Frailty is associated with chronic inflammation and pro-inflammatory monocyte subpopulations

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Cybularz ◽  
S Wydra ◽  
K Berndt ◽  
D Poitz ◽  
P Barthel ◽  
...  
Keyword(s):  
Intensive Care ◽  
Aortic Valve ◽  
Chronic Inflammation ◽  
Aortic Valve Stenosis ◽  
Apache Ii Score ◽  
Funding Source ◽  
High Grade ◽  
Frailty Status ◽  
Inflammatory Monocytes ◽  
Monocyte Subpopulations

Abstract Introduction Patients with frailty represent an increasing patient group in the intensive care medicine. A connection between frailty and inflammation has been suggested. An increased mortality rate in patients with high grade aortic valve stenosis (AS) and frailty, who underwent Transcatheter Aortic Valve Implantation (TAVI) has been observed. A systemic inflammatory reaction in the intensive care unit in the first days after TAVI is a positive predictive factor for an unfavorable outcome. Exact mechanisms are still not fully explained. Monocyte subpopulations are associated with both cardiovascular diseases and a high APACHE II score in critically ill patients. Purpose This study investigates the correlation between frailty and cellular and systemic inflammatory mechanisms and mortality after TAVI. Methods We examined 120 patients with symptomatic AS who underwent TAVI. Before the implantation, frailty status has been assessed. In all patients a flow cytometry analysis has been performed. Monocyte subpopulations were defined as follows: Mon1 (CD14++CD16–), Mon2 (CD14++CD16+) and Mon3 (CD14+CD16++). Expression of CD11b has been measured as a marker for monocyte activation. Pro-inflammatory cytokines such as interleukin IL-8, as well as CRP have been measured with Cytometric Bead Array or standard laboratory methods. Results After 3 months 15 of 120 patients died, primarily without relevant dysfunction of the implanted aortic valve. In 8 of 15 (53%) of the deceased patients and 20 of 100 (19%) of the surviving patients, frailty could be diagnozed before TAVI (p=0.003). Patients with frailty showed prior to TAVI signs of chronic inflammation: elevated CRP (3.7 vs. 5.9 mg/l, p=0.001) and elevated levels of considered as pro-inflammatory Mon2 monocytes (37 vs. 53, p=0.001). Expression of CD11b and IL-8 showed an increasing trend in patients with frailty. Frailty, the monocyte markers, IL-8 and CRP prior to TAVI correlated with increased early mortality after TAVI. Conclusion A considerable number of elderly patients with high grade aortic valve stenosis can be described as frail. This syndrome is associated with increased mortality and with signs of chronic systemic inflammation and pro-inflammatory monocytes. Funding Acknowledgement Type of funding source: Private hospital(s). Main funding source(s): Heart Center Dresden

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

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

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

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S.T Niepmann ◽  
A.S Boucher ◽  
M Bulic ◽  
P.R Goody ◽  
F Jansen ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Stenosis ◽  
Histological Analysis ◽  
Peak Velocity ◽  
Macrophage Infiltration ◽  
Funding Source ◽  
Aortic Valve Area ◽  
Mrna Levels ◽  
Toll Like Receptor ◽  
Age Related

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)

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

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

The role of noncoding RNAs during aortic valve stenosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
P.R Goody ◽  
D Christmann ◽  
M.R Hosen ◽  
D Nehl ◽  
D Goody ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Aortic Valve ◽  
Disease Progression ◽  
Aortic Valve Stenosis ◽  
Noncoding Rnas ◽  
Funding Source ◽  
Valvular Interstitial Cells ◽  
Valve Tissue ◽  
Valvular Calcification

