title: Vitreous levels of reactive oxygen species in proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To investigate vitreous levels of reactive oxygen species (ROS) in patients with proliferative diabetic retinopathy (PDR) and analyze ROS levels among different groups of PDR patients.
  
  
  METHODS
  Retrospective case-control study.
  
  
  METHODS
  Thirty-nine eyes of 39 patients with PDR and 16 eyes of 16 non-PDR patients (control group) that underwent primary vitrectomy for complications of PDR and other conditions (control group), with a follow-up time > or = 12 months.
  
  
  METHODS
  Proliferative diabetic retinopathy patients were classified into 3 groups according to the extent of fibrovascular proliferation: (1) no or focal adhesions at < or =3 sites (n = 17); (2) > or =1 broad adhesions or vitreous-retinal adhesions around disc, macula, and arcade (n = 12); and (3) vitreous-retinal attachment extending to the periphery or no posterior vitreous detachment with or without retinal detachment (RD) (n = 10). The control group (n = 16) contained non-PDR patients. Vitreous samples were obtained during measurement of vitrectomy and vitreous levels of ROS by luminol-enhanced chemiluminescence assay.
  
  
  METHODS
  Reactive oxygen species levels were recorded as mean (+/- standard deviation) chemiluminescence counts per 10 seconds. Correlations of vitreous levels of ROS among the 3 PDR groups and anatomic prognosis were evaluated. Multiple linear regression analysis of selective potential risk factors was performed to investigate the main determinants of ROS levels.
  
  
  RESULTS
  Vitreous ROS levels were significantly higher in patients with PDR (125.76+/-351.72 chemiluminescence counts per 10 seconds) than in control patients (0.37+/-0.72 chemiluminescence counts per 10 seconds; P<0.0001). Reactive oxygen species levels were 1.86+/-1.63 (group 1), 24.47+/-22.68 (group 2), and 457.94+/-597.01 (group 3); the difference among groups was significant (P = 0.001). Regression analysis indicated that only patient grouping (according to the severity of fibrovascular proliferation) had a strong dependent association with ROS levels (P = 0.001). Final anatomic results revealed that recurrent untreatable RD occurred in 3 patients of group 3, who also had the highest ROS levels.
  
  
  CONCLUSIONS
  Reactive oxygen species levels were significantly elevated in the vitreous fluid of PDR patients, and patients with a more advanced clinical PDR appearance had higher ROS levels. These findings suggest an association between ROS and the pathogenesis of PDR. Reactive oxygen species might be correlated with PDR severity.
authors.affiliation: Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Po-Ting
authors.initials: PT
authors.lastname: Yeh
authors.forename: Chung-May
authors.initials: CM
authors.lastname: Yang
authors.forename: Jen-Shang
authors.initials: JS
authors.lastname: Huang
authors.forename: Chiang-Ting
authors.initials: CT
authors.lastname: Chien
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Yang
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Chiang
authors.forename: Yung-Feng
authors.initials: YF
authors.lastname: Shih
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D018450:Disease Progression; D005260:Female; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species