Creating lungs “from scratch”

Millions of people suffer from organ failure; 15 million people need lung transplants alone. But the organ transplant system currently has nowhere near the number of organs needed to help patients suffering from organ failure. Particularly when it comes to lungs, the current available treatments are not enough to help people breathe easily.

Erica Comber, a Ph.D. student in the Department of Biomedical Engineering (BME), is part of Carnegie Mellon’s Bioengineered Organs Initiative. And the great thing about the Initiative, according to Comber, is that its researchers are all working toward the goal of handling, and eliminating, the organ deficit. And sometimes this means not only obtaining organs for patients—but making them.

There are many ways to make a lung, however, and with so many possible approaches, where do you even start?

That’s exactly the question that Comber and her advisor Keith Cook, professor of biomedical engineering, addressed in a recent, first-of-its-kind paper, outlining several different approaches to creating human lungs from scratch.

“There’s a huge divergence of approaches in this field, and no one approach is necessarily more valid than another,” says Comber. “It’s about using different techniques to try to accomplish the same goal and then learning from each other.”

It’s about using different techniques to try to accomplish the same goal and then learning from each other.

Erica Comber, Ph.D. Student, Biomedical Engineering

By identifying important parameters to consider and describing the ways that one could approach this problem, the paper, published in Translational Research, will act as a guide to future researchers looking to create human organs de novo, or “from scratch.”

The paper discusses a few different approaches to addressing the problem of de novo organ creation. Approaches span from using existing biological organs as a starting point—by removing cells from existing organs and recellularizing them with the patient’s own cells—to generating completely artificial organs.  

Comber’s work is a hybrid of those two approaches. This paper outlines approaches to her work, which is to create de novo artificial lungs. Using natural materials such as collagen type 1, Comber makes artificial lungs that can be housed within the chest and designed in geometries that optimize how much oxygen and carbon dioxide can be cycled in and out of the circulatory system.

Existing artificial lungs are largely stopgap measures, and a plethora of complications can arise from their use. The average duration of use is about a week, and a patient’s chance of surviving the therapy shrinks the longer they’ve been supported. Artificial lungs made from polymers can also cause blood to form clots on the surface, which is why they fail, and have to be frequently replaced. Drugs used to slow blood clots can also cause patients to bleed. Each time artificial lungs are replaced, the patient can be exposed to infection risk.

De novo lung biofabrication could be the key to solving these issues. By designing artificial lungs that can be permanently attached to the circulatory system, and that can be created in geometries that approximate lung geometries but optimize for gas exchange, researchers could remedy the blood clotting and bleeding risk associated with existing artificial lungs.

“We have a long way to go,” says Comber, “but we expect to see these de novo organs commercially available in our lifetime.”

Comber is co-advised by Cook and Adam Feinberg, associate professor of biomedical engineering and materials science and engineering. Co-authors on this paper include Cook, and BME faculty Xi Ren and Rachelle Palchesko Simko, and BME postdoctoral researcher Wai Hoe NG.