Questo lavoro è stato sostenuto da sovvenzioni dal Ministero della scienza e della tecnologia, Taiwan, sotto il numero di concessione di MOST-105-2314-B-039-044-MY2.

La cura istituzionale e uso comitati (IACUC) di China Medical University ha approvato tutte le procedure.
1. animale preparazione e monitoraggio
<ol><li>Lasciare tutti gli oggetti magneticamente suscettibili quali portafogli, chiavi, carta di credito, ecc. all'esterno della camera dello scanner prima di iniziare la preparazione degli animali per l'esame di MRI.</li>
	<li>Inizialmente anestetizzare il rat (ratto Sprague-Dawley (deviazione standard) maschio di 2 mesi, 280 – 350 g) in una scatola di induzione utilizzando una miscela di 5% isoflurane (ISO) e ossigeno (2 L/min) per 3 – 5 min, se necessario.</li>
	<li>Quando l'animale è recumbent e non mostre nessuna risposta a un pizzico di punta o coda, interrompere la somministrazione di ISO e trasferire l'animale nella stanza di scansione.</li>
	<li>Posizionare il ratto nel letto MRI in posizione prona a capofitto e consegnare 2-3% ISO attraverso un dispositivo di cono di naso per mantenere l'anestesia.</li>
	<li>Respirazione di monitor posizionando un sensore respiratoria cuscino sotto il busto dell'animale.</li>
	<li>Collegare il sensore a un sistema respiratorio e verificare per tasso respiratorio tra 40-50 battiti al minuto (bpm).</li>
	<li>Per l'acquisizione di PC-MRI cine-gated, posizionare un elettrodo ogni sulla zampa anteriore destra e la sinistra posteriore della zampa, rispettivamente (Figura 1a).</li>
	<li>Attorcigliare i cavi di elettrocardiografia (ECG).</li>
	<li>Utilizzare un supporto per testine con orecchio bar e un morso per proteggere l'animale per limitare il movimento della testa.</li>
	<li>Utilizzare un sistema o una garza pastiglie di riscaldamento ad aria per mantenere la temperatura corporea mentre nel magnete.</li>
	<li>Assicurarsi che l'onda R è chiaro sul monitor ECG (Figura 1b) e inserire l'animale nello scanner. Non c'è nessun bisogno di posizionare la bobina di superficie nella parte superiore il collo dell'animale come immagini vengono acquisite dalla bobina di volume.</li>
</ol>2. MRI acquisizione
<ol><li>Utilizzare 2 – 3% ISO per mantenere l'anestesia durante l'intera procedura di imaging. Monitorare continuamente le risposte fisiologiche e mantenere quanto più possibile costante.</li>
	<li>Avviare le scansioni MRI, una volta che l'animale è posto all'interno dello scanner e continua ad essere fisiologicamente stabile. In questo studio, utilizzare un animale di piccola T 7 sistema MRI con una resistenza di pendenza di 630 metri, ma possono essere utilizzati altri punti di forza di campo di sistemi MRI per piccoli animali.</li>
	<li>Selezionare la sequenza di "Localizzatore" dal monitor console dello scanner MRI e acquisire immagini scout lungo tutti e tre gli orientamenti utilizzando qualsiasi sequenza di acquisizione rapida delle immagini, ad esempio, l'eco di rotazione veloce, per creare coronale, assiale e immagini sagittali . Lo scopo di questi scout immagini consiste nel determinare i piani di formazione immagini.</li>
	<li>Assicurarsi che il centro della testa e del collo dell'animale è al centro del magnete. Se necessario, regolare la posizione dell'animale fino a quando non viene raggiunta la posizione corretta. Se l'animale viene riposizionata, ripetere la scansione per ottenere immagini scout.</li>
	<li>Selezionare la sequenza di "tempo di volo (TOF) angiogramma" dal monitor console dello scanner MRI e acquisire un angiogramma 2D TOF in primo luogo per accertare l'esatta posizione anatomica del CCA. Utilizzare i seguenti parametri di scansione: ripetizione tempo (TR) / echo tempo (TE) = 22/4,87 ms, flip angolo = 90°, campo visivo (FOV) = 40 × 40 mm2, dimensione della matrice = 256 × 256, spessore 0,6 mm, con il numero di eccitazione (NEX) = 1. Nota: Il nome della sequenza TOF potrebbe essere vender-specifici. L'utente può inserire questi parametri nel monitor console.</li>
