17 research outputs found
Nanoencapsulation of EPA:DHA 6:1 potentiates the endothelium-dependent relaxation of coronary artery rings compared to native form: role of NO, endothelium-dependent hyperpolarization and prostanoids
No full textIntroduction The omega 3 polyunsaturated fatty acid (PUFAs) formulation containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with a 6:1 ratio is a potent inducer of endothelium-dependent nitric oxide (NO)-mediated vasorelaxation that also improves ageing-related and angiotensin II-induced endothelial dysfunction in rats. Purpose Since PUFAs are unstable, the possibility that nanoencapsulation of EPA:DHA 6:1 followed by coating potentiates the bioactivity was evaluated. Methods EPA:DHA 6:1 was emulsified in water phase and coated with proteins and gum derivatives or used in native form. Changes in isometric tension of porcine coronary artery rings were determined using organ chambers. The role of NO was assessed using Nw-nitro-L-arginine (L-NA, NO synthase inhibitor), prostanoids using indomethacin (Indo, COX inhibitor) and endothelium-derived hyperpolarization (EDH) using TRAM-34 and UCL-1684 (Ca2 + -dependent potassium channel inhibitors). Results Coated EPA:DHA 6:1 nanoparticles (NP) caused in a concentration-dependent manner endothelium-dependent relaxations that were more sustained than those of the native form. At 0.3%, coated and native forms induced 56.6 ± 2.8% and 51.1 ± 1.5%relaxations at 10 min, and 93.8 ± 2.1% and 35.1 ± 1.7% at 60 min, respectively. The response to the coated EPA:DHA 6:1 NP was inhibited by L-NA and not affected by Indo, TRAM-34 plus UCL-1684, and by the previous incubation of rings with another oil (corn oil 0.3%). In contrast, L-NA, Indo, and TRAM-34 plus UCL-1684 inhibited the relaxation to EPA:DHA 6:1. Conclusion Nanoencapsulation of EPA:DHA 6:1 followed by coating perpetuated their ability to cause endothelium-dependent relaxation of coronary artery rings that is exclusively mediated by NO. In contrast, the relaxing activity of the native form involved NO, EDH and vasorelaxant prostanoids. Therefore, coated EPA:DHA 6:1 NP appear to be an attractive approach to enhance the vasoprotective effect of omega 3 PUFAs
Nanoencapsulation of EPA:DHA 6:1 potentiates the endothelium-dependent relaxation of coronary artery rings compared to native form: role of NO, endothelium-dependent hyperpolarization and prostanoids
No full textIntroduction The omega 3 polyunsaturated fatty acid (PUFAs) formulation containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with a 6:1 ratio is a potent inducer of endothelium-dependent nitric oxide (NO)-mediated vasorelaxation that also improves ageing-related and angiotensin II-induced endothelial dysfunction in rats. Purpose Since PUFAs are unstable, the possibility that nanoencapsulation of EPA:DHA 6:1 followed by coating potentiates the bioactivity was evaluated. Methods EPA:DHA 6:1 was emulsified in water phase and coated with proteins and gum derivatives or used in native form. Changes in isometric tension of porcine coronary artery rings were determined using organ chambers. The role of NO was assessed using Nw-nitro-L-arginine (L-NA, NO synthase inhibitor), prostanoids using indomethacin (Indo, COX inhibitor) and endothelium-derived hyperpolarization (EDH) using TRAM-34 and UCL-1684 (Ca2 + -dependent potassium channel inhibitors). Results Coated EPA:DHA 6:1 nanoparticles (NP) caused in a concentration-dependent manner endothelium-dependent relaxations that were more sustained than those of the native form. At 0.3%, coated and native forms induced 56.6 ± 2.8% and 51.1 ± 1.5%relaxations at 10 min, and 93.8 ± 2.1% and 35.1 ± 1.7% at 60 min, respectively. The response to the coated EPA:DHA 6:1 NP was inhibited by L-NA and not affected by Indo, TRAM-34 plus UCL-1684, and by the previous incubation of rings with another oil (corn oil 0.3%). In contrast, L-NA, Indo, and TRAM-34 plus UCL-1684 inhibited the relaxation to EPA:DHA 6:1. Conclusion Nanoencapsulation of EPA:DHA 6:1 followed by coating perpetuated their ability to cause endothelium-dependent relaxation of coronary artery rings that is exclusively mediated by NO. In contrast, the relaxing activity of the native form involved NO, EDH and vasorelaxant prostanoids. Therefore, coated EPA:DHA 6:1 NP appear to be an attractive approach to enhance the vasoprotective effect of omega 3 PUFAs
