N-glycome profile levels relate to silent brain infarcts in a cohort of hypertensives

Background: Silent brain infarcts (SBIs) are highly prevalent in the aged population and relate to the occurrence of further stroke and dementia. Serum N-glycome levels have been previously associated with aging and they might be related as well to the presence of SBIs and age-related white matter hyperintensities. Methods and Results: We determined the serum N-glycome profile in a cohort study comprising 972 subjects and evaluated the relationship between N-glycome levels and the presence and number of SBIs and with age-related white matter hyperintensities grades, assessed by brain magnetic resonance imaging. Decreasing concentrations of bigalacto core-alpha-1,6-fucosylated biantennary glycan and increasing concentrations of branching alpha-1,3-fucosylated triantennary glycan remained as independent predictors of SBIs (odds ratio 0.4, 95% CI 0.3-0.7 and odds ratio 1.8, 95% CI 1-3.2, respectively), after controlling for the presence of age and classic vascular risk factors. A similar pattern was found to be related to an increasing number of SBIs and white matter hyperintensities grade. Conclusions: N-glycome levels might be potentially useful as biomarkers for the presence of silent cerebrovascular disease

Post-Acquisition Processing Confounds in Brain Volumetric Quantification of White Matter Hyperintensities

BACKGROUND: Disparate research sites using identical or near-identical magnetic resonance imaging (MRI) acquisition techniques often produce results that demonstrate significant variability regarding volumetric quantification of white matter hyperintensities (WMH) in the aging population. The sources of such variability have not previously been fully explored. NEW METHOD: 3D FLAIR sequences from a group of randomly selected aged subjects were analyzed to identify sources-of-variability in post-acquisition processing that can be problematic when comparing WMH volumetric data across disparate sites. The methods developed focused on standardizing post-acquisition protocol processing methods to develop a protocol with less than 0.5% inter-rater variance. RESULTS: A series of experiments using standard MRI acquisition sequences explored post-acquisition sources-of-variability in the quantification of WMH volumetric data. Sources-of-variability included: the choice of image center, software suite and version, thresholding selection, and manual editing procedures (when used). Controlling for the identified sources-of-variability led to a protocol with less than 0.5% variability between independent raters in post-acquisition WMH volumetric quantification. COMPARISON WITH EXISTING METHOD(S): Post-acquisition processing techniques can introduce an average variance approaching 15% in WMH volume quantification despite identical scan acquisitions. Understanding and controlling for such sources-of-variability can reduce post-acquisition quantitative image processing variance to less than 0.5%. DISCUSSION: Considerations of potential sources-of-variability in MRI volume quantification techniques and reduction in such variability is imperative to allow for reliable cross-site and cross-study comparisons

Utilidad de los biomarcadores en el diagnóstico de la enfermedad cerebrovascular silente

Hoy en día, las enfermedades cerebrovasculares tienen un impacto muy importante en la sociedad en países desarrollados, en el nuestro, son una causa muy frecuente de hospitalización, muerte y discapacidad. Además, el envejecimiento de la población conlleva un incremento en la incidencia de estas enfermedades, así como del coste sanitario asociado. Desde hace años, sabemos que los infartos cerebrales pueden darse en ausencia de síntomas acompañantes sugestivos de ictus y en ese caso, hablamos de infartos cerebrales silentes o encubiertos, que en conjunto son cinco veces más frecuentes que el ictus clínico. La mayoría de ellos son infartos lacunares y suceden en el contexto de una enfermedad de pequeño vaso cerebral (EPVC), por lo que coexisten con otros marcadores radiológicos, tales como las lesiones de la sustancia blanca, microsangrados o espacios perivasculares dilatados. El estudio de la enfermedad de pequeño vaso cerebral en estas etapas iniciales o pre-sintomáticas podría contribuir al mejor conocimiento de los mecanismos que conducen a la enfermedad y así facilitar el desarrollo de medidas preventivas eficaces para reducir la incidencia de las mismas y de sus complicaciones (riesgo de ictus futuros y demencia). En esta Tesis Doctoral hemos realizado una revisión bibliográfica que ha puesto de manifiesto que el número de estudios centrados en el uso de biomarcadores para la detección temprana de los signos de EPVC mediante la identificación de las lesiones cerebrales silentes o subclínicas se ha incrementado en los últimos años. Sin embargo, hasta la fecha no se ha conseguido establecer la capacidad diagnostica de los biomarcadores o su papel en la discriminación de las lesiones silentes junto a factores clínicos, que puedan justificar su utilidad clínica. Los estudios previos tienen como limitaciones la heterogeneidad en las definiciones utilizadas de las lesiones de la enfermedad de pequeño vaso cerebral, la falta de replicación de los resultados en cohortes independientes y la inclusión de marcadores candidatos individuales en la mayor parte de casos. Por otra parte, se precisan estudios longitudinales para evaluar la progresión de las lesiones y su relación con los biomarcadores. En esta tesis doctoral se recogen resultados del estudio de biomarcadores en una población hipertensa de entre 50 y 70 años de edad, sin antecedentes de ictus o demencia previos. Se trata de un sustrato adecuado para el estudio del inicio de la enfermedad de pequeño vaso puesto que la hipertensión es un factor de riesgo vascular establecido. Hemos seleccionado biomarcadores novedosos en el campo pero prometedores por su actividad biológica (fosfolipasa A2 ligada a lipoproteínas, NT-proBNP, perfil de N-glicosilación en suero, cociente albumina-creatinina en orina), como candidatos para la predicción de lesiones identificadas en la resonancia magnética cerebral (infartos cerebrales silentes, lesiones de la sustancia blanca y otros marcadores). Hemos analizado las lesiones definidas en la resonancia magnética por separado, y en conjunto, como un escenario más fisiológico de la enfermedad, mediante la aplicación de una escala de enfermedad de pequeño vaso cerebral ya descrita previamente. Se han aplicado criterios estadísticos para valorar la utilidad de los biomarcadores junto con variables clínicas de obtención en la práctica clínica habitual. El estudio de estos y otros biomarcadores, en el contexto de la enfermedad de pequeño vaso cerebral, además de facilitar el diagnóstico, puede proporcionar información de los mecanismos subyacentes en esta etapa pre-clínica, y podrían ser útiles como dianas terapéuticas o para monitorizar la progresión de la enfermedad.Nowadays cerebrovascular diseases have a major social impact; they are a commonly associated with increased rates of hospitalization, morbidity and mortality. Furthermore, it is expected that ageing will increases the incidence of cerebrovascular diseases and their associated healthcare costs. Cerebral infarcts occurring without stroke-like symptoms are known as silent or covert cerebral infarcts; they are five times more common than symptomatic stroke. Most of them are lacunar infarcts and they appear associated with other imaging markers of cerebral small vessel disease, as white matter hyperintensities, microbleeds or dilated perivascular spaces. Research on cerebral small vessel disease pre-clinical or pre-symptomatic stages may potentially improve the knowledge of the leading and involved disease pathways, and the development of prevention approaches aimed to reduce their incidence and associated complications (such as stroke and dementia). In this Thesis, we have performed a bibliographic literature review, and found that the number of studies regarding biomarker usefulness in the early detection of small vessel disease by identification of silent or subclinical cerebral lesions have increased for the last years. However, the use of biomarkers with diagnostic purposes to detect silent brain lesions has not been already established, so clinical their usefulness is still not justified. Previous studies limitations are heterogeneity regarding cerebral small vessel disease lesions definitions, the lack of replication in independent cohorts and the use of individual candidate biomarkers. Also longitudinal studies are needed to evaluate lesions progression and biomarkers associations. In this Thesis we also included biomarker study results, based on a hypertensive stroke and dementia-free population, 50-70 years old. This is a suitable population for the study of the onset of the disease, since hypertension is an established vascular risk factor. Magnetic resonance imaging-defined lesions where analyzed individually, and then combined in a previously described cerebral small vessel disease score being the latter a more physiologic condition. Statistic criteria were applied to evaluate the usefulness of the clinical models including the selected biomarkers, in the clinical practice. Small vessel disease biomarkers study can improve diagnosis of silent brain cerebrovascular lesions and also provide information regarding preclinical stage leading pathways. They can be useful as therapeutic and disease progression monitoring targets

Utilidad de los biomarcadores en el diagnóstico de la enfermedad cerebrovascular silente

Premi Extraordinari de Doctorat concedit pels programes de doctorat de la UAB per curs acadèmic 2017-2018Hoy en día, las enfermedades cerebrovasculares tienen un impacto muy importante en la sociedad en países desarrollados, en el nuestro, son una causa muy frecuente de hospitalización, muerte y discapacidad. Además, el envejecimiento de la población conlleva un incremento en la incidencia de estas enfermedades, así como del coste sanitario asociado. Desde hace años, sabemos que los infartos cerebrales pueden darse en ausencia de síntomas acompañantes sugestivos de ictus y en ese caso, hablamos de infartos cerebrales silentes o encubiertos, que en conjunto son cinco veces más frecuentes que el ictus clínico. La mayoría de ellos son infartos lacunares y suceden en el contexto de una enfermedad de pequeño vaso cerebral (EPVC), por lo que coexisten con otros marcadores radiológicos, tales como las lesiones de la sustancia blanca, microsangrados o espacios perivasculares dilatados. El estudio de la enfermedad de pequeño vaso cerebral en estas etapas iniciales o pre-sintomáticas podría contribuir al mejor conocimiento de los mecanismos que conducen a la enfermedad y así facilitar el desarrollo de medidas preventivas eficaces para reducir la incidencia de las mismas y de sus complicaciones (riesgo de ictus futuros y demencia). En esta Tesis Doctoral hemos realizado una revisión bibliográfica que ha puesto de manifiesto que el número de estudios centrados en el uso de biomarcadores para la detección temprana de los signos de EPVC mediante la identificación de las lesiones cerebrales silentes o subclínicas se ha incrementado en los últimos años. Sin embargo, hasta la fecha no se ha conseguido establecer la capacidad diagnostica de los biomarcadores o su papel en la discriminación de las lesiones silentes junto a factores clínicos, que puedan justificar su utilidad clínica. Los estudios previos tienen como limitaciones la heterogeneidad en las definiciones utilizadas de las lesiones de la enfermedad de pequeño vaso cerebral, la falta de replicación de los resultados en cohortes independientes y la inclusión de marcadores candidatos individuales en la mayor parte de casos. Por otra parte, se precisan estudios longitudinales para evaluar la progresión de las lesiones y su relación con los biomarcadores. En esta tesis doctoral se recogen resultados del estudio de biomarcadores en una población hipertensa de entre 50 y 70 años de edad, sin antecedentes de ictus o demencia previos. Se trata de un sustrato adecuado para el estudio del inicio de la enfermedad de pequeño vaso puesto que la hipertensión es un factor de riesgo vascular establecido. Hemos seleccionado biomarcadores novedosos en el campo pero prometedores por su actividad biológica (fosfolipasa A2 ligada a lipoproteínas, NT-proBNP, perfil de N-glicosilación en suero, cociente albumina-creatinina en orina), como candidatos para la predicción de lesiones identificadas en la resonancia magnética cerebral (infartos cerebrales silentes, lesiones de la sustancia blanca y otros marcadores). Hemos analizado las lesiones definidas en la resonancia magnética por separado, y en conjunto, como un escenario más fisiológico de la enfermedad, mediante la aplicación de una escala de enfermedad de pequeño vaso cerebral ya descrita previamente. Se han aplicado criterios estadísticos para valorar la utilidad de los biomarcadores junto con variables clínicas de obtención en la práctica clínica habitual. El estudio de estos y otros biomarcadores, en el contexto de la enfermedad de pequeño vaso cerebral, además de facilitar el diagnóstico, puede proporcionar información de los mecanismos subyacentes en esta etapa pre-clínica, y podrían ser útiles como dianas terapéuticas o para monitorizar la progresión de la enfermedad.Nowadays cerebrovascular diseases have a major social impact; they are a commonly associated with increased rates of hospitalization, morbidity and mortality. Furthermore, it is expected that ageing will increases the incidence of cerebrovascular diseases and their associated healthcare costs. Cerebral infarcts occurring without stroke-like symptoms are known as silent or covert cerebral infarcts; they are five times more common than symptomatic stroke. Most of them are lacunar infarcts and they appear associated with other imaging markers of cerebral small vessel disease, as white matter hyperintensities, microbleeds or dilated perivascular spaces. Research on cerebral small vessel disease pre-clinical or pre-symptomatic stages may potentially improve the knowledge of the leading and involved disease pathways, and the development of prevention approaches aimed to reduce their incidence and associated complications (such as stroke and dementia). In this Thesis, we have performed a bibliographic literature review, and found that the number of studies regarding biomarker usefulness in the early detection of small vessel disease by identification of silent or subclinical cerebral lesions have increased for the last years. However, the use of biomarkers with diagnostic purposes to detect silent brain lesions has not been already established, so clinical their usefulness is still not justified. Previous studies limitations are heterogeneity regarding cerebral small vessel disease lesions definitions, the lack of replication in independent cohorts and the use of individual candidate biomarkers. Also longitudinal studies are needed to evaluate lesions progression and biomarkers associations. In this Thesis we also included biomarker study results, based on a hypertensive stroke and dementia-free population, 50-70 years old. This is a suitable population for the study of the onset of the disease, since hypertension is an established vascular risk factor. Magnetic resonance imaging-defined lesions where analyzed individually, and then combined in a previously described cerebral small vessel disease score being the latter a more physiologic condition. Statistic criteria were applied to evaluate the usefulness of the clinical models including the selected biomarkers, in the clinical practice. Small vessel disease biomarkers study can improve diagnosis of silent brain cerebrovascular lesions and also provide information regarding preclinical stage leading pathways. They can be useful as therapeutic and disease progression monitoring targets

Ergonómia az építőipar szolgálatában a Tam-Bau Kft.-nél

We conducted a systematic review and individual participant data meta-analysis to explore the role of C-reactive protein (CRP) in early detection or prediction of post-stroke infections. CRP, an acute-phase reactant binds to the phosphocholine expressed on the surface of dead or dying cells and some bacteria, thereby activating complement and promoting phagocytosis by macrophages. We searched PubMed up to May-2015 for studies measuring CRP in stroke and evaluating post-stroke infections. Individual participants' data were merged into a single database. CRP levels were standardized and divided into quartiles. Factors independently associated with post-stroke infections were determined by logistic regression analysis and the additional predictive value of CRP was assessed by comparing areas under receiver operating characteristic curves and integrated discrimination improvement index. Data from seven studies including 699 patients were obtained. Standardized CRP levels were higher in patients with post-stroke infections beyond 24 h. Standardized CRP levels in the fourth quartile were independently associated with infection in two different logistic regression models, model 1 [stroke severity and dysphagia, odds ratio = 9.70 (3.10-30.41)] and model 2 [age, sex, and stroke severity, odds ratio = 3.21 (1.93-5.32)]. Addition of CRP improved discrimination in both models [integrated discrimination improvement = 9.83% (0.89-18.77) and 5.31% (2.83-7.79), respectively], but accuracy was only improved for model 1 (area under the curve 0.806-0.874, p = 0.036). In this study, CRP was independently associated with development of post-stroke infections, with the optimal time-window for measurement at 24-48 h. However, its additional predictive value is moderate over clinical information. Combination with other biomarkers in a panel seems a promising strategy for future studies

Supplementary Material for: Microalbuminuria and the Combination of MRI Markers of Cerebral Small Vessel Disease

<b><i>Background:</i></b> Kidney function has been related to the presence of individual markers of cerebral small vessel disease (CSVD), as lacunes, white matter hyperintensities (WMH) or microbleeds. We aimed at studying the relationship of kidney dysfunction with the combination of several markers of CSVD. <b><i>Methods:</i></b> Subjects are those included in the ISSYS cohort (Investigating Silent Strokes in hypertensives: a magnetic resonance imaging study). A scale ranging from 0 to 4 points was applied based on the presence (one point each) of lacunes, deep microbleeds, moderate to extensive basal ganglia enlarged perivascular spaces (EPVS), and periventricular or deep WMH. We determined the creatinine-based glomerular filtration rate and the urinary albumin-to-creatinine ratio (UACR) as markers of kidney function and studied their association with the scale of CSVD in univariate and ordinal logistic regression analyses. <b><i>Results:</i></b> Among the 975 patients included, 28.2% presented one or more CSVD markers, being the most prevalent marker (either alone or in combination) basal ganglia EPVS. The UACR was elevated at increasing the scores of the CSVD scale and remained as independent predictor of the combination of markers (common OR per natural log unit increase in UACR: 1.23, 1.07-1.41) after controlling per age, gender, cardiovascular risk, antihypertensive treatment and hypertension duration. In contrast, no associations were found between the CSVD scores and the creatinine-based estimated glomerular filtration rate. <b><i>Conclusions:</i></b> A significant proportion of stroke-free hypertensives present at least one imaging marker of CSVD. UACR but not creatinine-based glomerular filtration rate is associated with the combination of markers of CSVD