Air pollution exposure damages epithelial and endothelial barriers and is a robust trigger of tight junction and neural antibodies. Cryptic ‘self’ tight junction antigens can trigger an autoimmune response potentially contributing to the neuroinflammatory and Alzheimer and Parkinson’s pathology hallmarks present in megacity children. The major factor determining the impact of neural antibodies is the integrity of the blood-brain barrier. Defining the air pollution linkage of the brain/immune system interactions and damage to physical and immunological barriers with short and long term neural detrimental effects to children’s brains ought to be of pressing importance for public health.

—Calderón-Garcidueñas et al.

Calderón-Garcidueñas and her team compared 58 serum and cerebrospinal fluid samples from a control group living in a low-pollution city and matched them by age, gender, socioeconomic status, education and education levels achieved by their parents to 81 children living in Mexico City.

The results found that the children living in Mexico City had significantly higher serum and cerebrospinal fluid levels of autoantibodies against key tight-junction and neural proteins, as well as combustion-related metals.

We asked why a clinically healthy kid is making autoantibodies against their own brain components. That is indicative of damage to barriers that keep antigens and neurotoxins away from the brain. Brain autoantibodies are one of the features in the brains of people who have neuroinflammatory diseases like multiple sclerosis.

—Dr. Calderón-Garcidueñas

The breakdown of the blood-brain barrier and the presence of autoantibodies to important brain proteins will contribute to the neuroinflammation observed in urban children and raises the question of what role air pollution plays in a 400% increase of MS cases in Mexico City, making it one of the main diagnoses for neurology referrals.

Calderón-Garcidueñas points out that there is a need for a longitudinal follow-up study to determine if there is a relationship between the cognition deficits and brain MRI alterations previously reported in Mexico City children, and their autoimmune responses. What is clear, however, is that the children are suffering from immune dysregulation.

Once there is a breakdown in the blood-brain barrier, not only will particulate matter enter the body but it also opens the door to harmful neurotoxins, bacteria and viruses.

The autoimmune responses are potentially contributing to the neuroinflammatory and Alzheimer’s and Parkinson’s pathology they are observing in young urban children.

While the study focused on children living in Mexico City, others living in cities where there are alarming levels of air pollution such as Los Angeles, Philadelphia-Wilmington, New York City, Salt Lake City, Chicago, Tokyo, Mumbai, New Delhi or Shanghai, among others, also face major health risks. In the US, 200 million people live in areas where pollutants such as ozone and fine particulate matter exceed the standards.

The full article is scheduled to be published in Volume 43, Issue 3 of the Journal of Alzheimer’s Disease and will appear online in December with a 2015 copyright.

The Journal of Alzheimer’s Disease is an international multidisciplinary journal to facilitate progress in understanding the etiology, pathogenesis, epidemiology, genetics, behavior, treatment and psychology of Alzheimer’s disease.

Resources

• Lilian Calderón-Garcidueñas et al. (2015) “Air Pollution and Children: Neural and Tight Junction Antibodies and Combustion Metals, the Role of Barrier Breakdown and Brain Immunity in Neurodegeneration,” (Pre-press) Journal of Alzheimer’s Disease doi: 10.3233/JAD-141365