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DOI: 10.1055/s-0038-1657866
Inhibition of Platelet Aggregation by Human Placenta
Publikationsverlauf
Received 15. Februar 1985
Accepted 06. Mai 1985
Publikationsdatum:
18. Juli 2018 (online)
![](https://www.thieme-connect.de/media/10.1055-s-00035024/198502/lookinside/thumbnails/10-1055-s-0038-1657866-1.jpg)
Summary
Human placental cytosol inhibits platelet aggregation induced by high doses of collagen. The aim of this study was to investigate whether this anti-aggregating activity was caused only by the presence of various activities already described in the placenta (an ADP-consuming enzyme, a fatty acid cyclooxygenase inhibitor, and a thromboxane synthetase inhibitor) or whether another factor was present.
Heating the cytosol at 50° C for 6 min destroyed the inhibitor of collagen-induced aggregation. ADPase and the AA pathway inhibitors were not modified by this treatment. We therefore show the presence of an additional anti-aggregating factor: it is destroyed by heating at 50° C.
We also tested for the presence of an inhibitor of AA release in the placental cytosol using three different methods (rabbit platelets in PRP, washed rabbit platelets, and NRK fibroblasts) but no inhibition could be evidenced.
We conclude that this new anti-aggregating factor, which is probably a protein, acts neither through AA release inhibition nor AA cascade inhibition.
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References
- 1 Myatt L, Elder MG. Inhibition of platelet aggregation by a placental substance with prostacyclin-like activity. Nature 1977; 268: 159-160
- 2 Hutton RA, Chow FPR, Craft IL, Dandona P. Inhibition of platelet aggregation in the feto-placental unit and myometrium with particular reference to the ADP-degrading property of placenta. Placenta 1980; 1: 125-130
- 3 Dembélé-Duchesne MJ, Thaler-Dao H, Chavis C, Crastes de PauletA. Some new prospects in the mechanism of control of arachidonate metabolism in human placenta and amnion. Prostaglandins 1981; 22: 979-1002
- 4 Dembélé-Duchesne MJ, Thaler-Dao H, Chavis C, Crastes de PauletA. The human placental anti-aggregating factor is neither prostacyclin, nor a prostacyclin metabolite. Prostaglandins 1982; 24: 701-714
- 5 Barradas MA, Craft IL, Dandona P, Jeremy JY. Does the human placenta produce prostacyclin?. J Physiol 1983; 336: 77P
- 6 Lewis GP, Watts IS. Prostaglandin endoperoxides, thromboxane A2 and adenosine diphosphate in collagen-induced aggregation of rabbit platelets. Br J Pharmacol 1982; 75: 623-631
- 7 Harrowing PD, Williams KI. Homogenates of rat placenta contain a factor(s) which inhibits uterine arachidonic acid metabolism. Br J Pharmacol 1979; 67: 482-483
- 8 Duchesne MJ, Thaler-Dao H, Crastes de PauletA. Prostaglandin synthesis in human placenta and fetal membranes. Prostaglandins 1978; 15: 19-42
- 9 Aster RH, Jandl JH. Platelet sequestration in man. I. Methods. J Lab Clin Invest 1964; 43: 843-855
- 10 Chignard M, Le Couedic JP, Vargaftig BB, Benveniste J. Platelet-activating factor (PAF-acether) secretion from platelets: effect of aggregating agents. Br J Haematol 1980; 46: 455-464
- 11 Holmsen H, Holmsen I, Bernardsen A. Microdetermination of adenosine diphosphate and adenosine triphosphate in plasma with the firefly luciferase system. Anal Biochem 1966; 17: 456-473
- 12 Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin-phenol reagent. J Biol Chem 1951; 193: 265-275
- 13 De Larco JE, Todaro GJ. Epithelioid and fibroblastic rat kidney cell clones: epidermal growth factor (EGF) receptors and the effect of mouse sarcoma virus transformation. J Cell Physiol 1978; 94: 335-342
- 14 Saeed SA, McDonald-Gibson WJ, Cuthbert J, Copas JL, Schneider C, Gardiner PJ, Butt NM, Collier HOJ. Endogenous inhibitor of PG synthetase. Nature 1977; 270: 32-36
- 15 Brennecke SP, Humphreys J, Turnbull AC, Mitchell MD. Assay of plasma endogenous inhibitor(s) of PG synthetase using an enzyme incubation-radioimmunoassay method. Prostaglandins, Leucotrienes Med 1982; 8: 615-634
- 16 Saeed SA, Strickland DM, Young DC, Dang A, Mitchell MD. Inhibition of prostaglandin synthesis by human amniotic fluid obtained during labor. J Clin Endocrinol Metab 1982; 55: 801-803
- 17 Harrowing PD, Williams KI. Influence of blood elements on arachidonic acid metabolism in the pregnant uterus. In: Prostacyclin in pregnancy. Lewis PJ, Moncada S, O’Grady J. (Eds). Raven Press; New York: 165-1982
- 18 Shemesh M, Hansel W, Strauss III JF. Modulation of bovine placental prostaglandin synthesis by an endogenous inhibitor. Endocrinology 1984; 115: 1401-1405
- 19 Blatt WF, Dravid A, Michaels AS, Nelson L. Solute polarization and cake formation in membrane ultrafiltration: causes, consequences, and control techniques. In: Membrane Science and Technology. Flinn JE. (Ed). 47-97 Plenum Press; New York: 1970
- 20 Kinlough-Rathbone RL, Packham MA, Reimers HJ, Cazenave JP, Mustard JF. Mechanisms of platelet shape change, aggregation, and release induced by collagen, thrombin, or A23187. J Lab Clin Med 1977; 90: 707-719