Rochelle "Shelley" Buffenstein has one of the world's largest, if not the largest, lab-dwelling colonies of the naked mole rat. (No one has done a worldwide tabulation, but she has 4,500 of them.) Buffenstein has spent decades studying the little subterranean-dwelling rodents. Over the years, she and her colleagues have uncovered one surprising discovery after another, which has led them to re-orient the whole field of anti-aging research.
Naked mole rats defy everything we thought we knew about aging. These strange little rodents from arid regions of Africa, such as Kenya, Ethiopia and Somalia, live up to ten times longer than their size would suggest. And unlike virtually every other animal, they don't lose physical or cognitive abilities with age, and even retain their fertility up until the end of life. They appear to have active defenses against the ravages of time, suggesting that aging may not be inevitable. Could these unusual creatures teach humans how to extend life and ameliorate aging?
Buffenstein, who is senior principle investigator at Calico Life Sciences, has dedicated her life to finding out. Her early interest in the animals of what is now Zimbabwe led to her current position as a cutting-edge anti-aging researcher at Calico, the Google-funded health venture launched in 2013. The notoriously secretive company is focused on untangling the mysteries of why animals and people age, and whether there are ways to slow or temporarily arrest the process.
The small, wrinkly animal, which lives in underground burrows in the hot, arid regions of Africa, is hardly the beauty queen of the mammalian kingdom. Furless, buck-toothed and tiny-eyed, the creatures look like they could use a good orthodontist, a protective suit of clothes and possibly, some spectacles to enhance their eyesight. But these rats more than make up for their unimpressive looks with their superlative ability to adapt to some of the most inhospitable conditions on earth.
Based on the usual rule that body size predicts lifespan, naked mole rats shouldn't live that long. After all, similarly-sized rodents like mice have a life expectancy of two years or less. But Buffenstein was one of the first scientists to recognize that naked mole rats live an extraordinarily long time, with her oldest animal approaching 39 years of age. In addition, they never become geriatric in the human sense, defying the common signs of aging — age-related diseases, cognitive decline and even menopause. In fact, the queens, or females that do all the breeding in a bee-like underground colony, remain fertile and give birth to healthy pups up until what would be considered very old age in humans. And the naked mole rat has other curious abilities, such as the ability to endure extreme low-oxygen, or hypoxic, conditions like those they encounter in their underground nests.
"One thing we've learned from these animals is that they stay healthy until the very end."
It's not that the naked mole rat isn't subject to the vicissitudes of life, or the normal wear and tear of biological processes. Over the years, Buffenstein and her colleagues have discovered that, while the process of oxidative stress — thought for 50 years to be the main cause of aging — occurs in the naked mole rat just as in any other animal, its damage does not accumulate with age. Oxidative stress occurs during normal cell metabolism when oxygen "free radicals" with one or more unpaired electrons wreak havoc on large cellular molecules, leaving microscopic debris in their wake that clogs up the gears of healthy cell function. Somehow, naked mole rats have an enhanced ability to clear out the damaged cells and molecules before they can set off the usual chain reaction of cell dysfunction and death, according to a 2013 paper in which Buffenstein is the lead author.
Oxidative stress is not the only factor known to be problematic in aging. Slowly accumulating damage to DNA typically leads to protein malfunction and improper folding. In humans and most other animals, these protein fragments can accumulate in cells and gum up the works. Only not so much in naked mole rats, which are able to maintain normal protein folding throughout their long life. After years of discoveries like these, Buffenstein has gradually reframed her focus from "what goes wrong to produce aging?" to "what goes right in the naked mole rat to help it defy the normal wear and tear of life?" Buffenstein's research suggests that the tiny mammals have a unique ability to somehow clear out damaged protein fragments and other toxic debris before they can cause disease and aging.
How She Got Here
Buffenstein ascribes her initial acquaintance with the naked mole rat to serendipity. Back in 1979, her postgraduate mentor Jenny Jarvis at the University of Cape Town in South Africa kept a small colony of rats in her office while studying the mechanisms that lead to the animals' unusual adaptive capabilities. It was Buffenstein's job to take care of them. Working with Jarvis, Buffenstein focused on understanding their unique adaptations to the extreme conditions of their natural habitat.
They studied the unusual behaviors regulating the rat colonies. For instance, they observed that designated "workers" dig the entire colony's underground tunnels and a single reproducing female breeds with only a small number of males. Buffenstein also examined how these animals are able to survive without the "sunshine hormone" — vitamin D — and their unusual modes of regulating their internal temperatures and converting food into energy. Though classified as mammals, the rodents simply don't conform to the mammalian handbook, having found ingenuous ways to alter their bodies and behavior that is fine-tuned to the scorching heat and aridity of their environment.
To escape the heat, they simply burrow underground and live in elaborate tunnels. To cope with the low-oxygen conditions underground, they slowed their metabolism and learned to live for extended periods of time in such hypoxic conditions that an ordinary animal would quickly suffocate. But it was slowly dawning on Buffenstein that the small creatures were exceptional in additional ways.
When Buffenstein got her first academic position at the University of Witwatersrand in Johannesburg, Jarvis said she could take some of the naked mole rats with her. When she did, Buffenstein noticed that the animals were living far longer than similarly sized rodents. "At that stage, they were about ten years old. Little did I know how long they would eventually show us they could live," she says.
In 1997, after accepting a position at the City College of New York, Buffenstein moved to the U.S. and took her rat colony with her. There she was able to pursue an evolving narrative about the humble naked mole rat that continued to defy expectations. As the years passed, it was becoming more and more evident that her observations could have major implications for aging research. Eventually, she took a position at the Barshop Institute for Aging and Longevity Studies in San Antonio, Texas.
One early observation of Buffenstein's suggested that the species most often used in aging research—mice, roundworms, fruit flies and yeast—have short lifespans and poor defenses against aging. These animals provide important insights into how aging works, and have revealed possible targets for intervention. But they don't show what goes right in apparently non-aging animals like the naked mole rat.
Buffenstein's years of studying the rats has laid the foundation for a whole new perspective in aging research.
"My hypothesis," she says, "is that naked mole rats are very good at removing damaged macromolecules and cells, thereby maintaining homeostasis and cell and tissue function. All the repair pathways examined by us and others in the field point to more efficient repair and more rapid responses to damaging agents." These include things like free radicals and radiation.
Some researchers today are building on Buffenstein's foundational discoveries to home in on possible anti-aging mechanisms that lead to the extraordinary resilience of naked mole rats. University of Cambridge researcher and co-founder of the institution's Naked Mole-Rat Initiative, Ewan St. John Smith, is studying the animal's resistance to cancer.
In a 2020 paper published in Nature, Smith and his colleagues established that naked mole rats harbor cancer-causing genes, and these genes occasionally create cancer cells. But something in the rats shuts the multiplication process down before the cells can grow out of control and form tumors. Now, scientists want to know what mechanisms, exactly, are at play in preventing the cells from invading healthy tissues. Smith has hypothesized that the answer is somehow embedded in interactions in the cells' microenvironment.
He also thinks the animal's immune system could just be very effective at seeking out and destroying cancer cells. Several current cancer therapies work by boosting the body's immune system so it can attack and eliminate the toxic cells. It's possible that the naked mole rat's immune system naturally goes into hyper-drive when cancer cells appear, enabling it to nip the disease in the bud before tumors can form. A pharmacologist by training, Smith thinks that if there is some chemical mediator in the naked mole rat that supercharges its immune cells, perhaps that mediator can be synthesized in a drug to treat humans for cancer.
The naked mole rat's extreme tolerance to hypoxia could also play a role. "Interestingly," he says, "when cells become cancerous, they also become hypoxic, and naked mole rats are known to be very resistant to hypoxia.
He notes that a form of low-level hypoxia is also present in the bodies and brains of both aged mice and older humans. It's commonly seen in the brains of humans with Alzheimer's disease and other forms of age-related dementia. This suggests that hypoxia in humans — and in other mammals — may have a role to play in Alzheimer's and the aging process itself. Resistance to hypoxia could be why the naked mole rat, in Smith's words, "chugs along quite happily" in conditions that in humans are associated with disease and decline.
Smith cheerfully acknowledges his debt to Buffenstein for laying so much of the groundwork in a field rife with possible implications for anti-aging. "Shelley is amazing," he says. "Naked mole rats have a queen and I always refer to her as the queen of the naked mole rat world." In fact, Buffenstein gave Smith his first colony of rats, which he's since grown to about 150. "Some of them will still be around when I retire," he jokes.
Vera Gorbunova, a professor of biology and oncology at the University of Rochester who studies both longevity and cancer in naked mole rats, credits Buffenstein with getting others to study the animals for anti-aging purposes. Gorbunova believes that "cancer and aging go hand-in-hand" and that longer-lived animals have better, more accurate DNA repair.
Gorbunova is especially interested in the naked mole rat's ability to secrete a superabundance of a "super-sugar" molecule called hyaluronan, a ubiquitous additive to skin creams for its moisturizing effect. Gorbunova and others have observed that the presence of high concentrations of hyaluronan in the naked mole rat's extracellular matrix — the chemical-rich solution between cells — prevents the overcrowding of cells. This, perhaps, could be the key to the animal's ability to stop tumors from forming.
Hyaluronan is also present in the extracellular matrix of humans, but the naked mole rat molecule is more than five times larger than the versions found in humans or mice, and is thought to play a significant part in the animal's DNA repair. But just rubbing a cream containing hyaluronan over your skin won't stop cancer or aging. High concentrations of the substance in the extracellular matrix throughout your body would likely be needed.
Gorbunova notes that the naked mole rat offers a multitude of possibilities that could eventually lead to drugs to slow human aging. "I'm optimistic that there are many different strategies, because the naked mole rat likely has many processes going on that fight aging," she says. "I think that in a relatively short time, there will be bonafide treatments to test in animals. One thing we've learned from these animals is that they stay healthy until the very end."
So if naked mole rats don't become frail with age or develop age-related diseases, what does kill them? The answer, unfortunately, is usually other naked mole rats. Buffenstein has long noted that even though they live in highly cooperative colonies, they can be quite cantankerous when there's a disruption in the hierarchy, a sentiment echoed by Gorbunova. "Sometimes there are periods of peace and quiet, but if something happens to the queen, all hell breaks loose," she says. "If the queen is strong, everybody knows their place," but if the queen dies, the new queen is inevitably decided by violent competition.
To the casual observer, a strange, wrinkly rodent like the naked mole rat might seem to have little to teach us about ourselves, but Buffenstein is confident that her discoveries could have major implications for human longevity research. Today, at Calico's labs in San Francisco, she's focused entirely on the determining how anti-aging defense mechanisms in the rats could lead to similar defenses being stimulated or introduced in humans.
"The million-dollar question is, what are the mechanisms protecting against aging, and can these be translated into therapies to delay or abrogate human aging, too?"
Buffenstein fired up a new generation of scientists with multiple discoveries, especially the fundamental one that naked mole rats are subject to the same wear and tear over time as the rest of us, but somehow manage to reverse it. These days, the trailblazer is at work on untangling the molecular mechanisms involved in the animal's resistance to cardiac aging. On top of everything else, the small creature has a unique ability to fight off the scourge of heart disease, which is the leading cause of death in the industrialized world.
After all, the point is not to extend old age, but to slow down aging itself so that frailty and disability are compressed into a brief period after a long-extended period of vitality. By switching the focus from what goes wrong to mechanisms that defend against aging in the first place, the discoveries of Buffenstein and a new generation of researchers who are building on her groundbreaking research promise to be a driving force in the quest to extend not only life, but healthy, vigorous life in humans.
Jessica Ware is obsessed with bugs.
My guest today is a leading researcher on insects, the president of the Entomological Society of America and a curator at the American Museum of Natural History. Learn more about her here.
You may not think that insects and human health go hand-in-hand, but as Jessica makes clear, they’re closely related. A lot of people care about their health, and the health of other creatures on the planet, and the health of the planet itself, but researchers like Jessica are studying another thing we should be focusing on even more: how these seemingly separate areas are deeply entwined. (This is the theme of an upcoming event hosted by Leaps.org and the Aspen Institute.)
Listen to the Episode
Entomologist Jessica Ware
D. Finnin / AMNH
Maybe it feels like a core human instinct to demonize bugs as gross. We seem to try to eradicate them in every way possible, whether that’s with poison, or getting out our blood thirst by stomping them whenever they creep and crawl into sight.
But where did our fear of bugs really come from? Jessica makes a compelling case that a lot of it is cultural, rather than in-born, and we should be following the lead of other cultures that have learned to live with and appreciate bugs.
The truth is that a healthy planet depends on insects. You may feel stung by that news if you hate bugs. Reality bites.
Jessica and I talk about whether learning to live with insects should include eating them and gene editing them so they don’t transmit viruses. She also tells me about her important research into using genomic tools to track bugs in the wild to figure out why and how we’ve lost 50 percent of the insect population since 1970 according to some estimates – bad news because the ecosystems that make up the planet heavily depend on insects. Jessica is leading the way to better understand what’s causing these declines in order to start reversing these trends to save the insects and to save ourselves.
The first thing Jeroen Perk saw after he partially regained his sight nearly a decade ago was the outline of his guide dog Pedro.
“There was a white floor, and the dog was black,” recalls Perk, a 43-year-old investigator for the Dutch customs service. “I was crying. It was a very nice moment.”
Perk was diagnosed with retinitis pigmentosa as a child and had been blind since early adulthood. He has been able to use the implant placed into his retina in 2013 to help identify street crossings, and even ski and pursue archery. A video posted by the company that designed and manufactured the device indicates he’s a good shot.
Less black-and-white has been the journey Perk and others have been on after they were implanted with the Argus II, a second-generation device created by a Los Angeles-based company called Second Sight Medical Devices.
The Argus II uses the implant and a video camera embedded in a special pair of glasses to provide limited vision to those with retinitis pigmentosa, a genetic disease that causes cells in the retina to deteriorate. The camera feeds information to the implant, which sends electrical impulses into the retina to recapitulate what the camera sees. The impulses appear in the Argus II as a 60-pixel grid of blacks, grays and whites in the user’s eye that can render rough outlines of objects and their motion.
Smartphone and computer manufacturers typically stop issuing software upgrades to their devices after two or three years, eventually rendering them bricks. But is the smartphone approach acceptable for a device that helps restore the most crucial sense a human being possesses?
Ross Doerr, a retired disability rights attorney in Maine who received an Argus II in 2019, describes the field of vision as the equivalent of an index card held at arm’s length. Perk often brings objects close to his face to decipher them. Moreover, users must swivel their heads to take in visual data; moving their eyeballs does not work.
Despite its limitations, the Argus II beats the alternative. Perk no longer relies on his guide dog. Doerr was uplifted when he was able to see the outlines of Christmas trees at a holiday show.
“The fairy godmother department sort of reaches out and taps you on the shoulder once in a while,” Doerr says of his implant, which came about purely by chance. A surgeon treating his cataracts was partnered with the son of another surgeon who was implanting the devices, and he was referred.
Doerr had no reason to believe the shower of fairy dust wouldn’t continue. Second Sight held out promises that the Argus II recipients’ vision would gradually improve through upgrades to much higher pixel densities. The ability to recognize individual faces was even touted as a possibility. In the winter of 2020, Doerr was preparing to travel across the U.S. to Second Sight’s headquarters to receive an upgrade. But then COVID-19 descended, and the trip was canceled.
The pandemic also hit Second Sight’s bottom line. Doerr found out about its tribulations only from one of the company’s vision therapists, who told him the entire department was being laid off. Second Sight cut nearly 80% of its workforce in March 2020 and announced it would wind down operations.
Ross Doerr has mostly stopped using his Argus II, the result of combination of fear of losing its assistance from wear and tear and disdain for the company that brought it to market.
Second Sight’s implosion left some 350 Argus recipients in the metaphorical dark about what to do if their implants failed. Skeleton staff seem to have rarely responded to queries from their customers, at least based on the experiences of Perk and Doerr. And some recipients have unfortunately returned to the actual dark as well, as reports have surfaced of Argus II failures due to aging or worn-down parts.
Product support for complex products is remarkably uneven. Although the iconic Ford Mustang ceased production in the late 1960s, its parts market is so robust that it’s theoretically possible to assemble a new vehicle from recently crafted components. Conversely, smartphone and computer manufacturers typically stop issuing software upgrades to their devices after two or three years, eventually rendering them bricks. Consumers have accepted both extremes.
But is the smartphone approach acceptable for a device that helps restore the most crucial sense a human being possesses?
Margaret McLean, a senior fellow at the Markkula Center for Applied Ethics at Santa Clara University in California, notes companies like Second Sight have a greater obligation for product support than other consumer product ventures.
“In this particular case, you have a great deal of risk that is involved in using this device, the implant, and the after care of this device,” she says. “You cannot, like with your car, decide that ‘I don’t like my Mustang anymore,’ and go out and buy a Corvette.”
And, whether the Argus II implant works or not, its physical presence can impact critical medical decisions. Doerr’s doctor wanted him to undergo an MRI to assist in diagnosing attacks of vertigo. But the physician was concerned his implant might interfere. With the latest available manufacturer advisories on his implant nearly a decade old, the procedure was held up. Doerr spent months importuning Second Sight through phone calls, emails and Facebook postings to learn if his implant was contraindicated with MRIs, which he never received. Although the cause of his vertigo was found without an MRI, Doerr was hardly assured.
“Put that into context for a minute. I get into a serious car accident. I end up in the emergency room, and I have a tag saying I have an implanted medical device,” he says. “You can’t do an MRI until you get the proper information from the company. Who’s going to answer the phone?”
Second Sight’s management did answer the call to revamp its business. It netted nearly $78 million through a private stock placement and an initial public offering last year. At the end of 2021, Second Sight had nearly $70 million in cash on hand, according to a recent filing with the Securities and Exchange Commission.
And while the Argus II is still touted at length on Second Sight’s home page, it appears little of its corporate coffers are earmarked toward its support. These days, the company is focused on obtaining federal approvals for Orion, a new implant that would go directly into the recipient’s brain and could be used to remedy blindness from a variety of causes. It obtained a $6.4 million grant from the National Institutes of Health in May 2021 to help develop Orion.
Presented with a list of written questions by email, Second Sight’s spokesperson, Dave Gentry of the investor relations firm Red Chip Companies, copied a subordinate with an abrupt message to “please handle.” That was the only response from a company representative. A call to Second Sight acting chief executive officer Scott Dunbar went unreturned.
Whether or not the Orion succeeds remains to be seen. The company’s SEC filings suggest a viable and FDA-approved device is years away, and that operational losses are expected for the “foreseeable future.” Second Sight reported zero revenue in 2020 or 2021.
Moreover, the experiences of the Argus II recipients could color the reception of future Second Sight products. Doerr notes that his insurer paid nearly $500,000 to implant his device and for training on how to use it.
“What’s the insurance industry going to say the next time this crops up?” Doerr asks, noting that the company’s reputation is “completely shot” with the recipients of its implants.
Perk, who made speeches to praise the Argus II and is still featured in a video on the Second Sight website, says he also no longer supports the company.
Jeroen Perk, an investigator for the Dutch customs service, cried for joy after partially regaining his sight, but he no longer trusts Second Sight, the company that provided his implant.
Nevertheless, Perk remains highly reliant on the technology. When he dropped an external component of his device in late 2020 and it broke, Perk briefly debated whether to remain blind or find a way to get his Argus II working again. Three months later, he was able to revive it by crowdsourcing parts, primarily from surgeons with spare components or other Argus II recipients who no longer use their devices. Perk now has several spare parts in reserve in case of future breakdowns.
Despite the frantic efforts to retain what little sight he has, Perk has no regrets about having the device implanted. And while he no longer trusts Second Sight, he is looking forward to possibly obtaining more advanced implants from companies in the Netherlands and Australia working on their own products.
Doerr suggests that biotech firms whose implants are distributed globally be bound to some sort of international treaty requiring them to service their products in perpetuity. Such treaties are still applied to the salvage rights for ships that sunk centuries ago, he notes.
“I think that in a global tech economy, that would be a good thing,” says McLean, the fellow at Santa Clara, “but I am not optimistic about it in the near term. Business incentives push toward return on share to stockholders, not to patients and other stakeholders. We likely need to rely on some combination of corporately responsibility…and [international] government regulation. It’s tough—the Paris Climate Accord implementation at a slow walk comes to mind.”
Unlike Perk, Doerr has mostly stopped using his Argus II, the result of combination of fear of losing its assistance from wear and tear and disdain for the company that brought it to market. At 70, Doerr says he does not have the time or energy to hold the company more accountable. And with Second Sight having gone through a considerable corporate reorganization, Doerr believes a lawsuit to compel it to better serve its Argus recipients would be nothing but an extremely costly longshot.
“It’s corporate America at its best,” he observes.