Impaired AhR ligand production by the gut microbiota decreases AhR pathway activation, promoting ... more Impaired AhR ligand production by the gut microbiota decreases AhR pathway activation, promoting inflammation in celiac disease.
real-time reverse transcription-polymerase chain reaction . To clarify the role of HMGB1 in heali... more real-time reverse transcription-polymerase chain reaction . To clarify the role of HMGB1 in healing of gastric ulcer, the mice were intraperitoneally administered mouse recombinant HMGB1 (rHMGB1), anti-HMGB1 neutralizing antibodies or nonspecific chicken IgY after the induction of ulcer.Results: At day 4 after ulcer induction, mean ulcer sizes did not differ among the 4 groups. Endothelial cells and inflammatory cells such as macrophages in the ulcerous region showed immunoreactivity for TLR2 and TLR4 and RAGE proteins. By day 9, the ulcer size in RAGE KO mice and TLR4 KO mice was 40% smaller than that in wild-type mice, while there was no difference in ulcer sizes between wild-type mice and TLR2 KO mice. Deficiency of RAGE and TLR4 markedly inhibited the increase in expression of TNF-αmRNA in ulcerous tissue. Administration of rHMGB1 delayed the healing of gastric ulcer (ulcer index: 1.39 ± 0.30 mm2 in the vehicle-treated mice and 4.52 ± 0.35 mm2 in rHMGB1-treated mice), accompanied by increase in expression of TNF-α mRNA and MPO activities in ulcerous tissue, while administration of anti-HMGB1 antibody enhanced ulcer healing by day 9 (ulcer index: 2.90 ± 0.86 mm2 in non-specific IgY-treated mice, 1.46 ± 0.80 mm2 in neutralizing antibody for HMGB1-treated mice). Conclusion: These results suggest that HMGB1 is a critical factor that delays healing of gastric ulcer not via TLR2 but via TLR4 and RAGE.
Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the di... more Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the diagnosis of celiac disease. It is well known that immunoglobulin A tissue transglutaminase levels correlate with the degree of intestinal damage, and that values can fluctuate in patients over time. Serological testing can be used to identify symptomatic individuals that need a confirmatory biopsy, to screen at-risk populations or to monitor diet compliance in patients previously diagnosed with celiac disease. Thus, interpretation of serological testing requires consideration of the full clinical scenario. Antigliadin tests are no longer recommended for the diagnosis of classical celiac disease. However, our understanding of the pathogenesis and spectrum of gluten sensitivity has improved, and gluten-sensitive irritable bowel syndrome patients are increasingly being recognized. Studies are needed to determine the clinical utility of antigliadin serology in the diagnosis of gluten sensitiv...
The comparative effects of omeprazole and lansoprazole on gastric acidity in Helicobacter pylori-... more The comparative effects of omeprazole and lansoprazole on gastric acidity in Helicobacter pylori-positive subjects and the clearance of H. pylori are unknown. Eighteen asymptomatic H. pylori-positive subjects were studied. Each volunteer received 7 days of omeprazole, lansoprazole, or placebo in a randomized, double-blind, crossover study, with a washout period of 4-6 weeks between treatments. At the end of each treatment period 24-h dual-point intragastric pH-metry was performed, and H. pylori clearance was assessed. Both omeprazole (corpus/antrum pH: 5.5/5.5) and lansoprazole (5.4/5.4) increased intragastric pH compared with placebo (1.5/1.3). Over the 24-h recording there was no difference between the two treatments with regard to control of intragastric pH or clearance of H. pylori. Omeprazole, 20 mg once daily, and lansoprazole, 30 mg once daily, are comparably effective antisecretory agents in H. pylori-positive subjects. Both agents provide only transient clearance of H. pylori in a few subjects.
Background-The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hipp... more Background-The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hippocampal brain derived neurotrophic factor (BDNF) in mice with infectious colitis. Using a model of chemical colitis we test whether the anxiolytic effect of B. longum involves vagal integrity, and changes in neural cell function. Methods-Mice received dextran sodium sulfate (DSS, 3%) in drinking water during three 1week cycles. Bifidobacterium longum or placebo were gavaged daily during the last cycle. Some mice underwent subdiaphragmatic vagotomy. Behavior was assessed by step-down test, inflammation by myeloperoxidase (MPO) activity and histology. BDNF mRNA was measured in neuroblastoma SH-SY5Y cells after incubation with sera from B. longum-or placebo-treated mice. The effect of B. longum on myenteric neuron excitability was measured using intracellular microelectrodes. Key Results-Chronic colitis was associated with anxiety-like behavior, which was absent in previously vagotomized mice. B. longum normalized behavior but had no effect on MPOactivity or histological scores.
Background.~ Helicobacter pylori (H. pylori) produces large amounts of ammonia. Based on higher r... more Background.~ Helicobacter pylori (H. pylori) produces large amounts of ammonia. Based on higher readings obtained with an ammonia‐sensitive electrode when compared to a specific enzymatic assay, it has been claimed that H. pylori also produces potentially toxic volatile amines.Method.We measured ammonia concentrations (NH3) in gastric aspirates from 11 H. pylori positive subjects (22–40 y, 6~ m), using an ammonia electrode sensitive to ammonia and amines, and an enzymatic assay specific for ammonia. Continuous aspiration was performed overnight and 220 aspirates were analyzed before and 6~weeks after cure of H. pylori. Gastric samples were diluted 1:3 (before cure) and 1:1 (after cure) according to dilution curves constructed prior to the assays.Results.Median (95% CI) NH3 detected by the elec‐trode/enzymatic assay were 4.34~m m[4.12–4.61]/4.50~m m [4.28–4.68] (p~>~.05) before cure and 0.54~m m[0.42–0.60]/0.73~m m[0.71–0.81] after cure (p~>~.05). Intra‐class correlation coeffi...
It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacte... more It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacter pylori positive subjects than in H pylori negative subjects. This study aimed to investigate the effect of curing H pyloni on the intragastric pH in both the presence and absence of omeprazole therapy. Twenty four hour intragastric pH recordings were performed before and after a one week course of omeprazole (20 mg once daily) in 18 H pyloni positive subjects and were repeated after the infection had been cured. In the absence of omeprazole, the total 24 hour pH values before cure did not differ from those afterwards. During omeprazole treatment the 24 hour pH values were much higher before (median (95% CI) 5.4: 4.3, 6.0), than after cure of infection (3.6: 2.1, 4.4; p<0.001). The omeprazole induced fall in H' activity before cure of H pylorn did not, however, differ from that afterwards. It is concluded that the apparently greater antisecretory effect of omeprazole during H pylorn infection may be a result of the production of acid neutralising compounds by the H pylorn. Although a direct interaction between H pylori and omeprazole cannot be excluded, it seems unlikely.
Previous studies have suggested that profound inhibition of gastric acid secretion may increase e... more Previous studies have suggested that profound inhibition of gastric acid secretion may increase exposure to potentially carcinogenic N-nitroso compounds. The aim of this study was to find out if the proton pump inhibitor omeprazole (20 mg daily) is associated with increased concentrations of potentially carcinogenic N-nitroso compounds in gastric juice. The volume of gastric contents, number of bacteria, and concentrations of nitrates, nitrites, and N-nitroso compounds was determined in gastric aspirates obtained after an overnight fast in 14 healthy volunteers (7M:7F) after one week of treatment with placebo, and one and two weeks' treatment with omeprazole. Median bacterial concentrations were 1*Ox 104 (range 5 0 x 103-5-0 x 106) colony forming units (CFU)/ml after one weeks' treatment with placebo and increased significantly to 4-OX105 (0-3.3x 107) CFU/ml after two weeks' treatment with omeprazole (p<0.05). A similar increase was seen in the concentration of nitrate reducing bacteria. There was no difference in the volume of gastric aspirates after treatment with omeprazole when compared with placebo (65 (29-155) ml v 42 (19-194) ml). The concentration of N-nitroso compounds was 0-13 (0-1-0) ptmol/l after two weeks of omeprazole, which was not significantly different from that seen with placebo (0-15 (0-0.61) tmol/l). There was also no increase in the concentrations of nitrates or nitrites. It is concluded that omeprazole (20 mg once daily) for two weeks in healthy volunteers is associated with gastric bacterial proliferation but does not increase concentrations of N-nitroso compounds.
ABSTRACT It has been shown that omeprazole treatment produces higher intragastric pH values in He... more ABSTRACT It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacter pylori positive subjects than in H pylori negative subjects. This study aimed to investigate the effect of curing H pylori on the intragastric pH in both the presence and absence of omeprazole therapy. Twenty four hour intragastric pH recordings were performed before and after a one week course of omeprazole (20 mg once daily) in 18 H pylori positive subjects and were repeated after the infection had been cured. In the absence of omeprazole, the total 24 hour pH values before cure did not differ from those afterwards. During omeprazole treatment the 24 hour pH values were much higher before (median (95% CI) 5.4: 4.3, 6.0), than after cure of infection (3.6: 2.1, 4.4; p &lt; 0.001). The omeprazole induced fall in H+ activity before cure of H pylori did not, however, differ from that afterwards. It is concluded that the apparently greater antisecretory effect of omeprazole during H pylori infection may be a result of the production of acid neutralising compounds by the H pylori. Although a direct interaction between H pylori and omeprazole cannot be excluded, it seems unlikely.
relative to the control cells. IL-8 was up-regulated by 19.4 ± 4.2 fold (P < 0.01), TNF was up-re... more relative to the control cells. IL-8 was up-regulated by 19.4 ± 4.2 fold (P < 0.01), TNF was up-regulated 5.6 ± 0.6 fold (P < 0.01), when the C2BBe1 cells treated with Stav relative to the controls. In the SW-620 cell line IFN-α and IFN-β were upregulated (3.3 ± 0.7 fold (P<0.05) and 3.2 ± 0.8 fold (P<0.05) respectively) when treated with Carlow VLP's. When SW-620 were treated with Stav VLP's IL-8 and IL-12 were upregulated (1.8 ± 0.08 fold (P< 0.05) and 3.5 ± 0.46 fold (P<0.01). Furthermore TLR-2, is up-regulated (2.4 ± 0.4 fold (P<0.05)) in SW-620 when treated with Carlow VLP's. Summary: These results show the utility of FUT2 expressing cell lines in the study of NoV infection and suggest that differential immune activation patterns are associated with susceptability to this virus. Further studies are warranted to investigate the involvement of TLR's in this phenomenon.
Background: Transglutaminase 2 (TG2) is a multifunctional protein with transamidase as well as si... more Background: Transglutaminase 2 (TG2) is a multifunctional protein with transamidase as well as signaling activities. Its aberrant catalytic activity has been implicated in the pathogenesis of celiac sprue. However, the physiological role of TG2 and the mechanisms for its In Vivo activation in the small intestine are largely unknown. Aims: To study the TG2 catalytic activity under basal conditions and to identify signals that induce TG2 activity. Methods: We used selective TG2 inhibitors and tagged nucleophilic substrates to monitor the In Vivo TG2 activity during experimental conditions such as fibroblast scratch assay or methotrexate and polyinosinic-polycytidylic acid (poly(I:C)) administration in mice. Results: The majority of TG2 is inactive under normal physiological conditions in cell culture and In Vivo. However, abundant TG2 activity can be detected around the wound in a standard cultured fibroblast scratch assay. To induce tissue injury model in mice, we used methotrexate and poly(I:C), since they trigger small intestinal injury characterized by villous atrophy similar to celiac sprue. The acute poly(I:C) injury model, but not the methotrexate model, resulted in activation of the small intestinal TG2 and in cellular protein crosslinking. Conclusions: Extracellular TG2 is predominantly inactive under physiological conditions. It is activated upon tissue injury or in response to innate immune signals such us poly (I:C). Our results illustrate a new tool to investigate the biology of TG2 in the small intestine. They also provide convenient assays for evaluating small molecule inhibitors of extracellular TG2 activity In Vitro and In Vivo.
See Covering the Cover synopsis on page 409. BACKGROUND & AIMS: Alterations in the microbial comp... more See Covering the Cover synopsis on page 409. BACKGROUND & AIMS: Alterations in the microbial composition of the gastrointestinal tract (dysbiosis) are believed to contribute to inflammatory and functional bowel disorders and psychiatric comorbidities. We examined whether the intestinal microbiota affects behavior and brain biochemistry in mice. METHODS: Specific pathogen-free (SPF) BALB/c mice, with or without subdiaphragmatic vagotomy or chemical sympathectomy, or germ-free BALB/c mice received a mixture of nonabsorbable antimicrobials (neomycin, bacitracin, and pimaricin) in their drinking water for 7 days. Germ-free BALB/c and NIH Swiss mice were colonized with microbiota from SPF NIH Swiss or BALB/c mice. Behavior was evaluated using step-down and light preference tests. Gastrointestinal microbiota were assessed using denaturing gradient gel electrophoresis and sequencing. Gut samples were analyzed by histologic, myeloperoxidase, and cytokine analyses; levels of serotonin, noradrenaline, dopamine, and brain-derived neurotropic factor (BDNF) were assessed by enzymelinked immunosorbent assay. RESULTS: Administration of oral antimicrobials to SPF mice transiently altered the composition of the microbiota and increased exploratory behavior and hippocampal expression of BDNF. These changes were independent of inflammatory activity, changes in levels of gastrointestinal neurotransmitters, and vagal or sympathetic integrity. Intraperitoneal administration of antimicrobials to SPF mice or oral administration to germ-free mice did not affect behavior. Colonization of germ-free BALB/c mice with microbiota from NIH Swiss mice increased exploratory behavior and hippocampal levels of BDNF, whereas colonization of germfree NIH Swiss mice with BALB/c microbiota reduced exploratory behavior. CONCLUSIONS: The intestinal microbiota influences brain chemistry and behavior independently of the autonomic nervous system, gastrointestinal-specific neurotransmitters, or inflammation. Intestinal dysbiosis might contribute to psychiatric disorders in patients with bowel disorders.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2008
Bacterial infection can trigger the development of functional GI disease. Here, we investigate th... more Bacterial infection can trigger the development of functional GI disease. Here, we investigate the role of the gut-brain axis in gastric dysfunction during and after chronic H. pylori infection. Control and chronically H. pylori-infected Balb/c mice were studied before and 2 mo after bacterial eradication. Gastric motility and emptying were investigated using videofluoroscopy image analysis. Gastric mechanical viscerosensitivity was assessed by cardioautonomic responses to distension. Feeding patterns were recorded by a computer-assisted system. Plasma leptin, ghrelin, and CCK levels were measured using ELISA. IL-1β, TNF-α, proopiomelanocortin (POMC), and neuropeptide Y mRNAs were assessed by in situ hybridizations on frozen brain sections. Gastric inflammation was assessed by histology and immunohistochemistry. As shown previously, H. pylori-infected mice ate more frequently than controls but consumed less food per bout, maintaining normal body weight. Abnormal feeding behavior was...
American Journal of Physiology-Gastrointestinal and Liver Physiology, 2008
The role of chronic infections, such as Helicobacter pylori ( Hp), to produce sustained changes i... more The role of chronic infections, such as Helicobacter pylori ( Hp), to produce sustained changes in host physiology remains controversial. In this study, we investigate whether the antigenic or bacterial content of the gut, after Hp eradication, influences the changes in gut function induced by chronic Hp infection. Mice were infected with Hp for 4 mo and then treated with antibiotics or placebo for 2 wk. Gastric emptying was measured using videofluoroscopy, feeding behavior using a 24-h feeding system, and intestinal permeability using an isolated jejunal segment arterially perfused with an artificial oxygen carrier, hemoglobin vesicles. Immune responses were assessed by CD3+cell counts and anti- Hp antibodies using ELISA. To determine the role of luminal factors in host physiology posteradication, groups of mice received the probiotics containing Lactobacillus rhamnosus R0011 and L. helveticus R0052 or placebo for 2 wk or crude Hp antigen weekly for 2 mo. Chronic Hp infection was a...
Systemic administration of polyinosinic:polycytidylic acid (poly I:C), mimics virally-induced act... more Systemic administration of polyinosinic:polycytidylic acid (poly I:C), mimics virally-induced activation of TLR3 signalling causing acute small intestine damage, but whether and how mucosal administration of poly I:C causes enteropathy is less clear. Our aim was to investigate the inflammatory pathways elicited after intraluminal administration of poly I:C and determine acute and delayed consequences of this locally induced immune activation. Intraluminal poly I:C induced rapid mucosal immune activation in C57BL/6 mice involving IFNb and the CXCL10/CXCR3 axis, that may drive inflammation towards a Th1 profile. Intraluminal poly I:C also caused enteropathy and gut dysfunction in gliadin-sensitive NOD-DQ8 mice, and this was prolonged by concomitant oral administration of gliadin. Our results indicate that small intestine pathology can be induced in mice by intraluminal administration of poly I:C and that this is exacerbated by subsequent oral delivery of a relevant dietary antigen.
Impaired AhR ligand production by the gut microbiota decreases AhR pathway activation, promoting ... more Impaired AhR ligand production by the gut microbiota decreases AhR pathway activation, promoting inflammation in celiac disease.
real-time reverse transcription-polymerase chain reaction . To clarify the role of HMGB1 in heali... more real-time reverse transcription-polymerase chain reaction . To clarify the role of HMGB1 in healing of gastric ulcer, the mice were intraperitoneally administered mouse recombinant HMGB1 (rHMGB1), anti-HMGB1 neutralizing antibodies or nonspecific chicken IgY after the induction of ulcer.Results: At day 4 after ulcer induction, mean ulcer sizes did not differ among the 4 groups. Endothelial cells and inflammatory cells such as macrophages in the ulcerous region showed immunoreactivity for TLR2 and TLR4 and RAGE proteins. By day 9, the ulcer size in RAGE KO mice and TLR4 KO mice was 40% smaller than that in wild-type mice, while there was no difference in ulcer sizes between wild-type mice and TLR2 KO mice. Deficiency of RAGE and TLR4 markedly inhibited the increase in expression of TNF-αmRNA in ulcerous tissue. Administration of rHMGB1 delayed the healing of gastric ulcer (ulcer index: 1.39 ± 0.30 mm2 in the vehicle-treated mice and 4.52 ± 0.35 mm2 in rHMGB1-treated mice), accompanied by increase in expression of TNF-α mRNA and MPO activities in ulcerous tissue, while administration of anti-HMGB1 antibody enhanced ulcer healing by day 9 (ulcer index: 2.90 ± 0.86 mm2 in non-specific IgY-treated mice, 1.46 ± 0.80 mm2 in neutralizing antibody for HMGB1-treated mice). Conclusion: These results suggest that HMGB1 is a critical factor that delays healing of gastric ulcer not via TLR2 but via TLR4 and RAGE.
Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the di... more Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the diagnosis of celiac disease. It is well known that immunoglobulin A tissue transglutaminase levels correlate with the degree of intestinal damage, and that values can fluctuate in patients over time. Serological testing can be used to identify symptomatic individuals that need a confirmatory biopsy, to screen at-risk populations or to monitor diet compliance in patients previously diagnosed with celiac disease. Thus, interpretation of serological testing requires consideration of the full clinical scenario. Antigliadin tests are no longer recommended for the diagnosis of classical celiac disease. However, our understanding of the pathogenesis and spectrum of gluten sensitivity has improved, and gluten-sensitive irritable bowel syndrome patients are increasingly being recognized. Studies are needed to determine the clinical utility of antigliadin serology in the diagnosis of gluten sensitiv...
The comparative effects of omeprazole and lansoprazole on gastric acidity in Helicobacter pylori-... more The comparative effects of omeprazole and lansoprazole on gastric acidity in Helicobacter pylori-positive subjects and the clearance of H. pylori are unknown. Eighteen asymptomatic H. pylori-positive subjects were studied. Each volunteer received 7 days of omeprazole, lansoprazole, or placebo in a randomized, double-blind, crossover study, with a washout period of 4-6 weeks between treatments. At the end of each treatment period 24-h dual-point intragastric pH-metry was performed, and H. pylori clearance was assessed. Both omeprazole (corpus/antrum pH: 5.5/5.5) and lansoprazole (5.4/5.4) increased intragastric pH compared with placebo (1.5/1.3). Over the 24-h recording there was no difference between the two treatments with regard to control of intragastric pH or clearance of H. pylori. Omeprazole, 20 mg once daily, and lansoprazole, 30 mg once daily, are comparably effective antisecretory agents in H. pylori-positive subjects. Both agents provide only transient clearance of H. pylori in a few subjects.
Background-The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hipp... more Background-The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hippocampal brain derived neurotrophic factor (BDNF) in mice with infectious colitis. Using a model of chemical colitis we test whether the anxiolytic effect of B. longum involves vagal integrity, and changes in neural cell function. Methods-Mice received dextran sodium sulfate (DSS, 3%) in drinking water during three 1week cycles. Bifidobacterium longum or placebo were gavaged daily during the last cycle. Some mice underwent subdiaphragmatic vagotomy. Behavior was assessed by step-down test, inflammation by myeloperoxidase (MPO) activity and histology. BDNF mRNA was measured in neuroblastoma SH-SY5Y cells after incubation with sera from B. longum-or placebo-treated mice. The effect of B. longum on myenteric neuron excitability was measured using intracellular microelectrodes. Key Results-Chronic colitis was associated with anxiety-like behavior, which was absent in previously vagotomized mice. B. longum normalized behavior but had no effect on MPOactivity or histological scores.
Background.~ Helicobacter pylori (H. pylori) produces large amounts of ammonia. Based on higher r... more Background.~ Helicobacter pylori (H. pylori) produces large amounts of ammonia. Based on higher readings obtained with an ammonia‐sensitive electrode when compared to a specific enzymatic assay, it has been claimed that H. pylori also produces potentially toxic volatile amines.Method.We measured ammonia concentrations (NH3) in gastric aspirates from 11 H. pylori positive subjects (22–40 y, 6~ m), using an ammonia electrode sensitive to ammonia and amines, and an enzymatic assay specific for ammonia. Continuous aspiration was performed overnight and 220 aspirates were analyzed before and 6~weeks after cure of H. pylori. Gastric samples were diluted 1:3 (before cure) and 1:1 (after cure) according to dilution curves constructed prior to the assays.Results.Median (95% CI) NH3 detected by the elec‐trode/enzymatic assay were 4.34~m m[4.12–4.61]/4.50~m m [4.28–4.68] (p~>~.05) before cure and 0.54~m m[0.42–0.60]/0.73~m m[0.71–0.81] after cure (p~>~.05). Intra‐class correlation coeffi...
It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacte... more It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacter pylori positive subjects than in H pylori negative subjects. This study aimed to investigate the effect of curing H pyloni on the intragastric pH in both the presence and absence of omeprazole therapy. Twenty four hour intragastric pH recordings were performed before and after a one week course of omeprazole (20 mg once daily) in 18 H pyloni positive subjects and were repeated after the infection had been cured. In the absence of omeprazole, the total 24 hour pH values before cure did not differ from those afterwards. During omeprazole treatment the 24 hour pH values were much higher before (median (95% CI) 5.4: 4.3, 6.0), than after cure of infection (3.6: 2.1, 4.4; p<0.001). The omeprazole induced fall in H' activity before cure of H pylorn did not, however, differ from that afterwards. It is concluded that the apparently greater antisecretory effect of omeprazole during H pylorn infection may be a result of the production of acid neutralising compounds by the H pylorn. Although a direct interaction between H pylori and omeprazole cannot be excluded, it seems unlikely.
Previous studies have suggested that profound inhibition of gastric acid secretion may increase e... more Previous studies have suggested that profound inhibition of gastric acid secretion may increase exposure to potentially carcinogenic N-nitroso compounds. The aim of this study was to find out if the proton pump inhibitor omeprazole (20 mg daily) is associated with increased concentrations of potentially carcinogenic N-nitroso compounds in gastric juice. The volume of gastric contents, number of bacteria, and concentrations of nitrates, nitrites, and N-nitroso compounds was determined in gastric aspirates obtained after an overnight fast in 14 healthy volunteers (7M:7F) after one week of treatment with placebo, and one and two weeks' treatment with omeprazole. Median bacterial concentrations were 1*Ox 104 (range 5 0 x 103-5-0 x 106) colony forming units (CFU)/ml after one weeks' treatment with placebo and increased significantly to 4-OX105 (0-3.3x 107) CFU/ml after two weeks' treatment with omeprazole (p<0.05). A similar increase was seen in the concentration of nitrate reducing bacteria. There was no difference in the volume of gastric aspirates after treatment with omeprazole when compared with placebo (65 (29-155) ml v 42 (19-194) ml). The concentration of N-nitroso compounds was 0-13 (0-1-0) ptmol/l after two weeks of omeprazole, which was not significantly different from that seen with placebo (0-15 (0-0.61) tmol/l). There was also no increase in the concentrations of nitrates or nitrites. It is concluded that omeprazole (20 mg once daily) for two weeks in healthy volunteers is associated with gastric bacterial proliferation but does not increase concentrations of N-nitroso compounds.
ABSTRACT It has been shown that omeprazole treatment produces higher intragastric pH values in He... more ABSTRACT It has been shown that omeprazole treatment produces higher intragastric pH values in Helicobacter pylori positive subjects than in H pylori negative subjects. This study aimed to investigate the effect of curing H pylori on the intragastric pH in both the presence and absence of omeprazole therapy. Twenty four hour intragastric pH recordings were performed before and after a one week course of omeprazole (20 mg once daily) in 18 H pylori positive subjects and were repeated after the infection had been cured. In the absence of omeprazole, the total 24 hour pH values before cure did not differ from those afterwards. During omeprazole treatment the 24 hour pH values were much higher before (median (95% CI) 5.4: 4.3, 6.0), than after cure of infection (3.6: 2.1, 4.4; p &lt; 0.001). The omeprazole induced fall in H+ activity before cure of H pylori did not, however, differ from that afterwards. It is concluded that the apparently greater antisecretory effect of omeprazole during H pylori infection may be a result of the production of acid neutralising compounds by the H pylori. Although a direct interaction between H pylori and omeprazole cannot be excluded, it seems unlikely.
relative to the control cells. IL-8 was up-regulated by 19.4 ± 4.2 fold (P < 0.01), TNF was up-re... more relative to the control cells. IL-8 was up-regulated by 19.4 ± 4.2 fold (P < 0.01), TNF was up-regulated 5.6 ± 0.6 fold (P < 0.01), when the C2BBe1 cells treated with Stav relative to the controls. In the SW-620 cell line IFN-α and IFN-β were upregulated (3.3 ± 0.7 fold (P<0.05) and 3.2 ± 0.8 fold (P<0.05) respectively) when treated with Carlow VLP's. When SW-620 were treated with Stav VLP's IL-8 and IL-12 were upregulated (1.8 ± 0.08 fold (P< 0.05) and 3.5 ± 0.46 fold (P<0.01). Furthermore TLR-2, is up-regulated (2.4 ± 0.4 fold (P<0.05)) in SW-620 when treated with Carlow VLP's. Summary: These results show the utility of FUT2 expressing cell lines in the study of NoV infection and suggest that differential immune activation patterns are associated with susceptability to this virus. Further studies are warranted to investigate the involvement of TLR's in this phenomenon.
Background: Transglutaminase 2 (TG2) is a multifunctional protein with transamidase as well as si... more Background: Transglutaminase 2 (TG2) is a multifunctional protein with transamidase as well as signaling activities. Its aberrant catalytic activity has been implicated in the pathogenesis of celiac sprue. However, the physiological role of TG2 and the mechanisms for its In Vivo activation in the small intestine are largely unknown. Aims: To study the TG2 catalytic activity under basal conditions and to identify signals that induce TG2 activity. Methods: We used selective TG2 inhibitors and tagged nucleophilic substrates to monitor the In Vivo TG2 activity during experimental conditions such as fibroblast scratch assay or methotrexate and polyinosinic-polycytidylic acid (poly(I:C)) administration in mice. Results: The majority of TG2 is inactive under normal physiological conditions in cell culture and In Vivo. However, abundant TG2 activity can be detected around the wound in a standard cultured fibroblast scratch assay. To induce tissue injury model in mice, we used methotrexate and poly(I:C), since they trigger small intestinal injury characterized by villous atrophy similar to celiac sprue. The acute poly(I:C) injury model, but not the methotrexate model, resulted in activation of the small intestinal TG2 and in cellular protein crosslinking. Conclusions: Extracellular TG2 is predominantly inactive under physiological conditions. It is activated upon tissue injury or in response to innate immune signals such us poly (I:C). Our results illustrate a new tool to investigate the biology of TG2 in the small intestine. They also provide convenient assays for evaluating small molecule inhibitors of extracellular TG2 activity In Vitro and In Vivo.
See Covering the Cover synopsis on page 409. BACKGROUND & AIMS: Alterations in the microbial comp... more See Covering the Cover synopsis on page 409. BACKGROUND & AIMS: Alterations in the microbial composition of the gastrointestinal tract (dysbiosis) are believed to contribute to inflammatory and functional bowel disorders and psychiatric comorbidities. We examined whether the intestinal microbiota affects behavior and brain biochemistry in mice. METHODS: Specific pathogen-free (SPF) BALB/c mice, with or without subdiaphragmatic vagotomy or chemical sympathectomy, or germ-free BALB/c mice received a mixture of nonabsorbable antimicrobials (neomycin, bacitracin, and pimaricin) in their drinking water for 7 days. Germ-free BALB/c and NIH Swiss mice were colonized with microbiota from SPF NIH Swiss or BALB/c mice. Behavior was evaluated using step-down and light preference tests. Gastrointestinal microbiota were assessed using denaturing gradient gel electrophoresis and sequencing. Gut samples were analyzed by histologic, myeloperoxidase, and cytokine analyses; levels of serotonin, noradrenaline, dopamine, and brain-derived neurotropic factor (BDNF) were assessed by enzymelinked immunosorbent assay. RESULTS: Administration of oral antimicrobials to SPF mice transiently altered the composition of the microbiota and increased exploratory behavior and hippocampal expression of BDNF. These changes were independent of inflammatory activity, changes in levels of gastrointestinal neurotransmitters, and vagal or sympathetic integrity. Intraperitoneal administration of antimicrobials to SPF mice or oral administration to germ-free mice did not affect behavior. Colonization of germ-free BALB/c mice with microbiota from NIH Swiss mice increased exploratory behavior and hippocampal levels of BDNF, whereas colonization of germfree NIH Swiss mice with BALB/c microbiota reduced exploratory behavior. CONCLUSIONS: The intestinal microbiota influences brain chemistry and behavior independently of the autonomic nervous system, gastrointestinal-specific neurotransmitters, or inflammation. Intestinal dysbiosis might contribute to psychiatric disorders in patients with bowel disorders.
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2008
Bacterial infection can trigger the development of functional GI disease. Here, we investigate th... more Bacterial infection can trigger the development of functional GI disease. Here, we investigate the role of the gut-brain axis in gastric dysfunction during and after chronic H. pylori infection. Control and chronically H. pylori-infected Balb/c mice were studied before and 2 mo after bacterial eradication. Gastric motility and emptying were investigated using videofluoroscopy image analysis. Gastric mechanical viscerosensitivity was assessed by cardioautonomic responses to distension. Feeding patterns were recorded by a computer-assisted system. Plasma leptin, ghrelin, and CCK levels were measured using ELISA. IL-1β, TNF-α, proopiomelanocortin (POMC), and neuropeptide Y mRNAs were assessed by in situ hybridizations on frozen brain sections. Gastric inflammation was assessed by histology and immunohistochemistry. As shown previously, H. pylori-infected mice ate more frequently than controls but consumed less food per bout, maintaining normal body weight. Abnormal feeding behavior was...
American Journal of Physiology-Gastrointestinal and Liver Physiology, 2008
The role of chronic infections, such as Helicobacter pylori ( Hp), to produce sustained changes i... more The role of chronic infections, such as Helicobacter pylori ( Hp), to produce sustained changes in host physiology remains controversial. In this study, we investigate whether the antigenic or bacterial content of the gut, after Hp eradication, influences the changes in gut function induced by chronic Hp infection. Mice were infected with Hp for 4 mo and then treated with antibiotics or placebo for 2 wk. Gastric emptying was measured using videofluoroscopy, feeding behavior using a 24-h feeding system, and intestinal permeability using an isolated jejunal segment arterially perfused with an artificial oxygen carrier, hemoglobin vesicles. Immune responses were assessed by CD3+cell counts and anti- Hp antibodies using ELISA. To determine the role of luminal factors in host physiology posteradication, groups of mice received the probiotics containing Lactobacillus rhamnosus R0011 and L. helveticus R0052 or placebo for 2 wk or crude Hp antigen weekly for 2 mo. Chronic Hp infection was a...
Systemic administration of polyinosinic:polycytidylic acid (poly I:C), mimics virally-induced act... more Systemic administration of polyinosinic:polycytidylic acid (poly I:C), mimics virally-induced activation of TLR3 signalling causing acute small intestine damage, but whether and how mucosal administration of poly I:C causes enteropathy is less clear. Our aim was to investigate the inflammatory pathways elicited after intraluminal administration of poly I:C and determine acute and delayed consequences of this locally induced immune activation. Intraluminal poly I:C induced rapid mucosal immune activation in C57BL/6 mice involving IFNb and the CXCL10/CXCR3 axis, that may drive inflammation towards a Th1 profile. Intraluminal poly I:C also caused enteropathy and gut dysfunction in gliadin-sensitive NOD-DQ8 mice, and this was prolonged by concomitant oral administration of gliadin. Our results indicate that small intestine pathology can be induced in mice by intraluminal administration of poly I:C and that this is exacerbated by subsequent oral delivery of a relevant dietary antigen.
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Papers by Elena Verdu