title: Experimental evaluation of an altered tryptophan metabolism in fibromyalgia.
abstract: Fibromyalgia (FM) is a prevalent syndrome with chronic pain and a hypothesised 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 and IL-6 production. Our findings may have diagnostic as well as therapeutic implications in the field of fibromyalgia.
authors.affiliation: Psychiatric Hospital, University of Munich, Nussbaumstr. 7, D - 80336 Munich, Germany. mschwarz@psy.med.uni-muenchen.de
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Schwarz
authors.forename: Martin
authors.initials: M
authors.lastname: Offenbaecher
authors.forename: Alexander
authors.initials: A
authors.lastname: Neumeister
authors.forename: Manfred
authors.initials: M
authors.lastname: Ackenheil
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005356:Fibromyalgia / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D007737:Kynurenine / Q000378:metabolism; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology; D012701:Serotonin / Q000378:metabolism; D014364:Tryptophan / Q000172:deficiency / Q000378:metabolism*
chemical_list: D015850:Interleukin-6; D012701:Serotonin; D007737:Kynurenine; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan