With a serendipitous start, Argonne biologists have found a source of pluripotent stem cells that is as close as the human blood stream.

Previously believed to be found only in bone marrow, which is difficult to collect, and embryonic cells, which raise ethical concerns, these flexible stem cells are rare. But with Argonne’s findings, published in the Proceedings of the National Academy of Sciences, stem cells may soon be plentiful and easy to harvest.

These cells are termed pluripotent because they can morph into many specific body tissue cells. Scientists and doctors need these cells to study and treat diseases from cancer to Alzheimer’s. Patients with spinal cord injuries, Parkinson’s disease, stroke and heart disease may also benefit.

Currently, doctors use donated organs and tissues to replace destroyed tissues, but donor demand exceeds supply. If they were more readily available, pluripotent stem cells would be a renewable source of replacement cells to treat diseases because they can be manipulated into forming cells with specific functions.

Serendipitous stem cells
The scarcity of these cells may no longer be a problem. Eliezer Huberman, group leader of gene expression at Argonne’s Biochip Technology Center, showed that monocytes—immature white blood cells that are precursors to infection- fighting cells called macrophages—found in the bloodstream can form pluripotent stem cells.

Huberman, David Glesne, a cell biologist, and Yong Zhao, a postdoctorate fellow, were studying the differentiation of monocytes into macrophages when an illness kept them from attending the cultures.

While trying to salvage any remaining cells “we found that some of the surviving cells had morphed into cells that were different than macrophages,” said Huberman. “For example, a few had the appearance of blood vessel cells, and others of nerve cells.”

The biologists systematically experimented with monocytes to verify the accidental finding. The resulting cells displayed elevated levels of a blood- cell-forming marker, indicating they were blood stem cells.

To prove this, the researchers applied various growth factors, inducing the cells to grow into skin, liver, blood vessel and nerve cells. Next, researchers will inject these cells into animals to confirm that these cells have assumed the new functions.

Huberman says he hopes to extend his research to induce cells to differentiate into insulin-producing cells, which could treat diabetes, and neuronal cells that might treat neurological disorders. “Our procedure is simple, so that many labs will be able to repeat and extend the experiments, and as such, I hope it will mean progress in the use of our type of stem cells to study human diseases,” Huberman said.

Also see: www.anl.gov/Media_Center/logos21-2/stem01.htm.

For more information, please contact Evelyn Brown.

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