Development of an Improved Three-DimensionalIn VitroIntestinal Mucosa Model for Drug Absorption Evaluation

Abstract

Human epithelial cell culture models of monolayer Caco-2 cells have been widely employed to assess the absorption of drug molecules across intestinal mucosa. However, cautions should be taken when interpreting the conclusions from those models due to their undesirable phenotype and functionality when compared with the native intestinal tissue. In the present study, an improved, more physiologically relevant three-dimensional (3D) culture model of the intestinal mucosa was developed to study drug absorption, in which a coculture of epithelial cells, including Caco-2 cells and HT29-methotrexate cells, was indirectly seeded on a Transwell filter insert with collagen gel and stromal cells (fibroblasts and immunocytes) incorporation. This setting-up provided a compatible environment to improve the phenotype and functionality of the epithelial cells. Compared with the monolayer culture of Caco-2 cells, the reconstructed 3D model displayed more physiologically relevant characteristics evidenced by its decreased TEER value and mucus-like layer formation. A decreased expression of P-gp and an increased expression of BCRP were also observed in the current 3D culture model, leading to a changed secretory permeability of their substrates. More importantly, an improved correlation (R(2)=0.843) was obtained between the absorptive permeability across the 3D coculture model and the human absorption fraction especially for those model compounds with moderate or high permeability. Thus, this engineered 3D coculture model presents a unique, improved opportunity to evaluate drug permeability in vitro.

Life in 3D is never flat: 3D models to optimise drug delivery

“…Techniques that have been used to improve physiological relevance involve the coculture of cells with either fibroblast cells to imitate the intact intestine [131] or cells of the immune system to model inflammatory bowel disease [132]. While such cell culture techniques have improved upon traditional monocell culture, they do not fully recapitulate the actual geometry of intestinal tissue [123,127].…”

Oral uptake of nanoparticles: human relevance and the role of in vitro systems

“…Caco-2 cells in combination with methotrexate-treated HT-29 were seeded on collagen gels containing primary fibroblasts and differentiated THP-1 cells in order to mimic both the epithelial layer with goblet cells and the immune system (Li et al 2013). Other models combine Caco-2 cells with peripheral mononuclear cells and dendritic cells (Kleiveland 2015).…”

Towards the characterization of an in vitro triple co-culture intestine cell model for permeability studies

“…Aside from this, the most important feature is the production of mucus all over the monolayer similarly to the human intestinal mucosa (Behrens et al, 2001;Lesuffleur et al, 1990;Wikman et al, 1993;Mahler et al, 2009b). Moreover, the Caco-2:HT29-MTX co-culture model also resembles the small intestine in a closely way since the HT29-MTX cells do not form TJ as tight as in cultures with only Caco-2 cells (Pontier et al, 2001;Li et al, 2013).…”