Monday, January 14, 2008
Stem cell research discovery revealed - colonies without destroying embryo
Stem cell the cell for colon is a mordern and latest invention that can change the generation next.
Scientists at an Alameda company claim they have created human embryonic stem-cell colonies without destroying an embryo -- a breakthrough they say has the potential to end the ethical debate surrounding the use of embryos to derive the cells.
The development was announced Thursday and is an improvement on a technique that the White House and other skeptics scoffed at when it was first revealed in 2006.
"This new approach addresses the president's ethical concerns," said William Caldwell, chief executive of Advanced Cell Technology, which has offices on Harbor Bay Parkway and in Worcester, Mass.
But Story Landis, who heads the federal government's National Institutes of Health stem-cell task force, was non-committal.
While calling the new procedure "extremely interesting," she added, "we need to know more" about the method to make sure that embryos are not harmed in the process.
Richard Doerflinger, a bioethicist at the U.S. Conference of Catholic Bishops, was highly critical.
"It seems they've made some progress in reducing the direct destructiveness of the procedure," he said. However, he added, "this is a rather shaky claim about making this procedure safe," because while most of the embryos used to create the stem-colonies survived, a few did not.
Moreover, he said, creating stem-cell colonies from skin -- as some scientists have shown to be possible recently -- is far preferable because "it totally does not have any problem in terms of harming
or destroying embryos."
The new study was published Thursday in the journal Cell Stem Cells.
While the study involves a technique developed by Advanced Cell Technology, it was replicated by researchers at StemLifeLine in San Carlos.
"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," said the Alameda's company's Dr. Robert Lanza, the paper's senior author. "Too many needless deaths continue to occur while this research is being held up."
When Advanced Cell Technology first published a study detailing the technique in 2006, it said it removed a single cell from a tiny, early-stage embryo and demonstrated that the cell could be turned into a stem-cell colony without destroying the embryo.
That was hailed at the time by some stem-cell advocates as a major breakthrough.
Because human embryonic stem cells can develop into any type of tissue, many scientists believe it may be possible one day to create colonies of them that can be used for everything from growing replacement organs to creating treatments for diabetes and other diseases.
However, soon after Advanced Cell Technology's first study was published, the company acknowledged it actually had not kept alive some of the embryos used to create the colonies. Its executives explained that their purpose was merely to demonstrate the technique would work, not to keep the embryos alive.
Nonetheless, the revelation in 2006 was denounced by Doerflinger. White House officials also said the procedure continued to raise ethical concerns about deriving stem-cell colonies from embryos.
In this latest study, the company's executives said they found a better way to grow the cells removed from the embryos and that 80 percent of the embryos developed normally, although all of them eventually were frozen.
Susan Fisher, a stem-cell researcher at the University of California-San Francisco, praised the technique.
"For people for whom embryonic destruction is an obstacle in this kind of work, this is certainly an advance," said Fisher, who also provided advice for the study.
Staff writer Peter Hegarty contributed to this report.
More about Stem cell
Stem cells are cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s. The two broad types of mammalian stem cells are: embryonic stem cells that are found in blastocysts, and adult stem cells that are found in adult tissues. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin or intestinal tissues.
As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed. In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates.