The effect of human organ preservation and albumin flush solution on in vitro cell metabolic activity

In liver transplantation, the organ during the recipient's operation is traditionally flushed with 4.5% of human albumin solution to wash away the potassium-rich University of Wisconsin (UW) solution. It has been argued whether albumin could be useful at this stage. We used a new simple non-toxic assay to determine cell viability in vitro. Alamar Blue incorporates a redox indicator which changes colour from blue (oxidised form) to magenta (reduced form) in response to metabolic activity. Cultured human hepatocyte and HUVEC cell lines were exposed for 3, 6, 12 or 24 hours to plain medium, UW solution, human albumin 4.5% solution, UW-containing effluents before and after preservation as well as albumin flushes from different transplantation cases. After addition of Alamar Blue the optical density was measured at 570 nm and the background measured at 600 nm was subtracted. The studies showed a significantly lower metabolic rate of the cells exposed to albumin and albumin-containing flushes at all time periods, even after a short exposure such as 3 hours (p < 0.001). On the other hand, there was no significant difference of growth and metabolic activity rate between cells exposed to UW solution, different UW-containing flushes and medium for up to 12 hours. In conclusion, human albumin is a very poor solution for cell maintenance. In contrast, UW solution has comparable results with the full growth medium for up to 12 hours of exposure.