Anti-atherogenic effects of statins: Impact on angiopoietin-2 release from endothelial cells

Beyond lipid lowering, statins are supposed to exert pleiotropic effects positively influencing the progression of atherosclerotic lesions. The development of such lesions is associated with increased release of angiopoietin-2 (Ang-2), an endothelial cell-specific protein growth factor stored in Weibel-Palade bodies (WPBs). The aim of our study was to examine whether statin pretreatment influences the release of Ang-2 from endothelial cells. Stimulation of HUVECs and HMVECs with PMA, thrombin or histamine resulted in significant release of Ang-2, as evidenced by ELISA. Pretreatment with simvastatin and mevastatin suppressed this release to basal level, while pravastatin had no effect. Simvastatin itself increased nitric oxide (NO, EC number 1.14.13.39) synthesis, measured by Griess reaction. Combining the statin pretreatment with the eNOS inhibitor L-NNA as well as bypassing the HMG-CoA reductase (EC number: 1.1.1.34) by adding mevalonic acid or geranyl pyrophosphate restored the exocytotic effect of PMA. Immunofluorescence microscopy showed that depletion of WPBs upon PMA stimulation ceased after pretreatment with simvastatin. This study demonstrates a potent suppressive effect of statins on the release of Ang-2 from endothelial cells. Regarding its harmful effects in the development of atherosclerotic lesions, our data provide further insight into the mechanisms of the anti-atherogenic potential of statins.

Selective and direct activation of human neutrophils but not eosinophils by Toll-like receptor 8

BACKGROUND

Granulocytes represent the largest fraction of immune cells in peripheral blood and are directly exposed to circulating Toll-like receptor (TLR) ligands. Although highly relevant for TLR-based therapies, because of the technical challenge, activation of the granulocyte subsets of neutrophils and eosinophils by TLR ligands is less well studied than activation of other immune cell subsets.

OBJECTIVE

The aim of this work was to study direct versus indirect neutrophil and eosinophil activation by TLR7 and TLR8 ligands.

METHODS

We used a new whole-blood assay, single cell-based cytokine detection, and highly purified primary human neutrophils and eosinophils to separate direct and indirect effects on these blood cell subsets.

RESULTS

We found indirect but not direct activation of neutrophils but not eosinophils in whole blood by using unmodified immunostimulatory RNA (isRNA; TLR7/8 ligand). In contrast, direct activation and stimulation of the respiratory burst and degranulation was seen with nuclease-stable isRNA and with the small-molecule TLR8 agonist 3M002 but not 3M001 (TLR7). Neutrophils expressed TLR8 but none of the other 2 RNA-detecting TLRs (TLR3 and TLR7).

CONCLUSIONS

Together, these results demonstrate that neutrophils are directly and fully activated through TLR8 but not TLR7. Furthermore, the results predict that the clinical utility of small-molecule TLR8 ligands or nuclease-stable RNA ligands for TLR8 might be limited because of neutrophil-mediated toxicity and that no such limitation applies for unmodified isRNA, which is known to induce desired T(H)1 activities in other immune cell subsets.

International multicentre trial protocol to assess the efficacy and safety of tenecteplase during cardiopulmonary resuscitation in patients with out-of-hospital cardiac arrest: the Thrombolysis in Cardiac Arrest (TROICA) Study

Prehospital cardiac arrest has been associated with a very poor prognosis. Acute myocardial infarction and massive pulmonary embolism are the underlying causes of out-of-hospital cardiac arrest in 50-70% of patients. Although fibrinolysis is an effective treatment strategy for both myocardial infarction and pulmonary embolism, clinical experience for this therapy performed during resuscitation has been limited owing to the anticipated risk of severe bleeding complications. The TROICA study is planned as one of the largest randomized, double-blind, placebo-controlled trials to assess the efficacy and safety of prehospital thrombolytic therapy in cardiac arrest of presumed cardiac origin. Approximately 1000 patients with cardiac arrest will be randomized at approximately 60 international study centres to receive either a weight-adjusted dose of tenecteplase or placebo after the first dose of a vasopressor. Patients can be included if they are at least 18 years, presenting with a witnessed cardiac arrest of presumed cardiac origin, and if either basic life support had started within 10 min of onset and had been performed up to 10 min or advanced life support is started within 10 min of onset of cardiac arrest. Primary endpoint of the study is the 30-day survival rate, and the coprimary endpoint is hospital admission. Secondary endpoints are the return of spontaneous circulation (ROSC), survival after 24 h, survival to hospital discharge, and neurological performance. Safety endpoints include major bleeding complications and symptomatic intracranial haemorrhage.

Naftidrofuryl can enhance the quality of life in patients with intermittent claudication

BACKGROUND

Using a disease specific questionnaire, the CLAU-S, we undertook a double blind, placebo controlled study in patients with intermittent claudication to determine whether the increase in the pain-free walking distance, previously demonstrated with naftidrofuryl, is reflected as an improvement in the patients' quality of life.

PATIENTS AND METHODS

287 patients, with stable intermittent claudication for at least 3 months were entered into the study. Following an initial one month placebo run-in, patients were randomised to either naftidrofuryl, at a dosage of 200 mg three times daily, or matching placebo, for 6 months. All patients completed the self-administered CLAU-S questionnaire which is divided into 6 dimensions, before the start of treatment, at 3 and 6 months. Statistical analysis was undertaken on an intention-to-treat (ITT) basis which included all patients know to have taken at least one dose of the drug and to have provided key data on at least one occasion after baseline. For each of the CLAU-S dimensions the two groups were compared with respect to difference between the initial and final values.

RESULTS

255 patients (133 naftidrofuryl, 122 placebo) were eligible for the ITT analysis. Significant improvements, in favour of the active medication, were seen for the dimensions "daily living", "pain", "disease specific anxiety" and "mood". A multivariate analysis of covariance, which took into account such factors as initial score, age and sex confirmed the global superiority of naftidrofuryl (p = 0.004).

CONCLUSIONS

In this placebo controlled study, using a disease specific questionnaire, naftidrofuryl has been shown to significantly improve several aspects of the quality of life of patients with intermittent claudication.