Dr. Frederica Perera touches on how the environment around us can make a big impact very early in life and stick with us for a long time. This short take was shot during a break at Keystone Symposia’s meeting on Environmental Epigenomics and Disease Susceptibility held in March 2011 in Asheville, North Carolina.
Environmental Exposures and Epigenetics
My field of research is children’s environmental health, and epigenetics plays a potentially very important role in determining the effects of early-life exposures on children’s health and development. So for example, we’re looking at the effects of environmental exposures, physical toxicants in the environment, common every day pollutants that we experience particularly in urban areas (air pollutants, Bisphenol A, phthalates, pesticides) at the low levels to which we’re generally exposed, and we have observed some relationships between fetal exposures (prenatal exposures) and health effects in children following a cohort of children for a number of years from in utero forward into childhood and even adolescence.
So we look upon epigenetics as a potentially very important in mechanism in mediating those effects and in linking, helping us to link exposures to the clinical outcomes that we’re measuring, and in doing so, elucidate the mechanisms by which this damage is incurring, which we hope very much will be useful in prevention in designing effective interventions and also in monitoring the efficacy of those interventions. We’re specifically hypothesizing that prenatal exposure to environmental contaminants polycyclic aromatic hydrocarbons from fossil fuel burning, other combustion sources, secondhand tobacco smoke, pesticides used for control of indoor pests in urban areas, and what are called “endocrine-disrupting” chemicals (Bisphenol A and phthalates) that they are having an effect.
“We theorize that we will be able to draw better links between those early exposures and the outcomes by understanding and measuring the epigenetic changes…”
When the fetus is exposed through the mother’s environmental exposure, that they are having an effect on children’s neurodevelopment, neurobehavior particularly, on asthma risk, and obesity and metabolic disorders, and further, that they may be increasing the risk of intermediate damage associated with cancer. So we further theorized that in addition to genotoxic pathways that can be important for some of these chemical exposures, pollutant exposures, that epigenetics may be involved. And we’re studying that both within our cohorts of mothers and newborns, who are enrolled during the pregnancy period and then followed for many years into adolescence. Our oldest children are now approaching the age of 12 and 13.
We theorize that we will be able to draw better links between those early exposures and the outcomes by understanding and measuring the epigenetic changes both that we determine in the cord blood at birth, looking also at placental tissue and then further following and analyzing the samples from those children at older ages. So we further theorize that the prenatal period would be a window of exquisite susceptibility to these exposures. So those are our hypotheses.
We’re not leaving out, however, the broader context, the social context in which individuals are living, to which they’re reacting on a daily basis. So we are looking at psycho-social stressors, also genetic susceptibility because we think there’s important interaction between genetic susceptibility and other environmental factors and nutritional factors. So our studies are attempting to capture those things as best we can and to look at the relationships among them.
I think that through more understanding of the pathways that are involved in the effects that are observed in relation to early-life exposures, prenatal and early postnatal exposures, that through that understanding we can craft really effective and targeted interventions. Those would include behavioral interventions, educational programs for example, nutritional interventions and people are talking about pharmacological interventions as well.
My area focusing on preventable environmental exposures in my area we tend to think of policy changes that can dramatically affect the environment of a population and actually dealing especially with involuntary exposures that are problematic such as, for example, air pollution. So we think in terms of how scientific data can inform policies, regulatory and other kinds of policies to address those environmental threats.
I mentioned exploring. Really the word is “exploring” the interactions between the environmental exposures, the physical toxicants that we’re interested in and the other factors: genetic susceptibility, nutritional susceptibility, psycho-social stressors, all of which can worsen (exacerbate) the effect of the physical toxicants. Those studies because our cohorts are fairly limited in size we enrolled about 740 women in pregnancy and are following them and their children. Those are fairly limited. We consider them to be exploratory, but it’s important to attempt to assess those at this point and then hopefully we’ll be able to do larger studies in the future.