For years, scientists have warned of the possible negative health effects of bisphenol A, a chemical used to make everything from plastic water bottles and food packaging to sunglasses and CDs. Studies have linked BPA exposure to reproductive disorders, obesity, abnormal brain development as well as breast and prostate cancers.
Mouse experiments by researchers have produced evidence that a mother's exposure to BPA may also increase the odds that her children will develop asthma. Using a well-established mouse model for asthma, the investigators found that the offspring of female mice exposed to BPA showed significant signs of the disorder, unlike those of mice shielded from BPA.
They gave BPA in drinking water starting a week before pregnancy, at levels calculated to produce a body concentration that was the same as that in a human mother, and continued on through the pregnancy and lactation periods.
Four days after birth, the researchers sensitized the baby mice with an allergy-provoking ovalbumin injection, followed by a series of daily respiratory doses of ovalbumin, the main protein in egg white. The investigators then measured levels of antibodies against ovalbumin and quantities of inflammatory white blood cells known as eosinophils in the lungs of the mouse pups. They also used two different methods to measure lung function.
The researchers' were looking for the asthma response to a challenge, something like what might happen if you had asthma and got pollen in your nose or lungs, you might have an asthma attack. All four of the indicators of asthma response showed up in the BPA group, much more so than in the pups of the non exposed mice.
The researchers said that although more work is needed to determine the precise mechanism of that response, it almost certainly has its roots in the property of BPA thought to contribute to other health problems: its status as an "environmental estrogen."
The results showed that they have to consider the possible impact of environmental estrogens on normal immune development and on the development and morbidity of immunologic diseases such as asthma.
The researchers' also need to look at doing more epidemiological studies directly in humans, which is possible because BPA is so prevalent in the environment -- all of us are already loaded with it to a varying extent. For example, it should be possible to determine if children who have more BPA exposure are more likely to develop asthma. |
