Abstract: Background: Enterohemorrhagic E. coli (EHEC) can cause acute colitis in dogs, which can lead to hemorrhagic diarrhea and a hemolytic uremic syndrome similar to those in humans. Understanding of the pathophysiology and treatment recommendations are hampered by the lack of translatable in vitro models which effectively reproduce canine and human clinical disease induced by EHEC.
Objectives: To investigate the effects of EHEC on canine intestinal epithelium using organoid-derived monolayers.
Animals and Methods: Colonoid-derived monolayers were developed using intestinal tissues biopsied from two healthy client-owned dogs. The monolayers were challenged with EHEC at 1x106 CFU/ml for 24 hours and impacts of EHEC on epithelial cells were evaluated by trans-epithelial electrical resistance (TEER) measurement, immunofluorescence (IF) staining and scanning electron microscopy (SEM). The results were analyzed using Student t-tests.
Results: The TEER declined significantly in EHEC-infected monolayers after 12 hours compared with that noted in the controls (-24.2% vs -6.3%; p< 0.05). An impact of EHEC on the cellular integrity was confirmed by 1.8-fold increase in E-cadherin expression per unit area with IF staining (p < 0.01). WGA stain confirmed significantly decreased mucus on the EHEC-exposed epithelial surface (-18%, p< 0.05). Attaching/effacing lesions characteristic of EHEC infection were confirmed by SEM imaging.
Conclusions and clinical importance: The results recapitulated in vivo observations reported in dogs and humans with EHEC enteropathy, supporting that the canine colonoid-derived monolayer system can serve as a useful translational model to assess the host-pathogen interaction upon exposure to clinically important enteric pathogens such as EHEC.
