Fetal BPA exposure increases risk of prostate cancer later in life

Fetal exposure to a commonly used chemical found in products such as water bottles, soup can liners and paper receipts can increase the risk for prostate cancer later in life, according to a study from the University of Illinois at Chicago.

Bisphenol A, or BPA, is widely used to soften plastics. Steering clear of the chemical is nearly impossible, says Gail Prins, professor of physiology at UIC and lead author of the paper.

“Previous studies have shown that people who avoided all contact with plastics or other BPA-containing objects for up to a month or more still had BPA in their urine, which means they must have come into contact with BPA in the last 24 to 48 hours, since it clears the body rather quickly,” said Prins, who is director of the UIC andrology laboratory. “It’s very hard to avoid.”

Exposure of the fetus to BPA in utero is of particular concern, because the chemical, which mimics the hormone estrogen, has been linked to several kinds of cancer, including prostate cancer, in rodent models. The new findings show that human prostate tissue is also susceptible.

“Our research provides the first direct evidence that exposure to BPA during development, at the levels we see in our day-to-day lives, increases the risk for prostate cancer in human prostate tissue,” Prins said. “The findings of adverse effects of BPA in human tissue are highly relevant and should encourage agencies like the Food and Drug Administration to re-evaluate their policies in the near future.”

Prins investigated the effect of BPA on human cells by implanting human prostate stem cells taken from deceased young-adult men into mice. Prostate stem cells are very long-lived. They arise during early fetal development and produce and maintain a man’s prostate tissue throughout his life.

To mimic exposure to BPA during embryonic development, for two weeks following implantation the mice were fed BPA — in amounts in line with those seen in pregnant American women — as the cells produced humanized prostate tissue.

“The amount of BPA we fed the mice was equivalent to levels ingested by the average person,” Prins said. “We didn’t feed them exorbitantly high doses.”

After the tissue was allowed to mature for one month, the mice were given estrogen to mimic the naturally rising estrogen levels seen in aging men. This rise in estrogen later in life is one of the known drivers of prostate cancer.

Tissue was collected after two to four months and analyzed for prostate disease. Prins found that a third of tissue samples taken from mice fed BPA had either pre-cancerous lesions or prostate cancer, compared to only 12 percent in a control group of mice fed oil. If the prostate stem cells were exposed to BPA before implantation and again as they produced prostate tissue in the mice, 45 percent of the tissue samples had pre-cancerous lesions or cancer.

“We believe that BPA actually reprograms the stem cells to be more sensitive to estrogen throughout life, leading to a life-long increased susceptibility to diseases including cancer,” Prins said.

The study was published in the journal Endocrinology.

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High BPA Levels in Children Associated with Higher Risk of Obesity

Photo: Claire Bloomfield/freedigitalphotos.net

Children who have higher levels of Bisphenol A (BPA), a chemical previously used in many products for kids, like baby bottle and plastic toys, had a higher odds of obesity and adverse levels of body fat, according to a new study from University of Michigan researchers.

The U-M team studied the levels of BPA found in children’s urine and then measured body fat, waist circumference, and cardiovascular and diabetes risk factors, in a study published today in Pediatrics.

BPA was previously widely used in the manufacturing of polycarbonate and epoxy resins used in a variety of products for children, including baby bottles, protective coatings on metal food containers, plastic toys, and dental sealants.

“Studies in adults had shown an association between high BPA levels and obesity, diabetes and cardiovascular disease, but little was known about its effects in children,” says Donna Eng, M.D., lead author of the study and recent graduate of the Pediatric Endocrinology Fellowship at C.S. Mott Children’s Hospital.

The study found that higher odds of obesity, defined as a BMI above the 95th percentile on Centers for Disease Control and Prevention growth curves, was associated with higher levels of urinary BPA. Researchers also found that children with higher BPA levels also were more likely to have an abnormal waist circumference-to-height ratio.

The study did not find significant associations of BPA with any other chronic disease factors, including abnormal levels of cholesterol, insulin or glucose levels.

“Our study suggests a possible link between BPA exposure and childhood obesity. We therefore need more longitudinal studies to determine if there is a causal link between BPA and excess body fat.” says Eng.

