Le vieillissement des populations est corrélé à l’augmentation des pathologies neurodégénératives liées à l’âge, plus particulièrement la maladie d’Alzheimer. La recherche de marqueurs précoces de la maladie ainsi que l’élaboration de nouvelles stratégies thérapeutiques constituent un enjeu de taille. Parmi les mécanismes moléculaires de la formation des plaques amyloïdes actuellement explorés, les formes oligomériques tronquées de peptide amyloïde (Aß), notamment le peptide Aß3(?pE)??42? retrouvé à des stades précoces de la maladie, joueraient un rôle déterminant. Ces travaux de thèse ont permis de montrer, dans un premier temps, que l’injection intracérébrale de ce peptide chez la souris entraîne des altérations de la mémoire de travail et des capacités d’apprentissage, associées à une accumulation d’espèces réactives dérivées de l’oxygène dans des régions cérébrales spécifiques (hippocampe et bulbes olfactifs) de ces animaux. Des essais menés in vitro sur des cultures primaires de neurones de souris montrent leur implication dans les voies apoptotiques impliquant l’activation des caspases et la cascade métabolique de l’acide arachidonique. La seconde étape de ces travaux a constitué en l’étude des effets protecteurs d’un peptide antiapoptotique d’origine endogène, l’humanine (HN) et son variant S14G (HNG). In vitro, un effet protecteur de ces peptides a été mesuré après traitement de neurones en culture par le peptide A[bêta]3?(pE)42.??? Les résultats les plus marquants résident dans les observations faites in vivo : en effet, ces peptides inhibent l’effet délétère de l’injection intracérébroventriculaire du peptide Aß3?(pE??)42?? en restaurant les performances mnésiques des animaux dans les tests comportementaux. A la lumière de ces résultats, les peptides HN pourraient constituer de nouveaux outils thérapeutiques dans le traitement ou la prévention des dommages cellulaires précoces liés à la présence des oligomères solubles du peptide Aß / Aging of population is correlated to the increase of neurodegenerative disease, more particularly Alzheimer disease. Defining early diagnostic markers and new therapeutic strategies are highly relevant. Among the molecular pathways which are currently developed, N-terminal-truncated forms of amyloid-ß (Aß) peptide have been recently suggested to play a pivotal role in the disease. Among them, Aß3(?pE)42 ?peptide is the dominant Aß species in amyloid plaques. We first investigated the effects of soluble oligomeric Aß3(pE) 42 after intracerebroventricular injection on mice learning capacities and the molecular mechanisms of in vitro neurotoxicity. Mice injected with soluble Aß3(pE) 42 displayed impaired spatial working memory and delayed memory acquisition. These cognitive alterations were associated with free radical overproduction in hippocampus and olfactory bulbs. In vitro, Aß3(pE) 42 oligomers induced a redox-sensitive neuronal apoptosis involving caspase activation and an arachidonic acid-dependent pathway. The second goal of this work was to investigate the protective effects of the apoptosis rescue endogenous peptide humanin (HN) and its S14G mutant (HNG). In vitro, we measured their inhibitory effect on neuronal death and apoptotic events resulting from soluble Ab oligomer treatment. What’s of particular interest is the in vivo restoration of soluble Aß3(pE) 42 oligomer-induced mnesic impairment. Thus, HN peptides might serve as new drug candidates for treatment or prevention of early cellular damages linked to soluble A[bêta] oligomers

The present paper analyses the neuroanatomical and neuropsychological backgrounds of art reception and art creation in modern visual art and creative processes. It critically presents two models of aesthetic experience to provide a comprehensive theoretical basis for the discussion. The research purpose is to show that with increasing experience and expertise the referential frame of the aesthetic judgment is changing and that neural processes involved in object recognition provide a starting point for visual aesthetics. Thus, the investigation focuses on constructing and testing neuropsychological theories that fall in the domain called 'neuroaesthetics'. These theories, in turn, serve as a starting point to formulate neural laws of art and aesthetics and aesthetic experience. Some artistic styles, such as expressionism, reflect specific neural processes. Various studies indicate correlations between hemispheric specialisation and art or creativity and show the right hemisphere plays a particular role in it. However, studies exploring the neural correlates of aesthetic preference have yielded mixed results. Furthermore, neuroimaging studies have proved that different categories of modern artworks are processed in different areas of the brain. These diverging results will be discussed in a critical assessment of the two models of aesthetic experience. Besides, the question of identifying exclusive neural correlates of aesthetic preference will be raised. Comparing amateurs and experts has revealed the more reduced the cortical activation, the more efficiently it works. Biological and neuropsychological factors of creativity point out the meaning of the activation level, cognitive inhibition and prefrontal cortex. Divergent thinking differs from convergent thinking in terms of the neural level. Neurodegenerative processes and brain injuries sometimes influence the artistic output surprisingly or even launch it. Lesion studies contributing to understanding art experience will be explained. / Psychology / M.A. (Psychology)

Cette thèse de sociologie porte sur les pratiques de sommeil des couples vieillissants confrontés à une maladie neurodégénérative. Elle se fixe comme objectif de saisir les dynamiques temporelles et spatiales de ces pratiques de sommeil, centrales dans la vie du couple, au fil de l'évolution de la maladie en accordant une attention particulière aux relations de genre. Nous avons interviewé 30 couples à domicile, dont 12 concernés par la maladie à corps de Lewy et 18 par la maladie d'Alzheimer et nous avons intégré des dispositifs d'enquête tels que la rédaction de journaux de sommeil, de journaux audio et la constitution d'un ensemble de documentation photographique. L'analyse se déploie selon trois axes. Le premier axe consiste à analyser le rôle du veilleur de nuit assumé par le conjoint aidant. Nous avons constaté le passage du statut de conjoint dormant à celui de "conjoint veilleur". Le rôle de conjoint veilleur est caractérisé par la production d'un travail domestique de soin qui se déroule la nuit et que nous avons appelé "travail domestique nocturne de soin". Nos résultats montrent que ce travail domestique nocturne peut amener le conjoint veilleur à un état d'épuisement qui peut pousser au choix d'institutionnaliser son conjoint malade. Ce travail domestique s'articule avec un état d'inquiétude nocturne du conjoint veilleur qui engendre un sommeil spécifique que l'on peut qualifier de "sommeil en état d'alerte". Il est aussi doublement invisible : il est constitué par des activités se déroulant la nuit et il repose souvent sur les femmes. Le deuxième axe consiste à analyser l'impact de la maladie et des troubles cognitifs sur l'organisation des espaces liés au sommeil en mettant en lumière les négociations qui se font autour de la chambre conjugale. Nous avons dégagé les raisons pour lesquelles une partie des conjoints reste attachée au fait de dormir ensemble. Nous avons aussi analysé les dimensions corporelles liées au partage du lit, contexte où la relation entre les corps trouve son expression privilégiée. Nous avons exploré les expériences de distanciation des conjoints : les significations et les pratiques autour du choix de dormir en couple mais séparés, de faire chambre à part. Le dernier axe porte sur l'analyse des stratégies hétérogènes de la gestion du sommeil telles que l'utilisation des médicaments pour dormir, le recours à la garde nocturne en institution ou au domicile et, enfin, le sommeil diurne. Nous avons analysé les raisons de l'adhésion ou du refus de la part des conjoints aidants et nous avons constaté que la vulnérabilité qui caractérise la nuit et le sommeil peut rendre difficile le recours aux stratégies de gestion du sommeil. / This doctoral dissertation in sociology examines the sleep practices of ageing couples confronted with neuro-degenerative conditions. It aims to understand the time- and space-related aspects of these sleep practices, so central to couples’ lives, throughout the different stages of illness, and places particular emphasis on gender-based relations. Thirty couples were interviewed in their homes, 12 of whom were affected by Lewy Body Dementia and 18 by Alzheimer’s Disease. Empirical methods such as sleep journals, audio journals, and photographic documentation were incorporated into the study’s methodology. The study is divided into three branches. The first branch examines the role of “night-time guardian” assumed by the caregiving partner. The author was able to observe that a shift takes place from the status of sleeping partner to that of night-time caregiver. The role of the “night-time guardian” is characterized by domestic labor that takes the form of caregiving provided at night, a phenomenon the author calls “nocturnal domestic caregiving work”. The findings of the study show that this domestic night-time work can bring about a state of exhaustion in caregiving partners that can drive them to institutionalize the partner suffering from a medical condition. In addition to this domestic work, caregiving partners are prone to a state of night-time worry that results in a specific variety of sleep that can be described as “alert sleep”. This domestic work also goes largely unseen for two reasons: it is made up of activities that take place at night, and it often falls to women. The study's second branch offers an analysis of the impact of illness and cognitive disorders on the way areas of the home associated with sleep are organized, bringing to light the give-and-take that occurs where the marital bedroom is concerned. The author examined the reasons some sleep partners continue to insist on sleeping together. Also addressed are the bodily aspects of shared beds, a special context in which the bonds shared between bodies can be expressed in a unique way. The dissertation further explores the experience of placing distance between sleep partners: the meanings and practices surrounding the decision to sleep as a couple but in separate rooms. The final branch of the study examines a range of strategies used to manage sleep, such as taking sleeping medication, turning to in-home or institutional night-time caretaking, and day-time sleep. The author surveyed the reasons that caregiving partners accepted or refused to utilize these strategies, and the study’s findings show that the vulnerability represented by night and sleep can render it difficult to decide to use strategies to manage sleep.

As septinas fazem parte de uma família de proteínas de ligação ao nucleotídeo guanina. As septinas têm mostrado ter um papel importante na citocinese e outros processos celulares, incluindo a determinação da polaridade celular e reorganização do citoesqueleto. Todos os membros da família de septinas são compostos por três domínios: um N-terminal variável, um domínio central GTPase e uma região C-terminal que inclui sequências de coiled-coil. Septinas possuem uma característica de polimerizarem para formar complexos hetero-oligoméricos altamente organizados, in vivo e in vitro. Estruturas homo-oligoméricas também foram observadas, embora sua função ainda não esteja bem estabelecida. A Septina 2 humana (SEPT2) se acumula no sulco de clivagem de células em divisão, desde a anáfase até a telófase, além de interagir com a actina, e também está envolvida em doenças neurodegenerativas, como mal de Azheimer. Nesse estudo, a ORF que codifica SEPT2, bem como os fragmentos que codificam seus domínios, foram clonados, expressos em E.coli e purificados por cromatografia de afinidade e cromatografia de exclusão molecular. Os produtos foram analisados por espectroscopia de dicroísmo circular, espalhamento de luz a ângulo fixo e espectroscopia de fluorescência extrínseca, usando Tioflavina-T, que é um marcador clássico para fibras amilóides. Em todos os casos, os produtos formaram homodímeros in vitro, e também agregaram em temperaturas fisiológicas. O desenovelamento térmico das proteínas recombinantes revelou a presença de uma população intermediária de desenovelamento, rica em folhas-β, e que ligam Tioflavina-T, sugerindo uma estrutura amiloidogênica para essa proteína, confirmada pelos programas de predição TANGO e WALTZ. Imagens dessas fibras foram obtidas usando Microscopia eletrônica de Transmissão, evidenciando uma agregação organizada das proteínas. Além disso, usando monocamadas de Langmuir, foi possível confirmar a ligação específica de SEPT2 ao fosfolipídeo fosfatidilinositol 4,5-bifosfato (PtdIns(4,5)P2). Essa ligação específica mantém a estrutura secundária de SEPT2, observada pela técnica PM-IRRAS, algo que não ocorre caso o lipídio seja inespecífico, sugerindo uma associação de SEPT2 com a membrana plasmática e podendo ter um papel na regulação das septinas. Por meio da técnica de duplo híbrido em levedura, identificamos proteínas que interagem com a SEPT2, como a MPBI e a DCTN2, auxiliando na elucidação de processos em que a SEPT2 possa participar. O conjunto dos resultados sobre a estabilidade, os processos de agregação de SEPT2 e a identificação de novos parceiros protéicos de interação, obtidos nesse trabalho, contribuíram para o melhor entendimento da função da SEPT2 e de seu envolvimento em desordens neurodegerenativas. / Septins are members of a conserved group of GTP-binding and filament-forming proteins. They are involved in a variety of cellular processes, such as microtubule regulation, vesicle trafficking, the formation of scaffolding platforms and actin dynamics. Human Septin 2 (SEPT2) has an N-terminal polybasic region responsible for lipid binding, a GTPase domain, and a C-terminal domain. SEPT2 is essential for cytokinesis and it is found in many tissues, mainly in the brain. Together with SEPT1 and SEPT4, it is accumulated in deposits known as neurofibrillary tangles in Alzheimers disease, which is evidence that SEPT2 may be involved in this process. In this study, the human SEPT2, and its domains, were cloned, expressed in E.coli and purified by affinity and size-exclusion chromatographies. The proteins form homodimers in vitro, suggesting that the GTPase domain is enough to promote the oligomerization. Thermal unfolding revealed the formation of aggregates under physiological conditions, which have the ability to bind a specific amyloid dye, Thioflavin-T, suggesting them to be an amyloidal fiber. Besides, in silico prediction programs, TANGO and WALTZ, corroborate that SEPT2 contain regions with high probability of aggregation and amyloidogenic formation, respectively. Moreover, we observed 20-50 nm thick filamentous structures by electron microscopy of negatively stained. Using Langmuir monolayers at the cell membrane lipid packing, SEPT2 and SEPT2NG bound to the phospholipid phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). Results from in situ PM-IRRAS experiments indicated that the secondary structure of SEPT2 is preserved upon interacting with PtdIns(4,5)P2, but not when interacting with DPPC - which is not specific for SEPT2 - at the air/water interface suggesting an association with the plasma membrane and a role in septin regulation. Furthermore, we also identified protein partners of SEPT2, from both human leukocyte and brain fetal cDNA libraries, using the yeast two-hybrid system. SEPT2 was shown to interact with: septins 6 and 4; a serine-protease and a MAP inhibitory protein; an ubiquitin-conjugating enzyme; and proteins related to cellular division. Thus, taken together this study contributed for the knowledgment of the stability and the aggregation kinetic of the SEPT2, leading to a better understanding of this protein and their role in neurodegenerative disorders.

Introducão: o comprometimento cognitivo leve (CCL) é reconhecido como um estágio transicional sintomático entre o envelhecimento normal e a demência, particularmente a doença de Alzheimer (DA). Apresenta como subtipos principais o amnéstico (CCLa), com comprometimento de memória, e o não amnéstico (CCLna), que apresenta perda de outras funções, principalmente executivas, de atenção, de linguagem e visuoespaciais. Aparentemente o CCLna tem menor taxa de conversão para demências ao longo do tempo que o subtipo amnéstico, particularmente para a DA. Dessa forma, o CCLna poderia apresentar um perfil de biomarcadores diferente do CCLa no momento do diagnóstico. Estudos na literatura investigando o padrão de biomarcadores no CCLna como grupo independente são raros, alguns destes indicando perfil menos relacionado à DA no CCLna que o visto no CCLa. Segundo nosso conhecimento, não há estudos investigando concomitantemente volume e metabolismo