Flow cytometry method sorts brain cells for potential transplants

University of Florida (UF; Gainesville, FL) scientists have discovered a method to separate necessary neurons during the process of generating brain cells for potential patient therapies, such as stem cell treatments for Parkinson’s disease, spinal cord injuries and other brain disorders. Flow cytometry, a method that counts and separates cells, could make it possible to deliver the necessary neurons to patients, without including vast amounts of other types of unnecessary brain cells.

“We need to be able to deliver precise doses of our therapeutic drug, which in this case is neurons that are needed to restore function lost as a result of disease or injury,” said Brent A. Reynolds, a professor of neurosurgery with UF’s Evelyn F. and William L. McKnight Brain Institute. “Prior to the development of our technology, it was not possible to deliver highly pure populations of neurons, or to control the number of neurons that were delivered.”

Experimenting with neural stem cells from rodents, the UF scientists and colleagues from the Queensland Brain Institute at the University of Queensland (Brisbane, Australia) were able to generate hearty, immature cells fully committed to becoming neurons, making it possible to provide unlimited quantities of neurons from a safe, renewable source of cells for replacement therapies in the central nervous system.

In doing so, the UF scientists discovered that size does matter when it comes to isolating the different cell types. After noticing that neurons are small and appear in clusters that rest on top of a layer of other, larger brain cells, the scientists turned to flow cytometry. By suspending neural stem cell-progeny—or offspring—in a tissue culture medium and running it through the cytometer, the scientists could efficiently select and separate the neurons from the other, less desirable brain cells, solely based on their unique size and internal composition.

Flow cytometry allowed the scientists to set parameters for cell size and internal characteristics, as well as easily sort two different cell populations, says Hassan Azari, a post-doctoral research associate of neurosurgery at UF. It also enables isolation of large quantities of purified neurons to use as a donor source for cell replacement strategies to treat disorders such as Huntington’s disease, spinal cord injury and Parkinson’s disease, he says.

Clinical trials have begun for transplantation therapies using neural stem cells, with about a half-dozen groups around the world testing them for safety and efficiency, says Reynolds.

The method was recently published in the online journal PLoS ONE, and the Australian National Health and Medical Research Council, the Overstreet Foundation, the Florida Brain and Spinal Cord Injury Trust Fund, and the National Institutes of Health supported the work.

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Posted by Lee Mather

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