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1.
Sci Rep ; 10(1): 10088, 2020 06 22.
Article in English | MEDLINE | ID: mdl-32572103

ABSTRACT

Ultrasound-induced blood-brain barrier (BBB) opening using microbubbles is a promising technique for local delivery of therapeutic molecules into the brain. The real-time control of the ultrasound dose delivered through the skull is necessary as the range of pressure for efficient and safe BBB opening is very narrow. Passive cavitation detection (PCD) is a method proposed to monitor the microbubble activity during ultrasound exposure. However, there is still no consensus on a reliable safety indicator able to predict potential damage in the brain. Current approaches for the control of the beam intensity based on PCD employ a full-pulse analysis and may suffer from a lack of sensitivity and poor reaction time. To overcome these limitations, we propose an intra-pulse analysis to monitor the evolution of the frequency content during ultrasound bursts. We hypothesized that the destabilization of microbubbles exposed to a critical level of ultrasound would result in the instantaneous generation of subharmonic and ultra-harmonic components. This specific signature was exploited to define a new sensitive indicator of the safety of the ultrasound protocol. The approach was validated in vivo in rats and non-human primates using a retrospective analysis. Our results demonstrate that intra-pulse monitoring was able to exhibit a sudden appearance of ultra-harmonics during the ultrasound excitation pulse. The repeated detection of such a signature within the excitation pulse was highly correlated with the occurrence of side effects such as hemorrhage and edema. Keeping the acoustic pressure at levels where no such sign of microbubble destabilization occurred resulted in safe BBB openings, as shown by MR images and gross pathology. This new indicator should be more sensitive than conventional full-pulse analysis and can be used to distinguish between potentially harmful and safe ultrasound conditions in the brain with very short reaction time.


Subject(s)
Blood-Brain Barrier/drug effects , Sonication/methods , Ultrasonic Therapy/methods , Acoustics , Animals , Brain/diagnostic imaging , Macaca fascicularis , Male , Microbubbles/therapeutic use , Primates , Rats , Rats, Sprague-Dawley , Retrospective Studies , Ultrasonography/methods
2.
Neurochirurgie ; 64(6): 422-424, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30477647

ABSTRACT

The discovery of the important role of cerebrospinal fluid (CSF) drainage of cerebral metabolite waste, known as the glymphatic system, has changed our view of brain waste clearance. We recently performed experiments to evaluate the glymphatic system in non-human primates (NHP). Here, we report the case of an NHP with iatrogenic CSF leakage. In this animal, solute transport through the brain, assessed by gadolinium injection in the CSF, was severely impaired by iatrogenic pseudomeningocele. This observation raises an important question: does brain surgery, and particularly posterior fossa surgery, lead to chronic impairment of parenchymal CSF circulation and solute transport?


Subject(s)
Brain/surgery , Cerebrospinal Fluid Rhinorrhea/etiology , Cerebrospinal Fluid/drug effects , Glymphatic System/surgery , Animals , Brain/metabolism , Cerebrospinal Fluid Rhinorrhea/surgery , Gadolinium/therapeutic use , Humans , Primates
3.
Sci Rep ; 8(1): 3362, 2018 02 20.
Article in English | MEDLINE | ID: mdl-29463867

ABSTRACT

Dissecting neural circuitry in non-human primates (NHP) is crucial to identify potential neuromodulation anatomical targets for the treatment of pharmacoresistant neuropsychiatric diseases by electrical neuromodulation. How targets of deep brain stimulation (DBS) and cortical targets of transcranial magnetic stimulation (TMS) compare and might complement one another is an important question. Combining optogenetics and tractography may enable anatomo-functional characterization of large brain cortico-subcortical neural pathways. For the proof-of-concept this approach was used in the NHP brain to characterize the motor cortico-subthalamic pathway (m_CSP) which might be involved in DBS action mechanism in Parkinson's disease (PD). Rabies-G-pseudotyped and Rabies-G-VSVg-pseudotyped EIAV lentiviral vectors encoding the opsin ChR2 gene were stereotaxically injected into the subthalamic nucleus (STN) and were retrogradely transported to the layer of the motor cortex projecting to STN. A precise anatomical mapping of this pathway was then performed using histology-guided high angular resolution MRI tractography guiding accurately cortical photostimulation of m_CSP origins. Photoexcitation of m_CSP axon terminals or m_CSP cortical origins modified the spikes distribution for photosensitive STN neurons firing rate in non-equivalent ways. Optogenetic tractography might help design preclinical neuromodulation studies in NHP models of neuropsychiatric disease choosing the most appropriate target for the tested hypothesis.


Subject(s)
Connectome , Nerve Net/anatomy & histology , Nerve Net/physiology , Optogenetics/methods , Action Potentials , Animals , Genes, Reporter , Genetic Vectors , Lentivirus/genetics , Macaca mulatta , Magnetic Resonance Imaging , Male , Motor Cortex/anatomy & histology , Motor Cortex/physiology , Opsins/analysis , Opsins/genetics , Subthalamic Nucleus/anatomy & histology , Subthalamic Nucleus/physiology , Transduction, Genetic
4.
Vet Pathol ; 54(2): 336-344, 2017 03.
Article in English | MEDLINE | ID: mdl-27694423

ABSTRACT

Posttransplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations that occur in the setting of depressed T-cell function due to immunosuppressive therapy used following solid organ transplantation, hematopoietic stem cell transplantation, and also xenotransplantation. In the present study, 28 immunosuppressed parkinsonian Macaca fascicularis were intracerebrally injected with wild-type or CTLA4-Ig transgenic porcine xenografts to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Nine of 28 (32%) immunosuppressed primates developed masses compatible with PTLD, located mainly in the gastrointestinal tract and/or nasal cavity. The masses were classified as monomorphic PTLD according to the World Health Organization classification. Immunohistochemistry and polymerase chain reaction (PCR) analyses revealed that the PTLDs were associated with macaca lymphocryptovirus as confirmed by double-labeling immunohistochemistry for CD20 and Epstein-Barr nuclear antigen 2 (EBNA-2), where the viral protein was located within the CD20+ neoplastic B cells. In sera from 3 distinct phases of the experimental life of the primates, testing by quantitative PCR revealed a progression of the viral load that paralleled the PTLD progression and no evidence of zoonotic transmission of porcine lymphotropic herpesvirus through xenoneuronal grafts. These data suggest that monitoring the variation of macaca lymphocryptovirus DNA in primates could be used as a possible early diagnostic tool for PTLD progression, allowing preemptive treatment such as immunosuppression therapy reduction.


Subject(s)
Lymphoproliferative Disorders/veterinary , Neural Stem Cells , Stem Cell Transplantation/adverse effects , Abatacept , Animals , Female , Immunocompromised Host , Lymphoproliferative Disorders/etiology , Lymphoproliferative Disorders/pathology , MPTP Poisoning , Macaca fascicularis , Male , Parkinson Disease, Secondary/chemically induced , Parkinson Disease, Secondary/therapy , Swine
5.
Am J Transplant ; 16(7): 2016-29, 2016 07.
Article in English | MEDLINE | ID: mdl-26749114

ABSTRACT

Neural transplantation is a promising therapeutic approach for neurodegenerative diseases; however, many patients receiving intracerebral fetal allografts exhibit signs of immunization to donor antigens that could compromise the graft. In this context, we intracerebrally transplanted mesencephalic pig xenografts into primates to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Parkinsonian primates received WT or CTLA4-Ig transgenic porcine xenografts and different durations of peripheral immunosuppression to test whether systemic plus graft-mediated local immunosuppression might avoid rejection. A striking recovery of spontaneous locomotion was observed in primates receiving systemic plus local immunosuppression for 6 mo. Recovery was associated with restoration of dopaminergic activity detected both by positron emission tomography imaging and histological examination. Local infiltration by T cells and CD80/86+ microglial cells expressing indoleamine 2,3-dioxigenase were observed only in CTLA4-Ig recipients. Results suggest that in this primate neurotransplantation model, peripheral immunosuppression is indispensable to achieve the long-term survival of porcine neuronal xenografts that is required to study the beneficial immunomodulatory effect of local blockade of T cell costimulation.


Subject(s)
CTLA-4 Antigen/immunology , Cell- and Tissue-Based Therapy/methods , Immunosuppression Therapy/methods , Neurons/cytology , Parkinson Disease/therapy , T-Lymphocytes/immunology , Animals , Animals, Genetically Modified , Cells, Cultured , Female , Graft Rejection/drug therapy , Graft Rejection/immunology , Graft Survival/drug effects , Graft Survival/immunology , Heterografts , Immunosuppressive Agents/therapeutic use , Lymphocyte Activation , Macaca fascicularis , Male , Neurons/immunology , Parkinson Disease/immunology , Sus scrofa , Transplantation, Heterologous
6.
Gene Ther ; 22(10): 830-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26109254

ABSTRACT

Cell-type-specific gene silencing is critical to understand cell functions in normal and pathological conditions, in particular in the brain where strong cellular heterogeneity exists. Molecular engineering of lentiviral vectors has been widely used to express genes of interest specifically in neurons or astrocytes. However, we show that these strategies are not suitable for astrocyte-specific gene silencing due to the processing of small hairpin RNA (shRNA) in a cell. Here we develop an indirect method based on a tetracycline-regulated system to fully restrict shRNA expression to astrocytes. The combination of Mokola-G envelope pseudotyping, glutamine synthetase promoter and two distinct microRNA target sequences provides a powerful tool for efficient and cell-type-specific gene silencing in the central nervous system. We anticipate our vector will be a potent and versatile system to improve the targeting of cell populations for fundamental as well as therapeutic applications.


Subject(s)
Astrocytes/physiology , Gene Transfer Techniques , Genetic Vectors , Lentivirus , RNA, Small Interfering , Animals , Central Nervous System/cytology , Central Nervous System/physiology , Gene Expression Regulation , Gene Silencing , Mice , Mice, Transgenic , Tetracycline
7.
Eur J Nucl Med Mol Imaging ; 42(3): 478-94, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25488184

ABSTRACT

PURPOSE: We aimed to characterize pharmacologically the TSPO- radioligand [(18)F]DPA-714 in the brain of healthy cynomolgus monkeys and evaluate the cellular origin of its binding in a model of neurodegeneration induced by intrastriatal injection of quinolinic acid (QA). METHODS: [(18)F]DPA-714 PET images were acquired before and at 2, 7, 14, 21, 49, 70, 91 days after putaminal lesioning. Blocking and displacement studies were carried out (PK11195). Different modelling approaches estimated rate constants and V T (total distribution volume) which was used to measure longitudinal changes in the lesioned putamen. Sections for immunohistochemical labelling were prepared at the same time-points to evaluate correlations between in vivo [(18)F]DPA-714 binding and microglial/astrocytic activation. RESULTS: [(18)F]DPA-714 showed a widespread distribution with a higher signal in the thalamus and occipital cortex and lower binding in the cerebellum. TSPO was expressed throughout the whole brain and about 73 % of [(18)F]DPA-714 binding was specific for TSPO in vivo. The one-tissue compartment model (1-TCM) provided good and reproducible estimates of V T and rate constants, and V T values from the 1-TCM and the Logan approach were highly correlated (r (2) = 0.85). QA lesioning induced an increase in V T, which was +17 %, +54 %, +157 % and +39 % higher than baseline on days 7, 14, 21 and 91 after QA injection, respectively. Immunohistochemistry revealed an early microglial and a delayed astrocytic activation after QA injection. [(18)F]DPA-714 binding matched TSPO immunopositive areas and showed a stronger colocalization with CD68 microglia than with GFAP-activated astrocytes. CONCLUSION: [(18)F]DPA-714 binds to TSPO with high specificity in the primate brain under normal conditions and in the QA model. This tracer provides a sensitive tool for assessing neuroinflammation in the human brain.


Subject(s)
Brain/diagnostic imaging , Positron-Emission Tomography , Pyrazoles/pharmacokinetics , Pyrimidines/pharmacokinetics , Radiopharmaceuticals/pharmacokinetics , Animals , Fluorine Radioisotopes/pharmacokinetics , Macaca fascicularis , Male , Receptors, GABA-A/metabolism , Tissue Distribution
8.
Transl Psychiatry ; 3: e253, 2013 Apr 30.
Article in English | MEDLINE | ID: mdl-23632457

ABSTRACT

The therapeutic activity of selective serotonin (5-HT) reuptake inhibitors (SSRIs) relies on long-term adaptation at pre- and post-synaptic levels. The sustained administration of SSRIs increases the serotonergic neurotransmission in response to a functional desensitization of the inhibitory 5-HT1A autoreceptor in the dorsal raphe. At nerve terminal such as the hippocampus, the enhancement of 5-HT availability increases brain-derived neurotrophic factor (BDNF) synthesis and signaling, a major event in the stimulation of adult neurogenesis. In physiological conditions, BDNF would be expressed at functionally relevant levels in neurons. However, the recent observation that SSRIs upregulate BDNF mRNA in primary cultures of astrocytes strongly suggest that the therapeutic activity of antidepressant drugs might result from an increase in BDNF synthesis in this cell type. In this study, by overexpressing BDNF in astrocytes, we balanced the ratio between astrocytic and neuronal BDNF raising the possibility that such manipulation could positively reverberate on anxiolytic-/antidepressant-like activities in transfected mice. Our results indicate that BDNF overexpression in hippocampal astrocytes produced anxiolytic-/antidepressant-like activity in the novelty suppressed feeding in relation with the stimulation of hippocampal neurogenesis whereas it did not potentiate the effects of the SSRI fluoxetine on these parameters. Moreover, overexpressing BDNF revealed the anxiolytic-like activity of fluoxetine in the elevated plus maze while attenuating 5-HT neurotransmission in response to a blunted downregulation of the 5-HT1A autoreceptor. These results emphasize an original role of hippocampal astrocytes in the synthesis of BDNF, which can act through neurogenesis-dependent and -independent mechanisms to regulate different facets of anxiolytic-like responses.


Subject(s)
Astrocytes/metabolism , Brain-Derived Neurotrophic Factor/metabolism , Hippocampus/metabolism , Neurogenesis/physiology , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Animals , Antidepressive Agents, Second-Generation/pharmacology , Anxiety/drug therapy , Anxiety/metabolism , Anxiety/physiopathology , Astrocytes/drug effects , Astrocytes/physiology , Behavior, Animal/drug effects , Behavior, Animal/physiology , Brain-Derived Neurotrophic Factor/analysis , Brain-Derived Neurotrophic Factor/physiology , Depression/drug therapy , Depression/metabolism , Depression/physiopathology , Fluoxetine/pharmacology , Gene Expression/physiology , Hippocampus/chemistry , Hippocampus/drug effects , Hippocampus/physiology , Male , Mice , Piperazines/pharmacology , Pyridines/pharmacology , Serotonin Antagonists/pharmacology , Serotonin Receptor Agonists/pharmacology
9.
Rev Neurol (Paris) ; 168(11): 802-5, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22981299

ABSTRACT

Huntington's disease (HD) is an inherited autosomal-dominant neurodegenerative disorder characterized by frontal-type cognitive deficits, involuntary choreiform movements and progressive neuronal degeneration, primarily affecting the caudate-putamen complex. There is currently no effective therapy for this disorder. Numerous efforts are directed towards the search and validation of new therapies to prevent or slow down disease progression. To this end, different animal models, including in nonhuman primates, have been developed to mimic the early phase of neuronal dysfunction that precedes degeneration in this pathology. The present manuscript provides a critical evaluation of existing and currently developed primate models of Huntington's disease. Their pertinence and predictability for the evaluation of innovative therapeutic strategies are also discussed.


Subject(s)
Disease Models, Animal , Huntington Disease/pathology , Primates , Prodromal Symptoms , Animals , Asymptomatic Diseases/therapy , Humans , Huntington Disease/therapy , Validation Studies as Topic
10.
Neuroimage ; 57(4): 1447-57, 2011 Aug 15.
Article in English | MEDLINE | ID: mdl-21571077

ABSTRACT

Murine models are commonly used in neuroscience research to improve our knowledge of disease processes and to test drug effects. To accurately study brain glucose metabolism in these animals, ex vivo autoradiography remains the gold standard. The analysis of 3D-reconstructed autoradiographic volumes using a voxel-wise approach allows clusters of voxels representing metabolic differences between groups to be revealed. However, the spatial localization of these clusters requires careful visual identification by a neuroanatomist, a time-consuming task that is often subject to misinterpretation. Moreover, the large number of voxels to be computed in autoradiographic rodent images leads to many false positives. Here, we proposed an original automated indexation of the results of a voxel-wise approach using an MRI-based 3D digital atlas, followed by the restriction of the statistical analysis using atlas-based segmentation, thus taking advantage of the specific and complementary strengths of these two approaches. In a preliminary study of transgenic Alzheimer's mice (APP/PS1), and control littermates (PS1), we were able to achieve prompt and direct anatomical indexation of metabolic changes detected between the two groups, revealing both hypo- and hypermetabolism in the brain of APP/PS1 mice. Furthermore, statistical results were refined using atlas-based segmentation: most interesting results were obtained for the hippocampus. We thus confirmed and extended our previous results by identifying the brain structures affected in this pathological model and demonstrating modified glucose uptake in structures like the olfactory bulb. Our combined approach thus paves the way for a complete and accurate examination of functional data from cerebral structures involved in models of neurodegenerative diseases.


Subject(s)
Alzheimer Disease/metabolism , Autoradiography/methods , Brain Mapping/methods , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Alzheimer Disease/pathology , Anatomy, Artistic , Animals , Atlases as Topic , Disease Models, Animal , Humans , Mice , Mice, Inbred C57BL , Mice, Transgenic
11.
Neuroimage ; 51(3): 1037-46, 2010 Jul 01.
Article in English | MEDLINE | ID: mdl-20226256

ABSTRACT

Murine models are commonly used in neuroscience to improve our knowledge of disease processes and to test drug effects. To accurately study neuroanatomy and brain function in small animals, histological staining and ex vivo autoradiography remain the gold standards to date. These analyses are classically performed by manually tracing regions of interest, which is time-consuming. For this reason, only a few 2D tissue sections are usually processed, resulting in a loss of information. We therefore proposed to match a 3D digital atlas with previously 3D-reconstructed post mortem data to automatically evaluate morphology and function in mouse brain structures. We used a freely available MRI-based 3D digital atlas derived from C57Bl/6J mouse brain scans (9.4T). The histological and autoradiographic volumes used were obtained from a preliminary study in APP(SL)/PS1(M146L) transgenic mice, models of Alzheimer's disease, and their control littermates (PS1(M146L)). We first deformed the original 3D MR images to match our experimental volumes. We then applied deformation parameters to warp the 3D digital atlas to match the data to be studied. The reliability of our method was qualitatively and quantitatively assessed by comparing atlas-based and manual segmentations in 3D. Our approach yields faster and more robust results than standard methods in the investigation of post mortem mouse data sets at the level of brain structures. It also constitutes an original method for the validation of an MRI-based atlas using histology and autoradiography as anatomical and functional references, respectively.


Subject(s)
Alzheimer Disease/pathology , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Models, Anatomic , Models, Neurological , Pattern Recognition, Automated/methods , Animals , Autoradiography/methods , Computer Simulation , Image Enhancement/methods , Mice , Mice, Inbred C57BL , Mice, Transgenic , Reproducibility of Results , Sensitivity and Specificity
12.
Neuroimage ; 32(4): 1562-75, 2006 Oct 01.
Article in English | MEDLINE | ID: mdl-16875847

ABSTRACT

The striatum, a subcortical structure, is the principal target of the neurodegenerative process in Huntington's disease (HD). The measurement of striatal atrophy using the bicaudate ratio on CT scanner images has therefore been used for years to assess disease progression, but this measure only takes into account unidimensional changes in the head of the caudate nucleus. Recently, voxel-based morphometry (VBM), which permits automated statistical comparisons of whole-brain MRI images, has been proposed to quantify striatal atrophy. However, VBM was not originally designed to study subcortical structures, and severe deep brain deformations that occur in HD may hamper the automatic processing of VBM. Here, we validate the use of the optimised protocol of VBM to quantify subcortical atrophy in HD by comparing results obtained with this method to those provided by manual segmentation of subcortical structures. We studied 20 patients with early HD and 12 controls matched for age, sex and handedness using an improved T1-weighted sequence that eased grey matter segmentation. Both manual and automated methods evidenced the dorso-ventral gradient of striatal atrophy, a loss of grey matter in the globus pallidus and the thalamus, and similar correlations between clinical scores and subcortical atrophy. Furthermore, we were able to detect with VBM grey matter loss in the substantia nigra, the hypothalamus, the amygdala, the insular cortex and the premotor and sensorimotor cortices. Finally, VBM provided results consistent with previous post mortem results and proved to be a sensitive biomarker capable of correctly managing subcortical distortions throughout HD patients' brains.


