cardiovascular-agents and Fibrosis

Myocardial fibrosis is a remarkably dynamic process mediated by different molecular pathways that represent potential targets of novel therapeutic interventions. Transforming Growth Factor-beta (TGF-β), connective Tissue Growth Factor (cTGF) and Galectin-3 (Gal-3) represent the most promising targets on which research has been currently focusing.. This review initially discusses those drugs used in clinical practice for their anti-fibrotic properties and later examines emerging pathway-specific agents in preclinical and clinical development [phase I and II-concluded or ongoing trials]. We performed a PubMed, Embase and Google Scholar research including original articles, systematic reviews, ongoing and completed trials using combinations of keywords such as 'myocardial fibrosis', 'reverse remodeling', 'RAAs', 'therapy'.. A variety of preclinical evidences suggest that new drugs and molecules are potentially useful to target cardiac fibrosis and improve left ventricular function, reduce infarct size and scars, delay incident heart failure and cardiac dysfunction in animal models. However, there are very few clinical trials investigating the effect of such drugs in this setting, as well as a lack of new engineered molecules for specific targets.

Topics: Animals; Biomarkers; Cardiomyopathies; Cardiovascular Agents; Fibrosis; Humans; Molecular Targeted Therapy; Myocytes, Cardiac; Signal Transduction; Treatment Outcome

Cardiovascular fibrosis refers to the scar tissue that develops in the injured heart and blood vessels from an aberrant wound healing response to organ injury or insult. Established fibrosis becomes a hallmark of chronic disease progression and a key contributor to tissue stiffness and dysfunction, which ultimately leads to heart failure. As wound healing and fibrotic responses to myocardial injury are multifactorial processes, current therapies that only target specific contributing factors to disease pathogenesis offer limited overall anti-fibrotic efficacy. As such, recent attention has turned to targeting the body's immune system, which orchestrates the wound healing response to tissue injury. This review focuses on the increasing body of work that has identified the NLRP3 inflammasome, a multiprotein oligomer complex responsible for activation of inflammatory responses via its production of IL-1β and IL-18, as an immune system-initiated facilitator of cardiovascular healing, but also an important contributor to tissue scarring following its persistent activation. The review summarises the factors that can elicit priming and activation of the inflammasome complex, how the activated inflammasome complex contributes to cardiovascular pathophysiology and fibrosis progression, and the molecular mechanisms involved from various cell culture and animal model studies that have utilised genetic deletion or pharmacological inhibition of specific components of the inflammasome. Finally, it outlines currently known and previously unrecognised cardiovascular receptors that may be pharmacologically targeted to ablate the contribution of the NLRP3 inflammasome to cardiovascular diseases characterised by fibrosis, by compounds that may be developed as effective adjunct therapies to current standard of care medication.

Topics: Animals; Cardiovascular Agents; Cardiovascular Diseases; Drug Delivery Systems; Fibrosis; Humans; NLR Family, Pyrin Domain-Containing 3 Protein; Treatment Outcome

The prevalence of heart failure (HF) with preserved ejection fraction (HFpEF) is higher than that of HF with reduced/midrange ejection fraction (HFrEF/HFmrEF). However, no evidence-based guidelines for managing HFpEF have been generated. The current body of knowledge indicates that fibrosis and inflammation are important components of the cardiac remodeling process in HFpEF. In addition, macrophages potentially play an important role in pro-inflammatory and profibrotic processes in HFpEF patients, whereas HFpEF comorbidities could be a driving force for systemic microvascular inflammation and endothelial dysfunction. Under such circumstances, macrophages reportedly contribute to inflammation and fibrosis through 3 phases namely, inflammation, repair, and resolution. Signal transduction pathway-targeted therapies using animal experiments have generated important discoveries and breakthroughs for understanding the underlying mechanisms of HFpEF. However, only a handful of studies have reported promising results using human trials. Further investigations are therefore needed to elucidate the exact mechanisms underlying HFpEF and immune-pathogenesis of cardiac fibrosis.

Topics: Animals; Anti-Inflammatory Agents; Cardiovascular Agents; Comorbidity; Fibrosis; Heart Failure; Humans; Inflammation; Inflammation Mediators; Macrophages; Molecular Targeted Therapy; Myocardium; Signal Transduction; Stroke Volume; Ventricular Function, Left

A wide range of histone deacetylase (HDAC) inhibitors have been studied for their therapeutic potential because the excessive activity and expression of HDACs have been implicated in the pathogenesis of cardiac diseases. An increasing number of preclinical studies have demonstrated the cardioprotective effects of numerous HDAC inhibitors, suggesting a wide variety of mechanisms by which the inhibitors protect against cardiac stress, such as the suppression of cardiac fibrosis and fetal gene expression, enhancement of angiogenesis and mitochondrial biogenesis, prevention of electrical remodeling, and regulation of apoptosis, autophagy, and cell cycle arrest. For the development of isoform-selective HDAC inhibitors with high efficacy and low toxicity, it is important to identify and understand the mechanisms responsible for the effects of the inhibitors. This review highlights the preclinical effects of HDAC inhibitors that act against Zn

Topics: Animals; Antihypertensive Agents; Atrial Fibrillation; Blood Pressure; Cardiomegaly; Cardiovascular Agents; Fibrosis; Heart Rate; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hypertension; Myocardial Infarction; Myocardium; Signal Transduction; Ventricular Remodeling

Atrial fibrillation (AF) is the most common type of arrhythmia in the general population with a prevalence that reaches one third of patients with arterial hypertension. Several risk factors frequently associated with hypertension predispose the myocardium to AF by inducing atrial inflammation and fibrosis and altering atrial electrical and mechanical characteristics. AF influences the quality of life of hypertensive patients since it increases incidence of stroke and other thromboembolic events, and mortality. Polyunsaturated fatty acids of the ω-3 family (ω-3 PUFA) have been demonstrated to be beneficial in cardiovascular disease prevention by reducing plasma lipids and blood pressure levels and decreasing the risk of sudden death. These fatty acids can act as potent anti-inflammatory and anti-arrhythmic agents. Many studies have investigated a possible preventive effect of ω-3 PUFA on incident AF reporting contradictory results. This article overviews the evidence currently available on this important topic and provides some conclusive remarks on the possibility that these fatty acids could be beneficial in hypertensive patients.

Topics: Atrial Fibrillation; Cardiovascular Agents; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Fibrosis; Humans; Hypertension; Incidence; Inflammation; Quality of Life; Risk Factors

Coronary artery calcification is concomitant with the development of advanced atherosclerosis. Coronary artery calcification pathologically begins as microcalcifications (0.5 to 15.0 μm) and grows into larger calcium fragments, which eventually result in sheet-like deposits (>3 mm). This evolution is observed to occur concurrently with the progression of plaque. These fragments and sheets of calcification can be easily identified by radiography as well as by computed tomography and intravascular imaging. Many imaging modalities have proposed spotty calcification to be a predictor of unstable plaque and have suggested more extensive calcification to be associated with stable plaques and perhaps the use of statin therapy. We will review the pathology of coronary calcification in humans with a focus on risk factors, relationship with plaque progression, correlation with plaque (in)stability, and effect of pharmacologic interventions.

Topics: Adult; Aged; Aged, 80 and over; Animals; Biopsy; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Disease Progression; Female; Fibrosis; Humans; Male; Middle Aged; Necrosis; Plaque, Atherosclerotic; Prognosis; Risk Factors; Rupture, Spontaneous; Severity of Illness Index; Ultrasonography, Interventional; Vascular Calcification

A series of hemodynamic and pathological responses occur in chronic aortic regurgitation, which eventually result in myocardial fibrosis and irreversible left ventricular dysfunction. According to guidelines, valvular surgery is recommended with the development of symptoms, left ventricular systolic dysfunction, or left ventricular dilatation. The optimal timing of surgical intervention has recently been questioned with documentation of irreversible myocardial damage resulting in incomplete left ventricular recovery and adverse clinical outcomes after surgery. Recognizing the shortcomings of the guidelines, we performed a comprehensive review on the novel diagnostic methods that have been shown to improve the detection of subclinical ventricular dysfunction in chronic aortic regurgitation and to improve prediction of outcomes.

Topics: Aged; Aortic Valve Insufficiency; Asymptomatic Diseases; Cardiovascular Agents; Chronic Disease; Disease Progression; Early Diagnosis; Female; Fibrosis; Heart Valve Prosthesis Implantation; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Myocardium; Predictive Value of Tests; Recovery of Function; Time Factors; Time-to-Treatment; Treatment Outcome; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

The underlying cause of cardiac hypertrophy, fibrosis, and heart failure has been investigated in great detail using different mouse models. These studies indicated that cGMP and cGMP-dependent protein kinase type I (cGKI) may ameliorate these negative phenotypes in the adult heart. Recently, evidence has been published that cardiac mitochondrial BKCa channels are a target for cGKI and that activation of mitoBKCa channels may cause some of the positive effects of conditioning in ischemia/reperfusion injury. It will be pointed out that most studies could not present convincing evidence that it is the cGMP level and the activity cGKI in specific cardiac cells that reduces hypertrophy or heart failure. However, anti-fibrotic compounds stimulating nitric oxide-sensitive guanylyl cyclase may be an upcoming therapy for abnormal cardiac remodeling.

Topics: Animals; Cardiomegaly; Cardiovascular Agents; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Fibrosis; Heart Failure; Humans; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; Mitochondria, Heart; Myocardial Reperfusion Injury; Myocardium; Second Messenger Systems; Ventricular Remodeling

Quantifying myocardial fibrosis (MF) with myocardial extracellular volume measures acquired during cardiovascular magnetic resonance promises to transform clinical care by advancing pathophysiologic understanding and fostering novel therapeutics. Extracellular volume quantifies MF by measuring the extracellular compartment depicted by the myocardial uptake of contrast relative to plasma. MF is a key domain of dysfunctional but viable myocardium among others (eg, microvascular dysfunction and cardiomyocyte/mitochondrial dysfunction). Although anatomically distinct, these domains may functionally interact. MF represents pathological remodeling in the heart associated with cardiac dysfunction and adverse outcomes likely mediated by interactions with the microvasculature and the cardiomyocyte. Reversal of MF improves key measures of cardiac dysfunction, so reversal of MF represents a likely mechanism for improved outcomes. Instead of characterizing the myocardium as homogenous tissue and using important yet still generic descriptors, such as thickness (hypertrophy) and function (diastolic or systolic), which lack mechanistic specificity, paradigms of cardiac disease have evolved to conceptualize myocardial disease and patient vulnerability based on the extent of disease involving its various compartments. Specifying myocardial compartmental involvement may then implicate cellular/molecular disease pathways for treatment and targeted pharmaceutical development and above all highlight the role of the cardiac-specific pathology in heart failure among myriad other changes in the heart and beyond. The cardiology community now requires phase 2 and 3 clinical trials to examine strategies for the regression/prevention of MF and eventually biomarkers to identify MF without reliance on cardiovascular magnetic resonance. It seems likely that efficacious antifibrotic therapy will improve outcomes, but definitive data are needed.

Topics: Animals; Cardiomyopathies; Cardiovascular Agents; Contrast Media; Fibrosis; Heart Failure; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Myocardium; Predictive Value of Tests; Prognosis; Ventricular Remodeling

Topics: Adrenergic beta-Antagonists; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiovascular Agents; Chronic Disease; Fibrosis; Heart Failure; Humans; Mineralocorticoid Receptor Antagonists; Recovery of Function; Renin-Angiotensin System; Risk Factors; Stroke Volume; Sympathetic Nervous System; Treatment Outcome; Ventricular Remodeling

Although angiotensin II subtype-2 receptor (AT2R) was discovered over 2 decades ago, its contribution to physiology and pathophysiology is not fully elucidated. Current knowledge suggests that under normal physiologic conditions, AT2R counterbalances the effects of angiotensin II subtype-1 receptor (AT1R). A major obstacle for AT2R investigations was the lack of specific agonists. Most of the earlier AT2R studies were performed using the peptidic agonist, CG42112A, or the nonpeptidic antagonist PD123319. CGP42112A is nonspecific for AT2R and in higher concentrations can bind to AT1R. Recently, the development of specific nonpeptidic AT2R agonists boosted the efforts in identifying the therapeutic potentials for AT2R stimulation. Unlike AT1R, AT2R is involved in vasodilation by the release of bradykinin and nitric oxide, anti-inflammation, and healing from injury. Interestingly, the vasodilatory effects of AT2R stimulation were not associated with significant reduction in blood pressure. In the kidney, AT2R stimulation produced natriuresis, increased renal blood flow, and reduced tissue inflammation. In animal studies, enhanced AT2R function led to reduction of cardiac inflammation and fibrosis, and reduced the size of the infarcted area. Similarly, AT2R stimulation demonstrated protective effects in vasculature and brain.

Topics: Animals; Anti-Inflammatory Agents; Brain; Cardiovascular Agents; Cardiovascular System; Drug Design; Fibrosis; Humans; Kidney; Molecular Targeted Therapy; Neuroprotective Agents; Receptor, Angiotensin, Type 2; Renin-Angiotensin System; Signal Transduction; Ventricular Remodeling

Chronic heart failure (CHF) is a growing health problem in developed nations. The pathological accumulation of extracellular matrix is a key contributor to CHF in both diabetic and nondiabetic states, resulting in progressive stiffening of the ventricular walls and loss of contractility. Proinflammatory disease processes, including inflammatory cytokine activation, contribute to accumulation of extracellular matrix in the heart. Transforming growth factor-β is a key profibrotic cytokine mediating fibrosis. Current therapeutic strategies do not directly target the profibrotic inflammatory processes occurring in the heart and hence there is a clear unmet clinical need to develop new therapeutic agents targeting fibrosis. Accordingly, strategies that inhibit proinflammatory cytokine activation and pathological accumulation of extracellular matrix (ECM) provide a potential therapeutic target for prevention of heart failure. This review focuses on the therapeutic targeting of TGF-β in the prevention of pathological fibrosis in the heart.

Topics: Animals; Cardiovascular Agents; Chronic Disease; Extracellular Matrix Proteins; Fibrosis; Heart Failure; Humans; Inflammation Mediators; Myocardium; Signal Transduction; Transforming Growth Factor beta; Ventricular Remodeling

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, affecting over one million individuals in Europe. Hypertrophic cardiomyopathy patients often require pharmacological intervention for control of symptoms, dynamic left ventricular outflow obstruction, supraventricular and ventricular arrhythmias, and microvascular ischaemia. Current treatment strategies in HCM are predicated on the empirical use of long-standing drugs, such as beta-adrenergic and calcium blockers, although with little evidence supporting their clinical benefit in this disease. In the six decades since the original description of the disease, <50 pharmacological studies enrolling little over 2000 HCM patients have been performed, the majority of which were small, non-randomized cohorts. As our understanding of the genetic basis and pathophysiology of HCM improves, the availability of transgenic and preclinical models uncovers clues to novel and promising treatment modalities. Furthermore, the number of patients identified and followed at international referral centres has grown steadily over the decades. As a result, the opportunity now exists to implement adequately designed pharmacological trials in HCM, using established as well as novel drug therapies, to potentially intervene on the complex pathophysiology of the disease and alter its natural course. Therefore, it is timely to review the available evidence for pharmacological therapy of HCM patients, highlight the most relevant gaps in knowledge, and address some of the most promising areas for future pharmacological research, in an effort to move HCM into the era of evidence-based management.

Topics: Anti-Arrhythmia Agents; Atrial Fibrillation; Cardiomyopathy, Hypertrophic, Familial; Cardiovascular Agents; Drug Evaluation, Preclinical; Drug Therapy, Combination; Evidence-Based Medicine; Fibrosis; Humans; Myocardium; Randomized Controlled Trials as Topic; Treatment Outcome; Ventricular Outflow Obstruction

Topics: Adrenergic beta-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Calcinosis; Cardiovascular Agents; Diabetic Angiopathies; Fibrosis; Heart Failure; Humans; Hypoglycemic Agents; Myocardium; Prognosis; Risk Factors

Hypertrophic cardiomyopathy (HCM) is microscopically characterized by cardiomyocyte hypertrophy, myofibrillar disarray, and fibrosis. During the evolvement of the hypertrophic disease, myocardium suffers a heterogeneous remodeling which includes enhancement of extracellular matrix. The most commonly used pharmacological agents are β- blockers and verapamil, a calcium antagonist, which are the mainstay of therapy. Their proposed mechanisms of effect include improved ventricular relaxation, and increased diastolic filling time but its impact on HCM pathophysiology remains unclear. The results of genetic and pharmacological studies in animal models suggest that cardiac hypertrophy and fibrosis in HCM are potentially reversible. However, current pharmacological treatments of HCM in patients, while are effective for symptomatic improvement, have not been established to prevent, ameliorate, or reverse cardiac hypertrophy in patients. An effective treatment of HCM has to target the molecular mechanisms that are involved in the pathogenesis of the phenotype and novel pharmacological therapies are moving in that direction. In this review, we analyse potential beneficial effects of specific experimental pharmacological agents on decreasing myocardial hypertrophy, regression of fibrosis or improving myocardial metabolic efficiency.

Topics: Calcium Channel Blockers; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Fibrosis; Humans; Myocardium; Myocytes, Cardiac; Ventricular Remodeling

Progressive heart failure associated with left ventricular remodeling and systo-diastolic dysfunction is one of the most severe complications of hypertrophic cardiomyopathy (HCM). Such condition, for the lack of a better term, is referred to as end-stage (ES) HCM. During the last decade, we have begun to understand the mechanisms underlying progression from a hyperdynamic left ventricle to the striking patterns of ES. To date, different aspects of HCM progression remain obscure, including potential strategies for management and prevention. On the basis of recent evidence, it is appropriate to emphasize these aspects, which may be difficult to identify, particularly in the early stages when systolic function appears relatively preserved. Nevertheless, it is at these early stages that treatment may potentially interfere with the clinical evolution of HCM toward ES and heart failure. The possibility of early identification of patients at risk of ES progression may ultimately impact on the natural history of the disease in this challenging patient subgroup.

Topics: Age of Onset; Cardiac Myosins; Cardiomyopathy, Hypertrophic, Familial; Cardiovascular Agents; Carrier Proteins; Defibrillators, Implantable; Disease Progression; Fibrosis; Genetic Testing; Heart Failure; Heart Transplantation; Humans; Magnetic Resonance Imaging; Microcirculation; Models, Cardiovascular; Myosin Heavy Chains; Sarcomeres; Systole; Ultrasonography; Ventricular Remodeling

Half of heart failure patients have diastolic heart failure, which has no effective treatments. Several studies indicate a role for ω-3 polyunsaturated fatty acids (PUFAs) in heart failure. Recent studies suggest that ω-3 PUFAs inhibit cardiac fibrosis and attenuate diastolic dysfunction. This opens up possible new avenues for treatment of diastolic heart failure. In this review, we focus on the antifibrotic effects of ω-3 PUFAs in heart and the underlying cellular and molecular mechanisms.

Topics: Animals; Cardiovascular Agents; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Diastole; Fatty Acids, Omega-3; Fibroblasts; Fibrosis; Heart Failure, Diastolic; Humans; Myocardium; Nitric Oxide; Signal Transduction; Transforming Growth Factor beta1

Fibrosis is one of the largest groups of diseases for which there is no therapy but is believed to occur because of a persistent tissue repair program. During connective tissue repair, "activated" fibroblasts migrate into the wound area, where they synthesize and remodel newly created extracellular matrix. The specialized type of fibroblast responsible for this action is the alpha-smooth muscle actin (alpha-SMA)-expressing myofibroblast. Abnormal persistence of the myofibroblast is a hallmark of fibrotic diseases. Proteins such as transforming growth factor (TGF)beta, endothelin-1, angiotensin II (Ang II), connective tissue growth factor (CCN2/CTGF), and platelet-derived growth factor (PDGF) appear to act in a network that contributes to myofibroblast differentiation and persistence. Drugs targeting these proteins are currently under consideration as antifibrotic treatments. This review summarizes recent observations concerning the contribution of TGFbeta, endothelin-1, Ang II, CCN2, and PDGF and to fibroblast activation in tissue repair and fibrosis and the potential utility of agents blocking these proteins in affecting the outcome of cardiac fibrosis.

Topics: Angiotensin II; Animals; Cardiovascular Agents; Connective Tissue Growth Factor; Drug Design; Endothelin-1; Extracellular Matrix Proteins; Fibroblasts; Fibrosis; Heart Diseases; Humans; Myocardium; Platelet-Derived Growth Factor; Signal Transduction; Transforming Growth Factor beta

Fifty years after its discovery, aldosterone continues to stimulate interest as a therapeutic target. Early studies focused on aldosterone's actions on hypertension, the kidney, and electrolyte handling. More recently, its actions on the heart and cardiovascular system have become more apparent. Aldosterone causes cardiac fibrosis and remodeling, and stimulates neurohormonal systems that adversely affect the cardiovascular system. Aldosterone antagonism attenuates these negative effects. Clinical studies have applied this science and demonstrated improved morbidity and mortality with aldosterone blockade, specifically in patients with chronic heart failure and patients who are postmyocardial infarction and with depressed left ventricular function. This article will address the pathophysiology of aldosterone in cardiac fibrosis and remodeling, review the current clinical trial data, and explore the application of aldosterone blockade in an expanded heart failure population. The Randomized Aldactone Evaluation Study showed that the aldosterone antagonist spironolactone reduced mortality when compared to placebo in patients with chronic advanced heart failure. Similarly, the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study demonstrated a significant reduction in mortality and hospitalizations for patients randomized to the aldosterone antagonist eplerenone. A more provocative question is whether aldosterone antagonism will afford the same protection in patient populations with heart failure and preserved left ventricular function. Clinical trials are underway, and results are eagerly awaited.

