The mystery of why people with Inflammatory Bowel Disease (IBD) have a four times higher risk of getting life threatening blood clots has been solved by scientists in Dublin in research that opens the door to new treatment options.
“This discovery opens the door to potential therapies that target harmful clotting associated with IBD,” said Dr Roger Preston, of the Royal College of Surgeons in Ireland (RCSI) who led research reported in Nature Communications.
According to Crohn’s and Colitis Ireland, at least 40,000 people are living with IBD in Ireland with the number of cases here increasing every year.
The numbers affected globally are estimated at 10 million. It can be diagnosed at any age, and affects males and females equally.
Scientists had previously found a strong link between inflammatory diseases, including IBD, and an increased risk of life-threatening blood clots, but up to now, it was not understood why.
“There are some known risk factors for thrombosis in IBD patients, such as disease severity and being hospitalised,” said Dr Preston.
However, there was no well-defined biological marker in the body, he said, that could predict which IBD patients will experience thrombosis.
“We don’t yet know why IBD patients have an increased risk of thrombosis, so this was the starting point of our study,” said Dr Preston.
The RCSI researchers studied data from the RISK study which looked at children in the USA and Canada newly diagnosed with Crohn’s disease.
They also analysed data from gut biopsies of IBD patients generated by collaborating scientists at Children’s Health Ireland (CHI) at Crumlin.
The research “unexpectedly” found that an immune cell, called a T cell, which was known to trigger IBD, can promote blood clot formation
“The increased presence of these ‘pro clotting’ immune cells in IBD patients may contribute to their heightened clotting risk,” said Dr Preston.
“Encouragingly, we also found that an anti-inflammatory protein in the blood can reduce the clot-promoting activity of these immune cells.”
The researchers found that the T cells causing IBD had a clot-promoting protein displayed on their surface that triggered clots to form whenever it came into contact with the blood.
“We did not observe this pro-clotting activity in T cells isolated from healthy individuals, suggesting it is a feature of the disease,” said Dr Preston.
The scientists also found that a protein that can normally control the clot-promoting behaviour of T cells is not as readily ‘switched on’ or made active, in the guts of people with IBD.
Inflammatory diseases are known to happen when the body’s immune system, which is normally its protector, overreacts to an injury or infection to such an extent that the overreaction itself triggers an inflammatory disease – like IBD.
“There is a growing realisation that inflammation and dysregulated blood clotting are intrinsically linked, so developing drugs that target both processes may provide new therapeutic opportunities,” said Dr Preston.
“Developing new drugs is a lengthy process, but repurposing already approved anti-inflammatory medications for the same purpose could accelerate progress.
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