Platelets of female mice are intrinsically more sensitive to agonists than are platelets of males.
OBJECTIVE
It has been reported that women fare worse after ischemic coronary events, but the mechanisms remain unclear. Because platelets play a central role in the formation of occlusive thrombi at sites of ruptured atherosclerotic plaques, we studied male/female paired mouse littermates for sex differences in platelet function.


RESULTS
We compared platelet reactivity in male/female mouse littermates by monitoring agonist-induced fibrinogen (FGN) binding and platelet aggregation. Compared with the platelets from males, platelets from females bound more FGN in response to low concentrations of thrombin and collagen-related peptide. Female platelets also demonstrated greater aggregation in response to adenosine diphosphate and collagen-related peptide. Platelet protein tyrosine phosphorylation on activation also showed small differences between sexes. These differences are independent of platelet size and surface expression of alphaIIbbeta3 and GPIb-IX-V, and they were not blocked by apyrase or aspirin. The sex differences we observed were intrinsic to platelets, because they were observed in washed platelets, but not when platelets were in plasma.


CONCLUSIONS
The platelets of female mice were more reactive than those of males in a manner independent of COX-1 and secreted ADP.
Leng
Xing-Hong
XH
Medicine/Thrombosis Research, Baylor College of Medicine, Houston, TX 77030, USA.
Hong
Song Yun
SY
Larrucea
Susana
S
Zhang
Wei
W
Li
Tong-Tong
TT
López
José A
JA
Bray
Paul F
PF
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002352:Carrier Proteins / Q000494:pharmacology; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides; D010949:Plasma / Q000502:physiology; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D010974:Platelet Aggregation / Q000502:physiology; D012727:Sex Characteristics; D015398:Signal Transduction / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology
D002352:Carrier Proteins; D010455:Peptides; C435908:collagen-related peptide; D005340:Fibrinogen; D013917:Thrombin