We would like to thank the Vanderbilt University Institute of Imaging Science MRI technologists David Pennell, Leslie McIntosh, and Kristen George-Durrett, and the team of Vanderbilt University Medical Center PET/CT technologists led by Martha D. Shone. This work was supported by the following grants from the NIH: NCATS/NIH UL1 RR024975, NIDDK/NIH R21DK096282, NCI/NIH R25CA136440, and NIBIB/NIH T32EB014841.

The authors declare that they have no competing financial interests or other conflicts of interests.

El protocolo del estudio descrito está diseñado para utilizar tanto termoneutra y en frío activado PET / CT para automáticamente segmento depósitos IMPAC en forma específica tema. Estas regiones generadas automáticamente de interés, después se pueden aplicar tanto a imágenes por resonancia magnética termoneutrales y frío activado que han sido co-registradas a las exploraciones de PET / CT del mismo tema. A lo mejor de nuestro conocimiento, esta es la primera investigación para llevar a cabo tanto la RM y PE...

Debido al marcado aumento de la obesidad en todo el mundo, hay un mayor interés en las áreas de investigación destinados a comprender el balance energético. La obesidad puede provocar costosos y devastadores condiciones médicas tales como diabetes, enfermedad hepática, enfermedad cardiovascular y el cáncer, por lo que es un área importante de preocupación para la salud pública 1. Un área de investigación tuvo como objetivo comprender el equilibrio de la ingesta de energía en comparación con el gasto de energía es el estudio del tejido adiposo marrón o BAT. Aunque denominado un tejido adiposo, BAT difiere del tejido más común adiposo blanco (WAT) de muchas maneras 2. La función de los adipocitos blancos es almacenar triglicéridos en un solo gran vacuola lipídica por célula, y para liberar estos triglicéridos como fuente de energía en el torrente sanguíneo cuando sea necesario. De una manera muy diferente, la función de los adipocitos marrones es producir calor. Un mecanismo por el cual esto ocurre es a través de la exposición al frío. Esto provoca un aumento en sympathetic actividad del sistema nervioso, que a su vez activa BAT. Cuando se activa, los adipocitos marrones generan calor. Para ello, se utilizan los triglicéridos contenidos en las muchas pequeñas vacuolas lipídicas por célula, y por medio de la presencia de proteína desacoplante 1 (UCP1) en la abundante mitocondrias, convertir los triglicéridos a sustratos metabólicos sin la producción de ATP, lo que resulta en la pérdida entrópica como la generación de calor. Como los triglicéridos almacenados en las pequeñas vacuolas lipídicas se agotan, el adipocito ocupa tanto la glucosa y los triglicéridos presentes en el torrente sanguíneo 3. El interés en el estudio de BAT se ha incrementado dramáticamente en los últimos años debido a su contribución a la termogénesis sin temblor, su papel en la modulación de los gastos de energía del cuerpo, y el potencial de la relación inversa entre BAT y la obesidad 3-9. Además, los estudios recientes en animales indican BAT juega un papel crítico en los triglicéridos de compensación y la glucosa fesde la corriente de la sangre, especialmente después de la ingestión de una comida rica en grasas 10,11. Sin embargo, la mayor parte de lo que sabemos sobre MTD es el resultado de la investigación en pequeños mamíferos, que contienen muchos depósitos de BAT 4,9,12 - 15. A pesar de algunos de los primeros estudios 16-18, la presencia de las mejores técnicas en los seres humanos fue ampliamente cree que disminuye con la edad, hasta hace poco, cuando el interés por estudiar BAT humana ha sido renovado. Investigaciones recientes sugieren que cantidades relativamente pequeñas de BAT persisten en la edad adulta 19-24. Un factor limitante adicional para estudiar BAT es que, aparte de la biopsia y la tinción histológica, el método inequívoca actualmente aceptado para la detección de BAT es 18 F-fluorodesoxiglucosa (18 F-FDG) tomografía por emisión de positrones (PET). Modernos escáneres PET se suelen combinar con una tomografía computarizada (TC). Cuando es activado por la exposición al frío, BAT ocupa el 18 </sarriba&gt; radiotrazador F-FDG, que es un análogo del metabolismo de la glucosa, y se hace visible en las imágenes de PET, en comparación con el nivel mucho más bajo de 18 F-FDG captación cuando BAT es 20,21,23,25 inactivo. CT imágenes adquiridas durante un examen PET en un escáner PET-CT ayuda a diferenciar entre los tejidos con alta 18 F-FDG captación proporcionando información anatómica. Este uso de la PET-CT expone al sujeto a la radiación ionizante (predominantemente de PET, aunque la dosis de la exploración CT no es despreciable), y por lo tanto es un método deseable para la detección BAT. Aunque el número de estudios sobre MTD en los seres humanos adultos sanos es cada vez mayor, los estudios recientes de BAT humano principalmente se han limitado a retrospectivo PET-CT estudia 19,25, cadáveres infantiles humanos 26,27, adolescentes humanos que ya han sido admitidos en los hospitales para otras razones 27-30, y algunos estudios humanos de los adultos sanos31 - 35. Uno de los retos con los dos estudios de los niños y los estudios retrospectivos es la posibilidad de resultados alterados cuando se estudia una población de pacientes que está enfermo, que puede afectar a las MTD. Además, debido a la glucosa no es la fuente de combustible preferido de las MTD 36, los estudios de PET no siempre detectan BAT se activa, y por lo tanto pueden subrepresentar la presencia de las MTD. Otra dificultad en el estudio de BAT con imágenes biomédicas está relacionada con la realización de la segmentación de imágenes para definir los límites de los depósitos de tejido. Actualmente, la segmentación de BAT en estudios en humanos a menudo se basa en un cierto grado de segmentación de imágenes manual y es por lo tanto vulnerables a la identificación errónea de los depósitos de las MTD, así como la variabilidad entre los evaluadores. Debido a estos desafíos, las técnicas de cartografía espacial fiables que pueden distinguir BAT de las distribuciones de WAT, junto con métodos de segmentación automatizada, proporcionarían a los investigadores una nueva y poderosa paraol con el que estudiar las MTD. La resonancia magnética (MRI) tiene la capacidad para la identificación, mapeo espacial, y la cuantificación volumétrica de BAT, y a diferencia de los enfoques existentes de formación de imágenes híbridos PET-CT que incluyen una dosis radiactiva para el sujeto de captación de imagen, MRI implica ninguna radiación ionizante y se puede utilizar de forma segura y en repetidas ocasiones. La capacidad de identificar y cuantificar BAT mediante resonancia magnética puede tener un impacto positivo dramático en endocrinología clínica y la búsqueda de nuevas vías de investigación sobre la obesidad. Anterior MRI grasa-agua (FWMRI) estudios de BAT tanto en ratones como en humanos muestran que la grasa de señal fracción (FSF) de BAT está en el rango de 40 a 80% de grasa, mientras que WAT es superior al 90% de grasa 15,26 , 27. Por lo tanto, la hipótesis de que esta cuantitativo FWMRI métrica, junto con otras medidas de resonancia magnética cuantitativa, se puede utilizar en el trabajo futuro para visualizar y cuantificar los depósitos de las MTD en los seres humanos. Esto proporcionaría la comunidad de investigación con una herramienta poderosa para estudiar la influencia de BAT en conocidogastos abolism y energía sin el uso de radiación ionizante. Nuestro grupo de investigación ha estado estudiando BAT en humanos adultos en los últimos tres años. Nuestra primera presentación pública en el uso de la resonancia magnética para investigar las sospechas sobre MTD en sujeto humano un adulto se produjo en febrero de 2012 a la Sociedad Internacional de Resonancia Magnética en Medicina Taller (ISMRM) Separación Fat-Agua en Long Beach, California 37. Dos meses más tarde, nuestro grupo presentó valores de la FSF en sospecha de BAT en dos adultos en la 20ª reunión anual de la ISMRM en abril de 2012 en Melbourne, Australia 38. Un año después, en el 21 encuentro anual st del ISMRM en abril de 2013 en Salt Lake City, Utah, se utilizó el protocolo descrito en este manuscrito de la primera (a lo mejor de nuestro conocimiento) presentación pública de la RM cuantificación de confirmado-PET BAT en humano adulto somete 39. Concretamente, hemos presentado pruebas que demuestran que el previously sospecha de BAT se confirmó como MTD activable utilizando tanto imágenes 18 F-FDG PET-CT-frío activado y temperatura neutra. Desde 2013, nuestra cohorte de sujetos humanos sanos adultos fotografiada tanto con la RM y PET / CT en condiciones térmicamente neutras y en frío activado se ha expandido a más de 20 sujetos con resultados más recientemente presentados en febrero de 2014 el taller &quot;Explorando el Papel de la grasa marrón en los seres humanos &quot;, patrocinado por el NIH NIDDK 40. En concreto, se informó FWMRI FSF y R 2 * propiedades de relajación en las regiones de BAT supraclavicular confirmados por 18 F-FDG PET-TAC en los humanos adultos, con las ROI MTD delineado utilizando algoritmos de segmentación automatizada basada en el frío activado y termoneutra PET-CT exploraciones. Más recientemente hemos presentado los resultados del mapeo de temperatura en 18 F-FDG PET-TAC confirmó BAT en humanos adultos que utilizan avanzada termometría FWMRI 41,42. El procedimiento que aquí se presenta adquirirs tanto la RM y 18 exploraciones F-FDG PET-TC sobre el mismo tema, cada uno después de la exposición a condiciones tanto en frío activados y termoneutrales. Los 18 exploraciones F-FDG PET-CT-frías activado y termoneutrales se utilizan para crear regiones segmentadas automáticamente MTD de interés (ROI), sobre una base específica tema. Estas regiones de interés MTD se aplican a los co-registrado MRI para medir las propiedades de resonancia magnética en el PET-TAC confirmaron BAT. Una limitación de este protocolo es que la temperatura del aire utilizado al exponer los sujetos ya sea al estímulo frío o en caliente es consistente para cada sujeto. Esta es una limitación porque la temperatura a la que cada sujeto experimenta sensación de calor o refrigerados puede ser diferente. Por lo tanto, mediante la ejecución de una sesión de prueba durante el cual la temperatura del aire se ajusta para adaptarse a la respuesta del individuo y, a continuación, el uso de estas temperaturas durante los protocolos termoneutrales y frío de activación, que podría ser posible obtener mejores respuestasa partir del tejido adiposo marrón.

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		<tr height="100">
			<td height="100" style="height:100px;width:363px;">Name of Material/ Equipment</td>
			<td style="width:392px;">Company</td>
			<td style="width:375px;">Catalog Number</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">MRI</td>
			<td style="width:392px;">Philips</td>
			<td style="width:375px;">Achieva 3T</td>
		</tr>
		<tr height="68">
			<td height="68" style="height:68px;width:363px;">MRI Torso-XL coil</td>
			<td style="width:392px;">Philips</td>
			<td style="width:375px;">Philips SENSE XL Torso coil 16-elements</td>
		</tr>
		<tr height="68">
			<td height="68" style="height:68px;width:363px;">MRI X-tend Table</td>
			<td style="width:392px;">X-Tend</td>
			<td style="width:375px;">X-tend table, Acieva 3T compatible</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:363px;">X-tend armsupport</td>
			<td style="width:392px;">X-Tend</td>
			<td style="width:375px;">X-tend, accessories</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:363px;">X-tend fabricsling</td>
			<td style="width:392px;">X-Tend</td>
			<td style="width:375px;">X-tend, accessories</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">PET/CT</td>
			<td style="width:392px;">GE</td>
			<td style="width:375px;">Discovery STE</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Portable A/C Unit</td>
			<td style="width:392px;">Soleus Air</td>
			<td style="width:375px;">XL-140, 14000 BTU</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Floor fan</td>
			<td style="width:392px;">Lasko Pedestal Fan</td>
			<td style="width:375px;">2527</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Portable Heater</td>
			<td style="width:392px;">Lasko Ceramic Air</td>
			<td style="width:375px;">5536</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Chair</td>
			<td style="width:392px;">Winco Lifecare Recliner</td>
			<td style="width:375px;">585</td>
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		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Sublingual Thermometer</td>
			<td style="width:392px;">WelchAllyn</td>
			<td style="width:375px;">SureTemp Plus 690</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Cold vest</td>
			<td style="width:392px;">Polar Products</td>
			<td style="width:375px;">Cool58 #PCVZ</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:39px;width:363px;">Thermal IR Camera</td>
			<td style="width:392px;">FLUKE</td>
			<td style="width:375px;">TIR-125</td>
		</tr>
	</tbody>
</table>

human brown adipose tissue depots automatically segmented by positron emission tomography/computed tomography and registered magnetic resonance images

Fiable diferenciar el tejido adiposo marrón (BAT) de otros tejidos utilizando un método de imagen no invasivo es un paso importante para el estudio de BAT en los seres humanos. Detectar BAT se confirma típicamente por la captación del trazador radioactivo inyectado 18 F-fluorodeoxiglucosa (18 F-FDG) en los depósitos de tejido adiposo, tal como se mide mediante tomografía por emisión de positrones / tomografía computarizada (PET-TC) después de exponer el sujeto a estímulo frío . Imágenes por resonancia magnética separada grasa-agua (MRI) tiene la capacidad de distinguir BAT sin el uso de un trazador radioactivo. Hasta la fecha, la RM de BAT en humanos adultos no ha sido co-registrado en frío activado PET-CT. Por lo tanto, este protocolo utiliza 18 exploraciones F-FDG PET-CT para generar automáticamente una máscara de BAT, que se aplica luego a co-registrado IRM del mismo tema. Este enfoque permite la medición de las propiedades de resonancia magnética cuantitativos de BAT sin segmentación manual. Máscaras MTD son creados a partir de dos PEExploraciones T-CT: después de la exposición durante 2 horas a temperatura neutra o bien (TN) (24 ° C) o en frío activado (CA) (17 ° C) Condiciones. Las exploraciones de TN y CA PET-CT están registrados, y los valores de captación estandarizado PET y TC Hounsfield se utilizan para crear una máscara que contiene sólo BAT. CA y TN MRI también se adquieren en el mismo tema y se inscribieron para las exploraciones PET-TC con el fin de establecer las propiedades cuantitativas MRI dentro de la máscara BAT definido automáticamente. Una ventaja de este enfoque es que la segmentación está completamente automatizado y se basa en métodos ampliamente aceptados para la identificación de BAT activado (PET-CT). Las propiedades de resonancia magnética cuantitativas de la MTD establecen utilizando este protocolo puede servir como base para un solo-MRI examen BAT que evita la radiación asociada con PET-CT.

La adquisición tanto de MRI y PET-TC sobre el mismo tema, y la realización de co-registro en todas las exploraciones permite la medición fiable de las métricas de MRI cuantitativos de BAT. La figura 1 muestra el estado natural caliente (TN) y fría (CA) PET-TC y la RM scans de una asignatura. Con la adquisición de datos tanto TN y CA PET-CT, es posible distinguir claramente los depósitos de las MTD en frío activado por el aumento de la captación de 18 F-FDG. Después de co-registro de...

Watch this Scientific Journal Video about Human Brown Adipose Tissue Depots Automatically Segmented by Positron Emission Tomography/Computed Tomography and Registered Magnetic Resonance Images at JoVE

Human Brown Adipose Tissue Depots Automatically Segmented by Positron Emission Tomography/Computed Tomography and Registered Magnetic Resonance Images

El método presentado aquí utiliza 18 F-fluorodesoxiglucosa (18F-FDG) tomografía por emisión de positrones / tomografía computarizada (PET-TC) y la resonancia magnética separada grasa-agua (MRI), cada escaneado tras 2 horas de exposición a temperatura neutra (24 ° C ) y las condiciones de frío (17 ° C) para mapear el tejido adiposo marrón (BAT) en sujetos humanos adultos.

Depósitos de tejido adiposo humano Marrón segmentada automáticamente por Tomografía por Emisión de Positrones / Tomografía Computada y Resonancia Registrado Imágenes Magnéticas

Reliably differentiating brown adipose tissue (BAT) from other tissues using a non-invasive imaging method is an important step toward studying BAT in ...

human-brown-adipose-tissue-depots-automatically-segmented-positron

Research

JoVE Journal

Medicine

12.1K vistas.  Vanderbilt University.  El método presentado aquí utiliza 18 F-fluorodesoxiglucosa (18F-FDG) tomografía por emisión de positrones / tomografía computarizada (PET-TC) y la resonancia magnética separada grasa-agua (MRI), cada escaneado tras 2 horas de exposición a temperatura neutra (24 ° C ) y las condiciones de frío (17 ° C) para mapear el tejido adiposo marrón (BAT) en sujetos humanos adultos. 

Video: Human Brown Adipose Tissue Depots Automatically Segmented by Positron Emission Tomography/Computed Tomography and Registered Magnetic Resonance Images

Basic Surgical Techniques in the G&ouml;ttingen Minipig: Intubation, Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion

The emergence of the G&ouml;ttingen minipig in research of topics such as neuroscience, toxicology, diabetes, obesity, and experimental surgery reflects the close resemblance of these animals to human anatomy and physiology 1-6.The size of the G&ouml;ttingen minipig permits the use of surgical equipment and advanced imaging modalities similar to those used in humans 6-8. The aim of this instructional video is to increase the awareness on the value of minipigs in biomedical research, by demonstrating how to perform tracheal intubation, transurethral bladder catheterization, femoral artery and vein catheterization, as well as transcardial perfusion. 
Endotracheal Intubation should be performed whenever a minipig undergoes general anesthesia, because it maintains a patent airway, permits assisted ventilation and protects the airways from aspirates. Transurethral bladder catheterization can provide useful information about about hydration state as well as renal and cardiovascular function during long surgical procedures. Furthermore, urinary catheterization can prevent contamination of delicate medico-technical equipment and painful bladder extension which may harm the animal and unnecessarily influence the experiment due to increased vagal tone and altered physiological parameters. Arterial and venous catheterization is useful for obtaining repeated blood samples and monitoring various physiological parameters. Catheterization of femoral vessels is preferable to catheterization of the neck vessels for ease of access, when performing experiments involving frame-based stereotaxic neurosurgery and brain imaging. When performing vessel catheterization in survival studies, strict aseptic technique must be employed to avoid infections6. Transcardial perfusion is the most effective fixation method, and yields preeminent results when preparing minipig organs for histology and histochemistry2,9. For more information about anesthesia, surgery and experimental techniques in swine in general we refer to Swindle 2007. Supplementary information about premedication and induction of anesthesia, assisted ventilation, analgesia, pre- and postoperative care of G&ouml;ttingen minipigs are available via the internet at <a href="http://www.minipigs.com">http://www.minipigs.com</a>10. For extensive information about porcine anatomy we refer to Nickel et al. Vol. 1-511.

Basic Surgical Techniques in the G&amp;#246;ttingen Minipig: Intubation, Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion

The use of domestic and miniature pigs in science has increased significantly in recent years. By demonstrating how to perform intubation, transurethral bladder catheterization, femoral artery and vein catheterization, as well as transcardial perfusion, we aim to further increase the value of G&ouml;ttingen minipigs in biomedical research.

Técnicas de Cirugía Básica en el minipig Göttingen: intubación, cateterización de la vejiga, el cateterismo femoral del buque, y perfusión Transcardial

The emergence of the G&ouml;ttingen minipig in research of topics such as neuroscience, toxicology, diabetes, obesity, and experimental surgery reflects ...

Investigación

Medicina

Quantification of Atherosclerotic Plaque Activity and Vascular Inflammation using [18-F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT)

Conventional non-invasive imaging modalities of atherosclerosis such as coronary artery calcium (CAC)1 and carotid intimal medial thickness (C-IMT)2 provide information about the burden of disease. However, despite multiple validation studies of CAC3-5, and C-IMT2,6, these modalities do not accurately assess plaque characteristics7,8, and the composition and inflammatory state of the plaque determine its stability and, therefore, the risk of clinical events9-13.
[18F]-2-fluoro-2-deoxy-D-glucose (FDG) imaging using positron-emission tomography (PET)/computed tomography (CT) has been extensively studied in oncologic metabolism14,15. Studies using animal models and immunohistochemistry in humans show that FDG-PET/CT is exquisitely sensitive for detecting macrophage activity16, an important source of cellular inflammation in vessel walls. More recently, we17,18 and others have shown that FDG-PET/CT enables highly precise, novel measurements of inflammatory activity of activity of atherosclerotic plaques in large and medium-sized arteries9,16,19,20. FDG-PET/CT studies have many advantages over other imaging modalities: 1) high contrast resolution; 2) quantification of plaque volume and metabolic activity allowing for multi-modal atherosclerotic plaque quantification; 3) dynamic, real-time, in vivo imaging; 4) minimal operator dependence. Finally, vascular inflammation detected by FDG-PET/CT has been shown to predict cardiovascular (CV) events independent of traditional risk factors21,22 and is also highly associated with overall burden of atherosclerosis23. Plaque activity by FDG-PET/CT is modulated by known beneficial CV interventions such as short term (12 week) statin therapy24 as well as longer term therapeutic lifestyle changes (16 months)25.
The current methodology for quantification of FDG uptake in atherosclerotic plaque involves measurement of the standardized uptake value (SUV) of an artery of interest and of the venous blood pool in order to calculate a target to background ratio (TBR), which is calculated by dividing the arterial SUV by the venous blood pool SUV. This method has shown to represent a stable, reproducible phenotype over time, has a high sensitivity for detection of vascular inflammation, and also has high inter-and intra-reader reliability26. Here we present our methodology for patient preparation, image acquisition, and quantification of atherosclerotic plaque activity and vascular inflammation using SUV, TBR, and a global parameter called the metabolic volumetric product (MVP). These approaches may be applied to assess vascular inflammation in various study samples of interest in a consistent fashion as we have shown in several prior publications.9,20,27,28

Quantification of Atherosclerotic Plaque Activity and Vascular Inflammation using [18-F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography FDG-PET/CT

There is great need to identify atherosclerosis non-invasively, and here we demonstrate how FDG-PET/CT can be used to detect and quantify atherosclerotic plaque activity and vascular inflammation.

