Gastrointestinal nematodes infect approximately 2 billion people worldwide, and some researchers believe up until the 20th century almost everyone had worms. In developed countries there is a decreasing incidence of nematode infection but a rising prevalence of certain types of autoimmunity, suggesting a relationship between the two.
Nematode infection has been purported to have therapeutic effects and currently clinical trials are underway to examine worms as a treatment for diseases associated with the relevant cytokines, including inflammatory bowel disease, multiple sclerosis, and allergies.
In the study researchers tested the effect of nematode infection on mice fed a high-fat diet. Infected mice of normal girth gained 15 percent less weight than those that were not infected. Mice that were already obese when infected lost roughly 13 percent of their body weight within 10 days. Infection also drastically lowered fasting blood glucose, a risk factor for diabetes, and reduced fatty liver disease, decreasing liver fat by ~25 percent, and the weight of the liver by 30 percent.
The levels of insulin and leptin also dropped, "indicating that the mice restored their sensitivities to both hormones," says corresponding author Aiping Zhao of the University of Maryland School of Medicine, Baltimore. Leptin moderates appetite. As with too much insulin, too high a level of leptin results in insensitivity, thus contributing to obesity and metabolic syndrome, Zhao explains.
The mechanism of the moderation of these hormones "was associated with a parasite-induced reduction in glucose absorption in the intestine, reduced liver triglycerides, and an increase in the population of cells called "alternatively activated macrophages," which regulate glucose metabolism and inflammation," says coauthor Joe Urban of the United States Department of Agriculture. Some of these changes involved "a protein called interleukin-13 and related intracellular signaling mechanisms," he says. "This suggests that there are immune related shifts in metabolism that can alter expression of obesity and related metabolic syndrome."
The incidence of obesity has been climbing dramatically, worldwide. It is a key risk factor for many metabolic diseases, including diabetes, hypertension, and heart disease. Recent studies indicate that it is accompanied by chronic low-grade inflammation in adipose tissues, causing the release of proinflammatory cytokines and chemokines that contribute to the development of cardiovascular disease and metabolic syndrome.
Parasitic nematode infection induces a marked elevation in host immune Th2-cells and related type 2 cytokines which, besides combating the infection, also have potent anti-inflammatory activity, according to the report.
A copy of the manuscript can be found online at http://bit.ly/asmtip0413d. Formal publication is scheduled for the June 2013 issue of Infection and Immunity.
(Z. Yang, V. Grinchuk, A. Smith, B. qin, J.A. Bohl, R. Sun, L. Notari, Z. Zhang, H. Sesaki, J.F. Urban, Jr., T. Shea-Donohue, A. Zhao, 2013. Parasitic nematode-induced modulation of body weight and associated metabolic dysfunction in mouse models of obesity. Infect. Immun. Published ahead of print 18 March 2013, doi:10.1128/IAI.00053-13.)
Infection and Immunity is a publication of the American Society for Microbiology (ASM). The ASM is the largest single life science society, composed of over 39,000 scientists and health professionals. Its mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.
Jim Sliwa | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy