National Institute of Environmental Health Sciences

Investing in our Children’s Futures

By Jim Johnson 

One of the greatest threats to children today comes from the environment. Exposure to pesticides, pollution, and heavy metals while in the womb or during early periods of development can cause serious and lifelong health concerns. To protect children from environmental threats and help them live healthier lives, EPA and the National Institute of Environmental Health Sciences (NIEHS) created the Children’s Environmental Health and Disease Prevention Research Centers (Children’s Centers). Teams of multidisciplinary experts at Children’s Centers across the country are looking at how children’s health is impacted by environmental and chemical exposures, epigenetics, non-chemical stressors and other factors with a focus on translating this research into practical information for public use.

Silhouette of children playing outside This year, EPA and NIEHS are awarding five new Children’s Center grants. Research supported under these awards includes the interplay of air pollution, particulate matter and obesity on asthma among inner city children; prenatal and early childhood pollutant exposure and adverse birth outcomes; air pollution, polycylic aromatic hydrocarbons (PAHs) and adolescent cognitive, emotional, behavioral health outcomes; cumulative environmental exposures and increased risk for childhood acute lymphoblastic leukemia; and the effects of environmental contaminants on the microbiome and neurodevelopment.  Each of the newly funded Children’s Centers is receiving between 1.25-1.5 million dollars per year for up to four years.

There are many obstacles to protecting children’s environmental health. Understanding the complexity of these challenges is just one way that EPA and its partners are reducing harmful environmental exposure and making the world a safer place for children and our communities.

About the Author: Dr. James H. Johnson Jr. is the Director of EPA’s National Center for Environmental Research.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Ushering In a New Generation of Chemical Screening

By Richard Judson

I work with EPA colleagues and other scientists around the world to integrate advances in biology, biotechnology, chemistry, and computer science to evaluate thousands of chemicals. Part of our research is supporting EPA’s Endocrine Disruptor Screening Program, exploring the potential for chemicals to disrupt normal growth and development in humans and other animals.

The work we do is helping usher in a new generation of faster, more efficient, and far less costly chemical screening methods. We use automated technologies, called high-throughput screening assays, to expose cells and proteins to chemicals. We then screen them to identify any that exhibited changes in biological activity that may suggest the potential for endocrine disruption.

My partners and I are excited to announce that we have recently published two papers on results of our work. We used the innovative methods described above to screen chemicals for their potential to mimic normal estrogen hormones, substances that direct development and reproduction. Exposure to chemicals that mimic estrogen pose a range of potential health risks, including birth defects and certain types of cancer.

The first paper, published in Nature Scientific Reports, describes the results of screening approximately 10,500 chemicals. The screening included 88 duplicates of the same chemicals, which validated the reliability of the assays. It also included 39 reference chemicals—those whose estrogen-receptor activity have been well established through traditional testing methods. Using the reference chemicals showed that the assays could accurately identify chemicals that were both positive and negative for their ability to mimic natural estrogens.

Robotic arm moving samples for screening

Robotic arm moves samples for automated chemical screening, part of the Tox 21 collaboration.

This paper is a product of Tox21, a federal collaboration pooling expertise and resources among EPA, the National Toxicology Program (National Institute of Environmental Health Sciences), the Food and Drug Administration, and the National Center for Advancing Translational Sciences (NCATS). Tox21 was established to study how high-throughput screening methods can be used to evaluate thousands of chemicals. These assays were run on the NCATS ultra-high-throughput robotic screening system (pictured).

The second paper (selected by the American Chemical Society’s Environmental Science and Technology journal as an editor’s choice) describes the results of screening 1,814 chemicals (including 36 reference chemicals). The screening was performed using a panel of 13 high-throughput estrogen receptor assays that use a diverse set of cell types and assay technologies.The results indicate that such a panel can accurately predict estrogenic responses. It demonstrates how the resulting data could be used for chemical prioritization as part of the Agency’s Endocrine Disruptor Screening Program.

In December 2013, we publicly released our high-throughput screening data through user-friendly web applications called interactive Chemical Safety for Sustainability (iCSS) Dashboards. I encourage anyone with an interest in this research to take a look at the data and to also participate in EPA’s Second ToxCast Data Summit. The summit is scheduled for September 29-30, 2014 in Research Triangle Park, NC.

The goal of the summit is to bring together the user community (industry, non-governmental organizations, academia, governmental agencies and more) to present their ideas for ways to use the large amount of high-throughput screening data to help inform chemical policy and regulatory decisions.

About the Author: EPA scientist Dr. Richard Judson develops databases and computer applications to model and predict toxicological effects of a wide range of chemicals. He is a member of the EPA Computational Toxicology research team where he leads the effort in bioinformatics. Dr. Judson has a BA in Chemistry and Chemical Physics from Rice University and an MA and PhD in Chemistry from Princeton University.

Information About the Papers

Profiling of the Tox21 10K compound library for agonists and antagonists of the estrogen receptor alpha signaling pathway. Ruili Huang, Srilatha Sakamuru, Matt T. Martin, David M. Reif, Richard S. Judson, Keith A. Houck, Warren Casey, Jui-Hua Hsieh, Keith Shockley, Patricia Ceger, Jennifer Fostel, Kristine L. Witt, Weida Tong, Daniel M. Rotroff,2 Tongan Zhao, Paul Shinn, Anton Simeonov, David J. Dix, Christopher P. Austin, Robert J Kavlock, Raymond R. Tice, Menghang Xia. Nature Scientific Reports

Predictive Endocrine Testing in the 21st Century Using in Vitro Assays of Estrogen Receptor Signaling Responses. Daniel M. Rotroff, Matt T. Martin, David J. Dix, Dayne L. Filer, Keith A. Houck, Thomas B. Knudsen, Nisha S. Sipes, David M. Reif, Menghang Xia, Ruili Huang, and Richard S. Judson. Environmental Science & Technology

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Evaluating Studies to Understand if a Chemical Causes Cancer

IRIS graphic identifier

By Kacee Deener

When friends ask me what I do, I always mention the Integrated Risk Information System (IRIS) Program and explain that through IRIS, EPA scientists help protect public health by evaluating scientific information on the health effects that may result from exposure to environmental contaminants.  The questions inevitably come up—how do you do that, and what kind of information do you look at?

Scientists around the world contribute to the knowledgebase about the health effects of chemicals.  A particular area of interest has been chemicals’ potential to cause cancer.

Because EPA’s work must be grounded in the best possible science, we recently updated how we consider some of the cancer research of the Ramazzini Institute (RI), a laboratory in Italy known throughout the world for their extensive work in this area, completing cancer studies for more than 200 compounds.

A few years ago, the National Toxicology Program (NTP) identified differences of opinion between their own scientists and those from the Ramazzini Institute in diagnosing certain types of cancers in a study on methanol.  The scientific community—including EPA—was concerned, since Ramazzini data was included in IRIS evaluations.  We reviewed all of our IRIS assessments to determine which, if any, relied substantially on RI data; we found four that did, and we put those assessments on hold.

To follow up, EPA and the National Institute of Environmental Health Sciences cosponsored a group of scientists with expertise in evaluating tissue samples and making disease diagnoses, a Pathology Working Group (PWG), to review several Ramazzini Institute studies. They found some instances where respiratory infections in Ramazzini study animals made definitive diagnoses difficult, and disagreed with some Ramazzini diagnoses, primarily certain leukemias and lymphomas that had been identified. Therefore, EPA decided not to rely on RI data on lymphomas and leukemias in IRIS assessments. There was agreement, though, in diagnosing solid tumors, and EPA decided to continue to consider Ramazzini Institute solid tumor data in IRIS assessments.

This has been an important issue in the world of chemical risk assessment. Last week, this was highlighted once again when a paper authored by EPA scientists, Scientific Considerations for Evaluating Cancer Bioassays Conducted by the Ramazzini Institute, was published in Environmental Health Perspectives.  The article interprets Ramazzini Institute study results and compares their testing protocols with those used by other federal agencies.  The results were consistent with the PWG findings—Ramazzini Institute results for cancer endpoints other than lymphoma and leukemias, and some cases of tumors of the inner ear and cranium, are generally consistent with those of the National Toxicology Program and other laboratories.  The paper also notes that, while differences in Ramazzini Institute testing protocols can complicate the interpretation of study results, they may also provide chemical risk assessors with insights that might not be observed in other laboratories.

The short answer to my friends’ questions is that EPA works to use the best available science—from across the U.S. and around the world—to support IRIS and our other assessments designed to protect public health.

About the Author:  Kacee Deener is the Communications Director in EPA’s National Center for Environmental Assessment, home of the IRIS Program.  She joined EPA 12 years ago and has a Masters degree in Public Health.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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