Neuroinflammation, hyperphosphorylated tau, diffuse amyloid plaques, and down-regulation of the cellular prion protein in air pollution exposed children and young adults.
Level 4 - case-series / case-control
Post-mortem comparative tissue study (case-control autopsy series)
PubMed 21955814 · doi:10.3233/JAD-2011-110722
What was done
Frontal cortex autopsy samples from children and young adults exposed to air pollution (n = 35) and controls (n = 8) were examined. RT-PCR (n = 43) and microarray profiling (n = 12) assessed gene expression across oxidative stress, DNA damage, NFκB, inflammatory, and neurodegenerative pathways. Neuropathology (tau hyperphosphorylation, diffuse amyloid-β plaques) and APOE genotype interactions were also analyzed.
What was found
Exposed urban residents had >2-fold differential regulation of 134 genes, with upregulation of IL1, NFκB, TNF, IFN, and TLR pathways, and a 15-fold downregulation of cellular prion protein (PrP(C)). In exposed individuals, 40% showed tau hyperphosphorylation with pre-tangle material and 51% exhibited diffuse Aβ plaques, compared to 0% in controls. APOE4 carriers had significantly higher rates of hyperphosphorylated tau and diffuse Aβ plaques compared to APOE3 carriers (Q = 7.82, p = 0.005).
Why it matters
The study provides human tissue evidence that chronic air pollution exposure during youth is associated with early neuroinflammatory signaling and the initiation of Alzheimer's disease-like neuropathology.
Limits
The overall sample size was small (n = 43 total, with only 8 controls and 12 microarray samples). The cross-sectional autopsy design cannot establish causality or track progression over time, and the abstract does not report quantitative exposure metrics, specific causes of death, or adjustments for socioeconomic and lifestyle confounders.
Cited by
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