The Use of Human 3D Reconstructed Airway Cultures for Tobacco Product Evaluation: Precision Low-Volume Exposures at the Apical Site

Abstract

Abstract

With a mandate to evaluate the dynamics of pulmonary exposure to inhaled materials such as tobacco-based products, researchers are employing complex, human, three-dimensional pulmonary models. Human reconstructed airway (RHuA) tissues present a platform that more closely resembles airways in vivo. Grown at the air–liquid interface (ALI), RHuA tissues offer apical and basal compartments that allow flexibility in modeling physiologically relevant exposures and provide sampling location-specific results. Various instruments can produce smoke/aerosols (including that from e-cigarette) and expose tissues at the apical surface, but the quantitation of materials deposited remains a challenge. Alternatively, a solution containing solubilized materials can be applied through a pipette, but this less physiologically relevant method may adversely impact the tissue. We have tested the HP D300 digital dispenser as a means to deliver patterned picoliter amounts of dimethyl sulfoxide-based material (including total particulate matter) onto Epithelix MucilAir™ tissues. Release markers, viability assessment, and ciliary beat frequency (CBF) were compared in both the apical and basolateral compartments after 72 hours of exposure. Results of this work demonstrated pattern and volume dispensing accuracy. With the exception of CBF, no significant adverse effect from up to 707 nL total single dispense volume was detected using release marker or viability assays. This novel technology has demonstrated promising results as a method by which precise amounts of solubilized materials (e.g., tobacco-based extracts) may be delivered onto the apical surface of tissue grown at the ALI.