Rivaroxaban, a direct inhibitor of coagulation factor Xa, attenuates adverse cardiac remodeling in rats by regulating the PAR-2 and TGF-ß1 signaling pathways.

Background: Factor Xa (FXa) not only plays an active role in the coagulation cascade but also exerts non-hemostatic signaling through the protease-activated receptors (PARs). This study aimed to investigate whether the FXa inhibitor, Rivaroxaban (RIV), attenuates adverse cardiac remodeling in rats with myocardial infarction (MI) and to identify the underlying molecular mechanisms it uses. Methods: An MI model was induced in eight-week-old, male Wistar rats, by permanent ligation of the left anterior descending coronary artery. MI rats were randomly assigned to receive RIV or protease-activated receptors 2-antagonist (PAR-2 antagonist, FSLLRY) treatment for four weeks. Histological staining, echocardiography and hemodynamics were used to assess the cardioprotective effects of RIV. Meanwhile, pharmacological approaches of agonist and inhibitor were used to observe the potential pathways in which RIV exerts antifibrotic effects in neonatal rat cardiac fibroblasts (CFs). In addition, real-time PCR and western blot analysis were performed to examine the associated signaling pathways. Results: RIV presented favorable protection of left ventricular (LV) cardiac function in MI rats by significantly reducing myocardial infarct size, ameliorating myocardial pathological damage and improving left ventricular (LV) remodeling. Similar improvements in the PAR-2 antagonist FSLLRY and RIV groups suggested that RIV protects against cardiac dysfunction in MI rats by ameliorating PAR-2 activation. Furthermore, an in vitro model of fibrosis was then generated by applying angiotensin II (Ang II) to neonatal rat cardiac fibroblasts (CFs). Consistent with the findings of the animal experiments, RIV and FSLLRY inhibited the expression of fibrosis markers and suppressed the intracellular upregulation of transforming growth factor ß1 (TGFß1), as well as its downstream Smad2/3 phosphorylation effectors in Ang II-induced fibrosis, and PAR-2 agonist peptide (PAR-2 AP) reversed the inhibition effect of RIV. Conclusions: Our findings demonstrate that RIV attenuates MI-induced cardiac remodeling and improves heart function, partly by inhibiting the activation of the PAR-2 and TGF-ß1 signaling pathways.

Clinical profile and prognosis of elderly patients with left ventricular thrombus after anticoagulation.

BACKGROUND: Contemporary data regarding the clinical characteristics and prognosis of left ventricular thrombus (LVT) in older adults (aged ≥ 65 years old) are lacking. In this study, we characterized elderly patients with LVT (aged ≥ 65 years old) and investigated the long-term prognosis in this highly vulnerable patient population. METHODS: This single-center, retrospective study was conducted from January 2017 to December 2022. Patients with a reported LVT were assessed primarily by transthoracic echocardiography (TEE) and classified into two groups: elderly LVT groups and younger LVT groups. All patients were treated with anticoagulant treatment. Major adverse cardiovascular event (MACE) was defined as the composite of all-cause mortality, systemic embolism, and rehospitalization for cardiovascular events. Survival analyses were performed with the Kaplan-Meier method and Cox proportional-hazard model. RESULTS: A total of 315 eligible patients were included. Compared to the younger LVT group (n = 171), the elderly LVT group (n = 144) had a lower proportion of males and lower serum creatinine clearance, as well as a higher level of NT-proBNP, and a higher rate of history of systemic embolism. LVT resolution occurred in 59.7% and 69.0% of patients in the elderly LVT group and younger LVT group, respectively, with no significant difference (adjusted HR, 0.97; 95% CI, 0.74-1.28; P = 0.836). Yet, elderly patients with LVT, had higher prevalence rates of MACE (adjusted HR, 1.52; 95% CI, 1.10-2.11; P = 0.012), systemic embolism (adjusted HR, 2.81; 95% CI, 1.20-6.59; P = 0.017) and all-cause mortality (adjusted HR, 2.20; 95% CI, 1.29-3.74; P = 0.004) compared with younger patients with LVT. After adjusting for mortality in the Fine-Gray model, similar results were observed. Additionally, patients treated with different anticoagulation therapies (DOACs vs. warfarin) achieved a similar improvement in prognosis (P > 0.05) or LVT resolution (P > 0.05) in elderly patients with LVT. CONCLUSIONS: Our results found that elderly patients experiencing LVT have a poor prognosis compared with the younger ones. Clinical prognosis in elderly patients did not significantly differ with the type of anticoagulant used. With aging societies worldwide, further evidence of antithrombotic therapy in elderly individuals with LVT is necessary.

Silencing of UTX Mitigates Aging-Associated Cardiac Fibrosis via Blocking Cardiac Fibroblasts-to-Myofibroblasts Trans-Differentiation.

BACKGROUND: Cardiac fibrosis increases with age. Fibroblast activation plays an essential role in cardiac fibrosis. Histone modifications are involved in various chromatin-dependent processes. Attenuation of the histone H3 trimethylation on lysine 27 demethylase UTX by RNA interference or heterozygous mutation extends lifespan in worm. The objective of this study was to explore whether epigenetic silencing of UTX mitigates aging-associated cardiac fibrosis. METHODS: Middle-aged mice (15 months old) were used and started to receive adeno-associated virus-scrambled-small hairpin RNA and adeno-associated virus-UTX-small hairpin RNA every 3 months from 15 months to 21 months, respectively. The mice were euthanized at 24 months of age (length of the study). RESULTS: Adeno-associated virus-UTX-small hairpin RNA delivery significantly attenu-ated aging-associated increase in blood pressure, especially in diastolic blood pressure, indicating silencing of UTX rescued aging-associated cardiac dysfunction. Aging-associated cardiac fibrosis is characterized by fibroblast activation and abundant extracellular matrix deposition, including collagen deposition and alpha smooth muscle actin activation. Silencing of UTX abolished collagen deposition and alpha smooth muscle actin activation, decreased serum transforming growth factor ß, blocked cardiac fibro blast s-to- myofi brobl asts trans-differentiation by elevation of cardiac resident mature fibroblast markers, TCF21, and platelet-derived growth factor receptor alpha, which are important proteins for maintaining cardiac fibroblast physiological function. In the mechanistic study, adeno-associated virus-UTX-small hairpin RNA blocked transforming growth factor ß-induced cardiac fibro blast s-to- myofi brobl asts trans-differentiation in isolated fibroblasts from 24-month-old mouse heart. The same results demonstrated as the in vivo study. CONCLUSIONS: Silencing of UTX attenuates aging-associated cardiac fibrosis via blocking cardiac fibroblasts-to-myofibroblasts transdifferentiation and consequently attenuates aging-associated cardiac dysfunction and cardiac fibrosis.

Rivaroxaban in heart failure patients with left ventricular thrombus: A retrospective study.

Background: The role of rivaroxaban in patients with heart failure (HF) combined with left ventricular (LV) thrombus remains unknown in current guideline-directed anticoagulant therapy. The aim of this study was to investigate the impact on clinical outcomes of rivaroxaban compared to vitamin K antagonists (VKAs) in patients with HF combined with LV thrombus. Methods: We retrospectively extracted clinical, echocardiographic and follow-up data of HF patients (all classifications) admitted at China-Japan Union Hospital of Jilin University from January 2017 to June 2021. A total of 198 patients with HF were identified with LV thrombus by echocardiography, 78 of them were managed with VKAs, 109 with rivaroxaban. Results: The median follow-up was 17.0 months (interquartile range: 6.0-24.0 months). High rates of major cardiovascular adverse events (MACEs) were observed in both the rivaroxaban and VKAs groups (49.5% vs. 57.7%). However, rivaroxaban versus VKAs observed a decrease in MACEs (adjusted HR:0.636; 95%CI:0.418-0.970; p = 0.035) and systemic embolism (4.6% vs. 12.8%; adjusted HR:0.318; 95%CI:0.108-0.933; p = 0.037; Gray's test p = 0.041) but was not found to have a benefit with regard to LV thrombus resolution (59.6% vs. 70.6%; adjusted HR: 1.303; 95% CI:0.898-1.890; p = 0.163; Gray's test p = 0.073). Additionally, there was no significant between-group difference in the rate of International Society on Thrombosis and Hemostasis (ISTH) bleeding events. Conclusion: Our data found that in populations with HF combined with LV thrombus, the overall prognosis in both the rivaroxaban and VKAs groups was catastrophic. Although rivaroxaban improved the prognosis to some extent, a considerable need remains for new treatments to improve their clinical course.

Prophylactic Rivaroxaban Therapy for Left Ventricular Thrombus After Anterior ST-Segment Elevation Myocardial Infarction.

