23. Biochemistry of inflammation

Inflammation can be caused by many things. Burns, chemical irritants, frostbite, toxins, physical injury or radiation, but the most commonly known cause is infection.

The mechanism of inflammation involved vasodilation, edema, immigration of cells, chemotaxis and phagocytosis.

Many disorders are associated with inflammation, like asthma, autoimmune diseases and inflammatory bowel diseases.

There are many differences between acute and chronic inflammation. The most important is the timescale on which it happens. Chronic can be life-long, while acute doesn’t last for many days.

If a local infection is large enough, it will cause a systemic inflammation as part of the acute phase reaction. A severe infection can cause sepsis or septic shock, which may lead to death. There is no good universal therapy against sepsis, noe must treat the underlying condition.

Some cells have something called pattern recognition receptors (PRRs), which recognize molecules found on pathogens called pathogen associated molecular patterns (PAMPs). However, these receptors can also be activated in response to proteins that are found inside cells, if the cell is injured or killed by necrosis. These proteins are called damage associated molecular patterns (DAMPs) and will cause a similar immune reaction as a pathogen infection would.

Examples of PAMPs are teichoic acid, peptidoglycan and lipopolysaccharide. The first two are found on Gram-positive bacteria, while the last is found on Gram-negative bacteria.