title: Colonic Absorption of Low-Molecular-Weight Metabolites Influenced by the Intestinal Microbiome: A Pilot Study.
abstract: Low-molecular-weight metabolites produced by the intestinal microbiome play a direct role in health and disease. However, little is known about the ability of the colon to absorb these metabolites. It is also unclear whether these metabolites are bioavailable. Here, metabolomics techniques (capillary electrophoresis with time-of-flight mass spectrometry, CE-TOFMS), germ-free (GF) mice, and colonized (Ex-GF) mice were used to identify the colonic luminal metabolites transported to colonic tissue and/or blood. We focused on the differences in each metabolite between GF and Ex-GF mice to determine the identities of metabolites that are transported to the colon and/or blood. CE-TOFMS identified 170, 246, 166, and 193 metabolites in the colonic feces, colonic tissue, portal plasma, and cardiac plasma, respectively. We classified the metabolites according to the following influencing factors: (i) the membrane transport system of the colonocytes, (ii) metabolism during transcellular transport, and (iii) hepatic metabolism based on the similarity in the ratio of each metabolite between GF and Ex-GF mice and found 62 and 22 metabolites that appeared to be absorbed from the colonic lumen to colonocytes and blood, respectively. For example, 11 basic amino acids were transported to the systemic circulation from the colonic lumen. Furthermore, many low-molecular-weight metabolites influenced by the intestinal microbiome are bioavailable. The present study is the first to report the transportation of metabolites from the colonic lumen to colonocytes and somatic blood in vivo, and the present findings are critical for clarifying host-intestinal bacterial interactions.
authors.affiliation: Dairy Science and Technology Institute, Kyodo Milk Industry Co. Ltd., Hinode-mach, Tokyo, Japan.|Benno Laboratory, Innovation Center, RIKEN, Wako, Japan.
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Human Metabolome Technologies, Inc., Tsuruoka, Japan.
authors.forename: Takushi
authors.initials: T
authors.lastname: Ooga
authors.affiliation: Benno Laboratory, Innovation Center, RIKEN, Wako, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Kibe
authors.affiliation: Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Aiba
authors.affiliation: Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koga
authors.affiliation: Benno Laboratory, Innovation Center, RIKEN, Wako, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Benno
mesh_terms: D000818:Animals; D003106:Colon / Q000378:metabolism* / Q000382:microbiology; D019075:Electrophoresis, Capillary; D005243:Feces / Q000382:microbiology*; D000069196:Gastrointestinal Microbiome; D005856:Germ-Free Life; D013058:Mass Spectrometry; D055432:Metabolomics; D051379:Mice; D008807:Mice, Inbred BALB C; D010865:Pilot Projects