Plasma Desphospho-Uncarboxylated Matrix Gla Protein as a Marker of Kidney Damage and Cardiovascular Risk in Advanced Stage of Chronic Kidney Disease

Background/Aims: Desphospho-uncarboxylated matrix Gla protein (dp-ucMGP) is formed as a result of vitamin K insufficiency. The aim of this study was to investigate the association between plasma dp-ucMGP, kidney function and cardiovascular risk factors before and after 9-months substitution of vitamin K2 in non-dialysis patients with chronic kidney disease (CKD) stage 4 and 5. Methods: 38 CKD patients were supplemented for 270 +/- 12 days with 90 mu g vitamin K2 and 10 mu g cholecalciferol or 10 mu g cholecalciferol alone. At baseline and at follow-up circulating calcium, phosphate, lipids, hemoglobin, albumin and total protein, dp-ucMGP, osteoprotegerin, fetuin A, osteocalcin and fibroblast grown factor 23 (FGF-23) were assessed. Proteinuria was assessed in the first morning void. Results: Baseline plasma dp-ucMGP was 1018.6 +/- 498.3 pmol/l and was significantly higher in patients at stage 5 CKD (1388.3 +/- 505.4 pmol/l) than at stage 4 (885.1 +/- 419.7 pmol/l), p=0.04. Vitamin K2 supplementation resulted in a decrease of dp-ucMGP level by 10.7%. Plasma dp-ucMGP was positively associated with proteinuria, serum creatinine, PTH and FGF-23; and inversely associated with glomerular filtration rate, serum hemoglobin and albumin. Conclusions: High dp-ucMGP level, 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. Supplementation with vitamin K2 may improve the carboxylation status of MGP. (C) 2016 The Author(s) Published by S. Karger AG, Basel