title: Lower levels of uric acid and striatal dopamine in non-tremor dominant Parkinson's disease subtype.
abstract: Parkinson's disease (PD) patients who present with tremor and maintain a predominance of tremor have a better prognosis. Similarly, PD patients with high levels of uric acid (UA), a natural neuroprotectant, have also a better disease course. Our aim was to investigate whether PD motor subtypes differ in their levels of UA, and if these differences correlate with the degree of dopamine transporter (DAT) availability. We included 75 PD patients from whom we collected information about their motor symptoms, DAT imaging and UA concentration levels. Based on the predominance of their motor symptoms, patients were classified into postural instability and gait disorder (PIGD, n = 36), intermediate (I, n = 22), and tremor-dominant (TD, n = 17) subtypes. The levels of UA and striatal DAT were compared across subtypes and the correlation between these two measures was also explored. We found that PIGD patients had lower levels of UA (3.7 vs 4.5 vs 5.3 mg/dL; P<0.001) and striatal DAT than patients with an intermediate or TD phenotype. Furthermore, UA levels significantly correlated with the levels of striatal DAT. We also observed that some PIGD (25%) and I (45%) patients had a predominance of tremor at disease onset. We speculate that UA might be involved in the maintenance of the less damaging TD phenotype and thus also in the conversion from TD to PIGD. Low levels of this natural antioxidant could lead to a major neuronal damage and therefore influence the conversion to a more severe motor phenotype.
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Ismael
authors.initials: I
authors.lastname: Huertas
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Jesús
authors.affiliation: Servicio de Medicina Nuclear. UDIM. Hospital Universitario Virgen del Rocío, Seville, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Lojo
authors.affiliation: Servicio de Medicina Nuclear. UDIM. Hospital Universitario Virgen del Rocío, Seville, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: García-Gómez
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Cáceres-Redondo
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Oropesa-Ruiz
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Fátima
authors.initials: F
authors.lastname: Carrillo
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Vargas-Gonzalez
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Martín Rodríguez
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Gómez-Garre
authors.affiliation: Servicio de Medicina Nuclear. UDIM. Hospital Universitario Virgen del Rocío, Seville, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: García-Solís
authors.affiliation: Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Mir
mesh_terms: D000328:Adult; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D005684:Gait / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000097:blood* / Q000000981:diagnostic imaging / Q000503:physiopathology; D004856:Postural Balance / Q000235:genetics / Q000502:physiology; D014527:Uric Acid / Q000097:blood*
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D014527:Uric Acid; D004298:Dopamine