Communication from the periphery to the hypothalamus through the blood–brain barrier: An in vitro platform

Martins, João Pedro Poças; Alves, Cecília J.; Neto, Estrela; Lamghari, Meriem

doi:10.1016/j.ijpharm.2015.12.058

Cited by 8 publications

(7 citation statements)

References 48 publications

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“…The co-culture of bEnd.3 and rat primary astrocytes showed high membrane integrity with TEER values up to 79.7 ± 11.9 Ω.cm2, which was in accordance with previously reported data [26,39]. Regarding the permeability to NaF, the permeability coefficient values were in the order of 5.5 ± 0.5 cm/s, which also matched values found in previous work [40].…”

Section: A01/00supporting

confidence: 92%

“…An in vitro BBB model was established as previously reported [26]. Briefly, 0.4-μm pore-size transwells® were coated with collagen type-I (10 μg/cm2) and primary rat astrocytes were seeded onto the basolateral side of the membrane at 5.0 × 104 viable cells/cm2.…”

Section: In Vitro Bbb Modelmentioning

confidence: 99%

“…To understand the effect of PAMAM on the BBB, both in terms of its toxicity and capacity to permeate the barrier, a well-established in vitro model of the BBB [26] was reproduced using a coculture of mouse endothelial bEnd.3 cells and rat primary astrocytes on collagen-coated 0.4-μm pore-size transwell® membranes.…”

Section: A01/00mentioning

confidence: 99%

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PAMAM dendrimers: blood-brain barrier transport and neuronal uptake after focal brain ischemia

Santos

Martín

Leite

et al. 2018

Journal of Controlled Release

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Drug delivery to the central nervous system is restricted by the blood-brain barrier (BBB). However, with the onset of stroke, the BBB becomes leaky, providing a window of opportunity to passively target the brain. Here, cationic poly(amido amine) (PAMAM) dendrimers of different generations were functionalized with poly(ethylene glycol) (PEG) to reduce cytotoxicity and prolong blood circulation half-life, aiming for a safe in vivo drug delivery system in a stroke scenario. Rhodamine B isothiocyanate (RITC) was covalently tethered to the dendrimer backbone and used as a small surrogate drug as well as for tracking purposes. The biocompatibility of PAMAM was markedly increased by PEGylation as a function of dendrimer generation and degree of functionalization. The PEGylated RITC-modified dendrimers did not affect the integrity of an in vitro BBB model. Additionally, the functionalized dendrimers remained safe when in contact with the bEnd.3 cells and rat primary astrocytes composing the in vitro BBB model after hypoxia induced by oxygen-glucose deprivation. Modification with PEG also decreased the interaction and uptake by endothelial cells of PAMAM, indicating that the transport across a leaky Version: Postprint (identical content as published paper) This is a self-archived document from i3S-Instituto de Investigação e Inovação em Saúde in the University of Porto Open Repository For Open Access to more of our publications, please visit http://repositorio-aberto.up.pt/ A01/00 BBB due to focal brain ischemia would be facilitated. Next, the functionalized dendrimers were tested in contact with red blood cells showing no haemolysis for the PEGylated PAMAM, in contrast to the unmodified dendrimer. Interestingly, the PEG-modified dendrimers reduced blood clotting, which may be an added beneficial function in the context of stroke. The optimized PAMAM formulation was intravenously administered in mice after inducing permanent focal brain ischemia. Twenty-four hours after administration, dendrimers could be detected in the brain, including in neurons of the ischemic cortex. Our results suggest that the proposed formulation has the potential for becoming a successful delivery vector for therapeutic application to the injured brain after stroke reaching the ischemic neurons. Graphical abstract (A) PEG-conjugated PAMAM dendrimers bound with RITC diffusing through a 'leaky' blood brain barrier upon focal cerebral ischemia. (B) Modified PAMAM dendrimer identified in neurons at the site of the brain ischemic injury.

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Section: A01/00supporting

confidence: 92%

Section: In Vitro Bbb Modelmentioning

confidence: 99%

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PAMAM dendrimers: blood-brain barrier transport and neuronal uptake after focal brain ischemia

Santos

Martín

Leite

et al. 2018

Journal of Controlled Release

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“…Supporting this hypothesis is the evidence that insulin levels in the CSF are lower (about 25% less) of those circulating in blood and its concentrations increase after meals or with peripheral insulin infusion [ 7 ]. Another possibility is the evidence that there are regions of the brain, such as the hypothalamus, that lack an effective barrier, allowing insulin access to CNS [ 8 ]. A third hypothesis suggests that insulin is synthesized in the brain regions but this possibility requires further studies [ 3 , 9 ].…”

Section: Overview Of Insulin Signallingmentioning

confidence: 99%

Type 2 Diabetes Mellitus and Alzheimer’s Disease: Role of Insulin Signalling and Therapeutic Implications

Tumminia

Vinciguerra

Parisi

et al. 2018

IJMS

194

127

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In the last two decades, numerous in vitro studies demonstrated that insulin receptors and theirs downstream pathways are widely distributed throughout the brain. This evidence has proven that; at variance with previous believes; insulin/insulin-like-growth-factor (IGF) signalling plays a crucial role in the regulation of different central nervous system (CNS) tasks. The most important of these functions include: synaptic formation; neuronal plasticity; learning; memory; neuronal stem cell activation; neurite growth and repair. Therefore; dysfunction at different levels of insulin signalling and metabolism can contribute to the development of a number of brain disorders. Growing evidences demonstrate a close relationship between Type 2 Diabetes Mellitus (T2DM) and neurodegenerative disorders such as Alzheimer’s disease. They, in fact, share many pathophysiological characteristics comprising impaired insulin sensitivity, amyloid β accumulation, tau hyper-phosphorylation, brain vasculopathy, inflammation and oxidative stress. In this article, we will review the clinical and experimental evidences linking insulin resistance, T2DM and neurodegeneration, with the objective to specifically focus on insulin signalling-related mechanisms. We will also evaluate the pharmacological strategies targeting T2DM as potential therapeutic tools in patients with cognitive impairment.

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“…An important development in perspective is the more and more expanding use of microfluidic chambers to permit an optimal distribution of nutrients and/or to selectively target certain areas of the OC rather than the entire slice ( 26 ) and the development of devices for long term perfusion, imaging, and electrical interfacing ( 27 ). It is also of relevance the possibility to reconstruct in vitro the BBB and use it to condition the medium in which OCs are grown ( 28 ).…”

Section: Ex Vivo Rodent Platforms In Neuroscience Researchmentioning

confidence: 99%

The Use of ex Vivo Rodent Platforms in Neuroscience Translational Research With Attention to the 3Rs Philosophy

Lossi

Merighi

2018

Front. Vet. Sci.

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The principles of the 3Rs—Replacement, Reduction, and Refinement—are at the basis of most advanced national and supranational (EU) regulations on animal experimentation and welfare. In the perspective to reduce and refine the use of these animals in translational research, we here discuss the use of rodent acute and organotypically cultured central nervous system slices. We describe novel applications of these ex vivo platforms in medium-throughput screening of neuroactive molecules of potential pharmacological interest, with particular attention to more recent developments that permit to fully exploit the potential of direct genetic engineering of organotypic cultures using transfection techniques. We then describe the perspectives for expanding the use ex vivo platforms in neuroscience studies under the 3Rs philosophy using the following approaches: (1) Use of co-cultures of two brain regions physiologically connected to each other (source-target) to analyze axon regeneration and reconstruction of circuitries; (2) Microinjection or co-cultures of primary cells and/or cell lines releasing one or more neuroactive molecules to screen their physiological and/or pharmacological effects onto neuronal survival and slice circuitry. Microinjected or co-cultured cells are ideally made fluorescent after transfection with a plasmid construct encoding green or red fluorescent protein under the control of a general promoter such as hCMV; (3) Use of “sniffer” cells sensing the release of biologically active molecules from organotypic cultures by means of fluorescent probes. These cells can be prepared with activatable green fluorescent protein, a unique chromophore that remains in a “dark” state because its maturation is inhibited, and can be made fluorescent (de-quenched) if specific cellular enzymes, such as proteases or kinases, are activated.

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Communication from the periphery to the hypothalamus through the blood–brain barrier: An in vitro platform

Cited by 8 publications

References 48 publications

PAMAM dendrimers: blood-brain barrier transport and neuronal uptake after focal brain ischemia

PAMAM dendrimers: blood-brain barrier transport and neuronal uptake after focal brain ischemia

Type 2 Diabetes Mellitus and Alzheimer’s Disease: Role of Insulin Signalling and Therapeutic Implications

The Use of ex Vivo Rodent Platforms in Neuroscience Translational Research With Attention to the 3Rs Philosophy

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