Cav-1 Protein Levels in Serum and Infarcted Brain Correlate with Hemorrhagic Volume in a Mouse Model of Thromboembolic Stroke, Independently of Rt-PA Administration

Thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) is currently the only FDA-approved drug for acute ischemic stroke. However, its administration is still limited due to the associated increased risk of hemorrhagic transformation (HT). rt-PA may exacerbate blood-brain barrier (BBB) injury by several mechanisms that have not been fully elucidated. Caveolin-1 (Cav-1), a major structural protein of caveolae, has been linked to the endothelial barrier function. The effects of rt-PA on Cav-1 expression remains largely unknown. Here, Cav-1 protein expression after ischemic conditions, with or without rt-PA administration, was analyzed in a murine thromboembolic middle cerebral artery occlusion (MCAO) and in brain microvascular endothelial bEnd.3 cells subjected to oxygen/glucose deprivation (OGD). Our results show that Cav-1 is overexpressed in endothelial cells after ischemia in both models. rtPA significantly reduced Cav-1 expression and increases pCav-1/Cav-1 ratio in bEnd.3 cells, but not in the in vivo model. In addition, we first show that increased Cav-1 immunoreactivity in the infarcted area and Cav-1 serum levels are positively correlated at 24 h post-MCAO. Interestingly, Cav-1 expression in infarcted area and baseline serum Cav-1 levels negatively correlate with hemorrhagic volume, supporting a protective role of Cav-1 in cerebral ischemia and pointing to a potential usefulness of baseline serum Cav-1 levels as predictor of hemorrhagic volume, independently of rt-PA administration.

Micro-biopsy for detection of gene expression changes in ischemic swine myocardium: A pilot study

Micro-endomyocardial biopsy (micro-EMB) is a novel catheter-based biopsy technique, aiming to increase flexibility and safety compared to conventional EMB. The technique was developed and evaluated in healthy swine. Therefore, the ability to detect disease related tissue changes could not be evaluated. The aim of the present pilot study was to investigate the ability to detect disease related gene expression changes using micro-EMB. Myocardial infarction was induced in three swine by coronary artery balloon occlusion. Micro-EMB samples (n = 164) were collected before, during, and after occlusion. RNA-sequencing was performed on 85 samples, and 53 of these were selected for bioinformatic analysis. A large number of responding genes was detected from the infarcted area (n = 1911). The early responding genes (n = 1268) were mostly related to apoptosis and inflammation. There were fewer responding genes two days after infarction (n = 6), which were related to extra-cellular matrix changes, and none after 14 days. In contrast to the infarcted area, samples harvested from a non-infarcted myocardial region showed considerably fewer regulated genes (n = 33). Deconvolution analysis, to estimate the proportion of different cell types, revealed a higher proportion of fibroblasts and a reduced proportion of cardiomyocytes two days after occlusion compared to baseline (p < 0.02 and p < 0.01, respectively. S5 File). In conclusion, this pilot study demonstrates the capabilities of micro-EMB to detect local gene expression responses at an early stage after ischemia, but not at later timepoints.

Role of Adenosine and Purinergic Receptors in Myocardial Infarction: Focus on Different Signal Transduction Pathways

Myocardial infarction (MI) is a dramatic event often caused by atherosclerotic plaque erosion or rupture and subsequent thrombotic occlusion of a coronary vessel. The low supply of oxygen and nutrients in the infarcted area may result in cardiomyocytes necrosis, replacement of intact myocardium with non-contractile fibrous tissue and left ventricular (LV) function impairment if blood flow is not quickly restored. In this review, we summarized the possible correlation between adenosine system, purinergic system and Wnt/β-catenin pathway and their role in the pathogenesis of cardiac damage following MI. In this context, several pathways are involved and, in particular, the adenosine receptors system shows different interactions between its members and purinergic receptors: their modulation might be effective not only for a normal functional recovery but also for the treatment of heart diseases, thus avoiding fibrosis, reducing infarcted area and limiting scaring. Similarly, it has been shown that Wnt/β catenin pathway is activated following myocardial injury and its unbalanced activation might promote cardiac fibrosis and, consequently, LV systolic function impairment. In this regard, the therapeutic benefits of Wnt inhibitors use were highlighted, thus demonstrating that Wnt/β-catenin pathway might be considered as a therapeutic target to prevent adverse LV remodeling and heart failure following MI.

Prospective Observational Study of Safety of Early Treatment with Edoxaban in Patients with Ischemic Stroke and Atrial Fibrillation (SATES Study)

New direct oral anticoagulants are recommended for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). However, no data are available regarding the optimal time to start oral anticoagulation after acute stroke. The aim of our study was to evaluate the occurrence of symptomatic bleedings within 90 days from acute cardioembolic stroke in patients who received early treatment with Edoxaban. The study was conducted according to an observational prospective uncontrolled design. Secondary endpoints were the incidence of major bleeding (MB), hemorrhagic transformation within the first week of Edoxaban treatment, minor bleeding, and recurrent stroke. We included patients with Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≥ 6, NVAF, no previous treatment with any other anticoagulant, preserved swallowing function. Patients with estimated Glomerular Filtration Rate < 50 mL/min, body weight < 60 kg, receiving cyclosporine, dronedarone, erythromycin, ketoconazole, or previous treatment with any other anticoagulant were excluded. We enrolled 75 elderly patients with moderate disability. We did not observe any symptomatic intracranial bleeding or recurrent stroke after 3 months of treatment with early administration of Edoxaban, while two gastrointestinal MB, and 11 minor bleedings were reported. Asymptomatic bleeding was evaluated with a brain Magnetic Resonance Imaging performed 5 days after starting anticoagulant treatment with Edoxaban. Specifically, we observed small petechiae in 12% of the patients, confluent petechiae in 6.6% of the patients, and small hematoma of the infarcted area in 2.7% of the patients. No intralesional hematoma or hemorrhagic lesion outside the infarcted area were observed. According to our data, the early use of Edoxaban seems to be safe in patients after cardioembolic stroke. However, due to the small size of the study sample, and the short follow-up period, further studies are needed.

Tongxinluo promotes axonal plasticity and functional recovery after stroke

BackgroundThe aim of this study was to investigate the neural plasticity in contralesional cortex and the effects of tongxinluo (TXL) in cerebral ischemic rats.MethodologyWe used stroke-prone renovascular hypertensive (RHRSP) cerebral ischemia rat models to study the effect of TXL and the underlying mechanisms. We performed foot-fault and beam-walking tests to evaluate the motor function of rats after cortical infarction. Biotinylated dextran amine (BDA) was used to track axonal sprouting and neural connections.ResultsTXL enhanced the recovery of motor function in cerebral infarction rats. TXL increased axonal sprouting in the peri-infarcted area but not in the corpus callosum, indicating in situ origination instead of crossing between cortical hemispheres through the corpus callosum. TXL promoted the sprouting of corticospinal axons into the denervated side of spinal gray matter. The synaptophysin (SYN)-positive intensity in the peri-infarcted area of TXL-treated group was greater than that in the vehicle group. We observed co-localization of SYN with BDA-positive fibers in the denervated spinal cord gray matter in the TXL group, suggesting that axonal remodeling and synaptic connections were promoted by TXL.ConclusionTXL may promote the recovery of neurological function by promoting the axonal remodeling and synapse formation of motor neuronal fibers after focal cortical infarction in hypertensive rats.

Modified Taohong Siwu Decoction Improved Heart Function After Myocardial Infarction by Inhibiting Inflammatory Factor and Promoting Chemotactic and Pro-Angiogenic Factors

BackgroundTraditional Chinese medicine has been applied to prevent and treat myocardial infarction (MI) in the clinic for a long history. We recently found that Taohong Siwu decoction (THSWD) exerted a beneficial effect on heart function after MI through improving the local hostile microenvironment. However, the improvement of cardiac function after THSWD administration was moderate. In this study, four Chinese medicine herbs, which have the properties of warming Yang or removing phlegm, were added into THSWD to constitute a new and multifunctional Chinese herbal compound, named modified THSWD (MTHSWD). MethodsA rat model of MI was established by the ligation of left anterior descending coronary artery and MTHSWD was intragastrically administered for 2 weeks. The heart function was examined by echocardiography, cell apoptosis was detected by TUNEL staining and the infarct size was determined by Masson's trichrome staining. The expressions of cytokines, including chemotactic and inflammatory factors, were examined by ELISA in the infarcted myocardium and serum. The level of p-Akt and VEGF in the damaged myocardial tissues was further detected by Western blot. ResultsMTHSWD improved heart function and decreased infarct size and collagen deposition in the infarcted area. In addition, MTHSWD increased the expression of cTnT and Cx43, reduced cell apoptosis in the infarcted area by activating Akt signal and promoted angiogenesis by increasing the expression of VEGF. Interestingly, MTHSWD significantly increased the level of IGF-1, SDF-1 and TNF-α, and significantly reduced the expression of IL-1β in the infarcted myocardium. MTHSWD could also significantly increase the expression of IGF-1, SDF-1 and SCF in the serum. ConclusionsMTHSWD reduced cell apoptosis, promoted angiogenesis and improved heart function after MI probably through the downregulation of inflammatory factor IL-1β, upregulation of chemotactic factors SDF-1 and SCF as well as pro-angiogenic factor VEGF, and activation of Akt signaling pathway.

Influence of the distribution of fibrosis within an area of myocardial infarction on wave propagation in ventricular tissue

The presence of fibrosis in heart tissue is strongly correlated with an incidence of arrhythmia, which is a leading cause of sudden cardiac death (SCD). However, it remains incompletely understood how different distributions, sizes and positions of fibrotic tissues contribute to arrhythmogenesis. In this study, we designed 4 different ventricular models mimicking wave propagation in cardiac tissues under normal, myocardial infarction (MI), MI with random fibrosis and MI with gradient fibrosis conditions. Simulation results of ideal square tissues indicate that vulnerable windows (VWs) of random and gradient fibrosis distributions are similar with low levels of fibrosis. However, with a high level of fibrosis, the VWs significantly increase in random fibrosis tissue but not in gradient fibrosis tissue. In addition, we systematically analyzed the effects of the size and position of fibrosis tissues on VWs. Simulation results show that it is more likely for a reentry wave to appear when the length of the infarcted area is greater than 25% of the perimeter of the ventricle, when the width is approximately half that of the ventricular wall, or when the infarcted area is attached to the inside or outside of the ventricular wall.

P2563Effects of rivaroxaban on cardiac remodeling after experimental myocardial infarction in mice

Background Rivaroxaban, a direct activated factor X (FXa) inhibitor, has been established for prevention and treatment of arterial and venous thrombosis. Although FXa plays an important role in thrombosis, FXa also involves in inflammation via the protease-activated receptor (PAR)-1 and PAR-2 pathway. We assessed the hypothesis that rivaroxaban might protect cardiac remodeling after myocardial infarction (MI) in mice. Methods MI was induced in wild-type mice by permanent ligation of the left anterior descending coronary artery. At 1 day after MI, mice were randomly assigned to the rivaroxaban and vehicle groups. In the rivaroxaban group, the mice were provided with regular chow diet including rivaroxaban (2400ppm) after the randomization. We evaluated the cardiac function by echocardiography, expression of mRNA and protein in the infarcted and non-infarcted area 7 days after MI. Furthermore, we measured infarct size, infiltration of inflammatory cells by pathological analysis 7 days after MI. Results The fractional shortening (%FS) and Interventricular Septal thickness in diastole (IVSTd) was significantly improved 7 days after MI in the rivaroxaban group compared with the vehicle group (%FS, p=0.01; IVSTd, p=0.013). As for pathological analysis, rivaroxaban decreased infarct size (p=0.026) and the number of infiltrated macrophages in the non-infarcted area (p=0.011) compared with vehicle. The mRNA expression in tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β in the infarcted area and atrial natriuretic peptide (ANP) in the non-infarcted area was significantly lower in the rivaroxaban group compared with the vehicle (TNF-α, p=0.015; TGF-β, p=0.019; ANP, p=0.012). PAR-1 and PAR-2 mRNA expression in the infarcted area significantly decreased 7 days after MI in the rivaroxaban group compared with the vehicle (PAR-1, p=0.005; PAR-2, p=0.037). Furthermore, western blot analysis demonstrated that the phosphorylation of Extracellular Signal-regulated Kinase (ERK) and c-Jun N-terminal Kinase (JNK) in the non-infarcted area significantly decreased 7 days after MI in the rivaroxaban group compared with the vehicle (ERK, p=0.015; JNK, p=0.002). Conclusions The present study showed that rivaroxaban protected against cardiac dysfunction, probably due to the suppression of PAR-mediated increase of pro-inflammatory cytokines post-MI. Rivaroxaban might be potentially effective for improving the cardiac remodeling after MI. Acknowledgement/Funding This study was supported in part by trust-research grant from Bayer Yakuhin, Ltd.

P121918F-FDG perfusion-metabolism mismatch 3 days after acute myocardial infarction predicts worse outcome: molecular glucose steel phenomenon visualized by hybrid PET-MRI images

Background The disturbance of cardiac energy substrate metabolism has a decisive role in the pathogenesis of adverse cardiac remodeling and heart failure. Under normoxic conditions, the free fatty acid metabolism is the predominant pathway by providing the highest energy per substrate molecule. Severe myocardial hypoxia leads to a switch from beta-oxidation to glucose metabolism to increase the ATP production per oxygen molecule. This metabolic disorder appears as perfusion-metabolism mismatch in 18F-fluorodeoxyglucose (18F-FDG) PET images, as increased 18F-FDG uptake in the under-perfused hypoxic myocardial area. Purpose The aim of our study was to evaluate the simultaneous perfusion, metabolism and function of the ischemic heart by hybrid 18F-FDG-PET-cMRI with late enhancement images in a translation animal model of heart failure. Methods Under general anesthesia, closed chest reperfused acute myocardial infarction (AMI) was induced in 36 domestic pigs by 90 min occlusion of the mid left anterior descending artery with a percutaneous intracoronary balloon, followed by reperfusion. Three days and 1 month after AMI, after 12h fasting, 18F-FDG-PET-cMRI were performed by using standardized acquisition protocols (n=30). Cardiac functional parameter, such as ejection fraction (EF), end-diastolic volume (EDV), infarct size, and mean tracer uptake of the infarcted area were quantitatively assessed. Six animals were euthanized after the 3-day 18F-FDG-PET-cMRI images to elaborate the differences in gene expression patterns in animals with perfusion-metabolic mismatch by using next generation sequencing (NGS) and pathway network analyses. Results Eight (group Mismatch) of the 30 animals (group Match) with 1-month follow-up showed high 18F-FDG uptake in the infarcted area (perfusion-metabolism mismatch) at the 3-day 18F-FDG-PET-cMRI-LE images (Figure). The animals in the Mismatch group had significantly lower EF at 3 days (34±8.8 vs 42±3%) and at the 1-month follow-up (35.8±6 vs 43±6.6%) and larger infarct size at day 3 (26.6±6.6 vs 22.1±4.4%) and 1 month (28±5.4 vs 20.3±4.3%) with higher EDV at 1 month. Mean tracer uptake of the infarcted area was significantly reduced in the Mismatch group at 1 month (56±23.1 vs 64.7±13.2%). NGS revealed downregulation of the cholesterol metabolism pathway, and upregulation of carbohydrate derivative catabolism pathway with highly activated innate immune system and genes responsible for cytokine activation in the infarcted area 3 days post-AMI in the Mismatch group, which explains the paradox high 18F-FDG tracer uptake in the infarction zone. Accordingly, the high energy demand of the severe hypoxic area led to “glucose steel phenomenon” at the molecular level, subtracting the 18F-FDG from the normally perfused non-ischemic myocardial regions. Conclusions 18F-FDG-glucose perfusion-metabolism mismatch early after AMI visualized by hybrid 18F-FDG-PET-MRI images predict development of LV adverse remodeling. Acknowledgement/Funding Fibrotarget EU Grant Nr 602904

Therapeutic Effects in a Transient Middle Cerebral Artery Occlusion Rat Model by Nose-To-Brain Delivery of Anti-TNF-Alpha siRNA with Cell-Penetrating Peptide-Modified Polymer Micelles

We previously reported that siRNA delivery to the brain is improved by the nose-to-brain delivery route and by conjugation with polyethylene glycol-polycaprolactone (PEG-PCL) polymer micelles and the cell-penetrating peptide, Tat (PEG-PCL-Tat). In this study, we evaluated the nose-to-brain delivery of siRNA targeting TNF-α (siTNF-α) conjugated with PEG-PCL-Tat to investigate its therapeutic effects on a transient middle cerebral artery occlusion (t-MCAO) rat model of cerebral ischemia-reperfusion injury. Intranasal treatment was provided 30 min after infarction induced via suturing. Two hours after infarction induction, the suture was removed, and blood flow was released. At 22 h post-reperfusion, we assessed the infarcted area, TNF-α production, and neurological score to determine the therapeutic effects. The infarcted area was observed over a wide range in the untreated group, whereas shrinkage of the infarcted area was observed in rats subjected to intranasal administration of siTNF-α with PEG-PCL-Tat micelles. Moreover, TNF-α production and neurological score in rats treated by intranasal administration of siTNF-α with PEG-PCL-Tat micelles were significantly lower than those in untreated and naked siTNF-α-treated rats. These results indicate that nose-to-brain delivery of siTNF-α conjugated with PEG-PCL-Tat micelles alleviated the symptoms of cerebral ischemia-reperfusion injury.