What Are Epithelial Cells and Where Are They Found?

Epithelial cells are your first line of defense against contaminants

Our intestinal villi are made up of epithelial cells. Science Photo Library/Getty Images

Epithelial cells — found in our skin, digestive tract, lungs and airway, among other places — have a variety of functions to keep our bodies running well, including guarding against malevolent microbes and helping to transport nutrients into our bloodstreams.

In fact, epithelial cells represent our first line of defense against pathogens and other contaminants that can enter our bodies through our airways, digestive tracts and bloodstreams.

Our skin also is made of epithelial cells, which form a multi-layered watertight barrier between our internal organs and the outside world.

Epithelial (pronounced Eh-pith-ee-lee-ul) cells are arranged in single or multiple layers, depending on where in the body they are. They also can include nerve sensors that allow us to experience taste, touch and smell, and they can secrete mucus that both protects against pathogens and irritants and helps to process nutrients.

Not every epithelial cell performs all of these tasks, of course -- the cells are specialized depending on where in the body they're found.

How Do Epithelial Cells Fit Into Celiac Disease?

Celiac disease can occur when someone who is genetically predisposed to the condition consumes the gluten protein, found in the grains wheat, barley and rye. The protein triggers the person's immune system to attack the epithelial cells known as villi that line the small intestine.

This process, known as villous atrophy, eventually erodes these cells. Because of this, people suffering from celiac disease may also suffer from malnutrition, since they cannot absorb nutrients effectively through their damaged intestinal villi.

The best-known symptoms of celiac disease include diarrhea, fatigue and bloating.

But the condition actually can have more than 100 signs and symptoms, most of which aren't obviously related to the digestive tract.

Do Problems with Epithelial Cells Lead to 'Leaky Gut'?

Possibly. Research indicates that this gluten-triggered attack by the immune system on the body's own epithelial cells in the small intestine may loosen the tight junctions between those cells, which potentially could allow contaminants to leak through the intestinal barrier into the blood stream.

In fact, a potential celiac disease drug known as larazotide acetate targets those junctures in an attempt to retighten them. The drug has been shown in testing to reduce symptoms of celiac disease in people already on a gluten-free diet better than the diet alone, but investigators point out that results are preliminary.

Still, it's far from clear that "leaky gut" actually causes symptoms or health problems.

There's still plenty of research to be done to determine the actual effects, if any, of what's known in some medical circles as "leaky gut syndrome."

Still, there's no denying that the epithelial cells lining your digestive tract (not to mention those located in other parts of your body) are pretty important — without them, we couldn't survive.

(Edited by Jane Anderson)


Davidson College. "Overview of Epithelial Cells." Accessed June 11, 2015.

Leffler DA et al. Larazotide Acetate for Persistent Symptoms of Celiac Disease Despite A Gluten-Free Diet: A Randomized Controlled Trial. 2015 Jun;148(7):1311-1319.

University of Washington. "Celiac Disease." Accessed June 11, 2015.

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