Nous remercions sincèrement F. Bierry pour l&#39;aide à la production et le montage vidéo.

Toutes les procédures impliquant des sujets animaux ont été approuvés par le comité d&#39;Institutional Animal Care Centre Hospitalier Universitaire. 1. L&#39;inoculation bactérienne intra-articulaire <ol><li> Avant l&#39;injection, anesthésier lapins par injection intramusculaire de kétamine (30 mg / kg de poids corporel) mélangé avec de la xylazine (4 mg / kg) dans les muscles spinaux. S&#39;assurer que les animaux sont complètement anesthésiés en vérifiant qu&#39;ils ne parviennent pas à répondre aux pincée de patte. Ce protocole permet l&#39;anesthésie suffisante pour l&#39;injection intra-articulaire de l&#39;articulation du genou. Placez les animaux sous masque à oxygène pendant l&#39;anesthésie. </li><li> Raser le genou animaux. Préparation du genou pour une injection aseptique par trois lingettes alternées de gommage povidone-iode et de l&#39;alcool suivie de l&#39;application d&#39;une solution de povidone-iode. </li><li> Identifier manuellement le tendon rotulien comme une structure élastique à la face antérieure du genou à l&#39;aide d&#39;un capuchon d&#39;aiguille stérile comme indiqué ou une sonde stérile. </li><li&gt; Avec un contrôle visuel et en utilisant une approche antérieure, placez une aiguille de calibre 25 par voie percutanée dans le genou droit de chacun des 12 lapins à travers le tendon rotulien. </li><li> Injecter chaque genou avec 1 ml d&#39;une suspension bactérienne de Staphylococcus aureus (souche Neumann) à une concentration de 10 6 UFC / ml. Une injection sans résistance confirme la localisation intra-articulaire de la pointe de l&#39;aiguille. </li><li> Après les procédures d&#39;injection, garder l&#39;animal en vertu source de convection pour éviter les pertes de chaleur et de suivre le rythme respiratoire en observant le mouvement de la poitrine. Une fois réveillé, garder les animaux dans des cages avec un accès libre à la nourriture et à l&#39;eau. </li><li> Gérer la douleur par administration d&#39;une injection intramusculaire de 0,1 mg / kg toutes les 8 heures buprénorphine. </li><li> Cliniquement observer les lapins chaque jour, contrôle des quantités consommées de nourriture et d&#39;eau, perte de poids, la température et le comportement général. </li><li> Pour l&#39;image de la phase aiguë de l&#39;infection à effectuer la première séance d&#39;imagerie RM dèscomme un animal présente une perte de poids importante (10%), généralement cela se produit après environ 2 jours. </li><li> Si l&#39;administration de drogues par voie intraveineuse est nécessaire avant l&#39;examen IRM, un accès veineux auriculaire peut être installé (cf. ci-dessous). </li></ol> 2. L&#39;examen IRM Quand l&#39;imagerie des animaux vivants, une installation animal attention est un élément clé pour assurer le confort des animaux et de l&#39;anesthésie optimale. Cela permettra d&#39;obtenir de meilleurs résultats d&#39;imagerie et d&#39;assurer une acquisition d&#39;image de reproduction pour les études longitudinales. En raison de la taille de l&#39;animal, l&#39;utilisation d&#39;une unité MR clinique taille (1,5 T ou 3 T) est le plus approprié. Bobine de genou clinique 8 canaux est utilisée car elle offre la résolution appropriée et le rapport contraste sur bruit pour le lapin exploration du genou. <ol><li> Avant l&#39;installation du système d&#39;imagerie, installer un accès veineux périphérique à travers une veine auriculaire. Cet accès permettra d&#39;injecter l&#39;agent de contraste. <ol><li> Rasage et désinfecter l&#39;oreille. </li><li&gt; Perform anesthésie locale par injection sous-cutanée de lidocaïne. </li><li> Insérer un cathéter 25 G à l&#39;intérieur de la veine auriculaire latérale. </li><li> Évaluer la perméabilité par injection de 1 ml de sérum physiologique stérile. </li><li> Maintenir le cathéter avec taraudage adhésif. </li></ol></li><li> Anesthésier des animaux au moyen d&#39;une injection intramusculaire de kétamine (30 mg / kg de poids corporel) mélangé avec la xylazine (4 mg / kg). Les animaux sont entièrement anesthésié une fois qu&#39;ils ne parviennent pas à répondre aux pincée de patte. Placer un masque facial sur le lapin, en lui donnant l&#39;oxygène avec un débit de 200 ml / min. </li><li> Une fois complètement anesthésié, prendre l&#39;animal à l&#39;unité IRM. Placer les animaux de manière que les genoux sont situés dans le centre de la bobine MR. Placer les pattes de l&#39;animal en extension complète, de sorte que le grand axe du tibia est parallèle à la table d&#39;unités d&#39;imagerie MR. Utilisez des attaches velcro ou des sacs de sable pour maintenir la position optimale de la jambe. </li><li> Surveillance cardio-respiratoire des animaux n&#39;est pas nécessaire que l&#39;protocole d&#39;anesthésie permet une anesthésie profonde sur la respiration spontanée, mais les animaux doivent être couverts pour éviter la perte de chaleur induite par l&#39;anesthésie. </li><li> M. protocole est détaillé dans le tableau 1. Le délai moyen d&#39;acquisition total, y compris une installation optimale est d&#39;environ 20 min. </li><li> Effectuez l&#39;IRM dans des plans différents. Néanmoins, le plan transversal des genoux (orthogonal au tibia) est le plan de référence car elle garantit la reproductibilité anatomique de la position de l&#39;image pour des examens longitudinaux successifs et permet corrélation optimale avec des tranches histologiques. </li><li> À la fin de séquences non améliorées, injecter le produit de contraste UPSIO grâce à l&#39;accès veineux auriculaire. Lentement administrer des particules d&#39;oxyde de fer en une seule dose de 150 pmol de Fe / kg. Rincer le cathéter par injection de 1 ml de sérum physiologique stérile. </li><li> Répétez la séquence pondérée améliorée GRE 24 heures après l&#39;injection. Ce délai permet aux particules d&#39;être phagocytées parles macrophages. </li><li> Pour les études longitudinales évaluant l&#39;effet de médicaments (antibiotiques, des stéroïdes, des anticorps anti-macrophages, etc.), Répéter les examens IRM séquentielles selon le protocole décrit ci-dessus. </li></ol> 3. Analyse d&#39;Image <ol><li> Pour l&#39;évaluation longitudinale effectuer des mesures au même niveau anatomique, et de définir un point de repère facilement identifiable. Par exemple, l&#39;acquisition par le plan axial où l&#39;on observe le plus grand diamètre de la rotule est un moyen fiable pour obtenir des mesures reproductibles (figure 1). </li><li> Procéder à l&#39;analyse d&#39;image en utilisant un logiciel DICOM basée (comme Osirix) ou un logiciel de traitement d&#39;image (ImageJ). </li><li> En utilisant le logiciel ImageJ, effectuer la segmentation de l&#39;espace synovial qui démontre la perte de signal sur USPIO-image améliorée GRE pondérée en T2 en utilisant l&#39;outil de dessin «irrégulière de la zone&quot;. Une fois la membrane synoviale avec signal d&#39;obscurité est décrit, cliquez sur &quot;Analyser&quot; pour obtenir la région /nombre de pixels (figure 2). </li></ol>

<ol>
	<li>Madri, J., Kissane, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflammation+and+healing.">Inflammation and healing.</a> Anderson's Pathology. , 67-110 (1990).</li><li>Sephel, G., Woodward, S., Rubin, R., Strayer, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repair,+regeneration,+and+fibrosis.">Repair, regeneration, and fibrosis.</a> Rubin's Pathology. , 71-98 (2008).</li><li>Verdrengh, M., Tarkowski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+macrophages+in+Staphylococcus+aureus-induced+arthritis+and+sepsis.">Role of macrophages in Staphylococcus aureus-induced arthritis and sepsis.</a> Arthritis Rheum. 43 (10), 2276-2282 (2000).</li><li>Heale, J., Speert, D., Burke, B., Lewis, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages+in+bacterial+infection.">Macrophages in bacterial infection.</a> The Macrophage. , 210-252 (2008).</li><li>Bierry, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage+activity+in+infected+areas+of+an+experimental+vertebral+osteomyelitis+model:+USPIO-enhanced+MR+imaging--feasibility+study.">Macrophage activity in infected areas of an experimental vertebral osteomyelitis model: USPIO-enhanced MR imaging--feasibility study.</a> Radiology. 248 (1), 114-123 (2008).</li><li>Bierry, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MRI+of+macrophages+in+infectious+knee+synovitis.">MRI of macrophages in infectious knee synovitis.</a> AJR Am. J. Roentgenol. 194 (6), W521-W526 (2010).</li><li>Lutz, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+synovial+macrophages+in+an+experimental+rabbit+model+of+antigen-induced+arthritis:+ultrasmall+superparamagnetic+iron+oxide-enhanced+MR+imaging.">Detection of synovial macrophages in an experimental rabbit model of antigen-induced arthritis: ultrasmall superparamagnetic iron oxide-enhanced MR imaging.</a> Radiology. 233 (1), 149-1457 (2004).</li><li>Weissleder, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasmall+superparamagnetic+iron+oxide:+an+intravenous+contrast+agent+for+assessing+lymph+nodes+with+MR+imaging.">Ultrasmall superparamagnetic iron oxide: an intravenous contrast agent for assessing lymph nodes with MR imaging.</a> Radiology. 175 (2), 494-498 (1990).</li><li>Lefevre, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Septic+arthritis:+monitoring+with+USPIO-enhanced+macrophage+MR+imaging.">Septic arthritis: monitoring with USPIO-enhanced macrophage MR imaging.</a> Radiology. 258 (3), 722-728 (2011).</li><li>Sigovan, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid-clearance+iron+nanoparticles+for+inflammation+imaging+of+atherosclerotic+plaque:+initial+experience+in+animal+model.">Rapid-clearance iron nanoparticles for inflammation imaging of atherosclerotic plaque: initial experience in animal model.</a> Radiology. 252 (2), 401-409 (2009).</li></ol>

