Vitamin K2 supplementation and arterial stiffness among renal transplant recipients—a single-arm, single-center clinical trial

• Published in: Journal of the American Society of Hypertension Vol. 11; no. 9; pp. 589 - 597
• Main Authors: Mansour, Anthony G., Hariri, Essa, Daaboul, Yazan, Korjian, Serge, El Alam, Andrew, Protogerou, Athanase D., Kilany, Hala, Karam, Albert, Stephan, Antoine, Bahous, Sola Aoun
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2017
• Subjects: Adult; Biomarkers - blood; Calcium-Binding Proteins - blood; Dietary Supplements; Extracellular Matrix Proteins - blood; Female; Humans; Kidney Failure, Chronic - blood; Kidney Failure, Chronic - therapy; Kidney Transplantation; Male; Matrix Gla Protein; Menaquinone; Middle Aged; Pilot Projects; Prevalence; Prospective Studies; Pulse Wave Analysis; pulse wave velocity; Renal Dialysis; Treatment Outcome; Vascular Calcification - blood; Vascular Calcification - drug therapy; Vascular Calcification - epidemiology; Vascular Stiffness - drug effects; Vitamin K - blood; Vitamin K 2 - therapeutic use; Vitamin K Deficiency - blood; Vitamin K Deficiency - drug therapy; Vitamin K Deficiency - epidemiology; Vitamins - therapeutic use; pulse wave velocity; Menaquinone
• ISSN: 1933-1711; 1878-7436; 1878-7436
• DOI: 10.1016/j.jash.2017.07.001

Subclinical vitamin K deficiency is prevalent among renal transplant recipients and is associated with an increased risk of cardiovascular disease. However, the association between vitamin K supplementation and improvement of arterial stiffness has not been explored in the renal transplant population. The KING trial (vitamin K2 In reNal Graft) is a single-arm study that evaluated the association between the change in vitamin K status and indices of arterial stiffness following 8 weeks of menaquinone-7 (vitamin K2) supplementation (360 μg once daily) among renal transplant recipients (n = 60). Arterial stiffness was measured using carotid-femoral pulse wave velocity (cfPWV). Subclinical vitamin K deficiency was defined as plasma concentration of dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP) >500 pmol/L.At baseline, 53.3% of the study subjects had subclinical vitamin K deficiency. Supplementation was associated with a 14.2% reduction in mean cfPWV at 8 weeks (cfPWV pre-vitamin K2 = 9.8 ± 2.2 m/s vs. cfPWV post-vitamin K2 = 8.4 ± 1.5 m/s; P < .001). Mean dp-ucMGP concentrations were also significantly reduced by 55.1% following menaquinone-7 supplementation with a reduction in the prevalence of subclinical deficiency by 40% (P = .001). When controlled for age, durations of hemodialysis and transplantation, and the change in 24-hour mean arterial pressure, the improvement in arterial stiffness was independently associated with the reduction in dp-ucMGP concentration (P = .014).Among renal transplant recipients with stable graft function, vitamin K2 supplementation was associated with improvement in subclinical vitamin K deficiency and arterial stiffness. (Clinicaltrials.gov: NCT02517580). •Vitamin K2 deficiency is prevalent among renal transplant recipients.•Vitamin K2 supplementation is associated with reduction in dephosphorylated-uncarboxylated matrix Gla protein.•Oral vitamin K2 for 8 weeks is associated with improved arterial stiffness.•The most improvement was observed in patients with baseline vitamin K deficiency.