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MU scientists successfully convert pig tissue into stem cells

Sunday, July 5, 2009 | 12:01 a.m. CDT
Toshihiko Ezashi — lead investigator on the stem cell research team of R. Michael Roberts, MU curator's professor of molecular biochemistry in the animal sciences division — examines a cell culture inside the biological safety cabinet. Ezashi said that the team can spend up to 12 hours at a time in their lab.

COLUMBIA — Stem cell research has been considered by some to be the next area in science that could potentially produce life-saving cures, but controversy over the issue has limited research opportunities.

An MU researcher thinks he has found a way to avoid the controversy altogether.

R. Michael Roberts, curator's professor of molecular biochemistry in MU's animal sciences division and a member of the National Academy of Sciences, is the head of an MU research team that has successfully created stem cells that "think" they are embryonic stem cells. The new cells are called induced pluripotent stem cells and are created from the cells of pigs' connective tissue. The group’s findings were published Tuesday in the serial Proceedings of the National Academy of Sciences.

The induced stem cells are very similar in appearance and behavior to embryonic stem cells from humans and mice and, like embryonic stem cells, have the potential to be converted into all the various types of tissue cells in the body. Roberts said the induced stem cells could then be used clinically as a substitute for embryonic stem cells for grafting particular types of tissue into pigs and then testing the safety of stem cell therapies before they are performed on humans.

Induced stem cells have many advantages over cells taken from embryos, Roberts said. For one, they allow researchers to avoid the controversial procedures utilized in the gathering of embryonic stem cells, he said; the method for creating induced stem cells does not involve cloning and does not utilize embryos.

"You may be able to get stem cells that way," Roberts said, referring to the embryonic stem cell procedure. "But the procedure scares the heck out of people because it is a form of cloning."

Other researchers agree that the new procedure has the potential to advance stem cell science.

"It has been hard to derive stem cells from pig embryos," said Lawrence S.B. Goldstein, a genetics researcher and professor of cellular and molecular medicine at the University of California, San Diego School of Medicine. "And so this is an important step forward because they bypass this barrier by making these reprogrammed cells."

Charles E. Murry, director of the Center for Cardiovascular Biology at the University of Washington, agreed that the induced stem cells could prove to be a significant scientific advance.

Induced stem cells are "one of the biggest advances in biomedical science in the last decade," Murry said. "This is Nobel Prize-worthy stuff. They will lead to advances that are currently unimagined."

Roberts said that another advantage of the induced stem cells is they have a good chance of reducing the incidence of cancer caused by stem cell implants and reducing the amount of rejections.

But Goldstein said there are still risks involved in induced stem cells and that it remains unclear how effective these new stem cells can be.

"The problem is that these reprogrammed cells do have risks of cancer that are different than the kinds of risks for cancer with embryonic stem cells," Goldstein said. "And we are still trying to understand what the relevant issues are."

Goldstein said that though induced stem cells have many desirable properties, it is not yet known how similar they are to stem cells derived from embryos and whether they will turn out to be identical in their ability to be used in therapeutic approaches.

To create induced stem cells, Roberts' research team introduced four specific human genes into pig cells, causing the pig's own cells to become "reprogrammed" into an embryonic state. The work has primarily been done by lead investigator Toshihiko Ezashi, an assistant research professor at MU, and Bhanu Telugu, a postdoctoral fellow in the laboratory, Roberts said.

Roberts said huge progress is being made in this area but that the scientific community is still discussing what the new procedure will mean for the future of stem cell research.

Goldstein and Murry said that because of this uncertainty, research using both induced stem cells and embryonic stem cells must continue.

"It is premature to conclude that you can replace one stem cell type with any other," Goldstein said. "We don't know if they will be identical; it is too early to know.

"Anybody that tells you they know what is going to happen in five years probably has a crystal ball that I don't have."

Roberts said the next phase of his research will be to see if he can put the cells into pigs without causing any medical problems in the animals. He plans to test the procedure next on liver and blood cells.

However, the clinical phase of the project is not yet funded. Roberts estimates funding will need to be at least $300,000 annually, and the researchers are applying for grants. The current work is supported by grants from the National Institutes of Health and from the state of Missouri, including funds from MU's Food for the 21st Century Program.


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Comments

Symposier Share more. Grow more July 10, 2009 | 5:49 p.m.

What an amazing research Dr. Roberts! Hopefully in your second phase pigs will react successfully with the replaced cells. Since you are an specialist in Biochemistry, why don't you visit the next link in order to ger information about the "21st IUBMB International Congress" that you may find interesting to attend: http://www.symposier.com/events/vieweven...

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