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Japanese researchers succeed in converting ES cells into neural tissue

June 05, 2006

Researchers at Japan's governmental research body Riken have succeeded in selectively converting ES cells into neural tissue by using human amniotic membrane.

The method to develop neural tissues without using cells taken from other animals, such as mice or cows, will enhance the safety of the derived tissues, taking the realization of regenerative medicine a step closer to reality.

"We believe that we are the first ones in the world to succeed in differentiating ES cells into targeted cells at high efficiency, using only substances derived from humans," said Yoshiki Sasai, head of the organogenesis and neurogenesis group at the Riken Center for Developmental Biology.

According to a report published online on the Proceedings of the National Academy of Sciences of the United States of America on Tuesday, Sasai and his team took off the epithelial layer, or the upper-most layer, of the human amniotic membrane, coated it with gelatin, and planted ES cells on it.

After two weeks, 90 percent of the ES cells differentiated into neural precursor cells. After four more weeks, about 40 pct of the neural precursor cells developed into neurons: among them were neurons that produce such neurotransmitters as dopamine and serotonin.

Dopamine-producing neurons can cure Parkinson''s disease, and serotonin-producing cells can help those suffering from depression and bipolar disorder.

Sasai and his team also succeeded in creating motor neurons from the derived neural precursors by adding a protein called Sonic hedgehog.

ES cells, or embryonic stem cells, are derived from internal cell mass formed during an early developmental stage of fertilized eggs. The pluripotent, self-renewing cells can theoretically develop into any tissue cells. But their clinical application had been difficult because they needed to be cultured with animal cells to differentiate into certain cells.

Sasai said his team hopes to carry out further research to apply the method to create tissues to treat such intractable diseases as amyotrophic lateral sclerosis.

Source: Jiji Press
Date: June 5th, 2006
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