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Pulmonary vascular impedance (PVZ) describes RV afterload in the frequency domain and has not been studied extensively in LVAD patients. We sought to determine (1) feasibility of calculating a composite (c)PVZ using standard of care (SoC), asynchronous, pulmonary artery pressure (PAP) and flow (PAQ) waveforms; and (2) if chronic right ventricular failure (RVF) post-LVAD implant was associated with changes in perioperative cPVZ.PAP and PAQ were obtained via SoC procedures at three landmarks: T(1), Retrospectively, pre-operative with patient conscious; and T(2) and T(3), prospectively with patient anesthetized, and either pre-sternotomy or chest open with LVAD, respectively. Additional PAP's were taken at T(4), following chest closure; and T(5), 4-24 h post chest closure. Harmonics (z) were calculated by Fast Fourier Transform (FFT) with cPVZ(z) = FFT(PAP)/FFT(PAQ). Total pulmonary resistance Z(0); characteristic impedance Zc, mean of cPVZ(2-4); and vascular stiffness PVS, sum of cPVZ(1,2), were compared at T(1,2,3) between +/-RVF groups.Out of 51 patients, nine experienced RVF. Standard hemodynamics and changes in cPVZ-derived parameters were not significant between groups at any T.In conclusion, cPVZ calculated from SoC measures is possible. Although data that could be obtained were limited it suggests no difference in RV afterload for RVF patients post-implant. If confirmed in larger studies, focus should be placed on cardiac function in these subjects.
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Insuficiência Cardíaca , Coração Auxiliar , Humanos , Estudos Retrospectivos , Impedância Elétrica , Estudos de Viabilidade , HemodinâmicaRESUMO
Cardiomyopathy is a progressive disease of the myocardium leading to impaired contractility. Genotoxic cancer therapies are known to be potent drivers of cardiomyopathy, whereas causes of spontaneous disease remain unclear. To test the hypothesis that endogenous genotoxic stress contributes to cardiomyopathy, we deleted the DNA repair gene Ercc1 specifically in striated muscle using a floxed allele of Ercc1 and mice expressing Cre under control of the muscle-specific creatinine kinase (Ckmm) promoter or depleted systemically (Ercc1-/D mice). Ckmm-Cre+/- ;Ercc1-/fl mice expired suddenly of heart disease by 7 months of age. As young adults, the hearts of Ckmm-Cre+/- ;Ercc1-/fl mice were structurally and functionally normal, but by 6-months-of-age, there was significant ventricular dilation, wall thinning, interstitial fibrosis, and systolic dysfunction indicative of dilated cardiomyopathy. Cardiac tissue from the tissue-specific or systemic model showed increased apoptosis and cardiac myocytes from Ckmm-Cre+/- ;Ercc1-/fl mice were hypersensitive to genotoxins, resulting in apoptosis. p53 levels and target gene expression, including several antioxidants, were increased in cardiac tissue from Ckmm-Cre+/- ;Ercc1-/fl and Ercc1-/D mice. Despite this, cardiac tissue from older mutant mice showed evidence of increased oxidative stress. Genetic or pharmacologic inhibition of p53 attenuated apoptosis and improved disease markers. Similarly, overexpression of mitochondrial-targeted catalase improved disease markers. Together, these data support the conclusion that DNA damage produced endogenously can drive cardiac disease and does so mechanistically via chronic activation of p53 and increased oxidative stress, driving cardiac myocyte apoptosis, dilated cardiomyopathy, and sudden death.
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Cardiomiopatia Dilatada , Miócitos Cardíacos , Camundongos , Animais , Miócitos Cardíacos/metabolismo , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Miocárdio/metabolismo , Reparo do DNARESUMO
Increased proliferation and survival of cells in small pulmonary arteries (PAs) drive pulmonary arterial hypertension (PAH). Because cell growth mediated by the mTOR-containing mTORC1 complex is inhibited by tuberous sclerosis complex 2 (TSC2), we investigated the role of this GTPase-activating protein in PAH pathology. TSC2 abundance was decreased in remodeled small PAs and PA vascular smooth muscle cells (PAVSMCs) from patients with PAH or from rodent pulmonary hypertension (PH) models, as well as PAVSMCs maintained on substrates that reproduced pathology-induced stiffness. Accordingly, mice with smooth muscle-specific reduction in TSC2 developed PH. At the molecular level, decreased TSC2 abundance led to stiffness-induced PAVSMC proliferation, increased abundance of the mechanosensitive transcriptional coactivators YAP/TAZ, and enhanced mTOR kinase activity. Moreover, extracellular matrix (ECM) produced by TSC2-deficient PAVSMCs stimulated the proliferation of nondiseased PA adventitial fibroblasts and PAVSMCs through fibronectin and its receptor, the α5ß1 integrin. Reconstituting TSC2 in PAVSMCs from patients with PAH through overexpression or treatment with the SIRT1 activator SRT2104 decreased YAP/TAZ abundance, mTOR activity, and ECM production, as well as inhibited proliferation and induced apoptosis. In two rodent models of PH, SRT2104 treatment restored TSC2 abundance, attenuated pulmonary vascular remodeling, and ameliorated PH. Thus, TSC2 in PAVSMCs integrates ECM composition and stiffness with pro-proliferative and survival signaling, and restoring TSC2 abundance could be an attractive therapeutic option to treat PH.
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Hipertensão Pulmonar , Esclerose Tuberosa , Animais , Camundongos , Proliferação de Células , Matriz Extracelular , Hipertensão Pulmonar/genética , HumanosRESUMO
RATIONALE: The MSTs (mammalian Ste20-like kinases) 1/2 are members of the HIPPO pathway that act as growth suppressors in adult proliferative diseases. Pulmonary arterial hypertension (PAH) manifests by increased proliferation and survival of pulmonary vascular cells in small PAs, pulmonary vascular remodeling, and the rise of pulmonary arterial pressure. The role of MST1/2 in PAH is currently unknown. OBJECTIVE: To investigate the roles and mechanisms of the action of MST1 and MST2 in PAH. METHODS AND RESULTS: Using early-passage pulmonary vascular cells from PAH and nondiseased lungs and mice with smooth muscle-specific tamoxifen-inducible Mst1/2 knockdown, we found that, in contrast to canonical antiproliferative/proapoptotic roles, MST1/2 act as proproliferative/prosurvival molecules in human PAH pulmonary arterial vascular smooth muscle cells and pulmonary arterial adventitial fibroblasts and support established pulmonary vascular remodeling and pulmonary hypertension in mice with SU5416/hypoxia-induced pulmonary hypertension. By using unbiased proteomic analysis, gain- and loss-of function approaches, and pharmacological inhibition of MST1/2 kinase activity by XMU-MP-1, we next evaluated mechanisms of regulation and function of MST1/2 in PAH pulmonary vascular cells. We found that, in PAH pulmonary arterial adventitial fibroblasts, the proproliferative function of MST1/2 is caused by IL-6-dependent MST1/2 overexpression, which induces PSMC6-dependent downregulation of forkhead homeobox type O 3 and hyperproliferation. In PAH pulmonary arterial vascular smooth muscle cells, MST1/2 acted via forming a disease-specific interaction with BUB3 and supported ECM (extracellular matrix)- and USP10-dependent BUB3 accumulation, upregulation of Akt-mTORC1, cell proliferation, and survival. Supporting our in vitro observations, smooth muscle-specific Mst1/2 knockdown halted upregulation of Akt-mTORC1 in small muscular PAs of mice with SU5416/hypoxia-induced pulmonary hypertension. CONCLUSIONS: Together, this study describes a novel proproliferative/prosurvival role of MST1/2 in PAH pulmonary vasculature, provides a novel mechanistic link from MST1/2 via BUB3 and forkhead homeobox type O to the abnormal proliferation and survival of pulmonary arterial vascular smooth muscle cells and pulmonary arterial adventitial fibroblasts, remodeling and pulmonary hypertension, and suggests new target pathways for therapeutic intervention.
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Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Hipertensão Pulmonar , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Hipertensão Arterial Pulmonar , Animais , Proliferação de Células , Células Cultivadas , Hipertensão Pulmonar/metabolismo , Hipóxia/metabolismo , Mamíferos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Miócitos de Músculo Liso/metabolismo , Proteômica , Proteínas Proto-Oncogênicas c-akt/metabolismo , Hipertensão Arterial Pulmonar/genética , Artéria Pulmonar/metabolismo , Remodelação Vascular/fisiologiaRESUMO
Goal: Create a semi-automated, graphical, stand-alone application that uses clinically available asynchronous pressure and Doppler velocity captures to rapidly calculate, display, and interpret the pulmonary vascular impedance (PVZ) spectra. Methods: MATLAB-based software was written to analyze PVZ by creating a composite PVZ (cPVZ) spectra comprised of asynchronous screen captures of pulmonary arterial pressure and pulmonary arterial pulsed-wave Doppler velocity waveforms obtained during standard of care procedures. The pressure waveform, Doppler frequency envelopes, and ECG signals were re-digitized via automated border detection. cPVZ of averaged representative beats was calculated in the frequency domain via Fast Fourier Transform, and plotted vs harmonic z. Results: Successful generation of impedance spectra (PVZ(z)), where z is the harmonic, and additional parameters for characteristic impedance (Zc) and stiffness (Zs) were calculated as the mean of PVZ(2-4), and the sum of PVZ (1, 2), respectively. Conclusions: A graphically driven analysis of PVZ, calculated from standard of care right heart catheterization and echocardiography is possible. This system can help characterize both the steady and pulsatile components of right ventricular (RV) afterload in the clinical setting.
