Intrauterine transfusion for rhesus alloimmunization elevates fetal beta2-microglobulin levels

BACKGROUND

Intrauterine transfusions for rhesus alloimmunization leads to alterations in circulating T-cell populations. Given that elevations in circulating beta2-microglobulin are a marker of T-cell-mediated organ transplant rejection, we evaluated the effect of intrauterine transfusion on fetal beta2-microglobulin levels.

METHODS

Umbilical venous samples were obtained immediately prior to initial transfusion in ten anemic fetuses and in 12 fetuses with prior transfusions. Samples were also obtained from 18 gestational age-matched non-anemic fetuses and eight healthy neonates.

RESULTS

The median concentration of beta2-microglobulin was significantly higher in fetuses with prior transfusions compared with non-anemic controls. In non-anemic controls, and in transfused fetuses, beta2-microglobulin levels decreased throughout gestation (r = -0.69, p = 0.01; and r = -0.80, p = 0.01, respectively). Among anemic and transfused fetuses, beta2-microglobulin levels displayed a negative correlation with fetal hematocrit (r = -0.62, p < 0.05; and r = -0.58, p = 0.04, respectively).

CONCLUSIONS

We conclude that intrauterine transfusion for fetal anemia is associated with increased beta2-microglobulin levels, suggesting immunomodulatory effects of intrauterine transfusion on host immune responses to donor leukocyte antigens.

Thrombin-enhanced matrix metalloproteinase-1 expression: a mechanism linking placental abruption with premature rupture of the membranes

OBJECTIVE

Given the strong clinical association between the decidual hemorrhage of placental abruption and subsequent preterm premature rupture of the membranes, we assessed the effects of thrombin on the expression of the potent interstitial collagenase, matrix metalloproteinase-1 (MMP-1), in cultured endometrial stromal and decidual cells.

STUDY DESIGN

Stromal cells derived from predecidualized cycling endometrium and decidual cells from term decidua were cultured in a defined medium containing estradiol, to mimic the hormonal milieu of the non-pregnant proliferative phase, or estradiol plus medroxyprogesterone acetate (MPA), to mimic the hormonal milieu of pregnancy, in the presence and absence of thrombin. Culture media were examined for MMP-1 protein levels and cell lysates were examined for steady-state MMP-1 mRNA levels.

RESULTS

MPA strongly inhibited MMP-1 levels in endometrial stromal and term decidual cells. However, thrombin overcame this suppression, producing MMP-1 levels that were several-fold higher than control levels.

CONCLUSION

Extrapolation of thrombin-enhanced MMP-1 expression in cultured endometrial stromal and decidual cells to the in vivo pregnant state provides an explanation for the strong association between placental abruption and preterm membrane rupture.

Plasma levels of thrombin-antithrombin complexes predict preterm premature rupture of the fetal membranes

OBJECTIVE

Decidual hemorrhage (abruption) is strongly associated with preterm premature rupture of fetal membranes (PPROM). Moreover, thrombin enhances decidual matrix metalloproteinase (MMP) expression, and MMP has been strongly linked to PPROM. The current study sought to determine whether increased thrombin activation, as assessed by circulating maternal plasma thrombin-antithrombin (TAT) complexes, predicted subsequent PPROM.

STUDY DESIGN

We conducted a nested, case-control study of plasma TAT levels, measured by sensitive immunoassay, among 27 women with a singleton preterm birth preceded by PPROM and 54 matched, term controls. Receiver operating characteristic curve analysis was performed to identify the optimal TAT cut-off level predicting PPROM.

RESULTS

Mean gestational age at delivery in cases was 33.3 weeks, compared to 39.7 weeks in controls (p < 0.001). Compared with controls, women with PPROM had increased median plasma TAT levels in both the second trimester (5.1 microg/l (range 2.2-26.3 microg/l) vs. 3.2 microg/l (range 1.3-7.3 microg/l); p = 0.001) and third trimester (7.0 microg/l (range 2.6-85.8 microg/dl) vs. 4.8 microg/l (range 1.7-15.4 microg/dl); p = 0.01). In the PPROM group, 16.0% of the women exhibited bleeding during the pregnancy, while the corresponding value among controls was 3.6% (p = 0.07). In the second trimester, the odds ratio for PPROM with a TAT level of > 3.9 microg/l was 6.0 (95% CI 1.67-21.1). This value predicted PPROM with a sensitivity of 88%, specificity of 68% and positive and negative predictive values of 82% and 97%, respectively.

CONCLUSION

Second-trimester elevated plasma TAT concentrations are predictive of subsequent PPROM. These data provide further evidence that PPROM is associated with decidual thrombin activation.

Decidual cell-expressed tissue factor maintains hemostasis in human endometrium

We showed that decidualized stromal cells of luteal phase and pregnant human endometrium express tissue factor (TF), the primary initiator of hemostasis, thereby suggesting a mechanism by which perivascular decidual cells can mitigate the risk of hemorrhage during endovascular trophoblast invasion. Progestins enhanced TF mRNA and protein levels in monolayers of human endometrial stromal cells (HESCs), with estradiol (E2) + progestin, further enhancing TF levels despite a lack of response to E2 alone. This differential ovarian steroid response has been found for several decidualization markers. Further studies with cultured HESCs established that elevated TF levels are mediated by the progesterone receptor and are maintained for weeks in response to E2 plus progestin, thus simulating the chronic upregulation of TF levels observed in decidualized HESCs in vivo. Recent studies revealed that elevated TF expression during in vitro decidualization of HESCs involved both the EGFR and progesterone receptor. Thus, enhancement of TF mRNA and protein levels in the HESCs required co-incubation with a progestin (MPA) and an EGFR agonist such as EGF or TGF-alpha. In correspondence with co-elevation of EGFR and TF in decidualized HESCs in sections of luteal phase and pregnant endometrium, EGFR levels proved to be progestin-enhanced in the cultured HESCs. We established that progestin-enhanced TF expression in HESCs was trancriptionally regulated, then evaluated the relative roles of SP and EGR-1 sites on the TF promoter in regulating this expression. Transient transfections with a series of promoter constructs containing overlapping SP and EGR-1 sites and with constructs in which the EGR-1 and SP sites were systematically inactivated by site-directed mutagenesis established the dominance of SP sites in both basal and progestin-enhanced TF transcriptional activity. Additional experiments involving transient transfections with SPloverexpressing vectors and with a specific blocker of if Sp1 binding to its corresponding GC box specified the importance of the Sp1 transcription factor. These results were further validated by immunostaining, which revealed that the ratio of Sp1 to Sp3 increased during progestin-regulated decidualization of HESCs in vitro and in vivo. The absence of canonical estrogen and progesterone response elements from either the TF or Sp1 gene promoters suggests that the EGFR may help to mediate progestin-enhanced TF expression during decidualization of HESCs.

Risk stratification and pathological mechanisms in preterm delivery

The delivery of infants before 37 weeks gestation is a leading cause of perinatal mortality and morbidity in the United States. Traditional methods of predicting women at risk relying on obstetric history or premonitory symptoms (detected clinically or by tocodynamometry) are neither sensitive nor specific. Recent approaches to predicting preterm delivery have included sonographic measurement of cervical length and various biochemical assays. Although more sensitive than traditional methods, none of these alone exhibits sufficient accuracy to warrant widespread use. We contend that the failure of current approaches to predicting preterm delivery reflects an inadequate understanding of the underlying pathogenesis. Clinical and experimental evidence support the concept that most cases of preterm delivery reflect four pathogenic processes, which share a common final biological pathway leading to uterine contractions and cervical changes with or without premature rupture of membranes. These pathogeneses are: (1) activation of the maternal or fetal hypothalamic-pituitary-adrenal axis; (2) decidual-chorioamniotic or systemic inflammation; (3) decidual haemorrhage (i.e. abruption); and (4) pathological distention of the uterus. Our research seeks to combine the most useful biophysical and biochemical markers of such processes with optimal clinical and epidemiological predictors into a composite, easily applied risk tool. This integrated approach has the potential to identify at-risk asymptomatic patients with high sensitivity, specificity, and positive and negative predictive values, and also to ascertain underlying pathogenic processes that can lead to targeted therapy. To accomplish these goals, we employ logistic regression and artificial neural network models to assess and apply the appropriate weight to markers associated with each of the above pathogenic pathways, in addition to markers of the final common pathway leading to fetal membrane rupture, cervical extracellular matrix degradation, and myometrial activation. By combining these markers, we expect ultimately to produce a predictive model that is more robust than any existing method, and that identifies the relative contribution of each pathogenic process. Further analysis of this model using a neural network will enable us to identify asymptomatic patients destined to deliver preterm with high sensitivity, specificity, positive and negative predictive values, and to assess the relative contribution of each of the four distinct pathogeneses to this preterm delivery risk.

Regulation of plasminogen activator inhibitor 1 expression by interaction of epidermal growth factor with progestin during decidualization of human endometrial stromal cells

OBJECTIVE

During human pregnancy implantation, trophoblasts invade maternal blood vessels in a process that risks hemorrhage. Previous studies have demonstrated enhanced expression of type 1 plasminogen activator inhibitor, the primary inhibitor of fibrinolysis, during progestin-induced decidualization of estradiol-primed human endometrial stromal cells in vivo and in vitro. Decidual cell-expressed plasminogen activator inhibitor 1 is appropriately positioned to avert implantational hemorrhage. Because of the absence of estrogen or progesterone response elements from the plasminogen activator inhibitor 1 gene promoter, I posited that epidermal growth factor mediates these steroid effects and that expression of epidermal growth factor receptor in human endometrial stromal cells is under ovarian steroid control.

STUDY DESIGN

Confluent human endometrial stromal cells were exposed to vehicle control or to either estradiol (10(-8) mol/L) or medroxyprogesterone acetate (10(-7) mol/L), or both, with or without growth factors. After 40 hours the cultures were analyzed for plasminogen activator inhibitor 1 protein and messenger ribonucleic acid expressions. Immunostaining for epidermal growth factor receptor was carried out in sections of cycling and gestational endometrial tissues.

RESULTS

In the absence of steroids, epidermal growth factor did not alter plasminogen activator inhibitor 1 expression. In the absence of epidermal growth factor, estradiol and medroxyprogesterone acetate enhanced human endometrial stromal cell-secreted plasminogen activator inhibitor 1 protein levels 8-fold (n = 12; P <.001), whereas estradiol alone had no effect. Marked synergistic increases in plasminogen activator inhibitor 1 levels were elicited when epidermal growth factor was added with estradiol and medroxyprogesterone acetate (n = 12; 65-fold; P <.0001). Both transforming growth factor alpha and epidermal growth factor, which act through epidermal growth factor receptor, increased steady-state plasminogen activator inhibitor 1 messenger ribonucleic acid levels several-fold when added with estradiol and medroxyprogesterone acetate. In contrast, transforming growth factor beta, which does not activate epidermal growth factor receptor, did not elevate plasminogen activator inhibitor 1 messenger ribonucleic acid or protein levels whether added alone or with estradiol and medroxyprogesterone acetate. In correspondence with these in vitro observations, immunostaining for epidermal growth factor receptor was increased in human endometrial stromal cells undergoing decidualization in sections of secretory phase and first-trimester endometrial tissue.

CONCLUSIONS

Taken together, these in vitro and in vivo results indicate that both epidermal growth factor and progesterone receptors are required for maximal plasminogen activator inhibitor 1 expression by human endometrial stromal cells.

Minimally invasive endoscopy in the treatment of preterm premature rupture of membranes by application of fibrin sealant

We report only the 3rd case of closure of amniorrhexis following genetic amniocentesis. Our technique is the first to use endoscopic visualization of the rupture site and apply maternal platelets and fibrinogen/thrombin (Hemaseel Haemacure Corp Sarasota F1). The patient underwent repair at 20.6 weeks, 26 days after spontaneous rupture of membranes post-amniocentesis. At the time of the procedure the amniotic fluid index was 1 cm. Patient was delivered at 32.3 weeks secondary to complications of diabetes and severe preeclampsia. The neonate had APGARS of 7 at 1 min and 8 at 5 min and was discharged home on Day 21 of life.

Biological mechanisms underlying the clinical effects of mifepristone (RU 486) on the endometrium

The abortifacient and menstrual effects of the potent antiprogestin, RU 486 (mifepriston) are associated with both endometrial hemorrhage and extracellular matrix (ECM) degradation. Such processes reflect reduced perivascular decidual cell hemostatic and increased ECM-degrading protease activity. In this review, we summarize the effects of RU 486 on different proteases involved in these processes and expressed by in vitro decidualized endometrium stromal cells. The expression of tissue factor (TF), the primary initiator of hemostasis; urokinase-type plasminogen activator (uPA); tissue-type plasminogen activator (tPA); plasminogen activator inhibitor-1 (PAI-1) as well as the potent matrix metalloprotease, MMP-3 was assessed. These endpoints of decidualization are regulated by progesterone. It was observed, that RU 486 blocks and reverses progestin-enhanced stromal cell TF protein and mRNA expression and PAI-1 protein and mRNA expression, whereas blocks and reverses progestin-inhibited stromal cell uPA, tPA and MMP-3 protein and mRNA expression. These coordinate enhancement of plasminogen activator and MMP-3 expression promotes proteolysis of the decidual ECM, which leads to endometrial sloughing during menstruation. Moreover, destabilization of endometrial microvessels resulting from degradation of their surrounding ECM is consistent with the heavy bleeding after RU 486 administration. On the other hand, with blocking the expression of TF and PAI-1, RU 486 creates a haemorrhagic and fibrinolytic milieu around the endometrial vessels, suggesting a mechanism for RU 486-induced endometrial hemorrhage. The steroid antagonist RU 486 (mifepristone) causes menstrual bleeding when given during the luteal phase of the menstrual cycle (1) and induces abortion in 64-85% of pregnant patients when administered before the 50. postmenstrual days (2, 3). These clinical actions are thought to reflect the antiprogestational effects of RU 486. Pathologic studies showed, that the effects of RU 486 on primate and human luteal phase endometrium include reduced stromal edema, increased venular diameter. Erythrocyte and leukocyte diapedesis, focal hemorrhage, degeneration of the stromal extracellular matrix, and eventual disruption of the superficial layer of the endometrium (4, 5). This antihormone acts at the receptor level and possibly also at the postreceptor level(s) (6). The most important mechanism of action is to compete with progesterone at the level of their respective binding site in the ligand binding domain of the progesterone receptors. The binding of RU 486 to the receptor leads to conformational changes in the DNA-binding site of the progesterone-receptor (7). As a consequnce of these changes, the interaction between the receptor and the progesterone-response elements in the promoter region of progesterone-responsive genes is altered (7). The menorrhagic and abortifacient properties of RU 486 are associated with the induction of endometrial hemorrhage. The physiological mechanisms by which human endometrium permits menstrual hemorrhage in the absence of pregnancy yet maintains hemostasis during endovascular trophoblast invasion (avoiding early abortion) has been investigated in our laboratory by evaluating endometrial expression of different proteins that play role in the process of hemostasis. Besides the endometrial haemostasis, we also examined the proteolytic processes leading extracellular matrix (ECM) degradation, which is also an integral part of menstruation. In this review we sought to summarize the biological mechanisms underlying the clinical effects of RU 486 on endometrial haemorrhage/haemostasis and on ECM degradation.

Effects of norplant on endometrial tissue factor expression and blood vessel structure

Abnormal uterine bleeding after Norplant administration is primarily responsible for the high discontinuation rate of this safe and effective long-acting implantable progestin-only contraceptive agent. Although tissue factor (TF) is the primary initiator of hemostasis, previous studies indicated that Norplant-associated bleeding persists despite relatively high TF levels in the stromal compartment. Recently, we determined that progestin-enhanced TF expression during decidualization of human endometrial stromal cells involves both the epidermal growth factor receptor and progesterone receptor (PR]. The current study evaluated TF levels in endometrial bleeding (BL) and nonbleeding (NBL) sites obtained by camera-guided hysteroscopy during Norplant contraception. After 1 yr of therapy, immunohistochemical TF levels were unexpectedly higher at BL than at NBL sites. Use of immunohistochemistry and Western blotting indicated that both sites displayed elevated epidermal growth factor receptor levels and that the BL sites exhibited high levels of the PR, as well as the PR(A) and the PR(B) isoforms. Microscopic examination of 1-yr biopsies revealed that significantly larger numbers of enlarged, distended vessels were present in BL, compared with NBL sites. Elevated TF levels and abnormally enlarged blood vessels in the BL sites are consistent with the recently discovered angiogenic role of TF. By promoting aberrant angiogenesis, chronic endometrial overexpression of TF could produce fragile vessels, which are at increased risk to bleed. Analysis of endometrial BL and NBL sites, during Norplant contraception, offers the potential of elucidating local mechanisms that control enhanced TF expression, leading to abnormal angiogenesis at specific endometrial sites.

von Willebrand disease and pregnancy

von Willebrand Disease (vWD) affects approximately 1% of Americans and as many as 25% of women referred for evaluation of menorrhagia. We briefly review the history of vWD, its molecular defects, and diagnostic criteria for each subtype of disease. We also address obstetric management of the patient with vWD. While there is a significant increased risk for postpartum hemorrhage, patients with vWD should not be discouraged to undertake pregnancy.

Expression of angiopoietin-2 by human endometrial endothelial cells: regulation by hypoxia and inflammation

The functional endometrial layer receives the implanting blastocyst, but is sloughed off during menstruation. Angiogenesis regulates growth and repair of cycling human endometrium. While vascular endothelial growth factor initiates angiogenesis, the angiopoietins (Angs) acting via the Tie2 receptor, are key regulators of subsequent angiogenic steps. This study is the first to localize Ang-2 and Tie2 in human endometrium and to study Ang-2 regulation in cultured human endometrial endothelial cells (HEECs). Immunohistochemistry revealed that expression of Ang-2 and Tie2 was absent from the glands, low in stromal cells, and intense in the endothelial cells. In contrast, only weak expression of Ang-1 was detected. The phase of the menstrual cycle did not appear to affect the expression of Ang-2 or Tie2. In vitro studies were carried out utilizing isolated HEECs, the most relevant model for endometrial microvascular biology studies. Both hypoxia and phorbol-myristate-acetate enhanced Ang-2 mRNA levels in HEECs. These results suggest that Ang-2 plays a role in endometrial pathologies complicated by impaired blood flow and inflammation.

The role of tissue factor in regulating endometrial haemostasis: implications for progestin-only contraception

Abnormal uterine bleeding accounts for the unacceptably high discontinuation rate of progestin-only contraceptives. Previously, we found that in-vivo and in-vitro decidualization of human endometrial stromal cells was associated with elevated concentrations of tissue factor (TF), the primary initiator of haemostasis. Moreover, enhanced TF expression required progesterone receptor (PR) and epidermal growth factor receptor (EGFR) mediation. In the current study, endometrial biopsies were sampled from bleeding (BL) and non-bleeding (NBL) sites under camera-directed hysteroscopic guidance after Depo-provera injections. When compared with control biopsies, immunohistochemical examination revealed that 3 months of Depo-provera contraception reduced TF concentrations at the BL sites. However, there were ample EGFR and PR concentrations at BL and NBL sites. Moreover, there was a trend towards the appearance of pathologically enlarged blood vessels at the BL sites. The use of Western blotting revealed that after 3 months of Depo-provera, concentrations of both PRB and PRA isoforms were lower at BL versus NBL sites with decreased PRA concentrations attaining statistical significance. Separate sampling of endometrial BL and NBL sites as shown here for Depo-provera contraception could prove particularly useful in identifying local factors that determine the onset of bleeding during the more protracted time-course of Norplant contraception.

Cell type-specific regulation of fetal fibronectin expression in amnion: conservation of glucocorticoid responsiveness in human and nonhuman primates

The appearance of oncofetal fibronectin (FFN) in cervical and vaginal secretions is predictive of human labor. Levels of FFN in amnion increase with the onset of labor in rhesus monkeys. Since glucocorticoid (GC) levels in serum and amniotic fluid increase in association with parturition, we compared GC-mediated regulation of FFN expression in cultures of amnion epithelial cells and fibroblasts isolated from human and baboon amnions. Cells were maintained with and without dexamethasone (DEX), and levels of FFN in the conditioned media were determined by ELISA. We observed that DEX treatment suppressed FFN levels in both human and baboon amnion epithelial cells, whereas it increased FFN levels in amnion fibroblasts. DEX treatment reduced FFN levels in cytotrophoblasts from human placenta and increased FFN levels in placental fibroblasts. Northern blots revealed that DEX reduced levels of fibronectin (FN) mRNA in amnion epithelial cells and cytotrophoblasts, whereas it increased FN mRNA in amnion and placental fibroblasts. We conclude that GC differentially regulates FFN expression in epithelial and mesenchymal cells from amnion and placenta. In addition, this pattern of cell type-specific FFN regulation by GC is conserved in human and nonhuman primates and may be responsible for parturition-dependent changes in FFN expression in gestational tissues.

Human endometrial endothelial cells: isolation, characterization, and inflammatory-mediated expression of tissue factor and type 1 plasminogen activator inhibitor

Binding of Ulex europaeus lectin to microvessels was used to isolate endothelial cells from cycling human endometrium. Cultured human endometrial endothelial cells (HEECs) exhibited endothelial cell-specific characteristics such as tube formation on a basement membrane matrix and sequestration of acetylated low-density lipoprotein. Markers for potentially contaminating epithelial, stromal, smooth muscle, and bone marrow-derived cells were not detected in the HEEC cultures. Basal and proinflammatory-stimulated immunostaining profiles for endothelial cell-specific adhesion markers, as exemplified by Von Willebrand's factor and E-selectin, were similar for cultured HEECs and human umbilical venous cord endothelial cells (HUVECs). However, HUVECs expressed several extracellular matrix proteins that were absent from cultured HEECs. In the latter, the protein kinase C agonist phorbol myristate acetate transiently enhanced tissue factor (TF) mRNA levels and elicited a more prolonged elevation in TF protein levels, but did not affect plasminogen activator inhibitor-1 (PAI-1) mRNA and protein levels. Inappropriate expression of TF, which initiates hemostasis by generating thrombin, and of PAI-1, which regulates hemostasis by acting as the primary inhibitor of fibrinolysis, can each lead to thrombosis. The differential regulation of TF and PAI-1 expression revealed in the current study emphasizes the importance of using HEECs to evaluate mechanisms regulating the hemostatic/thrombotic balance in human endometrium.

Regulation of tissue factor gene expression in human endometrium by transcription factors Sp1 and Sp3

Prior studies indicate that tissue factor (TF), the primary cellular initiator of hemostasis, is persistently up-regulated in human endometrial stromal cells (HESCs) undergoing progestin-induced decidualization in vivo and in vitro. The mechanism underlying progestin enhancement of TF mRNA and protein levels in these cells involves transcriptional activation of the TF gene. Transient transfections of HESCs with the truncated TF promoters driving the luciferase reporter gene have demonstrated that the region spanning -111 to +14 bp retained differential progestin-enhancing effects. We now demonstrate that RU486 displays inhibitory effects on the progestin-induced TF promoter activity, confirming the involvement of the progesterone receptor. Since the TF minimal promoter (pTF 111 spanning -111 to +14 bp) contains three overlapping Sp1 and three Egr-1 sites, the present study determined whether Sp1 and/or Egr-1 were required for progestin-regulated TF expression. The results indicate that the three Sp1 sites are primarily responsible for both the constitutive and progestational activity of the pTF 111 promoter, whereas the Egr-1 sites have only a minor involvement in both activities. Overexpression of the Sp1 protein resulted in greater than a 6-fold induction in TF promoter activity. In contrast, no enhancement was observed when the Sp3 protein was overexpressed. The concomitant overexpression of Sp1 and Sp3 demonstrated that Sp3 completely blocked the induction of TF promoter activity by Sp1. Moreover, the addition of 10 nM mithramycin, a concentration that inhibits Sp1 binding to target DNA, blocked the progestational induction of TF mRNA expression. Immunohistochemical studies demonstrated increased Sp1 levels in perivascular stromal cells in secretory phase compared with proliferative phase endometria. In contrast, Sp3 expression was greatly decreased in stromal cells of secretory, compared with proliferative phase tissues. The levels of Egr-1 were low in both proliferative and secretory endometria. Immunocytochemistry of E2 vs. E2 + medroxyprogesterone acetate-treated HESCs demonstrated a dramatic reduction in Sp3 expression after progestin treatment, and Northern blots demonstrated progestational increases in Sp1 and reduction in Sp3 mRNA expression compared with controls. Taken together, our results demonstrate that progestin enhancement of TF gene expression in HESCs is mediated principally by Sp1. We propose that progestins regulate HESC TF gene expression in vivo by altering the ratio of Sp1 to Sp3 nuclear factors.

Progestin-epidermal growth factor regulation of tissue factor expression during decidualization of human endometrial stromal cells

Perivascular decidualized human endometrial stromal cells (HESCs) are ideally positioned to prevent peri-implantational hemorrhage during endovascular trophoblast invasion by expressing tissue factor (TF), the primary cellular mediator of hemostasis. Earlier in vivo and in vitro studies have demonstrated enhanced TF expression in estradiol (E2)-primed HESCs during progestin-induced decidualization. However, the absence of estrogen or progesterone response elements from the TF gene promoter suggests that paracrine factor(s) may mediate these effects. We now demonstrate that significant elevation of TF messenger RNA and protein levels in the cultured HESCs require incubation with both epidermal growth factor (EGF) and the progestin medroxyprogesterone acetate (MPA) added, with or without E2. By contrast, no effects were elicited by adding EGF with E2, or by the separate additions of EGF, MPA, or E2 plus MPA. Our finding, that transforming growth factor-alpha, but not transforming growth factor-beta or interleukin 1-beta mimics these EGF effects, indicates that progestin-enhanced TF expression in cultured HESCs requires activation of the EGF receptor (EGFR). Western blot analysis indicated that MPA increased EGFR levels 2-to 3-fold in cultured HESCs. The current results suggest that the progestin up-regulation of TF levels in decidualized HESCs is mediated by enhanced EGFR expression.

Plasma apolipoprotein A-I and B concentrations in growth-retarded fetuses: a link between low birth weight and adult atherosclerosis

Apolipoprotein B is elevated in growth-retarded compared with normally grown fetuses, demonstrating a link between low birth weight and risk of subsequent atherosclerosis. Increased apolipoprotein B levels and an elevated apolipoprotein B to A-I ratio are predictors of atherogenesis. Elevated apolipoprotein B levels in young adults have been linked to atherosclerosis in later life, whereas impaired fetal growth has been linked to higher than normal apolipoprotein B levels in adulthood. We conducted this research to test the hypothesis that circulating apolipoprotein A-I and B concentrations differ in growth-retarded compared with normal fetuses. Fetal umbilical plasma samples were obtained at diagnostic cordocenteses in 18 growth-retarded and 23 normally grown fetuses. Levels of apolipoprotein A-I and B were measured by turbidimetric assay. There were no differences in median (range) plasma apolipoprotein A-I concentrations between growth-retarded and normal fetuses [0.61 (0.30-1.42) vs. 0.60 (0.30-1.63) g/L, respectively; P = 0.94]. In contrast, we found significantly higher plasma apolipoprotein B levels in growth-retarded vs. normal fetuses [0.62 (0.37-1.84) vs. 0.40 (0.16-1.47) g/L, respectively; P<0.001]. Moreover, the ratio of apolipoprotein B to A-I was significantly higher in growth-retarded than in normal fetuses [1.00 (0.38-2.42) vs. 0.53 (0.31-1.80); P = 0.005]. Levels of apolipoprotein B are elevated in growth-retarded fetuses, suggesting a linkage between low birth weight and adult-onset atherosclerosis.

Heritable coagulopathies in pregnancy

Heritable coagulopathies are leading causes of maternal thromboembolism and are associated with an increased risk of maternal and perinatal morbidity and mortality. The most common of these disorders are antithrombin III deficiency, protein C deficiency, protein S deficiency, activated protein C resistance resulting from the factor V Leiden mutation, elevated prothrombin activity associated with a mutation in the prothrombin gene, and hyperhomocystinemia. The maternal risk of a thromboembolic episode is increased by a factor of eight in the presence of any of these heritable states. In addition, the relative risk for a stillbirth in the presence of one of these disorders is 3.6. These conditions are also associated with intrauterine growth retardation and preeclampsia. Proper management of heritable coagulopathies during pregnancy is essential to reduce the risk of these serious sequelae. Patients with newly diagnosed deep-vein thromboses or pulmonary emboli should be treated with therapeutic levels of unfractionated or low molecular weight heparin, followed by subsequent prophylactic heparin therapy. All patients with a history of thromboembolism before pregnancy or evidence of any of these coagulopathies may be offered prophylactic therapy with low molecular weight heparin. Patients with antithrombin III deficiency should receive full therapeutic heparin therapy for the entire pregnancy, irrespective of their thromboembolic history. Postpartum therapy with either heparin or warfarin is required in all cases.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the various heritable coagulopathies that can complicate pregnancy, to state the potential adverse effects of heritable coagulopathies in pregnancy, and to explain the management of heritable coagulopathies during pregnancy.

Measurement of the amniotic fluid index with and without color Doppler

AIMS

The purpose of this study was to assess the effect, if any, of color Doppler on the measurement of the amniotic fluid index in term pregnancies. It is hypothesized that color Doppler may enhance the detection of oligohydramnios.

METHODS

The amniotic fluid index was performed with and without color Doppler on pregnancies greater than or equal to 36 weeks gestational age. Differences in the mean amniotic fluid index measurements were assessed. The incidence of oligohydramnios was examined using both techniques. Differences in continuous variables were assessed with the paired t test, differences in categorical variables were assessed using the Fisher Exact Test.

RESULTS

There were 155 pregnancies examined, the amniotic fluid index was significantly decreased when color Doppler was added to the standard technique. (P < .0001) The incidence of oligohydramnios was higher with the application of color Doppler to the standard amniotic fluid index. (P < .05).

CONCLUSIONS

Color Doppler results in a significantly lower amniotic fluid volume measurement and may enhance the detection of oligohydramnios.

Implications of decidualization-associated protease expression in implantation and menstruation

During progesterone-induced decidualization of estradiol (E2)-primed human endometrial stromal cells (HESCs), the interstitial-type extracellular matrix (ECM) of the follicular phase endometrium is transformed in the luteal phase to a mixture of residual interstitial- and new basal laminar-type components. This transformation is accelerated by reduced proteolytic activity of HESCs undergoing decidualization (DZ). In cultured HESCs, progestins, but not E2, induce the expression of several DZ markers, and E2 enhances these effects despite the lack of response to E2 alone. Using this well-characterized in vitro DZ model we evaluated the expression of plasminogen activators (PAs), which degrade ECM components that undergo rapid turnover, and matrix metalloproteinases (MMPs), which degrade the bulk of ECM components. Medroxyprogesterone acetate (MPA) inhibited the catalytic activity of urokinase-type PA (uPA) and tissue-type PA (tPA) as well as the expression of such MMPs as interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3). Moreover, E2 + MPA elicited greater inhibitory effects on the expression of all of these proteases. Progestin inhibition of PA activities reflected reciprocal upregulation in the output of the PA inhibitor PAI-1, which produced large molar excesses of PAI-1 compared with the PAs in HESC-conditioned medium. By contrast, the tissue inhibitor of the MMPs, TIMP1, as well as gelatinase A (MMP-2), was constitutively expressed by the HESCs. In the absence of implantation, menstruation-associated degradation of the functional endometrial ECM is triggered by withdrawal of circulating ovarian steroids. This process was evaluated in cultured HESCs that were first decidualized during 10 days of exposure to E2 + MPA, and then withdrawn to steroid-free medium with and without the antiprogestin RU 486. As expected, steroid withdrawal reversed progestin-inhibited PA activity as well as the expression of MMP-1 and MMP-3 and progestin-enhanced PAI-1; much greater reversal was observed in medium supplemented with RU 486. Unlike the changes in PAI-1, neither TIMP1, nor MMP-2 expression was affected by withdrawal to steroid-free or to RU 486-medium. By altering the composition of the ECM of the luteal phase endometrium, progestin-elicited inhibition of the PAs, uPA and tPA, as well as that of the MMPs, MMP-1 and MMP-3, modulates trophoblast adhesion, migration and differentiation. Conversely, steroid withdrawal elicited increases in uPA, MMP-1 and MMP-3 activities would promote endometrial sloughing by degrading the mixture of decidual cell-derived basement membrane-like proteins and interstitial components that comprise the stromal ECM of the perimenstrual endometrium.

The decidua regulates hemostasis in human endometrium

Survival of the implanting human blastocyst requires that trophoblasts gain access to the maternal circulation. This is initially achieved when syncytiotrophoblasts breach endometrial capillarlies and venules. Subsequently, extravillous cytotrophoblasts penetrate the spiral arteries to induce their morphological transformation into high-flow, low-resistance vessels. This process provides the embryo with a requisite source of oxygen and nutrients, but risks decidual hemorrhage leading to abortion and abruption. Endovascular trophoblast invasion occurs within a matrix of decidualizing endometrial stromal cells. These decidual cells are temporally and spatially positioned to create a local hemostatic milieu which can counteract the threat of hemorrhage. Prior studies from our laboratory have established that decidual cells of luteal phase and pregnant endometrium express two crucial modulators of hemostasis: 1) tissue factor (TF), the primary initiator of hemostasis via factor Xa activation; and 2) plasminogen activator inhibitor type 1 (PAI-1), the fast inhibitor of the primary fibrinolytic agent, tissue type plasminogen activator. This coordinate increase in TF and PAI-1 expression provides a mechanism by which decidual cells control local hemostasis during endovascular trophoblast invasion. Cultures of human endometrial stromal cells and decidual cells isolated from first trimester endometrium demonstrate that progestins enhance TF and PAI-1 protein and mRNA expression via the induction of crucial intermediate transcription factors. Integration of these in vivo observations and in vitro studies suggest a model by which decidua acts to maintain hemostasis during implantation and placentation.

Neopterin concentrations in fetal and maternal blood: a marker of cell-mediated immune activation

OBJECTIVE

Neopterin is generated by macrophages and monocytes in response to cytokine and endotoxin stimulation and is a sensitive marker of the severity of infectious-, autoimmune-, and alloimmune-mediated inflammatory disorders. This study was designed to evaluate fetal and maternal neopterin concentrations during the second half of pregnancy.

STUDY DESIGN

We conducted a cross-sectional analysis of serum neopterin values with a sensitive radioimmunoassay in 35 paired fetal and maternal and 8 neonatal samples. The fetal and maternal samples were obtained between 20 and 38 weeks' gestation at the time of diagnostic cordocentesis. All maternal, fetal, and neonatal samples were derived from uncomplicated pregnancies resulting in term delivery of appropriately grown fetuses.

RESULTS

Fetal neopterin concentrations increased across gestation (r = 0.64, P <.001), and mean values were significantly higher than paired maternal values (6.28 [+/-2.44] ng/mL vs 2.05 [+/-0.87] ng/mL, P <.001]. In contrast, maternal neopterin concentrations did not correlate with gestational age (r = 0.22, P =.24). No significant correlation was found between fetal and maternal values (r = 0.34, P =.07).

CONCLUSION

Fetal neopterin values rise significantly across gestation. They are substantially greater than maternal levels and are not correlated significantly with paired maternal levels. These findings are the first report of a physiologically normal range for fetal neopterin concentrations in a sample of uncomplicated pregnancies. The values suggest progressive increases in fetal cell-mediated immunity and macrophage-monocyte activation as gestation progresses.