IS UNDERCARBOXYLATED MATRIX GLA PROTEIN A RELIABLE BIOMARKER OF VITAMIN K2 STATUS IN PATIENTS WITH CHRONIC KIDNEY DISEASE?

Vitamin K2 deficiency is associated with arterial calcification, which is a significant problem in patients with chronic kidney disease. It occurs more rapidly and earlier and appears to be an independent risk factor for higher morbidity and mortality. The ucMGP is considered to be a biomarker for indirect measurement of vitamin K2 status. Purpose: Our study aimed to measure ucMGP levels in patients at different stages of CKD and to evaluate its potential role as a biomarker of vitamin K2 status. Material/Methods: Sixty-seven patients aged between 31 – 87 years took part in the study. They were divided into groups according to glomerular filtration rate: Group I, with GFR ≥90 ml/min, Group II, with GFR 89 – 45 ml/min, Group III, with GFR 44 – 15 ml/min. Venous blood was tested for calcium, phosphate, creatinine and ucMGP. Results: Serum calcium and phosphate levels were within the reference ranges across all groups. Phosphate levels showed a progressive increase, with significantly lower levels in Group III. Mean ucMGP levels decreased from Group I to Group III, although these differences did not reach statistical significance. In Group I, women had significantly lower ucMGP concentrations compared to men. The incidence of CVD increased significantly with the progression of renal failure. Participants with CVD in Group I demonstrated significantly higher ucMGP concentrations compared to Group III. Conclusions: Uncarboxylated MGP can provide information about vitamin K2 and its carboxylation, but it is not a specific or reliable marker of vitamin K2 status.