Introduction Non-nutritive sweeteners are mainly consumed by overweight or obese individuals (Sylvetsky and Rother, 2016). An increased risk of cardiovascular mortality has been identified among sweetener consumers (Malik et al., 2019). Furthermore, sweetener consumption, in the context of weight gain, has been linked to an increased incidence of type 2 diabetes and cardiovascular events (Azad et al., 2017; Pepino et al., 2015). Objective Our aim was to evaluate the impact of chronic acesulfame potassium (AceK) consumption on vascular reactivity and adipose tissue function in a mouse model of diet-induced obesity. Method Mice were fed a high-fat high-sugar diet for 8 weeks, followed by 8 additional weeks of a high-fat diet combined with either water or AceK. Vascular reactivity was assessed ex vivo by wire myography on isolated mesenteric artery rings in response to phenylephrine, acetylcholine, and sodium nitroprusside. Pharmacological inhibitors (indomethacin, LNNA, tram34 and apamin) were used to investigate vasoactive pathways. Gene expression of inflammatory and metabolic markers was analyzed by quantitative PCR in adipose tissue, complemented by histological analysis. Results Chronic AceK consumption in the context of obesity resulted in an enhanced vasoconstrictor response to phenylephrine, characterized by an increased maximal response (Fig. 1). In parallel, both endothelium-dependent and endothelium-independent vasodilation were impaired. These vascular alterations were associated with changes in adipose tissue gene expression and morphological features consistent with adipose tissue remodeling. Conclusion These findings demonstrate that chronic AceK intake promotes vascular dysfunction in obese mice and is associated with alterations in adipose tissue. They highlight a potential link between non-nutritive sweetener consumption, metabolic dysregulation, and cardiovascular risk in obesity.

Non-nutritive sweeteners (NNS) such as sucralose are widely consumed, particularly by obese individuals, yet their long-term tissue accumulation and biological effects remain controversial. Early pharmacokinetic studies suggested minimal absorption and rapid excretion, but recent evidence challenges this view. This study investigates sucralose bioaccumulation in adipose tissue and its consequences for inflammation in lean and obese mice. Two independent cohorts of male C57BL/6J mice were used for short-term (14 days) and long-term (12 weeks) sucralose exposure protocols, respectively. The short-term cohort received daily oral gavage of water or sucralose (185 mg kg-1 day-1) under normal chow feeding. The long-term cohort was fed standard chow or a high-fat diet (HFD) with drinking water with or without sucralose (15 mg kg-1 day-1). Sucralose concentrations were quantified by LC-MS/MS in plasma and epididymal adipose tissue. Plasma and adipose inflammation markers were evaluated by multiplex assay and real-time PCR, respectively. Sucralose detection was observed in plasma and eWAT, but at low concentrations, after both short-term and long-term exposure, with reduced adipose tissue inflammation specifically in HFD mice under chronic exposure. In vitro, sucralose exposure did not consistently modulate basal or TNFα-induced expression of key inflammatory genes (Il6, Tnf, and Mcp1) in 3T3-L1 adipocytes or RAW 264.7 macrophages. Although adipose sucralose accumulation did not trigger inflammation and even slightly reduced inflammatory gene expression in HFD mice, its long-term metabolic consequences remain unknown. Given that adipose tissue plays a central role in cardiometabolic regulation, the potential bioaccumulation of sucralose warrants a precautionary approach and calls for further research to investigate potential effects on adipose function and broader metabolic responses.

