Stem cells change and grow in mice
'Immortal' cells from human embryos now rodent brains
Margaret Munro
National Post
Immortal cells, grown from left-over human embryos, have taken on new life in mouse brains.
The human cells, in one case half a million of them, developed into brain cells that thrived in the rodents, two research teams report in the December issue of Nature Biotechnology.
"This is a very important step. The cells work," says Professor Su-Chun Zhang, of the University of Wisconsin-Madison, lead author of one of the reports that raise hope that embryonic cells will be able to repair spinal cords and reverse neurological diseases.
The cells implanted into the mice were grown from the "immortal" stem cells that Wisconsin researchers created from the left-over human embryos in 1998,setting off an ethical and political storm.
It is believed the stem cells, which the scientists have patented and are now marketing to other researchers, can be coaxed to grow into any tissue in the human body.
The mouse experiments show they can grow into neurons, and attest to the cells' enormous potential, say Prof. Zhang and his colleagues.
The cells promise, they say, to generate an inexhaustible source of transplantable neural cells and tissue to repair everything from spinal cord injuries to the ravages of Parkinson's disease.
Others are more circumspect. "The ability to specifically control the development of embryonic stem cells into brain cells is an important step forward; however, further studies are needed to determine whether these brain cells are functional," Nature Biotechnology cautions in a notice to reporters.
Many scientists and ethicists say it may not be necessary to exploit embryonic stem cells because there is evidence that stem cells lurking in adult skin and blood can also be coaxed to grow into replacement parts and tissues. But the new studies are seen as a big step forward for the proponents of the use of embryonic stem cells.
The Wisconsin team and a second group in Israel and Australia report similar findings. Both teams grew human embryonic cells in the lab and exposed themto growth factors to turn them into brain cell precursors.
The cells -- up to half-a-million of them -- were then transplanted intothe brains of newborn mice and left to follow developmental cues inside the animals. The cells differentiated into neurons and astrocytes, the cell species that populate the different regions of the brain and spinal cord.
"These transplanted cells had no experience in the brain, and we wanted to see if they would mirror the development of the mouse brain," Prof. Zhang says.
"And they do."
The cells are " almost identical to what the neuron should be in the healthy brain," he says. "These are the cells that will be used, ultimately, to treat Parkinson's and other central nervous system disorders."
Prof. Zhang stresses it will be years before the cells could be used on people. "We are no where near clinical application," he said.
Earlier this year, a team of Montreal researchers reported finding more accessible -- and much less controversial -- stem cells lurking in the skin that may be able to morph into neurons, and also bone, muscle, blood and other kinds of cells.
The discovery, reported in Nature Cell Biology by Freda Miller and her colleagues at the Montreal Neurological Institute, might also lead to cures for Parkinson's disease, diabetes and other degenerative illnesses by providing new cells to replace damaged or dead ones. For example, a patient who has a spinal cord injury, would have skins cells harvested that would grow new neurons to treat the spinal injury.
The Montreal team is now working to determine whether or not the cells can grow into neurons that can cure rodents with an animal versions of Parkinson's disease and other disorders.