Brain-Immune Interactions in Health and Disease
Implications for Susceptibility to Arthritis and Infectious Disease
Esther M. Sternberg
National Institute of Mental Health
About the Lecture
This lecture will outline scientific advances in understanding the communication networks between the nervous and immune systems: the scientific underpinning of the popular mind-body interaction. The idea that the mind and negative or positive states of mind, such as psychological stress or well-being, can influence health and disease has been in the popular culture for thousands of years. Recent scientific advances prove that there is a molecular, cellular, neuroanatomical and neurohormonal basis for communication between the brain and the immune system. Through such communications the nervous and immune systems interact and modify each other's functions. Interruptions of this interaction, on a genetic, drug-induced or surgical basis, lead to enhanced susceptibility to inflammatory disease. Over-activity of the neuroendocrine component of these interactions, such as occurs during stress, is associated with exacerbations of, or increased susceptibility to, infectious disease. On the basis of such findings, new drug treatments are currently being developed, such as the use of anti-inflammatory drugs in Alzheimer's, anti-stress hormone drugs in arthritis or neurotransmitter related drugs for improving immune responses associated with aging.
About the Speaker
Esther Sternberg received her M.D. degree and trained in Rheumatology at McGill University, Montreal, Canada. She did post-doctoral training at Washington University, Barnes Hospital, St. Louis, MO, in the Division of Allergy and Immunology. She was subsequently a Howard Hughes Associate and Instructor in Medicine at Washington University and Barnes Hospital, before joining the National Institutes of Health in 1986. She is currently director of the Integrative Neural-Immune Program and chief of the Section on Neuroendocrine Immunology and Behavior, National Institute of Mental Health, National Institutes of Health. She is the author of The Balance Within: The Science Connecting Emotions and Health (W.H. Freeman and Company) .
Find her book at Amazon.com:
The Balance Within: The Science Connecting Health and Emotions
President Spargo called the 2121st meeting to order at 8:15 p.m. on October 20, 2000. The Recording Secretary read the minutes of the 2120th meeting and they were approved with emendations.
The speaker for the evening was Esther M. Sternberg. The title of her presentation was “Brain-Immune Interactions in Health and Disease: Implications for Susceptibility to Arthritis and Infectious Disease”.
In her book The Balance Within: The Science Connecting Emotions and Health, Ms. Sternberg addresses the questions, “Can stress make you sick? Can believing make you well?”
The belief that negative or positive states of mind, such as psychological stress or well-being, could influence health and the course of disease had been widely held by many cultures for thousands of years. However, scientific culture since the Greeks since had generally discounted these beliefs. Now, we realize that some of these ideas, at least, should not be summarily rejected. Recent studies indicate they may have a neurohormonal, neuroanatomical, cellular and molecular basis in the complex communication network between the nervous and immune systems. Two classes of hormones, cytokines and interleukins, have been found to be responsible for many symptoms of illness such as mental depression and loss of appetite and energy. In the brain, these same hormones have been found to affect nerve cell death and survival. Some forms of neurodegeneration are caused by these chemicals, and treatments which block cytokine and interleukin activity in the brain have been used in the treatment and prevention of brain damage in stroke, Alzheimer's disease, multiple sclerosis and other brain traumas.
The stress response of organisms has a survival benefit. The body's “fight or flight” response to stress was elaborated by Hans Selye. He found that this response is mediated by the hormone adrenalin. It was also known that sometimes the memory of a stress can be as damaging to health as the original challenge, indicative of mind-body interactions other than nerve conduction.
The sequence of hormonal actions caused by stress begins in the brain where the hypothalamus produces corticotropin releasing hormone (CRH); this hormone acts on the pituitary to produce adrenocorticotropic hormone (ACTH); and this acts on the adrenal glands to produce glucocorticosteroids (or glucocorticoids) and adrenaline. Glucocorticosteroids released into the blood act on the immune system to depress the immune response. Interleukins and cytokines produced in the immune response have been found to stimulate CRH release, and so initiate the sequence of actions that limit the immune response through feedback inhibition. Some of the results of chronic stress suppression of the immune response are prolonged wound healing, increased severity and morbidity of viral infections, and lower response to vaccination. Thus, over-activity of the neuroendocrine system, especially the hypothalamus, the pituitary and the adrenal glands such as occurs during stress, is associated with exacerbation of, or increased susceptibility to, infectious diseases.
The endorphins are peptide hormones released by the adrenal glands and other tissues that act powerfully on the nervous system to reduce stress. They are also known to affect the immune response, but the mechanism is not understood. So far, there are 15 known genetic linkages for the hormonal stress response. Overall, the factors controlling hormonal stress response are thought to be about 35% genetic and 65% environmental. Surgical or pharmacological actions that blunt hormonal stress also lead to enhanced susceptibility to inflammatory disease, increasing inflammation, arthritis, dermatitis, and lupus.
How can bad stress be turned to good advantage? Generally, those effects which restore a sense of control lower the demands of stress. Some of the mechanisms that have proven effective are training and rehearsal, biofeedback, stress reduction counseling, meditation and psychotherapy. Different people, of course, respond in different ways and under different situations to these therapies. Ironically, it is chronic caregivers who typically experience the most severe chronic stress.
Can believing make you well? Belief is difficult to measure quantitatively, hampering scientific study. Some workers attempted to study the effects of belief on pain and stress experienced in Vietnam combat. Belief in self, comrades, family, country, and religion were found to be positive factors in relieving the symptoms of stress and surviving trauma. In medical studies, it has been found that 30 to 90% of the effect of any cure can be attributed to a placebo effect; the belief that the cure will work. At least some of this placebo effect may be attributed to the real effect of conditioning the immune system. One example involves the suppression of the immune system with cyclophosphamide paired with sweeteners. When the compound is removed, the sweeteners alone continue to produce the same immunosuppressive effects.
Using these findings on how the nervous and immune systems interact and modify each other's functions, new drug treatments are being developed, such as anti-inflammatory drugs in Alzheimer's, anti-stress drugs in arthritis, and neurotransmitter related drugs for improving immune response which declines with aging.
Ms. Sternberg kindly answered questions from the floor. President Spargo thanked Ms. Sternberg for the society, and welcomed her to its membership. Program Chair Bill Saalbach spoke briefly on recruiting members and speakers. The President made a special announcement concerning the health of former President Eloise Agger. He then made the announcements about the next meeting, parking, and refreshments, and adjourned the 2121st meeting to the social hour at 9:40 p.m.
John S. Garavelli