Featured Research

from universities, journals, and other organizations

New light on the genetic basis of inflammatory diseases

Date:
November 1, 2012
Source:
Montreal Heart Institute
Summary:
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.

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.

Dr. John Rioux, researcher at the Montreal Heart Institute and Associate Professor of Medicine at the Universitι de Montrιal, 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.

The research was published Nov. 1 in the journal Nature.

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

Up until this point, researchers have been studying Crohn's disease and ulcerative colitis separately. This study was based on the fact that there seems to be a vast amount of genetic overlap between the two disorders.

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

Dr. Rioux and the international team of researchers also studied the activity of genes in their IBD regions in hundreds of different types of cells involved in the immune system. They found that certain cells tended to produce more of these IBD genes, including many that are involved in the body's first line defence against invasion. This illustrates that an immune response seems to be a major factor in IBD: when a bacterium is detected, these cells are not just activated, but become overactive.

"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

IBD results from inflammation in the digestive system and affects 2.5 million people worldwide. With over 230,000 cases, Canada has among the highest frequency of people with IBD in the world. Although it can affect any age group IBD is more likely to develop in teens and adults between 15 and 30 years of age. IBD is a lifelong debilitating condition. It can have a devastating impact on the physical and social lives of those affected.


Story Source:

The above story is based on materials provided by Montreal Heart Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. Luke Jostins, Stephan Ripke, Rinse K Weersma, et al. Host–microbe interactions have shaped the genetic architecture of inflammatory bowel disease. Nature, 2012; DOI: 10.1038/nature11582

Cite This Page:

Montreal Heart Institute. "New light on the genetic basis of inflammatory diseases." ScienceDaily. ScienceDaily, 1 November 2012. <www.sciencedaily.com/releases/2012/11/121101153601.htm>.
Montreal Heart Institute. (2012, November 1). New light on the genetic basis of inflammatory diseases. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2012/11/121101153601.htm
Montreal Heart Institute. "New light on the genetic basis of inflammatory diseases." ScienceDaily. www.sciencedaily.com/releases/2012/11/121101153601.htm (accessed October 1, 2014).

Share This



More Health & Medicine News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Cases Keep Coming for Monrovia's Island Hospital

Ebola Cases Keep Coming for Monrovia's Island Hospital

AFP (Oct. 1, 2014) — A look inside Monrovia's Island Hospital, a key treatment centre in the fight against Ebola in Liberia's capital city. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Ebola Puts Stress on Liberian Health Workers

Ebola Puts Stress on Liberian Health Workers

AP (Oct. 1, 2014) — The Ebola outbreak is putting stress on first responders in Liberia. Ambulance drivers say they are struggling with chronic shortages of safety equipment and patients who don't want to go to the hospital. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Doctors Reassure Public Ebola Patient Won't Cause Outbreak

Doctors Reassure Public Ebola Patient Won't Cause Outbreak

Newsy (Sep. 30, 2014) — After the announcement that the first U.S. patient had been diagnosed with Ebola, doctors were quick to say a U.S. outbreak is highly unlikely. Video provided by Newsy
Powered by NewsLook.com
TX Hospital Confirms Patient Admitted With Ebola

TX Hospital Confirms Patient Admitted With Ebola

AP (Sep. 30, 2014) — Medical officials from Texas Health Presbyterian Hospital confirm they are treating a patient with the Ebola virus, the first case found in the US. (Sept. 30 Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins