Predicting later-life outcomes of early-life exposures

Chronic effects of clofibric acid in zebrafish (Danio rerio): a multigenerational study

Clofibric acid (CA) is an active metabolite of the blood lipid lowering agent clofibrate, a pharmaceutical designed to work as agonist of peroxisome proliferator-activated receptor alpha (PPARa). It is the most commonly reported fibrate in aquatic environments with low degradation rate and potential environmental persistence. Previous fish exposures showed that CA may impact spermatogenesis, growth and the expression of fat binding protein genes. However, there are limited data on the effects of chronic multigenerational CA exposures. Here, we assessed chronic multigenerational effects of CA exposure using zebrafish (Danio rerio) as a teleost model. Zebrafish were exposed through the diet to CA (1 and 10mg/g) during their whole lifetime. Growth, reproduction-related parameters and embryonic development were assessed in the exposed fish (F1 generation) and their offspring (F2 generation), together with muscle triglyceride content and gonad histology. In order to study the potential underlying mechanisms, the transcription levels of genes coding for enzymes involved in lipid metabolism pathways were determined. The results show that chronic life-cycle exposure to CA induced a significant reduction in growth of F1 generation and lowered triglyceride muscle content (10mg/g group). Also, an impact in male gonad development was observed together with a decrease in the fecundity (10mg/g group) and higher frequency of embryo abnormalities in the offspring of fish exposed to the lowest CA dose. The profile of the target genes was sex- and tissue-dependent. In F1 an up-regulation of male hepatic pparaa, pparb and acox transcript levels was observed, suggesting an activation of the fatty acid metabolism (provided that transcript level change indicates also a protein level change). Interestingly, the F2 generation, raised with control diet, displayed a response pattern different from that observed in F1, showing an increase in weight in the descendants of CA exposed fish, in comparison with control animals, which points to a multigenerational effect.

Considerations for Using Genetic and Epigenetic Information in Occupational Health Risk Assessment and Standard Setting

Risk assessment forms the basis for both occupational health decision-making and the development of occupational exposure limits (OELs). Although genetic and epigenetic data have not been widely used in risk assessment and ultimately, standard setting, it is possible to envision such uses. A growing body of literature demonstrates that genetic and epigenetic factors condition biological responses to occupational and environmental hazards or serve as targets of them. This presentation addresses the considerations for using genetic and epigenetic information in risk assessments, provides guidance on using this information within the classic risk assessment paradigm, and describes a framework to organize thinking about such uses. The framework is a 4 × 4 matrix involving the risk assessment functions (hazard identification, dose-response modeling, exposure assessment, and risk characterization) on one axis and inherited and acquired genetic and epigenetic data on the other axis. The cells in the matrix identify how genetic and epigenetic data can be used for each risk assessment function. Generally, genetic and epigenetic data might be used as endpoints in hazard identification, as indicators of exposure, as effect modifiers in exposure assessment and dose-response modeling, as descriptors of mode of action, and to characterize toxicity pathways. Vast amounts of genetic and epigenetic data may be generated by high-throughput technologies. These data can be useful for assessing variability and reducing uncertainty in extrapolations, and they may serve as the foundation upon which identification of biological perturbations would lead to a new paradigm of toxicity pathway-based risk assessments.

Considerations for Using Genetic and Epigenetic Information in Occupational Health Risk Assessment and Standard Setting

Risk assessment forms the basis for both occupational health decision-making and the development of occupational exposure limits (OELs). Although genetic and epigenetic data have not been widely used in risk assessment and ultimately, standard setting, it is possible to envision such uses. A growing body of literature demonstrates that genetic and epigenetic factors condition biological responses to occupational and environmental hazards or serve as targets of them. This presentation addresses the considerations for using genetic and epigenetic information in risk assessments, provides guidance on using this information within the classic risk assessment paradigm, and describes a framework to organize thinking about such uses. The framework is a 4 × 4 matrix involving the risk assessment functions (hazard identification, dose-response modeling, exposure assessment, and risk characterization) on one axis and inherited and acquired genetic and epigenetic data on the other axis. The cells in the matrix identify how genetic and epigenetic data can be used for each risk assessment function. Generally, genetic and epigenetic data might be used as endpoints in hazard identification, as indicators of exposure, as effect modifiers in exposure assessment and dose-response modeling, as descriptors of mode of action, and to characterize toxicity pathways. Vast amounts of genetic and epigenetic data may be generated by high-throughput technologies. These data can be useful for assessing variability and reducing uncertainty in extrapolations, and they may serve as the foundation upon which identification of biological perturbations would lead to a new paradigm of toxicity pathway-based risk assessments.

Postnatal weight growth and trihalomethane exposure during pregnancy

BACKGROUND

Impaired postnatal growth after chloroform exposure in utero has been observed in rodents without an effect on birth weight. We aimed to study the relationship between exposure to trihalomethanes (THMs) during pregnancy and postnatal weight growth during infancy.

METHODS

We analysed 2216 mother-child pairs recruited in Gipuzkoa, Sabadell, Valencia (Spain, INMA Project, enrollment: 2003-2008) and Crete (Greece, RHEA Study, enrollment: 2007-2008). Drinking water habits and water-related activities ascertained through personal interviews were combined with THM measurements in drinking water to estimate THM exposure through different exposure routes during pregnancy. Weight measurements during the first year of life were used to fit postnatal weight growth curves from birth to one year and to predict weight at six months. Multiple linear regression was used to evaluate the relationship between six months weight gain and interquartile range (IQR) increase in THM exposure adjusting for confounders.

RESULTS

Average weight gain at six months ranged from 4325 g (Gipuzkoa) to 4668 g (Crete). Median residential THM levels ranged from 1 μg/l (Crete) to 117 μg/l (Sabadell). No significant association was observed overall (-24.4 g [95% CI -78.8, 30.0] for an IQR increase in total residential uptake). A negative relationship was observed in Sabadell (-148 g [95% CI -282, -13.7]) for an IQR increase in ingestion THM uptake.

CONCLUSIONS

No consistent evidence of an association between THM exposure during pregnancy and postnatal growth was observed. The novelty of the hypothesis and the negative trend observed in the region with the highest levels warrants the replication in future studies.

Availability of arsenic in human milk in women and its correlation with arsenic in urine of breastfed children living in arsenic contaminated areas in Bangladesh

BACKGROUND

Early life exposure to inorganic arsenic may be related to adverse health effects in later life. However, there are few data on postnatal arsenic exposure via human milk. In this study, we aimed to determine arsenic levels in human milk and the correlation between arsenic in human milk and arsenic in mothers and infants urine.

METHODS

Between March 2011 and March 2012, this prospective study identified a total of 120 new mother-baby pairs from Kashiani (subdistrict), Bangladesh. Of these, 30 mothers were randomly selected for human milk samples at 1, 6 and 9 months post-natally; the same mother baby pairs were selected for urine sampling at 1 and 6 months. Twelve urine samples from these 30 mother baby pairs were randomly selected for arsenic speciation.

RESULTS

Arsenic concentration in human milk was low and non-normally distributed. The median arsenic concentration in human milk at all three time points remained at 0.5 μg/L. In the mixed model estimates, arsenic concentration in human milk was non-significantly reduced by -0.035 μg/L (95% CI: -0.09 to 0.02) between 1 and 6 months and between 6 and 9 months. With the progression of time, arsenic concentration in infant's urine increased non-significantly by 0.13 μg/L (95% CI: -1.27 to 1.53). Arsenic in human milk at 1 and 6 months was not correlated with arsenic in the infant's urine at the same time points (r = -0.13 at 1 month and r = -0.09 at 6 month). Arsenite (AsIII), arsenate (AsV), monomethyl arsonic acid (MMA), dimethyl arsinic acid (DMA) and arsenobetaine (AsB) were the constituents of total urinary arsenic; DMA was the predominant arsenic metabolite in infant urine.

CONCLUSIONS

We observed a low arsenic concentration in human milk. The concentration was lower than the World Health Organization's maximum permissible limit (WHO Permissible Limit 15 μg/kg-bw/week). Our findings support the safety of breastfeeding even in arsenic contaminated areas.

Effects of developmental activation of the AhR on CD4+ T-cell responses to influenza virus infection in adult mice

BACKGROUND

Epidemiological and animal studies indicate that maternal exposure to pollutants that bind the aryl hydrocarbon receptor (AhR) correlates with poorer ability to combat respiratory infection and lower antibody levels in the offspring. These observations point to an impact on CD4+ T cells. Yet, the consequence of developmental exposure to AhR ligands on the activation and differentiation of CD4+ T cells has not been directly examined.

OBJECTIVES

Our goal was to determine whether maternal exposure to an AhR ligand directly alters CD4+ T cell differentiation and function later in life.

METHODS

C57BL/6 mice were exposed to a prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in utero and via suckling. We then measured CD4+ T-cell activation and differentiation into distinct effector populations in adult offspring that were infected with influenza A virus (IAV). Reciprocal adoptive transfers were used to define whether modifications in CD4+ T-cell responses resulted from direct effects of developmental TCDD exposure on CD4+ T cells.

RESULTS

Developmental exposure skewed CD4+ T-cell responses to IAV infection. We observed fewer virus-specific, activated CD4+ T cells and a reduced frequency of conventional CD4+ effector-cell subsets. However, there was an increase in regulatory CD4+ T cells. Direct effects of AhR activation on CD4+ T cells resulted in impaired differentiation into conventional effector subsets; this defect was transferred to mice that had not been developmentally exposed to TCDD.

CONCLUSIONS

Maternal exposure to TCDD resulted in durable changes in the responsive capacity and differentiation of CD4+ T cells in adult C57BL/6 mice.

Concurrent fetal exposure to multiple environmental chemicals along the U.S.-Mexico border: an exploratory study in Brownsville, Texas

There is mounting concern that cumulative exposure to diverse chemicals in the environment may contribute to observed adverse health outcomes in the Lower Rio Grande Valley of Texas. To investigate this situation, biomarker concentrations of organochlorine (OC) pesticides/metabolites, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were measured in maternal and umbilical cord blood from pregnant Hispanic women in Brownsville, TX. Results show that both mothers and fetuses were exposed concurrently to a variety of relatively low-level, hazardous environmental chemicals. Approximately 10% of the blood specimens had comparatively high concentrations of specific OC pesticides, PCBs and PAHs. Because many pregnant women in Brownsville live in socioeconomically-disadvantaged and environmentally-challenging circumstances, there is appropriate concern that exposure to these exogenous substances, either individually or in combination, may contribute to endemic health problems in this population, including cardiovascular disease, obesity, and diabetes.  The challenge is to identify individuals at highest comparative risk and then implement effective programs to either prevent or reduce cumulative exposures that pose significant health-related threats.

Chlorinated persistent organic pollutants, obesity, and type 2 diabetes

Persistent organic pollutants (POPs) are lipophilic compounds that travel with lipids and accumulate mainly in adipose tissue. Recent human evidence links low-dose POPs to an increased risk of type 2 diabetes (T2D). Because humans are contaminated by POP mixtures and POPs possibly have nonmonotonic dose-response relations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, background exposure to POP mixtures-including organochlorine pesticides and polychlorinated biphenyls-can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to distributional differences in POP mixtures among populations. Differences in the observed shape of the dose-response curves among human studies may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low-dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity, and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans.

Gestational weight gain and exposure of newborns to persistent organic pollutants

BACKGROUND

Exposure to persistent organic pollutants (POPs) during fetal development can increase the risk of adverse health effects during childhood. Maternal characteristics and physiological changes during gestation, such as gestational weight gain (GWG), may have an influence in the overall burden of POPs in neonates. However, the associations between GWG and POP concentrations are still not well established.

