Ordinary people are living better with chronic conditions thanks to a recent explosion of developments in medical implants.
Beware, cyborgs walk among us. They’re mostly indistinguishable from regular humans and are infiltrating every nook and cranny of society. For full disclosure, I’m one myself. No, we’re not deadly intergalactic conquerors like the Borg race of Star Trek fame, just ordinary people living better with chronic conditions thanks to medical implants.
In recent years there has been an explosion of developments in implantable devices that merge multiple technologies into gadgets that work in concert with human physiology for the treatment of serious diseases. Pacemakers for the heart are the best-known implants, as well as other cardiac devices like LVADs (left-ventricular assist devices) and implanted defibrillators. Next-generation devices address an array of organ failures, and many are intended as permanent. The driving need behind this technology: a critical, persistent shortage of implantable biological organs.
The demand for transplantable organs dwarfs their availability. There are currently over 100,000 people on the transplant waiting list in the U.S., compared to 40,000 transplants completed in 2021. But even this doesn’t reflect the number of people in dire straits who don’t qualify for a transplant because of things like frailty, smoking status and their low odds of surviving the surgery.
My journey to becoming a cyborg came about because of a lifelong medical condition characterized by pathologically low motility of the digestive system, called gastroparesis. Ever since I was in my teens, I’ve had chronic problems with severe nausea. Flareups can be totally incapacitating and last anywhere from hours to months, interspersed with periods of relief. The cycle is totally unpredictable, and for decades my condition went both un- and misdiagnosed by doctors who were not even aware that the condition existed. Over the years I was labeled with whatever fashionable but totally inappropriate medical label existed at the time, and not infrequently, hypochondria.
Living with the gastric pacer is easy. In fact, most of the time, I don’t even know it’s there.
One of the biggest turning points in my life came when a surgeon at the George Washington University Hospital, Dr. Frederick Brody, ordered a gastric emptying test that revealed gastroparesis. This was in 2009, and an implantable device, called a gastric pacer, had been approved by the FDA for compassionate use, meaning that no other treatments were available. The small device is like a pacemaker that’s implanted beneath the skin of the abdomen and is attached to the stomach through electrodes that carry electrical pulses that stimulate the stomach, making it contract as it’s supposed to.
Dr. Brody implanted the electrical wires and the device, and, once my stomach started to respond to the pulses, I got the most significant nausea relief I’d had in decades of futile treatments. It sounds cliché to say that my debt to Dr. Brody is immeasurable, but the pacer has given me more years of relative normalcy than I previously could have dreamed of.
I should emphasize that the pacer is not a cure. I still take a lot of medicine and have to maintain a soft, primarily vegetarian diet, and the condition has progressed with age. I have ups and downs, and can still have periods of severe illness, but there’s no doubt I would be far worse off without the electrical stimulation provided by the pacer.
Living with the gastric pacer is easy. In fact, most of the time, I don’t even know it’s there. It entails periodic visits with a surgeon who can adjust the strength of the electrical pulses using a wireless device, so when symptoms are worse, he or she can amp up the juice. If the pulses are too strong, they can cause annoying contractions in the abdominal muscles, but this is easily fixed with a simple wireless adjustment. The battery runs down after a few years, and when this happens the whole device has to be replaced in what is considered minor surgery.
Such devices could fill gaps in treating other organ failures. By far most of the people on transplant waiting lists are waiting for kidneys. Despite the fact that live donations are possible, there’s still a dire shortage of organs. A bright spot on the horizon is The Kidney Project, a program spearheaded by bioengineer Shuvo Roy at the University of California, San Francisco, which is developing a fully implantable artificial kidney. The device combines living cells with artificial materials and relies not on a battery, but on the patient’s own blood pressure to keep it functioning.
Several years into this project, a prototype of the kidney, about the size of a smart phone, has been successfully tested in pigs. The device seems to provide many of the functions of a biological kidney (unlike dialysis, which replaces only one main function) and reliably produces urine. One of its most critical components is a special artificial membrane, called a hemofilter, that filters out toxins and waste products from the blood without leaking important molecules like albumin. Since it allows for total mobility, the artificial kidney will provide patients with a higher quality of life than those on dialysis, and is in some important ways, even better than a biological transplant.
The beauty of the device is that, even though it contains kidney cells sourced, as of now, from cadavers or pigs, the cells are treated so that they can’t be rejected and the device doesn’t require the highly problematic immunosuppressant drugs a biological organ requires. “Anti-rejection drugs,” says Roy, “make you susceptible to all kinds of infections and damage the transplanted organ, causing steady deterioration. Eventually they kill the kidney. A biological transplant has about a 10-year limit,” after which the kidney fails and the body rejects it.
Eventually, says Roy, the cells used in the artificial kidney will be sourced from the patient himself, the ultimate genetic match. The patient’s adult stem cells can be used to produce some or all of the 25 to 30 specialized cells of a biological kidney that provide all the functions of a natural organ. People formerly on dialysis could drastically improve their functionality and quality of life without being tethered to a machine for hours at a time, three days a week.
As exciting as this project is, it suffers from a common theme in early biomedical research—keeping a steady stream of funding that will move the project from the lab, into human clinical trials and eventually to the bedside. “It’s the issue,” says Roy. “Potential investors want to see more data indicating that it works, but you need funding to create data. It’s a Catch-22 that puts you in a kind of no-man’s land of funding.” The constant pursuit of funding introduces a variable that makes it hard to predict when the kidney will make it to market, despite the enormous need for such a technology.
Another critical variable is if and when insurance companies will decide to cover transplants with the artificial kidney, so that it becomes affordable for the average person. But Roy thinks that this hurdle, too, will be crossed. Insurance companies stand to save a great deal of money compared to what they ordinarily spend on transplant patients. The cost of yearly maintenance will be a fraction of that associated with the tens of thousands of dollars for immunosuppressant drugs and the attendant complications associated with a biological transplant.
One estimate that the multidisciplinary team of researchers involved with The Kidney Project are still trying to establish is how long the artificial kidney will last once transplanted into the body. Animal trials so far have been looking at how the kidney works for 30 days, and will soon extend that study to 90 days. Additional studies will extend much farther into the future, but first the kidneys have to be implanted into people who can be followed over many years to answer this question. But unlike the gastric pacer and other implants, there won’t be a need for periodic surgeries to replace a depleted battery, and the stark improvements in quality of life compared to dialysis add a special dimension to the value of whatever time the kidney lasts.
Another life-saving implant could address a major scourge of the modern world—heart disease. Despite significant advances in recent decades, including the cardiac implants mentioned above, cardiovascular disease still causes one in three deaths across the world. One of the most promising developments in recent years is the Total Artificial Heart, a pneumatically driven device that can be used in patients with biventricular heart failure, affecting both sides of the heart, when a biological organ is not available.
The TAH is implanted in the chest cavity and has two tubes that snake down the body, come out through the abdomen and attach to a 13.5-pound external driver that the patient carries around in a backpack. It was first developed as a bridge to transplant, a temporary alternative while the patient waited for a biological heart to replace it. However, SynCardia Systems, LLC, the Tucson-based company that makes it, is now investigating whether the heart can be used on a long-term basis.
There’s good reason to think that this will be the case. I spoke with Daniel Teo, one of the board members of SynCardia, who said that so far, one patient lived with the TAH for six years and nine months, before he died of other causes. Another patient, still alive, has lived with the device for over five years and another one has lived with it for over four years. About 2,000 of these transplants have been done in patients waiting for biological hearts so far, and most have lived mobile, even active lives. One TAH recipient hiked for 600 miles, and another ran the 4.2-mile Pat Tillman Run, both while on the artificial heart. This is a far cry from their activities before surgery, while living with advanced heart failure.
Randy Shepard, a recipient of the Total Artificial Heart, teaches archery to his son.
Randy Shepard
If removing and replacing one’s biological heart with a synthetic device sounds scary, it is. But then so is replacing one’s heart with biological one. “The TAH is very emotionally loaded for most people,” says Teo. “People sometimes hold back because of philosophical, existential questions and other nonmedical reasons.” He also cites cultural reasons why some people could be hesitant to accept an artificial heart, saying that some religions could frown upon it, just as they forbid other medical interventions.
The first TAHs that were approved were 70 cubic centimeters in size and fit into the chest cavities of men and larger women, but there’s now a smaller, 50 cc size meant for women and adolescents. The FDA first cleared the 70 cc heart as a bridge to transplant in 2004, and the 50 cc model received approval in 2014. SynCardia’s focus now is on seeking FDA approval to use the heart on a long-term basis. There are other improvements in the works.
One issue being refined deals with the external driver that holds the pneumatic device for moving the blood through a patient’s body. The two tubes connecting the driver to the heart entail openings in the skin that could get infected, and carrying the backpack is less than ideal. The driver also makes an audible sound that some people find disturbing. The next generation TAH will be quieter and involve wearing a smaller, lighter device on a belt rather than carrying the backpack. SynCardia is also working toward a fully implantable heart that wouldn’t require any external components and would contain an energy source that can be recharged wirelessly.
Teo says the jury is out as to whether artificial hearts will ever obviate the need for biological organs, but the world’s number one killer isn’t going away any time soon. “The heart is one of the strongest organs,” he says, “but it’s not made to last forever. If you live long enough, the heart will eventually fail, and heart failure leads to the failure of other organs like the kidney, the lungs and the liver.” As long as this remains the case and as long as the current direction of research continues, artificial organs are likely to play an ever larger part of our everyday lives.
Oh, wait. Maybe we cyborgs will take over the world after all.
In a recent research trial, patients with Parkinson's disease reported that their symptoms had improved after stem cells were implanted into their brains. Martin Taylor, far right, was diagnosed at age 32.
For years, there's been little improvement in the standard treatment. Patients are typically given the drug levodopa, a chemical that's absorbed by the brain’s nerve cells, or neurons, and converted into dopamine. This drug addresses the symptoms but has no impact on the course of the disease as patients continue to lose dopamine producing neurons. Eventually, the treatment stops working effectively.
BlueRock Therapeutics, a cell therapy company based in Massachusetts, is taking a different approach by focusing on the use of stem cells, which can divide into and generate new specialized cells. The company makes the dopamine-producing cells that patients have lost and inserts these cells into patients' brains. “We have a disease with a high unmet need,” says Ahmed Enayetallah, the senior vice president and head of development at BlueRock. “We know [which] cells…are lost to the disease, and we can make them. So it really came together to use stem cells in Parkinson's.”
In a phase 1 research trial announced late last month, patients reported that their symptoms had improved after a year of treatment. Brain scans also showed an increased number of neurons generating dopamine in patients’ brains.
Increases in dopamine signals
The recent phase 1 trial focused on deploying BlueRock’s cell therapy, called bemdaneprocel, to treat 12 patients suffering from Parkinson’s. The team developed the new nerve cells and implanted them into specific locations on each side of the patient's brain through two small holes in the skull made by a neurosurgeon. “We implant cells into the places in the brain where we think they have the potential to reform the neural networks that are lost to Parkinson's disease,” Enayetallah says. The goal is to restore motor function to patients over the long-term.
Five patients were given a relatively low dose of cells while seven got higher doses. Specialized brain scans showed evidence that the transplanted cells had survived, increasing the overall number of dopamine producing cells. The team compared the baseline number of these cells before surgery to the levels one year later. “The scans tell us there is evidence of increased dopamine signals in the part of the brain affected by Parkinson's,” Enayetallah says. “Normally you’d expect the signal to go down in untreated Parkinson’s patients.”
"I think it has a real chance to reverse motor symptoms, essentially replacing a missing part," says Tilo Kunath, a professor of regenerative neurobiology at the University of Edinburgh.
The team also asked patients to use a specific type of home diary to log the times when symptoms were well controlled and when they prevented normal activity. After a year of treatment, patients taking the higher dose reported symptoms were under control for an average of 2.16 hours per day above their baselines. At the smaller dose, these improvements were significantly lower, 0.72 hours per day. The higher-dose patients reported a corresponding decrease in the amount of time when symptoms were uncontrolled, by an average of 1.91 hours, compared to 0.75 hours for the lower dose. The trial was safe, and patients tolerated the year of immunosuppression needed to make sure their bodies could handle the foreign cells.
Claire Bale, the associate director of research at Parkinson's U.K., sees the promise of BlueRock's approach, while noting the need for more research on a possible placebo effect. The trial participants knew they were getting the active treatment, and placebo effects are known to be a potential factor in Parkinson’s research. Even so, “The results indicate that this therapy produces improvements in symptoms for Parkinson's, which is very encouraging,” Bale says.
Tilo Kunath, a professor of regenerative neurobiology at the University of Edinburgh, also finds the results intriguing. “I think it's excellent,” he says. “I think it has a real chance to reverse motor symptoms, essentially replacing a missing part.” However, it could take time for this therapy to become widely available, Kunath says, and patients in the late stages of the disease may not benefit as much. “Data from cell transplantation with fetal tissue in the 1980s and 90s show that cells did not survive well and release dopamine in these [late-stage] patients.”
Searching for the right approach
There's a long history of using cell therapy as a treatment for Parkinson's. About four decades ago, scientists at the University of Lund in Sweden developed a method in which they transferred parts of fetal brain tissue to patients with Parkinson's so that their nerve cells would produce dopamine. Many benefited, and some were able to stop their medication. However, the use of fetal tissue was highly controversial at that time, and the tissues were difficult to obtain. Later trials in the U.S. showed that people benefited only if a significant amount of the tissue was used, and several patients experienced side effects. Eventually, the work lost momentum.
“Like many in the community, I'm aware of the long history of cell therapy,” says Taylor, the patient living with Parkinson's. “They've long had that cure over the horizon.”
In 2000, Lorenz Studer led a team at the Memorial Sloan Kettering Centre, in New York, to find the chemical signals needed to get stem cells to differentiate into cells that release dopamine. Back then, the team managed to make cells that produced some dopamine, but they led to only limited improvements in animals. About a decade later, in 2011, Studer and his team found the specific signals needed to guide embryonic cells to become the right kind of dopamine producing cells. Their experiments in mice, rats and monkeys showed that their implanted cells had a significant impact, restoring lost movement.
Studer then co-founded BlueRock Therapeutics in 2016. Forming the most effective stem cells has been one of the biggest challenges, says Enayetallah, the BlueRock VP. “It's taken a lot of effort and investment to manufacture and make the cells at the right scale under the right conditions.” The team is now using cells that were first isolated in 1998 at the University of Wisconsin, a major advantage because they’re available in a virtually unlimited supply.
Other efforts underway
In the past several years, University of Lund researchers have begun to collaborate with the University of Cambridge on a project to use embryonic stem cells, similar to BlueRock’s approach. They began clinical trials this year.
A company in Japan called Sumitomo is using a different strategy; instead of stem cells from embryos, they’re reprogramming adults' blood or skin cells into induced pluripotent stem cells - meaning they can turn into any cell type - and then directing them into dopamine producing neurons. Although Sumitomo started clinical trials earlier than BlueRock, they haven’t yet revealed any results.
“It's a rapidly evolving field,” says Emma Lane, a pharmacologist at the University of Cardiff who researches clinical interventions for Parkinson’s. “But BlueRock’s trial is the first full phase 1 trial to report such positive findings with stem cell based therapies.” The company’s upcoming phase 2 research will be critical to show how effectively the therapy can improve disease symptoms, she added.
The cure over the horizon
BlueRock will continue to look at data from patients in the phase 1 trial to monitor the treatment’s effects over a two-year period. Meanwhile, the team is planning the phase 2 trial with more participants, including a placebo group.
For patients with Parkinson’s like Martin Taylor, the therapy offers some hope, though Taylor recognizes that more research is needed.
BlueRock Therapeutics
“Like many in the community, I'm aware of the long history of cell therapy,” he says. “They've long had that cure over the horizon.” His expectations are somewhat guarded, he says, but, “it's certainly positive to see…movement in the field again.”
"If we can demonstrate what we’re seeing today in a more robust study, that would be great,” Enayetallah says. “At the end of the day, we want to address that unmet need in a field that's been waiting for a long time.”
Editor's note: The company featured in this piece, BlueRock Therapeutics, is a portfolio company of Leaps by Bayer, which is a sponsor of Leaps.org. BlueRock was acquired by Bayer Pharmaceuticals in 2019. Leaps by Bayer and other sponsors have never exerted influence over Leaps.org content or contributors.