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.
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
New Blood Test Can Detect Lymphoma Cells Before a Tumor Grows Back
David Kurtz making DNA sequencing libraries in his lab.
When David M. Kurtz was doing his clinical fellowship at Stanford University Medical Center in 2009, specializing in lymphoma treatments, he found himself grappling with a question no one could answer. A typical regimen for these blood cancers prescribed six cycles of chemotherapy, but no one knew why. "The number seemed to be drawn out of a hat," Kurtz says. Some patients felt much better after just two doses, but had to endure the toxic effects of the entire course. For some elderly patients, the side effects of chemo are so harsh, they alone can kill. Others appeared to be cancer-free on the CT scans after the requisite six but then succumbed to it months later.
"Anecdotally, one patient decided to stop therapy after one dose because he felt it was so toxic that he opted for hospice instead," says Kurtz, now an oncologist at the center. "Five years down the road, he was alive and well. For him, just one dose was enough." Others would return for their one-year check up and find that their tumors grew back. Kurtz felt that while CT scans and MRIs were powerful tools, they weren't perfect ones. They couldn't tell him if there were any cancer cells left, stealthily waiting to germinate again. The scans only showed the tumor once it was back.
Blood cancers claim about 68,000 people a year, with a new diagnosis made about every three minutes, according to the Leukemia Research Foundation. For patients with B-cell lymphoma, which Kurtz focuses on, the survival chances are better than for some others. About 60 percent are cured, but the remaining 40 percent will relapse—possibly because they will have a negative CT scan, but still harbor malignant cells. "You can't see this on imaging," says Michael Green, who also treats blood cancers at University of Texas MD Anderson Medical Center.
The new blood test is sensitive enough to spot one cancerous perpetrator amongst one million other DNA molecules.
Kurtz wanted a better diagnostic tool, so he started working on a blood test that could capture the circulating tumor DNA or ctDNA. For that, he needed to identify the specific mutations typical for B-cell lymphomas. Working together with another fellow PhD student Jake Chabon, Kurtz finally zeroed-in on the tumor's genetic "appearance" in 2017—a pair of specific mutations sitting in close proximity to each other—a rare and telling sign. The human genome contains about 3 billion base pairs of nucleotides—molecules that compose genes—and in case of the B-cell lymphoma cells these two mutations were only a few base pairs apart. "That was the moment when the light bulb went on," Kurtz says.
The duo formed a company named Foresight Diagnostics, focusing on taking the blood test to the clinic. But knowing the tumor's mutational signature was only half the process. The other was fishing the tumor's DNA out of patients' bloodstream that contains millions of other DNA molecules, explains Chabon, now Foresight's CEO. It would be like looking for an escaped criminal in a large crowd. Kurtz and Chabon solved the problem by taking the tumor's "mug shot" first. Doctors would take the biopsy pre-treatment and sequence the tumor, as if taking the criminal's photo. After treatments, they would match the "mug shot" to all DNA molecules derived from the patient's blood sample to see if any molecular criminals managed to escape the chemo.
Foresight isn't the only company working on blood-based tumor detection tests, which are dubbed liquid biopsies—other companies such as Natera or ArcherDx developed their own. But in a recent study, the Foresight team showed that their method is significantly more sensitive in "fishing out" the cancer molecules than existing tests. Chabon says that this test can detect circulating tumor DNA in concentrations that are nearly 100 times lower than other methods. Put another way, it's sensitive enough to spot one cancerous perpetrator amongst one million other DNA molecules.
"It increases the sensitivity of detection and really catches most patients who are going to progress," says Green, the University of Texas oncologist who wasn't involved in the study, but is familiar with the method. It would also allow monitoring patients during treatment and making better-informed decisions about which therapy regimens would be most effective. "It's a minimally invasive test," Green says, and "it gives you a very high confidence about what's going on."
Having shown that the test works well, Kurtz and Chabon are planning a new trial in which oncologists would rely on their method to decide when to stop or continue chemo. They also aim to extend their test to detect other malignancies such as lung, breast or colorectal cancers. The latest genome sequencing technologies have sequenced and catalogued over 2,500 different tumor specimens and the Foresight team is analyzing this data, says Chabon, which gives the team the opportunity to create more molecular "mug shots."
The team hopes that that their blood cancer test will become available to patients within about five years, making doctors' job easier, and not only at the biological level. "When I tell patients, "good news, your cancer is in remission', they ask me, 'does it mean I'm cured?'" Kurtz says. "Right now I can't answer this question because I don't know—but I would like to." His company's test, he hopes, will enable him to reply with certainty. He'd very much like to have the power of that foresight.
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
The First Mass-Produced Solar Car Is Coming Soon, Sparking Excitement and Uncertainty
Reporter Michaela Haas takes Aptera's Sol car out for a test drive in San Diego, Calif.
The white two-seater car that rolls down the street in the Sorrento Valley of San Diego looks like a futuristic batmobile, with its long aerodynamic tail and curved underbelly. Called 'Sol' (Spanish for "sun"), it runs solely on solar and could be the future of green cars. Its maker, the California startup Aptera, has announced the production of Sol, the world's first mass-produced solar vehicle, by the end of this year. Aptera co-founder Chris Anthony points to the sky as he says, "On this sunny California day, there is ample fuel. You never need to charge the car."
If you live in a sunny state like California or Florida, you might never need to plug in the streamlined Sol because the solar panels recharge while driving and parked. Its 60-mile range is more than the average commuter needs. For cloudy weather, battery packs can be recharged electronically for a range of up to 1,000 miles. The ultra-aerodynamic shape made of lightweight materials such as carbon, Kevlar, and hemp makes the Sol four times more energy-efficient than a Tesla, according to Aptera. "The material is seven times stronger than steel and even survives hail or an angry ex-girlfriend," Anthony promises.
Co-founder Steve Fambro opens the Sol's white doors that fly upwards like wings and I get inside for a test drive. Two dozen square solar panels, each the size of a large square coaster, on the roof, front, and tail power the car. The white interior is spartan; monitors have replaced mirrors and the dashboard. An engineer sits in the driver's seat, hits the pedal, and the low-drag two-seater zooms from 0 to 60 in 3.5 seconds.
It feels like sitting in a race car because the two-seater is so low to the ground but the car is built to go no faster than 100 or 110 mph. The finished car will weigh less than 1,800 pounds, about half of the smallest Tesla. The average car, by comparison, weighs more than double that. "We've built it primarily for energy efficiency," Steve Fambro says, explaining why the Sol has only three wheels. It's technically an "auto-cycle," a hybrid between a motorcycle and a car, but Aptera's designers are also working to design a four-seater.
There has never been a lack of grand visions for the future of the automobile, but until these solar cars actually hit the streets, nobody knows how the promises will hold up.
Transportation is currently the biggest source of greenhouse gases. Developing an efficient solar car that does not burden the grid has been the dream of innovators for decades. Every other year, dozens of innovators race their self-built solar cars 2,000 miles through the Australian desert.
More effective solar panels are finally making the dream mass-compatible, but just like other innovative car ideas, Aptera's vision has been plagued with money problems. Anthony and Fambro were part of the original crew that founded Aptera in 2006 and worked on the first prototype around the same time Tesla built its first roadster, but Aptera went bankrupt in 2011. Anthony and Fambro left a year before the bankruptcy and went on to start other companies. Among other projects, Fambro developed the first USDA organic vertical farm in the United Arab Emirates, and Anthony built a lithium battery company, before the two decided to buy Aptera back. Without a billionaire such as Elon Musk bankrolling the risky process of establishing a whole new car production system from scratch, the huge production costs are almost insurmountable.
But Aptera's founders believe they have found solutions for the entire production process as well as the car design. Most parts of the Sol's body can be made by 3D printers and assembled like a Lego kit. If this makes you think of a toy car, Anthony assures potential buyers that the car aced stress tests and claims it's safer than any vehicle on the market, "because the interior is shaped like an egg and if there is an impact, the pressure gets distributed equally." However, Aptera has yet to release crash test safety data so outside experts cannot evaluate their claims.
Instead of building a huge production facility, Anthony and Fambro envision "micro-factories," each less than 10,000 square feet, where a small crew can assemble cars on demand wherever the orders are highest, be it in California, Canada, or China.
If a part of the Sol breaks, Aptera promises to send replacement parts to any corner of the world within 24 hours, with instructions. So a mechanic in a rural corner in Arkansas or China who never worked on a solar car before simply needs to download the instructions and replace the broken part. At least that's the idea. "The material does not rust nor fatigue," Fambro promises. "You can pass the car onto your grandchildren. When more efficient solar panels hit the market, we simply replace them."
More than 11,000 potential buyers have already signed up; the cheapest model costs around $26,000 USD and Aptera expects the first cars to ship by the end of the year.
Two other solar carmakers are vying for the pole position in the race to be the first to market: The German startup Sono has also announced it will also produce its first solar car by the end of this year. The price tag for the basic model is also around $26,000, but its concept is very different. From the outside, the Sion looks like a conservative minivan for a family; only a closer look reveals that the dark exterior is made of solar panels. Sono, too, nearly went bankrupt a few years ago and was saved through a crowdfunding campaign by enthusiastic fans.
Meanwhile, Norwegian company Lightyear wants to produce a sleek solar-powered luxury sedan by the end of the year, but its price of around $180,000 makes it unaffordable for most buyers.
There has never been a lack of grand visions for the future of the automobile, but until these solar cars actually hit the streets, nobody knows how the promises will hold up. How often will the cars need to be repaired? What happens when snow and ice cover the solar panels? Also, you can't park the car in a garage if you need the sun to charge it.
Critics, including students at the Solar Car team at the University of Michigan, say that mounting solar panels on a moving vehicle will never yield the most efficient results compared to static panels. Also, they are quick to point out that no company has managed to overcome the production hurdles yet. Others in the field also wonder how well the solar panels will actually work.
"It's important to realize that the solar mileage claims by these companies are likely the theoretical best case scenario but in the real world, solar range will be significantly less when you factor in shading, parking in garages, and geographies with lower solar irradiance," says Evan Stumpges, the team coordinator for the American Solar Challenge, a competition in which enthusiasts build and race solar-powered cars. "The encouraging thing is that I have seen videos of real working prototypes for each of these vehicles which is a key accomplishment. That said, I believe the biggest hurdle these companies have yet to face is successfully ramping up to volume production and understanding what their profitability point will be for selling the vehicles once production has stabilized."
Professor Daniel M. Kammen, the founding director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley, and one of the world's foremost experts on renewable energy, believes that the technical challenges have been solved, and that solar cars have real advantages over electric vehicles.
"This is the right time to be bullish. Cutting out the charging is a natural solution for long rides," he says. "These vehicles are essentially solar panels and batteries on wheels. These are now record low-cost and can be built from sustainable materials." Apart from Aptera's no-charge technology, he appreciates the move toward no-conflict materials. "Not only is the time ripe but the youth movement is pushing toward conflict-free material and reducing resource waste....A low-cost solar fleet could be really interesting in relieving burden on the grid, or you could easily imagine a city buying a bunch of them and connecting them with mass transit." While he has followed all three new solar companies with interest, he has already ordered an Aptera car for himself, "because it's American and it looks the most different."
After taking a spin in the Sol, it is startling to switch back into a regular four-seater. Rolling out of Aptera's parking lot onto the freeway next to all the oversized gas guzzlers that need to stop every couple of hundreds of miles to fill up, one can't help but think: We've just taken a trip into the future.