In one of the largest studies of its kind ever conducted, an international team of scientists has thrown new light on the genetic basis of the inflammatory bowel diseases (IBD). Crohn's disease and ulcerative colitis, the two most common forms of IBD, are chronic inflammatory digestive disorders affecting 230,000 Canadians.
Dr. John Rioux, researcher at the Montreal Heart Institute and Associate Professor of Medicine at the Université de Montréal, is one of the researchers who have identified 71 genetic regions newly associated with inflammatory bowel disease (IBD), increasing the total number discovered to date to 163, in one of the largest studies of its kind.
Also, the study points out that these regions showed a striking overlap with those implicated in autoimmune diseases and in immune deficiencies. Even more surprising was the observation of a significant overlap with genetic regions controlling our response to microbial infections such as in the case of tuberculosis. These highlights were published in the prestigious scientific journal Nature today.
Moreover, these findings suggest that IBD results from overactive immune defence systems that evolved to fight off serious bacterial infections. In IBD, the body's immune system produces an ongoing inflammatory reaction in the intestinal tract that injures the intestinal wall, leading to diarrhea and abdominal pain. IBD patients typically require lifelong treatment with drug therapy, and often need surgery to repair tissue damage caused by the disease.Common research
In the first step of the study, the researchers conducted a "meta-analysis" of 15 previous genomic studies of either Crohn's disease (CD) or ulcerative colitis (UC), the two most common forms of IBD, creating a large dataset that combined genetic information from some 34,000 individuals who took part in those studies. The results then formed part of a second meta-analysis that included data from new genome-wide scans of more than 41,000 DNA samples from CD/UC patients and healthy comparison subjects collected at 11 centers around the world by the International IBD Genetics Consortium.
"We have greatly expanded the map of genetic regions that are associated with IBD", agreed Dr. John Rioux, co-lead author of this study and chair of the Consortium, with Jeffrey Barrett of the Wellcome Trust Sanger Institute in Cambridge, England, lead author of the study. "Each of these regions only increases a person's chance of developing IBD by a fraction of a per cent and even taken together they cannot tell us who will or will not develop the disease. But they each tell a small story about the biology of this disorder, and by combining them we find biological pathways that, if disrupted, can lead to IBD."Immune system: a major factor
"We see a genetic balancing act between defending against bacterial infection and attacking the body's own cells," said Dr. Barrett. "Many of the regions we found are involved in sending out signals and responses to defend against bad bacteria. If these responses are over-activated, we found it can contribute to the inflammation that leads to IBD."
Nearly 100 scientists in 15 countries contributed to the new work, which "highlights the incredible power that working together in a large team can have," said Barrett. "This would not have been possible without the thousands of DNA samples from patients with these conditions assembled by the International IBD Genetics Consortium. Collectively, our findings have begun to uncover the biological mechanisms behind this disease."About inflammatory bowel diseases
About the Montreal Heart Institute: www.icm-mhi.org.
About the Université de Montréal: www.umontreal.caNotes to Editors:
Published in Nature online November 1st, 2012
William Raillant-Clark | EurekAlert!
Discovery of an unexpected function of a protein linked to neurodegenerative diseases
28.04.2015 | Institute for Research in Biomedicine (IRB Barcelona)
Rubber from dandelions / Scientists identify key components in the formation of rubber
28.04.2015 | Westfälische Wilhelms-Universität Münster
KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.
Daejeon, Republic of Korea, April 23, 2015--Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and...
A very small and rare species of shark is swimming its way through scientific literature. But don't worry, the chances of this inches-long vertebrate biting...
Ever since computers have been small enough to be fixtures on desks and laps, their central processing has functioned something like an atomic Etch A Sketch, with electromagnetic fields pushing data bits into place to encode data.
Unfortunately, the same drawbacks and perils of the mechanical sketch board have been just as pervasive in computing: making a change often requires starting...
How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was discovered, more or less by coincidence, that cosmic rays provide suitable probes to measure electric fields within thunderclouds. This surprising finding is published in Physical Review Letters on April 24th. The measurements were performed with the LOFAR radio telescope located in the Netherlands.
How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was...
Max Planck researcher Buhalqem Mamtimin determines how much nitrogen oxide is released into the atmosphere from agriculturally used oases.
In order to make statements about current and future air pollution, scientists use models which simulate the Earth’s atmosphere. A lot of information such as...
23.04.2015 | Event News
23.04.2015 | Event News
13.04.2015 | Event News
28.04.2015 | Innovative Products
28.04.2015 | Life Sciences
28.04.2015 | Life Sciences