Ulcerative colitis, a type of inflammatory bowel disease (IBD), is less common in countries endemic for helminth infections, suggesting that helminth colonization may have the potential to regulate intestinal inflammation in IBD. Therapeutic effects of experimental helminth infection have been reported.According to a researcher: "What we found was that after worm infection, the regions of the colon that were previously not making mucus, were now making mucus again."
"That's a key factor in healing, and it looked like the mucus came back because the worms were causing the body to produce IL-22. This is a molecule that promotes epithelial growth and healing."
Studies suggest parasites can regulate the immune system in ways that prevent it from "going wild" and attacking healthy tissue, and possibly human evolution took that into account.
A case report in the journal Science Translational Medicine provides a cellular and molecular portrait of dynamic changes in the intestinal mucosa of an individual who infected himself with Trichuris trichiura to treat his symptoms of ulcerative colitis.
Tissue with active colitis had a prominent population of mucosal T helper (TH) cells that produced the inflammatory cytokine interleukin-17 (IL-17) but not IL-22, a cytokine involved in mucosal healing.
After helminth exposure, the disease went into remission, and IL-22–producing TH cells accumulated in the mucosa. Genes involved in carbohydrate and lipid metabolism were up-regulated in helminth-colonized tissue, whereas tissues with active colitis showed up-regulation of proinflammatory genes such as IL-17, IL-13RA2, and CHI3L1.
T. trichiura colonization of the intestine may reduce symptomatic colitis by promoting goblet cell hyperplasia and mucus production through TH2 cytokines and IL-22. Controlled helminth infections may lead to new therapies for inflammatory bowel diseases.
References:
A case report in the journal Science Translational Medicine provides a cellular and molecular portrait of dynamic changes in the intestinal mucosa of an individual who infected himself with Trichuris trichiura to treat his symptoms of ulcerative colitis.
Tissue with active colitis had a prominent population of mucosal T helper (TH) cells that produced the inflammatory cytokine interleukin-17 (IL-17) but not IL-22, a cytokine involved in mucosal healing.
After helminth exposure, the disease went into remission, and IL-22–producing TH cells accumulated in the mucosa. Genes involved in carbohydrate and lipid metabolism were up-regulated in helminth-colonized tissue, whereas tissues with active colitis showed up-regulation of proinflammatory genes such as IL-17, IL-13RA2, and CHI3L1.
T. trichiura colonization of the intestine may reduce symptomatic colitis by promoting goblet cell hyperplasia and mucus production through TH2 cytokines and IL-22. Controlled helminth infections may lead to new therapies for inflammatory bowel diseases.
References:
Eat Your Worms: The Upside Of Parasites. NPR.
M. J. Broadhurst, J. M. Leung, V. Kashyap, J. M. McCune, U. Mahadevan, J. H. McKerrow, P. Loke, IL-22+ CD4+ T Cells Are Associated with Therapeutic Trichuris trichiura Infection in an Ulcerative Colitis Patient. Sci. Transl. Med. 2, 60ra88 (2010).
M. J. Broadhurst, J. M. Leung, V. Kashyap, J. M. McCune, U. Mahadevan, J. H. McKerrow, P. Loke, IL-22+ CD4+ T Cells Are Associated with Therapeutic Trichuris trichiura Infection in an Ulcerative Colitis Patient. Sci. Transl. Med. 2, 60ra88 (2010).
Helminth Trichuris suis (pig whipworm) had no effect as therapy for allergic rhinitis
Ulcerative Colitis - NEJM update, 2011.
Ulcerative Colitis - NEJM update, 2011.
Image source: Trichuris egg in stool sample (40x). Wikipedia, GNU Free Documentation License, Version 1.2.
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