Mexico City's air pollution has detrimental impact on Alzheimer's disease gene

AD: Alzheimer's disease

http://www.eurekalert.org/pub_releases/2015-09/ip-mca092415.php

Public Release: 24-Sep-2015
Mexico City's air pollution has detrimental impact on Alzheimer's disease gene
Affects parents and their children, according to new study in the Journal of Alzheimer's Disease
IOS Press

A new study by researchers at the Universities of Montana, Valle de México, Boise State, and North Carolina, the Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Instituto Nacional de Pediatría, and Centro Médico Cozumel heightens concerns over the detrimental impact of air pollution on hippocampal metabolites as early markers of neurodegeneration in young urbanites carrying an allele 4 of the apolipoprotein E gene (APOE). This is associated with the risk for Alzheimer disease (AD) and a susceptibility marker for poor outcome in traumatic brain injury (TBI) recovery. These findings are published in the Journal of Alzheimer's Disease.

Mexico City children and their parents have lifetime exposures to concentrations of air pollutants above the current USA standards, including fine particulate matter (PM 2.5). Metropolitan Mexico City is an example of extreme urban growth and serious environmental pollution and millions of children are involuntarily exposed to harmful concentrations of PM 2.5 every day since conception.

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Researchers are very concerned by the young age of the children with evidence of a spectral marker of neurodegeneration that is often seen in adults with mild cognitive impairment, in Alzheimer patients and in mouse models of Alzheimer's disease.

Mexico City children, teens, and young adults have shown a key marker of AD: phosphorilated tau along significant brain and intrathecal neuroinflammation, dysregulated immune responses, breakdown of epithelial and endothelial barriers, damage to the neurovascular unit, and brain accumulation of metals associated with combustion. Moreover, these seemingly healthy children have olfaction deficits, dysregulation of feeding regulatory hormones, deficiencies in attention and short-term memory, and below-average scores in Verbal and Full Scale IQ compared to low air pollution children.

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"These results add to growing data suggesting APOE ε4 carriers could have a higher risk of developing early AD if they reside in a polluted urban environment, and unfortunately this statement applies to individuals all around the world with high exposures to air pollutants regardless of ethnicity," added Dr. Calderón-Garcidue?as. The combined effects of residency in a highly polluted city, poor nutrition, urban stress, lower brain and cognitive reserves, and APOE ε4 could lead to an acceleration of neurodegenerative changes.

Air pollution is a serious public health issue and exposures to concentrations of air pollutants at or above the current standards has been linked to neuroinflammation and neurodegeneration. In the USA alone, 200 million people live in areas where pollutants such as ozone and fine particulate matter exceed the standards. Jung et al., 2015 found a 138% risk of increase of AD per increase of 4.34 μg/m3 in PM 2.5 suggesting long-term exposure to PM 2.5, as well as ozone above the current US EPA standards are associated with increased risk of Alzheimer's disease.

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