Interstitial cells from left-sided heart valves display more calcification potential than from right-sided valves: an in-vitro study of porcine valves.
OBJECTIVE
The calcification of cardiac valves is more frequently observed on left-sided (aortic or mitral) than right-sided (pulmonic or tricuspid) valves. The cause of this preferential left-sided calcification remains relatively unknown. The study aim was to evaluate the capacity of interstitial cells isolated from the four cardiac valves of healthy adult pigs to calcify in culture.


METHODS
Interstitial cells were isolated from the valve leaflets of three healthy young pigs and cultured in DMEM/fetal bovine serum (10%) in the presence or absence of osteogenic additives (ascorbic acid, dexamethasone, beta-glycerophosphate).


RESULTS
The proliferation rate was similar for cells from each of the four valves. After longer periods of culture (> 10 days), cells from each valve spontaneously formed several calcification nodules, the process being accelerated in the presence of osteogenic additives (to 4-7 days). Alkaline phosphatase (AP) activity was highest in cells originating from the aortic and mitral valves, respectively, and least in those from the pulmonic and tricuspid valves. Culture with the osteogenic additives increased the AP activity by at least 50% for each valve, but the relative AP activity between cells from each valve origin tended to remain similar (aortic > mitral > pulmonic > tricuspid). Interestingly, the levels of matrix Gla-protein mRNA (an endogenous calcification inhibitor) followed an opposite trend of expression for each valve.


CONCLUSIONS
Interstitial cells from porcine cardiac valves share similarities, although the capacity to calcify is more evident in cells from valves of the left side of the heart. Interstitial cells from the aortic valve displayed the greatest potential for calcification.
Institut de cardiologie de Québec, Centre de recherche Hôpital Laval, Université Laval, 2725 Chemin Sainte-Foy, Québec, (Québec) G1V 4G5, Canada.
Joanie
J
Bouchard-Martel
Elise
E
Roussel
Marie-Claude
MC
Drolet
Marie
M
Arsenault
Jacques
J
Couet
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002114:Calcinosis / Q000473:pathology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D003239:Connective Tissue Cells / Q000378:metabolism / Q000473:pathology*; D006351:Heart Valves / Q000378:metabolism / Q000473:pathology*; D013552:Swine
D000469:Alkaline Phosphatase