| Research Abstract |
1. The methods of evaluation of vascular endothelial function in humans are different among different laboratories. In order to establish the evaluation method of endothelial function, we have standardized the measurement of endothelium-dependent and -independent vasodilation, evaluated the reference value, and studied the effects of several risk factors for atherosclerosis.
2. Using high resolution ultrasound, we determined the response of brachial artery to hyperemia (Flow mediated vasodilation : FMD) as endothelium-dependent vasodilation and the response to sublingual spray of nitroglycerine (NTG) as endothelium-independent vasocilation in healthy subjects and patients with risk factors for atherosclerosis. Reactive hyperemia was evoked by release of cuff inflated to 200 mmHg for 5 minutes on the upper arm.
3. The peak response was achieved about 1 minute after hyperemia and about 2〜3 minutes after NTG. As in 90% of healthy subjects, both FMD and the response to NTG ranged between 10 and 15%, these values are considered as the reference range.
4. In healthy subjects, there was no gender difference in FMD or the response to NTG. Age was significantly and negatively correlated with FMD and the response to NTG, but had no relation to the index of endothelial function (the ratio of FMD to NTG).
5. In comparison with healthy subjects, FMD and EFI were decreased in patients with essential hypertension, diabetes and hyperlipidemia, but the response to NTG were similar in all groups.
6. We have established the method to evaluate the endothelial function of brachial artery in humans as the routine clinical laboratory examination. We clarified that the vascular response is decreased with aging, and endothelial function was disturbed in risk factors for atherosclerosis.
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