Les auteurs n&#39;ont rien à révéler.

Alors que les agents de contraste à base de gadolinium non spécifiques fournissent des informations sur le volume et la perfusion de l&#39;espace extracellulaire, l&#39;imagerie macrophage par USPIO-enhanced MR permet une localisation anatomique précise et une évaluation qualitative de l&#39;infiltration macrophagique au sein de la synoviale infecté sans avoir besoin de prélèvement de tissu 9. En raison de leur grande sensibilité, USPIO peut démontrer, même subtile infiltrat cellulaire présent dans...

L&#39;imagerie par résonance magnétique (IRM) est considéré comme la modalité d&#39;imagerie de choix pour la manifestation de la synovite infectieuse due à sa haute résolution spatiale et le contraste des tissus mous. changements de signaux observés à l&#39;IRM dans l&#39;arthrite faible T1 et un signal élevé T2 reflète la présence accrue de la teneur en eau extracellulaire et une amélioration marquée après l&#39;administration de l&#39;agent à base de gadolinium, en conformité avec les histologiquement conclusions d&#39;augmentation de la vascularisation en raison de la vasodilatation et l&#39;angiogenèse 1. Néanmoins, l&#39;IRM est souvent incapable de démontrer la résolution de l&#39;infection pendant le traitement antibiotique que l&#39;amélioration persistante peut être observé dans les articulations des patients atteints d&#39;arthrite septique cliniquement et biologiquement guéri en raison de la persistance de l&#39;espace extracellulaire agrandie (tissu de granulation, cicatrice fibreuse) 2. Outre les changements extracellulaires, les cellules inflammatoires, notamment un recrutement intense de macrophages infiltrent massivement dans l&#39;infectés synovie. Les macrophages jouent un rôle majeur à la fois dans la phase aiguë et chronique de l&#39;infection bactérienne 3. Ils induisent la réaction inflammatoire nécessaire pour éliminer les micro-organismes pathogènes, et de coordonner la résolution de l&#39;inflammation, comme l&#39;inflammation des macrophages induite persiste aussi longtemps que les tissus nécrotiques ne sont pas supprimés, ce qui empêche la réparation de commencer 4. Ainsi, la réduction de l&#39;infiltration macrophagique au sein de synovie infecté après un traitement efficace peut être un indicateur fiable de la résolution de l&#39;infection. L&#39;imagerie cellulaire est capable de démontrer infiltration cellulaire spécifique à l&#39;intérieur de tissu pathologique. Spécifique IRM macrophage aide ciblée agent de contraste a été largement étudié et a démontré sa capacité à démontrer l&#39;inflammation des articulations ou d&#39;infection 5-7. Après injection intraveineuse, ces agents de contraste ciblées comme USPIO particules (ultrapetites oxydes de fer superparamagnétiques) sont absorbés par les cellules phagocytaires telles que les macrophages et,en raison de leurs propriétés magnétiques, induire des changements de signaux dans les tissus présentant infiltration macrophagique 8. Le suivi longitudinal de ceux MR signal de modifications traitement permet une évaluation non invasive in vivo à l&#39;infiltration des macrophages, et une réduction des USPIO-macrophages chargés changements de signal liées démontrerait le succès de la thérapie. Le but de ce rapport est de présenter comment effectuer l&#39;IRM macrophage de surveiller de manière non invasive arthrite septique en démontrant la réduction de l&#39;infiltration des macrophages dans le liquide synovial.

