Gestación tras cáncer / Pregnancy after cancer

El embarazo o el deseo gestacional en personas con antecedentes oncológicos son situaciones clínicas de frecuencia creciente que requieren un abordaje global. El consejo preconcepcional es básico en estos casos, y debe incluir una valoración conjunta y una coordinación multidisciplinar entre los especialistas de oncología o del proceso de base, de fertilidad o reproducción, y obstetricia o medicina maternofetal. El objetivo de esta valoración incluye consensuar el momento óptimo para asumir una gestación de forma segura sin empeorar el pronóstico de su enfermedad y planificar el seguimiento de la gestación de acuerdo con las posibles complicaciones maternas o perinatales. En la presente revisión se detallan los aspectos reproductivos más relevantes de tres de los tipos de cáncer más frecuentes en la edad reproductiva: el cáncer de mama, el cáncer de cérvix y los cánceres hematológicos.(AU)

Pregnancy or reproductive desire in people with a previous cancer represents a clinical situation of increasing frequency that requires a global approach. Preconceptional counseling is mandatory in these cases and should include a global assessment and multidisciplinary coordination between specialists in oncology, fertility and obstetrics or maternal-fetal medicine. The objective of this assessment includes determining the optimal time-to-pregnancy safe for the mother, without worsening the prognosis of the disease and planning the pregnancy follow-up according to possible maternal or perinatal complications. This review details the most relevant reproductive aspects of three of the most frequent types of cancer during reproductive age: breast cancer, cervical cancer and hematological cancers.(AU)

A systematic review of evidence for maternal preconception exposure to outdoor air pollution on Children's health.

The preconception period is a critical window for gametogenesis, therefore preconception exposure to air pollutants may have long-term effects on children. We systematically reviewed epidemiological evidence concerning the effects of preconception ambient air pollution exposure on children's health outcomes and identified research gaps for future investigations. We searched PubMed and Web of Science from journal inception up to October 2022 based on an established protocol (PROSPERO: CRD42022277608). We then identified 162 articles based on searching strategy, 22 of which met the inclusion criteria. Studies covered a wide range of health outcomes including birth defects, preterm birth, birthweight, respiratory outcomes, and developmental outcomes. Findings suggested that exposure to outdoor air pollutants during maternal preconception period were associated with various health outcomes, of which birth defects has the most consistent findings. A meta-analysis revealed that during 3-month preconception period, a 10 µg/m3 increase in PM10 and PM2.5 was associated with relative risk (RR) of birth defects of 1.06 (95% confidence interval (CI): 1.00, 1.02) and 1.14 (95% CI: 0.82, 1.59), respectively. Preterm birth, low birthweight, and autism have also been associated with maternal preconception exposure to PM2.5, PM10, O3 and SO2. However, the significance of associations and effect sizes varied substantially across studies, partly due to the heterogeneity in exposure and outcome assessments. Future studies should use more accurate exposure assessment methods to obtain individual-level exposures with high temporal resolution. This will allow the exploration of which specific time window (weeks or months) during the preconception period has the strongest effect. In future epidemiologic studies, integrating pathophysiologic biomarkers relevant to clinical outcomes may help improve the causal inference of associations between preconception exposure and health outcomes suggested by the current limited literature. Additionally, potential effects of paternal preconception exposure need to be studied.

Prenatal exposure to titanium dioxide nanoparticles induces persistent neurobehavioral impairments in maternal mice that is associated with microbiota-gut-brain axis.

Gestational exposure to titanium dioxide nanoparticles (TiO2NPs) has been widely reported to have deleterious effects on the brain functions of offspring. However, little attention has been paid to the neurotoxic effects of TiO2NPs on maternal body after parturition. The pregnant mice were orally administrated with TiO2NPs at 150 mg/kg from gestational day 8-21. The potential effects of TiO2NPs on the neurobehaviors were evaluated at postnatal day 60. The gut microbiota, morphological alterations of intestine and brain, and other indicators that involved in gut-brain axis were all assessed to investigate the underlying mechanisms. The results demonstrated that exposure to TiO2NPs during pregnancy caused the persistent neurobehavioral impairments of maternal mice after delivery for 60 days, mainly including behavioural changes, pathological changes in hippocampus, cortex and intestine. Our data also showed that persistent dysfunction and tissue injuries were probably associated with the disruption of gut-brain axis, manifested by the shift in the composition of gut microbial community, alteration of Sstr1, inhibition of enteric neurons and reduction of diamine oxidase contents in maternal mice. These findings provide a novel insight that regulation of gut microecology may be an alternative strategy for the protection against the neurotoxicity of TiO2NPs in pregnant women.

Effect of maternal alcohol consumption during the pre-pregnancy/early-pregnancy period on congenital heart disease: A prospective cohort study in Central China.

Evidence of associations between maternal alcohol consumption and congenital heart disease (CHD) are mixed. Previous studies have been potentially biased due to recall bias or unmeasured confounding. This study aimed to examine the association of maternal alcohol consumption in 3 months before pregnancy and in early pregnancy with risks of offspring congenital heart disease (CHD) and its seven common subtypes. A prospective cohort study was conducted in Central China. From 03/13/2013 to 12/31/2019, a total of 44,048 pregnant women with singleton pregnancies at 8-14 gestational weeks were included and followed to 3 months postpartum. 564 births were diagnosed with CHD at the end of follow-up. Multivariable modified Poisson regression models were used to estimate the relative risks (RRs) of CHD in offspring exposed to maternal alcohol consumption during the pre-pregnancy and early-pregnancy period, adjusting for confounders identified by directed acyclic graphs. In the multivariable analyses, increased risks of CHDs were found in offspring exposed to maternal alcohol consumption both in 3 months before pregnancy (adjusted-RR:3.14; 95% confidence intervals[CIs]:2.30-4.28) and in early pregnancy (adjusted-RR:1.86; 95%CIs:1.13-3.05). More specifically, the offspring exposed to maternal alcohol consumption in 3 months before pregnancy had the highest increased risk of Tetralogy of Fallot (adjusted-RR:8.62; 95%CIs:3.61-20.61). These findings persisted in analyses that were further adjusted for the other behavior variables other than the characteristic being assessed, and were also confirmed by sensitivity analyses. Our study supports the need for continued efforts for public health messages surrounding the potential risks of alcohol consumption prior to or during pregnancy.

Maternal preconception occupational exposure to cleaning products and disinfectants and offspring asthma.

BACKGROUND: Emerging research suggests health effects in offspring after parental chemical exposures before conception. Many future mothers are exposed to potent chemicals at work, but potential offspring health effects are hardly investigated. OBJECTIVE: We sought to investigate childhood asthma in relation to mother's occupational exposure to cleaning products and disinfectants before conception. METHODS: The multicenter Respiratory Health In Northern Europe/Respiratory Health In Northern Europe, Spain and Australia generation study investigated asthma and wheeze starting at age less than 10 years in 3318 mother-offspring pairs. From an asthma-specific Job-Exposure Matrix and mothers' occupational history, we defined maternal occupational exposure to indoor cleaning agents (cleaning products/detergents and disinfectants) starting before conception, in the 2-year period around conception and pregnancy, or after birth. Never-employed mothers were excluded. Exposed groups include cleaners, health care workers, cooks, and so forth. Associations were analyzed using mixed-effects logistic regression and ordinary logistic regression with clustered robust SEs and adjustment for maternal education. RESULTS: Maternal occupational exposure to indoor cleaning starting preconception and continuing (n = 610) was associated with offspring's childhood asthma: odds ratio 1.56 (95% CI, 1.05-2.31), childhood asthma with nasal allergies: 1.77 (1.13-2.77), and childhood wheeze and/or asthma: 1.71 (95% CI, 1.19-2.44). Exposure starting around conception and pregnancy (n = 77) was associated with increased childhood wheeze and/or asthma: 2.25 (95% CI, 1.03-4.91). Exposure starting after birth was not associated with asthma outcomes (1.13 [95% CI, 0.71-1.80], 1.15 [95% CI, 0.67-1.97], 1.08 [95% CI, 0.69-1.67]). CONCLUSIONS: Mother's occupational exposure to indoor cleaning agents starting before conception, or around conception and pregnancy, was associated with more childhood asthma and wheeze in offspring. Considering potential implications for vast numbers of women in childbearing age using cleaning agents, and their children, further research is imperative.

Brain and placental transcriptional responses as a readout of maternal and paternal preconception stress are fetal sex specific.

INTRODUCTION: Despite a wealth of epidemiological evidence that cumulative parental lifetime stress experiences prior to conception are determinant of offspring developmental trajectories, there is a lack of insight on how these previous stress experiences are stored and communicated intergenerationally. Preconception experiences may impact offspring development through alterations in transcriptional regulation of the placenta, a major determinant of offspring growth and sex-specific developmental outcomes. We evaluated the lasting influence of maternal and paternal preconception stress (PCS) on the mid-gestation placenta and fetal brain, utilizing their transcriptomes as proximate readouts of intergenerational impact. METHODS: To assess the combined vs. dominant influence of maternal and paternal preconception environment on sex-specific fetal development, we compared transcriptional outcomes using a breeding scheme of one stressed parent, both stressed parents, or no stressed parents as controls. RESULTS: Interestingly, offspring sex affected the directionality of transcriptional changes in response to PCS, where male tissues showed a predominant downregulation, and female tissues showed an upregulation. There was also an intriguing effect of parental sex on placental programming where paternal PCS drove more effects in female placentas, while maternal PCS produced more transcriptional changes in male placentas. However, in the fetal brain, maternal PCS produced overall more changes in gene expression than paternal PCS, supporting the idea that the intrauterine environment may have a larger overall influence on the developing brain than it does on shaping the placenta. DISCUSSION: Preconception experiences drive changes in the placental and the fetal brain transcriptome at a critical developmental timepoint. While not determinant, these altered transcriptional states may underlie sex-biased risk or resilience to stressful experiences later in life.

Associations of Preconception Exposure to Air Pollution and Greenness with Offspring Asthma and Hay Fever.

We investigated if greenness and air pollution exposure in parents' childhood affect offspring asthma and hay fever, and if effects were mediated through parental asthma, pregnancy greenness/pollution exposure, and offspring exposure. We analysed 1106 parents with 1949 offspring (mean age 35 and 6) from the Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) generation study. Mean particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), black carbon (BC), ozone (O3) (µg/m3) and greenness (normalized difference vegetation index (NDVI)) were calculated for parents 0-18 years old and offspring 0-10 years old, and were categorised in tertiles. We performed logistic regression and mediation analyses for two-pollutant models (clustered by family and centre, stratified by parental lines, and adjusted for grandparental asthma and education). Maternal medium PM2.5 and PM10 exposure was associated with higher offspring asthma risk (odds ratio (OR) 2.23, 95%CI 1.32-3.78, OR 2.27, 95%CI 1.36-3.80), and paternal high BC exposure with lower asthma risk (OR 0.31, 95%CI 0.11-0.87). Hay fever risk increased for offspring of fathers with medium O3 exposure (OR 4.15, 95%CI 1.28-13.50) and mothers with high PM10 exposure (OR 2.66, 95%CI 1.19-5.91). The effect of maternal PM10 exposure on offspring asthma was direct, while for hay fever, it was mediated through exposures in pregnancy and offspring's own exposures. Paternal O3 exposure had a direct effect on offspring hay fever. To conclude, parental exposure to air pollution appears to influence the risk of asthma and allergies in future offspring.

Maternal preconception and first trimester exposure to PM10 and the risk of oral clefts in offspring: a population-based, case-control study.

BACKGROUND: Current literature describes limited and controversial evidence on the associations between maternal preconception and first trimester exposure to particulate matter with a diameter ≤10 µm (PM10) and the risk of oral cleft (OC). METHODS: We conducted a case-control study involving 3086 OC cases and 7950 controls, registered in the Maternal and Child Health Certificate Registry in Liaoning Province between 2010 and 2015. PM10 concentrations were obtained from the Environment Protection Bureau. The exposure windows included the 3 months before pregnancy, the first trimester and the individual months. Unconditional logistic regression model was performed to estimate the OR and 95% CI for the association between PM10 exposure and the risk of OC, cleft lip only (CLO), cleft palate only (CPO), and cleft lip and palate (CLP). RESULTS: Maternal PM10 exposure was positively associated with an increased risk for OC during the 3 months preconception (per 10 µg/m3 increment: OR=1.04, 95% CI 1.01 to 1.07; highest vs lowest quartile: OR=1.23, 95% CI 1.04 to 1.45) and the first trimester (per 10 µg/m3 increment: OR=1.05, 95% CI 1.02 to 1.08; highest vs lowest quartile: OR=1.37, 95% CI 1.15 to 1.64). Analyses based on individual months presented similar positive associations, particularly in the second month of pregnancy (OR=1.77, 95% CI 1.51 to 2.09) for highest versus lowest quartile. In the subtype analysis, stronger associations were observed for CLO, whereas there was negligible evidence for CPO and CLP. Sensitivity analyses using propensity score matching generated similar findings. CONCLUSIONS: Our study provides evidence that PM10 exposure during the 3 months preconception and the first trimester increases the risk of OC.

Developmental exposure of California mice to endocrine disrupting chemicals and potential effects on the microbiome-gut-brain axis at adulthood.

Xenoestrogens are chemicals found in plant products, such as genistein (GEN), and in industrial chemicals, e.g., bisphenol A (BPA), present in plastics and other products that are prevalent in the environment. Early exposure to such endocrine disrupting chemicals (EDC) may affect brain development by directly disrupting neural programming and/or through the microbiome-gut-brain axis. To test this hypothesis, California mice (Peromyscus californicus) offspring were exposed through the maternal diet to GEN (250 mg/kg feed weight) or BPA (5 mg/kg feed weight, low dose- LD or 50 mg/kg, upper dose-UD), and dams were placed on these diets two weeks prior to breeding, throughout gestation, and lactation. Various behaviors, gut microbiota, and fecal metabolome were assessed at 90 days of age. The LD but not UD of BPA exposure resulted in individuals spending more time engaging in repetitive behaviors. GEN exposed individuals were more likely to exhibit such behaviors and showed socio-communicative disturbances. BPA and GEN exposed females had increased number of metabolites involved in carbohydrate metabolism and synthesis. Males exposed to BPA or GEN showed alterations in lysine degradation and phenylalanine and tyrosine metabolism. Current findings indicate cause for concern that developmental exposure to BPA or GEN might affect the microbiome-gut-brain axis.

Impact of preconception vaginal microbiota on women's risk of spontaneous preterm birth: protocol for a prospective case-cohort study.

INTRODUCTION: Bacterial vaginosis (BV) and vaginal microbiota disruption during pregnancy are associated with increased risk of spontaneous preterm birth (SPTB), but clinical trials of BV treatment during pregnancy have shown little or no benefit. An alternative hypothesis is that vaginal bacteria present around conception may lead to SPTB by compromising the protective effects of cervical mucus, colonising the endometrial surface before fetal membrane development, and causing low-level inflammation in the decidua, placenta and fetal membranes. This protocol describes a prospective case-cohort study addressing this hypothesis. METHODS AND ANALYSIS: HIV-seronegative Kenyan women with fertility intent are followed from preconception through pregnancy, delivery and early postpartum. Participants provide monthly vaginal specimens during the preconception period for vaginal microbiota assessment. Estimated date of delivery is determined by last menstrual period and first trimester obstetrical ultrasound. After delivery, a swab is collected from between the fetal membranes. Placenta and umbilical cord samples are collected for histopathology. Broad-range 16S rRNA gene PCR and deep sequencing of preconception vaginal specimens will assess species richness and diversity in women with SPTB versus term delivery. Concentrations of key bacterial species will be compared using quantitative PCR (qPCR). Taxon-directed qPCR will also be used to quantify bacteria from fetal membrane samples and evaluate the association between bacterial concentrations and histopathological evidence of inflammation in the fetal membranes, placenta and umbilical cord. ETHICS AND DISSEMINATION: This study was approved by ethics committees at Kenyatta National Hospital and the University of Washington. Results will be disseminated to clinicians at study sites and partner institutions, presented at conferences and published in peer-reviewed journals. The findings of this study could shift the paradigm for thinking about the mechanisms linking vaginal microbiota and prematurity by focusing attention on the preconception vaginal microbiota as a mediator of SPTB.

[Non-caloric sweeteners in women of reproductive age - A consensus document]. / Edulcorantes no calóricos en la mujer en edad reproductiva: documento de consenso.

