Small low-density lipoprotein particles and endothelium-dependent vasodilation in postmenopausal women

• Published in: Atherosclerosis Vol. 177; no. 2; pp. 329 - 336
• Main Authors: Wakatsuki, Akihiko, Ikenoue, Nobuo, Shinohara, Koichi, Watanabe, Kazushi, Fukaya, Takao
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ireland Ltd 01-12-2004; Elsevier
• Subjects: Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Blood. Blood coagulation. Reticuloendothelial system; Cardiology. Vascular system; Endothelium; Endothelium, Vascular - physiology; Female; Fundamental and applied biological sciences. Psychology; General aspects; Humans; Hypertriglyceridemia - blood; LDL; Medical sciences; Middle Aged; Oxidation; Oxidation-Reduction; Particle Size; Pharmacology. Drug treatments; Postmenopausal women; Postmenopause - physiology; Vasodilation - physiology; Vertebrates: cardiovascular system; Particle size; Postmenopausal women; Oxidation; LDL; Endothelium; Antianginal agent; Coronary vasodilator agent; Menopause; Estrogen; Lipids; Cardiovascular disease; Hyperlipoproteinemia; Enzymopathy; Lipoprotein a; Vasodilation; Vascular disease; Lipoprotein LDL; Particle; Vasomotricity; Nitroglycerin; Organic nitrate; Atherosclerosis; Dyslipemia; Human; Brachial artery; Metabolic diseases; Triglyceride; Ovarian hormone; Phenotype; Hypertriglyceridemia; Sex steroid hormone; Comparative study
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2004.07.005

Low concentrations of estrogen may decrease endothelial function in postmenopausal women. Elevated plasma triglycerides after menopause are frequently associated with a small, dense low-density lipoprotein (LDL) phenotype. Small LDL particles that are more susceptible to oxidation can also inhibit endothelium-dependent vasodilation. The purpose of the present study was to investigate whether hypertriglyceridemia-induced small LDL particles are associated with endothelial dysfunction in postmenopausal women. We studied 15 premenopausal and 41 postmenopausal women. Postmenopausal subjects were divided into those with LDL subclass pattern A (large particles) and those with pattern B (small particles). Plasma lipids, hormones, and diameter and oxidative susceptibility of LDL were measured. Vasodilatory responses of the brachial artery were evaluated by measuring flow-mediated vasodilation (FMD) and nitroglycerin-induced vasodilation (NID). FMD in both postmenopausal groups was significantly lower than in premenopausal women. FMD in subjects with pattern B was significantly smaller than in those with pattern A (4.9 ± 1.9% versus 8.8 ± 3.6%). NID did not differ significantly among the groups. Plasma triglyceride concentrations were higher, lag time for LDL oxidation was shortened, and LDL-derived thiobarbituric acid-reactive substance (TBARS) concentrations were significantly greater in subjects with pattern B than in premenopausal or pattern A subjects. LDL diameter correlated negatively with plasma triglycerides (
r = −0.51) or LDL-derived TBARS (
r = −0.44) and positively with LDL-lag time (
r = 0.66). FMD correlated negatively with LDL-derived TBARS (
r = −0.36) and positively with LDL diameter (
r = 0.44) or LDL-lag time (
r = 0.43). Vascular endothelial dysfunction may be associated with elevated triglyceride-induced small LDL particles that have enhanced oxidative susceptibility in postmenopausal women.