Basal and post-methionine serum homocysteine and lipoprotein abnormalitiesin patients with chronic liver disease

Background: Lipoprotein abnormalities are commonly found in chronic liver d iseases (CLDs), particularly hypercholesterolemia in primary biliary cirrho sis (PBC), However, affected patients may not be at increased risk of coron ary heart disease, Cirrhotic patients display impaired methionine clearance , and an increased level of homocysteine, a methionine metabolite, is an in dependent risk factor for coronary heart disease, Thus, we hypothesized tha t the low risk of coronary heart disease in patients with CLD may be relate d to low serum levels of homocysteine. The aim of this study was to test th is hypothesis after methionine load and to describe the serum lipoprotein p rofile in patients with PBC and in patients with hepatocellular liver disea se, Methods: Fifteen female patients (mean age, 58.2 +/- 11.7 years) with PBC, 15 female patients (mean age, 54.5 +/- 9.6 years) with other causes of CLD, and 15 healthy sex- and age-matched controls were given L-methionine (50 m g/kg of ideal body weight), Basal fasting serum homocysteine level and 2, 4 , and 6 hours of post-methionine load were determined using high-performanc e liquid chromatography with a fluorometric detector, Levels of fasting ser um cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), lipoprotein (a) (Lp(a)), and apoprotein B were also dete rmined, Results: Results showed that mean basal and post-methionine load (6 hours) serum homocysteine levels were statistically significantly higher in the pa tients with PBC and with CLD than in the control group (P=0.04) and that le vels of serum cholesterol, LDL, HDL, and apoprotein B were significantly hi gher in the PBC patients than in the other two groups (P less than or equal to0.05). There was no correlation between any of these parameters and the severity of liver disease, Serum HDL was significantly lower in the CLD gro up (P less than or equal to0.05) and correlated with severity of liver dise ase, There was no significant difference in serum cholesterol, LDL, or apop rotein B between the CLD group and the controls, Serum triglyceride and Lp( a) levels were similar for all three groups, Conclusions: In contrast to previous reports, the site of the methionine me tabolic impairment,vas found to be below the homocysteine synthesis level, For most patients with CLD, factors other than serum homocysteine or Lp(a) are respon sible for the reduction in the risk of coronary heart disease, F urther studies with larger samples are needed.