title: Evidence for an altered tryptophan metabolism in fibromyalgia.
abstract: Fibromyalgia (FM) is a prevalent syndrome with chronic pain and a hypothesized underlying disturbance of the tryptophan (TRP) metabolism. We performed a tryptophan depletion (TD) test in 17 FM patients and 17 controls. TRP, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), and interleukin-6 (IL-6) were measured. Additionally pain perception was monitored in the FM patients. FM patients and controls exhibited a decrease of TRP and KYN during TD. 5-HIAA levels also decreased in all controls and in 11 FM patients, but showed a marked increase in 6 FM patients. IL-6 significantly increased during TD in the patients, but not in the controls. Pain perception was not affected in the FM patients. These data demonstrate an altered TRP metabolism in a subgroup of FM patients, where the TD seems to activate 5-HT metabolism. Our findings may have diagnostic as well as therapeutic implications in the field of fibromyalgia.
authors.affiliation: Psychiatric Hospital, University of Munich, D-80336, Munich, Germany.
authors.forename: M J
authors.initials: MJ
authors.lastname: Schwarz
authors.forename: M
authors.initials: M
authors.lastname: Offenbaecher
authors.forename: A
authors.initials: A
authors.lastname: Neumeister
authors.forename: T
authors.initials: T
authors.lastname: Ewert
authors.forename: M
authors.initials: M
authors.lastname: Willeit
authors.forename: N
authors.initials: N
authors.lastname: Praschak-Rieder
authors.forename: J
authors.initials: J
authors.lastname: Zach
authors.forename: M
authors.initials: M
authors.lastname: Zacherl
authors.forename: K
authors.initials: K
authors.lastname: Lossau
authors.forename: R
authors.initials: R
authors.lastname: Weisser
authors.forename: G
authors.initials: G
authors.lastname: Stucki
authors.forename: M
authors.initials: M
authors.lastname: Ackenheil
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005356:Fibromyalgia / Q000378:metabolism*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000097:blood / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D007737:Kynurenine / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D010146:Pain / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D014364:Tryptophan / Q000097:blood / Q000172:deficiency / Q000378:metabolism*
chemical_list: D015850:Interleukin-6; D012701:Serotonin; D007737:Kynurenine; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan