RESUMO
BACKGROUND: A paucity of data exists to inform the use of interleukin (IL)-6 receptor antibodies (anti-IL-6) in pregnancy, particularly in the third trimester. This study aimed to describe outcomes of pregnant women and their neonates exposed to these medications given after the first trimester to treat COVID-19. METHODS: In this retrospective cohort study, we included all women with COVID-19 who were treated with an anti-IL-6 during pregnancy at two tertiary hospitals in London, UK-Guy's and St Thomas' NHS Foundation Trust and Imperial College Healthcare NHS Trust-between March 1, 2020, and Sept 30, 2022. Maternal demographics, clinical data, administered medications, and maternal and neonatal outcomes were assessed for all included women via a review of medical records and through maternal medicine networks. FINDINGS: 25 women received an anti-IL-6 for COVID-19 in pregnancy during the study period and were followed up for 12 months. The group described were a population at high risk, with 24 requiring level two or three critical care. 24 women received tocilizumab and one received sarilumab. All women were prescribed at least three concomitant medications. 16 received the anti-IL-6 in the third trimester of pregnancy and nine during the seocnd trimester. There were no women with maternal neutropenia or pancytopenia; increases in liver enzymes in 16 of 20 women with available alanine aminotransferase data were in keeping with the severity of COVID-19 reported and all three women who developed a secondary bacterial infection mounted a C-reactive protein response. There was one maternal death due to COVID-19. All pregnancies resulted in livebirths and there was one twin pregnancy. 16 of 26 babies were born preterm. One baby died at age 6 months due to complications of extreme prematurity. A transient neonatal cytopenia was described in six of 19 babies in whom a full blood count was performed. Although these findings are likely to be in keeping with prematurity alone, we cannot exclude the possibility that transplacental transfer of anti-IL-6 was contributory. INTERPRETATION: We report further data on the use of anti-IL-6 in the second and third trimesters of pregnancy for the management of COVID-19. When extrapolated, our data can inform shared decision making for individuals who would benefit from the use of anti-IL-6 into the third trimester of pregnancy for management of rheumatological disease. FUNDING: None.
Assuntos
COVID-19 , Complicações Infecciosas na Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Humanos , Feminino , Gravidez , Estudos Retrospectivos , Adulto , COVID-19/imunologia , Complicações Infecciosas na Gravidez/tratamento farmacológico , Tratamento Farmacológico da COVID-19 , Receptores de Interleucina-6/antagonistas & inibidores , Receptores de Interleucina-6/imunologia , Recém-Nascido , Anticorpos Monoclonais Humanizados/uso terapêutico , SARS-CoV-2/imunologia , Resultado da Gravidez/epidemiologiaRESUMO
Progress towards universal health coverage is monitored by the incidence of catastrophic spending. Two catastrophic spending indicators are commonly used in Europe: Sustainable Development Goal (SDG) indicator 3.8.2 and the WHO Regional Office for Europe (WHO/Europe) indicator. The use of different indicators can cause confusion, especially if they produce contradictory results and policy implications. We use harmonised household budget survey data from 27 European Union countries covering 505,217 households and estimate the risk of catastrophic spending, conditional on household characteristics and the design of medicines co-payments. We calculate the predicted probability of catastrophic spending for particular households, which we call LISAs, under combinations of medicines co-payment policies and compare predictions across the two indicators. Using the WHO/Europe indicator, any combination of two or more protective policies (i.e. low fixed co-payments instead of percentage co-payments, exemptions for low-income households and income-related caps on co-payments) is associated with a statistically significant lower risk of catastrophic spending. Using the SDG indicator, confidence intervals for every combination of protective policies overlap with those for no protective policies. Although out-of-pocket medicines spending is a strong predictor of catastrophic spending using both indicators, the WHO/Europe indicator is more sensitive to medicines co-payment policies than the SDG indicator, making it a better indicator to monitor health system equity and progress towards UHC in Europe.
Assuntos
Gastos em Saúde , Cobertura Universal do Seguro de Saúde , Humanos , Europa (Continente) , Gastos em Saúde/estatística & dados numéricos , Cobertura Universal do Seguro de Saúde/economia , Política de Saúde , Financiamento Pessoal , Características da Família , Doença Catastrófica/economiaRESUMO
Body mass results from a complex interplay between genetics and environment. Previous studies of the genetic contribution to body mass have excluded repetitive regions due to the technical limitations of platforms used for population scale studies. Here we apply genome-wide approaches, identifying an association between adult body mass and the copy number (CN) of 47S-ribosomal DNA (rDNA). rDNA codes for the 18 S, 5.8 S and 28 S ribosomal RNA (rRNA) components of the ribosome. In mammals, there are hundreds of copies of these genes. Inter-individual variation in the rDNA CN has not previously been associated with a mammalian phenotype. Here, we show that rDNA CN variation associates with post-pubertal growth rate in rats and body mass index in adult humans. rDNA CN is not associated with rRNA transcription rates in adult tissues, suggesting the mechanistic link occurs earlier in development. This aligns with the observation that the association emerges by early adulthood.
Assuntos
Índice de Massa Corporal , Variações do Número de Cópias de DNA , DNA Ribossômico , Animais , Humanos , DNA Ribossômico/genética , Masculino , Ratos , Feminino , Adulto , Mamíferos/genética , RNA Ribossômico/genética , RNA Ribossômico/metabolismoRESUMO
Background: Ensuring that access to health care is affordable for everyone-financial protection-is central to universal health coverage (UHC). Financial protection is commonly measured using indicators of financial barriers to access (unmet need for health care) and financial hardship caused by out-of-pocket payments for health care (impoverishing and catastrophic health spending). We aim to assess financial hardship and unmet need in Europe and identify the coverage policy choices that undermine financial protection. Methods: We carry out a cross-sectional study of financial hardship in 40 countries in Europe in 2019 (the latest available year of data before COVID-19) using microdata from national household budget surveys. We define impoverishing health spending as out-of-pocket payments that push households below or further below a relative poverty line and catastrophic health spending as out-of-pocket payments that exceed 40% of a household's capacity to pay for health care. We link these results to survey data on unmet need for health care, dental care, and prescribed medicines and information on two aspects of coverage policy at country level: the main basis for entitlement to publicly financed health care and user charges for covered services. Findings: Out-of-pocket payments for health care lead to financial hardship and unmet need in every country in the study, particularly for people with low incomes. Impoverishing health spending ranges from under 1% of households (in six countries) to 12%, with a median of 3%. Catastrophic health spending ranges from under 1% of households (in two countries) to 20%, with a median of 6%. Catastrophic health spending is consistently concentrated in the poorest fifth of the population and is largely driven by out-of-pocket payments for outpatient medicines, medical products, and dental care-all forms of treatment that should be an essential part of primary care. The median incidence of catastrophic health spending is three times lower in countries that cover over 99% of the population than in countries that cover less than 99%. In 16 out of the 17 countries that cover less than 99% of the population, the basis for entitlement is payment of contributions to a social health insurance (SHI) scheme. Countries that give greater protection from user charges to people with low incomes have lower levels of catastrophic health spending. Interpretation: It is challenging to identify with certainty the coverage policy choices that undermine financial protection due to the complexity of the policies involved and the difficulty of disentangling the effects of different choices. The conclusions we draw are therefore tentative, though plausible. Countries are more likely to move towards UHC if they reduce out-of-pocket payments in a progressive way, decreasing them for people with low incomes first. Coverage policy choices that seem likely to achieve this include de-linking entitlement from payment of SHI contributions; expanding the coverage of outpatient medicines, medical products, and dental care; limiting user charges; and strengthening protection against user charges, particularly for people with low incomes. Funding: The European Union (DG SANTE and DG NEAR) and the Government of the Autonomous Community of Catalonia, Spain.
RESUMO
Research has shown that multidimensional approaches to Chagas disease (CD), integrating its biomedical and psycho-socio-cultural components, are successful in enhancing early access to diagnosis, treatment and sustainable follow-up.For the first time, a consulate was selected for a community-based CD detection campaign. Two different strategies were designed, implemented and compared between 2021 and 2022 at the Consulate General of Bolivia and a reference health facility in Barcelona open to all Bolivians in Catalonia.Strategy 1 consisted in CD awareness-raising activities before referring those interested to the reference facility for infectious disease screening. Strategy 2 offered additional in-situ serological CD screening. Most of the 307 participants were Bolivian women residents in Barcelona. In strategy 1, 73 people (35.8% of those who were offered the test) were screened and 19.2% of them were diagnosed with CD. Additionally, 53,4% completed their vaccination schedules and 28.8% were treated for other parasitic infections (strongyloidiasis, giardiasis, eosinophilia, syphilis). In strategy 2, 103 people were screened in-situ (100% of those who were offered the test) and 13.5% received a CD diagnosis. 21,4% completed their vaccination schedule at the reference health facility and 2,9% were referred for iron deficiency anemia, strongyloidiasis or chronic hepatitis C.The fact that the screening took place in an official workplace of representatives of their own country, together with the presence of community-based participants fueled trust and increased CD understanding. Each of the strategies assessed had different benefits. Opportunities for systematic integration for CD based on community action in consulates may enhance early access to diagnosis, care and disease prevention.
Assuntos
Doença de Chagas , Eosinofilia , Estrongiloidíase , Humanos , Feminino , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Programas de Rastreamento , Participação da ComunidadeRESUMO
Signaling through the inflammasome is important for the inflammatory response. Low concentrations of intracellular K+ are associated with the specific oligomerization and activation of the NLRP3 inflammasome, a type of inflammasome involved in sterile inflammation. After NLRP3 oligomerization, ASC protein binds and forms oligomeric filaments that culminate in large protein complexes named ASC specks. ASC specks are also initiated from different inflammasome scaffolds, such as AIM2, NLRC4, or Pyrin. ASC oligomers recruit caspase-1 and then induce its activation through interactions between their respective caspase activation and recruitment domains (CARD). So far, ASC oligomerization and caspase-1 activation are K+-independent processes. Here, we found that when there is low intracellular K+, ASC oligomers change their structure independently of NLRP3 and make the ASCCARD domain more accessible for the recruitment of the pro-caspase-1CARD domain. Therefore, conditions that decrease intracellular K+ not only drive NLRP3 responses but also enhance the recruitment of the pro-caspase-1 CARD domain into the ASC specks.
Assuntos
Proteínas Adaptadoras de Sinalização CARD , Caspase 1 , Inflamassomos , Potássio , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Caspase 1/genética , Caspase 1/metabolismo , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Potássio/metabolismo , Domínios ProteicosRESUMO
BACKGROUND: The radio- and chemo-resistance of glioblastoma stem-like cells (GSCs), together with their innate tumor-initiating aptitude, make this cell population a crucial target for effective therapies. However, targeting GSCs is hardly difficult and complex, due to the presence of the blood-brain barrier (BBB) and the infiltrative nature of GSCs arousing their dispersion within the brain parenchyma. METHODS: Liposomes (LIPs), surface-decorated with an Apolipoprotein E-modified peptide (mApoE) to enable BBB crossing, were loaded with doxorubicin (DOXO), as paradigm of cytotoxic drug triggering immunogenic cell death (ICD). Patient-derived xenografts (PDXs) obtained by GSC intracranial injection were treated with mApoE-DOXO-LIPs alone or concomitantly with radiation. RESULTS: Our results indicated that mApoE, through the engagement of the low-density lipoprotein receptor (LDLR), promotes mApoE-DOXO-LIPs transcytosis across the BBB and confers target specificity towards GSCs. Irradiation enhanced LDLR expression on both BBB and GSCs, thus further promoting LIP diffusion and specificity. When administered in combination with radiations, mApoE-DOXO-LIPs caused a significant reduction of in vivo tumor growth due to GSC apoptosis. GSC apoptosis prompted microglia/macrophage phagocytic activity, together with the activation of the antigen-presenting machinery crucially required for anti-tumor adaptive immune response. CONCLUSIONS: Our results advocate for radiotherapy and adjuvant administration of drug-loaded, mApoE-targeted nanovectors as an effective strategy to deliver cytotoxic molecules to GSCs at the surgical tumor margins, the forefront of glioblastoma (GBM) recurrence, circumventing BBB hurdles. DOXO encapsulation proved in situ immune response activation within GBM microenvironment.
RESUMO
Este estudio tiene por objetivo valorar el nivel de evidencia científica que existe sobre los beneficios del ejercicio físico a corto y largo plazo para la salud de la población. Las Enfermedades Crónicas No Transmisibles (ECNT) son enfermedades de larga duración cuya evolución es generalmente lenta. Estas enfermedades representan una verdadera epidemia que va en aumento debido al envejecimiento de la población y los estilos de vida actuales que acentúan el sedentarismo y la mala alimentación. El ejercicio y la actividad física juegan un rol fundamental en la prevención de Enfermedades Crónicas No Transmisibles, disminuyen el riesgo de mortalidad y eventos cardiovasculares mayores. El ejercicio físico actúa como mediador entre el alimento ingerido y la energía que debería gastarse. Se ha demostrado que el ejercicio puede mediar en la lucha contra la inflamación, siendo la piedra angular en la prevención de enfermedades que cursan con inflamación crónica
ABSTRACT: This study aims to assess the level of scientific evidence that exists on the benefits of short and long term physical exercise for the health of the population. Chronic Noncommunicable Diseases (NCDs) are long-term diseases whose evolution is generally slow. These diseases represent a true epidemic that is increasing due to the aging of the population and the current lifestyles that accentuate sedentary lifestyle and poor diet. Exercise and physical activity play a fundamental role in the prevention of noncommunicable chronic diseases, reduce the risk of mortality and major cardiovascular events. Physical exercise acts as a mediator between the food eaten and the energy that should be spent. It has been shown that exercise can mediate in the fight against inflammation, being the cornerstone in the prevention of diseases that occur with chronic inflammation
RESUMO: Este estudo tem como objetivo avaliar o nível de evidência científica que existe sobre os benefícios do exercício físico de curto e longo prazo para a saúde da população. As Doenças Crônicas Não Transmissíveis (DNTs) são doenças de longa duração cuja evolução é geralmente lenta. Essas doenças representam uma verdadeira epidemia que está aumentando devido ao envelhecimento da população e aos estilos de vida atuais que acentuam o estilo de vida sedentário e a dieta pobre. Exercício e atividade física desempenham um papel fundamental na prevenção de doenças crônicas não transmissíveis, reduzindo o risco de mortalidade e eventos cardiovasculares maiores. O exercício físico atua como um mediador entre o alimento ingerido e a energia que deve ser consumida. Tem sido demonstrado que o exercício pode mediar a luta contra a inflamação, sendo a pedra angular na prevenção de doenças que ocorrem com inflamação crônica
Assuntos
Humanos , Exercício Físico , Doença Crônica , Prevenção de Doenças , Doença , Doenças não Transmissíveis , Atividade MotoraRESUMO
BACKGROUND: Multi-target drugs have gained significant recognition for the treatment of multifactorial diseases such as depression. Under a screening study of multi-potent medicinal plants with claimed antidepressant-like activity, the phenolic-rich Annona muricata aqueous extract (AE) emerged as a moderate monoamine oxidase A (hMAO-A) inhibitor and a strong hydrogen peroxide (H2O2) scavenger. PURPOSE: In order to protect this extract from gastrointestinal biotransformation and to improve its permeability across the blood-brain barrier (BBB), four phospholipid nanoformulations of liposomes and phytosomes functionalized with a peptide ligand promoting BBB crossing were produced. METHODS: AE and nanoformulations were characterized by HPLC-DAD-ESI-MSn, HPLC-DAD, spectrophotometric, fluorescence and dynamic light scattering methods. Cytotoxicity and permeability studies were carried out using an in vitro transwell model of the BBB, composed of immortalized human microvascular endothelial cells (hCMEC/D3), and in vitro hMAO-A inhibition and H2O2 scavenging activities were performed with all samples. RESULTS: The encapsulation/binding of AE was more efficient with phytosomes, while liposomes were more stable, displaying a slower extract release over time. In general, phytosomes were less toxic than liposomes in hCMEC/D3 cells and, when present, cholesterol improved the permeability across the cell monolayer of all tested nanoformulations. All nanoformulations conserved the antioxidant potential of AE, while phosphatidylcholine interfered with MAO-A inhibition assay. CONCLUSIONS: Overall, phytosome formulations registered the best performance in terms of binding efficiency, enzyme inhibition and scavenging activity, thus representing a promising multipotent phenolic-rich nanoshuttle for future in vivo depression treatment.
