Manu
09-05-2001, 01:49 AM
The work by a team of researchers at the University of Wisconsin created cells known as hematopoietic precursor cells, which are primitive human blood cells. These cells develop into colonies of red blood cells, white blood cells and platelets, identical to those produced from human adult bone marrow.
The hope is such cells could be used to generate safe supplies of human blood and bone marrow cells for transfusion.
They could also help prevent immune rejection in patients receiving organ transplants.
As envisioned by the University of Wisconsin team, scientists would first infuse a patient with blood made from a particular line of embryonic stem cells. Then new organ tissue, created from the same stem cell line, would be created and implanted into the patient. The matching blood and tissue would hopefully prevent the body from rejecting the new tissue.
A Big Step
Embryonic stem cells are flexible cells that can develop into any of the some 220 types of cells and tissue that make up the human body. Researchers hope the cells, often derived from human embryos, can be used to create healthy replacement tissue for damaged tissue in patients suffering from a range of diseases.
The new research represents a big step in stem cell research since a major stumbling block for scientists has been in learning how to guide embryonic stem cells to develop into particular blood or tissues. However, the researchers caution, the work is still at very early stages and not near ready for human clinical trials.
"This is not something that's going to be available tomorrow or next year," says Dan Kaufman, a hematology fellow at the University of Wisconsin Medical School, and lead author of a paper about the research in the Proceedings of the National Academy of Sciences.
Kaufman and his colleagues don't yet know exactly what signals triggered the stem cells to grow into the blood-making cells. Rather than specifically directing the cells, the team grew them in the presence of mouse bone marrow cells. Since mouse and human cells are so similar, Kaufman believes the mouse cells released chemical signals that directed the formation of blood-forming cells. These signals were then recognized and followed by the human stem cells.
Contentious Research
Embryonic stem cell research has triggered a national debate between those who say the cells hold great medical promise and those who argue it is immoral to destroy early stage human embryos in order to take the cells for research.
Last month, President Bush offered a compromise decision on the matter, which allows federally funded researchers to use stem cell lines already in existence as of Aug. 9. He has restricted access by federally funded researchers to new stem cell lines created since his announcement.
All the available embryonic stem cell lines were derived from embryos that were created in in vitro fertility clinics but will not be used for reproduction.
Also participating in the study was James Thomson who, in late 1998, led the first successful effort to isolate and culture human embryonic stem cells. Thomson, also of the University of Wisconsin, helped develop five stem cell lines that now number among 64 that are now available to researchers using federal funding.
Although the news that researchers triggered human stem cells to form blood-making cells is a significant step in the field of stem cell research, others caution the work remains too expensive to use for any immediate practical application such as transfusions.
"With respect to using such a system for the production of red cells or white cells for transfusion, the cost of producing such cells would be absolutely prohibitive," Ernest Beutler, chairman of the Department of Molecular and Experimental Medicine at The Scripps Research Institute, told The Associated Press. www.abcnews.com (http://www.abcnews.com)
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Manu Narayan
The hope is such cells could be used to generate safe supplies of human blood and bone marrow cells for transfusion.
They could also help prevent immune rejection in patients receiving organ transplants.
As envisioned by the University of Wisconsin team, scientists would first infuse a patient with blood made from a particular line of embryonic stem cells. Then new organ tissue, created from the same stem cell line, would be created and implanted into the patient. The matching blood and tissue would hopefully prevent the body from rejecting the new tissue.
A Big Step
Embryonic stem cells are flexible cells that can develop into any of the some 220 types of cells and tissue that make up the human body. Researchers hope the cells, often derived from human embryos, can be used to create healthy replacement tissue for damaged tissue in patients suffering from a range of diseases.
The new research represents a big step in stem cell research since a major stumbling block for scientists has been in learning how to guide embryonic stem cells to develop into particular blood or tissues. However, the researchers caution, the work is still at very early stages and not near ready for human clinical trials.
"This is not something that's going to be available tomorrow or next year," says Dan Kaufman, a hematology fellow at the University of Wisconsin Medical School, and lead author of a paper about the research in the Proceedings of the National Academy of Sciences.
Kaufman and his colleagues don't yet know exactly what signals triggered the stem cells to grow into the blood-making cells. Rather than specifically directing the cells, the team grew them in the presence of mouse bone marrow cells. Since mouse and human cells are so similar, Kaufman believes the mouse cells released chemical signals that directed the formation of blood-forming cells. These signals were then recognized and followed by the human stem cells.
Contentious Research
Embryonic stem cell research has triggered a national debate between those who say the cells hold great medical promise and those who argue it is immoral to destroy early stage human embryos in order to take the cells for research.
Last month, President Bush offered a compromise decision on the matter, which allows federally funded researchers to use stem cell lines already in existence as of Aug. 9. He has restricted access by federally funded researchers to new stem cell lines created since his announcement.
All the available embryonic stem cell lines were derived from embryos that were created in in vitro fertility clinics but will not be used for reproduction.
Also participating in the study was James Thomson who, in late 1998, led the first successful effort to isolate and culture human embryonic stem cells. Thomson, also of the University of Wisconsin, helped develop five stem cell lines that now number among 64 that are now available to researchers using federal funding.
Although the news that researchers triggered human stem cells to form blood-making cells is a significant step in the field of stem cell research, others caution the work remains too expensive to use for any immediate practical application such as transfusions.
"With respect to using such a system for the production of red cells or white cells for transfusion, the cost of producing such cells would be absolutely prohibitive," Ernest Beutler, chairman of the Department of Molecular and Experimental Medicine at The Scripps Research Institute, told The Associated Press. www.abcnews.com (http://www.abcnews.com)
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Manu Narayan