Original Research ARTICLE
The Gut Microbiota Regulates Endocrine Vitamin D Metabolism Through Fibroblast Growth Factor 23.
- 1Pennsylvania State University, United States
To determine the effect of the microbiota on vitamin D metabolism, serum 25hydroxyvitamin D(25D), 24,25dihydroxyvitamin D (24,25D) and 1,25dihydroxyvitamin D (1,25D) were measured in germfree (GF) mice before and after conventionalization (CN). GF mice had low levels of 25D, 24,25D and 1,25D and were hypocalcemic. CN of the GF mice with microbiota, for 2wks recovered 25D, 24,25D and 1,25D levels. Females had more 25D and 24,25D than males both as GF mice and after CN. Introducing a limited number of commensals (8 commensals) increased 25D and 24,25D to the same extent as CN. Monocolonization with the enteric pathogen Citrobacter rodentium increased 25D and 24,25D, but the values only increased after 4 wks of C. rodentium colonization when inflammation resolved. Fibroblast growth factor (FGF)23 was extremely high in GF mice. CN resulted in an increase in TNF-± expression in the colon 2d after CN that coincided with a reduction in FGF23 by 3d that eventually normalized 25D, 24,25D, 1,25D at 1wk post-CN and reinstated calcium homeostasis. Neutralization of FGF23 in GF mice raised 1,25D, without CN, demonstrating that the high FGF23 levels were responsible for the low calcium and 1,25D in GF mice. The microbiota induce inflammation in the GF mice that inhibits FGF23 to eventually reinstate homeostasis that includes increased 25D, 24,25D and 1,25D levels. The microbiota through FGF23 regulates vitamin D metabolism.
Keywords: microbiota, Fibroblast growth factor 23, Vitamin D, Inflammation, tumor necrosis factor-α
Received: 29 Sep 2017;
Accepted: 14 Feb 2018.
Edited by:Raquel Hontecillas, Virginia Tech, United States
Reviewed by:Caroline H. Johnson, Yale School of Public Health, Yale University, United States
Nuria Tubau-Juni, Virginia Tech, United States
Copyright: © 2018 Bora, Kennett, Smith, Patterson and Cantorna. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Margherita Cantorna, Pennsylvania State University, University Park, United States, firstname.lastname@example.org