Air is polluted by small particles associated with cardiovascular disease, which can result in premature death. However, it still remains a mystery as to how particles inhaled into the lungs can affect blood vessels and the heart.
Scientists have recently discovered evidence in animal and human studies that inhaled nanoparticles can in fact travel from the lungs and enter the bloodstream, potentially explaining the connection between cardiovascular disease and air pollution. The outcomes have been published in the journal ACS Nano.
According to estimations made by the World Health Organization, in 2012, almost 72% of premature deaths related to outdoor air pollution were due to strokes and ischemic heart disease. The remaining 28% was related to lung cancer, respiratory infections and pulmonary disease. A number of scientists have suspected that fine particles pass from the lungs into the bloodstream, but it has indeed been a challenging task to collect evidence supporting this assumption in humans. Thus, in order to track the fate of inhaled gold nanoparticles, Mark Miller and colleagues at the University of Edinburgh in the United Kingdom and the National Institute for Public Health and the Environment in the Netherlands used a selection of specialized techniques.
In the new study, 12 surgical patients, 14 healthy volunteers and several mouse models inhaled gold nanoparticles, which have been safely used in drug delivery and medical imaging. The nanoparticles were detected in urine and blood immediately after exposure. The nanoparticles appeared to preferentially gather at inflamed vascular sites, including carotid plaques in patients at risk of a stroke. The findings reveal that nanoparticles can from the lungs into the bloodstream and get into susceptible areas of the cardiovascular system where these nanoparticles could possibly increase the chances of a stroke or a heart attack, the researchers say.