Stem cell research in the United States has been hobbled for years by severe and misguided restrictions on federal funding. But now a vexing additional problem is slowing even privately financed research. There are distressingly few women willing to donate their eggs for experiments at the frontiers of this promising science.
A respected team of stem cell researchers at Harvard spent nearly $100,000 over the course of a year advertising for egg donors. Hundreds of qualified women were interested enough to call but, after hearing what was entailed, not one was willing to donate eggs. Many were likely deterred by the time, effort and pain required — including daily hormone injections and minor surgery — to retrieve the eggs. And they were almost certainly discouraged by the meager compensation.
Although women can be paid thousands of dollars to donate eggs for fertility treatments, ethical guidelines and some state laws say they cannot be paid much for donating to research. These restrictions are meant to protect the women against exploitation, but they have created a dearth of egg donors for stem cell research.
Surplus embryos from fertility clinics can seldom be used to study specific diseases or develop treatments for them. Scientists need to develop new stem cell lines genetically matched to patients with diseases like diabetes or Parkinson’s. They typically take the nucleus of a patient’s skin cell and inject it into an egg whose nucleus has been removed. If all goes well, the desired stem cell can be derived from the result.
With few human eggs available, some privately financed stem cell scientists are studying animal eggs to see if they can work the same magic when injected with a human nucleus. That may send shivers of apprehension through people who imagine rogue scientists creating grotesque half-human, half-animal creatures in the laboratory. But a thorough examination of the process by British regulators should alleviate such fears.
The British have approved, in principle, the creation of “cybrid embryos,” produced when scientists grow human embryos in animal eggs. Although the embryos would be, in some sense, animal-human hybrids, there would be remarkably little animal — only about 0.1 percent — in the mix. The embryos, and the stem cells derived, would be virtually identical to cells in the patient.Continue reading the main story
There is little doubt that human eggs would be better for research and ultimately treatment. But with a shortage of donors, animal eggs could prove a valuable alternative. Meanwhile, many scientists are hoping that it will be possible, without using eggs at all, to convert human skin cells directly into embryonic stem cells, as has been shown possible in mice. That would be an elegant solution to the vexing egg donor problem.Continue reading the main story