title: Inverse association between serum selenium concentrations and parameters of immune activation in patients with cardiac disorders.
abstract: BACKGROUND
  As a component of the enzyme glutathione peroxidase, the essential trace element selenium contributes to the reduction of peroxides. Disturbed selenium availability may relate to an activated immune response. In humans, immune activation is reflected by increased neopterin production and accelerated tryptophan degradation, expressed as the kynurenine to tryptophan ratio (kyn/trp). Th1-type cytokine interferon-gamma induces both these immunobiological events in human macrophages and they are often activated in patients with cardiac disorders. The aim of this study was to determine the relationship between serum selenium concentrations and neopterin production and tryptophan degradation in patients with cardiac disorders.
  
  
  METHODS
  In 56 patients (28 females) with cardiac disorders, serum selenium concentrations were determined by graphite-furnace atomic absorption spectrometry. Serum neopterin concentration was measured by ELISA and tryptophan degradation was examined by HPLC.
  
  
  RESULTS
  Selenium concentrations were in the range 0.41-1.90 micromol/L (median 1.02) and were well within the local normal range. Approximately two-thirds of patients presented with higher neopterin concentrations (median 16.4 nmol/L) and tryptophan degradation (median 57 micromol/mmol kyn/trp). There was an inverse correlation between serum selenium and kyn/trp (Spearman's rank correlation, r(s)=-0.431; p<0.001) and neopterin concentrations (r(s)=-0.300; p<0.05). Neopterin concentrations correlated strongly with kyn/trp (r(s)=0.712; p<0.0001).
  
  
  CONCLUSIONS
  A higher degree of tryptophan degradation and of neopterin production in patients with cardiac disorders coincides with lower, albeit still normal, serum selenium concentrations. Data show that in these patients immune activation is associated with lower serum selenium concentrations.
authors.affiliation: Division of Biological Chemistry, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Murr
authors.forename: Heribert
authors.initials: H
authors.lastname: Talasz
authors.forename: Erika
authors.initials: E
authors.lastname: Artner-Dworzak
authors.forename: Katharina
authors.initials: K
authors.lastname: Schroecksnadel
authors.forename: Michael
authors.initials: M
authors.lastname: Fiegl
authors.forename: Dietmar
authors.initials: D
authors.lastname: Fuchs
authors.forename: Hubert A
authors.initials: HA
authors.lastname: Denz
mesh_terms: D000368:Aged; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006331:Heart Diseases / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007107:Immune System; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D019798:Neopterin / Q000378:metabolism*; D018384:Oxidative Stress; D015203:Reproducibility of Results; D012643:Selenium / Q000097:blood* / Q000378:metabolism* / Q000494:pharmacology; D014364:Tryptophan / Q000737:chemistry
chemical_list: D019798:Neopterin; D014364:Tryptophan; D012643:Selenium