Coupled In-Silico and In-Vitro Modelling of Hepatocyte Cell Aggregation as a Step Towards Improved Biomaterial Risk Assessment

Abstract

Introduction: The formation of spheroidal multicellular aggregates for hepatocytes has drawn attention as it has been shown to closely mimic the natural environment found in vivo [1]. Due to many factors that influence the formation of aggregates/spheroids,coupled in-silico and in-vitro modelling of hepatocyte cell aggregation is important in order to reduce the number of experiments and optimize the necessary conditions to form the aggregates/spheroids. Experimental methods: Differentiated human hepatocytes (HepaRG) and hepatic stellate cells (LX-2) have been used to form hepatic spheroids at a ratio of 4:1 similar to that of parenchymal:nonparenchymal cells in the liver tissue. Formation of the hepatic spheroids was achieved using 2 conventional methodologies i.e. low adherent coating surface to form spheroids and a high-density array of pyramid-shaped microwells,into which a suspension of single cells is centrifuged-AggreWell system. Numerical methods: Partial differential equations explain the early stages of the cell aggregation process,starting from the principles of mass and momentum balance for cells,culture medium,and ECM production [2]. Based on many input parameters including different material characteristics for the low adherent coating and cells etc.,the model predicts the cell volume fraction,velocity of the cells,and cell density as a function of time. Results and conclusions: Developed model is able to predict formation of aggregates and how different parameters affect the number of aggregates,as well as their speed of aggregation. Developed model can be used for experimental planning and is a step towards improved biomaterial risk assessment.