Abstract Background Aortic valve stenosis (AVS) is the most common valve disease worldwide. Thought to be a purely degenerative disease, it is now clear that shear stress/endothelial dysfunction, lipid deposition and inflammation lead to calcification and stenosis of the valve. There is evidence, that extracellular vesicles (EVs) are actively involved in calcification processes. Practically all cells, including endothelial cells, can generate EVs, which can be shed into the blood stream and into the interstitial space. EVs contain lipids, proteins and nucleic acids, including noncoding RNAs (ncRNAs). EVs can be taken up by acceptor cells and their cargo, especially the ncRNA content, can change the phenotype of these cells. NcRNAs have been shown to have protective and damaging properties in AVS, which can lead to disease progression. EVs are actively involved in atherosclerosis and vascular calcification, but their role during AVS formation remains largely unknown. Purpose We hypothesize, that EV-derived ncRNAs play a crucial role during calcification of the aortic valve through regulation of endothelial to mesenchymal transition (EndMT) and calcification of valvular interstitial cells. Methods and results In initial screening experiments, we investigated ncRNA (micro RNA, miRNA and long noncoding RNA, lncRNA) content in aortic valve tissue from explanted human aortic valves from patients undergoing surgical aortic valve replacement. There is a differential expression of miRNAs and lncRNAs in aortic valve tissue from patients with AVS and patients without AVS. We could also show a differential packaging of ncRNAs into EVs generated from patient aortic valve tissues. Furthermore, ncRNA expression in aortic valve tissue is altered in a “wire-injury” mouse model of AVS. We can demonstrate in vitro that EVs and their content can be transferred from valvular endothelial cells (VECs) to valvular interstitial cells (VICs) and vice versa. Additionally, we have established an isolation method of VECs and VICs from human samples. To identify ncRNAs involved in EndMT, we are investigating the effect of laminar and pulsatile flow on the expression of ncRNAs in vitro. We can demonstrate that different flow patterns lead to a vast change in ncRNA expression in primary VECs. Downstream effects of identified ncRNAs are currently under investigation in our in vitro calcification and EndMT models. Transfection of VICs with miRNA mimics and inhibitors and lentiviral transduction of our identified targets lead to an altered calcification potential of valve cells. Conclusion The analysis of the cell type specific expression of ncRNAs and the intercellular communication via EVs will greatly help our understanding of the pathomechanisms leading to valvular calcification. Pathway analysis will generate new targets that could be used to develop therapeutics to ameliorate disease progression. EV-based miRNA mimics and inhibitors could be used to treat valvular calcification. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft, TRR259; Else-Kröner-Fresenius

scholarly journals Modified New Zealand rabbit model produces severe aortic valve calcification and stenosis via extracellular membranous particles

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Anousakis-Vlachochristou ◽  
A Varela ◽  
M Kyriakidou ◽  
S Parimalam ◽  
S Badilescu ◽  
...  
Keyword(s):  
New Zealand ◽  
Aortic Valve ◽  
Optical Imaging ◽  
Aortic Valve Stenosis ◽  
Rabbit Model ◽  
Alcoholic Solution ◽  
Funding Source ◽  
Vitamin D2 ◽  
Calcium Cations ◽  
Ft Ir

Abstract Background/Purpose In aortic valve stenosis calcification begins with nucleation on extracellular vesicles. In order to study early-stage disease, validated animal models are needed. The Drolet rabbit model is relevant due to tricuspid valve, but failed to consistently produce stenosis probably due to regimen administration. We compared a modified rabbit model and investigated the mechanisms and patterns of calcification. Methods New Zealand rabbits introduced to normal chaw+1% cholesterol+8750 IUs Vitamin D2/kg (Sigma) daily, in olive oil given in a bisquit vs control animals, for 8 weeks. Aortic valve area (AVA) and mean gradient (meanGr) was assessed with echocardiography (Vivid 7, M3S transducer, GE). At 8 weeks animals were sacrificed and valves were snap-frozen to −80°C. From each animal, one cusp was analyzed with Fourier-Transformed Infrared Spectroscopy (FT-IR, Nicolet 6700 spectrometer, OMNIC 7.3 software), another cusp was processed in alcoholic solution and the third was fixed 0.5 μm thin on 4% PFA; supernatant and tissue respectively examined with multispectral optical imaging. Valves from patients with severe stenosis were used for qualitative comparisons. Results At 8 weeks versus baseline, AVA reduced (0.5 cm2 to 0.3 cm2) and meanGr increased (1.1 to 2.95 mmHg, p<0.05), in control was unchanged. FT-IR vibrations in the region of 1800–800 cm–1 demonstrated changes in the protein structure and deposition of CaCO3 and non-hydroxyapatite Ca3(PO4)2 identical to patients' lesions. Multispectral optical imaging of supernatants revealed numerous membranous particles and conductivity analysis indicated calcium cations accumulation on the phospholipids of membrane. The tissue images confirmed the degradations and dendrimer-like depositions of calcium cations most likely on carbonates of amino acids. Conclusions The modified high-fat-vitamin D2 rabbit model produces aortic valve stenosis, with chemically identical mineralization to human lesion. Multispectral photonics demonstrate the presence of calcified membranous extracellular particles, a hallmark of cardiovascular calcification. Dendrimer-like depositions correspond to growing deposits. The model is suitable as a research platform purposed for aortic valve stenosis. Figure 1. A: Image from alcoholic solution supernatant. The bright spots have high conductivity due to Ca 2+ deposition. B: ImageJ surface plot of circulated region confirms calcification. C: 3D-plot illustrates mineralization of membranes. D: 3D-plot of human aortic valve. E: Hypermicroscopic image of rabbit valve tissue: dendrimer-like and mineral cation deposits. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): National and Kapodistrian University of Athens, Greece; Concordia University, Montreal, Canada