OBJECTIVES: The aim of this study was to investigate the effects of rivaroxaban on left ventricle thromboprophylaxis in patients with anterior ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Anterior STEMI is associated with an increased risk of left ventricular thrombus (LVT) formation. The contemporary role of prophylactic rivaroxaban therapy remains unclear. METHODS: We randomly assigned 279 patients with anterior STEMI who had undergone primary percutaneous coronary intervention to receive, in a 1:1 ratio, low-dose rivaroxaban (2.5 mg twice daily for 30 days) and dual antiplatelet therapy (DAPT) or only DAPT. The primary efficacy outcome was the LVT formation within 30 days. Net clinical adverse events were assessed at 30 days and 180 days, including all-cause mortality, LVT, systemic embolism, rehospitalization for cardiovascular events, and bleeding. RESULTS: The addition of low-dose rivaroxaban to DAPT reduced LVT formation within 30 days compared with only DAPT (0.7% vs 8.6%; HR: 0.08; 95% CI: 0.01-0.62; P = 0.015; P < 0.001 for superiority). Net clinical adverse events were lower within 30 days in the rivaroxaban group versus those in the only DAPT group and remained relatively low throughout the follow-up period. There were no significant differences in bleeding events between the 2 groups in 30 days and 180 days. However, 1 case of intracranial hemorrhage (major bleeding) occurred in the rivaroxaban group within 30 days. CONCLUSIONS: Our results supported that the short-duration addition of low-dose rivaroxaban to DAPT could prevent LVT formation in patients with anterior STEMI following primary percutaneous coronary intervention. A larger multiple-institution study is necessary to determine the generalizability.

Rivaroxaban versus Vitamin K Antagonists (warfarin) based on the triple therapy for left ventricular thrombus after ST-Elevation myocardial infarction.

BACKGROUND: Left ventricular thrombus (LVT) can complicate ST-Elevation myocardial infarction (STEMI) and is associated with poor outcomes. Conventional triple anticoagulation [Vitamin K Antagonists (VKA) plus dual-antiplatelet therapy (DAPT)] is the first-line therapy for LVT after STEMI. In patients with LVT following STEMI, contemporary data of triple therapy with rivaroxaban are lacking. METHODS: We conducted a retrospective cohort study involving 1335 STEMI patients who underwent primary percutaneous coronary intervention (PCI). Among patients who developed LVT after STEMI, we observed differences in efficacy between rivaroxaban plus DAPT therapy and VKA plus DAPT. The time of LVT resolution was also evaluated, as well as net clinical adverse events, and rates of bleeding events. RESULTS: In 1335 patients with STEMI, a total of 77 (5.7%) developed LVT over the follow-up period (median 25.0 months). Of the patients diagnosed with LVT, 31 patients were started on triple therapy with VKA, 33 patients on triple therapy with rivaroxaban. There was a consistent similarity in LVT resolution with rivaroxaban application compared to VKA application during the follow-up period [HR (log-rank test) 1.57(95% CI 0.89-2.77), p = 0.096; Adjusted HR 1.70(95% CI 0.90-3.22), p = 0.104]. Triple therapy with rivaroxaban showed quicker resolution than with VKA (6 months: p = 0.049; 12 months: p = 0.044; 18 months: p = 0.045). Similar risks of ISTH bleeding were not significantly different between the 2 groups [VKA 9.7% vs Rivaroxaban 6.1%, Adjusted HR 0.48 (95% CI 0.73-3.20); p = 0.444)]. Fewer net adverse clinical events (NACE) were observed in the rivaroxaban group [VKA 58.1% vs Rivaroxaban 24.2%; HR (log-rank test) 0.31(95% CI 0.14-0.68), p = 0.003; Adjusted HR 0.23(95% CI 0.09-0.57), p = 0.001]. CONCLUSION: In the observational study, triple therapy with rivaroxaban has similar and quicker LVT resolution in patients with LVT after STEMI, compared with triple therapy with VKA, and perhaps was associated with a better clinical benefit. Larger sample sizes and randomized controlled trials are needed to confirm this observation.

Prognosis and New Predictors of Early Left-Ventricular Thrombus Following ST-Elevation Myocardial Infarction.

OBJECTIVE: In the current era of primary percutaneous coronary intervention (PPCI), the prognosis of the left ventricular thrombus (LVT) is not well assessed. METHODS: We performed a retrospective, single-center study of 1305 consecutive ST-segment-elevation myocardial infarction (STEMI) patients treated with PPCI. During a mean period of 27 months of follow-up, the major adverse cardiovascular and cerebrovascular events (MACCE) were recorded. RESULTS: The incidence of LVT (n = 47) was 3.60%. The independent risk factors of LVT included anterior STEMI, left ventricular (LV) aneurysm, reduced LV ejection fraction (LVEF), dilated LV end-diastolic dimension (LVEDD), and delayed door-to-balloon time (DTBT). During follow-up, LVT was an independent risk factor for MACCE [hazard ratio (HR)=3.46; 95% confidence interval (CI) = 2.23-3.38; P < 0.01]. Patients with LVT were more likely to have the following complications: heart failure (P < 0.001), embolic events (P = 0.034), and all-cause mortality (P = 0.020). Notably, the regression of LVT was not independently associated with those three adverse events (P > 0.05). CONCLUSION: In the era of PPCI, the presence of early LVT following STEMI was associated with adverse events. Furthermore, the prognosis of patients with LVT did not improve even if the LVT regressed. LVT was likely a generalized indicator of impaired cardiac performance, rather than the cause. This indicated that prophylactic therapy and identifying individuals with a high risk of developing LVT were of substantial importance.

Loeffler endocarditis with intracardiac thrombus: case report and literature review.

BACKGROUND: Loeffler endocarditis is a relatively rare and potentially life-threatening heart disease. This study aimed to identify the characteristic features of Loeffler endocarditis with intracardiac thrombus on a background of hypereosinophilic syndrome (HES). CASE PRESENTATION: We described a 57-year-old woman with Loeffler endocarditis and intracardiac thrombus initially presenting with neurological symptoms, who had an embolic stroke in the setting of HES. After cardiac magnetic resonance (CMR), corticosteroids and warfarin were administered to control eosinophilia and thrombi, respectively. During a 10-month follow-up, the patient performed relatively well, with no adverse events. We also systematically searched PubMed and Embase for cases of Loeffler endocarditis with intracardiac thrombus published until July 2021. A total of 32 studies were eligible and included in our analysis. Further, 36.4% of recruited patients developed thromboembolic complications, and the mortality rate was relatively high (27.3%). CMR was a powerful noninvasive modality in providing diagnostic and follow-up information in these patients. Steroids were administered in 81.8% of patients, achieving a rapid decrease in the eosinophil count. Also, 69.7% of patients were treated with anticoagulant therapy, and the thrombus was completely resolved in 42.4% of patients. Heart failure and patients not treated with anticoagulation were associated with poor outcomes. CONCLUSIONS: Cardiac involvement in HES, especially Loeffler endocarditis with intracardiac thrombus, carries a pessimistic prognosis and significant mortality. Early steroids and anticoagulation therapy may be beneficial once a working diagnosis is established. Further studies are needed to provide evidence-based evidence for managing this uncommon manifestation of HES.

Value of the platelet-to-lymphocyte ratio in the prediction of left ventricular thrombus in anterior ST-elevation myocardial infarction with left ventricular dysfunction.

BACKGROUND: The predictors of left ventricular thrombus (LVT) formation are not well defined in the contemporary era, especially in those patients at high risk. We aimed to evaluate whether the platelet/lymphocyte ratio (PLR) is valuable in the determination of LVT formation in patients with anterior ST-elevation myocardial infarction (STEMI) and left ventricular (LV) dysfunction. METHODS: The LVT group (n = 46) was identified from anterior STEMI patients with LV dysfunction who were treated with primary percutaneous coronary intervention (PCI) from January 2017 to December 2019 at the China-Japan Union Hospital of Jilin University. The no-LVT group (n = 92) were also selected from the same batch of patients and were age- and sex-matched to the patients with LVT. The PLR was determined at admission and was calculated as the ratio of the platelet count to the lymphocyte count using the complete blood count. The presence of LVT was determined by echocardiography. RESULTS: The PLR were significantly higher in patients with LVT than in no-LVT group (p = 0.001). In a receiver operator characteristic curve (ROC) analysis, using a cut-off value of 118.07 (AUC 0.673, 95% CI: 0.574-0.771, P = 0.001), the PLR could independently predict the occurrence of LVT. Multivariate analysis showed that an increased PLR (OR = 1.011, 95% CI: 1.004-1.018, P = 0.002), the presence of a left ventricular aneurysm (OR = 46.350, 95% CI: 5.659-379.615, P < 0.001) and increased DTBT (OR = 1.005, 95% CI: 1.001-1.009, P = 0.012) were independent predictors of LVT formation. CONCLUSIONS: In acute anterior STEMI patients with LV dysfunction, an increased PLR and DTBT and the presence of an LV aneurysm were independent predictors of LVT formation. A larger prospective study is warranted to evaluate this result. TRIAL REGISTRATION: This study was registered (May 4, 2019) on Chinese Clinical Trial Registry ( ChiCTR-DDD-17011214 ).

New Progress in Understanding the Cellular Mechanisms of Anti-arrhythmic Drugs.

