'Mini human placenta' may help prevent reproductive disorders

Scientists have successfully created 'mini-placentas' that can provide a window into early pregnancy and help transform our understanding of reproductive disorders such as still-birth and miscarriage.

Many pregnancies fail because the embryo does not implant correctly into the lining of the womb (uterus) and fails to form a placental attachment to the mother.

Yet, because of the complexities of studying this early period of our development, very little is understood about what is happening normally and what can go wrong.

Animals are too dissimilar to humans to provide a good model of placental development and implantation.

"The placenta is absolutely essential for supporting the baby as it grows inside the mother," said Margherita Turco, from the University of Cambridge in the UK.

"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. But our knowledgec of this important organ is very limited because of a lack of good experimental models," said Turco.

Organoids -- often referred to as 'mini-organs' -- enable insights into human biology and disease.

At the University of Cambridge, scientists are using organoid cultures to grow everything from 'mini-brains' to 'mini-livers' to 'mini-lungs'.

The team was able to grow organoids using cells from villi -- tiny frond-like structures -- taken from placental tissue.

These trophoblast organoids are able to survive long-term, are genetically stable and organise into villous-like structures that secrete essential proteins and hormones that would affect the mother's metabolism during the pregnancy.

Further analysis showed that the organoids closely resemble normal first-trimester placentas. In fact, the organoids so closely model the early placenta that they are able to record a positive response on an over-the-counter pregnancy test.

"These 'mini-placentas' build on decades of research and we believe they will transform work in this field," said Graham Burton, from Cambridge.

"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," Burton said.

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

In addition, the organoids may shed light on other mysteries surrounding the relationships between the placenta, the uterus and the foetus.

The organoids may also be used for screening the safety of drugs to be used in early pregnancy, to understand how chromosomal abnormalities may perturb normal development, and possibly even provide stem cell therapies for failing pregnancies.