A cocktail of metabolic probes demonstrates the relevance of primary human hepatocyte cultures in a microfluidic biochip for pharmaceutical drug screening

In this paper, we compare the biotransformation capacities of cryopreserved primary human hepatocytes cultivated in a liver microfluidic biochip and in plates. The hepatocytes were exposed to the CIME cocktail (Carte d'Identite MEtabolique), a mixture of seven probes (acetaminophen, amodiaquine, caffeine, dextromethorphan, midazolam, omeprazole and tolbutamide) for key enzymes involved in the xenobiotic metabolism and pharmacokinetics. The purpose of the cocktail was to give an overview of the metabolic profile of the hepatocytes due to concomitant exposure and a simultaneous mass spectrometric detection method of the metabolites. The results showed a greater activity for CYP1A2, CYP2C9, CYP2C19 CYP2D6, CYP3A and UGT1A1 after 4 h of incubation in the microfluidic biochip when compared to the plate cultures. Furthermore, the metabolic ratio time-course measured at 1 h, 3 h and 4 h indicated that the enzymatic activity increased when the hepatocytes were cultivated in the microfluidic biochip, in contrast with their response in the plate cultures. These results illustrated the functional relevance of liver culture in the PDMS microfluidic biochip. The original method based on a microfluidic culture coupled with CIME cocktail analysis allowed the maintenance and the evaluation of the metabolic performances of the primary human hepatocytes through a new rapid assay. This metabolic analysis can thus become the reference situation when parallel studies of drug metabolism and toxicities are planned with functional hepatocytes in biochips. (C) 2011 Elsevier B.V. All rights reserved.