Organ transplantation can save lives, but it has problems such as long waiting times and high chances of rejection. Stanford University scientists have taken a major step toward creating new organs on demand, having secured a contract and experimental funding to 3D print a human heart and implant it into a living pig.
When a patient's organs begin to fail, often the only option is a transplant. While transplants can save lives, it's not a simple answer - donated organs are in short supply, meaning many patients die on waiting lists. Even if a matching organ is found, the recipient's immune system sees the organ's cells as foreign and attacks them, leading to rejection. Immunosuppressive drugs can prevent this from happening, but this can make the patient susceptible to other diseases.
The ideal solution would be to extract stem cells from the patient and use them to 3D print an entirely new organ. Not only can this be done whenever needed, but because they are made from the recipient's own cells, organ rejection will be a thing of the past. The technology needed to realize this vision has been steadily developing in recent years, including the ability to print blood vessels into these tissues.
Now, we have taken a major step toward this possible future. A team of Stanford University scientists has been awarded a $26.3 million federal contract from the Advanced Research Projects Agency-H (ARPA-H) to bioprint a functional human heart and implant it into live pigs to test the feasibility of such a procedure.
Mark Skylar-Scott, the project's principal investigator, said: "This is truly a moonshot-level effort, but the raw materials for bioprinting a complete and complex human organ are now ready to go. With vasculature, there is the ability to create large chunks of thick tissue that can be implanted and survive. This begins the era of organ biofabrication."
Using a bank of automated bioreactors, the team plans to grow all the cell types needed to make a human heart, including ventricular and atrial cardiomyocytes (responsible for contraction when the heart beats), nodule cells that generate electrical signals and act as natural pacemakers, cells that form Purkinje fibers (that conduct those electrical signals), smooth muscle cells, immune cells called macrophages, and blood vessel endothelial cells. These cell mixtures can then be fed into a bioprinter and used as "ink" to 3D print a fully functional human heart.
The team says the bioreactors will be able to produce billions of different cells, enough to print a heart every two weeks. The hearts will be put through the paces in the laboratory, improving them in preparation for eventual testing on live pigs, in the hope that they will keep the animals alive.
"We will practice, practice, practice with these large numbers of cells, learning all the design rules of the heart and optimizing survival and function throughout the heart for eventual implantation into pigs," Schuyler-Scott said.
While the team hopes to conduct pig experiments within the next five years, final human trials may be many years away. However, these trials are necessary proof-of-concept research on the road to bioprinting new organs using your own cells.