Vascular pharmacology
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Vascular pharmacology · Sep 2013
ReviewThe new oral anticoagulants in atrial fibrillation: once daily or twice daily?
The new anticoagulants (NOACs) tested for prevention or treatment of venous thromboembolism (VTE), stroke prevention in atrial fibrillation (AF), and acute coronary syndromes (ACS) differ in bioavailability, metabolism, route of excretion and interaction with other drugs, but have remarkably similar pharmacokinetics, with very similar half lives. However the choice of dosing regimens in different clinical conditions has been different for the various NOACs, and has been established on the basis of widely different considerations, including the clinical setting (venous versus arterial thrombosis), the indications (prophylaxis versus treatment), the likelihood of concomitant antiplatelet drugs, and marketing opportunities; these latter were based on the knowledge that patients' compliance is generally better with once daily than with twice daily dosing. ⋯ Higher rates of bleeding have been also reported with the twice daily versus once daily dosing of darexaban in a phase II study in ACS. These results may lead to a rethinking on the pathophysiology of bleeding in the setting of anticoagulation.
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Vascular pharmacology · Sep 2013
Alteration of endothelial proteoglycan and heparanase gene expression by high glucose, insulin and heparin.
Heparan sulfate proteoglycans (HSPGs) contain a core protein with glycosaminoglycans attached. Reduced glycosaminoglycan, in endothelial HSPGs syndecan and perlecan, is associated with diabetic cardiovascular complications but changes in core protein remain controversial. Since heparanase degrades heparan sulfate, we wished to determine if changes in endothelial heparanase mRNA, by high glucose (HG), correlate with changes in syndecan and perlecan core proteins, and to observe effects of heparin or insulin. ⋯ HG plus heparin and insulin increased heparanase and syndecan mRNA compared to all other treatments and decreased perlecan mRNA compared to control and HG alone. Heparin may protect endothelium from HG injury by reducing heparanase and increasing syndecan while insulin inhibits heparanase expression. Effects with insulin plus heparin suggest interference in transcriptional regulation of heparanase and syndecan genes.