Osteopontin-mediated myocardial fibrosis in heart failure: a role for lysyl oxidase?

AIMS: We investigated whether the pro-fibrotic matricellular protein osteopontin (OPN) is associated with the enzymes involved in the extracellular synthesis of fibril-forming collagen type I (i.e. procollagen C-proteinase, PCP) and its cross-linking to form insoluble fibrils (i.e. lysyl oxidase, LOX) in heart failure (HF) of hypertensive origin. METHODS AND RESULTS: OPN, PCP, and LOX were assessed by histochemical and molecular methods in the myocardium of 21 patients with hypertensive heart disease (HHD) and HF. Whereas the myocardial expression of OPN was very scarce in control hearts (n = 10), it was highly expressed in HF patients (P < 0.0001). OPN was directly correlated with LOX (r = 0.460, P = 0.041), insoluble collagen (r = 0.534, P = 0.015), pulmonary capillary wedge pressure (r = 0.558; P = 0.009), and left-ventricular (LV) chamber stiffness (r = 0.458, P = 0.037), and inversely correlated with LV ejection fraction (r = -0.513, P = 0.017) in all patients. OPN did not correlate with PCP and other parameters assessing collagen synthesis by fibroblasts or degradation by matrix metalloproteinases. In vitro studies showed that OPN significantly (P < 0.05) increases the expression and activity of LOX in human cardiac and dermal fibroblasts. CONCLUSION: An excess of OPN is associated with increased LOX and insoluble collagen, as well as with LV stiffness and systolic dysfunction in patients with HHD and HF. In addition, OPN up-regulates LOX in human fibroblasts. It is suggested that the OPN-LOX axis might facilitate the formation of insoluble collagen (i.e. stiff and resistant to degradation) and the subsequent alteration in LV mechanical properties and function in patients with HHD and HF.

Péptido similar al glucagón tipo 1 y supervivencia de la célula cardiaca / Glucagon-like peptide 1 and cardiac cell survival

La activación de diferentes procesos de muerte celular en los cardiomiocitos tras un infarto de miocardio (IM) contribuye al tamaño final del infarto, a la mortalidad subsecuente y al remodelado postinfarto en los supervivientes. Los diversos mecanismos deletéreos activados durante las fases de isquemia y reperfusión en el IM incluyen la privación de oxígeno, la disponibilidad reducida de nutrientes y factores de supervivencia, la acumulación de residuos, la generación de especies reactivas del oxígeno, la sobrecarga de calcio, la infiltración por neutrófilos en el área isquémica, la depleción energética, y la apertura del poro de transición de permeabilidad mitocondrial, todos ellos mecanismos de activación de apoptosis y necrosis en los cardiomiocitos. En los últimos años, las terapias basadas en el péptido similar al glucagón tipo 1 [GLP-1 (7-36) amida] han adquirido mayor relevancia como tratamiento metabólico de la diabetes mellitus tipo 2. Entre las acciones atribuidas a GLP-1 destaca la preservación de la viabilidad en diferentes tipos celulares, entre ellos los cardiomiocitos. Este artículo revisa los principales estudios experimentales que han contribuido a una mayor comprensión de la citoprotección inducida por GLP-1 en el miocardio y de sus efectos en la función cardiaca, ahondando en el estudio de su papel como diana terapéutica, no solo en el contexto de la diabetes mellitus sino también en otras patologías que cursan con remodelado cardiaco (AU)

During myocardial infarction (MI), a variety of mechanisms contribute to activation of cell death processes in cardiomyocytes, which determines the final MI size, subsequent mortality, and post-MI remodeling. The deleterious mechanisms activated during the ischemia and reperfusion phases in MI include oxygen deprival, decreased availability of nutrients and survivalfactors, accumulation of waste products, generation of oxygen free radicals, calcium overload, neutrophil infiltration in the ischemic area, depletion of energy stores, and opening of themitochondrial permeability transition pore, all of them contributing to activation of apoptosis and necrosis in cardiomyocytes. Glucagon-like peptide-1 [GLP-1 (7-36) amide] has gained relevance in recent years for metabolic treatment of patients with type 2 diabetes mellitus. Cytoprotection of different cell types, including cardiomyocytes, is among the pleiotropicactions reported for GLP-1. This paper reviews the most relevant experimental studies that have contributed to a better understanding of the molecular mechanisms and intracellular pathways involved in cardioprotection induced by GLP-1 and analyzes in depth its potential role as a therapeutic target both in the ischemic and reperfused myocardium and in other conditions that are associated with myocardial remodeling and heart failure (AU)

Glucagon-like peptide 1 and cardiac cell survival.

During myocardial infarction (MI), a variety of mechanisms contribute to activation of cell death processes in cardiomyocytes, which determines the final MI size, subsequent mortality, and post-MI remodeling. The deleterious mechanisms activated during the ischemia and reperfusion phases in MI include oxygen deprival, decreased availability of nutrients and survival factors, accumulation of waste products, generation of oxygen free radicals, calcium overload, neutrophil infiltration in the ischemic area, depletion of energy stores, and opening of the mitochondrial permeability transition pore, all of them contributing to activation of apoptosis and necrosis in cardiomyocytes. Glucagon-like peptide-1 [GLP-1 (7-36) amide] has gained relevance in recent years for metabolic treatment of patients with type 2 diabetes mellitus. Cytoprotection of different cell types, including cardiomyocytes, is among the pleiotropic actions reported for GLP-1. This paper reviews the most relevant experimental studies that have contributed to a better understanding of the molecular mechanisms and intracellular pathways involved in cardioprotection induced by GLP-1 and analyzes in depth its potential role as a therapeutic target both in the ischemic and reperfused myocardium and in other conditions that are associated with myocardial remodeling and heart failure.

GLP-1 and cardioprotection: from bench to bedside.

During myocardial infarction (MI), a variety of mechanisms contribute to the activation of cell death processes in cardiomyocytes, determining the final MI size, subsequent mortality, and post-MI remodelling. The deleterious mechanisms accompanying the ischaemic and reperfusion phases in MI include deprivation of oxygen, nutrients, and survival factors, accumulation of waste products, generation of oxygen free radicals, calcium overload, neutrophil infiltration of the ischaemic area, depletion of energy stores, and opening of the mitochondrial permeability transition pore, all of which contribute to the activation of apoptosis and necrosis in cardiomyocytes. During the last few years, glucagon-like peptide-1 (GLP-1) (7-36)-based therapeutic strategies have been incorporated into the treatment of patients with type 2 diabetes mellitus. Cytoprotection is among the pleiotropic actions described for GLP-1 in different cell types, including cardiomyocytes. This paper reviews the most relevant experimental and clinical studies that have contributed to a better understanding of the molecular mechanisms and intracellular pathways involved in the cardioprotection induced by GLP-1, analysing in depth its potential role as a therapeutic target in the ischaemic and reperfused myocardium as well as in other pathologies that are associated with myocardial remodelling and heart failure.

Cardiotrophin-1 in hypertensive heart disease.

Hypertensive heart disease, here defined by the presence of pathologic left ventricular hypertrophy in the absence of a cause other than arterial hypertension, is characterized by complex changes in myocardial structure including enhanced cardiomyocyte growth and non-cardiomyocyte alterations that induce the remodeling of the myocardium, and ultimately, deteriorate left ventricular function and facilitate the development of heart failure. It is now accepted that a number of pathological processes mediated by mechanical, neurohormonal, and cytokine routes acting on the cardiomyocyte and the non-cardiomyocyte compartments are responsible for myocardial remodeling in the context of arterial hypertension. For instance, cardiotrophin-1 is a cytokine member of the interleukin-6 superfamily, produced by cardiomyocytes and non-cardiomyocytes in situations of biomechanical stress that once secreted interacts with its receptor, the heterodimer formed by gp130 and gp90 (also known as leukemia inhibitory factor receptor beta), activating different signaling pathways leading to cardiomyocyte hypertrophy, as well as myocardial fibrosis. Beyond its potential mechanistic contribution to the development of hypertensive heart disease, cardiotrophin-1 offers the opportunity for a new translational approach to this condition. In fact, recent evidence suggests that cardiotrophin-1 may serve as both a biomarker of left ventricular hypertrophy and dysfunction in hypertensive patients, and a potential target for therapies aimed to prevent and treat hypertensive heart disease beyond blood pressure control.

Antiapoptotic effects of GLP-1 in murine HL-1 cardiomyocytes.

Activation of apoptosis contributes to cardiomyocyte dysfunction and death in diabetic cardiomyopathy. The peptide glucagon-like peptide-1 (GLP-1), a hormone that is the basis of emerging therapy for type 2 diabetic patients, has cytoprotective actions in different cellular models. We investigated whether GLP-1 inhibits apoptosis in HL-1 cardiomyocytes stimulated with staurosporine, palmitate, and ceramide. Studies were performed in HL-1 cardiomyocytes. Apoptosis was induced by incubating HL-1 cells with staurosporine (175 nM), palmitate (135 µM), or ceramide (15 µM) for 24 h. In staurosporine-stimulated HL-1 cardiomyocytes, phosphatidylserine exposure, Bax-to-Bcl-2 ratio, Bad phosphorylation (Ser(136)), BNIP3 expression, mitochondrial membrane depolarization, cytochrome c release, caspase-3 activation, DNA fragmentation, and mammalian target of rapamycin (mTOR)/p70S6K phosphorylation (Ser(2448) and Thr(389), respectively) were assessed. Apoptotic hallmarks were also measured in the absence or presence of low (5 mM) and high (10 mM) concentrations of glucose. In addition, phosphatidylserine exposure and DNA fragmentation were analyzed in palmitate- and ceramide-stimulated cells. Staurosporine increased apoptosis in HL-1 cardiomyocytes. GLP-1 (100 nM) partially inhibited staurosporine-induced mitochondrial membrane depolarization and completely blocked the rest of the staurosporine-induced apoptotic changes. This cytoprotective effect was mainly mediated by phosphatidylinositol 3-kinase (PI3K) and partially dependent on ERK1/2. Increasing concentrations of glucose did not influence GLP-1-induced protection against staurosporine. Furthermore, GLP-1 inhibited palmitate- and ceramide-induced phosphatidylserine exposure and DNA fragmentation. Incretin GLP-1 protects HL-1 cardiomyocytes against activation of apoptosis. This cytoprotective ability is mediated mainly by the PI3K pathway and partially by the ERK1/2 pathway and seems to be glucose independent. It is proposed that therapies based on GLP-1 may contribute to prevent cardiomyocyte apoptosis.

Cardiac resynchronization therapy-induced left ventricular reverse remodelling is associated with reduced plasma annexin A5.

AIMS: Cardiac resynchronization therapy (CRT) diminishes cardiac apoptosis and improves systolic function in heart failure (HF) patients with ventricular dyssynchrony. Plasma annexin A5 (AnxA5), a protein related to cellular damage, is associated with systolic dysfunction. We investigated whether the response to CRT is associated with plasma AnxA5. We also studied AnxA5 overexpression effects in HL-1 cardiomyocytes. METHODS AND RESULTS: AnxA5 ELISA was performed in plasma from 57 patients with HF and ventricular dyssynchrony at baseline and after 1 year of CRT. Patients were categorized as responders if they presented both a reduction in left ventricular (LV) end-systolic volume index (LVESVi) >10% and an increase in LV ejection fraction (LVEF) >10%. HL-1 cells were transfected with human AnxA5 cDNA, and AnxA5, PKC, Akt, p38MAPK, Bcl-2, mitochondrial integrity, caspase-3, and ATP were assessed. At baseline, an increased plasma AnxA5 level was associated with decreased LVEF and increased LVEDVi values (P < 0.05). No differences in baseline AnxA5 were observed between responders and non-responders. After CRT, AnxA5 decreased (P = 0.001) in responders but remained unchanged in non-responders. Final values of AnxA5 were independently associated with LVEF (r = -0.387, P = 0.003) and LVESVi (r = 0.403, P = 0.004) in all patients. Compared with control cells, AnxA5-transfected cells exhibited AnxA5 overexpression, decreased PKC and Akt and increased p38MAPK and Bcl-2 phosphorylation, loss of mitochondrial integrity, caspase-3 activation, and decreased ATP. CONCLUSION: CRT-induced LV reverse remodelling is associated with reduction in plasma AnxA5. The excess of AnxA5 is detrimental for HL-1 cardiomyocytes. Collectively, these data suggest that the beneficial effects of CRT might be related to an AnxA5 decrease.

Cardiovascular translational medicine (III). Genomics and proteomics in heart failure research.

