Association of hydroxytyrosol enriched olive oil with vascular function in chronic coronary disease

BACKGROUND

Hydroxytyrosol reduces low-density lipoprotein oxidation, contributing to prevention of atherosclerosis progression.

METHODS

In a prospective, crossover, double-blind, placebo-controlled trial, 30 chronic coronary artery syndrome (CCAS) patients were randomized to 4 capsules/day, containing 412.5 mg olive oil with 2.5 mg hydroxytyrosol (OOHT) each one or placebo for 1 month and then were crossed over to the alternate treatment (placebo or OOHT). We measured (a) perfused boundary region (PBR) of the sublingual arterial microvessels (increased PBR indicates reduced glycocalyx thickness), (b) flow-mediated dilation (FMD), (c) Coronary Flow Reserve (CFR) and markers of LV diastolic function by Doppler echocardiography, (d) pulse wave velocity (PWV), and (e) oxidative stress, inflammatory biomarkers and blood lipids at baseline and after treatment.

RESULTS

Treatment with OOHT improved PBR, FMD, CFR and PWV compared to baseline (1.8 ± .3 vs. 1.7 ± .4 μm, p = .040, 3.7 ± 2.1 vs. 6.5% ± 2.3%, p < .001, 2.3 ± .4 vs. 2.5 ± .4, p = .030 and 11.1 ± 1.8 vs. 11.8 ± 2.3 m/s, p = .002) while there was no effect after placebo (p = NS). No effect of OOHT treatment was observed on blood pressure. There was a parallel improvement of E' of the mitral annulus and deceleration time of the E wave of mitral inflow after OOHT (p < .05) but not after placebo. Compared to baseline, treatment with OOHT reduced malondialdehyde, a marker of lipid peroxidation, oxidized LDL, triglycerides, PCSK9 and CRP blood levels (p < .05) in contrast to placebo.

CONCLUSIONS

Hydroxytyrosol-enriched olive oil may have beneficial effects on endothelial, arterial and LV diastolic function likely by reducing oxidative and inflammatory burden in CCAS, though further studies are needed to confirm this mechanism.

Myocardial Protection and Current Cancer Therapy: Two Opposite Targets with Inevitable Cost

Myocardial protection against ischemia/reperfusion injury (IRI) is mediated by various ligands, activating different cellular signaling cascades. These include classical cytosolic mediators such as cyclic-GMP (c-GMP), various kinases such as Phosphatydilinositol-3- (PI3K), Protein Kinase B (Akt), Mitogen-Activated-Protein- (MAPK) and AMP-activated (AMPK) kinases, transcription factors such as signal transducer and activator of transcription 3 (STAT3) and bioactive molecules such as vascular endothelial growth factor (VEGF). Most of the aforementioned signaling molecules constitute targets of anticancer therapy; as they are also involved in carcinogenesis, most of the current anti-neoplastic drugs lead to concomitant weakening or even complete abrogation of myocardial cell tolerance to ischemic or oxidative stress. Furthermore, many anti-neoplastic drugs may directly induce cardiotoxicity via their pharmacological effects, or indirectly via their cardiovascular side effects. The combination of direct drug cardiotoxicity, indirect cardiovascular side effects and neutralization of the cardioprotective defense mechanisms of the heart by prolonged cancer treatment may induce long-term ventricular dysfunction, or even clinically manifested heart failure. We present a narrative review of three therapeutic interventions, namely VEGF, proteasome and Immune Checkpoint inhibitors, having opposing effects on the same intracellular signal cascades thereby affecting the heart. Moreover, we herein comment on the current guidelines for managing cardiotoxicity in the clinical setting and on the role of cardiovascular confounders in cardiotoxicity.

Empagliflozin rescues primary murine cardiac fibroblasts, but not cardiomyocytes, from hypoxia-reoxygenation injury through STAT3-mediated cascades

Introduction

Empagliflozin (EMPA) is a selective sodium glucose co-transporter 2 inhibitor (SGLT2i) and an established drug against type 2 diabetes mellitus. Cardiovascular clinical outcome trials on EMPA have shown a reduced mortality rate related to major cardiovascular events, but the precise mechanism of action remains elusive. We have previously proved that chronic EMPA administration reduces infarct size in an in vivo murine model of ischemia / reperfusion injury, irrespective of the diabetic status. The cardioprotective effect of EMPA was attributed to the increase of Signal Transducer and Activator of Transcription 3 (STAT3) phosphorylation.

Purpose

In this study we aimed to decipher the cell specific effects of EMPA on primary adult ventricular murine cardiomyocytes (pAVMCs) and primary murine cardiac fibroblasts (pMCFs), subjected to hypoxia/reoxygenation (HYP/REO) and to 1) investigate the effect of EMPA on cell death, and 2) reveal the mechanism of cardioprotection.

Methods

PAVMCs and pMCFs were isolated from adult C57BL/6 murine hearts (n=4–6) and were incubated with EMPA (500nM–100nM) for 24 hours. Cells were then subjected to 3 hours of HYP (99% N2), followed by 1 hour of REO. STATTIC, a selective STAT3 inhibitor was used (500nM–1μM) to determine the contribution of STAT3 on the observed effect. MTT assay was performed at the end of REO to determine cell viability. To unravel the mechanism of cardioprotection, the experimental protocol was repeated, and the cells were either stained with dihydroethidium (DHE) dye to determine relative oxidative stress changes or were harvested for isolation of total protein content. We focused on STAT3 and Akt kinase as key mediators of the cardioprotective survivor activating factor enhancement (SAFE) and the reperfusion injury salvage kinase (RISK) pathways. We also investigated the expression of Cardiotrophin-1 (CT-1), as a potential upstream mediator of STAT3 phosphorylation.

Results

The evaluation of cell death revealed that pMCFs viability was significantly increased upon EMPA treatment. Added to this, STATTIC co-treatment with EMPA blunted the protective effect on pMCFs, which indicates that EMPA's protection is STAT3-mediated. Oxidative stress remained unaltered by the treatments. Investigation of the molecular pathways that are responsible for the increased viability of pMCFs revealed that EMPA treatment induces an increased phosphorylation of STAT3 and an increase in CT-1 expression, which are both reversed by STATTIC. Akt phosphorylation and expression remained unchanged by EMPA treatment. Notably, the effect of EMPA on pAVMCs' viability was negligible.

Conclusion(s)

EMPA does not protect pAVMCs, from HYP/REO injury. EMPA rescues the pMCFs in a STAT-3 dependent manner which indicates that EMPA's cardioprotective effect is cell specific and implicates the SAFE pathway.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boehringer Ingelheim International GmbHGrant title: “Investigation of the distinct effects of Empagliflozin on different cell populations of the healthy myocardium”

The prognostic significance of the echocardiographic evaluation of left ventricular myocardial deformation indices at peak cardiopulmonary exercise in patients with severe dilated cardiomyopathy

Background

Cardiopulmonary exercise testing (CPET) integrally estimates exercise capacity (peak VO2) and cardiovascular (CV) prognosis (VE/VCO2 slope) in patients with dilated cardiomyopathy (DCM). Myocardial deformation indices (MDI), measured by speckle tracking imaging (STI), allow reliable measurements of left ventricular (LV) function. Little is known about the exercise-induced changes of the multidimensional mechanical properties of the heart and their impact in patient's survival. We aimed to investigate the predictive role regarding 3-year survival of LV MDI (at rest and peak exercise) as well as the main CPET parameters (peak VO2, VE/VCO2 slope) in DCM patients with reduced ejection fraction (EF) using as primary combined end-point the heart transplantation and all cause death.

Patients and methods

We evaluated LV function using STI at rest and at peak exercise during the same CPET session in 53 DCM patients (54±12 years, 76% males, ejection fraction 33±9%).We measured global longitudinal strain (GLS), longitudinal strain rate at systole (LSRS) and diastole (LSRD) at baseline and at peak CPET along with CPET parameters. After a period of 38±15 months, all DCM patients were evaluated by a telephone interview.

Results

From the whole population, totally 7 patients (13%) reached the primary end-point (Group A) as 2 patients were submitted to heart transplantation and 5 patients died (60±13 years, 86% males, EF = 28±9%) while 46 patients remained alive at 3-year follow-up (Group B, 53±12 years, 74% males, EF = 33±9%). We found that Group A patients had similar age, sex and EF but reduced peak VO2 (p=0.04) and increased VE/VCO2 slope (p=0.004), impaired GLS at baseline and peak exercise (p=0.02 and p=0.04, respectively) as well as LSRS at peak exercise (p=0.05) compared to Group B patients.

Conclusions

The evaluation of GLS (rest and peak exercise) and LSRS (peak exercise) as systolic indices of LV myocardial deformation adds valuable information regarding CV prognosis in patients with severe idiopathic DCM. A combined baseline work-up protocol consisted of MDI evaluation at rest and exercise plus the CPET indices may characterize the true severity of heart failure in a DCM population.

Funding Acknowledgement

Type of funding sources: None.

Cardioprotection by selective SGLT2 inhibitors in a non-diabetic mouse model of myocardial ischemia/reperfusion injury: a class or a drug effect?

Background

Empagliflozin (EMPA), Dapagliflozin (DAPA) and Ertugliflozin (ERTU) are selective sodium glucose co-transporter 2 inhibitors (SGLT2i) acting against type 2 diabetes mellitus.

Purpose

Due to differences in clinical trial outcomes, we aimed to 1) compare the cardioprotective effects of selective SGLT2i in terms of infarct size (IS) reduction and 2) reveal the mechanism of cardioprotection in non-diabetic mice.

Methods

C57BL/6 mice were randomized and orally received EMPA (10mg/kg/day), DAPA (9.0mg/kg/day), ERTU (9.7mg/kg/day) or vehicle for 7 days. IS was measured after 30' ischemia (I), and 120' reperfusion (R). EMPA, DAPA and ERTU were given at equivalent stoichiometrically doses (ESD). Body weight and fasting blood glucose (FBG) levels were determined at baseline and at the end of the treatment. On the 7th day, mice were housed in metabolic cages for 24 hours. Urine volume (UV), food and water uptake and 24h-glucose levels were determined to examine the extend of SGLT-2 inhibition by the drugs. In a second series, the ischemic myocardium was taken (10'R), shotgun proteomics were performed and several cardioprotective pathways were evaluated. In a third series, the dominant pathways were evaluated through molecular analyses and mitochondrial functionality. The causal relationships in the mechanism of protection, was established by inhibiting the concomitant cardioprotective pathways. Static, the specific STAT-3 inhibitor and wortmannin (a PI3K inhibitor) were administered and IS was measured upon 30'I/120' R.

Results

EMPA and DAPA but not ERTU reduced IS at this dose. Body weight and FBG levels were not affected by the treatments. EMPA, DAPA and ERTU lead to significant increase in UV and urinary glucose levels compared to the control group independently of the water and food intake. There was no significant difference in the parameters among the different SGLT-2i indicating that the chosen doses are sufficient to produce the same pharmacological SGLT-2 inhibition in mice. Proteomics revealed mitochondrial metabolism and NF-kB signaling as significant. Only EMPA preserved mitochondrial functionality in complex I & II linked oxidative phosphorylation. NF-kB, RISK and STAT-3 activation and the downstream reduction in apoptosis were evident in EMPA and DAPA groups coinciding with IS reduction. Static and wortmannin significantly attenuated IS reduction both in EMPA and DAPA groups indicating that STAT-3 and PI3K activation are the leading mechanisms of cardioprotection. Among several upstream mediators, fibroblast growth factor 2 (FGF-2) and caveolin-3 were increased in EMPA and DAPA groups.

Conclusions

Short term EMPA, DAPA and ERTU at the chosen ESD inhibit SGLT-2i in a similar extent but only EMPA and DAPA reduce IS. Our study reveals drug specific effects on cardioprotection against I/R injury. Cardioprotection afforded by EMPA and DAPA are STAT-3 and PI3K dependent and associated with increased FGF-2 and Cav-3 expression.

Funding Acknowledgement

Type of funding sources: None.

Cardioprotection by selective SGLT-2 inhibitors in a non-diabetic mouse model of myocardial ischemia/reperfusion injury: a class or a drug effect?

Major clinical trials with sodium glucose co-transporter-2 inhibitors (SGLT-2i) exhibit protective effects against heart failure events, whereas inconsistencies regarding the cardiovascular death outcomes are observed. Therefore, we aimed to compare the selective SGLT-2i empagliflozin (EMPA), dapagliflozin (DAPA) and ertugliflozin (ERTU) in terms of infarct size (IS) reduction and to reveal the cardioprotective mechanism in healthy non-diabetic mice. C57BL/6 mice randomly received vehicle, EMPA (10 mg/kg/day) and DAPA or ERTU orally at the stoichiometrically equivalent dose (SED) for 7 days. 24 h-glucose urinary excretion was determined to verify SGLT-2 inhibition. IS of the region at risk was measured after 30 min ischemia (I), and 120 min reperfusion (R). In a second series, the ischemic myocardium was collected (10th min of R) for shotgun proteomics and evaluation of the cardioprotective signaling. In a third series, we evaluated the oxidative phosphorylation capacity (OXPHOS) and the mitochondrial fatty acid oxidation capacity by measuring the respiratory rates. Finally, Stattic, the STAT-3 inhibitor and wortmannin were administered in both EMPA and DAPA groups to establish causal relationships in the mechanism of protection. EMPA, DAPA and ERTU at the SED led to similar SGLT-2 inhibition as inferred by the significant increase in glucose excretion. EMPA and DAPA but not ERTU reduced IS. EMPA preserved mitochondrial functionality in complex I&II linked oxidative phosphorylation. EMPA and DAPA treatment led to NF-kB, RISK, STAT-3 activation and the downstream apoptosis reduction coinciding with IS reduction. Stattic and wortmannin attenuated the cardioprotection afforded by EMPA and DAPA. Among several upstream mediators, fibroblast growth factor-2 (FGF-2) and caveolin-3 were increased by EMPA and DAPA treatment. ERTU reduced IS only when given at the double dose of the SED (20 mg/kg/day). Short-term EMPA and DAPA, but not ERTU administration at the SED reduce IS in healthy non-diabetic mice. Cardioprotection is not correlated to SGLT-2 inhibition, is STAT-3 and PI3K dependent and associated with increased FGF-2 and Cav-3 expression.

Comparative study on the cardioprotective effects against ischemia/reperfusion injury of the selective SGLT2 inhibitors, empagliflozin, dapagliflozin and ertugliflozin in non-diabetic mice

Background/Introduction

The sodium glucose co-transporter 2 selective inhibitors (SGLT2i) empagliflozin (EMPA), dapagliflozin (DAPA) and ertugliflozin (ERTU) are established drugs against type 2 diabetes mellitus (T2DM). However, the clinical outcomes among them differ; EMPA and DAPA treatment significantly reduced the frequency of cardiovascular events, while ERTU did not reach this endpoint. Thus, the comparative cardioprotective properties and further mechanistic insights for each SGLT2i should be elucidated.

Purpose

We have previously proved that chronic EMPA administration reduces infarct size (IS), independently of the presence of T2DM in vivo. We aimed to 1) investigate the comparative cardioprotective effect of EMPA, DAPA and ERTU in terms of IS reduction upon short term administration and 2) reveal the mechanisms of cardioprotection in non-diabetic mice.

Methods

Adult C57BL/6 mice were randomized into four groups and orally received EMPA (10mg/kg/day), DAPA (9.0mg/kg/day), ERTU (9.7mg/kg/day) or vehicle (5% DMSO in water for injection) for 7 days. The doses of DAPA and ERTU were stoichiometrically equivalent to EMPA's dose that we have previously used as clinically relevant. On the 8th day, mice were subjected to 30' ischemia (I), following by 2h reperfusion (R) and IS was measured. Body weight and fasting blood glucose levels were determined at baseline and at the end of the treatment. Then, we sought to unveil the mechanistic differences among those drugs which are responsible for the observed cardioprotection. Additional mice were randomized into the four groups and were treated for 7 days, as described above. On the 8th day, mice were subjected to 30'I/10'R and the ischemic myocardium was collected. We focused on the cardioprotective signaling of SAFE and RISK pathways and we evaluated the phosphorylation and expression of STAT3, PI3K, Akt and eNOS. Also, we examined the gene expression levels of IL-6 and TGF-β as possible mediators of the SAFE pathway.

Results

Short term oral administration of EMPA and DAPA reduced myocardial IS (19.6%±2.6 EMPA, 18.0%±3.3 DAPA vs. 35.3%±1.7 Control, p&lt;0.01). On the contrary, administration of ERTU did not reduce IS (30.3%±3.1 ERTU, p=NS). Body weight and glucose levels remained unchanged. Phosphorylation of STAT3(Y705) was increased at the 10th min of R in EMPA and DAPA groups, while was not altered by ERTU. Phosphorylation and expression of PI3K, Akt and eNOS did not differ among groups, indicating that the cardioprotective mechanism is independent of RISK pathway. Real time PCR analysis revealed that il-6 mRNA levels were not affected by the treatments. Notably, we observed increased mRNA levels of tgf-β in both EMPA and DAPA groups, which indicates that cardioprotection is mediated through STAT3/TGF-β crosstalk.

Conclusion(s)

Short-term EMPA and DAPA, but not ERTU treatment for 7 days reduces IS in healthy, non-diabetic mice through STAT3/TGF-β mediated pathways.

Funding Acknowledgement

Type of funding sources: None.

Acute administration of the olive constituent, oleuropein, combined with post-conditioning mechanism exerts cardioprotective effects by modulating oxidative defense

Background/Introduction

Oleuropein (oleu), the main polyphenolic constituent of olive, has cardioprotective effects against ischemia (I) – reperfusion (R) injury (IRI) when administered chronically.

Purpose

We aimed to assess the cardioprotection afforded by acute administration of oleu, to evaluate the underlying mechanism and whether it could enhance or imbed the cardioprotective manifestation of ischemic postconditioning (PostC).

Methods

Male rabbits were subjected to I/R (30/180 min) and randomized to 7 groups: (i) Control (ii) PostC: 8 cycles of 30-sec I/R at the onset of R; (iii) Oleu (100 mg/kg, iv bolus) at the 20th min of I; (iv) Oleu+NOS inhibitor (L-NAME, 10mg/kg); (v) Oleu+PI3K/Akt inhibitor (wortmannin, 60 μg/kg); (vi) Oleu+JAK2 inhibitor (AG490, 6μg/kg/min) and (vii) Oleu+PostC. Additionally, male C57BL6/J mice, subjected to I/R (30/180 min) and randomized to 4 groups: (i) Control; (ii) PostC: 3 cycles of 10-sec I/R at the onset of R; (iii) Oleu (350 mg/kg, iv bolus) at the 20th min of I; (iv) Oleu+PostC. In both animal models, infarct size (IS) expressed as percentage of infarct to area at risk ratio (I/R, %) was determined. Oleu's effect on cardiomyocytes was measured by MTT assay in adult rat cardiomyocytes exposed to simulated I (SI) and reoxygenation. We also assessed the effect of oleu on mitochondrial permeability transition pore (mPTP) through calcium retention capacity (CRC) assay and on cGMP accumulation in rat aortic smooth muscle cells. In a mouse model of IRI, we explored the effect of oleu on the recruitment of inflammatory monocytes and neutrophils in the IR heart using flow cytometry, whereas the effect of oleu on Nrf-2 signaling pathway-related genes was analyzed by western blot.

Results

In both animal models acute oleu administration reduced significantly the IS compared to the control group. None of the inhibitors of the classic cardioprotective pathways influence its IS limiting effects in rabbits. Combination of oleu with PostC caused further limitation of IS compared to PostC in both animal models (I/R Rabbits: 14.6±0.9 vs. 26.7±2.7%, p&lt;0.01 and I/R mice: 11.5±1.8 vs. 20.3±1.8%, p&lt;0.01). Oleu had a direct protective effect on cardiomyocytes since it significantly increased their viability following SI-reoxygenation injury as compared to non-treated cells. Oleu did not inhibit the calcium induced mPTP opening in isolated mitochondria and did not increase cGMP production. Oleu, PostC and their combination reduced inflammatory monocytes infiltration into the heart and the circulating monocytes. Oleu conferred additive cardioprotection on top of PostC, via increasing the expression of Nrf-2 and its downstream targets (HO-1 and SOD-2).

Conclusion(s)

Acute oleu administration combined with PostC provides robust and synergistic cardioprotection in experimental models of IRI by inducing antioxidant defense genes through Nrf-2 axis and independently of the classic cardioprotective signaling pathways.

Funding Acknowledgement

Type of funding sources: None.

Myocardial infarction or acute coronary syndrome with non-obstructive coronary arteries and sudden cardiac death: a missing connection

Myocardial infarction with non-obstructive coronary arteries or any acute coronary syndrome (ACS) with normal or near-normal (non-obstructive) coronary arteries (ACS-NNOCA) is an heterogeneous clinical entity, which includes different pathophysiology mechanisms and is challenging to treat. Sudden cardiac death (SCD) is a catastrophic manifestation of ACS that is crucial to prevent and treat urgently. The concurrence of the two conditions has not been adequately studied. This narrative review focuses on the existing literature concerning ACS-NNOCA pathophysiology, with an emphasis on SCD, together with risk and outcome data from clinical trials. There have been no large-scale studies to investigate the incidence of SCD within ACS-NNOCA patients, both early and late in the disease. Some pathophysiology mechanisms that are known to mediate ACS-NNOCA, such as atheromatous plaque erosion, anomalous coronary arteries, and spontaneous coronary artery dissection are documented causes of SCD. Myocardial ischaemia, inflammation, and fibrosis are probably at the core of the SCD risk in these patients. Effective treatments to reduce the relevant risk are still under research. ACS-NNOCA is generally considered as an ACS with more 'benign' outcome compared to ACS with obstructive coronary artery disease, but its relationship with SCD remains obscure, especially until its incidence and effective treatment are evaluated.

Acute administration of the olive constituent, oleuropein, combined with ischemic postconditioning increases myocardial protection by modulating oxidative defense

Oleuropein, one of the main polyphenolic constituents of olive, is cardioprotective against ischemia reperfusion injury (IRI). We aimed to assess the cardioprotection afforded by acute administration of oleuropein and to evaluate the underlying mechanism. Importantly, since antioxidant therapies have yielded inconclusive results in attenuating IRI-induced damage on top of conditioning strategies, we investigated whether oleuropein could enhance or imbed the cardioprotective manifestation of ischemic postconditioning (PostC). Oleuropein, given during ischemia as a single intravenous bolus dose reduced the infarct size compared to the control group both in rabbits and mice subjected to myocardial IRI. None of the inhibitors of the cardioprotective pathways, l-NAME, wortmannin and AG490, influence its infarct size limiting effects. Combined oleuropein and PostC cause further limitation of infarct size in comparison with PostC alone in both animal models. Oleuropein did not inhibit the calcium induced mitochondrial permeability transition pore opening in isolated mitochondria and did not increase cGMP production. To provide further insights to the different cardioprotective mechanism of oleuropein, we sought to characterize its anti-inflammatory potential in vivo. Oleuropein, PostC and their combination reduce inflammatory monocytes infiltration into the heart and the circulating monocyte cell population. Oleuropein's mechanism of action involves a direct protective effect on cardiomyocytes since it significantly increased their viability following simulated IRI as compared to non-treated cells. Οleuropein confers additive cardioprotection on top of PostC, via increasing the expression of the transcription factor Nrf-2 and its downstream targets in vivo. In conclusion, acute oleuropein administration during ischemia in combination with PostC provides robust and synergistic cardioprotection in experimental models of IRI by inducing antioxidant defense genes through Nrf-2 axis and independently of the classic cardioprotective signaling pathways (RISK, cGMP/PKG, SAFE).

Chronic Empagliflozin Treatment Reduces Myocardial Infarct Size in Nondiabetic Mice Through STAT-3-Mediated Protection on Microvascular Endothelial Cells and Reduction of Oxidative Stress

Aims: Empagliflozin (EMPA) demonstrates cardioprotective effects on diabetic myocardium but its infarct-sparing effects in normoglycemia remain unspecified. We investigated the acute and chronic effect of EMPA on infarct size after ischemia-reperfusion (I/R) injury and the mechanisms of cardioprotection in nondiabetic mice. Results: Chronic oral administration of EMPA (6 weeks) reduced myocardial infarct size after 30 min/2 h I/R (26.5% ± 3.9% vs 45.8% ± 3.3% in the control group, p < 0.01). Body weight, blood pressure, glucose levels, and cardiac function remained unchanged between groups. Acute administration of EMPA 24 or 4 h before I/R did not affect infarct size. Chronic EMPA treatment led to a significant reduction of oxidative stress biomarkers. STAT-3 (signal transducer and activator of transcription 3) was activated by Y(705) phosphorylation at the 10th minute of R, but it remained unchanged at 2 h of R and in the acute administration protocols. Proteomic analysis was employed to investigate signaling intermediates and revealed that chronic EMPA treatment regulates several pathways at reperfusion, including oxidative stress and integrin-related proteins that were further evaluated. Superoxide dismutase and vascular endothelial growth factor were increased throughout reperfusion. EMPA pretreatment (24 h) increased the viability of human microvascular endothelial cells in normoxia and on 3 h hypoxia/1 h reoxygenation and reduced reactive oxygen species production. In EMPA-treated murine hearts, CD31-/VEGFR2-positive endothelial cells and the pSTAT-3(Y705) signal derived from endothelial cells were boosted at early reperfusion. Innovation: Chronic EMPA administration reduces infarct size in healthy mice via the STAT-3 pathway and increases the survival of endothelial cells. Conclusion: Chronic but not acute administration of EMPA reduces infarct size through STAT-3 activation independently of diabetes mellitus.

Effects of glucagon like peptide-1 receptor agonists and their combination with sodium-glucose cotransporter-2 inhibitors on myocardial deformation and work index in type 2 diabetes: 1 year follow up

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction:

Type-2 diabetes mellitus (T2DM) exacerbates mechanisms of atherosclerosis and heart failure.

Purpose

We investigated the effect of novel antidiabetic drugs, glucagon like peptide-1 receptor agonists (GLP-1RA) and sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and their combination on myocardial function.

Methods

A hundred-sixty T2DM patients (age: 58 ± 10years) were randomized to insulin (n = 40), liraglutide (n = 40), empagliflozin (n = 40) or their combination (GLP-1RA + SGLT-2i) (n = 40) as add-on to metformin. We measured at baseline and 1 year post-treatment: a) global LV longitudinal strain (GLS), systolic (GLSR) and diastolic (GLSR E) strain rate, global circumferential (GCS) and radial (GRS) strain, peak twisting (pTw), peak twisting velocity (pTwVel) and peak untwisting velocity (pUtwVel), b) global myocardial work index (GWI), global constructive (GCW) and global wasted work (GWW) derived by pressure-myocardial strain loops using speckle tracking imaging.

Results

After 1 year of treatment, all patients improved GLS, GCS, GRS and pUtwVel (p &lt; 0.05). GLP-1RA or GLP-1RA + SGLT-2i provided a greater increase of GLS (11.5% and 13% vs. 6.8% and 2.3%), GWI (12.7% and 17.4% vs. 3.1% and 2%), GCW (12.3% and 15% vs. 2.2% and 7.8%) and a greater reduction of GWW (38.7% and 41.6% vs. 13.5% and 4.9%) compared with insulin or SGLT-2i, despite a similar HbA1c reduction (p &lt; 0.05 for all comparisons) (Table). Patients under combined treatment with GLP-1RA + SGLT-2i achieved a 2-fold reduction of pTw and a 2-fold increase of pUtwVel than those under each one regimen or insulin (p &lt; 0.05). The dual therapy showed the greatest effect on measured myocardial markers in LVEF &lt; 55% (p &lt; 0.05).

Conclusions

One year treatment with GLP-1RA or combination of GLP-1RA and SGLT-2i resulted in a greater improvement of myocardial deformation and effective cardiac work than insulin or SGLT-2i treatment, independently of glycemic control in T2DM.

All patients (n = 160) Insulin (n = 40) GLP-1RA (n = 40) SGLT-2i (n = 40) GLP-1RA + SGLT-2i (n = 40) p-value GLS, % Baseline -16.4 ± 3.7 -16.4 ± 3.5 -16.2 ± 3.5 -17 ± 4 -16 ± 4 0.139 1 year -17.9 ± 3.9 -17.6 ± 4.2 -18.3 ± 3.5 -17.4 ± 3.4 -18.4 ± 4.7 0.003 GWI, mmHg% Baseline 1538 ± 430 1644 ± 416 1510 ± 403 1536 ± 535 1463 ± 362 0.116 1 year 1692 ± 412 1696 ± 377 1730 ± 318 1568 ± 456 1772 ± 499 0.006 pTw, deg Baseline 15.7 ± 6 16 ± 5.1 15.6 ± 5 15.2 ± 6 16.1 ± 8 0.910 1 year 14.6 ± 5.1 15.4 ± 5.4 14.4 ± 5.4 14.7 ± 4.6 14 ± 5 0.034 pUtwVel, deg/s Baseline -104 ± 42 -100 ± 44 -107 ± 41 -101 ± 28 -111 ± 54 0.550 1 year -116 ± 49 -107 ± 55 -114 ± 45 -108 ± 38 -134 ± 61 0.017 Table

Vascular conditioning prevents adverse left ventricular remodelling after acute myocardial infarction: a randomised remote conditioning study

AIMS

Remote ischemic conditioning (RIC) alleviates ischemia-reperfusion injury via several pathways, including micro-RNAs (miRs) expression and oxidative stress modulation. We investigated the effects of RIC on endothelial glycocalyx, arterial stiffness, LV remodelling, and the underlying mediators within the vasculature as a target for protection.

