Neurotrophic Effect of Fish-Lecithin Based Nanoliposomes on Cortical Neurons

Lipids play multiple roles in preserving neuronal function and synaptic plasticity, and polyunsaturated fatty acids (PUFAs) have been of particular interest in optimizing synaptic membrane organization and function. We developed a green-based methodology to prepare nanoliposomes (NL) from lecithin that was extracted from fish head by-products. These NL range between 100–120 nm in diameter, with an n-3/n-6 fatty acid ratio of 8.88. The high content of n-3 PUFA (46.3% of total fatty acid content) and docosahexanoic acid (26%) in these NL represented a means for enrichment of neuronal membranes that are potentially beneficial for neuronal growth and synaptogenesis. To test this, the primary cultures of rat embryo cortical neurons were incubated with NL on day 3 post-culture for 24 h, followed by immunoblots or immunofluorescence to evaluate the NL effects on synaptogenesis, axonal growth, and dendrite formation. The results revealed that NL-treated cells displayed a level of neurite outgrowth and arborization on day 4 that was similar to those of untreated cells on day 5 and 6, suggesting accelerated synapse formation and neuronal development in the presence of NL. We propose that fish-derived NL, by virtue of their n-3 PUFA profile and neurotrophic effects, represent a new innovative bioactive vector for developing preventive or curative treatments for neurodegenerative diseases

Monitorage biologique du traumatisé crânien sévère (étude préliminaire sur la place du dosage des 15-F2t-isoprostanes (8-isoprostaglandines) dans les microdialysats cérébraux)

Le traumatisme crânien constitue un problème de santé publique, par son incidence et le jeune âge des sujets atteints. L'apparition systématique de lésions cérébrales secondaires, surajoutées aux lésions initiales, complique l'évolution clinique. Pour freiner ces lésions secondaires, une prise en charge précoce et un monitorage optimal sont primordiaux. Des marqueurs biologiques, comme la protéine S-IOOb, sont utilisés comme marqueur pronostique et la microdialyse cérébrale constitue une technique novatrice d'échantillonnage du liquide extracellulaire au plus près des lésions. Cette technique permet d'isoler précocement des marqueurs reflétant les perturbations biochimiques rencontrés chez les patients cérébrolésés, telles que l'inflammation, l'excitotoxicité, la défaillance énergétique et le stress oxydant. La susceptibilité du cerveau aux radicaux libres et sa richesse en lipides placent le stress oxydant comme acteur majeur de la physiopathologie des lésions secondaires. La peroxydation lipidique aboutit à la production d'analogue des prostaglandines, les isoprostanes, aux effets bioactifs délétères et constituant un marqueur biologique du stress oxydant. Notre étude princeps dosant les 15-F2t-isoprostanes dans les microdialysats de trois patients traumatisés crâniens sévères par technique ELISA a permis d'en montrer la faisabilité. Ces résultats, couplés aux dosages de la protéine S-IOOb sérique et au lactate, pyruvate, glutamate et glucose issus des microdialysats, ont permis de dégager des profils biologiques évolutifs différents selon le devenir à court et moyen terme des patients. La faisabilité de cette étude encourage à poursuivre les investigations pour démontrer l'intérêt pronostique des 15-F2t-isoprostanes dans le monitorage biologique des traumatisés crâniens.NANCY1-SCD Medecine (545472101) / SudocSudocFranceF

Place du réseau de pharmaciens sentinelles de Lorraine dans le dispositif public de lutte contre les pharmacodépendances

NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocSudocFranceF

Implication de la phospholipase A2 cytoplamique dans la pathogénèse de la maladie d'Alzheimer

Les oligomères solubles de peptide Bêta-amyloïde (Ab) apparaissent comme les acteurs majeurs de la perte synaptique précoce observée au cours de la maladie d'Alzheimer. Notre équipe a précédemment montré que ces oligomères de peptide Ab activent la phospholipase A2 cytosolique (cPLA2), qui entraîne la libération d'acide arachidonique à partir des phospholipides membranaires. En utilisant un modèle d'injection intra cérébro ventriculaire unique d'une faible quantité de peptide Ab, nous avons pu observer que l'inactivation constitutive du gène de la cPLA2 protége les souris KO contre les perturbations mnésiques et empêche la réduction de l'expression de protéines synaptiques au sein de l'hippocampe, ces deux effets délétères étant constatés chez les animaux wild-type. Par la suite, nous avons montré que l'activation des sphingomyélinases, consécutive à l'exposition aux oligomères Ab, est indétectable dans des neurones en culture issus de souris KO. Dans ces mêmes neurones KO, nous avons constaté que la phosphorylation de Akt/PKB n'est pas altérée suite à l'exposition des cellules aux oligomères Ab. Enfin, nous avons pu mettre en évidence une diminution de l'expression de la protéine précurseur du peptide Ab (protéine APP), tant au niveau d'homogénats hippocampiques que de neurones en cultures, issus de souris KO. Néanmoins, des travaux supplémentaires sont requis pour établir le lien exact entre cette réduction de l'expression d'APP et la résistance aux oligomères Ab, tant in vitro qu'in vivo. Toutefois, ces résultats soulignent l'implication de la cPLA2 dans la neuro dégénérescence entrainée par les oligomères Ab, et font apparaitre cette enzyme comme une cible thérapeutique potentielle pour le traitement de la maladie d'AlzheimerSoluble beta-amyloid (Ab) oligomers putatively play a critical role in the early synapse loss and cognitive impairment observed in Alzheimer's disease. We previously demonstrated that A-beta oligomers activate cytosolic phospholipase A2 (cPLA2) which specifically releases arachidonic acid from membrane phospholipids. By using a single Ab oligomers intra cerebro ventricular injection, we observed that cPLA2 gene suppression prevents both the alterations of cognitive abilities and the reduction of hippocampal synaptic markers levels which are observed in wild type mice. We further demonstrated that the Ab oligomers-induced sphingomyelinase activation is suppressed and that the phosphorylation of Akt/PKB is preserved in neuronal cells isolated from KO mice. Interestingly, expression of the Ab precursor protein (APP) is reduced in hippocampus homogenates and neuronal cells from KO mice, but the relationship with the resistance of these mice to the Ab oligomers toxicity requires further investigation. These results therefore show that cPLA2 plays a key role in the Ab oligomers-associated neurodegenerative effects, and as such represents a potential therapeutic target for the treatment of Alzheimer's diseaseMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Clinical impact of digital and conventional PET control databases for semi-quantitative analysis of brain 18F-FDG digital PET scans

International audienceAbstract Purpose Digital PET cameras markedly improve sensitivity and spatial resolution of brain 18 F-FDG PET images compared to conventional cameras. Our study aimed to assess whether specific control databases are required to improve the diagnostic performance of these recent advances. Methods We retrospectively selected two groups of subjects, twenty-seven Alzheimer's Disease (AD) patients and twenty-two healthy control (HC) subjects. All subjects underwent a brain 18 F-FDG PET on a digital camera (Vereos, Philips®). These two group (AD and HC) are compared, using a Semi-Quantitative Analysis (SQA), to two age and sex matched controls acquired with a digital PET/CT (Vereos, Philips®) or a conventional PET/CT (Biograph 6, Siemens®) camera, at group and individual levels. Moreover, individual visual interpretation of SPM T-maps was provided for the positive diagnosis of AD by 3 experienced raters. Results At group level, SQA using digital controls detected more marked hypometabolic areas in AD (+ 116 cm 3 at p < 0.001 uncorrected for the voxel, corrected for the cluster) than SQA using conventional controls. At the individual level, the accuracy of SQA for discriminating AD using digital controls was higher than SQA using conventional controls (86% vs. 80%, p < 0.01, at p < 0.005 uncorrected for the voxel, corrected for the cluster), with higher sensitivity (89% vs. 78%) and similar specificity (82% vs. 82%). These results were confirmed by visual analysis (accuracies of 84% and 82% for digital and conventional controls respectively, p = 0.01). Conclusion There is an urgent need to establish specific digital PET control databases for SQA of brain 18 F-FDG PET images as such databases improve the accuracy of AD diagnosis

No prognostic value of routine cerebrospinal fluid biomarkers in a population-based cohort of 407 multiple sclerosis patients

International audienceBackground: We aimed to determine the association of clinical and routine cerebrospinal fluid biochemical markers (total protein, IgG index and oligoclonal bands) with disability in multiple sclerosis and whether these biomarkers assessed at diagnosis add prognostic value. Methods: We followed a cohort of patients included in the Multiple Sclerosis Lorraine Register (eastern France) who had a diagnosis of multiple sclerosis for at least 5 years, as well as biological markers values and MRI findings (Barkhof's criteria). In a Cox regression model, endpoint was time to score of 4 on the Expanded Disability Status Scale (EDSS) (i.e., limited time walking without aid or rest for more than 500 m). Results: For 407 patients included, the median time from multiple sclerosis onset to EDSS score 4 was 4.5 years [2.2-7.2]. Cerebrospinal fluid total protein factor < 500 mg/L was associated with EDSS score 4 on bivariate analysis (hazard ratio 0.66, 95% confidence interval 0.46-0.95, p = 0.02). On multivariate analysis, older age at disease onset (= 50 years) and initial primary progressive course of MS but not biological markers predicted worse prognosis. Conclusion: Routine cerebrospinal fluid biological markers at diagnosis were not prognostic factors of multiple sclerosis progression

Age-related changes in regiospecific expression of Lipolysis Stimulated Receptor (LSR) in mice brain

International audienceThe regulation of cholesterol, an essential brain lipid, ensures proper neuronal development and function, as demonstrated by links between perturbations of cholesterol metabolism and neurodegenerative diseases, including Alzheimer's disease. The central nervous system (CNS) acquires cholesterol via de novo synthesis, where glial cells provide cholesterol to neurons. Both lipoproteins and lipoprotein receptors are key elements in this intercellular transport, where the latter recognize, bind and endocytose cholesterol containing glia-produced lipoproteins. CNS lipoprotein receptors are like those in the periphery, among which include the ApoB, E binding lipolysis stimulated lipoprotein receptor (LSR). LSR is a multi-meric protein complex that has multiple isoforms including α and α', which are seen as a dou-blet at 68 kDa, and β at 56 kDa. While complete inactivation of murine lsr gene is embryonic lethal, studies on lsr +/-mice revealed altered brain cholesterol distribution and cognitive functions. In the present study, LSR profiling in different CNS regions revealed regiospecific expression of LSR at both RNA and protein levels. At the RNA level, the hippocampus, hypo-thalamus, cerebellum, and olfactory bulb, all showed high levels of total lsr compared to whole brain tissues, whereas at the protein level, only the hypothalamus, olfactory bulb, and retina showed the highest levels of total LSR. Interestingly, major regional changes in LSR expression were observed in aged mice which suggests changes in cholesterol homeostasis in specific structures in the aging brain. Immunocytostaining of primary cultures of mature murine neurons and glial cells isolated from different CNS regions showed that LSR is expressed in both neurons and glial cells. However, lsr RNA expression in the cerebellum was predominantly higher in glial cells, which was confirmed by the immunocytostaining profile of cerebellar neurons and glia. Based on this observation, we would propose that LSR in glial cells may play a key role in glia-neuron cross talk, particularly in the feedback control of cholesterol synthesis to avoid cholesterol overload in neurons and to maintain proper functioning of the brain throughout life

Additional Use of A beta(42)/A beta(40) Ratio with Cerebrospinal Fluid Biomarkers P-Tau and A beta(42) Increases the Level of Evidence of Alzheimer's Disease Pathophysiological Process in Routine Practice

International audienceBackground: Cerebrospinal fluid (CSF) biomarkers have recently been included in the criteria for the diagnosis of Alzheimer's disease (AD). Since interpretation of CSF profile requires the combination of three parameters, biological data are not always conclusive and isolated elevation of phosphorylated tau (P-tau) or reduction of amyloid-beta (A beta)(42) alone can be observed. In these cases, A beta(42)/A beta(40) ratio could be more relevant than A beta(42) absolute values by considering inter-individual variations in the total amyloid load. Objective: The objective of this study was to assess the use of A beta(42)/A beta(40) ratio to improve the accuracy of biological conclusions in the diagnosis of patients with ambiguous CSF A beta(42) or tau results. Methods: Among 386 lumbar punctures analyzed in the lab in 2 years, 122 showed ambiguous biological data that were completed by CSF A beta(40) quantification and A beta(42)/A beta(40) ratio calculation. A biological conclusion was then made using 0.05 as the A beta(42)/A beta(40) ratio cut-off. Results: Our results showed that one-third of the biological profiles of patients with atypical dementia were ambiguous. The addition of A beta(42)/A beta(40) ratio increased the proportion of interpretable biological profiles from 69% to 87%, without changing the conclusion when usual biomarkers (A beta(42) and P-tau) were concordant. Conclusion: Our results support the use of the A beta(42)/A beta(40) ratio in addition to the usual CSF AD biomarkers for patients with ambiguous biological profiles. This method could be specifically directed to this population in order to improve the level of certainty for clinical routine practice

Transfer Phenomena of Nanoliposomes by Live Imaging of Primary Cultures of Cortical Neurons

Soft nanoparticles, and in particular, nanoliposomes (NL), have attracted increasing interest for their use in food, nutraceuticals, and in particular, in pharmaceutics for drug delivery. Recent data using salmon lecithin NL suggest that these NL, rich in omega-3 (n-3) fatty acids, can improve the bioavailability and transport of molecules through the blood brain barrier (BBB) to target the brain for the prevention and treatment of neurodegenerative diseases. The objective of this study was to characterize the physicochemical properties and analyze the transfer phenomena of salmon lecithin NL over time in neurons to better understand the behavior of NL in an intracellular environment. To test this, primary cultures of cortical neurons from rat embryos were incubated with salmon lecithin NL from day 3 after cell culture, for up to 104 h. The physicochemical properties of NL such as size, speed, morphology and the diffusion coefficient in the live cultures, were studied over time. Image analysis of cell morphology showed dendritic growth and neuronal arborization after 48 h of exposure to NL, for up to 104 h. Results showed an NL stability in size, speed and diffusion coefficient over time, with a peak at 48 h, and then a return to baseline value at the end of incubation. The average speed and diffusion coefficient achieved provided important information on the mode of entry of NL into neurons, and on the slow diffusion rate of NL into the cells. Analysis of videos from 2 h to 104 h showed that significant levels of NL were already internalized by neurons after 3 h incubation. NL appearance and intracellular distribution indicated that they were packed in intracellular compartments similar to endocytic vesicles, suggesting internalization by an active endocytic-like process. The results obtained here demonstrate internalization of NL by cortical neurons by an active endocytic-like process, and suggest the potential use of NL for time-release of therapeutics aimed towards prevention or treatment of neurodegenerative diseases

Expression profile of hepatic genes related to lipid homeostasis in LSR heterozygous mice contributes to their increased response to high-fat diet

Perturbations of lipid homeostasis manifest as dyslipidemias and obesity, which are significant risk factors for atherosclerosis and diabetes.Lipoprotein receptors in the liver are key players in the regulation of lipid homeostasis, among which the hepatic lipolysis stimulated lipoprotein receptor, LSR, was recently shown to play an important role in the removal of lipoproteins from the circulation during the postprandial phase. Since heterozygous LSR+/- mice demonstrate moderate dyslipidemia and develop higher body weight gain in response to high-fat diet compared with littermate LSR+/+ controls, we questioned if LSR heterozygosity could affect genes related to hepatic lipid metabolism.A target-specific qPCR array for 84 genes related to lipid metabolism was performed on mRNA isolated from livers of 6 mo old female LSR+/- mice and LSR+/+ littermates following a 6 wk period on a standard (STD) or high-fat diet (60% kcal, HFD). Of the 84 genes studied, 32 were significantly downregulated in STD-LSR+/- mice compared with STD-LSR+/+, a majority of which were PPARα target genes involved in lipid metabolism and transport, and insulin and adipokine-signaling pathways. Of these 32 genes, 80% were also modified in HFD-LSR+/+, suggesting that STD-LSR+/- mice demonstrated a predisposition towards a "high-fat"-like profile, which could reflect dysregulation of liver lipid homeostasis.Since similar profiles of genes were affected by either LSR heterozygosity or by high-fat diet, this would suggest that LSR is a key receptor in regulating hepatic lipid homeostasis, and whose downregulation combined with a Western-type diet may increase predisposition to diet-induced obesity