The full range of dangers presented by the DNA-damaging endocrine disruptor and neurotoxin Bisphenol-A (BPA) is finally being understood and widely communicated by the scientific community.
It has been linked to obesity, infertility and reproductive disorders in both genders, diabetes, breast cancer, prostate cancer, behavioral problems, liver tumors and more. A Harvard study found a whopping 1200% spike in BPA levels in the urine of people who had recently eaten canned soup, and study after study is showing that harm results at much lower levels than previously thought.
However, even more troubling are the studies revealing that BPA substitutes carry the same level and range of dangers that hoodwink people by labeling "BPA Free" when the presence of bisphenol remains as Bisphenol-S, AP, M, or P.
Following are 3 new studies that highlight the dangers to both humans and nature from the presence of these toxins that are still deemed acceptable by the EPA, which continues to urge that the public does not even have a right to know about where BPA and its substitutes appear.
1. BPA stimulates growth of breast cancer cells, diminishes effect of treatment
Bisphenol A (BPA), a chemical commonly used in plastics, appears to increase the proliferation of breast cancer cells, according to Duke Medicine researchers presenting at an annual meeting of endocrine scientists.
The researchers found that the chemical, at levels typically found in human blood, could also affect growth of an aggressive hormone-independent subtype of breast cancer cells called inflammatory breast cancer and diminish the effectiveness of treatments for the disease.
"We set out to determine whether routine exposures to common chemicals such as those in plastics, pesticides and insecticides could influence the effectiveness of breast cancer treatments," said corresponding author Gayathri Devi, Ph.D., associate professor of surgery at Duke. "BPA was one of the top chemicals to show growth stimulatory effects in breast cancer cells."
Devi and colleagues reported their findings in a featured abstract at the annual joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago, June 23, 2014.
Using new screening strategies, the researchers evaluated a panel of compounds available through a public library of chemicals managed by the Environmental Protection Agency.
The researchers focused on markers in breast cancer cells, specifically those of inflammatory breast cancer, a rare and aggressive form of disease that is difficult to treat.
Screenings identified several agents that appeared to increase the proliferation of inflammatory breast cancer cells. Among the most active was BPA, a chemical known to disrupt hormones. The researchers found that it caused breast cancer cells to grow at a faster rate in both estrogen-receptor positive and estrogen-receptor negative breast cancer cells.
The researchers also found that BPA doses in the range observed in human blood lowered the efficacy of FDA-approved anti-cancer drugs used in breast cancer therapy, notably lapatinib.
"These studies provide the foundation for additional research to develop tools that can be used to identify patients who may be at greater risk of developing treatment resistance," Devi said. "The findings could also lead to biomarkers that identify patients who have heavy exposure to compounds that could diminish the effectiveness of their cancer therapy."
2. Exposure to BPA substitute causes hyperactivity and brain changes in fish
A chemical found in many "BPA free" consumer products, known as bisphenol S (BPS), is just as potent as bisphenol A (BPA) in altering brain development and causing hyperactive behavior, an animal study finds. The results will be presented Sunday at the joint meeting of the International Society of Endocrinology and the Endocrine Society: ICE/ENDO 2014 in Chicago.
BPA has been linked to a wide range of hormone disorders, such as obesity, reproductive cancers and, recently, hyperactivity in children born to women exposed to high levels of this substance during the second trimester of pregnancy. Now, this research in fish found that exposure to BPS, a bisphenol compound, led to hyperactive offspring, just as BPA did.
"BPS, termed the safe alternative to BPA, may be equally as harmful to developing brains," said the study's senior investigator, Deborah Kurrasch, PhD, from Canada's University of Calgary. "Society must place increased pressure on decision makers to remove all bisphenol compounds from manufacturing processes."
The study investigated the effects of BPA and BPS on brain development in zebrafish. This fish is developmentally similar to humans, but the embryo grows externally, enabling researchers to see development of the offspring.
A PhD student in Kurrasch's lab, Cassandra Kinch, exposed zebrafish embryos during the period similar to the second trimester to the exact chemical concentration of BPA found in a local major water source, the Oldman River in Alberta, Canada. This concentration translated to a low dose of BPA for the embryos. By labeling some 5-day-old embryos with molecular markers, she monitored development of the hypothalamus, a powerful region of the brain that controls release of hormones in fish and humans. She counted the number of neurons, or nerve cells, in that brain region and compared it with the number of neurons from fish embryos without BPA exposure.
