Levodopa associated homocysteine increase supports neuronal death

Increased plasma total homocysteine levels (t-Hcys) represent an independent single risk factor for atherosclerosis related disorders and appear in neurodegenerative diseases, i.e. Parkinson's disease (PD), Huntington's disease (HD), Alzheimer's disease (AD), or correlate to brain atrophy. Levodopa (LD) supports t-Hcys elevation, since LD is administered with dopa decarboxylase inhibitors to prevent its peripheral degradation. This increases conversion of levodopa to 3-O-methyldopa (3-OMD) by catechol-O-methyltransferase (COMT). COMT requires Mg2+ as cofactor and as methyl donor S-adenosylmethionine, which resul…