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Healthy aging has been associated with alterations in pulmonary vascular and right ventricular (RV) hemodynamics, potentially leading to RV remodeling. Despite the current evidence suggesting an association between aging and alterations in RV function and higher prevalence of pulmonary hypertension in the elderly, limited data exist on age-related differences in RV structure and biomechanics. In this work, we report our preliminary findings on the effects of healthy aging on RV structure, function, and biomechanical properties. Hemodynamic measurements, biaxial mechanical testing, constitutive modeling, and quantitative transmural histological analysis were employed to study two groups of male Sprague-Dawley rats: control (11 weeks) and aging (80 weeks). Aging was associated with increases in RV peak pressures (+17%, p = 0.017), RV contractility (+52%, p = 0.004), and RV wall thickness (+38%, p = 0.001). Longitudinal realignment of RV collagen (16.4°, p = 0.013) and myofibers (14.6°, p = 0.017) were observed with aging, accompanied by transmural cardiomyocyte loss and fibrosis. Aging led to increased RV myofiber stiffness (+141%, p = 0.003), in addition to a bimodal alteration in the biaxial biomechanical properties of the RV free wall, resulting in increased tissue-level stiffness in the low-strain region, while progressing into decreased stiffness at higher strains. Our results demonstrate that healthy aging may modulate RV remodeling via increased peak pressures, cardiomyocyte loss, fibrosis, fiber reorientation, and altered mechanical properties in male Sprague-Dawley rats. Similarities were observed between aging-induced remodeling patterns and those of RV remodeling in pressure overload. These findings may help our understanding of age-related changes in the cardiovascular fitness and response to disease.
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OBJECTIVE: Chronic hemolysis is a hallmark of sickle cell disease (SCD) and a driver of vasculopathy; however, the mechanisms contributing to hemolysis remain incompletely understood. Although XO (xanthine oxidase) activity has been shown to be elevated in SCD, its role remains unknown. XO binds endothelium and generates oxidants as a byproduct of hypoxanthine and xanthine catabolism. We hypothesized that XO inhibition decreases oxidant production leading to less hemolysis. Approach and Results: Wild-type mice were bone marrow transplanted with control (AA) or sickle (SS) Townes bone marrow. After 12 weeks, mice were treated with 10 mg/kg per day of febuxostat (Uloric), Food and Drug Administration-approved XO inhibitor, for 10 weeks. Hematologic analysis demonstrated increased hematocrit, cellular hemoglobin, and red blood cells, with no change in reticulocyte percentage. Significant decreases in cell-free hemoglobin and increases in haptoglobin suggest XO inhibition decreased hemolysis. Myographic studies demonstrated improved pulmonary vascular dilation and blunted constriction, indicating improved pulmonary vasoreactivity, whereas pulmonary pressure and cardiac function were unaffected. The role of hepatic XO in SCD was evaluated by bone marrow transplanting hepatocyte-specific XO knockout mice with SS Townes bone marrow. However, hepatocyte-specific XO knockout, which results in >50% diminution in circulating XO, did not affect hemolysis levels or vascular function, suggesting hepatocyte-derived elevation of circulating XO is not the driver of hemolysis in SCD. CONCLUSIONS: Ten weeks of febuxostat treatment significantly decreased hemolysis and improved pulmonary vasoreactivity in a mouse model of SCD. Although hepatic XO accounts for >50% of circulating XO, it is not the source of XO driving hemolysis in SCD.
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Anemia Falciforme/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Eritrócitos/efeitos dos fármacos , Febuxostat/farmacologia , Hemodinâmica/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Artéria Pulmonar/efeitos dos fármacos , Xantina Oxidase/antagonistas & inibidores , Anemia Falciforme/sangue , Anemia Falciforme/enzimologia , Anemia Falciforme/fisiopatologia , Animais , Modelos Animais de Doenças , Eritrócitos/enzimologia , Fígado/enzimologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Artéria Pulmonar/enzimologia , Artéria Pulmonar/fisiopatologia , Função Ventricular/efeitos dos fármacos , Xantina Oxidase/genética , Xantina Oxidase/metabolismoRESUMO
BackgroundPulmonary hypertension (PH) results in increased right ventricular (RV) afterload and ventricular remodeling. Sacubitril/valsartan (sac/val) is a dual acting drug, composed of the neprilysin inhibitor sacubitril and the angiotensin receptor blocker valsartan, that has shown promising outcomes in reducing the risk of death and hospitalization for chronic systolic left ventricular heart failure. In this study, we aimed to examine if angiotensin receptor-neprilysin inhibition using sac/val attenuates RV remodeling in PH.Methods and ResultsRV pressure overload was induced in Sprague-Dawley rats via banding the main pulmonary artery. Three different cohorts of controls, placebo-treated PH, and sac/val-treated PH were studied in a 21-day treatment window. Terminal invasive hemodynamic measurements, quantitative histological analysis, biaxial mechanical testing, and constitutive modeling were employed to conduct a multiscale analysis on the effects of sac/val on RV remodeling in PH. Sac/val treatment decreased RV maximum pressures (29% improvement, P=0.002), improved RV contractile (30%, P=0.012) and relaxation (29%, P=0.043) functions, reduced RV afterload (35% improvement, P=0.016), and prevented RV-pulmonary artery uncoupling. Furthermore, sac/val attenuated RV hypertrophy (16% improvement, P=0.006) and prevented transmural reorientation of RV collagen and myofibers (P=0.011). The combined natriuresis and vasodilation resulting from sac/val led to improved RV biomechanical properties and prevented increased myofiber stiffness in PH (61% improvement, P=0.032).ConclusionsSac/val may prevent maladaptive RV remodeling in a pressure overload model via amelioration of RV pressure rise, hypertrophy, collagen, and myofiber reorientation as well as tissue stiffening both at the tissue and myofiber level.
