Blood Pressure and Mortality in the 4D Study.

INTRODUCTION: Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) are risk factors for cardiovascular mortality (CVM). Pulse pressure (PP) is an easily available parameter of vascular stiffness, but its impact on CVM in chronic dialysis patients with diabetes is unclear. METHODS: Therefore, we have examined the predictive value of baseline, predialytic PP, SBP, DBP, and MAP in the German Diabetes and Dialysis (4D) study, a prospective, randomized, double-blind trial enrolling 1,255 patients with type 2 diabetes on hemodialysis in 178 German dialysis centers. RESULTS: Mean age was 66.3 years, mean blood pressure 146/76 mm Hg, mean time suffering from diabetes 18.1 years, and mean time on maintenance dialysis 8.3 months. Considered as continuous variables, PP, MAP, SBP, and DBP could not provide a significant mortality prediction for either cardiovascular or all-cause mortality. After dividing the cohort into corresponding tertiles, we also did not detect any significant mortality prediction for PP, SBP, DBP, or MAP, both for all-cause mortality and CVM after adjusting for age and sex. Nevertheless, when comparing the HR plots of the corresponding blood pressure parameters, a pronounced U-curve was seen for PP for both all-cause mortality and CVM, with the trough range being 70-80 mm Hg. DISCUSSION: In patients with end-stage renal disease and long-lasting diabetes mellitus predialytic blood pressure parameters at study entry are not predictive for mortality, presumably because there is a very high rate of competing mortality risk factors, resulting in overall very high rates of all-cause and CVM that may no longer be significantly modulated by blood pressure control.

Impact of baseline left ventricular ejection fraction on long-term outcomes in cardiac contractility modulation therapy.

BACKGROUND: Cardiac contractility modulation (CCM), being reserved for patients with symptomatic chronic heart failure (HF) and narrow QRS complex under guideline directed medical therapy, can recover initially reduced left ventricular ejection fraction (LVEF); however, the influence of pre-implantation LVEF on long-term outcomes is not fully understood. This study aimed to compare the effects of lower and higher preimplantation LVEF on long-term outcomes in CCM-therapy. METHODS: One-hundred seventy-two patients from our single-centre registry were retrospectively included (2002-2019). Follow-up data were collected up to 5 years after implantation. Patients were divided into Group 1 (baseline LVEF≤ 30%) and Group 2 (≥ 31%). Both groups were compared based on differences in survival, echocardiographic- and clinical parameters including LVEF, tricuspid annular plane systolic excursion (TAPSE), NYHA class or Minnesota living with heart failure questionnaire-score (MLWHFQ). RESULTS: 11% of the patients did have a LVEF ≥31%. Mean LVEF ± SD for both groups were 21.98 ± 5.4 versus 35.2 ± 3.7%, respectively. MLWHFQ (47 ± 21.2 vs. 42±21.4) and mean peak oxygen consumption (VO2, 13.6 ± 4.1 vs. 12.7 ± 2.8 ml/kg/min) were comparable between both groups. LVEF-grouping did not influence survival. Lower baseline LVEF resulted in significantly better recovery of echocardiographic parameters such as LVEF and TAPSE. Irrespective from baseline LVEF, both groups showed nearly comparable improvements for clinical parameters like NYHA-class and MLWHFQ. CONCLUSION: Long-term biventricular systolic recovery potential in CCM-therapy might be better for preimplantation LVEF values ≤30%, whereas clinical parameters such as NYHA-class can improve irrespective from baseline LVEF.

Polyvascular disease, pulse pressure and mortality.

