Abstract
The development of in vitro artificial small intestines that realistically mimic in vivo systems will enable vast improvement of our understanding of the human gut and its impact on human health. Synthetic in vitro models can control specific parameters, including (but not limited to) cell types, fluid flow, nutrient profiles and gaseous exchange. They are also “open” systems, enabling access to chemical and physiological information. In this work, we demonstrate the importance of gut surface topography and fluid flow dynamics which are shown to impact epithelial cell growth, proliferation and intestinal cell function. We have constructed a small intestinal bioreactor using 3-D printing and polymeric scaffolds that mimic the 3-D topography of the intestine and its fluid flow. Our results indicate that TEER measurements, which are typically high in static 2-D Transwell apparatuses, is lower in the presence of liquid sheer and 3-D topography compared to a flat scaffold and static conditions. There was also increased cell proliferation and discovered localized regions of elevated apoptosis, specifically at the tips of the villi, where there is highest sheer. Similarly, glucose was actively transported (as opposed to passive) and at higher rates under flow.
Highlights
Immortal intestinal epithelial cell lines such as Caco-2 are useful for in vitro studies of intestinal function, as they have ability to form polarized monolayers on membranes that separate the apical and basolateral space
We have previously shown that recreating the topography of the small intestine with biocompatible collagen or poly-lactic-glycolic acid (PLGA) scaffolds populated with accurately sized villi can lead to improved differentiation and paracellular permeability of Caco-2 monolayers along the villus axis[4,5,6]
To replicate the topography of the intestine, we constructed porous villous scaffolds via micromolding as described previously, we substituted our previous material (PLGA) with poly-ethylene-co-vinyl-acetate (PEVA) as it is not biodegradable, and is likely to be more resistant to erosion by shear
Summary
Immortal intestinal epithelial cell lines such as Caco-2 are useful for in vitro studies of intestinal function, as they have ability to form polarized monolayers on membranes that separate the apical and basolateral space. Kim et al.[20] created a “gut on chip” device that enabled the co-culture of Caco-2 cells and Lactobacillus rhamnosus on a porous membrane, with fluid flow channels for sustained cell culture, and cyclic strain for mimicking peristaltic motions They found that cyclic strain caused an increase in Caco-2 elongation, Transepithelial electrical resistance (TEER), differentiation and paracellular permeability. What is missing is a device that provides both the accurately-sized villus topography and fluid flow to improve study of intestinal absorption, drug delivery, and intestinal barrier function Towards this aim, we developed a 3-D printed bioreactor that can both contain villus scaffolds and create separation of the apical and basolateral spaces in a manner in which fluid flow exposes intestinal epithelial cells to physiologically relevant shear stresses
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call