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
SEP 15, 2020
Immunology
Common Spice Relieves Eye Inflammation in Dogs, Human Studies to Follow
SEP 15, 2020
Common Spice Relieves Eye Inflammation in Dogs, Human Studies to Follow
A therapeutic made from turmeric has been shown to help reduce the effects of a painful inflammatory eye condition in do ...
OCT 26, 2020
Immunology
Gearing up for Life: The First 7 Days of the Immune System
OCT 26, 2020
Gearing up for Life: The First 7 Days of the Immune System
The mother’s placenta serves as a shield for the developing fetus inside the womb, protecting it from the constant ...
NOV 04, 2020
Coronavirus
Damaging Antibodies Can Lead to Blood Clots in COVID-19 Patients
NOV 04, 2020
Damaging Antibodies Can Lead to Blood Clots in COVID-19 Patients
COVID-19, the illness caused by the pandemic virus SARS-CoV-2, is known to cause blood clots all over the body in some p ...
NOV 06, 2020
Drug Discovery & Development
New Vaccine Shows Promise for Herpes
NOV 06, 2020
New Vaccine Shows Promise for Herpes
The World Health Organization estimates that over 500 million people have Herpes Simplex Virus Type 2 (HSV-2), a sexuall ...
NOV 10, 2020
Immunology
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
NOV 10, 2020
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
In the middle of 2020, yet another deadly Ebola outbreak was reported in the Democratic Republic of the Congo - the 11th ...
DEC 01, 2020
Immunology
Scar-Free Healing Starts With Mobilizing the Immune System
DEC 01, 2020
Scar-Free Healing Starts With Mobilizing the Immune System
Thanks to a new hydrogel biomaterial developed by researchers at Duke University, we are one step closer to the holy gra ...
Loading Comments...