The authors would like to acknowledge Eliana Beraldi for performing viral transduction of tumor cell lines and Ben Deeley for his instruction on use of the small animal ultrasound imaging platform.
This project was supported by the German Foundation System (DFG; JA 2117/1&#8211;1:1), the Canadian Cancer Society Research Institute and a Mentored Physician Scientist Award from Vancouver Coastal Health Research Institute. The ultrasound imaging platform was funded by the Canadian Foundation for Innovation.

All animal procedures were performed according to the guidelines of the Canadian Council on Animal Care (CCAC). The protocol was approved by the Animal Care Committee of the University of British Columbia (Protocol Number: A10-0192).
1. Preparation of Cell Lines
<ol>
	<li>Confirm the identity of the respective human bladder cancer cell lines by DNA fingerprinting7.</li>
	<li>For growth analysis of xenograft tumors by bioluminescence, transfect cell lines with a lentiviral construct carrying the firefly luciferase gene3.</li>
	<li>Thaw and expand the existing cell lines in Dulbecco&#8217;s modified Eagle&#8217;s medium (DMEM) with 10% fetal bovine serum (FBS) at 37 &#176;C in a humidified 5% CO2 atmosphere. Passage the cells at least 3x but avoid culture times exceeding 3 months.</li>
</ol>
2. Preparation of Cell Suspension
<ol>
	<li>Thaw Matrigel. Keep the temperature below 4 &#176;C to avoid increased viscosity of the gel.</li>
	<li>Trypsinize the cells at a confluence of 70% and suspend in normal growth media.</li>
	<li>Count the cell number with a hemocytometer or automatic cell counter.</li>
	<li>Spin the cell suspension for 5 min at 200 x g. Remove the supernatant.</li>
	<li>Add the appropriate volume of DMEM (10% FBS) and Matrigel (1:1 ratio) in order to reach the desired cell concentration which is dependent on the utilized cell line and desired growth kinetics (8-15 x 106/ml). The injected volume of tumor cell suspension will be 40 &#181;l.</li>
	<li>Mix well by pipetting up and down (P1000), avoid creating air bubbles in the suspension.</li>
</ol>
3. Preparation of Animals
Note: Due to the potential need for transurethral catheterization in step 4.7, female mice are the preferred gender in this animal model.
<ol>
	<li>House mice according to institutional and national animal care guidelines. Obtain ethics committee approval for all experiments involving mice.</li>
	<li>Anesthetize the mice with 3% isoflurane/oxygen mixture. Confirm proper anesthetization of animals (e.g. unresponsiveness to toe pinches).</li>
</ol>
4. Experimental Setup
<ol>
	<li>Cut the bladder stabilization from any kind of flat rigid plastic material [Figure&#160;2 I]. Carefully inspect the strap and remove any sharp edges before application to the mice.</li>
	<li>Mount the animal on the heated imaging table [Figure&#160;1 I] of the small animal imaging platform with continuous monitoring of vital signs. Fix the lower limbs with a rubber band [Figure&#160;1 III].</li>
	<li>Disinfect the abdomen with 2% chlorhexidine gluconate and wipe the skin with a sterile cotton tip.</li>
	<li>Immobilize the bladder with the bladder stabilization strap [Figure&#160;2 II]. Thus, an evasion of the bladder during intramural injection in step 5.6 will be avoided.</li>
	<li>Apply sterile ultrasound gel to the lower abdomen.</li>
	<li>Slowly approach the ultrasound scanhead (frequency 40 MHz) [Figure&#160;1 IV] to the skin (longitudinal with a cranial angle of 45-70&#176;) and visualize the bladder on the ultrasound screen [Figure&#160;3 I].</li>
	<li>If the bladder is empty, fill it with 50 &#181;l&#160;sterile, warm phosphate-buffered saline (PBS) through a transurethral 24 G&#160;angiocatheter.</li>
</ol>
5. Separation of Bladder Wall Layers
<ol>
	<li>Attach a 1.0 ml&#160;syringe filled with PBS and connected to a 30 G, &#190; in needle (bevel directed anteriorly) to the syringe clamp.</li>
	<li>Position the needle towards the skin just above the pubic bone in a 30-45&#176; angle (80-90&#176; relative to the longitudinal axis of the ultrasound scanhead [Figure&#160;1]).</li>
	<li>Detect the needle on the ultrasound screen.</li>
	<li>Slowly perforate the skin and the abdominal wall muscles [Figure&#160;3 II].</li>
	<li>Turn the bevel of the needle 180&#176; (now directed posteriorly).</li>
	<li>Insert the tip of the needle into the bladder wall without penetrating the mucosa [Figure&#160;3 III]</li>
	<li>Slowly inject 50 &#181;l of PBS between the muscular layer and the mucosa in order to create an artificial space [Figure&#160;3 IV]. 
	Note: If the mucosa is accidently perforated during step 5.6, slowly pull back the needle and inject 50 &#181;l of PBS after the mucosal layer has flipped back over the needle tip.</li>
	<li>Withdraw the needle.</li>
</ol>
6. Intramural Inoculation of Bladder Cancer Cells
<ol>
	<li>Attach a second 1.0 ml&#160;syringe (filled with cancer cells suspended in Matrigel) with a 30 G, &#190; in needle to the syringe clamp.</li>
	<li>Guide the tip of the needle to the same PBS-filled space which was created in step 5.7.</li>
	<li>Inject 40 &#181;l&#160;of the cell suspension into this space [Figures&#160;3 V and&#160;VI].</li>
	<li>Withdraw the needle.</li>
</ol>
7. Post-interventional Supportive Care
<ol>
	<li>Dismount the mouse from the imaging platform.</li>
	<li>Keep the animal in a warm and comfortable environment under continuous surveillance while recovering from the anesthetic.</li>
	<li>After regaining consciousness and resuming normal ambulation, place the animal back in its home cage.</li>
</ol>

