Even
though inflammation is a normal and helpful process that the body uses
to protect itself, long term inflammation can lead to serious disease of
aging. Inflammation is a localized response of the body that is
triggered by microbial invasion or tissue damage. It is a normal
response that the body uses to protect itself and keep infection local
rather than systemic. However, recently there is building evidence
indicating that it has a big role in the aging process.
The
four key characteristics of inflammation are redness, pain, heat and
swelling. Although it is not something we enjoy the body uses
inflammation to prevent a potential infection from spreading to other
parts of the body. Inflammation is localized which means it occurs in
the tissues and not in the blood. It involves chemical messengers of the
body called cytokines that are released by the immune system. Many
cytokines are involved in growth and regulation of immune cells. Some of
these cytokines include tumor necrosis factor- α and interleukin-6.
The
typical inflammatory response is acute (rapid and short onset) and
meant to protect the body from microbial pathogens and promote tissue
repair to return to normal (homeostasis). However, it is chronic long
term inflammation that is tied to the aging process and may even be
linked to diseases such as atherosclerosis, dementia and cancer as well
as skin damage and wrinkles.
The
stages of inflammation are vasodilation, phagocytosis, chemotaxis and
tissue repair. Vasodilation refers to an increase in the diameter of the
blood vessels and an increase in their permeability. Increased
permeability allows the blood proteins and whit blood cells to leak out
of the blood and into the inflamed tissue. It is this response that
begins the symptoms of heat, redness and swelling. Because there is now
more heat, metabolism is increased. This response is caused primarily by
histamine, a protein released from basophils in the local area that is
damaged.
Phagocytosis
is a wonderful word that means ‘cell eating’. Cells that are
transformed into phagocytes actually engulf particles including
bacteria, cellular debris and foreign articles that enter the tissue.
Enzymes in the phagocyte then dissolve this debris. This is a way of
cleaning up an area.
Chemotaxis
refers to the movement or migration of cells, typically phagocytes,
towards the area of inflammation. This occurs because of attractive
factors secreted by bacteria and injured tissues. These white blood
cells squeeze their way through the capillaries into the tissues through
an ameboid like movement called diapedisis. Here is a picture of
diapedesis http://medical-dictionary.thefreedictionary.com/diapedesis