Navigation Links
Getting better with a little help from our 'micro' friends

PASADENA, Calif.-- A naturally occurring molecule made by symbiotic gut bacteria may offer a new type of treatment for inflammatory bowel disease, according to scientists at the California Institute of Technology.

"Most people tend to think of bacteria as insidious organisms that only make us sick," says Sarkis K. Mazmanian, an assistant professor of biology at Caltech, whose laboratory examines the symbiotic relationship between "good" bacteria and their mammalian hosts. Instead, he says, "bacteria can be beneficial and actively promote health."

For example, the 100 trillion bacteria occupying the human gut have evolved along with the human digestive and immune systems for millions of years. Some harmful microbes are responsible for infection and acute disease, while "other bacteria, the more intelligent ones, have taken the evolutionary route of shaping their environment by positively interacting with the host immune system to promote health, which gives them an improved place to live; it's like creating bacterial nirvana," says Mazmanian.

If bacteria are actively modifying the gut, their work would have to be mediated by molecules. In their recent work, Mazmanian and his colleagues have identified one such molecule, a sugar called polysaccharide A, or PSA, which is produced by the symbiotic gut bacterium Bacteroides fragilis. They have termed this molecule a "symbiosis factor," and predict that many other bacterial compounds with diverse beneficial activities await discovery.

To identify the molecule and its action, the scientists used experimental mice and induced changes to their intestinal bacteria by exposing them to a pathogenic bacterium called Helicobacter hepaticus. This microbe causes a disease in the mice that is similar to Crohn's disease and ulcerative colitis. However, when the animals were co-colonized with B. fragilis, they were protected from the disease--as were animals that were given oral doses of just the PSA molecule.

In particular, Mazmanian and his colleagues found that PSA induced particular immune-system cells called CD4+ T cells to produce interleukin-10 (IL-10), a molecule that has previously been shown to suppress inflammation--and offer protection from inflammatory bowel disease. "Thus, bacteria help reprogram our own immune system to promote health," he says.

"The most immediate and obvious implication is that PSA may potentially be developed as a natural therapeutic for inflammatory bowel disease," says Mazmanian.

Inflammatory bowel disease, a constellation of illnesses that cause inflammation in the intestines, including ulcerative colitis and Crohn's disease, is estimated to affect one million Americans. The rates of inflammatory bowel diseases have skyrocketed in recent years; for example, the incidence of Crohn's disease, a condition that causes debilitating pain, diarrhea, and other gastrointestinal symptoms, has increased by 400 percent over the past 20 years.

The current research, along with other work by Mazmanian and June L. Round, a Caltech postdoctoral researcher, suggests that the interplay between various groups of bacteria living in the intestines has profound effects on human health.

This notion gels with the so-called "hygiene hypothesis." The hypothesis, first proposed two decades ago, links modern practices like sanitation, vaccination, a Western diet, and antibiotic use, which reduce bacterial infections, to the increased prevalence of a variety of illnesses in the developed world, including inflammatory bowel disease, asthma, multiple sclerosis, and Type 1 diabetes. However, it is now clear that increased living standards and antibacterial drugs affect not only infectious microbes, but all of the beneficial ones that we may depend on for our well-being.

"Through societal measures we have changed our association with the microbial world in a very short time span. We don't have the same contact with microbes as we have for millions of years--we just live too clean now," Mazmanian says. So while it is useful to eliminate disease-causing organisms, "perhaps disease results from the absence of beneficial bacteria and their good effects," he suggests. "This study is the first demonstration of that. What it hopefully will do is allow people to re-evaluate our opinions of bacteria. Not all are bad and some, maybe many, are beneficial."


Contact: Kathy Svitil
California Institute of Technology

Related biology news :

1. The sea ice is getting thinner
2. Getting wise to the influenza virus tricks
3. New caledonian crows find 2 tools better than 1
4. Restoring sight, advances in fertility treatments and better visibility for pilots at FIO
5. New CPR promises better results by compressing abdomen, not Chest
6. City birds better than rural species in coping with human disruption
7. Doctors learn to control their own brains pain responses to better treat patients
8. Study reveals that immigrant teenagers eat better than Spanish teenagers
9. New membrane strips carbon dioxide from natural gas faster and better
10. New approach builds better proteins inside a computer
11. People who skip meals: are they better off?
Post Your Comments:
(Date:10/27/2015)... -- Munich, Germany , October ... automatically maps data from mobile eye tracking videos created ... that they can be quantitatively analyzed with SMI,s analysis ... , October 28-29, 2015. SMI,s Automated Semantic Gaze ... tracking videos created with SMI,s Eye Tracking Glasses ...
(Date:10/26/2015)... 26, 2015 ... adds Biometrics Market Shares, Strategies ... well as Emerging Biometrics Technologies: Global ... its collection of IT and Telecommunications ... --> . ...
(Date:10/26/2015)... , Oct. 26, 2015  Delta ID Inc., ... authentication to mobile and PC devices, announced its ActiveIRIS® ... the arrows NX F-02H launched by NTT DOCOMO, INC ... F-02H is the second smartphone to include iris recognition ... in ARROWS NX F-04G in May 2015, world,s first ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... -- SHPG ) announced today that Jeff Poulton ... th Annual Healthcare Conference in New York City ... EST (1:30 p.m. GMT). --> SHPG ) announced today ... the Piper Jaffray 27 th Annual Healthcare Conference in ... 2015, at 8:30 a.m. EST (1:30 p.m. GMT). --> ...
(Date:11/24/2015)... -- Tikcro Technologies Ltd. (OTCQB: TIKRF) today announced that its Annual General Meeting ... Israel time, at the law offices of ... th Floor, Tel Aviv, Israel . ... Izhak Tamir to the Board of Directors; , election of ... approval of an amendment to certain terms of options granted to our ...
(Date:11/24/2015)... FRANCISCO , Nov. 24, 2015  Twist ... announced that Emily Leproust, Ph.D., Twist Bioscience chief ... Jaffray Healthcare Conference on December 1, 2015 at ... Hotel in New York City. --> ... . Twist Bioscience is on Twitter. ...
(Date:11/24/2015)... ... 24, 2015 , ... InSphero AG, the leading supplier of easy-to-use solutions for ... Aregger to serve as Chief Operating Officer. , Having joined InSphero in ... and was promoted to Head of InSphero Diagnostics in 2014. There she ...
Breaking Biology Technology: