Proyectos
- Octubre 2017 - Septiembre 2018
Adjudicado
Development of in ovo model for treating the hypoxia-induced fetal growth restriction in the chicken embryo
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]As a scientist in Chile, I have been focused on understanding the mechanisms underlying fetal vascular dysfunction associated with altered fetal growth with a special interest in impaired fetal growth and epigenetic regulation. Fetal growth restriction (FGR), commonly defined by a weight below the 10th percentile is associated with increased perinatal morbidity and mortality with an incidence of 3 to 10% of all live births1, 2. Therefore, FGR remains at the forefront of basic science and clinical investigation, as it poses a significant problem on every nations wealth and health. Adverse conditions in complicated pregnancy known to induce FGR include reductions in fetal oxygenation or chronic fetal hypoxia3. Several studies in humans have established that high altitude pregnancy reduces fetal growth 4-6. Further, several studies in mammalian animal models of hypoxic pregnancy have also reported a significant effect in slowing fetal growth7. However, since most high altitude populations are also impoverished with a high prevalence of maternal undernutrition and since hypoxic exposure of mammalian animals during pregnancy can reduce maternal food intake7, the partial contributions of fetal under-nutrition versus fetal under-oxygenation in promoting FGR remain uncertain.
The Giussani group at the University of Cambridge have combined the chick embryo model with hypoxic incubation to isolate the direct effects of chronic fetal hypoxia in promoting FGR. This group has shown that incubation at high altitude of fertilized eggs laid by sea level hens leads to FGR. Conversely, incubation at sea level of fertilized eggs laid by high altitude hens that normally show FGR completely recovered fetal growth. Importantly, incubation at high altitude of fertilized eggs laid by sea level with oxygen supplementation also prevented FGR8. Recent studies by the Cambridge group have also reported that isobaric rather than hypobaric chronic fetal hypoxia also leads to FGR in the chick embryo9. Further, they have reported that FGR as a result of isolated chronic fetal hypoxia is associated with significant oxidative stress and endothelial dysfunction in fetal peripheral circulations. Treatment of chick embryos during hypoxic incubation with the antioxidant melatonin rescued the endothelial dysfunction in peripheral circulations by the end of the incubation period. The mechanisms involved included reduced oxidative stress, enhanced antioxidant capacity, restored vascular endothelial growth factor expression and increased NO bioavailability9. Combined, therefore, studies by the Cambridge group have isolated a direct effect of hypoxia in promoting FGR and fetal endothelial dysfunction independent of effects at the level of the placenta or the mother and suggest that antioxidant therapy may also have a direct protective effect on the fetus.
These findings are of particular interest to me because my research group in Chile has recently established a guinea pig experimental model of FGR. This is by progressive bilateral occlusion of the uterine arteries during the second half of gestation that gradually increases placental vascular resistance10, 11. Using this guinea pig model, we have recently shown that FGR induces epigenetic programming of eNOS expression in the fetal endothelium, which is prevented by a maternal treatment with N-acetylcysteine11. However, whether the effects of increased placental vascular resistance on the fetal epigenetic programming of eNOS expression is due to fetal under-nutrition versus fetal under-oxygenation in this model of FGR again remains uncertain. Therefore, the aim of my research proposal is to use the Cambridge chick embryo model of FGR as a result of hypoxic incubation to isolate the direct effects of chronic fetal hypoxia on epigenetic regulation promoting fetal vascular dysfunction. This would be the first step to enable better identification of potential targets for clinical intervention designed to protect the developing fetal circulation in pregnancy complicated by FGR and chronic fetal hypoxia.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Septiembre 2017 - Diciembre 2020
En Ejecución
Desarrollo de instrumentos culturalmente específicos sobre estigma hacia la enfermedad mental y su relación con funcionalidad global en América Latina (Development of Specific Cultural Elements to Evaluate Stigmas towards Mental Health and its Relationshi
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]*Research Question(s)/Hypothesis (es)
Aim 1: To examine the degree to which 'what matters most' differs in Chile and Argentina from other cultures in which this has been studied by qualitatively assessing key culture-specific domains of stigma. We propose that thematic analyses will reveal differences in how what matters most shapes stigma in these contexts.
Aim 2: To operationalize items to create culture-specific stigma modules for two widely used stigma measures. We will operationalize culture-specific variation in stigma via a pool of initial survey items and use pilot testing with local experts and respondents to create final culture specific stigma modules for each scale.
Aim 3: To validate 2 new measures of culture-specific and universal aspects of stigma by administering these measures to 150 participants in Chile. We propose that our culture-specific modules will aid prediction of construct validity scales, with different domains of global functioning as key outcomes.
*Study Implementation
We are carrying out our fieldwork to develop culturally specific assessments of stigma in two sites: the city of Cordoba in Argentina and in the Santiago Metropolitan area and the adjacent Region of OHiggins in Chile.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Agosto 2017 - Diciembre 2018
Ejecutado
Atención Primaria y Salud Mental: Estudio multicéntrico de Redes de Servicios de Salud Mental en Perú, Argentina, Bolivia, Ecuador y Chile (EVAREDCOM)
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]La Becas Iberoamericana, Jóvenes Profesores e Investigadores de Santander Universidades permitió iniciar y desarrollar una línea de investigación que aun mantengo vinculada a la evaluación de servicios de salud mental comunitaria.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Julio 2017 - Junio 2018
Adjudicado
Time-course modeling of the endothelial epigenetic programming by fetal growth restriction: role of miRNAs miR-21 & miR-126.
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""][/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Julio 2017 - Junio 2018
Adjudicado
Time-course modeling of the endothelial epigenetic programming by fetal growth restriction: role of miRNAs miR-21 & miR-126.
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""][/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Abril 2017 - Enero 2018
Ejecutado
Desarrollo y evaluación de un modelo de intervención basado en tecnologías de la información y de la comunicación (TICs) para reducir el riesgo de suicidio adolescente en establecimientos educacionales de la RM y la VI Región.
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Objetivo General del proyecto fue desarrollar y evaluar un modelo de intervención basado en tecnologías de la información y comunicación para reducir riesgo suicida y fortalecer factores protectores de la salud mental en adolescentes de establecimientos educacionales de la RM y VI Región.
El producto central es una plataforma web, con aplicaciones móviles asociadas, que incluye un componente psicoeducativo y uno interactivo que estará constituido por recursos que fomentan el apoyo entre pares (adolescentes) y la generación de estrategias para afrontar problemas afectivos y sociales.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Abril 2017 - Marzo 2021
Adjudicado
Fondecyt Regular 1170608. Biomechanical behavior of arteries from chronic hypoxic animals: experiments, modelling, numerical simulation and validation
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Appropriate arterial function and structure are vital for a proper cardiovascular performance and therefore fundamental for a healthy life. Arterial function depends on cellular and molecular mechanisms but as well on the structural features. In fact, it has been shown that structural and biomechanical properties of vessels are very much related to several cardiovascular pathologies, such as systemic and pulmonary hypertension. Chronic lack of oxygen (hypoxia), may determine an impairment of the cardiovascular function, potentially deriving in pulmonary/systemic hypertension and cardiac failure. This is particularly relevant in human populations exposed to high altitude (above 2500m), either in chronic continuous (permanent inhabitants) or chronic intermittent (shifts of high altitude workers, such as miners, custom agents astronomers; and mountaineers) fashions. Most of the studies about vascular effects of chronic hypoxia have focused on function and molecular mechanisms involved in the pathophysiological responses. However, few is known about the biomechanical responses of systemic, pulmonary and cerebral arteries in these conditions, particularly in the chronic exposure to hypoxia as it happens in high-altitude population and in several diseases in lowlanders. The main goal of this project is to determine the vascular biomechanical characteristics of a representative rat paradigm of living under hypoxia and, in addition, establish the modelling, numerical simulation and experimental validation of the biomechanical responses of arterial vessels.
Specifically, three different types of vessels (aorta, carotid and femoral), at different age (neonates, juveniles and adults)
will be analyzed, either under normoxic, chronic permanent hypoxic or chronic intermittent hypoxic conditions.
Small rodents have been extensively used as a paradigm of cardiovascular and vascular function, allowing massive
steps in the knowledge of mechanisms involved in cardiovascular pathologies. Using a rat model, we will deeply analyze
the biomechanical properties of the vasculature of animals exposed to chronic hypoxia (permanent or intermittent) in a
hypobaric chamber, adding substantial data for the comprehension of the vascular biomechanical behaviour under these
conditions.
The need for a better understanding of the biomechanical response of arteries leads to the development of constitutive
models that may define realistic and reliable stress-strain relationships. In this project, several constitutive models aimed
at describing the biomechanical behaviour of soft tissues will be assessed. The specific aspects to be taken into account
of the vessels biomechanical characterisation are: incompressibility of the tissue, presence of large deformations, isotropic and anisotropic material behaviours, residual stresses, rate dependent (i.e., viscous) effects, damage and active response. The material characterisation of the biomechanical behaviour of rat arteries will be performed via in-vitro biaxial and myograph tensile tests and ring opening test, considering standard, cyclic and relaxation loading conditions. From these experiments, the material characterisation will also involve the derivation of the material parameters. Specifically, we will address the development of algorithms for the treatment of non-linearities in the fitting procedure and sensitivity analysis to determine the consistency of the parameters found with this methodology. The analysis will also include comparison between the numerical predictions of the different constitutive models in their application to experimental data to be measured in this project.
The analysis of the response of pressurised straight arterial vessels will be additionally carried out. Importantly, this
test mimics the in-vivo physiological conditions of the arterial vessel. Aside from the internal pressure, axial stretching is
usually considered. As a non-uniform biaxial stress state is commonly developed in this test, this fact extends the validity of the material characterisation. The material response will be described via the constitutive models previously characterised. Due to the complex stress and strain patterns developed in this problem, numerical simulations defined in the context of the finite element method will be performed. The obtained numerical results will be validated with the corresponding experimental measurements. Moreover, we expect to characterise the biomechanical properties of different vascular beds, representatives of systemic, pulmonary and cerebral circulations. We shall also describe the effects of chronic hypoxia on these properties. Furthermore, we will perform histological analyses to assess the ultrastructure and the wall components of the intima, media and adventitia layers and relate them with the biomechanical findings.
The outcomes of this project will enhance the knowledge necessary to integrate the functional, structural and
biomechanical properties of vascular tissues. Clearly, our data will provide useful information not only for vascular pathophysiology understanding, but also for optimization of medical diagnosis, prognosis and potential therapeutic approaches to the related pathologies[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Abril 2017 - Marzo 2021
Adjudicado
Fondecyt Regular 1171406. Fetal programming of inflammatory responses and body fat by maternal obesity: Role of DHA in the modulation of epigenetic markers of obesity and metabolic disease
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Overweight and Obesity are worldwide epidemic conditions defined as a body mass index (BMI) ≥ 25 and ≥30, respectively, characterized by an excessive accumulation of adipose tissue in the body that impairs both physical and psychosocial health and well-being [1]. Notably, according to the Chilean National Health Survey (ENS 2009-2010), 60% of woman in reproductive age (i.e. 15 and 44 years) are overweight or obese [2] with detrimental consequences on women as well as offspring health at long term. Epidemiological evidences have recognized pre-gestational obesity and, in a lesser degree, excessive gestational weight gain (GWG) as independent risk factors in the development of maternal complications and adverse perinatal outcomes [3]. This includes congenital malformations, perinatal death, large for gestational age babies (LGA, >p 90th), macrosomia (> 4 Kg at birth), birth dystocia, neonatal hypoglycemia, and others [4]. This evidences leaded the Institute of Medicine of the National Academy of Sciences of the United States (IOM) to provide guidelines for maternal weight gain in 1990, updated in 2009 [5] in order to improve maternal and perinatal outcomes. Conversely, a large number of evidence has shown that a deficient maternal nutrition during pregnancy affects the early in utero development, inducing adaptations/responses in the fetus and neonate which have been associated to increased risk of diseases in adulthood [6]. This concept, known as "Developmental Origins of Health and Disease (DOHaD, referred also as intrauterine programming in this proposal) which was coined by Professor David Barker, who reported the association of low birth weight and the risk of T2DM and cardiovascular disease. Notably not only in utero under-nutrition (e.g. intrauterine growth restriction) but also over-nutrition (e.g. macrosomia, LGA) increase the cardiometabolic risk in the offspring [7-9]. Whilst the effect of maternal undernutrition on the risk of disease in the offspring has been extensively addressed, new efforts are required to clarify how increased maternal obesity and body fat previous and during pregnancy impinge an increased cardiometabolic risk in the progeny.
In this context, in addition to perinatal complications associated with maternal obesity (MO), there is evidence of persistent adverse effects in the offspring throughout their lifespan. In fact, excessive maternal gestational weight gain is associated with a 2-fold increase in cardiometabolic risk in the offspring, which is evidenced since early infancy [10]. Notably, this effect is substantially higher (~5-fold increase) in offspring from women that initiate their pregnancy with obesity [11, 12]. This is relevant due to the high rate of childhood overweight/obesity in Chile (32.2% of the children ≤ 6 yo are overweight/obese, according to the ENS 2010), which is a strong predictor of later cardiometabolic complications in adulthood [13]. The effect of MO on susceptibility to obesity in the offspring appears to be independent of the presence of gestational diabetes (GDM) [14, 15]. This could have its origin during fetal development since it has been described that newborn whose mothers are obese, with normal glycaemia during gestation, present an increased adiposity versus lean mass compared to control pregnancies [16]. In this respect, it is noteworthy that the size of abdominal adipose tissue and hepatocellular lipid content in neonates strongly correlates with maternal BMI [17-19]. This has been also observed in offspring from pregnant obese non-human primates and mice, which exhibit increased accumulation of hepatic triglycerides and ceramides even before birth [17-19]. Furthermore, MO also relates with metabolic disturbances in the newborn, such as a reduced insulin sensitivity and altered inflammatory markers [20]. Altogether these data suggest that postnatal obesity could be programmed by MO during fetal development, however the mechanisms underlying the intrauterine programming of obesity are currently unknown. In this context inflammation, a mechanism exacerbated in pregnancies with MO, represents a potential pathway participating in this process.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Abril 2017 - Marzo 2021
Adjudicado
Fondecyt Regular 1170608. Biomechanical behavior of arteries from chronic hypoxic animals: experiments, modelling, numerical simulation and validation
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Appropriate arterial function and structure are vital for a proper cardiovascular performance and therefore fundamental for a healthy life. Arterial function depends on cellular and molecular mechanisms but as well on the structural features. In fact, it has been shown that structural and biomechanical properties of vessels are very much related to several cardiovascular pathologies, such as systemic and pulmonary hypertension. Chronic lack of oxygen (hypoxia), may determine an impairment of the cardiovascular function, potentially deriving in pulmonary/systemic hypertension and cardiac failure. This is particularly relevant in human populations exposed to high altitude (above 2500m), either in chronic continuous (permanent inhabitants) or chronic intermittent (shifts of high altitude workers, such as miners, custom agents astronomers; and mountaineers) fashions. Most of the studies about vascular effects of chronic hypoxia have focused on function and molecular mechanisms involved in the pathophysiological responses. However, few is known about the biomechanical responses of systemic, pulmonary and cerebral arteries in these conditions, particularly in the chronic exposure to hypoxia as it happens in high-altitude population and in several diseases in lowlanders. The main goal of this project is to determine the vascular biomechanical characteristics of a representative rat paradigm of living under hypoxia and, in addition, establish the modelling, numerical simulation and experimental validation of the biomechanical responses of arterial vessels.
Specifically, three different types of vessels (aorta, carotid and femoral), at different age (neonates, juveniles and adults)
will be analyzed, either under normoxic, chronic permanent hypoxic or chronic intermittent hypoxic conditions.
Small rodents have been extensively used as a paradigm of cardiovascular and vascular function, allowing massive
steps in the knowledge of mechanisms involved in cardiovascular pathologies. Using a rat model, we will deeply analyze
the biomechanical properties of the vasculature of animals exposed to chronic hypoxia (permanent or intermittent) in a
hypobaric chamber, adding substantial data for the comprehension of the vascular biomechanical behaviour under these
conditions.
The need for a better understanding of the biomechanical response of arteries leads to the development of constitutive
models that may define realistic and reliable stress-strain relationships. In this project, several constitutive models aimed
at describing the biomechanical behaviour of soft tissues will be assessed. The specific aspects to be taken into account
of the vessels biomechanical characterisation are: incompressibility of the tissue, presence of large deformations, isotropic and anisotropic material behaviours, residual stresses, rate dependent (i.e., viscous) effects, damage and active response. The material characterisation of the biomechanical behaviour of rat arteries will be performed via in-vitro biaxial and myograph tensile tests and ring opening test, considering standard, cyclic and relaxation loading conditions. From these experiments, the material characterisation will also involve the derivation of the material parameters. Specifically, we will address the development of algorithms for the treatment of non-linearities in the fitting procedure and sensitivity analysis to determine the consistency of the parameters found with this methodology. The analysis will also include comparison between the numerical predictions of the different constitutive models in their application to experimental data to be measured in this project.
The analysis of the response of pressurised straight arterial vessels will be additionally carried out. Importantly, this
test mimics the in-vivo physiological conditions of the arterial vessel. Aside from the internal pressure, axial stretching is
usually considered. As a non-uniform biaxial stress state is commonly developed in this test, this fact extends the validity of the material characterisation. The material response will be described via the constitutive models previously characterised. Due to the complex stress and strain patterns developed in this problem, numerical simulations defined in the context of the finite element method will be performed. The obtained numerical results will be validated with the corresponding experimental measurements. Moreover, we expect to characterise the biomechanical properties of different vascular beds, representatives of systemic, pulmonary and cerebral circulations. We shall also describe the effects of chronic hypoxia on these properties. Furthermore, we will perform histological analyses to assess the ultrastructure and the wall components of the intima, media and adventitia layers and relate them with the biomechanical findings.
The outcomes of this project will enhance the knowledge necessary to integrate the functional, structural and
biomechanical properties of vascular tissues. Clearly, our data will provide useful information not only for vascular pathophysiology understanding, but also for optimization of medical diagnosis, prognosis and potential therapeutic approaches to the related pathologies[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
Co-Investigador/a
- Abril 2017 - Marzo 2021
Adjudicado
Fondecyt Regular 1171406. Fetal programming of inflammatory responses and body fat by maternal obesity: Role of DHA in the modulation of epigenetic markers of obesity and metabolic disease
[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Overweight and Obesity are worldwide epidemic conditions defined as a body mass index (BMI) ≥ 25 and ≥30, respectively, characterized by an excessive accumulation of adipose tissue in the body that impairs both physical and psychosocial health and well-being [1]. Notably, according to the Chilean National Health Survey (ENS 2009-2010), 60% of woman in reproductive age (i.e. 15 and 44 years) are overweight or obese [2] with detrimental consequences on women as well as offspring health at long term. Epidemiological evidences have recognized pre-gestational obesity and, in a lesser degree, excessive gestational weight gain (GWG) as independent risk factors in the development of maternal complications and adverse perinatal outcomes [3]. This includes congenital malformations, perinatal death, large for gestational age babies (LGA, >p 90th), macrosomia (> 4 Kg at birth), birth dystocia, neonatal hypoglycemia, and others [4]. This evidences leaded the Institute of Medicine of the National Academy of Sciences of the United States (IOM) to provide guidelines for maternal weight gain in 1990, updated in 2009 [5] in order to improve maternal and perinatal outcomes. Conversely, a large number of evidence has shown that a deficient maternal nutrition during pregnancy affects the early in utero development, inducing adaptations/responses in the fetus and neonate which have been associated to increased risk of diseases in adulthood [6]. This concept, known as "Developmental Origins of Health and Disease (DOHaD, referred also as intrauterine programming in this proposal) which was coined by Professor David Barker, who reported the association of low birth weight and the risk of T2DM and cardiovascular disease. Notably not only in utero under-nutrition (e.g. intrauterine growth restriction) but also over-nutrition (e.g. macrosomia, LGA) increase the cardiometabolic risk in the offspring [7-9]. Whilst the effect of maternal undernutrition on the risk of disease in the offspring has been extensively addressed, new efforts are required to clarify how increased maternal obesity and body fat previous and during pregnancy impinge an increased cardiometabolic risk in the progeny.
In this context, in addition to perinatal complications associated with maternal obesity (MO), there is evidence of persistent adverse effects in the offspring throughout their lifespan. In fact, excessive maternal gestational weight gain is associated with a 2-fold increase in cardiometabolic risk in the offspring, which is evidenced since early infancy [10]. Notably, this effect is substantially higher (~5-fold increase) in offspring from women that initiate their pregnancy with obesity [11, 12]. This is relevant due to the high rate of childhood overweight/obesity in Chile (32.2% of the children ≤ 6 yo are overweight/obese, according to the ENS 2010), which is a strong predictor of later cardiometabolic complications in adulthood [13]. The effect of MO on susceptibility to obesity in the offspring appears to be independent of the presence of gestational diabetes (GDM) [14, 15]. This could have its origin during fetal development since it has been described that newborn whose mothers are obese, with normal glycaemia during gestation, present an increased adiposity versus lean mass compared to control pregnancies [16]. In this respect, it is noteworthy that the size of abdominal adipose tissue and hepatocellular lipid content in neonates strongly correlates with maternal BMI [17-19]. This has been also observed in offspring from pregnant obese non-human primates and mice, which exhibit increased accumulation of hepatic triglycerides and ceramides even before birth [17-19]. Furthermore, MO also relates with metabolic disturbances in the newborn, such as a reduced insulin sensitivity and altered inflammatory markers [20]. Altogether these data suggest that postnatal obesity could be programmed by MO during fetal development, however the mechanisms underlying the intrauterine programming of obesity are currently unknown. In this context inflammation, a mechanism exacerbated in pregnancies with MO, represents a potential pathway participating in this process.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]
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