Aldrighi José M, Oliveira Rute Loreto S, D'Amico Elbio, Rocha Tania R F, Gebara Otávio E, Rosano Giuseppe M C, Ramires José Antônio F
Heart Institute (InCor), University of São Paulo Medical School, Rua Afonso de Oliveira Santos 50, 3o andar, CEP 05663-030 São Paulo, SP, Brazil.
Gynecol Endocrinol. 2005 May;20(5):249-57. doi: 10.1080/09513590500097549.
The aim of the study was to investigate the impact of the climacterium (before and after menopause) on platelet activation.
Platelet activation has been associated to the risk of cardiovascular disease. There is much speculation about the relationship between platelet function and sex steroids, due to peculiarities of platelet action between the genders, including concerns about the influence of low estradiol status in menopausal women.
By means of a cross-sectional study design, 37 female patients divided into two groups were compared. Group A consisted of ten women, mean age 43.9 years, in the premenopausal period, with normal estrogen levels; and Group B comprised 27 patients, mean age 53.0 years, who had all reached menopause. Platelet activation markers, namely P-selectin and glycoprotein IIb-IIIa complex (GPIIb-IIIa), were evaluated by flow cytometry with monoclonal antibodies. A binding index was calculated for both parameters (percentage of positive platelets x mean fluorescence of positive platelets). Also, thromboxane A2 was quantified by means of its main plasma metabolite, thromboxane B2, by enzyme immunoassay.
P-selectin and GPIIb-IIIa expression results revealed lower platelet activation status after menopause, as there was a decrease in both the percentage of P-selectin+ platelets and of GPIIb-IIIa mean fluorescence of positive platelets, lowering both binding indices. P-selectin binding index differed significantly between Group A (12.3 +/- 3, n = 10) and Group B (6.2 +/- 2.9, n = 27; mean +/- standard deviation (SD), p < 0.001). GPIIb-IIIa binding index also differed significantly between both groups (Group A: 18.8 +/- 2.3, n = 10 vs. Group B: 16.2 +/- 3.1, n = 27; mean +/- SD, p < 0.0018). Plasma concentration of thromboxane B2 was 1.07 +/- 0.5 pg/well before menopause (Group A, n = 10) and 1.9 +/- 4.1 pg/well after menopause (Group B, n = 27), not significantly different (mean +/- SD, baseline x therapy, p = 0.85).
After the menopause, climacteric women--whose estradiol status is low--have a decreased activation platelet status compared with premenopausal women. Nevertheless, further studies on a larger sample are necessary for conclusive data regarding cardiovascular disease.
本研究旨在调查更年期（绝经前后）对血小板活化的影响。
血小板活化与心血管疾病风险相关。由于不同性别血小板作用的特殊性，包括对绝经后女性低雌二醇状态影响的关注，关于血小板功能与性类固醇之间的关系存在诸多推测。
采用横断面研究设计，对37名分为两组的女性患者进行比较。A组由10名绝经前女性组成，平均年龄43.9岁，雌激素水平正常；B组包括27名患者，平均年龄53.0岁，均已绝经。通过使用单克隆抗体的流式细胞术评估血小板活化标志物，即P-选择素和糖蛋白IIb-IIIa复合物（GPIIb-IIIa）。计算两个参数的结合指数（阳性血小板百分比×阳性血小板平均荧光）。此外，通过酶免疫测定法，借助其主要血浆代谢物血栓素B2对血栓素A2进行定量。
P-选择素和GPIIb-IIIa表达结果显示绝经后血小板活化状态较低，因为P-选择素阳性血小板百分比和阳性血小板的GPIIb-IIIa平均荧光均降低，两个结合指数均降低。A组（12.3±3，n = 10）和B组（6.2±2.9，n = 27；平均值±标准差（SD），p < 0.001）之间的P-选择素结合指数差异显著。两组之间的GPIIb-IIIa结合指数也有显著差异（A组：18.8±2.3，n = 10 vs. B组：16.2±3.1，n = 27；平均值±SD，p < 0.0018）。绝经前（A组，n = 10）血浆血栓素B2浓度为1.07±0.5 pg /孔，绝经后（B组= 27）为1.9±4.1 pg /孔，差异无统计学意义（平均值±SD，基线x治疗，p = 0.85）。
绝经后，雌二醇水平低的更年期女性与绝经前女性相比，血小板活化状态降低。然而，需要对更大样本进行进一步研究以获取关于心血管疾病的确切数据。
