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Het slechte van Bisphenol en andere chemicaliŽn*
Verschillende studies laten weer eens de nadelen van bisphenol en andere chemicaliŽn zoals ftalaten als DEHP and DBP en kerosine. Alhoewel in Amerika BPA voor verschillende toepassingen verboden zit het bijvoorbeeld nog in de binnenkant van aluminium drinkbussen.
Uit een studie blijkt dat kinderen met de hoogste urinewaarden aan bisphenol-A (BPA) duidelijk de meeste bloedmerkers hebben voor nierproblemen en hart- en vaatziekte. Uit een studie weliswaar met muizen blijkt dat als de moeder blootgesteld wordt aan BPA de nakomelingen hyperactief worden. Uit een studie met ratten blijkt dat BPA, ftalaten en kerosine blootsteling van de moeder epigenetische verandering doet plaats vinden bij nakomelingen wel drie generaties lang, zonder dat generaties bloot gesteld worden aan de chemicaliŽn. Uit een andere studie blijkt dat kinderen die tijdens hun jeugd blootgesteld worden aan BPA de kans op astma duidelijk hoger is.
BPA linked to potential adverse effects on heart and kidneys
Exposure to a chemical once used widely in plastic bottles and still found in aluminum cans appears to be associated with a biomarker for higher risk of heart and kidney disease in children and adolescents, according to an analysis of national survey data by NYU School of Medicine researchers published in the online issue of Kidney International, a Nature publication.
Laboratory studies suggest that even low levels of bisphenol A (BPA) like the ones identified in this national survey of children and adolescents increase oxidative stress and inflammation that promotes protein leakage into the urine, which is a biomarker for early renal impairment and future risk of developing coronary heart disease, according to Leonardo Trasande, MD, MPP, associate professor of pediatrics, environmental medicine, and population health, and co-lead author of the study.
The study adds to the growing concerns about BPA, which was recently banned by the U.S. Food and Drug Administration but is still used as an internal coating for aluminum cans. Manufacturers say the chemical provides an antiseptic function, but studies have shown the chemical disrupts multiple mechanisms of human metabolism.
"While our cross-sectional study cannot definitively confirm that BPA contributes to heart disease or kidney dysfunction in children, together with our previous study of BPA and obesity, this new data adds to already existing concerns about BPA as a contributor to cardiovascular risk in children and adolescents," says Dr. Trasande. "It further supports the call to limit exposure of BPA in this country, especially in children," he says. "Removing it from aluminum cans is probably one of the best ways we can limit exposure. There are alternatives that manufacturers can use to line aluminum cans."
Children in the United States are exposed to the chemical early in life and surveys have shown that by age six nearly 92 percent of children have some trace of BPA in their urine. Its use has been banned in the European Union and Canada, and in the United States for use in baby bottles and sippy cups. Last September Dr. Trasande's group published a study showing a significant association between obesity and children and adolescents with higher concentrations of BPA in their urine in the Journal of the American Medical Association.
In the new study Dr. Trasande, Teresa Attina, MD, PhD, MPH, and Howard Trachtman, MD, of NYU School of Medicine's Department of Pediatrics, analyzed data on 710 children and adolescents aged 6 to 19 collected in a national survey to assess the health and nutritional status of adults and children in the United States. The data was from the 2009-2010 National Health and Nutrition Examination Survey (NHANES), which contained measurements on urinary BPA, and a protein called albumin, which is not normally found in urine because the spaces in the glomerular membrane of the kidney are too small to allow protein molecules to escape. If there is membrane damage as in some kidney diseases like glomerulonephritis, albumin can leak through into the urine.
The researchers controlled for risk factors such as hypertension, insulin resistance, elevated cholesterol, exposure to tobacco smoke, race/ethnicity, caregiver education, poverty to income ratio, age, weight and gender in these children. Children with the highest amount of BPA in their urine, compared to those with the lowest amount, had a higher albumin to creatinine ratio, a potential early marker of renal impairment and future risk of developing coronary heart disease, according to the study.
"While we excluded children with pre-existing kidney disease from our analysis, I am concerned that BPA exposure may have even greater effects on children with kidney disease," says Dr. Trachtman, co-lead author of the study. "Because their kidneys are already working harder to compensate and have limited functional reserve, they may be more susceptible to the adverse effects of environmental toxins. We clearly need further study of BPA exposure and its effects on the kidney both in healthy children and in children who have pre-existing kidney disease."
The researchers concluded their analysis by emphasizing the need for further research on environmental chemicals and cardiovascular disease, noting that further study may well transform our understanding "from one that focuses on dietary risks to an approach that recognizes the role of environmental chemical factors that may independently impart the risk of Ö future cardiovascular disease."
Provided by New York University School of Medicine
Female mice exposed to BPA by mothers show unexpected characteristics
Female mice exposed to Bisphenol A through their mother's diet during gestation and lactation were found to be hyperactive, exhibit spontaneous activity and had leaner body mass than those not exposed to the chemical, researchers at the University of Michigan School of Public Health have discovered.
BPA is a chemical most commonly found in the lining of food cans and cash register receipts. It once was in many hard plastic bottles, including baby bottles, but many companies have removed it as concerns about exposure have come to light in recent years.
These latest findings from U-M researchers seem to contradict previous studies on BPA that found the chemical to be a factor in obesity. But Dana Dolinoy, the John G. Searle Assistant Professor of Environmental Health Sciences and senior/corresponding author of the study, says research shows that many factors impact how the body reacts to the chemical.
"Our hypothesis going into this study was that BPA would act as an obesogenic agent. And there is some preliminary evidence that it does," Dolinoy said. "But there are differences in exposure, duration and when you actually measure the individual.
"Recent evidence in humans only looks at one time point. What we're really interested in is BPA exposure during early development, and how that affects health throughout life. So those are two very different questions."
The researchers exposed mothers to three different levels of BPA in the diet then followed the offspring through adulthood at three, six and nine months of age. The average lifespan of a mouse is two years, so by three months they are young adults.
"We looked at several different metabolic phenotypes, including spontaneous activity, food intake, energy expenditure and body composition. I think the most striking result we saw was the increased activity in these animals," said Olivia Anderson, doctoral student in environmental health sciences and lead author on the paper published online in the Journal of the Federation of American Societies for Experimental Biology.
"There are several things we need to look at in evaluating studies investigating BPA as an obesogen, such as composition of the diet. Not all these diets are similar throughout these studies. Some may have high-fat diets. Some may have diets with different protein levels. Then there is the difference in exposure timing and doses of exposure of BPA. It's important to dig a little deeper and actually look at the mechanism that BPA is acting upon."
As to why only females exhibited the excessive activity and lean bodies, Dolinoy says it bears more study, but because BPA is known to impact estrogen and thyroid hormone, most likely it is affecting these natural hormones in the females.
Dolinoy's lab is dedicated to the study of environmental epigenetics and nutritionólearning about how exposure to chemical, nutritional and behavioral factors alters gene expression and impacts health and disease.
In December, she and colleagues released a study that found BPA in human fetal liver tissue, demonstrating that there is considerable exposure to the chemical during pregnancy. That research also found that the BPA in fetuses was in a form not eliminated from the body, unlike previous studies that showed adult humans metabolize and rid their bodies of the chemical.
Her work is supported by the U-M Formative Children's Environmental Health and Disease Prevention Center (UM-CEHC) and the U-M Michigan Nutrition and Obesity Research Center (MNORC). MNORC receives funding from the National Institutes of Health, and UM-CEHC from the NIH and the Environmental Protection Agency.
"The work that Olivia Anderson carried out in Dr. Dolinoy's lab is really at the heart of some of the most pressing questions we're trying to solve right now, and their work was a great fit for both centers because it asks and answers questions that are right at the intersection of how toxicants effect health, particularly related to obesity," said Karen Peterson, professor of environmental health sciences at the U-M School of Public Health, director of the CEHC and associate director of MNORC.
More information: "Perinatal Bisphenol A Exposure Promotes Hyperactivity, Lean Body Composition, and Hormonal Responses Across the Murine Life-Course":
Provided by University of Michigan
Plastic products and jet fuel exposures raising incidences of 'epigenetic transgenerational inheritance'
Washington State University researchers have lengthened their list of environmental toxicants that can negatively affect as many as three generations of an exposed animal's offspring.
Writing in the online journal PLOS ONE, scientists led by molecular biologist Michael Skinner document reproductive disease and obesity in the descendants of rats exposed to the plasticizer bisephenol-A, or BPA, as well DEHP and DBP, plastic compounds known as phthalates.
In a separate article in the journal Reproductive Toxicology, they report the first observation of cross-generation disease from a widely used hydrocarbon mixture the military refers to as JP8.
Both studies are the first of their kind to see obesity stemming from the process of "epigenetic transgenerational inheritance." While the animals are inheriting traits conveyed by their parents' DNA sequences, they are also having epigenetic inheritance with some genes turned on and off. Skinner's lab in the past year has documented these epigenetic effects from a host of environmental toxicants, including plastics, pesticides, fungicide, dioxin and hydrocarbons.
The recent PLOS ONE study found "significant increases" in disease and abnormalities in the first and third generations of both male and female descendants of animals exposed to plastics. The first generation, whose mother had been directly exposed during gestation, had increased kidney and prostate diseases. The third generation had pubertal abnormalities, testis disease, ovarian disease and obesity.
The study also identified nearly 200 epigenetic molecular markers for exposure and transgenerational disease. The markers could lead to the development of a diagnostic tool and new therapies.
The Reproductive Toxicology study exposed female rats to the hydrocarbon mixture as their fetuses' gonads were developing. The first generation of offspring had increased kidney and prostate abnormalities and ovarian disease. The third generation had increased losses of primordial follicles, the precursors to eggs, polycystic ovarian disease and obesity.
The study, said Skinner, "provides additional support for the possibility that environmental toxicants can promote the epigenetic transgenerational inheritance of disease."
"Your great-grandmothers exposures during pregnancy may cause disease in you, while you had no exposure," he said. "This is a non-genetic form of inheritance not involving DNA sequence, but environmental impacts on DNA chemical modifications. This is the first set of studies to show the epigenetic transgenerational inheritance of disease such as obesity, which suggests ancestral exposures may be a component of the disease development."
Provided by Washington State University
BPA Raises Risk for Childhood Asthma, Study Finds
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.
The study was supported by grants from the NIEHS (RC2ES018784, R01ES014393, P30ES009089, R01ES08977, and PO1ES09600), U.S. Environmental Protection Agency (R827027, RD832141, and RD834509), and private foundations.
Additional authors include Rachel L. Miller, Matthew S. Perzanowski, Allan C. Just, Lori A. Hoepner, Srikesh Arunajadai, Stephen Canfield, David Resnick, Antonia M. Calafat, and Frederica P. Perera.
De studie. (Februari 2013)