Inflammation and Chronic Pelvic Pain: A Biological Trigger for Depression in Women?

Abstract

Depression is often associated with local and/or systemic diseases. Chronic inflammation, pain and depression are a clinical triad increasingly recognized as co-morbid. Peripheral and central inflammation can alter neuronal activity, thereby contributing to the psych emotional and somatic symptoms of depression. Preliminary evidence suggests that mast cells direct the immune pathways mediating this triad. Chronic pelvic pain in women could be a paradigm of the triad, and of considerable clinical relevance. Mast cells are immune cells which contribute to and modulate inflammation and immunity. Upon stimulation mast cells release an array of mediators, cytokines, and growth factors to orchestrate an inflammatory response. These mediators can directly initiate tissue responses on resident cells, and may also regulate the activity of other immune cell functions, including central nervous system immune cells like microglia. Mast cell mediators can interact also with neurons, either alone or in concert with other immune cells. New evidence supports the involvement of peripheral and central mast cells in the development of pain processes, in the transition from acute, nociceptive to chronic and neuropathic pain and in the depressive states associated with them. A significant increase of pro-inflammatory cytokines is evident in depression associated with chronic diseases. Marked increases of tissue mast cells and pro-inflammatory cytokines have been documented in disorders associated with chronic pelvic pain presenting as well with significant affective comorbidities (anxiety and depression). Mast cells could be thus considered as a target of therapeutic approaches which aim to reduce inflammation and the chronicization of pain. The present review analyzes current evidence on co-morbidity between depression with peripheral and central inflammation associated with chronic pelvic pain in women. The analysis will briefly focus on key mechanisms of inflammation and role of mast cells as a common denominator of depression and chronic pain. The goal is to offer mental health professionals a biologicallyoriented contribution in the pathophysiologic reading of co-morbidities between depression and chronic pelvic pain in women. Results underline the increasing evidence supporting a role of inflammatory pathways/mechanisms, orchestrated by activated mast cells, as common denominators contributing to co-morbidity between depression and chronic pelvic pain in women.