New Stanford study casts doubt on developmental potential of adult stem cells

September 05, 2002

STANFORD, Calif. - Researchers at Stanford University Medical Center report that they have tried - and failed - to coax adult blood-forming stem cells in mice into forming tissues other than blood and immune cells. This research, published in the Sept. 5 issue of Science Express, an advance online publication of the journal Science, strikes another blow at the idea that stem cells taken from adults have the same developmental potential as those taken from embryos.

This work contributes to a growing debate over the fate of embryonic stem cell research. Several researchers have claimed that stem cells taken from adult bone marrow have the same potential to form all adult tissues as do embryonic stem cells. With that in mind, some policy-makers want to ban embryonic stem cell research in favor of similar research using less controversial adult stem cells.

Irving Weissman, MD, the Karel and Avice Beekhuis Professor of Cancer Biology at Stanford and lead author of the current study, has long argued that only embryonic stem cells have the ability to form all adult tissues. The latest paper reinforces that view.

"This is the first time somebody injected a single adult stem cell and showed that it made only blood," said Weissman, who has served on committees to advise the federal and California governments about embryonic stem cell policies. He added that this research should teach other researchers and members of the lay community to wait for all the data before they rush to judgment. "Especially when you are jumping to a political judgment that has big policy repercussions," he added.

Weissman and postdoctoral fellow Amy Wagers, PhD, studied whether stem cells taken from adult mice could integrate into adult tissues. They first isolated adult blood-forming stem cells from the bone marrow of mice. These cells were engineered to make a green fluorescent protein that's visible under a microscope. The researchers then injected a single stem cell into mice whose bone marrow had been knocked out by irradiation. (Bone marrow produces all blood and immune cells.)

After several weeks, the green fluorescent stem cell had single-handedly repopulated the blood and immune cells of the mice. When the researchers searched through more than 15 million muscle, brain, liver, kidney, gut and lung cells, they found only one brain and seven liver cells that were green under the microscope, indicating that these cells were either formed from the adult stem cell or that one of the stem cell's progeny had fused with the original cell.

Weissman and Wagers said that even if these eight cells represent an adult stem cell developing into other tissue types, the level is so low that it wouldn't be useful as a therapy. "It's not to say that nobody should think about adult stem cell plasticity - of course people should look into it - but it's not as robust as it is claimed to be," Wagers said.

In another set of experiments, the researchers tested whether the single adult stem cell could replace intestinal cells when the intestine was destroyed by radiation. After several weeks new cells had grown to replace those that were lost, but none of the new cells was green under the microscope, meaning the cells did not come from the adult stem cell.

Wagers said this research, in conjunction with recent work from other labs that also failed to verify adult stem cell plasticity, should dim the enthusiasm for pursuing research only in adult stem cells. "I hope it tempers the enthusiasm for adult stem cell plasticity. Maybe it's not the answer that it appeared to be," she said.
Other Stanford researchers who contributed to this study are undergraduate student Richard Sherwood and graduate student Julie Christensen.

Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital at Stanford. For more information, please visit the Web site of the medical center's Office of Communication & Public Affairs at

Stanford University Medical Center

Related Stem Cells Articles from Brightsurf:

SUTD researchers create heart cells from stem cells using 3D printing
SUTD researchers 3D printed a micro-scaled physical device to demonstrate a new level of control in the directed differentiation of stem cells, enhancing the production of cardiomyocytes.

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.

Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.

New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.

NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.

Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.

Read More: Stem Cells News and Stem Cells Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to