Microelectrode arrays (MEA) for measuring spatio-temporal neural activity generated by low-energy focused ultrasound (LEFUS) in ex vivo brain slices

2019 ◽  
Vol 146 (4) ◽  
pp. 3030-3030
Author(s):  
Ivan M. Suarez Castellanos ◽  
Apoutou N'Djin ◽  
Jérémy Vion-Bailly ◽  
Elena Dossi ◽  
Alexandre Carpentier ◽  
...  
Keyword(s):  
Neural Activity ◽  
Focused Ultrasound ◽  
Ex Vivo ◽  
Brain Slices ◽  
Microelectrode Arrays ◽  
Low Energy ◽  
Spatio Temporal

scholarly journals Mild hyperthermia by MR-guided focused ultrasound in an ex vivo model of osteolytic bone tumour: optimization of the spatio-temporal control of the delivered temperature

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Pauline C. Guillemin ◽  
Laura Gui ◽  
Orane Lorton ◽  
Thomas Zilli ◽  
Lindsey A. Crowe ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Focused Ultrasound ◽  
Focal Spot ◽  
Ex Vivo ◽  
External Beam Radiation ◽  
Bone Tumours ◽  
Mr Thermometry ◽  
Beam Radiation ◽  
Mild Hyperthermia ◽  
Spatio Temporal

Abstract Background Magnetic resonance guided focused ultrasound was suggested for the induction of deep localized hyperthermia adjuvant to radiation- or chemotherapy. In this study we are aiming to validate an experimental model for the induction of uniform temperature elevation in osteolytic bone tumours, using the natural acoustic window provided by the cortical breakthrough. Materials and methods Experiments were conducted on ex vivo lamb shank by mimicking osteolytic bone tumours. The cortical breakthrough was exploited to induce hyperthermia inside the medullar cavity by delivering acoustic energy from a phased array HIFU transducer. MR thermometry data was acquired intra-operatory using the proton resonance frequency shift (PRFS) method. Active temperature control was achieved via a closed-loop predictive controller set at 6 °C above the baseline. Several beam geometries with respect to the cortical breakthrough were investigated. Numerical simulations were used to further explain the observed phenomena. Thermal safety of bone heating was assessed by cross-correlating MR thermometry data with the measurements from a fluoroptic temperature sensor inserted in the cortical bone. Results Numerical simulations and MR thermometry confirmed the feasibility of spatio-temporal uniform hyperthermia (± 0.5 °C) inside the medullar cavity using a fixed focal point sonication. This result was obtained by the combination of several factors: an optimal positioning of the focal spot in the plane of the cortical breakthrough, the direct absorption of the HIFU beam at the focal spot, the “acoustic oven effect” yielded by the beam interaction with the bone, and a predictive temperature controller. The fluoroptical sensor data revealed no heating risks for the bone and adjacent tissues and were in good agreement with the PRFS thermometry from measurable voxels adjacent to the periosteum. Conclusion To our knowledge, this is the first study demonstrating the feasibility of MR-guided focused ultrasound hyperthermia inside the medullar cavity of bones affected by osteolytic tumours. Our results are considered a promising step for combining adjuvant mild hyperthermia to external beam radiation therapy for sustained pain relief in patients with symptomatic bone metastases.

scholarly journals Characterization and Ex Vivo evaluation of an extracorporeal high‐intensity focused ultrasound (HIFU) system

2021 ◽  
Author(s):  
Yufeng Zhou ◽  
Bryan W. Cunitz ◽  
Barbrina Dunmire ◽  
Yak‐Nam Wang ◽  
Steven G. Karl ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Ex Vivo ◽  
High Intensity Focused Ultrasound

scholarly journals TAMI-28. DIFFERENTIAL MIGRATION MECHANICS AND IMMUNE RESPONSES OF GLIOMA SUBTYPES

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii219-ii219
Author(s):  
Ghaidan Shamsan ◽  
Chao Liu ◽  
Brooke Braman ◽  
Susan Rathe ◽  
Aaron Sarver ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Immune Cell ◽  
Molecular Subtypes ◽  
Ex Vivo ◽  
Brain Slices ◽  
Traction Force ◽  
Genetic Alterations ◽  
Sleeping Beauty ◽  
Brain Parenchyma ◽  
Biophysical Modeling

