CHAPTER 20 Brain Inflammation
INFLAMMATION IS THE BODY’S REACTION to infection or injury, causing symptoms of pain, redness, swelling, and warmth. Medications like acetylsalicylic acid (aspirin) suppress the inflammatory response. To better understand how anti-inflammatory compounds can help prevent memory loss, you need to have some basic knowledge about the workings of the immune system, which is responsible for the process of inflammation.
The Immune System
There are two main types of immunity: cell-mediated and humoral. Cell-mediated immunity relies on specialized cells in the body to isolate, surround, and destroy the offender. The white blood cells are the generals in charge of this defense department. They roam through the bloodstream, attacking and destroying all infiltrators and spies: bacteria and viruses, toxins and allergens. If too many white blood cells get bogged down dealing with invaders, extra reinforcements pour out of the bone marrow into the blood to fight the battle.
The second type of immunity, called humoral, is the immune system’s antibody response to a foreign substance (antigen). The antibody is a protein that forms a perfect physical and chemical fit to the antigen molecule, and thus neutralizes it. This antibody response can go haywire and produce allergies, hay fever, and asthma. The body has the capacity to produce new antibodies, or antidotes, to thousands of different compounds or antigens, like a chemical factory that can change the substance it produces at will. Occasionally, a hyperactive immune system can mistakenly attack the body’s own tissues, as happens in rheumatoid arthritis and lupus. On the flip side, a weak
immune system that does not destroy wayward cancerous cells can lead to malignant tumor formation, as occurs in AIDS.
Inflammation in the Alzheimer’s Brain
Within the brain, the immune system interacts closely with nerve cells in several regions and is triggered in a variety of ways. The complement pathway (a sequence of enzymes/proteins) plays an important role in the immune response, and an overactive complement response can damage different areas of the brain. In patients with Alzheimer’s disease, complement activation can trigger the formation of amyloid protein that collects in clumps to make up the pathologic amyloid plaques. Researchers are now studying anti-inflammatory agents that can block or inactivate complement in the treatment of not only Alzheimer’s disease, but also mild to moderate memory loss during the
aging process.
Taken From: The Memory Program How to Prevent Memory Loss
and Enhance Memory Power
