Higher levels of bisphenol A (BPA), a plastic commonly used in food packaging, were detected in urine samples taken from women pregnant with boys later found to have autism. Using an analysis of two small studies in people, along with studies of cells in a dish and mice in a lab, Florey researchers identified the biological molecular mechanism underlying this association. Below, Australian researchers comment on the findings.
Journal/conference: Nature Communications
Link to research (DOI): 10.1038/s41467-024-48897-8
Organisation/s: Florey Institute of Neuroscience and Mental Health, Murdoch Children’s Research Institute (MCRI), The University of Melbourne, Hudson Institute of Medical Research, Monash University, Minderoo Foundation, Deakin University, Peter MacCallum Cancer Centre, University of Queensland
Funder: This multimodal project was supported by funding from the Minderoo Foundation. Funding was also provided by the NHMRC, the NHMRC-EU partnership grant for the ENDpoiNT consortium, the Australian Research Council, the Jack Brockhoff Foundation, the Shane O’Brien Memorial Asthma Foundation, the Our Women’s Our Children’s Fund Raising Committee Barwon Health, The Shepherd Foundation, the Rotary Club of Geelong, the Ilhan Food Allergy Foundation, GMHBA Limited, Vanguard Investments Australia Ltd, and the Percy Baxter Charitable Trust, Perpetual Trustees, Fred P Archer Fellowship; the Scobie Trust; Philip Bushell Foundation; Pierce Armstrong Foundation; The Canadian Institutes of Health Research; BioAutism, William and Vera Ellen Houston Memorial Trust Fund, Homer Hack Research Small Grants Scheme and the Medical Research Commercialisation Fund. This work was also supported by Ms. Loh Kia Hui. This project received funding from a NHMRC-EU partner grant with the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement number: 825759 (ENDpoiNTs project). This work was also supported by NHMRC Investigator Fellowships (GTN1175744 to D.B, APP1197234 to A-L.P, and GRT1193840 to P.S).The BIS data custodians, Barwon Health, Deakin University and the Murdoch Children’s Research Institute, provided in-kind support. The study sponsors were not involved in the collection, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication.
Media release
From: Florey Institute of Neuroscience and Mental Health
Florey researchers have found evidence of higher levels of the plastic chemical bisphenol A (BPA) in pregnant mothers who gave birth to sons with autism.Research published in Nature Communications, led by Florey scientists Dr Wah Chin Boon and Professor Anne-Louise Ponsonby, supports the hypothesis of a possible link between autism and exposure to plastic chemicals in the womb.Professor Ponsonby said the researchers analysed two large birth cohorts – the Barwon Infant Study (BIS) in Australia and the Columbia Centre for Children’s Health and Environment in the USA.“Exposure to plastic chemicals during pregnancy has already been shown in some studies to be associated with subsequent autism in offspring,” Professor Ponsonby said.“Our work is important because it demonstrates one of the biological mechanisms potentially involved. BPA can disrupt hormone controlled male fetal brain development in several ways, including silencing a key enzyme, aromatase, that controls neurohormones and is especially important in fetal male brain development. This appears to be part of the autism puzzle.”The study examined children with lower levels of the enzyme aromatase, which in the brain converts testosterone to neuroestrogen, Professor Ponsonby said.The link between BPA presence and autism was particularly evident in the top fifth of boys with vulnerability to the endocrine-disrupting properties of this chemical. That is, those with lower levels of the enzyme aromatase. The study found boys in that group, who were born to mothers with higher urinary BPA levels in late pregnancy were:In laboratory work, Dr Boon studied the impact of prenatal BPA on mice.“We found that BPA suppresses the aromatase enzyme and is associated with anatomical, neurological and behavioural changes in the male mice that may be consistent with autism spectrum disorder,” Dr Boon said.“This is the first time a biological pathway has been identified that might help explain the connection between autism and BPA,” she said.Professor Ponsonby said BPA, similar bisphenols and other plastic chemicals with endocrine-disrupting effects are now widespread and almost impossible for individuals to avoid.“We all ingest plastic chemicals in many ways – through ingesting plastic food and drink packaging, inhaling home renovation fumes, and through the skin from sources such as cosmetics. There are so many ways these chemicals enter our bodies, so, it’s not surprising that BPA was present in a large proportion of the women’s urine samples we studied. It’s important for us to understand how these plastics affect our health,” Professor Ponsonby said.These findings are now feeding into public safety regulators which update safety recommendations on manufactured chemical exposure, including plastic chemicals, during pregnancy and early life.The team also looked for ways to reduce the adverse effect of BPA on the aromatase system.Dr Boon added that a type of fatty acid called 10-hydroxy-2-decenoic acid tested in mice could be worth further investigation.“10-hydroxy-2-decenoic acid shows early indications of potential in activating opposing biological pathways to improve autism-like characteristics when administered to animals that have been prenatally exposed to BPA. It warrants further studies to see whether this potential treatment could be realised in humans.”