ABSTRACT
Comparative in vitro study examined the osteogenic potential of interstitial cells of aortic valve obtained from the patients with aortic stenosis and from control recipients of orthotopic heart transplantation with intact aortic valve. The osteogenic inductors augmented mineralization of aortic valve interstitial cells (AVIC) in patients with aortic stenosis in comparison with the control level. Native AVIC culture of aortic stenosis patients demonstrated overexpression of osteopontin gene (OPN) and underexpression of osteoprotegerin gene (OPG) in comparison with control levels. In both groups, AVIC differentiation was associated with overexpression of RUNX2 and SPRY1 genes. In AVIC of aortic stenosis patients, expression of BMP2 gene was significantly greater than the control level. The study revealed an enhanced sensitivity of AVIC to osteogenic inductors in aortic stenosis patients, which indicates probable implication of OPN, OPG, and BMP2 genes in pathogenesis of aortic valve calcification.
Subject(s)
Aortic Valve Stenosis/genetics , Aortic Valve/pathology , Calcinosis/genetics , Osteoblasts/metabolism , Osteogenesis/genetics , Stromal Cells/metabolism , Tricuspid Valve/metabolism , Aged , Aortic Valve/metabolism , Aortic Valve/surgery , Aortic Valve Stenosis/metabolism , Aortic Valve Stenosis/pathology , Aortic Valve Stenosis/surgery , Ascorbic Acid/pharmacology , Bone Morphogenetic Protein 2/genetics , Bone Morphogenetic Protein 2/metabolism , Calcinosis/metabolism , Calcinosis/pathology , Calcinosis/surgery , Cell Differentiation , Core Binding Factor Alpha 1 Subunit/genetics , Core Binding Factor Alpha 1 Subunit/metabolism , Dexamethasone/pharmacology , Female , Gene Expression Regulation , Glycerophosphates/pharmacology , Heart Transplantation , Humans , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Middle Aged , Osteoblasts/drug effects , Osteoblasts/pathology , Osteogenesis/drug effects , Osteopontin/genetics , Osteopontin/metabolism , Osteoprotegerin/genetics , Osteoprotegerin/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Primary Cell Culture , Stromal Cells/drug effects , Stromal Cells/pathology , Tricuspid Valve/pathology , Tricuspid Valve/surgeryABSTRACT
AIMS: Calcific aortic valve disease is the most common heart valve disease in the Western world. Bicuspid and tricuspid aortic valve calcifications are traditionally considered together although the dynamics of the disease progression is different between the two groups of patients. Notch signaling is critical for bicuspid valve development and NOTCH1 mutations are associated with bicuspid valve and calcification. We hypothesized that Notch-dependent mechanisms of valve mineralization might be different in the two groups. METHODS AND RESULTS: We used aortic valve interstitial cells and valve endothelial cells from patients with calcific aortic stenosis with bicuspid or tricuspid aortic valve. Expression of Notch-related genes in valve interstitial cells by qPCR was different between bicuspid and tricuspid groups. Discriminant analysis of gene expression pattern in the interstitial cells revealed that the cells from calcified bicuspid valves formed a separate group from calcified tricuspid and control cells. Interstitial cells from bicuspid calcified valves demonstrated significantly higher sensitivity to stimuli at early stages of induced proosteogenic differentiation and were significantly more sensitive to the activation of proosteogenic OPN, ALP and POSTIN expression by Notch activation. Notch-activated endothelial-to-mesenchymal transition and the corresponding expression of HEY1 and SLUG were also more prominent in bicuspid valve derived endothelial cells compared to the cells from calcified tricuspid and healthy valves. CONCLUSION: Early signaling events including Notch-dependent mechanisms that are responsible for the initiation of aortic valve calcification are different between the patients with bicuspid and tricuspid aortic valves.