Antiarrhythmic drugs are widely used, however, their efficacy is moderate and they can have serious side effects. Even if catheter ablation is effective for the treatment of atrial fibrillation and ventricular tachycardia, antiarrhythmic drugs are still important tools for the treatment of arrhythmia. Despite efforts, the development of antiarrhythmic drugs is still slow due to the limited understanding of the role of various ionic currents. This review summarizes the new targets and mechanisms of antiarrhythmic drugs.

Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles.

High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support - either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems - but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1-4nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures.

Noncrystalline-to-crystalline transformations in Pt nanoparticles.

We show that the noncrystalline-to-crystalline transition of supported Pt nanoparticles (NPs) in the subnanometer to nanometer size range is statistical in nature, and strongly affected by particle size, support, and adsorbates (here we use H2). Unlike in the bulk, a noncrystalline phase exists and is stable in small NPs, reflecting a general mesoscopic feature. Observations of >3000 particles by high-resolution transmission electron microscopy show a noncrystalline-to-crystalline transition zone that is nonabrupt; there is a size regime where disordered and ordered NPs coexist. The NP size at which this transition occurs is strongly dependent on both the adsorbate and the support, and this effect is general for late 5d transition metals. All results are reconciled via a statistical description of particle-support-adsorbate interactions.

Evolution of the structure and chemical state of Pd nanoparticles during the in situ catalytic reduction of NO with H2.

An in-depth understanding of the fundamental structure of catalysts during operation is indispensable for tailoring future efficient and selective catalysts. We report the evolution of the structure and oxidation state of ZrO(2)-supported Pd nanocatalysts (∼5 nm) during the in situ reduction of NO with H(2) using X-ray absorption fine-structure spectroscopy and X-ray photoelectron spectroscopy. Prior to the onset of the reaction (≤120 °C), a NO-induced redispersion of our initial metallic Pd nanoparticles over the ZrO(2) support was observed, and Pd(δ+) species were detected. This process parallels the high production of N(2)O observed at the onset of the reaction (>120 °C), while at higher temperatures (≥150 °C) the selectivity shifts mainly toward N(2) (∼80%). Concomitant with the onset of N(2) production, the Pd atoms aggregate again into large (6.5 nm) metallic Pd nanoparticles, which were found to constitute the active phase for the H(2)-reduction of NO. Throughout the entire reaction cycle, the formation and stabilization of PdO(x) was not detected. Our results highlight the importance of in situ reactivity studies to unravel the microscopic processes governing catalytic reactivity.

Structure, chemical composition, and reactivity correlations during the in situ oxidation of 2-propanol.

Unraveling the complex interaction between catalysts and reactants under operando conditions is a key step toward gaining fundamental insight in catalysis. We report the evolution of the structure and chemical composition of size-selected micellar Pt nanoparticles (∼1 nm) supported on nanocrystalline γ-Al(2)O(3) during the catalytic oxidation of 2-propanol using X-ray absorption fine-structure spectroscopy. Platinum oxides were found to be the active species for the partial oxidation of 2-propanol (<140 °C), while the complete oxidation (>140 °C) is initially catalyzed by oxygen-covered metallic Pt nanoparticles, which were found to regrow a thin surface oxide layer above 200 °C. The intermediate reaction regime, where the partial and complete oxidation pathways coexist, is characterized by the decomposition of the Pt oxide species due to the production of reducing intermediates and the blocking of O(2) adsorption sites on the nanoparticle surface. The high catalytic activity and low onset reaction temperature displayed by our small Pt particles for the oxidation of 2-propanol is attributed to the large amount of edge and corner sites available, which facilitate the formation of reactive surface oxides. Our findings highlight the decisive role of the nanoparticle structure and chemical state in oxidation catalytic reactions.

Solving the structure of size-selected Pt nanocatalysts synthesized by inverse micelle encapsulation.

The structure, size, and shape of gamma-Al(2)O(3)-supported Pt nanoparticles (NPs) synthesized by inverse micelle encapsulation have been resolved via a synergistic combination of imaging and spectroscopic tools. It is shown that this synthesis method leads to 3D NP shapes even for subnanometer clusters, in contrast to the raft-like structures obtained for the same systems via traditional deposition-precipitation methods. Furthermore, a high degree of atomic ordering is observed for the micellar NPs in H(2) atmosphere at all sizes studied, possibly due to H-induced surface reconstruction in these high surface area clusters. Our findings demonstrate that the influence of NP/support interactions on NP structure can be diminished in favor of NP/adsorbate interactions when NP catalysts are prepared by micelle encapsulation methods.