Functionalization and Characterization of Magnetic Nanoparticles for the Detection of Ferritin Accumulation in Alzheimer's Disease

Early diagnosis in Alzheimer's disease (AD), prior to the appearance of marked clinical symptoms, is critical to prevent irreversible neuronal damage and neural malfunction that lead to dementia and death. Therefore, there is an urgent need to generate new contrast agents which reveal by a noninvasive method the presence of some of the pathological signs of AD. In the present study, we demonstrate for the first time a new nanoconjugate composed of magnetic nanoparticles bound to an antiferritin antibody, which has been developed based on the existence of iron deposits and high levels of the ferritin protein present in areas with a high accumulation of amyloid plaques (particularly the subiculum in the hippocampal area) in the brain of a transgenic mouse model with five familial AD mutations. Both in vitro and after intravenous injection, functionalized magnetic nanoparticles were able to recognize and bind specifically to the ferritin protein accumulated in the subiculum area of the AD transgenic mice.Fil: Fernández Cabada, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Politécnica de Madrid; EspañaFil: Martínez Serrano, Alberto. Consejo Superior de Investigaciones Científicas; España. Universidad Autónoma de Madrid; EspañaFil: Cussó, Lorena. Instituto de Investigacion Sanitaria Gregorio Marañón; España. Universidad Carlos III de Madrid; España. Centro de Investigación Biomédica en Red de Salud Mental; EspañaFil: Desco, Manuel. Instituto de Investigacion Sanitaria Gregorio Marañón; España. Centro de Investigación Biomédica en Red de Salud Mental; España. Universidad Carlos III de Madrid; EspañaFil: Ramos Gómez, Milagros. Universidad Politécnica de Madrid; Españ

Nanoneuromedicines for degenerative, inflammatory, and infectious nervous system diseases

Interest in nanoneuromedicine has grown rapidly due to the immediate need for improved biomarkers and therapies for psychiatric, developmental, traumatic, inflammatory, infectious and degenerative nervous system disorders. These, in whole or in part, are a significant societal burden due to growth in numbers of affected people and in disease severity. Lost productivity of the patient and his or her caregiver, and the emotional and financial burden cannot be overstated. The need for improved health care, treatment and diagnostics is immediate. A means to such an end is nanotechnology. Indeed, recent developments of health-care enabling nanotechnologies and nanomedicines range from biomarker discovery including neuroimaging to therapeutic applications for degenerative, inflammatory and infectious disorders of the nervous system. This review focuses on the current and future potential of the field to positively affect clinical outcomes. From the Clinical Editor Many nervous system disorders remain unresolved clinical problems. In many cases, drug agents simply cannot cross the blood-brain barrier (BBB) into the nervous system. The advent of nanomedicines can enhance the delivery of biologically active molecules for targeted therapy and imaging. This review focused on the use of nanotechnology for degenerative, inflammatory, and infectious diseases in the nervous system

Development of a Multimodal MRI Study to Characterize Morpho-Functional Features in Rodent Models of Alzheimer's Disease

Alzheimer’s Disease (AD) is the most common form of dementia, recognized by the World Health Organization as a global public health priority. It is a complex pathology characterized by the accumulation of the Amyloid-β (Aβ) peptide as extracellular plaques and of the intracellullar neuro fibrillary tangles (NFT) alongside with different events, such as chronic neuroinflammation and astrogliosis. None of the existing biomarkers is simultaneously specific for the pathology and sensitive to its progression. Metabolic and functional alterations are the earliest events described in the AD pathological cascade but shared with other form of dementia, while specific structural alterations occurs in a later stage of the disease. The use of transgenic models could simplify the development of new imaging biomarkers that would enable early diagnosis and making new treatments more effective. The objective of this work was to develop a multi-modal panel of magnetic resonance imaging (MRI) techniques and automated analysis pipelines, characterized by a high translational impact, in order to investigate the metabolic, functional and structural alterations in the brains of AD transgenic models. Results obtained in the APP23 transgenic mouse show that chemical exchange saturation transfer (CEST) imaging can be used to detect alterations in the brain uptake of the glucose analogue 2-deoxy-d-glucose (2DG) with a better resolution than PET and without the need of radioactive tracers. Moreover, a longitudinal study highlighted that significant structural and metabolic alterations can be found only in a late stage of the pathology. Furthermore, an advanced pipeline for the analysis of the rodent brain functional connectivity has been developed. This thesis demonstrates that the advantage to the experimental design adopted is simplifying longitudinal studies of the same animal cohort. The translation of the analysis pipelines adopted in human studies enables more powerful results and reduces the number of animals involved in research

MRI and histologic studies on early markers of Alzheimer's disease

This thesis adresses a variety of early markers of Alzheimer's disease, using MRI, histology and MRS. MRS is found to be promising for early diagnosis of AD. However this study is done on mice and should be replicated on AD patients over time. Besides the early markers the thesis descibes a potential difference between male and female in the development of AD in the brain. LUMC / Geneeskund

Standardization of research methods employed in assessing the interaction metallic-based nanoparticles and the blood-brain barrier: present and future perspectives

peer-reviewedThe full text of this article will not be available until the embargo expires on the 18/01/2020.Treating diseases of the central nervous system (CNS) is complicated by the presence of the blood-brain barrier (BBB), a semipermeable boundary layer protecting the CNS from toxins and homeostatic disruptions. However, this layer also excludes almost 100% of therapeutics, impeding the treatment of CNS diseases. The advent of nanoparticles, in particular metallic-based nanoparticles, presents the potential to overcome this barrier and transport drugs into the CNS. Recent interest in metallic-based nanoparticles has generated an immense array of information pertaining to nanoparticles of different materials, sizes, morphologies, and surface properties. Nanoparticles with different physico-chemical properties lead to distinct nanoparticle-host interactions; yet, comprehensive characterization is often not completed. Similarly, in vivo testing has involved a mixed evaluation of parameters, including: BBB permeability, integrity, biodistribution, and toxicity. The methods applied to assess these parameters are inconsistent; this complicates the comparison of different nanoparticle-host system responses. A systematic review was conducted to investigate the methods by which metallic-based nanoparticles are characterized and assessed in vivo. The introduction of a standardized approach to nanoparticle characterization and in vivo testing is crucial if research is to transition to a clinical setting. The approach suggested, herein, is based on equipment and techniques that are accessible and informative to facilitate the routine incorporation of this standardized, informative approach into different research settings. Thorough characterization could lead to improved interpretation of in vivo responses, which could clarify nanoparticle properties that result in favorable in vivo outcomes whilst exposing nanoparticle-specific weaknesses. Only then will researchers successfully identify nanoparticles capable of delivering life-saving therapeutics across the blood-brain barrier

Molecular neuroimaging of Alzheimer's disease

Alzheimer__s disease (AD) is the predominant form of dementia in the aging population and its increasing incidence represents an important socio-economic and public health concern. The hallmarks of this disease, amyloid plaques and neurofibrillary tangles, are thought to develop early in the disease pathogenesis, up to decades before first clinical symptoms occur. However, these pathological hallmarks are still difficult to detect in vivo, and therefore a definitive diagnosis can only be made post-mortem. A clinical imaging technique or biomarker capable of visualizing and quantifying amyloid plaques and associated early changes thus may enable an earlier diagnosis, better understanding of the pathophysiology and eventually aid therapy development. The work presented in this thesis aimed to develop innovative diagnostic imaging techniques to detect the histological signatures of AD using emerging ultra-high field MRI technologies (Part I) and molecular imaging strategies (Part II).Internationale Stichting Alzheimer Onderzoek, to-BBB, Guerbet Nederland B.V., Philips Healthcare, ABN Amro and ChipSoft B.V.UBL - phd migration 201

Caracterização físico-quimica de complexos de iões lantanídeos conjugados com pib e a sua interação com agregados Aβ(1-40)

Dissertação de Mestrado em Química apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A doença de Alzheimer é uma das patologias mais recorrentes no idoso, caracterizada por neuro-degeneração progressiva, provocando perturbações cognitivas devastadoras. O diagnóstico só é possível num estado avançado da doença através da apresentação de um quadro sintomatológico característico da patologia, exceptuando a sua forma familiar, associada a mutações já identificadas e caracterizadas. O diagnóstico definitivo da doença de Alzheimer esporádica é apenas obtido post mortem, devido à necessidade de um corte histológico do cérebro para avaliar a presença de placas amilóides, e é daqui que nasce a necessidade de identificar estas placas amilóides durante a vida do doente. Assim, foi desenvolvida uma sonda que contém duas partes: 1) o reagente de Pittsburg B (PiB), que é um fenil-benzotiazol, com comprovada afinidade pelos agregados amilóides, e 2) um derivado de DOTA ou DO3A, para o ligando L4 e L5, respectivamente, que oferece estabilidade termodinâmica e é cineticamente inerte, para a coordenação de um metal específico consoante a modalidade imagiológica a que se destina. No presente trabalho, estudou-se a possibilidade dos ligandos L4 e L5, com a coordenação do Eu3+ e do Tb3+, poderem ser usados em Imagiologia Óptica e a coordenação do Gd3+ com o ligando L5 foi investigado para sua utilização como agente de contraste em Imagiologia de Ressonância Magnética (IRM). Os ligandos possuem na sua constituição um fenil-benzotiazol (PiB), um sistema π conjugado que absorve na zona UV/Vis. Foi realizada uma caracterização fotofísica e estudada a eficiência da transferência de energia nos complexos formados pelos ligandos L4 e L5, pelo chamado efeito antena, para povoar o estado excitado dos iões emissores Eu3+ e Tb3+, uma vez que a sua excitação directa é proibida por simetria (regra de Laporte). Verificou-se que a presença de um ião metálico emissor provoca supressão do estado excitado S1 e T1 do cromóforo fenil-benzotiazol, através da redução do rendimento quântico e tempo de vida de fluorescência, bem como a redução do tempo de vida do estado tripleto (T1). Foi realizado o estudo da fotoestabilidade dos ligandos, que é uma das características fundamentais para estas sondas serem usadas em Imagiologia Óptica, e mostrou-se que o ligando L4 é estável, porém o ligando L5 é fotodegradável. A determinação do rendimento quântico de luminescência fornece um dado directo da potencialidade destas sondas funcionarem em Imagiologia Óptica, tendo este estudo sido acompanhado pela determinação do número de hidratação dos complexos, que é uma fonte importante de desactivação do estado excitado do metal. Os valores obtidos do rendimento viii quântico de luminescência são relativamente baixos, mostrando que a distância entre o cromóforo e o centro metálico influencia a eficiência de transferência de energia, sendo importante reduzir ao máximo esta distância. O complexo GdL5 mostrou propriedades físico-químicas promissoras para o seu uso em IRM, tais como ter uma relaxividade elevada. Uma vez que o complexo tem caracter anfifílico, juntamente com a sua hidrofobicidade, visto pelo seu valor de log P de 0.65±0.028, estas propriedades levam-no a formar micelas a baixas concentrações (20±5 μM), que provoca o aumento do seu tempo de correlação rotacional (τr) e consequentemente aumento da relaxividade. A interacção do complexo GdL5 com agregados do péptido Aβ1-40 provoca um aumento da relaxividade a campo magnético intermédio, sendo útil em IRM, aumentando o contraste da imagem. A capacidade do complexo GdL5 interagir com a albumina de soro humano permite-lhe ter um maior tempo de vida no plasma sanguíneo, evitando a sua rápida excreção. O estudo in vitro da interacção do complexo GdL5 com o péptido Aβ1-40 demonstrou que o complexo tem uma afinidade moderada pelos agregados Aβ amilóides (KD= 19.5 ± 3.0 μM) e que interage com a forma monomérica do péptido, nomeadamente da zona hidrofílica com grande densidade de carga, entre os resíduos F4 e F20. No entanto, a afinidade do complexo GdL5 é maior para os agregados amilóides, sendo uma característica importante uma vez que se pretende usar o complexo para detectar os agregados do péptido e não a sua forma monomérica. A investigação do efeito do complexo GdL5 na agregação e na estrutura secundária do péptido Aβ1-40 por dicroísmo circular e microscopia de transmissão electrónica mostrou que o complexo tem um efeito promotor da formação de fibrilas com estrutura em folha β, indicando que o complexo GdL5 poderá ter um efeito tóxico in vivo, apesar destes estudos terem sido realizados a concentrações de péptido muito superiores ao que se verifica in vivo. Em suma, o estudo dos complexos formados pelos ligandos L4 e L5 dão boas indicações para serem usados em Imagiologia, apesar de algumas propriedades físico-químicas não serem as mais adequadas para esta finalidade, sobretudo in vivo, uma vez que se tem verificado dificuldade destes complexos atravessarem a barreira hemato-encefálica. Desta forma, este estudo contribui para um melhor entendimento do design racional deste tipo de complexos para detecção precoce da doença de Alzheimer, de modo a permitir no futuro a melhoria das suas propriedades físico-químicas

Lipido-garraiatzaile nanoegituratu berriak Ω-3 gantz-azido poliinsaturatuetan eta TAT peptidotan oinarritutakoak gaixotasun neurodegeneratiboak tratatzeko

340 p.Neurodegenerative diseases (NDs) are an accelerating global problem, but we still lack routes to develop effective therapeutics. In this quest, it is crucial to identify novel drug candidates or drug carriers, which cross the blood-brain barrier (BBB) and reach the brain tissue. In the present doctoral thesis, we have focused on nanostructured lipid carriers (NLCs) development for the targeted delivery of NTFs. The NLCs surface modification with chitosan (CS) and TAT effectively deliver glial derived neurotrophic factor (GDNF) NTF in Parkinson Disease (PD) animal model, restoring its motor activity and modulation of the reactive gliosis. Moreover, the chronic administration of ¿-3 fatty acids to PD animal model led to animals¿ dopaminergic system improvement, and modulate the present neuroinflammation and oxidative stress. As a following step, the tested functional lipids were used to NLC development, retaining their ability as neuroprotective and anti-inflammatory agents. Finally, the compose NLCs with ¿-3 functional lipids and surface modified with TAT and CS tested positive to pass across human BBB in vitro model, showing as a good candidate to target the brain. The anti-inflammatory and anti-oxidative potential of these ¿-3 nanocarriers successfully counteracted the inflammatory state present in human microglia cell line. The co administration with glial derived neurotrophic factor (GDNF) triggered the endogenous anti-oxidative system present in microglia. All these data support the development of NLC composed of functional lipids, and surface modified with different moieties, to target and treat CNS related disorders