<ol>
	<li>Chan, E., Patel, A., Heston, W., Larchian, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+orthotopic+models+for+bladder+cancer+research.">Mouse orthotopic models for bladder cancer research.</a> BJU Int. 104, 1286-1291 (2009).</li><li>Kubota, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metastatic+models+of+human+cancer+xenografted+in+the+nude+mouse:+the+importance+of+orthotopic+transplantation.">Metastatic models of human cancer xenografted in the nude mouse: the importance of orthotopic transplantation.</a> J. Cell. Biochem. 56, 4-8 (1994).</li><li>Hadaschik, B. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+validated+mouse+model+for+orthotopic+bladder+cancer+using+transurethral+tumour+inoculation+and+bioluminescence+imaging.">A validated mouse model for orthotopic bladder cancer using transurethral tumour inoculation and bioluminescence imaging.</a> BJU Int. 100, 1377-1384 (2007).</li><li>Kang, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Orthotopic+Bladder+Tumor+Model+and+the+Evaluation+of+Intravesical+saRNA+Treatment.">An Orthotopic Bladder Tumor Model and the Evaluation of Intravesical saRNA Treatment.</a> J. Vis. Exp. (65), (2012).</li><li>Dobek, G. L., Godbey, W. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Orthotopic+Model+of+Murine+Bladder+Cancer.">An Orthotopic Model of Murine Bladder Cancer.</a> J. Vis. Exp. (48), (2011).</li><li>Dinney, C. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+metastatic+variants+from+human+transitional+cell+carcinoma+passaged+by+orthotopic+implantation+in+athymic+nude+mice.">Isolation and characterization of metastatic variants from human transitional cell carcinoma passaged by orthotopic implantation in athymic nude mice.</a> J. Urol. 154, 1532-1538 (1995).</li><li>Fu, C., Apelo, C. A., Torres, B., Thai, K. H., Hsieh, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+Bladder+Wall+Injection.">Mouse Bladder Wall Injection.</a> J. Vis. Exp. (53), (2011).</li><li>Xiao, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+novel+transplantable+orthotopic+rat+bladder+transitional+cell+tumour+model.">Characterization of a novel transplantable orthotopic rat bladder transitional cell tumour model.</a> Br. J. Cancer. 81, 638-646 (1999).</li><li>Iinuma, S., Bachor, R., Flotte, T., Hasan, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodistribution+and+phototoxicity+of+5-aminolevulinic+acid-induced+PpIX+in+an+orthotopic+rat+bladder+tumor+model.">Biodistribution and phototoxicity of 5-aminolevulinic acid-induced PpIX in an orthotopic rat bladder tumor model.</a> J. Urol. 153, 802-806 (1995).</li><li>J&#228;ger, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hiding+in+plain+view:+Genetic+profiling+reveals+decades+old+cross-contamination+of+bladder+cancer+cell+line+KU7+with+HeLa.">Hiding in plain view: Genetic profiling reveals decades old cross-contamination of bladder cancer cell line KU7 with HeLa.</a> J. Urol. (13), (2013).</li><li>Horiguchi, Y., Larchian, W. A., Kaplinsky, R., Fair, W. R., Heston, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravesical+liposome-mediated+interleukin-2+gene+therapy+in+orthotopic+murine+bladder+cancer+model.">Intravesical liposome-mediated interleukin-2 gene therapy in orthotopic murine bladder cancer model.</a> Gene Ther. 7, 844-851 (2000).</li><li>Dinney, C. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+metastatic+variants+from+human+transitional+cell+carcinoma+passaged+by+orthotopic+implantation+in+athymic+nude+mice.">Isolation and characterization of metastatic variants from human transitional cell carcinoma passaged by orthotopic implantation in athymic nude mice.</a> J. Urol. 154, 1532-1538 (1995).</li><li>Black, P. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validating+bladder+cancer+xenograft+bioluminescence+with+magnetic+resonance+imaging:+the+significance+of+hypoxia+and+necrosis.">Validating bladder cancer xenograft bioluminescence with magnetic resonance imaging: the significance of hypoxia and necrosis.</a> BJU Int. 106, 1799-1804 (2010).</li></ol>