Assuntos
Annona/química , Antioxidantes/farmacologia , Portadores de Fármacos/química , Lipossomos/química , Extratos Vegetais/administração & dosagem , Barreira Hematoencefálica/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Portadores de Fármacos/administração & dosagem , Células Endoteliais/efeitos dos fármacos , Sequestradores de Radicais Livres/farmacologia , Humanos , Peróxido de Hidrogênio/metabolismo , Lipossomos/administração & dosagem , Inibidores da Monoaminoxidase/farmacologia , Nanoestruturas/administração & dosagem , Nanoestruturas/química , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
The evolution and occurrence of fossil sea turtles at the Pacific margin of South America is poorly known and restricted to Neogene (Miocene/Pliocene) findings from the Pisco Formation, Peru. Here we report and describe the first record of Oligocene (late Oligocene, â¼24 Ma) Pan-Cheloniidae sea turtle remains of South America. The fossil material corresponds to a single, isolated and well-preserved costal bone found at the Montañita/Olón locality, Santa Elena Province, Ecuador. Comparisons with other Oligocene and extant representatives allow us to confirm that belongs to a sea turtle characterized by: lack of lateral ossification, allowing the dorsal exposure of the distal end of ribs; dorsal surface of bone sculptured, changing from dense vermiculation at the vertebral scute region to anastomosing pattern of grooves at the most lateral portion of the costal. This fossil finding shows the high potential that the Ecuadorian Oligocene outcrops have in order to explore the evolution and paleobiogeography distribution of sea turtles by the time that the Pacific and the Atlantic oceans were connected via the Panama basin.
RESUMO
A new small probable Oligocene dolphin from Ecuador represents a new genus and species, Urkudelphis chawpipacha. The new taxon is known from a single juvenile skull and earbones; it differs from other archaic dolphins in features including widely exposed frontals at the vertex, a dorsally wide open vomer at the mesorostral groove, and a strongly projected and pointed lateral tuberosity of the periotic. Phylogenetic analysis places it toward the base of the largely-extinct clade Platanistoidea. The fossil is one of a few records of tropical fossil dolphins.
Assuntos
Golfinhos/classificação , Fósseis , Animais , Golfinhos/anatomia & histologia , EquadorRESUMO
New Pleistocene fossilized turtle remains from five localities of western Ecuador (Santa Elena Province) are described here. All these shell (carapace and plastron) fossil remains come from the Tablazo Formation and belong to three different lineages of cryptodires ("hidden-necked" turtles). The most abundant remains belong to geoemydids, attributed here to the genus Rhinoclemmys (indeterminate species). Less abundant in occurrence are the kinosternidids, attributed to Kinosternon (indeterminate species), and the first fossil record of chelydrids, Chelydra(indeterminate species), in the entirety of Central and South America.
RESUMO
The accumulation of extracellular amyloid beta (Abeta42) both in brain and in cerebral vessels characterizes Alzheimer's disease (AD) pathogenesis. Recently, the possibility to functionalize nanoparticles (NPs) surface with Abeta42 binding molecules, making them suitable tools for reducing Abeta42 burden has been shown effective in models of AD. Aim of this work consisted in proving that NPs might be effective in sequestering Abeta42 in biological fluids, such as CSF and plasma. This demonstration is extremely important considering that these Abeta42 pools are in continuum with the brain parenchyma with drainage of Abeta from interstitial brain tissue to blood vessel and plasma. In this work, liposomes (LIP) were functionalized as previously shown in order to promote high-affinity Abeta binding, i.e., either with, phosphatidic acid (PA), or a modified Apolipoprotein E-derived peptide (mApo), or with a curcumin derivative (TREG); Abeta42 levels were determined by ELISA in CSF and plasma samples. mApo-PA-LIP (25 and 250 µM) mildly albeit significantly sequestered Abeta42 proteins in CSF samples obtained from healthy subjects (p < 0.01). Analogously a significant binding (â¼20%) of Abeta42 (p < 0.001) was demonstrated following exposure to all functionalized liposomes in plasma samples obtained from selected AD or Down's syndrome patients expressing high levels of Abeta42. The same results were obtained by quantifying Abeta42 content after removal of liposome-bound Abeta by using gel filtration chromatography or ultracentrifugation on a discontinuous sucrose density gradient. In conclusion, we demonstrate that functionalized liposomes significantly sequester Abeta42 in human biological fluids. These data may be critical for future in vivo administration tests using NPs for promoting sink effect.
Assuntos
Doença de Alzheimer/sangue , Doença de Alzheimer/líquido cefalorraquidiano , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Lipossomos/metabolismo , Fragmentos de Peptídeos/sangue , Fragmentos de Peptídeos/líquido cefalorraquidiano , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biomarcadores/líquido cefalorraquidiano , Feminino , Humanos , MasculinoRESUMO
Aggregation of amyloid-ß peptide (Aß) is a key event in the pathogenesis of Alzheimer's disease (AD). We investigated the effects of nanoliposomes decorated with the retro-inverso peptide RI-OR2-TAT (Ac-rGffvlkGrrrrqrrkkrGy-NH2) on the aggregation and toxicity of Aß. Remarkably low concentrations of these peptide inhibitor nanoparticles (PINPs) were required to inhibit the formation of Aß oligomers and fibrils in vitro, with 50% inhibition occurring at a molar ratio of ~1:2000 of liposome-bound RI-OR2-TAT to Aß. PINPs also bound to Aß with high affinity (Kd=13.2-50 nM), rescued SHSY-5Y cells from the toxic effect of pre-aggregated Aß, crossed an in vitro blood-brain barrier model (hCMEC/D3 cell monolayer), entered the brains of C57 BL/6 mice, and protected against memory loss in APPSWE transgenic mice in a novel object recognition test. As the most potent aggregation inhibitor that we have tested so far, we propose to develop PINPs as a potential disease-modifying treatment for AD.
Assuntos
Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/terapia , Nanopartículas , Fragmentos de Peptídeos , Peptídeos beta-Amiloides , Animais , Barreira Hematoencefálica , Humanos , Lipossomos , Camundongos Transgênicos , Células Tumorais CultivadasRESUMO
Surface functionalization with antitransferrin receptor (TfR) mAbs has been suggested as the strategy to enhance the transfer of nanoparticles (NPs) across the blood-brain barrier (BBB) and to carry nonpermeant drugs from the blood into the brain. However, the efficiency of BBB crossing is currently too poor to be used in vivo. In the present investigation, we compared 6 different murine mAbs specific for different epitopes of the human TfR to identify the best performing one for the functionalization of NPs. For this purpose, we compared the ability of mAbs to cross an in vitro BBB model made of human brain capillary endothelial cells (hCMEC/D3). Liposomes functionalized with the best performing mAb (MYBE/4C1) were uptaken, crossed the BBB in vitro, and facilitated the BBB in vitro passage of doxorubicin, an anticancer drug, 3.9 folds more than liposomes functionalized with a nonspecific IgG, as assessed by confocal microscopy, radiochemical techniques, and fluorescence, and did not modify the cell monolayer structural or functional properties. These results show that MYBE/4C1 antihuman TfR mAb is a powerful resource for the enhancement of BBB crossing of NPs and is therefore potentially useful in the treatment of neurologic diseases and disorders including brain carcinomas.
Assuntos
Anticorpos Bloqueadores/farmacologia , Barreira Hematoencefálica/efeitos dos fármacos , Receptores da Transferrina/antagonistas & inibidores , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacocinética , Capilares/efeitos dos fármacos , Capilares/metabolismo , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacocinética , Sistemas de Liberação de Medicamentos , Células Endoteliais , Epitopos , Humanos , Imunoglobulina G/química , Lipossomos , Camundongos , Tamanho da PartículaRESUMO
BACKGROUND: Amyloid ß (Aß) peptide aggregation is the main molecular mechanism underlying the development of Alzheimer's disease, the most widespread form of senile dementia worldwide. Increasing evidence suggests that the key factor leading to impaired neuronal function is accumulation of water-soluble Aß oligomers rather than formation of the senile plaques created by the deposition of large fibrillary aggregates of Aß. However, several questions remain about the preliminary steps and the progression of Aß oligomerization. METHODS: We show that the initial stages of the aggregation of fluorescently labeled Aß can be determined with a high degree of precision and at physiological (i.e., nanomolar) concentrations by using either steady-state fluorimetry or time-correlated single-photon counting. RESULTS: We study the dependence of the oligomerization extent and rate on the Aß concentration. We determine the chemical binding affinity of fluorescently labeled Aß for liposomes that have been recently shown to be pharmacologically active in vivo, reducing the Aß burden within the brain. We also probe their capacity to hinder the Aß oligomerization process in vitro. CONCLUSIONS: We introduced a fluorescence assay allowing investigation of the earliest steps of Aß oligomerization, the peptide involved in Alzheimer's disease. The assay proved to be sensitive even at Aß concentrations as low as those physiologically observed in the cerebrospinal fluid. GENERAL SIGNIFICANCE: This work represents an extensive and quantitative study on the initial events of Aß oligomerization at physiological concentration. It may enhance our comprehension of the molecular mechanisms leading to Alzheimer's disease, thus paving the way to novel therapeutic strategies.
Assuntos
Peptídeos beta-Amiloides/química , Lipossomos/química , Fragmentos de Peptídeos/química , Agregação Patológica de Proteínas , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Humanos , Fragmentos de Peptídeos/metabolismo , Espectrometria de FluorescênciaRESUMO
We previously showed the ability of liposomes bi-functionalized with phosphatidic acid and an ApoE-derived peptide (mApoE-PA-LIP) to reduce brain Aß in transgenic Alzheimer mice. Herein we investigated the efficacy of mApoE-PA-LIP to withdraw Aß peptide in different aggregation forms from the brain, using a transwell cellular model of the blood-brain barrier and APP/PS1 mice. The spontaneous efflux of Aß oligomers (Aßo), but not of Aß fibrils, from the 'brain' side of the transwell was strongly enhanced (5-fold) in presence of mApoE-PA-LIP in the 'blood' compartment. This effect is due to a withdrawal of Aßo exerted by peripheral mApoE-PA-LIP by sink effect, because, when present in the brain side, they did not act as Aßo carrier and limit the oligomer efflux. In vivo peripheral administration of mApoE-PA-LIP significantly increased the plasma Aß level, suggesting that Aß-binding particles exploiting the sink effect can be used as a therapeutic strategy for Alzheimer disease. From the Clinical Editor: Alzheimer disease (AD) at present is an incurable disease, which is thought to be caused by an accumulation of amyloid-ß (Aß) peptides in the brain. Many strategies in combating this disease have been focused on either the prevention or dissolving these peptides. In this article, the authors showed the ability of liposomes bi-functionalized with phosphatidic acid and with an ApoE- derived peptide to withdraw amyloid peptides from the brain. The data would help the future design of more novel treatment for Alzheimer disease.
Assuntos
Doença de Alzheimer/terapia , Peptídeos beta-Amiloides/isolamento & purificação , Peptídeos beta-Amiloides/metabolismo , Barreira Hematoencefálica/metabolismo , Nanopartículas/metabolismo , Nanopartículas/uso terapêutico , Doença de Alzheimer/metabolismo , Barreira Hematoencefálica/química , Células Cultivadas , Estudos de Viabilidade , Humanos , Nanopartículas/químicaRESUMO
In the search of new drug delivery carriers for the brain, self-assembled nanoparticles (NP) were prepared from poly(N,N-dimethylacrylamide)-block-polystyrene polymer. NP displayed biocompatibility on cultured endothelial cells, macrophages and differentiated SH-SY5Y neuronal-like cells. The surface-functionalization of NP with a modified fragment of human Apolipoprotein E (mApoE) enhanced the uptake of NP by cultured human brain capillary endothelial cells, as assessed by confocal microscopy, and their permeability through a Transwell Blood Brain Barrier model made with the same cells, as assessed by fluorescence. Finally, mApoE-NP embedding doxorubicin displayed an enhanced release of drug at low pH, suggesting the potential use of these NP for the treatment of brain tumors.