Genetic study reveals link between brain and gut health

An international genetic study, co-led by the Spanish research center CIC bioGUNE and in which more than 50,000 people affected by irritable bowel syndrome (IBS) have participated, reveals a “close relationship” between the health of the brain and the gut, and paves the way for the development of new treatments.

The researchers discovered that the symptoms of IBS can be caused by the same biological processes that produce conditions such as anxiety, as reported by the Basque center.

IBS is a common ailment around the world, affecting around one in ten people, causing a wide range of symptoms including pain, bloating, and intestinal dysfunction.

The diagnosis is usually made after ruling out other possible conditions like Crohn’s disease or bowel cancer.

The disease can often be inherited and is also more common among people who are prone to anxiety.

The causes are not well understood, but an international team, co-led by researchers from CIC bioGUNE, identified several genes that provide clues to the origins of irritable bowel syndrome.

The research team, which includes more than 40 institutions, analyzed the genetic data of 40,548 patients with irritable bowel syndrome from the UK Biobank and 12,852 from the Bellygenes initiative, a global study aimed at identifying genes linked to IBS coordinated by Mauro D’Amato, professor at the Basque Foundation for Science-Ikerbasque and leader of the Gastrointestinal Genetics group at CIC bioGUNE, based in Vizcaya.

The results of the study, which will be published in Nature Genetics, showed that, in general, the heritability of IBS is low, which “probably reflects the importance of other factors such as diet, stress and behavior patterns that can also be shared. in the family environment ”.

However, and given that the symptoms of IBS affect the intestine, the researchers considered it feasible that the genes associated with an increased risk of the disease were expressed in these organs, but found that, instead, the altered genes “are predominantly expressed in the brain tissue or the nerves within the gut that receive their signals from the brain ”.

The researchers also looked for the overlap between susceptibility to IBS and other diseases. They found that the same genetic makeup that puts people at higher risk for IBS increases the risk of common mood disorders such as anxiety, depression and neurotic-like problems, as well as insomnia.

However, the researchers emphasize that this does not mean that anxiety causes IBS symptoms or vice versa.

Current treatments for irritable bowel syndrome vary widely and include changes in diet, medications that target the gut or brain, or changes in habits.

The study suggests that therapies that target neuronal function may be a possible future avenue for research.

“We anticipate that future research will build on our findings, both by investigating the identified target genes, and exploring the shared genetic risk between conditions to improve understanding of the disordered brain-gut interactions that characterize irritable bowel syndrome,” said the first author of the study, Chris Eijsbouts.

This research received funding and support from the Ministry of Economy and Competitiveness (Instituto Salud Carlos III), the Department of Health of the Basque Government and the Swedish Research Council (Vetenskapsradet), among other entities.