Significance of Hyaluronic Acid for Evaluation of Hepatic Endothelial Cell Damage after Cold Preservation/Reperfusion

Abstract

Serum hyaluronic acid (HA) levels during or after liver transplantation can reflect graft viability in animal models. Decreased HA clearance in nonviable grafts seems to reflect hepatic endothelial cell damage induced by cold preservation/reperfusion. Therefore, we examined the relationship between HA clearance and endothelial cell damage, using an isolated perfused rat liver (IPRL) model. The grafts were separated into four groups, according to cold preservation time: minimal storage (Control: n = 9), 4-hr preservation (n = 9), 5-hr preservation (n = 8), 6-hr preservation (n = 9). After cold storage, grafts were put on the recirculating IPRL system and then reperfused for 120 min with 37°C oxygenated Krebs-Henseleit buffer, containing HA and sodium taurocholate. To examine the function of sinusoidal endothelial cells and hepatocytes, serial measurements of HA, total bile acids, and conventional parameters in the perfusate were taken. After the perfusion, a trypan blue exclusion test was done to assess the microscopic sinusoidal lining cell (SLC) damage. HA clearance from the perfusate showed a preservation time-dependent decrease which clearly distinguished between 4- and 6-hr preserved grafts. Trypan blue uptake ratio of SLC increased in accordance with preservation time. HA clearance at 120 min after reperfusion showed a highly significant correlation with histologically assessed SLC damage. These results suggest that HA is useful to evaluate the extent of endothelial cell damage after cold storage and reperfusion. The significance of HA as a predictor of graft viability is also confirmed.