Manufacturers have been voluntarily recalling BPA products due to suspicion about the toxic effects on children and other vulnerable populations. Many countries, including Canada and members of the European Union, as well as several U.S. states, have banned BPA use in products frequently used by infants and young children.

In July 2012, the U.S. Food and Drug Administration announced that baby bottles and children’s drinking cups could no longer contain BPA; however, this restriction does not apply to other BPA containing products.

“We were surprised that our study did not find an association between BPA and measures of cardiovascular and diabetes risk, which has been established among adults,” says Joyce Lee, M.D., M.P.H, associate professor of Pediatrics at C.S. Mott Children’s Hospital.

“Based on these results, BPA may not have adverse effects on cardiovascular and diabetes risk, but it’s certainly possible that the adverse effects of BPA could compound over time, with health effects that only later manifest in adulthood,” says Lee, an investigator in U-M’s Child Health Evaluation and Research Unit and assistant professor of Environmental Health Sciences in the U-M School of Public Health.

Investigators hope the study will prompt more research into BPA’s effects that can inform future policy regulating children’s consumer products.

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BPA linked to a common birth defect in boys

A new study links fetal exposure to a common chemical pollutant, bisphenol A (BPA), to defects of a testicular hormone in newborn boys with undescended testicles. The results, which were presented Monday at The Endocrine Society's 95th Annual Meeting in San Francisco, suggest yet another potential harmful effect of BPA, which is widely used in many plastics, liners of food cans and dental sealants.

"Alone, our study cannot be considered as definitive evidence for an environmental cause of undescended testis," said lead author Patrick Fenichel, MD, PhD, professor and head of reproductive endocrinology at the University Hospital of Nice in France. "But it suggests, for the first time in humans, a link that could contribute to one co-factor of idiopathic [unexplained] undescended testis, the most frequent congenital malformation in male newborns."

Cryptorchidism, the medical name for undescended testicles, occurs in 2 to 5 percent of full-term male newborns, according to Fenichel. Sometimes the testicles descend on their own within six months after birth. If the condition persists and goes untreated, however, it carries an increased risk in adulthood of decreased fertility and testicular cancer, he said.

Fenichel and his colleagues studied 180 boys born after 34 weeks' gestation between 2003 and 2005. Fifty-two were born with one or two undescended testicles, 26 of whom still had the condition at 3 months of age. The other 128 newborns did not have this birth defect and were matched for pregnancy term, weight and time of birth (the control group). Using sensitive immunoassays of the infants' umbilical cord blood, the researchers measured the newborns' levels of BPA and insulin-like peptide 3, one of the two testicular hormones that regulate descent of the testicles.

Testosterone level, which also controls fetal testicular descent, did not differ between the groups and was normal in the whole population, according to Fenichel.

The infants with cryptorchidism had significantly lower levels of insulin-like peptide 3, compared with the controls, the authors reported. These infants did not have greatly increased levels of BPA or several other environmental endocrine disrupters that were measured. However, in all 180 infants, the BPA level inversely correlated with the level of insulin-like peptide 3, meaning that the higher the BPA level, the lower the level of this important testicular hormone.

Fenichel speculated that BPA, an estrogenic endocrine disruptor, might repress, as other research has shown for estrogens in rodents, expression of the gene for insulin-like peptide 3. This could be a co-factor in the development of cryptorchidism, he said.

Animal research also has linked fetal BPA exposure to an increased risk of reproductive disorders and other health problems.

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Early exposure to bisphenol A might damage the enamel of teeth

photo: antpkr/freedigitalphotos.net

Are teeth the latest victims of bisphenol A? Yes, according to the conclusions of work carried out by the research team led by Ariane Berdal of the Université Paris-Diderot and Sylvie Babajko, Research Director at Inserm Unit 872 "Centre des Cordeliers". The researchers have shown that the teeth of rats treated with low daily doses of BPA could be damaged. Analysis of the damage shows numerous characteristics that are common with a recently identified pathology of tooth enamel that affects roughly 18% of children between the ages of 6 and 8.

Bisphenol A (BPA) is a chemical compound used in the composition of plastics and resins. It is used for example to manufacture food containers such as bottles or babies' bottles. It is also used for the protective films inside drinks cans and food tins, or as developers on sales receipts. Significant amounts of BPA have also been found in human blood, urine, amniotic liquid and placentas. Recent studies have shown that this industrial compound has adverse effects on the reproduction, development and metabolism of laboratory animals. It is strongly suspected of having the same effects on humans.

As a precautionary measure, the manufacture and commercialization of babies' bottles containing bisphenol A were prohibited in Canada in 2010 and in Europe in 2011. The prohibition will be extended to all food containers in France as from July 2015 and Canada is looking to follow suit.

Analysis of the teeth showed numerous characteristics in common with a tooth enamel pathology known as MIH (Molar Incisor Hypomineralisation) that selectively affects first molars and permanent incisors. This enamel pathology is found in roughly 18% of children between the ages of 6 and 8. Children affected by this pathology present with teeth that are hypersensitive to pain and liable to cavities. It is interesting to note that the period during which these teeth are formed (the first years of life) correspond to the period during which humans are most sensitive to bisphenol A.

Amongst the earliest observations made was the appearance of "white marks" on the incisors of rats treated with endocrine disruptors, one of which was bisphenol A (BPA). The researchers decided to define the characteristics of incisors of rats treated with low doses of BPA and to compare these with the characteristics of teeth in humans suffering from MIH.

Macroscopic observation of marks on both series of teeth showed similarities, in particular fragile and brittle enamel.

Microscope observation of the enamel showed a significant reduction of the Ca/P and the Ca/C ratios in affected teeth. This leads to mineral depletion, making the teeth more fragile and more liable to cavities.
Finally, analysis of the proteins present in the tooth matrix of rats showed an increased quantity of enamelin, a key protein for enamel formation, and a buildup of albumin leading to hypomineralisation. Analysis of the expression of key enamel genes highlighted two BPA target genes: enamelin and kallicrein 4.

According to Sylvie Babajko, the latest author of this article, "Insofar as BPA has the same mechanism of action in rats as in men, it could also be a causal agent of MIH. Therefore, teeth could be used as early markers of exposure to endocrine disruptors acting in the same way as BPA and so could help in early detection of serious pathologies that would otherwise have occurred several years later".

These results have been published in the American Journal of Pathology.

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Chemicals pollutants threaten health in the Arctic

Photo: Danilo Rizzuti freedigitalphotos.net

People living in Arctic areas can be more sensitive to pollutants due to their genetics, says researcher Arja Rautio at the Centre for Arctic Medicine in the University of Oulu, Finland. This is unfortunate since the northernmost areas of Europe are receiving more harmful chemical exposure. Scientists believe climate change may be a culprit as air and water mass movements push some of these undesirable chemicals towards the Arctic.

“In real life, people are exposed to lots of chemicals,” says Rautio, who leads studies into the human health effects from contaminants and the influence of climate change in a EU-funded project called ArcRisk, “and I think the people of the north are exposed to higher levels than for example the general population in Europe.”

Many new contaminants like fluorinated and brominated compounds and bisphenol A can act on hormones and so have impacts on human health. But seeing an effect on humans, at the population level, could take ten or even 20 years, especially in the case of cancer, she adds. This is why ArcRisk has established a database containing data on concentration levels and trends of contaminants in humans. The project team analysed frozen blood samples collected in Norway in 1978, 1986, 1995 and 2008 for polychlorinated biphenyls (PCBs), chlorinated pesticides and polybrominated diphenylethers (PBDEs).

The main challenge that project scientists struggle with is to disentangle the effects of contaminant chemicals from what we do in our everyday lives. “We know that dioxins can lead to more diabetes and high blood pressure,” says Rautio, “but there are many other confounding factors. We are changing our diet and many of us are less active and those lifestyle choices can also increase the risk of diseases like diabetes.” The results of the project are due to be presented at a conference of Arctic Frontiers in Tromsø, Norway, in January 2014.

Previous studies have also struggled with disentangling contaminants effects when trying to understand their impact on health. There are uncertainties between the chemicals and direct health impacts because people are exposed to so many chemicals simultaneously, cautions biologist Thomas Zoeller at the University of Massachusetts Amherst, USA. Besides, the human population is genetically variable and may react differently to the chemicals and we don’t even know which of the chemicals affect us.