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>P904</td>
			<td>Guerbet</td>
			<td></td>
			<td>Dose: 150 &#956;mol Fe/kg</td>
		</tr>
		<tr>
			<td>Ketamine (500 mg/ml ketamine)</td>
			<td>Virbac</td>
			<td></td>
			<td>Dose: 30 mg/kg</td>
		</tr>
		<tr>
			<td>Rompun (20 mg/ml Xylazine)</td>
			<td>Axience</td>
			<td></td>
			<td>Dose: 4 mg/kg</td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Vetoquinol</td>
			<td></td>
			<td>Dose: 0.1 mg/kg/8 hr</td>
		</tr>
		<tr>
			<td>BD 22 G, 1 inch</td>
			<td>BD Biosciences</td>
			<td>381423</td>
			<td></td>
		</tr>
		<tr>
			<td>BD 25 G, 5/8 inch</td>
			<td>BD Biosciences</td>
			<td>305122</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vivo macrophage imaging using mr targeted contrast agent for longitudinal evaluation of septic arthritis

Les macrophages sont des cellules clés dans l&#39;initiation, le développement et la régulation de la réponse inflammatoire à une infection bactérienne. Les macrophages sont de plus en plus intensive et recrutés dans les articulations septiques dès les premières phases de l&#39;infection et l&#39;infiltration est censé régresser une fois l&#39;élimination efficace des agents pathogènes est obtenue. La capacité d&#39;identifier l&#39;activité des macrophages in vivo dans une articulation infectée peut donc fournir deux applications principales: la détection précoce de la synovite aiguë et le suivi du traitement. In vivo, la détection non invasive des macrophages peut être réalisée avec l&#39;imagerie par résonance magnétique en utilisant des nanoparticules de fer tels que ultrapetites oxyde de fer superparamagnétique (USPIO). Après administration intravasculaire ou intra-articulaire, USPIO sont spécifiquement phagocytées par des macrophages activés, et, en raison de leurs propriétés magnétiques, induire des changements de signaux dans les tissus présentant une infiltration macrophagique. A quantitativl&#39;évaluation de l&#39;e de l&#39;infiltrat est possible, que la zone de perte de signal (nombre de pixels noirs) observée sur gradient echo images par résonance magnétique après que les particules d&#39;injection est en corrélation avec la quantité de fer dans le tissu et reflète donc le nombre de cellules USPIO-chargés. Nous présentons ici un protocole pour réaliser une imagerie de macrophages en utilisant USPIO-l&#39;IRM dans un modèle animal d&#39;arthrite septique, ce qui permet une première et longitudinales dans l&#39;évaluation non invasive in vivo des macrophages infiltration et une évaluation des mesures de thérapie.

Sur les images non améliorés, la synoviale des genoux infectés présente un gonflement diffus du signal intermédiaire qui est non distinguée de tissu mou environnant, tandis que le fémur et la rotule apparaissent comme des structures de signal bas (figure 1). Sur les images USPIO-améliorées, 24 heures après l&#39;administration de l&#39;agent de contraste, la zone synovial contenant macrophages USPIO chargés fera la démonstration de la perte de signal (fig...

Watch this Scientific Journal Video about In vivo Macrophage Imaging Using MR Targeted Contrast Agent for Longitudinal Evaluation of Septic Arthritis at JoVE.com

In vivo Macrophage Imaging Using MR Targeted Contrast Agent for Longitudinal Evaluation of Septic Arthritis

Nous démontrons comment effectuer l&#39;IRM macrophages en utilisant ultrapetites agent de contraste superparamagnétique (USPIO) dans l&#39;arthrite septique, ce qui permet une première et longitudinale<em&gt; In vivo</em&gt; Évaluation non invasive de macrophages infiltration et une évaluation de l&#39;efficacité du traitement.

In vivo des macrophages imagerie utilisant MR ciblée agent de contraste pour l&#39;évaluation longitudinale d&#39;arthrite septique

Macrophages are key-cells in the initiation, the development and the regulation of the inflammatory response to bacterial infection. Macrophages are ...

in-vivo-macrophage-imaging-using-mr-targeted-contrast-agent-for

Research

JoVE Journal

Medicine

In vivo Macrophage Imaging Using MR Targeted Contrast Agent for Longitudinal Evaluation of Septic Arthritis

9.2K vues.  University Hospital of Strasbourg. Nous démontrons comment effectuer l'IRM macrophages en utilisant ultrapetites agent de contraste superparamagnétique (USPIO) dans l'arthrite septique, ce qui permet une première et longitudinale In vivo Évaluation non invasive de macrophages infiltration et une évaluation de l'efficacité du traitement.

Vidéo: In vivo Macrophage Imaging Using MR Targeted Contrast Agent for Longitudinal Evaluation of Septic Arthritis

Contrast Enhanced Vessel Imaging using MicroCT

Microscopic computed tomography (microCT) offers high-resolution volumetric imaging of the anatomy of living small animals. However, the contrast between different soft tissues and body fluids is inherently poor in micro-CT images 1. Under these circumstances, visualization of blood vessels becomes a nearly impossible task. To overcome this and to improve the visualization of blood vessels exogenous contrast agents can be used. Herein, we present a methodology for visualizing the vascular network in a rodent model. By using a long-acting aqueous colloidal polydisperse iodinated blood-pool contrast agent, eXIA 160XL, we optimized image acquisition parameters and volume-rendering techniques for finding blood vessels in live animals. Our findings suggest that, to achieve a superior contrast between bone and soft tissue from vessel, multiple-frames (at least 5-8/ frames per view), and 360-720 views (for a full 360&deg; rotation) acquisitions were mandatory. We have also demonstrated the use of a two-dimensional transfer function (where voxel color and opacity was assigned in proportion to CT value and gradient magnitude), in visualizing the anatomy and highlighting the structure of interest, the blood vessel network. This promising work lays a foundation for the qualitative and quantitative assessment of anti-angiogenesis preclinical studies using transgenic or xenograft tumor-bearing mice.

Contrast enhanced small animal vessel imaging by microCT is a rapid, cost-effective and high-throughput technique for serial in situ examination for tumor development, for analyzing the network of blood vessels that nourish them, and for following the response of tumors to preclinical therapeutic intervention(s).

Imagerie navire Contraste rehaussé utilisant microCT

Microscopic computed tomography (microCT) offers high-resolution volumetric imaging of the anatomy of living small animals. However, the contrast between ...

Recherche

Médecine

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher frequency of fractures 1. As these fractures often occur in regions that have lost normal sensory function, the patient is at a greater risk of fracture-dependent pathologies, including death. SCI-dependent loss in both bone mineral density (BMD, grams/cm2) and bone mineral content (BMC, grams) has been attributed to mechanical disuse 2, aberrant neuronal signaling 3 and hormonal changes 4. The use of rodent models of SCI-induced osteoporosis can provide invaluable information regarding the mechanisms underlying the development of osteoporosis following SCI as well as a test environment for the generation of new therapies 5-7 (and reviewed in 8). Mouse models of SCI are of great interest as they permit a reductionist approach to mechanism-based assessment through the use of null and transgenic mice. While such models have provided important data, there is still a need for minimally-invasive, reliable, reproducible, and quantifiable methods in determining the extent of bone loss following SCI, particularly over time and within the same cohort of experimental animals, to improve diagnosis, treatment methods, and/or prevention of SCI-induced osteoporosis.
An ideal method for measuring bone density in rodents would allow multiple, sequential (over time) exposures to low-levels of X-ray radiation. This study describes the use of a new whole-animal scanner, the IVIS Lumina XR (Caliper Instruments) that can be used to provide low-energy (1-3 milligray (mGy)) high-resolution, high-magnification X-ray images of mouse hind limb bones over time following SCI. Significant bone density loss was seen in the tibiae of mice by 10 days post-spinal transection when compared to uninjured, age-matched control (na&iuml;ve) mice (13% decrease, p&lt;0.0005). Loss of bone density in the distal femur was also detectable by day 10 post-SCI, while a loss of density in the proximal femur was not detectable until 40 days post injury (7% decrease, p&lt;0.05). SCI-dependent loss of mouse femur density was confirmed post-mortem through the use of Dual-energy X-ray Absorptiometry (DXA), the current "gold standard" for bone density measurements. We detect a 12% loss of BMC in the femurs of mice at 40 days post-SCI using the IVIS Lumina XR. This compares favorably with a previously reported BMC loss of 13.5% by Picard and colleagues who used DXA analysis on mouse femurs post-mortem 30 days post-SCI 9. Our results suggest that the IVIS Lumina XR provides a novel, high-resolution/high-magnification method for performing long-term, longitudinal measurements of hind limb bone density in the mouse following SCI.

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

A longitudinal examination of bone loss in the femurs and tibiae of adult mice was performed following spinal cord injury using sequential low-dose X-ray scans. Tibia bone loss was detected throughout the study, while bone loss in the femur was not detected until 40 days post injury.

Évaluation longitudinale des souris Limb perte osseuse Hind après un traumatisme médullaire utilisant Novel, In vivo Méthodologie

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher ...

Transplantation into the Anterior Chamber of the Eye for Longitudinal, Non-invasive In vivo Imaging with Single-cell Resolution in Real-time

Intravital imaging has emerged as an indispensable tool in biological research. In the process, many imaging techniques have been developed to study different biological processes in animals non-invasively. However, a major technical limitation in existing intravital imaging modalities is the inability to combine non-invasive, longitudinal imaging with single-cell resolution capabilities. We show here how transplantation into the anterior chamber of the eye circumvents such significant limitation offering a versatile experimental platform that enables non-invasive, longitudinal imaging with cellular resolution in vivo. We demonstrate the transplantation procedure in the mouse and provide representative results using a model with clinical relevance, namely pancreatic islet transplantation. In addition to enabling direct visualization in a variety of tissues transplanted into the anterior chamber of the eye, this approach provides a platform to screen drugs by performing long-term follow up and monitoring in target tissues. Because of its versatility, tissue/cell transplantation into the anterior chamber of the eye not only benefits transplantation therapies, it extends to other in vivo applications to study physiological and pathophysiological processes such as signal transduction and cancer or autoimmune disease development.

Transplantation into the Anterior Chamber of the Eye for Longitudinal, Non-invasive In vivo Imaging with Single-cell Resolution in Real-time

A new approach combining intraocular transplantation and confocal microscopy enables longitudinal, non-invasive real-time imaging with single-cell resolution within grafted tissues in vivo. We demonstrate how to transplant pancreatic islets into the anterior chamber of the mouse eye.

Transplantation dans la chambre antérieure de l&#39;oeil pour longitudinale, non-invasive<em&gt; In vivo</em&gt; Imagerie avec une seule cellule de résolution en temps réel

Intravital imaging has emerged as an indispensable tool in biological research.  In the process, many imaging techniques have been developed to study ...

MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent

Tumor extracellular matrix has abundance of cancer related proteins that can be used as biomarkers for cancer molecular imaging. In this work, we demonstrated effective MR cancer molecular imaging with a small molecular peptide targeted Gd-DOTA monoamide complex as a targeted MRI contrast agent specific to clotted plasma proteins in tumor stroma. We performed the experiment of evaluating the effectiveness of the agent for non-invasive detection of prostate tumor with MRI in a mouse orthotopic PC-3 prostate cancer model. The targeted contrast agent was effective to produce significant tumor contrast enhancement at a low dose of 0.03 mmol Gd/kg. The peptide targeted MRI contrast agent is promising for MR molecular imaging of prostate tumor.

To demonstrate MR cancer molecular imaging with a small peptide targeted MRI contrast agent specific to clotted plasma proteins in tumor stroma in a mouse prostate cancer model.

M. imagerie moléculaire du cancer de la prostate avec un agent de contraste ciblé Petit moléculaire CLT1 Peptide

Tumor extracellular  matrix has abundance of cancer related proteins that can be used as biomarkers  for cancer molecular imaging. In this work,  we ...

In Vivo Optical Imaging of Brain Tumors and Arthritis Using Fluorescent SapC-DOPS Nanovesicles

We describe a multi-angle rotational optical imaging (MAROI) system for in vivo monitoring of physiopathological processes labeled with a fluorescent marker. Mouse models (brain tumor and arthritis) were used to evaluate the usefulness of this method. Saposin C (SapC)-dioleoylphosphatidylserine (DOPS) nanovesicles tagged with CellVue Maroon (CVM) fluorophore were administered intravenously. Animals were then placed in the rotational holder (MARS) of the in vivo imaging system. Images were acquired in 10&#176; steps over 380&#176;. A rectangular&#160;region of interest (ROI) was placed across the full image width at the model disease site. Within the ROI, and for every image, mean fluorescence intensity was computed after background subtraction. In the mouse models studied, the labeled nanovesicles were taken up in both the orthotopic and transgenic brain tumors, and in the arthritic sites (toes and ankles). Curve analysis of the multi angle image ROIs determined the angle with the highest signal. Thus, the optimal angle for imaging each disease site was characterized. The MAROI method applied to imaging of fluorescent compounds is a noninvasive, economical, and precise tool for in vivo quantitative analysis of the disease states in the described mouse models.

In Vivo Optical Imaging of Brain Tumors and Arthritis Using Fluorescent SapC-DOPS Nanovesicles

We describe a multi-angle rotational optical imaging (MAROI) system for in vivo quantitation of a fluorescent marker delivered by saposin C (SapC)-dioleoylphosphatidylserine (DOPS) nanovesicles. Employing mouse models of cancer and arthritis, we demonstrate how the MAROI signal curve analysis can be used for the precise mapping and biological characterization of disease processes.

In Vivo L&#39;imagerie optique de tumeurs cérébrales et l&#39;arthrite Utilisation fluorescent SAPC-DOPS nanovésicules

We describe a multi-angle rotational optical imaging (MAROI) system for in vivo monitoring of physiopathological processes labeled with a fluorescent ...

Longitudinal In Vivo Imaging of the Cerebrovasculature: Relevance to CNS Diseases

Remodeling of the brain vasculature is a common trait of brain pathologies. In vivo imaging techniques are fundamental to detect cerebrovascular plasticity or damage occurring overtime and in relation to neuronal activity or blood flow. In vivo two-photon microscopy allows the study of the structural and functional plasticity of large cellular units in the living brain. In particular, the thinned-skull window preparation allows the visualization of cortical regions of interest (ROI) without inducing significant brain inflammation. Repetitive imaging sessions of cortical ROI are feasible, providing the characterization of disease hallmarks over time during the progression of numerous CNS diseases. This technique accessing the pial structures within 250 &#956;m of the brain relies on the detection of fluorescent probes encoded by genetic cellular markers and/or vital dyes. The latter (e.g., fluorescent dextrans) are used to map the luminal compartment of cerebrovascular structures. Germane to the protocol described herein is the use of an in vivo marker of amyloid deposits, Methoxy-O4, to assess Alzheimer&#39;s disease (AD) progression. We also describe the post-acquisition image processing used to track vascular changes and amyloid depositions. While focusing presently on a model of AD, the described protocol is relevant to other CNS disorders where pathological cerebrovascular changes occur.

Longitudinal In Vivo Imaging of the Cerebrovasculature: Relevance to CNS Diseases

This manuscript describes a procedure to track the remodeling of the cerebrovasculature during amyloid plaque accumulation in vivo using longitudinal two-photon microscopy. A thinned-skull preparation enables the visualization of fluorescent dyes to assess the progression of cerebrovascular damage in a mouse model of Alzheimer&#39;s disease.

Longitudinal<em&gt; In Vivo</em&gt; Imagerie du Cerebrovasculature: Pertinence pour les maladies du système nerveux central

Remodeling of the brain vasculature is a common trait of brain pathologies. In vivo imaging techniques are fundamental to detect cerebrovascular ...

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

Phase contraste d’imagerie par résonance magnétique dans l’artère carotide commune de Rat

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

Quantitative [18F]-Naf-PET-MRI Analysis for the Evaluation of Dynamic Bone Turnover in a Patient with Facetogenic Low Back Pain

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. Bone is a dynamic tissue undergoing continuous remodeling with the competing activity of osteoblasts, which produce the new bone matrix, and osteoclasts, whose function is to eliminate mineralized bone. [18F]-NaF is a positron emission tomography (PET) radiotracer that enables visualization of bone metabolism. [18F]-NaF is chemically absorbed into hydroxyapatite in the bone matrix by osteoblasts and can thus noninvasively detect osteoblastic activity, which is occult to conventional imaging techniques. Kinetic modeling of dynamic [18F]-NaF-PET data provides detailed quantitative measures of bone metabolism. Conventional semi-quantitative PET data, which utilizes standardized uptake values (SUVs) as a measure of radiotracer activity, is referred to as a static technique due to its snapshot of tracer uptake in time.&#160; Kinetic modeling, however, utilizes dynamic image data where tracer levels are continuously acquired providing tracer uptake temporal resolution. From the kinetic modeling of dynamic data, quantitative values like blood flow and metabolic rate (i.e., potentially informative metrics of tracer dynamics) can be extracted, all with respect to the measured activity in the image data. When combined with dual modality PET-MRI, region-specific kinetic data can be correlated with anatomically registered high-resolution structural and pathologic information afforded by MRI. The goal of this methodological manuscript is to outline detailed techniques for performing and analyzing dynamic [18F]-NaF-PET-MRI data. The lumbar facet joint is a common site of degenerative arthritis disease and a common cause for axial low back pain.&#160; Recent studies suggest [18F]-NaF-PET may serve as a useful biomarker of painful facetogenic disease.&#160; The human lumbar facet joint will, therefore, be used as a prototypical region of interest for dynamic [18F]-NaF-PET-MRI analysis in this manuscript.

Quantitative [18F]-Naf-PET-MRI Analysis for the Evaluation of Dynamic Bone Turnover in a Patient with Facetogenic Low Back Pain

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. We present detailed methodologies for performing and analyzing dynamic [18F]-NaF-PET-MRI data in a patient with facetogenic low back pain using the lumbar facet joints as a prototypical region of interest.

Analyse quantitative [18F]-Naf-PET-MRI pour l'évaluation du chiffre d'affaires dynamique d'os dans un patient présentant la douleur lombaire facetogenic

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. Bone is a dynamic tissue undergoing ...

Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of the fresh gas entering a lung region divided by the region&#8217;s end-expiratory volume &#8213; in the human lung, using only inhaled oxygen as a contrast agent. Regional quantification of specific ventilation has the potential to help identify areas of pathologic lung function. Oxygen in solution in tissue shortens the tissue&#8217;s longitudinal relaxation time (T1), and thus a change in tissue oxygenation can be detected as a change in T1-weighted signal with an inversion recovery acquired image. Following an abrupt change between two concentrations of inspired oxygen, the rate at which lung tissue within a voxel equilibrates to a new steady-state reflects the rate at which resident gas is being replaced by inhaled gas. This rate is determined by specific ventilation. To elicit this sudden change in oxygenation, subjects alternately breathe 20-breath blocks of air (21% oxygen) and 100% oxygen while in the MRI scanner. A stepwise change in inspired oxygen fraction is achieved through use of a custom three-dimensional (3D)-printed flow bypass system with a manual switch during a short end-expiratory breath hold. To detect the corresponding change in T1, a global inversion pulse followed by a single shot fast spin echo sequence was used to acquire two-dimensional T1-weighted images in a 1.5&#160;T MRI scanner, using an eight-element torso coil. Both single slice and multi-slice imaging are possible, with slightly different imaging parameters. Quantification of specific ventilation is achieved by correlating the time-course of signal intensity for each lung voxel with a library of simulated responses to the air/oxygen stimulus. SVI estimations of specific ventilation heterogeneity have been validated against multiple breath washout and proved to accurately determine the heterogeneity of the specific ventilation distribution.

Specific ventilation imaging is a functional magnetic resonance imaging technique that allows for quantification of regional specific ventilation in the human lung, using inhaled oxygen as a contrast agent. Here, we present a protocol to collect and analyze specific ventilation imaging data.

Cartographie quantitative de la ventilation spécifique dans le poumon humain utilisant l’imagerie par résonance magnétique de proton et l’oxygène comme agent de contraste

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of ...

Stabilized Longitudinal In Vivo Cellular-Level Visualization of the Pancreas in a Murine Model with a Pancreatic Intravital Imaging Window

Direct in vivo cellular-resolution imaging of the pancreas in a live small animal model has been technically challenging. A recent intravital imaging study, with an abdominal imaging window, enabled visualization of the cellular dynamics in abdominal organs in vivo. However, due to the soft sheet-like architecture of the mouse pancreas that can be easily influenced by physiologic movement (e.g., peristalsis and respiration), it was difficult to perform stabilized longitudinal in vivo imaging over several weeks at the cellular level to identify, track, and quantify islets or cancer cells in the mouse pancreas. Herein, we describe a method for implanting a novel supporting base, an integrated pancreatic intravital imaging window, that can spatially separate the pancreas from the bowel for longitudinal time-lapse intravital imaging of the pancreas microstructure. Longitudinal in vivo imaging with the imaging window enables stable visualization, allowing for the tracking of islets over a period of 3 weeks and high-resolution three-dimensional imaging of the microstructure, as evidenced here in an orthotopic pancreatic cancer model. With our method, further intravital imaging studies can elucidate the pathophysiology of various diseases involving the pancreas at the cellular level.

Stabilized Longitudinal In Vivo Cellular-Level Visualization of the Pancreas in a Murine Model with a Pancreatic Intravital Imaging Window

In vivo high-resolution imaging of the pancreas was facilitated with the pancreatic intravital imaging window.

Visualisation longitudinale stabilisée au niveau cellulaire in vivo du pancréas dans un modèle murin avec une fenêtre d’imagerie intravitale pancréatique

Direct in vivo cellular-resolution imaging of the pancreas in a live small animal model has been technically challenging. A recent intravital imaging ...