Atrial matrix remodeling in atrial fibrillation patients with aortic stenosis.

BACKGROUND: This study aimed to evaluate atrium extracellular matrix remodeling in atrial fibrillation (AF) patients with severe aortic stenosis, through histological fibrosis quantification and extracellular matrix gene expression analysis, as well as serum quantification of selected protein targets. METHODS: A posthoc analysis of a prospective study was performed in a cohort of aortic stenosis patients. Between 2014 and 2019, 56 patients with severe aortic stenosis submitted to aortic valve replacement surgery in a tertiary hospital were selected. RESULTS: Fibrosis was significantly increased in the AF group when compared to sinus rhythm (SR) patients (p = 0.024). Moreover, cardiomyocyte area was significantly higher in AF patients versus SR patients (p = 0.008). Conversely, collagen III gene expression was increased in AF patients (p = 0.038). TIMP1 was less expressed in the atria of AF patients. MMP16/TIMP4 ratio was significantly decreased in AF patients (p = 0.006). TIMP1 (p = 0.004) and TIMP2 (p = 0.012) were significantly increased in the serum of AF patients. Aortic valve maximum (p = 0.0159) and mean (p = 0.031) gradients demonstrated a negative association with serum TIMP1. CONCLUSIONS: Atrial fibrillation patients with severe aortic stenosis present increased atrial fibrosis and collagen type III synthesis, with extracellular matrix remodelling demonstrated by a decrease in the MMP16/TIMP4 ratio, along with an increased serum TIMP1 and TIMP2 proteins.

Modulation of iris sphincter and ciliary muscles by urocortin 2.

Urocortin 2 (UCN2) is a peptide related to corticotropin-releasing factor, capable of activating CRF-R2. Among its multisystemic effects, it has actions in all 3 muscle subtypes. This study's aim was to determine its potential role in two of the intrinsic eye muscle kinetics. Strips of iris sphincter (rabbit) and ciliary (bovine) muscles were dissected and mounted in isometric force-transducer systems filled with aerated-solutions. Contraction was elicited using carbachol (10(-6) M for iris sphincter, 10(-5) M for ciliary muscle), prior adding to all testing substances. UCN2 induced relaxation in iris sphincter muscle, being the effect maximal at 10(-7) M concentrations (-12.2 % variation vs. control). This effect was abolished with incubation of indomethacin, antisauvagine-30, chelerytrine and SQ22536, but preserved with L-nitro-L-arginine. In carbachol pre-stimulated ciliary muscle, UCN2 (10(-5) M) enhanced contraction (maximal effect of 18.2 % increase vs. control). UCN2 is a new modulator of iris sphincter relaxation, dependent of CRF-R2 activation, synthesis of prostaglandins (COX pathway) and both adenylate cyclase and PKC signaling pathways, but independent of nitric oxide production. Regarding ciliary muscle, UCN2 enhances carbachol-induced contraction, in higher doses.

A Critical Analysis of the Available In Vitro and Ex Vivo Methods to Study Retinal Angiogenesis.

Angiogenesis is a biological process with a central role in retinal diseases. The choice of the ideal method to study angiogenesis, particularly in the retina, remains a problem. Angiogenesis can be assessed through in vitro and in vivo studies. In spite of inherent limitations, in vitro studies are faster, easier to perform and quantify, and typically less expensive and allow the study of isolated angiogenesis steps. We performed a systematic review of PubMed searching for original articles that applied in vitro or ex vivo angiogenic retinal assays until May 2017, presenting the available assays and discussing their applicability, advantages, and disadvantages. Most of the studies evaluated migration, proliferation, and tube formation of endothelial cells in response to inhibitory or stimulatory compounds. Other aspects of angiogenesis were studied by assessing cell permeability, adhesion, or apoptosis, as well as by implementing organotypic models of the retina. Emphasis is placed on how the methods are applied and how they can contribute to retinal angiogenesis comprehension. We also discuss how to choose the best cell culture to implement these methods. When applied together, in vitro and ex vivo studies constitute a powerful tool to improve retinal angiogenesis knowledge. This review provides support for researchers to better select the most suitable protocols in this field.

Frailty Syndrome: Visceral Adipose Tissue and Frailty in Patients with Symptomatic Severe Aortic Stenosis.

BACKGROUND/OBJECTIVES: In patients with severe aortic stenosis (AS), frailty is a clinically relevant measure of increased vulnerability that should be included in the preoperative risk assessment. Bioelectrical impedance analysis (BIA) derived phase angle (PA) reflects cell membrane integrity and function. Few studies are available on the relative contribution of adiposity distribution on frailty, and about the influences of frailty and visceral obesity in PA value. Therefore, we aimed to evaluate associations among frailty, visceral fat depots and PA in patients with symptomatic severe AS. METHODS: In a cohort of patients with symptomatic severe AS and preserved ejection fraction, we examined the associations between frailty, visceral fat depots and bioelectrical impedance analysis (BIA) derived phase angle (PA); and between visceral fat and PA. Frailty was defined according the Fried et al. scale criteria and the body fat distribution was determined by multidetector computed tomography and by BIA. RESULTS: Of the fifty-five included patients, 26 were frail (47%). Adjusting for age and gender, frailty was associated with indexed epicardial adipose tissue volume (EATVi) (the odds of frailty increased 4.1-fold per additional 100 cm3/m2 of EAT [95% confidence interval (CI) of 1.03 to 16.40, p=0.04] and with PA (OR of 0.50, 95% CI, 0.26 to 0.97, p=0.04), but not with body mass index (BMI), waist circumference (WC), indexed total, visceral and subcutaneous abdominal fat areas (TAFAi, VAFAi and SAFAi) nor with indexed mediastinal adipose tissue volume (MATVi). In an age and gender adjusted linear model, PA was inversely correlated with EATVi (ß=-0.008, 95% CI, -0.016 to -0.001, p=0.03), but not with BMI, WC, nor with MATVi, VAFAi, SAFAi and TAFAi. CONCLUSIONS: In patients with symptomatic severe AS, EATVi is associated with frailty, independently of age and gender, but not with MAFVi or VAFAi. Moreover, frailty and EATVi are associated with impaired cell membrane integrity and function assessed by PA.

Worse cardiac remodeling in response to pressure overload in type 2 diabetes mellitus.

BACKGROUND: Diabetic cardiomyopathy is characterized by cardiac structural and functional abnormalities. Additionally, chronic pressure overload conditions are highly prevalent amongst diabetic population and this association leads to a more severe myocardial impairment. The differences in myocardial pathophysiology between type 1 and type 2 diabetes mellitus (DM) still remain to be clarified. Thus, we aimed to investigate biventricular structural and functional changes promoted by the two types of DM and the impact of concomitant chronic pressure overload. METHODS: Wistar rats were injected with streptozotocin (Type 1 DM, T1DM) or fed with a hypercaloric diet (Type 2 DM, T2DM). Pressure overload was imposed in DM animals by aortic constriction and after 5weeks of DM the cardiac function and structure were evaluated. RESULTS: Both types of DM promoted hypertrophy, increased fibrosis and advanced glycation end-products deposition, in the two ventricles. Interestingly, the induced myocardial alterations were distinct. While T1DM stimulated a pronounced hypertrophy and extracellular matrix remodeling, T2DM induced functional impairment. The negative impact of the association of DM with aortic constriction was more pronounced in T2DM, promoting impaired function and increased stiffness, particularly in the right ventricle. CONCLUSIONS: Our study demonstrated that the two types of diabetes induce distinct cardiac alterations per se or when combined with chronic pressure overload. T1DM promoted a more extensive remodeling in cardiac structure while T2DM significantly impaired ventricular function. The impact of pressure overload was more notorious in T2DM as observed by worse myocardial remodeling, suggesting a higher susceptibility to the deleterious effects of chronic pressure overload, namely hypertension, among this diabetic population.

Distinct right ventricle remodeling in response to pressure overload in the rat.

Pulmonary arterial hypertension (PAH), the most serious chronic disorder of the pulmonary circulation, is characterized by pulmonary vasoconstriction and remodeling, resulting in increased afterload on the right ventricle (RV). In fact, RV function is the main determinant of prognosis in PAH. The most frequently used experimental models of PAH include monocrotaline- and chronic hypoxia-induced PAH, which primarily affect the pulmonary circulation. Alternatively, pulmonary artery banding (PAB) can be performed to achieve RV overload without affecting the pulmonary vasculature, allowing researchers to determine the RV-specific effects of their drugs/interventions. In this work, using two different degrees of pulmonary artery constriction, we characterize, in full detail, PAB-induced adaptive and maladaptive remodeling of the RV at 3 wk after PAB surgery. Our results show that application of a mild constriction resulted in adaptive hypertrophy of the RV, with preserved systolic and diastolic function, while application of a severe constriction resulted in maladaptive hypertrophy, with chamber dilation and systolic and diastolic dysfunction up to the isolated cardiomyocyte level. By applying two different degrees of constriction, we describe, for the first time, a reliable and short-duration PAB model in which RV adaptation can be distinguished at 3 wk after surgery. We characterize, in full detail, structural and functional changes of the RV in its response to moderate and severe constriction, allowing researchers to better study RV physiology and transition to dysfunction and failure, as well as to determine the effects of new therapies.

Calreticulin in the Heart: From Embryological Development to Cardiac Pathology.

BACKGROUND: Calreticulin is a Ca(2+)-binding chaperone in the endoplasmic reticulum (ER) which is crucial to the correct embryological development of the heart in mice. Altered expression levels in the adult were correlated with several cardiac pathologies such as cardiac hypertrophy and dilated cardiomyopathy. AIM: In this review, we aim to describe the role of calreticulin in the embryological development of the heart in mice and to clarify the relationship between the different cardiac pathologies and altered expression levels of calreticulin in the adult heart. CONCLUSION: There is an ER crucial to embryogenesis in cardiomyocytes besides SR. Certain stimuli may induce reactivation of the transcription pattern present during embryogenesis, leading to overexpression of calreticulin in the heart, altering numerous signaling pathways and subsequently inducing pathology. Normalization of these transcriptional disorders holds promise in the treatment of multiple cardiac diseases.

S100A1: a major player in cardiovascular performance.

Calcium cycling is a major determinant of cardiac function. S100A1 is the most abundant member of the calcium-binding S100 protein family in myocardial tissue. S100A1 interacts with a variety of calcium regulatory proteins such as SERCA2a, ryanodine receptors, L-type calcium channels and Na(+)/Ca(2+) exchangers, thus enhancing calcium cycling. Aside from this major function, S100A1 has an important role in energy balance, myofilament sliding, myofilament calcium sensibility, titin-actin interaction, apoptosis and cardiac remodeling. Apart from its properties regarding cardiomyocytes, S100A1 is also important in vessel relaxation and angiogenesis. S100A1 potentiates cardiac function thus increasing the cardiomyocytes' functional reserve; this is an important feature in heart failure. In fact, S100A1 seems to normalize cardiac function after myocardial infarction. Also, S100A1 is essential in the acute response to adrenergic stimulation. Gene therapy experiments show promising results, although further studies are still needed to reach clinical practice. In this review, we aim to describe the molecular basis and regulatory function of S100A1, exploring its interactions with a myriad of target proteins. We also explore its functional effects on systolic and diastolic function as well as its acute actions. Finally, we discuss S100A1 gene therapy and its progression so far.

Identification of the ghrelin-GHSR 1 system and its influence in the modulation of induced ocular hypertension in rabbit and rat eyes.

Recent studies evidenced a decrease in ghrelin's aqueous humor levels in patients with glaucoma. The goal of our investigation was to study the effect of the ghrelin-GHSR-1a system in the modulation of intraocular pressure in acute ocular hypertension models and its expression and distribution in ocular tissues. Two animal models of acute ocular hypertension were used to study the effect of the ghrelin-GHSR-1a system in the modulation of intraocular pressure: the rabbit and the rat. Ocular hypertension was induced by an intravitreal injection of 20% NaCl. Ghrelin or des-acyl ghrelin were delivered subconjunctivally and the intraocular pressure was assessed by a rebound tonometer that was calibrated for each species. In addition, we have studied the influence of nitric oxide and prostaglandins on ghrelin's effect in the rabbit animal model. Finally, we determined by immunofluorescence the expression of ghrelin and GHSR-1 in the rat's ocular tissue. Ghrelin decreased the intraocular pressure in both animal models (maximum decrease: 43.8±12.0% in the rabbit and 29.0±7.46% in the rat). In the rabbit, this effect was blunted in the presence of l-NAME and ketorolac. Des-acyl ghrelin only decreased the intraocular pressure in the rat (maximum decrease: 34.9±8.15%). Ghrelin expression was detected in the ciliary processes and GHSR-1 expression was detected in the trabecular meshwork and ciliary body. The ghrelin-GHSR-1 system is expressed in the anterior segment of the eye. Ghrelin and des-acyl ghrelin are responsible for a hypotensive effect in acute ocular hypertension animal models.

Establishment of heart teams in Portugal.

Whenever several therapeutic options exist, multidisciplinary decision-making is beneficial for the patient and for society at large. The main obstacles to the establishment of heart teams in Portugal are organizational and logistical. Implementing a heart team approach entails definition of the situations requiring multidisciplinary discussion, creation of clear lines of communication, written protocols and obtaining patient informed consent. The European Society of Cardiology guidelines define the clinical scenarios where intervention of the heart team is recommended.

Intraventricular pressure gradients in heart failure.

The aim of the present study was to characterize intraventricular pressure gradients (IVPGs) in an animal model of chronic heart failure. New Zealand rabbits were treated with doxorubicin (heart failure group, n=5) or saline (control group, n=5) and instrumented with pressure catheters placed in the apex and outflow-tract of left ventricle (LV) and with sonomicrometer crystals placed in the apex and base of the LV free wall. In heart failure animals, ventricular filling was delayed and slower when compared with control animals. Moreover, the physiological nonuniformity observed between apical and basal segments in normal hearts was abolished in failing hearts. Simultaneously, physiological IVPGs observed during normal ventricular filling were entirely lost in heart failure animals. During ventricular emptying physiological nonuniformity between apical and basal segments observed in control animals was also abolished in heart failure animals. In failing hearts minimal length occurred later and almost at same time both in apical and in basal myocardial segments. Simultaneously, the characteristic IVPG pattern observed in healthy hearts during systole, which promotes ventricular emptying, was not observed in failing hearts. The present study showed that diastolic IVPGs, a marker of normal ventricular filling, and systolic IVPGs, a marker of normal ventricular emptying, are abolished in heart failure.

Synergistic impact of endurance training and intermittent hypobaric hypoxia on cardiac function and mitochondrial energetic and signaling.

BACKGROUND: Intermittent hypobaric-hypoxia (IHH) and endurance-training (ET) are cardioprotective strategies against stress-stimuli. Mitochondrial modulation appears to be an important step of the process. This study aimed to analyze whether a combination of these approaches provides additive or synergistic effects improving heart-mitochondrial and cardiac-function. METHODS: Two-sets of rats were divided into normoxic-sedentary (NS), normoxic-exercised (NE, 1 h/day/5 weeks treadmill-running), hypoxic-sedentary (HS, 6000 m, 5h/day/5 weeks) and hypoxic-exercised (HE) to study overall cardiac and mitochondrial function. In vitro cardiac mitochondrial oxygen consumption and transmembrane potential were evaluated. OXPHOS subunits and ANT protein content were semi-quantified by Western blotting. HIF-1α, VEGF, VEGF-R1 VEGF-R2, BNP, SERCA2a and PLB expressions were measured by qRT-PCR and cardiac function was characterized by echocardiography and hemodynamic parameters. RESULTS: Respiratory control ratio (RCR) increased in NE, HS and HE vs. NS. Susceptibility to anoxia/reoxygenation-induced dysfunction decreased in NE, HS and HE vs. NS. HS decreased mitochondrial complex-I and -II subunits; however HE completely reverted the decreased content in complex-II subunits. ANT increased in HE. HE presented normalized ventricular-arterial coupling (Ea) and BNP myocardial levels and significantly improved myocardial performance as evaluated by increased cardiac output and normalization of the Tei index vs. HS CONCLUSION: Data demonstrates that IHH and ET confer cardiac mitochondria with a more resistant phenotype although without visible addictive effects at least under basal conditions. It is suggested that the combination of both strategies, although not additive, results into improved cardiac function.

