Toxic particles once inhaled may travel direct to the brain, according to a study

Toxic particles once inhaled may travel direct to the brain, according to a study ...

Air pollution does not only affect your lungs and heart''s health. Recent research has found fine particulate matter may also cause brain damage, and scientists believe they''ve discovered how to avoid this phenomenon.

Ultra-fine particles in the air may enter the lungs, seep into the bloodstream, and eventually invade the brain, according to mouse models.

Once the toxins are present in neurological tissue, they are much harder for the immune system to clear. In fact, the authors found that airborne particles were retained in the brain for longer than any other organ in the mouse body.

If particles are sufficiently large enough, they may slip past the blood brain barrier, which is usually to prevent dangerous solutes and other harmful components in blood from reaching the central nervous system.

Before, a blood brain barrier was linked to cognitive damage, but the current research is one of the first to show air pollutants sneaking by the brain''s border patrol.

Scientists thought that fine particulate matter might not be able to reach the blood brain barrier before they made it to the brain via the nose or the nerve cells of the gut, which are directly connected to the central nervous system.

"This study opens new light on the relationship between inhaling particles and how they subsequently move around the body," says environmental nanoscientist Iseult Lynch of the University of Birmingham in the United Kingdom.

On the contrary, much more is known about how air pollution affects the cardiovascular system than the central nervous system.

Even in young people, chronic exposure to air pollution in major cities has been linked to neuroinflammation and cognitive decline. Several of the damage is eerily similar to Alzheimer''s disease, which is also linked to a blood brain barrier.

Researchers investigated the cerebrospinal fluid of 25 individuals exposed to chronic air pollution, and found evidence (in about one third of the group) of particles that are harmful air pollutants, including iron, calcium, potassium, and anatase titanium dioxide.

According to these findings, toxic air is infiltrateing the fluid that bathes our brains.

The researchers contacted mice in order to further test this idea.

The authors discovered that black carbon particles and titanium dioxide particles were injected directly into the lungs while bypassing the nose completely.

"Strikingly," the authors note, "the [blood brain barrier] structure was damaged," and this resulted in roughly 20% increase in leakage in several mouse brain tissue slices. Unusual contaminants were found inside and outside blood vessels near the blood brain barrier, which further reinforces security breakdown.

The authors show ultra-fine particles in a petri dish that they found in the blood brain.

Mouse who were not exposed to air pollutants showed no evidence of the harmful chemicals in their brain tissue.

After about a day, the authors discovered an exponential decrease in air pollutants from all the mouse bodies, but the brain was slower to excrete the contaminants.

"These findings, therefore, provide a line of evidence in proving the dangers of particulate pollution to the [central nervous system] and in elucidating the exposure path of exogenous particles from inhalation to the brain."

"To be sure that more direct evidence of the exposure and transportation of ambient fine particles from inhalation via the bloodstream and the damage of the [blood brain barrier] to the brain is needed in the near future, including epidemiological research."

The study was published in Proceedings of the National Academy of Sciences (link not yet exists at the time of publication).

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