At the peak time of neuronal birth, the number of neurons in BPA-exposed fish rose 170 percent compared with unexposed fish, Kurrasch stated. In similar experiments using BPS, the number of neurons in exposed fish increased 240 percent. These results, she explained, suggest that BPA and BPS could lead to altered brain connections and might explain the hyperactivity they observed in another experiment. Specifically, the research team used movement tracking software to evaluate behavioral changes in young fish and found that fish exposed during brain development to either BPA or BPS were hyperactive, but unexposed fish were not.
Researchers have thought BPA causes harmful effects by mimicking the female hormone estrogen. However, the Kurrasch lab found another likely cause. They exposed another group of zebrafish to BPA plus various drugs that each block distinct hormone signals. Rather than influencing estrogen signaling pathways, as previously hypothesized, BPA appeared to stimulate neuronal birth by mimicking the male hormone testosterone, which then induced aromatase B, a brain-specific protein recently reported to control the birth of neurons and a key enzyme for estrogen synthesis (production), according to Kurrasch.
"These data provide a new avenue of research to investigate the recent rise in hormone disorders," she said.
3. Common BPA-like chemical, BPS, disrupts heart rhythms in females
Bisphenol S (BPS), a common substitute for bisphenol A (BPA) in consumer products, may have similar toxic effects on the heart as previously reported for BPA, a new study finds. The results were presented Monday at the joint meeting of the International Society of Endocrinology and the Endocrine Society: ICE/ENDO 2014 in Chicago.
In the years since research evidence first showed many potentially damaging health effects of the industrial chemical BPA, some manufacturers have switched to its chemical cousin, BPS, to make hard plastics and other products that they call BPA free, said the study's lead investigator, Hong-Sheng Wang, PhD, from the University of Cincinnati.
Although some BPA-free products contain no bisphenols, Wang said, "BPS is one of the substitutes used in BPA-free products. There is implied safety in BPA-free products. The thing is, the BPA analogs—and BPS is one of them—have not been tested for safety in humans."
BPA is an endocrine (hormone) disrupter that can interfere with the actions of native estrogen and other hormones, but it is not clear whether BPS also is disrupts hormones.
In what Wang called "one of the first assessments of BPS' effect in mammalian primary cells or organs," he and his co-workers tested an environmentally relevant dose of BPS in the hearts of approximately 50 rats. The 1-nanomolar dose was in the range of BPS found in human urine samples in a study by other authors.
In the current study, the investigators perfused, or flowed, BPS through the arteries of each animal's pumping heart, after stimulating the heart with the hormone catecholamine to mimic stress. For a control group, 30 rat hearts received only catecholamine and no BPS.
Exposure to BPS rapidly increased the heart rate of female rats and under the stress condition led to arrhythmias—heart rhythm abnormalities—far greater than in the control rats that did not receive BPS, Wang reported. Electocardiograms demonstrated that BPS caused extra heartbeats and a racing heartbeat, also known as ventricular tachycardia. In male rats, BPS reportedly did not have this rapid impact on the heart.
To determine the cause of the cardiac effects in female rats, the researchers studied cardiac muscle cells from some of the rats. Using studies at the cellular and protein levels, they found that BPS caused abnormal calcium handling, or cycling, which is a key cause of arrhythmias, according to Wang. This action is very similar to the underlying mechanism of BPA's toxic effects on the heart, which Wang and his colleagues showed in a previous study.
The investigators were able to abolish the BPS-induced heart rhythm abnormalities by blocking a type of estrogen receptor (beta) in the female rats. This result shows that "the BPA analog BPS is not necessarily free of endocrine-disrupting activity," Wang said.
"Our findings call into question the safety of BPA-free products containing BPS," he said. "BPS and other BPA analogs need to be evaluated before further use by humans."
Given the prevalence of these chemicals and the lack of willingness by regulatory agencies to take sweeping action, it is imperative to eliminate endocrine-disruptors from your system.