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2.
Internist (Berl) ; 58(10): 1114-1123, 2017 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-28835975

RESUMO

Baroreceptor activation therapy (BAT) has been available for several years for treatment of therapy-refractory hypertension (trHTN). This procedure is currently being carried out in a limited number of centers in Germany, also with the aim of offering a high level of expertise through sufficient experience; however, a growing number of patients who are treated with BAT experience problems that treating physicians are confronted with in routine medical practice. In order to address these problems, a consensus conference was held with experts in the field of trHTN in November 2016, which summarizes the current evidence and experience as well as the problem areas in handling BAT patients.


Assuntos
Barorreflexo/fisiologia , Vasoespasmo Coronário/fisiopatologia , Vasoespasmo Coronário/terapia , Terapia por Estimulação Elétrica/métodos , Hipertensão/fisiopatologia , Hipertensão/terapia , Pressão Sanguínea/fisiologia , Seio Carotídeo/fisiopatologia , Terapia por Estimulação Elétrica/instrumentação , Eletrodos Implantados , Desenho de Equipamento , Frequência Cardíaca/fisiologia , Sistema Nervoso Parassimpático/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia
3.
Internist (Berl) ; 58(1): 90-99, 2017 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-28058458

RESUMO

Atrial fibrillation and venous thromboembolisms are frequent cardiovascular diseases. Until a few years ago only vitamin K antagonists (VKA) were available for oral anticoagulation as primary and secondary prevention of thrombembolic events. Currently, the non-vitamin K dependent new oral anticoagulants (NOAC) dabigatran, rivaroxaban, apixaban and edoxaban are approved for use. The approval studies, meta-analyses and data from registries provide evidence for the superiority of NOAC vs. VKA with respect to reduction of thrombembolisms and reduced bleeding complications; therefore, in the 2016 European Society of Cardiology (ESC) guidelines the use of NOAC is recommended as first line therapy for anticoagulation in atrial fibrillation (recommendation grade I/evidence level A). In patients with mechanical heart valve replacement and severe renal dysfunction VKA are still clearly indicated. This also holds true for prophylaxis of secondary thromboembolic events in tumor patients. Thus, even today therapy with VKA must not be regarded as medical malpractice, especially when a good adjustment of the international normalized ratio can be achieved; however, for many patients NOAC represent a very good alternative and lead to at least equal results with less effort for the prescribing physician and the patient.


Assuntos
Anticoagulantes/administração & dosagem , Anticoagulantes/normas , Guias de Prática Clínica como Assunto , Tromboembolia/tratamento farmacológico , Tromboembolia/prevenção & controle , Vitamina K/antagonistas & inibidores , Administração Oral , Anticoagulantes/efeitos adversos , Cardiologia/normas , Europa (Continente) , Medicina Baseada em Evidências , Hemorragia/etiologia , Hemorragia/prevenção & controle , Humanos , Resultado do Tratamento
6.
Herz ; 38(6): 604-9, 2013 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-23880947

RESUMO

Sleep apnea can influence cardiac function, by which the development of heart failure is facilitated. Vice versa, chronic heart failure increases the risk for sleep apnea. Consequently, in patients with symptomatic chronic heart failure, sleep apnea is a frequent comorbidity occuring in up to 75% of cases. More than half of those suffer from central sleep apnea, whereas in the general population, obstructive sleep apnea is far more frequent. Both, the obstructive and the central sleep apnea lead to oxygen desaturations during the night which are followed by increases in serum catecholamines. Possibly, this is the main mechanism why the prognosis of patients with symptomatic heart failure and sleep apnea is much worse than that of patients without sleep apnea. Therefore, a screening of all heart failure patients for sleep apnea is mandatory. Currently, large studies are underway which investigate whether the treatment of sleep apnea, esp. central sleep apnea, will beneficially influence the clinical course of heart failure (SERVE-HF, ADVENT-HF). A new therapeutic approach for central sleep apnea is the phrenic nerve stimulation.


