RESUMO
The anticancer efficacy of anthracyclines is limited by congestive heart failure. Clinically established markers of early onset of cardiotoxicity following anthracycline treatment and preventive measures are missing. Although statins are reported to alleviate anthracycline-induced cardiotoxicity in vivo, the molecular mechanisms involved remain elusive. In vitro data point to Rac1 as major target of the cytoprotective statin effects. Here we investigated whether specific inhibition of Rac1 by NSC23766 is as effective as lovastatin in preventing subacute cardiotoxicity following doxorubicin treatment. C57BL/6 mice were treated over 3 weeks with multiple low doses of doxorubicin (6 × 3 mg/kg BW, i.p.) and the level of DNA damage, apoptosis and regenerative proliferation as well as pro-inflammatory, pro-fibrotic and oxidative stress responses were investigated. Moreover, heart function was monitored by echocardiography. Doxorubicin induced subacute cardiotoxicity which was reflected on the level of residual DNA damage, frequency of apoptotic and mitotic cells as well as elevated mRNA expression of markers of heart failure, remodeling and mitochondrial biogenesis. These molecular markers of cardiotoxicity were mitigated to a similar extent by co-treatment with either lovastatin (10 mg/kg BW, p.o.) or NSC23766 (5 mg/kg BW, i.p.) three times a week. Moreover, doxorubicin caused diastolic dysfunction as reflected by increased E-wave acceleration time (EAT), which again was prevented by pharmacological inhibition of Rac1. Inhibition of Rac1 signaling is of major relevance for the cardioprotective effects of lovastatin in the context of anthracycline-induced cardiotoxicity. Moreover, EAT is a useful marker of subacute cardiotoxicity caused by persisting harmful effects of doxorubicin.
Assuntos
Cardiotoxicidade/etiologia , Doxorrubicina/efeitos adversos , Lovastatina/farmacologia , Neuropeptídeos/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Aminoquinolinas/farmacologia , Animais , Antibióticos Antineoplásicos/efeitos adversos , Cardiotônicos/farmacologia , Cardiotoxicidade/fisiopatologia , Cardiotoxicidade/prevenção & controle , Dano ao DNA/efeitos dos fármacos , Diástole/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Doxorrubicina/administração & dosagem , Eletrocardiografia , Masculino , Camundongos Endogâmicos C57BL , Neuropeptídeos/antagonistas & inibidores , Pirimidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Testes de Toxicidade Subaguda/métodos , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidoresRESUMO
PURPOSE: Development of AV-block is a frequent complication associated with transcatheter aortic valve implantation (TAVI). To date little is known about the predictive value of the HV-interval prior to TAVI with respect to the risk of AV-block development. METHODS AND RESULTS: HV-interval was determined in 25 consecutive elderly patients with severe aortic valve stenosis (AS) before and immediately after TAVI. All patients subsequently underwent TAVI and 8 of these 25 patients (32%) developed complete AV-block during the TAVI procedure requiring permanent pacemaker implantation. Six of these 8 patients (75%) had marked HV prolongation (>54 ms). Pre-procedural HV-interval was significantly prolonged in the subgroup developing complete AV-block (62.1 ms±13.0 vs 49.2 ms±12.9; P=0.029). Prolongation of the HV-interval above 54 ms was associated with a higher rate of complete AV-block (sensitivity 75.0%, specificity 77.8%, P=0.01). CONCLUSIONS: HV-interval was prolonged in approximately one third of our elderly patients with aortic valve stenosis and associated with a high rate of complete AV-block following TAVI. HV-interval is easily obtained during TAVI screening procedures, thus facilitating identification of patients at risk for complete AV-block due to TAVI and consequently enabling bespoke risk management.
