Exposure of hepatic sinusoidal mononuclear cells to UW solution in situ but not ex vivo induces apoptosis

Background/Aims: We have previously reported that human hepatic sinosoidal mononuclear cells may have a higher sensitivity to induction of apoptosis than peripheral blood mononuclar cells. In this study, the effects of two different preservation solutions on the functions of those hepatic mononuclear cells were evaluated in living-related liver transplantation. Methods: Ten and 11 liver grafts were perfused via the portal vein with University of Wisconsin solutions (UW group) and Bretschneider's Histidine-Tryptophan-Ketoglutarate solutions (HTK group), respectively. Hepatic mononuclear cells were isolated from the effluent preservation solution passing through the graft livers. Cytofluorometry, cytotoxic assay, and DNA analysis were performed. Results: There were no significant differences in surface antigens and natural killer activity of hepatic sinusoidal mononuclear cells between the UW and HTK groups. At the time of isolation, the viability of hepatic sinusoidal mononuclear cells in both groups was more than 99%. In the UW group, the viability of hepatic sinusoidal mononuclear cells decreased to 30% through apoptosis in in vitro culture at 48 h after isolation. In the HTK group, however, their viability was maintained at more than 90% at 48 h in the same culture conditions, and additional exposure to UW solution ex vivo for 30 min did not induce apoptosis. Conclusion: Hepatic sinusoidal mononuclear cells isolated from the UW solution, not from the HTK solution, passing through the liver died through apoptosis, which was not induced by each component of the UW solution, but by exposure in situ .