Role of the Central Immune System in Functional Disorders
Immune activation in the CNS may be considered as a possible physiological basis for the overlap of the different symptoms in functional disorders, including functional bowel disorders.
By: Sylvie Bradesi, Ph.D., Center for Neurovisceral Sciences and Women Health & CURE: Digestive Diseases Research Center, David Geffen School of Medicine at UCLA, Los Angeles and VA Greater Los Angeles Heath Care System, Los Angeles, California
Dr. Bradesi is the recipient of the 2007 IFFGD Research Award for Junior Investigator – Basic Science. Her research has looked at neuroimmune interactions in the spinal cord at the molecular level and the role of this response in chronic pain.
At a Glance
• Functional pain disorders are common; they affect many areas of the body.
• Chronic stress activates certain immune cells (glia) in the spinal cord.
• Immune changes in the spinal cord, even when there is no infection or injury, may play a role in increasing pain sensitivity in the colon.
Summary
Accumulating evidence indicates that immune activation within the central nervous system (CNS) plays a crucial role in the increased pain perception observed in conditions of inflammation or injury in the body. In addition, an increasing number of reports from experimental animal studies show that immune activation in the CNS can occur in response to stress. Combined with increasing reports that chronic stress plays a key role in the worsening or intensity of symptoms in functional gastrointestinal disorders or functional pain disorders, these data provide a conceptual framework supporting a possible role of CNS activation in the development of multiple symptoms in syndromes of functional pain.
Recently, a new concept of activation of immune cells within the CNS, including the brain and the spinal cord, has been proposed as a major factor contributing to the generation and maintenance of chronic pain. Signs of immune activation have been described in certain patients suffering from functional pain disorders (in which they have no signs in the body of inflammation or injury).
In our laboratory, we study the mechanisms of the influence of stress on visceral pain in the colon. In view of our findings, we have recently focused our research efforts to study whether or not chronic pain sensitivity in the colon in response to stress may be linked to activation of the immune system in the CNS.
We propose a new conceptual model, which provides a new basis for drug development for the treatment of chronic functional pain.