Gene transfer of endothelial nitric oxide synthase improves relaxation of carotid arteries from diabetic rabbits.
BACKGROUND
Diabetes mellitus is associated with impairment of NO-mediated vascular relaxation. The purpose of this study was to determine whether adenovirus-mediated gene transfer of endothelial NO synthase (eNOS) or Cu/Zn superoxide dismutase (SOD1) improves responsiveness to acetylcholine in alloxan-induced diabetic rabbits.


RESULTS
After 8 weeks, plasma glucose was greater in diabetic rabbits (418+/-35 mg/dL) (mean+/-SEM) than in normal rabbits (105+/-4 mg/dL). Carotid arteries were removed and cut into ring segments. Arteries were incubated for 2 hours with adenoviral vectors driven by a CMV promoter expressing beta-galactosidase (beta-gal), eNOS, SOD1, or vehicle. After incubation with virus, arteries were incubated for an additional 24 hours to allow transgene expression. Vascular reactivity was examined by recording isometric tension. After precontraction with phenylephrine, responses to the endothelium-independent vasodilator sodium nitroprusside were similar in diabetic and normal arteries. Endothelium-dependent relaxation to acetylcholine (3x10(-6) mol/L) was significantly less in arteries from diabetic animals (68+/-5%) than in normal vessels (90+/-3%). Adenoviral transfection of arteries with eNOS improved relaxation in response to acetylcholine in diabetic (EC(50) eNOS=0.64+/-0.12x10(-7) mol/L versus vehicle =1. 70+/-0.43x10(-7) mol/L) but not normal arteries. Vasorelaxation in response to acetylcholine was inhibited by N(omega)-nitro-L-arginine (100 micromol/L) in all groups. Responses to acetylcholine were unchanged after gene transfection of SOD1 or beta-gal in arteries from diabetic or normal rabbits.


CONCLUSIONS
Adenovirus-mediated gene transfer of eNOS, but not SOD, improves impaired NO-mediated relaxation in vessels from diabetic rabbits.
Lund
D D
DD
Departments of Internal Medicine and Pharmacology and the Cardiovascular Center, University of Iowa College of Medicine and Veterans Affairs Medical Center, Iowa City 52242, USA.
Faraci
F M
FM
Miller
F J
FJ
Heistad
D D
DD
D000109:Acetylcholine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology*; D018014:Gene Transfer Techniques; D008297:Male; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D011817:Rabbits; D013481:Superoxides / Q000378:metabolism; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014666:Vasomotor System / Q000503:physiopathology; D001616:beta-Galactosidase / Q000378:metabolism
D014665:Vasodilator Agents; D013481:Superoxides; D019335:Nitroarginine; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D001616:beta-Galactosidase; D000109:Acetylcholine