	<li>Assicurarsi che la band di saturazione è "on" ed è posizionata sulla parte superiore per evitare le interferenze da segnali di venosi. Nota: Per la band di saturazione, viene solitamente con la sequenza TOF. Se la banda di saturazione non viene visualizzato sul monitor, si prega di avvisare la persona di servizio.</li>
	<li>Dopo aver individuato il CCA utilizzando l'angiogramma TOF, il piano dell'immagine del PC-MRI al centro del CCA di destinazione e orientare tale che la fetta è perpendicolare alla direzione di flusso sanguigno (Figura 2a).</li>
	<li>Assicurarsi che la respirazione sia ECG gating sono collegati al sistema MRI, mostrando il chiaro segnale del computer monitor (Figura 1b) e impostare il modulo trigger di essere "on" in "modalità operativa" dal monitor console dello scanner MRI.</li>
	<li>Confermare che le risposte fisiologiche dell'animale sono stabili prima di iniziare la scansione del PC-MRI dal monitoraggio computer (Figura 1b). Verificare che le selezioni Gate sono "on" nel monitor computer e il monitor console di scanner MRI. Nota: La fisiologia monitoraggio sistema utilizzato in questo studio è fornita dal vender. Per gli scanner più animali, i sistemi di monitoraggio di fisiologia simili sono forniti e vender-specifici.</li>
	<li>Selezionare la sequenza di sequenza di PC-MRI dal monitor console dello scanner MRI ed eseguire scansioni del PC-MRI gated utilizzando i seguenti parametri: TR/TE=15.55/4.51 ms (minimo TR e TE), flip angle = 30°, FOV = 40 × 40 mm2, dimensione della matrice = 192 × 192, fetta spessore = 2 mm, velocità di codifica (VENC) = 120 cm/s, con NEX = 8. VENC unidirezionale viene acquisito nella direzione del attraverso-piano. Nota: Il tempo di scansione è di circa 8,5 min, ma il tempo di scansione effettiva può essere leggermente diverso tra gli animali a causa della variazione nei cicli cardiaci.</li>
	<li>Ripetere i passaggi da 2.6 – 2,9 di acquisizione dell'immagine se la regione di interesse (ROI) è di essere cambiato in un'altra posizione del CCA, come ad esempio presso la biforcazione 4.</li>
	<li>Rimuovere l'animale dallo scanner e restituirlo alla sua gabbia di recupero quando la scansione è completata.</li>
	<li>Caldo l'animale con una lampada riscaldante per mantenere la temperatura corporea. Tenere la lampada almeno 15 cm dall'animale per evitare il surriscaldamento.</li>
	<li>Quando l'animale comincia a muoversi ed esibisce una risposta ad un pizzico di punta o coda, spegnere la lampada di riscaldamento.</li>
</ol>3. elaborazione dei dati
<ol><li>Salvare i dati di MRI in Digital Imaging and Communications in formato medicina (DICOM) o qualsiasi altro formato di vender-specifici. Generare la serie cine con due tipi di immagini: una grandezza immagine (anatomia) e un'immagine di fase (Figura 2b). Nota: In alcuni scanner, il terzo tipo di immagine, che potrebbe essere l'immagine di grandezza immagine × fase o il complesso-differenza (sottrazione complessa tra le due acquisizioni con diversi gradienti di velocità di codifica), viene generato. La terza immagine è dipendente dal fornitore.</li>
	<li>Pre-elaborare i dati di immagine. Segreta la fase immagine nella mappa delle velocità e correggere l'errore di offset di fase 5. Nota: L'immagine di fase ha un'unità di MR arbitraria dell'intensità del segnale invece di valori della velocità vera, ma l'intensità di segnale del signor è linearmente proporzionale alla velocità. Il massimo segnale di MRI dall'immagine fase in genere viene assegnato come valore di VENC e il minimo segnale viene assegnato il valore opposto di VENC. Vedere file di codice supplementare 1 per un esempio dello script Matlab e premere il pulsante di "eseguire".</li>
	<li>Delineare il ROI attentamente tracciando il contorno del CCA. Come l'arteria può dilatare e costruire durante le varie fasi cardiache, delineare ROIs per ogni intervallo di tempo. Calcolare il flusso di sangue integrando sopra l'arteria ROI, cioè, velocità × area. Il flusso di sangue è derivato di ogni arteria era nelle unità di mL/s. Vedere file di codice supplementare 2 per un esempio dello script Matlab e premere il pulsante di "eseguire".</li>
</ol>

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Non c'è niente di divulgare.

