Cardiac pressure overload exposes hidden anthracycline-induced cardiotoxicity: results from a preclinical large-animal trial

Aim

The purpose of this work is to elucidate if low cumulative doxorubicin doses has a differential cardiac impact in pigs with or without pre-existing LV pressure overload. Impact of interventions on LV anatomy, function and tissue composition was evaluated by serial cardiac magnetic resonance (CMR). At the end of the in vivo protocol, hearts were processed to evaluate differential molecular pathways in both groups.

Methods

A total of 95 pigs were included. 52 animals underwent supravalvular aortic banding to generate LV hypertrophy, while another did not. 4 months after banding (a time where LV hypertrophy is prominent), animals in both groups were randomized to receive intravenous doxorubicin (1 mg/kg once per week, for 5 weeks) or saline. Thus, 4 study groups (N=15–22 per group) comprised the study population (banding yes/no, doxorubicin yes/no). All individuals underwent to serial Cardiac Magnetic Resonance exams every month and were sacrificed fo ex vivo analysisat 4 months after doxorubicin injections. To discriminate between doxorubicin effect in banding/no banding groups but also the effect of banding in doxorubicin protocols, t-test was used for two-group comparisons after two-way ANOVA test. Differences were considered statistically significant at p<0.05. Logrank test was performed to compare survival curves.

Results

Pigs receiving doxorubicin after cardiac pressure overload showed an increased mortality compared with the other groups (p=0.006). Only this group developed a progressive cardiotoxicity phenotype, characterized as a significant decline in cardiac function compared with control operated animals (49.7% ± 8.1 vs 79.6% ± 6.7, p<0.001), but also with non-operated pigs receiving the same anthracycline regime (vs 63.9% ± 4, p<0.001). Cardiac deterioration was based mainly on systolic dysfunction compared with control operated animals (38.2 ml indexed ± 3.5 vs 13.6±6.6, p=0.01) and non-operated pigs treated with doxorubicin (vs 26.6 ml indexed ± 6.6, p<0.001). In-vivo CMR tissue characterization revealed elevation on T2 relaxation times compared with Control animals (46.2 ms ± 3.5 vs 41.8±2.7, p=0.04) with no Extracellular Volume expansion. Ex-vivo histological analyses showed presence of intra-cardiomyocyte vacuolization in the Banding + DOXO group (p=0.01). Regarding mitochondrial phenotype, animals with Banding + DOXO exhibited a fragmented phenotype with extremely damaged mitochondria. Animals with only aortic banding exhibit increasing cardiac hyperkinesia and cardiac hypertrophy at the end of the study.

Conclusion(s)

We demonstrated that a very low dosage of doxorubicin is enough to exert cardiotoxicity in a pressure overload scenario. Characterized as a deterioration in cardiac function, myocardial edema, classical histological lesions and mitochondrial damage. Providing preclinical evidence that modest anthracycline protocols may be harmful for patients with cardiac comorbidities.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ERC MATRIX

Remote ischaemic conditioning: defining critical criteria for success-report from the 11th Hatter Cardiovascular Workshop

The Hatter Cardiovascular Institute biennial workshop, originally scheduled for April 2020 but postponed for 2 years due to the Covid pandemic, was organised to debate and discuss the future of Remote Ischaemic Conditioning (RIC). This evolved from the large multicentre CONDI-2-ERIC-PPCI outcome study which demonstrated no additional benefit when using RIC in the setting of ST-elevation myocardial infarction (STEMI). The workshop discussed how conditioning has led to a significant and fundamental understanding of the mechanisms preventing cell death following ischaemia and reperfusion, and the key target cyto-protective pathways recruited by protective interventions, such as RIC. However, the obvious need to translate this protection to the clinical setting has not materialised largely due to the disconnect between preclinical and clinical studies. Discussion points included how to adapt preclinical animal studies to mirror the patient presenting with an acute myocardial infarction, as well as how to refine patient selection in clinical studies to account for co-morbidities and ongoing therapy. These latter scenarios can modify cytoprotective signalling and need to be taken into account to allow for a more robust outcome when powered appropriately. The workshop also discussed the potential for RIC in other disease settings including ischaemic stroke, cardio-oncology and COVID-19. The workshop, therefore, put forward specific classifications which could help identify so-called responders vs. non-responders in both the preclinical and clinical settings.

Regional analysis of inflammation and contractile function in reperfused acute myocardial infarction by in vivo 19F cardiovascular magnetic resonance in pigs

Inflammatory cell infiltration is central to healing after acute myocardial infarction (AMI). The relation of regional inflammation to edema, infarct size (IS), microvascular obstruction (MVO), intramyocardial hemorrhage (IMH), and regional and global LV function is not clear. Here we noninvasively characterized regional inflammation and contractile function in reperfused AMI in pigs using fluorine (¹⁹F) cardiovascular magnetic resonance (CMR). Adult anesthetized pigs underwent left anterior descending coronary artery instrumentation with either 90 min occlusion (n = 17) or without occlusion (sham, n = 5). After 3 days, in surviving animals a perfluorooctyl bromide nanoemulsion was infused intravenously to label monocytes/macrophages. At day 6, in vivo ¹H-CMR was performed with cine, T2 and T2* weighted imaging, T2 and T1 mapping, perfusion and late gadolinium enhancement followed by ¹⁹F-CMR. Pigs were sacrificed for subsequent ex vivo scans and histology. Edema extent was 35 ± 8% and IS was 22 ± 6% of LV mass. Six of ten surviving AMI animals displayed both MVO and IMH (3.3 ± 1.6% and 1.9 ± 0.8% of LV mass). The ¹⁹F signal, reflecting the presence and density of monocytes/macrophages, was consistently smaller than edema volume or IS and not apparent in remote areas. The ¹⁹F signal-to-noise ratio (SNR) > 8 in the infarct border zone was associated with impaired remote systolic wall thickening. A whole heart value of ¹⁹F integral (¹⁹F SNR × milliliter) > 200 was related to initial LV remodeling independently of edema, IS, MVO, and IMH. Thus, ¹⁹F-CMR quantitatively characterizes regional inflammation after AMI and its relation to edema, IS, MVO, IMH and regional and global LV function and remodeling.

Impact of malnutrition on the relationship between obesity and mortality in patients with atrial fibrillation

Introduction

A protective effect of obesity has been previously reported in patients with atrial fibrillation (AF) – the so-called `obesity paradox”. Nutritional status could behave as a confounding factor, but there are no studies that analyze the interaction of malnutrition in the relationship between obesity and mortality in AF patients.

Aim

The objective of this study was to determine the impact of nutritional status on the relationship between body mass index (BMI) and mortality in AF patients.

Methods

A retrospective, multicenter, population-based cohort study of patients with diagnosis of AF from January 1, 2014 to December 31, 2017, in Vigo, Spain, was conducted. We created three separate groups according to BMI (normal-weight, overweight, and obesity) and three separate cohorts based on nutritional status according to CONUT score (good nutrition, mild malnutrition, and moderate-severe malnutrition).

The primary outcome was all-cause mortality. Secondary outcomes included embolic events (systemic embolism and stroke) and major bleeding. A combined endpoint of mortality, embolic and haemorrhagic events was assessed (clinical net outcome).

Results

A total of 14,849 AF patients aged ≥75 years (75.6±10.3 years, 50.9% women) were followed-up during 44.4±1.8 years. Overweight and obesity was observed in 42.6% and 46.0%, respectively, whereas malnutrition was observed in 34.3%. Malnutrition rates were lower as BMI increased: from 48.1% in patients with underweight, to 36.8%, 35.1% and 33.0% in patients with normal weight, overweight, and obesity, respectively (p-value <0.001 for the trend). BMI was inversely associated with mortality (HR 0.96, 95% CI 0.95–0.97; p<0.001) in the univariate analysis; however, this association was lost when adjusted analysis by nutritional status was performed (HR 0.99, 95% CI 0.99–1.00; p=0.285). Thus, neither overweight nor obesity were predictors of mortality nor net outcome when we adjusted by nutritional status: after stratifying for presence of malnutrition, survival of patients with a BMI>25 kg/m2 was similar to that of patients with BMI ≤25 kg/m2. Regarding to nutritional status, both mild and moderate-severe malnutrition were associated with higher rates of mortality, stroke/systemic embolism and bleeding in all BMI groups (normal-weight, overweight and obesity).

In this real-world observational study, we have assessed the interaction of nutritional status in the association between BMI and prognosis of AF patients. We concluded that 1) Malnutrition is common in AF patients, even among patients with overweight and obesity; 2) Malnutrition is a strong predictor of mortality in patients with AF; and 3) BMI was not associated with worse prognosis after adjusting for nutritional status.

Conclusion

The analysis of a large population of AF patients showed that the association between improved mortality and obesity/overweight is confounded by malnutrition status.

Funding Acknowledgement

Type of funding sources: None. Impact of nutrition status and weightClinical outcomes in different groups

Cardiovascular predictors associated with poor short-term prognosis in patients diagnosed with SARS-CoV-2 in Spain

Background

On January 2020, the first patient with coronavirus 2 (SARS-CoV-2) was detected in Spain. Since then, 3 280 000 cases have been confirmed and 75.305 people have died. We aimed to clarify the epidemiological and clinical characteristics related with poor short-term prognosis in patients diagnosed with SARS-CoV-2.

Methods

Observational, retrospective single-center study including consecutive patients (≥40yo) diagnosed with SARS-CoV-2 through PCR, since March 2nd to 20th 2020 in our center in Spain. The primary endpoint (PE) was the combined of all-cause death or need for orotracheal intubation within the first 30 days of infection symptoms.

Results

704 patients were included (table). A follow-up period of thirty-days was fully completed in 692 of 704 patients (98.3%). At the end of this period, 148 patients (21.4%) met the PE; they were older, more frequently male, obese and smokers. Patients who met the PE had a higher prevalence of hypertension, diabetes, dyslipidemia, ischemic heart disease, heart failure, peripheral and cerebrovascular disease, cancer and lung pathologies. They received more frequently therapies with renin-angiotensin system inhibitors, betablockers, calcium channel blockers and statins, as well as antiplatelet and anticoagulant therapies

Multivariate analysis showed that age (OR 1.99 for every 10 years, 95% CI [1.637–2.4], p<0.001), female sex (OR 0.49, [0.30–0.80], p=0.004), diabetes (OR 2.09, [1.17–3.71], p=0.012), lung disease (OR 1.99, [1.14–3.44], p=0.014) and body mass index (OR 1.33 for each 5 kg/m2 increased, [1.05–1.68], p=0.017) were predictors of the PE. Hypertension was not significantly related to the PE (OR 1.55, [0.93–2.60], p=0.09)

Conclusion

In our group of patients with SARS-CoV-2, age, male sex, diabetes, lung disease and obesity were found to be independent predictors of the combined of all case death or need for orotracheal intubation within the first 30 days of infection symptoms. Larger studies are needed to confirm these results.