La cuantificación de la actividad de la placa aterosclerótica y la inflamación vascular utilizando [18-F] fluorodeoxiglucosa por emisión de positrones / tomografía computarizada (PET-TC)

Conventional non-invasive imaging modalities of atherosclerosis such as coronary artery calcium (CAC)1 and carotid intimal medial thickness (C-IMT)2 ...

Non-invasive Imaging and Analysis of Cerebral Ischemia in Living Rats Using Positron Emission Tomography with 18F-FDG

Stroke is the third leading cause of death among Americans 65 years of age or older1. The quality of life for patients who suffer from a stroke fails to return to normal in a large majority of patients2, which is mainly due to current lack of clinical treatment for acute stroke. This necessitates understanding the physiological effects of cerebral ischemia on brain tissue over time and is a major area of active research. Towards this end, experimental progress has been made using rats as a preclinical model for stroke, particularly, using non-invasive methods such as 18F-fluorodeoxyglucose (FDG) coupled with Positron Emission Tomography (PET) imaging3,10,17. Here we present a strategy for inducing cerebral ischemia in rats by middle cerebral artery occlusion (MCAO) that mimics focal cerebral ischemia in humans, and imaging its effects over 24 hr using FDG-PET coupled with X-ray computed tomography (CT) with an Albira PET-CT instrument. A VOI template atlas was subsequently fused to the cerebral rat data to enable a unbiased analysis of the brain and its sub-regions4. In addition, a method for 3D visualization of the FDG-PET-CT time course is presented. In summary, we present a detailed protocol for initiating, quantifying, and visualizing an induced ischemic stroke event in a living Sprague-Dawley rat in three dimensions using FDG-PET.

Non-invasive Imaging and Analysis of Cerebral Ischemia in Living Rats Using Positron Emission Tomography with 18F-FDG

Brain damage resulting from cerebral ischemia may be non-invasively imaged and studied in rats using pre-clinical positron emission tomography coupled with the injectable radioactive probe, 18F-fluorodeoxyglucose. Further, the use of modern software tools that include volume of interest (VOI) brain templates dramatically increase the quantitative information gleaned from these studies.

De imagen no invasivas y Análisis de la isquemia cerebral en ratas vivas utilizando Tomografía por emisión de positrones con<sup&gt; 18</sup&gt; F-FDG

Stroke is the third leading cause of death among Americans 65 years of age or older1. The quality of life for patients who suffer from a stroke fails to ...

Cerenkov Luminescence Imaging of Interscapular Brown Adipose Tissue

Brown adipose tissue (BAT), widely known as a &#8220;good fat&#8221; plays pivotal roles for thermogenesis in mammals. This special tissue is closely related to metabolism and energy expenditure, and its dysfunction is one important contributor for obesity and diabetes. Contrary to previous belief, recent PET/CT imaging studies indicated the BAT depots are still present in human adults. PET imaging clearly shows that BAT has considerably high uptake of 18F-FDG under certain conditions. In this video report, we demonstrate that Cerenkov luminescence imaging (CLI) with 18F-FDG can be used to optically image BAT in small animals. BAT activation is observed after intraperitoneal injection of norepinephrine (NE) and cold treatment, and depression of BAT is induced by long anesthesia. Using multiple-filter Cerenkov luminescence imaging, spectral unmixing and 3D imaging reconstruction are demonstrated. Our results suggest that CLI with 18F-FDG is a practical technique for imaging BAT in small animals, and this technique can be used as a cheap, fast, and alternative imaging tool for BAT research.

In this video report, we show the application of Cerenkov Luminescence Imaging (CLI) for interscapular brown adipose tissue in mice under activated and depressed conditions.

Cerenkov Luminiscencia Imaging de interescapular tejido adiposo marrón

Brown adipose tissue (BAT), widely known as a &#8220;good fat&#8221; plays pivotal roles for thermogenesis in mammals. This special tissue is closely ...

Localization, Identification, and Excision of Murine Adipose Depots

Obesity has increased dramatically in the last few decades and affects over one third of the adult US population. The economic effect of obesity in 2005 reached a staggering sum of $190.2 billion in direct medical costs alone. Obesity is a major risk factor for a wide host of diseases. Historically, little was known regarding adipose and its major and essential functions in the body. Brown and white adipose are the two main types of adipose but current literature has identified a new type of fat called brite or beige adipose. Research has shown that adipose depots have specific metabolic profiles and certain depots allow for a propensity for obesity and other related disorders. The goal of this protocol is to provide researchers the capacity to identify and excise adipose depots that will allow for the analysis of different factorial effects on adipose; as well as the beneficial or detrimental role adipose plays in disease and overall health. Isolation and excision of adipose depots allows investigators to look at gross morphological changes as well as histological changes. The adipose isolated can also be used for molecular studies to evaluate transcriptional and translational change or for in vitro experimentation to discover targets of interest and mechanisms of action. This technique is superior to other published techniques due to the design allowing for isolation of multiple depots with simplicity and minimal contamination.

Due to the drastic and negative connection between obesity and other comorbidities, research on the role adipose plays in disease and overall health is warranted. We present a protocol for the isolation and excision of adipose depots allowing for the study of adipose using in situ and in vitro methods.

Localización, identificación y Escisión de depósitos adiposos murino

Obesity has increased dramatically in the last few decades and affects over one third of the adult US population. The economic effect of obesity in 2005 ...

Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular weight metabolites in tissues of the treated host to achieve long-term survival. The semipermeable membrane allows engrafted encapsulated cells to avoid rejection by the immune system. The encapsulation procedure was designed to enable a controlled release of bioactive compounds, such as insulin, other hormones, and cytokines. Here we describe a method for encapsulation of catabolic cells, which consume lipids for heat production and energy dissipation (thermogenesis) in the intra-abdominal adipose tissue of obese mice. Encapsulation of thermogenic catabolic cells may be potentially applicable to the prevention and treatment of obesity and type 2 diabetes. Another potential application of catabolic cells may include detoxification from alcohols or other toxic metabolites and environmental pollutants.

Here, we present a protocol for encapsulation of catabolic cells, which consume lipids for heat production in intra-abdominal adipose tissue and increase energy dissipation in obese mice.

La encapsulación termogénico preadipocitos para el trasplante en los depósitos de tejido adiposo

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular ...

Assessment of Human Adipose Tissue Microvascular Function Using Videomicroscopy

While obesity is closely linked to the development of metabolic and cardiovascular disease, little is known about mechanisms that govern these processes. It is hypothesized that pro-atherogenic mediators released from fat tissues particularly in association with central/visceral adiposity may promote pathogenic vascular changes locally and systemically, and the notion that cardiovascular disease may be the consequence of adipose tissue dysfunction continues to evolve. Here, we describe a unique method of videomicroscopy that involves analysis of vasodilator and vasoconstrictor responses of intact small human arterioles removed from the adipose depot of living human subjects. Videomicroscopy is used to examine functional properties of isolated microvessels in response to pharmacological or physiological stimuli using a pressured system that mimics in vivo conditions. The technique is a useful approach to gain understanding of the pathophysiology and molecular mechanisms that contribute to vascular dysfunction locally within the adipose tissue milieu. Moreover, abnormalities in the adipose tissue microvasculature have also been linked with systemic diseases. We applied this technique to examine depot-specific vascular responses in obese subjects. We assessed endothelium-dependent vasodilation to both increased flow and acetylcholine in adipose arterioles (50 - 350 &#181;m internal diameter, 2 - 3 mm in length) isolated from two different adipose depots during bariatric surgery from the same individual. We demonstrated that arterioles from visceral fat exhibit impaired endothelium-dependent vasodilation compared to vessels isolated from the subcutaneous depot. The findings suggest that the visceral microenvironment is associated with vascular endothelial dysfunction which may be relevant to clinical observation linking increased visceral adiposity to systemic disease mechanisms. The videomicroscopy technique can be used to examine vascular phenotypes from different fat depots as well as compare findings across individuals with different degrees of obesity and metabolic dysfunction. The method can also be used to examine vascular responses longitudinally in response to clinical interventions.

Videomicroscopy systems are used to examine functional properties of isolated adipose tissue arterioles in response to physiological and pharmacological stimuli. This technique can be used to examine microvascular phenotypes in different adipose tissue domains in obese humans.

Evaluación de la función Microvascular del tejido adiposo humano mediante videomicroscopía

While obesity is closely linked to the development of metabolic and cardiovascular disease, little is known about mechanisms that govern these processes. ...

