Lipid rafts are essential for release of phosphatidylserine-exposing extracellular vesicles from platelets.

Platelets protect the vascular system during damage or inflammation, but platelet activation can result in pathological thrombosis. Activated platelets release a variety of extracellular vesicles (EVs). EVs shed from the plasma membrane often expose phosphatidylserine (PS). These EVs are pro-thrombotic and increased in number in many cardiovascular and metabolic diseases. The mechanisms by which PS-exposing EVs are shed from activated platelets are not well characterised. Cholesterol-rich lipid rafts provide a platform for coordinating signalling through receptors and Ca2+ channels in platelets. We show that cholesterol depletion with methyl-β-cyclodextrin or sequestration with filipin prevented the Ca2+-triggered release of PS-exposing EVs. Although calpain activity was required for release of PS-exposing, calpain-dependent cleavage of talin was not affected by cholesterol depletion. P2Y12 and TPα, receptors for ADP and thromboxane A2, respectively, have been reported to be in platelet lipid rafts. However, the P2Y12 antagonist, AR-C69931MX, or the cyclooxygenase inhibitor, aspirin, had no effect on A23187-induced release of PS-exposing EVs. Together, these data show that lipid rafts are required for release of PS-exposing EVs from platelets.Isaac Newton Trust/ Wellcome Trust ISSF/University of Cambridge Joint Research Grant British Heart Foundation grant SP/15/7/3156

Review of a basal insulin regimen in long-term care

Diabetes management continues to present challenges in the long-term care setting. Hypoglycemia, poor glycemic control, and high costs are associated with use of sliding-scale insulin. Evidence supporting the use of basal insulin in combination with prandial bolus and or oral agents is now available, but actual guidelines for practice are lacking for long-term care residents. Best practices are essential to achieve glycemic control and reduce costs associated with diabetes and diabetic complications in the elderly long-term care resident. A basal-bolus insulin regimen is presented that can improve management of diabetes and be cost-effective.Journal ArticlePublishe

¿Antidepresivos glutamatérgicos? las sorprendentes propiedades antidepresivas de la quetamina

This work has been financed by the SAF2007-62378 project and by the Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM)Peer Reviewe

Tick Saliva Protein Evasin-3 Allows for Visualization of Inflammation in Arteries through Interactions with CXC-Type Chemokines Deposited on Activated Endothelium

Atherosclerosis is one of the leading causes of mortality in developed and developing countries. The onset of atherosclerosis development is accompanied by overexpression of several inflammatory chemokines. Neutralization of these chemokines by chemokine-binding agents attenuates atherosclerosis progression. Here, we studied structural binding features of the tick protein Evasin-3 to chemokine (C-X-C motif) ligand 1 (CXCL1). We showed that Evasin-3-bound CXCL1 is unable to activate the CXCR2 receptor, but retains affinity to glycosamino-glycans. This observation was exploited to detect inflammation by visualizing a group of closely related CXC-type chemokines deposited on cell walls in human endothelial cells and murine carotid arteries by a fluorescent Evasin-3 conjugate. This work highlights the applicability of tick-derived chemokine-binding conjugates as a platform for the development of new agents for inflammation imaging.</p

JAM-A is a multifaceted regulator in hepatic fibrogenesis, supporting LSEC integrity and stellate cell quiescence

