IBD begins when “good” bacteria are mistakenly killed by the immune system, while harmful bacteria multiply — resulting in inflammation and damage to the intestines, and chronic episodes of abdominal pain, cramping, diarrhea and other changes in bowel habits. It’s estimated that IBD, which includes ulcerative colitis and Crohn’s disease, affects 1.4 million people in the U.S., according to the Centers for Disease Control and Prevention.
In test-tube and animal studies, the researchers found that potentially harmful bacteria in the intestine called Enterobacteriaceae use nitrate — a byproduct formed during the intestinal inflammation in IBD — to grow and thrive. Enterobacteriaceae strains include certain E. coli bacteria, which can worsen the intestinal damage of IBD. Eventually, the intestines of those with IBD become overrun by harmful bacteria, and the numbers of normal good bacteria in the gut decrease.
“Much like humans use oxygen, E. coli can use nitrate as a replacement for oxygen to respire, produce energy and grow,” said lead author Andreas Baumler, a professor of medical microbiology and immunology at UC Davis.
“In IBD, nitrate produced by inflammation in the gut allows E. coli to take a deep ‘breath,’ and beat out our beneficial microbes in the competition for nutrients,” he said.
The inflammation in the intestines of those with IBD leads to the release of nitric oxide radicals that are powerful in attacking bacteria, Baumler explained. Yet these nitric oxide radicals are also very unstable, and eventually decompose into nitrate, which can be used by bacteria like E. coli to thrive and grow. By contrast, good bacteria in the gut grows through fermentation — a much slower process.
Determining the reasons why bacteria like E. coli can edge out good bacteria in the gut is crucial for determining new ways to halt the IBD disease process, according to Baumler. Current treatments for IBD suppress the immune response through antibiotics, corticosteroids or other powerful immune-modifying drugs. But long-term side effects can limit their use and their effectiveness for IBD patients.
The UC Davis team’s research indicates that targeting the molecular pathways that generate nitric oxide and nitrate, as well as other molecules that feed harmful gut bacteria, could calm down and normalize the intestinal environment in IBD, Baumler noted. They are already doing research with one candidate drug that could halt the multiple pathways by which harmful bacteria thrive in IBD.
“The idea would be to inhibit all pathways that produce molecules that can be used by bacteria such as E. coli for respiration and growth,” Baumler said. “Essentially you could then smother the bacteria.”
Other study authors include Sebastian E. Winter, Maria G. Winter, Mariana N. Xavier, Parameth Thiennimitr, Victor Poon, A. Marijke Keestra, Ina Popova, Sanjai J. Parikh, Renee M. Tsolis, and Valley J. Stewart of UC Davis; and Richard C. Laughlin, Gabriel Gomez, Jing Wu, Sara D. Lawhon, and L. Garry Adams of Texas A&M University.
This work was supported by the California Agricultural Experiment Station and Public Health Service grants AI089078, AI076246 and AI088122 along with a scholarship from the Faculty of Medicine, Chiang Mai University, Thailand.About UC Davis Health System
Team pinpoints genes that make plant stem cells, revealing origin of beefsteak tomatoes
26.05.2015 | Cold Spring Harbor Laboratory
DNA double helix does double duty in assembling arrays of nanoparticles
26.05.2015 | DOE/Brookhaven National Laboratory
Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.
Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...
Development and implementation of an advanced automobile parking navigation platform for parking services
To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...
The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...
On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.
RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...
Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.
To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...
20.05.2015 | Event News
18.05.2015 | Event News
12.05.2015 | Event News
26.05.2015 | Ecology, The Environment and Conservation
26.05.2015 | Life Sciences
26.05.2015 | Power and Electrical Engineering