GERON....GERN
Nov. 5
WASHINGTON, Nov 5 (AFP) - Two teams of US researchers have successfully cultivated for the first time in the laboratory human cells that could someday be used to grow from scratch anything from heart muscle to brain tissue.
The ability to cultivate indefinitely human embryonic stem cells -- the unspecialized "parent" cells to all tissues in the body -- opens up new possibilities for future treatment of people suffering from heart disease, neurodegenerative disorders like Parkinson's, diabetes and some forms of cancer, says Friday's edition of Science magazine.
The findings could also someday lead to treatments that would eliminate the problem of a limited supply of organ donors, this study says.
"(Our work) shows you can derive and culture these cells, and it opens the possibility for some dramatic new transplantation therapies," said James Thomson, a developmental biologist at the University of Wisconsin at Madison and author of the study.
Many diseases, such as Parkinson's and juvenile onset diabetes, occur because of the death or dysfunction of just one of a few cell types, whose replacement would offer lifelong treatment.
Similarly, heart muscle cells grown from stem cells could be injected directly in a person with heart disease to shore up failing tissue.
But until now only the stem cells of mice and higher animals had been grown, making the development of human stem cells a kind of biological holy grail.
After deriving the embryonic stem cells from the inner cell masses of donated human embryos several days after fertilization, Thomson's team observed the cells as they developed into cartilage, bone, muscle, neural and gut cells.
"Not only should scientists be able to generate specific nerve, muscle, skin or other cells for transplantation, but we should also be able to alter these cells ... to reduce the likelihood of rejection," said John Gearhart, professor of obstetrics, gynecology and physiology and leader of the second team from John Hopkins University in Baltimore, Maryland.
"We could make universal donors," he said, and also develop therapies for spinal cord injuries, muscular dystrophies, atherosclerosis and wound healing.
In the second study, which was reported in the November issue of Proceedings of the National Academy of Sciences, the Johns Hopkins team reached similar results using non-living, human fetal tissue to find cells which, under specific conditions, developed into true stem cells that then differentiated into more advanced tissues.
"Our hope is that these cells could be ... used to regenerate failing tissue," said Thomas Okarma, vice president for research and development at California-based biotechnology company Geron Corp., which supported the research carried out by both teams of scientists.
"Because these cells do not age, they could be used to generate virtually a limitless supply of cells and tissue for transplantation."
But the authors of the first study warn that such clinical applications are perhaps as much as a decade away. Scientists must first learn how to direct the stem cells so that they develop into the specialized, more advanced type of cell needed.
They must also overcome opposition on ethical grounds to using products from human embryos. Current laws prohibit using federal money for such research.
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