3D-Bioprinting of Valvular Interstitial Cells of Ovine Aortic Valves: Impact of Printing Parameters on Cell Viability

Calcific aortic valve stenosis (CAVS) is a heart disease characterized by the progressive fibro-calcific remodeling of the aortic valves, an actively regulated process with the involvement of the reactive oxygen species-mediated differentiation of valvular interstitial cells (VICs) into osteoblast-like cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of a variety of antioxidant genes, and plays a protective role in valve calcification. Heme oxygenase-1 (HO-1), an Nrf2-target gene, is upregulated in human calcified aortic valves. Therefore, we investigated the effect of Nrf2/HO-1 axis in VIC calcification. We induced osteogenic differentiation of human VICs with elevated phosphate and calcium-containing osteogenic medium (OM) in the presence of heme. Heme inhibited Ca deposition and OM-induced increase in alkaline phosphatase and osteocalcin (OCN) expression. Heme induced Nrf2 and HO-1 expression in VICs. Heme lost its anti-calcification potential when we blocked transcriptional activity Nrf2 or enzyme activity of HO-1. The heme catabolism products bilirubin, carbon monoxide, and iron, and also ferritin inhibited OM-induced Ca deposition and OCN expression in VICs. This study suggests that heme-mediated activation of the Nrf2/HO-1 pathway inhibits the calcification of VICs. The anti-calcification effect of heme is attributed to the end products of HO-1-catalyzed heme degradation and ferritin.

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0312: Characterization of human valvular interstitial cells isolated from normal and fibrocalcified aortic valves

Archives of Cardiovascular Diseases Supplements ◽

10.1016/s1878-6480(14)71463-6 ◽

2014 ◽

Vol 6 ◽

pp. 73

Author(s):

Anais Arbesu Y Miar ◽

Anais Toursel ◽

Alexandre Ung ◽

Rodrigo Lorenzi ◽

Ahmed Elkalioubie ◽

...

Keyword(s):

Interstitial Cells ◽

Valvular Interstitial Cells ◽

Aortic Valves

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Abstract 15192: Leptin Effects on Osteoblast Differentiation of Human Valvular Interstitial Cells: New Insight Into Calcific Aortic Valve Disease

Circulation ◽

10.1161/circ.132.suppl_3.15192 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Mickael Rosa ◽

Rodrigo Lorenzi ◽

Madjid Tagzirt ◽

Francis Juthier ◽

Antoine Rauch ◽

...

Keyword(s):

Aortic Valve ◽

Aortic Valve Disease ◽

Osteoblast Differentiation ◽

Interstitial Cells ◽

Valve Disease ◽

Calcium Deposition ◽

Valvular Interstitial Cells ◽

Calcific Aortic Valve Disease ◽

Aortic Valves ◽

Alp Activity

Introduction: Calcific aortic valve disease (CAVD) affects 2% to 6% of the population over 65 years and results from dysregulated processes such as calcification, supported in part by the osteoblast differentiation of valvular interstitial cells (VIC), the most prevalent cell type in the human aortic valves. Leptin has recently been linked to aortic valve calcification in ApoE-/- mice. Hypothesis: Our hypothesis is that leptin could play a role in the calcifying processes implicated in CAVD via direct effects on human VIC. Methods: Patients who underwent aortic valve replacement for severe CAVD (n=43) or with coronary artery disease (CAD) but without CAVD (n=129) were included in this study. Presence of leptin was analyzed in human explanted calcified aortic valves and blood samples. Leptin receptors expression was analyzed in aortic valves and VIC isolated from aortic valves. Leptin effects on osteoblast differentiation of VIC in presence or not of Akt and ERK inhibitors were investigated by alizarin red staining, alkaline phosphatase (ALP) activity, and RT-qPCR analysis for osteopontin, ALP, bone morphogenetic protein BMP-2, and RUNX2. Results: Patients with CAVD have significant higher serum leptin concentration than CAD patients (p=0.002). The presence of leptin was observed by immunochemistry in human calcified aortic valves, with higher concentrations in calcified vs non-calcified zones (p=0.01). Both short and long leptin receptor isoforms were expressed in VIC. Chronic leptin stimulation of VIC enhanced ALP, BMP-2 and RUNX2 expression and decreased osteopontin expression. This treatment led to a higher, dose dependent, ALP activity and calcium deposition in VIC. Inhibiting Akt or ERK during leptin stimulation led to a reduced calcification by bringing the expression of calcification genes to the control levels. Conclusions: Together, these novel findings depict the potential role of leptin in the process of CAVD by triggering calcification processes in human VIC.

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