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INTRODUCTION: Survival of patients suffering from metastatic colorectal cancer (mCRC) has increased over the last decades. These benefits appear to be restricted to patients aged 50 and above. However, among the population aged <50, colorectal cancer incidence and mortality rates are significantly rising. The clinical benefit of treatment in this population still is a matter of debate. We aim to compare the clinical outcome between patients aged 50 and younger. METHODS: In this retrospective, observational study, we analyzed data from 1,077 patients treated for mCRC at three cancer centers in Austria from January 2005 to December 2019. Patients were divided into two groups based on age at diagnosis: <50 years (eo-CRC) and >50 years (regular-onset CRC, ro-CRC). Propensity score matching was used to control for potential biases, and survival outcomes were compared between the two groups. RESULTS: The differences in tumor characteristics between eo-CRC and ro-CRC in the overall population were primarily related to tumor sidedness and disease-free survival following intended curative resection. Our data show that eo-CRC patients underwent metastases resection more often and received significantly more lines of treatment in the palliative setting. Overall survival was superior in eo-CRC compared to ro-CRC, even after adjusting for sidedness, timing of metastases, sex, number of treatment lines, and resection of metastases by propensity scoring. CONCLUSION: Our study suggests that younger patients benefit at least to the same magnitude or even more from mCRC-treatment than patients aged 50 or above.
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Neoplasias do Colo , Neoplasias Colorretais , Neoplasias Retais , Humanos , Neoplasias Colorretais/patologia , Estudos Retrospectivos , Análise por PareamentoRESUMO
PURPOSE OF REVIEW: This review will explore various strategies to rendering MSS mCRCs susceptible to ICI. Moreover, we will provide an overview of potential biomarkers that may aid to better patient selection, and discuss ongoing efforts in this area of research. RECENT FINDINGS: Colorectal cancer (CRC) ranks among the top three most common cancers worldwide. While significant advances in treatment strategies have improved the prognosis for patients in the early stages of the disease, treatment options for metastatic CRC (mCRC) remain limited. Although immune checkpoint inhibitors (ICI) have revolutionized the treatment of several malignancies, its efficacy in mCRC is largely confined to patients exhibiting a high microsatellite instability status (MSI-H). However, the vast majority of mCRC patients do not exhibit a MSI-H, but are microsatellite stable (MSS). In these patients ICIs are largely ineffective. So far, ICIs do not play a crucial role in patients with MSS mCRC, despite the promising data for inducing long-term remissions in other tumour entities. For this reason, novel treatment strategies are needed to overcome the primary resistance upon ICI in patients with MSS.
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BACKGROUND: Adenocarcinoma of the esophagogastric junction (AEG) is a rare but rising tumor entity in the Western world. Treatment is complex, as multimodality is key to optimal results. However, trials solely including AEG are rare, and the question if neoadjuvant radiochemotherapy (NRCT) or neoadjuvant/perioperative chemotherapy (NACT) is superior remains unanswered. PATIENTS AND METHODS: Patients with AEG I-III treated between October 2010 and August 2019 at the Ordensklinikum Linz or the Kepler University Hospital were identified either from a monitored tumor registry or by chart review. Time-to-event data were analyzed by Kaplan-Meier product limit estimation. The Kruskal-Wallis test and Fisher's exact test were used for comparing continuous and categorical data, respectively. RESULTS: A total of 85 patients (median age 63 years; median Charlson Comorbidity Index 3; 98.8% ECOG PS 0-1) were analyzed. Of these, 52 patients received NRCT (81% CROSS protocol) and 33 NACT (65% EOX and 35% FLOT protocol). There was a significantly higher pathological complete response rate in the NRCT group (30 vs. 12%; p = 0.010); distant relapse rates were higher in the NRCT group and local relapse rates were higher in the NACT group (both not significant). These differences, however, did not translate into a different disease-free survival (20 months; 95% CI: 13-34) or overall survival (44 months; 95% CI: 33-NA). Patients >65 years old had the same advantage from treatment as patients <65 years of age. CONCLUSIONS: Although treatment of AEG is complex, the progress documented over the last centuries can be reproduced in our real-life setting. Data regarding the superiority of either type of neoadjuvant/perioperative treatment are sparse. We assume no difference between EOX-based NACT and NRCT.
