Calcification and extracellular matrix dysregulation in human postmortem and surgical aortic valves

Heart ◽  
2019 ◽  
Vol 105 (21) ◽  
pp. 1616-1621 ◽  
Author(s):  
M Victoria Gomez-Stallons ◽  
Justin T Tretter ◽  
Keira Hassel ◽  
Osniel Gonzalez-Ramos ◽  
Dorothy Amofa ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Aortic Valve ◽  
In Vivo Imaging ◽  
Progressive Disease ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Valve Dysfunction ◽  
Intrinsic Form ◽  
Severe Calcification

ObjectivesCalcific aortic valve disease (CAVD) is a progressive disease ranging from aortic valve (AoV) sclerosis to AoV stenosis (AS), characterised by severe calcification with impaired leaflet function. Due to the lack of early symptoms, the pathological progression towards valve dysfunction is poorly understood. The early patterns of AoV calcification and altered extracellular matrix (ECM) organisation were analysed in individuals postmortem without clinical AS compared with clinical AS.MethodsHistological patterns of calcification and ECM organisation in postmortem AoV leaflets without clinical AS obtained from a tissue repository and surgical specimens obtained from individuals with clinical AS were compared with in vivo imaging prior to transcatheter AoV implantation.ResultsAoV calcification was detected in all samples from individuals >50 years old, with severity increasing with age, independent of known CAVD risk factors. Two distinct types of calcification were identified: ‘Intrinsic’, primarily found at the leaflet hinge of postmortem leaflets, accompanied by abnormal collagen and proteoglycan deposition; and ‘Nodular’, extending from the middle to the tip regions in more severely affected postmortem leaflets and surgical specimens, associated with increased elastin fragmentation and loss of elastin integrity. Even in the absence of increased thickening, abnormalities in ECM composition were observed in postmortem leaflets without clinical AS and worsen in clinical AS.ConclusionsTwo distinct phenotypes of AoV calcification are apparent. While the ‘nodular’ form is recognised on in vivo imaging and is present with CAVD and valve dysfunction, it is unclear if the ‘intrinsic’ form is pathological or detected on in vivo imaging.

scholarly journals Human Aortic Valve Interstitial Cells Display Proangiogenic Properties During Calcific Aortic Valve Disease

2020 ◽  
Author(s):  
Nicolas Gendron ◽  
Mickael Rosa ◽  
Adeline Blandinieres ◽  
Yoann Sottejeau ◽  
Elisa Rossi ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Disease ◽  
Conditioned Media ◽  
Valve Disease ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Valve Interstitial Cells ◽  
Endothelial Colony Forming Cells

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.

scholarly journals Identification of key genes in calcific aortic valve disease via weighted gene co-expression network analysis

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jin-Yu Sun ◽  
Yang Hua ◽  
Hui Shen ◽  
Qiang Qu ◽  
Jun-Yan Kan ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Network Analysis ◽  
Aortic Valve ◽  
Aortic Valve Disease ◽  
Expression Profiles ◽  
Enrichment Analysis ◽  
Valve Disease ◽  
Hub Genes ◽  
Calcific Aortic Valve Disease ◽  
Underlying Mechanisms

Abstract Background Calcific aortic valve disease (CAVD) is the most common subclass of valve heart disease in the elderly population and a primary cause of aortic valve stenosis. However, the underlying mechanisms remain unclear. Methods The gene expression profiles of GSE83453, GSE51472, and GSE12644 were analyzed by ‘limma’ and ‘weighted gene co-expression network analysis (WGCNA)’ package in R to identify differentially expressed genes (DEGs) and key modules associated with CAVD, respectively. Then, enrichment analysis was performed based on Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, DisGeNET, and TRRUST database. Protein–protein interaction network was constructed using the overlapped genes of DEGs and key modules, and we identified the top 5 hub genes by mixed character calculation. Results We identified the blue and yellow modules as the key modules. Enrichment analysis showed that leukocyte migration, extracellular matrix, and extracellular matrix structural constituent were significantly enriched. SPP1, TNC, SCG2, FAM20A, and CD52 were identified as hub genes, and their expression levels in calcified or normal aortic valve samples were illustrated, respectively. Conclusions This study suggested that SPP1, TNC, SCG2, FAM20A, and CD52 might be hub genes associated with CAVD. Further studies are required to elucidate the underlying mechanisms and provide potential therapeutic targets.

scholarly journals Cellular dynamics of EMT: lessons from live in vivo imaging of embryonic development

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jeffrey D. Amack
Keyword(s):  
Extracellular Matrix ◽  
Embryonic Development ◽  
In Vivo Imaging ◽  
Cytoskeletal Proteins ◽  
Cell Junctions ◽  
Model Organisms ◽  
Cellular Dynamics ◽  
Mesenchymal Transition ◽  
Cell Cell

AbstractEpithelial-mesenchymal transition (EMT) refers to a process in which epithelial cells lose apical-basal polarity and loosen cell–cell junctions to take on mesenchymal cell morphologies and invasive properties that facilitate migration through extracellular matrix. EMT—and the reverse mesenchymal-epithelial transition (MET)—are evolutionarily conserved processes that are used throughout embryonic development to drive tissue morphogenesis. During adult life, EMT is activated to close wounds after injury, but also can be used by cancers to promote metastasis. EMT is controlled by several mechanisms that depend on context. In response to cell–cell signaling and/or interactions with the local environment, cells undergoing EMT make rapid changes in kinase and adaptor proteins, adhesion and extracellular matrix molecules, and gene expression. Many of these changes modulate localization, activity, or expression of cytoskeletal proteins that mediate cell shape changes and cell motility. Since cellular changes during EMT are highly dynamic and context-dependent, it is ideal to analyze this process in situ in living organisms. Embryonic development of model organisms is amenable to live time-lapse microscopy, which provides an opportunity to watch EMT as it happens. Here, with a focus on functions of the actin cytoskeleton, I review recent examples of how live in vivo imaging of embryonic development has led to new insights into mechanisms of EMT. At the same time, I highlight specific developmental processes in model embryos—gastrulation in fly and mouse embryos, and neural crest cell development in zebrafish and frog embryos—that provide in vivo platforms for visualizing cellular dynamics during EMT. In addition, I introduce Kupffer’s vesicle in the zebrafish embryo as a new model system to investigate EMT and MET. I discuss how these systems have provided insights into the dynamics of adherens junction remodeling, planar cell polarity signaling, cadherin functions, and cytoskeletal organization during EMT, which are not only important for understanding development, but also cancer progression. These findings shed light on mechanisms of actin cytoskeletal dynamics during EMT, and feature live in vivo imaging strategies that can be exploited in future work to identify new mechanisms of EMT and MET.

scholarly journals Interleukin-37 suppresses the osteogenic responses of human aortic valve interstitial cells in vitro and alleviates valve lesions in mice

2017 ◽  
Vol 114 (7) ◽  
pp. 1631-1636 ◽  
Author(s):  
Qingchun Zeng ◽  
Rui Song ◽  
David A. Fullerton ◽  
Lihua Ao ◽  
Yufeng Zhai ◽  
...  
Keyword(s):  
Aortic Valve ◽  
High Fat Diet ◽  
Aortic Valve Disease ◽  
Valve Disease ◽  
High Fat ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Valve Interstitial Cells ◽  
Valve Lesions ◽  
Osteogenic Factors

Calcific aortic valve disease is a chronic inflammatory process, and aortic valve interstitial cells (AVICs) from diseased aortic valves express greater levels of osteogenic factors in response to proinflammatory stimulation. Here, we report that lower cellular levels of IL-37 in AVICs of diseased human aortic valves likely account for augmented expression of bone morphogenetic protein-2 (BMP-2) and alkaline phosphatase (ALP) following stimulation of Toll-like receptor (TLR) 2 or 4. Treatment of diseased AVICs with recombinant human IL-37 suppresses the levels of BMP-2 and ALP as well as calcium deposit formation. In mice, aortic valve thickening is observed when exposed to a TLR4 agonist or a high fat diet for a prolonged period; however, mice expressing human IL-37 exhibit significantly lower BMP-2 levels and less aortic valve thickening when subjected to the same regimens. A high fat diet in mice results in oxidized low-density lipoprotein (oxLDL) deposition in aortic valve leaflets. Moreover, the osteogenic responses in human AVICs induced by oxLDL are suppressed by recombinant IL-37. Mechanistically, reduced osteogenic responses to oxLDL in human AVICs are associated with the ability of IL-37 to inhibit NF-κB and ERK1/2. These findings suggest that augmented expression of osteogenic factors in AVICs of diseased aortic valves from humans is at least partly due to a relative IL-37 deficiency. Because recombinant IL-37 suppresses the osteogenic responses in human AVICs and alleviates aortic valve lesions in mice exposed to high fat diet or a proinflammatory stimulus, IL-37 has therapeutic potential for progressive calcific aortic valve disease.

scholarly journals COX-2 Is Downregulated in Human Stenotic Aortic Valves and Its Inhibition Promotes Dystrophic Calcification

2020 ◽  
Vol 21 (23) ◽  
pp. 8917
Author(s):  
Francesco Vieceli Dalla Sega ◽  
Francesca Fortini ◽  
Paolo Cimaglia ◽  
Luisa Marracino ◽  
Elisabetta Tonet ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Clinical Analysis ◽  
Dystrophic Calcification ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Inflammatory Drugs ◽  
Cox 2 ◽  
Anti Inflammatory ◽  
Induced Apoptosis ◽  
Human Aortic Valve

Calcific aortic valve disease (CAVD) is the result of maladaptive fibrocalcific processes leading to a progressive thickening and stiffening of aortic valve (AV) leaflets. CAVD is the most common cause of aortic stenosis (AS). At present, there is no effective pharmacotherapy in reducing CAVD progression; when CAVD becomes symptomatic it can only be treated with valve replacement. Inflammation has a key role in AV pathological remodeling; hence, anti-inflammatory therapy has been proposed as a strategy to prevent CAVD. Cyclooxygenase 2 (COX-2) is a key mediator of the inflammation and it is the target of widely used anti-inflammatory drugs. COX-2-inhibitor celecoxib was initially shown to reduce AV calcification in a murine model. However, in contrast to these findings, a recent retrospective clinical analysis found an association between AS and celecoxib use. In the present study, we investigated whether variations in COX-2 expression levels in human AVs may be linked to CAVD. We extracted total RNA from surgically explanted AVs from patients without CAVD or with CAVD. We found that COX-2 mRNA was higher in non-calcific AVs compared to calcific AVs (0.013 ± 0.002 vs. 0.006 ± 0.0004; p < 0.0001). Moreover, we isolated human aortic valve interstitial cells (AVICs) from AVs and found that COX-2 expression is decreased in AVICs from calcific valves compared to AVICs from non-calcific AVs. Furthermore, we observed that COX-2 inhibition with celecoxib induces AVICs trans-differentiation towards a myofibroblast phenotype, and increases the levels of TGF-β-induced apoptosis, both processes able to promote the formation of calcific nodules. We conclude that reduced COX-2 expression is a characteristic of human AVICs prone to calcification and that COX-2 inhibition may promote aortic valve calcification. Our findings support the notion that celecoxib may facilitate CAVD progression.

scholarly journals TLR4 Stimulation Promotes Human AVIC Fibrogenic Activity through Upregulation of Neurotrophin 3 Production

2020 ◽  
Vol 21 (4) ◽  
pp. 1276
Author(s):  
Qingzhou Yao ◽  
Erlinda The ◽  
Lihua Ao ◽  
Yufeng Zhai ◽  
Maren K. Osterholt ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Critical Role ◽  
Chronic Inflammatory Disease ◽  
Collagen Deposition ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Neurotrophin 3 ◽  
Collagen Iii ◽  
Inflammatory Stimuli ◽  
Stimulation Of

Background: Calcific aortic valve disease (CAVD) is a chronic inflammatory disease that manifests as progressive valvular fibrosis and calcification. An inflammatory milieu in valvular tissue promotes fibrosis and calcification. Aortic valve interstitial cell (AVIC) proliferation and the over-production of the extracellular matrix (ECM) proteins contribute to valvular thickening. However, the mechanism underlying elevated AVIC fibrogenic activity remains unclear. Recently, we observed that AVICs from diseased aortic valves express higher levels of neurotrophin 3 (NT3) and that NT3 exerts pro-osteogenic and pro-fibrogenic effects on human AVICs. Hypothesis: Pro-inflammatory stimuli upregulate NT3 production in AVICs to promote fibrogenic activity in human aortic valves. Methods and Results: AVICs were isolated from normal human aortic valves and were treated with lipopolysaccharide (LPS, 0.20 µg/mL). LPS induced TLR4-dependent NT3 production. This effect of LPS was abolished by inhibition of the Akt and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) pathways. The stimulation of TLR4 in human AVICs with LPS resulted in a greater proliferation rate and an upregulated production of matrix metallopeptidases-9 (MMP-9) and collagen III, as well as augmented collagen deposition. Recombinant NT3 promoted AVIC proliferation in a tropomyosin receptor kinase (Trk)-dependent fashion. The neutralization of NT3 or the inhibition of Trk suppressed LPS-induced AVIC fibrogenic activity. Conclusions: The stimulation of TLR4 in human AVICs upregulates NT3 expression and promotes cell proliferation and collagen deposition. The NT3-Trk cascade plays a critical role in the TLR4-mediated elevation of fibrogenic activity in human AVICs. Upregulated NT3 production by endogenous TLR4 activators may contribute to aortic valve fibrosis associated with CAVD progression.

scholarly journals Interstitial cells in calcified aortic valves have reduced differentiation potential and stem cell-like properties

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Bogdanova ◽  
Arsenii Zabirnyk ◽  
Anna Malashicheva ◽  
Katarina Zihlavnikova Enayati ◽  
Tommy Aleksander Karlsen ◽  
...  
Keyword(s):  
Stem Cell ◽  
Aortic Valve ◽  
Collagen Gel ◽  
Interstitial Cells ◽  
Osteogenic Medium ◽  
Calcific Aortic Valve Disease ◽  
Aortic Valves ◽  
Alizarin Red ◽  
Differentiation Potential ◽  
Lower Expression

Abstract Valve interstitial cells (VICs) are crucial in the development of calcific aortic valve disease. The purpose of the present investigation was to compare the phenotype, differentiation potential and stem cell-like properties of cells from calcified and healthy aortic valves. VICs were isolated from human healthy and calcified aortic valves. Calcification was induced with osteogenic medium. Unlike VICs from healthy valves, VICs from calcified valves cultured without osteogenic medium stained positively for calcium deposits with Alizarin Red confirming their calcific phenotype. Stimulation of VICs from calcified valves with osteogenic medium increased calcification (p = 0.02), but not significantly different from healthy VICs. When stimulated with myofibroblastic medium, VICs from calcified valves had lower expression of myofibroblastic markers, measured by flow cytometry and RT-qPCR, compared to healthy VICs. Contraction of collagen gel (a measure of myofibroblastic activity) was attenuated in cells from calcified valves (p = 0.04). Moreover, VICs from calcified valves, unlike cells from healthy valves had lower potential to differentiate into adipogenic pathway and lower expression of stem cell-associated markers CD106 (p = 0.04) and aldehyde dehydrogenase (p = 0.04). In conclusion, VICs from calcified aortic have reduced multipotency compared to cells from healthy valves, which should be considered when investigating possible medical treatments of aortic valve calcification.

Abstract 17341: Novel Lipid Markers of Calcific Aortic Valve Stenosis

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Pascal E Bogaert ◽  
Andrea L Edel ◽  
Arun Surendran ◽  
Michael Raabe ◽  
Shubhkarman Sandhawalia ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Pressure Gradient ◽  
Aortic Valve Stenosis ◽  
Internal Standard ◽  
Aortic Valves ◽  
Genetic Studies ◽  
High Incidence ◽  
Oxidized Phosphatidylcholine ◽  
Human Aortic Valve ◽  
Severe Calcification

Introduction: Calcific aortic valve stenosis (CAVS) is the most prevalent cardiac valvular pathology, leading to a high incidence of morbidity and mortality if left untreated. The exact pathophysiology of CAVS is largely undefined. Genetic studies have shown a strong correlation of the Lp(a) gene to developing CAVS. Lp(a) is known to be the carrier of plasma Oxidized Phosphatidylcholine and results in Lysophosphatidic acid (LPA) accumulation. The focus of the present study was to determine if OxPC and LPA in calcific human aortic valves relate with echocardiographic markers of CAVS. Methods: Aortic valves (n=98) were obtained from patients undergoing AVR. OxPC and LPA were extracted from pulverized aortic valves and analyzed using a targeted mass spectrometry approach. Lipid values are represented relative to an internal standard and normalized by homogenate and leaflet weights. The severity of calcification and aortic stenosis were measured anatomically by Echocardiographic calcification (ECC) score and hemodynamically by mean AV pressure gradient. Results: One-palmitoyl-2-(9-oxo)-nonanoyl- sn- glycero-3-phosphocholine (PONPC) was the most abundant OxPC among 58 OxPC molecules detected (49.3±3.8ng), in AV tissue. When valves were graded by ECC score, scores of 1 (no calcification) had observably attenuated amounts of mean total OxPC’s (135.3±39.3ng) compared to those with a score of 4 (severe calcification) (310.1±34.8 ng). Total valvular OxPC increased linearly with increased ECC score. Total non-fragmented OxPC’s were also significantly lower in valves with ECC scores of 1 and 2 compared to a score of 4 ( P =0.03). Six LPA species were also identified with 16:0 and 18:1 being the most prevalent. Mean AV pressure gradient had a significant, positive correlation with Total LPA amounts (r 2 =0.580, p <0.001), suggesting that elevated LPA concentrations in CAVS tissue is associated with disease severity. Conclusions: Our study is the largest lipidomics study of human aortic valve tissue demonstrating that OxPC and LPA molecules play a significant role in the etiology of CAVS and provides a novel therapeutic target for mitigating disease progression.

Sign in / Sign up

Export Citation Format

Share Document