Researchers in Canada have given the FDA something new to think about as it takes a fresh look at the risks of the ubiquitous plastics chemical bisphenol A, or BPA.
Their small lab study is quite different from any that’s been done before, because they tested the chemical directly on cells from human placentas, the organ that delivers nutrition from the mother to the fetus in the womb. EWG’s tests of umbilical cord blood have shown that babies are exposed to BPA even before they’re born.
What the Canadians found is that human placental cells exposed to low levels of BPA in a petri dish were damaged and in some cases killed. The scientists used placentas from five women who had normal pregnancies and exposed cells taken from each of them to various levels of the chemical. Notably, smaller amounts, similar to BPA levels in most people, were more lethal than higher doses.
Here’s an excerpt from a synopsis of the study written by Heather Patisaul, Ph.D. and Wendy Hessler for Environmental Health News:
The cells were exposed to BPA for 24 hours at one of seven different concentrations, ranging from 0.002 to 200 micrograms per milliliter (µg/ml). These doses were selected because they approximate levels of BPA measured in fetal and maternal blood. The researchers then looked to see if BPA exposure damaged the cells.
Release of the protein adenylate kinase was used as a marker of cell death because this protein “leaks” from cells with damaged membranes. Presence of the protein cytokeratin 18 was used as an indicator of apoptosis, a specific type of cell death. Apoptosis is a normal part of placental development, but altering the rate or degree to which this takes place can indicate abnormal placental growth.
What did they find?
Damage to the cell membrane was 1.3 to 1.7 times higher in placental cells exposed to BPA for 24 hours compared to cells that were not exposed to BPA. Apoptosis was 2 to 3 times higher in the BPA-treated cells. These results indicate that cellular development was adversely affected by BPA.
BPA also increased the expression of tumor-necrosis factor alpha (TNF-α), a protein associated with apoptosis. This finding was used as another indicator of increased cell death in the cultured cells. Elevated expression was most pronounced at the lowest, not the highest, BPA exposure levels and provides further evidence that BPA can induce cell death in the placenta. This pattern, known as a non-monotonic (or ‘inverted-U’) dose-response curve, has been observed in multiple experiments with BPA previously and is a characteristic of many endocrine disruptors and endogenous hormones.
In other words, lower doses of BPA were more, not less, damaging.
So does the loss of some placental cells matter? Well, in their account of the study, Patisaul and Hesser pointed out that “damage to the placenta can induce a range of adverse pregnancy outcomes including premature birth, preeclampsia or even pregnancy loss.” Scary.
The lead researchers of the Canadian study, by the way, are Nora Benachour, at the Laboratory of Research in Reproductive and Gestational Health, and Aziz Aris of the Department of Obstetrics-Gynecology at the University of Sherbrooke Hospital Centre, both in Quebec. They published their findings in the journal Toxicology and Applied Pharmacology.
So, let’s see if my math is correct.
We now have the notorious chemical associated with the following ten adverse health affects that afflict millions of Americans of all ages.
Yet, we continue to hear from the chemical industry’s premier apologist for BPA, Steven Hentges, that the hormone-altering chemical is perfectly safe for humans of any age and at any level.
Mr. Hentges told The Washington Post’s Lyndsey Layton just last month that, “The science continues to support the safety of BPA.”
Am I the only one who is reminded of “Irwin Mainway” every time I read a quote from Hentges? You remember Mr. Mainway, president of the Mainway Toy Company, who effortlessly defended any a number of his lethal line of toys as safe for children in a hilarious sketch a few years back on Saturday Night Live? There was Johnny Switchblade – Adventure Punk, Teddy Chainsaw Bear, Mr. Skin Grafter, Doggie Dentist, and who could forget Bag O’ Glass?
In the face of this latest and extremely troubling new study showing that BPA can kill human placental cells, I can’t wait to see what Mr. Hentges pulls from his bag of sound bites.