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Neoplasias Esofágicas/terapia , Junção Esofagogástrica/patologia , Neoplasias Gástricas/terapia , Idoso , Quimiorradioterapia Adjuvante , Estudos de Coortes , Intervalo Livre de Doença , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/cirurgia , Junção Esofagogástrica/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Assistência Perioperatória , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Taxa de Sobrevida , Resultado do TratamentoRESUMO
Sirolimus (rapamycin) is used in drug-eluting stent strategies and proved clearly superior in this application compared with other immunomodulators such as pimecrolimus. The molecular basis of this action of sirolimus in the vascular system is still incompletely understood. Measurements of cell proliferation in human coronary artery smooth muscle cells (hCASM) demonstrated a higher antiproliferative activity of sirolimus compared with pimecrolimus. Although sirolimus lacks inhibitory effects on calcineurin, nuclear factor of activated T-cell activation in hCASM was suppressed to a similar extent by both drugs at 10 µM. Sirolimus, but not pimecrolimus, inhibited agonist-induced and store-operated Ca(2+) entry as well as cAMP response element binding protein (CREB) phosphorylation in human arterial smooth muscle, suggesting the existence of an as-yet unrecognized inhibitory effect of sirolimus on Ca(2+) signaling and Ca(2+)-dependent gene transcription. Electrophysiological experiments revealed that only sirolimus but not pimecrolimus significantly blocked the classical stromal interaction molecule/Orai-mediated, store-operated Ca(2+) current reconstituted in human embryonic kidney cells (HEK293). A link between Orai function and proliferation was confirmed by dominant-negative knockout of Orai in hCASM. Analysis of the effects of sirolimus on cell proliferation and CREB activation in an in vitro model of arterial intervention using human aorta corroborated the ability of sirolimus to suppress stent implantation-induced CREB activation in human arteries. We suggest inhibition of store-operated Ca(2+) entry based on Orai channels and the resulting suppression of Ca(2+) transcription coupling as a key mechanism underlying the antiproliferative activity of sirolimus in human arteries. This mechanism of action is specific for sirolimus and not a general feature of drugs interacting with FK506-binding proteins.
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Canais de Cálcio/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Fármacos Cardiovasculares/farmacologia , Proliferação de Células/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Sirolimo/farmacologia , Stents/efeitos adversos , Aorta/efeitos dos fármacos , Aorta/metabolismo , Aorta/patologia , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/metabolismo , Vasos Coronários/patologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Relação Dose-Resposta a Droga , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Hiperplasia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Fatores de Transcrição NFATC/metabolismo , Proteína ORAI1 , Fosforilação , Tacrolimo/análogos & derivados , Tacrolimo/farmacologia , Fatores de Tempo , Técnicas de Cultura de Tecidos , Transcrição Gênica/efeitos dos fármacos , TransfecçãoRESUMO
Background: Serial analysis of circulating tumor DNA (ctDNA) levels is a promising tool for both relapse prediction in the curative setting, as well as predicting clinical benefit from systemic treatment in metastasic colorectal cancer (mCRC). Most data in this context are derived from treatment naive patients. Objective: To predict progressive disease (PD) as early as possible through monitoring of changes in ctDNA levels during systemic treatment in pretreated patients with mCRC. Design: A prospective, single-center, observational study. Methods: Patients treated beyond first-line were prospectively included between February 2020 and September 2021. Blood for ctDNA detection was taken before every treatment cycle from start of treatment until first restaging by CT-scan. ctDNA was detected by mutation- (mut-ctDNA) and methylation-specific ddPCR. Receiver Operating Characteristic (ROC)-analysis was used to describe sensitivity and specificity for prediction of PD at restaging for all time points. Results: A total of 42 patients were included who all carried a mutation in tumor tissue. Detection rate of mut-ctDNA was 88.1% and 74.4% for meth-ctDNA. Absolute ctDNA levels before treatment were prognostic in terms of overall survival. Levels of ctDNA were significantly higher in patients with PD at restaging. Median time from start of treatment to restaging was 93 days (95% CI 88.8-96). After a median of 19 days of treatment (95% CI 16.1-20.2), a decline of either mutation- or methylation-specific ctDNA levels of ⩽58% predicted PD at restaging with a sensitivity/specificity of 92.9/85.7% and 85.7/100%, respectively. Median time to restaging was 66 days (95% CI 56.8-75.2). There was no significant increase of sensitivity/specificity at later time points of ctDNA measurements. Conclusion: Monitoring early changes of ctDNA levels either by mut- or meth-ctDNA allows for early prediction of PD in pretreated patients with mCRC. This has the potential to complement RECIST-based treatment assessment with the aim to switch potentially insufficient treatments as early as possible, which is of particular interest in higher treatment lines.
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Biliary tract cancers are rare cancers with poor prognosis due to a lack of therapeutic options, especially after the failure of first-line systemic treatment. Targeted treatments for this clinical situation are promising and have entered clinical practice. We aimed to describe the overall survival of matched targeted treatment after first-line treatment in patients with biliary tract cancers in an Austrian real-world multicenter cohort. We performed a multicenter retrospective chart review of patients with biliary tract cancer between September 2015 and January 2022. Data, including comprehensive molecular characteristics-next generation sequencing (NGS) and immunohistochemistry (IHC), clinical history, surgical procedures, ablative treatments, patient history, and systemic chemotherapy, were extracted from the records of the participating institutions. Targeted treatment was matched according to the ESMO scale for the clinical actionability of molecular targets (ESCAT). We identified 159 patients with the available molecular characteristics. A total of 79 patients underwent second-line treatment. Of these, 36 patients received matched targeted treatment beyond the first-line and were compared with 43 patients treated with cytotoxic chemotherapy in terms of efficacy outcomes. For Tier I/II alterations, we observed a progression free survival ratio (PFStargeted/PFSpre-chemotherapy) of 1.86, p = 0.059. The overall survival for patients receiving at least two lines of systemic treatment significantly favored the targeted approach, with an overall survival of 22.3 months (95% CI 14.7-29.3) vs. 17.5 months (95% CI 1.7-19.8; p = 0.048). Our results underscore the value of targeted treatment approaches based on extended molecular characterization of biliary tract cancer to improve clinical outcomes.
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Neoplasias do Sistema Biliar , Humanos , Estudos Retrospectivos , Neoplasias do Sistema Biliar/tratamento farmacológico , Administração Cutânea , Áustria , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
OBJECTIVES: To examine the acute effects of sunitinib on inotropic function, intracellular Ca(2+) transients, myofilament Ca(2+) sensitivity and generation of reactive oxygen species (ROS) in human multicellular myocardium and isolated mouse cardiomyocytes. To search for microRNAs as suitable biomarkers for indicating toxic cardiac effects. PATIENTS AND METHODS: After exposure to sunitinib (0.1-10 µg/mL) developed force, diastolic tension and kinetic variables were assessed in isolated human myocardium. Changes in myocyte sarcomere length, whole-cell calcium transients, myofilament force-Ca(2+) relationship, and ROS generation were examined in isolated ventricular mouse cardiomyocytes. Microarray and realtime-PCR were used to screen for differentially expressed microRNAs in cultured cardiomyocytes that were exposed for 24 h to sunitinib. RESULTS: We found that higher concentrations of sunitinib (1 and 10 µg/mL) decreased developed force at 30 minutes 76.9 + 2.8 and 54.5 + 6.3%, compared to 96.1 + 2.6% in controls (P < 0.01). Sunitinib exposure significantly decreased sarcomere shortening and Ca2+ transients. Myofilament Ca(2+) sensitivity was not altered, while ROS levels were significantly increased after exposure to the drug. MicroRNA expression patterns were not altered by sunitinib. CONCLUSIONS: Sunitinib elicits a dose-dependent negative inotropic effect in myocardium, accompanied by a decline in intracellular Ca(2+) and increased ROS generation. In clinical practice, these cardiotoxic effects should be considered in cases where cardiac concentrations of sunitinib could be increased.
