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

Abstract

SummaryDeterminations of α2-antiplasmin and α2-macroglobulin were made in plasma samples collected during one normal or hormone induced cycle in 15 normal women and 11 women using oral contraceptives containing 30 μg ethinyl oestradiol and 150 pg levo-norgestrel. The immediate plasmin inhibition test for determination of α2-antiplasmin was modified for application on a centrifugal analyser using the chromogenic peptide substrate Chromozym PL®. α2-Macroglobulin concentration was determined by radial-immunodiffusion. There were no differences between the two groups in the mean concentrations of α2- antiplasmin and α2-macroglobulin, but during the cycle a slight, and statistically significant fall occurred in the α2-antiplasmin concentration in both groups, while the fluctuations of α2- macroglobulin were small and insignificant. Distinctly individual levels of both inhibitors were found to exist. The variations in these during the periods of the cycle fluctuated within a much narrower range than the variation of the total average. The results stress the importance of determining the fluctuations in individual levels in longitudinal studies. These findings exclude variations in the concentrations of these inhibitors as possible sources of a change in the antithrombotic potential caused by oral contraceptives.

Appropriate Milieu for the Assay of Alpha-2-Antiplasmin Activity with Chromogenic Substrates

“…This results in a deviation of the observed inhibition reference curve from the theoreti cal curve, especially in the area of low ct2-antiplasmin values. In practice, this inter feres with the automation of the ci2-antiplasmin assay, as recently reported [6], and the interpretation of low values of ct2-antiplasmin. The comparison of purified a 2-antiplasmin with a 2-antiplasmin in plasma is com plicated as well.…”

“…This supports the above data that free plasmin activity is recorded properly with the precautions mentioned and it emphasizes that the origin of the anomaly must be searched for in the properties of the amidolytic substrate. Jespersen and Sidelmann [6] also reported a difference between S-2251 and chromozym PL.…”

Haemostatic variables during normal menstrual cycle

“…Two studies found cyclic variation of D-dimer, two studies of PAI-I, two studies of uPA and one study of tPA. We found one study about α2-antiplasmin, in which the lowest levels were reported during late follicular phase (27). Therefore, we assume that most fibrinolytic parameters have no significant cyclic variation during the menstrual cycle.…”

“…Koh et al (14) found the lowest levels late follicular (cd 10-14) whereas Giardina et al (12) found the lowest D-dimer levels in luteal phase (cd 28). Additionally, we found one study by Jespersen et al (27), which described a longitudinal study about α2-antiplasmin during the menstrual cycle. They found significantly lower levels during the late follicular phase (cd 12-16).…”

“…We found 13 longitudinal (7, 11-14, 18, 20, 22-27) and two cross-sectional studies (28,29). Twelve studies determined the cyclic variation of PAI-I, tPA and/ or uPA (11-14, 18, 20, 22-26, 28), five studies assessed the cyclic variation of D-dimer (7,12,14,26,29) and one study determined α2-antiplasmin levels during the menstrual cycle (27).…”