Introduction Artificial sweeteners such as sucralose are increasingly used as a substitute to sugar to preserve sweetness with no calories associated. However, growing evidence raises concern about their metabolic and cardiovascular safety. Preliminary ex vivo data from our group showed that chronic sucralose consumption in mice modulates vascular reactivity. Moreover, the NutriNet cohort recently highlighted an increased risk of ischemic vascular diseases among chronic sucralose consumers. Objective To evaluate: 1. the impact of chronic sucralose consumption, as a substitute for sucrose, on vascular function in vivo during ischemia-reperfusion stress in healthy and obese mice; 2. the role of oxidative stress and inflammation to explain the potential vascular alterations. Method C57bl6J mice (n=15 per group) were fed ad libitum with a standard or high-fat diet combined with water, sucrose (10%) or sucralose (0.017%) for 12 weeks. The day of sacrifice, the mice underwent 1.5hours of hind limb ischemia followed by 2hours of reperfusion. Femoral blood flow was continuously assessed by laser speckle contrast imaging. In the first subset, femoral vascular reactivity was measured immediately after reperfusion and vascular permeability was estimated from muscle edema. In a second subset, the mice were sacrificed after reperfusion for assessment of oxidative stress in the femoral artery using DHE staining (10μM) and measure of plasmatic inflammation markers. Results Following IR, sucrose consumption impaired vascular function compared with water, particularly in obese mice as shown by reduced endothelium-dependent vasorelaxation and increased vascular permeability. Sucralose consumption also decreased endothelium-dependent relaxation regardless of diet, with an increased vascular permeability in obese mice. In the sucralose-fed obese group, these alterations were associated with oxidative stress in the femoral artery, and increased expression of vascular adhesion molecules, such as CX3CL1 and VCAM. Conclusion The main finding of this study shows that sucralose, as a replacement for sucrose, does not reduce the vascular damage observed following ischemia-reperfusion. More specifically, for sucralose consumption increased vascular oxidative stress appears to play a key role, potentially linked to increased immune cell adhesion. Further studies are needed to elucidate the involvement of the CX3CL1-CX3CR1 signaling pathway.

Introduction Our previous data revealed that endothelial dysfunction observed in response to hyperglycemia was partially mediated by increased O-GlcNAcylation. Yet, the activation of endothelial nitric oxide synthase (eNOS), a key enzyme regulating endothelial function, is mainly dependent on its phosphorylation at specific serine residues, which are also key targets of O-GlcNAcylation. Although studies explored the interplay between eNOS phosphorylation and O-GlcNAcylation, none investigated the impact of altering this balance on endothelial function. Objective To evaluate the impact of modulating the balance between eNOS phosphorylation and O-GlcNAcylation on endothelial function. Method To modulate O-GlcNAcylation, isolated rat aorta and cultured endothelial cells (HUVECs) were incubated with high glucose (33mM) or specific inhibitors of O-GlcNAcylation enzymes: Thiamet-G (O-GlcNAcase inhibitor, 0.1μM) or OSMI-2 (O-GlcNAc transferase inhibitor, 50μM). Tissues were also stimulated with insulin (0.1μM) to promote phosphorylation and explore the interplay with O-GlcNAcylation. Western Blot analysis was performed to assess eNOS O-GlcNAcylation and phosphorylation. Endothelial function was evaluated by vascular reactivity in aortic rings and NO production was quantified in tissues and endothelial cells. Results Our preliminary data showed that hyperglycemia (HG) increases protein O-GlcNAcylation, which is associated with impaired vasorelaxation in response to acetylcholine. Interestingly, treatment with Thiamet-G, which increases O-GlcNAcylation, also impaired endothelial function. Consistent with these findings, the use of OSMI-2 reversed the alteration induced by HG, emphasizing the critical role of O-GlcNAcylation in vascular dysfunction. This effect seems mediated by the interplay between O-GlcNAcylation and eNOS phosphorylation. In HUVECs, Thiamet-G-induced O-GlcNAcylation reduced eNOS phosphorylation, while OSMI-2 decreased O-GlcNAcylation and increased phosphorylation of this enzyme. Conclusion These data suggest that an imbalance between O-GlcNAcylation and phosphorylation of eNOS may contribute to vascular endothelial dysfunction. Further experiments are in progress to better understand the impact of eNOS O-GlcNAcylation in modulating vascular function under stress conditions, which is highly dependent on phosphorylation mechanisms.

