Melatonin is a hormone which is secreted by the pineal gland of the brain. It regulates the "sleep-wake" cycle, also known as the "internal clock," which lets the body know when it is time to sleep and when it is time to awaken. Some scientists have investigated whether melatonin also promotes the development of autoimmune diseases, like rheumatoid arthritis, due to its effect on the white blood cells.
Rheumatoid Arthritis
Rheumatoid arthritis affects an estimated 1 percent of adults throughout the world, according to James O'Dell, M.D., vice chairman of the Department of Internal Medicine at the University of Nebraska Medical Center in "Current Rheumatology Diagnosis & Treatment." It is a chronic or long-term arthritis which affects women three times more than men. Physicians are not yet sure what causes it, but consider it to be an autoimmune disease where the immune system becomes confused and attacks healthy tissue instead of attacking foreign substances.
Rheumatoid Factor
Antibodies are proteins which are made by the immune system to destroy foreign substances. More than 66 percent of the people with rheumatoid arthritis have antibodies referred to as the rheumatoid factor, per Peter Lipsky, M.D., chief of the Autoimmunity Branch of the National Institutes of Health in "Harrison's Principles of Internal Medicine." For someone to be diagnosed with rheumatoid arthritis, he usually must have rheumatoid factor, arthritis in both hands and three other joints for at least six weeks, with joints that are stiff in the morning.
Melatonin and Rheumatoid Arthritis
In the October 2004 issue of the "Journal of Neuroimmunity," George Maestroni writes that melatonin may encourage the development of autoimmune disease, including rheumatoid arthritis, because it acts on some of the white blood cells involved in fighting foreign substances. In addition, he found that people with rheumatoid arthritis have an increased amount of melatonin in their bloodstream. In trying to determine the role of melatonin, his research group found that when rats had their pineal gland removed, they had less inflammation. The pineal gland secretes melatonin.
Superoxide
Since the publication of October 2004, other scientists have not found that melatonin plays a disease-promoting role in rheumatoid arthritis. However, some research has shown that besides rheumatoid factor antibodies, a substance called superoxide may have a role. Superoxide is a free oxygen radical. It is harmful to the tissues and like rheumatoid factor, it appears in high amounts in the fluid of arthritic joints, writes Valery Afonso in an article in the July 2007 issue of "Joint Bone Spine."
References
- "Current Rheumatology Diagnosis & Treatment"; John Imboden, M.D., David Hellmann, M.D., John Stone, M.D.; 2007
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- "Joint Bone Spine"; Reactive oxygen species and superoxide dismutases: Role in joint diseases; Valéry Afonso et al.; July 2007
- "Journal of Neuroimmunology"; Does melatonin play a disease-promoting role in rheumatoid arthritis?; Georges Maestroni, Daniel Cardinali et al; 2005