Empagliflozin treatment does not affect the hypertensive response to Ang II administration to rats but decreases oxidative stress in the arterial wall, and endothelial and cardiac dysfunction
No full textBackground Selective sodium-glucose cotransporter 2 (SGLT2) inhibitors have shown cardiovascular protection in type 2 diabetes patients with established cardiovascular disease independently of glycemic control. Angiotensin II (Ang II) and H2O2 have been shown to be strong inducers of the expression of SGLT2 and 1 in endothelial cells promoting oxidative stress and endothelial dysfunction. Purpose This study examined the cardiovascular protective effect of empagliflozin (empa) in a normoglycemic experimental model of hypertension in the rat. Methods Male Wistar rats received empa (30 mg/kg/day) provided in the diet for 5 weeks. After 1 week, rats underwent sham surgery (sham rats) or surgery with implantation of an osmotic mini-pump infusing Ang II (0.4 mg/kg/d) for 4 weeks. Systolic blood pressure (SBP) was assessed by sphygmomanometry, the cardiac function using echocardiography, the expression level of target proteins by immunofluorescence staining, and the level of oxidative stress using dihydroethidium staining. Results Angiotensin II administration increased systolic blood pressure from about 130 to 180 mmHg, which was not affected by the empa treatment. The 4-week Ang II treatment did not significantly affect the systolic cardiac function (cardiac output, left ventricle ejection fraction) but impaired the diastolic function as indicated by a reduced E' and IVRT values, and an increased E/E' value. The Ang II treatment increased significantly the heart and right ventricle weight whereas the left ventricle + septum weight was slightly but not significantly increased. No such functional and structural changes were observed in the Ang II + empa treatment group. An increased immunofluorescence eNOS signal in the endothelium, and a higher level of ROS throughout the aorta wall were observed in the Ang II-treated group, both of which were significantly reduced in the empa + Ang II-treated group. In the Ang II-treated group, the high level of oxidative stress in the aorta was significantly reduced by the AT1 receptor antagonist losartan, the NADPH oxidase inhibitor VAS-2871, the eNOS inhibitor NG-nitro-L-arginine and also to a greater extent by the selective SGLT2 inhibitor empa compared to the dual SGLT1/2 inhibitor sotagliflozin. Conclusion(s) The present findings indicate that although the empa treatment did not affect the hypertensive response of rats to Ang II, the SGLT2 inhibitor prevented the deleterious impact of Ang II on the diastolic cardiac function and remodeling, and the upregulation of eNOS expression and oxidative stress in the aorta wall. Thus, these findings highlight the protective potential of empa on the cardiovascular system in a normoglycemic hypertensive experimental model.
Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Boehringer Ingelheim Pharma GmbH & Co KG (Biberach an der Riss, Germany
Cardiac diastolic dysfunction in angiotensin II treated hypertensive rats is associated with endothelial upregulation of SGLT1/2 in the macro and microcirculation: Protective effect of empagliflozin
No full textBackground: /Introduction: The angiotensin II (Ang II)/AT1R/NADPH oxidase-prooxidant pathway has been shown to upregulate the expression of SGLT1 and 2 and to induce premature endothelial dysfunction in coronary endothelial cells. Since all these effects are prevented by the dual SGLT1/2 inhibitor sotagliflozin (sota) and the SGLT2 inhibitor empagliflozin (empa), SGLT1 and 2 are involved in the induction of endothelial dysfunction.
Purpose: The aim of the study was to evaluate the role of SGLT1 and 2 in the Ang II-induced hypertensive response leading to cardiac and vascular endothelial dysfunction.
Methods: Male Wistar rats received empa (30 mg/kg/day) provided in the diet for 5 weeks. After 1 week, rats underwent sham surgery (sham rats) or surgery with implantation of an osmotic mini-pump infusing Ang II (0.4 mg/kg/d) for 4 weeks. Systolic blood pressure (SBP) was assessed by plethysmography, the cardiac function using echocardiography, the expression level of target proteins by immunofluorescence staining, fibrosis by Sirius red staining, the function of SGLT1 and 2 indirectly by the uptake of glucose-conjugated anthocyanins, and the level of oxidative stress using dihydroethidium staining.
