19 May is World Inflammatory Bowel Disease Day, providing an opportunity to raise awareness of these chronic diseases which have a profound effect on the quality of life of those who suffer from them. Here’s a one-minute summary:
IBD encompasses two main groups of diseases: Crohn’s disease and ulcerative colitis. Both are characterised by persistent inflammation of the gastrointestinal tract, and both are divided into subgroups. However, they differ in their location and characteristics.
- Ulcerative colitis primarily affects the colon and rectum, causing ongoing inflammation of the intestinal lining.
- Crohn’s disease, on the other hand, can affect any part of the gastrointestinal tract, from the mouth to the anus, and impact all layers of the intestinal wall.
In addition to digestive symptoms, many patients experience extraintestinal symptoms, including arthritis, eye inflammation, skin conditions and chronic fatigue, among others. The disease can have a significant social and emotional impact, particularly on young adults, who tend to be the most affected group and have more social commitments and everyday activities, such as eating out (Q. Guan, J. Immunology Research, 2019).
What causes IBD?
IBD is a multifactorial disease, although the exact cause is not fully understood.
Genetic factors
- There are more than 200 genetic variants associated with an increased risk of IBD, but these alone do not determine the onset of the disease. The three main variants identified in genome-wide association studies (GWAS) are: NOD2 (R702W, G908R and 1007fs), IL23R (rs11209026) and ATG16L1 (rs2241880).
Immunological factors:
- IBD is associated with a dysregulated immune response, whereby the immune system attacks healthy intestinal tissue. This leads to chronic inflammation and the overproduction of cytokines, such as TNF-α, IL-6 and IL-1β.
Environmental factors:
- Smoking, stress, diet and prolonged use of antibiotics or anti-inflammatory drugs may play a role in the onset or exacerbation of symptoms.
Alterations in the intestinal barrier:
- A defect in the integrity of the intestinal mucosa may facilitate the entry of inflammatory substances and trigger an exacerbated immune response.
- A reduction in beneficial bacteria, such as Faecalibacterium prausnitzii and Roseburia spp., which have anti-inflammatory properties, such as producing short-chain fatty acids, such as butyrate.
- An increase in pro-inflammatory bacteria, such as certain strains of Escherichia coli (especially the adherent-invasive strain in Crohn’s disease).
- Decreased microbial diversity, which weakens the gut ecosystem’s ability to resist perturbations. Some microorganisms may activate inflammatory pathways or evade control by regulatory T cells.
The IBD-microbiota relationship
Intestinal dysbiosis can contribute directly to the onset, continuation and worsening of chronic intestinal inflammation.
Patients with IBD have an altered microbiota compared to healthy people.
Is there evidence for probiotics for IBD?
It has to be taken into account that not all patients will respond in the same way, as IBD depends on the aforementioned factors.
- Bifidobacterium longum 35624 has been shown to improve clinical symptomatology in ulcerative colitis in animal models and clinical trials.
- Escherichia coli Nissle 1917 competes with pathogens, modulates the immune response, and strengthens the intestinal barrier.
- Lactobacillus rhamnosus GG. The evidence for its use in IBD is more modest, but some studies in children with ulcerative colitis have shown an improvement in clinical and mucosal response.
At Microomics, we work together with researchers, hospitals and companies to tackle IBD using omics sciences. Studying the microbiome enables us to address dysbiosis and alleviate symptoms, as well as provide evidence about the cause. This is sometimes achieved by examining the faecal microbiome in children.
As IBD is such a complex pathology, reducing bias and methodological errors is fundamental to finding informed answers. This is why adequate sampling design, the selection of appropriate technology and the correct analysis pipeline for correlating data with other variables (e.g. biochemistry) are so important.
Leave us a message on our website and tell us about your project. We will then arrange a free initial meeting to advise you on designing the assay with our 360° platform.
Bibliography: Q. Guan, J. Immunol. Res., 2019; Groeger et al., Gut Microbes, 2013; Kruis et al., Gut, 2004; Bousvaros et al., 2005.