General Practitioners perspectives on infant telomere length screening after a pregnancy complication: a qualitative analysis.

BACKGROUND: Pregnancy complications can impact the mother and child's health in the short and longterm resulting in an increased risk of chronic disease later in life. Telomere length is a biomarker of future cardiometabolic diseases and may offer a novel way of identifying offspring most at risk for future chronic diseases. OBJECTIVE(S): To qualitatively explore General Practitioners' (GPs) perspectives on the feasibility and uptake for recommending a telomere screening test in children who were born after a pregnancy complication. METHODS: Twelve semi-structured interviews were conducted with GPs within metropolitan Adelaide, South Australia. Interviews were audio recorded, transcribed verbatim, and analysed for codes and themes. RESULTS: Two themes were generated: ethical considerations and practical considerations. Ethically, the GP participants discussed barriers including consenting on behalf of a child, parental guilt, and the impact of health insurance, whereas viewing it for health promotion was a facilitator. For practical considerations, barriers included the difficulty in identifying people eligible for screening, maintaining medical communication between service providers, and time and financial constraints, whereas linking screening for telomere length with existing screening would facilitate uptake. CONCLUSIONS: GPs were generally supportive of potential telomere screening in infants, particularly via a saliva test that could be embedded in current antenatal care. However, several challenges, such as lack of knowledge, ethical considerations, and time and financial constraints, need to be overcome before such a test could be implemented into practice.

Around one fifth of women experience a pregnancy complication that places their infants at higher risk for a range of chronic diseases in later life. Although not all infants will have adverse health outcomes, it is important to identify offspring early in life who may be at higher risk. Telomere length is a biomarker of future chronic disease that can be obtained from blood or saliva. Whether telomere length might be useful as a screening tool in newborns born from a pregnancy complication has not been investigated. This study qualitatively explores the perspectives of 12 general practitioners in Adelaide, Australia, on the feasibility and uptake of telomere screening in children born after a pregnancy complication. Overall, general practitioners were generally supportive of potential telomere screening in infants, particularly via a saliva test that could be embedded in current antenatal care. However, several challenges, such as lack of knowledge, ethical considerations, and time and financial constraints, need to be overcome before such a test could be implemented into practice. Study findings contribute to the limited knowledge assessing follow-up of screening after pregnancy within Australia and internationally and provide novel findings on a potential new screening tool that could be considered early in life.

The role of angiotensin II and relaxin in vascular adaptation to pregnancy.

In brief: There is a pregnancy-induced vasodilation of blood vessels, which is known to have a protective effect on cardiovascular function and can be maintained postpartum. This review outlines the cardiovascular changes that occur in a healthy human and rodent pregnancy, as well as different pathways that are activated by angiotensin II and relaxin that result in blood vessel dilation. Abstract: During pregnancy, systemic and uteroplacental blood flow increase to ensure an adequate blood supply that carries oxygen and nutrients from the mother to the fetus. This results in changes to the function of the maternal cardiovascular system. There is also a pregnancy-induced vasodilation of blood vessels, which is known to have a protective effect on cardiovascular health/function. Additionally, there is evidence that the effects of maternal vascular vasodilation are maintained post-partum, which may reduce the risk of developing high blood pressure in the next pregnancy and reduce cardiovascular risk later in life. At both non-pregnant and pregnant stages, vascular endothelial cells produce a number of vasodilators and vasoconstrictors, which transduce signals to the contractile vascular smooth muscle cells to control the dilation and constriction of blood vessels. These vascular cells are also targets of other vasoactive factors, including angiotensin II (Ang II) and relaxin. The binding of Ang II to its receptors activates different pathways to regulate the blood vessel vasoconstriction/vasodilation, and relaxin can interact with some of these pathways to induce vasodilation. Based on the available literature, this review outlines the cardiovascular changes that occur in a healthy human pregnancy, supplemented by studies in rodents. A specific focus is placed on vasodilation of blood vessels during pregnancy; the role of endothelial cells and endothelium-derived vasodilators will also be discussed. Additionally, different pathways that are activated by Ang II and relaxin that result in blood vessel dilation will also be reviewed.

Maternal metabolic factors and the association with gestational diabetes: A systematic review and meta-analysis.

Gestational diabetes (GDM) is associated with several adverse outcomes for the mother and child. Higher levels of individual lipids are associated with risk of GDM and metabolic syndrome (MetS), a clustering of risk factors also increases risk for GDM. Metabolic factors can be modified by diet and lifestyle. This review comprehensively evaluates the association between MetS and its components, measured in early pregnancy, and risk for GDM. Databases (Cumulative Index to Nursing and Allied Health Literature, PubMed, Embase, and Cochrane Library) were searched from inception to 5 May 2021. Eligible studies included ≥1 metabolic factor (waist circumference, blood pressure, fasting plasma glucose (FPG), triglycerides, and high-density lipoprotein cholesterol), measured at <16 weeks' gestation. At least two authors independently screened potentially eligible studies. Heterogeneity was quantified using I2 . Data were pooled by random-effects models and expressed as odds ratio and 95% confidence intervals (CIs). Of 7213 articles identified, 40 unique articles were included in meta-analysis. In analyses adjusting for maternal age and body mass index, GDM was increased with increasing FPG (odds ratios [OR] 1.92; 95% CI 1.39-2.64, k = 7 studies) or having MetS (OR 2.52; 1.65, 3.84, k = 3). Women with overweight (OR 2.17; 95% CI 1.89, 2.50, k = 12) or obesity (OR 4.34; 95% CI 2.79-6.74, k = 9) also were at increased risk for GDM. Early pregnancy assessment of glucose or the MetS, offers a potential opportunity to detect and treat individual risk factors as an approach towards GDM prevention; weight loss for pregnant women with overweight or obesity is not recommended. Systematic review registration: PROSPERO CRD42020199225.

Placental Transcription Profiling in 6-23 Weeks' Gestation Reveals Differential Transcript Usage in Early Development.

The human placenta is a rapidly developing transient organ that is key to pregnancy success. Early development of the conceptus occurs in a low oxygen environment before oxygenated maternal blood begins to flow into the placenta at ~10-12 weeks' gestation. This process is likely to substantially affect overall placental gene expression. Transcript variability underlying gene expression has yet to be profiled. In this study, accurate transcript expression profiles were identified for 84 human placental chorionic villus tissue samples collected across 6-23 weeks' gestation. Differential gene expression (DGE), differential transcript expression (DTE) and differential transcript usage (DTU) between 6-10 weeks' and 11-23 weeks' gestation groups were assessed. In total, 229 genes had significant DTE yet no significant DGE. Integration of DGE and DTE analyses found that differential expression patterns of individual transcripts were commonly masked upon aggregation to the gene-level. Of the 611 genes that exhibited DTU, 534 had no significant DGE or DTE. The four most significant DTU genes ADAM10, VMP1, GPR126, and ASAH1, were associated with hypoxia-responsive pathways. Transcript usage is a likely regulatory mechanism in early placentation. Identification of functional roles will facilitate new insight in understanding the origins of pregnancy complications.

Large-scale transcriptome-wide profiling of microRNAs in human placenta and maternal plasma at early to mid gestation.

MicroRNAs (miRNAs) are increasingly seen as important regulators of placental development and opportunistic biomarker targets. Given the difficulty in obtaining samples from early gestation and subsequent paucity of the same, investigation of the role of miRNAs in early gestation human placenta has been limited. To address this, we generated miRNA profiles using 96 placentas from presumed normal pregnancies, across early gestation, in combination with matched profiles from maternal plasma. Placenta samples range from 6 to 23 weeks' gestation, a time period that includes placenta from the early, relatively low but physiological (6-10 weeks' gestation) oxygen environment, and later, physiologically normal oxygen environment (11-23 weeks' gestation).We identified 637 miRNAs with expression in 86 samples (after removing poor quality samples), showing a clear gestational age gradient from 6 to 23 weeks' gestation. We identified 374 differentially expressed (DE) miRNAs between placentas from 6-10 weeks' versus 11-23 weeks' gestation. We see a clear gestational age group bias in miRNA clusters C19MC, C14MC, miR-17 ~ 92 and paralogs, regions that also include many DE miRNAs. Proportional change in expression of placenta-specific miRNA clusters was reflected in maternal plasma.The presumed introduction of oxygenated maternal blood into the placenta (between ~10 and 12 weeks' gestation) changes the miRNA profile of the chorionic villus, particularly in placenta-specific miRNA clusters. Data presented here comprise a clinically important reference set for studying early placenta development and may underpin the generation of minimally invasive methods for monitoring placental health.

Maternal folate, one-carbon metabolism and pregnancy outcomes.

Single nucleotide polymorphisms and pre- and peri-conception folic acid (FA) supplementation and dietary data were used to identify one-carbon metabolic factors associated with pregnancy outcomes in 3196 nulliparous women. In 325 participants, we also measured circulating folate, vitamin B12 and homocysteine. Pregnancy outcomes included preeclampsia (PE), gestational hypertension (GHT), small for gestational age (SGA), spontaneous preterm birth (sPTB) and gestational diabetes mellitus (GDM). Study findings show that maternal genotype MTHFR A1298C(CC) was associated with increased risk for PE, whereas TCN2 C766G(GG) had a reduced risk for sPTB. Paternal MTHFR A1298C(CC) and MTHFD1 G1958A(AA) genotypes were associated with reduced risk for sPTB, whereas MTHFR C677T(CT) genotype had an increased risk for GHT. FA supplementation was associated with higher serum folate and vitamin B12 concentrations, reduced uterine artery resistance index and increased birth weight. Women who supplemented with <800 µg daily FA at 15-week gestation had a higher incidence of PE (10.3%) compared with women who did not supplement (6.1%) or who supplemented with ≥800 µg (5.4%) (P < .0001). Higher serum folate levels were found in women who later developed GDM compared with women with uncomplicated pregnancies (Mean ± SD: 37.6 ± 8 nmol L-1 vs. 31.9 ± 11.2, P = .007). Fast food consumption was associated with increased risk for developing GDM, whereas low consumption of green leafy vegetables and fruit were independent risk factors for SGA and GDM and sPTB and SGA, respectively. In conclusion, maternal and paternal genotypes, together with maternal circulating folate and homocysteine concentrations, and pre- and early-pregnancy dietary factors, are independent risk factors for pregnancy complications.

The metabolic syndrome in pregnancy and its association with child telomere length.

AIMS/HYPOTHESIS: The aim of this study was to determine whether presence of the metabolic syndrome in pregnancy associates with child telomere length or child anthropometry (weight, BMI) and BP, measured at 10 years of age. METHODS: The Screening for Pregnancy Endpoints study (SCOPE) was a multicentre, international prospective cohort of nulliparous pregnant women recruited from Australia, New Zealand, Ireland and the UK (N = 5628). The current analysis is a 10 year follow-up of SCOPE pregnant women and their children, from the Australian cohort. Clinical data collected at 14-16 weeks' gestation during the SCOPE study were used to diagnose the metabolic syndrome using IDF criteria. Telomere length, a biomarker of ageing, was assessed by quantitative PCR from children's saliva collected at 10 years of age. RESULTS: In women who completed follow-up (n = 255), 20% had the metabolic syndrome in pregnancy. After adjusting for a range of confounders, children of mothers who had the metabolic syndrome in pregnancy had 14% shorter telomeres than children of mothers without the metabolic syndrome in pregnancy (mean difference -0.36 [95% CI -0.74, 0.01]). Height- and weight-for-age, and BMI z scores were similar in children of mothers who did and did not have the metabolic syndrome during pregnancy. CONCLUSIONS/INTERPRETATION: Children of mothers who had the metabolic syndrome in pregnancy have shorter telomeres, a biomarker of accelerated ageing. These findings warrant further studies in larger cohorts of children, as well as investigations into whether telomere length measured in cord blood associates with telomere length in childhood.

Elevated levels of tumour apolipoprotein D independently predict poor outcome in breast cancer patients.

AIMS: Apolipoprotein D (ApoD) is a protein that is regulated by androgen and oestrogen, and is a major constituent of breast cysts. Although ApoD has been reported to be a marker of breast cancer, its prognostic importance in invasive breast cancer is unclear. The aim of this study was to investigate the relationship between ApoD protein expression, oestrogen receptor-α (ERα) expression and androgen receptor (AR) expression in predicting breast cancer outcome. METHODS AND RESULTS: ApoD levels were measured by the use of immunohistochemistry and video image analysis on tissue sections from a breast cancer cohort (n = 214). We assessed the associations of ApoD expression with disease-free survival (DFS), metastasis-free survival (MFS), and overall survival (OS). We also assessed the relationship between ApoD expression, AR expression and ERα expression in predicting OS. ApoD expression (>1% ApoD positivity) was found in 72% (154/214) of tissues. High ApoD positivity (≥20.7%, fourth quartile) was an independent predictor of MFS and OS, and conferred a 2.2-fold increased risk of developing metastatic disease and a 2.1-fold increased risk of breast cancer-related death. ApoD positivity was not associated with AR or ERα nuclear positivity. However, patients with (≥1%) ERα-positive cancers with low (<20.7%) ApoD positivity, or those showing high (≥78%) AR positivity and low (<20.7%) ApoD positivity had better OS than other patient groups. CONCLUSIONS: ApoD expression could be used to predict breast cancer prognosis independently of ERα and AR expression.

An analysis of a multiple biomarker panel to better predict prostate cancer metastasis after radical prostatectomy.

A plethora of individual candidate biomarkers for predicting biochemical relapse in localized prostate cancer (PCa) have been proposed. Combined biomarkers may improve prognostication, and ensuring validation against more clinically relevant endpoints are required. The Australian PCa Research Centre NSW has contributed to numerous studies of molecular biomarkers associated with biochemical relapse. In the current study, these biomarkers were re-analyzed for biochemical relapse, metastatic relapse and PCa death with extended follow-up. Biomarkers of significance were then used to develop a combined prognostic model for clinical outcomes and validated in a large independent cohort. The discovery cohort (n = 324) was based on 12 biomarkers with a median follow-up of 16 years. Seven biomarkers were significantly associated with biochemical relapse. Three biomarkers were associated with metastases: AZGP1, Ki67 and PML. Only AZGP1 was associated with PCa death. In their individual and combinational forms, AZGP1 and Ki67 as a dual BM signature was the most robust predictor of metastatic relapse (AUC 0.762). The AZPG1 and Ki67 signature was validated in an independent cohort of 347 PCa patients. The dual BM signature of AZGP1 and Ki67 predicted metastasis in the univariable (HR 7.2, 95% CI, 1.6-32; p = 0.01) and multivariable analysis (HR 5.4, 95% CI, 1.2-25; p = 0.03). The dual biomarker signature marginally improved risk prediction compared to AZGP1 alone (AUC 0.758 versus 0.738, p < 0.001). Our findings indicate that biochemical relapse is not an adequate surrogate for metastasis or PCa death. The dual biomarker signature of AZGP1 and Ki67 offers a small benefit in predicting metastasis over AZGP1 alone.

Metabolic syndrome in pregnancy and risk for adverse pregnancy outcomes: A prospective cohort of nulliparous women.

BACKGROUND: Obesity increases the risk for developing gestational diabetes mellitus (GDM) and preeclampsia (PE), which both associate with increased risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) in women in later life. In the general population, metabolic syndrome (MetS) associates with T2DM and CVD. The impact of maternal MetS on pregnancy outcomes, in nulliparous pregnant women, has not been investigated. METHODS AND FINDINGS: Low-risk, nulliparous women were recruited to the multi-centre, international prospective Screening for Pregnancy Endpoints (SCOPE) cohort between 11 November 2004 and 28 February 2011. Women were assessed for a range of demographic, lifestyle, and metabolic health variables at 15 ± 1 weeks' gestation. MetS was defined according to International Diabetes Federation (IDF) criteria for adults: waist circumference ≥80 cm, along with any 2 of the following: raised trigycerides (≥1.70 mmol/l [≥150 mg/dl]), reduced high-density lipoprotein cholesterol (<1.29 mmol/l [<50 mg/dl]), raised blood pressure (BP) (i.e., systolic BP ≥130 mm Hg or diastolic BP ≥85 mm Hg), or raised plasma glucose (≥5.6 mmol/l). Log-binomial regression analyses were used to examine the risk for each pregnancy outcome (GDM, PE, large for gestational age [LGA], small for gestational age [SGA], and spontaneous preterm birth [sPTB]) with each of the 5 individual components for MetS and as a composite measure (i.e., MetS, as defined by the IDF). The relative risks, adjusted for maternal BMI, age, study centre, ethnicity, socioeconomic index, physical activity, smoking status, depression status, and fetal sex, are reported. A total of 5,530 women were included, and 12.3% (n = 684) had MetS. Women with MetS were at an increased risk for PE by a factor of 1.63 (95% CI 1.23 to 2.15) and for GDM by 3.71 (95% CI 2.42 to 5.67). In absolute terms, for PE, women with MetS had an adjusted excess risk of 2.52% (95% CI 1.51% to 4.11%) and, for GDM, had an adjusted excess risk of 8.66% (95% CI 5.38% to 13.94%). Diagnosis of MetS was not associated with increased risk for LGA, SGA, or sPTB. Increasing BMI in combination with MetS increased the estimated probability for GDM and decreased the probability of an uncomplicated pregnancy. Limitations of this study are that there are several different definitions for MetS in the adult population, and as there are none for pregnancy, we cannot be sure that the IDF criteria are the most appropriate definition for pregnancy. Furthermore, MetS was assessed in the first trimester and may not reflect pre-pregnancy metabolic health status. CONCLUSIONS: We did not compare the impact of individual metabolic components with that of MetS as a composite, and therefore cannot conclude that MetS is better at identifying women at risk. However, more than half of the women who had MetS in early pregnancy developed a pregnancy complication compared with just over a third of women who did not have MetS. Furthermore, while increasing BMI increases the probability of GDM, the addition of MetS exacerbates this probability. Further studies are required to determine if individual MetS components act synergistically or independently.

Pre-pregnancy fast food and fruit intake is associated with time to pregnancy.

STUDY QUESTION: Is preconception dietary intake associated with reduced fecundity as measured by a longer time to pregnancy (TTP)? SUMMARY ANSWER: Lower intake of fruit and higher intake of fast food in the preconception period were both associated with a longer TTP. WHAT IS KNOWN ALREADY: Several lifestyle factors, such as smoking and obesity, have consistently been associated with a longer TTP or infertility, but the role of preconception diet in women remains poorly studied. Healthier foods or dietary patterns have been associated with improved fertility, however, these studies focused on women already diagnosed with or receiving treatments for infertility, rather than in the general population. STUDY DESIGN, SIZE, DURATION: This was a multi-center pregnancy-based cohort study of 5628 nulliparous women with low-risk singleton pregnancies who participated in the Screening for Pregnancy Endpoints (SCOPE) study. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 5598 women were included. Data on retrospectively reported TTP and preconception dietary intake were collected during the first antenatal study visit (14-16 weeks' gestation). Dietary information for the 1 month prior to conception was obtained from food frequency questions for fruit, green leafy vegetables, fish and fast foods, by a research midwife. Use of any fertility treatments associated with the current pregnancy was documented (yes, n = 340, no, n = 5258). Accelerated failure time models with log normal distribution were conducted to estimate time ratios (TR) and 95% CIs. The impact of differences in dietary intake on infertility (TTP >12 months) was compared using a generalized linear model (Poisson distribution) with robust variance estimates, with resulting relative risks (RR) and 95% CIs. All analyses were controlled for a range of maternal and paternal confounders. Sensitivity analyses were conducted to explore potential biases common to TTP studies. MAIN RESULTS AND THE ROLE OF CHANCE: Lower intakes of fruit and higher intakes of fast food were both associated with modest increases in TTP and infertility. Absolute differences between the lowest and highest categories of intake for fruit and fast food were in the order of 0.6-0.9 months for TTP and 4-8% for infertility. Compared with women who consumed fruit ≥3 times/day, the adjusted effects of consuming fruit ≥1-<3 times/day (TR = 1.06, 95% CI: 0.97-1.15), 1-6 times/week (TR = 1.11, 95% CI: 1.01-1.22) or <1-3 times/month (TR = 1.19, 95% CI: 1.03-1.36), corresponded to 6, 11 and 19% increases in the median TTP (Ptrend = 0.007). Similarly, compared with women who consumed fast food ≥4 times/week, the adjusted effects of consuming fast food ≥2-<4 times/week (TR = 0.89, 95% CI: 0.81-0.98), >0-<2 times/week (TR 0.79, 95% CI 0.69-0.89) or no fast food (TR = 0.76, 95% CI: 0.61-0.95), corresponded to an 11, 21 and 24% reduction in the median TTP (Ptrend <0.001). For infertility, compared with women who consumed fruit ≥3 times/day, the adjusted effects of consuming fruit ≥1-<3 times/day, 1-6 times/week or <1-3 times/month corresponded to a 7, 18 and 29% increase in risk of infertility (Ptrend = 0.043). Similarly, compared with women who consumed fast food ≥4 times/week, the adjusted effects of consuming fast food ≥2-<4 times/week, >0-<2 times/week, or no fast food, corresponded to an 18, 34 and 41% reduced risk of infertility (Ptrend <0.001). Pre-pregnancy intake of green leafy vegetables or fish were not associated with TTP or infertility. Estimates remained stable across a range of sensitivity analyses. LIMITATIONS, REASONS FOR CAUTION: Collection of dietary data relied on retrospective recall and evaluated a limited range of foods. Paternal dietary data was not collected and the potential for residual confounding cannot be eliminated. Compared to prospective TTP studies, retrospective TTP studies are prone to a number of potential sources of bias. WIDER IMPLICATIONS OF THE FINDINGS: These findings underscore the importance of considering preconception diet for fecundity outcomes and preconception guidance. Further research is needed assessing a broader range of foods and food groups in the preconception period. STUDY FUNDING/COMPETING INTEREST(S): The SCOPE database is provided and maintained by MedSciNet AB (http://medscinet.com). The Australian SCOPE study was funded by the Premier's Science and Research Fund, South Australian Government (http://www.dfeest.sa.gov.au/science-research/premiers-research-and-industry-fund). The New Zealand SCOPE study was funded by the New Enterprise Research Fund, Foundation for Research Science and Technology; Health Research Council (04/198); Evelyn Bond Fund, Auckland District Health Board Charitable Trust. The Irish SCOPE study was funded by the Health Research Board of Ireland (CSA/2007/2; http://www.hrb.ie). The UK SCOPE study was funded by National Health Service NEAT Grant (Neat Grant FSD025), Biotechnology and Biological Sciences Research council (www.bbsrc.ac.uk/funding; GT084) and University of Manchester Proof of Concept Funding (University of Manchester); Guy's and St. Thomas' Charity (King's College London) and Tommy's charity (http://www.tommys.org/; King's College London and University of Manchester); and Cerebra UK (www.cerebra.org.uk; University of Leeds). L.E.G. is supported by an Australian National Health and Medical Research Council (NHMRC) Early Career Fellowship (ID 1070421). L.J.M. is supported by a SACVRDP Fellowship; a program collaboratively funded by the National Heart Foundation, the South Australian Department of Health and the South Australian Health and Medical Research Institute. L.C.K. is supported by a Science Foundation Ireland Program Grant for INFANT (12/RC/2272). C.T.R. was supported by a National Health and Medical Research Council (NHMRC) Senior Research Fellowship (GNT1020749). There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Vitamin D levels in an Australian and New Zealand cohort and the association with pregnancy outcome.

BACKGROUND: Pregnant women are at increased susceptibility to vitamin D deficiency. Hence, there is continuing interest in determining how vitamin D influences pregnancy health. We aimed to compare vitamin D status in two distinct populations of pregnant women in Australia and New Zealand and to investigate the relationship between vitamin D status and pregnancy outcome. This included evaluating possible effect measure modifications according to fetal sex. METHODS: Serum 25-hydroxy vitamin D (25(OH)D) was measured at 15 ± 1 weeks' gestation in 2800 women from Adelaide and Auckland who participated in the multi-centre, prospective cohort SCreening fOr Pregnancy Endpoints (SCOPE) study. RESULTS: Mean serum 25(OH)D in all women was 68.1 ± 27.1 nmol/L and 28% (n = 772) were considered vitamin D deficient (< 50 nmol/L). Serum 25(OH)D was lower in the women recruited in Adelaide when compared to the women recruited in Auckland and remained lower after adjusting for covariates including maternal body mass index and socioeconomic index (Adelaide: 58.4 ± 50.3 vs. Auckland: 70.2 ± 54.5 nmol/L, P < 0.001). A 53% decreased risk for gestational diabetes mellitus (GDM) was observed with high (> 81 nmol/L) "standardised" vitamin D status when compared to moderate-high (63-81 nmol/L, aRR, 0.47; 95% CI: 0.23, 0.96). Marginal sex-specific differences occurred between vitamin D status and GDM: women carrying a female fetus had a 56% decreased risk for GDM in those with low-moderate levels of standardised vitamin D (44-63 nmol/L) compared to moderate-high levels (aRR: 0.44; 95% CI: 0.20, 0.97), whilst in women carrying a male fetus, a 55% decreased risk of GDM was found with high standardised vitamin D when compared to moderately-high vitamin D, but this was not statistically significant (aRR: 0.45; 95% CI: 0.15, 1.38). CONCLUSIONS: High serum 25(OH)D at 15 ± 1 weeks' gestation was shown to be protective against the development of GDM. A possible association between fetal sex, vitamin D status and GDM provides further questions and encourages continual research and discussion into the role of vitamin D in pregnancy, particularly in vitamin D replete populations.

Placental transcriptome co-expression analysis reveals conserved regulatory programs across gestation.

BACKGROUND: Mammalian development in utero is absolutely dependent on proper placental development, which is ultimately regulated by the placental genome. The regulation of the placental genome can be directly studied by exploring the underlying organisation of the placental transcriptome through a systematic analysis of gene-wise co-expression relationships. RESULTS: In this study, we performed a comprehensive analysis of human placental co-expression using RNA sequencing and intergrated multiple transcriptome datasets spanning human gestation. We identified modules of co-expressed genes that are preserved across human gestation, and also identifed modules conserved in the mouse indicating conserved molecular networks involved in placental development and gene expression patterns more specific to late gestation. Analysis of co-expressed gene flanking sequences indicated that conserved co-expression modules in the placenta are regulated by a core set of transcription factors, including ZNF423 and EBF1. Additionally, we identified a gene co-expression module enriched for genes implicated in the pregnancy pathology preeclampsia. By using an independnet transcriptome dataset, we show that these co-expressed genes are differentially expressed in preeclampsia. CONCLUSIONS: This study represents a comprehensive characterisation of placental co-expression and provides insight into potential transcriptional regulators that govern conserved molecular programs fundamental to placental development.

Mechanistic Insight into Long Noncoding RNAs and the Placenta.

Long non-coding RNAs (lncRNAs) are classified as RNAs greater than 200 nucleotides in length that do not produce a protein product. lncRNAs are expressed with cellular and temporal specificity and have been shown to play a role in many cellular events, including the regulation of gene expression, post-transcriptional modifications and epigenetic modifications. Since lncRNAs were first discovered, there has been increasing evidence that they play important roles in the development and function of most organs, including the placenta. The placenta is an essential transient organ that facilitates communication and nutrient exchange between the mother and foetus. The placenta is of foetal origin and begins to form shortly after the embryo implants into the uterine wall. The placenta relies heavily on the successful differentiation and function of trophoblast cells, including invasion as well as the formation of the maternal/foetal interface. Here, we review the current literature surrounding the involvement of lncRNAs in the development and function of trophoblasts and the human placenta.

Recent progress towards understanding the role of DNA methylation in human placental development.

Epigenetic modifications, and particularly DNA methylation, have been studied in many tissues, both healthy and diseased, and across numerous developmental stages. The placenta is the only organ that has a transient life of 9 months and undergoes rapid growth and dynamic structural and functional changes across gestation. Additionally, the placenta is unique because although developing within the mother, its genome is identical to that of the foetus. Given these distinctive characteristics, it is not surprising that the epigenetic landscape affecting placental gene expression may be different to that in other healthy tissues. However, the role of epigenetic modifications, and particularly DNA methylation, in placental development remains largely unknown. Of particular interest is the fact that the placenta is the most hypomethylated human tissue and is characterized by the presence of large partially methylated domains (PMDs) containing silenced genes. Moreover, how and why the placenta is hypomethylated and what role DNA methylation plays in regulating placental gene expression across gestation are poorly understood. We review genome-wide DNA methylation studies in the human placenta and highlight that the different cell types that make up the placenta have very different DNA methylation profiles. Summarizing studies on DNA methylation in the placenta and its relationship with pregnancy complications are difficult due to the limited number of studies available for comparison. To understand the key steps in placental development and hence what may be perturbed in pregnancy complications requires large-scale genome-wide DNA methylation studies coupled with transcriptome analyses.

massiR: a method for predicting the sex of samples in gene expression microarray datasets.

UNLABELLED: High-throughput gene expression microarrays are currently the most efficient method for transcriptome-wide expression analyses. Consequently, gene expression data available through public repositories have largely been obtained from microarray experiments. However, the metadata associated with many publicly available expression microarray datasets often lacks sample sex information, therefore limiting the reuse of these data in new analyses or larger meta-analyses where the effect of sex is to be considered. Here, we present the massiR package, which provides a method for researchers to predict the sex of samples in microarray datasets. Using information from microarray probes representing Y chromosome genes, this package implements unsupervised clustering methods to classify samples into male and female groups, providing an efficient way to identify or confirm the sex of samples in mammalian microarray datasets. AVAILABILITY AND IMPLEMENTATION: massiR is implemented as a Bioconductor package in R. The package and the vignette can be downloaded at bioconductor.org and are provided under a GPL-2 license.

Integrative transcriptome meta-analysis reveals widespread sex-biased gene expression at the human fetal-maternal interface.

As males and females share highly similar genomes, the regulation of many sexually dimorphic traits is constrained to occur through sex-biased gene regulation. There is strong evidence that human males and females differ in terms of growth and development in utero and that these divergent growth strategies appear to place males at increased risk when in sub-optimal conditions. Since the placenta is the interface of maternal-fetal exchange throughout pregnancy, these developmental differences are most likely orchestrated by differential placental function. To date, progress in this field has been hampered by a lack of genome-wide information on sex differences in placental gene expression. Therefore, our motivation in this study was to characterize sex-biased gene expression in the human placenta. We obtained gene expression data for >300 non-pathological placenta samples from 11 microarray datasets and applied mapping-based array probe re-annotation and inverse-variance meta-analysis methods which showed that >140 genes (false discovery rate (FDR) <0.05) are differentially expressed between male and female placentae. A majority of these genes (>60%) are autosomal, many of which are involved in high-level regulatory processes such as gene transcription, cell growth and proliferation and hormonal function. Of particular interest, we detected higher female expression from all seven genes in the LHB-CGB cluster, which includes genes involved in placental development, the maintenance of pregnancy and maternal immune tolerance of the conceptus. These results demonstrate that sex-biased gene expression in the normal human placenta occurs across the genome and includes genes that are central to growth, development and the maintenance of pregnancy.

Imprinted gene alterations in the kidneys of growth restricted offspring may be mediated by a long non-coding RNA.

Altered epigenetic mechanisms have been previously reported in growth restricted offspring whose mothers experienced environmental insults during pregnancy in both human and rodent studies. We previously reported changes in the expression of the DNA methyltransferase Dnmt3a and the imprinted genes Cdkn1c (Cyclin-dependent kinase inhibitor 1C) and Kcnq1 (Potassium voltage-gated channel subfamily Q member 1) in the kidney tissue of growth restricted rats whose mothers had uteroplacental insufficiency induced on day 18 of gestation, at both embryonic day 20 (E20) and postnatal day 1 (PN1). To determine the mechanisms responsible for changes in the expression of these imprinted genes, we investigated DNA methylation of KvDMR1, an imprinting control region (ICR) that includes the promoter of the antisense long non-coding RNA Kcnq1ot1 (Kcnq1 opposite strand/antisense transcript 1). Kcnq1ot1 expression decreased by 51% in growth restricted offspring compared to sham at PN1. Interestingly, there was a negative correlation between Kcnq1ot1 and Kcnq1 in the E20 growth restricted group (Spearman's ρ = 0.014). No correlation was observed between Kcnq1ot1 and Cdkn1c expression in either group at any time point. Additionally, there was a 11.25% decrease in the methylation level at one CpG site within KvDMR1 ICR. This study, together with others in the literature, supports that long non-coding RNAs may mediate changes seen in tissues of growth restricted offspring.

Characterization of the prostate cancer susceptibility gene KLF6 in human and mouse prostate cancers.

BACKGROUND: Krüppel-like factor (KLF) 6 is a candidate tumor suppressor gene in prostate cancer, but the mechanisms contributing to its loss of expression are poorly understood. We characterized KLF6 expression and DNA methylation status during prostate tumorigenesis in humans and mice. METHODS: KLF6 expression was assessed in matched human non-malignant (NM) and tumor prostate tissues (n = 22) by quantitative real-time PCR (qPCR) and in three independent human prostate cancer cohorts bioinformatically. QPCR for KLF6 expression and methylation-sensitive PCR (MSP) were performed in human prostate LNCaP cancer cells after 5-aza-2'-deoxycytidine treatment. Klf6 protein levels and DNA promoter methylation were assessed in TRansgenic Adenocarcinoma of Mouse Prostate (TRAMP) tumors by immunohistochemistry and MSP, respectively. RESULTS: KLF6 splice variants expression was increased (P = 0.0015) in human prostate tumors compared to NM tissues. Overall, KLF6 was decreased in metastatic compared to primary prostate cancers and reduced expression in primary tumors was associated with a shorter time to relapse (P = 0.0028). Treatment with the demethylating agent 5-aza-2'-deoxycytidine resulted in up-regulation of KLF6 expression (two-fold; P = 0.002) and a decrease in DNA methylation of the KLF6 promoter in LNCaP cells. Klf6 protein levels significantly decreased with progression in the TRAMP model of prostate cancer (P < 0.05), but there was no difference in Klf6 promoter methylation. CONCLUSION: KLF6 expression was decreased in both clinical prostate cancer and the TRAMP model with disease progression, but this could not be explained by DNA methylation of the KLF6 promoter.