The Microbiota and Gut-Related Disorders: Insights from Animal Models

Abstract

Over the past decade, the scientific committee has called for broadening our horizons in understanding host–microbe interactions and infectious disease progression. Owing to the fact that the human gut harbors trillions of microbes that exhibit various roles including the production of vitamins, absorption of nutrients, pathogen displacement, and development of the host immune system, particular attention has been given to the use of germ-free (GF) animal models in unraveling the effect of the gut microbiota on the physiology and pathophysiology of the host. In this review, we discuss common methods used to generate GF fruit fly, zebrafish, and mice model systems and highlight the use of these GF model organisms in addressing the role of gut-microbiota in gut-related disorders (metabolic diseases, inflammatory bowel disease, and cancer), and in activating host defense mechanisms and amending pathogenic virulence.

Utilizing Probiotics for the Prevention and Treatment of Gastrointestinal Diseases

“…The differences in gastrointestinal anatomy, physiology, and microbiotas are evident, yet the reduced expense and ease of maintaining zebrafish and Drosophila colonies under germ-free (GF) conditions has led to their utilization albeit with limitations ( Kamareddine et al, 2020 ). While human microbiota consists of Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, and Verrucomicrobia, Drosophila are conventionally populated with Proteobacteria and Firmicutes and zebrafish with Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria ( Blum, 2013 ; Xiao, 2015 ; Kamareddine et al, 2020 ). In addition to bacterial species, Drosophila provide the opportunity to study several yeasts (e.g., Candida and Pichia) ( Chandler, 2012 ; Stamps, 2012 ).…”

“…In addition to bacterial species, Drosophila provide the opportunity to study several yeasts (e.g., Candida and Pichia) ( Chandler, 2012 ; Stamps, 2012 ). Drosophila and Zebrafish models can be employed with conventional microbiota or GF with subsequent selective colonization ( Kamareddine et al, 2020 ). As with all GF models, limitations exist regarding food sources that may contain autoclave-resistant microbial products ( Hyun, 1983 ).…”

“…While there are limitations associated with preclinical models to study probiotics and host-specific microbiota interactions, these species provide an avenue for investigating the diverse microbiota ecosystem and unraveling the complex interactions prior to costly and logistically burdensome clinical trials. The differences in gastrointestinal anatomy, physiology, and microbiotas are evident, yet the reduced expense and ease of maintaining zebrafish and Drosophila colonies under germ-free (GF) conditions has led to their utilization albeit with limitations (Kamareddine et al, 2020). While human microbiota consists of Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, and Verrucomicrobia, Drosophila are conventionally populated with Proteobacteria and Firmicutes and zebrafish with Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria (Blum, 2013;Xiao, 2015;Kamareddine et al, 2020).…”

Editorial: Unconventional Animal Models in Infectious Disease Research

“…Owing to the importance of using Drosophila melanogaster in infectious disease research and to our recently achieved groundbreaking findings in host-pathogen interaction studies using the fruit fly model organism (Kamareddine et al, 2018a;Kamareddine et al, 2018b;Jugder et al, 2021), the third contribution to this Research Topic was a review put up by our group to distinctly highlight the importance and advantages of Drosophila as a model organism of choice in host-pathogen interactions studies (Younes et al). Communally, this review, along with others including another review from our group on a similar subject matter (Kamareddine et al, 2020) aim to provide comprehensive insight into the use of animal models in disease research.…”

Managing the Microbiome: How the Gut Influences Development and Disease

“…By contrast, humans derive their microbiome primarily from terrestrial origins, maintain a body temperature nearly ten degrees higher, and could not function without organs such as the lungs. These discrepancies between human and zebrafish physiology greatly limit the direct application of zebrafish studies to clinical research [ 14 ].…”