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Updated: Apr 20, 2026
Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve In Vitro
Published on: May 10, 2021
Extracellular pyrophosphate is reduced in aortic interstitial valve cells acquiring a calcifying profile:
Marcello Rattazzi1, Elisa Bertacco2, Laura Iop3
1Department of Medicine, University of Padova, Italy; Medicina Interna Iˆ, Ca' Foncello Hospital, Treviso, Italy.
Objectives:
Pyrophosphate (PPi) is a potent inhibitor of ectopic mineralization but its role during aortic valve calcification is not known.
Methods:
Anti-calcific effect of PPi was investigated by using an in vitro model of serum-driven calcification of collagen sponges and decellularized porcine aortic valve leaflets. Bovine interstitial valve cells (VIC), seeded either within the collagen matrices or in transwell chambers, were used to test cellular ability to inhibit serum-induced calcification. PPi metabolism was investigated in clonal VIC harboring different calcifying potential.
Results:
In a cell-free system, high serum levels induced a dose-dependent calcification of type I collagen matrices which was prevented by PPi and ATP supplementation. Blockade of serum-driven calcification by PPi and ATP was also observed when using decellularized porcine aortic valve leaflets. A similar anti-calcific effect was also seen for bovine VIC, either statically seeded into the collagen matrices or co-cultured by using a transwell system. However, when we performed co-culture experiments by using clonal VIC harboring different calcifying potential, we observed that the subset of cells acquiring a pro-calcific profile lost the ability to protect the collagen from serum-driven calcification. Pro-calcific differentiation of the clonal VIC was accompanied by increase in ALP along with significant reduction in NPP activity and ATP/PPi extracellular accumulation. These changes were not observed in the clonal subtype with lower propensity towards calcification.
Conclusions:
We showed that PPi and ATP are potent inhibitors of serum-driven calcification of collagen matrix and that their extracellular accumulation is reduced in calcifying VIC.
