Division of Nephrology, Ege University School of Medicine, Izmir, Turkey.
Nephrol Dial Transplant. 2012 Feb;27(2):514-21. doi: 10.1093/ndt/gfr321. Epub 2011 Jul 12.
Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs).
BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription-polymerase chain reaction and annexin V staining, respectively.
Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification.
Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations.
血管钙化（VC）主要是由于磷酸盐水平升高引起的，是慢性肾脏病患者的主要问题之一。在临床研究中，已经报道了血清镁与 VC 之间呈负相关。然而，关于镁对细胞水平钙化的影响的信息很少。因此，我们研究了镁对β-甘油磷酸（BGP）诱导的牛血管平滑肌细胞（BVSMCs）钙化的影响。
在 14 天的时间里，将 BVSMCs 用钙化培养基孵育，同时增加镁浓度。通过定量钙、von Kossa 和茜素红染色、实时逆转录聚合酶链反应和 Annexin V 染色，分别测量钙沉积、细胞转分化和细胞凋亡。
随着 BGP 的添加，细胞内钙沉积显著增加，并用镁共孵育可大部分预防。较高的镁水平导致 BGP 诱导的碱性磷酸酶活性抑制以及与 BVSMCs 向成骨样细胞转分化过程相关的基因表达降低。此外，随着培养基中镁浓度的增加，估计进入细胞的钙减少。此外，较高的镁浓度可防止 BGP 诱导的细胞损伤（凋亡）和已建立的钙化进展。
较高的镁水平可预防 BVSMC 钙化，抑制成骨蛋白、凋亡的表达以及已建立的钙化的进一步进展。因此，镁影响与 VC 相关的分子过程，并且在临床情况下也可能具有发挥作用的潜力。