Background: TOTUM-854 is a patented plant extract blend characterized by its components that have previously been described for their potential health benefits in limiting hypertension onset. However, most of the literature data remain descriptive regarding the mode of action at the cellular level, especially in humans, and further investigations are required for optimized therapeutic strategies. Methods: We first demonstrated in an L-NAME mouse model that TOTUM-854 supports the prevention of hypertension in vitro and in vivo. Then, we designed an ex vivo clinical innovative approach considering the circulating metabolites produced by the digestive tract upon TOTUM-854 ingestion in humans. Human serum was collected in healthy volunteers before and after the acute intake of 3.71 g of TOTUM-854. The bioavailability of circulating metabolites was confirmed and characterized by UPLC-MS. Human serum containing TOTUM-854-derived metabolites was further processed for incubation with human endothelial cells (HUVECs), in the absence or presence of palmitate (200 µM). Results: HUVEC protection against lipotoxicity was characterized by (1) decreased ACE-1 activity (−32% p < 0.0001); (2) the inhibition of oxidative stress with decreased ROS (−12% observed by DCFDA and DHE fluorescent microscopy) and decreased Nox2 gene expression (−6.7 fold change vs. palmitate, p < 0.01); and (3) the inhibition of an inflammatory response, with a decrease in IL-1β release (−37% compared to palmitate, p < 0.001) and decreased MCP-1 and VCAM-1 gene expression (−93% p < 0.001 and −77% p < 0.001, respectively). Conclusions: Overall, this study provides insightful data regarding the protective role of TOTUM-854 in human endothelial cells. Using an innovative clinical ex vivo approach, our data support the role of TOTUM-854 circulating metabolites in vascular protection in humans.

Hyperglycemia increases the heart sensitivity to ischemia-reperfusion (IR), but the underlying cellular mechanisms remain unclear. Mitochondrial dynamics (the processes that govern mitochondrial morphology and their interactions with other organelles, such as the reticulum), has emerged as a key factor in the heart vulnerability to IR. However, it is unknown whether mitochondrial dynamics contributes to hyperglycemia deleterious effect during IR. We hypothesized that (i) the higher heart vulnerability to IR in hyperglycemic conditions could be explained by hyperglycemia effect on the complex interplay between mitochondrial dynamics, Ca2+ homeostasis, and reactive oxygen species (ROS) production; and (ii) the activation of DRP1, a key regulator of mitochondrial dynamics, could play a central role. Using transmission electron microscopy and proteomic analysis, we showed that the interactions between sarcoplasmic reticulum and mitochondria and mitochondrial fission were increased during IR in isolated rat hearts perfused with a hyperglycemic buffer compared with hearts perfused with a normoglycemic buffer. In isolated mitochondria and cardiomyocytes, hyperglycemia increased mitochondrial ROS production and Ca2+ uptake. This was associated with higher RyR2 instability. These results could contribute to explain the early mPTP activation in mitochondria from isolated hearts perfused with a hyperglycemic buffer and in hearts from streptozotocin-treated rats (to increase the blood glucose). DRP1 inhibition by Mdivi-1 during the hyperglycemic phase and before IR induction, normalized Ca2+ homeostasis, ROS production, mPTP activation, and reduced the heart sensitivity to IR in streptozotocin-treated rats. In conclusion, hyperglycemia-dependent DRP1 activation results in higher reticulum-mitochondria calcium exchange that contribute to the higher heart vulnerability to IR.

Mitochondrial fission is a key trigger of cardiac ischemia-reperfusion injuries (IR). Exercise training is an efficient cardioprotective strategy, but its impact on mitochondrial fragmentation during IR remains unknown. Using isolated rat hearts, we found that exercise training limited the activation of dynamin-like protein 1 and limited mitochondrial fragmentation during IR. These results support the hypothesis that exercise training contributes to cardioprotection through its capacity to modulate the mitochondrial fragmentation during IR.

