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Aging and Inflammation
By: Peter T. Pugliese, MD
Posted: November 24, 2009, from the December 2009 issue of Skin Inc. magazine.
page 4 of 8
The most common types of cytokines are interleukins, cytokines made by white blood cells for other white blood cells; lymphokines, made by lymphocytes; monokines, made by monocytes; and chemokines, which are cytokines that attract things, usually other cells. The function of cytokines is to regulate cell activity in immunity, inflammation and blood cell production, known as hematopoiesis.
All cytokines are made to order, act at very short distances and are never stored. They bind to specific cytokine receptors on the cell and trigger second messengers in the cell. These second messengers, and there are many of them, relay the cytokine signal to the nucleus and react with the DNA to do something that changes the cells in some manner. Most cytokines are made by T helper cells and macrophages.
Nuclear factor kappa B (NF-κB). Cytokines also activate transcription factors. One specific transcription factor is called NF-κB. When a cell receptor is bonded to a cytokine, it sends a message to biochemicals in the cytoplasm that translate the message, that is, what must then be done with this particular signal. The translation process itself is complicated, but is essentially one of activating the transcription factor to prepare it to enter the nucleus. According to Encyclopedia Britannica, a transcription factor is a “molecule that controls the activity of a gene by determining whether the gene’s deoxyribonucleic acid (DNA) is transcribed into ribonucleic acid (RNA). The enzyme RNA polymerase catalyzes the chemical reactions that synthesize RNA, using the gene’s DNA as a template. Transcription factors control when, where and how efficiently RNA polymerases function.”
NF-κB is an ubiquitous rapid-response transcription factor in cells involved in immune and inflammatory reactions, and exerts its effect by expressing cytokines, chemokines, cell adhesion molecules, growth factors and immunoreceptors.1
Inflammation and the aging process
The aging process may be described in many cases as prolonged inflammation associated with tissue destruction, active inflammation and attempts at healing, processes that are all present and active. Whatever the underlying cause, something initiates the process, and a sustained immune reaction results.