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

NADPH oxidase activity is associated with cardiac osteopontin and pro-collagen type I expression in uremia.

International audienceCardiovascular disease is a frequent complication inducing mortality in chronic kidney disease (CKD) patients, which can be determined by both traditional risk factors and non-traditional risk factors such as malnutrition and oxidative stress. This study aimed to investigate the role of oxidative stress in uremia-induced cardiopathy in an experimental CKD model. CKD was induced in Sprague-Dawley rats by a 4-week diet supplemented in adenine, calcium and phosphorous and depleted in proteins. CKD was associated with a 3-fold increase in superoxide anion production from the NADPH oxidase in the left ventricle, but the maximal activity of mitochondrial respiratory chain complexes was not different. Although manganese mitochondrial SOD activity decreased, total SOD activity was not affected and catalase or GPx activities were increased, strengthening the major role of NADPH oxidase in superoxide anion output. Superoxide anion output was associated with enhanced expression of osteopontin (×7.7) and accumulation of pro-collagen type I (×3.7). To conclude, the increased activity of NADPH oxidase during CKD is associated with protein modifications which could activate a pathway leading to cardiac remodelling

Etude de l’effet d’un régime riche en huile de palme sur l’expression génétique des facteurs myogéniques

Un niveau élevé d'acides gras saturés (AGS) dans le sang a un effet délétère sur les muscles squelettiques en inhibant à la fois la régénération des fibres musculaires et la synthèse des protéines musculaires. Du fait de sa richesse en AGS, l’huile de palme est controversée. Cette étude avait pour objectif d’étudier l’effet d’un régime riche en huile de palme (brute et raffinée) sur l’expression des facteurs myogéniques dans le muscle de rats sédentaires et le comparer avec un régime riche en huile d’olive et en Lard. Quarante rats mâles Wistar ont été répartis en 5 groupes de 8 rats chacun : 1 groupe témoin et 4 groupes nourris par des régimes riches en graisse (HFD) contenant respectivement de l’huile de palme brute, de l’huile de palme raffinée, de l’huile d’olive et du lard. Après 12 semaines de régime, les rats ont été sacrifiés et les tissus prélevés L'expression de Pax7, Myf5, MyoD et MyoG a été évaluée par RT-qPCR dans les muscles gastrocnémiens. Aucune différence significative n’a été observée entre régime témoin et HFD concernant les expressions de Pax7, Myf5 et MyoG. L’expression de MyoD s’est avérée significativement plus élevée dans les animaux HFD (p=0,0004) par rapport au témoin ; en particulier dans le régime riche en huile d’olive par rapport aux autres régimes HFD (p=0,05). Aucune altération significative de l’expression des gènes des facteurs de régulation myogénique n’a été observée avec l’huile de palme sous ses 2 formes, brute et raffinée. En conclusion, l’huile de palme, malgré sa richesse en AGS, n’a pas d’effet délétère sur la régénération du muscle squelettique.Mots clés : Régime riche graisses, muscle squelettique, Pax7, Myf5, MyoD, MyoG

Les cardiolipides, des phospholipides clés pour la fonction mitochondriale. Relation avec les apports lipidiques et la physiopathologie

Le cardiolipide (CL) est un phospholipide exclusivement présent dans la membrane mitochondriale et joue un rôle clé dans plusieurs processus de bioénergétique mitochondriale, ainsi que dans la stabilité et la dynamique de la membrane mitochondriale. En raison de sa richesse en acides gras polyinsaturés (en particulier en acide linoléique), le CL est très sensible à l’attaque par les radicaux libres produits par la mitochondrie. L’oxydation du CL a des conséquences majeures sur le fonctionnement de la mitochondrie, en particulier la phosphorylationoxydative et la production d’ATP. Par ailleurs, les régimes alimentaires plus ou moins riches en graisses peuvent modifier la composition lipidique de la membrane mitochondriale, y compris la teneur en CL et sa composition en acides gras, et ces modifications peuvent par la suite altérer le fonctionnement de la mitochondrie. Or, les régimes alimentaires riches en graisses sont associés à la stéatose hépatique et à l’insulino-résistance, deux problèmes majeurs de santé publique. L’objectif de cet article est de faire le point sur les connaissances actuelles concernant le rôle du CL dans les pathologies nutritionnelles liées à une surcharge en lipides

Impact of high dietary lipid intake and related metabolic disorders on the abundance and acyl composition of the unique mitochondrial phospholipid, cardiolipin

Excessive dietary lipid intake, coupled with lack of exercise, are the major causes of the development and progression of metabolic syndrome features e. g. obesity, hepatic steatosis, insulin resistance, type 2 diabetes and cardiovascular diseases. These metabolic diseases are associated with both structural and functional alterations of mitochondria. Cardiolipin (CL) is a unique phospholipid that is almost exclusively localized in the mitochondrial inner membrane. Cardiolipin is at the heart of mitochondrial metabolism playing a key role in several processes of mitochondrial bioenergetics as well as in mitochondrial membrane stability and dynamics, and in many of the mitochondrial-dependent steps of apoptosis. Indeed, alterations to CL content and acyl chain profile have been associated with mitochondrial dysfunction in multiple tissues in Barth syndrome and in many other physio-pathological conditions. After a brief overview of the biological roles of CL, we highlight the consequences of lipid overload-related nutritional manipulations as well as related metabolic disorders on both CL content and its fatty acid composition in the major metabolic tissues, the heart, muscle and liver. The goal of this review is to fill a void in the CL literature concerning the effects of CL abundance and form that arise following high lipid supplementation and the related metabolic disorders

Effect of spirulina and silicon‐enriched spirulina on metabolic syndrome features, oxidative stress and mitochondrial activity in Zucker fatty rats

International audienceThe use of Spirulina platensis (Sp) as a functional food was suggested decades ago. Biological incorporation of Silicon (Si) into Sp increases its bioavailability for potential food supplement applications. This work aimed at determining the effects of Sp and Si-enriched Sp (Sp+Si) on metabolic syndrome features in Zucker fatty rats. Thirty Zucker fatty rats were divided into three groups and supplemented with placebo or Sp or Sp+Si croquettes for 12 weeks. Food consumption, glucose intolerance, hepatic steatosis, and mitochondrial and oxidative stress were determined. Zucker fatty rats exhibited several hepatic metabolic alterations as well as mitochondrial and oxidative stress perturbations. The intake of Sp increased plasma TG levels and decreased the hepatic NADPH oxidase activity and ameliorated transitorily the glucose intolerance. However, Si-spirulina does not appear to have more beneficial effects than spirulina alone. Other experiments with different species of rats/mice, different diets, or durations of diet intake should be undertaken to confirm or infirm these results. PRACTICAL APPLICATIONS: Glucose intolerance and hepatic steatosis, two major components of metabolic syndrome, are increasing and becomes a major public health issue. Use of Spirulina platensis (Sp) as a functional food was suggested as a protein-dense food source. Bioavailable silicon (Si) may be an essential nutrient for higher animals, including humans. Sp but not Sp+Si decreased liver NADPH oxidase activity and improved transitorily glucose tolerance. This is the first study where Sp and Sp+Si effect on glucose intolerance is reported in Zucker rat. Other experiments should be undertaken to confirm or infirm invalidate the beneficial effects of Sp+Si supplement in the metabolic syndrome features

Ecologie des systèmes alimentaires: Définition

National audienceL’écologie des systèmes alimentaires (SA) désigne une approche englobant l’agroécologie et la manière de se nourrir, de façon à prendre en compte les interdépendances entre l’environnement, l’alimentation et les filières. Fondée sur des approches holistiques, de type « one-health », cette approche interdisciplinaire en cours de construction permet d’identifier les interdépendances entre enjeux et processus qui se déroulent à différentes échelles d’espace et de temps...

The Dietary Total-Fat Content Affects the In Vivo Circulating C15:0 and C17:0 Fatty Acid Levels Independently.

Pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) have been described as dietary biomarkers of dairy-fat consumption, with varying degrees of reliability between studies. It remains unclear how the total amount of dietary fat, representing one of the main confounding factors in these biomarker investigations, affects C15:0 and C17:0 circulating concentrations independent of their relative intake. Additionally, it is not clear how changes in the dietary total-fat affects other fatty acids in circulation. Through two dietary studies with different total-fat levels but maintaining identical fatty acid compositions, we were able to see how the dietary total-fat affects the fatty acids in circulation. We saw that there was a statistically significant, proportionate, and robust decrease in the endogenous C15:0 levels with an increase in dietary total-fat. However, there was no significant change in the circulating C17:0 concentrations as the total-fat increased. To conclude, the dietary total-fat content and fat-type have a very complex influence on the relative compositions of circulating fatty acids, which are independent of the actual dietary fatty acid composition. Knowing how to manipulate circulating C15:0 and C17:0 concentrations is far-reaching in nutritional/pathological research as they highlight a dietary route to attenuate the development of metabolic disease (both by reducing risk and improving prognosis)