Predicting the Future of Children's Health
EPA's Virtual Embryo project is helping scientists understand how chemical exposure affects a developing embryo.
According to the Centers for Disease Control and Prevention, approximately one in every 33 babies born in the United States is born with a birth defect. Birth defects can heighten the risk of long-term disability as well as increase the risk of illness, potentially impacting a child for the rest of his or her life. Unfortunately, the causes of most birth defects are unknown.
EPA researchers are tapping powerful, high-tech computer systems and models to better determine how prenatal exposure to environmental factors might impact embryo and fetal development. Working on EPA’s Virtual Embryo (v-Embryo™) project, they create computer models of developing body systems and combine them with data from a number of EPA studies and toxicity databases to “virtually” examine the effects of a variety of prenatal exposures.
EPA Speeds Up Chemical Testing Using ToxCast™
Children, for a variety of reasons, can face increased risks for adverse health effects from environmental exposures. To better protect them and others, EPA researchers are working to test thousands of chemicals using the innovative Toxicity Forecaster (ToxCast™).
Since 2007, EPA has been using ToxCast™ to predict the potential toxicity of chemicals and help prioritize chemicals in a more effective and efficient manner.
ToxCast™ is currently screening thousands of chemicals that can be found in a wide variety of places including industrial and consumer products, food additives and pesticides. It uses over 600 rapid, automated tests called high-throughput in vitro assays that screen chemicals for different types of adverse effects such as endocrine disruption, reproductive toxicity, developmental toxicity, cancer, and other disease outcomes. The program is cost-effective because it is faster than traditional testing and helps scientists prioritize which chemicals necessitate further inquiry. Such prioritization reduces the need for animal testing.
Toxcast™ data is publicly available in online, searchable databases.
Virtual Embryo simulates how chemicals and pesticides, including those that disrupt the endocrine system (see Protecting Growth and Development in this issue), interact with important biological processes that could disrupt fetal development. The chemicals used in simulations are identified by EPA’s Toxicity Forecaster (ToxCast - see sidebar) as having the potential to affect development.
The predictions from the computer simulations need to be further tested against non-virtual observations. However, the models provide scientists with a powerful tool for screening and prioritizing the chemicals that need to be more closely examined, greatly reducing the cost and number of targeted studies needed.
“We’ve built small prototype systems, now what we want to do is move into complex systems models that will be more relevant to environmental predictions,” said Thomas B. Knudsen, Ph.D., an EPA systems biologist who is leading the project.
Virtual Embryo models have focused on blood vessel development and limb development, but are being expanded to include early development of the male reproductive system, which is known to be particularly sensitive to endocrine disrupting chemicals.
Knudsen says that having more models is important because different chemicals can affect biological systems in various ways. Luckily, the time it takes to develop new models decreases as researchers’ model-developing knowledge grows.
“The important challenge for us is to try to integrate some of this work with other issues of broad importance to children’s health,” said Knudsen. “We’re focused primarily on embryonic development, but a person doesn’t stop developing at birth. We have to take what we are learning from the embryo and extend that information into life stages beyond birth.”