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Old 01-12-2008, 03:37 PM #1
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Default Embryos survive stem cell harvest

Embryos survive stem cell harvest
Company urges White House to endorse technique
A photomicrograph shows a single cell being removed from an eight-cell-stage human embryo. The biopsied cell undergoes a procedure to make it act like an embryonic stem cell, while the rest of the embryo is allowed to continue development.



MSNBC staff and news service reports
updated 3:17 p.m. ET, Thurs., Jan. 10, 2008
WASHINGTON - A company that devised a way to make embryonic stem cells without destroying human embryos Thursday urged President Bush to endorse the technique.

Massachusetts-based Advanced Cell Technology reported on Thursday that it has grown five batches of cells using the method, which is adapted from a procedure to test embryos for severe genetic diseases. Called preimplantation genetic diagnosis, or PGD, the procedure involves taking a single cell from an embryo when it contains only eight or so cells.

The technique usually does not harm the embryo, which is frozen for possible future implantation into the mother's womb. The team, led by ACT scientific director Robert Lanza, similarly froze human embryos and used the single cell that was removed as a source of human embryonic stem cells.

Lanza said the technique could be used to create mass quantities of embryonic stem cells without destroying a human embryo — in contrast with the methods currently used for extracting embryonic stem cells.

"This is a working technology, so it's here and now," Lanza told msnbc.com, "and it can be used to increase the number of stem cell lines available to federal researchers immediately. We could actually send these cells out to laboratories tomorrow."

Lanza hoped the cells would pass muster with the Bush administration, which is opposed to stem cell techniques that involve harming human embryos. Currently, only a limited number of human embryonic stem cell lines have been approved for federally funded research.

"If the White House approves this new methodology, researchers could effectively double or triple the number of stem cell lines available within a few months. Too many needless deaths continue to occur while this research is being held up," Lanza told Reuters. "I hope the president will act now and approve these stem cell lines quickly."

Years in the making
Lanza and his colleagues have been working on the embryo-safe technique for years. In 2006, they announced that they used the method to develop several new stem cell lines. A cloud was cast over those findings, however, when the researchers acknowledged that the study was merely a "proof of principle" and that all of the embryos in the experiment had to be destroyed.

This time, single cells were successfully extracted from the embryos, which had been donated for research by couples undergoing fertility treatment. About 80 percent of the embryos went on to develop into a state where they


In the earlier experiment, only 2 percent of the cells took on the characteristics of stem cells, and most of them turned into the kinds of cells that give rise to the placenta, Lanza said. This time, the efficiency rate was 20 to 50 percent, "which is exactly comparable to what has been reported for using entire embryos," he said.

Lanza credited the use of a protein called laminin, which apparently redirected the extracted cells into acting like a stem cell rather than eventual placental cells. He said the redirected cells thrived in lab dishes, as do true embryonic stem cells, and began to change into the various cell types.

"The stem cells we generated were completely normal and differentiated into all the cell types of the body, including insulin-producing cells, blood cells and even beating heart cells," Lanza said.

The findings were reported in a paper published online Thursday by the journal Cell Stem Cell.

The body's master cells
Embryonic stem cells are the body's master cells. They can give rise to every other cell type and are found in the earliest-stage embryos. Theoretically, the cells could be used to generate tissues to heal ailing spinal cords as well as hearts and other organs. However, moral and ethical concerns — and the resulting issue over federal funding — have held back progress.

Some researchers rely on less versatile alternatives to embryonic stem cells, such as adult stem cells or cells extracted from umbilical-cord blood and menstrual blood. Others have been looking for ways to make ordinary cells act like embryonic stem cells. Three teams of researchers reported progress last year in making what they call induced pluripotent stem cells — transformed skin cells that look and possibly act like embryonic stem cells.

Yet another team generated similar cells using human egg cells only, a process called parthenogenesis. But nearly all the researcher involved in such efforts say true embryonic stem cells must be studied as well.

Further research will be required to determine whether the induced pluripotent stem cells — or the cells developed by Lanza's team, for that matter — are truly as functional and safe as embryonic stem cells.

Lanza's colleagues in the Cell Stem Cell research include Young Chung, Irina Klimanskaya, Sandy Becker, Tong Li, Marc Maserati and Shi-Jiang Lu of Advanced Cell Technology; Tamara Zdravkovic, Olga Genbacev and Susan Fisher of the University of California at San Francisco; and Dusko Ilic and Ana Krtolica of California-based StemLifeLine.

This report includes information from Alan Boyle at msnbc.com and Maggie Fox at Reuters.

© 2008 MSNBC Interactive
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