Coordinated Tbx3 / Tbx5 transcriptional control of the adult ventricular conduction system.

The cardiac conduction system (CCS) orchestrates the electrical impulses that enable coordinated contraction of the cardiac chambers. The T-box transcription factors TBX3 and TBX5 are required for cardiac conduction system development and associated with overlapping and distinct human cardiac conduction system diseases. We evaluated the coordinated role of Tbx3 and Tbx5 in the murine ventricular conduction system (VCS). We engineered a compound Tbx3:Tbx5 conditional knockout allele for both genes located in cis on mouse chromosome 5. Conditional deletion of both T-box transcriptional factors in the ventricular conduction system, using the VCS-specific Mink:Cre, caused loss of VCS function and molecular identity. Combined Tbx3 and Tbx5 deficiency in the adult VCS led to conduction defects, including prolonged PR and QRS intervals and elevated susceptibility to ventricular tachycardia. These electrophysiologic defects occurred prior to detectable alterations in cardiac contractility or histologic morphology, indicative of a primary conduction system defect. Tbx3:Tbx5 double knockout VCS cardiomyocytes revealed a transcriptional shift towards non-CCS-specialized working myocardium, suggesting reprogramming of their cellular identity. Furthermore, optical mapping revealed a loss of VCS-specific conduction system propagation. Collectively, these findings indicate that Tbx3 and Tbx5 coordinate to control VCS molecular fate and function, with implications for understanding cardiac conduction disorders in humans.

Comprehensive Analysis of Anticoagulant Therapy in Patients With Isolated Atrial Flutter.

Limited comparative data exist regarding the risk of cardiogenic emboli in patients with isolated atrial flutter (AFL). Some studies suggest a lower complication risk in AFL than atrial fibrillation (Afib); however, methodologic limitations and conflicting reports necessitate a comprehensive investigation. Our analysis proposes that isolated AFL carries a lower risk of ischemic events and left atrial thrombus formation than AFib. Importantly, we caution against applying stroke risk assessment approaches designed for AFib to patients with AFL because it may lead to harmful overestimations and unnecessary anticoagulant prescriptions. Furthermore, we highlight the current lack of sufficient data to determine the overall clinical benefit of prolonged anticoagulant therapy in patients with isolated AFL, especially when CHA2DS2-VASc index values are below 4. This review challenges existing perceptions, offering insights into the nuanced risk profiles of the transitional nature of isolated AFL because of the high incidence of AFib development within a year of AFL diagnosis. Tailored risk assessments and further research are essential for precise clinical decision-making in this dynamic landscape.

Sympathetic remodeling and altered angiotensin-converting enzyme 2 localization occur in patients with cardiac disease but are not exacerbated by severe COVID-19.

PURPOSE: Remodeling of sympathetic nerves and ACE2 has been implicated in cardiac pathology, and ACE2 also serves as a receptor for SARS-CoV-2. However, there is limited histological knowledge about the transmural distribution of sympathetic nerves and the cellular localization and distribution of ACE2 in human left ventricles from normal or diseased hearts. Goals of this study were to establish the normal pattern for these parameters and determine changes that occurred in decedents with cardiovascular disease alone compared to those with cardiac pathology and severe COVID-19. METHODS: We performed immunohistochemical analysis on sections of left ventricular wall from twenty autopsied human hearts consisting of a control group, a cardiovascular disease group, and COVID-19 ARDS, and COVID-19 non-ARDS groups. RESULTS: Using tyrosine hydroxylase as a noradrenergic marker, we found substantial sympathetic nerve loss in cardiovascular disease samples compared to controls. Additionally, we found heterogeneous nerve loss in both COVID-19 groups. Using an ACE2 antibody, we observed robust transmural staining localized to pericytes in the control group. The cardiovascular disease hearts displayed regional loss of ACE2 in pericytes and regional increases in staining of cardiomyocytes for ACE2. Similar changes were observed in both COVID-19 groups. CONCLUSIONS: Heterogeneity of sympathetic innervation, which occurs in cardiac disease and is not increased by severe COVID-19, could contribute to arrhythmogenesis. The dominant localization of ACE2 to pericytes suggests that these cells would be the primary target for potential cardiac infection by SARS-CoV-2. Regional changes in ACE2 staining by myocytes and pericytes could have complex effects on cardiac pathophysiology.

