A persistent mystery in human medicine is how the lining of the small intestine, through which nutrients are absorbed, also prevents intestinal bacteria and their toxins from entering the bloodstream and causing serious infections.
A team of researchers from Massachusetts General Hospital (MGH) has found that a specific intestinal enzyme may be able to block the action of the bacterial toxin involved in the overwhelming infection known as sepsis. The findings, which will appear in the Proceedings of the National Academy of Sciences (PNAS), may also explain why patients recovering from serious injury are less likely to develop infections if they receive gastrointestinal nutrition.
“It’s been known for many years that people who don’t eat, particularly those who are ill or recovering from injury, are more susceptible to infections derived from the gut,” says Richard Hodin, MD, of the MGH Department of Surgery, the study’s senior author. “We know that eating – even small amounts of nutrients delivered through a feeding tube – can help prevent infections, and it may be that the production of this enzyme is the key to that protection. Everyone that takes care of critically ill patients knows the importance of ‘feeding the gut,’ but how that feeding works to prevent infection has been a mystery.”
Intestinal alkaline phosphatase (IAP) is produced by cells lining the small intestine, and several previous studies suggested that IAP might block the action of lipopolysaccharide (LPS), a molecule on the surface of many pathogenic bacteria that is responsible for their toxic effects. In order to investigate the normal function of IAP in the intestine – something that has not been understood – the MGH research team conducted a number of experiments with intestinal cell lines and confirmed that those cells’ expression of IAP could block the toxic effects of LPS.
A comparison of normal mice with mice in whom the IAP gene had been knocked out showed that the animals lacking IAP lost their protection against intestinal bacteria. The investigators also showed that IAP expression and the ability to detoxify LPS were decreased markedly when the animals did not eat for two days, a defect that was reversed when feeding resumed.
“Our results show that IAP produced in the intestinal lining and secreted into the gut can detoxify LPS and prevent bacteria from becoming harmful,” Hodin says. “In addition to explaining how feeding can protect ICU patients from infection, these findings may have significant implications for a variety of conditions, including inflammatory bowel disease. Studies are ongoing to determine the role that IAP may play in those disorders.” Hodin is a professor of Surgery at Harvard Medical School.
Sue McGreevey | EurekAlert!
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy