Longitudinal study on activated factors XII and VII levels during normal pregnancy

Levels of activated factor XII (FXIIa) and VII (FVIIa) were determined in 100 women with uneventful pregnancies. Samples were divided into five study intervals: three during pregnancy, one at delivery and one 3 d postpartum.
The median (range) for FXIIa levels were 3.4 ng/ml (1.2–9.1) from 11 to 20 weeks, 4.6 ng/ml (1.4–15.2) from 21 to 30 weeks, 5.4 ng/ml (1.9–14.3) from 31st week to delivery, 5.2 (1.3–11.4) at delivery and 4.3 (1.8–8.5) ng/ml in the postpartum sample. For FVIIa the median and range levels for the five periods were 4.9 (1.7–77.3), 7.2 (2.5–80.4), 11.1 (2.9–90.6), 12.0 (3.1–64.1) and 8.2 (4.0–23.5) ng/ml. Although the increase of FVIIa was higher than that of FXIIa during pregnancy, the overall changes of FXIIa and FVIIa were highly correlated ( P  < 0.0001). At each time period the changes of FVIIa correlated with FVII:C which was not the case with FVII:Ag. These data indicate that during pregnancy both the contact phase and extrinsic pathway are activated.     

Increased lipid peroxidation correlates with platelet activation but not with markers of endothelial cell and blood coagulation activation in patients with antiphospholipid antibodies

Recent studies have shown that patients with antiphospholipid antibodies (aPL) have increased lipid peroxidation. We evaluated the urinary excretion of 11-dehydro thromboxane B2 (11-DH-TXB(2) and isoprostane F(2alpha)III (IPF(2alpha)III), reflecting platelet activation and lipid peroxidation in vivo, and plasma soluble markers of endothelial cell, platelet and blood coagulation activation: soluble vascular cell adhesion molecule-1 (sVCAM-1), P- and E-selectin (sPsel and sEsel), F1 + 2 fragment of prothrombin (F1 + 2), thrombin-antithrombin complexes (TAT) and D-Dimer (DD). We studied 79 patients with aPL (47 with previous thrombosis), 45 healthy volunteers (normal controls, NC), 12 patients with systemic lupus erythematosus (SLE) without aPL and a thrombosis control group (TCG) without thrombophilia (n = 16). Urinary levels (mean, range) of eicosanoids and isoeicosanoids were significantly increased in 39 patients with aPL compared with 25 NC, 11-DH-TXB(2) 164.0 ng/mmol creatinine (9.5-1162.8) versus 43.4 ng/mmol creatinine (4.2-87.6), P < 0.001; IPF(2alpha)III 56.9 pg/mg creatinine (5.5-388.7) versus 27.0 pg/mg creatinine (4.6-87.6), P = 0.03. Both metabolites were significantly correlated (rho = 0.49, P = 0.014), but none correlated with any clinical manifestation or antibody profile. The aPL group presented increased levels of sPsel, sEsel, sVCAM-1, TAT, F1 + 2 and DD, but any soluble marker correlated with IPF2alphaIII. Urinary 11-DH-TXB(2) correlated with sPsel (rho = 0.39, P = 0.04). Compared with SLE controls, the SLE group with aPL had higher levels of F1 + 2. Plasma levels of F1 + 2 and DD were significantly increased and a trend to higher sPsel was found in aPL patients with thrombosis compared with the TCG. Platelet activation, lipid peroxidation and blood coagulation activation seem to be important in the pathophysiology of antiphospholipid syndrome.     

Markers of platelet,endothelial cell and blood coagulation activation in leprosy patients with antiphospholipid antibodies

OBJECTIVE: To evaluate plasma levels of markers of platelet, endothelial cell and blood coagulation activation in leprosy patients with or without antiphospholipid antibodies (aPL) and to compare them to those found in patients with antiphospholipid syndrome (APS). METHODS: 42 patients with leprosy (35 lepromatous and 7 borderline): 29 aPL(+) and 13 aPL(-), as well as 26 healthy subjects as normal controls (NC) and 79 control aPL patients without leprosy (59 with and 20 without APS) were included in the study. Plasma soluble P and E selectin (sPsel and sEsel), and VCAM-1 (sVCAM-1), prothrombin F1 + 2 fragment (F1 + 2), thrombin-antithrombin complexes (TAT) and D dimer (DD) were measured by ELISA. The protein C pathway was assessed by the ProC global test. RESULTS: Leprosy patients with aPL presented increased median levels of sPsel [ng/ml (82.0 vs 36.0, p < 0.001)] and sVCAM-1 [ng/ml (495 vs 335, p < 0.001)] compared to NC, as observed in control aPL patients without leprosy. Levels of sPsel in aPL(+) patients with leprosy were significantly higher than in aPL(-) ones (52.5 ng/ml), p = 0.005. However, plasma markers of thrombin generation were increased in control aPL patients without leprosy but not in those with leprosy. ProcC global test was abnormal in 24.1% of leprosy patients with aPL compared to 4.4% of NC (p < 0.024), and to 57.2% of control patients with aPL without leprosy (p = 0.005). CONCLUSIONS: We demonstrated that although patients with leprosy present a high prevalence of aPL, and platelet and endothelial cell activation in vivo to the same extent than patients with APS, they do not show a procoagulant state.     

Plasma levels of factor XIIa and factor VIIa are increased but not related in primary hyperlipidaemia.

The lipolysis of triglyceride-rich lipoproteins may provide a surface that supports the activation of factor XII (FXII) with subsequent activation of factor VII (FVII). Plasma levels of activated FVII (FVIIa) but not activated FXII (FXIIa) are increased in the post-prandial state when there is a transient increase in triglyceride levels. We compared plasma levels of FXIIa antigen in control subjects (n = 33) and in patients with chronically elevated lipids (primary hyperlipidaemia, n = 49), with FVIIa and markers of thrombin generation. Results are given as median (first and third quartiles). Plasma levels of FXIIa [2.34 (1.68-3.32) ng/ml versus 1.53 (0.93-1.86) ng/ml, P = 0.0002], FVIIa [3.02 (2.15-4.64) ng/ml versus 2.20 (1.66-2.56) ng/ml, P = 0.0004], thrombin-antithrombin complexes [3.08 (2.16-5.54) microg/I versus 2.13 (1.46-2.84) microg/l, P = 0.005] and prothrombin fragment 1 + 2 (Pro F1 + 2) [1.28 (1.08-1.50) nmol/l versus 0.92 (0.65-1.08) nmol/l, P = 0.0001] were increased compared with controls irrespective of the type of hyperlipidaemia. In hyperlipdaemic subjects, levels of Pro F1 + 2 were correlated with FVIIa (r = 0.56, P = 0.0002) and FXIIa (r = 0.31, P = 0.03). These results suggest increased activation of both FVII and FXII in hyperlipidaemic subjects, which correlates with increased thrombin generation. Given the lack of correlation between levels of FXIIa and FVIIa, it remains to be established whether the increase in FXIIa is responsible for increased FVIIa activity in this subject group.     

Inhibition of tissue factor pathway during intermittent pneumatic compression: A possible mechanism for antithrombotic effect

Intermittent pneumatic compression (IPC) devices are an effective prophylaxis against lower extremity deep vein thrombosis. Their antithrombotic effect has been attributed to a reduction in venous stasis and enhanced fibrinolysis. The initiating mechanism for blood coagulation is the tissue factor (TF) dependent pathway, which is inhibited by tissue factor pathway inhibitor (TFPI). We have investigated the effect of IPC on the TF pathway in 6 normal subjects and 6 patients with postthrombotic venous disease undergoing IPC for 120 minutes; all subjects were studied with each of 5 IPC devices. In normal subjects and patients, plasma factor VIIa (FVIIa) activity (the activated form of factor VII [FVII]) declined from mean values ranging 51 to 65 and 50 to 53 mU/mL before IPC with different devices to 10 to 13 and 20 to 22 mU/mL at 180 minutes, respectively (P<0.001 for all groups). FVII antigen levels were unchanged. Plasma TFPI (P<0.001) rose from mean baseline values ranging 69 to 79 and 57 to 61 ng/mL to 76 to 123 and 71 to 79 ng/mL at 180 minutes in normal subjects and patients, respectively (P<0. 001 for all groups). Plasma prothrombin fragment F1.2 levels showed minimal changes. There was an inverse relationship between TFPI and FVIIa in normal subjects (r=-0.31, P=0.001) and patients (r=-0.37, P<0.001). IPC results in an increase in plasma TFPI and decline in FVIIa. Inhibition of TF pathway, the initiating mechanism of blood coagulation, is a possible mechanism for the antithrombotic effect of IPC.     

Clinical features and pregnancy outcome in antiphospholipid syndrome patients with history of severe pregnancy complications

Abstract

Objective. To clarify the clinical significance of antiphospholipid antibody (aPL) profile in patients with obstetric antiphospholipid syndrome (APS).

Methods. Clinical records of 13 pregnant patients (15 pregnancies) with obstetrical APS were reviewed over 10 years. Patients who met the Sapporo Criteria fully were studied, whereas those with only early pregnancy loss were excluded. In addition to classical aPL: lupus anticoagulant (LA), anticardiolipin antibody (aCL), and anti-β2-glycoprotein I (aβ2GPI); phosphatidylserine-dependent anti-prothrombin antibody (aPS/PT) and kininogen-dependent anti-phosphatidylethanolamine antibody (aPE) were also examined in each case.

Results. Cases were divided into two groups according to patient response to standard treatment: good and poor outcome groups. All cases with poor outcome presented LA, with IgG aβ2GPI and IgG aPS/PT were also frequently observed. IgG aPE did not correlate with pregnancy outcome.

Conclusion. aPL profile may predict pregnancy outcome in patients with this subset of obstetric APS.     

Thrombin generation in antiphospholipid syndrome

Our objective was to study acquired Activated Protein C (APC) resistance in patients with antiphospholipid antibodies (aPL) using a thrombin generation based assay. We compared patients with and without lupus (systemic lupus erythematosus, SLE). A parameter summarizing APC inhibition of thrombin generation with increasing APC concentrations (IC(50)-APC) was increased in all patient groups compared to controls: median values were 15.3 (interquartile range, IQR, 9.7 to 34.0) in patients with primary antiphospholipid syndrome (APS), 27.3 (IQR 23.5 to 43.5) in patients with SLE without APS, 64.1 (IQR 25.9 to 65.0) in patients with SLE/APS compared to 10.4 [IQR 8.5 to 15.8] in controls, respectively p = 0.003, p = 0.0001 and p = 0.0001. In conclusion, patients with SLE and primary APS displayed a hypercoagulable state characterized by APC resistance.     

Neonatal effects of maternal antiphospholipid syndrome

Antiphospholipid antibodies (aPL) can impair the physiologic development of a fetus during pregnancy not only by causing thrombosis of the placental vessels, but also by directly binding throphoblast cells and modifying their functions. Consequently, the presence of aPL in pregnant women is linked to an increased rate of pregnancy complications. These include recurrent early miscarriages, late fetal losses, and hypertensive disorders of gestation. In this clinical setting, preeclampsia is usually early and severe and can be complicated by the syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome). The close association between aPL and obstetric pathology supports the inclusion of these manifestations in the clinical classification criteria of antiphospholipid syndrome. About 30% of children born to mothers with aPL passively acquire these autoantibodies; fortunately, the occurrence of thrombosis seems extremely rare in these babies. The prospective ongoing studies of children born to antiphospholipid syndrome patients reassure us about their general good health; however, some data suggest that learning difficulties might occur, possibly related to in utero exposure to aPL.     

Advanced prostate cancer activates coagulation: a controlled study of activation markers of coagulation in ambulatory patients with localized and advanced prostate cancer.

Cancer and increased age are risk factors for coagulation activation. Patients with advanced prostate cancer, which usually presents in the seventh to eighth decade of life, are likely to be at increased risk for thrombosis. We report results of a controlled study of changes in specific and sensitive markers of coagulation activation in patients with prostate cancer. Complete blood count, prothrombin time, partial thromboplastin time, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT) and quantitative D-dimers (DD) were measured in 30 patients of advanced prostate cancer (androgen ablated), in 30 newly diagnosed localized prostate cancer patients, in 30 healthy age-matched volunteers, and in 20 healthy young volunteers. Plasma F1 + 2 (P < 0.05) and DD (P < 0.05), but not TAT, were significantly elevated in healthy elderly males (mean age, 77 years) when compared with healthy young volunteers (mean age, 35 years). F1 + 2, TAT and DD were significantly elevated in advanced prostate cancer when compared with healthy age-matched controls (P < 0.001). In conclusion, advanced prostate cancer patients have significantly increased levels of sensitive markers of coagulation activation compared with healthy age-matched controls. This data can be used to plan studies to determine the risk of clinically significant coagulopathy and the role of primary prophylaxis in patients with advanced prostate cancer.     

Raised plasma adiponectin levels in type 1 diabetic pregnancies

OBJECTIVES: Adiponectin has antidiabetic properties. Our aim was to determine plasma adiponectin levels during pregnancy and postpartum (PP), in women with type 1 diabetic mellitus (T1DM) and nondiabetic (ND) women. PATIENTS AND METHODS: Fasting plasma adiponectin and leptin levels were measured in 20 ND and 19 T1DM women, at 20 and 30 weeks' gestation, and 9 months' PP. Insulin measurements were made in ND women. RESULTS: In both groups, after accounting for body mass index (BMI), leptin levels increased during pregnancy (P < 0.01) and were significantly higher than PP (P < 0.001). However, no significant differences in leptin levels were noted between both groups at any stage (P = 0.46). Conversely, adiponectin levels were higher in T1DM at all stages of the study (P < 0.001). A significant fall in adiponectin levels was seen between 20 and 30 weeks' gestation in both groups (ND: P < 0.001; T1DM: P < 0.05); however, this decrease was attenuated in the T1DM group. Adiponectin levels PP were significantly higher than at 30 weeks (ND: P < 0.001; T1DM: P < 0.001). Furthermore, in T1DM, adiponectin appeared to correlate negatively with leptin, but only reached significance PP (r = -0.46, P < 0.001). In the ND group, adiponectin correlated negatively with both leptin (PP: r = -0.56, P < 0.0001) and insulin (P < 0.005). CONCLUSIONS: Higher adiponectin levels were noted in T1DM throughout gestation compared to ND pregnancies, with no difference in leptin levels. The significance of these findings needs to be determined.     

Incidence of postpartum thrombosis and preterm delivery in women with antiphospholipid antibodies and recurrent pregnancy loss

OBJECTIVE: To determine the frequency of preterm deliveries and postpartum thrombotic events (TE) in pregnancies resulting in live birth in women with antiphospholipid antibodies (aPL) and a history of recurrent pregnancy loss (RPL) but without prior TE. METHODS: We reviewed the pregnancy outcomes of women referred to our clinic with a history of RPL. Prepregnancy investigation of RPL included history of TE and aPL positivity (anticardiolipin IgG and lupus anticoagulant). We recorded use of anticoagulation therapy during and after pregnancy, obstetric outcome, gestational age at delivery, and postpartum course. Included in our study were women with unexplained RPL with no history of TE attending our clinic who subsequently had pregnancies that resulted in a live birth. RESULTS: Over a 5-year period, 260 women with RPL and no history of TE had a live birth at our clinic. Eighty-seven (33.5%) were positive for aPL and 173 (66.5%) were negative for aPL. Twenty-four percent of deliveries in the aPL-positive group occurred before 37 weeks' gestation compared to 9.8% of deliveries in the aPL-negative group (p = 0.004; 95% CI 0.052-0.234). There were no antepartum TE in either group. One woman in the aPL-positive group (1.1%) had a deep vein thrombosis 3.5 weeks postpartum while receiving prophylactic anticoagulant therapy, compared to none in the aPL-negative group. CONCLUSION: A significantly higher proportion of aPL-positive patients had preterm deliveries compared to aPL-negative patients, but pregnancy-related TE was infrequent: 99.0% of aPL-positive women with a history of RPL and no prior TE who had a live birth at our clinic had an uneventful pregnancy, delivery, and postpartum course.     

Lack of association between antiphospholipid antibodies and thrombocytopenia in patients with Wegener's granulomatosis

BACKGROUND AND OBJECTIVE: In patients with Wegener's granulomatosis (WG), thrombocytopenia is less common than thrombocytosis. An increased prevalence of antiphospholipid antibodies (aPL), which is associated with thrombocytopenia, has been noted in patients with WG. The aim of this study was to examine the relationship between thrombocytopenia and aPL in patients with WG. METHODS: Thrombocytopenic episodes were searched for in a random sample of 83 patients with WG. Stored sera obtained during thrombocytopenia, which was defined as platelet count below 130 x 10(9)/L, were examined by 2 different enzyme-linked immunosorbent assays (ELISA) for IgG and IgM anticardiolipin antibodies (aCL) and for IgG antiphosphatidylserine antibodies (aPS). Screening for lupus anticoagulant was performed by use of activated partial thromboplastin time (aPTT). Results were compared with the prevalence of aPL in 20 consecutive nonthrombocytopenic patients with WG. RESULTS: Six cases with thrombocytopenic episodes were found in the group of 83 patients with WG. Increased IgG and IgM aCL were detected in 1 patient, who also had elevated IgG aPS. A positive test result solely for IgM aCL was found in another patient. These findings were consistent in both ELISA for aPL. Five patients were being treated with cyclophosphamide when thrombocytopenia occurred. In the group of nonthrombocytopenic patients with WG, elevated IgG aCL and IgG aPS were consistently detected in 1 patient in both ELISA. Three other patients had positive results in single tests, which were not confirmed by the second assay. In all patients, aPTT was normal. CONCLUSIONS: Thrombocytopenia is a rare finding in patients with WG. A similar prevalence of aPL in thrombocytopenic and nonthrombocytopenic patients with WG provides no evidence that aPL play a major role in the pathogenesis of these events. Thrombocytopenia in WG is more likely caused by the myelotoxic effect of preceding cyclophosphamide treatment. We found a frequency of aPL in WG that exceeds frequencies seen in the general population but does not approximate those detected in systemic lupus erythematosus and closely related disorders. Semin Arthritis Rheum 31:4-11.     

Lipoprotein (a) levels in normal pregnancy and in pregnancy complicated with pre-eclampsia

Lipoprotein (a) (Lp(a)) is recognised as a risk factor for arterial and venous thrombosis, a property which may relate to its structural similarity to plasminogen. Pregnancy is associated with a hypofibrinolytic state. Elevated Lp(a) may influence fibrinolysis and have an unfavourable role in pregnancy outcome. In this study alterations in plasma Lp(a) concentrations during normal pregnancy was examined, in a detailed longitudinal investigation, in ten women together with changes in other lipid parameters. In addition, Lp(a) concentrations were examined in subjects with pre-eclampsia (n=10) relative to matched controls (n=10), since it has recently been reported that a substantial increase in circulating Lp(a) occurs in this disorder. Lp(a) concentration increased steadily in normal pregnancy between 10 and 35 weeks with a doubling of the median value from 14.5 to 27.0 mg/dl (P=0.01). A significant increase in Lp(a) values was observed in all subjects with increasing gestation (median rise 190%, range 117-340%). This increase was intermediate to those seen in plasma triglyceride and cholesterol. No significant difference in Lp(a) values was observed in subjects with pre-eclampsia, compared with matched normal pregnancy controls (median 14 mg/dl [IQR 4.7-69.0] in pre-eclampsia vs 20 mg/dl [9.0-56. 3] in controls; P=0.57), at a median gestation of 32 weeks. In conclusion, there is a 2-fold increase in Lp(a) during normal pregnancy, which may influence fibrinolysis. Circulating Lp(a) is not significantly elevated in women with pre-eclampsia, and thus is unlikely to play a role in the pathophysiology of this disorder.     

Low-density lipoprotein particle diameter in normal pregnancy and preeclampsia

We investigated the changes of low-density lipoprotein (LDL) size and serum lipids during pregnancy and postpartum not only in normal pregnant women but also in preeclampsia. Serum triglyceride (TG) and total cholesterol levels as well as serum high-density lipoprotein (HDL)-cholesterol, apolipoprotein (Apo) A1, B, E and remnant-like particle (RLP)-cholesterol levels were increased in normal pregnant women. The LDL peak particle diameter (PPD) in normal pregnant women was decreased during pregnancy and that at 37 weeks of gestation showed significant decrease compared with the women at 4 weeks after delivery (25.8 +/- 1.0 vs.26.8 +/- 0.7 nm, p < 0.05). The LDL-PPD in the preeclamptic women at admission (mean gestational age: 36 +/- 2.4 weeks) was significantly lower than that in normal pregnancy at 37 weeks of gestation (24.7 +/- 1.2 vs. 25.8 +/- 1.0 nm, p < 0.05). Moreover, the LDL-PPD in the preeclamptic women was significantly higher after delivery compared with the level at admission (27. +/- 0.7 vs. 24.7 +/- 1.2 nm, p < 0.05) accompanied by an improvement in plasma lipids profile. These findings suggest that the predominance of small, dense LDL, a potential contributor to endothelial dysfunction, may be a possible predictor of preeclampsia.     

Maternal-fetal flow,negative events,and preeclampsia: role of ACE I/D polymorphism

The risk for an adverse pregnancy outcome is markedly higher in women with history of preeclampsia. This may stem from impaired placentation in early gestation and from high impedance to flow in uteroplacental circulation. The renin-angiotensin system is one of the mediators of the remodeling of spiral arteries throughout pregnancy. The D allele of the Insertion/Deletion (I/D) polymorphism in the ACE gene has been associated with higher ACE activity, accounting for 47% of the total phenotypic variance of serum enzyme levels. To investigate whether the ACE I/D polymorphism affects maternal uteroplacental and fetal umbilical circulation and the pregnancy outcome in women with a history of preeclampsia, 106 women underwent Doppler examination of uterine arteries resistance index and umbilical artery pulsatility index at the 16th, 20th, and 24th weeks of gestation and were genotyped for the I/D polymorphism. This study found a difference in genotype distribution (P=0.0002) and allele frequency (P<0.0001) between women with and those without preeclampsia recurrence and fetal growth restriction as well as an association (P=0.0007) between DD genotype and risk of recurrent preeclampsia or fetal growth restriction. At the 16th, 20th, and 24th weeks, uterine artery resistance indexes were significantly lower in II, higher in DD, and intermediate in ID genotype carriers, whereas the umbilical artery pulsatility index values were significantly higher in the DD group in comparison to ID and II genotypes. The current study shows that the ACE I/D polymorphism affects uteroplacental and umbilical flows and the recurrence of an adverse pregnancy outcome in women with history of preeclampsia.     

The prevalence of antibodies to anionic phospholipids in patients with the primary antiphospholipid syndrome, systemic lupus erythematosus and their relatives and spouses

OBJECTIVES: Antiphospholipid antibodies (aPL) have been associated with syndromes involving thrombosis, fetal loss and thrombocytopenia. Genetic and environmental conditions are among the factors attributed to the cause of autoimmune diseases such as the antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). The aim of this study was to determine whether these factors determine the prevalence of aPL. METHODS: Three groups of patients were tested for the presence of IgG, IgM and IgA anticardiolipin (aCL), antiphosphatidylinositol (aPI), antiphosphatidylglycerol (aPG) and antiphosphatidylserine (aPS) antibodies: (i) patients with primary APS (PAPS); (ii) patients with SLE and secondary APS; and (iii) patients with SLE without APS. First-degree relatives and spouses of patients with SLE/APS were also tested for circulating aPL. RESULTS: IgG aPL were particularly prevalent in patients with PAPS. IgG aPI and aCL were more prevalent in patients with PAPS than the IgM equivalents (P < 0.0001). Notably, none of the patients with PAPS had IgA aPL. A significantly higher number of relatives of patients with SLE/APS possessed IgG aPL than the normal controls. Except for aPG (P < 0.03), the prevalence of these antibodies in the relatives was not significantly different from patients with SLE/APS. The relatives also had significantly higher prevalence of IgG aPI, aPS and aCL antibodies than IgM aPL antibodies. In contrast, the prevalence of IgG aPL in the spouses was no different than in the healthy controls. CONCLUSIONS: Genetic factors, shared by patients and their relatives, seem to have some effect on the prevalence of aPL in the subjects studied, while environmental factors shared by spouses appear to have no influence.     

Hypercoagulability, high tissue factor and low tissue factor pathway inhibitor levels in severe ovarian hyperstimulation syndrome: possible association with clinical outcome.

During ovarian gonadotrophin stimulation for ovulation induction or in vitro fertilization, a clinical severe ovarian hyperstimulation syndrome (OHSS) may occur. Only few studies have investigated the mechanism responsible for the alterations of the haemostatic system in women affected by severe OHSS. The aim of the present study was to investigate the correlation between the magnitude of ovarian stimulation and the increase in fibrin formation and degradation in severe OHSS. Twenty-five patients (age range 23-43 years) who were hospitalized for severe OHSS, 25 women undergoing in vitro fertilization who did not develop OHSS (case-control group) and 25 healthy age-matched women (healthy control group) were investigated. On the day of admission a number of haemostatic markers, including D-dimer, thrombin-antithrombin complexes (TAT), prothrombin fragment 1 + 2 (F1 + 2), plasmin-antiplasmin complexes (PAP), tissue factor (TF), tissue factor pathway inhibitor (TFPI) and von Willebrand factor antigen (vWF), were examined. In patients with severe OHSS, TF, D-dimer, TAT, F1 + 2, PAP and vWF antigen plasma levels were significantly higher than those observed both in the case-control group and in healthy controls, whereas TFPI levels were significantly lower (P < 0.005) with respect to both case-controls and healthy controls. D-Dimer levels were related with serum oestradiol levels and oocyte number recovered (r = 0.45, P < 0.001 and r = 0.47, P < 0.001, respectively). D-Dimer and TAT levels were significantly (P < 0.05 and P < 0.005, respectively) higher in OHSS patients with unsuccessful pregnancy outcome (D-dimer, 226.5, 56-1449 ng/ml; TAT, 19.8, 3.1-82.6 microg/l) with respect to those with successful outcome of pregnancy (D-dimer, 145, 29-330 ng/ml; TAT, 5.0, 1.0-19.6 microg/l). Our data indicate that a marked hypercoagulability with alterations of TF and TFPI levels is detectable in patients with severe OHSS and that it is related to the clinical outcome.     

Intracellular events in platelet activation induced by antiphospholipid antibodies in the presence of low doses of thrombin