METHODS AND RESULTS

We block-randomised 270 patients within 48 h of STEMI post-PCI to either one or two cycles of bilateral brachial cuff inflation, and a control group without RIC. We measured: (a) the perfusion boundary region (PBR) of the sublingual arterial microvessels to assess glycocalyx integrity; (b) the carotid-femoral pulse wave velocity (PWV); (c) miR-144,-150,-21,-208, nitrate-nitrite (NOx) and malondialdehyde (MDA) plasma levels at baseline (T0) and 40 min after RIC onset (T3); and (d) LV volumes at baseline and after one year. Compared to baseline, there was a greater PBR and PWV decrease, miR-144 and NOx levels increase (p < 0.05) at T3 following single- than double-cycle inflation (PBR:ΔT0-T3 = 0.249 ± 0.033 vs 0.126 ± 0.034 μm, p = 0.03 and PWV:0.4 ± 0.21 vs -1.02 ± 0.24 m/s, p = 0.03). Increased miR-150,-21,-208 (p < 0.05) and reduced MDA was observed after both protocols. Increased miR-144 was related to PWV reduction (r = 0.763, p < 0.001) after the first-cycle inflation in both protocols. After one year, single-cycle RIC was associated with LV end-systolic volume reduction (LVESV) > 15% (odds-ratio of 3.75, p = 0.029). MiR-144 and PWV changes post-RIC were interrelated and associated with LVESV reduction at follow-up (r = 0.40 and 0.37, p < 0.05), in the single-cycle RIC.

CONCLUSION

RIC evokes "vascular conditioning" likely by upregulation of cardio-protective microRNAs, NOx production, and oxidative stress reduction, facilitating reverse LV remodelling.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov . Unique identifier: NCT03984123.

Levosimendan prevents doxorubicin-induced cardiotoxicity in time- and dose-dependent manner: implications for inotropy

AIMS

Levosimendan (LEVO) a clinically-used inodilator, exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains obscure. We investigated the effect and mechanism of different regimens of levosimendan on sub-chronic and chronic doxorubicin cardiotoxicity.

METHODS AND RESULTS

Based on preliminary in vivo experiments, rats serving as a sub-chronic model of doxorubicin-cardiotoxicity and were divided into: Control (N/S-0.9%), DXR (18 mg/kg-cumulative), DXR+LEVO (LEVO, 24 μg/kg-cumulative), and DXR+LEVO (acute) (LEVO, 24 μg/kg-bolus) for 14 days. Protein kinase-B (Akt), endothelial nitric oxide synthase (eNOS), and protein kinase-A and G (PKA/PKG) pathways emerged as contributors to the cardioprotection, converging onto phospholamban (PLN). To verify the contribution of PLN, phospholamban knockout (PLN-/-) mice were assigned to PLN-/-/Control (N/S-0.9%), PLN-/-/DXR (18 mg/kg), and PLN-/-/DXR+LEVO (ac) for 14 days. Furthermore, female breast cancer-bearing (BC) mice were divided into: Control (normal saline 0.9%, N/S 0.9%), DXR (18 mg/kg), LEVO, and DXR+LEVO (LEVO, 24 μg/kg-bolus) for 28 days. Echocardiography was performed in all protocols. To elucidate levosimendan's cardioprotective mechanism, primary cardiomyocytes were treated with doxorubicin or/and levosimendan and with N omega-nitro-L-arginine methyl ester (L-NAME), DT-2, and H-89 (eNOS, PKG, and PKA inhibitors, respectively); cardiomyocyte-toxicity was assessed. Single bolus administration of levosimendan abrogated DXR-induced cardiotoxicity and activated Akt/eNOS and cAMP-PKA/cGMP-PKG/PLN pathways but failed to exert cardioprotection in PLN-/- mice. Levosimendan's cardioprotection was also evident in the BC model. Finally, in vitro PKA inhibition abrogated levosimendan-mediated cardioprotection, indicating that its cardioprotection is cAMP-PKA dependent, while levosimendan preponderated over milrinone and dobutamine, by ameliorating calcium overload.

CONCLUSION

Single dose levosimendan prevented doxorubicin cardiotoxicity through a cAMP-PKA-PLN pathway, highlighting the role of inotropy in doxorubicin cardiotoxicity.

HEllenic Registry on Myocarditis SyndromES on behalf of Hellenic Heart Failure Association: The HERMES-HF Registry

AIMS

Despite the existence of many studies, there are still limited data about the characteristics of myocarditis in Greece. This led to the creation of the Greek Myocarditis Registry aiming to document the different symptoms and treatment of myocarditis, assess possible prognostic factors, and find similarities and differences to what is already published in literature. This paper is a preliminary descriptive analysis of this Registry.

METHODS AND RESULTS

We analysed data for the hospitalization period of all patients included in the Registry from December 2015 until November 2017. Statistics are reported as frequency (%) or median and inter-quartile range (IQR) as appropriate. In total, 146 patients were included; 83.3% of the patients reported an infection during the last 3 months. The most common symptom, regardless of the underlying infection, was chest pain (82.2%) followed by dyspnoea (18.5%), while the most common finding in clinical examination was tachycardia (26.7%). Presentation was more frequent in the winter months. ECG findings were not specific, with the repolarization abnormalities being the most frequent (60.3%). Atrial fibrillation was observed in two patients, both of whom presented with a reduced ventricular systolic function. Left ventricular ejection fraction changed significantly during the hospitalization [55% (IQR: 50-60%) on admission vs. 60% (IQR: 55-60%) on discharge, P = 0.0026]. Cardiac magnetic resonance was performed in 88 patients (61%), revealing mainly subepicardial and midcardial involvement of the lateral wall. Late gadolinium enhancement was present in all patients, while oedema was found in 39 of them. Only 11 patients underwent endomyocardial biopsy. Discharge medication consisted mainly of beta-blockers (71.9%) and angiotensin-converting enzyme inhibitors (41.8%), while 39.7% of the patients were prescribed both.

CONCLUSIONS

This preliminary analysis describes the typical presentation of myocarditis patients in Greece. It is a first step in developing a better prognostic model for the course of the disease, which will be completed after the incorporation of the patients' follow-up data.

Nitroglycerine limits infarct size through S-nitrosation of cyclophilin D: a novel mechanism for an old drug

AIMS

Nitroglycerine (NTG) given prior to an ischaemic insult exerts cardioprotective effects. However, whether administration of an acute low dose of NTG in a clinically relevant manner following an ischaemic episode limits infarct size, has not yet been explored.

METHODS AND RESULTS

Adult mice were subjected to acute myocardial infarction in vivo and then treated with vehicle or low-dose NTG prior to reperfusion. This treatment regimen minimized myocardial infarct size without affecting haemodynamic parameters but the protective effect was absent in mice rendered tolerant to the drug. Mechanistically, NTG was shown to nitrosate and inhibit cyclophilin D (CypD), and NTG administration failed to limit infarct size in CypD knockout mice. Additional experiments revealed lack of the NTG protective effect following genetic (knockout mice) or pharmacological inhibition (L-NAME treatment) of the endothelial nitric oxide synthase (eNOS). The protective effect of NTG was attributed to preservation of the eNOS dimer. Moreover, NTG retained its cardioprotective effects in a model of endothelial dysfunction (ApoE knockout) by preserving CypD nitrosation. Human ischaemic heart biopsies revealed reduced eNOS activity and exhibited reduced CypD nitrosation.

CONCLUSION

Low-dose NTG given prior to reperfusion reduces myocardial infarct size by preserving eNOS function, and the subsequent eNOS-dependent S-nitrosation of CypD, inhibiting cardiomyocyte necrosis. This novel pharmacological action of NTG warrants confirmation in clinical studies, although our data in human biopsies provide promising preliminary results.

P357 Remote ischemic post-conditioning may prevent cardiac remodeling within two years of STEMI by cardioprotective microRNA upregulation

Background

Remote ischemic post-conditioning attenuates ischemia-reperfusion injury in patients with STEMI. However, its biochemical mechanisms, including micro-RNA expression, and effects on cardiac remodeling have not been defined.

Methods

We examined 80 patients with STEMI and 20 healthy controls. All patients had been evaluated by cardiac echocardiography. The conditioning protocol utilised a single ischemic stimulus by brachial cuff inflation of both arms at 200mmHg for 5 minutes, while 20 patients underwent a sham conditioning procedure by way of cuff inflation omission after its placement. Blood samples were taken before and after the conditioning protocol; thus, the expression of microRNA-144,-150,-499 (cardioprotective action), -21, and -208 (remodeling stimuli) was quantified at baseline and after the ischemic conditioning procedure, by polymerase chain reaction. Additionally, cardiac remodeling was evaluated by repeat echocardiography after a 2-year follow-up period, in 40 patients.

Results

Our conditioning protocol resulted in a statistically significant increase in miR-144,-150, -499, -21, and -208 expression (55.9 vs 7.4/U6sn, p &lt; 0.001; 3.4 vs 1.8/U6sn, p &lt; 0.05, p = 0.01; 3.5 vs 1.6/U6sn, p &lt; 0.001; 2.1 vs 1.2/U6sn; 2.4 vs 1.9/U6sn) compared to baseline; none of the aforementioned measurements was affected by the sham procedure. Furthermore, both left-ventricular end-diastolic (LVEDV) and end-systolic volume (LVESV) were decreased after the 2-year follow-up period (from 99.3 ± 6.7 to 85.9 ± 5.7, p= 0.004, and from 55.3± 6.1 to 48.6± 5.2, p= 0.04, respectively). In addition, the increase in mir-144 and mir-499 was significantly correlated with a decrease in LVESV (r=-0.355, p &lt; 0.05; r=-0.368, p &lt; 0.05, respectively), while the increase in mir-499 was also significantly correlated with a decrease in LVEDV (r=-0.374, p &lt; 0.05) at follow-up.

Conclusion

Remote ischemic conditioning may prevent adverse myocardial remodelling within 2 years of the index ischemic event, likely by up-regulation of cardio-protective microRNAs expression.

P1588 micro rna expression profiling may predict cardiac remodeling after stemi

Background

MicroRNAs have been recognised as important modulators of cardiovascular function. However, their profiling in ischemic heart disease and contribution to cardiac remodeling has not been defined.

Methods

We examined 40 patients with STEMI and 20 healthy controls. MicroRNA expression profiling was carried out within 48 hours of the index ischemic event, measuring the expression of microRNA-144,-150,-499 (cardioprotective action), -21, and -208 (remodeling stimuli). In addition, every patient was evaluated by echocardiography, which was repeated after a 2-year follow-up period.

Results

Left-ventricular end-systolic volume (LVESV) and left-ventricular end-diastolic volume (LVEDV) decreased (from 57.7± 6.3 to 48.6± 5.2, p &lt; 0.05 and from 102.1± 7.1 to 85.9 ± 5.7, p &lt; 0.05, respectively) while the ratio of early mitral inflow velocity to mitral annular early diastolic velocity (E/e’) did not change (from 9.32± 0.6 to 9.56± 0.8, p= NS). Mir-208 and -499 expression within 48 hours of STEMI (1.91± 0.43/U6sn and 1.7± 0.48/U6sn respectively) were significantly positively correlated with a reduction in LVESV, LVEDV, and E/e’. In specific, mir-208 expression was associated with an absolute (r= -0.41, p &lt; 0.05) and a percent reduction (r=-0.45, p= 0.03) in LVEDV and an absolute reduction in E/E’ (r= 0.46, p &lt; 0.05), while mir-499 was associated with an absolute (r= -0.4, p &lt; 0.05) and percent reduction (p= -0.38, p &lt; 0.05) in LVESV. Mir-499 median value (1.78[1.292.01]) predicted reverse remodelling (LVESV reduction by &gt;15%) with satisfactory specificity (0.82).

Conclusion

Mir- 208 and -499 expression may contribute to cardiac remodeling after STEMI, while mir-499 could be used as a prognostic marker of reverse remodeling.

Arrhythmogenic Inflammatory Cardiomyopathy in Autoimmune Rheumatic Diseases: A Challenge for Cardio-Rheumatology

Ventricular arrhythmia (VA) in autoimmune rheumatic diseases (ARD) is an expression of autoimmune inflammatory cardiomyopathy (AIC), caused by structural, electrical, or inflammatory heart disease, and has a serious impact on a patient’s outcome. Myocardial scar of ischemic or nonischemic origin through a re-entry mechanism facilitates the development of VA. Additionally, autoimmune myocardial inflammation, either isolated or as a part of the generalized inflammatory process, also facilitates the development of VA through arrhythmogenic autoantibodies and inflammatory channelopathies. The clinical presentation of AIC varies from oligo-asymptomatic presentation to severe VA and sudden cardiac death (SCD). Both positron emission tomography (PET) and cardiovascular magnetic resonance (CMR) can diagnose AIC early and be useful tools for the assessment of therapies during follow-ups. The AIC treatment should be focused on the following: (1) early initiation of cardiac medication, including ACE-inhibitors, b-blockers, and aldosterone antagonists; (2) early initiation of antirheumatic medication, depending on the underlying disease; and (3) potentially implantable cardioverter–defibrillator (ICD) and/or ablation therapy in patients who are at high risk for SCD.

P4461Chronic administration of Empagliflozin induces cardioprotection in vivo in absence of diabetes mellitus

Background/Introduction

We have recently shown that empagliflozin (EMPA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor approved for type 2 diabetes mellitus management reduces myocardial infarct size in diabetic mice undergone ischemia/reperfusion (I/R) after chronic administration. However its effect on non-diabetic myocardium remains unspecified.

Purpose

We aimed to investigate: (i) the effect of EMPA on myocardial function and infarct size after I/R in healthy mice, in the absence of diabetes mellitus, (ii) the underlying signaling pathways, (iii) its effects on cell survival in rat embryonic-heart-derived cardiomyoblasts (H9C2) treated with the inhibitor of STAT3, STATTIC.

Methods

C57BL/6 mice were initially randomized into two groups, Control and EMPA (n=7 per group) and treated with 5% DMSO in water for injection and EMPA at a dose of 10mg/kg/day with 5% DMSO in water for injection, respectively, for 6 weeks. After this period, the mice were subjected to 30 minutes of I and 2 hours of R and infarct size was evaluated. Body weight, blood pressure, blood glucose levels and left ventricular shortening measurements by echocardiography, were taken at baseline and at the end of the treatment. Furthermore, in order to assess potential differences in the signaling cascades involved at different time points of reperfusion, additional mice were randomized into Control and EMPA groups which were furtherly subdivided into groups (n=4) of 10' and (n=4) of 120' of reperfusion each. The mice were subjected to I/R and myocardial biopsies were obtained for the assessment of the signaling cascade at the 10th and 120th minutes of reperfusion. H9C2 cells subjected to ischemia–reoxygenation were treated with STATIC (0.5, 1, and 10 μM) during the 3 hours of reoxygenation and evaluated for viability.

Results

Body weight, blood pressure and glucose levels remained unchanged between the groups. We observed no statistically significant change in left ventricular fractional shortening in both groups at baseline (41.0% ± 1.92 vs 40.5% ± 2.7) and after the end of the 6th week (42.7% ± 2.8 vs 40.9% ± 4.1). Infarct size was significantly reduced in EMPA group compared to the Control one (29.5% ± 3.0 vs 45.8% ± 3.2, p<0.05). Phosphorylation of STAT3 was significantly increased at the 10th minute of reperfusion but remained unchanged at the 120th compared to control. The contribution of STAT3 in EMPA-mediated effects was evaluated in H9C2 cells using different doses of STATIC; our results indicate that EMPA completely lost its activity when STAT3 is inhibited. However STATIC per se induces cell death even at low doses.

Conclusion(s)

EMPA reduces infarct size in healthy mice indicating that its cardioprotective effect is independent of the presence of diabetes mellitus. STAT3 activation can be considered as a cardioprotective mechanism of EMPA, however other signaling pathways could be involved in EMPA mechanism of action and are currently under investigation.

P3488Mechanistic insight on the cardioprotective effect of levosimendan against doxorubicin induced cardiomyopathy: Pivotal role of PKA signaling

Background

Levosimendan (LEVO) an inodilator indicated for the treatment of heart failure exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains elusive. We have previously shown that LEVO exerts cardioprotection against DXR-induced cardiomyopathy in a rat in vivo model, in a PKA/PKG-dependent manner.

Purpose

We sought to elucidate the mechanism of LEVO's induced cardioprotection and clarify the contribution of PKG and PKA pathways converging onto phospholamban (PLN).

Methods

As previously observed, LEVO at a dose of 24μg/kg protects against DXR cardiotoxicity, with protein kinase B (Akt)/ endothelial nitric oxide synthase (eNOS) and protein kinase A and G (PKA/PKG) pathways emerging as the main contributors to cardioprotection. Moreover, phospholamban seems to be the end-target of the signaling cascade. To verify the contribution of phospholamban, phospholamban deficient mice (PLN−/−) were assigned to PLN−/−/DXR (18mg/kg) and PLN−/−/DXR+LEVO (acute) (LEVO bolus, 24 μg/kg) groups for 14 days. Echocardiographic analysis was conducted in all groups and protocols. Furthermore, in order to solidify the mechanism of LEVO-mediated cardioprotection, primary adult ventricular murine cardiomyocytes (AVMCs) were isolated and treated with doxorubicin or/and LEVO as well with L-NAME, DT-2 and H-89 (eNOS, PKG and PKA inhibitors, respectively) and cardiomyocyte-toxicity was assessed.

Results

In the transgenic PLN−/− mice, LEVO did not exert cardioprotection, whilst the co-administration of doxorubicin and levosimendan led to an impaired Left ventricular function [FS (%): PLN−/−/Control: 39.01±0.42 vs PLN−/−/DXR: 38.12±0.51 in (NS); PLN−/−/DXR+LEVO: 35.38±0.86 (**p<0.01 vs PLN−/−/Control, *p<0.05 vs PLN−/−/DXR]. The latter data suggest that phospholamban is crucial for LEVO's cardioprotective effect. Finally, by investigating the contribution of different molecular pathways -shown to be induced by LEVO in vivo- on the AVMCs, we found that only PKA inhibition by H-89, abrogated LEVO-mediated cytoprotection, indicating that the effect is cAMP-PKA dependent.

Conclusions

Single-dose LEVO prevented DXR cardiotoxicity through a cAMP-PKA-phospholamban pathway, highlighting the role of inotropy in DXR cardiotoxicity. These preclinical data can stand as promising grounds for further clinical investigations.

P940Effects of IQOS smoking on vascular function, coronary flow reserve, myocardial deformation and myocardial work index during one month of use

Background

IQOS smoking (heat-no burn smoke product) is proposed to reduce harm compared to conventional smoking. We examined its effects on vascular function, myocardial deformation and ventricular arterial coupling.

Methods

Thirty-seven current smokers (mean age 48±5 years, >20 cigarettes /day) without cardiovascular disease and 20 healthy subjects with similar age sex and risk factors participated in the study. All subjects were instructed to smoke only IQOS for one month. Measurements were performed at baseline and 1 month after smoking IQOS. we measured a) the aortic PWV (PWV) and central aortic systole blood pressure (SBPc) by Complior; b) the exhaled CO level (parts per million-ppm) as a smoking status marker; and c) brachial systolic (SBP)and diastolic (DBP) blood pressure and heart rate (HR) a) flow mediated dilation (FMD) of the brachial artery b) coronary flow reserve (CFR) after adenosine infusion by Doppler echocardiography and c) global longitundinal strain (GLS) peak twisting and untwisting velocity and myocardial work index derived by pressure –myocardial strain loops by speckle tracking imaging PWV to GLS ratio was also used as a marker of ventricular arterial coupling

Results

At baseline exhaled CO, PWV, SBPc, FMD, PWV/GLS ratio, myocardial work index and peak untwisting velocity were higher and CFR was lower in smokers compared to controls (14.9±7 vs. 4.2±1 ppm, p<0.001, 8.7±1.4 vs 10.0±1.6 m/s, p<0.05; 118±16 vs 110±7 mmHg p<0.001, 6.9±2 vs 9.5±2% p<0.001, −0.61±0.21 vs. −0.45±0.11 m/sec%, p<0.001, 1926±284 vs 1826±300 mmHg% p=0.04, −122±36 vs −95±25 deg/sec, p=0.02, 2.5±0.9 vs. 3.1±0.8 p=0.001 respectively). In the chronic phase we observed a significant improvement of FMD, CFR, GLS, PWV/GLS, myocardial work index and peak untwisting velocity compared to baseline (12±2% vs. 6.9±2%, p=0.03; 3.2±0.6 vs. 2.5±0.9 p=0.001; −19.3±2.2% vs. −21.1±2.8%, p=0.001; −0.61±0.21 vs. −0.47±0.12 m/sec% p=0.03; 1926±284 vs 1830±343 mmHg% p=0.03, −122±36 vs −105±25 deg/sec, p=0.03, respectively) in parallel with reduction of the exhaled CO (14.9±7 vs. 6±4.9 ppm, p<0.001). HR remained unchanged throughout the study and there was a borderline reduction of central aortic systolic blood pressure (118±16 vs. 114±19 mmHg, p=0.048).

Conclusions

Replacement of conventional cigarettes with IQOS results in improved LV longitundinal myocardial deformation, LV untwisting and reduced LV myocardial work index possibly linked to the concomitant improvement of aortic elasticity, endothelial and coronary microcirculatory function and ventricular-arterial coupling within 1 month.

A pragmatic approach to the use of inotropes for the management of acute and advanced heart failure: An expert panel consensus

Inotropes aim at increasing cardiac output by enhancing cardiac contractility. They constitute the third pharmacological pillar in the treatment of patients with decompensated heart failure, the other two being diuretics and vasodilators. Three classes of parenterally administered inotropes are currently indicated for decompensated heart failure, (i) the beta adrenergic agonists, including dopamine and dobutamine and also the catecholamines epinephrine and norepinephrine, (ii) the phosphodiesterase III inhibitor milrinone and (iii) the calcium sensitizer levosimendan. These three families of drugs share some pharmacologic traits, but differ profoundly in many of their pleiotropic effects. Identifying the patients in need of inotropic support and selecting the proper inotrope in each case remain challenging. The present consensus, derived by a panel meeting of experts from 21 countries, aims at addressing this very issue in the setting of both acute and advanced heart failure.

Investigating and re-evaluating the role of glycogen synthase kinase 3 beta kinase as a molecular target for cardioprotection by using novel pharmacological inhibitors

AIMS

Glycogen synthase kinase 3 beta (GSK3β) link with the mitochondrial Permeability Transition Pore (mPTP) in cardioprotection is debated. We investigated the role of GSK3β in ischaemia (I)/reperfusion (R) injury using pharmacological tools.

METHODS AND RESULTS

Infarct size using the GSK3β inhibitor BIO (6-bromoindirubin-3'-oxime) and several novel analogues (MLS2776-MLS2779) was determined in anaesthetized rabbits and mice. In myocardial tissue GSK3β inhibition and the specificity of the compounds was tested. The mechanism of protection focused on autophagy-related proteins. GSK3β localization was determined in subsarcolemmal (SSM) and interfibrillar mitochondria (IFM) isolated from Langendorff-perfused murine hearts (30'I/10'R or normoxic conditions). Calcium retention capacity (CRC) was determined in mitochondria after administration of the inhibitors in mice and in vitro. The effects of the inhibitors on mitochondrial respiration, reactive oxygen species (ROS) formation, ATP production, or hydrolysis were measured in SSM at baseline. Cyclosporine A (CsA) was co-administered with the inhibitors to address putative additive cardioprotective effects. Rabbits and mice treated with MLS compounds had smaller infarct size compared with control. In rabbits, MLS2776 and MLS2778 possessed greater infarct-sparing effects than BIO. GSK3β inhibition was confirmed at the 10th min and 2 h of reperfusion, while up-regulation of autophagy-related proteins was evident at late reperfusion. The mitochondrial amount of GSK3β was similar in normoxic SSM and IFM and was not altered by I/R. The inhibitors did not affect CRC or respiration, ROS and ATP production/hydrolysis at baseline. The co-administration of CsA ensured that cardioprotection was CypD-independent.

CONCLUSION

Pharmacological inhibition of GSK3β attenuates infarct size beyond mPTP inhibition.

Sphenopalatine ganglion block: an external gate to modulate cardiac autonomic tone and suppress premature ventricular beats?

Background

Autonomic modulation is used for treating various cardiovascular diseases, such as cardiac arrhythmias. Sphenopalatine ganglion (SPG) block is an easy, non-invasive therapy for migraine with a potential cardiovascular impact that remains unclear. In this study, we sought to assess the effect of SPG block on cardiac autonomic tone, as expressed by heart rate variability (HRV), and on ventricular arrhythmogenesis.

Methods

Forty patients (14 male and 26 female) suffering from migraine were randomized by 1:1 to SPG block or placebo (controls) and HRV parameters were evaluated 1 hour before and hourly after the intervention. Twenty-four additional patients (11 men and 13 women) with premature ventricular contractions (PVCs) from the right ventricular outflow tract underwent the same randomization and the number of PVCs was assessed during 1 hour before and every hour after treatment. Values were summarized as median (1st-3rd quartile).

Results

During the first four hours after SPG block, an increase in mean RR [883 (IQR, 869-948) vs. 839 (IQR, 806-887) ms at baseline, P<0.01], SDNN [64 (IQR, 59-69) vs. 51 (IQR, 47-55) ms, P<0.01], SDANN [39 (IQR, 36-43) vs. 27 (IQR, 22-29) ms, P<0.01], ASDNN [51 (IQR, 47-53) vs. 40 (IQR, 37-44) ms, P<0.01], rMSSD [30 (IQR, 27-32) vs. 25 (IQR, 23-27) ms, P<0.01], VLF [26 (IQR, 24-29) vs. 23 (IQR, 22-25) ms², P<0.01] and HF [14 (IQR, 11-16) vs. 11 (IQR, 9-12) ms², P<0.01], along with a decrease in LF/HF ratio [1.7 (IQR, 1.4-1.9) vs. 2.0 (IQR, 1.7-2.5), P<0.01] was observed in patients with migraine. In patients with PVCs, the number of ectopic ventricular beats per hour was decreased for the first five hours following SPG block [360 (IQR, 264-850) from 956 (IQR, 545-1,412), P<0.001]. No such differences were observed in controls.

Conclusions

SPG block is associated with a transient increase in those HRV parameters that mainly express parasympathetic activity. It is also followed by a significant decrease in ventricular arrhythmic burden. These findings imply an effect on cardiac autonomic tone with a potential favorable clinical impact on arrhythmogenesis.

Opposite relations of epicardial adipose tissue to left atrial size in paroxysmal and permanent atrial fibrillation

Objectives:

Atrial fibrillation has been associated with obesity in epidemiological studies. Epicardial adipose tissue is an ectopic fat depot in the proximity of atria, with endocrine and inflammatory properties that is implicated in the pathophysiology of atrial fibrillation. Inflammation also has a role in atrial arrhythmogenesis. The aim of this study was to investigate the potential relations of epicardial adipose tissue to left atrial size and to adiponectin and the pro-inflammatory mediators, high-sensitivity C-reactive protein, and interleukin-6 in paroxysmal and permanent atrial fibrillation.

Methods:

This was a cross-sectional study of 103 atrial fibrillation patients, divided into two subgroups of paroxysmal and permanent atrial fibrillation, and 81 controls, in sinus rhythm. Echocardiography was used for estimation of epicardial adipose tissue and left atrial size and high-sensitivity C-reactive protein, interleukin-6 and adiponectin were measured in all subjects.

Results:

Atrial fibrillation patients had significantly larger epicardial adipose tissue compared with controls (0.43 ± 0.17 vs 0.34 ± 0.17 cm, p = 0.002). Atrial fibrillation presence was independently related to epicardial adipose tissue thickness (b = 0.09, p = 0.002). Opposite associations of epicardial adipose tissue with left atrial volume existed in atrial fibrillation subgroups; in the paroxysmal subgroup, epicardial adipose tissue was directly related to left atrial volume (R = 0.3, p = 0.03), but in the permanent one the relation was inverse (R = −0.7, p < 0.0001). Adiponectin, high-sensitivity C-reactive protein and interleukin-6 were elevated in both atrial fibrillation groups. Only interleukin-6 was related to epicardial adipose tissue size.

Conclusion:

Opposite associations of epicardial adipose tissue with left atrial size in paroxysmal and permanent Atrial fibrillation and elevated inflammatory markers, suggest a role of epicardial adipose tissue and inflammation in the fibrotic and remodeling process.

Empagliflozin Limits Myocardial Infarction in Vivo and Cell Death in Vitro: Role of STAT3, Mitochondria, and Redox Aspects

Empagliflozin (EMPA), a drug approved for type 2 diabetes management, reduced cardiovascular death but is unknown if it reduces myocardial infarction. We sought to investigate: (i) the effect of EMPA on myocardial function and infarct size after ischemia/reperfusion in mice fed with western diet (WD), (ii) the underlying signaling pathways, (iii) its effects on cell survival in rat embryonic-heart-derived cardiomyoblasts (H9C2) and endothelial cells (ECs). To facilitate the aforementioned aims, mice were initially randomized in Control and EMPA groups and were subjected to 30 min ischemia and 2 h reperfusion. EMPA reduced body weight, blood glucose levels, and mean arterial pressure. Cholesterol, triglyceride, and AGEs remained unchanged. Left ventricular fractional shortening was improved (43.97 ± 0.92 vs. 40.75 ± 0.61%) and infarct size reduced (33.2 ± 0.01 vs. 17.6 ± 0.02%). In a second series of experiments, mice were subjected to the above interventions up to the 10th min of reperfusion and myocardial biopsies were obtained for assessment of the signaling cascade. STAT3 was increased in parallel with reduced levels of malondialdehyde (MDA) and reduced expression of myocardial iNOS and interleukin-6. Cell viability and ATP content were increased in H9C2 and in ECs. While, STAT3 phosphorylation is known to bestow infarct sparing properties through interaction with mitochondria, we observed that EMPA did not directly alter the mitochondrial calcium retention capacity (CRC); therefore, its effect in reducing myocardial infarction is STAT3 dependent. In conclusion, EMPA improves myocardial function and reduces infarct size as well as improves redox regulation by decreasing iNOS expression and subsequently lipid peroxidation as shown by its surrogate marker MDA. The mechanisms of action implicate the activation of STAT3 anti-oxidant and anti-inflammatory properties.

