Eyeing Growing Retinas with Stem Cells

The outermost layer primarily contained photoreceptors (red), whereas the middle and inner layers harbored intermediary retinal neurons and ganglion cells (green), respectively. This particular arrangement of cells is reminiscent of what is found in the back of the eye.

Did anybody else find it weird that Geordi LaForge had to have a machine to replace his eyes? Throughout the entire Star Trek: TNG series, Geordi’ VISOR picked up infrared and ultraviolet wavelengths and transported the signals to his brain. While this jumble of information allowed him to “see,” picking up wavelengths in the normal visual range somehow eluded futuristic medicine. Even later on, several movies in, his eyes were still machines.

Why couldn’t they just fix his old eyes? Or better yet, why couldn’t they just grow him new ones?

The obvious answer is that because then there wouldn’t be a character with cool seeing abilities and a giant piece of metal on his face. Having a perfectly normal guy walking around with replacement eyes would be boring. But are machines really the future of curing disabilities?

There is plenty of research out there that says, “maybe.” Some progress has been made using photoreceptor implants and connecting them to the brain. The individual light-sensing cells on such chips aren’t small enough to create much resolution, but patients have been able to make out large objects.

Now, however, there are some promising results from the other side of the fence. Scientists at the University of Wisconsin have managed to use stem cells to grow retinal cells that form layers just like an eye does in normal human development.

Starting with a simple blood draw from the patient, the scientists wipe its slate clean in order to create induced pluripotent stem (iPS) cells. They then nudge these blank pages towards forming retinal tissues. For the first time, David Gamm, pediatric ophthalmologist and senior author of the study, has sown that these tissues have the capacity to form layers of cells that possess the machinery that could allow them to communicate information.

As you may have guessed already, a typical human eye has layers of specialized cells. Light-sensitive photoreceptor cells in the retina along the back wall of the eye produce impulses that are ultimately transmitted through the optic nerve and then to the brain, allowing you to see, for example.

Of course, growing a working human retina is a long, long ways off. I mean, they couldn’t even do it in Star Trek. But the technique does hold promise for growing tissues that can be used in other studies, like using them to test drugs and study degenerative diseases of the retina. Or perhaps if they can’t grow an entire eye, a graft of some healthy retinal cells could help repair retinal damage.

And now to give the rest of the hard-working researchers their due, other members of the research team include:

  • Kyle Wallace, Amelia Verhoeven, Jessica Martin, Lynda Wright, Wei Shen, Elizabeth Capowski and Enio Perez, of the Waisman Center
  • Sarah Dickerson and Michael Miller of Cellular Dynamics International
  • E. Ferda Percen of the Faculty of Medicine, Gazi University, Ankara, Turkey
  • Xiufeng Zhong and Maria Canto-Soler, of the Wilmer Eye Institute at Johns Hopkins Univerity
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About bigkingken

A science writer dedicated to proving that the Big Ten - or the Committee on Institutional Cooperation, if you will - is more than athletics.
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