“Moreover, some of these chemicals reside in the environment – and in the body – for a long time, and this means that they may build up,” says Zoeller. His recently edited a recent World Health Organization report which warned that chronic diseases are increasing worldwide and many are related to hormones. It noted that known hormone-disrupting chemicals are “only the tip of the iceberg” and better tests are needed to catch others.

Health problems induced by these chemicals could be worse than anticipated. Some of the pollutants found in the Arctic by the project scientists like the fluorinated compounds have higher affinities for hormone receptors than even the natural hormones. “We have documented several direct harmful effects of these and other chemicals, especially in seabirds, top predators such as the glaucous and ivory,” says Geir Wing Gabrielsen, an environmental scientist at the Norwegian Polar Institute, who is not part of ArcRisk.

These animal studies already show worrying trends that do not bode well for humans. “When we see these findings in Arctic animals I am very concerned about what we will find with regards to humans, though we ourselves don’t do human studies,” Gabrielsen says. He notes that long periods of warm air are being transported to the Arctic and that the sea currents around places like the Svalbard islands [located midway between Norway and the North Pole] now consist of warmer Atlantic water; they used to consist of polar waters. “Climate change is having an effect and it is resulting in higher levels of contaminants in the environment and [therefore] also in the animals,” Gabrielsen warns.

Rautio concludes that there is a need to clarify the effects so that people—not only in those living in the remote northern areas— can make decisions about their own lives, what to eat, how to avoid exposure to harm.

Source: European Research Media Center, www.youris.com

BPA raises risk for childhood asthma

Children exposed to the plastics chemical bisphenol A had an elevated risk for asthma

Researchers at the Columbia Center for Children's Environmental Health at the Mailman School of Public Health are the first to report an association between early childhood exposure to the chemical bisphenol A (BPA) and an elevated risk for asthma in young children. BPA is a component of some plastics and is found in food can liners and store receipts.

Results appear in the March edition of the Journal of Allergy and Clinical Immunology.

"Asthma prevalence has increased dramatically over the past 30 years, which suggests that some as-yet-undiscovered environmental exposures may be implicated. Our study indicates that one such exposure may be BPA," says lead author Kathleen Donohue, MD, an assistant professor of Medicine at Columbia University College of Physicians and Surgeons and an investigator at the Center for Children's Environmental Health.

Dr. Donohue and her co-investigators followed 568 women enrolled in the Mothers & Newborns study of environmental exposures. BPA exposure was determined by measuring levels of a BPA metabolite in urine samples taken during the third trimester of pregnancy and in the children at ages 3, 5, and 7. Physicians diagnosed asthma at ages 5 to 12 based on asthma symptoms, a pulmonary function test, and medical history. A validated questionnaire was used to evaluate wheeze.

After adjusting for secondhand smoke and other factors known to be associated with asthma, the researchers found that post-natal exposure to BPA was associated with increased risk of wheeze and asthma. BPA exposure during the third trimester of pregnancy was inversely associated with risk of wheeze at age 5. This unexpected finding is in contrast to the results of a previous study, which found that BPA exposure during the second trimester, a critical period for the development of airways and the immune system, was positively linked with risk for asthma.

Increased risk for wheeze and asthma was seen at "fairly routine, low doses of exposure to BPA," says Dr. Donohue. "Like most other scientists studying BPA, we do not see a straightforward linear dose-response relationship."

At all three time points, more than 90% of the children in the study had detectable levels of BPA metabolite in their bodies, a finding that is in line with previous research. This does not mean that they will all develop asthma, cautions Dr. Donohue. "Just as smoking increases the risk of lung cancer but not everyone who smokes gets lung cancer, not every child exposed to BPA will develop asthma."

The biological mechanism behind the BPA-asthma connection is unclear. The current study found no evidence that exposure to BPA increased the risk that the immune system would develop more antibodies to common airborne allergens. "Other possible pathways may include changes to the innate immune system, but this remains an open question," says Dr. Donohue.

The new study builds on existing evidence linking BPA exposure to respiratory symptoms, as well as to obesity, impaired glucose tolerance, and behavioral issues, among a range of health problems. In July, the Food and Drug Administration banned BPA in baby bottles and sippy cups.

"It is very important to have solid epidemiologic research like ours to give the regulators the best possible information on which to base their decisions about the safety of BPA," says senior author Robin Whyatt, DrPH, professor of Environmental Health Sciences and deputy director of the Columbia Center for Children's Environmental Health.

To reduce exposure to BPA, the National Institute of Environmental Health Sciences (NIEHS) recommends avoiding plastic containers numbers 3 and 7, eating less canned food, and, when possible, choosing glass, porcelain, or stainless steel containers, especially for hot food and liquids.

Chemical exposure despite organic diet and plastic-free food containers

While water bottles may tout BPA-free labels and personal care products declare phthalates not among their ingredients, these assurances may not be enough. According to a study published February 27 in the Nature Journal of Exposure Science and Environmental Epidemiology, we may be exposed to these chemicals in our diet, even if our diet is organic and we prepare, cook, and store foods in non-plastic containers. Children may be most vulnerable.

“Current information we give families may not be enough to reduce exposures,” said Dr. Sheela Sathyanarayana, lead author on the study and an environmental health pediatrician in the UW School of Public Health and at Seattle Children’s Research Institute. She is a physician at Harborview Medical Center’s Pediatric Environmental Health Specialty Unit, and a UW assistant professor of pediatrics.

Phthalates and bisphenol A, better known as BPA, are synthetic endocrine-disrupting chemicals. Previous studies have linked prenatal exposure to phthalates to abnormalities in the male reproductive system. Associations have also been shown between fetal exposure to BPA and hyperactivity, anxiety, and depression in girls.

The researchers compared the chemical exposures of 10 families, half of whom were given written instructions on how to reduce phthalate and BPA exposures. They received handouts prepared by the national Pediatric Environmental Health Specialty Units, a network of experts on environmentally related health effects in children. The other families received a five-day catered diet of local, fresh, organic food that was not prepared, cooked or stored in plastic containers.

When the researchers tested the participants’ urinary concentrations of metabolites for phthalates and BPA, they got surprising results. The researchers expected the levels of the metabolities to decrease in those adults and children eating the catered diet.

Instead, the opposite happened. The urinary concentration for phthalates were 100-fold higher than the those levels found in the majority of the general population. The comparison comes from a study conducted by the National Health and Nutrition Examination Survey. This is a program of studies managed by the Centers for Disease Control and Prevention and designed to assess the health and nutritional status of adults and children in the United States.

The concentrations were also much higher for children as compared to the adults. The researchers then tested the phthalate concentrations in the food ingredients used in the dietary intervention. Dairy products—butter, cream, milk, and cheese—had concentrations above 440 nanograms/gram. Ground cinnamon and cayenne pepper had concentrations above 700 ng/g, and ground coriander had concentrations of 21,400 ng/g.

“We were extremely surprised to see these results. We expected the concentrations to decrease significantly for the kids and parents in the catered diet group. Chemical contamination of foods can lead to concentrations higher than deemed safe by the US EPA,” said Dr. Sheela Sathyanarayana.

Using the study results, the researchers estimated that the average child aged three to six years old was exposed to 183 milligrams per kilogram of their body weight per day. The U.S. Environmental Protection Agency’s recommended limit is 20 mg/kg/day.

“It’s difficult to control your exposure to these chemicals, even when you try,” said Sathyanarayana. “We have very little control over what’s in our food, including contaminants. Families can focus on buying fresh fruits and vegetables, foods that are not canned and are low in fat, but it may take new federal regulations to reduce exposures to these chemicals.”

BPA May Affect the Developing Brain

Environmental exposure to bisphenol A (BPA), a widespread chemical found in plastics and resins, may suppress a gene vital to nerve cell function and to the development of the central nervous system, according to a study led by researchers at Duke Medicine.

The researchers published their findings - which were observed in cortical neurons of mice, rats and humans - in the journal Proceedings of the National Academy of Sciences on Feb. 25, 2013.

"Our study found that BPA may impair the development of the central nervous system, and raises the question as to whether exposure could predispose animals and humans to neurodevelopmental disorders," said lead author Wolfgang Liedtke, M.D., PhD, associate professor of medicine/neurology and neurobiology at Duke.

BPA, a molecule that mimics estrogen and interferes with the body's endocrine system, can be found in a wide variety of manufactured products, including thermal printer paper, some plastic water bottles and the lining of metal cans. The chemical can be ingested if it seeps into the contents of food and beverage containers.

Research in animals has raised concerns that exposure to BPA may cause health problems such as behavioral issues, endocrine and reproductive disorders, obesity, cancer and immune system disorders. Some studies suggest that infants and young children may be the most vulnerable to the effects of BPA, which led the U.S. Food and Drug Administration to ban the use of the chemical in baby bottles and cups in July 2012.

While BPA has been shown to affect the developing nervous system, little is understood as to how this occurs. The research team developed a series of experiments in rodent and human nerve cells to learn how BPA induces changes that disrupt gene regulation.

During early development of neurons, high levels of chloride are present in the cells. These levels drop as neurons mature, thanks to a chloride transporter protein called KCC2, which churns chloride ions out of the cells. If the level of chloride within neurons remains elevated, it can damage neural circuits and compromise a developing nerve cell's ability to migrate to its proper position in the brain.

Exposing neurons to minute amounts of BPA alters the chloride levels inside the cells by somehow shutting down the Kcc2 gene, which makes the KCC2 protein, thereby delaying the removal of chloride from neurons.

MECP2, another protein important for normal brain function, was found to be a possible culprit behind this change. When exposed to BPA, MECP2 is more abundant and binds to the Kcc2 gene at a higher rate, which might help to shut it down. This could contribute to problems in the developing brain due to a delay in chloride being removed.

These findings raise the question of whether BPA could contribute to neurodevelopmental disorders such as Rett syndrome, a severe autism spectrum disorder that is only found in girls and is characterized by mutations in the gene that produces MECP2.

While both male and female neurons were affected by BPA in the studies, female neurons were more susceptible to the chemical's toxicity. Further research will dig deeper into the sex-specific effects of BPA exposure and whether certain sex hormone receptors are involved in BPA's effect on KCC2.

"Our findings improve our understanding of how environmental exposure to BPA can affect the regulation of the Kcc2 gene. However, we expect future studies to focus on what targets aside from Kcc2 are affected by BPA," Liedtke said. "This is a chapter in an ongoing story."

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BPA substitute could spell trouble

A few years ago, manufacturers of water bottles, food containers, and baby products had a big problem. A key ingredient of the plastics they used to make their merchandise, an organic compound called bisphenol A, had been linked by scientists to diabetes, asthma and cancer and altered prostate and neurological development. The FDA and state legislatures were considering action to restrict BPA's use, and the public was pressuring retailers to remove BPA-containing items from their shelves.

The industry responded by creating "BPA-free" products, which were made from plastic containing a compound called bisphenol S. In addition to having similar names, BPA and BPS share a similar structure and versatility: BPS is now known to be used in everything from currency to thermal receipt paper, and widespread human exposure to BPS was confirmed in a 2012 analysis of urine samples taken in the U.S., Japan, China and five other Asian countries.

According to a study by University of Texas Medical Branch at Galveston researchers, though, BPS also resembles BPA in a more problematic way. Like BPA, the study found, BPS disrupts cellular responses to the hormone estrogen, changing patterns of cell growth and death and hormone release. Also like BPA, it does so at extremely low levels of exposure.

"Our studies show that BPS is active at femtomolar to picomolar concentrations just like endogenous hormones —that's in the range of parts per trillion to quadrillion," said UTMB professor Cheryl Watson, senior author of a paper on the study now online in the advance publications section of Environmental Health Perspectives. "Those are levels likely to be produced by BPS leaching from containers into their contents."

Watson and graduate student René Viñas conducted cell-culture experiments to examine the effects of BPS on a form of signaling that involves estrogen receptors — the "receivers" of a biochemical message — acting in the cell's outer membrane instead of the cell nucleus. Where nuclear signaling involves interaction with DNA to produce proteins and requires hours to days, membrane signaling (also called "non-genomic" signaling) acts through much quicker mechanisms, generating a response in seconds or minutes.

Watson and Viñas focused on key biochemical pathways that are normally stimulated when estrogen activates membrane receptors. One, involving a protein known as ERK, is linked to cell growth; another, labeled JNK, is tied to cell death. In addition, they examined the ability of BPS to activate proteins called caspases (also linked to cell death) and promote the release of prolactin, a hormone that stimulates lactation and influences many other functions.

"These pathways form a complicated web of signals, and we're going to need to study them more closely to fully understand how they work," Watson said. "On its own, though, this study shows us that very low levels of BPS can disrupt natural estrogen hormone actions in ways similar to what we see with BPA. That's a real cause for concern."

Chemical Exposure: Study Shows BPA Exposure in Fetal Livers

New research from the University of Michigan School of Public Health found BPA, or bisphenol A, in fetal liver tissue, demonstrating that there is considerable exposure to the chemical during pregnancy.

Researchers also found a proportionately higher concentration of free BPA—as opposed to the conjugated forms modified by the body for elimination—further showing that in fetuses the ability to eliminate the chemical from the body is not the same as in adults.

"The general message from our research is that people have to be cognizant of the fact that the adult body may be able to deal with a particular exposure but a developing fetus may not," said Muna Nahar, doctoral student in the School of Public Health's Department of Environmental Health Sciences and first author on the paper.

Previous animal studies have associated BPA with breast and prostate cancer, and reproductive and behavioral abnormalities. Some research on effects to human health has tied BPA to cardiovascular disease, miscarriage, decreased semen quality and childhood behavioral issues. The chemical also may impact metabolism, diabetes and obesity, although more studies are required to determine its effects.

"The finding of free BPA in fetuses is significant," said Dana Dolinoy, the John G. Searle Assistant Professor of Environmental Health Sciences and senior/corresponding author of the study.

After measuring a three-times-higher concentration of free BPA than the conjugated forms in the fetal livers, the researchers then examined the enzymes responsible for metabolizing the chemical and compared them with those at work in adult male and female livers.

"Our research shows that the argument that it's so rapidly metabolized is not true in fetuses," Dolinoy said.

The study appears online in the Journal of Biochemical and Molecular Toxicology

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New evidence that BPA can disrupt women’s reproductive systems, causing chromosome damage, miscarriages, birth defects

A Washington State University researcher has found new evidence that exposure to the plastic additive BPA can disrupt women’s reproductive systems, causing chromosome damage, miscarriages and birth defects.

Writing in the journal, Proceedings of the National Academy of Sciences, WSU geneticist Patricia Hunt and colleagues at WSU and the University of California, Davis, report seeing reproductive abnormalities in rhesus monkeys with BPA levels similar to those of humans. By using an animal with the most human-like reproductive system, the research bolsters earlier work by Hunt and others documenting widespread reproductive effects in rodents.

"The concern is exposure to this chemical, that we’re all exposed to could increase the risk of miscarriages and the risk of babies born with birth defects like Down Syndrome,” says Hunt. "The really stunning thing about the effect is we’re dosing grandma, it’s crossing the placenta and hitting her developing fetus, and if that fetus is a female, it’s changing the likelihood that that female is going to ovulate normal eggs. It’s a three-for-one hit.”

The research also adds to the number of organs affected by BPA, or bisphenol A, which is found in plastic bottles, the linings of aluminum cans and heat-activated cash register receipts. This May, Hunt was part of another paper in PNAS reporting that the additive altered mammary development in the primate, increasing the risk of cancer.

Hunt’s colleagues at UC, Davis exposed different groups of gestating monkeys to single daily doses of BPA and low-level continuous doses and looked at how they affected the reproductive systems of female fetuses. She saw that in the earliest stage of the adult’s egg development, the egg cell failed to divide properly. Earlier mouse studies showed similar disturbances translated into genetic defects in the mature egg.

A fertilized egg with the wrong number of chromosomes will almost always fail to come to term, leading to a spontaneous abortion or progeny with birth defects.

In monkeys exposed continuously, Hunt saw further complications in the third trimester as fetal eggs were not packaged appropriately in follicles, structures in which they develop. Eggs need to be packaged properly to grow, develop and mature.

"That’s not good,” says Hunt, "because it looks to us like you’re just throwing away a huge number of the eggs that a female would have. It raises concerns about whether or not she’s going to have a really short reproductive lifespan.”