Wonder cure?: A colony of human embryonic stem cells.
Credit: Wikipedia
There had been hope that the animal eggs could be used as a substitute for human embryos, which are difficult to harvest and controversial to use.
"This very important paper suggests that livestock oocytes (the cells from which eggs develop) are extremely unlikely to be suitable as recipients for use in human nuclear transfer," said Ian Wilmut, director of the Centre for Regenerative Medicine in Edinburgh, Scotland, and leader of the team who cloned Dolly the sheep.
"This is very disappointing because it would mean that production of patient-specific stem cells by this means would be impracticable," said Wilmut.
"Disappointing result"
Working with human embryos is also impractical because the high failure rate means it takes hundreds of eggs to create a single stem cell line, said Alan Trounson, president of the California Institute for Regenerative Medicine.
"Most people are working on IPS cells (stem cells derived from skin) rather than nuclear transfer because it's so difficult to get human eggs," Trounson said.
The new study "is endorsing that we could use human eggs, but I don't think it helps us, to be honest, in actually being able to do it, because it doesn't show that it could be improved dramatically."
Trounson said human cloning can still be important in addressing some serious genetic diseases because it would allow for the manipulation of mitochondria, which are found in the body of a cell and not the nucleus, contain DNA and have a role in cell function.
But Lanza said it's too soon to give up on embryonic stem cell research. "We need to continue research on both fronts because we don't know if IPS cells or cloning will be better," he said. "It's good to have a backup approach."