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Antineoplásicos/efeitos adversos , Indóis/efeitos adversos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Inibidores de Proteínas Quinases/efeitos adversos , Pirróis/efeitos adversos , Idoso , Animais , Cálcio/metabolismo , Relação Dose-Resposta a Droga , Espectroscopia de Ressonância de Spin Eletrônica , Feminino , Coração/efeitos dos fármacos , Humanos , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sarcômeros/efeitos dos fármacos , SunitinibeRESUMO
Anti-EGFR targeting is one of the key strategies in the treatment of metastatic colorectal cancer (mCRC). For almost two decades oncologists have struggled to implement EGFR antibodies in the mCRC continuum of care. Both sidedness and RAS mutational status rank high among the predictive factors for the clinical efficacy of EGFR inhibitors. A prospective phase III trial has recently confirmed that anti-EGFR targeting confers an overall survival benefit only in left sided RAS-wildtype tumors when given in first line. It is a matter of discussion if more clinical benefit can be reached by considering putative primary resistance mechanisms (e.g., HER2, BRAF, PIK3CA, etc.) at this early stage of treatment. The value of this procedure in daily routine clinical utility has not yet been clearly delineated. Re-exposure to EGFR antibodies becomes increasingly crucial in the disease journey of mCRC. Yet re- induction or re-challenge strategies have been problematic as they relied on mathematical models that described the timely decay of EGFR antibody resistant clones. The advent of liquid biopsy and the implementation of more accurate next-generation sequencing (NGS) based high throughput methods allows for tracing of EGFR resistant clones in real time. These displays the spatiotemporal heterogeneity of metastatic disease compared to the former standard radiographic assessment and re-biopsy. These techniques may move EGFR inhibition in mCRC into the area of precision medicine in order to apply EGFR antibodies with the increase or decrease of EGFR resistant clones. This review critically discusses established concepts of tackling the EGFR pathway in mCRC and provides insight into the growing field of liquid biopsy guided personalized approaches of EGFR inhibition in mCRC.
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In the Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) clinicolaboratory real-life data have been captured from 606 CMML patients from 14 different hospitals over the last 30 years. It is the only large biodatabase worldwide in which functional methods such as semisolid in vitro cultures complement modern molecular methods such as next generation sequencing. This provides the possibility to comprehensively study the biology of CMML. The aim of this study was to compare patient characteristics with published CMML cohorts and to validate established prognostic parameters in order to examine if this real-life database can serve as a representative and useful data source for further research. After exclusion of patients in transformation characteristics of 531 patients were compared with published CMML cohorts. Median values for age, leukocytes, hemoglobin, platelets, lactate dehydrogenase (LDH) and circulating blasts were within the ranges of reported CMML series. Established prognostic parameters including leukocytes, hemoglobin, blasts and adverse cytogenetics were able to discriminate patients with different outcome. Myeloproliferative (MP) as compared to myelodysplastic (MD)-CMML patients had higher values for circulating blasts, LDH, RAS-pathway mutations and for spontaneous myelomonocytic colony growth in vitro as well as more often splenomegaly. This study demonstrates that the patient cohort of the ABCMML shares clinicolaboratory characteristics with reported CMML cohorts from other countries and confirms phenotypic and genotypic differences between MP-CMML and MD-CMML. Therefore, results obtained from molecular and biological analyses using material from the national cohort will also be applicable to other CMML series and thus may have a more general significance.
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Pesquisa Biomédica , Leucemia Mielomonocítica Crônica , Adulto , Idoso , Idoso de 80 Anos ou mais , Áustria , Feminino , Humanos , Armazenamento e Recuperação da Informação , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto JovemRESUMO
A female patient with oestrogen receptor-positive and human epidermal growth factor receptor 2 (HER2)-positive invasive lobular breast cancer presented with progressive disease on CT scan. Some days after initiation of antineoplastic chemotherapy and anti-HER2 targeted antibody therapy, the patient presented with profuse diarrhoea, neutropaenia, nausea and weakness. Although Clostridium difficile was rapidly tackled as a causative agent of gastrointestinal complaints, clinical situation did not markedly improve despite proper antimicrobial treatment. The patient reported profound lack of energy, while nausea, vomiting and loose stools still persisted. Additionally slightly exaggerated pigmentation of nonsunexposed skin and mucosal areas led us to the assumption of proopiomelanocortin-derived peptide hypersecretion. The combination of highly elevated adrenocorticotropic hormone and low basal cortisol levels taken from a morning blood sample established the diagnosis of adrenal insufficiency due to metastatic burden, leading to a near Addison crisis by gastrointestinal complications of chemo-immune therapy. Administration of hydrocortisone immediately relieved general symptoms .
