Researchers Are Testing a New Stem Cell Therapy in the Hopes of Saving Millions from Blindness
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
Meet the Psychologist Using Psychedelics to Treat Racial Trauma
Monnica Williams was stuck. The veteran psychologist wanted to conduct a study using psychedelics, but her university told her they didn't have the expertise to evaluate it via an institutional review board, which is responsible for providing ethical and regulatory oversight for research that involves human participants. Instead, they directed her to a hospital, whose reviewers turned it down, citing research of a banned substance as unethical.
"I said, 'We're not using illegal psilocybin, we're going through Health Canada,'" Williams said. Psilocybin was banned in Canada in 1974, but can now be obtained with an exemption from Health Canada, the federal government's health policy department. After learning this, the hospital review board told Williams they couldn't review her proposal because she's not affiliated with the hospital, after all.
It's all part of balancing bureaucracy with research goals for Williams, a leading expert on racial trauma and psychedelic medicine, as well as obsessive compulsive disorder (OCD), at the University of Ottawa. She's exploring the use of hallucinogenic substances like MDMA and psilocybin — commonly known as ecstasy and magic mushrooms, respectively — to help people of color address the psychological impacts of systemic racism. A prolific researcher, Williams also works as an expert witness, offering clinical evaluations for racial trauma cases.
Scientists have long known that psychedelics produce an altered state of consciousness and openness to new perspectives. For people with mental health conditions who haven't benefited from traditional therapy, psychedelics may be able to help them discover what's causing their pain or trauma, including racial trauma—the mental and emotional injury spurred by racial bias.
"Using psychedelics can not only bring these pain points to the surface for healing, but can reduce the anxiety or response to these memories and allow them to speak openly about them without the pain they bring," Williams says. Her research harnesses the potential of psychedelics to increase neuroplasticity, which includes the brain's ability to build new pathways.
"People of color are dealing with racism all the time, in large and small ways, and even dealing with racism in healthcare, even dealing with racism in therapy."
But she says therapists of color aren't automatically equipped to treat racial trauma. First, she notes, people of color are "vastly underrepresented in the mental health workforce." This is doubly true in psychedelic-assisted psychotherapy, in which a person is guided through a psychedelic session by a therapist or team of therapists, then processes the experience in subsequent therapy sessions.
"On top of that, the therapists of color are getting the same training that the white therapists are getting, so it's not even really guaranteed that they're going to be any better at helping a person that may have racial trauma emerging as part of their experience," she says.
In her own training to become a clinical psychologist at the University of Virginia, Williams says she was taught "how to be a great psychologist for white people." Yet even people of color, she argues, need specialized training to work with marginalized groups, particularly when it comes to MDMA, psilocybin and other psychedelics. Because these drugs can lower natural psychological defense mechanisms, Williams says, it's important for providers to be specially trained.
"People of color are dealing with racism all the time, in large and small ways, and even dealing with racism in healthcare, even dealing with racism in therapy. So [they] generally develop a lot of defenses and coping strategies to ward off racism so that they can function." she says. This is particularly true with psychedelic-assisted psychotherapy: "One possibility is that you're going to be stripped of your defenses, you're going to be vulnerable. And so you have to work with a therapist who is going to understand that and not enact more racism in their work with you."
Williams has struggled to find funding and institutional approval for research involving psychedelics, or funding for investigations into racial trauma or the impacts of conditions like OCD and post-traumatic stress disorder (PTSD) in people of color. With the bulk of her work focusing on OCD, she hoped to focus on people of color, but found there was little funding for that type of research. In 2020, that started to change as structural racism garnered more media attention.
After the killing of George Floyd, a 46-year-old Black man, by a white police officer in May 2020, Williams was flooded with media requests. "Usually, when something like that happens, I get contacted a lot for a couple of weeks, and it dies off. But after George Floyd, it just never did."
Monnica Williams, clinical psychologist at the University of Ottawa
Williams was no stranger to the questions that soon blazed across headlines: How can we mitigate microaggressions? How do race and ethnicity impact mental health? What terms should we use to discuss racial issues? What constitutes an ally, and why aren't there more of them? Why aren't there more people of color in academia, and so many other fields?
Now, she's hoping that the increased attention on racial justice will mean more acceptance for the kind of research she's doing.
In fact, Williams herself has used psychedelics in order to gain a better understanding of how to use them to treat racial trauma. In a study published in January, she and two other Black female psychotherapists took MDMA in a supervised setting, guided by a team of mental health practitioners who helped them process issues that came up as the session progressed. Williams, who was also the study's lead author, found that participants' experiences centered around processing and finding release from racial identities, and, in one case, of simply feeling wholly human without the burden of racial identity for the first time.
The purpose of the study was twofold: to understand how Black women react to psychedelics and to provide safe, firsthand, psychedelic experiences to Black mental health practitioners. One of the other study participants has since gone on to offer psychedelic-assisted psychotherapy to her own patients.
Psychedelic research, and psilocybin in particular, has become a hot topic of late, particularly after Oregon became the first state to legalize it for therapeutic use last November. A survey-based, observational study with 313 participants, published in 2020, paved the way for Williams' more recent MDMA experiments by describing improvements in depression, anxiety and racial trauma among people of color who had used LSD, psilocybin or MDMA in a non-research setting.
Williams and her team included only respondents who reported a moderate to strong psychoactive effect of past psychedelic consumption and believed these experiences provided "relief from the challenging effects of ethnic discrimination." Participants reported a memorable psychedelic experience as well as its acute and lasting effects, completing assessments of psychological insight, mystical experience and emotional challenges experienced during psychedelic experience, then describing their mental health — including depression, anxiety and trauma symptoms — before and after that experience.
Still, Williams says addressing racism is much more complex than treating racial trauma. "One of the questions I get asked a lot is, 'How can Black people cope with racism?' And I don't really like that question," she says. "I think it's important and I don't mind answering it, but I think the more important question is, how can we end racism? What can Black people do to stop racism that's happening to them and what can we do as a society to stop racism? And people aren't really asking this question."
Tiny, Injectable Robots Could Be the Future of Brain Treatments
In the 1966 movie "Fantastic Voyage," actress Raquel Welch and her submarine were shrunk to the size of a cell in order to eliminate a blood clot in a scientist's brain. Now, 55 years later, the scenario is becoming closer to reality.
California-based startup Bionaut Labs has developed a nanobot about the size of a grain of rice that's designed to transport medication to the exact location in the body where it's needed. If you think about it, the conventional way to deliver medicine makes little sense: A painkiller affects the entire body instead of just the arm that's hurting, and chemotherapy is flushed through all the veins instead of precisely targeting the tumor.
"Chemotherapy is delivered systemically," Bionaut-founder and CEO Michael Shpigelmacher says. "Often only a small percentage arrives at the location where it is actually needed."
But what if it was possible to send a tiny robot through the body to attack a tumor or deliver a drug at exactly the right location?
Several startups and academic institutes worldwide are working to develop such a solution but Bionaut Labs seems the furthest along in advancing its invention. "You can think of the Bionaut as a tiny screw that moves through the veins as if steered by an invisible screwdriver until it arrives at the tumor," Shpigelmacher explains. Via Zoom, he shares the screen of an X-ray machine in his Culver City lab to demonstrate how the half-transparent, yellowish device winds its way along the spine in the body. The nanobot contains a tiny but powerful magnet. The "invisible screwdriver" is an external magnetic field that rotates that magnet inside the device and gets it to move and change directions.
The current model has a diameter of less than a millimeter. Shpigelmacher's engineers could build the miniature vehicle even smaller but the current size has the advantage of being big enough to see with bare eyes. It can also deliver more medicine than a tinier version. In the Zoom demonstration, the micorobot is injected into the spine, not unlike an epidural, and pulled along the spine through an outside magnet until the Bionaut reaches the brainstem. Depending which organ it needs to reach, it could be inserted elsewhere, for instance through a catheter.
"The hope is that we can develop a vehicle to transport medication deep into the body."
Imagine moving a screw through a steak with a magnet — that's essentially how the device works. But of course, the Bionaut is considerably different from an ordinary screw: "At the right location, we give a magnetic signal, and it unloads its medicine package," Shpigelmacher says.
To start, Bionaut Labs wants to use its device to treat Parkinson's disease and brain stem gliomas, a type of cancer that largely affects children and teenagers. About 300 to 400 young people a year are diagnosed with this type of tumor. Radiation and brain surgery risk damaging sensitive brain tissue, and chemotherapy often doesn't work. Most children with these tumors live less than 18 months. A nanobot delivering targeted chemotherapy could be a gamechanger. "These patients really don't have any other hope," Shpigelmacher says.
Of course, the main challenge of the developing such a device is guaranteeing that it's safe. Because tissue is so sensitive, any mistake could risk disastrous results. Over the past four years, Bionaut has tested its technology in dozens of healthy sheep and pigs with no major adverse effects. Sheep make a good stand-in for humans because their brains and spines are similar to ours.
The Bionaut device is about the size of a grain of rice.
Bionaut Labs
"As the Bionaut moves through brain tissue, it creates a transient track that heals within a few weeks," Shpigelmacher says. The company is hoping to be the first to test a nanobot in humans. That could happen as early as 2023, Shpigelmacher says.
Once the technique has been perfected, further applications could include addressing other kinds of brain disorders that are considered incurable now, such as Alzheimer's or Huntington's disease. "Microrobots could serve as a bridgehead, opening the gateway to the brain and facilitating precise access of deep brain structure – either to deliver medication, take cell samples or stimulate specific brain regions," Shpigelmacher says.
Robot-assisted hybrid surgery with artificial intelligence is already used in state-of-the-art surgery centers, and many medical experts believe that nanorobotics will be the instrument of the future. In 2016, three scientists were awarded the Nobel Prize in Chemistry for their development of "the world's smallest machines," nano "elevators" and minuscule motors. Since then, the scientific experiments have progressed to the point where applicable devices are moving closer to actually being implemented.
Bionaut's technology was initially developed by a research team lead by Peer Fischer, head of the independent Micro Nano and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany. Fischer is considered a pioneer in the research of nano systems, which he began at Harvard University more than a decade ago. He and his team are advising Bionaut Labs and have licensed their technology to the company.
"The hope is that we can develop a vehicle to transport medication deep into the body," says Max Planck scientist Tian Qiu, who leads the cooperation with Bionaut Labs. He agrees with Shpigelmacher that the Bionaut's size is perfect for transporting medication loads and is researching potential applications for even smaller nanorobots, especially in the eye, where the tissue is extremely sensitive. "Nanorobots can sneak through very fine tissue without causing damage."
In "Fantastic Voyage," Raquel Welch's adventures inside the body of a dissident scientist let her swim through his veins into his brain, but her shrunken miniature submarine is attacked by antibodies; she has to flee through the nerves into the scientist's eye where she escapes into freedom on a tear drop. In reality, the exit in the lab is much more mundane. The Bionaut simply leaves the body through the same port where it entered. But apart from the dramatization, the "Fantastic Voyage" was almost prophetic, or, as Shpigelmacher says, "Science fiction becomes science reality."