By the time 10-year-old Sarah Murnaghan got a lung transplant last week, she’d been waiting for months, and her parents had sued to give her a better shot at surgery.
Her cystic fibrosis was threatening her life, and her case spurred a debate on how to allocate donor organs. Lungs and other organs for transplant are scarce.
But what if there were another way? What if you could grow a custom-made organ in a lab?
It sounds incredible. But just a three-hour drive from the Philadelphia hospital where Sarah got her transplant, another little girl is benefiting from just that sort of technology. Two years ago, Angela Irizarry of Lewisburg, Pa., needed a crucial blood vessel. Researchers built her one in a laboratory, using cells from her own bone marrow. Today the 5-year-old sings, dances and dreams of becoming a firefighter — and a doctor.
In North Carolina, a 3-D printer builds prototype kidneys. In several labs, scientists study how to build on the scaffolding of hearts, lungs, livers and kidneys of people and pigs to custom-make implants.
Here’s the dream scenario: A patient donates cells. A lab uses them, or cells made from them, to seed onto a scaffold that’s shaped like the organ he needs. Then, says Dr. Harald Ott of Massachusetts General Hospital, “we can regenerate an organ that will not be rejected [and can be] grown on demand and transplanted surgically.”
A few weeks ago, a girl in Peoria, Ill., got an experimental windpipe that used a synthetic scaffold covered in stem cells from her own bone marrow.
Dozens of people are thriving with experimental bladders made from their cells, as are more than a dozen who have urethras made from their own bladder tissue.
Surgeons can use a patient’s own cells, processed in a lab, to repair cartilage in the knee. Burn victims are treated with lab-grown skin.
In 2011, it was Angela Irizarry’s turn to wade into the field of tissue engineering.
Angela was born in 2007 with a heart that had only one functional pumping chamber, a potentially lethal condition that leaves the body short of oxygen.
Doctors took bone marrow from Angela and extracted certain cells, seeded them onto a 5-inch-long biodegradable tube, incubated them for two hours, and then implanted the graft into Angela to grow into a blood vessel.
The researchers in charge of Angela’s study had been putting the lab-made blood vessels into people for nearly a decade in Japan before they realized that they were completely wrong in their understanding of what was happening inside the body.
“We’d always assumed we were making blood vessels from the cells we were seeding onto the graft,” said Dr. Christopher Breuer, now at Nationwide Children’s Hospital in Columbus, Ohio. But then studies in mice showed that, in fact, the building blocks were cells that migrated in from other blood vessels. The seeded cells actually died off quickly.
Seeded cells can act as beacons that summon cells from the recipient’s body, said William Wagner, director of the McGowan Institute for Regenerative Medicine at the University of Pittsburgh.
So far, the lab-grown parts implanted in people have involved fairly simple structures, notes Anthony Atala of Wake Forest University whose lab has made scaffolds for noses and ears.
His lab is using a 3-D printer to make miniature prototype kidneys and other structures for research. The printer puts down a gel-like biodegradable scaffold plus a mixture of cells to build a kidney layer by layer.
Another organ-building strategy starts with an organ, washes its cells off the inert scaffolding that holds cells together, and then plants that scaffolding with new cells.
Dr. John LaMattina of the University of Maryland School of Medicine is using the approach to build livers. One goal of that process is humanizing pig organs for transplant, by replacing their cells with human ones.
How long until doctors start testing solid organs in people? LaMattina figures five to 10 years might be about right for human studies of his specialty, the liver.
“I’m an optimist,” he adds. “You have to be an optimist in this job.”