A team of A*STAR scientists has made a significant breakthrough in understanding how perfluorooctanoic acid (PFOA) is processed by the human body.
The research team used a virtual model that replicates the biological traits of the human body’s chemical processing mechanisms to investigate how PFOA is processed. The team was led by Dr. James Chan. He is the Junior Principal Investigator at A*STAR’s Singapore Institute of Food and Biotechnology Innovation (SIFBI) and the A*STAR Skin Research Labs (A*SRL),
PFOA is an environmental contaminant prevalent in food, food packaging, and consumer products such as non-stick cookware, rugs and cosmetics. It is widely used in various industrial and consumer applications due to its oil-, water-, and heat-resistant properties. Humans are primarily exposed to it through oral ingestion.
It is highly persistent in humans. PFOA has a lengthy half-life of up to four years. This can potentially lead to health concerns. This includes liver and kidney cancer, thyroid issues, developmental effects on the immune and reproductive systems, and fetal development. In Singapore, it appears in 99 per cent of tested blood samples from local cohorts, influencing fertility in women.
Research on the critical levels of PFOA exposure, and how the body eliminates it, is limited, despite the harmful effects. This research sheds light on the biology of PFOA. It also looked at the mechanisms for its high resistance to biological degradation in humans.
It could potentially help the industry design safer replacement chemicals for industrial and consumer products. Regulatory bodies could also employ the findings to measure the impact of PFOA and explore safety limits in products.
PFOA and forever chemicals – what are the findings?
The findings highlight that PFOA binds strongly to blood proteins which act as a magnet. That limits its ability to be filtered by the kidney, thus reducing the speed of its elimination. PFOA resembles the fatty acids that our body needs. As a result, the kidney reabsorbs PFOA from the urine, mistaking it for an essential nutrient. Finally, PFOA uses the same pathway as essential fatty acids to enter our tissues. This allows it to be widely distributed within all body organs, increasing the potential for harm.
By understanding how PFOA persists in the body, these insights could contribute to the development of safer next-generation chemicals for use in various products.
The model is currently being used to investigate the sources of PFOA exposure within the Singapore population. There are plans to expand the use of the model to investigate other Per- and Polyfluoroalkyl Substances (PFAS). PFOA is only one of over 14,000 such chemicals.
What do the findings mean?
This research should help regulatory bodies measure the amount of PFAS in consumer products. The research team has also developed assays that the industry could adopt to test whether their replacement chemicals contain the same properties.
“The data surrounding PFOA is mixed, with some studies suggesting PFOA resides for several months, and others, for years. Our study is the first to provide a rational explanation for these reports by using data of human origin to reveal the true persistence of PFOA in humans. More importantly, it sets forth a general approach that others can use to study PFAS, which we know very little about. There are many more such chemicals that we are exposed to with yet unknown consequences. We hope to work with the broader scientific community to understand their potential for harm and contribute towards better population health,” said Dr. James Chan, senior author of the study.
The paper, “Mechanistic Middle-Out Physiologically Based Toxicokinetic Modeling of Transporter-Dependent Disposition of Perfluorooctanoic Acid in Humans,” was published in Environmental Science & Technology.
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