Assuntos
Estenose da Valva Aórtica/terapia , Valva Aórtica/fisiopatologia , Arritmias Cardíacas/fisiopatologia , Bloqueio Atrioventricular/etiologia , Cateterismo Cardíaco/efeitos adversos , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Implante de Prótese de Valva Cardíaca/efeitos adversos , Idoso , Estenose da Valva Aórtica/complicações , Estenose da Valva Aórtica/diagnóstico , Estenose da Valva Aórtica/fisiopatologia , Arritmias Cardíacas/complicações , Arritmias Cardíacas/diagnóstico , Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/fisiopatologia , Bloqueio Atrioventricular/terapia , Cateterismo Cardíaco/instrumentação , Cateterismo Cardíaco/métodos , Estimulação Cardíaca Artificial , Feminino , Próteses Valvulares Cardíacas , Implante de Prótese de Valva Cardíaca/instrumentação , Implante de Prótese de Valva Cardíaca/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Valor Preditivo dos Testes , Desenho de Prótese , Medição de Risco , Fatores de Risco , Resultado do TratamentoRESUMO
Nitric oxide (NO) derived from endothelial NO synthase (NOS3) plays a central role in myocardial ischemia/reperfusion (I/R)-injury. Subsets of circulating blood cells, including red blood cells (RBCs), carry a NOS3 and contribute to blood pressure regulation and RBC nitrite/nitrate formation. We hypothesized that the circulating blood born NOS3 also modulates the severity of myocardial infarction in disease models. We cross-transplanted bone marrow in wild-type and NOS3(-/-) mice with wild-type mice, producing chimeras expressing NOS3 only in vascular endothelium (BC-/EC+) or in both blood cells and vascular endothelium (BC+/EC+). After 60-min closed-chest coronary occlusion followed by 24 h reperfusion, cardiac function, infarct size (IS), NOx levels, RBCs NO formation, RBC deformability, and vascular reactivity were assessed. At baseline, BC-/EC+ chimera had lower nitrite levels in blood plasma (BC-/EC+: 2.13 ± 0.27 µM vs. BC+/EC+ 3.17 ± 0.29 µM; *p < 0.05), reduced DAF FM associated fluorescence within RBCs (BC-/EC+: 538.4 ± 12.8 mean fluorescence intensity (MFI) vs. BC+/EC+: 619.6 ± 6.9 MFI; ***p < 0.001) and impaired erythrocyte deformability (BC-/EC+: 0.33 ± 0.01 elongation index (EI) vs. BC+/EC+: 0.36 ± 0.06 EI; *p < 0.05), while vascular reactivity remained unaffected. Area at risk did not differ, but infarct size was higher in BC-/EC+ (BC-/EC+: 26 ± 3 %; BC+/EC+: 14 ± 2 %; **p < 0.01), resulting in decreased ejection fraction (BC-/EC+ 46 ± 2 % vs. BC+/EC+: 52 ± 2 %; *p < 0.05) and increased end-systolic volume. Application of the NOS inhibitor S-ethylisothiourea hydrobromide was associated with larger infarct size in BC+/EC+, whereas infarct size in BC-/EC+ mice remained unaffected. Reduced infarct size, preserved cardiac function, NO levels in RBC and RBC deformability suggest a modulating role of circulating NOS3 in an acute model of myocardial I/R in chimeric mice.
Assuntos
Infarto do Miocárdio/sangue , Óxido Nítrico Sintase Tipo III/sangue , Disfunção Ventricular Esquerda/sangue , Animais , Western Blotting , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/sangue , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Óxido Nítrico/sangue , Quimeras de Transplante , Disfunção Ventricular Esquerda/patologia , Disfunção Ventricular Esquerda/fisiopatologiaRESUMO
Endothelial nitric oxide synthase (NOS)3-derived nitric oxide (NO) modulates inotropic response and diastolic interval for optimal cardiac performance under non-inflammatory conditions. In sepsis, excessive NO production plays a key role in severe hypotension and myocardial dysfunction. We aimed to determine the role of NOS3 on myocardial performance, NO production, and time course of sepsis development. NOS3(-/-) and C57BL/6 wildtype mice were rendered septic by cecum ligation and puncture (CLP). Cardiac function was analyzed by serial echocardiography, in vivo pressure and isolated heart measurements. Cardiac output (CO) increased to 160 % of baseline at 10 h after sepsis induction followed by a decline to 63 % of baseline after 18 h in wildtype mice. CO was unaltered in septic NOS3(-/-) mice. Despite the hyperdynamic state, cardiac function and mean arterial pressure were impaired in septic wildtype as early as 6 h post CLP. At 12 h, cardiac function in septic wildtype was refractory to catecholamines in vivo and respective isolated hearts showed impaired pressure development and limited coronary flow reserve. Hemodynamics remained stable in NOS3(-/-) mice leading to significant survival benefit. Unselective NOS inhibition in septic NOS3(-/-) mice diminished this survival benefit. Plasma NO( x )- and local myocardial NO( x )- and NO levels (via NO spin trapping) demonstrated enhanced NO( x )- and bioactive NO levels in septic wildtype as compared to NOS3(-/-) mice. Significant contribution by inducible NOS (NOS2) during this early phase of sepsis was excluded. Our data suggest that NOS3 relevantly contributes to bioactive NO pool in developing sepsis resulting in impaired cardiac contractility.
Assuntos
Cardiomiopatias/enzimologia , Modelos Animais de Doenças , Hemodinâmica/fisiologia , Óxido Nítrico Sintase Tipo III/fisiologia , Sepse/enzimologia , Animais , Pressão Arterial/fisiologia , Débito Cardíaco/fisiologia , Cardiomiopatias/fisiopatologia , Circulação Coronária/fisiologia , Ecocardiografia , Técnica Indireta de Fluorescência para Anticorpo , Testes de Função Cardíaca , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nitratos/metabolismo , Óxido Nítrico/sangue , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Sepse/fisiopatologiaRESUMO
Cardiotoxicity is the dose limiting adverse effect of anthracycline-based anticancer therapy. Inhibitor studies point to Rac1 as therapeutic target to prevent anthracycline-induced cardiotoxicity. Yet, supporting genetic evidence is still missing and the pathophysiological relevance of different cardiac cell types is unclear. Here, we employed a tamoxifen-inducible cardiomyocyte-specific rac1 knock-out mouse model (Rac1flox/flox/MHC-MerCreMer) to investigate the impact of Rac1 expression in cardiomyocytes on cardiac injury following doxorubicin treatment. Distinctive stress responses resulting from doxorubicin treatment were observed, including upregulation of systemic markers of inflammation (IL-6, IL-1α, MCP-1), cardiac damage (ANP, BNP), DNA damage (i.e. DNA double-strand breaks (DSB)), DNA damage response (DDR) and cell death. Measuring the acute doxorubicin response, the serum level of MCP-1 was elevated, cardiac mRNA expression of Hsp70 was reduced and cardiac DDR was specifically enhanced in Rac1 deficient mice. The frequency of apoptotic heart cells remained unaffected by Rac1. Employing a subactue model, the number of doxorubicin-induced DSB was significantly reduced if Rac1 is absent. Yet, the doxorubicin-triggered increase in serum ANP and BNP levels remained unaffected by Rac1. Overall, knock-out of rac1 in cardiomyocytes confers partial protection against doxorubicin-induced cardiac injury. Hence, the data provide first genetic evidence supporting the view that pharmacological targeting of Rac1 is useful to widen the therapeutic window of anthracycline-based anticancer therapy by alleviating acute/subacute cardiomyocyte damage. Furthermore, considering published data obtained from the use of pharmacological Rac1 inhibitors, the results of our study indicate that Rac1-regulated functions of cardiac cell types others than cardiomyocytes additionally influence the adverse outcomes of anthracycline treatment on the heart.
Assuntos
Antraciclinas/toxicidade , Cardiopatias/induzido quimicamente , Cardiopatias/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Neuropeptídeos/biossíntese , Proteínas rac1 de Ligação ao GTP/biossíntese , Animais , Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neuropeptídeos/genética , Proteínas rac1 de Ligação ao GTP/genéticaRESUMO
PURPOSE: Nitric oxide (NO) is constitutively produced and released from the endothelium and several blood cell types by the isoform 3 of the NO synthase (NOS3). We have shown that NO protects against myocardial ischemia/reperfusion (I/R) injury and that depletion of circulating NOS3 increases within 24 h of ischemia/reperfusion the size of myocardial infarction (MI) in chimeric mice devoid of circulating NOS3. In the current study we hypothesized that circulating NOS3 also affects remodeling of the left ventricle following reperfused MI. METHODS: To analyze the role of circulating NOS3 we transplanted bone marrow of NOS3-/- and wild type (WT) mice into WT mice, producing chimerae expressing NOS3 only in vascular endothelium (BC-/EC+) or in both, blood cells and vascular endothelium (BC+/EC+). Both groups underwent 60 min of coronary occlusion in a closed-chest model of reperfused MI. During the 3 weeks post MI, structural and functional LV remodeling was serially assessed (24 h, 4 d, 1 w, 2 w and 3 w) by echocardiography. At 72 hours post MI, gene expression of several extracellular matrix (ECM) modifying molecules was determined by quantitative RT-PCR analysis. At 3 weeks post MI, hemodynamics were obtained by pressure catheter, scar size and collagen content were quantified post mortem by Gomori's One-step trichrome staining. RESULTS: Three weeks post MI, LV end-systolic (53.2±5.9 µl; ***p≤0.001; n = 5) and end-diastolic volumes (82.7±5.6 µl; *p<0.05; n = 5) were significantly increased in BC-/EC+, along with decreased LV developed pressure (67.5±1.8 mm Hg; n = 18; ***p≤0.001) and increased scar size/left ventricle (19.5±1.5%; n = 13; **p≤0.01) compared to BC+/EC+ (ESV: 35.6±2.2 µl; EDV: 69.1±2.6 µl n = 8; LVDP: 83.2±3.2 mm Hg; n = 24; scar size/LV13.8±0.7%; n = 16). Myocardial scar of BC-/EC+ was characterized by increased total collagen content (20.2±0.8%; n = 13; ***p≤0.001) compared to BC+/EC+ (15.9±0.5; n = 16), and increased collagen type I and III subtypes. CONCLUSION: Circulating NOS3 ameliorates maladaptive left ventricular remodeling following reperfused myocardial infarction.