Kang-Hong Lee

Altered intestinal microbiota in irritable bowel syndrome

Abstract  Recent studies have suggested that alterations in the composition of the intestinal microbiota may play an important role in irritable bowel syndrome (IBS) symptoms. However, an association between the composition of the intestinal microbiota and IBS symptoms has not been clearly demonstrated. In the current issue of the Journal, Tana et al. suggest that altered intestinal microbiota contributes to the symptoms of IBS through increased levels of organic acids. In fecal samples, IBS patients had significantly higher numbers of Veillonella and Lactobacillus than healthy controls. They also showed significantly higher levels of acetic acid and propionic acid. Furthermore, IBS patients with high acetic acid or propionic acid levels presented more severe symptoms, impaired quality of life and negative emotions. These results are in accordance with the concept that the gut microbiota influences the sensory, motor and immune system of the gut and interacts with higher brain centers. Small intestinal bacterial overgrowth observed in a subset of IBS patients describes quantitative changes in the small intestinal microbiota. Data on qualitative changes in the gut microbiota in IBS patients are lacking. Different members of gut bacteria may have different influence on gut function. The concepts identified here may lead to the development of novel therapeutic strategies for IBS using manipulation of the intestinal microbiota.

Efficacy of ramosetron in the treatment of male patients with irritable bowel syndrome with diarrhea: a multicenter, randomized clinical trial, compared with mebeverine.

Background  The 5‐HT3 receptor antagonists are known to be effective for the treatment of diarrhea‐predominant irritable bowel syndrome (IBS), but not widely used yet. The aim of this study was to compare the efficacy and safety of ramosetron, a 5‐HT3 receptor antagonist, and mebeverine in male patients with IBS with diarrhea (IBS‐D).

Efficacy of combination therapy with probiotics and mosapride in patients with IBS without diarrhea: a randomized, double‐blind, placebo‐controlled, multicenter, phase II trial

Probiotics can be beneficial in irritable bowel syndrome (IBS). Mosapride citrate, a selective 5‐HT4 receptor agonist, stimulates gastrointestinal motility. We investigated the efficacy of combination therapy with probiotics and mosapride for non‐diarrheal‐type IBS.

The NO/cGMP pathway in duodenal motor, mechano- and chemosensory responses to acid: A randomized, placebo-controlled study with sildenafil in healthy volunteers

Altered duodenal sensorimotor responses to acid have been reported in a subset of patients with functional dyspepsia. To investigate whether NO is involved in these abnormalities, the effect of sildenafil (activates the NO pathway) on duodenal motor and sensory responses to acid in healthy humans was evaluated.