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1.
J Cardiovasc Magn Reson ; 23(1): 136, 2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34852822

RESUMO

BACKGROUND: Data on the prognostic value of left ventricular (LV) morphological and functional parameters including LV rotation in patients with dilated cardiomyopathy (DCM) using cardiovascular magnetic resonance (CMR) are currently scarce. In this study, we assessed the prognostic value of global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) and LV torsion using CMR feature tracking (FT). METHODS: CMR was performed in 350 DCM patients and 70 healthy subjects across 5 different European CMR Centers. Myocardial strain parameters were retrospectively assessed from conventional balanced steady-state free precession cine images applying FT. A combined primary endpoint (cardiac death, heart transplantation, aborted sudden cardiac death) was defined for the assessment of clinical outcome. RESULTS: GLS, GCS, GRS and LV torsion were significantly lower in DCM patients than in healthy subjects (all p < 0.001). The primary endpoint occurred in 59 (18.7%) patients [median follow-up 4.2 (2.0-5.6) years]. In the univariate analyses all strain parameters showed a significant prognostic value (p < 0.05). In the multivariate model, LV strain parameters, particularly GLS provided an incremental prognostic value compared to established CMR parameters like LV ejection fraction and late gadolinium enhancement. A scoring model including six categorical variables of standard CMR and strain parameters differentiated further risk subgroups. CONCLUSION: LV strain assessed with CMR FT has a high prognostic value in patients with DCM, surpassing routine and dedicated functional parameters. Thus, CMR strain imaging may contribute to the improvement of risk stratification in DCM.


Assuntos
Cardiomiopatia Dilatada , Cardiomiopatia Dilatada/diagnóstico por imagem , Meios de Contraste , Gadolínio , Humanos , Imagem Cinética por Ressonância Magnética , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Volume Sistólico , Função Ventricular Esquerda
2.
J Cardiovasc Magn Reson ; 19(1): 87, 2017 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-29121956

RESUMO

BACKGROUND: To compare the prognostic value of cardiac valve plane displacement (CVPD) on various locations in cardiac light chain (AL) amyloidosis. METHODS: Consecutive patients with biopsy-proven cardiac involvement in AL amyloidosis who had undergone cardiovascular magnetic resonance (CMR) between 2005 and 2014 in our institution, were retrospectively identified and data analyzed. The primary combined endpoint was all-cause mortality or heart transplantation. Systolic CVPD were obtained from standard cine bSSFP in 2-, 3- and 4-chamber views at anterior aortic plane systolic excursion (AAPSE); anterior, anterolateral, inferolateral, inferior, inferoseptal mitral (MAPSE); and lateral tricuspid (TAPSE) annular segments. RESULTS: We identified 68 patients (58 ± 10 years; 59% male). Median follow-up period was 1.2 years (IQR, 0.3-4.1). Significant differences in CVPD between patients who reached a primary endpoint (n = 44) and transplant-free survivors were found only for AAPSE (6.1 mm (IQR, 4.6-9.4) vs. 8.8 mm (IQR, 6.9-10.4); p = 0.02) and MAPSEanterolateral (7.3 mm (IQR, 5.4-11.7) vs. 10.5 mm (IQR, 8.1-13.4); p = 0.03). AAPSE (χ2 = 15.6; p = 0.0002) provided the best predictive value for transplant-free survival compared to all other valvular plane locations. A high-risk cutoff (AAPSE ≤ 7.6 mm) was calculated by ROC analysis to predict all-cause death or heart transplantation within 6 months from index examination (AUC = 0.80; CI: 0.68 to 0.89; p < 0.0001). AAPSE added incremental prognostic power to an imaging prediction model of late gadolinium enhancement and global longitudinal strain (GLS) (∆χ2 = 5.8, p = 0.02) as well as to a clinical model including Karnofsky index and NT-proBNP (∆χ2 = 6.2, p = 0.01). CONCLUSION: In patients with cardiac involvement in AL amyloidosis, systolic CVPD obtained from standard long axis cine views appear to indicate outcome better, when obtained in the anterior aortic plane (AAPSE) and provide incremental prognostic value to LGE and strain measurements.


