Platelet activation and thrombus formation relates to the presence of myocardial inflammation in patients with cardiomyopathy

Circulating c-Met-Expressing Memory T Cells Define Cardiac Autoimmunity

BACKGROUND

Autoimmunity is increasingly recognized as a key contributing factor in heart muscle diseases. The functional features of cardiac autoimmunity in humans remain undefined because of the challenge of studying immune responses in situ. We previously described a subset of c-mesenchymal epithelial transition factor (c-Met)-expressing (c-Met+) memory T lymphocytes that preferentially migrate to cardiac tissue in mice and humans.

METHODS

In-depth phenotyping of peripheral blood T cells, including c-Met+ T cells, was undertaken in groups of patients with inflammatory and noninflammatory cardiomyopathies, patients with noncardiac autoimmunity, and healthy controls. Validation studies were carried out using human cardiac tissue and in an experimental model of cardiac inflammation.

RESULTS

We show that c-Met+ T cells are selectively increased in the circulation and in the myocardium of patients with inflammatory cardiomyopathies. The phenotype and function of c-Met+ T cells are distinct from those of c-Met-negative (c-Met-) T cells, including preferential proliferation to cardiac myosin and coproduction of multiple cytokines (interleukin-4, interleukin-17, and interleukin-22). Furthermore, circulating c-Met+ T cell subpopulations in different heart muscle diseases identify distinct and overlapping mechanisms of heart inflammation. In experimental autoimmune myocarditis, elevations in autoantigen-specific c-Met+ T cells in peripheral blood mark the loss of immune tolerance to the heart. Disease development can be halted by pharmacologic c-Met inhibition, indicating a causative role for c-Met+ T cells.

CONCLUSIONS

Our study demonstrates that the detection of circulating c-Met+ T cells may have use in the diagnosis and monitoring of adaptive cardiac inflammation and definition of new targets for therapeutic intervention when cardiac autoimmunity causes or contributes to progressive cardiac injury.

Left ventricular thrombus in ischaemic heart disease: diagnosis, treatment, and gaps of knowledge

Although the management of ischaemic heart disease has markedly improved over the last decades, left ventricular thrombus remains a serious finding in patients with myocardial infarction. Routine diagnostic detection of left ventricular thrombus relies mainly on echocardiography; however, cardiac magnetic resonance has emerged as a method with higher diagnostic accuracy, while cardiac computed tomography angiography represents a valuable alternative modality. To reduce the left ventricular thrombus-associated morbidity and mortality, optimal selection of anticoagulation is warranted after balancing the risk of bleeding. In this review, we will discuss contemporary diagnostic modalities to detect left ventricular thrombus in ischaemic heart disease and summarize evidence on risk stratification and therapy. In addition, we propose a novel diagnosis, follow-up imaging, and treatment algorithm. Further, we identify knowledge gaps at different levels to address emerging research questions and to refine the design of future studies aiming to improve the management of patients in this clinical setting.

[Thromboembolic mask of severe lymphocytic myopericarditis: possibilities of clinical and morphological diagnostics and complex treatment]

This report presents a clinical case of a 57-year-old female patient who was admitted for dyspnea, productive cough, reduced left ventricular (LV) systolic function, and who had previously undergone thoracocentesis for significant pleural effusion. This case is a unique combination of lymphocytic myocarditis and massive intracardiac and ileo-caval thrombosis. Morphological verification of the diagnosis, that was necessary prior to the administration of immunosuppressive therapy due to the prothrombogenic effect of glucocorticoids, provided a justification for a basis therapy for myocarditis, which significantly improved the patient's condition.

Left ventricular thrombus on cardiovascular magnetic resonance imaging in non-ischaemic cardiomyopathy

AIMS

Case reports have described left ventricular (LV) thrombus in patients with non-ischaemic cardiomyopathy (NICM). We aimed to systematically study the characteristics, predictors, and outcomes of LV thrombus in NICM.

METHODS AND RESULTS

Forty-eight patients with LV thrombus detected on late gadolinium enhancement cardiovascular magnetic resonance imaging (LGE CMR) in NICM were compared with 124 patients with LV thrombus in ischaemic cardiomyopathy (ICM), and 144 matched patients with no LV thrombus in NICM. The performance of echocardiography for the detection of LV thrombus was compared between NICM and ICM. The 12-month incidence of embolism was compared between the three study groups. Independent predictors of LV thrombus in NICM were LV ejection fraction (LVEF) [hazard ratio (HR) 1.36 per 5% decrease; P = 0.002], LGE presence (HR 6.30; P < 0.001), and LGE extent (HR 1.33 per 5% increase; P = 0.001). Compared with patients with LV thrombus in ICM, those with LV thrombus in NICM had a 10-fold higher prevalence of thrombi in other cardiac chambers. The performance of echocardiography for the detection of LV thrombus was not different between NICM and ICM. The 12-month incidence of embolism associated with LV thrombus was not different between NICM and ICM (8.7% vs. 6.8%; P = 0.69) but both were higher compared with no LV thrombus in NICM (1.5%).

CONCLUSION

Independent predictors of LV thrombus in NICM were lower LVEF, LGE presence, and greater LGE extent. The 12-month incidence of embolism associated with LV thrombus in NICM was not different compared with LV thrombus in ICM.

Septal myectomy complicated by an embolic stroke in a patient with hypertrophic cardiomyopathy: a case report

Background

Hypertrophic cardiomyopathy is estimated to affect 1 out of every 500 adults in the USA. One of its main complications is left ventricular outflow obstruction, which may require surgical septal myectomy in severe cases. We report a rare complication of postoperative septal akinesis leading to thrombus formation presenting as an acute ischaemic stroke.

Case summary

A 48-year-old woman presented with acute stroke 2 years after surgical septal myectomy for hypertrophic obstructive cardiomyopathy. Diagnostic workup identified an intraventricular thrombus arising in the left ventricular outflow tract (LVOT). After comprehensive evaluation, it was determined that the thrombus development was a complication of the prior septal myectomy causing focal septal akinesis. Treatment with anticoagulation resulted in improvement of neurological symptoms and resolution of the intraventricular thrombus.

Discussion

This case illustrates the rarity and unusual presentation of an intracardiac thrombus that arises from septal myectomy site. A thrombus arising in the LVOT, which is characterized by high gradient laminar flow, is highly unusual. This suggests microscopic and macroscopic alteration in the ventricular septal wall structure, as evident by the septal wall akinesis seen on echocardiography. Recognition of this complication is critical to the selection of appropriate anticoagulation as secondary stroke prevention in these patients.

Management of inflammation in cardiovascular diseases

Cardiovascular disease is the leading cause of morbidity and mortality world-wide. Recently, the role of inflammation in the progression of diseases has significantly attracted considerable attention. In addition, various comorbidities, including diabetes, obesity, etc. exacerbate inflammation in the cardiovascular system, which ultimately leads to heart failure. Furthermore, cytokines released from specialized immune cells are key mediators of cardiac inflammation. Here, in this review article, we focused on the role of selected immune cells and cytokines (both pro-inflammatory and anti-inflammatory) in the regulation of cardiac inflammation and ultimately in cardiovascular diseases. While IL-1β, IL-6, TNFα, and IFNγ are associated with cardiac inflammation; IL-10, TGFβ, etc. are associated with resolution of inflammation and cardiac repair. IL-10 reduces cardiovascular inflammation and protects the cardiovascular system via interaction with SMAD2, p53, HuR, miR-375 and miR-21 pathway. In addition, we also highlighted recent advancements in the management of cardiac inflammation, including clinical trials of anti-inflammatory molecules to alleviate cardiovascular diseases.

Nano-scaled MTCA-KKV: for targeting thrombus, releasing pharmacophores, inhibiting thrombosis and dissolving blood clots in vivo

BACKGROUND

In vitro (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxyl-Lys(Pro-Ala-Lys)-Arg-Gly-Asp-Val (MTCA-KKV) adheres activated platelets, targets P-selectin and GPIIb/IIIa. This led to the development of MTCA-KKV as thrombus targeting nano-medicine.

METHODS

MTCA-KKV was characterized by nano-feature, anti-thrombotic activity, thrombolytic activity, thrombus target and targeting release.

RESULTS

In vivo 0.01 μmol/kg of MTCA-KKV formed nano-particles less than 100 nm in diameter, targeted thrombus, released anti-thrombotic and thrombolytic pharmacophores, prevented thrombosis and dissolved blood clots.

CONCLUSION

Based on the profiles of targeting thrombus, targeting release, inhibiting thrombosis and dissolving blood clots MTCA-KKV is a promising nano-medicine.

Heptapeptide-based modification leading to enhancing the action of MTCA on activated platelets, P-selectin, GPIIb/IIIa

AIM

The modification of platelet inhibitor to enhance its targeting capacity toward platelets is of clinical importance. Thus, (1R, 3S)-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (MTCA), a platelet inhibitor, was modified with Lys(Pro-Ala-Lys)-Arg-Gly-Asp-Val (KKV), platelet targeting peptide, to form MTCA-KKV.

MATERIALS & METHODS

MTCA and MTCA-KKV were synthesized to identify the effect of KKV modification on MTCA and platelets.

RESULTS

Atomic force microscopy imaged MTCA-KKV effectively accumulated on activated platelets. UV spectra showed that MTCA-KKV concentration dependently changed P-selectin and GPIIb/IIIa conformations. For platelet aggregation, the IC₅₀ of MTCA-KKV was approximately 1/10 folds of MTCA.

CONCLUSION

KKV modification led to forming MTCA-KKV that is superior to MTCA in terms of accumulating on activated platelets, targeting P-selectin and GPIIb/IIIa and inhibiting platelet aggregation. MTCA-KKV could be a promising lead for further investigation.

Vascular Cognitive Impairment Linked to Brain Endothelium Inflammation in Early Stages of Heart Failure in Mice

BACKGROUND

Although advanced heart failure (HF) is a clinically documented risk factor for vascular cognitive impairment, the occurrence and pathomechanisms of vascular cognitive impairment in early stages of HF are equivocal. Here, we characterize vascular cognitive impairment in the early stages of HF development and assess whether cerebral hypoperfusion or prothrombotic conditions are involved.

METHODS AND RESULTS

Tgαq*44 mice with slowly developing isolated HF triggered by cardiomyocyte-specific overexpression of G-αq*44 protein were studied before the end-stage HF, at the ages of 3, 6, and 10 months: before left ventricle dysfunction; at the stage of early left ventricle diastolic dysfunction (with preserved ejection fraction); and left ventricle diastolic/systolic dysfunction, respectively. In 6- to 10-month-old but not in 3-month-old Tgαq*44 mice, behavioral and cognitive impairment was identified with compromised blood-brain barrier permeability, most significantly in brain cortex, that was associated with myelin sheet loss and changes in astrocytes and microglia. Brain endothelial cells displayed increased E-selectin immunoreactivity, which was accompanied by increased amyloid-β1-42 accumulation in piriform cortex and increased cortical oxidative stress (8-OHdG immunoreactivity). Resting cerebral blood flow measured by magnetic resonance imaging in vivo was preserved, but ex vivo NO-dependent cortical arteriole flow regulation was impaired. Platelet hyperreactivity was present in 3- to 10-month-old Tgαq*44 mice, but it was not associated with increased platelet-dependent thrombogenicity.

CONCLUSIONS

We report for the first time that vascular cognitive impairment is already present in the early stage of HF development, even before left ventricle systolic dysfunction. The underlying pathomechanism, independent of brain hypoperfusion, involves preceding platelet hyperreactivity and brain endothelium inflammatory activation.

Prazosin protects myocardial cells against anoxia-reoxygenation injury via the extracellular signal‑regulated kinase signaling pathway

Ischemic heart disease (including coronary arterial atherosclerosis, or vascular cavity stenosis or occlusion) remains the leading cause of disease-associated mortality worldwide. Prazosin, a receptor blocker of postsynaptic adrenaline, is essential in expanding peripheral arteries, which decreases peripheral vascular resistance, and regulates anti-hypertensive action. However, the mechanisms underlying the effects of prazosin have not been fully elucidated. The aim of the present study was to investigate the protective effects of prazosin on myocardial cells against anoxia-reoxygenation injury in a mouse model. The regulatory effects of prazosin on blood lipid levels and blood pressure were investigated in experimental mice. Furthermore, inflammation responses and oxidative stress in myocardial cells were analyzed in mice treated with prazosin. Apoptotic myocardial cells were investigated in experimental mice treated with prazosin. In addition, apoptotic gene expression levels were evaluated in myocardial cells. Extracellular signal-regulated kinase (ERK) expression and phosphorylation was investigated in myocardial cells in mice with anoxia-reoxygenation injury following prazosin treatment. The activity and expression levels of nuclear factor of activated T cells (NF-AT), activator protein 1 (AP-1) and necrosis factor (NF)-κB were observed in myocardial cells. Furthermore, histological analyses were performed to investigate the benefits of prazosin treatment on anoxia-reoxygenation injury. The results of the present study identified that prazosin decreased the expression levels of inflammatory factors, interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10 and IL-1 in the serum of mice exhibiting hypoxia/reoxygenation injury. Oxidative stress was observed to be improved and the apoptosis rate was decreased in myocardial cells in anoxia-reoxygenation injury model mice treated with prazosin. ERK expression and phosphorylation was upregulated, and expression levels of NF-AT, AP-1 and NF-κB were downregulated in the myocardial cells of mice treated with prazosin. Blood lipid levels and blood pressure of the anoxia-reoxygenation injury model mice were markedly improved following treatment with prazosin. Histological analysis indicated that the area, circumference fragmentation and segmentation of myocardial cells were significantly improved following prazosin treatment. Thus, these results indicate that prazosin treatment decreases inflammation responses, oxidative stress, and apoptosis of myocardial cells via regulation of the ERK signaling pathway. The findings indicate that prazosin may present as a potential therapeutic agent for the treatment of hypoxia/reoxygenation injury.

IQCA-TAVV: To explore the effect of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 on deep venous thrombosis

Deep vein thrombosis (DVT) associates with considerable morbidity, functional disability and mortality. Due to the lack of suitable inhibitor the correlation of various factors in DVT onset remains unknown. In this context we analyzed the structure of anti-platelet aggregation agent, P-selectin down-regulator, GPIIb/IIIa down-regulator and anti-inflammatory agent, thereby designed N-(3S-1,2,3,4-tetrahydroisoquinoline-3-carbonyl)- Thr-Ala-Arg-Gly-Asp(Val)-Val (IQCA-TAVV) as an inhibitor of DVT to receive evaluations. The docking predicted that IQCA-TAVV can target P-selectin and GPIIb/IIIa. The UV showed that IQCA-TAVV can act on P-selectin and GPIIb/IIIa. ELISA indicated that IQCA-TAVV concentration dependently inhibited activated platelets to express P-selectin and GPIIb/IIIa, and the minimal effective concentration was 1 nM. IC50 of IQCA-TAVV against platelet aggregation induced by arachidonic acid, adenosine diphosphate and platelet activating factor fell within a range of 0.13 nM to 0.30 nM. In vivo IQCA-TAVV dose-dependently inhibited venous thrombosis and the minimal effective dose was 1 nmol/kg. On ear edema model the anti-inflammation activity of 10 nmol/kg IQCA-TAVV equaled that of 1.1mmol/kg aspirin. The concentration of IL-2, IL-6 and IL-8 in the serum of the ear edema mice were also significantly decreased by 10 nmol/kg IQCA-TAVV. Even at 1 μmol/kg of dose IQCA-TAVV still did not injure the kidney, the liver, and the nerves of healthy mice. Thereby IQCA-TAVV depicts a relationship of three levels (inhibiting platelet activation, targeting externalized membrane receptor, decreasing serum inflammatory factor) for the down-regulation of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 in DVT.