Navigation Links
Getting better with a little help from our 'micro' friends
Date:5/28/2008

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
ksvitil@caltech.edu
626-395-8022
California Institute of Technology
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:12/8/2016)... PUNE, India , Dec. 8, 2016 Market Research ... and Service Market. The global Mobile Biometric Security and Service Market ... period 2016 to 2022. Market Highlights: ... , , ... fast pace due to the increasing need of authentication and security ...
(Date:12/7/2016)... -- According to a new market research report "Emotion Detection and ... Recognition), Service, Application Area, End User, And Region - Global Forecast to 2021", ... Billion in 2016 to USD 36.07 Billion by 2021, at a Compound Annual ... ... MarketsandMarkets Logo ...
(Date:12/7/2016)... Avanade is helping Williams Martini Racing, one of ... biometric data in order to critically analyse every aspect ... against their rivals after their impressive, record-breaking pit stop ... with Williams during the 2016 season to capture and ... rate, temperature and peak acceleration) for key members of ...
Breaking Biology News(10 mins):
(Date:1/12/2017)... MERIDEN, Conn. , Jan. 12, 2017 /PRNewswire/ ... development company and maker of Flublok Influenza ... based Zika vaccine candidate had good safety results ... virus in preclinical studies. The product is expected ... next few months.  In addition, the Institute of ...
(Date:1/12/2017)... ... January 12, 2017 , ... In ... the platform to accommodate increasingly complex and sophisticated deployments, resulting in better ... In addition to these improvements, the latest release brings enhanced data import/export ...
(Date:1/11/2017)... ... January 11, 2017 , ... As a graduate student, ... the pathogens that cause malaria and tuberculosis. Seeing firsthand the ravages those diseases ... Now, as an assistant professor of biology and biotechnology at Worcester Polytechnic Institute ...
(Date:1/11/2017)... ... January 11, 2017 , ... ... and costing healthcare systems more than $23.7 billion, healthcare systems are looking ... , Among the most common sepsis-causing pathogens are bacteria and the yeast pathogen ...
Breaking Biology Technology: