This week, I covered a fascinating effort to preserve organs outside the body. There’s a huge shortage of donor organs, and one of the main reasons is time—they survive only a matter of hours outside the body, even when they’re kept on ice.

Doctors dream of organ banks—stores of human organs that can be preserved for days, weeks, months, or even longer. That would allow them to run tests on organs, find the best matches for them, and transport the organs to those recipients.

In new research, one team has been able to supercool the kidneys of pigs—animals whose organs are of a similar size to human ones—and preserve them for days. The kidneys survived being stored at −4 °C (25 °F) and eventually reimplanted back into pigs. And that’s just the latest development in a field that is positively buzzing.

It has proved super difficult to freeze organs. Once ice forms in them, they’re done. The ice crystals create all kinds of damage and render the organs unusable. That hasn’t stopped many researchers from trying.

Some have focused on cryopreservation—rapid extreme cooling that essentially leaves cells in a glasslike state. This process is now routine for eggs, sperm, and embryos, which are cooled to −196 °C in less than two seconds and can be used even after decades in storage.

No one has managed to cryopreserve and thaw human organs for transplantation. But plenty of human bodies and brains have been stored at ultra-low temperatures in the hope that they might one day be rewarmed and brought back to life. (You can read more about why some people opt for cryonics here.)

In March, I wrote about Stephen L. Coles, a gerontologist who had opted to cryopreserve his own brain. After the scientist died in 2014, his body was taken to Alcor, a cryonics facility in Arizona. A team at the facility removed Coles’s head, perfused his brain with cryoprotective chemicals (which work like antifreeze), removed the brain from the skull, and cooled it to −146 °C.

When Coles’s friend Greg Fahy, a cryobiologist, studied pieces of his brain years later, he found that the brain cells, which had shrunk, “bounced back” once they were rewarmed. But that doesn’t mean the cells are alive, or that it might one day be possible to reanimate the brain. As Matthew Powell Palm of Texas A&M told me at the time: “There are so many ways those neurons could be toast.”

Powell Palm is working on other ways to preserve organs. It was he, along with his colleagues, who managed to store supercooled pig kidneys and successfully transplant them, in a study described as “a landmark achievement.” Those organs did better than kidneys stored on ice, he says.

His approach didn’t require cryoprotectants. But other teams are exploring potential chemical cocktails that might allow them to store organs at lower temperatures, potentially for longer periods of time. (More on this in The Checkup soon!)

Another way to prolong the lifespan of an organ is to use a machine that perfuses it with nutrients, mimicking what happens inside the body. Machine perfusion devices have become more commonly used over the last decade or so and are typically used to maintain livers and kidneys for up to about 24 hours.

Researchers are now adapting this protocol for a growing list of organs, even eyeballs—a recent feat that might enable whole-eye transplants. In March, I went to visit scientists in Valencia who had developed a perfusion system for uteruses. They had used their device—which they nicknamed “Mother”—to keep a human uterus alive for a day.

It’s an exciting time for organ preservation. Keep an eye out for more coverage from MIT Technology Review in the coming weeks.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

When it comes to organ donation, time is everything. As soon as an organ has been carefully removed from a donor’s body, it starts to deteriorate. Surgeons have a matter of hours to get it into a recipient. Leave it too long and the organ will become unusable.

In most cases, organs will be kept on ice during that time, at around 4 °C (39 °F). They cannot be frozen—in previous attempts, ice has formed, causing all kinds of damage.

Matthew Powell Palm at Texas A&M University and his colleagues have an alternative solution—a device that allows organs to be cooled to -4 °C (25 °F) without forming any ice.

Now, in new research with pig organs, his team has shown that kidneys, at least, can be supercooled and preserved in the device for days. Once rewarmed, the organs have been successfully transplanted into animals, and they seem to do better than organs kept on ice.

The work represents “a landmark achievement,” says Kevin Myer, president and CEO of LifeGift, an organ procurement organization based in Texas, who was not involved in the research.

Cooling organs

Powell Palm hopes this approach could ultimately help ease the organ shortage crisis. Today, there are more than 104,000 people waiting for a kidney transplant in the US alone. It is estimated that 17 people die every day in the US while waiting for a transplant. That’s partly due to a lack of donated kidneys, but it’s also because many of those that are available never make it to a recipient. In some years, around one in three donated kidneys end up being discarded, often because they end up too degraded to use by the time they reach a recipient. Kidneys can be stored on ice for around 24 hours or placed in devices that aim to mimic the conditions of the body, also for up to around 24 hours. That’s not always long enough to find a suitable recipient and transport the organ, says Myer.

Scientists around the world have been working on ways to store organs for longer by cooling them to even chillier temperatures. Cooling an organ slows its metabolism—the colder you go, the greater the effect, and the longer you can store it.

We’ve long been able to successfully cryopreserve eggs, sperm, and embryos, but it’s much harder to freeze large organs. Teams have been exploring various temperatures and cryoprotectants (chemicals that essentially work like antifreeze), but so far no one has been able to freeze human organs for transplantation.  

As a thermodynamicist, Powell Palm explored another approach. By keeping an organ submerged at a constant pressure, it should be possible to prevent the formation of ice at temperatures a little below 0 °C, without the need for cryoprotectants (which might have side effects and would need to be approved before being used in human transplants). 

To test this theory, Powell Palm and his colleagues have created a device that does just that. The device itself is essentially a hermetically sealed chamber with a transparent lid. At its base is a device that monitors the organ’s temperature and checks for the formation of ice. Organs are submerged in a solution that is already commonly used to preserve them for transplant. “I always describe this as low-tech high science,” says Powell Palm. “A lot of work has gone into understanding the … kinetics at play in this system, but ultimately … it’s quite simple.”

Supercooled kidneys

To test their device, Powell Palm and his colleagues first removed single kidneys from pigs. The organs were flushed with the same commonly used solution to remove the blood, just as transplant organs are. The team then kept some kidneys on ice for either two hours or 24 hours, to mimic standard conditions used in human transplantation. They also put some of the removed kidneys in their device for 24, 48, or 72 hours.

The stored kidneys were then each transplanted back into the original donor pigs. Each pig’s second kidney was removed in the same procedure, leaving each animal with only the kidney that had been stored, and reimplanted.

Once the 24-hour supercooled kidneys were transplanted, they immediately began producing urine—a key indication that they were working. The team members also measured other markers of kidney function and found that the organs appeared to be working normally within about 10 days of being transplanted.

That’s slower than kidneys stored on ice for two hours but much quicker than kidneys kept on ice for 24 hours, says Powell Palm.

The organs that were kept supercooled for 48 and 72 hours performed similarly, he says. “Even at three days—triple the clinical standard—we’re getting recovery that is faster than … [what has been] the gold standard for the last three decades,” he says. “So we’re really, really pumped about this.”

“It is impressive,” says Heidi Yeh, a transplant surgeon at Mass General Brigham for Children, who also researches organ preservation technologies. “Often kidneys that have been stored for 48 hours [in other studies] take a week or two before they start working again.”

Organs that grow

The supercooled organs seem to work well in the long term, too. Over a 30-day period, the pigs grew by around 30%—and the kidneys grew with them, almost doubling in size to compensate for both the pigs’ growth and the lack of a second kidney. The team monitored one of the pigs for 200 days before removing and analyzing its kidney. Even at that point the organ looked healthy, says Powell Palm. He and his colleagues presented the findings at the American Transplant Congress in Boston last month.

Earlier this year, researchers in Canada showed they could also cool pig kidneys to below-zero temperatures and transplant them into pigs. The team’s protocol included the use of a cryoprotectant, and organs were stored for up to 48 hours before being transplanted into pigs. Those organs survived for a week.

In supercooling organs for 72 hours and showing that they do well for 30 days or more, Powell Palm and his colleagues have broken new ground. “It’s the first time this has ever been reported in history,” he says.

Those extra hours could make all the difference, says Myer of LifeGift. The advance could give doctors more time to evaluate the kidneys, match them to the most suitable donors, and physically get the organs to their intended recipients in time. It could enable international donations and open up cheaper transport options, he adds. “Right now, with kidney transplantation the assumed limit is 18 to 24 hours,” he says. “If we can get up to 72 hours … that would change everything.”

Powell Palm and his colleagues think they may even be able to go beyond 72 hours. In preliminary studies, organs that had been stored for up to 120 hours appeared healthy, although those organs have not yet been transplanted.

And because the process doesn’t require any cryoprotective chemicals, the team members are hoping for an accelerated approval from the US Food and Drug Administration, which would allow them to test the device in human transplantations.

The storage device is simple and compact, so Powell Palm thinks it will be easy to transport. It hasn’t been tested for air travel yet, but it has been used to take supercooled kidneys across the US in the back of a Kia Sorento, he says: “From a stability perspective, we view this as an even higher bar.”

Powell Palm and his colleague Sebastian Giwa plan to launch a company dedicated to developing the technology, along with other protocols that “stop biological time,” in the coming months, he says.

Perimenopause has entered the chat. Perimenopause—and its better-known relative, menopause—used to be considered taboo. Not anymore, thanks at least in part to TV doctors and social media influencers. Perhaps it’s my age, but these days, both my algorithm and my conversations with friends increasingly swing toward perimenopause.

Menopause is defined as the life stage that occurs a year after a person has had their last period. Perimenopause is the sometimes years-long period before that point, which can also feature all the symptoms we’d typically associate with menopause.

Today, information about perimenopause is more prevalent and accessible than ever. If you’re a woman in your 40s and you’re not feeling 100%, chances are there’ll be someone online ready to tell you you’re in perimenopause. And that you might want to start spending your money on blood tests, apps, and supplements or demanding hormone replacement therapy. But as regular readers might have guessed by this point, it’s not that simple.

Perimenopause tends to start around the age of 46 or 47. It’s during this time that many women start to experience some symptoms like hot flashes, irregular or unusually heavy periods, or anxiety, for example. And it can be heavy going. “Often symptoms are at their worst in the perimenopause,” says Mary Ann Lumsden, former president of the International Menopause Society.

That’s because hormones can fluctuate wildly. Levels of estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone can roller-coaster before leveling off after menopause. And that’s why, despite what some marketers will claim, there is no test for perimenopause.

“You can’t interpret hormone [measures] because they change so much,” says Lumsden. “And that is quite normal.”

That doesn’t mean women should have to put up with symptoms. But exactly how those symptoms are treated is another topic that has been clouded by misinformation.

Last week, I told a friend about some unusually bad pelvic pain I’d experienced. Her immediate advice was to find out if I was perimenopausal and, if I was, to request hormone replacement therapy (HRT) as soon as possible. If my doctor wouldn’t prescribe it, she continued, I should simply find another doctor who would.

This line of thinking has been heavily promoted on social media platforms, says Paula Briggs, a former chair of the British Menopause Society who currently leads the menopause service at Liverpool Women’s Hospital. But it’s not helpful.

HRT is essentially designed to top up or replace hormones like estrogen and progesterone, which naturally decline around menopause. There are lots of different drugs that can be taken in lots of different ways and at various doses.

While it does come with some risks and won’t suit everyone, HRT can be immensely helpful for many menopausal women. Not only can it help with many of the common symptoms of menopause, but it can also help prevent osteoporosis and maintain muscle strength.

But these drugs were trialed in, and approved for, menopausal women, says Lumsden. They won’t have the same effects in perimenopausal women. “If you give standard HRT, it may well get swamped by [the woman’s] own hormone production,” she says.

HRT can also cause abnormal bleeding in perimenopausal women, says Briggs.

She’s concerned about the messaging on perimenopause that is being promoted on social media. Particularly worrisome, she says, is the way younger women are being encouraged to assume they are perimenopausal and seek out HRT treatment.

“It’s almost cult-like, this idea that everybody must have HRT,” she says.

And then there are the supplements. There’s been an explosion in marketing for vitamins and supplements specifically targeted to middle-aged and menopausal women. But the evidence for these, too, is either limited or nonexistent. “I can’t see a mechanism for a lot of them,” says Lumsden.

Women who take these supplements don’t always know what they’re getting. Some of Lumsden’s patients have told her they take testosterone supplements to manage their symptoms. But blood tests revealed no increase in testosterone levels. “Whatever they’re getting, it’s not testosterone,” she says.

At any rate, not all the symptoms women experience in midlife can be blamed on hormones. The lengthy lists of perimenopause symptoms shared on social media include fatigue, brain fog, aches and pains, digestive issues, and more. “These do not link closely to the obvious menstrual cycle changes and hormone changes … across menopause,” says Nanette Santoro, a professor of obstetrics and gynecology at the University of Colorado Anschutz who studies menopause.

If you’re experiencing any symptoms, it’s worth getting them checked out to make sure they’re not being caused by something else. My own pelvic pain, for example, is almost definitely the result of endometriosis—a condition that can be made worse by HRT, Lumsden tells me.

At any rate, by the time women reach their 40s, many are already juggling care for children and aging parents, often while holding down a job (and dealing with pressures from societies that don’t appear to value older women). It’s an exhausting time—and not all of that exhaustion can be blamed on hormones.

As Santoro puts it: “Attributing everything unpleasant that happens to a woman over 35 to perimenopause is not based on any scientific evidence.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

Ties van der Meer doesn’t know how many siblings he has.

The 47-year-old was conceived at a private fertility clinic in the Netherlands using sperm provided by an anonymous donor. After the Netherlands banned anonymous donation in 2004, the doctor who ran the clinic destroyed records that might have identified those donors, he says.

He describes the situation as “problematic.” Children have a right to know their biological parents, he says. While he did ultimately track down one sibling, who helped him identify his father along with other genetic relatives, he may have others he’ll never find.

Other donor-conceived people who have been able to track down siblings have found they have tens or even hundreds of them. One donor-conceived woman who found 25 half-siblings over the course of seven years told the Guardian, “It does make you feel a bit mass-produced.”

We need international limits on the number of children a single donor can contribute to, a European fertility organization argued yesterday. At a conference in London, members laid out plans to start with a Europe-wide limit.

Today many countries, including the UK, have banned anonymous egg and sperm donation. But anonymity can’t be guaranteed even in places where it is technically allowed. Genetic tests offered by companies like Ancestry and 23andMe, along with genetic registries, have made it much easier for donor-conceived people to find parents and siblings who share their genes.

And because sperm can be frozen and stored for years before it is eventually used, the current set-up can result in situations where donor-conceived people discover the identity of a genetic parent only after the person’s death. They might also find that they have siblings of very different ages, all around the world.

Some people are finding hundreds of siblings. Sperm from Jonathan Meijer, a Dutch man who began donating in 2007, was used to conceive between 550 and 600 children. (Stichting Donorkind, a foundation and advocacy group for donor-conceived people that’s chaired by van der Meer, took him to court, and he was ordered to stop donating in 2023.)

Stories like these can be distressing for donor-conceived people. And there are other reasons why limits are considered important. The offspring of a prolific donor might be at risk of unknowingly forming romantic or sexual relationships, for instance. And some people are concerned that a donor with a harmful genetic mutation might pass that down to many children.

This is unlikely, given the level of screening that most donors undergo. But it has happened. A man who donated his sperm to a sperm bank in Denmark was found to have a genetic mutation that significantly increased the risk of multiple cancers. But his sperm had already been used to conceive at least 197 children across Europe. Some of those children developed cancer. Some died.

Many countries already have legal limits for donors. In Malta and Cyprus, for example, both egg and sperm donors are allowed to contribute to the birth of just a single child, according to data presented at the European Society of Human Reproduction and Embryology (ESHRE) meeting in London on July 8.

Other countries set limits based on the number of families a single donor can contribute to, allowing recipients to have children who share a genetic link. In the UK, that limit is set at 10 families per donor.

But these limits are difficult to enforce, partly because donated gametes don’t necessarily stay in their original country. In Denmark, the national limit is set at 12 families. But the country is a major exporter of sperm. In the UK, for example, more than half of sperm donations in 2020 were imported—with most of those coming from either Denmark or the US.

“The only thing that really makes sense is a transnational limit,” Jackson Kirkman-Brown, a professor of reproductive biology at the University of Birmingham, said at the meeting.

Kirkman-Brown and his colleagues have spent months putting together a document that represents ESHRE’s position on these limits. After consulting with fertility specialists, clinics, sperm and egg banks, donors, and donor-conceived people, the team has developed a plan to start with a Europe-wide limit on sperm and egg donations.

ESHRE is calling on sperm and egg banks, as well as fertility clinics, to respect an initial limit of 50 families per donor. That’s still very high, according to a handful of people I spoke to at the meeting. But at least it’s a start.

Europe should move toward setting limits at 15 families per donor, Kirkman-Brown said. “We may find that 15 is also too high,” says Vasanti Jadva, who studies the psychological well-being of people conceived using donated eggs, sperm, and embryos at City St George’s in London. “We still don’t know what the right number is.”

It will be difficult to enforce these limits, too. And if they end up limiting the supply of donor sperm, there’s a chance that some people will turn to unregulated sperm donations from people who do not undergo health screening. Unregulated donations can lead to other problems for prospective parents, including the possibility that donors will seek parental rights over the children conceived using their sperm.

And it will be even harder to establish international limits. When I asked the American Society of Reproductive Medicine for its thoughts on ESHRE’s proposed limits, a representative directed me to a guidance document saying “it has been suggested” that for a population of 800,000, single donors should be limited to “no more than 25 births” in order to avoid the risk that relatives will have children together. (Considering the US has a population of over 340 million, the total figure could be pretty high, but many sperm banks opt to limit the number of families contributed to by a single donor at around 25.)

Van der Meer thinks that even a limit of five families from a single donor would be high. International donation makes it even harder for donor-conceived people to connect with genetic relatives, so the limit for international contributions should be set at two families, he says.

Still, he thinks ESHRE’s suggested limit is a “positive first step.” Van der Meer has managed to track down a sibling, his father, and nephews, aunts, and uncles. He hopes that future policies respect the rights of donor-conceived children to know, and be in contact with, their genetic relatives.

“But,” he says, “you have to start somewhere.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

This week, I covered the story of Casey Harrell—a man with ALS who is “the first power user” of a brain implant, according to the researchers who worked with him. Harrell is paralyzed and unable to speak coherently without the device. He has now spent almost three years using a brain-computer interface (BCI) that enables him to “speak,” surf the web, and perform his job as a climate activist, largely independently.

Since Harrell was implanted with the device, in July 2023, a team at the University of California, Davis, has worked with him to adjust and improve its offerings. They’ve refined its accuracy, for example. And they’ve introduced settings including a privacy mode and a “profanity filter” that lets Harrell talk to his daughter without risking accidental swearing.

Harrell told me that, for him, the device is “nothing short of revolutionary!” It has enabled him to maintain an income, reconnect with friends and family, and read to his daughter. 

The team that developed his BCI is one of several working on ways to use technology to allow people with paralysis to communicate, engage with the online world, and regain some independence. And Harrell is one of a growing number of people volunteering their brains to, as he puts it, “pay it forward and do the scientific research … [and] get some personal benefit.”

Over the past couple of years, the number of BCI trial volunteers has soared. This year, China became the first country to approve a BCI for medical use. Advances in technology are allowing engineers to provide more features than ever. BCI research is properly taking off.

I should first point out that BCIs come in different forms. Harrell’s device includes a set of electrodes embedded in his brain that pick up the electrical activity associated with speech. Those electrodes are connected to two docking ports on top of his head that can be plugged into a computer.

That computer is loaded with software trained to decode his brain signals into phonemes (units of sound in speech) and predict what Harrell wants to say. He can then use an eye gaze tracker to make any corrections before the speech is played out loud.

But some BCIs don’t need to be “plugged in”—they’re fully implanted and wireless. Others are less invasive; they might involve placing wired electrodes on the surface of the brain or simply wearing a cap of electrodes, for example. There are trade-offs—the closer you get to the neurons you want to record from, the better your signal will be. But generally speaking, the more invasive the surgery, the higher the risk of complications.

BCIs can also have different functions. Harrell has ALS, but most BCIs in use today are sitting in the brains of people with spinal cord injuries. Typically, these individuals have some degree of paralysis; for example, they may be unable to move their arms and legs, but their face and ability to speak are unaffected. In those cases, BCIs can be used to control other kinds of devices that might help with mobility.

In 2024, Michelle Patrick-Krueger, then at the University of Houston, and her colleagues published a roundup of all trials of BCIs conducted between 1998, which is when they believe the first device was implanted, and the end of 2023. They identified 21 research groups that, among them, had trialed BCIs in a total of 67 volunteers.

“Since then, that number has increased a lot,” says Mariska Vansteensel, a BCI researcher at University Medical Center Utrecht. In January, Neuralink (the BCI company founded by trillionaire Elon Musk) announced that it has implanted 21 people with its device in the past two years.

Synchron, another BCI company, is currently testing its devices in trials in North America and Australia. Shanghai-based Neuracle has been trialing a BCI since November 2024, and it recently obtained approval for the device to be used outside of clinical trials. Precision Neuroscience, cofounded by a former co-creator of rival Neuralink, is also trialing its BCI, which sits on the surface of the brain.

At the same time, academic research has continued. The UC Davis team that worked with Harrell is part of BrainGate—a BCI research effort that has been running for the past two decades. Other academic teams are exploring a variety of devices, from the fully implanted to the minimally invasive.

Since 2024, when Patrick-Krueger’s paper was published, the number of people who have been implanted with a brain electrode has more than doubled, according to Vansteensel. “My current estimation would be around 150 people,” she says.

The technology is improving too. Take the BrainGate trial, for example. The first 17 years of that trial focused on the use of what researchers call “point-and-click” communication—allowing users to control a cursor and “click” with their brain activity. But in recent years the team has pivoted toward decoding speech, says David Brandman, the lead investigator on the team (and the person who implanted Harrell’s electrodes). Today, Harrell’s device uses a voice clone—the speech it produces is based on previous recordings of Harrell’s voice.

But BCIs are still experimental. And plenty of questions remain about who might benefit from them—and how long the devices will last. So far, most BCIs have been implanted in people with spinal cord injuries. We know even less about how they might benefit other people who have ALS, for example. In some cases where the devices initially helped people with ALS—even someone who was completely locked in—the BCIs eventually stopped working. And scientists don’t really know why.

The only way they’ll find out is through more research—and the participation of volunteers like Harrell. So it’s exciting to see trials truly take off. And I promise I’ll update you on where they stand two years from now.

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

Casey Harrell has had a set of electrodes embedded in his brain for almost three years. Harrell, who has amyotrophic lateral sclerosis (ALS) and is paralyzed, first used his brain-computer interface (BCI) to “speak” sentences with the help of a research team in 2023.

Since then, Harrell has clocked thousands of hours of use. He can use the device largely independently, once he’s been “plugged in” with the help of a carer. His team has added new features to it, and Harrell also uses it to surf the web and perform his job.

“Living with a disease like ALS, you are supposed to have diminished dreams. I do not,” Harrell tells MIT Technology Review. “Any one of these things would be an absolute godsend of improvement. To have all of them, and many, many more, is truly revolutionary.” 

Within the first 22.6 months after the device was implanted, Harrell had used it for more than 3,800 hours at home without any researchers present, the team reported today in the journal Nature Medicine. “He’s the first power user of a speech BCI,” says team member Sergey Stavisky, a neuroengineer at the University of California, Davis.

Decoding speech

Three years ago, Harrell entrusted David Brandman, an associate professor of neurological surgery at the University of California, Davis, and his colleagues with his brain. Harrell, who was 45 at the time, had already been diagnosed with ALS, a degenerative disease that robs people of the use of their muscles.

Harrell was dependent on others to control his wheelchair and to dress and feed him. He had difficulty speaking; people struggled to understand what he was saying. Then Brandman and his colleagues asked if he’d like to trial a brain implant that might help him communicate. “The industry was [on the] cusp of a transformation, and I wanted to be part of it,” says Harrell. He signed up.

In July 2023, during a five-hour operation, doctors implanted four arrays of 64 electrodes each into his brain. Each pair of arrays was wired to a “pedestal” connection point—creating two docking locations on the exterior of his skull to connect the electrodes to a computer.

The team had long been working on developing algorithms to decode brain activity into speech. Their system works by recording activity from the speech motor cortex—a region of the brain responsible for the movements that allow us to speak.

“There are 39 phonemes that make up all the sounds in the [American] English language,” says Nicholas Card, a neuroengineer at UC Davis and member of the team. Mapping neural activity related to producing each of those phonemes can allow the team to create a personalized speech decoder and software that can “speak” those words. “We first go from brain data to phonemes, and then from phonemes to words,” he says.

They started using the device around a month after the surgery. The team got Harrell’s speech decoder working on the first day, says Card. On that day in August, Harrell used the device to speak with a 50-word vocabulary, and 99.6% of the words were as he’d intended. That vocabulary was later expanded to 125,000 words with 97.5% accuracy.

At the time, it was unclear how long the device might last. Brain-computer interfaces are still new—not many people have had them implanted for long periods of time. Scar tissue can form around electrodes in a person’s brain, interfering with their ability to pick up neural activity, for example. But that doesn’t seem to be the case for Harrell.

Power user

In another advance, Harrell is now able to use the device more independently. In 2023, members of the research team would have to visit Harrell at his home and physically connect and disconnect him from the device on the days he wanted to use it. Not anymore. The team has since automated more of the system—today, Harrell’s care partner can don and doff it for him. “He’ll wake up, get plugged in, and just get going,” says Stavisky.

This is important, says Mariska Vansteesel, a BCI researcher at Utrecht Medical Center who was not involved in the trial. “For these technologies to be relevant for patients, we really need to test them in settings in which they will eventually be used … to demonstrate that it has value, that it’s usable, and that it functions well without the constant involvement of a research team,” she says.

The team has also worked to improve the system itself. It is now 99% accurate, says Stavisky. Harrell can also control a cursor—a game changer that enables him to use his personal computer to send text messages and emails, surf the web, and keep up with his job as an environmental activist.

Over the years, the team has updated the system to accommodate specific requests from Harrell. He is now able to switch on a “privacy mode”—when active, any decoded text will be automatically deleted. He can also opt to use a “profanity filter” while he’s talking to his young daughter.

“We have been able to add on to the software side of the device … improving the accuracy and adding more bells and whistles to enable me to be more independent when using the device,” says Harrell. “We are making the road as we walk it, or roll it, so to speak.”

Nothing short of revolutionary

Vansteesel cautions that while the device is working well for Harrell, there’s no guarantee it will work as well, or as long, for other people with ALS. Over the last decade, she has worked with a woman with ALS who used a fully implanted device to communicate using “brain clicks”—cursor clicks made using brain activity. The woman used her BCI for seven years, but it stopped working toward the end of that period, apparently due to brain degeneration.

At any rate, not everyone with ALS will be willing to undergo invasive brain surgery, says Jane Huggins, who is developing noninvasive BCIs at the University of Michigan and was not involved in the trial. “Long-term, independent use with efficient and accurate communication is kind of the holy grail of BCI,” she says. “But we have been finding a consistent aversion to hospital stays among people with progressive conditions like ALS.”

Harrell, however, calls the device “nothing short of revolutionary.” “This has allowed me to keep working and earn money and insurance for my family. This is reconnecting me with friends and family who are too shy or too afraid to come over and not be able to understand me,” Harrell says. “With my seven-year-old daughter, I am able to create a bond that I wasn’t before able to forge. Now I can read to them and help them sharpen their own reading skills. By doing so, I am able to share the responsibility of parenting with my wife, who does so much caregiving for me and also our daughter.”

Stavisky and his colleagues hope to improve the device further still. “We’re never satisfied,” he says. One aim is to eventually restore Harrell’s “full voice.” They are working on a “brain-to-voice” system that could directly decode brain activity to a speaking voice, complete with natural-sounding cadence, inflection and intonation—a voice that could sound happy, angry, or sarcastic, for example.

“I was quietly confident that I could get some personal benefit from the system,” says Harrell. “Never in a million years would I think that I would achieve this much.” 

Earlier this week, Life Biosciences, a biotech company focused on reversing age-related diseases, announced that it had dosed its first volunteer. A person with glaucoma has had an experimental treatment injected straight into their eyeball.

The idea is to try to treat the disease—which can cause vision loss—by regenerating healthy nerves in the eye. But David Sinclair, the chairman and cofounder of the company behind the trial, hopes to go further. If the treatment can reverse glaucoma, perhaps similar treatments can reverse other diseases of aging. Maybe, just maybe, they can reverse aging altogether.

The approach is designed to work by “reprogramming” cells to a younger state. It’s one of many strategies being explored by biotech companies looking to slow and reverse the process of aging. But of all of them, it seems to be the one that is truly taking off.

Aging is complicated. As we get older, we experience so many changes across pretty much all our biological systems. Scientists have tried to categorize these effects. In 2013, one team published a seminal paper describing nine “hallmarks of aging.” That list features many of the processes scientists have attempted to target. But some of those targets have fallen in and out of fashion over the years.

Take telomere attrition, for example. Telomeres are DNA sequences at the ends of our chromosomes, often likened to the plastic caps that stop the ends of our shoelaces from fraying. When cells divide, telomeres shorten until, eventually, the DNA is vulnerable to damage.

When I started reporting on aging, telomere shortening was all the rage. Shrinking telomeres had been linked to age-related diseases of the heart and brain. Shortened telomeres were considered a sign of premature aging. In 2015 Liz Parrish, CEO of the biotech company BioViva, injected herself with an experimental gene therapy that she hoped might lengthen her telomeres.

Then it suddenly seemed to go out of style. Research continued, but all the excitement within the aging and longevity community seemed to move on to another hallmark. (Parrish also continued with self-experimentation; she calls herself “the most genetically modified person on Earth.”)

That hallmark was cellular senescence. This happens when cells stop dividing but don’t die, instead entering a “zombie” state in which they churn out chemicals that can cause harmful inflammation.

Senescent cells gradually accumulate in pretty much every organ studied, where they are thought to contribute to age-related damage. Why not just periodically clear them out? When a team of scientists took that approach in mice in 2011, they found they could delay the onset of age-related conditions like cataracts and hunchback. The treated mice even looked younger.

But when scientists at Unity Biotechnology trialed a similar approach in people with osteoarthritis and an age-related eye condition in the late 2010s and early 2020s, the results were disappointing. The company laid off every employee in May last year and has since shuttered entirely.

Again, that doesn’t mean senolytic drugs that target “zombie cells” won’t work. But it feels as if many in the field have moved on. These days, the buzz is all about reprogramming.

The idea here is to essentially return cells to a young state. It’s based on the Nobel Prize–winning discovery that four genetic factors can turn an adult cell into a stem cell, which can be encouraged to develop into pretty much any other cell type.

Some promising studies in mice suggest that this approach might help wind back the clock. It seems to improve tissue healing, restore vision, and even improve learning and memory.

Running parallel to all this research are repeated injections of hundreds of millions of dollars in funding. In 2021, my colleague Antonio Regalado reported on the founding of the biotech company Altos Labs to pursue reprogramming for rejuvenation.

Altos was funded by the billionaire Yuri Milner—reportedly along with Jeff Bezos, among others—to the tune of $3 billion, a previously unheard-of figure for a biotech startup. Other well-funded companies have since sprung up in this space.

There’s Retro Biosciences, for instance, which is pursuing reprogramming (among other approaches) in an effort to add 10 years of healthy life to human lifespans. Retro’s launch was supported by $180 million from OpenAI’s Sam Altman. Last month, the company announced a valuation of $1.8 billion.

NewLimit, another billionaire-backed biotech exploring reprogramming, says it has promising results from research in mice. It plans to trial a drug designed to rejuvenate the liver in people next year. Last week, the company announced it had raised $435 million toward reaching that goal, among others.

Life Biosciences, which was founded by the Harvard biologist David Sinclair, most recently secured $80 million to support its research. The eye trial is now officially underway, but Sinclair also has plans for whole-body rejuvenation. Earlier this week, he told my colleague Antonio that he plans to test a “highly, highly confidential” oral reprogramming drug as part of a $101 million competition organized by the XPrize Foundation. 

Reprogramming has certainly caught the attention of scientists, biotech companies, and investors. Studies in mice are hugely promising. Human trials are launching. And research in the field has billions of dollars’ worth of support.A lot of people in the field are really excited about reprogramming. But it comes with risks. And we still don’t know if it will work. The question now is: Do we finally have a rejuvenation drug within reach? And if not, what will the next research trend look like?

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

Correction: This article has been updated to reflect that Liz Parrish claimed to have undergone her first experimental gene therapy in 2015, not 2017.

This week I’ve been at SXSW London. There’s been music, film, and a lot—and I mean a lot—of talk about AI. I also had the opportunity to sit down with Gloria Mark, a psychologist at the University of California, Irvine, who has spent the last 30 years studying how people interact with digital technologies.

Early in her career, the biggest concerns were the potential impacts of internet and email use on our brains. We may laugh those concerns off today, but it’s true that as the technologies became more ubiquitous and ingrained in our daily lives, our attention spans began to shrink.

Mark is worried that things are only getting worse. The title of our session was “Have we lost control of our brains?” Unfortunately, Mark told me, the answer is yes.

Around two decades ago, Mark started wondering about how our use of devices might affect our attention spans. She set up what she calls “living laboratories,” using sensors and trackers to monitor adult volunteers’ attention, mood, and behavior when they were using devices.

In 2003, she found that the average user had an attention span of around two and a half minutes. That’s how long people could spend focused on one thing before moving on to something else. “That surprised me at the time,” she told me during our session on Wednesday. “I thought: Wow, this is really short.”

But when she repeated the experiment in 2012, she found that attention spans had shrunk—all the way down to around 75 seconds on average, she said. In research she conducted between 2014 and 2020, attention spans shrank further still—to a mere 47 seconds, on average. Yikes.

And it’s not good for us. Mark told me that she’s found switching our attention so frequently is stressful. “We would have people wear heart rate monitors, and … we would see direct correlation between switching attention fast and stress going up,” she told me.

All this distraction makes it harder for us to get stuff done, too. “It just takes longer to do any single task if you’re switching your attention,” she told me. “It’s not great for performance. It’s not great for our emotional well-being.”

And that’s for adults. What about the effects of digital technologies on children? A few months ago, Meta (which owns Facebook and Instagram) and Google’s YouTube were ordered to pay millions of dollars in damages to a 20-year-old woman who had accused the companies of creating products that led her to develop a childhood addiction.

Just a couple of weeks ago, Meta settled another lawsuit, this one brought by a rural school district in Kentucky. The district had also accused the company of designing addictive products that were harmful to students and had sought more than $60 million to cover the costs of their mental-health needs. Around 1,200 other school districts are taking similar legal action against social media companies.

But social media isn’t all bad, all the time. It can provide opportunities for some people, including those from marginalized groups, to form connections that might otherwise be difficult. A 2024 survey of LGBTQ+ teenagers found that while some described social media as a place of rejection and fear, others described it as a place where they felt a sense of belonging, where they could develop friendships and cultivate their identity.

In truth, we can’t definitively say what effects using social media is having on children across the board, says Mark. “There have been lots and lots of studies, and the evidence is to date inconclusive,” she told me. (Despite what you might read in best-selling books on the subject.)

Mark is hopeful that large, long-term studies might finally start shedding a bit more light on this question. An effort of this nature is underway in Australia, which enacted a social media ban for under-16s at the end of last year.

Given this uncertainty over a 20-year-old technology, I wondered if Mark had any thoughts on the potential impacts of AI—an obviously much newer offering that within the space of a couple of years appears to have become deeply integrated into our digital lives.

She told me she’s worried.

When we put in effort to do something—such as evaluating or summarizing content—we’re doing what’s known as “depth of processing,” she told me. “When you’re actively engaged with information, you’re processing it on a very deep level,” she said. “Then you’re more likely to learn it, to understand it, [and] to retain it.”

That’s not happening when most people use AI bots like ChatGPT, Claude, and Gemini. When we ask these tools to write, summarize, or evaluate for us, we’re no longer doing that depth of processing. “You’re deferring your cognitive work to AI,” she said. “And it’s not good for us.”

The risk is that our cognitive abilities will weaken over time. “If you’re not constantly exercising your muscles, they can atrophy,” Mark said. “And that’s exactly what can happen with our minds.” People with weaker critical thinking skills are more likely to fall prey to misinformation, she added.

Interactions with AI-powered “synthetic companions” can be just as harmful. Relationships between human beings take work—time, effort, and understanding. None of that is needed if you’re forming a relationship with a sycophantic bot. The “muscle” we risk atrophying here is emotional intelligence, which surveys suggest is already on the decline, said Mark.

She’s not painting a particularly rosy picture.

“If we continue on this trajectory, attention spans are diminished, loneliness is rising, boredom is rising, emotional intelligence decreasing, and actually our sense of purpose, according to studies, is also decreasing,” she said.

Luckily, she thinks we can course-correct by changing our relationship with these technologies. The key factor is effort.

The more effort we put into something, the deeper the satisfaction we stand to gain, Mark told me. That means making an effort to read a book rather than skimming its summary, and to meet with friends in person when you can. Try not to use GPS in places where you can probably manage without it.

“I love technology; we can’t give it up,” she told me. “[But] we have to learn how to create new life routines.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.

The alert was raised on May 5. Four health-care workers in the Ituri Province of the Democratic Republic of the Congo had died from an unknown illness within four days.

Rapid response teams were sent to investigate, and tests at a research center in Kinshasa revealed the culprit: the Bundibugyo virus, one of the viruses that cause Ebola. Suspected cases of the disease have snowballed in the last few weeks. By May 24, the WHO had estimated that 223 people had died from the disease. There were over 900 suspected cases. Today’s figures are likely to be higher.

A couple of weeks ago, I covered the hantavirus outbreak aboard a cruise ship. Three people sadly died, but the outbreak itself was kept under control. There have been no further deaths, and passengers have been safely repatriated. The picture for Ebola is far bleaker. And there are several reasons why.

The most obvious is the disease itself. Ebola is a severe disease with an average 50% fatality rate. Previous outbreaks have resulted in thousands of deaths. (Hantavirus also has a high fatality rate, but it doesn’t usually spread as easily between humans.) 

Between 2014 and 2016, an Ebola outbreak in West Africa caused more than 11,000 deaths. A more recent outbreak, which took place between 2018 and 2020, caused 2,299 deaths before being brought under control with a vaccination campaign.

But those outbreaks were caused by the Zaire virus, which has a different genetic sequence. There is no vaccine for the Bundibugyo virus. We don’t know if the two vaccines approved for Zaire might also work for Bundibugyo. There’s a concern they might even make things worse by interfering with a person’s immune response to the virus.  

Scientists are working on potential Bundibugyo vaccines. But the most advanced efforts are still months away from clinical trials. There are no specific antiviral treatments for the virus, either.

So to control the outbreak, health-care workers are trying to stop the spread of the disease. Ebolaviruses can be transmitted to humans by animals including fruit bats, chimpanzees, and gorillas. They can then spread between people via contact with bodily fluids such as blood or vomit.

That’s why the virus is often spread among family members, to health-care workers, and during some burial services. The WHO advises isolating people who have the virus in treatment centers. It also recommends safe burial measures that limit physical contact with the deceased, for example. Communities need to be informed about the virus and how it spreads, and health professionals should be on hand to diagnose cases and track them.

That’s all easier said than done in an era of misinformation. Some members of the community even doubt whether the disease is real. There have been three attacks on health-care facilities in the region in recent weeks.

Last week, two treatment centers were burned down. The first incident occurred after relatives of a deceased man were prohibited from retrieving his (infectious) body. As a result of the second incident, 18 suspected cases reentered the community.

A couple of days later, a group of men unleashed gunfire at Mongbwalu General Hospital, which was also treating people with Ebola. They were demanding the bodies of their deceased relatives.

There are more causes for concern when it comes to the spread of the virus. The Ebola outbreak is thought to have originated in Mongbwalu, a high-traffic mining hub. People who caught the virus in Mongbwalu are thought to have sought care in neighboring districts. And the wider province borders both South Sudan and Uganda. So far, Uganda has reported seven confirmed cases and one death. South Sudan’s health ministry has said it will strengthen surveillance, but no cases have been reported in the country so far. 

Violence in the region is making it much harder to contain the spread of the virus, too. Conflict involving multiple armed groups, including deadly attacks on civilians, has hampered humanitarian and health-care efforts. Poor infrastructure and damaged roads make matters even worse. Food insecurity is ravaging the region as well—this year, nearly 10 million people in the region face acute hunger.

Together, these factors are making it “nearly impossible” to isolate people with Ebola and trace others who have been in contact with them, WHO director general Tedros Adhanom Ghebreyesus said in a statement earlier this week.

The dismantling of US aid programs hasn’t helped either. US government funding for international health projects has steeply declined since the start of President Donald Trump’s second term. These cuts have harmed disease surveillance systems, according to the International Rescue Committee, a humanitarian nonprofit.

“Funding cuts have left the region dangerously exposed,” Heather Reoch Kerr, the organization’s country director for the Democratic Republic of the Congo, said in a statement. “Years of underinvestment and recent funding cuts have left many health facilities without adequate protective equipment, surveillance capacity, or frontline support needed to respond quickly and safely.”

The US has mobilized emergency funding for the outbreak, and a spokesperson for the State Department has argued that none of the administration’s actions have hampered the Ebola response. But health experts counter that the damage has already been done.

On May 17, the WHO declared the Ebola outbreak a public health emergency of international concern. In a statement on Wednesday, Tedros described the situation as “a catastrophic collision of disease and conflict with the Ebola outbreak in Ituri province outpacing the response.”In an online appeal to residents on Wednesday, ahead of an in-person visit, Tedros pleaded for a ceasefire and commended the spirit of community members. He also acknowledged the steep challenges they face. “You are already carrying so much: malaria, hunger, insecurity, and the daily struggle to keep your families safe,” he wrote in French. “And now Ebola. It’s not fair, and I won’t pretend otherwise.”

This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.