Science: Don't lie to me! Parasites are expected to treat autoimmune diseases

Dr. P'ng Loke and Dr. Ken Cadwell studied bacterial plates at the Cadwell Laboratory at the Sigbauer Institute of Biomolecular Medicine, New York University's Lange Medical Center.

Inflammatory bowel disease (IBD) is a special chronic intestinal inflammatory disease, mainly including Crohn's disease and ulcerative colon. Clinically, the symptoms of IBD are repeated abdominal pain, diarrhea, mucus and bloody stools, and even various systemic complications such as blurred vision, joint pain, and rash. IBD can be improved after treatment, but it can also be relieved by itself. However, most patients have recurrent episodes, and a considerable number of patients require surgery for complications.

According to a new study, researchers from institutions such as the University of New York's Langone Medical Center have found that parasitic infections can cause beneficial changes in the microbiota in the gut, which may be used to treat inflammation. Enteropathy (IBD). The relevant research results were published online in the Science Journal on April 14, 2016, and the title of the paper is "Helminth infection promotes colonization resistance via type 2 immunity".

In the case of IBD, these findings support a hygienic hypothesis: in a modern living space that is too clean, the lack of parasite exposure makes some people's gut immune system too sensitive and prone to inflammatory diseases. In human evolution, intestinal parasites help to train and balance the host immune system, but today they are missing in developed countries, while at the same time, the incidence of Crohn's disease and ulcerative colon is also highest in developed countries.

In this new study, the researchers found that Bacteroides, a class of bacteria associated with higher IBD risk, has been found in past studies in mice infected with intestinal parasites. --- The number in the intestines has dropped by a factor of 1000. At the same time, the number of Clostridia has increased tenfold as a class of bacteria known to resist inflammation. The researchers point out that the immune response to these parasites triggers the growth of Clostridium, which then either competes with Bacteroides or releases toxins that can harm Bacteroides.

"The discovery is one of the first people to associate parasites and bacteria with the cause of IBD," said Dr. P'ng Loke, co-author of the paper and an associate professor at the Langueney Medical Center at New York University. Said, this model may be applicable to other autoimmune diseases, including multiple sclerosis, rheumatoid arthritis and type 1 diabetes.

The key finding of the study was that the researchers found that in a rural area of ​​Malaysia where the incidence of IBD was low but the rate of parasitic infection was high, the gut microbiome of these people was more likely than the nearby urban population. Significantly more Clostridium and significantly less Bacteroides.

"The study may change scientists and physicians," said co-author of the paper, Dr. Ken Cadwell, assistant professor of microscientists at the University of New York at the Langerney Medical Center, and a microbiologist, Dr. Ken Cadwell. How do we think about treating IBD. The patient's post-meal talk may make many people think that the parasite directly cures the IBD, but in fact, they act on the intestinal bacteria that are thought to cause the disease."

In 2012, the Loke research team published a paper in the journal PLoS Pathogens (doi: 10.1371/journal.ppat.1003000): They found that parasite eggs were inoculated into monkeys so that they did not develop IBD. Parasitic eggs may be able to trick the host immune system into thinking that this is a parasitic infection that triggers a specific parasite-associated immune response against intestinal inflammation.

According to Cadwell, in the same vein, future treatments may include allowing patients to take immune chemicals, such as interleukin-13 (IL-13), produced by immune cells during parasitic infections. Such treatments may be acceptable to patients because they know they are unlikely to eat parasites during this treatment.

As part of this new study, the researchers fed mice lacking the NOD2 gene with 10 to 15 parasitic whipworms (a worm), in which NOD2 deficiency and several immunitys, including IBD. The disease is closely related. After these worms matured, the researchers measured the number of Bacteroides and Clostridium in the gut and feces of these mice and noted whether IBD still existed. They found that many of the symptoms of IBD, such as intestinal bleeding and ulcers, disappeared with almost all of the Bacteroides in the intestine, but the levels of Clostridia in their intestines increased significantly.

As part of the study, the researchers compared bacteria found in the intestines of 75 indigenous people in rural Malaysia (Orang Asli) with 20 people living in Kuala Lumpur. They found that rural people had fewer Bacteroides than urban residents.

Cadwell said he and Loke plan to study how Clostridium wins in competition with Bacteroides and look for harmless Clostridium species that still induce this effect. In addition, they intend to study how parasites alter intestinal bacteria in order to lay the foundation for the treatment of several inflammatory diseases.