Friday, April 5, 2013

Numbers matter in frozen embryo donation

Geoff Lomax is CIRM's Senior Officer to the Standards Working Group
Human embryonic stem cells generated from embryos donated after vitro fertilization
At CIRM, we often get questions from people wanting to know about donation of frozen embryos for use in research. The modified correspondence below is an example of the type of email I receive:
My name is Jane Doe. I have frozen embryos left over from my fertility treatment and I am interested in donating them for stem cell research. I am a 39-year-old mother of two young children and I do not intend to have more. Since last fall I've been corresponding off and on with researchers, but I have been unsuccessful in identifying a donation center. I am hoping CIRM can direct me to a donation center performing stem cell research.
In a Nature paper published today, CIRM President Alan Trounson and I investigate the growing interest in donating embryos for research. In that article, we cite a recent survey of 1,020 individuals or couples with frozen embryos that found donation for research was the most popular option once fertility treatments were complete. In California, of those who choose to donate to research about one-third of donors choose human development research, another third choose stem cell research and the remaining third choose both types. Embryo donors cite “wanting to help find cures for diseases like Alzheimer’s or diabetes” as reason for choosing stem cell research.

Another common source of embryos for use in stem cell research comes from those found to carry genetic diseases like muscular dystrophy, Huntington's disease and cystic fibrosis. These embryos are not used for reproduction and are typically destroyed. These embryos are, however, important for studying the specific disease they carry and rather than being destroyed can be donated for research. In fact, the majority of stem cell lines registered with the NIH in the past year are disease-specific.

A major point we make in our recent publication is that demand for frozen embryos for use in stem cell research, while still critical for the field, may be limited. CIRM grantees and others have been remarkably successful in making high quality embryonic stem cell lines available over the past five years. There are more than 1,000 lines identified in the International Stem Cell Registry. Some of these lines are created from healthy embryos and recently a number have been qualified as being safe for use in humans – “clinical grade lines.” Qualifying a cell line for human transplantation is expensive and time consuming.

Given these trends, where researchers are putting resources into “clinical grade lines” and disease specific lines, we suggest it is important to inform potential donors, like Jane Doe, that although the field does continue to need new frozen embryos, it does not need nearly the number that are available. In 2003, researchers estimated that 400,000 embryos were frozen in U.S. IVF clinics, but in our paper we give evidence for assuming that more than a million frozen embryos are now being stored by people who have completed their fertility treatments.

Given the large number of embryos currently stored in the U.S. and the smaller number needed by the field, we argue that research centers should consider how long they are willing to store donated embryos. If they are not prepared to store them indefinitely, donors like Jane should be told that their donated embryos could be discarded without being used in scientific studies. Donors may be disappointed by this fact, but details matter and it is important they have a clear picture of stem cell research.

G.L.

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