171 research outputs found
Cardiomyocyte stiffness in diastolic heart failure
Background - Heart failure with preserved left ventricular (LV) ejection fraction (EF) is increasingly recognized and usually referred to as diastolic heart failure (DHF). Its pathogenetic mechanism remains unclear, partly because of a lack of myocardial biopsy material. Endomyocardial biopsy samples obtained from DHF patients were therefore analyzed for collagen volume fraction (CVF) and sarcomeric protein composition and compared with control samples. Single cardiomyocytes were isolated from these biopsy samples to assess cellular contractile performance. Methods and Results - DHF patients (n=12) had an LVEF of 71 ± 11%, an LV end-diastolic pressure (LVEDP) of 28±4 mm Hg, and no significant coronary artery stenoses. DHF patients had higher CVFs (7.5±4.0%, P<0.05) than did controls (n=8, 3.8±2.0%), and no conspicuous changes in sarcomeric protein composition were detected, Cardiomyocytes, mechanically isolated and treated with Triton X-100 to remove all membranes, were stretched to a sarcomere length of 2.2 Όm and activated with solutions containing varying [Ca2+]. Compared with cardiomyocytes of controls, cardiomyocytes of DHF patients developed a similar total isometric force at maximal [Ca2+], but their resting tension (Fpassive) in the absence of Ca2+ was almost twice as high (6.6±3.0 versus 3.5±1.7 kN/m2, P<0.001). F passive and CVF combined yielded stronger correlations with LVEDP than did either alone. Administration of protein kinase A (PKA) to DHF cardiomyocytes lowered Fpassive to control values. Conclusions - DHF patients had stiffer cardiomyocytes, as evident from a higher F passive, at the same sarcomere length. Together with CVF, F passive determined in vivo diastolic LV dysfunction. Correction of this high Fpassive by PKA suggests that reduced phosphorylation of sarcomeric proteins is involved in DHF
ERK1 as a therapeutic target for dendritic cell vaccination against high-grade gliomas
Glioma regression requires the recruitment of potent anti-tumor immune cells into the tumor microenvironment. Dendritic cells (DCs) play a role in immune responses to these tumors. The fact that DC vaccines do not effectively combat high-grade gliomas, however, suggests that DCs need to be genetically modified especially to promote their migration to tumor relevant sites. Previously, we identified extracellular signal-regulated kinase (ERK1) as a regulator of DC immunogenicity and brain autoimmunity. In the present study, we made use of modern magnetic resonance methods to study the role of ERK1 in regulating DC migration and tumor progression in a model of high-grade glioma. We found that ERK1-deficient mice are more resistant to the development of gliomas, and tumor growth in these mice is accompanied by a higher infiltration of leukocytes. ERK1-deficient DCs exhibit an increase in migration that is associated with sustained Cdc42 activation and increased expression of actin-associated cytoskeleton-organizing proteins. We also demonstrated that ERK1 deletion potentiates DC vaccination and provides a survival advantage in high-grade gliomas. Considering the therapeutic significance of these results, we propose ERK1-deleted DC vaccines as an additional means of eradicating resilient tumor cells and preventing tumor recurrence
Hypophosphorylation of the stiff N2B Titin isoform raises cardiomyocyte resting tension in failing human myocardium
Spontaneous migraine attack causes alterations in default mode network connectivity
BACKGROUND:
Although migraine is one of the most investigated neurologic disorders, we do not have a perfect neuroimaging biomarker for its pathophysiology. One option to improve our knowledge is to study resting-state functional connectivity in and out of headache pain. However, our understanding of the functional connectivity changes during spontaneous migraine attack is partial and incomplete.
CASE PRESENTATION:
Using resting-state functional magnetic resonance imaging we assessed a 24-year old woman affected by migraine without aura at two different times: during a spontaneous migraine attack and in interictal phase. Seed-to-voxel whole brain analysis was carried out using the posterior cingulate cortex as a seed, representing the default mode network (DMN). Our results showed decreased intrinsic connectivity within core regions of the DMN with an exception of a subsystem including the dorsal medial and superior frontal gyri, and the mid-temporal gyrus which is responsible for pain interpretation and control. In addition, increased connectivity between the DMN and pain and specific migraine-related areas, such as the pons and hypothalamus, developed during the spontaneous migraine attack.
CONCLUSION:
Our preliminary results provide further support for the hypothesis that alterations of the DMN functional connectivity during migraine headache may lead to maladaptive top-down modulation of migraine pain-related areas which might be a specific biomarker for migraine
Outcome comparison of 600- and 300-mg loading doses of clopidogrel in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: results from the ARMYDA-6 MI (Antiplatelet therapy for Reduction of MYocardial Damage during Angioplasty-Myocardial Infarction) randomized study.
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
SzĂvinfarktus miatt kezelt betegek korai Ă©s kĂ©sĆi prognĂłzisa. Magyar Infarctus Regiszter VizsgĂĄlat
Introduction: Mortality data of patients with acute myocardial infarction are incomplete in Hungary. Aim: The aim of the authors was to analyse the data of 8582 myocardial infarction patients (4981 with ST-elevation myocardial infarction) registered in the Hungarian Myocardial Infarction Register in order to define the hospital, 30-day, and 1-year mortality. To evaluate the prehospital mortality of myocardial infarction, all myocardial infarction and sudden death were registered in five districts of Budapest. Method: Multivariate logistic regression was performed to define risk factors of mortality and the model were assessed using c statistics. Results: The hospital, 30-day and 1-year mortality of patients with ST elevation myocardial infarction were 3.7%, 9.5% and 16.5%, respectively. In patients without ST elevation myocardial infarction these figures were 4%, 9.8% and 21.7%, respectively. The 1-year mortality of patients without ST elevation was higher than those of with ST elevation and the difference was statistically significant. Age, Killip class, diabetes mellitus, history of stroke and myocardial infarction were independent predictors of death. Coronary intervention improved the prognosis of patients with myocardial infarction significantly. Conclusions: The rate of pre-hospital mortality was considerably high; 72.5% of 30 day mortality occurred before admission to hospital. Orv. Hetil., 2013, 154, 1297-1302
Levosimendan Efficacy and Safety: 20 Years of SIMDAX in Clinical Use
Levosimendan was first approved for clinical use in 2000, when authorization was granted by Swedish regulatory authorities for the hemodynamic stabilization of patients with acutely decompensated chronic heart failure (HF). In the ensuing 20 years, this distinctive inodilator, which enhances cardiac contractility through calcium sensitization and promotes vasodilatation through the opening of adenosine triphosphate-dependent potassium channels on vascular smooth muscle cells, has been approved in more than 60 jurisdictions, including most of the countries of the European Union and Latin America. Areas of clinical application have expanded considerably and now include cardiogenic shock, takotsubo cardiomyopathy, advanced HF, right ventricular failure, pulmonary hypertension, cardiac surgery, critical care, and emergency medicine. Levosimendan is currently in active clinical evaluation in the United States. Levosimendan in IV formulation is being used as a research tool in the exploration of a wide range of cardiac and noncardiac disease states. A levosimendan oral form is at present under evaluation in the management of amyotrophic lateral sclerosis. To mark the 20 years since the advent of levosimendan in clinical use, 51 experts from 23 European countries (Austria, Belgium, Croatia, Cyprus, Czech Republic, Estonia, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Russia, Slovenia, Spain, Sweden, Switzerland, the United Kingdom, and Ukraine) contributed to this essay, which evaluates one of the relatively few drugs to have been successfully introduced into the acute HF arena in recent times and charts a possible development trajectory for the next 20 years
Cell-to-cell variability in troponin I phosphorylation in a porcine model of pacing-induced heart failure
We tested the hypothesis that myocardial contractile protein phosphorylation and the Ca2+ sensitivity of force production are dysregulated in a porcine model of pacing-induced heart failure (HF). The level of protein kinase A (PKA)-dependent cardiac troponin I (TnI) phosphorylation was lower in the myocardium surrounding the pacing electrode (pacing site) of the failing left ventricle (LV) than in the controls. Immunohistochemical assays of the LV pacing site pointed to isolated clusters of cardiomyocytes exhibiting a reduced level of phosphorylated TnI. Flow cytometry on isolated and permeabilized cardiomyocytes revealed a significantly larger cell-to-cell variation in the level of TnI phosphorylation of the LV pacing site than in the opposite region in HF or in either region in the controls: the interquartile range (IQR) on the distribution histogram of relative TnI phosphorylation was wider at the pacing site (IQRÂ =Â 0.53) than that at the remote site of HF (IQRÂ =Â 0.42; PÂ =Â 0.0047) or that of the free wall of the control animals (IQRÂ =Â 0.36; PÂ =Â 0.0093). Additionally, the Ca2+ sensitivities of isometric force production were higher and appeared to be more variable in single permeabilized cardiomyocytes from the HF pacing site than in the healthy myocardium. In conclusion, the level of PKA-dependent TnI phosphorylation and the Ca2+ sensitivity of force production exhibited a high cell-to-cell variability at the LV pacing site, possibly explaining the abnormalities of the regional myocardial contractile function in a porcine model of pacing-induced HF
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Preserved emotional awareness of pain in a patient with extensive bilateral damage to the insula, anterior cingulate, and amygdala
Functional neuroimaging investigations of pain have discovered a reliable pattern of activation within limbic regions of a putative "pain matrix" that has been theorized to reflect the affective dimension of pain. To test this theory, we evaluated the experience of pain in a rare neurological patient with extensive bilateral lesions encompassing core limbic structures of the pain matrix, including the insula, anterior cingulate, and amygdala. Despite widespread damage to these regions, the patient's expression and experience of pain was intact, and at times excessive in nature. This finding was consistent across multiple pain measures including self-report, facial expression, vocalization, withdrawal reaction, and autonomic response. These results challenge the notion of a "pain matrix" and provide direct evidence that the insula, anterior cingulate, and amygdala are not necessary for feeling the suffering inherent to pain. The patient's heightened degree of pain affect further suggests that these regions may be more important for the regulation of pain rather than providing the decisive substrate for pain's conscious experience
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