Placental cytokines and the pathogenesis of preeclampsia

Hypertension in response to chronic reductions in uterine perfusion in pregnant rats: effect of tumor necrosis factor-alpha blockade

Reductions in uterine perfusion pressure (RUPP) in pregnant rats is associated with increased tumor necrosis factor-alpha (TNF-alpha). This study was designed to determine the role of endogenous TNF-alpha in mediating changes in arterial pressure and endothelin-1 (ET-1) in RUPP rats. To achieve this goal we examined the effect of RUPP in the presence and absence of a TNF-alpha-soluble receptor, etanerecept (0.4 mg/kg). Mean arterial pressure increased from 102+/-1 mm Hg in normal pregnant (NP) rats to 134+/-3 mm Hg (P<0.05) in RUPP rats. Serum TNF-alpha increased to 40+/-7.6 pg/mL in RUPP rats (n=24) versus 14.8+/-3.3 pg/mL (n=16; P<0.05) in NP rats. Administration of etanerecept decreased TNF-alpha in RUPP rats (n=20) to 17.2+/-3 pg/mL and mean arterial pressure to 118+/-2 mm Hg (P<0.05). Tissue ET-1 decreased in etanerecept-treated RUPP rats compared with control RUPP rats. The direct effect of TNF-alpha blockade on endothelial activation in response to placental ischemia was examined in human umbilical vein endothelial cells. ET-1 secreted from human umbilical vein endothelial cells treated with RUPP serum was 59.2+16 pg/mg and decreased when etanerecept was added to the medium with RUPP serum (7.60+/-0.77 pg/mg), as well as in response to serum from etanerecept-treated RUPP rats (7.30+/-0.55 pg/mg; P<0.001). ET-1 secreted from human umbilical vein endothelial cells was 15.6+/-2 pg/mg when treated with NP serum. These data support the hypothesis that endogenous TNF-alpha is an important stimulus for ET-1 in response to placental ischemia and is important in mediating endothelial cell activation and hypertension during pregnancy.

Placental ischemia and cardiovascular dysfunction in preeclampsia and beyond: making the connections

Hypertensive disorders of pregnancy continue to be a significant source of maternal and fetal morbidity and mortality, and recent evidence suggests that the incidence of preeclampsia (PE) is increasing. Recent epidemiological studies indicate that the effects of PE may persist long after pregnancy, in both the mother and the offspring, as increased incidence of cardiovascular disease. The last decade has produced new insights into the pathogenesis of PE. The initiating event in PE appears to be impaired placental perfusion and subsequent placental ischemia, which results in the elaboration of numerous factors. Factors such as soluble fms-like tyrosine kinase-1, soluble endoglin and the angiotensin II type-1 receptor autoantibodies contribute to maternal endothelial and cardiovascular dysfunction, marked by increased reactive oxygen species and decreased bioavailable VEGF, nitric oxide and prostacyclin. However, the importance of the various endothelial and humoral factors that mediate these changes during PE remain to be elucidated.

Analytical approaches to detect maternal/fetal genotype incompatibilities that increase risk of pre-eclampsia

BACKGROUND

In utero interactions between incompatible maternal and fetal genotypes are a potential mechanism for the onset or progression of pregnancy related diseases such as pre-eclampsia (PE). However, the optimal analytical approach and study design for evaluating incompatible maternal/offspring genotype combinations is unclear.

METHODS

Using simulation, we estimated the type I error and power of incompatible maternal/offspring genotype models for two analytical approaches: logistic regression used with case-control mother/offspring pairs and the log-linear regression used with case-parent triads. We evaluated a real dataset consisting of maternal/offspring pairs with and without PE for incompatibility effects using the optimal analysis based on the results of the simulation study.

RESULTS

We identified a single coding scheme for the incompatibility effect that was equally or more powerful than all of the alternative analysis models evaluated, regardless of the true underlying model for the incompatibility effect. In addition, the log-linear regression was more powerful than the logistic regression when the heritability was low, and more robust to adjustment for maternal or fetal effects. For the PE data, this analysis revealed three genes, lymphotoxin alpha (LTA), von Willebrand factor (VWF), and alpha 2 chain of type IV collagen (COL4A2) with possible incompatibility effects.

CONCLUSION

The incompatibility model should be evaluated for complications of pregnancy, such as PE, where the genotypes of two individuals may contribute to the presence of disease.

A comparison of circulating TNF-alpha in obese and lean women with and without preeclampsia

OBJECTIVES

We hypothesized that TNF-alpha would be higher in obese versus lean women with preeclampsia.

METHODS

Total plasma TNF-alpha was measured in a nested case-control study of 123 nulliparous lean and obese control women and women with preeclampsia.

RESULTS

Adjusted mean TNF-alpha concentrations were 0.97 +/- 0.11 (pg/mL +/- SEM) in lean controls, 1.01 +/- 0.10 in obese controls, 1.43 +/- 0.11 in lean women with preeclampsia and 1.16 +/- 0.11 in obese women with preeclampsia. Pregnancy outcome was the single predictor of TNF-alpha concentration in the general linear regression model (p = 0.04).

CONCLUSION

TNF-alpha concentration was higher in preeclampsia compared with control subjects. Obesity was not associated with higher TNF-alpha concentrations in either preeclampsia or control subjects.

TNF-alpha alters nitric oxide- and endothelium-derived hyperpolarizing factor-mediated vasodilatation in human omental arteries

OBJECTIVE

To investigate the effect of TNF-alpha on the endothelial function of human systemic arteries.

METHODS

Omental arteries were obtained from healthy pregnant women undergoing Cesarean section and examined using isometric wire myography.

RESULTS

Incubation with TNF-alpha (1nM) alone did not alter bradykinin-mediated endothelium-dependent relaxation of arteries. However, TNF-alpha did attenuate nitric oxide- (NO) and prostacyclin-independent endothelial-mediated relaxation. Similarly, in vessels constricted with a high potassium solution (60 mM), which inhibits vasodilatation via endothelial-derived hyperpolarising factor (EDHF), TNF-alpha incubation also attenuated bradykinin-induced vasodilatation.

CONCLUSIONS

The vasorelaxant capacity of human systemic arteries is compromised by TNF-alpha incubation in the presence of NO/prostacyclin or EDHF-blockade.

Placental growth factor (PlGF) is a surrogate marker in preeclamptic hypertension

OBJECTIVE

To evaluate plasma levels of angiogenic factors and their association with preeclampsia.

METHODS

Twenty-three women with preeclampsia and nine normotensive pregnant women from the Maternity of Hospital das Clínicas of Belo Horizonte/MG-Brazil were assessed by National High Blood Pressure Education Program Working Group Creteria (NHBPEPWG). The plasma levels of vascular endothelial growth factor (VEGF) and Placental growth factor (PlGF) were determined by ELISA assay.

RESULTS

Plasma concentration of PlGF was 12-fold lower in preeclampsia versus non preeclampsia pregnancies. An inverse correlation was observed between PlGF plasma levels and mean arterial pressure (MAP); a decrease in 1pg/mL of PlGF resulted in 6.18 mm Hg increase in MAP.

CONCLUSION

These results indicate that PlGF is related to MAP in pregnant women.

The maternal plasma soluble vascular endothelial growth factor receptor-1 concentration is elevated in SGA and the magnitude of the increase relates to Doppler abnormalities in the maternal and fetal circulation

OBJECTIVES

The soluble form of vascular endothelial growth factor receptor-1 (sVEGFR-1), an antagonist to vascular endothelial growth factor and placental growth factor, has been implicated in the pathophysiology of preeclampsia. Preeclampsia and pregnancy complicated with small for gestational age (SGA) fetuses share some pathophysiologic derangements, such as failure of physiologic transformation of the spiral arteries, endothelial cell dysfunction, and leukocyte activation. The objectives of this study were to: (1) determine whether plasma concentrations of sVEGFR-1 in mothers with SGA fetuses without preeclampsia at the time of diagnosis are different from those in patients with preeclampsia or normal pregnant women, and (2) examine the relationship between plasma concentrations of sVEGFR-1 and Doppler velocimetry in uterine and umbilical arteries in patients with preeclampsia and those with SGA.