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Aminobutiratos/farmacologia , Antagonistas de Receptores de Angiotensina/farmacologia , Hipertensão Pulmonar/tratamento farmacológico , Hipertrofia Ventricular Direita/prevenção & controle , Inibidores de Proteases/farmacologia , Tetrazóis/farmacologia , Disfunção Ventricular Direita/prevenção & controle , Função Ventricular Direita/efeitos dos fármacos , Remodelação Ventricular/efeitos dos fármacos , Animais , Fenômenos Biomecânicos , Compostos de Bifenilo , Colágeno/metabolismo , Modelos Animais de Doenças , Combinação de Medicamentos , Hemodinâmica/efeitos dos fármacos , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/patologia , Hipertensão Pulmonar/fisiopatologia , Hipertrofia Ventricular Direita/metabolismo , Hipertrofia Ventricular Direita/patologia , Hipertrofia Ventricular Direita/fisiopatologia , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Neprilisina/antagonistas & inibidores , Ratos Sprague-Dawley , Valsartana , Disfunção Ventricular Direita/metabolismo , Disfunção Ventricular Direita/patologia , Disfunção Ventricular Direita/fisiopatologiaRESUMO
BACKGROUND: The severity of pulmonary hypertension (PH) is monitored by measuring pulmonary vascular resistance, which is a steady-state measurement and ignores the pulsatile load encountered by the right ventricle (RV). Pulmonary vascular impedance (PVZ) can depict both steady-state and pulsatile forces, and thus may better predict clinical outcomes. We sought to calculate PVZ in patients with PH associated with heart failure with preserved ejection fraction who were administered inhaled sodium nitrite to better understand the acute effects on afterload. METHODS AND RESULTS: Fourteen patients with PH associated with heart failure with preserved ejection fraction underwent right heart catherization and were administered inhaled sodium nitrite. A Fourier transform was used to calculate PVZ for both before and after nitrite for comparison. Inhaled sodium nitrite decreased characteristic impedance (inversely related to proximal pulmonary artery compliance) and total work performed by the RV. RV efficiency improved, defined by a reduction in the total work divided by cardiac output. There was a mild decrease in pulmonary steady-state resistance after the administration of inhaled sodium nitrite, but this effect was not significant. CONCLUSIONS: PVZ analysis showed administration of inhaled sodium nitrite was associated with an improvement in pulmonary vascular compliance via a decrease in characteristic impedance, more so than pulmonary steady-state resistance. This effect was associated with improved RV efficiency and total work.
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Insuficiência Cardíaca , Hipertensão Pulmonar , Impedância Elétrica , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Hipertensão Pulmonar/tratamento farmacológico , Artéria Pulmonar , Nitrito de Sódio , Volume Sistólico , Resistência Vascular , Função Ventricular DireitaRESUMO
OBJECTIVE: Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle. CONCLUSIONS: Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.
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Epoprostenol/análogos & derivados , Insuficiência Cardíaca/complicações , Hiperglicemia/tratamento farmacológico , Hipertensão Pulmonar/tratamento farmacológico , Metformina/uso terapêutico , Volume Sistólico/fisiologia , Proteínas Quinases Ativadas por AMP/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/fisiologia , Animais , Anti-Hipertensivos , Dieta Hiperlipídica , Epoprostenol/uso terapêutico , Coração/efeitos dos fármacos , Coração/fisiopatologia , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/fisiopatologia , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/fisiopatologia , Hipoglicemiantes , Resistência à Insulina , Masculino , Síndrome Metabólica , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/fisiopatologia , Ratos , Receptores para Leptina/genéticaRESUMO
Our review in the 2008 volume of this journal detailed the use of mechanical circulatory support (MCS) for treatment of heart failure (HF). MCS initially utilized bladder-based blood pumps generating pulsatile flow; these pulsatile flow pumps have been supplanted by rotary blood pumps, in which cardiac support is generated via the high-speed rotation of computationally designed blading. Different rotary pump designs have been evaluated for their safety, performance, and efficacy in clinical trials both in the United States and internationally. The reduced size of the rotary pump designs has prompted research and development toward the design of MCS suitable for infants and children. The past decade has witnessed efforts focused on tissue engineering-based therapies for the treatment of HF. This review explores the current state and future opportunities of cardiac support therapies within our larger understanding of the treatment options for HF.
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Circulação Assistida/instrumentação , Circulação Assistida/métodos , Cardiologia/tendências , Insuficiência Cardíaca/terapia , Coração Auxiliar , Adulto , Circulação Assistida/tendências , Engenharia Biomédica/métodos , Cardiologia/métodos , Criança , Pré-Escolar , Humanos , Lactente , Desenho de Prótese , Ensaios Clínicos Controlados Aleatórios como Assunto , Engenharia Tecidual/métodosRESUMO
BACKGROUND: Right ventricular (RV) diastolic function has been associated with outcomes for patients with pulmonary hypertension; however, the relationship between biomechanics and hemodynamics in the right ventricle has not been studied. METHODS AND RESULTS: Rat models of RV pressure overload were obtained via pulmonary artery banding (PAB; control, n=7; PAB, n=5). At 3 weeks after banding, RV hemodynamics were measured using a conductance catheter. Biaxial mechanical properties of the RV free wall myocardium were obtained to extrapolate longitudinal and circumferential elastic modulus in low and high strain regions (E1 and E2, respectively). Hemodynamic analysis revealed significantly increased end-diastolic elastance (Eed) in PAB (control: 55.1 mm Hg/mL [interquartile range: 44.7-85.4 mm Hg/mL]; PAB: 146.6 mm Hg/mL [interquartile range: 105.8-155.0 mm Hg/mL]; P=0.010). Longitudinal E1 was increased in PAB (control: 7.2 kPa [interquartile range: 6.7-18.1 kPa]; PAB: 34.2 kPa [interquartile range: 18.1-44.6 kPa]; P=0.018), whereas there were no significant changes in longitudinal E2 or circumferential E1 and E2. Last, wall stress was calculated from hemodynamic data by modeling the right ventricle as a sphere: stress=Pressure×radius2×thickness. CONCLUSIONS: RV pressure overload in PAB rats resulted in an increase in diastolic myocardial stiffness reflected both hemodynamically, by an increase in Eed, and biomechanically, by an increase in longitudinal E1. Modest increases in tissue biomechanical stiffness are associated with large increases in Eed. Hemodynamic measurements of RV diastolic function can be used to predict biomechanical changes in the myocardium.
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Ventrículos do Coração/fisiopatologia , Hemodinâmica , Hipertensão Pulmonar/fisiopatologia , Pesquisa Translacional Biomédica/métodos , Disfunção Ventricular Direita/fisiopatologia , Função Ventricular Direita , Animais , Fenômenos Biomecânicos , Cateterismo Cardíaco , Constrição Patológica , Modelos Animais de Doenças , Módulo de Elasticidade , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/etiologia , Modelos Cardiovasculares , Artéria Pulmonar/fisiopatologia , Artéria Pulmonar/cirurgia , Ratos Sprague-Dawley , Fatores de Tempo , Disfunção Ventricular Direita/diagnóstico , Disfunção Ventricular Direita/etiologia , Pressão VentricularRESUMO
Pulmonary hypertension is characterized by pulmonary endothelial dysfunction. Previous work showed that systemic artery endothelial cells (ECs) express hemoglobin (Hb) α to control nitric oxide (NO) diffusion, but the role of this system in pulmonary circulation has not been evaluated. We hypothesized that up-regulation of Hb α in pulmonary ECs contributes to NO depletion and pulmonary vascular dysfunction in pulmonary hypertension. Primary distal pulmonary arterial vascular smooth muscle cells, lung tissue sections from unused donor (control) and idiopathic pulmonary artery (PA) hypertension lungs, and rat and mouse models of SU5416/hypoxia-induced pulmonary hypertension (PH) were used. Immunohistochemical, immunocytochemical, and immunoblot analyses and transfection, infection, DNA synthesis, apoptosis, migration, cell count, and protein activity assays were performed in this study. Cocultures of human pulmonary microvascular ECs and distal pulmonary arterial vascular smooth muscle cells, lung tissue from control and pulmonary hypertensive lungs, and a mouse model of chronic hypoxia-induced PH were used. Immunohistochemical, immunoblot analyses, spectrophotometry, and blood vessel myography experiments were performed in this study. We find increased expression of Hb α in pulmonary endothelium from humans and mice with PH compared with controls. In addition, we show up-regulation of Hb α in human pulmonary ECs cocultured with PA smooth muscle cells in hypoxia. We treated pulmonary ECs with a Hb α mimetic peptide that disrupts the association of Hb α with endothelial NO synthase, and found that cells treated with the peptide exhibited increased NO signaling compared with a scrambled peptide. Myography experiments using pulmonary arteries from hypoxic mice show that the Hb α mimetic peptide enhanced vasodilation in response to acetylcholine. Our findings reveal that endothelial Hb α functions as an endogenous scavenger of NO in the pulmonary endothelium. Targeting this pathway may offer a novel therapeutic target to increase endogenous levels of NO in PH.
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Materiais Biomiméticos/farmacologia , Células Endoteliais/metabolismo , Hemoglobina A/biossíntese , Hipertensão Pulmonar/tratamento farmacológico , Óxido Nítrico/metabolismo , Peptídeos/farmacologia , Artéria Pulmonar/metabolismo , Animais , Técnicas de Cocultura , Modelos Animais de Doenças , Células Endoteliais/patologia , Feminino , Humanos , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/patologia , Hipertensão Pulmonar/fisiopatologia , Masculino , Camundongos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Artéria Pulmonar/patologia , Artéria Pulmonar/fisiopatologia , Ratos , Regulação para Cima/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
BACKGROUND: Right ventricular failure (RVF) complicates 9% to 44% of left ventricular assist device (LVAD) implants post-operatively. Current prediction scores perform only modestly in validation studies, and do not include immune markers. Chemokines are inflammatory signaling molecules with a fundamental role in cardiac physiology and stress adaptation. In this study we investigated chemokine receptor regulation in LVAD recipients who develop RVF. METHODS: Expression of chemokine receptor (CCR) genes 3 to 8 were examined in the peripheral blood of 111 LVAD patients, collected 24 hours before implant. RNA was isolated using a PAXgene protocol. Gene expression was assessed using a targeted microarray (RT2 Profiler PCR Array; Qiagen). Results were expressed as polymerase chain reaction (PCR) cycles to threshold and normalized to the average of 3 control genes, glyceraldehyde phosphate dehydrogenase (GAPDH), hypoxanthine phosphoribosyltransferase 1 (HPRT1) and ß2-microglobulin (B2M). Secondary outcomes studied were 1-year mortality and long-term RV failure (RVF-LT). RESULTS: CCR3, CCR4, CCR6, CCR7 and CCR8 were downregulated in LVAD recipients with RVF. Within this cohort of patients, CCR4, CCR7 and CCR8 were further downregulated in those who required RV mechanical support. In addition, under-expression of CCR3 to CCR8 was independently associated with an increased risk of mortality at 1 year, even after adjusting for RVF. CCR expression did not predict RVF-LT in our patient cohort. CONCLUSIONS: Pre-LVAD CCR downregulation is associated with RVF and increased mortality after implant. Inflammatory signatures may play a major role in prognostication in this patient population.
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Insuficiência Cardíaca/sangue , Coração Auxiliar , Receptores de Quimiocinas/sangue , Medição de Risco , Disfunção Ventricular Direita/sangue , Biomarcadores/sangue , Feminino , Seguimentos , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Pennsylvania/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida/tendências , Fatores de Tempo , Disfunção Ventricular Direita/mortalidade , Disfunção Ventricular Direita/cirurgiaRESUMO
Pulmonary hypertension (PH) associated with heart failure with preserved ejection fraction (PH-HFpEF; World Health Organization Group II) secondary to left ventricular (LV) diastolic dysfunction is the most frequent cause of PH. It is an increasingly recognized clinical complication of the metabolic syndrome. To date, no effective treatment has been identified, and no genetically modifiable mouse model is available for advancing our understanding for PH-HFpEF. To develop a mouse model of PH-HFpEF, we exposed 36 mouse strains to 20 weeks of high-fat diet (HFD), followed by systematic evaluation of right ventricular (RV) and LV pressure-volume analysis. The HFD induces obesity, glucose intolerance, insulin resistance, hyperlipidemia, as well as PH, in susceptible strains. We observed that certain mouse strains, such as AKR/J, NON/shiLtJ, and WSB/EiJ, developed hemodynamic signs of PH-HFpEF. Of the strains that develop PH-HFpEF, we selected AKR/J for further model validation, as it is known to be prone to HFD-induced metabolic syndrome and had low variability in hemodynamics. HFD-treated AKR/J mice demonstrate reproducibly higher RV systolic pressure compared with mice fed with regular diet, along with increased LV end-diastolic pressure, both RV and LV hypertrophy, glucose intolerance, and elevated HbA1c levels. Time course assessments showed that HFD significantly increased body weight, RV systolic pressure, LV end-diastolic pressure, biventricular hypertrophy, and HbA1c throughout the treatment period. Moreover, we also identified and validated 129S1/SvlmJ as a resistant mouse strain to HFD-induced PH-HFpEF. These studies validate an HFD/AKR/J mouse model of PH-HFpEF, which may offer a new avenue for testing potential mechanisms and treatments for this disease.
