title: Plasma homocysteine and total thiol content in patients with exudative age-related macular degeneration.
abstract: OBJECTIVE
  Exudative age-related macular degeneration (ARMD) is one of the debilitating ocular complications, which results in permanent blindness. Elevated homocysteine (Hcys) levels have been associated in the development of several vascular diseases. Vascular and oxidative stress theories have been implicated for the development of choroidal neovascularization in exudative ARMD. The aim of the present study was to investigate the possible role of plasma Hcys and thiol content (tSH) as a risk factor for the development of exudative ARMD.
  
  
  METHODS
  A total of 16 patients with exudative ARMD and 20 age-matched controls were recruited for the study. Plasma Hcys levels were analysed using Reverse Phase High Performance Liquid Chromatography. Plasma glutathione (GSH) content was determined using o-phthalaldehyde (OPA) derivatization and subsequent detection by fluorimeter. Plasma tSH levels were determined by using thiol-specific reagent dithionitrobenzoic acid (DTNB) spectrophotometrically.
  
  
  RESULTS
  Plasma Hcys levels in exudative ARMD were elevated three-fold (18+/-5.0 microM) when compared to healthy controls (6.7+/-1.8 microM). There was a two-fold decrease in the GSH and tSH in exudative ARMD when compared with controls. Negative correlation was observed between diminished tSH and Hcys levels (r=-0.4837, P=0.05). Similarly plasma Hcys levels negatively correlated with GSH content (r=-0.6620, P<0.05).
  
  
  CONCLUSIONS
  Results from our present study revealed that there is an elevated Hcys level and diminished thiol pool content in exudative ARMD that are significant.
authors.affiliation: Biochemistry Research Department, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: K
authors.initials: K
authors.lastname: Coral
authors.forename: R
authors.initials: R
authors.lastname: Raman
authors.forename: S
authors.initials: S
authors.lastname: Rathi
authors.forename: M
authors.initials: M
authors.lastname: Rajesh
authors.forename: K N
authors.initials: KN
authors.lastname: Sulochana
authors.forename: N
authors.initials: N
authors.lastname: Angayarkanni
authors.forename: P G
authors.initials: PG
authors.lastname: Paul
authors.forename: S
authors.initials: S
authors.lastname: Ramakrishnan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D005978:Glutathione / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008268:Macular Degeneration / Q000097:blood*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D012307:Risk Factors; D013438:Sulfhydryl Compounds / Q000097:blood*
chemical_list: D015415:Biomarkers; D013438:Sulfhydryl Compounds; D006710:Homocysteine; D005978:Glutathione