title: Pro-calcific responses by aortic valve interstitial cells in a novel in vitro model simulating dystrophic calcification.
abstract: Etiopathogenetic mechanisms in calcific aortic valve stenosis are still poorly understood despite this being the third major cause of heart disease in western world. In prior in vitro cultures simulating metastatic calcification, pro-calcific effects on aortic valve interstitial cells (AVICs) resulted by adding bacterial endotoxin lipopolysaccharide (LPS) at high inorganic phosphate (Pi) levels. Here we accomplished improved in vitro models simulating either metastatic (Pi = 2.6 mM) or dystrophic calcification (Pi = 1.3 mM), in which LPS-stimulated bovine AVICs underwent extra-stimulation with macrophage-cytokine-containing media derived from parallel cultures of allogeneic monocyte/macrophages in turn stimulated with LPS. In dystrophic calcification-like cultures, lower calcium amount was spectrometrically assessed with parallel reduced alkaline phosphatase activity with respect to metastatic calcification-like cultures, with an about three-fold slower progression of mineralization. Hydroxyapatite crystal precipitation was ultrastructurally found to correlate with AVIC degeneration processes culminating with the formation of phthalocyanin-positive lipidic layers (PPLs) at the surface of cells and cell-derived matrix-vesicle-like bodies, acting as calcium nucleators according to a pattern mirroring those we had previously found in in vivo conditions. In conclusion, an in vitro model has been developed enabling reliable simulations of the effects exerted on AVICs by putatively pro- or anti-calcific agents.
authors.affiliation: Department of Medical Morphological Research, University of Udine, Italy. fulvia.ortolani@uniud.it
authors.forename: Fulvia
authors.initials: F
authors.lastname: Ortolani
authors.forename: Luca
authors.initials: L
authors.lastname: Rigonat
authors.forename: Antonella
authors.initials: A
authors.lastname: Bonetti
authors.forename: Magali
authors.initials: M
authors.lastname: Contin
authors.forename: Franco
authors.initials: F
authors.lastname: Tubaro
authors.forename: Marcello
authors.initials: M
authors.lastname: Rattazzi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Marchini
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000473:pathology* / Q000503:physiopathology / Q000648:ultrastructure; D001024:Aortic Valve Stenosis / Q000473:pathology* / Q000503:physiopathology; D002114:Calcinosis / Q000473:pathology*; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D042783:Endothelial Cells / Q000473:pathology* / Q000502:physiology / Q000648:ultrastructure; D008070:Lipopolysaccharides / Q000494:pharmacology; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008954:Models, Biological; D009000:Monocytes / Q000378:metabolism / Q000648:ultrastructure; D010710:Phosphates / Q000494:pharmacology
chemical_list: D017077:Culture Media, Conditioned; D008070:Lipopolysaccharides; D010710:Phosphates; D002118:Calcium