Endothelial cell expression of adhesion molecules is induced by fetal plasma from pregnancies with umbilical placental vascular disease

Heme Oxygenase Protects against Placental Vascular Inflammation and Abortion by the Alarmin Heme in Mice

Both infectious as non-infectious inflammation can cause placental dysfunction and pregnancy complications. During the first trimester of human gestation, when palatogenesis takes place, intrauterine hematoma and hemorrhage are common phenomena, causing the release of large amounts of heme, a well-known alarmin. We postulated that exposure of pregnant mice to heme during palatogenesis would initiate oxidative and inflammatory stress, leading to pathological pregnancy, increasing the incidence of palatal clefting and abortion. Both heme oxygenase isoforms (HO-1 and HO-2) break down heme, thereby generating anti-oxidative and -inflammatory products. HO may thus counteract these heme-induced injurious stresses. To test this hypothesis, we administered heme to pregnant CD1 outbred mice at Day E12 by intraperitoneal injection in increasing doses: 30, 75 or 150 μmol/kg body weight (30H, 75H or 150H) in the presence or absence of HO-activity inhibitor SnMP from Day E11. Exposure to heme resulted in a dose-dependent increase in abortion. At 75H half of the fetuses where resorbed, while at 150H all fetuses were aborted. HO-activity protected against heme-induced abortion since inhibition of HO-activity aggravated heme-induced detrimental effects. The fetuses surviving heme administration demonstrated normal palatal fusion. Immunostainings at Day E16 demonstrated higher numbers of ICAM-1 positive blood vessels, macrophages and HO-1 positive cells in placenta after administration of 75H or SnMP + 30H. Summarizing, heme acts as an endogenous “alarmin” during pregnancy in a dose-dependent fashion, while HO-activity protects against heme-induced placental vascular inflammation and abortion.

Maternal Plasma From Pregnant Women With Umbilical Placental Vascular Disease Does Not Affect Endothelial Cell mRNA Expression of Nitric Oxide Synthase

OBJECTIVE

In placental vascular disease identified by umbilical artery Doppler study we have shown the existence of a factor in fetal plasma that causes activation of endothelial cells in culture with expression of cell adhesion molecules and nitric oxide synthase, apoptosis, and proinflammatory cytokine production. The present work was carried out to investigate a maternal origin for this factor active in the fetal circulation.

METHODS

We collected maternal plasma from pregnant women with Doppler-defined umbilical placental vascular disease and examined its effect on endothelial cells in culture. Aliquots from a common culture of human umbilical vein endothelial cells (HUVEC) were incubated with maternal plasma from women with normal pregnancy (n = 23), umbilical placental vascular disease defined by abnormal umbilical artery Doppler (n = 30, with or without preeclampsia), and preeclampsia with normal umbilical artery Doppler (n = 14). The expression of mRNA for inducible and endothelial constitutive nitric oxide synthase (iNOS and ecNOS, respectively) was assessed by reverse transcriptase polymerase chain reaction.

RESULTS

There was no significant increase in either the iNOS or the ecNOS mRNA expression by HUVEC cultured with maternal plasma from pregnancies with umbilical placental vascular disease compared with normal pregnancy (iNOS 1.49 +/- 0.35 versus 1.38 +/- 0.25; ecNOS 1.51 +/- 0.35 versus 1.25 +/- 0.27; P >.05). In the placental vascular disease group the results were similar for the presence or absence of maternal preeclampsia. In the samples from women with preeclampsia with normal umbilical Doppler, both iNOS and ecNOS mRNA expression (iNOS 1.42 +/- 0.53; ecNOS 1.46 +/- 0.39; P >.05) did not differ from normal.

CONCLUSION

Maternal plasma from pregnancies with umbilical placental vascular disease did not affect endothelial cell expression of nitric oxide synthase. This finding does not support a maternal origin for the factor demonstrated in fetal plasma. These results suggest separate pathogenic pathways for the endothelial cell activation seen in preeclampsia and fetal growth restriction associated with abnormal umbilical artery Doppler flow velocity waveforms. These findings are also consistent with the concept that the vascular pathology in the fetal placenta may be primary and that the uteroplacental circulation is reduced in response rather than acts as a constraint.