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Insuficiência Adrenal/induzido quimicamente , Neoplasias da Mama/tratamento farmacológico , Inibidores de Proteínas Quinases/efeitos adversos , Insuficiência Adrenal/tratamento farmacológico , Neoplasias da Mama/complicações , Neoplasias da Mama/metabolismo , Feminino , Humanos , Hidrocortisona/uso terapêutico , Pessoa de Meia-Idade , Metástase Neoplásica , Inibidores de Proteínas Quinases/uso terapêutico , Receptor ErbB-2/metabolismoRESUMO
Histoplasmosis is well characterized as an endemic fungal disease restricted to certain areas of the USA. In Middle Europe, most patients present with acute pulmonary symptoms after travelling to endemic areas. Here, we want to illustrate the case of a 67-year-old man who presented with persistent oral ulcers, hoarseness, dysphagia, diarrhea, and weight loss to our Department of Otorhinolaryngology in December 2014. He was a retired construction worker and had a history of soil-disruptive activities in Africa and Middle and South America during employment. A positron emission tomography-computed tomography scan revealed prominent hypermetabolic lesions in the cecum and the lung, pointing towards a malignant disease. Surprisingly, histological examination of colonic and oral biopsies revealed abundant intracellular fungal elements, highly suspicious of Histoplasma capsulatum. Diagnosis was finally confirmed by panfungal polymerase chain reaction. Upon treatment with liposomal amphotericin followed by itraconazole, the severely ill patient showed an impressive clinical response. This case describes a disseminated manifestation of H. capsulatum years after the first exposure in an otherwise immunocompetent patient descending from a nonendemic area.
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AIM: TRPC3 is a non-selective cation channel, which forms a Ca2+ entry pathway involved in cardiac remodelling. Our aim was to analyse acute electrophysiological and contractile consequences of TRPC3 activation in the heart. METHODS AND RESULTS: We used a murine model of cardiac TRPC3 overexpression and a novel TRPC3 agonist, GSK1702934A, to uncover (patho)physiological functions of TRPC3. GSK1702934A induced a transient, non-selective conductance and prolonged action potentials in TRPC3-overexpressing myocytes but lacked significant electrophysiological effects in wild-type myocytes. GSK1702934A transiently enhanced contractility and evoked arrhythmias in isolated Langendorff hearts from TRPC3-overexpressing but not wild-type mice. Interestingly, pro-arrhythmic effects outlasted TRPC3 current activation, were prevented by enhanced intracellular Ca2+ buffering, and suppressed by the NCX inhibitor 3',4'-dichlorobenzamil hydrochloride. GSK1702934A substantially promoted NCX currents in TRPC3-overexpressing myocytes. The TRPC3-dependent electrophysiologic, pro-arrhythmic, and inotropic actions of GSK1702934A were mimicked by angiotensin II (AngII). Immunocytochemistry demonstrated colocalization of TRPC3 with NCX1 and disruption of local interaction upon channel activation by either GSK1702934A or AngII. CONCLUSION: Cardiac TRPC3 mediates Ca2+ and Na+ entry in proximity of NCX1, thereby elevating cellular Ca2+ levels and contractility. Excessive activation of TRPC3 is associated with transient cellular Ca2+ overload, spatial uncoupling between TRPC3 and NCX1, and arrhythmogenesis. We propose TRPC3-NCX micro/nanodomain communication as determinant of cardiac contractility and susceptibility to arrhythmogenic stimuli.
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Arritmias Cardíacas/fisiopatologia , Contração Miocárdica/fisiologia , Transdução de Sinais/fisiologia , Trocador de Sódio e Cálcio/fisiologia , Canais de Cátion TRPC/fisiologia , Potenciais de Ação/fisiologia , Animais , Arritmias Cardíacas/patologia , Cálcio/fisiologia , Modelos Animais de Doenças , Técnicas Eletrofisiológicas Cardíacas , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Miócitos Cardíacos/patologia , Miócitos Cardíacos/fisiologia , Técnicas de Patch-Clamp , Canais de Cátion TRPC/agonistas , Canais de Cátion TRPC/genéticaRESUMO
OBJECTIVE: High bile acid serum concentrations have been implicated in cardiac disease, particularly in arrhythmias. Most data originate from in vitro studies and animal models. We tested the hypotheses that (1) high bile acid concentrations are arrhythmogenic in adult human myocardium, (2) serum bile acid concentrations and composition are altered in patients with atrial fibrillation (AF) and (3) the therapeutically used ursodeoxycholic acid has different effects than other potentially toxic bile acids. METHODS AND RESULTS: Multicellular human atrial preparations ('trabeculae') were exposed to primary bile acids and the incidence of arrhythmic events was assessed. Bile acid concentrations were measured in serum samples from 250 patients and their association with AF and ECG parameters analysed. Additionally, we conducted electrophysiological studies in murine myocytes. Taurocholic acid (TCA) concentration-dependently induced arrhythmias in atrial trabeculae (14/28 at 300 µM TCA, p<0.01) while ursodeoxycholic acid did not. Patients with AF had significantly decreased serum levels of ursodeoxycholic acid conjugates and increased levels of non-ursodeoxycholic bile acids. In isolated myocytes, TCA depolarised the resting membrane potential, enhanced Na(+)/Ca(2+) exchanger (NCX) tail current density and induced afterdepolarisations. Inhibition of NCX prevented arrhythmias in atrial trabeculae. CONCLUSIONS: High TCA concentrations induce arrhythmias in adult human atria while ursodeoxycholic acid does not. AF is associated with higher serum levels of non-ursodeoxycholic bile acid conjugates and low levels of ursodeoxycholic acid conjugates. These data suggest that higher levels of toxic (arrhythmogenic) and low levels of protective bile acids create a milieu with a decreased arrhythmic threshold and thus may facilitate arrhythmic events.
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Fibrilação Atrial/sangue , Fibrilação Atrial/etiologia , Ácidos e Sais Biliares/sangue , Ácidos e Sais Biliares/farmacologia , Átrios do Coração/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Idoso , Animais , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/fisiologia , Eletrofisiologia Cardíaca , Feminino , Humanos , Masculino , Camundongos , Ácido Taurocólico/farmacologia , Ácido Ursodesoxicólico/farmacologiaRESUMO
BACKGROUND AND PURPOSE: Urocortin 2 is beneficial in heart failure, but the underlying cellular mechanisms are not completely understood. Here we have characterized the functional effects of urocortin 2 on mouse cardiomyocytes and elucidated the underlying signalling pathways and mechanisms. EXPERIMENTAL APPROACH: Mouse ventricular myocytes were field-stimulated at 0.5 Hz at room temperature. Fractional shortening and [Ca²(+)](i) transients were measured by an edge detection and epifluorescence system respectively. Western blots were carried out on myocyte extracts with antibodies against total phospholamban (PLN) and PLN phosphorylated at serine-16. KEY RESULTS: Urocortin 2 elicited time- and concentration-dependent positive inotropic and lusitropic effects (EC50 : 19 nM) that were abolished by antisauvagine-30 (10 nM, n= 6), a specific antagonist of corticotrophin releasing factor (CRF) CRF2 receptors. Urocortin 2 (100 nM) increased the amplitude and decreased the time constant of decay of the underlying [Ca²(+)](i) transients. Urocortin 2 also increased PLN phosphorylation at serine-16. H89 (2 µM) or KT5720 (1 µM), two inhibitors of protein kinase A (PKA), as well as KN93 (1 µM), an inhibitor of Ca²(+)/calmodulin-dependent protein kinase II (CaMKII), suppressed the urocortin 2 effects on shortening and [Ca²(+)](i) transients. In addition, urocortin 2 also elicited arrhythmogenic events consisting of extra cell shortenings and extra [Ca²(+)](i) increases in diastole. Urocortin 2-induced arrhythmogenic events were significantly reduced in cells pretreated with KT5720 or KN93. CONCLUSIONS AND IMPLICATIONS: Urocortin 2 enhanced contractility in mouse ventricular myocytes via activation of CRF2 receptors in a cAMP/PKA- and Ca²(+)/CaMKII-dependent manner. This enhancement was accompanied by Ca²(+)-dependent arrhythmogenic effects mediated by PKA and CaMKII.