Health: Stress may contribute to flare-ups of Crohn’s disease by weakening the innate immune system

Psychological stress may contribute to flare-ups of Crohn’s disease by impeding the body’s ability to fight off bad gut bacteria like E. coli, a study has suggested.

Crohn’s disease is a long-term condition which can cause inflammation, scarring and ulcers within the body’s digestive tract — most often in the small or large intestine.

It is a debilitating gut condition that affects around 115,000 people in the United Kingdom and almost 3 million globally. 

Working with mice, researchers from McMaster University in Ontario Canada found that stress hormones could suppress the rodents’ innate immune system.

This left them vulnerable to a family of invasive bacteria — ‘Enterobacteriaceae’ — whose members, especially E. coli, have previously been linked to Crohn’s disease.

Psychological stress may contribute to flare-ups of Crohn’s disease by impeding the body’s ability to fight off bad gut bacteria like E. coli, a study has suggested (stock image)

‘The main takeaway is that psychological stress impedes the body’s ability to fight off gut bacteria that may be implicated in Crohn’s disease,’ said paper author and biochemist Brian Coombes of McMaster University.

‘Innate immunity is designed to protect us from microbes that do not belong in the gut, like harmful bacteria,’ he explained.

‘When our innate immune system functions properly, it prevents harmful bacteria from colonising us, but when it breaks down, it leaves an opening for pathogens to colonise locations they normally cannot and cause illness.’

Key to the body’s innate immunity, the team explained, is the correct functioning and maintenance of the gut’s protective lining of epithelial cells.

This barrier relies on molecular signals from immune cells in order to secrete mucus, repair the cell wall and keep out harmful microbes. 

When the innate immune system is suppressed — such as by stress hormones — the the epithelial cellular wall can break down, allowing microbes like E. coli to invade the gut and trigger Crohn’s disease flare-ups.

Symptoms of the inflammatory condition are known to include abdominal pain, blood and mucus in one’s faeces, diarrhoea, fatigue and weight loss.

In their experiments, the team found that blocking the production of stress hormones in their mice models worked to restore proper function to both the immune system and the epithelial cells.

The researchers cautioned that, while their research may eventually pave the way to new treatments for Crohn’s disease, the findings are presently only in the pre-clinical stage — and there is much more work to be done.

‘The more we know about what triggers Crohn’s disease, the closer we come to new treatments and potentially even disease prevention,’ Professor Coombes said.

The full findings of the study were published in the journal Nature Communications.