Air pollution worsens movement disorder after stroke: Study

Air pollution has been shown to have a negative effect on the prognosis of ischemic stroke, or stroke caused by reduced blood flow to the brain, but the exact mechanism is unknown. A team of researchers recently conducted a study to determine whether or not increased inflammation of the brain, also known as neuroinflammation, is the main culprit.

Mice exposed intranasally to urban aerosols from Beijing, China, for one week demonstrated increased neuroinflammation and worsening movement disorder after ischemic stroke, compared to control mice that were not exposed to air pollution. The group went one step further by identifying specific components of air pollution that may directly contribute to lower prognoses in ischemic stroke.

They found evidence that intranasal exposure to air pollution from Beijing, China, increased neuroinflammation after ischemic stroke in mice through activation of microglial cells, which are immune cells found in the brain. Movement disorder was also negatively impacted in ischemic stroke mice exposed to the same air pollution. A second set of experiments replacing Beijing air pollution with PM2.5 from Yokohama, Japan demonstrated similar results, suggesting the PM2.5 fraction of urban air pollution contains the chemical responsible for increased neuroinflammation and decreased ischemic stroke prognosis.

Mice lacking the aryl hydrocarbon receptor demonstrated lower microglial cell activation and movement disorder compared to normal mice, suggesting that the PAHs present in Beijing air pollution are responsible for at least some of the neuroinflammation and lower prognosis seen in ischemic stroke mice exposed to air pollution.

Reference:

Polycyclic aromatic hydrocarbons in urban particle matter exacerbate movement disorder after ischemic stroke via potentiation of neuroinflammation,Particle and Fibre Toxicology, DOI 10.1186/s12989-023-00517-x