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.

Elevated Serum Levels of Sclerostin are Associated with High Disease Activity and Functional Impairment in Patients with Axial Spondyloarthritis

BACKGROUND

Recent research suggests that biomarkers may be useful in assessing disease activity, structural damage, and response to therapy in axial spondyloarthritis (axSpA). Our study aims at evaluating the relationship between inflammation and bone remodeling markers and variables assessing disease activity and functional disability in patients with axSpA.

METHODS

Serum levels of sclerostin, matrix metalloproteinase-3 (MMP-3), interleukin-17 (IL-17), and IL-23 were measured in 60 patients with axSpA and 20 healthy controls. Disease activity was evaluated using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Functional status was assessed by Bath Ankylosing Spondylitis Function Index (BASFI) and measures of spinal mobility.

RESULTS

Sclerostin levels were more elevated in axSpA patients with high disease activity than in those with low disease activity and in controls. They were significantly correlated with BASFI values (r = 0.29, p = 0.03) and measures of spinal mobility, but not with the classical markers of disease activity (BASDAI, ASDAS, CRP, and ESR). Although both MMP-3 and IL-17 levels were elevated in patients with active disease, they were not correlated with markers of disease activity or with functional disability. The levels of sclerostin, MMP-3, IL-17, and IL-23 were similar in axSpA patients and healthy controls.

CONCLUSIONS

Elevated levels of sclerostin, MMP-3, and IL-17 were observed in axSpA patients with active disease, suggesting their potential role in assessing disease activity. In axSpA patients, sclerostin levels might be equally influenced by inflammation and level of physical activity. Further studies are required to confirm our findings in order to understand their clinical value.