Department of Integrated Medicine and Informatics, Ehime University Graduate School of Medicine, Toon City, Japan.
Kidney Blood Press Res. 2010;33(1):66-71. doi: 10.1159/000289575. Epub 2010 Mar 2.
The development of vascular calcification is an active, highly regulated process with similarities to bone formation. Osteocalcin (OC), a vitamin K-dependent protein expressed by osteoblasts, contains 3 gamma-carboxyglutamic acid residues derived from the vitamin K-dependent posttranslational modification of glutamic acid residues. Circulating undercarboxylated OC (ucOC) is increased in vitamin K deficiency and serum ucOC is reported to be a clinical marker of vitamin K status. Vitamin K deficiency is associated with vascular calcification as well as osteoporosis. We evaluated the relationship between ucOC and carotid artery calcification in 92 patients with essential hypertension. Ultrasound of the common carotid artery was performed to identify vascular calcification and subjects were divided into 2 groups: a calcification (+) group and a calcification (-) group. Serum creatinine and ucOC levels were higher in the calcification (+) group than in the calcification (-) group and serum ucOC correlated with serum creatinine. To identify the independent determinant factor for carotid artery calcification, we applied both ucOC and estimated glomerular filtration rate as independent factors in logistic regression analysis. Serum ucOC was an independent determinant of carotid calcification, suggesting that circulating ucOC may be an important biomarker of carotid artery calcification.
血管钙化的发展是一个活跃的、高度调节的过程，与骨形成有相似之处。骨钙素（OC）是成骨细胞表达的一种维生素 K 依赖性蛋白，含有 3 个来自谷氨酸残基的维生素 K 依赖性翻译后羧化的γ-羧基谷氨酸残基。循环中未羧化的 OC（ucOC）在维生素 K 缺乏时增加，据报道血清 ucOC 是维生素 K 状态的临床标志物。维生素 K 缺乏与血管钙化以及骨质疏松症有关。我们评估了 92 例原发性高血压患者的 ucOC 与颈动脉钙化之间的关系。对颈总动脉进行超声检查以识别血管钙化，并将受试者分为钙化（+）组和钙化（-）组。钙化（+）组的血清肌酐和 ucOC 水平高于钙化（-）组，且血清 ucOC 与血清肌酐相关。为了确定颈动脉钙化的独立决定因素，我们将 ucOC 和估计肾小球滤过率作为独立因素应用于逻辑回归分析。血清 ucOC 是颈动脉钙化的独立决定因素，表明循环中的 ucOC 可能是颈动脉钙化的一个重要生物标志物。
