Diss. (sammanfattning) Umeå : Umeå universitet, 2010.

L’hypertension artérielle pulmonaire (HTAP) est une pathologie affectant les artères pulmonaires de petit calibre entraînant une augmentation des résistances artérielles pulmonaires aboutissant à une défaillance cardiaque droite. La vasoconstriction, le remodelage des artères pulmonaires distales, l’inflammation et le stress oxydant sont de facteurs clés de la pathogénèse de l'HTAP. Nous avons testé les potentiels de la formulation EPA:DHA 6:1 à prévenir l’hypertension pulmonaire et les altérations cardiovasculaires et pulmonaires induites par l’injection de monocrotaline chez le rat. Le traitement des rats monocrotaline avec l’EPA:DHA 6:1 (500 mg/kg/j, p.o) prévient significativement l’élévation de la pression artérielle pulmonaire moyenne, la pression systolique du ventricule droit, diminue le débit cardiaque, l’hypertrophie et la dilatation du ventricule droit. L’EPA:DHA 6:1 réduit également les résistances vasculaires pulmonaires, le remodelage des artérioles pulmonaires et les infiltrations lymphocytaires et macrophagiques. De plus, l’EPA:DHA 6:1 inhibe la production des espèces réactives de l’oxygène, diminue la surexpression des sous-unités p22phox et p47phox de la NADPH oxydase, des cyclooxygénases 1 et 2, des récepteurs ETA et ETB de l’endothéline-1, de la eNOS découplée et améliore la dysfonction endothéliale des artères pulmonaires. L’EPA:DHA 6:1 exercent des effets anti-inflammatoires, antioxydants et vasoprotecteurs et prévient le développement de l’HTAP induite par l’injection de monocrotaline chez le rat. / Pulmonary arterial hypertension (PAH) is characterized by remodeling of the small pulmonary arteries leading to a progressive increase in pulmonary vascular resistance and right ventricular failure. Pulmonary endothelial dysfunction, inflammation and oxidative stress promote the development of pulmonary hypertension. Omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA) have been shown to protect the cardiovascular system and reduce inflammation and oxidative stress. The present study evaluate the potential of EPA:DHA 6:1 to prevent monocrotaline-induced PAH in rats. EPA:DHA 6:1 treatment (500 mg/kg/d, p.o) prevented the MCT-induced mean pulmonary arterial pressure, right ventricular systolic pressure and decreased cardiac output. EPA:DHA 6:1 also attenuated right ventricular hypertrophy by reducing Fulton’s index and pulmonary arterial remodeling, decreased lymphocytes T and macrophages infiltration. EPA:DHA 6:1 treatment significantly reduced MCT-induced vascular oxidative stress and improved endothelial function in pulmonary arteries. The protective effect of EPA:DHA 6:1 was associated with the prevention of the MCT-induced upregulation of NADPH oxidase subunits (p22phox and p47phox), COX-1 and COX-2, endothelin A and B receptors and uncoupled eNOS in pulmonary arterioles. Our studies show that the EPA:DHA 6:1 formulation exerts anti-inflammatory, anti-oxidant and has a protective vascular effect in the pulmonary arteries, which may contribute to prevent and potentially cure pulmonary hypertension induced by MCT in rat.

Tesis por compendio / [ES] La presente tesis doctoral presentaba como principal objetivo contribuir al conocimiento sobre estrategias de alimentación y técnicas de producción que puedan mejorar la sostenibilidad del sector acuícola a través de un enfoque multidisciplinar, evaluando el crecimiento, la salud y la calidad sensorial de los peces, así como la producción de especies vegetales. También se evaluó El impacto ambiental de las diferentes propuestas mediante el análisis del Ciclo de Vida (LCA) como parte de la discusión general de la tesis. El primer estudio evaluó el efecto de la sustitución de diferentes niveles de aceite de pescado (FO) por aceites vegetales en piensos para la seriola mediterránea (Seriola dumerili, Risso, 1810) en el perfil de ácidos grasos (FA) de diferentes tejidos. El perfíl de FA de la grasa visceral, hígado, músculo rojo y blanco cambiaron cuando se modificó la fuente lipídica en el pienso, mientras que el perfíl de FA del tejido cerebro fue bastante resistente a su alteración por los cambios en la dieta. Estos nuevos datos podrían ayudar a evaluar si las funciones fisiológicas claves se conservan cuando los peces son alimentan con dietas con niveles bajos de FO, así como para definir las necesidades de FA en la dieta de la S. dumerili para mejorar la sostenibilidad de la producción y el bienestar de los peces. El segundo estudio evaluó los efectos de un periodo de realimentación en la composición de ácidos grasos en el músculo de la seriola mediterránea. Después de 109 días durante los cuales los peces fueron alimentados con un pienso a base de aceite de pescado (FO 100) o un pienso (FO 0) en la que el FO fue sustituido completamente por aceites vegetales, todos los peces alimentados con la dieta FO 0 fueron sometidos a una realimentamentación con un pienso FO 100, durante 90 días. Un recebo de 90 días puede mejorar parcialmente el perfil de FA en los músculos de la seriola mediterránea previamente alimentada con dietas a base de aceite vegetal.El tercero estudio analizó los efectos de dos densidades de producción (baja - ALD, 3,81 kg m¿3 frente a alta - AHD, 7,26 kg m¿3) sobre el crecimiento, la salud y la calidad de la carne de la trucha arco iris (Oncorhynchus mykiss, Walbaum 1792) así como el rendimiento y calidad microbiológica de la lechuga (Lactuca sativa, L.) producida en un sistema acuapónico de baja tecnología en comparación con el cultivo hidropónico (HYP). Las producciones de trucha arco iris y lechuga fueron exitosas en el sistema acuapónico probado, mientras que la densidad de población no afectó el crecimiento de los peces ni a la calidad de la carne. En el cuarto estudio se evaluó el efecto de la sustitución dietaria de la harina de pescado (FM) por harina de Hermetia illucens (Linnaeus, 1758), parcialmente desgrasada (HI) sobre el crecimiento, la digestibilidad del alimento, la morfología intestinal y la calidad del filete de la trucha arco iris producida en un sistema acuapónico de baja tecnología. El crecimiento de los peces y la calidad del filete no se vieron esencialmente afectados por la sustitución de harina de pescado al 25% con HI. Sin embargo, con una sustitución del 50%, se detectó ciertos efectos sobre la histología intestinal y el color del filete y las características nutricionales, que justifican una mayor investigación. en base a los resultados de esta tesis, los aceites vegetales y la harina de insecto son ingredientes alternativos prometedores para ser incluidos en las dietas de especies marinas y de agua dulce de alto valor económico. Sin embargo, las formulaciones futuras deberán centrarse no solo en las características nutricionales y el coste de los ingredientes, sino también en su impacto ambiental. La acuaponía es una técnica prometedora para la cría de especies de agua dulce de alto valor como la trucha arco iris. Además, la optimización de la densidad de producción de peces en acuaponía es un aspecto clave para obtener altos rendimientos y una buena calidad del producto. / [CA] La present tesi doctoral va tenir com a objectiu contribuir al coneixement sobre estratègies d'alimentació i tècniques de producció que puguin millorar la sostenibilitat del sector aqüícola a través d'un enfocament multidisciplinari, avaluant el creixement, la salut i la qualitat sensorial dels peixos, així com la producció de espècies vegetals. El impacte ambiental de les diferents propostes també es va avaluar mitjançant l'anàlisi de l'Cicle de Vida (LCA) com a part de la discussió general de la tesi. En el primer estudi es va avaluar la substitució de diferents nivells d'oli de peix per olis vegetals en pinsos per a la seriola Mediterrània (Seriola dumerili, Risso, 1810) en el perfil d'àcids grassos (FA) de diferents teixits. El segon estudi es van avaluar els efectes d'un període de realimentació en la composició d'àcids grassos en el múscul de la seriola mediterrània. Un rentat de 90 dies pot millorar parcialment el perfil de FA en els músculs de la seriola mediterrània prèviament alimentada amb dietes a base d'oli vegetal. El tercer estudi va estudiar els efectes de dues densitats de producció (baixa - ALD, 3,81 kg m-3 enfront de alta - AHD, 7,26 kg m-3) sobre el creixement, la salut i la qualitat de la carn de la truita (Oncorhynchus mykiss, Walbaum 1792) i el rendiment i qualitat microbiològica de l'enciam (Lactuca sativa, L.) produïda en un sistema aquapònic de baixa tecnologia en comparació amb el cultiu hidropònic (HYP). En conclusió, les produccions de truita i enciam van tindre èxit en el sistema aquapònic provat, mentre que la densitat de població no va afectar al creixement dels peixos ni a la qualitat de la carn. En el quart estudi es va avaluar l'efecte de la substitució dietària de la farina de peix amb farina de Hermetia illucens (Linnaeus, 1758), parcialment desgreixada (HI) sobre el creixement, la digestibilitat de l'aliment, la morfologia intestinal i la qualitat del filet de la truita produïda en un sistema aquapònic de baixa tecnologia, el creixement dels peixos i la qualitat de l'filet no es van veure essencialment afectats per la substitució de farina de peix al 25% amb HI, mentre que amb una substitució del 50%, es va detectar certs efectes sobre la histologia intestinal i el color del filet i les característiques nutricionals, que justifiquen una major investigació. En conclusió, en base als resultats d'aquesta tesi, els olis vegetals i la farina d'insecte són ingredients alternatius prometedors per a ser inclosos en les dietes d'espècies marines i d'aigua dolça d'alt valor econòmic. No obstant això, les formulacions futures hauran de centrar no només en les característiques nutricionals i el cost dels ingredients, sinó també en el seu impacte ambiental. La aquaponia és una tècnica prometedora per a la cria d'espècies d'aigua dolça d'alt valor com la truita. A més, l'optimització de la densitat de producció de peixos en aquaponia és un aspecte clau per obtenir alts rendiments i una bona qualitat del producte, al temps que es redueix l'impacte ambiental, assegurant la salut i el benestar dels peixos. / [EN] The present PhD thesis aimed at improving the knowledge on feeding strategies and rearing techniques that might improve the sustainability of the aquaculture sector through a multidisciplinary approach, evaluating fish growth performance, health and quality, and vegetable production. The environmental impact of the different solutions was also assessed using a Life Cycle Assessment (LCA) analysis as a part of thesis general discussion. The first contribution evaluated how replacing different levels of fish oil by vegetable oils in the diet of Mediterranean yellowtail, Seriola dumerili (Risso, 1810), affects the fatty acids (FA) signature, i.e. overall FA profile, in different tissues. The FA signatures of red and white muscle, liver, and visceral fat tissues changed when the dietary FA source changed, whereas FA signatures in the brain were rather robust to such dietary changes. The second contribution assessed the effects of a wash-out on the fatty acid composition in the muscles of Mediterranean yellowtail. A 90-d wash-out can partially improve the FA profile in muscles of Mediterranean yellowtail previously fed vegetable oil-based diets. The third contribution investigated the effects of two stocking densities (low - ALD, 3.81 kg m¿3 vs. high - AHD, 7.26 kg m¿3) on the growth, health, and flesh quality of rainbow trout (Oncorhynchus mykiss, Walbaum 1792) and the yield and microbiological quality of lettuce (Lactuca sativa, L.) produced in a low-tech aquaponic system compared to hydroponic cultivation (HYP). Rainbow trout and lettuce productions were successful in the tested aquaponic system, whereas stocking density did not affect fish growth or flesh quality. The fourth contribution evaluated the effects of dietary substitution of fishmeal with partially defatted (Hermetia illucens, Linnaeus, 1758,) meal (HI) on the growth, feed digestibility, gut morphology, and fillet quality of rainbow trout reared in a low-tech aquaponic system fish growth and fillet quality were essentially unaffected by a 25% fish meal replacement with HI, whereas at a replacement rate of 50%, certain effects on gut histology and fillet colour and nutritional characteristics were detected, which warrant further investigation. In conclusion, based on the results of the present thesis, vegetable oils and insect meal are promising alternative ingredients to be included in diets for high-value marine and freshwater carnivorous species. Nevertheless, future aquafeed formulations will be required to focus not only on the nutritional characteristics and costs of the ingredients but also on their environmental impact. Aquaponics is a promising technique to be used for rearing high-value freshwater species such as rainbow trout. Furthermore, the optimization of fish stocking density in aquaponics is a key aspect to obtain high product yields and quality, reducing the environmental impact as well as assuring fish health and welfare. / Thesis written with the financial contribution of ECCEAQUA project (MIUR; CUP: C26C18000030004) / Bordignon, F. (2022). Feeding Strategies and Rearing Techniques for a Sustainable Aquaculture [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/180851 / TESIS / Compendio

Eicosapentaenoic acid (EPA) is a polyunsaturated fatty acid (PUFA) with neuroprotective and cardioprotective properties. It is thought that some of the actions of EPA may be attributed to its elongated metabolite, the PUFA docosapentaenoic acid (DPA). Docosahexaenoic acid (DHA) and arachidonic acid (AA) are bioactive PUFA ubiquitously expressed in neural tissues. EPA and AA can be converted by cyclooxygenase (COX) to prostanoids and by lipoxygenase (LOX) to hydroxy fatty acids. PUFA can also be converted to ethanolamides in the brain. These mediators are involved in physiological and pathological processes in many bodily systems. The purpose of this study was to examine the production of eicosanoids, hydroxy fatty acids and fatty acid ethanolamides in young and aged rat brain following EPA or DPA enriched diets. The effects of specific PUFA on human platelet eicosanoid production were also investigated as these mediators play a role in adhesion and aggregation. Liquid chromatography coupled to tandem mass spectrometry (LC/ESI-MS/MS) assays were developed and used to measure lipid mediators in rat brain and human platelets. Ageing in rat brain was accompanied with several changes in the prostanoid and hydroxy fatty acid profiles. Supplementing the diet with EPA or DPA at a daily dose of 200 mg/kg for 8 weeks prevented these changes and decreased levels of PGE2. DPA changed the profile of hydroxy fatty acids synthesised in the brain tissue of young animals. This study has shown that levels of eicosapentaenoylethanolamide (EPA-EA) increase in the brain as a result of ageing and that this is accompanied by an increase in levels of anandamide. Feeding aged animals EPA or DPA further increased the levels of EPA-EA but prevented any change in the level of anandamide. Niacin is used to treat hypercholesterolaemia although it is associated with an unpleasant PGD2 mediated skin flush. This exploratory study has shown that human platelets treated with niacin did not show any changes in their prostanoid and hydroxy fatty acid profiles. Platelets treated with EPA showed increased production of TXB3 and 12-HEPE. Niacin augmented the effects of EPA on human platelet mediator synthesis. Overall, this study has demonstrated that EPA can change brain and platelet lipid mediator synthesis and has provided evidence that could explain some of the neuroprotective and cardioprotective actions of this PUFA.

Lipids are important for structural and physiological functions of neuronal cell membranes. They exhibit a range of biological effects many are bioactive lipid mediators derived from polyunsaturated fatty acids such as sphingolipids, fatty acid ethanolamides (FA-EA) and endocannabinoids (EC). These lipid mediators and oxysterols elicit potent bioactive functions in many physiological and pathological processes of the brain and neuronal tissues. They have been investigated for biomarker discovery of ageing, neuroinflammation and neurodegenerative disorders. The n-3 fatty acids EPA and DPA are thought to exhibit a range of neuroprotective effects many of which are mediated through production of such lipid mediators. The aims of this study were to evaluate the effects of n-3 EPA and n-3 DPA supplementation on RBC membranes and in this way assess dietary compliance and to investigate brain sphingomyelin species of adult and aged rats supplemented with n-3 EPA and n-3 DPA to evaluate the effects and benefits on age-related changes in the brain. Furthermore, to study the effects of lithium on the brain FA-EAs and ECs to further understand the neuroprotective effects of lithium neuroprotective action on neuroinflammation as induced by LPS. Finally to examine if circulating oxysterols are linked to the prevalence of ALS and whether RBC fatty acids are markers of this action in relation to age and disease stages. These analytes were extracted from tissue samples and analysed with GC, LC/ESI-MS/MS and GC-MS. It was found that aged rats exhibited a significant increase in brain AA and decrease in ¿n-3 and ¿n-6 PUFAs when compared to adult animals. The observed increase of brain AA was reversed following n-3 EPA and n-3 DPA supplementation. Sphingomyelin was significantly increased when aged animals were supplemented with n-3 DPA. LPS treatment following lithium supplementation increased LA-EA and ALA-EA, while it decreased DHA-EA. Both oxysterols 24-OH and 27-OH increased in ALS patients and SOD1-mice. Eicosadienoic acid was different in ASL-patients compared to aged SOD1-mice. These studies demonstrated that dietary intake of n-3 EPA and n-3DPA significantly altered RBC fatty acids and sphingolipids in rat brain. They suggest that n-3 DPA can be a potential storage form for EPA, as shown by retro-conversion of n-3 DPA into EPA in erythrocyte membranes, ensuring supply of n-3 EPA. Also, n-3 EPA and n-3 DPA supplementation can contribute to an increase in brain sphingomyelin species with implications for age effects and regulation of brain development. Effects of lithium highlight novel anti-neuroinflammatory treatment pathways. Both 24-hydroxycholesterol and eicosadienoic acid may be used as biomarkers in ALS thereby possibly helping to manage the progressive stages of disease. / Libyan Government

No / Bioactive lipid mediators derived from polyunsaturated fatty acids (PUFA) and exhibit a range of tissue and cell-specific activities in many physiological and pathological processes. Electrospray tandem mass spectrometry coupled to liquid chromatography (LC/ESI-MS/MS) is a sensitive, versatile analytical methodology for the qualitative and quantitative analysis of lipid mediators. Here we present an LC/ESI-MS/MS assay for the simultaneous analysis of twenty mono- and poly-hydroxy fatty acid derivatives of linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids. The assay was linear over the concentration range 1-100 pg/¿L, whilst the limits of detection and quantitation were 10-20 and 20-50 pg respectively. The recovery of the extraction methodology varied from 76-122% depending on the metabolite. This system is useful for profiling a range of biochemically-related potent mediators including the newly discovered resolvins and protectins, and their precursor hydroxy-eicosapentaenoic and hydroxy-docosahexaenoic acids, and, consequently, advance our understanding of the role of PUFA in health and disease. / Wellcome Trust, British Heart Foundation

Cytochrom P450 (CYP)-Enzyme hydroxylieren und epoxydieren Arachidonsäure (AA) zu bioaktiven Metaboliten wie 20-Hydroxyeicosatetraensäure (20-HETE) und Epoxyeicosatriensäuren (EETs). Diese CYP-abhängigen Eicosanoide fungieren als Mediatoren bei der Regulation der Gefäß-, Nieren- und Herzfunktion. Hauptziel der vorliegenden Arbeit war es, die Identität der 20-HETE bildenden CYP-Isoformen in der Mausniere aufzuklären. Ein weiterer Schwerpunkt war die Bestimmung von Veränderungen im Metabolismus CYP-abhängiger Eicosanoide in Tiermodellen des akuten Nieren- und Herzversagens. Zur Identifizierung der 20-HETE bildenden CYP-Isoform wurde die Substrat- und Wirkungsspezifität von Cyp4a10, Cyp4a12a, Cyp4a12b und Cyp4a14, sowie ihre geschlechts- und stammspezifische Expression charakterisiert. Die Ergebnisse dieser Arbeit zeigen, dass Cyp4a12a die 20-HETE Synthase der Mausniere ist. Cyp4a12a wird durch Androgene induziert und seine Expressionshöhe ist für geschlechts- und stammspezifische Unterschiede in der 20-HETE Bildung verantwortlich. Im Rattenmodell des Ischämie/Reperfusions (I/R)-induzierten Nierenschadens wird eine 20-HETE Freisetzung durch I/R induziert. Wir konnten zeigen, dass der I/R-Schaden durch Hemmung der 20-HETE Bildung signifikant reduziert wird. Im Rattenmodell der Herzinsuffizienz (SHHF) ist das Herzversagen mit einer Variante des EPHX2 Gens assoziiert. EPHX2 kodiert für die lösliche Epoxidhydrolase (sEH), die den Abbau von EETs katalysiert. Wir konnten zeigen, dass die Genvariation zu signifikant höheren sEH-Aktivitäten im Herzen (3-fachen) und in der Niere (30-fachen) führt, im Vergleich zu Rattenstämmen, die keine Herzinsuffizienz entwickeln. Die vorliegende Arbeit unterstreicht die pathophysiologische Bedeutung von Veränderungen im Metabolismus von 20-HETE und EETs. Daher erscheint es vielversprechend, den CYP-Eicosanoid Stoffwechsel als neuen Angriffspunkt für die pharmakologische Behandlung kardiovaskulärer Erkrankungen zu erschließen. / Cytochrome P450 (CYP) enzymes hydroxylate and epoxidize arachidonic acid (AA) to bioactive metabolites such as 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs). These CYP-dependent eicosanoids serve as mediators in the regulation of vascular, renal and cardiac function. The main objective of the present study was to identify the 20-HETE producing CYP isoforms in the mouse kidney. Another focus was to determine changes in the metabolism of CYP-dependent eicosanoids in animal models of acute renal and heart failure. To identify the 20-HETE producing CYP-isoform the substrate and reaction specificity of Cyp4a10, Cyp4a12a, Cyp4a12b and Cyp4a14, as well as their sex- and strain-specific expression were characterized. The present study shows that Cyp4a12a is the predominant AA hydroxylase in the mouse kidney. Cyp4a12a is induced by androgens and its expression determines the sex and strain-specific differences in 20-HETE generation. In a rat model of renal ischemia/reperfusion (I/R) injury, I/R triggered the release of 20-HETE and we were able to ameliorate renal injury by pharmacological inhibition of 20-HETE production. In a rat model of heart failure (spontaneously hypertensive heart failure rats, SHHF) the heart failure phenotype is associated with a variant of the EPHX2 gene. EPHX2 is coding for the soluble epoxide hydrolase (sEH) which catalyze the degradation of EETs. We found that the gene variation leads to significantly higher sEH activities in the heart (3-fold) and in the kidney (30-fold) compared to rat strains not prone to the development of heart failure. The present study emphasizes the pathophysiological relevance of changes in the biosynthesis and degradation of 20-HETE and EETs. Therefore, it appears promising to develop the CYP-eicosanoid pathway as a novel clinical target for the treatment of cardiovascular diseases.

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.

Human skin has distinct lipid metabolism and production of bioactive lipid mediators that can be modulated by nutritional supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFA), of which eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids exert anti-inflammatory effects. The aims of this project were to gain better understanding of their individual mechanisms in human epidermis and dermis. HaCaT keratinocytes, 46BR.1N fibroblasts, primary human epidermal keratinocytes and dermal fibroblasts were treated with EPA or DHA for 72h and then sham-irradiated or exposed to 15 mJ/cm2 ultraviolet radiation (UVR). Viability was measured by the MTT assay. The expression of cyclooxygenase-2 (COX-2), microsomal prostaglandin synthase-1 (mPGES-1) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) proteins was explored by western blotting. Human skin explants (n=4 donors) were cultured for 3 or 6 days and supplemented with EPA, DHA or vehicle. Culture media were collected to evaluate tissue damage and PUFA cytotoxicity (lactate dehydrogenase assay). Epidermal and dermal lipid profiles were assessed by gas chromatography and liquid chromatography coupled to tandem mass spectrometry. Primary keratinocytes were treated with fatty acids and various lipid mediators for 48h. Their effect was determined by the scratch assay and transepithelial electrical resistance. UVR upregulated COX-2 in HaCaT and primary epidermal keratinocytes, but did not affect mPGES-1 and 15-PGDH protein expression. UVR upregulated COX-2 and mPGES-1 in 46BR.1N fibroblasts but had no effect on 15-PGDH expression. The same UVR dose did not alter the expression of COX-2, mPGES-1 and 15-PGDH in primary dermal fibroblasts. Only EPA attenuated COX-2 expression in HaCaT and primary keratinocytes and either EPA or DHA had any effect in 46BR.1N and primary fibroblasts. Skin explants showed initial post-biopsy tissue damage. EPA and DHA supplementation augmented cellular levels of the corresponding fatty acids in both epidermis and dermis to a different extent. Increased uptake of DHA in the dermis was accompanied by reduced arachidonic acid levels. EPA treatment stimulated the production of PGE3 and various HEPE in epidermis, while DHA treatment caused high levels of HDHA species in dermis. N-3 PUFA and their derivatives delayed wound healing, cell migration and epidermal barrier permeability, while n-6 PUFA lipids showed the opposite effect. Overall, these findings suggest that EPA and DHA differently affect skin cells and skin, with EPA preference in epidermis and DHA in the dermis. These results highlight the importance of differential skin responses that could be important in skin health and disease.

I. DESCRIPTION DE PROJET DE RECHERCHE<p><p>Le canal sodium épithélial bloquable par l’amiloride (ENaC) est une protéine intégrale de la membrane apicale des épithéliums impliqués dans l’absorption du sodium. Deux fonctions majeures sont directement liées au fonctionnement d’ENaC. D’une part, la régulation de la balance sodée par le rein et donc de la pression artérielle et d’autre part, la clairance du fluide alvéolaire pulmonaire.<p>Le transport vectoriel de sel et d’eau à travers ces épithéliums à jonctions serrées repose sur un transport actif de sodium entraînant un flux osmotique d’eau. Ce transport de sodium s’effectue en deux étapes: l’entrée apicale, par diffusion, facilitée via ENaC, et la sortie basolatérale, active, par les pompes Na+/K+ ATPases.<p><p>Ces dernières années, un intérêt grandissant est porté sur les acides gras polyinsaturés à longues chaînes de type oméga 3 (PUFAs) et leurs implications dans divers processus physiologiques. Entre autres effets, les PUFAs modulent différents types de canaux ioniques (canaux Na+ dépendant du voltage, Ca++ L-type, K+).<p>Les études in vivo impliquant un effet à long terme des PUFAs décrivent des mécanismes inhibiteurs. Cependant, lors d’une étude précédente, axée sur la composition lipidique des membranes de cellules rénales en culture et l’influence de l’ajout d’acides gras saturés et insaturés sur le transport du sodium, nous avons constaté que les acides gras polyinsaturés à longues chaînes de type oméga 3 augmentaient la réabsorption du sodium. Ces résultats pourraient être intéressants, car les canaux sodiques de l’épithélium alvéolaire sont en contact direct avec le surfactant, dont la composition lipidique varie en fonction de l’apport alimentaire en PUFAs. Chez les prématurés humains, le syndrome de détresse respiratoire est une des causes les plus fréquentes de mortalité. Dans un certain nombre de cas, on peut restaurer une fonction pulmonaire satisfaisante par l’administration de surfactant.<p><p>Dans ce travail, nous avons opté pour une approche fondamentale des mécanismes de régulation du canal sodium épithélial par l’acide eicosapentanoïque (EPA, C 20:5, n-3). Des études électrophysiologiques, biochimiques et d’imagerie cellulaire ont été réalisées sur la lignée cellulaire A6 de rein d’amphibien, qui sert d’épithélium modèle pour l’étude d’ENaC depuis plus de 25 ans. Cette lignée exprime des canaux sodiques très sélectifs et possède des propriétés électrophysiologiques facilitant l’étude de leur régulation.<p><p>Ce travail nous a permis de mettre en évidence de nouveaux mécanismes fondamentaux dont la pertinence physiologique et /ou clinique ne pourra être établie qu’en transposant cette étude sur un modèle in vivo, comme nous le proposons dans les perspectives.<p><p>Dans le présent travail, nous avons étudié :<p><p>1.\ / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished