title: Comparison of serum thiol-disulphide homeostasis and total antioxidant-oxidant levels between exudative age-related macular degeneration patients and healthy subjects.
abstract: OBJECTIVE
  The purpose of the study was to calculate serum total oxidant status (TOS), total antioxidant status (TAS), and dynamic thiol-disulphide (T-D) homeostasis in patients with age-related macular degeneration (AMD), and compare the results with healthy individuals.
  
  
  METHODS
  Thirty-three exudative AMD patients and 33 healthy controls were included in this case-control study. Participants' serum TAS and TOS levels were measured. In addition, total thiol (TT), native thiol (NT), and disulphide (DS) concentrations were assessed using a novel automated method of measurement.
  
  
  RESULTS
  In comparison with the control group, serum TAS, TT, and NT levels were found to be significantly lower (p < 0.0001, p = 0.004, p = 0.003, respectively) and TOS levels were detected higher (p = 0.032) in AMD patients. Serum DS levels were elevated in the AMD patient group, but the difference was not statistically significant (p = 0.219). DS/TT and DS/NT ratios were significantly higher (p = 0.012, p = 0.013, respectively) in AMD patients. A positive correlation was found between TT and NT (p < 0.0001) in AMD group.
  
  
  CONCLUSIONS
  Serum TOS levels are higher, TAS levels are lower, and the T-D balance is shifted to the DS bond side in AMD patients. These results suggest that increased oxidative stress and decreased antioxidant levels may play a role in AMD progression. Further studies are needed to confirm the pathophysiologic role of T-D homeostasis in AMD.
authors.affiliation: Department of Ophthalmology, Bezmialem University School of Medicine, Zümrütevler Mh. Yol-6 Sk. No:2 Seyrantepe Konutları A4/52 Maltepe, Istanbul, Turkey. elbayamd@gmail.com.
authors.forename: Ahmet
authors.identifier: http://orcid.org/0000-0002-8584-1866
authors.initials: A
authors.lastname: Elbay
authors.affiliation: Department of Biochemistry, Bezmialem University School of Medicine, Istanbul, Turkey.
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Ozer
authors.affiliation: Department of Ophthalmology, Bezmialem University School of Medicine, Zümrütevler Mh. Yol-6 Sk. No:2 Seyrantepe Konutları A4/52 Maltepe, Istanbul, Turkey.
authors.forename: Julide Canan Umurhan
authors.initials: JCU
authors.lastname: Akkan
authors.affiliation: Department of Ophthalmology, Istanbul Medeniyet University School of Medicine, Istanbul, Turkey.
authors.forename: Ugur
authors.initials: U
authors.lastname: Celik
authors.affiliation: Department of Ophthalmology, Umraniye Training and Research Hospital, Istanbul, Turkey.
authors.forename: Işıl
authors.initials: I
authors.lastname: Kutlutürk
authors.affiliation: Department of Ophthalmology, Bezmialem University School of Medicine, Zümrütevler Mh. Yol-6 Sk. No:2 Seyrantepe Konutları A4/52 Maltepe, Istanbul, Turkey.
authors.forename: Arif
authors.initials: A
authors.lastname: Koytak
authors.affiliation: Department of Ophthalmology, Bezmialem University School of Medicine, Zümrütevler Mh. Yol-6 Sk. No:2 Seyrantepe Konutları A4/52 Maltepe, Istanbul, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Ozdemir
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood; D004220:Disulfides / Q000097:blood*; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008266:Macula Lutea / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000097:blood*; D018384:Oxidative Stress; D012189:Retrospective Studies; D013438:Sulfhydryl Compounds / Q000097:blood*; D041623:Tomography, Optical Coherence; D057135:Wet Macular Degeneration / Q000097:blood* / Q000175:diagnosis
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D004220:Disulfides; D016877:Oxidants; D013438:Sulfhydryl Compounds
keywords: Age-related macular degeneration; Native thiol; Thiol–disulphide homeostasis; Total antioxidant status; Total oxidant status