Plasma Desphospho-Uncarboxylated Matrix Gla Protein as a Marker of Kidney Damage and Cardiovascular Risk in Advanced Stage of Chronic Kidney Disease
Previous studies showed that lower vitamin K intake in patients with chronic kidney disease (CKD) is associated with increased desphospho-uncarboxylated matrix Gla protein level (dp-ucMGP). The plasma desphospho-ucMGP fraction is considered as a marker of vascular vitamin K status and a risk marker for CV morbidity and mortality.
The vitamin K insufficiency established in the majority of hemodialysis (HD) and advanced CKD patients may contribute to their strongly increased cardiovascular risk. Randomized placebo-controlled trials showed a significant reduction of plasma dp-ucMGP levels after supplementation with vitamin K2 (menaquinone; MK-7) in healthy postmenopausal women and in HD patients.
With that in mind, the aim of this study was to investigate the association of plasma dp-ucMGP concentrations with kidney function and traditional and non-traditional risk factors of CVD before and after 270 days substitution of 90 mcg of menaquinone-7 (as MenaQ7) in addition to 10 mcg of cholecalciferol in non-dialysis patients with CKD stage 4 and 5.
The level of plasma dp-ucMGP corresponded to the stage of CKD. Patients with stage 5 had significantly higher level of dpucMGP than patients on stage 4. Vitamin K2 supplementation resulted in a significant decrease of dp-ucMGP level by 10.7%.
Additionally, the authors showed a strong inverse association between kidney function assessed by eGFR and plasma dp-ucMGP concentrations in non-dialysis patients with CKD stage 4-5. “A positive association was found between serum creatinine and plasma dp-ucMGP,” says Dr. Katarzyna Maresz, president of the International Science and Health Foundation, and one of the study researchers.
“These data are consistent with a recent observation that CKD patients are at risk of vitamin K deficiency and show impaired MGP carboxylation status,” she adds. “The study confirmed that blood hemoglobin was also associated with plasma dp-ucMGP, which may be explained by assuming that anemia develops together with loss of kidney function.”
The authors concluded that high dp-ucMGP levels, reflecting a poor vitamin K status, seems to be associated with kidney damage and may be also a marker of cardiovascular risk in CKD patients. Oral supplementation of vitamin K2 may improve the carboxylation status of vitamin K-dependent proteins in non-dialyzed CKD patients.
Kurnatowska I, Grzelak P, Masajtis-Zagajewska A, Kaczmarska M, Stefanczyk L, Vermeer C, Maresz K, Nowicki M. Plasma Desphospho-Uncarboxylated Matrix Gla Protein as a Marker of Kidney Damage and Cardiovascular Risk in Advanced Stage of Chronic Kidney Disease. Kidney Blood Press Res 2016;41:231-239.