Bioengineered lungs
Artificial lungs successfully transplanted to pigs
Anna Kerman, XX2 century
Artificially grown organs may become available to seriously ill patients in the next five years.
Such an optimistic forecast appeared due to the fact that scientists were able to successfully transplant pig lungs obtained by bioengineering methods.
Pig lungs in a bioreactor
A team from The University of Texas Medical Branch (The University of Texas Medical Branch, UTMB) demonstrated that organs grown in the laboratory quickly take root in animal organisms: two weeks after transplantation, the transplanted lungs acquired their own network of blood vessels.
Previous experiments in this area ended in failure within a few hours after the operation — primarily due to problems with the blood supply of the transplanted organ. Now, researchers note that the lungs function normally two months after surgery. At the same time, the indicators of saturation (saturation of red blood cells with oxygen) are about 100% — this means that the new lungs fully provide the body with oxygen.
The new method can help overcome the global crisis of donor organs — there are much more organs in need of liver, heart or, in fact, lungs than there are organs available for transplantation. As a result, many patients die without waiting for a "suitable" heart, while others are forced to regularly resort to expensive treatment in order — as far as possible — to compensate for the condition.
"Sometime in the future, we will be able to take a patient's stem cells and create an organ that is, in fact, his own, with [full] compatibility at the tissue level. It will no longer be necessary to use immunosuppression in order for the new organ to function the same way as the original one," says Joan Nichols, professor of therapy at UTMB.
According to scientists from Texas, the first patients with artificial lungs grown using bioengineering may appear in 5-10 years.
As part of the experiment, the researchers took the pig's lungs and left them with only a "frame" free of blood and cells. Then the scientists created a mixture of nutrients and stem cells of the recipient pig and placed the previously obtained "skeleton" of the lungs in this liquid.
Bioengineered lungs on the eve of transplantation
The lungs grew on "frames" for 30 days, and then were transplanted to 4 pigs. The animals were killed 10 hours, 2 weeks, 1 month and 2 months after the operation — such a schedule was necessary to study the development of blood vessels in a new organ.
The state of health of all four experimental animals after the operation was normal. Already 2 weeks after the transplant, the new lungs had the necessary blood vessels for life.
Now the donor lungs are modified before surgery so that they fit the recipient in size. In addition, recipients are forced to take immune suppressing drugs to reduce the risk of rejection of the donor organ. But if the organ is seeded with the patient's own cells, rejection will not occur.
Although in the near future human lungs will be used to create a "frame", in the future they may be replaced by "skeletons" of lungs printed on a 3D printer.
In the meantime, scientists have managed to transfer the successful experience of experiments with small animals to large animals. The next step will be lung transplantation with further long—term observation of the experimental subjects, and only then - testing of a new method with the participation of terminally ill people. But the authors of the new method are optimistic. It took scientists 15 years of research work to successfully transplant artificial lungs to pigs. It may take half as much time to transfer the technology to clinical medicine.
Article by Nichols et al. Production and transplantation of bioengineered lung into a large-animal model is published in the journal Science Translational Medicine.
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