title: Lymphocyte vitamin C levels as potential biomarker for progression of Parkinson's disease.
abstract: OBJECTIVE
  Vitamin C is a major antioxidant and also is known as a neuromodulator in dopaminergic neurons. The aim of this study was to investigate the association between lymphocyte and plasma vitamin C levels in various stages of Parkinson's disease (PD).
  
  
  METHODS
  Sixty-two individuals with PD (age 71 ± 8.8 y [mean ± SD]) being treated at Shizuoka General Hospital from December 2007 to August 2013 were consecutively recruited. PD severity was classified using the Hoehn-Yahr scale for staging PD. Fasting blood samples were collected, and plasma and lymphocyte vitamin C levels were measured. The association between PD severity and vitamin C levels was estimated by ordinal logistic regression with confounding variables.
  
  
  RESULTS
  The distribution of Hoehn-Yahr stages in patients was as follows: stage I, 7; II, 28; III, 16; and IV, 11. Lymphocyte vitamin C levels in patients with severe PD were significantly lower (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.80-0.97; P < 0.01) compared with those at less severe stages. Plasma vitamin C levels also tended to be lower in patients with severe PD; however, this was not significant (OR, 0.98; 95% CI, 0.96-1.00; P = 0.09).
  
  
  CONCLUSIONS
  Our findings suggest that lymphocyte vitamin C levels in the peripheral blood may be a potentially useful biomarker for the progression of PD.
authors.affiliation: Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Ide
authors.affiliation: Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan; Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan. Electronic address: hyamada@u-shizuoka-ken.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.affiliation: National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Keizo
authors.initials: K
authors.lastname: Umegaki
authors.affiliation: Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Katsuki
authors.initials: K
authors.lastname: Mizuno
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Kawakami
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Kang
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Clinical Laboratory Medicine, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Shiosaki
authors.affiliation: Department of Clinical Laboratory Medicine, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Tsunehiro
authors.initials: T
authors.lastname: Yokochi
authors.affiliation: Department of Neurology, Shizuoka General Hospital, Shizuoka, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Harada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D018450:Disease Progression; D005260:Female; D006801:Humans; D016015:Logistic Models; D008214:Lymphocytes / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018384:Oxidative Stress / Q000187:drug effects; D010300:Parkinson Disease / Q000097:blood*
chemical_list: D015415:Biomarkers; D001205:Ascorbic Acid
keywords: Biomarkers; Clinical assessment; Oxidative stress; Parkinson's disease; Vitamin C