RESUMEN

UNLABELLED: Cardiac c-Kit+ cells have a modest cardiogenic potential that could limit their efficacy in heart disease treatment. The present study was designed to augment the cardiogenic potential of cardiac c-Kit+ cells through class I histone deacetylase (HDAC) inhibition and evaluate their therapeutic potency in the chronic heart failure (CHF) animal model. Myocardial infarction (MI) was created by coronary artery occlusion in rats. c-Kit+ cells were treated with mocetinostat (MOCE), a specific class I HDAC inhibitor. At 3 weeks after MI, CHF animals were retrogradely infused with untreated (control) or MOCE-treated c-Kit+ cells (MOCE/c-Kit+ cells) and evaluated at 3 weeks after cell infusion. We found that class I HDAC inhibition in c-Kit+ cells elevated the level of acetylated histone H3 (AcH3) and increased AcH3 levels in the promoter regions of pluripotent and cardiac-specific genes. Epigenetic changes were accompanied by increased expression of cardiac-specific markers. Transplantation of CHF rats with either control or MOCE/c-Kit+ cells resulted in an improvement in cardiac function, retardation of CHF remodeling made evident by increased vascularization and scar size, and cardiomyocyte hypertrophy reduction. Compared with CHF infused with control cells, infusion of MOCE/c-Kit+ cells resulted in a further reduction in left ventricle end-diastolic pressure and total collagen and an increase in interleukin-6 expression. The low engraftment of infused cells suggests that paracrine effects might account for the beneficial effects of c-Kit+ cells in CHF. In conclusion, selective inhibition of class I HDACs induced expression of cardiac markers in c-Kit+ cells and partially augmented the efficacy of these cells for CHF repair. SIGNIFICANCE: The study has shown that selective class 1 histone deacetylase inhibition is sufficient to redirect c-Kit+ cells toward a cardiac fate. Epigenetically modified c-Kit+ cells improved contractile function and retarded remodeling of the congestive heart failure heart. This study provides new insights into the efficacy of cardiac c-Kit+ cells in the ischemic heart failure model.

Asunto(s)

Epigénesis Genética , Insuficiencia Cardíaca/terapia , Infarto del Miocardio/terapia , Miocitos Cardíacos/trasplante , Proteínas Proto-Oncogénicas c-kit/genética , Acetilación , Animales , Benzamidas/farmacología , Biomarcadores/metabolismo , Diferenciación Celular , Células Cultivadas , Colágeno/genética , Colágeno/metabolismo , Modelos Animales de Enfermedad , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/fisiopatología , Inhibidores de Histona Desacetilasas/farmacología , Histonas/genética , Histonas/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Infarto del Miocardio/genética , Infarto del Miocardio/metabolismo , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/metabolismo , Proteínas Proto-Oncogénicas c-kit/metabolismo , Pirimidinas/farmacología , Ratas , Ratas Sprague-Dawley , Recuperación de la Función , Técnicas de Cultivo de Tejidos , Función Ventricular Izquierda , Remodelación Ventricular

RESUMEN

OBJECTIVES: Nitric oxide (NO) is a critical regulator of vascular tone and signal transduction in the cardiovascular system. NO is synthesized by three unique enzymes (nitric oxide synthases [NOS]): endothelial and neuronal NOS, both constitutively expressed, and inducible NOS (iNOS), which is induced by proinflammatory stimuli and subsequently produces a burst of NO. NO has been implicated as both an injurious and a beneficial mediator after cardiac arrest and resuscitation. A previous study in swine found that iNOS expression is absent in the myocardium prior to cardiac arrest and that it increases after 10 minutes of untreated ventricular fibrillation (VF), decreases somewhat during the early postresuscitation period, and then steadily increases up to 6 hours postresuscitation. Because this time course of iNOS expression mirrors that of postresuscitation myocardial dysfunction, this study was designed to test the hypothesis that selective inhibition of iNOS improves postresuscitation outcomes in swine. METHODS: Thirty-two domestic swine of either sex were randomly assigned to receive one of the following treatments 15 minutes after return of spontaneous circulation (ROSC): (1) N(G) -nitro-l-arginine methyl ester (l-NAME), a global NO inhibitor; (2) aminoguanidine (AG), a selective iNOS inhibitor; or (3) saline as control. After 10 minutes of untreated VF, swine received a standard resuscitation protocol. Twenty-four-hour survival, neurological status, left ventricular (LV) function, and hemodynamic measurements were obtained. RESULTS: Return of spontaneous circulation occurred in 28 of 32 animals (88%). Only successfully resuscitated animals were assigned to treatment groups and completed the study. There were no differences in survival or neurological outcomes between groups. There were also no differences in LV function or hemodynamic variables found between the control group and the AG group. Global inhibition of NOS with l-NAME post-ROSC increased aortic pressure and transiently decreased pulse pressure. Treatment with l-NAME also increased LV end diastolic pressure and decreased cardiac output within 30 minutes post-ROSC, which was sustained throughout the 4-hour measurements, compared to both the control and the AG groups. In addition, LV ejection fraction recovered to baseline measurements in both the control and AG groups, but failed to recover in the l-NAME group. CONCLUSIONS: Global inhibition of NOS after cardiac arrest and resuscitation markedly worsens hemodynamic variables. Selective inhibition of iNOS after cardiac arrest and resuscitation does not prevent postresuscitation myocardial stunning. There were no significant differences in neurological outcome or survival between treatment groups.

Asunto(s)

Paro Cardíaco/fisiopatología , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Óxido Nítrico Sintasa/antagonistas & inhibidores , Resucitación , Función Ventricular Izquierda/efectos de los fármacos , Animales , Inhibidores Enzimáticos/farmacología , Femenino , Guanidinas/farmacología , Paro Cardíaco/terapia , Hemodinámica/fisiología , Masculino , NG-Nitroarginina Metil Éster/farmacocinética , Distribución Aleatoria , Porcinos , Función Ventricular Izquierda/fisiología

RESUMEN

BACKGROUND: Interstitial fibrosis and fibrotic scar formation contribute to cardiac remodeling and loss of cardiac function in myocardial infarction (MI) and heart failure. Recent studies showed that histone deacetylase (HDAC) inhibitors retard fibrosis formation in acute MI settings. However, it is unknown whether HDAC inhibition can reverse cardiac fibrosis in ischemic heart failure. In addition, specific HDAC isoforms involved in cardiac fibrosis and myofibroblast activation are not well defined. Thus, the purpose of this study is to determine the effects of selective class I HDAC inhibition on cardiac fibroblasts activation and cardiac fibrosis in a congestive heart failure (CHF) model secondary to MI. METHODS: MI was created by left anterior descending (LAD) coronary artery occlusion. Class I HDACs were selectively inhibited via Mocetinostat in CD90+ fibroblasts isolated from atrial and ventricular heart tissue in vitro. In vivo, Class I HDACs were inhibited in 3 weeks post MI rats by injecting Mocetinostat for the duration of 3 weeks. Cardiac function and heart tissue were analyzed at 6 weeks post MI. RESULTS: In sham hearts, HDAC1 and HDAC2 displayed differential expression patterns where HDAC1 mainly expressed in cardiac fibroblast and HDAC2 in cardiomyocytes. On the other hand, we showed that HDAC1 and 2 were upregulated in CHF hearts, and were found to co-localize with CD90+ cardiac fibroblasts. In vivo treatment of CHF animals with Mocetinostat improved left ventricle end diastolic pressure and dp/dt max and decreased the total collagen amount. In vitro treatment of CD90+ cells with Mocetinostat reversed myofibroblast phenotype as indicated by a decrease in α-Smooth muscle actin (α-SMA), Collagen III, and Matrix metalloproteinase-2 (MMP2). Furthermore, Mocetinostat increased E-cadherin, induced ß-catenin localization to the membrane, and reduced Akt/GSK3ß signaling in atrial cardiac fibroblasts. In addition, Mocetinostat treatment of atrial CD90+ cells upregulated cleaved-Caspase3 and activated the p53/p21 axis. CONCLUSIONS: Taken together, our results demonstrate upregulation of HDAC1 and 2 in CHF. In addition, HDAC inhibition reverses interstitial fibrosis in CHF. Possible anti-fibrotic actions of HDAC inhibition include reversal of myofibroblast activation and induction of cell cycle arrest/apoptosis.

RESUMEN

BACKGROUND: Progenitor cells isolated from cardiac explant-derived cells improve cardiac function after myocardial infarction (MI). To fully realize the therapeutic potential of these cells, it is essential to develop a safe and efficient delivery method. Therefore, the objective of this study was to determine the efficacy of our newly developed approach to retrograde coronary vein (RCV) infusion of cardiac c-Kit(+) cells in a small-animal model of congestive heart failure (CHF). METHODS: Sprague-Dawley rats underwent experimental MI. After 21 days, cardiac explant-derived c-Kit(+) cells were delivered to both sham and CHF animals using RCV delivery. Vehicle-treated (serum-free medium) sham and CHF animals were used as controls. Cardiac function and heart tissues were evaluated 21 days post-transplantation. RESULTS: RCV-delivered cells were retained in infarcted hearts for at least 21 days after transplantation. At 21 days post-RCV infusion, the majority of transplanted c-Kit(+)/GFP(+) cells were localized in the left ventricle. Compared with vehicle-treated CHF animals, RCV-treated rats showed a significant improvement in cardiac function. Furthermore, RCV-treated rats exhibited an increase in capillary density, a decrease in total heart collagen, and a reduction in both infarct size and cardiomyocyte hypertrophy when compared with vehicle-treated CHF rats. CONCLUSIONS: Our study showed that the RCV infusion approach is an efficient technique for targeted cell delivery to the infarcted myocardium. Cardiac c-Kit(+) cells, delivered using RCV infusion ameliorated progression of heart failure, improved cardiac function and retarded myocardial remodeling in heart failure rats.

Asunto(s)

Insuficiencia Cardíaca/terapia , Infarto del Miocardio/complicaciones , Miocitos Cardíacos/trasplante , Proteínas Proto-Oncogénicas c-kit , Trasplante de Células Madre/métodos , Animales , Vasos Coronarios , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/patología , Infusiones Intravenosas , Masculino , Infarto del Miocardio/patología , Infarto del Miocardio/terapia , Ratas Sprague-Dawley , Remodelación Ventricular

RESUMEN

BACKGROUND: Varying strategies are currently being evaluated to develop tissue-engineered constructs for the treatment of ischemic heart disease. This study examines an angiogenic and biodegradable cardiac construct seeded with neonatal cardiomyocytes for the treatment of chronic heart failure (CHF). METHODS: We evaluated a neonatal cardiomyocyte (NCM)-seeded 3-dimensional fibroblast construct (3DFC) in vitro for the presence of functional gap junctions and the potential of the NCM-3DFC to restore left ventricular (LV) function in an in vivo rat model of CHF at 3 weeks after permanent left coronary artery ligation. RESULTS: The NCM-3DFC demonstrated extensive cell-to-cell connectivity after dye injection. At 5 days in culture, the patch contracted spontaneously in a rhythmic and directional fashion at 43 ± 3 beats/min, with a mean displacement of 1.3 ± 0.3 mm and contraction velocity of 0.8 ± 0.2 mm/sec. The seeded patch could be electrically paced at nearly physiologic rates (270 ± 30 beats/min) while maintaining coordinated, directional contractions. Three weeks after implantation, the NCM-3DFC improved LV function by increasing (p < 0.05) ejection fraction 26%, cardiac index 33%, dP/dt(+) 25%, dP/dt(-) 23%, and peak developed pressure 30%, while decreasing (p < 0.05) LV end diastolic pressure 38% and the time constant of relaxation (Tau) 16%. At 18 weeks after implantation, the NCM-3DFC improved LV function by increasing (p < 0.05) ejection fraction 54%, mean arterial pressure 20%, dP/dt(+) 16%, dP/dt(-) 34%, and peak developed pressure 39%. CONCLUSIONS: This study demonstrates that a multicellular, electromechanically organized cardiomyocyte scaffold, constructed in vitro by seeding NCM onto 3DFC, can improve LV function long-term when implanted in rats with CHF.

Asunto(s)

Estimulación Cardíaca Artificial , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Isquemia Miocárdica/fisiopatología , Isquemia Miocárdica/terapia , Miocitos Cardíacos/trasplante , Neovascularización Fisiológica/fisiología , Ingeniería de Tejidos/métodos , Andamios del Tejido , Función Ventricular Izquierda/fisiología , Animales , Comunicación Celular/fisiología , Diferenciación Celular/fisiología , Modelos Animales de Enfermedad , Ecocardiografía , Insuficiencia Cardíaca/patología , Hemodinámica/fisiología , Isquemia Miocárdica/patología , Miocitos Cardíacos/patología , Ratas , Ratas Sprague-Dawley , Volumen Sistólico/fisiología

RESUMEN

BACKGROUND: Cardiac c-Kit+ cells isolated from cardiac explant-derived cells modestly improve cardiac functions after myocardial infarction; however, their full potential has not yet been realized. For instance, the majority of potential candidates for cell therapy suffer from chronic heart failure (CHF), and it is unclear how this disease affects the explant-derived progenitor cells. Therefore, the objective of this study was to determine the effect of CHF on the number and phenotype of cardiac explant c-Kit+ progenitors and elucidate mechanisms of their regulation. METHODS AND RESULTS: Myocardial infarction was created by left anterior descending coronary artery occlusion. Sham-operated animals were used as a control group. CHF-developed infarcted animals were selected on the basis of left ventricle end-diastolic pressure ≥ 20 mm Hg and scar size ≥ 30%. Here, we found that CHF atrial explants produced less c-Kit+ cells than sham explants. CHF-derived c-Kit+ cells exhibited upregulated transforming growth factor-ß (TGF-ß) signaling, increased level of epithelial to mesenchymal transition markers, and diminished expression of pluripotency markers compared with shams. We show that intervention with TGF-ß signaling by inhibiting TGF-ß receptor type I or Smad 2/3 using small-molecule inhibitors improved c-Kit+ cell yield, attenuated epithelial to mesenchymal transition markers, stimulated the pluripotency marker Nanog, and improved efficiency of c-Kit+ cell differentiation toward cardiomyocyte-like cells in vitro. CONCLUSIONS: Taken together, our findings suggest that TGF-ß inhibition positively modulates c-Kit+ cell phenotype and function in vitro, and this strategy may be considered in optimizing cardiac progenitor function and cell expansion protocols for clinical application.

Asunto(s)

Atrios Cardíacos/citología , Insuficiencia Cardíaca/patología , Factor de Crecimiento Transformador beta/fisiología , Animales , Células Cultivadas , Enfermedad Crónica , Ratas , Ratas Sprague-Dawley

RESUMEN

Cardiovascular (CV) diseases are known to have a negative impact on the brain and neurocognition, and contribute to the development of vascular dementia and neurodegenerative diseases such as Alzheimer's disease (AD). Among CV diseases, congestive heart failure (CHF) after myocardial infarction (MI) is a condition where the ability of the left ventricle to eject blood to the circulation is impaired. As a consequence, CHF triggers inflammation and results in reduced cerebral blood flow which are considered among the risk factors for development of AD. However, biochemical alterations in the brain following MI and CHF remain unknown. To address this issue, we investigated microglia activation; levels of BACE1, the key rate-limiting enzyme involved in the pathogenesis of AD; and VEGF levels in the hippocampus and cortex following MI. We created MI by the ligation of the left anterior descending coronary artery in Sprague-Dawley male rats and collected brains either 3 days after MI (AMI) or 21 days after MI (CHF). We investigated microglia activation in AMI and CHF brains by immunohistochemistry and immunoblotting using macrophage/microglia marker Ionized calcium binding adaptor molecule 1 (Iba-1), and observed activated morphology of microglia in the cortex of rats in both AMI and CHF. We also showed the levels of BACE1 were increased in the cortex and hippocampus of CHF rats. To determine whether hypoxia occurs in the CHF brain, we assessed levels of VEGF in the hippocampus and cortex. Western blotting analysis showed up-regulation of VEGF in the hippocampus of CHF brains. These results suggest that neuroinflammation takes place secondary to myocardial infarction. In addition, CHF-induced hypoxia might play a role in the elevation of BACE1 and VEGF levels.

