stem cells
Andre Penner/AP
A researcher holds a test tube filled
with stem cells.

Chinese Scientists Make Breakthrough in Study of Non-Embryonic Stem Cells

July 24, 2009 02:00 PM
by Denis Cummings
Two independent studies found that mice can be produced using pluripotent cells derived from adult cells, raising hopes these cells could serve as an alternative to embryonic cells in stem cell research.

Mice Created Using Non-Embryonic Cells

Two separate teams of Chinese scientists have revealed that they successfully produced living mice from stem cells taken from connective tissue. These cells were reprogrammed into embryonic-like cells called induced pluripotent stem cells, or iPS cells.

The studies, which were published Thursday in journals Nature and Cell Stem Cell, demonstrate that iPS cells, which were first developed in 2006, have the ability to transform any type of tissue in the body.

The development moves scientists closer to one day using iPS cells in studying human illnesses, making the need for human embryonic stem cells unnecessary. In an e-mail to The Associated Press, Fanyi Zeng, co-author of the study in Nature, said that iPS cells could help doctors “understand the root causes of disease and lead to viable treatments and cures of human afflictions,” but cautioned, “There's a lot more (to do) before we can even mention humans.”

Background: Advances in the creation of iPS cells

The research builds on work by Shinya Yamanaka of Kyoto University, who in 2006 was the first to discover that mouse skin cells could be transformed into embryonic-like cells by ferrying four genes into the skin cell. In November 2007, a team led by Yamanaka and a separate team in Wisconsin each created iPS cells from human skin cells using genetically modified viruses.

Though the process was effective in creating iPS cells, it was very dangerous because the retroviruses could integrate their genes into the new cells’ DNA and cause cancer in patients. The process was improved in September 2008, when scientists created iPS cells using an adenovirus, which does not integrate its DNA into cells.

In March, British and Canadian researchers published a study revealing that they could create cells without using viruses through a trick called “piggyBac.” Bloomberg reported, “After triggering the cells to transform, the genes vanished without a trace, and with them went the risk that they could trigger cancer.”

Opinion & Analysis: Stem cell debate

Embryonic cells are considered the most valuable stem cells because they are able to become any of the over 200 types of tissue in the human body. There are, however, many ethical and moral concerns over the use of embryonic cells, which require that a fertilized egg be destroyed.

Former President George W. Bush imposed strict restrictions on the use of embryonic stem cell research in 2001. President Barack Obama overturned Bush’s restrictions in March, opening up new lines of embryonic cells to researchers.

Though embryonic stem cells have the potential to cure a wide range of diseases and conditions, scientists have not yet tested embryonic stem cell therapy on humans. In January, the FDA granted approval to biotech company Geron to conduct a clinical trial using embryonic stem cells, which are scheduled to begin this summer.
To learn more about the debate on stem cell research, read the findingDulcinea Web Guide to Stem Cells.
Opponents of embryonic stem cell research argue that, with the most recent advances in the creation of iPS cells, it is no longer necessary to use embryonic cells. “Nobody has been able to find anything that embryonic stem cells can do that these cells can't do, said Richard M. Doerflinger of the U.S. Conference of Catholic Bishops to The Washington Post. “This was the last remaining barrier.”

However, further study is required before scientists can even think about using iPS in human research. “This very exciting paper proves that some iPS cells can perform like embryonic stem cells in making a whole mouse from cells in a Petri dish,” said Dr. George Daley of the Children's Hospital and the Dana-Farber Cancer Institute in Boston. “This does not prove that all iPS cells can do this.”

Most Recent Beyond The Headlines