Lab-grown “mini placentas” could be crucial to better understanding major disorders in pregnancy such as pre-eclampsia, scientists have suggested.
Academics said the development of pre-eclampsia can depend on issues with how the placenta develops in the first weeks of pregnancy and “is a process that is incredibly difficult to study”.
Using the mini placentas – developed by researchers at the University of Cambridge, the Wellcome Sanger Institute and the Friedrich Miescher Institute in Switzerland – could be key to understanding, predicting and preventing the condition.
The cellular models, also known as trophoblast organoids, gave the team a window into early pregnancy and how pregnancy disorders may develop.
Professor Ashley Moffett, of the department of pathology at the University of Cambridge, added: “This is a process that is incredibly difficult to study – the period after implantation, when the placenta embeds itself into the endometrium, is often described as a ‘black box of human development’.
“Over the past few years, many scientists – including several at Cambridge – have developed embryo-like models to help us understand early pre-implantation development. But further development is impeded because we understand so little about the interactions between the placenta and the uterus.”
In her previous work, Prof Moffett and her team pinpointed genes that can increase the risk of conditions such as pre-eclampsia or protect against them.
The research highlighted the role of cells found in the uterus, known as uterine natural killer cells, which cluster at the site the placenta implants on the endometrium.
Pre-eclampsia is a condition that affects some pregnant women and carries a risk of serious complications. The cause is not known, but it is thought to happen when problems with the placenta occur.
Early signs include high blood pressure and protein in the urine, with other symptoms including headaches, vision problems, vomiting and pain below the ribs.
For the latest study, published in Cell Stem Cell, the team used proteins secreted by these cells to the mini placenta to study the condition.
They identified proteins that aided the process and allowed the placenta to attach to the uterus, as well as several genes which help regulate blood flow.
Prof Moffett said: “This is the only time that we know of where a normal cell invades and transforms an artery, and these cells are coming from another individual, the baby.
“If the cells aren’t able to invade properly, the arteries in the womb don’t open up and so the placenta – and therefore the baby – are starved of nutrients and oxygen. That’s why you get problems later on in pregnancy, when there just isn’t enough blood to feed the baby and it either dies or is very tiny.”
Dr Margherita Turco of the Friedrich Miescher Institute, added: “Despite affecting millions of women a year worldwide, we still understand very little about pre-eclampsia.
“Women usually present with pre-eclampsia at the end of pregnancy, but really to understand it – to predict it and prevent it – we have to look at what’s happening in the first few weeks.
“Using ‘mini-placentas’, we can do just that, providing clues as to how and why pre-eclampsia occurs. This has helped us unpick some of the key processes that we should now focus on far more.
“It shows the power of basic science in helping us understand our fundamental biology, something that we hope will one day make a major difference to the health of mothers and their babies.”
The study was supported by Wellcome, the Royal Society, the European Research Council and the Medical Research Council.
