Endothelial dysfunction is associated with cholesterol levels in the high normal range in humans

Area of Science:

• Cardiovascular Physiology
• Endothelial Function
• Lipid Metabolism

Background:

• Cholesterol's role in cardiovascular health is well-established, but its impact within the normal range on vascular function is less understood.
• Endothelial dysfunction is an early marker of atherosclerosis and macrovascular disease.

Purpose of the Study:

• To investigate the association between cholesterol levels within the normal range and endothelium-dependent vasodilation.
• To test the hypothesis that high-normal cholesterol is linked to impaired vascular function.

Main Methods:

• Assessed leg blood flow (LBF) responses to endothelium-dependent (methacholine chloride) and endothelium-independent (sodium nitroprusside) vasodilators.
• Recruited healthy volunteers with a wide spectrum of total cholesterol levels within the normal range.
• Compared LBF responses between subjects with low-normal and high-normal cholesterol levels.

Main Results:

• Leg blood flow (LBF) increased dose-dependently with both vasodilators.
• Endothelium-dependent vasodilation was significantly blunted in subjects with high-normal cholesterol compared to low-normal cholesterol.
• Maximal endothelium-dependent vasodilation was reduced by nearly 50% in the high-normal cholesterol group.
• A significant negative correlation was observed between total cholesterol and LDL cholesterol levels and maximal endothelium-dependent vasodilation.
• No significant difference in response to the endothelium-independent vasodilator was found between groups.

Conclusions:

• An inverse relationship exists between cholesterol levels and endothelium-dependent vasodilation.
• Cholesterol levels within the normal range may be associated with endothelial dysfunction.
• This subclinical endothelial dysfunction could contribute to the increased risk of macrovascular disease associated with elevated cholesterol.