Effects of entacapone on plasma homocysteine in Parkinson's disease patients on levodopa

Abstract

To explore the effects of entacapone on the plasma level of homocysteine (Hcy) in Parkinson's disease (PD) patients on levodopa. This cross-sectional study was made up of 4 groups, i.e. 'L + E' group (primary PD patients on levodopa and entacapone), 'L' group (primary PD patients on levodopa alone), 'L(-)' group (primary PD patients never on levodopa) and control group (people without PD or any other nervous system diseases). They were randomly selected from the PD patient database of our department in September 2012. At the beginning, 60 cases were selected for each group. The C677T genotypes of methylenetetrahydrofolate reductase (MTHFR) were identified and the plasma concentrations of Hcy, folic acid and vitamin B12 detected in each subject. Then group t test, single factor analysis of variance and χ(2) test were used for statistical analysis by SPSS 11.5 software. Among 240 early subjects, 98 cases with CC genotype at 677 site of MTHFR gene were finally recruited. Statistical analysis revealed no differences in age, gender, plasma concentrations of folic acid and vitamin B12 among the groups. The PD duration of 'L + E' group (96 ± 21 months) were the longest among 3 groups, followed by those of 'L' group (51 ± 17 months) and 'L(-)' group (21 ± 6 months). The treatment duration and daily dose of levodopa in 'L + E' group (77 ± 22 months, 765 ± 110 mg) were all higher than those in 'L' group (42 ± 14 months, 673 ± 73 mg). The plasma Hcy concentrations of 'L + E' group (15.1 ± 3.1 µmol/L) were lower than those of 'L' group (20.4 ± 4.7 µmol/L), but still higher than those of 'L(-)' group (12.2 ± 2.4 µmol/L) and control group (9.1 ± 2.2 µmol/L). The Hcy concentrations of 'L(-)' group were also higher than those of control group. Entacapone increases the bioavailability of levodopa and simultaneously alleviates partially its resulting hyperhomocysteinemia.