Funding Acknowledgement

Type of funding sources: None. Description of studied populationOdds-ratio and CI for the combined PE

Remote ischemic preconditioning ameliorates anthracycline-induced cardiotoxicity and preserves mitochondrial integrity: results from a randomized preclinical trial in pigs

Introduction

Anthracycline-induced cardiotoxicity (AIC) is a serious adverse effect occurring in a significant proportion of patients. Irreversible mitochondrial damage is a central mechanism of AIC. Despite many efforts, there is a lack of therapies able to prevent AIC. Remote ischemic preconditioning (RIPC) could be a promising therapy to prevent AIC due to the scheduled application of chemotherapy in cancer patients.

Purpose

To evaluate the cardioprotective efficacy of RIPC in large animal model of AIC.

Methods

Large-White pigs (n=20) underwent a validated protocol of AIC consisting on five intracoronary doxorubicin injections (0.45 mg/kg), on weeks 0, 2, 4, 6, 8 of the study. Pigs were randomized before the initiation of the study to remote ischemic pre-conditioning (RIPC, 3 cycles of 5 min lower limb ischemia followed by 5 min reperfusion) or sham procedure immediately before doxorubicin injections. An additional group of 10 pigs without any exposure to doxorubicin was carried out as controls. Pigs underwent a comprehensive serial cardiac magnetic resonance (CMR) exam baseline, and on weeks 6, 8, 12, and 16. After 16-week CMR, pigs were sacrificed and tissue samples collected. A second group of 10 pigs (randomized 1:1 for RIPC) underwent the same protocol but were sacrificed 2 weeks after the third doxorubicin dose for early evaluation of tissue changes. Primary endpoint of the study was CMR-based left ventricular ejection fraction on week 16.

Results

Until week 6 (time of fourth doxorubicin injection), LVEF remained unchanged in both groups. From there on, a progressive decline in LVEF was observed. LVEF depression trajectory was blunted in RIPC animals. Compared to controls, pigs undergoing RIPC before each doxorubicin dose had a significantly higher LVEF at week 16: median (IQR) 45% (27–50%) vs 33% (19–47%) in RIPC and controls respectively, p=0.04. Improvement in LVEF was mainly due to a more preserved contractile function, as evidence by smaller LVESV, and better regional contractile function. After 3 doxorubicin doses, a time where global (LVEF) and regional contractile function was still unchanged, transmission electron microscopy (TEM) showed fragmented mitochondria with remodeled cristae only in control pigs. At the end of the 16 weeks, TEM evaluation in control pigs (as compared to RIPC pigs) showed overt cardiomyocyte's mitochondrial fragmentation with overt structural derangement. At this time, RIPC pigs had significantly less interstitial fibrosis on histology.

Conclusions

In a translatable large animal model of AIC, RIPC applied immediately before each doxorubicin cycle resulted in a preservation of cardiac contractility with significantly higher long-term LVEF and less cardiac fibrosis. RIPC prevented the deleterious effects of doxorubicin on mitochondria since early stages of AIC. RIPC is a promising intervention to be tested in clinical trials to prevent cardiotoxicity.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovaciόn and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505)

New three-dimensional volumetric ultrasound probe for accurate quantification of atherosclerotic plaque volume

Background

Atherosclerosis burden is directly related with the development of clinical cardiovascular events. Recent ESC guidelines endorse carotid and/or femoral plaque burden assessment as a complement for conventional cardiovascular risk evaluation. Compared with previous 3D probes, new 3D-matrix transducers for vascular ultrasound imaging are designed to improve functionality and image quality for an accurate study of atherosclerosis burden.

Purpose

We aimed to validate a commercially available 3D-matrix transducer for plaque volume measurement in early disease stages (small plaques) when accurate plaque detection and quantification is challenging, and intermediate-advanced (medium-large size) plaques in carotid and femoral arteries.

Methods

We performed an ex vivo study using carotid and femoral arterial specimens from a pig model of early atherosclerosis in which actual 3D vascular ultrasound (3DVUS) volume measurements obtained using the new 3D-matrix transducer (XL14–3) were correlated against gold-standard histological measurements. Moreover, we performed a clinical experiment in a subset of intermediate-high risk patients from the “Athero-Brain: Head to Heart (H2H)” study with patent carotid and femoral atherosclerosis for comparing plaque volume evaluated by the new XL14–3 3D-matrix transducer, based on “electronic” 3D-sweep technology, with that measured by previously validated VL13–5 “mechanical” 3D-sweep transducer that uses a mechanically steered linear-array.

Results

In the ex vivo setting, we evaluated 11 atherosclerotic plaques (6 carotid and 5 femoral plaques, mean plaque volume 16.5±22.5 mm3 ranging in size from 1 to 56 mm3), finding a strong correlation between 3DVUS measures and the histological gold-standard with an intraclass correlation coefficient (ICC) of 0.994 (95% CI [0.976; 0.998]). In the clinical setting, we measured 25 plaques (14 carotid and 11 femoral plaques; mean plaque volume 273.4±216.5 mm3 ranging in size from 10 to 859 mm3) from 8 patients (mean age 75±5 years old, 45% men) finding again a strong correlation between 3DVUS electronic-based and mechanical-based volume measurements (ICC=0.996 95% CI [0.991; 0.998]). Correlation and Bland-Altman plots for the measurements of both experiments are displayed in the figure and showed good agreement (Slope close to 1 in the Passing Bablock analysis) with small or lower than clinically relevant differences between measurements.

Conclusions

3DVUS using new matrix technology accurately measures plaque volumes of early (small-size) to intermediate-advanced plaques located in superficial arteries like carotid and femoral arteries.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Carlos III Institute through an Integrated Excellence Project Grant

Beneficial effect of colchicine in an animal model of atherosclerosis

Background

Atherosclerosis is a chronic inflammatory disease and colchicine demonstrated clinical benefits in the treatment of stable coronary artery disease.

Purpose

Our aim was to assess the anti-inflammatory effects of colchicine on atherosclerotic vascular disease.

Methods

Atherosclerosis was induced in the abdominal aorta of 20 rabbits with high-cholesterol diet and balloon endothelial denudation. The study protocol lasted 36 weeks. After 18 weeks rabbits were randomized to receive either colchicine or placebo. Two animals died in each group. At randomization and at the end of the study, all animals underwent MRI and positron 18F-FDG PET/CT. In this post-hoc subgroup analyses, animals of each group in the first quartile of cholesterol levels were excluded. For MRI plaque volume values were expressed as Normalized Wall Index (NWI) and for 18F-FDG PET/CT values were expressed as mean maximum standard uptake (meanSUVmax). Statistical comparisons were made by using the Mann-Whitney U test for unpaired data and Wilcoxon signed-rank test for paired data.

Results

Results are summarized in Table 1. Animals with higher levels of cholesterol (6 per group) showed significant differences in favor to colchicine group, both as NWI at the end of the protocol 0.47 (IQR 0.05) in the colchicine group versus 0.52 (IQR 0.03) in the placebo; p=0.01] and as relative increase in meanSUVmax [−4.0% (IQR 30.1) in the colchicine group versus 35.1 (IQR 59.0) in the placebo; p 0.041] (Figure 1).

Conclusions

Colchicine may stabilize atherosclerotic plaque by reducing inflammatory activity and plaque burden.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): This work was supported by a grant from the Sociedad Española de Cardiología and a grant from the Carlos III Institute of Health of Spain and Fondo Europeo de Desarrollo Regional (FEDER, “Una manera de hacer Europa”)

Beta3-adrenergic stimulation restores endothelial mitochondrial dynamics and prevents pulmonary arterial hypertension

Background

Endothelial dysfunction is one of the most important hallmarks of pulmonary arterial hypertension (PAH). This leads to anomalous production of vasoactive mediators that are responsible for a higher vascular tone and a subsequent increase in pulmonary artery pressure (PAP), and to an increased vascular permeability that favors perivascular inflammation and remodeling, thus worsening the disease. Therefore, preservation of the endothelial barrier could become a relevant therapeutic strategy.

Purpose

In previous studies, others and we have suggested the pharmacological activation of the β3-adrenergic receptor (AR) as a potential therapeutic strategy for pulmonary hypertension (PH) due to left heart disease. However, its potential use in other forms of PH remain unclear. The aim of the present study was to elucidate whether the β3-AR agonist mirabegron could preserve pulmonary endothelium function and be a potential new therapy in PAH.

Methods

For this purpose, we have evaluated the effect of mirabegron (2 and 10 mg/kg·day) in different animal models, including the monocrotaline and the hypoxia-induced PAH models in rats and mice, respectively. Additionally, we have used a transgenic mouse model with endothelial overexpression of human β3-AR in a knockout background, and performed in vitro experiments with human pulmonary artery endothelial cells (HPAECs) for mechanistic experiments.

Results

Our results show a dose dependent effect of mirabegron in reducing mean PAP and Right Ventricular Systolic Pressure in both mice and rats. In addition, the use of transgenic mice has allowed us to determine that pulmonary endothelial cells are key mediators of the beneficial role of β3-AR pathway in ameliorating PAH. Mechanistically, we have shown in vitro that activation of β3-AR with mirabegron protects HPAECs from hypoxia-induced ROS production and mitochondrial fragmentation by restoring mitochondrial fission/fusion dynamics.

Conclusions

This protective effect of mirabegron would lead to endothelium integrity and preserved pulmonary endothelial function, which are necessary for a correct vasodilation, avoiding increased permeability and remodeling. Altogether, the current study demonstrates a beneficial effect of the β3-AR agonist mirabegron that could open new therapeutic avenues in PAH.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Programa de Atracciόn de Talento, Comunidad de Madrid

P3108Microcirculation injury is involved in anthracycline-induced cardiac toxicity

Background/Introduction

Cardiotoxicity (CT) is a major concern for cancer patients receiving anthracyclines. While the effect of anthracyclines on cardiomyocytes is well established, its impact on myocardial microcirculation has not been characterized.

Purpose

To evaluate the effect of low and high cumulative doses of doxorubicin (doxo) on anatomical and functional vasculature status evaluated by serial invasive Coronary Flow Reserve (CFR) and Cardiac Magnetic Resonance (CMR)-based quantitative perfusion in a large animal model.

Methods

Large-white male pigs (n=15, 30 kg) were distributed in 2 doxo regimes: Group 1) high cumulative dose (5 biweekly intracoronary (i.c) injections of 0.45 mg/kg of doxo) followed-up until week 16 (a time when severe left ventricular systolic dysfunction is present) and then sacrificed (N=5); Group 2) low cumulative dose of doxo (3 biweekly i.c. doses) followed-up until week 16 and then sacrificed (N=5)). Group 3) pigs sacrificed at 6 weeks (2 weeks after third doxo dose), N=5. Invasive catheter-based CFR was evaluated after i.c papaverine (0.5 mg/kg) while CMR quantitative rest perfusion maps were obtained after intravenous injection of gadolinium. CFR and CMR were performed before doxo, and at 0, 2, 4, 6 and 16 weeks thereafter. Cardiac vessels were evaluated ex vivo with trichrome staining. Statistical analysis was performed using one-way ANOVA with multiple pairwise comparisons (vs. baseline) and Bonferroni corrected p-value.

Results

CFR and CMR-quantitative myocardial perfusion were non-significantly reduced after 3 doxo doses despite myocardial vasculature was overtly injured on histology at this timepoint. Animals receiving 5 doxo doses suffered a progressive deterioration of CFR and CMR-perfusion until week 16 (1.41±0.23 vs 3.71±0.94 at baseline [p=0.014] and 65.4±18.2 ml/100g/min vs 154.9±56.3 ml/100g/min at baseline [p=0.046], respectively). At 16 weeks histology revealed extensive microvascular damage with media layer involvement and perivascular fibrosis. Pigs receiving 3 doxo doses showed less pronounced CFR reduction on long-term follow-up (3.13±0.82 vs 3.69±1.57 at baseline [p>0.05] but overt CMR-perfusion reduction (138.3±11.9 vs 197.8±37.1 at baseline [p=0.045]). On histology, damage of vasculature including arterioles was evidenced to a lesser extent than in the high cumulative doxo dose group with mild microvascular disruption and smooth muscle vacuolization.

Conclusions

Doxorubicin results in a progressive damage of the myocardial microcirculation. Even low cumulative doxo doses (resulting in no overt left ventricular dysfunction) results in vascular damage. The microcirculation status may serve as an early marker of doxorubicin cardiotoxicity.

3070Caloric restriction increases lifespan in dilated cardiomyopathy mice by enhancing mitochondrial quality control

Background/Introduction

Dilated cardiomyopathy (DCM) is a leading cause of heart failure (HF) in young and middle aged individuals worldwide. Alterations in mitochondrial dynamics (fusion/fission) and quality control (mitophagy) are critical for normal cardiac function. Imbalanced mitochondrial dynamics towards fission has been shown to contribute to DCM development in mice with ablation of the mitochondrial protease YME1L, which results in altered OPA1 processing precluding mitochondrial fusion. In these mice, the DCM phenotype includes a metabolic reprogramming of cardiomyocytes, shifting from fatty acid (FA) oxidation towards glucose. High fat diet (HFD) in these mice results in reversal of this metabolic reprogramming and rescue from DCM despite the genetic defect (lack of YME1) still present. These results opened a new venue for dietary approaches as a therapeutic strategy in HF. To understand whether the fat itself contained in the HFD was responsible of HF rescue, we studied the trajectories of cardiac function in mice with altered mitochondrial dynamics under HFD, caloric restriction and control chow.

Methods

Cardiomyocyte-specific Yme1l knock-out (cYKO) male mice (N=10–15) known to develop DCM phenotype at 20–25 weeks of age were randomized to 3 different diets (1: HFD containing >30% crude fat; 2: non-fat diet containing <0.5% crude fat, and 3: control diet containing 10% crude fat) at 10 weeks of age. Every 10 weeks, cardiac function was tested by echocardiography. At 30 weeks, animals underwent a multitracer microPET/CT (glucose and FA uptake) to evaluate myocardial substrate utilization. At the end of the study, animals were sacrificed and hearts were harvested for histological and further tissue analyses.

Results

As expected, HFD was associated with a better left ventricular ejection fraction (LVEF; %) at 30 weeks: 37.97±8.59 vs. 29.16±8.9 in control diet, p=0.04. This functional improvement was associated with an increase in FA uptake on microPET/CT. Non-fat diet was associated with even higher LVEF at 30 weeks: 44.94±11 vs. 29.16±8.9 in control diet, p=0.0001, as well as smaller LV diameter (mm): 3.58±0.29 vs. 4.3±0.39 in control diet, p<0.0001 (A). Lifespan of mice on non-fat diet was significantly prolonged (70% extension compared to control) (B). Enhanced mitochondrial clearance (mitophagy) mediated by Parkin, together with an increase in autophagy related protein as LC3B was identified in the non-fat diet group (C).

Conclusion

Different dietary approaches have been shown to be beneficial in the prevention of DCM in mice with altered mitochondrial dynamics. Caloric restriction (non-fat diet) is able to prevent DCM, reverse metabolic reprogramming, increase mitochondrial quality control and ultimately prolong lifespan in mice with genetic defect associated with altered mitochondrial dynamics. Interventions aiming at enhancing cardiac mitophagy might represent a new therapeutic option in DCM.

P5999Heart failure rescue by high fat diet in a porcine model of hibernated myocardium

Background

Extensive coronary artery disease without revascularization options results in ischemic hibernated myocardium and ultimately heart failure (HF). A metabolic reprogramming of the heart characterized by a shift from fatty acids (FFA) to glucose as the preferential metabolic substrate is frequent in HF and hibernated myocardium. Previous studies in mouse models of HF have shown that high fat diet (HFD) is able to reverse the metabolic reprogramming of the heart and improve cardiac function. Here we used a translational large animal model of ischemic HF evaluated by state-of-the-art imaging modalities

Methods

IHM was generated in Yucatan minipigs (N=50) by progressive stenosis of the proximal left anterior descending (LAD) after surgical insertion of a casein ameroid around the artery. Pigs underwent a serial multimodality imaging study including magnetic resonance imaging (MRI), multi-tracer PET/CT (18FDG & 14(R,S)-[18F]Fluoro-6-thia-heptadecanoic acid (18F-FTHA) 19F-palmitate in-house synthetized), and invasive coronary angiography (ICA). Once hibernated myocardium with metabolic switch was documented (complete occlusion of LAD, LVEF<50% on MRI, viable myocardium with dobutamine/MRI- evaluated contractile reserve, and metabolic substrate utilization shift towards glucose on PET/CT), animals were randomized to HFD or regular diet for 3 months

Results

The first part of the study was dedicated to establish the model in 42 pigs. Pigs were followed-up for 170±24 days with monthly ICA, MRI and PET/CT. Severe LAD stenosis was documented in all pigs 3–4 weeks after surgery. Mortality during follow-up was 57% (n=24) (15 peri-procedure, 2 between day 1 and 7, seven between day 7 and 45). Among those surviving beyond the sixth week, 90% (16/18) developed hibernated myocardium (mean LVEF 36±10%, absence of transmural delayed enhancement, contractile reserve and metabolic switch on PET/CT).

In the second part of the study, 5 long-term survivors were allocated to receive HFD (20% extra lard), while 3 pigs served as controls. Mean LVEF before HFD initiation was 35±8%, and 36±5% in controls. Three months HFD was associated with a LVEF improvement in all treated animals (mean LVEF at the end of follow-up was 45±9%). Control animals on regular diet did not show any change in LVEF (35±5% at the end of follow-up)

Conclusions

We present a large animal model of HF due hibernated myocardium by placing an ameroid around the LAD. Mortality of this model is high (approx. 55%) but long-term survivors resemble all features seen in patients: LAD progressive stenosis with final occlusion but viable myocardium, LVEF deterioration and metabolic switch

Feeding pigs with HFD to force cardiac reutilization of FFA, results in a consistent and large LVEF improvement in all animals

Cardiac metabolic switch might be implicated in the pathogenesis of systolic dysfunction in hibernated myocardium and is a potential target for nutritional approaches

P4684Differential right ventricular adaptation patterns to chronic pressure overload

Background

Right ventricular (RV) dysfunction is the most important prognostic factor in chronic pulmonary hypertension (PH), but its underlying mechanisms are unknown. Clinical observation and prior experimental work suggest that RV pressure overload is not the only cause since the degree of RV adaptation varies with similar RV end-systolic pressures.

Purpose

Our aim was to characterize serial RV adaptation by cardiac magnetic resonance (CMR) in 3 different experimental large-animal models of increased afterload: a model of chronic postcapillary PH, a model of PH secondary to systemic-to-pulmonary shunt and a model of mechanical RV pressure overload (generated by pulmonary artery [PA] banding).

Methods

Four-week old piglets underwent pulmonary vein banding surgery to generate the chronic postcapillary PH model (n=20), aorto-pulmonary shunt (n=6), PA banding (n=7) or sham operation (n=7). They were followed up monthly with CMR and right heart catheterization (RHC). All procedures followed the “Principles of laboratory animal care”. Comparison of continuous variables among groups was performed with Mann-Whitney U test.

Results

Animals with either postcapillary PH or PH secondary to aorto-pulmonary shunt presented significant RV dilatation, hypertrophy and dysfunction that was maintained during follow-up (median RV end-systolic volume [RVESV]=32.6 ml/m2 for postcapillary PH and 32.6 ml/m2 for shunt vs. 16.1 ml/m2 in sham controls; median RV ejection fraction [RVEF]=61.5% for postcapillary PH and 60.5% for shunt vs. 69.6% in sham controls at the end of follow-up). Animals with PA banding also presented with significant RV dilatation and hypertrophy at the first month follow-up, but unlike all other groups, they developed reverse RV remodeling from the second month onwards and maintained normal RV volumes and RVEF values until the end of follow-up despite having severe RV hypertrophy (RV mass 22.6 g/m2 in PA banding vs. 16.1 g/m2 in controls at the 4th month follow-up; Figure).

CMR parameters (median values).

Conclusion

In PH there is a maladaptive RV hypertrophy that is not present in a model of progressive RV pressure overload without alterations of the pulmonary circulation. Increased RV pressure overload alone does not fully explain PH-associated RV dysfunction. Further research is needed to clarify the underlying mechanisms of adaptive and maladaptive hypertrophy in PH.

Acknowledgement/Funding

The CNIC is supported by the Ministerio de Ciencia, Innovaciόn y Universidades and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence

P6423Cardioprotective effect of metoprolol in myocardial ischemic/reperfusion injury: the role of total ischemic time

Background

Metoprolol administration before reperfusion has shown relevant cardioprotective effect in the AMI in preclinical setting. However, the translation to clinical arena has controversial results. The time at drug administration in the context of total duration of ischemia have been pointed as fundamental aspects to be studied.

Purpose

evaluate the cardioprotective effect of metoprolol administration regarding to the total time of ischemia, using a swine model of reperfused AMI.

Methods

50 pigs were subjected to 3 temporary protocols of left anterior descending (LAD) coronary artery occlusion followed by reperfusion. 30 pigs undergoing 40 minutes of ischemia (T40) were randomized 2:1 to intravenous placebo or metoprolol administrated 20 minutes after LAD occlusion.10 pigs undergoing 20 minutes of ischemia 20 (T20) and 10 pig undergoing 60 minutes of ischemia 60 (T60) were randomized 1:1 to intravenous placebo or metoprolol. Before reperfusion a CT study was performed to stablish the area at risk (AAR). CMR was performed at 7 and 45 days after AMI.

Results

48 subjects comprised the 7-day CMR follow-up (1 dead in the metoprolol T40,1 dead in the placebo T40) while 41 subjects comprised the 45-day CMR follow-up (5 deceases in the placebo T40 group, and 2 in the placebo T60 group). AAR was similar among groups (Table 1, Panel B). At 7-day follow-up, IS washigher in the placebo groups as compared to the metoprolol groups, but only reach significant difference in the T40 (29,67% vs. 22,85%, p=0.04, Table 1, Panel A). LVEF measured at 45-day follow-up was higher in the metoprolol groups vs the control groups, but the differences were statistically significance in the T40 (32,76% vs 39,68% p=0.04, Panel C).

Table 1 20 mins. Ischemia (T20) 40 mins. Ischemia (T40) 60 mins. Ischemia (T60) P PLACEBO METOPROL P value PLACEBO METOPROL P value PLACEBO METOPROL P value AAR 32 (28.14–37.89) 33.41 (28.12–38.32) 0.82 32.99 (29.25–35.83) 31.42 (26.94–37.83) 0.72 33.28 (29.68–41.14) 33.93 (28.17–40.69) 0.80 0.98 IS 1.96 (0.92–3.61) 0 (0–0.65) 0.063 29.67 (27.23–35.35) 22.85 (14.53–28.10) 0.042 36.21 (33.55–40.91) 33.78 (39.36–35.39) 0.31 <0.001 LVEF 54.36 (49.75–58.97) 55.34 (53.14–60.88) 0.66 32.76 (26.91–36.10) 39.68 (35.45–45.28) 0.023 26.13 (22.40–31.25) 32.99 (31.32–35.19) 0.071 <0.001 Values are median (interquartile range). Bold indicates statistical significance. AAR = Area at Risk (% of Left ventricular). IS = Infartc Size (% of Left ventricular). LVEF = Left ventricular ejection fraction (%).

Conclusions

Metoprolol administrated early before reperfusion reduced IS and improved medium-term LVEF compared to placebo. But only T40 receiving metoprolol shownsignificant protection vs placebo. These findings suggest a relevant effect of metoprolol ischemic/reperfusion injury, but depending on the total ischemic time, establishing a potential temporary cardioprotection opportunity window.

P596Early markers of right ventricular involvement in experimental chronic postcapillary pulmonary hypertension

Background

In chronic pulmonary hypertension (PH), the main cause of death is right ventricular (RV) failure. However, the onset of RV dysfunction varies significantly among patients. Early recognition of RV maladaptation would be highly relevant.

Purpose

To identify cardiac magnetic resonance (CMR)-derived parameters affected in early stages of PH before the development of RV dysfunction.

Methods

Experimental chronic PH was generated by pulmonary vein banding in 76 pigs whereas 14 animals underwent sham operation. Animals were followed-up monthly with right heart catheterization (RHC) and immediate CMR for a maximum of 9 months. CMR exams included a T1-mapping sequence to quantify equilibrium-extracellular volume (ECV) at the RV insertion points. Pairs of RHC and CMR examinations were compared among controls and PH with normal RV ejection fraction (RVEF≥55%) or reduced (REVF<55%) using ANCOVA test with Bonferroni correction. All procedures followed the “Principles of laboratory animal care”.

Results

In the presence of PH confirmed by RHC and normal RVEF, the RV displays significant hypertrophy and increased myocardial native T1 and ECV, despite preserved ventricular dimensions and PA flow (Fig 1B). In advanced stages of the disease, RV-AP uncoupling and reduced PA pulsatility develop together with RV dilatation and failure (Fig 1C).

CMR parameters in sham and PH animals Sham controls (n=25 evaluations) PH with normal RVEF (n=155 evaluations) PH with low RVEF (n=70) RVEF (%) 62±5 61±4 47±8# RVEDV (mL/m2) 73±18 83±17 111±29# RVESV (mL/m2) 28±8 32±8 61±25# RV mass (g/m2) 17±4 23±5* 30±11# PA area (cm2/m2) 5.5±1.2 6.3±1.6 8.7±2.2# Native T1 anterior RVIP (ms) 983±75 1043±78* 1055±90# ECV anterior RVIP (%) 27±5 31±6* 36±7# Native T1 inferior RVIP (ms) 959±68 1022±71* 1032±99# ECV inferior RVIP (%) 25±5 31±6* 36±7# PA pulsatility (%) 29±6 27±7 21±3# Ea/Emax 40±16 47±11 97±65# RVEDV: RV end-diastolic volume; RVESV: RV end-systolic volume; RVIP: RV insertion point. *p<0.05 1 vs. 2; #1 vs. 3.

NativeT1: control, PH-normal RV, RV dysf

Conclusion

RV hypertrophy and ECV expansion are early mechanisms in RV adaptation to postcapillary PH, whereas ventricular and PA dilatation, RV-PA uncoupling and reduced pulsatility appear in more advanced stages concurring with systolic dysfunction.

Acknowledgement/Funding

The CNIC is supported by the Ministerio de Ciencia, Innovaciόn y Universidades and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence

[A comparative study of three systems for quantifying the spike and wave index in patients with continuous spikes and waves during slow sleep]

INTRODUCTION

Continuous spikes and waves during slow sleep (CSWS) is an epileptic encephalopathy of childhood with a pattern of epileptiform discharges during sleep, which, if prolonged over time, produce severe neuropsychological impairment. Quantification of the paroxysms by means of a spike and wave index (SWI) > 85% establishes a presumptive diagnosis and allows early therapy to be started to prevent such impairment.

AIMS

To compare the results of the classic method for calculating the SWI against two proposals that optimise the relation between the analysis time employed and the diagnostic sensitivity.

PATIENTS AND METHODS

The nocturnal electroencephalographic registers of 17 patients with CSWS were studied. Two observers calculated the SWI with the classic method, as well as with two other methods, M2 and M3, first in the active phase and then in the remission phase. The time required by each method, the individual SWI values and the agreement between methods and observers were compared.

RESULTS

With M3 two of the patients failed to reach the cut-off point of SWI > 85%. Agreement in the active phase of CSWS after M2 and M3 was 0.762 and 0.704, respectively, while in the remission phase it was 0.951 and 0.830. Inter-observer agreement exceeded 0.905 in all cases.

CONCLUSIONS

The two abbreviated methods can be used in both the active and the remission phases, with a substantial reduction in the analysis time that is needed. Our results support the current tendency to consider SWI > 60% as suggestive of CSWS. Method M2 yields results that are closer to those of the classic method than those of M3.

