• Relationships between taurine-conjugated bile acids and gut microorganisms and ulcerative colitis (UC), colon cancer, and inflammatory bowel disease (IBD)
  • Pouria Khodaei Ataloo,1,*
    1. Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran


  • Introduction: The prevalence of inflammatory bowel disease (IBD), a chronic, idiopathic gastrointestinal disorder that causes Crohn's disease (CD) and ulcerative colitis (UC), has increased recently. Hepatocytes produce bile acids (BAs) from cholesterol, which are then amidated with taurine or glycine and discharged into the duodenum as bile salts (BSs). Due to dietary influences, the glycine-to-taurine ratios of BSs varied among various regional groups. Disease is specifically linked to varying ratios of taurine and glycine conjugations to BAs. Numerous illnesses, including hepatocellular and cholangiocellular carcinoma, IBD, UC, and colon cancer, have been linked in studies to the metabolism of secondary BSs produced by intestinal bacterial invaders. Bacterial species that may use hydrolases to deconjugate BSs include Listeria, Clostridium, Bifidobacterium, and Bacteroides. This releases taurine, glycine, and their corresponding BAs into the intestinal environment. Unusual sulfur metabolism in the colon may result from increased taurine BS deconjugations in enteric bacterial transformations, which may induce illness. The endpoint's excess hydrogen sulfide (H2S) generation is the main cause of both colorectal cancer and IBD. Enhanced H2S generation, inflammation, toxic levels, and an elevated risk of colon cancer can result from Bilophila wadsworthia proliferation brought on by taurine's enhanced deconjugation from primary and secondary BSs. Colorectal cancer is largely caused by the deoxycholate generation of cholic acid, which is a strong pro-inflammatory signal that is aided by taurocholate deconjugation by Clostridium spp.
  • Methods: In this review article, after searching the PubMed, Scopus, and Google Scholar databases, relevant articles from 2014 to 2024 were selected. Accordingly, the role of colon cancer, IBD, and UC, which are due to increased production of H₂S and its increased deconjugation from primary and secondary BSs due to the abundance of taurine, has been examined.
  • Results: The human colon microbiome still contains taurine-reducing sulfate genes produced by novel species, and a group of microbial sulfide-producing genes is linked to colorectal cancer. While taurine provides sulfite, which B. wadsworthia utilizes as fuel to develop, glycine is digested by Clostridium spp. It's interesting to note that a diet high in saturated fat improves the conjugation of taurine with liver bile acids, which in turn encourages the development of B. wadsworthia and exacerbates colitis.
  • Conclusion: Taurine distribution to gut bacteria may depend on taurine conjugation to bile acids. Under oxidative stress, taurine may be used by microorganisms to create sulfate, which supports the creation of sulfomucin and heme, which can then be converted to the antioxidant bilirubin. Taurine transporters, which are necessary for the β-oxidation of fatty acids and antioxidant defenses, are produced in large quantities by cancer cells. Taurine, particularly its derivative N-chlorotaurine (NCT), assists in normal and cancer cell survival by increasing HO-1, which may lead to inadequate lipid turnover for cancer cell proliferation.
  • Keywords: Conjugated bile acids taurine, Gut microbes, Inflammatory bowel disease, Colon cancer