Clones of interstitial cells from bovine aortic valve exhibit different calcifying potential when exposed to endotoxin and phosphate.
OBJECTIVE
Our purpose was to study in vitro whether phenotypically-distinct interstitial cell clones from bovine aortic valve (BVIC) possess different calcifying potential in response to endotoxin (lipopolysaccharide [LPS]) and phosphate (Pi).


RESULTS
Among various clones of BVIC obtained by limited dilution technique we selected 4 clones displaying different growth patterns and immunophenotypes. Uncloned and cloned cells were treated with combinations of LPS (100 ng/mL) and Pi (2.4 mmol/L). Uncloned BVIC showed increased alkaline phosphatase activity (ALP) after treatment with LPS, which resulted in calcification after addition of Pi. Among BVIC clones, only Clone 1 (fibroblast-like phenotype) showed a relevant increase in ALP after LPS treatment in parallel with prevention of smooth muscle (SM) alpha-actin accumulation. No effect was observed in clonal cells harboring a more stable SM cell-like profile (Clone 4). None of the isolated clones calcified but mineralization was induced in the presence of LPS plus Pi when Clone 1 was cocultured with Clone 4 or after seeding on type I collagen sponges.


CONCLUSIONS
Endotoxin and phosphate can act as valve calcification promoters by targeting specific fibroblast-like interstitial valve cells that possess a unique procalcific potential.
Rattazzi
Marcello
M
Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Padova, Treviso, Italy. marcello.rattazzi@unipd.it
Iop
Laura
L
Faggin
Elisabetta
E
Bertacco
Elisa
E
Zoppellaro
Giacomo
G
Baesso
Ilenia
I
Puato
Massimo
M
Torregrossa
Gianluca
G
Fadini
Gian Paolo
GP
Agostini
Carlo
C
Gerosa
Gino
G
Sartore
Saverio
S
Pauletto
Paolo
P
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001021:Aortic Valve / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D002114:Calcinosis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002999:Clone Cells; D018920:Coculture Techniques; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006349:Heart Valve Diseases / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D010710:Phosphates / Q000633:toxicity*
D008070:Lipopolysaccharides; D010710:Phosphates; D000469:Alkaline Phosphatase; D002118:Calcium