Medical Effects: Air Pollution and the Brain

Brain Inflammation and Alzheimer's-Like Pathology in Individuals Exposed to Severe Air Pollution

Source: Toxicologic Pathology, Volume 32, Number 6, November-December 2004, pp. 650-658(9)

Air pollution is a complex mixture of gases (e.g., ozone), particulate matter, and organic compounds present in outdoor and indoor air. Dogs exposed to severe air pollution exhibit chronic inflammation and acceleration of Alzheimer's-like pathology, suggesting that the brain is adversely affected by pollutants. We investigated whether residency in cities with high levels of air pollution is associated with human brain inflammation. Expression of cyclooxygenase-2 (COX2), an inflammatory mediator, and accumulation of the 42-amino acid form ofbeta-amyloid (Abeta42), a cause of neuronal dysfunction, were measured in autopsy brain tissues of cognitively and neurologically intact lifelong residents of cities having low (n:9) or high (n:10) levels of air pollution. Genomic DNA apurinic/apyrimidinic sites, nuclear factor-kappaB activation and apolipoprotein E genotype were also evaluated. Residents of cities with severe air pollution had significantly higher COX2 expression in frontal cortex and hippocampus and greater neuronal and astrocytic accumulation of Abeta42 compared to residents in low air pollution cities. Increased COX2 expression and Abeta42 accumulation were also observed in the olfactory bulb. These findings suggest that exposure to severe air pollution is associated with brain inflammation and Abeta42 accumulation, two causes of neuronal dysfunction that precede the appearance of neuritic plaques and neurofibrillary tangles, hallmarks of Alzheimer's disease.

Keywords: Brain; beta-amyloid; cyclooxygenase 2; inflammation; neuropathology; air pollution; Mexico City

Document Type: Research article

DOI: 10.1080/01926230490520232

Affiliations: 1: Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico 10: Facultad de Medicina NUCE, Universidad Nacional Autónoma de México, Mexico City, Mexico 11: Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, NC, USA 2: Department of Pediatrics and Center for Environmental Medicine, Asthma and Lung Biology University of North Carolina, USA 3: National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA 4: Departamento de Estadística, Universidad de Valparaíso, Chile 5: Pathology Department, Instituto Nacional de Cancerología, Mexico City, Mexico 6: Hospital de Especialidades No. 25, and Centro de Investigación Biomédica del Noreste CIBIN IMSS, Monterrey, NL, Mexico 7: Hospital de Especialidades No. 25, IMSS, Monterrey, NL, Mexico 8: Escuela Médico Militar, Universidad del Ejército y Fuerza Aérea, Mexico City, Mexico 9: Instituto Nacional de Pediatría, Mexico City, Mexico

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