HomeArteriosclerosis, Thrombosis, and Vascular BiologyAhead of PrintSMIT1 Expression in Arterial Tissue: A Potential New Trigger of Vascular Dysfunctions and ROS Production in Rats No AccessLetterRequest AccessAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessLetterRequest AccessSMIT1 Expression in Arterial Tissue: A Potential New Trigger of Vascular Dysfunctions and ROS Production in Rats Antoine Grandperrin, Eva Strock, Léna Petit, Sydney Risdon, Doria Boulghobra, Sandrine Gayrard, Cyril Reboul, Guillaume Walther, Sylvain Battault and Gregory Meyer Antoine GrandperrinAntoine Grandperrin UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Eva StrockEva Strock UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Léna PetitLéna Petit https://orcid.org/0000-0003-1315-5821 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Sydney RisdonSydney Risdon UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Doria BoulghobraDoria Boulghobra UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Sandrine GayrardSandrine Gayrard https://orcid.org/0009-0008-4103-4182 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Cyril ReboulCyril Reboul https://orcid.org/0000-0001-5181-3827 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Guillaume WaltherGuillaume Walther https://orcid.org/0000-0001-7604-8973 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. , Sylvain BattaultSylvain Battault https://orcid.org/0000-0003-2934-2314 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. and Gregory MeyerGregory Meyer Correspondence to: Gregory Meyer, UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, F-84000 Avignon, France. Email E-mail Address: [email protected] https://orcid.org/0000-0003-3199-1364 UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, France. Originally published14 Mar 2024https://doi.org/10.1161/ATVBAHA.123.320547Arteriosclerosis, Thrombosis, and Vascular Biology. 2024;0FootnotesFor Sources of Funding and Disclosures, see page XXX.*A. Grandperrin and E. Strock contributed equally.Correspondence to: Gregory Meyer, UPR-4278, LaPEC, Laboratory of Cardiovascular Experimental Physiology, Avignon University, F-84000 Avignon, France. Email gregory.meyer@univ-avignon.fr Previous Back to top Next FiguresReferencesRelatedDetails Advertisement Article InformationMetrics © 2024 American Heart Association, Inc.https://doi.org/10.1161/ATVBAHA.123.320547PMID: 38482695 Originally publishedMarch 14, 2024 Keywordsendotheliumhyperglycemiareactive oxygen speciesrisk factorssodiumPDF download Advertisement SubjectsBasic Science ResearchOxidant StressVascular BiologyVascular Disease

Hyperglycemia (HG) is associated with increased mortality and morbidity in acute ischemic events. Regardless of the tissue or organs involved, the vascular endothelium is a key target of ischemia-reperfusion (I/R) injury severity. Among endothelium-protective strategies, exercise has been widely described as useful. However, whether this strategy is able to impact the deleterious effect of HG on endothelial function during I/R has never been challenged. For this, 48 male Wistar rats were randomized into 4 groups: sedentary (Sed) or exercised (Ex, 45 min/day, 5 days/week for 5 weeks) rats, treated (hyperglycemic, HG) or not (normoglycemic, NG) with streptozotocin (40 mg/kg, 48 h before procedure). Vascular I/R (120/15 min) was performed by clamping the femoral artery. Arterial and downstream muscular perfusions were assessed using laser speckle contrast imaging. Vascular endothelial function was assessed in vivo 15 min after reperfusion. HG was responsible for impairment of reperfusion blood flow as well as endothelial function. Interestingly exercise was able to prevent those impairments in the HG group. In agreement with the previous results, HG increased reactive oxygen species production and decreased nitric oxide bioavailability whereas exercise training normalized these parameters. It, therefore, appears that exercise may be an effective prevention strategy against the exacerbation of vascular and muscular damage by hyperglycemia during I/R.

Non-nutritive sweeteners (NNS) are among the most widely used food additives worldwide. Their substitution to sugar is presented as one of the solutions to prevent cardiometabolic disease, especially as they have a sweet taste but very low-energy content. However, several recent studies have questioned their physiological inactivity, which was the basis for their approval by health authorities. The main objective of this study was to evaluate the acute and chronic effects of artificial NNS consumption on glycemic control in lean and diet-induced mice models. Consequently, we evaluated the acute effects of NNS acesulfame-potassium (aceK) and sucralose on glucose tolerance, insulin sensitivity and insulin secretion measured in blood and at the beta-cells pancreatic level of mice. In another set of mice, we compared the effects of aceK or sucralose supplementations to sugar consumption during a 12 week long high-fat (HF) diet. At the end of the 12 weeks of supplementation, we evaluated the influence of these different conditions on glucose metabolism and body fat distribution. First, we reported, in our mice models, that oral glucose tolerance tests (OGTTs) after acute sucralose gavage were improved significantly compared to AceK gavage and control situation (vehicle). These acute effects on blood glucose levels after sucralose ingestion were not directly explained by a significant increase neither in beta cells insulin secretion nor in insulin sensitivity. Interestingly, we further demonstrated that both NNS chronic consumption were able to attenuate significantly the deleterious effect of HF diet on glycemic control (glucose tolerance and insulin sensitivity), independently of caloric intake. Moreover, we reported in HF mice supplemented with NNS a lower accumulation of adipose tissue in the inguinal and subcutaneous compartments which was associated with a reduction in body mass in these groups. Surprisingly, our results demonstrate that even an acute consumption of widely used NNS sucralose and AceK is able to alter glucose metabolism. When repeated over time, the consumption of these NNS also seems to be able to reduce deleterious effects of HF diet on glycemic control but also on body composition. These results may contribute to a better understanding of the effects of NNS on metabolic health, but further studies are needed to decipher underlying mechanisms.

Previous investigations from our group and others revealed that hyperglycemia (HG) impairs vascular endothelial function particularly through an increased oxidative stress. For a long time, little was known about the glucose transport mechanisms responsible for these alterations in the cardiovascular system under HG conditions. However, recent work has shown the involvement of the sodium myo-inositol transporter 1 (SMIT1) of the sodium-glucose co-transporter (SGLT) family in HG-dependent ROS production. However, few studies have focused on the involvement of these transporters in the vascular effects of HG. In this context, we aimed to evaluate the implication of the different SGLT isoforms on the increased oxidative stress and the subsequent vascular dysfunction reported during HG. Firstly, Gene expression of the 7 isoforms of SGLT Transporters was evaluated in vascular tissues by PCR. Then, in order to study the involvement of SGLT/SMIT transporters in HG-related vascular alterations, we incubated (1 hour, 100 mM) aortic rings from Wistar rats with either of the following sugars which each stimulate either one or more isoforms of these transporters (Glucose: GLUTs/SGLTs/SMITs transporters; α-MG: SGLT 1 to 5; Galactose: SGLT 1/2; myo-inositol: SMIT 1/2; L-Fucose: SMIT1). Then, incubated vessels were either mounted in organ chambers to study vascular endothelial function or embedded in OCT in order to measure reactive oxygen species (ROS) production with DHE fluorescence. First, PCR analyses highlighted that SMIT1 appears to be the transporter of the SGLT family whose gene expression is predominant in vascular tissue. As expected from previous studies, vascular exposure to glucose was responsible for an endothelial dysfunction associated with a higher ROS production. Interestingly, endothelial impairments and increased ROS production were not observed when SGLTs were stimulated with either α-MG or galactose. The main result of this work was that myo-inositol exposure was responsible for similar endothelial alteration than glucose and that L-Fucose which transport is highly dependent of SMIT1 was responsible for an exacerbation of those impairments. These results highlight the implication of SMIT1 in the increased oxidative stress and endothelial dysfunctions observed during HG in vascular tissues.

Cette dernière décennie, l’industrie agroalimentaire a largement adapté son offre avec la généralisation de produits contenant des édulcorants pour remplacer les sucres ajoutés ou sucres libres et, ainsi, limiter les apports caloriques tout en maintenant l’appétence aux produits. Cependant, nombre de données observationnelles questionnent l’efficacité et la sécurité de cette stratégie. En effet, les édulcorants semblent présenter des avantages et des inconvénients sur les plans du comportement alimentaire et des conséquences métaboliques. Cette disparité des résultats semble pouvoir s’expliquer par les mécanismes d’action et l’impact spécifique des différentes molécules édulcorantes. En effet, bien que tous les édulcorants ciblent les mêmes récepteurs cellulaires, il faut rappeler que chaque édulcorant peut différer dans sa structure chimique, son profil pharmacocinétique et, plus important encore, dans son activité pharmacologique, et ainsi induire des réponses physiologiques ou pathologiques propres. De manière générale, les méta-analyses indiquent une augmentation du risque de développer un diabète de type 2 lorsque la consommation de ces édulcorants est importante, mais les données expérimentales ne sont pas aussi tranchées. Cet article présente les mécanismes d’action des édulcorants les plus utilisés et les différents effets associés à la consommation d’édulcorants sur le comportement alimentaire et ses conséquences sur la gestion du poids et le contrôle métabolique.

