RESUMEN
BACKGROUND: Magnetic resonance imaging (MRI) in the CArdiosphere-Derived aUtologous stem CElls to reverse ventricUlar dySfunction (CADUCEUS) trial revealed that cardiosphere-derived cells (CDCs) decrease scar size and increase viable myocardium after myocardial infarction (MI), but MRI has not been validated as an index of regeneration after cell therapy. We tested the validity of contrast-enhanced MRI in quantifying scarred and viable myocardium after cell therapy in a porcine model of convalescent MI. METHODS AND RESULTS: Yucatan minipigs underwent induction of MI and 2-3 weeks later were randomized to receive intracoronary infusion of 12.5×10(6) mismatched allogeneic CDCs or vehicle. Allogeneic CDCs induced mild local mononuclear infiltration but no systemic immunogenicity. MRI revealed that allogeneic CDCs attenuated remodeling, improved global and regional function, decreased scar size, and increased viable myocardium compared with placebo 2 months post-treatment. Extensive histological analysis validated quantitatively the MRI measurements of scar size, scar mass, and viable mass. CDCs neither altered gadolinium contrast myocardial kinetics nor induced changes in vascular density or architecture in viable and scarred myocardium. Histology demonstrated that CDCs lead to cardiomyocyte hyperplasia in the border zone, consistent with the observed stimulation of endogenous regenerative mechanisms (cardiomyocyte cycling, upregulation of endogenous progenitors, angiogenesis). CONCLUSIONS: Contrast-enhanced MRI accurately measures scarred and viable myocardium after cell therapy in a porcine model of convalescent MI. MRI represents a useful tool for assessing dynamic changes in the infarct and monitoring regenerative efficacy.
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Tratamiento Basado en Trasplante de Células y Tejidos , Corazón/fisiopatología , Imagen por Resonancia Magnética/métodos , Infarto del Miocardio/terapia , Miocardio/patología , Regeneración/fisiología , Animales , Cicatriz/patología , Modelos Animales de Enfermedad , Gadolinio , Sistema Inmunológico/fisiopatología , Masculino , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Porcinos , Porcinos Enanos , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND: Infusion of allogeneic cardiosphere-derived cells (allo-CDCs) postreperfusion elicits cardioprotective cellular postconditioning in pigs with acute myocardial infarction. However, the long-term effects of allo-CDCs have not been assessed. We performed a placebo-controlled pivotal study for long-term evaluation, as well as shorter-term mechanistic studies. METHODS AND RESULTS: Minipigs underwent 1.5-hour mid-left anterior descending balloon occlusion followed by reperfusion and were randomized to receive intracoronary allo-CDCs or vehicle 30 minutes postreperfusion. Left ventriculography (LVG) demonstrated preserved ejection fraction (EF) and attenuation of LV remodeling in CDC-treated pigs. Pigs underwent cardiac magnetic resonance imaging (MRI) and LVG 1 hour and 8 weeks after therapy to evaluate efficacy. MRI showed improvement of EF and attenuation of LV remodeling immediately after allo-CDC infusion. In addition, allo-CDCs improved regional function and decreased hypertrophy 2 months post-treatment. Histological analysis revealed increased myocardial salvage index, enhanced vascularity, sustained reductions in infarct size/area at risk and scar transmurality, and attenuation of collagen deposition in the infarct zone of allo-CDC-treated pigs at 2 months. Allo-CDCs did not evoke lymphohistiocytic infiltration or systemic humoral memory response. Short-term experiments designed to probe mechanism revealed antiapoptotic effects of allo-CDCs on cardiomyocytes and increases in cytoprotective macrophages, but no increase in overall inflammatory cell infiltration 2 hours after cell therapy. CONCLUSIONS: Allo-CDC infusion postreperfusion is safe, improves cardiac function, and attenuates scar size and remodeling. The favorable effects persist for at least 2 months after therapy. Thus, cellular postconditioning confers not only acute cardioprotection, but also lasting structural and functional benefits.
