Inactive Matrix Gla Protein, Arterial Stiffness, and Endothelia Function in African American Hemodialysis Patients

Mary Ellen Fain, Gaston K. Kapuku, William D. Paulson, Celestine F. Williams, Anas Raed, Yanbin Dong, Marjo H. J. Knapen, Cees Vermeer, Norman K. Pollock*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    20 Citations (Web of Science)

    Abstract

    BACKGROUND Matrix Gla protein (MGP) is a vascular calcification inhibitor dependent upon vitamin K for activation. Evidence suggests that elevated plasma inactive MGP levels (desphospho-uncarboxylated MGP, dp-ucMGP; indicating poorer vascular vitamin K status) are associated with greater cardiovascular disease (CVD) risk. Despite African Americans experiencing highest rates of kidney failure and CVD events, relationships between dp-ucMGP and CVD risk markers have not been examined in this population. We investigated vascular vitamin K status (via plasma dp-ucMGP) between African American hemodialysis (HD) patients and healthy controls, and the associations of dp-ucMGP with arterial stiffness and endothelial function in HD patients only. METHODS In 37 African American HD patients and 37 age- and race-matched controls, plasma dp-ucMGP was measured by enzyme immunoassay as a marker of vascular vitamin K status. Carotid-femoral pulse wave velocity (PWV; arterial stiffness measurement) and brachial artery flow-mediated dilation (FMD; endothelial function measurement) were assessed by applanation tonometry and ultrasound, respectively, in HD patients only. RESULTS Mean dp-ucMGP levels were 5.6 times higher in HD patients vs. controls (2,139 +/- 1,102 vs. 382 +/- 181 pmol/l, P < 0.01). Multiple linear regression, adjusting for age, sex, dialysis vintage, diabetes mellitus, CVD history, body mass index, and blood pressure, revealed that dp-ucMGP was independently related to PWV (standardized beta = 0.49) and FMD (standardized beta = -0.53) (both P < 0.01). CONCLUSIONS Our data suggest that the higher plasma dp-ucMGP concentrations found in African American HD patients may be associated with greater arterial stiffness and endothelial dysfunction.
    Original languageEnglish
    Pages (from-to)735-741
    Number of pages7
    JournalAmerican Journal of Hypertension
    Volume31
    Issue number6
    DOIs
    Publication statusPublished - 1 Jun 2018

    Keywords

    • African American
    • arterial stiffness
    • blood pressure
    • chronic kidney disease
    • endothelial function
    • hypertension
    • vitamin K
    • VITAMIN-K STATUS
    • CHRONIC KIDNEY-DISEASE
    • VASCULAR CALCIFICATION
    • CARDIOVASCULAR EVENTS
    • DIALYSIS PATIENTS
    • AORTIC STIFFNESS
    • RENAL-DISEASE
    • MORTALITY
    • CALCIUM
    • SUPPLEMENTATION

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