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1.
Cureus ; 16(4): e57741, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38715991

RESUMO

Infective endocarditis (IE) often presents with various signs and/or symptoms. However, at times, IE can present without outstanding clinical evidence but may carry devastating consequences if not detected and treated. We present a case of an 81-year-old female with paroxysmal atrial fibrillation who presented to the emergency department with slurred speech. Her National Institutes of Health Stroke Scale (NIHSS) score was one, and her physical examination was unremarkable. Brain imaging revealed bilateral multiple acute supratentorial and infratentorial infarcts. The patient was fully compliant on apixaban and had a dual-chamber pacemaker placed years earlier at an outside facility for unclear reasons. Although initially suspected to have experienced anticoagulation failure (ACF), transesophageal echocardiography (TEE) was ordered to evaluate for possible left atrial appendage closure procedure, which disclosed a mobile, echo-bright structure on the mitral valve consistent with IE. Blood cultures returned positive, the patient was treated with IV antibiotics, and apixaban was resumed. It can be challenging to suspect IE clinically, especially in deceptive or insidious cases with no signs/symptoms. Still, ACF is a diagnosis of exclusion, and all sources of embolic stroke (such as IE) must be thoroughly worked up before assuming treatment failure.

2.
J Cardiovasc Electrophysiol ; 21(3): 320-4, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19732230

RESUMO

INTRODUCTION: Endpoints confirming block in the critical isthmus in sinus rhythm and with pace mapping have not been established. METHODS AND RESULTS: A 44-year-old man with a history of Tetralogy of Fallot presented with recurrent ventricular tachycardia (VT). Entrainment mapping was consistent with a macroreentrant circuit rotating in a clockwise fashion under the pulmonic valve. After termination of the VT in a critical isthmus located on the conal free wall, a pace map proximal to the site of successful ablation was consistent with a change in QRS morphology. This change in QRS morphology suggested critical isthmus block and successful ablation, which was confirmed by noninducibility with programmed stimulation. CONCLUSION: Evidence of conduction block can be used as an additional endpoint for successful ablation of VT.


Assuntos
Mapeamento Potencial de Superfície Corporal/métodos , Estimulação Cardíaca Artificial/métodos , Determinação de Ponto Final/métodos , Taquicardia Ventricular/diagnóstico , Adulto , Bloqueio Cardíaco/diagnóstico , Humanos , Masculino
3.
Proc Natl Acad Sci U S A ; 106(3): 814-9, 2009 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-19129488

RESUMO

Recent studies support the existence of a common progenitor for the cardiac and endothelial cell lineages, but the underlying transcriptional networks responsible for specification of these cell fates remain unclear. Here we demonstrated that Ets-related protein 71 (Etsrp71), a newly discovered ETS family transcription factor, was a novel downstream target of the homeodomain protein, Nkx2-5. Using genetic mouse models and molecular biological techniques, we demonstrated that Nkx2-5 binds to an evolutionarily conserved Nkx2-5 response element in the Etsrp71 promoter and induces the Etsrp71 gene expression in vitro and in vivo. Etsrp71 was transiently expressed in the endocardium/endothelium of the developing embryo (E7.75-E9.5) and was extinguished during the latter stages of development. Using a gene disruption strategy, we found that Etsrp71 mutant embryos lacked endocardial/endothelial lineages and were nonviable. Moreover, using transgenic technologies and transcriptional and chromatin immunoprecipitation (ChIP) assays, we further established that Tie2 is a direct downstream target of Etsrp71. Collectively, our results uncover a novel functional role for Nkx2-5 and define a transcriptional network that specifies an endocardial/endothelial fate in the developing heart and embryo.


Assuntos
Linhagem da Célula , Endocárdio/embriologia , Endotélio Vascular/embriologia , Proteínas de Homeodomínio/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Ativação Transcricional , Animais , Endocárdio/metabolismo , Endotélio Vascular/metabolismo , Proteína Homeobox Nkx-2.5 , Camundongos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Receptor TIE-2/genética
4.
J Cardiovasc Transl Res ; 2(2): 173-81, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20559985

RESUMO

Bone-marrow-derived stem cells have displayed the potential for myocardial regeneration in animal models as well as in clinical trials. Unfractionated bone marrow mononuclear cell (MNC) population is a heterogeneous group of cells known to include a number of stem cell populations. Cells in the side population (SP) fraction have a high capacity for differentiation into multiple lineages. In the current study, we investigated the role of murine and human bone-marrow-derived side population cells in myocardial regeneration. In these studies, we show that mouse bone-marrow-derived SP cells expressed the contractile protein, alpha-actinin, following culture with neonatal cardiomyocytes and after delivery into the myocardium following injury. Moreover, the number of green-fluorescent-protein-positive cells, of bone marrow side population origin, increased progressively within the injured myocardium over 90 days. Transcriptome analysis of these bone marrow cells reveals a pattern of expression consistent with immature cardiomyocytes. Additionally, the differentiation capacity of human granulocyte colony-stimulating factor stimulated peripheral blood stem cells were assessed following injection into injured rat myocardium. Bone marrow mononuclear cell and side population cells were both readily identified within the rat myocardium 1 month following injection. These human cells expressed human-specific cardiac troponin I as determined by immunohistochemistry as well as numerous cardiac transcripts as determined by polymerase chain reaction. Both human bone marrow mononuclear cells and human side population cells augmented cardiac systolic function following a modest drop in function as a result of cryoinjury. The augmentation of cardiac function following injection of side population cells occurred earlier than with bone marrow mononuclear cells despite the fact that the number of side population cells used was one tenth that of bone marrow mononuclear cells (9 x 10(5) cells per heart in the MNC group compared to 9 x 10(4) per heart in the SP group). These results support the hypotheses that rodent and human-bone-marrow derived side population cells are capable of acquiring a cardiac fate and that human bone-marrow-derived side population cells are superior to unfractionated bone marrow mononuclear cells in augmenting left ventricular systolic function following cryoinjury.


Assuntos
Transplante de Medula Óssea , Cardiopatias/cirurgia , Miocárdio/patologia , Miócitos Cardíacos/transplante , Transplante de Células-Tronco de Sangue Periférico , Regeneração , Transplante de Células-Tronco , Actinina/metabolismo , Animais , Animais Recém-Nascidos , Biomarcadores/metabolismo , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Cardiopatias/genética , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Ratos , Ratos Nus , Recuperação de Função Fisiológica , Regeneração/genética , Fatores de Tempo , Troponina I/metabolismo , Função Ventricular Esquerda
5.
Regen Med ; 3(6): 807-16, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18947305

RESUMO

AIM: Although numerous clinical trials have shown promising results with regards to the cardiac regenerative capacity of different types of stem cells, there remains virtually no evidence of the fate of stem cells in these human studies, primarily owing to safety concerns associated with the use of cell-labeling strategies. METHODS: In this study, we utilized two cell types that are used extensively in cardiac regeneration studies, namely bone marrow-derived human mononuclear cells and C2C12 skeletal myoblasts. The US FDA-approved compounds feridex (ferumoxide) and protamine sulfate (as a transfection agent) were used in combination for cellular labeling. We assessed the effect of this cell labeling strategy on cellular viability, proliferation and differentiation both in vitro and in vivo. RESULTS: The ferumoxide-protamine sulfate combination had no effect on cellular viability, proliferation or differentiation. We show that the labeled human mononuclear cells were easily identified within the rat myocardium 1 month following injection into the myocardium. These human cells expressed human-specific cardiac troponin I, whereas the neighboring rat myocardium did not. Furthermore, we demonstrated that this labeling strategy can be used with high accuracy for magnetic separation of the labeled cells based on the intracellular ferumoxide particles. CONCLUSIONS: The ferumoxide-protamine sulfate combination can be used safely and effectively to enhance the detection and isolation of cardiogenic stem cell populations.


Assuntos
Ferro/metabolismo , Óxidos/metabolismo , Coloração e Rotulagem , Células-Tronco/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Linhagem da Célula/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Separação Celular , Sobrevivência Celular/efeitos dos fármacos , Dextranos , Óxido Ferroso-Férrico , Citometria de Fluxo , Humanos , Ferro/farmacologia , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Magnetismo , Nanopartículas de Magnetita , Camundongos , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Óxidos/farmacologia , Protaminas/metabolismo , Ratos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos
6.
Cardiol Clin ; 26(3): 367-80, vi, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18538185

RESUMO

Ventricular tachycardia in the structurally normal heart accounts for approximately 10% of cases. Although the overall prognosis is relatively good, with a benign course in most patients, these arrhythmias can lead to significant symptoms. Our understanding of these arrhythmias has progressed significantly, leading to effective therapies targeting their underlying mechanism. In many cases, catheter ablation is successful and the therapy of choice in patients who have sufficient symptoms. This article reviews outflow tract, idiopathic left ventricular, and automatic ventricular tachycardias.


Assuntos
Ventrículos do Coração/fisiopatologia , Taquicardia Ventricular/fisiopatologia , Ablação por Cateter , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/terapia
7.
Proc Natl Acad Sci U S A ; 105(16): 6063-8, 2008 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-18420817

RESUMO

The clinical success of stem cell therapy for myocardial repair hinges on a better understanding of cardiac fate mechanisms. We have identified small molecules involved in cardiac fate by screening a chemical library for activators of the signature gene Nkx2.5, using a luciferase knockin bacterial artificial chromosome (BAC) in mouse P19CL6 pluripotent stem cells. We describe a family of sulfonyl-hydrazone (Shz) small molecules that can trigger cardiac mRNA and protein expression in a variety of embryonic and adult stem/progenitor cells, including human mobilized peripheral blood mononuclear cells (M-PBMCs). Small-molecule-enhanced M-PBMCs engrafted into the rat heart in proximity to an experimental injury improved cardiac function better than control cells. Recovery of cardiac function correlated with persistence of viable human cells, expressing human-specific cardiac mRNAs and proteins. Shz small molecules are promising starting points for drugs to promote myocardial repair/regeneration by activating cardiac differentiation in M-PBMCs.


Assuntos
Células-Tronco Adultas/efeitos dos fármacos , Células-Tronco Embrionárias/efeitos dos fármacos , Coração/efeitos dos fármacos , Hidrazonas/farmacologia , Miocárdio/citologia , Regeneração/efeitos dos fármacos , Células-Tronco Adultas/metabolismo , Animais , Células Cultivadas , Cromossomos Artificiais Bacterianos/genética , Avaliação Pré-Clínica de Medicamentos , Células-Tronco Embrionárias/metabolismo , Expressão Gênica/efeitos dos fármacos , Genes Reporter , Coração/fisiologia , Proteína Homeobox Nkx-2.5 , Proteínas de Homeodomínio/genética , Humanos , Hidrazonas/química , Hidrazonas/isolamento & purificação , Luciferases de Vaga-Lume/genética , Camundongos , Miocárdio/metabolismo , Proteínas Nucleares/genética , Ratos , Transativadores/genética , Fatores de Transcrição/genética , Tropomiosina/genética
8.
Am J Physiol Heart Circ Physiol ; 294(2): H936-43, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18083902

RESUMO

The heart adapts to changes in nutritional status and energy demands by adjusting its relative metabolism of carbohydrates and fatty acids. Loss of this metabolic flexibility such as occurs in diabetes mellitus is associated with cardiovascular disease and heart failure. To study the long-term consequences of impaired metabolic flexibility, we have generated mice that overexpress pyruvate dehydrogenase kinase (PDK)4 selectively in the heart. Hearts from PDK4 transgenic mice have a marked decrease in glucose oxidation and a corresponding increase in fatty acid catabolism. Although no overt cardiomyopathy was observed in the PDK4 transgenic mice, introduction of the PDK4 transgene into mice expressing a constitutively active form of the phosphatase calcineurin, which causes cardiac hypertrophy, caused cardiomyocyte fibrosis and a striking increase in mortality. These results demonstrate that cardiac-specific overexpression of PDK4 is sufficient to cause a loss of metabolic flexibility that exacerbates cardiomyopathy caused by the calcineurin stress-activated pathway.


Assuntos
Calcineurina/toxicidade , Cardiomiopatias/enzimologia , Miocárdio/enzimologia , Miocárdio/metabolismo , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Serina-Treonina Quinases/genética , Envelhecimento/fisiologia , Animais , Western Blotting , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/diagnóstico por imagem , Humanos , Ácido Láctico/metabolismo , Camundongos , Camundongos Transgênicos , Piruvato Desidrogenase Quinase de Transferência de Acetil , Ácido Pirúvico/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sobrevida , Ultrassonografia
9.
J Clin Invest ; 117(9): 2486-95, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17786241

RESUMO

Maintenance of skeletal and cardiac muscle structure and function requires precise control of the synthesis, assembly, and turnover of contractile proteins of the sarcomere. Abnormalities in accumulation of sarcomere proteins are responsible for a variety of myopathies. However, the mechanisms that mediate turnover of these long-lived proteins remain poorly defined. We show that muscle RING finger 1 (MuRF1) and MuRF3 act as E3 ubiquitin ligases that cooperate with the E2 ubiquitin-conjugating enzymes UbcH5a, -b, and -c to mediate the degradation of beta/slow myosin heavy chain (beta/slow MHC) and MHCIIa via the ubiquitin proteasome system (UPS) in vivo and in vitro. Accordingly, mice deficient for MuRF1 and MuRF3 develop a skeletal muscle myopathy and hypertrophic cardiomyopathy characterized by subsarcolemmal MHC accumulation, myofiber fragmentation, and diminished muscle performance. These findings identify MuRF1 and MuRF3 as key E3 ubiquitin ligases for the UPS-dependent turnover of sarcomeric proteins and reveal a potential basis for myosin storage myopathies.


Assuntos
Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/metabolismo , Doenças Musculares/enzimologia , Doenças Musculares/patologia , Miosinas/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Proteínas Cromossômicas não Histona , Proteínas de Ligação a DNA/genética , Cardiopatias/enzimologia , Cardiopatias/genética , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Microscopia Eletrônica , Doenças Musculares/genética , Complexo Repressor Polycomb 1 , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição , Ubiquitina/metabolismo
10.
Proc Natl Acad Sci U S A ; 104(11): 4377-82, 2007 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-17360532

RESUMO

RING-finger proteins commonly function as ubiquitin ligases that mediate protein degradation by the ubiquitin-proteasome pathway. Muscle-specific RING-finger (MuRF) proteins are striated muscle-restricted components of the sarcomere that are thought to possess ubiquitin ligase activity. We show that mice lacking MuRF3 display normal cardiac function but are prone to cardiac rupture after acute myocardial infarction. Cardiac rupture is preceded by left ventricular dilation and a severe decrease in cardiac contractility accompanied by myocyte degeneration. Yeast two-hybrid assays revealed four-and-a-half LIM domain (FHL2) and gamma-filamin proteins as MuRF3 interaction partners, and biochemical analyses showed these proteins to be targets for degradation by MuRF3. Accordingly, FHL2 and gamma-filamin accumulated to abnormal levels in the hearts of mice lacking MuRF3. These findings reveal an important role of MuRF3 in maintaining cardiac integrity and function after acute myocardial infarction and suggest that turnover of FHL2 and gamma-filamin contributes to this cardioprotective function of MuRF3.


Assuntos
Proteínas Musculares/fisiologia , Infarto do Miocárdio/patologia , Animais , Proteínas Contráteis/metabolismo , Ecocardiografia , Filaminas , Proteínas de Homeodomínio/metabolismo , Proteínas com Homeodomínio LIM , Masculino , Camundongos , Camundongos Knockout , Proteínas dos Microfilamentos/metabolismo , Modelos Genéticos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Miocárdio/metabolismo , Estrutura Terciária de Proteína , Sarcômeros/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Regulação para Cima
11.
Trends Cardiovasc Med ; 16(7): 234-40, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16980180

RESUMO

Elegant studies using gene disruption strategies have defined a set of genes that are essential for normal cardiac development. Although these studies have provided a framework for the molecular regulation of cardiac morphogenesis, the genetic program of the cardiac progenitors has been incompletely defined. We used a transgenic strategy to specifically target the cardiac progenitors early during cardiac morphogenesis. With the use of flow cytometry and transcriptome analysis, we comprehensively defined the molecular program of the cardiac progenitors at distinct developmental stages. Definition of the molecular cardiac program early during development may be useful in the identification of cardiac progenitors that are resident in the adult heart. These emerging technologies will be further used to define common and distinct regulatory pathways of cardiac progenitors in the developing and regenerating heart.


Assuntos
Coração/fisiologia , Regeneração , Transdução de Sinais , Transcrição Gênica , Animais , Diferenciação Celular , Regulação da Expressão Gênica no Desenvolvimento , Coração/crescimento & desenvolvimento , Cardiopatias Congênitas/complicações , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/fisiopatologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/fisiopatologia , Humanos , Miócitos Cardíacos/fisiologia , Células-Tronco/fisiologia
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