At a Tampa eye lab, a discovery involving retinas puts big advances in sight

A scientist's discovery of a way to preserve and revive human retinas could help with eye diseases and, far in the future, retina transplants.
Mitch McCartney of the Lions Eye Institute in Ybor City called the work on retinas an “important first step” toward transplants. LUIS SANTANA   |   Times
Mitch McCartney of the Lions Eye Institute in Ybor City called the work on retinas an “important first step” toward transplants.LUIS SANTANA | Times
Published November 29 2015
Updated November 30 2015

A discovery made in a Tampa laboratory could one day help millions of people regain their vision.

Working at the Lions Eye Institute last summer, Daniel Lindgren, of the Nevada-based research firm OcuScience, found a way to preserve retinas from human donors — and bring them back to life.

Now he's working to patent the technology.

The development is significant because donated retinas have been considered too perishable for functional research, Lindgren said. Most studies have used animals.

"This creates a brand new avenue for doing that work," he said.

That's not the only reason Lindgren is excited. He says the finding could help pave the way for retina transplants — a procedure that has thus far been impossible.

The retina is the inner layer of the eyeball. It contains cells known as photoreceptors that convert light into electrical impulses, which are sent to the brain to be interpreted as images.

Researchers haven't had much success using donated human retinas to understand the function of the eye.

The reason?

"It suffers postmortem effects very quickly," said Mitch McCartney, the scientific director at Lions Eye Institute, a well-known ocular research center in Ybor City that boasts the world's largest eye bank..

Lindgren wanted to find a way to change that.

He took a particular interest in technology developed at Washington University in St. Louis that could revive animal retinas. He licensed it, he said, and started searching for a place to try it on human specimens.

That's when he connected with the Lions Eye Institute.

The partnership made sense, McCartney said.

"We made special arrangements with our recovery staff to have (retina) tissue in the laboratory within four hours of the time of death," he said.

Lindgren and his team began their research in July.

After some trial and error, they were able to fine-tune a method for transporting human retinas in a nutrient-rich solution. The system maintains a constant temperature and keeps each tissue sample isolated.

They then "revived" the retinas with an instrument known as an electroretinogram, or ERG, which flashes light on the retina and records its response using electrodes. The sample retinas weren't technically seeing anything, Lindgren pointed out, because they weren't attached to a brain. But they were able to send electrical impulses.

"The retina is a flatline after death," he said. "Using our methods, we are able to regain its function."

He likened it to the procedure for transplanting human hearts.

"The heart stops beating in the dead person; it is recovered, kept on ice and flown to wherever it needs to go," he said. "Then, the doctors have to put it in (the transplant recipient) and restart it."

The team returned to Tampa in late August to repeat the experiment. Again, it was a success.

Lindgren says he hopes the method will soon enable researchers to test drugs for eye diseases on human retinas. That could help scientists cure age-related macular degeneration, a disease that affects an estimated 15 million adults in the United States, he said.

"Having the opportunity to use real human tissue to test the effect of a drug is a significant advantage over using an animal," he said. "It's a more precise response."

The research wouldn't be limited to diseases of the eye, he added.

"The eye is the window to the brain," he said. "We'll be able to access and look at neurologic drugs to see what their effect is."

What's more, McCartney called the work "an important first step" toward retina transplants.

"That's something that's not going to happen in the near future," he said. "But this gives us another tool to help explore that."

Contact Kathleen McGrory at kmcgrory@tampabay.com or (727) 893-8330. Follow @kmcgrory.

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