The Multi-Component Causes of Late Neonatal Sepsis-Can We Regulate Them?

Elucidating the mechanisms of bacterial translocation is crucial for the prevention and treatment of neonatal sepsis. In the present study, we aimed to evaluate the potential of lactoferrin to inhibit the development of late-onset blood infection in neonates. Our investigation evaluates the role of key stress factors leading to the translocation of intestinal bacteria into the bloodstream and, consequently, the development of life-threatening sepsis. Three stress factors, namely weaning, intraperitoneal administration of Gram-positive cocci and oral intake of Gram-negative rods, were found to act synergistically. We developed a novel model of rat pups sepsis induced by bacterial translocation and observed the inhibition of this process by supplementation of various forms of lactoferrin: iron-depleted (apolactoferrin), iron-saturated (hololactoferrin) and manganese-saturated lactoferrin. Additionally, lactoferrin saturated with manganese significantly increases the Lactobacillus bacterial population, which contributes to the fortification of the intestinal barrier and inhibits the translocation phenomenon. The acquired knowledge can be used to limit the development of sepsis in newborns in hospital neonatal intensive care units.

Zinc Exposure Promotes Commensal-to-Pathogen Transition in Pseudomonas aeruginosa Leading to Mucosal Inflammation and Illness in Mice.

The opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa) is associated gastrointestinal (GI) inflammation and illness; however, factors motivating commensal-to-pathogen transition are unclear. Excessive zinc intake from supplements is common in humans. Due to the fact that zinc exposure enhances P. aeruginosa colonization in vitro, we hypothesized zinc exposure broadly activates virulence mechanisms, leading to inflammation and illness. P. aeruginosa was treated with excess zinc and growth, expression and secretion of key virulence factors, and biofilm production were determined. Effects on invasion, barrier function, and cytotoxicity were evaluated in Caco-2 cells co-cultured with P. aeruginosa pre-treated with zinc. Effects on colonization, mucosal pathology, inflammation, and illness were evaluated in mice infected with P. aeruginosa pre-treated with zinc. We found the expression and secretion of key virulence factors involved in quorum sensing (QS), motility (type IV pili, flagella), biosurfactants (rhamnolipids), toxins (exotoxin A), zinc homeostasis (CzcR), and biofilm production, were all significantly increased. Zinc exposure significantly increased P. aeruginosa invasion, permeability and cytotoxicity in Caco-2 cells, and enhanced colonization, inflammation, mucosal damage, and illness in mice. Excess zinc exposure has broad effects on key virulence mechanisms promoting commensal-to-pathogen transition of P. aeruginosa and illness in mice, suggesting excess zinc intake may have adverse effects on GI health in humans.

Impact of synbiotics treatment on bacteremia induced during neoadjuvant chemotherapy for esophageal cancer: A randomised controlled trial.

BACKGROUND & AIMS: To elucidate the impact of synbiotics on bacterial translocation and subsequent bacteremia during neoadjuvant chemotherapy for esophageal cancer. METHODS: Patients requiring neoadjuvant chemotherapy for esophageal cancer were randomized to receive synbiotics (synbiotics group) or no synbiotics (control group) during chemotherapy. Blood and fecal samples were taken before and after every chemotherapy cycle, and 1 day before surgery. Mesenteric lymph nodes (MLNs) were harvested at laparotomy (MLN-1) and after resection of the tumor (MLN-2). Bacteria in each sample were detected. Fecal microbiota and organic acid concentrations were also determined. The primary endpoint was the detection of bacteria in the blood samples, as well as the incidence of side effects during chemotherapy. The secondary endpoint was the detection rate of bacteria in the MLN samples collected during surgery. RESULTS: The study recruited a total of 42 patients (22 in the control group, 20 in the synbiotics group). Bacteria were detected in 16 of 101 blood samples in the control group, whereas those were detected only 2 of 100 blood samples in the synbiotics group (p < 0.001) during neoadjuvant chemotherapy. Additionally, bacteria were detected in 12 of 34 MLN samples in the control group, whereas no bacteria were detected in 38 MLN samples in the synbiotics group (p < 0.001). Suppression of bacterial translocation was at least partly associated with an increased fecal acetic acid concentration as well as a lowered fecal pH by synbiotics. The incidence rate of grade 3 gastrointestinal toxicity during chemotherapy was lower in the synbiotics group compared to the control group (8/22 vs. 1/20, p = 0.022). CONCLUSIONS: Neoadjuvant chemotherapy for esophageal cancer may induce bacterial translocation and subsequent bacteremia, which can be prevented by synbiotics administration. TRIAL REGISTRATION: The University Hospital Medical Information Network (http://www.umin.ac.jp; registration number ID 000007651).

Altered intestinal microflora and barrier injury in severe acute pancreatitis can be changed by zinc.

To investigate the effect of zinc (Zn) supplementation on intestinal microflora changes and bacterial translocation in rats with severe acute pancreatitis (SAP), the rats were divided into the sham surgery (SS), SAP, SS + Zn, and SAP + Zn groups. Saline (0.1 mL/100g) and 5% sodium taurocholate were injected into the pancreaticobiliary duct of the rats in the SS and SAP + Zn groups, respectively. Intraperitoneal injection of 5 mg/kg Zn was performed immediately after injecting saline or 5% sodium taurocholate into the rats in both groups. Serum amylase and Zn levels, plasma endogenous endotoxin, intestinal permeability, and the positive rate of intestinal bacterial translocation were detected, haematoxylin and eosin (H&E) staining was performed, and the pancreatic tissue scores were calculated for each group. In addition, immunohistochemical (IHC) staining was performed to evaluate the expression of IL-1ß and TNF-α. Real-time fluorescence quantitative PCR was used to quantify the gene copy numbers of Escherichia, Bifidobacterium, and Lactobacillus in the cecum. The levels of amylase and plasma endotoxin in the SAP group were significantly higher than those in the SS and SS + Zn groups. Intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were increased in the SAP group. However, the levels of amylase and plasma endotoxin were decreased as a result of zinc supplementation in the SAP group. The expression of IL-1ß and TNF-α was also reduced to a greater degree in the SAP + Zn group than in the SAP group. Moreover, alleviated intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were found in the SAP + Zn group. The results of real-time quantitative PCR showed that the gene copy number of Escherichia increased with time, and the gene copy numbers of Lactobacillus and Bifidobacterium decreased over time. Zn supplementation prevented the release of TNF-α and IL-1ß, alleviated intestinal permeability and endotoxemia, reduced bacterial translocation, and inhibited changes in pathogenic intestinal flora in rats with SAP.

The effects on bacterial translocation and tissue damage of selenium treatment in an experimental intestina ischaemia-reperfusion model.

BACKGROUND: The free oxygen radicals formed with reperfusion following intestinal ischaemia are extremely toxic for the cells. Glutathione peroxidase, an important enzyme that prevents the formation of reactive oxygen species, requires selenium as a co-factor. This study aims to demonstrate the effects of selenium administration on reducing ischaemia-reperfusion damage. METHODS: In this study, 28 male Wistar rats were separated into four groups. To Groups 3 and 4, sodium selenite at the dose of 10 µg/kg/day was administered intraperitoneally for five days. In Groups 1 and 3, laparotomy was applied, and in Groups 2 and 4, following laparotomy, ischaemia was created by clamping the superior mesenteric artery for 45 mins, then reperfusion was provided for 90 mins. Blood, liver and ileum samples were taken from all the animals for examination of malondialdehyde. For examination of bacterial translocation, liver, spleen and mesenteric lymph node tissue samples were taken. A sample taken from the ileum was examined histopathologically. RESULTS: There was determined to be significantly more bacterial translocation in the mesenteric lymph nodes of the ischaemia-reperfusion group (p<0.05). In the histopathological evaluation, the score in the ischaemia-reperfusion group was significantly higher than the scores in the other groups (p<0.05). Elevated serum, liver and ileum malondialdehyde levels in the ischaemia-reperfusion group were significantly higher than those in the other groups (p<0.05). CONCLUSION: Selenium was seen to have decreased serum and tissue malondialdehyde levels and increased the histopathological damage developing in the intestines with ischaemia-reperfusion and thereby increased bacterial translocation.

Anti-inflammatory and antioxidant effects of the nanocomposite Fullerol decrease the severity of intestinal inflammation induced by gut ischemia and reperfusion.

Intestinal ischemia is a vascular emergency that arises when blood flow to the intestine is compromised. Reperfusion is necessary to restore intestinal function but might lead to local and systemic inflammatory responses and bacterial translocation, with consequent multiple organ dysfunction syndrome (MODS). During reperfusion occurs production of reactive oxygen species. These species contribute to intestinal injury through direct toxicity or activation of inflammatory pathways. Fullerol is a nanacomposite which has been shown to act as reactive oxygen species and reactive nitrogen species (RNS) scavengers. Thus, our aim was to evaluate whether Fullerol confer anti-inflammatory activity during intestinal ischemia and reperfusion (IIR). Intestinal ischemia was induced by total occlusion of the superior mesenteric artery. Groups were treated with vehicle or Fullerol 10 min before reperfusion. Mice were euthanized after 6 h of reperfusion, and small intestines were collected for evaluation of plasma extravasation, leukocyte influx, cytokine production and histological damage. Bacterial translocation to the peritoneal cavity and reactive oxygen and nitrogen species production by lamina propria cells were also evaluated. Our results showed that treatment with Fullerol inhibited bacterial translocation to the peritoneal cavity, delayed and decreased the lethality rates and diminished neutrophil influx and intestinal injury induced by IIR. Reduced severity of reperfusion injury in Fullerol-treated mice was associated with blunted reactive oxygen and nitrogen species production in leukocytes isolated from gut lamina propria and decreased production of pro-inflammatory mediators. Thus, the present study shows that Fullerol is a potential therapy to treat inflammatory bowel disorders associated with bacterial translocation, such as IIR.

No Effect in Alcoholic Hepatitis of Gut-Selective, Broad-Spectrum Antibiotics on Bacterial Translocation or Hepatic and Systemic Inflammation.

INTRODUCTION: In alcoholic hepatitis (AH), translocation of gut bacteria may drive hepatic macrophage activation and systemic inflammation. We investigated the effect of oral non-absorbable, broad-spectrum antibiotic treatment on bacterial translocation and liver and systemic inflammation in AH. METHODS: We consecutively recruited 31 patients with AH. Fourteen were given vancomycin 500 mg, gentamycin 40 mg, and meropenem 500 mg once daily for 7 days. Seventeen patients were a reference group receiving standard-of-care. Circulating markers of bacterial translocation and inflammation were measured at baseline, by day 7 and 90. Gut bacteriome profiling was performed before the intervention and at day 7. RESULTS: At study entry, blood lipopolysaccharide-binding protein was multifold higher than normal, remained unchanged at day 7, but decreased at day 90 (P < 0.001) with no difference between the study groups. The macrophage activation markers sCD163 and sCD206 showed the same pattern (P < 0.001, day 90), still without group differences. The systemic inflammation markers tumor necrosis factor-alpha, interleukin (IL)-6, IL-8, and IL-10 showed similar dynamics without group differences. There was no difference in 90-day mortality (total of 6 deaths) between the groups. The remnant gut bacteriome was markedly diversified by the intervention with growth of bacterial species rare for human flora. DISCUSSION: In patients with AH, gut-targeted antibiotic treatment does not change markers of bacterial translocation and liver and systemic inflammation. This suggests that bacterial translocation is less important once the inflammatory process is established or that bacteriome reduction is less important than composition.

Immunomodulation Through Beta-D-glucan in Chemically-induced Necrotizing Pancreatitis.

BACKGROUND: Although the ability of ß-D-glucan and monophosphoryl lipid A (MPLA) to modulate immune responses has been studied in human primary cells, their effect on sterile inflammation models such as necrotizing pancreatitis has never been investigated. MATERIALS AND METHODS: 85 male New Zealand rabbits were assigned into following groups: A: control, B: pretreatment with ß-D-glucan 3 d before pancreatitis, C: pretreatment with MPLA 3 d before pancreatitis, D: pretreatment with ß-D-glucan and laminarin 3 d before pancreatitis, E: treatment with ß-D-glucan 1 d after pancreatitis, and F: MPLA 1 d after pancreatitis. Pancreatitis was induced by sodium taurocholate injection into the pancreatic duct and parenchyma. Survival was recorded for 21 d. On days 1, 3, and 7, blood was collected for amylase measurement. Peripheral blood mononuclear cells were isolated and stimulated for tumor necrosis factor alpha and interleukin 10 production. Pancreatic necrosis and tissue bacterial load were assessed. RESULTS: 21-d survival was prolonged after pretreatment or treatment with ß-D-glucan; this benefit was lost with laminarin administration. At sacrifice, pancreatic inflammatory alterations were more prominent in the control group. Bacterial load was lower after pretreatment or treatment with ß-D-glucan and MPLA. Tumor necrosis factor alpha production from stimulated peripheral blood mononuclear cells was significantly decreased, whereas interleukin 10 production remained unaltered after pretreatment or treatment with ß-D- glucan. CONCLUSIONS: ß-D-glucan reduces mortality of experimental pancreatitis in vivo. This is mediated through attenuation of cytokine production and prevention of bacterial translocation.

Reversal of Pathogen-Induced Barrier Defects in Intestinal Epithelial Cells by Contra-pathogenicity Agents.

BACKGROUND: Environmental enteropathy (EE) is associated with stunting, impairment of responses to oral vaccines, and other adverse health consequences in young children throughout the developing world. EE is characterized by chronic low-grade intestinal inflammation and disrupted epithelial barrier integrity, partly resulting from dysregulation of tight junction proteins, observed in other enteropathies such as celiac disease. During EE, this dysregulation of tight junction expression amplifies translocation of pathogenic bacteria across the intestinal mucosa. AIMS: The aim was to determine whether enteropathogen-mediated epithelial barrier failure can be ameliorated using contra-pathogenicity therapies. METHODS: Intestinal epithelial barrier damage was assessed in Caco-2 cells incubated with three important enteropathogens identified in EE patients: Enteropathogenic Escherichia coli (EPEC), Citrobacter rodentium (C. rodentium), and Cryptosporidium parvum (C. parvum). Potential therapeutic molecules were tested to detect effects on transepithelial resistance (TER), bacterial translocation (BT), claudin-4 expression, and regulation of the inflammatory cytokine response. RESULTS: All three enteropathogens compared to uninfected cells, reduced TER (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0007), reduced claudin-4 expression, and permitted BT (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0003) through the monolayer. Zinc, colostrum, epidermal growth factor, trefoil factor 3, resistin-like molecule-ß, hydrocortisone, and the myosin light chain kinase inhibitor ML7 (Hexahydro-1-[(5-iodo-1-naphthalenyl)sulfonyl]-1H-1,4-diazepine hydrochloride); ML7) improved TER (up to 70%) and decreased BT (as much as 96%). Only zinc demonstrated modest antimicrobial activity. CONCLUSION: The enteropathogens impaired intestinal-epithelial barrier integrity with dysregulation of claudin-4 and increased bacterial translocation. Enteropathogen-mediated damage was reduced using contra-pathogenicity agents which mitigated the effects of pathogens without direct antimicrobial activity.

Prophylactic and therapeutic supplementation using fructo-oligosaccharide improves the intestinal homeostasis after mucositis induced by 5- fluorouracil.