INTRODUCTION: Non-nutritive sweeteners (NNS) are food additives that have been used as a possible tool to reduce energy and sugar intake. There is a scientific debate around the real benefits of their use. NNS are substances widely evaluated in the scientific literature. Their safety is reviewed by international regulatory health agencies. Health professionals and consumers often lack education and objective information about food additives based on the best scientific evidence. NNS have been used as a substitute for sucrose, especially by people with diabetes mellitus and obesity. However, concerns related to their possible association with preterm birth have been raised, and also with their use during pregnancy and lactation because of the possibility of metabolic or other consequences in both the mother and offspring. This analysis of the evidence in gynecology and obstetrics presents a review of the most commonly asked questions regarding this matter by health professionals and their patients. This document evaluates a diversity of scientific publications under the sieve of evidence-based medicine and the regulatory framework for food additives to elucidate whether the use of NNS in women in these critical stages of pregnancy and breastfeeding represents a potential risk.

INTRODUCCIÓN: Los edulcorantes no calóricos (ENC) son aditivos de alimentos que se utilizan para sustituir azúcares y potencialmente para reducir la ingesta energética. Existe un debate científico en torno a los beneficios reales de su uso. Los ENC son sustancias ampliamente evaluadas en la literatura científica. Su seguridad es revisada por las agencias regulatorias internacionales del campo de la salud. Los profesionales de la salud y los consumidores con frecuencia carecen de educación e información rigurosa, objetiva y sustentada en la evidencia científica y el juicio clínico sobre el uso de aditivos en los alimentos. Los ENC se han empleado como sustitutos de la sacarosa, en especial por las personas con diabetes mellitus y obesidad. Sin embargo, se han planteado inquietudes relacionadas con su posible asociación con el parto pretérmino y con su uso durante el embarazo y la lactancia, ante la posibilidad de consecuencias metabólicas o de otra índole en la madre o en el neonato. Este análisis de la evidencia en ginecología y obstetricia presenta una revisión que intenta responder a preguntas que habitualmente se hacen al respecto los profesionales de la salud y sus pacientes. En este documento se evalúan diversas publicaciones científicas bajo el tamiz de la medicina basada en la evidencia y del marco regulatorio para aditivos de alimentos con el fin dilucidar si el uso de ENC en las mujeres durante las etapas críticas del embarazo y la lactancia supone o no un posible riesgo.

The "First 1,000 Days+" as Key Contributor to the Double Burden of Malnutrition.

Growth from conception through age 2 years, the "First 1,000 days," is important for long-term health of the growing fetus and child and is influenced by several factors including breastfeeding and complementary feeding. Low- and middle-income countries face a complicated array of factors that influence healthy growth, ranging from high food insecurity, poor sanitation, limited prenatal or neonatal care, and high levels of poverty that exacerbate the "vicious cycle" associated with intergenerational promotion of growth retardation. It is now well recognized that the period prior to conception, both maternal and paternal health and diet, play an important role in fetal development, giving rise to the concept of the "First 1,000 Days+". Breastfeeding and complementary feeding practices can be improved through a combination of interventions such as baby-friendly hospitals, regulations for marketing of foods and beverages to children, adequate counseling and support, and sound social and behavior change communication, but continued research is warranted to make such programs more universal and fully effective. Thus, improving the overall understanding of factors that influence growth, such as improved breastfeeding and age-appropriate and adequate complementary feeding, is critical to reducing the global prevalence of the double burden of malnutrition.

Alterations in sperm-inherited noncoding RNAs associate with late-term fetal growth restriction induced by preconception paternal alcohol use.

Using a mouse model, our group recently described an association between chronic paternal alcohol use prior to conception and deficits in offspring growth. Here, we sought to determine the impact of alcohol exposure on male reproductive physiology and the association of sperm-inherited noncoding RNAs with the transmission of the observed growth defects. Alcohol exposure did not appreciably alter male reproductive physiology or fertility. However, chronic alcohol use reproducibly induced late-term fetal growth restriction in the offspring, which correlated with a shift in the proportional ratio of transfer RNA-derived small RNAs to Piwi-interacting RNAs, as well as altered enrichment of microRNAs miR21, miR30, and miR142 in alcohol-exposed sperm. Although our dataset share similarities to prior works examining the impact of paternal stress on offspring phenotype, we were unable to identify any changes in plasma corticosterone, indicating alcohol may alter sperm-inherited noncoding RNAs through distinct mechanisms.

