半乳糖凝集素-3在心肌纤维化相关心血管疾病中的研究进展

心肌纤维化是多种心血管疾病发展到一定阶段的共同病理改变。心肌细胞的细胞再生能力有限,其损伤后的主要修复机制即心肌纤维化。心肌纤维化过程中形成瘢痕组织,在维持心脏结构完整性的同时会导致心脏舒张、收缩功能受损,并在损伤修复中持续加重。半乳糖凝集素-3作为心肌纤维化重要调节分子,是延缓或阻断心肌纤维化的新靶标。现总结最近半乳糖凝集素-3在心肌纤维化相关心血管疾病中的研究进展,以期探寻心肌纤维化过程中的治疗靶点。     

中药单体成分抗心肌纤维化的药效物质基础

<正>心肌纤维化(MF)~[1]存在于多种心血管疾病中,可导致心脏正常收缩和舒张的功能受到影响,进而引发心律失常、心力衰竭及心脏猝死等。近年来研究[2]发现MF是高血压、心肌梗死、病毒性心肌炎、动脉粥样硬化、糖尿病、冠心病、心力衰竭等多种心血管疾病发展到一定阶段后共同的病理产物。其作用机制复杂多样,目前尚未明确,可能与肾素-血管紧张素-醛固酮系统、氧化应激、炎性因子、生长因子、冠状动脉内皮功能障碍     

他汀类药物对心脏胶原的影响及其抗纤维化作用

心脏功能不仅取决于心肌细胞本身的舒缩功能，同时还取决于细胞外基质成分，特别是心肌胶原纤维，其不仅具有支持和连接作用，而且在协调心肌力的传递、信息的传导、营养物质的输送等方面具有重要作用。心肌胶原网络的异常将影响心脏的收缩、舒张功能和正常心肌的电生理，还能导致心力衰竭的发生。心肌纤维化是众多心血管疾病的终末期改变，而心脏胶原的异常是心肌纤维化形成的基础，故抑制心脏胶原的增生，逆转心肌纤维化成为改善心血管疾病预后的关键。他汀类药物不仅可以明显改善血脂水平，而且可以通过多种途径和机制来抑制心脏胶原增生和逆转心肌纤维化。已有证据表明他汀类药物可以逆转心肌纤维化。     

过氧化物酶体增殖物激活受体通路与心肌纤维化

多项研究证实,心力衰竭、心肌梗死后通过一系列神经-内分泌途径激活导致左室重塑,发生心脏不良事件。心肌间质重塑在左室重塑过程中发挥着重要的作用。心肌间质纤维化的直接后果是舒张功能减退,最终出现收缩功能障碍,发生心力衰竭;同时与心律失常、心源性猝死的发生密切相关。目前对于心肌纤维化发生、发展机制的认识还处于探索阶段,临床工作中缺乏规范的诊断、评价方法,缺乏有效、系统的药物治疗和干预措施。近年来的研究发现,过氧化物酶体增殖物激活受体(PPARs)通路与心肌纤维化的发生、发展有着密切的关系。因此,干预PPARs通路,可能…     

终末期心力衰竭患者的肌成纤维细胞表型和纤维化的可逆性

<正>心肌间质纤维化通过激活成纤维细胞分化为肌成纤维细胞(myofibroblasts, MyoFb)导致舒张及收缩功能不全,为心力衰竭的重要病理基础。近期临床证据表明,在终末期心力衰竭患者中,心肌间质纤维化是不可逆转的病理过程。本文研究目的为探讨终末期心力衰竭患者的心肌组织中MyoFb的分化程度和细胞表型逆转的潜在性。方法:两种来源获取成纤维细胞:①从因缺血性或扩张性心肌病需心脏移植患者的左心室分离;②从捐献者的心脏中分离。成纤维细胞经体     

瞬时受体电位通道在心脏纤维化中作用的研究进展

心脏纤维化参与多种心脏疾病的发生发展,可导致心脏重塑和功能障碍,最终引起心力衰竭甚至死亡。心脏成纤维细胞异常增殖并分化为心脏肌成纤维细胞以及心脏细胞外基质过度沉积等是心脏纤维化的主要病理基础。瞬时受体电位(TRP)通道是一种非选择性的阳离子通道,主要介导Ca2+内流来调节细胞功能。越来越多的研究表明,在心肌中TRP通道除调控多种生理功能外,同时参与心脏纤维化的发生发展。本文主要对心脏纤维化的发生机制及TRP通道作为治疗心脏纤维化的新靶点进行综述。     

收缩功能保持的心力衰竭

收缩功能保持的心力衰竭(HFpEF)又被称为收缩功能正常的心力衰竭(HFnEF),以往被称为舒张性心力衰竭(DHF).收缩功能障碍一定伴有舒张功能障碍,严重者可引起充盈压增高;而舒张功能障碍也会影响收缩功能,患者可存在左心室壁心肌纵向运动异常[1,2],但心脏整体收缩功能可保持正常或基本正常.影响舒张功能的主要因素是各种原因引起的心肌基质增生和心内膜、心包纤维化等,典型的疾病如高血压、肥厚型心肌病等.当高血压引起左心室向心性重构和肥厚时左心室舒张特性发生变化,左心室松弛和充盈受损即发生舒张功能不全.左心室舒张功能不全常发生在收缩功能改变之前.患者初期可能无症状,一旦出现心力衰竭症状和体征则称之为HFpEF.     

左心室射血分数保留的心力衰竭研究现状

心室的收缩与舒张功能异常均可能使心脏排血量降低并导致心力衰竭。长期以来我们更多关注的是因心室收缩功能障碍所致的心力衰竭,而对于左室收缩功能正常的心力衰竭的病理生理机制以及诊疗策略却所知很少。在临床实践中因心室舒张功能障碍所导致的心力衰竭约占患者总数的50%左右,其预后与收缩性心力衰竭相似,但猝死的发生更为常见。现结合近年来发表的相关文献对其研究现状进行简要总结。     

线粒体ATP敏感钾通道与线粒体自噬对心力衰竭的作用研究

心力衰竭是由心脏的收缩和/或舒张功能发生障碍，导致心室泵血功能受损引起的循环障碍症候群。临床主要表现为呼吸困难、咳嗽和咳痰。心力衰竭是心脏疾病发展的终末阶段，患者预后较差，目前心力衰竭的发病机制尚不完全明确。近年来，许多研究表明线粒体功能障碍与心力衰竭的发生发展密切相关。现对线粒体ATP敏感钾通道以及线粒体自噬对心力衰竭的作用进展进行综述。     

AMPK与心力衰竭发病机制和治疗的研究进展

心力衰竭（heart failure,HF）作为心血管疾病的终末阶段,是一种复杂的临床综合征,主要表现为心脏的收缩和舒张功能障碍。虽然治疗HF的药物在不断更新,但其病死率仍维持在较高水平,因此人们需要不断探索HF新的治疗靶点。近年来的研究表明单磷酸腺苷活化蛋白激酶（AMP-activated protein kinase,AMPK）参与HF的发生发展,可调控HF时的心肌代谢、心肌纤维化、氧化应激等。现对AMPK保护HF的机制及其相关药物的研究进展作一综述。     

Cardiac fibrosis as a cause of diastolic dysfunction

BACKGROUND: Diastolic dysfunction is increasingly recognized as a cause of symptomatic heart failure, including the clinical syndrome congestive heart failure (CHF). Meta-analyses of earlier studies of this disorder suggest 40-50% of patients with congestive heart failure have preserved left ventricular systolic function. Conditions associated with diastolic dysfunction are diverse and most commonly include ischemic cardiomyopathy with previous myocardial infarction(s) and hypertensive heart disease. PATHOPHYSIOLOGY: An underlying histopathologic finding in each of these entities is an adverse accumulation and structural remodeling of the heart's fibrillar collagen matrix expressed as cardiac fibrosis. In ventricular tissue fibrosis serves to impose a viscoelastic burden that compromises all of diastole, including the rate of relaxation, diastolic suction and passive stiffness. Various factors contribute to the abnormal accumulation of this fibrillar matrix. Of particular importance are effector hormones of the renin-angiotensin-aldosterone system. TREATMENT: In experimental studies, pharmacologic interference with each of these circulating hormones, either through ACE inhibition or respective receptor antagonism, proves cardioprotective by preventing fibrosis while preserving diastolic function. Additionally, a regression of established cardiac fibrosis by its presumptive proteolytic digestion induced by ACE inhibition or AT receptor antagonism has been demonstrated. This cardioreparative strategy improves tissue stiffness and suggests diastolic dysfunction is reversible.     

Connective tissue and the heart. Functional significance and regulatory mechanisms

The heart has a three-dimensional extracellular fibrillar collagen scaffolding that normally serves a variety of functions important to tissue integrity and efficiency of muscular systolic pump and diastolic suction pump function (see article by Kovács). An adverse accumulation of extracellular matrix structural protein compromises tissue stiffness and adversely affects myocardial viscoelasticity, this leads to ventricular diastolic and systolic dysfunction. Hormonal factors, such as chronic, inappropriate (relative to dietary salt intake and intravascular volume) elevations in circulating angiotensin II and aldosterone, are accompanied by fibrosis of right and left sides of the heart. Hemodynamic factors regulate cardiac myocyte work and their adaptive hypertrophic growth. The relative contributions of hormonal and hemodynamic factors in regulating growth of muscular and nonmuscular compartments must form the basis for the selection of pharmacologic intervention that will optimize the management of symptomatic heart failure that accompanies hypertensive heart disease and ischemic cardiomyopathy. Cardioprotective strategies that prevent alteration of normal cardiac tissue structure by fibrosis and appearance of abnormal ventricular stiffness (viscoelasticity) are based on negating the generation of these hormones or interfering with their receptor-ligand binding. A regression of established cardiac fibrosis and improvement in abnormal ventricular stiffness is feasible. Experimental and clinical findings with lisinopril in hypertensive heart disease, where cardiac fibrosis and abnormal ventricular stiffness are present, indicate that such cardioreparation should be a targeted objective of pharmacologic intervention. Systematic analysis of this approach using a controlled clinical trial format is warranted. In recognizing the importance of viscoelastic elements in regulating the mechanical behavior of cardiac tissue, and in turn systolic and diastolic ventricular function, a broader tissue compartment based paradigm (ECM versus myocyte) for the management of heart failure emerges.     

Current understanding of fibrosis in genetic cardiomyopathies

Myocardial fibrosis is the excessive deposition of extracellular matrix proteins, including collagens, in the heart. In cardiomyopathies, the formation of interstitial fibrosis and/or replacement fibrosis is almost always part of the pathological cardiac remodeling process. Different forms of cardiomyopathies show particular patterns of myocardial fibrosis that can be considered as distinctive hallmarks. Although formation of fibrosis is initially aimed to be a reparative mechanism, in the long term, on-going and excessive myocardial fibrosis may lead to arrhythmias and stiffening of the heart wall and subsequently to diastolic dysfunction. Ultimately, adverse remodeling with progressive myocardial fibrosis can lead to heart failure. Not surprisingly, the presence of fibrosis in cardiomyopathies, even when subtle, has consistently been associated with complications and adverse outcomes. In the last decade, non-invasive in vivo techniques for visualization of myocardial fibrosis have emerged, and have been increasingly used in research and in the clinic. In this review, we will describe the epidemiology, distribution, and role of myocardial fibrosis in genetic cardiomyopathies, including hypertrophic, dilated, arrhythmogenic, and non-compaction cardiomyopathy, and a few specific forms of genetic cardiomyopathies.     

