Plasma homocysteine and MTHFR C677T genotype in levodopa-treated patients with PD

Abstract

Plasma homocysteine and cysteine levels were measured in 90 patients with PD with the MTHFR C677T (T/T) genotype. The authors found that the levels of homocysteine-a possible risk factor for vascular disease-were elevated by 60% in levodopa-treated patients with PD, with the most marked elevation occurring in patients with the T/T genotype. Cysteine levels in subjects with PD did not differ from levels in control subjects. In the T/T genotype patients, homocysteine and folate levels were inversely correlated. Increased homocysteine might be related to levodopa, MTHFR genotype, and folate in PD.

Idiopathic Parkinson's Disease, Vascular Risk Factors and Cognition: A Critical Review

“…Sixteen articles were rejected because: 5 were only abstracts (Antonini et al, 2006;Litvinenko et al, 2005;Menendez et al, 2007;Shin & Sohn, 2006;Stathis et al, 2006), 6 didn't report the results of the cognitive assessment or didn't assess cognition using at least one standardized cognitive measure (Blandini et al, 2001;Ebmeier et al, 1990;Kuhn et al, 1998;Muller et al, 1999;Nakaso et al, 2006;Yasui et al, 2000;) and 5 didn't assess the effects of vascular risk factors (Aarsland et al, 2004;de Lau et al, 2005;Hughes et al, 1992;Locascio et al, 2003;Papapetropoulos et al, 2006). Table 1 summarizes the study design and participant's characteristics in the 18 selected studies.…”

“…Some studies also support a genetic role in Hcy in PD: blood plasma levels are elevated in levodopa-treated patients homozygous for the MTHFR C667T mutation Todorovic et al, 2006;Yasui et al, 2000). Hcy has also been involved in multiple biological mechanisms and notably as a neurotoxin contributing to neurodegeneration.…”

“…Hence, these results may support a possible vascular contribution to cognitive impairment by Hcy. As mentioned in section 3.4.1, L-dopa intake in PD patients induces increased levels of Hcy (Kuhn et al, 1998;Müller et al, 1999;Rogers et al, 2003;Yasui et al, 2000) because L-dopa breakdown interferes with Hcy metabolism. Since Hcy also has been associated with hypertrophy of the intima-media complex of the carotid artery, a marker of atherosclerotic disease (Megnien et al, 1998), Ldopa-induced Hcy may promote systemic atherosclerosis processes, thus compromising vascular health.…”

“…Levodopa (L-dopa) intake in PD was associated with Hcy blood and plasma levels (Kuhn et al, 1998;Müller et al, 1999;Rogers et al, 2003;Yasui et al, 2000). Levodopa is a substrate for S-adenosyl methionine (SAM)-dependent methylation.…”

Investigation of Methyl Tetrahydro-Folate Reductase C677t Polymorphism in a Sample of Patients in a Hospital Based Diagnostic Setting in Sri Lanka

“…Among the nutritional factors, deficiencies of vitamins B6, B12, and folate are associated with elevated plasma homocysteine concentrations. Supplementation with folic acid alone and in combination with vitamins B6 and B12 reduces the plasma homocysteine concentration (Yasui et al, 2000). The meta-analysis of the size of reduction of homocysteine concentration achieved by different doses of folic acid with or without vitamin B 12 and B6 in clinical trials.…”