AIM:Myocardial infarction (MI) is one of the leading causes of death worldwide. MI is associated with cardiac structural and functional alterations. Among these, cardiac fibrosis may be significantly influenced by mitochondrial dysfunction. We sought to evaluate whether the injection of functional mitochondria from healthy muscle could improve the detrimental consequences of MI. METHODS:Male Wistar rats were submitted to MI through the ligature of the left anterior descending coronary artery. Animals subjected to a sham operation (the same surgical procedure without fastening of the suture that passes through the LAD) were included as a reference group (Sham). At the time of surgery, either vehicle (PBS) or isolated mitochondria (equivalent to 180 μg of mitochondrial protein in 75 μL of vehicle) were directly injected into the myocardium around the ligation to half of the animals in each group. Animals were sacrificed 4 weeks after both MI induction and the evaluation of cardiac and systolic functions. RESULTS:Cardiac mitochondrial transplantation was able to prevent the decrease in systolic function and the development of cardiac fibrosis in MI rats. These beneficial effects were accompanied by a reduction in cardiac hypertrophy, oxidative stress, endoplasmic reticulum stress activation, and inflammatory markers. We also evaluated the effects of mitochondrial transplantation by a proteomic analysis. In addition, cardiac mitochondrial transplantation was able to prevent the development of renal alterations observed in MI rats. CONCLUSIONS:The data reveal novel mechanisms of mitochondrial transplantation effects and emerge as a novel therapeutic strategy under chronic diseases such as MI.

Abstract Aim Left atrial (LA) function is linked with clinical events in different cardiovascular scenarios. Our aim was to evaluate the associated between LA function and different imaging and serological biomarkers in a cohort of patients with a first episode of acute myocardial infarction (AMI). Methods Prospective cohort of patients with a first episode of AMI treated with percutaneous revascularization in a tertiary care hospital in 2016. All patients underwent echocardiography and cardiac magnetic resonance and blood samples were taken for serological biomarkers analysis. LA function was assessed by means of LA stiffness (E/e’ divided by LA reservoir strain) and LA volumetric-mechanical coupling index [LACI] (LA volume index divided by tissue Doppler a’). Results Mean age of patients in our cohort (n=41) was 57.5±10 years, and 38 (93%) were male. 64% of patients had single vessel coronary artery disease, and median LVEF eas 58% (55-62). Regarding LA function, median LACI was 2.47 (1.99-3.14) and median LA stiffness was 0.27 (0.21-0.44), with 11 (26.8%) patients fulfilling criteria for high LA stiffness. The correlation between these parameters and different imaging and serological biomarkers is shown in Figure 1. There was a significant correlation between LA stiffness and ventricular-arterial coupling, infarct size, and T1 native values. LACI was associated with pulmonary artery systolic pressure, interleukin-6 and soluble CD-14 antigen. Both LA parameters were also significantly associated with left ventricular (LV) ejection fraction and LV global longitudinal strain (Figure 2). Conclusions In our cohort of patients with a first episode of AMI, echocardiographic parameters of LA function were significantly associated with LV function, infarct size and serological biomarkers of inflammation. These parameters might serve as an additional tool for risk stratification in patients with ischemic cardiomyopathy. Figure 1 Figure 2

Cardiovascular disease (CVD) is the main cause of death worldwide, with myocardial infarction (MI) being the most prevalent pathology involved in CVD. MI is characterized by a deficiency in oxygen supply to the myocardium, thereby promoting ventricular remodeling of the ischemic and remote zone of the heart. Cardiac remodeling associated with MI could promote the development of heart failure and finally death. For these reasons, it is important to develop animal models that mimic human cardiac disease which could help to identify new mechanisms involved in the pathology and, consequently, develop new therapeutic strategies. We herein describe in detail a protocol for MI induction with low mortality rate (<15%) in rats by ligation of the left anterior descending artery. In addition, we also describe two imaging techniques which allow to evaluate cardiac structure and function-including deformation parameters in rats such as transthoracic echocardiography and cardiac magnetic resonance. This animal model could be useful for acute and chronic studies and for evaluating the potential usefulness of different treatments.

Background Modified citrus pectin (MCP) is used as a nutritional supplement that inhibits galectin-3 activity, a central player in the cardiac damage associated with different pathological situations. In fact, we have previously observed that MCP improved cardiac function in obese infarcted rats that was associated with a reduction in cardiac fibrosis. Therefore, the aim of the present study was to further explore whether this effect could involve the modulation of gene expression of ECM components and their mediators as well as whether it could affect another two mechanisms involved in cardiac damage: mitochondrial dynamics and autophagic flux. Methods Male Wistar rats were fed an atherogenic diet with a high content of saturated fat (35%). MI was induced by the ligation of left anterior descendant (LAD) coronary artery 6 weeks after and MCP (100mg/kg/day) or vehicle were administered for 4 weeks more. A group of rats fed a standard diet (5.3% fat) and subjected to a sham operation was used as controls. Results Obese infarcted animals presented an increase in cross-linked collagen that was not affected by the administration of galectin-3 inhibitor. However, MCP reduced the increase in gene expression observed in obese infarcted rats of ECM components and mediators (collagen I, fibronectin, transforming growth factor-β and connective tissue growth factor), of components of endoplasmic reticulum stress (binding immunoglobulin protein, CCAAT-enhancer-binding homologous protein and activating transcription factor 4), of oxidative stress mediator (NADPH oxidase-4) and normalized those of the interleukin 33/ST2 system. MCP is also able to increase the levels of the mitochondrial protein Dynamin-1-like and those of both proteins involved in autophagic flux (p62 and LC3) that were reduced by the myocardial ischemia in the context of obesity. Conclusions The data show that the beneficial effect of the nutritional supplement MCP on the cardiac consequences associated with myocardial ischemia in the context of obesity could rely on its capacity to inhibit galectin-3 and to consequently modulate different downstream mechanisms, including inflammation, ER stress, oxidative stress, autophagy and mitochondrial function, which can facilitate fibrosis and cardiac remodeling in this pathological context.

The association between cardiac fibrosis and galectin-3 was evaluated in patients with acute myocardial infarction (MI). The role of galectin-3 and its association with endoplasmic reticulum (ER) stress activation in the progression of cardiovascular fibrosis was also evaluated in obese-infarcted rats. The inhibitor of galectin-3 activity, modified citrus pectin (MCP; 100 mg/kg/day), and the inhibitor of the ER stress activation, 4-phenylbutyric acid (4-PBA; 500 mg/kg/day), were administered for 4 weeks after MI in obese rats. Overweight-obese patients who suffered a first MI showed higher circulating galectin-3 levels, higher extracellular volume, and LV infarcted size, as well as lower E/e'ratio and LVEF compared with normal-weight patients. A correlation was observed between galectin-3 levels and extracellular volume. Obese-infarcted animals presented cardiac hypertrophy and reduction in LVEF, and E/A ratio as compared with control animals. They also showed an increase in galectin-3 gene expression, as well as cardiac fibrosis and reduced autophagic flux. These alterations were associated with ER stress activation characterized by enhanced cardiac levels of binding immunoglobulin protein, which were correlated with those of galectin-3. Both MCP and 4-PBA not only reduced cardiac fibrosis, oxidative stress, galectin-3 levels, and ER stress activation, but also prevented cardiac functional alterations and ameliorated autophagic flux. These results show the relevant role of galectin-3 in the development of diffuse fibrosis associated with MI in the context of obesity in both the animal model and patients. Galectin-3 in tandem with ER stress activation could modulate different downstream mechanisms, including inflammation, oxidative stress, and autophagy.

During resolution of inflammation, specialized proresolving mediators (SPMs), including resolvins, are produced to restore tissue homeostasis. We hypothesized that there might be a dysregulation of SPMs pathways in pathological vascular remodeling and that resolvin D2 (RvD2) might prevent vascular remodeling and contractile and endothelial dysfunction in a model of obesity and hypertension. In aortic samples of patients with or without abdominal aortic aneurysms (AAA), we evaluated gene expression of enzymes involved in SPMs synthesis (ALOXs), SPMs receptors and pro-inflammatory genes. In an experimental model of aortic dilation induced by high fat diet (HFD, 60%, eighteen weeks) and angiotensin II (AngII) infusion (four weeks), we studied the effect of RvD2 administration in aorta and small mesenteric arteries structure and function and markers of inflammation. In human macrophages we evaluated the effects of AngII and RvD2 in macrophages function and SPMs profile. In patients, we found positive correlations between AAA and obesity, and between AAA and expression of ALOX15, RvD2 receptor GPR18, and pro-inflammatory genes. There was an inverse correlation between the expression of aortic ALOX15 and AAA growth rate. In the mice model, RvD2 partially prevented the HFD plus AngII-induced obesity and adipose tissue inflammation, hypertension, aortic and mesenteric arteries remodeling, hypercontratility and endothelial dysfunction, and the expression of vascular proinflammatory markers and cell apoptosis. In human macrophages, RvD2 prevented AngII-induced impaired efferocytosis and switched SPMs profile. RvD2 might represent a novel protective strategy in preventing vascular damage associated to hypertension and obesity likely through effects in vascular and immune cells.

M. Hernández-Martín1M.D. Vicente-Torres2L. Rivera1D. Prieto1S. Benedito1N. De las Heras2A. López-Calderón2J.A. García-Donaire3M. Abad-Cardiel3N. Martell3R. Redondo-Castillejo1S.D. Paredes2D. Gómez-Garre2J.A. Issa1M.P. Montenegro1C. Contreras1V. Azcutia1M.C. Lozano-Estevan 4V. Hurtado-Carneiro2R. Rodrígues-Díez2A.I. Martín-Velasco2F. Das Chagas Vasconcelos2G. Segovia2T. Priego2R. Gredilla2V. Cachofeiro2M.V. Hernández1A. Agis-Torres1P. Recio1M. Muñoz-Picos1J. Navarro-Dorado1N.F. Pascual1B. Colino1A. Gómez Del Val1I. Rodríguez-Ramiro4R. Raposo1C. Soriano1M. Sancho2V.S. Leite1J.M. Bravo2J.A. García-Baró2E. Martínez-Martínez2A. Moreno2E. Nebot2A. Sánchez-Aguilera2A. Sánchez-Pina1M.E. López-Oliva 5

M. Hernández Martín1A. Sánchez-Pina1R. Redondo-Castillejo1J.A. Issa1M.A. Vicente-Torres2S.D. Paredes2N. de las Heras2A. López-Calderón2G. Segovia2V. Azcutia1V. Hurtado2A.I. Martín-Velasco2C. Contreras1T. Priego2D. Gómez-Garre2M.P. Montenegro1P. Recio1I. Rodriguez-Ramiro1V. Cachofeiro2A. Gómez del Val1M. Muñoz-Picos1J. Navarro-Dorado 1N.F. Pascual1B. Colino1V.S. Leite1A. Agis-Torres1R. Raposo1J.M. Bravo2A. Sanchez-Aguilera2M. Sancho2E. Martinez-Martinez2E. Nebot2R. Rodrígues-Díez2R. Rodríguez-Diez2P. Vázquez1M. Hernández1F. Das Chagas Vasconcelos2R. Gredilla2G. Giorgi1N. Martell3M. Abad3J.A. García-Donaire3D. Prieto1S. Benedito1L. Rivera1M.E. Lopez-Oliva1

A.A. Sánchez-PinaA. Agis-TorresS. BeneditoC. ContrerasA. Gómez Del ValM. Hernández-MartínM.V. HernándezJ.A. IsaaV.S. Leite FernandesM.P. MontenegroM. Muñoz-PicosJ. Navarro-DoradoN.F. PascualD. PrietoR. RaposoP. RecioR. Redondo-CastillejoL. RiveraJ.M. BravoV. CachofeiroJ.A. García BaróD. Gómez GarreR. GredillaN. de las HerasV. Hurtado-CarneiroA. López-CalderónA.I. Martín VelascoE. Martínez-MartínezA. Moreno-RupérezE. NebotS.D. ParedesT. PriegoR. Rodrígues-DíezA. Sánchez-AguileraM. SanchoG. SegoviaF. Das Chagas VasconcelosM.A. Vicente-TorresM.E. López-Oliva

