Shalem Leemaqz

Hypoxia induced HIF-1/HIF-2 activity alters trophoblast transcriptional regulation and promotes invasion.

Reduced or absent cytotrophoblast invasion of the maternal uterine spiral arterioles is a common clinical finding in studies of pregnancies complicated by preeclampsia, suggesting that the mechanisms mediating invasion of these cells is perturbed. The placenta initially develops in a low oxygen environment of 1-2% oxygen until after the 10th week of pregnancy. During this time oxygen concentration exerts a major influence over trophoblast activity and, hypoxia inducible factors are proposed to be one of many key regulators of first trimester trophoblast behaviour. We used a global gene expression microarray approach to identify signalling pathways and hypoxia-responsive genes of interest involved in invasion of the first trimester trophoblast cell line HTR8/SVneo under hypoxic conditions where HIF-1 was active. Additionally, first trimester placental samples from different gestational age groups were labelled with anti HIF-1α and HIF-2α to evaluate whether HIFs are differentially expressed and localised across two periods of placental development: (1) early first trimester characterised by hypoxia (6-8 weeks) and (2) late first trimester after initiation of maternal blood flow into the placenta (10-12 weeks). Invasion of HTR8/SVneo was assessed in real-time and was significantly increased in 1% compared with 5% and 21% oxygen and did not differ between 5% and 21% oxygen treatments. Eighty-eight genes were differentially expressed between cells cultured in 1% oxygen (where HIF-1α protein was localised to the nucleus) and 5% oxygen (where HIF-1α was mainly cytoplasmic). 65% of the genes were predicted to contain HIF-1α:HIF-1β transcription factor binding sites. While HIF-2α staining intensity in trophoblasts of late first trimester placenta was higher than early first trimester (+57%) the percentage of positively stained trophoblast nuclei did not differ between the two time points. There was no difference in the expression level of any of the hypoxia responsive genes of interest, IGFBP3, P4HA1, P4HA2, ANGPTL4 and MMP1 between early and late first trimester placenta. While HIF-1α and its downstream targets are clearly induced in HTR8/SVneo during in vitro hypoxic conditions, it appears that hypoxia inducible factors and genes are not altered throughout the first 7-12 weeks of placental development, during which the onset of maternal blood flow to the intervillous space takes place.

Accelerated placental aging in early onset preeclampsia pregnancies identified by DNA methylation

Aim: To determine whether dynamic DNA methylation changes in the human placenta can be used to predict gestational age. Materials & methods: Publicly available placental DNA methylation data from 12 studies, together with our own dataset, using Illumina Infinium Human Methylation BeadChip arrays. Results & conclusion: We developed an accurate tool for predicting gestational age of placentas using 62 CpG sites. There was a higher predicted gestational age for placentas from early onset preeclampsia cases, but not term preeclampsia, compared with their chronological age. Therefore, early onset preeclampsia is associated with placental aging. Gestational age acceleration prediction from DNA methylation array data may provide insight into the molecular mechanisms of pregnancy disorders.

Vitamin D Receptor Gene Ablation in the Conceptus Has Limited Effects on Placental Morphology, Function and Pregnancy Outcome

Vitamin D deficiency has been implicated in the pathogenesis of several pregnancy complications attributed to impaired or abnormal placental function, but there are few clues indicating the mechanistic role of vitamin D in their pathogenesis. To further understand the role of vitamin D receptor (VDR)-mediated activity in placental function, we used heterozygous Vdr ablated C57Bl6 mice to assess fetal growth, morphological parameters and global gene expression in Vdr null placentae. Twelve Vdr +/- dams were mated at 10–12 weeks of age with Vdr +/- males. At day 18.5 of the 19.5 day gestation in our colony, females were euthanised and placental and fetal samples were collected, weighed and subsequently genotyped as either Vdr +/+, Vdr +/- or Vdr -/-. Morphological assessment of placentae using immunohistochemistry was performed and RNA was extracted and subject to microarray analysis. This revealed 25 genes that were significantly differentially expressed between Vdr +/+ and Vdr -/- placentae. The greatest difference was a 6.47-fold change in expression of Cyp24a1 which was significantly lower in the Vdr -/- placentae (P<0.01). Other differentially expressed genes in Vdr -/- placentae included those involved in RNA modification (Snord123), autophagy (Atg4b), cytoskeletal modification (Shroom4), cell signalling (Plscr1, Pex5) and mammalian target of rapamycin (mTOR) signalling (Deptor and Prr5). Interrogation of the upstream sequence of differentially expressed genes identified that many contain putative vitamin D receptor elements (VDREs). Despite the gene expression differences, this did not contribute to any differences in overall placental morphology, nor was function affected as there was no difference in fetal growth as determined by fetal weight near term. Given our dams still expressed a functional VDR gene, our results suggest that cross-talk between the maternal decidua and the placenta, as well as maternal vitamin D status, may be more important in determining pregnancy outcome than conceptus expression of VDR.

The INSR rs2059806 single nucleotide polymorphism, a genetic risk factor for vascular and metabolic disease, associates with pre-eclampsia

Pre-eclampsia is a risk factor for later life vascular and metabolic diseases. This study postulates that this reflects a common genetic cause, and investigates whether the INSR rs2059806 single nucleotide polymorphism (SNP) (a risk factor for essential hypertension, type 2 diabetes and metabolic syndrome) is also associated with pre-eclampsia. The association of INSR rs2059806 with pre-eclampsia was tested in two cohorts - a Caucasian case control group (123 pre-eclamptic mother-father-baby trios and 1185 mother-father-baby trios from uncomplicated pregnancies) and an independent cohort of Sinhalese women (175 women with pre-eclampsia and 171 women with uncomplicated pregnancies). In the Caucasian cohort, the prevalence of the INSR rs2059806 AA genotype was greater among pre-eclamptic women compared with the uncomplicated pregnancies (12.7% versus 4.7%, OR[95%CI] = 3.1[1.6-5.8], P = 0.0003). In the Sinhalese cohort, maternal INSR rs2059806 AA genotype was greater among pre-eclamptic women who delivered small for gestational age infants compared with the uncomplicated pregnancies (10.8% versus 4.2%, OR[95%CI] = 2.8[1.0-7.4], P = 0.03). Thus, it was found that the INSR rs2059806 SNP is also associated with pre-eclampsia phenotypes in two independent cohorts suggesting that genetic susceptibility may be implicated in the link between pre-eclampsia and subsequent vascular and metabolic diseases.

The obesity associated FTO gene variant and the risk of adverse pregnancy outcomes: Evidence from the SCOPE study

To investigate whether the FTO rs9939609 single nucleotide polymorphism (SNP), which is a risk factor for obesity and vascular diseases, is also associated with pregnancy complications including pre‐eclampsia, gestational hypertension, small for gestational age pregnancy (SGA), and spontaneous preterm birth (sPTB).

Causes of stillbirth in a socioeconomically disadvantaged urban Australian population – a comprehensive analysis

Abstract Introduction: The aim of this paper was to provide an in-depth analysis of all stillbirth causation over a period of 10 years in a busy maternity unit located in a socioeconomically disadvantaged urban area, with an emphasis on overlapping pathology. Materials and methods: A retrospective analysis of all structurally normal stillbirths in singleton pregnancies born during 2002–2012. The PSANZ stillbirth classification was used; per stillbirth subgroup main risk factors were evaluated. Results: Out of 130 cases, 43% showed overlapping pathologies. In the remaining 74 (56%) cases, the following single pathologies were found: IUGR 20 (15%), infection 12 (9%), abruption 8 (6%), placental thrombotic pathology 8 (6%), miscellaneous 6 stillbirths (5%), and 20 cases (15%) unexplained. Smoking was a risk factor for stillbirth associated with abruption (OR 3.639), infection (OR 2.271), and thrombotic pathology (OR 2.168). Drug use had an association with (placental) infection (OR 3.598). Obesity showed a significant association with IUGR (OR 3.782) and abruption (OR 9.040). Thrombophilia risk analysis for the overall group of stillbirths showed significant results for Protein S (OR 8.889) and homocysteine >90th centile (OR 2.087). Conclusions: Overlapping pathology was identified in 43% of stillbirths. Infection, IUGR, and abruption were the most important single cause of stillbirth.

Risk factors for stillbirth in a socio-economically disadvantaged urban Australian population

Abstract Introduction: Several risk factors for stillbirth have been extensively investigated. Some risk factors are more common in socio-economically disadvantaged regions. The aim of this study was to identify risk factors for stillbirth in the Northern suburbs of Adelaide, one of the most socio-economically disadvantaged urban areas in Australia. Material and methods: A retrospective case control study (two controls per case) of all women with a singleton pregnancy resulting in a stillbirth during the decade 2002–2012. Results: One hundred and thirty stillbirths were registered over these 10 years. Using univariate analysis, the following risk factors were identified: obesity ≥40 body mass index (BMI) (OR 4.75), non-Caucasian ethnicity (odds ratio [OR] 2.737), pre-existing diabetes (p <0.000), polycystic ovary syndrome (PCOS) (OR 5.250), in vitro fertilisation (IVF) (OR 4.000), booking systolic blood pressure (SBP) ≥ 140 (OR 5.000) and booking diastolic blood pressure (DBP) ≥ 80 (OR 3.111). Many of these factors have complex interrelationships. Multivariate analysis identified the following independent risk factors: BMI ≥40 (OR 3.940), ethnic minorities (mainly indigenous Australians) (OR 2.255) and social issues (OR 3.079). PCOS had an independent effect to some extent, but this was clearly confounded by BMI. Conclusion: These Australian data confirm the presence of several potentially modifiable risk factors for stillbirth, within this socio-economically disadvantaged region. Modifying these risk factors, in particular obesity, is a big challenge not only for maternity and primary care providers, but for overall society.

Insulin family polymorphisms in pregnancies complicated by small for gestational age infants

Being born small for gestational age (SGA) increases the risk for adverse perinatal outcomes and later life vascular and metabolic disorders. The insulin family plays a vital role in intrauterine growth. We investigated the association of functional SNPs in insulin (INS), insulin receptor (INSR) and insulin receptor substrate 2 (IRS2) with small for gestational age (SGA) pregnancies, uterine and umbilical artery Doppler and plasma insulin level. We conducted a nested case-control study of 1401 nulliparous Caucasian women, their partners and babies (216 SGA and 1185 uncomplicated). SGA was defined as a birthweight less than the 10th customized birthweight percentile adjusted for maternal height, weight, parity, ethnicity, gestational age at delivery and infant sex. Uterine and umbilical artery Doppler was performed at 20 ± 1 week gestation. The SNPs in the parent infant trios were genotyped using Sequenom MassARRAY. Plasma insulin was measured by double antibody RIA in 188 healthy non-pregnant adults to assess correlations between SNP genotypes and circulating insulin. Paternal [odds ratio (OR) (95% CI) = 2.2 (1.3-3.9), P = 0.005] and infant [OR (95% CI) = 3.3 (1.7-6.2), P = 0.0001] INSR rs2059806 AA genotype was associated with SGA. Infant INSR rs2059806 A allele was associated with abnormal umbilical artery Doppler [OR (95% CI) = 1.3(1.0-1.7), P = 0.04]. INSR rs2059806 AA homozygous individuals had lower plasma insulin compared with heterozygotes (P = 0.03) and GG homozygotes (P = 0.03). The INSR rs2059806 SNP previously associated with adult vascular and metabolic diseases is also associated with SGA pregnancies. This polymorphism may associate with the risk of vascular and metabolic disorders across the life course.

MsgbsR: An R package for analysing methylation-sensitive restriction enzyme sequencing data

Genotyping-by-sequencing (GBS) or restriction-site associated DNA marker sequencing (RAD-seq) is a practical and cost-effective method for analysing large genomes from high diversity species. This method of sequencing, coupled with methylation-sensitive enzymes (often referred to as methylation-sensitive restriction enzyme sequencing or MRE-seq), is an effective tool to study DNA methylation in parts of the genome that are inaccessible in other sequencing techniques or are not annotated in microarray technologies. Current software tools do not fulfil all methylation-sensitive restriction sequencing assays for determining differences in DNA methylation between samples. To fill this computational need, we present msgbsR, an R package that contains tools for the analysis of methylation-sensitive restriction enzyme sequencing experiments. msgbsR can be used to identify and quantify read counts at methylated sites directly from alignment files (BAM files) and enables verification of restriction enzyme cut sites with the correct recognition sequence of the individual enzyme. In addition, msgbsR assesses DNA methylation based on read coverage, similar to RNA sequencing experiments, rather than methylation proportion and is a useful tool in analysing differential methylation on large populations. The package is fully documented and available freely online as a Bioconductor package (https://bioconductor.org/packages/release/bioc/html/msgbsR.html).

Asthma treatment impacts time to pregnancy: evidence from the international SCOPE study

Asthma is a common chronic disease affecting the lives of reproductive age women and is associated with 8–13% of pregnancies [1]. While maternal asthma has been consistently associated with significant perinatal morbidities and mortality [2, 3], impacts on fertility are conflicting. In light of limited and conflicting evidence, the aim of this study was to examine the impact of asthma and asthma medication use on fecundability and time to pregnancy. Use of short-acting relievers but not long-term preventers is associated with reduced fertility in asthmatic women http://ow.ly/fMAk30homkB