α₂‐Antiplasmin and α₂‐Macroglobulin—The main inhibitors of fibrinolysis—During the Menstrual Cycle, Pregnancy, Delivery, and Treatment with oral contraceptives

Abstract

alpha 2-Antiplasmin and alpha 2-macroglobulin have been studied during the menstrual cycle, pregnancy and parturition in healthy women, and during use of various types of contraception in both healthy and diabetic women, and compared with a reference group of healthy men and women. alpha 2-Antiplasmin showed a slight sex difference, with higher values in women. The luteal phase of the menstrual cycle showed slightly higher values than the other phases. alpha 2-Antiplasmin increased during pregnancy, decreased (probably due to consumption) during labor and increased again in the puerperium. Treatment with neither combined contraceptive pills nor low dose progestogen pills gave any changes in alpha 2-antiplasmin. alpha 2-Macroglobulin showed low values during menstruation. The increase during pregnancy and treatment with combined contraceptive pills is in accordance with earlier findings. It is concluded that synthesis and metabolism of alpha 2-antiplasmin are under hormonal influence. The role of alpha 2-antiplasmin in the decreased fibrinolysis in pregnancy is discussed.

Individual Levels of Plasma α2-Antiplasmin and α2 Macroglobulin During the Normal Menstrual Cycle and in Women on Oral Contraceptives Low in Oestrogen

“…In the present study we found no differences in the concentra tions of a2-antiplasmin in the two groups, agreeing well with previous reports on women taking OC containing higher amounts of oestrogen (29,30). However, during the period of OC consumption a slight but statistically significant decrease could be demonstrated.…”

The ADME Characteristics of siRNA Therapeutics and the Opportunity to Predict Disposition in Pregnant Women

“…Humphreys et al showed that a GalNAc-siRNA was bound to human plasma alpha-2-macroglobulin and alpha-thrombin in vitro (Humphreys et al, 2019). Plasma levels of these proteins have been shown to be increased during pregnancy, especially during the third trimester, compared to pre-pregnancy, nonpregnant matched controls and postpartum (Ganrot and Bjerre, 1967;Chandra et al, 1973;Wallmo et al, 1982;Stimson et al, 1983;Bagot et al, 2017). If these proteins are the main binding proteins for GalNAc-siRNA in humans, the PPB of these siRNAs may increase during pregnancy.…”

Postoperative Adhesion Development Following Cesarean and Open Intra-Abdominal Gynecological Operations

“…The anticoagulant activity is expressed through the selective inactivation of FV(activated)a and FVIIIa 131 (Figure 4). In addition, estrogen-induced increase in α2-antiplasmin and α2-macroglobulin 132,133 has been observed during pregnancy. Thus, the overall fibrinolytic activity is impaired during pregnancy and may not return completely to normal for 6 to 8 weeks after delivery.…”