Profiling placental and fetal DNA methylation in human neural tube defects.

Background: The incidence of neural tube defects (NTDs) declined by about 40 % in Canada with the introduction of a national folic acid (FA) fortification program. Despite the fact that few Canadians currently exhibit folate deficiency, NTDs are still the second most common congenital abnormality. FA fortification may have aided in reducing the incidence of NTDs by overcoming abnormal one carbon metabolism cycling, the process which provides one carbon units for methylation of DNA.

Pervasive polymorphic imprinted methylation in the human placenta.

The maternal and paternal copies of the genome are both required for mammalian development, and this is primarily due to imprinted genes, those that are monoallelically expressed based on parent-of-origin. Typically, this pattern of expression is regulated by differentially methylated regions (DMRs) that are established in the germline and maintained after fertilization. There are a large number of germline DMRs that have not yet been associated with imprinting, and their function in development is unknown.

Chorioamnionitis in the pathogenesis of brain injury in preterm infants.

Chorioamnionitis (or placental infection) is suspected to be a risk factor for brain injury in premature infants. The suggested association between chorioamnionitis and cystic periventricular leukomalacia and cerebral palsy is uncertain because of the variability of study designs and definitions of chorioamnionitis. Improvements in neonatal intensive care may have attenuated the impact of chorioamnionitis on brain health outcomes.

Widespread DNA hypomethylation at gene enhancer regions in placentas associated with early-onset pre-eclampsia.

Pre-eclampsia is a serious complication of pregnancy that can affect both maternal and fetal outcomes. Early-onset pre-eclampsia (EOPET) is a severe form of pre-eclampsia that is associated with altered physiological characteristics and gene expression in the placenta. DNA methylation is a relatively stable epigenetic modification to DNA that can reflect gene expression, and can provide insight into the mechanisms underlying such expression changes.

Early onset pre-eclampsia is associated with altered DNA methylation of cortisol-signalling and steroidogenic genes in the placenta.

Placental cortisol is inactivated in normotensive pregnancies, but is frequently present in pre-eclampsia associated placentae. Since glucocorticoids are strongly associated with the programming of long-term health, we assessed DNA methylation of genes involved in cortisol signalling and bioavailability, and hormonal signalling in the placenta of normotensive and hypertensive pregnancies. Candidate genes/CpG sites were selected through analysis of Illumina Infinium HumanMethylation450 BeadChip array data on control (n = 19) and early onset pre-eclampsia (EOPET; n = 19) placental samples.

DNA methylation profiling of placental villi from karyotypically normal miscarriage and recurrent miscarriage.

Miscarriage occurs in 15% of clinical pregnancies. Although chromosomal errors are observed in >50%, causes of karyotypically normal losses are poorly understood. DNA methylation undergoes reprogramming during development and must be appropriately set to maintain a healthy pregnancy.

Protein kinase profiling in miscarriage: implications for the pathogenesis of trisomic pregnancy.

Objective: Trisomy in pregnancy increases risks of miscarriage, fetal anomalies, and perinatal complications, with trisomy 16 the most common trisomy in human conceptions. The pathogenesis and protein expression profiles in trisomic pregnancy have not been well elucidated. Our objective was to profile protein kinase expression in trisomic and chromosomally normal miscarriage.

Different measures of "genome-wide" DNA methylation exhibit unique properties in placental and somatic tissues.

DNA methylation of CpGs located in two types of repetitive elements-LINE1 (L1) and Alu-is used to assess "global" changes in DNA methylation in studies of human disease and environmental exposure. L1 and Alu contribute close to 30% of all base pairs in the human genome and transposition of repetitive elements is repressed through DNA methylation. Few studies have investigated whether repetitive element DNA methylation is associated with DNA methylation at other genomic regions, or the biological and technical factors that influence potential associations.

Early inflammation in the absence of overt infection in preterm neonates exposed to intensive care.

Background: Systemic inflammation, typically attributed to sepsis, has been repeatedly linked to adverse long-term outcomes in infants born prematurely. However, it is unclear whether other factors can contribute to potentially harmful systemic inflammatory responses.

Objective: To determine the timing and extent of systemic inflammation occurring in absence of infection in preterm infants exposed to intensive care.

Genome-wide mapping of imprinted differentially methylated regions by DNA methylation profiling of human placentas from triploidies.

Background: Genomic imprinting is an important epigenetic process involved in regulating placental and foetal growth. Imprinted genes are typically associated with differentially methylated regions (DMRs) whereby one of the two alleles is DNA methylated depending on the parent of origin. Identifying imprinted DMRs in humans is complicated by species- and tissue-specific differences in imprinting status and the presence of multiple regulatory regions associated with a particular gene, only some of which may be imprinted.

Developmental origin of chorionic villus cultures from spontaneous abortion and chorionic villus sampling.

Objective: Chorionic villus cultures from spontaneous abortions and chorionic villus sampling (CVS) are routinely used for clinical cytogenetic analysis. Although these cultures are assumed to represent the chorionic villus mesenchymal core, and therefore the inner cell mass (ICM) of the blastocyst, immunochemical studies using a true trophoblast-specific marker to definitively rule out trophoblast contamination have not been done. Therefore, we used cytokeratin-7 (CK7), a trophoblast-specific marker, to assess the developmental origin of these chorionic villus cultures.

Chromosome-wide DNA methylation analysis predicts human tissue-specific X inactivation.

X-chromosome inactivation (XCI) results in the differential marking of the active and inactive X with epigenetic modifications including DNA methylation. Consistent with the previous studies showing that CpG island-containing promoters of genes subject to XCI are approximately 50% methylated in females and unmethylated in males while genes which escape XCI are unmethylated in both sexes; our chromosome-wide (Methylated DNA ImmunoPrecipitation) and promoter-targeted methylation analyses (Illumina Infinium HumanMethylation27 array) showed the largest methylation difference (D = 0.12, p < 2.

Extensive epigenetic reprogramming in human somatic tissues between fetus and adult.

Background: Development of human tissue is influenced by a combination of intrinsic biological signals and extrinsic environmental stimuli, both of which are mediated by epigenetic regulation, including DNA methylation. However, little is currently known of the normal acquisition or loss of epigenetic markers during fetal and postnatal development.

Results: The DNA methylation status of over 1000 CpGs located in the regulatory regions of nearly 800 genes was evaluated in five somatic tissues (brain, kidney, lung, muscle and skin) from eight normal second-trimester fetuses.

DNA methylation profiling of human placentas reveals promoter hypomethylation of multiple genes in early-onset preeclampsia.

Preeclampsia and intrauterine growth restriction (IUGR) are two of the most common adverse pregnancy outcomes, but their underlying causes are mostly unknown. Although multiple studies have investigated gene expression changes in these disorders, few studies have examined epigenetic changes. Analysis of the DNA methylation pattern associated with such pregnancies provides an alternative approach to identifying cellular changes involved in these disorders.

Assessing the role of placental trisomy in preeclampsia and intrauterine growth restriction.

Objective: Prenatally diagnosed confined placental trisomy is associated with increased risk for intrauterine growth restriction (IUGR) and preeclampsia. However, it is unclear how often this might underlie pregnancy complications. Our objective was to evaluate the frequency and distribution of trisomic cells in placentae ascertained for IUGR and/or preeclampsia.

Placental weight in pregnancies with trisomy confined to the placenta.

Objective: Mosaicism with trisomy confined to the placenta is present in ~1% of ongoing pregnancies at the time of chorionic villus sampling. Some studies have found reduced fetal growth in confined placental trisomy. The objective of this study was to assess placental weight and feto-placental weight ratio in pregnancies with trisomy confined to the placenta, and to correlate them with the level of trisomy in the three major placental lineages.

Effect of chorioamnionitis on brain development and injury in premature newborns.

Objective: The association of chorioamnionitis and noncystic white matter injury, a common brain injury in premature newborns, remains controversial. Our objectives were to determine the association of chorioamnionitis and postnatal risk factors with white matter injury, and the effects of chorioamnionitis on early brain development, using advanced magnetic resonance imaging.

Methods: Ninety-two preterm newborns (24-32 weeks gestation) were studied at a median age of 31.

Origin and outcome of pregnancies affected by androgenetic/biparental chimerism.

Background: Androgenetic diploid cells confined to the placenta have recently been reported in several cases of normally developed fetuses in association with placental mesenchymal dysplasia (PMD).

Methods And Results: We investigated two singleton, mildly growth-restricted, female pregnancies ascertained on the basis of PMD. One case had liver hemangiomas and both infants had multiple skin hemangiomas.

Immunolocalization of estrogen receptor alpha and beta in human fetal prostate.

Purpose: We examined the immunolocalization of estrogen receptor (ER)alpha and ERbeta in the human fetal prostate.

Materials And Methods: Tissue sections from human fetal prostates at 7 to 22 weeks of gestation were stained with antibodies to ERalpha, ERbeta, and cytokeratin 10 and 14.

Results: ERalpha expression was not detected until 15 weeks of gestation with sparse staining in the utricle.

Immunolocalization of androgen receptor and estrogen receptors alpha and beta in human fetal testis and epididymis.

Purpose: Expression and cellular localization of the androgen receptor (AR) and estrogen receptor (ER) isoforms were determined using antibodies specific to these receptors and to specific cell types.

Materials And Methods: Gonads and genitourinary structures were removed from 5 human male fetuses 7 to 22 weeks of gestational age. Sections were stained with antibodies to AR, ERalpha and ERbeta, P450 scc and smooth muscle actin.

The prostatic utricle is not a Müllerian duct remnant: immunohistochemical evidence for a distinct urogenital sinus origin.

Purpose: The embryological origin of the utricle is thought to be a remnant of the fused caudal ends of the müllerian ducts (MDs). Others propose that the urogenital sinus (UGS) contributes either partially or totally to the development of this structure. Using immunohistochemical probes, we provide strong evidence that the utricle is of UGS origin only.

Dispermy--origin of diandric triploidy: brief communication.

Triploidy may arise from either digynic or diandric fertilizations. Errors in the second meiotic division account for most digynic triploidy while most studies have found that approximately 2/3 of diandric triploids arise as the result of dispermy and 1/3 as the result of meiotic errors giving rise to diploid sperm. Using molecular markers very close to the centromere, all 14 cases of diandric triploidy were shown to be the result of dispermy with no evidence to support a meiotic error as the origin of diandric triploids.