Toll-like-receptor-3 function is critical for aortic valve stenosis development in mice

Abstract Background Aortic valve stenosis (AS) is the most common valve diseases in the western world. After having been considered a passive degenerative process, which develops as an inevitable consequence of age-related valvular degeneration, basic research of the last two decades has led to a paradigm shift. It is now believed that AS pathophysiology is driven by distinct molecular and cellular mechanisms which include inflammatory pathways. In recent years, Toll-like-receptor-3 (TLR3) has emerged as a major regulator of vascular inflammation. TLR3 is a lysosomal pattern recognition receptor that recognizes single and double stranded RNA. Its activation leads to expression of pro-inflammatory cytokines via NFkb activation. The role of TLR3 in the development of AS has never been investigated. Methods Severe AS was induced in Wildtype-, ApoE- and TLR3/ApoE−/− mice. For this, a coronary springwire was used to induce an endothelial injury under echocardiographic guidance. Stenosis development was confirmed via ultrasound examinations. To inhibit TLR-3 activation, TLR3/RNA- Complex inhibitor C4a was injected every 48h after wire injury in WT mice. Valves were explanted and stained with hematoxylin/eosin (valve thickening) or anti-68 (macrophage infiltration). Valves from patients who received aortic valve replacement due to AS or aortic regurgitation (AR) were collected and mRNA levels of TLR3 and MyD88 were measured with use of quantitative-PCR. Results To evaluate weather TLR3 effects AS development in mice, we subjected TLR3/ApoE double- and ApoE knockout mice to our model of wire-induced AS. Surprisingly, TLR3 deficient mice failed to develop AS after wire injury. Peak velocity measurements showed no increase and histological analysis showed lower aortic valve area and macrophage infiltration compared to control mice. In order to pharmacological inhibit TLR3, WT mice were treated with C4a after wire injury. Compared to PBS control, C4a mice also did not develop AS upon wire injury. Trans-aortic valve peak velocity levels were significantly lower in C4a mice. Histological analysis underlined these results and showed thinner aortic valves and decreased macrophage infiltration in C4a mice comparted to control animals. To confirm our hypothesis, the expression of TLR3 and its downstream effector MyD88 were measured in human aortic valve specimens. qPCR analysis revealed decreased TLR3 and MyD88 expression in patients with AS compared to patients with AR. Conclusion In the presented study, we present first data that theTLR3 has a crucial role in the development of AS in mice. The exact downstream effects after TLR3 activation in AS need to be further investigated. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)

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TLR7 Expression Is Associated with M2 Macrophage Subset in Calcific Aortic Valve Stenosis

Cells ◽

10.3390/cells9071710 ◽

2020 ◽

Vol 9 (7) ◽

pp. 1710 ◽

Cited By ~ 1

Author(s):

Glykeria Karadimou ◽

Oscar Plunde ◽

Sven-Christian Pawelzik ◽

Miguel Carracedo ◽

Per Eriksson ◽

...

Keyword(s):

Aortic Valve ◽

Aortic Valve Stenosis ◽

Ex Vivo ◽

M2 Macrophage ◽

Mrna Levels ◽

Aortic Valves ◽

Age Related ◽

Ex Vivo Tissue ◽

Tlr7 Ligand

Calcific aortic valve stenosis (CAVS) is a common age-related disease characterized by active calcification of the leaflets of the aortic valve. How innate immune cells are involved in disease pathogenesis is not clear. In this study we investigate the role of the pattern recognition receptor Toll-like receptor 7 (TLR7) in CAVS, especially in relation to macrophage subtype. Human aortic valves were used for mRNA expression analysis, immunofluorescence staining, or ex vivo tissue assays. Response to TLR7 agonist in primary macrophages and valvular interstitial cells (VICs) were investigated in vitro. In the aortic valve, TLR7 correlated with M2 macrophage markers on mRNA levels. Expression was higher in the calcified part compared with the intermediate and healthy parts. TLR7+ cells were co-stained with M2-type macrophage receptors CD163 and CD206. Ex vivo stimulation of valve tissue with the TLR7 ligand imiquimod significantly increased secretion of IL-10, TNF-α, and GM-CSF. Primary macrophages responded to imiquimod with increased secretion of IL-10 while isolated VICs did not respond. In summary, in human aortic valves TLR7 expression is associated with M2 macrophages markers. Ex vivo tissue challenge with TLR7 ligand led to secretion of immunomodulatory cytokine IL-10. These results connect TLR7 activation in CAVS to reduced inflammation and improved clearance.

