Molecular imaging insights into early inflammatory stages of arterial and aortic valve calcification

Smooth muscle NF90 deficiency ameliorates diabetic atherosclerotic calcification in male mice via FBXW7-AGER1-AGEs axis

Hyperglycemia accelerates calcification of atherosclerotic plaques in diabetic patients, and the accumulation of advanced glycation end products (AGEs) is closely related to the atherosclerotic calcification. Here, we show that hyperglycemia-mediated AGEs markedly increase vascular smooth muscle cells (VSMCs) NF90/110 activation in male diabetic patients with atherosclerotic calcified samples. VSMC-specific NF90/110 knockout in male mice decreases obviously AGEs-induced atherosclerotic calcification, along with the inhibitions of VSMC phenotypic changes to osteoblast-like cells, apoptosis, and matrix vesicle release. Mechanistically, AGEs increase the activity of NF90, which then enhances ubiquitination and degradation of AGE receptor 1 (AGER1) by stabilizing the mRNA of E3 ubiquitin ligase FBXW7, thus causing the accumulation of more AGEs and atherosclerotic calcification. Collectively, our study demonstrates the effects of VSMC NF90 in mediating the metabolic imbalance of AGEs to accelerate diabetic atherosclerotic calcification. Therefore, inhibition of VSMC NF90 may be a potential therapeutic target for diabetic atherosclerotic calcification.

Morusin Alleviates Aortic Valve Calcification by Inhibiting Valve Interstitial Cell Senescence Through Ccnd1/Trim25/Nrf2 Axis

The senescence of aortic valve interstitial cells (VICs) plays a critical role in the progression of calcific aortic valve disease (CAVD). However, the precise mechanisms underlying the senescence of VICs remain unclear, demanding the identification of a novel target to mitigate this process. Previous studies have highlighted the anti-aging potential of morusin. Thus, this study aimed to explore the therapeutic potential of morusin in CAVD. Cellular experiments reveal that morusin effectively suppresses cellular senescence and cause a shift toward osteogenic differentiation of VICs in vitro. Mechanistically, morusin activate the Nrf2-mediated antiaging signaling pathway by downregulating CCND1 expression and aiding Keap1 degradation through Trim 25. This activation lead to the upregulated expression of antioxidant genes, thus reducing reactive oxygen species production and thereby preventing VIC osteogenic differentiation. In vivo experiments in ApoE-/- mice on a high-fat Western diet demonstrate the positive effect of morusin in mitigating aortic valve calcification. These findings emphasize the antiaging properties of morusin and its potential as a therapeutic agent for CAVD.

The interplay of collagen, macrophages, and microcalcification in atherosclerotic plaque cap rupture mechanics

The rupture of an atherosclerotic plaque cap overlying a lipid pool and/or necrotic core can lead to thrombotic cardiovascular events. In essence, the rupture of the plaque cap is a mechanical event, which occurs when the local stress exceeds the local tissue strength. However, due to inter- and intra-cap heterogeneity, the resulting ultimate cap strength varies, causing proper assessment of the plaque at risk of rupture to be lacking. Important players involved in tissue strength include the load-bearing collagenous matrix, macrophages, as major promoters of extracellular matrix degradation, and microcalcifications, deposits that can exacerbate local stress, increasing tissue propensity for rupture. This review summarizes the role of these components individually in tissue mechanics, along with the interplay between them. We argue that to be able to improve risk assessment, a better understanding of the effect of these individual components, as well as their reciprocal relationships on cap mechanics, is required. Finally, we discuss potential future steps, including a holistic multidisciplinary approach, multifactorial 3D in vitro model systems, and advancements in imaging techniques. The obtained knowledge will ultimately serve as input to help diagnose, prevent, and treat atherosclerotic cap rupture.

Multimodal Analytical Tools to Enhance Mechanistic Understanding of Aortic Valve Calcification

This review focuses on technologies at the core of calcific aortic valve disease (CAVD) and drug target research advancement, including transcriptomics, proteomics, and molecular imaging. We examine how bulk RNA sequencing and single-cell RNA sequencing have engendered organismal genomes and transcriptomes, promoting the analysis of tissue gene expression profiles and cell subpopulations, respectively. We bring into focus how the field is also largely influenced by increasingly accessible proteome profiling techniques. In unison, global transcriptional and protein expression analyses allow for increased understanding of cellular behavior and pathogenic pathways under pathologic stimuli including stress, inflammation, low-density lipoprotein accumulation, increased calcium and phosphate levels, and vascular injury. We also look at how direct investigation of protein signatures paves the way for identification of targetable pathways for pharmacologic intervention. Here, we note that imaging techniques, once a clinical diagnostic tool for late-stage CAVD, have since been refined to address a clinical need to identify microcalcifications using positron emission tomography/computed tomography and even detect in vivo cellular events indicative of early stage CAVD and map the expression of identified proteins in animal models. Together, these techniques generate a holistic approach to CAVD investigation, with the potential to identify additional novel regulatory pathways.

Associations between pan-immune-inflammation value and abdominal aortic calcification: a cross-sectional study

Background

Abdominal aortic calcification (AAC) pathogenesis is intricately linked with inflammation. The pan-immune-inflammation value (PIV) emerges as a potential biomarker, offering reflection into systemic inflammatory states and assisting in the prognosis of diverse diseases. This research aimed to explore the association between PIV and AAC.

Methods

Employing data from the National Health and Nutrition Examination Survey (NHANES), this cross-sectional analysis harnessed weighted multivariable regression models to ascertain the relationship between PIV and AAC. Trend tests probed the evolving relationship among PIV quartiles and AAC. The study also incorporated subgroup analysis and interaction tests to determine associations within specific subpopulations. Additionally, the least absolute shrinkage and selection operator (LASSO) regression and multivariable logistic regression were used for characteristics selection to construct prediction model. Nomograms were used for visualization. The receiver operator characteristic (ROC) curve, calibration plot and decision curve analysis were applied for evaluate the predictive performance.

Results

From the cohort of 3,047 participants, a distinct positive correlation was observed between PIV and AAC. Subsequent to full adjustments, a 100-unit increment in PIV linked to an elevation of 0.055 points in the AAC score (β=0.055, 95% CI: 0.014-0.095). Categorizing PIV into quartiles revealed an ascending trend: as PIV quartiles increased, AAC scores surged (β values in Quartile 2, Quartile 3, and Quartile 4: 0.122, 0.437, and 0.658 respectively; P for trend <0.001). Concurrently, a marked rise in SAAC prevalence was noted (OR values for Quartile 2, Quartile 3, and Quartile 4: 1.635, 1.842, and 2.572 respectively; P for trend <0.01). Individuals aged 60 or above and those with a history of diabetes exhibited a heightened association. After characteristic selection, models for predicting AAC and SAAC were constructed respectively. The AUC of AAC model was 0.74 (95%CI=0.71-0.77) and the AUC of SAAC model was 0.84 (95%CI=0.80-0.87). According to the results of calibration plots and DCA, two models showed high accuracy and clinical benefit.

Conclusion

The research findings illuminate the potential correlation between elevated PIV and AAC presence. Our models indicate the potential utility of PIV combined with other simple predictors in the assessment and management of individuals with AAC.

Severity of Mitral Valve Stenosis - Possible Relationships With Blood Oxidant Markers and Antioxidants

BACKGROUND

This study examined whether the severity of mitral valve stenosis (MVS) is associated with oxidative stress (OS) markers in the blood, and other hematological and clinicodemographic parameters.Methods and Results: This prospective study was conducted between March and May 2022. Seventy-five patients with newly diagnosed MVS (25 mild, 25 moderate, 25 severe) were included. Mild, moderate, and severe MVS was defined as MV area >2, 1.5-2, and <1.5 cm2, respectively. Various OS markers and laboratory parameters were determined in venous blood samples. For predictive analyses, 2 different analyses were performed to detect patients with severe MVS and those with moderate or severe (moderate/severe) MVS. Age (P=0.388) and sex (P=0.372) distribution were similar in the 3 groups. Multiple logistic regression analysis revealed that a high white blood cell (WBC) count (P=0.023) and high malondialdehyde (P=0.010), superoxide dismutase (SOD; P=0.008), and advanced oxidation protein products (AOPP; P=0.007) levels were independently associated with severe MVS. A low platelet count (P=0.030) and high malondialdehyde (P=0.018), SOD (P=0.008), and AOPP (P=0.001) levels were independently associated with having moderate/severe MVS. The best discriminatory factors for severe MVS were SOD (cut-off >315.5 ng/mL) and glutathione (cut-off >4.7 μmol/L).

CONCLUSIONS

MVS severity seems to be affected by oxidant markers (malondialdehyde and AOPP), antioxidant enzymes (SOD), and inflammation-related cells (WBC and platelets). Future studies are needed to examine these relationships in larger populations.

Nuclear magnetic resonance spectroscopy to quantify major extracellular matrix components in fibro-calcific aortic valve disease

Fibro-calcific aortic valve disease (FCAVD) is a pathological condition marked by overt fibrous and calcific extracellular matrix (ECM) accumulation that leads to valvular dysfunction and left ventricular outflow obstruction. Costly valve implantation is the only approved therapy. Multiple pharmacological interventions are under clinical investigation, however, none has proven clinically beneficial. This failure of translational approaches indicates incomplete understanding of the underlying pathomechanisms and may result from a limited toolbox of scientific methods to assess the cornerstones of FCAVD: lipid deposition, fibrous and calcific ECM accumulation. In this study, we evaluated magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy to both, qualitatively and quantitatively assess these key elements of FCAVD pathogenesis. NMR spectra showed collagen, elastin, triacylglycerols, and phospholipids in human control and FCAVD tissue samples (n = 5). Calcification, measured by the hydroxyapatite content, was detectable in FCAVD tissues and in valve interstitial cells under procalcifying media conditions. Hydroxyapatite was significantly higher in FCAVD tissues than in controls (p < 0.05) as measured by 31P MAS NMR. The relative collagen content was lower in FCAVD tissues vs. controls (p < 0.05). Overall, we demonstrate the versatility of NMR spectroscopy as a diagnostic tool in preclinical FCAVD assessment.

The Role of Endoplasmic Reticulum Stress in Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD), which is involved in osteogenic reprogramming of valvular interstitial cells, is the most common form of valve disease. It still lacks effective pharmacologic intervention, as its cellular biological mechanisms remain unclear. Congenital abnormality (bicuspid valve) and older age are considered to be the most powerful risk factors for CAVD. Aortic valve sclerosis (AVS) and calcific aortic stenosis (CAS), 2 subclinical forms of CAVD, represent 2 distinct stages of aortic valve calcification. During the AVS stage, the disease is characterised by endothelial activation/damage, inflammatory response, and lipid infiltration accompanied by microcalcification. The CAS stage is dominated by calcification, resulting in valvular dysfunction and severe obstruction to cardiac outflow, which is life threatening if surgery is not performed in time. Endoplasmic reticulum (ER) stress, a state in which conditions disrupting ER homeostasis cause an accumulation of unfolded and misfolded proteins in the ER lumen, has been shown to promote osteogenic differentiation and aortic valve calcification. Therefore, identifying targets or drugs for suppressing ER stress may be a novel approach for CAVD treatment.

Vascular calcification: from the perspective of crosstalk

Vascular calcification (VC) is highly correlated with cardiovascular disease morbidity and mortality, but anti-VC treatment remains an area to be tackled due to the ill-defined molecular mechanisms. Regardless of the type of VC, it does not depend on a single cell but involves multi-cells/organs to form a complex cellular communication network through the vascular microenvironment to participate in the occurrence and development of VC. Therefore, focusing only on the direct effect of pathological factors on vascular smooth muscle cells (VSMCs) tends to overlook the combined effect of other cells and VSMCs, including VSMCs-VSMCs, ECs-VMSCs, Macrophages-VSMCs, etc. Extracellular vesicles (EVs) are a collective term for tiny vesicles with a membrane structure that are actively secreted by cells, and almost all cells secrete EVs. EVs docked on the surface of receptor cells can directly mediate signal transduction or transfer their contents into the cell to elicit a functional response from the receptor cells. They have been proven to participate in the VC process and have also shown attractive therapeutic prospects. Based on the advantages of EVs and the ability to be detected in body fluids, they may become a novel therapeutic agent, drug delivery vehicle, diagnostic and prognostic biomarker, and potential therapeutic target in the future. This review focuses on the new insight into VC molecular mechanisms from the perspective of crosstalk, summarizes how multi-cells/organs interactions communicate via EVs to regulate VC and the emerging potential of EVs as therapeutic methods in VC. We also summarize preclinical experiments on crosstalk-based and the current state of clinical studies on VC-related measures.

Influence of diabetes mellitus on the pathological profile of aortic stenosis: a sex-based approach

BACKGROUND

Diabetes mellitus (DM) accelerates the progression of aortic stenosis (AS), but how their underlying molecular mechanisms interact is not clear. Moreover, whether DM contributes to clinically relevant sex-differences in AS is unknown. In this work we aim to characterize the sex-specific profile of major pathological mechanisms fundamental to aortic valve (AV) degeneration in AS patients with or without concomitant DM.

METHODS

283 patients with severe AS undergoing surgical valve replacement (27.6% DM, 59.4% men) were recruited. Expression of pathological markers related to AS were thoroughly assessed in AVs and valve interstitial cells (VICs) according to sex and presence of DM. Complementary in vitro experiments in VICs in the presence of high-glucose levels (25 mM) for 24, 48 and 72 h were performed.

RESULTS

Oxidative stress and metabolic dysfunction markers were increased in AVs from diabetic AS patients compared to non-diabetic patients in both sexes. However, disbalanced oxidative stress and enhanced inflammation were more predominant in AVs from male AS diabetic patients. Osteogenic markers were exclusively increased in the AVs of diabetic women. Basal characterization of VICs confirmed that oxidative stress, inflammation, calcification, and metabolic alteration profiles were increased in diabetic VICs with sex-specific differences. VICs cultured in hyperglycemic-like conditions triggered inflammatory responses in men, whereas in women rapid and higher production of pro-osteogenic molecules.

CONCLUSIONS

DM produces sex-specific pathological phenotypes in AV of AS patients. Importantly, women with diabetes are more prone to develop AV calcification. DM should be considered as a risk factor in AS especially in women.

Lp(a) in the Pathogenesis of Aortic Stenosis and Approach to Therapy with Antisense Oligonucleotides or Short Interfering RNA

To date, no medical therapy can slow the progression of aortic stenosis. Fibrocalcific stenosis is the most frequent form in the general population and affects about 6% of the elderly population. Over the years, diagnosis has evolved thanks to echocardiography and computed tomography assessments. The application of artificial intelligence to electrocardiography could further implement early diagnosis. Patients with severe aortic stenosis, especially symptomatic patients, have valve repair as their only therapeutic option by surgical or percutaneous technique (TAVI). The discovery that the pathogenetic mechanism of aortic stenosis is similar to the atherosclerosis process has made it possible to evaluate the hypothesis of medical therapy for aortic stenosis. Several drugs have been tested to reduce low-density lipoprotein (LDL) and lipoprotein(a) (Lp(a)) levels, inflammation, and calcification. The Proprotein Convertase Subtilisin/Kexin type 9 inhibitors (PCSK9-i) could decrease the progression of aortic stenosis and the requirement for valve implantation. Great interest is related to circulating Lp(a) levels as causally linked to degenerative aortic stenosis. New therapies with ASO (antisense oligonucleotides) and siRNA (small interfering RNA) are currently being tested. Olpasiran and pelacarsen reduce circulating Lp(a) levels by 85-90%. Phase 3 studies are underway to evaluate the effect of these drugs on cardiovascular events (cardiovascular death, non-fatal myocardial injury, and non-fatal stroke) in patients with elevated Lp(a) and CVD (cardiovascular diseases). For instance, if a reduction in Lp(a) levels is associated with aortic stenosis prevention or progression, further prospective clinical trials are warranted to confirm this observation in this high-risk population.

Characterization of plaque phenotypes exhibiting an elevated pericoronary adipose tissue attenuation: insights from the REASSURE-NIRS registry

Inflammation has been considered to promote atheroma instability. Coronary computed tomography angiography (CCTA) visualizes pericoronary adipose tissue (PCAT) attenuation, which reflects coronary artery inflammation. While PCAT attenuation has been reported to predict future coronary events, plaque phenotypes exhibiting high PCAT attenuation remains to be fully elucidated. The current study aims to characterize coronary atheroma with a greater vascular inflammation. We retrospectively analyzed culprit lesions in 69 CAD patients receiving PCI from the REASSURE-NIRS registry (NCT04864171). Culprit lesions were evaluated by both CCTA and near-infrared spectroscopy/intravascular ultrasound (NIRS/IVUS) imaging prior to PCI. PCAT attenuation at proximal RCA (PCATRCA) and NIRS/IVUS-derived plaque measures were compared in patients with PCATRCA attenuation ≥ and < -78.3 HU (median). Lesions with PCATRCA attenuation ≥ -78.3 HU exhibited a greater frequency of maxLCBI4mm ≥ 400 (66% vs. 26%, p < 0.01), plaque burden ≥ 70% (94% vs. 74%, p = 0.02) and spotty calcification (49% vs. 6%, p < 0.01). Whereas positive remodeling (63% vs. 41%, p = 0.07) did not differ between two groups. On multivariable analysis, maxLCBI4mm ≥ 400 (OR = 4.07; 95%CI 1.12-14.74, p = 0.03), plaque burden ≥ 70% (OR = 7.87; 95%CI 1.01-61.26, p = 0.04), and spotty calcification (OR = 14.33; 95%CI 2.37-86.73, p < 0.01) independently predicted high PCATRCA attenuation. Of note, while the presence of only one plaque feature did not necessarily elevate PCATRCA attenuation (p = 0.22), lesions harboring two or more features were significantly associated with higher PCATRCA attenuation. More vulnerable plaque phenotypes were observed in patients with high PCATRCA attenuation. Our findings suggest PCATRCA attenuation as the presence of profound disease substrate, which potentially benefits from anti-inflammatory agents.

Predicting key gene related to immune infiltration and myofibroblast-like valve interstitial cells in patients with calcified aortic valve disease based on bioinformatics analysis

BACKGROUND

Calcified aortic valve disease (CAVD) is the most prevalent valvular disease that can be treated only through valve replacement. We aimed to explore potential biomarkers and the role of immune cell infiltration in CAVD progression through bioinformatics analysis.

METHODS

Differentially ex-pressed genes (DEGs) were screened out based on three microarray datasets: GSE12644, GSE51472 and GSE83453. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to evaluate gene expression differences. Machine learning algorithms and DEGs were used to screen key gene. We used CIBERSORT to evaluate the immune cell infiltration of CAVD and evaluated the correlation between the biomarkers and infiltrating immune cells. We also compared bioinformatics analysis results with the valve interstitial cells (VICs) gene expression in single-cell RNA sequencing.

RESULTS

Collagen triple helix repeat containing 1 (CTHRC1) was identified as the key gene of CAVD. We identified a cell subtype valve interstitial cells-fibroblast, which was closely associated with fibro-calcific progress of aortic valve. CTHRC1 highly expressed in the VIC subpopulation. Immune infiltration analysis demonstrated that mast cells, B cells, dendritic cells and eosinophils were involved in pathogenesis of CAVD. Correlation analysis demonstrated that CTHRC1 was correlated with mast cells mostly.

CONCLUSIONS

In summary, the study suggested that CTHRC1 was a key gene of CAVD and CTHRC1 might participate in the potential molecular pathways involved in the connection between infiltrating immune cells and myofibroblast phenotype VICs.

Pro-Calcifying Role of Enzymatically Modified LDL (eLDL) in Aortic Valve Sclerosis via Induction of IL-6 and IL-33

One of the contributors to atherogenesis is enzymatically modified LDL (eLDL). eLDL was detected in all stages of aortic valve sclerosis and was demonstrated to trigger the activation of p38 mitogen-activated protein kinase (p38 MAPK), which has been identified as a pro-inflammatory protein in atherosclerosis. In this study, we investigated the influence of eLDL on IL-6 and IL-33 induction, and also the impact of eLDL on calcification in aortic valve stenosis (AS). eLDL upregulated phosphate-induced calcification in valvular interstitial cells (VICs)/myofibroblasts isolated from diseased aortic valves, as demonstrated by alizarin red staining. Functional studies demonstrated activation of p38 MAPK as well as an altered gene expression of osteogenic genes known to be involved in vascular calcification. In parallel with the activation of p38 MAPK, eLDL also induced upregulation of the cytokines IL-6 and IL-33. The results suggest a pro-calcifying role of eLDL in AS via induction of IL-6 and IL-33.

Human and porcine aortic valve endothelial and interstitial cell isolation and characterization

Background

Calcific aortic valve stenosis (AVS) is defined by pathological changes in the aortic valve (AV) and their predominant cell types: valvular interstitial (VICs) and endothelial cells (VECs). Understanding the cellular and molecular mechanisms of this disease is a prerequisite to identify potential pharmacological treatment strategies. In this study, we present a unique aortic valve cell isolation technique to acquire specific human and porcine cell populations and compared VICs and VECs of these species with each other for the first time.

Methods

AV cells were isolated from tissue obtained from human patients undergoing surgical aortic valve replacement (SAVR) or from porcine hearts. Functional analysis and in vitro experiments revealed that endothelial-to-mesenchymal transition (EndMT) can be induced in hVECs, leading to a significant increase in mesenchymal markers. In vitro calcification experiments of VICs demonstrated pronounced expression of calcification markers and visible calcific deposits in Alizarin Red staining in both species after incubation with pro-calcific media.

Results

Cells isolated from patient-derived AVs showed mesenchymal and endothelial-specific gene signatures (VIC and VEC, respectively). For instance, von Willebrand factor (vWF) and platelet endothelial adhesion molecule-1 (PECAM1) were upregulated in VECs, while the myofibroblastic markers alpha-smooth muscle actin (α-SMA) and vimentin (VIM) were downregulated in VECs compared to VICs. Analysis of cell function by migration revealed that VECs are more migratory than VICs. Induction of EndMT in vitro in VECs displayed increased expression of EndMT markers and decreased expression of endothelial markers, confirming their mesenchymal transdifferentiation ability. In vitro calcification of VICs revealed upregulation of alkaline phosphatase (ALPL), a hallmark of calcification. In addition, other calcification-related genes such as osteocalcin (BGLAP) and runt-related factor 2 (RUNX2) were upregulated. Alizarin red staining of calcified cells provided a further layer of confirmation that the isolated cells were VICs with osteoblastic differentiation capacity.

Conclusion

This study aims to take a first step towards standardizing a reproducible isolation technique for specific human and porcine VEC and VIC populations. A comparison of human and porcine aortic valve cells demonstrated that porcine cells may serve as an alternative cellular model system in settings where human tissue is difficult to obtain.

High resolution monitoring of valvular interstitial cell driven pathomechanisms in procalcific environment using label-free impedance spectroscopy

Introduction

Fibro-calcific aortic valve disease has high prevalence and is associated with significant mortality. Fibrotic extracellular matrix (ECM) remodeling and calcific mineral deposition change the valvular microarchitecture and deteriorate valvular function. Valvular interstitial cells (VICs) in profibrotic or procalcifying environment are frequently used in vitro models. However, remodeling processes take several days to weeks to develop, even in vitro. Continuous monitoring by real-time impedance spectroscopy (EIS) may reveal new insights into this process.

Methods

VIC-driven ECM remodeling stimulated by procalcifying (PM) or profibrotic medium (FM) was monitored by label-free EIS. Collagen secretion, matrix mineralization, viability, mitochondrial damage, myofibroblastic gene expression and cytoskeletal alterations were analyzed.

Results and Discussion

EIS profiles of VICs in control medium (CM) and FM were comparable. PM reproducibly induced a specific, biphasic EIS profile. Phase 1 showed an initial impedance drop, which moderately correlated with decreasing collagen secretion (r = 0.67, p = 0.22), accompanied by mitochondrial membrane hyperpolarization and cell death. Phase 2 EIS signal increase was positively correlated with augmented ECM mineralization (r = 0.97, p = 0.008). VICs in PM decreased myofibroblastic gene expression (p < 0.001) and stress fiber assembly compared to CM. EIS revealed sex-specific differences. Male VICs showed higher proliferation and in PM EIS decrease in phase 1 was significantly pronounced compared to female VICs (male minimum: 7.4 ± 4.2%, female minimum: 26.5 ± 4.4%, p < 0.01). VICs in PM reproduced disease characteristics in vitro remarkably fast with significant impact of donor sex. PM suppressed myofibroblastogenesis and favored ECM mineralization. In summary, EIS represents an efficient, easy-to-use, high-content screening tool enabling patient-specific, subgroup- and temporal resolution.

Advanced Cardiac Imaging in the Assessment of Aortic Stenosis

Aortic stenosis is the most common form of valve disease in the Western world and a major healthcare burden. Although echocardiography remains the central modality for the diagnosis and assessment of aortic stenosis, recently, advanced cardiac imaging with cardiovascular magnetic resonance, computed tomography, and positron emission tomography have provided invaluable pathological insights that may guide the personalized management of the disease. In this review, we discuss applications of these novel non-invasive imaging modalities for establishing the diagnosis, monitoring disease progression, and eventually planning the invasive treatment of aortic stenosis.

Identification of TNFα-mediated inflammation as potential pathological marker and therapeutic target for calcification progress of congenital bicuspid aortic valve

BACKGROUD

Congenital bicuspid aortic valve (cBAV) develops calcification and stenotic obstruction early compared with degenerative tricuspid aortic valve (dTAV), which requires surgical intervention. Here we report a comparative study of patients with cBAV or dTAV to identify risk factors associated with the rapid development of calcified bicuspid valves.

METHODS

A total of 69 aortic valves (24 dTAV and 45 cBAV) were collected at the time of surgical aortic valve replacement for comparative clinical characteristics. Ten samples were randomly selected from each group for histology, pathology, and inflammatory factors expression and comparison analyses. OM-induced calcification in porcine aortic valve interstitial cell cultures were prepared for illustrating the underlying molecular mechanisms about calcification progress of cBAV and dTAV.

RESULTS

We found that cBAV patients have increased cases of aortic valve stenosis compared with dTAV patients. Histopathological examinations revealed increased collagens deposition, neovascularization and infiltrations by inflammatory cells, especially T-lymphocytes and macrophages. We identified that tumor necrosis factor α (TNFα) and its regulated inflammatory cytokines are upregulated in cBAV. Further in vitro study indicated that TNFα-NFκB and TNFα-GSK3β pathway accelerate aortic valve interstitial cells calcification, while inhibition of TNFα significantly delays this process.

CONCLUSION

The finding of intensified TNFα-mediated inflammation in the pathological cBAV advocates the inhibition of TNFα as a potential treatment for patients with cBAV by alleviating the progress of inflammation-induced valve damage and calcification.

Emerging roles of macrophages in heart failure and associated treatment approaches

Heart failure is typically caused by different cardiovascular conditions and has a poor prognosis. Despite the advances in treatment in recent decades, heart failure has remained a major cause of morbidity and mortality worldwide. As revealed by in vivo and in vitro experiments, inflammation plays a crucial role in adverse cardiac remodeling, ultimately leading to heart failure. Macrophages are central to the innate immune system, and they are the most indispensable cell type for all cardiac injuries and remodeling stages. The immediate microenvironment regulates their polarization and secretion. In this review, we summarize the phenotypic heterogeneity and governing roles of macrophages in the infarcted, inflamed, and aging heart and assess their significance as potential therapeutic targets in heart failure. We also highlight the current missing links and major challenges in the field that remain to be addressed before macrophages can be exploited for therapeutic applications.

Inflammation, Microcalcification, and Increased Expression of Osteopontin Are Histological Hallmarks of Plaque Vulnerability in Patients with Advanced Carotid Artery Stenosis

Background: severe carotid artery stenosis is a major cause of ischemic stroke and consequent neurological deficits. The most important steps of atherosclerotic plaque development, leading to carotid stenosis, are well-known; however, their exact timeline and intricate causal relationships need to be more characterized. Methods: in a cohort of 119 patients, who underwent carotid endarterectomy, we studied the histological correlations between arterial calcification patterns and localization, the presence of the inflammatory infiltrate and osteopontin expression, with ulceration, thrombosis, and intra-plaque hemorrhage, as direct signs of vulnerability. Results: in patients with an inflammatory infiltrate, aphasia was more prevalent, and microcalcification, superficial calcification, and high-grade osteopontin expression were characteristic. Higher osteopontin expression was also correlated with the presence of a lipid core. Inflammation and microcalcification were significantly associated with plaque ulceration in logistic regression models; furthermore, ulceration and the inflammatory infiltrate were significant determinants of atherothrombosis. Conclusion: our results bring histological evidence for the critically important role of microcalcification and inflammatory cell invasion in the formation and destabilization of advanced carotid plaques. In addition, as a calcification organizer, high-grade osteopontin expression is associated with ulceration, the presence of a large lipid core, and may also have an intrinsic role in plaque progression.

18F-Sodium Fluoride PET/CT in Assessing Valvular Heart and Atherosclerotic Diseases

Aortic valve stenosis is the most common valvular disease in Western countries, while atherosclerotic cardiovascular disease is the foremost cause of death and disability worldwide. Valve degeneration and atherosclerosis are mediated by inflammation and calcification and inevitably progress over time. Computed tomography can visualise the later stages of macroscopic calcification but fails to assess the early stages of microcalcification and cannot differentiate active from burnt out disease states. Molecular imaging has the ability to provide complementary information related to disease activity, which may allow us to detect disease early, to predict disease progression and to monitor preventive or therapeutic strategies for in both aortic stenosis and atherosclerosis. PET/CT is a non-invasive imaging technique that enables visualization of ongoing molecular processes within small structures, such as the coronary arteries or heart valves. ¹⁸F-sodium fluoride (¹⁸F-NaF) binds hydroxyapatite deposits in the extracellular matrix, with preferential binding to newly developing deposits of microcalcification, which provides an assessment of calcification activity. In recent years, ¹⁸F-NaF has attracted the attention of many research groups and has been evaluated in several pathological cardiovascular processes. Histologic validation of the ¹⁸F-NaF PET signal in valvular disease and atherosclerosis has been reported in multiple independent studies. The selective high-affinity binding of ¹⁸F-NaF to microscopic calcified deposits (beyond the resolution of μCT) has been demonstrated ex vivo, as well as its ability to distinguish between areas of macro- and active microcalcification. In addition, prospective clinical studies have shown that baseline ¹⁸F-NaF uptake in patients with aortic stenosis and mitral annular calcification is correlated with subsequent calcium deposition and valvular dysfunction after a follow-up period of 2 years. In patients with surgical bioprosthetic aortic valves but without morphological criteria for prosthetic degeneration, increased ¹⁸F-NaF uptake at baseline was associated with subsequent bioprosthetic degeneration over time. Similar data were obtained in a cohort of patients with transcatheter aortic valve implantation. Furthermore, several studies have confirmed the association of coronary ¹⁸F-NaF uptake with adverse atherosclerotic plaque features, active disease and future disease progression. ¹⁸F-NaF uptake is also associated with future fatal or nonfatal myocardial infarction in patients with established coronary artery disease. The link between ¹⁸F-NaF uptake and active atherosclerotic disease has not only been demonstrated in the coronary arteries, but also in peripheral arterial disease, abdominal aortic aneurysms and carotid atherosclerosis. It can be assumed that ¹⁸F-NaF PET/CT will strengthen the diagnostic toolbox of practitioners in the coming years. Indeed, there is a strong medical need to diagnose degenerative valvular disease and to detect active atherosclerotic disease states. Finally, the use of ¹⁸F-NaF as a biomarker to monitor the efficacy of drug therapies in preventing these pathological processes is attractive. In this review, we consider the role of ¹⁸F-NaF PET/CT imaging in cardiac valvular diseases and atherosclerosis.

Mechanical injury accentuates lipid deposition in ApoE-/- mice and advance aortic valve stenosis: A novel modified aortic valve stenosis model

Background

Current mouse models still have limitations in studying aortic valve stenosis (AVS). A suitable animal model bearing a close resemblance to the pathophysiological processes of humans needs to be developed. Here, we combined two risk factors to create a mouse model that mimics the pathological features of human AVS.

Methods and results

We combined WI and hyperlipidemia in ApoE^-/- mice to explore the synergistic effect on the stenosis of the aortic valve. Transthoracic echocardiography revealed progressively increased peak velocity with age in ApoE^-/- mice to velocities above C57 mice when fed a high-fat diet after wire injury. Moreover, ApoE^-/- mice demonstrated lower cusp separation and lower aortic valve area after 8 weeks vs. C57 mice. Gross morphology and MRI showed advanced thickening, sclerosis aortic valve, narrowing of the orifice area, and micro-CT showed obvious calcification in the aortic valves in the hyperlipidemia group after wire injury. Histopathology studies showed thickening and fibrosis of aortic valve leaflets in the hyperlipidemia group after wire injury. Notably, lipid deposition was observed in ApoE^-/- mice 8 weeks after wire injury, accompanied by overexpressed apoB and apoA proteins. After wire injury, the hyperlipidemia group exhibited augmented inflammation, ROS production, and apoptosis in the leaflets. Moreover, the combination group exhibited advanced fibro-calcific aortic valves after wire injury.

Conclusion

Overall, we present the synergistic effect of wire injury and hyperlipidemia on lipoproteins deposition in the development of AVS in ApoE^-/- mice, this model bear close resemblance to human AVS pathology.

A fluorescent nano vector for early diagnosis and enhanced Interleukin-33 therapy of thoracic aortic dissection

Thoracic aortic dissection (TAD) is the most devastating complication of vascular disease. The accuracy of the clinical diagnosis and treatment of TAD at the early stage is still limited. Herein, we report a nano-delivery strategy for early diagnosis and the first case of interleukin-33 (IL-33) based therapy for the effective intervention of TAD. A targeted fluorescent nano vector (FNV) is designed to co-assemble with IL-33, which protects IL-33 and prolongs its half-life. With specific targeting ability to the thoracic aorta, FNV can diagnose TAD at its early stage through fluorescent imaging. FNV@IL-33 nanocomplex presents better therapeutic effects on mice TAD progression compared with that of IL-33 alone by reducing smooth muscle apoptosis. Administration of FNV@IL-33 two weeks before onset, the development of TAD is greatly intervened. Our study provides a novel approach for early diagnosis and effective IL-33 therapy of TAD, which opens attractive opportunities for clinical prevention of cardiovascular diseases.

Abnormally elevated EZH2-mediated H3K27me3 enhances osteogenesis in aortic valve interstitial cells by inhibiting SOCS3 expression

BACKGROUND AND AIMS

The osteogenic transition of aortic valve interstitial cells (AVICs) plays a critical role for the progression of calcific aortic valve disease (CAVD). Enhancer of zeste homolog 2 (EZH2) is an important methyltransferase for histone H3 Lys27 (H3K27) that has been found to be involved in osteogenesis. Here, we investigated the effect and mechanism of EZH2 in CAVD progression.

METHODS

High throughout mRNA sequencing, qRT-PCR and immunoblot were performed to screen differentially expressed genes in non-CAVD and CAVD aortic valves. To investigate the role of EZH2 and SOCS3 in osteogenesis, AVICs were treated with siRNA, adenovirus and specific inhibitors, then osteogenic markers and mineralized deposits were examined. In vivo, the morphology and function of aortic valves were investigated by HE stain and echocardiography in ApoE^-/- mice fed a long-term western diet (WD).

RESULTS

We discovered that EZH2 was upregulated and SOCS3 was downregulated in calcified aortic valves. In AVICs, inhibition or silencing of EZH2 attenuated the osteogenic responses. On the other hand, demethylases inhibitor (GSK-J4) enhanced osteogenic transition of AVICs. Moreover, SOCS3 knockdown enhanced the expression of osteogenic markers, while SOCS3 overexpression suppressed osteogenesis and calcification. The chromatin immunoprecipitation and restored experiments indicated that EZH2 directly targeted SOCS3 to promote osteogenic responses of AVICs. In vivo, treatment with EZH2 inhibitor through intraperitoneal injection attenuated aortic valve thickening, calcification and dysfunction induced by WD.

CONCLUSIONS

Collectively, we found that EZH2-mediated H3K27me3 enhanced osteogenesis and microcalcification of AVICs via inhibiting SOCS3 expression, which provides potential targets for future therapeutic interventions of CAVD.

Interleukin-29 Accelerates Vascular Calcification via JAK2/STAT3/BMP2 Signaling

Background Vascular calcification (VC), associated with enhanced cardiovascular morbidity and mortality, is characterized by the osteogenic transdifferentiation of vascular smooth muscle cells. Inflammation promotes VC initiation and progression. Interleukin (IL)-29, a newly discovered member of type III interferon, has recently been implicated in the pathogenesis of autoimmune diseases. Here we evaluated the role of IL-29 in the VC process and underlying inflammatory mechanisms. Methods and Results The mRNA expression of IL-29 was significantly increased and positively associated with an increase in BMP2 (bone morphogenetic protein 2) mRNA level in calcified carotid arteries from patients with coronary artery disease or chronic kidney disease. IL-29 and BMP2 proteins are colocalized in human calcified arteries. IL-29 binding to its specific receptor IL-28Rα (IL-28 receptor α) (IL-29/IL-28Rα) inhibited the proliferation of rat vascular smooth muscle cells without altering cell apoptosis or migration. IL-29 promoted the calcification of rat vascular smooth muscle cells and their osteogenic transdifferentiation in vitro as well as the rat aortic ring calcification ex vivo, induced by the calcification medium or osteogenic medium. The procalcification effect of IL-29 was reduced by pharmacological inhibition of IL-29/IL-28Rα binding as well as suppression of janus kinase 2/signal transducer and activator of transcription pathway activation, accompanied by decreased BMP2 expression in the cultured rat vascular smooth muscle cells. Conclusions These results suggest an important role of IL-29 in VC development, at least partly, via activating the janus kinase 2/signal transducer and activator of transcription 3 signaling. Inhibition of IL-29 or its specific receptor, IL-28Rα, may provide a novel strategy to reduce VC in patients with vascular diseases.

Development and analysis of a comprehensive diagnostic model for aortic valve calcification using machine learning methods and artificial neural networks

BACKGROUND

Although advanced surgical and interventional treatments are available for advanced aortic valve calcification (AVC) with severe clinical symptoms, early diagnosis, and intervention is critical in order to reduce calcification progression and improve patient prognosis. The aim of this study was to develop therapeutic targets for improving outcomes for patients with AVC.

MATERIALS AND METHODS

We used the public expression profiles of individuals with AVC (GSE12644 and GSE51472) to identify potential diagnostic markers. First, the R software was used to identify differentially expressed genes (DEGs) and perform functional enrichment analysis. Next, we combined bioinformatics techniques with machine learning methodologies such as random forest algorithms and support vector machines to screen for and identify diagnostic markers of AVC. Subsequently, artificial neural networks were employed to filter and model the diagnostic characteristics for AVC incidence. The diagnostic values were determined using the receiver operating characteristic (ROC) curves. Furthermore, CIBERSORT immune infiltration analysis was used to determine the expression of different immune cells in the AVC. Finally, the CMap database was used to predict candidate small compounds as prospective AVC therapeutics.

RESULTS

A total of 78 strong DEGs were identified. The leukocyte migration and pid integrin 1 pathways were highly enriched for AVC-specific DEGs. CXCL16, GPM6A, BEX2, S100A9, and SCARA5 genes were all regarded diagnostic markers for AVC. The model was effectively constructed using a molecular diagnostic score system with significant diagnostic value (AUC = 0.987) and verified using the independent dataset GSE83453 (AUC = 0.986). Immune cell infiltration research revealed that B cell naive, B cell memory, plasma cells, NK cell activated, monocytes, and macrophage M0 may be involved in the development of AVC. Additionally, all diagnostic characteristics may have varying degrees of correlation with immune cells. The most promising small molecule medicines for reversing AVC gene expression are Doxazosin and Terfenadine.

CONCLUSION

It was identified that CXCL16, GPM6A, BEX2, S100A9, and SCARA5 are potentially beneficial for diagnosing and treating AVC. A diagnostic model was constructed based on a molecular prognostic score system using machine learning. The aforementioned immune cell infiltration may have a significant influence on the development and incidence of AVC.

CD137-CD137L Aggravates Calcification of Vascular Smooth Muscle Cell and Vasculature of ApoE-/- Mice Via Rab7-Mediated Autophagy

Vascular calcification is an independent risk factor for acute cardiovascular events and a predictor of adverse prognosis; the abnormal fusion and degradation of autophagosomes and lysosomes are closely related to the calcification of VSMC and aortic AS plaque in ApoE-/- mice. Rab7 is a member of the Ras protein family and acts as a molecular switch in the fusion between autophagosomes and lysosomes. In this study, we found that the activation of the CD137-CD137L signal promoted calcification by inhibiting the expression and activity of Rab7, which regulates the degradation of autophagic cargo in vascular smooth muscle cells (VSMCs) and aortic atherosclerosis (AS) plaques in ApoE-/- mice. Knockdown of Rab7 impaired its tethering with the downstream molecule FYVE and coiled-coil containing 1 (FYCO1), which transports autophagosomes to lysosomes through microtubule motor kinesins and fuses with lysosomes to degrade the autophagic content. Overexpression of Rab7-alleviated calcification caused by the activation of the CD137 signaling pathway. In addition, FYCO1 knockdown promoted calcification even though the expression and activity of Rab7 were normal. Our results suggest that Rab7 is the target of CD137 signaling; Rab7 cannot interact with its downstream molecule FYCO1 when its activity and expression were inhibited by the activation of CD137 signaling pathway, thus inhibiting the autophagic degradation and promoting calcification.

Aortic valve sclerosis and subclinical LV dysfunction in the general population with normal LV geometry

AIMS

Aortic valve sclerosis (AVS) without hemodynamically significant obstruction is related to cardiovascular morbidity and mortality independent of left ventricular (LV) hypertrophy, although the underlying mechanisms remain unknown. This study investigated the prevalence of AVS and its association with subclinical LV systolic and diastolic dysfunction in individuals with normal LV geometry free of cardiovascular disease.

METHODS

We examined 962 participants with normal LV geometry and free from significant AV stenosis who underwent standard and speckle-tracking echocardiography. AVS was categorized into 4 groups as follows: no AVS, AV thickening, calcification on one leaflet and calcification on ≥2 leaflets.

RESULTS

Among the 962 participants, 767 (79.7%) individuals were classified as no AVS, 74 (7.7%) as AV thickening, 87 (9.0%) as calcification on one leaflet, and 34 (3.5%) as calcification on ≥2 leaflets. The prevalence of subclinical LV diastolic dysfunction (E/e' ratio ≥13) and systolic dysfunction (LV global longitudinal strain (GLS) > -17.0% for men and > -18.0% for women) were greater in AVS groups than those in no AVS group. Subclinical LV diastolic impairment was evident from AV thickening and systolic dysfunction was observed at AV calcification. Multivariable logistic regression analysis demonstrated that AV thickening as well as calcification were independently associated with subclinical LV diastolic impairment (all p < 0.05), while only AV calcification on ≥2 leaflets conferred significant increased risk of impaired LVGLS.

CONCLUSIONS

AVS was observed in approximately 20% individuals without cardiac disease and was associated with subclinical LV diastolic and systolic function even in the absence of LV morphological change.

NLRP3 inflammasome: The rising star in cardiovascular diseases

Cardiovascular diseases (CVDs) are the prevalent cause of mortality around the world. Activation of inflammasome contributes to the pathological progression of cardiovascular diseases, including atherosclerosis, abdominal aortic aneurysm, myocardial infarction, dilated cardiomyopathy, diabetic cardiomyopathy, heart failure, and calcific aortic valve disease. The nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome plays a critical role in the innate immune response, requiring priming and activation signals to provoke the inflammation. Evidence shows that NLRP3 inflammasome not only boosts the cleavage and release of IL-1 family cytokines, but also leads to a distinct cell programmed death: pyroptosis. The significance of NLRP3 inflammasome in the CVDs-related inflammation has been extensively explored. In this review, we summarized current understandings of the function of NLRP3 inflammasome in CVDs and discussed possible therapeutic options targeting the NLRP3 inflammasome.

Antiphospholipid antibodies in patients with calcific aortic valve stenosis

OBJECTIVES

The antiphospholipid syndrome is defined by antiphospholipid antibodies (aPL) together with arterial and/or venous thromboembolism and/or obstetric morbidities. aPL are overrepresented in SLE and acute myocardial infarction, but it is unknown whether aPL are associated with calcific aortic valve stenosis (CAVS) in the general population. The prevalence of aPL and other SLE-associated autoantibodies and their impact on aortic valve transcriptomics were therefore determined.

METHODS

A total of 233 tricuspid CAVS cases (median age 74, 69% male) and an age- and sex-matched control population were included. aPL were measured as anti-cardiolipin and anti-β2Glycoprotein-I of IgG/M/A isotypes. Resilient, thickened and calcified aortic valve (AV) tissue derived from five aPL positive and five matched aPL negative CAVS patients undergoing surgical aortic valve replacement were analysed by microarrays.

RESULTS

The prevalence of positivity for any aPL (IgG/M/A) in patients with CAVS was 6.4% (95% CI 3.6% - 10.4%: n = 233). aPL IgG was significantly more prevalent in CAVS cases vs controls (4.6% vs 0.6%, P = 0.04). AV tissue from aPL IgG/IgM-positive patients was negatively enriched in pathways related to interferon signalling. One hundred differentially expressed genes could predict local AV CAVS progression with supervised machine learning algorithms.

CONCLUSIONS

aPL IgG was more common in CAVS patients compared with matched controls and aPL positivity was associated with altered AV transcriptomics related to local disease progression and interferon pathways. Further studies should aim to establish aPL as a possible risk marker and/or causal factor for CAVS and could offer new precision therapeutic targets.

Left-Sided Degenerative Valvular Heart Disease in Type 1 and Type 2 Diabetes

BACKGROUND

The role of diabetes in the development of valvular heart disease, and, in particular, the relation with risk factor control, has not been extensively studied.

METHODS

We included 715 143 patients with diabetes registered in the Swedish National Diabetes Register and compared them with 2 732 333 matched controls randomly selected from the general population. First, trends were analyzed with incidence rates and Cox regression, which was also used to assess diabetes as a risk factor compared with controls, and, second, separately in patients with diabetes according to the presence of 5 risk factors.

RESULTS

The incidence of valvular outcomes is increasing among patients with diabetes and the general population. In type 2 diabetes, systolic blood pressure, body mass index, and renal function were associated with valvular lesions. Hazard ratios for patients with type 2 diabetes who had nearly all risk factors within target ranges, compared with controls, were as follows: aortic stenosis 1.34 (95% CI, 1.31-1.38), aortic regurgitation 0.67 (95% CI, 0.64-0.70), mitral stenosis 1.95 (95% CI, 1.76-2.20), and mitral regurgitation 0.82 (95% CI, 0.79-0.85). Hazard ratios for patients with type 1 diabetes and nearly optimal risk factor control were as follows: aortic stenosis 2.01 (95% CI, 1.58-2.56), aortic regurgitation 0.63 (95% CI, 0.43-0.94), and mitral stenosis 3.47 (95% CI, 1.37-8.84). Excess risk in patients with type 2 diabetes for stenotic lesions showed hazard ratios for aortic stenosis 1.62 (95% CI, 1.59-1.65), mitral stenosis 2.28 (95% CI, 2.08-2.50), and excess risk in patients with type 1 diabetes showed hazard ratios of 2.59 (95% CI, 2.21-3.05) and 11.43 (95% CI, 6.18-21.15), respectively. Risk for aortic and mitral regurgitation was lower in type 2 diabetes: 0.81 (95% CI, 0.78-0.84) and 0.95 (95% CI, 0.92-0.98), respectively.

CONCLUSIONS

Individuals with type 1 and 2 diabetes have greater risk for stenotic lesions, whereas risk for valvular regurgitation was lower in patients with type 2 diabetes. Patients with well-controlled cardiovascular risk factors continued to display higher risk for valvular stenosis, without a clear stepwise decrease in risk between various degrees of risk factor control.

Is cell regeneration and infiltration a double edged sword for porcine aortic valve deterioration? A large cohort of histopathological analysis

BACKGROUND AND OBJECTIVE

Bioprostheses are the most common prostheses used for valve replacement in the Western medicine. The major flaw of bioprostheses is the occurrence of structural valve deterioration (SVD). This study aimed to assess the pathological features of porcine aortic valve (PAV)-SVD based on histomorphological and immunopathological characteristics of a large cohort of patients.

METHODS

Histopathological data of 109 cases with resected PAV were collected. The type and amount of infiltrated cells were evaluated in the different types of bioprosthetic SVD by immunohistochemical staining.

RESULTS

The most common cause of SVD was calcification, leaflet tear, and dehiscence (23.9%, 19.3%, and 18.3%, respectively). Immunohistochemical staining demonstrated that macrophages were infiltrated in the calcified, lacerated and dehiscence PAV, in which both M1 and M2 macrophages were existed in the calcified PAV. Importantly, the higher content of M1 macrophages and less content of M2 macrophages were found in the lacerated and dehiscence PAV, and MMP-1 expression was mainly found in the lacerated PAV. The endothelialization rate of leaflet dehiscence was higher than that of calcified and lacerated leaflets. A large number of CD31+/CD11b+ cells was aggregated in the spongy layer in the lacerated and dehiscence PAV.

CONCLUSION

Cell regeneration and infiltration is a double edged sword for the PAV deterioration. Macrophage infiltration is involved in the different types of SVD, while only MMP-1 expression is involved in lacerated leaflets. The macrophage subtype of circulating angiogenic cells in dehiscence and tear PAV could be identified, which could reserve macrophages in the PAV-SVD.

PTP1B Inhibition Improves Mitochondrial Dynamics to Alleviate Calcific Aortic Valve Disease Via Regulating OPA1 Homeostasis

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Increased PTP1B was observed in the human calcified aortic valve leaflets and VIC osteogenesis, which indicated a novel association of PTP1B with aortic valve calcification.

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MSI-1436, a specific pharmacological PTP1B inhibitor, attenuated osteogenic and myofibrogenic differentiation of VICs, which coincided with preventing aortic valve fibrocalcific disease in a diet-induced mouse model of CAVD.

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Treatment of CAVD with PTP1B inhibitor mitigated the disorder of aortic jet velocity and mean gradient in vivo.

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PTP1B inhibition preserved the mitochondrial biogenesis and function in VIC osteogenesis via regulating OPA1 homeostasis.

There are currently no pharmacological therapies for calcific aortic valve disease (CAVD). Here, we evaluated the role of protein tyrosine phosphatase 1B (PTP1B) inhibition in CAVD. Up-regulation of PTP1B was critically involved in calcified human aortic valve, and PTP1B inhibition had beneficial effects in preventing fibrocalcific response in valvular interstitial cells and LDLR^−/− mice. In addition, we reported a novel function of PTP1B in regulating mitochondrial homeostasis by interacting with the OPA1 isoform transition in valvular interstitial cell osteogenesis. Thus, these findings have identified PTP1B as a potential target for preventing aortic valve calcification in patients with CAVD.

Sex-Differences in Aortic Stenosis: Mechanistic Insights and Clinical Implications

Objective

We aim to analyse sex-specific differences in aortic valves (AVs) and valve interstitial cells (VICs) from aortic stenosis (AS) patients.

Approach and Results

238 patients with severe AS undergoing surgical valve replacement were recruited. Two hundred and two AVs (39.1% women) were used for ex vivo analyses and 36 AVs (33.3% women) for in vitro experiments. AVs from men presented increased levels of the inflammatory molecules interleukin (IL)-1β, IL-6, Rantes, and CD45. Oxidative stress (eNOS, myeloperoxidase, malondialdehyde and nitrotyrosine) was upregulated in male AVs. Concerning fibrosis, similar levels of collagen type I, decreased levels of collagen type III and enhanced fibronectin, active Lox-1 and syndecan-1 expressions were found in AVs from men compared with women. Extracellular matrix (ECM) remodeling was characterized by reduced metalloproteinase-1 and 9 expression and increased tissue inhibitor of metalloproteinase-2 expression in male AVs. Importantly, osteogenic markers (bone morphogenetic protein-9, Rank-L, osteopontin, periostin, osteocalcin and Sox-9) and apoptosis (Bax, Caspase 3, p53, and PARP1) were enhanced in AVs from men as compared to women. Isolated male VICs presented higher myofibroblast-like phenotype than female VICs. Male VICs exhibited increased inflammatory, oxidative stress, fibrotic, apoptosis and osteogenic differentiation markers.

Conclusions

Our results suggest that the mechanisms driving the pathogenesis of AS could be different in men and women. Male AVs and isolated VICs presented more inflammation, oxidative stress, ECM remodeling and calcification as compared to those from women. A better knowledge of the pathophysiological pathways in AVs and VICs will allow the development of sex-specific options for the treatment of AS.

Osteomodulin attenuates smooth muscle cell osteogenic transition in vascular calcification

Rationale

Vascular calcification is a prominent feature of late‐stage diabetes, renal and cardiovascular disease (CVD), and has been linked to adverse events. Recent studies in patients reported that plasma levels of osteomodulin (OMD), a proteoglycan involved in bone mineralisation, associate with diabetes and CVD. We hypothesised that OMD could be implicated in these diseases via vascular calcification as a common underlying factor and aimed to investigate its role in this context.

Methods and results

In patients with chronic kidney disease, plasma OMD levels correlated with markers of inflammation and bone turnover, with the protein present in calcified arterial media. Plasma OMD also associated with cardiac calcification and the protein was detected in calcified valve leaflets by immunohistochemistry. In patients with carotid atherosclerosis, circulating OMD was increased in association with plaque calcification as assessed by computed tomography. Transcriptomic and proteomic data showed that OMD was upregulated in atherosclerotic compared to control arteries, particularly in calcified plaques, where OMD expression correlated positively with markers of smooth muscle cells (SMCs), osteoblasts and glycoproteins. Immunostaining confirmed that OMD was abundantly present in calcified plaques, localised to extracellular matrix and regions rich in α‐SMA⁺ cells. In vivo, OMD was enriched in SMCs around calcified nodules in aortic media of nephrectomised rats and in plaques from ApoE^−/− mice on warfarin. In vitro experiments revealed that OMD mRNA was upregulated in SMCs stimulated with IFNγ, BMP2, TGFβ1, phosphate and β‐glycerophosphate, and by administration of recombinant human OMD protein (rhOMD). Mechanistically, addition of rhOMD repressed the calcification process of SMCs treated with phosphate by maintaining their contractile phenotype along with enriched matrix organisation, thereby attenuating SMC osteoblastic transformation. Mechanistically, the role of OMD is exerted likely through its link with SMAD3 and TGFB1 signalling, and interplay with BMP2 in vascular tissues.

Conclusion

We report a consistent association of both circulating and tissue OMD levels with cardiovascular calcification, highlighting the potential of OMD as a clinical biomarker. OMD was localised in medial and intimal α‐SMA⁺ regions of calcified cardiovascular tissues, induced by pro‐inflammatory and pro‐osteogenic stimuli, while the presence of OMD in extracellular environment attenuated SMC calcification.

Role of Extracellular Vesicles in the Pathogenesis of Vascular Damage

Extracellular vesicles (EVs) are nanosized membrane-bound structures released by cells that are able to transfer nucleic acids, protein cargos, and metabolites to specific recipient cells, allowing cell-to-cell communications in an endocrine and paracrine manner. Endothelial, leukocyte, and platelet-derived EVs have emerged both as biomarkers and key effectors in the development and progression of different stages of vascular damage, from earliest alteration of endothelial function, to advanced atherosclerotic lesions and cardiovascular calcification. Under pathological conditions, circulating EVs promote endothelial dysfunction by impairing vasorelaxation and instigate vascular inflammation by increasing levels of adhesion molecules, reactive oxygen species, and proinflammatory cytokines. Platelets, endothelial cells, macrophages, and foam cells secrete EVs that regulate macrophage polarization and contribute to atherosclerotic plaque progression. Finally, under pathological stimuli, smooth muscle cells and macrophages secrete EVs that aggregate between collagen fibers and serve as nucleation sites for ectopic mineralization in the vessel wall, leading to formation of micro- and macrocalcification. In this review, we summarize the emerging evidence of the pathological role of EVs in vascular damage, highlighting the major findings from the most recent studies and discussing future perspectives in this research field.

10-Year All-Cause Mortality Following Percutaneous or Surgical Revascularization in Patients With Heavy Calcification

OBJECTIVES

The aim of this study was to assess 10-year all-cause mortality in patients with heavily calcified lesions (HCLs) undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

BACKGROUND

Limited data are available on very long term outcomes in patients with HCLs according to the mode of revascularization.

METHODS

This substudy of the SYNTAXES (Synergy Between PCI With Taxus and Cardiac Surgery Extended Survival) study assessed 10-year all-cause mortality according to the presence of HCLs within lesions with >50% diameter stenosis and identified during the calculation of the anatomical SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score among 1,800 patients with the 3-vessel disease and/or left main disease randomized to PCI or CABG in the SYNTAX trial. Patients with HCLs were further stratified according to disease type (3-vessel disease or left main disease) and assigned treatment (PCI or CABG).

RESULTS

The 532 patients with ≥1 HCL had a higher crude mortality rate at 10 years than those without (36.4% vs 22.3%; HR: 1.79; 95% CI: 1.49-2.16; P < 0.001). After adjustment, an HCL remained an independent predictor of 10-year mortality (HR: 1.36; 95% CI: 1.09-1.69; P = 0.006). There was a significant interaction in mortality between treatment effect (PCI and CABG) and the presence or absence of HCLs (P_interaction = 0.005). In patients without HCLs, mortality was significantly higher after PCI than after CABG (26.0% vs 18.8%; HR: 1.44; 95% CI: 0.97-1.41; P = 0.003), whereas in those with HCLs, there was no significant difference (34.0% vs 39.0%; HR: 0.85; 95% CI: 0.64-1.13; P = 0.264).

CONCLUSIONS

At 10 years, the presence of an HCL was an independent predictor of mortality, with a similar prognosis following PCI or CABG. Whether HCLs require special consideration when deciding the mode of revascularization beyond their current contribution to the anatomical SYNTAX score deserves further evaluation. (Synergy Between PCI With TAXUS and Cardiac Surgery: SYNTAX Extended Survival [SYNTAXES], NCT03417050; SYNTAX Study: TAXUS Drug-Eluting Stent Versus Coronary Artery Bypass Surgery for the Treatment of Narrowed Arteries [SYNTAX], NCT00114972).

Proinflammatory Matrix Metalloproteinase-1 Associates With Mitral Valve Leaflet Disruption Following Percutaneous Mitral Valvuloplasty

Mitral regurgitation (MR) is a major complication of the percutaneous mitral valvuloplasty (PMV). Despite high technical expertise and cumulative experience with the procedure, the incidence rate of severe MR has not decreased. Although some of MR can be anticipated by echocardiographic analysis; leaflet tearing, which leads to the most dreaded type of MR, remains unpredictable. Irregular valvular collagen remodeling is likely to compromise tissue architecture and increase the tearing risk during PMV balloon inflation. In this study, we evaluated histological and molecular characteristics of excised mitral valves from patients with rheumatic mitral stenosis (MS) who underwent emergency surgery after PMV due to severe MR caused by leaflet tear. Those findings were compared with patients who underwent elective mitral valve replacement surgery owing to severe MS, in whom PMV was not indicated. In vitro assay using peripheral blood mononuclear cells was performed to better understand the impact of the cellular and molecular alterations identified in leaflet tear mitral valve specimens. Our analysis showed that focal infiltration of inflammatory cells contributes to accumulation of MMP-1 and IFN-γ in valve leaflets. Moreover, we showed that IFN-γ increase the expression of MMP-1 in CD14⁺ cells (monocytes) in vitro. Thus, inflammatory cells contribute to unevenly remodel collagen resulting in variable thickening causing abnormalities in leaflet architecture making them more susceptible to laceration.

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.

Calcific aortic valve disease: from molecular and cellular mechanisms to medical therapy

Calcific aortic valve disease (CAVD) is a highly prevalent condition that comprises a disease continuum, ranging from microscopic changes to profound fibro-calcific leaflet remodelling, culminating in aortic stenosis, heart failure, and ultimately premature death. Traditional risk factors, such as hypercholesterolaemia and (systolic) hypertension, are shared among atherosclerotic cardiovascular disease and CAVD, yet the molecular and cellular mechanisms differ markedly. Statin-induced low-density lipoprotein cholesterol lowering, a remedy highly effective for secondary prevention of atherosclerotic cardiovascular disease, consistently failed to impact CAVD progression or to improve patient outcomes. However, recently completed phase II trials provide hope that pharmaceutical tactics directed at other targets implicated in CAVD pathogenesis offer an avenue to alter the course of the disease non-invasively. Herein, we delineate key players of CAVD pathobiology, outline mechanisms that entail compromised endothelial barrier function, and promote lipid homing, immune-cell infiltration, and deranged phospho-calcium metabolism that collectively perpetuate a pro-inflammatory/pro-osteogenic milieu in which valvular interstitial cells increasingly adopt myofibro-/osteoblast-like properties, thereby fostering fibro-calcific leaflet remodelling and eventually resulting in left ventricular outflow obstruction. We provide a glimpse into the most promising targets on the horizon, including lipoprotein(a), mineral-binding matrix Gla protein, soluble guanylate cyclase, dipeptidyl peptidase-4 as well as candidates involved in regulating phospho-calcium metabolism and valvular angiotensin II synthesis and ultimately discuss their potential for a future therapy of this insidious disease.

IL-1β in atherosclerotic vascular calcification: From bench to bedside

Atherosclerotic vascular calcification contributes to increased risk of death in patients with cardiovascular diseases. Assessing the type and severity of inflammation is crucial in the treatment of numerous cardiovascular conditions. IL-1β, a potent proinflammatory cytokine, plays diverse roles in the pathogenesis of atherosclerotic vascular calcification. Several large-scale, population cohort trials have shown that the incidence of cardiovascular events is clinically reduced by the administration of anti-IL-1β therapy. Anti-IL-1β therapy might reduce the incidence of cardiovascular events by affecting atherosclerotic vascular calcification, but the mechanism underlying this effect remains unclear. In this review, we summarize current knowledge on the role of IL-1β in atherosclerotic vascular calcification, and describe the latest results reported in clinical trials evaluating anti-IL-1β therapies for the treatment of cardiovascular diseases. This review will aid in improving current understanding of the pathophysiological roles of IL-1β and mechanisms underlying its activity.

Interferons Are Pro-Inflammatory Cytokines in Sheared-Stressed Human Aortic Valve Endothelial Cells

Calcific aortic valve disease (CAVD) is an athero-inflammatory process. Growing evidence supports the inflammation-driven calcification model, mediated by cytokines such as interferons (IFNs) and tumor necrosis factor (TNF)-α. Our goal was investigating IFNs' effects in human aortic valve endothelial cells (VEC) and the potential differences between aortic (aVEC) and ventricular (vVEC) side cells. The endothelial phenotype was analyzed by Western blot, qPCR, ELISA, monocyte adhesion, and migration assays. In mixed VEC populations, IFNs promoted the activation of signal transducers and activators of transcription-1 and nuclear factor-κB, and the subsequent up-regulation of pro-inflammatory molecules. Side-specific VEC were activated with IFN-γ and TNF-α in an orbital shaker flow system. TNF-α, but not IFN-γ, induced hypoxia-inducible factor (HIF)-1α stabilization or endothelial nitric oxide synthase downregulation. Additionally, IFN-γ inhibited TNF-α-induced migration of aVEC. Also, IFN-γ triggered cytokine secretion and adhesion molecule expression in aVEC and vVEC. Finally, aVEC were more prone to cytokine-mediated monocyte adhesion under multiaxial flow conditions as compared with uniaxial flow. In conclusion, IFNs promote inflammation and reduce TNF-α-mediated migration in human VEC. Moreover, monocyte adhesion was higher in inflamed aVEC sheared under multiaxial flow, which may be relevant to understanding the initial stages of CAVD.

Aortic valve disease in diabetes: Molecular mechanisms and novel therapies

Valve disease and particularly calcific aortic valve disease (CAVD) and diabetes (DM) are progressive diseases constituting a global health burden for all aging societies (Progress in Cardiovascular Diseases. 2014;56(6):565: Circulation Research. 2021;128(9):1344). Compared to non‐diabetic individuals (The Lancet. 2008;371(9626):1800: The American Journal of Cardiology. 1983;51(3):403: Journal of the American College of Cardiology. 2017;69(12):1523), the diabetic patients have a significantly greater propensity for cardiovascular disorders and faster degeneration of implanted bioprosthetic aortic valves. Previously, using an original experimental model, the diabetic‐hyperlipemic hamsters, we have shown that the earliest alterations induced by these conditions occur at the level of the aortic valves and, with time these changes lead to calcifications and CAVD. However, there are no pharmacological treatments available to reverse or retard the progression of aortic valve disease in diabetes, despite the significant advances in the field. Therefore, it is critical to uncover the mechanisms of valve disease progression, find biomarkers for diagnosis and new targets for therapies. This review aims at presenting an update on the basic research in CAVD in the context of diabetes. We provide an insight into the accumulated data including our results on diabetes‐induced progressive cell and molecular alterations in the aortic valve, new potential biomarkers to assess the evolution and therapy of the disease, advancement in targeted nanotherapies, tissue engineering and the potential use of circulating endothelial progenitor cells in CAVD.

Bone mineral density and long-term progression of aortic valve and mitral annular calcification: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Bone and mineral metabolism has been implicated in the pathophysiology of cardiac valve calcification. Whether bone demineralization, a common aging-related disorder, promotes calcific valve disease remains uncertain. We tested the hypothesis that low bone mineral density (BMD) is associated with greater incidence/progression of cardiac valve calcification in the Multi-Ethnic Study of Atherosclerosis.

METHODS

Using linear mixed-effects models, we related baseline measurement of BMD of the thoracic vertebrae by computed tomography (CT) in 6768 participants to serial CT assessments of aortic valve calcification (AVC) and mitral annular calcification (MAC) obtained over a >10-year period.

RESULTS

After multivariable adjustment, lower BMD (per SD decrement) was associated with accelerated increase in AVC over time in women (0.76 [95% CI 0.42,1.09] Agatston -units [AU]/year) and men (1.41 [95% CI 0.48,2.33] AU/year), as well as for MAC in women (3.22 [95% CI 1.16,5.28] AU/year) and men (3.59 [95% CI 2.09,5.09] AU/year). Significant effect modification was observed, with more pronounced BMD-related acceleration of AVC and MAC progression in older or white participants of one or both sexes, as well as by estimated glomerular filtration rate, though the latter differed by sex for AVC and MAC.

CONCLUSIONS

In this multi-ethnic cohort, low thoracic BMD was significantly, but modestly, associated with increased AVC and MAC progression. This suggests that altered bone mineral metabolism does not have a major impact on calcific valve disease in the general population, but the possibility of a more meaningful influence in higher-risk individuals with osteoporosis will require further investigation.

Sitagliptin attenuates arterial calcification by downregulating oxidative stress-induced receptor for advanced glycation end products in LDLR knockout mice

Diabetes is a complex disease characterized by hyperglycemia, dyslipidemia, and insulin resistance. Plasma advanced glycation end products (AGEs) activated the receptor for advanced glycation end products (RAGE) and the activation of RAGE is implicated to be the pathogenesis of type 2 diabetic mellitus (T2DM) patient vascular complications. Sitagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, is a new oral hypoglycemic agent for the treatment of T2DM. However, the beneficial effects on vascular calcification remain unclear. In this study, we used a high-fat diet (HFD)-fed low-density lipoprotein receptor deficiency (LDLR^−/−) mice model to investigate the potential effects of sitagliptin on HFD-induced arterial calcification. Mice were randomly divided into 3 groups: (1) normal diet group, (2) HFD group and (3) HFD + sitagliptin group. After 24 weeks treatment, we collected the blood for chemistry parameters and DPP4 activity measurement, and harvested the aorta to evaluate calcification using immunohistochemistry and calcium content. To determine the effects of sitagliptin, tumor necrosis factor (TNF)-α combined with S100A12 was used to induce oxidative stress, activation of nicotinamide adenine dinucleotide phosphate (NADPH), up-regulation of bone markers and RAGE expression, and cell calcium deposition on human aortic smooth muscle cells (HASMCs). We found that sitagliptin effectively blunted the HFD-induced artery calcification and significantly lowered the levels of fasting serum glucose, triglyceride (TG), nitrotyrosine and TNF-α, decreased the calcium deposits, and reduced arterial calcification. In an in-vitro study, both S100A12 and TNF-α stimulated RAGE expression and cellular calcium deposits in HASMCs. The potency of S100A12 on HASMCs was amplified by the presence of TNF-α. Sitagliptin and Apocynin (APO), an NADPH oxidase inhibitor, inhibited the TNF-α + S100A12-induced NADPH oxidase and nuclear factor (NF)-κB activation, cellular oxidative stress, RAGE expression, osteo transcription factors expression and calcium deposition. In addition, treatment with sitagliptin, knockdown of RAGE or TNF-α receptor blunted the TNF-α + S100A12-induced RAGE expression. Our findings suggest that sitagliptin may suppress the initiation and progression of arterial calcification by inhibiting the activation of NADPH oxidase and NF-κB, followed by decreasing the expression of RAGE.