The circulating inactive form of matrix gla protein is a surrogate marker for vascular calcification in chronic kidney disease: a preliminary report.

Abstract

BACKGROUND AND OBJECTIVES:

Vitamin K-dependent matrix Gla protein (MGP) acts as a calcification inhibitor in vitro and in vivo. The present study was performed to (1) determine plasma levels of the inactive, dephosphorylated, uncarboxylated MGP (dp-ucMGP) in a cohort of patients at different stages of chronic kidney disease (CKD) and (2) evaluate the association between dp-ucMGP levels on one hand and aortic calcification and mortality on the other.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:

107 patients (67 +/- 13 years; 60% male; 32% at CKD stages 2 to 3, 31% at stages 4 to 5, 37% at stage 5D) were assayed for dp-ucMGP and underwent multislice spiral computed tomography scans to quantify aortic calcification at baseline. They were prospectively monitored for mortality.

RESULTS:

Plasma dp-ucMGP levels augmented progressively with CKD stage, with a significant difference from CKD stage 4. CKD stage, hemoglobin, age, and coumarin use were independently associated with plasma dp-ucMGP levels. Furthermore, plasma dp-ucMGP and age were positively and independently associated with the aortic calcification score. During follow-up (802 +/- 311 days), 34 patients died (20 from cardiovascular events). In a crude analysis, [plasma dp-ucMGP] > 921 pM was associated with overall mortality; this association was lost after adjusting for both age and the calculated propensity score.

CONCLUSIONS:

Plasma dp-ucMGP increased progressively in a CKD setting and was associated with the severity of aortic calcification. Plasma dp-ucMGP could thus be a surrogate marker for vascular calcification in CKD.

• Authors: Leon J Schurgers, Daniela V Barreto, Fellype C Barreto, Sophie Liabeuf, Cédric Renard, Elke J Magdeleyns, Cees Vermeer, Gabriel Choukroun, Ziad A Massy
• Journal: Clinical journal of the American Society of Nephrology : CJASN (Clin J Am Soc Nephrol) Vol. 5 Issue 4 Pg. 568-75 (Apr 2010) ISSN: 1555-905X [Electronic] United States
• PMID: 20133489 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Calcium-Binding Proteins
• Extracellular Matrix Proteins
• matrix Gla protein

Topics

• Aged
• Aged, 80 and over
• Aortic Diseases (blood, diagnostic imaging, mortality)
• Aortography (methods)
• Biomarkers (blood)
• Calcinosis (blood, diagnostic imaging, mortality)
• Calcium-Binding Proteins (blood)
• Chi-Square Distribution
• Chronic Disease
• Extracellular Matrix Proteins (blood)
• Female
• Humans
• Kaplan-Meier Estimate
• Kidney Diseases (blood, diagnostic imaging, mortality)
• Linear Models
• Male
• Middle Aged
• Pilot Projects
• Predictive Value of Tests
• Prognosis
• Proportional Hazards Models
• Prospective Studies
• Risk Assessment
• Risk Factors
• Severity of Illness Index
• Time Factors
• Tomography, Spiral Computed
• Up-Regulation