Gut-liver-axis microphysiological system for studying cellular fluidic shear stress and inter-tissue interaction

To clarify the physiological and pathological roles of gut-liver-axis (GLA) in the human body, a GLA microphysiological system (GLA-MPS) holds great potential. However, in current GLA-MPSs, the importance of a physiologically relevant flow for gut and liver cells' cultivation is not fully addressed. In addition, the integration of individual organ perfusion, circulation flow, and organ tissue functions in a single device has not been achieved. Here, we introduce a GLA-MPS by integrating two cell-culture chambers with individually applied perfusion flows and a circulation channel with an on-chip pneumatic micropump under cell-culture chambers via a porous membrane for interconnecting them. We analyzed the fluid shear stress (FSS) with computational fluid dynamics simulations and confirmed that the physiologically relevant FSS could be applied to the gut (Caco-2) (8 x 10(-3) dyn cm(-2)) and liver (HepG2) cells (1.2 x 10(-7) dyn cm(-2)). Under the physiologically relevant flow, the Caco-2 and HepG2 cells in the GLA-MPS maintained a cell survival rate of 95% and 92%, respectively. Furthermore, the expression of functional proteins such as zonula occludens 1 (in Caco-2) and albumin (in HepG2) was enhanced. To demonstrate the GLA interaction, the inflammatory bowel disease was recapitulated by applying lipopolysaccharide for only Caco-2 cells. The inflammatory proteins, such as inducible nitric oxide synthase, were induced in Caco-2 and HepG2 cells. The presented GLA-MPS can be adapted as an advanced in vitro model in various applications for disease modeling associated with inter-tissue interactions, such as inflammatory disease. Published under an exclusive license by AIP Publishing.

Automated summary

This study presents a gut-liver-axis microphysiological system (GLA-MPS) that integrates individual cell-culture chambers with perfusion flows and a circulation channel via a porous membrane. The system successfully applies physiologically relevant fluid shear stress to gut and liver cells, resulting in high cell survival rates and enhanced expression of functional proteins. The GLA-MPS also allows for the modeling of inflammatory bowel disease through the application of lipopolysaccharide. This advanced in vitro model has significant implications for studying the physiological and pathological roles of the gut-liver-axis and related disease modeling.