Using building material from cloned cow embryos, scientists say they have constructed miniature kidneys that appear to function similar to genuine organs. Embryos contain master cells called stem cells that have the potential to grow into any tissue in the body. In this case, they grew the embryos to the stage where they could identify cells destined to become kidney cells. While it is still unclear whether these made from cloned embryos can perform all the duties of the ordinary variety, the researchers said they work well enough to produce urine.
"It's one of the more provocative pieces of news that I've heard from this whole area. We can't evaluate the claim without seeing the data. There are many, many years of work ahead of us. These are exciting but very preliminary data," said Dr. George Q. Daley, a stem cell expert at the Whitehead Institute in Cambridge, Massachusetts.
The ultimate goal of the research is to find replacement parts for worn out or damaged human organs, starting with cells from test-tube embryos that are genetic twins of the recipient. Researches hope eventually to construct new organs that are genetically identical to the recipient's own body. This would eliminate the need for ordinary transplants and avoid the use of drugs to prevent rejection of the new organ.