Challenges to determining whether DHA can protect against age-related cognitive decline

DHA, an omega-3 fatty acid, is an important constituent of brain membranes and has a key role in brain development and function. This review aims to highlight recent research on DHA’s role during age-related cognitive decline and Alzheimer’s disease. Animal and in vitro studies have provided some interesting mechanistic leads, especially on brain glucose metabolism, that may be involved in neuroprotection by DHA. However, results from human studies are more mitigated, perhaps due to changing DHA metabolism during aging. Recent innovative tools such as 13C-DHA for metabolic studies and 11C-DHA for PET provide interesting opportunities to study factors that affect DHA homeostasis during aging and to better understand whether and how to use DHA to delay or treat Alzheimer’s disease

Renforcer les conclusions issues de modèles écosystémiques par la prise en compte de l’incertitude dans les paramètres

Indices of ecological networks analysis (or ENA - "Ecological Network Analysis") are based on the outputs of ecosystem models to study the ecosystems’ structure and functioning and their ability to respond to perturbation. However, ecological conclusions derived from the calculation of these indices generally lack robustness. Indeed, for a given ecosystem, there is in most cases a single model synthesizing knowledge about this system. The different ENA indices are calculated from outputs of this single model, leading to only one value per index. It is from this single value and its comparison with those obtained for the same type of ecosystem that ecological conclusions are currently derived. This internship was designed to implement a procedure, based on existing Matlab codes and routines, to compute a set of values for ENA indices from the uncertainties of the input parameters of ecosystem models. The procedure developed has subsequently been applied to different ecosystems for which there were ecosystem models: on one side the continental shelf of the Bay of Biscay and on the other side estuaries of the French coastline. Ecological conclusions from previous works based on single values of ENA indices were revised following the application of the procedure developed in this internship.Les indices de l’analyse des réseaux écologiques (ou ENA - « Ecological Network Analysis ») sont calculés sur les sorties des modèles écosystémiques afin d’étudier la structure, le fonctionnement des écosystèmes et leur capacité à répondre à une perturbation. Cependant, les conclusions écologiques dérivées de la valeur de ces indices manquent généralement de robustesse. En effet, pour un écosystème donné, il existe dans de nombreux cas un modèle unique faisant la synthèse des connaissances sur ce système. Les différents indices ENA sont calculés à partir des sorties de ce modèle unique, aboutissant à une seule valeur par indice. C’est de cette valeur unique et de sa comparaison avec celles obtenues pour des écosystèmes de même type que les conclusions écologiques sont pour le moment dérivées. Ce stage avait pour but d’implémenter une procédure, sur la base de routines et codes existants sous le logiciel Matlab, afin de calculer un ensemble de valeurs pour les indices ENA à partir des incertitudes sur les paramètres d’entrée des modèles écosystémiques. La procédure développée a par la suite été appliquée à différents écosystèmes pour lesquels ils existaient des modèles écosystémiques : d’un côté le plateau continental du Golfe de Gascogne et de l’autre des estuaires de la façade maritime française. Les conclusions écologiques issues de travaux précédents se basant sur des valeurs uniques d’indices ENA ont été revues suite à l’application de la procédure développée au cours de ce stage

Approche structurelle versus fonctionnelle : une première comparaison entre les indicateurs de la directive cadre sur l'eau et les indices ENA pour les estuaires européens

International audienceThe implementation of the European Water Framework Directive (WFD) has led to the development of various biotic indices in order to assess the ecological status of aquatic ecosystems. These indices are mainly based on the structure of ecological communities. The main underlying assumption of such an approach is that structural features of selected ecological communities are representative of the ecological functioning of the ecosystem. In particular, the ecological status of transitional waters has to be assessed using fish-based indicators (FI) which are computed using observation data on species diversity and abundance. Concurrently, stability, maturity and resilience features of ecosystems are often discussed using indices provided by Ecological Network Analysis (ENA). ENA is not only based on structural elements of ecological communities but also on a functional description of the ecosystem centred on energy flows. However, to conclude on “whether some attribute of ecosystem networks might provide an appropriate and useful indicator of system performance” (Ulanowicz 2004), ENA approaches must be compared with other existing methods of assessing ecological quality (Christian et al., 2005). The purpose of this work is to discuss results of both approaches applied on 5 French estuarine areas

Approche structurelle versus fonctionnelle : une première comparaison entre les indicateurs de la directive cadre sur l'eau et les indices ENA pour les estuaires européens

International audienceThe implementation of the European Water Framework Directive (WFD) has led to the development of various biotic indices in order to assess the ecological status of aquatic ecosystems. These indices are mainly based on the structure of ecological communities. The main underlying assumption of such an approach is that structural features of selected ecological communities are representative of the ecological functioning of the ecosystem. In particular, the ecological status of transitional waters has to be assessed using fish-based indicators (FI) which are computed using observation data on species diversity and abundance. Concurrently, stability, maturity and resilience features of ecosystems are often discussed using indices provided by Ecological Network Analysis (ENA). ENA is not only based on structural elements of ecological communities but also on a functional description of the ecosystem centred on energy flows. However, to conclude on “whether some attribute of ecosystem networks might provide an appropriate and useful indicator of system performance” (Ulanowicz 2004), ENA approaches must be compared with other existing methods of assessing ecological quality (Christian et al., 2005). The purpose of this work is to discuss results of both approaches applied on 5 French estuarine areas

Influence of different intravenous lipid emulsions on growth, development and laboratory and clinical outcomes in hospitalised paediatric patients: A systematic review

Background & aims Fats in the form of lipid emulsions (LEs) are an integral part of intravenous nutrition. The fatty acid composition of different LEs varies. The exact composition of a LE may influence cell and tissue function and clinical outcome. Currently, it is not clear which LE might be best for paediatric patients. We conducted a systematic review of the effects of different intravenous LEs in hospitalised paediatric patients. Methods Randomised controlled trials published in a peer reviewed journal, written in the English language, and comparing two or more different intravenous LEs in hospitalised paediatric patients were included. Data on outcomes of relevance (growth, development, laboratory and clinical outcomes) were extracted, collated and interpreted. Results Thirty-one articles involving 1522 infants or children were included. Most outcomes were not affected by the nature of the LE used. LEs containing fish oil, a source of omega-3 fatty acids, improved outcome of retinopathy of prematurity, decreased liver cholestasis and increased blood omega-3 fatty acid levels. LEs containing olive oil increased blood oleic acid level and had a cholesterol lowering effect. Conclusion Blood fatty acids are influenced by the nature of the intravenous LE used in hospitalised paediatric patients. Most studies suggest limited differences in relevant laboratory or clinical outcomes or in growth in paediatric patients receiving different LEs, although several studies do find benefits from including fish oil or olive oil. There is a need for larger trials to fully evaluate the effects of the available LE types in hospitalised paediatric patients