The Protective Effect of Roseburia faecis Against Repeated Water Avoidance Stress-induced Irritable Bowel Syndrome in a Wister Rat Model

Roseburia faecis, a butyrate-producing, gram-positive anaerobic bacterium, was evaluated for its usefulness against repeated water avoidance stress (WAS)-induced irritable bowel syndrome (IBS) in a rat model, and the underlying mechanism was explored.We divided the subjects into three groups: one without stress exposure, another subjected to daily 1-hour WAS for 10 days, and a third exposed to the same WAS regimen while also receiving two different R. faecis strains (BBH024 or R22-12-24) via oral gavage for the same 10-day duration. Fecal pellet output (FPO), a toluidine blue assay for mast cell infiltration, and fecal microbiota analyses were conducted using 16S rRNA metagenomic sequencing. Predictive functional profiling of microbial communities in metabolism was also conducted. FPO and colonic mucosal mast cell counts were significantly higher in the WAS group than in the control group (male, P = 0.004; female, P = 0.027). The administration of both BBH024 (male, P = 0.015; female, P = 0.022) and R22-12-24 (male, P = 0.003; female, P = 0.040) significantly reduced FPO. Submucosal mast cell infiltration in the colon showed a similar pattern in males. In case of fecal microbiota, the WAS with R. faecis group showed increased abundance of the Roseburia genus compared to WAS alone. Moreover, the expression of a gene encoding a D-methionine transport system substrate-binding protein was significantly elevated in the WAS with R. faecis group compared to that in the WAS (male, P = 0.028; female, P = 0.025) group. These results indicate that R. faecis is a useful probiotic for treating IBS and colonic microinflammation.

Changes in Cecal Microbiota and Short-chain Fatty Acid During Lifespan of the Rat

Background/Aims@#The gut microbiota regulates intestinal immune homeostasis through host-microbiota interactions. Multiple factors affect the gut microbiota, including age, sex, diet, and use of drugs. In addition, information on gut microbiota differs depending on the samples.The aim of this study is to investigate whether changes in cecal microbiota depend on aging. @*Methods@#Gut microbiota in cecal contents of 6-, 31-, and 74-week-old and 2-year-old male Fischer-344 rats (corresponding to 5-, 30-, 60-, and 80-year-old humans in terms of age) were analyzed using 16S ribosomal RNA metagenome sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) based on the Kyoto Encyclopedia of Genes and Genomes orthology.Moreover, short-chain fatty acid (SCFA) level in cecum and inflammation related factors were measured using real-time quantitative polymerase chain reaction and enzyme linked immunosorbent assay. @*Results@#Alpha and beta diversity did not change significantly with age. At the family level, Lachnospiraceae and Ruminococcaceae, which produce SCFAs, showed significant change in 31-week-old rats: Lachnospiraceae significantly increased at 31 weeks of age, compared to other age groups, while Ruminococcaceae decreased. Butyrate levels in cecum were significantly increased in 31-week-old rats, and the expression of inflammation related genes was increased followed aging. Especially, EU622775_s and EU622773_s, which were highly abundance species in 31-week-old rats, showed significant relationship with butyrate concentration. Enzymes required for producing butyrate—acetyl-CoA transferase, butyryl-CoA dehydrogenase, and butyrate kinase—were not predicted by PICRUSt. @*Conclusions@#Major bacterial taxa in the cecal lumen, such as Lachnospiraceae, well-known SCFAs-producing family, changed in 31-week-old rats.Moreover, unknown species EU622775_s and EU622773_s showed strong association with cecal butyrate level at 31 weeks of age.

Rat Intestinal Acetic Acid and Butyric acid and Effects of Age, Sex, and High-fat Diet on the Intestinal Levels in Rats

BACKGROUND: High-fat diet is known to be implicated in the pathogenesis of various metabolic disorders related to an inflammatory response. The aim of this study was to investigate the influence of high-fat diet for intestinal acetic acid and butyric acid concentrations which are related to inflammation-associated colon cancer risk. METHODS: Both male and female rats of 6, 31, 74 and 104-week of age were fed chow diet or high-fat diet for 8 weeks. Body weight and food intake were measured weekly during the feeding period. Intestinal acetic acid and butyric acid levels were measured by high-performance liquid chromatography from luminal contents of ileum and cecum. RESULTS: Male rats showed greater weight change than female rats in every age. Calorie-adjusted food intake was also higher in male rats compared to female rats. Male rats showed similar intake of food in every age while 31-week old female rats showed increased intake, which was decreased at 74-week and 104-week of age. The ileal acetic acid concentration was increased in male rats fed high-fat diet, while female rats fed high-fat diet showed no significant change in the ileal acetic acid level. On the other hand, butyric acid almost disappeared in high-fat diet fed rats regardless of sex. CONCLUSIONS: High-fat diet increases the intestinal acetic acid concentration while reducing the butyric acid concentration which may account for increased risk of inflammation-associated colon cancer.

Analysis of Gastric Body Microbiota by Pyrosequencing: Possible Role of Bacteria Other Than Helicobacter pylori in the Gastric Carcinogenesis

BACKGROUND: Gastric microbiota along with Helicobacter pylori (HP) plays a key role in gastric disease. The aim of our study is to investigate the difference of human gastric microbiota between antrum and body according to disease (control vs. gastric cancer) and HP status. METHODS: Each antrum and body biopsy was collected from 12 subjects at Seoul National University Bundang Hospital. Gastric microbiota was analyzed by bar-coded 454 pyrosequencing of the 16S rRNA gene. Twelve subjects consisted of HP-negative control (n = 2), HP-negative cancer (n = 2), HP-positive control (n = 3), and HP-positive cancer (n = 5). The analysis was focused on non-HP urease-producing bacteria (UB) and non-HP nitrosating or nitroreducing bacteria (NB) between antrum and body. RESULTS: Gastric body samples showed higher diversity compared to gastric antrum mucosa samples but there was no significant difference. The mean of operational taxonomic units was higher in HP(−) cancer than HP(+) cancer (antrum, 273.5 vs. 228.2, P = 0.439; body, 585.5 vs. 183.2, P = 0.053). The number of non-HP UB and non-HP NB was higher in HP(−) cancer groups than the others. These differences were more pronounced in the body (P = 0.051 and P = 0.081, respectively). Analysis of overlap of non-HP UB and non-HP NB revealed the higher composition of Streptococcus pseudopneumoniae, S. parasanguinis, and S. oralis in HP(−) cancer groups than the others, only in the body (P = 0.030) but not in the antrum (P = 0.123). CONCLUSIONS: Higher diversity and higher composition of S. pseudopneumoniae, S. parasanguinis, and S. oralis in HP(−) cancer group than the other groups in the body suggest that analysis of microbiota from body mucosa could be beneficial to identify a role of non-HP bacteria in the gastric carcinogenesis.

Analysis of Gastric Body Microbiota by Pyrosequencing: Possible Role of Bacteria Other Than Helicobacter pylori in the Gastric Carcinogenesis

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Impact of Long-Term Proton Pump Inhibitor Therapy on Gut Microbiota in F344 Rats: Pilot Study

