First study shows air pollution harms the brain
Researchers from Oho State University, Davis Research Center, say long-term exposure to air pollution does more that harm the heart and lungs - it also hurts the brain.
In mouse studies, exposure to fine particulate matter, created by cars, factories and natural dust, was associated with learning and memory problems.
In a separate experiment, mice exposed to polluted air that mimics that of human exposure also showed signs of depression, compared to those not exposed.
Laura Fonken, lead author of the study and a doctoral student in neuroscience at Ohio State University says:
"The results suggest prolonged exposure to polluted air can have visible, negative effects on the brain, which can lead to a variety of health problems."
Past studies have shown a negative impact on cardiovascular and respiratory health.
Fonken notes the study is the first to show the visible effects of air pollution on the brain, which could spell trouble for urban residents. She says:
“This could have important and troubling implications for people who live and work in polluted urban areas around the world.”
Dr. Fonken, along with Qinghua Sun, associate professor of environmental health sciences, and Sanjay Rajagopalan, professor of cardiovascular medicine, previously identified wide spread inflammation that occurs in the body from fine particulate matter – pollution that 1/3 the diameter human hair and reaches deep into the lungs and body organs.
In the current study, the Davis Research Center scientists showed inflammation is evident in the hippocampus of the brain.
In the study, mice were exposed to the same sort of air pollution as humans for 10 months then tested to see if they could find a dark comfortable escape hole, after five days of training. Those exposed to the fine particulate matter were less likely to accomplish the task.
In another experiment, the mice exposed to pollution showed symptoms of depression.
Randy Nelson, co-author of the study and professor of neuroscience and psychology at Ohio State says:
"The more we learn about the health effects of prolonged exposure to air pollution, the more reasons there are to be concerned."
Fine particulate matter from air pollution is linked to diabetes, obesity and hypertension.
The new study shows breathing polluted air can also lead to brain changes – specifically fewer spines in parts of the hippocampus that relate to memory and cognition, shorter fibers called dendrites that act as messenger receptors and overall reduced cell complexity, found in the mouse studies.
Molecular Psychiatry , (5 July 2011) | doi:10.1038/mp.2011.76
"Air pollution impairs cognition, provokes depressive-like behaviors and alters hippocampal cytokine expression and morphology"
L K Fonken, X Xu, Z M Weil, G Chen, Q Sun, S Rajagopalan and R J Nelson
Image credit: Morguefile