Novel pathomechanism for spontaneous bacterial peritonitis: disruption of cell junctions by cellular and bacterial proteases.

OBJECTIVE: Spontaneous bacterial peritonitis (SBP) is a life-threatening complication of liver cirrhosis with a 1-year mortality of 66%. Bacterial translocation (BT) from the intestine to the mesenteric lymph nodes is crucial for the pathogenesis of SBP. DESIGN: Since BT presupposes a leaky intestinal epithelium, the integrity of mucus and epithelial cell junctions (E-cadherin and occludin) was examined in colonic biopsies from patients with liver cirrhosis and controls. SBP-inducing Escherichia coli (E. coli) and Proteus mirabilis (P. mirabilis) were isolated from ascites of patients with liver cirrhosis and co-cultured with Caco-2 cells to characterise bacteria-to-cell effects. RESULTS: SBP-derived E. coli and P. mirabilis led to a marked reduction of cell-to-cell junctions in a dose-dependent and time-dependent manner. This effect was enhanced by a direct interaction of live bacteria with epithelial cells. Degradation of occludin is mediated via increased ubiquitination by the proteasome. Remarkably, a novel bacterial protease activity is of pivotal importance for the cleavage of E-cadherin. CONCLUSION: Patients with liver cirrhosis show a reduced thickness of colonic mucus, which allows bacteria-to-epithelial cell contact. Intestinal bacteria induce degradation of occludin by exploiting the proteasome of epithelial cells. We identified a novel bacterial protease activity of patient-derived SBP-inducing bacteria, which is responsible for the cleavage of E-cadherin structures. Inhibition of this protease activity leads to stabilisation of cell junctions. Thus, targeting these mechanisms by blocking the ubiquitin-proteasome system and/or the bacterial protease activity might interfere with BT and constitute a novel innovative therapeutic strategy to prevent SBP in patients with liver cirrhosis.

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.

Paracellular Pathway-Mediated Mycoplasma hyopneumoniae Migration across Porcine Airway Epithelial Barrier under Air-Liquid Interface Conditions.

Mycoplasma hyopneumoniae is an important respiratory pathogen of pigs that causes persistent and secondary infections. However, the mechanisms by which this occurs are unclear. In this study, we established air-liquid interface culture systems for pig bronchial epithelial cells (ALI-PBECs) that were comparable to the conditions in the native bronchus in vivo We used this ALI-PBECs model to study the infection and migration characteristics of M. hyopneumoniaein vitro Based on the results, we confirmed that M. hyopneumoniae was able to adhere to ALI-PBECs and disrupt mucociliary function. Importantly, M. hyopneumoniae could migrate to the basolateral chamber through the paracellular route but not the transcellular pathway, and this was achieved by reversibly disrupting tight junctions (TJs) and increasing the permeability and damaging the integrity of the epithelial barrier. We examined the migration ability of M. hyopneumoniae using an ALI-PBECs model for the first time. The disruption of the epithelial barrier allowed M. hyopneumoniae to migrate to the basolateral chamber through the paracellular route, which may be related to immune evasion, extrapulmonary dissemination, and persistent infection of M. hyopneumoniae.

Survival of Mice with Gastrointestinal Acute Radiation Syndrome through Control of Bacterial Translocation.

Macrophages (Mϕ) with the M2b phenotype (Pheno2b-Mϕ) in bacterial translocation sites have been described as cells responsible for the increased susceptibility of mice with gastrointestinal acute radiation syndrome to sepsis caused by gut bacteria. In this study, we tried to reduce the mortality of mice exposed to 7-10 Gy of gamma rays by controlling Pheno2b-Mϕ polarization in bacterial translocation sites. MicroRNA-222 was induced in association with gamma irradiation. Pheno2b-Mϕ polarization was promoted and maintained in gamma-irradiated mice through the reduction of a long noncoding RNA growth arrest-specific transcript 5 (a CCL1 gene silencer) influenced by this microRNA. Therefore, the host resistance of 7-9-Gy gamma-irradiated mice to sepsis caused by bacterial translocation was improved after treatment with CCL1 antisense oligodeoxynucleotide. However, the mortality of 10-Gy gamma-irradiated mice was not alleviated by this treatment. The crypts and villi in the ileum of 10-Gy gamma-irradiated mice were severely damaged, but these were markedly improved after transplantation of intestinal lineage cells differentiated from murine embryonic stem cells. All 10-Gy gamma-irradiated mice given both of the oligodeoxynucleotide and intestinal lineage cells survived, whereas all of the same mice given either of them died. These results indicate that high mortality rates of mice irradiated with 7-10 Gy of gamma rays are reducible by depleting CCL1 in combination with the intestinal lineage cell transplantation. These findings support the novel therapeutic possibility of victims who have gastrointestinal acute radiation syndrome for the reduction of their high mortality rates.

Intestinal injury and gut permeability in sickle cell disease.

BACKGROUND: Due to recurrent hypoxia-reperfusion injury induced by vaso-occlusive crises (VOC), patients with sickle cell disease (SCD) may have intestinal injury and increased permeability. These may explain the qualitative and quantitative neutrophil abnormalities observed in these patients. METHODS: Serum intestinal fatty-acid binding protein (iFABP), lipopolysaccharides (LPS), and CD62L were measured by ELISA. Multicolor flow cytometry was used to measure circulating aged neutrophils. RESULTS: Compared to controls, SCD individuals had higher iFABP (median: 1.38 ng/ml vs 0.81 ng/ml; p = 0.04) and LPS (median: 2.15 µg/ml vs 0.69 µg/ml; p = 0.03), indicating intestinal injury and increased intestinal bacterial translocation into the systemic circulation. They also had higher soluble CD62L (median: 1.38 µg/ml vs 1.11 µg/ml; p = 0.04). Among SCD individuals, soluble CD62L correlated positively with circulating aged neutrophils (R = 0.7, p = 0.03) and LPS (R = 0.66, p = 0.027). Surprisingly, serum iFABP in SCD correlated negatively with both LPS (R = - 0.7, p = 0.02) and soluble CD62L (R = - 0.56, p = 0.08). CONCLUSIONS: Since LPS translocation across the intestinal barrier may be due to increases in the intestinal bacterial density, gut permeability, or both, the negative correlations between iFABP and LPS, and CD62L raise the possibility that any damage-associated molecular patterns induced by intestinal injury may modulate the degree of bacterial translocation. Our results provide the first evidence of the presence of intestinal injury and increased gut permeability in SCD.

Upregulation of the nitrosylome in bipolar disorder type 1 (BP1) and major depression, but not BP2: Increased IgM antibodies to nitrosylated conjugates are associated with indicants of leaky gut.

OBJECTIVE: Major depression (MDD) and a lifetime history of MDD are characterized by increased nitrosylation, while bipolar disorder type 1 (BP1), but not BP2, is accompanied by highly increased levels of oxidative stress and nitric oxide (NO) production. Nevertheless, it is unknown whether nitrosylation is involved in BP and whether there are differences in nitrosylation between BP1 and BP2. METHODS: Serum IgM antibodies directed against nitroso (NO)-adducts were examined in MDD, BP1, BP2 and healthy controls, namely IgM responses to NO-cysteine, NO-tryptophan (NOW), NO-arginine and NO-albumin (SBA) in association with IgA/IgM responses to LPS of Gram-negative bacteria, IgG responses to oxidized low-density lipoprotein (ox-LDL) and serum peroxides. RESULTS: Serum IgM levels against NO adducts were significantly higher in BP1 and MDD as compared with healthy controls, whereas BP2 patients occupied an intermediate position. IgM responses to NO-albumin were significantly higher in BP1 and MDD than in BP2 patients. There were highly significant associations between the IgM responses to NO-adducts and IgG responses to ox-LDL and IgA/IgM responses to Gram-negative bacteria. CONCLUSIONS: BP1 and MDD are characterized by an upregulation of the nitrosylome (the proteome of nitrosylated proteins) and increased IgM responses to nitrosylated conjugates. Increased nitrosylation may be driven by increased bacterial translocation and is associated with lipid peroxidation processes. Innate-like (B1 and marginal zone) B cells and increased nitrosylation may play a key role in the major affective disorders through activation of immune-inflammatory and oxidative pathways, cardiovascular comorbidity and impairments in antioxidant defenses, neuro-glial interactions, synaptic plasticity, neuroprotection, neurogenesis.

Bacterial Translocation Ratchets: Shared Physical Principles with Different Molecular Implementations: How bacterial secretion systems bias Brownian motion for efficient translocation of macromolecules.

Secretion systems enable bacteria to import and secrete large macromolecules including DNA and proteins. While most components of these systems have been identified, the molecular mechanisms of macromolecular transport remain poorly understood. Recent findings suggest that various bacterial secretion systems make use of the translocation ratchet mechanism for transporting polymers across the cell envelope. Translocation ratchets are powered by chemical potential differences generated by concentration gradients of ions or molecules that are specific to the respective secretion systems. Bacteria employ these potential differences for biasing Brownian motion of the macromolecules within the conduits of the secretion systems. Candidates for this mechanism include DNA import by the type II secretion/type IV pilus system, DNA export by the type IV secretion system, and protein export by the type I secretion system. Here, we propose that these three secretion systems employ different molecular implementations of the translocation ratchet mechanism.

Bacterial Dissemination to the Brain in Sepsis.

RATIONALE: Sepsis causes brain dysfunction and neuroinflammation. It is unknown whether neuroinflammation in sepsis is initiated by dissemination of bacteria to the brain and sustained by persistent infection, or whether neuroinflammation is a sterile process resulting solely from circulating inflammatory mediators. OBJECTIVES: To determine if gut bacteria translocate to the brain during sepsis, and are associated with neuroinflammation. METHODS: Murine sepsis was induced using cecal ligation and puncture, and sepsis survivor mice were compared with sham and unoperated control animals. Brain tissue of patients who died of sepsis was compared with patients who died of noninfectious causes. Bacterial taxa were characterized by 16S ribosomal RNA gene sequencing in both murine and human brain specimens; compared among sepsis and nonsepsis groups; and correlated with levels of S100A8, a marker of neuroinflammation using permutational multivariate ANOVA. MEASUREMENTS AND MAIN RESULTS: Viable gut-associated bacteria were enriched in the brains of mice 5 days after surviving abdominal sepsis (P < 0.01), and undetectable by 14 days. The community structure of brain-associated bacteria correlated with severity of neuroinflammation (P < 0.001). Furthermore, bacterial taxa detected in brains of humans who die of sepsis were distinct from those who died of noninfectious causes (P < 0.001) and correlated with S100A8/A9 expression (P < 0.05). CONCLUSIONS: Although bacterial translocation is associated with acute neuroinflammation in murine sepsis, bacterial translocation did not result in chronic cerebral infection. Postmortem analysis of patients who die of sepsis suggests a role for bacteria in acute brain dysfunction in sepsis. Further work is needed to determine if modifying gut-associated bacterial communities modulates brain dysfunction after sepsis.

The menstrual cycle may not be limited to the endometrium but also may impact gut permeability.

OBJECTIVE: To examine associations between IgA responses to Gram-negative gut commensal bacteria and peri-menstrual symptoms and sex hormone levels during the menstrual cycle in women with and without premenstrual symptoms. METHODS: Forty women aged 18-45 years completed the Daily Record of Severity of Problems (DRSP) during all 28 consecutive days of the menstrual cycle. We assayed, in plasma, IgA responses to six Gram-negative bacteria, that is, Hafnei alvei, Pseudomonas aeruginosa, Morganella morganii, Klebsiella pneumoniae, Pseudomonas putida and Citobacter koseri, progesterone and oestradiol at days 7, 14, 21 and 28 of the menstrual cycle. RESULTS: Significant changes in Δ (actual - 1 week earlier) IgA to lipopolysaccharides (LPS) of the six Gram-negative bacteria during the menstrual cycle were observed with peak IgA levels at T4 (day 28) and lows at T1 or T2 (day 7 or 14). The ΔIgA changes in H. alvei, M. Morganii, P. putida during the menstrual cycle were significantly and positively associated with changes in the total DRSP score, and severity of physio-somatic, anxiety and breast-craving, but not depressive, symptoms. The changes in IgA responses to LPS were largely predicted by changes in progesterone and steady-state levels of progesterone averaged over the luteal phase. DISCUSSION: Menstrual cycle-associated changes in IgA directed against LPS and by inference bacterial translocation may be driven by the effects of progesterone on transcellular, paracellular and vascular pathways (leaky gut) thereby contributing to the severity of physio-somatic and anxiety symptoms as well as fatigue, breast swelling and food cravings.

Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut.

Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of Lactobacillus species probiotics is still controversial. We evaluated the therapeutic effects of Lactobacillus rhamnosus L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either Klebsiella pneumoniae or Salmonella enterica serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone. Salmonella bacteremia was found in only 16 to 29% and 0% of mice with Salmonella and Klebsiella administrations, respectively. Klebsiella bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with Klebsiella and Salmonella administrations, respectively. Lactobacillus rhamnosus L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal Salmonella bacteria with Lactobacillus treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from Lactobacillus rhamnosus L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells in vitro In conclusion, Lactobacillus rhamnosus L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.

Beneficial Effect of Alcohol Withdrawal on Gut Permeability and Microbial Translocation in Patients with Alcohol Use Disorder.

BACKGROUND: The human intestinal microbiota exerts beneficial or harmful effects in several disorders. Many factors, including alcohol consumption, may influence its composition and trigger bacterial translocation. Excessive alcohol consumption increases gut permeability and translocation of endotoxin into peripheral circulation. Although plasma endotoxin concentrations have been measured often, quantitative changes following alcohol withdrawal have never been described in subjects with alcohol use disorder (AUD). The aim of this study was to measure microbial translocation (MT) and gut permeability markers in patients with AUD, to compare these markers to healthy controls (HC) and to monitor markers during the first 6 weeks of abstinence. METHODS: Sixty-five patients with AUD and hospitalized for alcohol withdrawal were included. Epidemiological, clinical, biological, and addictological data were gathered. Blood samples were collected at baseline, then 3 and 6 weeks after alcohol withdrawal. A hundred healthy volunteers were used as controls. Three markers of MT were monitored in plasma samples: sCD14 and lipopolysaccharide-binding protein (LBP) were quantified using ELISA, and 16S rDNA was quantified using real-time polymerase chain reaction. Zonulin and intestinal fatty acid binding protein (I-FABP) blood levels were also monitored as indirect markers of gut permeability, using ELISA. RESULTS: At baseline, LBP, 16S rDNA, sCD14 and I-FABP markers were significantly higher in patients with AUD than in HC. Six weeks after alcohol withdrawal plasma levels of sCD14 and LBP decreased significantly. Cannabis consumption and body mass index (BMI) before alcohol withdrawal influenced baseline MT levels and the decrease in MT markers after 6 weeks. Finally, markers of MT and gut permeability did not correlate with each other before and after alcohol withdrawal. CONCLUSIONS: Before alcohol withdrawal, MT markers were higher in patients with AUD than in HC. After 6 weeks of abstinence, an improvement in MT markers was observed. Our data suggest that there is a link between MT, its improvement, BMI, and cannabis consumption.

Impact of circulating bacterial DNA in long-term glucose homeostasis in non-diabetic patients with HIV infection: cohort study.

In HIV-infected patients, the damage in the gut mucosal immune system is not completely restored after antiretroviral therapy (ART). It results in microbial translocation, which could influence the immune and inflammatory response. We aimed at investigating the long-term impact of bacterial-DNA translocation (bactDNA) on glucose homeostasis in an HIV population. This was a cohort study in HIV-infected patients whereby inclusion criteria were: patients with age >18 years, ART-naïve or on effective ART (<50 HIV-1 RNA copies/mL) and without diabetes or chronic hepatitis C. Primary outcome was the change in HbA1c (%). Explanatory variables at baseline were: bactDNA (qualitatively detected in blood samples by PCR [broad-range PCR] and gene 16SrRNA - prokaryote), ART exposure, HOMA-R and a dynamic test HOMA-CIGMA [continuous infusion of glucose with model assessment], hepatic steatosis (hepatic triglyceride content - 1H-MRS), visceral fat / subcutaneous ratio and inflammatory markers. Fifty-four men (age 43.2 ± 8.3 years, BMI 24.9 ± 3 kg/m2, mean duration of HIV infection of 8.1 ± 5.3 years) were included. Baseline HbA1c was 4.4 ± 0.4% and baseline presence of BactDNA in six patients. After 8.5 ± 0.5 years of follow-up, change in HbA1c was 1.5 ± 0.47% in patients with BactDNA vs 0.87 ± 0.3% in the rest of the sample p < 0.001. The change in Hba1c was also influenced by protease inhibitors exposure, but not by baseline indices of insulin resistance, body composition, hepatic steatosis, inflammatory markers or anthropometric changes. In non-diabetic patients with HIV infection, baseline bacterial translocation and PI exposure time were the only factors associated with long-term impaired glucose homeostasis.

First evidence of bacterial translocation from the intestinal tract as a route of Helicobacter cinaedi bacteremia.

BACKGROUND: The route of Helicobacter cinaedi bacteremia has not yet been clarified. Although bacterial translocation from the intestinal tract into the circulation has been suggested, it has not been demonstrated thus far. The objective of this study was to investigate the port of entry of this bacterium. MATERIAL AND METHODS: We conducted a retrospective study on patients with H. cinaedi bacteremia between March 2009 and May 2013. Records of patients in whom H. cinaedi was detected in both blood and stool cultures were extracted. H. cinaedi was identified using gyrB-targeted PCR. Pulse-field gel electrophoresis was used to investigate the consistency of the genotypes. RESULTS: Seventy-one patients were diagnosed with H. cinaedi bacteremia during the study period. H. cinaedi was detected in both blood and stool samples of 21 patients. Pulse-field gel electrophoresis was used to investigate the consistency of the genotypes in 18 evaluable strains (from 9 patients). The pulse-field gel electrophoresis patterns of the stool- and blood-derived strains of H. cinaedi were consistent among all 9 patients. Most of the 9 patients analyzed were immunocompromised and being treated with anticancer drugs or steroids, which suggests reduced intestinal immunity. CONCLUSIONS: This is the first study to demonstrate that bacterial translocation from the intestinal tract could represent one route of H. cinaedi bacteremia.

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.

Autophagy Strengthens Intestinal Mucosal Barrier by Attenuating Oxidative Stress in Severe Acute Pancreatitis.

BACKGROUND: Intestinal mucosal barrier dysfunction can be caused by severe acute pancreatitis (SAP). It is normally associated with changes to mucosal autophagy and oxidative stress. OBJECTIVE: The aim of this study was to investigate the correlation between autophagy and oxidative stress on the intestinal mucosal barrier of SAP rat model. METHODS: SAP was induced by retrograde injection of sodium taurocholate (5%) into the biliopancreatic duct. Bacterial translocation (BT) was detected by 16S rDNA sequencing analysis. Morphological alterations in the pancreas and gut were determined by hematoxylin-eosin staining. Oxidative stress status was determined by measuring the level of intestinal malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx). Western blot, RT-PCR, and immunofluorescent staining were preformed to analyze the expression of tight junction and autophagy proteins. RESULTS: According to the sequencing analysis, rats in SAP group were divided into BT (+) group (n = 9) and BT (-) group (n = 8). Pancreatic and intestinal injuries in SAP group were significantly higher than sham operation group. The content of MDA was clearly elevated, and SOD as well as GPx activities were decreased in BT (+) group as compared with BT (-) group. The expression of LC3II and Beclin1 in BT (-) group was higher than that observed in BT (+). In contrast, BT (+) group had a higher level of claudin-2 and a lower level of zonula occluden-1, occludin, and claudin-1. CONCLUSION: These results suggest that activated autophagy may attenuate intestinal mucosal barrier dysfunction by preventing and reducing the oxidative stress in SAP.

