Restoring Immunity in Brain after Prenatal Exposure to Environmental Toxin: Scientific Findings

In a groundbreaking study, researchers from the University of Rochester have discovered a potential therapeutic avenue for neurodevelopmental disorders, such as autism and ADHD. The study, published in the prestigious journal Brain, Behaviour, and Immunity, was funded by several esteemed institutes, including the National Institute of Neurological Diseases and Stroke (NINDS), National Institute of Alcohol abuse and Alcoholism (NIAAA), National Institute of Environmental Health Sciences (NIEHS), National Institute of General Medical Sciences (NIGMS), and the National Institute of Child Health and Human Development (NICHD).

The research focused on the industrial byproduct TCDD, primarily released by vehicle exhaust and burning wood, which was found to cause the brain's immune system to malfunction later in life. This malfunction was observed in microglia, crucial cells in the brain's immune system, despite them appearing healthy.

The study, led by Reva Peer, Katheryn Lordy, Matthew McCall, Ph.D., and Cassandra Lamantia, also included co-first authors Rebecca Lowery, Ph.D., assistant research professor at the Del Monte Institute for Neuroscience at the University of Rochester, and Sarah Latchney, Ph.D., of the University of Rochester and St. Mary's College of Maryland. Additionally, Lisa Opanashuk, Ph.D., of the National Institute on Aging, was an author of the study.

The researchers found that exposure to TCDD in utero caused inflammation and malfunction in microglia when responding to injury. However, they also discovered that the drug Pexidartinib (PLX3397) can "shut-off" hyper-responsive microglia, potentially reversing the defects in microglia function resulting from prenatal exposures.

While the study did not specify the exact mechanism by which pharmacological manipulation restores microglia function, it suggests that new microglia that function normally can replace the over-activated microglia. Furthermore, microglia outside the brain during pregnancy may be protected by the blood brain barrier, preventing the harmful effects of TCDD from entering the brain.

The researchers are now interested in understanding if other environmental exposures impact microglia similarly. It's important to note that TCDD is commonly found in meat, dairy, and fish, raising concerns about its potential impact on human health.

In conclusion, this study offers a promising new direction for research into neurodevelopmental disorders. By understanding the effects of TCDD on microglia, scientists may be able to develop effective treatments for these disorders in the future.