Abstract

BERG, Gabriela et al. Endothelial injuring factors and subendothelial events in healthy postmenopausal women. Acta bioquím. clín. latinoam. [online]. 2007, vol.41, n.4, pp.499-510. ISSN 0325-2957.

In postmenopausal women (PMW), high concentrations of atherogenic apoB lipoproteins is an important component of the multifactorial mechanism underlying a higher risk of coronary artery disease, as compared with premenopausal women (PreMW). Lipoprotein pattern, including apopoproteins A-I and B, LDL chemical composition and small dense LDL (sdLDL), hepatic lipase activity, circulating cholesterol transfer protein and LDL oxidability were assessed in PMW (n=30) in comparison to PreMW (n=28). The following endothelial injuring factors were measured: homocysteine, lipoprotein binding phospholipase A2 (LpPLA2), ferritin, hs-CRP and fibronectin coming from extracellular vascular matrix. Insulin-resistance was evaluated by waist circumference, HOMA and triglyceride/HDL-cholesterol. PMW showed higher apoB/apoA-I (p<0.0001) and a higher proportion of sdLDL which showed significant correlations with the increase in hepatic lipase activity (p<0.005) and insulin-resistance markers (p<0.05). LpPLA2 (p<0.05), homocysteine (p<0.005), hs-CRP (p<0.005), fibronectin (p<0.05) and ferritin (p<0.0001) were elevated in PMW. LDL oxidability showed no differences between groups, but was positively correlated with waist (p<0.02), homocysteine (p<0.05), fibronectin (p<0.05), hs-CRP (p<0.04), LpPLA2 (p<0.05) and sdLDL (p<0.01). After adjusting by age, menopausal condition and waist, LDL oxidability remained associated with homocysteine (b: 0,36) p<0,038), sdLDL (b: 0.36, p=0.027), waist (b: 0.35, p=0.047) and fibronectin (b: 0,41 p=0.05). In this study, the interaction of classic and emerging atherogenic risk factors would suggest a sequence of events starting with endothelial damage caused by homocysteine and sdLDL, promoting its passage into the subendothelial space where it is oxidatively modified, enhanced by homocysteine. The above mentioned inflammatory process takes place with an increase in circulating hs-CRP and ferritin. LpPLA2, coming from macrophages, passes through the endothelium bound to modified LDL, promoting a release of fibronectin from the subendothelial extracellular matrix. Results suggest that the close interaction among endothelial injury, inflammation and insulin resistance can be observed since subclinical atherosclerosis states in healthy PMW.

Keywords : Menopause; Low density lipoprotein oxidability; Fibronectin; Phospholipase A2; Homocysteine; Hepatic lipase.

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