Papel de la reducción de histonas en la protección de los telómeros durante la pre-senescencia

Los telómeros son estructuras nucleoproteícas cuya función principal es evitar que los extremos de los cromosomas sean reconocidos como roturas en el ADN y sean procesados por las maquinarias de checkpoints y reparación, dando lugar a paradas en el ciclo celular y reordenamientos genómicos. Debido a la replicación semiconservativa de los telómeros, estos se acortan tras cada ciclo de replicación. Para evitarlo, las células expresan una transcriptasa reversa, la telomerasa, que extiende las repeticiones teloméricas, y mantiene la longitud de los telómeros. A pesar de que los telómeros evitan que lo extremos sean considerados como DSBs, muchas de las proteínas implicadas en su homeostasis son proteínas de las propias maquinarias de checkpoints y reparación. Por ello, las células regulan la unión y actividad de dichas proteínas, que son esenciales para el mantenimiento de los telómeros y evitan la activación involuntaria de la respuesta de daños en el ADN. Un ejemplo son las proteínas Mec1 y Tel1, homólogos en Saccharomyces cerevisiae de los genes supresores de tumores ATR y ATM, respectivamente. Mec1 y Tel1 son las principales quinasas de los checkpoint de daños en el ADN, con papeles específicos y redundantes en muchos procesos relacionados con la integridad genómica, como la señalización de DSBs. Además poseen funciones específicas en los telómeros, ya que Tel1 es fundamental en el reclutamiento de la telomerasa a telómeros cortos, apoyada por Mec1. La expresión de la telomerasa es reprimida en muchos tejidos de organismos multicelulares. Esto produce a una erosión continua de los telómeros que conduce a un arresto irreversible del ciclo celular, conocido como senescencia replicativa y considerado como un mecanismo de supresión de tumores. Específicamente, Mec1 transduce la señal que activa la senescencia en células carentes de telomerasa cuando los telómeros alcanzan una longitud crítica. Sin embargo, una entrada prematura en senescencia puede afectar a la homeostasis de los tejidos, por lo que las células están dotadas con mecanismos para mantener su estado proliferativo con telómeros cortos. En esta respuesta destacan los genes ATM y ATR, los cuales previenen la formación de fusiones teloméricas durante la pre-senescencia, evitando la subsiguiente inestabilidad genética asociada a ciclos de rotura-fusión-puente. A pesar de la importancia de entender cómo la inestabilidad genética se acumula en ausencia de estos dos genes, los mecanismos mediante los cuales ATR y ATM llevan a cabo este papel de protección telomérica apenas se conocen. En esta tesis demostramos que las T-TFs en células mec1Δ tel1Δ pueden ser suprimidas induciendo una reducción en los niveles celulares de histonas. Esta supresión, junto con el hecho de que Mec1 es necesario para reducir los niveles de histonas en células pre-senescentes tlc1Δ, las cuales tienen telómeros protegidos, sugiere que la acumulación de T-TFs en células mec1Δ tel1Δ es debida en parte a su incapacidad de inducir una reducción de histonas. Además, vemos que la ausencia de Mec1 y Tel1 aumenta considerablemente la reparación de DSBs por NHEJ, lo que también podría contribuir a la alta frecuencia de T-TFs en las células mec1Δ tel1Δ. Sin embargo, la reducción de histonas no previene las fusiones teloméricas inhibiendo NHEJ, que de hecho también aumenta al reducir los niveles de histonas. Por el contrario, la reducción de histonas previene las fusiones teloméricas facilitando el procesamiento recombinacional de los telómeros desprotegidos a través de un mecanismo independiente de Rad51. Este mecanismo de recombinación es diferente de los principales mecanismos de HR que facilitan la elongación de telómeros críticamente cortos durante la pre-senescencia o que amplifican los elementos subteloméricos Y´ en las células supervivientes, los cuales no requieren niveles de histonas reducidos y son altamente dependientes de Rad51

Construcción de una metagenoteca a partir de muestras de una depuradora de aguas de hospital para la obtención de funciones de interés ambiental y biomédico.

Motivación: La demanda de medicamentos, especialmente de los antibióticos, ha ido en aumento en los últimos tiempos. A pesar de que muchos de ellos son biodegradables, a menudo se encuentran como contaminantes de las aguas residuales tratadas, lo cual supone un riesgo ecológico y sanitario ya que es posible la aparición de microorganismos resistentes limitando su efectividad. De aquí surge la necesidad de analizar qué microorganismos pueden ser resistentes, y en concreto qué genes les confieren dicha resistencia, para lo cual se propone construir una metagenoteca a partir de aguas residuales de una depuradora de hospital. En ella la concentración de antibióticos es mayor y existen antibióticos tanto de uso frecuente como exclusivos de hospitales.Métodos: Para la construcción de la metagenoteca se siguió el protocolo estándar, “CopyControlTM Fosmid Library Production Kit protocol (Epicentre)”, con algunas modificaciones [1]. En primer lugar se realizó la extracción del ADN de las muestras de la depuradora, para lo cual se realizaron diversas pruebas utilizando kits comerciales de extracción así como otros métodos descritos [2,3]. Tras la extracción se comprobó que el ADN purificado no se degradara, se seleccionó el tamaño adecuado, determinado por la capacidad de empaquetar del fago lambda (≈40kb), y se repararon los extremos para su clonación. Por otra parte, el fósmido que se empleó para la construcción de la metagenoteca, se digirió con PmlI y desfosforiló con SAP. Para que la metagenoteca sea representativa, han de conseguirse concentraciones muy altas tanto del vector como del inserto. Finalmente, el ADN ligado se empaquetó en extractos del fago lambda que se emplean para infectar células EPI300-T1R. Estas bacterias transformadas con el vector, constituyen la metagenoteca.Resultados: Se han buscado bacterias resistentes a diferentes concentraciones de los antibióticos colistina y ceftriaxona. A las concentraciones probadas por el momento, sólo se ha encontrado resistencia a ceftriaxona. Actualmente se sigue trabajando para construir una nueva metagenoteca y mejorar todo el proceso.Conclusiones: Se han obtenido bacterias resistentes a ceftriaxona en la primera metagenoteca construida, a pesar del bajo número de clones de esta. Esto pone de manifiesto la robustez del sistema para detectar actividades génicas incluso teniendo una baja representación en la metagenoteca de los organismos con dicha actividad presentes en el medio

Crosstalk between chromatin structure, cohesin activity and transcription

Background: A complex interplay between chromatin and topological machineries is critical for genome architec‑ ture and function. However, little is known about these reciprocal interactions, even for cohesin, despite its multiple roles in DNA metabolism. Results: We have used genome‑wide analyses to address how cohesins and chromatin structure impact each other in yeast. Cohesin inactivation in scc1‑73 mutants during the S and G2 phases causes specific changes in chromatin structure that preferentially take place at promoters; these changes include a significant increase in the occupancy of the − 1 and + 1 nucleosomes. In addition, cohesins play a major role in transcription regulation that is associated with specific promoter chromatin architecture. In scc1‑73 cells, downregulated genes are enriched in promoters with short or no nucleosome‑free region (NFR) and a fragile “nucleosome − 1/RSC complex” particle. These results, together with a preferential increase in the occupancy of nucleosome − 1 of these genes, suggest that cohesins promote transcription activation by helping RSC to form the NFR. In sharp contrast, the scc1‑73 upregulated genes are enriched in promoters with an “open” chromatin structure and are mostly at cohesin‑enriched regions, suggesting that a local accumulation of cohesins might help to inhibit transcription. On the other hand, a dramatic loss of chromatin integrity by histone depletion during DNA replication has a moderate effect on the accumulation and distribution of cohesin peaks along the genome. Conclusions: Our analyses of the interplay between chromatin integrity and cohesin activity suggest that cohesins play a major role in transcription regulation, which is associated with specific chromatin architecture and cohesin‑ mediated nucleosome alterations of the regulated promoters. In contrast, chromatin integrity plays only a minor role in the binding and distribution of cohesins.Spanish Ministry of Economy and Competitivenes BFU2012-38171, BFU2015-63698-PAndalusian Government P12-CTS-227

Effectiveness of a strategy that uses educational games to implement clinical practice guidelines among Spanish residents of family and community medicine (e-EDUCAGUIA project):A clinical trial by clusters

