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Stem cell research Just the facts

January 29, 2007|by JULIE E. GREENE

Stem cell research is such a fast-moving field that even some experts have trouble keeping up with all of the research projects.

"A definitive answer you get one day might not be a definitive answer the next day," said Sean Tipton, president of the Coalition for the Advancement of Medical Research. CAMR is a coalition of groups that want to see embryonic stem cell research advance, he said.

Like many medical research topics, there is no apparent solitary group or agency that keeps track of all stem cell research.

With new stories, developments and political opinions almost every day, it's not difficult to become confused about what's going on with stem cells.

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Then there are claims and rumors of stem cell treatments available that haven't been approved yet by the Food and Drug Administration.

So here are the basic facts.

Stem cells are cells that aren't specialized; they don't have a specific job yet.

The hope is to find ways to stimulate them to become specific types of cells, such as a heart muscle, nerve or bone cells. If scientists are successful, these cells could be used to replace injured or deficient populations of cells, thereby treating or curing certain medical conditions, according to information from the National Institutes of Health.

There are other questions scientists must solve, including finding ways to transplant stem cells so they become a specific cell type and don't remain nonspecialized, said Tipton and Story Landis, an NIH expert on stem cells and director of the National Institute of Neurological Disorders and Stroke.

In some cases, nonspecialized cells could keep dividing and form a teratoma or tumor that could develop into cancer, Landis said.

The upside of stem cell research is that it might lead to cures for diseases such as Parkinson's and diabetes or treatments to repair spinal cord injury or regrow breast tissue for cancer survivors, experts said.

Stem cell research also is exciting because, if scientists can figure out how embryonic stem cells grow into specialized cells, it could help determine how cells become cancerous, Tipton said.

Types of stem cells

There are different types of stem cells such as embryonic, adult, amniotic and those found in umbilical cord blood.

The National Institutes of Health provide basic information about embryonic and adult stem cells online at http://stemcells.nih.gov.

Embryonic stem cells are derived from embryos that develop from eggs fertilized in vitro and later donated for research with the consent of the donors.

Landis said to her knowledge, no one had been treated in the U.S. with human embryonic stem cells.

Adult stem cells are undifferentiated cells found in certain tissues or organs such as bone marrow that can develop into the major cell types in those tissues or organs.

Adult stem cells that form blood cells have been used for decades with bone marrow transplants.

One advantage of embryonic stem cells is that they can develop into all cell types of the body, whereas adult stem cells usually are limited to becoming the cell types of the tissue they are found in. There is some research suggesting adult stem cells might be able to become other types of cells with artificial stimulation.

Another advantage with embryonic stem cells is it's easy to grow large numbers of them in a culture.

A possible plus for adult stem cells is that adults who had their own stem cells reintroduced to their bodies would not have the cells rejected by their immune systems.

Umbilical cord blood also contains stem cells that can be used in bone marrow transplants for people with blood-based malignancies such as leukemia, according to the FDA.

Several for-profit and not-for-profit companies are offering services to store a newborn's umbilical cord blood for potential future use. On Jan. 16, the FDA issued proposed guidelines to license such establishments.

Earlier this month, researchers at Wake Forest University and Harvard University reported finding stem cells in amniotic fluid and turning them into different tissue cell types, including brain, liver and bone cells, according to The Associated Press.

The controversy

The biggest controversy centers around human embryonic stem cells because many people believe a fertilized egg is a human being with rights and should be protected. These people don't want research performed on fertilized eggs or fetuses.

There are no approved treatments for people using human embryonic stem cells, Landis said. Research is still at the nonhuman animal experimental stage.

On Aug. 9, 2001, President Bush announced limits for federal funding for research using human embryonic stem cells. For example, federal funding can be used in research with embryonic stem cells in which the destruction of the embryo was initiated before 9 p.m. Aug. 9, 2001, if certain conditions were met.

There's still embryonic stem cell research going on with state and private funding, experts said.

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