Scientists Watch Cells' Duplication for the First Time

Researchers at the University of Florida have been able to get mouse brain cells to duplicate in a lab dish for the first time, increasing the odds that they may one day be able to do the same with human cells.

Writing in the latest issue of the Proceedings of the National Academy of Sciences, the brain experts say their cell culture method offers the promise of producing a limitless supply of a person's own brain cells to treat illnesses ranging from Parkinson's and Alzheimer's disease to epilepsy.

"It's like an assembly line to manufacture and increase the number of brain cells," said Bjorn Scheffler, a neuroscientist at the University of Florida, who took part in the project.

While it was once thought that the brain lost the ability to make new cells in infancy, scientists now know the brain continues to produce small amounts of new cells throughout life. But this natural replenishment is not enough to overcome disease or trauma or even the normal wear-and-tear of aging.

The new technique picks up where nature stops, harnessing the same immature brain stem cells that can differentiate into various types of specialized brain cells, but in far greater numbers because development takes place outside the brain. It also advances understanding of stem cells in the brain by identifying the critical master cells.

While the general location of the cells had been known, no one had been able to positively identify and manipulate them.

"We've isolated for the first time what appears to be the true candidate stem cell," said Dennis Steindler, executive director of the university's McKnight Brain Institute and senior author of the report.

"There have been other candidates, but in this case we used a special microscope that allows us to watch living cells over long periods of time ... so we've actually witnessed the stem cell give rise to new neurons. Possibly, a different method may come up to identify the mother of all stem cells, but we're confident this is it," Steindler said.

In humans, stem cells develop naturally into full-fledged brain cells as they travel from deep within the brain to mature as neurons when they reach a structure called the olfactory bulb.

This natural development of stem cells in the brain is similar to the way bone marrow produces blood cells throughout a person's life, a process called hematopoiesis. Steindler's team noticed the similarities in the late 1990s.

In the mouse experiments, scientists collected the stem cells from mice and used chemicals to induce them to differentiate. The cells still move around, but don't seem to need the environment of the brain to mature.

"We are actually using methods that researchers involved in hematopoiesis used," Scheffler said. "We can basically take these cells and freeze them until we need them. Then we thaw them."

BRAIN STEM CELLS

Scientists have known for some time that the brain has stem cells that duplicate modest numbers of new cells throughout life. Now, researchers at the University of Florida have found a system that allows them to harvest brain stem cells in mice and multiply them rapidly in the lab, raising the promise of a limitless supply of customized brain cells to treat disease or trauma.

"It's like an assembly line to manufacture and increase the number of brain cells," said Bjorn Scheffler, neuroscientist, University of Florida.