This study was funded by the Fondo de Investigaciones Sanitarias FIS Grant Number PI11/0477 ISCIII.-REDISSEC Proyecto RD12/0001/0012 AND FEDER Funding.Background: Clinical practice guidelines (CPGs) have been developed with the aim of helping health professionals, patients, and caregivers make decisions about their health care, using the best available evidence. In many cases, incorporation of these recommendations into clinical practice also implies a need for changes in routine clinical practice. Using educational games as a strategy for implementing recommendations among health professionals has been demonstrated to be effective in some studies; however, evidence is still scarce. The primary objective of this study is to assess the effectiveness of a teaching strategy for the implementation of CPGs using educational games (e-learning EDUCAGUIA) to improve knowledge and skills related to clinical decision-making by residents in family medicine. The primary objective will be evaluated at 1 and 6months after the intervention. The secondary objectives are to identify barriers and facilitators for the use of guidelines by residents of family medicine and to describe the educational strategies used by Spanish teaching units of family and community medicine to encourage implementation of CPGs. Methods/design: We propose a multicenter clinical trial with randomized allocation by clusters of family and community medicine teaching units in Spain. The sample size will be 394 residents (197 in each group), with the teaching units as the randomization unit and the residents comprising the analysis unit. For the intervention, both groups will receive an initial 1-h session on clinical practice guideline use and the usual dissemination strategy by e-mail. The intervention group (e-learning EDUCAGUIA) strategy will consist of educational games with hypothetical clinical scenarios in a virtual environment. The primary outcome will be the score obtained by the residents on evaluation questionnaires for each clinical practice guideline. Other included variables will be the sociodemographic and training variables of the residents and the teaching unit characteristics. The statistical analysis will consist of a descriptive analysis of variables and a baseline comparison of both groups. For the primary outcome analysis, an average score comparison of hypothetical scenario questionnaires between the EDUCAGUIA intervention group and the control group will be performed at 1 and 6months post-intervention, using 95% confidence intervals. A linear multilevel regression will be used to adjust the model. Discussion: The identification of effective teaching strategies will facilitate the incorporation of available knowledge into clinical practice that could eventually improve patient outcomes. The inclusion of information technologies as teaching tools permits greater learning autonomy and allows deeper instructor participation in the monitoring and supervision of residents. The long-term impact of this strategy is unknown; however, because it is aimed at professionals undergoing training and it addresses prevalent health problems, a small effect can be of great relevance. Trial registration: ClinicalTrials.gov: NCT02210442.Publisher PDFPeer reviewe

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Healthcare workers hospitalized due to COVID-19 have no higher risk of death than general population. Data from the Spanish SEMI-COVID-19 Registry

Aim To determine whether healthcare workers (HCW) hospitalized in Spain due to COVID-19 have a worse prognosis than non-healthcare workers (NHCW). Methods Observational cohort study based on the SEMI-COVID-19 Registry, a nationwide registry that collects sociodemographic, clinical, laboratory, and treatment data on patients hospitalised with COVID-19 in Spain. Patients aged 20-65 years were selected. A multivariate logistic regression model was performed to identify factors associated with mortality. Results As of 22 May 2020, 4393 patients were included, of whom 419 (9.5%) were HCW. Median (interquartile range) age of HCW was 52 (15) years and 62.4% were women. Prevalence of comorbidities and severe radiological findings upon admission were less frequent in HCW. There were no difference in need of respiratory support and admission to intensive care unit, but occurrence of sepsis and in-hospital mortality was lower in HCW (1.7% vs. 3.9%; p = 0.024 and 0.7% vs. 4.8%; p<0.001 respectively). Age, male sex and comorbidity, were independently associated with higher in-hospital mortality and healthcare working with lower mortality (OR 0.211, 95%CI 0.067-0.667, p = 0.008). 30-days survival was higher in HCW (0.968 vs. 0.851 p<0.001). Conclusions Hospitalized COVID-19 HCW had fewer comorbidities and a better prognosis than NHCW. Our results suggest that professional exposure to COVID-19 in HCW does not carry more clinical severity nor mortality

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries