Abstract: 【Abstract】Objective To investigate the correlation between the levels of serum dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP) and vitamin K2 and the vascular calcification (VC) in patients with chronic kidney disease (CKD). Methods A total of 98 CKD patients and 70 healthy people were recruited as the research subjects. Serum dp-ucMGP and vitamin K2 were measured by ELISA, and VC was detected by color Doppler ultrasound and lateral abdominal X-ray examinations. The correlation between dp-uc- MGP and vitamin K2 levels and the VC was then analyzed. Results Serum dp-ucMGP increased (Z=-7.767, P＜0.001) and vitamin K2 decreased (t=16.006, P＜0.001) in CKD group as compared with those in control group. In CKD patients with VC, parathyroid hormone (PTH), alkaline phosphatase (ALP), dp-ucMGP and patients’age were higher (VC in carotid artery: Z=- 2.231, - 2.831, - 5.739 and - 4.130 respectively; P=0.026, 0.005,＜0.001 and ＜0.001 respectively. VC in abdominal aorta: Z=-2.299, -3.415, -4.637 and -3.317 respectively; P=0.022, 0.001, <0.001 and 0.001 respectively), while serum vitamin K2 was lower, as compared with those in CKD patients without VC (VC in carotid artery: Z=- 3.936, P＜0.001; VC in abdominal aorta: t= 5.423, P＜0.001). Logistic regression analysis showed that age, dp-ucMGP and vitamin K2 were the independent risk factors for VC in CKD patients (VC in carotid artery: OR=1.080, 4.777 and 0.160 respectively;95% CI=1.022～1.142, 2.125～10.740 and 0.035～0.733 respectively; P=0.006, <0.001 and 0.018 respectively. VC in abdominal aorta: OR=1.066, 2.259 and 0.104 respectively; 95% CI=1.012～1.123, 1.182～4.317 and 0.023～0.466 respectively; P=0.016, 0.014 and 0.003 respectively). Correlation analysis showed that serum dp-ucMGP was positively correlated with PTH, ALP and age (rs=0.684, 0.620 and 0.278 respectively, P＜0.001, ＜0.001 and =0.006 respectively), and negatively correlated with serum vitamin K2 (rs=- 0.271, P=0.007). Serum dp-ucMGP was higher in the CKD patients with severe VC than in those with moderate and mild VC, while serum vitamin K2 was lower in the CKD patients with severe VC than in those with mild VC (F=12.378 and 4.478, P<0.001 and =0.017). Conclusion Older age, higher dp-ucMGP and lower vitamin K2 were the independent risk factors for VC in CKD patients.

Key words: Dephosphorylated uncarboxylated matrix Gla protein, Vitamin K2, Chronic kidney disease, Vascular calcification