The effects of direct thrombin inhibition with dabigatran on plaque formation and endothelial function in apolipoprotein E-deficient mice

Clinical outcomes and anticoagulation therapy in elderly non-valvular atrial fibrillation and heart failure patients

AIMS

Atrial fibrillation (AF) and heart failure (HF) often coexist. Older age is strongly associated with stroke, HF, and mortality. The association between coexistence of HF and a risk of clinical outcomes and the effectiveness of anticoagulation therapy including direct oral anticoagulants (DOACs) in elderly patients with AF and HF have not been investigated. We aimed to evaluate 2 years of outcomes and to elucidate the efficacy of DOACs or warfarin in elderly AF patients in the All Nippon AF In the Elderly (ANAFIE) Registry with and without a history of HF.

METHODS AND RESULTS

The ANAFIE Registry is a multicentre, prospective observational study following elderly non-valvular AF patients aged ≥75 years for 2 years. Hazard ratios (HRs) were calculated based on the presence or absence of an HF diagnosis and DOAC or warfarin use at enrolment. Among 32 275 eligible patients, 12 116 (37.5%) had been diagnosed with HF. Patients with HF had significantly higher rates of HF hospitalization or cardiovascular death (HR 1.94, P < 0.001), cardiovascular events (HR 1.59, P < 0.001), cardiovascular death (HR 1.49, P < 0.001), all-cause death (HR 1.32, P < 0.001), and net clinical outcome including stroke/systemic embolism, major bleeding, and all-cause death (HR 1.23, P < 0.001), compared with those without HF; however, HRs for stroke/systemic embolism (HR 0.96, P = 0.56) and major bleeding (HR 1.14, P = 0.13) were similar. DOAC use was associated with a low risk of stroke/systemic embolism (HR 0.86, P = 0.19 in HF; HR 0.79, P = 0.016 in non-HF; P for interaction = 0.56), major bleeding (HR 0.71, P = 0.008 in HF; HR 0.75, P = 0.016 in non-HF; P for interaction = 0.74), HF hospitalization or cardiovascular death (HR 0.81, P < 0.001 in HF; HR 0.78, P < 0.001 in non-HF; P for interaction = 0.26), cardiovascular events (HR 0.83, P < 0.001 in HF; HR 0.82, P = 0.001 in non-HF; P for interaction = 0.65), cardiovascular death (HR 0.84, P = 0.12 in HF; HR 0.75, P = 0.035 in non-HF; P for interaction = 0.18), all-cause death (HR 0.89, P = 0.082 in HF; HR 0.80, P = 0.001 in non-HF; P for interaction = 0.091), and net clinical outcome (HR 0.88, P = 0.019 in HF; HR 0.81, P < 0.001 in non-HF; P for interaction = 0.21) compared with warfarin, irrespective of the presence or absence of HF. Analysis using the propensity score matching method showed similar associations.

CONCLUSIONS

Non-valvular AF patients aged ≥75 years with a history of HF had higher risks of cardiovascular events and mortality. DOACs were favourable to warfarin regardless of the coexistence of HF. These results might encourage the use of DOACs in elderly patients with non-valvular AF with or without HF.

Cardiac and renal outcomes of direct oral anticoagulants in patients with atrial fibrillation

BACKGROUND

Oral anticoagulation therapy with warfarin or direct oral anticoagulants (DOACs) is the mainstay for stroke prevention in patients with non-valvular atrial fibrillation (AF). The DOACs might have a lower risk of declining renal function than warfarin. This study aimed to compare renal outcomes among rivaroxaban, edoxaban, dabigatran, and warfarin.

METHOD

This cohort study identified 2203 adults with AF who started anticoagulation therapy between 1 July 2013 and 31 December 2020, in a clinical database at a single centre. Inverse probability of treatment weighting was adopted to balance baseline characteristics among four anticoagulants treatment groups. The primary outcome was a composite of cardiac and renal outcomes, involving a ≥30% decline in estimated glomerular filtration rate (eGFR), renal failure and cardiovascular death.

RESULTS

After propensity score weighting, dabigatran was associated with significantly lower risks of a ≥30% decline in eGFR (hazard ratio [HR]: .69, 95% confidence interval [CI]: .497-.951, p = .0237), doubling of the serum creatinine level (HR: .49, 95% CI: .259-.927, p = .0282) and the cardiac and renal outcome composite (HR: .67, 95% CI: .485-.913, p = .0115) than warfarin. Rivaroxaban and edoxaban did not show significant protective effects on renal outcomes compared to warfarin.

CONCLUSION

In this study, patients treated with dabigatran had significantly reduced risks of declining renal function and composite cardiac and renal events than those treated with warfarin. However, rivaroxaban and edoxaban were not associated with lower risks of any renal outcomes than warfarin. More studies are warranted to investigate and compare the impact of renal function between different DOACs in patients with AF.

Anti-thrombotics and major adverse cardiovascular events in anti-phospholipid syndrome: a cross-sectional study using the 2016-2018 National Inpatient Sample database

OBJECTIVE

This study assessed the relationship between anti-thrombotics and major adverse cardiovascular events (MACE) in patients with anti-phospholipid syndrome (APS).

METHOD

We included 13 947 subjects with APS from the National (Nationwide) Inpatient Sample (NIS) database for 2016-2018, and collected relevant covariates and demographic data using ICD-10 codes. Our two primary outcomes were MACE and death. We performed multivariate logistic regression analysis to assess the impact of various anti-thrombotic regimens on MACE/death in our primary cohort and high-risk subgroups.

RESULTS

Patients on anti-coagulants had significantly reduced odds of MACE [odds ratio (OR) 0.68, 95% confidence interval (CI) 0.62-0.76, p < 0.001] as well as each of its subcomponents. Those not on any anti-coagulants had significantly increased odds of MACE (OR 1.47, 95% CI 1.24-1.72, p < 0.001). No significant association was found between anti-platelet use and the odds of MACE (p > 0.05). Patients on anti-coagulants were the only class that appeared to have a mortality benefit with reduced odds for death (OR 0.64, 95% CI 0.49-0.84, p = 0.001). In the subgroups at higher risk for MACE (those with atrial fibrillation and thrombocytopenia), full anti-coagulation therapy was also the only anti-thrombotic class that significantly affected the odds of MACE, with a protective effect on MACE, but had no mortality benefit.

CONCLUSION

Patients with APS are most likely to benefit from anti-coagulant therapy in reducing MACE. Furthermore, anti-platelets alone or in combination with anti-coagulants are probably not beneficial in MACE reduction and may even increase risk.

The Complementary Effects of Dabigatran Etexilate and Exercise Training on the Development and Stability of the Atherosclerotic Lesions in Diabetic ApoE Knockout Mice

Aim: To determine the complementary effects of dabigatran etexilate (DE), exercise training (ET), and combination (DE + ET) on the development and stability of the atherosclerotic lesions in diabetic apoE knockout (apoE-/-) mice. Methods: In 48 male apoE-/- diabetic mice, streptozotocin (STZ) was induced for 5 consecutive days. Mice received a high-fat diet (HFD) for 8 weeks and then were randomized into four groups (1. Control/CG, 2. DEG: HFD with DE, 3. ETG: ET on treadmill, 4. DE + ETG: combination DE and ET treatment). At the end of the eighth week, all mice were euthanatized and morphometry of the aortic lesions at the level of aortic valve was obtained. Collagen, elastin, MCP-1, TNF-a, matrix metalloproteinases (MMP-2,-3,-9), and TIMP-1 concentrations within plaques at the aortic valve were determined. Results: All active groups had significantly smaller aorta stenosis (DEG:7.9 ± 2.2%, ETG:17.3 ± 5.3%, DE + ETG:7.1 ± 2.7%) compared to CG (23.3 ± 5.5% p < 0.05), reduced the relative intra-plaque content of MCP-1, macrophages, MMP-3, and MMP-9, and considerably increased collagen, elastin, and TIMP-1 (p < 0.05). Group 4 showed the most pronounced results (p < 0.05). Both DEG and DE + ETG significantly reduced MMP-2 and TNF-a concentrations compared to ETG and CG (p < 0.010). Conclusion: DE and ET treatment of diabetic apoE-/- mice resulted in complementary amelioration of atherosclerotic lesions development and stability, mediated by the anti-inflammatory modulation of both DE and ET.

Distinct pleiotropic effects of direct oral anticoagulants on cultured endothelial cells: a comprehensive review

Direct Oral Anticoagulants (DOACs) have simplified the treatment of thromboembolic disease. In addition to their established anticoagulant effects, there are indications from clinical and preclinical studies that DOACs exhibit also non-anticoagulant actions, such as anti-inflammatory and anti-oxidant actions, advocating overall cardiovascular protection. In the present study, we provide a comprehensive overview of the existing knowledge on the pleiotropic effects of DOACs on endothelial cells (ECs) in vitro and their underlying mechanisms, while also identifying potential differences among DOACs. DOACs exhibit pleiotropic actions on ECs, such as anti-inflammatory, anti-atherosclerotic, and anti-fibrotic effects, as well as preservation of endothelial integrity. These effects appear to be mediated through inhibition of the proteinase-activated receptor signaling pathway. Furthermore, we discuss the potential differences among the four drugs in this class. Further research is needed to fully understand the pleiotropic effects of DOACs on ECs, their underlying mechanisms, as well as the heterogeneity between various DOACs. Such studies can pave the way for identifying biomarkers that can help personalize pharmacotherapy with this valuable class of drugs.

ORal anticoaGulants in diAbetic and Nondiabetic patients with nOn-valvular atrial fibrillatioN (ORGANON)

BACKGROUND

Diabetes represents a pro-thrombotic condition.

OBJECTIVES

The primary objective was to evaluate the effects of Vitamin K Antagonist (VKA) compared to direct oral anticoagulants (DOACs) in diabetic and nondiabetic patients with non-valvular atrial fibrillation, newly diagnosed. The secondary objective was to evaluate the effects on the risk of bleeding.

METHODS

We enrolled 300 patients with newly diagnosed atrial fibrillation. One hundred and sixteen patients were taking warfarin, 31 acenocumarol, 22 dabigatran, 80 rivaroxaban, 34 apixaban, and 17 edoxaban. We evaluated: anthropometric parameters, glycated hemoglobin (HbA1c), fasting and post-prandial glucose (FPG, and PPG), lipid profile, Lp(a), small and dense low-density lipoprotein (SD-LDL), oxidized LDL (Ox-LDL), I-troponin (I-Tn), creatinine, transaminases, iron, red blood cells (RBC); hemoglobin (Hb), platelets (PLT), fibrinogen, D-dimer, anti-thrombin III, C-reactive protein (Hs-CRP), Metalloproteinases-2 (MMP-2), Metalloproteinases-9 (MMP-9), and incidence of bleeding.

RESULTS

We did not record any differences among nondiabetic patients between VKA and DOACs. However, when we considered diabetic patients, we found a slight, but significant improvement of triglycerides and SD-LDL. As regards incidence of bleeding, minor bleeding was more frequent in VKA diabetic group compared to DOACs diabetic group; furthermore, the incidence of major bleeding was higher with VKA in nondiabetic and diabetic group, compared to patients with DOACs. Among DOACs, we recorded a higher incidence of bleeding (minor and major) with dabigatran compared to rivaroxaban, apixaban and edoxaban in nondiabetic and diabetic patients.

CONCLUSION

DOACs seem to be metabolically favourable in diabetic patients. Regarding incidence of bleeding, DOACs with the exception of dabigatran, seem better than VKA in diabetic patients.

Pleiotropic effects of NOACs with focus on edoxaban: scientific findings and potential clinical implications

Non-vitamin K antagonist oral anticoagulants (NOACs) are well-established as inhibitors of factor Xa (FXa) and thrombin in the treatment and prevention of thrombosis. However, there is growing evidence that beneficial outcomes might be based on additional pleiotropic effects beyond anticoagulation. FXa and thrombin are also known to activate protease-activated receptors (PARs), which can mediate pro-inflammatory and pro-fibrotic effects. Since PAR‑1 and PAR‑2 play an important role in the development of atherosclerosis, the inhibition of this pathway represents an interesting potential target for preventing the progression of atherosclerosis and fibrosis. This review focuses on potential pleiotropic effects of FXa inhibition with edoxaban seen in a variety of studies in different in vitro and in vivo test systems. As common findings from these experiments, edoxaban was able to attenuate FXa- and thrombin-induced pro-inflammatory and pro-fibrotic effects and decrease pro-inflammatory cytokine expression. In some, but not all experiments edoxaban was also shown to decrease the levels of PAR‑1 and PAR‑2 expression. Further studies are required to clarify the clinical implications of the pleiotropic effects mediated by NOACs.

Emerging roles of protease-activated receptors in cardiometabolic disorders

Cardiometabolic disorders, including obesity-related insulin resistance and atherosclerosis, share sterile chronic inflammation as a major cause; however, the precise underlying mechanisms of chronic inflammation in cardiometabolic disorders are not fully understood. Accumulating evidence suggests that several coagulation proteases, including thrombin and activated factor X (FXa), play an important role not only in the coagulation cascade but also in the proinflammatory responses through protease-activated receptors (PARs) in many cell types. Four members of the PAR family have been cloned (PAR 1-4). For instance, thrombin activates PAR-1, PAR-3, and PAR-4. FXa activates both PAR-1 and PAR-2, while it has no effect on PAR-3 or PAR-4. Previous studies demonstrated that PAR-1 and PAR-2 activated by thrombin or FXa promote gene expression of inflammatory molecules mainly via the NF-κB and ERK1/2 pathways. In obese adipose tissue and atherosclerotic vascular tissue, various stresses increase the expression of tissue factor and procoagulant activity. Recent studies indicated that the activation of PARs in adipocytes and vascular cells by coagulation proteases promotes inflammation in these tissues, which leads to the development of cardiometabolic diseases. This review briefly summarizes the role of PARs and coagulation proteases in the pathogenesis of inflammatory diseases and describes recent findings (including ours) on the potential participation of this system in the development of cardiometabolic disorders. New insights into PARs may ensure a better understanding of cardiometabolic disorders and suggest new therapeutic options for these major health threats.

Integrating Mechanisms in Thrombotic Peripheral Arterial Disease

Peripheral arterial disease (PAD), a manifestation of systemic atherosclerosis, is underdiagnosed in the general population. Despite the extensive research performed to unravel its pathophysiology, inadequate knowledge exists, thus preventing the development of new treatments. This review aims to highlight the essential elements of atherosclerosis contributing to the pathophysiology of PAD. Furthermore, emphasis will be placed on the role of thrombo-inflammation, with particular focus on platelet and coagulation activation as well as cell-cell interactions. Additional insight will be then discussed to reveal the contribution of hypercoagulability to the development of vascular diseases such as PAD. Lastly, the current antithrombotic treatments will be discussed, and light will be shed on promising new targets aiming to aid the development of new treatments.

The impact of type 2 immunity and allergic diseases in atherosclerosis

Allergic diseases are allergen-induced immunological disorders characterized by the development of type 2 immunity and IgE responses. The prevalence of allergic diseases has been on the rise alike cardiovascular disease (CVD), which affects arteries of different organs such as the heart, the kidney and the brain. The underlying cause of CVD is often atherosclerosis, a disease distinguished by endothelial dysfunction, fibrofatty material accumulation in the intima of the artery wall, smooth muscle cell proliferation, and Th1 inflammation. The opposed T-cell identity of allergy and atherosclerosis implies an atheroprotective role for Th2 cells by counteracting Th1 responses. Yet, the clinical association between allergic disease and CVD argues against it. Within, we review different phases of allergic pathology, basic immunological mechanisms of atherosclerosis and the clinical association between allergic diseases (particularly asthma, atopic dermatitis, allergic rhinitis and food allergy) and CVD. Then, we discuss putative atherogenic mechanisms of type 2 immunity and allergic inflammation including acute allergic reactions (IgE, IgG1, mast cells, macrophages and allergic mediators such as vasoactive components, growth factors and those derived from the complement, contact and coagulation systems) and late phase inflammation (Th2 cells, eosinophils, type 2 innate-like lymphoid cells, alarmins, IL-4, IL-5, IL-9, IL-13 and IL-17).

Intracerebral hemorrhage and thrombin-induced alterations in cerebral microvessel matrix

Four phase III clinical trials of oral direct factor Xa or thrombin inhibitors demonstrated significantly lower intracranial hemorrhage compared to warfarin in patients with nonvalvular-atrial fibrillation. This is counter-intuitive to the principle that inhibiting thrombosis should increase hemorrhagic risk. We tested the novel hypothesis that anti-thrombin activity decreases the risk of intracerebral hemorrhage by directly inhibiting thrombin-mediated degradation of cerebral microvessel basal lamina matrix, responsible for preventing hemorrhage. Collagen IV, laminin, and perlecan each contain one or more copies of the unique α-thrombin cleavage site consensus sequence. In blinded controlled experiments, α-thrombin significantly degraded each matrix protein in vitro and in vivo in a concentration-dependent fashion. In vivo stereotaxic injection of α-thrombin significantly increased permeability, local IgG extravasation, and hemoglobin (Hgb) deposition together with microvessel matrix degradation in a mouse model. In all formats the direct anti-thrombin dabigatran completely inhibited matrix degradation by α-thrombin. Fourteen-day oral exposure to dabigatran etexilate-containing chow completely inhibited matrix degradation, the permeability to large molecules, and cerebral hemorrhage associated with α-thrombin. These experiments demonstrate that thrombin can degrade microvessel matrix, leading to hemorrhage, and that inhibition of microvessel matrix degradation by α-thrombin decreases cerebral hemorrhage. Implications for focal ischemia and other conditions are discussed.

Put out the fire: The pleiotropic anti-inflammatory action of non-vitamin K oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) should be the preferred anticoagulant strategy for preventing ischemic stroke in patients with atrial fibrillation (AF) at increased thromboembolic risk and for treating deep venous thromboembolism (DVT) in the general population. Beyond their inhibiting action on the activated factor X (FXa) or thrombin (FIIa), NOACs showed some pleiotropic anti-inflammatory effects. The present review aimed to describe the role of FXa and FIIa in the inflammation pathway and the potential anti-inflammatory effects of NOACs.

DOACs and Atherosclerotic Cardiovascular Disease Management: Can We Find the Right Balance Between Efficacy and Harm

PURPOSE OF REVIEW

The balance between efficacy and harm remains a challenge in the adoption of non-vitamin K antagonist direct oral anticoagulants (DOACs) for secondary atherosclerotic disease prevention. We provide a comprehensive review of the evidence for and against the addition of DOACs to the current management of atherosclerotic cardiovascular disease, including stable coronary artery disease (CAD), acute coronary syndrome (ACS), peripheral artery disease (PAD), and percutaneous coronary interventions (PCI).

RECENT FINDINGS

The DOAC class exerts pleiotropic effects on atherosclerotic progression through coagulation and inflammatory pathways. In ACS, low-dose DOAC provides no added efficacy in the setting of dual antiplatelet therapy; however, full-dose DOAC increases bleeding. Efficacy-safety profile favor use of low-dose rivaroxaban in select stable CAD or PAD patients. Atrial fibrillation patients undergoing PCI resort to dual therapy with DOAC due to prohibitory bleeding with triple anti-thrombotic therapy. Evidence favors DOAC use in CAD and PAD; however, careful individual considerations must be undertaken.

Lipidomics in Understanding Pathophysiology and Pharmacologic Effects in Inflammatory Diseases: Considerations for Drug Development

The lipidome has a broad range of biological and signaling functions, including serving as a structural scaffold for membranes and initiating and resolving inflammation. To investigate the biological activity of phospholipids and their bioactive metabolites, precise analytical techniques are necessary to identify specific lipids and quantify their levels. Simultaneous quantification of a set of lipids can be achieved using high sensitivity mass spectrometry (MS) techniques, whose technological advancements have significantly improved over the last decade. This has unlocked the power of metabolomics/lipidomics allowing the dynamic characterization of metabolic systems. Lipidomics is a subset of metabolomics for multianalyte identification and quantification of endogenous lipids and their metabolites. Lipidomics-based technology has the potential to drive novel biomarker discovery and therapeutic development programs; however, appropriate standards have not been established for the field. Standardization would improve lipidomic analyses and accelerate the development of innovative therapies. This review aims to summarize considerations for lipidomic study designs including instrumentation, sample stabilization, data validation, and data analysis. In addition, this review highlights how lipidomics can be applied to biomarker discovery and drug mechanism dissection in various inflammatory diseases including cardiovascular disease, neurodegeneration, lung disease, and autoimmune disease.

Recent advance in treatment of atherosclerosis: Key targets and plaque-positioned delivery strategies

Atherosclerosis, a chronic inflammatory disease of vascular wall, is a progressive pathophysiological process with lipids oxidation/depositing initiation and innate/adaptive immune responses. The coordination of multi systems covering oxidative stress, dysfunctional endothelium, diseased lipid uptake, cell apoptosis, thrombotic and pro-inflammatory responding as well as switched SMCs contributes to plaque growth. In this circumstance, inevitably, targeting these processes is considered to be effective for treating atherosclerosis. Arriving, retention and working of payload candidates mediated by targets in lesion direct ultimate therapeutic outcomes. Accumulating a series of scientific studies and clinical practice in the past decades, lesion homing delivery strategies including stent/balloon/nanoparticle-based transportation worked as the potent promotor to ensure a therapeutic effect. The objective of this review is to achieve a very brief summary about the effective therapeutic methods cooperating specifical targets and positioning-delivery strategies in atherosclerosis for better outcomes.

Dabigatran: its protective effect against endothelial cell damage by oxysterol

Recent data showed that dabigatran can reduce not only procoagulatory effects but also block proinflammatory stimuli by inhibiting the expression of cytokines and chemokines and reducing thrombin-induced endothelial permeability. The aim of our study was to assess the effect of dabigatran on the integrity and inflammatory properties of endothelial cells stimulated by 25-hydroxycholesterol (25-OHC, oxysterol). HUVECs (Human Umbilical Vein Endothelial Cells) were stimulated with 25-hydroxycholesterol 10 µg/ml, dabigatran 100 ng/ml or 500 ng/ml and 25-hydroxycholesterol + dabigatran (100 ng/ml, 500 ng/ml). HUVEC integrity and permeability was measured in the RTCA-DP xCELLigence system and by the paracellular flux system. The mRNA expression of ICAM-1, VEGF, IL-33, MCP-1 and TNF-α was analyzed by Real-time PCR. Cell apoptosis and viability was measured by flow cytometry. VEGF protein concentration was assessed in supernatants by ELISA. VE-cadherin expression in endothelial cells was evaluated by confocal microscopy. Pre-stimulation of HUVECs with 25-OHC decreased endothelial cell integrity (p < 0.001) and increased the expression of IL-33, ICAM-1, MCP-1, VEGF, TNF-α mRNA (p < 0.01) compared to unstimulated controls. Following stimulation of HUVECs with dabigatran 100 ng/ml or 500 ng/ml restored HUVEC integrity interrupted by 25-OHC (p < 0.001). In HUVECs pre-stimulated with oxysterol, dabigatran stimulation decreased mRNA expression of the proinflammatory cytokines IL-33 and TNF-α, chemokines MCP-1 ICAM-1 and VEGF (p < 0.01). Dabigatran 500 mg/ml+ 25-OHC increased the endothelial expression of VE-cadherin as compared to 25-OHC (p < 0.01). Our findings suggest that dabigatran stabilizes the endothelial barrier and inhibits the inflammation caused by oxysterol.

Towards Personalized Therapy of Aortic Stenosis

Calcific aortic stenosis (CAS) is the most common cause of acquired valvular heart disease in adults with no available pharmacological treatment to inhibit the disease progression to date. This review provides an up-to-date overview of current knowledge of molecular mechanisms underlying CAS pathobiology and the related treatment pathways. Particular attention is paid to current randomized trials investigating medical treatment of CAS, including strategies based on lipid-lowering and antihypertensive therapies, phosphate and calcium metabolism, and novel therapeutic targets such as valvular oxidative stress, coagulation proteins, matrix metalloproteinases, and accumulation of advanced glycation end products.

Vascular Protective Effects of New Oral Anticoagulants in Patients with Atrial Fibrillation

This study was designed to determine the efficacy of a new oral anticoagulant (NOAC) therapy for the prevention of endothelial dysfunction and atherosclerosis progression in patients with atrial fibrillation (AF). Sixty-five AF patients with a CHA2DS2-VASc score ≥2 without previous history of cardiovascular disease were registered and randomly assigned to either an NOAC group (dabigatran or rivaroxaban) or the warfarin group. Reactive hyperemia peripheral arterial tonometry (RH-PAT) measurements reflecting endothelial function were taken using Endo-PAT2000. Carotid intima–media thickness (IMT) was measured at baseline, 12 months, and 24 months, and several biomarkers were also analyzed. For the primary end point, the reactive hyperemia index (RHI) for the NOAC group was 1.5 ± 0.4 and that for the warfarin group was 1.6 ± 0.5. The left and right carotid IMT was 0.7 mm in the NOAC groups and 0.8 mm in the warfarin group. At 12 months, RHI was 1.6 ± 0.3 for the dabigatran group, 1.6 ± 0.5 for the rivaroxaban group, and 1.6 ± 0.3 for the warfarin group. The three groups did not differ statistically with respect to change in left and right carotid IMT at 12 and 24 months, respectively. The biomarkers for endothelial function and atherosclerosis were not significantly different. There was a trend of reduced P-selectin levels in the NOAC group compared to the warfarin group. In patients with AF, there were no significant differences in the prevention of endothelial dysfunction and atherosclerosis progression between the NOAC and warfarin groups.

New Possibilities in Quantitative Assessment of Albuminuria in Patients with Atrial Fibrillation and Chronic Kidney Disease

Aim. To evaluate the relationship between albumin to creatinine ratio (ACR) in a single and 24-hours urine spots and chronic kidney disease (CKD) progression pace in patients with atrial fibrillation, CKD and diabetes mellitus.

