The relationship between cytokines and inflammation is a complex one, but there are a few key factors to be aware of, because cytokines are always present with inflammation. There are many types of cytokine, but the ones that are involved with inflammation interact with the immune system. In order to grasp the science behind inflammation, understanding the role of cytokines is vital.
Cytokines are small proteins produced by cells, and mediate between other cells for normal functioning by reacting with certain cell receptors. They also help cells communicate, as well as trigger certain reactions in other cells. When they are released by their creator cells into tissue or into the circulatory system, they locate their target cells and interact with specific receptors, called binding sites, on the target cells by attaching to them. This interaction triggers a particular action or response by the target cell.
In the case of inflammation, certain cytokines trigger responses to fight infection or injury. The body responds by targeting the injured or infected area with other cells to fight the damage. The body then becomes red, swollen, and warm in the affected area, due primarily to increased blood flow. There are two types of inflammation, acute and chronic. Acute inflammation is primarily due to injury or infection, whereas chronic inflammation is usually caused by a malfunction of the body’s immune system. Chronic inflammation can lead to long term damage.
The types of cytokines involved in the relationship between cytokines and inflammation are numerous. They function not only to incite inflammation, but also to inhibit it. Cytokines essentially help keep the balance of the body in regards to inflammation.
One example of this complex interplay is the two cytokines known as Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-6 (IL-6.) TNF-Alpha is a cytokine that is active during the acute phase of inflammation and induces inflammation. Interleukin-6 (IL-6) is another cytokine, but it reduces inflammation by inhibiting TNF-alpha, although it also has pro-inflammatory functions as well.
The relationship between cytokines and inflammation is also apparent in the treatment of inflammation. In cases of acute inflammation, there is usually no need for intervention other than reduction of symptoms, as it will eventually stop. In cases of chronic inflammation, which can cause long term damage, the medications used are often ones that inhibit cytokine production or function. These work by blocking the receptor sites on cells that bind to a specific cytokine. Overproduction of certain cytokines can lead to disease often involving inflammation, once again showing the interdependence of cytokines and inflammation.