Abstract In Glioblastoma (GBM), tumor spreading is driven by tumor cells’ ability to infiltrate healthy brain parenchyma, which prevents complete surgical resection and contributes to tumor recurrence. GBM molecular subtypes, classical, proneural and mesenchymal, were shown to strongly correlate with specific genetic alterations (Mesenchymal: NF1; Classical: EGFRVIII; Proneural: PDGFRA). Here we tested the hypothesis that a key mechanistic difference between GBM molecular subtypes is that proneural cells are slow migrating and mesenchymal cells are fast migrating. Using Sleeping Beauty transposon system, immune-competent murine brain tumors were induced by SV40-LgT antigen in combination with either NRASG12V (NRAS) or PDGFB (PDGF) overexpression. Cross-species transcriptomic analysis revealed NRAS and PDGF-driven tumors correlate with human mesenchymal and proneural GBM, respectively. Similar to human GBM, CD44 expression was higher in NRAS tumors and, consistent with migration simulations of varying CD44 levels, ex vivo brain slice live imaging showed NRAS tumors cells migrate faster than PDGF tumors cells (random motility coefficient = 30µm2/hr vs. 2.5µm2/hr, p < 0.001). Consistent with CD44 function as an adhesion molecule, migration phenotype was independent of the tumor microenvironment. NRAS and human PDX/MES tumor cells were found to migrate faster and have larger cell spread area than PDGF and human PDX/PN tumors cells, respectively, in healthy mouse brain slices. Furthermore, traction force microscopy revealed NRAS tumor cells generate larger traction forces than PDGF tumors cells which further supports our theoretical mechanism driving glioma migration. Despite increased migration, NRAS cohort had better survival than PDGF which was attributed to enhanced antitumoral immune response in NRAS tumors, consistent with increased immune cell infiltration found in human mesenchymal GBM. Overall our work identified a potentially actionable difference in migration mechanics between GBM subtypes and establishes an integrated biophysical modeling and experimental approach to mechanically parameterize and simulate distinct molecular subtypes in preclinical models of cancer.

scholarly journals Quantitative measurement of reactive oxygen species in ex vivo mouse brain slices

2021 ◽  
Vol 2 (1) ◽  
pp. 100332
Author(s):  
Chirag Vasavda ◽  
Solomon H. Snyder ◽  
Bindu D. Paul
Keyword(s):  
Reactive Oxygen Species ◽  
Mouse Brain ◽  
Quantitative Measurement ◽  
Ex Vivo ◽  
Brain Slices ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals A New Transgenic Mouse Line for Imaging Mitochondrial Calcium Signals

Function ◽  
2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Nelly Redolfi ◽  
Elisa Greotti ◽  
Giulia Zanetti ◽  
Tino Hochepied ◽  
Cristina Fasolato ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Fluorescent Protein ◽  
Ex Vivo ◽  
Brain Slices ◽  
Resonance Energy ◽  
Mouse Line ◽  
Isolated Cells ◽  
Genomic Locus ◽  
Transgenic Mouse Line

AbstractMitochondria play a key role in cellular calcium (Ca2+) homeostasis. Dysfunction in the organelle Ca2+ handling appears to be involved in several pathological conditions, ranging from neurodegenerative diseases, cardiac failure and malignant transformation. In the past years, several targeted green fluorescent protein (GFP)-based genetically encoded Ca2+ indicators (GECIs) have been developed to study Ca2+ dynamics inside mitochondria of living cells. Surprisingly, while there is a number of transgenic mice expressing different types of cytosolic GECIs, few examples are available expressing mitochondria-localized GECIs, and none of them exhibits adequate spatial resolution. Here we report the generation and characterization of a transgenic mouse line (hereafter called mt-Cam) for the controlled expression of a mitochondria-targeted, Förster resonance energy transfer (FRET)-based Cameleon, 4mtD3cpv. To achieve this goal, we engineered the mouse ROSA26 genomic locus by inserting the optimized sequence of 4mtD3cpv, preceded by a loxP-STOP-loxP sequence. The probe can be readily expressed in a tissue-specific manner upon Cre recombinase-mediated excision, obtainable with a single cross. Upon ubiquitous Cre expression, the Cameleon is specifically localized in the mitochondrial matrix of cells in all the organs and tissues analyzed, from embryos to aged animals. Ca2+ imaging experiments performed in vitro and ex vivo in brain slices confirmed the functionality of the probe in isolated cells and live tissues. This new transgenic mouse line allows the study of mitochondrial Ca2+ dynamics in different tissues with no invasive intervention (such as viral infection or electroporation), potentially allowing simple calibration of the fluorescent signals in terms of mitochondrial Ca2+ concentration ([Ca2+]).

scholarly journals Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 898
Author(s):  
Brian H. Kim ◽  
Maciej Jeziorek ◽  
Hur Dolunay Kanal ◽  
Viorica Raluca Contu ◽  
Radek Dobrowolski ◽  
...  
Keyword(s):  
Cell Death ◽  
Structural Integrity ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Brain Slices ◽  
Brain Structures ◽  
Improved Outcomes ◽  
Hypoxia Ischemia ◽  
Tgfβ Receptor ◽  
Progressive Neurodegeneration

Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly elevated following HI and that delivering an antagonist for TGFβ receptor activin-like kinase 5 (ALK5)—SB505124—three days after injury in a rat model of moderate pre-term HI significantly preserved the structural integrity of the thalamus and hippocampus as well as neurological functions associated with those brain structures. To elucidate the mechanism whereby ALK5 inhibition reduces cell death, we assessed levels of autophagy markers in neurons and found that SB505124 increased numbers of autophagosomes and levels of lipidated light chain 3 (LC3), a key protein known to mediate autophagy. However, those studies did not determine whether (1) SB was acting directly on the CNS and (2) whether directly inducing autophagy could decrease cell death and improve outcome. Here we show that administering an ALK5 antagonist three days after HI reduced actively apoptotic cells by ~90% when assessed one week after injury. Ex vivo studies using the lysosomal inhibitor chloroquine confirmed that SB505124 enhanced autophagy flux in the injured hemisphere, with a significant accumulation of the autophagic proteins LC3 and p62 in SB505124 + chloroquine treated brain slices. We independently activated autophagy using the stimulatory peptide Tat-Beclin1 to determine if enhanced autophagy is directly responsible for improved outcomes. Administering Tat-Beclin1 starting three days after injury preserved the structural integrity of the hippocampus and thalamus with improved sensorimotor function. These data support the conclusion that intervening at this phase of injury represents a window of opportunity where stimulating autophagy is beneficial.

scholarly journals Trans-cranial focused ultrasound without hair shaving: feasibility study in an ex vivo cadaver model

2013 ◽  
Vol 1 (1) ◽  
pp. 24 ◽  
Author(s):  
Matthew DC Eames ◽  
Arik Hananel ◽  
John W Snell ◽  
Neal F Kassell ◽  
Jean-Francois Aubry
Keyword(s):  
Feasibility Study ◽  
Focused Ultrasound ◽  
Ex Vivo

scholarly journals Multicellular ‘hotspots’ harbour high-grade potential in lower-grade gliomas

2021 ◽  
Author(s):  
Alastair J Kirby ◽  
José P Lavrador ◽  
Istvan Bodi ◽  
Francesco Vergani ◽  
Ranjeev Bhangoo ◽  
...  
Keyword(s):  
Human Brain ◽  
Brain Tissue ◽  
Aminolevulinic Acid ◽  
Ex Vivo ◽  
Brain Slices ◽  
Glioma Cells ◽  
Malignant Progression ◽  
Lower Grade ◽  
High Grade ◽  
Human Brain Tissue

Abstract Background Lower-grade gliomas may be indolent for many years before developing malignant behaviour. The reasons mechanisms underlying malignant progression remain unclear. Methods We collected blocks of live human brain tissue donated by people undergoing glioma resection. The tissue blocks extended through the peritumoral cortex and into the glioma. The living human brain tissue was cut into ex vivo brain slices and bathed in 5-aminolevulinic acid (5-ALA). High-grade glioma cells avidly take up 5-aminolevulinic acid (5-ALA) and accumulate high levels of the fluorescent metabolite, Protoporphyrin IX (PpIX). We exploited the PpIX fluorescence emitted by higher-grade glioma cells to investigate the earliest stages of malignant progression in lower-grade gliomas. Results We found sparsely-distributed ‘hot-spots’ of PpIX-positive cells in living lower-grade glioma tissue. Glioma cells and endothelial cells formed part of the PpIX hotspots. Glioma cells in PpIX hotspots were IDH1 mutant and expressed nestin suggesting they had acquired stem-like properties. Spatial analysis with 5-ALA conjugated quantum dots indicated that these glioma cells replicated adjacent to blood vessels. PpIX hotspots formed in the absence of angiogenesis. Conclusion Our data show that PpIX hotspots represent microdomains of cells with high-grade potential within lower-grade gliomas and identify locations where malignant progression could start.

Sign in / Sign up

Export Citation Format

Share Document