A scientist looks through a microscope.
(photo credit: INGIMAGE)
Inhaled nanoparticles of silicon dioxide – such as those to which laboratory and manufacturing workers are exposed – raise the risk of heart disease, Technion-led research shows.
Nanoparticle products will have a world market of $3 trillion by the year 2020, it is estimated.
Nanoparticles – extremely tiny particles measured in billionths of a meter – are increasingly common in the environment, and especially in biomedical products. Their toxicity has been researched in general terms, but a team of Israeli scientists has for the first time found that exposure nanoparticles of silicon dioxide (SiO2) can play a major role in the development of cardiovascular diseases when the NP cross tissue and cellular barriers and also find their way into the circulatory system.
Their study, published in the December issue of Environmental Toxicology, was published online in the journal on Wednesday.
The research team was composed of scientists from the Israel Institute of Technology- Technion’s Rappaport Faculty of Medicine, the Rambam Medical Center and the Center of Excellence in Exposure Science and Environmental Health.
“Environmental exposure to nanoparticles is becoming unavoidable due to the rapid expansion of nanotechnology,” said the study’s lead author, Prof. Michael Aviram, of the medical faculty. “This exposure may be especially chronic for those employed in research laboratories and in hi-tech industry where workers handle, manufacture, use and dispose of nanoparticles.
Products that use silica-based nanoparticles for biomedical uses – such as various chips, drug or gene delivery and tracking, imaging, ultrasound therapy, and diagnostics – may also pose an increased cardiovascular risk for consumers as well.”
In this study, researchers exposed cultured laboratory mouse cells resembling the arterial wall cells to nanoparticles of silicon dioxide and investigated the effects. SiO2 particles are toxic and have significant adverse effects on macrophages, a type of white blood cell that takes up lipids, leading to atherosclerotic lesion development and its subsequent illness such as heart attack or stroke. The macrophages accumulate along the walls of the arteries, and high cholesterol, triglycerides and oxidative stress speed up atherosclerosis development.
“Macrophage cells accumulation in the arterial wall are a key cell type in the development of atherosclerosis, which is an inflammatory disease,” co-author Dr. Lauren Petrick said. “The aims of our study were to gain additional insight into the cardiovascular risk associated with silicon dioxide nanoparticle exposure and discover the mechanisms behind Si02’s induced atherogenic effects on macrophages.
We also wanted to use nanoparticles as a model for ultra-fine particle (UFP) exposure as cardiovascular disease risk factors.”
Both nanoparticles and UFPs can be inhaled and trigger negative biological effects.
Until this study, however, their effect on the development of atherosclerosis was largely unknown. Here, researchers have discovered for the first time that the toxicity of silicon dioxide nanoparticles has a “significant and substantial effect on the accumulation of triglycerides in the macrophages.”
A recent update from the American Heart Association also suggested that “fine particles” in air pollution leads to elevated risk for cardiovascular diseases. More research was needed, however, to examine the role of “ultra-fine particles” (which are much smaller than “fine particles”) on atherosclerosis development and cardiovascular risk.