Vitamin K2 supplementation and arterial stiffness among renal transplant recipients: a single-arm, single-center clinical trial (Mansour et al.)
A new study of renal transplant recipients, a group shown to express subclinical vitamin K deficiency and an increased risk of cardiovascular disease, examined whether K2 supplementation would correct this deficiency and thus improve arterial stiffness. The study has published in Journal of the American Society of Hypertension.
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 menaquinone7 (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 dephosphorylateduncarboxylated matrix Gla protein (dpucMGP) >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 previtamin K2 = 9.8 ± 2.2 m/s vs. cfPWV postvitamin K2 = 8.4 ± 1.5 m/s; P < .001). Mean dpucMGP concentrations were also significantly reduced by 55.1% following menaquinone7 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 24hour mean arterial pressure, the improvement in arterial stiffness was independently associated with the reduction in dpucMGP concentration (P = .014).
The researchers concluded that, among renal transplant recipients with stable graft function, vitamin K2 supplementation was associated with improvement in subclinical vitamin K deficiency and arterial stiffness.
Mansour AG et al. Vitamin K2 supplementation and arterial stiffness among renal transplant recipients – a single-arm, single-center clinical trial. J Am Soc Hypertens. 2017 Jul 13. Pii: S1933-1711(17)30255-3.