STUDY DESIGN

A cross-sectional study was conducted to determine the concentrations of the soluble form of VEGFR-1 in plasma obtained from normal pregnant women (n = 135), women with SGA fetuses (n = 53), and patients with preeclampsia (n = 112). Patients with SGA fetuses and those with preeclampsia were sub-classified according to the results of uterine and umbilical artery Doppler velocimetry examinations. Plasma concentrations of sVEGFR-1 were determined by an ELISA. Since these concentrations change with gestational age, differences among various subgroups were statistically estimated with the delta value, defined as the difference between the observed and expected plasma sVEGFR-1 concentration. The expected values were derived from regression analysis of plasma sVEGFR-1 concentrations in normal pregnancy. Regression analysis and univariate and multivariate analysis were employed.

RESULTS

(1) Mothers with SGA fetuses had a mean plasma concentration of sVEGFR-1 higher than normal pregnant women (p < 0.001), but lower than patients with preeclampsia (p < 0.001). (2) Among patients with SGA fetuses, only those with abnormal uterine artery Doppler velocimetry had a mean plasma sVEGFR-1 concentration significantly higher than normal pregnant women (p < 0.001). (3) Among mothers with SGA fetuses in whom Doppler velocimetry was performed (n = 41), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta of sVEGFR-1 plasma concentration (mean +/- standard deviation (SD): 0.69 +/- 0.29). Conversely, patients who had normal Doppler velocimetry in both uterine and umbilical arteries had the lowest mean delta (mean +/- SD: 0.09 +/- 0.29) of sVEGFR-1 plasma concentrations (ANOVA; p < 0.001). (4) Among patients with preeclampsia in whom Doppler velocimetry was performed (n = 69), those with abnormalities in both the uterine and umbilical artery velocimetry had the highest mean delta sVEGFR-1 plasma concentration (mean +/- SD: 1.01 +/- 0.22) among all groups classified (ANOVA; p < 0.001). (5) Among patients with SGA and those with preeclampsia, there was a relationship (Chi-square for trend p < 0.001 for both) between the severity of Doppler velocimetry abnormalities and the proportion of patients who had high delta sVEGFR-1 plasma concentrations (defined as a concentration two standard deviations (2SD) above the mean delta of normal pregnant women). (6) Multiple regression analysis suggested that the diagnostic category (e.g., SGA or preeclampsia), Doppler abnormalities, and gestational age at blood sampling were associated with an increase in plasma sVEGFR-1 concentrations (p < 0.001).

CONCLUSIONS

These observations provide support for the participation of the soluble receptor of vascular endothelial growth factor in the pathophysiology of SGA with abnormal uterine artery Doppler velocimetry and preeclampsia. An excess of sVEGFR-1 is released into the maternal circulation of patients with preeclampsia and those with SGA fetuses, as abnormalities of impedance to blood flow involve uterine and umbilical circulation.

Inducible nitric oxide synthase (iNOS) gene polymorphism in pre-eclampsia: a pilot study in North India

BACKGROUND

Pre-eclampsia is one of the most frequent complications of pregnancy, however, little is known about its aetiology.

AIMS

The objective of this study was to investigate the association between inducible nitric oxide synthase (iNOS) genotypes and pre-eclampsia. We also measured the concentrations of tumour necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and superoxide dismutase (SOD) in patients with pre-eclampsia to evaluate their relations to the single nucleotide polymorphisms (SNPs) observed.

METHODS

This cross-sectional study included 30 pregnant women with pre-eclampsia and 30 healthy pregnant women. They were screened at 28th, 36th weeks of gestation and just after delivery (within 48 h), and their blood samples were analysed for NO, SOD, TNF-alpha and iNOS gene polymorphism.

RESULTS

Patients with pre-eclampsia at 36 weeks gestation showed significantly increased serum NO levels (P=0.007), whereas SOD activity was decreased significantly (P=0.004). A doublefold increase was observed in TNF-alpha levels at 36 weeks in patients with pre-eclampsia (P=0.003) which decreased significantly (P=0.001) after delivery. A total of four SNPs were observed, of which two (G300A exon 8 and G274T exon 16) showed statistically significant association with pre-eclampsia. When compared, G274T exon 16 SNP also showed association with TNF-alpha levels and SOD activity in pre-eclamptic patients.

CONCLUSION

As pre-eclampsia is a disease of multifactorial aetiopathology, NO, TNF-alpha, SOD activity and NOS2A polymorphism might play an intermingled role in its development.

Autoantibody from women with preeclampsia induces soluble Fms-like tyrosine kinase-1 production via angiotensin type 1 receptor and calcineurin/nuclear factor of activated T-cells signaling

Preeclampsia is a pregnancy-specific hypertensive syndrome that causes substantial maternal and fetal morbidity and mortality. Recent evidence indicates that maternal endothelial dysfunction in preeclampsia results from increased soluble Fms-like tyrosine kinase-1 (sFlt-1), a circulating antiangiogenic protein. Factors responsible for excessive production of sFlt-1 in preeclampsia have not been identified. We tested the hypothesis that angiotensin II type 1 (AT(1)) receptor activating autoantibodies, which occur in women with preeclampsia, contribute to increased production of sFlt-1. IgG from women with preeclampsia stimulates the synthesis and secretion of sFlt-1 via AT(1) receptor activation in pregnant mice, human placental villous explants, and human trophoblast cells. Using FK506 or short-interfering RNA targeted to the calcineurin catalytic subunit mRNA, we determined that calcineurin/nuclear factor of activated T-cells signaling functions downstream of the AT(1) receptor to induce sFlt-1 synthesis and secretion by AT(1)-receptor activating autoantibodies. AT(1)-receptor activating autoantibody-induced sFlt-1 secretion resulted in inhibition of endothelial cell migration and capillary tube formation in vitro. Overall, our studies demonstrate that an autoantibody from women with preeclampsia induces sFlt-1 production via angiotensin receptor activation and downstream calcineurin/nuclear factor of activated T-cells signaling. These autoantibodies represent potentially important targets for diagnosis and therapeutic intervention.

Maternal periodontitis and adverse pregnancy outcomes

OBJECTIVES

Maternal periodontal diseases have been associated with increased risk of preterm birth and restricted fetal growth among relatively low socioeconomic groups. Whether the association can be generalized to middle-class populations remains uncertain. We evaluated periodontitis in relation to preterm birth (<37 weeks' gestation) and small-for-gestational-age (SGA, birth weight below the 10th percentile of birth weight for gestational age) among a group of medically insured women.

METHODS

We conducted a prospective study among participants of Project Viva, a US cohort study of pregnant women and their offspring from 1999 to 2002. Pregnancy outcomes were obtained from medical records. Self-reported periodontitis was assessed during the second trimester of pregnancy, and validated against radiographs. Logistic regression analyses were employed to evaluate the association of periodontitis with pregnancy outcomes adjusted for age, race/ethnicity, smoking status, income, frequency of dental check-ups, prepregnancy body mass index, pregnancy weight gain, gravidity, prior history of preterm birth and history of genitourinary infection.

RESULTS

Of the 1635 women, 72.7% were Caucasian, 65.0% had annual household income >$70 000, 3.8% reported having periodontitis, 6.4% delivered preterm, 5.4% delivered SGA babies, and 11.0% had poor pregnancy outcome (either preterm birth or SGA). The odds ratio (OR) associated with periodontitis was 1.74 (95% CI 0.65-4.66) for preterm delivery and 2.11 (95% CI 0.76-5.86) for SGA individually. When preterm delivery and/or SGA were combined, the OR was 2.26 (95% CI 1.05-4.85) relating periodontitis with poor pregnancy outcome.

CONCLUSION

Within the limitations of the study, the results suggest that periodontitis is an independent risk factor for poor pregnancy outcome among middle-class women.

Maternal serum soluble CD30 is increased in normal pregnancy, but decreased in preeclampsia and small for gestational age pregnancies

OBJECTIVE

Women with preeclampsia and those who deliver small for gestational age (SGA) neonates are characterized by intravascular inflammation (T helper 1 (Th1)-biased immune response). There is controversy about the T helper 2 (Th2) response in preeclampsia and SGA. CD30, a member of the tumor necrosis factor receptor superfamily, is preferentially expressed in vitro and in vivo by activated T cells producing Th2-type cytokines. Its soluble form (sCD30) has been proposed to be an index of Th2 immune response. The objective of this study was to determine whether the maternal serum concentration of sCD30 changes with normal pregnancy, as well as in mothers with preeclampsia and those who deliver SGA neonates.

METHODS

This cross-sectional study included patients in the following groups: (1) non-pregnant women (N = 49); (2) patients with a normal pregnancy (N = 89); (3) patients with preeclampsia (N = 100); and (4) patients who delivered an SGA neonate (N = 78). Maternal serum concentration of sCD30 was measured by a specific and sensitive enzyme-linked immunoassay. Non-parametric tests with post-hoc analysis were used for comparisons. A p value <0.05 was considered statistically significant.

RESULTS

(1) The median sCD30 serum concentration of pregnant women was significantly higher than that of non-pregnant women (median 29.7 U/mL, range 12.2-313.2 vs. median 23.2 U/mL, range 14.6-195.1, respectively; p = 0.01). (2) Patients with preeclampsia had a significantly lower median serum concentration of sCD30 than normal pregnant women (median 24.7 U/mL, range 7.6-71.2 vs. median 29.7 U/mL, range 12.2-313.2, respectively; p < 0.05). (3) Mothers with SGA neonates had a lower median concentration of sCD30 than normal pregnant women (median 23.4 U/mL, range 7.1-105.3 vs. median 29.7 U/mL, range 12.2-313.2, respectively; p < 0.05). (4) There was no significant correlation (r = -0.059, p = 0.5) between maternal serum sCD30 concentration and gestational age (19-38 weeks) in normal pregnant women.

CONCLUSIONS

(1) Patients with preeclampsia and those who deliver an SGA neonate had a significantly lower serum concentration of sCD30 than normal pregnant women. (2) This finding is consistent with the view that preeclampsia and SGA are associated with a polarized Th1 immune response and, perhaps, a reduced Th2 response.

Pathophysiology of hypertension during preeclampsia: linking placental ischemia with endothelial dysfunction

Studies over the last decade have provided exciting new insights into potential mechanisms underlying the pathogenesis of preeclampsia. The initiating event in preeclampsia is generally regarded to be placental ischemia/hypoxia, which in turn results in the elaboration of a variety of factors from the placenta that generates profound effects on the cardiovascular system. This host of molecules includes factors such as soluble fms-like tyrosine kinase-1, the angiotensin II type 1 receptor autoantibody, and cytokines such as tumor necrosis factor-alpha, which generate widespread dysfunction of the maternal vascular endothelium. This dysfunction manifests as enhanced formation of factors such as endothelin, reactive oxygen species, and augmented vascular sensitivity to angiotensin II. Alternatively, the preeclampsia syndrome may also be evidenced as decreased formation of vasodilators such as nitric oxide and prostacyclin. Taken together, these alterations cause hypertension by impairing renal pressure natriuresis and increasing total peripheral resistance. Moreover, the quantitative importance of the various endothelial and humoral factors that mediate vasoconstriction and elevation of arterial pressure during preeclampsia remains to be elucidated. Thus identifying the connection between placental ischemia/hypoxia and maternal cardiovascular abnormalities in hopes of revealing potential therapeutic regimens remains an important area of investigation and will be the focus of this review.

Role of sex steroids in modulating tumor necrosis factor alpha-induced changes in vascular function and blood pressure

BACKGROUND

We previously showed that the infusion of tumor necrosis factor alpha (TNF-alpha) induces hypertension and vascular dysfunction in late pregnant but not virgin rats. In the present study, we tested the hypothesis that levels of ovarian hormones to mimic pregnancy are required for TNF-alpha-induced changes in vascular function and blood pressure in rats.

METHODS

Twenty-one-day-release pellets containing 17beta-estradiol, progesterone, or both were implanted in ovariectomized (OVX) rats. Sham OVX rats were used as controls. Twelve days after implantation, TNF-alpha or vehicle was infused via osmotic minipumps (days 12 to 17). On day 18, mean arterial pressure was measured, and animals were sacrificed to assess vascular function.

RESULTS

Average estrogen and progesterone levels across all groups were 106 +/- 6 pg/mL and 88 +/- 5 ng/mL, respectively. The level of TNF-alpha was 41 +/- 7 pg/mL compared with OVX rats infused with vehicle (4 +/- 1 pg/mL). The results show that TNF-alpha did not cause elevated mean arterial pressure in OVX rats with increased estrogen, progesterone, or both. Vascular responses to the endothelium-dependent and independent agonists, acetylcholine and sodium nitroprusside, were also unchanged. Phenylephrine-induced contraction was moderately but significantly increased at the highest concentrations (10(-4) M) only in TNF-alpha-infused rats.

CONCLUSIONS

These data suggest that increased ovarian hormones to the levels observed during pregnancy are not sufficient to promote TNF-alpha-induced increases in blood pressure or vascular dysfunction.

Prediction of pre-eclampsia in early pregnancy

Pre-eclampsia is a multisystem disorder of pregnancy, usually characterized by the appearance of high blood pressure and the excretion of protein in the urine of a previously healthy woman. Symptoms and signs vary in intensity from woman to woman; from a borderline rise in blood pressure, to convulsions (eclampsia), stroke and death. The disease remits following removal of the placenta and so the mainstay of current treatment is timely delivery. A pathophysiological framework of the disease has been established, beginning with failures in placental development, inducing oxidative stress and release of compounds that lead to endothelial activation, vasoconstriction and glomerular endotheliosis. A combination of epidemiological, biophysical and biochemical tests now allow most patients at-risk to be identified by midpregnancy, whilst minimizing false-positive prediction. It is hoped that earlier classification of patients at-risk of the disease, on the basis of pathophysiological changes, will enable specific therapies to be developed targeting these changes.

Periodontal disease severity is related to high levels of C-reactive protein in pre-eclampsia

OBJECTIVE

Recent studies have shown that pre-eclamptic women present a high prevalence of periodontitis, suggesting that active periodontal disease may play a role in the pathogenesis of pre-eclampsia. The present study analysed the effect of periodontal disease in the concentrations of serum high-sensitivity C-reactive protein (hs-CRP), and its association with pre-eclampsia.

METHODS

A case-control study was carried out in Cali-Colombia, comprised of 398 pregnant women (145 cases and 253 controls) who were believed to have periodontal disease, between 28 and 36 weeks of gestational age. Pre-eclampsia cases were defined as blood pressure > or = 140/90 mmHg and proteinuria > or = 0.3 g/24 h. Controls were pregnant women with normal blood pressure, without proteinuria, matched by maternal age, gestational age and body mass index. Sociodemographic data, obstetric risk factors, periodontal state, subgingival microbial composition and hs-CRP levels were determined in both groups.

RESULTS

The case and control groups were comparable for sociodemographic characteristics. In women with pre-eclampsia and confirmed periodontal disease (n = 138), hs-CRP levels increased according to the severity of the disease (gingivitis median 4.14 mg/dl; mild periodontitis median 4.70 mg/dl; moderate/severe periodontitis median 8.8 mg/dl; P = 0.01). A similar tendency was observed in controls with periodontal disease (n = 251), but it did not reach statistical significance (gingivitis median 5.10 mg/dl; mild periodontitis median 5.12 mg/dl; moderate/severe periodontitis median 6.90 mg/dl; P = 0.07). A significant difference in hs-CRP levels was observed in pre-eclamptic women with moderate/severe periodontitis compared to controls (P = 0.01).

CONCLUSION

These findings suggest that chronic periodontitis may increase hs-CRP levels in pregnant women and lead to complications such as pre-eclampsia.

Hypoxic switch in mitochondrial myeloid cell leukemia factor-1/Mtd apoptotic rheostat contributes to human trophoblast cell death in preeclampsia

Preeclampsia, a disorder of pregnancy, is characterized by increased trophoblast cell death and altered trophoblast-mediated remodeling of myometrial spiral arteries resulting in reduced uteroplacental perfusion. Mitochondria-associated Bcl-2 family members are important regulators of programed cell death. The mechanism whereby hypoxia alters the mitochondrial apoptotic rheostat is essential to our understanding of placental disease. Herein, myeloid cell leukemia factor-1 (Mcl-1) isoform expression was examined in physiological/pathological models of placental hypoxia. Preeclamptic placentae were characterized by caspase-dependent cleavage of death-suppressing Mcl-1L and switch toward cell death-inducing Mcl-1S. In vitro, Mcl-1L cleavage was induced by hypoxia-reoxygenation in villous explants, whereas Mcl-1L overexpression under hypoxia-reoxygenation rescued trophoblast cells from undergoing apoptosis. Cleavage was mediated by caspase-3/-7 because pharmacological caspase inhibition prevented this process. Altitude-induced chronic hypoxia was characterized by expression of Mcl-1L; resulting in a reduction of apoptotic markers (cleaved caspase-3/-8 and p85 poly-ADP-ribose polymerase). Moreover, in both physiological (explants and high altitude) and pathological (preeclampsia) placental hypoxia, decreased trophoblast syncytin expression was observed. Hence, although both pathological and physiological placental hypoxia are associated with slowed trophoblast differentiation, trophoblast apoptosis is only up-regulated in preeclampsia, because of a hypoxia-reoxygenation-induced switch in generation of proapoptotic Mcl-1 isoforms.

Placental HIF-1 alpha, HIF-2 alpha, membrane and soluble VEGF receptor-1 proteins are not increased in normotensive pregnancies complicated by late-onset intrauterine growth restriction

Inadequate trophoblast invasion and spiral artery remodeling leading to poor placental perfusion are believed to underlie the pregnancy pathologies preeclampsia (PE) and intrauterine growth restriction (IUGR). The main objective of this study was to investigate hypoxia-inducible transcription factor-alpha (HIF-alpha) and downstream genes (VEGF receptor-1) Flt-1 and soluble fms-like tyrosine kinase 1 (sFlt-1) proteins in IUGR placentas. Placentas from normal pregnant (NP; n = 18), PE (n = 18), and IUGR (n = 10) patients were investigated. Normotensive patients with IUGR delivered babies at >or= 37 wk of gestation with birth weights of <10% and asymmetrical growth. HIF-1 alpha, -2 alpha, Flt-1, and sFlt-1 protein, and mRNA were assessed by Western and Northern blot analyses, respectively. The results are expressed as ratios of the densitometric values for each pair of pathologic and normal placentas, a ratio of 1.0 indicating no difference. Comparable to our earlier studies, the PE/NP ratios for HIF-1 alpha, -2 alpha, and Flt proteins were significantly increased by 50-100% (all P < 0.01 vs. 1.0). Unexpectedly, the IUGR/NP ratios for HIF-1 alpha and -2 alpha proteins were 1.03 +/- 0.07 and 0.96 +/- 0.16, respectively, and for Flt and sFlt were 1.14 +/- 0.15 and 0.95 +/- 0.12, respectively (all P = not significant vs. 1.0). Northern blot analysis revealed comparable levels of HIF-alpha mRNA in abnormal and normal placentas. In contrast to PE, HIF-alpha proteins and regulated genes are not increased in placentas from normotensive pregnant women delivering small, asymmetrically grown babies >or= 37 wk of gestation. The absence of an increase in HIF-alpha protein is not due to insufficient HIF-alpha mRNA for protein synthesis. Thus, the placentas from women with PE and late IUGR are fundamentally different at the molecular level.

Early growth response-1 mediates up-regulation of telomerase in placenta

Telomerase is thought to play a very important role in oncogenesis. It is also believed to wind back the "mitotic clock" which leads to ageing and enable permanent cell division. We evaluated telomerase activity in chorionic tissues, with particular attention to the early growth response-1 (EGR-1) gene, the importance of what was recently shown by Khachigian et al. We started our study by evaluating the relationship between activation of transcription of the human telomerase reverse transcriptase (hTERT) gene and EGR-1 gene. For this purpose, we first evaluated telomerase activity using the villous cancer cell lines JAR and JEG-3. We then demonstrated that EGR-1 plays an important role in activation of the transcription of hTERT by luciferase assay using hTERT promoter constructs. As a result of further computer analysis, we discovered a site postulated to be an EGR-1 consensus binding site at -273 to -281 in the hTERT promoter region. With forced expression of EGR-1, an increase in hTERT protein concentration was detected on Western blot analysis, while marked high expression of hTERT mRNA was observed by reverse transcriptase polymerase chain reaction. Furthermore, we evaluated the expression of EGR-1 and hTERT at the mRNA level in the placenta during the first, second and third trimesters of pregnancy and in patients with preeclampsia. Expression of EGR-1 and hTERT in the chorion increased in the first trimester of pregnancy and decreased later. Increased expression was noted in the placenta of patients with preeclampsia. The present findings suggest that EGR-1 plays an important role in activating the transcription of hTERT, showing that activation of the transcription of hTERT by EGR-1 is involved in the trophoblast growth mechanism.

Tumor necrosis factor-alpha in gestation and puerperium of women with gestational hypertension and pre-eclampsia

PROBLEM

High plasma levels of tumor necrosis factor-alpha (TNF-alpha) in pregnant women have been associated with the pathogenesis of pre-eclampsia (PE). This study evaluated TNF-alpha plasma levels and monocyte production in gestational hypertension (GH) and PE during gestation and at puerperium.

METHOD OF STUDY

This study included 128 women, of whom 20 were non-pregnant (NP) normotensive (NT), and 108 were pregnant: 36 NT, 27 with GH, and 45 with PE. Peripheral blood plasma was used for TNF-alpha and uric acid determination. TNF-alpha was determined in plasma and lipopolysaccharide (LPS)-stimulated and non-stimulated monocyte supernatants by L929 bioassay.

RESULTS

Tumor necrosis factor-alpha and uric acid plasma levels were higher in PE than in GH pregnancies. In both hypertensive groups, these parameters positively correlated and were significantly more elevated than in NT and NP women. TNF-alpha plasma levels and monocyte production were higher in hypertensive than in NT women during gestation, and significantly decreased at puerperium. Although decreased, TNF-alpha release in LPS-stimulated PE monocytes, was still significantly higher than in the other pregnant groups.

CONCLUSION

In vivo monocyte activation in GH and PE pregnant women was characterized by in vitro TNF-alpha production. The fact that higher circulating concentrations of TNF-alpha and uric acid were observed in PE than in GH suggests an association with disease severity.

Elevated Plasma Levels of Interleukin 1β, Tumour Necrosis Factor α and Monocyte Chemotactic Protein 1 Are Associated with Pregnancy Toxaemia in Ewes

Pregnancy toxaemia is a metabolic disorder that results from an inadequate energy supply to the growing maternal-fetal unit. The mechanism underlying the pathogenesis of the syndrome has not been fully clarified; however, a key role for cytokines and chemokines including interleukin 1 beta (IL-1 beta), tumour necrosis factor alpha (TNF-alpha) and monocyte chemotactic protein 1 (MCP-1) has been indicated in women and experimental animals. However, information on the maternal plasma levels of IL-1 beta, TNF-alpha and MCP-1 in ewes with pregnancy toxaemia is limited. Thus, the present study was designed to determine plasma IL-1 beta, TNF-alpha and MCP-1 concentrations in ewes with severe (n=6) and mild (n=4) naturally occurring pregnancy toxaemia and in uncomplicated pregnant ewes (n=10) using enzyme-linked immunosorbent assay (ELISA). All ewes with pregnancy toxaemia had significantly lower body temperature and respiratory rate than uncomplicated pregnant ewes (p<0.05). With the highest concentrations in severe cases, heart rate, proteinuria and serum uric acid levels as well as plasma IL-1 beta, TNF-alpha and MCP-1 were significantly different among all three groups (p<0.05). The plasma concentrations of IL-1 beta in control ewes and ewes with mild and severe toxaemia were 15.81 +/- 3.90 pg/ml, 23.83 +/- 2.42 pg/ml and 34.55 +/- 8.03 pg/ml, respectively. The plasma concentrations of TNF-alpha in control ewes and ewes with mild and severe toxaemia were 7.71 +/- 1.61 pg/ml, 16.13 +/- 3.63 pg/ml, and 22.85 +/- 3.64 pg/ml, respectively. The plasma concentrations of MCP-1 in control ewes and ewes with mild and severe toxaemia were 101.70 +/- 9.86 pg/ml, 134.75 +/- 6.24 pg/ml, and 157.67 +/- 9.69 pg/ml, respectively. Moreover, plasma IL-1 beta, TNF-alpha and MCP-1 levels were positively correlated with clinical and well-establish biochemical parameters of pregnancy toxaemia, serum uric acid and proteinuria (p<0.01). Concomitant increase of plasma IL-1 beta, TNF-alpha and MCP-1 concentrations along with serum uric acid, proteinuria, and worsening of the clinical signs indicates that such cytokines are involved in the aetiopathogenesis and in perpetuation of the local and systemic inflammatory reactions in pregnancy toxaemia in ewes. Hence, plasma IL-1 beta, TNF-alpha and MCP-1 may potentially serve as markers to monitor prognosis of pregnancy toxaemia in ewes.

Evaluation of maternal and umbilical serum TNFalpha levels in preeclamptic pregnancies in the intrauterine normal and growth-restricted fetus

OBJECTIVE

The aim of this study was to carry out a comparative analysis of the maternal and umbilical cord TNFalpha serum levels in pregnancies complicated by severe preeclampsia with normal intrauterine fetal growth, in preeclamptic pregnancies with intrauterine growth restriction (IUGR), and in normotensive pregnant patients.

PATIENTS AND METHODS

The study was carried out on eight patients with severe preeclampsia complicated by IUGR and 18 preeclamptic patients with normal intrauterine fetal growth. The control group consisted of 18 healthy normotensive patients with singleton uncomplicated pregnancies. Maternal and umbilical serum TNFalpha concentrations were estimated using a sandwich ELISA assay.

RESULTS AND CONCLUSIONS

Pregnant women with severe preeclampsia had significantly higher maternal and umbilical serum TNFalpha levels than those in the normotensive controls. Our findings and other reports indicate that TNFalpha may participate in the pathogenesis and sequelae of preeclampsia with and without IUGR. The results of excessive umbilical serum activity of tumor necrosis factor alpha (TNFalpha) in preeclamptic pregnancy complicated by intrauterine growth restriction (IUGR) may suggest additional changes and dysfunction of the placental-fetal unit and deterioration of placental function, leading to fetal hypotrophia in the course of preeclampsia.

Polymorphisms of interleukin-6, hepatic lipase and calpain-10 genes, and preeclampsia

OBJECTIVE

We determined whether single nucleotide polymorphisms (SNPs) in interleukin-6 (IL-6), hepatic lipase (HL) and calpain-10 (CAPN-10) genes contribute to susceptibility to develop preeclampsia.

STUDY DESIGN

The study involved 133 preeclamptic and 115 healthy pregnant women who were genotyped for the C-174G polymorphism in the IL-6 gene, the G-250A polymorphism in the HL gene and SNP 43 (G/A) in the CAPN-10 gene. The chi2-test was used to assess genotype and allele frequency differences between the preeclamptic and control groups.

RESULTS

No significant differences were detected in genotype and allele distributions of the C-174G polymorphism in the IL-6 gene, between the preeclampsia and control groups (p=0.98 and 0.85, respectively). With respect to the G-250A polymorphism in the HL gene, the genotype and allele distributions were similar in both groups (p=0.64 and 0.48, respectively). The genotype and allele distributions of SNP 43 in the CAPN-10 gene also showed no statistical differences in the preeclampsia and control groups (p=0.73 and 0.45, respectively).

CONCLUSIONS

The C-174G polymorphism in the IL-6 gene, the G-250A polymorphism in the HL gene and SNP 43 (G/A) in the CAPN-10 gene are unlikely to be major genetic factors predisposing Finnish women to preeclampsia.

Hypoxia and Reoxygenation: a Possible Mechanism for Placental Oxidative Stress in Preeclampsia

Preeclampsia is a human pregnancy-specific disorder that is diagnosed by the new appearance of hypertension and proteinuria after 20 weeks' gestation. It is a leading cause of perinatal morbidity and mortality, and the only intervention that effectively reverses the syndrome is delivery. Oxidative stress of the placenta is considered to be a key intermediary step in the pathogenesis of preeclampsia, but the cause for the stress remains unknown. Hypoxia-reoxygenation (H/R) injury, as a result of intermittent placental perfusion secondary to deficient trophoblast invasion of the endometrial arteries, is a possible mechanism. In this review, we present evidence to show that there is a plausible basis from which to assume that blood flow in the intervillous space will be intermittent in all normal pregnancies. The intermittency will be exacerbated by impaired conversion of the spiral arteries, or by the presence of atherotic changes that reduce their caliber as seen in preeclampsia. Placental oxidative stress can be the consequences of fluctuations in oxygen concentrations after H/R through the actions of reactive oxygen species. On this basis, there will be a complete spectrum of placental changes among the normal, the late onset and the early onset preeclamptic states. Viewing the syndrome as a continuum of H/R insults provides new insight into the pathophysiology of pregnancy that will hope fully lead to improved clinical interventions.

Hypertension produced by reductions in uterine perfusion in the pregnant rat: role of interleukin 6

The purpose of this study was to determine the role of interleukin (IL) 6 in mediating the increase in arterial pressure (AP) in response to chronic reductions in uterine perfusion pressure (RUPP) in pregnant rats. AP was higher in RUPP rats (138+/-1 mm Hg) than in normal pregnant (NP) rats (104+/-1 mm Hg). Serum IL-6 levels in the RUPP rats were 104.5+/-28.6 pg/mL as compared with 36.6+/-7.4 pg/mL in NP rats. To determine the long-term effects of a 2- to 3-fold elevation in plasma IL-6 on renal function and AP in pregnant rats, we infused IL-6 for 5 days (2.5 ng/day) in NP rats starting at day 14 of gestation. Five days later, serum IL-6 levels were 55.5+/-6.5 pg/mL in the control NP rats and 157.0+/-36.1 pg/mL in the IL-6-treated NP rats. AP was higher in the IL-6-treated NP rats (115+/-3 mm Hg) as compared with NP controls (101+/-1 mm Hg) at day 19 of gestation. Renal plasma flow and GFR were lower in the IL-6-treated NP rats than in the NP group. IL-6 increased plasma renin activity but did not affect endothelin in IL-6-treated NP rats. In contrast to the NP rats, IL-6 had no effect on AP or renal hemodynamics in virgin rats. In summary, these data indicate that plasma IL-6 is elevated in response to chronic reductions in uterine perfusion in pregnant rats and that a comparable elevation in plasma IL-6 increases AP and reduces renal function in pregnant rats.

First Trimester Markers for Pre-Eclampsia: Placental vs. Non-Placental Protein Serum Levels

BACKGROUND/AIM

Parallel investigation, in a matched case-control study, of the association of different first-trimester markers with the risk of subsequent pre-eclampsia (PE).

METHOD

The levels of different first trimester serum markers and fetal nuchal translucency thickness were compared between 52 cases of PE and 104 control women by non-parametric two-group comparisons and by calculating matched odds ratios.

RESULTS

In univariable analysis increased concentrations of inhibin A and activin A were associated with subsequent PE (p < 0.02). Multivariable conditional logistic regression models revealed an association between increased risk of PE and increased inhibin A and translucency thickness and respectively reduced pregnancy-associated plasma protein A (PAPP-A) and placental lactogen . However, these associations varied with the gestational age at sample collection. For blood samples taken in pregnancy weeks 12 and 13 only, increased levels of activin A, inhibin A and nuchal translucency thickness, and lower levels of placenta growth factor and PAPP-A were associated with an increased risk of PE.

CONCLUSIONS

Members of the inhibin family and to some extent PAPP-A and placental growth factor are superior to other serum markers, and the predictive value of these depends on the gestational age at blood sampling. The availability of a single, early pregnancy 'miracle' serum marker for PE risk assessment seems unlikely in the near future.

Immunological analogy between allograft rejection, recurrent abortion and pre-eclampsia - the same basic mechanism?

There are still controversies concerning the role of immunological mechanisms engaged both in recurrent abortions (RA) and pre-eclampsia (PE). According to some opinions, recurrent miscarriage is comparable to organ-specific autoimmune disease. Analysis of immune reactions shows that graft rejection shares many similar mechanisms with RA and PE. This fact allows us to conclude that rejection of transplanted alloantigenic organs and pregnancy loss have probably the same evolutionary origin. Subsets and functions of immunocompetent cells (T CD4, suppressor gammadeltaT, cytotoxic T CD8, Treg, Tr1, uterine NK cells), over-activation of innate immunity (activation of NK cytotoxic cells, macrophages, neutrophils and complement), changes of Th1/Th2 cytokine balance (IL-2, IL-12, IL-15, IL-18, IFNgamma, TNFalpha vs. IL-4, IL-10, TGFbeta), importance of HLA-G molecule, CD200/CD200R interaction, over-expression of adhesion molecules, fgl2 prothrombinase activation and stimulation of IDO and HO expression, all suggest that RA and PE are syndromes of fetal allograft rejection, and not organ-specific autoimmune diseases. According to that supposition, an analogy might exist between acute graft rejection and recurrent abortion, and between chronic graft rejection and pre-eclampsia.

Periodontitis is associated with preeclampsia in pregnant women

BACKGROUND

Recent investigations have demonstrated a positive association between periodontitis and pregnancy complications. The purpose of this study was to determine the effect of periodontitis and the subgingival microbial composition on preeclampsia.

METHODS

A case-control study was carried out in Cali, Colombia that included 130 preeclamptic and 243 non-preeclamptic women between 26 to 36 weeks of pregnancy. Sociodemographic data, obstetric risk factors, periodontal status, and subgingival microbial composition were determined in both groups. Preeclampsia was defined as blood pressure>or=140/90 mm Hg, and >or=2+ proteinuria, confirmed by 0.3 g proteinuria/24 hours of urine specimens. Controls were healthy pregnant women. Odds ratios (ORs) for periodontitis and subgingival microbiota compositions were calculated.

RESULTS

A total of 83 out of 130 preeclamptic women (63.8%) and 89 out of 243 controls (36.6%) had chronic periodontitis (OR: 3.0; 95% confidence interval (CI): 1.91 to 4.87; P<0.001). Clinical attachment loss increased in the case group (4.0+/-0.10 mm) compared to the control group (3.0+/-0.08 mm) (P<0.001). The average newborn birth weight from preeclamptic mothers was 2.453 g, whereas in controls was 2.981 g (P<0.001). Two red complex microorganisms, Porphyromonas gingivalis and Tannerella forsythensis, and the green complex microorganism Eikenella corrodens were more prevalent in the preeclamptic group than in controls (P<0.01).

CONCLUSIONS

Chronic periodontal disease and the presence of P. gingivalis, T. forsythensis, and E. corrodens were significantly associated with preeclampsia in pregnant women. Further research is needed to establish pathogenic mechanisms of active periodontal disease and subgingival periodontopathogens related to preeclampsia development.

Genomewide oligonucleotide microarray analysis on placentae of pre-eclamptic pregnancies

OBJECTIVE

Human placentae from normal and pre-eclamptic pregnancies were evaluated for possible changes in gene expression by microarray analysis to uncover new clues for the research of the etiology of pre-eclampsia.

METHODS

Placentae from five normal pregnancies and five pregnancies complicated by pre-eclampsia were collected. mRNA levels of five pre-eclamptic placentae were examined using genome-wide 70-mer oligonucleotide microarrays (CapitalBio, Beijing, China) in comparison with the pooled control consisting of total RNA from five normotensive placentae.

RESULTS

Ninety-six genes were found consistently down- or up-regulated in at least four pre-eclamptic samples. Most of them were related to an imbalance of reactive oxygen metabolites in placenta, abnormal trophoblast invasion, disorders of lipoprotein metabolism and signal transduction, or some that have been reported to have close correlation to the pathology of pre-eclampsia. The microarray data were also confirmed by the measurement of real-time PCR.

CONCLUSION

DNA microarray is a high throughput and time-saving method to monitor altered gene expression. The results could provide interesting clues to the etiology of pre-eclampsia and lead to further studies in a more targeted fashion.

Increased levels of macrophage migration inhibitory factor (MIF) in preeclampsia

OBJECTIVE

MIF is a proinflammatory cytokine involved in reproduction. Systemic activation of maternal inflammatory cell responses may play an important role in the pathogenesis of preeclampsia (PE). We hypothesized that MIF could be involved in preeclampsia.

STUDY DESIGN

Concentration of immunoreactive MIF was assayed by enzyme-linked immunoassorbent assay (ELISA) in maternal serum samples obtained from 41 term control pregnancies and 21 severe preeclamptic pregnancies (14 delivered before and 7 at or after 34 weeks).

RESULTS

MIF serum levels were significantly higher in preeclamptic pregnancies (median 12.74 ng/ml) than in control group (median 5.3n g/ml) p = 0.001. MIF concentration was significantly higher when delivery occurred <34 weeks (median 17.80 ng/ml; range 2.80-80.20) than in the group delivered > or = 34 weeks (median 6.16 ng/ml; range 1.62-23.65) p = 0.037.

CONCLUSIONS

High maternal serum levels MIF in pregnancies complicated by severe preeclampsia strongly support the role of inflammation in the pathogenesis of this disease.

Hypoxia promotes interleukin-6 and -8 but reduces interleukin-10 production by placental trophoblast cells from preeclamptic pregnancies

OBJECTIVE

Placental hypoxia and altered placental cytokine productions have been considered to play a significant role in the pathophysiology of preeclampsia. The objective of this study was to determine whether hypoxia could modify interleukin (IL)-6, IL-8, and IL-10 production by placental trophoblast cells (TCs) from normal and preeclamptic (PE) pregnancies.

METHODS

Placentas were obtained from nine normal and nine PE pregnancies immediately after delivery. Placental TCs were isolated and cultured under normoxic (21% O(2)/air) and hypoxic (2% O(2)/5% CO(2)/92% N(2)) conditions for 48 hours. TC productions of IL-6, IL-8, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA). Unpaired t tests or paired t test was used for the statistical analysis and data are expressed as means +/- SE (pg/mug cellular protein). A P value less than .05 was considered statistically significant.

RESULTS

PE-TCs produced significantly more IL-6, IL-8, and IL-10 than those of normal-TCs when they were cultured under normoxic condition, P < .05. Both normal-TCs and PE-TCs produced more IL-6 and IL-8 when they were cultured under hypoxic conditions. Hypoxia reduced IL-10 production by PE-TCs, but had no effect on IL-10 production by normal-TCs.

CONCLUSIONS

Hypoxia promotes both IL-6 and IL-8 but reduces IL-10 production by placental TCs from PE pregnancies.

Enhanced Endothelin Synthesis by Endothelial Cells Exposed to Sera From Pregnant Rats With Decreased Uterine Perfusion

The initiating event in preeclampsia is thought be to reduced uteroplacental perfusion. Although we have reported previously that chronic reductions in uterine perfusion pressure (RUPP) in pregnant rats results in hypertension and enhanced endothelin production, the factors linking placental ischemia and endothelial cell activation remain unclear. The purpose of this study was to determine the role of angiotensin II type-1 (AT1) receptor activation on endothelin production induced by serum from pregnant rats exposed to reductions in uterine perfusion. To achieve this goal, human umbilical vein endothelial cells were exposed to sera collected from RUPP rats or normal pregnant rats. Arterial pressure was significantly higher in RUPP rats (135+/-2 mm Hg) than in pregnant rats (106+/-1 mm Hg). Six hours after exposure to RUPP serum (n=17), cell media endothelin concentration was 18.4+/-2.7 pg/mL as compared with 9.22+/-1.3 pg/mL from cells exposed to serum from normal pregnant rats (n=9). Eighteen hours after exposure to RUPP serum (n=7), endothelin concentration was 30.5+/-3.8 pg/mL as compared with 12.8+/-5.3 pg/mL from cells exposed to normal pregnant rat serum (n=6). In contrast, serum from RUPP rats did not increase endothelin production in human umbilical vein endothelial cells pretreated with an AT1 receptor antagonist, losartan (15 micromol/L). Eighteen hours after exposure to RUPP serum and losartan (n=14), endothelin concentration was 21.3+/-2.2 pg/mL as compared with 16.4+/-3.3 pg/mL from cells exposed to normal pregnant rat serum and losartan (n=10). These data indicate that serum from pregnant rats exposed to reductions in uterine perfusion enhances endothelin production by endothelial cells via by AT1 receptor activation.

Hypoxia up-regulated angiogenin and down-regulated vascular cell adhesion molecule-1 expression and secretion in human placental trophoblasts

OBJECTIVE

Many processes that are involved in cellular invasion, including blastocyst implantation, placental development, and rapidly growing tumors, occur in reduced oxygen environments. It has been surmised that oxygen tension could regulate the cytotrophoblast ability to differentiate and, as a consequence, to express proteins that are critical for placentation. The objective of the current investigation was therefore to test the hypothesis that placental tissues and trophoblast cells in culture, under low oxygen tension, release angiogenic factors that could affect vascular behavior and invasive potential, thus providing a link between abnormal placentation and maternal vascular abnormality.

METHODS

Functionally active term placental explant culture and trophoblast cultures were used to demonstrate the secretion profiles of angiogenin and vascular cell adhesion molecule-1 (VCAM-1), and the real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) technique was employed to demonstrate the mRNA expression under both normoxic and hypoxic conditions.

RESULTS

A significant increase in the secretion (P <.01) and mRNA expression (P <.01) of angiogenin and a significant decrease in the secretion (P <.04) and mRNA expression (P <.03) of VCAM-1 from both term placental explants and trophoblast cultures subjected to hypoxia in vitro were observed.

CONCLUSION

Because the primary defect in uteroplacental insufficiency is placental maldevelopment probably associated with hypoxia in situ, this study provides molecular evidence to indicate that the differential expression and secretion of angiogenic factors may play an important role in these pathologic conditions.

Placental oxidative stress in a rat model of preeclampsia

The onset of preeclampsia is associated with increased maternal insult that could affect placental function. By increasing sodium intake (0.9% or 1.8% NaCl in drinking water) during the last week of gestation in the rat, we developed an animal model that shows many characteristics of preeclampsia such as increased blood pressure, decreased circulatory volume and diminished activity of the renin-angiotensin-aldosterone system. The aim of the present study was to determine in this model whether maternal perturbations in pregnancy lead to placental oxidative stress. Sprague-Dawley pregnant rats receiving salted-water were compared to not-supplemented pregnant rats. Markers of oxidative stress, ensuing cell death, and changes in the production of vasoactive substances (prostanoids: thromboxane, TxB(2); and prostacyclin, PGF(1alpha)) and the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) were measured in the placenta. In tissue from pregnant rats on 1.8% NaCl supplement, 8-iso-PGF(2alpha) levels, TxB(2)/6-keto-PGF(1alpha) ratios, total TNF-alpha RNA expression, as well as the apoptotic index (Bax/Bcl-2 ratio) and endothelial nitric oxide synthase protein expression increase while total glutathione content decreases. These findings demonstrate that maternal insult during gestation induced an imbalance in the oxidative environment in the placenta favouring oxidation. This was accompanied by an increased synthesis of vasoconstrictive substances and TNF-alpha by the placenta as well as the increased rate of placental cell apoptosis.

Monocytes of preeclamptic women spontaneously synthesize pro-inflammatory cytokines

The maternal syndrome preeclampsia is characterized by a generalized inflammatory response with activation of circulating leukocytes and altered levels of inflammatory cytokines. We hypothesized that one potential source of inflammatory cytokines during preeclampsia is the circulating maternal monocytes. By using flow cytometry, we found that the spontaneous intracellular synthesis of IL-1beta, IL-6, and IL-8 in monocytes of preeclamptic women was higher than in normal pregnant and non-pregnant women. The highest levels of cytokines were detected in women with the most abnormal laboratory values. When stimulated with lipopolysaccharide (LPS), the percentage of IL-1beta+ monocytes was lower in preeclampsia (72.6% +/- 8.2 SEM) than in normal pregnancy (90.7% +/- 2 SEM) (P = 0.03) and non-pregnant women (92.5% +/- 1.4 SEM) (P = 0.04) suggesting that monocytes from preeclamptic patients cannot be further stimulated. These results indicate that maternal circulating monocytes represent a source of inflammatory cytokines during preeclampsia.

Evidence supporting that the excess of the sVEGFR-1 concentration in maternal plasma in preeclampsia has a uterine origin

BACKGROUND

Preeclampsia has been considered an anti-angiogenic state. Two factors have been implicated in the genesis of this state: soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and placental growth factor (PlGF). Indeed, the concentrations of PlGF, an angiogenic factor, are lower in preeclampsia than in normal pregnancy, while the opposite is the case for the anti-angiogenic factor, sVEGFR-1. The source of the excess sVEGFR-1 has not yet been determined. Since the placenta could be a source of sVEGFR-1, we conducted a study to determine whether there is a gradient in the plasma concentration of sVEGFR-1 and PlGF between the uterine vein and the antecubital vein in both patients with preeclampsia and normal pregnant women.

METHODS

A cross-sectional study was performed to determine the plasma concentrations of sVEGFR-1 and PlGF in the uterine and antecubital vein of patients with preeclampsia (n = 9) and normal pregnant women at term (n = 9). Plasma samples were collected from antecubital and uterine veins at the time of cesarean section. The concentrations of sVEGFR-1 and PlGF were determined using specific enzyme-linked immunoassays. The differences of plasma concentrations of sVEGFR-1 and PlGF between uterine and antecubital veins in both groups were compared by paired t-tests.

RESULTS

Patients with preeclampsia had a significantly higher mean plasma concentration of sVEGFR-1 in the uterine vein than in the antecubital vein (uterine vein: mean 13,675 +/- 5,684 pg/ml vs. antecubital vein: mean 10,234 +/- 4,700 pg/ml; paired t-tests, p = 0.04). In contrast, among normal pregnant women at term, there was no significant difference in plasma concentrations of sVEGFR-1 between the uterine and antecubital veins (uterine vein: mean 1,918 +/- 665 pg/ml vs. antecubital vein: mean 1,750 +/- 475 pg/ml; paired t-tests, p = 0.1). The mean plasma concentration of sVEGFR-1, either in the antecubital or uterine vein, was significantly higher in preeclampsia than in normal pregnancy (unpaired t-tests; both p < 0.001). There was no significant difference in the mean plasma concentration of PlGF between the uterine and the antecubital veins in both the preeclamptic (uterine vein, mean +/- SD: 129 +/- 106 pg/ml vs. antecubital vein, mean +/- SD: 82 +/- 43 pg/ml; paired t-tests, p = 0.2) and normal pregnancy groups (uterine vein, mean +/- SD: 331 +/- 254 pg/ml vs. antecubital vein, mean +/- SD: 319 +/- 259 pg/ml; paired t-tests, p = 0.4). The mean plasma concentration of PlGF, either in the uterine or antecubital vein, was lower in preeclampsia than in normal pregnancy (unpaired t-tests; p = 0.008 and 0.02 respectively).

CONCLUSIONS

Plasma concentration of sVEGFR-1 was higher in the uterine vein than in the antecubital vein in women with preeclampsia. This provides evidence supporting the concept that the uterus is a potential source of the excess circulating sVEGFR-1 concentration in preeclamptic women.

Cytokine mapping of sera from women with preeclampsia and normal pregnancies

INTRODUCTION

Preeclampsia is a pregnancy-specific syndrome. The immune system in preeclampsia is changed with an increased innate activity and there is a hypothesis of a shift towards Th1-type immunity. The aim of this study was to determine a spectrum of soluble immunological factors denoting different aspects of immune activation in third trimester sera from women with preeclampsia (N=15) and compare with levels in sera from normal pregnant women (N=15).

MATERIAL AND METHODS

IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 p40, IL-13, IL-15, IL-17, IFN-alpha, IFN-gamma, TNF-alpha, GM-CSF, MIP-lalpha, MIP-1beta, MCP-1, eotaxin and RANTES were measured in serum using multiplex bead arrays. The levels of soluble CD14 and soluble IL-4 receptor were measured by enzyme-linked immunoassay (ELISA).

RESULTS

Preeclamptic women had significantly increased levels of circulating IL-6 (p=0.002), IL-8 (p=0.003) and soluble IL-4R (p=0.037), compared to women with normal pregnancies.

CONCLUSION

This study supports the hypothesis of increased inflammatory responses in preeclampsia, illustrated by the increased levels of IL-6 and IL-8. The finding of increased levels of soluble IL-4 receptor is an intriguing finding with several interpretations, which may partly support the hypothesis of a Th1 shift in preeclampsia.

The role of cytokines in mediating effects of prenatal infection on the fetus: implications for schizophrenia

Maternal infections with bacterial or viral agents during pregnancy are associated with an increased incidence of schizophrenia in the offspring at adulthood although little is known about the mechanism by which maternal infection might affect fetal neurodevelopment. Exposure of pregnant rodents to the bacterial endotoxin, lipopolysaccharide (LPS), results in behavioral deficits in the adult offspring that are relevant to schizophrenia. It is however unknown whether these effects are due to the direct action of the inflammatory stimulus on the developing fetus, or due to secondary immune mediators (cytokines) activated at maternal/fetal sites. In this study we sought to elucidate the site of action of LPS, following a single intraperitoneal (i.p.) injection, in pregnant rats at gestation day 18. Animals received 5 muCi of iodinated LPS ((125)I-LPS) and its distribution was assessed in maternal/fetal tissues (1-8 h). In addition, induction of the inflammatory cytokines, TNF-alpha, IL-1beta and IL-6, was measured in maternal/fetal tissues following maternal LPS challenge (0.05 mg/kg, i.p.) (2-8 h). (125)I-LPS was detected in maternal tissues and placenta, but not the fetus. This distribution was accompanied by significant increases in TNF-alpha, IL-1beta and IL-6 in maternal plasma and placenta, but not in fetal liver or brain. A significant increase in IL-1beta was however detected in fetal plasma, possibly due to transfer from the maternal circulation or placenta. Collectively, these data suggest that effects of maternal LPS exposure on the developing fetal brain are not mediated by the direct action of LPS, but via indirect actions at the level of the maternal circulation or placenta.

Urinary calcium excretion in severe preeclampsia and eclampsia

Urinary calcium levels in women with mild preeclampsia, severe preeclampsia and eclampsia were evaluated in this study. We collected 24-h urine samples from 35 mild preeclamptic (Group 1), 30 severe preeclamptic (Group 2), and 17 eclamptic patients (Group 3). The control group (Group 4) consisted of 35 healthy pregnant women. Serum levels of total calcium and creatinine, and urinary calcium were measured. These values were compared in the four groups. The mean maternal age and parity were similar in all groups. There were no statistically significant differences in the serum levels of total calcium and creatinine (p>0.05). Urinary calcium excretion in patients with preeclampsia and eclampsia was significantly lower than in controls (p<0.0001). Urinary calcium levels between mild preeclampsia and severe pre-eclampsia, and severe preeclampsia and eclampsia were similar (p>0.05), but were lower in eclampsia than in mild preeclampsia (p<0.05). In conclusion, urinary calcium excretion is reduced in patients with severe preeclampsia or eclampsia. However, the decrease in urinary calcium excretion cannot be used to identify the severity of preeclampsia, or to predict impending eclampsia.

Different effects of magnesium sulfate and angiotensin II on the capacity of the fetal and maternal compartments of normal human placenta to secrete TNF-alpha and IL-6

Three different protocols were carried out to evaluate the effect of magnesium sulfate (MgSO4) on the capacity of the normal human placenta to secrete TNF-alpha and IL-6 in presence and absence of angiotensin II (AII). Ten placentas were perfused with MgSO4 (6-7 mg%) or medium in the absence or presence of AII. Perfusate samples from fetal and maternal sites were collected and examined for IL-6 and TNF-alpha by ELISA. The maternal site of placentas exposed to AII showed only basal levels of TNF-alpha. Exposure of the placentas to MgSO4 resulted in significant increase in TNF-alpha and IL-6 in the maternal site (p < 0.05). However, the effect of MgSO4 was significantly attenuated by AII injected in presence of MgSO4. TNF-alpha and IL-6 levels in the maternal site significantly decreased (p < 0.05). The fetal site of the placentas exposed to MgSO4 or AII separately showed only basal levels of TNF-alpha and IL-6. However, TNF-alpha and IL-6 levels were significantly higher after injection of AII in the presence of MgSO4 compared to TNF-alpha levels in the fetal site of placentas exposed to AII alone (p < 0.05) or MgSO4 alone (p < 0.01). MgSO4 induced the ability of the placental maternal site to secrete TNF-alpha and IL-6. In the presence of both MgSO4 and AII, the effect of MgSO4 on the maternal site was significantly reduced. However, in the fetal site, MgSO4 alone had no significant effect on TNF-alpha and IL-6 levels although, in presence of AII and MgSO4, there was a significant increase in TNF-alpha and IL-6 levels. Elevation of TNF-alpha and IL-6 in the fetal compartment, which may affect fetal brain growth and development and placental function should be considered before administration of MgSO4 during pregnancy.