title: Dopamine concentration in blood platelets is elevated in patients with head and neck paragangliomas.
abstract: BACKGROUND
  Plasma 3-methoxytyramine (3-MT), a metabolite of dopamine, is elevated in up to 28% of patients with head and neck paragangliomas (HNPGLs). As free dopamine is incorporated in circulating platelets, we determined dopamine concentration in platelets in patients with a HNPGL.
  
  
  METHODS
  A single center cohort study was performed between 2012 and 2014. Thirty-six patients with a HNPGL were compared to healthy controls (68 for dopamine in platelets and 120 for plasma 3-MT).
  
  
  RESULTS
  Dopamine concentration in platelets was elevated in HNPGL patients compared to healthy controls (median [interquartile ranges] 0.48 [0.32-0.82] pmol/109 platelets vs. 0.31 [0.24-0.47] pmol/109 platelets; p<0.05), whereas plasma 3-MT concentration did not differ between both groups (0.06 [0.06-0.08] nmol/L vs. 0.06 [0.06-0.06] nmol/L; p=0.119). Based on 68 healthy controls, the reference interval for dopamine concentration in platelets was 0.12-0.97 pmol/109 platelets. Six (16.7%) patients with a HNPGL demonstrated an increased dopamine concentration in platelets compared to three (8.3%) patients with an increased plasma 3-MT level (p=0.053). The sensitivity and specificity were 16.7% and 98.5% for platelet dopamine and 8.3% and 97.5% for plasma 3-MT concentration (p=0.37).
  
  
  CONCLUSIONS
  Dopamine concentration in platelets is elevated in patients with a HNPGL compared to healthy subjects, and may be a novel biomarker for dopamine producing paraganglioma.
authors.forename: Thamara E
authors.initials: TE
authors.lastname: Osinga
authors.forename: Anouk N A
authors.initials: AN
authors.lastname: van der Horst-Schrivers
authors.forename: Martijn
authors.initials: M
authors.lastname: van Faassen
authors.forename: Michiel N
authors.initials: MN
authors.lastname: Kerstens
authors.forename: Robin P F
authors.initials: RP
authors.lastname: Dullaart
authors.forename: Marloes A M
authors.initials: MA
authors.lastname: Peters
authors.forename: Bernard F A M
authors.initials: BF
authors.lastname: van der Laan
authors.forename: Geertruida H
authors.initials: GH
authors.lastname: de Bock
authors.forename: Thera P
authors.initials: TP
authors.lastname: Links
authors.forename: Ido P
authors.initials: IP
authors.lastname: Kema
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000737:chemistry*; D015331:Cohort Studies; D004298:Dopamine / Q000097:blood*; D005260:Female; D006258:Head and Neck Neoplasms / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010235:Paraganglioma / Q000097:blood*
chemical_list: D004298:Dopamine