Scientists use amniotic fluid cells to grow mini lungs and other organs

Scientists have created mini-organs from cells that float in the fluid surrounding the fetus in the womb. This breakthrough, they believe, could open up new areas of prenatal medicine.

Mini-organs, or “organoids,” are tiny, simplified structures that can be used to test new medical treatments or to study the functioning of the real organs they mimic, both healthy and diseased.

Researchers from University College London and Great Ormond Street Hospital in the UK collected cells from amniotic fluid samples taken during 12 pregnancies as part of routine prenatal testing. Then they first grew mini-organs from cells taken during active pregnancy. Over time, their method could help doctors track and treat congenital diseases before birth, as well as develop personalized treatments for the baby in the womb.

“We’re very excited” about the possibility, said Mattia Gurley of University College London and author of the study published Monday in the journal Nature Medicine.

The tissue-specific stem cells collected by Gurley and his colleagues were released by the fetus, as typically occurs during pregnancy. Scientists determined which tissues the stem cells came from and found cells from the lungs, kidneys and intestines.

Until now, mini-organs were obtained from adult stem cells, which more closely resemble adult tissue, or from fetal tissue after an abortion.

Extracting cells from amniotic fluid circumvents regulations prohibiting the extraction of stem cells directly from fetal tissue, allowing scientists to obtain cells from a fetus in late stages of pregnancy. In the UK, the legal limit for terminating a pregnancy is usually 22 weeks after conception. Scientists cannot obtain fetal samples after this date, limiting their ability to study normal human development or congenital diseases after this date.

In the United States, abortion restrictions vary by state. In most cases, using fetal tissue for research is legal, explained Alta Charo, professor emeritus of law and bioethics at the University of Wisconsin at Madison. The US National Institutes of Health defines fetal tissue as tissue from a dead human embryo or fetus following miscarriage, abortion or stillbirth, and the use of tissue obtained from abortion has been controversial for many years.

Charo, who was not involved in the study, says the new method does not raise the same ethical issues. “Obtaining cells from amniotic fluid that has already been collected for routine clinical purposes does not appear to add any physical risk to either the fetus or the pregnant woman,” he said in an email.

Dr. Arnold Kriegstein, who directs the Stem Cell Development and Biology Program at the University of California, San Francisco and who was also not involved in the study, said that obtaining cells this way “may provide some information.” individual fruit while it grows.”

And because it takes four to six weeks to grow mini-organs from cells contained in amniotic fluid, prenatal therapy has plenty of time to correct any problems doctors may find, Gurley says.

To study the practical application of their method, the British team worked with colleagues in Belgium to study the development of babies with a condition called congenital diaphragmatic hernia, in which organs such as the liver and intestines move into the chest due to a hole. diaphragm. The lungs do not develop properly, and about 30% of fetuses with this disease die. If doctors find a hernia, they can operate on the fetus while it is still in the womb.

The researchers grew lung organoids from cells from fetuses with the disease before and after treatment and compared them with organoids from healthy fetuses. Dr Paolo de Coppi, one of the study’s authors from University College London and Great Ormond Street Hospital, said the method enabled them to assess the condition of a sick baby before it was born. At the moment, doctors cannot tell families much about the results of prenatal diagnosis, since each case is individual, he explained. The ability to study the functioning of prenatal mini-organs, De Coppi added, is the first step towards a more detailed prognosis and more effective treatment.

Kriegstein said more research is needed. “We are at a very early stage,” he added, “and we will have to wait to see its long-term usefulness.”

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