Is 8% O2 more normoxic than 21% O2 for long-term in vitro cultures of human primary term cytotrophoblasts?

STUDY QUESTION

Is 8% O2 a better percentage of atmospheric oxygen for long-term cultures of human primary term cytotrophoblasts than the conventional 21% O2 traditionally used in cell culture?

SUMMARY ANSWER

Human primary term cytotrophoblasts are able to differentiate into syncytiotrophoblasts under both atmospheric oxygen levels.

WHAT IS KNOWN ALREADY

Cell culture is traditionally done under 21% O2, which is equal to a pO2 of ~160 mm Hg. Based on the pO2 measured after instauration of the blood circulation within the placenta, it has been proposed that cytotrophoblasts culture should be under 8% O2, which is equivalent to 60 mm Hg, and that this percentage should be considered as the physiological normoxia for cytotrophoblasts.

STUDY, DESIGN, SIZE, DURATION

Cytotrophoblasts were isolated and purified from human term placentas (n > 4). Cells were cultured under 21% O2 and 8% O2 for 12 days. Several cellular parameters were assessed on Days 2, 4, 8 and 12.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Placentas were obtained after vaginal or elective cesarean delivery from uncomplicated pregnancies at term (n ≥ 4). Cell viability was measured by a luminescent assay based on quantitation of the ATP content of living cells. Cell fusion was assessed by quantification of syncytin and e-cadherin mRNA expression by real-time PCR and determination of the fusion index by immunofluorescent microscopy. Trophoblast differentiation was assessed by measuring the expression levels of hCGβ, inhibin α subunit (InhA) and placental growth factor (PlGF) by real-time PCR and ELISA. Finally, the effect of the two oxygen levels on apoptosis and cellular oxidative stress was also investigated by quantifying caspase 3/7 activation, superoxide dismutase 1 (SOD-1) mRNA expression and H2O2 generation.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no difference between 21% O2 and 8% O2 on cell viability. Cell fusion seemed to be enhanced during the first 4 days when the cells were cultured under 21% O2 compared to 8% O2. The expression level of hCGβ was equivalent in both oxygen conditions, indicating that there was no difference in trophoblast differentiation. Interestingly, InhA expression was higher under 8% O2, while PlGF expression was inhibited compared to 21% O2. This latter result indicates that 8% O2 may be more hypoxic than normoxic for in vitro culture of primary term cytotrophoblast. This is further corroborated by the fact that 21% O2 did not significantly increase caspase 3/7 activities and the oxidative stress (SOD-1 mRNA expression and H2O2 generation) in our cell cultures.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

The in vitro culture of cytotrophoblasts is artificial and does not reflect the in vivo situation. The cell population is nearly 100% pure, cultured as a monolayer, and the cells bath in a chemically defined culture medium deprived of any oxygen carrier. The oxygen molecules available to the cells are passively dissolved in the medium. The gas dissolution properties of the medium and the cellular consumption rate of oxygen may allow the cells to sustain a wide range of oxygen percentages from 8% to 21%.

WIDER IMPLICATIONS OF THE FINDINGS

It is possible to culture human primary term cytotrophoblasts for at least 12 days. The O2 percentage of the air does not negatively affect in vitro cytotrophoblast differentiation. For in vitro culture of cytotrophoblasts, it is not necessary to lower the percentage of atmospheric oxygen to 8%.

STUDY FUNDING/COMPETING INTEREST(S)

This work was fully supported by 'Fetus for Life' charity. The authors state that there is no conflict of interest to declare regarding the publication of this paper.

HIF1A and EPAS1 potentiate hypoxia-induced upregulation of inhibin alpha chain expression in human term cytotrophoblasts in vitro

Study Question

Are hypoxia-inducible factors (HIF) responsible for the potentiation of inhibin alpha subunit (INHA) gene expression in primary cultures of human term cytotrophoblasts under low-oxygen tension?

Summary Answer

Both HIF1A and endothelial PAS domain protein 1 (EPAS1) are involved in the potentiation of INHA gene upregulation in cytotrophoblasts cultured under hypoxia.

What Is Known Already

During the in vitro differentiation of cytotrophoblasts into syncytiotrophoblasts under 21% O2, INHA expression increases. This expression is further increased when cells are cultured under low-oxygen tension (e.g. 2.5% O2). Moreover, in pregnancy-related diseases, such as pre-eclampsia or intrauterine growth restriction (IUGR), in which hypoxia is suspected to be responsible for the abnormal placental development, maternal serum concentration of inhibin A is elevated.

Study Design, Size, Duration

Cytotrophoblasts were isolated and purified from human term placentas (n = 6). Cells were cultured under 21% O2, and allowed to differentiate for 48 h. A first group of cells was treated for 16 h under 21% O2 with dimethyloxalylglycine (DMOG) or deferoxamine (DFX), molecules that mimic hypoxia by inhibiting HIF1 proteasomal degradation. Involvement of HIF1A and EPAS1 (also known as HIF2A), two HIF isoforms expressed in trophoblasts, was shown by treating another group of cells cultured under 2.5% O2 with specific inhibitors of HIF1A and EPAS1 for 16 h. INHA mRNA expression was assessed by real-time PCR and secreted inhibin A was quantified by ELISA. The role of HIF1A and EPAS1 in INHA transcriptional regulation was further confirmed by cotransfecting primary cytotrophoblasts with a luciferase reporter plasmid containing a 3.9 kb INHA promoter and plasmids allowing overexpression of HIF1A and EPAS1.

Participants/Materials, Setting, Methods

Placentas were obtained after vaginal or elective cesarean delivery from uncomplicated pregnancies at term (n≥ 4). The methods used were hormone measurements in the cell supernatants by enzyme-linked immunosorbent assay, real-time quantitative PCR, western blotting, immunofluorescence microscopy and transient transfection.

Main Results and the Role of Chance

HIF1 protein stabilization with DMOG and DFX increased 21% O2-induced INHA mRNA and protein upregulation (P < 0.05 versus control), while hypoxia-induced INHA upregulation was repressed by HIF1A and EPAS1 inhibitors (P < 0.05 versus control). In transfection experiments of primary term cytotrophoblasts, cloned INHA promoter transcriptional activity was increased by 2.5% O2 compared to 21% O2 (P < 0.05). Overexpression of both HIF1A and EPAS1 under 21% O2 increased cloned INHA transcriptional activity (P < 0.001 versus control).

Large Scale Data

Not applicable.

Limitations, Reasons for Caution

HIF1A and EPAS1 may regulate INHA expression by binding to an hypoxia-responsive element within the promoter, but we were unable to identify such an element. Inhibition of HIF1A and EPAS1 did not completely suppress upregulation of INHA expression suggesting that other transcription factors, not identified or studied here, are involved.

Wider Implications of the Findings

Our data suggest that the effect of HIF1 proteins on INHA gene promoter activity may be indirect. By demonstrating the role of HIF1A and especially EPAS1 in INHA gene upregulation under hypoxia, the results suggest that HIF1 proteins may become new therapeutic targets in the treatment of pregnancy-related diseases such as pre-eclampsia or IUGR.

Study Funding/Competing Interest(s)

This work was fully supported by 'Fetus for Life' charity. C. Depoix was supported by a fellowship 'Fonds de Recherche Clinique' from 'Fondation Saint-Luc', Belgium. The authors declare that there is no conflict of interest regarding the publication of this paper.

Reversible effects of oxygen partial pressure on genes associated with placental angiogenesis and differentiation in primary-term cytotrophoblast cell culture

Timely regulated changes in oxygen partial pressure are important for placental formation. Disturbances could be responsible for pregnancy-related diseases like preeclampsia and intrauterine growth restriction. We aimed to (i) determine the effect of oxygen partial pressure on cytotrophoblast differentiation; (ii) measure mRNA expression and protein secretion from genes associated with placental angiogenesis; and (iii) determine the reversibility of these effects at different oxygen partial pressures. Term cytotrophoblasts were incubated at 21% and 2.5% O2 for 96 hr, or were switched between the two oxygen concentrations after 48 hr. Real-time PCR and enzyme-linked immunosorbent assays (ELISAs) were used to evaluate cell fusion and differentiation, measuring transcript levels for those genes involved in cell fusion and placental angiogenesis, including VEGF, PlGF, VEGFR1, sVEGFR1, sENG, INHA, and GCM1. Cytotrophoblasts underwent fusion and differentiation in 2.5% O2 . PlGF expression was inhibited while sVEGFR1 expression increased. VEGF and sENG mRNA expressions increased in 2.5% compared to 21% O2 , but no protein was detected in the cell supernatants. Finally, GCM1 mRNA expression increased during trophoblast differentiation at 21% O2 , but was inhibited at 2.5% O2 . These mRNA expression effects were reversed by returning the cells to 21% O2 . Thus, low-oxygen partial pressure does not inhibit term-cytotrophoblast cell fusion and differentiation in vitro. Lowering the oxygen partial pressure from 21% to 2.5% caused normal-term trophoblasts to reversibly modify their expression of genes associated with placental angiogenesis. This suggests that modifications observed in pregnancy diseases such as preeclampsia or growth retardation are probably due to an extrinsic effect on trophoblasts.

Two-year neonatal outcome following PPROM prior to 25 weeks with a prolonged period of oligohydramnios

BACKGROUND

Improved neonatal survival data have been reported following early preterm prelabour rupture of membranes (PPROM) prior to 25 weeks gestation with a prolonged latency to delivery and persistent oligohydramnios. However, data regarding long-term respiratory and neurological morbidity are lacking.

AIMS

To evaluate the respiratory and neurological outcome data at two years of age in a cohort of infants born following PPROM prior to 25 weeks with a prolonged latency (14 days) to delivery and compare the data to an aged matched group of infants.

METHODS

Retrospective case note analysis over a 43-month period at Saint Luc University Hospital, Brussels.

RESULTS

15 surviving infants born following PPROM were matched to a group of 30 control infants. Although there was no significant difference in the incidence of BPD between the groups (33% vs 27%, p=0.24), the length of hospitalisation, duration of respiratory support and number of hospital readmissions for respiratory indications were all significantly higher for infants born following a prolonged period of oligohydramnios. There were no major anomalies on cranial ultrasound in the PPROM group and Baileys developmental assessment at 20-24 months corrected gestational age showed no difference between the two groups (Mental development index 93.9 vs 94.4 and Psychomotor development index 95.5 vs 95.8 respectively p = ns).

CONCLUSION

Neurodevelopmental outcome appears encouraging in this cohort although these infants are at high risk of prolonged initial hospitalisation and significant respiratory morbidity in the first two-years of life.

[Screening strategy and diagnostic criteria for gestational diabetes. Proposals of the GGOLFB]

For nearly 50 years, the strategy of screening and the diagnostic criteria for gestational diabetes have been the subject of endless controversies. They differ between countries and from one center to another, mainly because of the lack of hard data allowing to define glycemic thresholds at which a therapeutic management is needed. Recently, a large observational study has demonstrated the existence of a robust relationship between maternal blood sugar and several fetomaternal perinatal complications. This relationship is linear, with no clear threshold that would define gestational diabetes unambiguously. Meanwhile, two randomized intervention trials have shown that the therapeutic management of mild gestational diabetes was associated with improved perinatal outcomes. Based on these data, the "International Association of Diabetes and Pregnancy Study Group" (IADPSG) released new recommendations on screening methods and diagnostic criteria for gestational diabetes. Although already endorsed by several international associations and implemented in some countries, these recommendations still raise questions and criticisms. This is why the "Groupement des Gynécologues Obstétriciens de Langue Française de Belgique" (GGOLFB) organized a meeting between diabetologists and gynecologists which allowed to reach a consensus on the strategy that we intend to implement in our respective centers. The purpose of this paper is to briefly overview the recent advances in gestational diabetes and more particularly to make our key conclusions known to the medical community. This will enable the standardization of the management of gestational diabetes in the French-speaking part of Belgium.

[Screening strategy and diagnostic criteria for gestational diabetes. Proposals of the GGOLFB]

For nearly 50 years, the strategy of screening and the diagnostic criteria for gestational diabetes have been the subject of endless controversies. They differ between countries and from one center to another, mainly because of the lack of hard data allowing to define glycemic thresholds at which a therapeutic management is needed. Recently, a large observational study has demonstrated the existence of a robust relationship between maternal blood sugar and several fetomaternal perinatal complications. This relationship is linear, with no clear threshold that would define gestational diabetes unambiguously. Meanwhile, two randomized intervention trials have shown that the therapeutic management of mild gestational diabetes was associated with improved perinatal outcomes. Based on these data, the " International Association of Diabetes and Pregnancy Study Group "(IADPSG) released new recommendations on screening methods and diagnostic criteria for gestational diabetes. Although already endorsed by several international associations and implemented in some countries, these recommendations still raise questions and criticisms. This is why the "Groupement des Gynécologues Obstétriciens de Langue Française de Belgique " (GGOLFB) organized a meeting between diabetologists and gynecologists which allowed to reach a consensus on the strategy that we intend to implement in our respective centers. The purpose of this paper is to briefly overview the recent advances in gestational diabetes and more particularly to make our key conclusions known to the medical community. This will enable the standardization of the management of gestational diabetes in the French-speaking part of Belgium.

Dissection d’un anévrysme de l’artère rénale chez une femme enceinte atteinte de maladie Elhers-Danlos de type IV

Recall the clinical signs and personal and family medical history suggestive of Elhers-Danlos syndrome, mainly type IV. Review of literature and presentation of a clinical case observed in a female patient with Elhers-Danlos disease type IV who developed dissection of a renal artery during pregnancy. The prevalence of the syndrome is increasing, reaching, according to the latest publications 1/5,000 births. It is important to determine the type of syndrome to assess prognosis. In the classic type and in the hyper mobile type, pregnancy is generally well tolerated although certain complications linked to connective tissue dysfunction such as pelvic instability, premature delivery, bleeding postpartum and perineal lacerations, may develop. Ehlers-Danlos syndrome can be associated with serious and even fatal complications for these patients: vascular dissection or uterine rupture. It is important for obstetricians to be aware of the clinical signs and symptoms suggestive of Elhers-Danlos syndrome in a pregnant patient and to know the diagnostic possibilities and potential risks. If a typeIV syndrome is diagnosed, it is very important to inform the patient about the potential implications for pregnancy and maternal health, as well as the risk of transmission to the child and the possibility of antenatal diagnosis.

Activin receptor expression and induction of apoptosis in rat blastocysts in vitro

BACKGROUND

Apoptosis, a process of normal embryonic development, is enhanced in blastocyst from diabetic rats. Nevertheless, glucose seems not to be the only factor involved. Activin A, a TGF-beta family member, is also increased in maternal serum from diabetic pregnancy.

METHODS

Flushing medium, blastocysts and uterine cells were obtained from 5 day old pregnant rats. The presence of activin A in flushing medium was investigated by western blotting. RT-PCR was used to test for the presence of activin betaA subunit mRNA in cultured uterine cells. Blastocysts were stained by immunohistochemistry for activin receptor types IIA and IIB, and chromatin degradation (apoptosis) was investigated by terminal transferase-mediated dUTP nick end labelling in blastocysts exposed in vitro to activin.

RESULTS

In this study, we demonstrate the presence of activin A protein in fluid from rat uterine horns at day 5 of pregnancy, as well as the presence of activin A receptors type IIB in the trophectoderm and inner cell mass and activin A receptor type IIA in trophectoderm cells only. Activin A increases the chromatin degradation level in vitro.

CONCLUSIONS

Activin A protein was found in fluid from uterine horns, and mRNA expression of betaA activin subunit in cultured uterine cells suggests probable secretion from decidual cells. Moreover, activin A increases specifically the apoptosis level in rat blastocyst in vitro.

Seroepidemiology of Herpes Simplex Type 2 in Pregnant Women in Belgium

OBJECTIVE

The objective of this study was to study the prevalence of herpes simplex virus (HSV) type 2 in pregnant women in Belgium.

STUDY DESIGN

The serum of 1000 consecutive women was collected. HSV-1 and HSV-2 control sera were added to the study. HSV-2 antibodies were tested with the HerpeSelect 2 enzyme-linked immunosorbent assay (ELISA; Focus) based on the use of the recombinant gG-2 antigen.

RESULTS

The 21 HSV-2 control subjects were positive. Among the HSV-1 control subjects, 18 were negative and 4 were positive. Among the pregnant women, 80.3% were negative, 1.5% had equivocal results, and 18.2% were positive. No statistical difference was observed according to the origin (European or African) of the women.

CONCLUSIONS

The results obtained with the control sera indicate a high sensitivity of the Focus ELISA, as well as a capacity to discriminate between HSV-1/HSV-2 infection. The HSV-2 prevalence in the studied population raises the question of the possible benefit of a specific preventive program in pregnant women.

Anticytomegalovirus IgG avidity in pregnancy: a 2-year prospective study

OBJECTIVES

To analyze the practical use of the anticytomegalovirus IgG avidity and its impact on the follow-up of pregnancy. To evaluate the performance of IgG avidity to exclude the risk of congenital infection.

METHODS

409 IgM-positive women without a documented seroconversion were prospectively followed. Data concerning the follow-up of the pregnancies were collected (amniotic fluid puncture and samples from the offspring). These observations were compared to those of 76 seroconversions during the same period.

RESULTS

High avidity excluding a primary infection within the past 3 months was observed in 270 women. As the gestational age was less than 3 months for 121 women, exclusion of a primary infection was achieved in 30% of the cases. The rate of amniotic fluid puncture was influenced by the serological result: high avidity (9%), low avidity (42%) and seroconversion (65%).

CONCLUSIONS

A high avidity index during the first trimester of pregnancy could reasonably be considered as a good indicator of past infection and invasive prenatal diagnosis is not necessary. Nearly 70% of the IgM-positive women could be reassured if the first serology was systematically performed before 12 weeks of gestation.

Vascular endothelial growth factor and placenta growth factor concentrations in Down's syndrome and control pregnancies

Vascular endothelial growth factor (VEGF) and placenta growth factor (PLGF) are considered to play important roles in angiogenesis and vascular permeability during placental development. Since trisomy 21 placentae show trophoblastic hypoplasia and hypovascularity, we investigated PLGF and VEGF synthesis in Down's syndrome pregnancies. Maternal serum was collected from 102 euploid and 24 trisomy 21 pregnancies between 15 and 20 weeks gestation and tested for these two factors by enzyme-linked immunosorbent assays. Protein extracts from 15 normal and six trisomy 21 placentae were also tested. VEGF was not detected in maternal serum, while PLGF increased significantly with gestational age. Serum PLGF, transformed as a multiple of the gestational age median (MoM), in Down's syndrome pregnancies was significantly lower than in euploid controls (mean 0.67 +/- 0.043 MoM versus 1.00 +/- 0.047 MoM, analysis of variance F = 11.605, P < 0.001 ). Both VEGF and PLGF were detected in placental protein extracts without variation according to gestational age. Down's syndrome placentae had significantly less PLGF compared to normal placentae (Mann-Whitney, P < 0.05 ) but no difference was observed in placental VEGF content (Mann-Whitney, P = 0.94 ). Considering the biological properties of PLGF, this decrease may provide new insights into the mechanism(s) leading to the structural and functional anomalies described in trisomy 21 placentae.

Twin-to-twin transfusion syndrome: treatment by amniodrainage and septostomy

OBJECTIVE

Severe previable twin-to-twin transfusion syndrome (TTTS) is associated with a high fetal loss rate and is therefore usually treated. In this paper, serial amniodrainage and inter-twin septostomy are reviewed in terms of technical aspects and fetal outcome.

STUDY DESIGN

A review of the literature using a MEDLINE DATA search between 1990 and 2000 was done in order to describe the mechanisms and technical aspects of both procedures with their physiopathological consequences. In addition, data from our experience with septostomy are given.

RESULTS

Amniodrainage increases survival rate, with outcome ranging from 40 to 87% (mean: 56%). Inter-twin septostomy is associated with a mean fetal survival rate ranging from 57 to 83% (mean: 70%).

CONCLUSION

In severe TTTS, amniodrainage and septostomy are simple therapeutic alternatives with a survival rate similar to what is currently reported for laser coagulation of placental vessels.

Multiple screening for fetal Down's syndrome with the classic triple test, dimeric inhibin A and ultrasound

The aim of the study was to determine whether inhibin combined with ultrasound improves the classic second trimester triple test. Eighteen Down's syndrome and 200 euploid pregnancies were included. Maternal serum alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and estriol (E3), measured between 15 and 20 weeks' gestation by radioimmunoassay, were retrieved. Inhibin A was tested with a specific two-monoclonal-antibody ELISA. Ultrasound was performed between 15 and 25 weeks' gestation: femur length, nuchal thickness and morphological abnormalities were assessed. Statistical analysis used a multivariate discriminant analysis. Except for the classic triple test parameters, only inhibin and the standard deviation score (SDS) for femur length allowed us to make a statistically significant distinction between euploid and Down's syndrome pregnancies. For a 5% false-positive rate, the classic triple test sensitivity was 61%. When E3 was replaced with inhibin A, the sensitivity increased to 77.8% and to 66.7% with SDS femur length. Combining hCG, AFP, SDS femur length and inhibin A gave a sensitivity of 66.7% for a false-positive rate of 2.5%. In conclusion, the classic triple test can be more significantly improved by replacing E3 with inhibin than by including ultrasound. However, a combination of ultrasound and inhibin enhances both the sensitivity and specificity of the test. In Down's syndrome screening, the biological parameters improve sensitivity while ultrasound is a better indication of specificity.

Conservative management of triplet pregnancy after delivery of one foetus

This paper intends to demonstrate that the conservative management of triplet pregnancy after delivery of one foetus is a feasible and reasonable approach. Three cases of triplet pregnancy with successful conservative management after miscarriage of one foetus, are presented and compared with cases in the literature. The route of delivery, as well as the role of tocolysis, cerclage, prophylactic antibiotic therapy and corticosteroids are discussed. Guidelines for conservative treatment are proposed. The deliveries of our three pregnancies were delayed by 63, 44 and 22 days respectively. Foetal and neonatal evolution are normal in five of the remaining foetuses. Only one intrauterine death is observed. No maternal complications with sequelae are reported. After abortion of the first triplet, contractions often persist and the birth of the two remaining foetuses may be unavoidable. Nevertheless, in our experience, confirmed by some reports in the literature, prolongation of the pregnancy after expulsion of the first foetus is possible. It can be achieved by cervical cerclage associated with tocolytic and antibiotic therapy. This management is not associated with significantly increased foetal-maternal morbidity.

Gonadotropins, prolactin, inhibin A, inhibin B, and activin A in human fetal serum from midpregnancy and term pregnancy

Using specific enzyme-linked immunosorbent assays we measured inhibin A, inhibin B, and activin A in relation to LH, FSH, and PRL in normal human fetal midpregnancy serum obtained by in utero cord venipuncture (n = 25) and compared these results to those in fetal serum from term pregnancies (n = 23). We also tested serum from fetuses with intrauterine growth retardation (n = 6) or trisomy 21 (n = 6). We found no measurable inhibin A, except in three midpregnancy males (3 of 14). Inhibin B, however, was detected in midpregnancy male fetuses (167+/-67 pg/mL) and was higher than that in females (16+/-12 pg/mL). It was present in male term fetuses (125+/-32 pg/mL), but not in females. The activin A levels did not significantly differ between term and midpregnancy males and females. LH and FSH were detected in midpregnancy male fetuses (4.4+/-3.3 and 0.77+/-0.49 mIU/mL, respectively), with higher levels in females (33.0+/-23.2 and 54.4+/-27.7 mIU/mL, respectively), and were suppressed at term. PRL did not exhibit sexual difference, but showed a higher level at term (322.4+/-113.8 ng/mL) than at midpregnancy (33.0+/-26.1 ng/mL). Comparison of inhibin B with FSH levels showed correlation coefficients of -0.565 at midpregnancy vs. +0.445 at term. Serum from fetuses with intrauterine growth retardation or trisomy 21 did not show any different hormonal profiles. These data suggest that inhibin B is probably an additional factor in FSH inhibition at midpregnancy, whereas activin A is not associated with any change in the different studied populations. We speculate that inhibin A could be a method to detect maternal blood contamination in cord venipuncture.

Increased risk of cytomegalovirus transmission in utero during late gestation

OBJECTIVE

To determine whether the rate of human cytomegalovirus transmission in utero is related to the gestational age at the time of maternal infection.

METHODS

One hundred twenty-three pregnant women followed in our units between 1988 and 1998 were studied retrospectively. Each had developed a primary infection with cytomegalovirus evidenced by a seroconversion, confirmed by specific enzyme immunoassays. Infants were diagnosed by urine culture.

RESULTS

Regardless of gestational age at the time of maternal cytomegalovirus seroconversion, the mean rate of intrauterine transmission was 57.5%. There was a statistically significant difference between early seroconversion (during the first trimester) and late seroconversion (during the third trimester) (36.0% versus 77.6%; P < .001). The risk of transmission calculated for seroconversion during the second trimester was intermediate (44.9%).

CONCLUSION

A statistically significant difference in the rate of intrauterine cytomegalovirus transmission was observed according to the duration of pregnancy at which primary infection occurred. The rate of transmission increased with gestational age.

Prenatal diagnosis of human cytomegalovirus by culture and polymerase chain reaction: 98 pregnancies leading to congenital infection

Human cytomegalovirus (HCMV) is the most common cause of viral intra-uterine infection. The experience with prenatal diagnosis remains limited and is based on few reports of small numbers of cases. It is thus difficult to compare the accuracy of the different tests because the groups studied were small and heterogeneous. We describe here our experience on a series of 98 pregnancies leading to HCMV congenital infection, among which 71 have been tested by amniotic fluid (AF) sampling followed by culture and/or polymerase chain reaction (PCR). Independently of the delay between AF sampling and the first HCMV IgM positive result, the mean sensitivity of both culture and PCR was around 70 per cent. The best sensitivity (95.5 per cent) was obtained after a delay > or = 6 weeks in late pregnancy (> or = 23 weeks). The present study demonstrated clearly that the delay between AF puncture and the presumed date of seroconversion is more important for sensitivity than the technique used for the diagnosis (PCR or culture). However, even in the best diagnostic conditions, negative results of HCMV culture or PCR in AF cannot formally exclude intra-uterine infection.

Very long chain acyl-coenzyme A dehydrogenase deficiency in two siblings: evolution after prenatal diagnosis and prompt management

A boy had neonatal seizure, lethargy, and metabolic acidosis at presentation. He recovered completely, but the recurrence of a similar episode with associated cardiomyopathy and dicarboxylic aciduria at 10 months of age led to the recognition of a fatty acid oxidation defect. A diagnosis of very long chain acyl-coenzyme A dehydrogenase deficiency was later made by enzyme assay in culture fibroblasts from this child, as well as in cultured amniotic cells from a sibling fetus. This prenatal diagnosis forestalled neonatal injury by close clinical and metabolic monitoring of the second infant. Early diagnosis and management should potentially improve the generally poor prognosis for patients with very long chain acyl-coenzyme A dehydrogenase deficiency.

First-trimester diagnosis of conjoined twins

Two cases of conjoined twins were diagnosed during first-trimester endovaginal ultrasound and were confirmed by embryoscopy performed prior to the termination of pregnancy. An early and accurate diagnosis of this anomaly, obtained by the combined use of ultrasound and endoscopy, may enable adequate counselling and an earlier termination of pregnancy associated with minimal maternal risks.

Fetal liver hemangioma and chorioangioma: two unusual cases of severe fetal anemia detected by ultrasonography and its perinatal management

Severe anemia was diagnosed by cordocentesis in two fetuses, one with a large chorioangioma, the other with a liver hemangioma. Despite the presence of a chronic fetotumoral shunt, both cases were partly treated by a fetal intravascular transfusion, followed by an elective Cesarean section. This 'predelivery' management of anemia should improve neonatal morbidity associated with severe hematological and acid-base balance disorders.

Carbohydrate metabolism in fetuses with Rh alloimmunization

Glucose, insulin, glucagon and fructosamine were measured in the plasma of control (n = 34) and of Rh fetuses (n = 22) before the first and subsequent transfusion. Prior to treatment, Rh fetuses, compared to controls, had raised concentrations of glucose (p = 0.01), glucagon (p = 0.04) and fructosamine (p = 0.004). Fetal insulin levels were not significantly different. Before subsequent transfusion, despite correction of anemia, Rh fetuses were clearly hyperinsulinemic even after correction for gestation (p = 0.002) and had low glucagon concentrations (p = 0.01) when compared with values at the first transfusion. This metabolic milieu appears similar to that of fetuses of diabetic mothers which have increased plasma glucose and insulin during most of the last third of gestation.

Endocrine pancreatic function in growth-retarded fetuses

Maternal-fetal glucose gradient and fetal plasma glucose, insulin, and glucagon were measured in 63 fetuses: 34 controls and 29 with growth retardation (nine with and 20 without end-diastolic frequencies in the umbilical artery). Maternal-fetal glucose gradient and fetal glucagon levels were higher in the growth-retarded group than in controls (P less than .001), whereas fetal insulin and glucose concentrations were lower (P less than .001). Although maternal-fetal glucose gradient, fetal glucose, and insulin concentrations were similar among the growth-retarded fetuses, fetuses without end-diastolic frequencies in the umbilical artery had higher fetal glucagon levels (P = .01) than those with end-diastolic frequencies. In growth-retarded fetuses, the increase in fetal glucagon might reflect a compensatory response to hypoglycemia and appears to be a better index of fetal compromise than is glucose or insulin.

Effects of fetal intravenous glucose challenge in normal and growth retarded fetuses

Fetal intravenous glucose challenge test (0.75 g/kg of estimated fetal weight) was performed at 26-33 weeks gestation in 9 patients undergoing fetal blood sampling (FBS) by ultrasound guided needling from the umbilical vein. The indication for FBS was rapid karyotyping for fetal malformations in 5 (control group) and severe intrauterine growth retardation in the remaining 4 (IUGR group). Fetal blood samples were taken before the glucose infusion and after 1, 3, 5, 10 and 15 min; glucose and insulin were assayed on each occasion and acid-base balance at 0 and 5 min. Basal fetal pO2, pH, glucose and insulin were lower in the IUGR group than in controls. Following the glucose challenge, fetal glucose levels were similar in the two groups, but in the IUGR group the latter part of the glucose curve was characterized by a slower and delayed return to basal levels. In control fetuses the insulin response following the glucose challenge peaked at 3 min while in IUGR no change in insulin concentration was detected. Fetal pO2 did not change in either group; the median change in fetal pH was significantly different between the two groups (controls: +0.01; IUGR: -0.04; P less than 0.05) and there was a significant correlation between basal pO2 and the change in fetal pH (r = 0.79) (P less than 0.02). These results support the concept of a low energy state in IUGR. Fetal glucose supplementation in IUGR is unlikely to be of benefit and may even exacerbate underlying acidosis.

Fetofetal transfusion syndrome: do the neonatal criteria apply in utero?

Thirteen fetuses (five twin, one triplet) were compromised by fetofetal transfusion syndrome in six pregnancies, five in the mid trimester, and one in the third trimester. This diagnosis, which was suspected because of ultrasound findings of discordant growth, discordant amniotic fluid volumes, concordant external genitalia, and monochorial placentation, was confirmed postnatally in each. Nine fetuses underwent blood sampling to aid diagnosis and assessment of fetal wellbeing. In contrast to fetofetal transfusion syndrome investigated postnatally, a difference in haemoglobin concentration of 50 g/l or more in utero was found in only one pregnancy, which was near term, although all had fetal erythroblastaemia and a difference in weight of 20% or more. In vivo confirmation of shared circulation was achieved in two pregnancies by transfusing adult Rh negative red cells into the smaller fetus and then detecting them by Kleihauer testing in blood aspirated from the larger. Invasive procedures also yielded information on fetal blood gas measurements (acidaemia in four and hypoxaemia in six) and amniotic pressure (raised in two). We suggest that comparison of haemoglobin concentrations is inaccurate in fetofetal transfusion syndrome in utero, the diagnosis of which may necessitate detection of a shared circulation using a marker such as adult red cells.

Maternal-fetal glucose gradient in normal pregnancies and in pregnancies complicated by alloimmunization and fetal growth retardation

Maternal and fetal glucose concentrations were measured simultaneously in 54 pregnancies in which fetal blood sampling was conducted between 18 and 34 weeks gestation. Twenty-five pregnancies were normal (group 1), 13 were complicated by fetomaternal alloimmunization (group 2), and 16 by intrauterine growth retardation (group 3). The maternal glucose concentration was similar in the three groups. The fetal glucose level was significantly lower in growth-retarded (mean = 2.7 mmol/L) than in normal pregnancies (mean = 3.5 mmol/L). There was a statistically significant gradient between maternal and fetal glucose concentrations in groups 1 and 3, but no gradient was found in group 2. Maternal and fetal glucose concentrations were significantly correlated in all groups, but the correlations were distinct. For a given maternal glucose concentration, fetal glucose was higher in patients with alloimmunization and lower in patients with intrauterine growth retardation than in normal pregnancies. In patients with intrauterine growth retardation, fetal PO2 correlated positively with fetal glucose and inversely with maternal fetal glucose gradient.

Fetal hyperinsulinism in anencephaly

Insulin was measured in the blood collected in utero from three midtrimester anencephalic fetuses. The hyperinsulinism found could be due to an underutilization of glucose in the absence of most of the brain and could be responsible for the relatively normal growth in anencephaly despite the absence of the hypothalamohypophysial axis.

Intrauterine manometry: technique and application to fetal pathology

A technique is described for measuring pressure within the amniotic cavity and within fetal vessels and/or body compartments. Two saline-filled catheters were connected at one end to needles inserted during indicated invasive procedures and at the other to silicon strain gauge transducers. In 36 pregnancies with normal liquor volume, stable intra-amniotic pressure (IAP, range 1-14 mmHg) increased with gestation (r = 0.48, p less than 0.01). In pregnancies complicated by severe oligohydramnios, IAP was less than or equal to 1 mm Hg and rose to normal levels with saline amnioinfusion. Raised IAP (range 17-26 mm Hg), found in pregnancies with gross polyhydramnios, fell with drainage of amniotic fluid. Subtraction manometry was used to determine supra-amniotic pressure within the intervillus space, umbilical vein, umbilical artery, abdominal and thoracic cavities, and the urinary tract in normal and/or pathological fetuses. Low intravesical and intrapelvicalyceal pressures (median 6.5, range 2-10 mm Hg) were noted in fetuses with obstructive uropathies. Intrauterine subtraction manometry appears to be a useful tool in the understanding of fetal pathophysiology and may be of clinical benefit in the therapeutic drainage and infusion of amniotic fluid and in the assessment of certain fetal disease states.

Visualization of fetal intra-abdominal organs in second-trimester severe oligohydramnios by intraperitoneal infusion

Fetal intraperitoneal infusion of saline was performed in two patients with severe oligohydramnios at 24 and 25 weeks' gestation in order to enhance visualization of intra-abdominal organs. Renal agenesis was easily diagnosed. The technique can be considered as an alternative to artificial instillation of amniotic fluid in the differential diagnosis of conditions associated with severe oligohydramnios.

The fetal intrahepatic umbilical vein as an alternative to cord needling for prenatal diagnosis and therapy

Seventy-one fetal blood samplings (FBS) were attempted from the intrahepatic portion of the umbilical vein (IHV) at 18-34 weeks; 54 were attempted primarily and 17 secondarily after a failed attempt at the placental cord insertion. Fetal blood was obtained in 89 per cent of the cases. Intravascular transfusion (IVT) was attempted on 31 occasions and successful in 24 (77 per cent). In all cases of failed sampling or transfusion via the IHV, prenatal diagnosis and/or therapy was accomplished using alternative procedures. On only one occasion was the procedure postponed. There were no losses or neonatal morbidity attributable to the procedure. FBS from the IHV may be considered as an alternative approach to sampling the placental cord insertion. It is recommended in cases where the approach to the placental cord insertion is difficult or hazardous.

Changes in fetal acid base status during intravascular transfusion

Umbilical venous pH, PCO2, PO2, and base excess was measured immediately before and after 72 intravascular transfusions in 34 fetuses with erythroblastosis fetalis. In 67 uncomplicated transfusions, infused adult blood led to a mean (95% confidence intervals) fall in pH (0.037, CI 0.029 to 0.044) and base excess (2.03, CI 1.61 to 2.45) and a mean rise in PCO2 (0.24 kPa, CI 0.13 to 0.35). These changes correlated significantly with the increase in fetal haemoglobin and packed cell volume. Five transfusions were associated with complications within six hours: intrauterine death in two, fetal-distress necessitating delivery in two, and preterm labour in one. Two had pre-existing acidosis, whereas two of the three with normal blood gas and acid base measurements before transfusion had acute changes that were outside the normal ranges that had been established in uncomplicated transfusions.

Impairment of insulin release by methylation inhibitors

The possible participation of enzymatic methylation reactions in the process of insulin release was investigated in rat pancreatic islets. The combination of 3-deazaadenosine and DL-homocysteine impaired the incorporation of 3H-methyl from L-[methyl-3H]methionine into endogenous islet proteins and phospholipids, but failed to affect turnover in the phosphatidylinositol cycle. The inhibitors of methylation decreased insulin release evoked by D-glucose or the combinations of D-glucose and gliclazide, L-leucine and L-glutamine, or Ba2+ and theophylline. The inhibitors of methylation did not impair either the oxidation of D-glucose or affect its capacity to decrease K+ conductance, stimulate Ca2+ inflow and provoke 45Ca accumulation in pancreatic islets. It is proposed that, in the process of insulin secretion, a methyl acceptor protein and/or phospholipid play(s) a limited modulatory role in the coupling of cytosolic Ca2+ accumulation to exocytosis.

Sorbitol content of plasma and erythrocytes during induced short-term hyperglycemia

Plasma glucose concentration was increased from a mean basal value of 3.3 +/- 0.1 to 13.3 +/- 1.5 mmol/L by the intravenous administration of glucose for 60 minutes to four healthy volunteers. The sorbitol content of erythrocytes was increased during the period of hyperglycemia from a mean basal value of 65 +/- 9 to 106 -/+ 6 mumol/L. The plasma sorbitol concentration remained constant at 12 +/- 1 mumol/L. This dissociated response indicates that the plasma concentration of sorbitol is not significantly affected by a short-term hyperglycemia sufficient to cause intracellular sorbitol accumulation.