Jewish World Review Feb. 26, 2003 / 24 Adar I, 5763

Creating stem cells from blood

By Steve Mitchell | (UPI) Scientists said that they have for the first time discovered adult stem cells originating in the blood, a finding that could lead to an easily accessible source of cells to treat diseases.

Adult stem cells have the ability to become other cells and tissue types in the body and thus have the potential to replace cells damaged by disease. Such stem cells also are found in the bone marrow but they can be difficult to obtain and some studies suggest they might not have the ability to turn into other tissue types.

Scientists at the Biochip Technology Center at Argonne National Laboratory set out to find another source of these cells and made the surprising discovery that certain components of the blood had these properties, Eliezer Huberman, a cell biologist and principal author of the study, told United Press International.

Using human blood, Huberman's team found that a subtype of immune system cells called monocytes could be coaxed into becoming other cell types. The findings appear in the Feb. 24 online version of the Proceedings of the National Academy of Sciences.

Although monocytes were known to exist, "it was not known that (there was a subtype) behaving like a stem cell" and capable of becoming other cell types, Huberman said.

The reason the monocyte stem cells went undetected is that in order for them to behave like stem cells a substance called a growth factor must be added to them. Growth factors direct the growth of cells and can determine the type of tissue into which a stem cell can develop.

The cells "are pretty rare ... but they can be expanded very easily," he said. The technique is "very simple," and many laboratories will be able to use it and move this field forward, he said.

Adding various growth factors, Huberman's group was able to get the monocyte stem cells to express markers that indicated they had become brain cells, liver cells and skin cells. They also succeeded in getting the stem cells to transform into cells of the immune system and cells lining blood vessels, he said.

The work was done in test tubes so at this point it is not known if these different cell types are functional or will ever prove useful for treating disease.

Huberman said that is his team's next step. The researchers plan to do studies with mice blood to see if the cells can turn into functional tissue inside the body.

The advantage of the monocyte stem cells over bone marrow adult stem cells is they are "easily available and accessible," Huberman said. Obtaining stem cells from bone marrow "is to some degree a painful procedure," he said, but obtaining the monocyte cells would only require drawing blood.

In addition, the monocyte cells can be frozen and still retain their vitality. This indicates the cells could be obtained from frozen blood and used to treat patients. "If an individual donates blood, we can freeze it and later isolate these stem cells and hopefully use it in the future to help people," he said.

Nelson Chao, a hematologist and director of the bone marrow transplant and stem cell transplant program at Duke University in Durham, N.C., called the finding remarkable.

"People have been looking at these cells for a hundred years, so it's surprising that a monocyte-like cell can give rise to these other tissues," Chao told UPI.

However, he noted, "There's no proof that these cells really are what they think they are ... There's no demonstration that they can function as a tissue," he said. That will require further studies, such as the mouse study Huberman plans to do, Chao said.

Appreciate this type of reporting? Why not sign-up for the daily JWR update. It's free. Just click here.

Comment by clicking here.


© 2002, United Press International