AN INFERTILE woman is six weeks pregnant after a slice of one of her twin sister鈥檚 ovaries was grafted onto her own using keyhole surgery. This is the first time an ovarian transplant has resulted in a pregnancy.
Of course, most infertile women do not have twin sisters to help them. But the researchers say women could act as their own donors. If young women freeze part of an ovary, the implantation technique could be used to restore the tissue later in life, greatly extending their reproductive lifespan. A woman in Belgium recently gave birth after her own ovarian tissue, frozen before cancer treatment, was implanted back into her (麻豆传媒, 3 July, p 4).
鈥淚t鈥檚 much simpler than IVF,鈥� Sherman Silber, director of the Infertility and IVF Center of St Louis, Missouri, who performed the surgery, told a meeting of the American Society for Reproductive Medicine in Philadelphia this week. After the transplant, the recipient and her husband drove back to their home in Alabama the same morning.
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Although the 25-year-old sisters are identical twins, Melanie Morgan has three children while Stephanie Yarber had not menstruated since she was 14. Silber suspects that when Yarber was just an embryo, a genetic mutation occurred in the cell destined to form her ovaries. After attempts at IVF using Morgan鈥檚 eggs failed, and Yarber had run out of money, Silber鈥檚 team suggested the ground-breaking alternative to the women.
In April, the team removed one of Morgan鈥檚 ovaries in a 20-minute operation. They then grafted a part of the outer layer, where the egg follicles form, onto one of Yarber鈥檚 ovaries. The advantage of grafting a thin layer of tissue, rather than a full transplant, is that it does not require reconnection of the blood supply. Yarber started menstruating in August and fell pregnant shortly afterwards.
Because the twins are genetically identical, the ovarian graft will not be rejected by Yarber鈥檚 immune system. However, with anti-rejection drugs and regimes constantly improving, Silber predicts it will not be long before ovarian tissue from unrelated donors could be transplanted.