title: Elevated plasma homocysteine levels in L-dopa-treated Parkinson's disease patients with dyskinesias.
abstract: BACKGROUND
  Elevated plasma homocysteine (Hcy) concentrations are associated with increased risk of systemic vascular diseases, Alzheimer's disease and vascular dementia. Several cross-sectional reports and two prospective clinical studies have recently reported elevated plasma Hcy levels in L-dopa-treated Parkinson's disease (PD) patients and Hcy has been proposed as a possible mediator for the development of long-term L-dopa motor complications (such as wearing off and on-off phenomena, and dyskinesias). The aim of the study was to elucidate a possible role of L-dopa-related hyperhomocysteinemia in the development of dyskinesias.
  
  
  METHODS
  In this cross-sectional study we compared Hcy, B(12) and folate levels in 53 PD patients treated with L-dopa (29 with dyskinesias, 24 without dyskinesias).
  
  
  RESULTS
  Mean plasma Hcy levels were higher in the group of PD patients with dyskinesias (19 vs. 15.4 micromol/L; T: 2.12; p=0.04). After taking into account potential confounding factors, analysis of the data revealed that the occurrence of dyskinesias progressively increased with plasma Hcy levels (relative risk 1.2, 95% CI 1.015-1.4; p=0.03).
  
  
  CONCLUSIONS
  Our results raise the possibility that Hcy plays a role in the development of dyskinesias, through its toxic effects on both dopaminergic neurons and non-substantia nigra, non-dopaminergic neurons.
authors.affiliation: Department of Neurological Sciences, University of Bari, Bari, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Zoccolella
authors.forename: Paolo
authors.initials: P
authors.lastname: Lamberti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Iliceto
authors.forename: Claudia
authors.initials: C
authors.lastname: Dell'Aquila
authors.forename: Cosimo
authors.initials: C
authors.lastname: Diroma
authors.forename: Angela
authors.initials: A
authors.lastname: Fraddosio
authors.forename: Simona V
authors.initials: SV
authors.lastname: Lamberti
authors.forename: Elio
authors.initials: E
authors.lastname: Armenise
authors.forename: Giovanni
authors.initials: G
authors.lastname: Defazio
authors.forename: Michele
authors.initials: M
authors.lastname: de Mari
authors.forename: Paolo
authors.initials: P
authors.lastname: Livrea
mesh_terms: D003430:Cross-Sectional Studies; D020820:Dyskinesias / Q000097:blood* / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood* / Q000150:complications / Q000188:drug therapy*
chemical_list: D006710:Homocysteine; D007980:Levodopa