title: Tryptophan metabolism in post-withdrawal alcohol-dependent patients.
abstract: OBJECTIVE
  The aim of the study was to investigate the parameters of tryptophan and phenylalanine metabolism and their associations to immune system activation and to behavioural symptoms during medium-term withdrawal (4-12 weeks of abstinence) in alcohol-dependent patients.
  
  
  METHODS
  Biochemical assays and clinical assessments at the beginning of treatment (fourth week of alcohol abstinence in average) and prior to the discharge after 8 weeks of treatment.
  
  
  RESULTS
  Kynurenine to tryptophan ratio (Kyn/Trp) slightly correlated with neopterin levels in early post-withdrawal period (Week 4 of abstinence) but this association disappeared after 12 weeks of abstinence. Phenylalanine and tyrosine concentrations as well as phenylalanine to tyrosine ratio (Phe/Tyr) decreased between Weeks 4 and 12 of abstinence. Kynurenine and Kyn/Trp increased significantly at 12th week of abstinence when compared with the beginning of the study (Week 4 of abstinence). At Week 12, Kyn/Trp significantly correlated with such behavioural symptoms as fatigue, irritability and sleep disturbances.
  
  
  CONCLUSIONS
  Tryptophan breakdown in early stages may be influenced by the increased activity of indoleamine 2,3-dioxygenase but the increase of Kyn/Trp between Weeks 4 and 12 of abstinence seems to be independent of immune changes and correlates with behavioural symptoms in later stages of the post-withdrawal course. A possible role of kynurenine metabolites in mediation of the increased stress sensibility in post-withdrawal alcohol-dependent patients is discussed.
authors.affiliation: Corresponding author: Department of Psychiatry and Psychotherapy, Medical University Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria. s.mechtcheriakov@i-med.ac.at.
authors.forename: Gabriele V
authors.initials: GV
authors.lastname: Gleissenthall
authors.forename: Simon
authors.initials: S
authors.lastname: Geisler
authors.forename: Peter
authors.initials: P
authors.lastname: Malik
authors.forename: Georg
authors.initials: G
authors.lastname: Kemmler
authors.forename: Hannah
authors.initials: H
authors.lastname: Benicke
authors.forename: Dietmar
authors.initials: D
authors.lastname: Fuchs
authors.forename: Sergei
authors.initials: S
authors.lastname: Mechtcheriakov
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000097:blood* / Q000378:metabolism; D005221:Fatigue / Q000097:blood / Q000150:complications; D005260:Female; D006801:Humans; D007107:Immune System; D007508:Irritable Mood; D007737:Kynurenine / Q000097:blood; D008297:Male; D008875:Middle Aged; D019798:Neopterin / Q000097:blood; D010649:Phenylalanine / Q000097:blood; D012893:Sleep Wake Disorders / Q000097:blood / Q000150:complications; D013375:Substance Withdrawal Syndrome / Q000097:blood* / Q000378:metabolism; D013997:Time Factors; D014364:Tryptophan / Q000097:blood* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D007737:Kynurenine; D010649:Phenylalanine; D019798:Neopterin; D014364:Tryptophan