Background: The molecular mechanisms underlying obesity-related intestinal dysfunctions remain poorly understood due to the limited availability of relevant animal models and in vitro systems. However, as a spontaneous and naturally occurring large animal model of various human intestinal diseases, dogs have been increasingly recognized as valuable for advancing our understanding of such conditions.
Hypothesis/Objectives: To demonstrate how the canine colonoid (CC) model can be used to assess the direct impact of a high-fat diet (HFD) on intestinal function.
Animals: Canine colonoids (CCs) were obtained by biopsying colonic tissues from healthy donor dogs at the Veterinary Teaching Hospital at Washington State University.
Methods: The HFD-induced stem-cell phenotype was determined in CCs after 24 hours of palmitic acid (PA) exposure, a well-established main component of the HFD, using RT-qPCR and the EdU assay. The HFD-induced gut epithelial integrity was determined by assessing the transepithelial electrical resistance (TEER) value after 24 hours of PA exposure using colonoid-derived intestinal monolayers. Results were evaluated by ANOVA and t-tests.
Results: Results: Significant increases in LGR5 expression (1.7 times, p< 0.01) as well as the size of organoids (3.0 times, p< 0.01) and the percentage of EdU-positive cells (2.7 times, p< 0.01) were confirmed following PA exposure. In colonoid-derived intestinal monolayers, significant decrease in TEER values (p< 0.01) was demonstrated following PA exposure.
Conclusions and clinical importance: We confirmed exposure to PA increased the stemness of CCs and reduced the barrier function, recapitulating the findings in dogs and humans following HFD consumption. These studies establish proof-of-concept that CCs can be utilized to assess the effect of early exposure of a nutrient on intestinal function.
.jpg "Itsuma Nagao, DVM photo")
