POLLUTION: Inhaled particles pass directly from the lungs to the brain

Recent studies have revealed a strong link between high levels of air pollution and marked neuroinflammation, Alzheimer-like features and cognitive disorders in the elderly or in children.

This discovery of a possible direct route, taken by different inhaled fine particles, and via the bloodstream to reach the brain, completes this previous data. Scientists thus confirm the presence of various fine particles in human cerebrospinal fluids, taken from patients suffering from brain disorders, and shed light on the process leading to the arrival of toxic particulate substances in the brain. Professor Iseult Lynch, author and researcher at the University of Birmingham comments on this work: “There are major gaps in our knowledge of the harmful effects of fine airborne particles on the central nervous system. Our work sheds new light on the link between the inhalation of particles and their possible effects on the brain”.

Fine particles pass mainly through the blood

The study reveals, in particular, that 8 times more fine particles can reach the brain, from the lungs and through the bloodstream, than by passing directly through the nose. Ambient fine particles such as PM2.5 and PM0.1 are of greatest concern in terms of adverse health effects. These particles are in fact capable of escaping the body’s protection systems (sentinel immune cells and biological barriers).

The team shows that inhaled particles can damage the blood-brain barrier and surrounding tissues. Once in the brain, the particles are difficult to eliminate and persist longer than in other organs.

This work provides new evidence of the dramatic risks, for the central nervous system, linked to particulate pollution.