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Nanoparticles offer hope for frayed nerves(New Scientist Via Thomson Dialog NewsEdge) NANOPARTICLES have had a bad rap lately over fears about their toxicity. Now, though, it seems the particles also have a kinder side. Cerium oxide nanoparticles have been shown to protect nerve cells from damage and so might one day be used to treat patients with spinal injuries or stroke. When the spinal cord is damaged, or part of the brain is starved of oxygen, the initial injury soon escalates and neighbouring cells begin to die. Many fall victim to oxidative damage from free radicals, which are released as the immune system goes into inflammatory overdrive to clear up the mess. Last year, a team led by neurobiologist David Schubert of the Salk Institute for Biological Studies in La Jolla, California, showed that cerium oxide nanoparticles can protect cultures of mouse brain cells from oxidative damage (Biochemical and Biophysical Research Communications , vol 342, p 86). The researchers also found that the particles themselves were not toxic to the cells. Now James Hickman and his colleagues at the University of Central Florida in Orlando have shown the nanoparticles can also protect spinal neurons. They tested similar particles, less then 5 nanometres in diameter, on cultures grown from neurons taken from the spinal cords of adult rats. The particles were able to protect the spinal neurons from hydrogen peroxide, a powerful oxidising agent (Biomaterials , DOI: 10.1016/j.biomaterials.2006.11.036). The researchers found that in exerting its antioxidant effect, cerium is itself oxidised from a 3+ to a 4+ state, but reverts back over time, which means that a small dose of nanoparticles can keep working for weeks at a time. "If you can confine it to the site of injury," says Hickman, "you should be able to have a long-lasting neuroprotective effect." Schubert adds that the nanoparticles seem to be taken up into nerve cells at the synapses, the junctions across which cells communicate with one another. This may give cerium oxide particles an advantage over other, more powerful, antioxidants that do not enter neurons in this way. "In general, the antioxidant approach is a good one, and this is an elegant way of doing that," says Ravi Bellamkonda of the Laboratory for Neuroengineering in Atlanta, Georgia, which is run jointly by the Georgia Institute of Technology and Emory University. However, Bellamkonda warns that the work is still at an early stage. The next test will be in demonstrating that the nanoparticles show similar neuroprotective benefits in live animals. Copyright 2007 Reed Business Information - UK. All Rights Reserved. |