It's like pulling a rabbit out of a hat. Researchers have reached inside the brain of a rat and pulled out neural stem cells – without harming the animal.
Since the technique uses nanoparticles already approved for use in humans, it is hoped that it could be used to extract neural stem cells (NSCs) from people to treat conditions like Parkinson's, Huntington's and multiple sclerosis.
Extracting NSCs from the person who needs them would avoid immune rejection – but they are difficult to remove safely. So Edman Tsang at the University of Oxford and his colleagues have developed a technique to safely fish out NSCs that originate in cavities in the brain called ventricles.
Tsang's team coated magnetic nanoparticles with antibodies that bond tightly to a protein found on the surface of NSCs. They then injected the nanoparticles into the lateral ventricles of rats' brains. Six hours later, after the nanoparticles had bonded to the NSCs, the researchers used a magnetic field around the rats' heads to pull the stem cells together. They could then be sucked out of the brain with a syringe.
No ill effects
After freeing the stem cells from the nanoparticles, the team found they could grow them in a dish, suggesting they were undamaged by the process. The rats, meanwhile, were back on their feet within hours of the surgery, showing no ill effects.
"Harmlessly extracting neural stem cells from the living mammalian brain is an advancement," says Gianvito Martino, a neural stem cell researcher at the San Raffaele Hospital in Milan, Italy. But he cautions that the extracted cells must be tested further before we can say for sure that Tsang's team has achieved the feat. "To be sure that we are dealing with real NSC-derived neurons electrophysiological testing is required," he says.
There might also be problems applying the technique to people, says Martino. The evidence suggests that human NSCs are both less abundant and less active than rodent NSCs. This means there may be fewer around to extract from the human brain, and those that are extracted may be difficult to coax into growing.
Martino thinks there might be easier ways to generate NSCs – for instance, by turning skin cells into induced stem cells, and then encouraging them to become NSCs.
Journal reference: Angewandte Chemie International, DOI: 10.1002/anie.201305482
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