title: Oxidative stress in diabetes-induced endothelial dysfunction involvement of nitric oxide and protein kinase C.
abstract: Reactive oxygen species (ROS) formation plays a major role in diabetes-induced endothelial dysfunction, though the molecular mechanism(s) involved and the contribution of nitric oxide (NO) are still unclear. This study using bovine retinal endothelial cells was aimed at assessing (i) the role of oxygen-dependent vs. NO-dependent oxidative stress in the endothelial cell permeability alterations induced by the diabetic milieu and (ii) whether protein kinase C (PKC) activation ultimately mediates these changes. Superoxide, lipid peroxide, and PKC activity were higher under high glucose (HG) vs. normal glucose throughout the 30 d period. Nitrite/nitrate and endothelial NO synthase levels increased at 1 d and decreased thereafter. Changes in monolayer permeability to 125I-BSA induced by 1 or 30 d incubation in HG or exposure to advanced glycosylation endproduct were reduced by treatment with antioxidants or PKC inhibitors, whereas NO blockade prevented only the effect of 1 d HG. HG-induced changes were mimicked by a PKC activator, a superoxide generating system, an NO and superoxide donor, or peroxynitrite (attenuated by PKC inhibition), but not a NO donor. The short-term effect of HG depends on a combined oxidative and nitrosative stress with peroxynitrite formation, whereas the long-term effect is related to ROS generation; in both cases, PKC ultimately mediates permeability changes.
authors.affiliation: Laboratory of Metabolism and Pathological Biochemistry, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Flavia
authors.initials: F
authors.lastname: Pricci
authors.forename: Gaetano
authors.initials: G
authors.lastname: Leto
authors.forename: Lorena
authors.initials: L
authors.lastname: Amadio
authors.forename: Carla
authors.initials: C
authors.lastname: Iacobini
authors.forename: Samantha
authors.initials: S
authors.lastname: Cordone
authors.forename: Stefania
authors.initials: S
authors.lastname: Catalano
authors.forename: Alessandra
authors.initials: A
authors.lastname: Zicari
authors.forename: Mariella
authors.initials: M
authors.lastname: Sorcini
authors.forename: Umberto
authors.initials: U
authors.lastname: Di Mario
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pugliese
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D018384:Oxidative Stress; D010539:Permeability; D011493:Protein Kinase C / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina
chemical_list: D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D011493:Protein Kinase C