title: Higher iron in the red nucleus marks Parkinson's dyskinesia.
abstract: Dopamine cell loss and increased iron in the substantia nigra (SN) characterize Parkinson's disease (PD), with cerebellar involvement increasingly recognized, particularly in motor compensation and levodopa-induced dyskinesia (LID) development. Because the red nucleus (RN) mediates cerebellar circuitry, we hypothesized that RN iron changes might reflect cerebellum-related compensation, and/or the intrinsic capacity for LID development. We acquired high resolution magnetic resonance images from 23 control and 38 PD subjects (12 with PD and history of LID [PD+DYS]) and 26 with PD and no history of LID (PD-DYS). Iron content was estimated from bilateral RN and SN transverse relaxation rates (R2*). PD subjects overall displayed higher R2* values in both the SN and RN. RN R2* values correlated with off-drug Unified Parkinson's Disease Rating Scale-motor scores, but not disease duration or drug dosage. RN R2* values were significantly higher in PD+DYS compared with control and PD-DYS subjects; control and PD-DYS subjects did not differ. The association of higher RN iron content with PD-related dyskinesia suggests increased iron content is involved in, or reflects, greater cerebellar compensatory capacity and thus increased likelihood of LID development.
authors.affiliation: Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA 17033-0850, USA.
authors.forename: Mechelle M
authors.initials: MM
authors.lastname: Lewis
authors.forename: Guangwei
authors.initials: G
authors.lastname: Du
authors.forename: Michal
authors.initials: M
authors.lastname: Kidacki
authors.forename: Nisargkumar
authors.initials: N
authors.lastname: Patel
authors.forename: Michele L
authors.initials: ML
authors.lastname: Shaffer
authors.forename: Richard B
authors.initials: RB
authors.lastname: Mailman
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000378:metabolism*; D012012:Red Nucleus / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D015415:Biomarkers; D007501:Iron