What are the roles of oxidative stress and pro-inflammatory cytokines in fibromyalgia?

Abstract

Fibromyalgia (FM) is a common disorder of unclear aetiology, characterized by chronic widespread pain and painful tender points (body pressure points). Several researchers suggest that elevated levels of the pronociceptive substance substance P enhance pain experience (sensitization of ascending pain pathways). FM is often accompanied by several non-specific symptoms including fatigue, stiffness, disordered sleep, cognitive dysfunction, dysesthesia, psychological distress, headaches, and poor balance. These non-specific symptoms are also observed in ‘sickness behavior’ which is induced by infectious and inflammatory processes, characterized by cytokines. A literary search for cytokines in FM patients suggested several upregulated cytokine levels in FM patients, compared with controls. Furthermore, diseases that show overlap with FM are characterized by enhanced oxidative stress levels. Another literary search regarding oxidative stress in FM patients suggested upregulated oxidative stress levels in FM patients, compared with controls. Eventually, this thesis hypothesized that oxidative stress might be responsible for increased substance P levels via cytokine generation, resulting in elevated pain experience. To place this hypothesis in a broad perspective, the physiological effect of several associated co-morbidities (e.g. diabetes) have been analyzed.