Síndrome do anticorpo antifosfolípide e fatores de risco para doença cerebrovascular isquêmica

Resumo: A síndrome do anticorpo antifosfolípide (SAAF) é caracterizada por tromboses de repetição sendo o acidente vascular cerebral isquêmico (AVCi) uma de suas principais complicações. Os mecanismos da doença cerebrovascular na SAAF não estão totalmente estabelecidos. O objetivo deste estudo foi verificar quais mecanismos poderiam estar envolvidos nesse processo, com ênfase no papel da embolia paradoxal (EP). Métodos: 53 pacientes com SAAF foram avaliados clinicamente e por meio de Doppler transcraniano contrastado (DTCc). Resultados: 23 pacientes com AVCi (grupo AVC) e 30 sem história de AVCi (Grupo controle). Fatores de risco tradicionais para doença cerebrovascular (hipertensão, diabetes, dislipidemia), aterosclerose de grandes vasos e alterações cardíacas não foram diferentes entre os grupos. Também não houve diferença na prevalência de shunt direita esquerda (SDE) entre os grupos. No entanto quando consideramos apenas pacientes com SAAF sem AVCi os escores de testes cognitivos foram melhores em pacientes sem SDE significativo. Conclusões: A EP não parece ser uma causa importante de AVCi em pacientes com SAAF, podendo estar relacionada, no entanto, a outros achados comuns na síndrome como por exemplo déficit cognitivo

Biomateriais na reparação do sistema nervoso central: uso de nanofibras sintéticas biodegradáveis como suporte para transplante celular e nanopartículas contendo cxcl12 no recrutamento de células-tronco endógenas

Central nervous system (CNS) disorders are highly debilitating and with few therapeutic options. Stem cells are a therapeutic promise for these diseases. The two main strategies described in literature are exogenous stem cells transplantation and enhancement of endogenous neurogenesis. Since both strategies pose problems, there is increasing research on the use of biomaterial to try to optimize cell engraftment and delivery of soluble factors that can increase neurogenesis. In this study, we evaluated polylactic acid (PLA) polymeric nanofibers (PNF) as carriers for cell transplantation and evaluated two formulations of poly(lactic-co-glycolic acid) (PLGA) for local delivery of CXCL12, a powerful chemokine to recruit neural stem cells (NSC). PNF were produced by jet-rotatory spinning and characterized by scanning electron microscopy. MSC and NSC obtained respectively from bone marrow and subventricular zone of C57BL/6 adult mice were cultured on PNF and transplanted into the brain of adult mice submitted to ischemic stroke model. Both cell types were viable when cultured on PNF, and MSC but not NSC were able to reduce the necrotic area. CXCL12 formulations were made by double emulsion. Two formulations were evaluated: microspheres (MS) and nanoparticles (NP). Both were able to encapsulate more than 80% of CXCL12, but showed different release profiles, with 100% CXCL12 released after 6 days for MS and 25% CXCL12 released after 2 weeks for NP. CXCL12 bioactivity was demonstrated by chemotaxis assay. When injected into the brains of mice submitted to traumatic brain injury model, only NP-CXCL12 induced CTN migration to the injured area. We conclude that the PNF are viable scaffolds for cell transplantation, MS and NP are suitable for soluble factor, such as CXCL12, delivery in two different brains injury model. Thus, we suggest that both approaches presented in this work could be tested as therapeutic strategies for CNS injuries.Doenças do sistema nervoso central (SNC) são altamente incapacitantes e com poucas opções de tratamento. A terapia com células-tronco é uma promessa terapêutica para essas doenças. As duas principais estratégias descritas na literatura são transplante de células-tronco exógenas e aumento da neurogênese endógena. Uma vez que ambas as estratégias estão sujeitas a problemas, tem crescido na literatura estudos sobre o uso de biomateriais com o intuito de otimizar a implantação das células transplantadas e a entrega de fatores solúveis que aumentem a resposta neurogênica. Neste trabalho avaliamos nanofibras poliméricas (NFP) de ácido poliláctico (PLA) como carreadores de células-tronco em procedimentos de transplante celular e avaliamos duas formulações de poli(láctico-co-ácido-glicólico) (PLGA) para entrega local de CXCL12, uma potente quimiocina para recrutamento de células-tronco neurais (CTN). As NFP foram produzidas por rotofiação e caracterizadas por microscopia eletrônica de varredura. As CTM e CTN obtidas, respectivamente, a partir de medula óssea e zona subventricular de camundongos adultos C57BL/6 foram cultivadas sobre as NFP e transplantadas no cérebro de camundongos adultos submetidos a um modelo acidente vascular encefálico isquêmico (AVCi). Ambos os tipos celulares se mostraram viáveis quando cultivados sobre NFP. As CTM, mas não as CTN, transplantadas no modelo animal, foram capazes de reduzir o volume da área necrótica. As formulações de CXCL12 foram produzidas por dupla emulsão. Duas formulações foram avaliadas: microesferas (MS) e nanopartículas (NP). Ambas foram capazes de encapsular mais do que 80% de CXCL12, mas apresentaram diferentes perfis de liberação, com 100% de CXCL12 liberado após 6 dias para o MS e 25% de CXCL12 liberado após 2 semanas para NP. A bioatividade do CXCL12 liberado das MS e NP foi confirmada por ensaio de quimiotaxia. Quando injetadas em cérebros de camundongos no modelo de traumatismo crânio-encefálico (TCE), apenas as NP-CXCL12 induziram aumento de migração de CTN para a área lesada. Concluímos que as NFP são suportes viáveis para transplante celular, MS e NP são viáveis para entrega de fatores solúveis, como o CXCL12, em dois modelos diferentes de lesão no SNC. Sendo assim, sugerimos que as duas abordagens apresentadas neste trabalho poderiam ser testadas como estratégias terapêuticas para lesões no SNC.Dados abertos - Sucupira - Teses e dissertações (2013 a 2016

Data for “<b>Modeling subarachnoid hemorrhage </b><b><i>in vitro</i></b><b>: an exploratory analysis of brain microvascular endothelial cells gene expression modulation by astrocytes”</b>

Submitted to Fluids and Barriers of the CNS</p

Right-to-left shunt and the hypercoagulable state: does paradoxical embolism play a role in patients with antiphospholipid syndrome and stroke?

OBJECTIVE: Patent foramen ovale is associated with paradoxical embolism (PE) and stroke. Hypercoagulable states, such as antiphospholipid syndrome (APS), can exacerbate PE by increasing clot formation. The aim of this study was to verify whether patients with APS and stroke present a right-to-left shunt (RLS) with greater frequency than patients with APS but without stroke. METHODS: Fifty-three patients with APS were tested for RLS using contrast-enhanced transcranial Doppler (cTCD): 23 patients had a history of stroke (Stroke Group) and 30 had no history of stroke (No-stroke Group). RESULTS: cTCD was positive in 15 patients (65%) from the Stroke Group and in 16 patients (53%) in the No-stroke Group (p=0.56). The proportion of patients with a small RLS (10 HITS) was similar between the groups without significant difference. CONCLUSIONS: Our data do not support the theory that paradoxical embolism may play an important role in stroke in APS patients

Protocol for designing and bioprinting multi-layered constructs to reconstruct an endothelial-epithelial 3D model

Summary: 3D bioprinting has opened new possibilities and elevated tissue engineering complexity. Here, we present a protocol to design a 3D model with two cell lineage layers (A549 and HUVEC) to recreate multi-cell constructs. We describe the steps for slicing the constructs, handling hydrogels, and detailing the bioprinting setup. These 3D-bioprinted constructs can be adapted to various cell models—from primary cell cultures to commercial cell lines and induced pluripotent stem cells (IPCs)—and applications, including drug screening and disease modeling.For complete details on the use and execution of this protocol, please refer to Cruz et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

A Gelatin Methacrylate-Based Hydrogel as a Potential Bioink for 3D Bioprinting and Neuronal Differentiation

Neuronal loss is the ultimate pathophysiologic event in central nervous system (CNS) diseases and replacing these neurons is one of the most significant challenges in regenerative medicine. Providing a suitable microenvironment for new neuron engraftment, proliferation, and synapse formation is a primary goal for 3D bioprinting. Among the various biomaterials, gelatin methacrylate (GelMA) stands out due to its Arg-Gly-Asp (RGD) domains, which assure its biocompatibility and degradation under physiological conditions. This work aimed to produce different GelMA-based bioink compositions, verify their mechanical and biological properties, and evaluate their ability to support neurogenesis. We evaluated four different GelMA-based bioink compositions; however, when it came to their biological properties, incorporating extracellular matrix components, such as GeltrexTM, was essential to ensure human neuroprogenitor cell viability. Finally, GeltrexTM: 8% GelMA (1:1) bioink efficiently maintained human neuroprogenitor cell stemness and supported neuronal differentiation. Interestingly, this bioink composition provides a suitable environment for murine astrocytes to de-differentiate into neural stem cells and give rise to MAP2-positive cells