Inhibition and potentiation of platelet function by lysolecithin
JH Joist, G Dolezel, MP Cucuianu, EE Nishizawa and JF Mustard
The effects of lysolecithin (LPC) on aggregation, serotonin release, shape,
and lysis of rabbit, pig, or human platelets in platelet-rich plasma (PRP)
or Tyrode albumin solution were examined during prolonged incubation. LPC
added to citrated or heparinized PRP from humans or rabbits at a final
concentration above 100 muM caused instantaneous inhibition of platelet
aggregation induced by adenosine diphosphate (ADP), epinephrine (human PRP
only), collagen, or thrombin. The inhibitory effect of LPC was found to be
partially reversible over a period of 60-90 min. LPC at final
concentrations above 30 muM also caused inhibition of ADP-, collagen-, and
thrombin-induced aggregation and collagen- and thrombin-induced release of
serotonin in suspensions of rabbit, pig, or human platelets. With washed
platelets, the inhibitory effect not only rapidly disappeared but was
followed by transient potentiation of aggregation and serotonin release.
This potentiating effect of LPC was most pronounced when thrombin was used
as stimulus. Both inhibition and potentiation were observed at
concentrations of LPC that did not cause a significant change in platelet
shape or loss from platelets of lactic dehydrogenase. Inhibition and
potentiation were also observed when platelets were added to suspending
medium containing LPC, although considerably higher concentrations of LPC
were required under these conditions. Potentiation was not observed when
LPC was added to citrated or heparinized rabbit or human PRP or to washed
rabbit platelets suspended in a medium containing 4% bovine serum albumin.
It seemed likely that some or all of the observed effects of LPC on
platelet function were due to structural modification of the platelet
membrane insufficient to result in gross membrane damage or platelet lysis.
In addition, the results of experiments using 14C-LPC seemed to indicate
that the observed potentiating effect of LPC on platelet function may be
related to its rapid uptake and metabolism by the platelets.
Volume 49,
Issue 1,
pp. 101-112,
01/01/1977
Copyright © 1977 by The American Society of Hematology