Intestinal Cells Provide Clues to Irritable Bowel Syndrome Treatment

For irritable bowel syndrome (IBS) sufferers, immune cells responsible for intestinal movement may be the key to an effective treatment.

In a study published July 17 in Cell, researchers highlighted the muscularis macrophage, which lines the intestines and has been found to combat infections.

The exact behavior of the macrophages is fairly uncertain due to the complexity of extracting the cells from the intestines., Milena Bogunovic, assistant professor of microbiology and immunology at Pennsylvania State University (PSU) and one of study’s senior authors said in a statement. While they have been linked to abdominal inflammation, their role has not been identified in healthy patients.

The authors also reported discovering that muscularis macrophages regulated the movement of the colon. They were able to do so because blocking the effect of bone morphogenetic protein 2 (BMP2) mirrored the effects of the macrophage removal. According to PSU, BMP2 is used by enteric neurons, which produce a growth factor called colony stimulatory factor 1 and is integral for macrophage formation.

When the researchers stopped BMP2’s activity in mice, they noted the effect was equivalent to removing the macrophage. Upon macrophage depletion, the mice experienced inconsistent intestine behavior due to defective muscle contraction, Bogunovic commented.

"After macrophage depletion, we observed that the normal intestinal movements are irregular, probably because the muscular contractions were poorly coordinated, suggesting that intestinal movements are regulated by macrophages," Bogunovic said.

Overall, their findings signified that gastrointestinal operation is driven by “microbiota-driven crosstalk between muscularis macrophages and enteric neurons,” the authors wrote.

“By better understanding how the nervous system cells, the muscularis macrophages and signals from inside the intestine interact, we may be able to find new treatments for IBS, or even prevent it," Bogunovic said.