OBJECTIVE

We examined the association of GWG with cord serum POPs concentrations after adjusting for prepregnancy maternal body mass index (BMI) and other potential determinants of the transfer of POPs into newborns. The GWG values were evaluated after grouping by the reference guidelines of the Institute of Medicine (IOM).

METHODS

We measured levels of 14 organochlorine pesticides, 7 polychlorobiphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) in 325 cord serum samples from a Spanish birth cohort. Multivariable models were used to estimate associations of GWG, prepregnancy BMI, and other maternal determinants on cord serum concentrations of POPs.

RESULTS

Neonatal concentrations of POPs were inversely associated with GWG after adjustment for age, prepregnancy BMI, educational level, and fish consumption. On average, neonates of women with IOM-recommended GWG have lower POP concentrations than do neonates of mothers with inadequate GWG.

CONCLUSIONS

The present findings suggest an association between neonatal exposure to POPs and inadequate GWG during pregnancy. Encouraging pregnant women to meet the recommended IOM guidelines for GWG may reduce the accumulation of POPs in newborns.

Chlorinated persistent organic pollutants, obesity, and type 2 diabetes

Persistent organic pollutants (POPs) are lipophilic compounds that travel with lipids and accumulate mainly in adipose tissue. Recent human evidence links low-dose POPs to an increased risk of type 2 diabetes (T2D). Because humans are contaminated by POP mixtures and POPs possibly have nonmonotonic dose-response relations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, background exposure to POP mixtures-including organochlorine pesticides and polychlorinated biphenyls-can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to distributional differences in POP mixtures among populations. Differences in the observed shape of the dose-response curves among human studies may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low-dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity, and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans.

Variation of DNA methylation in candidate age-related targets on the mitochondrial-telomere axis in cord blood and placenta

BACKGROUND

Epigenetics is tissue-specific and potentially even cell-specific, but little information is available from human reproductive studies about the concordance of DNA methylation patterns in cord blood and placenta, as well as within-placenta variations. We evaluated methylation levels at promoter regions of candidate genes in biological ageing pathways (SIRT1, TP53, PPARG, PPARGC1A, and TFAM), a subtelomeric region (D4Z4) and the mitochondrial genome (MT-RNR1, D-loop).

METHODS

Ninety individuals were randomly chosen from the ENVIRONAGE birth cohort to evaluate methylation concordance between cord blood and placenta using highly quantitative bisulfite-PCR pyrosequencing. In a subset of nineteen individuals, a more extensive sampling scheme was performed to examine within-placenta variation.

RESULTS

The DNA methylation levels of the subtelomeric region and mitochondrial genome showed concordance between cord blood and placenta with correlation coefficients ranging from r = 0.31 to 0.43, p ≤ 0.005, and also between the maternal and foetal sides of placental tissue (r = 0.53 to 0.72, p ≤ 0.05). For the majority of targets, an agreement in methylation levels between four foetal biopsies was found (with intra-class correlation coefficients ranging from 0.16 to 0.72), indicating small within-placenta variation.

CONCLUSIONS

The methylation levels of the subtelomeric region (D4Z4) and mitochondrial genome (MT-RNR1, D-loop) showed concordance between cord blood and placenta, suggesting a common epigenetic signature of these targets between tissues. Concordance was lacking between the other genes that were studied. In placental tissue, methylation patterns of most targets on the mitochondrial-telomere axis were not strongly influenced by sample location.

