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 language | English |
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Pages (from-to) | 735-741 |
Number of pages | 7 |
Journal | American Journal of Hypertension |
Volume | 31 |
Issue number | 6 |
DOIs | |
Publication status | Published - 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