Metabolic Homeostasis and Vascular Calcification (METABOL)

Figure 1. Representative images of typical vascular calcifications. (A) Computerized tomography (CT) angiography: 3D volume-rendered image shows calcification in the aortic-iliac axis (white) in a haemodialysis patient. (B–D) Curved MIP (maximum intensity projection) views. Cardiac-CT scan shows calcification in the right coronary artery (B) and in the Cx and LAD (C) (arrows). (D) Supra-aortic CT scan shows calcification in the internal and common carotid arteries (arrows). Ao, Aorta; RCA, right coronary artery; LAD, left anterior descending artery; Cx, circumflex artery; LM, left main artery; SA, subclavian artery; CCA, common carotid artery; ICA, internal carotid artery; ECA, external carotid artery. Villa-Bellosta et al. Eur Heart J. 2017.

Figure 2. Schematic representation of a model for vascular calcification. Calcium phosphate crystals deposition depends of equilibrium between concentration of inorganic phosphate (Pi) and synthesis of inhibitors (including pyrophosphate, PPi). Vascular calcification could be induced by (i) lack of synthesis of calcium phosphate crystal inhibitors (e.g. increased PPi degradation via alkaline phosphatase) or (ii) elevated serum Pi concentration (e.g. chronic kidney disease). Villa-Bellosta et al. Eur Heart J. 2017.

Figure 3. Pyrophosphate synthesis increases in VSMCs during phosphate-induced calcification because of compensatory regulation of extracellular pyrophosphate metabolism. Villa-Bellosta. ATVB. 2018.

Figure 4.  Characterization of phosphate-induced calcification and pyrophosphate/ATP hydrolysis in cultured ex vivo aortic rings. A), Representative images of hematosine and eosin (H&E), van Gieson, or trichrome staining performed on aortic rings’ histological section. B), Calcification of normal and devitalized aortic rings (measured as 45-calcium incorporation) incubated ex vivo in minimum essential medium media containing 1 or 2 mmol/L phosphate and 45-calcium as radiotracer for 6 d (top) in the absence or presence of 100 μmol/L levamisole (+Lev) or 100 μmol/L pyrophosphate (+PPi). Representative images (original ×20 magnification) of Alizarin Red or von Kossa staining, performed on aortic rings’ histological section (bottom). C), 45-calcium incorporation in devitalized aortic rings at the indicated concentration of phosphate (top, 1 mmol/L calcium) or calcium (bottom, 2 mmol/L phosphate). D), 32PPi (32-pyrophopshate) hydrolysis at the indicated time in normal and devitalized aortic rings (top), and effects of 100 μmol/L levamisole (+Lev) on pyrophosphate hydrolysis (bottom). E), Kinetic characterization of 32PPi (top) or [γ32P]ATP (bottom) hydrolysis at the indicated inorganic pyrophosphate (PPi) and ATP concentration in normal aortic rings. Villa-Bellosta. ATVB. 2018.

Figure 5. Magnesium improves LmnaG609G/+ vascular smooth muscle cell calcification. A) Scheme showing the principle of the measurement. B) Representative time‐course of 2 mM phosphate on calcification of LmnaG609G/+ VSMCs (up). Calcification was visualized with Alizarin red. Representative microscopic images (10x) showing calcification of treated and untreated LmnaG609G/+ VSMCs (down). C–F) Measures of calcium in treated living LmnaG609G/+ VSMCs (C), treated fixed LmnaG609G/+ VSMCs (D), untreated living LmnaG609G/+ VSMCs (E), and untreated fixed LmnaG609G/+ VSMCs (F). G) The calcification inhibitory capacity was calculated as the difference in calcium deposition between living and fixed cells (ΔCa2+). Villa-Bellosta. EMBO mol med. 2020.