The human lung is quite a very complex structure. Multiple branchings here and there, complex mechanisms of gaseous exchange, and the like. This arrangement has made it challenging to design a respiratory system that can mimic the function of a healthy human lung.
But that hurdle might as well be over as a team of bioengineers have learned to solve this problem of breathing, from the most unlikely source–a lizard. The simple mechanics by which the lizard lung work, have simply amazed scientists. Could this be the answer we have been searching for? Let us find out!
What good can come from a lizard?
The lead investigator and a Wilke Family Professor in Bioengineering Celeste Nelson say “Our group is interested in understanding lung development for engineering purposes… If we understand how lungs build themselves, then perhaps we can take advantage of the mechanisms mother nature uses to regenerate or engineer tissues.”
The anatomy is quite basic, it is so basic that the lungs develop in two days. The authors describe the anole lungs as a stress ball. Their lung develops in a hollow, long structure surrounded by a continuous layer of smooth muscle. The cells lining the lungs secrete fluid that inflates the lungs, like the balloon. The pressure causes the smooth muscles to tighten, increases the surface area of the lungs, and forms fluid-filled sacs that cover the lungs. Just like that, we have brand new lungs! Gaseous exchange can now commence in earnest.
Pertinent to say at this point that before this research team commenced this experiment in lizards they had already studied the respiratory system of other vertebrates like mice and birds. They noticed that the respiratory systems of birds were quite complex and different from that of humans. Replicating the avian style of respiration in humans will be truly scientifically challenging.
This obstacle prompted Nelson to go back to books, searching for which animals had respiratory systems that were evolutionarily linked to that of humans. Lo and behold, there it was: it had been the reptile, the whole time.
Palmer Ph.D. in chemical and biological engineering who was the first to organize this study said “We were curious if we could learn anything about the basics of lung development from studying such a simple lung… the lizard lung develops using a very physical mechanism… a cascade of pressure-induced tensions and pressure-induced buckling.”
To recreate the anole lizard’s lung, they first designed a computer model of the lung and its physics. Then using Ecoflex, a silicone substance used for makeup in movies. They lined the Ecoflex with 3D printed smooth muscle to reflect the setting in an actual lizard. Though they encountered several difficulties, in the end, the test mirrored the actual lizard lung.
If scientists and biotechnologists can learn how to cut corners and still produce a functional lung like that of the anole lizard, it could bring hope to a lot of areas in pulmonology we thought was a dead end. The speed and simplicity are just remarkable, if this is replicated in humans, the incidence of unmet lung transplants demand could reduce.
It will usher in more study about other reptile tissue that develops just as fast, who knows? There might be a breakthrough somewhere.
This experience has taught research that answers could be found in the most unlikely places or animals. This is surely the breakthrough we needed.