5 days later, the mice were gavaged with 10(10) 14C-labeled Escherichia coli, and a 20% full thickness flame burn was inflicted. Additional animals were treated with enisoprost (prostaglandin E1 (PGE1) analog) 200 micrograms/kg/day orally for 3 days before burn. Bacterial translocation was determined by both radionuclide counts (dpm) and viable colony counts 24 h post burn. Neutrophil accumulation was evaluated by the measurement of myeloperoxidase (MPO) in the liver. In addition, splenic macrophages were separated and cultured for 24 h with or without 10 micrograms/mL of LPS. Tumor necrosis factor, interleukin-1 (IL-1), IL-6, and PGE2 were measured in the cell culture supernatants. Consistent with previous work, enisoprost significantly reduced translocation. MPO in the liver was significantly greater in the control group compared to the enisoprost group. There was a significant correlation between MPO content and the degree of bacterial translocation (p < .05). Lipopolysaccharide-stimulated macrophage production of IL-1, IL-6, and PGE2 were significantly greater in the enisoprost group.

The relationship between hypermetabolism and bacterial translocation was investigated in guinea pigs receiving a 40% burn. Animals were infused intragastrically with a complete enteral diet or Ringer's solution for 48 h, given 10(10) 14C-labeled Escherichia coli intragastrically, and killed 4 h later. Resting metabolic expenditure (RME), translocation (dpm of the 14C-labeled E. coli) to the portal blood and ileal mucosa, plasma cortisol, and urinary vanillylmandelic acid (VMA) were determined. Enterally fed animals had significantly lower RME, cortisol, VMA, and dpm, but higher mucosal and body weight than the Ringer's group. Disintegrations per minute (dpm) in the blood were positively correlated with RME (r = 0.856), cortisol (r = 0.872), VMA (r = 0.759), and dpm mucosa (r = 0.836) and inversely correlated with mucosal weight (r = -0.883). We conclude that bacterial translocation is reduced by early feeding and is an important cause of hypermetabolism and stress hormone production after burn injury.

The aim of this study was to evaluate the ability of basic fibroblast growth factor (bFGF) and sucralfate to prevent bacterial translocation after burn injury. Four groups of Balb/c mice (n = 10/group) were treated by gavage with bFGF (10 micrograms/kg/d), sucralfate (15 mg/kg/d), bFGF plus sucralfate, or saline for 4 days prior to receiving a gavage with 1 x 10(10) 14C-radiolabeled Escherichia coli and a 20% full-thickness burn. Four hours after burn, the mesenteric lymph nodes, liver, spleen, and blood were harvested aseptically. For each tissue, the number of viable bacteria and radionuclide counts of the translocated 14C-labeled E. coli were measured, and the percentage of translocated organisms that remained alive was calculated. The results indicated that treatment with either bFGF or sucralfate alone had a partial effect on translocation, whereas the combined treatment with bFGF plus sucralfate significantly decreased the magnitude of translocation in all tested tissues (p < 0.05, ANOVA), which was associated with complete preservation of gut mucosal integrity. None of the treatments affected the ability of the host to kill translocated bacteria when the results were compared with those of the controls. The additive effect of the combined therapy may be due to the high affinity of sucralfate for bFGF, decreasing the degradation of bFGF by gastric acid.

The aim of this study was to investigate the ability of two prostaglandin E1 (PGE1) analogues, misoprostol and enisoprost, to alter bacterial translocation following burn injury. Balb/c mice were treated with misoprostol (n = 36) or enisoprost (n = 36) for 3 days with different doses (20 or 200 micrograms/kg/day) prior to receiving a 20% full-thickness burn and simultaneous gavage with 1 x 10(10) 14C-Escherichia coli. Animals were sacrificed 4 and 24 hr postburn, and blood, peritoneal fluid, mesenteric lymph nodes, spleen, liver, and lungs were harvested aseptically. Radionuclide counts, number of viable bacteria, and percentage of translocating bacteria remaining alive in each tissue suggested that the high doses of misoprostol or enisoprost decreased the magnitude of 14C-E. coli translocation, while the low dose of both drugs enhanced bacterial clearance. Therefore, both misoprostol and enisoprost reduce bacterial translocation, and modulate bacterial clearance in a dose-dependent manner.

The process of microbial translocation was studied using Candida albicans, Escherichia coli, or endotoxin instilled into Thiry-Vella loops of thermally injured guinea pigs and rats. Translocation of C. albicans occurred by direct penetration of enterocytes by a unique process different from classical phagocytosis. Translocation between enterocytes was not observed. Internalization was associated with a disturbance of the plasma membrane and brush border, but most internalized organisms were not surrounded by a plasma membrane. Passage of the candida into the lamina propria appeared to be associated with disruption of the basal membrane with extrusion of cytoplasm of the cell and candida. Organisms in the lamina propria were commonly phagocytized by macrophages but also were found free in lymphatics and blood vessels. Translocation of E. coli and endotoxin also occurred directly through enterocytes rather than between them, but translocated endotoxin diffused through the lamina propria and muscular wall of the bowel wall by passing between rather than through the myocytes. These descriptive phenomena provide new insight into the role of the enterocyte and intestinal immune cells in the translocation process.

To assess the effect of four regimens of antibiotics (compared with a control regimen of distilled water) given orally on gut decontamination, bacterial translocation, and mortality in acute necrotising pancreatitis in mice

Glutamine has been shown to be an important dietary component for the maintenance of gut metabolism. The purpose of this study was to assess the potential benefit of glutamine-enriched diets on experimental gut-derived sepsis.BALB/c mice were fed either 2% glutamine-supplemented or 1% glycine-supplemented (near-isonitrogenous control) AIN-76A diets. Control mice received either nonsupplemented AIN-76A or regular Purina Rodent Laboratory Mouse Chow 5001 diets. After 10 days of feeding, the mice were transfused with allogeneic blood (from C3H/HeJ mice), and the feeding protocols were continued for an additional 5 days. The mice then underwent gavage with 10(10) Escherichia coli labeled with either indium-111 oxine or [14C]glucose followed immediately by a 20% burn injury. Some mice were observed 10 days postburn for survival rates. Others were killed 4 hours after burn, and the mesenteric lymph nodes, liver, and spleen were harvested to determine radionuclide and bacterial colony counts. The percentages of viable translocated E coli were also calculated.Mice fed glutamine-enriched diets had a lower degree of translocation (as measured by both radionuclide and bacterial counts) to the tissues than did the other groups and had an improvement in the ability to kill translocated E coli (as measured by the percentage of viable bacteria). Survival was significantly higher in the group fed 2% glutamine (81%) compared with the groups fed 1% glycine (36%), AIN-76A (35%), and Purina Rodent Laboratory Mouse Chow 5001 (36%) diets (p.004).Glutamine-supplemented enteral diets may exert important benefits in preventing gut-origin sepsis after trauma.

OBJECTIVE: The effect of arginine on survival rates and host defense mechanisms was studied using two clinically relevant models of infection that included transfusion-induced immunosuppression. SUMMARY BACKGROUND DATA: Dietary arginine will improve resistance to infection but its role in transfusion-induced immunosuppression and bacterial translocation (gut-derived sepsis) has not been defined. METHODS: Balb/c mice were fed for 10 days with either a defined AIN-76A diet, an AIN-76A diet supplemented with 2% arginine, an AIN-76A diet supplemented with 4% glycine, or standard laboratory chow. In most experiments, the mice were then transfused with allogeneic blood and allowed to feed for an additional 5 days before undergoing either cecal ligation and puncture (CLP) or gavage with 10(10) Escherichia coli and a 20% burn injury. Additional animals fed with the arginine supplemented diet were treated with the nitric oxide inhibitor N omega-Nitro-L-arginine (NNA) before gavage and burn. The effect of these diets and NNA on the degree of translocation of 14C-radiolabeled E. coli from the intestine and the ability of the host to kill translocated organisms was also investigated. Mice were fed and received transfusion, gavage, and burn as above. Mesenteric lymph nodes (MLN), liver and spleen were harvested 4 hours postburn. RESULTS: Survival after CLP was 56% in the arginine-supplemented group versus 28% in the AIN-76A group and 20% in the chow group (p < 0.02). After gavage and burn, survival was 100% in the arginine-supplemented group versus 50% in both the glycine-supplemented and chow groups and 35% in the AIN-76A group (p < 0.01). In animals receiving the arginine-supplemented diet, treatment with NNA decreased survival from 95% to 30.5% (p < 0.0001). Greater translocation, as measured by radionuclide counts, was observed to the MLN of the AIN-76A group. However, there was no difference in translocation to the liver and spleen related to dietary group. Quantitative colony counts and the calculated percentage of remaining viable bacteria showed that the ability to kill translocated organisms was significantly enhanced in animals receiving arginine. Treatment with NNA reversed the beneficial effects of arginine on immune defense. CONCLUSIONS: The benefit of arginine appears to be mediated by improved bactericidal mechanisms via the arginine-nitric oxide pathway.

Bacterial translocation and related mortality rates were examined in previously transfused BALB/c mice that were gavaged with 14C radioisotope-labeled Escherichia coli before inflicting a 20% full-thickness flame burn. Radionuclide counts were measured in blood obtained by retro-orbital puncture 4 hours postburn, and survival was recorded for 10 days. Radionuclide counts in the blood correlated well with both radionuclide counts and numbers of viable bacterial in the tissues. Survivors had significantly less bacterial translocation as evidenced by blood radionuclide counts compared with nonsurvivors, and there was a significant inverse correlation between the degree of translocation and the length of survival. In the next experiment, the prostaglandin E (PGE) analogs misoprostol, enisoprost, or 16,16-dimethyl PGE2 were administered to transfused animals for 3 days before burn. Prostaglandin E analogs significantly reduced bacterial translocation as measured by blood radionuclide counts 4 hours postburn and improved survival. The data demonstrate that the intensity of bacterial translocation after burn injury is significantly associated with subsequent death. Improvement of survival by PGE analogs is associated with decreased bacterial translocation.

The present investigation was performed to study the kinetics of tissue distribution and deposition of Escherichia coli and endotoxin translocating from the intestine after thermal injury. Escherichia coli was grown in the presence of 14C glucose and both labeled bacteria and endotoxin prepared from the labeled bacteria were used as translocation probes. Escherichia coli (10(8) to 10(10) bacteria) and E. coli endotoxin (100 micrograms per animal) were gavaged into the stomach immediately before a 30% burn injury was inflicted in mice. Animals were killed 1, 4 and 24 hours after burn injury. Translocation occurred extensively within 1 hour after burn injury. Expressed as amount of radioactivity per gram of tissue, translocation was greatest in the mesenteric lymph node (MLN) followed by spleen, lung, and liver. Translocation of endotoxin was similar to translocation of intact bacteria, with the exception that less radioactivity could be found in the peritoneal cavity and more in the liver. Both intact E. coli and endotoxin translocated directly through the intact bowel wall. Killing of bacteria was greatest in the MLN and spleen, approximating 95% to more than 99% of translocating bacteria. Killing efficiency was lowest in the lungs. It is concluded that estimation of translocation by viable bacterial counts in tissues grossly underestimates the extent of translocation of bacteria and ignores the extent of translocation of endotoxin. Translocation of endotoxin may have biologic significance that is independent of and in addition to translocation of intact bacteria.

Prednisone may be immunosuppressive and dehydroepiandrosterone may stimulate the immune response, but their effect on gut-origin sepsis caused by bacterial translocation has not been studied. Balb/c mice were treated orally with prednisone (1 or 10 mg/kg/day) or saline for 4 days before receiving gavage with 10 (10) 14 C-labeled Escherichia coli and a 20% thermal injury. Mice were transfused with allogeneic blood and given dehydroepiandrosterone (5 or 25 mg/kg/day) or vehicle subcutaneously for 4 days before bacterial gavage and thermal injury. Some groups in each experiment were observed 10 days for mortality and others were sacrificed 4 hr postburn to measure translocation and survival of translocated bacteria. Survival in prednisone treated animals was 25% (10 mg/kg/day) and 75% (1 mg/kg/day) versus 80% for controls. Following dehydroepiandrosterone administration, survival was 72% (25 mg/kg/day/group) and 30% (5 mg/kg/day/group) versus 16% for controls. High dose prednisone increased bacterial translocation to the intestinal wall and mesenteric lymph nodes and greatly impaired killing of translocated E. coli. In contrast, dehydroepiandrosterone (25 mg/kg) did not affect translocation but significantly improved bacterial killing. Prednisone and dehydroepiandrosterone exert opposite effects during gut-derived sepsis.

The effect of dietary lipids on bacterial translocation, killing of translocated organisms and host survival was studied in a burned animal model. Balb/c mice were fed with one of the three experimental AIN-76A diets (containing 15% of energy from fish oil, safflower oil or a 50:50 mixture), AIN- 76A without added lipids or a nonpurified stock diet. All animals were transfused on day 10. On day 15, the animals were gavaged with 10 l° 14C radiolabelled Escherichia coli and given a 20% burn injury. Survival was 84% in the fish oil group versus 36% in the safflower oil and 50:50 diet groups, and 25% and 20% in the two control groups (P< 0.0001). The numbers of viable translocating bacteria were reduced in all tested organs in the fish oil groups compared to the other groups. It is concluded that a diet enriched in fish oil has beneficial effects during gut-derived sepsis.

B. fragilis and E. coli were labeled with tritiated ( 3 H) thymidine, and 10 10 of each were given separately by gavage in Balb/c mice immediately before a 20% burn injury was inflicted. Control groups received gavage with 3 H-B. fragilis or 3 H-E. coli without burn. Four hours after burn or gavage was administered, the animals were killed, and the radionuclide and colony counts were determined in the mesenteric lymph nodes, liver, and spleen. Additional groups of mice receiving gavage (B. fragilis or E. coli) and burn were observed for 10 days to study survival. The results showed that 3 H-B. fragilis translocated to a greater extent than 3 H-E. coli but that fewer B. fragilis than E. coli survived in tissues. Survival was 86% for animals challenged with B. fragilis versus 53% for animals challenged with E. coli. It is concluded that in this model B. fragilis translocates extensively after burn injury and that survival is closely related to the destruction of translocated bacteria

OBJECTIVE: The effect of recombinant murine granulocyte macrophage colony-stimulating factor (rmGM-CSF) on survival and host defense was studied using two clinically relevant models of infection that included transfusion-induced immunosuppression. SUMMARY BACKGROUND DATA: Granulocyte macrophage colony-stimulating factor improves resistance in several models of infection, but its role in transfusion-induced immunosuppression and bacterial translocation (gut-derived sepsis) has not been defined. METHODS: Balb/c mice were treated with 100 ng of rmGM-CSF or placebo for 6 days in a model of transfusion, burn, and gavage, or cecal ligation and puncture (CLP). Translocation was studied in the first model. RESULTS: Survival after transfusion, burn, and gavage was 90% in rmGM-CSF-treated animals versus 35% in the control group (p < 0.001). After CLP, survival was 75% in the rmGM-CSF group versus 30% in the control group (p = 0.01). Less translocation and better killing of bacteria was observed in the tissues in animals treated with rmGM-CSF. CONCLUSION: The ability of rmGM-CSF to improve gut barrier function and enhance killing of translocated organisms after burn injury-induced gut origin sepsis was associated with improved outcome. Granulocyte macrophage colony-stimulating factor also improved survival after CLP.

To investigate the effect of: a) starvation during the preburn period and b) immediate postburn enteral nutrition on the permeability of the gut to microorganisms and the ability of the host to kill translocated bacteria.Prospective, randomized, experimental trials.Laboratory.Balb/c mice and Hartley guinea pigs.In the first experiment, mice were starved for 0, 6, 12, 18, or 24 hrs before receiving gavage with 10(10) 14C-labeled Escherichia coli and a 20% burn injury. In the second experiment, guinea pigs received a 40% burn injury and were randomized to receive a complete enteral diet (175 kcal/kg/day) or infusion of an equal volume of lactated Ringer's solution via a previously placed gastrostomy for 6, 24, or 48 hrs. After each feeding period, 10(10) 14C Escherichia coli were infused intragastrically. In both experiments, the animals were killed 4 hrs after gavage, and mesenteric lymph nodes, spleen, liver, lungs, peritoneal fluid, and blood were harvested aseptically.For each tissue or fluid, the number of viable E. coli and radionuclide counts of the 14C E. coli were measured and the percentage of translocated bacteria that remained alive was calculated.In mice, 18 and 24 hrs of preburn starvation increased translocation only to the mesenteric lymph nodes, but it also enhanced bacterial killing in all tested tissues. Guinea pigs that were fed enterally for 6, 24, and 48 hrs postburn had significantly lower bacterial translocation in all tissues compared with animals infused with lactated Ringer's solution. Additionally, enhanced killing of translocating organisms was observed after 24 and 48 hrs of feeding.Starvation preburn has different consequences than starvation postburn on translocation and bacterial killing. Postburn enteral nutrition decreases the load of viable bacteria in the tissues via a double mechanism: an initial decreased translocation and a subsequent improved ability to kill bacteria that do translocate.