Effects of bacterial translocation on hemodynamic and coagulation parameters during living-donor liver transplant.

BACKGROUND: Bacterial translocation (BT) has been proposed as a trigger for stimulation of the immune system with consequent hemodynamic alteration in patients with liver cirrhosis. However, no information is available regarding its hemodynamic and coagulation consequences during liver transplantation. METHODS: We screened 30 consecutive adult patients undergoing living-donor liver transplant for the presence of BT. Bacterial DNA, Anti factor Xa (aFXa), thromboelastometry, tumor necrosis factor-α TNF-α, and interleukin-17 (IL-17) values were measured in sera before induction of anesthesia. Systemic hemodynamic data were recorded throughout the procedures. RESULTS: Bacterial DNA was detected in 10 patients (33%) (bactDNA(+)). Demographic, clinical, and hemodynamic data were similar in patients with presence or absence of bacterial DNA. BactDNA(+) patients showed significantly higher circulating values of TNF-α and IL-17, and had significantly higher clotting times and clot formation times as well as significantly lower alpha angle and maximal clot firmness than bactDNA(-) patients, P < 0.05. We found no statistically significant difference in aFXa between the groups, P = 0.4. Additionally, 4 patients in each group needed vasopressor agents, P = 0.2. And, the amount of transfused blood and blood products used were similar between both groups. CONCLUSION: Bacterial translocation was found in one-third of patients at the time of transplantation and was largely associated with increased markers of inflammation along with decreased activity of coagulation factors. TRIAL REGISTRATION: Trial Registration Number: NCT03230214 . (Retrospective registered). Initial registration date was 20/7/2017.

Rapid baso-apical translocation of Mycobacterium avium ssp. paratuberculosis in mammary epithelial cells in the presence of Escherichia coli.

Infection of mammary gland cells with bacterial pathogens begins with adhesion, invasion, and persistence within the cells or systemic distribution. Some bacteria, such as Escherichia coli, are known to causes bovine mastitis, resulting in acute proinflammatory responses in the mammary tissue. Mycobacterium avium ssp. paratuberculosis (MAP), the etiological agent of paratuberculosis, is able to spread to distant organs after crossing intestinal cells, reaching the mammary gland and potentially being released in milk, infecting calves during suckling. Its exit from systemic sites may be influenced by preexisting inflammation such as that caused by E. coli mastitis. Interactions between E. coli and MAP in mammary epithelial cells have not yet been described. In this study, we posited that E. coli-infected bovine mammary epithelial cells would facilitate baso-apical translocation of MAP in an ex vivo model. We showed that the presence of E. coli in a bovine mammary epithelial cell line (MAC-T) increased baso-apical translocation of MAP to the apical side of the cells. Levels were significantly higher 30 min post-infection and decreased at 120 min post-infection. Cells previously infected with E. coli and MAP or with E. coli alone showed a significant increase in IL1B mRNA expression at 120 min. We detected no significant expression of p38 mitogen-activated protein kinase (mapkp38) or IL10, regardless of treatment. Thereby, the presence of E. coli in MAC-T cells alters the translocation of MAP through epithelial cells, enabling its rapid translocation to the cellular surface. Expression of IL1B was shown to influence the apical-basal translocation of MAP at 120 min. Findings from the current study suggest that MAP translocation into milk is likely enhanced by inflammatory states such as those induced during E. coli mastitis. This is the first report demonstrating the effect of E. coli under MAP coinfection in bovine mammary epithelial cells under experimental conditions.