Topics: Aldosterone; Cardiovascular Agents; Drug Therapy, Combination; Eplerenone; Fibrosis; Heart Failure; Humans; Mineralocorticoid Receptor Antagonists; Myocardium; Spironolactone; Treatment Outcome; Ventricular Dysfunction, Left; Ventricular Remodeling

The quintessential clinical diagnostic phenotype of human hypertrophic cardiomyopathy (HCM) is primary cardiac hypertrophy. Cardiac hypertrophy is also a major determinant of mortality and morbidity including the risk of sudden cardiac death (SCD) in patients with HCM. Reversal and attenuation of cardiac hypertrophy and its accompanying fibrosis is expected to improve morbidity as well as decrease the risk of SCD in patients with HCM.The conventionally used pharmacological agents in treatment of patients with HCM have not been shown to reverse or attenuate established cardiac hypertrophy and fibrosis. An effective treatment of HCM has to target the molecular mechanisms that are involved in the pathogenesis of the phenotype. Mechanistic studies suggest that cardiac hypertrophy in HCM is secondary to activation of various hypertrophic signaling molecules and, hence, is potentially reversible. The hypothesis is supported by the results of genetic and pharmacological interventions in animal models. The results have shown potential beneficial effects of angiotensin II receptor blocker losartan, mineralocorticoid receptor blocker spironolactone, 3-hydroxy-3-methyglutaryl-coenzyme A reductase inhibitors simvastatin and atorvastatin, and most recently, N-acetylcysteine (NAC) on reversal or prevention of hypertrophy and fibrosis in HCM. The most promising results have been obtained with NAC, which through multiple thiol-responsive mechanisms completely reversed established cardiac hypertrophy and fibrosis in three independent studies. Pilot studies with losartan and statins in humans have established the feasibility of such studies. The results in animal models have firmly established the reversibility of established cardiac hypertrophy and fibrosis in HCM and have set the stage for advancing the findings in the animal models to human patients with HCM through conducting large-scale efficacy studies.

Topics: Animals; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Death, Sudden, Cardiac; Drugs, Investigational; Fibrosis; Genetic Predisposition to Disease; Humans; Myocardium; Phenotype; Treatment Outcome

Atrial fibrillation occurs and maintains itself in the context of a morphologically and functionally altered atrial substrate that can be induced by stressors such as underlying diseases (cardiac or noncardiac) or aging. The resultant structural remodeling is a slow process that progressively affects myocytes and the myocardial interstitium, and takes place from as early as the first days of atrial tachyarrhythmia. The left atrium, and particularly its posterior wall, is the location where remodeling is concentrated to the greatest extent. The mechanisms that underlie the remodeling process in atrial fibrillation have not yet been completely elucidated, although experimental and clinical investigations have indicated a number of signaling systems, inflammation, oxidative stress, atrial stretching and ischemia as factors involved in the cascade of events that leads to atrial fibrillation. The aim of this Review is to provide a comprehensive overview of the morphological changes that characterize the fibrillating atrial myocardium at histological and ultrastructural levels, and the established and hypothetical pathogenetic mechanisms involved in structural remodeling. This article also highlights the emerging therapies being developed to prevent progression of atrial fibrillation.

Topics: Animals; Atrial Fibrillation; Atrial Function; Cardiovascular Agents; Catheter Ablation; Cell Death; Connexins; Disease Models, Animal; Disease Progression; Fibrosis; Heart Atria; Humans; Inflammation; Myocardial Ischemia; Myocardium; Oxidative Stress; Risk Factors; Tachycardia, Supraventricular; Treatment Outcome

Systemic sclerosis (SSc) is a complex and heterogeneous chronic illness characterized by substantial patient to patient variability in clinical manifestations, internal organ involvement, and outcome. Genetic factors contribute to disease susceptibility, but environmental influences also play a significant role. The pathogenesis of SSc encompasses vascular, immunological, and fibrotic processes, which contribute to clinical manifestations and morbidity and must be addressed in the treatment plan. Although vascular interventions appear to reduce the frequency and severity of complications, such as scleroderma renal crisis and pulmonary hypertension, current therapies generally target the immune component of SSc in a non-selective fashion and have largely failed as diseases-modifying interventions. Newer insights into the mechanisms underlying autoimmunity, vascular injury and destruction, and particularly tissue fibrosis provide novel potential targets for therapy. Transforming growth factor-ss is a ubiquitous cytokine that appears to contribute to fibroblast activation, collagen overproduction, and pathological tissue fibrosis. Neutralizing antibodies and small molecules that block TGF-beta activation or function are effective in shutting down TGF-beta signaling and selectively inhibit the progression of fibrosis and may be entering clinical trials for the treatment of SSc.

Topics: Blood Vessels; Cardiovascular Agents; Fibrosis; Genetic Predisposition to Disease; Humans; Hypertension, Pulmonary; Immunosuppressive Agents; Inflammation; Kidney Diseases; Lung Diseases, Interstitial; Raynaud Disease; Scleroderma, Systemic; Skin; Transforming Growth Factor beta; Treatment Outcome

The renin-angiotensin system, traditionally viewed as a circulatory system, has significantly expanded in the last two decades to include independently regulated local systems in several tissues, newly identified active products of angiotensin II, and new receptors and functions of renin-angiotensin system components. In spite of our increased understanding of the renin-angiotensin system, a role of angiotensin II in cardiac hypertrophy, through direct effects on cardiovascular tissue, is still being debated. Here, we address the cardiovascular effects of angiotensin II and the role an intracellular renin-angiotensin system might play.. Recent studies have shown that cardiac myocytes, fibroblasts and vascular smooth muscle cells synthesize angiotensin II intracellularly. Some conditions, such as high glucose, selectively increase intracellular generation and translocation of angiotensin II to the nucleus. Intracellular angiotensin II regulates the expression of angiotensinogen and renin, generating a feedback loop. The first reaction of intracellular angiotensin II synthesis is catalyzed by renin or cathepsin D, depending on the cell type, and chymase, not angiotensin-converting enzyme, catalyzes the second step.. These studies suggest that the intracellular renin-angiotensin system is an important component of the local system. Alternative mechanisms of angiotensin II synthesis and action suggest a need for novel therapeutic agents to block the intracellular renin-angiotensin system.

Topics: Angiotensin II; Animals; Cardiomegaly; Cardiovascular Agents; Extracellular Fluid; Fibrosis; Humans; Intracellular Fluid; Myocardium; Renin-Angiotensin System; Signal Transduction; Ventricular Remodeling

Cirrhotic cardiomyopathy is a recently identified pathological condition defined as "a chronic cardiac dysfunction in patients with cirrhosis characterized by blunted contractile responsiveness to stress and/or altered diastolic relaxation with electrophysiological abnormalities, in the absence of known cardiac disease". Overall there seems to be a link between the progression of liver function impairment, the development of portal hypertension and the degree of hyperdynamic circulation, the hallmark of the deranged cardiovascular function in advanced liver diseases. Although mechanical factors contribute to much of the increased resistance within the liver in portal hypertension, there is clearly a vasculogenic component to the development, perpetuation and progression of this syndrome as well. The vascular component of portal hypertension includes an increase in splanchnic blood flow, as well as an increase in intrahepatic vascular resistance. Dysregulation of the nitric oxide system appears to play a key role in both these processes with a paradoxical reduction of intrahepatic availability despite increased disposal in the splanchnic and other vascular districts with adverse effects on cardiac function and structure. Nevertheless, other putative mediators of cardiac damage in cirrhosis have been proposed and their role in the pathogenesis of cirrhotic cardiomyopathy investigated. This review involves a discussion of data achieved on pathogenesis and clinical features of cirrhotic cardiomyopathy but mainly focuses on considerations on potential therapeutic targets, in the light of the evidence that this mainly subclinical condition merges to clinical relevance when challenged with those therapeutic interventions and procedures currently employed to treat the major complications of cirrhosis that might produce a negative impact on the cardiovascular system.

Topics: Animals; Cardiomyopathies; Cardiovascular Agents; Fibrosis; Humans

Although the features of diabetic cardiomyopathy, atherosclerosis, and nephropathy have been clinically characterized, the pathogenesis and the mechanisms underlying the abnormalities in the diabetic heart and kidney are not fully understood. During the past several years, in an attempt to discover interventions for diabetes-related complications, researchers have refocused their attention from the hemodynamic aspects of the disease to the biochemical interactions of glucose and proteins. Diabetes is a disorder of chronic hyperglycemia, and glucose participates in diabetic complications such as atherosclerosis, cardiac dysfunction, and nephropathy. Chronic hyperglycemia accelerates the reaction between glucose and proteins and leads to the formation of advanced glycation end products (AGE), which form irreversible cross-links with many macromolecules such as collagen. In diabetes, these AGE accumulate in tissues at an accelerated rate. The development of the novel compound dimethyl-3-phenacylthiazolium chloride (alagebrium chloride), which chemically breaks AGE cross-links, led to several preclinical animal studies that showed an attenuation or reversal of disease processes of the heart and kidney. In diabetes, AGE not only structurally stiffen structural collagen backbones but also act as agonists to AGE receptors (RAGE) on various cell types, which stimulate the release of profibrotic growth factors, promote collagen deposition, increase inflammation, and ultimately lead to tissue fibrosis. In the heart, large vessels, and kidney, these reactions produce diastolic dysfunction, atherosclerosis, and renal fibrosis. Administration of the cross-link breaker alagebrium chloride in these diabetic animals attenuates these pathologic phenomena, restoring functionality to the heart, vasculature, and kidney.

Topics: Animals; Atherosclerosis; Blood Glucose; Cardiomyopathies; Cardiovascular Agents; Diabetic Angiopathies; Diabetic Nephropathies; Fibrosis; Glycation End Products, Advanced; Humans; Myocardium; Thiazoles

The pathomechanisms underlying restenosis of the bioabsorbable sirolimus-eluting metallic scaffold (Magmaris) remain unknown. Using serial optical coherence tomography, we investigated causes of restenosis, including the contribution of late scaffold recoil versus neointimal hyperplasia.. Patients enrolled in BIOSOLVE-II undergoing serial angiography and optical coherence tomography (post-intervention and follow-up: 6 months and/or 1 year) were analyzed. Patients were divided into 2 groups according to angiographic in-scaffold late lumen loss (LLL) <0.5 or ≥0.5 mm. End points were late absolute scaffold recoil and neointimal hyperplasia area as assessed by optical coherence tomography.. In addition to neointimal hyperplasia, late scaffold recoil contributed significantly to LLL of sirolimus-eluting absorbable metal scaffolds. The extent of late scaffold recoil was dependent on the underlying plaque morphology and was the highest among fibrotic lesions. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01960504.

Topics: Absorbable Implants; Aged; Cardiovascular Agents; Coronary Restenosis; Coronary Vessels; Female; Fibrosis; Humans; Male; Metals; Middle Aged; Myocardial Ischemia; Neointima; Percutaneous Coronary Intervention; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

The aim of this study was to evaluate the pathophysiological features and response to primary percutaneous coronary intervention (PCI) of nonruptured/eroded plaque versus ruptured plaque as a cause of ST-segment elevation myocardial infarction (STEMI).. Autopsy series identified nonruptured/eroded plaque and ruptured plaque as the principal pathological substrates underlying coronary thrombosis in STEMI. The real incidence of different plaque morphologies, associated biological factors, superimposed thrombus, and their interaction with primary PCI remain largely unknown.. In a prospective study, 140 patients with STEMI underwent optical coherence tomography of the infarct-related artery (IRA) before PCI, after everolimus-eluting stent implantation and at 9-month follow-up. Histopathology and immunohistochemistry of thrombus aspirates and serum biomarkers were assessed at baseline.. Culprit plaque morphology was adjudicated in 97 patients: 32 plaques (33.0%) with an intact fibrous cap (IFC), 63 (64.9%) plaques with a ruptured fibrous cap (RFC), and 2 (2.1%) spontaneous dissections. Patients with an IFC and RFC had similar clinical characteristics, and serum inflammatory and platelets biomarkers. An IFC presented more frequently with a patent IRA (56.2% vs. 34.9%; p = 0.047), and had fewer lipid areas (lipid-rich areas: 75.0% vs. 100.0%; p < 0.001) and less residual thrombus before stenting (white thrombus: 0.41 mm(3) vs. 1.52 mm(3); p = 0.001; red thrombus: 0 mm(3) vs. 0.29 mm(3); p = 0.001) with a lower peak of creatine kinase-myocardial band (66.6 IU/l vs. 149.8 IU/l; p = 0.025). At the 9-month optical coherence tomography, IFC and RFC had similar high rates of stent strut coverage (92.5% vs. 91.2%; p = 0.15) and similar percentage of volume obstruction (12.6% vs. 10.2%; p = 0.27). No significant differences in clinical outcomes were observed up to 2 years.. In the present study, an IFC was observed at the culprit lesion site of one-third of STEMIs. IFC, compared with RFC, was associated with higher rates of patent IRA at first angiography, fewer lipid areas, and residual endoluminal thrombus. However, no difference in vascular response to everolimus-eluting stent was observed. (Optical Coherence Tomography Assessment of Gender Diversity in Primary Angioplasty [OCTAVIA]; NCT01377207).

Topics: Aged; Biomarkers; Cardiovascular Agents; Coronary Artery Disease; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Fibrosis; Humans; Immunohistochemistry; Inflammation Mediators; Italy; Male; Middle Aged; Myocardial Infarction; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Prospective Studies; Prosthesis Design; Rupture, Spontaneous; Thrombectomy; Time Factors; Tomography, Optical Coherence; Treatment Outcome

Development of a cardiomyopathy in diabetes mellitus is independent of traditional risk factors, with no clinical trials targeting specific therapeutic interventions. Myocardial fibrosis is one of the key mechanisms and aldosterone is a key mediator of myocardial fibrosis. We propose that aldosterone antagonism will improve cardiac function. We aim to evaluate the efficacy of selective aldosterone receptor antagonism with eplerenone added to optimal medical treatment in improving cardiac structure and function in diabetic cardiomyopathy. We will randomize 130 patients with type 2 diabetes mellitus, stable metabolic control and impaired left ventricular (LV) systolic or diastolic function, to either eplerenone (target dose 50mg) or matching placebo, in addition to optimal medical therapy for 12 months. The primary endpoints are changes in LV systolic and diastolic function, measured by echocardiographic 2-dimensional speckle tracking strain and strain rate and tissue Doppler imaging. The secondary endpoints include changes in echocardiographic markers and plasma biomarkers of collagen turnover; left atrial dimensions and function, incidence of atrial fibrillation and changes in exercise capacity and dyspnea score. The present study will assess whether specific aldosterone antagonism with eplerenone in addition to standard therapy will prevent progression or reverse cardiac dysfunction in diabetic cardiomyopathy using sensitive, robust and quantifiable echocardiographic measures that allow early detection of change. The study may offer a new direction in the management of this condition.. ACTRN12610001063000.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Cardiovascular Agents; Clinical Protocols; Collagen; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Diastole; Double-Blind Method; Drug Therapy, Combination; Echocardiography, Doppler; Eplerenone; Fibrosis; Humans; Mineralocorticoid Receptor Antagonists; Myocardium; New South Wales; Prospective Studies; Recovery of Function; Research Design; Spironolactone; Systole; Time Factors; Treatment Outcome; Ventricular Function, Left

Serial intravascular ultrasound virtual histology (IVUS-VH) after implantation of metallic stents has been unable to show any changes in the composition of the scaffolded plaque overtime. The everolimus-eluting ABSORB scaffold potentially allows for the formation of new fibrotic tissue on the scaffolded coronary plaque during bioresorption. We examined the 12 month IVUS-VH changes in composition of the plaque behind the struts (PBS) following the implantation of the ABSORB scaffold. Using IVUS-VH and dedicated software, the composition of the PBS was analyzed in all patients from the ABSORB Cohort B2 trial, who were imaged with a commercially available IVUS-VH console (s5i system, Volcano Corporation, Rancho Cordova, CA, USA), immediately post-ABSORB implantation and at 12 month follow-up. Paired IVUS-VH data, recorded with s5i system, were available in 17 patients (18 lesions). The analysis demonstrated an increase in mean PBS area (2.39 ± 1.85 mm(2) vs. 2.76 ± 1.79 mm(2), P = 0.078) and a reduction in the mean lumen area (6.37 ± 0.90 mm(2) vs. 5.98 ± 0.97 mm(2), P = 0.006). Conversely, a significant decrease of 16 and 30% in necrotic core (NC) and dense calcium (DC) content, respectively, were evident (median % NC from 43.24 to 36.06%, P = 0.016; median % DC from 20.28 to 11.36%, P = 0.002). Serial IVUS-VH analyses of plaque located behind the ABSORB struts at 12-month demonstrated an increase in plaque area with a decrease in its NC and DC content. Larger studies are required to investigate the clinical impact of these findings.

Topics: Absorbable Implants; Aged; Australia; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Europe; Everolimus; Female; Fibrosis; Humans; Male; Middle Aged; Necrosis; New Zealand; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Predictive Value of Tests; Prosthesis Design; Sirolimus; Time Factors; Tissue Scaffolds; Treatment Outcome; Ultrasonography, Interventional

To quantify the circumferential healing process at 6 and 12 months following scaffold implantation.. The healing process following stent implantation consists of tissue growing on the top of and in the space between each strut. With the ABSORB bioresorbable vascular scaffold (BVS), the outer circumference of the scaffold is detectable by optical coherence tomography (OCT), allowing a more accurate and complete evaluation of the intra-scaffold neointima.. A total of 58 patients (59 lesions), who received an ABSORB BVS 1.1 implantation and a subsequent OCT investigation at 6 (n=28 patients/lesions) or 12 (n=30 patients with 31 lesions) months follow-up were included in the analysis. The thickness of the neointima was calculated circumferentially in the area between the abluminal side of the scaffold and the lumen by means of an automated detection algorithm. The symmetry of the neointima thickness in each cross section was evaluated as the ratio between minimum and maximum thickness.. The neointima area was not different between 6 and 12 months follow-up (1.57±0.42 mm(2) vs. 1.64±0.77 mm(2); p=0.691). No difference was also found in the mean thickness of the neointima (median [IQR]) between the two follow-up time points (210 μm [180-260]) vs. 220 μm [150-260]; p=0.904). However, the symmetry of the neointima thickness was higher at 12 than at 6 months follow-up (0.23 [0.13-0.28] vs. 0.16 [0.08-0.21], p=0.019).. A circumferential evaluation of the healing process following ABSORB implantation is feasible, showing the formation of a neointima layer, that resembles a thick fibrous cap, known for its contribution to plaque stability.

Topics: Absorbable Implants; Algorithms; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Delayed-Action Preparations; Endovascular Procedures; Everolimus; Fibrosis; Humans; Image Processing, Computer-Assisted; Neointima; Polyesters; Predictive Value of Tests; Sirolimus; Time Factors; Tissue Scaffolds; Tomography, Optical Coherence; Treatment Outcome

This study sought to investigate in vivo the vascular response at the proximal and distal edges of the second-generation ABSORB everolimus-eluting bioresorbable vascular scaffold (BVS).. The edge vascular response after implantation of the BVS has not been previously investigated.. The ABSORB Cohort B trial enrolled 101 patients and was divided into B(1) (n = 45) and B(2) (n = 56) subgroups. The adjacent (5-mm) proximal and distal vessel segments to the implanted ABSORB BVS were investigated at either 6 months (B(1)) or 1 year (B(2)) with virtual histology intravascular ultrasound (VH-IVUS) imaging.. At the 5-mm proximal edge, the only significant change was modest constrictive remodeling at 6 months (Δ vessel cross-sectional area: -1.80% [-3.18; 1.30], p < 0.05), with a tendency to regress at 1 year (Δ vessel cross-sectional area: -1.53% [-7.74; 2.48], p = 0.06). The relative change of the fibrotic and fibrofatty (FF) tissue areas at this segment were not statistically significant at either time point. At the 5-mm distal edge, a significant increase in the FF tissue of 43.32% [-19.90; 244.28], (p < 0.05) 1-year post-implantation was evident. The changes in dense calcium need to be interpreted with caution since the polymeric struts are detected as "pseudo" dense calcium structures with the VH-IVUS imaging modality.. The vascular response up to 1 year after implantation of the ABSORB BVS demonstrated some degree of proximal edge constrictive remodeling and distal edge increase in FF tissue resulting in nonsignificant plaque progression with adaptive expansive remodeling. This morphological and tissue composition behavior appears to not significantly differ from the behavior of metallic drug-eluting stents at the same observational time points.

Topics: Absorbable Implants; Aged; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Fibrosis; Humans; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Prosthesis Design; Sirolimus; Time Factors; Tissue Scaffolds; Treatment Outcome; Ultrasonography, Interventional; Vascular Calcification

Implantation of a coronary stent results in a mechanical enlargement of the coronary lumen with stretching of the surrounding atherosclerotic plaque. Using intravascular ultrasound virtual-histology (IVUS-VH) we examined the temporal changes in composition of the plaque behind the struts (PBS) following the implantation of the everolimus eluting bioresorbable vascular scaffold (BVS). Using IVUS-VH and dedicated software, the composition of plaque was analyzed in all patients from the ABSORB B trial who were imaged with a commercially available IVUS-VH console (s5i system, Volcano Corporation, Rancho Cordova, CA, USA) post-treatment and at 6-month follow-up. This dedicated software enabled analysis of the PBS after subtraction of the VH signal generated by the struts. The presence of necrotic core (NC) in contact with the lumen was also evaluated at baseline and follow-up. IVUS-VH data, recorded with s5i system, were available at baseline and 6-month follow-up in 15 patients and demonstrated an increase in both the area of PBS (2.45 ± 1.93 mm(2) vs. 3.19 ± 2.48 mm(2), P = 0.005) and the external elastic membrane area (13.76 ± 4.07 mm(2) vs. 14.76 ± 4.56 mm(2), P = 0.006). Compared to baseline there was a significant progression in the NC (0.85 ± 0.70 mm(2) vs. 1.21 ± 0.92 mm(2), P = 0.010) and fibrous tissue area (0.88 ± 0.79 mm(2) vs. 1.15 ± 1.05 mm(2), P = 0.027) of the PBS. The NC in contact with the lumen in the treated segment did not increase with follow-up (7.33 vs. 6.36%, P = 0.2). Serial IVUS-VH analysis of BVS-treated lesions at 6-month demonstrated a progression in the NC and fibrous tissue content of PBS.

Topics: Absorbable Implants; Aged; Angioplasty, Balloon, Coronary; Australia; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Europe; Everolimus; Female; Fibrosis; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Necrosis; New Zealand; Predictive Value of Tests; Prosthesis Design; Sirolimus; Software; Time Factors; Treatment Outcome; Ultrasonography, Interventional

Myocardial recovery after left ventricular assist device (LVAD) support has been reported. The LVAD Working Group Recovery Study was a prospective multicenter trial to assess the incidence of myocardial recovery in patients bridged to cardiac transplantation.. After LVAD implantation, patients were evaluated with the use of rest echocardiograms with partial LVAD support and cardiopulmonary exercise testing. Dobutamine echocardiography with hemodynamic measurements was performed in those patients with left ventricular ejection fraction >40% during resting studies. Histological analysis was performed on myocardial samples taken at LVAD implantation and explantation. Sixty-seven LVAD patients with heart failure participated in the study. After 30 days, significant improvement occurred in left ventricular ejection fraction (17+/-7% versus 34+/-12%; P<0.001) and reductions in left ventricular end-diastolic diameter (7.1+/-1.2 versus 5.1+/-1.1 cm; P<0.001) and left ventricular mass (320+/-113 versus 194+/-79 g; P<0.001) compared with before LVAD. Thirty-four percent of patients had left ventricular ejection fraction >40% with partial device support. Left ventricular ejection fraction decreased over time to pre-LVAD measurement by 120 days. Peak VO2 improved with mechanical support (13.7+/-4.2 versus 18.9+/-5.5 mL/kg per minute, 30 versus 120 days; P<0.001). Tissue analysis revealed significant reductions in myocyte size, collagen content, and cardiac tumor necrosis factor-alpha. Six subjects (9%) underwent LVAD explantation for recovery.. Cardiac function improves significantly after device implantation. Although cellular recovery and improvement in ventricular function are observed, the degree of clinical recovery is insufficient for device explantation in most patients with chronic heart failure.

Topics: Cardiovascular Agents; Combined Modality Therapy; Cytokines; Dobutamine; Exercise Test; Exercise Tolerance; Female; Fibrosis; Heart Failure; Heart Function Tests; Heart Transplantation; Heart-Assist Devices; Humans; Hypertrophy; Male; Middle Aged; Myocardium; Myocytes, Cardiac; Prospective Studies; Single-Blind Method; Stroke Volume; Treatment Outcome; Ultrasonography

Atrial fibrillation (AF) is the commonest cardiac arrhythmia, affecting 3 million people in the USA and 8 million in the EU (according to the European Society of Cardiology). So, why is it that even with the best medical care, around a third of the patients are treatment resistant. Extensive research of its etiology showed that AF and its mechanisms are still debatable. Some of the AF origins are ascribed to functional and ionic heterogeneities of the heart tissue and possibly to additional triggering agents. But, have all AF origins been detected? Are all accepted origins, in fact, arrhythmogenic? In order to study these questions and specifically to check our new idea of intermittency as an arrhythmogenesis agent, we chose to employ a mathematical model which was as simple as possible, but which could still be used to observe the basic network processes of AF development. At this point we were not interested in the detailed ionic propagations nor in the actual shapes of the induced action potentials (APs) during the AF outbreaks. The model was checked by its ability to exactly recapture the basic AF developmental stages known from experimental cardiac observations and from more elaborate mathematical models. We use a simple cellular automata 2D mathematical model of N × N matrices to elucidate the field processes leading to AF in a tissue riddled with randomly distributed heterogeneities of different types, under sinus node operation, simulated by an initial line of briefly stimulated cells inducing a propagating wave, and with or without an additional active ectopic action potential pulse, in turn simulated by a transitory operation of a specific cell. Arrhythmogenic contributions, of three different types of local heterogeneities in myocytes and their collaborations, in inducing AF are examined. These are: a heterogeneity created by diffuse fibrosis, a heterogeneity created by myocytes having different refractory periods, and a new heterogeneity type, created by intermittent operation of some myocytes. The developmental stages (target waves and spirals) and the different probabilities of AF occurring under each condition, are shown. This model was established as being capable of reproducing the known AF origins and their basic development stages, and in addition has shown: (1) That diffuse fibrosis on its own is not arrhythmogenic but in combination with other arrhythmogenic agents it can either enhance or limit AF. (2) In general, combinations of het

Topics: Action Potentials; Atrial Fibrillation; Cardiac Conduction System Disease; Cardiovascular Agents; Fibrosis; Heart Atria; Humans; Muscle Cells; Myocytes, Cardiac; Sinoatrial Node

Cardiorenal syndrome (CRS) remains the leading cause of death in hospitalized patients for all disease entities. Sacubitril/Valsartan (Sac/Val) therapy has been proved to improve prognostic outcome in patients with heart failure or chronic kidney disease. This study tested the hypothesis that combined levosimendan and Sac/Val was superior to just one therapy on protecting the heart and kidney against simultaneous heart and kidney ischemia (I) (for 50-min)-reperfusion (R) (for 7-days) (i.e., double IR) injury (defined as CRS).. Adult-male Spraque-Dawley rats (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (double IR), group 3 [double IR+levosimendan (10 mg/kg by intra-peritoneum administration at 30 min/followed by days 1-5 once daily after IR procedure)], group 4 [double IR+Sac/Val (10 mg/kg, orally at 30 min/followed by days 1-5 twice daily after IR procedure)], and group 5 (double IR+Sac/Val+levosimendan). By day 7 after double-IR, the left-ventricular-ejection fraction (LVEF)/left-ventricular-fraction-shortening (LVFS) were highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but they showed no difference between groups 3/4, whereas the circulatory heart-failure (brain-natriuretic peptide)/proinflammatory (suppression of tumorigenicity-2) biomarkers, blood-urea-nitrogen/creatinine and ratio of urine protein to creatinine (all p < 0.0001) exhibited an opposite pattern of LVEF among the groups. The protein expressions of inflammatory (tumor necrosis factor-α/interleukin-1ß/matrix metalloproteinase-9)/oxidative-stress (NOX-1/NOX-2/NOX-4)/apoptotic (mitochondrial-Bax/caspase-3/poly-(ADP-ribose)-polymerase)/fibrotic (Smad3/transforming growth factor-ß)/mitochondrial-damaged (cytosolic-cytochrome-C)/myocardial-hypertrophic (ß-MHC) biomarkers in LV myocardium exhibited an opposite pattern of LVEF among the groups (all p < 0.0001). The cellular expressions of inflammatory (CD68)/DNA-damaged (γ-H2AX) biomarkers and infarct/fibrotic areas in LV myocardium and kidney displayed an opposite pattern of LVEF among the groups (all p < 0.0001).. Combined levosimendan and Sac/Val was superior to merely one therapy on protecting the heart and kidney as well as preserving their functions against double IR injury.

Topics: Aminobutyrates; Animals; Apoptosis; Biphenyl Compounds; Cardio-Renal Syndrome; Cardiovascular Agents; Drug Combinations; Fibrosis; Humans; Inflammation; Kidney; Male; Myocardium; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Simendan; Stroke Volume; Valsartan; Ventricular Function, Left

The renin-angiotensin system is involved in the regulation of various heart diseases. The present study aimed to determine the effects of angiotensin (Ang)-(3-7) on cardiac remodeling and its downstream signaling pathways in neonatal rat cardiomyocytes (NRCMs) and neonatal rat cardiac fibroblasts (NRCFs). The administration of Ang-(3-7) alleviated isoprenaline (ISO)-induced cardiac hypertrophy and fibrosis of mice. ISO treatment increased the levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and beta-myosin heavy chain (β-MHC) in NRCMs, and reduced the levels of collagen I, collagen III, fibronectin, and alpha-smooth muscle actin (α-SMA) in NRCFs. These changes were inhibited by Ang-(3-7) administration. The levels of protein kinase A (PKA), phosphorylated phosphatidylinositol-3-kinase (p-PI3K), and phosphorylated protein kinase B (p-Akt) were increased in NRCMs and NRCFs treated with ISO. The increase of PKA, but not p-PI3K or p-Akt was attenuated by Ang-(3-7) treatment in NRCMs. The increases of p-PI3K and p-Akt, but not PKA were reversed by Ang-(3-7) treatment in NRCFs. Treatment with cAMP or PKA overexpression reversed the attenuating effects of Ang-(3-7) on ISO-induced hypertrophy of NRCMs. The administration of PI3K inhibitor or Akt inhibitor alleviated ISO-induced fibrosis of NRCFs. These results indicated that Ang-(3-7) could alleviate cardiac remodeling. The administration of Ang-(3-7) attenuated hypertrophy of NRCMs via inhibiting the cAMP/PKA signaling pathway, and alleviated fibrosis of NRCFs via inhibiting PI3K/Akt signaling pathway.

Topics: Angiotensin II; Animals; Cardiomegaly; Cardiovascular Agents; Cells, Cultured; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Fibrosis; Isoproterenol; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Peptide Fragments; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Signal Transduction; Ventricular Remodeling

Topics: Acyclic Monoterpenes; Aldehydes; Animals; Cardiovascular Agents; Diabetic Cardiomyopathies; Fibrosis; Heart Failure; Male; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor Receptor-1; Ventricular Dysfunction, Left

Many studies have shown the beneficial effects of aconite water-soluble alkaloid extract (AWA) in experimental models of heart disease, which have been ascribed to the presence of aconine, hypaconine, talatisamine, fuziline, neoline, and songorine. This study evaluated the effects of a chemically characterized AWA by chemical content, evaluated its effects in suprarenal abdominal aortic coarctation surgery (AAC)-induced chronic heart failure (CHF) in rats, and revealed the underlying mechanisms of action by proteomics.. Rats were distributed into different groups: sham, model, and AWA-treated groups (10, 20, and 40 mg/kg/day). Sham rats received surgery without AAC, whereas model rats an AWA-treated groups underwent AAC surgery. after 8 weeks, the treatment group was fed AWA for 4 weeks, and body weight was assessed weekly. At the end of the treatment, heart function was tested by echocardiography. AAC-induced chronic heart failure, including myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis, was evaluated in heart tissue and plasma by RT-qPCR, ELISA, hematoxylin and eosin (H&E) staining, Masson's trichrome staining, TUNEL staining, and immunofluorescence staining of α-SMA, Col Ⅰ, and Col Ⅲ. Then, a proteomics approach was used to explore the underlying mechanisms of action of AWA in chronic heart failure.. AWA administration reduced body weight gain, myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis, and rats showed improvement in cardiac function compared to model group. The extract significantly ameliorated the AAC-induced altered expression of heart failure markers such as ANP, NT-proBNP, and β-MHC, as well as fibrosis, hypertrophy markers MMP-2 and MMP-9, and other heart failure-related factors including plasma levels of TNF-α and IL-6. Furthermore, the extract reduced the protein expression of α-SMA, Col Ⅰ, and Col Ⅲ in the left ventricular (LV), thus inhibiting the LV remodeling associated with CHF. In addition, proteomics characterization of differentially expressed proteins showed that AWA administration inhibited left ventricular remodeling in CHF rats via a calcium signaling pathway, and reversed the expression of RyR2 and SERCA2a.. AWA extract exerts beneficial effects in an AAC-induced CHF model in rats, which was associated with an improvement in LV function, hypertrophy, fibrosis, and apoptotic status. These effects may be related to the regulation of calcium signaling by the altered expression of RyR2 and SERCA2a.

Topics: Aconitum; Animals; Apoptosis; Calcium Signaling; Cardiovascular Agents; Chronic Disease; Disease Models, Animal; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Myocytes, Cardiac; Plant Extracts; Rats, Sprague-Dawley; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Solubility; Solvents; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling; Water

Ginsenoside Re, an herbal ingredient from ginseng, has been demonstrated to protect the heart from various cardiovascular diseases. In this study, we investigated the protective effects and mechanisms of ginsenoside Re (Gin-Re) on cardiac function and left ventricular remodeling in a rat model of myocardial infarction (MI). After ligating the left anterior descending coronary artery, Wistar rats were treated with Gin-Re (135 mg/kg) by gavage everyday for 4 weeks. Serological detection showed that Gin-Re significantly inhibited myocardial injury and attenuated oxidative stress in MI rats. Echocardiographic observation showed that Gin-Re significantly improved cardiac function and prevented left ventricular dilatation induced by MI. Pathological observation found that Gin-Re significantly decreased interstitial fibrosis in the left ventricle of MI rats. Compared with the MI group, Gin-Re treatment promoted AMPKα phosphorylation, decreased TGF-β1 expression, and attenuated Smad2/3 activation. After Gin-Re treatment, the phosphorylation of FAK, PI3K p110α, and Akt was enhanced in MI rats, while PI3K p110β showed no difference compared with the MI group. These results indicate that Gin-Re may improve MI-induced cardiac dysfunction and mitigate ventricular remodeling through regulation of the AMPK/TGF-β1/Smad2/3 and FAK/PI3K p110α/Akt signaling pathways.

Topics: AMP-Activated Protein Kinases; Animals; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Focal Adhesion Kinase 1; Ginsenosides; Male; Myocardial Infarction; Myocardium; Oxidative Stress; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats, Wistar; Signal Transduction; Smad Proteins, Receptor-Regulated; Transforming Growth Factor beta1; Ventricular Function, Left; Ventricular Remodeling

Myocardial fibrosis is a hallmark of cardiac remodeling and functionally involved in heart failure development, a leading cause of deaths worldwide. Clinically, no therapeutic strategy is available that specifically attenuates maladaptive responses of cardiac fibroblasts, the effector cells of fibrosis in the heart. Therefore, our aim was to develop novel antifibrotic therapeutics based on naturally derived substance library screens for the treatment of cardiac fibrosis.. Antifibrotic drug candidates were identified by functional screening of 480 chemically diverse natural compounds in primary human cardiac fibroblasts, subsequent validation, and mechanistic in vitro and in vivo studies. Hits were analyzed for dose-dependent inhibition of proliferation of human cardiac fibroblasts, modulation of apoptosis, and extracellular matrix expression. In vitro findings were confirmed in vivo with an angiotensin II-mediated murine model of cardiac fibrosis in both preventive and therapeutic settings, as well as in the Dahl salt-sensitive rat model. To investigate the mechanism underlying the antifibrotic potential of the lead compounds, treatment-dependent changes in the noncoding RNAome in primary human cardiac fibroblasts were analyzed by RNA deep sequencing.. High-throughput natural compound library screening identified 15 substances with antiproliferative effects in human cardiac fibroblasts. Using multiple in vitro fibrosis assays and stringent selection algorithms, we identified the steroid bufalin (from Chinese toad venom) and the alkaloid lycorine (from. We identified the molecules bufalin and lycorine as drug candidates for therapeutic applications in cardiac fibrosis and diastolic dysfunction.

Topics: Amaryllidaceae Alkaloids; Animals; Apoptosis; Bufanolides; Cardiomyopathies; Cardiovascular Agents; Cell Proliferation; Cells, Cultured; Diastole; Disease Models, Animal; Extracellular Matrix; Fibroblasts; Fibrosis; High-Throughput Screening Assays; Humans; Hypertension; Male; Mice, Inbred C57BL; MicroRNAs; Myocardium; Phenanthridines; Rats, Inbred Dahl; Selenoprotein P; Ventricular Function, Left

Background Animal studies demonstrated that serelaxin lessens fibrosis in heart failure. This study assessed its effect on myocardial deformation using cardiac magnetic resonance and elucidated its relationship to gene regulation and histology in a mouse heart failure model. Methods and Results C57BL/6J mice were subjected to SHAM (n=4) or transverse aortic constriction (TAC). At week 10, TAC mice were randomized to receive either serelaxin (0.5 mg/kg per day; n=11) or vehicle (n=13) for 4 weeks. Cardiac magnetic resonance imaging was performed at baseline and repeated at the end of the study (week 14). Cine images were used to calculate left ventricular (LV) global longitudinal, circumferential, and radial strain. Hearts were examined for histology and gene expression. Compared with SHAM, mice 10 weeks after TAC showed increased LV mass with significant decreases in LV deformation parameters, indicating subclinical deterioration of myocardial function. At week 14, TAC mice given serelaxin demonstrated significant improvements in all LV strain parameters and no decrease in LV stroke volume and ejection fraction compared with TAC mice given vehicle. A significant positive correlation between global circumferential strain and the extent of myocardial fibrosis was found, and global circumferential strain correlated significantly with the expression of heart failure genes in serelaxin-treated mice. Conclusions Serelaxin improved cardiac magnetic resonance-derived myocardial deformation parameters as well as histomorphometric and gene expression findings in mice with heart failure. Cardiac magnetic resonance-derived myocardial mechanics correlate with histology and gene expression, stressing its utilization in myocardial remodeling.

Topics: Animals; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Heart Failure; Magnetic Resonance Imaging, Cine; Male; Mice, Inbred C57BL; Myocardium; Relaxin; Ventricular Function, Left; Ventricular Remodeling

The plant Anchusa italica Retz. (Anchusa azurea Mill.) has been traditionally used in Uygur medicine for the treatment of cardiovascular and cerebrovascular diseases in China. Our previous study showed that total flavonoids from Anchusa italica Retz. (TFAI) exhibited potent cardioprotection in acute ischemia/reperfusion injured rats.. This study was undertaken to investigate the effects of TFAI on chronic myocardial infarction (MI) in mice and the underlying mechanism.. Total flavonoids were extracted from the whole herb of Anchusa italica Retz. and were characterized using HPLC-MS analysis. The left anterior descending branch of the coronary artery was ligated to simulate MI injury in mice. After surgery, mice were orally fed with TFAI at the doses of 10, 30 and 50 mg/kg body weight/day for a total of four weeks. Cardiac function and infarct size were measured, and inflammatory mediators were detected. Hematoxylin and eosin (H&E) staining and Masson's trichrome staining were performed on heart sections. The apoptotic factors, such as Bax, Bcl-2 and cleaved caspase 3, as well as the key proteins in the PI3K/Akt/mTOR signaling pathway were examined by Western blot.. The content of total flavonoids in TFAI was 56.2%. Four weeks following the MI surgery, TFAI enhanced the survival rate in post-MI mice. TFAI treatment at the doses of 30 and 50 mg/kg remarkably reduced infarct size and improved cardiac function as indicated by elevated EF and FS. Assay of the inflammatory factors showed that sera levels of TNF-α, IL-1β and IL-6 were markedly decreased by TFAI treatment compared to the MI group. H&E staining and Masson's trichrome staining demonstrated that TFAI suppressed myocyte hypertrophy and cardiac fibrosis as indicated by the decreased cross-section area and collagen volume. Western blot analysis showed that cleaved caspase 3 and Bax/Bcl-2 were significantly downregulated following TFAI treatment. Furthermore, TFAI treatment significantly suppressed the activation of the PI3K/Akt/mTOR signaling pathway.. Our data suggest that TFAI exerts a potent protective effect against chronic MI injury, and its beneficial effects on cardiac function and cardiac remodeling might be attributable, at least in part, to anti-inflammation and inhibition of the PI3K/Akt/mTOR signaling pathway.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Apoptosis Regulatory Proteins; Boraginaceae; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Flavonoids; Inflammation Mediators; Male; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Phosphatidylinositol 3-Kinase; Plant Extracts; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases; Ventricular Function, Left; Ventricular Remodeling

Obesity-induced cardiomyopathy involves chronic and sustained inflammation. The toll-like receptor 4 (TLR4) signaling pathway can associate innate immunity with obesity. Myeloid differentiation primary response 88 (MyD88), an indispensable downstream adaptor molecule of TLR4, has been reported to mediate obesity complications. However, whether inhibition of MyD88 can mitigate obesity-induced heart injury remains unclear. LM8, a new MyD88 inhibitor, exhibits prominent anti-inflammatory activity in lipopolysaccharide-treated macrophages. In this study, the protective effects of LM8 on a high-fat diet (HFD)-induced heart injury were assessed in a mouse model of obesity. As suggested from the achieved results, LM8 treatment alleviated HFD-induced pathological and functional damages of the heart in mice. Meantime, the treatment of mice with LM8 could significantly inhibit myocardial hypertrophy, fibrosis, inflammatory cytokines expression, and inflammatory cell infiltration induced by HFD. Besides, LM8 administration inhibited the formation of MyD88/TLR4 complex, phosphorylation of ERK, and activation of nuclear factor-κB induced by HFD. According to the achieved results, MyD88 inhibitor LM8 ameliorated obesity-induced heart injury by inhibiting MyD88-ERK/nuclear factor-κB dependent cardiac inflammatory pathways. Furthermore, targeting MyD88 might be a candidate of a therapeutic method to treat obesity-induced heart injury.

Topics: Animals; Cardiomegaly; Cardiomyopathies; Cardiovascular Agents; Cells, Cultured; Cytokines; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Fibrosis; Male; Mice, Inbred C57BL; Myeloid Differentiation Factor 88; Myocarditis; Myocytes, Cardiac; NF-kappa B; Obesity; Signal Transduction; Toll-Like Receptor 4

Coronary microvascular dysfunction combined with maladaptive cardiomyocyte morphology and energetics is a major contributor to heart failure advancement. Thus, dually enhancing cardiac angiogenesis and targeting cardiomyocyte function to slow, or reverse, the development of heart failure is a logical step towards improved therapy. We present evidence for the potential to repurpose a former anti-cancer Arg-Gly-Asp (RGD)-mimetic pentapeptide, cilengitide, here used at low doses. Cilengitide targets αvβ3 integrin and this protein is upregulated in human dilated and ischaemic cardiomyopathies. Treatment of mice after abdominal aortic constriction (AAC) surgery with low-dose cilengitide (ldCil) enhances coronary angiogenesis and directly affects cardiomyocyte hypertrophy with an associated reduction in disease severity. At a molecular level, ldCil treatment has a direct effect on cardiac endothelial cell transcriptomic profiles, with a significant enhancement of pro-angiogenic signalling pathways, corroborating the enhanced angiogenic phenotype after ldCil treatment. Moreover, ldCil treatment of Angiotensin II-stimulated AngII-stimulated cardiomyocytes significantly restores transcriptomic profiles similar to those found in normal human heart. The significance of this finding is enhanced by transcriptional similarities between AngII-treated cardiomyocytes and failing human hearts. Taken together, our data provide evidence supporting a possible new strategy for improved heart failure treatment using low-dose RGD-mimetics with relevance to human disease. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Topics: Angiotensin II; Animals; Cardiomegaly; Cardiovascular Agents; Case-Control Studies; Cells, Cultured; Disease Models, Animal; Drug Repositioning; Fibrosis; Gene Expression Regulation; Heart Failure; Humans; Integrin alphaVbeta3; Male; Mice; Myocytes, Cardiac; Neovascularization, Physiologic; Recovery of Function; Signal Transduction; Snake Venoms; Transcriptome

Heart failure-associated morbidity and mortality is largely attributable to extensive and unregulated cardiac remodelling. Roselle (Hibiscus sabdariffa) calyces are enriched with natural polyphenols known for antioxidant and anti-hypertensive effects, yet its effects on early cardiac remodelling in post myocardial infarction (MI) setting are still unclear. Thus, the aim of this study was to investigate the actions of roselle extract on cardiac remodelling in rat model of MI. Male Wistar rats (200-300 g) were randomly allotted into three groups: Control, MI, and MI + Roselle. MI was induced with isoprenaline (ISO) (85 mg/kg, s.c) for two consecutive days followed by roselle treatment (100 mg/kg, orally) for 7 days. Isoprenaline administration showed changes in heart weight to body weight (HW/BW) ratio. MI was especially evident by the elevated cardiac injury marker, troponin-T, and histological observation. Upregulation of plasma levels and cardiac gene expression levels of inflammatory cytokines such as interleukin (IL)-6 and IL-10 was seen in MI rats. A relatively high percentage of fibrosis was observed in rat heart tissues with over-expression of collagen (Col)-1 and Col-3 genes following isoprenaline-induced MI. On top of that, cardiomyocyte areas were larger in heart tissues of MI rats with upregulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) gene expression, indicating cardiac hypertrophy. Interestingly, roselle supplementation attenuated elevation of plasma troponin-T, IL-6, IL10, and gene expression level of IL-10. Furthermore, reduction of cardiac fibrosis and hypertrophy were observed. In conclusion, roselle treatment was able to limit early cardiac remodelling in MI rat model by alleviating inflammation, fibrosis, and hypertrophy; hence, the potential application of roselle in early adjunctive treatment to prevent heart failure.

Topics: Animals; Atrial Natriuretic Factor; Cardiovascular Agents; Collagen Type I; Collagen Type III; Disease Models, Animal; Fibrosis; Heart Ventricles; Hibiscus; Hypertrophy, Left Ventricular; Inflammation Mediators; Interleukin-10; Interleukin-6; Isoproterenol; Male; Myocardial Infarction; Myocytes, Cardiac; Natriuretic Peptide, Brain; Rats, Wistar; Troponin T; Ventricular Function, Left; Ventricular Remodeling

Cardiac hypertrophy and heart failure are characterized by increased late sodium current and abnormal Ca. Our study demonstrates that inhibition of late sodium current with ranolazine improves pressure overload-induced cardiac hypertrophy and systolic and diastolic function by restoring Na

Topics: Animals; Calcium; Cardiomegaly; Cardiovascular Agents; Cell Line; Fibrosis; Heart Failure; Hypertension; Male; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; Random Allocation; Ranolazine; Sodium

Although many studies have reported the effects of AT1 receptor on dietary salt overload, the role of AT2 receptor in this model is far from completely elucidated. The present study aimed to better understand the role of AT2 receptor in cardiac structure alterations in response to chronic high salt intake in rats.. Male Wistar rats were fed a normal or high salt diet from weaning until 18 weeks of age. Both groups were subdivided into two groups. Starting at 7 weeks of age, rats were treated with or without compound 21 (0.3 mg/kg/day, n = 16), an AT2 receptor agonist. Metabolics and structural parameters were measured. BP, transverse cardiomyocyte and intersticial fibrose was higher in animals fed with high salt diet compared with normal salt fed animals.. Compound 21 prevented the development of cardiac hypertrophy and fibrosis, reduced the increase in blood pressure and prevented the lower weight gain in animals fed a high salt diet.

Topics: Animals; Blood Pressure; Cardiomegaly; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Hypertension; Male; Myocytes, Cardiac; Rats, Wistar; Receptor, Angiotensin, Type 2; Signal Transduction; Sodium Chloride, Dietary; Sulfonamides; Thiophenes; Ventricular Remodeling; Weight Gain

Recent studies reported that cAMP-binding protein Epac1-deficient mice were protected against various forms of cardiac stress, suggesting that pharmacological inhibition of Epac1 could be beneficial for the treatment of cardiac diseases. To test this assumption, we characterized an Epac1-selective inhibitory compound and investigated its potential cardioprotective properties.. We used the Epac1-BRET (bioluminescence resonance energy transfer) for searching for non-cyclic nucleotide Epac1 modulators. A thieno[2,3-b]pyridine derivative, designated as AM-001 was identified as a non-competitive inhibitor of Epac1. AM-001 has no antagonist effect on Epac2 or protein kinase A activity. This small molecule prevents the activation of the Epac1 downstream effector Rap1 in cultured cells, in response to the Epac1 preferential agonist, 8-CPT-AM. In addition, we found that AM-001 inhibited Epac1-dependent deleterious effects such as cardiomyocyte hypertrophy and death. Importantly, AM-001-mediated inhibition of Epac1 reduces infarct size after mouse myocardial ischaemia/reperfusion injury. Finally, AM-001 attenuates cardiac hypertrophy, inflammation and fibrosis, and improves cardiac function during chronic β-adrenergic receptor activation with isoprenaline (ISO) in mice. At the molecular level, ISO increased Epac1-G protein-coupled receptor kinase 5 (GRK5) interaction and induced GRK5 nuclear import and histone deacetylase type 5 (HDAC5) nuclear export to promote the activity of the prohypertrophic transcription factor, myocyte enhancer factor 2 (MEF2). Inversely, AM-001 prevented the non-canonical action of GRK5 on HDAC5 cytoplasmic shuttle to down-regulate MEF2 transcriptional activity.. Our study represents a 'proof-of-concept' for the therapeutic effectiveness of inhibiting Epac1 activity in cardiac disease using small-molecule pharmacotherapy.

Topics: Animals; Cardiovascular Agents; Cell Death; Chronic Disease; Disease Models, Animal; Fibrosis; G-Protein-Coupled Receptor Kinase 5; Guanine Nucleotide Exchange Factors; HEK293 Cells; Histone Deacetylases; Humans; MEF2 Transcription Factors; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion Injury; Myocytes, Cardiac; Rats; Signal Transduction; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

Puerarin is used to treat cardiovascular diseases due to its anti-inflammatory and antifibrotic effects. However, its mechanism of action in atrial fibroblasts is unknown. In this study, we investigated the autophagy pathway and molecular changes in angiotensin II (AngII)-stimulated atrial fibroblasts in response to puerarin treatment. Atrial fibroblasts were cultured and then subjected to stimulation with AngII and puerarin or other chemical drugs (3-MA, CQ, and SP600125). Quantitative real-time polymerase chain reaction and Western blot experiments were used to quantify the expression levels of mRNA and protein. mCherry-GFP-LC3 adenovirus was applied to reflect the autophagic flux. The results showed aggravating levels of autophagy and collagen deposit in the presence of AngII. Puerarin inhibited autophagy and decreased collagen secretion in a dose-dependent manner in atrial fibroblasts. Furthermore, phosphorylation of JNK was down-regulated in response to puerarin, whereas phosphorylation of Akt and mammalian target of rapamycin (mTOR) was upregulated. Interestingly, reduced autophagy and collagen secretion were observed when the JNK signaling pathway was blocked using SP600125. We also observed upregulation of Akt and mTOR phosphorylation in the presence of SP600125. These results suggest that puerarin exerts its antifibrotic effect in atrial fibroblasts partly through the inhibition of autophagy. Furthermore, the mechanism of action of puerarin in fibroblast autophagy seems to be mediated partly through JNK-Akt-mTOR signaling.

Topics: Angiotensin II; Animals; Autophagy; Cardiovascular Agents; Cells, Cultured; Collagen; Dose-Response Relationship, Drug; Fibroblasts; Fibrosis; Heart Atria; Isoflavones; JNK Mitogen-Activated Protein Kinases; Mice; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Time Factors; TOR Serine-Threonine Kinases

Extracellular matrix (ECM) remodeling is a major pathophysiological process during post-myocardial infarction (MI). The activation, differentiation, and proliferation of cardiac fibroblasts to myofibroblasts regulate the expression of ECM proteins. The signaling by bone morphogenetic protein (BMP-4), an extracellular ligand of the TGF-β family, has recently been identified as an essential pathway in regulating cardiovascular dysfunctions including myocardial fibrosis. Oligomeric proanthocyanidins (OPC) are well known for their cardioprotective activity. The primary aim of the study was to investigate BMP-4-mediated ECM turnover in cardiac fibrosis during isoproterenol-induced post-MI and its downregulation by OPC. Myocardial injury was evaluated by assaying serum markers LDH and CK. Oxidative stress and the enzymatic and nonenzymatic antioxidant levels were assessed to support the cardioprotective nature of OPC. The total collagen level was analyzed by measuring hydroxyproline levels. The ISO-induced group showed a significant decrease in the levels of antioxidants due to severe oxidative stress and increased expression of BMP-4 which reflects the increased expression of MMP 2 and 9 with a concomitant increase and deposition of fibrillary collagens type I and III responsible for the fibrotic scar formation as evidenced in the histological analysis.BMP-4 activation, thus, is strongly associated with cardiac fibrosis which was downregulated upon OPC supplementation. This study provides an evidence supporting the antifibrotic effect of OPC via regulation of BMP-4-mediated ECM turnover and also substantiates the remarkable antioxidant efficacy of OPC against isoproterenol induced severe oxidative stress and subsequent post-MI cardiac fibrosis.

Topics: Animals; Antioxidants; Bone Morphogenetic Protein 4; Cardiovascular Agents; Collagen; Disease Models, Animal; Fibrosis; Isoproterenol; Lipid Peroxidation; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardial Infarction; Myocardium; Oxidative Stress; Proanthocyanidins; Rats, Wistar; Ventricular Function, Left; Ventricular Remodeling

Oxidative stress results in mtDNA damage and contributes to myocardial cell death. mtDNA repair enzymes are crucial for mtDNA repair and cell survival. We investigated a novel, mitochondria-targeted fusion protein (Exscien1-III) containing endonuclease III in myocardial ischemia-reperfusion injury and transverse aortic constriction (TAC)-induced heart failure. Male C57/BL6J mice (10-12 wk) were subjected to 45 min of myocardial ischemia and either 24 h or 4 wk of reperfusion. Exscien1-III (4 mg/kg ip) or vehicle was administered at the time of reperfusion. Male C57/BL6J mice were subjected to TAC, and Exscien1-III (4 mg/kg i.p) or vehicle was administered daily starting at 3 wk post-TAC and continued for 12 wk. Echocardiography was performed to assess left ventricular (LV) structure and function. Exscien1-III reduced myocardial infarct size ( P < 0.01) at 24 h of reperfusion and preserved LV ejection fraction at 4 wk postmyocardial ischemia. Exscien1-III attenuated TAC-induced LV dilation and dysfunction at 6-12 wk post-TAC ( P < 0.05). Exscien1-III reduced ( P < 0.05) cardiac hypertrophy and maladaptive remodeling after TAC. Assessment of cardiac mitochondria showed that Exscien1-III localized to mitochondria and increased mitochondrial antioxidant and reduced apoptotic markers. In conclusion, our results indicate that administration of Exscien1-III provides significant protection against myocardial ischemia and preserves myocardial structure and LV performance in the setting of heart failure. NEW & NOTEWORTHY Oxidative stress-induced mitochondrial DNA damage is a prominent feature in the pathogenesis of cardiovascular diseases. In the present study, we demonstrate the efficacy of a novel, mitochondria-targeted fusion protein that traffics endonuclease III specifically for mitochondrial DNA repair in two well-characterized murine models of cardiac injury and failure.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Cardiovascular Agents; Disease Models, Animal; DNA Damage; DNA, Mitochondrial; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Male; Mice, Inbred C57BL; Mitochondria, Heart; Myocytes, Cardiac; Oxidative Stress; Recombinant Fusion Proteins; Signal Transduction; Stroke Volume; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

Angioplasty with drug-coated balloons (DCBs) using excipients as drug carriers is emerging as a potentially viable strategy demonstrating clinical efficacy and proposing additional compliance for the treatment of obstructive vascular diseases. An attempt is made to develop an improved computational model where attention has been paid to the effect of interstitial flow, that is, plasma convection and internalization of bound drug. The present model is capable of capturing the phenomena of the transport of free drug and its retention, and also the internalization of drug in the process of endocytosis to atherosclerotic vessel of heterogeneous tissue composition comprising of healthy tissue, as well as regions of fibrous cap, fibro-fatty, calcified and necrotic core lesions. Image processing based on an unsupervised clustering technique is used for color-based segmentation of a patient-specific longitudinal image of atherosclerotic vessel obtained from intravascular ultrasound derived virtual histology. As the residence time of drug in a stent-based delivery within the arterial tissue is strongly influenced by convective forces, effect of interstitial fluid flow in case of DCB delivery can not be ruled out, and has been investigated by modeling it through unsteady Navier-Stokes equations. Transport of free drug is modeled by considering unsteady advection-reaction-diffusion process, while the bound drug, assuming completely immobilized in the tissue, by unsteady reaction process. The model also takes into account the internalization of drug through the process of endocytosis which gets degraded by the lysosomes and finally recycled into the extracellular fluid. All the governing equations representing the flow of interstitial fluid, the transport of free drug, the metabolization of free drug into bound phase and the process of internalization along with the physiologically realistic boundary and initial conditions are solved numerically using marker and cell method satisfying necessary stability criteria. Simulated results obtained predict that faster drug transfer promotes rapid saturation of binding sites despite perivascular wash out and the concentrations of all drug forms are modulated by the presence of interstitial flow. Such premier attempt of its kind would certainly be of great help in the optimization of therapeutic efficacy of drug.

Topics: Angioplasty, Balloon; Arteries; Blood Flow Velocity; Cardiovascular Agents; Coated Materials, Biocompatible; Computer Simulation; Endocytosis; Equipment Design; Fibrosis; Humans; Models, Cardiovascular; Necrosis; Peripheral Arterial Disease; Plaque, Atherosclerotic; Regional Blood Flow; Tissue Distribution; Vascular Access Devices

The aim of this study was to investigate whether the underlying plaque type affects the neointimal coverage after drug-eluting stent implantation.. A total of 1793 struts in 22 zotarolimus-eluting stents were assessed using optical coherence tomography imaging within 3 months of implantation. Neointimal coverage was evaluated within 5 mm from each stent edge on cross-sectional optical coherence tomography images at every 1-mm interval. The percentage of struts covered by neointima was compared among the normal segment group, the fibrous plaque group, and the lipid plaque group on the basis of the underlying plaque type.. The percentage of covered strut was significantly lower in the normal segment group than in the fibrous plaque group (35.9±30.2 vs. 57.1±31.0%, P<0.05) and the lipid plaque group (vs. 64.7±23.5%, P<0.01). The neointima was significantly thinner in the normal segment group than in the lipid plaque group (19.0±22.3 vs. 32.0±18.8 μm, P<0.01). The percentage of struts on the normal segment was significantly higher in cross-sections with a ratio of uncovered to total struts per section more than 0.3 than in cross-sections with a ratio up to 0.3 (32.4±31.7 vs. 19.5±33.8%, P<0.01).. Struts on the normal segment were less covered and had thinner neointima than struts on the lipid plaque at the stent edge within 3 months after zotarolimus-eluting stent implantation. Caution should be exercised when implanting longer drug-eluting stents to achieve uniform strut coverage in the early phase.

Topics: Aged; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Vessels; Drug-Eluting Stents; Female; Fibrosis; Humans; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Prosthesis Design; Retrospective Studies; Sirolimus; Time Factors; Tomography, Optical Coherence; Treatment Outcome

The phenotype shifting of vascular smooth muscle cells (VSMCs) was indicated to play a role during the initial stage of atherosclerotic plaque formation by facilitating extracellular matrix deposition. This study was aimed at investigating the involvement of the apoptosis signal-regulating kinase 1 (ASK1) /mitogen-activated protein kinase (MAPK) kinases (MKKs) /p38 MAPK pathway in the advanced glycation end product (AGE) -induced fibrotic response of VSMCs. The effect of the novel ASK1 inhibitor AGI-1067 was also studied.Cultured human coronary smooth muscle cells (HCSMCs) were exposed to AGEs. AGI-1067 and siRNAs silencing mkk3, mkk6, and p38 mapk were used to treat the cells. The activation of MKK3, MKK6, and p38 MAPK was assessed by immunoblotting. Fibrotic response was assessed by the fluorescence immunohistochemistry staining of collagen I and collagen VIII. Activation of immunoprecipitation determined the association of ASK1 and its inhibitor thioredoxin. A kinase assay was used to determine ASK1 activity.AGE incubation significantly activated ASK1, MKK3, and MKK6, which led to activation of p38 MAPK, resulting in upregulated fibrotic response in HCSMCs. However, siRNAs knocking down mkk3, mkk6, and p38 mapk impaired this fibrotic response. AGI-1067 administration not only dramatically inhibited the activation of ASK1/MKKs/p38 MAPK but also suppressed the expression of the downstream proteins, including transforming growth factor-β1, connective tissue growth factor, collagen I, and collagen VIII in HCSMCs exposed to AGEs.The ASK1/MKKs/p38 MAPK pathway was activated by AGEs, leading to the fibrotic response in VSMCs. AGI-1067 reversed this process by maintaining the inactive state of ASK1.

Topics: Blotting, Western; Cardiovascular Agents; Cells, Cultured; Coronary Vessels; Fibrosis; Glycation End Products, Advanced; Humans; Immunoprecipitation; MAP Kinase Kinase 3; MAP Kinase Kinase 6; MAP Kinase Kinase Kinase 5; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; p38 Mitogen-Activated Protein Kinases; Probucol; Signal Transduction

Buchang NaoXinTong (NXT), a Chinese medicine, has been widely used to treat patients with coronary heart disease in China. However, the underlying mechanisms need more elucidations. In this study, we investigated if NXT can inhibit the progression of the established lesions while stabilizing plaques. Apolipoprotein E deficient (apoE(-/-)) mice in 3 groups received following treatment: group 1 was fed a high-fat diet (HFD) for 18 weeks; group 2 was prefed HFD for 12 weeks followed by HFD containing NXT for additional 6 weeks; group 3 was prefed HFD for 8 weeks followed by HFD containing NXT for additional 10 weeks. After treatment, serum and aorta samples were collected and determined lipid profiles, lesions, collagen content, mineralization, and macrophage accumulation in aortic root, respectively. NXT had slight effect on serum lipid profiles but significantly reduced progression of the advanced lesions. In aortic wall, NXT increased smooth muscle cell/collagen content in lesion cap while reducing buried fibrous caps, mineralization, and macrophage accumulation within lesions, which suggests that NXT can stabilize plaques. In addition, NXT increased expression of smooth muscle 22α mRNA while inhibiting expression of matrix metalloproteinase-2 and tumor necrosis factor α mRNA in aortas. Our study demonstrates that NXT can reduce advanced atherosclerosis and enhance the plaque stability in apoE(-/-) mice.

Topics: Actins; Animals; Aorta; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Biomarkers; Cardiovascular Agents; Diet, High-Fat; Disease Models, Animal; Drugs, Chinese Herbal; Fibrosis; Gene Expression Regulation; Genetic Predisposition to Disease; Lipids; Macrophages; Male; Matrix Metalloproteinase 2; Mice, Knockout; Phenotype; Phytotherapy; Plants, Medicinal; Plaque, Atherosclerotic; RNA, Messenger; Rupture, Spontaneous; Time Factors; Tumor Necrosis Factor-alpha

Pulmonary arterial hypertension (PAH) is a fatal disease with limited therapeutic options. Pathophysiological changes comprise obliterative vascular remodelling of small pulmonary arteries, elevated mean pulmonary arterial systolic pressure (PASP) due to elevated resistance of pulmonary vasculature, adverse right ventricular remodelling, and heart failure. Recent findings also indicate a role of increased inflammation and insulin resistance underlying the development of PAH. We hypothesized that treatment of this condition with the peroxisome proliferator-activated receptor-γ (PPARγ) activator pioglitazone, known to regulate the expression of different genes addressing insulin resistance, inflammatory changes, and vascular remodelling, could be a beneficial approach. PAH was induced in adult rats by a single subcutaneous injection of monocrotaline (MCT). Pioglitazone was administered for 2 weeks starting 3 weeks after MCT-injection. At day 35, hemodynamics, organ weights, and -indices were measured. We performed morphological and molecular characterization of the pulmonary vasculature, including analysis of the degree of muscularization, proliferation rates, and medial wall thickness of the small pulmonary arteries. Furthermore, markers of cardiac injury, collagen content, and cardiomyocyte size were analyzed. Survival rates were monitored throughout the experimental period. Pioglitazone treatment improved survival, reduced PASP, muscularization of small pulmonary arteries, and medial wall thickness. Further, MCT-induced right ventricular hypertrophy and fibrosis were attenuated. This was accompanied with reduced cardiac expression of brain natriuretic peptide, as well as decreased cardiomyocyte size. Finally, pulmonary macrophage content and osteopontin gene expression were attenuated. Based on the beneficial impact of pioglitazone, activation of PPARγ might be a promising treatment option in PAH.

Topics: Animals; Arterial Pressure; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Heart Ventricles; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Macrophages, Alveolar; Male; Monocrotaline; Myocytes, Cardiac; Natriuretic Peptide, Brain; Osteopontin; Pioglitazone; PPAR gamma; Pulmonary Artery; Rats, Sprague-Dawley; Thiazolidinediones; Vascular Remodeling; Ventricular Function, Right; Ventricular Remodeling

Topics: Anterior Wall Myocardial Infarction; Cardiovascular Agents; Coronary Angiography; Coronary Artery Disease; Coronary Circulation; Coronary Stenosis; Coronary Vessels; Disease Progression; Drug-Eluting Stents; Endothelium, Vascular; Everolimus; Fibrosis; Hemodynamics; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Models, Cardiovascular; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Stress, Mechanical; Tomography, Optical Coherence

Topics: Animals; Cardiovascular Agents; Clinical Decision-Making; Fibrosis; Heart Failure; Humans; Molecular Targeted Therapy; Myocardium; Myofibroblasts; Patient Selection; Precision Medicine; Proteins; Sulfonamides; Torsemide; Ventricular Remodeling

Different carrier excipients unique to individual drug-coated balloons (DCBs) may influence embolic safety characteristics in peripheral vascular territories through embolization of released particulates. A comparator study of IN.PACT Admiral vs Lutonix 035 balloons in healthy swine was therefore performed to assess which balloon produces more downstream emboli.. Single or overlapping 80-mm IN.PACT and Lutonix 035 DCBs were assessed in the femoral arteries of 21 swine with 28- and 90-day follow-up, with standard balloon angioplasty as a control. Histologic analysis of arterial wall and downstream skeletal muscle and coronary band was performed. This analysis was supported by an analytic measurement of paclitaxel levels.. IN.PACT DCBs demonstrated a more pronounced change in medial wall composition, characterized by a paclitaxel-induced loss of medial smooth muscle cells accompanied by increased proteoglycans. The percentage of sections with arterioles exhibiting paclitaxel-associated fibrinoid necrosis in downstream tissues was higher at 90 days with overlapping IN.PACT DBCs compared with Lutonix 035 DCBs (46.2% [interquartile range, 19.2-57.7] vs 0.0% [0.0-11.5]; P = .01), with similar trends noted for 28-day single and overlapping DCBs. Drug analysis in parallel tissues further confirmed higher paclitaxel concentrations in nontarget tissues for IN.PACT than Lutonix 035 balloons for single and overlapping configurations at both time points. Rare embolic crystalline material was observed in downstream tissues, but only for IN.PACT balloons.. There was more fibrinoid necrosis in tissues treated with IN.PACT DCBs compared with Lutonix DCBs, suggesting increased emboli debris with higher paclitaxel levels.

Topics: Angioplasty, Balloon; Animals; Arterioles; Cardiovascular Agents; Coated Materials, Biocompatible; Coronary Vessels; Embolism; Equipment Design; Femoral Artery; Fibrosis; Models, Animal; Muscle, Skeletal; Necrosis; Neointima; Paclitaxel; Sus scrofa; Time Factors; Vascular Access Devices

Pulmonary hypertension (PH) is a devastating disease characterized by increased pulmonary arterial pressure, which progressively leads to right-heart failure and death. A dys-regulated renin angiotensin system (RAS) has been implicated in the development and progression of PH. However, the role of the angiotensin AT2 receptor in PH has not been fully elucidated. We have taken advantage of a recently identified non-peptide AT2 receptor agonist, Compound 21 (C21), to investigate its effects on the well-established monocrotaline (MCT) rat model of PH.. A single s.c. injection of MCT (50 mg·kg(-1) ) was used to induce PH in 8-week-old male Sprague Dawley rats. After 2 weeks of MCT administration, a subset of animals began receiving either 0.03 mg·kg(-1) C21, 3 mg·kg(-1) PD-123319 or 0.5 mg·kg(-1) A779 for an additional 2 weeks, after which right ventricular haemodynamic parameters were measured and tissues were collected for gene expression and histological analyses.. Initiation of C21 treatment significantly attenuated much of the pathophysiology associated with MCT-induced PH. Most notably, C21 reversed pulmonary fibrosis and prevented right ventricular fibrosis. These beneficial effects were associated with improvement in right heart function, decreased pulmonary vessel wall thickness, reduced pro-inflammatory cytokines and favourable modulation of the lung RAS. Conversely, co-administration of the AT2 receptor antagonist, PD-123319, or the Mas antagonist, A779, abolished the protective actions of C21.. Taken together, our results suggest that the AT2 receptor agonist, C21, may hold promise for patients with PH.

Topics: Angiotensin II; Angiotensin II Type 2 Receptor Blockers; Animals; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Imidazoles; Lung; Male; Monocrotaline; Myocardium; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Pulmonary Fibrosis; Pyridines; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 2; Receptors, G-Protein-Coupled; Signal Transduction; Vascular Remodeling; Ventricular Dysfunction, Right; Ventricular Function, Right; Ventricular Remodeling

Emerging evidence suggested that obstructive sleep apnea (OSA) was independently associated with the development of heart failure. In this study, we explored the influence of chronic OSA on left ventricular structural remodeling in canines, and the potential therapeutical role of metoprolol.. Chronic OSA model was established by stopping the ventilator and closing the airway for 4 h/day apnea-ventilation cycles every other day for 12 weeks while metoprolol (5 mg· kg(-1)· day(-1)) were administered continuously. Norepinephrine concentration was measured by Enzyme Linked Immunosorbent Assay. Transmission electron microscopy, Hematoxylin and eosin, TUNEL and Masson trichrome staining were employed to detect the morphology, apoptosis and fibrosis of cardiomyocytes. Protein expression of apoptosis and fibrosis-related factors including apoptosis-inducing factor (AIF), caspase 3, Bcl-2, Bax, α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and p38 mitogen-activated protein kinase (MAPK) were examined by Western blotting.. Norepinephrine concentration was markedly increased in chronic OSA dogs and reduced by metoprolol. Both the apoptotic ratio and collagen volume fraction were significantly increased in left ventricular myocytes of chronic OSA dogs, and was reversed by metoprolol. Moreover, chronic OSA-induced upregulation of AIF, cleaved caspase 3, Bax, α-SMA, and TGF-β1 as well as downregulation of Bcl-2 was markedly recovered by metoprolol, which was mediated by p38 MAPK.. Metoprolol protects against chronic OSA-induced cardiac apoptosis and fibrosis in left ventricular myocytes of canines, which may provide new potential strategy for drug therapy of OSA.

Topics: Actins; Animals; Apoptosis; Apoptosis Inducing Factor; bcl-2-Associated X Protein; bcl-Associated Death Protein; Cardiovascular Agents; Caspase 3; Disease Models, Animal; Dogs; Fibrosis; Gene Expression Regulation; Heart Ventricles; Humans; Male; Metoprolol; Myocytes, Cardiac; Norepinephrine; p38 Mitogen-Activated Protein Kinases; Sleep Apnea, Obstructive; Transforming Growth Factor beta1; Ventricular Remodeling

Obesity is associated with adverse atherosclerotic cardiovascular events. While various metabolic abnormalities associated with obesity promote plaque formation, the morphological phenotype of atherosclerotic plaque has not been well characterized in the setting of obesity. Frequency-domain optical coherence tomography (FD-OCT) enables in vivo visualization of plaque microstructures associated with vulnerability. We characterized plaque microstructures in obese patients.. FD-OCT imaging was performed in 308 patients with coronary artery disease undergoing percutaneous coronary intervention. Patients were stratified according to the presence or absence of obesity (body mass index > 30 kg/m(2)). Plaques in obese (n = 129) and non-obese (n = 179) patients were compared with regard to clinical characteristics and FD-OCT-derived features of plaque vulnerability.. Obese patients were more likely to be younger (p = 0.01), female (p = 0.01) and have a history of hypertension (p = 0.01). Higher levels of triglyceride (p < 0.0001) and glucose (p = 0.02), whereas a lower level of high-density lipoprotein cholesterol (HDL-C) (p = 0.02) was observed in obese patients. FD-OCT imaging demonstrated thinner fibrous caps (85.3 ± 31.1 vs 110.1 ± 32.4 µm, p = 0.01) and a higher prevalence of thin-cap fibroatheroma (28.8 vs 14.3%, p = 0.01) in obese patients, which remained significant after controlling for differences in clinical characteristics. Achieving a low-density lipoprotein cholesterol (LDL-C) level < 1.8 mmol/l was associated with thicker fibrous caps in obese patients, but only to the level observed in non-obese patients with suboptimal lipid control.. Obese patients harbor more vulnerable plaques in association with atherogenic risk factors. The limited benefit of lipid control suggests the need to adopt novel anti-atherosclerotic strategies in higher-risk patients.

Topics: Aged; Biomarkers; Body Mass Index; Cardiovascular Agents; Coronary Artery Disease; Coronary Vessels; Female; Fibrosis; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lipids; Male; Middle Aged; Obesity; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Predictive Value of Tests; Risk Factors; Tomography, Optical Coherence

The cardiac support device supports the heart and mechanically reduces left ventricular (LV) diastolic wall stress. Although it has been shown to halt LV remodeling in dilated cardiomyopathy, its therapeutic efficacy is limited by its lack of biological effects. In contrast, the slow-release synthetic prostacyclin agonist ONO-1301 enhances reversal of LV remodeling through biological mechanisms such as angiogenesis and attenuation of fibrosis. We therefore hypothesized that ONO-1301 plus a cardiac support device might be beneficial for the treatment of ischemic cardiomyopathy.. Twenty-four dogs with induced anterior wall infarction were assigned randomly to 1 of 4 groups at 1 week postinfarction as follows: cardiac support device alone, cardiac support device plus ONO-1301 (hybrid therapy), ONO-1301 alone, or sham control.. At 8 weeks post-infarction, LV wall stress was reduced significantly in the hybrid therapy group compared with the other groups. Myocardial blood flow, measured by positron emission tomography, and vascular density were significantly higher in the hybrid therapy group compared with the cardiac support device alone and sham groups. The hybrid therapy group also showed the least interstitial fibrosis, the greatest recovery of LV systolic and diastolic functions, assessed by multidetector computed tomography and cardiac catheterization, and the lowest plasma N-terminal pro-B-type natriuretic peptide levels (P < .05).. The combination of a cardiac support device and the prostacyclin agonist ONO-1301 elicited a greater reversal of LV remodeling than either treatment alone, suggesting the potential of this hybrid therapy for the clinical treatment of ischemia-induced heart failure.

Topics: Animals; Anterior Wall Myocardial Infarction; Biomarkers; Cardiomyopathies; Cardiovascular Agents; Chemistry, Pharmaceutical; Combined Modality Therapy; Coronary Circulation; Delayed-Action Preparations; Disease Models, Animal; Dogs; Fibrosis; Heart Ventricles; Heart-Assist Devices; Natriuretic Peptide, Brain; Peptide Fragments; Prostaglandins I; Prosthesis Design; Pyridines; Recovery of Function; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Myocarditis is considered one of the major causes of dilated cardiomyopathy. Hepatocyte growth factor (HGF) has pleiotropic activities that promote tissue regeneration and facilitate functional improvement of injured tissue. We investigated whether the epicardial sustained-release of HGF, using gelatin hydrogel sheets, improves cardiac function in a chronic myocarditis rat model.. Six weeks after Lewis rats were immunized with porcine cardiac myosin to establish autoimmune myocarditis, HGF- or normal saline (NS)-incorporated gelatin hydrogel sheets were applied to the epicardium (G-HGF and G-NS, respectively). At either 2 or 4 weeks after treatment, these were compared with the Control myocarditis group. Cardiac function was evaluated by echocardiography and cardiac catheterization. Development of fibrosis was determined by histological study and expression of transforming growth factor-β1 (TGF-β1). Bax and Bcl-2 levels were measured to evaluate apoptotic activity.. At both points, fractional shortening and end-systolic elastance were higher in the G-HGF group than in the Control and G-NS groups (P < 0.01). Fractional shortening at 2 weeks of each group were as follows: 31.0 ± 0.9%, 24.8 ± 2.7% and 48.6 ± 2.6% (Control, G-NS and G-HGF, respectively). The ratio of the fibrotic area of the myocardium was lower in the G-HGF group than in the Control and G-NS groups at 2 weeks (G-HGF, 8.8 ± 0.9%; Control, 17.5 ± 0.2%; G-NS, 15.6 ± 0.7%; P < 0.01). The ratio at 4 weeks was lower in the G-HGF group than in the G-NS group (10.9 ± 1.4% vs 18.5 ± 1.3%; P < 0.01). The mRNA expression of TGF-β1 in the G-HGF group was lower than in the Control group at 2 weeks (0.6 ± 0.1 vs 1.1 ± 0.2) and lower than that in the G-NS group at 4 weeks (0.7 ± 0.1 vs 1.3 ± 0.2). The Bax-to-Bcl-2 ratios at both points were lower in the G-HGF group than in the Control group.. Sustained-released HGF markedly improves cardiac function in chronic myocarditis rats. The antifibrotic and antiapoptotic actions of HGF may contribute to the improvement. HGF-incorporated gelatin hydrogel sheet can be a new therapeutic modality for myocarditis.

Topics: Animals; Apoptosis; Autoimmune Diseases; bcl-2-Associated X Protein; Cardiac Myosins; Cardiovascular Agents; Chemistry, Pharmaceutical; Chronic Disease; Delayed-Action Preparations; Disease Models, Animal; Drug Carriers; Fibrosis; Gelatin; Gene Expression Regulation; Hepatocyte Growth Factor; Hydrogels; Immunization; Male; Myocardial Contraction; Myocarditis; Myocardium; Rats; RNA, Messenger; Swine; Time Factors; Transforming Growth Factor beta1; Ventricular Function, Left

Inflammatory responses mediate the development of perivascular fibrosis and heart dysfunction induced by hypertension. Complement is an important inflammatory system, and we aimed to evaluate the effect of a specific C5a receptor antagonist (C5aRA), PMX53, on inflammation and perivascular fibrosis in the hypertensive heart of the mouse.. Hypertension was induced by angiotensin II (Ang II) subcutaneously infused at a dose of 1500 ng/kg/min for 7 days. PMX53 was administrated at a dose of 1mg/kg, intraperitoneally 1 day before and daily during Ang II infusion.. Although C5aRA treatment did not affect the elevated blood pressure by Ang II infusion, it reduced cardiomyocyte hypertrophy, cardiac inflammation, and perivascular fibrosis. The mRNA and protein levels of the profibrotic cytokines transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF), as measured by real-time polymerase chain reaction and immunohistochemistry staining, were also attenuated by C5aRA treatment after Ang II infusion.. Our data suggest that inhibition of C5aR could be a potential therapeutic strategy in preventing organ damage in Ang II-induced hypertension.

Topics: Angiotensin II; Animals; Cardiomegaly; Cardiovascular Agents; Collagen; Connective Tissue Growth Factor; Cytokines; Disease Models, Animal; Fibrosis; Hypertension; Mice, Inbred C57BL; Myocardium; Peptides, Cyclic; Receptor, Anaphylatoxin C5a; RNA, Messenger; Time Factors; Transforming Growth Factor beta1; Ventricular Remodeling

Mineralocorticoid receptor(MR) antagonism reduces sudden cardiac death in heart failure, but the underlying mechanism remains poorly understood. Concurrent treatment with an MR antagonist during rapid ventricular pacing (RVP) prevents development of adverse ventricular electrophysiological remodeling, interstitial fibrosis, inflammatory cytokine gene activation, and ventricular tachyarrhythmia inducibility without diminishing the extent of systolic dysfunction. We hypothesized that attenuating preexistent inflammatory pathways and myocardial fibrosis with eplerenone after systolic heart failure is established by rapid pacing can reduce electrical activation delays and arrhythmia vulnerability.. Dogs subjected to RVP for 8 weeks in the absence or presence of eplerenone treatment during the final 4 weeks of pacing were assessed by echocardiography, electrophysiology study,ventricular fibrosis measurements, and inflammatory cytokine mRNA expression analysis. Eplerenone reversed preexistent ventricular activation delays, interstitial fibrosis, inflammatory cytokine (interleukin-6, tumor necrosis factor-α) gene overexpression, and arrhythmia vulnerability in ventricular paced dogs with heart failure. Eplerenone failed to improve left ventricular systolic dysfunction or chamber enlargement. A correlation between severity of fibrosis and ventricular arrhythmia inducibility was found.. MR antagonism regresses rapid pacing-induced electrical delays, inflammatory cytokine gene activation, and fibrosis in heart failure. Ventricular arrhythmia vulnerability in heart failure is correlated with extent of fibrosis and electrical activation delays during premature excitation.

Topics: Action Potentials; Animals; Anti-Inflammatory Agents; Arrhythmias, Cardiac; Cardiac Pacing, Artificial; Cardiovascular Agents; Disease Models, Animal; Dogs; Eplerenone; Fibrosis; Heart Failure; Hypertrophy, Left Ventricular; Inflammation Mediators; Interleukin-6; Male; Mineralocorticoid Receptor Antagonists; Myocardium; Spironolactone; Time Factors; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling

Topics: Angioscopy; Autopsy; Biopsy; Cardiovascular Agents; Coronary Artery Disease; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Fatal Outcome; Fibrosis; Humans; Male; Middle Aged; Neointima; Percutaneous Coronary Intervention; Prosthesis Design; Sirolimus; Tomography, Optical Coherence

Cardiac fibrosis greatly impairs normal heart function post infarction and there is no effective anti-fibrotic drug developed at present. The current therapies for cardiac infarction mainly take effect by eliminating occlusion in coronary artery by thrombolysis drugs, vascular stent grafting or heart bypass operation, which are capable to provide sufficient blood flow for intact myocardium yet showed subtle efficacy in ameliorating fibrosis condition. The advances of in vitro cell/tissue models open new avenues for drug assessment due to the low cost, good controllability and availability as well as the convenience for operation as compared to the animal models. To our knowledge, no proper biomimetic in vitro cardiac fibrosis model has been reported yet. Here we engineered an in vitro cardiac fibrosis model using heart-derived fibroblasts, and the fibrogenesis was recapitulated by patterning the substrate rigidity which mimicked the mechanical heterogeneity of myocardium post-infarction. Various biomarkers for cardiac fibrosis were assayed to validate the biomimicry of the engineered platform. Subsequent addition of Rho-associated protein kinase (ROCK) pathway inhibitor reduced the ratio of myofibroblasts, indicating the feasibility of applying this platform in screening anti-fibrosis drugs.

Topics: Amides; Animals; Cardiovascular Agents; Cell Proliferation; Cells, Cultured; Drug Discovery; Fibrosis; Heart Diseases; Male; Mechanotransduction, Cellular; Mice; Models, Cardiovascular; Myofibroblasts; NIH 3T3 Cells; Pyridines; Rats, Sprague-Dawley

Myocardial fibrosis plays a key role in the pathogenesis of cardiovascular diseases. The chronic pressure overload of the heart activates collagen that leads to its excessive accumulation, fibrosis and cardiac hypertrophy. Myocardial injury is often accompanied by liver damage. These two processes are closely linked. One of the links of this chain is the activation of the renin-angiotensin-aldosterone system (RAAS). There is impressive evidence base for drugs that block the RAAS, and thus break the vicious cycle of cardiovascular continuum. Fibrogenesis is nonspecific process and prospect of drug application affecting the activity of the RAAS may be useful for fibrosis prevention not only for the heart and liver, but also for other organs.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Clinical Trials as Topic; Collagen; Female; Fibrosis; Heart Function Tests; Humans; Liver Cirrhosis; Male; Middle Aged; Myocardium; Renin-Angiotensin System

Among three versions of bioresorbable magnesium scaffolds featuring different paclitaxel-elution kinetics, we determined the best-performing scaffold and compared it with established, paclitaxel-eluting, permanent stents TAXUS Liberté and eucaTAX.. Drug-elution kinetics in magnesium scaffolds were modulated by varying the composition of their bioresorbable poly(lactide-co-glycolide) coating loaded with paclitaxel. A 50:50 ratio of lactide to glycolide, or an 85:15 ratio and either high- or low-molecular-weight polymer was applied in the "50/50", "85/15H", and "85/15L" scaffolds, respectively. Seventy-three magnesium scaffolds (25 50/50, 24 85/15H, 24 85/15L) and 36 control stents (18 TAXUS Liberté, 18 eucaTAX) were implanted in coronary arteries of 50 Yucatan mini-pigs. Angiography, histomorphometry, and histopathology data were acquired at 28, 90 and 180 days. The best-performing magnesium scaffold, 85/15H, was equivalent to TAXUS Liberté and superior to eucaTAX regarding late luminal loss, intimal area, fibrin score, and endothelialisation. Intimal inflammation score was higher in 85/15H than in the control stents at 28 days, but this effect disappeared at later time points.. By selecting suitable paclitaxel-elution kinetics, it was feasible to develop a bioresorbable magnesium scaffold whose efficacy and healing characteristics in a porcine coronary model are comparable with those of established paclitaxel-eluting permanent metallic stents.

Topics: Absorbable Implants; Alloys; Animals; Cardiovascular Agents; Coronary Angiography; Coronary Vessels; Drug-Eluting Stents; Feasibility Studies; Female; Fibrosis; Kinetics; Magnesium; Male; Materials Testing; Models, Animal; Molecular Weight; Neointima; Paclitaxel; Percutaneous Coronary Intervention; Polyglactin 910; Prosthesis Design; Swine; Swine, Miniature

The present study is aimed to investigate the effect of Gualou Xiebai Decoction (GXD) ethanol extract on myocardial fibrosis and clarify the possible mechanism.. Rats with ligated left anterior descending coronary artery were treated with GXD ethanol extract (1.14 g/kg, 2.27 g/kg, 4.53 g/kg) daily via gavage for 4 weeks. Histopathological changes and collagen distribution were evaluated by haematoxylin and eosin and Masson staining. The mRNA levels of Collagen I and Collagen III were detected by real-time PCR. The expressions of TGF-β1, TGFβ receptor (TGFβR)I, TGFβRII, P-Smad2/3 and Smad7 were determined by Western blot.. GXD treatment was significantly reduced the heart weight/body weight ratio (P < 0.05) as well as the left ventricle weight/body weight ratio (P < 0.05). It also significantly alleviated the degree of inflammation, decreased myocardial collagen volume fraction (P < 0.05 ∼ 0.01), together with markedly prevented the upregulations of Collagen I and Collagen III (P < 0.05 ∼ 0.01). Moreover, GXD downregulated expressions of TGF-β1, TGFβRI, TGFβRII, Smad2/3 whereas improved Smad7 expression in the myocardial fibrosis rats.. GXD ameliorates myocardial fibrosis induced by cardiac infarction with ligated left anterior descending coronary artery, the mechanism maybe involve in inhibiting the TGF-β1 signalling pathway.

Topics: Allium; Animals; Cardiovascular Agents; Collagen; Drugs, Chinese Herbal; Fibrosis; Heart Ventricles; Inflammation; Male; Myocardial Infarction; Myocardium; Organ Size; Phytotherapy; Rats; Rats, Wistar; Signal Transduction; Smad Proteins; Smad2 Protein; Smad3 Protein; Smad7 Protein; Transforming Growth Factor beta1; Trichosanthes

This study sought to evaluate vascular drug uptake, distribution and response of second-generation paclitaxel coated balloon (PCB) (Cotavance, MEDRAD Interventional, Indianola, Pennsylvania) and compare it with first-generation technology, containing identical excipient and drug concentration.. Original PCB technologies displayed a heterogeneous deposition of crystalline paclitaxel-iopromide inside the balloon folds, whereas second-generation PCBs consisted of more homogeneous, circumferential coatings.. Paclitaxel tissue uptake was assessed in 20 iliofemoral arteries of a domestic swine. Vascular healing response was assessed in the familial hypercholesterolemic model of iliofemoral in-stent restenosis. Three weeks after bare-metal stent implantation, vascular segments were randomly revascularized with first-generation PCBs (n = 6), second-generation PCBs (n = 6), or plain balloon angioplasty (PBA) (n = 6). At 28 days, angiographic and histological evaluation was performed in all treated segments.. One-hour paclitaxel tissue uptake was 42% higher in the second-generation PCBs (p = 0.03) and resulted in more homogeneous segment-to-segment distribution compared with first-generation PCBs. Both angiography (percentage of diameter stenosis: second-generation 11.5 ± 11% vs. first-generation 21.9 ± 11% vs. PBA 46.5 ± 10%; p < 0.01) and histology (percentage of area stenosis: second-generation 50.5 ± 7% vs. first-generation 54.8 ± 18% vs. PBA 78.2 ± 9%; p < 0.01) showed a decrease in neointimal proliferation in both PCB groups. Histological variance of the percentage of area stenosis was lower in second-generation compared with first-generation PCBs (51.7 vs. 328.3; p = 0.05). The presence of peristrut fibrin deposits (0.5 vs. 2.4; p < 0.01) and medial smooth muscle cell loss (0 vs. 1.7; p < 0.01) were lower in the second-generation compared with first-generation PCBs.. In the experimental setting, second-generation PCB showed a comparable efficacy profile and more favorable vascular healing response when compared to first-generation PCB. The clinical implications of these findings require further investigation.

Topics: Angioplasty, Balloon; Animals; Arterial Occlusive Diseases; Cardiovascular Agents; Cell Proliferation; Coated Materials, Biocompatible; Constriction, Pathologic; Contrast Media; Disease Models, Animal; Equipment Design; Femoral Artery; Fibrosis; Hyperlipoproteinemia Type II; Iliac Artery; Iohexol; Neointima; Paclitaxel; Radiography; Sus scrofa; Tissue Distribution; Vascular Access Devices; Wound Healing

This study evaluated the effect of prostaglandin E1 (PGE1) on the stability of atherosclerotic plaque. A vulnerable plaque model was established in rabbits, using balloon injury combined with a high-cholesterol diet. The rabbits were distributed into a control group, a low-dose PGE1 treatment group, a moderate-dose PGE1 treatment group, a high-dose PGE1 treatment group, and a simvastatin treatment group, with treatments lasting for 4 weeks. At week 13 (at the end of the experiments), atherosclerotic plaque was triggered by injection of Russell's viper venom (Chinese) and histamine. Serological, pathological, immunohistochemical, and gene-expression studies were subsequently performed. PGE1 treatment did not alter serum lipid levels; however, PGE1 dose-dependently increased the thickness of the fibrous caps, and decreased the plaque vulnerability index. The plaque contents of macrophage- and the mRNA levels of monocyte-chemotactic protein-1, matrix metalloproteinase-1, and matrix metalloproteinase-9 were markedly reduced in all of the PGE1 treatment groups, with the high-dose of PGE1 being more effective than the simvastatin treatment. These findings suggest that PGE1 dose-dependently enhances the stability of atherosclerotic plaque. The high-dose of PGE1 presented more protection in terms of inhibiting macrophage accumulation and inflammatory expression in plaque. Our findings suggest a novel drug for the treatment of atherosclerosis.

Topics: Alprostadil; Angioplasty, Balloon; Animals; Anti-Inflammatory Agents; Aorta, Abdominal; Aortic Diseases; Atherosclerosis; Cardiovascular Agents; Chemokine CCL2; Cholesterol, Dietary; Cytokines; Daboia; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Down-Regulation; Fibrosis; Histamine; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation Mediators; Lipid Metabolism; Macrophages; Male; Matrix Metalloproteinase 1; Matrix Metalloproteinase 9; Plaque, Atherosclerotic; Rabbits; RNA, Messenger; Simvastatin; Viper Venoms

Cardiac fibrosis is a hallmark of heart disease and plays a vital role in cardiac remodeling during heart diseases, including hypertensive heart disease. Hexarelin is one of a series of synthetic growth hormone secretagogues (GHSs) possessing a variety of cardiovascular effects via action on GHS receptors (GHS-Rs). However, the role of hexarelin in cardiac fibrosis in vivo has not yet been investigated. In the present study, spontaneously hypertensive rats (SHRs) were treated with hexarelin alone or in combination with a GHS-R antagonist for 5 wk from an age of 16 wk. Hexarelin treatment significantly reduced cardiac fibrosis in SHRs by decreasing interstitial and perivascular myocardial collagen deposition and myocardial hydroxyproline content and reducing mRNA and protein expression of collagen I and III in SHR hearts. Hexarelin treatment also increased matrix metalloproteinase (MMP)-2 and MMP-9 activities and decreased myocardial mRNA expression of tissue inhibitor of metalloproteinase (TIMP)-1 in SHRs. In addition, hexarelin treatment significantly attenuated left ventricular (LV) hypertrophy, LV diastolic dysfunction, and high blood pressure in SHRs. The effect of hexarelin on cardiac fibrosis, blood pressure, and cardiac function was mediated by its receptor, GHS-R, since a selective GHS-R antagonist abolished these effects and expression of GHS-Rs was upregulated by hexarelin treatment. In summary, our data demonstrate that hexarelin reduces cardiac fibrosis in SHRs, perhaps by decreasing collagen synthesis and accelerating collagen degradation via regulation of MMPs/TIMP. Hexarelin-reduced systolic blood pressure may also contribute to this reduced cardiac fibrosis in SHRs. The present findings provided novel insights and underscore the therapeutic potential of hexarelin as an antifibrotic agent for the treatment of cardiac fibrosis.

Topics: Animals; Blood Pressure; Cardiovascular Agents; Collagen Type I; Collagen Type III; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Heart Diseases; Hydroxyproline; Hypertension; Hypertrophy, Left Ventricular; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardium; Oligopeptides; Rats; Rats, Inbred SHR; Rats, Wistar; Receptors, Ghrelin; RNA, Messenger; Time Factors; Tissue Inhibitor of Metalloproteinase-1; Ventricular Dysfunction, Left; Ventricular Function, Left

The present study aimed to investigate differences in plaque morphology and components in between the target coronary artery lesion with and without late-acquired incomplete stent apposition (LISA) using radiofrequency analysis (virtual histology) of intravascular ultrasound data.. Incomplete stent apposition is frequently observed in patients with very late stent thrombosis after sirolimus-eluting stent implantation.. The study group consisted of 70 coronary artery lesions in 43 patients who underwent elective coronary stenting for stable angina pectoris. Virtual histology intravascular ultrasound was performed at the implantation of stent and 12-month follow-up. LISA was defined as a separation of stent struts from the intimal surface of the arterial wall that had not been present at the time of stent implantation. The plaque eccentricity index (EI) was calculated as (lumen radius+maximal plaque thickness)/(lumen radius+minimal plaque thickness).. At 12-month follow-up, LISA occurred in 15 plaques (LISA group). Compared with the non-LISA group, the LISA group had significantly longer stents, a higher EI, smaller amount of fibro-fatty component (7.7±4.2 vs. 12.5±7.0%, P=0.01) and larger amount of necrotic core component (16.6±9.8 vs. 11.1±6.4%, P=0.06). Multivariate logistic regression analysis revealed that amount of necrotic core and plaque EI were independent positive predictors for LISA (odds ratio=1.4, 95% confidence interval=1.1-1.6, P=0.04 and 11.2, 1.9-64.9, P<0.01, respectively).. Plaques with increased amounts of necrotic core and higher eccentricity are associated with subsequent LISA after sirolimus-eluting stent implantation.

Topics: Aged; Cardiovascular Agents; Chi-Square Distribution; Coronary Artery Disease; Coronary Thrombosis; Coronary Vessels; Drug-Eluting Stents; Female; Fibrosis; Humans; Logistic Models; Male; Middle Aged; Multivariate Analysis; Necrosis; Odds Ratio; Percutaneous Coronary Intervention; Plaque, Atherosclerotic; Predictive Value of Tests; Prosthesis Design; Risk Assessment; Risk Factors; Sirolimus; Time Factors; Treatment Outcome; Ultrasonography, Interventional

Regardless of the origin, injury to the heart can result in cardiomyocyte hypertrophy, fibrosis, and cell death. Myocarditis often progresses to dilated cardiomyopathy (DCM), a major cause of heart failure. In our study, we used a rat model of myosin-induced experimental autoimmune myocarditis (EAM), in which the heart transits from an acute phase (inflammatory myocarditis) to a chronic phase (remodeling and DCM). Our objective was to investigate whether T-3999, a novel phenylpyridazinone, can reduce this progression. Four weeks after myosin injection, T-3999 was administered daily to male Lewis rats in two doses (3 and 10 mg/kg, orally). Four weeks later, treatment was terminated; hemodynamic and echocardiographic measurements were performed; hearts were excised for histopathology and estimation of histamine, mRNA, and protein levels. Mortality rate was reduced by drug treatment. T-3999 reduced % fibrosis and tissue collagen III. Profibrotic markers-transforming growth factor-β(1), tumor necrosis factor-α, and galectin-3--were attenuated by treatment. Mast cell density and degranulation, and tissue histamine concentration were also reduced. This indicates an anti-inflammatory effect of the drug in reducing fibrosis. Hypertrophy was reduced as reflected by reduced myocyte diameter and natriuretic peptide expression. T-3999 treatment increased the sarcoendoplasmic reticulum Ca(2+) ATPase 2 protein level and improved several cardiac function parameters. The reduction of the remodeling process and improvement in myocardial function suggest an effect of T-3999 in attenuating ventricular remodeling in post-myocarditis DCM.

Topics: Animals; Autoimmune Diseases; Cardiomyopathy, Dilated; Cardiovascular Agents; Cell Degranulation; Cytokines; Disease Models, Animal; Disease Progression; Fibrosis; Hemodynamics; Histamine Release; Male; Mast Cells; Myocarditis; Myosins; Pyridazines; Rats; Rats, Inbred Lew; Time Factors; Ultrasonography; Ventricular Remodeling

The Impact of Nicorandil in Angina (IONA) trial demonstrated that the use of nicorandil, an anti-anginal drug, reduced future cardiovascular events in patients with stable angina. We hypothesized that nicorandil has beneficial effects on coronary arterial plaque characteristics and atherosclerogenesis.. Preintervention intravascular ultrasound-virtual histology was performed prospectively in 65 consecutive patients with stable angina pectoris. There were no differences in coronary risk factors between the nicorandil (n = 16) and non-nicorandil (n = 49) groups. However, the nicorandil group demonstrated a larger %fibrous tissue (68 ± 10 vs. 62 ± 11%, P = 0.049) and a smaller %necrotic core tissue (11 ± 7 vs. 16 ± 10%, P = 0.049) compared with the non-nicorandil group. Multiple regression analysis showed that %necrotic core tissue (P = 0.045) was negatively and %fibrous tissue (P = 0.026) was positively associated with the use of nicorandil independent of statin use. We also analyzed the effect of nicorandil on atherosclerotic lesion formation in a mouse model of atherosclerosis. Lipid profiles were unaffected, but the area of atherosclerotic lesion and plaque necrosis were significantly reduced following 8-week nicorandil treatment in ApoE-deficient mice fed an atherogenic diet. Nicorandil significantly reduced the expression levels of endoplasmic reticulum stress markers, C/EBP homologous protein (CHOP) and glucose regulated protein/BiP (GRP78) in atherosclerotic lesions. Nicorandil significantly attenuated tunicamycin-induced CHOP upregulation in cultured THP-1 macrophages.. Nicorandil exerts its anti-atherogenic effect by mechanisms different from those of statins. Long-term nicorandil treatment is a potentially suitable second-line prevention therapy for patients with coronary artery disease.

Topics: Administration, Oral; Aged; Aged, 80 and over; Angina Pectoris; Animals; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Cardiovascular Agents; Cells, Cultured; Chi-Square Distribution; Coronary Artery Disease; Cytokines; Disease Models, Animal; Drug Administration Schedule; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endothelial Cells; Fibrosis; Humans; Inflammation Mediators; Japan; Lipids; Logistic Models; Macrophages; Male; Mice; Mice, Knockout; Middle Aged; Molecular Chaperones; Necrosis; Nicorandil; Odds Ratio; Retrospective Studies; Time Factors; Treatment Outcome; Ultrasonography, Interventional

Plasma concentrations of high-density lipoprotein (HDL)-cholesterol correlate inversely with the incidence of myocardial infarction in humans. We investigated the effect of treatment with human apolipoprotein A-I (apoA-I), the principal protein of HDL, on plaque disruption in an animal model.. Seventy apolipoprotein E knockout mice were induced to develop atherosclerotic lesions in the brachiocephalic artery by feeding a high-fat diet for 9 weeks. Mice then received twice-weekly treatment with human apoA-I (8 mg/kg) or vehicle, for 2 weeks. The incidence of acute plaque disruption was reduced by 65% in mice receiving apoA-I (P < 0.01). Plaques in treated mice had a more stable phenotype, with an increase in smooth muscle cell (SMC): macrophage ratio (P = 0.05), principally the consequence of an increase in the number of SMC in plaques. In the fibrous cap, there were reductions in matrix metalloproteinase-13 (-69%, P < 0.0001) and S100A4, a marker of SMC de-differentiation (-60%, P < 0.0001). These results indicate that 2 weeks of treatment with small amounts of human apoA-I produces more stable plaques in a mouse model.. Treatment with apoA-I has the potential to stabilize plaques and prevent plaque rupture in humans.

Topics: Animals; Apolipoprotein A-I; Apolipoproteins E; Atherosclerosis; Brachiocephalic Trunk; Cardiovascular Agents; Cell Dedifferentiation; Cholesterol, HDL; Collagen; Disease Models, Animal; Fibrosis; Humans; Inflammation Mediators; Macrophages; Male; Matrix Metalloproteinase 13; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Plaque, Atherosclerotic; Rupture, Spontaneous; S100 Calcium-Binding Protein A4; S100 Proteins

Cardiomyopathy in Duchenne muscular dystrophy (DMD) is an increasing cause of death in patients. The absence of dystrophin leads to loss of membrane integrity, cell death and fibrosis in cardiac muscle. Treatment of cardiomyocyte membrane instability could help prevent cardiomyopathy.. Three month old female mdx mice were exposed to the β(1) receptor agonist isoproterenol subcutaneously and treated with the non-ionic tri-block copolymer Poloxamer P188 (P188) (460 mg/kg/dose i.p. daily). Cardiac function was assessed using high frequency echocardiography. Tissue was evaluated with Evans Blue Dye (EBD) and picrosirius red staining.. BL10 control mice tolerated 30 mg/kg/day of isoproterenol for 4 weeks while death occurred in mdx mice at 30, 15, 10, 5 and 1 mg/kg/day within 24 hours. Mdx mice tolerated a low dose of 0.5 mg/kg/day. Isoproterenol exposed mdx mice showed significantly increased heart rates (p < 0.02) and cardiac fibrosis (p < 0.01) over 4 weeks compared to unexposed controls. P188 treatment of mdx mice significantly increased heart rate (median 593 vs. 667 bpm; p < 0.001) after 2 weeks and prevented a decrease in cardiac function in isoproterenol exposed mice (Shortening Fraction = 46 ± 6% vs. 35 ± 6%; p = 0.007) after 4 weeks. P188 treated mdx mice did not show significant differences in cardiac fibrosis, but demonstrated significantly increased EBD positive fibers.. This model suggests that chronic intermittent intraperitoneal P188 treatment can prevent isoproterenol induced cardiomyopathy in dystrophin deficient mdx mice.

Topics: Adrenergic beta-Agonists; Analysis of Variance; Animals; Aortic Valve; Blood Pressure; Body Weight; Cardiomyopathies; Cardiovascular Agents; Collagen; Disease Models, Animal; Drug Administration Schedule; Dystrophin; Female; Fibrosis; Heart Rate; Injections, Intraperitoneal; Isoproterenol; Mice; Mice, Inbred mdx; Muscle Strength; Muscle, Skeletal; Muscular Dystrophy, Duchenne; Myocardial Contraction; Myocardium; Poloxamer; Stroke Volume; Time Factors; Ventricular Function, Left; Ventricular Pressure

We previously showed that omega-3 polyunsaturated fatty acids (PUFAs) reduce vulnerability to atrial fibrillation (AF). The mechanisms underlying this effect are unknown.. The purpose of this study was to use a genome-wide approach to identify gene expression profiles involved in a new model of AF vulnerability and to determine whether they were altered by PUFA therapy.. Thirty-six dogs were randomized evenly into three groups. Two groups were paced using simultaneous atrioventricular pacing (SAVP) at 220 bpm for 14 days to induce atrial enlargement, fibrosis, and susceptibility to AF. One group was supplemented with oral PUFAs (850 mg/day) for 21 days, commencing 7 days before the start of pacing (SAVP-PUFAs). The second group received no PUFAs (SAVP-No PUFAs). The remaining dogs were unpaced, unsupplemented controls (CTRL). Atrial tissue was sampled at the end of the protocol. Gene expression was analyzed in four dogs randomly selected from each group (n = 12) via microarray. Results were confirmed with quantitative real-time polymerase chain reaction (RT-PCR) and histology on all 36 dogs.. Microarray or quantitative RT-PCR results showed that SAVP-No PUFAs dogs had significantly increased mRNA levels of protein kinase B (Akt), epidermal growth factor (EGF), JAM3, myosin heavy chain alpha (MHCalpha), and CD99 and significantly decreased levels of Smad6 compared with CTRL dogs. Quantitative RT-PCR showed that PUFA supplementation was associated with significant down-regulation of Akt, EGF, JAM3, MHCalpha, and CD99 levels compared with SAVP-No PUFAs dogs.. The effect of PUFAs on these fibrosis, hypertrophy, and inflammation related genes suggests that, in this model, PUFA-mediated prevention of AF may be due to attenuation of adverse remodeling at the genetic level in response to mechanical stress.

Topics: Animals; Atrial Fibrillation; Atrial Function; Cardiomyopathies; Cardiovascular Agents; Disease Models, Animal; Dogs; Fatty Acids, Omega-3; Fibrosis; Gene Expression; Heart Atria; Hypertrophy; Stress, Mechanical

Growing evidence suggests that arginase misregulation plays a key role in the pathophysiology of essential hypertension. In the present study, we investigated the potential cardiovascular therapeutic effects of a long-term treatment with an arginase inhibitor in adult spontaneously hypertensive rats (SHR) with fully developed hypertension.. Treatment of 25-week-old SHR with the arginase inhibitor N(omega)-hydroxy-nor-L-arginine (nor-NOHA, 40 mg/day for 10 weeks) sustainably reduced systolic blood pressure (-30 mmHg, P < 0.05). The antihypertensive effect of nor-NOHA was associated with changes on mesenteric artery reactivity including the restoration of angiotensin-II-induced contraction and acetylcholine-induced vasodilation to the values of normotensive Wistar Kyoto rats. Both nitric oxide synthase and cyclooxygenase-dependent mechanisms account for the improvement of endothelial function afforded by the arginase inhibitor, which in addition blunted hypertension-induced endothelial arginase I overexpression in mesenteric arteries. Nor-NOHA also prevented the remodelling of aorta as measured by collagen content and media/lumen ratio, and improved the compliance of carotid artery in SHR. Cardiac fibrosis assessed by collagen content of left heart ventricle was reduced by nor-NOHA, with no significant effect on cardiac hypertrophy.. Our results report that a long-term treatment with an arginase inhibitor reduced blood pressure, improved vascular function, and reduced cardiac fibrosis in SHR with fully developed hypertension. These data suggest that arginase represents a promising novel target for pharmacological intervention in essential hypertension.

Topics: Animals; Aorta; Arginase; Arginine; Blood Pressure; Cardiovascular Agents; Carotid Arteries; Collagen; Compliance; Cyclooxygenase 1; Cyclooxygenase 2; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Enzyme Inhibitors; Fibrosis; Heart Diseases; Hypertension; Male; Membrane Proteins; Mesenteric Arteries; Myocardium; Nitric Oxide Synthase; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Time Factors; Vasoconstriction; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents

The matrix metalloproteinases (MMPs) play a key role during cardiac remodeling. The aim of the study was to investigate the changes in collagenous proteins and MMPs in the model of non-ischemic, anthracycline-induced chronic cardiomyopathy in rabbits using both biochemical and histological approaches. The study was carried out in three groups of Chinchilla male rabbits: 1) daunorubicin (3 mg/kg, once weekly for 10 weeks), 2) control (saline in the same schedule), 3) daunorubicin with the cardioprotectant dexrazoxane (60 mg/kg, before each daunorubicin). Morphological changes in the myocardium of daunorubicin-treated animals were characterized by focal myocardial interstitial fibrosis of different intensity. The subsequent proliferation of the fibrotic tissue was marked by an increased content of both collagen types I and III, which resulted in their typical coexpression in the majority of bundles of fibers forming either smaller or larger scars. Biochemical analysis showed a significantly increased concentration of hydroxyproline, mainly in the pepsin-insoluble fraction of collagenous proteins, in the daunorubicin-treated group (1.42+/-0.12 mg/g) as compared with the control (1.03+/-0.04 mg/g) and dexrazoxane (1.07+/-0.07 mg/g) groups. Dexrazoxane co-administration remarkably reduced the cardiotoxic effects of daunorubicin to the extent comparable with the controls in all evaluated parameters. Using zymography, it was possible to detect only a gelatinolytic band corresponding to MMP-2 (MMP-9 activity was not detectable). However, no significant changes in MMP-2 activity were determined between individual groups. Immunohistochemical analysis revealed increased MMP-2 expression in both cardiomyocytes and fibroblasts. Thus, this study has revealed specific alterations in the collagen network in chronic anthracycline cardiotoxicity in relationship to the expression and activity of major MMPs.

Topics: Animals; Antibiotics, Antineoplastic; Cardiomyopathies; Cardiovascular Agents; Chronic Disease; Collagen; Daunorubicin; Disease Models, Animal; Drug Interactions; Fibrosis; Hydroxyproline; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardium; Rabbits; Razoxane; Ventricular Remodeling

Cardiac fibroblasts (CFs) regulate myocardial fibrosis and remodeling through proliferation and differentiation. Transforming growth factor-beta1 (TGF-beta1) plays a critical role in the development of myocardial fibrosis after myocardial infarction (MI). The aim of this study was to investigate the effects of inhibiting TGF-beta1 action on myofibroblast differentiation and cardiac function after MI.. CFs were cultured and treated, respectively with PBS, TGF-beta1, soluble TGF-beta1 receptor II (sTbetaRII), and TGF-beta1 plus sTbetaRII. Proliferation CFs were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Myofibroblast differentiation was examined by alpha-smooth muscle actin immunostaining. Expression of P-Smad2 and Smad2/3 was determined by immunostaining and western blot analysis. Four days after ligation of left anterior descending coronary artery, sTbetaRII was injected into injured heart. Two weeks after sTbetaRII administration, myofibroblast differentiation was measured with alpha-smooth muscle actin immunostaining. Four weeks after sTbetaRII administration, cardiac function was evaluated by hemodynamic measurements. Weight parameters, infarct size, and collagen fiber were detected with an earlier experimental method.. Compared with TGF-beta1, TGF-beta1 plus sTbetaRII significantly decreased cell proliferation, myofibroblast differentiation, and expression of P-Smad2 in CFs (P<0.05). Two weeks after sTbetaRII administration, myofibroblast differentiation in MI rats treated with sTbetaRII was reduced compared with MI group (P<0.05). Four weeks after sTbetaRII administration, MI rats that received sTbetaRII showed significantly higher cardiac function and lower in weight parameters, infarct size, and collagen fiber than that of MI group (P<0.05).. sTbetaRII could inhibit TGF-beta1-induced myofibroblast differentiation, alleviate myocardial fibrosis and remodeling, and improve ischemic cardiac function after MI.

Topics: Actins; Animals; Animals, Newborn; Blotting, Western; Cardiovascular Agents; Cell Differentiation; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Fibrosis; Immunohistochemistry; Microinjections; Myocardial Infarction; Myocardium; Myofibroblasts; Phosphorylation; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Recovery of Function; Smad2 Protein; Smad3 Protein; Time Factors; Transforming Growth Factor beta1; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

The adaptive changes that develop in the pressure-overloaded left ventricular myocardium include cardiac hypertrophy and interstitial fibrosis. The objectives of the present study were to evaluate the effects of Tanshinone II-A, a bioactive diterpene quinone isolated from Danshen, on cardiac fibrosis and collagen metabolism in rats with renovascular hypertension. Male Sprague-Dawley rats were subjected to two-kidney two-clip (2K2C) or sham operation (sham) and treated with Valsartan (Val, 26.7 mg/kg/d), Tanshinone II-A (Tsn, 70, 35 mg/kg/d) or vehicle. Six weeks later, systolic blood pressure (BP), LV weight, collagen abundance, cardiac function parameters, hydroxyproline content and mRNA levels of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were evaluated. Both high-dose (Tsn-H, 70 mg/kg/d) and low-dose (Tsn-L, 35 mg/kg/d) of Tsn failed to attenuate 2K2C-induced BP elevation but significantly attenuated the attendant interstitial fibrosis. Val suppressed elevations of BP and left ventricular systolic pressure (LVSP) in 2K2C rats. Val and Tsn-H exerted comparable suppressive effects on the gene expression of MMP-9 and TIMP-1, while Val decreased the MMP-2 mRNA level without affecting the transcript levels of TIMP-2. Both Val and Tsn-H attenuated cardiac dysfunction, while Tsn-L showed slight improvement. These data demonstrate for the first time, that Tsn prevented cardiac fibrosis and improved cardiac function in a rat model of renovascular hypertensive independent of hypotensive effect. Tsn conferred its beneficial effects on the collagen metabolism probably through its regulation of transcript levels of the MMPs/TIMPs balance.

Topics: Abietanes; Animals; Blood Pressure; Cardiovascular Agents; Collagen; Drugs, Chinese Herbal; Fibrosis; Gene Expression; Heart; Hypertension, Renovascular; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocardium; Phytotherapy; Rats; Rats, Sprague-Dawley; RNA, Messenger; Salvia miltiorrhiza; Tetrazoles; Tissue Inhibitor of Metalloproteinase-1; Valine; Valsartan

We investigated whether P144, a synthetic peptide from transforming growth factor-beta(1) (TGF-beta(1)) type III receptor betaglycan, exhibits cardiac antifibrotic properties.. The study was carried out in one group of 10-week-old normotensive Wistar-Kyoto rats treated with vehicle (V-WKY), one group of 10-week-old spontaneously hypertensive rats treated with vehicle (V-SHR), and one group of 10-week-old SHR treated with P144 (P144-SHR) for 12 weeks. Two more groups of 10-week-old untreated WKY and SHR were used to assess baseline values of the parameters tested. In addition, the effects of P144 on rat cardiac fibroblasts stimulated with TGF-beta(1) were also studied. Compared with V-WKY, V-SHR exhibited significant increases in the myocardial expression of phosphorylated Smad2, 38 and 42 kDa connective tissue growth factor (CTGF) isoforms, procollagen alpha1 (I) mRNA, and collagen type I protein, as well as in the expression of lysyl oxidase (LOX) mRNA and protein, collagen cross-linking and deposition. P144 administration was associated with significant reduction in all these parameters in P144-SHR. TGF-beta(1)-stimulated fibroblasts exhibited significant increases in phosphorylated Smad2, 38 and 42 kDa CTGF proteins, and procollagen alpha(1) (I) mRNA compared with control fibroblasts. No significant differences were found in these parameters between fibroblasts incubated with TGF-beta(1) and P144 and control fibroblasts.. These results show that P144 inhibits TGF-beta(1)-dependent signalling pathway and collagen type I synthesis in cardiac fibroblasts. These effects may be involved in the ability of this peptide to prevent myocardial fibrosis in SHR.

Topics: Animals; Blood Pressure; Cardiomyopathies; Cardiovascular Agents; Cell Line; Collagen Type I; Collagen Type I, alpha 1 Chain; Connective Tissue Growth Factor; Disease Models, Animal; Fibroblasts; Fibrosis; Hypertension; Injections, Intraperitoneal; Male; Myocardium; Peptide Fragments; Protein-Lysine 6-Oxidase; Proteoglycans; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Transforming Growth Factor beta; RNA, Messenger; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta1

1. The role of growth hormone (GH) in cardiac remodelling and function in chronic and persistent pressure overload-induced left ventricular hypertrophy has not been defined. The aim of the present study was to assess short-term GH treatment on left ventricular function and remodelling in rats with chronic pressure overload-induced hypertrophy. 2. Twenty-six weeks after induction of ascending aortic stenosis (AAS), rats were treated with daily subcutaneous injections of recombinant human GH (1 mg/kg per day; AAS-GH group) or saline (AAS-P group) for 14 days. Sham-operated animals served as controls. Left ventricular function was assessed by echocardiography before and after GH treatment. Myocardial fibrosis was evaluated by histological analysis. 3. Before GH treatment, AAS rats presented similar left ventricular function and structure. Treatment of rats with GH after the AAS procedure did not change bodyweight or heart weight, both of which were higher in the AAS groups than in the controls. After GH treatment, posterior wall shortening velocity (PWSV) was lower in the AAS-P group than in the control group. However, in the AAS-GH group, PWSV was between that in the control and AAS-P groups and did not differ significantly from either group. Fractional collagen (% of total area) was significantly higher in the AAS-P and AAS-GH groups compared with control (10.34 +/- 1.29, 4.44 +/- 1.37 and 1.88 +/- 0.88%, respectively; P < 0.05) and was higher still in the AAS-P group compared with the AAS-GH group. 4. The present study has shown that short-term administration of GH to rats with chronic pressure overload-induced left ventricular hypertrophy induces cardioprotection by attenuating myocardial fibrosis.

Topics: Animals; Aorta; Aortic Diseases; Cardiovascular Agents; Chronic Disease; Constriction, Pathologic; Disease Models, Animal; Echocardiography; Fibrosis; Human Growth Hormone; Hypertrophy, Left Ventricular; Injections, Subcutaneous; Male; Myocardial Contraction; Myocardium; Rats; Rats, Wistar; Recombinant Proteins; Time Factors; Ventricular Function, Left; Ventricular Remodeling

We investigated the effects of iptakalim, a new ATP-sensitive potassium channel (K(ATP)) opener providing endothelial protection, on the progression of cardiac hypertrophy to failure in a rat model of pressure overloading caused by abdominal aortic banding (AAB). Endothelial dysfunction is central to cardiac hypertrophy and failure induced by pressure overload. It would be useful to clarify whether iptakalim could prevent this.. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, evidence of left ventricular hypertrophy (LVH), and transition to heart failure. LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These could be prevented by treatment with iptakalim at daily oral doses of 1, 3, and 9 mg/kg for 6 weeks. Progression to cardiac failure, demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial and B-type natriuretic peptide mRNA, could also be prevented. The downregulated nitric oxide signalling system was enhanced, whereas the upregulated endothelin signalling system was inhibited, resulting in normalization of the balance between these two systems.. Iptakalim protected the endothelium and prevented progression of cardiac hypertrophy to failure induced by a pressure overload.

Topics: Animals; Aorta, Abdominal; Atrial Natriuretic Factor; Blood Pressure; Cardiovascular Agents; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Endothelin-1; Endothelium, Vascular; Fibrosis; Heart Failure; Heart Rate; Hydroxyproline; Hypertension; Hypertrophy, Left Ventricular; KATP Channels; Male; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Propylamines; Rats; Rats, Sprague-Dawley; Signal Transduction; Time Factors; Ventricular Remodeling

Using molecular imaging techniques, we examined interstitial alterations during postmyocardial infarction (MI) remodeling and assessed the efficacy of antiangiotensin and antimineralocorticoid intervention, alone and in combination.. The antagonists of the renin-angiotensin-aldosterone axis restrict myocardial fibrosis and cardiac remodeling after MI and contribute to improved survival. Radionuclide imaging with technetium-99m-labeled Cy5.5 RGD imaging peptide (CRIP) targets myofibroblasts and indirectly allows monitoring of the extent of collagen deposition post-MI.. CRIP was intravenously administered for gamma imaging after 4 weeks of MI in 63 Swiss-Webster mice and in 6 unmanipulated mice. Of 63 animals, 50 were treated with captopril (C), losartan (L), spironolactone (S) alone, or in combination (CL, SC, SL, and SCL), 8 mice received no treatment. Echocardiography was performed for assessment of cardiac remodeling. Hearts were characterized histopathologically for the presence of myofibroblasts and thick and thin collagen fiber deposition.. Acute MI size was similar in all groups. The quantitative CRIP percent injected dose per gram uptake was greatest in the infarct area of untreated control mice (2.30 +/- 0.14%) and decreased significantly in animals treated with 1 agent (C, L, or S; 1.71 +/- 0.35%; p = 0.0002). The addition of 2 (CL, SC, or SL 1.31 +/- 0.40%; p < 0.0001) or 3 agents (SCL; 1.16 +/- 0.26%; p < 0.0001) demonstrated further reduction in tracer uptake. The decrease in echocardiographic left ventricular function, strain and rotation parameters, as well as histologically verified deposition of thin collagen fibers, was significantly reduced in treatment groups and correlated with CRIP uptake.. Radiolabeled CRIP allows for the evaluation of the efficacy of neurohumoral antagonists after MI and reconfirms superiority of combination therapy. If proven clinically, molecular imaging of the myocardial healing process may help plan an optimal treatment for patients susceptible to heart failure.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Captopril; Carbocyanines; Cardiovascular Agents; Disease Models, Animal; Drug Therapy, Combination; Echocardiography; Fibrillar Collagens; Fibroblasts; Fibrosis; Losartan; Mice; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; Myocardium; Oligopeptides; Predictive Value of Tests; Spironolactone; Technetium; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left; Ventricular Remodeling

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Carbocyanines; Cardiovascular Agents; Drug Therapy, Combination; Echocardiography; Fibrillar Collagens; Fibroblasts; Fibrosis; Heart Failure; Humans; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; Myocardium; Oligopeptides; Predictive Value of Tests; Technetium; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left; Ventricular Remodeling

In a 56-year-old lady, a carcinoid tumor of the terminal ileum metastasized to regional lymph nodes, and the liver was removed by hemicolectomy in 2002. Following a history of cutaneous flushing, diarrhea, and bronchoconstriction 3 years later, a somatostatin therapy was instituted. As flushing and diarrhea resolved and levels of urinary excretion of 5-hydoxyindoleacetic acid decreased, shortness of breath was progressive and prompted a cardiac exam. Despite poor resolution, echocardiography revealed a thickening of the tricuspid valves (TK) with reduced mobility along with right atrial (RA) and right ventricular (RV) dilatation. The pulmonary valve was unobtrusive. Magnetic resonance (MR) imaging revealed extensive fibrous tissue extending from the valvular base to the tip of the tricuspid leaflets. Retraction and immobilization of the TK caused a mild stenosis and a large regurgitant flow. Because medical treatment of tricuspid regurgitation was ineffective, the TK was excised and a Hancock 25-mm bioprosthetic valve was implanted. The postoperative course was uncomplicated, and the patient recuperated and resumed normal daily activities.

Topics: Bioprosthesis; Carcinoid Heart Disease; Cardiovascular Agents; Disease Progression; Female; Fibrosis; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Humans; Magnetic Resonance Imaging, Cine; Middle Aged; Predictive Value of Tests; Treatment Outcome; Tricuspid Valve; Tricuspid Valve Insufficiency

Oxidative stress followed by abnormal signalling can play a critical role in the development of long-term, high blood pressure-induced cardiac remodelling in heart failure (HF). Since oxidative stress-induced poly(ADP-ribose)polymerase (PARP) activation and cell death have been observed in several experimental models, we investigated the possibility that inhibition of nuclear PARP improves cardiac performance and delays transition from hypertensive cardiopathy to HF in a spontaneously hypertensive rat (SHR) model of HF.. SHRs were divided into two groups: one received no treatment (SHR-C) and the other (SHR-L) received 5 mg/kg/day L-2286 (PARP-inhibitor) orally for 46 weeks. A third group was a normotensive age-matched control group (CFY) and a fourth was a normotensive age-matched group receiving L-2286 treatment 5 mg/kg/day (CFY+L). At the beginning of the study, systolic function was similar in both CFY and SHR groups. In the SHR-C group at the end of the study, eccentric hypertrophy with poor left ventricular (LV) systolic function was observed, while PARP inhibitor treatment preserved systolic LV function. Due to these favourable changes, the survival rate of SHRs was significantly improved (P < 0.01) by the administration of the PARP inhibitor (L-2286). The PARP inhibitor used did not affect the elevated blood pressure of SHR rats, but moderated the level of plasma-BNP (P < 0.01) and favourably influenced all the measured gravimetric parameters (P < 0.05) and the extent of myocardial fibrosis (P < 0.05). The inhibition of PARP increased the phosporylation of Akt-1/GSK-3beta (P < 0.01), ERK 1/2 (P < 0.01), and PKC epsilon (P < 0.01), and decreased the phosphorylation of JNK (P < 0.05), p-38 MAPK (P < 0.01), PKC pan betaII and PKC zeta/lambda (P < 0.01), and PKC alpha/betaII and delta (P < 0.05).. These data demonstrate that chronic inhibition of PARP induces long-term favourable changes in the most important signalling pathways related to oxidative stress. PARP inhibition also prevents remodelling, preserves systolic function, and delays transition of hypertensive cardiopathy to HF in SHRs.

Topics: Administration, Oral; Animals; Blood Pressure; Cardiovascular Agents; Disease Models, Animal; Disease Progression; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Fibrosis; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heart Failure; Hypertension; Hypertrophy, Left Ventricular; Isoenzymes; JNK Mitogen-Activated Protein Kinases; Male; Myocardium; Natriuretic Peptide, Brain; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Piperidines; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Protein Kinase C; Proto-Oncogene Proteins c-akt; Quinazolines; Rats; Rats, Inbred SHR; Signal Transduction; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Topics: Animals; Cardiovascular Agents; Disease Progression; Endothelin-1; Endothelium, Vascular; Fibrosis; Heart Failure; Hemodynamics; Humans; Hypertension; Hypertrophy, Left Ventricular; KATP Channels; Mice; Myocardium; Nitric Oxide; Propylamines; Signal Transduction; Ventricular Remodeling

Congestive heart failure is a syndrome characterized by decreased cardiac output with consequent neurohormonal activation leading to water and salt retention. This ultimately results in pulmonary and vascular congestion with eventual organ hypoperfusion and death. Often described as a "vicious cycle", congestive heart failure is responsible for more than 40,000 deaths per year in the United States and plays a substantial role in another 250,000 deaths; it takes a financial toll as well, with approximately $34 billion spent each year on the medical care of patients. The key to ending this vicious cycle is applied research. The Department of Cardiology within The Methodist Hospital is conducting research aimed at understanding heart failure and working towards therapies to improve patient care.

Topics: Animals; Cardiology; Cardiovascular Agents; Disease Models, Animal; Fibrosis; Heart Failure; Hospitals; Humans; Mice; Myocytes, Cardiac; Plant Extracts; Texas; Translational Research, Biomedical

We investigated the effect of an erythropoietin (EPO)-gelatin hydrogel drug delivery system (DDS) applied to the heart on myocardial infarct (MI) size, left ventricular (LV) remodelling and function.. Experiments were performed in a rabbit model of MI. The infarct size was reduced, and LV remodelling and function were improved 14 days and 2 months after MI but not at 2 days after MI in the EPO-DDS group. The number of cluster of differentiation 31(CD31)-positive microvessels and the expression of erythropoietin receptor (EPO-R), phosphorylated-Akt (p-Akt), phosphorylated glycogen synthase kinase 3beta (p-GSK-3beta), phosphorylated extracellular signal-regulated protein kinase (p-ERK), phosphorylated signal transducer and activator of transcription 3 (p-Stat3), vascular endothelial growth factor (VEGF), and matrix metalloproteinase-1 (MMP-1) were significantly increased in the myocardium of the EPO-DDS group.. Post-MI treatment with an EPO-DDS improves LV remodelling and function by activating prosurvival signalling, antifibrosis, and angiogenesis without causing any side effect.

Topics: Animals; Blotting, Western; Cardiovascular Agents; Cell Survival; Chemistry, Pharmaceutical; Disease Models, Animal; Dosage Forms; Drug Carriers; Erythropoietin; Fibrosis; Gelatin; Humans; Hydrogels; Immunohistochemistry; Injections, Subcutaneous; Intracellular Signaling Peptides and Proteins; Myocardial Infarction; Myocardium; Neovascularization, Physiologic; Rabbits; Recombinant Proteins; Signal Transduction; Time Factors; Ventricular Function, Left; Ventricular Remodeling

Persistent endoleak and endotension, complications after endovascular aortic repair, may be caused by an unorganized thrombus inside the aneurysm. The experimental study was designed to evaluate the effectiveness of stent grafts (S/Gs) with slow release of basic fibroblast growth factor (bFGF) for the organization.. The S/Gs were constructed of self-expanding Z stent covered with expanded polytetra fluoroethylene graft, and coated with elastin to be able to bind and slowly release bFGF. Five elastin-coated S/Gs with bFGF (bFGF-S/Gs) and without bFGF (C-S/Gs) were placed in the normal canine aorta respectively. The thoracic aortic aneurysm models were surgically created with a jugular vein patch in 12 beagles. S/Gs with six holes, for creating endoleaks, were used in the experiment of aneurysmal repair. The bFGF-S/Gs (n = 6) and C-S/Gs (n = 6) were implanted. The beagles were sacrificed at two weeks after the endovascular procedure and examined histologically.. The bFGF-S/Gs induced six times the intimal proliferation of the C-S/Gs in normal aorta. Twelve animals had successfully created aneurysms, and had endoleaks just after the endovascular procedure. At two weeks after the endovascular procedure, the percentage of fibrous area in the aneurysmal cavity treated with bFGF-S/G (35.7 +/- 4.3%) was significantly greater than C-S/G (13.6 +/- 2.2%) (P < .01).. bFGF-S/Gs are effective for accelerating organization of the aneurysm cavity and developing neointima. Further research on bFGF-S/Gs would clarify the association of endoleaks.

Topics: Animals; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Blood Vessel Prosthesis Implantation; Cardiovascular Agents; Cell Proliferation; Delayed-Action Preparations; Disease Models, Animal; Dogs; Drug-Eluting Stents; Elastin; Feasibility Studies; Fibroblast Growth Factor 2; Fibrosis; Humans; Polytetrafluoroethylene; Prosthesis Design; Recombinant Proteins; Tunica Intima

We describe a patient who presented with typical symptoms of submassive pulmonary embolism associated with newly diagnosed cardiomyopathy. Contrast enhanced computed tomography demonstrated extensive venous thrombosis, and late enhancement cardiovascular magnetic resonance imaging was consistent with dilated cardiomyopathy with midwall fibrosis. We discuss the images and aetiology of the cardiomyopathy.

Topics: Adult; Anticoagulants; Cardiomyopathy, Dilated; Cardiovascular Agents; Fibrosis; Humans; Magnetic Resonance Imaging; Male; Myocardium; Pulmonary Embolism; Tomography, X-Ray Computed; Treatment Outcome; Venous Thrombosis

The enhanced myocardial collagen content, collagen glycation and the resulting advanced glycation end products (AGE) which exhibit the characteristics of increased cross-linking are proposed for the stiffness of myocardium in diabetes. To explore the cardioprotective effect of green tea in diabetes, we study the effect of green tea extract on myocardial collagen characteristics in streptozotocin diabetic rats. The effect of green tea on marker enzymes in serum and cardiac tissues were also assayed to understand the extent of protection. Six weeks after the diabetes induction, diabetic rats were treated with green tea extract [300 mg (kg body weight)(-1)day(-1)] for 4 weeks. AGE were determined by fluorescence assay and cross-linking of collagen by solubility measurement while collagen content was measured by biochemical assay. The activities of aspartate transaminase (AST), lactate dehydrogenase (LDH) and creatine kinase (CPK) were measured by biochemical assay. The increase in blood glucose, glycated hemoglobin and systolic blood pressure in diabetic rats were reduced upon green tea treatment. The activities of AST, LDH and CPK were significantly increased in serum whereas decreased in cardiac tissues in diabetic rats representing the cardiac damage. Administration of green tea to diabetic rats significantly ameliorates these enzyme activities. There was no significant difference in the myocardial collagen content among the experimental rats. A significant (P<0.05) increase in collagen linked Maillard-type fluorescence and decrease in collagen solubility in the myocardium of diabetic rats as compared to control rats (0.955+/-0.02 versus 0.683+/-0.04 and 30+/-1.41 versus 45.17+/-1.17, respectively) indicates the increase in advanced glycation end products formation and degree of collagen cross-linking. Green tea administration to diabetic rats significantly (P<0.05) decreased the fluorescence (0.73+/-0.02) whereas increased the solubility of collagen (41.5+/-1.04) indicating the reduction in advanced glycation end products and collagen cross-linking. The present study reveals that green tea by ameliorating myocardial collagen characteristics may provide a therapeutic option in the treatment of cardiovascular complications of diabetes.

Topics: Animals; Aspartate Aminotransferases; Blood Glucose; Blood Pressure; Caffeine; Camellia sinensis; Cardiovascular Agents; Catechin; Collagen; Creatine Kinase; Diabetes Mellitus, Experimental; Fibrosis; Glycated Hemoglobin; Glycation End Products, Advanced; Glycosylation; Heart Diseases; Hypoglycemic Agents; L-Lactate Dehydrogenase; Maillard Reaction; Male; Myocardium; Plant Extracts; Plant Leaves; Protein Processing, Post-Translational; Rats; Rats, Wistar; Solubility; Spectrometry, Fluorescence

Microvascular dysfunction in hypertrophic cardiomyopathy (HCM) may create an ischemic substrate conducive to sudden death, but it remains unknown whether the extent of hypertrophy is associated with proportionally poorer perfusion reserve. Comparisons between magnitude of hypertrophy, impairment of perfusion reserve, and extent of fibrosis may offer new insights for future clinical risk stratification in HCM but require multiparametric imaging with high spatial and temporal resolution.. Degree of hypertrophy, myocardial blood flow at rest and during hyperemia (hMBF), and myocardial fibrosis were assessed with magnetic resonance imaging in 35 HCM patients (9 [26%] male/26 female) and 14 healthy controls (4 [29%] male/10 female), aged 18 to 78 years (mean+/-SD, 42+/-14 years) with the use of the American Heart Association left ventricular 16-segment model. Resting MBF was similar in HCM patients and controls. hMBF was lower in HCM patients (1.84+/-0.89 mL/min per gram) than in healthy controls (3.42+/-1.76 mL/min per gram, with a difference of -0.95+/-0.30 [SE] mL/min per gram; P<0.001) after adjustment for multiple variables, including end-diastolic segmental wall thickness (P<0.001). In HCM patients, hMBF decreased with increasing end-diastolic wall thickness (P<0.005) and preferentially in the endocardial layer. The frequency of endocardial hMBF falling below epicardial hMBF rose with wall thickness (P=0.045), as did the incidence of fibrosis (P<0.001).. In HCM the vasodilator response is reduced, particularly in the endocardium, and in proportion to the magnitude of hypertrophy. Microvascular dysfunction and subsequent ischemia may be important components of the risk attributable to HCM.

Topics: Adolescent; Adult; Aged; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Contrast Media; Coronary Circulation; Endocardium; Female; Fibrosis; Gadolinium DTPA; Humans; Hyperemia; Image Processing, Computer-Assisted; Magnetic Resonance Angiography; Male; Microcirculation; Middle Aged; Myocardial Ischemia; Myocardium; Rest; Risk; Vasodilation

Topics: Cardiovascular Agents; Chronic Disease; Extracellular Matrix Proteins; Fibrosis; Heart; Heart Failure; Heart Transplantation; Humans; Myocardium; Patient Selection; Waiting Lists

The effects of long-term administration of YM598, a selective endothelin-A antagonist, on improving the exercise tolerance of chronic heart failure model rats were examined using a treadmill exercise loading test. Rats were acclimatized to the treadmill apparatus and the coronary artery was ligated to prepare a myocardial infarction-induced congestive heart failure (CHF) model. Starting 10 days postoperatively, when the acute phase of infarction was over, YM598 was administered orally once daily for approximately 25 weeks at a dose of 1 mg/kg. At weeks 20 and 24 the treadmill test was performed. YM598 prolonged running time, which had been shortened as a result of heart failure. The weights, relative to the body weight, of the left and right ventricles and lungs of surviving rats with CHF were significantly greater than those of sham-operated rats, suggesting hypertrophy of the ventricles and congestion of the lungs. Administration of YM598 markedly reduced ventricular hypertrophy and pulmonary congestion. Examination of cardiac function revealed that, in surviving CHF rats, the peak positive first derivative of left ventricular pressure was significantly lower, and left ventricular end-diastolic pressure, right ventricular systolic pressure and central venous pressure were significantly higher in comparison to sham-operated rats. These data demonstrate that, in rats with CHF, the contractile and diastolic capacity of the left ventricle decreased and pulmonary hypertension and systemic congestion occurred. Long-term administration of YM598 improved left ventricular function of CHF rats to the level of sham-operated rats, and reduced the workload placed on the right side of the heart. Histological examination revealed that long-term treatment with YM598 prevented fibrosis of the surviving left ventricular myocardium. In conclusion, long-term administration of YM598 to rats with CHF improved exercise tolerance and inhibited remodeling of cardiac muscles, leading to marked improvement of cardiac function.

Topics: Administration, Oral; Animals; Cardiomegaly; Cardiovascular Agents; Disease Models, Animal; Endothelin A Receptor Antagonists; Exercise Tolerance; Fibrosis; Heart Failure; Hypertension, Pulmonary; Male; Myocardial Contraction; Myocardial Infarction; Myocardium; Physical Exertion; Pyrimidines; Rats; Rats, Sprague-Dawley; Sulfonamides; Time Factors; Ventricular Function, Left; Ventricular Pressure; Ventricular Remodeling

We have shown earlier that cardiomyocyte apoptosis continues at a high level late after myocardial infarction and contributes to adverse cardiac remodeling. Here we studied whether this process can be inhibited by the vasopeptidase inhibitor omapatrilat, a drug which causes simultaneous inhibition of both angiotensin converting enzyme and neutral endopeptidase. Our hypothesis was that omapatrilat-treated rats would have less cardiomyocyte apoptosis, and less adverse cardiac remodeling compared to rats treated with selective inhibitors of angiotensin converting enzyme, neutral endopeptidase or placebo. Myocardial infarction was produced by ligation of the left anterior descending coronary artery. Rats were randomized to receive omapatrilat, captopril, neutral endopeptidase inhibitor SQ-28603 or vehicle. Rats treated with omapatrilat and captopril had reduced cardiac BNP mRNA levels and less myocardial fibrosis by comparison with the vehicle-treated rats. However, omapatrilat was more effective than captopril in attenuating hypertrophy as measured by relative cardiac weight (3.0+/-0.2 vs. 3.8+/-0.2 mg/g, P<0.01) or by echocardiographically determined left ventricular mass (0.61+/-0.05 vs. 0.83+/-0.06 g, P<0.01). Myocardial apoptosis was elevated both in the infarction border zone (0.129+/-0.017%) and in the remote area (0.035+/-0.005%) still 4 weeks after myocardial infarction. Angiotensin converting enzyme inhibition proved to be important in the prevention of apoptosis since both omapatrilat and captopril reduced the number of apoptotic myocytes whereas selective neutral endopeptidase inhibitor SQ-28603 had no effect. In conclusion, myocardial apoptosis, remaining increased 4 weeks after myocardial infarction, was reduced by angiotensin converting enzyme inhibition. Vasopeptidase inhibition was more effective than selective angiotensin converting enzyme inhibition in preventing adverse cardiac remodeling after myocardial infarction.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Apoptosis; Blood Pressure; Body Weight; Cardiomyopathy, Hypertrophic; Cardiovascular Agents; Fibrosis; Male; Muscle Cells; Myocardial Infarction; Myocardium; Neprilysin; Organ Size; Pyridines; Rats; Rats, Wistar; Thiazepines; Ventricular Remodeling

Vasopeptidase inhibitors possess dual inhibitory actions on neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) and have beneficial effects on cardiac remodeling. However, the contribution of NEP inhibition to their effects is not yet fully understood. To address the role of cardiac NEP inhibition in the anti-remodeling effects of a vasopeptidase inhibitor, we examined the effects of omapatrilat on the development of cardiac remodeling in rats with left coronary artery ligation (CAL) and those on collagen synthesis in cultured fibroblast cells. In vivo treatment with omapatrilat (30 mg/kg/day for 5 weeks) inhibited cardiac NEP activity in rats with CAL, which was associated with a suppression of both cardiac hypertrophy and collagen deposition. In cultured cardiac fibroblasts, omapatrilat (10(-7) to approximately 10(-5) M) inhibited NEP activity and augmented the ANP-induced decrease in [3H]-proline incorporation. ONO-BB, an active metabolite of the NEP selective inhibitor ONO-9902, also augmented the ANP-induced response, whereas captopril, an ACE inhibitor, did not. The angiotensin I-induced increase in [3H]-proline incorporation was prevented by omapatrilat and captopril, but not by ONO-BB. The results suggest that vasopeptidase inhibitor suppressed cardiac remodeling in the setting of chronic heart failure, possibly acting through the direct inhibition of cardiac NEP. Vasopeptidase inhibitors may have therapeutic advantages over the classical ACE and NEP inhibitors alone with respect to the regression of cardiac fibrosis.

Topics: Animals; Cardiovascular Agents; Cells, Cultured; Collagen; DNA; Dose-Response Relationship, Drug; Fibroblasts; Fibrosis; Heart Failure; Male; Neprilysin; Proline; Protease Inhibitors; Pyridines; Rats; Rats, Wistar; Thiazepines; Time Factors; Ventricular Remodeling

The objective of this study was to characterize the effects of exogenous and endogenous (cardiac fibroblast-derived) adenosine on [3H]proline and [3H]leucine incorporation, which are reliable markers of collagen and total protein synthesis, respectively, in rat left ventricular cardiac fibroblasts. Growth-arrested confluent cardiac fibroblast monolayers were stimulated with 2.5% fetal calf serum (FCS) in the presence and absence of adenosine, 2-chloroadenosine (stable adenosine analogue), or modulators of adenosine levels including (1) erythro-9-(2-hydroxy-3-nonyl) adenine (adenosine deaminase inhibitor), (2) dipyridamole (adenosine transport blocker), and (3) iodotubericidin (adenosine kinase inhibitor). All agents inhibited in a concentration-dependent fashion FCS-induced [3H]proline and [3H]leucine incorporation. These effects were blocked by KF17837 (selective A2 antagonist) and 1,3-dipropyl-8-(p-sulfophenyl)xanthine (A1/A2 receptor antagonist) but not by 8-cyclopentyl-1,3-dipropylxanthine (selective A1 antagonist), thus excluding the participation of A1 receptors. The lack of effect of CGS21680 (selective A2A agonist) excluded involvement of A2A receptors, thus suggesting a major role for A2B receptors. Comparisons of the inhibitory potencies of N6-cyclopentyladenosine (selective A1 agonist), 5'-N-ethylcarboxamidoadenosine (A1/A2 agonist), and 5'-N-methylcarboxamidoadenosine (A1/A2 agonist) were consistent with that of an A2B receptor subtype mediating the inhibitory effects. We conclude that adenosine inhibits FCS-induced collagen and total protein synthesis in cardiac fibroblasts via activation of A2B receptors. These studies suggest, but do not prove, that endogenous adenosine may protect against cardiac fibrosis.

Topics: 2-Chloroadenosine; Adenosine; Animals; Cardiovascular Agents; Cell Culture Techniques; Cell Division; Collagen; Fibroblasts; Fibrosis; Heart Ventricles; Male; Myocardial Infarction; Protein Biosynthesis; Proteins; Rats; Rats, Sprague-Dawley; Receptor, Adenosine A2B; Receptors, Purinergic P1