Fetuses Delivered Following Preterm Prelabor Rupture of the Membranes are Capable of Stimulating a Proinflammatory Response in Endothelial Cells

OBJECTIVE

Preterm premature rupture of the membranes (PROM) has been attributed to ascending infection and a choriodecidual inflammatory response (ie, on the maternal side). However, on the fetal side those most at risk of morbidity have a systemic proinflammatory cytokine response. We have recently defined a similar proinflammatory response in pregnancies complicated by vascular disease on the fetal side of the placenta. A factor(s) present in fetal plasma from these pregnancies can stimulate human umbilical vein endothelial cells (HUVECs) to express mRNA for the proinflammatory cytokines, interleukin (IL)-6 and IL-8. The hypothesis of this study was that a similar factor(s) was present in preterm PROM.

METHODS

A standard culture of HUVECs was incubated with fetal plasma, obtained immediately following delivery, from normal pregnancies delivering vaginally at term (n=16) and pregnancies delivering following preterm PROM (n=19). Expression of mRNA for IL-6 and IL-8 was assessed by reverse transcription polymerase chain reaction (RT-PCR) and standardized to GAPDH mRNA expression.

RESULTS

Endothelial cell expression of IL-6 mRNA (median [25-75th centile] 0.295 [0.252-0.507] vs term vaginal delivery 0.208 [0.151-0.307]; P=.009) was enhanced in response to the fetal plasma from PROM cases compared to pregnancies delivering vaginally at term. In contrast, mRNA expression of IL-8 (median [25-75th centile] preterm PROM 0.41 [0.21-0.78] vs term vaginal delivery 0.49 [0.16-0.68]; P=.46) was not different in the two groups.

CONCLUSIONS

We have demonstrated that in fetuses delivered following preterm PROM there is a factor(s) capable of stimulating a local endothelial cell proinflammatory cytokine (IL-6) response. This factor(s) that we have demonstrated may be responsible for the increased cytokine production seen in fetuses with the fetal inflammatory response syndrome.

Post-transcriptional down regulation of ICAM-1 in feto-placental endothelium in GDM

Maternal gestational diabetes (GDM) is associated with hyperglycaemia and hyperinsulinemia in the fetal circulation which consequently may induce endothelial dysfunction in the feto-placental vasculature. In fact, feto-placental vasculature reveals various morphological changes in response to GDM. The cell adhesion molecules (CAMs) ICAM-1, VCAM-1 and E-selectin promote attachment and trans-endothelial migration of leukocytes, and are up regulated in inflammation and endothelial dysfunction. Thus, we hypothesized that the GDM environment upregulates ICAM-1, VCAM-1 and E-selectin in the feto-placental endothelium. We isolated primary feto-placental endothelial cells (fpEC) after normal (n=18) and GDM pregnancy (n=11) and analyzed mRNA (RT-qPCR) and protein expression (Immunoblot) of ICAM-1, VCAM-1 and E-selectin. While other CAMs were unchanged on mRNA and protein levels, ICAM-1 protein was decreased by GDM. Further analysis revealed also a decrease in the release of soluble ICAM-1 (sICAM-1), whose levels correlated negatively with maternal BMI. We conclude that this reduction of ICAM-1 protein species is the result of post-translational regulation, since ICAM-1 mRNA expression was unchanged. In fact, miRNAs targeting ICAM-1 were upregulated in GDM fpEC. Immunohistochemistry showed weaker ICAM-1 staining in the placental endothelium after GDM pregnancies, and demonstrated ICAM-1 binding partners CD11a and CD18 expressed on leukocytes in fetal circulation and on placental tissue macrophages. This study identified reduction of ICAM-1 protein in fpEC in GDM pregnancy, which was regulated post-transcriptionally. Low ICAM-1 protein production may represent a protective, placenta-specific mechanism to avoid leukocyte transmigration into the placenta in response to GDM.

The loss of sustained Ca(2+) signaling underlies suppressed endothelial nitric oxide production in preeclamptic pregnancies: implications for new therapy

Approximately 8% of pregnancies are complicated by preeclampsia (PE), a hypertensive condition characterized by widespread endothelial dysfunction. Reduced nitric oxide (NO) output in PE subjects has been inferred but not directly measured, and there is little understanding of why this occurs. To address this we have used direct imaging of changes in intracellular Ca(2+) concentration ([Ca(2+)]i) and NO in umbilical vein endothelium of normal and PE subjects that is still intact and on the vessel luminal surface. This was achieved by dissection and preloading with fura 2 and DAF-2 imaging dyes, respectively, before subsequent challenge with ATP (100 μM, 30 min). As a control to reveal the content of active endothelial nitric oxide synthase (eNOS) per vessel segment, results were compared with a maximal stimulus with ionomycin (5 μM, 30 min). We show for the first time that normal umbilical vein endothelial cells respond to ATP with sustained bursting that parallels sustained NO output. Furthermore, in subjects with PE, a failure of sustained [Ca(2+)]i bursting occurs in response to ATP and is associated with blunted NO output. In contrast, NO responses to maximal [Ca(2+)]i elevation using ionomycin and the levels of eNOS protein are more similar between groups than the responses to ATP. When the endothelial cells from PE subjects are isolated and allowed to recover in culture, they regain the ability under fura 2 imaging to show multiple [Ca(2+)]i bursts otherwise seen in the cells from normal subjects. Thus novel clinical therapy aimed at restoring function in vivo may be possible.

eNOS activation and NO function: pregnancy adaptive programming of capacitative entry responses alters nitric oxide (NO) output in vascular endothelium--new insights into eNOS regulation through adaptive cell signaling

In pregnancy, vascular nitric oxide (NO) production is increased in the systemic and more so in the uterine vasculature, thereby supporting maximal perfusion of the uterus. This high level of functionality is matched in the umbilical vein, and in corresponding disease states such as pre-eclampsia, reduced vascular responses are seen in both uterine artery and umbilical vein. In any endothelial cell, NO actually produced by endothelial NO synthase (eNOS) is determined by the maximum capacity of the cell (eNOS expression levels), eNOS phosphorylation state, and the intracellular [Ca(2+)](i) concentration in response to circulating hormones or physical forces. Herein, we discuss how pregnancy-specific reprogramming of NO output is determined as much by pregnancy adaptation of [Ca(2+)](i) signaling responses as it is by eNOS expression and phosphorylation. By examining the changes in [Ca(2+)](i) signaling responses from human hand vein endothelial cells, uterine artery endothelial cells, and human umbilical vein endothelial cells in (where appropriate) nonpregnant, normal pregnant, and pathological pregnant (pre-eclamptic) state, it is clear that pregnancy adaptation of NO output occurs at the level of sustained phase 'capacitative entry' [Ca(2+)](i) response, and the adapted response is lacking in pre-eclamptic pregnancies. Moreover, gap junction function is an essential permissive regulator of the capacitative response and impairment of NO output results from any inhibitor of gap junction function, or capacitative entry using TRPC channels. Identifying these [Ca(2+)](i) signaling mechanisms underlying normal pregnancy adaptation of NO output not only provides novel targets for future treatment of diseases of pregnancy but may also apply to other common forms of hypertension.

Placental apoptosis and adhesion molecules expression in the placenta and the maternal placental bed of pregnancies complicated by fetal growth restriction with and without pre-eclampsia

The aim of the study was to examine the expression of adhesion molecules VCAM-1 and ICAM-3 in placental tissue samples and placental bed (maternal decidual tissue) biopsies of pregnancies complicated by pre-eclampsia (PE) and fetal growth restriction (FGR), and to determine whether PE and FGR are associated with an increase in placental apoptosis. We studied placentas and placental bed samples of 49 third trimester pregnancies complicated by FGR (26 with associated PE, 23 without PE) and 25 normotensive healthy pregnant women. Placental apoptosis was assessed by the TUNEL method. Immunohistochemistry was used to assess expression of the VCAM-1 and ICAM-3. There was no significant difference in the staining intensity of VCAM-1 in placentas (p=0.472) and placental bed biopsies (p=0.754) of women delivering appropriate for gestational age and growth restricted fetuses (with and without associated PE). The amount of lymphocytes staining positively with ICAM-3 was significantly higher in both placental and placental bed biopsies of women delivering growth restricted fetuses compared with control pregnancies (p<0.001). Fetal growth restricted pregnancies with associated PE showed higher staining of ICAM-3 in placental compared with placental bed samples (p=0.049). In fetal growth restricted placentas, apoptotic nuclei were more abundant compared with control placentas (p<0.001). Increased expression of ICAM-3 on lymphocyte surface of both maternal and fetal side, suggests lymphocyte overactivation in PE and FGR. Increased placental apoptosis may play an important role in the pathogenesis or sequelae of PE.

Placenta and fetal growth restriction

The placenta, as the vector for all maternal-fetal oxygen and nutrient exchange, is a principal influence on birthweight. Placental weight summarizes laterally expanding growth of the chorionic disc, and villous arborization yielding the nutrient exchange surface. These different growth dimensions alter fetoplacental weight ratio and ponderal index, and thus may modify placental functional efficiency. The placenta may show a range of histopathologies, some of which are also associated with fetal growth restriction. Different fetal intrinsic abilities to compensate for gross and histo-pathology may clarify the imperfect relationships between fetal growth and both intrauterine pathology, and the long-term health risks associated with poor fetal growth.

Short-term sPECAM-Fc treatment ameliorates EAE while chronic use hastens onset of symptoms

The homophilic cell adhesion molecule PECAM-1 is a major participant in the migration of leukocytes across endothelium. We examined the ability of a chimeric soluble PECAM-1 fused to human IgG-Fc to impair leukocyte entry through the blood-brain barrier and reduce CNS autoimmunity. sPECAM-Fc impaired migration of lymphocytes across brain endothelial monolayers and diminished the severity of EAE, an experimental model of MS, when administered at the onset of symptoms. However, in mice transgenic for sPECAM-Fc, the chronically elevated levels of sPECAM-Fc hastened onset of EAE disease without significantly changing clinical score severity. Our data suggest that short-term treatment of diseases like MS with sPECAM-Fc has therapeutic potential.

Egr-1 transcription activation exists in placental endothelium when vascular disease is present

OBJECTIVE

To seek evidence of early vascular injury in the placental villous microcirculation in placental insufficiency identified by a high-resistance umbilical Doppler study by examining for expression of fibroblast growth factor receptor-1 (FGFR-1), its transcription factor, early growth response factor-1 (Egr-1) and plasma fibroblast growth factor-2 (FGF-2).

DESIGN

Case-control study.

SETTING

University teaching hospital.

SAMPLE

Placentas and umbilical vein blood were collected at delivery from 12 women with normal pregnancy delivered at term and 14 with placental vascular disease defined by an abnormal umbilical artery Doppler study.

METHODS

Microvascular endothelial cells were isolated from fresh human placentas using collagenase digestion and Dynabeads coated with monoclonal antibody against CD31. RNA was extracted from the isolated endothelial cells. The messenger RNA (mRNA) expression of FGFR-1 and Egr-1 production were assessed by reverse transcription polymerase chain reaction and factored relative to 18S ribosomal RNA. To confirm that FGF-2 was playing a significant role in this microvascular endothelial cell injury in the placenta, we also measured the soluble fraction of FGF-2 in fetal plasma from same groups of pregnancies using an enzyme-linked immunosorbent assay.

MAIN OUTCOME MEASURES

Microvascular endothelial cells expression of Egr-1mRNA, FGFR-1 mRNA and presence of soluble FGF-2 in fetal plasma.

RESULTS

The soluble level of FGF-2 in the fetal placental circulation from pregnancy with placental vascular disease was increased when compared with normal pregnancy (median 10.15 pg/ml and interquartile range 5.34-21.83 pg/ml versus 4.46 pg/ml and 3.69-5.66 pg/ml; P < 0.05). Microvascular endothelial cells from the placental villi with placental vascular disease showed upregulation of both FGFR-1 mRNA expression (median 0.72 and interquartile range 0.40-1.64 versus 0.34 and 0.19-0.71; P<0.05) and Egr-1 expression (median 0.79 and interquartile range 0.27-1.86 versus 0.23 and 0.17-0.67; P<0.05) in comparison with normal pregnancy.

CONCLUSIONS

Endothelial cells from the placental villi are upregulated for expression of Egr-1 transcription factor gene in placental vascular disease. The FGFR-1 activation and increase in FGF-2 in the fetal circulation are known to be very early features of the response of endothelium to injury. Egr-1 is a promoter of many key pathophysiologically relevant target genes, which influence the development of subsequent vascular lesions. This change may occur before the pathological features recognised on microscopy.

Suboptimal neurodevelopment in very preterm infants is related to fetal cardiovascular compromise in placental insufficiency

OBJECTIVE

The purpose of this study was to determine the relationship between fetal cardiovascular hemodynamics and neurodevelopmental outcome in infants born before 32 gestational weeks with placental insufficiency.

STUDY DESIGN

Seventeen fetuses that underwent Doppler ultrasonography within 24 hours before delivery were included in this prospective cross-sectional study. Placental histology was examined. Multiple inflammatory markers and vascular endothelial growth factor (VEGF) and its receptor were analyzed from umbilical cord serum. Neurodevelopmental outcome was assessed by Griffiths scales at 1 year of corrected age.

RESULTS

Infants with suboptimal outcome (n = 7) had higher umbilical artery, ductus venosus, and inferior vena cava pulsatility index values (P < .05) and lower weight-indexed cardiac outputs (P < .05) than infants with normal outcome (n = 10). Placental histology and serum revealed no inflammation. VEGF values were similar among all infants.

CONCLUSION

In placental insufficiency with delivery before 32 gestational weeks, suboptimal neurodevelopment was related to decreased fetal weight-indexed cardiac output and increased systemic venous pressure.

Placental vascular disease and toll-like receptor 4 gene expression

OBJECTIVE

Vascular disease in the placenta, which is identified by the study of umbilical artery Doppler flow velocity waveforms, is associated with endothelial cell activation and a proinflammatory cytokine response in the villous placental circulation. We studied toll-like receptor 4 expression (the ligand is lipopolysaccharide) to examine whether infection may cause these inflammatory components of placental vascular disease through an innate immune response.

STUDY DESIGN

Microvessel endothelial cells were isolated from human placentae with collagenase digestion and then extracted with Dynabeads that were coated with monoclonal antibody against CD31. We studied 13 placentae from normal pregnancies that were delivered at term and 15 pregnancies with umbilical placental vascular disease that was defined by an abnormal umbilical artery Doppler study. We extracted RNA from the isolated endothelial cells. The messenger RNA expression of toll-like receptor 4 production was assessed by reverse transcriptase-polymerase chain reaction and factored relative to the glyceraldehyde-3-phosphate dehydrogenase and 18S ribosomal RNA genes.

RESULTS

Microvessel endothelial cells from placental villi with placental vascular disease showed up-regulation of toll-like receptor 4 expression (toll-like receptor 4/18S, 1.92 +/- 0.37 vs 0.99 +/- 0.19; P < .05; toll-like receptor 4/glyceraldehyde-3-phosphate dehydrogenase, 2.20 +/- 0.36 vs 1.25 +/- 0.22; P < .05) in comparison with normal pregnancy.

CONCLUSION

Up-regulation of toll-like receptor 4 gene in the endothelium of the placental villi is present in placental vascular disease, which may result from exposure of this endothelium to the toll-like receptor 4 ligand lipopolysaccharide in vivo. Directly extracted endothelial cells were used to avoid the possibility for change in behavior in tissue culture. We conclude that Gram-negative infection and lipopolysaccharide stimulation may cause placental vascular disease.

Microvascular endothelial cell activation is present in the umbilical placental microcirculation in fetal placental vascular disease

OBJECTIVE

Fetal growth restriction is associated with an abnormal umbilical artery Doppler study. A vascular disease is present in the fetal umbilical placental microcirculation. We hypothesized that the local production of factors that are injurious to microvessel endothelium is responsible for this vascular disease and that endothelial cell activation is a feature of this. Because the expression of the cell adhesion molecules is associated with endothelial cell activation, we isolated endothelial cells from the microvessels of the umbilical placenta and examined them for evidence of gene expression of cell adhesion molecules.

STUDY DESIGN

Endothelial cells from the microcirculation of human placenta were isolated and purified with collagenase digestion and extraction with superparamagnetic beads that were coated with monoclonal antibody against CD31. Microvessel endothelial cells were isolated from the placentae of 13 women with a normal pregnancy and delivery at term and 10 placentas with umbilical placental vascular disease that was defined by abnormal umbilical artery Doppler study. Total RNA was extracted from isolated endothelial cells. The messenger RNA expressions of cell adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule-1) were assessed by semiquantitative reverse transcription-polymerase chain reaction.

RESULTS

Microvessel endothelial cells from the fetal placentae of pregnancies that were complicated by umbilical placental vascular disease showed an enhanced expression of intercellular adhesion molecule-1 messenger RNA (2.12+/-0.45 vs 0.92+/-0.25) and platelet endothelial cell adhesion molecule-1 messenger RNA (4.29+/-0.87 vs 2.41+/-0.42) in comparison to normal pregnancies. There was no significant difference in expression of vascular cell adhesion molecule-1 messenger RNA (1.55+/-0.37 vs 1.68+/-0.38).

CONCLUSION

We have shown that vascular disease in the fetal umbilical placental circulation is associated with an increase in the expression of intercellular adhesion molecule-1 and platelet endothelial cell adhesion molecule-1 by microvessel endothelial cells. We postulate that locally released factors cause injury and activation to microvessel endothelial cells. In this regard, the process in the fetus is similar to that of atherothrombotic vascular disease of later life.

A proinflammatory cytokine response is present in the fetal placental vasculature in placental insufficiency

OBJECTIVE

Vascular disease in the umbilical placental circulation is associated with fetal growth restriction and adverse outcome. It may be identified antenatally by the study of umbilical artery Doppler flow velocity waveforms. The cause of this vascular disease is unknown. We have previously provided indirect evidence for endothelial cell activation and a proinflammatory cytokine response. Recently, a family of inhibitors of cytokine signaling has been identified, referred to as the suppressors of cytokine signaling (SOCS). Activation of SOCS occurs when cytokines are produced in stimulated cells. We tested the hypothesis that endothelial cell activation was present in umbilical placental vascular disease and was associated with production of proinflammatory cytokines and members of the family of SOCS.

STUDY DESIGN

Placentas were collected at delivery and microvascular endothelial cells were isolated. We studied 13 normal pregnancies and 10 with umbilical placental vascular disease identified by an abnormal umbilical artery Doppler study. Placental pieces were digested with collagenase and purified by adherence to Dynabeads coated with monoclonal antibody against CD31. The RNA was extracted from isolated endothelial cells. The messenger RNA expression of cytokine production (interleukin-6 and interleukin-8) and the members of SOCS family (CIS, SOCS1, SOCS2, and SOCS3) were assessed by use of semiquantitative reverse transcriptase-polymerase chain reaction.

RESULTS

In the microcirculation of the placenta, endothelial cell expression of interleukin-6 messenger RNA (2.50+/-0.60 vs 1.25+/-0.26) and interleukin-8 messenger RNA (2.83+/-0.55 vs 1.58+/-0.27) was up-regulated in umbilical placental vascular disease in comparison to normal pregnancy. The endothelial cell mRNA expression of SOCS2 (3.36+/-0.77 vs 1.76+/-0.29) and SOCS3 (2.77+/-0.60 vs 1.48+/-0.26) was enhanced in placental vascular disease. There was no significant difference in expression of CIS and SOCS1 in microvessel endothelial cells.

CONCLUSION

We have demonstrated that microvessel endothelium of the fetal placental vasculature produces both the proinflammatory cytokines (interleukin-6 and interleukin-8) and members of SOCS family (SOCS2 and SOCS3) in umbilical placental vascular disease. This cytokine production may play a key role in the interaction of endothelial cells of the placenta villi with neighboring cells. The up-regulation of SOCS2 and SOCS3 indicates these are the major negative regulators in umbilical placental microvessel endothelial cell activation pathways. By its occurrence, this also confirms the presence of a proinflammatory cytokine response.

Comprehensive assessment of fetal wellbeing: which Doppler tests should be performed?

PURPOSE OF REVIEW

Doppler applications in pregnancy are expanding exponentially. Flow velocity waveforms provide important information 12 weeks to term, from maternal vessels, placental circulation and fetal systemic vessels, with implications for both mother and fetus. As applications proliferate, awareness of the complexity of fetal and placental circulations, in normal pregnancy and in sequential responses to compromise, has also grown. The necessary data are now available to establish core values in Doppler evaluation for at-risk pregnancies.

RECENT FINDINGS

Uterine arteries depict maternal vascular effects of the invading placenta, predicting the frequency and severity of pre-eclampsia and intrauterine growth restriction. New evidence suggests early treatment based on this principle, significantly reduces these impacts. Umbilical artery Doppler reflects downstream placental vascular resistance, strongly correlated with intrauterine growth restriction and the multisystem effects of placental deficiency. Abnormalities are progressive, with reduction, loss, and finally a reversal of diastolic flow. When umbilical arteries become abnormal, the differentiation of fetal status requires Doppler information from systemic vessels. Middle cerebral artery changes begin when the redistribution of cardiac output reflects rising placental resistance, demonstrating 'brain sparing' when cerebrovascular dilation occurs. In the compromised intrauterine growth retarded fetus, precordial veins illustrate fetal cardiac function, changing as the respiratory status declines. This Doppler information is combined with biophysical profile scoring to determine the need for and timing of intervention.

SUMMARY

Doppler evaluation of at-risk pregnancies provides crucial prognostic and diagnostic detail about placentation and fetal adaptation. What has been research detail is now becoming the standard of care, in comprehensive fetal-maternal assessment.

Fetal plasma stimulates endothelial cell production of cytokines and the family of suppressor of cytokine signaling in umbilical placental vascular disease

OBJECTIVE

We have shown that fetal plasma from pregnancies with placental vascular disease that were identified by an abnormal umbilical artery Doppler study causes endothelial cell activation. We investigated the hypothesis that this would be associated with endothelial cell production of cytokines and their natural regulators, the suppressor of cytokine signaling family. Activation of suppressor of cytokine signaling at the time of cytokine release confirms the fact that cytokine production is occurring in a stimulated cell.

STUDY DESIGN

Aliquots from a common culture of human umbilical vein endothelial cells were incubated with fetal plasma from normal pregnancy (n = 29 pregnancies), from umbilical placental vascular disease defined by abnormal umbilical artery Doppler waveforms (n = 38 pregnancies), and from preeclampsia with normal umbilical artery Doppler scans (n = 10 pregnancies). The expression of messenger RNA for the cytokines interleukin-6 and interleukin-8 and the members of suppressor of cytokine signaling family (cytokine-inducible SH2-containing protein, suppressor of cytokine signaling 1, 2, and 3) were assessed by reverse transcriptase-polymerase chain reaction.

RESULTS

Endothelial cell expression of interleukin-6 messenger RNA (1.94 +/- 0.24 vs 1.31 +/- 0.16) and interleukin-8 messenger RNA (2.62 +/- 0.33 vs 1.64 +/- 0.22) were enhanced in response to incubation with fetal plasma from placental vascular disease in comparison to incubation with fetal plasma from normal pregnancy. The messenger RNA expression of suppressor of cytokine signaling-2 (2.03 +/- 0.23 vs 1.37 +/- 0.16) was up-regulated significantly in placental vascular disease. Differences for cytokine-inducible SH2-containing protein, suppressor of cytokine signaling-1, and suppressor of cytokine signaling-3 were not significant. The expression of cytokines and the suppressor of cytokine signaling family did not differ from normal in the group with maternal preeclampsia and a normal umbilical study. Interestingly, in the umbilical placental vascular disease group, the results were similar in the subgroups, with or without preeclampsia in the mother.

CONCLUSION

We have shown that factors that cause endothelial cell injury are present in the fetal circulation in umbilical placental vascular disease. This study is the first report of cytokine production and release and activation of the suppressor of cytokine signaling family by endothelial cells in response to fetal plasma in placental vascular disease. The role of all members of the suppressor of cytokine signaling family in this process must be investigated further. The fact that both the agonist (cytokines) and the antagonist (suppressor of cytokine signaling-2) are produced points to a significant role of endothelial cells in this disease.

Endothelial cell apoptosis is induced by fetal plasma from pregnancy with umbilical placental vascular disease

OBJECTIVE

Vascular disease in the umbilical placental circulation that is detected by umbilical artery Doppler study is associated with adverse fetal outcome. Endothelial cell activation and platelet consumption are features of this pathologic condition. We postulated that this was due to the local release of factors that cause endothelial cell injury and that these would spill into the fetal circulation. To test this hypothesis, we examined for the presence in fetal plasma of factors that induced endothelial cell apoptosis in pregnancies that were complicated by umbilical placental vascular disease.

STUDY DESIGN

Isolated and cultured human umbilical vein endothelial cells were exposed to fetal plasma from the 3 fetal groups: normal pregnancy (n = 32 patients), pregnancy with umbilical placental vascular disease that was identified by an abnormal umbilical artery Doppler study (n = 38 patients), and pregnancy with maternal preeclampsia and normal umbilical artery Doppler study (n = 16 patients). Early apoptosis can be recognized by a loss of plasma membrane asymmetry with membrane uptake of annexin V. This was measured with annexin V and propidium iodide staining by fluorescent-activated cell scanning. Cells that underwent early apoptosis stained positive for annexin V and negative for propidium iodide (in contrast with cells that underwent necrosis). Cytosolic proteolytic activity was also measured. The lysates from endothelial cells that were stimulated by fetal plasma from umbilical placental vascular disease were tested for caspase-3 and caspase-8 activities by a fluorescent assay with spectrofluorophotometry.

RESULTS

The percentage of endothelial cells that underwent apoptosis was significantly higher (P <.05) when stimulated with fetal plasma from pregnancies with umbilical placental vascular disease (17.71% +/- 1.31%) than with fetal plasma from normal pregnancies (9.76% +/- 0.87%). In the presence of maternal preeclampsia with normal umbilical artery Doppler study, the percent of apoptotic cells (11.31% +/- 1.59%) was similar to that of the normal group. In the group with abnormal umbilical artery Doppler study, there was no difference between pregnancies with preeclampsia (n = 17 pregnancies) and without preeclampsia (n = 21 pregnancies). The protease activity of caspase-3 was significantly enhanced in the group with umbilical placental vascular disease compared with normal pregnancy (0.79 +/- 0.06 vs 0.45 +/- 0.08 microMol/L). However, no difference in caspase-8 activity was detected (0.66 +/- 0.05 vs 0.56 +/- 0.05 microMol/L).

CONCLUSION

Endothelial cell apoptosis is a feature of umbilical placental vascular disease. Our study demonstrates the presence of factors in the fetal plasma that caused endothelial cells to undergo early apoptosis. This increased apoptosis was only seen in the presence of placental vascular disease and was independent of the presence or absence of maternal preeclampsia. Our results indicate that programmed endothelial cell death occurs in the fetal circulation as a part of the injury that is associated with the development of umbilical placental vascular disease. The caspase-3, rather than caspase-8, signal transduction pathway appears to be involved in the mediation of endothelial cell apoptosis that was detected in our study.