cerebrais, além de biomarcadores no LCR de uma mesma amostra de CCLna, em comparação com CCLa e um grupo de idosos cognitivamente normais. Objetivo: investigar as alterações de volume e metabolismo cerebral em grupos de indivíduos com os subtipos amnéstico e não amnésico de CCL, comparativamente a voluntários idosos sem comprometimento cognitivo, com o intuito de avaliar se há concordância entre estas alterações. Avaliou-se ainda possíveis associações entre os perfis dos estudos de imagem com padrões classicamente descritos na para CCL em risco de evolução para DA, investigando ainda a existência de correlações entre destes achados com o dos diferentes biomarcadores no LCR e com dados clínicos. Métodos: cento e quatorze voluntários foram incluídos em três diferentes grupos: gCCLna (N = 38), gCCLa (N = 46) e GC (N = 30). Após entrevista clínica, exame neurológico e classificação por uma bateria de testes neuropsicológicos, estes foram submetidos a exames de RM cerebral (para excluir outras causas de comprometimento cognitivo e para análise de morfometria baseada em voxels - VBM) e de PET-18FDG cerebral. Analisou-se ainda os valores de biomarcadores no LCR (A?, tau e p-tau) de uma subamostra de pacientes (CCLna = 33, CCLa = 38). Resultados: os três grupos não apresentaram diferenças em relação às variáveis idade, escolaridade, sexo, fatores de risco cardiovascular (exceto por maior prevalência de dislipidemia no gCCLa) e hiperintensidades de substância branca na RM. Menores valores de mini-exame do estado mental foram observado nos grupos CCLa e CCLna em relação ao GC. O subgrupo amnéstico apresentou redução de volume em porções mediais e polares de ambos os lobos temporais em comparação com GC e gCCLna, além de áreas de redução do metabolismo no giro do cíngulo posterior e pré-cúneo direitos e giro temporal médio esquerdo em relação ao GC. Esse padrão de redução volumétrica e metabólica não foi visto no gCCLna, que demonstrou discreta redução volumétrica nos giros temporal inferior esquerdo e frontal médio direito em comparação com o GC. Nenhuma alteração metabólica persistiu no subgrupo não amnéstico após correção para efeito de volume parcial em comparação com o GC, havendo redução metabólica bilateral no giro frontal médio em comparação com o gCCLa. Não houve diferenças significativas nos biomarcadores de LCR entre os grupos CCLa e CCLna. Houve, porém, tendência de menores valores de peptídeo A? no gCCLa. Observou-se correlação positiva entre metabolismo no giro temporal médio esquerdo e rendimento em testes de memória; correlação negativa também foi observada entre os valores de A? e os de tau e p-tau no LCR. Conclusão: os grupos CCLa e CCLna apresentaram alterações de volume e metabolismo diferentes em comparação com o grupo controle, e estas alterações não apresentaram concordância entre si. Também não foram encontradas correlações entre os diferentes biomarcadores de imagem e no LCR, notando-se apenas correlação positiva entre metabolismo temporal e desempenho em testes de memória. O gCCLa apresentou padrões de metabolismo e volume cerebrais classicamente relacionados a risco de evolução para DA. Por outro lado, o grupo CCLna apresentou um padrão diferente de alterações metabólicas e volumétricas, com áreas menores de redução de volume e padrão mais heterogêneo de alterações metabólicas em relação ao grupo controle. O conjunto de achados de biomarcadores no gCCLna não é indicativo de nenhum perfil específico de evolução para demências / Introduction: Mild cognitive impairment (MCI) is presumably a transitional stage between normal aging and dementia, particularly Alzheimer\'s disease (AD). Non-amnestic subtypes (naMCI) present with executive, attention, visuospatial and language dysfunctions. They have a lower conversion rate to dementia compared to amnestic subtypes (aMCI). Investigations regarding biomarker profiles of naMCI as an independent group are scarce. To our knowledge there is no study investigating the brain volumetric and metabolic features, as well as the profile of cerebrospinal fluid (CSF) biomarkers of naMCI patients as a single group in comparison to aMCI and cognitively normal elderly patients (control group - CG). Objective: to investigate the brain volumetric and metabolic changes in individuals presenting amnestic and non-amnestic MCI subtypes in comparison to elderly volunteers without cognitive impairment, aiming to verify if there are agreements between these changes. Possible associations between the imaging profile of these groups and classical patterns of high risk for developing AD were also evaluated, as well as possible correlations between imaging biomarkers, CSF biomarkers and clinical data. Methods: a hundred and fourteen (114) patients were included in three different groups: naMCIg (N = 38), aMCIg (N = 46) and CG (N = 30). Patients underwent brain MRI (in order to exclude other causes of the cognitive impairment but also for VBM analysis) and [18F]FDG-PET. A subsample (naMCIg = 33, aMCIg = 38) also underwent a lumbar puncture in order to assess the profile of amyloid-ß peptide, tau and phosphorylated tau protein levels in the CSF. Results: There was no difference in CSF biomarkers, education years, age, gender and cardiovascular risk factors between the naMCI and aMCI groups, except for a higher prevalence of dyslipidemia in aMCI. The amnestic MCI group had lower rBGM in relation to control group in the precuneus, posterior cingulate and left medium temporal gyrus. Compared to aMCIg, naMCIg presented with bilateral prefrontal cortex hypometabolism, but without metabolic changes in relation to CG after correction for partial volume effect. Amnestic MCI group had bilateral temporal lobe volume reduction in comparison to naMCI and CG, particularly in the polar and mesial parts of the temporal lobe. Non-amnestic MCI presented with discrete volumetric reductions in comparison to CG, Conclusion: Volumetric and metabolic alterations were different and essentially discordant between aMCI and naMCI groups in comparison to CG. Amnestic MCI showed metabolic and volumetric profiles classically related to MCI due to AD, while naMCI group presented with less-significant areas of volumetric and metabolic reductions in relation to control group. Our non-amnestic MCI group probably represents a heterogeneous group with a different pattern of neurodegeneration than the classical MCI due to AD

No description available.

Hong, Sijia. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 197-234). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

No description available.

De nombreux tests de dépistage des troubles cognitifs légers ont été élaborés ces dernières années afin d'identifier des personnes plus à risque de développer une maladie neurodégénérative telle que la maladie d'Alzheimer. Plusieurs indices (sensibilité, spécificité, valeurs de prédiction et rapports de vraisemblance) permettent d'évaluer la performance et l'utilité d'un test en pratique. L'objectif de cette thèse était d'évaluer le degré de variation de la performance d'un outil de dépistage des troubles cognitifs légers et ses conséquences sur la prise de décision clinique. Nos résultats montrent une variation importante de la performance de l'outil étudié en fonction des caractéristiques démographiques des individus, de la nature et la sévérité du trouble cognitif La performance globale d'un test ne serait donc pas constante et exposerait à un risque de sous-estimer ou de surestimer la présence de troubles cognitifs dans certains sous-groupes de l'échantillon d'étude. La mesure de ce phénomène de variation (ou effet de spectre) devrait faire partie des étapes obligatoires de la validation d'un test de dépistage des troubles cognitifs. Elle implique l'analyse de grands échantillons permettant de rendre compte de la complexité de l'interprétation d'un test et son application au niveau pratique. L'utilisation de valeurs seuils ajustées selon l'âge et le niveau scolaire, est proposée afin d'améliorer la prise de décision clinique. Nous discutons également de l'intérêt d'utiliser le concept épidémiologique de dépistage dans la recherche et l'identification de troubles cognitifs et proposons le terme plus approprié de repérage qui ne préjuge pas de leur étiologie. / In recent years, numerous tests have been proposed to screen Mild Cognitive Impairment (MCI) in order to identify individuals who are at risk for developing a neurodegenerative pathology such as Alzheimer's disease. Severa! indices (sensitivity, specificity, predictive values and likelihood ratios) enable to assess the performance and the utility of a test in clinical practice. The main objective of this thesis was to determine the degree of variation of an MCI screening test performance and its impact on clinical decision. Our results showed that performance indices of the study test may vary depending on the demographic characteristics of the individuals, the type and the degree of cognitive impairment. They also highlight that the overall performance of a screening test is not fixed and may result in failure to identify cognitive impairment in true cases and misclassified non cases as cognitively impaired in some subgroups of the study sample. These findings support the perspective that this subgroup variation ( or spectrum effect) should routinely be taken into account to assess the quality of a cognitive screening test. One way to minimize the impact of this phenomena would be to focus the assessment on broad and well defined subgroups of patients. The use of adjusted eut-offs values could help clinicians to increase their level of certainty regarding whether a cognitive impairment is present. We also discuss the interest of using the epidemiological concept of screening in the identification of cognitive impairments and propose a more appropriate term of cognitive impairment detection without prejudging its aetiology

Garantir la qualité des produits sanguins est crucial. Les lysats plaquettaires (LP) riches en facteurs de croissance (FC) s’imposent comme le complément idéal pour l’expansion ex vivo des cellules souches, et comme produit thérapeutique pour la régénération cellulaire. L’intérêt est croissant pour les microparticules (MPs) extracellulaires, mais l’expression de phosphatidylsérine à leur surface peut induire des effets thrombotiques et inflammatoires. L’autre risque transfusionnel, la transmission de virus, dont le virus de l’hépatite C (VHC), est maîtrisable par traitements de réduction virale par solvant/détergent (S/D), chauffage, ou nanofiltration. Nous avons étudié des technologies de sécurisation des produits sanguins: (a) élimination des MPs par nanofiltration sur filtres de 75 nm et (b) traitements S/D, chauffage à 56°C ou nanofiltration pour inactiver ou éliminer le VHC. Les informations ont été utilisées pour développer des LP utiles en médecine régénérative. L’un d’eux destiné à la neurorégénération, a été préparé en émettant l’hypothèse qu’un lysat de culot plaquettaire (LCP) enrichi en facteurs neurotrophiques et dépourvu de protéines plasmatiques se montrerait efficace contre les maladies neurodégénératives. Nos résultats montrent que la nanofiltration sur des filtres de 75 nm préserve la composition en protéines plasmatiques, et le pouvoir hémostatique. La nanofiltration retire les MPs et évite, in vitro, la génération de thrombine. Par ailleurs le traitement S/D à 31°C pour 30 minutes élimine le pouvoir infectieux du VHC. Pris globalement les traitements de nanofiltration et S/D apparaissent donc comme des méthodes de choix pour l’amélioration de la sécurité du plasma vis à vis de risques thrombogènes et infectieux. Nous avons ensuite préparé un LCP appauvri en protéines plasmatiques (dont le fibrinogène) et enrichi en un mélange pléiotrope physiologique de FC destiné à l’administration cérébrale. Les analyses par ELISA et par protéomique ont montré qu’un chauffage de 56°C pour 30 min réduisait le contenu en protéines et modifiait favorablement la composition relative en facteurs neurotrophiques. Par ailleurs le chauffage améliore l’action neuroprotectrice et, associé aux traitements S/D et de nanofiltration, contribue à l’inactivation du VHC. Ce LCP exerce une neuroprotection élevée dans des modèles de la maladie de Parkinson (MP) tout à la fois (a) in vitro (cellules LUHMES différentiées en neurones dopaminergiques et exposées au MPP+) et (b) in vivo (souris intoxiquées par MPTP). L’expression de la tyrosine hydroxylase (TH) dans la Substantia nigra pars compacta montre que l’administration intracérébroventriculaire (ICV) ou intranasale (i.n.) apparait comme une option thérapeutique possible des maladies neuro-dégénératives. Les études cellulaires In vitro sur LUHMES et NSC34 ont montré que l’inhibition spécifique des voies signalétiques relayées par AkT et ERK altère l’activité neuroprotectrice du LC. Des événements neuro-inflammatoires pouvant aggraver l’évolution des maladies neurodégénératives, nous avons vérifié que le LCP n’induit pas de marqueurs inflammatoires (COX-2, iNOS) chez des cellules microgliales BV2, et pouvait même diminuer celle de COX-2 après exposition à des lipopolysaccharides. De plus, nous avons identifié que le LCP contenait 1.7 x 1012 MP/mL d’une taille moyenne de 160 nm. Isolées, ces MPs pourraient exercer un rôle neuroprotecteur des cellules LUHMES exposées à des agents neurotoxiques. En conclusion, nos résultats montrent la faisabilité technique à préparer des lysats plaquettaires viro-inactivés pour des usages dans le domaine de la médecine régénérative, y compris comme agent neuroprotecteur du système nerveux central. / Ensuring quality and safety of blood products is crucial. Platelet lysates (PL) rich in growth factors (GFs) have emerged as ideal clinical-grade supplement for ex vivo expansion of mesenchymal stromal cells, and as therapeutic product promote cellular regeneration. Interest for platelet extracellular microparticles (MPs) is growing but expression of phosphatidylserine on their surface may cause thrombotic and inflammatory side effects. Another transfusional risk, transmission of viruses, including hepatitis C virus (HCV), can be fully controlled by dedicated viral reduction methods as solvent/detergent (S/D) or heat treatments, or nanofiltration. We have evaluated technologies to secure therapeutic blood products: (a) removal of MPs by 75nm-nanofiltration and (b) inactivation/removal of HCV by S/D or 56°C heat treatments, or nanofiltration. Data have been used to develop LP of interest for regenerative medicine. In particular, one, targeting neuroregenerative applications, has been prepared based on the hypothesis that a platelet pellet lysate (PPL) enriched in multiple neurotrophic growth factors and depleted of plasma proteins could exert potent neuroprotective actions in neurodegenerative disease models. Our data show that 75 nm-plasma nanofiltration preserved plasma protein biochemical profile, and hemostatic power. Nanofiltration removes MPs and avoids in vitro the generation of thrombin. In addition, the S/D treatment at 31°C for 30 minutes fully inactivates HCV infectivity. Therefore, altogether, nanofiltration and S/D emerge as choice procedures to improve the safety of plasma for thrombogenic and infectious risks. We have then prepared a PPL depleted of plasma proteins (in particular fibrinogen), and rich in a physiological pleiotropic mixture of neurotrophins for brain administration. ELISA and proteomics studies revealed that the heat-treatment at 56°C for 30 min decreased the protein content and favorably modified the relative composition in neurotrophic factors. Heat-treatment improved the neuroprotective activity and, together with S/D and nanofiltration contributed to HCV inactivation. This PPL exerted strong neuroprotective effects in Parkinson’s disease (PD) models (a) in vitro, using LUHMES cells exposed to MPP+ neurotoxin, and (b) in vivo, in mice intoxicated by MPTP neurotoxin. Expression of tyrosine hydroxylase (TH) in the Substantia nigra pars compacta indicated that brain delivery by intracerebroventricular (ICV) or intranasal (i.n.) administration may be a therapeutic option for disease-modifying strategies of neurodegenerative diseases. In vitro studies in LUHMES and NSC34 cells showed that specific inhibition of signal transduction pathways through AkT and ERK influenced PPL neuroprotective function. Since neuro-inflammation detrimentally affects neurodegenerative disorders, we verified that the PPL did not stimulate the release of inflammatory markers (e.g. COX-2, iNOS) by BV2 microglial cells in culture, and could even restrict COX-2 expression when cells were exposed to LPS. In addition, the PPL was found to contain 1.7 x 1012 MP/mL with a mean size of 160 nm. These MPs may exert neuroprotective activity on LUHMES cells exposed to neurotoxins. Altogether, our data demonstrate the technical feasibility of developing virally-safe customized platelet lysate preparations with specific applications for cell therapy and regenerative medicine, in particular as neuroprotective agents of the central nervous system.