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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Biosíntesis de ácidos grasos poliinsaturados de cadena larga en gamáridos

Ribes Navarro, Alberto 21 June 2025 (has links)
Tesis por compendio / [ES] El rápido crecimiento de la acuicultura ha generado una serie de problemas relacionados con la disponibilidad de ingredientes marinos esenciales en la alimentación de peces, debido a su alto contenido en ácidos grasos poliinsaturados de cadena larga (LC-PUFAs) omega-3. Una estrategia altamente innovadora para la obtención de nuevos ingredientes ricos en LC-PUFAs, consiste en el cultivo intensivo de organismos que sean capaces de producirlos a partir de fuentes que carecen de éstos, como son los subproductos de industrias agroalimentarias. Este enfoque requiere entender la capacidad biosintética del organismo en cuestión, y cómo ésta se puede modular para aumentar la acumulación de estos compuestos. Esta Tesis Doctoral plantea una serie de estudios dirigidos a esclarecer el potencial de los gamáridos para aplicar esta estrategia. La biosíntesis de LC-PUFAs en animales requiere de la acción coordinada de enzimas elongasas y desaturasas, implicadas en la conversión de ácidos grasos relativamente cortos y poco insaturados, en LC-PUFAs de alto valor nutricional. Así pues, esta Tesis Doctoral ha investigado, por un lado, la presencia y la actividad de genes involucrados en la biosíntesis de LC-PUFAs en gamáridos tanto marinos como dulceacuícolas. Por otro lado, ha estudiado cómo diferentes dietas y temperaturas afectan al metabolismo de ácidos grasos, crecimiento y supervivencia, en el gamárido marino Gammarus locusta, tanto a nivel fisiológico y composicional, como a nivel molecular. Los resultados de la primera parte demuestran que los gamáridos tienen varias elongasas, pero carecen de desaturasas. Se identificaron tres tipos de elongasas (elovl4, elovl6, y elovl1/7-like) en el gamárido marino Echinogammarus marinus, siendo elovl4 y elovl1/7-like clave para la elongación de LC-PUFAs. Este mismo patrón de elongasas se repite también para los gamáridos dulceacuícolas. Sorprendentemente, se han encontrado desaturasas front-end (fed), methyl-end (wx-des), y una elongasa del tipo Elovl2/5 únicamente en transcriptomas de gamáridos dulceacuícolas. Posteriores análisis moleculares y filogenéticos han podido determinar que estas secuencias fed, wx-des, y elovl2/5 son propias de rotíferos bdeloideos, epibiontes de gamáridos dulceacuícolas. Estos hallazgos, más allá de apuntar el potencial biosintético de los rotíferos bdeloideos, revela una relación constante entre éstos y los gamáridos en ecosistemas dulceacuícolas. La segunda parte de la Tesis analiza cómo dieta y temperatura modulan el metabolismo de ácidos grasos, crecimiento y supervivencia en Gammarus locusta. Los resultados han mostrado que G. locusta experimenta un mayor crecimiento, aunque también mayores tasas de mortalidad, cuando se cultiva a temperaturas elevadas. La mortalidad en G. locusta también aumenta cuando este se alimenta con una dieta rica en ácidos grasos saturados (SFAs) y carente de LC-PUFAs. Los perfiles de ácidos grasos en gamáridos reflejan las dietas consumidas, independientemente de la temperatura; aunque cabe destacar que los gamáridos alimentados con dietas carentes de LC-PUFAs conservan niveles apreciables de estos compuestos en sus lípidos corporales. A nivel molecular, una dieta sin LC-PUFAs y rica en SFAs disminuye el catabolismo de ácidos grasos y favorece su acumulación modulando la expresión de genes involucrados en estos procesos. Además, estas mismas condiciones afectan negativamente el desarrollo y supervivencia al influir en genes relacionados con el ciclo de muda. Además, se ha observado que temperaturas altas aceleran el desarrollo e incrementan la mortalidad. Según estos resultados, puede concluirse que las temperaturas elevadas y dietas carentes de LC-PUFAs no son adecuadas para el cultivo de G. locusta cuando el objetivo final es la obtención de biomasa rica en estos compuestos, ya que dichas condiciones afectan negativamente al perfil nutricional del animal y a su supervivencia. / [CA] El ràpid creixement de l'aqüicultura ha generat una sèrie de problemes relacionats amb la disponibilitat d'ingredients marins essencials en l'alimentació de peixos, a causa del seu alt contingut en àcids grassos poliinsaturats de cadena llarga (LC-PUFAs) omega-3. Una estratègia altament innovadora per a l'obtenció de nous ingredients rics en LC-PUFAs, consistix en el cultiu intensiu d'organismes que siguen capaços de produir-los a partir de fonts que no els ténen, com són els subproductes d'indústries agroalimentàries. Aquesta estratègia requerix entendre la capacitat biosintètica de l'organisme en qüestió, i com aquesta es pot modular per a augmentar l'acumulació d'estos compostos. Esta Tesi Doctoral planteja una sèrie d'estudis dirigits a esclarir el potencial dels gammàrids per a aplicar esta estratègia. La biosíntesi de LC-PUFAs en animals requerix de l'acció coordinada d'enzims elongases i desaturases, implicats en la conversió d'àcids grassos relativament curts i poc insaturats, en LC-PUFAs d'alt valor nutricional. Així doncs, esta Tesi Doctoral ha investigat, d'una banda, la presència i l'activitat de gens involucrats en la biosíntesi de LC-PUFAs en gammàrids tant marins com dulciaqüícoles. D'altra banda, ha estudiat com diferents dietes i temperatures afecten el metabolisme d'àcids grassos, creixement i supervivència, en el gammàrid marí Gammarus locusta, tant a nivell fisiològic i composicional, com a nivell molecular. Els resultats de la primera part demostren que els gammàrids ténen diverses elongases, però manquen de desaturases. Es van identificar tres tipus d'elongases (elovl4, elovl6, i elovl1/7-like) en el gammàrid marí Echinogammarus marinus, sent elovl4 i elovl1/7-like clau per a l'elongació de LC-PUFAs. Este mateix patró d'elongases es repetix també per als gammàrids dulciaqüícoles. Sorprenentment, s'han trobat desaturases front-end (fed), methyl-end (wx-des), i una elongasa del tipus Elovl2/5 únicament en transcriptomes de gammàrids dulciaqüícoles. Posteriors anàlisis moleculars i filogenètics han pogut determinar que estes seqüències fed, wx-des, i elovl2/5 són pròpies de rotífers bdeloides, epibionts de gammàrids dulciaqüícoles. Estes troballes, més enllà d'apuntar el potencial biosintètic dels rotífers bdeloides, revela una relació constant entre estos i els gammàrids en ecosistemes dulciaqüícoles. La segona part de la Tesi analitza com dieta i temperatura modulen el metabolisme d'àcids grassos, creixement i supervivència en Gammarus locusta. Els resultats han mostrat que G. locusta experimenta un major creixement, encara que també majors taxes de mortalitat, quan es cultiva a temperatures elevades. La mortalitat en G. locusta també augmenta quan este s'alimenta amb una dieta rica en àcids grassos saturats (SFAs) i sense LC-PUFAs. Els perfils d'àcids grassos en gammàrids reflectixen les dietes consumides, independentment de la temperatura; encara que cal destacar que els gamàrids alimentats amb dietes mancants de LC-PUFAs conserven nivells apreciables d'estos compostos en els seus lípids corporals. A nivell molecular, una dieta sense LC-PUFAs i rica en SFAs disminuïx el catabolisme d'àcids grassos i afavorix la seua acumulació modulant l'expressió de gens involucrats en estos processos. A més, estes mateixes condicions afecten negativament el desenvolupament i supervivència al influir en gens relacionats amb el cicle de muda. A més, s'ha observat que temperatures altes acceleren el desenvolupament i incrementen la mortalitat. Segons estos resultats, pot concloure's que les temperatures elevades i dietes mancants de LC-PUFAs no són adequades per al cultiu de G. locusta quan l'objectiu final és l'obtenció de biomassa rica en estos compostos, ja que estes condicions afecten negativament el perfil nutricional de l'animal i a la seua supervivència. / [EN] The rapid growth of aquaculture has generated a series of problems related to the availability of essential marine ingredients in fish feed, due to their high content of omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs). A highly innovative strategy for obtaining new ingredients rich in LC-PUFAs relies on the intensive culture of organisms that are capable of producing LC-PUFAs from sources that lack them, such as the by-products of agri-food industries. This approach requires understanding the biosynthetic capacity of the organism, and how this can be modulated to increase the accumulation of these compounds. This Doctoral Thesis proposes a series of studies aimed at clarifying the potential of gammarids to apply this strategy. LC-PUFA biosynthesis requires the coordinated action of elongase and desaturase enzymes, involved in the conversion of relatively short and poorly unsaturated fatty acids into LC-PUFAs of high nutritional value. Thus, this Doctoral Thesis has investigated, on one hand, the presence and activity of genes involved in the LC-PUFAs biosynthesis in both marine and freshwater gammarids. On the other hand, we have studied how different diets and temperatures affect fatty acid metabolism, growth and survival, in the marine gammarid Gammarus locusta, both at a physiological and compositional level, and at a molecular level. The results of the first part demonstrate that gammarids have several elongases, but lack desaturases. Three types of elongases (elovl4, elovl6, and elovl1/7-like) were identified in the marine gammarid Echinogammarus marinus, being elovl4 and elovl1/7-like key for LC-PUFA elongation. This same pattern of elongases is also present in their freshwater counterparts. Surprisingly, front-end desaturases (fed), methyl-end (wx-des), and an Elovl2/5-type elongase have been found only in transcriptomes built from freshwater gammarids. Subsequent molecular and phylogenetic analyses have been able to determine that these fed, wx-des, and elovl2/5 sequences are typical of bdelloid rotifers, which are epibionts of freshwater gammarids. These findings, beyond pointing out the biosynthetic potential of bdelloid rotifers, reveal a constant relationship between them and gammarids in freshwater ecosystems. The second part of the Thesis focuses on how diet and temperature modulate fatty acid metabolism, growth and survival in Gammarus locusta. The results have shown that G. locusta experiences greater growth, but also higher mortality rates, when grown at higher temperatures. Mortality in G. locusta also increases when it is fed with a diet rich in saturated fatty acids (SFAs) and lacking LC-PUFAs. Fatty acid profiles in gammarids reflect the diets consumed, regardless of temperature; although it is worth noting that gammarids fed with diets lacking LC-PUFAs still show levels of these compounds in their body lipids. At a molecular level, a diet lacking LC-PUFAs and rich in SFAs decreases the catabolism of fatty acids and enhances their accumulation by modulating the expression of genes involved in these processes. Furthermore, these same conditions negatively affect development and survival by influencing genes related to the molting cycle. In addition, it has been observed that higher temperatures accelerate development and increase mortality. According to these results, it can be concluded that higher temperatures and diets lacking LC-PUFAs are not suitable for the culture of G. locusta when the final outcome is to obtain a biomass rich in these compounds, since these conditions negatively affect the nutritional profile of the animal and its survival. / This research was supported by the ERA-NET BlueBio COFUND Project SIDESTREAM (Grant ID 68), co-funded through national funds provided by the Agencia Estatal de Investigación, Spain, grant no. PCI2020-111960/MCIN/AEI/10.13039/501100011033, the German Federal Ministry of Education and Research (BMBF), FKZ161B0950B, and the Fundação para a Ciência e a Tecnologia, Por- tugal (BLUEBIO/0005/2019). Additional funding was received through the project IMPROMEGA Agencia Española de Investigación, Spain, grant no. RTI2018-095119-B-100, MCIU/AEI/FEDER/UE/ MCIN/AEI/10.13039/501100011033/ and FEDER ‘A way to make Europe / Ribes Navarro, A. (2024). Biosíntesis de ácidos grasos poliinsaturados de cadena larga en gamáridos [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/207006 / Compendio
232