Intergenerational Effects of Alcohol: A Review of Paternal Preconception Ethanol Exposure Studies and Epigenetic Mechanisms in the Male Germline.

While alcohol use disorder (AUD) is a highly heritable psychiatric disease, efforts to elucidate that heritability by examining genetic variation (e.g., single nucleotide polymorphisms) have been insufficient to fully account for familial AUD risk. Perhaps not coincidently, there has been a burgeoning interest in novel nongenomic mechanisms of inheritance (i.e., epigenetics) that are shaped in the male or female germ cells by significant lifetime experiences such as exposure to chronic stress, malnutrition, or drugs of abuse. While many epidemiological and preclinical studies have long pointed to a role for the parental preconception environment in offspring behavior, over the last decade many studies have implicated a causal relationship between the environmentally sensitive sperm epigenome and intergenerational phenotypes. This critical review will detail the heritable effects of alcohol and the potential role for epigenetics.

Preconception Exposure to Fine Particulate Matter Leads to Cardiac Dysfunction in Adult Male Offspring.

Background Particulate matter (particles < 2.5 µm [ PM 2.5]) exposure during the in utero and postnatal developmental periods causes cardiac dysfunction during adulthood. Here, we investigated the potential priming effects of preconception exposure of PM 2.5 on cardiac function in adult offspring. Methods and Results Male and female friend leukemia virus b (FVB) mice were exposed to either filtered air ( FA ) or PM 2.5 at an average concentration of 38.58 µg/m3 for 6 hours/day, 5 days/week for 3 months. Mice were then crossbred into 2 groups: (1)  FA male× FA female (both parents were exposed to FA preconception) and, (2) PM 2.5male× PM 2.5female (both parents were exposed to PM 2.5 preconception). Male offspring were divided: (1) preconception FA (offspring born to FA exposed parents) and, (2) preconception PM 2.5 (offspring born to PM 2.5 exposed parents) and analyzed at 3 months of age. Echocardiography identified increased left ventricular end systolic volume and reduced posterior wall thickness, reduced %fractional shortening and %ejection fraction in preconception PM 2.5 offspring. Cardiomyocytes isolated from preconception PM 2.5 offspring showed reduced %peak shortening, -dL/dT, TPS 90 and slower calcium reuptake (tau). Gene and protein expression revealed modifications in markers of inflammation ( IL -6, IL -15, TNF α, NF қB, CRP , CD 26E, CD 26P, intercellular adhesion molecule 1, and monocyte chemoattractant protein-1) profibrosis (collagen type III alpha 1 chain), oxidative stress ( NOS 2), antioxidants (Nrf2, SOD , catalase), Ca2+ regulatory proteins ( SERCA 2a, p- PLN , NCX ), and epigenetic regulators (Dnmt1, Dnmt3a, Dnmt3b, Sirt1, and Sirt2) in preconception PM 2.5 offspring. Conclusions Preconception exposure to PM 2.5 results in global cardiac dysfunction in adult offspring, suggesting that abnormalities during development are not limited to the prenatal or postnatal periods but can also be determined before conception.

Childhood asthma and smoking exposures before conception-A three-generational cohort study.

BACKGROUND: Some human and animal studies have recently shown that maternal grandmother's smoking during pregnancy increases the risk of asthma in the grandchildren. We have investigated whether sex of the exposed parent and/or grandchild modifies the association between grandmaternal smoking and grandchild asthma. METHODS: We formed a cohort study based on linkage of national registries with prospectively collected data over three generations. Smoking habits in early pregnancy were registered since 1982 and purchases of prescribed medication since 2005. In all, 10 329 children born since 2005 had information on maternal and grandmaternal smoking on both sides and were followed from birth up to 6 years of age. Ages when medication was purchased were used to classify the cohort into never, early transient (0-3 years), early persistent (0-3 and 4-6 years), and late-onset (4-6 years) phenotypes of childhood asthma. RESULTS: Maternal grandmother's smoking was associated with an increased odds of early persistent asthma after adjustment for maternal smoking and other confounders (odds ratio 1.29, 95% confidence interval 1.10-1.51). Grandchild sex did not modify the association. Paternal grandmother's smoking was not associated with any of the asthma phenotypes. CONCLUSION: Maternal but not paternal exposure to nicotine before conception was related to an increased risk of early persistent childhood asthma, but not other asthma phenotypes. Our findings are possibly consistent with a sex-specific mode of epigenetic transfer.

