Vesiculation of platelets during in vitro aging
AP Bode, SM Orton, MJ Frye and BJ Udis
Department of Clinical Pathology and Diagnostic Medicine, East Carolina
University School of Medicine, Greenville, NC 27858.
Membranous microparticles (MP) appearing in the supernatant plasma of
stored platelet concentrates (PC) were analyzed by flow cytometry. Two
populations of MP were arbitrarily delineated by light scatter as larger or
smaller than 0.5 micron fluorescent beads. An estimate of MP concentration
was obtained by adding a known amount of fluorescent beads to each sample
before analysis of a set number of counts on the flow cytometer. The
addition of platelet activation inhibitors (prostaglandin E-1,
theophylline, and aprotinin) to the anticoagulant during preparation of PC
combined with a reduction in surface area of the storage container caused
approximately a 40% reduction in the number of MP appearing during storage
relative to donor-matched controls. In addition, the inhibited concentrates
had 84% less platelet factor 3 (PF3) activity in the supernatant and 61%
less released lactic dehydrogenase. A reduction in surface area of the
container in the controls partially offset these differences. A significant
correlation was found (rs = .748) between PF3 levels and the concentration
of larger MP. The inhibitors did not reduce the small number of MP found in
stored platelet-poor plasma. Surface antigen analysis showed that the
majority of MP in PC were platelet-derived; most were positive for
glycoprotein (GP) IIbIIIa (73%) and/or for GPIb (43% to 46%). We conclude
that procoagulant MP are released from platelets during storage as a result
of platelet activation augmented by interaction of platelets with the bag
wall.
Volume 77,
Issue 4,
pp. 887-895,
02/15/1991
Copyright © 1991 by The American Society of Hematology
