Cytokines are molecules of protein that help regulate the body’s immune response to infections and trauma. Some promote the healing of wounds, while others, such as proinflammatory cytokines, increase inflammation and can cause diseases to progress. Interleukin and tumor necrosis factor are substances in the immune system that promote inflammation. If they are injected, the result is usually fever and inflammation throughout the body. Some researchers believe the regulation of pro- and anti-inflammatory cytokines in the body might be how the immune system is kept in check.
Typically released when cells are under stress, cytokines are proteins that don’t have a defined structure. They are sometimes compared to hormones but are not just made by specific cells, but are synthesized by almost all types. Contact with a foreign material, extreme heat, and exposure to ultraviolet light can increase production. A few substances can suppress genes that code for proinflammatory cytokines, such as some types of interleukin and interferon. Genes of those sometimes contain codes for enzymes involved in platelet activation and production of nitric oxide.
Proinflammatory cytokines also include chemokines that can let immune cells called leukocytes get from the blood into infected tissues. Other such cytokines activate molecules that can attach to the blood vessel walls to let immune cells pass through. In general, proinflammatory cytokines start off a cascading immune response that starts with an injury, infection, oxygen starvation, or exposure to toxic substances.
Some researchers believe that the balance of cytokines directly affects how someone will recover from a disease. Genes that help express anti- or proinflammatory cytokines can also impact a person’s susceptibility to a disease, such as arthritis or chronic inflammation of the bowels. The cytokines themselves trigger activity by linking to a receptor on the cell surface. A direct connection can affect the regulation of genes inside the cell and the production of receptors that accept certain molecules.
Proinflammatory cytokines are often involved in wound repair processes, such as stimulating skin cells like keratinocytes and collagen producing cells called fibroblasts. They can also break down proteins while regulating the response of the immune system at the same time. Blocking the regulation of certain proinflammatory cytokines can affect the scarring of wounds, and has even led to death in many laboratory animals. Since production occurs in a cascade along with other processes, an imbalance can lead to many diseases and conditions involving inflammation and problems with wound healing.