ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

We thank the support of National Natural Science Foundation of China (NSFC) - Excellent Young Scientists Fund (Hong Kong and Macau) (81922079), Hong Kong Research Grants Council General Research Fund (GRF 17121520 and 17123419), and Hong Kong Research Grants Council Collaborative Research Fund (CRF C7018-14E) for small animal imaging experiments.

The protocol described below follows the animal care guidelines of The University of Hong Kong. The animals used in the study were 8-week-old C57BL/6J mice.
1. Animal surgical procedures and cold challenge
<ol>
	<li>Perform interscapular BAT (iBAT) dissection.
	<ol>
		<li>Anesthetize the mice by intraperitoneal injection of ketamine/xylazine (100 mg/kg bodyweight ketamine and 10 mg/kg bodyweight xylazine). After anesthesia, shave the hair of the mouse from the neck to just below the scapulae.</li>
		<li>Place the mice on the heating pad after disinfection and make a 2 cm incision along the dorsal midline of the mice.</li>
		<li>Remove the iBAT pads (bilateral). In the sham-operated group, make the same incision but leave the iBAT pads intact.</li>
		<li>Close the incision using 7 mm stainless steel wound clips after the bleeding stops.</li>
		<li>After surgery, give meloxicam (5 mg/kg in drinking water) to the mice for 6 days and house them in an intensive care unit (ICU) for 14 days. Remove the clips as soon as the wound is healed (7-10 days).</li>
	</ol>
	</li>
	<li>Cold challenge of the mice: House the mice at thermoneutrality (30 &#176;C) for 14 days. On day 13, pre-chill the animal cages in cold (6 &#176;C) overnight. On day 14, put the mice at 6 &#176;C in the environmental chamber for 7 days. Place two mice in each cage.</li>
</ol>
2. Micro-PET/MR calibrations and workflow setup
NOTE: Micro-PET/MR imaging is performed using a sequential PET/MR system (see Table of Materials). Each mouse is placed on the imaging bed; first scan with the MR for an anatomical reference (scout view) before advancing to the center of the PET field-of-view (FOV) for a static [18F]FDG PET acquisition, followed by MR imaging for anatomic reference. An imaging workflow is created in the scanner-operating software (see Table of Materials) to enable automated, sequential PET/MR scans prior to the imaging session.
<ol>
	<li>Create an imaging workflow in the operating software that includes static PET acquisition, MRI acquisitions for attenuation correction, and anatomical reference using T1-weigthed 3D imaging and T2-weighted 2D imaging, respectively.</li>
	<li>To acquire PET, set 400-600 keV level discrimination, F-18 study isotope, 1-5 coincidence mode and 20 min scans.</li>
	<li>To acquire T1-weighted MR (for attenuation correction), set Gradient Echo-3D (TE = 4.3 ms, TR = 16 ms, FOV = 90 x 60 mm, number of excitations (NEX) = 3, 28 slices with 0.9 mm thickness, voxel size = 0.375 x 0.375 x 0.9 mm).</li>
	<li>To acquire T2-weighted MR (anatomical reference), set Fast-spin Echo 2D (TE = 71.8 ms, TR = 3000 ms, FOV = 90 x 60 mm, NEX = 5, 32 slices with 0.9 mm thickness, voxel size = 0.265 x 0.268 x 0.9 mm3).</li>
	<li>To reconstruct PET, use Tera-Tomo 3D (TT3D) algorithm (8 iterations, 6 subsets) with 1-3 coincidence mode, and with decay, dead-time, random, attenuation, and scatter corrections to create images with an overall of 0.3 mm3 voxel size.</li>
	<li>Perform a PET Activity Test of the micro-PET/MR scanner one day before the start of imaging study to check the accuracy of PET quantitation.
	<ol>
		<li>Prepare a 5 mL syringe filled with [18F]FDG as recommended by the manufacturer guidelines (140-220 &#956;Ci/5-8 MBq in water or saline).</li>
		<li>Record the activity of the syringe using a dose calibrator (see Table of Materials) and note the time of measurement.</li>
		<li>Select Interpolated Ellipse ROI to draw a volume-of-interest (VOI) on the reconstructed image to compare the recovered activity to the value measured as described above. The recovered activity for a well-calibrated scanner is accurate within &#177;5%.</li>
	</ol>
	</li>
</ol>
3. Injection of [18F]FDG
<ol>
	<li>Order a clinical dose of [18F]FDG (10 mCi/370 MBq) from the supplier for its arrival to the imaging lab approximately 30 min before the first scheduled injection. Make sure to wear appropriate personal protective equipment (PPE), such as a lab coat, gloves, personal radiation dosimeter e.g. Fingers, whole body when receiving the package containing radioactive materials. Change gloves regularly to prevent cross contamination of the radioactivity and increase distance from the radioactive source as much as possible.</li>
	<li>Use the forceps to carefully transfer the [18F]FDG stock vial behind an L-block table top shield.</li>
	<li>Dispense an aliquot of [18F]FDG and dilute with sterilized saline to give a total activity concentration at 200-250 &#956;Ci/7-9 MBq) in 100-150 &#956;L.</li>
	<li>Draw the [18F]FDG solution into a 1 mL syringe with needle (see Table of Materials), measure the radioactivity using a dose calibrator set to F-18, and record the time of measurement.</li>
	<li>Record the weight of the mouse prior to injection. Inject the prepared [18F]FDG solution via tail vein. Take note of the injection time and residue of the radioactivity of the syringe to enable decay correction.</li>
	<li>Put the mouse back in the cage and allow [18F]FDG uptake for 60 min before PET scans.</li>
	<li>Calculate the injected [18F]FDG activity using the following formula11: 
	Injected activity (&#956;Ci/MBq) 
	= Activity in the syringe before injection 
	- activity in the syringe after injection</li>
</ol>
4. Micro-PET/MR acquisition
<ol>
	<li>Turn on the air heater to the mouse bed to allow warm air to pass through it.</li>
	<li>Anesthetize the mouse using 5% isoflurane (1 L/min medical O2). Once induced, transfer the mouse to the warm mouse bed and maintain anesthesia at 2%-3 % isoflurane via a nose mask cone. Position the mouse head-prone onto the bite bar and make sure the mouse does not protrude outside of the diameter of the bed. Apply eye lubricant to avoid drying and formation of corneal ulcers.</li>
	<li>Monitor the body temperature and the respiratory rate by a thermal probe and a respiratory pad, respectively. Maintain the body temperature at 36-37 &#176;C, and the respiratory rate at 70-80 breaths per minute (bpm) by adjusting the isoflurane level.</li>
	<li>Perform a scout view to determine the mouse position. Adjust the mouse bed position to include the whole mouse body, and to ensure the center FOV of MR is in the center of mouse body.</li>
	<li>Under the PET Acquisition in the study list window, select Scan Range on Previous Acquisition to use the scout view position as described above. Click on Prepare to move the animal bed from MR to PET. Select OK to initiate the PET scan. Record the injection dose and time measured before and after [18F]FDG administration in the Radiopharmaceutical Editor. Enter the weight of the mouse under the Subject Information menu.</li>
	<li>Once the PET scan is completed, select Prepare to move to MR and complete all the MR acquisitions in the study list window. Select OK to start the MR scans.</li>
	<li>After the whole workflow is completed, briefly evaluate the quality of the acquired MR images using the post-processing software (see Table of Materials). Click on the Home button to move the mouse bed from MR to the original position.</li>
	<li>Carefully remove the mouse from the scanner and return it to a clean housing cage with a heated pad underneath to allow recovery in warm environment. Supply the mouse with food and water. The system is now ready for the next mouse in queue.</li>
	<li>To reconstruct data, select PET Acquisition under the Raw Scan menu to load the completed PET scan. Select T1-weighted MR Acquisition for material map creation. Reconstruct the data as described above (see step 2.5).</li>
	<li>Follow the local and institute regulations regarding the care and handling of post-PET imaging mouse. Consider all used syringes/needles, gloves, bedding, and fecal matter as radioactive waste that require special handling/disposal in accordance with the local regulations.</li>
</ol>
5. Post-imaging analysis
<ol>
	<li>Open the Image Analysis software (see Table of Materials) and click on Load DICOM Data to retrieve the corresponding MR and PET images.</li>
	<li>Perform co-registration of MR and PET image by dragging these images to the display window. Click on the Automatic Registration function.
	<ol>
		<li>Select Rigid transformation under the Registration Setup drop-down menu. Check Shift and Rotation under the Rigid/Affine menu.</li>
		<li>Select T1-weighted MR acquisition as the Reference and PET acquisition as the Reslice under the Global Role Selection menu.</li>
		<li>Inspect the registration in all three dimensions to make sure a perfect alignment between MR and PET images. To adjust it manually, click on Manual Registration.</li>
	</ol>
	</li>
	<li>Use Interpolated Ellipse ROI to draw VOI on the tissue of interest, i.e., iBAT and inguinal white adipose tissue (iWAT) using MR image for reference. Use the Brush Tool and Eraser Tool to define the VOI border; hence, the anatomy of tissues. Make sure there is no overlap uptake by using PET image to avoid spillover from the neighboring organs. Repeat the process slide-by-slide until the whole VOI is delineated. If necessary, edit the VOIs to maintain consistent VOI volumes between each mouse.</li>
	<li>Use Ellipsoid VOI to draw a 3 mm3 VOI on the lung as a reference organ. Avoid any spillover from the neighboring heart and muscle.</li>
	<li>Upon completion, click on Show ROI Table to rename each VOI. Record the mean radioactivity with the VOI and tissue volume into a spreadsheet. Archive the VOI drawings and the imaging data to a data storage device.</li>
	<li>Calculate the standardized uptake value (SUV) for all VOIs using the following equation11: 
	SUVmean&#160;= VOI radioactivity in kBq / (Decay - corrected injected dose in kBq / mouse body weight in kg), assuming a tissue density of 1 g/mL.&#160;</li>
</ol>

<ol><li>Rosen, E. D., Spiegelman, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((What+we+talk+about+when+we+talk+about+fat%5BTitle%5D)+AND+%22Cell%22%5BJournal%5D)">What we talk about when we talk about fat.</a> Cell. 156 (1-2), 20-44 (2014).</li>
<li>Cannon, B., Brown Nedergaard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((adipose+tissue%3A+function+and+physiological+significance%5BTitle%5D)+AND+%22Physiological+Review%22%5BJournal%5D)">adipose tissue: function and physiological significance.</a> Physiological Review. 84 (1), 277-359 (2004).</li>
<li>Jal Wu,, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Beige+adipocytes+are+a+distinct+type+of+thermogenic+fat+cell+in+mouse+and%5BTitle%5D)+AND+%22%22%5BJournal%5D)">Beige adipocytes are a distinct type of thermogenic fat cell in mouse and.</a> 150 (2), 366-376 (2012).</li>
<li>Cypess, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Activation+of+human+brown+adipose+tissue+by+a+beta3-adrenergic+receptor+agonist%5BTitle%5D)+AND+%22Cell+Metabolism%22%5BJournal%5D)">Activation of human brown adipose tissue by a beta3-adrenergic receptor agonist.</a> Cell Metabolism. 21 (1), 33-38 (2015).</li>
<li>Ishibashi, J., Seale, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Beige+can+be+slimming%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Beige can be slimming.</a> Science. 328 (5982), 1113-1114 (2010).</li>
<li>Jal Schulz, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Brown-fat+paucity+due+to+impaired+BMP+signalling+induces+compensatory+browning+of+white+fat%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Brown-fat paucity due to impaired BMP signalling induces compensatory browning of white fat.</a> Nature. 495 (7441), 379-383 (2013).</li>
<li>Pal Cohen,, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Ablation+of+PRDM16+and+beige+adipose+causes+metabolic+dysfunction+and+a+subcutaneous+to+visceral+fat+switch%5BTitle%5D)+AND+%22Cell%22%5BJournal%5D)">Ablation of PRDM16 and beige adipose causes metabolic dysfunction and a subcutaneous to visceral fat switch.</a> Cell. 156 (1-2), 304-316 (2014).</li>
<li>Mal Cypess, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Identification+and+importance+of+brown+adipose+tissue+in+adult+humans%5BTitle%5D)+AND+%22New+England+Journal+of+Medicine%22%5BJournal%5D)">Identification and importance of brown adipose tissue in adult humans.</a> New England Journal of Medicine. 360 (15), 1509-1517 (2009).</li>
<li>Aal vander Lans, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Cold+acclimation+recruits+human+brown+fat+and+increases+nonshivering+thermogenesis%5BTitle%5D)+AND+%22Journal+of+Clinical+Investigation%22%5BJournal%5D)">Cold acclimation recruits human brown fat and increases nonshivering thermogenesis.</a> Journal of Clinical Investigation. 123 (8), 3395-3403 (2013).</li>
<li>Jal Hanssen, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Short-term+cold+acclimation+improves+insulin+sensitivity+in+patients+with+type+2+diabetes+mellitus%5BTitle%5D)+AND+%22Nature+Medicine%22%5BJournal%5D)">Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus.</a> Nature Medicine. 21 (8), 863-865 (2015).</li>
<li>Wang, X., Minze, L. J., Shi, Z. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Functional+imaging+of+brown+fat+in+mice+with+18F-FDG+micro-PET%2FCT%5BTitle%5D)+AND+%22Journal+of+Visualized+Experiments%3A+JoVE%22%5BJournal%5D)">Functional imaging of brown fat in mice with 18F-FDG micro-PET/CT.</a> Journal of Visualized Experiments: JoVE. 69, (2012).</li>
<li>Greenwood, H. E., Nyitrai, Z., Mocsai, G., Hobor, S., Witney, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((High-throughput+PET%2FCT+imaging+using+a+multiple-mouse+imaging+system%5BTitle%5D)+AND+%22Journal+of+Nuclear+Medicine%3A+Official+Publication%2C+Scoiety+of+Nuclear+Medicine%22%5BJournal%5D)">High-throughput PET/CT imaging using a multiple-mouse imaging system.</a> Journal of Nuclear Medicine: Official Publication, Scoiety of Nuclear Medicine. 61 (2), 292-297 (2020).</li>
<li>Carter, L. M., Henry, K. E., Platzman, A., Lewis, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((3D-printable+platform+for+high-throughput+small-animal+imaging%5BTitle%5D)+AND+%22Journal+of+Nuclear+Medicine%3A+Official+Publication%2C+Scoiety+of+Nuclear+Medicine%22%5BJournal%5D)">3D-printable platform for high-throughput small-animal imaging.</a> Journal of Nuclear Medicine: Official Publication, Scoiety of Nuclear Medicine. 61 (11), 1691-1692 (2020).</li>
<li>Jal Andersson,, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Estimating+the+cold-induced+brown+adipose+tissue+glucose+uptake+rate+measured+by+%2818%29F-FDG+PET+using+infrared+thermography+and+water-fat+separated+MRI%5BTitle%5D)+AND+%22Scientific+Reports%22%5BJournal%5D)">Estimating the cold-induced brown adipose tissue glucose uptake rate measured by (18)F-FDG PET using infrared thermography and water-fat separated MRI.</a> Scientific Reports. 9 (18), 12358(2019).</li>
<li>Eal Lundstrom,, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Brown+adipose+tissue+estimated+with+the+magnetic+resonance+imaging+fat+fraction+is+associated+with+glucose+metabolism+in+adolescents%5BTitle%5D)+AND+%22Pediatric+Obesity%22%5BJournal%5D)">Brown adipose tissue estimated with the magnetic resonance imaging fat fraction is associated with glucose metabolism in adolescents.</a> Pediatric Obesity. 14 (9), (2019).</li>
<li>Eal Lundstrom,, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Magnetic+resonance+imaging+cooling-reheating+protocol+indicates+decreased+fat+fraction+via+lipid+consumption+in+suspected+brown+adipose+tissue%5BTitle%5D)+AND+%22PLoS+One%22%5BJournal%5D)">Magnetic resonance imaging cooling-reheating protocol indicates decreased fat fraction via lipid consumption in suspected brown adipose tissue.</a> PLoS One. 10 (4), 0126705(2015).</li>
<li>Nakamura, Y., Yanagawa, Y., Morrison, S. F., Nakamura, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Medullary+reticular+neurons+mediate+neuropeptide+Y-induced+metabolic+inhibition+and+mastication%5BTitle%5D)+AND+%22Cell+Metabolism%22%5BJournal%5D)">Medullary reticular neurons mediate neuropeptide Y-induced metabolic inhibition and mastication.</a> Cell Metabolism. 25 (2), 322-334 (2017).</li>
<li>Jal Fueger, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Impact+of+animal+handling+on+the+results+of+18F-FDG+PET+studies+in+mice%5BTitle%5D)+AND+%22Journal+of+Nuclear+Medicine%3A+Official+Publication%2C+Scoiety+of+Nuclear+Medicine%22%5BJournal%5D)">Impact of animal handling on the results of 18F-FDG PET studies in mice.</a> Journal of Nuclear Medicine: Official Publication, Scoiety of Nuclear Medicine. 47 (6), 999-1006 (2006).</li>
<li>Vines, D. C., Green, D. E., Kudo, G., Keller, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Evaluation+of+mouse+tail-vein+injections+both+qualitatively+and+quantitatively+on+small-animal+PET+tail+scans%5BTitle%5D)+AND+%22Journal+of+Nuclear+Medicine+Technology%22%5BJournal%5D)">Evaluation of mouse tail-vein injections both qualitatively and quantitatively on small-animal PET tail scans.</a> Journal of Nuclear Medicine Technology. 39 (4), 264-270 (2011).</li>
</ol>

