Serum total matrix Gla protein: Reference interval in healthy adults and variations in patients with vascular and osteoarticular diseases.

Background: Matrix Gla protein (MGP) species are inhibitors of ectopic calcification in vascular diseases (VD) and osteoarticular diseases (OD). Among the MGP assays, we aimed to establish the reference interval for serum total MGP (tMGP) in healthy adults, the variation in patients with VD and OD and the associations with common cardiovascular risk factors.

Methods: We enrolled n = 124 healthy subjects and n = 95 patients with VD and OD in a small cross-sectional study. Serum high sensitivity C-reactive protein (hs-CRP), tMGP, glucose and lipid profile was measured.

Results: We established the reference interval for tMGP as 6-108 μg/L in healthy adults, the population under 40 having higher tMGP levels than those over 40 (61 ± 28, 51 ± 22 μg/L, p < 0.05). In healthy participants, tMGP was associated with smoking (β = 0.303, p = 0.001), age under 40 (β = -0.201, p = 0.032) and marginally with hs-CRP (β = -0.165, p = 0.08). In multivariate regression models, the association between smoking and tMGP was preserved even after adjusting for age under 40 and hs-CRP (β = 0.267, p = 0.005). The healthy population over 40 had lower tMGP levels than patients with OD and VD (51 ± 22, 90 ± 26, 106 ± 30 μg/L, p < 0.001).

Conclusions: Higher tMGP levels could identify patients with VD and OD, being also associated with smoking in healthy adults.