Material and methods. 60 patients with atrial fibrillation (AF) and CKD were enrolled, study duration was 15 months. The patients were divided into two groups depending on the presence of DM. Total number of ACR tests was 170, dynamics of CKD progression was estimated with CKD-EPI formula for first visit and 15th month’s follow-up.

Results. The median score of CHA2DS2VASс scale was 4 [3;5]. The risk of hemorrhagic complications in both groups was low (median score 1 [1;1]. There is a strong statistically significant correlation between ACR in a single and 24-hours urine spots (p<0.001). No significant changes in kidney function within 15 months were found (GFR 53 [46;59] ml/min/1.73 m2 vs 50.5 [45.63] ml/min/1.73 m2 for patients with diabetes mellitus [DM] [p=0.94] and GFR 52.5 [46.58] ml/min/1.73 m2 vs 50 [44.58] ml/min/1.73 m2 for patients without DM [p=0.711]). When comparing the renal function of patients with and without DM after 15 months statistically significant differences were also not found (p = 0.510).

Conclusion. In respect that assessment of single sample ACR is much more practical and reliable, this method might replace traditional 24-hours urine assessment in future. However, due to the small sample size and the presence of wide discrepancies in individual cases, which can be associated with preanalytical errors in urine collection, large randomized clinical trials are needed to confirm the obtained data.

Peri-interventional Triple Therapy With Dabigatran Improves Vasomotion and Promotes Endothelialization in Porcine Coronary Stenting Model

Objective: We evaluated the short and long-term effect of peri-interventional dabigatran therapy on vasomotion, endothelialization, and neointimal formation in a porcine coronary artery stenting model. Background: Stenting of coronary arteries induces local inflammation, impairs vasomotion and delays endothelialization. Methods: Twenty-eight animals underwent percutaneous coronary intervention (PCI) with drug eluting stents. Sixteen pigs started dabigatran therapy 4 days prior to PCI and continued for 4 days post-stenting, while 12 animals served as controls. Post-stenting dual antiplatelet therapy (75 mg clopidogrel and 100 mg aspirin) was continued in both groups until termination. Immediately post-stenting and at day 3 optical coherence tomography (OCT) was performed in all animals, followed by euthanasia of 8 dabigatran and 4 control animals. The remaining pigs (8 of each group) were followed up for 1 month, with control angiography and OCT. Tissue burden (degree of peri-strut structure-thrombus and/or fibrin) was evaluated. After euthanasia coronary arteries were harvested for in-vitro myometry and histology. Results: Thrombin generation was lower (p < 0.001) and tissue burden (0.83 ± 0.98 vs. 3.0 ± 2.45; p = 0.031) was significantly decreased in dabigatran treated animals. After 3 days post-PCI endothelium-dependent vasodilation was significantly improved (77 ± 40% vs. 41 ± 31%, p = 0.02) in dabigatran animals. Neither quantitative angiography nor histomorphometry showed differences between the groups. Endothelialization was faster in the dabigatran group as compared with controls (p = 0.045). Conclusion: Short-term peri-interventional triple therapy with dabigatran, aspirin, and clopidogrel led to an enhanced endothelium dependent vasodilation and faster endothelialization. However, neointimal formation 1-month after stent implantation was comparable between groups.

Aortic valvular stenosis: Novel therapeutic strategies

BACKGROUND

Aortic stenosis (AS) prevalence is estimated to reach 4.5 million cases worldwide by the year 2030. AS is a progressive disease without a pharmacological treatment. In the current review, we aimed to investigate novel therapeutic approaches for non-surgical AS treatment, at least in patients with mild-to-moderate AS.

MATERIALS AND METHODS

The most recent and relevant papers concerned with novel molecular pathways that have potential as therapeutic targets in AS were selected from searches of PubMed and Web of Science up to February 2021.

RESULTS

Growing evidence indicates that therapies using proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, simvastatin/ezetimibe combination, cholesteryl ester transfer protein inhibitors or antisense oligonucleotides targeting apolipoprotein(a) reduce the risk of AS progression. It has been shown that enhanced valvular lipid oxidation may drive AS development by leading to the activation of valvular interstitial cells (VICs), the most abundant valvular cells having a major contribution to valve calcification. Since VICs are able to release pro-inflammatory cytokines, clotting factors and proteins involved in calcification, strategies targeting these cell activations seem promising as therapeutic interventions. Recently, non-vitamin K antagonist oral anticoagulants (NOACs) have been shown to inhibit activation of VICs.

CONCLUSION

Several novel molecular pathways of AS development have been identified over the past few years. Therapies using PCSK9 inhibitors, simvastatin/ezetimibe combination, lipoprotein(a)-lowering therapy are highly promising candidates as therapeutics in the prevention of mild AS progression, while preclinical studies show that NOACs may inhibit valvular inflammation and coagulation activation and slower the rate of AS progression.

Off-target effects of oral anticoagulants - vascular effects of vitamin K antagonist and non-vitamin K antagonist oral anticoagulant dabigatran etexilate

INTRODUCTION

Vitamin K antagonists (VKA) and non-vitamin K oral antagonist anticoagulants (NOAC) are used in the clinic to reduce risk of thrombosis. However, they also exhibit vascular off-target effects. The aim of this study is to compare VKA and NOAC on atherosclerosis progression and calcification in an experimental setup.

MATERIAL AND METHODS

Female Apoe-/- mice (age 12 weeks) were fed Western-type diet as control or supplemented with dabigatran etexilate or warfarin for 6 or 18 weeks. Vascular calcification was measured in whole aortic arches using µCT and [18 F]-NaF. Atherosclerotic burden was assessed by (immuno)histochemistry. Additionally, in vitro effects of warfarin, thrombin, and dabigatran on primary vascular smooth muscle cells (VSMC) were assessed.

RESULTS

Short-term treatment with warfarin promoted formation of atherosclerotic lesions with a pro-inflammatory phenotype, and more rapid plaque progression compared with control and dabigatran. In contrast, dabigatran significantly reduced plaque progression compared with control. Long-term warfarin treatment significantly increased both presence and activity of plaque calcification compared with control and dabigatran. Calcification induced by warfarin treatment was accompanied by increased presence of uncarboxylated matrix Gla protein. In vitro, both warfarin and thrombin significantly increased VSMC oxidative stress and extracellular vesicle release, which was prevented by dabigatran.

CONCLUSION

Warfarin aggravates atherosclerotic disease activity, increasing plaque inflammation, active calcification, and plaque progression. Dabigatran lacks undesired vascular side effects and reveals beneficial effects on atherosclerosis progression and calcification. The choice of anticoagulation impacts atherosclerotic disease by differential off target effect. Future clinical studies should test whether this beneficial effect also applies to patients.

Pharmacological targeting of coagulation factor XI mitigates the development of experimental atherosclerosis in low-density lipoprotein receptor-deficient mice

BACKGROUND

Human coagulation factor (F) XI deficiency, a defect of the contact activation system, protects against venous thrombosis, stroke, and heart attack, whereas FXII, plasma prekallikrein, or kininogen deficiencies are asymptomatic. FXI deficiency, inhibition of FXI production, activated FXI (FXIa) inhibitors, and antibodies to FXI that interfere with FXI/FXII interactions reduce experimental thrombosis and inflammation. FXI inhibitors are antithrombotic in patients, and FXI and FXII deficiencies are atheroprotective in apolipoprotein E-deficient mice.

OBJECTIVES

Investigate the effects of pharmacological targeting of FXI in experimental models of atherogenesis and established atherosclerosis.

METHODS AND RESULTS

Low-density lipoprotein receptor-knockout (Ldlr-/- ) mice were administered high-fat diet (HFD) for 8 weeks; concomitantly, FXI was targeted with anti-FXI antibody (14E11) or FXI antisense oligonucleotide (ASO). 14E11 and FXI-ASO reduced atherosclerotic lesion area in proximal aortas when compared with controls, and 14E11 also reduced aortic sinus lesions. In an established disease model, in which therapy was given after atherosclerosis had developed, Ldlr-/- mice were fed HFD for 8 weeks and then administered 14E11 or FXI-ASO weekly until 16 weeks on HFD. In this established disease model, 14E11 and FXI-ASO reduced atherosclerotic lesion area in proximal aortas, but not in aortic sinus. In cultures of human endothelium, FXIa exposure disrupted VE-Cadherin expression and increased endothelial lipoprotein permeability. Strikingly, we found that 14E11 prevented the disruption of VE-Cadherin expression in aortic sinus lesions observed in the atherogenesis mouse model.

CONCLUSION

Pharmacological targeting of FXI reduced atherogenesis in Ldlr-/- mice. Interference with the contact activation system may safely reduce development or progression of atherosclerosis.

Non-Vitamin K Antagonist Oral Anticoagulants Provide Less Adverse Renal Outcomes Than Warfarin In Non-Valvular Atrial Fibrillation: A Systematic Review and MetaAnalysis

Background

Non‐vitamin K antagonist oral anticoagulants (NOACs) have better pharmacologic properties than warfarin and are recommended in preference to warfarin in most patients with non‐valvular atrial fibrillation. Besides lower bleeding complications, other advantages of NOACs over warfarin particularly renal outcomes remain inconclusive.

Methods and Results

Electronic searches were conducted through Medline, Scopus, Cochrane Library databases, and ClinicalTrial.gov. Randomized controlled trials and observational cohort studies reporting incidence rates and hazard ratio (HR) of renal outcomes (including acute kidney injury, worsening renal function, doubling serum creatinine, and end‐stage renal disease) were selected. The random‐effects model was used to calculate pooled incidence and HR with 95% CI. Eighteen studies were included. A total of 285 201 patients were enrolled, 118 863 patients with warfarin and 166 338 patients with NOACs. The NOACs group yielded lower incidence rates of all renal outcomes when compared with the warfarin group. Patients treated with NOACs showed significantly lower HR of risk of acute kidney injury (HR, 0.70, 95% CI, 0.64–0.76; P<0.001), worsening renal function (HR, 0.83; 95% CI, 0.73–0.95; P=0.006), doubling serum creatinine (HR, 0.58; 95% CI, 0.41–0.82; P=0.002), and end‐stage renal disease (HR, 0.82; 95% CI, 0.78–0.86; P<0.001).

Conclusions

In non‐valvular atrial fibrillation, patients treated with NOACs have a lower risk of both acute kidney injury and end‐stage renal disease when compared with warfarin.

Renal function and outcomes in atrial fibrillation patients after catheter ablation

BACKGROUND

Atrial fibrillation (AF) and renal failure coexist and interact. However, scarce data about association between renal function and clinical outcomes in patients undergoing catheter ablation for AF are available. We sought to evaluate long-term renal function and clinical outcomes after AF ablation.

METHODS

We enrolled 791 non-dialysis patients undergoing catheter ablation for AF, and evaluated the incidence of worsening renal function (WRF) after the procedure, defined as >30% decline in estimate glomerular filtration rate.

RESULTS

Mean follow-up duration was 5.1±2.5 years. Five hundreds and twenty-six patients (66.5%) were free from recurrent atrial arrhythmias without any antiarrhythmic drugs at the time of final follow-up. Cumulative incidence of WRF was 13.2% at 5-year after procedure, which was significantly higher in patients with recurrent AF compared to those without (21.6% versus 8.7%, P<0.001). In the multivariable analysis, recurrent AF was an independent risk factor for WRF (adjusted hazard ratio [HR] 1.89, 95% confidence interval 1.27-2.81, P = 0.002), along with congestive heart failure, diabetes, and eGFR <60 ml/min/1.73m2 at baseline. Patients with WRF had significantly higher 5-year incidences of all-cause death, cardiovascular death, heart failure hospitalization, ischemic stroke, and major bleeding compared to those without WRF. After adjustment of baseline differences in the multivariate Cox model, the excessive risks of WRF for all-cause death and heart failure hospitalization remained significant (adjusted HR 3.46, P = 0.002; adjusted HR 3.67, P<0.001).

CONCLUSIONS

In AF patients undergoing catheter ablation for AF, arrhythmia recurrence was associated with WRF during follow-up, which was a strong predictor of adverse clinical outcomes.

Thrombin, a Mediator of Coagulation, Inflammation, and Neurotoxicity at the Neurovascular Interface: Implications for Alzheimer's Disease

The societal burden of Alzheimer’s disease (AD) is staggering, with current estimates suggesting that 50 million people world-wide have AD. Identification of new therapeutic targets is a critical barrier to the development of disease-modifying therapies. A large body of data implicates vascular pathology and cardiovascular risk factors in the development of AD, indicating that there are likely shared pathological mediators. Inflammation plays a role in both cardiovascular disease and AD, and recent evidence has implicated elements of the coagulation system in the regulation of inflammation. In particular, the multifunctional serine protease thrombin has been found to act as a mediator of vascular dysfunction and inflammation in both the periphery and the central nervous system. In the periphery, thrombin contributes to the development of cardiovascular disease, including atherosclerosis and diabetes, by inducing endothelial dysfunction and related inflammation. In the brain, thrombin has been found to act on endothelial cells of the blood brain barrier, microglia, astrocytes, and neurons in a manner that promotes vascular dysfunction, inflammation, and neurodegeneration. Thrombin is elevated in the AD brain, and thrombin signaling has been linked to both tau and amyloid beta, pathological hallmarks of the disease. In AD mouse models, inhibiting thrombin preserves cognition and endothelial function and reduces neuroinflammation. Evidence linking atrial fibrillation with AD and dementia indicates that anticoagulant therapy may reduce the risk of dementia, with targeting thrombin shown to be particularly effective. It is time for “outside-the-box” thinking about how vascular risk factors, such as atherosclerosis and diabetes, as well as the coagulation and inflammatory pathways interact to promote increased AD risk. In this review, we present evidence that thrombin is a convergence point for AD risk factors and as such that thrombin-based therapeutics could target multiple points of AD pathology, including neurodegeneration, vascular activation, and neuroinflammation. The urgent need for disease-modifying drugs in AD demands new thinking about disease pathogenesis and an exploration of novel drug targets, we propose that thrombin inhibition is an innovative tactic in the therapeutic battle against this devastating disease.

Regression of Atherosclerosis in ApoE-/- Mice Via Modulation of Monocyte Recruitment and Phenotype, Induced by Weekly Dosing of a Novel "Cytotopic" Anti-Thrombin Without Prolonged Anticoagulation

Background Anticoagulants induce atherosclerosis regression in animal models but exploiting this clinically is limited by bleeding events. Here we test a novel thrombin inhibitor, PTL060, comprising hirulog covalently linked to a synthetic myristoyl electrostatic switch to tether to cell membranes. Methods and Results ApoE-/- mice were fed chow or high-fat diets, before transplantation of congenic aortic segments or injection of PTL060, parental hirulog, control saline, or labeled CD11b positive cells. Aortic transplants from transgenic mice expressing anticoagulants on endothelium did not develop atherosclerosis. A single intravenous injection of PTL060, but not hirulog inhibited atheroma development by >50% compared with controls when assessed 4 weeks later. Mice had prolonged bleeding times for only one seventh of the time that PTL060 was biologically active. Repeated weekly injections of PTL060 but not hirulog caused regression of atheroma. We dissected 2 contributory mechanisms. First, the majority of CCR2+ (C-C chemokine receptor type 2+) monocytes recruited into plaques expressed CCR7 (C-C chemokine receptor type 7), ABCA1 (ATP-binding cassette transporter - 1), and interleukin-10 in PTL060 mice, a phenotype seen in <20% of CCR2+ recruits in controls. Second, after several doses, there was a significant reduction in monocyte recruits, the majority of which were CCR2-negative with a similar regression-associated phenotype. Regression equivalent to that induced by intravenous PTL060 was induced by adoptive transfer of CD11b+ cells pre-coated with PTL060. Conclusions Covalent linkage of a myristoyl electrostatic switch onto hirulog in PTL060 uncouples the pharmacodynamic effects on hemostasis and atherosclerosis, such that plaque regression, mediated predominantly via effects on monocytes, is accompanied by only transient anticoagulation.

Tissue factor in atherosclerosis and atherothrombosis

Atherosclerosis is a chronic inflammatory disease that is characterized by the formation of lipid rich plaques in the wall of medium to large sized arteries. Atherothrombosis represents the terminal manifestation of this pathology in which atherosclerotic plaque rupture or erosion triggers the formation of occlusive thrombi. Occlusion of arteries and resultant tissue ischemia in the heart and brain causes myocardial infarction and stroke, respectively. Tissue factor (TF) is the receptor for the coagulation protease factor VIIa, and formation of the TF:factor VIIa complex triggers blood coagulation. TF is expressed at high levels in atherosclerotic plaques by both macrophage-derived foam cells and vascular smooth muscle cells, as well as extracellular vesicles derived from these cells. Importantly, TF mediated activation of coagulation is critically important for arterial thrombosis in the setting of atherosclerotic disease. The major endogenous inhibitor of the TF:factor VIIa complex is TF pathway inhibitor 1 (TFPI-1), which is also present in atherosclerotic plaques. In mouse models, increased or decreased expression of TFPI-1 has been found to alter atherosclerosis. This review highlights the contribution of TF-dependent activation of coagulation to atherthrombotic disease.

Switch to direct anticoagulants and improved endothelial function in patients with chronic heart failure and atrial fibrillation

BACKGROUND

Chronic heart failure (CHF) is characterized by higher rates of atrial fibrillation (AF) and endothelial dysfunction (ED). First line anticoagulant therapy in AF is represented by direct oral anticoagulants (DOACs); several patients, however, are still treated with vitamin-K inhibitors. The use of DOACs is associated in previous studies with an improved vascular function. We therefore sought to evaluate possible changes in endothelial function assessed by flow-mediated dilation (FMD) in patients with CHF and AF shifting from warfarin to DOACs.

METHODS

Forty-three consecutive outpatients were enrolled in the study. FMD was assessed at baseline and after 4 months. Patients were compared according to AC therapy.

RESULTS

After the first measurement of FMD, 18 patients "switched" to DOACs because of poor compliance to warfarin therapy or time in therapeutic range, 19 patients continued to use DOACs, 6 warfarin. "Switched" patients to DOACs therapy showed an improved FMD (19.0 ± 6.6% vs 3.8 ± 1.3%, p < 0.0001); C-reactive protein (CRP) levels decreased in "switched" patients from 1.4 ± 0.5 to 1.0 ± 0.7 mg/dl (p < 0.05). FMD and CRP changes were not significant in patients who did not changed anticoagulant therapy. In switched patients, changes in CRP levels were proportional to FMD changes (r = -0.50, p < 0.05). Shifting from warfarin to DOACs was significantly correlated to improved FMD levels even at multivariable analysis (p < 0.05).

CONCLUSIONS

Switch from warfarin to DOACs in patents with CHF and AF was associated in an observational non randomized study with an improved endothelial function. Changes in FMD values were related to changes in CRP levels.

NLRP3 Inflammasome Signaling as a Link Between HIV-1 Infection and Atherosclerotic Cardiovascular Disease

36.9 million people worldwide are living with HIV-1. The disease remains incurable and HIV-infected patients have increased risk of atherosclerosis. Inflammation is a key driver of atherosclerosis, but no targeted molecular therapies have been developed to reduce cardiovascular risk in people with HIV-1 (PWH). While the mechanism is unknown, there are several important inflammatory signaling events that are implicated in the development of chronic inflammation in PWH and in the inflammatory changes that lead to atherosclerosis. Here we describe the pro-inflammatory state of HIV-1 infection that leads to increased risk of cardiovascular disease, the role of the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in HIV-1 infection, the role of the NLRP3 inflammasome in cardiovascular disease (CVD), and outline a model whereby HIV-1 infection can lead to atherosclerotic disease through NLRP3 inflammasome activation. Our discussion highlights the literature supporting HIV-1 infection as a stimulator of the NLRP3 inflammasome as a driver of atherosclerosis.

Effects of rivaroxaban and dabigatran on local expression of coagulation and inflammatory factors within human aortic stenotic valves

BACKGROUND

Treatment with non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran (a direct thrombin inhibitor) or rivaroxaban (a direct inhibitor of factor [F] Xa) attenuates atherosclerotic plaque progression in hypercholesterolemic mice.

PURPOSE

To evaluate the effect of NOACs application on the expression of coagulation proteins in loco within stenotic aortic valves and in valve interstitial cells (VICs) from patients with severe aortic stenosis (AS).

METHODS

Primary cultures of VICs obtained from 90 patients undergoing aortic valve replacement were stimulated with TNF-α (50 ng/mL) and pre-treated with rivaroxaban (1 and 10 ng/mL) or dabigatran (25 and 250 ng/mL). The expression of coagulation proteins was analyzed by immunofluorescence. Cytokine levels were measured by ELISA.

RESULTS

FX, FXa, FVII, thrombin and PAR1/2 were present in loco within human aortic stenotic valves. Cultured VICs exhibited constant expression of FX, TF, PAR1/2. Exposure of VICs to TNF-α caused the upregulated expression of TF, PAR1/2 and induced expression of thrombin, FVII and FXa. FX was expressed by 80% of VICs, regardless of stimulation. Cultured VICs were able to synthesize metalloproteinases 1-3, IL-6, IL-32, IL-34, osteopontin and osteocalcin, the levels of which increased under TNF-α stimulation. NOACs added to culture inhibited coagulation factor and PAR1/2 expression. Moreover, NOACs down-regulated VIC-derived proteins responsible for valve calcification and extracellular matrix remodeling.

CONCLUSIONS

NOACs at therapeutic concentrations may inhibit the effects of FXa and thrombin at in vitro level. It might be speculated that long-term treatment with rivaroxaban or dabigatran could attenuate the progression of AS in humans.

Platelet activation and prothrombotic mediators at the nexus of inflammation and atherosclerosis: Potential role of antiplatelet agents

Platelets are central to inflammation-related manifestations of cardiovascular diseases (CVD) such as atherosclerosis. Platelet-activating factor (PAF), thrombin, thromboxane A₂ (TxA₂), and adenosine diphosphate (ADP) are some of the key agonists of platelet activation that are at the intersection between a plethora of inflammatory pathways that modulate pro-inflammatory and coagulation processes. The aim of this article is to review the role of platelets and the relationship between their structure, function, and the interactions of their constituents in systemic inflammation and atherosclerosis. Antiplatelet therapies are discussed with a view to primary prevention of CVD by the clinical reduction of platelet reactivity and inflammation. Current antiplatelet therapies are effective in reducing cardiovascular risk but increase bleeding risk. Novel therapeutic antiplatelet approaches beyond current pharmacological modalities that do not increase the risk of bleeding require further investigation. There is potential for specifically designed nutraceuticals that may become safer alternatives to pharmacological antiplatelet agents for the primary prevention of CVD but there is serious concern over their efficacy and regulation, which requires considerably more research.

Systematic DOACs oral anticoagulation in patients with atrial fibrillation and chronic kidney disease: the nephrologist's perspective

Atrial fibrillation (AF) is highly prevalent among patients with chronic kidney disease (CKD), and also associated with unfavorable outcome. Anticoagulant therapy is the mainstep of management in such patients, aimed at reducing the high risk of systemic thromboembolism and especially of ischemic stroke, which is reportedly associated with increased mortality in CKD patients. Even though new direct oral anticoagulant agents (DOACs) proved to be effective in patients with non valvular chronic AF, and are therefore recommended by recent guidelines for their treatment, warfarin is currently used in more than one-half of subjects needing oral anticoagulation, and only 30% of them are converted from a vitamin K antagonist- to a DOAC-based regimen. The main reason for not prescribing DOACs is often a reduction in renal function, even if mild. Aim of this review was therefore to evaluate the impact of DOAC therapy in the setting of CKD, from a nephrological perspective, by comparing available evidence on the role of DOACs in patients with CKD and AF with that emerging from traditional warfarin-based therapy. Both the pathogenesis of AF in CKD, and available findings of renal, cardiovascular and bone effects of DOACs in CKD are discussed, leading to the conclusion that DOAC therapy should be considered as the first line therapy for non valvular AF in patients with mild and moderate reduction of renal function, and could also be adopted for patients with severe CKD not on hemodialysis treatment, whereas there is insufficient evidence for ESRD patients on dialysis.

Effects of edoxaban and warfarin on vascular remodeling: Atherosclerotic plaque progression and collateral artery growth

BACKGROUND AND PURPOSE

Oral anticoagulation prevents thromboembolism in atrial fibrillation. Factor Xa inhibitors, like edoxaban, are known to reduce inflammation and proliferation of smooth muscle cells, while vitamin K antagonism can cause vascular calcific damage. The influence of edoxaban compared to warfarin on vascular remodeling, atherosclerosis and arteriogenesis is unknown.

EXPERIMENTAL APPROACH

Apolipoprotein E knockout (ApoE ^-/-) mice were fed cholesterol-rich diet alone (control, co), with warfarin+vitamin K1 (warf) or with edoxaban (Edo) for 8 weeks. After 6 weeks, femoral artery ligation was performed.

KEY RESULTS

There was no difference in hind-limb perfusion restoration between the three groups after 14 days (Co 0.36 ± 0.05 vs. Warf 0.39 ± 0.09 (p = .39), Co vs. Edo 0.51 ± 0.06 (p = .089), Warf vs. Edo (p = .83)) after ligation. Immuno-histologically, there was no difference in smooth muscle cell count in both hindlimbs between the three groups or in the amount of perivascular macrophages in collateral-bearing hindlimb tissue. Edoxaban showed the lowest amount of plaque tissue in the aortic sinus tissue (Co 74 ± 11% vs. Edo 62 ± 12% (p = .024), Co vs. Warf 69 ± 14% (p = .30), Edo vs. Warf (p = .14)) as well as the least amount of fibrosis (Co 3.1 ± 0.9% vs. Edo 1.7 ± 0.6% (p = .027), Co vs. Warf 4.1 ± 0.7% (p = .081), Edo vs. Warf (p < .001)). No difference in mRNA content of inflammatory cytokines in muscle tissue or spleen was detected between the three groups.

CONCLUSION AND IMPLICATIONS

These data suggest that treatment with edoxaban unlike warfarin prevents vascular maladaptive remodeling, which may be clinically important.

Persistent Systemic Inflammation Is Associated With Bleeding Risk in Atrial Fibrillation Patients

BACKGROUND

This study investigated the impact of systemic inflammation on bleeding risk in non-valvular atrial fibrillation (NVAF) patients treated with direct oral anticoagulants (DOAC).Methods and Results:We conducted a single-center prospective registry of 2,216 NVAF patients treated with DOAC: the DIRECT registry (UMIN000033283). High-sensitivity C-reactive protein (hsCRP) was measured ≤3 months before (pre-DOAC hsCRP) and 6±3 months after initiation of DOAC (post-DOAC hsCRP). Multivariate logistic regression model was used to assess the influence of systemic inflammation and conventional bleeding risk factors on major bleeding according to International Society on Thrombosis and Haemostasis criteria. Based on the findings, we created a new bleeding risk assessment score: the ORBIT-i score, which included post-DOAC hsCRP >0.100 mg/dL and all components of the ORBIT score. A total of 1,848 patients had both pre- and post-DOAC hsCRP data (follow-up duration, 460±388 days). Post-DOAC hsCRP was associated with major bleeding (OR, 2.770; 95% CI: 1.687-4.548, P<0.001). Patients with post-DOAC hsCRP >0.100 mg/dL more frequently had major bleeding than those without (log-rank test, P<0.001). ORBIT-i score had the highest C-index of 0.711 (95% CI, 0.654-0.769) compared with the ORBIT and HAS-BLED scores.

CONCLUSIONS

Persistent systemic inflammation was associated with major bleeding risk. ORBIT-i score had a higher discriminative performance compared with the conventional bleeding risk scores.

Antithrombotic Therapy: Prevention and Treatment of Atherosclerosis and Atherothrombosis

Atherosclerosis is a multifactorial vascular disease that develops in the course of a lifetime. Numerous risk factors for atherosclerosis have been identified, mostly inflicting pro-inflammatory effects. Vessel injury, such as occurring during erosion or rupture of atherosclerotic lesions triggers blood coagulation, in attempt to maintain hemostasis (protect against bleeding). However, thrombo-inflammatory mechanisms may drive blood coagulation such that thrombosis develops, the key process underlying myocardial infarction and ischemic stroke (not due to embolization from the heart). In the blood coagulation system, platelets and coagulation proteins are both essential elements. Hyperreactivity of blood coagulation aggravates atherosclerosis in preclinical models. Pharmacologic inhibition of blood coagulation, either with platelet inhibitors, or better documented with anticoagulants, or both, limits the risk of thrombosis and may potentially reverse atherosclerosis burden, although the latter evidence is still based on animal experimentation.Patients at risk of atherothrombotic complications should receive a single antiplatelet agent (acetylsalicylic acid, ASA, or clopidogrel); those who survived an atherothrombotic event will be prescribed temporary dual antiplatelet therapy (ASA plus a P2Y12 inhibitor) in case of myocardial infarction (6-12 months), or stroke (<6 weeks), followed by a single antiplatelet agent indefinitely. High risk for thrombosis patients (such as those with peripheral artery disease) benefit from a combination of an anticoagulant and ASA. The price of gained efficacy is always increased risk of (major) bleeding; while tailoring therapy to individual needs may limit the risks to some extent, new generations of agents that target less critical elements of hemostasis and coagulation mechanisms are needed to maintain efficacy while reducing bleeding risks.

Thrombin inhibition by dabigatran attenuates endothelial dysfunction in diabetic mice

Diabetic patients have coagulation abnormalities, in which thrombin plays a key role. Whereas accumulating evidence suggests that it also contributes to the development of vascular dysfunction through the activation of protease-activated receptors (PARs). Here we investigated whether the blockade of thrombin attenuates endothelial dysfunction in diabetic mice. Induction of diabetes by streptozotocin (STZ) increased the expression of PAR1, PAR3, and PAR4 in the aorta. STZ-induced diabetic mice showed impairment of endothelial function, while the administration of dabigatran etexilate, a direct thrombin inhibitor, significantly attenuated endothelial dysfunction in diabetic mice with no alteration of metabolic parameters including blood glucose level. Dabigatran did not affect endothelium-independent vasodilation. Dabigatran decreased the expression of inflammatory molecules (e.g., MCP-1 and ICAM-1) in the aorta of diabetic mice. Thrombin increased the expression of these inflammatory molecules and the phosphorylation of IκBα, and decreased the phosphorylation of eNOS^Ser1177 in human umbilical endothelial cells (HUVEC). Thrombin significantly impaired the endothelium-dependent vascular response of aortic rings obtained from wild-type mice. Inhibition of NF-κB attenuated thrombin-induced inflammatory molecule expression in HUVEC and ameliorated thrombin-induced endothelial dysfunction in aortic rings. Dabigatran attenuated the development of diabetes-induced endothelial dysfunction. Thrombin signaling may serve as a potential therapeutic target in diabetic condition.

Targeting Coagulation Factor Xa Promotes Regression of Advanced Atherosclerosis in Apolipoprotein-E Deficient Mice

Atherosclerosis is a progressive inflammatory vascular disorder, complicated by plaque rupture and subsequently atherothrombosis. In vitro studies indicate that key clotting proteases, such as factor Xa (FXa), can promote atherosclerosis, presumably mediated through protease activated receptors (PARs). Although experimental studies showed reduced onset of atherosclerosis upon FXa inhibition, the effect on pre-existing plaques has never been studied. Therefore, we investigated effects of FXa inhibition by rivaroxaban on both newly-formed and pre-existing atherosclerotic plaques in apolipoprotein-e deficient (ApoE^-/-) mice. Female ApoE^-/- mice (age: 8-9 weeks, n = 10/group) received western type diet (WTD) or WTD supplemented with rivaroxaban (1.2 mg/g) for 14 weeks. In a second arm, mice received a WTD for 14 weeks, followed by continuation with either WTD or WTD supplemented with rivaroxaban (1.2 mg/g) for 6 weeks (total 20 weeks). Atherosclerotic burden in aortic arch was assessed by haematoxilin & eosin immunohistochemistry (IHC); plaque vulnerability was examined by IHC against macrophages, collagen, vascular smooth muscle cells (VSMC) and matrix metalloproteinases (MMPs). In addition, PAR1 and -2 expressions and their main activators thrombin and FXa in the plaque were determined in the plaque. Administration of rivaroxaban at human therapeutic concentrations reduced the onset of atherosclerosis (-46%, p < 0.05), and promoted a regression of pre-existing plaques in the carotids (-24%, p < 0.001). In addition, the vulnerability of pre-existing plaques was reduced by FXa inhibition as reflected by reduced macrophages (-39.03%, p < 0.05), enhanced collagen deposition (+38.47%, p < 0.05) and diminished necrotic core (-31.39%, p < 0.05). These findings were accompanied with elevated vascular smooth muscle cells and reduced MMPs. Furthermore, expression of PARs and their activators, thrombin and FXa was diminished after rivaroxaban treatment. Pharmacological inhibition of FXa promotes regression of advanced atherosclerotic plaques and enhances plaque stability. These data suggest that inhibition of FXa may be beneficial in prevention and regression of atherosclerosis, possibly mediated through reduced activation of PARs.

Vascular protease-activated receptor 4 upregulation, increased platelet aggregation, and coronary lipid deposits induced by long-term dabigatran administration - results from a diabetes animal model

Essentials The impact of long-term thrombin inhibition outside the coagulation cascade is far from clear. We aimed to assess the impact of dabigatran etexilate (DE) in diabetic and control rats. In diabetic rats, DE increased platelet aggregation and lead to coronary lipid deposits. Long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk. SUMMARY: Background Besides its role in the coagulation cascade, thrombin contributes to platelet aggregation and to a plethora of non-hemostatic functions. Objectives To assess the impact of long-term thrombin inhibition with dabigatran etexilate (DE) on platelet aggregation and on extrahemostatic thrombin-related functions in diabetic and control rats. Methods Markers of inflammation, endothelial dysfunction, oxidative stress, angiogenesis and cell adhesion molecules were quantified in control rats (Control; n = 6), DE-treated control rats (Control-Dabi; n = 8), diabetic rats (Diabetes; n = 5), and DE-treated diabetic rats (Diabetes-Dabi; n = 8). Agonist-induced platelet aggregation, aortic and coronary lipid deposits and aortic protease-activated receptor 4 (PAR4) expression were also assessed. Results Control-Dabi rats showed significantly higher high-sensitivity C-reactive protein, von Willebrand factor (VWF), vascular endothelial growth factor (VEGF) and fibronectin levels, and significantly lower PAR4 agonist-induced aggregation, than Control rats. Control-Dabi rats also showed mild aortic lipid deposits, whereas no such changes were observed in Control rats. Diabetes-Dabi rats showed significantly higher VWF, VEGF and fibronectin levels than Diabetes rats, and similar PAR4 agonist-induced aggregation as Diabetes rats, and significantly higher ADP-induced aggregation than Diabetes rats. Coronary lipid deposits were observed in 75% of Diabetes-Dabi rats and in none of the Diabetes rats. PAR4 expression was 20.4% higher in Control-Dabi rats and 27.4% higher in Diabetes-Dabi rats than in their non-treated peers. Conclusions This study indicates that long-term thrombin inhibition increases vascular PAR4 expression, promotes atherosclerosis-related mechanisms, and, in diabetic rats, increases platelet aggregation and favors the occurrence of coronary lipid deposits. These experimental data suggest that long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk, particularly in the presence of diabetes.

Direct oral anticoagulants and vitamin K antagonists are linked to differential profiles of cardiac function and lipid metabolism

BACKGROUND

Experimental data indicate that direct acting oral anticoagulants (DOAC) and vitamin K antagonists (VKA) may exert differential effects on cardiovascular disease.

METHODS

Data from the prospective, observational, single-center MyoVasc Study were used to examine associations of DOAC as compared to VKA with subclinical markers of cardiovascular disease, cardiac function, and humoral biomarkers in heart failure (HF).

RESULTS

Multivariable analysis adjusted for age, sex, traditional cardiovascular risk factors, comorbidities, and medications with correction for multiple testing demonstrated that DOAC therapy was among all investigated parameters an independent significant predictor of better diastolic function (E/E': β - 0.24 [- 0.36/- 0.12]; P < 0.0001) and higher levels of ApoA1 (β + 0.11 g/L [0.036/0.18]; P = 0.0038) compared to VKA therapy. In propensity score-weighted analyses, the most pronounced differences between DOAC and VKA-based therapy were also observed for E/E' (∆ - 2.36) and ApoA1 (∆ + 0.06 g/L). Sensitivity analyses in more homogeneous subsamples of (i) individuals with AF and (ii) individuals with asymptomatic HF confirmed the consistency and robustness of these findings. In the comparison of factor IIa and Xa-directed oral anticoagulation, no differences were observed regarding cardiac function (E/E' ratio: β_{IIa inhibitor} - 0.22 [- 0.36/- 0.08] vs. β_{Xa inhibitor} - 0.24 [- 0.37/- 0.11]) and lipid metabolism (ApoA1: β_{IIa inhibitor} 0.10 [0.01/0.18] vs. β_{Xa inhibitor} 0.12 [0.04/0.20]) compared to VKA therapy.

CONCLUSION

This study provides the first evidence for differential, non-conventional associations of oral anticoagulants on cardiac function and lipid metabolism in humans. The potentially beneficial effect of DOACs in the highly vulnerable population of HF individuals needs to be further elucidated and may have implications for individually tailored anticoagulation therapy.

Roles of Coagulation Proteases and PARs (Protease-Activated Receptors) in Mouse Models of Inflammatory Diseases

Activation of the blood coagulation cascade leads to fibrin deposition and platelet activation that are required for hemostasis. However, aberrant activation of coagulation can lead to thrombosis. Thrombi can cause tissue ischemia, and fibrin degradation products and activated platelets can enhance inflammation. In addition, coagulation proteases activate cells by cleavage of PARs (protease-activated receptors), including PAR1 and PAR2. Direct oral anticoagulants have recently been developed to specifically inhibit the coagulation proteases FXa (factor Xa) and thrombin. Administration of these inhibitors to wild-type mice can be used to determine the roles of FXa and thrombin in different inflammatory diseases. These results can be compared with the phenotypes of mice with deficiencies of either Par1 (F2r) or Par2 (F2rl1). However, inhibition of coagulation proteases will have effects beyond reducing PAR signaling, and a deficiency of PARs will abolish signaling from all proteases that activate these receptors. We will summarize studies that examine the roles of coagulation proteases, particularly FXa and thrombin, and PARs in different mouse models of inflammatory disease. Targeting FXa and thrombin or PARs may reduce inflammatory diseases in humans.

Comparison of anti-inflammatory effects of rivaroxaban vs. dabigatran in patients with non-valvular atrial fibrillation (RIVAL-AF study): multicenter randomized study

Some experimental studies have shown that direct oral anticoagulants (DOACs) have anti-inflammatory effects. However, the interval changes in inflammatory markers in patients with non-valvular atrial fibrillation (AF) who receive DOACs remain unknown. Between July 2013 and April 2014, a total of 187 AF patients randomly assigned to receive rivaroxaban (n = 91) or dabigatran (n = 96) were assessed for eligibility. The levels of the following inflammatory markers were serially evaluated: high-sensitivity C-reactive protein, pentraxin-3, interleukin (IL)-1β, IL-6, IL-18, tumor necrosis factor-α, monocyte chemotactic protein-1, growth and differentiation factor-15, and soluble thrombomodulin (sTM). The aim in this study was to evaluate the anti-inflammatory effects of rivaroxaban and dabigatran in patients with AF, in addition to the impact of markers on bleeding events. Finally, 117 patients (rivaroxaban: n = 55, dabigatran: n = 62) were included in the analysis at 12 months. Although the interval changes in sTM levels tended to be greater in the dabigatran group [0.3 (0-0.7) vs. 0.5 (0-1.0) FU/ml, p = 0.061], there were no significant differences in the interval changes in any inflammatory marker between 2 groups. There were no significant differences in bleeding events between 2 groups. The interval changes in sTM levels were significantly greater in patients with bleeding compared with those without [0.8 (0.5-1.3) vs. 0.4 (- 0.1-0.8) FU/ml, p = 0.017]. There were no significant differences in the interval changes in any inflammatory marker between rivaroxaban and dabigatran treatments in patients with AF. The increased levels of sTM after DOACs treatment might be related to bleeding events.

Non-cardioembolic risk factors in atrial fibrillation-associated ischemic stroke

Introduction

Cardioembolic (CE) risks is usually considered as the main mechanism of ischemic stroke in non-valvular atrial fibrillation (NVAF) patients. However, a substantial number of ischemic strokes in NVAF patients are related to non-CE mechanisms. The aim of this study was to investigate the non-CE risk factors in ischemic stroke patients had NVAF.

Methods

We included 401 patients (65.6% male, 68.6 ± 9.6 years old) who had been hospitalized due to ischemic stroke and had a known or newly diagnosed NVAF. The CE (intracardiac thrombus, dense spontaneous echo contrast, or low left atrial appendage flow velocity) and non-CE (complex aortic plaque, significant carotid stenosis, or intracranial arterial stenosis) risk factors were investigated at the time of the index stroke.

Results

The number of CE and non-CE risk factors increased with increasing CHA₂DS₂-VASc scores (p for trends < 0.001). The presence of CE risk factors was independently associated with persistent atrial fibrillation (p < 0.001), body mass index (p = 0.003), heart failure (p = 0.003), and left atrial volume index (p < 0.001). In contrast, the presence of non-CE risk factors was independently associated with age (p < 0.001), hypertension (p = 0.049), diabetes (p = 0.030), and coronary artery calcium score (CACS; p < 0.001). CACS had the added value in predicting non-CE risk factors of ischemic stroke regardless of the CHA₂DS₂-VASc risk category (p < 0.001).

Conclusion

Non-CE risk factors in ischemic stroke patients with NVAF are associated with high CHA₂DS₂-VASc score and CACS. Atherosclerotic non-CE risk factors should be considered as potential mechanisms of stroke even in patients with AF-associated ischemic stroke.

Pleiotropic effects of the hemostatic system

Atherothrombosis is characterized by the inflammatory process of atherosclerosis combined with a hypercoagulable state leading to superimposed thrombus formation. In atherosclerotic plaques, cell signaling can occur via protease-activated receptors (PARs), four of which have been identified so far (PAR1-PAR4). Proteases that are able to activate PARs can be produced systemically, but also at the sites of lesions, and they include thrombin and activated factor X. After PAR activation, downstream signaling can lead to both proinflammatory effects and a hypercoagulable state. Which specific effect occurs depends on the type of protease and activated PAR, and the site of activation. Hypercoagulable effects are mainly exerted through PAR1 and PAR4, whereas proinflammatory responses are mostly seen after PAR1 and PAR2 activation. PAR signaling pathways contribute to atherothrombosis, suggesting that inhibition of these pathways possibly prevents cardiovascular events based on this pathophysiological mechanism. In this review, we highlight the pathways by which PAR activation leads to proinflammatory responses and a hypercoagulable state. Furthermore, we give an overview of potential pharmacological treatment targets that promote vascular protection.