AVE3085 protects coronary endothelium from the impairment of asymmetric dimethylarginine by activation and recoupling of eNOS.
OBJECTIVE
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of eNOS and it is recognized as a risk factor for endothelial dysfunction in cardiovascular diseases. We investigated the effect of AVE3085, a newly developed transcription enhancer of eNOS, on ADMA-induced endothelial dysfunction in coronary arteries with underlying mechanisms explored.


METHODS
Porcine coronary small arteries (diameter 600-800 μm) were studied in a myograph for endothelium-dependent relaxation to bradykinin and endothelium-independent relaxation to sodium nitroprusside. Protein expressions of eNOS and phosphorylated-eNOS (p-eNOS(Ser1177) and p-eNOS(Thr495)), and nitrotyrosine formation were determined by Western blot. NO release was directly measured with a NO microsensor. Productions of O(2) (.-) and peroxynitrite (ONOO(-)) were determined by lucigenin- and luminol- enhanced chemiluminescence respectively.


RESULTS
Exposure to ADMA significantly decreased the bradykinin-induced vasorelaxation and reduced the protein expression of p-eNOS(Ser1177) whereas increased the expression of p-eNOS(Thr495) and nitrotyrosine. Pre-incubation with AVE3085 restored the bradykinin-induced relaxation, reversed the decrease of p-eNOS(Ser1177), and lowered the level of p-eNOS(Thr495) and nitrotyrosine. NO release in response to bradykinin was significantly reduced by ADMA and such reduction was restored by AVE3085. AVE3085 also prevented the elevation of O (2) (.-) and ONOO(-) levels in coronary arteries exposed to ADMA.


CONCLUSIONS
AVE3085 prevents ADMA-induced endothelial dysfunction in coronary arteries. The protective effect of AVE3085 may be attributed to increased NO production resulting from enhanced eNOS activation, and decreased oxidative stress that involves inhibition of O (2) (.-) generation by eNOS recoupling. The present study suggested the therapeutic potential of AVE3085 in endothelial dysfunction in cardiovascular disorders.
Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Block B, 5A, Shatin, NT, Hong Kong.
Hong-Mei
HM
Xue
Cheuk-Man
CM
Yu
Malcolm John
MJ
Underwood
Jun-Hao
JH
Huang
Qin
Q
Yang
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives; D052117:Benzodioxoles / Q000494:pharmacology*; D002316:Cardiotonic Agents / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology; D066298:In Vitro Techniques; D007189:Indans / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013552:Swine; D014664:Vasodilation / Q000187:drug effects
C528910:2,2-difluorobenzo(1,3)dioxole-5-carboxylic acid indan-2-ylamide; D052117:Benzodioxoles; D002316:Cardiotonic Agents; D007189:Indans; D013481:Superoxides; D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D001120:Arginine; D052250:Nitric Oxide Synthase Type III; D010100:Oxygen