Mechanisms underlying dysfunction of carotid arteries in genetically hyperlipidemic rabbits.
In the present study we compared the vascular reactivity and integrity of the nitric oxide (NO)-cyclic 3',5'-guanosine monophopsphate (cGMP) pathway in carotid arteries of hyper- and normolipidemic rabbits. Vasodilation to acetylcholine, nitroglycerin, and sodium nitroprusside was desensitized in hyperlipidemia, but the nitroprusside-induced relaxation was normalized by an NO synthase inhibitor in endothelium-intact and -denuded vessels. Hyperlipidemic carotid arteries exhibited increased basal NO (detected by EPR spin-trapping) and reactive oxygen species formation (detected by chemiluminescence), whereas acetylcholine-induced NO formation was nearly abolished. Hyperlipidemia increased NADPH-dependent superoxide formation in carotid membranes, and carotid cryosections stained with the fluorescent dye dihydroethidium revealed increased endothelial and medial reactive oxygen species formation. Hyperlipidemia elicited macrophage invasion into the carotid wall, as detected by a dot-immunoblot. The basal activity of cGMP-dependent proteinkinase, the nitroprusside-stimulated activity of soluble guanylyl cyclase, and its protein expression were decreased by hyperlipidemia. The cGMP phosphodiesterase activity was marginally increased by hyperlipidemia, such that the ratio of cGMP-forming vs. -degrading capacity was decreased by 2-fold. Hyperlipidemia triggers infiltration of macrophages into the carotid wall and endothelial as well as smooth muscle superoxide formation. Consequently, relaxation of the carotid arteries are impaired due to smooth muscle and endothelial dysfunction.
August
Michael
M
University Hospital Eppendorf, Division of Cardiology, Hamburg, Germany.
Wingerter
Oliver
O
Oelze
Matthias
M
Wenzel
Philip
P
Kleschyov
Andrei L
AL
Daiber
Andreas
A
Mülsch
Alexander
A
Münzel
Thomas
T
Tsilimingas
Nikolaos
N
D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D006949:Hyperlipidemias; D008264:Macrophages / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology; D000098662:Vasodilator-Stimulated Phosphoprotein
D015815:Cell Adhesion Molecules; D004791:Enzyme Inhibitors; D008840:Microfilament Proteins; D020030:Nitric Oxide Donors; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D000098662:Vasodilator-Stimulated Phosphoprotein; D009599:Nitroprusside; D009569:Nitric Oxide; D010727:Phosphoric Diester Hydrolases; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester