Multi-organ-on-plate system for in-vitro studies of intestinal drug absorption and hepatotoxicity

More meaningful in-vitro models which simulate the physiological conditions of native tissue are becoming essential in the pharmaceutical field, for early and rapid screening of drug candidates. Here, we describe a multi-organ-on-plate system based on single and double flow mini bioreactor modules for dynamic in-vitro studies of intestinal drug absorption, drug metabolism and more relevant toxicity studies. The double flow module for membrane culture was firstly characterized using computational fluid dynamic models and measurements of pressure gradients, in order to indentify the optimal flow rates for maximizing the passage of solutes through the membrane. Then, cell culture experiments were performed with fully differentiated Caco-2 cells seeded on the semi-permeable membrane as a dynamic model of the intestinal epithelium, connected to a single flow chamber with metabolically competent human upcyte® hepatocytes (Medicyte GmbH, Germany) seeded on a 3D collagen cryogel. First we assessed the role of flow in modulating the passage of compounds across the epithelial barrier. Then toxicity tests were performed by administering different concentrations of hepatotoxic compounds (i.e. Diclofenac, Nimesulide, industrial nanoparticles) in the apical compartment of the MB, compared the data with cell cultures in transwells. Our results show: i) the presence of flow significantly increases translocation of all molecules tested across the membrane, ii) flow conditioned Caco-2 cells are more permeable to small hydrophilic compounds, despite having high TEER values iii) although they display higher levels of phenotypic markers (tight junctions, albumin expression etc), cells in the system are more susceptible to drug induced toxicity. In conclusion, the multi-organ-on-plate system predicts drug adsorption and toxicity better than traditional cell cultures and could be used to reduce, refine and eventually replace animal tests.