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Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/fisiopatologia , Hipertensão Pulmonar/complicações , Hipertensão Pulmonar/fisiopatologia , Síndrome Metabólica/complicações , Síndrome Metabólica/fisiopatologia , Volume Sistólico , Animais , Pressão Sanguínea , Diástole , Dieta Hiperlipídica , Modelos Animais de Doenças , Progressão da Doença , Insuficiência Cardíaca/patologia , Hipertensão Pulmonar/patologia , Síndrome Metabólica/patologia , Camundongos , Camundongos Endogâmicos AKR , Reprodutibilidade dos Testes , SístoleRESUMO
Pulmonary hypertension (PH) is associated with features of obesity and metabolic syndrome that translate to the induction of PH by chronic high-fat diet (HFD) in some inbred mouse strains. We conducted a genome-wide association study (GWAS) to identify candidate genes associated with susceptibility to HFD-induced PH. Mice from 36 inbred and wild-derived strains were fed with regular diet or HFD for 20 weeks beginning at 6-12 weeks of age, after which right ventricular (RV) and left ventricular (LV) end-systolic pressure (ESP) and maximum pressure (MaxP) were measured by cardiac catheterization. We tested for association of RV MaxP and RV ESP and identified genomic regions enriched with nominal associations to both of these phenotypes. We excluded genomic regions if they were also associated with LV MaxP, LV ESP, or body weight. Genes within significant regions were scored based on the shortest-path betweenness centrality, a measure of network connectivity, of their human orthologs in a gene interaction network of human PH-related genes. WSB/EiJ, NON/ShiLtJ, and AKR/J mice had the largest increases in RV MaxP after high-fat feeding. Network-based scoring of GWAS candidates identified epidermal growth factor receptor (Egfr) as having the highest shortest-path betweenness centrality of GWAS candidates. Expression studies of lung homogenate showed that EGFR expression is increased in the AKR/J strain, which developed a significant increase in RV MaxP after high-fat feeding as compared with C57BL/6J, which did not. Our combined GWAS and network-based approach adds evidence for a role for Egfr in murine PH.
Assuntos
Receptores ErbB/metabolismo , Estudo de Associação Genômica Ampla , Hipertensão Pulmonar/genética , Animais , Dieta Hiperlipídica , Redes Reguladoras de Genes , Predisposição Genética para Doença , Ventrículos do Coração/fisiopatologia , Hemodinâmica , Humanos , Hipertensão Pulmonar/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos AKR , Camundongos Endogâmicos C57BLRESUMO
AIMS: Thrombospondin-1 (TSP1) is a ligand for CD47 and TSP1-/- mice are protected from pulmonary hypertension (PH). We hypothesized the TSP1-CD47 axis is upregulated in human PH and promotes pulmonary arterial vasculopathy. METHODS AND RESULTS: We analyzed the molecular signature and functional response of lung tissue and distal pulmonary arteries (PAs) from individuals with (n = 23) and without (n = 16) PH. Compared with controls, lungs and distal PAs from PH patients showed induction of TSP1-CD47 and endothelin-1/endothelin A receptor (ET-1/ETA) protein and mRNA. In control PAs, treatment with exogenous TSP1 inhibited vasodilation and potentiated vasoconstriction to ET-1. Treatment of diseased PAs from PH patients with a CD47 blocking antibody improved sensitivity to vasodilators. Hypoxic wild type (WT) mice developed PH and displayed upregulation of pulmonary TSP1, CD47, and ET-1/ETA concurrent with down regulation of the transcription factor cell homolog of the v-myc oncogene (cMyc). In contrast, PH was attenuated in hypoxic CD47-/- mice while pulmonary TSP1 and ET-1/ETA were unchanged and cMyc was overexpressed. In CD47-/- pulmonary endothelial cells cMyc was increased and ET-1 decreased. In CD47+/+ cells, forced induction of cMyc suppressed ET-1 transcript, whereas suppression of cMyc increased ET-1 signaling. Furthermore, disrupting TSP1-CD47 signaling in pulmonary smooth muscle cells abrogated ET-1-stimulated hypertrophy. Finally, a CD47 antibody given 2 weeks after monocrotaline challenge in rats upregulated pulmonary cMyc and improved aberrations in PH-associated cardiopulmonary parameters. CONCLUSIONS: In pre-clinical models of PH CD47 targets cMyc to increase ET-1 signaling. In clinical PH TSP1-CD47 is upregulated, and in both, contributes to pulmonary arterial vasculopathy and dysfunction.
Assuntos
Pressão Arterial , Antígeno CD47/metabolismo , Hipertensão Pulmonar/metabolismo , Artéria Pulmonar/metabolismo , Transdução de Sinais , Trombospondina 1/metabolismo , Adulto , Idoso , Animais , Antígeno CD47/genética , Estudos de Casos e Controles , Linhagem Celular , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Endotelina-1/metabolismo , Feminino , Predisposição Genética para Doença , Humanos , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/fisiopatologia , Hipertensão Pulmonar/prevenção & controle , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Fenótipo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Artéria Pulmonar/fisiopatologia , Interferência de RNA , Ratos , Trombospondina 1/deficiência , Trombospondina 1/genética , Transfecção , Regulação para Cima , Vasoconstrição , Vasodilatação , Adulto JovemRESUMO
BACKGROUND: Pulmonary hypertension (PH) is associated with poor outcomes, yet specific treatments only exist for a small subset of patients. The most common form of PH is that associated with left heart disease (Group 2), for which there is no approved therapy. Nitrite has shown efficacy in preclinical animal models of Group 1 and 2 PH, as well as in patients with left heart failure with preserved ejection fraction (HFpEF). We evaluated the safety and efficacy of a potentially novel inhaled formulation of nitrite in PH-HFpEF patients as compared with Group 1 and 3 PH. METHODS: Cardiopulmonary hemodynamics were recorded after acute administration of inhaled nitrite at 2 doses, 45 and 90 mg. Safety endpoints included change in systemic blood pressure and methemoglobin levels. Responses were also compared with those administered inhaled nitric oxide. RESULTS: Thirty-six patients were enrolled (10 PH-HFpEF, 20 Group 1 pulmonary arterial hypertension patients on background PH-specific therapy, and 6 Group 3 PH). Drug administration was well tolerated. Nitrite inhalation significantly lowered pulmonary, right atrial, and pulmonary capillary wedge pressures, most pronounced in patients with PH-HFpEF. There was a modest decrease in cardiac output and systemic blood pressure. Pulmonary vascular resistance decreased only in Group 3 PH patients. There was substantial increase in pulmonary artery compliance, most pronounced in patients with PH-HFpEF. CONCLUSIONS: Inhaled nitrite is safe in PH patients and may be efficacious in PH-HFpEF and Group 3 PH primarily via improvements in left and right ventricular filling pressures and pulmonary artery compliance. The lack of change in pulmonary vascular resistance likely may limit efficacy for Group 1 patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT01431313 FUNDING. This work was supported in part by the NIH grants P01HL103455 (to MAS and MTG), R01HL098032 (to MTG), and R01HL096973 (to MTG), and Mast Therapeutics, Inc.
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Insuficiência Cardíaca/tratamento farmacológico , Hipertensão Pulmonar/tratamento farmacológico , Nitrito de Sódio/administração & dosagem , Administração por Inalação , Adulto , Idoso , Feminino , Hemodinâmica , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Nitrito de Sódio/farmacologia , Volume SistólicoRESUMO
The inotropic effects of prostacyclins in chronic pulmonary arterial hypertension (PAH) are unclear and may be important in directing patient management in the acute setting. We sought to study the effects of an acute intravenous (IV) infusion of iloprost on right ventricular (RV) contractility in a rat model of chronic PAH. Rats were treated with monocrotaline, 60 mg/kg intraperitoneally, to induce PAH. Six weeks later, baseline hemodynamic assessment was performed with pressure-volume and Doppler flow measurements. In one group of animals, measurements were repeated 10-15 minutes after IV infusion of a fixed dose of iloprost (20 µg/kg). A separate group of rats underwent dose-response assessment. RV contractility and RV-pulmonary artery coupling were assessed by the end-systolic pressure-volume relationship (ESPVR) and end-systolic elastance/effective arterial elastance (Ees/Ea). RV cardiomyocytes were isolated, and intracellular cAMP (cyclic adenosine monophosphate) concentration was measured with a cAMP-specific enzyme immunoassay kit. Animals had evidence of PAH and RV hypertrophy. Right ventricle/(left ventricle + septum) weight was 0.40 ± 0.03. RV systolic pressure (RVSP) was 39.83 ± 1.62 mmHg. Administration of iloprost demonstrated an increase in the slope of the ESPVR from 0.29 ± 0.02 to 0.42 ± 0.05 (P < .05). Ees/Ea increased from 0.63 ± 0.07 to 0.82 ± 0.06 (P < .05). The RV contractility index (max dP/dt normalized for instantaneous pressure) increased from 94.11 to 114.5/s (P < .05), as did the RV ejection fraction, from 48.0% to 52.5% (P < .05). This study suggests a positive inotropic effect of iloprost on a rat model of chronic PAH.