BACKGROUND AND AIMS: Leukocyte infiltration is a hallmark of hepatic inflammation. The Junctional Adhesion Molecule A (JAM-A) is a crucial regulator of leukocyte extravasation and is upregulated in human viral fibrosis. Reduced shear stress within hepatic sinusoids and the specific phenotype of liver sinusoidal endothelial cells (LSEC) cumulate in differing adhesion characteristics during liver fibrosis. The aim of this study was to define the functional role of cell-specific adhesion molecule JAM-A during hepatic fibrogenesis. METHODS: Complete, conditional (intestinal epithelial; endothelial) and bone marrow chimeric Jam-a knockout animals and corresponding C57Bl/6 wild-type animals were treated with carbon tetrachloride (CCl4 , 6 weeks). For functional analyses of JAM-A, comprehensive in vivo studies, co-culture models and flow-based adhesion assays were performed. RESULTS: Complete and bone marrow-derived Jam-a-/- animals showed aggravated fibrosis with increased non-sinusoidal, perivascular accumulation of CD11b+ F4/80+ monocyte-derived macrophages in contrast to wild-type mice. Despite being associated with disturbed epithelial barrier function, an intestinal epithelial Jam-a knockout did not affect fibrogenesis. In endothelial-specific Jam-a-/- animals, liver fibrosis was aggravated alongside sinusoid capillarization and hepatic stellate cell (HSC) activation. HSC activation is induced via Jam-a-/- LSEC-derived secretion of soluble factors. Sinusoid CD31 expression and hedgehog gene signalling were increased, but leukocyte infiltration and adhesion to LSECs remained unaffected. CONCLUSIONS: Our models decipher cell-specific JAM-A to exert crucial functions during hepatic fibrogenesis. JAM-A on bone marrow-derived cells regulates non-sinusoidal vascular immune cell recruitment, while endothelial JAM-A controls liver sinusoid capillarization and HSC quiescence

Leakage of astrocyte-derived extracellular vesicles in stress-induced exhaustion disorder : a cross-sectional study

Patients with stress-induced exhaustion disorder (SED) demonstrate cognitive dysfunction similar to patients with minor traumatic brain injury (TBI). We have previously detected elevated concentrations of astrocyte-derived extracellular vesicles (EVs) in patients with TBI. As such, we hypothesized that astrocyte-derived EVs could be higher in patients with SED than in patients with major depressive disorder (MDD) and healthy controls. Patients with SED (n=31), MDD (n=31), and healthy matched controls (n=61) were included. Astrocyte-derived EVs (previously known as microparticles) were measured in plasma with flow cytometry and labeled against glial fibrillary acidic protein (GFAP) and aquaporin 4 (AQP4). In addition, platelet EVs and their CD40 ligand expression were measured. Patients with SED had significantly higher concentrations of AQP4 and GFAP-positive EVs and EVs co-expressing AQP4/GFAP than patients with MDD and healthy controls. Patients with MDD had significantly higher concentrations of GFAP-positive EVs and EVs co-expressing AQP4/GFAP than healthy controls. Platelet EVs did not differ between groups. CD40 ligand expression was significantly higher in patients with SED and MDD than in controls. In conclusion, the present study suggests that patients with SED, and to some extent, patients with MDD, have increased leakage of astrocyte-derived EVs through the blood-brain barrier

Ability of Platelet-Derived Extracellular Vesicles to Promote Neutrophil-Endothelial Cell Interactions.

We tested the ability of platelet-derived extracellular vesicles (PEV) to promote adhesion of flowing neutrophils to endothelial cells (EC). PEV were collected from platelets stimulated with collagen-related peptide, and differential centrifugation was used to collect larger vesicles enriched for platelet membrane microvesicles (PMV) or smaller vesicles enriched for platelet exosomes (Pexo). Vesicle binding and resultant activation of neutrophils and EC were assessed by flow cytometry. Flow-based adhesion assays assessed binding of neutrophils directly to deposited vesicles or to EC, after neutrophils or EC had been treated with vesicles. PEV bound efficiently to neutrophils or EC, with resultant upregulation of activation markers. Binding was Ca-dependent and dominantly mediated by CD62P for neutrophils or by integrins for EC. Deposited PEV supported mainly transient attachments of flowing neutrophils through CD62P and some stable adhesion through CXC-chemokines. Neutrophil adhesion to EC was promoted when either cell was pre-treated with PEV, although the effect was less prominent when EC were pre-activated with tumor necrosis factor-α. The pro-adhesive effects on neutrophils could largely be attributed to the larger PMV rather than Pexo. Thus, surface-bound PEV can capture flowing neutrophils, while PEV also activate neutrophils and EC to promote interactions. PEV may potentiate inflammatory responses after tissue injury