Etat des lieux des digestats en France et de leur valeur agronomique

International audienceIn France, as in several countries worldwide, anaerobic digestion is extensively promoted for the management of organic wastes from various origins like sludge from wastewater treatment plants, food-industry, agriculture (including animal manure and culture residues) and municipal solid waste (including household and green waste). Despite this strong promotion, the status of the digestate remains a problem since it is still considered as a waste by French regulation and can be used only for spreading on land or has to be transformed by composting. Since digestate composition may differ depending on the origin of the methanised substrates and since several different post-processing steps can be used to change its physico-chemical characteristics, we did a review of the different studies realized so far in France concerning anaerobic digestion main waste streams, digestates composition and agronomical value

Leptin Modulates the Expression of miRNAs-Targeting POMC mRNA by the JAK2-STAT3 and PI3K-Akt Pathways

International audienceThe central control of energy balance involves a strongly regulated neuronal network within the hypothalamus and the brainstem. In these structures, pro-opiomelanocortin (POMC) neurons are known to decrease food intake and to increase energy expenditure. Thus, leptin, a peripheral signal that relays information regarding body fat content, modulates the activity of POMC neurons. MicroRNAs (miRNAs) are short non-coding RNAs of 22-26 nucleotides that post-transcriptionally interfere with target gene expression by binding to their mRNAs. It has been demonstrated that leptin is able to modulate the expression of miRNAs (miR-383, miR-384-3p, and miR-488) that potentially target POMC mRNA. However, no study has identified the transduction pathways involved in this effect of leptin on miRNA expression. In addition, miRNAs targeting POMC mRNAs are not clearly identified. In this work, using in vitro models, we have identified and confirmed that miR-383, miR-384-3p, and miR-488 physically binds to the 3 untranslated (3 UTR) regions of POMC mRNA. Importantly, we show that leptin inhibits these miRNAs expression by different transduction pathways. Taken together, these results allowed us to highlight the miRNA involvement in the regulation of POMC expression downstream of the leptin signaling and satiety signal integration

Vitamin D Supplementation Improves Adipose Tissue Inflammation and Reduces Hepatic Steatosis in Obese C57BL/6J Mice

International audienceThe beneficial effect of vitamin D (VD) supplementation on body weight gain limitation and inflammation has been highlighted in primary prevention mice models, but the long-term effect of VD supplementation in tertiary prevention has never been reported in obesity models. The curative effect of VD supplementation on obesity and associated disorders was evaluated in high-fat- and high-sucrose (HFS)-fed mice. Morphological, histological, and molecular phenotype were characterized. The increased body mass and adiposity caused by HFS diet as well as fat cell hypertrophy and glucose homeostasis were not improved by VD supplementation. However, VD supplementation led to a decrease of HFS-induced inflammation in inguinal adipose tissue, characterized by a decreased expression of chemokine mRNA levels. Moreover, a protective effect of VD on HFS-induced hepatic steatosis was highlighted by a decrease of lipid droplets and a reduction of triglyceride accumulation in the liver. This result was associated with a significant decrease of gene expression coding for key enzymes involved in hepatic de novo lipogenesis and fatty acid oxidation. Altogether, our results show that VD supplementation could be of interest to blunt the adipose tissue inflammation and hepatic steatosis and could represent an interesting nutritional strategy to fight obesity-associated comorbidities

All-trans-retinoic acid represses chemokine expression in adipocytes and adipose tissue by inhibiting 1 NF-κB signaling 2 3

International audienceAn effect of the Vitamin A metabolite all-trans-retinoic acid (ATRA) on body weight regulation and adiposity has been described, but little is known about its impact on obesity-associated inflammation. Our objective was to evaluate the overall impact of this metabolite on inflammatory response in human and mouse adipocytes, using high-throughput methods, and to confirm its effects in a mouse model. ATRA (2 μM for 24 h) down-regulated the mRNA expression of 17 chemokines in human adipocytes, and limited macrophage migration in a TNFα-conditioned 3 T3-L1 adipocyte medium (73.7%, P<.05). These effects were confirmed in mice (n=6–9 per group) subjected to oral gavage of ATRA (5 mg/kg of body weight) and subsequently injected intraperitoneally with lipopolysaccharide. In this model, both systemic and adipose levels of inflammatory markers were reduced. The antiinflammatory effect of ATRA was associated with a reduction in the phosphorylation levels of IκB and p65 (~50%, P<.05), two subunits of the NF-κB pathway, probably mediated by PGC1α, in 3 T3-L1 adipocytes. Taken together, these results show a significant overall antiinflammatory effect of ATRA on proinflammatory cytokine and chemokine production in adipocyte and adipose tissue and suggest that ATRA supplementation may represent a strategy of preventive nutrition to fight against obesity and its complications

Combined Beneficial Effect of Voluntary Physical Exercise and Vitamin D Supplementation in Diet-induced Obese C57BL/6J Mice

International audiencePurpose Physical exercise (PE) combined with nutritional approaches has beneficial effects that are widely advocated to improve metabolic health. Here we used voluntary PE together with vitamin D (VD) supplementation, which has already shown beneficial effects in primary and tertiary prevention in obese mice models, to study their combined additive effects on body weight management, glucose homeostasis, metabolic inflammation, and liver steatosis as key markers of metabolic health. Methods Ten-week-old male C57BL/6J mice were fed a high-fat/sucrose (HFS) diet for 10 wk, then assigned to a 15-wk intervention period with PE, VD supplementation, or both PE and VD supplementation. Morphological, histological, and molecular phenotype data were characterized. Results The HFS-induced increases in body mass, adiposity, and adipocyte hypertrophy were improved by PE but not by VD supplementation. The HFS-induced inflammation (highlighted by chemokines mRNA levels) in inguinal adipose tissue was decreased by PE and/or VD supplementation. Furthermore, the intervention combining PE and VD showed additive effects on restoring insulin sensitivity and improving hepatic steatosis, as demonstrated through a normalization of size and number of hepatic lipid droplets and triglyceride content and a significant molecular-level decrease in the expression of genes coding for key enzymes in hepatic de novo lipogenesis. Conclusions Taken together, our data show beneficial effects of combining PE and VD supplementation on obesity-associated comorbidities such as insulin resistance and hepatic disease in mice. This combined exercise-nutritional support strategy could prove valuable in obesity management programs

Combined Beneficial Effect of Voluntary Physical Exercise and Vitamin D Supplementation in Diet-induced Obese C57BL/6J Mice

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Combined Beneficial Effect of Voluntary Physical Exercise and Vitamin D Supplementation in Diet-induced Obese C57BL/6J Mice

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Lycopene and tomato powder supplementation similarly inhibit high-fat diet induced obesity, inflammatory response, and associated metabolic disorders

Several studies have linked the high intake of lycopene or tomatoes products with lower risk for metabolic diseases. The aim of the present study was to evaluate and to compare the effect of lycopene and tomato powder on obesity-associated disorders. METHODS AND RESULTS: Male C57BL/J6 mice were assigned into four groups to receive: control diet (CD), high fat diet (HFD), high fat diet supplemented with lycopene or with tomato powder (TP) for 12 weeks. In HFD condition, lycopene and TP supplementation significantly reduced adiposity index, organ, and relative organ weights, serum triglycerides, free fatty acids, 8-iso-prostaglandin GF2α and improved glucose homeostasis, but did not affect total body weight. Lycopene and TP supplementation prevented HFD-induced hepatosteatosis and hypertrophy of adipocytes. Lycopene and TP decreased HFD-induced proinflammatory cytokine mRNA expression in the liver and in the epididymal adipose tissue. The anti-inflammatory effect of lycopene and TP was related to a reduction in the phosphorylation levels of IκB, and p65, and resulted in a decrease of inflammatory proteins in adipose tissue. CONCLUSION: These results suggest that lycopene or TP supplementation display similar beneficial health effects that could be particularly relevant in the context of nutritional approaches to fight obesity-associated pathologies

Simple Fast Quantification of Cholecalciferol, 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D in Adipose Tissue Using LC-HRMS/MS

International audienceVitamin D metabolism is actively modulated in adipose tissue during obesity. To better investigate this process, we develop a specific LC-HRMS/MS method that can simultaneously quantify three vitamin D metabolites, i.e., cholecalciferol, 25-hydroxyvitamin D 3 (25(OH)D 3), and 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3) in a complex matrix, such as mouse adipose tissue and plasma. The method uses pretreatment with liquid-liquid or solid-phase extraction followed by derivatization using Amplifex ® reagents to improve metabolite stability and ionization efficiency. Here, the method is optimized by co-eluting stable isotope-labelled internal standards to calibrate each analogue and to spike biological samples. Intra-day and inter-day relative standard deviations were 0.8-6.0% and 2.0-14.4%, respectively for the three derivatized metabolites. The limits of quantification (LoQ) achieved with Amplifex ® derivatization were 0.02 ng/mL, 0.19 ng/mL, and 0.78 ng/mL for 1,25(OH) 2 D 3 , 25(OH)D 3 and cholecalciferol, respectively. Now, for the first time, 1,25(OH) 2 D 3 can be co-quantified with cholecalciferol and 25(OH)D 3 in mouse adipose tissue. This validated method is successfully applied to study the impact of obesity on vitamin D status in mice

Four days high fat diet modulates vitamin D metabolite levels and enzymes in mice

International audienceObesity is classically associated with low serum total and free 25(OH)D. Hypotheses have been advanced to explain this observation but mechanisms remain poorly understood, and notably priming events that could explain such association. We investigated the impact of short-term high fat (HF) diet to investigate early events occurring in vitamin D metabolism. Male C57BL/6J mice were fed with a control diet (control group) and HF diet for 4 days. HF fed mice displayed similar body weight to control mice but significantly increased adiposity, together with a decrease of free 25(OH)D concentrations, which could be explained at least in part by a decrease of Cyp2r1 and Cyp3a11 expression in the liver. An increase of 1,25(OH) 2 D concentration was also observed and could be explained by a decrease of Cyp24a1 expression observed in the kidney. In white adipose tissue (WAT), no modification of vitamin D metabolites quantity detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nevertheless, an increase of Cyp2r1 and Cyp27a1 mRNA expression and a decrease of Cyp27b1 mRNA expression could suggest a possible storage of 25(OH)D in WAT at long-term. Our data are supportive of an active role of HF diet in mediating a priming effect leading the well-established perturbation of the vitamin D metabolism associated with obesity, including a decrease of free 25(OH)D and modulation of expression of genes involved in vitamin D metabolism