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Selective loss of microvascular endothelial function in human hypercholesterolemia
D M Gilligan1, V Guetta, J A Panza
1Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md 20892.
Circulation
|July 1, 1994
Summary
Endothelial dysfunction in hypercholesterolemia selectively impairs nitric oxide production via acetylcholine pathways, but not bradykinin pathways. This suggests a targeted defect in vascular signaling rather than a generalized endothelial abnormality in patients with high cholesterol.
Area of Science:
- Cardiovascular Science
- Endothelial Function
- Vascular Biology
Background:
- Endothelial dysfunction is a key feature of vascular disease.
- Impaired endothelium-dependent vasodilation is observed in hypercholesterolemia.
- The specific pathways affected by this dysfunction are not fully understood.
Purpose of the Study:
- To investigate the nature of endothelial dysfunction in hypercholesterolemia.
- To compare vascular responses to agonists utilizing different nitric oxide production pathways.
- To determine if the defect is selective or generalized.
Main Methods:
- Compared forearm blood flow in 12 hypercholesterolemic patients and 12 healthy subjects.
- Administered acetylcholine (pertussis toxin-sensitive pathway) and bradykinin (pertussis toxin-insensitive pathway) via brachial artery infusion.
- Measured endothelium-independent vasodilation using sodium nitroprusside.
Main Results:
- Acetylcholine-induced vasodilation was significantly impaired in hypercholesterolemic patients.
- Bradykinin-induced vasodilation and sodium nitroprusside-induced vasodilation were similar in both groups.
- Nitric oxide synthesis inhibition affected bradykinin response equally in both groups.
Conclusions:
- Hypercholesterolemic patients maintain normal nitric oxide bioavailability in response to bradykinin.
- Endothelial vasodilator dysfunction in hypercholesterolemia is selective.
- The defect is localized to the acetylcholine receptor or its signal transduction pathway.