The beneficial effects of prebiotic, such as fructo-oligosaccharides (FOS), in intestinal inflammation have been demonstrated in several studies. Herein, we evaluate whether joint treatment with FOS, both before and during mucositis, had additional beneficial effects and investigated the mechanisms underlying in the action of FOS on the intestinal barrier. BALB/c mice were randomly divided into five groups: CTR (without mucositis + saline solution), FOS (without mucositis + 6 % FOS), MUC (mucositis + saline solution), PT (mucositis + 6 % FOS supplementation before disease induction), and TT (mucositis + 6 % FOS supplementation before and during disease induction). Mucositis was induced by intraperitoneal injection (300 mg/kg) of 5-fluorouracil (5-FU). After 72 h, the animals were euthanized and intestinal permeability (IP), tight junction, bacterial translocation (BT), histology and morphometry, and immunoglobulin A secretory (sIgA), inflammatory infiltrate, and production of short-chain fatty acids (acetate, butyrate and propionate) were evaluated. The MUC group showed an increase in the IP, BT, and inflammatory infiltrate but a decrease in the tight junction expression and butyrate and propionate levels (P < 0.05). In the PT and TT groups, FOS supplementation maintained the IP, tight junction expression, and propionate concentration within physiologic levels, increased butyrate levels, and reduced BT and inflammatory infiltrate (P < 0.05). Total treatment with FOS (TT group) was more effective in maintaining histological score, morphometric parameters, and sIgA production. Thus, total treatment (prophylactic and therapeutic supplementation) with FOS was more effective than pretreatment alone, in reducing 5-FU-induced damage to the intestinal barrier.

Effect of Baicalin on Bacterial Secondary Infection and Inflammation Caused by H9N2 AIV Infection in Chickens.

H9N2 subtype avian influenza virus (H9N2 AIV) is a low pathogenic virus that is widely prevalent all over the world. H9N2 AIV causes immunosuppression in the host and often leads to high rates of mortality due to secondary infection with Escherichia. Due to the drug resistance of bacteria, many antibiotics are not effective in the treatment of secondary bacterial infection. Therefore, the purpose of this study is to find effective nonantibiotic drugs for the treatment of H9N2 AIV infection-induced secondary bacterial infection and inflammation. This study proves, for the first time, that baicalin, a Chinese herbal medicine, can regulate Lactobacillus to replace Escherichia induced by H9N2 AIV, so as to resolve the intestinal flora disorder. In addition, baicalin can effectively prevent intestinal bacterial translocation of SPF chickens' post-H9N2 AIV infection, thus inhibiting secondary bacterial infection. Furthermore, baicalin can effectively treat H9N2 AIV-induced inflammation by inhibiting intestinal structural damage, inhibiting damage to ileal mucus layer construction and tight junctions, improving antioxidant capacity, affecting blood biochemical indexes, and inhibiting the production of inflammatory cytokines. Taken together, these results provide a new theoretical basis for clinical prevention and control of H9N2 AIV infection-induced secondary bacterial infection and inflammation.

Macrophage Deficiency Makes Intestinal Epithelial Cells Susceptible to NSAID-Induced Damage.

OBJECTIVES: In Crohn's disease (CD), the mechanisms underlying the regulation by granulocyte-macrophage colony-stimulating factor (GM-CSF) of mucosal barrier function in the ileum are unclear. We analyzed the molecular mechanisms underlying the regulation by GM-CSF of the mucosal barrier function. METHODS: We examined the role of GM-CSF in the intestinal barrier function in CD at the molecular-, cellular-, and animal-model levels. RESULTS: Macrophages directly secreted GM-CSF, promoting intestinal epithelial proliferation and inhibiting apoptosis, which maintained intestinal barrier function. Macrophages were absent in NSAID-induced ileitis, causing GM-CSF deficiency, increasing the apoptosis rate, decreasing the proliferation rate, increasing inter- and paracellular permeabilities, decreasing the TJP levels, and reducing the numbers of mesenteric lymph nodes, memory T cells, and regulatory T cells in Csf1op/op transgenic mice. CONCLUSIONS: GM-CSF is required for the maintenance of intestinal barrier function. Macrophages directly secrete GM-CSF, promoting intestinal epithelial proliferation and inhibiting apoptosis.

Gut mucosa in the rats exposed temporary mechanical obstruction fed with probiotic.

BACKGROUND: Created a model in the rats, to prevent mucosal damage and related effects in the patients, who were operated due to mechanical obstruction. Some groups fed fodder with probiotics, some groups fed with standard fodder. It is objected that the damage of gut mucosa and related effects on how to expose the differences of the groups. METHODS: In this study, 48 female Wistar-albino type rats are separated into five groups randomly. In the first operation, rats' terminal ileum was tied up with silk except for the control group. Two groups 24, the other two groups 48 hours later operated again and terminal ileum obstructions were removed. During that time, each one of those 24 and 48 hours of obstructed groups were fed with probiotic. Twenty-four hours later, the control group and other groups were operated for the third time for sampling. Terminal ileum, liver, spleen, MLN (Mesenteric lymph node) and blood samples were taken. RESULTS: The research group, which was obstructed and fed with probiotics during 48 hours, was significantly observed in increased mucosa cell loss and mucosal edema. Bacterial translocation was found more common in groups without probiotics. Tissue GR (Glutathione reductase) and erythrocyte CAT (Catalase) were lower in the group of 24 hours obstructed and given probiotics. CONCLUSION: The findings suggest that the high rate of mucosal edemas in the groups that are fed with probiotics can be seen as damage, but we think that probiotics are consonant with the strength of the mucosal barrier. Thus, in the groups fed with probiotics, it is possible that bacterial translocation is seen less, and some antioxidative enzymes are found less. Further studies are needed to investigate the benefits of probiotics in patients operated for obstruction.

Transient neonatal antibiotic exposure increases susceptibility to late-onset sepsis driven by microbiota-dependent suppression of type 3 innate lymphoid cells.

Extended early antibiotic exposure in the neonatal intensive care unit is associated with an increased risk for the development of late-onset sepsis (LOS). However, few studies have examined the mechanisms involved. We sought to determine how the neonatal microbiome and intestinal immune response is altered by transient early empiric antibiotic exposure at birth. Neonatal mice were transiently exposed to broad-spectrum antibiotics from birth for either 3- (SE) or 7-days (LE) and were examined at 14-days-old. We found that mice exposed to either SE or LE showed persistent expansion of Proteobacteria (2 log difference, P < 0.01). Further, LE mice demonstrated baseline translocation of E. coli into the liver and spleen and were more susceptible K. pneumoniae-induced sepsis. LE mice had a significant and persistent decrease in type 3 innate lymphoid cells (ILC3) in the lamina propria. Reconstitution of the microbiome with mature microbiota by gavage in LE mice following antibiotic exposure resulted in an increase in ILC3 and partial rescue from LOS. We conclude that prolonged exposure to broad spectrum antibiotics in the neonatal period is associated with persistent alteration of the microbiome and innate immune response resulting in increased susceptibility to infection that may be partially rescued by microbiome reconstitution.

Effect of poorly absorbable antibiotics on hepatic venous pressure gradient in cirrhosis: A systematic review and meta-analysis.

BACKGROUND: The effects of poorly/non-absorbable antibiotics on hepatic venous pressure gradient (HVPG) are debated. AIM: To analyze the effects of rifaximin or norfloxacin on HVPG and on markers of bacterial translocation and proinflammatory cytokines. METHODS: We performed a systematic search of randomized clinical trials (RCTs) involving patients with cirrhosis and portal hypertension, assessing the effect of rifaximin or norfloxacin vs control on HVPG. Pooled analyses were based on random-effects models, heterogeneity was assessed by Cochran's Q, I2 statistic and subgroup analyses. RESULTS: Five studies (215 patients) were included. Risk of bias was high in three. We found no significant differences using antibiotics versus control. The summary mean difference in HVPG was of -0.55 mmHg (95%CI:-1.52, 0.42; P = 0.27), with moderate heterogeneity (P = 0.15; I2 = 40%). RCTs with longer therapy (60-90 days) used non-selective-beta-blockers (NSBB) in both antibiotics and control arms. Subgroup analysis showed a significantly greater reduction in HVPG in the combination arm over controls (mean difference -1.46 mmHg [95%CI: -2.63, -0.28; P = 0.01]) with no heterogeneity (P = 0.46; I2 = 0%). Serum lipopolysaccharide-binding protein (LBP) significantly decreased with antibiotics, but with high heterogeneity (P < 0.001; I2 = 92%). CONCLUSIONS: Rifaximin or norfloxacin did not significantly reduce HVPG in patients with cirrhosis and portal hypertension. Studies using antibiotic for longer periods on top of NSBB showed a significant decrease in HVPG.

Ginkgolide-A attenuates bacterial translocation through activating PXR and improving antimicrobial peptide Reg 3A in experimental cirrhosis.

BACKGROUND AND AIMS: Bacterial translocation (BT) is strongly associated with disease progression and poor outcome in cirrhotic patients. The role of Pregnane X receptor (PXR) in regulating bacterial translocation in cirrhosis is unknown. We previously showed that Ginkgolide-A (GA), a natural PXR ligand, attenuated BT in cirrhotic mice by abrogating inflammation along the gut-liver-axis, and by protecting small intestinal tight junctions (TJ). Here, we aimed to investigate the effect of GA in activating PXR and associated antimicrobial peptides (AMPs) in regulating BT in experimental cirrhosis. METHODS: Male Swiss albino mice were administered CCl4 (0.5 mL/kg body-weight, i.p twice a week) for 12 consecutive weeks. After the 12th week, mice were randomized and administered with GA (100-mg/kg body-weight, oral) every-day for 2 weeks. At termination, blood, gut and liver tissues were collected for molecular studies. RESULTS: GA treatment to cirrhotic mice significantly increased the expression of small intestinal PXR and Regenerating family member 3 alpha (Reg3A), which were otherwise reduced in CCl4 cirrhotic mice. Moreover, compared to naive mice a significantly reduced Lactobacillus, and increased Bacteroides and Enterococcus 16s rRNA levels were observed in the small intestine and liver of cirrhotic mice. Treatment with GA to cirrhotic mice significantly reduced intestinal overgrowth and translocation of Enterococcus and Bacteroides to the liver. Furthermore, GA treatment significantly attenuated intestinal permeability and BT marker soluble-CD14 (sCD14), which were increased in CCl4 cirrhotic mice. CONCLUSION: The study showed for the first time that, GA treatment to cirrhotic rodents attenuates BT, by improving PXR and Reg3A expression.

Bacteroides fragilis prevents Salmonella Heidelberg translocation in co-culture model mimicking intestinal epithelium.

Salmonella Heidelberg is one of the most common serovar causing foodborne illnesses. To limit the development of digestive bacterial infection, food supplements containing probiotic bacteria can be proposed. Commensal non-toxigenic Bacteroides fragilis has recently been suggested as a next-generation probiotic candidate. By using an original triple co-culture model including Caco-2 cells (representing human enterocytes), HT29-MTX (representing mucus-secreting goblet cells), and M cells differentiated from Caco-2 by addition of Raji B lymphocytes, bacterial translocation was evaluated. The data showed that S. Heidelberg could translocate in the triple co-culture model with high efficiency, whereas for B. fragilis a weak translocation was obtained. When cells were exposed to both bacteria, S. Heidelberg translocation was inhibited. The cell-free supernatant of B. fragilis also inhibited S. Heidelberg translocation without impacting epithelial barrier integrity. This supernatant did not affect the growth of S. Heidelberg. The non-toxigenic B. fragilis confers health benefits to the host by reducting bacterial translocation. These results suggested that the multicellular model provides an efficient in vitro model to evaluate the translocation of pathogens and to screen for probiotics that have a potential inhibitory effect on this translocation.

Daily variations of gut microbial translocation markers in ART-treated HIV-infected people.

BACKGROUND: Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affected by food intake and circadian rhythms. However, daily variations of these markers are not characterized yet in PLWH. Herein, we assessed the variation of these markers over 24 h in PLWH receiving antiretroviral therapy (ART) in a well-controlled environment. METHODS: As in Canada, PLWH are predominantly men and the majority of them are now over 50 years old, we selected 11 men over 50 receiving ART with undetectable viremia for more than 3 years in this pilot study. Blood samples were collected every 4 h over 24 h before snacks/meals from 8:00 in the morning to 8:00 the next day. All participants consumed similar meals at set times, and had a comparable amount of sleep, physical exercise and light exposure. Plasma levels of bacterial lipopolysaccharide (LPS) and fungal (1→3)-ß-D-Glucan (BDG) translocation markers, along with markers of intestinal damage fatty acid binding protein (I-FABP) and regenerating islet-derived protein-3α (REG3α) were assessed by ELISA or the fungitell assay. RESULTS: Participants had a median age of 57 years old (range 50 to 63). Plasma levels of BDG and REG3α did not vary significantly over the course of the study. In contrast, a significant increase of LPS was detected between 12:00 and 16:00 (Z-score: - 1.15 ± 0.18 vs 0.16 ± 0.15, p = 0.02), and between 12:00 and 24:00 (- 1.15 ± 0.18 vs 0.89 ± 0.26, p < 0.001). The plasma levels of I-FABP at 16:00 (- 0.92 ± 0.09) were also significantly lower, compared to 8:00 the first day (0.48 ± 0.26, p = 0.002), 4:00 (0.73 ± 0.27, p < 0.001) or 8:00 on secondary day (0.88 ± 0.27, p < 0.001). CONCLUSIONS: Conversely to the fungal translocation marker BDG and the gut damage marker REG3α, time of blood collection matters for the proper evaluation for LPS and I-FABP as markers for the risk of inflammatory non-AIDS co-morbidities. These insights are instrumental for orienting clinical investigations in PLWH.

MitoQ Modulates Lipopolysaccharide-Induced Intestinal Barrier Dysfunction via Regulating Nrf2 Signaling.

BACKGROUND: Gut barrier dysfunction with alterant mucosal permeability during sepsis is a challenge problem in clinical practice. Intestinal epithelial cells (IECs) are strongly involved in mucosal oxidative stress and inflammatory response. The current study aimed at investigating the effect of MitoQ, a mitochondrial targeted antioxidant, in the treatment of intestinal injury and its potential mechanism during sepsis. METHODS: 30 minutes before sepsis induction by lipopolysaccharide (LPS) treatment, mice were treated with MitoQ. Intestinal histopathology, mucosal permeability, inflammatory cytokines, and mucosal barrier proteins were evaluated in the present study. RESULTS: MitoQ pretreatment significantly decreased the levels of plasma diamine oxidase, D-lactate, and intestinal histological damage and markedly restored the levels of tight junction proteins (ZO-1 and occludin) following LPS challenge. Furthermore, MitoQ inhibited the LPS-induced intestinal oxidative stress and inflammatory response, evidenced by increased levels of intestinal superoxide dismutase and glutathione, and decreased levels of intestinal IL-1, IL-6, TNF-α, and nitric oxide levels. Mechanically, we found that MitoQ inhibited the oxidative stress via activating nuclear factor E2-related factor 2 (Nrf2) signaling pathway and its downstream antioxidant genes, including HO-1, NQO-1, and GCLM. CONCLUSIONS: MitoQ exerts antioxidative and anti-inflammatory effects against sepsis-associated gut barrier injury by promoting Nrf2 signaling pathway.

Novel Forms of Immunomodulation for Cancer Therapy.

In recent years immunotherapy has provided new hope for cancer patients. However, some patients eventually relapse. Immunological responses are thought to underlie the long-term effects of conventional or targeted therapies. Whether this influence emerges from direct effects on cancer cells through immunogenic cell death (ICD) or by modulating the immune environment requires further clarification. ICD-related molecular mechanisms are also shared by cell-intrinsic defense responses that combat foreign intrusions. Indeed, we could potentially mimic and harness these processes to improve cancer immunogenicity. In addition, the microbiome is materializing as a missing factor in the cancer-immune therapy axis. The emerging idea of manipulating the gut microbiota to improve responses to anticancer therapy is becoming increasingly popular, but further clinical authentication is needed.