Developing Toxicity and Pharmacokinetic Models for an in vitro Integrated Organ Platform (HuDMOP™)

March 24, 2020

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Authors: AY Efremenko2, N Hibbard1,  CE Hack2, P Mallick2, JA Willoughby Sr.1, M Andersen2 and JM McKim, Jr.1

Affiliations: 1IONTOX LLC, Kalamazoo, MI 49008, 2ScitoVation, Research Triangle Park, NC 27713

In vitro methods capable of describing systemic effects of chemicals require use of multiple tissue types connected with a common perfusate.  This arrangement allows integration of absorption, metabolism and toxicity data over extended times in vitro and provides a novel, animal-free tool for chemical, cosmetic, and pharmaceutical testing. In order to test this, a study on  the uptake and distribution of acetaminophen (APAP) in a human dynamic multi-organ plate  (HuDMOP™) with three tissue surrogates arranged in series:  first absorption across a human 3D intestine (EpiIntestinal, Mattek Corp), then on to a liver surrogate with human primary hepatocytes in sandwich culture and then to a kidney preparation (human renal proximal tubule cells) was developed. A common perfusate with human albumin connected the three compartments.   APAP was placed on the apical side of the intestinal surrogate at 0 and 24 hr.  Samples were collected from all three compartments over time and analyzed for APAP by LC/MS/MS and cytotoxicity by LDH leakage.  The APAP   in the uptake reservoir peaked to 60.7µM at around 4 hours with a total uptake of 72% of the applied dose entering the first reservoir. A simple PK model was developed to describe the three cellular platforms and their physical arrangement.  Mass balance equations were fit to experimental data to estimate uptake and transport characteristics. The inter-chamber flow rates and fitted experimental absorption rate constant, 0.79/hr, were consistent with a Cmaxof 62.0 µM and time of maximum concentration between 3 and 4 hr in the intestine compartment. With the current platform flow rates, much lower concentrations were present in the subsequent two compartments (liver and kidney) with maximum observed concentrations of 4.5 and 2.5 versus 3.1 and 0.9 uM predicted. The interplay between platform modeling and model-directed technical improvements will make the HuDMOPÔ results more directly applicable to expected in-life behavior of various chemicals.