Early-life exposure to a herbicide has enduring effects on pathogen-induced mortality

Exposure to stressors at formative stages in the development of wildlife and humans can have enduring effects on health. Understanding which, when and how stressors cause enduring health effects is crucial because these stressors might then be avoided or mitigated during formative stages to prevent lasting increases in disease susceptibility. Nevertheless, the impact of early-life exposure to stressors on the ability of hosts to resist and tolerate infections has yet to be thoroughly investigated. Here, we show that early-life, 6-day exposure to the herbicide atrazine (mean ± s.e.: 65.9±3.48 µg l(-1)) increased frog mortality 46 days after atrazine exposure (post-metamorphosis), but only when frogs were challenged with a chytrid fungus implicated in global amphibian declines. Previous atrazine exposure did not affect resistance of infection (fungal load). Rather, early-life exposure to atrazine altered growth and development, which resulted in exposure to chytrid at more susceptible developmental stages and sizes, and reduced tolerance of infection, elevating mortality risk at an equivalent fungal burden to frogs unexposed to atrazine. Moreover, there was no evidence of recovery from atrazine exposure. Hence, reducing early-life exposure of amphibians to atrazine could reduce lasting increases in the risk of mortality from a disease associated with worldwide amphibian declines. More generally, these findings highlight that a better understanding of how stressors cause enduring effects on disease susceptibility could facilitate disease prevention in wildlife and humans, an approach that is often more cost-effective and efficient than reactive medicine.

Transport of persistent organic pollutants across the human placenta

Prenatal life is the most sensitive stage of human development to environmental pollutants. Early exposure to persistent organic pollutants (POPs) may increase the risk of adverse health effects during childhood. The mechanisms of transference of POPs during pregnancy are still not well understood. The present study is aimed to investigate the transfer of POPs between mother and fetus. The concentrations of 14 organochlorine pesticides, 7 polychlorinated biphenyls (PCBs) and 14 polybromodiphenyl ether (PBDEs) congeners have been measured in 308 maternal serum samples, their respective umbilical cords and 50 placental tissues from a mother-infant cohort representative of Spanish general population. In general, the adjusted lipid-basis concentrations were higher in maternal serum than in cord serum and placenta. The concentrations of most pollutants between maternal serum and cord serum and between maternal serum and placenta were significantly correlated. These distributions were consistent with a predominant maternal source that transfers the pollutants into the placenta and the fetus. However, this distribution did not correspond to passive diffusion of these compounds between these tissues according to lipid content. The compounds more readily metabolized were higher in newborns, which suggest that differences in metabolic capabilities may be responsible of the observed variations in POP distributions between mother and newborns. Prenatal exposure to 4,4'-DDT and some PBDEs such as BDE 99 and BDE 209 is much higher than it could be anticipated from the composition of maternal serum. POP exposure assessment studies of newborns may overlook the effects of some of these pollutants if they only consider maternal determinations.

Exposure to toxic environmental agents

Reducing exposure to toxic environmental agents is a critical area of intervention for obstetricians, gynecologists, and other reproductive health care professionals. Patient exposure to toxic environmental chemicals and other stressors is ubiquitous, and preconception and prenatal exposure to toxic environmental agents can have a profound and lasting effect on reproductive health across the life course.Prenatal exposure to certain chemicals has been documented to increase the risk of cancer in childhood; adult male exposure to pesticides is linked to altered semen quality, sterility, and prostate cancer; and postnatal exposure to some pesticides can interfere with all developmental stages of reproductive function in adult females, including puberty, menstruation and ovulation, fertility and fecundity, and menopause. Many environmental factors harmful to reproductive health disproportionately affect vulnerable and underserved populations,which leaves some populations, including underserved women, more vulnerable to adverse reproductive health effects than other populations. The evidence that links exposure to toxic environmental agents and adverse reproductive and developmental health outcomes is sufficiently robust, and the American College of Obstetricians and Gynecologists and the American Society for Reproductive Medicine join leading scientists and other clinical practitioners in calling for timely action to identify and reduce exposure to toxic environmental agents while addressing the consequences of such exposure.

Long-term low-dose exposure of human urothelial cells to sodium arsenite activates lipocalin-2 via promoter hypomethylation

We previously reported that the sustained exposure of human urothelial cells (HUCs) to low-dose sodium arsenite induces changes in the gene expression profile and neoplastic transformation. In this study, we used the HumanMethylation27 BeadChip to analyze genome-wide methylation profiles and 5-aza-2'-deoxycytidine to examine the involvement of promoter methylation in gene expression. Because the expression of lipocalin-2 (LCN2) was highly enhanced by promoter hypomethylation in inorganic arsenic (iAs)-HUCs cells as well as bladder cancer tissues, we further showed that mutations at the binding sequences for NF-κB and C/EBP-α significantly reduced LCN2 promoter activity. By chromatin immunoprecipitation assay, we demonstrated the significantly increased binding of RelA (p65) and NF-κB1 (p50) to the hypomethylated promoter of LCN2 in the iAs-HUCs. Furthermore, we also demonstrated that LCN2 overexpression was crucial for the neoplastic characteristics of the iAs-HUCs, such as enhanced anchorage-independent growth, resistance to serum deprivation and activation of NF-κB signaling. In addition, our results indicated that enhanced NF-κB activity in iAs-HUCs was via LCN2-mediated increase in intracellular iron and reactive oxygen species levels. Taken together, our results show that sustained low-dose arsenic exposure results in epigenetic changes and enhanced oncogenic potential via LCN2 overexpression.

High arsenic in rice is associated with elevated genotoxic effects in humans

Arsenic in drinking water may cause major deleterious health impacts including death. Although arsenic in rice has recently been demonstrated to be a potential exposure route for humans, there has been to date no direct evidence for the impact of such exposure on human health. Here we show for the first time, through a cohort study in West Bengal, India, involving over 400 human subjects not otherwise significantly exposed to arsenic through drinking water, elevated genotoxic effects, as measured by micronuclei (MN) in urothelial cells, associated with the staple consumption of cooked rice with >200 μg/kg arsenic. Further work is required to determine the applicability to populations with different dietary and genetic characteristics, but with over 3 billion people in the world consuming rice as a staple food and several percent of this rice containing such elevated arsenic concentrations, this study raises considerable concerns over the threat to human health.

Maternal nicotinamide supplementation causes global DNA hypomethylation, uracil hypo-incorporation and gene expression changes in fetal rats

Recent evidence shows that excess nicotinamide can cause epigenetic changes in developing rats. The aim of the present study was to investigate the effects of maternal nicotinamide supplementation on the fetus. Female rats were randomised into four groups fed a standard chow diet (control group) or diets supplemented with 1 g/kg of nicotinamide (low-dose group), 4 g/kg of nicotinamide (high-dose group) or 4 g/kg of nicotinamide plus 2 g/kg of betaine (betaine group) for 14-16 d before mating and throughout the study. Fetal tissue samples were collected on the 20th day of pregnancy. Compared with the control group, the high-dose group had a higher fetal death rate, and the average fetal body weight was higher in the low-dose group but lower in the high-dose group. Nicotinamide supplementation led to a decrease in placental and fetal hepatic genomic DNA methylation and genomic uracil contents (a factor modifying DNA for diversity) in the placenta and fetal liver and brain, which could be completely or partially prevented by betaine. Moreover, nicotinamide supplementation induced tissue-specific alterations in the mRNA expression of the genes encoding nicotinamide N-methyltransferase, DNA methyltransferase 1, catalase and tumour protein p53 in the placenta and fetal liver. High-dose nicotinamide supplementation increased fetal hepatic α-fetoprotein mRNA level, which was prevented by betaine supplementation. It is concluded that maternal nicotinamide supplementation can induce changes in fetal epigenetic modification and DNA base composition. The present study raises the concern that maternal nicotinamide supplementation may play a role in the development of epigenetic-related diseases in the offspring.

Neonatal tumours

Neonatal or perinatal tumours frequently relate to prenatal or developmental events and have a short exposure window which provides an opportunity to study tumours in a selective sensitive period of development. As a result, they display a number of host-specific features which include occasional spontaneous maturational changes with cells still responding to developmental influences. Neonatal tumours (NNT) are studied for a number of important reasons. Firstly, many of the benign tumours arising from soft tissue appear to result from disturbances in growth and development and some are associated with other congenital anomalies. Study of these aspects may open the door for investigation of genetic and epigenetic changes in genes controlling foetal development as well as environmental and drug effects during pregnancy. Secondly, the clinical behaviour of NNT differs from that of similar tumours occurring later in childhood. In addition, certain apparently malignant NNT can 'change course' in infancy leading to the maturation of apparently highly malignant tumours. Thirdly, NNT underline the genetic associations of most tumours but appear to differ in the effects of proto-oncogenes and other oncogenic factors. In this context, there are also connections between the foetal and neonatal period and some "adult" cancers. Fourthly, they appear to arise in a period in which minimal environmental interference has occurred, thus providing a unique potential window of opportunity to study the pathogenesis of tumour behaviour. This study will seek to review what is currently known in each of these areas of study as they apply to NNT. Further study of the provocative differences in tumour behaviour in neonates provides insights into the natural history of cancer in humans and promotes novel cancer therapies.

Exposure to toxic environmental agents

: Reducing exposure to toxic environmental agents is a critical area of intervention for obstetricians, gynecologists, and other reproductive health care professionals. Patient exposure to toxic environmental chemicals and other stressors is ubiquitous, and preconception and prenatal exposure to toxic environmental agents can have a profound and lasting effect on reproductive health across the life course. Prenatal exposure to certain chemicals has been documented to increase the risk of cancer in childhood; adult male exposure to pesticides is linked to altered semen quality, sterility, and prostate cancer; and postnatal exposure to some pesticides can interfere with all developmental stages of reproductive function in adult females, including puberty, menstruation and ovulation, fertility and fecundity, and menopause. Many environmental factors harmful to reproductive health disproportionately affect vulnerable and underserved populations, which leaves some populations, including underserved women, more vulnerable to adverse reproductive health effects than other populations. The evidence that links exposure to toxic environmental agents and adverse reproductive and developmental health outcomes is sufficiently robust, and the American College of Obstetricians and Gynecologists and the American Society for Reproductive Medicine join leading scientists and other clinical practitioners in calling for timely action to identify and reduce exposure to toxic environmental agents while addressing the consequences of such exposure.

Prenatal exposure to environmental contaminants and behavioural problems at age 7-8years

Animal studies showed that the developing brain is particularly sensitive to chemical exposure. Human studies carried out in areas with high exposures have proven neurodevelopmental disorders in relation to e.g. lead and PCBs. Whether these chemicals are associated with behavioural problems in childhood at current environmental levels is not well known. Therefore, we assessed the association between prenatal exposure to lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE and behavioural problems in 7-8year old children. Prenatal exposure data were obtained from the Flemish mother-new-born cohort. Lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE were analysed in cord blood. When the child reached 7-8years, 270 mothers completed the Strengths and Difficulties Questionnaire assessing their children's behavioural health. We found that doubling the prenatal lead exposure (cord blood lead levels) was associated with a 3.43 times higher risk for hyperactivity in both boys and girls. In addition, total difficulties were 5.08 times more likely in the highest tertile for prenatal lead exposure compared to the lowest tertile. In girls, total difficulties were 4.92 more likely when doubling cord blood p,p'-DDE, whereas no significant association was found in boys. Further, we noted in boys a 1.53 times higher risk for emotional problems when doubling cord blood cadmium, whereas no significant association was found in girls. These results indicate that the presence of environmental contaminants influences the mental health of the next generation.

[Developmental origins of adult health and disease: an important concept for social inequalities in health]

