title: Circulating matrix Gla protein is associated with coronary artery calcification and vitamin K status in healthy women.
abstract: Matrix Gla protein (MGP) is a vitamin K-dependent protein and an inhibitor of vascular calcification. Vitamin K is required for the carboxylation of MGP and can thereby reduce calcification. Circulating MGP species with different conformations have been investigated as markers for coronary artery calcification (CAC). In high-risk populations, high total uncarboxylated MGP (t-ucMGP) was associated with decreased CAC, while high non-phosphorylated uncarboxylated MGP (dp-ucMGP) was associated with a poor vitamin K status. This cross-sectional study investigated the association of MGP species with CAC, vitamin K status among 200 healthy women. Circulating dp-ucMGP, t-ucMGP and, non-phosphorylated carboxylated MGP (dp-cMGP) levels were measured by ELISA techniques and Agatston score by multi-detector computed tomography. The ratio of uncarboxylated to carboxylated osteocalcin was used as proxy of vitamin K status. A borderline significant (P=.06) association between higher circulating dp-ucMGP levels and high CAC was observed (β=0.091, 95% CI-0.01; 0.19). In the entire study population, high t-ucMGP levels tended to be associated (P=.09) with lower CAC (β=-0.36, 95% CI:-0.78; 0.06). This association strengthened amongst women with CAC to a significant relation between high t-ucMGP levels and lower CAC (β=-0.55, 95% CI-1.01;-0.10). Dp-cMGP was not associated with CAC. Low vitamin K-status was associated with high dp-ucMGP concentrations (β=0.138, 95% CI 0.09; 0.19) but not with other MGP species. These results show that dp-ucMGP may serve as a biomarker of vitamin K status. Circulating dp-ucMGP and t-ucMGP may serve as markers for the extent of CAC, but these findings need to be confirmed.
authors: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands. G.W.Dalmeijer@umcutrecht.nl
authors: Geertje W
authors: GW
authors: Dalmeijer
authors: Yvonne T
authors: YT
authors: van der Schouw
authors: Cees
authors: C
authors: Vermeer
authors: Elke J
authors: EJ
authors: Magdeleyns
authors: Leon J
authors: LJ
authors: Schurgers
authors: Joline W J
authors: JW
authors: Beulens
mesh_terms: D002114:Calcinosis; D002135:Calcium-Binding Proteins / Q000097:blood*; D003331:Coronary Vessels / Q000473:pathology*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D012016:Reference Values; D014812:Vitamin K / Q000097:blood*; D000097568:Matrix Gla Protein
chemical_list: D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D014812:Vitamin K; D000097568:Matrix Gla Protein