The Researcher's Perspective Podcast Interview with Retha Newbold Views and opinions expressed in these podcasts are those of the interview subjects and do not necessarily reflect the views, opinions, or policies of EHP or of the National Institute of Environmental Health Sciences. Narrator: EHP presents The Researcher's Perspective. Ernie Hood: Hello again. I'm your host, science writer Ernie Hood. On this episode of The Researcher's Perspective, we welcome Retha Newbold to the program. She is a staff scientist and developmental biologist in the Toxicology Branch at the NIEHS [National Institute of Environmental Health Sciences], where she has been researching environmental estrogens for more than thirty years. She also serves as a National Toxicology Program [NTP] discipline expert in reproductive and developmental toxicology. Recently Ms. Newbold and her co-workers have been investigating the potential reproductive and developmental effects of exposures to bisphenol A, or BPA. Their paper titled "Prenatal Exposure to Bisphenol A at Environmentally-Relevant Doses Adversely Affects the Murine Female Reproductive Tract Later in Life" will appear in the June 2009 issue of EHP. Retha Newbold, thanks for joining us on The Researcher's PerspectiveÉ Retha Newbold: Thanks, Ernie. Ernie Hood: Would you briefly describe the BPA paper in press at this time, and how it adds to our body of knowledge about BPA? Retha Newbold: What we've done in the paper is we've looked at exposure of bisphenol A during prenatal life. This is prenatal life of the mouse. So we've exposed on days 9 and 16 of gestation, and then the animals don't really receive any more exposure. And we just follow them, let them naturally deliver, and then we hold them until about 18 months of age. Eighteen months is usually the length of time; some of these were looked at a little bit before that. But we hold them for an extended period of time, which would correspond to, say, old age for a human. And then we look and see if there are any adverse effects that we can pick up from this type of developmental exposure. Now what we saw with these animals that were exposed just this brief time during development is they had an increase in ovarian problems, say ovarian lesions. They also had some problems in other portions of the reproductive tract. Now we didn't look at other tissues, and it may be that other tissues may have effects, but I am a reproductive and developmental biologist, so I was specifically interested in looking at effects on the reproductive tract. So that's what the study focused on. But you know, out of all the controversy and all the concerns that's going on with BPA, there are very few studies that have looked at long-term effects. This is one of the first times that we've actually looked at long-term effects. Ernie Hood: Tell us a little bit more about your findingsÉ Retha Newbold: In I believe it was 2005, we also looked at neonatal exposure. And in both that paper and this paper, we see changes in the reproductive tract in bisphenol A-exposed animals that we don't see in control animals. Now I'm not talking about a high incidence of lesions, but these are like unusually occurring lesions. And we don't normally see them in controls, so that was our concernÑit's not the number of lesions, but it's the fact that the lesions were occurring at all. Now these lesions or tumors might be something that could be of concern if you were looking at exposures to humans. We just don't have the information as far as long-term exposure to humans. So we sort of have to take the information that we're getting from experimental animals and look to see, are these things that might be affecting human health? Ernie Hood: How do these new findings fit in with the current state of overall deliberations concerning bisphenol A, specifically the FDA's draft report on BPA safety, which declares that BPA exposure through food packaging does not pose an immediate human health threat? Retha Newbold: That's their current concern, but they're also re-examining some of this data, and this is new data that I think will help in future plans for studying BPA, and perhaps for looking at some other reasons for concern. BPA is still a compound that we just don't know that much about, and for sure we don't know that much about its long-term effects. And we really need to be concerned about this, because we know from studies from the CDC that over 90% of the population actually has been exposed to BPA, because we're picking it up in the urine. We also know that it's in a lot of different plastics, so the potential for exposure is quite high. So we need to know what are the long-term effects, if there are truly any adverse effects. And right now the animal studies are leaning toward that direction. Ernie Hood: With so many questions still remaining about the impact on human health of this high production volume, ubiquitous chemical, what do you consider to be the research priorities regarding BPA? Retha Newbold: I think the research priority in particular is, we definitely need more animal studies, we need to understand the mechanisms that are responsible for some of these adverse effects. Whether it's causing lesions, or whether it's just causing any other type of abnormality, we need to know how bisphenol A is causing these effects. But in particular I think one of the major focuses should be on the human population, and coming up with a good, solid epidemiology study where we can actually look and see what humans are exposed to, how much, and when. And that's going to be a little bit more difficult. And those types of studies, I think too, can be built into some of the experimental studies. I'm not really sure with experimental animals whether just doing more and more and more studies is going to help anything. We need to have some defined points, which would be, is there a critical window, and is there a critical tissue that is responding to BPA? We need to know more specific details; just doing more and more studies isn't going to do it. The studies now, we need to focus in and look at specific questionsÑcritical time points, critical windows of exposures, critical tissues that could respond to this. These are things I think that really, really need additional attention. Ernie Hood: You are known for your groundbreaking research on DES, the potent synthetic estrogen used to prevent miscarriages in the late 1940s-to- 1970s. What other chemicals do you think may be worthy of study for the same sorts of effects as seen with DES and BPA? And do you have any plans to initiate new studies involving them? Retha Newbold: There are studies ongoing right now with some of the phthalates. NIEHS, NTP, EPA, a number of the different federal agencies as well as some of the academic labs, and government agencies and the pharmaceutical companiesÑeveryone is interested in looking at effects of environmental endocrine-disrupting chemicals. At this point we're not even sure of all of the chemicals, which ones do have estrogenic activity. I specifically, I'm interested in some of the phthalates, I'm interested in, there would be compounds specifically in cosmetics, things like this. Also we know that it's not only just synthetic chemicals that may be having a problem, but there are some chemicals that naturally occur in the environmental that have estrogenic activity, for example some of the components in soy products. One of those in particular is genistein. Genistein is found in soy products. So that is something that I am interested in right now, and my main reason for this is because of the potential for fetal and early neonatal exposures. Some of these things, we don't even know what all of them are in the environment that have estrogenic activity, but the ones that most concern me are the ones where we have the potential for fetal and early childhood exposures. Those are the ones that really are the most important, the ones that we should be most concerned about. Ernie Hood: Retha Newbold, thank you so much for joining us on this edition of The Researcher's Perspective. Retha Newbold: Thank you, Ernie. I appreciate the time. Ernie Hood: And thank you for listening to this edition of The Researchers Perspective, the EHP podcast. Join us again next time as we explore another unique perspective in the environmental health sciences!