Related Experiment Videos
Constantly low HDL-cholesterol concentration relates to endothelial dysfunction and increased in vivo LDL-oxidation
J O Toikka1, M Ahotupa, J S Viikari
1Department of Clinical Physiology, Turku University Central Hospital, Turku, Finland.
Insights
Low high-density lipoprotein cholesterol (HDL-C) is linked to impaired vascular endothelial function and increased oxidative stress in young men. This suggests HDL particles protect against endothelial dysfunction and LDL oxidation, potentially reducing atherosclerosis risk.
Area of Science:
- Cardiovascular Medicine
- Lipid Metabolism
- Endothelial Function
Background:
- Low high-density lipoprotein cholesterol (HDL-C) is a risk factor for atherosclerosis.
- The role of HDL-C in endothelial function and lipoprotein oxidation requires further elucidation.
Purpose of the Study:
- To investigate the impact of low HDL-C on vascular endothelial function and low-density lipoprotein (LDL) oxidation in young men.
- To determine the correlation between HDL-C levels, endothelial function, and LDL oxidation.
Main Methods:
- Prospective classification of young men (n=20) into low or high HDL-C groups.
- Measurement of endothelium-dependent flow-mediated dilation (FMD) of the brachial artery.
- Assessment of in vivo LDL oxidation (ox-LDL) via LDL diene conjugation.
Main Results:
- Endothelial function (FMD) was significantly impaired in the low HDL-C group compared to the high HDL-C group (0.2+/-1.2% vs 5.5+/-3.2%, P<0.001).
- Low HDL-C group exhibited higher levels of ox-LDL compared to the high HDL-C group (22.9+/-4.4 vs 18.0+/-1.8, P=0.01).
- FMD correlated positively with HDL-C and HDL(2)-C, and negatively with ox-LDL (P<0.05 for all).
Conclusions:
- Constantly low HDL-C concentration is associated with endothelial dysfunction and increased oxidative stress in healthy young men.
- HDL particles may play a protective role for the endothelium and inhibit LDL oxidation.
- Findings suggest a mechanism linking low HDL-C to increased atherosclerosis risk.
Abstract:
To test the hypothesis that low HDL-C concentration interferes with vascular endothelial function and lipoprotein oxidation, we measured endothelium-dependent flow mediated dilatation (FMD, %) of the brachial artery in young men (n=20) classified prospectively into two groups on basis of having either low or high HDL-C concentration over the past 2 years. As an estimate of in vivo low-density lipoprotein oxidation (ox-LDL), we measured LDL diene conjugation. FMD was present in the group with high HDL-C concentration, but impaired in the group with low HDL-C (5.5+/-3.2 vs 0.2+/-1.2%, P<0. 001). The group with high HDL-C level had significantly lower levels of ox-LDL compared to low HDL-C group (18.0+/-1.8 vs 22.9+/-4.4, P=0.01). In all subjects, FMD correlated with HDL-C (r=0.59, P=0. 006), HDL(2)-C (r=0.62, P=0.004) and ox-LDL (r=-0.56, P=0.013) but not with HDL(3)-C (r=0.16, P=0.52). We conclude that constantly low HDL-C concentration is related with endothelial dysfunction and increased oxidative stress in healthy young men, consistent with the idea that HDL particles may protect endothelium and inhibit the oxidation of LDL. These findings may offer insight into increased atherosclerosis associated with low HDL-C levels.