scholarly journals Plasma lipids and risk of aortic valve stenosis: a Mendelian randomization study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Nazarzadeh ◽  
A.-C Pinho-Gomes ◽  
Z Bidel ◽  
A Dehghan ◽  
D Canoy ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Mitral Regurgitation ◽  
Aortic Stenosis ◽  
Aortic Valve Stenosis ◽  
Ldl Cholesterol ◽  
Mendelian Randomization ◽  
Density Lipoprotein ◽  
Funding Source ◽  
Causal Association ◽  
Lipid Levels

Abstract Background Aortic valve stenosis is commonly considered a degenerative disorder with no recommended preventive intervention, with only valve replacement surgery or catheter intervention as treatment options. Purpose We sought to assess the causal association between exposure to lipid levels and risk of aortic stenosis. Methods Causality of association was assessed using two-sample Mendelian Randomization (MR) framework through different statistical methods. MR approach uses instrumental variable analysis to mimic the randomization process that underpins causal inference in clinical trials. It takes advantage of the naturally-occurring random allocation of alleles inherited by offspring from their parents during the formation of the zygote. We retrieved summary estimations of 157 genetic variants that have been shown to be associated with plasma lipid levels in the Global Lipids Genetics Consortium that included 188,577 participants, mostly European ancestry, and genetic association with aortic stenosis as the main outcome from a total of 432,173 participants in the UK Biobank. Secondary negative control outcomes included aortic regurgitation and mitral regurgitation. Results The odds ratio (OR) for developing aortic stenosis per unit increase in lipid parameter was 1.52 (95% confidence interval [CI], 1.22 to 1.90; per 0.98 mmol/L) for low-density lipoprotein (LDL) cholesterol, 1.03 (95% CI, 0.80 to 1.31; per 0.41 mmol/L) for high-density lipoprotein (HDL) cholesterol, and 1.38 (95% CI 0.92 to 2.07; per 1 mmol/L) for triglycerides. There was no evidence of a causal association between any of the lipid parameters and aortic or mitral regurgitation. Conclusion Lifelong exposure to high LDL-cholesterol increases the risk of symptomatic aortic stenosis, suggesting that LDL-lowering treatment may be effective in its prevention. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Dissolving cholesterol crystals reduces aortic valve stenosis development in mice

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S.T Niepmann ◽  
M Lenart ◽  
N Willemsen ◽  
P Duewell ◽  
D Luetjohann ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Stenosis ◽  
Serum Cholesterol ◽  
Cholesterol Metabolism ◽  
Therapeutic Option ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Funding Source ◽  
Aortic Valves ◽  
Cholesterol Crystals

Abstract Background Aortic valve stenosis (AS) is the most common valve disease worldwide and is associated with a very high morbidity and mortality. Until today, aortic valve replacement is the only therapeutic option available. Analysis of explanted human aortic valves has shown that atherosclerosis-like lesions, that contain cholesterol crystals (CC), are present in stenotic aortic valve cusps. It has been demonstrated that CCs can activate the NLRP3 inflammasome and hereby trigger a complex, IL-1b driven, inflammatory response. 2-hydroxypropyl-β-cyclodextrin (CD) is a cyclic oligosaccharide that can increase the solubility of CCs, which results in a reduction of CC-load and therefore could inhibit the pro-inflammatory immune response. Methods Severe AS was induced in 10 weeks old C57BL/6-J (WT) and Apolipoprotein-E-deficient (ApoE) mice. Acoronary springwire was used to induce an endothelial injury under echocardiographic guidance. AS development was confirmed via ultrasound examinations. ApoE mice were fed a cholesterol-rich western diet and concomitantly received daily injections of 2g/kg/d CD via subcutaneous injection. CCs were visualized with laser reflection confocal microscopy. Serum cholesterol analysis were performed via mass GC-MS-SIM. Results In order to evaluate whether hyperlipidemia aggravates AS development, WT and ApoE mice were fed a cholesterol-rich diet and subjected to our model of wire-induced AS. Trans-aortic valve peak velocity levels of ApoE mice were significantly increased six weeks after injury compared to WT mice. Histological analysis of these mice showed large CC-deposits in the aortic valves of ApoE mice. Next, CC solubility was increased in a group of ApoE mice, control mice only received PBS injections. Interestingly, mice treated with CD displayed a significantly reduced peak blood velocity over the aortic valve compared to PBS mice. Left ventricular ejection fraction remained unchanged. Serum cholesterol analysis was performed to analyze the effect of CD on cholesterol metabolism. 27-hydroxycholesterol, an endogenous oxysterol of cholesterol metabolism, which reduces the potential for the conversion of free cholesterol into crystals was significantly increased in CD treated mice. The levels of cholesterol precursors were unchanged, indicating that CD doesn't influence de-novo synthesis of cholesterol. Intestinal absorption of cholesterol was also not affected by CD, as assessed by quantification of phytosterols in the serum of CD and PBS treated mice. Conclusion These results underline the importance of hyperlipidemia in the pathogenesis of AS. Particularly CCs seem to act as an important inflammatory trigger in the development of AS. Increasing the solubility of cholesterol through CD reduces AS development in mice and could, as it is already considered safe in human, act as a possible therapeutic option. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): DFG, German Research Foundation

Investigation of the optimal rabbit model for aortic valve stenosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Anousakis-Vlachochristou ◽  
M Katsa ◽  
A Panara ◽  
A Varela ◽  
M Kyriakidou ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Stenosis ◽  
Rabbit Model ◽  
Public Institution ◽  
Funding Source ◽  
Vitamin D2 ◽  
Group A ◽  
Ft Ir ◽  
Group B ◽  
Group D

Abstract Background/Purpose Anatomically, hemodynamically relevant and validated animal models for aortic valve stenosis are of great need. Drolet rabbit model with tricuspid anatomy produced conflicting results for unclear reasons. We hypothesized that limitations concentrate in the regimen administration. We sought to evaluate multiple doses, ways of administration and time periods. Methods We included New Zealand rabbits in 4 groups: Group A (Drolet): was fed with normal chaw (nc)+0.5% cholesterol (chol)+3500 IUs Vitamin D2/kg (VD2, ergocalciferol, Sigma) in water daily for 12 weeks (wks), Group B: nc+0.5%chol+3500 IUs/kg VD2 in oil incorporated in a bisquit daily for 8 wks, Group C: nc+0.5%chol+8750 IUs/kg VD2 in oil-biscuit for 8 wks, Group D: nc+0.5%chol+17500 IUs VD2 in oil-biscuit for 8 wks vs controls (fed only with nc). After 12 and 8 wks the rabbits were sacrificed. Aortic valve area (AVA) and mean gradient (meanGr) were assessed with echocardiography (Vivid 7, M3S transducer, GE) and serum obtained, at baseline and before sacrifice. VD2 levels were evaluated through Chemiluminescent Microparticle Immuno Assay (CMIA, Abbott) and liquid chromatography – tandem mass spectrometry (LC-APCI-MS/MS). Animals received i.v. 18F-NaF one hour before sacrifice and valve was ex-vivo imaged with microPET/CT (Mediso nanoScan). Aortic cusps were analyzed with Fourier-Transformed Infrared Spectroscopy (FT-IR, Nicolet 6700 spectrometer, OMNIC 7.3 software). Valves from surgical patients with severe stenosis served for comparison purposes. Results In Group A at 12 wks AVA and meanGr remained unchanged but biomineralization was detected with FT-IR with vibrations in the region of 1800–800 cm–1 demonstrating the deposition of CaCO3 and non-hydroxyapatite Ca3(PO4)2 identical to human lesion. Calcification was detected on cusps with 18F-NaF. VD2 levels were out of upper detection range with CMIA due to cross reaction, whereas all samples measured through LC-MS/MS were below the detection limit of the method (<19,1 ng/mL). Significant Assessment heterogeneity (RSD=27%) was observed on VD2 water regimen. In Group B, AVA changed from 0.5 cm2 to 0.4 cm2 and meanGr increased from 1.1 to 2.1 mmHg, p<0.05 and in Group C AVA: 0.5 cm2 to 0.3 cm2 and meanGr: 1 to 2.95 mmHg, p<0.05, while VD2 serum concentration were 511 ng/mL. In Group D animals die unexpectedly at 2 weeks, with autopsy revealing massive myocardial hypertrophy of the left ventricle (LVH) without compromise of the aortic valve. Conclusions The modified diet produces aortic valve stenosis and biomineralization detectable with 18F-NaF, chemically identical to human lesion. Very high doses of Vitamin D2 directly produce LVH, possibly leading to arrythmiogenesis. The modified high-fat-vitamin D2 rabbit model proved suitable for translational research of aortic valve stenosis disease. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): National and Kapodistrian University of Athens

Sign in / Sign up

Export Citation Format

Share Document