Hosted by: The SOT Risk Assessment and In Vitro and Alternative Methods Sections
The respiratory epithelium acts as a barrier between inhaled toxins and underlying tissue. Toxicant exposure often disrupts this barrier, leading to tissue imbalance, increased infection risk, and airway diseases. Transepithelial electrical resistance (TEER) is a common method to assess epithelial barrier integrity. However, inter-laboratory differences in methodology, equipment, and reporting hinder reproducibility and comparability of TEER data, limiting its reliability for toxicology research and regulatory decisions. Biological variability from human donor-derived primary cells adds further complexity. We evaluated the impact of technical variables on TEER measurements, focusing on equipment and washing solutions. TEER data varied significantly across electrode and insert manufacturers. Additionally, washing with 0.9% saline reduced epithelial integrity compared to unwashed controls. For positive controls, we identified two non-cytotoxic methods for reducing TEER without inducing cytotoxicity, demonstrating applicability across cultures from different respiratory regions. Our findings highlight the importance of standardizing TEER assay methodologies and reporting practices. This is essential for improving reproducibility, data interpretation, and the acceptance of in vitro systems as alternatives to animal testing in chemical safety evaluation. Thorough characterization of in vitro methods ensures their relevance, rigor, and reliability for decision-making.
Speaker: Erin A. Huber, PhD, RTI International