Scientists Reverse Congenital Blindness in Mice

Recent studies may lead the way for improved therapies for retinal dystrophy in humans.

Scientists at the National Eye Institute (NEI) have recently reversed congenital blindness in mice. The breakthrough methodology could potentially lead to better treatment for eye impairments in humans.

The recent research by scientists involves changing supportive cells in retinal tissue. The cells of interest are known as Muller glia (MG), in which researchers developed a method to reprogram the retina cells into photoreceptor cells known as rods, reports Times Now.

Mammalian eyes contain rods and cones, both carrying out separate functions imperative for vision. Rods are receptor cells in the eye. According to Thomas N. Greenwell, Ph.D., NEI program director for retinal neuroscience, rods allow us to see in low light, “but they may also help preserve cone photoreceptors, which are important for color vision and high visual acuity.”

He adds that “cones tend to die in later-stage eye diseases. If rods can be regenerated from inside the eye, this might be a strategy for treating diseases of the eye that affect photoreceptors,” according to Times Now.

The study, as reported in the science journal, Nature, involved extracting MG from mice and employing gene-switching to elicit changed behavior in the cells. The scientists turned on the protein beta-catenin and injected the mice’s eyes with “factors that encouraged the newly divided cells into rod photoreceptors,” reports Science Daily.

Remarkably, they found that the rod photoreceptors derived from their experiments appeared structurally the same as normal photoreceptors. As the next step, researchers plan to see if the experiment can be duplicated on human retinal tissue.

Damage to human retinal tissue is typically caused by genetic factors according to U.S. National Library of Medicine. Various mutations over 30 genes can cause cone-rod dystrophy and produce symptoms of impaired vision that can begin in childhood and worsen over time.

The dystrophy of rods is problematic because retina tissues are neurons, and mammalian neuron tissue do not multiply. This is not the same throughout the animal kingdom according to Science Daily. For instance, scientists have long studied zebrafish, because their MG can multiply in response to trauma and turn into photoreceptors and other retinal neurons. Through this mechanism, zebrafish can regain vision after a trauma.

“Their findings advance efforts toward regenerative therapies for blinding diseases such as age-related macular degeneration and retinitis pigmentosa,” the researchers said in Science Daily.

Chen’s lab is further reported to be conducting “behavioral studies to determine whether the mice have regained the ability to perform visual tasks.” Following these tests, Chen will then see if the techniques work on human retinal tissue in culture.

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