title: Endothelial nitric oxide synthase enhancer reduces oxidative stress and restores endothelial function in db/db mice.
abstract: OBJECTIVE
  Endothelial dysfunction is caused by reduced nitric oxide (NO) bioavailability and/or over-produced reactive oxygen species (ROS). The present study investigated a vascular benefit of AVE3085, an endothelial nitric oxide synthase (eNOS) enhancer, in preserving endothelial function in diabetic mice and the mechanisms involved.
  
  
  RESULTS
  Male db/db and db/m(+) mice were orally administered AVE3085 for 7 days (10 mg kg(-1) day(-1)). Vascular reactivity of arteries was studied via myography under both isometric and isobaric conditions. ROS levels in aortas were determined using dihydroethidium fluorescence dye and electron paramagnetic resonance spin trapping. Chronic treatment with AVE3085 reduced blood pressure, enhanced endothelium-dependent relaxations (EDR) to acetylcholine in aortas, mesenteric, and renal arteries, lowered oxidative stress, and augmented the attenuated flow-dependent dilatation in mesenteric resistance arteries from db/db mice. Incubation of aortas from C57BL/6J mice in high glucose (30 mmol L(-1)) culture medium for 48 h impaired EDR and elevated ROS generation, and these effects were reversed by co-treatment with AVE3085 (1 µmol L(-1)). Benefits of AVE3085 were abolished by the transcription inhibitor actinomycin D, the NOS inhibitor N(G)-nitro-L-arginine methyl ester, and in eNOS(-/-) mice. NO production in primary endothelial cells from mouse aortas was detected with a NO-sensitive fluorescence dye. Protein expression was assayed by western blotting. Treatment with AVE3085 enhanced NO production in endothelial cells and eNOS expression in aortas.
  
  
  CONCLUSIONS
  AVE3085 ameliorates endothelial dysfunction in db/db mice through increased NO bioavailability, which reduces oxidative stress in the vascular wall. Targeting eNOS and NO production may be a promising approach to combat diabetic vasculopathy.
authors.affiliation: Li Ka Shing Institute of Health Sciences, Institute of Vascular Medicine, and School of Biomedical Sciences,  Chinese University of Hong Kong, Shatin, N.T., Hong Kong,  China.
authors.forename: Wai San
authors.initials: WS
authors.lastname: Cheang
authors.forename: Wing Tak
authors.initials: WT
authors.lastname: Wong
authors.forename: Xiao Yu
authors.initials: XY
authors.lastname: Tian
authors.forename: Qin
authors.initials: Q
authors.lastname: Yang
authors.forename: Hung Kay
authors.initials: HK
authors.lastname: Lee
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: He
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Yao
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D052117:Benzodioxoles / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D003925:Diabetic Angiopathies / Q000188:drug therapy* / Q000201:enzymology / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000503:physiopathology; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000008:administration & dosage / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D007189:Indans / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009213:Myography; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D013997:Time Factors; D046509:Tissue Culture Techniques; D015854:Up-Regulation; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: C528910:2,2-difluorobenzo(1,3)dioxole-5-carboxylic acid indan-2-ylamide; D000975:Antioxidants; D052117:Benzodioxoles; D020536:Enzyme Activators; D007189:Indans; D014665:Vasodilator Agents; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D005947:Glucose