According to the theory of the developmental origins of adult health and disease, development in utero and in the first years of life are critical phases during which susceptibility to many chronic diseases is set. Diseases eventually occur only if the environment and lifestyle in later life is favorable. Exposure to chemicals (environmental or drug), to infectious agents, unbalanced nutrition, or psychosocial stress prenatally or in the first months/years of life are all factors which have been shown to impact long-term health of individuals. The consequences, however, are not limited to health. A demonstrative example was provided by the study of the influenza epidemic of 1918-1919 in the United States. Nationwide, it was estimated that the loss of income over a lifetime for individuals exposed during fetal life to this epidemic amounted to 14 billion dollars. This example demonstrates that an exposure during fetal life, which is not socially differentiated, may affect the social situation of individuals in adulthood. In many situations, it is much more difficult to separate the specific effect of a given exposure from the overall effect of the social environment. Indeed, it has been shown that socioeconomic status in childhood is associated with increased risk of mortality in adulthood, even after accounting for the socioeconomic status and risky behaviors in adulthood. Among the explanations, the theory of developmental origins of health credits of biological plausibility the model of critical periods early in which the individual is particularly vulnerable to certain exposures. Thus, ensuring the best conditions for the biological, physical, emotional and cognitive development of children in early life will enable them to reach their potential in terms of health and socioeconomic return to society. Investment in this period also brings the hope of reducing the perpetuation of social inequalities and health from generation to generation.

Obesogens and obesity--an alternative view?

It is accepted that diet is a major contributor to the obesity epidemic, but environmental 'obesogenic' chemicals have also been suggested recently as playing a role, based on in vitro, animal and epidemiological studies. Using two such 'obesogen' examples (bisphenol A, certain phthalate esters), we argue that their association with obesity and obesity-related disorders in humans could be circumstantial, and thus non-causal, because a Western style diet increases exposure to these compounds. This possibility needs to be addressed before further (confounded) epidemiological studies on 'obesogens' are undertaken.

From passive overeating to "food addiction": a spectrum of compulsion and severity

A psychobiological dimension of eating behaviour is proposed, which is anchored at the low end by energy intake that is relatively well matched to energy output and is reflected by a stable body mass index (BMI) in the healthy range. Further along the continuum are increasing degrees of overeating (and BMI) characterized by more severe and more compulsive ingestive behaviours. In light of the many similarities between chronic binge eating and drug abuse, several authorities have adopted the perspective that an apparent dependence on highly palatable food-accompanied by emotional and social distress-can be best conceptualized as an addiction disorder. Therefore, this review also considers the overlapping symptoms and characteristics of binge eating disorder (BED) and models of food addiction, both in preclinical animal studies and in human research. It also presents this work in the context of the modern and "toxic" food environment and therein the ubiquitous triggers for over-consumption. We complete the review by providing evidence that what we have come to call "food addiction" may simply be a more acute and pathologically dense form of BED.

Importance of epigenetic changes in cancer etiology, pathogenesis, clinical profiling, and treatment: what can be learned from hematologic malignancies?

Epigenetic alterations represent a key cancer hallmark, even in hematologic malignancies (HMs) or blood cancers, whose clinical features display a high inter-individual variability. Evidence accumulated in recent years indicates that inactivating DNA hypermethylation preferentially targets the subset of polycomb group (PcG) genes that are regulators of developmental processes. Conversely, activating DNA hypomethylation targets oncogenic signaling pathway genes, but outcomes of both events lead in the overexpression of oncogenic signaling pathways that contribute to the stem-like state of cancer cells. On the basis of recent evidence from population-based, clinical and experimental studies, we hypothesize that factors associated with risk for developing a HM, such as metabolic syndrome and chronic inflammation, trigger epigenetic mechanisms to increase the transcriptional expression of oncogenes and activate oncogenic signaling pathways. Among others, signaling pathways associated with such risk factors include pro-inflammatory nuclear factor κB (NF-κB), and mitogenic, growth, and survival Janus kinase (JAK) intracellular non-receptor tyrosine kinase-triggered pathways, which include signaling pathways such as transducer and activator of transcription (STAT), Ras GTPases/mitogen-activated protein kinases (MAPKs)/extracellular signal-related kinases (ERKs), phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and β-catenin pathways. Recent findings on epigenetic mechanisms at work in HMs and their importance in the etiology and pathogenesis of these diseases are herein summarized and discussed. Furthermore, the role of epigenetic processes in the determination of biological identity, the consequences for interindividual variability in disease clinical profile, and the potential of epigenetic drugs in HMs are also considered.