Fluid Shear Stress Enhances Differentiation of Jejunal Human Enteroids in Intestine-Chip
Background and Aims: There is increasing evidence that study of normal human enteroids duplicates many known aspects of human intestinal physiology. However, this epithelial cell-only model lacks the many non-epithelial intestinal cells present in the gastrointestinal tract and exposure to the mechanical forces to which the intestine is exposed. We tested the hypothesis that physical shear forces produced by luminal and blood flow would provide an intestinal model more closely resembling normal human jejunum. Methods: Jejunal enteroid monolayers were studied in the Emulate, Inc Intestine-Chip under conditions of constant luminal and basolateral flow that was designed to mimic normal intestinal fluid flow, with human umbilical vein endothelial cells (HUVECs) on the basolateral surface and with Wnt3A, R-spondin, Noggin only on the luminal surface. Results: The jejunal enteroids formed monolayers that remained confluent for 6-8 days; began differentiating at least as early as day two post-plating, and demonstrated continuing differentiation over the entire time of the study as shown by quantitative real-time polymerase chain reaction and Western blotting. These results were consistent with continual differentiation, as was shown to occur in mouse villus enterocytes. Compared to differentiated enteroid monolayers grown on Transwell inserts, enteroids exposed to flow were more differentiated but exhibited increased apoptosis and reduced carbohydrate metabolism as shown by proteomic analysis. Conclusions: This study of human jejunal enteroids-on-chip suggests that luminal and basolateral flow produce a model of continual differentiation over time and NaCl absorption that mimics normal intestine and should provide new insights in intestinal physiology.