title: The formation of platelet-leukocyte aggregates varies during the menstrual cycle.
abstract: Platelet-leukocyte aggregates are considered to play a significant role in blood coagulation and inflammatory processes. We hypothesized that hormonal changes during the menstrual cycle affect the formation of heterotypic aggregates and therefore may constitute cycle-dependent variations of the susceptibility for thromboembolic events and inflammatory disease. We therefore measured platelet-leukocyte interaction by the determination of platelet-leukocyte aggregates (PLA), platelet P-Selectin expression, and platelet fibrinogen receptor activation by PAC-1 binding in 20 healthy women during their menstrual cycle by flow cytometry. The number of platelet-granulocyte aggregates (PGA) and platelet-monocyte aggregates (PMA) was higher at ovulation compared to any other time-point of the menstrual cycle (p = 0.005, p = 0.022, respectively). Likewise, P-Selectin expression peaked on day 14 (p = 0.040). The course of PLA formation during the menstrual cycle followed the course of estrogen levels, strongly suggesting direct effects of estrogen on platelet-leukocyte interaction. The susceptibility to form platelet-leukocyte aggregates that are inducible in vitro by a suboptimal concentration of thrombin receptor activating peptide-6 decreased slightly during the transition from day 1 to 14 (p = 0.040). These data indicate that platelet function varies during particular phases of the normal menstrual cycle.
authors.affiliation: Clinic for Blood Group Serology, Medical University Vienna, Vienna, Austria.
authors.forename: Christiane
authors.initials: C
authors.lastname: Rosin
authors.forename: Markus
authors.initials: M
authors.lastname: Brunner
authors.forename: Stephan
authors.initials: S
authors.lastname: Lehr
authors.forename: Peter
authors.initials: P
authors.lastname: Quehenberger
authors.forename: Simon
authors.initials: S
authors.lastname: Panzer
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000166:cytology / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D054641:Dual Specificity Phosphatase 2; D004967:Estrogens / Q000032:analysis; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000502:physiology*; D008597:Menstrual Cycle / Q000502:physiology*; D019007:P-Selectin / Q000096:biosynthesis; D015539:Platelet Activation / Q000502:physiology; D010974:Platelet Aggregation / Q000502:physiology*; D010976:Platelet Count; D054648:Protein Phosphatase 2; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D039341:Receptors, Fibrinogen / Q000378:metabolism; D012016:Reference Values
chemical_list: D004967:Estrogens; D019007:P-Selectin; D039341:Receptors, Fibrinogen; D005340:Fibrinogen; D054648:Protein Phosphatase 2; C517032:DUSP2 protein, human; D054641:Dual Specificity Phosphatase 2; D017027:Protein Tyrosine Phosphatases