Changes in flow-mediated brachial artery vasoactivity with lowering of desirable cholesterol levels in healthy middle-aged men
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R A Vogel1, M C Corretti, G D Plotnick
1Department of Medicine, University of Maryland School of Medicine, Baltimore, USA.
Insights
Lowering cholesterol below recommended levels significantly improves vascular function in healthy men. This study shows enhanced brachial artery vasoactivity with cholesterol reduction, indicating improved endothelial health.
Area of Science:
- Cardiovascular Medicine
- Endocrinology
- Vascular Biology
Background:
- Current National Cholesterol Education Program guidelines define desirable cholesterol levels for healthy individuals.
- The impact of cholesterol levels within these recommendations on vascular function is not fully understood.
Purpose of the Study:
- To investigate the effect of lowering cholesterol levels below current guidelines on flow-mediated brachial artery vasoactivity.
- To assess the rapid response of endothelial function to cholesterol reduction.
Main Methods:
- Noninvasive assessment of flow-mediated brachial artery vasoactivity using ultrasound.
- Cholesterol levels were lowered using simvastatin (10 mg/day) in 7 healthy middle-aged men.
- Measurements were taken before, during, and after cholesterol-lowering therapy.
Main Results:
- Flow-mediated vasoactivity significantly increased as cholesterol levels decreased below recommended values (p < 0.05).
- Vasoactivity showed an inverse correlation with cholesterol levels (r = -0.47, p = 0.004).
- Vasoactivity and cholesterol levels returned to baseline after discontinuation of simvastatin.
Conclusions:
- Flow-mediated brachial artery vasoactivity is sensitive to cholesterol levels, improving as cholesterol decreases.
- Lowering cholesterol below current guidelines enhances endothelial function.
- These findings suggest potential benefits of more aggressive cholesterol management for vascular health.
Abstract:
Current National Cholesterol Education Program guidelines consider desirable total and low-density lipoprotein cholesterol levels to be < 200 and < 160 mg/dl, respectively, for healthy individuals without multiple coronary risk factors. To determine the extent to which these levels affect vascular function, we assessed flow-mediated (endothelium-dependent) brachial artery vasoactivity noninvasively before, during, and after cholesterol lowering (simvastatin 10 mg/day) in 7 healthy middle-aged men with cholesterol levels meeting current recommendations. Flow-mediated brachial artery vasoactivity was measured using 7.5 MHz ultrasound and expressed as percent diameter change from baseline to hyperemic conditions (1 minute following 5 minutes of blood pressure cuff arterial occlusion). Flow-mediated vasoactivity rose from 5.0 +/- 3.6% at baseline to 10.5 +/- 5.6%, 13.3 +/- 4.3%, and 15.7 +/- 4.9% (all p < 0.05) as cholesterol fell from 200 +/- 12 to 161 +/- 18, 169 +/- 16, and 153 +/- 11 mg/dl after 2, 4, and 12 weeks, respectively, of cholesterol-lowering therapy. Vasoactivity and cholesterol returned to baseline levels 12 weeks after simvastatin discontinuation. Overall, vasoactivity was found to correlate inversely with cholesterol levels (r = -0.47, p = 0.004). These data suggest that flow-mediated brachial artery vasoactivity responds rapidly to changes in cholesterol levels and that endothelial function improves by lowering cholesterol levels below recommendations of current guidelines.