Subject(s)
Brain/pathology , Huntington Disease/pathology , Adult , Atrophy , Basal Ganglia/pathology , Basal Ganglia/physiopathology , Brain/physiopathology , Female , Globus Pallidus/pathology , Globus Pallidus/physiopathology , Humans , Huntington Disease/physiopathology , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Male , Middle Aged , Nonlinear Dynamics
13.
Neurobiol Aging ; 27(12): 1740-50, 2006 Dec.
Article in English | MEDLINE | ID: mdl-16337035

ABSTRACT

The amyloid precursor protein (APP) plays a central role in Alzheimer's disease (AD) pathogenesis through its cleavage leading to the accumulation of the peptide betaA4. Diffusible oligomeric assemblies of amyloid beta peptide are thought to induce synaptic dysfunction, an early change in AD. We tested the hypothesis that a reduction in presynaptic APP could itself lead to a decrease in synaptic efficacy in vivo. Twenty-four hours after intraocular injection, siRNA targeted against APP accumulated in retinal cells and the APP in retinal terminals in the superior colliculus was significantly reduced. Surprisingly, the amyloid precursor-like protein 2 (APLP2) was reduced as well. Functional imaging experiments in rats during visual stimulation showed that knockdown of presynaptic APP/APLP2 significantly reduced the stimulation-induced glucose utilization in the superior colliculus. Our results suggest that perturbations in the amount of APP/APLP2 axonally transported to, and/or in their turnover in the nerve terminal alter synaptic function and could be a pathogenic mechanism in AD.


Subject(s)
Amyloid beta-Protein Precursor/antagonists & inhibitors , Amyloid beta-Protein Precursor/genetics , Gene Targeting/methods , Neural Inhibition/genetics , RNA, Small Interfering/physiology , Synapses/genetics , Amyloid beta-Protein Precursor/biosynthesis , Animals , Axonal Transport/genetics , Male , Photic Stimulation/methods , Presynaptic Terminals/metabolism , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , RNA, Small Interfering/administration & dosage , Rats , Rats, Long-Evans , Retinal Ganglion Cells/metabolism , Synapses/metabolism
14.
J Gene Med ; 7(5): 530-9, 2005 May.
Article in English | MEDLINE | ID: mdl-15651039

ABSTRACT

The identification of disease-causing genes in familial forms of neurodegenerative disorders and the development of genetic models closely replicating human central nervous system (CNS) pathologies have drastically changed our understanding of the molecular events leading to neuronal cell death. If these achievements open new opportunities of therapeutic interventions, including gene-based therapies, the presence of the blood-brain barrier and the post-mitotic and poor regenerative nature of the target cells constitute important challenges. Efficient delivery systems taking into account the specificity of the CNS are required to administer potential therapeutic candidates. In addition, genetic models in large animals that replicate the late stages of the diseases are in most cases not available for pre-clinical studies. The present review summarizes the potential of viral vectors as tools to create new genetic models of CNS disorders in various species including primates and the recent progress toward viral gene therapy clinical trials for the administration of therapeutic candidates into the brain.


Subject(s)
Genetic Therapy , Genetic Vectors , Models, Biological , Neurodegenerative Diseases/therapy , Viruses/genetics , Blood-Brain Barrier/drug effects , Humans
15.
Hum Gene Ther ; 15(10): 968-75, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15585112

ABSTRACT

Huntington's disease (HD) is a monogenic neurodegenerative disease that affects the efferent neurons of the striatum. The protracted evolution of the pathology over 15 to 20 years, after clinical onset in adulthood, underscores the potential of therapeutic tools that would aim at protecting striatal neurons. Proteins with neuroprotective effects in the adult brain have been identified, among them ciliary neurotrophic factor (CNTF), which protected striatal neurons in animal models of HD. Accordingly, we have carried out a phase I study evaluating the safety of intracerebral administration of this protein in subjects with HD, using a device formed by a semipermeable membrane encapsulating a BHK cell line engineered to synthesize CNTF. Six subjects with stage 1 or 2 HD had one capsule implanted into the right lateral ventricle; the capsule was retrieved and exchanged for a new one every 6 months, over a total period of 2 years. No sign of CNTF-induced toxicity was observed; however, depression occurred in three subjects after removal of the last capsule, which may have correlated with the lack of any future therapeutic option. All retrieved capsules were intact but contained variable numbers of surviving cells, and CNTF release was low in 13 of 24 cases. Improvements in electrophysiological results were observed, and were correlated with capsules releasing the largest amount of CNTF. This phase I study shows the safety, feasibility, and tolerability of this gene therapy procedure. Heterogeneous cell survival, however, stresses the need for improving the technique.


Subject(s)
Genetic Therapy/methods , Huntington Disease/genetics , Huntington Disease/therapy , Neuroprotective Agents/pharmacology , Animals , Brain/metabolism , Cell Line , Cell Survival , Ciliary Neurotrophic Factor/chemistry , Ciliary Neurotrophic Factor/genetics , Codon , Cricetinae , Electrophysiology , Female , Gene Transfer Techniques , Humans , Male , Neurons/metabolism , Polymers/chemistry , Retroviridae/genetics , Time Factors
16.
Eur J Neurosci ; 16(12): 2351-7, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12492430

ABSTRACT

The morphogen sonic hedgehog (Shh) is implicated in neural tissue patterning and the growth of brain structures during embryogenesis and postnatal development and is also present in the adult brain. Shh signals through interaction with the tumour suppressor Patched (Ptc). This receptor for Shh is associated with Smoothened (Smo), a protein with high homology to the G-protein coupled receptors. However, little is known about the transduction mechanisms implicated in Shh signalling in the adult brain. The study described here shows that injection of aminoterminal myristoylated Shh (myrShhN) into the adult rat striatum robustly increases the levels of Ptc transcripts in selective brain areas including the subventricular zone (SVZ). The adult SVZ contains cell progenitors, which can proliferate and differentiate into new neurons and glia. In the myrShhN injected animals, proliferation and differentiation of these SVZ precursor cells were not affected as demonstrated by BrdU incorporation and immunohistochemistry performed with specific antibodies for nestin (uncommitted neural progenitors), PSA-NCAM (migrating neuroblasts) or GFAP (astrocytes). Together with the presence of Smo expressing cells and amino-terminal Shh (ShhN) protein in SVZ area of untreated animals, the data presented here supports the hypothesis that the Shh pathway may be activated in the adult brain, and that a niche for Shh signalling exists within the adult SVZ.


Subject(s)
Cell Differentiation/physiology , DNA-Binding Proteins , Membrane Proteins/metabolism , Neostriatum/growth & development , Neurons/metabolism , Receptors, G-Protein-Coupled , Stem Cells/metabolism , Trans-Activators/metabolism , Animals , Astrocytes/cytology , Astrocytes/drug effects , Astrocytes/metabolism , Basic Helix-Loop-Helix Transcription Factors , Cell Differentiation/drug effects , Cell Division/drug effects , Cell Division/physiology , Glial Fibrillary Acidic Protein/metabolism , Hedgehog Proteins , Immunohistochemistry , Intermediate Filament Proteins/metabolism , Lateral Ventricles/cytology , Lateral Ventricles/growth & development , Male , Membrane Proteins/drug effects , Myelin Proteolipid Protein/metabolism , Neostriatum/drug effects , Neostriatum/metabolism , Nerve Tissue Proteins/metabolism , Nestin , Neural Cell Adhesion Molecule L1/metabolism , Neurons/cytology , Neurons/drug effects , Oligodendroglia/cytology , Oligodendroglia/metabolism , Patched Receptors , Rats , Rats, Inbred Lew , Receptors, Cell Surface/drug effects , Receptors, Cell Surface/metabolism , Sialic Acids/metabolism , Signal Transduction/drug effects , Signal Transduction/physiology , Stem Cells/cytology , Stem Cells/drug effects , Trans-Activators/pharmacology
17.
Exp Neurol ; 172(1): 172-81, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11681849

ABSTRACT

Huntington's disease (HD) is generally considered a prototypic motor disorder, but cognitive deficits are also prominent features of the disease. Systemic administration of the mitochondrial toxin 3-nitropropionic acid (3NP) has been proposed to be a phenotypic model of HD in rats and nonhuman primates. In this study, we investigated the effect of 5 days continuous subcutaneous infusion of 3NP on motor and cognitive abilities in Lewis rats. Intoxicated animals developed a motor syndrome consisting of bradykinesia as well as gait abnormalities and dystonic hindlimbs. Results from learning tasks showed that these rats: (1) did not exhibit learning deficits per se in our discrimination task but showed impairments in inhibiting behavioral responses when a transfer of learning (to new stimuli) or a transfer of response (new position of the lever) was required; (2) showed a marked tendency to persevere in choosing the compartment they previously visited in a T maze, thus leading to a clear retardation in learning a reinforced alternation task; and (3) did not show any memory deficit when a delay was introduced. Six months later, histological analyses showed severe neurodegeneration within the lateral striatum accompanied by apparent cell loss in the ventral pallidum and entopedoncular nucleus. We suggest that the 3NP rat model of basal ganglia neurodegeneration may provide a useful model for studying certain fundamental aspects of the physiopathology of HD and for evaluating the functional efficacy of new therapeutic strategies.


