Glycocalyx

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The glycocalyx is a thin, sugar-rich coating that covers most cells. It’s made of proteins and fats with sugars attached and acts like an ID badge and a protective shield for the cell.

Endothelial glycocalyx
- On the lining of blood vessels, this coating helps control what leaks in and out of vessels and how cells in the blood interact with the vessel wall.
- It also helps prevent red blood cells from sticking to inner walls and supports normal blood flow. It can sense and respond to the flow of blood, partly by helping produce nitric oxide, which relaxes blood vessels.
- The glycocalyx can vary in thickness, from very thin to relatively thick, depending on where it is and how it’s measured.
- If the glycocalyx is damaged or shed, the vessel becomes more permeable and inflammation can rise. This damage is seen in conditions like high blood sugar, inflammation, ischemia, infections, and sepsis.
- Certain enzymes can break down the glycocalyx, and factors like inflammation, oxidized cholesterol and abnormal blood flow can contribute to its loss. Damage can lead to edema and increased risk of clotting.

Bacterial glycocalyx
- Bacteria also have a glycocalyx, which can appear as a capsule (a tight, well-defined layer) or a slime layer (a diffuse coat).
- This coating helps bacteria stick to surfaces, form biofilms, and protect them from immune attacks.
- In nature and the body, bacteria may be surrounded by this protective layer when they attach to teeth, rocks, or tissues, or live in places like the gut.

Glycocalyx in digestion
- A version of the glycocalyx is found on the microvilli of intestinal cells. It provides extra surface area for absorption and hosts digestive enzymes that help finish breaking down proteins and sugars.