Avaliação dos níveis de lipoproteína (a) e sua relação com parâmetros hemostáticos em mulheres jovens e na pós-menopausa

Abstract

Lipoprotein (a) is a molecule with composition similar to LDL, an independent risk factor for cardiovascular disease by promoting atherogenesis. It presents structural homology with plasminogen and may contribute to thrombogenesis by reduced fibrinolysis. Atherothrombotic events may be associated with genetic, physiological conditions, smoking, lifestyle, interference of hormones and age. The use of hormones for contraception and hormonal reposition (HRT) therapy may interfere with hemostasis promoting hypercoagulability and consequently adding to the significance of elevated levels of Lp(a). We sought to evaluate the lipid profile, with emphasis on Lp(a) and its relationship with hemostatic parameters in both young and postmenopausal women, in use or not of hormones. We included 82 women distributed into four groups: young women using oral contraceptive (JP/n=20) or not (JN/n=20) and menopausal women under HRT use (MP/n=17) or not (MN/n=25). Total cholesterol (TC), triglycerides, and glucose levels were determined by colorimetric-enzymatic method, while HDL by direct method. LDL and VLDL were determined by using Friedewald equation, while Lp(a), apoA1, apoB and hsCRP by turbidimetry. PAI-1, F1+2 and plasminogen were measured by ELISA and the DiD by ELFA. Statistical analyzes were performed by MINITAB version 15.0 using the Mann- Whitney test for comparing the medians of groups of pairs: JNxJP, MNxMP and JNxMN. Correlations among all variables were calculated by Pearsons correlation. Significant differences were observed for CT concentrations between JN x JP, MN x MP and JN x MN; for HDLc between JN x MN; for LDLc between MN x MP and JN x MN groups. For VLDLc and TG, differences were observed between JN x JP and JN x MN, while for apoAI and apoB between JN x JP and JN x MN groups. For F1 + 2, differences were obtained between JP x JN. For the JN x MN group, all hemostatic markers were different including DiD. For plasminogen, all groups were different, except MN x MP; while for hsCRP, between JN xJP, and between JN x MN groups; and for glucose between JN x MN. For Castelli Index II, significant differences were observed between the MN x MP and JN x MN groups. Strong correlations were observed between the variables F1 + 2 x TG and between F1 + 2 x VLDL in JN group; and between apoB x CT, apoB x LDL in MN group. A joint analysis of data from lipid and hemostatic profiles shows that levels of Lp(a) did not influence the fibrinolytic system performance and they have not been changed due to the use of hormones or age. Based on the same data, one can infer that the use of oral contraceptive seems to be atherogenic and thrombogenic; while the use of HRT seems to protect the process of atherogenesis, but did not significantly influence thrombogenesis. Finally, the advance age factor by itself has contributed significantly to the atherogenic and thrombogenic potential, as expected.