January 23, 2009 / 7:28 PM / 11 years ago

Q+A-First human tests of embryonic stem cells

WASHINGTON, Jan 23 (Reuters) - The U.S. Food and Drug Administration has approved the first tests in human patients of embryonic stem cells, Geron Corp. (GERN.O) reported on Friday.

Here are some questions and answers about human embryonic stem cell research.

Q. What are embryonic stem cells?

A. These are cells found in days-old embryos that eventually repeatedly divide to become a complete embryo. When there are just a few of these cells, each one has the power to divide into any of the many different cell and tissue types in the body.

Q. Why are they controversial?

A. Opponents of human embryonic stem cell research, such as the Catholic Church, former president George W. Bush and some, but not all, conservatives believe that destroying a human embryo to harvest cells is immoral and unethical.

Q. Where did Geron get the cells it used?

A. They used embryos left over from in-vitro fertilization, or IVF, attempts. These frozen, unused embryos are typically thrown away.

Q. Isn’t using these cells illegal?

A. U.S. law forbids the use of federal funds to destroy human embryos. There are no U.S. restrictions on the use of private money to do this research. Some governments, such as Britain’s, actively encourage the research. Congress has been trying to lift the restrictions and President Barack Obama is expected to back such efforts soon.

Q. Aren’t there other stem cells that do not involve human embryos?

A. Stem cells can be found in blood, bone marrow and various tissues. But these cells have become partly differentiated, meaning they are on their way to becoming various tissues, and are not as flexible as embryonic cells.

Several teams of scientists have also discovered how to reprogram ordinary adult skin cells to behave like embryonic stem cells, but this technology is not well-developed and scientists say it is important to pursue all avenues of research.

Q. Why the excitement over stem cells?

A. Stem cells provide a new route to treatment. They can proliferate indefinitely, migrating to the “right” place in the body to repair injury caused by accidents or disease, taking up residence, growing new tissue there and even producing compounds that encourage other cells to grow.

The hope is they can replace brain cells destroyed in Parkinson’s disease, nerve cells destroyed by accidents or multiple sclerosis, and pancreatic cells destroyed by diabetes, for example.

Q. What is Geron going to do with them?

A. Geron has found a way to trick human embryonic stem cells into becoming immature oligodendrocytes, which protect nerve cells. If injected within a week or two of a spinal cord injury, they have restored the ability to walk in rats. Geron hopes to test then in eight to 10 human volunteers with recent spinal cord injuries.

If the method is shown to be safe, they can test the therapy in more people to see if it works.

Reporting by Maggie Fox, editing by Will Dunham

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