PC-MRI è un approccio globale per la valutazione non invasiva e longitudinale del flusso sanguigno. Vi presentiamo un protocollo per l'esecuzione di PC-MRI del ratto CCA. Questa procedura è facile da eseguire in qualsiasi animale scanner MRI e dimostra buona riproducibilità.
La tecnica di PC-MRI ha guadagnato la popolarità aumentante in umano 10,11 , nonché gli studi sugli animali 4,<sup class="x...

La formazione immagine a risonanza magnetica (MRI) è un approccio versatile che fornisce informazioni dettagliate sulla fisiologia e strutture interne del corpo e sempre più sta usanda per la diagnosi clinica e negli studi sugli animali preclinici. Modelli animali sono vitali per una migliore comprensione di notevole implicazione clinica 1. Come modelli animali differiscono notevolmente da esseri umani per quanto riguarda l'anestesia requisiti e parametri fisiologici, ottimizzazione delle procedure di MRI per tali animali assume importanza.
MRI di contrasto di fase (PC-MRI) è un tipo specializzato di MRI che utilizza la velocità dei giri che scorre per quantificare il flusso relativi parametri quali il flusso di sangue. Con PC-MRI, mappatura schemi di flusso nelle arterie principali utilizzando modelli animali può aiutare a fare luce su patologie cardiovascolari 2. Inoltre, PC-MRI non invadente può monitorare le alternanze insite nel flusso sanguigno in condizioni fisiopatologiche 3. Queste osservazioni suggeriscono che PC-MRI è un valido approccio che può essere utilizzato nei modelli animali di malattie cardiovascolari.
In questo rapporto, descriviamo un metodo per la quantificazione del flusso sanguigno nell'arteria carotica comune (CCA) dei ratti. I due CCAs fornire la testa ed il collo con sangue ossigenato, e la malattia dell'arteria carotica è delle principali cause di ictus. Pertanto, rilevando la patologia iniziale in CCA è fondamentale. Questa procedura ha una durata di circa 15 min e potenzialmente applicabile a condizioni con alterazioni di emodinamica, tale aterosclerosi o ictus.

<table border="0" cellpadding="0" cellspacing="0" width="875">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">7T small animal MRI system</td>
			<td style="width:123px;">Bruker</td>
			<td style="width:344px;"></td>
			<td style="width:193px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Isoflurane&#160;</td>
			<td>Baxter</td>
			<td>1001936040</td>
			<td>anesthetic</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">ECG lead&#160;</td>
			<td>3M</td>
			<td>2269T</td>
			<td style="width:193px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Matlab</td>
			<td>MathWorks</td>
			<td></td>
			<td>sofeware for image processing</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Monitoring and gating system</td>
			<td>SA instruments, Inc</td>
			<td>Model 1030</td>
			<td style="width:193px;"></td>
		</tr>
	</tbody>
</table>

phase contrast magnetic resonance imaging in the rat common carotid artery

Fase di contrasto risonanza magnetica (PC-MRI) è un approccio non invasivo che può quantificare il flusso relativi parametri quali il flusso di sangue. Gli studi precedenti hanno indicato che il flusso sanguigno anormale può essere associato con il rischio vascolare sistemico. Quindi, PC-MRI può facilitare la traduzione dei dati ottenuti da modelli animali di malattie cardiovascolari a indagini cliniche pertinenti. In questo rapporto, descriviamo la procedura per la misurazione del flusso sanguigno nell'arteria carotica comune (CCA) di ratti utilizzando cine-gated PC-MRI e discutere i metodi di analisi pertinenti. Questa procedura può essere eseguita in un animale vivo, anestetizzato e non richiede l'eutanasia dopo la procedura. I parametri di scansione proposti resa misurazioni ripetibili per il flusso di sangue, che indica eccellente riproducibilità dei risultati. La procedura di PC-MRI descritta in questo articolo può essere utilizzata per test farmacologici, valutazione patofisiologica e valutazione emodinamica cerebrale.

Corretta fetta della geometria è fondamentale per garantire il successo dell'esperimento PC-MRI. Il posizionamento di un'immagine precisa aereo produce una forma di "turno" dell'arteria (Figura 3a), e come l'angolazione aumenta, vale a dire, quando è meno perpendicolare all'arteria, la geometria risultante dell'arteria diventa Ovo, portando a maggiore volume parziale effetti (Figura 3b). Effetti di volume parziale seve...

Watch this Scientific Journal Video about Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery at JoVE.com

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

L'obiettivo generale di questa procedura è quello di misurare il flusso sanguigno nell'arteria carotica comune ratto utilizzando la risonanza magnetica di contrasto di fase non invadente.

Fase di contrasto risonanza magnetica nell'arteria carotica comune ratto

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

phase-contrast-magnetic-resonance-imaging-rat-common-carotid

Research

JoVE Journal

Medicine

9.4K Views.  Chang Gung Memorial Hospital. L'obiettivo generale di questa procedura è quello di misurare il flusso sanguigno nell'arteria carotica comune ratto utilizzando la risonanza magnetica di contrasto di fase non invadente.

Video: Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

Risonanza Magnetica Derivato valutazione di deformazione miocardica Utilizzo del rilevamento delle caratteristiche

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

Ricerca

Medicina

Training a Sophisticated Microsurgical Technique: Interposition of External Jugular Vein Graft in the Common Carotid Artery in Rats

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in peripheral arterial bypass surgery as well as in arteriovenous fistulas.1-5 The experimental procedure of vein graft interposition in the common carotid artery by using the cuff-technique has been applied in several research projects to examine the aetiology of neointimal hyperplasia and therapeutic options to address it. 6-8 The cuff prevents vessel anastomotic remodeling and induces turbulence within the graft and thereby the development of neointimal hyperplasia.
Using the superior caval vein graft is an established small-animal model for venous arterialization experiment.9-11 This current protocol refers to an established jugular vein graft interposition technique first described by Zou et al., 9 as well as others.12-14 Nevertheless, these cited small animal protocols are complicated.
To simplify the procedure and to minimize the number of experimental animals needed, a detailed operation protocol by video training is presented. This video should help the novice surgeon to learn both the cuff-technique and the vein graft interposition. Hereby, the right external jugular vein was grafted in cuff-technique in the common carotid artery of 21 female Sprague Dawley rats categorized in three equal groups that were sacrificed on day 21, 42 and 84, respectively. Notably, no donor animals were needed, because auto-transplantations were performed. The survival rate was 100 % at the time point of sacrifice. In addition, the graft patency rate was 60 % for the first 10 operated animals and 82 % for the remaining 11 animals. The blood flow at the time of sacrifice was 8&plusmn;3 ml/min. In conclusion, this surgical protocol considerably simplifies, optimizes and standardizes this complicated procedure. It gives novice surgeons easy, step-by-step instruction, explaining possible pitfalls, thereby helping them to gain expertise fast and avoid useless sacrifice of experimental animals.

Neointimal hyperplasia is the primary cause of stenosis in arterialized veins. We propose a new protocol whereby the right external jugular vein is grafted using the cuff technique in the common carotid artery of Sprague Dawley rats. The survival rate was 100 % at the time point of sacrifice.

La formazione di una sofisticata tecnica microchirurgica: Interposizione della vena giugulare esterna innesto nella carotide comune in Rats

Neointimal hyperplasia is one the primary causes of stenosis in arterialized veins that are of great importance in arterial coronary bypass surgery, in ...

Multi-modal Imaging of Angiogenesis in a Nude Rat Model of Breast Cancer Bone Metastasis Using Magnetic Resonance Imaging, Volumetric Computed Tomography and Ultrasound

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques.
For this purpose, we injected 105 MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg1. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula1. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US).
MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified2-4. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions5,6. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles7.
In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.

In the pathogenesis of bone metastasis, angiogenesis is a crucial process and therefore represents a target for imaging and therapy. Here, we present a rat model of site-specific breast cancer bone metastasis and describe strategies to non-invasively image angiogenesis in vivo using magnetic resonance imaging, volumetric computed tomography and ultrasound.

Multi-modal Imaging di angiogenesi in un modello di ratto Nudo di metastasi ossee cancro al seno utilizzando la risonanza magnetica, tomografia computerizzata volumetrica e Ultrasuoni

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell ...

A Murine Model of Stent Implantation in the Carotid Artery for the Study of Restenosis

Despite the considerable progress made in the stent development in the last decades, cardiovascular diseases remain the main cause of death in western countries. Beside the benefits offered by the development of different drug-eluting stents, the coronary revascularization bears also the life-threatening risks of in-stent thrombosis and restenosis. Research on new therapeutic strategies is impaired by the lack of appropriate methods to study stent implantation and restenosis processes. Here, we describe a rapid and accessible procedure of stent implantation in mouse carotid artery, which offers the possibility to study in a convenient way the molecular mechanisms of vessel remodeling and the effects of different drug coatings.

A model of stent implantation in mouse carotid artery is described. Compared to other similar methods, this procedure is very rapid, simple and accessible, offering the possibility to study in a convenient way the vascular wall reaction to different drug-eluting stents and the molecular mechanisms of restenosis.

Un modello murino di impianto di stent a livello dell&#39;arteria carotidea per lo Studio della restenosi

Despite  the considerable progress made in the stent development in the last decades,  cardiovascular diseases remain the main cause of death in western ...

Adult Mouse Venous Hypertension Model: Common Carotid Artery to External Jugular Vein Anastomosis.

The understanding of the pathophysiology of brain arteriovenous malformations and arteriovenous fistulas has improved thanks to animal models. A rat model creating an artificial fistula between the common carotid artery (CCA) and the external jugular vein (EJV) has been widely described and proved technically feasible. This construct provokes a consistent cerebral venous hypertension (CVH), and therefore has helped studying the contribution of venous hypertension to formation, clinical symptoms, and prognosis of brain AVMs and dural AVFs. Equivalent mice models have been only scarcely described and have shown trouble with stenosis of the fistula. An established murine model would allow the study of not only pathophysiology but also potential genetic therapies for these cerebrovascular diseases.
We present a model of arteriovenous fistula that produces a durable intracranial venous hypertension in the mouse. Microsurgical anastomosis of the murine CCA and EJV can be difficult due to diminutive anatomy and frequently result in a non-patent fistula. In this step-by-step protocol we address all the important challenges encountered during this procedure. Avoiding excessive retraction of the vein during the exposure, using 11-0 sutures instead of 10-0, and making a carefully planned end-to-side anastomosis are some of the critical steps. Although this method requires advanced microsurgical skills and a longer learning curve that the equivalent in the rat, it can be consistently developed.
This novel model has been designed to integrate transgenic mouse techniques with a previously well-established experimental system that has proved useful to study brain AVMs and dural AVFs. By opening the possibility of using transgenic mice, a broader spectrum of valid models can be achieved and genetic treatments can also be tested. The experimental construct could also be further adapted to the study of other cerebrovascular diseases related with venous hypertension such as migraine, transient global amnesia, transient monocular blindness, etc.

We describe a method for creating a reliable model of cerebral venous hypertension in the adult mouse. This model has been widely described and tested in the rat. This new counterpart in the mice opens the possibility of using genetic modified animals and thereby broadens the applications of the model.

Topo adulto venosa Ipertensione Modello: carotide comune di External Vena giugulare anastomosi.

The understanding of the pathophysiology of brain arteriovenous malformations and arteriovenous fistulas has improved thanks to animal models. A rat model ...

Vascular Balloon Injury and Intraluminal Administration in Rat Carotid Artery

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and cellular mechanisms involved in vascular smooth muscle dedifferentiation, neointima formation and vascular remodeling. Male Sprague-Dawley rats are the most frequently employed animals for this model. Female rats are not preferred as female hormones are protective against vascular diseases and thus introduce a variation into this procedure. The left carotid is typically injured with the right carotid serving as a negative control. Left carotid injury is caused by the inflated balloon that denudes the endothelium and distends the vessel wall. Following injury, potential therapeutic strategies such as the use of pharmacological compounds and either gene or shRNA transfer can be evaluated. Typically for gene or shRNA transfer, the injured section of the vessel lumen is locally transduced for 30 min with viral particles encoding either a protein or shRNA for delivery and expression in the injured vessel wall. Neointimal thickening representing proliferative vascular smooth muscle cells usually peaks at 2 weeks after injury. Vessels are mostly harvested at this time point for cellular and molecular analysis of cell signaling pathways as well as gene and protein expression. Vessels can also be harvested at earlier time points to determine the onset of expression and/or activation of a specific protein or pathway, depending on the experimental aims intended. Vessels can be characterized and evaluated using histological staining, immunohistochemistry, protein/mRNA assays, and activity assays. The intact right carotid artery from the same animal is an ideal internal control. Injury-induced changes in molecular and cellular parameters can be evaluated by comparing the injured artery to the internal right control artery. Likewise, therapeutic modalities can be evaluated by comparing the injured and treated artery to the control injured only artery.

This protocol uses a balloon catheter to cause an intraluminal injury on the rat carotid artery and henceforth elicit neointimal hyperplasia. This is a well-established model for studying the mechanisms of vascular remodeling in response to injury. It is also widely used to determine the validity of potential therapeutic approaches.

Vascolare Balloon Lesioni e intraluminale Amministrazione in Rat carotide

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and ...

Dynamic Contrast Enhanced Magnetic Resonance Imaging of an Orthotopic Pancreatic Cancer Mouse Model

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe respiratory motion artifact in the abdominal area. Orthotopic tumor models offer advantages over subcutaneous ones, because those can reflect the primary tumor microenvironment affecting blood supply, neovascularization, and tumor cell invasion. We have recently established a protocol of DCE-MRI of orthotopic pancreatic tumor xenografts in mouse models by securing tumors with an orthogonally bent plastic board to prevent motion transfer from the chest region during imaging. The pressure by this board was localized on the abdominal area, and has not resulted in respiratory difficulty of the animals. This article demonstrates the detailed procedure of orthotopic pancreatic tumor modeling using small animals and DCE-MRI of the tumor xenografts. Quantification method of pharmacokinetic parameters in DCE-MRI is also introduced. The procedure described in this article will assist investigators to apply DCE-MRI for orthotopic gastrointestinal cancer mouse models.

The goal of this protocol is to apply dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) for orthotopic pancreatic tumor xenografts in mice. DCE-MRI is a non-invasive method to analyze microvasculature in a target tissue, and useful to assess vascular response in a tumor following a novel therapy.

Contrasto dinamico migliorato risonanza magnetica di un modello ortotopico cancro del pancreas mouse

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe ...

Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-&#7429;-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.

The method presented here uses simultaneous positron emission tomography and magnetic resonance imaging. In the cerebral hypoxia-ischemia model, dynamic changes in diffusion and glucose metabolism occur during and after injury. The evolving and irreproducible damage in this model necessitates simultaneous acquisition if meaningful multi-modal imaging data are to be acquired.

Simultanea Imaging PET / MRI Durante mouse cerebrale ipossia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

Risonanza magnetica cardiaca a 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves focal endothelial-selective transgenesis, thereby allowing an investigator to determine the biological roles of endothelial-expressed transgenes and to quantify the in vivo transcriptional activity of DNA sequences in large artery endothelial cells. The method uses surgical isolation of rabbit common carotid arteries and an arteriotomy to deliver a transgene-expressing viral vector into the arterial lumen. A short incubation period of the vector in the lumen, with subsequent aspiration of the lumen contents, is sufficient to achieve efficient and durable expression of the transgene in the endothelium, with no detectable transduction or expression outside of the isolated arterial segment. The method allows assessment of the biological activities of transgene products both in normal arteries and in models of human vascular disease, while avoiding systemic effects that could be caused either by targeting gene delivery to other sites (e.g. the liver) or by the alternative approach of delivering genetic constructs to the endothelium by germ line transgenesis. Application of the method is limited by the need for a skilled surgeon and anesthetist, a well-equipped operating room, the costs of purchasing and housing rabbits, and the need for expertise in gene-transfer vector construction and use. Results obtained with this method include: transgene-related alterations in arterial structure, cellularity, extracellular matrix, or vasomotor function; increases or reductions in arterial inflammation; alterations in vascular cell apoptosis; and progression, retardation, or regression of diseases such as intimal hyperplasia or atherosclerosis. The method also allows measurement of the ability of native and synthetic DNA regulatory sequences to alter transgene expression in endothelial cells, providing results that include: levels of transgene mRNA, levels of transgene protein, and levels of transgene enzymatic activity.

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

This method is to introduce a transgene into the endothelium of rabbit carotid arteries. Introduction of the transgene allows the assessment of the biological role of the transgene product either in normal arteries or disease models. The method is also useful for measuring activity of DNA regulatory sequences.

In Vivo Trasferimento del gene per l'endotelio dell'arteria carotica comune di coniglio

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves ...