title: Diabetes-induced oxidative stress in the vitreous humor.
abstract: Diabetes is accompanied by fundamental rearrangements in redox homeostasis. Hyperglycemia triggers the production of reactive oxygen and nitrogen species which contributes to tissue damage in various target organs. Proliferative diabetic retinopathy (PDR) is a common manifestation of diabetic complications but information on the possible role of reactive intermediates in this condition with special regard to the involvement of the vitreous in PDR-associated redox alterations is scarce. The aim of the study was to determine key parameters of redox homeostasis [advanced glycation endproducts (AGE); protein carbonyl and glutathione (GSH)] content in the vitreous in PDR patients.
  
  
  
  The study population involved 10 diabetic patients undergoing surgery for complications of proliferative diabetic retinopathy and 8 control (non-diabetic) patients who were undergoing surgery for epiretinal membranes. Vitreal fluids were assayed for the above biochemical parameters.
  
  
  
  We found elevated levels of AGE in the vitreous of PDR patients (812.10 vs 491.69ng AGE/mg protein). Extent of protein carbonylation was also higher in the samples of diabetic patients (2.08 vs 0.67A/100μg protein). The GSH content also increased in the vitreous of PDR patients as compared to the control group (4.54 vs 2.35μmol/μg protein), respectively.
  
  
  
  The study demonstrates that diabetes-associated redox alterations also reach the vitreous with the most prominent changes being increased protein carbonylation and increased antioxidant levels.
authors.affiliation: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Géhl
authors.affiliation: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Edina
authors.initials: E
authors.lastname: Bakondi
authors.affiliation: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors.forename: Miklós D
authors.initials: MD
authors.lastname: Resch
authors.affiliation: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Hegedűs
authors.affiliation: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; MTA-DE Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Debrecen, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Kovács
authors.affiliation: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Petra
authors.initials: P
authors.lastname: Lakatos
authors.affiliation: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors.forename: Antal
authors.initials: A
authors.lastname: Szabó
authors.affiliation: Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Nagy
authors.affiliation: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; MTA-DE Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Debrecen, Hungary. Electronic address: lvirag@med.unideb.hu.
authors.forename: László
authors.initials: L
authors.lastname: Virág
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005978:Glutathione / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D050050:Protein Carbonylation; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D017127:Glycation End Products, Advanced; D005978:Glutathione
keywords: Advanced glycation endproducts; Antioxidants; Diabetes; Glutathion; Protein carbonylation; Protein oxidation; Vitreous