The authors have no conflicts of interest to disclose.

In this study, a PET/MR -based imaging and quantification of functional brown and beige adipose tissue in small animal was described. This method uses the non-metabolizable glucose analog [18F]FDG as an imaging biomarker so as to identify the adipose tissues with high glucose-demand in a non-invasive manner. MR offers good soft tissue contrast and can better differentiate adipose fat tissues from the neighboring soft tissues and muscle. When combined with PET, this enables imaging and quantifying of the activa...

In response to changing nutritional needs, adipose tissue serves as an energy cache to adopt either lipid storage or mobilization mode to meet the needs of the body1. Moreover, adipose tissue also plays a key function in thermoregulation, via a process called non-shivering thermogenesis, also called facultative thermogenesis. This is typically achieved by the brown adipose tissue (BAT), which expresses abundant level of mitochondria membrane protein uncoupling protein 1 (UCP1). As a proton carrier, UCP1 generates heat by uncoupling the proton transport and ATP production2. Upon cold stimulation, thermogenesis in BAT is set in motion by activation of the sympathetic nervous system (SNS), followed by release of norepinephrine (NE). NE binds to the &#946;3 adrenergic receptors and leads to elevation of intracellular cyclic AMP (cAMP). As a consequence, cAMP/PKA-dependent engagement of CREB (cAMP response element-binding protein) stimulates Ucp1 transcription via direct binding on CREB-response elements (CRE)2. In addition to BAT, brown-like adipocytes are also found within white adipose tissue and are therefore named beige or brite (brown-in-white) cells1,3. In response to specific stimuli (such as cold), these otherwise quiescent beige cells are remodeled to exhibit multiple brown-like features, including multilocular lipid droplets, densely-packed mitochondria, and augmented UCP1 expression3,4,5.
Animal studies have demonstrated that brown and beige adipocytes possess multiple metabolic benefits beyond its fat-reducing effect, including insulin-sensitization, lipid-lowering, anti-inflammation, and anti-atherosclerosis6,7. In humans, the amount of beige/brown fat is inversely correlated with age, insulin resistance index, and cardiometabolic disorders8. Moreover, activation of beige/brown adipocytes in humans by either cold acclimation or &#946;3 adrenergic receptor agonist confers protection against a series of metabolic disorders4,9,10. These pieces of evidence collectively indicate that induction of brown and beige adipose tissue is a potential therapeutic strategy for management of obesity and its related medical complications8.
Interestingly, although they share similar function, beige and classical brown adipocytes are derived from different precursors and activated by overlapping but distinct mechanisms1. Therefore, in vivo imaging and quantification of brown and beige adipocytes are essential to achieve a better understanding of the molecular control of these adipose tissues. Currently 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) scan combined with computed tomography (CT) remains the gold standard for characterization of thermogenic brown and beige cells in clinical studies8. Magnetic resonance imaging (MRI) uses powerful magnetic fields and radio frequency pulses to produce detailed anatomical structures. Compared to CT scan, MRI generates images of organs and soft tissues with a higher resolution. Provided here is a protocol for visualization and quantification of functional brown and beige adiposes in mouse models after acclimation to cold exposure, a common and most reliable way to induce adipose browning. This method can be applied to characterize the thermogenic adipose depots in small animal models with high precision.

<table><tbody><tr><td>0.9% sterile saline</td><td>BBraun</td><td></td><td>0.9% sodium chloride intravenous infusion, 500 mL</td></tr><tr><td>5 mL syringe</td><td>Terumo</td><td>SS05L</td><td>5 mL syringe Luer Lock</td></tr><tr><td>Dose Calibrator</td><td>Biodex</td><td></td><td>Atomlab 500</td></tr><tr><td>Eye lubricant</td><td>Alcon Duratears</td><td></td><td>Sterile ocular lubricant ointment, 3.5 g</td></tr><tr><td>Insulin syringe</td><td>Terumo</td><td>10ME2913</td><td>1 mL insulin syringe with needle</td></tr><tr><td>InterView Fusion software</td><td>Mediso</td><td>Version 3.03</td><td>Post-processing and image analysis software</td></tr><tr><td>Isoflurane</td><td>Chanelle Pharma</td><td></td><td>Iso-Vet, inhalation anesthetic, 250 mL</td></tr><tr><td>Ketamine</td><td>Alfasan International B.V.</td><td>HK-37715</td><td>Ketamine 10% injection solution, 10 mL</td></tr><tr><td>Medical oxygen</td><td>Linde HKO</td><td>101-HR</td><td>compressed gas, 99.5% purity</td></tr><tr><td>Metacam</td><td>Boehringer Ingelheim</td><td></td><td>5 mg/mL Meloxicam solution for injection for dogs and cats, 10 mL</td></tr><tr><td>nanoScan PET/MR Scanner</td><td>Mediso</td><td></td><td>3 Tesla MR</td></tr><tr><td>Nucline nanoScan software</td><td>Mediso</td><td>Version 3.0</td><td>Scanner operating software</td></tr><tr><td>Wound clips</td><td>Reflex 7</td><td>203-100</td><td>7mm Stainless steel wound clips, 20 clips</td></tr><tr><td>Xylazine</td><td>Alfasan International B.V.</td><td>HK-56179</td><td>Xylazine 2% injection solution, 30 mL</td></tr></tbody></table>

visualization and quantification of brown and beige adipose tissues in mice using [18f]fdg micro-pet/mr imaging

Visualization and Quantification of Brown and Beige Adipose Tissues in Mice using [18F]FDG Micro-PET/MR Imaging

Brown and beige adipocytes are now recognized as potential therapeutic targets for obesity and metabolic syndromes. Non-invasive molecular imaging methods are essential to provide critical insights into these thermogenic adipose depots. Here, the protocol presents a PET/MR imaging-based method to evaluate the activity of brown and beige adipocytes in mouse interscapular brown adipose tissue (iBAT) and inguinal subcutaneous white adipose tissue (iWAT). Visualization and quantification of the thermogenic adipose depots were achieved using [18F]FDG, the non-metabolizable glucose analog, as the radiotracer, when combined with the precise anatomical information provided by MR imaging. The PET/MR imaging was conducted 7 days after cold acclimation and quantitation of [18F]FDG signal in different adipose depots was conducted to assess the relative mobilization of thermogenic adipose tissues. Removal of iBAT substantially increased cold-evoked [18F]FDG uptake in iWAT of the mice.

Three groups of mice (n = 3 per group) underwent micro-PET/MR imaging in this study, where they were housed at either thermoneutrality (30 °C) or cold (6 °C) for 7 days. One group of mice (n = 3) had their iBAT removed (iBATx) prior to cold treatment (Figure 1A). This method led to an alteration to the white adipose tissue activity in all three mice. In particular, a remarkable increase in [18F]FDG uptake was observed in iWAT using micro-PET/MR imaging (Figure...

Functional imaging and quantitation of thermogenic adipose depots in mice using a micro-PET/MR imaging-based approach.

Brown and beige adipocytes are now recognized as potential therapeutic targets for obesity and metabolic syndromes. Non-invasive molecular imaging methods ...

visualization-quantification-brown-beige-adipose-tissues-mice-using

Research

JoVE Journal

Biology

Fat content analysis is routinely conducted in studies utilizing murine obesity models.  Emerging methods in small animal CT imaging and analysis are providing for longitudinal detail rich fat content analysis.  Here we detail step by step procedures for performing small animal CT imaging, analysis, and visualization.

Segmentation and Measurement of Fat Volumes in Murine Obesity Models Using X-ray Computed Tomography

A method of functional imaging of mouse brown adipose tissue (BAT) is described in which cold-stimulated uptake of 18F-Fluorodeoxyglucose (FDG) in BAT is non-invasively assessed with a standardized micro-PET/CT protocol. This method is robust and sensitive to detect differences in BAT activities in mouse models.

Functional Imaging of Brown Fat in Mice with 18F-FDG micro-PET/CT

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 Luminescence Imaging of Interscapular Brown Adipose Tissue

The method presented here uses 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET-CT) and fat-water separated magnetic resonance imaging (MRI), each scanned following 2 hr exposure to thermoneutral (24 °C) and cold conditions (17 °C) in order to map brown adipose tissue (BAT) in adult human subjects.

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

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.

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

Here, we present a protocol for measuring brown adipose tissue activity after a meal in humans and laboratory animals.

Infrared Thermography for the Detection of Changes in Brown Adipose Tissue Activity

Preadipocytes are isolated from the stromal vascular fraction of interscapular brown adipose tissue from newborn mice and differentiated into cells that accumulate lipid droplets, express molecular markers, and show the mitochondrial morphology of mature brown adipocytes. These cells are further analyzed by immunofluorescence and transmission electron microscopy.

Differentiation and Imaging of Brown Adipocytes from the Stromal Vascular Fraction of Interscapular Adipose Tissue from Newborn Mice

The analytical ultracentrifuge (AUC) sample cell holds sample and reference buffer and during experiments and is exposed to high vacuum and rotor speeds up to 60,000 rpm.  This video will demonstrate the rigorous attention to detail necessary for assembly, loading and alignment of this very important component of an AUC experiment.

Assembly, Loading, and Alignment of an Analytical Ultracentrifuge Sample Cell

Primary white preadipocytes isolated from white adipose tissues in mice can be differentiated into beige/brite cells. Presented here is a reliable cellular model system to study the molecular regulation of "browning" of white fat.

Isolation and Differentiation of Stromal Vascular Cells to Beige/Brite Cells

Traditional methods of assessing adipogenic differentiation are cheap and easy to use, but are not specific to changes in gene expression. We have developed an assay to quantify mesenchymal cell differentiation into mature adipocytes using a lineage specific marker. This assay has diverse applications across basic research and clinical medicine.

Visualization and Quantification of Mesenchymal Cell Adipogenic Differentiation Potential with a Lineage Specific Marker

Learn to visualize and quantify brown and beige adipose tissues in mice using [18F]FDG micro-PET/MR imaging. This protocol enables assessment of thermogenic adipocyte activity following cold acclimation and surgical manipulation.

Visualization and Quantification of Brown and Beige Adipose Tissues in Mice using [¹⁸F]FDG Micro-PET/MR Imaging

Explore More Videos