Sep. 17, 2006 The promise of regenerative medicine and the nanotechnology catapulting it into the forefront of chemistry are highlighted in two papers presented on Monday, Sept. 11, in San Francisco during the American Chemical Society's 232nd national meeting.
Nanotubes help adult stem cells morph into neurons in brain-damaged rats
Carbon nanotubes - 80,000 times thinner than a human hair - enhance the ability of adult stem cells to differentiate into healthy neurons in stroke-damaged rat brains, according to American and South Korean researchers.
Thomas Webster, Ph.D., of Brown University in Providence, R.I, and colleagues at Yonsei University in Seoul mixed nanotubes with adult rat stem cells and then implanted the mixture into brain-damaged areas of three rats that had suffered strokes. In six other rats that had strokes, they implanted either adult stem cells or nanotubes - but not both - into brain-damaged areas.
After following the animals for up to eight weeks, the researchers concluded that neither nanotubes nor adult stem cells alone triggered regeneration or repair in the brain-damaged regions. In fact, when used alone, adult stem cells migrated to healthy areas of the brain. But when combined with nanotubes, adult stem cells not only remained in the brain-damaged regions, they began to differentiate into functioning neurons. The finding could have important implications for the treatment of Alzheimer's, Parkinson's disease and other neurological disorders, Webster says.
Nanostructures promote formation of blood vessels, bolster cardiovascular function after heart attack
Injecting nanoparticles into the hearts of mice that suffered heart attacks helped restore cardiovascular function in these animals, according to Samuel Stupp, Ph.D., chemist and director of the Institute of Bionanotechnology in Medicine at Northwestern University in Evanston, Ill.
The finding is an important research advance that one day could help rapidly restore cardiovascular function in people who have heart disease, Stupp says. The self-assembling nanoparticles - made from naturally occurring polysaccharides and molecules known as peptide amphiphiles - boost chemical signals to nearby cells that induce formation of new blood vessels and this may be the mechanism through which they restore cardiovascular function. One month later, the hearts of the treated mice were capable of contracting and pumping blood almost as well as healthy mice.
In contrast, the hearts of untreated mice contracted about 50 percent less than normal. In other recent studies using a similar technique, Stupp and his colleagues found nanoparticles hastened wound healing in rabbits and, after islet transplantation, cured diabetes in mice. Nanoparticles with other chemical compositions accelerate bone repair in rats and promote the growth of neurons in mice and rats with spinal cord injuries, he says.
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