The stem cells inside your esophagus

By: Maude Hamilton, Université de Sherbrooke

All organs are made up of billions of cells that play different roles. Think of it like a workplace where all workers, the cells, have a certain job to do and function together to meet a precise goal, in this case to ensure normal function of the workplace (which is the organ). As for a work environment, it is the function of the organ that will determine what type of cells are necessary.

The esophagus is a muscular tube that allows the transport of food from the mouth to the stomach using muscular contractions. It is lined with special cells, called epithelial cells, that have the main role to protect the esophagus against what travels inside of it. Overall, your esophagus is in contact with so many not so cool things (even though it could be delicious things at first). All epithelial cells are a little bit like security guards. They keep extremely hot tea or coffee, toxic alcohol, and even stomach acid during heartburn from damaging your esophagus. Well, they do the best that they can to protect this organ but keep in mind that even your normal food will have an abrasive effect and bring some cells down with it to the stomach.

Unfortunately, that means for the epithelial cells that they continuously die in their line of work. However new cells will soon take their place. This is what is called normal tissue turnover. This tissue maintenance is possible by the presence of a rare type of cells, hidden in the bottom layer of the epithelium: stem cells.

What are stem cells? Adult stem cells are like human resources. They know when the workplace needs new workers, and they hire new ones. But instead of bringing in someone new, they “retrain” to do the job themselves: they gave rise to new epithelial cells that will eventually migrate toward the center of the esophagus and, at their turn, die as well. Stem cells can produce all types of cells necessary for a particular tissue. Those rare cells also have the capacity to self-renew, which means that besides giving birth to different types of cells, they can also multiply forever. Furthermore, they can resist to higher doses of radiation. In short, stem cells are important for the homeostasis, the balance of a tissue.

As for the esophagus, a population of stem cells was recently discovered in the esophageal epithelium. But the mystery remains: how are they really working? What genes are responsible for their stem cell nature? That is in part what the laboratory of the professor Véronique Giroux is trying to find out! Knowing more about stem cells in their normal conditions could help to better understand esophageal diseases. For example, in cancer, stem cells can contribute to treatment resistance, as they are known to have an increased capacity of radiation resistance. Beside that, stem cells can also help with the regeneration of wounds, so maybe by knowing more about their normal functioning, we could find a way to promote regeneration.

Every organ in your body is his own workplace, and even a simple organ as the esophagus as an important role for the harmonious function of your body. As human resources, stem cells are mysterious and are not that well understood. Therefore, research on those rare fellas is necessary to improve our understanding of their function.

Edited by B.G. Borowiec and A.E. McDonald. Header photo from Wikimedia Commons. Other photos by Maude Hamilton.