Inhaled Nanoparticles Take a Direct Route to Brain

The US State Department (of all places!) is reporting about a study from University of Rochester Medical Center that has shown that some nano-sized materials have an efficient uptake and distribution into the central nervous system, raising further fears of health effects of nanotech.
From the Foggy Bottom press release:

The researchers examined nanoparticles from a chemical compound called manganese oxide, which is prevalent in welding fumes. They tested the nanoparticles at a concentration typically inhaled by factory welders.
“The main reason for studying manganese oxide,” said lead author Alison Elder, research assistant professor of environmental medicine at Rochester, “is that welders as a group have an increased incidence of Parkinson-like symptoms earlier in life than people with genetically controlled Parkinson’s disease, so that was an intriguing finding…”
Results from other materials the researchers studied showed that particles of less than 100 nanometers could get into the brain, Elder said. “This study was conducted to investigate a little more thoroughly the mechanism by which those particles get into the brain.”
In the study, the researchers saw changes in gene expression that could signal inflammation and a cellular stress response in the brain, but they do not yet know if a buildup of nanoparticles causes brain damage.
The naturally occurring nanoparticles used in the study were the same size as manufactured nanoparticles, the key ingredients in a growing nanotechnology industry. The industry is controversial because it expands while investigations about health and safety concerns are still under way…
In the Rochester Medical Center study, the particles passed quickly through the rats’ nostrils to the olfactory bulb, a part of the brain near the nasal cavity. They settled in the lungs and in parts of the brain.
“There are differences in nasal structure between human and rat, and olfactory bulb structure between human and rat,” Elder said, “but despite those differences, it’s likely that this pathway of exposure is operative in both species.”
After 12 days, the concentration of particles in the rats olfactory bulbs rose 3.5-fold, doubled in the lungs and showed small but significant increases in other brain regions, including the cerebellum, frontal cortex and striatum.
The meaning of the particles’ presence in the brain will not be clear until the affected brain cells can be examined, Elder added, a process that is not within the scope of the current study.

The press release…
More from University of Rochester Medical Center…