Two Photon Excited Fluorescence Microscopy Metrics are Sensitive to Early Phenotypic Changes in Calcific Aortic Valve Disease In Vitro and Ex Vivo

2020 ◽  
Vol 4 (sup1) ◽  
pp. 94-95
Author(s):  
Ishita Tandon ◽  
Kartik Balachandran
2017 ◽  
Vol 115 (3) ◽  
pp. E363-E371 ◽  
Author(s):  
Ana M. Porras ◽  
Jennifer A. Westlund ◽  
Austin D. Evans ◽  
Kristyn S. Masters

An insufficient understanding of calcific aortic valve disease (CAVD) pathogenesis remains a major obstacle in developing treatment strategies for this disease. The aim of the present study was to create engineered environments that mimic the earliest known features of CAVD and apply this in vitro platform to decipher relationships relevant to early valve lesion pathobiology. Glycosaminoglycan (GAG) enrichment is a dominant hallmark of early CAVD, but culture of valvular interstitial cells (VICs) in biomaterial environments containing pathological amounts of hyaluronic acid (HA) or chondroitin sulfate (CS) did not directly increase indicators of disease progression such as VIC activation or inflammatory cytokine production. However, HA-enriched matrices increased production of vascular endothelial growth factor (VEGF), while matrices displaying pathological levels of CS were effective at retaining lipoproteins, whose deposition is also found in early CAVD. Retained oxidized low-density lipoprotein (oxLDL), in turn, stimulated myofibroblastic VIC differentiation and secretion of numerous inflammatory cytokines. OxLDL also increased VIC deposition of GAGs, thereby creating a positive feedback loop to further enrich GAG content and promote disease progression. Using this disease-inspired in vitro platform, we were able to model a complex, multistep pathological sequence, with our findings suggesting distinct roles for individual GAGs in outcomes related to valve lesion progression, as well as key differences in cell–lipoprotein interactions compared with atherosclerosis. We propose a pathogenesis cascade that may be relevant to understanding early CAVD and envision the extension of such models to investigate other tissue pathologies or test pharmacological treatments.


2013 ◽  
Vol 34 (suppl 1) ◽  
pp. P3908-P3908 ◽  
Author(s):  
J. Hjortnaes ◽  
G. Gamci-Unal ◽  
C. Goettsch ◽  
K. Scherer ◽  
L. Lax ◽  
...  

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Ling Sun ◽  
John LeCluyse ◽  
Brian Robillard ◽  
Philippe Sucosky

INTRODUCTION: Calcific aortic valve disease (CAVD) is an active process presumably triggered by interplays between atherogenic risk factors, molecular signaling networks and hemodynamic cues. While our earlier work demonstrated that progressive alterations in fluid wall-shear stress (WSS) on the fibrosa could trigger leaflet inflammation, the mechanisms of CAVD pathogenesis secondary to side-specific WSS abnormalities are poorly understood. HYPOTHESIS: Supported by our previous studies, we hypothesize that valve leaflets are sensitive to both WSS magnitude and pulsatility and that abnormalities in either promote CAVD development. OBJECTIVE: This study aims at elucidating ex vivo the contribution of isolated and combined alterations in WSS magnitude and pulsatility to valvular calcification. METHODS: The fibrosa and ventricularis of porcine leaflets were subjected simultaneously to different combinations of WSS magnitude and pulsatility (i.e., physiologic, sub- and supra-physiologic levels) for 48 hours in a double-sided shear stress bioreactor. Endothelial activation (ICAM-1, VCAM-1), paracrine expression (TGF-β and BMP-4), and proteinase/collagenase expression (MMP-2, cathepsin L) were detected by immunohistochemistry, while osteogenic differentiation (α-SMA) was assessed via western blot. RESULTS: Regardless of the magnitude or frequency, non-physiologic WSS conditions did not result in endothelial activation. Tissue exposure to either supra-physiologic WSS magnitude or pulsatility significantly upregulated paracrine (74-fold increase), proteinase (4-fold increase), collagenase (5-fold increase) and α-SMA (23-fold increase) expressions relative to the levels measured under physiologic WSS. In contrast, combined alterations in WSS magnitude and pulsatility downregulated those responses. CONCLUSION: This study demonstrates the sensitivity of aortic valve leaflets to both WSS magnitude and pulsatility and the ability of supra-physiologic WSS magnitude or pulsatility to trigger events involved in early CAVD pathogenesis. The results provide new potential insights into the mechanisms of CAVD secondary to hypertension and Paget’s disease, which are associated with abnormal blood flow and leaflet WSS.


Author(s):  
Ling Sun ◽  
Philippe Sucosky

Calcific aortic valve disease (CAVD) is an active process presumably triggered by interplays between atherogenic risk factors, molecular signaling networks and hemodynamic cues. While our earlier work demonstrated that progressive alterations in fluid shear stress (FSS) on the fibrosa could trigger valvular inflammation [1], the mechanisms of CAVD pathogenesis secondary to side-specific FSS abnormalities are poorly understood. Supported by our previous studies, we hypothesize that valve leaflets are sensitive to both WSS magnitude and pulsatility and that abnormalities in either promote CAVD development. This study aims at elucidating ex vivo the contribution of isolated and combined alterations in FSS magnitude and pulsatility to valvular calcification.


2017 ◽  
Vol 1 (11) ◽  
pp. 914-924 ◽  
Author(s):  
Lauren M. Baugh ◽  
Zhiyi Liu ◽  
Kyle P. Quinn ◽  
Sam Osseiran ◽  
Conor L. Evans ◽  
...  

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 474
Author(s):  
Andreas Weber ◽  
Melissa Pfaff ◽  
Friederike Schöttler ◽  
Vera Schmidt ◽  
Artur Lichtenberg ◽  
...  

The hallmarks of calcific aortic valve disease (CAVD), an active and regulated process involving the creation of calcium nodules, lipoprotein accumulation, and chronic inflammation, are the significant changes that occur in the composition, organization, and mechanical properties of the extracellular matrix (ECM) of the aortic valve (AV). Most research regarding CAVD is based on experiments using two-dimensional (2D) cell culture or artificially created three-dimensional (3D) environments of valvular interstitial cells (VICs). Because the valvular ECM has a powerful influence in regulating pathological events, we developed an in vitro AV tissue culture model, which is more closely able to mimic natural conditions to study cellular responses underlying CAVD. AV leaflets, isolated from the hearts of 6–8-month-old sheep, were fixed with needles on silicon rubber rings to achieve passive tension and treated in vitro under pro-degenerative and pro-calcifying conditions. The degeneration of AV leaflets progressed over time, commencing with the first visible calcified domains after 14 d and winding up with the distinct formation of calcium nodules, heightened stiffness, and clear disruption of the ECM after 56 d. Both the expression of pro-degenerative genes and the myofibroblastic differentiation of VICs were altered in AV leaflets compared to that in VIC cultures. In this study, we have established an easily applicable, reproducible, and cost-effective in vitro AV tissue culture model to study pathological mechanisms underlying CAVD. The valvular ECM and realistic VIC–VEC interactions mimic natural conditions more closely than VIC cultures or 3D environments. The application of various culture conditions enables the examination of different pathological mechanisms underlying CAVD and could lead to a better understanding of the molecular mechanisms that lead to VIC degeneration and AS. Our model provides a valuable tool to study the complex pathobiology of CAVD and can be used to identify potential therapeutic targets for slowing disease progression.


2015 ◽  
Vol 10 (2) ◽  
pp. 108 ◽  
Author(s):  
Daniel Alejandro Lerman ◽  
Sai Prasad ◽  
Nasri Alotti ◽  
◽  
◽  
...  

Calcification occurs in atherosclerotic vascular lesions and in the aortic valve. Calcific aortic valve disease (CAVD) is a slow, progressive disorder that ranges from mild valve thickening without obstruction of blood flow, termed aortic sclerosis, to severe calcification with impaired leaflet motion, termed aortic stenosis. In the past, this process was thought to be ‘degenerative’ because of time-dependent wear and tear of the leaflets, with passive calcium deposition. The presence of osteoblasts in atherosclerotic vascular lesions and in CAVD implies that calcification is an active, regulated process akin to atherosclerosis, with lipoprotein deposition and chronic inflammation. If calcification is active, via pro-osteogenic pathways, one might expect that development and progression of calcification could be inhibited. The overlap in the clinical factors associated with calcific valve disease and atherosclerosis provides further support for a shared disease mechanism. In our recent research we used an in vitro porcine valve interstitial cell model to study spontaneous calcification and potential promoters and inhibitors. Using this model, we found that denosumab, a human monoclonal antibody targeting the receptor activator of nuclear factor-κB ligand may, at a working concentration of 50 μg/mL, inhibit induced calcium deposition to basal levels.


Author(s):  
Shinji Goto ◽  
Maximillian A. Rogers ◽  
Mark C. Blaser ◽  
Hideyuki Higashi ◽  
Lang H. Lee ◽  
...  

Author(s):  
Nicolas Gendron ◽  
Mickael Rosa ◽  
Adeline Blandinieres ◽  
Yoann Sottejeau ◽  
Elisa Rossi ◽  
...  

Objective: The study’s aim was to analyze the capacity of human valve interstitial cells (VICs) to participate in aortic valve angiogenesis. Approach and Results: VICs were isolated from human aortic valves obtained after surgery for calcific aortic valve disease and from normal aortic valves unsuitable for grafting (control VICs). We examined VIC in vitro and in vivo potential to differentiate in endothelial and perivascular lineages. VIC paracrine effect was also examined on human endothelial colony-forming cells. A pathological VIC (VIC p ) mesenchymal-like phenotype was confirmed by CD90 + /CD73 + /CD44 + expression and multipotent-like differentiation ability. When VIC p were cocultured with endothelial colony-forming cells, they formed microvessels by differentiating into perivascular cells both in vivo and in vitro. VIC p and control VIC conditioned media were compared using serial ELISA regarding quantification of endothelial and angiogenic factors. Higher expression of VEGF (vascular endothelial growth factor)-A was observed at the protein level in VIC p -conditioned media and confirmed at the mRNA level in VIC p compared with control VIC. Conditioned media from VIC p induced in vitro a significant increase in endothelial colony-forming cell proliferation, migration, and sprouting compared with conditioned media from control VIC. These effects were inhibited by blocking VEGF-A with blocking antibody or siRNA approach, confirming VIC p involvement in angiogenesis by a VEGF-A dependent mechanism. Conclusions: We provide here the first proof of an angiogenic potential of human VICs isolated from patients with calcific aortic valve disease. These results point to a novel function of VIC p in valve vascularization during calcific aortic valve disease, with a perivascular differentiation ability and a VEGF-A paracrine effect. Targeting perivascular differentiation and VEGF-A to slow calcific aortic valve disease progression warrants further investigation.


2017 ◽  
Vol 131 (3) ◽  
pp. 181-195 ◽  
Author(s):  
Casper F.T. van der Ven ◽  
Pin-Jou Wu ◽  
Mark W. Tibbitt ◽  
Alain van Mil ◽  
Joost P.G. Sluijter ◽  
...  

Calcific aortic valve disease (CAVD) is the most prevalent valvular heart disease. Valve interstitial cells (VICs) mediate calcification in the aortic valve (AV) leaflets, leading to aortic stenosis (AS) and eventually heart failure. Aortic valve replacement (AVR) surgery is the only available treatment. Drug-based therapies and the in vitro models to study CAVD are inadequate or lacking. Here, we present a forward-looking review of 3D CAVD models, miRNA-based therapeutics and controlled drug-delivery strategies.


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