BackgroundOver the past years, information about the crosstalk between the epicardial adipose tissue (EAT) and the cardiovascular system has emerged. Notably, in the context of acute myocardial infarction (AMI), EAT might have a potential role in the pathophysiology of ventricular structural changes and function, and the clinical evolution of patients. This study aims to assess the impact of EAT on morpho-functional changes in the left ventricle (LV) and the outcome of patients after an AMI.MethodsWe studied prospectively admitted patients to our hospital with a first episode of AMI. All patients underwent percutaneous coronary intervention (PCI) during admission. Transthoracic echocardiography (TTE) was performed within 24–48 h after PCI, as well as blood samples to assess levels of galectin-3 (Gal-3). Cardiac magnetic resonance (CMR) was performed 5–7 days after PCI. Clinical follow-up was performed at 1 and 5 years after MI.ResultsMean age of our cohort (n = 41) was 57.5 ± 10 years, and 38 (93%) were male. Nine patients had normal BMI, 15 had overweight (BMI 25–30), and 17 were obese (BMI > 30). Twenty three patients (56%) had ≥ 4 mm thickness of EAT measured with echo. In these patients, baseline left ventricular ejection fraction (LVEF) after AMI was significantly lower, as well as global longitudinal strain. EAT thickness ≥ 4 m patients presented larger infarct size, higher extracellular volume, and higher T1 times than patients with EAT < 4 mm. As for Gal-3, the median was 16.5 ng/mL [12.7–25.2]. At five-year follow-up 5 patients had major cardiac events, and all of them had EAT ≥ 4 mm.ConclusionsPatients with EAT >4 mm have worse LVEF and GLS, larger infarct size and longer T1 values after a MI, and higher levels of Gal-3. EAT >4 mm was an independent predictor of MACE at 5-year follow-up. EAT thickness is a feasible, noninvasive, low-cost parameter that might provide important information regarding the chronic inflammatory process in the myocardium after an infarction.

A proteomic approach was used to characterize potential mediators involved in the improvement in cardiac fibrosis observed with the administration of the mitochondrial antioxidant MitoQ in obese rats. Male Wistar rats were fed a standard diet (3.5% fat; CT) or a high-fat diet (35% fat; HFD) and treated with vehicle or MitoQ (200 μM) in drinking water for 7 weeks. Obesity modulated the expression of 33 proteins as compared with controls of the more than 1000 proteins identified. These include proteins related to endoplasmic reticulum (ER) stress and oxidative stress. Proteomic analyses revealed that HFD animals presented with an increase in cardiac transthyretin (TTR) protein levels, an effect that was prevented by MitoQ treatment in obese animals. This was confirmed by plasma levels, which were associated with those of cardiac levels of both binding immunoglobulin protein (BiP), a marker of ER stress, and fibrosis. TTR stimulated collagen I production and BiP in cardiac fibroblasts. This upregulation was prevented by the presence of MitoQ. In summary, the results suggest a role of TTR in cardiac fibrosis development associated with obesity and the beneficial effects of treatment with mitochondrial antioxidants.

BACKGROUND AND PURPOSE:Microsomal prostaglandin E synthase-1 (mPGES-1) is an inducible isomerase responsible for prostaglandin E2 production in inflammatory conditions. We evaluated the role of mPGES-1 in the development and the metabolic and cardiovascular alterations of obesity.EXPERIMENTAL APPROACH:mPGES-1+/+ and mPGES-1-/- mice were fed with normal or high fat diet (HFD, 60% fat). The glycaemic and lipid profile was evaluated by glucose and insulin tolerance tests and colorimetric assays. Vascular function, structure and mechanics were assessed by myography. Histological studies, q-RT-PCR, and western blot analyses were performed in adipose tissue depots and cardiovascular tissues. Gene expression in abdominal fat and perivascular adipose tissue (PVAT) from patients was correlated with vascular damage.KEY RESULTS:Male mPGES-1-/- mice fed with HFD were protected against body weight gain and showed reduced adiposity, better glucose tolerance and insulin sensitivity, lipid levels and less white adipose tissue and PVAT inflammation and fibrosis, compared with mPGES-1+/+ mice. mPGES-1 knockdown prevented cardiomyocyte hypertrophy, cardiac fibrosis, endothelial dysfunction, aortic insulin resistance, and vascular inflammation and remodelling, induced by HFD. Obesity-induced weight gain and endothelial dysfunction of resistance arteries were ameliorated in female mPGES-1-/- mice. In humans, we found a positive correlation between mPGES-1 expression in abdominal fat and vascular remodelling, vessel stiffness, and systolic blood pressure. In human PVAT, there was a positive correlation between mPGES-1 expression and inflammatory markers.CONCLUSIONS AND IMPLICATIONS:mPGES-1 inhibition might be a novel therapeutic approach to the management of obesity and the associated cardiovascular and metabolic alterations.