Procoagulant activity and cellular origin of microparticles in human amniotic fluid.
BACKGROUND
Amniotic fluid contains various procoagulant factors involved in intro-vascular amniotic fluid-induced coagulopathies. During the progression of normal pregnancy, microparticles would be shed off from cells and accumulate in amniotic fluid over time. In this study, our aims were to investigate the cellular origin and procoagulant entity of these microparticles.


METHODS
Twenty amniotic fluid samples from healthy parturient women were collected, and the microparticles were isolated and stained with phycoerythrin-labeled antibodies to CD138, CD41a, CD144 and CD11b to identify their cellular origin. Their phosphatidylserine and tissue factor expression levels were quantified with fluorescein isothiocyanate-labeled annexin V and anti-tissue factor antibody staining. Their procoagulant activity was tested with plasma coagulation assay and factor Xase and prothrombinase assays.


RESULTS
Phenotypic analysis showed 36.8% and 33.8% of amniotic fluid microparticles positive for CD138 and CD11b, respectively, indicating their epithelial cell or leukocyte origin. Of these microparticles, 66.3±5.9% expressed phosphatidylserine while 37.4±4.1% expressed tissue factor. In addition, amniotic fluid microparticles could significantly shorten the plasma coagulation time and increase the production of factor Xa and thrombin. Inhibition assays with annexin V and anti-tissue factor antibody confirmed the coagulation effects of amniotic fluid microparticles.


CONCLUSIONS
The microparticles derived from epithelial and leukocytes may be a mechanism of amniotic fluid-induced coagulopathies.
Department of Hematology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China.
Shuchuan
S
Liu
Department of Cardiology, the Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001, China.
Li
L
Wei
Department of Hematology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China.
Yan
Y
Zhang
Department of Hematology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China.
Mengyuan
M
Xu
Department of Hematology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China.
Chen
C
Wang
Department of Hematology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, China. Electronic address: zhouj1956@163.com.
Jin
J
Zhou
D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry*; D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests / Q000379:methods*; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D005260:Female; D006801:Humans; D011247:Pregnancy; D055815:Young Adult
Amniotic fluid microparticles; Phosphatidylserine; Procoagulant activity; Tissue factor