Ex Vivo Induction of mRNA in Human Whole Blood as a New Platform of Drug and Dietary Supplement Development

PURPOSE: We introduced a new concept of ex vivo gene expression analysis (Mitsuhashi, Clin Chem 53:148–149, 2007), where drug action was simulated under physiological conditions. This model system was applied to study various fields of drug development. MATERIALS AND METHODS: Heparinized human whole blood was incubated with drugs for less than 4h. The changes of specific mRNA were then quantified using the method we developed (Mitsuhashi, Tomozawa, Endo, and Shinagawa, Clin Chem 52:634–642, 2006). RESULTS: The mRNA quantitation method was used as a model system to study the following areas: (1) identification of respondents and non-respondents, (2) ex vivo compound screening, (3) determination of individually optimized doses, (4) drug-to-drug comparison, (5) assessment of leukocyte toxicity, (6) discovery of molecular targets, (7) assessment of the action of dietary supplements, and (8) characterization of respondents and non-respondents for various dietary supplements. CONCLUSION: Since ex vivo assays are safe, a large number of healthy donors and disease patients can be recruited to identify individual-to-individual variations, which is not available from current preclinical study models. Although each system should be validated using a large number of samples, the ex vivo analysis will be a new tool for the development of drugs and dietary supplements in future. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11095-007-9510-2) contains supplementary material, which is available to authorized users.