Based on recent research, new therapies could promote a mix of viruses in the intestines to help prevent diseases of aging.
The microbiota and aging
In the early 1970s, scientists discovered that the composition of our gut microbiota changes as we age. Recent studies have found that the changes are remarkably predictable and follow a pattern: The microbiota undergoes rapid, dramatic changes as toddlers transition to solid foods; further changes become less dramatic during childhood as the microbiota strikes a balance between the host and the environment; and as that balance is achieved, the microbiota remains mostly stable during our adult years (ages 18-60). However, that stability is lost as we enter our elderly years, and the microbiome undergoes dramatic reorganization. This discovery led scientists to question what causes this change and what effect it has on health.
Centenarians have a distinct gut community enriched in microorganisms that synthesize potent antimicrobial molecules that can kill multidrug-resistant pathogens.
“We are always eager to find out why some people live extremely long lives. Previous research has shown that the intestinal bacteria of old Japanese citizens produce brand-new molecules that make them resistant to pathogenic — that is, disease-promoting — microorganisms. And if their intestines are better protected against infection, well, then that is probably one of the things that cause them to live longer than others,” said Joachim Johansen, a researcher at the University of Copenhagen.
In 2021, a team of Japanese scientists set out to characterize the effect of this change on older people’s health. They specifically wanted to determine if people who lived to be over 100 years old — that is, centenarians — underwent changes that provided them with unique benefits. They discovered centenarians have a distinct gut community enriched in microorganisms that synthesize potent antimicrobial molecules that can kill multidrug-resistant pathogens, including Clostridioides difficile and Enterococcus faecium. In other words, the late-life shift in microbiota reduces an older person’s susceptibility to common gut pathogens.
Viruses can change alter the genes of bacteria
Although the late-in-life microbiota change could be beneficial to health, it remained unclear what facilitated this shift. To solve this mystery, Johansen and his colleagues turned their attention to an often overlooked member of the microbiome: viruses. “Our intestines contain billions of viruses living inside bacteria, and they could not care less about human cells; instead, they infect the bacterial cells. And seeing as there are hundreds of different types of bacteria in our intestines, there are also lots of bacterial viruses,” said Simon Rasmussen, Johansen’s research advisor.
Centenarians had a more diverse virome, including previously undescribed viral genera.
For decades, scientists have explored the possibility of phage therapy — that is, using viruses that infect bacteria (called bacteriophages or simply phages) to kill pathogens. However, bacteriophages can also enhance the bacteria they infect. For example, they can provide genes that help their bacterial host attack other bacteria or provide new metabolic capabilities. Both of these can change which bacteria colonize the gut and, in turn, protect against certain disease states.
Intestinal viruses give bacteria new abilities
Johansen and his colleagues were interested in what types of viruses centenarians had in their gut and whether those viruses carried genes that altered metabolism. They compared fecal samples of healthy centenarians (100+ year-olds) with samples from younger patients (18-100 year-olds). They found that the centenarians had a more diverse virome, including previously undescribed viral genera.
They also revealed an enrichment of genes supporting key steps in the sulfate metabolic pathway. The authors speculate that this translates to increased levels of microbially derived sulfide, which may lead to health-promoting outcomes, such as supporting mucosal integrity and resistance to potential pathogens.
“We have learned that if a virus pays a bacterium a visit, it may actually strengthen the bacterium. The viruses we found in the healthy Japanese centenarians contained extra genes that could boost the bacteria,” said Johansen.
Simon Rasmussen added, “If you discover bacteria and viruses that have a positive effect on the human intestinal flora, the obvious next step is to find out whether only some or all of us have them. If we are able to get these bacteria and their viruses to move in with the people who do not have them, more people could benefit from them.”
This article originally appeared on Big Think, home of the brightest minds and biggest ideas of all time.
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Sonja Bauman, 39, and Mariela Florez, 83, taking one of their regular walks in Plantation, Fla. The pair met through an online platform called Papa that provides "family on demand." (Photo by Sonja Bauman)
In 2020, Papa connected Bauman, the 39-year-old Floridian, with another woman in her mid-70s who lives alone and has very limited mobility. Bauman began driving her to doctor’s appointments and helping her with chores around the house. “When I’m not there, she doesn’t leave her apartment,” said Bauman. The two have gone to the gym together, and they walk slowly through the neighborhood, chatting so it feels less like exercise.
Parker was driven to start Papa by the problem of social isolation among seniors, exacerbated by the pandemic, but he believes users of all ages can benefit. “Many of our Pals feel more comfortable opening up with older members than their same-aged friends,” he said.
Other platforms aim for similar, in-person connections. Generation Tech unites teens with seniors for technology training. And Mon Ami, which provides case management software for aging and disability service providers, has an app that connects isolated older people with college-age volunteers.
Making new connections through video
Several new sites match you with strangers for real-time video chatting on various topics, such as finding common ground on political issues. Other video platforms focus on intergenerational connections.
S. Jay Olshansky, a gerontology professor at the University of Illinois-Chicago, recalls the first time he saw Hyunseung Lee, an 11-year-old from Seoul, through his computer screen. The kid was shy, but Olshansky, 67, encouraged him to ask questions. “Turns out, he was thirsting for this kind of interaction.”
