#1343 Microfluidic kidney tubuloids-on-a-chip for improved drug translation

Abstract Background and Aims Current 2D in vitro models of renal epithelium lack key features of the in vivo setting, such as tubular structure and perfusion, resulting in low translatability to human situations and failure in clinical translation. Advanced renal in vitro models are of great importance to study kidney function under healthy and diseased conditions. Kidney tubular epithelial organoids, called tubuloids, are three-dimensional multicellular structures that recapitulate tubular function and have been used to model genetic, metabolic, and infectious renal diseases. To increase physiological relevance of the tubuloids, they can be integrated into an organ-on-a-chip system. This microfluidic technique is becoming increasingly recognized as a valuable tool for adding physiologically relevant cues to traditional cell culture including long-term gradient stability, continuous perfusion, and interaction with other cell types such as vasculature. Method Here, we introduce the OrganoPlate microfluidic platform, which can accommodate up to 64 independent microfluidic chips in a microtiter plate format, allowing the growth of 64 independent kidney tubuloid-derived barrier tissues in the form of perfused tubules. To this end, tubuloids derived from adult kidney tissue were plated as single cells in the OrganoPlate against an extracellular matrix (ECM). These renal tubules can be formed in just four days of culture in the device showing rapid and reproducible cell polarization, tight junction formation, proper expression of renal markers and functional transport. Results When integrated into an OrganoPlate system, kidney tubuloids form leak-tight, perfusable tubes with stable Trans Epithelial Electrical Resistance (TEER) and are suitable for high-throughput screening of compound effects through assessment of barrier integrity by use of OrganoTEER and by real-time imaging of transport. OrganoPlate grown kidney tubes treated with Pgp inhibitor Verapamil show significant reduction of Rhodamine123 transport through kidney tubule barrier which confirms show stable activity of Pgp transporter and usability of the model in studying renal drug clearance. Conclusion Our results demonstrate the suitability of our in vitro microfluidic kidney tubuloid-on-a-chip model in mimicking key physiological aspects of the kidney and offer new ways for studying organ physiology and renal disease mechanisms, toxicity screening, and personalized medicine. Additionally, the use of animal models, as well as the costs of drug development, can be reduced.