Pitt research team sets sights on human eye transplant
An international team of researchers based at the University of Pittsburgh has begun a once-unthinkable campaign to transplant the human eye and restore sight for tens of millions of people.
Though they won't guarantee success, doctors say they could spark a global revolution in eye care and deliver hope to victims of glaucoma, macular degeneration and other permanent vision loss — even those blind since birth. Clinical trials could start in a decade under a best-case scenario, although the group will need millions of dollars that it has not secured.
“We believe it's an extremely audacious goal,” said Dr. Vijay Gorantla, a co-principal investigator and founder of the Audacious Restorative Goals in Ocular Sciences Consortium that spans 13 institutions from Paris to San Diego.
Still, he said, “I believe we will be successful. It's just a matter of time.”
About 20 percent of blindness is neither preventable nor curable, according to the American Academy of Ophthalmology. Doctors have refined laser surgery and other targeted procedures to ease a range of vision problems, but an eyeball transplant has remained elusive.
Historical medical records show the sensitive organ has confounded doctors since the mid-1800s, when early transplant attempts fell short.
Doctors tried several hundred more since then, in animals and people, Gorantla found in his review of the records. Each effort appears to have failed.
Researchers believe that's because their predecessors did not have a complete handle on the science involved, including the body's tendency to reject transplanted organs without help from immune-suppressing drugs.
‘Nobody thought it could be done'
An eye is more complicated than other transplants because of the mysterious optic nerve, a connection behind the eyeball that ties it into the body. Unlike other tissue, the optic nerve typically does not regenerate itself once it's damaged, leaving researchers at a loss for how to plug a transplanted eye into a recipient's brain.
“This was never technically possible. The problem is if you take the eye of a donor and put it into a recipient, those nerve fibers from the donor are not going to reconnect,” said Larry Benowitz, a Harvard University Medical School professor and contributor to the transplant project.
But his discoveries since the mid-1990s and related work by Dr. Jeffrey Goldberg at the University of California, a project contributor, illustrate how doctors might stimulate the optic nerve to grow and forge a connection — with a new host brain.
Their revelations, combined with better anti-rejection drugs and microsurgery to connect tiny blood vessels, could make possible a functional eye transplant, project collaborators agreed in mid-2013.
A core group including Gorantla, Benowitz and Goldberg won $1.25 million in grants last year from the Department of Defense, which wants to alleviate eye injuries among soldiers wounded in action.
As many as 40 percent of blast injuries damage the eyes, according to the department. Researchers hope its initial three-year support will inspire multimillion-dollar grants from other sources, including private foundations.
“We view it as analogous to the moon shot in the early '60s. When (President John F.) Kennedy said we would send a man to the moon before the end of the decade, it was audacious. Nobody thought it could be done,” said project co-principal investigator Dr. Joel Schuman, ophthalmology chairman at Pitt and director of its Louis J. Fox Center for Vision Restoration.
The center is helping to pay for the transplant project, which Fox said could cost as much as $25 million before reaching human trials.
“We're working with some of the smartest, brightest people, not only in ophthalmology but in medicine,” said Fox, a Pitt alumnus and benefactor who urged the lead researchers to collaborate on the project.
Gorantla, a reconstructive transplant specialist at UPMC, began floating the concept in ophthalmology circles several years ago.
Even if the work does not deliver a viable eye transplant within a decade, collaborators and outside observers agree, the push should inspire incremental innovations to strengthen vision care. The group has enlisted a cross-section of specialists to tackle nuances: from preserving the retina to preventing transplant rejection.
“Even if you can't replace the whole eye, just learning more about the retina and nerve tissues — that's got to help with all these neurodegenerative problems,” said Dr. Julia A. Haller, ophthalmologist-in-chief at Wills Eye Hospital in Philadelphia. She is not involved with the research.
At Johns Hopkins Wilmer Eye Institute in Baltimore, Dr. Esen Akpek said that simply keeping eye tissue vital long enough to be moved could be more challenging than the surgery.
“It's not that technically it's not feasible. It's how do you keep the tissue alive during the transplantation of the tissue — and how do you regenerate the cells that die off at the time of harvesting?” said Akpek, who is not sure a transplant is possible, at least for now.
Still, patients coping with blindness hold out hope. About 180 million people worldwide are blind or otherwise visually disabled, according to the ophthalmology academy. More than 6.6 million people in the United States have a visual disability.
Diane Faust, 52, of West Mifflin is one of them. The degenerative disease retinitis pigmentosa claimed much of her vision during the past 18 months.
“Your independence, to a large degree, has been taken. Work opportunities are now much narrower than they were before, without specialized training. There's a lot of things in your life that change when your vision is taken away,” said Faust, who had to quit her job as a business manager but has returned to school.
Though researchers might not be able to cure every case of blindness, she said, limited progress could change lives.
“There are so many people who have so many things to contribute,” Faust said.
Adam Smeltz is a Trib Total Media staff writer.