title: Serum levels of homocysteine, asymmetric dimethylarginine and nitric oxide in patients with Parkinson's disease.
abstract: OBJECTIVE
  Endothelial dysfunction has been implicated as a crucial event in the development of several neurodegenerative diseases. The aim of this study was to investigate the serum homocysteine, asymmetric dimethylarginine (ADMA) and nitric oxide (NO) levels in patients with Parkinson's disease (PD) and to compare the results with data from healthy controls.
  
  
  METHODS
  A total of 132 subjects, including 82 idiopathic PD patients who were newly diagnosed and untreated (47 males, 35 females, mean age of 60.8 ± 7.1 years) and 50 healthy controls (28 males, 22 females, mean age of 60.2 ± 6.7 years) were enrolled in this study. The serum ADMA and NO levels were determined using enzyme-linked immunosorbent assay (ELISA), while the homocysteine levels were determined by chemiluminescent microparticle immunoassay.
  
  
  RESULTS
  The ADMA and NO levels of the PD patients were significantly higher than those of the healthy controls. The serum ADMA levels were 0.70 ± 0.15 μmol/L in the PD patients and 0.50 ± 0.12 μmol/L in the healthy controls (p < 0.001). The serum NO levels were 78.7 ± 10.3 μmol/L in the PD patients and 59.9 ± 9.5 μmol/L in the healthy controls (p < 0.001). In addition, the ADMA and NO levels were significantly correlated with the serum homocysteine levels in patients with PD (r = 0.874, p < 0.001, r = 0.803, p = 0.005, respectively).
  
  
  CONCLUSIONS
  In our study, the high ADMA and NO levels of patients with PD indicate endothelial dysfunction, and this dysfunction may play a role in PD pathogenesis. Larger studies, including randomised clinical trials in humans and animal studies, are needed to validate our findings and help in developing a better understanding of the pathogenesis of PD.
authors.affiliation: a Faculty of Medicine, Department of Neurology , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Serkan
authors.initials: S
authors.lastname: Kirbas
authors.affiliation: b Faculty of Medicine, Department of Biochemistry , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Aynur
authors.initials: A
authors.lastname: Kirbas
authors.affiliation: a Faculty of Medicine, Department of Neurology , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Tufekci
authors.affiliation: b Faculty of Medicine, Department of Biochemistry , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Medine
authors.initials: M
authors.lastname: Cumhur Cure
authors.affiliation: a Faculty of Medicine, Department of Neurology , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Sevim
authors.initials: S
authors.lastname: Cakmak
authors.affiliation: b Faculty of Medicine, Department of Biochemistry , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Tarkan
authors.initials: T
authors.lastname: Yazici
authors.affiliation: c Faculty of Medicine, Department of Internal Medicine , Recep Tayyip Erdogan University , Rize , Turkey.
authors.forename: Erkan
authors.initials: E
authors.lastname: Cure
mesh_terms: D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000503:physiopathology; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood*; D010300:Parkinson Disease / Q000097:blood* / Q000503:physiopathology
chemical_list: D006710:Homocysteine; D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D001120:Arginine
keywords: Asymmetric dimethylarginine; Homocysteine; Nitric oxide; Parkinson’s disease