New link found between gut bacteria and age-related conditions

November 2, 2017, Frontiers

A new study shows for the first time that gut bacteria from old mice induce age-related chronic inflammation when transplanted into young mice. Called "inflammaging", this low-grade chronic inflammation is linked to life-limiting conditions such as stroke, dementia and cardiovasuclar disease. The research, published today in open-access journal Frontiers in Immunology, brings the hope of a potentially simple strategy to contribute to healthy ageing, as the composition of bacteria in the gut is, at least in part, controlled by diet.

"Since inflammaging is thought to contribute to many diseases associated with ageing, and we now find that the plays a role in this process, strategies that alter the gut composition in the elderly could reduce inflammaging and promote healthy ageing," explains Dr Floris Fransen, who performed the research at the University Medical Center Groningen, The Netherlands. "Strategies that are known to alter gut microbiota composition include changes in diet, probiotics, and prebiotics".

Previous research shows that the elderly tend to have a different composition of gut bacteria than younger people. Immune responses also tend to be compromised in the elderly, resulting in inflammaging. Knowing this, Fransen and his team set out to investigate a potential link.

The scientists transferred gut microbiota from old and young conventional mice to young germ-free mice, and analysed immune responses in their spleen, lymph nodes and tissues in the small intestine. They also analysed whole-genome gene expression in the small intestine. All results showed an immune response to bacteria transferred from the old mice but not from the young mice.

The results suggest that an imbalance of the bacterial composition in the gut may be the cause of inflammaging in the elderly. Imbalances, or "dysbiosis" of results in "bad" bacteria being more dominant than "good" bacteria. An overgrowth of bad bacteria can make the lining of the gut become more permeable, allowing toxins to enter the bloodstream where they can travel around the body with various negative effects. Dysbiosis can have serious health implications: several disorders, such as inflammatory bowel disease, obesity, diabetes, cancer, anxiety and autism are already linked to the condition.

"Our gut is inhabited by a huge number of " explains Fransen. "Moreover, there are many different kinds of bacterial species, and the bacterial species that are present can vary a lot from person to person".

Maintaining a healthy gut microbiota is clearly important to a healthy body and healthy ageing, but why the gut microbiota is different in the elderly is not fully understood. Many people are aware of the effect a course of antibiotics can have on the digestive system for example, but as Fransen explains, it may not be down to just one thing: "It is likely a combination of factors such as reduced physical activity, changes in diet, but also as part of a natural process".

Most, if not all, age-related diseases can be linked back to inflammaging. Despite the fact that this particular study was conducted on mice, it is clear that maintaining a healthy gut microbiota is key to a healthy lifestyle. However, more research is needed to confirm that the human body mirrors the mice in this study.

"Both in humans and there is a correlation between altered gut microbiota and inflammaging, but the link between the two remains to be proven in humans" concludes Fransen.

Explore further: New way to prevent unfavorable intestinal microbiota

More information: Floris Fransen et al, Aged Gut Microbiota Contributes to Systemical Inflammaging after Transfer to Germ-Free Mice, Frontiers in Immunology (2017). DOI: 10.3389/fimmu.2017.01385

Related Stories

New way to prevent unfavorable intestinal microbiota

October 25, 2017
The trillions of microbes living in a mammal's intestine play an important role in the host's metabolism and immunity. The composition of microbiota is maintained by antimicrobial proteins secreted from intestinal cells. ...

Changes in gut microbiota after unhealthy diet may protect from metabolic disease

March 17, 2017
An unhealthy diet changes the composition of the gut flora and it is generally assumed that this maladaptation called "dysbiosis" triggers disease. A study by Matteo Serino and his colleagues at the Université Paul Sabatier ...

'Ridiculously healthy' elderly have the same gut microbiome as healthy 30 year-olds

October 11, 2017
In one of the largest microbiota studies conducted in humans, researchers at Western University, Lawson Health Research Institute and Tianyi Health Science Institute in Zhenjiang, Jiangsu, China have shown a potential link ...

Gut bacteria may play a role in Alzheimer's disease

February 10, 2017
New research from Lund University in Sweden has shown that intestinal bacteria can accelerate the development of Alzheimer's disease. According to the researchers behind the study, the results open up the door to new opportunities ...

Gut microbes contribute to age-associated inflammation, mouse study finds

April 12, 2017
Inflammation increases with age and is a strong risk factor for death in the elderly, but the underlying cause has not been clear. A study published April 12 in Cell Host & Microbe reveals that gut microbes are one of the ...

How our gut bacteria affect cancer risk and response to treatment

May 11, 2017
The trillions of bacteria living in our gut (called the gut microbiota) can help determine our risk of cancer, as well as how we might respond to cancer treatment.

Recommended for you

First clues to the causes of multiple sclerosis

May 16, 2018
Multiple sclerosis, which affects one in 1,000 people, is frequently characterised by relapses associated with variable functional impairments including among others vision problems, impairment of locomotor functions or difficulties ...

A high-fiber diet protects mice against the flu virus

May 15, 2018
Dietary fiber increases survival in influenza-infected mice by setting the immune system at a healthy level of responsiveness, according to a preclinical study published May 15th in the journal Immunity. A high-fiber diet ...

Study finds that different diseases elicit distinct sets of exhausted T cells

May 15, 2018
The battle between the human immune system and long-term, persisting infections and other chronic diseases such as cancer results in a prolonged stalemate. Over time battle-weary T cells become exhausted, giving germs or ...

Study shows yogurt may dampen chronic inflammation linked to multiple diseases

May 14, 2018
Inflammation can be good. It's part of the body's innate immune system, our first line of defense against illness and injury.

Beyond killing tuberculosis: How can we tolerate an infection without eliminating a pathogen?

May 11, 2018
Historically, our view of host defense against infection was that we must eliminate pathogens to eradicate disease. However, this perspective has recently been challenged as scientists have taken a lesson from plant biologists ...

Human MAIT cells sense the metabolic state of enteric bacteria

May 9, 2018
A little-explored group of immune cells plays an important role in the regulation of intestinal bacteria. Changing metabolic states of the microbes have an effect on defense cells at different stages of alert or rest, as ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.