Abstract
Introduction Gastrointestinal (GI) in vitro models have received lasting attention as an effective tool to model drug and nutrient absorption, study GI diseases, and design new drug delivery vehicles. A complete model of the GI epithelium should at a minimum include the two key functional components of the GI tract: mucus and the underlying epithelium. Mucus plays a key role in protecting and lubricating the GI tract, poses a significant barrier to orally administered therapies and pathogens, and serves as the microbiome niche microenvironment. These functions are reliant on the biophysical material properties of the mucus produced, including viscosity and pore size.
Methods In this study, we generated in vitro models containing Caco-2 enterocyte-like cells and HT29-MTX goblet-like cells and determined the effects of coculture and mucus layer on epithelial permeability and biophysical properties of mucus using multiple particle tracking (MPT).
Results We found that mucus height increased as the amount of HT29-MTX goblet-like cells increased. Additionally, we found that increasing the amount of HT29-MTX goblet-like cells within culture corresponded to an increase in mucus pore size and mucus microviscosity, measured using MPT. When compared to ex vivo mucus samples from mice and pigs, we found that an 80:20 ratio of Caco-2:HT29-MTX coculture displayed similar mucus pore size, microviscosity, and elastic modulus to those of porcine ileum.
Conclusions These coculture models could be valuable tools in simulating the mucus barrier and mucus microenvironment and can be utilized for a variety of applications including the study of GI diseases, food absorption, or therapeutic development.
Competing Interest Statement
The authors have declared no competing interest.
