Belgian scientists have successfully performed an ovarian tissue transplant between nonidentical sisters for the first time.
Teresa Alvaro’s ovaries had failed due to damage caused by medical treatment. Following the transplant she started to menstruate again, and after a year doctors were able to recover two eggs from her ovaries.
The journal Human Reproduction reports that these were fertilised to produce two embryos. Ovarian tissue transplants have been carried out before – but only between twin sisters with the same genetic make up. In 1990, at the age of 20, Ms Alvaro received extensive treatment for beta-thalassemia, an inherited blood disorder, including chemotherapy and radiotherapy, and a bone marrow transplant from her young sister Sandra. The treatment was successful, but caused complete ovarian failure.
Ms Alvaro rejected the idea of an egg donation from her sister, as she wanted to be responsible for maturing the egg in her own body, and did not want her sister to have to take ovary-stimulating drugs.
The fact that Teresa had already received tissue from her sister was in her favour. Her sister’s cells had mixed with her own, and although they were genetically different, they were able to co-exist successfully together – meaning Teresa would not have to take drugs to stop her sister’s ovarian tissue being rejected.
A year after the transplant, the doctors retrieved two mature eggs from her ovary and fertilised them with her husband’s sperm. One of the resulting embryos developed to the two-cell stage and the other to the three-cell stage, but then both ceased to develop further, and so the embryos were not transferred to her uterus.