Bisphenol A (BPA) exposure at certain doses has been linked to increasing rates of asthma, according to new research.
The study - Dose Response of Maternal Exposure to Bisphenol A on the Development of Experimental Asthma in Mouse Pups, by Y. Nakajima et al – found that exposure to the chemical by female mice increased the susceptibility of their offspring to asthma.
In a paper delivered at annual meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) last week, researchers said the study was carried out after previous data had indicated the link between BPA exposure in female mice and the enhanced susceptibility of their pups to allergic asthma.
The group said foetal and postnatal mice were exposed to BPA by maternal loading at different concentrations and the responses in the pups assessed in order to determine this threshold.
They found that maternal exposure to 10 micro g/ml of BPA “enhanced the allergic sensitisation and bronchial inflammation and responsiveness in their pups”. This was significant because the dosage mimics the human BPA burden of chronic exposure, including that of pregnant women, said the researchers from The University of Texas Medical Branch at Galveston.
"The goal of this study was to determine the actual threshold of the effects of BPA on allergic sensitisation, airway inflammation and hyper-responsiveness,” said study co-author Terumi Midoro-Horiuti, MD, PhD
Methodology and results
Female mice received 0, 0.1, 1 and 10 micro g/ml of BPA in their drinking water from one week before pregnancy, during pregnancy and while nursing their pups.
Pups were given one body cavity injection of 5 mg of ovalbumin (OVA) with aluminium hydroxide on day four and 3 per cent OVA nebulisation for 10 minutes on days 18 to 20. On day 22, serum IgE anti-OVA, airway inflammation and hyper-responsiveness were analyzed.
The research found there were “significant increases of airway hyper-responsiveness” in OVA-sensitised pups of mothers fed 10 mg/ml BPA but “no difference in response” among the 0, 0.1, 1 mg/ml BPA groups.
“Maternal exposure to 10 mg/ml BPA enhances allergic sensitisation and bronchial inflammation and responsiveness in pups, but not to lower doses”, concluded the team.