Assuntos
Depressão/diagnóstico , Depressão/epidemiologia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/epidemiologia , Programas de Rastreamento/estatística & dados numéricos , Comorbidade , Depressão/terapia , Medicina Baseada em Evidências , Insuficiência Cardíaca/terapia , Humanos , Prevalência , Fatores de Risco
8.
Gene Ther ; 19(6): 637-41, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22418064

RESUMO

Cardiovascular disease remains a leading cause of hospitalization and mortality worldwide. Conventional heart failure treatment is making steady and substantial progress to reduce the burden of disease. Nevertheless novel therapies and especially cardiac gene therapy have been emerging in the past and successfully made their way into first clinical trials. Gene therapy was initially a visionary treatment strategy for inherited, monogenetic diseases but has now developed to have potential for polygenic diseases as atherosclerosis, arrhythmias and heart failure. These novel therapeutic strategies require testing in clinically relevant animal models to transition from 'bench to bedside'. One of the major hurdles for effective cardiovascular gene therapy is the delivery of the viral vectors to the heart. In this review we present the currently available vector-mediated cardiac gene delivery methods in vivo considering the specific merits and deficiencies.


Assuntos
Técnicas de Transferência de Genes , Terapia Genética/métodos , Vetores Genéticos , Administração Cutânea , Doenças Cardiovasculares/terapia , Humanos , Injeções , Miocárdio , Pericárdio
9.
Gene Ther ; 18(10): 979-85, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21512506

RESUMO

Intrapericardial drug delivery is a promising procedure, with the ability to localize therapeutics with the heart. Gelfoam particles are nontoxic, inexpensive, nonimmunogenic and biodegradable compounds that can be used to deliver therapeutic agents. We developed a new percutaneous approach method for intrapericardial injection, puncturing the pericardial sac safely under fluoroscopy and intravascular ultrasound (IVUS) guidance. In a porcine model of myocardial infarction (MI), we deployed gelfoam particles carrying either (a) autologous mesenchymal stem cells (MSCs) or (b) an adenovirus encoding enhanced green fluorescent protein (eGFP) 48 h post-MI. The presence of MSCs and viral infection at the infarct zone was confirmed by immunoflourescence and PCR. Puncture was performed successfully in 16 animals. Using IVUS, we successfully determined the size of the pericardial space before the puncture, and safely accessed that space in setting of pericardial effusion and also adhesions induced by the MI. Intrapericardial injection of gelfoam was safe and reliable. Presence of the MSCs and eGFP expression from adenovirus in the myocardium were confirmed after delivery. Our novel percutaneous approach to deliver (stem-) cells or adenovirus was safe and efficient in this pre-clinical model. IVUS-guided delivery is a minimally invasive procedure that seems to be a promising new strategy to deliver therapeutic agents locally to the heart.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Esponja de Gelatina Absorvível/administração & dosagem , Vetores Genéticos/administração & dosagem , Transplante de Células-Tronco Mesenquimais/métodos , Infarto do Miocárdio/tratamento farmacológico , Pericárdio/diagnóstico por imagem , Adenoviridae , Administração Cutânea , Animais , Primers do DNA/genética , Imunofluorescência , Fluoroscopia , Proteínas de Fluorescência Verde/metabolismo , Imuno-Histoquímica , Reação em Cadeia da Polimerase , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Suínos , Ultrassonografia de Intervenção
10.
Dtsch Med Wochenschr ; 136(7): 315-9, 2011 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-21302206

RESUMO

Sudden loss of consciousness can be caused by syncope or epileptic seizure, which therefore requires a diagnostic work-up including cardiological and neurological examinations. Thus, in clinical practice cooperation of these two medical specialties is common and of high relevance. Seizures may lead to cardiac arrhythmia or ictal asystole, and "sudden unexpected death in epilepsy" (SUDEP) is an important field of epilepsy research. Cardiac channelopathies such as long QT syndrome may be associated with seizures, suggesting a possible link between cardiac and cerebral channelopathy. We here review in detail cardiac effects due to epileptic seizures as well as possible pathogenetic correlations between cardiac and epileptic diseases.


