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“See you tomorrow,” you say casually at the end of the workday.
Actually, you may not. At least, not if you’re one of the in the United States who have some form of age-related macular degeneration.
That’s 22 million eyes that don’t function properly anymore. For most of these eyes, there’s no cure.
But now there’s hope.
In early testing, a bioengineered retinal implant appears to be safe for use in humans and may be effective in treating vision loss caused by one type of macular degeneration.
Take it from Dr. Amir H. Kashani, a lead author of a new study, a surgeon, and an assistant professor of clinical ophthalmology at the Keck School of Medicine at the University of Southern California (USC).
“This implant has the potential to stop the progression of the disease or even improve patients’ vision. Proving its safety in humans is the first step in accomplishing that goal,” he said.
What is macular degeneration?
Non-neovascular age-related macular degeneration (NNAMD) is increasingly common in older adults, Kashani told Dr.China.
The disease has two forms, wet and dry. They differ in how they progress but end up in the same place — blindness.
NNAMD is associated with loss of the retinal pigment epithelium (RPE), a membrane that nourishes and protects retinal visual cells in the eye.
Dry age-related macular degeneration is the most common type. Over time, it can lead to loss of central vision, making it difficult to read, write, drive, or recognize others.
It’s this form of the disease that’s affected by the cell implant technique.
Symptoms of the “wet” form can be kept at bay with injections into the eye.
“Our study shows that this unique stem cell-based retinal implant thus far is well-tolerated, and preliminary results suggest it may help people with advanced dry age-related macular degeneration,” said Dr. Mark S. Humayun, a study co-author, lead inventor of the implant, and director of the USC Institute for Biomedical Therapeutics and co-director of the USC Roski Eye Institute.
Kashani is encouraged by early results.
“This treatment offers fantastic possibilities,” he said.
The results of the treatment
The treatment, which consists of a layer of human embryonic stem cell-derived RPE cells on an ultrathin supportive structure, was implanted in the retina of four patients by a USC Roski Eye Institute surgeon.
The work of a lot of people and institutions went into creating and testing this tiny implant.
Physicians and researchers at the USC Roski Eye Institute have collaborated with other California institutions.
The results of the first study, which was funded in part by the California Institute for Regenerative Medicines, was this month in Science Translational Medicine.
The trial lasted a year, during which the participants were followed to assess the implant’s safety.
The treatment appears to have been well-tolerated as there were no severe adverse events related to the implant or the surgical procedure.
There was also evidence that the implant integrated with the patients’ retinal tissue, which is essential for the treatment to be able to improve visual function.
The researchers discovered that their patients’ retinas displayed anatomical changes that were consistent with the reappearance of the RPE.
The study also sought to measure any visual improvement.
The research team’s preliminary assessment showed one person had improvement in visual acuity, which was measured by how many letters they could read on an eye chart.
As part of the study, the research team also performed a preliminary assessment of the therapy’s efficacy.
Two other patients had gains in visual function, which was measured by how well they could use the area of the retina treated by the implant.
None of the patients showed any additional vision loss.
A happy researcher
Among the people most excited by the preliminary results is one of the researchers who helped to develop the implant.
Dr. David R. Hinton is a professor of pathology at the Keck School of Medicine at USC.
Hinton was doing work with fruit flies when he was happily sidetracked into vision issues.
“For the vast majority [of people], there is no effective therapy,” he told Dr.China. “This study shows the potential is there.”
What began as a lab experiment has morphed over 11 years to a place where scientists are developing therapies.
“I never thought I’d see this in my career,” Hinton said.
Taking advantage of the fact that human stem cells can differentiate, the team developed “a good method with high purity,” Hinton said.
Knowing that a test — no matter how promising — with only four patients isn’t enough to offer as a treatment for a wide array of people, Hinton is looking toward the next stage: a larger clinical trial.
Since clinical trials are expensive, the group will have to write a grant and seek funding.
Nevertheless, “this is the most exciting thing [to have happened] in my academic career,” he said.
Their research may not lead to a cure, the researchers acknowledged. But they think it’s likely that additional trials and research will allow them — and others — to develop additional therapies that slow the progression of the disease.
Long enough for you to keep your vision for another 20 or 30 years.