Antibodies against platelet-activating factor and platelet-activating factor-like lipids are raised in women with primary recurrent abortion.

OBJECTIVE: The purpose of this study was to determine the antibody levels against platelet-activating factor (PAF), PAF-like lipids lysophosphatidylcholine (LPC), cardiolipin (CL), and oxidized low-density lipoprotein (LDL) in recurrent abortion. STUDY DESIGN: Eigthy-five women with a history of at least 3 recurrent spontaneous abortions (55 women with primary abortion [31.4+/-5.1 years old]; 30 women with secondary abortion [33+/-4.5 years old]) were compared with 48 age-matched control subjects (33+/-4.4 years old) who had delivered without complications. Antibodies were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: Antibodies against PAF and antibodies against oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (oxPAPC) were raised significantly in the group with primary abortion, as compared to control subjects (P<.05) and not significantly higher than in secondary abortion; antibodies against oxidized LDL, LPC, or CL levels did not differ between groups. CONCLUSION: Antibodies against platelet-activating factor and antibodies against platelet-activating factor-like lipid oxPAPC are associated with primary recurrent abortion and may function as novel disease markers. Whether these antibodies also are pathogenic (eg, by interacting with endothelial cells in placenta or by interfering with platelet-activating factor during embryonal development) remains to be shown.

Measurement of activated protein C resistance during menstrual cycle in women with and without the Leiden mutation.

Variations in the APC ratio during the menstrual cycle were assessed in 25 women without the Leiden mutation, and 10 women who were carrier of the mutation. Blood samples were collected at four occasions during one menstrual cycle. APC ratios were measured with two APTT based plasma methods with and without factor V depleted plasma. None of the methods were able to accurately discriminate between mutated and non mutated women in all samples. Although a normalized method with factor V depleted plasma was favorable. The levels of estradiol and progesterone did not differ between mutated and non mutated women. Our findings suggest that the level of estradiol at estimated time of ovulation is of importance for the response to APC during luteal phase, since the women exhibiting the highest levels of estradiol at time for ovulation had the lowest response to APC.

Primary habitual abortions are associated with high frequency of factor V Leiden mutation.

OBJECTIVE: To analyze the prevalence of the mutation G1691A in factor V gene (Leiden mutation), of mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, and of polymorphism in G20210A in the prothrombin gene in women with recurrent abortions; further, to identify a subgroup at higher risk of being carriers of these mutations. DESIGN: Prospective case control evaluation. SETTING: University clinic. PATIENT(S): Eighty-four women with 3 or more consecutive miscarriages were compared with 69 controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Polymerase chain reactions were performed to identify the mutations G1691A in factor V and C677T in MTHFR genes and the polymorphism G20210A in the prothrombin gene. RESULT(S): In women with primary habitual abortions, 27.8% carried the Leiden mutation. No difference was observed in the prevalence of mutation C677T in the MTHFR gene or in polymorphism G20210A in the prothrombin gene. CONCLUSION(S): The Leiden mutation may play a considerable role for women having primary recurrent abortions.

Decrease in protein C inhibitor activity and acquired APC resistance during normal pregnancy.

BACKGROUND: Since protein C inhibitor (PCI) inhibits activated protein C (APC) and a number of proteases, one would expect lower concentrations of PCI in a hypercoagulable state due to increased consumption of the inhibitor. Normal pregnancy is associated with a state of activated hemostasis, where response to APC is depressed. We aimed to study whether PCI function varies during normal pregnancy, and assess the relationship between this inhibitor and acquired APC resistance. METHODS: PCI activity in plasma was tested during pregnancy and postpartum in 28 healthy pregnant women without factor V Leiden Arg(506) - Gln mutation and in 14 non-pregnant female controls. The PCI levels determined in the present study was compared to the APC ratio (APC-r), we investigated previously, in the same samples. RESULTS: The levels of PCI in the pregnant group, as compared to that in the control group (4.74 +/- 0.48), gradually decreased from the first to the third trimester, i.e., 3.30 +/- 1.31 microg/mL in week 12 (p < 0.001), 2.66 +/- 1.44 microg/mL in week 20 (p < 0.001), 1.92 +/- 1.18 microg/mL in week 28 (p < 0.001), 1.30 +/- 0.94 microg/mL in week 32 (p < 0.001) and 1.49 +/- 1.12 microg/mL in week 37 (p < 0.001). After delivery, they rose to 5.02 +/- 1.93 microg/mL, similar to that in the controls (p > 0.05). The values of APC-r showed the same tendency during gestation and postpartum. CONCLUSION: With advance of normal pregnancy, decreasing PCI function corresponds to increasing APC resistance, probably due to that activated hemostasis acts as a link connecting the two variables.

Response to activated protein C during normal menstrual cycle and ovarian stimulation.

Oestrogen has been pointed out as a pre-thrombotic factor. Protein C is a key enzyme in the down-regulation of blood coagulation. Recent data suggest that activated protein C (APC) resistance which is not due to the factor V:Q 506 Leiden mutation and appears to be acquired, is also a risk factor for thrombosis. In this study, we evaluated the endogenous oestradiol production and its possible influence on APC. Eighteen normally menstruating women were studied during one ovulatory cycle. Furthermore, 20 women undergoing controlled ovarian stimulation, and achieving extremely high oestradiol concentrations, were investigated. Normalized APC (nAPC) ratio (clotting time of tested sample/clotting time of pooled control plasma) was measured. Samples collected on menstrual cycle days 1-3, 6-8, 13-14, 20-24 corresponded to nAPC ratios 1.02 +/- 0.19 (mean +/- SD), 1.05 +/- 0. 15, 1.02 +/- 0.16 and 1.03 +/- 0.21 respectively. During ovarian stimulation, the nAPC ratios were 0.99 +/- 0.12, 1.03 +/- 0.18, 1.01 +/- 0.16 and 0.97 +/- 0.13 at oestradiol minimum, days 5-8 pre-oocyte retrieval, oestradiol maximum and at oocyte retrieval respectively. In spite of the great difference in the concentrations of oestradiol between women in normal menstrual cycle and women undergoing ovarian stimulation, no difference in nAPC ratios was observed.

Reactivity against phospholipids during pregnancy.

Antibodies against phospholipids (PLa) are often thought to be associated with the development of activated protein C (APC) resistance. In the present study, PLa were followed throughout 29 healthy pregnancies and compared to APC resistance. The level of PLa did not change during pregnancy [6.9 +/- 3.7 GPL week 12 versus 6.3 +/- 2.8 GPL week 37; 3.3 +/- 1.8 MPL versus 3.2 +/- 1.5 MPL; and lupus anticoagulant (LA) coefficient 0.99 +/- 0.11 versus 0.94 +/- 0.09], in contrast to the APC resistance, which was suppressed (0.96 +/- 0.22 versus 0.78 +/- 0.13, P < 0.05), but both parameters elevated after delivery (up to 8.7 +/- 4.2 GPL; 1.13 +/- 0.1 LA coefficient; 1.11 +/- 0.22 nAPC ratio; P < 0.05). Three women possessed PLa (1 CLa IgG +/- IgM; 1 IgG CLa +/- PSa +/- PEa; 1 PSa), no LA activity was registered. In the PLa-positive women, dynamics of the nAPC ratio during pregnancy was not related to PLa.

Variability of the response to activated protein C during normal pregnancy.

The response to activated protein C (APC) was investigated in 28 healthy women, non-carriers of the Arg506-Gln mutation in factor V, throughout pregnancy (gestation weeks 12, 20, 28, 32 and 37) and after the delivery. A suppression of APC response was observed which reached lowest values by week 28 (nAPC-ratio 0.78 +/- 0.13), sustained low up to the end of pregnancy and rose after delivery (1.11 +/- 0.22; P < 0.05). APC resistance (nAPC ratio < 0.75) was registered in 16 of the 28 women (57%). A reduction of APC ratio was directly related to its value in the non-pregnant state, being most pronounced in the women with the highest APC ratio. Factor VIII increased during pregnancy and correlated inversely to APC ratio (Z coefficient = -0.645, P < 0.0001). The correlation became weaker in the course of pregnancy, losing significance by week 32. This was explained by the differences in profiles of the two variables: the lowest measured APC ratio preceded the peak of factor VIII in most cases. The most pronounced rise of factor VIII was found in the women with minimal levels of APC ratio between 0.8 and 0.7. These results allowed us to speculate that APC response is closely regulated during pregnancy, aiming to maintain a certain relevant level. Transitory reduction of APC response is connected to factor VIII and discussed as a prevalent mechanism of functional APC resistance during pregnancy.