Els macròfags perivasculars i la infiltració leucocitària en la isquèmia cerebral

[cat] La isquèmia cerebral es produeix com a conseqüència de la reducció sobtada del flux sanguini en una zona del cervell a causa de l'oclusió d'una artèria cerebral. En aquesta patologia vascular cerebral es produeixen una sèrie d'esdeveniments coordinats en el temps que permeten diferenciar una primera fase aguda caracteritzada per una resposta inflamatòria accentuada seguida d'una fase subaguda i una fase crònica on es produeixen processos de resolució i reparació tissular. En les diferents fases es veuen involucrades diferents cèl·lules del sistema immunitari, així com també les pròpies cèl·lules del sistema nerviós. El principal objectiu d'aquesta tesi doctoral ha estat esbrinar els mecanismes implicats en la infiltració de leucòcits al cervell isquèmic i la seva contribució a la lesió cerebral i dèficit neurològic. El primer treball estudia la migració dels neutròfils al cervell isquèmic, les vies anatòmiques implicades i la seva infiltració en el parènquima cerebral afectat. Els resultats identifiquen, tant en models experimentals en ratolí com en mostres post-mortem de pacients amb ictus, una nova via d'entrada de leucòcits al cervell isquèmic a través de les leptomeninges i els espais de Virchow-Robin, on s'acumulen, s'activen, desenvolupen processos de degranulació i formació de NETs i finalment s'infiltren al parènquima cerebral. El treball mostra la capacitat dels neutròfils d'accedir al cervell a través de les leptomeninges sense necessitat de creuar la barrera hematoencefàlica intracerebral, la qual cosa pot tenir importància a l'hora de dissenyar estratègies per prevenir la infiltració d'aquestes cèl·lules al cervell. El segon treball posa de manifest que l'atracció de neutròfils als espais perivasculars després de la isquèmia està intervinguda, al menys en part, per l'activació dels macròfags perivasculars en resposta a la hipòxia. Aquesta resposta modifica el patró d'expressió gènica, generant quimiocines i VEGF, pel que contribueix al trencament de la barrera hematoencefàlica. La depleció dels macròfags perivasculars mitjançant injecció intracerebroventricular de liposomes amb clodronat redueix la infiltració de neutròfils, atenua la disrupció de la barrera hematoencefàlica i millora la funció neurològica en la fase aguda de la isquèmia cerebral. Finalment, el tercer treball identifica un paper beneficiós i pro-reparador dels macròfags infiltrants al cervell isquèmic mitjançat per la seva activitat proangiogènica que afavoreix l'aparició de nous vasos cerebrals en les fases cròniques que segueixen a una etapa proinflamatòria inicial i transitòria. Aquest estudi també mostra que la població de monòcits CCR2+ infiltrants al cervell isquèmic és fenotípicament heterogènia i suggereix que els macròfags amb potencial angiogènic no es troben en la medul·la òssia. Aquests resultats poden ser rellevants pel disseny de teràpies cel·lulars basades en cèl·lules mieloides. Globalment aquesta tesi mostra el paper actiu dels leucòcits en la progressió de la lesió isquèmica, la migració de neutròfils al parènquima afectat i el paper dels macròfags residents en aquest procés, la capacitat dels macròfags perivasculars de desestabilitzar la barrera hematoencefàlica en la fase aguda de la isquèmia, i, a més llarg termini, el paper proangiogènic i reparador dels macròfags infiltrants. L'estudi suggereix que alguns components de l'etapa inflamatòria inicial induïda per la isquèmia poden ser necessaris per a desencadenar processos posteriors de reparació tissular.[eng] Cerebral ischemia occurs as a result of a sudden reduction of blood flow to a brain area due to occlusion of a cerebral artery. In this cerebrovascular disease, a series of time-coordinated events take place: an acute phase characterized by an accentuated inflammatory response, followed by a subacute and a chronic phase in which tissue resolution and repair processes develop. Different cells of the immune system are involved in these different phases, as well as cells of the nervous system. The main objective of this doctoral dissertation was to elucidate the mechanisms involved in leukocyte infiltration into the ischemic brain and its contribution to brain injury and neurological deficit. The first work shows the ability of neutrophils to accumulate in the leptomeninges and in Virchow-Robin spaces, where they activate, and to ultimately access the ischemic brain parenchyma without having to cross the blood brain barrier. The second work highlights how the depletion of perivascular macrophages by intracerebroventricular injection of liposomes carrying clodronate reduces neutrophil infiltration, attenuates disruption of the blood-brain barrier, and improves neurological function in the acute phase of cerebral ischemia. The third work identifies a beneficial and pro-reparative role of brain-infiltrating macrophages mediated by their proangiogenic activity that favours the emergence of new cerebral vessels in the chronic phase after ischemic stroke. This work also unveils the phenotypic heterogeneity of CCR2+ infiltrating monocytes and suggests that the proangiogenic macrophages are not bone marrow-derived. Overall, this thesis shows the active role of leukocytes in the progression of ischemic injury, the migration of neutrophils to the affected brain parenchyma, the role of resident macrophages in this process, the ability of perivascular macrophages to destabilize the blood-brain barrier in the acute phase of the ischemia, and, in the longer term, the proangiogenic and reparative role of infiltrating macrophages. The study suggests that some components of the ischemia-induced early inflammatory stage may be needed to trigger subsequent tissue repair processes

Los riesgos laborales viales. Las rotondas como paradigma de la moderación del tráfico en los planes de movilidad de las empresas

EL reconocimiento cada vez más extendido a nivel internacional de que los accidentes de tráfico sufridos por los trabajadores en determinadas circunstancias tengan consideración de accidente laboral con todas las prestaciones sanitarias y administrativas que ello conlleva, han abierto las puertas a una nueva especialidad en el campo de la prevención de riesgos laborales: la seguridad laboral vial. Nuestra investigación se ha centrado en los aspectos de moderación de la circulación en polígonos industriales y zonas empresariales en los que existen intersecciones de vías con tráfico de vehiculos y personas y en la grandes ventajas que suponen la utilización de las rotondas como elemento clave de acoplamiento del ritmo de los movimientos de los trabajadores a las condiciones necesarias de seguridad en sus funciones. Este trabajo se basa en la aplicación de parte de la investigación sobre rotondas realizada por Jordi Xiqués Truiquell cuya presentación en el Congreso de Prevención de Riesgos Laborales quiere mostrar la polivalencia de los resultados para poderlos extender también al ámbito laboral.Postprint (published version

Effect of OAS genes on SARS-CoV-2 infection and the induction of innate immune responses

Resumen del trabajo presentado en el 8th European Congress of Virology, celebrado en Gdańsk (Polonia), del 4 al 7 de mayo de 2023Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) infections cause different clinical symptoms ranging from asymptomatic patients to patients suffering severe respiratory disease leading to death in some of them. Genetic and functional studies have shown inborn-errors of interferon (IFN)-related genes in severe COVID-19 patients explaining why some young patients devoid of co-morbidities succumbed to infection. In addition, very large genomic studies identified common genetic variants affecting the expression and splicing of IFN-stimulated genes (ISGs) of the 2",5"- oligoadenylate (2-5A) synthetase (OAS) family associated with COVID-19 severity. We have sequenced the whole genome of 274 patients who required hospitalization after SARS-CoV-2 infection, finding ultrarare mutations in OAS1 and OAS3 genes. Upon double-stranded (ds)RNA binding, the OAS1, OAS2, and OAS3 proteins synthetize 2¿- 5¿olygoadenylates which activate the endonuclease RNAseL. This endonuclease degrades viral and cellular RNAs, inhibiting viral replication. We have analyzed the effect of OAS1 and OAS3 genetic variants identified in our patients, and found that some of them impair the RNAseL activation. In addition, by using OAS3 knock-out cells generated in our laboratory and performing overexpression experiments, we have shown that OAS3 negatively modulates proinflammatory responses induced by immune challenges, and that the activation of the RNAseL activity seems necessary for this function. In addition, by using OAS3 knock-out mice infected with SARS-CoV-2 or treated with the double-stranded RNA analog poly(I:C), we have shown that OAS3 deficiency leads to a higher mouse susceptibility to SARS-CoV-2 infection and that OAS3 counteracts the induction of innate immune responses in the mouse infectedlungs, leading to a higher inflammatory response in OAS3 knock-out mice, compared to the parental mice. Given the contribution of exacerbated inflammatory responses to COVID-19 disease severity, our results suggest that OAS1/OAS3 could play a role limiting the severity of the clinical symptoms after SARS-CoV-2 infection

Systems analysis reveals complex biological processes during virus infection fate decisions

The processes and mechanisms of virus infection fate decisions that are the result of a dynamic virus-immune system interaction with either an efficient effector response and virus elimination or an alleviated immune response and chronic infection are poorly understood. Here we characterized the host response to acute and chronic lymphocytic choriomeningitis virus (LCMV) infections by gene coexpression network analysis of time-resolved splenic transcriptomes. We found first, an early attenuation of inflammatory monocyte/macrophage prior to the onset of T cell exhaustion and second, a critical role of the XCL1-XCR1 communication axis during the functional adaptation of the T cell response to the chronic infection state. These findings not only reveal an important feedback mechanism that couples T cell exhaustion with the maintenance of a lower level of effector T cell response but also suggest therapy options to better control virus levels during the chronic infection phase.info:eu-repo/semantics/publishedVersio

CNS-border associated macrophages respond to acute ischemic stroke attracting granulocytes and promoting vascular leakage

The central nervous system (CNS) contains several types of immune cells located in specific anatomic compartments. Macrophages reside at the CNS borders surrounding the brain vessels, in leptomeningeal spaces and the choroid plexus, where they interact with the vasculature and play immunological surveillance and scavenging functions. We investigated the phenotypic changes and role of these macrophages in response to acute ischemic stroke. Given that CD163 expression is a hallmark of perivascular and meningeal macrophages in the rat and human brain, we isolated CD163+ brain macrophages by fluorescence activated cell sorting. We obtained CD163+ cells from control rats and 16 h following transient middle cerebral artery occlusion, after verifying that infiltration of CD163+ peripheral myeloid cells is negligible at this acute time point. Transcriptome analysis of the sorted CD163+ cells identified ischemia-induced upregulation of the hypoxia inducible factor-1 pathway and induction of genes encoding for extracellular matrix components and leukocyte chemoattractants, amongst others. Using a cell depletion strategy, we found that CNS border-associated macrophages participate in granulocyte recruitment, promote the expression of vascular endothelial growth factor (VEGF), increase the permeability of pial and cortical blood vessels, and contribute to neurological dysfunction in the acute phase of ischemia/reperfusion. We detected VEGF expression surrounding blood vessels and in some CD163+ perivascular macrophages in the brain tissue of ischemic stroke patients deceased one day after stroke onset. These findings show ischemia-induced reprogramming of the gene expression profile of CD163+ macrophages that has a rapid impact on leukocyte chemotaxis and blood-brain barrier integrity, and promotes neurological impairment in the acute phase of stroke

Funcionament dels esfigmomanòmetres en l'assistència primària

Es revisa el funcionament de 102 esfigmomanòmetres localitzats en diferents zones d'assistència primària de Barcelona i comarques circumdants. 44 dels aparells eren de mercuri i 58 aneroides. Un 13,63% dels esfigmomanòmetres de mercuri i un 67,24% dels aparells aneroides funcionaven incorrectament considerant funcionament incorrecte un error igual o superior a 4 mm Hg en la lectura respecte un esfigmomanòmetre control, per excés o per defecte. Únicament en una petita fracció dels aparells l'error es podia justificar pel mal estat de les gomes

Protein Expression of the Microglial Marker Tmem119 Decreases in Association With Morphological Changes and Location in a Mouse Model of Traumatic Brain Injury

The activation of microglia and the infiltration of macrophages are hallmarks of neuroinflammation after acute brain injuries, including traumatic brain injury (TBI). The two myeloid populations share many features in the post-injury inflammatory response, thus, being antigenically indistinguishable. Recently Tmem119, a type I transmembrane protein specifically expressed by microglia under physiological conditions, was proposed as a tool to differentiate resident microglia from blood-borne macrophages, not expressing it. However, the validity of Tmem119 as a specific marker of resident microglia in the context of acute brain injury, where microglia are activated and macrophages are recruited, needs validation. Our purpose was to investigate Tmem119 expression and distribution in relation to the morphology of brain myeloid cells present in the injured area after TBI. Mice underwent sham surgery or TBI by controlled cortical impact (CCI). Brains from sham-operated, or TBI mice, were analyzed by in situ hybridization to identify the cells expressing Tmem119, and by Western blot and quantitative immunofluorescence to measure Tmem119 protein levels in the entire brain regions and single cells. The morphology of Iba1+ myeloid cells was analyzed at different times (4 and 7 days after TBI) and several distances from the contused edge in order to associate Tmem119 expression with morphological evolution of active microglia. In situ hybridization indicated an increased Tmem119 RNA along with increased microglial complement C1q activation in the contused area and surrounding regions. On the contrary, the biochemical evaluation showed a drop in Tmem119 protein levels in the same areas. The Tmem119 immunoreactivity decreased in Iba1+ myeloid cells found in the contused cortex at both time points, with the cells showing the hypertrophic ameboid morphology having no Tmem119 expression. The Tmem119 was present on ramifications of resident microglia and its presence was decreased as a consequence of microglial activation in cortical areas close to contusion. Based on the data, we conclude that the decrease of Tmem119 in reactive microglia may depend on the process of microglial activation, which involves the retracting of their branchings to acquire an ameboid shape. The Tmem119 immunoreactivity decreases in reactive microglia to similar levels than the blood-borne macrophages, thus, failing to discriminate the two myeloid populations after TBI.This work was supported by the ERA-NET NEURON, JTC 2016: LEAP, NEURON9-FP-044 from the following national funding institutions: Italian Ministry of Health (Ministero della Salute), Italy; Ministerio de Economía, Industria y Competitividad (PCIN-2017-035) Spain; 01EW1703, Bundesministerium für Bildung und Forschung (BMBF), Germany.Peer reviewe

Risk Factors and Predictive Score for Bacteremic Biliary Tract Infections Due to Enterococcus faecalis and Enterococcus faecium: a Multicenter Cohort Study from the PROBAC Project

Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 [66%] were E. faecium and 25 [34%] E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 [95% CI0.67 to 0.80]. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score ? 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score

Revisiting the epidemiology of bloodstream infections and healthcare-associated episodes: results from a multicentre prospective cohort in Spain (PRO-BAC Study)

PROBAC REIPI/GEIH-SEIMC/SAEI Group.The epidemiology of bloodstream infections (BSIs) is dynamic as it depends on microbiological, host and healthcare system factors. The aim of this study was to update the information regarding the epidemiology of BSIs in Spain considering the type of acquisition. An observational, prospective cohort study in 26 Spanish hospitals from October 2016 through March 2017 including all episodes of BSI in adults was performed. Bivariate analyses stratified by type of acquisition were performed. Multivariate analyses were performed by logistic regression. Overall, 6345 BSI episodes were included; 2510 (39.8%) were community-acquired (CA), 1661 (26.3%) were healthcare-associated (HCA) and 2056 (32.6%) hospital-acquired (HA). The 30-day mortality rates were 11.6%, 19.5% and 22.0%, respectively. The median age of patients was 71 years (interquartile range 60–81 years) and 3656 (58.3%; 95% confidence interval 57.1–59.6%) occurred in males. The proportions according to patient sex varied according to age strata. Escherichia coli (43.8%), Klebsiella spp. (8.9%), Staphylococcus aureus (8.9%) and coagulase-negative staphylococci (7.4%) were the most frequent pathogens. Multivariate analyses confirmed important differences between CA and HCA episodes, but also between HCA and HA episodes, in demographics, underlying conditions and aetiology. In conclusion, we have updated the epidemiological information regarding patients’ profiles, underlying conditions, frequency of acquisition types and aetiological agents of BSI in Spain. HCA is confirmed as a distinct type of acquisition.This work was financed by grants from Plan Nacional de I+D+i 2013–2016, Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades [PI16/01432] and the Spanish Network for Research in Infectious Diseases (REIPI) [RD16/0016/0001; RD16/0016/0008], co‐financed by the European Development Regional Fund ‘A way to achieve Europe’, Operative program Intelligent Growth 2014–2020

Risk Factors and Predictive Score for Bacteremic Biliary Tract Infections Due to Enterococcus faecalis and Enterococcus faecium: a Multicenter Cohort Study from the PROBAC Project

Biliary-tract bloodstream infections (BT-BSI) caused by Enterococcus faecalis and E. faecium are associated with inappropriate empirical treatment and worse outcomes compared to other etiologies. The objective of this study was to investigate the risk factors for enterococcal BT-BSI. Patients with BT-BSI from the PROBAC cohort, including consecutive patients with BSI in 26 Spanish hospitals between October 2016 and March 2017, were selected; episodes caused by E. faecalis or E. faecium and other causes were compared. Independent predictors for enterococci were identified by logistic regression, and a predictive score was developed. Eight hundred fifty episodes of BT-BSI were included; 73 (8.5%) were due to target Enterococcus spp. (48 [66%] were E. faecium and 25 [34%] E. faecalis). By multivariate analysis, the variables independently associated with Enterococcus spp. were (OR; 95% confidence interval): cholangiocarcinoma (4.48;1.32 to 15.25), hospital acquisition (3.58;2.11 to 6.07), use of carbapenems in the previous month (3.35;1.45 to 7.78), biliary prosthesis (2.19;1.24 to 3.90), and moderate or severe chronic kidney disease (1.55;1.07 to 2.26). The AUC of the model was 0.74 [95% CI0.67 to 0.80]. A score was developed, with 7, 6, 5, 4, and 2 points for these variables, respectively, with a negative predictive value of 95% for a score # 6. A model, including cholangiocarcinoma, biliary prosthesis, hospital acquisition, previous carbapenems, and chronic kidney disease showed moderate prediction ability for enterococcal BT-BSI. Although the score will need to be validated, this information may be useful for deciding empirical therapy in biliary tract infections when bacteremia is suspected. IMPORTANCE Biliary tract infections are frequent, and a significant cause of morbidity and mortality. Bacteremia is common in these infections, particularly in the elderly and patients with cancer. Inappropriate empirical treatment has been associated with increased risk of mortality in bacteremic cholangitis, and the probability of receiving inactive empirical treatment is higher in episodes caused by enterococci. This is because many of the antimicrobial agents recommended in guidelines for biliary tract infections lack activity against these organisms. To the best of our knowledge, this is the first study analyzing the predictive factors for enterococcal BT-BSI and deriving a predictive score.8 página