worm infection counters inflammatory bowel disease by changing gut microbiome

sciencedaily |   Infection with worms counters inflammatory bowel diseases (IBD) by triggering immune responses that change the mix of bacteria, or microbiome, in the gut. This is according to a study published online April 14 in the journal Science.

The study results support the hygiene hypothesis which, in the case of IBD, argues that the absence of exposure to worms in too-clean modern living spaces has left some with oversensitive, gut-based immune systems vulnerable to inflammatory diseases. Gut worms have helped to train and balance immune systems throughout human evolution, but are now missing in developed nations, which, in turn, have the highest rates of Crohn's disease and ulcerative colitis.

In the newly published study, a team led by researchers from NYU Langone Medical Center found that mice infected with intestinal worms experienced as much as a thousand-fold decrease in Bacteroides -- a group of bacterial species linked by past studies to higher risk for IBD. At the same time, the number of Clostridia, a bacterial species known to counter inflammation, increased tenfold. The investigators argue that the immune response to the worms triggers the growth in Clostridia, which then either outcompete Bacteroides for nutrients or release toxins harmful to Bacteroides.

"Our findings are among the first to link parasites and bacteria to the origin of IBD, supporting the hygiene hypothesis," says study co-senior investigator and parasitologist P'ng Loke, PhD, an associate professor at NYU Langone. Loke says this model may also be applicable to other autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, and type 1 diabetes, in which processes meant to attack foreign invaders instead become oversensitive and react to the body's own cells.

gum disease opens up the body to a host of infections

sciencenews |  For centuries, the mouth and the body have been disconnected — at least when it comes to health care. Through the Middle Ages and beyond, teeth fell under the care of barbers, who could shave a customer and pull a molar with equal skill. In the 1700s, French surgeon Pierre Fauchard published the Treatise on Teeth, establishing dentistry as its own science.

Across the channel in England, as physicians gained stature in the 19th century, surgeons and dentists engaged in a power struggle. In the modern United States, after medicine became linked to employer insurance and Medicare, the fissure between medicine and dentistry widened. Insurance coverage began at the throat.

So when Salomon Amar, a periodontal specialist at Boston University, began exploring links between oral bacteria and heart disease in animal studies in the late 1990s, reactions were lukewarm. “Many cardiologists thought we were a bit crazy,” he says. Skepticism still abounds, but the same molecular tools that have dramatically changed understanding of the gut microbiome are now allowing scientists to track and examine bacteria in the mouth. Advocates of a connection between the artery disease atherosclerosis and microbes are hoping to find convincing proof of their suspicions, while exploring links between ailing gums and other conditions, including cancer, arthritis, diabetes and even Alzheimer’s disease.

The work has profound implications for public health, given that more than 65 million American adults are thought to have periodontal disease, which occurs when bacterial overgrowth inflames the gums and can lead to erosion of gums and bone. If it turns out that periodontal decay drives other diseases, doctors would have a new, and relatively simple, means of prevention.

Wenche Borgnakke, a dental researcher at the University of Michigan in Ann Arbor, has been making this case for years, citing “solid evidence that periodontal treatment has an effect on systemic disease.” She points to a study published last year in the journal Medicine comparing patients on dialysis who received periodontal treatment with those who did not. Those getting treatment had an almost 30 percent lower risk of pneumonia and hospitalization from infections. Another study published earlier this year found that gum disease is associated with a roughly 10 percent higher mortality over 10 years among patients with kidney problems.