Nanoparticles kill and maim blood vessel cells found in the human brain.

Oct 21, 2008

Chen, L, RA Yokel, B Hennig and M Toborek. 2008. Manufactured aluminum oxide nanoparticles decrease expression of tight junction proteins in brain vasculature. Journal of Neuroimmune Pharmacology doi:10.1007/s11481-008-9131-5y.

Synopsis by Stacey L. Harper

A study using cells and rats shows that nanoparticles of aluminum oxide can kill and adversely change the special cells that line the blood vessels in the human brain. The rapid increase in production and use of these very, very small particles will inevitably increase human exposure to the as yet unknown risks from these materials.

Nanoparticles of aluminum oxide can be toxic to cells that line the blood vessels in the human brain, a recent study with cells and rats finds. In 2005, aluminum oxide nanoparticles represented 20 percent of the world market production of nanoparticles. Increased production of these nanomaterials will inevitably increase human exposure.

This study was designed to determine the effects of nano-alumina, particles of aluminum oxide only nanometers in diameter, on the human blood-brain barrier. Cells that line the inside of blood vessels in the brain were treated with nano-alumina, normal size alumina particles, carbon nanoparticles or carbon not converted to nanoparticles. After exposure, researchers assessed cell structure and death and the effects on mitochondria and tight junction proteins, critical proteins that tightly connect the cells lining the blood vessels. In addition, rats received an intravenous dose of nano-alumina.

The nanoscale versions of alumina and carbon were significantly more toxic than their respective compounds of normal particle size. Both nano-alumina and nano-carbon increased cell death and disrupted mitochondrial function whereas alumina and carbon did not. Nano-alumina also disfigured cells, significantly increased cellular oxidative stress and disrupted the expression of tight junction proteins. Animal experiments confirmed the alteration in proteins with a loss of critical proteins in the cerebral blood vessels in rats.

Aluminum oxide is one of the versatile ceramic oxides with diverse applications in the electrical, engineering and biomedical fields. Now, nanoparticles of aluminum oxide are being manufactured due to the properties that are enhanced when its size is reduced to such a small scale.  Additional findings from this study indicate that antioxidants may be applied as a counter-treatment to nanoparticle toxicity.