Recent advancements in engineering mean that the first preclinical trials for an artificial kidney could happen as soon as 18 months from now
Like all those whose kidneys have failed, Scott Burton’s life revolves around dialysis. For nearly two decades, Burton has been hooked up (or, since 2020, has hooked himself up at home) to a dialysis machine that performs the job his kidneys normally would. The process is arduous, time-consuming, and expensive. Except for a brief window before his body rejected a kidney transplant, Burton has depended on machines to take the place of his kidneys since he was 12-years-old. His whole life, the 39-year-old says, revolves around dialysis.
“Whenever I try to plan anything, I also have to plan my dialysis,” says Burton says, who works as a freelance videographer and editor. “It’s a full-time job in itself.”
Many of those on dialysis are in line for a kidney transplant that would allow them to trade thrice-weekly dialysis and strict dietary limits for a lifetime of immunosuppressants. Burton’s previous transplant means that his body will likely reject another donated kidney unless it matches perfectly—something he’s not counting on. It’s why he’s enthusiastic about the development of artificial kidneys, small wearable or implantable devices that would do the job of a healthy kidney while giving users like Burton more flexibility for traveling, working, and more.
Still, the devices aren’t ready for testing in humans—yet. But recent advancements in engineering mean that the first preclinical trials for an artificial kidney could happen as soon as 18 months from now, according to Jonathan Himmelfarb, a nephrologist at the University of Washington.
“It would liberate people with kidney failure,” Himmelfarb says.
An engineering marvel
Compared to the heart or the brain, the kidney doesn’t get as much respect from the medical profession, but its job is far more complex. “It does hundreds of different things,” says UCLA’s Ira Kurtz.
Kurtz would know. He’s worked as a nephrologist for 37 years, devoting his career to helping those with kidney disease. While his colleagues in cardiology and endocrinology have seen major advances in the development of artificial hearts and insulin pumps, little has changed for patients on hemodialysis. The machines remain bulky and require large volumes of a liquid called dialysate to remove toxins from a patient’s blood, along with gallons of purified water. A kidney transplant is the next best thing to someone’s own, functioning organ, but with over 600,000 Americans on dialysis and only about 100,000 kidney transplants each year, most of those in kidney failure are stuck on dialysis.
Part of the lack of progress in artificial kidney design is the sheer complexity of the kidney’s job. Each of the 45 different cell types in the kidney do something different.
Part of the lack of progress in artificial kidney design is the sheer complexity of the kidney’s job. To build an artificial heart, Kurtz says, you basically need to engineer a pump. An artificial pancreas needs to balance blood sugar levels with insulin secretion. While neither of these tasks is simple, they are fairly straightforward. The kidney, on the other hand, does more than get rid of waste products like urea and other toxins. Each of the 45 different cell types in the kidney do something different, helping to regulate electrolytes like sodium, potassium, and phosphorous; maintaining blood pressure and water balance; guiding the body’s hormonal and inflammatory responses; and aiding in the formation of red blood cells.
There's been little progress for patients during Ira Kurtz's 37 years as a nephrologist. Artificial kidneys would change that.
UCLA
Dialysis primarily filters waste, and does so well enough to keep someone alive, but it isn’t a true artificial kidney because it doesn’t perform the kidney’s other jobs, according to Kurtz, such as sensing levels of toxins, wastes, and electrolytes in the blood. Due to the size and water requirements of existing dialysis machines, the equipment isn’t portable. Physicians write a prescription for a certain duration of dialysis and assess how well it’s working with semi-regular blood tests. The process of dialysis itself, however, is conducted blind. Doctors can’t tell how much dialysis a patient needs based on kidney values at the time of treatment, says Meera Harhay, a nephrologist at Drexel University in Philadelphia.
But it’s the impact of dialysis on their day-to-day lives that creates the most problems for patients. Only one-quarter of those on dialysis are able to remain employed (compared to 85% of similar-aged adults), and many report a low quality of life. Having more flexibility in life would make a major different to her patients, Harhay says.
“Almost half their week is taken up by the burden of their treatment. It really eats away at their freedom and their ability to do things that add value to their life,” she says.
Art imitates life
The challenge for artificial kidney designers was how to compress the kidney’s natural functions into a portable, wearable, or implantable device that wouldn’t need constant access to gallons of purified and sterilized water. The other universal challenge they faced was ensuring that any part of the artificial kidney that would come in contact with blood was kept germ-free to prevent infection.
As part of last year’s KidneyX Prize, a partnership between the U.S. Department of Health and Human Services and the American Society of Nephrology, inventors were challenged to create prototypes for artificial kidneys. Himmelfarb’s team at the University of Washington’s Center for Dialysis Innovation won the prize by focusing on miniaturizing existing technologies to create a portable dialysis machine. The backpack sized AKTIV device (Ambulatory Kidney to Increase Vitality) will recycle dialysate in a closed loop system that removes urea from blood and uses light-based chemical reactions to convert the urea to nitrogen and carbon dioxide, which allows the dialysate to be recirculated.
Himmelfarb says that the AKTIV can be used when at home, work, or traveling, which will give users more flexibility and freedom. “If you had a 30-pound device that you could put in the overhead bins when traveling, you could go visit your grandkids,” he says.
Kurtz’s team at UCLA partnered with the U.S. Kidney Research Corporation and Arkansas University to develop a dialysate-free desktop device (about the size of a small printer) as the first phase of a progression that will he hopes will lead to something small and implantable. Part of the reason for the artificial kidney’s size, Kurtz says, is the number of functions his team are cramming into it. Not only will it filter urea from blood, but it will also use electricity to help regulate electrolyte levels in a process called electrodeionization. Kurtz emphasizes that these additional functions are what makes his design a true artificial kidney instead of just a small dialysis machine.
One version of an artificial kidney.
UCLA
“It doesn't have just a static function. It has a bank of sensors that measure chemicals in the blood and feeds that information back to the device,” Kurtz says.
Other startups are getting in on the game. Nephria Bio, a spinout from the South Korean-based EOFlow, is working to develop a wearable dialysis device, akin to an insulin pump, that uses miniature cartridges with nanomaterial filters to clean blood (Harhay is a scientific advisor to Nephria). Ian Welsford, Nephria’s co-founder and CTO, says that the device’s design means that it can also be used to treat acute kidney injuries in resource-limited settings. These potentials have garnered interest and investment in artificial kidneys from the U.S. Department of Defense.
For his part, Burton is most interested in an implantable device, as that would give him the most freedom. Even having a regular outpatient procedure to change batteries or filters would be a minor inconvenience to him.
“Being plugged into a machine, that’s not mimicking life,” he says.
Some argue that transgender females should be banned from competing with women in sports, while others think such bans are unfair, as the NCAA and other organizations try to keep up with research on how testosterone affects performance.
However, in 18 states, many of which are politically conservative, laws prohibit transgender students from participating in sports consistent with their gender identity, according to the Movement Advancement Project, an independent, nonprofit think tank based in Boulder, Colo., that focuses on the rights of LGBTQ people. The first ban was passed in Idaho in 2020, although federal district judges have halted this legislation and a similar law in West Virginia from taking effect.
Proponents of the bans caution that transgender females would have an unfair biological advantage in competitive school sports with other girls or women as a result of being born as stronger males, potentially usurping the athletic accomplishments of other athletes.
“The future of women’s sports is at risk, and the equal rights of female athletes is being infringed,” said Penny Nance, CEO and president of Concerned Women for America, a legislative action committee in D.C. that seeks to impact culture to promote religious values.
“As the tidal wave of gender activism consumes sports from the Olympics on down, a backlash is being felt as parents are furious about the disregard for their daughters who have worked very hard to achieve success as athletes,” Nance added. “Former athletes, whose records are being shattered, are demanding answers.”
Meanwhile, opponents of the bans contend that they bar transgender athletes from playing sports with friends and learning the value of teamwork and other life lessons. These laws target transgender girls most often in kindergarten through high school but sometimes in college as well. Many local schools and state athletic associations already have their own guidelines “to both protect transgender people and ensure a level playing field for all athletes,” according to the Movement Advancement Project’s website. But statewide bans take precedence over these policies.
"It’s easy to sympathize on some level with arguments on both sides, and it’s likely going to be impossible to make everyone happy,” said Liz Joy, a past president of the American College of Sports Medicine.
In January, the National Collegiate Athletic Association (NCAA), based in Indianapolis, tried to sort out the controversy by implementing a new policy. It requires transgender students participating in female sports to prove that they’ve been taking treatments to suppress testosterone for at least one year before competition, as well as demonstrating that their testosterone level is sufficiently low, depending on the sport, through a blood test.
Then, in August, the NCAA clarified that these athletes also must take another blood test six months after their season has started that shows their testosterone levels aren’t too high. Additional guidelines will take effect next August.
Even with these requirements, “there is no plan that is going to be considered equitable and fair to all,” said Bradley Anawalt, an endocrinologist at the University of Washington School of Medicine. Biologically, he noted, there is still some evidence that a transgender female who initiates hormone therapy with estrogen and drops her testosterone to very low levels may have some advantage over other females, based on characteristics such as hand and foot size, height and perhaps strength.
Liz Joy, a past president of the American College of Sports Medicine, agrees that allowing transgender athletes to compete on teams of their self-identifying gender poses challenges. “It’s easy to sympathize on some level with arguments on both sides, and it’s likely going to be impossible to make everyone happy,” said Joy, a physician and senior medical director of wellness and nutrition at Intermountain Healthcare in Salt Lake City, Utah. While advocating for inclusion, she added that “sport was incredibly important in my life. I just want everyone to be able to benefit from it.”
One solution may be to allow transgender youth to play sports in a way that aligns with their gender identity until a certain age and before an elite level. “There are minimal or no potential financial stakes for most youth sports before age 13 or 14, and you do not have a lot of separation in athlete performance between most boys and girls until about age 13,” said Anwalt, who was a reviewer of the Endocrine Society’s national guidelines on transgender care.
Myron Genel, a professor emeritus and former chief of pediatric endocrinology at Yale School of Medicine, said it’s difficult to argue that height gives transgender females an edge because in some sports tall women already dominate over their shorter counterparts.
He added that the decision to allow transgender females to compete with other girls or women could hinge on when athletes began taking testosterone blockers. “If the process of conversion from male to female has been undertaken in the early stages of puberty, from my perspective, they have very little unique advantage,” said Genel, who advised the International Olympic Committee (IOC), based in Switzerland, on testosterone limits for transgender athletes.
Because young athletes’ bodies are still developing, “the differences in natural abilities are so massive that they would overwhelm any advantage a transgender athlete might have,” said Thomas H. Murray, president emeritus of The Hastings Center, a pioneering bioethics research institute in Garrison, New York, and author of the book “Good Sport,” which focuses on the ethics and values in the Olympics and other competitions.
“There’s no good reason to limit the participation of transgender athletes in the sports where male athletes don’t have an advantage over women,” such as sailing, archery and shooting events, Murray said. “The burden of proof rests on those who want to restrict participation by transgender athletes. They must show that in this sport, at this level of competition, transgender athletes have a conspicuous advantage.”
Last year, the IOC issued a new framework emphasizing that the Olympic rules related to transgender participation should be specific to each sport. “This is an evolving topic and there has been—as it will continue to be—new research coming out and new developments informing our approach,” and there’s currently no consensus on how testosterone affects performance across all sports, an IOC spokesperson told Leaps.org.
Many of the new laws prohibiting transgender people from competing in sports consistent with their gender identity specifically apply to transgender females. Yet, some experts say the issue also affects transgender males, nonbinary and intersex athletes.
“There has been quite a bit of attention paid to transgender females and their participation in biological female sports and almost minimal focus on transgender male competition in male sports or in any sports,” said Katherine Drabiak, associate professor of public health law and medical ethics at University of South Florida in Tampa. In fact, “transgender men, because they were born female, would be at a disadvantage of having less lean body mass, less strength and less muscular area as a general category compared to a biological male.”
While discussing transgender students’ participation in sports, it’s important to call attention to the toll that anti-transgender legislation can take on these young people’s well-being, said Jonah DeChants, a research scientist at The Trevor Project, a suicide prevention and mental health organization for LGBTQ youth. Recent polling found that 85 percent of transgender and nonbinary youth said that debates around anti-transgender laws had a negative impact on their mental health.
“The reality is simple: Most transgender girls want to play sports for the same reasons as any student—to benefit their health, to have fun, and to build connection with friends,” DeChants said. According to a new peer-reviewed qualitative study by researchers at The Trevor Project, many trans girls who participated in sports experienced harassment and stigma based on their gender identity, which can contribute to poor mental health outcomes and suicide risk.
In addition to badminton, O'Connor played other sports such as volleyball, and she plans to become an assistant coach or manager of her old high school's badminton team.
Ashley O'Connor
However, DeChants added, research also shows that young people who reported living in an accepting community, had access to LGBTQ-affirming spaces, or had social support from family and friends reported significantly lower rates of attempting suicide in the past year. “We urge coaches, educators and school administrators to seek LGBTQ-cultural competency training, implement zero tolerance policies for anti-trans bullying, and create safe, affirming environments for all transgender students on and off the field,” DeChants said.
O’Connor said her experiences on the athletic scene have been mostly positive. The politics of her community lean somewhat liberal, and she thinks it’s probably more supportive than some other areas of the country, though she noted the local library has received threats for hosting LGBTQ events. In addition to badminton, she also played baseball, lacrosse, volleyball, basketball and hockey. In the spring, she plans to become an assistant coach or manager for the girls’ badminton team at her old high school.
“When I played badminton, I never got any direct backlash from any coaches, competitors or teammates,” she said. “I had a few other teammates that identified as trans or nonbinary, [and] nearly all of the people I ever interacted with were super pleasant and treated me like any other normal person.” She added that transgender athletes “have aspirations. We have wants and needs. We have dreams. And at the end of the day, we just want to live our lives and be happy like everyone else.”
