In vivo gene transfer of inducible nitric oxide synthase to carotid arteries from hypercholesterolemic rabbits.
OBJECTIVE
Hypercholesterolemia is associated with endothelial dysfunction. Inducible nitric oxide synthase (iNOS) is upregulated in atherosclerotic vessels. However, its role in the regulation of vascular function is not completely understood. We examined the effect of adenovirus-mediated gene transfer of iNOS to the hypercholesterolemic rabbit carotid artery in vivo.


METHODS
Rabbits were fed a high-cholesterol or chow diet for 10 weeks. Two doses (1x10(8) and 1x10(9) plaque-forming units [pfu]/mL) of adenoviral vectors encoding iNOS (AdiNOS) or beta-galactosidase (Ad(beta)gal) were luminally delivered to the carotid arteries from chow- and cholesterol-fed animals. Vascular reactivity and superoxide levels were assessed in Ad(beta)gal- and AdiNOS-transduced vessels from chow- and cholesterol-fed animals after 3 days.


RESULTS
Endothelium-dependent vasorelaxation was impaired in the carotid artery from cholesterol-fed animals. In AdiNOS-transduced arteries, transgene expression was demonstrated by positive immunostaining in the endothelium. Transduction with low-dose (1x10(8) pfu/mL) AdiNOS did not affect vascular reactivity in arteries from chow- and cholesterol-fed animals. In contrast, high-dose (1x10(9) pfu/mL) AdiNOS significantly reduced endothelium-dependent relaxation in vessels from cholesterol- but not chow-fed rabbits. After both low- and high-dose iNOS gene transfer, levels of O2*(-) were significantly (P<0.05) elevated in carotid arteries from cholesterol-fed animals. Incubation with an O2*(-) scavenger did not reverse vascular dysfunction in these arteries.


CONCLUSIONS
Adenoviral-mediated overexpression of iNOS results in increased production of O2*(-) in carotid arteries from cholesterol- but not chow-fed animals. High-dose AdiNOS gene transfer is associated with reduced endothelium-dependent and -independent relaxation in vessels from cholesterol-fed animals.
Zanetti
Michela
M
Department of Endocrinology, Mayo Clinic and Foundation, Rochester, Minn., USA.
d'Uscio
Livius V
LV
Kovesdi
Imre
I
Katusic
Zvonimir S
ZS
O'Brien
Timothy
T
D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002339:Carotid Arteries / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000633:toxicity; D003587:Cytomegalovirus / Q000235:genetics; D004036:Diet, Atherogenic; D004730:Endothelium, Vascular / Q000502:physiology; D017930:Genes, Reporter; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D006937:Hypercholesterolemia / Q000201:enzymology / Q000209:etiology / Q000628:therapy*; D007763:Lac Operon; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D010656:Phenylephrine / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013481:Superoxides / Q000378:metabolism; D014161:Transduction, Genetic; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D002791:Cholesterol, Dietary; D011993:Recombinant Fusion Proteins; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D013481:Superoxides; D010656:Phenylephrine; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D000109:Acetylcholine