Assuntos
Arritmias Cardíacas/etiologia , Morte Súbita Cardíaca/etiologia , Epilepsia/complicações , Parada Cardíaca/etiologia , Síncope/etiologia , Anticonvulsivantes/uso terapêutico , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/terapia , Bradicardia/diagnóstico , Bradicardia/etiologia , Bradicardia/fisiopatologia , Bradicardia/terapia , Comportamento Cooperativo , Morte Súbita Cardíaca/prevenção & controle , Eletrocardiografia , Eletroencefalografia , Epilepsia/diagnóstico , Epilepsia/fisiopatologia , Epilepsia/terapia , Parada Cardíaca/diagnóstico , Frequência Cardíaca/fisiologia , Humanos , Comunicação Interdisciplinar , Síndrome do QT Longo/complicações , Síndrome do QT Longo/diagnóstico , Síndrome do QT Longo/fisiopatologia , Síndrome do QT Longo/terapia , Marca-Passo Artificial , Equipe de Assistência ao Paciente , Fatores de Risco , Processamento de Sinais Assistido por Computador , Síncope/fisiopatologia , Taquicardia/diagnóstico , Taquicardia/etiologia , Taquicardia/fisiopatologia , Taquicardia/terapia
11.
Intern Med J ; 41(6): 467-72, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20214692

RESUMO

BACKGROUND: Worsening renal function (WRF) is frequently observed in patients with heart failure and is associated with worse outcome. The aim of this study was to examine the association of the cardiac serum marker N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and WRF. METHODS: A total of 125 consecutive patients of a tertiary care outpatient clinic for heart failure prospectively underwent evaluation of renal function every 6 months. The association of baseline NT-pro-BNP with WRF was analysed during a follow up of 18 months. RESULTS: Twenty-eight (22.4%) patients developed WRF (increase in serum creatinine ≥0.3 mg/dL). Patients with WRF (2870 pg/mL, interquartile range (IQR) 1063-4765) had significantly higher baseline NT-pro-BNP values than patients without WRF (547 pg/mL, IQR 173-1454). The risk for WRF increased by 4.0 (95% CI 2.1-7.5) for each standard deviation of log NT-pro-BNP. In multivariable analysis including age, baseline renal function, ejection fraction, New York Heart Association class and diuretic dose, only NT-pro-BNP and diabetes were independent predictors of WRF. At a cut-off level of 696 pg/mL, NT-pro-BNP showed a sensitivity of 92.9% and a negative predictive value of 96.4% for WRF. CONCLUSION: NT-pro-BNP is a strong independent predictor of WRF within 18 months in patients with systolic heart failure with a high negative predictive value. Further studies are needed to evaluate reno-protective strategies in patients with elevated NT-pro-BNP.


Assuntos
Insuficiência Cardíaca Sistólica/sangue , Insuficiência Cardíaca Sistólica/fisiopatologia , Nefropatias/sangue , Nefropatias/fisiopatologia , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Precursores de Proteínas/sangue , Idoso , Biomarcadores/sangue , Doença Crônica , Progressão da Doença , Feminino , Insuficiência Cardíaca Sistólica/complicações , Humanos , Nefropatias/etiologia , Testes de Função Renal/tendências , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/fisiologia , Fragmentos de Peptídeos/fisiologia , Valor Preditivo dos Testes , Precursores de Proteínas/fisiologia
12.
Fortschr Neurol Psychiatr ; 78(7): 419-24, 2010 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-20533164

RESUMO

Syncope is a common and difficult differential diagnosis for epilepsy. One possible cause for a cardiac syncope is a long QT syndrome (LQTS). LQTS with torsade de pointes tachycardia can lead to lethal ventricular fibrillation and cardiac arrest. Patients with LQTS when first diagnosed as suffering from epileptic fits often experience a particularly long diagnostic delay which may even take years. In some cases, the diagnosis of LQTS is not made until the patient needs resuscitation due to a cardiac arrest. Therefore, ECG recording should be performed for every patient presenting with a seizure considered to be of epileptic origin not only at the beginning of the disease but also when fits occur in spite of antiepileptic treatment in order to prevent an incorrect diagnosis and delay in making the correct diagnosis.


Assuntos
Eletrocardiografia , Epilepsia/diagnóstico , Síndrome do QT Longo/diagnóstico , Convulsões/etiologia , Adolescente , Anticonvulsivantes/uso terapêutico , Arritmias Cardíacas , Diagnóstico Diferencial , Eletroencefalografia , Testes de Função Cardíaca , Humanos , Síndrome do QT Longo/tratamento farmacológico , Masculino , Torsades de Pointes/complicações , Torsades de Pointes/diagnóstico , Fibrilação Ventricular/diagnóstico
13.
Physiol Res ; 59(5): 679-689, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20406048

RESUMO

The present study investigated cardiac function in hearts of mice with total deficiency of the beta1-, beta2- and beta3-adrenoceptors (TKO) in comparison to wildtype mice (WT). We investigated cardiac morphology and echocardiographic function, measured protein expression of Ca2+-regulatory proteins, SERCA 2a activity, myofibrillar function, and performed running wheel tests. Heart weight and heart-to-body weight ratio were significantly smaller in TKO as compared to WT. This was accompanied by a decrease in the size of the cardiomyocytes in TKO. Heart rate and ejection fraction were significantly diminished in TKO as compared to WT. Protein expressions of SERCA 2a, ryanodine receptor and Na+/Ca2)-exchanger were similar in TKO and WT mice, but phospholamban protein expression was increased. PKA-dependent phosphorylation of phospholamban at serine 16 was absent and CaMKII-dependent phosphorylation at threonine 17 was decreased in TKO. All alterations were paralleled by a decrease in SERCA 2a-activity. A similar maximal calcium-dependent tension but an increased myofibrillar calcium-sensitivity was measured in TKO as compared to WT. We did not observe relevant functional impairments of TKO in running wheel tests. In the absence of beta-agonistic stimulation, SERCA 2a activity is mainly regulated by alterations of phospholamban expression and phosphorylation. The decreased SERCA 2a activity following beta-adrenoceptor deficiency may be partly compensated by an increased myofibrillar calcium-sensitivity.


Assuntos
Cardiomegalia/fisiopatologia , Contração Miocárdica/fisiologia , Receptores Adrenérgicos beta 1/genética , Receptores Adrenérgicos beta 2/genética , Receptores Adrenérgicos beta 3/genética , Animais , Cardiomegalia/diagnóstico por imagem , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Ecocardiografia , Feminino , Camundongos , Camundongos Knockout , Miofibrilas/fisiologia , Fosforilação/fisiologia , Condicionamento Físico Animal/fisiologia , Receptores Adrenérgicos beta 1/deficiência , Receptores Adrenérgicos beta 2/deficiência , Receptores Adrenérgicos beta 3/deficiência , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/metabolismo
14.
J Cardiovasc Pharmacol ; 54(1): 10-5, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19487957

RESUMO

BACKGROUND: The Na,K-ATPase (NKA) is necessary for maintaining the resting membrane potential by transporting Na and K ions across the cell membrane. Although its 3 isoforms expressed in human heart (alpha1beta1, alpha2beta1, and alpha3beta1) possess similar biochemical properties, their specific functions in human tissues remain unknown. In our search for an isoform-specific agent, which can serve to identify isoform-specific functions, we examined 8-methoxycoumestrol in its ability to inhibit the NKA and to produce inotropism in connection with the possibility to identify the NKA isoform-specific functions. METHODS AND RESULTS: In radioligand binding experiments (membrane preparations of yeast expressing isoforms alpha1beta1, alpha2beta1, and alpha3beta1; backdoor phosphorylation; and [H]-ouabain, n = 3), 8-methoxycoumestrol (1-10 microM) produced no or only little inhibition of specific ouabain binding. However, when NKA activity of the alpha1beta1 isoform was measured in membrane preparations from human kidney (reduced form of nicotinamide adenine dinucleotide-coupled assay, n = 3), a concentration-dependent full inhibition of the activity was induced by 8-methoxycoumestrol (IC50: 90 +/- 97 nM), similar to that observed for classical cardiac glycosides digitoxin, digoxin, methyldigoxin, and beta-acetyldigoxin (IC50 = 287 +/- 190 nM, 409 +/- 171 nM, 282 +/- 482 nM, 587 +/- 135 nM, P > 0.05). However, unlike the classical cardiac glycosides, 8-methoxycoumestrol did not increase cardiac contractility of electrically stimulated human right atrial trabeculae. CONCLUSIONS: These results indicate that 8-methoxycoumestrol inhibits the human alpha1beta1 NKA by a mechanism different to that of cardiac glycosides. In addition, the inhibition of the alpha1beta1 NKA activity seems not sufficient to evoke positive inotropy in human trabeculae, indicating that either the positive inotropic effect of cardiac glycosides is not mediated via the alpha1beta1 isoform or the specific glycoside binding to alpha1beta1 is needed for positive inotropy.


