for National Geographic News
Recent weeks have seen major breakthroughs in stem cell research, including the restoration of vision in blind mice and the use of human stem cells to produce insulin "naturally" in diabetic mice.
Human stem cell treatments for these and other diseases may in some cases be at least a decade away. But each new discovery has added to the notion that stem cell research is showing increasing signs of living up to the hype surrounding it.
"I think it was an act of faith a couple of years ago that [something like the vision-restoration process] should work, but now we have some clear examples that it really is working," said Thomas Reh, a professor in the University of Washington's Department of Biological Structure in Seattle.
Stem cells are primal cells that have the potential to transform into various cells and tissues found in the human body.
They could potentially be used to repair tissue, grow new organs, or lead to treatments for a wide range of ailments.
There are many types of stem cells, from adult stem cells derived from umbilical cord blood or bone marrow, to stem cells taken from human embryos.
Most scientists say embryonic stem cells have the greatest research potential, because they can develop into more cell types than other stem cells. But embryonic stem cell research is controversial, because starting a stem cell line in most cases requires the destruction of a human embryo. (Related: "Stem Cells Can Be Collected Without Destroying Embryos, Scientists Show" [August 23, 2006].)
Some of the recent studies, however, highlight the potential for treating illness with adult stem cells, which are not fraught with the same ethical concerns as embryonic stem cells.
In a study published in November in the journal Proceedings of the National Academy of Sciences, researchers reported that stem cells derived from human bone marrow and transplanted into diabetic mice stimulated the animals' pancreases to produce insulin, repairing damage caused by diabetes.
"This fits with a large body of evidence that these cells have this remarkable ability to go to injured tissues and repair them," said the study's lead author, Darwin Prockop, the director of the Center for Gene Therapy at the Tulane University Health Sciences Center in New Orleans, Louisiana.
In the future, Prockop said, "the therapeutic idea would be to take small amounts of marrow from patients, then grow a large number of these cells, and give them back to the same patient to heal tissue."
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