Motor Neurons Grown From Stem Cells

HuckleB

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Mon Jan-31-05 12:48 AM
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Motor Neurons Grown From Stem Cells

http://www.scienceagogo.com/news/20050030232521data_trunc_sys.shtml

"After much trial and error, scientists have coaxed human embryonic stem cells into becoming spinal motor neurons, the critical nervous system pathways that relay messages from the brain to the rest of the body. The findings, reported in the journal Nature, are important because they provide guidance for scientists trying to repair damaged or diseased nervous systems.

Motor neurons transmit messages from the brain and spinal cord, dictating almost every movement in the body from the wiggling of a toe to the rolling of an eyeball. The new development could one day help victims of spinal-cord injuries, or pave the way for novel treatments of degenerative diseases such as Lou Gehrig's disease. With healthy cells grown in the lab, scientists could, in theory, replace dying motor neurons to restore function and alleviate the symptoms of disease or injury. Much closer to reality, the advance will allow researchers to create motor neuron modeling systems to screen new drugs, says study leader Su-Chun Zhang at the University of Wisconsin-Madison.

Scientists have long believed in the therapeutic promise of embryonic stem cells with their ability to replicate indefinitely and develop into any of the 220 different types of cells and tissues in the body. But researchers have struggled to convert blank-slate embryonic stem cells into motor neurons. The goal proved elusive even in simpler vertebrates such as mice, whose embryonic stem cells have been available to scientists for decades. One reason scientists have had difficulty making motor neurons, Zhang believes, may be that they are one of the earliest neural structures to emerge in a developing embryo. With the ticking clock of development in mind, Zhang and his team deduced that there is only a thin sliver of time - roughly the third and fourth week of human development - in which stem cells could be successfully prodded to transform themselves into spinal motor neurons.

In addition to the narrow time frame, it was also critical to expose the growing stem cells to an array of complex chemical cocktails. The cocktails constitute naturally secreted chemicals - a mix of growth factors and hormones - that provide the exact growing conditions needed to steer the cells down the correct developmental pathway. "You need to teach the embryonic stem cells to change step by step, where each step has different conditions and a strict window of time," said Zhang. "Otherwise, it just won't work."

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Other links on this story:

Fresh hope for spinal injury victims:
http://www.theherald.co.uk/news/32473.html

A Recipe for Motor Neurons:
http://www.washingtonpost.com/wp-dyn/articles/A50111-2005Jan30.html

Scientists Switch Stem Cells into Neurons:
http://www.sciam.com/article.cfm?chanID=sa003&articleID=00048F8A-C91A-11FA-891A83414B7F0000