More of the Gut in the Lung: How Two Microbiomes Meet in ARDS.

In critically ill patients, lung and gut microbiomes undergo profound changes. Lung microbiome might become enriched with gut-associated microbes as recently demonstrated in sepsis and acute respiratory distress syndrome (ARDS). It has been proposed that in these conditions, bacteria from the gut might enter the lungs via translocation, a process facilitated by increased gut and alveolo-capillary permeability. In patients requiring mechanical ventilation after severe trauma, lung microbiome enrichment with gut-associated microbes was found to correlate with the development of ARDS. The lungs in ARDS are increasingly susceptible to opportunistic infections which can further perpetuate alveolar inflammation and injury. Undoubtedly, more research on the gut-lung crosstalk in critically ill patients is needed to identify causal relationships between the altered microbiome, infections, inflammation, and acute lung injury. With further insights, this area of investigation could lead to the development of novel, microbiome-targeted, and immunomodulation strategies with the potential to improve outcomes of critically ill patients with sepsis, trauma, and ARDS.

Microbial Translocation Associated with an Acute-Phase Response and Elevations in MMP-1, HO-1, and Proinflammatory Cytokines in Strongyloides stercoralis Infection.

Microbial translocation, characterized by elevated levels of lipopolysaccharide (LPS) and related markers, is a common occurrence in HIV and some parasitic infections. This is usually associated with extensive inflammation and immune activation. To examine the occurrence of microbial translocation and the associated inflammatory response in asymptomatic Strongyloides stercoralis infection, we measured the plasma levels of LPS and other microbial translocation markers, acute-phase proteins, inflammatory markers, and proinflammatory cytokines in individuals with (infected [INF]) or without (uninfected [UN]) S. stercoralis infections. Finally, we also measured the levels of all of these markers in INF individuals following treatment of S. stercoralis infection. We show that INF individuals exhibit significantly higher plasma levels of microbial translocation markers (LPS, soluble CD14 [sCD14], intestinal fatty acid-binding protein [iFABP], and endotoxin core IgG antibody [EndoCAb]), acute-phase proteins (α-2 macroglobulin [α-2M], C-reactive protein [CRP], haptoglobin, and serum amyloid protein A [SAA]), inflammatory markers (matrix metalloproteinase 1 [MMP-1] and heme oxygenase 1 [HO-1]), and proinflammatory cytokines (interleukin-6 [IL-6], IL-8, monocyte chemoattractant protein 1 [MCP-1], and IL-1ß) than do UN individuals. INF individuals exhibit significantly decreased levels of tissue inhibitor of metalloproteinases 4 (TIMP-4). Following treatment of S. stercoralis infection, the elevated levels of microbial translocation markers, acute-phase proteins, and inflammatory markers were all diminished. Our data thus show that S. stercoralis infection is characterized by microbial translocation and accompanying increases in levels of acute-phase proteins and markers of inflammation and provide data to suggest that microbial translocation is a feature of asymptomatic S. stercoralis infection and is associated with an inflammatory response.

The gut microbiome and microbial translocation in multiple sclerosis.

Individuals with multiple sclerosis (MS) have a distinct intestinal microbial community (microbiota) and increased low-grade translocation of bacteria from the intestines into the circulation. The observed change of intestinal bacteria in MS patients regulate immune functions involved in MS pathogenesis. These functions include: systemic and central nervous system (CNS) immunity (including peripheral regulatory T cell function), the blood-brain barrier (BBB) permeability and CNS-resident cell activity. This review discusses the MS intestinal microbiota implication on MS systemic- and CNS-immunopathology. We introduce the possible contributions of MS low-grade microbial translocation (LG-MT) to the development of MS, and end on a discussion on microbiota therapies for MS patients.