Cardiac involvement in systemic sclerosis

Systemic sclerosis (SS) can involve the pericardium, myocardium, conduction system, and cardiac valves. The presence of overt clinical signs of cardiac disease is a poor prognostic sign. Clinical manifestations include dyspnea, palpitations, chest pain, syncope, and symptoms of right heart failure. Prevalence of clinically symptomatic pericardial disease is 5-16%. However, ecocardiographic prevalence is 5.4- 41% and at autopsy is 33-77.5%. Patchy fibrosis is the characteristic myocardial finding in SS. Contraction band necrosis is the typical pathological finding. Important complications of fibrosis include left ventricular hypertrophy, as well as systolic and diastolic dysfunction of both ventricles. Early detection of these abnormalities is very important, mainly of the diastolic dysfunction, since it occurs before the systolic dysfunction and can predict important cardiac damage. Association of skeletal myositis with myocardial disease has been described. Patients with skeletal myositis are more likely to develop congestive heart failure, sustained symptomatic arrythmias, and cardiac sudden death. Coronary arteries are normal in systemic sclerosis, but there is no endomyocardial vessel involvement. There is an increased prevalence of arrhytmias, mainly premature atrial and ventricular contractions, as well as conduction system disease. Cardiac valvular involvement is minor in systemic sclerosis; mitral valve is the most frequently affected. Other abnormalities described in this disease include peripheral large vessels stiffness and secondary cardiac involvement due to pulmonary and systemic arterial hypertension. Cardiac involvement confers a high morbi-mortality risk in systemic sclerosis.     

Role of exercise and metabolism in heart failure with normal ejection fraction

Left ventricular dysfunction associated with metabolic disorders has a number of features that might shed light on the integrity of heart failure with normal ejection fraction. First, although these patients may be dyspneic and have a normal ejection fraction, their diastolic dysfunction is not isolated. Both experimental models and sensitive new parameters in humans have shown abnormal systolic function, even though the less sensitive parameters (such as ejection fraction) become abnormal only with stress. Moreover, the mechanistic contributors to myocardial dysfunction, including structural changes and metabolic influences on the cardiac myocyte, interstitial fibrosis, vascular disease, and altered loading, are likely to influence systolic as much as diastolic function. The responses of systolic and diastolic heart failure to exercise training show analogies, particularly with respect to the importance of peripheral adaptation, as well as a similar training response. Together, these features are more supportive of a continuum of pathophysiology between systolic and diastolic heart failure, rather than the 2 representing discreet phenomena.     

Increased connective tissue growth factor relative to brain natriuretic peptide as a determinant of myocardial fibrosis

Excessive fibrosis contributes to an increase in left ventricular stiffness. The goal of the present study was to investigate the role of connective tissue growth factor (CCN2/CTGF), a profibrotic cytokine of the CCN (Cyr61, CTGF, and Nov) family, and its functional interactions with brain natriuretic peptide (BNP), an antifibrotic peptide, in the development of myocardial fibrosis and diastolic heart failure. Histological examination on endomyocardial biopsy samples from patients without systolic dysfunction revealed that the abundance of CTGF-immunopositive cardiac myocytes was correlated with the excessive interstitial fibrosis and a clinical history of acute pulmonary congestion. In a rat pressure overload cardiac hypertrophy model, CTGF mRNA levels and BNP mRNA were increased in proportion to one another in the myocardium. Interestingly, relative abundance of mRNA for CTGF compared with BNP was positively correlated with diastolic dysfunction, myocardial fibrosis area, and procollagen type 1 mRNA expression. Investigation with conditioned medium and subsequent neutralization experiments using primary cultured cells demonstrated that CTGF secreted by cardiac myocytes induced collagen production in cardiac fibroblasts. Further, G protein-coupled receptor ligands induced expression of the CTGF and BNP genes in cardiac myocytes, whereas aldosterone and transforming growth factor-beta preferentially induced expression of the CTGF gene. Finally, exogenous BNP prevented the production of CTGF in cardiac myocytes. These data suggest that a disproportionate increase in CTGF relative to BNP in cardiac myocytes plays a central role in the induction of excessive myocardial fibrosis and diastolic heart failure.     

The role of inflammatory and fibrogenic pathways in heart failure associated with aging

Heart failure is strongly associated with aging. Elderly patients with heart failure often have preserved systolic function exhibiting left ventricular hypertrophy accompanied by a decline in diastolic function. Experimental studies have demonstrated that age-related cardiac fibrosis plays an important role in the pathogenesis of diastolic heart failure in senescent hearts. Reactive oxygen species and angiotensin II are critically involved in fibrotic remodeling of the aging ventricle; their fibrogenic actions may be mediated, at least in part, through transforming growth factor (TGF)-β. The increased prevalence of heart failure in the elderly is also due to impaired responses of the senescent heart to cardiac injury. Aging is associated with suppressed inflammation, delayed phagocytosis of dead cardiomyocytes, and markedly diminished collagen deposition following myocardial infarction, due to a blunted response of fibroblasts to fibrogenic growth factors. Thus, in addition to a baseline activation of fibrogenic pathways, senescent hearts exhibit an impaired reparative reserve due to decreased responses of mesenchymal cells to stimulatory signals. Impaired scar formation in senescent hearts is associated with accentuated dilative remodeling and worse systolic dysfunction. Understanding the pathogenesis of interstitial fibrosis in the aging heart and dissecting the mechanisms responsible for age-associated healing defects following cardiac injury are critical in order to design new strategies for prevention of adverse remodeling and heart failure in elderly patients.     

肠道菌群代谢产物与心肌纤维化关系的研究进展

心肌纤维化(MF)以细胞外基质积聚、成纤维细胞活化、转化为肌成纤维细胞为特征,是心脏损伤后心脏重构的特征之一,MF包括两种基本类型:反应性纤维化和修复性纤维化,在心室重构的过程中,两种纤维化常合并存在,MF可导致充血性心力衰竭、恶性心律失常和猝死,成为心室重构持续发展和难以逆转的重要原因.一些研究表明,肠道菌群代谢产物...     

Aging of myocardial collagen

The objective of this article was to present a review of the collagen tissue of the heart muscle as a function of age. The myocardial collagen matrix consists of a network of fibrillar collagen which is intimately connected to the myocyte. Most collagen fibers reside in parallel with myocytes. These fibers may have a wavy, taut or coiled appearance. Fibrillar collagen types I and III are the major components of the myocardial collagen matrix. Collagen type I has been found to represent nearly 80% of the total collagen protein, while type III collagen is present in lower proportions (approximately 11%). Cardiac fibroblasts are the cellular source of fibrillar collagen, cardiac myocytes expressing only mRNA for type IV collagen. Collagens types I and III exhibit a high tensile strength which plays an important role in the behavior of the ventricle during the cardiac cycle. The collagen concentration and the intermolecular cross-linking of collagen increase with age. Measurements of collagen content in myocardial tissue siggest that it is the type I collagen fibers that increase in number and thickness in the aged. At the same time, electron microscopic observations have shown an increase in the number of collagen fibrils with a large diameter in the aging heart. The mechanism responsible for the myocardial fibrosis in the senescent myocardium is unclear. The collagen deposition in the myocardium could be due to the regulation of collagen byosinthesis at pre-translational levels. It is possible that the regulatory elements involved in this process are growth factors such as TGF-β1 and hormones and neurotransmitters. Details of regulatory mechanism that may come into play during aging may be elucidated by further investigations. The accumulation of collagen within the myocardium increases muscle stiffness. Myocardial function is affected by this process; this is usually reflected by incomplete relaxation during early diastolic filling, and presumably account for the decrease in early left ventricular diastolic compliance. This revised version was published online in July 2006 with corrections to the Cover Date.