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DURHAM, N.C., USA: A new study has found that bisphenol A (BPA), a widely used industrial chemical found in hard-plastic bottles and dental resins, affects the development of the central nervous system by disrupting regulation of gene expression. The researchers thus believe that BPA may predispose the development of certain neuro developmental disorders.

Although a number of studies have demonstrated that BPA interferes with the endocrine system and affects the nervous system, the molecular mechanisms underlying this process are not yet clearly understood by scientists. Therefore, the researchers of the current study investigated cortical neurons of mice, rats and humans to determine how BPA induces the changes that disrupt gene regulation.

They found evidence that exposure to BPA may disrupt development of the nervous system by slowing down the removal of chloride from neurons. In early neural development, neurons show high levels of chloride, which drop as the cells mature, and KCC2, a transporter protein, removes chloride from the cells. However, BPA was found to inhibit the gene that synthesizes KCC2, thereby slowing down the removal of chloride from the neurons. If the level of chloride remains elevated, it can damage neural circuits and comprise cells' ability to migrate to their proper position in the brain, the researchers said.

In addition, they found that female neurons were more susceptible to the disrupting effects of BPA. According to the study, the sexually dimorphic effect of BPA on the KCC2 gene was also observed in cortical neurons cultured from the offspring of BPA-fed mouse dams. The researchers thus suggested that BPA may contribute to Rett syndrome, a severe autism spectrum disorder almost exclusively found in girls. The researchers are now planning to investigate the sex-specific effects of the chemical further.

Prior studies have raised concerns that BPA may cause a number of health problems, including behavioral issues, endocrine and reproductive disorders, obesity, cancer and immune system disorders. Some of them have suggested that children are particularly vulnerable to the effects of BPA. Therefore, the Food and Drug Administration banned the use of BPA in baby bottles in 2012.

The study was conducted by medical researchers at the Duke University. It was published online on Feb. 25 in the Proceedings of the National Academy of Sciences of the United States of America ahead of print.