1.
Standard colonic lavage alters the natural state of mucosal-associated microbiota in the human colon.
Harrell, L, Wang, Y, Antonopoulos, D, Young, V, Lichtenstein, L, Huang, Y, Hanauer, S, Chang, E
PloS one. 2012;(2):e32545
Abstract
BACKGROUND & AIMS Past studies of the human intestinal microbiota are potentially confounded by the common practice of using bowel-cleansing preparations. We examined if colonic lavage changes the natural state of enteric mucosal-adherent microbes in healthy human subjects. METHODS Twelve healthy individuals were divided into three groups; experimental group, control group one, and control group two. Subjects in the experimental group underwent an un-prepped flexible sigmoidoscopy with biopsies. Within two weeks, subjects were given a standard polyethylene glycol-based bowel cleansing preparation followed by a second flexible sigmoidoscopy. Subjects in control group one underwent two un-prepped flexible sigmoidoscopies within one week. Subjects in the second control group underwent an un-prepped flexible sigmoidoscopy followed by a second flexible sigmoidoscopy after a 24-hour clear liquid diet within one week. The mucosa-associated microbial communities from the two procedures in each subject were compared using 16S rRNA gene based terminal restriction fragment length polymorphism (T-RFLP), and library cloning and sequencing. RESULTS Clone library sequencing analysis showed that there were changes in the composition of the mucosa-associated microbiota in subjects after colonic lavage. These changes were not observed in our control groups. Standard bowel preparation altered the diversity of mucosa-associated microbiota. Taxonomic classification did not reveal significant changes at the phylum level, but there were differences observed at the genus level. CONCLUSION Standard bowel cleansing preparation altered the mucosal-adherent microbiota in all of our subjects, although the degree of change was variable. These findings underscore the importance of considering the confounding effects of bowel preparation when designing experiments exploring the gut microbiota.
2.
A new oral formulation for the release of sodium butyrate in the ileo-cecal region and colon.
Roda, A, Simoni, P, Magliulo, M, Nanni, P, Baraldini, M, Roda, G, Roda, E
World journal of gastroenterology. 2007;(7):1079-84
Abstract
AIM: To develop a new formulation with hydroxy propyl methyl cellulose and Shellac coating for extended and selective delivery of butyrate in the ileo-caecal region and colon. METHODS One-gram sodium butyrate coated tablets containing 13C-butyrate were orally administered to 12 healthy subjects and 12 Crohn's disease patients and the rate of 13C-butyrate absorption was evaluated by 13CO2 breath test analysis for eight hours. Tauroursodeoxycholic acid (500 mg) was co-administered as a biomarker of oro-ileal transit time to determine also the site of release and absorption of butyrate by the time of its serum maximum concentration. RESULTS The coated formulation delayed the 13C-butyrate release by 2-3 h with respect to the uncoated tablets. Sodium butyrate was delivered in the intestine of all subjects and a more variable transit time was found in Crohn's disease patients than in healthy subjects. The variability of the peak 13CO2 in the kinetic release of butyrate was explained by the inter-subject variability in transit time. However, the coating chosen ensured an efficient release of the active compound even in patients with a short transit time. CONCLUSION Simultaneous evaluation of breath 13CO2 and tauroursodeoxycholic acid concentration-time curves has shown that the new oral formulation consistently releases sodium butyrate in the ileo-cecal region and colon both in healthy subjects and Crohn's disease patients with variable intestinal transit time. This formulation may be of therapeutic value in inflammatory bowel disease patients due to the appropriate release of the active compound.
3.
Colonic fermentation influences lower esophageal sphincter function in gastroesophageal reflux disease.
Piche, T, des Varannes, SB, Sacher-Huvelin, S, Holst, JJ, Cuber, JC, Galmiche, JP
Gastroenterology. 2003;(4):894-902
Abstract
BACKGROUND & AIMS Colonic fermentation of carbohydrates is known to influence gastric and esophageal motility in healthy subjects. This study investigated the effects of colonic fermentation induced by oral administration of fructooligosaccharides (FOS) in patients with gastroesophageal reflux disease (GERD). METHODS In the cross-over design used in the study, 9 patients with symptomatic GERD were administered a low-residue diet (i.e., 10 g fiber/day) during 2, 7-day periods, receiving either 6.6 g of FOS or placebo 3 times daily after meals. Each period was separated by a wash out of at least 3 weeks. On day 7, esophageal motility and pH were recorded in fasting conditions and after a test meal containing 6.6 g of FOS or placebo. Breath hydrogen concentrations (reflecting colonic fermentation) and plasma concentrations of glucagon-like peptide 1 (GLP-1), peptide YY, and cholecystokinin were monitored. RESULTS Compared with placebo, FOS led to a significant increase in the number of transient lower esophageal sphincter relaxations (TLESRs) and reflux episodes, esophageal acid exposure, and the symptom score for GERD. The integrated plasma response of GLP-1 was significantly higher after FOS than placebo. CONCLUSIONS Colonic fermentation of indigestible carbohydrates increases the rate of TLESRs, the number of acid reflux episodes, and the symptoms of GERD. Although different mechanisms are likely to be involved, excess release of GLP-1 may account, at least in part, for these effects.
4.
Pharmacokinetic evaluation of guar gum-based colon-targeted oral drug delivery systems of metronidazole in healthy volunteers.
Krishnaiah, YS, Veer Raju, P, Dinesh Kumar, B, Jayaram, B, Rama, B, Raju, V, Bhaskar, P
European journal of drug metabolism and pharmacokinetics. 2003;(4):287-94
Abstract
The present study was carried out to find the in vivo performance of guar gum-based colon-targeted tablets of metronidazole as compared to an immediate release tablets in human volunteers. Six healthy volunteers participated in the study and a crossover design was used. Blood samples were obtained at different time intervals and the plasma concentration of metronidazole was estimated by reverse phase HPLC. The immediate release tablets of metronidazole produced peak plasma concentration (Cmax of 2990 +/- 574.6 ng/mL) within 2.8 +/- 0.6 h. On oral administration of colon-targeted tablets, metronidazole started appearing in the plasma between 5 h and 8 h, and reached the peak concentration (Cmax of 1940.0 +/- 528.4 ng/mL) at 11.1 +/- 2.1 h (Tmax). The AUC(0-infinity) and t(1/2) of metronidazole were unaltered on administering the drug as a colon-targeted tablet indicating that the extent of absorption and elimination were not affected by targeting the drug to the colon. However, colon-targeted tablets showed delayed tmax and absorption time (ta), decreased Cmax and decreased absorption rate constant as compared to immediate release tablets. This in turn indicated that metronidazole was delivered to the colon resulting in a slow absorption of the drug and making it available for local action in the colon.