Corporate Banner
Satellite Banner
Immunology
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Charting Microbial Ecosystem of Crohn’s Disease

Published: Thursday, March 13, 2014
Last Updated: Thursday, March 13, 2014
Bookmark and Share
Study analyzed the microbiomes of 447 newly-diagnosed patients with Crohn’s and 221 healthy individuals.

In recent years, there has been a growing awareness that our bodies are not entirely our own: each of us contains a delicate ecosystem comprised not only of human cells, but also trillions of microorganisms – bacteria, viruses, and other assorted “bugs” – that reside in our bodies. Within the human gut, as in any ecosystem, this balance can easily be disrupted, with devastating consequences.

One such consequence could be Crohn’s disease, a chronic condition that affects the gastrointestinal tract. Family history is a well-known risk factor of Crohn’s, but recent research has indicated that an abnormal immune response to the microbes in the gut also plays a role. In astudy published this week in Cell Host & Microbe, scientists have worked out which “bugs” in the gastrointestinal system are at play in the development of the disease.

The study, which was led by researchers from the Broad Institute and Massachusetts General Hospital, analyzed the microbiomes of 447 newly-diagnosed patients with Crohn’s and 221 healthy individuals. One’s microbiome includes the collective genomes of all the microorganisms that are part of the body’s ecosystem. The researchers found that several specific microbes were more prevalent in patients with Crohn’s than in their healthy counterparts, while other bugs were less common in Crohn’s cases. Addressing this dysbiosis, or imbalance, in the microbial ecosystem could be one approach to treating the disease.

Crohn’s is a form of inflammatory bowel disease (IBD) that can affect any region of the gastrointestinal tract, often causing abdominal pain, bleeding, diarrhea, and weight loss. It is an incurable condition that affects over a million people in America alone.

Ever since the microbiome was implicated in Crohn’s, researchers have been trying to understand the troublesome host-microbe interactions that may be at the root of the disease. However, identifying the key microbial players involved has been difficult.

“The challenge in past IBD microbiome studies has been that patients have been recruited at various stages of their disease. These studies captured a snapshot of a microbiome that was not only affected by disease, but also by confounding factors such as treatments or surgery. Our study accounted for these variables,” explained Ramnik Xavier, a senior associate member of the Broad and senior author of the study.

Xavier’s team was able to get a clear picture of the Crohn’s microbial ecosystem by analyzing samples collected from newly diagnosed pediatric patients from 28 different hospitals before the patients were treated for the disease. The samples, which were collected as part of a larger project funded by the Crohn’s and Colitis Foundation of America and the Helmsley Trust, revealed that certain microbiota disappeared in the guts of Crohn’s cases, including some that are thought to promote health, such as the anti-inflammatory bacteria Faecalibacterium prausnitzii. At the same time, several bacteria proliferated in Crohn’s cases, including some that have previously been linked to IBD and one that is known to promote colorectal cancer.

“Knowing these key players is a good starting point for developing therapeutics that target these bugs. We now have a detailed list of organisms to pursue in future studies,” said first author Dirk Gevers, group leader of Microbial Systems and Communities in the Broad’s Genome Sequencing and Analysis Program.

Since three types of samples were collected consistently across all 28 hospitals – biopsied tissue from the ileum (located at the end of the small intestine) and rectum (at the end of the large intestine), as well as stool samples – the researchers were able to determine which sample types were predictive of disease. They found that stool samples were poor predictors, whereas both tissue samples were predictive of Crohn’s no matter where in the gut the patients had the disease. Since the rectum is at the end of the digestive tract, this finding opens up the possibility of using rectal tissue samples as a relatively non-invasive diagnostic test for Crohn’s.

The researchers also noted another interesting finding: while the patients sampled had not yet started on treatment for Crohn’s, roughly 10 percent had been given antibiotics to treat inflammation prior to diagnosis – just before their samples were collected and recently enough for those samples to be affected by the drugs. These patients tended to have an even greater imbalance in their gut microbiota than did other patients, suggesting that follow-up studies should be conducted to determine whether the standard antibiotic treatments for early symptoms of Crohn’s are as beneficial as intended.

Xavier, who is also the chief of the gastrointestinal unit and director of the Center for Inflammatory Bowel Disease at Massachusetts General Hospital and the Kurt Isselbacher Professor of Medicine at Harvard Medical School, said that the next order of business for his team would be to try to determine exactly how the bugs they identified are connected to genes and disease.

“Now that we’ve identified the key organisms at work in Crohn’s, we want to get a functional understanding of the role these microbes and microbial products play in the disease. I think that’s where we’re going to be putting out efforts in the near future,” he said.

This work was supported by the Crohn’s and Colitis Foundation of America, the Army Research Office, the National Institutes of Health, and the Helmsley Trust.

Other Broad researchers who contributed to the study include Curtis Huttenhower, Moran Yassour, Aleksander Kostic, Chengwei Luo, Xochitl Morgan, and Emma Schwager, in collaboration with researchers from several other institutions. Analysis was conducted in conjunction with Curtis Huttenhower’s lab at the Broad and Harvard School of Public Health, and Rob Knight’s lab at the University of Colorado, Boulder.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,900+ scientific posters on ePosters
  • More than 4,200+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

A Cellular Symphony Responsible for Autoimmune Disease
Broad Institute researchers have used a novel approach to increase our understanding of the immune system as a whole.
Monday, November 30, 2015
Researchers Develop a New Means of Killing Harmful Bacteria
Engineered particles are capable of producing toxins that are deadly to targeted bacteria.
Friday, June 26, 2015
Broad Institute & Google Genomics Combine Bioinformatics and Computing Expertise
Both companies explore how to break down major technical barriers that increasingly hinder biomedical research.
Thursday, June 25, 2015
Scientists Make Connection Between Genetic Variation and Immune System
Researchers demonstrate how genetic variations can influence immune cell function.
Tuesday, May 13, 2014
Taking Immune Cells for a Test Drive
Combining biological experimentation on human white blood cells with advanced computational methods can help explain the functional impact of human genetic variation on immune disease.
Monday, March 17, 2014
Circuitry of Cells Involved in Immunity, Autoimmune Diseases Exposed
Connections point to interplay between salt and genetic factors.
Tuesday, June 18, 2013
Surveying Cells, One At a Time
When studying any kind of population — people or cells — averaging is a useful, if flawed, form of measurement.
Wednesday, May 22, 2013
Succinate Levels Linked to Immune Response and Inflammation
Metabolic intermediate plays major role in alerting the immune system - measuring succinate levels may prove effective diagnostic tool in cancer.
Tuesday, May 07, 2013
Scientific News
Food Triggers Creation of Regulatory T Cells
IBS researchers document how normal diet establishes immune tolerance conditions in the small intestine.
Therapeutic Approach Gives Hope for Multiple Myeloma
A new therapeutic approach tested by a team from Maisonneuve-Rosemont Hospital (CIUSSS-EST, Montreal) and the University of Montreal gives promising results for the treatment of multiple myeloma, a cancer of the bone marrow currently considered incurable with conventional chemotherapy and for which the average life expectancy is about 6 or 7 years.
Cellular 'Relief Valve'
A team led by scientists at The Scripps Research Institute (TSRI) has solved a long-standing mystery in cell biology by showing essentially how a key “relief-valve” in cells does its job.
Switch Lets Salmonella Fight, Evade Immune System
Researchers at the University of Illinois at Chicago have discovered a molecular regulator that allows salmonella bacteria to switch from actively causing disease to lurking in a chronic but asymptomatic state called a biofilm.
Tricked-Out Immune Cells Could Attack Cancer
New cell-engineering technique may lead to precision immunotherapies.
Neural Networks Adapt to the Presence of a Toxic HIV Protein
HIV-associated neurocognitive disorders (HAND) afflict approximately half of HIV infected patients.
HIV Protein Manipulates Hundreds of Human Genes
Findings search for new or improved treatments for patients with AIDS.
Breaking the Brain’s Garbage Disposal
The children’s ataxia gene problem turned out to be not such a big deal genetically — it was such a slight mutation that it barely changed the way the cells made the protein.
Flesh-Eating Bacteria Work Together
Scientists recently discovered different strains of deadly flesh-eating bacteria working together to spread infection and they now have a better understanding of the role of the toxins they produce. The discovery could change how the illness and other diseases are treated.
Utilizing Antibodies from Ebola Survivors
A collaborative team from The University of Texas Medical Branch at Galveston, Vanderbilt University, The Scripps Research Institute and Integral Molecular Inc. have learned that antibodies in the blood of people who have survived a strain of the Ebola virus can kill various types of Ebola.
SELECTBIO

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!