title: A pro-inflammatory glycoprotein biomarker is associated with lower bilirubin in metabolic syndrome.
abstract: OBJECTIVE
  Bilirubin exerts anti-oxidative and anti-inflammatory properties which may beneficially influence the development of cardio-metabolic disorders. A nuclear magnetic resonance (NMR) spectroscopy-based glycoprotein biomarker, designated GlycA, whose signal originates from several glycosylated acute-phase proteins, has been recently developed. We tested whether plasma GlycA is associated with bilirubin in subjects with and without MetS.
  
  
  METHODS
  GlycA (NMR spectroscopy), high sensitivity C-reactive protein (hs-CRP) and bilirubin were measured in 58 fasting subjects with MetS and in 63 subjects without MetS (including 65 subjects with type 2 diabetes mellitus).
  
  
  RESULTS
  GlycA and hs-CRP were higher, coinciding with lower bilirubin in MetS (p<0.01 for each). In all subjects combined, GlycA was strongly correlated with hs-CRP (r=0.631, p<0.001). Age-, sex- and diabetes status-adjusted multivariable linear regression analysis demonstrated that GlycA and hs-CRP were both associated positively with the presence of MetS (β=0.256, p=0.014 and β=0.259, p=0.012, respectively). GlycA and hs-CRP were negatively related to bilirubin (β=-0.258, p=0.007 and β=-0.305, p<0.001, respectively), independent of MetS (p>0.05 for each) and diabetes status (p>0.50 for each).
  
  
  CONCLUSIONS
  GlycA is elevated in MetS, and may represent a quantitative measure of a pro-inflammatory state. Increased levels of glycosylated acute-phase proteins are associated with lower bilirubin in MetS.
authors.affiliation: Department of Endocrinology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. Electronic address: r.p.f.dullaart@int.umcg.nl.
authors.forename: Robin P F
authors.initials: RP
authors.lastname: Dullaart
authors.affiliation: Department of Endocrinology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Eke G
authors.initials: EG
authors.lastname: Gruppen
authors.affiliation: LabCorp, Raleigh, NC, USA.
authors.forename: Margery A
authors.initials: MA
authors.lastname: Connelly
authors.affiliation: Department of Vascular Medicine, University of Groningen and University Medical Center, Groningen, The Netherlands.
authors.forename: Joop D
authors.initials: JD
authors.lastname: Lefrandt
mesh_terms: D000209:Acute-Phase Proteins / Q000378:metabolism; D001663:Bilirubin / Q000097:blood*; D015415:Biomarkers / Q000097:blood* / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000378:metabolism*; D008875:Middle Aged
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D006023:Glycoproteins; D002097:C-Reactive Protein; D001663:Bilirubin
keywords: Bilirubin; Diabetes mellitus; Glycoproteins; High-sensitivity C-reactive protein; Metabolic syndrome