Vessel calcification is a recognised cardiovascular morbidity risk factor in patients with
chronic kidney disease (CKD). Recent reports indicate a significant role of Matrix
Gla-protein (MGP) in decreasing calcification processes. MGP is excretion protein whose
mechanism of action is not yet fully explained and which to be activated requires
phosphorylation and carboxylation where cofactor is vitamin K. Immunohistochemical tests
showed a high level of un-carboxylated MGP in calcified vessels. These observations indicate
that shortage of vitamin K is a significant risk factor for the development of vessel
calcification. On the other hand CKD patients often display shortages of this vitamin.
Another calcification risk factor in CKD patients are calcium-phosphate disturbances and
insufficiency of vitamin D3 which in physiological concentration stimulates MGP
transcription. Cranenburg et al. showed a decrease vessel calcification in dialysis patients
treated with vitamin K2. Vitamin K2 exists in two forms K1 and K2, however only the K2 form
displays calcification decreasing properties. There are currently no similar studies in
patients with chronic kidney disease who do not require renal replacement therapy.
The aim of study. The aim of this study is estimation of influence of vitamin K2
administration over the period of 9 months on vessel calcification in 3.- 5. stage CKD
patients.
Materials and methods. It is a prospective, randomised double-blind study carried out in
parallel groups. 60 patients with CKD (GFR 15-60 ml/min) whose renal replacement therapy is
to commence not earlier than in 9 months are planned to be qualified for the study. After
familiarizing the patients with the aims of the study and obtaining their written consent,
non-invasive tests will be carried out in order to estimate the presence and degree of vessel
calcification: common carotid artery intima media thickness (CCA-IMT) by ultrasound
examination, coronary artery calcium score (CACS) by multiscan CT as well as the presence of
calcified heart valves by ultrasound examination. Patients with calcium score >10 (Agatston
scoring system) will be qualified for the study. On the basis of randomised selection,
patients will be divided into two groups: 30 patients will be given 90 μg vitamin K2+10 μg
cholecalciferol (Vitamin D)and 30 patients will be given only 10 μg cholecalciferol. After a
9-month treatment the image diagnostic will be carried out in order to estimate the degree of
vessel calcification. Patients and their basic laboratory test will be evaluated during the
study period by a nephrologists on a monthly basis. First, at the commencement of the study,
then after 3, 6 and finally after 9 months during the last visit, 10 ml of serum and plasma
will be taken and frozen in order to conduct special marking tests: phosphorylated MGP
(pMGP), uncarboxylated MGP (ucMGP), 25-OH cholecalciferol, hsCRP.
Scheduling Study Visits:
Visit 0 Screening Period
Review of inclusion and exclusion criteria
Obtain informed consent
Obtain weight and height
Obtain CACS, CCA-IMT
Obtain heart ultrasonography
Review concomitant therapy
Visit 1 - Randomization
Review of inclusion and exclusion criteria
Medical history for concomitant disorders (hypertension, heart ischemic diseases,
diabetes mellitus)
Collect blood for serum chemistry (creatinine, albumin, intact PTH, calcium, phosphor,
uric acid, lipids, glucose, kaolin-kephalin time, prothrombin index and blood
morphology.
Collect blood for pMGP, ucMGP, 25-OH cholecalciferol, hsCRP
Review concomitant therapy
Randomization to: 90 μg vitamin K2+10μg cholecalciferol or 10μg cholecalciferol (Vitamin
D) during 9 months
Visit 2,4,5,7,8 Visits every month
Complete physical examination
GFR obtain
Drug dispension
Visit 3,6 and after 9 months:
Complete physical examination
GFR obtain
Collect blood for serum chemistry (creatinine, albumin, intact PTH, calcium, phosphor,
uric acid, lipids, glucose, kaolin-kephalin time, prothrombin index and blood
morphology.
Collect blood for pMGP, ucMGP, 25-OH cholecalciferol, hsCRP
Obtain CACS, CCA-IMT
Obtain heart ultrasonography
Review concomitant therapy