New animal research in the February 18 issue of The Journal of Neuroscience may indicate how certain diseases make people feel so tired and listless. Although the brain is usually isolated from the immune system, the study suggests that certain behavioral changes suffered by those with chronic inflammatory diseases are caused by the infiltration of immune cells into the brain. The findings suggest possible new treatment avenues to improve patients' quality of life.
Chronic inflammatory diseases like rheumatoid arthritis, inflammatory bowel disease, psoriasis, and liver disease cause "sickness behaviors," including fatigue, malaise, and loss of social interest. However, it has been unclear how inflammation in other organs in the body can impact the brain and behavior.
The researchers found that in mice with inflamed livers, white blood cells called monocytes infiltrated the brain. These findings support previous research demonstrating the presence of immune cells in the brain following organ inflammation, challenging the long-held belief that the blood-brain barrier prevents immune cells from accessing the brain.
The researchers identified chemicals that encouraged immune system monocytes to enter the brain.
"Using an experimental model of liver inflammation, our group has demonstrated for the first time the existence of a novel communication pathway between the inflamed liver and the brain," said the study's senior author Mark Swain, MD, Professor of Medicine at the University of Calgary.
Swain and his colleagues found that liver inflammation triggered brain cells called microglia to produce CCL2, a chemical that attracts monocytes. When the researchers blocked CCL2 signaling, monocytes did not enter the brain despite ongoing inflammation in the liver.
Liver inflammation also stimulated cells in the blood to make an immune chemical (TNFα). When the researchers blocked the signaling of this immune chemical, microglia produced less CCL2, and monocytes stayed out of the brain.
This is usable information because there are lots of ways to decrease the level of inflammation in your body. You can eat tart cherries, pistachios, grapes, vegetables, and omega 3 fatty acids from fish to cut down in your body's level of inflammation. Exercise helps too. Feeling fatigued? You might need a better diet and exercise.
|Share |||Randall Parker, 2009 February 17 11:49 PM Aging Mechanisms|