Fatty acid amide hydrolase (FAAH) is a widely conserved amidase in eukaryotes, best known for inactivating the signal of N-acylethanolamine (NAE) lipid mediators. In the plant Arabidopsis thaliana, FAAH-mediated hydrolysis of NAEs has been associated with numerous biological processes. Recently, the phylogenetic distribution of FAAH into two major branches (group I and II FAAHs) across angiosperms outside of Arabidopsis (and in other Brassicaceae), suggests a previously unrecognized complexity of this enzyme. Although A. thaliana has long been used to assess biological questions for plants, in this case it will fall short in understanding the significance of multiple FAAHs in other plant systems. Thus, in this study, I examined the role (s) of six FAAH isoforms in upland cotton (Gossypium hirsutum L.) and two FAAHs in the legume Medicago truncatula.

Les maladies métaboliques, comme le diabète, la dyslipidémie ou l’obésité, constituent un problème majeur de santé publique dans les pays développés. Ces maladies très répandues restent encore difficiles à traiter malgré une recherche active. Les stratégies thérapeutiques contre ces maladies incluent le développement de nouvelles molécules ciblant les récepteurs aux acides gras, étant donné leur rôle essentiel dans l’homéostasie du métabolisme. C’est dans ce contexte que s’inscrit ce travail portant sur deux récepteurs couplés aux protéines G, les récepteurs aux acides gras à courte chaîne 2 et 3 ou free fatty acid receptors 2 (FFA2) et 3 (FFA3). Nous avons tout d'abord cherché à déterminer le profil d'expression des deux récepteurs. Ensuite, nous avons établi des lignées cellulaires stable exprimant FFA2 ou FFA3 afin d’étudier la pharmacologie d’agonistes synthétiques et endogènes de ces récepteurs. Après avoir identifié les voies de signalisation engendrées par l’activation des récepteurs, nous avons démontré que les agonistes synthétiques étaient des activateurs allostériques, c’est-à-dire qu’ils se liaient aux récepteurs sur un site distinct de celui des ligands endogènes. Pour identifier les résidus d’acides aminés nécessaires à la reconnaissance des ligands, nous avons généré une gamme de mutants ponctuels de ces récepteurs par mutagénèse dirigée. En analysant l’effet des mutations dans des tests fonctionnels, nous avons pu déterminer avec précision où se liaient les ligands et ainsi pu dessiner par informatique des modèles structuraux des récepteurs qui pourront être utilisés pour le drug design de futures molécules agonistes de ces récepteurs. / Metabolic diseases, such as diabetes, dyslipidemia or obesity, are more and more weighing on public health expenses in developed countries. Despite active research, these widespread diseases remain difficult to handle. Promising new therapeutic strategies against metabolic diseases include the development of drugs targeting the free fatty acid receptors, as key players in metabolism homeostasis. In this context, the current PhD thesis focuses on the study of two G protein-coupled receptors, namely the short-chain free fatty acid receptors 2 (FFA2) and 3 (FFA3). First, we investigated the expression of the two receptors of interest in a variety of cell types. Then, in order to study the pharmacology and the binding mode of endogenous and synthetic agonists on FFA2 and FFA3, we established stable cell lines expressing each receptor. Once we identified the signaling pathways engendered in response to receptor activation, we showed that synthetic agonists were allosteric activators of the receptors, in the sense that they bind to the receptors at a distinct site from short-chain fatty acids, i.e. the endogenous agonists. To identify the aminoacid residues that were involved in ligand binding, we generated a variety of point mutated receptors by site-directed mutagenesis. By analyzing the effects of the mutations in functional tests, we determined precisely the aminoacid residues that were essential for ligand binding. From these results, we designed in silico structural models which may aid future drug design efforts for the discovery of new FFA2 and FFA3 agonists.

L’athérosclérose est étroitement liée au diabète de type 2. De fortes concentrations plasmatiques en acides gras libres (AGL) et en insuline sont des caractéristiques retrouvées chez les patients souffrant de ces deux pathologies. Les AGL, présents dans notre alimentation, font partie de l’environnement auquel les cellules sont exposées. Leurs effets dépendent de leur nature, les acides gras saturés (AGS) étant néfastes et les acides gras monoinsaturés (AGMI) plus protecteurs. Ils ont donc des effets variés sur les cellules musculaires lisses vasculaires (CMLV) impliquées dans la pathogénèse de l’athérosclérose. Ainsi, l’objectif principal de ce projet de maîtrise était d’évaluer l’impact de deux combinaisons d’AGL sur la viabilité des CMLV, en condition hyperinsulinémique ou non. Les deux combinaisons renfermaient les mêmes AGL mais en proportions différentes, l’une étant plus riche en AGS et l’autre en AGMI. Nos résultats ont montré que les combinaisons d’AGL ont un effet pro-apoptotique principalement dû aux AGS. L’acide oléique présent dans les combinaisons atténue cependant cet effet. Il diminue même plus fortement l’apoptose des CMLV lorsqu’associé à un AGS que lorsqu’utilisé seul. Cet impact est significatif uniquement dans certaines proportions de ces AGL et est plus efficace en présence d’insuline. Ces résultats mettent en lumière la présence d’une compétition entre mécanismes anti- et pro-apoptotiques en fonction des proportions d’AGS versus AGMI et de l’insulinémie chez les CMLV. Ils soulignent également l’importance de la présence des AGMI dans les diètes riches en AGS et pourraient être utiles pour l’élaboration de nouvelles diètes adaptées aux patients athérosclérotiques et diabétiques. / Atherosclerosis is closely linked to type 2 diabetes. High plasmatic concentrations of free fatty acids (FFA) and insulin are common features in patients suffering from both diseases. FFA, present in our diet, are part of the environment to which body cells are exposed. Their effects are dependent of their nature, being harmful for saturated fatty acids (SFA) and more protective for monounsaturated fatty acids (MUFA). They can have therefore various effects on vascular smooth muscle cells (VSMC) implicated throughout the development of atherosclerosis. Thus, this study aimed to assess the impact of two FFA combinations on VSMC viability, whether or not in a hyperinsulinemic condition. Both combinations contained the same FFA but in different proportions, one being richer in SFA and the other in MUFA. Our results showed that FFA combinations have a pro-apoptotic impact, mainly due to SFA. However, the presence of oleic acid in the combinations attenuated this effect. Furthermore, oleic acid had the capacity to reduce more strongly VSMC apoptosis when combined with a SFA than when used alone, although only under specific FFA ratios. This impact is even more effective in presence of insulin. These results highlight the presence of a competition between anti- and pro-apoptotic mechanisms dependent of FFA ratios (SFA vs. MUFA) and insulinemia to which are exposed VSMC. They also underline the importance of the presence of MUFA such as oleic acid in diets rich in SFA and could be useful for the development of new diets adapted to atherosclerotic and diabetic patients.

A reposição de glicogênio pós treino foi investigada usando uma mistura de ambos, glicose e glicose-frutose, como repositores, em atletas corredores de longa distância. Dez corredores competitivos (30±4,7 anos) foram avaliados para composição corporal e consumo alimentar antes do exercício de 90 minutos em esteira elétrica a 70% V02máx. Amostras de sangue venoso foram coletadas antes e após o término do exercício, quando eles receberam 1g de carboidrato.kg-1 de uma mistura de ambos, glicose-frutose (CHO1) e glicose (CHO2), e outra com sucralose ou placebo (controle). Amostras de sangue foram retiradas 30, 60, 90 e 120 minutos após o consumo dos suplementos e usadas para determinação de glicose e de ácidos graxos plasmáticos, por reações colorimétricas. Não foram observadas diferenças significativas na composição corporal e na hidratação durante o exercício. Os tratamentos CHO1 e CHO2 produziram elevação na glicemia, em 30 minutos, comparados ao grupo placebo. Entretanto, em 90 min, somente no tratamento CHO1, uma queda na glicemia foi observada (CHO2>CHO1). Os ácidos graxos livres aumentaram comparativamente após o exercício (CHO1=CHO2=placebo) e, diferente do placebo, em 90 minutos, reduziram nos tratamentos CHO1 e CHO2. Ambos os repositores atuaram similarmente nas concentrações de ácidos graxos livres, mas o declínio da glicose plasmática (remoção da glicose) ocorreu primeiramente com o tratamento glicose-frutose do que com o glicose. Assim, a mistura glicose-frutose parece promover uma reposição de glicogênio mais rápida após exercícios de longa duração. / The post training glycogen replacement was investigated using either glucose or glucose-fructose mixture as repositors in long-distance athletes. Ten males (30±4,7yrs) voluntary competitive long distance runners were assessed for body composition and dietary intake prior to a 90 min 70% vo2 max exercise in treadmill. Blood samples were collected before and after the exercise when they received orally 1g of CHO.kg-1 either as maltodextrin-glucose-fructose (CHO1) or maltodextrin - glucose (CHO2) mixtures, having sucralose or placebo (control). Blood samples were drawn 30,60, 90 and 120 minutes after supplement intake and used for plasma glucose and free-fatty acids determinations by colorimetric reactions. There were no significant changes on body composition, mass or hydration, during the treadmill exercise. CHO1 and CHO2 loading increased the 30 min blood glucose both significatively above the placebo. However at 90 min only CHO1 decreased significantily (CHO2>CHO1). The FFA increased comparatively (CHO1=CHO2=placebo) after exercise and differently from placebo CHO1 and CHO2 decreased (similarly) up to 90 min. Both energetic repositors acted similarly on FFA levels but the plasma glucose decreasing (glucose removal) occurred earlier with glucose-fructose loading rather than glucose alone. Thus glucose-fructose mixtures seems to promote faster glycogen repletion after long lasting aerobic exercises.

In der vorliegenden Arbeit wurde eine Beeinflussung der Aktivität der humanen neutrophilen Elastase (EC 3.4.21.37) durch wässrige und Dichlormethan-Extrakte von 15 Basidiomyceten festgestellt. Durch aktivitätsgeleitete Fraktionierung (mehrfache SC, GC-MS) der Dichlormethan-Extrakte von Heterobasidion annosum (Fr.) Bref. und Lactarius deterrimus Grög. wurden Fraktionen freier langkettiger Fettsäuren als ein wirksames Prinzip der Elastase-Hemmung und auch der Kollagenase-Hemmung (Clostridium histolyticum Kollagenase, EC 3.4.24.3) isoliert und identifiziert. Das Screening von 17 freien langkettigen Fettsäuren zeigte, dass einfach ungesättigte Fettsäuren eine stärkere Hemmung der Elastase-Aktivität bewirkten als ihre gesättigten bzw. mehrfach ungesättigten Homologa: Ölsäure (C18:1 cis-9): IC50 5µM; Stearin-(C18:0), Linolsäure (C18:2 cis-9,12): IC50 10µM; alpha- (C18:3 cis-9,12,15), gamma-Linolensäure (C18:3 cis-6,9,12): IC50 15µM. Inhibitorisch am stärksten wirksam war Erucasäur! e (C22:1 cis-13): IC50 450nM. Für Kollagenase wurde hingegen gezeigt, dass die gesättigten Fettsäuren eine erheblich stärkere Hemmaktivität als ihre ungesättigten Homologa aufwiesen. Aktivste Verbindungen waren Palmitin- (C16:0), Heptadecan- (C17:0), Stearin- und Nonadecansäure (C19:0) mit IC50-Werten von 20-45µM. Die Untersuchung von 9 ausgewählten Fettsäuren bezüglich der Hemmung der Aktivität der MMP-9 (EC 3.4.24.35) zeigte als aktivste Verbindungen Palmitolein- (16:1 cis-9), alpha- und gamma-Linolensäure. Die wirksamen Konzentrationen (250µM) lagen jedoch sehr hoch. Zytotoxizitätsuntersuchungen (ECV-304) der Extrakte von H. annosum und L. deterrimus sowie der freien Fettsäuren schlossen sich ebenso wie Untersuchungen zur Proteaseaktivität der Zelllinien ECV-304, MCF-7 und MDA-MB 231 an. Die Proteaseaktivität der Zellen nahm in der Reihenfolge ECV-304 < MCF-7 < MDA-MB 231 zu. Die einzig untersuchte Fettsäure gamma-Linolensäure zeigte keine reproduzierbare Beeinflussung d! er Proteaseaktivität. / In the present paper it was established that the activity of humane neutrophil elastase (EC 3.4.21.37) is affected by aqueous and dichloromethane extracts of 15 basidiomycetes. Bioassay-guided fractionation (repeated CC, GC-MS) of dichloromethane extracts of Heterobasidion annosum (Fr.) Bref. and Lactarius deterrimus Grög. led to isolation and identification of fractions of free fatty acids as one active principle of elastase inhibition as well as collagenase inhibition (Clostridium histolyticum collagenase, EC 3.4.24.3). By testing 17 free fatty acids for elastase inhibition it was shown that the inhibition rate of unsaturated acids was much higher than the rate of the saturated ones: oleic acid (C18:1 cis-9): IC50 5µM; stearic acid (C18:0), linoleic acid (C18:2 cis-9,12): IC50 10µM; linolenic acid (C18:3 cis-9,12,15), gamma-linolenic acid (C18:3 cis-6,9,12): IC50 15µM. The highly active erucic acid with an IC50 value of 450nM is remarkable. As a result for collagenase we can assume that the saturated fatty acids were more potent than the unsaturated ones. Palmitic acid (C16:0), heptadecanoic acid (C17:0), stearic acid, and nonadecanoic acid (C19:0) were the most potent fatty acids with IC50 values of 20-45µM. 9 selected fatty acids were investigated for their ability to inhibit the activity of MMP-9 (EC 3.4.24.35). Palmitoleic acid (16:1 cis-9), linolenic acid, and gamma-linolenic acid were the most potent fatty acids but their inhibiting concentrations were very high (250µM). Investigation of cytotoxicity of the extracts of H. annosum, L. deterrimus, and free fatty acids as well as investigation of protease activity of ECV-304, MCF-7, and MDA-MB 231 cells followed. Protease activity of cells increased in the following manner: ECV-304 < MCF-7 < MDA-MB 231. The only investigated fatty acid gamma-linolenic acid did not influence protease activity reproducibly.

A reposição de glicogênio pós treino foi investigada usando uma mistura de ambos, glicose e glicose-frutose, como repositores, em atletas corredores de longa distância. Dez corredores competitivos (30±4,7 anos) foram avaliados para composição corporal e consumo alimentar antes do exercício de 90 minutos em esteira elétrica a 70% V02máx. Amostras de sangue venoso foram coletadas antes e após o término do exercício, quando eles receberam 1g de carboidrato.kg-1 de uma mistura de ambos, glicose-frutose (CHO1) e glicose (CHO2), e outra com sucralose ou placebo (controle). Amostras de sangue foram retiradas 30, 60, 90 e 120 minutos após o consumo dos suplementos e usadas para determinação de glicose e de ácidos graxos plasmáticos, por reações colorimétricas. Não foram observadas diferenças significativas na composição corporal e na hidratação durante o exercício. Os tratamentos CHO1 e CHO2 produziram elevação na glicemia, em 30 minutos, comparados ao grupo placebo. Entretanto, em 90 min, somente no tratamento CHO1, uma queda na glicemia foi observada (CHO2>CHO1). Os ácidos graxos livres aumentaram comparativamente após o exercício (CHO1=CHO2=placebo) e, diferente do placebo, em 90 minutos, reduziram nos tratamentos CHO1 e CHO2. Ambos os repositores atuaram similarmente nas concentrações de ácidos graxos livres, mas o declínio da glicose plasmática (remoção da glicose) ocorreu primeiramente com o tratamento glicose-frutose do que com o glicose. Assim, a mistura glicose-frutose parece promover uma reposição de glicogênio mais rápida após exercícios de longa duração. / The post training glycogen replacement was investigated using either glucose or glucose-fructose mixture as repositors in long-distance athletes. Ten males (30±4,7yrs) voluntary competitive long distance runners were assessed for body composition and dietary intake prior to a 90 min 70% vo2 max exercise in treadmill. Blood samples were collected before and after the exercise when they received orally 1g of CHO.kg-1 either as maltodextrin-glucose-fructose (CHO1) or maltodextrin - glucose (CHO2) mixtures, having sucralose or placebo (control). Blood samples were drawn 30,60, 90 and 120 minutes after supplement intake and used for plasma glucose and free-fatty acids determinations by colorimetric reactions. There were no significant changes on body composition, mass or hydration, during the treadmill exercise. CHO1 and CHO2 loading increased the 30 min blood glucose both significatively above the placebo. However at 90 min only CHO1 decreased significantily (CHO2>CHO1). The FFA increased comparatively (CHO1=CHO2=placebo) after exercise and differently from placebo CHO1 and CHO2 decreased (similarly) up to 90 min. Both energetic repositors acted similarly on FFA levels but the plasma glucose decreasing (glucose removal) occurred earlier with glucose-fructose loading rather than glucose alone. Thus glucose-fructose mixtures seems to promote faster glycogen repletion after long lasting aerobic exercises.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2017-08-11T14:43:57Z No. of bitstreams: 2 Andriele Magarinos Focking 2017.pdf: 2481446 bytes, checksum: 763f767d058face92edaaa394dc5b780 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-11T14:43:57Z (GMT). No. of bitstreams: 2 Andriele Magarinos Focking 2017.pdf: 2481446 bytes, checksum: 763f767d058face92edaaa394dc5b780 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-09 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The utilization of biodiesel as a substitute for diesel oil is one of the alternatives that aims to minimize the utilization of non-renewable fuels (petroleum) in the world energy matrix. Worldwide, biodiesel production occurs through the transesterification process. In Brazil, the most commonly used raw material for this purpose is soybean oil. A new way that has been promising for the biodiesel production is the Hidroesterification process. With that, the present work a imed to evaluate the soy oil enzymatic hydrolysis, using the comercial enzyme Lipozyme TL IM as the catalyst of the reaction. Was performed hydrolysis test of soy oil in closed and batch system, based on two experimental plannings (Placket-Burmann ad DCCR), to evaluate the effects of the variables involved in the process(pH; temperature; molar fraction water/oil; stirrings peed of the batch reactor and mass fraction enzyme/substrate). Since that, was perfomed kinetic studies with different conditions of molar fraction water/oil and different dosages of catalyst, as well as the utilization of a tip ultrasonic and a chemical agent to evaluateit’s effects on the kinetic of the reaction. To describe the kinetic of enzymatic hydrolysis of soy oil, was used a mathematical model based on the Michaelis-Menten kinetic. The results of experimental planningsindicatedthattheaciditylevelswerefavoredwhenthetemperatureof 52,2ºC, pH 6.1, stirring speed 150 rpm and molar fraction water/oil 37,7:1, getting 82,4% in the value of acidity level. The kinetic studies showed that the utilization of the probe ultrasonic did not accelerated the velocity of the enzymatic hydrolysis reaction. The kinetic involving the utilization of the chemical agent suffered a high decrease in the velocity of reaction, showing that this would be a inhibitor of enzymatic activity of Lipozyme TL IM. By the mathematical model, was verified that the model described well the experimental datas, as well made able the visualization of others components concentration (triacylglycerols, diacylglycerols, monoacylglycerols, glycerol, free fatty acids and water). It is believed that the values of the constants of the reaction velocity obtained in the model has more physical meaning and could be used to conducting the simulations in anothers conditions. / A utilização do biodiesel como substituto do óleo diesel é uma das alternativas que visa minimizar a utilização de combustíveis não renováveis (petróleo) na matriz energética mundial.Mundialmente, a produção de biodiesel ocorre pelo processo de transesterificação. No Brasil, a matéria-prima mais utilizada para esta finalidade é o óleo de soja. Uma nova rota que se mostra promissora para a produção de biodiesel é o processo de hidroesterificação. Desta maneira, o presente trabalho objetivou avaliar a hidrólise enzimática do óleo de soja, utilizando a enzima comercial Lipozyme TL IM como catalisador da reação. Foram realizados ensaios de hidrólise do óleo de soja em sistema fechado e batelada, baseados em dois planejamentos experimentais (Placket-Burmann e DCCR), visando avaliar os efeitos das variáveis envolvidas no processo (pH; temperatura; razão molar água/óleo; velocidade de agitação no reator batelada e razão mássica enzima/substrato). A partir disto, foram realizados estudos cinéticos com diferentes condições de razão molar água/óleo e diferentes dosagens de catalisador, bem como a utilização de ultrassom de ponta e um agente químico visando avaliar seus efeitos na cinética da reação. Para descrever a cinética da hidrólise enzimática do óleo de soja foi utilizado um modelo matemático baseado na cinética de Michaelis-Menten. Os resultados dos planejamentos experimentais indicaram que o índice de acidez foi favorecido quando temperatura de 52,2ºC, pH 6,1, velocidade de agitação de 150 rpm e razão molar água/óleo 37,7:1, obtendo 82,4% no valor do índice de acidez. Os estudos cinéticos demonstraram que a utilização do ultrassom de sonda não acelerou a velocidade da reação de hidrólise 13 enzimática. A cinética envolvendo a utilização de agente químico sofreu um alto decaimento na velocidade da reação, demonstrando que este seria um inibidor da atividade enzimática da Lipozyme TL IM. Pela modelagem matemática verificou-se que o modelo descreveu bem os dados experimentais, bem como possibilitou a visualização da concentração dos demais componentes (triacilgliceróis, diacilgliceróis, monoacilgliceróis, glicerol,ácidos graxos livreeágua). Acredita-se que os valores das constantes da velocidade de reação obtidos no modelo tenham maior significado físico e possam ser utilizados para realização de simulações em outras condições.

Chronic hyperlipidemia (lipotoxicity) and hyperglycemia (glucotoxicity) have recently been shown to induce Endoplasmic Reticulum (ER) stress, which may contribute to pancreatic beta-cell dysfunction in type 2 diabetes. This thesis examined the involvement of ER stress in beta-cell lipotoxicity and glucotoxicity. Although chronic treatment with saturated free fatty acids (FFA) in vitro induced ER stress, altering ER stress by increasing or knocking-down GRP78 chaperone expression had no effect on apoptosis induction. Conversely, overexpression of ER chaperones rescued the reduction in proinsulin protein levels caused by chronic exposure to high glucose, although it had no effect on the decreased insulin mRNA levels and proinsulin translation rate. Thus, ER stress is likely not the main mechanism involved in saturated FFA-induced beta-cell apoptosis in vitro, but it may contribute to glucotoxic effects on proinsulin levels. These findings have increased our understanding of the link between ER stress and beta-cell dysfunction in type 2 diabetes.

Chronic hyperlipidemia (lipotoxicity) and hyperglycemia (glucotoxicity) have recently been shown to induce Endoplasmic Reticulum (ER) stress, which may contribute to pancreatic beta-cell dysfunction in type 2 diabetes. This thesis examined the involvement of ER stress in beta-cell lipotoxicity and glucotoxicity. Although chronic treatment with saturated free fatty acids (FFA) in vitro induced ER stress, altering ER stress by increasing or knocking-down GRP78 chaperone expression had no effect on apoptosis induction. Conversely, overexpression of ER chaperones rescued the reduction in proinsulin protein levels caused by chronic exposure to high glucose, although it had no effect on the decreased insulin mRNA levels and proinsulin translation rate. Thus, ER stress is likely not the main mechanism involved in saturated FFA-induced beta-cell apoptosis in vitro, but it may contribute to glucotoxic effects on proinsulin levels. These findings have increased our understanding of the link between ER stress and beta-cell dysfunction in type 2 diabetes.

L’athérosclérose est étroitement liée au diabète de type 2. De fortes concentrations plasmatiques en acides gras libres (AGL) et en insuline sont des caractéristiques retrouvées chez les patients souffrant de ces deux pathologies. Les AGL, présents dans notre alimentation, font partie de l’environnement auquel les cellules sont exposées. Leurs effets dépendent de leur nature, les acides gras saturés (AGS) étant néfastes et les acides gras monoinsaturés (AGMI) plus protecteurs. Ils ont donc des effets variés sur les cellules musculaires lisses vasculaires (CMLV) impliquées dans la pathogénèse de l’athérosclérose. Ainsi, l’objectif principal de ce projet de maîtrise était d’évaluer l’impact de deux combinaisons d’AGL sur la viabilité des CMLV, en condition hyperinsulinémique ou non. Les deux combinaisons renfermaient les mêmes AGL mais en proportions différentes, l’une étant plus riche en AGS et l’autre en AGMI. Nos résultats ont montré que les combinaisons d’AGL ont un effet pro-apoptotique principalement dû aux AGS. L’acide oléique présent dans les combinaisons atténue cependant cet effet. Il diminue même plus fortement l’apoptose des CMLV lorsqu’associé à un AGS que lorsqu’utilisé seul. Cet impact est significatif uniquement dans certaines proportions de ces AGL et est plus efficace en présence d’insuline. Ces résultats mettent en lumière la présence d’une compétition entre mécanismes anti- et pro-apoptotiques en fonction des proportions d’AGS versus AGMI et de l’insulinémie chez les CMLV. Ils soulignent également l’importance de la présence des AGMI dans les diètes riches en AGS et pourraient être utiles pour l’élaboration de nouvelles diètes adaptées aux patients athérosclérotiques et diabétiques. / Atherosclerosis is closely linked to type 2 diabetes. High plasmatic concentrations of free fatty acids (FFA) and insulin are common features in patients suffering from both diseases. FFA, present in our diet, are part of the environment to which body cells are exposed. Their effects are dependent of their nature, being harmful for saturated fatty acids (SFA) and more protective for monounsaturated fatty acids (MUFA). They can have therefore various effects on vascular smooth muscle cells (VSMC) implicated throughout the development of atherosclerosis. Thus, this study aimed to assess the impact of two FFA combinations on VSMC viability, whether or not in a hyperinsulinemic condition. Both combinations contained the same FFA but in different proportions, one being richer in SFA and the other in MUFA. Our results showed that FFA combinations have a pro-apoptotic impact, mainly due to SFA. However, the presence of oleic acid in the combinations attenuated this effect. Furthermore, oleic acid had the capacity to reduce more strongly VSMC apoptosis when combined with a SFA than when used alone, although only under specific FFA ratios. This impact is even more effective in presence of insulin. These results highlight the presence of a competition between anti- and pro-apoptotic mechanisms dependent of FFA ratios (SFA vs. MUFA) and insulinemia to which are exposed VSMC. They also underline the importance of the presence of MUFA such as oleic acid in diets rich in SFA and could be useful for the development of new diets adapted to atherosclerotic and diabetic patients.