Primary Human Cell-Based 3D Colon Tissue Model for Toxicological Studies

The aim of this study was to reconstruct and characterize a primary cell based human 3D colon tissue model for the study of: 1) microbiome, 2) colorectal care product screening for their irritation potential, 3) safety and efficacy of anti-microbial products and colon-targeted drug candidates, and 4) inflammation. This study characterizes the structural features of a novel in vitro tissue model reconstructed from normal human primary colon epithelial cells (CEC) with or without fibroblasts. Primary cells were expanded in monolayer culture and seeded onto microporous membrane inserts to reconstruct 3D organotypic colon tissues. Tissues were characterized for polarity of epithelial cells (H&E staining), fibroblast cell markers (confocal microscopy), and barrier integrity (transepithelial electrical resistance, TEER). The colon model’s functionality for toxicological studies was tested using Indomethacin (0.01and 0.001%), Dextran sulfate sodium salt (DSS; 2.5%), and SN38 (20 μM) following acute basolateral exposure for 48 hr. Analysis of the 3D colon tissue model revealed: 1) wall-to-wall tissue growth, 2) epithelial cell morphology similar to human colon, 3) a physiological TEER value of >300 Ώ*cm2 mimicking the colon microenvironment, and 4) expression of CK19 (epithelial cell marker), and expression of vimentin (fibroblast cell marker), and 5) Alcian blue PAS staining (mucous producing goblet cell marker). Exposure to Dextran sulfate sodium salt (DSS, 2.5%) and SN38 (20uM) showed a 79% and a 40% decrease in TEER values, respectively, compared to untreated controls which indicates toxicity of the test articles. This novel human cell-based colon tissue model will be a useful tool for pre-clinical assessment of microbiomes, mucosal inflammation, and screening of colorectal care products for their irritation potential. Such models can also reduce the use of animals for experimentation.