Tomoya Hara

Rivaroxaban, a novel oral anticoagulant, attenuates atherosclerotic plaque progression and destabilization in ApoE-deficient mice

OBJECTIVE Activated factor X (FXa) plays a key role in the coagulation cascade, whereas accumulating evidence suggests that it also contributes to the pathophysiology of chronic inflammation on the vasculature. In this study, we assessed the hypothesis that rivaroxaban (Riv), a direct FXa inhibitor, inhibits atherogenesis by reducing macrophage activation. METHODS AND RESULTS Expression levels of PAR-1 and PAR-2, receptors for FXa, increased in the aorta of apolipoprotein E-deficient (ApoE(-/-)) mice compared with wild-type mice (P < 0.01, P < 0.05, respectively). Administration of Riv (5 mg/kg/day) for 20 weeks to 8-week-old ApoE(-/-) mice reduced atherosclerotic lesion progression in the aortic arch as determined by en-face Sudan IV staining compared with the non-treated group (P < 0.05) without alteration of plasma lipid levels and blood pressure. Histological analyses demonstrated that Riv significantly decreased lipid deposition, collagen loss, macrophage accumulation and matrix metallopeptidase-9 (MMP-9) expression in atherosclerotic plaques in the aortic root. Quantitative RT-PCR analyses using abdominal aorta revealed that Riv significantly reduced mRNA expression of inflammatory molecules, such as MMP-9, tumor necrosis factor-α (TNF-α). In vitro experiments using mouse peritoneal macrophages or murine macrophage cell line RAW264.7 demonstrated that FXa increased mRNA expression of inflammatory molecules (e.g., interleukin (IL)-1β and TNF-α), which was blocked in the presence of Riv. CONCLUSIONS Riv attenuates atherosclerotic plaque progression and destabilization in ApoE(-/-) mice, at least in part by inhibiting pro-inflammatory activation of macrophages. These results indicate that Riv may be particularly beneficial for the management of atherosclerotic diseases, in addition to its antithrombotic activity.

Effects of Docosahexaenoic Acid on the Endothelial Function in Patients with Coronary Artery Disease

AIM The consumption of n-3 polyunsaturated fatty acids (PUFA), including docosahexaenoic acid DHA), reduces the incidence of cardiovascular events, and reduced serum levels of n-3 PUFA may be associated with an increased risk of cardiovascular events. However, controversy remains regarding which components of PUFA are associated with the endothelial function in patients with coronary artery disease (CAD). We therefore examined the associations between the n-3 and n-6 PUFA levels and CAD. METHODS We retrospectively reviewed 160 consecutive Japanese patients with CAD whose endothelial function was measured according to the percent change in flow-mediated dilation (FMD) and the serum levels of n-3 PUFA, including eicosapentaenoic acid (EPA) and DHA, and n-6 PUFA, including arachidonic acid (AA) and dihomo-gamma-linolenic acid (DHLA). RESULTS A single regression analysis showed no relationships between the FMD and the serum levels of PUFA, including EPA, DHA, AA and DHLA. In contrast, a multiple regression analysis showed that the DHA level was a positive (＜ 0.01) and age was a negative (P ＜ 0.001) contributor to an increased FMD; however, sex, body mass index, systolic and diastolic blood pressure, current/past smoking and the levels of HbA1c, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, EPA, AA and DHLA did not significantly affect the outcome. CONCLUSIONS The serum level of DHA is associated with the endothelial function evaluated according to the FMD in patients with CAD, thus suggesting that a low serum level of DHA may be a predictive biomarker for endothelial dysfunction.

Serum concentration of eicosapentaenoic acid is associated with cognitive function in patients with coronary artery disease

BackgroundRecent studies have shown that intake of n-3 polyunsaturated fatty acids (PUFAs) is associated with reduced risk of cognitive impairment and coronary artery disease (CAD); however, it is currently unknown whether reduced serum n-3 PUFA is associated with cognitive impairment in patients with CAD.MethodsWe retrospectively evaluated cognitive function with the mini-mental state examination (MMSE), serum levels of PUFAs (including eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], dihomogammalinolenic acid [DGLA], and arachidonic acid [AA]), cardiovascular risk factors (hypertension, dyslipidemia, diabetes mellitus, cerebrovascular disease, and history of current/previous smoking), and parameters of cardiac function (left ventricular ejection fraction and brain natriuretic peptide levels) in 146 Japanese CAD patients. The associations between the MMSE scores and the other parameters were evaluated.ResultsPearson correlation analysis showed that EPA (R = 0.25, P <0.01), EPA/AA ratio (R = 0.22, P = 0.01), and left ventricular ejection fraction (R = 0.15, P = 0.04) were positively associated with MMSE score, and that age (R = −0.20, P <0.01) and brain natriuretic peptide levels (R = −0.28, P <0.01) were inversely associated with MMSE score. Multiple regression analysis showed that age (P <0.05) was negatively associated with MMSE score, while EPA (P <0.01) and EPA/AA ratio (P <0.05) were positively associated with MMSE score; however, sex; body mass index; left ventricular ejection fraction; levels of DHA, AA, and DGLA; DHA/AA ratio; brain natriuretic peptide; and presence of hypertension, dyslipidemia, diabetes mellitus, cerebrovascular disease, and history of current/previous smoking were statistically excluded.ConclusionsSerum EPA concentration is associated with cognitive function in patients with CAD, suggesting that a low serum EPA level is a risk factor for cognitive impairment independent of cardiac function, including left ventricular ejection fraction. This correlation potentially lends further support to a role of dietary n-3 PUFAs in preventing the cognitive decline in CAD patients.

A case of successful use of microsnare to hold and pull the retrograde guidewire for the intervention to peripheral chronic total occlusion

A basket-shaped microsnare has various uses such as the pull through technique during coronary intervention to chronic total occlusion (CTO). A 79-year-old man underwent angioplasty for the femoral artery occlusion. We performed a controlled antegrade and retrograde tracking (CART) with dilatation of a balloon on the antegrade guidewire. The retrograde guidewire partly ran in the true lumen but could not pass through the CTO lesion because of inadequate CART. Eventually, we successfully gripped the top of the retrograde guidewire in the CTO lesion using the basket-shaped microsnare (Soutenir®). The microsnare may be useful for bidirectional approach in peripheral CTO lesions.

Response Prediction and Influence of Tolvaptan in Chronic Heart Failure Patients Considering the Interaction of the Renin-Angiotensin-Aldosterone System and Arginine Vasopressin

The renin-angiotensin-aldosterone system (RAAS) and arginine vasopressin (AVP) regulate body fluids. Although conventional diuretics have been used for treating heart failure, they activate RAAS and exacerbate renal function. Tolvaptan, a newly developed vasopressin-2 receptor antagonist, elicits aquaresis and improves volume overload in heart failure patients, however, the predictors of tolvaptan effectiveness and the influence on the RAAS and renal function according to tolvaptan therapy are not established. We evaluated 26 chronic heart failure patients receiving therapy with 15 mg/day tolvaptan and examined their laboratory and urinary data before and after tolvaptan therapy. A response to tolvaptan was defined as a body weight decrease by more than 2 kg in a week and a urine volume increase by 500 mL/ day compared with that before tolvaptan administration. Body weight, urine volume, and brain natriuretic peptide levels significantly improved (P < 0.05), without any worsening of renal function represented by serum creatinine, sodium, and potassium. Moreover, no significant changes were observed in the plasma renin activity and plasma aldosterone concentration (PAC). In the responder group, urine osmolality before tolvaptan administration was significantly higher (P < 0.05) but declined significantly after tolvaptan administration (P < 0.05). The AVP/PAC ratio before administration was positively correlated with the efficacy of tolvaptan. Tolvaptan treatment could prevent RAAS activation in chronic heart failure patients. Moreover, monitoring the AVP/PAC ratio may be useful in predicting the tolvaptan response.

Transdermal patch of bisoprolol for the treatment of hypertension complicated with aortic dissection

A 63-year-old man presented to a clinic because of sudden onset of severe longitudinal back pain and was transferred to the intensive care unit (ICU) of our hospital. He had been hypertensive for 30 years; however, he had never been referred to a clinic for treatment. Physical examination findings were unremarkable, except for high blood pressure (BP) (220/110mmHg) and heart rate (80 beats/min). Electrocardiography and chest radiography findings were normal. Blood examination showed leukocytosis (9700/μL) without an increased plasma fibrin degradation products level (2 μg/mL). The patient was diagnosed with acute type B aortic dissection (AD) with a thrombosed false lumen by enhanced computed tomography (Fig. 1). We administered an 8-mg/day transdermal patch of bisoprolol after titration of intravenous nicardipine (Fig. 2). Six hours later, systolic BP decreased to 112 mm Hg and heart rate decreased to 54 beats/min. Additionally, the ventricular force (dP/dt) of aortic pressure decreased over time. After intravenous nicardipine was withdrawn, 40 mg of olmesartan, 80 mg of nifedipine, and 2 mg of doxazosin in addition to the 8-mg transdermal patch of bisoprolol were administered, and systolic BP was well controlled to b120 mm Hg. He was discharged 23 days after the onset of AD without any complication. BP reduction is critical to preventing lethal complications, including enlargement of aortic aneurysm and aortic rupture in the acute phase [1]. dP/dt and stress on the aorta are risk factors, and therefore, β-blockers should be the first drug of choice because they have negative chronotropic and negative inotropic effects [2]. Maintaining systolic BP between 100 and 120 mm Hg with a heart rate b60 beats/min is an attainable temporal goal [3], which was achieved with intravenous nicardipine and transdermal bisoprolol in the present case. However, in many cases, multiple BP-lowering agents are required to achieve this goal. Intravenous agents should be chosen for controlling BP because of the need for titration of the dose, especially in patients with a

Inhibition of activated factor X by rivaroxaban attenuates neointima formation after wire-mediated vascular injury

ABSTRACT Accumulating evidence suggests that activated factor X (FXa), a key coagulation factor, plays an important role in the development of vascular inflammation through activation of many cell types. Here, we investigated whether pharmacological blockade of FXa attenuates neointima formation after wire‐mediated vascular injury. Transluminal femoral artery injury was induced in C57BL/6 mice by inserting a straight wire. Rivaroxaban (5 mg/kg/day), a direct FXa inhibitor, was administered from one week before surgery until killed. At four weeks after surgery, rivaroxaban significantly attenuated neointima formation in the injured arteries compared with control (P<0.01). Plasma lipid levels and blood pressure were similar between the rivaroxaban‐treated group and non‐treated group. Quantitative RT‐PCR analyses demonstrated that rivaroxaban reduced the expression of inflammatory molecules (e.g., IL‐1&bgr; and TNF‐&agr;) in injured arteries at seven days after surgery (P<0.05, respectively). In vitro experiments using mouse peritoneal macrophages demonstrated that FXa increased the expression of inflammatory molecules (e.g., IL‐1&bgr; and TNF‐&agr;), which was blocked in the presence of rivaroxaban (P<0.05). Also, in vitro experiments using rat vascular smooth muscle cells (VSMC) demonstrated that FXa promoted both proliferation and migration of this cell type (P<0.05), which were blocked in the presence of rivaroxaban. Inhibition of FXa by rivaroxaban attenuates neointima formation after wire‐mediated vascular injury through inhibition of inflammatory activation of macrophages and VSMC.

Effect of combination tablets containing amlodipine 10 mg and irbesartan 100 mg on blood pressure and cardiovascular risk factors in patients with hypertension.

Background Hypertension is one of the major risk factors for cardiovascular and cerebrovascular disease and mortality. Patients who receive insufficient doses of antihypertensive agents or who are poorly adherent to multidrug treatment regimens often fail to achieve adequate blood pressure (BP) control. The aim of this study was to determine the efficacy of an angiotensin II receptor blocker (ARB) and calcium channel blocker (CCB) combination tablet containing a regular dose of irbesartan (100 mg) and a high dose of amlodipine (10 mg) with regard to lowering BP and other risk factors for cardiovascular disease. Methods We retrospectively evaluated data from 68 patients with essential hypertension whose treatment regimen was changed either from combination treatment with an independent ARB and a low-dose or regular-dose CCB or from a combination tablet of ARB and a low-dose or regular-dose CCB to a combination tablet containing amlodipine 10 mg and irbesartan 100 mg, because of incomplete BP control. Previous treatments did not include irbesartan as the ARB. Results The combination tablet decreased systolic and diastolic BP. In addition, it significantly decreased serum uric acid, low-density lipoprotein cholesterol, and increased high-density lipoprotein cholesterol levels, independent of the BP-lowering effect. Treatment with the combination tablet did not affect serum triglycerides, plasma glucose, glycated hemoglobin, serum potassium or creatinine levels, or the urinary albumin excretion rate. Conclusion The combination tablet containing amlodipine 10 mg and irbesartan 100 mg had a greater BP-lowering effect than an ARB and a low-dose or regular-dose CCB. In addition, the combination tablet had more favorable effects on serum uric acid, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels in patients with hypertension.

Protease-Activated Receptor-2 Plays a Critical Role in Vascular Inflammation and Atherosclerosis in Apolipoprotein E-Deficient Mice

Background: The coagulation system is closely linked with vascular inflammation, although the underlying mechanisms are still obscure. Recent studies show that protease-activated receptor (PAR)-2, a major receptor of activated factor X, is expressed in both vascular cells and leukocytes, suggesting that PAR-2 may contribute to the pathogenesis of inflammatory diseases. Here we investigated the role of PAR-2 in vascular inflammation and atherogenesis. Methods: We generated apolipoprotein E-deficient (ApoE-/-) mice lacking systemic PAR-2 expression (PAR-2-/-ApoE-/-). ApoE-/- mice, which lack or express PAR-2 only in bone marrow (BM) cells, were also generated by BM transplantation. Atherosclerotic lesions were investigated after 20 weeks on a Western-type diet by histological analyses, quantitative reverse transcription polymerase chain reaction, and Western blotting. In vitro experiments using BM-derived macrophages were performed to confirm the proinflammatory roles of PAR-2. The association between plasma activated factor X level and the severity of coronary atherosclerosis was also examined in humans who underwent coronary intervention. Results: PAR-2-/-ApoE-/- mice showed reduced atherosclerotic lesions in the aortic arch (P<0.05) along with features of stabilized atherosclerotic plaques, such as less lipid deposition (P<0.05), collagen loss (P<0.01), macrophage accumulation (P<0.05), and inflammatory molecule expression (P<0.05) compared with ApoE-/- mice. Systemic PAR2 deletion in ApoE-/- mice significantly decreased the expression of inflammatory molecules in the aorta. The results of BM transplantation experiments demonstrated that PAR-2 in hematopoietic cells contributed to atherogenesis in ApoE-/- mice. PAR-2 deletion did not alter metabolic parameters. In vitro experiments demonstrated that activated factor X or a specific peptide agonist of PAR-2 significantly increased the expression of inflammatory molecules and lipid uptake in BM-derived macrophages from wild-type mice compared with those from PAR-2–deficient mice. Activation of nuclear factor-&kgr;B signaling was involved in PAR-2–associated vascular inflammation and macrophage activation. In humans who underwent coronary intervention, plasma activated factor X level independently correlated with the severity of coronary atherosclerosis as determined by Gensini score (P<0.05) and plaque volume (P<0.01). Conclusions: PAR-2 signaling activates macrophages and promotes vascular inflammation, increasing atherosclerosis in ApoE-/- mice. This signaling pathway may also participate in atherogenesis in humans.

Edoxaban improves acute venous thromboembolism while preserving protein C and protein S levels

BACKGROUND It is well known that warfarin inhibits the synthesis of vitamin K-dependent anticoagulants, including thrombin, protein C and S, and factor Xa, leading, paradoxically, to an initial hypercoagulable state. Edoxaban, a direct inhibitor of activated factor X is widely used for the treatment of acute venous thromboembolism (VTE). However, the effect of edoxaban on circulating coagulation factors, in patients with acute VTE, remains unknown. METHODS AND RESULTS We enrolled 57 patients with acute VTE with/without pulmonary embolism treated with edoxaban (n=37) or warfarin (n=20) in a clinical setting. Before treatment and 2 weeks after treatment, we evaluated thrombotic burden using ultrasound or computed tomography angiography. We also evaluated thrombin generation, represented by prothrombin fragment F1+2; thrombus degradation, represented by D-dimer; and levels of anticoagulants, including protein C, protein S, and antithrombin III. Both edoxaban and warfarin treatment improved thrombotic burden and decreased prothrombin fragment F1+2, and D-dimer. Edoxaban treatment preserved protein C and protein S levels. In contrast, warfarin decreased protein C and protein S levels. Neither treatment affected antithrombin III. CONCLUSIONS Edoxaban improves VTE while preserving protein C and protein S levels, thereby indicating that edoxaban improves thrombotic burden while maintaining levels of anticoagulants.