Asunto(s)

Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Insuficiencia Cardíaca/metabolismo , Animales , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Insuficiencia Cardíaca/patología , Insuficiencia Cardíaca/fisiopatología , Hipocampo/metabolismo , Hipocampo/patología , Masculino , Microglía/metabolismo , Infarto del Miocardio/metabolismo , Infarto del Miocardio/fisiopatología , Ratas , Ratas Sprague-Dawley , Factor A de Crecimiento Endotelial Vascular/metabolismo , Función Ventricular Izquierda

RESUMEN

BACKGROUND: Progenitor cell therapy is emerging as a novel treatment for heart failure. However the molecular mechanisms regulating the generation of cardiac progenitor cells is not fully understood. We hypothesized that cardiac progenitor cells are generated from cardiac explant via a process similar to epithelial to mesenchymal transition (EMT). METHODS/FINDINGS: Explant-derived cells were generated from partially digested atrial tissue. After 21 days in culture, c-Kit+ cells were isolated from cell outgrowth. The majority of explant-originated c-Kit+ cells expressed the epicardial marker Wt1. Cardiac cell outgrowth exhibits a temporal up-regulation of EMT-markers. Notch stimulation augmented, while Notch inhibition suppressed, mesenchymal transition in both c-Kit+ and c-Kit- cells. In c-Kit+ cells, Notch stimulation reduced, while Notch inhibition up-regulated pluripotency marker expressions such as Nanog and Sox2. Notch induction was associated with degradation of ß-catenin in c-Kit- cells. In contrast, Notch inhibition resulted in ß-catenin accumulation, acquisition of epitheloid morphology, and up-regulation of Wnt target genes in c-Kit- cells. CONCLUSION: Our study suggests that Notch-mediated reversible EMT process is a mechanism that regulates explant-derived c-Kit+ and c-Kit- cells.

Asunto(s)

Transición Epitelial-Mesenquimal , Miocardio/citología , Receptores Notch/metabolismo , Células Madre/metabolismo , Animales , Proteínas de Unión al Calcio/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Miocardio/metabolismo , Fenotipo , Proteínas Proto-Oncogénicas c-kit/genética , Proteínas Proto-Oncogénicas c-kit/metabolismo , Ratas , Ratas Sprague-Dawley , Receptor Notch1/metabolismo , Proteínas Serrate-Jagged , Transducción de Señal , Proteínas Wnt/metabolismo , beta Catenina/metabolismo

RESUMEN

AIMS: Cell-based therapy for myocardial infarction (MI) holds great promise; however, the ideal cell type and delivery system have not been established. Obstacles in the field are the massive cell death after direct injection and the small percentage of surviving cells differentiating into cardiomyocytes. To overcome these challenges we designed a novel study to deliver cardiac progenitor cells as a cell sheet. METHODS AND RESULTS: Cell sheets composed of rat or human cardiac progenitor cells (cardiospheres), and cardiac stromal cells were transplanted onto the infarcted myocardium after coronary artery ligation in rats. Three weeks later, transplanted cells survived, proliferated, and differentiated into cardiomyocytes (14.6 +/- 4.7%). Cell sheet transplantation suppressed cardiac wall thinning and increased capillary density (194 +/- 20 vs. 97 +/- 24 per mm(2), P < 0.05) compared with the untreated MI. Cell migration from the sheet was observed along the necrotic trails within the infarcted area. The migrated cells were located in the vicinity of stromal-derived factor (SDF-1) released from the injured myocardium, and about 20% of these cells expressed CXCR4, suggesting that the SDF-1/CXCR4 axis plays, at least, a role in cell migration. Transplantation of cell sheets resulted in a preservation of cardiac contractile function after MI, as was shown by a greater ejection fraction and lower left ventricular end diastolic pressure compared with untreated MI. CONCLUSION: The scaffold-free cardiosphere-derived cell sheet approach seeks to efficiently deliver cells and increase cell survival. These transplanted cells effectively rescue myocardium function after infarction by promoting not only neovascularization but also inducing a significant level of cardiomyogenesis.

Asunto(s)

Desarrollo de Músculos , Infarto del Miocardio/cirugía , Miocitos Cardíacos/trasplante , Regeneración , Trasplante de Células Madre , Función Ventricular Izquierda , Animales , Diferenciación Celular , Movimiento Celular , Proliferación Celular , Supervivencia Celular , Células Cultivadas , Quimiocina CXCL12/metabolismo , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Humanos , Masculino , Contracción Miocárdica , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Neovascularización Fisiológica , Ratas , Ratas Sprague-Dawley , Recuperación de la Función , Volumen Sistólico , Células del Estroma/trasplante , Factores de Tiempo , Presión Ventricular , Remodelación Ventricular

RESUMEN

Myocardial infarction (MI) and stroke are the first and third leading causes of death in the U.S.A. accounting for more than 1 in 3 deaths per annum. Despite interventional and pharmaceutical advances, the number of people diagnosed with heart disease is on the rise. Therefore, new clinical strategies are needed. Cell-based therapy holds great promise for treatment of these diseases and is currently under extensive preclinical as well as clinical trials. The source and types of stem cells for these clinical applications are questions of great interest. Human umbilical cord blood (hUCB) appears to be a logical candidate as a source of cells. hUCB is readily available, and presents little ethical challenges. Stem cells derived from hUCB are multipotent and immunologically naive. Here is a critical literature review of the beneficial effects of hUCB cell therapy in preclinical trials.

Asunto(s)

Trasplante de Células Madre de Sangre del Cordón Umbilical/métodos , Infarto del Miocardio/cirugía , Accidente Cerebrovascular/cirugía , Animales , Causas de Muerte/tendencias , Humanos , Infarto del Miocardio/mortalidad , Accidente Cerebrovascular/mortalidad , Resultado del Tratamiento , Estados Unidos/epidemiología

RESUMEN

AIM: Increases in serum cytokines have been reported after successful resuscitation from prolonged ventricular fibrillation (VF). Pro-inflammatory cytokines can stimulate inducible nitric oxide synthase (iNOS) to produce excessive levels of nitric oxide (NO). High levels of both myocardial inflammatory cytokines and nitric oxide levels can depress myocardial contractile function. We hypothesized that myocardial pro-inflammatory cytokines and iNOS activity would increase following successful resuscitation from prolonged ventricular fibrillation cardiac arrest, and that such increases would parallel the development of post-resuscitation myocardial dysfunction. METHODS: Ventricular fibrillation cardiac arrest was induced in seven domestic swine (25+/-5 kg). After 10 min of untreated VF, the animals were defibrillated and resuscitated. Left ventricular (LV) systolic and diastolic function measurements, serum samples (arterial and coronary sinus) for IL-8 cytokine quantification, and LV myocardial biopsies were collected before, during, and after resuscitation. Quantification of myocardial endothelial (eNOS) and inducible (iNOS) nitric oxide synthase protein levels were determined using immunoblot analyses and protein localization was examined using immunohistochemistry. RESULTS: Post-resuscitation LV systolic and diastolic functions were depressed while increases in both coronary sinus IL-8 levels and myocardial iNOS activity were found. Compared to pre-arrest baseline, levels of iNOS protein increased during VF (p < or = 0.05) and continued to increase throughout the post-resuscitation study period of 6 h (p < or = 0.05). CONCLUSIONS: Myocardial inflammatory cytokines and iNOS activity increase during and after prolonged cardiac arrest and successful resuscitation. These increases correspond to the well described decrease in LV function post-resuscitation.

Asunto(s)

Corazón/fisiopatología , Interleucina-8/biosíntesis , Óxido Nítrico Sintasa/biosíntesis , Resucitación , Fibrilación Ventricular/metabolismo , Fibrilación Ventricular/terapia , Animales , Femenino , Interleucina-8/análisis , Masculino , Miocardio/química , Óxido Nítrico Sintasa/análisis , Óxido Nítrico Sintasa/metabolismo , Porcinos

RESUMEN

Angiotensin II receptor blockade (ARB) increases vasorelaxation in heart failure by enhancing endothelial nitric oxide (NO). To determine the effects of valsartan on NO-mediated peripheral vascular function after myocardial infarction (MI), we treated adult male Sprague-Dawley rats immediately after MI with valsartan for 3 weeks (sham, n = 10; MI, n = 11) and 6 weeks (sham, n = 6; MI, n = 8). At both time points, valsartan lowered (P < 0.05) left ventricular (LV) systolic pressure (103 +/- 4 and 107 +/- 4 vs. 93 +/- 3 and 85 +/- 4 mm Hg, respectively) and LV end-diastolic pressure (25 +/- 1 and 25 +/- 2 to 13 +/- 2 and 18 +/- 3 mm Hg, respectively). Valsartan lowered (P < 0.05) LV dP/dt only at 6 weeks (4676 +/- 168 and 4503 +/- 232 vs. 4539 +/- 281 and 3372 +/- 417 mm Hg/sec); valsartan shortened (P < 0.05) the time constant of LV relaxation or tau only at 3 weeks (24.2 +/- 1.8 and 26.5 +/- 2.3 vs. 20.1 +/- 0.7 and 23.8 +/- 1.4 msec). At 6 weeks, the vasorelaxation response to acetycholine in aortic rings was decreased (P < 0.05) with MI and improved at acetycholine doses (10, 10, and 10; P < 0.06) with valsartan. Endothelial nitric oxide synthase (eNOS) protein was undetectable in aortic tissue from valsartan treated rats or from aortic tissue incubated with valsartan (2.5, 25, and 50 mg/mL). These data suggest that valsartan improves cardiac function after MI by modulating LV remodeling, decreasing LV end-diastolic pressure, and enhancing both LV diastolic and endothelial function. These effects are mediated, in part, by NO but upregulation of eNOS may not be required for improved systemic endothelial function in heart failure.

Asunto(s)

Endotelio Vascular/fisiología , Insuficiencia Cardíaca/tratamiento farmacológico , Infarto del Miocardio/fisiopatología , Tetrazoles/farmacología , Valina/análogos & derivados , Vasodilatación/efectos de los fármacos , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/metabolismo , Aorta Torácica/fisiopatología , Presión Sanguínea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Insuficiencia Cardíaca/fisiopatología , Técnicas In Vitro , Masculino , Óxido Nítrico Sintasa de Tipo II/metabolismo , Óxido Nítrico Sintasa de Tipo III , Ratas , Ratas Sprague-Dawley , Tetrazoles/uso terapéutico , Factores de Tiempo , Valina/farmacología , Valina/uso terapéutico , Valsartán , Función Ventricular Izquierda/efectos de los fármacos , Remodelación Ventricular/efectos de los fármacos

RESUMEN

It is estimated that up to 128 million individuals might benefit from regenerative medicine therapy, or almost 1 in 3 individuals in the US. If accurate, the need to relieve suffering and reduce healthcare costs is an enormous motivator to rapidly bring stem cell therapies to the clinic. Unfortunately, embryonic stem (ES) cell therapies are limited at present by ethical and political constraints and, most importantly, by significant biologic hurdles. Thus, for the foreseeable future, the march of regenerative medicine to the clinic will depend on the development of non-ES cell therapies. At present, non-ES cells easily available in large numbers can be found in the bone marrow, adipose tissue and umbilical cord blood (CB). Each of these stem cells is being used to treat a variety of diseases. This review shows that CB contains multiple populations of pluripotent stem cells, and can be considered the best alternative to ES cells. CB stem cells are capable of giving rise to hematopoietic, epithelial, endothelial and neural tissues both in vitro and in vivo. Thus, CB stem cells are amenable to treat a wide variety of diseases including cardiovascular, ophthalmic, orthopedic, neurologic and endocrine diseases.

Asunto(s)

Trasplante de Células Madre de Sangre del Cordón Umbilical , Sangre Fetal/citología , Medicina Regenerativa/tendencias , Animales , Humanos

RESUMEN

The heart does not mend itself after infarction. However, stem cells may revolutionize heart disease treatment. A vast and growing body of evidence indicates that cell-based strategies have promising therapeutic potential. Recent clinical and pre-clinical studies demonstrate varying degrees of improvement in cardiac function using different adult stem cell types such as bone marrow (BM)-derived progenitor cells and skeletal myoblasts. However, the efficacy of cell therapy after myocardial infarction (MI) is inconclusive and the cellular source with the highest potential for regeneration is unclear. Clinically, BM and skeletal muscle are the most commonly used sources of autologous stem cells. One major pitfall of using autologous stem cells is that the number of functional cells is generally depleted in the elderly and chronically ill. Therefore, there is an urgent need for a new source of adult stem cells. Human umbilical cord blood (CB) is a candidate and appears to have several key advantages. CB is a viable and practical source of progenitor cells. The cells are naïve and what's more, CB contains a higher number of immature stem/progenitor cells than BM. We review recent clinical experience with adult stem cells and explore the potential of CB as a source of cells for cardiac repair following MI. We conclude that there is a conspicuous absence of clinical studies utilizing CB-derived cells and there is a pressing need for large randomized double-blinded clinical trials to assess the overall efficacy of cell-based therapy.

Asunto(s)

Células Madre Adultas/trasplante , Infarto del Miocardio/cirugía , Adulto , Células de la Médula Ósea/citología , Ensayos Clínicos como Asunto , Sangre Fetal/citología , Humanos , Metaanálisis como Asunto , Infarto del Miocardio/patología , Trasplante de Células Madre/métodos , Trasplante de Células Madre/tendencias

RESUMEN

BACKGROUND: This study was designed to determine the effects of pretreatment with an angiotensin receptor blocker on left ventricular (LV) function and remodeling during acute myocardial infarction (MI). METHODS AND RESULTS: Sprague-Dawley rats were pretreated with candesartan (10 mg x kg(-1) x d(-1)) for 2 weeks and studied at 1, 3, and 6 minutes after MI. Compared with untreated rats, pretreatment with candesartan lowered (P<0.05) LV systolic pressure and the first derivative of LV pressure with respect to time but did not change LV end-diastolic pressure or improve LV regional function. With candesartan pretreatment, LV fractional shortening and ejection fraction increased (P<0.05) by 37% and 28%, and LV chamber dilation was attenuated (P<0.05). At 6 minutes after MI, LV endothelial nitric oxide synthase decreased in the infarcted and noninfarcted wall 47% (P=0.04) and 70% (P=0.002), and constitutive microtubulin increased 260% (P=0.0005) and 111% (P=0.003). Candesartan had no effect on LV tissue endothelial nitric oxide synthase levels but attenuated the increase in constitutive microtubulin by 77% (P=0.004) and 37% (P<0.05). CONCLUSIONS: Pretreatment with candesartan before an acute MI improves global LV function, prevents LV dilation, and blunts the increase in constitutive microtubulin, with minimal effects on LV hemodynamics, regional function, or tissue endothelial nitric oxide synthase. Thus, candesartan given before an MI attenuates LV remodeling and alters the cytoskeleton matrix of the left ventricle.

Asunto(s)

Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Bencimidazoles/uso terapéutico , Infarto del Miocardio/tratamiento farmacológico , Tetrazoles/uso terapéutico , Disfunción Ventricular Izquierda/prevención & control , Remodelación Ventricular/efectos de los fármacos , Animales , Compuestos de Bifenilo , Masculino , Infarto del Miocardio/metabolismo , Infarto del Miocardio/fisiopatología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Ratas , Ratas Sprague-Dawley , Tubulina (Proteína)/metabolismo , Función Ventricular Izquierda/efectos de los fármacos

RESUMEN

BACKGROUND: This study was designed to determine whether tissue engineering could be used to reduce ventricular remodeling in a rat model of non-transmural, non-ST-elevation myocardial infarction. METHODS: We grafted an acellular 3-dimensional (3D) collagen type 1 scaffold (solid porous foam) onto infarcted myocardium in rats. Three weeks after grafting, the scaffold was integrated into the myocardium and retarded cardiac remodeling by reducing left ventricular (LV) dilation. The LV inner and outer diameters, measured at the equator at zero LV pressure, decreased (p < 0.05) from 11,040 +/- 212 to 9,144 +/- 135 microm, and 13,469 +/- 187 to 11,673 +/- 104 microm (N = 12), after scaffold transplantation onto infarcted myocardium. The scaffold also shifted the LV pressure-volume curve to the left toward control and induced neo-angiogenesis (700 +/- 25 vs 75 +/- 11 neo-vessels/cm2, N = 5, p < 0.05). These vessels (75 +/- 11%) ranged in diameter from 25 to 100 microm and connected to the native coronary vasculature. Systemic treatment with granulocyte-colony stimulating factor (G-CSF), 50 microg/kg/day for 5 days immediately after myocardial injury, increased (p < 0.05) neo-vascular density from 700 +/- 25 to 978 +/- 57 neo-vessels/cm2. CONCLUSIONS: A 3D collagen type 1 scaffold grafted onto an injured myocardium induced neo-vessel formation and reduced LV remodeling. Treatment with G-CSF further increased the number of vessels in the myocardium, possibly due to mobilization of bone marrow cells.

Asunto(s)

Colágeno Tipo I , Infarto del Miocardio/cirugía , Neovascularización Fisiológica , Ingeniería de Tejidos/métodos , Remodelación Ventricular , Animales , Masculino , Ratas , Ratas Endogámicas F344 , Factores de Tiempo

RESUMEN

BACKGROUND: Altering the renin-angiotensin aldosterone system improve mortality in heart failure (HF) in part through an improvement in nitric oxide (NO)-mediated endothelial function. This study examined if spironolactone affects endothelial nitric oxide synthase (eNOS) and NO-mediated vasorelaxation in HF. METHODS AND RESULTS: Rats with HF after coronary artery ligation were treated with spironolactone for 4 weeks. Rats with HF had a decrease (P < .05) in left ventricular (LV) systolic pressure (130 +/- 7 versus 118 +/- 6 mm Hg) and LV pressure with respect to time (9,122 +/- 876 versus 4,500 +/- 1971 mm Hg/second) with an increase in LV end-diastolic pressure (4 +/- 2 versus 23 +/- 8 mm Hg). Spironolactone did not affect hemodynamics but it improved (P < .05) endothelial-dependent vasorelaxation at more than 10(-8) M acetylcholine that was abolished with N(G)-monomethyl-L-arginine. The eNOS levels were decreased (P < .05) in the LV and the aorta; spironolactone restored LV and aortic eNOs levels to normal. CONCLUSION: Spironolactone prevents the decrease in eNOS in the LV and aorta and improves NO-dependent vasorelaxation, suggesting that one potential mechanism of spironolactone is an improvement in vasoreactivity mediated though an increase in NO.

Asunto(s)

Endotelio Vascular/efectos de los fármacos , Insuficiencia Cardíaca/tratamiento farmacológico , Antagonistas de Receptores de Mineralocorticoides/uso terapéutico , Óxido Nítrico Sintasa/biosíntesis , Espironolactona/uso terapéutico , Vasodilatación/efectos de los fármacos , Animales , Insuficiencia Cardíaca/fisiopatología , Hemodinámica , Masculino , Antagonistas de Receptores de Mineralocorticoides/farmacología , Óxido Nítrico Sintasa/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Sistema Renina-Angiotensina/efectos de los fármacos , Espironolactona/farmacología

RESUMEN

BACKGROUND: For prolonged VF, perfusion of the myocardium by pre-shock chest compressions can improve myocardial readiness for successful defibrillation. Characteristics of the VF waveform correlate with the duration of VF when there is no structural heart disease. A "smart" automated external defibrillator (AED) could therefore analyze the VF waveform, determine if VF has been prolonged, and then direct rescuers to either deliver a shock first or chest compressions first. We hypothesized that ischemic heart failure might alter the waveform content of ventricular fibrillation compared with normal hearts, complicating the determination of VF duration. METHODS: Myocardial infarction was induced by ligating the proximal left coronary artery. Six weeks later, VF was then induced in 10 rats with myocardial infarction and heart failure (MI-CHF) and 9 control rats. Waveforms were analyzed for total signal amplitude, median frequency, dominant frequency and bandwidth (the frequency interval containing 50% of the total amplitude about the median frequency). RESULTS: All of these VF waveform characteristics were altered substantially in MI-CHF rats compared to normal controls. In particular, MI-CHF rats had decreased signal amplitude early in VF (p=0.02), a broader bandwidth (p=0.001) and different frequency characteristics over time (p<0.001). CONCLUSIONS: VF waveforms vary over time in a typical manner among rats with and without ischemic heart failure. However, the time-course and waveform characteristics of ventricular fibrillation are altered in rats with myocardial infarctions and ischemic heart failure compared to normal controls. These findings have important implications regarding the use of waveform analyses to determine the duration of VF.

Asunto(s)

Corazón/fisiología , Infarto del Miocardio/fisiopatología , Fibrilación Ventricular/fisiopatología , Animales , Análisis de Fourier , Hemodinámica , Ratas , Ratas Sprague-Dawley

RESUMEN

This study was designed to determine if the thyroid hormone analog 3,5 diiodothyropropionic acid (DITPA), now in clinical trials for heart failure, alters endothelial function after myocardial infarction (MI). Three weeks after MI, adult Sprague-Dawley rats were randomly assigned to DITPA (375 microg/100 g subcutaneous) or no treatment of 3 weeks. In MI rats, left ventricular (LV) end-diastolic pressure and LV dP/dt decreased (P < 0.05). DITPA did not change MAP (87 +/- 10 versus 90 +/- 7 mm Hg) or LV end-diastolic pressure (23 +/- 3 versus 19 +/- 9 mm Hg) but did lower (P < 0.05) LV dP/dt (4,633 +/- 797 versus 3,650 +/- 1,236 mm Hg/s). In aortic segments from MI rats, DITPA enhanced the acetylcholine dependent vasorelaxation (59 +/- 11% at 10(-4) M, P < 0.05) and isoproterenol induced vasorelaxation (57 +/- 13% at 10(-4) M, P < 0.05). The increases in vasorelaxation were blocked with l-NAME and restored with L-arginine. Treatment with DITPA increased (P < 0.05) eNOS protein content in aortic tissue from sham rats (3.8 +/- 2.8 to 44.5 +/- 7.1 integrated intensity units (II)/microg) and in MI rats (5.3 +/- 3.4 to 28.3 +/- 8.9 II/microg). In endothelial cells, 24 hours' treatment with DITPA (10 microM) increased (P < 0.01) eNOS protein expression from 22.1 +/- 4.8 to 52.7 +/- 16.8 II/microg protein and DITPA (20 microM) increased eNOS to 49.1+/- 15.2 II/microg protein. The thyroid analog DITPA enhances endothelial nitric oxide and beta-adrenergic-mediated vasorelaxation by increasing nitric oxide in the vasculature.

Asunto(s)

Diyodotironinas/farmacología , Endotelio Vascular/metabolismo , Infarto del Miocardio/tratamiento farmacológico , Óxido Nítrico/fisiología , Propionatos/farmacología , Receptores Adrenérgicos beta/fisiología , Vasodilatadores/farmacología , Acetilcolina/farmacología , Animales , Bovinos , Células Cultivadas , Vasos Coronarios/efectos de los fármacos , Vasos Coronarios/fisiopatología , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/fisiopatología , Hemodinámica/efectos de los fármacos , Isoproterenol/farmacología , Infarto del Miocardio/complicaciones , Infarto del Miocardio/fisiopatología , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/biosíntesis , Óxido Nítrico Sintasa de Tipo III , Nitroprusiato/farmacología , Ratas , Ratas Sprague-Dawley , Función Ventricular Izquierda/efectos de los fármacos

RESUMEN

Coronary artery disease (CAD) remains the leading cause of death in the Western world. The high impact of its main sequelae, acute myocardial infarction and congestive heart failure (CHF), on the quality of life of patients and the cost of health care drives the search for new therapies. The recent finding that stem cells contribute to neovascularization and possibly improve cardiac function after myocardial infarction makes stem cell therapy the most highly active research area in cardiology. Although the concept of stem cell therapy may revolutionize heart failure treatment, several obstacles need to be addressed. To name a few: 1) Which patient population should be considered for stem cell therapy? 2) What type of stem cell should be used? 3) What is the best route for cell delivery? 4) What is the optimum number of cells that should be used to achieve functional effects? 5) Is stem cell therapy safer and more effective than conventional therapies? The published studies vary significantly in design, making it difficult to draw conclusions on the efficacy of this treatment. For example, different models of ischemia, species of donors and recipients, techniques of cell delivery, cell types, cell numbers and timing of the experiments have been used. However, these studies highlight the landmark concept that stem cell therapy may play a major role in treating cardiovascular diseases in the near future. It should be noted that stem cell therapy is not limited to the treatment of ischemic cardiac disease. Non-ischemic cardiomyopathy, peripheral vascular disease, and aging may be treated by stem cells. Stem cells could be used as vehicle for gene therapy and eliminate the use of viral vectors. Finally, stem cell therapy may be combined with pharmacological, surgical, and interventional therapy to improve outcome. Here we attempt a systematic overview of the science of stem cells and their effects when transplanted into ischemic myocardium.

Asunto(s)

Enfermedad Coronaria/terapia , Isquemia Miocárdica/terapia , Trasplante de Células Madre/métodos , Animales , Ensayos Clínicos como Asunto , Humanos , Células Madre/fisiología