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World J Gastroenterol. Dec 21, 2014; 20(47): 17727-17736
Published online Dec 21, 2014. doi: 10.3748/wjg.v20.i47.17727
Impact of the gut microbiota on rodent models of human disease
Axel Kornerup Hansen, Camilla Hartmann Friis Hansen, Lukasz Krych, Dennis Sandris Nielsen
Axel Kornerup Hansen, Camilla Hartmann Friis Hansen, Section of Experimental Animal Models, Department of Veterinary Disease Biology, University of Copenhagen, 1871 Frederiksberg, Denmark
Lukasz Krych, Dennis Sandris Nielsen, Department of Food Science, Faculty of Sciences, University of Copenhagen, 1958 Frederiksberg, Denmark
Author contributions: All authors contributed to this paper equally.
Correspondence to: Axel Kornerup Hansen, Professor, DVSc, DVM, DipECLAM, Section of Experimental Animal Models, Department of Veterinary Disease Biology, University of Copenhagen, 57 Thorvaldsensvej, 1871 Frederiksberg, Denmark. akh@sund.ku.dk
Telephone: +45-353-32726 Fax: +45-353-32755
Received: February 27, 2014
Revised: September 30, 2014
Accepted: November 18, 2014
Published online: December 21, 2014
Processing time: 296 Days and 4.2 Hours
Abstract

Traditionally bacteria have been considered as either pathogens, commensals or symbionts. The mammal gut harbors 1014 organisms dispersed on approximately 1000 different species. Today, diagnostics, in contrast to previous cultivation techniques, allow the identification of close to 100% of bacterial species. This has revealed that a range of animal models within different research areas, such as diabetes, obesity, cancer, allergy, behavior and colitis, are affected by their gut microbiota. Correlation studies may for some diseases show correlation between gut microbiota composition and disease parameters higher than 70%. Some disease phenotypes may be transferred when recolonizing germ free mice. The mechanistic aspects are not clear, but some examples on how gut bacteria stimulate receptors, metabolism, and immune responses are discussed. A more deeper understanding of the impact of microbiota has its origin in the overall composition of the microbiota and in some newly recognized species, such as Akkermansia muciniphila, Segmented filamentous bacteria and Faecalibacterium prausnitzii, which seem to have an impact on more or less severe disease in specific models. Thus, the impact of the microbiota on animal models is of a magnitude that cannot be ignored in future research. Therefore, either models with specific microbiota must be developed, or the microbiota must be characterized in individual studies and incorporated into data evaluation.

Keywords: Animal models; Gut microbiota; Diabetes; Obesity; Cancer; Allergy; Behavior; Colitis

Core tip: Full characterization of the gut microbiota of animal models has revealed that animal models within different research areas, such as diabetes, obesity, cancer, allergy, behavior and colitis, are highly affected by their gut microbiota. The mechanistic aspects are not clear; however, the impact of the microbiota on animal models is of a magnitude that cannot be ignored in future research. Therefore, either models with specific microbiota must be developed, or the microbiota must be characterized in individual studies and incorporated into data evaluation.