Heart failure is a complex syndrome and is one of the main causes of morbidity and mortality in developed countries. Despite considerable research effort in recent years, heart failure prevention and treatment strategies still suffer significant limitations. New theoretical and technical approaches are, therefore, required. It is in this context that the "omic" sciences have a role to play in heart failure. The incorporation of "omic" methodologies into the study of human disease has substantially changed biological approaches to disease and has given an enormous impetus to the search for new disease mechanisms, as well as for novel biomarkers and therapeutic targets. The application of genomics, proteomics and metabonomics to heart failure research could increase our understanding of the origin and development of the different processes contributing to this syndrome, thereby enabling the establishment of specific diagnostic profiles and therapeutic templates that could help improve the poor prognosis associated with heart failure. This brief review contains a short description of the fundamental principles of the "omic" sciences and an evaluation of how these new techniques are currently contributing to research into human heart failure. The focus is mainly on the analysis of gene expression microarrays in the field of genomics and on studies using two-dimensional electrophoresis with mass spectrometry in the area of proteomics.

La genómica y la proteómica en la investigación de lainsuficiencia cardiaca / Genomics and Proteomics in Heart Failure Research

La insuficiencia cardiaca es un síndrome complejo yuna de las principales causas de morbilidad y mortalidaden los países occidentales. A pesar del enorme esfuerzorealizado en los últimos años, todavía existen importanteslimitaciones en la prevención y el tratamiento de la insuficienciacardiaca, por lo que se impone un nuevo enfoqueconceptual y práctico. En este contexto se inscribela aplicación de las ciencias ®ómicas» a la insuficienciacardiaca. La incorporación de la metodología ®ómica»al estudio de las enfermedades humanas ha modificadosustancialmente el enfoque biológico y ha estimuladoenormemente la investigación de nuevos mecanismos,así como de biomarcadores y dianas terapeúticas. Laaplicación de la genómica, la proteómica y la metabonómicaal estudio de la insuficiencia cardiaca puede facilitarla comprensión del origen y el desarrollo de las distintasentidades que configuran dicho síndrome, con lo que sepropiciaría el establecimiento de perfiles diagnósticos ypatrones terapéuticos diferenciales que pueden mejorarel mal pronóstico que la insuficiencia cardiaca conlleva.En esta breve revisión se definen brevemente aspectosbásicos sobre las ciencias ®ómicas» y se evalúa el estadoactual de la aplicación de estas nuevas tecnologías ala investigación de la insuficiencia cardiaca humana, centrándoseprincipalmente en los análisis de microarrays deexpresión génica en el campo de la genómica y los estudiosde electroforesis bidimensional acoplada a espectrometríade masas en el ámbito de la proteómica (AU)

Heart failure is a complex syndrome and is one of themain causes of morbidity and mortality in developedcountries. Despite considerable research effort in recentyears, heart failure prevention and treatment strategies stillsuffer significant limitations. New theoretical and technicalapproaches are, therefore, required. It is in this contextthat the ®omic» sciences have a role to play in heart failure.The incorporation of ®omic» methodologies into the studyof human disease has substantially changed biologicalapproaches to disease and has given an enormous impetusto the search for new disease mechanisms, as well as fornovel biomarkers and therapeutic targets. The applicationof genomics, proteomics and metabonomics to heart failureresearch could increase our understanding of the originand development of the different processes contributingto this syndrome, thereby enabling the establishment ofspecific diagnostic profiles and therapeutic templates thatcould help improve the poor prognosis associated withheart failure. This brief review contains a short descriptionof the fundamental principles of the ®omic» sciences andan evaluation of how these new techniques are currentlycontributing to research into human heart failure. The focusis mainly on the analysis of gene expression microarrays inthe field of genomics and on studies using two-dimensionalelectrophoresis with mass spectrometry in the area ofproteomics (AU)

Biochemical markers of myocardial remodelling in hypertensive heart disease.

The intricate mechanisms responsible for the structural remodelling of the myocardium that facilitates the evolution to heart failure in hypertensive patients, namely in those with left ventricular hypertrophy, requires from clinicians the utilization of a multibiomarker approach for short-term and long-term stratification as well as prognostication of patients. Biochemical markers may also help to identify patients with no clinical evidence of hypertensive heart disease, and provide information about the need for more aggressive therapy during different stages of the disease, and potentially provide valuable biochemical data for the specialist. Although there is a continuous and complex interplay between biochemical and imaging markers, perhaps their use will also have the potential to modify the medical management of patients with hypertensive heart disease and therapeutic decision-making by tailoring a targeted therapy according to the predominant mechanism of myocardial remodelling. This article will review in brief the most relevant information on a panel of circulating molecules that may accomplish the criteria required to be considered as biochemical markers of the cardiomyocyte and non-cardiomyocyte structural changes that occur in the hypertensive myocardium.