(193r) Influence of Hepatic Function Due to Co-Culturing with Endothelial Cell from Different Tissue Origins

Development of in vitro environments capable of mimicking physiological function has long been an aspiration of tissue engineers. The use of liver mimicking environments would be extremely beneficial in evaluating drug safety and efficacy, increasing the efficiency of the drug development process. In an effort to mimic in vivo architecture, three dimensional (3D) structures including cell aggregates and porous scaffolds have been investigated and reportedly exhibit more organitypic behavior. Also, the introduction of other cell types native to the organ of interest presents another way to mimic the physiological environment. We wanted to evaluate the effect of 2D and 3D, monoculture and co-cultures to determine which combination resulted in more closely mimicking in vivo behavior. We initially investigated the effect of culturing hepatocytes in 2D versus 3D on hepatic function by evaluating protein secretion, enzyme activity, cell viability, and metabolic profiles. Evaluation of enzymatic activity and metabolic profiles required challenging of cell cultures with a drug/substrate. We chose acetaminophen, due to readily available clinical data in literature. Metabolic profiles of the percentage of APAP consumption and the produced concentration of APAP metabolites (APAP-sulfate and APAP-glucuronide) were compared. The distribution of cells in the porous scaffold was also examined to ensure the culture environment was truly in 3D. Two hepatocyte cell lines, HepG2 and HepaRG, were investigated to determine the effect of cell line on function. We next investigated the addition of endothelial cells to hepatocyte cultures (2D and 3D) to determine the effect of co-culture on hepatic function using the same analysis techniques. Two endothelial cell lines, human umbilical vein (HUVEC) and liver sinusoidal (LSEC), were explored to determine effect on hepatocyte function. Protein secretion was higher in 2D compared with 3D in monocultures. The addition of endothelial cells closed the gap between protein secretion observed in monocultures. Co-cultures led to increased protein secretion in 2D and 3D compared with monocultures. Enzyme activity increased in 2D co-cultures compared with 2D monocultures. Metabolic profiles showed increased function in co-culture environments compared with monocultures.