I Wish I Were Far From the Madding Crowd

March 21, 2010

Epigenetics and environmental health: The emerging science

The more we learn, the more we realize how much we don’t know.  A committee of the National Academy of Sciences held a workshop on July 30–31, 2009, to further understanding of the implications of epigenetic effects on public health and of the research that would be most important for efforts to inform public health leaders about epigenetic effects of chemicals.

What are the human health outcomes when genes (such as a tumor-suppressor gene) are turned on or off at different stages in life and in various tissues? Scientific evidence on animals and humans suggests that epigenetic changes are important and may be passed from one generation to the next.

The newsletter cited below gets a little technical, but provides an excellent overview of issues surrounding epigenetics.  I’ve summarized some of it.  (Most of this is over my head, but I think it’s evidence that we don’t have a full understanding of how the human body works and even less of an idea about how all sorts of environmental factors can affect it.)

Highlights of the meeting

  • What epigenetics is and how it works
  • Differences between genetics and epigenetics during animal development
  • DNA methylation, histone modifications, and transgenerational potential of effects

Possible Causes and Outcomes of Epigenetic Changes

Participants discussed how environmental chemicals, estrogenic compounds, and even social factors, such as child abuse and maternal care, may cause epigenetic changes.

Compounds such as nickel can induce hypermethylation and lead to altered gene expression patterns that can be inherited and lead to a growth or survival advantage for and lead to a growth or survival advantage for cancer cells.

In the late 1990s scientists showed that there was an association between dietary changes and changes in DNA methylation in mice.

Maternal behavior of rats affected DNA methylation of the glucocorticoid receptor gene in the hippocampus of the rat offspring.

One scientist reported that the effects of childhood social adversity on overall methylation patterns were more pronounced than the effects of having a mother who smoked.

Epigenetic changes related to cancer and asthma are being studied.

Possible tools and approaches, such as assay technologies,  for identifying environmental epigenetic stressors.

The following were among the topics discussed: biomarkers of disease susceptibility, animal models for studying epigenetics, screening tools, low-dose responses, interplay between genetics and epigenetics, epigenetic changes as exposure markers

Summary of the meeting by the moderator (p.3)

A half-page table which briefly describes discussion about our understanding of the epigenome and how we might be able to test for epigenetic changes.

Emerging Science for Environmental Health Decisions Newsletter: Use of Emerging Science and Technologies to Explore Epigenetic Mechanisms Underlying the Developmental Basis for Disease (PDF)

Workshop Webcast: Presentations on Emerging Science and Environmental Health

Presentations are available in mp3 (or mp4) and wmv formats.  Some include a PDF version.

Meeting sponsored by the Standing Committee on Use of Emerging Science for Environmental Health Decisions of the National Academy of Sciences Board on Environmental Studies and Toxicology

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