Browsing by Author "Ferreira, Raquel"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- A brief overview of the oral delivery of insulin as an alternative to the parenteral deliveryPublication . Macedo, Ana; Filipe, Patricia; Thome, Natalia G.; Vieira, Joao; Oliveira, Carolina; Teodosio, Catarina; Ferreira, Raquel; Roque, Luis; Fonte, PedroDiabetes mellitus greatly affects the quality of life of patients and has a worldwide prevalence. Insulin is the most commonly used drug to treat diabetic patients and is usually administered through the subcutaneous route. However, this route of administration is ineffective due to the low concentration of insulin at the site of action. This route of administration causes discomfort to the patient and increases the risk of infection due to skin barrier disturbance caused by the needle. The oral administration of insulin has been proposed to surpass the disadvantages of subcutaneous administration. In this review, we give an overview of the strategies to deliver insulin by the oral route, from insulin conjugation to encapsulation into nanoparticles. These strategies are still under development to attain efficacy and effectiveness that are expected to be achieved in the near future.
- Blue light potentiates neurogenesis induced by retinoic acid-loaded responsive nanoparticlesPublication . Santos, Tiago; Ferreira, Raquel; Quartin, Emanuel; Boto, Carlos; Saraiva, Claudia; Bragança, José; Peca, Joao; Rodrigues, Cecilia; Ferreira, Lino; Bernardino, LilianaNeurogenic niches constitute a powerful endogenous source of new neurons that can be used for brain repair strategies. Neuronal differentiation of these cells can be regulated by molecules such as retinoic acid (RA) or by mild levels of reactive oxygen species (ROS) that are also known to upregulate RA receptor alpha (RAR alpha) levels. Data showed that neural stem cells from the subventricular zone (SVZ) exposed to blue light (405 nm laser) transiently induced NADPH oxidase-dependent ROS, resulting in beta-catenin activation and neuronal differentiation, and increased RAR alpha levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis both in vitro and in vivo, while offering a temporal and spatial control of RA release. In conclusion, this combinatory treatment offers great advantages to potentiate neuronal differentiation, and provides an innovative and efficient application for brain regenerative therapies. Statement of Significance Controlling the differentiation of stem cells would support the development of promising brain regenerative therapies. Blue light transiently increased reactive oxygen species, resulting in neuronal differentiation and increased retinoic acid receptor (RAR alpha) levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis, while offering a temporal and spatial control of RA release. In this sense, our approach relying on the modulation of endogenous stem cells for the generation of new neurons may support the development of novel clinical therapies. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
- Histamine stimulates neurogenesis in the rodent subventricular zonePublication . Bernardino, Liliana; Eiriz, Maria Francisca; Santos, Tiago; Xapelli, Sara; Grade, Sofia; Rosa, Alexandra Isabel; Cortes, Luisa; Ferreira, Raquel; Bragança, José; Agasse, Fabienne; Ferreira, Lino; Malva, Joao O.Neural stem/progenitor cells present in the subventricular zone (SVZ) are a potential source of repairing cells after injury. Therefore, the identification of novel players that modulate neural stem cells differentiation can have a huge impact in stem cell-based therapies. Herein, we describe a unique role of histamine in inducing functional neuronal differentiation from cultured mouse SVZ stem/progenitor cells. This proneurogenic effect depends on histamine 1 receptor activation and involves epigenetic modifications and increased expression of Mash1, Dlx2, and Ngn1 genes. Biocompatible poly (lactic-co-glycolic acid) microparticles, engineered to release histamine in a controlled and prolonged manner, also triggered robust neuronal differentiation in vitro. Preconditioning with histamine-loaded microparticles facilitated neuronal differentiation of SVZ-GFP cells grafted in hippocampal slices and in in vivo rodent brain. We propose that neuronal commitment triggered by histamine per se or released from biomaterial-derived vehicles may represent a new tool for brain repair strategies. STEM CELLS 2012; 30:773784