Microbial modulation of energy availability in the colon regulates intestinal transit.
Gut microbiota contribute to host metabolic efficiency by increasing energy availability through the fermentation of dietary fiber and production of short-chain fatty acids (SCFAs) in the colon. SCFAs are proposed to stimulate secretion of the proglucagon (Gcg)-derived incretin hormone GLP-1, which stimulates insulin secretion (incretin response) and inhibits gastric emptying. We find that germ-free (GF) and antibiotic-treated mice, which have severely reduced SCFA levels, have increased basal GLP-1 levels in the plasma and increased Gcg expression in the colon. Increasing energy supply, either through colonization with polysaccharide-fermenting bacteria or through diet, suppressed colonic Gcg expression in GF mice. Increased GLP-1 levels in GF mice did not improve the incretin response but instead slowed intestinal transit. Thus, microbiota regulate the basal levels of GLP-1, and increasing these levels may be an adaptive response to insufficient energy availability in the colon that slows intestinal transit and allows for greater nutrient absorption.
Wallenberg Laboratory/Sahlgrenska Center for Cardiovascular and Metabolic Research, Sahlgrenska University Hospital, Gothenburg 40530, Sweden; Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg 41345, Sweden.
Anita
A
Wichmann
Ava
A
Allahyar
Thomas U
TU
Greiner
Hubert
H
Plovier
Gunnel Östergren
GÖ
Lundén
Thomas
T
Larsson
Daniel J
DJ
Drucker
Nathalie M
NM
Delzenne
Patrice D
PD
Cani
Fredrik
F
Bäckhed
D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D003106:Colon / Q000382:microbiology*; D004043:Dietary Fiber / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005772:Gastrointestinal Transit; D005856:Germ-Free Life; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D051379:Mice; D052336:Proglucagon / Q000378:metabolism
D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D052336:Proglucagon; D052216:Glucagon-Like Peptide 1