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Impaired endothelium-dependent vasodilation of coronary resistance vessels in hypercholesterolemic patients
1First Department of Internal Medicine, Hiroshima University School of Medicine.
Insights
High cholesterol impairs blood vessel function. This study shows hypercholesterolemia reduces endothelium-dependent vasodilation in coronary resistance vessels, even without artery blockages.
Area of Science:
- Cardiovascular Medicine
- Vascular Biology
- Metabolic Disorders
Background:
- Hypercholesterolemia is a significant risk factor for cardiovascular disease.
- Endothelial dysfunction is an early event in atherogenesis.
- The impact of hypercholesterolemia on coronary resistance vessel function requires further elucidation.
Purpose of the Study:
- To investigate the relationship between hypercholesterolemia and endothelial function in coronary resistance vessels.
- To assess coronary blood flow responses to endothelium-dependent and -independent vasodilators in hypercholesterolemic patients.
Main Methods:
- Coronary blood flow (CBF) was measured in patients with hypercholesterolemia (n=17) and controls (n=17).
- Infusions of acetylcholine (endothelium-dependent) and adenosine (endothelium-independent) were administered.
- Changes in CBF were analyzed in relation to serum cholesterol levels.
Main Results:
- Acetylcholine-induced increases in CBF were significantly smaller in hypercholesterolemic patients compared to controls.
- Maximal acetylcholine-induced CBF increase was inversely correlated with serum cholesterol levels (r = -0.55, p < 0.01).
- Adenosine-induced increases in CBF were similar between the groups, indicating preserved endothelium-independent vasodilation.
Conclusions:
- Hypercholesterolemia impairs endothelium-dependent vasodilation in coronary resistance vessels.
- This dysfunction occurs early, preceding atherosclerotic lesions in epicardial arteries.
- Endothelial function of coronary resistance vessels is compromised in hypercholesterolemia.
Abstract:
To determine the relationship between hypercholesterolemia and the endothelial function of coronary resistance vessels, we studied the changes in coronary blood flow (CBF) in response to acetylcholine, an endothelium-dependent vasodilator, and adenosine, an endothelium-independent vasodilator, in patients with hypercholesterolemia (n = 17) and in control patients (n = 17). All patients had normal epicardial coronary arteries. Serial 2-min infusions of acetylcholine, at 3 micrograms/min and 30 micrograms/min, caused a dose-dependent increase in CBF in each group. The acetylcholine-induced maximal increases in CBF were inversely correlated with the serum cholesterol level (r = -0.55, p < 0.01), and were significantly smaller in the hypercholesterolemic patients than in control patients. However, the adenosine-induced increases in CBF were similar in the two groups. These results suggest that the endothelium-dependent vasodilation of resistance vessels is lessened in patients with hypercholesterolemia even before the formation of atherosclerotic stenotic lesions in epicardial coronary arteries, and that hypercholesterolemia impairs endothelium-dependent vasodilation of coronary resistance vessels.