New therapeutic targets for intraocular pressure lowering.

Primary open-angle glaucoma (POAG) is a leading cause of irreversible and preventable blindness and ocular hypertension is the strongest known risk factor. With current classes of drugs, management of the disease focuses on lowering intraocular pressure (IOP). Despite of their use to modify the course of the disease, none of the current medications for POAG is able to reduce the IOP by more than 25%-30%. Also, some glaucoma patients show disease progression despite of the therapeutics. This paper examines the new described physiological targets for reducing the IOP. The main cause of elevated IOP in POAG is thought to be an increased outflow resistance via the pressure-dependent trabecular outflow system, so there is a crescent interest in increasing trabecular meshwork outflow by extracellular matrix remodeling and/or by modulation of contractility/TM cytoskeleton disruption. Modulation of new agents that act mainly on trabecular meshwork outflow may be the future hypotensive treatment for glaucoma patients. There are also other agents in which modulation may decrease aqueous humour production or increase uveoscleral outflow by different mechanisms from those drugs available for glaucoma treatment. Recently, a role for the ghrelin-GHSR system in the pathophysiology modulation of the anterior segment, particularly regarding glaucoma, has been proposed.

[Conservative aortic valve surgery]. / Cirurgia conservadora da válvula aórtica.

Conservative aortic valve surgery is an attractive approach for the correction of the aortic insufficiency and the dilation of the aortic root. Despite being a surgery made in a minority of the patients it's receiving increased attention in the last decade because it can minimize the complications and risks that are inherent to the use of a mechanic or biologic valve. In the following article we propose ourselves to review the actual state of knowledge regarding conservative aortic valve surgery and the path that this type of surgical procedure must have in order to become the gold standard approach for the surgical correction of the aortic insufficiency or dilation of aortic root.

Rodent models of heart failure: an updated review.

Heart failure (HF) is one of the major health and economic burdens worldwide, and its prevalence is continuously increasing. The study of HF requires reliable animal models to study the chronic changes and pharmacologic interventions in myocardial structure and function and to follow its progression toward HF. Indeed, during the past 40 years, basic and translational scientists have used small animal models to understand the pathophysiology of HF and find more efficient ways of preventing and managing patients suffering from congestive HF (CHF). Each species and each animal model has advantages and disadvantages, and the choice of one model over another should take them into account for a good experimental design. The aim of this review is to describe and highlight the advantages and drawbacks of some commonly used HF rodents models, including both non-genetically and genetically engineered models, with a specific subchapter concerning diastolic HF models.

Epicardial adipose tissue is an independent predictor of coronary atherosclerotic burden.

INTRODUCTION: Epicardial adipose tissue (EAT) may play an active role in the development of coronary artery disease (CAD). The aim of this work was to study the relations between EAT, abdominal visceral fat (AVF), and coronary atherosclerotic burden as assessed by multislice computed tomography (MSCT). POPULATION AND METHODS: Two hundred fifteen patients without known CAD referred to 64-SCT during a 6-months period were included. All patients underwent a standardized protocol including quantification of AVF, EAT, coronary artery calcification (CAC), and coronary angiography by MSCT. RESULTS: Two hundred fifteen patients, with mean age of 58 ± 11 years, in which 61% were males, with mean body mass index (BMI) of 28 ± 4 kg/m(2) were included. EAT volume was directly associated with male sex, age, BMI, abdominal circumference, AVF, number of coronary segments with atherosclerotic plaques (p<0.01 for all), number of segments with significant stenoses, and presence of metabolic syndrome components (p<0.05). CAC increased by 14.7% per additional 10 ml of EAT volume. Adjusting for age, gender, and AVF changed this increase to 7.5%. After adjusting for all considered confounders, there was still an independent association, with a CAC increase of 3.7% per additional 10 ml of EAT. A significant interaction was found between EAT volume and gender and between EAT volume and obesity: an increase of EAT was associated with an increase of additional 8% of CAC in men, and additional increase of 5% in non-obese individuals (p<0.001 for both). CONCLUSION: EAT volume positively relates to coronary atherosclerotic burden, as assessed by CAC; this correlation was shown to be independent of AVF.

Modulation of myocardial stiffness by ß-adrenergic stimulation--its role in normal and failing heart.

The acute effects of beta-adrenergic stimulation on myocardial stiffness were evaluated. New-Zealand white rabbits were treated with saline (control group) or doxorubicin to induce heart failure (HF) (DOXO-HF group). Effects of isoprenaline (10(-10)-10(-5) M), a non-selective beta-adrenergic agonist, were tested in papillary muscles from both groups. In the control group, the effects of isoprenaline were also evaluated in the presence of a damaged endocardial endothelium, atenolol (beta(1)-adrenoceptor antagonist), ICI-118551 (beta(2)-adrenoceptor antagonist), KT-5720 (PKA inhibitor), L-NNA (NO-synthase inhibitor), or indomethacin (cyclooxygenase inhibitor). Passive length-tension relations were constructed before and after adding isoprenaline (10(-5) M). In the control group, isoprenaline increased resting muscle length up to 1.017+/-0.006 L/L(max). Correction of resting muscle length to its initial value resulted in a 28.5+/-3.1 % decrease of resting tension, indicating decreased muscle stiffness, as confirmed by the isoprenaline-induced right-downward shift of the passive length-tension relation. These effects were modulated by beta(1)- and beta(2)-adrenoceptors and PKA. In DOXO-HF group, the effect on myocardial stiffness was significantly decreased. We conclude that beta-adrenergic stimulation is a relevant mechanism of acute neurohumoral modulation of the diastolic function. Furthermore, this study clarifies the mechanisms by which myocardial stiffness is decreased.

[Supra-aortic trunks occlusive disease: three different treatment approaches]. / Doença oclusiva dos troncos supra-aórticos: Três opções de revascularização.

Unlike carotid bifurcation atherosclerotic stenosis, supra-aortic trunks (SAT) occlusive disease is rare and its revascularization uncommon, accouting for less than 10% of the operations performed on the extracranial brain-irrigating arteries. There are three different treatment approaches: transthoracic, extra-anatomic cervical and endovascular. Endovascular repair is gaining popularity as first-line therapy for proximal lesions with favorable anatomy because of its low morbidity and rare mortality. Extra-anatomic bypass is a safe and durable reconstruction and should be considered in patients with single vessel disease, with cardiopulmonary high-risk or with limited life expectancy. If cardiac surgery is needed, central transthoracic reconstruction is preferable, and the two procedures should be combined. The long-term patency of bypasses with aortic origin, specially when multiple vessels are involved, is superior to other repair techniques. We present three clinical cases that illustrate each of these therapeutic strategies: central brachiocephalic revascularization and synchronous cardiac surgery in a patient with complex SAT atherosclerosis disease; subclavian-carotid transposition for disabling upper limb claudication; and subclavian artery stenting for subclavian-steal syndrome. Surgical approach selection should be based on the individual patient's anatomy and operative risk.

Urotensin II-induced increase in myocardial distensibility is modulated by angiotensin II and endothelin-1.

Endogenous regulators, such as angiotensin-II (AngII), endothelin-1 (ET-1) and urotensin-II (U-II) are released from various cell types and their plasma levels are elevated in several cardiovascular diseases. The present study evaluated a potential crosstalk between these systems by investigating if the myocardial effects of U-II are modulated by AngII or ET-1. Effects of U-II (10(-8), 10(-7), 10(-6) M) were tested in rabbit papillary muscles in the absence and in the presence of losartan (selective AT(1) receptor antagonist), PD-145065 (nonselective ET-1 receptors antagonist), losartan plus PD-145065, AngII or ET-1. U-II promoted concentration-dependent negative inotropic and lusitropic effects that were abolished in all experimental conditions. Also, U-II increased resting muscle length up to 1.008+/-0.002 L/L(max). Correcting it to its initial value resulted in a 19.5+/-3.5 % decrease of resting tension, indicating increased muscle distensibility. This effect on muscle length was completely abolished in the presence of losartan and significantly attenuated by PD-145065 or losartan plus PD-145065. This effect was increased in the presence of AngII, resulting in a 27.5+/-3.9 % decrease of resting tension, but was unaffected by the presence of ET-1. This study demonstrated an interaction of the U-II system with the AngII and ET-1 systems in terms of regulation of systolic and diastolic function.