InTESTine on-a-chip: Towards a more physiological and predictive human intestinal barrier model
Abstract: A majority of the screening and predictive models do not reflect properly the physiological situation of the human intestinal tract resulting in low translational value to the clinical situation. Therefore, highly realistic models resembling the human in vivo situation are needed, for instance ex vivo models. We have successfully applied human intestinal tissue into the InTESTineTM two-compartmental model. This set-up is suitable to study drug absorption, intestinal wall metabolism, endocrine responses and mucus interactions. With human intestinal tissue we demonstrated the intestinal wall metabolism of testosterone (CYP3A4) by showing a linear formation (R2=0.997) of the main metabolites androstenedione and 6B-hydroxytestosterone, indicating no loss of metabolic capacity. Besides these read-outs, the system is very suitable to study the paracellular as well as the transcellular transport in the human intestinal tissue.
In order to extend the viability of the tissue, which is needed to study chronic drug exposure effects, we applied a luminal and basolateral flow using a microfluidic device. An increase in the viability and functionality of control intestinal tissue, up to 24h of incubation, was demonstrated by a low LDH leakage while maintaining a high intracellular LDH (90%) and retaining barrier integrity (<0.5% FD4 leakage/h) under control conditions. Transport and metabolic functionality of the tissue was maintained during the 24 hours incubation. Also upon stimulating the tissue with Flagellin as a known pro-inflammatory stimulus, a high increase in IL-8 secretion was shown compared to blanc and static controls. Currently, we are investigating the co-culture with anaerobic apical microbiota conditions. In conclusion, we can successfully use human intestinal tissue for short and longer-term incubations, which can be applied as a reliable tool for the assessment of processes that determine human intestinal permeability as well as (anaerobic) host-microbe-immune responses when mounted in the microfluidic device.