title: Aldose reductase inhibitor fidarestat prevents retinal oxidative stress and vascular endothelial growth factor overexpression in streptozotocin-diabetic rats.
abstract: The study addressed the role for aldose reductase (AR) in 1) retinal oxidative stress and vascular endothelial growth factor (VEGF) overexpression in early diabetes, and 2) high glucose-induced oxidative stress in retinal endothelial cells. In vivo experiments were performed on control rats and diabetic rats treated with or without low or high dose of the AR inhibitor (ARI) fidarestat (2 or 16 mg. kg(-1). day(-1)). In vitro studies were performed on bovine retinal endothelial cells (BREC) cultured in either 5 or 30 mmol/l glucose with or without 1 micro mol/l fidarestat. Intracellular reactive oxygen species were assessed using the 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) probe and flow cytometry. Both low and high doses of fidarestat (i.e., the doses that partially and completely inhibited sorbitol pathway hyperactivity) arrested diabetes-induced retinal lipid peroxidation. This was achieved due to upregulation of the key antioxidative defense enzyme activities rather than changes in reduced glutathione, oxidized glutathione, ascorbate and dehydroascorbate concentrations, and the glutathione and ascorbate redox states. Diabetes-associated 2.1-fold VEGF protein overexpression (enzyme-linked immunosorbent assay; ELISA) was dose-dependently prevented by fidarestat, whereas total VEGF mRNA and VEGF-164 mRNA (RT-PCR) abundance were not affected by either diabetes or the ARI. In BREC, fidarestat corrected hyperglycemia-induced increase in H(2)DCFDA fluorescence but not oxidative stress caused by three different pro-oxidants in normoglycemic conditions. In conclusion, increased AR activity contributes to retinal oxidative stress and VEGF protein overexpression in early diabetes. The findings justify the rationale for evaluation of fidarestat on diabetic retinopathy.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Michigan Medical Center, 1150 West Medical Center Drive, MSRB II, Room 5570, Ann Arbor, MI 48109-0678, USA. iobrosso@umich.edu
authors.forename: Irina G
authors.initials: IG
authors.lastname: Obrosova
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Minchenko
authors.forename: Rukmini
authors.initials: R
authors.lastname: Vasupuram
authors.forename: Lauren
authors.initials: L
authors.lastname: White
authors.forename: Omorodola I
authors.initials: OI
authors.lastname: Abatan
authors.forename: Arno K
authors.initials: AK
authors.lastname: Kumagai
authors.forename: Robert N
authors.initials: RN
authors.lastname: Frank
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Stevens
mesh_terms: D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors*; D043925:Angiogenesis Inducing Agents / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005434:Flow Cytometry; D005632:Fructose / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D007093:Imidazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D048289:Imidazolidines; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D012171:Retinal Vessels / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A
chemical_list: D043925:Angiogenesis Inducing Agents; D004791:Enzyme Inhibitors; D007093:Imidazoles; D048289:Imidazolidines; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D005632:Fructose; D013012:Sorbitol; C077139:fidarestat; D000449:Aldehyde Reductase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione; D005947:Glucose