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Use and outcomes of emergency treatment strategies in patients with aortic valve stenosis

European Heart Journal ◽

10.1093/ehjci/ehaa946.2598 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

S.M Piepenburg ◽

K Kaier ◽

C Olivier ◽

M Zehender ◽

C Bode ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Aortic Valve ◽

Aortic Valve Replacement ◽

Hospital Mortality ◽

Valve Replacement ◽

Aortic Valve Stenosis ◽

Emergency Treatment ◽

Funding Source ◽

Artery Disease

Abstract Introduction and aim Current emergency treatment options for severe aortic valve stenosis include surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR) and balloon valvuloplasty (BV). So far no larger patient population has been evaluated regarding clinical characteristics and outcomes. Therefore we aimed to describe the use and outcome of the three therapy options in a broad registry study. Method and results Using German nationwide electronic health records, we evaluated emergency admissions of symptomatic patients with severe aortic valve stenosis between 2014 and 2017. Patients were grouped according to SAVR, TAVR or BV only treatments. Primary outcome was in-hospital mortality. Secondary outcomes were stroke, acute kidney injury, periprocedural pacemaker implantation, delirium and prolonged mechanical ventilation >48 hours. Stepwise multivariable logistic regression analyses including baseline characteristics were performed to assess outcome risks. 8,651 patients with emergency admission for severe aortic valve stenosis were identified. The median age was 79 years and comorbidities included NYHA classes III-IV (52%), coronary artery disease (50%), atrial fibrillation (41%) and diabetes mellitus (33%). Overall in-hospital mortality was 6.2% during a mean length of stay of 22±15 days. TAVR was the most common treatment (6,357 [73.5%]), followed by SAVR (1,557 [18%]) and BV (737 8.5%]). Patients who were treated with TAVR or BV were significantly older than patients with SAVR (mean age 81.3±6.5 and 81.2±6.9 versus 67.2±11.0 years, p<0.001), had more relevant comorbidities (coronary artery disease 52–91% vs. 21.8%; p<0.001), worse NYHA classes III-IV (55–65% vs. 34.5%; p<0.001) and higher EuroSCORES (24.6±14.3 and 23.4±13.9 vs. 9.5±7.6; p<0.001) than SAVR patients. Patients treated with BV only had the highest in-hospital mortality compared with TAVR or SAVR (20.9% vs. 5.1 and 3.5%; p<0.001). Compared with BV only, SAVR patients (adjusted odds ratio [aOR] 0.25; 95% confidence interval [CI] 0.14–0.46; p<0.001) and TAVR patients (aOR 0.37; 95% CI 0.28–0.50; p<0.001) had a lower risk for in-hospital mortality. Conclusion In-hospital mortality for emergency patients with symptomatic severe aortic valve stenosis is high. Our results showed that BV only therapy was associated with highest mortality, which is in line with current research. Yet, there is a trend towards more TAVR interventions and this study might imply that balloon valvuloplasty alone is insufficient. The role of BV as a bridging strategy to TAVR or SAVR needs to be further investigated. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Heart Center Freiburg University, Department of Cardiology and Angiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany

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Loss of smooth muscle SDF-1/CXCL12 leads to cardiac hypertrophy and aortic valve stenosis

European Heart Journal ◽

10.1093/ehjci/ehaa946.3630 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

S.K Ghadge ◽

M Messner ◽

H Seiringer ◽

T Zeller ◽

D Boernigen ◽

...

