Stem cells are a basic building block of the body and a core component of regenerative medicine. They can be converted to generate specialized cells that perform different jobs, like building bone, regrowing heart muscle—or forming the cornea. It’s believed that they lead to more successful outcomes when used as alternatives to transplantation, because the body is less likely to reject them. that the only option to restore her vision was to undergo corneal transplantation. Each year, more than 40,000 corneal transplants are performed in the United States, and about half fail within 10 years. Martha is lucky—the transplants she received are still going strong. Her vision is now “pretty good,” she says, though she still takes daily medication to limit complications. In thinking about the people who aren’t so fortunate, Jim’s inquisitive mind whirred. Could there be a better way to treat this kind of blindness?
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body harbor stem cells. A light bulb suddenly turned on. “We could grow these stem cells and then convert them into corneal cells,” Jim remembers realizing. In other words, they could use adult stem cells to regrow a healthy cornea. Stem cells are a basic building block of the body and a core component of regenerative medicine. They can be converted to generate specialized cells that perform different jobs, like building bone, regrowing heart muscle—or forming the cornea. It’s believed that they lead to more successful outcomes when used as alternatives to transplantation, because the body is less likely to reject them. Martha set to work with donor tissue, looking for stem cells near the cornea that had the potential to become corneal cells. In 2005, she found them. Over the following years, the Funderburghs and their colleagues in the lab learned to differentiate stem cells into functional corneal cells. For the first time, these cells could make transparent corneal tissue in a laboratory dish. When the tissue was implanted into an animal eye, it remained transparent, just as it should. The solution wasn’t perfect, though: the tissue wasn’t strong or thick enough to be a substitute for a human cornea. The lab began to explore ways to produce a bigger, stronger, bioengineered cornea. “Then the idea occurred to us: Maybe we don’t have to build a whole new tissue,” Jim
In other words, they could use adult stem cells to regrow a healthy cornea.
he Funderburghs arrived
at the University of Pittsburgh in 1999, drawn by the opportunity to translate Jim’s research into potential treatments. He was named associate director of the Louis J. Fox Center for Vision Restoration, a nationally regarded comprehensive research and clinical program dedicated to ocular regenerative medicine. There, Jim established the Corneal Cell Biology Lab. Martha, with decades of corneal research under her belt, serves as lab manager. The researchers went to work investigating alternatives to corneal transplants. They started by brainstorming what type of tissue could mimic a donated cornea. Efforts to grow corneal cells in the lab weren’t panning out—they couldn’t get them to create the transparent tissue that makes up the cornea. Then, in a seminar in 2002 at Pitt’s McGowan Institute for Regenerative Medicine, the scientists learned that most tissues in the
says. “Maybe we can just put those stem cells directly into an eye and they would fix the scarring problem. To which everyone kind of rolled their eyes and said, ‘Yeah, right.’” Amazingly, however, it worked. When injected into the cornea, the stem cells produced healthy corneal tissue. More importantly, in the presence of stem cells, the vision-reducing, opaque scar tissue gradually disappeared and was replaced by normal, transparent corneal tissue. “I believe that the stem cells may be activating a potential present in our body that allows organs to regenerate on their own,” explains Jim. “We are very focused on finding more about this ‘biological switch’ that might control our ability to regenerate damaged tissue. Being able to induce our own bodies to heal themselves would transform medicine.” The research was published in the journal Stem Cells. It took years of hard work to get there, but it was just the beginning.
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n 2011, Jim Funderburgh had just finished delivering a presentation on his lab’s findings to an international conference when he and his team made a connection that would expand the possibilities of their work. They were approached by Virender Singh Sangwan, a professor and ophthalmologist from the L V Prasad Eye Institute in Hyderabad, India. “We were saying that stem cell therapy was working really well and we were kind of wondering where to go with this,” Martha says. “And he said, ‘We’ve got a million people who need this.’” With Sangwan was Sayan Basu, an ophthalS U M M E R
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