Environmental Factor, December 2011, National Institute of Environmental Health Sciences
Duke symposium tackles later life consequences of early life exposures
By Ian Thomas
Birnbaum set the tone for the meeting in her keynote speech addressing early life exposures. (Photo by Steve McCaw)
Heather Stapleton, Ph.D., an assistant professor of environmental chemistry at Duke and another NIEHS ONES awardee, discussed her research(http://www.niehs.nih.gov/news/newsletter/2011/july/science-infants/index.cfm) on chemical flame retardants. (Photo by Steve McCaw)
Meyer focused on the effects of environmental pollutants on mitochondrial DNA as an area of concern. (Photo by Steve McCaw)
A rainy day at the Washington Duke Inn didn't dampen the enthusiasm of the symposium's speakers or the researchers gathered to hear the latest in exposure science. (Photo by Steve McCaw)
The NIEHS Superfund Research Program at Duke University welcomed toxicologists from around the country, as well as the general public, to the Washington Duke Inn in Durham, N.C., Nov. 4 for a science symposium titled “Early Life Exposures and Later Life Consequences: Mechanisms Underlying Vulnerability.” Highlighted by an array of presentations from several of the Institute's grantees, the daylong event showcased the latest in environmental health research pertaining to the later life effects of early development exposures.
“There are a number of diseases that occur throughout a person's lifespan, which were initiated long before the actual diagnosis,” said NIEHS/NTP Director Linda Birnbaum, Ph.D., the symposium's keynote speaker. “We're seeing this every day, particularly with children. From asthma to learning differences, or even sensitivity to infections, kids today face an increased risk for all of these and more, and much of that can be traced to exposures dating as far back as the prenatal period.”
The environmental connection
As was a common theme throughout the day, new research is drawing an ever-clearer link between environmental exposures and human disease. Perhaps nowhere is this phenomenon more visible than in the dramatic rise of obesity.
“Two-thirds of the adults in our country are overweight, with a body mass index greater than 25, and half of those qualify as obese,” explained Birnbaum. “Some of this can be attributed to the economy, and the fact that less nutritious food is usually the most affordable. However, the research clearly shows that environmental factors, such as paternal exposure to cigarette smoke or car exhaust, are directly connected to this outcome.”
Still, the drastic rise in national obesity is far from the only challenge facing mainstream America today, a point echoed by Irva Hertz-Picciotto, Ph.D.,(http://coeh.berkeley.edu/people/faculty/hertzpicciotto.htm) an autism specialist from the University of California (UC), Davis. “In the last thirty years, the number of autism cases has jumped radically from 1 in 700 kids to roughly 1 in 110,” she said, noting the extreme relevance of these statistics to males. “At present, for every one autistic girl, we're seeing four autistic boys.”
The epigenetic edge
While much of the symposium was devoted to connecting the dots between early environmental exposures and later life disease, another major theme of the meeting involved the need for a broader, research-based understanding of this relationship at the cellular level.
“Epigenetics explains why a skin cell is a skin cell, or a lung cell is a lung cell,” Birnbaum observed. “However, it can also be used to demonstrate how the environment influences our development, because it showcases how these factors alter the expression of our genes.”
NIEHS grantee Joel Meyer, Ph.D.,(http://fds.duke.edu/db/Nicholas/esp/faculty/jnm4) agreed. “Certain types of in utero exposures have alerted us to the importance of mitochondrial DNA as a target of developmental exposure with later life consequences,” said Meyer, an assistant professor of environmental toxicology at Duke and recent NIEHS Outstanding New Environmental Scientist (ONES) awardee. “My concern is that environmental pollutants that affect mitochondria may have similar effects."
Looking through the window
Research has long since shown that different parts of the body have different windows of susceptibility toward illness. However, in recent years it has become increasingly clear that many of these windows are partially, if not solely, dictated by the developmental stage of the tissues under exposure.
“The time of exposure can have very different effects on very different tissues,” Birnbaum concluded. “That's why it's vital for those of us who were trained as toxicologists get beyond the one chemical, one effect paradigm and look at the whole picture, because it's all a function of when these exposures are occurring and where.”
The symposium was supported by the newly refunded NIEHS Superfund Research Center(http://www.nicholas.duke.edu/news/duke-superfund-research-center-receives-12.8-million-grant-renewal) at Duke, in conjunction with the school's Integrated Toxicology and Environmental Health Program(http://toxicology.geneimprint.com/) .
(Ian Thomas is a public affairs specialist with the NIEHS Office of Communications and Public Liaison.)
- Linda Birnbaum, Ph.D., NIEHS/NTP
- Later life consequences of early life exposures
- Heather Stapleton, Ph.D., Duke University
- Exposure to PBDE flame retardants during early development and associated health risks
- Joel Meyer, Ph.D., Duke University
- Mitochondrial DNA as a target of developmental exposures
- Mark Hahn, Ph.D., Woods Hole Oceanographic Institute
- The roles of conditional transcription factors in mechanisms of developmental toxicity: Insights from fish models
- Irva Hertz-Picciotto, Ph.D., UC Davis
- Autism and the environment: Early life risk factors as etiologic clues
- Virginia Rauh, Sc.D., Columbia University
- Seven year neurodevelopment and prenatal exposure to chlorpyrifos, a common agricultural pesticide
- Theodore Slotkin, Ph.D., Duke University
- How early life exposures to common pesticides can lead to metabolic dysfunction, diabetes, and obesity
- Robert Tanguay, Ph.D., Oregon State University
- Defining the role of microRNAs as mediators of developmental toxicity in zebrafish
- Edward Levin, Ph.D., Duke University
- Developmental pesticide impacts on cognitive and emotional function in zebrafish and rats