They’d connected through Eldera, a platform that pairs mentors age 60 and up with mentees, using an algorithm, for video conversations. “The time and wisdom of older adults is the most important natural resource we can give future generations,” said Dana Griffin, Eldera's CEO. “Connecting through a screen is the opposite of social media.”
In weekly meetings, Olshansky noticed Lee’s unique interest in math. “There’s something special in you,” Olshansky told him. “How do we bring it to the surface?” He suggested Lee write a book on his favorite subject, and the preteen ran with it, cranking out 70 pages in two weeks. Lee has published his love letter to theorems on Amazon.
Hyunseung Lee, age 11, of Korea, and U.S. college professor Jay Olshanksy, 67, discuss math, strategy and Hyunsung's budding career as a book author during their video chats through a platform called Eldera. (Photo by Dana Palmer/Eldera)
Lee’s parents told Olshansky that their son has become more assertive — a recurring theme, Griffin said. “Confidence is the number one thing parents tell us about.” Since Eldera’s inception last year, the number of mentors has grown exponentially. Even so, Griffin said the waitlist for mentors typically numbers 200 kids.
Another site, Big and Mini, hosts video interactions between seniors and young adults; about 10,000 active users have joined since 2019, said co-founder Aditi Merchant.
Users often bring the benefits of their video interactions to their real-world relationships. Olshansky views Lee as an older version of his grandkids. “Eldera teaches me how to interact with them.” Lee, high on confidence, began instructing his classmates in math. Griffin noted that a group of Eldera mentors in Memphis, who met initially on Eldera, now take walks together in-person to trade ideas for helping each other’s Eldera kids solve problems in their schools and communities.
“We’ve evolved into a community for older adults who want to give back to the world,” said Griffin. Other new tools for connection take the form of virtual reality apps.
Connecting in virtual reality
During pandemic isolation, record numbers of people bought devices for virtual and augmented reality. Such gadgets can convince you that you’re hanging out with friends, even if they’re in another hemisphere. Lifelike simulations from miles away could be especially useful for meaningful interactions between people of different generations, since they’re often geographically segregated.
VR’s benefits require further study, but users report less social isolation and depression, according to MIT research. The immersive, 3-D experience is more compelling than FaceTime or Zoom. “It’s like the difference between a phone call and video call,” said Rick Robinson, Vice President of AARP’s Innovation Labs.
“When VR is designed right, the medium disappears,” said Jeremy Bailenson of Stanford.
Dana Pierce, a 56-year-old government employee in Indiana, got Meta's VR headset in May, 2021, thinking she’d enjoy it more than a new laptop. After many virtual group tours of exotic destinations, she has no regrets. Her adventures occur on Alcove, an app made by Robinson’s Innovation Labs. He co-created it with VR-company Rendever and sought input from people over age 50 to tailor it to their interests. “I’m an introvert,” said Pierce. “I’ve been more socially active since getting my headset than I am in real life.”
Tagging along with her to places like Paris are avatars representing real people around the world. She’s gotten to know VR users in their 70s, 80s and 90s, as well as younger people and some her own age. One is a new friend she plays chess with in relaxing nature settings. Another is her oldest son. He lives 90 minutes away but, earlier this year, Pierce welcomed him and his girlfriend to her virtual house on Alcove. They chatted in the living room decorated with family photos uploaded by Pierce. Then they took out a boat to go VR fishing — because why not — until 2 a.m.
“When VR is designed right, the medium disappears,” said Jeremy Bailenson, a communications professor who directs Stanford’s Virtual Human Interaction Lab. He’s teaching a class of 175 students entirely in VR. After months of covid isolation, the first time the class met, “there was a big catharsis. It really feels like you’re in a big crowd.” Like-minded people meet in VR for events such as comedy shows and creative writing meetups, while the Swedish pop group ABBA has performed this year as digital versions of themselves (“ABBA-tars”) during a virtual concert tour.
Karen Fingerman, a psychologist and director of the Texas Aging and Longevity Center at the University of Texas-Austin, supports the idea of VR for social connection, though she added that some people need it more than others. Hospitals and assisted-living facilities are using products such as Penumbra’s REAL I-Series and MyndVR to bring VR excursions to isolated patients and seniors. “If you’re in a bed or facility, this gives you something to talk about,” said Gita Barry, Penumbra’s executive vice president.
Pierce uses it on most days. She may see another adult son, who lives with her, less often as a result. But VR helps her manage real-world stressors, more than escaping them. After a long workday, she visits her back porch on Alcove, which overlooks a pond. “It’s my little retreat,” she said. “VR improves my mood. It’s added a lot to my life.”
Some seniors are using more than one technology. Olshansky and Lee discuss strategy while playing Internet chess. And Olshansky recently began using VR. He sees his sister, who lives far away, in a virtual beach house. “It’d be a great way to interact with Hyunseung,” he said. “I should get him a headset.”
A version of this article first appeared in The Washington Post on December 3, 2021.
