There are three ways to die: of injury, disease, or old age. Over time, humans have gotten better at avoiding the first two, but as we get older, senescence—the gradual deterioration of bodily functions with age—is inevitable. Some species seem to do better than others, though: Take the hydra, a tiny freshwater creature that some scientists have deemed potentially immortal. Last year, a naked mole rat made headlines for turning 39, five times the typical lifespan for similarly sized rodents. And just a few months ago, a giant Aldabra tortoise named Jonathan celebrated what was believed to be his 190th birthday, making him the world’s oldest living land animal.
Cases like these beg the question: Is it possible to escape aging?
The authors of a study published in Science last month say yes. Well, if you’re a turtle. With an extensive analysis of 52 species of turtles (a designation that includes both water dwellers and land-lodging tortoises), the team of four scientists found that the majority of them showed exceptionally slow—and in some cases, negligible—senescence while in captivity. That doesn’t make them immortal; turtles can still die from illness or injury. But unlike birds and mammals, their overall risk of death doesn’t increase with age. “We confirmed something that was suspected a long time ago, but never proven,” says Fernando Colchero, a biodemographer at the University of Southern Denmark.
Aging rate is a measure of how the risk of death increases among a population of organisms as they get older. For birds and mammals, that risk is thought to grow exponentially with age. But for most of the turtle species in the study, that rate was nearly flat, no matter how old they got.
Colchero and his colleagues also found that the environment the animals lived in plays a role. “Turtles and tortoises, based on comparing our results to those from animals in the wild, can actually change their aging rates dramatically when conditions improve,” he says, referring to factors like protection from predators, a controlled climate, and unlimited access to food and shelter. That’s distinct from previous work using primate data that reported increases in longevity due to better living conditions, but no significant reduction in mortality due to slowed aging.
What gives? Some evolutionary theories propose that senescence is the result of an energy trade-off. Most mammals and birds stop growing once they reach sexual maturity, Colchero says, at which point their energy gets prioritized for procreation, rather than cellular repair. Without sufficient upkeep to counter wear and tear, bodies become more vulnerable to chronic age-related conditions, as well as injuries or infections. “But many reptiles don’t. They keep growing, which means that they seem to be really efficient at repairing damages and keeping bodily functions working well,” he says.
According to Rita da Silva, a biologist who led the study with Colchero, animals with this quality are prime candidates for evading senescence. It’s an idea that’s been around since the 1990s, and to prove it, the researchers collected demographic information from the Zoological Information Management System, a database of records from zoos and aquariums maintained by the nonprofit organization Species360. They selected species that had data for at least 110 animals, and focused only on turtles living in fresh water or on land.
The Covid-19 pandemic is considered by many experts to be a mass disabling event. Though most people fully recover from a battle with the highly infectious coronavirus, a significant chunk of patients develop lingering, sometimes debilitating symptoms—aka long Covid. Estimates of how many Covid patients endure long-term symptoms vary considerably. But the US Centers for Disease Control and Prevention recently estimated that nearly one in five Covid patients report persistent symptoms. With hundreds of millions of Covid-19 cases reported around the globe, even the more modest estimates still suggest that tens of millions have lasting effects.
Yet, as those patients seek effective care, researchers are scrambling to define, understand, and treat this new phenomenon. Many patients have reported uphill battles for finding care and relief, including long waits at clinics and few treatment options when they see a care provider.
Cue the quacks. This situation is ripe for unscrupulous actors to step in and begin offering unproven products and treatments—likely at exorbitant prices. It’s a tried-and-true model: When modern medicine is not able to provide evidence-based treatment, quacks slither in to console the desperate, untreated patients. Amid their sympathetic platitudes, they rebuke modern medicine, scowl at callous physicians, and scoff at the slow pace and high price of clinical trials. With any ill-gotten trust they earn, these bad actors can peddle unproven treatments and false hope.
There are already reports in the US of such unproven long-Covid treatments, such as supplements, vitamins, infusions, fasts, ozone therapy, and off-label drug prescribing. But, a British investigation published this week highlights a growing international trend of pricey “blood washing” treatments.
The investigation, carried out by the British outlet ITV News and The BMJ, revealed that thousands of long-Covid patients are traveling to private clinics in various countries—including Switzerland, Germany, and Cyprus—to receive blood filtering, or apheresis, which is not proven to treat long Covid.
Apheresis is an established medical therapy, but it’s used to treat specific conditions by filtering out known problematic components of blood, such as filtering out LDL (low-density lipoprotein) in people with intractable high cholesterol, or removing malignant white blood cells in people with leukemia.
In the case of long-Covid patients, it seems apheresis treatments are used to remove a variety of things that may or may not be problematic. That includes LDL and inflammatory molecules, a strategy initially designed to treat people with cardiovascular disease. Internal medicine doctor Beate Jaeger, who runs the Lipid Center North Rhine in Germany and has started treating long-Covid patients, touts the method, which involves filtering blood through a heparin filter. She also prescribes long-Covid patients a cocktail of anticoagulant drugs.
Jaeger hypothesizes that the blood of people with long Covid is too viscous and contains small blood clots. She suggests that thinning the blood with drugs and apheresis can improve microcirculation and overall health. But there’s no evidence that this hypothesis is correct or that the treatment is effective. When Jaeger tried to publish her hypothesis in a German medical journal, it was rejected.
Robert Ariens, professor of vascular biology at the University of Leeds School of Medicine, told The BMJ and ITV that the treatment is premature. For one thing, researchers don’t understand how microclots form, if apheresis and anticoagulation drugs reduce them, and if a reduction would even matter for disease. “If we don’t know the mechanisms by which the microclots form and whether or not they are causative of disease, it seems premature to design a treatment to take the microclots away, as both apheresis and triple anticoagulation are not without risks, the obvious one being bleeding,” Ariens said.
Jaeger, meanwhile, defended treating patients despite a rejected hypothesis and a lack of evidence. She expressed anger over “dogmatism” in medicine and claimed to have treated patients in her clinic who arrived in wheelchairs but walked out. “If I see a child in a wheelchair suffering for a year, I prefer to treat and not to wait for 100 percent evidence,” she said.
And Jaeger isn’t alone; other clinics have also started offering apheresis for long Covid. The British investigation interviewed a woman in the Netherlands, Gitte Boumeester, who paid more than $60,000—nearly all her savings—for treatment at a new long-Covid clinic in Cyprus after seeing positive anecdotes online. The woman, desperate for relief from her long-Covid symptoms, signed a dubious consent form filled with spelling mistakes, grammatical errors, and half-finished sentences that waived her rights.
Daniel Sokol, a London barrister and medical ethicist, said the form would be invalid under English and Welsh law. “You can’t say, ‘By the way, you agree not to sue us if we cause you horrible injury or kill you, even if it’s through our own negligence,’” he told the investigators. “You can’t do that.”
At the Cyprus clinic, Boumeester received a battery of other unproven treatments along with the apheresis, including vitamin infusions, hyperbaric oxygen treatment, anticoagulants, and hydroxychloroquine, which is notoriously ineffective against Covid-19. After two months in Cyprus, subjecting herself to various treatments and draining her bank account, Boumeester said, she’d seen no improvement in her debilitating symptoms, which include heart palpitations, chest pain, shortness of breath, and brain fog.
“I do think they should emphasize the experimental nature of the treatments more, especially because it’s so expensive,” Boumeester said. “I realized before I started that the outcome was uncertain, but everyone at the clinic is so positive that you start to believe it too and get your hopes up.”
Since leptin is released by fat cells, scientists believe its presence in the blood is likely to signal to the brain that the animal is in an environment where food is ample and there’s no need to conserve energy. The new work suggests that low levels of leptin alert the brain to the malnourished state of the body, switching the brain into low-power mode.
“These results are unusually satisfying,” said Julia Harris, a neuroscientist at the Francis Crick Institute in London. “It is not so common to obtain such a beautiful finding that is so in line with the existing understanding,”
Distorting the Neuroscience?
A significant implication of the new findings is that much of what we know about how brains and neurons work may have been learned from brains that researchers unwittingly put into low-power mode. It is extremely common to restrict the amount of food available to mice and other experimental animals for weeks before and during neuroscience studies to motivate them to perform tasks in return for a food reward. (Otherwise, animals would often rather just sit around.)
“One really profound impact is that it clearly shows that food restriction does impact brain function,” said Rochefort. The observed changes in the flow of charged ions could be especially significant for learning and memory processes, she suggested, since they rely on specific changes happening at the synapses.
“We have to think really carefully about how we design experiments and how we interpret experiments if we want to ask questions about the sensitivity of an animal’s perception, or the sensitivity of neurons,” Glickfeld said.
The results also open up brand-new questions about how other physiological states and hormone signals could affect the brain, and whether differing levels of hormones in the bloodstream might cause individuals to see the world slightly differently.
Rune Nguyen Rasmussen, a neuroscientist at the University of Copenhagen, noted that people vary in their leptin and overall metabolic profiles. “Does that mean, then, that even our visual perception—although we might not be aware of it—is actually different between humans?” he said.
Rasmussen cautions that the question is provocative, with few solid hints to the answer. It seems likely that the conscious visual perceptions of the mice were affected by food deprivation because there were changes in the neuronal representations of those perceptions and in the animals’ behaviors. We can’t know for sure, however, “since this would require that the animals could describe to us their qualitative visual experience, and obviously they cannot do this,” he said.
But so far there also aren’t any reasons to think that the low-power mode enacted by the visual cortical neurons in mice, and its impact on perception, won’t be the same in humans and other mammals.
“These are mechanisms that I think are really fundamental to neurons,” Glickfeld said.
Editor’s note: Nathalie Rochefort is a member of the board of the Simons Initiative for the Developing Brain, which is funded by the Simons Foundation, the sponsor ofthis editorially independent magazine. Maria Geffen is a member of the advisory board for Quanta.
Original storyreprinted with permission from Quanta Magazine, an editorially independent publication of theSimons Foundationwhose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.
Historically, Shelta Cave was one of the most diverse cave systems in the eastern United States. Long before Niemiller and other scientists came along, beetles, salamanders, shrimp, crayfish, and other animals lived out their days in the dark. Often blind and lacking pigmentation, many cave-dwelling species live longer than their surface-dwelling relatives, thanks to slower metabolisms—a common evolutionary adaptation to subterranean life. For example, the red swamp crayfish, the unfortunate star of many a Louisiana crawfish boil, can live up to five years in the swamps and ditches they call home. Shelta’s southern cave crayfish, O. australis, lives up to 22 years, and it’s thought that the Shelta Cave crayfish has a similar lifespan.
A colony of gray bats also made Shelta Cave their home. Small enough to fit in the palm of your hand, these adorable, furry “microbats” deposited guano throughout the cave—a valuable food source for many of the other cave critters, including the Shelta Cave crayfish. For centuries, the balanced ecosystem of bats, crayfish, and other Shelta Cave animals carried on, undisturbed.
Then entrepreneur Henry M. Fuller came along. In 1888, Fuller bought the cave, naming it after his daughter, according to Scott Shaw, who manages the Shelta Cave Nature Preserve. A year later, Fuller built a wooden dance floor and installed some of the city’s first electric lights in the cavern, creating a popular entertainment destination. When rainwater swelled the subterranean lakes, Fuller even operated wooden boat tours for visitors. Nicknaming the cave “the eighth wonder of the world,” Fuller ran ads that boasted, “all the discoveries of the old world pale into insignificance in comparison to this greatest sight on earth or under the earth.” “Yeah, it was a big affair,” says Shaw—but it was not meant to last.
After 1896, Shelta changed hands several times, reportedly even becoming a speakeasy during Prohibition. In 1967, the National Speleological Society (NSS), an organization that studies and protects caves, bought the cave to preserve its unique ecosystem.
Last month, government officials met in Washington, DC, for the first Monarch Butterfly Summit, just as the milkweed in the “Monarch Waystations” that are now ubiquitous across American lawns began to bloom. Like everyone, they were worried about the iconic insect’s fate, following decades of notable population decline in the butterfly’s winter colonies.
There are two distinct (but genetically identical) populations of monarchs in the United States, and both are migratory. Monarchs west of the Rocky Mountains spend their winters in Southern California, while those east of the range fly thousands of miles from as far north as Ontario to central Mexico, where they wait out the cold months in stands of oyamel fir trees. Since the mid-90’s, scientists have found that the number of butterflies that make it to Mexico has fallen by about 70 percent. They blame bad weather, deforestation, and automobile collisions for the decline.
In 2020 alone, 26 percent fewer eastern monarchs made it to Mexico than the year before, having been waylaid by storm and drought. Those that survived the journey found their already-tiny wintering grounds reduced by illegal logging. In 2019, researchers concluded that the western monarch was “hovering at its quasi-extinction threshold” after a 97 percent reduction in that subpopulation since the 1980s.
So it may be surprising—and perhaps controversial—that a recent study published in the journal Global Change Biology suggests that some populations of monarch butterflies are actually on the rise. “There is no monarch butterfly apocalypse,” says Andrew Davis, an ecology professor at the University of Georgia (UGA) and coauthor of the study. “Not in the United States, anyway.”
His group’s work is unusual because it focuses on the insects’ breeding grounds, not their migratory stopovers. In other words, the team looked at counts taken in the summer throughout the US, not in the winter in Mexico or Southern California. Davis and his fellow researchers relied on more than 135,000 monarch observations made on both sides of the Rockies between 1993 and 2018 during the North American Butterfly Association’s (NABA) annual count. These events call on citizen scientists to record all the butterflies they see in a 15-mile radius over two days in early July.
While the research team noted that there have been slight declines in some regions of the US, particularly the Midwest and New England, areas like the Southeast and Pacific Northwest are seeing more monarchs. Taken together, the data suggests an overall annual increase of 1.36 percent across the species’ summer range, meaning that over the 25-year period, the summer population of monarchs in the US has increased by about 35 percent.
Davis says his team’s findings demonstrate that the butterflies’ breeding in summer is making up for the losses the insects experience during winter. “They’re able to rebound and repopulate their entire breeding range every year, regardless of how many are at the winter colonies,” he says. “It’s just mathematics. A single female can lay 500 eggs. If the conditions are right, the population explodes.”