Danish researchers studied the gut microbiota of 176 Japanese centenarians and found their combination of intestinal bacteria and bacterial viruses “unique.” The specific variety of bacteria has shown to be beneficial for overall health and aging through the intestinal flora.
“Intestinal bacteria are a natural part of the human body and of our natural environment and the crazy thing is that we can change the composition of intestinal bacteria,” says Simon Rasmussen, co-author of the new study and associate professor at the University of Copenhagen and Novo Nordisk Foundation Center for Protein Research.
They are exploring whether the gut microbiome impacts aging and if its ecology can prevent diseases, as it influences the systematic immune function.
“We are always eager to discover 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 – disease-promoting – microorganisms,” says Joachim Johansen, first author of the new study and Ph.D. fellow at Novo Nordisk Foundation Center for Protein Research.
“If their intestines are better protected against infection, then that’s probably one of the things that cause them to live longer than others.”
Viruses and bacteria
Published in Nature Microbiology, the study reveals that when gut viromes of younger adults (above 18 years old) and older individuals (above 60 years old) were compared, centenarians showed a more diverse gut virome including previously undescribed viral genera, such as viruses associated with the bacteria Clostridia.
The researchers found protective viruses and great biological diversity in both bacteria and bacterial viruses in the centenarians.
“High microbial diversity is usually associated with a healthy gut microbiome, and we expect people with a healthy gut microbiome to be better protected against aging-related diseases,” says Johansen.
“We cannot change the genes, at least not in the near future. If we know why viruses and intestinal bacteria are a good match, it will be much easier to change something that actually affects our health.”
Rasmussen explains that our intestines contain billions of viruses living off and inside bacteria, and “they couldn’t care less about human cells.” But instead, they infect the bacterial cells, and as there are hundreds of different types of bacteria in our intestines, there are also many bacterial viruses.
The researchers used an algorithm to map the intestinal bacteria and viruses to understand better how to expand a wider population’s life expectancy.
“We want to understand the dynamics of the intestinal flora. How do the different kinds of bacteria and viruses interact? How can we engineer a microbiome to help us live healthy and long lives? Are some bacteria better than others? We can use the algorithm to describe the balance between viruses and bacteria,” says Rasmussen.
“We have learned that if a virus visits a bacterium, it may actually strengthen the bacterium. The viruses we found in the healthy Japanese centenarians contained additional genes that could boost the bacteria,” says Johansen.
“We learned that they were able to boost the transformation of specific molecules in the intestines, which might serve to stabilize the intestinal flora and counteract inflammation.”
Rasmussen adds that if bacteria and viruses are discovered that positively affect the human intestinal flora, the next step is to find out whether only some or all of us have them.
“If we can get these bacteria and their viruses to move in with the people who do not have them, more people could benefit from them,” concludes Rasmussen.
By Beatrice Wihlander