Inhibition of the cannabinoid receptor CB(1) (CB(1)-R) exerts numerous positive cardiovascular effects such as modulation of blood pressure, insulin sensitivity and serum lipid concentrations. However, direct vascular effects of CB(1)-R inhibition remain unclear. CB(1)-R expression was validated in vascular smooth muscle cells (VSMCs) and aortic tissue of mice. Apolipoprotein E-deficient (ApoE-/-) mice were treated with cholesterol-rich diet and the selective CB(1)-R antagonist rimonabant or vehicle for 7 weeks. CB(1)-R inhibition had no effect on atherosclerotic plaque development, collagen content and macrophage infiltration but led to improved aortic endothelium-dependent vasodilation and decreased aortic reactive oxygen species (ROS) production and NADPH oxidase activity. Treatment of cultured VSMC with rimonabant resulted in reduced angiotensin II-mediated but not basal ROS production and NADPH oxidase activity. CB(1)-R inhibition with rimonabant and AM251 led to down-regulation of angiotensin II type 1 receptor (AT1-R) expression, whereas stimulation with the CB(1)-R agonist CP 55,940 resulted in AT1-R up-regulation, indicating that AT1-R expression is directly regulated by the CB(1)-R. CB(2)-R inhibition had no impact on AT1-R expression in VSMC. Consistently, CB(1)-R inhibition decreased aortic AT1-R expression in vivo. CB(1)-R inhibition leads to decreased vascular AT1-R expression, NADPH oxidase activity and ROS production in vitro and in vivo. This antioxidative effect is associated with improved endothelial function in ApoE-/- mice, indicating beneficial direct vascular effects of CB(1)-R inhibition.

IntroductionAtherosclerosis is a chronic inflammatory disease characterized by endothelial cell damage, infiltration, proliferation and accumulation of macrophages, lymphocytes and transformed vascular smooth muscle cells within the vascular wall and procoagulation processes involving activation of plasmatic coagulation events and platelets. Numerous studies suggested a close interaction between thrombin action and atherogenesis, but possibly underlying mechanisms are multiple and specific treatment options were missing until now.Material and methodsAtherosclerosis prone 12 weeks old ApoE–/– mice were fed a cholesterol rich diet for 4 weeks and were concomitantly treated orally with placebo or the thrombin inhibitor dabigatran (1.2 g/kg/day).ResultsThe thrombin time (HEMOCLOT®) was significant extended in dabigatran treated animals. Vascular oxidative stress was significantly reduced during thrombin inhibition, as assessed by L012 chemiluminescence in aortic segments (212 ±84 vs. 69 ±21 RLU/s/mg dry weight, p = 0.048). Organ chamber experiments of isolated aortic rings showed that dabigatran treatment significantly improved endothelium-derived vasorelaxation (p < 0.001). Dabigatran treated mice developed less atherosclerotic lesions (6.2 ±0.2% vs. 9 ±1.1%, p = 0.037) and showed less infiltration of atherosclerotic lesions with macrophages (2.59 ±0.3% vs. 5.14 ±0.7%, p = 0.0046), as determined by systematic histological and immunohistological analyses of the aortic root. Blood pressure, body weight and food intake were not altered by the treatment.ConclusionsThe thrombin inhibitor dabigatran reduces vascular oxidative stress and inflammation, improves endothelial function and decreases atherosclerosis in mice.

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Background A decline in hospitalization for cardiovascular events and catheter laboratory activation was reported for the United States and Italy during the initial stage of the Covid-19 pandemic of 2020. We report on the deployment of emergency services for cardiovascular events in a defined region in western Germany during the government-imposed lock-down period. Methods We examined 5799 consecutive patients who were treated by emergency services for cardiovascular events during the Covid-19 pandemic (January 1 to April 30, 2020), and compared those to the corresponding time frame in 2019. Examining the emergency physicians’ records provided by nine locations in the area, we found a 20% overall decline in cardiovascular admissions. Results The greatest reduction could be seen immediately following the government-imposed social restrictions. This reduction was mainly driven by a reduction in discretionary admissions for dizziness/syncope (-53%), heart failure (-38%), exacerbated COPD (-28%) and unstable angina (-23%), while unavoidable admissions for ST-elevation myocardial infarction (STEMI), cardiopulmonary resuscitation (CPR) and stroke were unchanged. There was a greater decline in emergency admissions for patients ≥60 years. There was also a greater reduction in emergency admissions for those living in urban areas compared to suburban areas. Conclusions During the Covid-19 pandemic, a significant decline in hospitalization for cardiovascular events was observed during the government-enforced shutdown in a predefined area in western Germany. This reduction in admissions was mainly driven by “discretionary” cardiovascular events (unstable angina, heart failure, exacerbated COPD and dizziness/syncope), but events in which admission was unavoidable (CPR, STEMI and stroke) did not change.

IntroductionCardiogenic shock (CS) remains the leading cause of death in patients hospitalized for myocardial infarction (MI). Systemic inflammation with inappropriate vasodilatation is observed in many patients with CS and may contribute to an excess mortality rate. The purpose of this study was to determine the predictive role of serial measurements of Nt-proBNP, interleukin-6 (IL-6), and procalcitonin (PCT) for 30-day mortality in patients with CS due to MI.MethodsThe present study is a prospective single-center study including 87 patients with MI complicated by CS treated with acute revascularization and intraaortic balloon counterpulsation (IABP) support. Predictive values of plasma levels at admission (T0), after 24 hours (T1), and after 72 hours (T2) were examined according to 30-day mortality.ResultsSignificant differences between survivors (n = 59) and nonsurvivors (n = 28) were seen for Nt-proBNP at T0, for IL-6 at T0 and T1, and for PCT at T1 and T2. According to ROC analyses, the highest accuracy predicting 30-day mortality was seen at T0 for IL-6, at T1 for PCT, and at T2 for PCT. In univariate analysis, significant values were found for Nt-proBNP at T1, and for IL-6 and PCT at all points in time. Within the multivariate analysis, age, creatinine, and IL-6 were significant determinants of 30-day mortality, in which IL-6 showed the highest level of significance.ConclusionsIn patients with MI complicated by CS, IL-6 represented a reliable independent early prognostic marker of 30-day mortality. PCT revealed a significant value at later points in time, whereas Nt-proBNP seemed to be of lower relevance.

The renin-angiotensin-aldosterone system (RAAS) is part of the blood pressure regulating system. Its main effector peptide is angiotensin II (Ang II). Although it may induce hypertension, the proinflammatory, profibrotic, and prothrombotic effects are mainly mediated by effects of Ang II on the cellular and molecular level that are independent of blood pressure. Therefore, pharmacotherapeutic intervention within the RAAS is an important treatment modality for patients suffering from cardiovascular diseases, even those who are not hypertensive. In addition to the blood pressure lowering and vasculoprotective (pleiotropic) effects of angiotensin II type 1 (AT(1)) receptor blockers (ARBs), and angiotensin-converting enzyme (ACE) inhibitors, regenerative progenitor cell therapy emerges as an auxiliary therapy to improve regeneration of the vascular endothelium. This review focuses on the growing knowledge about regenerating vascular cells, their response to RAAS effectors, and RAAS-modulating pharmacotherapy in the context of endothelial cell damage and regeneration.

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