title: Elevated protein carbonyl and HIF-1α levels in eyes with proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To evaluate the role of protein carbonyls and hypoxia inducible factor-1α (HIF-1α) in diabetic eyes with proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Prospective consecutive controlled observational study was performed. Vitreous samples were collected at the start of the 3-ppp vitrectomy. Protein carbonylation analysis was performed by Western blotting with antibody against 2,4-Dinitrophenol (anti-DNP), following derivatization of protein carbonyls with 2,4 Dinitrophenylhydrazine (DNHP). Protein carbonylation was quantified by scanning densitometry analysis and relativized to the total amount of protein into the ponceau staining of membranes. Vitreous HIF-1 α was determined with ELISA in a subgroup of the samples. Thirty-one eyes were operated due to PDR (study group). Of the 189 controls, 39 had nonproliferative diabetic retinopathy (non-PDR), 111 retinal detachment (RD) and 39 macular hole/pucker (MH).
  
  
  RESULTS
  Comparison of eyes with PDR with controls revealed that the mean vitreous concentrations of protein carbonyls were significantly higher in the eyes affected with PDR being 242±130 (SD) compared with non-PDR controls 180±142, nondiabetic eyes affected with RD 175±131 and MH/pucker 140±95 (p=0.008, one-way anova). Mean HIF-1α values were higher in eyes with PDR compared with controls (RD, MH/pucker); the values being 0.53±0.34 (SEM; n=4) and 0.13±0.04 (SEM; n=19), respectively (p=0.009).
  
  
  CONCLUSIONS
  Protein carbonyl and HIF-1 α levels were significantly increased in the vitreous fluid of surgically treated eyes with PDR. Our findings suggest an association between increased intravitreal levels of protein carbonyls and the pathogenesis of PDR.
authors.affiliation: Unit of Vitreoretinal Surgery, Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, FinlandOulu Center for Cell-Matrix Research, Biocenter Oulu, Department of Medical Biochemistry and Molecular Biology, Oulu University, Oulu, FinlandDepartment of Physiology, University of Valencia, Spain, Valencia, SpainNeonatal Research Unit & Division of Neonatology, University and Polytechnic Hospital & Health Research Institute La Fe, Valencia, SpainDepartment of Pediatrics, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Sirpa
authors.initials: S
authors.lastname: Loukovaara
authors.forename: Peppi
authors.initials: P
authors.lastname: Koivunen
authors.forename: Marta
authors.initials: M
authors.lastname: Inglés
authors.forename: Javier
authors.initials: J
authors.lastname: Escobar
authors.forename: Maximo
authors.initials: M
authors.lastname: Vento
authors.forename: Sture
authors.initials: S
authors.lastname: Andersson
mesh_terms: D000328:Adult; D000368:Aged; D015153:Blotting, Western; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000601:surgery; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D011446:Prospective Studies; D050050:Protein Carbonylation / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D006442:Glycated Hemoglobin; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; C497442:HIF1A protein, human; C467484:VEGFA protein, human; C517652:hemoglobin A1c protein, human
keywords: Western blotting; hypoxia inducible factor 1α; oxidation; oxidative stress; proliferative diabetic retinopathy; protein carbonyls; vascular endothelial growth factor