Effects of Physical Activity in the High School Curriculum on Cardiovascular Health, Cognitive and Physical Performance.

Cardiovascular health at a young age has implications for preventing cardiovascular disease, and it is associated with improved physical and cognitive performance during the aging process. Sports are well known to prevent cardiovascular disease; however, school-based interventions have mostly been neglected. This cross-sectional study aimed to compare groups of high school students, stratified by the amount of physical activity in their high school curriculum and downtime. Comparisons concerning physical and cognitive performance and arterial stiffness were made. A total of 63 senior-year students were investigated. Arterial stiffness was assessed using the oscillometric technique with ArteriographTM detection. Three-kilometer and pendulum runs were conducted as typical training loads. Cognitive performance was evaluated via the visual and verbal memory and number connection tests. Regarding cognitive skills, extracurricular physical activity improved the number connection test in male participants (p = 0.004). For physical performance, female students with a sports-focused curriculum were faster in the 3 km run (p < 0.001). Concerning arterial stiffness, the measurements yielded a lower mean arterial pressure (p = 0.015) and aortic pulse wave velocity (p = 0.04) in male students with a sports-focused curriculum. In summary, extracurricular physical activity and enrollment in a sports-focused curriculum may be associated with lower cardiovascular risk due to lower arterial stiffness and better physical and cognitive abilities.

Negative Impact of the UEFA European Soccer Championship on Central Hemodynamics and Arterial Stiffness: A Multicenter Study.

(1) Background: watching sporting events may trigger cardiovascular events by elevating emotional stress levels. The underlying reasons and specific populations at risk are not well defined. (2) Methods: we conducted a multicenter prospective trial at three German sites during the UEFA Soccer EC 2012 and 2021 comprising 52 healthy participants (noCVD) and 18 patients hospitalized with cardiovascular disease (CVD). Subjects were studied during matches of the German national team (GP) as well as corresponding matches without German participation (noGP). Peripheral and central blood pressure (BP) and parameters of arterial stiffness were measured (Mobil-O-Graph™, I.E.M., Stolberg, Germany) before, during, and after the matches. (3) Results: in terms of CVD, peripheral as well as central BP and heart rate increased significantly during GP as well as noGP matches and remained elevated beyond the end of the matches. Likewise, arterial stiffness parameters and vascular resistance were higher during the matches and remained elevated after the matches. No consistent significant differences were found between GP and noGP matches. (4) Conclusions: this is the first study on real-life changes in hemodynamics during sport-associated emotional stress, with comparison between noCVD and CVD. We found that alterations were profound in CVD and remained elevated even after the matches.

The influence of light on the beat rate variability of murine embryonic stem cell derived cardiomyocytes.

BACKGROUND: The human heart rhythm can be quantified by analyzing the heart rate variability (HRV). A major influencing factor of the HRV is the circadian rhythm. The ocular light and the hormone melatonin play decisive roles in the circadian rhythm. The beat rate variability (BRV) is considered to be the in vitro equivalent of the HRV. Previous studies have demonstrated the influence of melatonin on cardiomyocytes. Also, the influence of light on cardiomyocytes has been described before. Nevertheless, the effect of light on the BRV of cardiomyocytes has not yet been examined. MATERIAL AND METHODS: The BRV of spontaneously beating cardiomyocytes was measured with microelectrode arrays over a time period of 30 min. The experiments were either performed with light exposure (with and without an infrared filter) or in complete darkness. RESULTS: The BRV was higher and the beating frequency was lower when the cardiomyocytes were exposed to the full spectrum of light, compared to the measurements in darkness as well as to the measurements with an infrared filter. In contrast, the differences of BRV between the measurements in darkness and the measurements with an infrared filter were not as distinct. CONCLUSIONS: This is the first study demonstrating the influence of light on the beating rhythm of heart tissue in vitro. The results indicate that especially the infrared spectrum of light alters the BRV. These findings could be of interest for clinical applications such as the field of optical pacing as well as in neonatal patient care.

Modeling genetic cardiac channelopathies using induced pluripotent stem cells - Status quo from an electrophysiological perspective.

Long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ventricular tachycardia (CPVT) are genetic diseases of the heart caused by mutations in specific cardiac ion channels and are characterized by paroxysmal arrhythmias, which can deteriorate into ventricular fibrillation. In LQTS3 and BrS different mutations in the SCN5A gene lead to a gain-or a loss-of-function of the voltage-gated sodium channel Nav1.5, respectively. Although sharing the same gene mutation, these syndromes are characterized by different clinical manifestations and functional perturbations and in some cases even present an overlapping clinical phenotype. Several studies have shown that Na+ current abnormalities in LQTS3 and BrS can also cause Ca2+-signaling aberrancies in cardiomyocytes (CMs). Abnormal Ca2+ homeostasis is also the main feature of CPVT which is mostly caused by heterozygous mutations in the RyR2 gene. Large numbers of disease-causing mutations were identified in RyR2 and SCN5A but it is not clear how different variants in the SCN5A gene produce different clinical syndromes and if in CPVT Ca2+ abnormalities and drug sensitivities vary depending on the mutation site in the RyR2. These questions can now be addressed by using patient-specific in vitro models of these diseases based on induced pluripotent stem cells (iPSCs). In this review, we summarize different insights gained from these models with a focus on electrophysiological perturbations caused by different ion channel mutations and discuss how will this knowledge help develop better stratification and more efficient personalized therapies for these patients.

The influence of melatonin on the heart rhythm - An in vitro simulation with murine embryonic stem cell derived cardiomyocytes.

BACKGROUND: In healthy individuals, a major factor influencing the heart rate variability (HRV) is the circadian rhythm. The role of melatonin as an essential component of the circadian rhythm in the adult human organism and the beneficial effects of a treatment with melatonin during the fetal period is well described. Toxic effects of melatonin are discussed less frequently. Since pharmacological studies cannot be carried out on pregnant women, the establishment of an equivalent in vitro model is important. We therefore tested whether melatonin can influence the beat rate variability (BRV) of spontaneously beating cardiomyocytes derived from murine embryonic stem cells (mESCs) and whether melatonin exhibits toxic effects in this in vitro model. METHODS: Microelectrode Arrays recorded extracellular field potentials of spontaneously beating cardiomyocytes. Melatonin was applied in a concentration range from 10-11 M to 10-5 M. The analysis of the BRV focused on time domain methods. RESULTS: In line with clinical observations, melatonin decreased the beating frequency and increased the BRV. The effect of melatonin up to a concentration of 10-6 M was reversible, whereas the application of higher concentrations induced an irreversible effect. CONCLUSION: The study underlines the potential of this in vitro model to help explore the development of circadian rhythms and their modulation by melatonin in the embryonic phase. The results imply that melatonin influences the heart rhythm as early as during the embryonic heart development. Furthermore, the results indicate a potentially toxic effect of melatonin that has not been described in detail before.

The Effect of Antiarrhythmic Drugs on the Beat Rate Variability of Human Embryonic and Human Induced Pluripotent Stem Cell Derived Cardiomyocytes.

Embryonic stem cell (ESC) derived tissue is a promising tool to be used in different clinical, preclinical and also scientific settings, for example as in vivo biological pacemaker, preclinical drug safety screening tool or ultimately as part of a cell replacement therapy. However, before ESC derived tissue can be used routinely for these purposes in humans, further studies are needed. In this context, the aims of the present study were to examine the effect of antiarrhythmic drugs on human ESC (hESC) und human induced pluripotent stem cell (hiPSC) derived cardiomyocytes by analyzing the beat rate variability (BRV), which can be considered as the in vitro equivalent of the heart rate variability (HRV) in vivo. Short-term recordings of extracellular field potentials of spontaneously beating cardiomyocytes derived from hESCs and hiPSCs were made using Microelectrode Arrays (MEA). The effect of Flecainide, Ivabradine and Metoprolol was tested. The offline analysis of the BRV was mainly focused on time domain methods. Additionally a non-linear analysis method was used. The evaluation of the Poincaré-Plots of the measurements without pharmacological intervention revealed that the vast majority of the scatter plots have a similar, ellipsoid shape. Flecainide and Ivabradine influenced BRV parameters significantly, whereas Metoprolol did not alter the BRV markedly. We detected remarkable similarities between the BRV of hESC and hiPSC derived cardiomyocytes in vitro and the HRV in vivo. The effect of antiarrhythmic drugs on spontaneously beating cardiomyocytes derived from hESC and hiPSC was generally consistent with clinical experiences and also with our previous study based on murine ESC derived cardiomyocytes. In conclusion, our study points out the great potential of hESC and hiPSC derived tissue to be used routinely for many different applications in medicine and science.

Frequency of atrial thrombus formation in patients with atrial fibrillation under treatment with non-vitamin K oral anticoagulants in comparison to vitamin K antagonists: a systematic review and meta-analysis.

BACKGROUND: To assess the frequency of left atrium/left atrial appendage (LA/LAA) thrombus under treatment with non-vitamin K oral anticoagulants (NOACs) in comparison with vitamin K antagonists (VKAs) in patients with non-valvular atrial fibrillation (AF). METHODS: PubMed, Web of Science™, EMBASE and the Cochrane Library databases were searched for studies comparing NOACs with VKAs in AF patients who underwent diagnostic transoesophageal echocardiography (TEE). RESULTS: A total of four trials were considered eligible and were included in the meta-analysis. Four RCTs comprising n = 2397 AF patients (NOACs: n = 1412, VKAs: n = 985) were included in the meta-analysis. The frequency of LA/LAA thrombus formation under treatment with NOACs was similar to VKAs [odds ratio (OR) 1.14, 95% confidence intervals (95% CIs) 0.97-1.65, p = 0.48]. Both treatment groups revealed an approximately 5% frequency of thrombus formation, although a precise calculation is not possible due to Simpson paradox. Indications of heterogeneity between the included trials were not found (χ2 test p = 0.99, I2 = 0%). CONCLUSIONS: The findings of this meta-analysis suggest that NOACs are similar to VKAs regarding the frequency of LA/LAA thrombus in patients with AF. An unknown number of patients in the original studies did not receive sufficient anticoagulation for at least 3 weeks prior to TEE examination, and therefore the present results should be interpreted with caution. Systematic review registration- http://www.crd.york.ac.uk/PROSPERO . Unique identifier: PROSPERO CRD42017059293.

E-cigarettes and cigarettes worsen peripheral and central hemodynamics as well as arterial stiffness: A randomized, double-blinded pilot study.

The introduction of electronic cigarettes has led to widespread discussion on the cardiovascular risks compared to conventional smoking. We therefore conducted a randomized cross-over study of the acute use of three tobacco products, including a control group using a nicotine-free liquid. Fifteen active smokers were studied during and after smoking either a cigarette or an electronic cigarette with or without nicotine (eGo-T CE4 vaporizer). Subjects were blinded to the nicotine content of the electronic cigarette and were followed up for 2 hours after smoking a cigarette or vaping an electronic cigarette. Peripheral and central blood pressures as well as parameters of arterial stiffness were measured by a Mobil-O-Graph® device. The peripheral systolic blood pressure rose significantly for approximately 45 minutes after vaping nicotine-containing liquid ( p<0.05) and for approximately 15 minutes after smoking a conventional cigarette ( p<0.01), whereas nicotine-free liquids did not lead to significant changes during the first hour of follow-up. Likewise, heart rate remained elevated approximately 45 minutes after vaping an electronic cigarette with nicotine-containing liquid and over the first 30 minutes after smoking a cigarette in contrast to controls. Elevation of pulse wave velocity was independent from mean arterial pressure as well as heart rate in the electronic cigarette and cigarette groups. In this first of its kind trial, we observed changes in peripheral and central blood pressure and also in pulse wave velocity after smoking a cigarette as well as after vaping a nicotine-containing electronic cigarette. These findings may be associated with an increased long-term cardiovascular risk.

Renal denervation improves 24-hour central and peripheral blood pressures, arterial stiffness, and peripheral resistance.

Ambulatory blood pressure (BP) and central BP are better predictors for overall cardiovascular risk and mortality than brachial BP. Renal denervation (RDN) has been shown to reduce office brachial and central BP as well as brachial ambulatory BP, but data on central ambulatory BP are limited. Patients (N = 94) with treatment resistant hypertension (TRH) who underwent RDN were included. Ambulatory BP, including central pressures, hemodynamics, and arterial stiffness were measured at baseline and 3, 6, 12 months after RDN by an oscillometric device (MobiloGraph™ ). At 3, 6, and 12-month follow-ups, brachial ambulatory BP was reduced (P for all < .001). Consistently, central ambulatory BP was reduced (P for all < .001). Ambulatory assessed averaged daytime pulse wave velocity improved after RDN (P < .05). Total vascular resistance decreased (P for all < .01). In patients with TRH, RDN improves brachial and central ambulatory BP, arterial stiffness, and total vascular resistance, indicating an improvement of cardiovascular outcome.

Pacsin 2 is required for the maintenance of a normal cardiac function in the developing mouse heart.

The Pacsin proteins (Pacsin 1, 2 and 3) play an important role in intracellular trafficking and thereby signal transduction in many cells types. This study was designed to examine the role of Pacsin 2 in cardiac development and function. We investigated the development and electrophysiological properties of Pacsin 2 knockout (P2KO) hearts and single cardiomyocytes isolated from 11.5 and 15.5days old fetal mice. Immunofluorescence experiments confirmed the lack of Pacsin 2 protein expression in P2KO cardiac myocytes in comparison to wildtype (WT). Western blotting demonstrates low expression levels of connexin 43 and T-box 3 proteins in P2KO compared to wildtype (WT). Electrophysiology measurements including online Multi-Electrode Array (MEA) based field potential (FP) recordings on isolated whole heart of P2KO mice showed a prolonged AV-conduction time. Patch clamp measurements of P2KO cardiomyocytes revealed differences in action potential (AP) parameters and decreased pacemaker funny channel (If), as well as L-type Ca2+ channel (ICaL), and sodium channel (INa). These findings demonstrate that Pacsin 2 is necessary for cardiac development and function in mouse embryos, which will enhance our knowledge to better understand the genesis of cardiovascular diseases.

Inferior vena cava diameter in acute decompensated heart failure as predictor of all-cause mortality.

Inferior vena cava (IVC) diameter can be used to approximate right atrial pressure in patients admitted for acute decompensated heart failure (ADHF). Recent studies linked IVC dilation to an increased risk of early re-admission and short-term mortality. Moreover, renal insufficiency (RI) is an established risk factor for mortality in ADHF and is associated with congestion. We hypothesized that the IVC diameter is a marker of all-cause mortality but its prognostic impact may be influenced by kidney function. We analyzed data of 1101 patients admitted for ADHF with available echocardiography of the IVC by chart review and death registry linkage. Patients were dichotomized according to a cut-off value of 21 mm. Cox proportional hazards model was used to identify mortality predictors. A dilated IVC was detected in 474 (43.1%) patients. Overall, 400 (36.3%) patients died within 3 years. All-cause mortality was significantly higher in patients with dilated IVC [hazard ratio 1.45 (confidence interval 1.21-1.74); p < 0.001]. However, a dilated IVC was only associated with all-cause mortality in patients with RI function [hazard ratio 1.60 (confidence interval 1.26-2.03); p < 0.001] but not in patients with a preserved kidney function [hazard ratio 1.04 (confidence interval 0.72-1.50); P = 0.84]. IVC diameter was identified as an independent predictor for all-cause mortality in a Cox proportional hazards model with a significant interaction between IVC diameter and baseline kidney function. In conclusion, IVC dilation is a marker of high mortality risk in patients admitted for ADHF. However, this observation was confined to patients with RI.

Central hemodynamics and arterial stiffness in idiopathic and multiple system atrophy.

Blood pressure is commonly abnormal in parkinsonian disorders, but central hemodynamics and arterial stiffness, well-established predictors of total cardiovascular risk, have rarely been studied in these disorders. 32 patients [27 with idiopathic Parkinson's disease (iPD); 5 with multiple system atrophy (MSA)] and 15 controls matched for cardiac risk factors underwent 24 h-ambulatory blood pressure recordings using an I.E.M. device (Mobil-O-Graph™), measuring peripheral pressure and calculating central pressures and arterial stiffness. Mean augmentation indices corrected for heart rate (AIx@75) were significantly lower and pulse wave velocities were significantly elevated in patients compared to controls. Central systolic blood pressure, cardiac output and daytime total vascular resistance were significantly elevated in patients. Mean nocturnal systolic peripheral blood pressure and nocturnal heart rates were also significantly higher; 56.3% of patients had nocturnal hypertension (80% of the MSA group); 85.2% showed non-dipping. This supports previous findings of reduced vulnerability to systemic atherosclerosis and end-organ damage in treated PD. Yet, hemodynamic abnormalities were common and often remained asymptomatic.

Incidence of left atrial abnormalities under treatment with dabigatran, rivaroxaban, and vitamin K antagonists.

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran or rivaroxaban are alternatives to vitamin K antagonists (VKAs) for prevention of stroke and systemic embolism in patients with atrial fibrillation (AF) and atrial flutter (AFL). Incidences of risk factors for left atrium (LA) and left atrial appendage (LAA) thrombus formation, such as dense spontaneous echo contrast (SEC), low LAA velocity (LAAV) <20 cm/s under treatment with dabigatran and rivaroxaban in comparison with VKAs are unknown. METHODS: We studied 306 patients with AF (94 %) and AFL (6 %) undergoing transesophageal echocardiography. Patients received VKAs (n = 138), dabigatran (n = 68), or rivaroxaban (n = 100) for at least 3 weeks prior to investigation. Time in therapeutic range was 67 % for VKA. Mean CHADS2 score and CHA2DS2-VASc score were 1.3 and 2.5, respectively. Left atrial abnormality was defined as either dense SEC, low LAAV <20 cm/s, or thrombus. RESULTS: Any LA abnormality occurred in 9, 3, and 5 % of patients receiving VKA, dabigatran, and rivaroxaban, respectively. The most frequent abnormality was LAA thrombus (VKA: 4 %, dabigatran: 0 %, rivaroxaban: 2 %) and low LAAV of less than 20 cm/s (VKA: 4 %, dabigatran: 1 %, rivaroxaban: 1 %), followed by dense SEC (VKA: 2 %, dabigatran: 1 %, rivaroxaban: 2 %). Results of uni- and multivariate analyses revealed a numerically lower but not significantly different frequency of any LA abnormality under dabigatran (OR 0.4, 95 % Cl 0.08 - 1.88, p = 0.25) and rivaroxaban (OR 0.65, 95 % Cl 0.22 - 1.98, p = 0.45) compared to VKA. CONCLUSION: With respect to the incidence of LA abnormalities, dabigatran and rivaroxaban are not inferior to VKA.

Beat Rate Variability in Murine Embryonic Stem Cell-Derived Cardiomyocytes: Effect of Antiarrhythmic Drugs.

BACKGROUND/AIMS: Heart rate variability (HRV) refers to the fluctuation of the time interval between consecutive heartbeats in humans. It has recently been discovered that cardiomyocytes derived from human embryonic and induced pluripotent stem cells show beat rate variability (BRV) that is similar to the HRV in humans. In the present study, clinical aspects of HRV were transferred to an in vitro model. The aims of the study were to explore the BRV in murine embryonic stem cell (mESC)-derived cardiomyocytes and to demonstrate the influence of antiarrhythmic drugs on BRV as has been shown in clinical trials previously. METHODS: The Microelectrode Array (MEA) technique was used to perform short-term recordings of extracellular field potentials (FPs) of spontaneously beating cardiomyocytes derived from mESCs (D3 cell line, αPig-44). Offline analysis was focused on time domain and nonlinear methods. RESULTS: The Poincaré-Plot analysis of measurements without pharmacological intervention revealed that three different shapes of scatter plots occurred most frequently. Comparable shapes have been described in clinical studies before. The antiarrhythmic drugs Ivabradine, Verapamil and Sotalol augmented BRV, whereas Flecainide decreased BRV parameters at low concentrations (SDSD 79.0 ± 8.7% of control at 10(-9) M, p < 0.05) and increased variability measures at higher concentrations (SDNN 258.8 ± 42.7% of control at 10(-5) M, p < 0.05). Amiodarone and Metoprolol did not alter BRV significantly. CONCLUSIONS: Spontaneously beating cardiomyocytes derived from mESCs showed BRV that appears to be similar to the HRV known from humans. Antiarrhythmic drugs affected BRV parameters similar to clinical observations. Therefore, our study demonstrates that this in vitro model can contribute to a better understanding of electrophysiological properties of mESC-derived cardiomyocytes and might serve as a valuable tool for drug safety screening.

Functional expression and regulation of hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in mouse iPS cell-derived cardiomyocytes after UTF1 -neo selection.

BACKGROUND/AIMS: In vitro reprogramming of somatic cells holds great potential to serve as an autologous source of cells for tissue repair. However, major difficulties in achieving this potential include obtaining homogeneous and stable cells for transplantation. High electrical activity of cells such as cardiomyocytes (CMs) is crucial for both, safety and efficiency of cell replacement therapy. Moreover, the function of the cardiac pacemaker is controlled by the activities of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Here we have examined changes in HCN gene expression and function during cardiomyogenesis. METHODS: We differentiated murine iPS cells selected by an undifferentiated transcription factor 1 (UTF1) -promoter-driven G418 resistance to CMs in vitro and characterized them by RT-PCR, immunocytochemistry, and electrophysiology. RESULTS: As key cardiac markers alpha-actinin and cardiac troponin T could be identified in derived CMs. Immunocytochemical staining of CMs showed the presence of all HCN subunits (HCN1-4). Electrophysiology experiments revealed developmental changes of action potentials and If currents as well as functional hormonal regulation and sensitivity to If channel blockers. CONCLUSION: We conclude that iPS cells derived from UTF-selection give rise to functional CMs in vitro, with established hormonal regulation pathways and functionally expressed If current in a development-dependent manner; and have all phenotypes with the pacemaker as predominant subtype. This might be of great importance for transplantation purposes.

Modulation of L-type calcium current by intracellular magnesium in differentiating cardiomyocytes derived from induced pluripotent stem cells.

Intracellular Mg(2+), which is implicated in arrhythmogenesis and transient cardiac ischemia, inhibits L-type Ca(2+) calcium channel current (ICaL) of adult cardiomyocytes (CMs). We take the advantage of an in vitro model of CMs based on induced pluripotent stem cells to investigate the effects of intracellular Mg(2+) on the phosphorylation or dephosphorylation processes of L-type Ca(2+) channels (LTCCs) at early and late stages of cardiac cell differentiation. Using the whole-cell patch-clamp technique, we demonstrate that increasing intracellular Mg(2+) concentration [Mg(2+)]i from 0.2 to 5 mM markedly reduced the peak of ICaL density, showing less effect on both the activation and inactivation properties in the late differentiation stage (LDS) of CMs more so than in the early differentiation stage (EDS). Increasing the [Mg(2+)]i from 0.2 to 2 mM in the presence of cAMP-dependent protein kinase A significantly decreased ICaL in LDS (70%) and in EDS (36%) CMs. In addition, the effect of forskolin was greatly attenuated in the presence of 2 mM [Mg(2+)]i in LDS but not in EDS CMs. The effect of forskolin was enhanced in the presence of ATP-γ-S in LDS CMs compared with EDS CMs. The exposure of both EDS and LDS CMs to 2 mM [Mg(2+)]i considerably reduced the effects of isobutylmethylxanthine (IBMX) and okadaic acid on ICaL. Our results provide evidence for differential regulation of LTCCs activities by cytosolic Mg(2+) concentration in developing cardiac cells and confirm that Mg(2+) acts under conditions that favor opening of the LTCCs caused by channel phosphorylation.

Evidence for a critical role of catecholamines for cardiomyocyte lineage commitment in murine embryonic stem cells.

Catecholamine release is known to modulate cardiac output by increasing heart rate. Although much is known about catecholamine function and regulation in adults, little is known about the presence and role of catecholamines during heart development. The present study aimed therefore to evaluate the effects of different catecholamines on early heart development in an in vitro setting using embryonic stem (ES) cell-derived cardiomyocytes. Effects of catecholamine depletion induced by reserpine were examined in murine ES cells (line D3, αPIG44) during differentiation. Cardiac differentiation was assessed by immunocytochemistry, qRT-PCR, quantification of beating clusters, flow cytometry and pharmacological approaches. Proliferation was analyzed by EB cross-section measurements, while functionality of cardiomyocytes was studied by extracellular field potential (FP) measurements using microelectrode arrays (MEAs). To further differentiate between substance-specific effects of reserpine and catecholamine action via α- and ß-receptors we proved the involvement of adrenergic receptors by application of unspecific α- and ß-receptor antagonists. Reserpine treatment led to remarkable down-regulation of cardiac-specific genes, proteins and mesodermal marker genes. In more detail, the average ratio of ∼40% spontaneously beating control clusters was significantly reduced by 100%, 91.1% and 20.0% on days 10, 12, and 14, respectively. Flow cytometry revealed a significant reduction (by 71.6%, n = 11) of eGFP positive CMs after reserpine treatment. By contrast, reserpine did not reduce EB growth while number of neuronal cells in reserpine-treated EBs was significantly increased. MEA measurements of reserpine-treated EBs showed lower FP frequencies and weak responsiveness to adrenergic and muscarinic stimulation. Interestingly we found that developmental inhibition after α- and ß-adrenergic blocker application mimicked developmental changes with reserpine. Using several methodological approaches our data suggest that reserpine inhibits cardiac differentiation. Thus catecholamines play a critical role during development.

Renal denervation - a clinical update and future directions.

The aim of this review is to give a contemporary update on renal denervation therapy focusing particularly on the scientific background and present literature as well as on different technical approaches and potential future directions.

A new model to perform electrophysiological studies in the early embryonic mouse heart.

BACKGROUND: The first electrocardiograms (ECGs) have been recorded with a capillary electrometer in the late 19(th) century by John Burdon Sanderson and Augustus Waller. In 1903 Willem Einthoven used the much more sensitive string galvanometer and was awarded Nobel Price in Medicine for this discovery. Though the physical principles of that era are still in use, there have been many advances but also challenges in cardiac electrophysiology over the last decades. One challenge is to record electrocardiograms of rather small animals such as mice and even smaller organisms such as their embryos. As mice belong to the most routinely used laboratory animals it is important to better understand their physiology and specific diseases. We therefore aimed to study whether it is feasible to measure electrical activities of embryonic mouse hearts. METHODS AND RESULTS: For our studies we used substrate-integrated Microelectrode Arrays combined with newly developed stimulation electrodes to perform electrophysiological studies in these hearts. The system enabled us to perform ECG-like recordings with atrio-ventricular (anterograde) and ventriculo-atrial (retrograde) stimulation. The functional separation of atria and ventricles, indicated by a stable atrio-ventricular conduction time, occurred clearly earlier than the morphological separation. Electrical stimulation induced a reversible prolongation of the anterograde and retrograde conduction up to atrio-ventricular conduction blocks at higher frequencies. CONCLUSION: These results yield new insight into functional aspects of murine cardiac development, and may help as a new diagnostic tool to uncover the functional and electrophysiological background of embryonic cardiac phenotypes of genetically altered mice.