Periconception endogenous and exogenous maternal sex steroid hormones and risk of asthma and allergy in offspring: protocol for a systematic review and meta-analysis.

INTRODUCTION: Pregnancy is associated with several hormonal changes which influence the developing fetus. Variations in maternal endogenous hormones and prepregnancy use of hormonal preparations have been linked to asthma and allergy in the offspring, but findings are inconsistent. We plan to undertake a systematic review to synthesise the evidence on the association between endogenous and exogenous maternal sex hormones and the risk of asthma and allergy in the offspring. METHODS AND ANALYSIS: We will search Medline, Embase, Cochrane Library, Institute of Scientific Information Web of Science, Cumulative Index of Nursing and Allied Health, Scopus, Google Scholar, Allied and Complementary Medicine Database, Global Health, Psychological Information (PsycINFO), Centre for Agriculture and Bioscience (CAB) International and WHO Global Health Library from inception until 2016 to identify relevant studies on the topic. Additional studies will be identified by searching databases of proceedings of international conferences, contacting international experts in the field and searching the references cited in identified studies. We will include analytical epidemiological studies. Two researchers will independently screen identified studies, undertake data extraction and assess risk of bias in eligible studies, while a third reviewer will arbitrate any disagreement. We will use the Effective Public Health Practice Project tool to assess the risk of bias in the studies. We will perform a random-effects meta-analysis to synthesise the evidence. We will use the Grading of Recommendations Assessment, Development and Evaluation approach to rate the strength and quality of the overall evidence with respect to each outcome. ETHICS AND DISSEMINATION: Ethical approval is not required since the study is a systematic review of published literature. Our findings will be reported in a peer-reviewed scientific journal. PROSPERO REGISTRATION NUMBER: CRD42016048324.

Epigenetics of Autism Spectrum Disorder.

Autism spectrum disorder (ASD), one of the most common childhood neurodevelopmental disorders (NDDs), is diagnosed in 1 of every 68 children. ASD is incredibly heterogeneous both clinically and aetiologically. The etiopathogenesis of ASD is known to be complex, including genetic, environmental and epigenetic factors. Normal epigenetic marks modifiable by both genetics and environmental exposures can result in epigenetic alterations that disrupt the regulation of gene expression, negatively impacting biological pathways important for brain development. In this chapter we aim to summarize some of the important literature that supports a role for epigenetics in the underlying molecular mechanism of ASD. We provide evidence from work in genetics, from environmental exposures and finally from more recent studies aimed at directly determining ASD-specific epigenetic patterns, focusing mainly on DNA methylation (DNAm). Finally, we briefly discuss some of the implications of current research on potential epigenetic targets for therapeutics and novel avenues for future work.

Drug Addiction and DNA Modifications.

Drug addiction is a complex disorder which can be influenced by both genetic and environmental factors. Research has shown that epigenetic modifications can translate environmental signals into changes in gene expression, suggesting that epigenetic changes may underlie the causes and possibly treatment of substance use disorders. This chapter will focus on epigenetic modifications to DNA, which include DNA methylation and several recently defined additional DNA epigenetic changes. We will discuss the functions of DNA modifications and methods for detecting them, followed by a description of the research investigating the function and consequences of drug-induced changes in DNA methylation patterns. Understanding these epigenetic changes may provide us translational tools for the diagnosis and treatment of addiction in the future.

Insight from animal models of environmentally driven epigenetic changes in the developing and adult brain.

The efforts of many neuroscientists are directed toward understanding the appreciable plasticity of the brain and behavior. In recent years, epigenetics has become a core of this focus as a prime mechanistic candidate for behavioral modifications. Animal models have been instrumental in advancing our understanding of environmentally driven changes to the epigenome in the developing and adult brain. This review focuses mainly on such discoveries driven by adverse environments along with their associated behavioral outcomes. While much of the evidence discussed focuses on epigenetics within the central nervous system, several peripheral studies in humans who have experienced significant adversity are also highlighted. As we continue to unravel the link between epigenetics and phenotype, discerning the complexity and specificity of epigenetic changes induced by environments is an important step toward understanding optimal development and how to prevent or ameliorate behavioral deficits bred by disruptive environments.