title: Investigation of dynamic thiol-disulphide homoeostasis in age-related cataract patients with a novel and automated assay.
abstract: OBJECTIVE
  The aim of this study was to determine plasma thiol-disulphide homoeostasis in patients with age-related cataract (ARC) and compare the results of the patients with healthy subjects. Plasma malondialdehyde (MDA) levels and catalase (CAT) activity were also investigated.
  
  
  METHODS
  The study included 53 cataract patients and 52 healthy volunteers. Native thiol-disulphide exchanges were determined using a novel and automated method. CAT activity was determined using the method described by Aebi, and MDA levels were calculated using the thiobarbituric acid method.
  
  
  RESULTS
  Native thiol and total thiol levels were significantly lower in the cataract patients compared with the controls (p < 0.001, p = 0.002, respectively). The disulphide levels of the cataract patients were significantly higher than the controls (p = 0.002). The ratios of disulphide/native thiol and disulphide/total thiol were statistically higher in the cataract patients compared with the control group (p < 0.001, p < 0.001, respectively). Furthermore, CAT activity was significantly lower in the cataract patient group compared with the control group (p < 0.001), and MDA levels were insignificantly higher in the patient group (p = 0.581).
  
  
  CONCLUSIONS
  Our study showed that dynamic thiol-disulphide homoeostasis has shifted towards disulphide formation, as a result of thiol oxidation in ARC patients. The present study is the first to measure thiol-disulphide homoeostasis in ARC patients with a novel automated assay. This study supports the hypothesis that cataract is an oxidative disorder. Further studies are required in order to examine the relationship between oxidative stress and the development of cataract formation.
authors.affiliation: Department of Ophthalmology, Dumlupinar University School of Medicine, Kutahya, Turkey. dr.hsagdik@gmail.com.
authors.forename: Haci Murat
authors.initials: HM
authors.lastname: Sagdik
authors.affiliation: Department of Clinical Biochemistry, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey.
authors.forename: Fatma
authors.initials: F
authors.lastname: Ucar
authors.affiliation: Department of Ophthalmology, Dumlupinar University School of Medicine, Kutahya, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Tetikoglu
authors.affiliation: Department of Ophthalmology, Dumlupinar University School of Medicine, Kutahya, Turkey.
authors.forename: Serdar
authors.initials: S
authors.lastname: Aktas
authors.affiliation: Department of Ophthalmology, Dumlupinar University School of Medicine, Kutahya, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Ozcura
authors.affiliation: Department of Clinical Biochemistry, Dumlupinar University School of Medicine, Kutahya, Turkey.
authors.forename: Havva
authors.initials: H
authors.lastname: Kocak
authors.affiliation: Department of Clinical Biochemistry, Ataturk Training and Research Hospital, Ankara, Turkey.
authors.forename: Salim
authors.initials: S
authors.lastname: Neselioglu
authors.affiliation: Department of Clinical Biochemistry, Ataturk Training and Research Hospital, Ankara, Turkey.
authors.forename: Funda
authors.initials: F
authors.lastname: Eren
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002374:Catalase / Q000097:blood; D002386:Cataract / Q000097:blood* / Q000503:physiopathology; D004220:Disulfides / Q000097:blood*; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D013438:Sulfhydryl Compounds / Q000097:blood*
chemical_list: D004220:Disulfides; D013438:Sulfhydryl Compounds; D008315:Malondialdehyde; D002374:Catalase
keywords: Catalase; Cataract; Disulphide; Malondialdehyde; Oxidative stress; Thiol