OBJECTIVE: Thrombosis and thrombocytopenia are features of the antiphospholipid syndrome (APS), suggesting that antiphospholipid antibodies (aPL) may bind platelets, causing activation and aggregation of platelets and thrombosis. The intracellular events involved in aPL-mediated platelet activation are not fully understood and are therefore the subject of this study. METHODS: IgG fractions and their F(ab')(2) fragments were purified from the sera of 7 patients with APS and from the pooled sera of 10 healthy subjects (as controls). Phosphorylation of p38 MAPK, ERK-1/2, and [Ca(2+)]-dependent cytosolic phospholipase A(2) (cPLA(2)) was determined in lysates of washed platelets pretreated with low doses of thrombin and aPL or control IgG or their F(ab')(2) fragments, by immunoblot. The effects of aPL on platelet aggregation in the presence or absence of a p38 MAPK inhibitor, SB203580, were examined. Thromboxane B(2) (TXB(2)) production was detected by enzyme-linked immunosorbent assay on gel-filtered platelets treated with aPL and thrombin, with or without SB203580. Calcium mobilization studies were done utilizing a fluorometric assay. RESULTS: Treatment of platelets with IgG aPL, or their F(ab')(2) fragments, in conjunction with subactivating doses of thrombin resulted in a significant increase in phosphorylation of p38 MAPK. Neither the IgG aPL nor their F(ab')(2) fragments increased significantly the phosphorylation of ERK-1/2 MAPKs. Furthermore, pretreatment of platelets with SB203580 completely abrogated the aPL-mediated enhanced aggregation of the platelets. Platelets treated with F(ab')(2) aPL and thrombin produced significantly larger amounts of TXB(2) when compared with controls, and this effect was completely abrogated by treatment with SB203580. In addition, cPLA(2) was also significantly phosphorylated in platelets treated with thrombin and F(ab')(2) aPL. There were no significant changes in intracellular [Ca(2+)] when platelets were treated with aPL and low doses of thrombin. CONCLUSION: The data strongly indicate that aPL in the presence of subactivating doses of thrombin induce the production of TXB(2) mainly through the activation of p38 MAPK and subsequent phosphorylation of cPLA(2). The ERK-1/2 pathway does not seem to be involved in this process, at least in the early stages of aPL-mediated platelet activation.     

Comparison of prothrombin fragment 1 + 2 with thrombin-antithrombin III complex in plasma of patients with disseminated intravascular coagulation.

Plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT) are thought to be specific indicators of thrombin generation. To assess whether these two parameters behave similarly in vivo, we compared the plasma levels of F1 + 2 with TAT in 41 patients with disseminated intravascular coagulation (DIC). Both F1 + 2 and TAT were markedly elevated in patients with DIC compared to healthy subjects. Although a positive correlation was found between F1 + 2 and TAT (r = 0.585, P < 0.001) there was a large scatter among individuals. In addition, plasma concentrations of TAT were much lower than F1 + 2. The correlation between the TAT/F1 + 2 ratio and antithrombin III was weak (r = -0.268, P = 0.09). The TAT/F1 + 2 ratio was positively correlated with TAT (r = 0.481, P = 0.002), indicating that the difference in molar concentrations between F1 + 2 and TAT decreased as the TAT value increased. Serial determinations of these parameters showed that plasma TAT values changed roughly in parallel with F1 + 2 in the majority of patients. Although further studies are required to further clarify the observed differences between F1 + 2 and TAT, both parameters would be equally useful for the precise detection of haemostatic activation in patients with DIC.     

THE MATERNAL OVARY IS NOT THE SOURCE OF CIRCULATING INHIBIN LEVELS DURING HUMAN PREGNANCY

The concentration of immunoreactive inhibin in serum was measured in three pregnant women with premature ovarian failure involved in a donor oocyte in-vitro fertilization programme. Inhibin was not detectable in peripheral serum prior to conception but rose within 2-4 weeks of embryo transfer, whereafter levels rose gradually during pregnancy (less than 20 weeks 1.22 U/ml (0.85-1.76) versus greater than 20 weeks 2.28 U/ml (1.42-3.67), P less than 0.01; geometric mean +/- 67% confidence interval) and were similar to those observed in 24 normal pregnant women. hCG rose in parallel with inhibin during early gestation, but declined after 3 months. FSH levels were elevated before conception and were suppressed during pregnancy. In conclusion (i) immunoreactive inhibin is detectable from early gestation in women with no endogenous ovarian function indicating that the maternal ovary does not contribute significantly to inhibin secretion during pregnancy; (ii) the trophoblast is the likely source of inhibin during pregnancy; (iii) the regulation of hCG and inhibin secretion differs throughout gestation; and (iv) inhibin may have a role in FSH regulation during pregnancy and/or a local role within the feto-placental unit.