Development of calcific aortic valve disease: Do we know enough for new clinical trials?

Causal association between triglycerides and cholesterol-lowering medication with non-rheumatic valve disease: A 2-sample Mendelian randomization study

Previous studies have found a possible causal relationship between triglycerides and lipid-lowering drugs and valvular disease. The aim of this study was to explore the potential causal relationship between triglycerides and lipid-lowering drugs and valvular disease using Mendelian randomization (MR) analysis. Data sets associated with triglycerides (441,016 participants and 12,321,875 single nucleotide polymorphisms [SNPs]) and cholesterol-lowering drugs (209,638 participants and 9851,867 SNPs) were retrieved from the Genome-Wide Association Study (GWAS) database. A total of 297 and 49 SNPs significantly associated with triglycerides and cholesterol-lowering drugs, respectively (P < 5 × 10-8), were identified. Similarly, data sets for non-rheumatic valve diseases (NVDs) (361,194 participants and 10,080,950 SNPs) were obtained from the GWAS database. Inverse variance weighting was used as the primary method for calculating the odds ratio (OR) and 95% confidence intervals (CI). The MR-Egger, weighted median, and weighted mode analyses were also used to test the robustness of the main results. The MR-Egger intercept test and the MR-PRESSO test were used to evaluate horizontal pleiotropy. Inverse variance weighted (IVW) results showed that both triglyceride and cholesterol-lowering medication were positively associated with NVDs (OR = 1.001, 95% CI 1.000-1.0012, P = 0.006; OR = 1.007, 95% CI 1.003-1.010; P = 0.002). This study suggests that both triglyceride and cholesterol-lowering medications are positively associated with NVDs, suggesting that lowering triglyceride levels or the use of cholesterol-lowering medications may reduce the incidence of NVDs. However, larger samples are required for further validation.

Comparison study of surface-initiated hydrogel coatings with distinct side-chains for improving biocompatibility of polymeric heart valves

Polymeric heart valves (PHVs) present a promising alternative for treating valvular heart diseases with satisfactory hydrodynamics and durability against structural degeneration. However, the cascaded coagulation, inflammatory responses, and calcification in the dynamic blood environment pose significant challenges to the surface design of current PHVs. In this study, we employed a surface-initiated polymerization method to modify polystyrene-block-isobutylene-block-styrene (SIBS) by creating three hydrogel coatings: poly(2-methacryloyloxy ethyl phosphorylcholine) (pMPC), poly(2-acrylamido-2-methylpropanesulfonic acid) (pAMPS), and poly(2-hydroxyethyl methacrylate) (pHEMA). These hydrogel coatings dramatically promoted SIBS's hydrophilicity and blood compatibility at the initial state. Notably, the pMPC and pAMPS coatings maintained a considerable platelet resistance performance after 12 h of sonication and 10 000 cycles of stretching and bending. However, the sonication process induced visible damage to the pHEMA coating and attenuated the anti-coagulation property. Furthermore, the in vivo subcutaneous implantation studies demonstrated that the amphiphilic pMPC coating showed superior anti-inflammatory and anti-calcification properties. Considering the remarkable stability and optimal biocompatibility, the amphiphilic pMPC coating constructed by surface-initiated polymerization holds promising potential for modifying PHVs.

Investigation of autophagy‑related genes and immune infiltration in calcific aortic valve disease: A bioinformatics analysis and experimental validation

The present study aimed to elucidate the role of autophagy-related genes (ARGs) in calcific aortic valve disease (CAVD) and their potential interactions with immune infiltration via experimental verification and bioinformatics analysis. A total of three microarray datasets (GSE12644, GSE51472 and GSE77287) were obtained from the Gene Expression Omnibus database, and gene set enrichment analysis was performed to identify the relationship between autophagy and CAVD. After differentially expressed genes and differentially expressed ARGs (DEARGs) were identified using CAVD samples and normal aortic valve samples, a functional analysis was performed, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, protein-protein interaction network construction, hub gene identification and validation, immune infiltration and drug prediction. The results of the present study indicated a significant relationship between autophagy and CAVD. A total of 46 DEARGs were identified. GO and pathway enrichment analyses revealed the complex roles of DEARGs in regulating CAVD, including multiple gene functions and pathways. A total of 10 hub genes were identified, with three (SPP1, CXCL12 and CXCR4) consistently upregulated in CAVD samples compared with normal aortic valve samples in multiple datasets and experimental validation. Immune infiltration analyses demonstrated significant differences in immune cell proportions between CAVD samples and normal aortic valve samples, thus showing the crucial role of immune infiltration in CAVD development. Furthermore, therapeutic drugs were predicted that could target the identified hub genes, including bisphenol A, resveratrol, progesterone and estradiol. In summary, the present study illuminated the crucial role of autophagy in CAVD development and identified key ARGs as potential therapeutic targets. In addition, the observed immune cell infiltration and predicted autophagy-related drugs suggest promising avenues for future research and novel CAVD treatments.

Remnant cholesterol and the risk of aortic valve calcium progression: insights from the MESA study

BACKGROUND

Remnant cholesterol (RC) is implicated in the risk of cardiovascular disease. However, comprehensive population-based studies elucidating its association with aortic valve calcium (AVC) progression are limited, rendering its precise role in AVC ambiguous.

METHODS

From the Multi-Ethnic Study of Atherosclerosis database, we included 5597 individuals (61.8 ± 10.1 years and 47.5% men) without atherosclerotic cardiovascular disease at baseline for analysis. RC was calculated as total cholesterol minus high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), as estimated by the Martin/Hopkins equation. Using the adjusted Cox regression analyses, we examined the relationships between RC levels and AVC progression. Furthermore, we conducted discordance analyses to evaluate the relative AVC risk in RC versus LDL-C discordant/concordant groups.

RESULTS

During a median follow-up of 2.4 ± 0.9 years, 568 (10.1%) participants exhibited AVC progression. After adjusting for traditional cardiovascular risk factors, the HRs (95% CIs) for AVC progression comparing the second, third, and fourth quartiles of RC levels with the first quartile were 1.195 (0.925-1.545), 1.322 (1.028-1.701) and 1.546 (1.188-2.012), respectively. Notably, the discordant high RC/low LDL-C group demonstrated a significantly elevated risk of AVC progression compared to the concordant low RC/LDL-C group based on their medians (HR, 1.528 [95% CI 1.201-1.943]). This pattern persisted when clinical LDL-C threshold was set at 100 and 130 mg/dL. The association was consistently observed across various sensitivity analyses.

CONCLUSIONS

In atherosclerotic cardiovascular disease-free individuals, elevated RC is identified as a residual risk for AVC progression, independent of traditional cardiovascular risk factors. The causal relationship of RC to AVC and the potential for targeted RC reduction in primary prevention require deeper exploration.

Multiscale multimodal characterization and simulation of structural alterations in failed bioprosthetic heart valves

Calcific degeneration is the most frequent type of heart valve failure, with rising incidence due to the ageing population. The gold standard treatment to date is valve replacement. Unfortunately, calcification oftentimes re-occurs in bioprosthetic substitutes, with the governing processes remaining poorly understood. Here, we present a multiscale, multimodal analysis of disturbances and extensive mineralisation of the collagen network in failed bioprosthetic bovine pericardium valve explants with full histoanatomical context. In addition to highly abundant mineralized collagen fibres and fibrils, calcified micron-sized particles previously discovered in native valves were also prevalent on the aortic as well as the ventricular surface of bioprosthetic valves. The two mineral types (fibres and particles) were detectable even in early-stage mineralisation, prior to any macroscopic calcification. Based on multiscale multimodal characterisation and high-fidelity simulations, we demonstrate that mineral occurrence coincides with regions exposed to high haemodynamic and biomechanical indicators. These insights obtained by multiscale analysis of failed bioprosthetic valves serve as groundwork for the evidence-based development of more durable alternatives. STATEMENT OF SIGNIFICANCE: Bioprosthetic valve calcification is a well-known clinically significant phenomenon, leading to valve failure. The nanoanalytical characterisation of bioprosthetic valves gives insights into the highly abundant, extensive calcification and disorganization of the collagen network and the presence of calcium phosphate particles previously reported in native cardiovascular tissues. While the collagen matrix mineralisation can be primarily attributed to a combination of chemical and mechanical alterations, the calcified particles are likely of host cellular origin. This work presents a straightforward route to mineral identification and characterization at high resolution and sensitivity, and with full histoanatomical context and correlation to hemodynamic and biomechanical indicators, hence providing design cues for improved bioprosthetic valve alternatives.

