THE ISOLATION OF PREPARATIONS OF THROMBOPLASTIC PROTEIN FROM HUMAN ORGANS

Role of tissue factor in feto-maternal development: a xiphos

In this review, the dual role of tissue factor (TF) in pregnancy is described. On the one hand, TF is required for embryonic and placental development in a successful pregnancy, and on the other hand, pathologic expression of TF can lead to serious pregnancy complications in humans and mice. Human studies show increased TF levels in plasma, amniotic fluid and and/or placentas of abnormal pregnancies affected by miscarriages, preterm birth, or pre-eclampsia. Interestingly, using two mouse models, we found that blood-borne TF plays a crucial role in the pathogenesis of pregnancy complications. TF on neutrophils and monocytes is a critical mediator in trophoblast injury and embryo damage in pregnancy loss induced by antiphospholipid antibodies and in the antibody-independent CBA/J × DBA/2 model of miscarriages. Blockade of TF or genetic diminution prevented pregnancy complications, suggesting that TF may be a good target for therapy in patients with recurrent miscarriages, pregnancy loss, and pre-eclampsia. In addition, statins, which downregulate TF, may constitute a good therapeutic option for women with pregnancy complications. Clinical trials should be conducted to confirm these observations in women.

Tissue factor (coagulation factor III) is present in placental microvilli and cofractionates with microvilli membrane proteins

We have demonstrated that tissue factor is present in preparations of placental microvilli. The similarity of the procoagulant activities of microvilli and placental homogenates indicate that tissue factor is neither deficient nor enriched in microvilli relative to the bulk of placental tissue. On the basis of solubility in Triton X-100 and ammonium sulphate, and its affinity for phenyl-Sepharose, microvilli tissue factor is indistinguishable from that in whole placental homogenates.

Sequential studies in pre-eclampsia using plasma fibrinogen chromatography

The technique of plasma fibrinogen chromatography was used to study sequential changes in coagulant and fibrinolytic activity in six patients with severe pre-eclampsia. Plasma soluble fibrinogen-fibrin complex and plasma fibrinogen-fibrin degradation product levels were measured as indices of coagulant and fibrinolytic activity respectively. Clinical deterioration antenatally was accompanied by increasing coagulant and decreasing fibrinolytic activity, while a more stable clinical picture was associated with steady coagulant and increasing fibrinolytic activity. Following delivery, a surge in fibrinolytic activity accompanied or preceded clinical recovery. The pattern of increased coagulant and diminished fibrinolytic activity would seem to favour the development of disseminated intravascular coagulation in these patients and it is possible that the balance between coagulant and fibrinolytic activity may influence the clinical course and outcome of the pregnancy.

Maternal serum sialomucins during pregnancy and postpartum in patients with pre-eclampsia

The seromucoid fraction of maternal serum glycoproteins is increased in pre-eclampsia and the rise, which is proportional to the severity of the disease, may reflect progressive placental deterioration with increasing trophoblast fragmentation and deportation. The pulmonary lysis of deported trophoblast effects the local release of fetal antigens and thromboplastin in the lungs. The former, which are immunologically inert because they are complexed with maternal serum seromucoid, are released into the peripheral circulation, while the local coagulation hazard presented by the latter is countered by intensified fibrinolytic activity, the products of which are also released into the peripheral circulation. In severe pre-eclampsia the peripheral circulation contains a considerable excess of physically similar proteins derived from the seromucoid fraction and fibrin degradation products, and the conditions which then obtain in the renal glomerulus favour the physical process of coacervation. In that event the mechanism of the origin and development of the renal lesion can be described in purely physical terms.