Erratum:Quality of life in long-term premenopausal early-stage breast cancer survivors from Spain. Effects of surgery and time since surgery

In this article published in Volume 21, issue 5, the authors' names were incorrectly stated in the Pubmed abstract as: "Ignacio Arraras J(1), Juan Illarramendi J, de la Cruz S, Asin G, Manterola A, Ibanez B, Salgado E, Cambra K, Zarandona U, Angel Dominguez M, Vera R.". The correct authors' names are: "Arraras JI(1), Illarramendi JJ, de la Cruz S, Asin G, Manterola A, Ibanez B, Salgado E, Cambra K, Zarandona U, Dominguez MA, Vera R.". This error appeared only in the PubMed database and not in the print form of the Journal.

Ovariectomy increases vascular calcification via the OPG/RANKL cytokine signalling pathway

BACKGROUND

Observational studies suggest a strong relationship between menopause and vascular calcification. Receptor activator of nuclear factor-kappaBeta ligand (RANKL) and osteoprotegerin (OPG) are critical regulators of bone remodelling and modulate vascular calcification. We assessed the hypothesis that ovariectomy increases vascular calcification via the OPG/RANKL axis.

MATERIALS AND METHODS

Age-matched sexually mature rabbits were randomized to ovariectomy (OVX, n = 12) or sham procedure (SHAM, n = 12). One month post-procedure, atherosclerosis was induced by 15 months 0.2%-cholesterol diet and endothelial balloon denudations (at months 1 and 3). Aortic atherosclerosis was assessed in vivo by magnetic resonance imaging (MRI) at months 9 and 15. At sacrifice, aortas were harvested for ex vivo microcomputed tomography (microCT) and molecular analysis of the vascular tissue.

RESULTS

Vascular calcification density and calcific particle number were significantly greater in OVX than SHAM (8.4 +/- 2.8 vs. 1.9 +/- 0.6 mg cm(-3), P = 0.042, and 94 +/- 26 vs. 33 +/- 7 particles cm(-3), P = 0.046, respectively). Calcification morphology, as assessed by the arc angle subtended by the largest calcific particle, showed no difference between groups (OVX 33 +/- 7 degrees vs. SHAM 33 +/- 5 degrees , P = 0.99). By Western blot analysis, OVX increased the vascular OPG:RANKL ratio by 66%, P = 0.029, primarily by decreasing RANKL (P = 0.019). At month 9, MRI demonstrated no difference in atheroma volume between OVX and SHAM, and no significant change was seen by the end of the study.

CONCLUSIONS

In contrast to bone, vascular OPG:RANKL ratio increased in response to ovariectomy with a corresponding fourfold increase in arterial calcification. This diametrical organ-specific response may explain the comorbid association of osteoporosis with calcifying atherosclerosis in post-menopausal women.

Plaque progression and regression in atherothrombosis

Atherosclerotic disease is a pathological process characterized by the deposition of lipid and other blood-borne material within the arterial wall. The deposition of these materials and the subsequent thickening of the wall may significantly compromise the vessel lumen. Atherosclerosis is a diffuse disease with focal clinical manifestations that are the consequence of thrombotic complications on disrupted atherosclerotic lesions. Until recently, atherosclerosis development was envisaged as an incessant progressing process; however, new evidence has shown that atherosclerotic plaque homeostasis is not necessarily a constantly progressing process. There are many data showing that atherosclerotic plaque formation can be slowed, stopped or even reversed. Comprehension of the underlying mechanisms involved in the homeostasis of atherosclerotic plaque (progression/regression) should allow the development of interventions enhancing the regression pathway. Novel imaging technology has allowed the accurate evaluation of plaque progression, vital in the assessment of the efficacy of interventions. In this review we discuss the processes involved in the formation and progression of atherosclerotic lesions, the triggers for plaque disruption, as well as new therapies. We also deal with the potential pathways of plaque regression, as well as tools for accurate serial atherosclerotic quantification.

A novel anti-ischemic nitric oxide donor (LA419) reduces thrombogenesis in healthy human subjects

BACKGROUND

Platelet and endothelial production of nitric oxide (NO) is known to be impaired in coronary artery disease patients. Compounds that release NO (e.g. nitrates) have antiplatelet effects, but at supratherapeutic doses with hypotensive side effects.

OBJECTIVES

To investigate the antithrombotic effect on human blood of a novel NO donor (LA419) with known anti-ischemic properties but without hypotensive side effects and to compare with abciximab.

PATIENTS/METHODS

Healthy subjects (n = 8; 32 +/- 3 years) received daily aspirin starting three days prior to the study day. Treatments (LA419 10 and 20 microm, and abciximab 4 microm) were added ex vivo to non-anticoagulated blood, and the antithrombotic properties were assessed by measuring changes in thrombus size from pretreatment baseline in the Badimon perfusion chamber at low and high shear rates. Platelet surface adhesion using a Cone and Platelet Analyzer (CPA) and platelet fibrinogen-receptor activation with flow cytometry were also evaluated.

RESULTS

At low shear rates, LA419 displayed a reduction in thrombus area of 43% +/- 8% (10 microm) and 56% +/- 6% (20 microm), whereas at high shear rates the reductions were 44% +/- 3% (10 microm) and 62% +/- 6% (20 microm). Platelet surface adhesion with the CPA was also reduced. Abciximab exhibited a strong inhibitory effect on thrombus formation, platelet surface adhesion and fibrinogen receptor activation.

CONCLUSIONS

The novel NO donor, LA419, shows a strong antithrombotic effect in human blood, which is comparable to abciximab, especially under high shear rate conditions. Our observations suggest that the availability of an NO donor could prove beneficial in the prevention of thrombotic complications of cardiovascular disease. Further clinical studies are warranted.