Magnesium modulates the expression levels of calcification-associated factors to inhibit calcification in a time-dependent manner

Abstract

Vascular calcification, a common complication in patients with chronic kidney disease, involves a variety of mechanisms associated with the regulation of calcification-associated factors. Previous clinical studies have indicated that magnesium is involved in the reduction of vascular calcification; however, the mechanism underlying this process remains unknown. The aim of the present study was to investigate the effects of magnesium on β-glycerophosphate (β-GP)-induced calcification and the underlying mechanisms. Primary rat vascular smooth muscle cells (VSMCs) were exposed to 10 mM β-GP in medium with or without the addition of 3 mM magnesium or 2-aminoethoxy-diphenylborate (2-APB; an inhibitor of magnesium transport), for a 14-day period. Calcium deposition and alkaline phosphatase (ALP) activity were measured by Alizarin red staining, quantification of calcium and enzyme-linked immunosorbent assay. The expression levels of core-binding factor α-1 (Cbfα1), matrix Gla protein (MGP) and osteopontin (OPN) were determined by reverse transcription-polymerase chain reaction or western blot analysis, following incubation for 0, 3, 6, 10 and 14 days with the different media. VSMC calcification and ALP activity was reduced significantly in the high-magnesium medium compared with the calcification medium, during the 14-day incubation. The magnesium-induced changes in the VSMCs included a β-GP-induced downregulation of Cbfα1 by day 3 of incubation, an effect that was gradually enhanced over the 14-day period. By contrast, magnesium produced notable increases in MGP and OPN expression levels, with an opposite pattern to that observed in the Cbfα1 expression levels. However, the addition of 2-APB appeared to inhibit the protective effect of magnesium on the VSMCs. Therefore, magnesium was able to effectively reduce β-GP-induced calcification in rat VSMCs by regulating the expression levels of calcification-associated factors in a time-dependent manner.

Lower serum magnesium is associated with vascular calcification in peritoneal dialysis patients: a cross sectional study

“…Several other studies have demonstrated an association between lower serum Mg and mortality among dialysis patients [21, 22, 24–27] This association could potentially be attributable to low serum Mg causing accelerated vascular calcification. Increasing data from in-vitro and animal studies support the assertion that Mg acts as an inhibitor of vascular calcification [6–12]. The addition of Mg to vascular smooth muscle cells increases the expression of anti-calcification proteins, such as matrix G1a, bone morphogenetic protein-7 and osteopontin, and inhibits an osteoblastic transformation [7, 11].…”

“…However, there has been comparatively little exploration of the association of serum magnesium (Mg) with vascular calcification. Both in-vitro and animal studies have found that the addition of Mg to vascular smooth muscle cells inhibits the increase in mineralization associated with an osteoblastic phenotype, increases the expression of anti-calcification proteins, and down regulates pathways necessary for the development of vascular calcification [6–12]. The transient receptor potential melastin (TRPM)7 cation channel as well as the Wnt/β-catenin pathway are proposed as being essential to Mg regulating vascular calcification [7, 11].…”

Current and potential therapeutic strategies for the management of vascular calcification in patients with chronic kidney disease including those on dialysis

“…Magnesium plays an important role in vascular health, with normal magnesium homeostasis in VSMC maintained via TRPM7 cation channels. Magnesium prevents posttranscriptional changes in VSMC differentiation and apoptosis and up‐regulates VC inhibitors (MGP and osteopontin), whilst counteracting expression of osteogenic transcription factors (BMP‐2, RUNX2, Msh homeobox 2, and SRY‐ box 9), bone proteins and genes associated with matrix mineralization (osteocalcin and TNAP) . In animal models of VC, dietary supplementation with magnesium results in marked reduction in VC and mortality, improved mineral metabolism, including lowering of PTH, as well as improvement in renal function …”

Serum magnesium and its association with vascular calcification in chronic kidney disease patients on haemodialysis

“…12 Both in-vitro and animal studies have found that the Mg addition to vascular smooth muscle cells inhibits the increase in mineralization associated with increase in expression of anticalcification proteins, and down regulates pathways necessary for the development of vascular calcification. [13][14][15][16][17][18][19] A study has demonstrated that a higher serum Mg significantly decreased the mortality risk in haemodialysis patients and lower serum Mg level has been found to be associated with increased mortality in them. [20][21][22][23] In the present study, a cross sectional study has been conducted to characterize the relationship between Mg level and vascular calcification.…”