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Working human placentas grown outside of the womb to help prevent miscarriage and stillbirth

The model of human placentas will allow scientists to understand the very early stages of pregnancy which are the most vulnerable  - Getty Images
The model of human placentas will allow scientists to understand the very early stages of pregnancy which are the most vulnerable - Getty Images

Working human placentas have been grown outside of the womb to help scientists understand why more than 300,000 pregnancies fail in Britain every year, and how to stop diseases like zika.

The breakthrough gives researchers a living organ on which to test theories about what damages the placenta and what can be done to fix the problems.

Many women miscarry or have stillbirths because the placenta fails to attach to the mother properly after conception, starving the baby of oxygen and nutrients.

Yet because it is impossible to see what is happening inside the womb in the very early stages of pregnancy, very little is understood about the process or why it goes wrong.

“The placenta is absolutely essential for supporting the baby as it grows inside the mother,” says Dr Margherita Turco, the study’s first author, from the Departments of Pathology and Physiology, Development and Neuroscience at the University of Cambridge.

“When it doesn’t function properly, it can result in serious problems, from pre-eclampsia to miscarriage, with immediate and lifelong consequences for both mother and child.”

In Britain nearly 700 babies are miscarried each day and 164 born preterm. There are also around 3,500 stillbirths each year.

The mini-placenta shown under a microscope - Credit:   Margherita Turco, University of Cambridge
The mini-placenta shown under a microscope Credit: Margherita Turco, University of Cambridge

To create the mini-organs, scientists used villi - tiny finger-like protrusions - taken from placental tissue of aborted foetuses and grew them into three dimensional structures which secreted the same proteins and hormones needed in pregnancy.

Analysis showed the placenta acts like it would in the crucial first-trimester, attempting to burrow into tissue as it would in the womb, and even recording a positive response to an over-the-counter pregnancy test.

Professor Graham Burton, a co-author and Director of the Centre for Trophoblast Research at Cambridge, said: “These ‘mini-placentas’ build on decades of research and we believe they will transform work in this field.

“They will play an important role in helping us investigate events that happen during the earliest stages of pregnancy and yet have profound consequences for the life-long health of the mother and her offspring.

“The placenta supplies all the oxygen and nutrients essential for growth of the foetus, and if it fails to develop properly the pregnancy can sadly end with a low birthweight baby or even a stillbirth.”

The scientists knew they had created working placentas when they tested positive using a pregnancy tests showing they emitting the correct hormones  - Credit:  Margherita Turco, University of Cambridge
The scientists knew they had created working placentas when they tested positive using a pregnancy tests showing they emitting the correct hormones Credit: Margherita Turco, University of Cambridge

Researcher are also hoping the mini-organs will help them understand why some diseases, such as zika, can be passed from the mother to the growing baby, even though others are blocked.

And they may be useful for screening the safety of drugs used in early pregnancy, or even provide stem cell therapies for failing pregnancies.

Last year, the same team announced they had grown miniature working models of the lining of the womb.

“Now that we’ve developed organoid models of both sides of the interface – maternal tissue and placental tissue – we can start to look at how these two sides talk to each other,” added  Ashley Moffett, emeritus Professor of Eeproductive Immunology at Cambridge.

“We can also by gene editing look at the genes that determine healthy pregnancy and the products coming off might be very useful biomarkers. At the moment we cannot predict or prevent problems so we think this will be transformative.”

Commenting on the study Prof Magdalena Zernicka-Goetz, Professor of Mammalian Development and Stem Cell Biology, University of Cambridge, said she was hoping to combine the breakthrough with her own work on creating embryos from stem cells.

“By combining these two models - of the placenta and of the embryo - it should be possible to provide knowledge of how to rescue failing pregnancies.  

“This would be a huge dream come true.”

The research was published in the journal Nature.