A pro-inflammatory glycoprotein biomarker is associated with lower bilirubin in metabolic syndrome

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.

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).

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).

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.