Effect of menopause on platelet activation markers determined by flow cytometry.

Pre-menopausal women have a lower risk of cardiovascular disease compared to post-menopausal women. Cardiovascular disease is more age dependent in women than in men. The association of platelet activation and cardiovascular thrombotic events is well established. Standardized techniques were used to evaluate platelet activation markers by flow cytometry, using 3-color analysis (CD 61PerCP, CD 62P, and PAC-1) in 49 post-menopausal (mean +/- SD age, 56.16 +/- 33.51 years) and 42 pre-menopausal (age, 39.38 +/- 7.07 years) women. Results of our study showed a significant increase in CD 62P in post-menopausal women as compared to the pre-menopausal group (2.66 +/- 4.26% vs. 0.52 +/- 2.71%, P < 0.001). Similarly, PAC-1 was significantly increased in post-menopausal women (21.54 +/- 2.48% vs. 3.70 +/- 2.31%, P < 0.001). Furthermore, there was a significant association of CD 62P with serum estradiol in both groups. PAC-1 was significantly associated with age in both groups. The results suggest the role of platelets in the increased incidence of thrombotic events and disease in post-menopausal women. (c) 2005 Wiley-Liss, Inc.