Asunto(s)
Infarto del Miocardio/terapia , Daño por Reperfusión Miocárdica/prevención & control , Reperfusión Miocárdica , Miocardio/patología , Miocitos Cardíacos/trasplante , Animales , Apoptosis , Biopsia , Células Cultivadas , Modelos Animales de Enfermedad , Macrófagos/patología , Imagen por Resonancia Magnética , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Reperfusión Miocárdica/efectos adversos , Daño por Reperfusión Miocárdica/patología , Daño por Reperfusión Miocárdica/fisiopatología , Miocitos Cardíacos/patología , Volumen Sistólico , Porcinos , Porcinos Enanos , Factores de Tiempo , Trasplante Homólogo , Función Ventricular Izquierda , Remodelación VentricularRESUMEN
BACKGROUND: Intracoronary delivery of cardiosphere-derived cells (CDCs) has been demonstrated to be safe and effective in porcine and human chronic myocardial infarction. However, intracoronary delivery of CDCs after reperfusion in acute myocardial infarction has never been assessed in a clinically-relevant large animal model. We tested CDCs as adjunctive therapy to reperfusion in a porcine model of myocardial infarction. METHODS AND RESULTS: First, escalating doses (5, 7.5, and 10 million cells) of allogeneic CDCs were administered intracoronary 30 minutes after reperfusion. Forty-eight hours later, left ventriculography was performed and animals euthanized to measure area at risk, infarct size (IS), and microvascular obstruction. Second, identical end points were measured in a pivotal study of minipigs (n=14) that received 8.5 to 9 million allogeneic CDCs, placebo solution, or sham. Multiple indicators of cardioprotection were observed with 7.5 and 10 million allogeneic CDCs, but not 5 million CDCs, relative to control. In the pivotal study, IS, microvascular obstruction, cardiomyocyte apoptosis, and adverse left ventricular remodeling were all smaller in the CDC group than in sham or placebo groups. In addition, serum troponin I level at 24 hours was lower after CDC infusion than that in the placebo or sham groups, consistent with the histologically-demonstrated reduction in IS. CONCLUSIONS: Intracoronary delivery of allogeneic CDCs is safe, feasible, and effective in cardioprotection, reducing IS, preventing microvascular obstruction, and attenuating adverse acute remodeling. This novel cardioprotective effect, which we call cellular postconditioning, differs from previous strategies to reduce IS in that it works even when initiated with significant delay after reflow.
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Poscondicionamiento Isquémico/métodos , Infarto del Miocardio/terapia , Reperfusión Miocárdica , Trasplante de Células Madre/métodos , Animales , Vasos Coronarios , Modelos Animales de Enfermedad , Insuficiencia Cardíaca/cirugía , Inyecciones Intraarteriales , Infarto del Miocardio/complicaciones , Porcinos , Porcinos Enanos , Trasplante Homólogo , Remodelación Ventricular/fisiologíaRESUMEN
BACKGROUND: Epicardial injection of heart-derived cell products is safe and effective post-myocardial infarction (MI), but clinically-translatable transendocardial injection has never been evaluated. We sought to assess the feasibility, safety and efficacy of percutaneous transendocardial injection of heart-derived cells in porcine chronic ischemic cardiomyopathy. METHODS AND RESULTS: We studied a total of 89 minipigs; 63 completed the specified protocols. After NOGA-guided transendocardial injection, we quantified engraftment of escalating doses of allogeneic cardiospheres or cardiosphere-derived cells in minipigs (nâ=â22) post-MI. Next, a dose-ranging, blinded, randomized, placebo-controlled ("dose optimization") study of transendocardial injection of the better-engrafting product was performed in infarcted minipigs (nâ=â16). Finally, the superior product and dose (150 million cardiospheres) were tested in a blinded, randomized, placebo-controlled ("pivotal") study (nâ=â22). Contrast-enhanced cardiac MRI revealed that all cardiosphere doses preserved systolic function and attenuated remodeling. The maximum feasible dose (150 million cells) was most effective in reducing scar size, increasing viable myocardium and improving ejection fraction. In the pivotal study, eight weeks post-injection, histopathology demonstrated no excess inflammation, and no myocyte hypertrophy, in treated minipigs versus controls. No alloreactive donor-specific antibodies developed over time. MRI showed reduced scar size, increased viable mass, and attenuation of cardiac dilatation with no effect on ejection fraction in the treated group compared to placebo. CONCLUSIONS: Dose-optimized injection of allogeneic cardiospheres is safe, decreases scar size, increases viable myocardium, and attenuates cardiac dilatation in porcine chronic ischemic cardiomyopathy. The decreases in scar size, mirrored by increases in viable myocardium, are consistent with therapeutic regeneration.
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Cardiomiopatías/complicaciones , Cardiomiopatías/terapia , Cicatriz/patología , Endocardio/patología , Isquemia Miocárdica/terapia , Miocitos Cardíacos/trasplante , Esferoides Celulares/trasplante , Administración Cutánea , Animales , Cardiomiopatías/inmunología , Cardiomiopatías/patología , Catéteres , Cicatriz/complicaciones , Dilatación , Femenino , Inyecciones , Imagen por Resonancia Magnética , Masculino , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/inmunología , Isquemia Miocárdica/patología , Miocitos Cardíacos/citología , Regeneración , Esferoides Celulares/citología , Análisis de Supervivencia , Sus scrofa , Trasplante Homólogo/efectos adversosRESUMEN
BACKGROUND: Pacemaker-dependent patients with device infection require temporary pacing while the infection is treated. External transthoracic pacing is painful and variably effective, while temporary pacing leads are susceptible to superinfection. OBJECTIVE: To create a biological pacemaker delivered via venous catheters in a porcine model of complete heart block, providing a temporary alternative/adjunct to external pacing devices without additional indwelling hardware. METHODS: Complete atrioventricular (AV) nodal block was induced in pigs by radiofrequency ablation after the implantation of a single-chamber electronic pacemaker to maintain a ventricular backup rate of 50 beats/min. An adenoviral vector cocktail (K(AAA) + H2), expressing dominant-negative inward rectifier potassium channel (Kir2.1AAA) and hyperpolarization-activated cation channel (HCN2) genes, was injected into the AV junctional region via a NOGA Myostar catheter advanced through the femoral vein. RESULTS: Animals injected with K(AAA) + H2 maintained a physiologically relevant ventricular rate of 93.5 ± 7 beats/min (n = 4) compared with control animals (average rate, 59.4 ± 4 beats/min; n = 6 at day 7 postinjection; P <.05). Backup electronic pacemaker utilization decreased by almost 4-fold in the K(AAA) + H2 group compared with the control (P <.05), an effect maintained for the entire 14-day window. In contrast to the efficacy of gene delivery into the AV junctional region, open-chest, direct injection of K(AAA) + H2 (or its individual vectors) into the ventricular myocardium failed to elicit significant pacemaker activity. CONCLUSIONS: The right-sided delivery of K(AAA) + H2 to the AV junctional region provided physiologically relevant biological pacing over a 14-day period. Our approach may provide temporary, bridge-to-device pacing for the effective clearance of infection prior to the reimplantation of a definitive electronic pacemaker.
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Relojes Biológicos/genética , Vectores Genéticos , Bloqueo Cardíaco/terapia , Adenoviridae/genética , Animales , Ablación por Catéter , Modelos Animales de Enfermedad , Técnicas Electrofisiológicas Cardíacas , Técnicas de Transferencia de Gen , Proteínas Fluorescentes Verdes , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización , Canales Iónicos/genética , Canales de Potasio de Rectificación Interna/genética , PorcinosRESUMEN
OBJECTIVES: The purpose of this study was to test the safety and efficacy of direct injection of cardiosphere-derived cells (CDCs) and their 3-dimensional precursors, cardiospheres, for cellular cardiomyoplasty in a mini-pig model of heart failure after myocardial infarction. BACKGROUND: Intracoronary administration of CDCs has been demonstrated to reduce infarct size and improve hemodynamic indexes in the mini-pig model, but intramyocardial injection of CDCs or cardiospheres has not been assessed in large animals. METHODS: Autologous cardiospheres or CDCs grown from endomyocardial biopsies were injected through thoracotomy 4 weeks after anteroseptal myocardial infarction. Engraftment optimization with luciferase-labeled CDCs guided the choice of cell dose (0.5 million cells/site) and target tissue (20 peri-infarct sites). Pigs were randomly allocated to placebo (n = 11), cardiospheres (n = 8), or CDCs (n = 10). Functional data were acquired before injection and again 8 weeks later, after which organs were harvested for histopathology. RESULTS: Beyond the immediate perioperative period, all animals survived to protocol completion. Ejection fraction was equivalent at baseline, but at 8 weeks was higher than placebo in both of the cell-treated groups (placebo vs. CDC, p = 0.01; placebo vs. cardiospheres, p = 0.01). Echocardiographic and hemodynamic indexes of efficacy improved disproportionately with cardiospheres; likewise, adverse remodeling was more attenuated with cardiospheres than with CDCs. Provocative electrophysiologic testing showed no differences among groups, and no tumors were found. CONCLUSIONS: Dosage-optimized direct injection of cardiospheres or CDCs is safe and effective in preserving ventricular function in porcine ischemic cardiomyopathy. Although CDCs and cardiospheres have equivalent effects on left ventricular ejection fraction, cardiospheres are superior in improving hemodynamics and regional function, and in attenuating ventricular remodeling.
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Insuficiencia Cardíaca/cirugía , Trasplante de Células Madre Mesenquimatosas/métodos , Infarto del Miocardio/complicaciones , Miocitos Cardíacos/trasplante , Remodelación Ventricular/fisiología , Análisis de Varianza , Animales , Modelos Animales de Enfermedad , Femenino , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/mortalidad , Inyecciones Intralesiones , Distribución Aleatoria , Valores de Referencia , Factores de Riesgo , Volumen Sistólico , Tasa de Supervivencia , Porcinos , Porcinos Enanos , Toracostomía/métodos , Trasplante Autólogo , Resultado del TratamientoRESUMEN
Focal adhesion kinase (FAK) is an important mediator of integrin signaling in the regulation of cell adhesion, migration, survival, and proliferation. Here we report the identification of the transcription factor KLF8 as a target of FAK in cell cycle regulation. KLF8 is induced by FAK and decreased by FAK dominant-negative mutant DeltaC14. Overexpression of KLF8 increases cell cycle progression, whereas inhibition of endogenous KLF8 by siRNA reduces it. Cyclin D1 promoter is identified as a target of KLF8, which is activated both directly by KLF8 binding to the GT box A and by an indirect mechanism through its repression of a potential inhibitory regulator of cyclin D1. Transcription activation of cyclin D1 by FAK requires both Ets family and KLF8 factors in a temporally differential manner. Together, our data provide further insights into molecular mechanism for FAK to regulate cell cycle progression.