CH₄, H₂S, and H₂O: How Do They Relate to Microbiome-Driven IBS Pathogenesis?

Excerpt

The human intestinal microbiome consists of a dense and complex multi-kingdom ecosystem containing bacteria, fungi, archæa, protists, and viruses that have profound effects on the health of their host. The pathogenesis of irritable bowel syndrome (IBS), and more broadly, functional gastrointestinal diseases (FGID), has been linked to the composition and functions of the intestinal microbiome.^{1, 2} Since the transfer of fecal microbiota from individuals with IBS confers some symptoms to animal models,^{3, 4} alterations in microbial composition are likely to have functional consequences. Clinical evidence for microbiome involvement includes IBS symptom improvement with antibiotic treatment in patients without constipation.⁵ Furthermore, patients with positive hydrogen breath testing, a measure of microbiome fermentation, have a more marked response rate to antibiotics.⁶ Antibiotic treatment targeted to reduce methane (CH₄) production associated with constipation-predominant IBS reduces symptoms.⁷ Targeting the microbial alterations characteristic of patients with IBS via fecal microbiota transplant (FMT) has yielded promising, albeit mixed results.⁸ …