Swedish Researchers Successfully Implant 3D Printed Human Cartilage Cells in Mice

Slowly, little by little, we’re getting closer to the day that many still doubt will ever come: the day that scientists 3D print a working human organ and successfully implant it into a living human being. That day is still a while off, but researchers have now shown that it is in fact possible to 3D print tissue that can survive and grow within animals. So far, it’s been 3D printed blood vessels that have been implanted into animals – rhesus monkeys in December and mice earlier this month – but another breakthrough comes today as researchers from two Swedish universities announce that they have successfully gotten 3D printed human cartilage cells to survive and grow inside an animal.

Dr. Paul Gatenholm is a professor of biopolymer technology at Chalmers University of Technology. He’s already a pioneer in bioprinting, and he led the team, consisting of researchers from Chalmers and Sahlgrenska Academy, that used a CELLINK bioprinter to 3D print a construct formed from hydrogel mixed with human cartilage cells. After it was printed, the construct was immediately implanted in mice.

While this wasn’t the first time Dr. Gatenholm has successfully implanted cartilage in mice, this time his team took a further step forward. Not only did the cartilage tissue survive and grow, it vascularized, meaning that it formed its own blood vessels. Furthermore, the fact that it was implanted into the mice immediately after printing was significant – previous studies involved growing the cartilage in the lab before implantation.

Illustration of the formation of blood vessels in bioprinted tissue [Image: Philip Krantz]

“What we see after 60 days is something that begins to resemble cartilage. It is white and the human cartilage cells are alive and producing what they are supposed to,” said Lars Kölby, senior lecturer at Sahlgrenska Academy and specialist consultant with the Department of Plastic Surgery at Sahlgrenska University Hospital. “We have also been able to stimulate the cartilage cells by adding stem cells, which clearly promoted further cell division.”

The 3D printed scaffolds are examined after 14 days of implantation

The research was published in a study entitled “In Vivo Chondrogenesis in 3D Bioprinted Human Cell-laden Hydrogel Constructs,” which you can access here. Additional authors include Thomas Möller, Matteo Amoroso, Daniel Hägg, Camilla Brantsing, Nicole Rotter, Peter Apelgren, and Anders Lindahl.

According to Kölby, much of the project’s success was due to the collaboration between scientists of different disciplines.

“Often, it is like this: we clinicians work with problems and researchers work with solutions,” he said. “If we can come together, there is a chance of actually solving some of the problems we are wrestling with – and in this way, patients benefit from the research.”

Dr. Gatenholm cautions that people shouldn’t get overly excited – no one is going to be 3D printing and implanting a working heart tomorrow, or even next year. This study shows that 3D printed stem cells are capable of growing into cartilage inside the body, which is a huge success for the team and the entire field of bioprinting and tissue engineering, but it’s still a relatively small step overall.

“With what we have done, the research has taken a step forward towards someday, we hope, being able to bioprint cells that become body parts for patients,” he said. “This is how you have to work when it comes to this kind of pioneering activity: one small step at a time. Our results are not a revolution – but they are a gratifying part of an evolution!”

Discuss in the 3D Printed Cartilage forum at 3DPB.com.