Gut feeling yields evidence of microbial involvement in autoimmunity

Detective work by scientists is starting to reveal just how profoundly the community of microbes in our guts affect immunity. People “are not one organism — we are a superorganism”, says Emrah Altindis, a biologist and diabetes specialist at Boston College in Newton, Massachusetts. “We’ve evolved with microbes for hundreds of thousands of years. They have been regulating our immune systems.” Some gut microbes spur immune overactivity, studies suggest, whereas others might protect against autoimmune flare-ups.

Scientists have long explored the part that gut microbes play in autoimmune conditions that affect the digestive system, such as Crohn’s disease and type 1 diabetes. But research is also revealing that gut microbes can affect autoimmune processes in far-flung regions, such as the brain. Continuing gut bacterial studies could one day give rise to personalized treatments for autoimmune conditions or even therapies that stop the conditions from emerging.

A fine-tuned mix

Although most autoimmune conditions have a strong genetic component, environmental factors also nudge the immune system to overreact, and gut microbes could be key to this. One line of research suggests that exposure to chemicals such as pesticides, cigarette smoke and mercury could change the gut microbial community in ways that leave people more vulnerable to autoimmune responses2.

There are a few ways in which gut microbes might shape immune response directly, says Eran Elinav, an immunologist and microbial specialist at the Weizmann Institute of Science in Rehovot, Israel. First, some microbes interfere with the gut’s ability to keep ingested substances in the digestive system. If compounds pass through the gut lining, they can promote an overactive immune response — a well-established mechanism in Crohn’s disease4.

Certain microbes also churn out compounds that closely resemble harmless ones produced in the body. Over time, this can train the body to mount a strong autoimmune response to these harmless molecules, causing inflammation and tissue damage in people with ulcerative colitis, type 1 diabetes and lupus.

Important pathways

In autoimmune disorders that directly affect the digestive organs, such as Crohn’s disease and type 1 diabetes, researchers have made advances in fitting gut bacteria into the bigger immunity picture.

Other microbes might help type 1 diabetes to develop by producing molecules that mimic life-sustaining insulin. Viruses in the gut produce peptide molecules that are similar to insulin, which could lead the immune system to attack the insulin producing cells of the pancreas6.

Road to treatment

New studies are exciting because they add concrete detail to researchers’ understanding of how gut microbes drive biological processes involved in autoimmune disease. Microbial immunology is rich in correlational studies, but these do not establish whether microbes bring about a particular autoimmune state, or simply venture in after disease has taken hold. As researchers investigate how certain microbes provoke specific immune responses, they inch closer to when this information could be used to change the treatment of autoimmune disease. Simply put if you have sorted out which microbes are bad for the immune system and are triggering, you can think about mechanisms to deplete them. Ultimately, autoimmune specialists hope to create therapies tailored to the microbiome of individual people. – Source: nature.com



Did you know?

Coffee

Coffee contains lipidic molecules and antioxidant materials which scavenge free radicals and induce the activation of DNA repair and detoxification enzymes.

Health tip

Use nutrients such as fish oil, vitamin C, vitamin D, and probiotics



Health precaution tip

Practice deep relaxation like yoga and deep breathing

See a rheumatologist experienced in addressing autoimmune conditions for autoimmune disease treatment.



STATS

Possible causes

• Genetics

• Diet

• Infections

• Stress

• Exposure to chemicals