Bioengineered lungs successfully transplanted into pigs

Bioengineered lungs successful...
Researchers have implanted bioengineered lungs into pigs, with no medical complications
Researchers have implanted bioengineered lungs into pigs, with no medical complications
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Researchers have implanted bioengineered lungs into pigs, with no medical complications
Researchers have implanted bioengineered lungs into pigs, with no medical complications

When it comes to organ transplants, the waiting list and donor list don't quite line up, and even if a patient is lucky enough to receive the surgery, there's a chance their body may reject the foreign organ. But what if doctors could grow new organs on demand from a patient's own cells? In a major step towards this future, scientists from the University of Texas Medical Branch (UTMB) have now transplanted bioengineered lungs into pigs, with no complications arising from the procedure.

Instead of waiting for another person to offer up a spare organ, in the future patients could simply have whatever they need grown or even 3D-printed from their own cells. In recent years, scientists have managed to make strides towards this by bioengineering muscle, blood vessels, kidneys, bone marrow and skin.

Now, the UTMB researchers have implanted an entire lung into pigs, grown from their own cells. To start with, they took a lung from another animal and bathed it in a solution designed to strip out all the blood and living cells. What's left is a "scaffold" of proteins in the shape of the lung.

Next, the researchers removed a lung from each test pig, and collected cells from them. The scaffold was bathed in a tank full of a nutrient medium, and the animal's lung cells were added. Those cells spread out across the scaffold over the next 30 days to form a brand new lung ready for transplantation.

To check how well the new organ was being received, the researchers examined different groups of the pigs at different intervals – 10 hours, two weeks, one month and two months after the surgery. All of the pigs stayed healthy for the entire time, and the researchers noticed that the lungs had managed to grow the required blood vessel network by the two-week mark.

"We saw no signs of pulmonary edema, which is usually a sign of the vasculature not being mature enough," say Joan Nichols and Joaquin Cortiella, lead researchers on the study. "The bioengineered lungs continued to develop post-transplant without any infusions of growth factors, the body provided all of the building blocks that the new lungs needed."

While this study was focused on how well the bioengineered lungs would survive and grow in the host, the team didn't test how well the organ provided oxygen to the animal. The researchers say that future studies will incorporate this metric into the experiment. If it all works out, the process could be used for human implants within five to 10 years.

The research was published in the journal Science Translational Medicine.

Source: UTMB

Ralf Biernacki
This is very impressive. The main problem with grown transplants of this type has so far been vasculature---you can develop micro organoids in a nutrient solution, but a macro organ needs blood to supply oxygen and nutrients. Here the researchers cleverly eliminated the need to supply the oxygen by picking a lung as the organ---the lung cells get their oxygen directly from air, it doesn't need to be supplied by blood---quite the reverse. And apparently the lung somehow survived being starved of nutrients for two weeks, though I don't know how. What I also don't know is how the body managed to regenerate the entire vasculature of the lung---including some fairly large vessels---within these two weeks. Regeneration on that scale should not be possible in a mammal, not to mention the astonishing speed.
It's an interesting step forward, but I note that an existing lung was still required, so it doesn't address the problem of limited donors (not without invoking the liver donor sketch from Monty Python's Meaning of Life film anyway). The next big step will be the synthesis of the protein scaffold from scratch.