US stem cell researchers have called for prohibitions on the payment of compensation to egg donors to be removed if an egg shortage crisis is to be avoided. In an article published in Nature last week, Kevin Eggan and Douglas Melton from Harvard University's Stem Cell Institute claim the lack of available eggs is hindering the progress of stem cell research in the US. They explain how researchers are facing difficulties in obtaining human eggs for use in 'therapeutic cloning' because in the states that prohibit researchers to pay egg donors woman are choosing to donate their eggs to fertility clinics instead. Fertility clinics are permitted to pay donors, who can receive up to $10,000 per donation, but some states do not allow payments to be made in cases where eggs are donated for research purposes. In these situations, stem cell researchers must instead rely on 'spare' eggs left over after IVF or on donors to give eggs altruistically.
Eggs are necessary for SCNT - so called 'therapeutic cloning' - which some believe could lead treatments for a number of diseases. The technique involves extracting genetic material from a host patient and inserting it into a human egg which is then fertilised. The resulting embryo, from which stem cells can then be extracted, will be an identical genetic match to the host patient.
There is no federal legislation governing egg donation in the US and it is left up to each state to regulate in this area. The states of California and Massachusetts - both of which have passed measures that allocate state funds to therapeutic cloning (embryonic stem cell (ES cell) research is not federally funded in the US and some states have legislated to ban 'therapeutic cloning' on ethical grounds) - have put in place prohibitions on compensating egg donors. The article suggests these restrictions came about in part as a political compromise to appease opposition when introducing pro-cloning measures.
In the UK, egg and sperm donors are prohibited from receiving payments by the Human Fertilisation and Embryology Authority (HFEA). Donors may only claim for 'reasonable expenses' incurred during the process. These may include travel costs and loss of wages, but the remuneration is capped at £250 per donation. The HFEA permits 'altruistic' egg donation allowing women to donate eggs solely for scientific research and in July 2006, it approved an egg-sharing initiative offered by offered by the Newcastle NHS Fertility Centre and the North-East England Stem Cell Institute (Nesci). Under these arrangements, women who require fertility treatment are offered money towards the cost of IVF if they choose to donate some of their eggs to research. Similar egg sharing arrangements exist in the US, but there are concerns over the declining quality of eggs as donors become older. Researchers say eggs from females in their early twenties achieve the best cloning success rates but on average women who require fertility treatment tend to be older.
The issue of paying for eggs carries with it practical and ethical concerns. There is a small risk of ovarian hyperstimulation (OHSS) to the donor that some feel is too great to allow woman to assume on altruistic grounds, let along offering a financial incentive to donate. Opponents argue that compensation amounts to the exploitation of poorer donors. There are also concerns about the impact paying for eggs may have on the doctor-patient relationship, as fertility doctors' could face new conflicts of duties arising between the researcher, the patient and the donor.
If 'therapeutic cloning' is to reach its maximum potential, the article suggests, a secure source of eggs is necessary. In the absence of this, alternative methods of creating stem cells genetically matched to the patient may provide an answer. Last year, scientists announced they had managed to 'reprogramme' skins cells creating induced pluripotent stem cell (iPS cells). These cells would have embryonic-like properties and would also be a genetic match to the patient. Until alternative methods are proven to be viable, however, many researchers say that all avenues must be explored.
Sources and References
Egg shortage hits race to clone human stem cells