Vitamin K2 Improves Arterial Stiffness in Renal Transplant Patients
A new study of renal transplant recipients, a group shown to express subclinical vitamin K deficiency, 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.
This Lebanese study evaluated in the KING trial (a single-arm pilot study) to see if there is an association between vitamin K2 supplementation and the change in both subclinical vitamin K status and indices of arterial stiffness among 60 renal transplant recipients with stable graft function. The results showed that 8 weeks of MK-7 supplementation (360 mcg/day as MenaQ7®) was associated with significant improvement in arterial stiffness and 24-hour peripheral and central pressures. The mean reduction in cfPWV was 1.4 m/s, which was well beyond the reduction of 1 m/s recommended for a clinically relevant vascular effect.
According to the researchers, prior observational studies have shown the prevalence of subclinical vitamin K deficiency has been reported to be as high as 80% in the renal transplant population. Moreover, in kidney transplant recipients, Vitamin K insufficiency, expressed as a high circulating level of dp-ucMGP (dephosphorylated-uncarboxylated matrix Gla protein, or “inactive” MGP, a K-dependent protein), is associated independently with increased risk of mortality. However, any studies to date have not addressed whether vitamin K supplementation may lead to improved outcomes after kidney transplantation.
In addition, MK-7 supplementation improved vitamin K status, which was represented by the reduction in dp-ucMGP concentrations. A positive correlation was present between the reduction in arterial stiffness, a surrogate of early cardiovascular disease, and the circulating concentration of dp-ucMGP, a marker of subclinical vascular vitamin K deficiency and calcification.
The main conclusion was that, among renal transplant recipients with stable graft function, vitamin K2 supplementation was associated with improvement in subclinical K deficiency and arterial stiffness. According to the researchers, the findings from this trial support the hypothesis that subclinical vitamin K deficiency may be a modifiable cardiovascular risk factor and may improve with MK-7 supplementation.
“While previous cardiovascular study in healthy postmenopausal women showed an improvement in arterial elasticity after 3 years of supplementation, the results collected in this trial were especially impressive as the statistically significant effect was seen very quickly,” says Dr. Katarzyna Maresz, president of the International Science and Health Foundation. “After just 8 weeks of MK-7 supplementation, low vitamin K status represented by dpucMGP level was significantly reduced by 55.1%. Moreover, supplementation was associated with a 14.2% reduction in mean cfPWV.
“One can assume that longer MK-7 supplementation may lead to even better results, and secure improvement in cardiovascular outcomes in renal transplant patients,” adds Maresz.