Subject(s)
Attention/drug effects , Behavior, Animal/drug effects , Huntington Disease/physiopathology , Propionates/toxicity , Set, Psychology , Animals , Cognition/drug effects , Corpus Striatum/drug effects , Corpus Striatum/pathology , Discrimination Learning/drug effects , Disease Models, Animal , Drug Administration Schedule , Globus Pallidus/drug effects , Globus Pallidus/pathology , Huntington Disease/chemically induced , Huntington Disease/pathology , Injections, Subcutaneous , Male , Maze Learning/drug effects , Motor Activity/drug effects , Nitro Compounds , Propionates/administration & dosage , Rats , Rats, Inbred Lew , Transfer, Psychology/drug effects
18.
J Cereb Blood Flow Metab ; 21(7): 782-92, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11435790

ABSTRACT

Positron emission tomography (PET) coupled to 6-[18F]Fluoro-L-Dopa (18F-Dopa) remains the gold standard for assessing dysfunctionality concerning the dopaminergic nigrostriatal pathway in Parkinson's disease and related disorders. The use of ligands of the dopamine transporters (DAT) is an attractive alternative target; consequently, the current aim was to validate one of them, 11C-PE2I, using a multiinjection modeling approach allowing accurate quantitation of DAT densities in the striatum. Experiments were performed in three controls, three MPTP-treated (parkinsonian) baboons, and one reserpine-treated baboon. 11C-PE2I B'max values obtained with this approach were compared with 18F-Dopa input rate constant values (Ki), in vitro Bmax binding of 125I-PE2I, and the number of dopaminergic neurons in the substantia nigra estimated postmortem by stereology. In the caudate nucleus and putamen, control values for 11C-PE2I B'max were 673 and 658 pmol/mL, respectively, whereas it was strongly reduced in the MPTP-treated (B'max = 26 and 36 pmol/mL) and reserpine-treated animals (B'max = 338 and 483 pmol/mL). In vivo 11C-PE2I B'max values correlated with 18F-Dopa Ki values and in vitro 125I-PE2I Bmax values in the striatum and with the number of nigral dopaminergic neurons. Altogether, these data support the use of 11C-PE2I for monitoring striatal dopaminergic disorders and the effect of potential neuroprotective strategies.


Subject(s)
Brain/metabolism , Carrier Proteins/analysis , Dihydroxyphenylalanine/metabolism , Membrane Glycoproteins , Membrane Transport Proteins , Nerve Tissue Proteins , Nortropanes/metabolism , Parkinson Disease, Secondary/metabolism , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/administration & dosage , Animals , Brain Chemistry , Carbon Radioisotopes , Carrier Proteins/metabolism , Caudate Nucleus/chemistry , Caudate Nucleus/metabolism , Cerebellum/chemistry , Cerebellum/metabolism , Corpus Striatum/chemistry , Dihydroxyphenylalanine/analogs & derivatives , Dopamine Plasma Membrane Transport Proteins , Fluorine Radioisotopes , Kinetics , Ligands , Papio , Parkinson Disease, Secondary/chemically induced , Parkinson Disease, Secondary/pathology , Putamen/chemistry , Putamen/metabolism , Reserpine/administration & dosage , Substantia Nigra/chemistry , Substantia Nigra/metabolism , Tomography, Emission-Computed , Tyrosine 3-Monooxygenase/analysis
19.
Magn Reson Med ; 45(3): 517-20, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11241712

ABSTRACT

A new scheme is proposed to edit the 3.0 ppm GABA resonance without macromolecule (MM) contamination. Like previous difference spectroscopy approaches, the new scheme manipulates J-modulation of this signal using a selective editing pulse. The elimination of undesirable MM contribution at 3.0 ppm is obtained by applying this pulse symmetrically about the J-coupled MM resonance, at 1.7 ppm, in the two steps of the editing scheme. The effectiveness of the method is demonstrated in vitro, using lysine to mimic MM, and in vivo. As compared to the most commonly used editing scheme, which necessitates the acquisition and processing of two distinct difference spectroscopy experiments, the new scheme offers a reduction in experimental time (-33%) and an increase in accuracy. Magn Reson Med 45:517-520, 2001.


Subject(s)
Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging/methods , Magnetic Resonance Spectroscopy/methods , gamma-Aminobutyric Acid/metabolism , Animals , Artifacts , Humans , Imaging, Three-Dimensional , Macromolecular Substances , Papio , Phantoms, Imaging
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