Complement Mediated Endothelial Damage in Thrombotic Microangiopathies

Thrombotic microangiopathies (TMA) constitute a group of different disorders that have a common underlying mechanism: the endothelial damage. These disorders may exhibit different mechanisms of endothelial injury depending on the pathological trigger. However, over the last decades, the potential role of the complement system (CS) has gained prominence in their pathogenesis. This is partly due to the great efficacy of complement-inhibitors in atypical hemolytic syndrome (aHUS), a TMA form where the primary defect is an alternative complement pathway dysregulation over endothelial cells (genetic and/or adquired). Complement involvement has also been demonstrated in other forms of TMA, such as thrombotic thrombocytopenic purpura (TTP) and in Shiga toxin-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS), as well as in secondary TMAs, in which complement activation occurs in the context of other diseases. However, at present, there is scarce evidence about the efficacy of complement-targeted therapies in these entities. The relationship between complement dysregulation and endothelial damage as the main causes of TMA will be reviewed here. Moreover, the different clinical trials evaluating the use of complement-inhibitors for the treatment of patients suffering from different TMA-associated disorders are summarized, as a clear example of the entry into a new era of personalized medicine in its management

Cell adhesive peptides functionalized on CoCr alloy stimulate endothelialization and prevent thrombogenesis and restenosis

Immobilization of bioactive peptide sequences on CoCr surfaces is an effective route to improve endothelialization, which is of great interest for cardiovascular stents. In this work, we explored the effect of physical and covalent immoblization of RGDS, YIGSR and their equimolar combination peptides on endothelial cells (EC) and smooth muscle cell (SMC) adhesion and on thrombogenicity. We extensively investigated using RT-qPCR, the expression by ECs cultured on functionalised CoCr surfaces of different genes. Genes relevant for adhesion (ICAM-1 and VCAM-1), vascularization (VEGFA, VEGFR-1 and VEGFR-2) and anti-thrombogenicity (tPA and eNOS) were over-expressed in the ECs grown to covalently functionalized CoCr surfaces compared to physisorbed and control surfaces. Pro-thrombogenic genes expression (PAI-1 and vWF) decreased over time. Cell co-cultures of ECs/SMCs found that functionalization increased the amount of adhered ECs onto modified surfaces compared to plain CoCr, independently of the used peptide and the strategy of immobilization. SMCs adhered less compared to ECs in all surfaces. All studied peptides showed a lower platelet cell adhesion compared to TCPS. Covalent functionalization of CoCr surfaces with an equimolar combination of RGDS and YIGSR represented prevailing strategy to enhance the early stages of ECs adhesion and proliferation, while preventing SMCs and platelet adhesion.Postprint (author's final draft

Acute Graft-vs.-Host Disease-Associated Endothelial Activation in vitro Is Prevented by Defibrotide

Altres ajuts: This study was supported in part by Jazz Pharmaceuticals Plc (IST-16-10355), German Jose Carreras Leukaemia Foundation (11R/2016 and 03R/2019).Angiogenesis and endothelial activation and dysfunction have been associated with acute graft-vs.-host disease (aGVHD), pointing to the endothelium as a potential target for pharmacological intervention. Defibrotide (DF) is a drug with an endothelium-protective effect that has been approved for the treatment of veno-occlusive disease/sinusoidal obstruction syndrome after allogeneic hematopoietic cell transplantation. Clinical data suggest that DF also reduces the incidence of aGVHD; however, the mechanisms of DF-mediated aGVHD regulation have not been examined. To investigate possible DF-mediated prophylactic and therapeutic mechanisms in aGVHD, we performed in vitro studies using endothelial cell (EC) lines. We found that DF significantly and dose-dependently suppressed EC proliferation and notably reduced their ability to form vascular tubes in Matrigel. To explore whether DF administered prophylactically or therapeutically has a significant effect on aGVHD endothelial dysfunction, ECs were exposed to media containing sera from patients with aGVHD (n = 22) in the absence or presence of DF and from patients that did not develop aGVHD (n = 13). ECs upregulated adhesion molecules (vascular cell adhesion molecule 1, intercellular adhesion molecule 1), the adherence junction protein VE-cadherin, von Willebrand factor (VWF), and Akt phosphorylation in response to aGVHD sera. These responses were suppressed upon treatment with DF. In summary, DF inhibits vascular angiogenesis and endothelial activation induced by sera from aGVHD patients. Our results support the view that DF has notable positive effects on endothelial biology during aGVHD

Prevenció de la infecció respiratòria

Infecció respiratòria; Prevenció; Atenció sanitàriaInfección respiratória; Prevención; Atención sanitáriaRespiratory infection; Prevention; Health careMonografia sobre temes concrets relacionats amb la prevenció de la infecció respiratòria relacionada amb l‟atenció sanitària. Ha estat elaborada per un comitè d‟experts amb una àmplia trajectòria en el camp de l'atenció a pacients amb problemes respiratoris. El document comença fent una posada al dia de l‟epidemiologia i l‟etiopatogènia de les infeccions respiratòries nosocomials i, sense voler repetir capítols de la monografia d'aïllaments, continua fent una pinzellada de les mesures que cal dur a terme per evitar la transmissió de les infeccions respiratòries dins dels centres sanitaris. Tot seguit, s‟aborden de manera pràctica situacions quotidianes, com el maneig de la via aèria, i es fan algunes recomanacions sobre com dur-les a terme. Una part important i poc coneguda per molts professionals és la prevenció de la infecció respiratòria de causa instrumental, motiu pel qual en el darrer capítol es fa una revisió minuciosa de com procedir per reutilitzar aquests aparells.Monografía sobre temas concretos relacionados con la prevención de la infección respiratoria con la atención sanitaria. Ha sido elaborada por un comité de expertos con una amplia trayectoria en el campo de la atención a pacientes con problemas respiratorios. El documento empieza haciendo una puesta al día de la epidemiologia y la etiopatogenia de las infecciones respiratorias nosocomiales y, sin querer repetir capítulos de la monografía de aislamientos, continua haciendo una pincelada de las medidas que son necesarias para evitar la transmisión de las infecciones respiratorias dentro de los centros sanitarios. Seguidamente se tratan de manera práctica situaciones cotidianas, como el manejo de la vía aérea y se hacen algunas recomendaciones sobre como llevarlas a cabo. Una parte importante y poco conocida para muchos profesionales es la prevención de la infección respiratoria de causa instrumental, motivo por el cual en el último capítulo se hace una revisión minuciosa de como proceder para reutilizar estos aparatos

The avoidance of G-CSF and the addition of prophylactic corticosteroids after autologous stem cell transplantation for multiple myeloma patients appeal for the at-home setting to reduce readmission for neutropenic fever

Background Autologous stem cell transplantation (ASCT) remains the standard of care for young multiple myeloma (MM) patients; indeed, at-home ASCT has been positioned as an appropriate therapeutic strategy. However, despite the use of prophylactic antibiotics, neutropenic fever (NF) and hospital readmissions continue to pose as the most important limitations in the outpatient setting. It is possible that the febrile episodes may have a non-infectious etiology, and engraftment syndrome could play a more significant role. The aim of this study was to analyze the impact of both G-CSF withdrawal and the addition of primary prophylaxis with corticosteroids after ASCT. Methods Between January 2002 and August 2018, 111 MM patients conditioned with melphalan were managed at-home beginning +1 day after ASCT. Three groups were established: Group A (n = 33) received standard G-CSF post-ASCT; group B (n = 32) avoided G-CSF post-ASCT; group C (n = 46) avoided G-CSF yet added corticosteroid prophylaxis post-ASCT. Results The incidence of NF among the groups was reduced (64%, 44%, and 24%; P2 (OR 6.1; P = 0.002) and G-CSF avoidance plus corticosteroids (OR 0.1; P60 years (OR 14.6; P = 0.04) and G-CSF avoidance plus corticosteroids (OR 0.07; P = 0.05). Conclusions G-CSF avoidance and corticosteroid prophylaxis post ASCT minimize the incidence of NF in MM patients undergoing at-home ASCT. This approach should be explored in a prospective randomized clinical trial

Differential expression of proteins from cultured endothelial cells exposed to uremic versus normal serum

[Background]: Deficient hemostasis and accelerated atherosclerosis coexist in patients with chronic kidney disease. Endothelial dysfunction may be involved in the high incidence of atherothrombotic events in these patients. We established an in vitro model of endothelial dysfunction by exposing endothelial cells to uremic media and applied a proteomic approach to characterize endothelial cell dysfunction in uremia.[Study Design]: Cross-sectional study.[Setting and Participants]: Serum samples from 8 patients with chronic kidney disease on hemodialysis treatment were collected.[Predictor]: Exposure of cultured endothelial cells to normal and uremic serum.[Outcome and Measurements]: Proteins from lysed cells were characterized by isoelectric point and molecular weight by using 2-dimensional gel electrophoresis. Spots were visualized by means of silver staining and identified by using mass spectrometry.[Results]: Identification of the most prominent proteins showed molecules related to inflammation (high mobility group box 1, aldose reductase, and proteasome components) and oxidative stress (superoxide dismutase and glutathione peroxidase), both associated with chronic kidney disease. These changes may be caused by activation of the nuclear factor-κB transcription factor. Changes in expression of cytoskeletal proteins (destrin and vimentin) also were detected.[Limitations]: In vitro study.[Conclusion]: Proteomic techniques proved to be a powerful tool to investigate endothelial dysfunction in uremia. A more exhaustive analysis will provide answers and potential therapeutic targets in the near future.This work was partially supported by grant SAF2006-08003 from the Ministerio de Ciencia y Tecnología; grants FIS PI060260, FIS PI040887, FIS CP04/00112, and FIS PI050153 from Fondo de Investigaciones de la Seguridad Social; and grant SGR2005-00952 from the Generalitat de Catalunya. Dr Carbo received grant 2006FI00092 from the Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya and Fons Social Europeu.Peer reviewe

Primary arrest of circulating platelets on collagen involves phosphorylation of Syk, cortactin and focal adhesion kinase: studies under flow conditions.

After a vessel wall injury, platelets adhere to the subendothelium following a sequence of events: arrest of single platelets on the surface, progression to platelet spreading and final aggregation. Primary arrest of circulating platelets on subendothelial components occurs through platelet glycoprotein (GP) Ib and collagen receptors; then platelets spread and aggregate through a GPIIb-IIIa-dependent mechanism. A series of strategies were applied to analyse the tyrosine-phosphorylation mechanisms occurring at the different stages of platelet adhesion on subendothelial components under flow conditions, with special attention to primary arrest. To evaluate spread platelets, samples were exposed to acetylsalicylic acid, which blocks aggregate formation. To study single platelets in contact, a monoclonal antibody specific for GPIIb-IIIa was used to prevent platelet spreading and further aggregation. This experimental situation was also investigated using blood from two patients with Glanzmann's thrombasthenia (i.e. lacking GPIIb-IIIa). Results demonstrated that blockade of both spreading and aggregation results in significant changes in the tyrosine-phosphorylation patterns. Arrest of single platelets on collagen-rich surfaces resulted in phosphorylation of p125, identified as focal adhesion kinase (FAK), the 80/85 kDa doublet (cortactin), and p72, identified as Syk. Arrest of single platelets on von Willebrand factor as adhesive substrate showed that interaction through GPIb induces Syk phosphorylation, but not that of cortactin and FAK. Our data indicate that the initial arrest of platelets on subendothelial components involves Syk phosphorylation, which seems to be GPIb-dependent, and this is followed by activation and phosphorylation of cortactin and FAK. These processes seem to occur before GPIIb-IIIa becomes activated

Role of sodium tungstate as a potential antiplatelet agent.

Purpose: Platelet inhibition is a key strategy in the management of atherothrombosis. However, the large variability in response to current strategies leads to the search for alternative inhibitors. The antiplatelet effect of the inorganic salt sodium tungstate (Na2O4W), a protein tyrosine phosphatase 1B (PTP1B) inhibitor, has been investigated in this study.Methods: Wild-type (WT) and PTP1B knockout (PTP1B-/-) mice were treated for 1 week with Na2O4W to study platelet function with the platelet function analyzer PFA-100, a cone-and-plate analyzer, a flat perfusion chamber, and thrombus formation in vivo. Human blood aliquots were incubated with Na2O4W for 1 hour to measure platelet function using the PFA-100 and the annular perfusion chamber. Aggregometry and thromboelastometry were also performed.Results: In WT mice, Na2O4W treatment prolonged closure times in the PFA-100 and decreased the surface covered (%SC) by platelets on collagen. Thrombi formed in a thrombosis mice model were smaller in animals treated with Na2O4W (4.6±0.7 mg vs 8.9±0.7 mg; P<0.001). Results with Na2O4W were similar to those in untreated PTP1B -/- mice (5.0±0.3 mg). Treatment of the PTP1B-/- mice with Na2O4W modified only slightly this response. In human blood, a dose-dependent effect was observed. At 200 mM, closure times in the PFA-100 were prolonged. On denuded vessels, %SC and thrombi formation (%T) decreased with Na2O4W. Neither the aggregating response nor the viscoelastic clot properties were affected.Conclusion: Na2O4W decreases consistently the hemostatic capacity of platelets, inhibiting their adhesive and cohesive properties under flow conditions in mice and in human blood, resulting in smaller thrombi. Although Na2O4W may be acting on platelet PTP1B, other potential targets should not be disregarded © 2015 Fernández-Ruiz et al.This work was supported by the Secretaría de Estado de Investigación, Desarrollo e Innovación, and the Ministerio de Economía y Competitividad of Spain (SAF2011-28214 and SAF2010-19527); the Red de Investigación Cardiovascular, Instituto de Salud Carlos III, of Spain (RD12/0042/0016); and the Government of Catalonia (2009 SGR 1426). BH is a recipient of a Juan de la Ciervas’ grant from the Instituto de Salud Carlos III (JCI-2011-10417)Peer Reviewe