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Dronedarone reduced the incidence of hospitalization due to cardiovascular events or death in patients with atrial fibrillation. (ClinicalTrials.gov number, NCT00174785.)

AimsAlthough non-vitamin K antagonist oral anticoagulants are recommended for stroke prevention in patients with non-valvular atrial fibrillation (NVAF) based on clinical trial results, there is a need for safety and efficacy data from unselected patients in everyday clinical practice. XANTUS investigated the safety and efficacy of the Factor Xa inhibitor rivaroxaban in routine clinical use in the NVAF setting.Methods and resultsConsecutive consenting patients with NVAF newly started on rivaroxaban were eligible and were followed up at ∼3-month intervals for 1 year, or for at least 30 days after permanent discontinuation. All adverse events (AEs) were recorded as AEs or serious AEs; major outcomes (including major bleeding, symptomatic thromboembolic events [stroke, systemic embolism, transient ischaemic attack, and myocardial infarction], and all-cause death) were centrally adjudicated. There were 6784 patients treated with rivaroxaban at 311 centres in Europe, Israel, and Canada. Mean patient age was 71.5 years (range 19–99), 41% were female, and 9.4% had documented severe or moderate renal impairment (creatinine clearance <50 mL/min). The mean CHADS2 and CHA2DS2-VASc scores were 2.0 and 3.4, respectively; 859 (12.7%) patients had a CHA2DS2-VASc score of 0 or 1. The mean treatment duration was 329 days. Treatment-emergent major bleeding occurred in 128 patients (2.1 events per 100 patient-years), 118 (1.9 events per 100 patient-years) died, and 43 (0.7 events per 100 patient-years) suffered a stroke.ConclusionXANTUS is the first international, prospective, observational study to describe the use of rivaroxaban in a broad NVAF patient population. Rates of stroke and major bleeding were low in patients receiving rivaroxaban in routine clinical practice.Trial registration numberClinicaltrials.gov: NCT01606995.

BackgroundLimited data are available on the characteristics, clinical management, and outcomes of patients with atrial fibrillation at risk of stroke, from a worldwide perspective. The aim of this study was to describe the baseline characteristics and initial therapeutic management of patients with non-valvular atrial fibrillation across the spectrum of sites at which these patients are treated.Methods and FindingsThe Global Anticoagulant Registry in the FIELD (GARFIELD) is an observational study of patients newly diagnosed with non-valvular atrial fibrillation. Enrollment into Cohort 1 (of 5) took place between December 2009 and October 2011 at 540 sites in 19 countries in Europe, Asia-Pacific, Central/South America, and Canada. Investigator sites are representative of the distribution of atrial fibrillation care settings in each country. Cohort 1 comprised 10,614 adults (≥18 years) diagnosed with non-valvular atrial fibrillation within the previous 6 weeks, with ≥1 investigator-defined stroke risk factor (not limited to those in existing risk-stratification schemes), and regardless of therapy. Data collected at baseline included demographics, medical history, care setting, nature of atrial fibrillation, and treatments initiated at diagnosis. The mean (SD) age of the population was 70.2 (11.2) years; 43.2% were women. Mean±SD CHADS2 score was 1.9±1.2, and 57.2% had a score ≥2. Mean CHA2DS2-VASc score was 3.2±1.6, and 8,957 (84.4%) had a score ≥2. Overall, 38.0% of patients with a CHADS2 score ≥2 did not receive anticoagulant therapy, whereas 42.5% of those at low risk (score 0) received anticoagulant therapy.ConclusionsThese contemporary observational worldwide data on non-valvular atrial fibrillation, collected at the end of the vitamin K antagonist-only era, indicate that these drugs are frequently not being used according to stroke risk scores and guidelines, with overuse in patients at low risk and underuse in those at high risk of stroke.Trial RegistrationClinicalTrials.gov TRI08888

NCT01674647.

Estrogen and insulin-like-growth factor 1 (IGF-1) are potent mitogenic stimuli that share important properties in the control of cellular proliferation. However, the coupling between the signaling cascades of estrogen receptors ␣ and ␤ and the IGF-1 receptor (IGF-1R) is poorly understood. Therefore, we selectively transfected estrogen receptor ␣ or ␤ in COS7 and HEK293 cells, which contain IGF-1R. In presence of estrogen receptor ␣ but not ␤, 17␤-estradiol (E2) rapidly induces phosphorylation of the IGF-1R and the extracellular signal-regulated kinases 1/2. Furthermore, upon stimulation with E2, estrogen receptor ␣ but not ␤ bound rapidly to the IGF-1R in COS7 as well as L6 cells, which express all investigated receptors endogenously. Control experiments in the IGF-1R-deficient fibroblast cell line R ؊ showed that after stimulation with E2 only estrogen receptor ␣ bound to the transfected IGF-1R. Overexpression of dominant negative mitogen-activated protein kinases kinase inhibited this effect. Finally, estrogen receptor ␣ but not ␤ is required to induce the activation of the estrogen receptor-responsive reporter ERE-LUC in IGF-1-stimulated cells. Taken together, these data demonstrate that ligand bound estrogen receptor ␣ is required for rapid activation of the IGF-1R signaling cascade.Estrogen as well as insulin-like growth factor 1 (IGF-1) 1 are potent mitogens that are involved in a large array of processes that control proliferation and differentiation in mammalian cells (1, 2). Both mitogens act through receptor-mediated signaling pathways. The cross-talk between these two signaling pathways is currently under investigation (3-6). Estrogen is a steroid hormone that binds to members of the nuclear receptor superfamily (7), whereas IGF-1 as a peptide-growth factor binds to a transmembrane tyrosine kinase receptor, which signals via a series of phosphorylation events (2).Two different estrogen receptors, ER␣ and ER␤, which are encoded by genes located on different chromosomes, have been identified so far (8,9). Sequence analysis demonstrates a high degree of homology between ER␣ and ER␤ in the DNA-binding domain and the ligand-binding domain. However, there are significant differences in regions that would be expected to influence transcriptional activity. The ability of estrogen receptors to activate target gene transcription has been attributed to two regions: the N-terminal activation function 1 (AF-1) and the ligand-dependent AF-2, which is localized in the C-terminal hormone-binding domain (10, 11). AF-1 and AF-2 can activate transcription independently and synergistically, and they act in a promoter-and cell-specific manner (12, 13). Phosphorylation of a serine residue at position 118 is required for full action of the AF-1 (14). Both AF-1 and AF-2 are required to enhance transcription of target genes through AP-1 sites (15). Interestingly, ER␣ and ER␤ act differently at AP-1 sites (16), which may be due to differences in their AF domains (17). ER␣ and ER␤ can form homo-and heterodimers (18), and thus t...

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Background-Cardiac hypertrophy is an independent risk factor for cardiovascular morbidity and mortality in men and in women. Epidemiological studies indicate that estrogen replacement therapy is cardioprotective; the mechanisms involved in this process, however, are poorly understood. We therefore studied the effect of 17␤-estradiol (E 2 ) on the development of pressure-overload hypertrophy. Methods and Results-Ovariectomized mice receiving E 2 or placebo underwent transverse aortic constriction (TAC) or sham operation. TAC led to a significant increase in ventricular mass compared with sham operation. E 2 treatment reduced cardiac hypertrophy by 31% and 26% compared with placebo 4 and 8 weeks after TAC, whereas it had no effect on the degree of pressure overload, as determined by hemodynamic measurements. Furthermore, E 2 blocked the increased phosphorylation of p38-mitogen-activated protein kinase (MAPK) observed in the placebo-treated animals with TAC. No differences were observed in the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) 1/2 between the groups. E 2 had no effect on the expression of angiotensin-converting enzyme (ACE) or the angiotensin II type 1 receptor. Ventricular atrial natriuretic peptide (ANP) expression was detected only in the animals with TAC. Compared with placebo, E 2 treatment led to an increased expression of ANP in animals with pressure overload. Conclusions-Here, we show that E 2 attenuates the hypertrophic response to pressure overload in mice. This observation demonstrates that hormone replacement therapy with E 2 has direct effects on the heart and may be beneficial in the treatment of postmenopausal women to reduce cardiac hypertrophy. Key Words: hormones Ⅲ hypertrophy Ⅲ myocardium Ⅲ sex T he increase of left ventricular mass represents the structural mechanism of adaptation of the heart in response to pressure overload. The resulting left ventricular hypertrophy is an important negative predictor of cardiac morbidity and mortality and displays significant sex-based differences. 1,2 Estrogen is known to have multiple protective effects on the cardiovascular system. 3 The role of estrogen in the development of cardiac hypertrophy, however, is poorly understood. See p 1333We have shown previously that cardiac myocytes and cardiac fibroblasts contain both known estrogen receptor isoforms, called ␣ and ␤. 4 Via these receptors, estrogen can regulate the cardiac expression of endothelial and inducible NO synthase and connexin 43. 5 Estrogen also modulates the activity of the mitogen-activated protein kinase (MAPK) pathways in cardiac myocytes. 6 The MAPK signaling pathways consist of a sequence of successively acting kinases that ultimately result in the dual phosphorylation and activation of effector kinases such as p38-MAPKs, c-Jun N-terminal kinases (JNKs), and extracellular signal-regulated kinases (ERKs), which subsequently phosphorylate a large array of targets, leading to altered gene expression patterns. 7 These signalin...