What has concerned medics is how particles found in highly polluted areas, when inhaled into the lungs, affect blood vessels and the heart. Using an animal model researchers have demonstrated how inhaled nanoparticles travel from the lungs into the bloodstream. This draws a direct connected between air pollution and cardiovascular disease.
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Polluted air is full of nano- and microscopic-sized particles (and some of which are visible), of inorganic, organic and biological origin. Some particles are released directly from a specific source, while others form in complicated chemical reactions in the atmosphere. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.
Particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into the lungs. The World Health Organization considers such particles to be a major health issue and a leading cause of premature deaths. For some time scientists have suspected that very small, very fine particles traverse from the lungs and into the bloodstream. However, direct evidence for this had not been found. This has now changed thanks to new research by Dr. Mark Miller from the University of Edinburgh, Scotland, supported by additional studies undertaken at the National Institute for Public Health and the Environment in the Netherlands.
By using gold nanoparticles, which can be tracked using specialist technology, to simulate air pollution and using rodents, Dr. Miller was able to show how inhaled nano-sized particles enter the lungs and then, through osmotic action, enter the bloodstream. Further studies when then performed using volunteer human subjects. Here 14 healthy volunteers and 12 surgical patients inhaled gold nanoparticles. Within a few minutes the nanoparticles were detected in both the blood and urine. The research indicates that nanoparticles travel from the lungs into the bloodstream, reaching susceptible areas of the cardiovascular system. The risk here is of heart attack or stroke.
The research has been published in the journal ACS Nano. The research paper is titled “Inhaled Nanoparticles Accumulate at Sites of Vascular Disease.”