Challenges of aortic valve tissue culture - maintenance of viability and extracellular matrix in the pulsatile dynamic microphysiological system

BACKGROUND

Calcific aortic valve disease (CAVD) causes an increasing health burden in the 21st century due to aging population. The complex pathophysiology remains to be understood to develop novel prevention and treatment strategies. Microphysiological systems (MPSs), also known as organ-on-chip or lab-on-a-chip systems, proved promising in bridging in vitro and in vivo approaches by applying integer AV tissue and modelling biomechanical microenvironment. This study introduces a novel MPS comprising different micropumps in conjunction with a tissue-incubation-chamber (TIC) for long-term porcine and human AV incubation (pAV, hAV).

RESULTS

Tissue cultures in two different MPS setups were compared and validated by a bimodal viability analysis and extracellular matrix transformation assessment. The MPS-TIC conjunction proved applicable for incubation periods of 14-26 days. An increased metabolic rate was detected for pulsatile dynamic MPS culture compared to static condition indicated by increased LDH intensity. ECM changes such as an increase of collagen fibre content in line with tissue contraction and mass reduction, also observed in early CAVD, were detected in MPS-TIC culture, as well as an increase of collagen fibre content. Glycosaminoglycans remained stable, no significant alterations of α-SMA or CD31 epitopes and no accumulation of calciumhydroxyapatite were observed after 14 days of incubation.

CONCLUSIONS

The presented ex vivo MPS allows long-term AV tissue incubation and will be adopted for future investigation of CAVD pathophysiology, also implementing human tissues. The bimodal viability assessment and ECM analyses approve reliability of ex vivo CAVD investigation and comparability of parallel tissue segments with different treatment strategies regarding the AV (patho)physiology.

Embedding and Backscattered Scanning Electron Microscopy (EM-BSEM) Is Preferential over Immunophenotyping in Relation to Bioprosthetic Heart Valves

Hitherto, calcified aortic valves (AVs) and failing bioprosthetic heart valves (BHVs) have been investigated by similar approaches, mostly limited to various immunostaining techniques. Having employed multiple immunostaining combinations, we demonstrated that AVs retain a well-defined cellular hierarchy even at severe stenosis, whilst BHVs were notable for the stochastic degradation of the extracellular matrix (ECM) and aggressive infiltration by ECM-digesting macrophages. Leukocytes (CD45+) comprised ≤10% cells in the AVs but were the predominant cell lineage in BHVs (≥80% cells). Albeit cells with uncertain immunophenotype were rarely encountered in the AVs (≤5% cells), they were commonly found in BHVs (≥80% cells). Whilst cell conversions in the AVs were limited to the endothelial-to-mesenchymal transition (represented by CD31+α-SMA+ cells) and the formation of endothelial-like (CD31+CD68+) cells at the AV surface, BHVs harboured numerous macrophages with a transitional phenotype, mostly CD45+CD31+, CD45+α-SMA+, and CD68+α-SMA+. In contrast to immunostaining, which was unable to predict cell function in the BHVs, our whole-specimen, nondestructive electron microscopy approach (EM-BSEM) was able to distinguish between quiescent and matrix-degrading macrophages, foam cells, and multinucleated giant cells to conduct the ultrastructural analysis of organelles and the ECM, and to preserve tissue integrity. Hence, we suggest EM-BSEM as a technique of choice for studying the cellular landscape of BHVs.

Sam68 promotes osteogenic differentiation of aortic valvular interstitial cells by TNF-α/STAT3/autophagy axis

Calcified aortic valve disease (CAVD) is a major non-rheumatic heart valve disease in the world, with a high mortality rate and without suitable pharmaceutical therapy due to its complex mechanisms. Src-associated in mitosis 68-KD (Sam68), an RNA binding protein, has been reported as a signaling adaptor in numerous signaling pathways (Huot in Mol Cell Biol, 29(7), 1933-1943, 2009), particularly in inflammatory signaling pathways. The effects of Sam68 on the osteogenic differentiation process of hVICs and its regulation on signal transducer and activator of transcription 3 (STAT3) signaling pathway have been investigated in this study. Human aortic valve samples detection found that Sam68 expression was up-regulated in human calcific aortic valves. We used tumor necrosis factor α (TNF-α) as an activator for osteogenic differentiation in vitro and the result indicated that Sam68 was highly expressed after TNF-α stimulation. Overexpression of Sam68 promoted osteogenic differentiation of hVICs while Sam68 knockdown reversed this effect. Sam68 interaction with STAT3 was predicted by using String database and was verified in this study. Sam68 knockdown reduced phosphorylation of STAT3 activated by TNF-α and the downstream gene expression, which further influenced autophagy flux in hVICs. STAT3 knockdown alleviated the osteogenic differentiation and calcium deposition promoted by Sam68 overexpression. In conclusion, Sam68 interacts with STAT3 and participates in its phosphorylation to promote osteogenic differentiation of hVICs to induce valve calcification. Thus, Sam68 may be a new therapeutic target for CAVD. Regulatory of Sam68 in TNF-α/STAT3/Autophagy Axis in promoting osteogenesis of hVICs.

Oxidized phospholipids facilitate calcific aortic valve disease by elevating ATF4 through the PERK/eIF2α axis

In this study we sought to analyze the critical role of oxidized phospholipid (OxPL) in the progression of calcific aortic valve disease (CAVD) with the involvement of activating transcription factor 4 (ATF4). Differentially expressed genes related to CAVD were identified using bioinformatics analysis. Expression of ATF4 was examined in mouse models of aortic valve calcification (AVC) induced by the high cholesterol (HC) diet. Valvular interstitial cells (VICs) were then isolated from mouse non-calcified valve tissues, induced by osteogenic induction medium (OIM) and co-cultured with OxPAPC-stimulated macrophages. The effect of OxPLs regulating ATF4 on the macrophage polarization and osteogenic differentiation of VICs was examined with gain- and loss-of-function experiments in VICs and in vivo. In aortic valve tissues and OIM-induced VICs, ATF4 was highly expressed. ATF4 knockdown alleviated the osteogenic differentiation of VICs, as evidenced by reduced expression of bone morphogenetic protein-2 (BMP2), osteopontin (OPN), and osteocalcin. In addition, knockdown of ATF4 arrested the AVC in vivo. Meanwhile, OxPL promoted M1 polarization of macrophages and mediated osteogenic differentiation of VICs. Furthermore, OxPL up-regulated ATF4 expression through protein kinase R-like endoplasmic reticulum kinase (PERK)/eukaryotic translation initiation factor 2 subunit alpha (eIF2α) pathway. In conclusion, OxPL can potentially up-regulate the expression of ATF4, inducing macrophages polarized to M1 phenotype, osteogenic differentiation of VICs and AVC, thus accelerating the progression of CAVD.

Genetics of aortic valve disease

PURPOSE OF REVIEW

Aortic valve disease is a leading global cause of morbidity and mortality, posing an increasing burden on society. Advances in next-generation technologies and disease models over the last decade have further delineated the genetic and molecular factors that might be exploited in development of therapeutics for affected patients. This review describes several advances in the molecular and genetic understanding of AVD, focusing on bicuspid aortic valve (BAV) and calcific aortic valve disease (CAVD).

RECENT FINDINGS

Genomic studies have identified a myriad of genes implicated in the development of BAV, including NOTCH1 , SMAD6 and ADAMTS19 , along with members of the GATA and ROBO gene families. Similarly, several genes associated with the initiation and progression of CAVD, including NOTCH1 , LPA , PALMD , IL6 and FADS1/2 , serve as the launching point for emerging clinical trials.

SUMMARY

These new insights into the genetic contributors of AVD have offered new avenues for translational disease investigation, bridging molecular discoveries to emergent pharmacotherapeutic options. Future studies aimed at uncovering new genetic associations and further defining implicated molecular pathways are fuelling the new wave of drug discovery.

Circulating Progenitor Cells Are Associated With Bioprosthetic Aortic Valve Deterioration: A Preliminary Study

Background Mechanisms underlying bioprosthetic valve deterioration are multifactorial and incompletely elucidated. Reparative circulating progenitor cells, and conversely calcification-associated osteocalcin expressing circulating progenitor cells, have been linked to native aortic valve deterioration. However, their role in bioprosthetic valve deterioration remains elusive. This study sought to evaluate the contribution of different subpopulations of circulating progenitor cells in bioprosthetic valve deterioration. Methods and Results This single-center prospective study enrolled 121 patients who had peripheral blood mononuclear cells isolated before bioprosthetic aortic valve replacement and had an echocardiographic follow-up ≥2 years after the procedure. Using flow cytometry, fresh peripheral blood mononuclear cells were analyzed for the surface markers CD34, CD133, and osteocalcin. Bioprosthetic valve deterioration was evaluated by hemodynamic valve deterioration (HVD) using echocardiography, which was defined as an elevated mean transprosthetic gradient ≥30 mm Hg or at least moderate intraprosthetic regurgitation. Sixteen patients (13.2%) developed HVD during follow-up for a median of 5.9 years. Patients with HVD showed significantly lower levels of reparative CD34⁺CD133⁺ cells and higher levels of osteocalcin-positive cells than those without HVD (CD34⁺CD133⁺ cells: 125 [80, 210] versus 270 [130, 420], P=0.002; osteocalcin-positive cells: 3060 [523, 5528] versus 670 [180, 1930], P=0.005 respectively). Decreased level of CD34⁺CD133⁺ cells was a significant predictor of HVD (hazard ratio, 0.995 [95% CI, 0.990%-0.999%]). Conclusions Circulating levels of CD34⁺CD133⁺ cells and osteocalcin-positive cells were significantly associated with the subsequent occurrence of HVD in patients undergoing bioprosthetic aortic valve replacement. Circulating progenitor cells might play a vital role in the mechanism, risk stratification, and a potential therapeutic target for patients with bioprosthetic valve deterioration.

Proteolytic Degradation Is a Major Contributor to Bioprosthetic Heart Valve Failure

Background Whereas the risk factors for structural valve degeneration (SVD) of glutaraldehyde-treated bioprosthetic heart valves (BHVs) are well studied, those responsible for the failure of BHVs fixed with alternative next-generation chemicals remain largely unknown. This study aimed to investigate the reasons behind the development of SVD in ethylene glycol diglycidyl ether-treated BHVs. Methods and Results Ten ethylene glycol diglycidyl ether-treated BHVs excised because of SVD, and 5 calcified aortic valves (AVs) replaced with BHVs because of calcific AV disease were collected and their proteomic profile was deciphered. Then, BHVs and AVs were interrogated for immune cell infiltration, microbial contamination, distribution of matrix-degrading enzymes and their tissue inhibitors, lipid deposition, and calcification. In contrast with dysfunctional AVs, failing BHVs suffered from complement-driven neutrophil invasion, excessive proteolysis, unwanted coagulation, and lipid deposition. Neutrophil infiltration was triggered by an asymptomatic bacterial colonization of the prosthetic tissue. Neutrophil elastase, myeloblastin/proteinase 3, cathepsin G, and matrix metalloproteinases (MMPs; neutrophil-derived MMP-8 and plasma-derived MMP-9), were significantly overexpressed, while tissue inhibitors of metalloproteinases 1/2 were downregulated in the BHVs as compared with AVs, together indicative of unbalanced proteolysis in the failing BHVs. As opposed to other proteases, MMP-9 was mostly expressed in the disorganized prosthetic extracellular matrix, suggesting plasma-derived proteases as the primary culprit of SVD in ethylene glycol diglycidyl ether-treated BHVs. Hence, hemodynamic stress and progressive accumulation of proteases led to the extracellular matrix degeneration and dystrophic calcification, ultimately resulting in SVD. Conclusions Neutrophil- and plasma-derived proteases are responsible for the loss of BHV mechanical competence and need to be thwarted to prevent SVD.

Poly(2-methoxyethyl acrylate) coated bioprosthetic heart valves by copolymerization with enhanced anticoagulant, anti-inflammatory, and anti-calcification properties

Commercial glutaraldehyde (Glut) cross-linked bioprosthetic heart valves (BHVs) fabricated from the pericardium have become the most popular choice for treating heart valve diseases. Nevertheless, thrombosis, inflammation and calcification might lead to structural valve degeneration (SVD), which limited the durability of BHVs. Herein, to improve the biocompatibility of BHVs, we fabricated a poly-(2-methoxyethyl acrylate) (PMEA) coated porcine pericardium (PMEA-PP) through grafting PMEA to the porcine pericardium (PP) that was pre-treated with Glut and methacrylated polylysine. PMEA coating mitigated the side effects caused by aldehyde residues. It was shown that the PMEA coating reduced cytotoxicity and inflammation reactions and improved endothelialization potential, and its hydrophilic surface improved the anti-thrombotic properties of PPs. And the PMEA coating significantly reduced the calcification of PPs. This strategy promoted the endothelialization potential and improve the anti-thrombosis and anti-calcification properties of BHVs, and is expected to overcome the defects of commercial BHVs.

Global burden of calcific aortic valve disease and attributable risk factors from 1990 to 2019

Background

Calcific aortic valve disease (CAVD) was highly prevalent among developed countries and caused numerous deaths. Based on the Global Burden of Disease 2019, this study was designed to present comprehensive epidemiological information, attributable risks, and relevant factors.

Methods

All data were available online via the Global Health Data Exchange (GHDx). In this study, we analyzed the global incidence, prevalence, deaths, and disability-adjusted life years (DALYs) of CAVD across different regions from 1990 to 2019. We applied the estimated annual percentage changes (EAPCs) to evaluate the change trends and their attributable risks. In addition, we explored several relevant factors.

Results

From 1990 to 2019, the incidence cases, prevalence cases, CAVD-related deaths, and DALYs of CAVD gradually increased globally. However, the age-standardized death rate (ASDR) was relatively stable, and the age-standardized DALYs rate gradually declined during the past 30 years. Males and elderly individuals were more likely to suffer from CAVD. High systolic blood pressure (SBP) was the predominant attributable risk of disease burden that presented a global downward trend (death: EAPC = -0.68, 95% CI -0.77~-0.59, P < 0.001; DALYs: EAPC = -0.99, 95% CI -1.09 to -0.89, P < 0.001). Alcohol consumption (R = 0.79, P < 0.001), smoking prevalence (R = 0.75, P < 0.001), and calcium (R = 0.72, P < 0.001) showed a positive correlation with the age-standardized incidence rate (ASIR), whereas classic monsoon region (R = -0.68, P < 0.001) and mean temperature (R = -0.7, P < 0.001) showed a negative correlation with age-standardized incidence rate (ASIR). Besides, medical and healthcare resources presented a positive correlation with ASIR. Meanwhile, similar relationships were found in age-standardized prevalence rate (ASPR), ASDR, and age-standardized DALY rate (ASDALYR).

Conclusion

CAVD displays widely varied spatial distribution around the world, of which high SDI regions have the highest burdens. Age is a powerful factor and hypertension a predominant attributable risk factor. Moreover, controlling blood pressure, avoiding smoking, reducing alcohol consumption, and so on, could effectively reduce the burden of CAVD.

Global Burden and Improvement Gap of Non-Rheumatic Calcific Aortic Valve Disease: 1990-2019 Findings from Global Burden of Disease Study 2019

The aim of this study was to explore the most updated changing trends of non-rheumatic calcific aortic valve disease (nrCAVD) and reveal possible improvements. We analyzed the age-standardized rates (ASRs) of prevalence, incidence, disability-adjusted life-years (DALYs), and mortality trends of nrCAVD from 1990 to 2019 using data from the Global Burden of Disease (GBD) study 2019. The relations between ASRs and socio-demographic index (SDI) were analyzed with Pearson's correlation coefficients. Decomposition and frontier analysis were employed to reveal the contribution proportion of influence factors and regions where improvement can be achieved. In 2019, there were 9.40 million (95% uncertainty interval (UI): 8.07 to 10.89 million) individuals with nrCAVD globally. From 1990 to 2019, the prevalence rate of nrCAVD increased by 155.47% (95% IU: 141.66% to 171.7%), with the largest increase observed in the middle SDI region (821.11%, 95% UI: 709.87% to 944.23%). Globally, there were no significant changes in the mortality rate of nrCAVD (0.37%, 95% UI: -8.85% to 7.99%). The global DALYs decreased by 10.97% (95% UI: -17.94% to -3.46%). The population attributable fraction (PAF) of high systolic blood pressure increased in the population aged 15-49 years, while it declined slightly in population aged 50+ years. Population growth was the main contributing factor to the increased DALYs across the globe (74.73%), while aging was the driving force in the high-SDI region (80.27%). The Netherlands, Finland, Luxembourg, Germany, and Norway could reduce DALY rates of nrCAVD using their socio-demographic resources. According to these results, we revealed that the burden of nrCAVD increased markedly from 1990 to 2019 in high-SDI and high-middle-SDI regions. There was a downward trend in the mortality due to nrCAVD since 2013, which is possibly owing to profound advances in transcatheter aortic valve replacement. Some countries may reduce burdens of nrCAVD using their socio-demographic resources.

Hesperetin, a Promising Dietary Supplement for Preventing the Development of Calcific Aortic Valve Disease

BACKGROUND

No effective therapeutic agents for calcific aortic valve disease (CAVD) are available currently. Dietary supplementation has been proposed as a novel treatment modality for various diseases. As a flavanone, hesperetin is widely abundant in citrus fruits and has been proven to exert protective effects in multiple diseases. However, the role of hesperetin in CAVD remains unclear.

METHODS

Human aortic valve interstitial cells (VICs) were isolated from aortic valve leaflets. A mouse model of aortic valve stenosis was constructed by direct wire injury (DWI). Immunoblotting, immunofluorescence staining, and flow cytometry were used to investigate the roles of sirtuin 7 (Sirt7) and nuclear factor erythroid 2-related factor 2 (Nrf2) in hesperetin-mediated protective effects in VICs.

RESULTS

Hesperetin supplementation protected the mice from wire-injury-induced aortic valve stenosis; in vitro, hesperetin inhibited the lipopolysaccharide (LPS)-induced activation of NF-κB inflammatory cytokine secretion and osteogenic factors expression, reduced ROS production and apoptosis, and abrogated LPS-mediated injury to the mitochondrial membrane potential and the decline in the antioxidant levels in VICs. These benefits of hesperetin may have been obtained by activating Nrf2-ARE signaling, which corrected the dysfunctional mitochondria. Furthermore, we found that hesperetin could directly bind to Sirt7 and that the silencing of Sirt7 decreased the effects of hesperetin in VICs and potently abolished the ability of hesperetin to increase Nrf2 transcriptional activation.

CONCLUSIONS

Our work demonstrates that hesperetin plays protective roles in the aortic valve through the Sirt7-Nrf2-ARE axis; thus, hesperetin might be a potential dietary supplement that could prevent the development of CAVD.

IL6 gene polymorphism association with calcific aortic valve stenosis and influence on serum levels of interleukin-6

Aortic valve stenosis is the most frequent valve disease in developed countries and its prevalence will increase with population aging. There is still no pharmaceutical treatment nor biomarker to determine the susceptibility to develop aortic stenosis. Therefore, we analyzed the association of polymorphisms in risk loci with calcific aortic stenosis. Patients with aortic valve disease were genotyped for PALMD rs6702619, LPA rs10455872, and IL6 rs1800795 polymorphisms and circulating levels of interleukin-6 (IL-6) were measured. Calcium content of leaflets obtained in valve replacement surgeries was determined by micro-computed tomography. In the genotyping of 578 individuals, we found significant association between PALMD and IL6 polymorphisms and aortic stenosis in patients with tricuspid aortic valve, independently of other potentially confounding variables such as age and dyslipidemia. There was no association of these polymorphisms with valve calcium content, but this value correlated with the mean aortic pressure gradient (r = 0.44; P < 0.001). The CC genotype of IL6 polymorphism was associated with higher levels of serum IL-6 compared to other genotypes (23.5 vs. 10.5 pg/ml, respectively; P = 0.029). Therefore, patients carrying the CC genotype of IL6 rs1800795 polymorphism present higher levels of circulating IL-6 and this could contribute to the severity of the aortic valve stenosis. Our results agree with the identification of IL6 as a locus risk for stenosis and also with the intervention of this cytokine in aortic valve calcification. A more exhaustive follow-up of those patients carrying risk genotypes is therefore recommended.

[Optimal time window for observation of calcific aortic valve disease in mice following catheter-induced valve injury]

OBJECTIVE

To investigate the optimal time window for observation of catheter-induced valve injury that mimics calcified aortic valve disease in mice.

METHODS

A catheter was inserted into the right common carotid artery of 8-week-old C57BL6 mice under ultrasound guidance, and aortic valve injury was induced using the guide wire.At 4, 8 and 16 weeks after modeling, the mice were subjected to ultrasound measurement of the heart short axial shortening rate, aortic valve peak velocity and aortic valve orifice area.Grain-Eosin staining was used to observe the changes in the thickness of the aortic valve, and calcium deposition in the aortic valve was assessed using Alizarin red staining.Immunofluorescence assay was performed to detect the expression of alkaline phosphatase (ALP) in the aortic valve.

RESULTS

At 4, 8 and 16 weeks after modeling, valve thickness (P=0.002), calcium deposition (P < 0.0001) and the expression of osteogenic protein ALP (P=0.0016) were significantly increased, but their increments were comparable at the 3 time points of observation.

CONCLUSION

In mouse models of calcific aortic valve disease induced by catheter valve injury, 4 weeks after the injury appears to be the optimal time window for observation of pathophysiological changes in the aortic valves to avoid further increase of the death rate of the mice over time.

Contribution of Oxidative Stress (OS) in Calcific Aortic Valve Disease (CAVD): From Pathophysiology to Therapeutic Targets

Calcific aortic valve disease (CAVD) is a major cause of cardiovascular mortality and morbidity, with increased prevalence and incidence. The underlying mechanisms behind CAVD are complex, and are mainly illustrated by inflammation, mechanical stress (which induces prolonged aortic valve endothelial dysfunction), increased oxidative stress (OS) (which trigger fibrosis), and calcification of valve leaflets. To date, besides aortic valve replacement, there are no specific pharmacological treatments for CAVD. In this review, we describe the mechanisms behind aortic valvular disease, the involvement of OS as a fundamental element in disease progression with predilection in AS, and its two most frequent etiologies (calcific aortic valve disease and bicuspid aortic valve); moreover, we highlight the potential of OS as a future therapeutic target.

The Effect of Osteoprotectin (OPG)/Receptor Activator of Nuclear Factor-κB Ligand (RANKL)/Receptor Activator of Nuclear Factor-κB (RANK) Gene Methylation on Aortic Valve Calcified

To evaluate the effect of the methylation of osteoprotectin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/receptor activator of nuclear factor-κB (RANK) pathway on aortic valve calcification, the aortic valve tissue was collected from 38 aortic stenosis (AS) patients who underwent valve replacement. OPG and RANKL gene methylation, RT-PCR, and ELISA were performed. Hematoxylin-eosin staining (HE), alizarin red-S staining, and immunohistochemically staining of OPG, RANKL, and CD68 were simultaneously performed. The patients were divided into noncalcified group (n = 21) and calcified group (n = 17). The methylation rate of OPG gene in noncalcified group was higher than that in calcified group (P = 0.027). The methylation degree of RANKL gene was generally lower, but the noncalcified group was still higher than that in the calcified group (P = 0.025). RT-PCR analysis showed that the mRNA expression of OPG and RANKL was higher in calcified group than in noncalcified group (P = 0.007 and P = 0.036, respectively), and the mRNA expression was negatively correlated with the gene methylation rate. The protein expression of OPG and RANKL was detected by immunohistochemistry and ELISA, showing significantly increased in calcified group (P = 0.004 and P = 0.042, respectively). Soluble RANKL (sRANKL) in CD68-positive group was significantly different from that in negative group (0.1243 ± 0.0321 vs 0.0984 ± 0.0218 pg/mL, P = 0.007). There was no significant difference in OPG value between positive group (1.9411 ± 0.4554 ng/mL) and negative group (1.8422 ± 0.5218 ng/mL, P = 0.587). In conclusion, the degree of methylation of OPG and RANKL genes may play an important role in regulating valve calcification in AS patients.

Association Between Plasma Lipoprotein Levels and Aortic Valve Calcification Among Patients with Aortic Valve Replacement Surgery: A Retrospective Study

Objective

Calcific aortic valve disease (CAVD) is a prevalent type of valvular heart disease, its association with dyslipidemia remains controversial.

Methods

Of 449 CAVD patients who underwent aortic valve replacement, 228 formed the aortic valve calcification (AVC) group, and 221 were the non-calcification group. We retrospectively reviewed the preoperative and one-year postoperative plasma lipoprotein levels of both and performed a logistic regression to evaluate the factors associated with AVC.

Results

Preoperatively, AVC patients had significantly higher coronary heart disease (43.0% vs 24.9%, p<0.001), peripheral vascular disease (41.7% vs 26.2%, p<0.001), and heart failure rates (63.6% vs 47.1%, p<0.001), and a higher level of total cholesterol (4.1±0.9 vs 3.9±0.8 mmol/L, p=0.032) and very low-density cholesterol (0.6 (0.4–0.7) vs 0.5 (0.3–0.7) mmol/L, p=0.054). Echocardiography revealed a significant difference of aortic stenosis in both AVC and non-AVC groups (p<0.05), and also identified aortic regurgitation (AR) with a significant difference between these two groups (p=0.003). The peak transaortic jet velocity, peak transaortic gradient, and mean transaortic gradient were significantly higher in the calcification group (all p<0.001), but the aortic valve area (0.7 (0.5–1.0) vs 4 (0.9–4.5) cm²; p<0.001) was smaller. Age (OR=1.023), total cholesterol (OR=1.272), and mean transaortic gradient (OR=1.182) were AVC risk factors. A larger aortic valve area (OR=0.010) were protective factors. The one-year mortality and perivalvular leakage rates were significantly higher in the calcification group.

Conclusion

Total cholesterol was significantly higher in AVC patients and may be an AVC risk factor along with age and mean transaortic gradient. AVC patients had a relatively poorer outcome within one year.

The Natural Product Andrographolide Ameliorates Calcific Aortic Valve Disease by Regulating the Proliferation of Valve Interstitial Cells via the MAPK-ERK Pathway

Calcific aortic valve disease (CAVD) is an active pathobiological process that involves fibrosis and calcification of aortic valve leaflets, thereby causing cardiac hemodynamic changes and eventually heart failure. Cell proliferation changes at the initial stage of CAVD are an important target for pharmaceutical intervention. This study aimed to investigate whether andrographolide (AGP) could inhibit the proliferation of valve interstitial cells (VICs) in vitro and in vivo to delay the process of CAVD. Cell proliferative factors were tested in both healthy and CAVD aortic valve samples. Cell cycle, cell growth, and calcification of VICs were assessed using flow cytometry, CCK8 assay, EdU staining, and Alizarin Red S staining. The expression of cell proliferative factors and osteogenic factors were quantified by qRT-PCR or immunofluorescence staining. The interaction between AGP and ERK (extracellular regulated protein kinases) was detected by molecular docking. In addition, a high-fat diet-fed animal model was used to verify the effect of AGP on CAVD in vivo. In conclusion, we found that AGP ameliorates aortic valve incrassation by inhibiting cell proliferation via the MAPK-ERK signaling pathway. Therefore, AGP is a promising drug that prevents the occurrence of CAVD via regulating cell proliferation.

VCAM-1 Targeted Lipopolyplexes as Vehicles for Efficient Delivery of shRNA-Runx2 to Osteoblast-Differentiated Valvular Interstitial Cells; Implications in Calcific Valve Disease Treatment

Calcific aortic valve disease (CAVD) is a progressive inflammatory disorder characterized by extracellular matrix remodeling and valvular interstitial cells (VIC) osteodifferentiation leading to valve leaflets calcification and impairment movement. Runx2, the master transcription factor involved in VIC osteodifferentiation, modulates the expression of other osteogenic molecules. Previously, we have demonstrated that the osteoblastic phenotypic shift of cultured VIC is impeded by Runx2 silencing using fullerene (C60)-polyethyleneimine (PEI)/short hairpin (sh)RNA-Runx2 (shRunx2) polyplexes. Since the use of polyplexes for in vivo delivery is limited by their instability in the plasma and the non-specific tissue interactions, we designed and obtained targeted, lipid-enveloped polyplexes (lipopolyplexes) suitable for (1) systemic administration and (2) targeted delivery of shRunx2 to osteoblast-differentiated VIC (oVIC). Vascular cell adhesion molecule (VCAM)-1 expressed on the surface of oVIC was used as a target, and a peptide with high affinity for VCAM-1 was coupled to the surface of lipopolyplexes encapsulating C60-PEI/shRunx2 (V-LPP/shRunx2). We report here that V-LPP/shRunx2 lipopolyplexes are cyto- and hemo-compatible and specifically taken up by oVIC. These lipopolyplexes are functional as they downregulate the Runx2 gene and protein expression, and their uptake leads to a significant decrease in the expression of osteogenic molecules (OSP, BSP, BMP-2). These results identify V-LPP/shRunx2 as a new, appropriately directed vehicle that could be instrumental in developing novel strategies for blocking the progression of CAVD using a targeted nanomedicine approach.

Bioinformatics and Machine Learning Methods to Identify FN1 as a Novel Biomarker of Aortic Valve Calcification

Aim

The purpose of this study was to identify potential diagnostic markers for aortic valve calcification (AVC) and to investigate the function of immune cell infiltration in this disease.

Methods

The AVC data sets were obtained from the Gene Expression Omnibus. The identification of differentially expressed genes (DEGs) and the performance of functional correlation analysis were carried out using the R software. To explore hub genes related to AVC, a protein–protein interaction network was created. Diagnostic markers for AVC were then screened and verified using the least absolute shrinkage and selection operator, logistic regression, support vector machine-recursive feature elimination algorithms, and hub genes. The infiltration of immune cells into AVC tissues was evaluated using CIBERSORT, and the correlation between diagnostic markers and infiltrating immune cells was analyzed. Finally, the Connectivity Map database was used to forecast the candidate small molecule drugs that might be used as prospective medications to treat AVC.

Results

A total of 337 DEGs were screened. The DEGs that were discovered were mostly related with atherosclerosis and arteriosclerotic cardiovascular disease, according to the analyses. Gene sets involved in the chemokine signaling pathway and cytokine–cytokine receptor interaction were differently active in AVC compared with control. As the diagnostic marker for AVC, fibronectin 1 (FN1) (area the curve = 0.958) was discovered. Immune cell infiltration analysis revealed that the AVC process may be mediated by naïve B cells, memory B cells, plasma cells, activated natural killer cells, monocytes, and macrophages M0. Additionally, FN1 expression was associated with memory B cells, M0 macrophages, activated mast cells, resting mast cells, monocytes, and activated natural killer cells. AVC may be reversed with the use of yohimbic acid, the most promising small molecule discovered so far.

Conclusion

FN1 can be used as a diagnostic marker for AVC. It has been shown that immune cell infiltration is important in the onset and progression of AVC, which may benefit in the improvement of AVC diagnosis and treatment.

Lipoprotein(a) and Body Mass Compound the Risk of Calcific Aortic Valve Disease

BACKGROUND

High plasma lipoprotein(a) and high body mass index are both causal risk factors for calcific aortic valve disease.

OBJECTIVES

This study sought to test the hypothesis that risk of calcific aortic valve disease is the highest when both plasma lipoprotein(a) and body mass index are extremely high.

METHODS

From the Copenhagen General Population Study, we used information on 69,988 randomly selected individuals recruited from 2003 to 2015 (median follow-up 7.4 years) to evaluate the association between high lipoprotein(a) and high body mass index with risk of calcific aortic valve disease.

RESULTS

Compared with individuals in the 1st to 49th percentiles for both lipoprotein(a) and body mass index, the multivariable adjusted HRs for calcific aortic valve disease were 1.6 (95% CI: 1.3-1.9) for the 50th to 89th percentiles of both (16% of all individuals) and 3.5 (95% CI: 2.5-5.1) for the 90th to 100th percentiles of both (1.1%) (P for interaction = 0.92). The 10-year absolute risk of calcific aortic valve disease increased with higher lipoprotein(a), body mass index, and age, and was higher in men than in women. For women and men 70-79 years of age with body mass index ≥30.0 kg/m², 10-year absolute risks were 5% and 8% for lipoprotein(a) ≤42 mg/dL (88 nmol/L), 7% and 11% for 42-79 mg/dL (89-169 nmol/L), and 9% and 14% for lipoprotein(a) ≥80 mg/dL (170 nmol/L), respectively.

CONCLUSIONS

Extremely high lipoprotein(a) levels and extremely high body mass index together conferred a 3.5-fold risk of calcific aortic valve disease. Ten-year absolute risk of calcific aortic valve disease by categories of lipoprotein(a) levels, body mass index, age, and sex ranged from 0.4% to 14%.

Innate immune cells in the pathophysiology of calcific aortic valve disease: lessons to be learned from atherosclerotic cardiovascular disease?

Calcific aortic valve disease (CAVD) is the most common valvular disease in the developed world with currently no effective pharmacological treatment available. CAVD results from a complex, multifactorial process, in which valvular inflammation and fibro-calcific remodelling lead to valve thickening and cardiac outflow obstruction. The exact underlying pathophysiology of CAVD is still not fully understood, yet the development of CAVD shows many similarities with the pathophysiology of atherosclerotic cardiovascular disease (ASCVD), such as coronary artery disease. Innate immune cells play a crucial role in ASCVD and might also play a pivotal role in the development of CAVD. This review summarizes the current knowledge on the role of innate immune cells, both in the circulation and in the aortic valve, in the development of CAVD and the similarities and differences with ASCVD. Trained immunity and clonal haematopoiesis of indeterminate potential are proposed as novel immunological mechanisms that possibly contribute to the pathophysiology of CAVD and new possible treatment targets are discussed.

[Screening analysis of proteolytic enzymes and their inhibitors in the leaflets of epoxy-treated bioprosthetic heart valves explanted due to dysfunction]

Bioprosthetic heart valves (BHVs) are known for their lower thrombogenicity rates and excellent hemodynamic parameters similar to native valves. However, the lifespan of these medical devices is limited to 15 years due to the structural valve degeneration. One of the mechanisms underlying functional impairment and calcification of BHVs includes proteolytic degradation of biomaterials. However, proteases found in xenogeneic BHVs tissue remain poorly studied. In this study using the dot blot assay, we have performed a screening analysis of proteolytic enzymes and their inhibitors in the leaflets of five BHVs explanted due to their dysfunction. Five aortic valves (AVs) explanted due to calcific aortic valve disease were studied as a comparison group. The results of the study have demonstrated that at least 17 proteases and 19 of their inhibitors can be found in BHVs. In the AVs 20 proteases and 21 their inhibitors were identified. Small quantitative differences were noted between proteomic profiles of the BHVs and AVs. Matrix metalloproteinases (MMPs) were expressed in BHVs and AVs at comparable levels, but the level of tissue inhibitors of metalloproteinases-1/-2 and RECK protein in implant tissues was lower than in natural valves. Probably, excessive activity of MMPs cannot be counterbalanced by their inhibitors in BHVs and therefore MMPs can degrade prosthetic biomaterial. Moreover, the detection of a wide range of proteolytic enzymes and their inhibitors in the degenerated BHVs suggests the existence of several pathophysiological pathways that can lead to structural valve degeneration.

Emodin alleviates aortic valvular calcification by inhibiting the AKT/FOXO1 pathway

BACKGROUND

Valvular calcification commonly occurs in elderly individuals, and is increasingly considered an important economic and health burden. However, no efficient drugs against valvular calcification are available. The present work aimed to examine emodin's suppressive effect on high-calcium-dependent valve calcification and explore the underpinning mechanisms.

METHODS

Experiments were carried out in mice receiving vitamin D (Vit D) to induce valvular calcification.

RESULTS

Cell viability and apoptosis assays demonstrated celastrol suppressed proliferation and increased apoptosis in porcine aortic valve interstitial cells (PAVICs) at concentrations higher than 10 μM. Emodin (5 μM) attenuated the upregulation of osteogenic genes as well as calcium accumulation in PAVICs under high-calcium conditions. The elevations of calcium content in serum and valve, and calcium accumulation in valve and artery were suppressed by emodin in mice with valvular calcification after joint treatment with adenine and Vit D. In addition, p-AKT and p-FOXO1 were upregulated in PAVICs under high-calcium conditions, and this effect was reversed by emodin treatment. SC79, an AKT activator, reversed emodin's suppressive effects on increased calcium content, calcium deposition and osteogenic gene expression in PAVICs induced by calcific medium.

CONCLUSIONS

These data demonstrated emodin alleviates high-calcium-associated valvular calcification via AKT/FOXO1 signaling suppression, providing new insights into therapeutic strategies for clinical valvular calcification.

Elevated lipoprotein(a) in mitral and aortic valve calcification and disease: The Copenhagen General Population Study

BACKGROUND AND AIMS

We tested the hypotheses (i) that elevated lipoprotein(a) is causally associated with both mitral and aortic valve calcification and disease, and (ii) that aortic valve calcification mediates the effect of elevated lipoprotein(a) on aortic valve stenosis.

METHODS

From the Copenhagen General Population study, we included 12,006 individuals who underwent cardiac computed tomography to measure mitral and aortic valve calcification and 85,884 to examine risk of heart valve disease. Participants had information on plasma lipoprotein(a) and genetic instruments associated with plasma lipoprotein(a) to investigate potential causality.

RESULTS

At age 70-79 years, 29% and 54% had mitral and aortic valve calcification, respectively. For 10-fold higher lipoprotein(a) levels, multifactorially adjusted odds ratios for mitral and aortic valve calcification were 1.26 (95% confidence interval: 1.13-1.41) and 1.62 (1.48-1.77). For mitral and aortic valve stenosis, corresponding hazard ratios were 0.93 (95%CI:0.40-2.15, 19 events) and 1.54 (1.38-1.71, 1158 events), respectively. For ≤23 versus ≥36 kringle IV type 2 number of repeats, the age and sex adjusted odds ratios for mitral and aortic valve calcification were 1.53 (1.18-1.99) and 2.23 (1.81-2.76). For carriers versus non-carriers of LPA rs10455872, odds ratios for mitral and aortic valve calcification were 1.33 (1.13-1.57) and 1.86 (1.64-2.13). For aortic valve stenosis, 31% (95%CI:16%-76%) of the effect of lipoprotein(a) was mediated through calcification.

CONCLUSIONS

Elevated lipoprotein(a) was genetically and observationally associated with mitral and aortic valve calcification and aortic valve stenosis. Aortic valve calcification mediated 31% of the effect of elevated lipoprotein(a) on aortic valve stenosis.

Tgfβ1-Cthrc1 Signaling Plays an Important Role in the Short-Term Reparative Response to Heart Valve Endothelial Injury

OBJECTIVE

Aortic valve disease is a common worldwide health burden with limited treatment options. Studies have shown that the valve endothelium is critical for structure-function relationships, and disease is associated with its dysfunction, damage, or injury. Therefore, therapeutic targets to maintain a healthy endothelium or repair damaged endothelial cells could hold promise. In this current study, we utilize a surgical mouse model of heart valve endothelial cell injury to study the short-term response at molecular and cellular levels. The goal is to determine if the native heart valve exhibits a reparative response to injury and identify the mechanisms underlying this process. Approach and Results: Mild aortic valve endothelial injury and abrogated function was evoked by inserting a guidewire down the carotid artery of young (3 months) and aging (16-18 months) wild-type mice. Short-term cellular responses were examined at 6 hours, 48 hours, and 4 weeks following injury, whereas molecular profiles were determined after 48 hours by RNA-sequencing. Within 48 hours following endothelial injury, young wild-type mice restore endothelial barrier function in association with increased cell proliferation, and upregulation of transforming growth factor beta 1 (Tgfβ1) and the glycoprotein, collagen triple helix repeat containing 1 (Cthrc1). Interestingly, this beneficial response to injury was not observed in aging mice with known underlying endothelial dysfunction.

CONCLUSIONS

Data from this study suggests that the healthy valve has the capacity to respond to mild endothelial injury, which in short term has beneficial effects on restoring endothelial barrier function through acute activation of the Tgfβ1-Cthrc1 signaling axis and cell proliferation.

A Novel Technique for Preparation, Staining, and Visualization of Tissue with Metal Implants and Extraskeletal Calcification Areas

The aim of the study was to evaluate the efficacy of a novel technique for preparation, staining, and visualization of tissues containing extra-skeletal mineralization areas, all-metal implants or their prototypes for their subsequent examination using scanning electron microscopy in the backscattered electron mode.

Impact of calcific aortic valve disease on valve mechanics

The aortic valve is a highly dynamic structure characterized by a transvalvular flow that is unsteady, pulsatile, and characterized by episodes of forward and reverse flow patterns. Calcific aortic valve disease (CAVD) resulting in compromised valve function and increased pressure overload on the ventricle potentially leading to heart failure if untreated, is the most predominant valve disease. CAVD is a multi-factorial disease involving molecular, tissue and mechanical interactions. In this review, we aim at recapitulating the biomechanical loads on the aortic valve, summarizing the current and most recent research in the field in vitro, in-silico, and in vivo, and offering a clinical perspective on current strategies adopted to mitigate or approach CAVD.

Non-calcific aortic tissue quantified from computed tomography angiography improves diagnosis and prognostication of patients referred for transcatheter aortic valve implantation

AIMS

We aimed to investigate the role of aortic valve tissue composition from quantitative cardiac computed tomography angiography (CTA) in patients with severe aortic stenosis (AS) for the differentiation of disease subtypes and prognostication after transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

Our study included 447 consecutive AS patients from six high-volume centres reporting to a prospective nationwide registry of TAVI procedures (POL-TAVI), who underwent cardiac CTA before TAVI, and 224 matched controls with normal aortic valves. Components of aortic valve tissue were identified using semi-automated software as calcific and non-calcific. Volumes of each tissue component and composition [(tissue component volume/total tissue volume) × 100%] were quantified. Relationship of aortic valve composition with clinical outcomes post-TAVI was evaluated using Valve Academic Research Consortium (VARC)-2 definitions.High-gradient (HG) AS patients had significantly higher aortic tissue volume compared to low-flow low-gradient (LFLG)-AS (1672.7 vs. 1395.3 mm3, P < 0.001) as well as controls (509.9 mm3, P < 0.001), but increased non-calcific tissue was observed in LFLG compared to HG patients (1063.6 vs. 860.2 mm3, P < 0.001). Predictive value of aortic valve calcium score [area under the curve (AUC) 0.989, 95% confidence interval (CI): 0.981-0.996] for severe AS was improved after addition of non-calcific tissue volume (AUC 0.995, 95% CI: 0.991-0.999, P = 0.011). In the multivariable analysis of clinical and quantitative computed tomography parameters of aortic valve tissue, non-calcific tissue volume [odds ratio (OR) 5.2, 95% CI 1.8-15.4, P = 0.003] and history of stroke (OR 2.6, 95% CI 1.1-6.5, P = 0.037) were independent predictors of 30-day major adverse cardiovascular event (MACE).

CONCLUSION

Quantitative CTA assessment of aortic valve tissue volume and composition can improve detection of severe AS, differentiation between HG and LFLG-AS in patients referred for TAVI as well as prediction of 30-day MACEs post-TAVI, over the current clinical standard.

Burden of valvular heart disease, 1990-2017: Results from the Global Burden of Disease Study 2017

Background

Valvular heart disease (VHD) is expected to cause an increase in public-health problems in the coming years, especially in elderly populations. We aim to estimate the incidence, mortality, and burden of VHD, by age, from 1990 to 2017 in 195 countries and territories.

Methods

We estimated the incidence, mortality, and burden of VHD based on the Global Burden of Disease Study 2017. All metrics are presented with their 95% uncertainty intervals (UIs). The Socio-demographic Index was used to identify whether developmental status correlates with health outcomes.

Results

The global incidence of rheumatic heart disease (RHD) decreased by 8.67% between 1990 and 2017, while that of non-rheumatic VHD (NRVHD) increased by 45.10%. There was a 54.00% decrease in age-standardized death rate (ASDR) for RHD, but a small and non-significant decrease (-3.00%) in the ASDR for NRVHD. The global age-standardized disability-adjusted life years (DALY) rate of RHD decreased by 53.52%, while there was a 12.62% reduction in the age-standardized DALY rate of NRVHD.

Conclusions

The burden from different VHDs demonstrated a diverse change at a global level between 1990 and 2017. Although RHD burden has an obvious means of mitigation, a substantially high incidence of NRVHD was observed over this time period, especially in the elderly, which may lead to high health care costs and signify the potential for even higher costs in the future.

Self-eating and Heart: The Emerging Roles of Autophagy in Calcific Aortic Valve Disease

Autophagy is a self-degradative pathway by which subcellular elements are broken down intracellularly to maintain cellular homeostasis. Cardiac autophagy commonly decreases with aging and is accompanied by the accumulation of misfolded proteins and dysfunctional organelles, which are undesirable to the cell. Reduction of autophagy over time leads to aging-related cardiac dysfunction and is inversely related to longevity. However, despite the increasing interest in autophagy in cardiac diseases and aging, the process remains an undervalued and disregarded object in calcific valvular disease. Neither the nature through which autophagy is triggered nor the interplay between autophagic machinery and targeted molecules during aortic valve calcification are fully understood. Recently, the upregulation of autophagy has been shown to result in cardioprotective effects against cell death as well as its origin. Here, we review the evidence that shows how autophagy can be both beneficial and detrimental as it pertains to aortic valve calcification in the heart.

NOTCH Signaling in Aortic Valve Development and Calcific Aortic Valve Disease

NOTCH intercellular signaling mediates the communications between adjacent cells involved in multiple biological processes essential for tissue morphogenesis and homeostasis. The NOTCH1 mutations are the first identified human genetic variants that cause congenital bicuspid aortic valve (BAV) and calcific aortic valve disease (CAVD). Genetic variants affecting other genes in the NOTCH signaling pathway may also contribute to the development of BAV and the pathogenesis of CAVD. While CAVD occurs commonly in the elderly population with tri-leaflet aortic valve, patients with BAV have a high risk of developing CAVD at a young age. This observation indicates an important role of NOTCH signaling in the postnatal homeostasis of the aortic valve, in addition to its prenatal functions during aortic valve development. Over the last decade, animal studies, especially with the mouse models, have revealed detailed information in the developmental etiology of congenital aortic valve defects. In this review, we will discuss the molecular and cellular aspects of aortic valve development and examine the embryonic pathogenesis of BAV. We will focus our discussions on the NOTCH signaling during the endocardial-to-mesenchymal transformation (EMT) and the post-EMT remodeling of the aortic valve. We will further examine the involvement of the NOTCH mutations in the postnatal development of CAVD. We will emphasize the deleterious impact of the embryonic valve defects on the homeostatic mechanisms of the adult aortic valve for the purpose of identifying the potential therapeutic targets for disease intervention.

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

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.

Predicting the Key Genes Involved in Aortic Valve Calcification Through Integrated Bioinformatics Analysis

Background: Valvular heart disease is obtaining growing attention in the cardiovascular field and it is believed that calcific aortic valve disease (CAVD) is the most common valvular heart disease (VHD) in the world. CAVD does not have a fully effective treatment to delay its progression and the specific molecular mechanism of aortic valve calcification remains unclear.

Materials and Methods: We obtained the gene expression datasets GSE12644 and GSE51472 from the public comprehensive free database GEO. Then, a series of bioinformatics methods, such as GO and KEGG analysis, STING online tool, Cytoscape software, were used to identify differentially expressed genes in CAVD and healthy controls, construct a PPI network, and then identify key genes. In addition, immune infiltration analysis was used via CIBERSORT to observe the expression of various immune cells in CAVD.

Results: A total of 144 differential expression genes were identified in the CAVD samples in comparison with the control samples, including 49 up-regulated genes and 95 down-regulated genes. GO analysis of DEGs were most observably enriched in the immune response, signal transduction, inflammatory response, proteolysis, innate immune response, and apoptotic process. The KEGG analysis revealed that the enrichment of DEGs in CAVD were remarkably observed in the chemokine signaling pathway, cytokine-cytokine receptor interaction, and PI3K-Akt signaling pathway. Chemokines CXCL13, CCL19, CCL8, CXCL8, CXCL16, MMP9, CCL18, CXCL5, VCAM1, and PPBP were identified as the hub genes of CAVD. It was macrophages that accounted for the maximal proportion among these immune cells. The expression of macrophages M0, B cells memory, and Plasma cells were higher in the CAVD valves than in healthy valves, however, the expression of B cells naïve, NK cells activated, and macrophages M2 were lower.

Conclusion: We detected that chemokines CXCL13, CXCL8, CXCL16, and CXCL5, and CCL19, CCL8, and CCL18 are the most important markers of aortic valve disease. The regulatory macrophages M0, plasma cells, B cells memory, B cells naïve, NK cells activated, and macrophages M2 are probably related to the occurrence and the advancement of aortic valve stenosis. These identified chemokines and these immune cells may interact with a subtle adjustment relationship in the development of calcification in CAVD.

Changing epidemiology of calcific aortic valve disease: 30-year trends of incidence, prevalence, and deaths across 204 countries and territories

Calcific aortic valve disease (CAVD) is associated with increased morbidity and mortality. We aimed to elucidate the 30-year epidemiology of CAVD globally. Global CAVD incidence, prevalence, and deaths increased 3.51-, 4.43-, and 1.38-fold from 1990 to 2019, respectively, without any decreasing trends, even after age standardization. In 2019, Slovenia had the highest age-standardized rate (ASR) of CAVD incidence (62.21/100,000 persons) and prevalence (1,080.06/100,000) whereas Cyprus had the highest ASR of deaths (8.20/100,000). Population aging was an important contributor to incidence. Compared with women, more men had CAVD and men had earlier peaks in disease prevalence. High systolic blood pressure, diet high in sodium, and lead exposure were the main risk factors for deaths owing to CAVD. The estimated annual percentage change, a measure to estimate the variation of ASR, was significantly associated with the ASR and sociodemographic index (SDI) in 2019 for incidence and prevalence across all 204 countries and territories (all p<0.0001). With increased lifespan and risk factors, the overall burden of CAVD is high and remains on the rise, with differences by sex, age, and SDI level. Our findings serve to sound the alarm for organizations, institutions, and resources whose primary purpose is to improve human health.

Extracellular Matrix in Calcific Aortic Valve Disease: Architecture, Dynamic and Perspectives

Calcific Aortic Valve Disease (CAVD) is the most common valvular heart disease in developed countries and in the ageing population. It is strongly correlated to median age, affecting up to 13% of the population over the age of 65. Pathophysiological analysis indicates CAVD as a result of an active and degenerative disease, starting with sclerosis and chronic inflammation and then leaflet calcification, which ultimately can account for aortic stenosis. Although CAVD has been firstly recognized as a passive event mostly resulting from a degenerative aging process, much evidences suggests that calcification arises from different active processes, involving both aortic valve-resident cells (valve endothelial cells, valve interstitial cells, mesenchymal stem cells, innate immunity cells) and circulating cells (circulating mesenchymal cells, immunity cells). Moreover, a role for the cell-derived "matrix vesicles" and extracellular matrix (ECM) components has also been recognized. The aim of this work is to review the cellular and molecular alterations occurring in aortic valve during CAVD pathogenesis, focusing on the role of ECM in the natural course of the disease.

Current Evidence and Future Perspectives on Pharmacological Treatment of Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS), the most common heart valve disease, is characterized by the slow progressive fibro-calcific remodeling of the valve leaflets, leading to progressive obstruction to the blood flow. CAVS is an increasing health care burden and the development of an effective medical treatment is a major medical need. To date, no effective pharmacological therapies have proven to halt or delay its progression to the severe symptomatic stage and aortic valve replacement represents the only available option to improve clinical outcomes and to increase survival. In the present report, the current knowledge and latest advances in the medical management of patients with CAVS are summarized, placing emphasis on lipid-lowering agents, vasoactive drugs, and anti-calcific treatments. In addition, novel potential therapeutic targets recently identified and currently under investigation are reported.

Ultrastructural Pathology of Atherosclerosis, Calcific Aortic Valve Disease, and Bioprosthetic Heart Valve Degeneration: Commonalities and Differences

Atherosclerosis, calcific aortic valve disease (CAVD), and bioprosthetic heart valve degeneration (alternatively termed structural valve deterioration, SVD) represent three diseases affecting distinct components of the circulatory system and their substitutes, yet sharing multiple risk factors and commonly leading to the extraskeletal calcification. Whereas the histopathology of the mentioned disorders is well-described, their ultrastructural pathology is largely obscure due to the lack of appropriate investigation techniques. Employing an original method for sample preparation and the electron microscopy visualisation of calcified cardiovascular tissues, here we revisited the ultrastructural features of lipid retention, macrophage infiltration, intraplaque/intraleaflet haemorrhage, and calcification which are common or unique for the indicated types of cardiovascular disease. Atherosclerotic plaques were notable for the massive accumulation of lipids in the extracellular matrix (ECM), abundant macrophage content, and pronounced neovascularisation associated with blood leakage and calcium deposition. In contrast, CAVD and SVD generally did not require vasculo- or angiogenesis to occur, instead relying on fatigue-induced ECM degradation and the concurrent migration of immune cells. Unlike native tissues, bioprosthetic heart valves contained numerous specialised macrophages and were not capable of the regeneration that underscores ECM integrity as a pivotal factor for SVD prevention. While atherosclerosis, CAVD, and SVD show similar pathogenesis patterns, these disorders demonstrate considerable ultrastructural differences.

Degeneration of Bioprosthetic Heart Valves: Update 2020

The implantation of bioprosthetic heart valves (BHVs) is increasingly becoming the treatment of choice in patients requiring heart valve replacement surgery. Unlike mechanical heart valves, BHVs are less thrombogenic and exhibit superior hemodynamic properties. However, BHVs are prone to structural valve degeneration (SVD), an unavoidable condition limiting graft durability. Mechanisms underlying SVD are incompletely understood, and early concepts suggesting the purely degenerative nature of this process are now considered oversimplified. Recent studies implicate the host immune response as a major modality of SVD pathogenesis, manifested by a combination of processes phenocopying the long‐term transplant rejection, atherosclerosis, and calcification of native aortic valves. In this review, we summarize and critically analyze relevant studies on (1) SVD triggers and pathogenesis, (2) current approaches to protect BHVs from calcification, (3) obtaining low immunogenic BHV tissue from genetically modified animals, and (4) potential strategies for SVD prevention in the clinical setting.

Secreted Factors From Proinflammatory Macrophages Promote an Osteoblast-Like Phenotype in Valvular Interstitial Cells

OBJECTIVE

Resident valvular interstitial cells (VICs) activate to myofibroblasts during aortic valve stenosis progression, which further promotes fibrosis or even differentiate into osteoblast-like cells that can lead to calcification of valve tissue. Inflammation is a hallmark of aortic valve stenosis, so we aimed to determine proinflammatory cytokines secreted from M1 macrophages that give rise to a transient VIC phenotype that leads to calcification of valve tissue. Approach and Results: We designed hydrogel biomaterials as valve extracellular matrix mimics enabling the culture of VICs in either their quiescent fibroblast or activated myofibroblast phenotype in response to the local matrix stiffness. When VIC fibroblasts and myofibroblasts were treated with conditioned media from THP-1-derived M1 macrophages, we observed robust reduction of αSMA (alpha smooth muscle actin) expression, reduced stress fiber formation, and increased proliferation, suggesting a potent antifibrotic effect. We further identified TNF (tumor necrosis factor)-α and IL (interleukin)-1β as 2 cytokines in M1 media that cause the observed antifibrotic effect. After 7 days of culture in M1 conditioned media, VICs began differentiating into osteoblast-like cells, as measured by increased expression of RUNX2 (runt-related transcription factor 2) and osteopontin. We also identified and validated IL-6 as a critical mediator of the observed pro-osteogenic effect.

CONCLUSIONS

Proinflammatory cytokines in M1 conditioned media inhibit myofibroblast activation in VICs (eg, TNF-α and IL-1β) and promote their osteogenic differentiation (eg, IL-6). Together, our work suggests inflammatory M1 macrophages may drive a myofibroblast-to-osteogenic intermediate VIC phenotype, which may mediate the switch from fibrosis to calcification during aortic valve stenosis progression.

Bicuspid Aortic Valve and Endothelial Dysfunction: Current Evidence and Potential Therapeutic Targets

Bicuspid aortic valve (BAV), the most frequent congenital heart malformation, is characterized by the presence of a two-leaflet aortic valve instead of a three-leaflet one. BAV disease progression is associated with valvular dysfunction (in the form of stenosis or regurgitation) and aortopathy, which can lead to aneurysm and aortic dissection. This morphological abnormality modifies valve dynamics and promotes eccentric blood flow, which gives rise to alterations of the flow pattern and wall shear stress (WSS) of the ascending aorta. Recently, evidence of endothelial dysfunction (ED) in BAV disease has emerged. Different studies have addressed a reduced endothelial functionality by analyzing various molecular biomarkers and cellular parameters in BAV patients. Some authors have found impaired functionality of circulating endothelial progenitors in these patients, associating it with valvular dysfunction and aortic dilation. Others focused on systemic endothelial function by measuring artery flow-mediated dilation (FMD), showing a reduced FMD in BAV individuals. Novel biomarkers like increased endothelial microparticles (EMP), which are related to ED, have also been discovered in BAV patients. Finally, latest studies indicate that in BAV, endothelial-to-mesenchymal transition (EndoMT) may also be de-regulated, which could be caused by genetic, hemodynamic alterations, or both. Different hypothesis about the pathology of ED in BAV are nowadays being debated. Some authors blamed this impaired functionality just on genetic abnormalities, which could lead to a pathological aorta. Nevertheless, thanks to the development of new and high-resolution imaging techniques like 4D flow MRI, hemodynamics has gained great attention. Based on latest studies, alterations in blood flow seem to cause proper modification of the endothelial cells (ECs) function and morphology. It also seems to be associated with aortic dilation and decreased vasodilators expression, like nitric oxide (NO). Although nowadays ED in BAV has been reported by many, it is not clear which its main cause may be. Comprehending the pathways that promote ED and its relevance in BAV could help further understand and maybe prevent the serious consequences of this disease. This review will discuss the ED present in BAV, focusing on the latest evidence, biomarkers for ED and potential therapeutic targets (Figure 1).

Hydrogen sulfide inhibits aortic valve calcification in heart via regulating RUNX2 by NF-κB, a link between inflammation and mineralization

Introduction

Hydrogen sulfide (H₂S) was revealed to inhibit aortic valve calcification and inflammation was implicated in the pathogenesis of calcific aortic valve disease (CAVD).

Objectives

We investigate whether H₂S inhibits mineralization via abolishing inflammation.

Methods and results

Expression of pro-inflammatory cytokines, interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) were increased in patients with CAVD and in calcified aortic valve of ApoE-/- mice. Administration of H_{2 2}S releasing donor (4-methoxyphenyl piperidinylphosphinodithioc acid (AP72)) exhibited inhibition on both calcification and inflammation in aortic valve of apolipoprotein E knockout mice (ApoE-/-) mice is reflected by lowering IL-1β and TNF-α levels. Accordingly, AP72 prevented the accumulation of extracellular calcium deposition and decreased nuclear translocation of nuclear factor-κB (NF-κB) in human valvular interstitial cells (VIC). This was also accompanied by reduced cytokine response. Double-silencing of endogenous H₂S producing enzymes, Cystathionine gamma-lyase (CSE) and Cystathionine beta-synthase (CBS) in VIC exerted enhanced mineralization and higher levels of IL-1β and TNF-α. Importantly, silencing NF-κB gene or its pharmacological inhibition prevented nuclear translocation of runt-related transcription factor 2 (Runx2) and subsequently the calcification of human VIC. Increased levels of NF-κB and Runx2 and their nuclear accumulation occurred in ApoE-/- mice with a high-fat diet. Administration of AP72 decreased the expression of NF-κB and prevented its nuclear translocation in VIC of ApoE-/- mice on a high-fat diet, and that was accompanied by a lowered pro-inflammatory cytokine level. Similarly, activation of Runx2 did not occur in VIC of ApoE-/- mice treated with H₂S donor. Employing Stimulated Emission Depletion (STED) nanoscopy, a strong colocalization of NF-κB and Runx2 was detected during the progression of valvular calcification.

Conclusions

Hydrogen sulfide inhibits inflammation and calcification of aortic valve. Our study suggests that the regulation of Runx2 by hydrogen sulfide (CSE/CBS) occurs via NF-κB establishing a link between inflammation and mineralization in vascular calcification.