08 Apr Is a vaccine for IBS in the future?
April 8, 2019
Irritable bowel syndrome (IBS) describes a diverse range of symptoms from constipation to diarrhea. Researchers are figuring out the science behind the different symptoms and classifying them into subtypes in a way that affects the course of treatment. ETP spoke with Dr. Mark Pimentel to discover where the next breakthroughs will be.
IBS can be divided into four subtypes. IBS with diarrhea predominance is IBS-D. IBS with constipation predominance is IBS-C. IBS with both is IBS-M, and IBS that is difficult to categorize is IBS-U. It was previously thought that IBS more commonly affected women, but now that we know more about the subtypes, it turns out that is particularly true of IBS-C. On the other hand, IBS-D is more common in men, especially the more severe cases. IBS-M almost evenly affects both men and women.
One commonality between IBS-D and IBS-M is that they may both be triggered by food poisoning. Food poisoning is now believed to be the culprit in 60-70% of the cases of IBS-D and IBS-M. Interestingly, people who develop IBS-D and IBS-M after food poisoning often have antibodies against cytolethal distending toxin B (anti-CdtB) and vinculin (anti-vinculin) in their blood, while it is much less common for these antibodies to be in people with IBS-C. This evidence highlights that the long-term solution and possible cure for IBS will vary depending on the subtype of IBS.
One angle for future treatments involves the gut microbiome, where again there are gender differences. When methane producing bacteria, like Methanobrevibacter smithii and Methanobacterium ruminatum, are in excess, IBS symptoms are common. When men have an excess of Methanobrevibacter smithii and/or Methanobacterium ruminatum they tend to develop IBS-M. Meanwhile, women with the same overgrowth tend to develop IBS-C. Hopefully future studies will shed light on the reasons behind this. In the meantime, doctors can use the information we have about the different subtypes to develop more individualized treatment plans.
One new piece of information that can be used in developing treatment plans comes from Gemelli Biotech. It is a blood test for IBS called ibs-smart, currently available in the United States and soon to be available in the Middle East and Northern Africa. ibs-smart tests for the presence of two antibodies, anti-CdtB and anti-vinculin. Anti-CdtB can be detected in the blood as early as three weeks after a case of food poisoning, while anti-vinculin takes a bit longer to show up. Anti-vinculin can be detected after three months. By six months the levels of both antibodies are elevated. The theory is that higher levels of anti-vinculin are probably associated with more damage to the intestine and therefore more severe IBS-D symptoms.
While there is much to learn about the IBS subtypes and the underlying causes, we do know now that there are direct links between food poisoning and IBS because of work by Dr. Pimentel’s research group and others. In theory, if the severity of a case of food poisoning was lessened or the duration of symptoms was shortened, IBS may be avoidable. Even better, if food poisoning could be avoided all together, maybe it wouldn’t lead to IBS. In the future, there might be a vaccine available that would do just that! Make sure you follow ETP on social media and sign up for email updates to stay up-to-date as this exciting research progresses.