LIPOPROTEIN-X IN PATIENTS WITH CIRRHOSIS - ITS RELATIONSHIP TO CHOLESTASIS AND HYPERCHOLESTEROLEMIA

Lipoprotein-X (Lp-X) is an abnormal low-density lipoprotein frequently found in liver disease. It is regarded as the most sensitive and spec ific biochemical parameter for the diagnosis of intra- and extrahepati c cholestasis, Moreover, Lp-X is supposed to contribute to the develop ment of hypercholesterolemia in cholestatic liver disease, because it fails to inhibit ne novo cholesterol synthesis. This investigation Wil l focus on the relationship between the presence of Lp-X and serum lip id concentrations in cirrhosis, The significance of Lp-X in the diagno sis of cholestasis, compared with alkaline phosphatase (AP), gamma-glu tamyl transferase (GGT), and bilirubin levels, will be assessed as wel l. The present cross-sectional study includes 212 patients with histop athologically proven cirrhosis. The detection of Lp-X and the quantifi cation of alpha-, beta-, and pre-beta-cholesterol was based on agar ge l electrophoresis and polyanion precipitation. For the characterizatio n of liver function, the concentrations of albumin and bilirubin, the activities of liver enzymes, and coagulation times were assessed. In a subgroup of 40 individuals, liver biopsies were re-evaluated to confi rm or exclude intrahepatic cholestasis, As a result, there was no asso ciation between the appearance of Lp-X and total cholesterol concentra tions. While all patients with Lp-X showed intrahepatic cholestasis (p redictive value of the positive test = 1), only 16 of 28 patients with cholestasis formed Lp-X (sensitivity = 0.57). The activities of AP an d of GGT, as well as the concentrations of bilirubin, were strongly el evated in most patients, with and without cholestasis. The predictive values of AP, GGT, and bilirubin were 0.77, 0.69, and 0.74 for the pos itive test and 0.5, 0, and 0.6 for the negative test, respectively. We conclude that Lp-X is not related to hypercholesterolemia in cirrhosi s, The positive, but not the negative, Lp-X test has high predictive v alue for the diagnosis of cholestasis in cirrhosis, The biochemical pa rameters traditionally used for the assessment of extrahepatic cholest asis, AP, GGT, and bilirubin, do not support the diagnosis of intrahep atic cholestasis caused by cirrhosis.