Artificial sweeteners (AS) are well known to activate two categories of receptors; sweet taste receptor with high affinity and bitter taste receptors with low affinity. Interestingly, recent data from our and other groups suggested that these two receptors families are expressed throughout the arterial tree. Therefore, it could be interesting to explore if AS may have an impact on vascular function, and to decipher the role of these taste receptors. The aims of this ongoing work is to investigate whether AS, like sucralose and acesulfame potassium (AceK) (1) exhibit vasomotor effect and (2) in that case determine the underlying mechanisms. Biomolecular and functional investigations have been performed on isolated rodent aortas, human dermal micro-arteries and omental arteries. Ex vivo vasomotor function was assessed using isometric tension measurements in organ bath systems. We first confirmed that both endothelial and smooth muscle cells from rodent and human arteries express the transcripts encoding for TAS1R2 and TAS1R3; the heterodimer receptor known to be responsible for the sweet taste. Our ex vivo data showed that only high concentrations (about 10 mM) of AceK and sucralose induce vasomotor responses. While AceK exhibited a vasoconstrictive effect, sucralose induced vasorelaxation. Both responses were found to be independent of the endothelium. Pharmacological inhibition (gurmarin and lactisol) and the use of a TAS1R3 KO mice model demonstrated that AS vasomotor effects do not rely on the sweet taste receptors. In contrast, inhibition of TAS2Rs abolished all responses suggesting that bitter taste receptors are more likely responsible for the AS-induced vascular effects. Additionally, our last observations show that the vasoconstrictive effect of AceK is mediated by RhoA/ROCK pathway. These evidences support the idea that AS can alter vasomotor signaling in the smooth muscle cells. These acute effects are probably mediated by the bitter taste receptor family. Their activation at the vascular level as well as the underlying pathways remains poorly understood, and the physiopathological consequences need to be further investigated.

Mitochondrial fission is a key trigger of cardiac ischemia-reperfusion injuries (IR) injuries. Despite exercise training (ExTr) is known as an efficient strategy to protect the heart, its impact on the dynamic of the mitochondrial network remain to be investigated. To evaluate the impact of ExTr on the process of mitochondrial fission during IR. Isolated hearts from ExTr or Sedentary (Sed) rats were subjected to IR. Hearts samples were collected after 10 min of reperfusion for biochemical assays or electron microscopic analysis. Finally, DHR123 was used to detect ROS production on isolated cardiomyocytes treated or not with the mitochondrial fission inhibitor Mdivi1. We confirmed on isolated rat hearts that ExTr reduced heart sensitivity to IR. This was associated with lower ROS production evaluated by DHE fluorescence and higher mitochondria Ca2+ retention capacities. We next confirmed that IR was associated with mitochondrial fission as well as the translocation and activation of the Dynamin related protein 1 (Drp1), known as the central regulator of mitochondrial fission. Interestingly, ExTr limited both the activation of Drp1 and the fission of mitochondria. We also reported that ExTr tended to increase the level of Mfn2, known as a central regulator of mitochondrial fusion. Finally, on isolated cardiomyocytes stimulated with H2O2 to mimic IR, we reported that Mdivi1 impact the level of ROS production only in Sed cells. This confirms that mitochondrial fission was more pronounced in Sed cells and contributes to increased ROS production during IR. Altogether, our results support the hypothesis that ExTr is able to modulate the dynamic of the mitochondrial network during IR, which could participate to exercise-induced cardioprotection.

The excess consumption of added sugar is consistently found to be associated with weight gain, and a higher risk of type 2 diabetes mellitus, coronary heart disease, and stroke. In an effort to reduce the risk of cardiometabolic disease, sugar is frequently replaced by low- and null-calorie sweeteners (LCSs). Alarmingly, though, emerging evidence indicates that the consumption of LCSs is associated with an increase in cardiovascular mortality risk that is amplified in those who are overweight or obese. Sucralose, a null-caloric high-intensity sweetener, is the most commonly used LCS worldwide, which is regularly consumed by healthy individuals and patients with metabolic disease. To explore a potential causal role for sucralose in increased cardiovascular risk, this present review summarizes the preclinical and clinical data from current research detailing the effects of sucralose on systems controlling food intake, glucose homeostasis, and gut microbiota.

Originally thought to be physiologically inert, artificial sweeteners are more and more recognized to alter various biological functions through their interaction with the sweet taste receptor in extraoral sites. Alarmingly, recent epidemiological data have shown that frequent consumption of artificial sweeteners (AS) is associated with an increased risk of vascular events. However, to date, no studies have tested the hypothesis that AS might directly impact the vasculature. The aim is to characterize the effect of the highly consumed AS, Sucralose and Acesulfame K (AceK), on the vascular wall. The specific objective of the present study is to focus on the vasomotor function. Biomolecular and functional investigations were performed on isolated rodent aortas, human dermal micro-arteries and omental arteries. Ex-vivo vasomotor function was assessed using isometric tension measurements in an organ bath system. Our preliminary data show that mRNA of both T1R2 and T1R3, the two subunits of the sweet taste receptor, are expressed in the vascular wall. Cumulative addition of AceK or sucralose revealed that high concentration (10 mM) of these molecules exert respectively vasoconstrictive and vasorelaxant properties on both rodent and human arteries. Lower concentrations (1 mM) of AceK were associated with an exacerbated vasoreactivity to the α1 adrenergic agonist phenylephrine. All these effects were independent of the presence of the endothelium. Surprisingly, T1R inhibition with gurmarin, as well as T1R3 invalidation (KO mice), had no consequence on sucralose and AceK vasoactive effects. Our work first show that AS can modulate smooth muscle vascular tone. The in-vivo significance and molecular mechanisms involved remain to be determined. Future investigations will also address other vascular functions to better understand the possible consequences of AS consumption on the cardiovascular system.

SCOPE:A main risk factor of atherosclerosis is a Western diet (WD) rich in n-6 polyunsaturated fatty acids (PUFAs) sensitive to oxidation. Their oxidation can be initiated by heme iron of red meat leading to the formation of 4-hydroxy-2-nonenal (4-HNE), a cytotoxic aldehyde. An increased 4-HNE production is implicated in endothelial dysfunction and atherosclerosis. By contrast, a diet rich in proanthocyanidins reduces oxidative stress and arterial diseases. This study evaluates the effects of a WD on vascular integrity in ApolipoproteinE (ApoE-/- ) mice and the protective capacity of apple extract and puree rich in antioxidant proanthocyanidins.METHODS AND RESULTS:ApoE-/- mice are fed during 12 weeks with a WD with or without n-6 PUFAs. Moreover, two WD + n-6 PUFAs groups are supplemented with apple puree or phenolic extract. An increase in digestive 4-HNE production associated with a rise in plasmatic 4-HNE and oxidized LDL concentrations is reported. Oxidizable n-6 PUFAs consumption is associated with a worsened endothelial dysfunction and atherosclerosis. Interestingly, supplementations with apple polyphenol extract or puree prevented these impairments while reducing oxidative stress.CONCLUSION:n-6 lipid oxidation during digestion may be a key factor of vascular impairments. Nevertheless, an antioxidant strategy can limit 4-HNE formation during digestion and thus durably protect vascular function.

Endothelial nitric oxide synthase (eNOS) activation in the heart plays a key role in exercise-induced cardioprotection during ischemia-reperfusion, but the underlying mechanisms remain unknown. We hypothesized that the cardioprotective effect of exercise training could be explained by the re-localization of eNOS-dependent nitric oxide (NO)/S-nitrosylation signaling to mitochondria. By comparing exercised (5 days/week for 5 weeks) and sedentary Wistar rats, we found that exercise training increased eNOS level and activation by phosphorylation (at serine 1177) in mitochondria, but not in the cytosolic subfraction of cardiomyocytes. Using confocal microscopy, we confirmed that NO production in mitochondria was increased in response to H2O2 exposure in cardiomyocytes from exercised but not sedentary rats. Moreover, by S-nitrosoproteomic analysis, we identified several key S-nitrosylated proteins involved in mitochondrial function and cardioprotection. In agreement, we also observed that the increase in Ca2+ retention capacity by mitochondria isolated from the heart of exercised rats was abolished by exposure to the NOS inhibitor L-NAME or to the reducing agent ascorbate, known to denitrosylate proteins. Pre-incubation with ascorbate or L-NAME also increased mitochondrial reactive oxygen species production in cardiomyocytes from exercised but not from sedentary animals. We confirmed these results using isolated hearts perfused with L-NAME before ischemia-reperfusion. Altogether, these results strongly support the hypothesis that exercise training increases eNOS/NO/S-nitrosylation signaling in mitochondria, which might represent a key mechanism of exercise-induced cardioprotection.

Introduction: Arterial Hypertension (AHT) is a major cause of premature death worldwide. We have developed Totum-854 (T-854), a polyphenol-rich botanical composition to reduce the risk of developing AHT. We assessed the chronic effect of T-854 on preventing the development of L-NAME-induced AHT in mice, and the acute effect on blood pressure in spontaneous hypertensive rats (SHR). Methods: 12-week-old C57Bl6/J mice were divided into Control, L-NAME, and L-NAME + T-854 group. L-NAME (100 mg/kg/day) was dissolved in drinking water. Mice received either T-854 (450 mg/kg) or vehicle by gavage once a day for three weeks . The arterial pressure was assessed using the CODA® Tail-Cuff System every week for three weeks. 12-week-old SHR rats received a dose of vehicle or T-854 (1250mg/kg) per os with a 48h-wash-out interval between two gavages, in random order. Arterial pressure was recorded during 24h post-gavage with a radio-telemetry device (HD-S10, DSI) directly implanted into the abdominal aorta. Results: In mice, L-NAME increased systolic (SBP; from 105±3 to 130±1 mmHg, p<0.0001), diastolic (DBP; from 77±3 to 97±2 mmHg, p<0.0001) and mean (MBP; from 86±3 to 108±2 mmHg, p<0.0001) blood pressure along the 3 weeks of treatment. Interestingly, in T-854-supplemented mice, SBP was significantly reduced from the first week of supplementation, and DBP and MBP from the second week of supplementation. After three weeks, T-854 lowered the SBP by 16% (p<0.0001), the DBP by 20% (p<0.05) and the MBP by 18 % (p<0.01), in comparison to L-NAME mice. In the SHR study, SBP and DBP were reduced during 24h recording after T-854 gavage in comparison to vehicle, with a 24h-AUC decreased by 108 ± 87.8 and 84.4 ± 69.3 mmHg.h, respectively. Conclusions: In conclusion, T-854 appears as an efficient strategy to prevent AHT and this effect was confirmed in two different preclinical models: L-NAME-induced AHT in mice and SHR rats.

Objective: Arterial Hypertension (HTA) is a major cause of premature death worldwide, with an estimated global prevalence of 1.13 billion people. Polyphenolic compounds have been shown promising effects in the context of HTA management. We have developed Totum-854 (T-854), a polyphenol-rich botanical composition to reduce the risk of developing AHT. We assessed the chronic effect of T-854 on preventing the development of N(G)-Nitro-L-arginine-methyl ester (L-NAME)-induced AHT in mice. Design and method: Twelve-week-old C57Bl6/J mice were divided into 3 groups: Control (n = 11), L-NAME (n = 11), and L-NAME + T-854 (n = 11). L-NAME (100 mg/kg/day) was dissolved in drinking water. Mice were gavaged once a day for three weeks with either T-854 (450 mg/kg) or vehicle. The arterial pressure was assessed using the CODA® Tail-Cuff System every week for three weeks. Effects of T-854 on in vitro angiotensin-converting enzyme (ACE) activity was also assessed by a HPLC-UV method. Results: Body weight evolution was not significantly different between the 3 groups over the study period. As expected, L-NAME increased systolic (SBP; from 105 ± 3 to 130 ± 1 mmHg, p < 0.0001), diastolic (DBP; from 77 ± 3 to 97 ± 2 mmHg, p < 0.0001) and mean (MBP; from 86 ± 3 to 108 ± 2 mmHg, p < 0.0001) blood pressure along the 3 weeks of treatment. Interestingly, in T-854-supplemented mice, SBP was significantly reduced from the first week of supplementation and DBP and MDP from the second week of supplementation. After three weeks of supplementation, T-854 lowered the SBP by 16% (p < 0.0001), the DBP by 20% (p < 0.05) and the MBP by 18 % (p < 0.01), in comparison to L-NAME mice. Moreover, in vitro experiments showed an inhibitory effect of T-854 on ACE activity. Conclusions: In conclusion, this study showed that T-854 prevents L-NAME-induced HTA in mice. ACE inhibition may partly explain the preventive effects of T-854 on HTA development in this model. T-854 is a promising new approach for the prevention of HTA.