Researchers Are Testing a New Stem Cell Therapy in the Hopes of Saving Millions from Blindness

Researchers Are Testing a New Stem Cell Therapy in the Hopes of Saving Millions from Blindness

NIH researchers in Kapil Bharti's lab work toward the development of induced pluripotent stem cells to treat dry age-related macular degeneration.

(Screenshot from video: rb.gy/oz2idg)



Of all the infirmities of old age, failing sight is among the cruelest. It can mean the end not only of independence, but of a whole spectrum of joys—from gazing at a sunset or a grandchild's face to reading a novel or watching TV.

The Phase 1 trial will likely run through 2022, followed by a larger Phase 2 trial that could last another two or three years.

The leading cause of vision loss in people over 55 is age-related macular degeneration, or AMD, which afflicts an estimated 11 million Americans. As photoreceptors in the macula (the central part of the retina) die off, patients experience increasingly severe blurring, dimming, distortions, and blank spots in one or both eyes.

The disorder comes in two varieties, "wet" and "dry," both driven by a complex interaction of genetic, environmental, and lifestyle factors. It begins when deposits of cellular debris accumulate beneath the retinal pigment epithelium (RPE)—a layer of cells that nourish and remove waste products from the photoreceptors above them. In wet AMD, this process triggers the growth of abnormal, leaky blood vessels that damage the photoreceptors. In dry AMD, which accounts for 80 to 90 percent of cases, RPE cells atrophy, causing photoreceptors to wither away. Wet AMD can be controlled in about a quarter of patients, usually by injections of medication into the eye. For dry AMD, no effective remedy exists.

Stem Cells: Promise and Perils

Over the past decade, stem cell therapy has been widely touted as a potential treatment for AMD. The idea is to augment a patient's ailing RPE cells with healthy ones grown in the lab. A few small clinical trials have shown promising results. In a study published in 2018, for example, a University of Southern California team cultivated RPE tissue from embryonic stem cells on a plastic matrix and transplanted it into the retinas of four patients with advanced dry AMD. Because the trial was designed to test safety rather than efficacy, lead researcher Amir Kashani told a reporter, "we didn't expect that replacing RPE cells would return a significant amount of vision." Yet acuity improved substantially in one recipient, and the others regained their lost ability to focus on an object.

Therapies based on embryonic stem cells, however, have two serious drawbacks: Using fetal cell lines raises ethical issues, and such treatments require the patient to take immunosuppressant drugs (which can cause health problems of their own) to prevent rejection. That's why some experts favor a different approach—one based on induced pluripotent stem cells (iPSCs). Such cells, first produced in 2006, are made by returning adult cells to an undifferentiated state, and then using chemicals to reprogram them as desired. Treatments grown from a patient's own tissues could sidestep both hurdles associated with embryonic cells.

At least hypothetically. Today, the only stem cell therapies approved by the U.S. Food and Drug Administration (FDA) are umbilical cord-derived products for various blood and immune disorders. Although scientists are probing the use of embryonic stem cells or iPSCs for conditions ranging from diabetes to Parkinson's disease, such applications remain experimental—or fraudulent, as a growing number of patients treated at unlicensed "stem cell clinics" have painfully learned. (Some have gone blind after receiving bogus AMD therapies at those facilities.)

Last December, researchers at the National Eye Institute in Bethesda, Maryland, began enrolling patients with dry AMD in the country's first clinical trial using tissue grown from the patients' own stem cells. Led by biologist Kapil Bharti, the team intends to implant custom-made RPE cells in 12 recipients. If the effort pans out, it could someday save the sight of countless oldsters.

That, however, is what's technically referred to as a very big "if."

The First Steps

Bharti's trial is not the first in the world to use patient-derived iPSCs to treat age-related macular degeneration. In 2013, Japanese researchers implanted such cells into the eyes of a 77-year-old woman with wet AMD; after a year, her vision had stabilized, and she no longer needed injections to keep abnormal blood vessels from forming. A second patient was scheduled for surgery—but the procedure was canceled after the lab-grown RPE cells showed signs of worrisome mutations. That incident illustrates one potential problem with using stem cells: Under some circumstances, the cells or the tissue they form could turn cancerous.

"The knowledge and expertise we're gaining can be applied to many other iPSC-based therapies."

Bharti and his colleagues have gone to great lengths to avoid such outcomes. "Our process is significantly different," he told me in a phone interview. His team begins with patients' blood stem cells, which appear to be more genomically stable than the skin cells that the Japanese group used. After converting the blood cells to RPE stem cells, his team cultures them in a single layer on a biodegradable scaffold, which helps them grow in an orderly manner. "We think this material gives us a big advantage," Bharti says. The team uses a machine-learning algorithm to identify optimal cell structure and ensure quality control.

It takes about six months for a patch of iPSCs to become viable RPE cells. When they're ready, a surgeon uses a specially-designed tool to insert the tiny structure into the retina. Within days, the scaffold melts away, enabling the transplanted RPE cells to integrate fully into their new environment. Bharti's team initially tested their method on rats and pigs with eye damage mimicking AMD. The study, published in January 2019 in Science Translational Medicine, found that at ten weeks, the implanted RPE cells continued to function normally and protected neighboring photoreceptors from further deterioration. No trace of mutagenesis appeared.

Encouraged by these results, Bharti began recruiting human subjects. The Phase 1 trial will likely run through 2022, followed by a larger Phase 2 trial that could last another two or three years. FDA approval would require an even larger Phase 3 trial, with a decision expected sometime between 2025 and 2028—that is, if nothing untoward happens before then. One unknown (among many) is whether implanted cells can thrive indefinitely under the biochemically hostile conditions of an eye with AMD.

"Most people don't have a sense of just how long it takes to get something like this to work, and how many failures—even disasters—there are along the way," says Marco Zarbin, professor and chair of Ophthalmology and visual science at Rutgers New Jersey Medical School and co-editor of the book Cell-Based Therapy for Degenerative Retinal Diseases. "The first kidney transplant was done in 1933. But the first successful kidney transplant was in 1954. That gives you a sense of the time frame. We're really taking the very first steps in this direction."

Looking Ahead

Even if Bharti's method proves safe and effective, there's the question of its practicality. "My sense is that using induced pluripotent stem cells to treat the patient from whom they're derived is a very expensive undertaking," Zarbin observes. "So you'd have to have a very dramatic clinical benefit to justify that cost."

Bharti concedes that the price of iPSC therapy is likely to be high, given that each "dose" is formulated for a single individual, requires months to manufacture, and must be administered via microsurgery. Still, he expects economies of scale and production to emerge with time. "We're working on automating several steps of the process," he explains. "When that kicks in, a technician will be able to make products for 10 or 20 people at once, so the cost will drop proportionately."

Meanwhile, other researchers are pressing ahead with therapies for AMD using embryonic stem cells, which could be mass-produced to treat any patient who needs them. But should that approach eventually win FDA approval, Bharti believes there will still be room for a technique that requires neither fetal cell lines nor immunosuppression.

And not only for eye ailments. "The knowledge and expertise we're gaining can be applied to many other iPSC-based therapies," says the scientist, who is currently consulting with several companies that are developing such treatments. "I'm hopeful that we can leverage these approaches for a wide range of applications, whether it's for vision or across the body."

NEI launches iPS cell therapy trial for dry AMD

Kenneth Miller
Kenneth Miller is a freelance writer based in Los Angeles. He is a contributing editor at Discover, and has reported from four continents for publications including Time, Life, Rolling Stone, Mother Jones, and Aeon. His honors include The ASJA Award for Best Science Writing and the June Roth Memorial Award for Medical Writing. Visit his website at www.kennethmiller.net.
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Artificial avatars for hire and sophisticated video manipulation carry profound implications for society.

Image by Rostyslav Savchyn on Unsplash

This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.

Alethea.ai sports a grid of faces smiling, blinking and looking about. Some are beautiful, some are oddly familiar, but all share one thing in common—they are fake.

Alethea creates "synthetic media"— including digital faces customers can license saying anything they choose with any voice they choose. Companies can hire these photorealistic avatars to appear in explainer videos, advertisements, multimedia projects or any other applications they might dream up without running auditions or paying talent agents or actor fees. Licenses begin at a mere $99. Companies may also license digital avatars of real celebrities or hire mashups created from real celebrities including "Don Exotic" (a mashup of Donald Trump and Joe Exotic) or "Baby Obama" (a large-eared toddler that looks remarkably similar to a former U.S. President).

Naturally, in the midst of the COVID pandemic, the appeal is understandable. Rather than flying to a remote location to film a beer commercial, an actor can simply license their avatar to do the work for them. The question is—where and when this tech will cross the line between legitimately licensed and authorized synthetic media to deep fakes—synthetic videos designed to deceive the public for financial and political gain.

Deep fakes are not new. From written quotes that are manipulated and taken out of context to audio quotes that are spliced together to mean something other than originally intended, misrepresentation has been around for centuries. What is new is the technology that allows this sort of seamless and sophisticated deception to be brought to the world of video.

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Jeanette DePatie describes herself as a professional “techsplainer”--taking complicated technologies and technological concepts and breaking them down into everyday language that everyone can understand. She has shared her entertaining and educational views on technology trends with companies like, McDonalds, Reynolds, Meredith, Better Homes and Gardens, Facebook and 20th Century Fox. She also proudly boasts that she once raised several million dollars in venture capital for a technology company with a presentation featuring two pieces of PVC pipe, a plastic funnel and a rubber chicken. She has been hired to describe technology by a host of Fortune 500 companies including Adobe, Apple, Intel, Microsoft, Monsanto, NTT Electronics, Panasonic, Pulitzer Samsung and Sony. She has spoken at CES, NAB, SMPTE CEATECH The Lean Startup Conference and a variety of Colleges and Universities.
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Morale at federal science agencies -- and public trust in their guidance -- is at a concerning low right now.

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This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.

It didn't have to be this way. More than 200,000 Americans dead, seven million infected, with numbers continuing to climb, an economy in shambles with millions out of work, hundreds of thousands of small businesses crushed with most of the country still under lockdown. And all with no end in sight. This catastrophic result is due in large part to the willful disregard of scientific evidence and of muzzling policy experts by the Trump White House, which has spent its entire time in office attacking science.

One of the few weapons we had to combat the spread of Covid-19—wearing face masks—has been politicized by the President, who transformed this simple public health precaution into a first amendment issue to rally his base. Dedicated public health officials like Dr. Anthony Fauci, the highly respected director of the National Institute of Allergies and Infectious Diseases, have received death threats, which have prompted many of them around the country to resign.

Over the summer, the Trump White House pressured the Centers for Disease Control, which is normally in charge of fighting epidemics, to downplay COVID risks among young people and encourage schools to reopen. And in late September, the CDC was forced to pull federal teams who were going door-to-door doing testing surveys in Minnesota because of multiple incidents of threats and abuse. This list goes on and on.

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Linda Marsa
Linda Marsa is a contributing editor at Discover, a former Los Angeles Times reporter and author of Fevered: Why a Hotter Planet Will Harm Our Health and How We Can Save Ourselves (Rodale, 2013), which the New York Times called “gripping to read.” Her work has been anthologized in The Best American Science Writing, and she has written for numerous publications, including Newsweek, U.S. News & World Report, Nautilus, Men’s Journal, Playboy, Pacific Standard and Aeon.