A new artificial womb model has replaced premature lambs with a real mother for almost a month.
A premature baby is not ready for independent life, and a premature meeting with the outside world often ends sadly for him. This is especially true for children born not just early, but too early – before the 26th week of pregnancy. There are methods that can save the life of a child born between the 22nd and 23rd weeks, but the mortality rate of such children still remains high – up to 90%. And even if the child survives, he is at risk of diseases associated with prematurity in the future.
A human embryo at 9–10 weeks of development. (Photo: lunar caustic / Flickr.com) A lamb in an artificial uterus filled with artificial amniotic fluid. For gas exchange, blood is pumped through a “placenta” device, which removes carbon dioxide from the blood and saturates it with oxygen. (Image: Children’s Hospital of Philadelphia ‹ › View full size
In such cases, a device with which one could “carry to term” the fetus, which would be a substitute for the mother’s uterus, would be very useful. Such devices are being actively developed, but so far the models of artificial wombs have not been entirely perfect: for example, one of them supported the life of a premature goat for 22 days, but the animal had to be kept on a ventilator, constantly undergoing blood dialysis, and, in addition, The kid’s muscles remained so weak that he could not move at all.
The new model, which is described in Nature Communications by researchers from the Center for Embryonic Development at the Children’s Hospital of Philadelphia, supports a premature fetus for 28 days – experiments were carried out on lambs that were born on the 110-115th day, while a normal pregnancy in sheep lasts 152 day; if we were talking about a person, this would be exactly the 22–24th week. Both during and after ripening, the lambs remained quite normal and healthy – obviously, thanks to some features of the new device.
It is known that the lungs of a very premature fetus are not yet able to work with air, and precisely because premature babies had to breathe on their own, they later developed problems with the lungs, which developed with abnormalities. In the new artificial uterus, the fetus lies in a plastic bag, but around it is not air, but a special liquid that imitates the amniotic fluid in the mother’s womb. Gas exchange in the blood was ensured by an external attachment that worked like a placenta: the blood of lambs entered this “placenta” through an artificial umbilical cord, which removed carbon dioxide from the blood and saturated it with oxygen.
In addition, the heart of the lambs worked on its own – according to the authors of the work, if any, even a very weak, external pump is connected to the bloodstream, the underdeveloped heart will be overloaded. The fetus in the artificial uterus was completely protected from changes in temperature, pressure, light and, of course, from infections; special electronics constantly monitored his physiological parameters.
After 28 days, it turned out that the lungs of lambs matured in this way were completely healthy and functioned in the same way as those of ordinary lambs born on time; other organs – brain, liver, etc. – were also fine. One of them is four months old, the other is already more than a year old.
In the near future, researchers want to repeat the experiment with animals and then move on to children; but before moving on to clinical trials, it will be necessary to adjust the size of the artificial uterus to human standards (since early-born children have smaller lambs) and find out what substances and in what proportions need to be added to the artificial amniotic fluid – it is obvious that in different species of animals its composition should be at least slightly different.