Central Pain Sensitization, COMT Val158Met Polymorphism, and Emotional Factors in Fibromyalgia

作者：Desmeules Jules^*; Chabert Jocelyne; Rebsamen Michela; Rapiti Elisabetta; Piguet Valerie; Besson Marie; Dayer Pierre; Cedraschi Christine

来源：Journal of Pain, 2014, 15(2): 129-135.

DOI：10.1016/j.jpain.2013.10.004

• Fibromyalgia
• catechol-O-methyl-transferase polymorphism
• central sensitization
• spinal nociceptive flexion reflex
• psychological distress

Neurobiological evidence points to altered central nervous system processing of nociceptive stimuli in fibromyalgia. Enzymes like catechol-O-methyl-transferase (COMT) are involved in the elimination of catecholamines playing a possible role in central sensitization and pain. We used quantitative sensory testing to evidence central sensitization in fibromyalgia patients and test whether COMTVal158Met polymorphism, associated with a reduction in enzyme activity, plays a role in sensitized patients. Pain evaluation and quantitative sensory testing were performed including the spinal nociceptive flexion reflex, a physiologic correlate for the evaluation of central nociceptive pathways. Quality of life and distress questionnaires were used. A total of 137 fibromyalgia patients were assessed and compared to 99 matched controls. Central sensitization (nociceptive flexion reflex <27 mA) was present in 95/134 (71%) patients. Among them, COMT p.Val158Met polymorphism displayed a significant linear "genotype effect" (P = .033), with the Met/Met (mean = 17.8 +/- 4.8 mA) and Val/Val (mean = 21.4 +/- 4.6 mA) subgroups at the opposite ends of the nociceptive flexion reflex threshold (Met/Met vs Val/Val P = .015) and the Val/Met subgroup (mean = 19 +/- 4.9 mA) in between (Val/Met vs Val/Val P = .041). Spontaneous moderate to severe pain was more likely to be associated with COMT Met/Met genotype. Patients showed important emotional distress compared to controls. In sensitized patients, the COMT Met/Met subgroup showed systematically-though not significantly-worse scores for all psychological variables.
Perspective: The association between COMT p.Val158Met polymorphism and central sensitization in fibromyalgia is essential as it refers to the severity of central sensitization and may be a risk factor for treatment outcome.

• 出版日期2014-2