Results: The administration of Ang II to rats caused an increased systolic blood pressure from about 140 to 180 mmHg, which was not affected by empa. In the heart, the hypertensive response resulted in an increased left ventricle mass and a diastolic dysfunction as indicated by an elevated E/e' and a decreased IVRT, fibrosis and increased collagen I and ANP expression levels. In the secondary branch of the mesenteric artery, it resulted in an increased level of oxidative stress, AT1R, collagen I and of endothelial ACE, VCAM-1, MCP-1, MMP-2, MMP-9 associated with a down-regulation of eNOS. It was also associated with an increased endothelial expression level of SGLT1 in the aorta, mesenteric resistance vessel and coronary microcirculation. Moreover, an increased uptake of anthocyanins is observed in the aorta predominantly in the endothelium and this effect is markedly reduced by sota and empa. All of the above parameters were markedly reduced in the Ang II plus empa group whereas the empa treatment alone had little effect compared to the control group.
Conclusion: The findings indicate that Ang II-induced hypertension promoting left ventricle cardiac dysfunction, and both macro and microvascular endothelial dysfunction are associated with an up-regulation of SGLT1 and 2 in endothelial cells. They further indicate that empa prevents the noxious impact of Ang II on the heart and vasculature despite persistent hypertension
Potential of fluorescent nano-carriers targeting VCAM-1 for early detection of senescent endothelial cells
No full textIntroduction
Endothelial senescence has been identified as an early event promoting the development of endothelial dysfunction (ED), a hallmark of vascular ageing and major cardiovascular diseases. In vivo, senescent endothelial cells (EC) appear initially at arterial sites at risk characterized by disturbed flow and low shear stress (i.e., bifurcations and curvatures) compared to those at low risk characterized by laminar flow and a high level of shear stress (i.e., aorta).
Objective
The aim is to develop fluorescent nano-carriers (NC) to target a cell surface protein up-regulated in senescent ECs, for diagnostic purposes.
Method
NC with a lipid core containing a fluorescent probe (NR668 or Cy5.5 derivative) stabilized by a polymer scaffold and decorated with VCAM-1 antibodies (NC-VCAM-1) were applied to different models of EC senescence in cultured porcine coronary artery (premature senescence induced by angiotensin II and replicative senescence observed at passage P3). The fluorescence signal was visualized by confocal microscopy.
Results
Both models of EC senescence demonstrated higher levels of senescence-associated beta-galactosidase activity, senescence markers and VCAM-1 than healthy EC at P1. Incubation of either P3 EC or Ang II-treated P1 EC with fluorescent NC-VCAM-1 showed a higher level of fluorescence than P1 EC. The EC-related NC-VCAM-1 fluorescent signal is abolished by the previous incubation of EC with an antibody directed against VCAM-1, demonstrating the ability to target cell surface VCAM-1. The highest level of NC-VCAM-1 fluorescence was observed with NC with an average diameter below 100 nm and at 37 °C.
Conclusion
The present findings indicate that fluorescent NC-VCAM-1 allow the detection of senescent EC. Thus, using fluorescent functionalized NC targeting a senescence-associated cell surface protein appears to be an attractive strategy to evaluate the burden of EC senescence, which promotes ED and, ultimately, cardiovascular events
Potential of fluorescent nano-carriers targeting VCAM-1 for early detection of senescent endothelial cells
No full textIntroduction
Endothelial senescence has been identified as an early event promoting the development of endothelial dysfunction (ED), a hallmark of vascular ageing and major cardiovascular diseases. In vivo, senescent endothelial cells (EC) appear initially at arterial sites at risk characterized by disturbed flow and low shear stress (i.e., bifurcations and curvatures) compared to those at low risk characterized by laminar flow and a high level of shear stress (i.e., aorta).
Objective
The aim is to develop fluorescent nano-carriers (NC) to target a cell surface protein up-regulated in senescent ECs, for diagnostic purposes.
Method
NC with a lipid core containing a fluorescent probe (NR668 or Cy5.5 derivative) stabilized by a polymer scaffold and decorated with VCAM-1 antibodies (NC-VCAM-1) were applied to different models of EC senescence in cultured porcine coronary artery (premature senescence induced by angiotensin II and replicative senescence observed at passage P3). The fluorescence signal was visualized by confocal microscopy.
