Serum hyaluronate in the assessment of liver endothelial cell function after orthotopic liver transplantation in the rat

Abstract

This study was designed to evaluate the use of serum hyaluronate as a marker of liver endothelial cell function after liver transplantation. We performed orthotopic liver transplantation in both isogeneic and allogeneic rejector models. After transplantation, hepatocyte function was assessed on the basis of serum ALT and total bilirubin levels, and liver endothelial cell function was judged on the basis of serum hyaluronate levels. Significant increase of hyaluronate in the rejector model, compared with the isogeneic model, was seen before any significant results could be obtained from conventional liver function tests. The impaired metabolism of hyaluronate in the rejector model was observed after intravenous injection of trace amounts of radioactive material. Serial studies demonstrate that the endothelial cell is a more susceptible target for the immune response than the hepatocyte. Serum hyaluronate concentration may be a better indicator in the early assessment of graft function. We also examined serum hyaluronate levels to evaluate cold ischemia-reperfusion injury to the liver endothelial cells in the isogeneic model. At 2 hr after reperfusion, hyaluronate levels in the 6-hr cold ischemia (nonviable allograft) group were significantly higher than in the 1-hr and 3-hr cold ischemia (viable allograft) groups. However, there was little difference between the viable allograft groups. After an intravenous injection of 1 mg/kg hyaluronate, the hyaluronate elimination rate in the 3-hr group was distinctly slower than that in the 1-hr group. These data indicate that the hyaluronate elimination rate may be a more sensitive marker of liver endothelial cell function in viable liver after a short period of ischemia. (Hepatology 1994;20:1323–1329).