Chorionic villus sampling and materno-fetal transfusions: an immunological pathogenesis of vascular disruptive syndromes?

The cooperative function of nuclear receptor coactivator 1 (NCOA1) and NCOA3 in placental development and embryo survival

Nuclear receptor coactivator 1 [NCOA1/steroid receptor coactivator (SRC)-1] and NCOA3 (SRC-3/AIB1/ACTR) constitute two thirds of the SRC (steroid receptor coactivator) family. Although in vitro experiments have suggested overlapping functions between NCOA1 and NCOA3, their in vivo functional relationship is poorly understood. In this study, NCOA1 and NCOA3 double knockout mice were generated to determine the compensatory roles of NCOA1 and NCOA3 in development. NCOA1(-/-) mice survived normally, whereas most NCOA3(-/-) embryos were viable at embryonic d 13.5 (E13.5). In contrast, the majority of double-knockout (DKO) embryos died by E13.5. NCOA1 and NCOA3 are expressed in the labyrinth, and labyrinths of NCOA1(+/-);NCOA3(-/-) and DKO placentas were small compared with wild-type and single-knockout labyrinths. DKO labyrinths exhibited low densities of maternal blood sinuses and fetal capillaries and displayed fetomaternal blood transfusion. At the interface between maternal and fetal circulations, layer I sinusoidal trophoblast giant cells showed a reduced density of microvilli. Layer III syncytiotrophoblasts appeared to accumulate large lipid droplets and have reduced density and deepened invaginations of the intrasyncytial bays. The endothelial layer in DKO labyrinth showed abnormal morphologies and had large lipid droplets. Furthermore, disruption of NCOA1 and NCOA3 increased labyrinth trophoblast proliferation and their progenitor gene expression but decreased their differentiation gene expression. NCOA1 and NCOA3 deficiencies also affected the expression of several genes for placental morphogenesis including TGFβ-, peroxisome proliferator-activated receptor-β-, and peroxisome proliferator-activated receptor-γ-regulated genes and for glucose transportation including GLUT1 and Cx26. These findings demonstrate that NCOA1 and NCOA3 cooperatively regulate placental morphogenesis and embryo survival.

Hypoxia, hormones, and endothelial progenitor cells in hemangioma

Hemangiomas are the most common tumor of infancy, and although the natural history of these lesions is well described, their etiology remains unknown. One current theory attributes the development of hemangiomas to placentally-derived cells; however, conclusive evidence to support a placental origin is lacking. While placental tissue and hemangiomas do share molecular similarities, it is possible that these parallels are the result of analogous responses of endothelial cells and vascular progenitors to similar environmental cues. Specifically, both tissue types consist of actively proliferating cells that exist within a low oxygen, high estrogen environment. The hypoxic environment leads to an upregulation of hypoxia inducible factor-1alpha (HIF-1alpha) responsive chemokines such as stromal cell derived factor-1alpha (SDF-1alpha) and vascular endothelial growth factor (VEGF), both of which are known to promote the recruitment and proliferation of endothelial progenitor cells. Increased hormone levels in the postpartum period further potentiate the growth of these lesions. In this model, increased stabilization of HIF-1 in concert with increased levels of estrogen create a milieu that promotes new blood vessel development, ultimately contributing to the pathogenesis of infantile hemangiomas.

The pathogenesis of hemangiomas: a review

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Differentiate between hemangiomas and vascular malformations. 2. Describe arguments for the trophoblast origin of hemangiomas. 3. Give arguments for the angioblast theory for the origin of hemangiomas. 4. Identify key genes involved in the origin of hemangiomas.

BACKGROUND

Hemangiomas of infancy are common endothelial tumors. They differ from vascular malformations in their tissue architecture and biological properties. To date, there is no universally accepted theory that explains the pathogenesis and pathophysiology of hemangiomas.

METHODS

Theories from the medical literature from 1981 to 2004 were gathered, categorized, and reviewed.

RESULTS

Current research is mostly on the cellular and genetic levels. The most authoritative theories focus on angioblast origins, trophoblast origins, mutations in cytokine regulatory pathways, and field defects as the cause of the deranged angiogenesis of hemangiomas.

CONCLUSIONS

To date, no single theory can easily explain all the characteristics of hemangiomas, such as predilection for the female sex, usual occurrence after birth, spontaneous involution, abnormal tissue architecture, and distribution within a developmental field. Hemangiomas are probably the final common expression of several pathophysiological mechanisms taking effect alone or in combination.

Long-term follow-up of infants after transcervical chorionic villus sampling and after amniocentesis to compare congenital abnormalities and health status

OBJECTIVES

Next to procedure-related fetal loss, other adverse effects of invasive prenatal diagnosis have been reported: limb defects after chorionic villus sampling (CVS) or early amniocentesis and respiratory distress after amniocentesis (AC). Because minor abnormalities may be overlooked in routine follow-up, we obtained long-term follow-up data after CVS and AC.

METHODS

1509 women with a singleton pregnancy who had transcervical CVS were matched by age and season of conception with 1509 women with singleton pregnancies who had AC. All procedures were performed during 1985-1991 for advanced maternal age >35 years. Data regarding congenital malformations (classified according Eurocat), neonatal and paediatric morbidity and complications of motor development, speech, hearing and visual function were obtained by questionnaire in 1993-1995.

RESULTS

Short-term outcome was known in all but ten infants. Questionnaires with a structured design were mailed to all women with a surviving infant (n=2810); 86.7% responded. No difference was detected between infants after CVS compared with infants after AC regarding congenital malformations (7.2% versus 6.3%), neonatal morbidity (15.1% versus 15.9%), paediatric morbidity with clinical treatment (7.7% versus 6.3%) or outpatient treatment only (43.9% versus 40.3%) and evident function disturbance (2.0% versus 2.0%) or doubtful function disturbance (6.3% versus 6.8%). The number of infants with physical growth <10th centile for Dutch infants was equal (10.1%). Sub-analysis for limb abnormalities or respiratory complications did not demonstrate differences between infants after CVS and AC. Only 10% of all congenital malformations were already known through routine post-partum follow-up.

CONCLUSIONS

An extensive long-term survey could not demonstrate differences of health status between infants after prenatal diagnosis by transcervical CVS and AC.

The diagnostic performance of cytogenetic investigation in amniotic fluid cells and chorionic villi

First-trimester chorionic villus sampling has not reached the popularity of second-trimester amniocentesis in prenatal cytogenetic diagnosis, in contrast to initial expectations. We investigated whether a difference in the diagnostic performances of cytogenetic investigation in amniotic fluid (AF) cells and chorionic villi in favour of AF-cells might justify this. Diagnostic performance was measured as laboratory failure rate, karyotype quality (G-band score, rate of follow-up samples, rate of wrong diagnoses), and karyotype representativity (rate of follow-up samples, rate of wrong diagnoses). From 1993-1999, 11 883 AF-samples were investigated (AF-cells). In chorionic villi, short term culture preparations solely were karyotyped from 1993-1996 (n=3499) (STC-villi), short and long-term culture preparations simultaneously provided a sufficient amount of tissue being available from 1997 onwards (n=1829) ((STC+LTC)-villi). Laboratory failure rates were the same after amniocentesis (0.40%) and chorionic villus sampling (0.50%). G-band scores (mean+/-SD) were equal in AF-cells (373+/-38.1) and LTC-villi (364+/-32.6) but significantly lower in STC-villi (311+/-34.6) (p=0.001). Follow-up sampling rates because of quality reasons were the same in AF-cells (0.14%), STC- villi (0.13%) and (STC+LTC)-villi (0.11%). Two wrong diagnoses turned up among AF-cells. Follow-up sampling rates because of representativity reasons differed significantly between AF-cells (0.10%), (STC+LTC)-villi (1.31%), and STC-villi (1.99%) (p<0.001). However, the ratios of the total numbers of follow-up samples and uncertain or abnormal cytogenetic results in STC, and (STC+LTC)-villi at cytogenetic risks > or =3% (0.132 and 0.160, respectively) were equal to that in AF-cells at risks <3% (0.155). Two wrong diagnoses were made in STC-villi. Diagnostic performance improved in the rank order of STC-villi, (STC+LTC)-villi and AF-cells. At cytogenetic risks > or =3%, (STC+LTC)-villi showed a diagnostic performance equal to that in AF-cells. This might justify a selective use of chorionic villus sampling.

Improved specificity of NRBC detection in chorionic villus sample supernatant fluids using anti-zeta and anti-epsilon monoclonal antibodies

OBJECTIVE

Fetal erythrocytes leak from fetal capillaries at the time of chorionic villus sampling (CVS). It has been reported that in approximately 60% of CVS cases fetal nucleated red blood cells (NRBC) can be isolated from the supernatant fluid by immunophenotyping with monoclonal antibody (Ab) against the gamma-chain of fetal hemoglobin and used as an additional source for confirmation of the fetal karyotype. However, the increased prevalence of beta-thalassemia mutations in countries such as Greece results in many pregnant women who produce gamma-positive cells. This makes it difficult to distinguish between the fetal and maternal origin of the NRBC. Use of Abs against embryonic hemoglobin chains zeta and epsilon may increase specificity for fetal NRBC detection.

METHODS

Mouse monoclonal Abs against Hb-zeta and Hb-epsilon were used in order to examine if specificity for fetal NRBC detection in CVS supernatant fluids could be improved. 41 samples were studied using anti-zeta and 20 using anti-epsilon monoclonal Abs.

RESULTS

Anti-zeta or anti-epsilon positive erythrocytes were, respectively, identified in 52 of 61 CVS samples and anti-zeta or anti-epsilon positive NRBC were present in all cases. The mean number of Hb-positive erythrocytes identified with the anti-zeta Ab was 58 and the mean number of NRBC 29. The mean number of anti-epsilon positive erythrocytes was 30 and of NRBC 23. FISH with X and Y chromosome specific probes was performed in 26 cases and the results were concordant with the CVS karyotype. Statistical analysis using the correlation test showed that anti-zeta and anti-epsilon were more specific for the detection of embryonic NRBCs.

CONCLUSIONS

Since embryonic monoclonal Abs show increased specificity, they should be preferentially used for NRBC detection in CVS supernatant fluids. Furthermore, the increased specificity of anti-zeta and anti-epsilon Abs may considerably improve prenatal diagnosis from fetal cells isolated from maternal circulation.

Abnormal karyotypes in semi-direct chorionic villus preparations of women with different cytogenetic risks

Among 3499 cytogenetically investigated semi-direct chorionic villus samples, 219 (6.3 per cent) abnormal karyotypes were encountered. The karyotypes were considered certainly abnormal (generalized abnormal with high probability) in 109 cases (3.1 per cent), and in 110 cases (3.1 per cent) uncertainly abnormal (potentially confined to the placenta), requiring further investigation. Of these 110 uncertain abnormalities, the cytogenetic result turned out to be finally abnormal representing generalized abnormality in 36 cases (32.7 per cent), finally normal representing confined placental mosaicism (CPM) in 69 cases (62.7 per cent), and remained undetermined in 5 instances (4.5 per cent). The rate of the numbers of certainly abnormal and all (certainly + uncertainly) abnormal results, the certainty rate, and that of generalized abnormalities and all abnormalities (generalized abnormalities + CPM cases), the predictive value, are strongly correlated with the cytogenetic risk. Therefore, we advise chorionic villus sampling for cytogenetic investigation only in women with a cytogenetic risk equal to or exceeding that of a 40-year-old pregnant woman. Because of the high rate of prenatal follow-up investigations after the finding of uncertain results in semi-direct villi, semi-direct and cultured villi should be karyotyped simultaneously.

Fetal nucleated erythrocytes (NRBCs) in chorionic villus sample supernatant fluids: an additional source of fetal material for karyotype confirmation

Fetal erythrocytes leak from the fetal capillaries at the time of chorionic villus removal. The purpose of this study was to determine if fetal nucleated erythrocytes (NRBCs) could be isolated from the chorionic villus sampling (CVS) supernatant fluid and used as an additional source of fetal material in order to confirm the fetal karyotype in cases of CVS mosaicism. One hundred CVS supernatant fluids were studied by simultaneous immunophenotyping, using a mouse antifetal haemoglobin antibody, UCH gamma, combined with fluorescent in situ hybridization (FISH) analysis using X- and Y-specific DNA probes. A chromosome 18 probe was also used in the case of a known male fetus with trisomy 18. Fetal haemoglobin (HbF)-positive cells were identified in 73 supernatant fluids and HbF-positive nucleated cells were present in 60 samples. The number of cells detected per sample showed great variation among the individual samples. FISH analysis was performed in 41 cases. FISH prediction of the fetal gender was concordant with the CVS karyotype in all cases, and the fetal trisomy 18 was correctly verified. In five cases in which Y sequences were detected, a small number of HbF-positive cells with two X signals were also identified; interestingly, in three of the five cases, the mother was a beta-thalassaemia carrier. This technique can be used as a quick and accurate method for the immediate verification of CVS results in cases of mosaicism, thus avoiding second-trimester amniocentesis.