Global transcriptome analysis of murine embryonic stem cell-derived cardiomyocytes

Microarray analysis reveals that the specific pattern of gene expression in cardiomyocytes derived from embryonic stem cells reflects the biological, physiological and functional processes occurring in mature cardiomyocytes

Baroreflex Activation Therapy for the Treatment of Heart Failure With a Reduced Ejection Fraction

AbstractObjectivesThe objective of this clinical trial was to assess the safety and efficacy of carotid BAT in advanced HF.BackgroundIncreased sympathetic and decreased parasympathetic activity contribute to heart failure (HF) symptoms and disease progression. Baroreflex activation therapy (BAT) results in centrally mediated reduction of sympathetic outflow and increased parasympathetic activity.MethodsPatients with New York Heart Association (NYHA) functional class III HF and ejection fractions ≤35% on chronic stable guideline-directed medical therapy (GDMT) were enrolled at 45 centers in the United States, Canada, and Europe. They were randomly assigned to receive ongoing GDMT alone (control group) or ongoing GDMT plus BAT (treatment group) for 6 months. The primary safety end point was system- and procedure-related major adverse neurological and cardiovascular events. The primary efficacy end points were changes in NYHA functional class, quality-of-life score, and 6-minute hall walk distance.ResultsOne hundred forty-six patients were randomized, 70 to control and 76 to treatment. The major adverse neurological and cardiovascular event–free rate was 97.2% (lower 95% confidence bound 91.4%). Patients assigned to BAT, compared with control group patients, experienced improvements in the distance walked in 6 min (59.6 ± 14 m vs. 1.5 ± 13.2 m; p = 0.004), quality-of-life score (–17.4 ± 2.8 points vs. 2.1 ± 3.1 points; p < 0.001), and NYHA functional class ranking (p = 0.002 for change in distribution). BAT significantly reduced N-terminal pro–brain natriuretic peptide (p = 0.02) and was associated with a trend toward fewer days hospitalized for HF (p = 0.08).ConclusionsBAT is safe and improves functional status, quality of life, exercise capacity, N-terminal pro–brain natriuretic peptide, and possibly the burden of heart failure hospitalizations in patients with GDMT-treated NYHA functional class III HF. (Barostim Neo System in the Treatment of Heart Failure; NCT01471860; Barostim HOPE4HF [Hope for Heart Failure] Study; NCT01720160

Murine Short Axis Ventricular Heart Slices for Electrophysiological Studies

Murine cardiomyocytes have been extensively used for in vitro studies of cardiac physiology and new therapeutic strategies. However, multicellular preparations of dissociated cardiomyocytes are not representative of the complex in vivo structure of cardiomyocytes, non-myocytes and extracellular matrix, which influences both mechanical and electrophysiological properties of the heart. Here we describe a technique to prepare viable ventricular slices of adult mouse hearts with a preserved in vivo like tissue structure, and demonstrate their suitability for electrophysiological recordings. After excision of the heart, ventricles are separated from the atria, perfused with Ca2+-free solution containing 2,3-butanedione monoxime and embedded in a 4% low-melt agarose block. The block is placed on a microtome with a vibrating blade, and tissue slices with a thickness of 150-400 mu m are prepared keeping the vibration frequency of the blade at 60-70 Hz and moving the blade forward as slowly as possible. Thickness of the slices depends on the further application. Slices are stored in ice cold Tyrode's solution with 0.9 mM Ca2+ and 2,3-butanedione monoxime (BDM) for 30 min. Afterwards, slices are transferred to 37 degrees C DMEM for 30 min to wash out the BDM. Slices can be used for electrophysiological studies with sharp electrodes or micro electrode arrays, for force measurements to analyze contractile function or to investigate the interaction of transplanted stem cell-derived cardiomyocytes and host tissue. For sharp electrode recordings, a slice is placed into a 3 cm cell culture dish on the heating plate of an inverted microscope. The slice is stimulated with a unipolar electrode, and intracellular action potentials of cardiomyocytes within the slice are recorded with a sharp glass electrode

Induced pluripotent stem cells as cardiac arrhythmic in vitro models and the impact for drug discovery

Introduction: The development of new antiarrhythmic agents is challenging and is hampered by high attrition rate of novel drug candidates. One of the reasons for this is limited predictability of existing preclinical models for drug assessment. Cardiomyocytes (CMs) derived from disease-specific induced pluripotent stem cells (iPSC) represent a novel in vitro cellular model of cardiac arrhythmias with an unprecedented potential for generating new mechanistic insight into disease pathophysiology and improving the process of drug development. Areas covered: This review outlines recent studies demonstrating the suitability and limitations of iPSC-derived CMs (iPS-CMs) for in vitro modeling inherited arrhythmias and drug testing. The authors focus on channelopathies and outline the properties of iPS-CMs, highlighting their utility and limitations for investigating the mechanism of cardiac arrhythmias and drug discovery. Expert opinion: The iPS-CMs represent a valuable addition to the already existing armamentarium of cardiac arrhythmic models. However, the superiority of iPS-CMs over other arrhythmia models has not yet been rigorously established and the limitations of the model must be overcome before its full potential for antiarrhythmic drug discovery can be realized. Nevertheless, iPS cell-based platforms hold a great potential for increasing our knowledge about cellular arrhythmia mechanisms and improving the drug discovery process

Arterial hypertension-What was important in 2020?

Arterial hypertension remains the most significant risk factor for cardiovascular disease and associated disability worldwide. In the field of arterial hypertension the coronavirus disease 2019 (COVID-19) pandemic also determined major parts of the scientific debate. Arterial hypertension is associated with a severe course of COVID-19, whereas risk of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) does not appear to be increased in hypertensive individuals. According to current data, treatment with angiotensin-converting enzyme (ACE) inhibitors and angiotensin type 1 receptor blockers is not associated with an increased risk of SARS-CoV-2 infection or with a more severe course of COVID-19. A study on antihypertensive chronotherapy determined the scientific discourse on the medication treatment of hypertension. The HYGIA study concluded that bedtime medication reduces the cardiovascular risk in patients with arterial hypertension. Due to some study limitations, routine administration of bedtime antihypertensive medication cannot be recommended. Some of the reasons are discussed herein. Another scientific focus was on new renal denervation studies. Here, one can summarize that according to novel evidence, catheter-based renal denervation is an effective and safe procedure for the treatment of arterial hypertension, which could become established as an alternative to pharmaceutical blood pressure reduction in the near future

Improvement of Left Ventricular Ejection Fraction by Baroreflex Activation Therapy in a Young Man with Dilated Cardiomyopathy

The progression of heart failure with reduced ejection fraction is promoted by sympathovagal imbalance. Baroreflex activation therapy (BAT) by the electrical stimulation of baroreceptors at the carotid sinus significantly improved exercise capacity and NT-proBNP levels in a randomized trial; however, no significant difference in left ventricular ejection fraction (LV-EF) between groups was found. Here, we report the case of a 30-year-old man with a long history of dilated cardiomyopathy and severely reduced LV-EF despite optimal medical therapy, who was treated with BAT since October 2014 and showed a remarkable improvement in both symptoms and LV-EF under this treatment