Characterization of Immune Cells in Human Adipose Tissue by Using Flow Cytometry

Infiltration of immune cells in the subcutaneous and visceral adipose tissue (AT) deposits leads to a low-grade inflammation contributing to the development of obesity-associated complications such as type 2 diabetes. To quantitatively and qualitatively investigate the immune cell subsets in human AT deposits, we have developed a flow cytometry approach. The stromal vascular fraction (SVF), containing the immune cells, is isolated from subcutaneous and visceral AT biopsies by collagenase digestion. Adipocytes are removed after centrifugation. The SVF cells are stained for multiple membrane-bound markers selected to differentiate between immune cell subsets and analyzed using flow cytometry. As a result of this approach, pro- and anti-inflammatory macrophage subsets, dendritic cells (DCs), B-cells, CD4+ and CD8+ T-cells, and NK cells can be detected and quantified. This method gives detailed information about immune cells in AT and the amount of each specific subset. Since there are numerous fluorescent antibodies available, our flow cytometry approach can be adjusted to measure various other cellular and intracellular markers of interest.

This article describes a method to analyze immune cell content of adipose tissue by isolation of immune cells from adipose tissue and subsequent analysis using flow cytometry.

Caracterización de células inmunes en el tejido adiposo humano mediante el uso de citometría de flujo

Infiltration of immune cells in the subcutaneous and visceral adipose tissue (AT) deposits leads to a low-grade inflammation contributing to the ...

Whole Body and Regional Quantification of Active Human Brown Adipose Tissue Using 18F-FDG PET/CT

In endothermic animals, brown adipose tissue (BAT) is activated to produce heat for defending body temperature in response to cold. BAT&#39;s ability to expend energy has made it a potential target for novel therapies to ameliorate obesity and associated metabolic disorders in humans. Though this tissue has been well studied in small animals, BAT&#39;s thermogenic capacity in humans remains largely unknown due to the difficulties of measuring its volume, activity, and distribution. Identifying and quantifying active human BAT is commonly performed using 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography and computed tomography (PET/CT) scans following cold-exposure or pharmacological activation. Here we describe a detailed image-analysis approach to quantify total-body human BAT from 18F-FDG PET/CT scans using an open-source software. We demonstrate the drawing of user-specified regions of interest to identify metabolically active adipose tissue while avoiding common non-BAT tissues, to measure BAT volume and activity, and to further characterize its anatomical distribution. Although this rigorous approach is time-consuming, we believe it will ultimately provide a foundation to develop future automated BAT quantification algorithms.

Whole Body and Regional Quantification of Active Human Brown Adipose Tissue Using 18F-FDG PET/CT

Using free, open-source software, we have developed an analytical approach to quantify total and regional brown adipose tissue (BAT) volume and metabolic activity of BAT using 18F-FDG PET/CT.

Cuerpo entero y cuantificación Regional de activo humano marrón tejido adiposo utilizando 18F-FDG PET/CT

In endothermic animals, brown adipose tissue (BAT) is activated to produce heat for defending body temperature in response to cold. BAT&#39;s ability to ...

Continuous Blood Sampling in Small Animal Positron Emission Tomography/Computed Tomography Enables the Measurement of the Arterial Input Function

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal blood time-activity concentration also known as arterial input function (AIF) is a key point, especially for the characterization of animal disease models and the introduction of newly developed radiotracers. The knowledge of radiotracer availability in the blood helps to interpret PET/CT-derived data of tissue activity. For this purpose, online blood sampling during the PET/CT imaging is advisable to measure the AIF. In contrast to manual blood sampling and image-derived approaches, continuous online blood sampling has several advantages. Besides the minimized blood loss, there is an improved resolution and a superior accuracy for the blood activity measurement. However, the major drawback of online blood sampling is the costly and time-consuming preparation to catheterize the femoral vessels of the animal. Here, we describe an easy and complete workflow for catheterization and continuous blood sampling during small animal PET/CT imaging and compared it to manual blood sampling and an image-derived approach. Using this highly-standardized workflow, the determination of the fluorodeoxyglucose ([18F]FDG) AIF is demonstrated. Further, this procedure can be applied to any radiotracer in combination with different animal models to create fundamental knowledge of tracer kinetic and model characteristics. This allows a more precise evaluation of the behavior of pharmaceuticals, both for diagnostic and therapeutic approaches in the preclinical research of oncological, neurodegenerative and myocardial diseases.

Here a protocol for continuous blood sampling during PET/CT imaging of rats to measure the arterial input function (AIF) is described. The catheterization, the calibration and setup of the system and the data analysis of the blood radioactivity are demonstrated. The generated data provide input parameters for subsequent bio-kinetic modeling.

El muestreo sanguíneo continuo en tomografía por emisión de positrones de animales pequeños permite la medición de la función de entrada arterial

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal ...