The metabolic health of young men conceived using intracytoplasmic sperm injection

STUDY QUESTION

Is the metabolic health of men conceived using ICSI different to that of IVF and spontaneously conceived (SC) men?

SUMMARY ANSWER

ICSI-conceived men aged 18-24 years, compared with SC controls, showed differences in some metabolic parameters including higher resting diastolic blood pressure (BP) and homeostasis model assessment for insulin resistance (HOMA-IR) scores, although the metabolic parameters of ICSI- and IVF-conceived singleton men were more comparable.

WHAT IS KNOWN ALREADY

Some studies suggest that IVF-conceived offspring may have poorer cardiovascular and metabolic profiles than SC children. Few studies have examined the metabolic health of ICSI-conceived offspring.

STUDY DESIGN, SIZE, DURATION

This cohort study compared the metabolic health of ICSI-conceived men to IVF-conceived and SC controls who were derived from prior cohorts. Participants included 121 ICSI-conceived men (including 100 singletons), 74 IVF-conceived controls (all singletons) and 688 SC controls (including 662 singletons).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Resting systolic and diastolic BP (measured using an automated sphygmomanometer), height, weight, BMI, body surface area and fasting serum metabolic markers including fasting insulin, glucose, total cholesterol, high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol, triglycerides, highly sensitive C-reactive protein (hsCRP) and HOMA-IR were compared between groups. Data were analysed using multivariable linear regression adjusted for various covariates including age and education level.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjusting for covariates, compared to 688 SC controls, 121 ICSI-conceived men had higher diastolic BP (β 4.9, 95% CI 1.1-8.7), lower fasting glucose (β -0.7, 95% CI -0.9 to -0.5), higher fasting insulin (ratio 2.2, 95% CI 1.6-3.0), higher HOMA-IR (ratio 1.9, 95% CI 1.4-2.6), higher HDLC (β 0.2, 95% CI 0.07-0.3) and lower hsCRP (ratio 0.4, 95% CI 0.2-0.7) levels. Compared to 74 IVF-conceived singletons, only glucose differed in the ICSI-conceived singleton men (β -0.4, 95% CI -0.7 to -0.1). No differences were seen in the paternal infertility subgroups.

LIMITATIONS, REASONS FOR CAUTION

The recruitment rate of ICSI-conceived men in this study was low and potential for recruitment bias exists. The ICSI-conceived men, the IVF-conceived men and SC controls were from different cohorts with different birth years and different geographical locations. Assessment of study groups and controls was not contemporaneous, and the measurements differed for some outcomes (BP, insulin, glucose, lipids and hsCRP).

WIDER IMPLICATIONS OF THE FINDINGS

These observations require confirmation in a larger study with a focus on potential mechanisms. Further efforts to identify whether health differences are due to parental characteristics and/or factors related to the ICSI procedure are also necessary.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by an Australian National Health and Medical Research Council Partnership Grant (NHMRC APP1140706) and was partially funded by the Monash IVF Research and Education Foundation. S.R.C. was supported through an Australian Government Research Training Program Scholarship. R.J.H. is supported by an NHMRC project grant (634457), and J.H. and R.I.M. have been supported by the NHMRC as Senior and Principal Research Fellows respectively (J.H. fellowship number: 1021252; R.I.M. fellowship number: 1022327). L.R. is a minority shareholder and the Group Medical Director for Monash IVF Group, and reports personal fees from Monash IVF Group and Ferring Australia, honoraria from Ferring Australia and travel fees from Merck Serono and MSD and Guerbet; R.J.H. is the Medical Director of Fertility Specialists of Western Australia and has equity in Western IVF; R.I.M. is a consultant for and shareholder of Monash IVF Group and S.R.C. reports personal fees from Besins Healthcare and nonfinancial support from Merck outside of the submitted work. The remaining authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Functional and transcriptional differences in monocytes from children with obesity compared to children of healthy weight

Background and aim

Cardiometabolic risk accrues across the entire life course and childhood is a key epoch for effective prevention. Obesity in childhood is the most prevalent modifiable risk factor for later cardiovascular disease (CVD). Inflammatory biomarkers and innate immune capacity are increased in adults with obesity, but childhood data are scarce. We aimed to investigate (i) innate immune cell activation in children with and without obesity; and (ii) whether weight loss impacts the innate immune inflammatory phenotype.

Methods

The innate immune phenotype of Peripheral Blood Mononuclear Cells (PBMCs) from 31 children with obesity (BMI z-score>2.5) and 22 children of healthy weight (−1.5≤BMIz≤1.5, sex, age and pubertal stage matched) was characterized by high dimensional flow cytometry, ex vivo stimulation assays with subsequent 27-plex cytokine measurements, and transcriptome analysis using RNA sequencing (Figure 1). Children with obesity participated to the Royal Children's Hospital Weight Management Service (median 5 years) and at follow-up, PBMCs were obtained again as well as anthropometric data and subclinical cardiovascular phenotypes.

Results

Flow cytometric analysis showed marked differences in cell composition between children with obesity and children of healthy weight. Specifically, children with obesity have significant changes in monocyte subsets and an increased expression of monocyte activation markers. Upon stimulation, monocytes of children with obesity show an increased cytokine production capacity. Finally, transcriptomic analysis shows significant differences between monocytes from obese children and healthy controls. Effects of weight loss on these immune parameters and correlations with preclinical CVD phenotypes are currently being analysed.

Conclusions

Monocytes from children with obesity have a pro-inflammatory phenotype compared to children of normal weight. Heightened inflammation may contribute to increased CVD risk later in life and may offer opportunities for early intervention.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Dutch Scientific Organisation (NWO) - Rubicon grant to S.B. Dutch Heart Foundation - CVON IN CONTROL II to N.P.R. and D.B. Figure 1. Schematical overview of study

Accelerated Epigenetic Aging in Peripheral Blood does not Predict Dementia Risk

BACKGROUND

There is strong evidence that epigenetic age acceleration is associated with increased risk of later-life diseases and all-cause mortality. However, there is currently limited evidence that suggests accelerated epigenetic age is associated with dementia risk.

OBJECTIVE

This study aims to clarify whether epigenetic biomarkers of accelerated aging can predict dementia risk, which is an important consideration as aging is the greatest risk factor for the disease.

METHODS

DNA methylation was measured in peripheral blood samples provided by 160 participants from the ASPirin in Reducing Events in the Elderly study, including 73 pre-symptomatic dementia cases and 87 controls matched for age, sex, and smoking and education status. Epigenetic age was calculated using Horvath, Hannum, GrimAge and PhenoAge DNA methylation clocks, and age acceleration (the disparity between chronological age and epigenetic age) was determined.

RESULTS

There was no difference in age acceleration between dementia cases and controls. In males, only Hannum's intrinsic epigenetic age acceleration was increased in pre-symptomatic dementia cases compared to controls (Δ +1.8 years, p = 0.03).

CONCLUSION

These findings provide no strong evidence that accelerated epigenetic aging measured in peripheral blood can predict dementia risk.

Health and fertility of ICSI-conceived young men: study protocol

STUDY QUESTIONS

What are the long-term health and reproductive outcomes for young men conceived using ICSI whose fathers had spermatogenic failure (STF)? Are there epigenetic consequences of ICSI conception?

WHAT IS KNOWN ALREADY

Currently, little is known about the health of ICSI-conceived adults, and in particular the health and reproductive potential of ICSI-conceived men whose fathers had STF. Only one group to date has assessed semen parameters and reproductive hormones in ICSI-conceived men and suggested higher rates of impaired semen quality compared to spontaneously conceived (SC) peers. Metabolic parameters in this same cohort of men were mostly comparable. No study has yet evaluated other aspects of adult health.

STUDY DESIGN SIZE DURATION

This cohort study aims to evaluate the general health and development (aim 1), fertility and metabolic parameters (aim 2) and epigenetic signatures (aim 3) of ICSI-conceived sons whose fathers had STF (ICSI study group). There are three age-matched control groups: ICSI-conceived sons whose fathers had obstructive azoospermia (OAZ) and who will be recruited in this study, as well as IVF sons and SC sons, recruited from other studies. Of 1112 ICSI parents including fathers with STF and OAZ, 78% (n = 867) of mothers and 74% (n = 823) of fathers were traced and contacted. Recruitment of ICSI sons started in March 2017 and will finish in July 2020. Based on preliminary participation rates, we estimate the following sample size will be achieved for the ICSI study group: mothers n = 275, fathers n = 225, sons n = 115. Per aim, the sample sizes of OAZ-ICSI (estimated), IVF and SC controls are: Aim 1-OAZ-ICSI: 28 (maternal surveys)/12 (son surveys), IVF: 352 (maternal surveys)/244 (son surveys), SC: 428 (maternal surveys)/255 (son surveys); Aim 2-OAZ-ICSI: 12, IVF: 72 (metabolic data), SC: 391 (metabolic data)/365 (reproductive data); Aim 3-OAZ-ICSI: 12, IVF: 71, SC: 292.

PARTICIPANTS/MATERIALS SETTING METHODS

Eligible parents are those who underwent ICSI at one of two major infertility treatment centres in Victoria, Australia and gave birth to one or more males between January 1994 and January 2000. Eligible sons are those aged 18 years or older, whose fathers had STF or OAZ, and whose parents allow researchers to approach sons. IVF and SC controls are age-matched men derived from previous studies, some from the same source population. Participating ICSI parents and sons complete a questionnaire, the latter also undergoing a clinical assessment. Outcome measures include validated survey questions, physical examination (testicular volumes, BMI and resting blood pressure), reproductive hormones (testosterone, sex hormone-binding globulin, FSH, LH), serum metabolic parameters (fasting glucose, insulin, lipid profile, highly sensitive C-reactive protein) and semen analysis. For epigenetic and future genetic analyses, ICSI sons provide specimens of blood, saliva, sperm and seminal fluid while their parents provide a saliva sample. The primary outcomes of interest are the number of mother-reported hospitalisations of the son; son-reported quality of life; prevalence of moderate-severe oligozoospermia (sperm concentration <5 million/ml) and DNA methylation profile. For each outcome, differences between the ICSI study group and each control group will be investigated using multivariable linear and logistic regression for continuous and binary outcomes, respectively. Results will be presented as adjusted odds ratios and 95% CIs.

STUDY FUNDING/COMPETING INTERESTS

This study is funded by an Australian National Health and Medical Research Council Partnership Grant (NHMRC APP1140706) and was partially funded by the Monash IVF Research and Education Foundation. L.R. is a minority shareholder and the Group Medical Director for Monash IVF Group, and reports personal fees from Monash IVF group and Ferring Australia, honoraria from Ferring Australia, and travel fees from Merck Serono, MSD and Guerbet; R.J.H. is the Medical Director of Fertility Specialists of Western Australia and has equity in Western IVF; R.I.M. is a consultant for and a shareholder of Monash IVF Group and S.R.C. reports personal fees from Besins Healthcare and non-financial support from Merck outside of the submitted work. The remaining authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

TRIAL REGISTRATION DATE

Not applicable.

DATE OF FIRST PATIENT’S ENROLMENT

Not applicable.

A twin study of body mass index and dental caries in childhood

Sub-optimal nutrition and dental caries are both common with significant short and long-term implications for child health and development. We applied twin statistical methods to explore the relationship between body mass index (BMI) and dental caries. We measured BMI at 18 months and six years of age and cumulative dental caries experience at six years in 344 twin children. Dental caries in primary teeth was categorised into ‘any’ or ‘advanced’ and BMI was analysed as both a continuous and categorical variable. Statistical analyses included multiple logistic regression using generalized estimating equations and within/between-pair analyses. There was no association between BMI and ‘any’ dental caries experience at either time-point, neither overall nor in within/between pair analyses. However, ‘advanced’ dental caries at six years was associated with a within-pair difference in BMI of −0.55 kg/m² (95% CI −1.00, −0.11, p = 0.015). A within-pair increase of 1 kg/m² in BMI was associated with a lower within-pair risk of advanced dental caries (OR 0.68, 95% CI 0.52, 0.90, p = 0.007). These findings reveal a possible causal relationship between lower BMI and dental caries. As dental outcomes were only measured at one time point, the direction of this potentially causal relationship is unclear.

Associations between birth size and later height from infancy through adulthood: An individual based pooled analysis of 28 twin cohorts participating in the CODATwins project

BACKGROUND

There is evidence that birth size is positively associated with height in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment.

AIM

To analyze the associations of birth weight, length and ponderal index with height from infancy through adulthood within mono- and dizygotic twin pairs, which provides insights into the role of genetic and environmental individual-specific factors.

METHODS

This study is based on the data from 28 twin cohorts in 17 countries. The pooled data included 41,852 complete twin pairs (55% monozygotic and 45% same-sex dizygotic) with information on birth weight and a total of 112,409 paired height measurements at ages ranging from 1 to 69 years. Birth length was available for 19,881 complete twin pairs, with a total of 72,692 paired height measurements. The association between birth size and later height was analyzed at both the individual and within-pair level by linear regression analyses.

RESULTS

Within twin pairs, regression coefficients showed that a 1-kg increase in birth weight and a 1-cm increase in birth length were associated with 1.14-4.25 cm and 0.18-0.90 cm taller height, respectively. The magnitude of the associations was generally greater within dizygotic than within monozygotic twin pairs, and this difference between zygosities was more pronounced for birth length.

CONCLUSION

Both genetic and individual-specific environmental factors play a role in the association between birth size and later height from infancy to adulthood, with a larger role for genetics in the association with birth length than with birth weight.

The association between higher maternal pre-pregnancy body mass index and increased birth weight, adiposity and inflammation in the newborn

BACKGROUND

Excess adiposity and adiposity-related inflammation are known risk factors for cardiovascular disease in adults; however, little is known regarding the determinants of adiposity-related inflammation at birth.

OBJECTIVES

The aim of this study was to investigate the association between maternal pre-pregnancy BMI and newborn adiposity and inflammation.

METHODS

Paired maternal (28-week gestation) and infant (umbilical cord) blood samples were collected from a population-derived birth cohort (Barwon Infant Study, n = 1074). Data on maternal comorbidities and infant birth anthropomorphic measures were compiled, and infant aortic intima-media thickness was measured by trans-abdominal ultrasound. In a selected subgroup of term infants (n = 161), matched maternal and cord lipids, high-sensitivity C-reactive protein (hsCRP) and maternal soluble CD14 were measured. Analysis was completed by using pairwise correlation and linear regression. Because of their non-normal distribution, pathology blood measures were log transformed prior to analysis.

RESULTS

Maternal pre-pregnancy BMI was positively associated with increased birth weight (mean difference 17.8 g per kg m^-2 , 95% CI 6.6 to 28.9; p = 0.002), newborn mean skin-fold thickness (mean difference 0.1 mm per kg m^-2 , 95% CI 0.0 to 0.1; p < 0.001) and cord blood hsCRP (mean difference of 4.2% increase in hsCRP per kg m^-2 increase in pre-pregnancy BMI, 95% CI 0.6 to 7.7%, p = 0.02), but not cord blood soluble CD14. Inclusion of maternal hsCRP as a covariate attenuated the associations between pre-pregnancy BMI and both newborn skin-fold thickness and cord blood hsCRP.

CONCLUSION

Higher maternal pre-pregnancy BMI is associated with increased newborn adiposity and inflammation. These associations may be partially mediated by maternal inflammation during pregnancy.

DNA methylation of amino acid transporter genes in the human placenta

INTRODUCTION

Placental transfer of amino acids via amino acid transporters is essential for fetal growth. Little is known about the epigenetic regulation of amino acid transporters in placenta. This study investigates the DNA methylation status of amino acid transporters and their expression across gestation in human placenta.

METHODS

BeWo cells were treated with 5-aza-2'-deoxycytidine to inhibit methylation and assess the effects on amino acid transporter gene expression. The DNA methylation levels of amino acid transporter genes in human placenta were determined across gestation using DNA methylation array data. Placental amino acid transporter gene expression across gestation was also analysed using data from publically available Gene Expression Omnibus data sets. The expression levels of these transporters at term were established using RNA sequencing data.

RESULTS

Inhibition of DNA methylation in BeWo cells demonstrated that expression of specific amino acid transporters can be inversely associated with DNA methylation. Amino acid transporters expressed in term placenta generally showed low levels of promoter DNA methylation. Transporters with little or no expression in term placenta tended to be more highly methylated at gene promoter regions. The transporter genes SLC1A2, SLC1A3, SLC1A4, SLC7A5, SLC7A11 and SLC7A10 had significant changes in enhancer DNA methylation across gestation, as well as gene expression changes across gestation.

CONCLUSION

This study implicates DNA methylation in the regulation of amino acid transporter gene expression. However, in human placenta, DNA methylation of these genes remains low across gestation and does not always play an obvious role in regulating gene expression, despite clear evidence for differential expression as gestation proceeds.

The skin barrier function gene SPINK5 is associated with challenge-proven IgE-mediated food allergy in infants

BACKGROUND

A defective skin barrier is hypothesized to be an important route of sensitization to dietary antigens and may lead to food allergy in some children. Missense mutations in the serine peptidase inhibitor Kazal type 5 (SPINK5) skin barrier gene have previously been associated with allergic conditions.

OBJECTIVE

To determine whether genetic variants in and around SPINK5 are associated with IgE-mediated food allergy.

METHOD

We genotyped 71 "tag" single nucleotide polymorphisms (tag-SNPs) within a region spanning ~263 kb including SPINK5 (~61 kb) in n=722 (n=367 food-allergic, n=199 food-sensitized-tolerant and n=156 non-food-allergic controls) 12-month-old infants (discovery sample) phenotyped for food allergy with the gold standard oral food challenge. Transepidermal water loss (TEWL) measures were collected at 12 months from a subset (n=150) of these individuals. SNPs were tested for association with food allergy using the Cochran-Mantel-Haenszel test adjusting for ancestry strata. Association analyses were replicated in an independent sample group derived from four paediatric cohorts, total n=533 (n=203 food-allergic, n=330 non-food-allergic), mean age 2.5 years, with food allergy defined by either clinical history of reactivity, 95% positive predictive value (PPV) or challenge, corrected for ancestry by principal components.

RESULTS

SPINK5 variant rs9325071 (A⟶G) was associated with challenge-proven food allergy in the discovery sample (P=.001, OR=2.95, CI=1.49-5.83). This association was further supported by replication (P=.007, OR=1.58, CI=1.13-2.20) and by meta-analysis (P=.0004, OR=1.65). Variant rs9325071 is associated with decreased SPINK5 gene expression in the skin in publicly available genotype-tissue expression data, and we generated preliminary evidence for association of this SNP with elevated TEWL also.

CONCLUSIONS

We report, for the first time, association between SPINK5 variant rs9325071 and challenge-proven IgE-mediated food allergy.

Vitamin D insufficiency in the first 6 months of infancy and challenge-proven IgE-mediated food allergy at 1 year of age: a case-cohort study

BACKGROUND

Ecological evidence suggests vitamin D insufficiency (VDI) due to lower ambient ultraviolet radiation (UVR) exposure may be a risk factor for IgE-mediated food allergy. However, there are no studies relating directly measured VDI during early infancy to subsequent challenge-proven food allergy.

OBJECTIVE

To prospectively investigate the association between VDI during infancy and challenge-proven food allergy at 1 year.

METHODS

In a birth cohort (n = 1074), we used a case-cohort design to compare 25-hydroxyvitamin D₃ (25(OH)D₃ ) levels among infants with food allergy vs a random subcohort (n = 274). The primary exposures were VDI (25(OH)D₃ <50 nM) at birth and 6 months of age. Ambient UVR and time in the sun were combined to estimate UVR exposure dose. IgE-mediated food allergy status at 1 year was determined by formal challenge. Binomial regression was used to examine associations between VDI, UVR exposure dose and food allergy and investigate potential confounding.

RESULTS

Within the random subcohort, VDI was present in 45% (105/233) of newborns and 24% (55/227) of infants at 6 months. Food allergy prevalence at 1 year was 7.7% (61/786), and 6.5% (53/808) were egg-allergic. There was no evidence of an association between VDI at either birth (aRR 1.25, 95% CI 0.70-2.22) or 6 months (aRR 0.93, 95% CI 0.41-2.14) and food allergy at 1 year.

CONCLUSIONS

There was no evidence that VDI during the first 6 months of infancy is a risk factor for food allergy at 1 year of age. These findings primarily relate to egg allergy, and larger studies are required.

Genetic variation at the Th2 immune gene IL13 is associated with IgE-mediated paediatric food allergy

BACKGROUND

Food allergies pose a considerable world-wide public health burden with incidence as high as one in ten in 12-month-old infants. Few food allergy genetic risk variants have yet been identified. The Th2 immune gene IL13 is a highly plausible genetic candidate as it is central to the initiation of IgE class switching in B cells.

OBJECTIVE

Here, we sought to investigate whether genetic polymorphisms at IL13 are associated with the development of challenge-proven IgE-mediated food allergy.

METHOD

We genotyped nine IL13 "tag" single nucleotide polymorphisms (tag SNPs) in 367 challenge-proven food allergic cases, 199 food-sensitized tolerant cases and 156 non-food allergic controls from the HealthNuts study. 12-month-old infants were phenotyped using open oral food challenges. SNPs were tested using Cochran-Mantel-Haenszel test adjusted for ancestry strata. A replication study was conducted in an independent, co-located sample of four paediatric cohorts consisting of 203 food allergic cases and 330 non-food allergic controls. Replication sample phenotypes were defined by clinical history of reactivity, 95% PPV or challenge, and IL13 genotyping was performed.

RESULTS

IL13 rs1295686 was associated with challenge-proven food allergy in the discovery sample (P=.003; OR=1.75; CI=1.20-2.53). This association was also detected in the replication sample (P=.03, OR=1.37, CI=1.03-1.82) and further supported by a meta-analysis (P=.0006, OR=1.50). However, we cannot rule out an association with food sensitization. Carriage of the rs1295686 variant A allele was also associated with elevated total plasma IgE.

CONCLUSIONS AND CLINICAL RELAVANCE

We show for the first time, in two independent cohorts, that IL13 polymorphism rs1295686 (in complete linkage disequilibrium with functional variant rs20541) is associated with challenge-proven food allergy.

The effects of maternal anxiety during pregnancy on IGF2/H19 methylation in cord blood

Compelling evidence suggests that maternal mental health in pregnancy can influence fetal development. The imprinted genes, insulin-like growth factor 2 (IGF2) and H19, are involved in fetal growth and each is regulated by DNA methylation. This study aimed to determine the association between maternal mental well-being during pregnancy and differentially methylated regions (DMRs) of IGF2 (DMR0) and the IGF2/H19 imprinting control region (ICR) in newborn offspring. Maternal depression, anxiety and perceived stress were assessed at 28 weeks of pregnancy in the Barwon Infant Study (n=576). DNA methylation was measured in purified cord blood mononuclear cells using the Sequenom MassArray Platform. Maternal anxiety was associated with a decrease in average ICR methylation (Δ=-2.23%; 95% CI=-3.68 to -0.77%), and across all six of the individual CpG units in anxious compared with non-anxious groups. Birth weight and sex modified the association between prenatal anxiety and infant methylation. When stratified into lower (⩽3530 g) and higher (>3530 g) birth weight groups using the median birth weight, there was a stronger association between anxiety and ICR methylation in the lower birth weight group (Δ=-3.89%; 95% CI=-6.06 to -1.72%), with no association in the higher birth weight group. When stratified by infant sex, there was a stronger association in female infants (Δ=-3.70%; 95% CI=-5.90 to -1.51%) and no association in males. All the linear regression models were adjusted for maternal age, smoking and folate intake. These findings show that maternal anxiety in pregnancy is associated with decreased IGF2/H19 ICR DNA methylation in progeny at birth, particularly in female, low birth weight neonates. ICR methylation may help link poor maternal mental health and adverse birth outcomes, but further investigation is needed.

IFPA meeting 2015 workshop report III: nanomedicine applications and exosome biology, xenobiotics and endocrine disruptors and pregnancy, and lipid

Workshops are an important part of the IFPA annual meeting, as they allow for discussion of specialized topics. At the IFPA meeting 2015 there were twelve themed workshops, three of which are summarized in this report. These workshops were related to various aspects of placental biology but collectively covered areas of pregnancy pathologies and placental metabolism: 1) nanomedicine applications and exosome biology; 2) xenobiotics and endocrine disruptors and pregnancy; 3) lipid mediators and placental function.

IFPA meeting 2015 workshop report I: placental mitochondrial function, transport systems and epigenetics

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2015 there were twelve themed workshops, three of which are summarized in this report. These workshops covered areas of placental regulation and nutrient handling: 1) placental epigenetics; 2) placental mitochondrial function; 3) placental transport systems.

BDNF promoter methylation and genetic variation in late-life depression

The regulation of the brain-derived neurotrophic factor (BDNF) is important for depression pathophysiology and epigenetic regulation of the BDNF gene may be involved. This study investigated whether BDNF methylation is a marker of depression. One thousand and twenty-four participants were recruited as part of a longitudinal study of psychiatric disorders in general population elderly (age ⩾ 65). Clinical levels of depression were assessed using the Mini International Neuropsychiatric Interview for the diagnosis of major depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorder IV criteria, and the Centre for Epidemiologic Studies Depression Scale (CES-D) for assessment of moderate to severe depressive symptoms. Buccal DNA methylation at the two most widely studied BDNF promoters, I and IV, was investigated using the Sequenom MassARRAY platform that allows high-throughput investigation of methylation at individual CpG sites within defined genomic regions. In multivariate linear regression analyses adjusted for a range of participant characteristics including antidepressant use, depression at baseline, as well as chronic late-life depression over the 12-year follow-up, were associated with overall higher BDNF methylation levels, with two sites showing significant associations (promoter I, Δ mean = 0.4%, P = 0.0002; promoter IV, Δ mean = 5.4%, P = 0.021). Three single-nucleotide polymorphisms (rs6265, rs7103411 and rs908867) were also found to modify the association between depression and promoter I methylation. As one of the largest epigenetic studies of depression, and the first investigating BDNF methylation in buccal tissue, our findings highlight the potential for buccal BDNF methylation to be a biomarker of depression.

IFPA meeting 2014 workshop report: Animal models to study pregnancy pathologies; new approaches to study human placental exposure to xenobiotics; biomarkers of pregnancy pathologies; placental genetics and epigenetics; the placenta and stillbirth and fetal growth restriction

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2014 there were six themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of animal models, xenobiotics, pathological biomarkers, genetics and epigenetics, and stillbirth and fetal growth restriction.

The potential for epigenetic analysis of paediatric CNS tumours to improve diagnosis, treatment and prognosis

Tumours of central nervous system (CNS) origin are the second most prevalent group of cancers in children, yet account for the majority of childhood cancer-related deaths. Such tumours show diverse location, cell type of origin, disease course and long-term outcome, both across and within tumour types, making treatment problematic and contributing to the relatively modest progress in reducing mortality over recent decades. As technological advances begin to reveal the genetic landscape of all cancers, it is becoming increasingly clear that genetic disruption represents only one 'layer' of molecular disruption associated with disease aetiology. Obtaining a full understanding of tumour behaviour requires an understanding of the cellular and molecular pathways disrupted during tumourigenesis, particularly in relation to gene expression. The utility of such an approach has allowed stratification of cancers such as medulloblastoma into subgroups based on molecular features, with potential to refine risk prediction. Given that epigenetic disruption is a universal feature of all human cancers, it is logical to speculate that interrogating epigenetic marks may help to further define the molecular profile, and therefore the clinical trajectory, of tumours. An integrated approach to build a molecular 'signature' of individual tumours that incorporates traditional morphological and demographic information, genetic and transcriptome analysis, in addition to epigenomics (DNA methylation and non-coding RNA analysis), offers tremendous promise to (i) inform treatment approach, (ii) facilitate accurate early identification (preferably at diagnosis) of variable risk groups (both good and poor prognosis groups), and (iii) track disease progression in childhood CNS tumours.

The placental exposome: placental determinants of fetal adiposity and postnatal body composition

Offspring of obese and diabetic mothers are at increased risk of being born with excess adiposity as a consequence of their intrauterine environment. Excessive fetal fat accretion reflects additional placental nutrient transfer, suggesting an effect of the maternal environment on placental function. High plasma levels of particular nutrients in obese and diabetic mothers are likely to be the important drivers of nutrient transfer to the fetus, resulting in excess fat accretion. However, not all offspring of obese and diabetic mothers are born large for gestational age and the explanation may involve the regulation of placental nutrient transfer required for fetal growth. The placenta integrates maternal and fetal signals across gestation in order to determine nutrient transfer rate. Understanding the nature of these signals and placental responses to them is key to understanding the pathology of both fetal growth restriction and macrosomia. The overall effects of the maternal environment on the placenta are the product of its exposures throughout gestation, the 'placental exposome'. Understanding these environmental influences is important as exposures early in gestation, for instance causing changes in the function of genes involved in nutrient transfer, may determine how the placenta will respond to exposures later in gestation, such as to raised maternal plasma glucose or lipid concentrations. Longitudinal studies are required which allow investigation of the influences on the placenta across gestation. These studies need to make full use of developing technologies characterising placental function, fetal growth and body composition. Understanding these processes will assist in the development of preventive strategies and treatments to optimise prenatal growth in those pregnancies at risk of either excess or insufficient nutrient supply and could also reduce the risk of chronic disease in later life.

Decreased cortical muscarinic M1 receptors in schizophrenia are associated with changes in gene promoter methylation, mRNA and gene targeting microRNA

Many studies have shown decreased cortical muscarinic M1 receptors (CHRM1) in schizophrenia (Sz), with one study showing Sz can be separated into two populations based on a marked loss of CHRM1 (-75%) in -25% of people (Def-Sz) with the disorder. To better understand the mechanism contributing to the loss of CHRM1 in Def-Sz, we measured specific markers of gene expression in the cortex of people with Sz as a whole, people differentiated into Def-Sz and people with Sz that do not have a deficit in cortical CHRM1 (Non-Def-Sz) and health controls. We now report that cortical CHRM1 gene promoter methylation and CHRM1 mRNA are decrease in Sz, Def-Sz and Non-Def-Sz but levels of the micro RNA (miR)-107, a CHRM1 targeting miR, are increased only in Def-Sz. We also report in vitro data strongly supporting the notion that miR-107 levels regulate CHRM1 expression. These data suggest there is a reversal of the expected inverse relationship between gene promoter methylation and CHRM1 mRNA in people with Sz and that a breakdown in gene promoter methylation control of CHRM1 expression is contributing to the global pathophysiology of the syndrome. In addition, our data argues that increased levels of at least one miR, miR-107, is contributing to the marked loss of cortical CHRM1 in Def-Sz and this may be a differentiating pathophysiology. These latter data continue to support the hypothesis that microRNAs (miRNA) have a role in the underlying neurobiology of Sz but argue they are differentially affected in subsets of people within that syndrome.

IFPA Meeting 2012 Workshop Report II: epigenetics and imprinting in the placenta, growth factors and villous trophoblast differentiation, role of the placenta in regulating fetal exposure to xenobiotics during pregnancy, infection and the placenta

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, four of which are summarized in this report. These workshops related to various aspects of placental biology: 1) epigenetics and imprinting in the placenta; 2) growth factors and villous trophoblast differentiation; 3) role of the placenta in regulating fetal exposure to xenobiotics during pregnancy; 4) infection and the placenta.

Genome-scale profiling reveals a subset of genes regulated by DNA methylation that program somatic T-cell phenotypes in humans

The aim of this study was to investigate the dynamics and relationship between DNA methylation and gene expression during early T-cell development. Mononuclear cells were collected at birth and at 12 months from 60 infants and were either activated with anti-CD3 for 24 h or cultured in media alone, and the CD4+ T-cell subset purified. DNA and RNA were co-harvested and DNA methylation was measured in 450 000 CpG sites in parallel with expression measurements taken from 25 000 genes. In unstimulated cells, we found that a subset of 1188 differentially methylated loci were associated with a change in expression in 599 genes (adjusted P value<0.01, β-fold >0.1). These genes were enriched in reprogramming regions of the genome known to control pluripotency. In contrast, over 630 genes were induced following low-level T-cell activation, but this was not associated with any significant change in DNA methylation. We conclude that DNA methylation is dynamic during early T-cell development, and has a role in the consolidation of T-cell-specific gene expression. During the early phase of clonal expansion, DNA methylation is stable and therefore appears to be of limited importance in short-term T-cell responsiveness.

IFPA Meeting 2010 Workshops Report II: Placental pathology; trophoblast invasion; fetal sex; parasites and the placenta; decidua and embryonic or fetal loss; trophoblast differentiation and syncytialisation

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications.

IFPA Meeting 2010 Workshop Report I: Immunology; ion transport; epigenetics; vascular reactivity; epitheliochorial placentation; proteomics

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 there were twelve themed workshops, six of which are summarized in this report. 1. The immunology workshop focused on normal and pathological functions of the maternal immune system in pregnancy. 2. The transport workshop dealt with regulation of ion and water transport across the syncytiotrophoblast of human placenta. 3. The epigenetics workshop covered DNA methylation and its potential role in regulating gene expression in placental development and disease. 4. The vascular reactivity workshop concentrated on methodological approaches used to study placental vascular function. 5. The workshop on epitheliochorial placentation covered current advances from in vivo and in vitro studies of different domestic species. 6. The proteomics workshop focused on a variety of techniques and procedures necessary for proteomic analysis and how they may be implemented for placental research.

Wheel running and environmental enrichment differentially modify exon-specific BDNF expression in the hippocampus of wild-type and pre-motor symptomatic male and female Huntington's disease mice

Brain-derived neurotrophic factor (BDNF) is an essential neurotrophin and regulation of its expression is complex due to multiple 5' untranslated exons which are separately spliced to a common coding exon to form unique mRNA transcripts. Disruption of BDNF gene expression is a key to the development of symptoms in Huntington's disease (HD), a fatal neurodegenerative condition. Abnormal epigenetic modifications are associated with reduced gene expression in late-stage HD but such regulation of BDNF gene expression has yet to be investigated. We hypothesized that BDNF gene expression is altered in the HD hippocampus of pre-motor symptomatic R6/1 transgenic HD mice, correlating with a change in the DNA methylation profile. The effects of wheel-running and environmental enrichment on wild-type mice, in association with a proposed environment-mediated correction of BDNF gene expression deficits in HD mice, were also investigated. Using real-time PCR, levels of total BDNF mRNA were found to be reduced in the hippocampus of both male and female HD mice. Wheel-running significantly increased total BDNF gene expression in all groups of mice except male HD mice. In contrast, environmental enrichment significantly increased expression only in male wild-type animals. Further quantification of BDNF exon-specific transcripts revealed sex-specific changes in relation to the effect of the HD mutation and differential effects on gene expression by wheel-running and environmental enrichment. The HD-associated reduction of BDNF gene expression was not due to increased methylation of the gene sequence. Furthermore, environment-induced changes in BDNF gene expression in the wild-type hippocampus were independent of the extent of DNA methylation. Overall, the results of this study provide new insight into the role of BDNF in HD pathogenesis in addition to the mechanisms regulating normal BDNF gene expression.

IFPA Meeting 2009 workshops report

Workshops are an important part of the annual meeting of the International Federation of Placenta Associations (IFPA). At IFPA Meeting 2009 diverse topics were discussed in twelve themed workshops. Topics covered included: immune response to pregnancy; signaling between fetus and placenta; bioactive lipids in placenta; placenta in agricultural species; epigenetics and placentation; trophoblast deportation; glucocorticoids and placental function; endothelium; placental transport; genes and placenta; uteroplacental blood flow and placental stem cells. This report is a full summary of the various topics covered.

Microbial exposure, interferon gamma gene demethylation in naïve T-cells, and the risk of allergic disease

The period of immune programming during early life presents a critical window of opportunity for the prevention of allergic diseases. There is mounting evidence that inappropriate immune programming may involve disruption of specific epigenetic modifications (switches) at immune-related genes. This novel area of research has great potential, as epigenetic changes are known to be sensitive to environmental factors and may therefore provide a mechanistic link for the observed association between specific environmental cues, faulty immune development, and the risk of allergic disease. In addition, the dynamic and potentially reversible nature of epigenetic modifications offers potentially novel targets for therapeutic and/or preventative interventions. We review the evidence that (1) failure to up-regulate the interferon gamma (IFNgamma) response during infancy is an important determinant of the risk of allergic disease, (2) expression of the IFNgamma gene in naïve T-cells is regulated by epigenetic mechanisms, and (3) failure to up-regulate IFNgamma gene expression of naïve T-cells associated with low early life microbial exposure. Taken together, these lines of evidence suggest that low microbial exposure during early life increases the risk of allergic disease by reducing demethylation (activation) of the IFNgamma gene of naive T-cells.

Specific tumour-associated methylation in normal human term placenta and first-trimester cytotrophoblasts

Human placentation displays many similarities with tumourigenesis, including rapid cell division, migration and invasion, overlapping gene expression profiles and escape from immune detection. Recent data have identified promoter methylation in the Ras association factor and adenomatous polyposis coli tumour suppressor genes as part of this process. However, the extent of tumour-associated methylation in the placenta remains unclear. Using whole genome methylation data as a starting point, we have examined this phenomenon in placental tissue. We found no evidence for methylation of the majority of common tumour suppressor genes in term placentas, but identified methylation in several genes previously described in some human tumours. Notably, promoter methylation of four independent negative regulators of Wnt signalling has now been identified in human placental tissue and purified trophoblasts. Methylation is present in baboon, but not in mouse placentas. This supports a role for elevated Wnt signalling in primate trophoblast invasiveness and placentation. Examination of invasive choriocarcinoma cell lines revealed altered methylation patterns consistent with a role of methylation change in gestational trophoblastic disease. This distinct pattern of tumour-associated methylation implicates a coordinated series of epigenetic silencing events, similar to those associated with some tumours, in the distinct features of normal human placental invasion and function.

Construction of neocentromere-based human minichromosomes for gene delivery and centromere studies

Human neocentromeres are fully functional centromeres that arise naturally in non-centromeric regions devoid of alpha-satellite DNA. We have successfully produced a series of minichromosomes by telomere-associated truncation of a marker chromosome mardel(10) containing a neocentromere. The resulting minichromosomes are either linear or circular in nature, and range in size from approximately 650 kb to 2 Mb. These minichromosomes exhibit full centromeric activity, bind to essential centromere proteins, and are mitotically stable over many generations. They provide a useful system for dissecting the functional domains of complex eukaryotic centromeres and as vectors for therapeutic gene delivery.

Mosaic inv dup(8p) marker chromosome with stable neocentromere suggests neocentromerization is a post-zygotic event

Marker chromosomes containing active human neocentromeres have been described in individuals where the chromosomes are non-mosaic, suggesting that they are mitotically stable, but also in individuals where there is mosaicism, raising the possibility of neocentromere instability. We report two independently ascertained individuals who are mosaic for a supernumerary marker chromosome, shown by reverse chromosome painting to have an 8p origin, resulting in mosaicism for tetrasomy 8p23.1-->pter in the patient. The markers have a primary constriction but show no detectable centromeric alpha-satellite DNA. The marker in Patient 1 demonstrated no centromere protein CENP-B binding, but associated with nine different functionally critical centromere proteins. Investigation of peripheral blood lymphocytes from this patient on five separate occasions over a 13-year period showed 23-46% mosaicism for the marker chromosome with no decrease in incidence. In vitro investigation of primary and secondary sub-clones of a lymphoblast cell line derived from the patient demonstrated 100% stability of the marker chromosome indicating that neocentromere instability is unlikely to be responsible for the mosaicism in the patient. This and other available data support a general model of neocentromerization as a post-zygotic event, irrespective of whether the supernumerary chromosome fragment has arisen during meiosis or post-fertilization at mitosis.

Construction of neocentromere-based human minichromosomes by telomere-associated chromosomal truncation

Neocentromeres (NCs) are fully functional centromeres that arise ectopically in noncentromeric regions lacking alpha-satellite DNA. Using telomere-associated chromosome truncation, we have produced a series of minichromosomes (MiCs) from a mardel(10) marker chromosome containing a previously characterized human NC. These MiCs range in size from approximately 0.7 to 1.8 Mb and contain single-copy intact genomic DNA from the 10q25 region. Two of these NC-based Mi-Cs (NC-MiCs) appear circular whereas one is linear. All demonstrate stability in both structure and mitotic transmission in the absence of drug selection. Presence of a functional NC is shown by binding a host of key centromere-associated proteins. These NC-MiCs provide direct evidence for mitotic segregation function of the NC DNA and represent examples of stable mammalian MiCs lacking centromeric repeats.

Components of the human spindle checkpoint control mechanism localize specifically to the active centromere on dicentric chromosomes

The spindle checkpoint control mechanism functions to ensure faithful chromosome segregation by delaying cell division until all chromosomes are correctly oriented on the mitotic spindle. Initially identified in budding yeast, several mammalian spindle checkpoint-associated proteins have recently been identified and partially characterized. These proteins associate with all active human centromeres, including neocentromeres, in the early stages of mitosis prior to the commencement of anaphase. We have examined the status of proteins associated with the checkpoint protein complex (BUB1, BUBR1, BUB3, MAD2), the anaphase-promoting complex (Tsg24, p55CDC), and other proteins associated with mitotic checkpoint control (ERK1, 3F3/2 epitope, hZW10), on a human dicentric chromosome. Each of these proteins was found to specifically associate with only the active centromere, suggesting that only active centromeres participate in the spindle checkpoint. This finding complements previous studies on multicentric chromosomes demonstrating specific association of structural and motor-related centromere proteins with active centromeres, and suggests that centromere inactivation is accompanied by loss of all functionally important centromere proteins.

Genetic mapping of mouse centromere protein (Incenp and Cenpe) genes

Inner centromere protein (INCENP) and centromere protein E (CENPE) are two functionally important proteins of the higher eukaryotic centromere. Using a mouse Incenp genomic DNA and a mouse Cenpe cDNA to analyze recombinant inbred mouse sets, as well as interspecific backcross panels, we have mapped these genes to the proximal regions of mouse Chromosomes 19 and 6, respectively. Comparison of Cenpe and human CENPE, which maps to chromosome region 4q24-->q25, has further identified a new region of homology between the two species.

The 10q25 neocentromere and its inactive progenitor have identical primary nucleotide sequence: further evidence for epigenetic modification

We have previously localized the core centromere protein-binding domain of a 10q25.2-derived neocentromere to an 80-kb genomic region. Detailed analysis has indicated that the 80-kb neocentromere (NC) DNA has a similar overall organization to the corresponding region on a normal chromosome 10 (HC) DNA, derived from a genetically unrelated CEPH individual. Here we report sequencing of the HC DNA and its comparison to the NC sequence. Single-base differences were observed at a maximum rate of 4.6 per kb; however, no deletions, insertions, or other structural rearrangements were detected. To investigate whether the observed changes, or subsets of these, might be de novo mutations involved in neocentromerization (i.e., in committing a region of a chromosome to neocentromere formation), the progenitor DNA (PnC) from which the NC DNA descended, was cloned and sequenced. Direct comparison of the PnC and NC sequences revealed 100% identity, suggesting that the differences between NC and HC DNA are single nucleotide polymorphisms (SNPs) and that formation of the 10q25.2 NC did not involve a change in DNA sequence in the core centromere protein-binding NC region. This is the first study in which a cloned NC DNA has been compared directly with its inactive progenitor DNA at the primary sequence level. The results form the basis for future sequence comparison outside the core protein-binding domain, and provide direct support for the involvement of an epigenetic mechanism in neocentromerization.

HZwint-1, a novel human kinetochore component that interacts with HZW10

HZwint-1 (Human ZW10 interacting protein-1) was identified in a yeast two hybrid screen for proteins that interact with HZW10. HZwint-1 cDNA encodes a 43 kDa protein predicted to contain an extended coiled-coil domain. Immunofluorescence studies with sera raised against HZwint-1 protein revealed strong kinetochore staining in nocodazole-arrested chromosome spreads. This signal co-localizes at the kinetochore with HZW10, at a position slightly outside of the central part of the centromere as revealed by staining with a CREST serum. The kinetochore localization of HZwint-1 has been confirmed by following GFP fluorescence in HeLa cells transiently transfected with a plasmid encoding a GFP/HZwint-1 fusion protein. In cycling HeLa cells, HZwint-1 localizes to the kinetochore of prophase HeLa cells prior to HZW10 localization, and remains at the kinetochore until late in anaphase. This localization pattern, combined with the two-hybrid results, suggests that HZwint-1 may play a role in targeting HZW10 to the kinetochore at prometaphase. HZwint-1 was also found to localize to neocentromeres and to the active centromere of dicentric chromosomes. HZwint-1 thus appears to associate with all active centromeres, implying that it plays an important role in correct centromere function.

Poly(ADP-ribose) polymerase at active centromeres and neocentromeres at metaphase

A double-stranded 9 bp GTGAAAAAG pJ alpha sequence found in human centromeric alpha-satellite DNA and a 28 bp ATGTATATATGTGTATATAGACATAAAT tandemly repeated AT28 sequence found within a cloned neo- centromere DNA have each allowed the affinity purification of a nuclear protein that we have identified as poly(ADP-ribose) polymerase (PARP). Use of other related or unrelated oligonucleotide sequences as affinity substrates has indicated either significantly reduced or no detectable PARP purification, suggesting preferential but not absolute sequence-specific binding. Immunofluorescence analysis of human and sheep metaphase cells using a polyclonal anti-PARP antibody revealed centromeric localization of PARP, with diffuse signals also seen on the chromosome arms. Similar results were observed for mouse chromosomes except for a significantly enlarged PARP-binding region around the core centromere-active domain, suggesting possible 'spreading' of PARP into surrounding non-core centromeric domains. Enhanced PARP signals were also observed on alpha-satellite-negative human neo- centromeres and on the active but not the inactive alpha-satellite-containing centromere of a human dicentric chromosome. PARP signals were absent from the q12 heterochromatin of the Y chromosome, suggesting a correlation of PARP binding with centromere function that is independent of heterochromatic properties. Preliminary cell cycle analysis indicates detectable centromeric association of PARP during S/G(2)phase and that the total proportion of PARP that is centromeric is relatively low. Strong binding of PARP to different centromere sequence motifs may offer a versatile mechanism of mammalian centromere recognition that is independent of primary DNA sequences.

Human centromeres and neocentromeres show identical distribution patterns of >20 functionally important kinetochore-associated proteins

Using combined immunofluorescence and fluorescence in situ hybridization (FISH) analysis we have extensively characterized the proteins associating with two different homologue human neocentromeres at interphase and prometaphase/metaphase, and compared these directly with those found with normal human centromeres. Antisera to CENP-A, CENP-B, CENP-C, CENP-E, CENP-F, INCENP, CLIP-170, dynein, dynactin subunits p150 (Glued) and Arp1, MCAK, Tsg24, p55CDC, HZW10, HBUB1, HBUBR1, BUB3, MAD2, ERK1, 3F3/2, topoisomerase II and a murine HP1 homologue, M31, were used in immuno-fluorescence experiments in conjunction with FISH employing specific DNA probes to clearly identify neocentromeric DNA. We found that except for the total absence of CENP-B binding, neocentromeres are indistinguishable from their alpha satellite-containing counterparts in terms of protein composition and distribution. This suggests that the DNA base of a potential centromeric locus is of minimal importance in determining the overall structure of a functional kinetochore and that, once seeded, the events leading to functional kinetochore formation occur independently of primary DNA sequence.