Assuntos
Glicosídeos Cardíacos/farmacologia , Cumestrol/análogos & derivados , Cumestrol/farmacologia , Inibidores Enzimáticos/farmacologia , Miocárdio/metabolismo , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Idoso , Cumestrol/síntese química , Cumestrol/química , Cumestrol/metabolismo , Relação Dose-Resposta a Droga , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/fisiopatologia , Humanos , Concentração Inibidora 50 , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Rim/metabolismo , Rim/cirurgia , Masculino , Pessoa de Meia-Idade , Estrutura Molecular , Contração Muscular/fisiologia , Nefrectomia , ATPase Trocadora de Sódio-Potássio/genética , ATPase Trocadora de Sódio-Potássio/metabolismo , Temperatura , Fatores de Tempo
16.
Diabet Med ; 25(2): 228-31, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18028437

RESUMO

AIMS: The influence of dynamic changes in glycated haemoglobin (HbA(1c)) on restenosis after elective percutaneous coronary intervention (PCI) in patients without diabetes has not been analysed. Therefore, the rate of restenosis was investigated after elective PCI in 101 consecutive patients without diabetes mellitus in relation to dynamic changes of HbA(1c) levels. METHODS: Follow-up angiography was performed in all patients 4-6 months after intervention. RESULTS: Multivariate analysis demonstrated that the change in HbA(1c) between first and second coronary angiography was the most powerful metabolic parameter for prediction of restenosis. The odds ratio for restenosis was 3.0 (95% CI 1.0-9.0) for any increase in HbA(1c) and 1.9 (95% CI 1.1-3.5) for an HbA(1c) increase of 0.2%. CONCLUSIONS: Hence, chronic changes in the glucometabolic environment influence the incidence of restenosis after PCI in patients without diabetes.


Assuntos
Reestenose Coronária/etiologia , Hemoglobinas Glicadas/metabolismo , Angioplastia Coronária com Balão , Glicemia/metabolismo , Reestenose Coronária/metabolismo , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Stents
17.
J Int Med Res ; 35(6): 803-18, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18034994

RESUMO

Cardiac hypertrophy is an independent risk factor for heart failure. Recent studies on gene regulation of proteins have involved intracellular Ca2+ homeostasis. The Ca2+-sensitive phosphatase, calcineurin, is one potential regulator of the hypertrophic response, so we aimed to investigate the calcineurin-dependent signal pathway at different stages of hypertrophy in human myocardium. We found the calcineurin pathway to be significantly activated in hypertrophic compared with non-hypertrophic myocardium as demonstrated by increased calcineurin activity and expression of calcineurin A-beta and B, and GATA-4, and a shift of phosphorylated cytoplasmic NFAT-3 into the nucleus as dephosphorylated nuclear NFAT-3. There was a tendency for these changes to be more pronounced in the decompensated compared with the compensated hypertrophic myocardium. The present study provides evidence for significant activation of the Ca2+-triggered calcineurin pathway in hypertrophic humans. Already present in compensated hypertrophy it showed a tendency to a further increase following transition to decompensated hypertrophy.


Assuntos
Calcineurina/metabolismo , Hipertrofia , Miocárdio , Fatores de Transcrição NFATC/metabolismo , Transdução de Sinais/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Cálcio/metabolismo , Feminino , Fator de Transcrição GATA4/metabolismo , Insuficiência Cardíaca/etiologia , Humanos , Hipertrofia/metabolismo , Hipertrofia/patologia , Masculino , Pessoa de Meia-Idade , Miocárdio/metabolismo , Miocárdio/patologia , Isoformas de Proteínas/metabolismo , Fatores de Risco
18.
Clin Res Cardiol ; 96(9): 621-7, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17676354

RESUMO

OBJECTIVE: Circulating progenitor cells (CPC) may contribute to cardiac regeneration and neovascularization after acute myocardial infarction (AMI). For potential therapeutic use, understanding the endogenous mechanisms after ischemia is inevitable. We investigated the absolute number, but also the subset composition of CD34+ CPC after AMI. METHODS: CD34+, KDR+/CD34+, CD133+/CD34+ and CD117+/CD34+CPC were analyzed by FACS in peripheral blood of 10 patients with acute MI (59+/-5 yrs, m/f=8/2) at day of AMI (day 0) and days 1-5. For comparison patients with stable coronary artery disease (CAD, n=12, 66+/-2 yrs, m/f=10/2) and young healthy volunteers (n=7, 26+/-2 yrs, m/f=3/4) were studied. RESULTS: CD34 and KDR/CD34, CD133/CD34, CD117/CD34 were increased day 3 and 4 after AMI. KDR+ fraction within CD34+ population remained unchanged (58.3+/-7.8% vs 55.3+/-10.6%), whereas CD133+ (64.9+/-3.1% vs 43.5+/-5.9%, P=0.006) and CD117+ fractions (71.7+/-5.6% vs 50.1+/-5.5%, P=0.02) were elevated. In CAD, all CPC and fractions were similar as AMI day 0. Healthy volunteers had more CD34+ than CAD and AMI day 0. Double positive CPC were also higher, but fractions were unchanged vs CAD with more KDR/CD34 in trend (72.8+/-10.6% vs 50.5+/-5.6%, P=0.058). After AMI both absolute numbers of CD34+ and their subset composition change, suggesting selective mobilization of CPC. Increased CPC after AMI never reach numbers of young healthy volunteers.


Assuntos
Antígenos CD34/sangue , Antígenos CD/sangue , Glicoproteínas/sangue , Células-Tronco Hematopoéticas/metabolismo , Infarto do Miocárdio/sangue , Peptídeos/sangue , Proteínas Proto-Oncogênicas c-kit/sangue , Antígeno AC133 , Adulto , Idoso , Estudos de Casos e Controles , Doença da Artéria Coronariana/sangue , Feminino , Mobilização de Células-Tronco Hematopoéticas , Humanos , Leucócitos Mononucleares/metabolismo , Masculino , Pessoa de Meia-Idade , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/sangue
19.
Diabetologia ; 49(12): 3067-74, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17051401

RESUMO

AIMS/HYPOTHESIS: The angiotensin II (type 1) (AT1) receptor mediates many biological effects of the renin-angiotensin system (RAS), leading to remodelling of cardiac tissue. The present study was designed to analyse changes in the function and expression of the AT1 receptor as principal effector of the RAS in myocardium from type 2 diabetic patients compared with non-diabetic myocardium as control. In addition, we determined the effect of treatment with ACE inhibitors or AT1 receptor blockers on expression levels of the receptor in diabetic patients. METHODS: Gene expression of the AT1 receptor was analysed by quantitative RT-PCR and protein expression was determined by immunoblot analysis in human right atrial myocardium. We investigated functional coupling of the receptors by measuring contractility in isolated trabeculae stimulated with increasing concentrations of angiotensin II. RESULTS: Diabetic myocardium showed a significant increase in protein expression (170 +/- 16% of control) and median mRNA expression (186% of control) of the AT1 receptor. The additional receptors were functionally coupled, resulting in a stronger inotropic response upon stimulation with angiotensin II (89 +/- 5.5% vs 29 +/- 1.6% in controls), whereas receptor affinity was similar in both groups. However, myocardium from diabetic patients treated with ACE inhibitors or AT1 receptor blockers showed no increase in AT1 receptor expression. CONCLUSIONS/INTERPRETATION: AT1 receptor expression in myocardium of type 2 diabetic patients is dynamic, depending on the level of glycaemic control and the activity of the RAS. These findings could at least in part explain the strong therapeutic benefit of RAS inhibition in diabetic patients.


Assuntos
Angiotensina II/farmacologia , Diabetes Mellitus Tipo 2/fisiopatologia , Miocárdio/metabolismo , Receptor Tipo 1 de Angiotensina/genética , Sistema Renina-Angiotensina/fisiologia , Idoso , Biópsia , Diabetes Mellitus Tipo 2/sangue , Feminino , Hemoglobinas Glicadas/metabolismo , Átrios do Coração/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Contração Muscular , Relaxamento Muscular , Músculo Esquelético/citologia , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , RNA Mensageiro/genética , Receptor Tipo 1 de Angiotensina/metabolismo , Valores de Referência , Sistema Renina-Angiotensina/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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