Background: Peripheral arterial disease (PAD), coronary artery disease (CAD) and carotid stenosis (CS) are robust predictors of mortality. The value of individual vascular beds in polyvascular disease (PVD) to predict mortality in patients with atherosclerotic burden is not clear. Therefore, we have examined the predictive value of PAD, CAD and CS in patients at intermediate to high risk of cardiovascular (CV) disease. Patients and methods: In our retrospective observational study we analyzed baseline data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study, a monocentric cohort study of 3316 patients referred to coronary angiography. Results: As the number of atherosclerotic vascular beds increased, the hazard ratios (HRs) for both all-cause mortality and CV mortality significantly increased in a multivariate analysis after adjusting for age, sex, body mass index, diabetes mellitus and estimated glomerular filtration rate, with HRs of 1.36 (95%CI: 1.11-1.68), 2.56 (95%CI: 2.01-3.26), 2.84 (95%CI: 1.93-4.17) and 1.56 (95%CI: 1.19-2.06), 2.70 (95%CI: 1.97-3.72), 3.50 (95%CI: 2.19-5.62), respectively. The combination of PAD with either CAD or CS was associated with higher HRs for all-cause (HR 2.81 and 7.53, respectively) and CV (HRs 2.80 and 6.03, respectively) mortality compared with the combination of CAD and CS (HRs 1.94 and 2.43, respectively). The presence of PVD was associated with higher age, systolic blood pressure, pulse pressure (PP; a marker of vascular stiffness), former smoking and inversely with lower eGFR. Conclusions: We show that as the number of atherosclerotic vascular beds increases, all-cause and CV mortality rates increase in parallel. Simultaneous prevalence of PAD is associated with significantly higher all-cause and CV mortality rates compared with CS coexistence. Furthermore, increasing atherosclerotic load may contribute to vascular stiffness and impaired renal function.

Alterations in Doppler-derived renal venous stasis index during recompensation of right heart failure and fluid overload in a patient with pulmonary hypertension.

Renal congestion is becoming recognized as a potential contributor to cardiorenal syndromes. Adequate control of congestion with simultaneous preservation of renal function has been proposed as a central goal of the management of heart failure. We report our care of a 48-year-old woman suffering from right heart failure and massive fluid overload due to severe pulmonary hypertension secondary to a combination of left-heart disease and status after recurrent pulmonary embolisms. Alterations in Doppler-derived intrarenal venous flow patterns and a novel renal venous stasis index were used to evaluate improvement in renal venous congestion during recompensation. Due to refractory congestion despite optimal medical treatment and continuous veno-venous hemodialysis, a peritoneal dialysis catheter was placed to relieve the massive ascites. The paracentesis of ascites led to a significant loss of weight, normalization of hydration status with subsequent termination of continuous veno-venous hemodialysis, and a significant improvement in clinical and echocardiographic parameters. Renal Doppler ultrasonography showed continuous improvement in intrarenal venous flow patterns and the renal venous stasis index indicative of effective decongestion up to a normal intrarenal venous flow pattern and renal venous stasis index. Furthermore, residual renal function increased during follow-up. This case demonstrates the feasibility of renal Doppler ultrasonography as a simple, non-invasive, and integrative measure of renal congestion. The renal venous stasis index and intrarenal venous flow patterns may be useful to evaluate the treatment response and to guide therapy in patients with right heart failure.

Interventional Left Atrial Appendage Closure Affects the Metabolism of Acylcarnitines.

BACKGROUND: Left atrial appendage closure (LAAC) represents the interventional alternative to oral anticoagulation for stroke prevention in atrial fibrillation (AF). The metabolism of acylcarnitines was shown to affect cardiovascular diseases. This study evaluates the influence of successful LAAC on the metabolism of acylcarnitines. METHODS: Patients undergoing successful LAAC were enrolled prospectively. Peripheral blood samples for metabolomics measurements were collected immediately before (i.e., index) and six months after LAAC (i.e., mid-term). A targeted metabolomics analysis based on electrospray ionization-liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and MS/MS measurements was performed. RESULTS: 44 patients with non-valvular AF (median CHA2DS2-VASc score 4, median HAS-BLED score 4) and successful LAAC were included. Significant changes in acylcarnitine levels were found in the total cohort, which were mainly attributed to patients with impaired left ventricular and renal function, elevated amino-terminal pro-brain natriuretic peptide (NT-proBNP) and diabetes mellitus. Adjusted multivariable regression models revealed significant changes of five metabolites over mid-term follow-up: C2, C14:1, C16, and C18:1 decreased significantly (each p < 0.05); short-chain C5 acylcarnitine plasma levels increased significantly (p < 0.05). CONCLUSION: This study demonstrates that successful LAAC affects the metabolism of acylcarnitines at mid-term follow-up. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02985463.

The renin-angiotensin-aldosterone system, neurohumoral axis and cardiovascular mortality in LURIC.

Although neurohormones and Renin-Angiotensin-Aldosterone-System (RAAS) components are important predictors of cardiovascular mortality (CVM), their importance for predicting outcomes in patients with/without RAAS-blockers and different degrees of arterial stiffness is less understood. We therefore analyzed long-term data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study in 3316 patients subdivided according to pulse pressure (PP) and RAAS-blocker use. Patients on RAAS-inhibition had higher renin and noradrenaline, lower aldosterone and aldosterone/renin quotient (ARQ). Renin and noradrenaline significantly predicted CVM in patients without RAAS-blocker (HR = 1.17, 1.15) and in patients receiving angiotensin-converting-enzyme (ACE) inhibitors (HR = 1.17, 1.29), whereas aldosterone predicted CVM only in patients receiving ACE-inhibitors (HR = 1.13). CVM was predicted independently from PP by renin, noradrenaline and angiotensin II. Independently from RAAS inhibition renin decreased and ARQs increased with rising PP. Furthermore, noradrenaline increased with PP, but only without ACE-inhibition. The HR for CVM in the ACE-inhibitor group were 1.29, 1.28, 1.29 for renin in the first, second and third PP quartiles and 1.22, and 1.19 for aldosterone in the second and fourth quartile. Furthermore, we showed that noradrenaline predicts CVM in all PP quartiles in patients with ACE-inhibition. In the RAAS-blocker-free group, the HR for renin for CVM were 1.36 and 1.18 in the third and fourth PP quartiles, but neither aldosterone nor noradrenaline were predictive for CVM within the PP quartiles. Renin and noradrenaline are strong predictors of CVM regardless of RAAS blockade, whereas aldosterone is predictive only in the ACE-inhibitor group. Catecholamines but not renin are associated with rising PP.

Septal myocardial scar burden predicts the response to cardiac contractility modulation in patients with heart failure.

We hypothesized that myocardial septal scarring, assessed by cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE), at the site of cardiac contractility modulation (CCM) lead placement may predict treatment response. Eligible heart failure (HF) patients underwent LGE CMR imaging before CCM device implantation. The response to CCM therapy at follow-up was determined by a change in NYHA class and echocardiographic left ventricular ejection fraction (LVEF) assessment. Patients were classified as responders, if they showed an improvement in either NYHA class or improvement of LVEF by ≥ 5%. 58 patients were included. 67% of patients were classified as responders according to improved NYHA; 55% according to LVEF improvement. 74% of patients were responders if either NYHA class or LVEF improvement was observed. 90% of responders (according to NYHA class) showed septal LGE < 25% at septal position of the leads, while 44% of non-responders showed septal LGE > 25% (p < 0.01). In patients treated with CCM, an improvement of NYHA class was observed when leads were placed at myocardial segments with a CMR- LGE burden less than 25%.

EEG Synchronization-Parameters in Patients With Subcortical Arteriosclerotic Encephalopathy and Gait Disorder.

PURPOSE: Subcortical arteriosclerotic encephalopathy (SAE) is characterized by extensive white matter lesions in the MRI. Clinical symptoms are cognitive impairment, ranging from mild deficits to vascular dementia, impaired executive functioning, and gait disorders. In the EEG of SAE patients with vascular dementia, the lower frequencies are increased. However, it is unclear whether EEG changes also exist in SAE patients with gait disorders but without vascular dementia. METHODS: The authors analyzed the EEGs of 50 nondemented patients with SAE and gait disorders and 50 healthy controls applying pointwise transinformation as a measure of synchronization. RESULTS: Hundred seconds of waking EEG that appeared unaltered in visual analysis were sufficient to prove changes in synchronization. The authors found a decrease in the mean level of synchronization, combined with an elongation of synchronization time in all examined brain areas. These effects correlated slightly with the extent of subcortical lesions. CONCLUSIONS: Changes in EEG synchronization in patients with SAE and gait disorders seem to occur independently of cognitive function. The causal relationship of the changes in EEG synchronization and gait disorders remains to be clarified. The results of this study might point to a decrease in coupling efficiency in these patients, with the increase in synchronization duration as a possible compensatory mechanism. Because a time-efficient signal transmission particularly during gait execution is crucial, reduced efficiency might contribute to an impairment of postural stabilization. The study results might indicate a neuronal network for planning and execution of motor activity and particularly gait, extending from the frontal over the central to the parietal cortex.

Association of double product and pulse pressure with cardiovascular and all-cause mortality in the LURIC study.

Systolic (SBP) and diastolic blood pressure (DBP) and mean arterial pressure (MAP) are risk factors for cardiovascular mortality (CVM). Pulse pressure (PP) is considered as an easily available marker of vascular stiffness and the double product (DP) as a marker of cardiac workload. Therefore, we have examined the predictive value of PP and DP in the Ludwigshafen Risk and Cardiovascular Health study, a monocentric cohort study of 3316 patients referred to coronary angiography. An increase of SBP or PP by 1mmHg increased the risk of CVM with hazard ratios of 1.009 (95% CI, 1.005-1.012) and 1.016 (1.012-1.020), respectively. Increasing DP by 100 mm Hg/min was associated with a 1.010 (1.007-1.013) higher risk of CVM. In patient subgroups with coronary artery disease (CAD) and heart failure (HF), PP and DP predicted CVM better than SBP or MAP. In a multivariate analysis adjusted for sex, BMI, diabetes, eGFR, hazard ratios for CVM for z-standardized PP, DP, SBP, and HR were 1.20, 1.16, 1.12, and 1.14. After adding age to the multivariate analysis, only DP and HR remained significant. We provide evidence that PP and DP are powerful predictors of CVM and all-cause mortality in a CV medium- to high-risk population, especially in patients with CAD and HF. While DP proved to be an independent predictor of cardiovascular and all-cause mortality also in multivariate analysis, PP was no independent predictor in our cohort with widespread antihypertensive treatment (>85%). PP is associated with age, presence of diabetes, obesity, and impaired renal function.

Clinical and Operative Determinants of Acute Kidney Injury after Cardiac Surgery.

INTRODUCTION: Cardiac surgery-associated acute kidney injury (CSA-AKI) is associated with increased morbidity and mortality. OBJECTIVES: We aimed to identify potentially modifiable risk factors for CSA-AKI. METHODS: This was asingle-center retrospective cohort study of 495 adult patients undergoing cardiac surgery. AKI was diagnosed and staged using full KDIGO criteria incorporating baseline serum creatinine (SC) levels and correction of postoperative SC levels for fluid balance. We examined the association of routinely available clinical and laboratory data with AKI using multivariate logistic regression modeling. RESULTS: A total of 103 (20.8%) patients developed AKI: 16 (15.5%) patients were diagnosed with AKI upon hospital admission, and 87 (84.5%) patients were diagnosed with CSA-AKI. Correction of SC levels for fluid balance increased the number of AKI cases to 104 (21.0%), with 6 patients categorized to different AKI stages. Univariate logistic regression analysis identified five preoperative (age, sex, diabetes mellitus, preoperative systolic pulmonary arterial pressure [PSPAP], acute decompensated heart failure) and five intraoperative predictors of AKI (age, sex, red blood cell [RBC] volume transfused, use of minimally invasive surgery, duration of cardiopulmonary bypass). When all preoperative and intraoperative variables were incorporated into one model, six predictors remained significant (age, sex, use of minimally invasive surgery, RBC volume transfused, PSPAP, duration of cardiopulmonary bypass). Model discrimination performance showed an area under the curve of 0.69 for the model including only preoperative variables, 0.76 for the model including only intraoperative variables, and 0.77 for the model including all preoperative and intraoperative variables. CONCLUSIONS: Use of minimally invasive surgery and therapies mitigating PSPAP and intraoperative blood loss may offer protection against CSA-AKI.

Serum of patients with acute myocardial infarction prevents inflammation in iPSC-cardiomyocytes.

Acute myocardial infarction (MI) evokes a systemic inflammatory response and locally the degradation of the necrotic tissue, followed by scar formation. The mechanisms for containment of the infarct zone are not studied well. The study aimed to examine the response of healthy cardiomyocytes to serum of patients with myocardial infarction. Human iPSC-cardiomyocytes (iPSC-CM) generated from two healthy donors were incubated with serum of patients with MI with and without ventricular fibrillation (VF) or of healthy controls. Different cell adhesion molecules were studied by flow cytometry and immunostaining. Cellular electrophysiology was studied by patch clamp. The cell adhesion molecules CD54/ICAM-1, CD58/LFA-3 and CD321/JAM-A were expressed on iPSC-CM within the plasma membrane. Incubation with serum of MI patients reduced the levels of expression of CD54/ICAM-1 and CD321/JAM-A by 15-20%. VF serum was less effective than serum of MI patients without VF. MI serum or VF serum did not affect resting potential, action potential duration or maximum depolarization velocity. Myocardial infarction serum exerts anti-inflammatory effects on healthy cardiomyocytes without affecting their electrical activity, thus helping to contain the infarct zone and to protect healthy tissue. Ventricular fibrillation during MI drives healthy cardiomyocytes towards a pro-inflammatory phenotype.

Ion Channel Expression and Characterization in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

BACKGROUND: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are providing new possibilities for the biological study, cell therapies, and drug discovery. However, the ion channel expression and functions as well as regulations in hiPSC-CMs still need to be fully characterized. METHODS: Cardiomyocytes were derived from hiPS cells that were generated from two healthy donors. qPCR and patch clamp techniques were used for the study. RESULTS: In addition to the reported ion channels, INa, ICa-L, ICa-T, If, INCX, IK1, Ito, IKr, IKs IKATP, IK-pH, ISK1-3, and ISK4, we detected both the expression and currents of ACh-activated (KACh) and Na+-activated (KNa) K+, volume-regulated and calcium-activated (Cl-Ca) Cl-, and TRPV channels. All the detected ion currents except IK1, IKACh, ISK, IKNa, and TRPV1 currents contribute to AP duration. Isoprenaline increased ICa-L, If, and IKs but reduced INa and INCX, without an effect on Ito, IK1, ISK1-3, IKATP, IKr, ISK4, IKNa, ICl-Ca, and ITRPV1. Carbachol alone showed no effect on the tested ion channel currents. CONCLUSION: Our data demonstrate that most ion channels, which are present in healthy or diseased cardiomyocytes, exist in hiPSC-CMs. Some of them contribute to action potential performance and are regulated by adrenergic stimulation.

Modeling Short QT Syndrome Using Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

BACKGROUND: Short QT syndrome (SQTS), a disorder associated with characteristic ECG QT-segment abbreviation, predisposes affected patients to sudden cardiac death. Despite some progress in assessing the organ-level pathophysiology and genetic changes of the disorder, the understanding of the human cellular phenotype and discovering of an optimal therapy has lagged because of a lack of appropriate human cellular models of the disorder. The objective of this study was to establish a cellular model of SQTS using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS: This study recruited 1 patient with short QT syndrome type 1 carrying a mutation (N588K) in KCNH2 as well as 2 healthy control subjects. We generated hiPSCs from their skin fibroblasts, and differentiated hiPSCs into cardiomyocytes (hiPSC-CMs) for physiological and pharmacological studies. The hiPSC-CMs from the patient showed increased rapidly activating delayed rectifier potassium channel current (IKr) density and shortened action potential duration compared with healthy control hiPSC-CMs. Furthermore, they demonstrated abnormal calcium transients and rhythmic activities. Carbachol increased the arrhythmic events in SQTS but not in control cells. Gene and protein expression profiling showed increased KCNH2 expression in SQTS cells. Quinidine but not sotalol or metoprolol prolonged the action potential duration and abolished arrhythmic activity induced by carbachol. CONCLUSIONS: Patient-specific hiPSC-CMs are able to recapitulate single-cell phenotype features of SQTS and provide novel opportunities to further elucidate the cellular disease mechanism and test drug effects.

Estradiol protection against toxic effects of catecholamine on electrical properties in human-induced pluripotent stem cell derived cardiomyocytes.

BACKGROUND AND PURPOSE: Previous studies revealed that Takotsubo cardiomyopathy (TTC), a transient disorder of ventricular dysfunction affecting predominantly postmenopausal women, is associated with acquired long QT syndrome and arrhythmias, but the exact pathophysiologic mechanism is unknown. Our aim is to investigate the electrophysiological mechanism for QT-prolongation in TTC-patients by using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS: hiPSC-CMs, which were generated from human skin fibroblasts of three healthy donors, were treated by estradiol (10µM for one week) and a toxic concentration of isoprenaline (Iso, 1mM for 2h). Patch clamp techniques, qPCR and fluorescence-activated cell sorting (FACS) were employed for the study. KEY RESULTS: Iso enhanced late INa and suppressed Ito and thus prolonged the action potential duration (APD), suggesting possible reasons for arrhythmias in TTC. Iso elevated the production of reactive oxygen species (ROS). N-acetylcystein (1mM), a ROS-blocker, abolished the effects of Iso on late INa and Ito. H2O2 (100µM) mimicked Iso effects on late INa and Ito. These data indicate that the effects of Iso were mediated by ROS. Metoprolol (1mM), a beta-blocker, prevented the effects of Iso on late INa and APD, confirming the adrenoceptor-dependent effects of Iso. Estradiol treatment prevented the APD-prolongation, attenuated the enhancement of INa, diminished the reduction of Ito, suppressed ROS-production induced by Iso and reduced the expression levels of adrenoceptors, suggesting protective effects of estragon against toxic effects of catecholamine. CONCLUSIONS: Estradiol has protective effects against catecholamine excess and hence reduction in estrogen level may increase the risk of acquired long QT syndrome in TTC.

Ion Channel Dysfunctions in Dilated Cardiomyopathy in Limb-Girdle Muscular Dystrophy.

BACKGROUND: Limb-Girdle muscular dystrophies (LGMD) are a heritable group of genetically determined disorders with a primary involvement of the pelvic or shoulder girdle musculature with partially cardiac manifestation, such as dilated cardiomyopathy (DCM) and life-threatening tachyarrhythmia. We report here that human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes from a patient with LGMD2I and DCM associated with recurrent ventricular tachycardia displayed ion channel dysfunction and abnormality of calcium homeostasis. METHODS: Dermal fibroblasts obtained from a patient with LGMD2I harboring a fukutin-related protein gene mutation (826C>A; Leu276Ile) and 3 healthy donors were reprogrammed to hiPSCs. The hiPSCs were differentiated into cardiomyocytes and used for biological and electrophysiological studies. RESULTS: Compared with hiPSC cardiomyocytes from the healthy donors, the hiPSC cardiomyocytes from the patient exhibited abnormal action potentials characterized by reduced amplitude and upstroke velocity. The peak and late Na channel currents (INa) as well as the peak L-type calcium channel currents were significantly reduced. The expression of SCN5A and CACNA1C was reduced in DCM cardiomyocytes, consistent with reduction of INa and L-type calcium channel currents. In addition, the rapidly activating delayed rectifier potassium current (IKr) was reduced, whereas the transient outward current (Ito) and slowly activating delayed rectifier potassium current (IKs) were similar in DCM and control cardiomyocytes. Finally, a significant reduction of systolic and diastolic intracellular Ca2+ concentrations was detected in DCM cardiomyocytes. CONCLUSIONS: This study demonstrates that patient-specific hiPSC cardiomyocytes can recapitulate some phenotypic properties of LGMD2I with DCM and provide a platform for studies on the cardiac events in LGMD.

Lipopolysaccharides induced inflammatory responses and electrophysiological dysfunctions in human-induced pluripotent stem cell derived cardiomyocytes.

Severe infections like sepsis lead frequently to cardiomyopathy. The mechanisms are unclear and an optimal therapy for septic cardiomyopathy still lacks. The aim of this study is to establish an endotoxin-induced inflammatory model using human induced pluripotent stem cell (hiPSC) derived cardiomyocytes (hiPSC-CMs) for mechanistic and therapeutic studies. hiPSC-CMs were treated by lipopolysaccharide (LPS) in different concentrations for different times. ELISA, FACS, qPCR, and patch-clamp techniques were used for the study. TLR4 (Toll-like receptor 4) and its associated proteins, CD14, LBP (lipopolysaccharide binding protein), TIRAP (toll-interleukin 1 receptor domain containing adaptor protein), Ly96 (lymphocyte antigen 96) and nuclear factor kappa B as well as some pro-and anti-inflammatory factors are expressed in hiPSC-CMs. LPS-treatment for 6 hours increased the expression levels of pro-inflammatory and chemotactic cytokines (TNF-a, IL-1ß, IL-6, CCL2, CCL5, IL-8), whereas 48 hour-treatment elevated the expression of anti-inflammatory factors (IL-10 and IL-6). LPS led to cell injury resulting from exaggerated cell apoptosis and necrosis. Finally, LPS inhibited small conductance Ca2+-activated K+ channel currents, enhanced Na+/Ca2+-exchanger currents, prolonged action potential duration, suggesting cellular electrical dysfunctions. Our data demonstrate that hiPSC-CMs possess the functional reaction system involved in endotoxin-induced inflammation and can model some bacterium-induced inflammatory responses in cardiac myocytes.

Hyperthermia Influences the Effects of Sodium Channel Blocking Drugs in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

INTRODUCTION: Fever can increase the susceptibility to supraventricular and ventricular arrhythmias, in which sodium channel dysfunction has been implicated. Whether fever influences the efficacy of sodium channel blocking drugs is unknown. The current study was designed to investigate the temperature dependent effects of distinct sodium channel blocking drugs on the sodium currents in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS: hiPSC-CMs were generated from human skin fibroblasts of a healthy donor. The peak and late sodium currents (INa), steady-state activation, inactivation and recovery from inactivation of INa in hiPSC-CMs were analyzed using the whole-cell patch clamp technique. The effects of different concentrations of the antiarrhythmic drugs flecainide, lidocaine, ajmaline and the antianginal drug ranolazine on INa were tested at 36°C and 40°C. Increasing the temperature of the bath solution from 36°C to 40°C enhanced the inhibition of peak INa but reduced the inhibition of late INa by flecainide and lidocaine. By contrast, increasing the temperature reduced the effect of ajmaline and ranolazine on the peak INa but not late INa. None of the tested drugs showed temperature-dependent effects on the steady-state activation and inactivation as well as on the recovery from inactivation of INa in hiPSC-CMs. CONCLUSIONS: Temperature variation from the physiological to the febrile range apparently influences the effects of sodium channel blockers on the sodium currents. This may influence their antiarrhythmic efficacy in patients suffering from fever.