Brown University research on ways to prevent blindness among programs threatened by Trump cuts
Brown University
In a study published
in the journal ACS Nano and supported by the National Institutes of
Health, the research team showed that nanoparticles injected into the retina
can successfully stimulate the visual system and restore vision in mice with
retinal disorders. The findings suggest that a new type of visual prosthesis
system in which nanoparticles, used in combination with a small laser device
worn in a pair of glasses or goggles, might one day help people with retinal
disorders to see again.
“This is a new type of retinal prosthesis that has the
potential to restore vision lost to retinal degeneration without requiring any
kind of complicated surgery or genetic modification,” said Jiarui Nie, a
postdoctoral researcher at the National Institutes of Health who led the
research while completing her Ph.D. at Brown. “We believe this technique could
potentially transform treatment paradigms for retinal degenerative
conditions.”
Nie performed the work while working in the lab of Jonghwan Lee, an associate professor in Brown’s School of Engineering and a faculty affiliate at Brown’s Carney Institute for Brain Science, who oversaw the work and served as the study’s senior author.
EDITOR'S NOTE: Read more about Musk-Trump cuts to medical research at Brown HERE.
Retinal disorders like macular degeneration and retinitis pigmentosa affect millions of people in the U.S. and around the world. These conditions damage light-sensitive cells in the retina called photoreceptors — the “rods” and “cones” that convert light into tiny electric pulses. Those pulses stimulate other types of cells further up the visual chain called bipolar and ganglion cells, which process the photoreceptor signals and send them along to the brain.
This new approach uses nanoparticles injected directly into
the retina to bypass damaged photoreceptors. When infrared light is focused on
the nanoparticles, they generate a tiny amount of heat that activates bipolar
and ganglion cells in much the same way that photoreceptor pulses do. Because
disorders like macular degeneration affect mostly photoreceptors while leaving
bipolar and ganglion cells intact, the strategy has the potential to restore
lost vision.
In this new study, the research team tested the nanoparticle
approach in mouse retinas and in living mice with retinal disorders. After
injecting a liquid nanoparticle solution, the researchers used patterned
near-infrared laser light to project shapes onto the retinas. Using a calcium
signal to detect cellular activity, the team confirmed that the nanoparticles
were exciting bipolar and ganglion cells in patterns matched the shapes
projected by the laser.
The experiments showed that neither the nanoparticle
solution nor the laser stimulation caused detectable adverse side effects, as
indicated by metabolic markers for inflammation and toxicity. Using probes, the
researchers confirmed that laser stimulation of the nanoparticles caused
increased activity in the visual cortices of the mice — an indication that
previously absent visual signals were being transmitted and processed by the
brain. That, the researchers say, is a sign that vision had been at least partially
restored, a good sign for potentially translating a similar technology to
humans.
For human use, the researchers envision a system that
combines the nanoparticles with a laser system mounted in a pair of glasses or
goggles. Cameras in the goggles would gather image data from the outside world
and use it to drive the patterning of an infrared laser. The laser pulses would
then stimulate the nanoparticles in people’s retinas, enabling them to
see.
The approach is similar to one that was approved by the Food
and Drug Administration for human use a few years ago. The older approach
combined a camera system with a small electrode array that was surgically
implanted in the eye. The nanoparticle approach has several key advantages,
according to Nie.
For starters, it’s far less invasive. As opposed to surgery,
“an intravitreal injection is one of the simplest procedures in ophthalmology,”
Nie said.
There are functional advantages as well. The resolution of
the previous approach was limited by the size of the electrode array — about 60
square pixels. Because the nanoparticle solution covers the whole retina, the
new approach could potentially cover someone’s full field of vision. And
because the nanoparticles respond to near-infrared light as opposed to visual
light, the system doesn’t necessarily interfere with any residual vision a
person may retain.
More work needs to be done before the approach can be tried
in a clinical setting, Nie said, but this early research suggests that it’s
possible.
“We showed that the nanoparticles can stay in the retina for
months with no major toxicity,” Nie said of the research. “And we showed that
they can successfully stimulate the visual system. That’s very encouraging for
future applications.”
The research was funded by the National Institutes of
Health’s National Eye Institute (R01EY030569), the China Scholarship Council
scholarship, the Saudi Arabian Cultural Mission scholarship, and South Korea’s
Alchemist Project Program (RS-2024-00422269). Co-authors also include
Professor Kyungsik Eom from Pusan National University, Brown Professor Tao Lui,
as well as Brown students Hafithe M. Al Ghosain, Alexander Neifert, Aaron
Cherian, Gaia Marie Gerbaka, and Kristine Y. Ma.