Ryanodine receptor inhibition with acute dantrolene treatment reduces arrhythmia susceptibility in human hearts.

Ryanodine receptor 2 (RyR2) hyperactivity is observed in structural heart diseases that are a result of ischemia or heart failure. It causes abnormal calcium handling and calcium leaks that cause metabolic, electrical, and mechanical dysfunction, which can trigger arrhythmias. Here, we tested the antiarrhythmic potential of dantrolene (RyR inhibitor) in human hearts. Human hearts not used in transplantation were obtained, and right ventricular outflow tract (RVOT) wedges and left ventricular (LV) slices were prepared. Pseudo-ECGs were recorded to determine premature ventricular contraction (PVC) incidences. Optical mapping was performed to determine arrhythmogenic substrates. After baseline optical recordings, tissues were treated with 1) isoproterenol (250 nM), 2) caffeine (200 mM), and 3) dantrolene (2 or 10 mM). Optical recordings were obtained after each treatment. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Isoproterenol shortened action potential duration (APD) in the RV, RVOT, and LV regions and shortened calcium transient duration (CaTD) in the LV. Caffeine further shortened APD in the RV, did not modulate APD in the RVOT, and prolonged APD in the LV. In addition, in the LV, CaTD prolongation was also observed. More importantly, adding dantrolene did not alter APD in the RV or RVOT regions but produced a trend toward APD prolongation and significant CaTD prolongation in the LV, restoring these parameters to baseline values. In conclusions, dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates in the human heart and could be a novel antiarrhythmic therapy in patients with structural heart disease.NEW & NOTEWORTHY Ryanodine receptor 2 hyperactivity is observed in structural heart diseases caused by ischemia or heart failure. It causes abnormal calcium leaks, which can trigger arrhythmias. To prevent arrhythmias, we applied dantrolene in human hearts ex vivo. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates and could be a novel antiarrhythmic therapy in patients with structural heart disease.

A Sewing Approach to the Fabrication of Eco/bioresorbable Electronics.

Eco/bioresorbable electronics represent an emerging class of technology defined by an ability to dissolve or otherwise harmlessly disappear in environmental or biological surroundings after a period of stable operation. The resulting devices provide unique capabilities as temporary biomedical implants, environmental sensors, and related systems. Recent publications report schemes to overcome challenges in fabrication that follow from the low thermostability and/or high chemical reactivity of the eco/bioresorbable constituent materials. Here, this work reports the use of high-speed sewing machines, as the basis for a high-throughput manufacturing technique that addresses many requirements for these applications, without the need for high temperatures or reactive solvents. Results demonstrate that a range of eco/bioresorbable metal wires and polymer threads can be embroidered into complex, user-defined conductive patterns on eco/bioresorbable substrates. Functional electronic components, such as stretchable interconnects and antennas are possible, along with fully integrated systems. Examples of the latter include wirelessly powered light-emitting diodes, radiofrequency identification tags, and temporary cardiac pacemakers. These advances add to a growing range of options in high-throughput, automated fabrication of eco/bioresorbable electronics.

Soft, bioresorbable, transparent microelectrode arrays for multimodal spatiotemporal mapping and modulation of cardiac physiology.

Transparent microelectrode arrays (MEAs) that allow multimodal investigation of the spatiotemporal cardiac characteristics are important in studying and treating heart disease. Existing implantable devices, however, are designed to support chronic operational lifetimes and require surgical extraction when they malfunction or are no longer needed. Meanwhile, bioresorbable systems that can self-eliminate after performing temporary functions are increasingly attractive because they avoid the costs/risks of surgical extraction. We report the design, fabrication, characterization, and validation of a soft, fully bioresorbable, and transparent MEA platform for bidirectional cardiac interfacing over a clinically relevant period. The MEA provides multiparametric electrical/optical mapping of cardiac dynamics and on-demand site-specific pacing to investigate and treat cardiac dysfunctions in rat and human heart models. The bioresorption dynamics and biocompatibility are investigated. The device designs serve as the basis for bioresorbable cardiac technologies for potential postsurgical monitoring and treating temporary patient pathological conditions in certain clinical scenarios, such as myocardial infarction, ischemia, and transcatheter aortic valve replacement.

MicroRNAs as Novel Biomarkers for P2Y12 - Inhibitors Resistance Prediction.

AIM: The aim of this study is to assess 6 micro-RNAs: miR-126, miR-223, miR-150, miR-29, miR-34, miR-142 as potential biomarkers for P2Y12- inhibitors resistance prediction. METHODS: Eighty patients with an acute coronary syndrome undergoing percutaneous coronary intervention treated in a multidisciplinary hospital in Moscow with DAPT (either with ticagrelor, n=45, or clopidogrel, n=35) were enrolled. The carriership of 6 clinically relevant polymorphisms for ticagrelor and 17 for clopidogrel was detected. Expression levels of six prospective miRNAs were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of cortisol and 6ß-hydroxycortisol. RESULTS: The polymorphisms of the P2Y12-inhibitors ADME genes that demonstrated statistically significant connection with miRNA expression levels are as follows: P2Y12R (A>G, rs3732759) and miR-29 (p=0.017), miR-34 (p=0.003); CYP2C19*17 (C-806T, rs1224856) and miR-142 (p=0.012); PON1 (Q192R, rs662) and miR-29 (p=0.004), ABCG2 (G>T, rs2231142) and miR-34 (p=0.007). MiRNAs expression levels showed connection with the results of the platelet reactivity assessment by utilizing VerifyNow assay ("Instrumentation laboratory", MA, US). MiR-126 (ß coefficient=-0.076, SE=0.032, p=0.021), miR-223 (ß coefficient=-0.089, SE=0.041, p=0.032), miR-29 (ß coefficient=-0.042, SE=0.018, p=0.026), miR-142 (ß coefficient=-0.072, SE=0.026, p=0.008) have the potential to be used as biomarkers and may substitute platelet reactivity testing. CONCLUSION: This study has revealed new biomarkers for P2Y12-inhibitors resistance testing: miR-29, miR-34, miR-126, miR-142, miR-223.

MicroRNAs as novel biomarkers for rivaroxaban therapeutic drug monitoring.

OBJECTIVES: The aim of this study is to assess micro-RNAs miR-142 and miR-39 as potential biomarkers for drug-monitoring of rivaroxaban among elderly patients with atrial fibrillation. METHODS: The study involved 57 patients with median (ME) age 87 years [80-94 years old] with nonvalvular atrial fibrillation admitted to a multidisciplinary hospital in Moscow. High-performance liquid chromatography with mass-spectrometry detection (HPLC-MS) was carried out to measure rivaroxaban concentrations. Carriership of CYP3A4 and ABCB1 was detected. MiRNA expression levels were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of 6ß-hydroxycortisol and cortisol. RESULTS: The miR-142 expression levels of patients with CC allelic variant polymorphism ABCB1 3435 C>T (rs1045642) were significantly higher compared to CT and TT variants 31.69 ± 1.60 vs. 34.06 ± 1.66 vs. 33.16 ± 1.77 (p=0.021). Carriers of TT allelic variant polymorphism ABCB1 rs4148738 had a higher concentration of the 6-beta-hydroxycortisol in urine compared to CC and CT variants 3,467.35 ± 1,055.53 vs. 3,453.52 ± 1,516.89 vs. 2,593.30 ± 1,172.52 (p=0.029). As for CYP3A4*22, the carriers of CC allelic variant had higher prothrombin time 14.10 ± 2.17 vs. 11.87 ± 0.60 and INR 1.31 ± 0.20 vs. 1.1 ± 0.06 but lower Quick's value 74.52 ± 16.84 vs. 97.55 ± 10.54 (p=0.059). A positive correlation between the Ct miR-142 and the aPTT p=0.019 was noted. Also miR-142 has a correlation with Quick's value p=0.095. There is no statistically significant connection between miR-142 and miR-39 expression levels and the plasma concentration of rivaroxaban (b coefficient=-2.055, SE 3.952, p=0.605 and b coefficient=1.546, SE 9.887, p=0.876 in the linear regression model respectively). CONCLUSIONS: This study has assessed new potential biomarkers for rivaroxaban therapeutic drug monitoring: miR-142 and miR-39.

