Development and Characterization of a Human Liver Spheroid Culture for Drug Metabolism and Disposition Studies

Abstract

The liver is the main organ of the human body involved in metabolism of xenobiotics. When developing drugs, it is important to have a model that predicts the metabolism and disposition of substances in the liver to be able to ensure the efficacy and safety of the drugs. In this thesis, a hepatic spheroid model is further developed and evaluated regarding the metabolic functions and genetic expression of the spheroids. The study aims at characterizing the spheroids regarding the gene expression and the activity of specific cytochrome P450 enzymes and over a time period of three weeks. Spheroids were made by culturing different cell types on ultra-low affinity plates on which cells self-assemble and form spheroids. The cell types evaluated for spheroid formation were: HepaRG cells, a co-culture of HepaRG and primary human stellate cells, primary human hepatocytes, and HepatoCells. HepaRG and co-cultured spheroids of HepaRG and primary human stellate cells were stable in culture for the cultivation period of three weeks. HepaRG spheroids showed results of metabolic activity and gene expression which make them suitable to be used for metabolism and disposition studies. Spheroids of HepatoCells were not stable for three weeks, as they disintegrated after two weeks. HepatoCell spheroids also did not show metabolic activity neither gene expression for any of the enzymes investigated in this study. Primary human hepatocytes did not form spheroids in the scope of this study, hence no evaluation was made. Conclusively, this study has shown the possibility to culture human hepatic spheroids formed from HepaRG cells, applicable for metabolism and disposition studies.