Into the Wormhole

Researchers study how roundworm infection can promote intestinal healing

(RxWiki News) A man with ulcerative colitis swallowed worm eggs. Researchers took the opportunity to investigate how worms can promote healing in the intestine.

The findings of the researchers from NYU Langone Medical Center and the University of California at San Francisco suggest that infection with Trichuris trichiura (a roundworm that infects the lower intestine) can increase the colon's mucus production, thus providing relief from symptoms of inflammatory bowel disease.

According to P'ng Loke, Ph.D., assistant professor of medical parasitology at NYU Langone Medical Center and one of the study's authors, using worms to treat colitis is not a novel idea. However, the process by which this therapy might work is not fully understood.

In order to further understand how this roundworm infection encourages healing in the intestine, Loke examined blood and tissue samples taken from a man with ulcerative colitis who ate roundworm eggs after reading scientific literature on the topic. The man's colitis improved significantly in the months after he ingested the eggs. He remained in remission for nearly three years.

Tissues samples taken when the patient had active disease were found to contain high numbers of a type of immune cell that produces an inflammatory protein called interleukin-17. Tissue samples taken after exposure to the worms, when the disease was in remission, contained an abundance of T cells that produce interleukin-22, a protein important in mucosal healing. According to the researchers, it seems as though the immune system activates specific cells in order to increase production of mucous in the colon.

Essentially, says Dr. Loke, the roundworms provoke a huge sneeze of the gut, which is potentially a favorable side effect for ulcerative colitis.

Despite the apparent benefit found in this one case, Dr. Loke has reservations about using roundworm infection to treat colitis. He notes that the worms can cause damage to the gut as well, possibly worsening inflammation of the bowel.

As of now, it is hard to tell who might be helped and who might be hurt by roundworm infection. As such, studies using pigs (a less risky subject than humans) are currently underway.

Ulcerative colitis is a form of inflammatory bowel disease that affects an estimated 619,000 people in the United States. In 2004, the disease was responsible for 82,000 hospitalizations and 311 deaths.

The study by Dr. Loke and colleagues is published in Science Translational Medicine.

Review Date: 
February 22, 2011