Déterminants nutritionnels précoces du neurodéveloppement des enfants de l'étude EDEN : rôle des acides gras polyinsaturés / Early nutritional determinants of neurodevelopment among children from the Eden study : role of polyunsaturated fatty acids

Bernard, Jonathan 18 December 2013 (has links)
Contexte : De la conception à l’âge adulte, de nombreux déterminants environnementaux influencent le neurodéveloppement. Des études montrent que durant la fin de la grossesse et les premiers mois de vie, une grande quantité d’acides gras polyinsaturés (AGPI), notamment à longue chaîne (AGPI-LC), se fixe dans le tissu cérébral. Un apport optimal durant ces périodes critiques pourrait soutenir précocement le bon développement du cerveau et de ses fonctions.Objectifs : Étudier les relations entre les expositions pré- et postnatales précoces aux AGPI, et le neurodéveloppement d’enfants de 2 et 3 ans.Population : Les données utilisées étaient celles de l’étude EDEN, une cohorte mère enfant ayant recruté 2002 femmes enceintes dans les maternités de Nancy et Poitiers entre 2003 et 2006. L’alimentation maternelle pendant la grossesse a été évaluée par un questionnaire de fréquence alimentaire et une table de composition nutritionnelle. Quatre questionnaires postnatals ont permis d’évaluer la durée d’allaitement maternel, et la composition lipidique du colostrum des mères allaitantes a été analysée par chromatographie en phase gazeuse. Des questionnaires parentaux (2 et 3 ans) et un examen neuropsychologique (3 ans) ont permis d’évaluer plusieurs aspects du neurodéveloppement. Les analyses statistiques ont été réalisées par régressions linéaires multivariées, après ajustement sur de nombreux facteurs de confusion potentiels.Résultats : Les scores de neurodéveloppement à 2 et 3 ans des enfants allaités étaient plus élevés que ceux des enfants non allaités. Chez les enfants allaités, la durée d’allaitement maternel était associée positivement au neurodéveloppement. Le rapport n 6/n 3 dans l’alimentation maternelle en acides gras en fin de grossesse était négativement associé à plusieurs mesures du neurodéveloppement, et cette association était renforcée chez les enfants non allaités. La composition du colostrum en AGPI et en AGPI-LC reflétait amplement les apports nutritionnels en AGPI et en AGPI-LC en fin de grossesse. L’utilisation de matières grasses alimentaires était aussi associée à la composition du colostrum. Les différences de neurodéveloppement des enfants allaités ne semblait pas être expliquées par la composition du colostrum en AGPI ni en AGPI-LC, à l’exception de la teneur en acide linoléique qui était négativement associée à certaines mesures du neurodéveloppement. Dans l’ensemble, les associations avec le neurodéveloppement étaient plus fréquemment retrouvées avec les questionnaires parentaux, mais certaines évaluations par les psychologues venaient parfois conforter ces résultats.Conclusion : Associés à ceux de la littérature, ces résultats soulignent le rôle notable des AGPI durant les périodes pré- et postnatale précoce pour le neurodéveloppement de l’enfant. Le suivi des enfants de l’étude EDEN jusqu’à leur 5 ans permettra d’étudier la persistance de ces résultats. Dans une perspective de santé publique, ces travaux rappellent la nécessité de promouvoir l’allaitement maternel dans la durée et de surveiller l’équilibre des apports nutritionnels en AGPI pendant la grossesse et la période de lactation. / Context: From conception to adulthood, many environmental determinants influence neurodevelopment. Studies showed that in late pregnancy and the first months of life, a large amount of polyunsaturated fatty acids (PUFA), especially long-chain-PUFA (LCPUFA), accretes in the brain. Optimal intake during these critical periods could support the brain development and its cognitive functions.Aims: To investigate the relationships between pre- and early postnatal exposures to PUFA, and neurodevelopment of 2 and 3 years old children.Population: Data were those from the EDEN mother-child cohort study, in which 2002 pregnant women were recruited between 2003 and 2006 in the maternities of Nancy and Poitiers. Maternal food intake during pregnancy was evaluated by food frequency questionnaire combined with a food composition table. Duration of breastfeeding was assessed by 4 postnatal questionnaires. Lipids in colostrum of breastfeeding mothers were analyzed by gas chromatography. Several aspects of the cognitive and motor development were assessed by both parental questionnaires (2 and 3 y) and neuropsychological examination (3 y). Statistical analyzes were performed by multiple linear regressions, after adjusting for many potential confounders.Results: At 2 and 3 years, scores of neurodevelopment were higher among breastfed children than among never breastfed children. Among breastfed children, breastfeeding duration was positively associated with neurodevelopment. Maternal dietary n 6/n 3 ratio during late pregnancy was negatively associated with measures of neurodevelopment, and this association was reinforced among never breastfed children. Colostrum composition in PUFA and LCPUFA greatly reflected maternal intake during pregnancy. Use of oils/fats for cooking and seasoning was associated with colostrum composition. The differences of neurodevelopment of breastfed children did not seem to be explained by PUFA nor LCPUFA in colostrum, except for total linoleic acid that was negatively associated with some measures of neurodevelopment. In general, associations with neurodevelopment were more frequently found with assessments by parental questionnaires, but measures by psychologists sometimes confirmed the results.Conclusion: Combined with the literature, these results underline the importance of PUFA exposures during pre- and postnatal periods for the child neurodevelopment. Follow-up of children up to 5 years will allow to investigate whether those results persist later in childhood. From a public health perspectives, this work reiterates the need to promote breastfeeding duration and to monitor the balance of PUFA intake during pregnancy and lactation periods.
233

Ostéogénie, intégration et qualité de la nacre d’un bivalve des côtes tunisiennes : Pinctada radiata (Leach, 1814) / Osteogenie, integration and quality of nacre of a tunisian coast bivalve Pinctada Radiata (Leach, 1814)

Ben Ammar, Rym 15 December 2014 (has links)
La couche de nacre de la coquille de l'huître perlière Pinctada radiata des côtes tunisiennes est considérée comme un biomatériau ostéogénique prometteur. L’objectif de ce travail intitulé « Ostéogénie, intégration et qualité de la nacre d’un bivalve des côtes tunisiennes : Pinctada radiata (Leach, 1814) » consiste dans un premier temps à valoriser l’espèce P. radiata par sa qualité nutritionnelle par un suivi saisonnier de la composition de sa chair en lipides totaux et en phospholipides particulièrement les PC, PE, PS et PI. Les analyses effectuées ont montré que les lipides de P.radiata sont caractérisés par une richesse en acides gras polyinsaturés (AGPI) de la série n-3 qui dépasse 3 fois celle des AGPI de la série n-6. Ces AGPI de la série n-3 en particulier l’EPA (C20:5n-3) et le DHA (C22:6n-3), sont connus comme étant les AG les plus importants dans l’alimentation humaine puisqu’ils préviennent des maladies cardiovasculaires et des pathologies ostéo-articulaires. Par ailleurs, P. radiata de la région de Maharès présente la meilleure qualité de nacre en Tunisie. Les analyses biochimiques ont montré que cette région, constitue la meilleure localisation de cette espèce qui est loin des zones portuaires et des différentes origines de stress (pêche, exploitation, zone touristique etc…). En plus de cet aspect, la zone de Maharès renferme des pintadines présentant une bonne qualité en termes d’épaisseur de nacre. Nos résultats montrent que la composition, saisonnière, en acide gras des phospholipides et en particulier des glycérophospholipides (PE, PI, PS et PC) de la nacre est riche en acides gras saturés C14 :0, C16 :0 et C18 :0 particulièrement en hiver et dans un moindre degré au printemps. La nacre, substance ostéogénique, a été également caractérisée par un taux élevé de plusieurs AGPI de la série n-3 et n-6, particulièrement (18:3n-3, 18:4n-3, 20:5n-3, 22:5n-3, 22:6n-3 et le 20:4n-6). Pour démontrer les potentialités ostéogéniques des extraits de la nacre, nous avons utilisé un modèle "in vitro" utilisant 4 extraits lipidiques : l’extrait lipidique de la nacre de P.radiata (Ln), l’extrait lipidique de la chair de P.radiata (Lc), l’ESM (Ethanol soluble Matrix) de la nacre de P.radiata (Br) et l’ESM de la nacre de P.margaritifera (Bm). Nous avons comparé, in vitro, le pouvoir ostéogénique des extraits ESM des deux espèces P. radiata et P. margaritifera sur deux types de cellules les préchondrocytes ATDC5 et les préostéoblastes murins MC3T3. Les différents extraits (Ln, Lc, Br et Bm) induisent l’engagement des cellules MC3T3 vers le lignage ostéoblastique par l’activation des promoteurs des gènes spécifiques du tissu osseux, tels que: le collagène de type 1, l’ostéocalcine (OC), l’ostéopontine(OP) et le Runx2. Ces extraits induisent aussi l’engagement des cellules ATDC5 vers la différenciation endochondrale par l’activation des promoteurs des gènes spécifiques du tissu osseux, tels que: le collagène de type 1 alpha-1 (Col1a1), l’Aggrécane et le collagène de type X alpha-1 (ColXA1). De plus, nous remarquons que la fraction organique ou ESMr(Br) en comparaison avec celle de P.margaritifera (Bm) présente également les propriétés stimulantes de la nacre et la stimulation est même beaucoup plus importante. Ces résultats mettent en évidence, dans les modèles expérimentaux mis en oeuvre, l’intérêt des lipides. Ces derniers semblent jouer un rôle important dans cette stimulation. De plus, nous pouvons penser à la possibilité de l’association des molécules de nacre ou de biominéralisation avec les acides gras de la nacre et de la chair dans les défauts osseux à travers les sites actifs de l’os ou du cartilage humain présentant les différentes pathologies ostéarticulaires / The nacre layer of the shell of the pearl oyster Pinctada radiata of tunisian coast is considered a promising osteogenic biomaterial. The objective of this work entitled "Osteogenie, integration and quality of nacre of a tunisian coast bivalve: Pinctada radiata (Leach, 1814)" is a first step to enhance the species P.radiata its nutritional quality by seasonal monitoring of the composition of the flesh of total lipids and phospholipids in particular PC, PE, PS and PI. The analyzes showed that lipids of P.radiata are characterized by rich in polyunsaturated fatty acids (PUFAs) of the n-3 more than 3 times that of PUFAs n-6 series. These PUFAs of the n-3 series particularly EPA (C20: 5n-3) and DHA (C22: 6n-3) are known to be the most important AG in the food as prevent of the cardiovascular disease, and joint/ bone pathologies. Moreover, P. radiata of Mahares region has the best quality of nacre in Tunisia. Biochemical analyzes showed that this region is the best location of this species that is far from the port areas and different sources of stress (fishing, exploitation, tourist area etc ...). In addition to this aspect, the area contains pintadines having good quality in terms of thickness of nacre. Our results show that the seasonal composition of fatty acid of phospholipids in particular glycerophospholipids (PE, PI, PS and PC) nacre is rich in saturated fatty acids C14: 0, C16: 0 and C18: 0 especially in winter and spring in a lesser degree. Nacre, osteogenic substance, was also characterized by a high rate of PUFA of the n-3 and n-6 rate, especially (18: 3n-3, 18: 4n-3, 20: 5n-3, 22 5n-3, 22: 6n-3 and 20: 4n-6). To demonstrate the osteogenic potential of extracts of nacre, we have established an "in vitro" model using 4 lipid extracts: the lipid extract of nacre P.radiata (Ln); the lipid extract of the flesh of P.radiata (Lc), ESM (Ethanol soluble Matrix) of the mother-of P.radiata (Br) and ESM nacre of P. margaritifera (Bm). We compared “in vitro” osteogenic power ESM extracts of both species P. radiata and P. margaritifera on two types of cells the préchondrocytes ATDC5 and the murine preosteoblasts MC3T3. The different extracts (Ln, Lc, Br and Bm) induce engagement MC3T3 osteoblast lineage cells to the activation of the promoters of specific genes of bone tissue, such as collagen type 1, osteocalcin (OC), osteopontin (OP) and Runx2. These extracts also induce the commitment of ATDC5 cells to endochondral differentiation by activating specific genes promoters of bone tissue, such as collagen type 1 alpha 1 (COL1A1), the aggrecan and collagen type alpha 1-X (ColXA1). Moreover, we note that the organic fraction or ESMR (Br) compared with that of P. margaritifera (Bm) also has stimulant properties of nacre and the stimulation is even more important. These results demonstrate, in experimental models used, the interest of lipids. They seem to play an important role in this stimulation. Moreover, we can think about the possibility of the association of molecules or nacre biomineralization with the fatty acids of the nacre and flesh in bone defects through the active sites of bone or cartilage presenting the human osteoarticular different pathologies
234

Padrões alimentares, nutrientes do metabolismo do folato e homocisteína e três desfechos em saúde / Dietary patterns, nutrients involved in one-carbon metabolism and three health outcomes

Teixeira, Juliana Araujo 05 June 2018 (has links)
Introdução - Os hábitos alimentares e os nutrientes da via metabólica do folato e homocisteína possuem grande importância na manutenção da saúde. Objetivo - Investigar a relação entre padrões alimentares (PAs) e os nutrientes envolvidos nessa via metabólica, com medidas antropométricas do recém-nascido, duração da infecção por HPV em homens e concentrações de homocisteína (Hcy) em adultos. Métodos - Foram utilizados dados dos estudos de coorte ProcriAr (Influência dos fatores nutricionais e poluentes atmosféricos urbanos na saúde pulmonar de crianças: um estudo de coorte com gestantes da zona oeste do município de São Paulo, n=299); e HIM (História natural da infecção por HPV em homens, n=1.194); e do estudo transversal ISA-Capital 2008 (Inquérito de saúde do estado de São Paulo, n=281). Os padrões alimentares foram derivados por análise fatorial por componentes principais nos estudos ProcriAr e ISA-Capital 2008 e utilizando reduced rank regression (RRR) no estudo HIM. Modelos multivariados de regressão de Poisson e lineares foram utilizados nos estudos ProcriAr e HIM para identificar a relação entre PAs e medidas antropométricas do recém-nascido e duração da infecção por HPV em homens, respectivamente. Utilizando modelo de equação estrutural, investigou-se a relação entre PAs, concentrações bioquímicas de folato, vitamina B12 e ácido docosahexaenoico (DHA) e concentrações de homocisteína em adultos do estudo ISA-Capital, considerando polimorfismo da enzima metilenotetrahidrofolato redutase (MTHFR 677C>T). Os três estudos utilizaram questionário de frequência alimentar para avaliação do consumo alimentar. Resultados - No estudo ProcriAr, a maior adesão materna ao PA \"Snacks, sanduíches, doces e refrigerantes\", rico em energia, gordura, e folato sintético, esteve diretamente associada a ter um filho pequeno ao nascer (peso e/ou comprimento ao nascer, ajustado pela idade gestacional, abaixo do percentil 10 - INTERGOWTH-21st) (RR: 2,01; IC 95%: 1.13-3.57). No estudo HIM, homens com maior adesão ao \"PA3\" tiveram, em média, um aumento de 1,15 (IC95% 0,09-2,21) à 1,18 (IC95% 0,11-2,24) meses na duração da infecção por HPV. O \"PA3\" esteve positivamente correlacionado com vitamina B6 (r = 0,59), vitamina B12 (0,27) e DFE (0,07) e negativamente correlacionado com DHA (-0,37). No estudo ISA-Capital o PA \"Prudente\" esteve inversamente associado à concentração de Hcy (β = -0,12). O DHA esteve diretamente associado ao PA \"Prudente\"; composto por verduras e legumes, peixe, frutas, frango, suco natural e batata/mandioca/polenta (cozida ou assada). Conclusões - Os PAs estão associados às medidas antropométricas do recém-nascido, à duração da infecção por HPV em homens e às concentrações de homocisteína em adultos. Estes resultados reforçam a importância de estudos sobre alimentação e nutrição que considerem não somente nutrientes, mas principalmente o consumo de alimentos e suas combinações, servindo como base para a elaboração de estratégias e políticas públicas de promoção à saúde. / Introduction - The dietary habits and nutrients involved in one-carbon metabolism are of great importance in health. Objective - To investigate the relationship between dietary patterns (DP) and the nutrients involved in this metabolism, with newborn\'s anthropometric measurements, duration of HPV infection in men, and homocysteine (Hcy) levels in adults. Methods - Data from the cohort studies ProcriAr (Influence of nutritional factors and urban air pollutants on the pulmonary health of children: a cohort study with pregnant women from the western region of the city of São Paulo, n=299); and HIM (Natural history of HPV infection in men, n=1,194); and the cross-sectional study ISA-Capital 2008 (São Paulo State Health Survey, n=281) were used. The DP were estimated using factor analysis with principal component\'s estimation in ProcriAr and ISA-Capital 2008 studies and using reduced rank regression (RRR) in HIM study. Multivariate Poisson and linear regression models were used in the ProcriAr and HIM studies to identify the relationship between DP and newborn\'s anthropometric measurements and duration of HPV infection in men, respectively. Using a structural equation model, the relationship between DP, biochemical levels of folate, vitamin B12 and docosahexaenoic acid (DHA) and homocysteine levels was investigated in adults from the ISA-Capital 2008 study, considering the polymorphism of the enzyme methylenetetrahydrofolate reductase (MTHFR 677C>T). The three studies used a food frequency questionnaire to evaluate dietary intake. Results - In the ProcriAr study, the higher maternal adherence to the \"Snacks, sandwiches, sweets and soft drinks\" DP, which is a DP rich in energy, fat, and synthetic folate, was directly associated with having a child small at birth (weight and/or birth length by gestational age and sex below the 10th percentile - INTERGOWTH-21st) (RR: 2.01, 95% CI: 1.13-3.57). In the HIM study, men with higher adherence to \"DP3\" had, on average, an increase from 1.15 (95% CI 0.09-2.21) to 1.18 (95% CI 0.11-2.24) months in the duration of HPV infection. \"DP3\" was positively correlated with vitamin B6 (r = 0.59), vitamin B12 (0.27) and DFE (0.07) and negatively correlated with DHA (-0.37). In the ISA-Capital study, the \"Prudent\" DP was inversely associated with Hcy levels (β = -0.12). DHA was directly associated with \"Prudent\" DP; composed of vegetables, fish, fruits, chicken, natural juice and potato/cassava/polenta (cooked or roasted). Conclusions - Dietary patterns are associated with newborn\'s anthropometric measurements, duration of HPV infection in men, and Hcy levels in adults. These results reinforce the importance of studies on food and nutrition that consider not only nutrients, but mainly the consumption of foods and their combinations, serving as a basis for the elaboration of public health promotion strategies and policies.
235

Endothelium-dependent vasomotor responses of hypertensive and type 2 diabetic rats: effects of sex, ageing, and therapeutic interventions

Graham, Drew January 2009 (has links)
Impaired endothelial vasomotor function is a hallmark of many chronic disease states, including essential hypertension and type 2 diabetes mellitus. Loss of the homeostatic role of the endothelium in large conduit arteries can contribute to the pathogenesis of cardiovascular conditions in these vessels (e.g. stroke, atherosclerosis). A fundamental understanding of mechanisms controlling endothelial function in hypertension and type 2 diabetes mellitus is required for appropriate clinical strategies targeting the cardiovascular conditions associated with these diseases. The vast majority of basic science studies examining endothelial function in animal models of hypertension and type 2 diabetes have been conducted in males. Studying endothelial function in females is imperative for determining potential sex-specific mechanisms of dysfunction and thus appropriate therapeutic strategies. Thus the global purpose of this thesis is to identify and characterize the pathways controlling impaired vasomotor function in female animal models of two chronic disease states: hypertension and type 2 diabetes mellitus. Chapters 2 and 3 of this thesis examine sex differences in endothelium-dependent vasorelaxation (EDR) and vasocontraction (EDC) of aortic segments isolated from male and female spontaneously hypertensive rats (SHR), a model of essential hypertension, as the animals age between 16 and 30 wk old. All endothelial vasomotor data presented in the Abstract are peak responses to 10⁻⁵ M acetylcholine. Endothelial vasomotor impairment is represented by lower EDR or by higher EDC. These present data confirmed well-established findings from the literature that 16 wk old male SHR exhibit endothelial vasomotor impairments (EDR: 77±4 %; EDC: 76±7 %) compared to normotensive Wistar-Kyoto (WKY; EDR: 89±6 %; EDC: 59±8 %; p<0.05) controls, and that this impairment worsens with ageing in 30 wk male SHR (EDR: 63±2 %; EDC: 91±3 %; p<0.05). The observation that EDR was reduced in 30 wk female SHR (EDR: 76±4 %) compared to 16 wk counterparts (EDR: 101±2 %; p<0.05), however, was novel and interesting, as there were previously no reports of vasomotor responses in female SHR older than 19 wk. Moreover, the blunted EDR response of 30 wk female SHR approached the level of impairment exhibited by 30 wk male SHR (but was still slightly greater in females; p<0.05). The limited sex difference of the EDR within 30 wk SHR (males –13 % vs. females; p<0.05) contrasted that of 16 wk SHR (males –24 % vs. females; p<0.05), when the robust and unimpaired relaxation displayed by females was much greater than the significantly blunted response of males. Interestingly, endothelium-dependent contractions in quiescent rings were moderate and similar between 16 wk (EDC: 50±4 %) and 30 wk female SHR (EDC: 59±7 %; p=N/S) as compared to the greater contractions of males that were exacerbated with ageing (see above; p<0.05 both sex and ageing comparison). A major role has been established for the cyclooxygenase (COX)-1-thromboxane A₂/prostaglandin (TP) receptor pathway in the impaired endothelial vasomotor function of male SHR. Indeed, a similar mechanism appears to be responsible for the dysfunction observed in 30 wk female SHR in this thesis since robust endothelial function was restored in these animals with both antagonism of TP receptor (EDR: 111±2 %; EDC: 7±2 %; p<0.05) and preferential inhibition of COX-1 (EDR: 112±3 %; EDC: –5±3 %; p<0.05). In contrast, preferential inhibition of COX-2 only partially tempered endothelial impairments of 30 wk female SHR (EDR: 99±5 %; EDC: 27±3 %; p<0.05), suggesting that, similar to ageing male SHR, this isoform makes at most a secondary contribution to the dysfunction in 30 wk female SHR. Collectively, these data indicate that ageing female SHR exhibit a mechanism of endothelial impairment that is similar to that of male SHR and that is largely COX-1- and TP receptor-dependent. Chapter 4 examines the ability of chronic dietary administration of the n-3 polyunsaturated fatty acid (PUFA), docosahexaenoic acid (DHA, 22:6 n-3), to ameliorate endothelial vasomotor function in adult male SHR with established hypertension. The impaired endothelial function of aortic segments isolated from adult male SHR (EDR: 48±6 %) was not improved following 10–12 wk of DHA feeding (EDR: 45±5 %; p=N/S). This finding was unexpected since it has been shown in the literature that feeding other n-3 PUFAs improves vasomotor responses in younger SHR, in which hypertension and its associated consequences are still developing. This is the first report of the effects of n-3 PUFA on endothelial vasomotor responses in adult SHR with established hypertension. These data suggest that dietary DHA do not improve vasomotor function in adult SHR. Chapter 5 examines α₁ adrenergic contraction and EDR of aortic segments isolated from 14 wk old female Zucker diabetic fatty rats (ZDF), a genetic model of high fat diet-induced obesity and type 2 diabetes, and lean non-diabetic female Zucker Lean rats. Additionally, some ZDF received an 8 wk administration of anti-diabetic metformin drug therapy, aerobic exercise training, or a combination of the two. Maximal α₁ adrenergic contractions were over 2-fold higher in high fat-fed ZDF (1.69±0.16 g) compared to Lean (0.71±0.13 g; p<0.05). This elevation in ZDF was abolished by exercise training alone (1.02±0.17 g; p<0.05) but was not altered by metformin (1.56±0.19 g; p=N/S). In contrast to the severely impaired endothelial vasomotor function reported in male ZDF in the literature, robust EDR was observed in female ZDF (72±7 %) that was similar to Lean (75±6 %; p=N/S) and that was unaltered by exercise training (76±5 %; p=N/S) or metformin (76±6 %; p=N/S). These results indicate that enhanced α₁ adrenergic contraction is a mechanism of altered vasomotor function in female type 2 diabetic ZDF rats and that it could possibly be addressed by a chronic exercise training intervention. The main novelty of the thesis is the extension of the current understanding of endothelial vasomotor function to hypertensive and type 2 diabetic females. The knowledge gained from examining mechanisms involved in endothelial impairments in ageing hypertensive females and from testing the therapeutic potential of currently used anti-diabetic interventions in the type 2 diabetic female vasculature has interesting potential application. This basic scientific information could help direct clinical therapeutic strategies to target population-specific mechanisms of dysfunction. Understanding female sex-specific endothelial behaviour in patient populations is important for describing cardiovascular complications, defining mechanisms, and applying appropriate therapeutic targets. Findings from this thesis indicate a sex-dependence of the total divergence of endothelial function (e.g. female type 2 diabetic rats vs. male counterparts in the literature) and of the interaction of disease variables (e.g. age) and endothelial vasomotor responses.
236

Endothelium-dependent vasomotor responses of hypertensive and type 2 diabetic rats: effects of sex, ageing, and therapeutic interventions

Graham, Drew January 2009 (has links)
Impaired endothelial vasomotor function is a hallmark of many chronic disease states, including essential hypertension and type 2 diabetes mellitus. Loss of the homeostatic role of the endothelium in large conduit arteries can contribute to the pathogenesis of cardiovascular conditions in these vessels (e.g. stroke, atherosclerosis). A fundamental understanding of mechanisms controlling endothelial function in hypertension and type 2 diabetes mellitus is required for appropriate clinical strategies targeting the cardiovascular conditions associated with these diseases. The vast majority of basic science studies examining endothelial function in animal models of hypertension and type 2 diabetes have been conducted in males. Studying endothelial function in females is imperative for determining potential sex-specific mechanisms of dysfunction and thus appropriate therapeutic strategies. Thus the global purpose of this thesis is to identify and characterize the pathways controlling impaired vasomotor function in female animal models of two chronic disease states: hypertension and type 2 diabetes mellitus. Chapters 2 and 3 of this thesis examine sex differences in endothelium-dependent vasorelaxation (EDR) and vasocontraction (EDC) of aortic segments isolated from male and female spontaneously hypertensive rats (SHR), a model of essential hypertension, as the animals age between 16 and 30 wk old. All endothelial vasomotor data presented in the Abstract are peak responses to 10⁻⁵ M acetylcholine. Endothelial vasomotor impairment is represented by lower EDR or by higher EDC. These present data confirmed well-established findings from the literature that 16 wk old male SHR exhibit endothelial vasomotor impairments (EDR: 77±4 %; EDC: 76±7 %) compared to normotensive Wistar-Kyoto (WKY; EDR: 89±6 %; EDC: 59±8 %; p<0.05) controls, and that this impairment worsens with ageing in 30 wk male SHR (EDR: 63±2 %; EDC: 91±3 %; p<0.05). The observation that EDR was reduced in 30 wk female SHR (EDR: 76±4 %) compared to 16 wk counterparts (EDR: 101±2 %; p<0.05), however, was novel and interesting, as there were previously no reports of vasomotor responses in female SHR older than 19 wk. Moreover, the blunted EDR response of 30 wk female SHR approached the level of impairment exhibited by 30 wk male SHR (but was still slightly greater in females; p<0.05). The limited sex difference of the EDR within 30 wk SHR (males –13 % vs. females; p<0.05) contrasted that of 16 wk SHR (males –24 % vs. females; p<0.05), when the robust and unimpaired relaxation displayed by females was much greater than the significantly blunted response of males. Interestingly, endothelium-dependent contractions in quiescent rings were moderate and similar between 16 wk (EDC: 50±4 %) and 30 wk female SHR (EDC: 59±7 %; p=N/S) as compared to the greater contractions of males that were exacerbated with ageing (see above; p<0.05 both sex and ageing comparison). A major role has been established for the cyclooxygenase (COX)-1-thromboxane A₂/prostaglandin (TP) receptor pathway in the impaired endothelial vasomotor function of male SHR. Indeed, a similar mechanism appears to be responsible for the dysfunction observed in 30 wk female SHR in this thesis since robust endothelial function was restored in these animals with both antagonism of TP receptor (EDR: 111±2 %; EDC: 7±2 %; p<0.05) and preferential inhibition of COX-1 (EDR: 112±3 %; EDC: –5±3 %; p<0.05). In contrast, preferential inhibition of COX-2 only partially tempered endothelial impairments of 30 wk female SHR (EDR: 99±5 %; EDC: 27±3 %; p<0.05), suggesting that, similar to ageing male SHR, this isoform makes at most a secondary contribution to the dysfunction in 30 wk female SHR. Collectively, these data indicate that ageing female SHR exhibit a mechanism of endothelial impairment that is similar to that of male SHR and that is largely COX-1- and TP receptor-dependent. Chapter 4 examines the ability of chronic dietary administration of the n-3 polyunsaturated fatty acid (PUFA), docosahexaenoic acid (DHA, 22:6 n-3), to ameliorate endothelial vasomotor function in adult male SHR with established hypertension. The impaired endothelial function of aortic segments isolated from adult male SHR (EDR: 48±6 %) was not improved following 10–12 wk of DHA feeding (EDR: 45±5 %; p=N/S). This finding was unexpected since it has been shown in the literature that feeding other n-3 PUFAs improves vasomotor responses in younger SHR, in which hypertension and its associated consequences are still developing. This is the first report of the effects of n-3 PUFA on endothelial vasomotor responses in adult SHR with established hypertension. These data suggest that dietary DHA do not improve vasomotor function in adult SHR. Chapter 5 examines α₁ adrenergic contraction and EDR of aortic segments isolated from 14 wk old female Zucker diabetic fatty rats (ZDF), a genetic model of high fat diet-induced obesity and type 2 diabetes, and lean non-diabetic female Zucker Lean rats. Additionally, some ZDF received an 8 wk administration of anti-diabetic metformin drug therapy, aerobic exercise training, or a combination of the two. Maximal α₁ adrenergic contractions were over 2-fold higher in high fat-fed ZDF (1.69±0.16 g) compared to Lean (0.71±0.13 g; p<0.05). This elevation in ZDF was abolished by exercise training alone (1.02±0.17 g; p<0.05) but was not altered by metformin (1.56±0.19 g; p=N/S). In contrast to the severely impaired endothelial vasomotor function reported in male ZDF in the literature, robust EDR was observed in female ZDF (72±7 %) that was similar to Lean (75±6 %; p=N/S) and that was unaltered by exercise training (76±5 %; p=N/S) or metformin (76±6 %; p=N/S). These results indicate that enhanced α₁ adrenergic contraction is a mechanism of altered vasomotor function in female type 2 diabetic ZDF rats and that it could possibly be addressed by a chronic exercise training intervention. The main novelty of the thesis is the extension of the current understanding of endothelial vasomotor function to hypertensive and type 2 diabetic females. The knowledge gained from examining mechanisms involved in endothelial impairments in ageing hypertensive females and from testing the therapeutic potential of currently used anti-diabetic interventions in the type 2 diabetic female vasculature has interesting potential application. This basic scientific information could help direct clinical therapeutic strategies to target population-specific mechanisms of dysfunction. Understanding female sex-specific endothelial behaviour in patient populations is important for describing cardiovascular complications, defining mechanisms, and applying appropriate therapeutic targets. Findings from this thesis indicate a sex-dependence of the total divergence of endothelial function (e.g. female type 2 diabetic rats vs. male counterparts in the literature) and of the interaction of disease variables (e.g. age) and endothelial vasomotor responses.
237

