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

Manipulating the Microbiome Could help Manage Weight

Published: Thursday, August 30, 2012
Last Updated: Thursday, August 30, 2012
Bookmark and Share
UChicago researchers team was able to unravel some of the mechanisms that regulate this weight gain.

Vaccines and antibiotics may someday join caloric restriction or bariatric surgery as a way to regulate weight gain, according to a new study focused on the interactions between diet, the bacteria that live in the bowel and the immune system.

Bacteria in the intestine play a crucial role in digestion. They provide enzymes necessary for the uptake of many nutrients, synthesize certain vitamins and boost absorption of energy from food.

Fifty years ago, farmers learned that by tweaking the microbial mix in their livestock with low-dose oral antibiotics, they could accelerate weight gain.

More recently, scientists found that mice raised in a germ-free environment, and thus lacking gut microbes, do not put on extra weight, even on a high-fat diet.

In a study published Aug. 26 in the journal Nature Immunology, a research team based at the University of Chicago was able to unravel some of the mechanisms that regulate this weight gain.

They focused on the relationship between the immune system, gut bacteria, digestion and obesity. They showed how weight gain requires not just caloric overload but also a delicate, adjustable - and transmissible - interplay between intestinal microbes and the immune response.

“Diet-induced obesity depends not just on calories ingested but also on the host’s microbiome,” said the study’s senior author Yang-Xin Fu, professor of pathology at the University of Chicago Medicine.

For most people, he said, “host digestion is not completely efficient, but changes in the gut flora can raise or lower digestive efficiency.”

So the old adage “you are what you eat” needs to be modified, Fu suggested, to include, “as processed by the microbial community of the distal gut and as regulated by the immune system.”

To measure the effects of microbes and immunity, the researchers compared normal mice with mice that have a genetic defect that renders them unable to produce lymphotoxin, a molecule that helps to regulate interactions between the immune system and bacteria in the bowel. Mice lacking lymphotoxin, they found, do not gain extra weight, even after prolonged consumption of a high-fat diet.

On a standard diet, both groups of mice maintained a steady weight. But after nine weeks on a high-fat diet, the normal mice increased their weight by one-third, most of it fat. Mice lacking lymphotoxin ate just as much, but did not gain weight.

The high-fat diet triggered changes in gut microbes for both groups. The normal mice had a substantial increase in a class of bacteria (Erysopelotrichi) previously associated with obesity and related health problems.

Mice that lacked lymphotoxin were unable to clear segmented filamentous bacteria, which has previously been found to induce certain immune responses in the gut.

The role of gut microbes was confirmed when the researchers transplanted bowel contents from the study mice to normal mice raised in a germ-free environment - and thus lacking their own microbiome.

Mice who received commensal bacteria from donors that made lymphotoxin gained weight rapidly. Those that got the bacteria from mice lacking lymphotoxin gained much less weight for about three weeks, until their own intact immune system began to normalize their bacterial mix.

When housed together, the mice performed their own microbial transplants. Mice are coprophagic; they eat each other’s droppings. In this way, the authors note, mice housed together “colonize one another with their own microbial communities.”

After weeks together, even mice with the immune defect began to gain weight. They also were able to reduce the presence of segmented filamentous bacteria in their stool.

Moving from normal chow to the high-fat diet initiated a series of related changes, the authors found. First, it altered the balance of microbes in the digestive system. These changes in the microbiome altered the immune response, which then introduced further changes to the intestinal microbial community.

These changes “provide inertia for the obese state,” the authors said, facilitating more efficient use of scarce food resources.

“Our results suggest that it may be possible to learn how to regulate these microbes in ways that could help prevent diseases associated with obesity,” said Vaibhav Upadhyay, first author of the study and an MD/PhD student working in Fu’s laboratory. “We now think we could inhibit the negative side effects of obesity by regulating the microbiota and perhaps manipulating the immune response.”

Or, 20 years from now, “when there are 10 billion people living on earth and competing for food, we may want to tilt digestive efficiency in the other direction,” Fu added.

The authors cautioned, however, that with more than 500 different strains of bacteria present in the gut, “the precise microbes that promote such weight gain and the specific host responses that foster their growth need to be better established.”


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 3,000+ scientific posters on ePosters
  • More than 4,400+ 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

Gut Bacteria Can Dramatically Amplify Cancer Immunotherapy
Manipulating microbes maximizes tumor immunity in mice.
Monday, November 09, 2015
Gut Bacteria that Protect Against Food Allergies Identified
Common gut bacteria prevent sensitization to allergens in a mouse model for peanut allergy, paving the way for probiotic therapies to treat food allergies.
Wednesday, August 27, 2014
Staphylococcus Aureus Bacteria Turns Immune System Against Itself
Around 20 percent of all humans are persistently colonized with Staphylococcus aureus bacteria, including the antibiotic-resistant strain MRSA.
Friday, December 13, 2013
Staphylococcus aureus Bacteria Turns Immune System Against Itself
Scientists use primary human immune defense mechanism to destroy white blood cells.
Thursday, December 05, 2013
Scientific News
Gut Microbiomes Of Infants Have An Impact On Autoimmunity
Exposure to pathogens early in life is beneficial to the education and development of the human immune system.
Understanding Female HIV Transmission
Glowing virus maps points of entry through entire female reproductive tract for first time.
COPD Linked to Increased Bacterial Invasion
Persistent inflammation in COPD may result from a defect in the immune system that allows airway bacteria to invade deeper into the lung.
Finding Factors That Protect Against Flu
A clinical trial examining the body’s response to seasonal flu suggests new approaches for evaluating the effectiveness of seasonal flu vaccines.
Vaccinations Are More Effective When Administered In The Morning
Research from the University of Birmingham shows that influenza vaccinations have more protective responses when administered in the morning.
Secrets of a Deadly Virus Family Revealed
Scripps Research scientists uncover the glycoprotein structure of LCMV. The findings could guide development of treatments for Lassa fever.
Cytokine Triggers Immune Response at Expense of Blood Renewal
Research highlights promise of Anti-IL-1 drugs to treat chronic inflammatory disease.
Reduced Immune Response Causes Flu Deaths in Older Adults
Yale study suggests that immune response to flu causes death in older people, not the virus.
Exposure To Routine Viruses Makes Mice Better Test Subjects
Study shows that infections make mouse immune system act more like that in humans.
Immune Booster Tested in Advanced Merkel Cell Cancer
The immunotherapy drug produced durable responses in many patients.
SELECTBIO

SELECTBIO Market Reports
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
3,000+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,400+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!