Inactive Matrix Gla Protein, Arterial Stiffness, and Endothelial 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

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

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 β = 0.49) and FMD (standardized β = −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 (US)
Pages (from-to)735-741
Number of pages7
JournalAmerican journal of hypertension
Volume31
Issue number6
DOIs
StatePublished - Jun 1 2018

Keywords

  • African American
  • arterial stiffness
  • blood pressure
  • chronic kidney disease
  • endothelial function
  • hypertension
  • vitamin K

ASJC Scopus subject areas

  • Internal Medicine

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