Assuntos
Cardiomiopatias/diagnóstico por imagem , Amiloidose de Cadeia Leve de Imunoglobulina/diagnóstico por imagem , Imageamento por Ressonância Magnética , Contração Miocárdica , Função Ventricular Esquerda , Idoso , Área Sob a Curva , Biópsia , Cardiomiopatias/mortalidade , Cardiomiopatias/fisiopatologia , Cardiomiopatias/cirurgia , Distribuição de Qui-Quadrado , Feminino , Alemanha , Transplante de Coração , Humanos , Amiloidose de Cadeia Leve de Imunoglobulina/mortalidade , Amiloidose de Cadeia Leve de Imunoglobulina/fisiopatologia , Amiloidose de Cadeia Leve de Imunoglobulina/cirurgia , Estimativa de Kaplan-Meier , Avaliação de Estado de Karnofsky , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Curva ROC , Reprodutibilidade dos Testes , Estudos Retrospectivos , Fatores de Tempo
3.
J Cardiovasc Imaging ; 31(1): 26-38, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36693342

RESUMO

BACKGROUND: Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS. METHODS: In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS. RESULTS: A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms. CONCLUSIONS: Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

4.
Front Cardiovasc Med ; 9: 990108, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36061550

RESUMO

During the worldwide ongoing immunization campaign against SARS-CoV-2, growing data on very rare but potentially harmful side effects of such vaccines arise since approval trials have not been adequately powered to detect those events. Besides the already reported vaccine-related myocarditis, which primarily occurs in young male individuals, our attention was recently drawn to a series of older male and female patients, who were referred to our institutions with isolated acute pericarditis without myocardial damage, shortly after SARS-CoV-2 vaccination. We describe a series of five adult patients presenting with chest pain, shortness of breath and isolated pericarditis with and without pericardial effusion after SARS-CoV-2 vaccination. All patients underwent echocardiography and cardiac magnetic resonance, and the corresponding findings, including late gadolinium enhancement (LGE) and T1 and T2 mapping are reported herein. To our knowledge, such cases have not been systematically reported in the current literature so far.

5.
JACC Cardiovasc Imaging ; 14(10): 1932-1944, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33865775

RESUMO

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of a fast, needle-free test for myocardial ischemia using fast Strain-ENCoded (fSENC) cardiovascular MR (CMR) after a hyperventilation/breath-hold maneuver (HVBH). BACKGROUND: Myocardial stress testing is one of the most frequent diagnostic tests performed. Recent data indicate that CMR first-pass perfusion outperforms other modalities. Its use, however, is limited by the need for both, a vasodilatory stress and the intravenous application of gadolinium. Both are associated with added cost, safety concerns, and patient inconvenience. The combination of 2 novel CMR approaches, fSENC, an ultrafast technique to visualize myocardial strain, and HVBH, a physiological vasodilator, may overcome these limitations. METHODS: Patients referred for CMR stress testing underwent an extended protocol to evaluate 3 different tests: 1) adenosine-perfusion; 2) adenosine-strain; and 3) HVBH-strain. Diagnostic accuracy was assessed using quantitative coronary angiography as reference. RESULTS: A total of 122 patients (age 66 ± 11years; 80% men) suspected of obstructive coronary artery disease were enrolled. All participants completed the protocol without significant adverse events. Adenosine-strain and HVBH-strain provided significantly better diagnostic accuracy than adenosine-perfusion, both on a patient level (adenosine-strain: sensitivity 82%, specificity 83%; HVBH-strain: sensitivity 81%, specificity 86% vs. adenosine-perfusion: sensitivity 67%, specificity 92%; p < 0.05) and territory level (adenosine-strain: sensitivity 67%, specificity 93%; HVBH-strain: sensitivity 63%, specificity 95% vs. adenosine-perfusion: sensitivity 49%, specificity 96%; p < 0.05). However, these differences in diagnostic accuracy disappear by excluding patients with history of coronary artery bypass graft or previous myocardial infarction. The response of longitudinal strain differs significantly between ischemic and nonischemic segments to adenosine (ΔLSischemic = 0.6 ± 5.4%, ΔLSnonischemic = -0.9 ± 2.7%; p < 0.05) and HVBH (ΔLSischemic = 1.3% ± 3.8%, ΔLSnonischemic = -0.3 ± 1.8%; p = 0.002). Test duration of HVBH-strain (t = 64 ± 2 s) was significantly shorter compared with adenosine-strain (t = 184 ± 59 s; p < 0.0001) and adenosine-perfusion (t = adenosine-perfusion: 172 ± 59 s; p < 0.0001). CONCLUSIONS: HVBH-strain has a high diagnostic accuracy in detecting significant coronary artery stenosis. It is not only significantly faster than any other method but also neither requires contrast agents nor pharmacological stressors.


Assuntos
Doença da Artéria Coronariana , Isquemia Miocárdica , Imagem de Perfusão do Miocárdio , Idoso , Angiografia Coronária , Circulação Coronária , Feminino , Humanos , Hiperventilação , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/diagnóstico por imagem , Valor Preditivo dos Testes , Vasodilatadores
6.
Front Cardiovasc Med ; 8: 755759, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34912862

RESUMO

Background: Cardiac magnetic resonance (CMR) pharmacological stress-testing is a well-established technique for detecting myocardial ischemia. Although stressors and contrast agents seem relatively safe, contraindications and side effects must be considered. Substantial costs are further limiting its applicability. Dynamic handgrip exercise (DHE) may have the potential to address these shortcomings as a physiological stressor. We therefore evaluated the feasibility and physiologic stress response of DHE in relation to pharmacological dobutamine-stimulation within the context of CMR examinations. Methods: Two groups were prospectively enrolled: (I) volunteers without relevant disease and (II) patients with known CAD referred for stress-testing. A both-handed, metronome-guided DHE was performed over 2 min continuously with 80 contractions/minute by all participants, whereas dobutamine stress-testing was only performed in group (II). Short axis strain by fast-Strain-ENCoded imaging was acquired at rest, immediately after DHE and during dobutamine infusion. Results: Eighty middle-aged individuals (age 56 ± 17 years, 48 men) were enrolled. DHE triggered significant positive chronotropic (HRrest: 68 ± 10 bpm, HRDHE: 91 ± 13 bpm, p < 0.001) and inotropic stress response (GLSrest: -19.4 ± 1.9%, GLSDHE: -20.6 ± 2.1%, p < 0.001). Exercise-induced increase of longitudinal strain was present in healthy volunteers and patients with CAD to the same extent, but in general more pronounced in the midventricular and apical layers (p < 0.01). DHE was aborted by a minor portion (7%) due to peripheral fatigue. The inotropic effect of DHE appears to be non-inferior to intermediate dobutamine-stimulation (GLSDHE= -19.5 ± 2.3%, GLSDob= -19.1 ± 3.1%, p = n.s.), whereas its chronotropic effect was superior (HRDHE= 89 ± 14 bpm, HRDob= 78 ± 15 bpm, p < 0.001). Conclusions: DHE causes positive ino- and chronotropic effects superior to intermediate dobutamine-stimulation, suggesting a relevant increase of myocardial oxygen demand. DHE appears to be safe and timesaving with broad applicability. The data encourages further studies to determine its potential to detect obstructive CAD.

