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Stent thrombosis (ST) is a catastrophic event and efforts to reduce its incidence by altering blood-stent interactions are longstanding. A new electret coating technology that produces long-lasting negative charge on stent surface could make them intrinsically resistant to thrombosis. We assessed the thrombogenicity of stents using an annular perfusion model with confocal microscopy, and determined the efficacy of electret coating technology to confer thrombo-resistant properties to standard stents. Using an annular perfusion chamber, Bare Metal Stent (BMS), standard uncoated DES (DES), and Electret-coated DES (e-DES) were exposed to human blood under arterial flow conditions. Deposits of fibrinogen and platelets on the stent surface were analyzed using immunofluorescence staining and confocal microscopy. Surface coverage by fibrinogen and platelets and the deposit/aggregate size were quantified using computerized morphometric analysis. The experimental methodology produced consistent, quantifiable results. Area of stent surface covered by fibrinogen and platelets and the average size of the deposits/aggregates were lowest for e-DES and highest on BMS, with DES in the middle. The size of fibrinogen–deposits showed no differences between the stents. The testing methodology used in our study successfully demonstrated that electret coating confers significant antithrombotic property to DES stents. These findings warrant confirmation in a larger study. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2DM) is one of the most common chronic health conditions in the USA; it affects approximately 10% of adults with up to one-quarter being undiagnosed. T2DM is associated with substantial cardiovascular (CV) morbidity and mortality. T2DM is a pathological condition characterized by elevated levels of glucose and associated with high CV risk. Traditional hypoglycemic drugs have demonstrated their capability for effective and maintained management of high glucose levels, but they have not significantly impacted on the incidence of CV events. Recently, a new class of hypoglycemic agents, SGLT-2 receptor inhibitors, has been developed. The EMPA-OUTCOME trial involving empagliflozin (a SGLT-2 receptor inhibitor) has shown significant reductions in major adverse cardiac events (MACEs), cardiovascular mortality, and hospitalization for heart failure (HF) when administered on top of standard-of-care therapy for T2DM patients at high CV risk. The dramatic change driving the superiority of the primary composite outcome (major adverse CV events) was a significantly lower CV death rate (38% relative risk reduction). In addition, there were also an impressive 35 and 32% relative risk reductions in hospitalization for heart failure (HF) and death from any cause, respectively. These effects are even more important given the difficulties for treating concomitant HF in T2DM patients. These surprising results have been also corroborated by another agent of this class, canagliflozin, and the CANVAS trial. The magnitude of these somehow surprising cardiac benefits attained in the absence of major differences in glycemic, lipid, or blood pressure (BP) control has led to several groups to suggest that these benefits may be independent of its hypoglycemic activity and whether this new class could be considered a “cardiac” drug. The objective of this review has been to review the different hypotheses proposed to explain the cardiac benefits of this new class of antidiabetic drugs. [ABSTRACT FROM AUTHOR]

Introduction: Mechanisms of action of direct oral anticoagulants (DOAC) suggest a potential therapeutic use in the prevention of thrombotic complications in arterial territories. However, effects of DOACs on platelet activation and aggregation have not been explored in detail. We have investigated the effects of apixaban on platelet and fibrin components of thrombus formation under static and flow conditions. Methods: We assessed the effects of apixaban (10, 40 and 160 ng/mL) on: 1) platelet deposition and fibrin formation onto a thrombogenic surface, with blood circulating at arterial shear-rates; 2) viscoelastic properties of forming clots, and 3) thrombin generation in a cell-model of coagulation primed by platelets. Results: In studies with flowing blood, only the highest concentration of apixaban, equivalent to the therapeutic Cmax, was capable to significantly reduce thrombus formation, fibrin association and platelet-aggregate formation. Apixaban significantly prolonged thromboelastometry parameters, but did not affect clot firmness. Interestingly, results in a platelet-based model of thrombin generation under more static conditions, revealed a dose dependent persistent inhibitory action by apixaban, with concentrations 4 to 16 times below the therapeutic Cmax significantly prolonging kinetic parameters and reducing the total amount of thrombin generated. Conclusions: Our studies demonstrate the critical impact of rheological conditions on the antithrombotic effects of apixaban. Studies under flow conditions combined with modified thrombin generation assays could help discriminating concentrations of apixaban that prevent excessive platelet accumulation, from those that deeply impair fibrin formation and may unnecessarily compromise hemostasis. [ABSTRACT FROM AUTHOR]

Presents a study to review mechanisms of platelet activation and aggregation and the role of the glyco-protein (GP) llb/llla receptor in the acute coronary syndromes and to summarize completed clinical trials of GP/llb/llla receptor antagonists. Data sources; Study selection; Data extraction; Data synthesis; Conclusions.

We have studied the plasma lipid and apolipoprotein profiles of 19 patients with intestinal failure who are receiving long-term total parenteral nutrition (TPN). These patients had significantly reduced levels of total and HDL cholesterol and normal levels of triglycerides. Radio-immunoassay determination of apolipoproteins showed a 30% and 50% reduction in apo A-I and A-II levels, respectively. Apolipoprotein B was normal in all but three patients. Isoelectric focusing showed two major isoforms of apo A-I in patients as compared with four isoforms observed in normal subjects and one major isoform of apo A-Il compared with multiple isoforms. Recent epidemiologic studies indicate that an increased apo B:apo A-I ratio may be an important factor in atherogenesis. We suggest that patients with small-bowel syndrome who are currently on TPN may be at greater risk for atherosclerosis. Since TPN has restored a reasonably normal life expectancy for these patients, long-term follow-up will likely provide answers. [ABSTRACT FROM AUTHOR]

Sickle cell disease (SCD) is a genetic disease caused by mutations in the beta globin gene, and inflammation plays a key role in driving many aspects of disease pathology. Early immune activation is believed to be associated with hemodynamic stresses and thrombus formation as cells traffic through blood vessels. We applied an extracorporeal perfusion system to model these effects ex vivo, and combined this with a phospho-CyTOF workflow to comprehensively evaluate single-cell signatures of early activation across all major circulating immune subsets. These approaches showed immune activation following passage through the perfusion chamber, most notably in monocytes, which exhibited platelet aggregation and significantly elevated expression of multiple phospho-proteins. Overall, these studies outline a robust and broadly applicable workflow to leverage phospho-CyTOF to characterize immune activation in response to ex vivo or in vivo perturbations and may facilitate identification of novel therapeutic targets in SCD and other inflammatory diseases. [ABSTRACT FROM AUTHOR]

The propensity of plaque to disrupt is a major determinant of future ischemic events. Although they are distinct from one another, the atherosclerotic and thrombotic processes appear to be interdependent and may be integrated under the term “atherothrombosis.” It is now clear that plaque composition, rather than the percent stenosis, is a major determinant of plaque vulnerability. Plaque disruption seems to depend on both passive and active phenomena and is not purely mechanical. Inflammation (activation of monocytes/macrophages) is a major determinant of both plaque vulnerability and thrombogenicity as they relate to plaque disruption. In one-third of acute coronary syndromes, there is, however, no plaque disruption but only superficial erosion of a markedly stenotic, fibrotic plaque. In these cases, thrombus formation may be exacerbated by a hyperthrombogenic state present in patients with certain systemic risk factors. The endothelium plays a pivotal role in vascular homeostasis and hemostasis. This dynamic organ regulates blood thrombogenicity as well as contractile, secretory, and mitogenic activities in the vessel wall. Some classic risk factors induce endothelial dysfunction by reducing the bioavailability of nitric oxide, increasing tissue endothelin-1, and activating pro-inflammatory signaling pathways. Vascular hemostasis, which is the maintenance of blood fluidity and vascular integrity, is achieved by counter-balancing the intrinsic clotting tendency of blood. As a consequence of the central role of endothelial cells in hemostatic control, a dysfunctional endothelium will generate a pro-thrombotic environment favoring development of atherosclerotic lesions and thrombotic complications. [Copyright &y& Elsevier]