Métabolisme et intérêt nutritionnel de l’acide docosapentaénoïque n-3 : modulation du statut tissulaire en acides gras n-3 par les lipides laitiers alimentaires chez le rat / Metabolism and nutritional interest of n-3 docosapentaenoic acid : modulation of n-3 fatty acid status in tissues by dietary dairy lipids in rats

Drouin, Gaëtan 03 July 2018 (has links)
L’optimisation du statut tissulaire en acides gras polyinsaturés à longues chaines n-3 (AGPILC n-3) fait partie des objectifs actuels en nutrition humaine. En effet, de nombreux effets bénéfiques sur la santé humaine ont été démontrés pour ces différents AGPILC n-3. Néanmoins, la bioconversion de ces dérivés à partir de leur précurseur alimentaire, l’acide α-linolénique, est limitée chez l’Homme et ne permet pas de subvenir aux besoins. Parmi cette famille d’acides, l’acide docosahexaénoïque (DHA) et de l’acide eicosapentaénoïque (EPA) ont été largement étudiés à l’inverse de ceux de l’acide docosapentaénoïque n-3 (DPA). Le premier objectif de ces travaux a été d’étudier l’impact d’une supplémentation nutritionnelle en DPA sur le métabolisme des acides gras et le métabolisme lipidique chez le rat sain. Pour cela, une méthode de purification du DPA à haute pureté et en grande quantité par chromatographie liquide a tout d’abord été mise en place. Ce résultat participe à faciliter la recherche future des effets in vivo du DPA dont la disponibilité commerciale est faible. Après sa supplémentation nutritionnelle, le DPA a été incorporé dans de multiples tissus et a impacté les compositions tissulaires en AGPILC n-3 de certains organes spécifiques comme le foie, le cœur, le poumon, la rate et le rein. Ainsi, la supplémentation en DPA pourrait être une source d’EPA, de DPA, et dans une moindre mesure de DHA. Enfin, comparé à une supplémentation en EPA ou en DHA, le DPA a été l’AGPILC n-3 le plus puissant pour améliorer la triglycéridémie et la cholestérolémie des animaux. Ces informations participeront certainement à une prise en compte plus importante du DPA tant dans les études nutritionnelles ainsi que dans l’installation des futures recommandations nutritionnelles. Le deuxième axe de recherche a porté sur la capacité d’une incorporation partielle de lipides laitiers dans le régime à augmenter le statut tissulaire en AGPI-LC n-3. L’incorporation de lipides laitiers a augmenté le statut en DHA cérébral et rétinien et le statut en DPA dans les autres tissus étudiés. De plus, l’induction de la conversion des AGPILC n-3 à partir de leur précurseur par les lipides laitiers a été complémentaire avec la supplémentation en DPA pour augmenter le statut tissulaire en AGPI-LC n-3. Ces résultats s’insèrent dans un contexte de nutrition infantile, période pendant laquelle l’incorporation des AGPI-LC n-3 est maximale dans les tissus nerveux. Ainsi, ces résultats apportent des données intéressantes tant pour les entreprises que pour les professionnels de santé pour recommander à la consommation des formules infantiles contenant des lipides laitiers. / The optimization of tissue status in n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) is one of the current goals in human nutrition. Indeed, many beneficial effects on human health have been demonstrated for these different n-3 LCPUFA. However, the bioconversion of these derivatives from their food precursor, α-linolenic acid, is limited in humans and it does not meet the needs of the organism. Among this family of fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been widely studied in contrast to those of n-3 docosapentaenoic acid (DPA). The first objective of this work was to study the impact of dietary supplementation with DPA on fatty acid metabolism and lipid metabolism in healthy rats. For this, a method for purifying DPA with high purity and in large quantities by liquid chromatography was first established. This result helps future research of the in vivo effects of DPA, poorly commercially available. After its nutritional supplementation, DPA was incorporated into multiple tissues and it has affected the n-3 LCPUFA tissue compositions of specific organs such as the liver, heart, lung, spleen and the kidney. Thus, supplementation with DPA could be a source of EPA, DPA, and to a lesser extent DHA. Finally, compared to supplementation with EPA or DHA, DPA was the most potent n-3 LCPUFA to improve triglyceridemia and cholesterolemia in animals. This information will certainly contribute to a greater consideration of DPA both in nutritional studies and in the direction of future nutritional recommendations. The second area of ​​research focused on the ability of a partial incorporation of dairy lipids in the diet to increase the tissue status in n-3 LCPUFA. Incorporation of dairy lipids in the diet increased DHA status in brain and retina and DPA status in the other studied tissues. In addition, the induction of conversion of n-3 LCPUFA from their precursor by dairy lipid was complementary with the DPA supplementation to increase n-3 LCPUFA status in tissues. These results fit into a context of infant nutrition, during which the incorporation of n-3 LCPUFA is maximal in nervous tissues. Thus, these results provide interesting data for both companies and health professionals to recommend infant formulas containing dairy lipids for consumption.
238

Vliv n-3 polynenasycených mastných kyselin na rozvoj nealkoholového jaterního postižení v experimentu, výskyt u pacientů s diabetem mellitem 2. typu a metabolickým syndromem, možnosti neinvazivní diagnostiky / Effects of n-3 polyunsaturated fatty acids on development of non-alcoholic fatty liver disease in experiment, prevalence in patients with type 2 diabetes mellitus and metabolic syndrome, non-invasive diagnostics

Dvořák, Karel January 2015 (has links)
This thesis focuses on the effects of n-3 polyunsaturated fatty acids (n-3 PUFA) on development of non-alcoholic fatty liver disease (NAFLD) in experiment, on prevalence of this condition in patients with type 2 diabetes mellitus and metabolic syndrome and also on non-invasive diagnostics. The aim was to study the effect of n-3 PUFA on NAFLD development in an experimental model and based on analysis of a group of patients with type 2 diabetes and metabolic syndrome to assess the prevalence of this condition. Lastly we aimed to evaluate non-invasive diagnostic methods of liver fibrosis and NASH. We demonstrated beneficial effects of n-3 PUFA administration on NAFLD development in a C57/Bl6 mice high fat methionin-cholin defficient dietary model of NAFLD. n-3 PUFA administration led to biochemical improvement, decrease of lipid accumulation in the liver as well as improvement of histology. These effects are determined by complex modulation of lipid metabolism, mainly due to decrease in availability of fatty acids for triglyceride synthesis in the liver, changes of adipokine levels and amelioration of proinflammatory status in the liver. In a group of type 2 diabetics we found NAFLD prevalence of almost 80%, 14% of these patients had also signs of liver fibrosis or cirrhosis. Non-invasive methods...
239

Le vieillissement membranaire cérébral : conséquences fonctionnelles et protection par les acides gras polyinsaturés oméga-3 alimentaires / Membrane brain aging : functional outcomes and protection by dietary omega-3 polyunsatured fatty acids

Colin, Julie 19 June 2015 (has links)
Un des phénomènes sociétaux marquants de ces dernières années est le vieillissement de la population et en conséquence, une hausse considérable du nombre de personnes âgées. Dans ce contexte, la recrudescence des pathologies chroniques liées au vieillissement, dont la maladie d’Alzheimer, est devenue un enjeu majeur de santé publique. L’impact de nombreux facteurs environnementaux modulables, l’aspect chronique et évolutif des mécanismes pathogènes mis en jeu, doivent inciter à développer des interventions préventives permettant de minimiser les risques de développer ces maladies liées au vieillissement. Ce travail nous a permis de mettre en évidence l’importance d’utiliser des modèles d’étude et des modes d’expérimentation adaptés au vieillissement pour espérer en ralentir ou retarder les processus délétères. Nos résultats ont aussi permis d’identifier les membranes comme des éléments essentiels au bon fonctionnement cérébral. L’altération de la composition et de l’architecture des membranes neuronales chez la souris âgée perturbe leurs fonctionnalités et diminue les capacités de réponse neuroprotectrices recherchées notamment lors des thérapies anti-Alzheimer. Nous avons aussi observé des modifications membranaires comparables chez les souris rendues dyslipidémiques par un régime alimentaire excessif en lipides saturés auquel nous avons pu clairement attribuer un rôle pro-vieillissement. Nous avons finalement démontré le potentiel préventif d’une supplémentation alimentaire en acide docosahexaénoïque, l’acide gras polyinsaturé à longue chaîne majoritaire dans le cerveau, et pu conclure en sa capacité de restaurer une réponse neuroprotectrice altérée chez la souris âgée / One of the marked societal phenomena in recent decades is the aging of populations due to continually increasing lifespans and as a result, a considerable surge in the number and proportion of elderly, particularly in Western countries. In this demographic context, the rise of chronic diseases related to aging, including Alzheimer’s disease and other types of dementia, has become a major public health issue. The impact of modifiable environmental factors, evolution of the pathogenic mechanisms involved, and the lack of curative treatments illustrates the need for the development of interventions to prevent or delay the onset of these aging-related diseases. The present work demonstrates the importance of using age-adapted study models and experimental methods with the goal towards slowing or delaying age-related deleterious processes. Secondly, our results have identified membranes as an essential part for normal brain function. The composition and architectural changes in the neuronal membranes of elderly mice disrupt their functionality and reduce neuroprotective responsiveness such as those sought by anti-Alzheimer’s therapies. We also observed similar pro-aging-type changes in brain membranes of dyslipidemic mice fed a high-fat diet. Thus, disturbances of lipid homeostasis are correlated with an increased risk of developing aging-related cardiovascular and metabolic as well as neurodegenerative diseases. We finally demonstrated the preventive potential of dietary supplementation with docosahexaenoic acid, the most abundant long-chain polyunsaturated fatty acid in the brain, and observed its ability to restore a neuroprotective response that was impaired in older mice
240

Vliv n-3 polynenasycených mastných kyselin na rozvoj nealkoholového jaterního postižení v experimentu, výskyt u pacientů s diabetem mellitem 2. typu a metabolickým syndromem, možnosti neinvazivní diagnostiky / Effects of n-3 polyunsaturated fatty acids on development of non-alcoholic fatty liver disease in experiment, prevalence in patients with type 2 diabetes mellitus and metabolic syndrome, non-invasive diagnostics

Dvořák, Karel January 2015 (has links)
This thesis focuses on the effects of n-3 polyunsaturated fatty acids (n-3 PUFA) on development of non-alcoholic fatty liver disease (NAFLD) in experiment, on prevalence of this condition in patients with type 2 diabetes mellitus and metabolic syndrome and also on non-invasive diagnostics. The aim was to study the effect of n-3 PUFA on NAFLD development in an experimental model and based on analysis of a group of patients with type 2 diabetes and metabolic syndrome to assess the prevalence of this condition. Lastly we aimed to evaluate non-invasive diagnostic methods of liver fibrosis and NASH. We demonstrated beneficial effects of n-3 PUFA administration on NAFLD development in a C57/Bl6 mice high fat methionin-cholin defficient dietary model of NAFLD. n-3 PUFA administration led to biochemical improvement, decrease of lipid accumulation in the liver as well as improvement of histology. These effects are determined by complex modulation of lipid metabolism, mainly due to decrease in availability of fatty acids for triglyceride synthesis in the liver, changes of adipokine levels and amelioration of proinflammatory status in the liver. In a group of type 2 diabetics we found NAFLD prevalence of almost 80%, 14% of these patients had also signs of liver fibrosis or cirrhosis. Non-invasive methods...

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