JUN 27, 2018 10:28 AM PDT

Immune Cells Responsible for Chemo-induced Diarrhea

WRITTEN BY: Kara Marker

While studying specific immune cells in the context of chronic itching in the skin, two Washington University School of Medicine scientists discovered that the immune system, rather than the nervous system, is responsible for the uncomfortable and sometimes severe diarrhea that accompanies chemotherapy.

Macrophages trigger smooth muscle contractions in the GI tract. Credit: Center for the Study of Itch

With the results from their new study, these scientists hope that they can develop new ways to treat diarrhea, both in chemotherapy patients and people with diarrhea as a result of gastrointestinal (GI) tract disease.

Diarrhea as a result of chemotherapy is extremely common, afflicting up to 80 percent of chemo patients. In general, diarrhea is a results of abnormal contractions during food digestion in the smooth muscle tissue lining the GI tract. At its worst, diarrhea can be life-threatening or cause cancer patients to quit receiving chemo treatments. People with irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) experience similar diarrhea.

"Diarrhea is a common side effect of chemotherapy that, in severe cases, can lead to death or to patients having to stop lifesaving treatment because often there are no effective therapies to control the diarrhea," explained co-senior investigator Hongzhen Hu, PhD. "This research provides a new avenue to explore in developing drugs to stop such diarrhea."

For a while, scientists thought that nerve cells in the intestines were responsible for chemo-induced diarrhea. But it might actually instead be immune cells called macrophages that are triggering intestinal contractions - the nervous system doesn’t seem to be involved at all.

There are more macrophages in the GI tract than anywhere else in the body. Macrophages are phagocytic cells, which means they engulf dead and dying cells and pathogens and digest them. This process of phagocytosis is an important part of the immune response to infection, cancer, and inflammation.

Researchers discovered that surface receptor TRPV4 on macrophages. The receptor was previously thought to be associated with nerve cells. With TRPV4’s association with GI contractions, the nervous system had been implicated in causing diarrhea.

"We found that the macrophages themselves trigger muscle contractions in the gut without any involvement from neurons," Hu said. "The pathway works in an entirely different way from what we had expected."

The present study was published in the journal Immunity.

Sources: Chemocare, Washington University School of Medicine

About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
MAY 31, 2018
Immunology
MAY 31, 2018
Immunosuppressant Drugs to Prevent Parkinson's Disease
Certain immune activity could be increasing a person’s risk of developing Parkinson’s disease (PD), but immunosuppressant drugs might solve the...
JUN 05, 2018
Clinical & Molecular DX
JUN 05, 2018
"ImmunoPET" Imaging Identifies IBD Inflammation
Scientists are now applying PET imaging to detect inflammation in people with inflammatory bowel disease (IBD). This could help countless IBD patients conn...
JUL 03, 2018
Immunology
JUL 03, 2018
Here's a Virus that Boosts the Immune System
There’s a new therapeutic approach to boosting the weakened immune system that develops naturally with age, but it’s anything but conventional....
JUL 31, 2018
Immunology
JUL 31, 2018
The Immune Systems Molecular Alphabet
Lab-designed nucleic acid nanoparticles elicit varied and specific immune response from immune cells based on shape, size, and formulation of each particle....
AUG 18, 2018
Immunology
AUG 18, 2018
Two Proteins Play Unexpected Role in Immune System Regulators
Two proteins, PLD3 and PLD4, discovered to have role in immune system detection and response to pathogens....
SEP 22, 2018
Immunology
SEP 22, 2018
Could Diet Protect Against Brain Inflammation?
Immune brain cell inflammation due to aging can be mitigated through a high fiber diet...
Loading Comments...