7.
Int J Cardiovasc Imaging ; 33(5): 721-729, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28110433

RESUMO

Cardiac valve plane displacement (CVPD) reflects longitudinal LV function. The purpose of the present study was to determine regional heterogeneity of CVPD in healthy adults to provide normal values by cardiac magnetic resonance (CMR). We measured the anterior aortic plane systolic excursion (AAPSE); the anterior, anterolateral, inferolateral, inferior, and inferoseptal mitral annular plane systolic excursion (MAPSE); and the lateral tricuspid annulus plane systolic excursion (TAPSE). Systolic excursion was measured as the distance from peak end-diastolic to peak end-sysstolic annular position (peak-to-peak) in cine images acquired in 2-, 3- and 4-chamber views. Echocardiographic measurements of CVPD were performed in M-Mode as previously described. We retrospectively analyzed 209 healthy Caucasians (57% men), who participated in the Heidelberg normal cohort between March 2009 and September 2014. The analysis was possible in all participants. Mean values were: AAPSE = 14 ± 3 mm (8-20); MAPSEanterior = 14 ± 3 mm (8-20); MAPSEanterolateral = 16 ± 3 mm (10-22); MAPSEinferolateral = 16 ± 3 mm (10-22); MAPSEinferior = 17 ± 3 mm (11-23); MAPSEinferoseptal = 13 ± 3 mm (7-19) and TAPSE = 26 ± 4 mm (18-34) respectively. MAPSE was significantly elevated in lateral compared to septal regions (p = 0.0001). Sex-differences for CVPD were not found. Age-dependency of CVPD revealed distinct regional differences. AAPSE decreased the most with age (B=-0.48; p = 0.0001), whereas MAPSEinferior was the least age-dependent site (B=-0.17; p = 0.01). AAPSE revealed favorable intra-/interobserver reproducibility and interstudy agreement. Intermethod-comparison of CMR and M-Mode echocardiography showed good agreement between both measurements of CVPD. Age-stratified normal values of regional CVPD are provided. AAPSE revealed the most pronounced age-related decrease and provided favorable reproducibility compared to other regions of cardiac valve plane.


Assuntos
Valva Aórtica/diagnóstico por imagem , Imagem Cinética por Ressonância Magnética , Valva Mitral/diagnóstico por imagem , Valva Tricúspide/diagnóstico por imagem , Função Ventricular Esquerda , Adulto , Distribuição por Idade , Valva Aórtica/fisiologia , Ecocardiografia , Feminino , Alemanha , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/fisiologia , Variações Dependentes do Observador , Valor Preditivo dos Testes , Valores de Referência , Reprodutibilidade dos Testes , Estudos Retrospectivos , Valva Tricúspide/fisiologia , População Branca
8.
Clin Res Cardiol ; 106(7): 485-492, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28168514

RESUMO

BACKGROUND: The usage of coronary CT angiography (CTA) is appropriate in patients with acute or chronic chest pain; however the diagnostic accuracy may be challenged with increased Agatston score (AS), increased heart rate, arrhythmia and severe obesity. Thus, we aim to determine the potential of the recently introduced third-generation dual-source CT (DSCT) for CTA in a 'real-life' clinical setting. METHODS: Two hundred and sixty-eight consecutive patients (age: 67 ± 10 years; BMI: 27 ± 5 kg/m²; 61% male) undergoing clinically indicated CTA with DSCT were included in the retrospective single-center analysis. A contrast-enhanced volume dataset was acquired in sequential (SSM) (n = 151) or helical scan mode (HSM) (n = 117). Coronary segments were classified in diagnostic or non-diagnostic image quality. A subset underwent invasive angiography to determine the diagnostic accuracy of CTA. RESULTS: SSM (96.8 ± 6%) and HSM (97.5 ± 8%) provided no significant differences in the overall diagnostic image quality. However, AS had significant influence on diagnostic image quality exclusively in SSM (B = 0.003; p = 0.0001), but not in HSM. Diagnostic image quality significantly decreased in SSM in patients with AS ≥2,000 (p = 0.03). SSM (sensitivity: 93.9%; specificity: 96.7%; PPV: 88.6%; NPV: 98.3%) and HSM (sensitivity: 97.4%; specificity: 94.3%; PPV: 86.0%; NPV: 99.0%) provided comparable diagnostic accuracy (p = n.s.). SSM yielded significantly lower radiation doses as compared to HSM (2.1 ± 2.0 vs. 5.1 ± 3.3 mSv; p = 0.0001) in age and BMI-matched cohorts. CONCLUSION: SSM in third-generation DSCT enables significant dose savings and provides robust diagnostic image quality in patients with AS ≤2000 independent of heart rate, heart rhythm or obesity.


Assuntos
Angiografia por Tomografia Computadorizada/métodos , Angiografia Coronária/métodos , Estenose Coronária/diagnóstico , Vasos Coronários/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/métodos , Idoso , Feminino , Seguimentos , Humanos , Masculino , Doses de Radiação , Reprodutibilidade dos Testes , Estudos Retrospectivos
9.
J Am Soc Echocardiogr ; 29(12): 1188-1196, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-28042785

RESUMO

BACKGROUND: Anterior aortic plane systolic excursion (AAPSE) was evaluated in the present pilot study as a novel echocardiographic indicator of transplant-free survival in patients with systemic light-chain amyloidosis. METHODS: Eighty-nine patients with light-chain amyloidosis were included in the post-hoc analysis. A subgroup of 54 patients with biopsy-proven cardiac amyloid infiltration were compared with 41 healthy individuals to evaluate the discriminative ability of echocardiographic findings. AAPSE is defined as the systolic excursion of the anterior aortic margin. To quantify AAPSE, the M-mode cursor was placed on the aortic valve plane in parasternal long-axis view at end-diastole. Index echocardiography had been performed before chemotherapy. Median follow-up duration was 2.4 years. The primary combined end point was heart transplantation or overall death. RESULTS: Mean AAPSE was 14 ± 2 mm in healthy individuals (mean age=57 ± 10 years; 56% men; BMI=25 ± 4 kg/m2). AAPSE < 11 mm separated patients from age-, gender-, and BMI-matched control subjects with 93% sensitivity and 97% specificity. Median transplant-free survival of patients with AAPSE < 5 mm was 0.7 versus 4.8 years (P = .0001). AAPSE was an independent indicator of transplant-free survival in multivariate Cox regression (echocardiographic model: hazard ratio=0.72 [P = .03]; biomarker model: hazard ratio=0.62 [P = .0001]). Sequential regression analysis suggested incremental power of AAPSE as a marker of transplant-free survival. An ejection fraction-based model with an overall χ2 value of 22.8 was improved by the addition of log NT-proBNP (χ2 = 32.6, P < .005), troponin-T (χ2 = 39.6, P < .01), and AAPSE (χ2 = 54.0, P < .0001). CONCLUSIONS: AAPSE is suggested as an indicator of transplant-free survival in patients with systemic light-chain amyloidosis. AAPSE provided significant incremental value to established staging models.


Assuntos
Aorta/diagnóstico por imagem , Cardiomiopatia Restritiva/diagnóstico por imagem , Cardiomiopatia Restritiva/mortalidade , Ecocardiografia/métodos , Amiloidose de Cadeia Leve de Imunoglobulina/diagnóstico por imagem , Amiloidose de Cadeia Leve de Imunoglobulina/mortalidade , Cardiomiopatia Restritiva/cirurgia , Intervalo Livre de Doença , Ecocardiografia/estatística & dados numéricos , Feminino , Alemanha/epidemiologia , Transplante de Coração/mortalidade , Transplante de Coração/estatística & dados numéricos , Humanos , Amiloidose de Cadeia Leve de Imunoglobulina/cirurgia , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Taxa de Sobrevida , Resultado do Tratamento
10.
PLoS One ; 11(1): e0146988, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26811901

RESUMO

AIMS: Inhibition of ß-adrenergic signalling plays a key role in treatment of heart failure. Gsα is essential for ß-adrenergic signal transduction. In order to reduce side-effects of beta-adrenergic inhibition diminishing ß-adrenergic signalling in the heart at the level of Gsα is a promising option. METHODS AND RESULTS: We analyzed the influence of Gsα on regulation of myocardial function and development of cardiac hypertrophy, using a transgenic mouse model (C57BL6/J mice) overexpressing a dominant negative Gsα-mutant under control of the α-MHC-promotor. Cardiac phenotype was characterized in vivo and in vitro and under acute and chronic ß-adrenergic stimulation. At rest, Gsα-DN-mice showed bradycardia (602 ± 13 vs. 660 ± 17 bpm, p<0.05) and decreased dp/dtmax (5037 ± 546- vs. 6835 ± 505 mmHg/s, p = 0.02). No significant differences were found regarding ejection fraction, heart weight and cardiomyocyte size. ß-blockade by propranolol revealed no baseline differences of hemodynamic parameters between wildtype and Gsα-DN-mice. Acute adrenergic stimulation resulted in decreased ß-adrenergic responsiveness in Gsα-DN-mice. Under chronic adrenergic stimulation, wildtype mice developed myocardial hypertrophy associated with increase of LV/BW-ratio by 23% (4.4 ± 0.2 vs. 3.5 ± 0.1 mg/g, p<0.01) and cardiac myocyte size by 24% (14927 ± 442 px vs. 12013 ± 583 px, p<0.001). In contrast, both parameters were unchanged in Gsα-DN-mice after chronic isoproterenol stimulation. CONCLUSION: Overexpression of a dominant negative mutant of Gsα leads to decreased ß-adrenergic responsiveness and is protective against isoproterenol-induced hypertrophy. Thus, Gsα-DN-mice provide novel insights into ß-adrenergic signal transduction and its modulation in myocardial overload and failure.


Assuntos
Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Miocárdio/metabolismo , Agonistas Adrenérgicos beta , Animais , Cardiomegalia/induzido quimicamente , Cardiomegalia/metabolismo , Tamanho Celular , AMP Cíclico/metabolismo , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Expressão Gênica , Frequência Cardíaca , Isoproterenol/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Miócitos Cardíacos/fisiologia , Transdução de Sinais , Volume Sistólico , Função Ventricular Esquerda , Pressão Ventricular
11.
PLoS One ; 8(9): e70848, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24023715

RESUMO

BACKGROUND: A prerequisite of hypertrophic response of the myocardium is an increase in protein synthesis. A central regulator of translation initiation is Eukaryotic initiation factor 2B (eIF2B). Here we assessed the hypothesis that regulation of protein synthesis via eIF2Bε is essential to cardiac hypertrophic response in vivo. METHODS: Two transgenic mouse lines were generated with cardiac restricted overexpression of eIF2Bε or its mutant eIF2Bε-eIFS(535)A, which cannot be inactivated by phosphorylation through GSK-3ß. RESULTS: (1) Under baseline conditions eIF2Bε transgenic mice showed no difference in cardiac phenotype compared to wild type, whereas in the mutant eIF2Bε-S(535)A an increase in LV/tibia length (7.5 ± 0.4 mg/mm vs. 6.2 ± 0.2 mg/mm, p<0.001) and cardiomyocyte cross sectional area (13004 ± 570 vs. 10843 ± 347 RU, p<0.01) was observed. (2) Cardiac overexpression of eIF2Bε did not change the response of the heart to pathologic stress induced by chronic isoproterenol treatment. (3) Cardiac overexpression of the eIF2Bε transgene was followed by overexpression of DYRK2 which is known to prime the inhibitory action of GSK-3ß on eIF2Bε, while DYRK1A and GSK-3ß itself were not increased. (4) In C57BL/6 mice after 48 h of isoproterenol-stimulation or aortic banding, eIF2Bε was increased and DYRK2 was concomitantly decreased. (5) In line with these in vivo findings, siRNA knockdown of DYRK2 in cultured cardiomyocytes resulted in decreased levels of p(S535)- eIF2Bε, (6) whereas adenoviral induced overexpression of DYRK2 was accompanied by clearly increased phosphorylation of eIF2Bε, indicating a coordinated response pattern (7) Adenoviral induced overexpression of DYRK2 leads to significantly reduced cardiomyocyte size and diminishes hypertrophic response to adrenergic stimulation. CONCLUSIONS: The interaction of GSK-3ß and its priming kinase DYRK2 regulate the activity of eIF2Bε in cardiac myocytes. DYRK2 is a novel negative regulator of cardiomyocyte growth. DYRK2 could serve as a therapeutic option to regulate myocardial growth.


Assuntos
Fator de Iniciação 2B em Eucariotos/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Animais , Células Cultivadas , Ecocardiografia , Fator de Iniciação 2B em Eucariotos/genética , Quinase 3 da Glicogênio Sintase/genética , Glicogênio Sintase Quinase 3 beta , Hipertrofia Ventricular Esquerda/genética , Hipertrofia Ventricular Esquerda/metabolismo , Imunoprecipitação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Quinases Dyrk
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