Saffron (Crocus sativus) intake provides nutritional preconditioning against myocardial ischemia-reperfusion injury in Wild Type and ApoE(-/-) mice: Involvement of Nrf2 activation

BACKGROUND AND AIMS

Saffron is an antioxidant herbal derivative; however, its efficacy as a nutritional cardioprotective agent has not been fully elucidated. We investigated the cardioprotective properties of a standardized saffron aqueous extract (SFE) against ischemia/reperfusion (I/R) injury in Wild-Type (WT) and ApoE^(-/-) mice and the underlying molecular mechanisms.

METHODS AND RESULTS

WT and ApoE^(-/-) mice were subjected to 30 min I and 2 h R, with the following per os interventions for 4 weeks: 1) WT Control Group, receiving Water for Injection (WFI); 2) WT Crocus Group, receiving SFE at a dose of 60 mg/kg/day; 3) WT Crocus + Wort group, receiving SFE as described above and wortmannin at a dose of 60 μg/kg bolus 15 min before R; 4) ApoE^(-/-) Control Group, receiving WFI; 5) ApoE^(-/-) Crocus Group, receiving SFE at a dose of 60 mg/kg/day and 6) ApoE^(-/-) Crocus + Wort: receiving SFE as described above and wortmannin at a dose of 60 μg/kg bolus, 15 min before R. Ischemic area/area at risk (I/R%) ratio was measured. Blood samples and ischemic myocardial tissue were collected at the 10th min of reperfusion for assessment of troponin I, malondialdehyde (MDA), nitrotyrosine (NT), p-eNOS, eNOS, p-Akt, Akt, p-p42/p-p44, p-GSK3β, GSK3β, IL-6, Nrf2, HO-1 and MnSOD expression. The effect of SFE on Nrf2 expression was also evaluated in vitro. SFE reduced infarct size in WT (16.15 ± 3.7% vs 41.57 ± 2.48%, ***p < 0.001) and in ApoE^(-/-) mice (16.14 ± 1.47% vs 45.57 ± 1.73%, ***p < 0.001). The administration of wortmannin resulted in partial inhibition of the infarct size limitation efficacy of SFE (in both WT and Apo-E^(-/-) mice). Mice receiving SFE showed increased levels of eNOS, p-Akt, p-ERK1/2, p-44/p-42 and p-GSK3β-Ser9 and reduced expression of IL-6 and iNOS; furthermore, SFE reduced the levels of MDA and NT. SFE induced Nrf2 expression and its downstream targets, HO-1 and MnSOD in the myocardium of the treated animals, and induced Nrf2 expression in vitro in a dose-dependent manner.

CONCLUSIONS

SFE limits myocardial infarction in Wild-Type and ApoE^(-/-) mice in a multifaceted manner including activation of Akt/eNOS/ERK1/2/GSK3-β and through Nrf2 pathway, bestowing antioxidant protection against I/R.

Patients with Acute Coronary Syndrome are at High Risk Prior to the Event and Lipid Management is Underachieved Pre- and Post- Hospitalization

BACKGROUND

Current European Guidelines suggest the use of cardiovascular risk categories and also recommend using high-intensity statins for patients with acute coronary syndromes (ACS).

OBJECTIVE

We examined the risk of ACS patients prior to the event, as well as the overall use and intensity of statins.

METHODS

We enrolled 687 ACS patients (mean age 63 years, 78% males). Low-density lipoprotein cholesterol (LDL-C) levels upon admission were used to assess attainment of LDL-C targets. Patients were categorized as very high, high, moderate and low risk based on their prior to admission cardiovascular (CV) risk. We examined statin use and dosage intensity among patients discharged from the hospital. Patients were followed for a median period of 189 days.

RESULTS

The majority of the patients (n=371, 54%) were at very high CV risk prior to admission, while 101 patients were at high risk (15%), 147 (21%) moderate risk and 68 (10%) low risk. Interestingly, LDL-C target attainment decreased as the risk increased (p<0.001). The majority (96%) of patients received statins at discharge; however, most of them (60.4%) received low/moderate intensity statins and just 35.9% received the suggested by the Guidelines high-intensity dose of statins. At follow-up, the rate of patients at high-intensity dose of statins remained similar (34.8%); 6% received no statins at all at follow-up.

CONCLUSION

According to our study, the majority of ACS patients are already at high risk prior to their admission. Further, LDL-C targets are underachieved prior to the event and high-intensity statins are underutilized in ACS patients at, and post-discharge.

Reciprocal regulation of eNOS, H2S and CO-synthesizing enzymes in human atheroma: Correlation with plaque stability and effects of simvastatin

The molecular and cellular mechanisms underlying plaque destabilization remain obscure. We sought to elucidate the correlation between NO, H₂S and CO-generating enzymes, nitro-oxidative stress and plaque stability in carotid arteries. Carotid atherosclerotic plaques were collected from 62 patients who had undergone endarterectomy due to internal artery stenosis. Following histological evaluation the plaques were divided into stable and unstable ones. To investigate the impact of simvastatin we divided patients with stable plaques, into those receiving and to those not receiving simvastatin. Expression and/or levels of p-eNOS/eNOS, pAkt/t-Akt, iNOS, cystathionine beta synthase (CBS), cystathionine gamma lyase (CSE), heme oxygenase-1(HO-1), soluble guanyl cyclase sGCα1, sGCβ1, NOX-4 and HIF-1α were evaluated. Oxidative stress biomarkers malondialdehyde (MDA) and nitrotyrosine (NT) were measured. NT levels were decreased in stable plaques with a concomitant increase of eNOS phosphorylation and expression and Akt activation compared to unstable lesions. An increase in HIF-1α, NOX-4, HO-1, iNOS, CBS and CSE expression was observed only in unstable plaques. 78% of patients under simvastatin were diagnosed with stable plaques whereas 23% of those not receiving simvastatin exhibited unstable plaques. Simvastatin decreased iNOS, HO-1, HIF-1α and CSE whilst it increased eNOS phosphorylation. In conclusion, enhanced eNOS and reduced iNOS and NOX-4 were observed in stable plaques; CBS and CSE positively correlated with plaque vulnerability. Simvastatin, besides its known effect on eNOS upregulation, reduced the HIF-1α and its downstream targets. The observed changes might be useful in developing biomarkers of plaque stability or could be targets for pharmacothepary against plaque vulnerability.

Effect of hypercholesterolaemia on myocardial function, ischaemia-reperfusion injury and cardioprotection by preconditioning, postconditioning and remote conditioning

Hypercholesterolaemia is considered to be a principle risk factor for cardiovascular disease, having direct negative effects on the myocardium itself, in addition to the development of atherosclerosis. Since hypercholesterolaemia affects the global cardiac gene expression profile, among many other factors, it results in increased myocardial oxidative stress, mitochondrial dysfunction and inflammation triggered apoptosis, all of which may account for myocardial dysfunction and increased susceptibility of the myocardium to infarction. In addition, numerous experimental and clinical studies have revealed that hyperlcholesterolaemia may interfere with the cardioprotective potential of conditioning mechanisms. Although not fully elucidated, the underlying mechanisms for the lost cardioprotection in hypercholesterolaemic animals have been reported to involve dysregulation of the endothelial NOS-cGMP, reperfusion injury salvage kinase, peroxynitrite-MMP2 signalling pathways, modulation of ATP-sensitive potassium channels and apoptotic pathways. In this review article, we summarize the current knowledge on the effect of hypercholesterolaemia on the non-ischaemic and ischaemic heart as well as on the cardioprotection induced by drugs or ischaemic preconditioning, postconditioning and remote conditioning. Future perspectives concerning the mechanisms and the design of preclinical and clinical trials are highlighted.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

Exposure to cigarette smoke abrogates the beneficial effect of ischemic postconditioning

Cigarette smoking is one of the risk factors for coronary artery disease. Although conditioning decreases infarct size in hearts from healthy animals, comorbidities may render it ineffective. We investigated the effects of cigarette smoke (CS) exposure on intracellular myocardial signaling, infarct size after ischemia-reperfusion, and the potential interference with ischemic conditioning. Exposure of mice to CS increased blood pressure, caused cardiac hypertrophy, and upregulated the nitric oxide synthatse (NOS)/soluble guanylate cyclase (sGC)/cGMP pathway. To test the effect of CS exposure on the endogenous cardioprotective mechanisms, mice were subjected to regional myocardial ischemia and reperfusion with no further intervention or application of preconditioning (PreC) or postconditioning (PostC). Exposure to CS did not increase the infarction compared with the room air (RA)-exposed group. PreC was beneficial for both CS and RA vs. nonconditioned animals. PostC was effective only in RA animals, while the infarct size-limiting effect was not preserved in the CS group. Differences in oxidative stress markers, Akt, and endothelial NOS phosphorylation and cGMP levels were observed between RA and CS groups subjected to PostC. In conclusion, exposure to CS does not per se increase infarct size. The beneficial effect of ischemic PreC is preserved in mice exposed to CS, as it does not affect the cardioprotective signaling; in contrast, PostC fails to protect CS-exposed mice due to impaired activation of the Akt/eNOS/cGMP axis that occurs in parallel to enhanced oxidative stress.

Ischaemic conditioning and targeting reperfusion injury: a 30 year voyage of discovery

To commemorate the auspicious occasion of the 30th anniversary of IPC, leading pioneers in the field of cardioprotection gathered in Barcelona in May 2016 to review and discuss the history of IPC, its evolution to IPost and RIC, myocardial reperfusion injury as a therapeutic target, and future targets and strategies for cardioprotection. This article provides an overview of the major topics discussed at this special meeting and underscores the huge importance and impact, the discovery of IPC has made in the field of cardiovascular research.

"Pistacia lentiscus L." reduces the infarct size in normal fed anesthetized rabbits and possess antiatheromatic and hypolipidemic activity in cholesterol fed rabbits

HYPOTHESIS/PURPOSE

The aim of the present study was to evaluate in vivo the potential anti-ischemic and antiatheromatic activity of Chios Mastic gum, the resin of the trunk and branches of "Pistacia lentiscus var. chia", used since antiquity in traditional Greek medicine. The main compounds of mastic are triterpenes, possessing phytosterol-like structures. This led to the hypothesis that mastic and particularly its neutral fraction, enriched in phytosterol-like compounds, possess antiatheromatic activities.

METHODS

Total Mastic Extract without Polymer (TMEWP) and the neutral mastic fraction (NMF) were administered orally for 6 weeks to normal fed and to cholesterol fed rabbits in the form of sunflower oil solution. All the animals were randomly divided into 6 groups, anesthetized and subjected to 30min ischemia of the heart, followed by 3h reperfusion: At the end of the experiment the area at risk and the infarct zone were determined with the aid of fluorescent particles and triphenyl tetrazolium chloride staining, and small segments of the ascending and descending aorta and the heart were taken for histologic examination. Blood samples were collected at different time points of ischemia and reperfusion, for malondialdehyde (MDA) evaluation as an index of lipid peroxidation, for total and LDL cholesterol determination and for evaluation of oxidized LDL.

RESULTS

In the normal fed animals the NMF and the TMEWP reduced significantly the infarct size, while in the hypercholesterolemic rabbits both treatments were ineffective. Atherosclerosis was detected in all the animals fed cholesterol enriched diet in the form of subintimal accumulation of lipids and foamy macrophages. There was no detection of atherosclerosis in Groups treated with TMEWP and NMF, which both reduced the total cholesterol levels by 47 and 88% respectively, whilst had not effect on LDL oxidation. TMEWP and NMF reduced the MDA concentration in normal fed rabbits, but had no effect on MDA levels in cholesterol fed animals. TMEWP and NMPF reduce the infarct size in normal animals and possess significant antiatheromatic and hypolipidemic activities in rabbits fed cholesterol enriched diet.

Cellular Communications in the Heart

Heart failure is one of the leading causes of morbidity and mortality worldwide. Cardiac remodelling is first an adaptive, becoming a maladaptive, compensatory mechanism that finally causes ventricular dysfunction independently of the etiology of the initial insult. In the present article the authors describe the elements of the human heart, examining their basic functions and their inter-communication under both normal and pathological circumstances. Cardiac myocytes carry out mechanical and electrical functions of the heart and cardiac fibroblasts maintain its structural integrity. Several factors can affect fibroblast activation and under pathological stress they transdifferentiate into myofibroblasts. Endothelial cells have complex biological functions, including the control of vascular permeability, vasomotion, regulation of haemostasis, immune responses and angiogenesis. The extracellular matrix is a complex architectural network consisting of a variety of proteins. Various routes using a plethora of products and mediators contribute to the cross-talk of the myocytes with endothelial cells, extracellular matrix and cardiac fibroblasts. A better understanding of the entire mechanism of cellular communication by the established or the more recently discovered agents will certainly emerge promising new perspectives when looking at the prevention of heart failure and leading to more substantial therapeutic interventions.

Hydrogen sulfide and PKG in ischemia-reperfusion injury: sources, signaling, accelerators and brakes

Over the past decade, hydrogen sulfide has emerged as an important cardioprotective molecule with potential for clinical applications. Although several pathways have been proposed to mediate the beneficial effects of H2S, the NO/cGMP axis has attracted significant attention. Recent evidence has suggested that cGMP-dependent protein kinase can lie both downstream and upstream of H2S. The current literature on this topic is reviewed and data from recent studies are integrated to propose a unifying model.

Effects of the olive tree leaf constituents on myocardial oxidative damage and atherosclerosis

The olive (Olea europaea) leaf is considered an important traditional herbal medicine utilized against infectious diseases, and for the treatment of diabetes and hypertension. Moreover, olive leaf constituents have been related to cardioprotection, probably due to their association with cellular redox modulating effects. The pathogenesis of certain common diseases, including those of the cardiovascular system, involves oxidative stress and tissue inflammation. Olive polyphenolic compounds, such as oleuropein, hydroxytyrosol, or tyrosol, possess antioxidant, anti-inflammatory, antiatherosclerotic, anti-ischemic, and hypolipidemic effects on the myocardium as demonstrated by various in vitro and in vivo studies. In this review article, we summarize the current knowledge on the role of the olive leaf constituents in the prevention of cardiac dysfunction and highlight future perspectives in their use as cardioprotective agents in therapeutics.

The natural olive constituent oleuropein induces nutritional cardioprotection in normal and cholesterol-fed rabbits: comparison with preconditioning

Ischemic preconditioning, which is mediated by cell signaling molecules, protects the heart from ischemia-reperfusion injury by limiting the infarct size. Oleuropein, the main polyphenolic constituent of olives, reduced the infarct size in normal and cholesterol-fed rabbits when it was administered at a nutritional dose. The aim of the present study was to compare the effects of oleuropein and preconditioning in terms of the cell signaling and metabolism pathways underlying myocardial protection. Rabbits were randomly divided into six groups: the control group received 5 % dextrose for six weeks, the preconditioning group was subjected to two cycles of preconditioning with 5 min ischemia/10 min reperfusion, the O6 group was treated with oleuropein for six weeks, the Chol group was fed a cholesterol-enriched diet and 5 % dextrose for six weeks, and the CholO6 and CholO3 groups were treated with cholesterol and oleuropein for six and three weeks, respectively; oleuropein was dissolved in 5 % dextrose solution and was administered orally at a dose of 20 mg × kg(-1) × day(-1). All animals were subsequently subjected to 30 min myocardial ischemia followed by 10 min of reperfusion. At that time, myocardial biopsies were taken from the ischemic areas for the assessment of oxidative and nitrosative stress biomarkers (malondialdehyde and nitrotyrosine), and determination of phosphorylation of signaling molecules involved in the mechanism of preconditioning (PI3K, Akt, eNOS, AMPK, STAT3). The tissue extracts NMR metabolic profile was recorded and further analyzed by multivariate statistics. Oxidative biomarkers were significantly reduced in the O6, CholO6, and CholO3 groups compared to the control, preconditioning, and Chol groups. Considering the underlying signaling cascade, the phosphorylation of PI3K, Akt, eNOS, AMPK, and STAT-3 was significantly higher in the preconditioning and all oleuropein-treated groups compared to the control and Chol groups. The NMR-based metabonomic study, performed through the analysis of spectroscopic data, depicted differences in the metabolome of the various groups with significant alterations in purine metabolism. In conclusion, the addition of oleuropein to a normal or hypercholesterolemic diet results in a preconditioning-like intracellular effect, eliminating the deleterious consequences of ischemia and hypercholesterolemia, followed by a decrease of oxidative stress biomarkers. This effect is exerted through inducing preconditioning-involved signaling transduction. Nutritional preconditioning may support the low cardiovascular morbidity and mortality associated with the consumption of olive products.

Cardioprotection by H2S engages a cGMP-dependent protein kinase G/phospholamban pathway

AIMS

H2S is known to confer cardioprotection; however, the pathways mediating its effects in vivo remain incompletely understood. The purpose of the present study is to evaluate the contribution of cGMP-regulated pathways in the infarct-limiting effect of H2S in vivo.

METHODS AND RESULTS

Anaesthetized rabbits were subjected to myocardial ischaemia (I)/reperfusion (R), and infarct size was determined in control or H2S-exposed groups. The H2S donor sodium hydrosulfide (NaHS, an agent that generates H2S) increased cardiac cGMP and reduced the infarct size. The cGMP-dependent protein kinase (PKG)-I inhibitor DT2 abrogated the protective effect of NaHS, whereas the control peptide TAT or l-nitroarginine methyl ester (l-NAME) did not alter the effect of NaHS. Moreover, the KATP channel inhibitor, glibenclamide, partially reversed the effects of NaHS, whereas inhibition of mitochondrial KATP did not modify the NaHS response. NaHS enhanced phosphorylation of phospholamban (PLN), in a PKG-dependent manner. To further investigate the role of PLN in H2S-mediated cardioprotection, wild-type and PLN KO mice underwent I/R. NaHS did not exert cardioprotection in PLN KO mice. Unlike what was observed in rabbits, genetic or pharmacological inhibition of eNOS abolished the infarct-limiting effect of NaHS in mice.

CONCLUSIONS

Our findings demonstrate (i) that administration of NaHS induces cardioprotection via a cGMP/PKG/PLN pathway and (ii) contribution of nitric oxide to the H2S response is species-specific.

Epicardial Fat in Nonalcoholic Fatty Liver Disease: Properties and Relationships With Metabolic Factors, Cardiac Structure, and Cardiac Function

Nonalcoholic fatty liver disease (NAFLD) is closely related to insulin resistance and the metabolic syndrome and might be an important cardiovascular (CV) risk factor. Epicardial adipose tissue (EAT) has been implicated in the pathogenesis of obesity-related CV disease. In an NAFLD population, we investigated EAT thickness and its possible relations to NAFLD and cardiac structure and function. This was an observational study of 57 patients with NAFLD and 48 age-matched controls. Patients with NAFLD had significantly higher body mass index (P < .0001), waist circumference (P < .0001), and high-sensitivity C-reactive protein (P = .005), whereas high-density lipoprotein cholesterol (P = .01) and adiponectin (P = .005) levels were significantly lower. The EAT was not thicker in NAFLD but was positively related to indices of impaired glucose tolerance and inflammation, with diabetes being an independent predictor of EAT thickness (b* = 0.29, P = .04). No relations were found between EAT and cardiac structure and function. In conclusion, this study confirms a pathologic phenotype of NAFLD. Epicardial fat was not significantly related to NAFLD per se, but diabetes, glucose metabolism, and inflammation were closely related to its thickness.