MicroRNAs as novel biomarkers for rivaroxaban therapeutic drug monitoring.

OBJECTIVES: The aim of this study is to assess micro-RNAs miR-142 and miR-39 as potential biomarkers for drug-monitoring of rivaroxaban among elderly patients with atrial fibrillation. METHODS: The study involved 57 patients with median (ME) age 87 years [80-94 years old] with nonvalvular atrial fibrillation admitted to a multidisciplinary hospital in Moscow. High-performance liquid chromatography with mass-spectrometry detection (HPLC-MS) was carried out to measure rivaroxaban concentrations. Carriership of CYP3A4 and ABCB1 was detected. MiRNA expression levels were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of 6ß-hydroxycortisol and cortisol. RESULTS: The miR-142 expression levels of patients with CC allelic variant polymorphism ABCB1 3435 C>T (rs1045642) were significantly higher compared to CT and TT variants 31.69 ± 1.60 vs. 34.06 ± 1.66 vs. 33.16 ± 1.77 (p=0.021). Carriers of TT allelic variant polymorphism ABCB1 rs4148738 had a higher concentration of the 6-beta-hydroxycortisol in urine compared to CC and CT variants 3,467.35 ± 1,055.53 vs. 3,453.52 ± 1,516.89 vs. 2,593.30 ± 1,172.52 (p=0.029). As for CYP3A4*22, the carriers of CC allelic variant had higher prothrombin time 14.10 ± 2.17 vs. 11.87 ± 0.60 and INR 1.31 ± 0.20 vs. 1.1 ± 0.06 but lower Quick's value 74.52 ± 16.84 vs. 97.55 ± 10.54 (p=0.059). A positive correlation between the Ct miR-142 and the aPTT p=0.019 was noted. Also miR-142 has a correlation with Quick's value p=0.095. There is no statistically significant connection between miR-142 and miR-39 expression levels and the plasma concentration of rivaroxaban (b coefficient=-2.055, SE 3.952, p=0.605 and b coefficient=1.546, SE 9.887, p=0.876 in the linear regression model respectively). CONCLUSIONS: This study has assessed new potential biomarkers for rivaroxaban therapeutic drug monitoring: miR-142 and miR-39.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation.

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation.

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

Clinically relevant pharmacogenetic markers in Tatars and Balkars.

This study was aimed to investigate the prevalence of CYP2C9*2 (p.430C > T, rs1799853), CYP2C9*3 (p.1075A > C, rs1057910), CYP4F2*3 (p.1297G > A, rs2108622), CYP2C19*2 (p.681G > A, rs4244285), CYP2C19*3 (p.636G > A, rs4986893), CYP2C19*17 (p.1260C > A, rs12248560), ABCB1 (p.3435C > T, rs1045642), CYP2D6*4 (p.1846G > A, rs3892097), SLCO1B1*5 (p.521T > C, rs4149056) and CES1 (p.1168-33A > C, rs2244613) among Tatars and Balkars ethnic groups living in Russia to provide a basis for future clinical studies concerning on understanding of population-level differences in drug response. The study involved 341 apparently healthy, unrelated, and chronic medication-free volunteers of both sexes of ethnic groups of Tatars and Balkars living in Volga and Caucasus regions of Russia. Genotyping was performed using real-time polymerase chain reaction-based methods. The allelic prevalence of studied markers in ethnic groups were compared with Russians as a largest ethnic group in Russia. Statistically significant differences for the following gene polymorphisms were found between both ethnic groups in respect of different markers and with Russians. Our study shows differences in prevalence of the main relevant pharmacogenetic markers in Tatars and Balkars. These findings should be taken into consideration for personalization algorithms development and pharmacogenetics implementation in regions with ethnic minorities as Russia has.

Do CYP2C19 and ABCB1 gene polymorphisms and low CYP3A4 isoenzyme activity have an impact on stent implantation complications in acute coronary syndrome patients?

AIM: The aim of this study was to determine the impact of CYP2C19 and ABCB1 gene polymorphisms and CYP3A4 isoenzyme activity on stent implantation complications among patients with an acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI). PATIENTS AND METHODS: Seventy-six patients (median age 63, range 37-91 years) with an ACS who underwent PCI were screened for CYP2C19 and ABCB1 gene polymorphisms with real-time polymerase chain reaction: CYP2C19*2, CYP2C19*17, and ABCB1 3435. CYP3A4 isoenzyme activity was determined by urine cortisol and 6-beta-hydroxycortisol levels. Stent implantation complications such as stent thrombosis (n=2) and restenosis (n=1) were observed among drug-eluting stent recipients. RESULTS: Low mean 6-beta-hydroxycortisol/cortisol ratio is indicative of impaired CYP3A4 activity and was associated with higher risk of thrombosis (b coefficient=0.022, SE 0.009, p=0.021 in the linear regression model). The increase in the length of the implanted stent was associated with higher risk of restenosis (b coefficient=0.006, SE=0.002, p=0.001 in the linear regression model). The presence of the CYP2C19*2 polymorphism did not affect the incidence of stent thrombosis (b coefficient=-1.626, SE=1.449, p=0.262 in the logistic regression model), nor did the CYP2C19*17 (b coefficient=-0.907, SE=1.438, p=0.528 in the logistic regression model) and ABCB1 3435 polymorphisms (b coefficient=1.270, SE=1.442, p=0.378 in the logistic regression model). CONCLUSION: We did not find evidence that the presence of CYP2C19*2, CYP2C19*17, and ABCB1 3435 polymorphisms may jeopardize the safety of stent implantation in patients with an ACS. Patients with low CYP3A4 isoenzyme activity may have increased risk of stent thrombosis.

An Intracardiac Soft Robotic Device for Augmentation of Blood Ejection from the Failing Right Ventricle.

We introduce an implantable intracardiac soft robotic right ventricular ejection device (RVED) for dynamic approximation of the right ventricular (RV) free wall and the interventricular septum (IVS) in synchrony with the cardiac cycle to augment blood ejection in right heart failure (RHF). The RVED is designed for safe and effective intracardiac operation and consists of an anchoring system deployed across the IVS, an RV free wall anchor, and a pneumatic artificial muscle linear actuator that spans the RV chamber between the two anchors. Using a ventricular simulator and a custom controller, we characterized ventricular volume ejection, linear approximation against different loads and the effect of varying device actuation periods on volume ejection. The RVED was then tested in vivo in adult pigs (n = 5). First, we successfully deployed the device into the beating heart under 3D echocardiography guidance (n = 4). Next, we performed a feasibility study to evaluate the device's ability to augment RV ejection in an experimental model of RHF (n = 1). RVED actuation augmented RV ejection during RHF; while further chronic animal studies will provide details about the efficacy of this support device. These results demonstrate successful design and implementation of the RVED and its deployment into the beating heart. This soft robotic ejection device has potential to serve as a rapidly deployable system for mechanical circulatory assistance in RHF.