First step towards the creation of an artificial uterus for premature children

There are still challenges ahead such as the development of an amniotic fluid or the connection of the artificial uterus to the newborn by the umbilical cord

Can a machine replace the maternal placenta? To date, no device has been able to emulate Nature, but a group of researchers from the Children's Hospital of Philadelphia, in the United States, has just demolished a scientific barrier that seemed insurmountable. They have also achieved it with a simple ingenuity: a sophisticated plastic bag (biobag), filled with an artificial amniotic fluid, attached to an extracorporeal circulation system (such as those used in cardiac surgeries to temporarily supplant the functions of the lungs and the heart).

In this biobag or "smart bag" have achieved several very premature lamb fetuses complete their development for four more weeks to be born healthy and without sequelae of any kind. The success of this experiment, published in the journal Nature Communications, is the first step towards the development of an artificial human uterus, capable of housing and helping very premature babies to grow.

Researchers at the Hospital of Philadelphia have tested the device with lamb fetuses of 15 and 17 weeks gestation. Translated to the human biological age, they would be like neonates of 23 or 24 weeks, children between five and six months of gestation. The researchers extracted the fetuses with a cesarean and carefully placed them inside the bag where they were floating in a liquid rich in salts. Then they connected the extracorporeal circulation pump to the umbilical cord and monitored them for a month.

Healthy development

The "biobag" reproduced the environment of the uterus and functioned like the placenta of a mammal, providing the necessary oxygen and nutrients as if it were a mother. During this time, the immature organs of the lambs completed their development and were born healthy when leaving the bag. Most were sacrificed to be able to perform the autopsy and check the status of their organs. The autopsy showed a healthy development and no abnormalities were found in the brain and lungs, the organs that in the fetus take longer to complete their development, according to data from the Hospital of Philadelphia. One of the lambs that did not sacrifice was one year old and still healthy.

The system must be perfected to house human fetuses, "but it could prevent the serious consequences that extremely premature children suffer," says Alan Flake, lead author of this research. Flake works in an artificial placenta that can maintain in stable conditions premature babies born between 28 and 23 weeks of gestation. "Babies (in that period) have an urgent need for a bridge between the maternal womb and the outside world. If we can develop an extrauterine system that supports growth and maturation for a few weeks, we can improve the outlook in an extraordinary way, "says the researcher.

An important step

Large premature babies when they come into the world bulge little more than a state-of-the-art mobile phone. Your chances of getting ahead are counted in days of gestation and in grams of weight. Surviving with less than 24 weeks is always a small miracle and when they do they do it, almost always, with serious sequels. No matter how sophisticated the hospital care is.

"The limit of viability of a premature baby is 500 grams and 24 weeks of gestation. Those who manage to survive do so with neurodevelopmental problems, chronic lung disease and severe digestive disorders, among many other problems, "explains Carmen Bravo Laguna, deputy neonatology physician at La Paz Hospital in Madrid, a reference center for the care of premature babies. in Spain. Bravo applauds "the important step" that the Children's Hospital of Philadelphia has given, although he believes that jumping to humans will not be easy. The greatest difficulty that must be overcome is the connection of the artificial uterus to the newborn through the umbilical cord, rather than the development of an amniotic fluid suitable for human babies, says the neonatologist. "Connecting the umbilical vessels to a cannula has a high risk of bleeding and thrombosis. In a premature baby the risk of suffering a cerebral hemorrhage is high and the connection to the cannula can raise it even more », he explains. The American researchers, however, already date that moment. They think they could do it in three or five years.

After the success of the experiment in animal models, the next step is to improve the fluid in which premature infants will float. The amniotic fluid contains nutrients and growth factors, also fetal urine. The goal is to add substances that are known for their ability to aid in fetal development. You also want to change the aspect of the device. The objective is to improve the image. You do not want to see human fetuses hanging from plastic bags. It will be designed with a shape more similar to a conventional incubator, with a cover that keeps babies in darkness. The closest thing to the maternal womb.

And dreaming, Alan Flake imagines his new ingenuity as a "friendly" incubator also for parents, that is able to reduce the stress of parents and maintain the bond with their child. In Flake's project, the artificial placenta or uterus allows parents to communicate through sound and see it through a camera.