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Phytofluene is a colorless carotenoid with potential health benefits that displays a higher bioavailability compared to carotenoids such as lutein, β-carotene or lycopene. Several studies suggest its bioavailability displays an elevated interindividual variability. The aim of this work is to investigate whether a combination of SNPs is associated with this variability.Thirty-seven healthy adult males consume a test meal that provided phytofluene from a tomato puree. Phytofluene concentrations are measured at fast and in chylomicrons at regular time intervals after meal intake. Identification of the combination of SNPs that best explained the interindividual variability of the phytofluene response is assessed by partial least squares regression. There is a large interindividual variability in the phytofluene response, with CV = 88%. Phytofluene bioavailability is positively correlated with fasting plasma phytofluene concentration (r = 0.57; p = 2 × 10This study reports a combination of SNPs that is associated with a significant part of the interindividual variability of phytofluene bioavailability in a healthy male adult population.

International audience; Purpose1) To test the hypothesis of the existence of a perinatal vitamin A (VA) programming of VA metabolism and to better understand the intestinal regulation of VA metabolism.MethodsOffspring from rats reared on a control (C) or a VA-deficient (D) diet from 6 weeks before mating until offspring weaning, i.e., 7 weeks after mating, were themselves reared on a C or D diet for 19 weeks, resulting in the following groups: C–C (parents fed C—offspring fed C), D-C, C-D and D-D. VA concentrations were measured in plasma and liver. β-Carotene bioavailability and its intestinal conversion rate to VA, as well as vitamin D and E bioavailability, were assessed after gavages with these vitamins. Expression of genes involved in VA metabolism and transport was measured in intestine and liver.ResultsC–D and D–D had no detectable retinyl esters in their liver. Retinolemia, hepatic retinol concentrations and postprandial plasma retinol response to β-carotene gavage were higher in D–C than in C–C. Intestinal expression of Isx was abolished in C–D and D–D and this was concomitant with a higher expression of Bco1, Scarb1, Cd36 and Lrat in males receiving a D diet as compared to those receiving a C diet. β-Carotene, vitamin D and E bio-availabilities were lower in offspring receiving a D diet as compared to those receiving a C diet.ConclusionA VA-deficient diet during the perinatal period modifies the metabolism of this vitamin in the offspring. Isx-mediated regulation of Bco1 and Scarb1 expression exists only in males severely deficient in this vitamin. Severe VA deficiency impairs β-carotene and vitamin D and E bioavailability.

International audience; Enriching cereals-based products with bioactive compounds is a valuable strategy to improve product quality. We studied carotenoid bioaccessibility and intestinal uptake from a pumpkin-enriched porridge, cookies and sponge cakes by using in vitro digestion coupled with Caco-2 cell uptake. Among the carotenoids recovered in different products, alpha-carotene was the most important abundant one. However, lutein displayed a significantly higher bioaccessibility compared to alpha-carotene and 0-carotene in baked products (up to 10.28% compared to 1.22% and 0.88%, respectively). alpha-Carotene was the only carotenoid recovered in Caco-2 cells after micelle incubation. Cookie micelles led to the highest percentage of alpha-carotene cell uptake (2.33% and 1.38% for cookies with butter and cookies with vegetable oil, respectively) compared to the other baked products, followed by dry pumpkin puree micelles (1.31%). Overall, our data show that both bioaccessiblity and cell uptake of carotenoids from cereal-based products are variable and highly depend on food formulation and structure.

International audience; (1) Background: vitamin E is often supplemented in the form of tocopherol acetate, but it has poor bioavailability and can fail to correct blood tocopherol concentrations in some patients with severe cholestasis. In this context, α-tocopheryl polyethylene glycol succinate 1000 (TPGS) has been of value, but very little is known about the mechanisms of its absorption. The aim of our work was to evaluate the mechanisms of absorption/secretion of TPGS compared to tocopherol acetate (TAC) and α-tocopherol by human enterocyte-like Caco-2 TC7 cells. (2) Methods: two weeks post-confluence Caco-2 cells were incubated with tocopherol- or TAC- or TPGS-rich mixed micelles up to 24 h and, following lipid extraction, TAC and tocopherol amounts were measured by high performance liquid chromatography (HPLC) in apical, cellular, and basolateral compartments. (3) Results: at equivalent concentrations of tocopherol in the apical side, the amounts of tocopherol secreted at the basolateral pole of Caco-2 cells are (i) significantly greater when the tocopherol is in the free form in the micelles; (ii) intermediate when it is in the TAC form in the micelles (p \textless 0.001); and (iii) significantly lower with the TPGS form (p \textless 0.0001). Interestingly, our results show, for the first time, that Caco-2 cells secrete one or more esterified forms of the vitamin contained in TPGS at the basolateral side.

Abetalipoproteinemia (FHBL-SD1) and chylomicron retention disease (FHBL-SD3) are rare recessive disorders of lipoprotein metabolism due to mutations in MTTP and SAR1B genes, respectively, which lead to defective chylomicron formation and secretion. This results in lipid and fat-soluble vitamin malabsorption, which induces severe neuro-ophthalmic complications. Currently, treatment combines a low-fat diet with high-dose vitamin A and E supplementation but still fails in normalizing serum vitamin E levels and providing complete ophthalmic protection. To explore these persistent complications, we developed two knock-out cell models of FHBL-SD1 and FHBL-SD3 using the CRISPR/Cas9 technique in Caco-2/TC7 cells. DNA sequencing, RNA quantification and Western blotting confirmed the introduction of mutations with protein knock-out in four clones associated with i) impaired lipid droplet formation and ii) defective triglyceride (−57.0 ± 2.6% to −83.9 ± 1.6%) and cholesterol (−35.3 ± 4.4% to −60.6 ± 3.5%) secretion. A significant decrease in α-tocopherol secretion was also observed in these clones (−41.5 ± 3.7% to −97.2 ± 2.8%), even with the pharmaceutical forms of vitamin E: tocopherol-acetate and tocofersolan (α-tocopheryl polyethylene glycol succinate 1000). MTTP silencing led to a more severe phenotype than SAR1B silencing, which is consistent with clinical observations. Our cellular models thus provide an efficient tool to experiment with therapeutic strategies and will allow progress in understanding the mechanisms involved in lipid metabolism.

International audience; Scope Most people are vitamin D insufficient around the world. Vitamin D intestinal absorption should thus be optimized. The role of the ATP-binging cassette G5/G8 (ABCG5/G8) heterodimer in vitamin D intestinal efflux is investigated. Methods and Results Both cholecalciferol and 25-hydroxycholecalciferol apical effluxes are increased by ABCG5/G8 overexpression in human Griptite cells. Mice deficient in ABCG5/G8 at the intestinal level (I-Abcg5/g8(-/-) mice) display an accumulation of cholecalciferol in plasma in females and in liver in males compared to control animals. I-Abcg5/g8(-)(/)(-) mice display a delay in cholecalciferol postprandial response after gavage compared with controls. 25-Hydroxycholecalciferol transfer from plasma to lumen is observed in vivo in intestine-perfused mice, and the lack of intestinal ABCG5/G8 complex induces a decrease in this efflux, while vitamin D bile excretion remains unchanged. Conclusion Overall, it is showed for the first time that the ABCG5/G8 heterodimer regulates the kinetics of absorption of dietary vitamin D by contributing to its efflux back to the lumen, and that it also participates in vitamin D transintestinal efflux.

International audience; Scope Cholesterol bioavailability displays a high interindividual variability, partly due to genetic factors. Existing studies have focused on single nucleotide polymorphisms (SNPs) analyzed individually, which only explained a minor fraction of the variability of this complex phenotype. The aim is to identify a combination of SNPs associated with a significant part of the variability in cholesterol bioavailability. Methods and results Thirty-nine healthy adult males are given a standard test snack containing 80 mg heptadeuterated (D7) cholesterol. The plasma D7-cholesterol concentration is measured at equilibrium 40 h after test snack intake. The D7-cholesterol response (D7-cholesterol/total cholesterol concentration) exhibits a relatively high interindividual variability (CV = 32%). The association of exonic SNPs in candidate genes (188 genes involved in or related to cholesterol metabolism) with the plasma D7-cholesterol response is assessed by univariate statistics followed by partial least squares regression. A significant model (p-value after cross-validation ANOVA = 1.64 x 10(-7)) that includes 8 SNPs (SOAT2-rs9658625,DNAH11-rs11768670,LIPC-rs690,MVK-rs2287218,GPAM-rs10787428,APOE-rs7412,CBS-rs234706, andWRN-rs1801196) explains 59.7% of the variance in cholesterol bioavailability (adjustedR(2)). Conclusion Here a combination of SNPs is significantly associated with the variability in dietary cholesterol bioavailability in healthy adult males.

International audience; Scope The effect of vitamin A deficiency on vitamin A and lipid postprandial metabolism in young rats is addressed, considering the effect of sex. Methods and Results Sprague-Dawley rats are fed either 400 UI.kg(-1) vitamin A diet (vitamin A-deficient (VAD) diet) or 2300 UI.kg(-1) vitamin A (control diet), before being mated. Mothers receive the same VAD or control diet during gestation and lactation. Offspring receive the same diet than mothers until 8 weeks of age. VAD diet-fed female and male offspring display a severe vitamin A deficiency with no body weight or glucose tolerance defects. Fasting plasma triglyceride concentrations are decreased in VAD diet-fed animals compared to controls (p < 0.05). Retinyl ester postprandial responses after vitamin A gavage, expressed as area under the curves, are not different in VAD diet-fed and control animals, although retinyl ester postprandial peak is significantly delayed (p < 0.05) in VAD diet-fed rats. Lipids also accumulate in the distal part of the intestine after gavage and [1-C-13]-oleate postprandial response is decreased in VAD diet-fed males. Conclusion Vitamin A deficiency modulates both vitamin A absorption rate and lipid postprandial metabolism, which can partly explain the altered fasting lipid status observed in VAD diet-fed offspring.

International audience; ABCB1 (P-glycoprotein/MDR1) is a multidrug efflux transporter that has previously been involved in cholesterol and vitamin D metabolism. Our aim was to explore whether ABCB1 is also involved in vitamin K efflux. Vitamin K apical efflux was significantly decreased in presence of ABCB1 inhibitor in Caco-2 cells (− 20.4%; p < 0.05) and increased in Griptite cells overexpressing ABCB1 (+40.7%; p < 0.05). In vivo, the vitamin K postprandial response was higher in male Abcb1 − /− mice after gavage compared to control animals (+115%; p < 0.05), but was unchanged in female mice. Finally, a vitamin K transintestinal efflux and a biliary vitamin K efflux were observed, but the specific involvement of ABCB1 could not be confirmed in these pathways. Overall, we showed for the first time that ABCB1 is involved in enterocyte vitamin K efflux in both cell and mouse models and regulates vitamin K absorption in mice. Recently, the multidrug membrane transporter ABCB1 (Sharom, 2011) has been identified to contribute to the intestinal transport of vitamin D (Margier et al., 2019

International audience; Scope: To investigate the formation and absorption of lycopene (LYC) metabolites in the human upper gastrointestinal lumen, in the absence and presence of iron. Methods: Healthy males (n = 7) consumed test meals that deliver ≈22 mg LYC + ≈0.3 mg apo-lycopenals from oleoresin without (-FeSO4) and with ferrous sulfate (160 mg, +FeSO4). Subjects were intubated with a naso-gastric/naso-duodenal tube. Digesta, blood plasma, and the triglyceride-rich lipoprotein (TRL) fractions of plasma were analyzed using LC–MS/MS, to measure LYC and apo-lycopenoids. Results: Digesta LYC concentrations increased with time (p = 1.2 × 10−7), decrease with time × iron (p = 1.1 × 10−5), and remain ≈200× higher than apo-lycopenals/lycopenone. Digesta apo-8′-, -10′-, -12′-, -14′-, -15-lycopenal, and apo-13-lycopenone concentrations increased with time (p < 0.01), apo-12′-, -14′-, -15-lycopenal, apo-13-lycopenone increase with iron (p < 0.05), and time × iron decrease apo-8′-, -10′-, -12′-, -14′-, -15-lycopenal, apo-13-lycopenone concentrations (p < 0.01). A 1.9-fold decrease in LYC TRL area-under-the-time-concentration-curve is observed after the test meal +FeSO4 versus the test meal –FeSO4 (p = 0.02). Apo-lycopenals were detected in later TRL fractions, and no apo-lycopenols or apo-lycopenoic acids were observed in any samples. Conclusions: FeSO4 reduces LYC absorption. Apo-lycopenals appear to be absorbed from foods, and not made in significant quantities during digestion.

International audience; Scope : It is widely advised to increase pulse consumption. However, pulses are rich in molecules displaying lipid‐lowering properties, including fibers, phytates, saponins and tannins. We thus explored the effects of pulses on fat‐soluble vitamin bioavailability. Methods : We assessed vitamin A (β‐carotene and retinyl‐palmitate), vitamin E (α‐tocopherol), vitamin D (cholecalciferol) and vitamin K (phylloquinone) bioaccessibility, i.e. micellarization after in vitro digestion of meals containing either potatoes (control), household‐cooked or canned pulses. The obtained mixed micelles were delivered to Caco‐2 cells to evaluate vitamin uptake. We then specifically assessed the impact of fibers, phytates, saponins and tannins on both phylloquinone (used as a model vitamin) bioaccessibility and uptake. Results : The presence of pulses significantly decreased both vitamin bioaccessibility (up to ‐65% for β‐carotene, ‐69% for retinyl‐palmitate, ‐45% for cholecalciferol, ‐53% for α‐tocopherol and ‐67% for phylloquinone) and uptake (‐40% for retinyl‐palmitate, ‐67% for cholecalciferol, ‐50% for α‐tocopherol and ‐57% for phylloquinone). Effects on bioaccessibility, but not on uptake, were dependent on pulse cooking method. Phylloquinone bioaccessibility was specifically impacted by saponins, tannins and fibers while its uptake was impacted by saponins, fibers and phytates. Conclusion : Pulses can alter fat‐soluble micronutrient bioavailability. Pulses should thus be cooked appropriately and consumed within micronutrient‐rich meals.

Background/objective The number of long-term survivors of childhood acute leukemia (AL) is substantially growing. These patients are at high risk for metabolic syndrome (MS), especially those who received total body irradiation (TBI). The consequences of children’s irradiation on adipose tissue (AT) development in adulthood are currently unknown. The objective of this study is to assess the impact of TBI on AT of childhood AL survivors. Design We compared the morphological and functional characteristics of AT among survivors of childhood AL who developed MS and received (n = 12) or not received (n = 12) TBI. Subjects/methods Body fat distribution and ectopic fat stores (abdominal visceral and liver fat) were evaluated by DEXA, MRI and 1H-spectroscopy. Functional characteristics of subcutaneous AT were investigated by studying gene expression and pre-adipocyte differentiation in culture. Results Patients who have received TBI exhibited a lower BMI (minus 5 kg/m2) and a lower waist circumference (minus 14 cm), especially irradiated women. Despite the lower quantity of intra-abdominal AT, irradiated patient displayed a nearly two-fold greater content of liver fat when compared to non-irradiated patient (17 vs 9%, P = 0.008). These lipodystrophic-like features are supplemented by molecular abnormalities in subcutaneous AT of irradiated patients: decrease of gene expression of SREBP1 (minus 39%, P = 0.01) and CIDEA (minus 36%, P = 0.004) and a clear alteration of pre-adipocyte differentiation. Conclusions These results strongly support the direct effect of irradiation on AT, especially in women, leading to specific nonalcoholic fatty liver disease, despite lower BMI. A long-term appropriate follow-up is necessary for these patients.

The mechanisms of main tomato carotenes (phytoene, phytofluene, lycopene and β-carotene) intestinal absorption are still only partly understood. We thus compared carotene bioavailability in mice after gavage with carotene-rich oil-in-water emulsions. We also determined each carotene absorption profile along the duodenal-ileal axis of the intestine to identify their respective absorption sites and compared these profiles with the gene expression sites of their identified transporters, i.e. SR-BI and CD36. Our data show that phytofluene presented a significantly higher bioavailability compared to lycopene and β-carotene (areas under the curve of 0.76 ± 0.09 vs. 0.30 ± 0.05, 0.09 ± 0.05 and 0.08 ± 0.01 μmol/L·h for phytofluene, phytoene, lycopene and β-carotene, respectively). β-Carotene was mostly converted in the proximal and median intestine. Phytoene and phytofluene accumulation tended to be more important in the distal intestine, which did not correlate with the proximal expression of both Scarb1 and CD36. Overall, these results highlight the high bioavailability of phytofluene. Junta de Andalucía CAROTINCO-P12-AGR-1287

Alperujo&mdash, a two-phase olive mill waste that is composed of olive vegetation water and solid skin, pulp, and seed fragments - is a highly valuable olive by-product due to its high content in phenolic compounds. In this study, we assessed whether &beta, cyclodextrin (&beta, CD), which is used to extract and protect alpejuro phenolic compounds (hydroxytyrosol-O-glucoside, tyrosol, caffeic, and p-coumaric acids) could impact on their bioaccessibility (i.e., the percentage of molecule found in the aqueous phase of the digesta) and uptake by intestinal cells, by using an in vitro digestion model and Caco-2 TC7 cells in culture, respectively. Our results showed that &beta, CD did not change the bioaccessibility of the selected phenols. Hydroxytyrosol-O-glucoside and caffeic did not cross Caco-2 cell monolayers. Conversely ferulic acid, identified as the main caffeic acid intestinal metabolite, was absorbed through intestinal cell monolayers (~20%). Interestingly, &beta, CD moderately but significantly improved the local absorption of tyrosol and p-coumaric acid (2.3 + 1.4% and 8.5 &plusmn, 4.2%, respectively, p &lt, 0.05), even if their final bioavailability (expressed as bioaccessibility &times, absorption by Caco-2 cells) was not modified (16.2 &plusmn, 0.6% vs. 16.8 &plusmn, 0.5% for tyrosol and 32.0 &plusmn, 3.2% vs. 37.2 &plusmn, 3.2% for p-coumaric acid, from pure alperujo and alperujo complexed with &beta, CD, respectively). Overall, our results show that &beta, CD is an interesting extraction and storage agent for phenolic compounds that does not alter their in vitro bioavailability.

Background Asymmetric β-apo-carotenoids (nonvitamin A-active metabolites) of provitamin A carotenoids have been observed in humans, but no study has investigated their formation during digestion. Objective The aim of this study was to follow the formation and absorption of asymmetric β-apo-carotenoids during digestion. Design Healthy men were intragastrically and intraduodenally intubated, and randomly assigned to consume a lipid-rich control meal (n = 3) or a lipid-rich test meal containing 20 mg [13C-10]-β-carotene (n = 7). Digesta samples were collected over 5 h, and blood collected over 7 h. The triglyceride-rich lipoprotein (TRL) fractions of plasma were also isolated. Lipophilic extracts of digesta, plasma, and TRL were analyzed via a high-performance liquid chromatography-tandem mass spectrometry method developed to identify [13C]-labeled β-apo-carotenals/carotenone, [13C]-β-apo-carotenols, and [13C]-β-apo-carotenoic acids. Results Relative to [13C]-β-carotene, [13C]-β-apo-carotenal levels remained ∼3 orders of magnitude lower throughout digestion (no [13C]-β-apo-carotenols, or [13C]-β-apo-carotenoic acids were observed). A mixed model determined relative influence of digesta type and time on digesta metabolite level. Increasing time significantly increased the model levels of digesta [13C]-β-apo-10',12',14',15-carotenal and [13C]-β-apo-13-carotenone (P

International audience; Scavenger receptors (SRs) like cluster determinant 36 (CD36) and SR class B type I (SR-BI) play a debated role in lipid transport across the intestinal brush border membrane. We used surface plasmon resonance to analyze real-time interactions between the extracellular protein loops and various ligands ranging from single lipid molecules to mixed micelles. Micelles mimicking physiological structures were necessary for optimal binding to both the extracellular loop of CD36 (lCD36) and the extracellular loop of SR-BI (lSR-BI). Cholesterol, phospholipid, and fatty acid micellar content significantly modulated micelle binding to and dissociation from the transporters. In particular, high phospholipid micellar concentrations inhibited micelle binding to both receptors (−53.8 and −74.4% binding at 0.32 mM compared with 0.04 mM for lCD36 and lSR-BI, respectively, P < 0.05). The presence of fatty acids was crucial for micelle interactions with both proteins (94.4 and 81.3% binding with oleic acid for lCD36 and lSR-BI, respectively, P < 0.05) and fatty acid type substitution within the micelles was the component that most impacted micelle binding to the transporters. These effects were partly due to subsequent modifications in micellar size and surface electric charge, and could be correlated to micellar vitamin D uptake by Caco-2 cells. Our findings show for the first time that micellar lipid composition and micellar properties are key factors governing micelle interactions with SRs.

Pulses display nutritional benefits and are recommended in sustainable diets. Indeed, they are rich in proteins and fibers, and can contain variable amounts of micronutrients. However, pulses also contain bioactive compounds such as phytates, saponins, or polyphenols/tannins that can exhibit ambivalent nutritional properties depending on their amount in the diet. We characterized the nutritional composition and bioactive compound content of five types of prepared pulses frequently consumed in France (kidney beans, white beans, chickpeas, brown and green lentils, flageolets), and specifically compared the effects of household cooking vs. canning on the composition of pulses that can be consumed one way or the other. The contents in macro-, micronutrients, and bioactive compounds highly varied from one pulse to another (i.e., 6.9 to 9.7 g/100 g of cooked product for proteins, 4.6 to 818.9 &micro, g/100 g for lutein or 15.0 to 284.3 mg/100 g for polyphenols). The preparation method was a key factor governing pulse final nutritional composition in hydrophilic compounds, depending on pulse species. Canning led to a greater decrease in proteins, total dietary fibers, magnesium or phytate contents compared to household cooking (i.e., &minus, 30%, &minus, 44%, &minus, 33% and &minus, 38%, p &lt, 0.05, respectively, in kidney beans). As canned pulses are easy to use for consumers, additional research is needed to improve their transformation process to further optimize their nutritional quality.

C-13 beta-Carotene stability during digestion in healthy humans. Annual Meeting of the American-Society-for-Pharmacology-and-Experimental-Therapeutics (ASPET) at Experimental Biology Meeting

International audience; Vitamin E membrane transport has been shown to involve the cholesterol transporters SR-BI, ABCA1 and NPC1L1. Our aim was to investigate the possible participation of another cholesterol transporter in cellular vitamin E efflux: ABCG1. In Abcg1-deficient mice, vitamin E concentration was reduced in plasma lipoproteins whereas most tissues displayed a higher vitamin E content compared to wild-type mice. alpha- and gamma-tocopherol efflux was increased in CHO cells overexpressing human ABCG1 compared to control cells. Conversely, alpha- and gamma-tocopherol efflux was decreased in ABCG1-knockdown human cells (Hep3B hepatocytes and THP-1 macrophages). Interestingly, alpha- and gamma-tocopherol significantly downregulated ABCG1 and ABCA1 expression levels in Hep3B and THP-1, an effect confirmed in vivo in rats given vitamin E for 5 days. This was likely due to reduced LXR activation by oxysterols, as Hep3B cells and rat liver treated with vitamin E displayed a significantly reduced content in oxysterols compared to their respective controls. Overall, the present study reveals for the first time that ABCG1 is involved in cellular vitamin E efflux. (C) 2014 Elsevier B.V. All rights reserved.

International audience; Scope: A single nucleotide polymorphism in the cluster determinant 36 (CD36) gene has recently been associated with plasma alpha-tocopherol concentration, suggesting a possible role of this protein in vitamin E intestinal absorption or tissue uptake. Methods and results: To investigate the involvement of CD36 in vitamin E transport, we first evaluated the effect of CD36 on alpha- and gamma-tocopherol transmembrane uptake and efflux using transfected HEK cells. gamma-Tocopherol postprandial response was then assessed in CD36-deficient mice compared with wild-type mice, after the mice had been fully characterized for their alpha -tocopherol, vitamin A and lipid plasma, and tissue contents. Both alpha- and gamma-tocopherol uptake was significantly increased in cells overexpressing CD36 compared with control cells. Compared with wild-typemice, CD36-deficient mice displayed a significantly decreased cholesterol hepatic concentration, and males exhibited significantly higher triacylglycerol contents in liver, brain, heart, and muscle. Although tissue alpha -tocopherol concentration after adjustment for lipid content was not modified, gamma-tocopherol postprandial response was significantly increased in CD36-deficient mice compared with controls, likely reflecting the postprandial hypertriglyceridemia observed in these mice. Conclusion: Our findings show for the first time that CD36 participates-directly or indirectly-in vitamin E uptake, and that CD36 effect on postprandial lipid metabolism in turn modifies vitamin E postprandial response.

International audience; In the context of the global prevalence of vitamin D insufficiency, we compared two key determinants of the bioavailability of 3 vitamin D forms with significant biopotencies: cholecalciferol, 25-hydroxycholecalciferol and 1-α-hydroxycholecalciferol. To this aim, we studied their incorporation into synthetic mixed micelles and their uptake by intestinal cells in culture. Our results show that 1-α-hydroxycholecalciferol was significantly more solubilized into mixed micelles compared to the other forms (1.6-fold and 2.9-fold improvement compared to cholecalciferol and 25-hydroxycholecalciferol, respectively). In Caco-2 TC7 cells, the hydroxylated forms were taken up more efficiently than cholecalciferol (p < 0.05), and conversely to cholecalciferol, their uptake was neither SR-BI(Scavenger-Receptor class B type I)-nor NPC1L1 (NPC1 like intracellular cholesterol transporter 1)-dependent. Besides, the apical membrane sodium–bile acid transporter ASBT (Apical Sodium-dependent Bile acid Transporter) was not involved, at least in vitro, in the uptake of any of the three vitamin D forms. Further investigations are needed to identify the uptake pathways of both 1-α-hydroxycholecalciferol and 25-hydroxycholecalciferol. However, considering its high bioavailability, our results suggest the potential interest of using 1-α-hydroxycholecalciferol in the treatment of severe vitamin D deficiency.

International audience; Background: Most people require dietaryvitamin D to achieve the recommended concentration of 25-hydroxyvitamin D [25(OH)D] in the blood. However, the response to vitamin D supplementation is highly variable among individuals. Objective: We assessed whether the variability in cholecalciferol bioavailability was associated with single-nucleotide polymorphisms (SNPs) in candidate genes. Methods: In a single-group design, 39 healthy adult men with a mean +/- SD age of 33 +/- 2 y and mean +/- SD body mass index lid kg/m(2)) of 22.9 +/- 0.3 were genotyped with the use of whole-genome microarrays. After an overnight fast, plasma 25(OH)D status was measured, and the subjects then consumed a meal that provided 5 mg cholecalciferol as a supplement. Plasma chylomicron cholecalciferol concentration was measured over 8 h, and cholecalciferol response was assessed by calculating the postprandial area under the curve. Partial least squares regression was used to test the association of SNPs in or near candidate genes (61 genes representing 3791 SNPs) with the postprandial cholecalciferol response. Results: The postprandial chylomicron cholecalciferol concentration peaked at 5.4 h. The cholecalciferol response was extremely variable among individuals (CV: 47%). It correlated with the chylomicron triglyceride (TG) response (r = 0.60; P < 0.001) but not with the fasting plasma 25(OH)D concentration (r = 0.04; P = 0.83). A significant (P = 1.32 x 10(-4)) partial least squares regression model that included 17 SNPs in 13 genes (including 5 that have been associated with chylomicron TG response) was associated with the variance in the cholecalciferol response. Conclusion: In healthy men, there is a high interindividual variability in cholecalciferol bioavailability that is associated with a combination of SNPs located in or near genes involved in both vitamin D and lipid metabolism. This trial was registered at clinicaltrials.gov as NCT02100774.

Introduction et but de l’etude Une part significative de la vitamine D presente dans l’organisme humain est produite au niveau de la peau par exposition a la lumiere ultraviolette. Neanmoins, pour obtenir ou maintenir un statut en vitamine D satisfaisant, une majorite d’individus doit consommer de la vitamine D, soit incluse dans l’alimentation, soit sous forme de supplements. Il a ete montre que la reponse sanguine a la supplementation en vitamine D presentait une forte variabilite interindividuelle. En outre, le transport de la vitamine D est en partie dependant de proteines. Enfin, nous avons montre que la biodisponibilite d’autres micronutriments lipidiques (tocopherol, luteine, lycopene et beta-carotene), qui possedent des mecanismes d’absorption en commun avec le cholecalciferol (D3), etait en partie modulee par des polymorphismes mononucleotidiques (SNPs) dans des genes impliques dans le transport intestinal de ces micronutriments et dans le metabolisme des chylomicrons. L’objectif principal de cette etude etait donc d’identifier des SNPs associes avec la variabilite interindividuelle de la biodisponibilite de la D3. Materiel et methodes Trente-neuf hommes adultes en bonne sante ont ete genotypes a l’aide de puces a ADN genome entier. Ils ont consomme un repas contenant 5 g de D3 sous forme de supplement. La concentration en D3 et en calcifediol (25(OH)D) dans les chylomicrons plasmatiques a ete mesuree a intervalles de temps reguliers jusqu’a 8 h apres le repas. L’association entre des SNPs dans des genes impliques dans le metabolisme de la vitamine D et des lipides (61 genes candidats representant 3791 SNPs) et la reponse postprandiale en D3 dans les chylomicrons a ete analysee par regression des moindres carres partiels (regression PLS). Resultats La concentration postprandiale en D3 des chylomicrons a atteint son maximum 5,4 h apres le repas. Nous n’avons pas observe de variation significative de la concentration postprandiale en 25(OH)D des chylomicrons. La reponse postprandiale en D3 dans les chylomicrons presentait une forte variabilite interindividuelle (CV = 47 %). Cette reponse etait positivement correlee a la reponse postprandiale en triglycerides (r = 0,60, p Conclusion Chez des hommes adultes en bonne sante, on observe une forte variabilite interindividuelle de la biodisponibilite de la D3. Cette variabilite est associee avec une combinaison de SNPs dans des genes impliques dans le metabolisme de la vitamine D et des lipides.

Introduction et but de l’etude Les vitamines liposolubles jouent un role cle dans la prevention des pathologies oculaires, osseuses, neurovegetatives et cardiovasculaires. Cependant, leurs effets dependent de leur biodisponibilite, qui peut etre modulee par des interactions avec les composants du repas. Actuellement, la consommation de legumineuses est relancee comme source de proteines avec un faible impact environnemental. Or, leur plus grand apport est associe a une diminution du taux de cholesterol et de triglycerides circulants [1] , suggerant un impact sur l’absorption des lipides et donc des vitamines liposolubles. Le but de cette etude est donc d’evaluer l’impact des legumineuses (lentilles, haricots blancs, haricots rouges, flageolets et pois chiches) et du type de preparation (cuisson menagere contre appertisation) sur la bioaccessibilite et l’absorption intestinale des vitamines A (et son precurseur, le β-carotene), D, E et K. Materiel et methodes Des digestions in vitro ont permis de comparer la bioaccessibilite des vitamines liposolubles (pourcentage de vitamines du repas retrouvees dans les micelles mixtes), lorsque celles-ci sont ingerees dans un repas type (steak hache avec huile) en presence ou non de legumineuses (pommes de terre contre legumineuses). Les micelles mixtes issues de ces digestions in vitro sont ensuite deposees sur des cellules intestinales humaines Caco-2 TC7 afin d’evaluer leur capacite a absorber les vitamines liposolubles. Resultats La bioaccessibilite des vitamines liposolubles et du β-carotene en fin de digestion diminuait en presence de legumineuses (−11 % a −70 %) par rapport au repas controle ( p p p p p Conclusion Ces resultats montrent que la presence de legumineuses dans un repas diminue la bioaccessibilite et l’absorption des vitamines liposolubles, et, que le mode de preparation est un parametre important. L’identification du ou des composes responsables de ces effets permettra de proposer des solutions adaptees, dans l’objectif de mieux formuler des produits a base de legumineuses sans degrader la qualite nutritionnelle du repas. Ces travaux sont egalement une premiere base d’etude pour des recommandations de regimes vegetariens.

International audience; ScopeThe ability of different plant sterols/stanols (PS) mixtures, which differed in the degree of B-ring saturation and aliphatic side chain structure and saturation, to reduce cholesterol (CH) micellarization was explored. Methods and resultsExperiments were performed using an in vitro digestion model, synthetic mixed micelles, and pure porcine pancreatic lipases. Sterols were measured by GC-FID. The ability of PS to reduce CH micellarization was dependent on the form of PS and on the type of delivery matrix (low-fat yogurt or olive oil). Long-chain PS esters delivered in the yogurt matrix, and medium chain PS esters delivered in olive oil provided the greatest reduction in CH micellarization. In yogurt, the ability to impair CH micellarization was inversely related (rho = -0.41, p < 0.0005) to PS melting point. In olive oil, the more hydrophobic PS mixtures, i.e. those rich in long-chain PS esters, had the lower ability to impair CH micellarization. ConclusionsDifferent forms of PS have a different ability to impair CH micellarization. This ability depends on the transfer efficiency of PS from the food matrix to the micelle, which in turn depends on the melting point and the hydrophobicity of PS and on the delivery food matrix.

International audience; Intestine is the gateway for newly absorbed tocopherols. This organ also plays a crucial role in cholesterol metabolism. Because tocopherols are known to impact cholesterol metabolism in the liver, we hypothesized that tocopherols could also modulate cholesterol metabolism in the intestine. This study aimed to verify this hypothesis and to unveil the mechanisms involved, using Caco-2 cells as a model of the human intestinal cell. Both α- and γ-tocopherol significantly (P

Purpose Vitamin E (VE) is essential for human health and may play a role in the aetiology of cardiovascular diseases. However, its absorption efficiency is widely variable. This high interindividual variability is assumed to be due to both dietary and genetic factors. Several polymorphisms have been identified but existing studies have so far focused on single SNPs that only explained a minor fraction of the variability of such a complex phenotype. This study thus aimed to identify a combination of SNPs that could explain a significant part of the variability in VE bioavailability. Methods Thirty-eight healthy male volunteers consumed a meal containing a VE supplement (134 mg a-tocopheryl acetate). Volunteers were genotyped using whole-genome microarrays. a-tocopherol (TOL) concentration was measured in plasma chylomicrons (CM) isolated at regular time intervals over 8 h postprandially. The association of SNPs in or near candidate genes (59 genes representing 4475 SNPs) with the postprandial CM TOL response was assessed by partial least squares regression. Results The postprandial CM TOL response to the meal was highly variable (CV of 81%). Data obtained allowed us to generate a validated significant model (P=1.8.10-8) that included 28 SNPs in 11 genes (ABCA1, ABCG1, APOB, BET1, IRS1, LIPC, NAT2, PNLIP, SLC10A2, SREBF2, ZNF664). This model explained 82% of the variance and allowed us to accurately predict a subject’s VE absorption (Spearman Rho=85% between the measured and predicted VE response). For all these SNPs, univariate analysis showed that subjects who bore different genotypes exhibited a significantly different VE absorption. Conclusions The ability to respond to VE appears to be at least in part genetically determined. A combination of SNPs in 11 genes related to both VE and CM metabolism can explain a large part of the variability in VE absorption in males. These results could allow a better design of future clinical trials aiming at studying the association of VE supplementation with the prevention of cardiovascular diseases.

BACKGROUND: The bioavailability of β-carotene, the main dietary provitamin A carotenoid, varies among individuals. It is not known whether this variability can affect long-term β-carotene, and hence vitamin A, status. OBJECTIVES: We hypothesized that variations in genes involved in β-carotene absorption and postprandial metabolism could at least partially explain the high interindividual variability in β-carotene bioavailability. Thus, the main objectives of this study were to identify associated single-nucleotide polymorphisms (SNPs), and to estimate whether populations with different allele frequencies at these SNPs could have different abilities to absorb provitamin A carotenoids. METHODS: In this single-group design, 33 healthy, nonobese adult men were genotyped with the use of whole-genome microarrays. After an overnight fast, they consumed a test meal containing 100 g tomato puree providing 0.4 mg β-carotene. The postprandial plasma chylomicron β-carotene concentration was then measured at regular time intervals over 8 h. Partial least squares (PLS) regression was used to identify the best combination of SNPs in or near candidate genes (54 genes representing 2172 SNPs) that was associated with the postprandial chylomicron β-carotene response (incremental β-carotene area-under-the-curve concentration over 8 h in chylomicrons). RESULTS: The postprandial chylomicron β-carotene response was highly variable (CV = 105%) and was positively correlated with the fasting plasma β-carotene concentration (r = 0.78; P < 0.0001). A significant (P = 6.54 × 10(-3)) multivalidated PLS regression model, which included 25 SNPs in 12 genes, explained 69% of the variance in the postprandial chylomicron β-carotene response, i.e., β-carotene bioavailability. CONCLUSIONS: Interindividual variability in β-carotene bioavailability appears to be partially modulated by a combination of SNPs in 12 genes. This variability likely affects the long-term blood β-carotene status. A theoretic calculation of β-carotene bioavailability in 4 populations of the international HapMap project suggests that populations with different allele frequencies in these SNPs might exhibit a different ability to absorb dietary β-carotene. This trial was registered at clinicaltrials.gov as NCT02100774.

International audience; The intake of tomatoes and tomato products, which constitute the main dietary source of the red pigment Lycopene (LYC), has been associated with a reduced risk of prostate cancer and cardiovascular disease, suggesting a protective role of this carotenoid. However, LYC bioavailability displays high interindividual variability. This variability may lead to varying biological effects following LYC consumption. Based on recent results obtained with two other carotenoids, we assumed that this variability was due, at least in part, to several single nucleotide polymorphisms (SNPs) in genes involved in LYC and lipid metabolism. Thus, we aimed at identifying a combination of SNPs significantly associated with the variability in LYC bioavailability. In a postprandial study, 33 healthy male volunteers consumed a test meal containing 100 g tomato puree, which provided 9.7 mg all-trans LYC. LYC concentrations were measured in plasma chylomicrons (CM) isolated at regular time intervals over 8 h postprandially. For the study 1885 SNPs in 49 candidate genes, i.e., genes assumed to play a role in LYC bioavailability, were selected. Multivariate statistical analysis (partial least squares regression) was used to identify and validate the combination of SNPs most closely associated with postprandial CM LYC response. The postprandial CM LYC response to the meal was notably variable with a CV of 70%. A significant (P.-0.037) and validated partial least squares regression model, which included 28 SNPs in 16 genes, explained 72% of the variance in the postprandial CM LYC response. The postprandial CM LYC response was also positively correlated to fasting plasma LYC concentrations (r=0.37, P< 0.05). The ability to respond to LYC is explained, at least partly, by a combination of 28 SNPs in 16 genes. Interindividual variability in bioavailability apparently affects the long-term blood LYC status, which could ultimately modulate the biological response following LYC supplementation.

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International audience; Both vitamin E (VE) consumption and blood VE status have been negatively associated with the incidence of degenerative diseases and some cancers. However, the response to VE supplementation is very variable among individuals. This could be due to interindividual variability in VE bioavailability, due, at least partly, to genetic variations in genes involved in VE metabolism. Thus, the main objective was to identify single nucleotide polymorphisms (SNPs) that may be involved in the interindividual variability in alpha-tocopherol (TOL) bioavailability. The postprandial chylomicron (CM) TOL response (area under the curve of the postprandial CM TOL concentration) to a TOL-rich meal was highly variable (coefficient of variation=81%; n=38). This response was positively correlated with the fasting plasma TOL concentration (r=0.5, p=0.004). A significant (p=1.8x10(-8)) partial least-squares regression model, which included 28 SNPs in 11 genes, explained 82% of this response. First evidence that the interindividual variability in TOL bioavailability is, at least partly, modulated by a combination of SNPs. TOL bioavailability is, at least partly, modulated by genetic variations that can affect long-term TOL status. This allows us to propose a new hypothesis that links the biological response to VE supplementation with one's individual genetic characteristics.

International audience; The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption.

Introduction et but de l’étude: La carence en vitamine A (VA) constitue un problème majeur de santé publique, essentiellement dans les pays en développement où elle cause le décès de plus de 600 000 enfants âgés de 1 à 5 ans chaque année. Plus de 80% des enfants entre 1 et 5 ans reçoivent des suppléments de VA préformée (rétinyl acétate) mais l’efficacité de cette stratégie est à présent remise en question. La consommation de plantes locales riches en caroténoïdes provitaminiques (α-, β-carotène et β-cryptoxanthine essentiellement), qui permet de fournir des apports réguliers en VA à des doses physiologiques, constitue une stratégie alternative. Or la biodisponibilité et la conversion en VA des caroténoïdes provitaminiques sont faibles et très variables et l’effet de cette variabilité sur le statut à long terme en β-carotène (βC), et donc en VA, n’est pas connu. Les objectifs de cette étude étaient donc d’identifier des polymorphismes mononucléotidiques (SNPs) impliqués dans la variabilité interindividuelle de la biodisponibilité du βC et de calculer si des populations avec des fréquences alléliques différentes à ces SNPs pourraient avoir des capacités d’absorption du βC différentes.Matériel et méthodes: Trente trois hommes adultes en bonne santé ont été génotypés à l’aide de puces à ADN génome entier. Ils ont consommé un repas contenant 100 g de purée de tomate qui comprenait 0,4 mg de βC. La concentration plasmatique en βC dans les chylomicrons a été mesurée à intervalles de temps réguliers jusqu’à 8h après le repas. L’association entre des SNPs dans des gènes impliqués dans le métabolisme du βC et des lipides (54 gènes candidats représentant 2172 SNPs) et la réponse postprandiale en βC dans les chylomicrons a été analysée par régression des moindres carrés partiels (PLS regression), une approche statistique multivariée.Résultats et Analyse statistique: La réponse postprandiale en βC dans les chylomicrons présentait une forte variabilité (CV=105%). Cette réponse était positivement corrélée à la concentration plasmatique à jeun en βC (r=0,78; p

Background: Lutein accumulates in the macula and brain, where it is assumed to play physiologic roles. The bioavailability of lutein is assumed to display a high interindividual variability that has been hypothesized to be attributable, at least partly, to genetic polymorphisms. Objectives: We characterized the interindividual variability in lutein bioavailability in humans, assessed the relation between this variability and the fasting blood lutein concentration, and identified single nucleotide polymorphisms (SNPs) involved in this phenomenon. Design: In a randomized, 2-way crossover study, 39 healthy men consumed a meal that contained a lutein supplement or the same meal for which lutein was provided through a tomato puree. The lutein concentration was measured in plasma chylomicrons isolated at regular time intervals over 8 h postprandially. Multivariate statistical analyses were used to identify a combination of SNPs associated with the postprandial chylomicron lutein response (0‐8-h area under the curve). A total of 1785 SNPs in 51 candidate genes were selected. Results: Postprandial chylomicron lutein responses to meals were very variable (CVof 75% and 137% for the lutein-supplement meal and the meal with tomato-sourced lutein, respectively). Postprandial chylomicron lutein responses measured after the 2 meals were positively correlated (r = 0.68, P , 0.0001) and positively correlated to the fasting plasma lutein concentration (r = 0.51, P , 0.005 for the lutein-supplement‐containing meal). A significant (P = 1.9 3 10 24 ) and validated partial least-squares regression model, which included 29 SNPs in 15 genes, explained most of the variance in the postprandial chylomicron lutein response. Conclusions: The ability to respond to lutein appears to be, at least in part, genetically determined. The ability is explained, in large part, by a combination of SNPs in 15 genes related to both lutein and chylomicron metabolism. Finally, our results suggest that the ability to respond to lutein and blood lutein status are related. This trial was registered at clinicaltrials.gov as NCT02100774. Am J Clin Nutr doi: 10.3945/ajcn.114.085720.

SNPs involved in interindividual variability in chylomicron triacylglycerol response to dietary fat play a significant role in interindividual variability in chylomicron lutein response to dietary lutein.. 17. International Symposium on Carotenoids

International audience; Food fortification is a strategy to overcome vitamin A deficiency in developing countries. Our aim was to investigate the involvement of the bovine milk protein beta-lactoglobulin (beta-Lg), a potential retinoid carrier, in vitamin A absorption. In vivo experiments were conducted by force-feeding mice with retinol or beta-carotene associated with either beta-Lg or oil-in-water emulsion, with subsequent determination of both vitamin A intestinal mucosa and plasma contents. Caco-2 cells were then used to investigate the mechanisms of vitamin A uptake when delivered by either beta-Lg or mixed micelles. We showed that beta-Lg was as efficient as emulsion to promote beta-carotene, but not retinol, absorption in mice. Similar results were obtained in vitro. Interestingly, an inhibitor of the Scavenger Receptor Class B Type I significantly decreased the uptake of micellar beta-carotene but not that of beta-carotene bound to beta-Lg. Overall, we showed that beta-Lg would be a good vector for beta-carotene food fortification.

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International audience; We have recently shown that vitamin D-3 (cholecalciferol) absorption is not a simple passive diffusion but involves cholesterol transporters. As free fatty acids (FAs) modulate cholesterol intestinal absorption and metabolism, we hypothesized that FAs may also interact with vitamin D absorption. Effects of FAs were evaluated at different levels of cholecalciferol intestinal absorption. First, the physicochemical properties of micelles formed with different FAs were analyzed. The micelles were then administered to human Caco-2 cells in culture to evaluate FA effects on (i) cholecalciferol uptake and basolateral efflux and (ii) the regulation of genes coding proteins involved in lipid absorption process. Micellar electric charge was correlated with both FA chain length and degree of unsaturation. Long-chain FAs at 500 mu M in mixed micelles decreased cholecalciferol uptake in Caco-2 cells. This decrease was annihilated as soon as the long-chain FAs were mixed with other FAs. Oleic acid significantly improved cholecalciferol basolateral efflux compared to other FAs. These results were partly explained by a modulation of genes coding for lipid transport proteins such as Niemann-pick C1-like 1 and scavenger receptor class B type I. The data reported here show for the first time that FAs can interact with cholecalciferol intestinal absorption at different key steps of the absorption process. Cholecalciferol intestinal absorption may thus be optimized according to oil FA composition. (c) 2013 Elsevier Inc. All rights reserved.

The xanthophylls lutein and zeaxanthin probably play a role in visual function and may participate in the prevention of age-related eye diseases. Although a minimum amount of TAG is required for an optimal bioavailability of these carotenoids, the effect of the type of TAG fatty acids (FA) is less clear. The aim was to assess the effect of the type of TAG FA on bioavailability of these xanthophylls. A total of three complementary models were used: anin vitrodigestion model to study bioaccessibility, Caco-2 cells to study uptake efficiency and orally administered rats to studyin vivobioavailability. Results showed that lutein and zeaxanthin bioaccessibility was greater (about 20–30 %, PP

International audience; Consumption of phytosterols is a nutritional strategy to reduce cholesterol absorption, but the efficacy of various phytosterol intake modalities remains uncertain. The main objective was to investigate the effects of phytosterol esters (PE) provided either as a spread (dispersed in fat) during a mixed meal or as a minidrink (micro-dispersed in liquid form) after a meal. In a randomized, single-blinded crossover design, 12 healthy intubated volunteers tested three different liquid meal sequences with and without PE. The liquid meal (500 mL, Fortisip) contained an oral dose (80 mg) of deuterium-enriched cholesterol (D7C). The intubation was stopped at 240 min, and the fate of sterols was determined in the different phases of duodenal content samples as function of time. A second solid fat-containing meal without sterols was consumed at 270 min. D7C was quantified in chylomicrons and plasma for 8 h. The conditions tested were as follows: (1) no PE added (control), (2) PE in a spread added into a liquid meal (PE-spread meal) and (3) PE given 30 min after a liquid meal as 100-g yoghurt drink (PE-minidrink meal). Addition of PE decreased the incorporation of cholesterol into the duodenum aqueous phase including micelles. PE added as a spread or as a minidrink significantly and comparably lowered meal cholesterol occurrence in chylomicrons (-40 % for PE-spread and -54 % for PE-minidrink, p < 0.0001) compared with the control meal. PE either dispersed in fat during a meal or micro-dispersed in a liquid form after a meal resulted in a markedly reduced occurrence of meal-derived cholesterol in the circulation at a comparable extent.

International audience; Scope: Adequate vitamin D status is necessary and beneficial for health, although deficiency and insufficiency are very common. As cholecalciferol (vitamin D3) structure is close to cholesterol structure, we hypothesized that phytosterols, frequently used to decrease cholesterol, intestinal absorption and consequently to reduce hypercholesterolemia, may also interact with cholecalciferol absorption. Methods and results: β-Sitosterol effect on cholecalciferol postprandial response was first assessed in mice. We then evaluated the effect of different sterols on (i) cholecalciferol micellar incorporation, (ii) cholecalciferol apical uptake and (iii) basolateral efflux in vitro or ex vivo. In mice, cholecalciferol bioavailability was 15-fold lower in the presence of β-sitosterol (p

International audience; Phytosterols (plant sterols and stanols) can lower intestinal cholesterol absorption, but the complex dynamics of the lipid digestion process in the presence of phytosterol esters (PEs) are not fully understood. We performed a clinical experiment in intubated healthy subjects to study the time course of changes in the distribution of all lipid moieties present in duodenal phases during 4 h of digestion of meals with 3.2 g PE (PE meal) or without (control meal) PE. In vitro experiments under simulated gastrointestinal conditions were also performed. The addition of PE did not alter triglyceride (TG) hydrolysis in the duodenum or subsequent chylomicron TG occurrence in the circulation. In contrast, cholesterol accumulation in the duodenum aqueous phase was markedly reduced in the presence of PE (-32%, P < 0.10). In vitro experiments confirmed that PE reduces cholesterol transfer into the aqueous phase. The addition of PE resulted in a markedly reduced presence of meal-derived hepta-deuterated cholesterol in the circulation, i.e., in chylomicrons (-43%, PE meal vs. control; P < 0.0001) and plasma (-54%, PE meal vs. control; P < 0.0001). The present data show that addition of PE to a meal does not alter TG hydrolysis but displaces cholesterol from the intestinal aqueous phase and lowers chylomicron cholesterol occurrence in humans

International audience; Scope: It is assumed that vitamin D is absorbed by passive diffusion. However, since cholecalciferol (vitamin D(3) ) and cholesterol display similar structures, we hypothesized that common absorption pathways may exist. Methods and results: Cholecalciferol apical transport was first examined in human Caco-2 and transfected Human embryonic kidney (HEK) cells. Cholecalciferol uptake was then valuated ex vivo and in vivo, using either wild-type mice, mice overexpressing Scavenger Receptor class B type I (SR-BI) at the intestinal level or mice treated or not with ezetimibe. Cholecalciferol uptake was concentration-, temperature- and direction-dependent, and was significantly impaired by a co-incubation with cholesterol or tocopherol in Caco-2 cells. Moreover Block Lipid Transport-1 (SR-BI inhibitor) and ezetimibe glucuronide (Niemann-Pick C1 Like 1 inhibitor) significantly decreased cholecalciferol transport. Transfection of HEK cells with SR-BI, Cluster Determinant 36 and Niemann-Pick C1 Like 1 significantly enhanced vitamin D uptake, which was significantly decreased by the addition of Block Lipid Transport-1, sulfo-N-succinimidyl oleate (Cluster Determinant 36 inhibitor) or ezetimibe glucuronide, respectively. Similar results were obtained in mouse intestinal explants. In vivo, cholecalciferol uptake in proximal intestinal fragments was 60% higher in mice overexpressing SR-BI than in wild-type mice (p

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Interactions lipides-proteines membranaires : nouvelles donnees sur l’implication de SR-BI et CD36 dans l’absorption intestinale des lipides grâce la resonnance plasmonique de surface. 11. Journees Francophones de Nutrition (JFN)

Introduction et but de l’etude Une concentration postprandiale elevee en chylomicrons, qui sont essentiellement constitues de triglycerides (TG) issus des lipides nouvellement absorbes, est associee a un risque accru de developper des maladies cardiovasculaires et l’atherosclerose. On observe une forte variabilite interindividuelle de ce parametre, due en partie a des polymorphismes mononucleotidiques (SNPs) dans des genes impliques dans le metabolisme des lipides. Les etudes existantes ne se sont jusqu’ici interessees qu’a des SNPs analyses individuellement, et qui n’expliquent en consequence qu’une faible partie de cette variabilite. Dans cette etude, nous avons cherche a identifier une combinaison de SNPs associee a la variabilite de la reponse postprandiale en TG des chylomicrons suite a l’ingestion d’un repas riche en lipides. Materiel et methodes Trente-trois hommes adultes (IMC = 23,1 ± 0,4 kg/m 2 ) en bonne sante et non dyslipidemiques ont ete genotypes a l’aide de puces a ADN genome entier. Ils ont consomme a quatre occasions un repas riche en lipides et leur concentration plasmatique en TG des chylomicrons a ete mesuree a intervalles de temps reguliers jusqu’a 8h apres la consommation des repas. La moyenne des aires sous la courbe de cette concentration suite aux 4 repas a ete calculee afin d’evaluer la reponse postprandiale en TG des chylomicrons de chaque sujet, et de controler ainsi la variabilite intra-individuelle. Nous avons ensuite utilise une approche statistique multivariee, la regression des moindres carres partiels (PLS regression) , pour analyser l’association de plus de 6000 SNPs, dans 126 genes candidats lies au metabolisme des lipides, avec la variabilite de la reponse postprandiale en TG des chylomicrons. Resultats et Analyse statistique Nous avons identifie un modele valide ( p = 1,3 x 10 −7 ), comportant 42 SNPs dans 23 genes (ABCA1, APOA1, APOA5, APOB, BET1, CD36, COBLL1, ELOVL5, FRMD5, GPAM, INSIG2, IRS1, LDLR, LIPC, LPL, LYPLAL1, MC4R, NAT2, PARK2, SLC27A5, SLC27A6, TCF7L2, ZNF664) , qui permet d’expliquer la reponse postprandiale en TG des chylomicrons d’un sujet avec une erreur de 14 % seulement. Pour 39 de ces SNPs, les sujets possedant des genotypes differents presentaient une reponse postprandiale en TG des chylomicrons significativement differente (p-value corrigee Conclusion Ce modele predictif necessite d’etre valide dans d’autres groupes de sujets et sera certainement ameliore. Mais cette approche pourrait permettre de predire la reponse postprandiale en TG des chylomicrons avec un simple genotypage, ce qui serait nettement moins couteux que plusieurs tests de charge lipidiques. Les sujets a risque pourraient ainsi beneficier de conseils nutritionnels visant a diminuer leur risque cardiovasculaire en diminuant leurs apports en matieres grasses.

Introduction et but de l’etude Les recepteurs eboueurs tels que le Cluster Determinant 36 (CD36) et le Scavenger Receptor class B type I (SR-BI) jouent un role controverse dans le transport des lipides au travers de la bordure en brosse des enterocytes. Afin de mieux comprendre le fonctionnement de CD36 et de SR-BI, nous avons utilise la resonance plasmonique de surface permettant d’etudier les interactions entre ces transporteurs et de nombreux ligands lipidiques. Materiel et methodes Les boucles extracellulaires des transporteurs membranaires SR-BI et CD36 ont ete fixees sur des « Sensor chips » ou membranes NTA (nitrilotriacetic acid) par l’intermediaire d’une etiquette poly-histidine. Les interactions en temps reel entre les ligands proteines et les analytes lipidiques (allant de la molecule isolee a des structures plus physiologiques comme des micelles mixtes synthetiques) ont ete explorees grâce a l’utilisation d’un Biacore T100. Resultats et Analyse statistique Nous avons montre que les micelles imitant des conditions physiologiques, i.e. contenant diverses especes de lipides et de produits de digestion des lipides, sont necessaires a une association micellaire optimale a CD36 et SR-BI. Nous avons aussi montre que le contenu en cholesterol, phospholipides et en acides gras modulait significativement l’association et la dissociation des micelles aux recepteurs. En particulier, les fortes concentrations en phospholipides inhibaient l’association aux transporteurs (−53,8% et −74,4 % a 0,32 mM par rapport a 0,04 mM pour CD36 et SR-BI, respectivement, P Conclusion Nos donnees montrent pour la premiere fois que les recepteurs CD36 et SR-BI peuvent fixer efficacement les micelles mixtes et que la composition lipidique, et les proprietes physicochimiques des micelles sont des facteurs cles gouvernant les interactions micellaires avec les recepteurs eboueurs intestinaux.