AJP - Heart and Circulatory Physiology, Vol 259, Issue 3 766-H771, Copyright © 1990 by American Physiological Society
Diminished responsiveness of human platelets to platelet-activating factor during pregnancy
E. Kornecki and Y. H. Ehrlich
Department of Anatomy and Cell Biology, State University of New York Health Science Center, Brooklyn 11203.
Platelet-activating factor (PAF; PAF-acether) is a phospholipid that is
synthesized and released by a number of inflammatory cells and is a potent
inducer of platelet aggregation and secretion. In the present study we
examined the responsiveness of human platelets to various concentrations of
PAF during pregnancy and postpregnancy. We found that in pregnant
individuals the responses of washed gel-filtered platelets to PAF were
either absent or greatly reduced during the 22nd-30th wk of pregnancy and
returned to normal in the postpartum period. In contrast, the responses of
platelets to various concentrations of ADP were not altered during
pregnancy. We propose that during pregnancy circulating levels of PAF in
the maternal circulation, possibly originating from the fetus, may
desensitize maternal platelet receptors to PAF, resulting in a diminished
or a complete lack of response of platelets, specifically to PAF. These
findings may have important implications for our understanding of the role
of PAF in hemostasis during pregnancy and in embryonic and fetal
development.
