Biodegradable scaffolds help infertile rabbits have normal pregnancy

Researchers say the approach could have implications for women affected by uterine infertility.

Rabbits have had normal pregnancies and live births after their injured uteri were repaired using a method of tissue engineering with their own cells. Researchers say this bioengineering approach could have implications for women affected by uterine infertility.

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Approximately 6 per cent of women undergoing infertility treatment have dysfunction of the uterus.

While transplants from live or deceased donors have enabled live births in humans, a lack of donor organs and the need for immunosuppressive drugs to support the transplanted uterus limit its use.

Bioengineering had been shown to repair small uterine defects in rodents, but live birth in these or larger animals had not yet been achieved.

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Anthony Atala, principal investigator and director of the Wake Forest Institute for Regenerative Medicine (WFIRM) in the US, said: “The study shows that engineered uterine tissue is able to support normal pregnancies, and foetal development was normal, with offspring size and weight being comparable to those from a normal uterus.

“With further development, this approach may provide a pathway to pregnancy for women with an abnormal uterus.”

Scientists implanted biodegradable scaffolds — some with the rabbits’ own uterine cells inserted and some without — into the damaged uteri of 78 rabbits. The uteri were examined at one, three and six months, in the study published in Nature Biotechnology.

The authors found the scaffolds had degraded three months after implantation, and by six months they observed no obvious differences between the engineered and native tissues.

Four of the 10 rabbits that received scaffolds seeded with uterine cells had normal pregnancies to term, but none of the 10 rabbits that received unseeded scaffolds did.

Co-author Koudy Williams, said: “Our results indicate that the tissue-engineered uteri responded to the expansion and mechanical strains that occur during pregnancy. Further pre-clinical studies are being planned before clinical trials are contemplated.”

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Gudrun Moore, professor of molecular genetics at UCL, said: “I think this is an excellent study using rabbits as a model, with detailed histochemical and biochemical analysis and all the appropriate controls.

“I believe this type of experiment offers real hope for the 6 per cent of women with uterine infertility and pushes forward the field in the hope that one day the use of biodegradable polymer scaffolds seeded with autologous cells taken from the uterus of infertile women may help achieve normal pregnancies and births, although we need a lot more research first.

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“More pre-clinical studies are needed to increase the number before clinical studies can be performed in humans.”

Reader Q&A: What is the evolutionary benefit of morning sickness during pregnancy?

Asked by: Cerian Bolton, Ely

Morning sickness in pregnancy appears to be unique to humans, and it seems that women with more severe morning sickness have a lower rate of miscarriage. There are two main theories to explain why we might have evolved this.

The first is that the nausea is commonly associated with an aversion to meat and strong tastes, and this might be a way of steering the mother away from foods that might cause food poisoning, especially early in pregnancy when the foetus is most vulnerable.

The second theory is that morning sickness is caused by the hormones secreted by healthy foetuses, which are important for building the placenta in the first trimester. In that case, the nausea is just an unfortunate side effect of these hormones, and the advantage is an indirect one.

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