RESUMO
Endothelial progenitor cells (EPCs) are being investigated for advanced therapies, and matrix metalloproteinase 9 (MMP9) has an important role in stroke recovery. Our aim was to determine whether tissue MMP9 influences the EPC-induced angiogenesis after ischemia. Wild-type (WT) and MMP9-deficient mice (MMP9/KO) were subjected to cerebral ischemia and treated with vehicle or outgrowth EPCs. After 3 weeks, we observed an increase in the peri-infarct vessel density in WT animals but not in MMP9/KO mice; no differences were found in the vehicle-treated groups. Our data suggest that tissue MMP9 has a crucial role in EPC-induced vascular remodeling after stroke.
Assuntos
Isquemia Encefálica/genética , Córtex Cerebral/patologia , Veias Cerebrais/fisiologia , Células Progenitoras Endoteliais , Metaloproteinase 9 da Matriz/fisiologia , Transplante de Células-Tronco/métodos , Remodelação Vascular , Animais , Isquemia Encefálica/patologia , Isquemia Encefálica/terapia , Infarto Cerebral/patologia , Infarto Cerebral/fisiopatologia , Veias Cerebrais/crescimento & desenvolvimento , Proteínas de Ligação a DNA , Proteínas do Domínio Duplacortina , Imageamento por Ressonância Magnética , Masculino , Metaloproteinase 9 da Matriz/deficiência , Metaloproteinase 9 da Matriz/genética , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/fisiologia , Neovascularização Fisiológica/genética , Neovascularização Fisiológica/fisiologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Neuropeptídeos/genética , Neuropeptídeos/fisiologia , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Acidente Vascular Cerebral/terapiaRESUMO
We synthesize highly crystalline citrate-coated iron oxide superparamagnetic nanoparticles that are stable and readily dispersible in water by an extremely fast microwave-assisted route and investigate the uptake of magnetic nanoparticles by endothelial cells. Nanoparticles form large aggregates when added to complete endothelial cell medium. The size of the aggregates was controlled by adjusting the ionic strength of the medium. The internalization of nanoparticles into endothelial cells was then investigated by transmission electron microscopy, magnetometry and chemical analysis, together with cell viability assays. Interestingly, a sevenfold more efficient uptake was found for systems with larger nanoparticle aggregates, which also showed significantly higher magnetic resonance imaging effectiveness without compromising cell viability and functionality. We are thus presenting an example of a straightforward microwave synthesis of citrate-coated iron oxide nanoparticles for safe endothelial progenitor cell labeling and good magnetic resonance cell imaging with potential application for magnetic cell guidance and in vivo cell tracking.
Assuntos
Rastreamento de Células/métodos , Dextranos/química , Células Progenitoras Endoteliais/química , Células Progenitoras Endoteliais/citologia , Imageamento por Ressonância Magnética/métodos , Nanopartículas de Magnetita/química , Água/química , Animais , Ácido Cítrico/química , Meios de Contraste/química , Difusão , Composição de Medicamentos/métodos , Células Endoteliais , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Micro-Ondas , Tamanho da Partícula , Coloração e Rotulagem/métodosRESUMO
Endothelial progenitor cells (EPCs) represent a promising approach for cell-based therapies to induce tissue repair; however, their effective delivery into the brain has remained a challenge. We loaded EPCs with superparamagnetic iron oxide nanoparticles (SPIONs), assessed their angiogenic potential and evaluated their guidance to the brain using an external magnet. SPIONs were stored in the cytoplasm within endosomes/lysosomes as observed by transmission electron microscopy (TEM) and could be visualized as hypointense signals by magnetic resonance imaging (MRI) T2-weighted images. In vitro SPION-loaded EPCs were fully functional, forming vessel-like structures in Matrigel®, and displayed enhanced migration and secretion of growth factors (VEGF and FGF), which was associated with a moderate increase in reactive oxygen species production. Furthermore, in vivo MRI of treated mice showed accumulated hypointense signals consistent with SPION-loaded EPCs engraftment. Thus, we demonstrate that loading EPCs with SPIONs represents a safe and effective strategy for precise cell guidance into specific brain areas. FROM THE CLINICAL EDITOR: This study investigates the potential role of endothelial progenitor cells in neuro-repair strategies of the central nervous system using SPION-loaded EPCs and magnetic guidance to the target organ. The authors demonstrate ex vivo cellular viability and maintained function following SPION load as well as successful guidance of the EPCs to the target site via MR imaging in a murine model.