The Activation of the Contact Phase of Coagulation by Physiologic Surfaces in Plasma: The Effect of Large Negatively Charged Liposomal Vesicles

• Published in: Blood Vol. 73; no. 6; pp. 1525 - 1533
• Main Authors: Mitropoulos, K.A., Martin, J.C., Reeves, B.E.A., Esnouf, M.P.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01.05.1989; The Americain Society of Hematology
• Subjects: Anions; Biological and medical sciences; Blood Coagulation; Blood coagulation. Blood cells; Cold Temperature; Factor VII - physiology; Fatty Acids - blood; Female; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods, hemostasis, fibrinolysis; Humans; In Vitro Techniques; Liposomes; Molecular and cellular biology; Pregnancy - blood; Surface Properties; Human; Coagulation test; Liposome; Activation; Lipoprotein; Coagulation factor; Contact surface; Blood plasma
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V73.6.1525.1525

The endogenous, negatively charged surface that induces activation of the contact coagulation factors was investigated in plasmas taken from women in late pregnancy and control subjects of child-bearing age. The plasmas from the two groups of subjects were incubated at 4°C for 24 hours either in plastic or in glass tubes and the factor VII coagulant activity (Vllc) was assayed in the treated plasmas. The activation of factor VII under these conditions involves the generation of enzymes derived from factor XII (Xlla). The contact surface is rate-limiting for the activation of factor VII in the plasmas in both groups of subjects and can be supplemented by large multilamellar liposomal vesicles carrying the appropriate density of negative charge. The size of these vesicles is within the range of sizes of the large lipoprotein particles (chylomicrons, very low and intermediate-density lipoproteins). The relationship between the density of negative charge on the liposo-mal vesicles and Vllc was similar in the late pregnancy and the control plasmas incubated in plastic tubes. At a saturating density of negative charge the observed relative Vllc was similar in both sets of plasmas. The incubation of late pregnancy or control plasma in plastic tubes in the presence of sodium stearate caused Vllc to increase with increasing concentration of the added fatty acid. These results suggest that large lipoprotein particles carrying the appropriate free fatty acid at a sufficient density of negative charge could provide the contact surface that induces the generation of factor Xlla and the subsequent activation of factor VII. Moreover, plasmas from women in late pregnancy have a higher concentration of potential surface and a higher density of negative charge than the plasmas from nonpregnant women.