Postmenopausal hormone replacement therapy increases plasmatic thromboxane β2

Rute Loreto S Oliveira, José M. Aldrighi, Otávio E. Gebara, Tania R F Rocha, Élbio D'Amico, Giuseppe M C Rosano, José Antônio F Ramires

Research output: Contribution to journalArticlepeer-review


Objective: This study shows the effect of hormone replacement therapy (HRT), using oral estrogen exclusively or in combination with progestin, on platelet activation in healthy menopaused women. Background: Recent evidence from studies of postmenopausal HRT in healthy women demonstrated a short-time increased risk of coronary heart disease. Platelet activation, which generates vasoconstrictory thromboxane A2 (TxA2), has been related to the risk of cardiovascular diseases. Methods: By means of a placebo-controlled study twenty-seven postmenopausal patients were continuously orally administered estrogen in combination with progestin or estrogen exclusively for an 8-week period. Platelet activation was evaluated by flow cytometric P-selectin expression and by enzyme immunoassay plasmatic TxA 2 (TxB2) concentrations. Results: P-selectin binding index changed from 6.3±3.6 to 7.0±3 in the placebo group (n=10); from 5.9+2.2 to 7.9±3.3 in the E+P group (n=8) and from 6.4+2.7 to 7.1±1.9 in the E group (n=9). Plasma concentrations of TxB2 before and after intervention, changed from 1.2+1.2 to 1.5+1.4 (pg/well) in the placebo group; significantly (p=0.005) in the E+P group (n=8), from 0.9+0.3 to 6.1+6.5 (pg/well), and from 1.3+1.5 to 0.8+0.4 (pg/well) in the E group (n=8; mean+standard deviation, basal x therapy, p

Original languageEnglish
Pages (from-to)449-454
Number of pages6
JournalInternational Journal of Cardiology
Issue number3
Publication statusPublished - Mar 30 2005


  • HRT
  • Menopause
  • P-selectin
  • Platelet activation
  • Thromboxane
  • Women

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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