Human enteroids as an ex-vivo model of host-pathogen interactions in the gastrointestinal tract

Currently, 9 out of 10 experimental drugs fail in clinical studies. This has caused a 40% plunge in the number of drugs approved by the US Food and Drug Administration (FDA) since 2005. It has been suggested that the mechanistic differences between human diseases modeled in animals (mostly rodents) and the pathophysiology of human diseases might be one of the critical factors that contribute to drug failure in clinical trials. Rapid progress in the field of human stem cell technology has allowed the in-vitro recreation of human tissue that should complement and expand upon the limitations of cell and animal models currently used to study human diseases and drug toxicity. Recent success in the identification and isolation of human intestinal epithelial stem cells (Lgr5(+)) from the small intestine and colon has led to culture of functional intestinal epithelial units termed organoids or enteroids. Intestinal enteroids are comprised of all four types of normal epithelial cells and develop a crypt-villus differentiation axis. They demonstrate major intestinal physiologic functions, including Na(+) absorption and Cl(-) secretion. This review discusses the recent progress in establishing human enteroids as a model of infectious diarrheal diseases such as cholera, rotavirus, and enterohemorrhagic Escherichia coli, and use of the enteroids to determine ways to correct the diarrhea-induced ion transport abnormalities via drug therapy.