A Gut-on-a-chip Model for Testing the Anti-inflammatory Effects of Active Compounds

Abstract

Animal models are gold standards for testing active compounds on intestinal inflammatory conditions. However, the high costs involved cannot justify their use in all circumstances, such as in food and nutrition research. This study aimed to develop a gut-on-a-chip in vitro platform for screening the effect of anti-inflammatory compounds on gut inflammation. Because of its micrometre size, the chip allowed for reduced consumption of reagents. Furthermore, the use of constant media perfusion recreates the biological cues naturally present in the human body. CFD simulations were first performed to determine the effect of flow rate and shear stress on intestinal Caco-2 cells. These conditions were then tested and validated in vitro on a single-chamber chip to establish cell monolayers featuring tight junctions and other proteins. Co-cultures of Caco-2 with classically activated M1 macrophages were established in a double-chamber chip to represent the interaction between epithelial and immune cells. It was also found that damages of the intestinal barrier in vitro could be recreated via inflammatory triggers with TNF-α+LPS. Furthermore, this gut-on-a-chip was paired with a highly sensitive gene expression analysis for screening of over two hundred genes involved in human inflammation. To validate the functionality of the system, Dexamethasone and Mesalazine were used to modulate inflammation in both Caco-2 and M1 cells co-cultured in the gut-on-a-chip. To complement the study, Australian propolis was adopted as a natural product with anti-inflammatory properties. Regulations of genes involved in inflammatory mechanisms such as MAP2K6, COX2 and TNF were also recorded, resembling in vivo conditions. The findings suggest that the model developed in this study is functional and cost-effective and given the lowered consumption of reagents, this gut-on-a-chip could be used not only in the nutraceutical industry but also for the screening of expensive pharmaceuticals.