BEIJING, Feb. 1 -- Chinese scientists working at an American university said they had coaxed motor neurons from human embryonic stem cells.

    

Zhang Suchun (Photo: Shenzhen Daily)

Zhang Suchun, a University of Wisconsin-Madison assistant professor of anatomy and neurology, and his student, Li Xuejun, published their study in the journal Nature Biotechnology on Sunday.

    The feat, which took more than two years of trial and error, is seen as an important step in the dream of creating spinal nerve cells in the laboratory to replace cells damaged by spinal cord injuries or by diseases such as amyotrophic lateral sclerosis, also called Lou Gehrig's disease.

    However, scientists cautioned that this therapy was still many years off. The more immediate impact of the research will likely be to provide a supply of motor nerve cells that can be used to test new drugs intended to treat various nerve ailments.

    "You can use this as a tool to figure out how to rescue cells," said Zhang Suchun.

    While there have been reports of scientists creating animal motor neurons, creating human motor cells has been difficult in part because of the complex nature of the cells.

    Most motor neurons emanate from the spinal cord, where they form long connections to muscles around the body. The connections, known as axons, can extend more than one meter.

    The researchers started with week-old embryonic stem cells, a type of master cell that is harvested a few days after conception and that can become any of the more than 200 cell types making up the human body.

    In their study, researchers first had to coax the embryonic stem cells to become a type of premature brain cell known as a neural stem cell. That entailed using a mix of hormones and growth factors, substances that nourish brain cells.

    "We used a cocktail to guide the embryonic stem cells to become neural stem cells," Zhang said. "It takes about two weeks."

    The neural stem cells were then allowed to develop into progenitor cells of motor neurons, which became actual motor neurons in a lab dish.

    "It's quite difficult," Zhang said. "We've been working on this for over two years."

    "These are the cells we would want for treatment of ALS," said Lucie Bruijn, science director and vice president of the ALS Association in the United States. "Things are moving very fast, and Zhang Suchun is making a real difference."

    ALS is a fatal disease that causes muscle weakness and, ultimately, paralysis. It destroys nerve cells in the brain and spinal cord. Gehrig, a New York Yankees star, died of the disease in 1941.

    (Source: Shenzhen Daily/Agencies)