Environmental exposure to air pollutants during critical periods of development has a more than significant impact on the risk of autism or ASD: this review reveals how common air pollutants, notably fine particles and nitrogen oxide in particular , can trigger complex biological cascades that disrupt brain development.
The lead author, Haitham Amal, professor at the University of Jerusalem, recalls that “different types of neurological disorders, including autism spectrum disorders, can be associated with this environmental factor. The timing of exposure seems crucialwith increased vulnerability during prenatal development and early childhood, during critical neurodevelopmental processes.”
Study identifies several key pathways
by which air pollutants can promote the development of ASD:
- via nitrosative stress orchestrated by nitric oxide (NO);
- via neuroinflammation and oxidative stress pathways;
- via disruption of neurotransmitter systems;
- via epigenetic modifications;
- via interference of the endocrine system:
- via dysregulation of metabolic pathways.
The critical responsibility of PM2.5: Once again, fine particles, including PM2.5 as well as NO products, appear to be of great concern, which can cross the placenta and affect the development of the fetal brain. This will involve implementing real protection measures for pregnant women in more polluted areas, the researchers specify.
“Additional” genetic predispositions: “Our analysis suggests that individuals with a genetic predisposition to ASD may be even more vulnerable to the harmful effects of exposure to air pollution. The interaction between genetic and environmental factors plays a large role in the complex etiology of ASD.
Future risk biomarkers? In utero and early childhood exposure to these pollutants should prompt increased monitoring of neurodevelopment.
New public policies will have to answer these questions: How can urban planning be adapted to protect vulnerable populations? What role for air quality monitoring in prenatal care? What research on the combined effects of multiple pollutants?
Understanding these interactions is essential to developing the right preventive strategies.
Health
Canada