Results
Both models of EC senescence demonstrated higher levels of senescence-associated beta-galactosidase activity, senescence markers and VCAM-1 than healthy EC at P1. Incubation of either P3 EC or Ang II-treated P1 EC with fluorescent NC-VCAM-1 showed a higher level of fluorescence than P1 EC. The EC-related NC-VCAM-1 fluorescent signal is abolished by the previous incubation of EC with an antibody directed against VCAM-1, demonstrating the ability to target cell surface VCAM-1. The highest level of NC-VCAM-1 fluorescence was observed with NC with an average diameter below 100 nm and at 37 °C.
Conclusion
The present findings indicate that fluorescent NC-VCAM-1 allow the detection of senescent EC. Thus, using fluorescent functionalized NC targeting a senescence-associated cell surface protein appears to be an attractive strategy to evaluate the burden of EC senescence, which promotes ED and, ultimately, cardiovascular events
Ciblage des cellules endothéliales sénescentes à l’aide d’une approche théranostique : potentiel thérapeutique d’une formulation d’Oméga 3
No full textThe endothelium, the cell monolayer lining the luminal surface of blood vessels, has as a pivotal role in the control of vascular homeostasis. Strategically located, endothelial cells can regulate diverse vascular responses including vascular tone, platelet aggregation, thrombosis, leukocyte trafficking, inflammation and angiogenesis. In major types of cardiovascular disease, an endothelial dysfunction is observed initially that is characterized by an imbalance between the vasodilator mechanisms and the induction of endothelium-derived contracting factors, resulting in impaired endothelium-dependent vasodilatation. Several epidemiological or interventional studies have shown that consumption of the major omega-3 PUFAs, namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been related to a reduced risk of morbidity/mortality due to CVDs. Due to the presence of multiple unsaturation, omega-3 PUFAs are prone to degradation which can result in the production of various reactive chemical species leading to loss of functionality. Therefore, the present study investigated whether nanoencapsulation of EPA:DHA 6:1 is able to improve the stability of omega-3 PUFAs and hence, to enhance their beneficial effect at the endothelial function using in vitro, ex vivo and in vivo approaches, and, if so, to determine the underlying mechanisms. EPA:DHA 6:1 was emulsified in water phase and coated with proteins and gum derivatives or used in native form. Firstly, vascular reactivity studies were performed on left circumflex porcine coronary artery rings and changes in isometric tension were determined using organ chambers. Secondly, NO formation was assessed in cultured porcine coronary artery endothelial cells using the fluorescent probe DAF-FM and confocal microscopy. The antiaggregatory effect of endothelial cells was assessed using suspensions of washed human platelets incubated in an aggregometer. Thirdly, for the in vivo study, middle-aged male Wistar rats received by daily gavage 100 mg/kg of either native EPA:DHA 6:1 form or coated EPA:DHA 6:1 nanoparticles or water (control). After 1-week of treatment, the animals were euthanized. The main mesenteric artery and thoracic aorta were used for vascular reactivity studies, and the thoracic aorta for immunofluorescence studies on frozen section. The addition of coated EPA:DHA 6:1 nanoparticles to U46619-pre-contracted coronary artery rings induced concentration-dependent relaxations in rings with intact endothelium that were more sustained than those of the native EPA:DHA 6:1 form, whereas small relaxations were observed in denuded rings. The sustained endothelium-dependent relaxation to the coated EPA:DHA 6:1 nanoparticles was abolished by an eNOS inhibitor (L-NA) indicating the exclusive involvement of NO. In contrast, the relaxation in response to the native form was significantly reduced by indomethacin indicating the involvement of vasorelaxant prostanoids.L’endothélium, la monocouche cellulaire tapissant la surface luminale des vaisseaux sanguins, est un organe central dans la régulation de l’homéostasie vasculaire. En effet, les cellules endothéliales ont un rôle clé dans le maintien du tonus vasculaire et dans la protection contre la thrombose et le remodelage vasculaire, principalement grâce à la formation et libération de puissants facteurs vasoprotecteurs tels que le monoxyde d’azote (NO) et l’hyperpolarisation dépendante de l’endothélium (EDH). De nombreuses études épidémiologiques ou d’intervention ont montré que la consommation alimentaire des acides gras oméga-3 PUFAs majeurs, à savoir l’acide eicosapentaénoïque (EPA) et l’acide docosahexaénoïque (DHA), a aussi été associée à une réduction de la morbi-mortalité cardiovasculaire. En raison de la présence de multiples insaturations, les oméga-3 sont sujets à une dégradation qui peut entraîner la production de diverses espèces chimiques réactives conduisant à une perte de fonctionnalité. Par conséquent, la présente étude a examiné si la nanoencapsulation d'EPA:DHA 6:1 suivie d'un enrobage avec de la gomme est capable d'améliorer la stabilité des oméga-3 PUFAs et, par conséquent, d'améliorer leur effet bénéfique sur la fonction endothéliale en utilisant une approche in vitro, ex vivo et in vivo, et si oui, pour déterminer les mécanismes sous-jacents. EPA:DHA 6:1 est émulsionné en phase aqueuse et enrobé de protéines et de dérivés de gomme ou utilisé sous forme native.Tout d'abord, des études de réactivité vasculaire sont réalisées sur des anneaux d'artère coronaire porcine. Deuxièmement, la formation de NO est évaluée dans des cellules endothéliales cultivées d'artère coronaire porcine en utilisant la sonde fluorescente DAF-FM et la microscopie confocale. Troisièmement, pour l'étude in vivo, des rats Wistar mâles d’âge moyen ont reçu quotidiennement pendant 1 semaine par gavage 100 mg/kg soit de la forme native d’EPA:DHA 6:1, soit de la forme nanoencapsulée d’EPA : DHA 6:1, soit de l'eau (contrôle). Après une semaine de traitement, les rats sont euthanasiés. L'artère mésentérique principale et l'aorte thoracique sont utilisées pour les études de réactivité vasculaire, et l'aorte thoracique pour les études d'immunofluorescence sur coupes congelées. L'ajout de nanoformulation d’EPA:DHA 6:1 à des anneaux d'artère coronaire pré contractés avec l’U46619 a induit des relaxations dépendantes de la concentration dans les anneaux ayant un endothélium intact qui étaient plus importantes et soutenues que celles de la forme native, alors que seulement de faibles relaxations ont été observées dans les anneaux dénudés d’endothélium. La relaxation soutenue dépendante de l'endothélium induite par la nanoformulation d'EPA:DHA 6:1 a été abolie par un inhibiteur de la eNOS (L-NA) indiquant l'implication exclusive de NO. En revanche, la relaxation en réponse à la forme native est significativement réduite par l'indométacine indiquant l'implication des prostaglandines vasorelaxantes
Ciblage des cellules endothéliales sénescentes à l’aide d’une approche théranostique : potentiel thérapeutique d’une formulation d’Oméga 3
No full textL’endothélium, la monocouche cellulaire tapissant la surface luminale des vaisseaux sanguins, est un organe central dans la régulation de l’homéostasie vasculaire. En effet, les cellules endothéliales ont un rôle clé dans le maintien du tonus vasculaire et dans la protection contre la thrombose et le remodelage vasculaire, principalement grâce à la formation et libération de puissants facteurs vasoprotecteurs tels que le monoxyde d’azote (NO) et l’hyperpolarisation dépendante de l’endothélium (EDH). De nombreuses études épidémiologiques ou d’intervention ont montré que la consommation alimentaire des acides gras oméga-3 PUFAs majeurs, à savoir l’acide eicosapentaénoïque (EPA) et l’acide docosahexaénoïque (DHA), a aussi été associée à une réduction de la morbi-mortalité cardiovasculaire. En raison de la présence de multiples insaturations, les oméga-3 sont sujets à une dégradation qui peut entraîner la production de diverses espèces chimiques réactives conduisant à une perte de fonctionnalité. Par conséquent, la présente étude a examiné si la nanoencapsulation d'EPA:DHA 6:1 suivie d'un enrobage avec de la gomme est capable d'améliorer la stabilité des oméga-3 PUFAs et, par conséquent, d'améliorer leur effet bénéfique sur la fonction endothéliale en utilisant une approche in vitro, ex vivo et in vivo, et si oui, pour déterminer les mécanismes sous-jacents. EPA:DHA 6:1 est émulsionné en phase aqueuse et enrobé de protéines et de dérivés de gomme ou utilisé sous forme native.Tout d'abord, des études de réactivité vasculaire sont réalisées sur des anneaux d'artère coronaire porcine. Deuxièmement, la formation de NO est évaluée dans des cellules endothéliales cultivées d'artère coronaire porcine en utilisant la sonde fluorescente DAF-FM et la microscopie confocale. Troisièmement, pour l'étude in vivo, des rats Wistar mâles d’âge moyen ont reçu quotidiennement pendant 1 semaine par gavage 100 mg/kg soit de la forme native d’EPA:DHA 6:1, soit de la forme nanoencapsulée d’EPA : DHA 6:1, soit de l'eau (contrôle). Après une semaine de traitement, les rats sont euthanasiés. L'artère mésentérique principale et l'aorte thoracique sont utilisées pour les études de réactivité vasculaire, et l'aorte thoracique pour les études d'immunofluorescence sur coupes congelées. L'ajout de nanoformulation d’EPA:DHA 6:1 à des anneaux d'artère coronaire pré contractés avec l’U46619 a induit des relaxations dépendantes de la concentration dans les anneaux ayant un endothélium intact qui étaient plus importantes et soutenues que celles de la forme native, alors que seulement de faibles relaxations ont été observées dans les anneaux dénudés d’endothélium. La relaxation soutenue dépendante de l'endothélium induite par la nanoformulation d'EPA:DHA 6:1 a été abolie par un inhibiteur de la eNOS (L-NA) indiquant l'implication exclusive de NO. En revanche, la relaxation en réponse à la forme native est significativement réduite par l'indométacine indiquant l'implication des prostaglandines vasorelaxantes.The endothelium, the cell monolayer lining the luminal surface of blood vessels, has as a pivotal role in the control of vascular homeostasis. Strategically located, endothelial cells can regulate diverse vascular responses including vascular tone, platelet aggregation, thrombosis, leukocyte trafficking, inflammation and angiogenesis. In major types of cardiovascular disease, an endothelial dysfunction is observed initially that is characterized by an imbalance between the vasodilator mechanisms and the induction of endothelium-derived contracting factors, resulting in impaired endothelium-dependent vasodilatation. Several epidemiological or interventional studies have shown that consumption of the major omega-3 PUFAs, namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been related to a reduced risk of morbidity/mortality due to CVDs. Due to the presence of multiple unsaturation, omega-3 PUFAs are prone to degradation which can result in the production of various reactive chemical species leading to loss of functionality. Therefore, the present study investigated whether nanoencapsulation of EPA:DHA 6:1 is able to improve the stability of omega-3 PUFAs and hence, to enhance their beneficial effect at the endothelial function using in vitro, ex vivo and in vivo approaches, and, if so, to determine the underlying mechanisms. EPA:DHA 6:1 was emulsified in water phase and coated with proteins and gum derivatives or used in native form. Firstly, vascular reactivity studies were performed on left circumflex porcine coronary artery rings and changes in isometric tension were determined using organ chambers. Secondly, NO formation was assessed in cultured porcine coronary artery endothelial cells using the fluorescent probe DAF-FM and confocal microscopy. The antiaggregatory effect of endothelial cells was assessed using suspensions of washed human platelets incubated in an aggregometer. Thirdly, for the in vivo study, middle-aged male Wistar rats received by daily gavage 100 mg/kg of either native EPA:DHA 6:1 form or coated EPA:DHA 6:1 nanoparticles or water (control). After 1-week of treatment, the animals were euthanized. The main mesenteric artery and thoracic aorta were used for vascular reactivity studies, and the thoracic aorta for immunofluorescence studies on frozen section. The addition of coated EPA:DHA 6:1 nanoparticles to U46619-pre-contracted coronary artery rings induced concentration-dependent relaxations in rings with intact endothelium that were more sustained than those of the native EPA:DHA 6:1 form, whereas small relaxations were observed in denuded rings. The sustained endothelium-dependent relaxation to the coated EPA:DHA 6:1 nanoparticles was abolished by an eNOS inhibitor (L-NA) indicating the exclusive involvement of NO. In contrast, the relaxation in response to the native form was significantly reduced by indomethacin indicating the involvement of vasorelaxant prostanoids
P6278 - Ageing is associated with increased endothelial sodium-glucose cotransporter 1 expression at arterial sites at risk promoting enhanced anthocyanin accumulation and improved vascular oxidative stress
No full textIntroduction
Ageing is characterized by endothelial dysfunction and vascular oxidative stress affecting initially arterial sites at risk. Anthocyanin-rich products are potent stimulators of the endothelial formation of nitric oxide. Sodium-glucose co-transporter 1 (SGLT1) expression has been shown to be increased by oxidative stress and mediate anthocyanin uptake in endothelial cells.
Purpose
The study determined whether ageing is associated with an upregulation of SGLT1 in arterio-susceptible (aortic arch) and resistant (aorta) sites, and evaluated the vascular SGLT1-mediated anthocyanin uptake. In addition, the impact of a 2-week ingestion of an anthocyanin-rich blackcurrant concentrate (ARBC) by old rats on vascular anthocyanin uptake and oxidative stress, and systolic blood pressure (SBP) was assessed.
Methods
Male Wistar rats (22-month old) were either untreated or treated with ARBC (60 and 120 mg/kg/day) in the drinking water for 2 weeks. SGLT1 expression was assessed by immunofluorescence, anthocyanin accumulation by Neu A reagent using a purified extract (BCE) prepared from ARBC, oxidative stress by dihydroethidium using confocal microscopy, and SBP by tail-cuff sphingomanometry.
Results
SGLT1 immunofluorescence was observed predominantly in the endothelium and was higher in the aortic arch than the aorta in old rats whereas only low levels were observed in young rats (12-week old). Exposure of vascular sections to BCE resulted in anthocyanin uptake exclusively in the endothelium, which was higher in the aortic arch than the aorta, and more pronounced in old than young rats. Anthocyanin uptake induced by BCE in the aorta was markedly reduced by LX4211 (a SGLT1/2 inhibitor) both in old and young rats. A high level of oxidative stress was observed throughout the aortic wall of old compared to young rats, which was inhibited by LX4211. Ingestion of ARBC by old rats resulted in a dose-dependent accumulation of anthocyanins throughout the aorta wall and the aortic arch. The tissue accumulation of anthocyanins was associated with a reduced level of oxidative stress. Ageing was associated with increased SBP by about 8 mmHg, which was reduced by ARBC 60 and 120 mg/kg/day treatment by about 5 and 7 mmHg, respectively.
Conclusion
The present findings indicate that ageing is associated with an upregulation of SGLT1 predominantly in the endothelium and that this effect is more pronounced at the aortic arch than the aorta. The increased endothelial expression level of SGLT1 promoted a greater accumulation of anthocyanins sensitive to LX4211. In addition, a 2-week ingestion of ARBC by old rats resulted in the accumulation of anthocyanins throughout the arterial wall of the aortic arch and aorta, and resulted in a reduced level of oxidative stress and systolic blood pressure. Thus, SGLT1 may be an attractive target to restore vascular protection at arterial sites at risk by promoting endothelial and vascular uptake of anthocyanins
Anthocyanin-rich blackcurrant intake by old rats improves blood pressure, vascular oxidative stress and endothelial dysfunction associated with SGLT1- and 2-mediated vascular uptake of anthocyanin
No full textIntroduction Aging-related endothelial dysfunction and vascular oxidative stress affect early arterial sites at risk. Anthocyanins uptake via sodium-glucose co-transporter 1 (SGLT1) are potent inducers of endothelial formation of nitric oxide (NO). Aims This study examined if anthocyanin-rich blackcurrant (ARB) improves the endothelial function in old rats. Method Male Wistar rats (22-month old) received ARB (60 and 120 mg/kg/d) orally for 2 weeks. Systolic blood pressure (SBP) was assessed by tail-cuff sphygmomanometry, vascular reactivity using organ chambers, protein expression by immunofluorescence, oxidative stress using dihydroethidium, and anthocyanin uptake by Neu reagent. Results Old rats showed increased SBP, abolished endothelium-dependent hyperpolarization-mediated relaxation and increased contractile response to phenylephrine in the mesenteric artery, which were improved by ARB. Old aorta showed increased oxidative stress and expression levels of eNOS, which were improved by ARB. SGLT1 immunofluorescence predominantly in the endothelium was more pronounced in the aortic arch than the aorta and higher in old than young rats, whereas the SGLT2 signal was low. The ARB treatment induced a dose-dependent accumulation of anthocyanins in the aorta and aortic arch. An ARB purified extract promoted ex vivo greater anthocyanins uptake mostly in the endothelium in the aortic arch than aorta, and in old compared to young rats. The anthocyanins uptake was inhibited to a greater extent by a dual SGLT1/2 inhibitor than by a selective SGLT2 inhibitor in the aorta of young and old rats. Both SGLT inhibitors reduced also ex vivo the age-related vascular oxidative stress. Conclusion The upregulation of SGLT1, and the greater SGLT1 and SGLT2-mediated uptake of anthocyanins predominantly in the endothelium at arterial sites at risk in old rats suggest that anthocyanins appear as interesting natural products to protect the endothelial function with increasing age