Keyword(s):

Smooth Muscle ◽

Aortic Valve ◽

Aortic Stenosis ◽

Cardiac Hypertrophy ◽

Smooth Muscle Cells ◽

Aortic Valve Stenosis ◽

Cardiac Fibrosis ◽

Muscle Cells ◽

Funding Source ◽

Lineage Tracking

Abstract Background Stromal cell-derived factor-1 (SDF-1 or CXCL12) and its receptors CXCR4/CXCR7 have prominent role in cardiovascular development and myocardial repair following ischemic injury. Nevertheless, detailed mechanisms of the cell specific role of SDF-1 are poorly understood. Since SDF-1-EGFP lineage tracking revealed high expression of SDF-1 in smooth muscle cells, we aimed to investigate the cell specific role by generating a smooth muscle cell specific SDF-1 (SM-SDF-1−/−) knockout mouse model. Methods SDF-1 expression was analyzed utilizing SDF-1-EGFP reporter mice. Conditional SM-SDF-1 KO mice were generated using Tagln-Cre; SDF-1fl/fl mice. Hearts were analysed with histology and high-resolution episcopic microscopy. Cardiac function was assessed utilizing echocardiography. RNAseq, qRT-PCR, flow cytometry and western blotting were performed. Cardiac fibrosis, apoptotic index, cell proliferation, aortic valve calcification were analyzed. SM-SDF-1−/− mice were treated with the CXCR7 agonist TC14012 (10mg/kg/I.P). Results SDF-1-EGFP lineage tracking and immunofluorescence revealed high expression of SDF-1 particularly in smooth muscle cells and less frequently in perivascular and endothelial cells. Conditional SM-SDF-1−/− mice showed a high pre- and perinatal mortality (50%). Immunohistochemistry of SM-SDF-1−/− mice revealed severe cardiac hypertrophy, associated with increased cardiac fibrosis, apoptotic cell death, thinned and dilated arteries and significantly decreased M2 like CD11b+/CD206+ cells. Echocardiography confirmed concentric hypertrophy, with decreased stroke volume. As a possible reason for cardiac hypertrophy, SDF-1 mutants exhibited aortic stenosis due to aortic valve thickening associated with downregulation of the SDF-1 co-receptor CXCR7. We further noticed increased plasma levels of SDF-1 in aortic stenosis patients suggesting a cardioprotective role. Transcriptome analyses from KO hearts showed an abnormal extracellular matrix (ECM) remodelling with a specific upregulation of the important valve related proteoglycans Versican, Glycan. Western blot analysis revealed activation of AKT and ERK, whereas CXCR7 expression was significantly downregulated in KO mice. To rescue the phenotype we treated KO mice with the CXCR7 agonist (TC14012) which partially attenuated aortic valve remodelling through activation of the ERK signalling pathway. Conclusion Our data suggest that SDF-1 is critically involved in maintaining the homeostasis of the aortic valve by regulating CXCR7 signalling. Pharmacological activation of CXCR7 might be a promising therapeutic target to limit the progression of aortic valve stenosis. Ghadge_SM-SDF-1−/− Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund, Austrian research promotion agency

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Fractional flow reserve and instantaneous wave-free ratio discordance in patients with severe aortic valve stenosis

European Heart Journal ◽

10.1093/ehjci/ehaa946.1276 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

F Yamanaka ◽

K Shishido ◽

S Yokota ◽

N Moriyama ◽

Y Mashimo ◽

...

Keyword(s):

Coronary Artery ◽

Aortic Valve ◽

Aortic Valve Stenosis ◽

Fractional Flow Reserve ◽

Coronary Artery Stenosis ◽

Artery Stenosis ◽

Aortic Valve Area ◽

Fractional Flow ◽

Left Anterior Descending Artery ◽

Flow Reserve

Abstract Background It has been reported that discordance between fractional flow reserve (FFR) and Instantaneous Wave-Free Ratio (iFR) could occur in up to 20% of cases. However, there are no reports regarding discordance between FFR and iFR in patients with severe aortic valve stenosis (AS). Purpose We aimed to investigate the discordance between FFR and iFR in patients with severe AS. Methods Severe AS was defined as an aortic-valve area of ≤1.0 cm2, a mean aortic-valve gradient of 40mmHg or more, or a peak aortic-jet velocity of 4.0 m/s or more. Intermediate coronary artery stenosis was defined as 30% to 70% stenosis (visual estimation). FFR and iFR were calculated in 4 quadrants based on values of FFR ≤0.8 and iFR ≤0.89 (positive discordance; low FFR and high iFR, negative discordance; high FFR and low iFR). Results We examined consecutive 140 patients (164 intermediate coronary artery stenosis vessels). Mean FFR and iFR ± standard deviation was 0.82±0.09 and 0.82±0.14, respectively. The discordance was observed in 48 vessels (29.3%). In the discordant group, most of cases were negative discordance (45 cases, 93.6%). Binary logistic regression analysis showed that left anterior descending artery (Hazard Ratio 3.80; 1.55 to 9.31, p=0.0036) was independently associated with negative discordance. Conclusions In patients with severe AS, the discordance between FFR and iFR could be observed in 29.3% of the vessels, mostly negative discordance. The left anterior descending artery is an independent predictor for negative discordance. Funding Acknowledgement Type of funding source: None

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Abstract 9916: Evaluation of the Best Cut-off Value of Ischemia in Instantaneous Wave-Free Ratio in Patients With Aortic Valve Stenosis

Circulation ◽

10.1161/circ.132.suppl_3.9916 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Hiroyuki Arashi ◽

Junichi Yamaguchi ◽

Tonre Ri ◽

Eiji Shibahashi ◽

Ryosuke Itani ◽

...

Keyword(s):

Aortic Valve ◽

Aortic Valve Stenosis ◽

Coronary Stenosis ◽

Pressure Ratio ◽

Aortic Valve Area ◽

Fractional Flow ◽

Clinical Value ◽

Flow Reserve ◽

Significant Difference ◽

The Mean

Background: Instantaneous wave-free ratio (iFR) is a vasodilator free index calculated using trans-lesional pressure ratio during a specific period of diastole that is called “wave-free period”, and reported to have a good correlation with fractional flow reserve (FFR). In patients with severe aortic valve stenosis (AS), evaluation of intermediate coronary stenosis by FFR using vasodilators is thought to be a contraindication in some situations. Moreover, previous studies reported unique coronary flow pattern during diastolic phase in patients with AS. To date, there is no report claiming the correlation of iFR and FFR in this population. The purpose of the present study was to examine the clinical value of iFR in patients with AS. Method and Results: We examined consecutive 154 patients (with 214 stenosis) whose iFR and FFR were measured simultaneously. The mean age of AS patients (n=10, mean aortic valve area: 0.75 ± 0.42cm2) was higher than non-AS patients (n=144). Other patients’ characteristics are shown in Table 1. The mean iFR value in AS patients was significantly lower than that of non-AS patients, despite no significant difference was observed in the mean FFR value and % diameter stenosis (Table 2). iFR showed a good correlation with FFR in AS patients (Figure 1) and the best cut-off value of iFR in receiver operator curve analysis to predict FFR ≤ 0.8 was 0.73 in AS patients (AUC 0.84, sensitivity 0.8, specificity 0.86, p=0.016; Figure 2), whereas, 0.90 in non-AS patients. Conclusion: The present study demonstrated the good correlation between iFR and FFR in AS patients. Besides, the value below 0.73 of iFR was thought to be a predictor of myocardial ischemia in AS patients, which was lower than standard predictive range of ischemia in iFR. Vasodilator-free assessment by iFR may have potential benefits in evaluating intermediate coronary stenosis in patients with AS.

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Abstract 6143: Regression of Aortic Valve Stenosis by ApoA-I Mimetic Peptide Infusions in Rabbits

Circulation ◽

10.1161/circ.118.suppl_18.s_1070 ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

David Busseuil ◽

Yanfen Shi ◽

Mélanie Mecteau ◽

Geneviéve Brand ◽

Teodora Avram ◽

...

Keyword(s):

Aortic Valve ◽

Aortic Stenosis ◽

Aortic Valve Stenosis ◽

White Male ◽

Treated Group ◽

Saline Control ◽

Control Group ◽

Clinical Approach ◽

Aortic Valve Area ◽

Mimetic Peptide

Purpose : Aortic valve stenosis is the most common valvular heart disease, and standard curative therapy remains open-heart surgical valve replacement. The aim of our experimental study was to determine if ApoA-I mimetic peptide infusions could induce regression of aortic valve stenosis. Methods : Twenty-seven New-Zealand White male rabbits received a cholesterol-enriched diet and vitamin D 2 until significant aortic valve stenosis was detected by echocardiography. The enriched diet was then stopped to mimic cholesterol-lowering therapy and animals were randomized to receive saline (control group, n =14) or an ApoA-I mimetic peptide (treated group, n =13), 3 times per week for 2 weeks. Serial echocardiograms and post mortem valve histology were performed. Results : Aortic valve area improved significantly in the treated group compared to controls after 7 days (20.9±0.9 mm 2 vs. 18.2±0.6 mm 2 , P <0.0001) (corresponding to increases of 15.9% and 1.9%), 10 days (21.5±1.0 mm 2 vs. 19.5±0.6 mm 2 , P =0.0032) (increases of 19.2% vs. 9.1%), and 14 days of treatment (22.4±0.9 mm 2 vs. 20.4±0.6 mm 2 , P =0.0028) (increases of 24.4% vs. 14.2%). Likewise, aortic valve thickness decreased by 19% after 14 days of treatment in the treated group (0.951±0.070 mm at baseline vs. 0.768±0.074 mm at follow-up) whereas it was unchanged in controls ( P <0.0001). Histological analysis revealed that lesion extent at the base of valve leaflets and sinuses of Valsalva was smaller in the treated compared to control group (52.8±12.5% vs. 66.7±9.9%, P =0.032). The ApoA-I mimetic peptide treatment also leads to a reduction in aortic valve calcifications as revealed by the loss of the positive relationship observed in the control group ( r =0.87, P =0.004) between calcifications area and aortic valve thickness. Conclusions : Infusions of an ApoA-I mimetic peptide lead to regression of experimental aortic valve stenosis. These positive results justify the further testing of HDL-based therapies in patients with valvular aortic stenosis. Regression of aortic stenosis, if achieved safely, could transform our clinical approach of this disease.

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PREDICTORS OF CALCIFIC AORTIC VALVE STENOSIS PROGRESSION AS MEASURED BY CHANGE IN PEAK VELOCITY: A META-ANALYSIS AND META-REGRESSION

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(20)32799-6 ◽

2020 ◽

Vol 75 (11) ◽

pp. 2172

Author(s):

Navneet Sharma ◽

Sareena George ◽

Ramsey Kalil ◽

Prateek Sharma ◽

Paul Kim ◽

...

Keyword(s):

Aortic Valve ◽

Aortic Valve Stenosis ◽

Peak Velocity ◽

Meta Analysis ◽

Meta Regression

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Aortic valve calcification among elderly males from the general population, associated echocardiographic findings, and clinical implications

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jeab182 ◽

2021 ◽

Author(s):

Lida Khurrami ◽

Jacob Eifer Møller ◽

Jes Sanddal Lindholt ◽

Jordi Sancez Dahl ◽

Maise Hoeigaard Fredgart ◽

...

Keyword(s):

Aortic Valve ◽

General Population ◽

Peak Velocity ◽

Left Ventricular ◽

Steady Increase ◽

Aortic Valve Area ◽

Aortic Valve Calcification ◽

Valve Calcification ◽

Background Population ◽

Echocardiographic Findings

Abstract Aims Aortic valve calcification (AVC) detected by non-contrast computed tomography (NCCT) associates with morbidity and mortality in patients with aortic valve stenosis. However, the importance of AVC in the general population is sparsely evaluated. We intend to describe the associations between AVC score on NCCT and echocardiographic findings as left atrial (LA) dilatation, left ventricular (LV) hypertrophy, aortic valve area (AVA), peak velocity, mean gradient, and aortic valve replacement (AVR) in a population with AVC scores ≥300 AU. Methods and results Of 10 471 males aged 65–74 years from the Danish Cardiovascular Screening trial (DANCAVAS), participants with AVC score ≥300 AU were invited for transthoracic echocardiography and 828 (77%) of 1075 accepted the invitation. AVC scores were categorized (300–599, 600–799, 800–1199, and ≥1200 AU). AVR was obtained from registries. AVC was significantly associated with a steady increase in LA dilation (10.5%, 16.3%, 15.8%, 19.6%, P = 0.031), LV hypertrophy (3.9%, 6.6%, 8.9%, 10.1%, P = 0.021), peak velocity (1.7, 1.9, 2.1, 2.8 m/s, P = 0001), mean gradient (6, 8, 11, 19 mmHg, P = 0.0001), and a decrease in AVA (2.0, 1.9, 1.7, 1.3 cm2, P = 0.0001). The area under the curve was 0.79, 0.93, and 0.92 for AVA ≤1.5 cm2, peak velocity ≥3.0 m/s, and mean gradient ≥20 mmHg, respectively, and the associated optimal AVC score thresholds were 734, 1081, and 1019 AU. AVC > 1200 AU was associated with AVR (P < 0.0001). Conclusion Among males from the background population, increasing AVC scores were associated with LA dilatation, LV hypertrophy, AVA, peak aortic velocity, mean aortic gradient, and AVR.

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AORTIC VALVE AREA/PEAK VELOCITY DISCORDANCES IN BICUSPID AORTIC VALVES

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(18)32557-9 ◽

2018 ◽

Vol 71 (11) ◽

pp. A2016

Author(s):

Matthew W. Parker ◽

Samuel Stone ◽

Brooks Willar ◽

Adedotun Ogunsua ◽

Bryon Gentile ◽

...

Keyword(s):

Aortic Valve ◽

Peak Velocity ◽

Aortic Valve Area ◽

Aortic Valves ◽

Bicuspid Aortic Valves ◽

Valve Area

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Serum copeptin might improve risk stratification and management of aortic valve stenosis: a review of pathophysiological insights and practical implications

Therapeutic Advances in Cardiovascular Disease ◽

10.1177/1753944719826420 ◽

2019 ◽

Vol 13 ◽

pp. 175394471982642

Author(s):

Kenan Yalta ◽

Orkide Palabiyik ◽

Muhammet Gurdogan ◽

Yekta Gurlertop

Keyword(s):

Aortic Valve ◽

Aortic Valve Stenosis ◽

Cardiac Death ◽

Surrogate Marker ◽

Adverse Outcomes ◽

Aortic Valve Area ◽

Improve Risk Stratification ◽

Objective Risk ◽

Practical Implications ◽

Valve Area

Over recent decades, the prevalence of aortic valve stenosis (AVS) has been constantly increasing possibly owing to the aging of general population. Severe AVS as determined by an aortic valve area (AVA) of <1 cm2 has been regarded as a serious clinical condition potentially associated with a variety of adverse outcomes, including sudden cardiac death (SCD). However, patients with severe AVS (in the absence of overt high-risk features) are usually evaluated and managed exclusively based on symptomatology or imperfect prognostic tools including exercise testing and biomarkers, with a potential risk of mismanagement, suggesting the need for further objective risk stratifiers in this setting. Within this context, copeptin (C-terminal pro-vasopressin), a novel neurohormone widely considered as the surrogate marker of the arginine–vasopressin (AVP) system, may potentially serve as a reliable prognostic and therapeutic guide (e.g. timing of aortic valvular intervention) in patients with severe AVS largely based on its hemodynamic, fibrogenic as well as autonomic implications in these patients. Accordingly, the present paper aims to discuss clinical and pathophysiological implications of copeptin in the setting of AVS along with a summary of biomarkers and other prognostic tools used in this setting.

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