Inclusion of Trehalose (TRH) into liposomes to regulate uptake of this cryoprotectant into human hepatocytes.

Purpose. Problems with the limited availability of human hepatocytes for cell transplantation may be overcome by improving the efficiency of their cryopreservation. TRH-loaded liposomes could enhance epatocyte viability by regulating the intracellular uptake of the cryoprotectant [1]. Methods. TRH-loaded liposomes were prepared by film hydration method (EPC, sodium cholate, 200mM TRH solution) [2]. Liposomal size was determined by dynamic light scattering. Intraliposomal TRH content was measured using the Megazyme spectrophotometric method. After incubation (1-5 h, 37°C, 5% CO2, 95% RH) of human hepatocytes with TRH-loaded liposomes or equivalent TRH solution, intracellular sugar content was determined. Cell viability was evaluated by trypan blue exclusion. Results. Size analysis (320.2 nm diameter) and distribution (93.40.4%) suggested formation of highly homogeneous, reproducible Small Unilamellar Vesicles (SUVs). Encapsulation efficiency was 332% w/w. After incubation of hepatocytes with loaded liposomes, intracellular TRH content was about 0.1 mg/million of cells and the cell viability (858%) was unvarying and comparable to the control. By contrast, after incubation with TRH solution, hepatocyte viability dropped to 485%. Conclusions. TRH-loaded SUVs seem a useful tool in controlling intracellular uptake of the cryoprotectant. [1] Katenz E. et al., Liver Tranplantation 45 (2007) 13-38.[2] Chiantia S. et al., Langmuir 21 (2005) 4108-4116.