Individuals who are on hemodialysis have an impaired function of matrix GLA protein (MGP), which, when activated by vitamin K, has an inhibitory effect on vascular calcification. As a result, a team of researchers supported by vitamin K2 manufacturer Gnosis by Lesaffre investigated whether administration of vitamin K2 as MK-7 would have an inhibitory effect on the progression of vascular calcification in patients receiving dialysis.
 
According to the findings, which were published in Kidney International Reports, a thrice-weekly dose of 360 mcg of MK-7 for 18 months was not enough to make a significant difference in measures of coronary artery calcification (CAC) in 138 patients, despite the fact that a vitamin K-dependent increase in activated MGP has reduced CAC in healthy populations in other research.
 
The single-center, prospective, open-label interventional trial was consistent with three smaller studies evaluating the role of vitamin K2 on vascular calcification in dialysis patients.
 
It may be possible that a higher dose of vitamin K2 could provide significant differences, however, many other factors might contribute to the initiation and progression of vascular calcification via mechanisms that vitamin K doesn’t influence.
 
“This study found that vitamin K2 supplementation did not attenuate vascular calcification or arterial stiffness at a dose of 360 mcg three times per week, which strongly suggests that kidney patients on dialysis would need higher doses to achieve protection benefit against arterial calcification,” said Sophie Legrain-Raspaud, research and application director at Gnosis by Lesaffre.
 
Despite the negative findings, there were some promising results in prior studies which investigated Gnosis by Lesaffre’s branded MK-7, MenaQ7. A positive result was found in a 2015 clinical trial on kidney patients, in which the treatment group saw improvements in subclinical vitamin K deficiencies and arterial stiffness.  Another trial, published in 2017, found an improvement in arterial elasticity in dialysis patients following vitamin K2 treatment. Similar outcomes were also found in 2022.
 
“There is a clear need for the optimization of vitamin K status in kidney patients, and this study is critically important in helping to understand what doses will ultimately work to provide protective cardiovascular benefits to individuals on hemodialysis,” said Legrain-Raspaud. “In the progress of researching an ingredient, some studies will not find a conclusive benefit due to any number of reasons. This knowledge gained helps guide future trials that could yield the hypothesized results, particularly once a beneficial dose range is pinpointed.”
 
“While the present study findings might be characterized as ‘unsuccessful,’ it should not hinder enthusiasm to proceed forward as this is integral to a sound exploratory scientific method,” said Marc Philouze, general manager at Gnosis by Lesaffre. “Rather, the insights gained help design future trials to answer clinically highly relevant questions. The pursuit of scientific knowledge and discovery is not always so straightforward.”