Dietary inulin intake and age can significantly affect intestinal absorption of calcium and magnesium in rats: a stable isotope approach

BACKGROUND: previous studies have shown that non-digestible inulin-type fructan intake can increase intestinal mineral absorption in both humans and animals. However, this stimulatory effect on intestinal absorption may depend on experimental conditions such as duration of fermentable fiber intake, mineral diet levels and animals' physiological status, in particular their age. OBJECTIVES: the aim of this study was to determine the effect of inulin intake on Ca and Mg absorption in rats at different age stages. METHODS: eighty male Wistar rats of four different ages (2, 5, 10 and 20 months) were randomized into either a control group or a group receiving 3.75% inulin in their diet for 4 days and then 7.5% inulin for three weeks. The animals were fed fresh food and water ad libitum for the duration of the experiment. Intestinal absorption of Ca and Mg was determined by fecal monitoring using stable isotopic tracers. Ca and Mg status was also assessed. RESULTS: absorption of Ca and Mg was significantly lower in the aged rats (10 and 20 mo) than in the young and adult rat groups. As expected, inulin intake increased Ca and Mg absorption in all four rat groups. However, inulin had a numerically greater effect on Ca absorption in aged rats than in younger rats whereas its effect on Mg absorption remained similar across all four rat age groups. CONCLUSION: the extent of the stimulatory effect of inulin on absorption of Ca may differ according to animal ages. Further studies are required to explore this effect over longer inulin intake periods, and to confirm these results in humans

Comparison of lycopene and tomato effects on biomarkers of oxidative stress in vitamin E deficient rats

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceBACKGROUND: Cohort studies suggested that individuals with higher intake of tomatoes and tomato products have a lower risk of degenerative diseases. Lycopene, an antioxidant and antiproliferative carotenoid, has been hypothesized to be responsible for the health benefits of tomatoes. However, studies demonstrated a higher potential of tomatoes compared to lycopene to reduce oxidative stress or carcinogenesis. AIM OF THE STUDY: Our study aimed at distinguishing lycopene effect from that of tomato on oxidative stress, by using yellow tomato, a tomato variety devoid of lycopene. METHODS: Effects of feeding with none (control), 16% freeze-dried yellow tomato (YT), 16% freeze-dried red tomato (RT) or 0.05% lycopene beadlets (LB) were compared in a rat model with mild oxidative stress induced by low vitamin E diet (LVED). Four groups of 10 rats were fed ad libitum for 6 weeks. Physiological parameters such as ingesta, body, spleen and liver weights, cholesterol and triglycerides (TG) levels were assessed. Lycopene and vitamin E concentrations and oxidative stress biomarkers were measured in the plasma and/or liver and/or heart tissue of the rats. RESULTS: RT, YT, and LB had no effect on rats' ingesta, body and spleen weights. RT, YT and LB had no effect on plasma cholesterol concentration. RT decreased TG level compared to control, YT and LB (P < 0.05). Rats fed RT or LB accumulated lycopene in plasma in contrast with rats fed YT. Heart level of thiobarbituric reactive species (TBARS) in rats fed RT or YT was lower than that in the control and the LB fed rats (P < 0.05). Despite similar concentrations of lycopene in plasma and liver, rats fed LB showed a significantly higher heart level of TBARS than rats fed tomatoes. RT increased erythrocyte superoxide dismutase (eSOD) activity compared with LB and nitric oxide (NO) level compared with control and LB. LB decreased ferric reducing ability of plasma (FRAP) level compared with control, RT and LB (P < 0.05). CONCLUSION: Our study showed for the first time that tomatoes, containing or not containing lycopene, have a higher potential than lycopene to attenuate and or to reverse oxidative stress-related parameters in a mild oxidative stress context

Digestive stability of xanthophylls exceeds that of carotenes as studied in a dynamic in vitro gastrointestinal system

Supplemental Material can be found at: http://jn.nutrition.org/cgi/content/full/jn.108.103655/DC1 Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceEpidemiological studies have suggested that high consumption of tomato products is associated with a lower risk for chronic diseases. To exert their health effect, the phytochemicals of tomatoes have to be bioavailable and therefore it implies their stability through the digestion process. Here, we assessed the digestive stability of the red-pigmented lycopene and other carotenoids brought in nutritional quantity within different food matrixes, using the TNO gastrointestinal tract model (TIM). This multicompartmental dynamic system accurately reproduces the main parameters of gastric and small intestinal digestion in human. In vitro digestions of a standard meal containing red tomato (RT), yellow tomato (devoid of lycopene), or lycopene beadlets were performed. Zeaxanthin and lutein were stable throughout artificial digestions, whereas beta-carotene and all-trans lycopene were degraded (similar to 30 and 20% loss at the end of digestion, respectively) in the jejunal and ileal compartments. The recovery of beta-carotene in the digesta of the RT meal was significantly lower than that in the yellow one, showing a food matrix effect. In the same way, until 180 min of digestion, the recovery percentages of all-trans lycopene from RT were significantly lower than those issued from the supplement. Isomeric conformation also influenced the stability of carotenoids, 5-cis lycopene being the most stable isomer followed by all-trans and 9-cis. No trans-cis isomerization of lycopene occurred in the TIM. By using a relevant dynamic in vitro system, this study allowed us to gain further insight into the parameters influencing the digestive stability of carotenoids, and therefore their bioavailability, in humans

Stable isotopes in studies of intestinal absorption, exchangeable pools and mineral status: The example of magnesium

International audienceMagnesium (Mg) is a biologically essential mineral and Mg deficiency is known to lead to severe biochemical and symptomatic disorders. Radioactive isotopes and, more recently, stable isotopes have been used as research tools to determine intestinal Mg absorption in humans and animals under different nutritional and physiological conditions. Mg isotopes are given orally or orally plus intravenously and analysed in faeces and/or in plasma and urine in order to calculate intestinal Mg absorption and possibly endogenous Mg excretion. Mg isotopes have been used to assess exchangeable pools of Mg under nutritional and physiopathological conditions. Mg isotopes are given intravenously and are analysed in plasma and urine to calculate the size and half-life of the various Mg exchangeable pools. More recently, in vitro isotopic tests have been developed to study the need of cells for Mg in different nutritional and genetic conditions. Whole blood is incubated with Mg isotopes and isotopic blood cell enrichment is measured, which reflects the avidity of cells for Mg and thus its initial status. This paper is a report on the use of stable Mg isotopes and their advantages in these different fields of Mg absorption and metabolism. The studies available have clearly demonstrated that stable isotopes provide a useful research tool for determining intestinal Mg absorption, and represent a precious research tool for the study of Mg metabolism and the assessment of Mg status

Mécanismes de la lymphopénie radio-induite et implications thérapeutiques

International audienceLa lymphopénie radio-induite est fréquente et peut être profonde et durable. Bien que les lymphocytes soient connus depuis longtemps comme des cellules très radiosensibles, la lymphopénie radique est mal caractérisée. La lymphopénie radio-induite semble affecter différemment les sous-populations de lymphocytes et semble être influencée par les modalités de radiation. La profondeur et la durée de la lymphopénie sont variables selon la localisation de l’irradiation et les volumes de traitement. La lymphopénie radio-induite a été associée à un pronostic plus défavorable dans plusieurs types de tumeurs. Une connaissance plus approfondie de la lymphopénie radio-induite pourrait amener à repenser les modalités de la radiothérapie et à des approches pour restaurer le taux de lymphocytes

Impact of lymphopenia on efficacy of nivolumab in head and neck cancer patients

International audienceAbstractIntroductionLymphopenia has been correlated with poorer survival in patients with metastatic cancers treated with anti-PD-1 immunotherapy. Treatments such as chemotherapy, surgery or radiotherapy can induce lymphopenia. Radiation-induced lymphopenia is common and prolonged in head and neck cancer (HNSCC) patients. We evaluated the impact of lymphopenia, on efficacy of anti PD-1 nivolumab immunotherapy in HNSCC patients.MethodsA multicenter retrospective study included consecutive patients treated with nivolumab for recurrent/metastatic (R/M) HNSCC between January 2017 and June 2019. Lymphopenia was defined as lymphocyte counts below 1000 cells/mm3 upon initiation of nivolumab. Logistical regression was performed on factors associated with lymphopenia and ROC analyses assessed association between lymphopenia and survival.Resultsmedian age was 65. Of the 100 included patients, 60% had been treated by surgery, 67% had had first-line chemotherapy, and 89% loco-regional radiotherapy, 65% had concurrent chemotherapy with radiotherapy. Lymphopenia occurred in 56 (56%) patients upon initiation of nivolumab, with 29 (29%) patients having radiation-related lymphopenia. Prior locoregional radiotherapy was the only factor associated with lymphopenia upon initiation of nivolumab by logistical regression (OR 0.144 [0.029–0.706], p − 0.017). Lymphopenia upon initiation of nivolumab did not affect progression-free survival (PFS) (p − 0.815), overall survival (OS) (p − 0.783) or disease control rate (DCR) (p − 0.125). Locoregional symptomatology (HR − 2.37 [1.24–4.54], p − 0.009), metastatic symptomatology (HR − 4.74 [2.21–10.15], and persistent lymphopenia under nivolumab (HR 3.96 [1.19–13.17] p − 0.034) were associated with poorer OS in multivariate analysis.ConclusionsLymphopenia upon initiation of nivolumab was not associated with poorer survival in R/M HNSCC patients, but persistence of lymphopenia during immunotherapy might be a prognostic marker of patient survival

Optimisation de la prise d’essai pour la détermination de profils métaboliques plasmatiques chez des modèles animaux.

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Polyunsaturated fatty acids prevent myosteatosis and lipotoxicity

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