BACKGROUND/AIMS: To evaluate changes in gut microbiota composition following long-term proton pump inhibitor (PPI) treatment. METHODS: Twenty-four-week-old F344 rats were fed diets with (n=6) or without (n=5) lansoprazole for 50 weeks. Profiles of luminal microbiota in the terminal ileum were then analyzed. Pyrosequencing of the 16S rRNA gene was performed using an FLX genome sequencer (454 Life Sciences/Roche). RESULTS: Rats treated with lansoprazole showed significantly reduced body weights compared to controls (lansoprazole-treated rats and controls, 322.3±15.3 g vs 403.2±5.2 g, respectively, p<0.001). However, stool frequencies and consistencies did not differ between the two groups. The composition of the gut microbiota in lansoprazole-treated rats was quite different from that of the controls. In the controls, the microbiota profiles obtained from the terminal ileum showed a predominance of Proteobacteria (93.9%) due to the abundance of Escherichia and Pasteurella genera. Conversely, lansoprazole-treated rats showed an elevated population of Firmicutes (66.9%), which was attributed to an increased ratio of Clostridium g4 to Lactobacillus genera. CONCLUSIONS: This preliminary study suggests that long-term administration of PPI may cause weight loss and changes to the microbiota in the terminal ileum.

Impact of Long-Term Proton Pump Inhibitor Therapy on Gut Microbiota in F344 Rats: Pilot Study

BACKGROUND/AIMS: To evaluate changes in gut microbiota composition following long-term proton pump inhibitor (PPI) treatment. METHODS: Twenty-four-week-old F344 rats were fed diets with (n=6) or without (n=5) lansoprazole for 50 weeks. Profiles of luminal microbiota in the terminal ileum were then analyzed. Pyrosequencing of the 16S rRNA gene was performed using an FLX genome sequencer (454 Life Sciences/Roche). RESULTS: Rats treated with lansoprazole showed significantly reduced body weights compared to controls (lansoprazole-treated rats and controls, 322.3±15.3 g vs 403.2±5.2 g, respectively, p<0.001). However, stool frequencies and consistencies did not differ between the two groups. The composition of the gut microbiota in lansoprazole-treated rats was quite different from that of the controls. In the controls, the microbiota profiles obtained from the terminal ileum showed a predominance of Proteobacteria (93.9%) due to the abundance of Escherichia and Pasteurella genera. Conversely, lansoprazole-treated rats showed an elevated population of Firmicutes (66.9%), which was attributed to an increased ratio of Clostridium g4 to Lactobacillus genera. CONCLUSIONS: This preliminary study suggests that long-term administration of PPI may cause weight loss and changes to the microbiota in the terminal ileum.

Comparison of Gastric Microbiota Between Gastric Juice and Mucosa by Next Generation Sequencing Method

BACKGROUND: Not much is known about the role of gastric microbiota except for Helicobacter pylori in human health and disease. In this study, we aimed to detect human gastric microbiota in both gastric mucosa and gastric juice by barcoded 454-pyrosequencing of the 16S rRNA gene and to compare the results from mucosa and juice. METHODS: Gastric biopsies and stomach juices were collected from 4 subjects who underwent standard endoscopy at Seoul National University Bundang Hospital. Gastric microbiota of antral mucosa, corpus mucosa samples, and gastric fluids were analyzed by barcoded 454-pyrosequencing of the 16S rRNA gene. The analysis focused on bacteria, such as H. pylori and nitrosating or nitrate-reducing bacteria. RESULTS: Gastric fluid samples showed higher diversity compared to that of gastric mucosa samples. The mean of operational taxonomic units was higher in gastric fluid than in gastric mucosa. The samples of gastric fluid and gastric mucosa showed different composition of phyla. The composition of H. pylori and Proteobacteria was higher in mucosa samples compared to gastric fluid samples (H. pylori, 66.5% vs. 3.3%, P = 0.033; Proteobacteria, 75.4% vs. 26.3%, P = 0.041), while Actinobacteria, Bacteroidetes, and Firmicutes were proportioned relatively less in mucosa samples than gastric fluid. However there was no significant difference. (Actinobacteria, 3.5% vs. 20.2%, P = 0.312; Bacteroidetes, 6.0% vs. 14.8%, P = 0.329; Firmicutes, 12.8% vs. 33.4%, P = 0.246). CONCLUSIONS: Even though these samples were small, gastric mucosa could be more effective than gastric fluid in the detection of meaningful gastric microbiota by pyrosequencing.