Stem Cell

Understanding how the intestine replaces and repairs itself

Image courtesy of Unmesh Jadhav/HMS, DFCI

The inner lining of the gut consists of a single cell layer of intestinal epithelium that forms millions of crypts and villi. Stem cells (shown in green) reside at the bottom of the crypts and replicate daily, generating new cells to maintain the tissue.

Researchers at Harvard Stem Cell Institute, Dana-Farber Cancer Institute, and Harvard Medical School have identified a previously unknown mechanism that plays an important role in the regeneration of the inner intestinal lining. Their findings provide new insights on how this tissue, which undergoes change on a daily basis, maintains itself.

The intestine is the most highly regenerative organ in the human body, regenerating its lining, called the epithelium, every five to seven days. Continual cell renewal allows the epithelium to withstand the constant wear and tear it suffers while breaking down food, absorbing nutrients, and eliminating waste.

In a Cell Stem Cell study, the researchers found that mature cells, instead of other stem cells, were responsible for replenishing the stem cell population in the intestinal crypts — cavities at the bottom of hair-like structures in the intestine — of mice.

“This is a very basic discovery that allows us to deeply understand how a tissue is organized,” said Ramesh Shivdasani, principal faculty member at the Harvard Stem Cell Institute, professor of medicine at the Dana-Farber Cancer Institute and at Harvard Medical School, and senior author of the study.