scholarly journals Collagen hydrogels loaded with fibroblast growth factor-2 as a bridge to repair brain vessels in organotypic brain slices

2020 ◽  
Vol 238 (11) ◽  
pp. 2521-2529
Author(s):  
Buket Ucar ◽  
Sedef Yusufogullari ◽  
Christian Humpel
Keyword(s):  
Growth Factor ◽  
Brain Slice ◽  
Brain Slices ◽  
Vascular Endothelial ◽  
Brain Vessels ◽  
Collagen Hydrogel ◽  
Collagen Hydrogels ◽  
Organotypic Brain Slice ◽  
Set Up ◽  
Organotypic Brain Slices

Abstract Vessel damage is a general pathological process in many neurodegenerative disorders, as well as spinal cord injury, stroke, or trauma. Biomaterials can present novel tools to repair and regenerate damaged vessels. The aim of the present study is to test collagen hydrogels loaded with different angiogenic factors to study vessel repair in organotypic brain slice cultures. In the experimental set up I, we made a cut on the organotypic brain slice and tested re-growth of laminin + vessels. In the experimental set up II, we cultured two half brain slices with a gap with a collagen hydrogel placed in between to study endothelial cell migration. In the experimental set up I, we showed that the number of vessels crossing the cut was tendencially increased with the addition of fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor, or platelet-derived growth factor-BB compared to the control group. In the experimental set up II, we demonstrated that a collagen hydrogel loaded with FGF-2 resulted in a significantly increased number of migrated laminin + cells in the gap between the slices compared to the control hydrogel. Co-administration of several growth factors did not further potentiate the effects. Taken together, we show that organotypic brain slices are good models to study brain vessels and FGF-2 is a potent angiogenic factor for endothelial cell proliferation and migration. Our results provide evidence that the collagen hydrogels can be used as an extracellular matrix for the vascular endothelial cells.

Organotypic Brain Slices of ADULT Transgenic Mice: A Tool to Study Alzheimer’s Disease

2019 ◽  
Vol 16 (2) ◽  
pp. 172-181
Author(s):  
Christian Humpel
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transgenic Mice ◽  
Brain Slice ◽  
Ex Vivo ◽  
Brain Slices ◽  
Adult Mice ◽  
Organotypic Brain Slice ◽  
Brain Slice Cultures ◽  
Organotypic Brain Slices

Transgenic mice have been extensively used to study the Alzheimer pathology. In order to reduce, refine and replace (3Rs) the number of animals, ex vivo cultures are used and optimized. Organotypic brain slices are the most potent ex vivo slice culture models, keeping the 3-dimensional structure of the brain and being closest to the in vivo situation. Organotypic brain slice cultures have been used for many decades but were mainly prepared from postnatal (day 8-10) old rats or mice. More recent work (including our lab) now aims to culture organotypic brain slices from adult mice including transgenic mice. Especially in Alzheimer´s disease research, brain slices from adult transgenic mice will be useful to study beta-amyloid plaques, tau pathology and glial activation. This review will summarize the studies using organotypic brain slice cultures from adult mice to mimic Alzheimer's disease and will highlight advantages and also pitfalls using this technique.

scholarly journals Spreading of Beta-Amyloid in Organotypic Mouse Brain Slices and Microglial Elimination and Effects on Cholinergic Neurons

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 434
Author(s):  
Kurt Moelgg ◽  
Faryal Jummun ◽  
Christian Humpel
Keyword(s):  
Ventral Striatum ◽  
Brain Slices ◽  
Cholinergic Neurons ◽  
Brain Areas ◽  
Aβ Peptides ◽  
Collagen Hydrogels ◽  
Amyloid Aβ ◽  
Glial Reactions ◽  
Over Time ◽  
Organotypic Brain Slices

The extracellular deposition of b-amyloid (Aβ) is one of the major characteristics in Alzheimer´s disease (AD). The”spreading hypothesis” suggests that a pathological protein (similar to prions) spreads over the entire brain. The aim of the present study was to use organotypic brain slices of postnatal day 8–10 mice. Using collagen hydrogels, we applied different Aβ peptides onto brain slices and analyzed spreading as well as glial reactions after eight weeks of incubation. Our data showed that from all tested Aβ peptides, human Aβ42 had the most potent activity to spread over into adjacent”target“ areas. This effect was potentiated when brain slices from transgenic AD mice (APP_SweDI) were cultured. When different brain areas were connected to the”target slice“ the spreading activity was more intense, originating from ventral striatum and brain stem. Reactive glial-fibrillary acidic protein (GFAP) astrogliosis increased over time, but Aβ depositions co-localized only with Iba1+ microglia but not with astrocytes. Application of human Aβ42 did not cause a degeneration of cholinergic neurons. We concluded that human Aβ42 spreads over into other”target areas“, causing activation of glial cells. Most of the spread Aβ42 was taken up by microglia, and thus toxic free Aβ could not damage cholinergic neurons.

Abstract 300: A Novel Targeted Angiogenesis Technique Using Magnetic Nanoparticles

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Mark Arokiaraj
Keyword(s):  
Magnetic Nanoparticles ◽  
Growth Factor ◽  
Confocal Microscopy ◽  
Cell Monolayer ◽  
Basal Layer ◽  
Vascular Endothelial ◽  
Microfluidic Chips ◽  
Collagen Hydrogel ◽  
Huvec Cell ◽  
Endothelial Growth Factor

Aims: To develop a novel technique for angiogenesis which could be potentially useful for therapeutic purposes using magnetic nanoparticles. Methods: Magnetic nanoparticles were synthesized and were conjugated with vascular endothelial growth factor. The particles were tested in tissue culture microfluidic chips for angiogenesis. Four layers were generated for the experiment respectively - the nutrient layer, hydrogel layer, HUVEC spheroids and another hydrogel layer in the bottom. The particles were inserted in a layer of collagen hydrogel and were guided to desired location using a magnet. The extent and the direction of angiogenesis were studied using 3D confocal microscopy. Results: Angiogenesis was observed compared to the controls when nanoparticles were interfaced between the nutrient and HUVEC layer. When the nanoparticles was placed below the HUVEC spheroids angiogenesis occurred in the basal layer predominantly, which showed the effect of the nanoparticles with growth factor on angiogenesis more than the nutrients. In another experiment in microfluidic chip, the nanoparticles were placed in nutrient layer and HUVEC cell monolayer was placed underneath the nutrient layer. The nanoparticles was observed to cross endothelial cells and reach lower hydrogel layer, which was observed by Z stack confocal microscopy. Conclusion: Angiogenesis happen by the effect of magnetic nanoparticles conjugated with growth factors. These nanoparticles can be controlled with a magnet. Also, these nanoparticles have potentials to cross endothelium.

The Organic Cation Transporter 2 Inhibitor Quinidine Modulates the Neuroprotective Effect of Nerve Growth Factor and Memantine on Cholinergic Neurons of the Basal Nucleus of Meynert in Organotypic Brain Slices

Pharmacology ◽  
2021 ◽  
pp. 1-10
Author(s):  
Tugba Gulsun ◽  
Buket Ucar ◽  
Selma Sahin ◽  
Christian Humpel
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Organic Cation ◽  
Brain Slices ◽  
Cholinergic Neurons ◽  
Organic Cation Transporter ◽  
Nerve Growth ◽  
Organic Cation Transporter 2 ◽  
The Brain ◽  
Organotypic Brain Slices

<b><i>Introduction:</i></b> Alzheimer’s disease (AD) is a severe neurodegenerative disorder of the brain characterized by degeneration of cholinergic neurons which is directly linked to cognitive decline. Nerve growth factor (NGF) is the most potent protective factor for cholinergic neurons, additionally the NMDA antagonist memantine blocks glutamate-mediated excitotoxic activity. Quinidine is an inhibitor of organic cation transporter 2 (OCT2). OCT2 is located on cholinergic neurons and plays a role in presynaptic reuptake and recycling of acetylcholine in the brain. We hypothesize that quinidine can modulate the protective effects of NGF and memantine on cholinergic neurons in organotypic brain slices of the nucleus basalis of Meynert (nBM). <b><i>Methods:</i></b> Organotypic brain slices of nBM were incubated with 100 ng/mL NGF, 10 µM memantine, 10 µM quinidine, and combinations of these treatments for 2 weeks. Cholinergic neurons were immunohistochemically stained for choline acetyltransferase (ChAT). <b><i>Results:</i></b> Our data show that NGF as well as memantine counteracted the cell death of cholinergic nBM neurons. Quinidine alone had no toxic effect on cholinergic neurons but inhibited the protective effect of NGF and memantine when applied simultaneously. <b><i>Discussion/Conclusion:</i></b> Our data provide evidence that quinidine modulates the survival of cholinergic nBM neurons via OCT2.

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