A Transformation in Transplantation

From Minnesota Alumni Magazine Spring 2016

3D bioprinting is a "game-changer" in regenerative medicine.

By Meleah Maynard

sp2016_atransformationintransplanationAngela Panosklatsis-Mortari at the U's 3D Bioprinting Facility

The idea of printing body parts for human application sounds like science fiction. But transplant specialist Angela Panoskaltsis-Mortari, a professor of pediatrics and medicine at the University of Minnesota, believes it’s likely we will see production of at least basic parts—bones, skin, tendons, noses, ears, and blood vessels—on three-dimensional bioprinters within the next decade. Further into the future, she predicts 3D bioprinting may also make it possible to create more complex organs such as livers, kidneys, and hearts.

“This is a game changer that’s as revolutionary to medicine as the internet was to communication,” says Panoskaltsis-Mortari, who heads the University’s 3D Bioprinting Facility, which opened in July. “Just like 3D printing changed manufacturing, 3D bioprinting will make it possible for surgeons to transplant an organ printed to the exact size and shape for the patient.” Researchers hope they will eventually be able to make some parts using an individual’s own cells, eliminating the problem of transplant rejection. Eventually, the technology could help ease problems like long waiting lists for organs and struggles to find matching donors. “It doesn’t mean that the whole organ donor system would go away,” she explains. “But this would be an alternative for people who could not get an organ they needed or a body part that can’t be transplanted currently from a deceased or living donor.”

Unlike traditional 3D printing, which has been around since the mid-1980s, primarily for making manufacturing prototypes. Bioprinting uses organic material rather than wax or plastic. Using a 3D image as its guide, the print head slowly scrolls back and forth laying down thin layers of a special type of ink that can be combined with living cells and biomaterials, such as collagen and elastin.

Researchers are already using conventional 3D printing technology to create models of hearts and other organs for teaching purposes. They also use models to explain procedures to patients, evaluate surgical procedures, and help create medical devices. And patients are currently using 3D printed prosthetic arms, orthotics, and braces. Bioprinting, though, is still in early stages. Panoskaltsis-Mortari explains that researchers are using 3D bioprinting to make small models of tissue that pharmaceutical companies are experimenting with to test drugs. And it is already possible to print biocompatible scaffolds to help support organs, keep an airway open, or serve as a guide for nerves that have been severed.

Last year, a national team led by University of Minnesota professor of mechanical engineering Michael McAlpine developed the first 3D printed guide to help regrow the sensory and motor functions of injured nerves. Implanted in a lab rat with biochemical cues to aid in nerve regeneration, the guide improved the rat’s ability to walk within weeks. McAlpine’s hope is to one day create custom nerve guides for patients whose nerves have been damaged by injury or disease.

For years, Panoskaltsis-Mortari had been thinking about the possibilities 3D bioprinting could offer patients. Then, last year, the U.S. technology startup BioBots selected her lab as one of 20 research facilities worldwide to receive a 3D bioprinter at a deeply discounted price. The new printer made it possible for her team to produce a piece of biocompatible esophagus that will soon be transplanted into a pig. Having the ability to successfully transplant a bioprinted portion of esophagus, trachea, or bronchus could dramatically change the way doctors treat patients with congenital defects or advanced disease, she says.

Researchers are also working on ways to bioprint specific cells on demand, such as skin cells for burn patients or bone for patients with severe bone damage. For now, though, researchers like Panoskaltsis-Mortari have many questions to answer. How thick can printed parts be? What kinds of biocompatible materials can hold sutures? How will 3D bioprinted parts and tissues support cell growth? And how will bioprinted parts function in the long-term?

It may be decades, but she believes that eventually the University’s 3D Bioprinting Facility, along with a handful of others around the country, will be capable of producing even complex organs for transplant. Still, much remains to be done. “Even when we are ready, before we can get approval, organs must be tried in large animals like pigs and sheep,” she explains. Once the transplants are successful on animals, it may be possible to do limited human transplants, mostly likely for patients with no other options who might quality for compassionate use. “We’ve got to ensure that bioprinted parts are going to be functional over the long term or be sure that in some cases they can be used as a bridge between a conventional transplant.”

Since its inception, the 3D Bioprinting Facility has acquired two more bioprinters—another from BioBots and one that McAlpine and some of his mechanical engineering students made. An additional laser 3D bioprinter is currently being built and should be operational in a few months. The laser will allow doctors to print one cell at a time and has been used to print new skin and bone directly on rats’ wounds in the lab. “It’s like when you see a sci-fi movie and someone puts their injured arm in a machine and it comes out fine again,” Panoskaltsis-Mortari says, explaining that the machine would use a scanned 3D image of the arm to guide the printer as it rebuilt the injured area.

In addition to her team, researchers in many disciplines on campus will use the new lab, including biomedical engineers, biologists, stem cell scientists, surgeons, computer engineers, biophysicists, and many others. “There’s a lot of interdisciplinary work being done here beyond making organs,” she says. “There is potential to generate knowledge and understand so many meaningful things, like cell behavior and how well we can approximate the natural environment that a cell finds itself in in the body. Up until now we’ve only been able to study cells in two-dimensional environments even though cells normally interact in a 3D environment in our bodies. This could change a lot of what we know.”

MINNESOTA ALUMNI MAGAZINE, Spring2016

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