Open access for this video-article is sponsored by&#160;FUJIFILM VisualSonics, Inc.

Almost all major advances in cancer therapy will require testing in animal models before initiating clinical trials. Animal models of cancer are essential tools that enable researchers to study tumor biology in vivo. Orthotopic xenograft models remain the gold standard1,2 and continue to offer the most flexibility (in terms of selection of cell lines) and have the most practical utility.
The illustrated procedure is a minimally invasive modification of the orthotopic model previously described by Dinney et al.12 We established xenograft tumors by ultrasound guided percutaneous injection of three different cell lines with a technical success rate of 100%. During continuous follow-up, 98% of mice demonstrated constant increase in tumor volume.
By performing a minimally-invasive technique we were able to address existing limitations of the intramural model. Besides respecting animal welfare, the reduced invasiveness of this procedure also contributes to reproducibility of in vivo experiments by decreasing the number of surgical complications. It is highly time effective to avoid an abdominal laparotomy and associated need for wound closure. We were able to decrease significantly the procedure time per animal to 3.4 min (&#177;1.6). However, the chief advantage of our novel approach is its accuracy. High-resolution ultrasound allows us to visualize the space created by saline injection under the mucosa of the bladder wall. This first step injection facilitates tumor cell injection in a second step and minimizes the risk of tumor cell spillage. This contrasts to the technique of intramural injection after laparotomy, where it is impossible to visualize needle placement and there is always an element of uncertainty regarding the exact depth of injection. Also, as we are inoculating tumor cells strictly into the anterior bladder wall, tumor growth on the posterior bladder wall is avoided. Subsequently the rate of obstructive complications due to tumor growth in proximity of the ureteral orifices is extremely rare. This accompanying effect allows longer growth and treatment periods.
The main limitation of the ultrasound-guided tumor inoculation is the need for adequate technical equipment. Therefore the performance of this procedure will likely be restricted to centers which are specialized in animal models of human cancer. This should encourage collaborations between research groups outside of these institutions and the groups with expertise in such novel animal modeling.
Although dependent on familiarity with ultrasound imaging and some manual dexterity, this model is easy to learn under competent instruction. The key step in the procedure is the creation of an artificial space submucosally in the bladder wall with saline. Once this space is created without perforation of the mucosal layer, it remains stable for several minutes. The guidance of the second needle into this space in order to inoculate the tumor cells is relatively simple. The main complication during the creation of the submucosal space is perforation of the needle into the bladder lumen. The creation of a submucosal space, however, remains feasible. The needle has to be withdrawn slowly into the bladder wall and the saline injected just when the mucosal layer flips over the tip of the needle. After this maneuver the submucosal space is less stable (saline will escape to the bladder lumen within 30-60 sec) and the injection of the tumor cells has to be performed quickly. Spillage of tumor cells into the bladder lumen can occur in these cases with perforation of the mucosa. Although the loss of tumor cells from the intramural space might lead to a decreased tumor volume during follow-up, we have never observed any intravesical tumor uptake.
Another potential complication is the spillage of tumor cells to the peritoneal cavity through the injection channel. We observed only one intraperitoneal tumor cell dissemination in 50 animals, and this occurred in one of our first attempts. We attribute this to the injection of too large a tumor cell suspension volume. This was supported by the fact that reducing the volume from 50-40 &#181;l&#160;resulted in no further intraperitoneal spillage.
This minimally invasive inoculation of murine orthotopic bladder cancer xenograft represents an innovative modification of the existing &#8220;intramural model&#8221;, benefitting both the investigator and the animals equally. The advantages of this model encourage its adaptation to other organs such as kidney, prostate and liver in order to establish orthotopic xenograft tumors in a minimally-invasive fashion.

Cancer research is dependent on animal models of human cancer using cell lines derived from patient tumors in order to deepen our understanding of tumor biology. For in vivo growth analysis under different treatment strategies murine orthotopic bladder cancer models remain the reference standard1,2. The inoculation of human bladder cancer cells in immunocompromised mice (xenograft model) relies on intravesical instillation (&#8220;intravesical model&#8221;)3,4,5 or direct injection into the bladder wall (&#8220;intramural model&#8221;)6,7. Both techniques can also be performed in rats8,9.
Intravesical instillation induces the formation of tumors on the urothelial surface of the bladder which then are amenable to subsequent intravesical instillation of novel treatment agents. However, the number of cell lines which are reliably tumorigenic when delivered via this method is limited and one of those cell lines, KU7, has recently been demonstrated to be HeLa4,10. Intravesical instillation is also time consuming due to necessary dwell times, and it frequently induces tumor growth in adjacent elements of the urinary tract, including urethra, ureter, and renal pelvis11. Furthermore, intravesical instillation often leads to tumor growth on the floor of the bladder where the ureters enter the bladder, and this can cause upper tract obstruction and concomitant renal failure.
Primary invasive bladder cancer xenografts which are suitable for systemic treatments are created by direct injection of tumor cells into the bladder wall12. Although numerous cell lines grow adequately in this model, its limitation is the invasiveness of the model related to the need for an abdominal incision13. The model is also challenging to learn due to the technical difficulty of injecting cells precisely into the muscle wall of the bladder.
A novel approach to establish orthotopic primary invasive bladder cancer xenografts in mice has been developed in our department in order to address existing shortcomings of the &#8220;intramural model&#8221;. We were able to optimize the percutaneous, ultrasound-guided injection of bladder cancer cells into the anterior bladder wall resulting in this novel technique to successfully replace the established invasive model. Moreover we have potentially enhanced the accuracy and reproducibility of the &#8220;intramural model&#8221;.

<table border="0" cellpadding="0" cellspacing="0">
	<colgroup>
		<col span="4" />
	</colgroup>
	<tbody>
		<tr>
			<td>Chlorhexidine gluconate (2%)</td>
			<td>Aplicare</td>
			<td>82-319</td>
			<td></td>
		</tr>
		<tr height="121">
			<td height="121" style="height:121px;width:64px;">Dulbecco&#8217;s modified Eagle&#8217;s medium (DMEM)</td>
			<td style="width:64px;">Thermo Scientific</td>
			<td style="width:64px;">SH3008101</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="81">
			<td height="81" style="height:81px;width:64px;">Fetal bovine serum (FBS)</td>
			<td style="width:64px;">Thermo Scientific</td>
			<td style="width:64px;">SH3007103</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:64px;">Matrigel</td>
			<td style="width:64px;">BD Bioscience</td>
			<td align="right" style="width:64px;">356234</td>
			<td style="width:64px;">Keep between 2-4&#8304;C</td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:64px;">Isoflurane</td>
			<td style="width:64px;">Baxter Corporation</td>
			<td style="width:64px;">402-069-02</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:64px;">Trypsin (0.25%)</td>
			<td style="width:64px;">Thermo Scientific</td>
			<td style="width:64px;">SH3004202</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:64px;">Syringe (1ml)</td>
			<td style="width:64px;">BD Bioscience</td>
			<td align="right" style="width:64px;">309659</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="101">
			<td height="101" style="height:101px;width:64px;">Hypodermic needle (30G; &#190; inch)</td>
			<td style="width:64px;">Kendall</td>
			<td align="right" style="width:64px;">830340</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:64px;">Angiocatheter (24G)</td>
			<td style="width:64px;">BD Bioscience</td>
			<td align="right" style="width:64px;">381112</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="101">
			<td height="101" style="height:101px;width:64px;">Vevo 770 small animal imaging platform</td>
			<td style="width:64px;">VisualSonics</td>
			<td style="width:64px;"></td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="101">
			<td height="101" style="height:101px;width:64px;">RMV 706 ultrasound scanhead</td>
			<td style="width:64px;">VisualSonics</td>
			<td style="width:64px;"></td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:64px;">IVIS Lumina III</td>
			<td style="width:64px;">&#160;Caliper Life Science</td>
			<td style="width:64px;"></td>
			<td style="width:64px;"></td>
		</tr>
	</tbody>
</table>

minimally invasive establishment of murine orthotopic bladder xenografts

Orthotopic bladder cancer xenografts are the gold standard to study molecular cellular manipulations and new therapeutic agents&#160;in vivo. Suitable cell lines are inoculated either by intravesical instillation (model of nonmuscle invasive growth) or intramural injection into the bladder wall (model of invasive growth). Both procedures are complex and highly time-consuming. Additionally, the superficial model has its shortcomings due to the lack of cell lines that are tumorigenic following instillation. Intramural injection, on the other hand, is marred by the invasiveness of the procedure and the associated morbidity for the host mouse.
With these shortcomings in mind, we modified previous methods to develop a minimally invasive approach for creating orthotopic bladder cancer xenografts. Using ultrasound guidance we have successfully performed percutaneous inoculation of the bladder cancer cell lines UM-UC1, UM-UC3 and UM-UC13 into 50 athymic nude. We have been able to demonstrate that this approach is time efficient, precise and safe. With this technique, initially a space is created under the bladder mucosa with PBS, and tumor cells are then injected into this space in a second step. Tumor growth is monitored at regular intervals with bioluminescence imaging and ultrasound. The average tumor volumes increased steadily in in all but one of our 50 mice over the study period.
In our institution, this novel approach, which allows bladder cancer xenograft inoculation in a minimally-invasive, rapid and highly precise way, has replaced the traditional model.

Intramural injection of three different tumor cell lines (UM-UC1 luc, UM-UC3 luc and UM-UC13 luc) was performed in 50 animals under ultrasound-guidance on three consecutive days. The inoculation was performed efficiently (mean time 5.7 min/animal) and was not associated with any intra- or post-interventional complications.
Monitoring of tumor growth was performed by ultrasound imaging and bioluminescence. On day #3 a tumor could be detected by ultrasound in the anterior bladder of all 50 animals [Figure&#160;4 I]. 98% of mice showed constant tumor growth during the follow-up period [Figures&#160;4 and&#160;5]. Following the inoculation of UM-UC3 luc, one mouse developed intraperitoneal tumor dissemination and the tumor involuted after day #7 in a second animal [Table&#160;1]. This was the first group of mice inoculated with this new technique.
The mice were sacrificed on day #24, #28, and #37 after inoculation of UM-UC3 luc, UM-UC1 luc and UM-UC13 luc, respectively. Xenograft tumors were harvested and examined on hematoxylin and eosin (H&#38;E) sections. All tumors were muscle invasive and some infiltrated into the perivesical fat, but no invasion into adjacent organs was observed [Figure&#160;6 I]. 60% of mice bearing UM-UC13 luc tumors and 20% of mice bearing UM-UC3 luc tumors developed retroperitoneal lymph node metastases which were confirmed by H&#38;E staining [Figure&#160;6 II].
<img alt="Figure 1" fo:content-width="4in" fo:src="/files/ftp_upload/51123/51123fig1highres.jpg" src="/files/ftp_upload/51123/51123fig1.jpg" /> 
Figure 1.&#160;Image and schematic illustration of the experimental setup. The mouse is mounted on the heated operation table (I) and held under anaesthesia (II) with 3% isoflurane/oxygen mixture. The lower limbs are fixed with a rubber band (III). After approaching the ultrasound scanhead (IV) to the skin (longitudinal alignment with a cranial angle of 45-70&#176;) the bladder (V) is visualized on the ultrasound screen. A syringe with a 30 G needle (VI) is guided to the skin in an angle of 30-45&#176; (80-90&#176; relative to the longitudinal axis of the ultrasound scanhead).
<img alt="Figure 2" fo:content-width="5in" fo:src="/files/ftp_upload/51123/51123fig2highres.jpg" src="/files/ftp_upload/51123/51123fig2.jpg" /> 
Figure 2.&#160;Immobilization of the bladder. Dimensions and illustration to construct the bladder stabilization strap (I) The strap is attached to the lower abdomen and immobilizes the bladder (II). Thus an evasion of the bladder during intramural injection is avoided.
<img alt="Figure 3" fo:content-width="5in" fo:src="/files/ftp_upload/51123/51123fig3highres.jpg" src="/files/ftp_upload/51123/51123fig3.jpg" /> 
Figure 3.&#160;Intramural inoculation of tumor cells. Visualization of the bladder on the ultrasound screen (I). Perforation of the skin and abdominal wall muscles (II). Needle insertion into the bladder wall without penetration of the mucosa (III). PBS (50 &#181;l) between the muscular layer and the mucosa after slow injection (IV). Tumor cells suspended in Matrigel in the intramural artificially created space (V, VI).
<img alt="Figure 4" fo:content-width="5in" fo:src="/files/ftp_upload/51123/51123fig4highres.jpg" src="/files/ftp_upload/51123/51123fig4.jpg" /> 
Figure 4.&#160;Follow-up by ultrasound. Continuous follow-up by ultrasound showed significant increase in tumor volume (I: day #3, II: day #7, III: day #13).
<img alt="Figure 5" fo:content-width="5in" fo:src="/files/ftp_upload/51123/51123fig5highres.jpg" src="/files/ftp_upload/51123/51123fig5.jpg" /> 
Figure 5.&#160;Follow-up by bioluminescence. Continuous follow-up by bioluminescence showed constant increase in luminescence over the study period.
<img alt="Figure 6" fo:content-width="5in" fo:src="/files/ftp_upload/51123/51123fig6highres.jpg" src="/files/ftp_upload/51123/51123fig6.jpg" /> 
Figure 6.&#160;Histology of xenograft tumor and lymph node metastasis. In toto H&#38;E section of a representative xenograft tumor demonstrating invasive growth into the muscle without invasion into adjacent organs (I). 60% of mice bearing UM-UC13 luc tumors and 20% of mice bearing UM-UC3 luc tumors presented retroperitoneal lymph node metastases (II).
<table border="0" cellpadding="0" cellspacing="0" width="320">
	<tbody>
		<tr>
			<td>Inoculated cell line</td>
			<td></td>
			<td>UM-UC1 luc</td>
			<td>UM-UC3 luc</td>
			<td>UM-UC13 luc</td>
		</tr>
		<tr>
			<td>Number of mice</td>
			<td></td>
			<td>20</td>
			<td>15</td>
			<td>15</td>
		</tr>
		<tr>
			<td>Volume injected, &#181;L</td>
			<td></td>
			<td>40</td>
			<td>50</td>
			<td>50</td>
		</tr>
		<tr>
			<td>Cell count, absolute</td>
			<td></td>
			<td>3.6 x 105</td>
			<td>6 x 105</td>
			<td>5.5 x 105</td>
		</tr>
		<tr>
			<td>Time per animal, min&#160;</td>
			<td></td>
			<td>3.4 (&#177;1.6)</td>
			<td>7.7 (&#177;3.7)</td>
			<td>6.8 (&#177;2.9)</td>
		</tr>
		<tr>
			<td>Tumor incidence</td>
			<td></td>
			<td>49 (98%)</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td>20 (100%)</td>
			<td>14 (93%)</td>
			<td>15 (100%)</td>
		</tr>
		<tr>
			<td>Lymph node metastasis</td>
			<td></td>
			<td>0</td>
			<td>3 (20%)</td>
			<td>9 (60%)</td>
		</tr>
		<tr>
			<td>Follow up (days)</td>
			<td></td>
			<td>28</td>
			<td>22 [before treatment]</td>
			<td>28 [before treatment]</td>
		</tr>
		<tr>
			<td>Tumor volume (&#956;L)</td>
			<td>day 4</td>
			<td>11.6 (&#177;1.3)</td>
			<td>12.5 (&#177;1.7)</td>
			<td>14.4 (&#177;1.3)</td>
		</tr>
		<tr>
			<td></td>
			<td>end of</td>
			<td>394.6 (&#177;72.4)</td>
			<td>288.7 (&#177;66.1)</td>
			<td>78.3 (&#177;13.4)</td>
		</tr>
		<tr>
			<td>follow-up</td>
		</tr>
		<tr>
			<td>Tumor luminescence (Photons / sec)</td>
			<td>day 4</td>
			<td>4.6 x 108</td>
			<td>2.0 x 108</td>
			<td>5.8 x 108</td>
		</tr>
		<tr>
			<td>(&#177;9.4 x 107)</td>
			<td>(&#177;3.7 x 107)</td>
			<td>(&#177;1.3 x 108)</td>
		</tr>
		<tr>
			<td></td>
			<td>end of</td>
			<td>1.9 x 1010</td>
			<td>1.4 x 1010</td>
			<td>1.5 x 1010</td>
		</tr>
		<tr>
			<td>&#160;follow-up</td>
			<td>(&#177;4.0 x 109)</td>
			<td>(&#177;2.3 x 109)</td>
			<td>(&#177;1.9 x 109)</td>
		</tr>
	</tbody>
</table>
Table 1.&#160;Ultrasound-guided tumor cell injection - procedure and results.

Watch this Scientific Journal Video about Minimally Invasive Establishment of Murine Orthotopic Bladder Xenografts at JoVE.com

Minimally Invasive Establishment of Murine Orthotopic Bladder Xenografts

The established technique to inoculate primary invasive orthotopic bladder cancer xenografts requires laparotomy and mobilization of the bladder. This procedure inflicts significant morbidity on the mice, is technically challenging and time-consuming. We therefore developed a high-precision, percutaneous approach utilizing ultrasound guidance.

Orthotopic bladder cancer xenografts are the gold standard to study molecular cellular manipulations and new therapeutic agents&#160;in vivo. Suitable ...

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15.7K Views.  University of British Columbia. The established technique to inoculate primary invasive orthotopic bladder cancer xenografts requires laparotomy and mobilization of the bladder. This procedure inflicts significant morbidity on the mice, is technically challenging and time-consuming. We therefore developed a high-precision, percutaneous approach utilizing ultrasound guidance.

Video: Minimally Invasive Establishment of Murine Orthotopic Bladder Xenografts

An Orthotopic Model of Murine Bladder Cancer

In this straightforward procedure, bladder tumors are established in female C57 mice through the use of catheterization, local cauterization, and subsequent cell adhesion. After their bladders are transurethrally catheterized and drained, animals are again catheterized to permit insertion of a platinum wire into bladders without damaging the urethra or bladder. The catheters are made of Teflon to serve as an insulator for the wire, which will conduct electrical current into the bladder to create a burn injury. An electrocautery unit is used to deliver 2.5W to the exposed end of the wire, burning away extracellular layers and providing attachment sites for carcinoma cells that are delivered in suspension to the bladder through a subsequent catheterization. Cells remain in the bladder for 90 minutes, after which the catheters are removed and the bladders allowed to drain naturally. The development of tumor is monitored via ultrasound. Specific attention is paid to the catheterization technique in the accompanying video.

Bladder tumors are established in female mice in a minimally invasive fashion through catheterization, local cauterization, and subsequent adhesion of carcinoma cells to the burn sites.

In this straightforward procedure, bladder tumors are established in female C57 mice through the use of catheterization, local cauterization, and ...

An Orthotopic Bladder Tumor Model and the Evaluation of Intravesical saRNA Treatment

We present a novel method for treating bladder cancer with intravesically delivered small activating RNA (saRNA) in an orthotopic xenograft mouse bladder tumor model. The mouse model is established by urethral catheterization under inhaled general anesthetic. Chemical burn is then introduced to the bladder mucosa using intravesical silver nitrate solution to disrupt the bladder glycosaminoglycan layer and allows cells to attach. Following several washes with sterile water, human bladder cancer KU-7-luc2-GFP cells are instilled through the catheter into the bladder to dwell for 2 hours. Subsequent growth of bladder tumors is confirmed and monitored by in vivo bladder ultrasound and bioluminescent imaging. The tumors are then treated intravesically with saRNA formulated in lipid nanoparticles (LNPs). Tumor growth is monitored with ultrasound and bioluminescence. All steps of this procedure are demonstrated in the accompanying video.

Establishing an orthotopic bladder tumor model to evaluate antitumor effects of intravesically delivered saRNA and monitoring tumor growth by ultrasound and bioluminescent imaging.

We present a novel method for treating bladder cancer with intravesically delivered small activating RNA (saRNA) in an orthotopic xenograft mouse bladder ...

An Orthotopic Bladder Cancer Model for Gene Delivery Studies

Bladder cancer is the second most common cancer of the urogenital tract and novel therapeutic approaches that can reduce recurrence and progression are needed. The tumor microenvironment can significantly influence tumor development and therapy response. It is therefore often desirable to grow tumor cells in the organ from which they originated. This protocol describes an orthotopic model of bladder cancer, in which MB49 murine bladder carcinoma cells are instilled into the bladder via catheterization. Successful tumor cell implantation in this model requires disruption of the protective glycosaminoglycan layer, which can be accomplished by physical or chemical means. In our protocol the bladder is treated with trypsin prior to cell instillation. Catheterization of the bladder can also be used to deliver therapeutics once the tumors are established. This protocol describes the delivery of an adenoviral construct that expresses a luciferase reporter gene. While our protocol has been optimized for short-term studies and focuses on gene delivery, the methodology of mouse bladder catheterization has broad applications.

Implantation of cancer cells into the organ of origin can serve as a useful preclinical model to evaluate novel therapies. MB49 bladder carcinoma cells can be grown within the bladder following intravesical instillation. This protocol demonstrates catheterization of the mouse bladder for the purpose of tumor implantation and adenoviral delivery.

Bladder cancer is the second most common cancer of the urogenital tract and novel therapeutic approaches that can reduce recurrence and progression are ...

Primary Orthotopic Glioma Xenografts Recapitulate Infiltrative Growth and Isocitrate Dehydrogenase I Mutation

Malignant gliomas constitute a heterogeneous group of highly infiltrative glial neoplasms with distinct clinical and molecular features. Primary orthotopic xenografts recapitulate the histopathological and molecular features of malignant glioma subtypes in preclinical animal models. To model WHO grades III and IV malignant gliomas in transplantation assays, human tumor cells are xenografted into an orthotopic site, the brain, of immunocompromised mice. In contrast to secondary xenografts that utilize cultured tumor cells, human glioma cells are dissociated from resected specimens and transplanted without prior passage in tissue culture to generate primary xenografts. The procedure in this report details tumor sample preparation, intracranial transplantation into immunocompromised mice, monitoring for tumor engraftment and tumor harvesting for subsequent passage into recipient animals or analysis. Tumor cell preparation requires 2 hr and surgical procedure requires 20 min/animal.

Malignant gliomas constitute a heterogeneous group of highly infiltrative glial neoplasms with distinct clinical and molecular features. Primary orthotopic xenografts recapitulate the histopathological and molecular features of malignant glioma subtypes in preclinical animal models.

Malignant gliomas constitute a heterogeneous group of highly infiltrative glial neoplasms with distinct clinical and molecular features. Primary ...

Evaluation of the Efficacy of the H. pylori Protein HP-NAP as a Therapeutic Tool for Treatment of Bladder Cancer in an Orthotopic Murine Model

Bladder cancer is one of the most common malignancies of the urogenital tract. Intravesical injection of Bacillus Calmette-Gu&#233;rin (BCG) is the gold standard treatment for the high-grade non-muscle invasive bladder cancer (NMIBC). However, since the treatment-related side effects are relevant, newer biological response modifiers with a better benefit/side effects ratio are needed.
The tumour microenvironment can influence both tumour development and therapy efficacy. In order to obtain a good model, it is desirable to implant tumour cells in the organ from which the cancer originates.
In this protocol, we describe a method for establishing a tumour in the bladder cavity of female mice and subsequent delivery of therapeutic agents; the latter are exemplified by our use of Helicobacter pylori neutrophil activating protein (HP-NAP). A preliminary chemical burn of the mucosa, followed by the injection of mouse urothelial carcinoma cell line MB49 via urethral catheterization, enables the cells to attach to the bladder mucosa. After a period, required to allow an initial proliferation of the cells, mice are treated with HP-NAP, administrated again via catheterization. The anti-tumour activity of HP-NAP is evaluated comparing the tumour volume, the extent of necrosis and the degree of vascularization between vehicle- and HP-NAP-treated animals.

Evaluation of the Efficacy of the H. pylori Protein HP-NAP as a Therapeutic Tool for Treatment of Bladder Cancer in an Orthotopic Murine Model

Here the method to establish a syngeneic mouse model of orthotopic bladder tumour to evaluate the anti-tumour efficacy of the bacterial protein HP-NAP is described.

Bladder cancer is one of the most common malignancies of the urogenital tract. Intravesical injection of Bacillus Calmette-Gu&#233;rin (BCG) is the gold ...

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.

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

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

An Anatomical Study of Nerves at Risk During Minimally Invasive Hallux Valgus Surgery

The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional orientation and localization of structures that are not directly visible to the surgeon. This is especially critical for structures at risk like nerves or blood vessels. Optimization of the handling of cadaveric material and the combination of multiple techniques compensate for the limited availability of adequate specimens. The described protocol combines anatomical plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to help localize relevant structures, such as nerves, arteries, veins and to correctly position the portals during MIS procedures. Depiction of these structures in anatomy textbooks can differ from what is encountered in the surgical field; and for this reason, new anatomical studies with a surgical orientation are needed. However, this is a complex, time-consuming technique requiring specific training. The anatomical references described with the so-called 'clock method' provide the surgeon with an easy and reproducible system to locate the path of the nerves at risk in Hallux Valgus MIS procedures. This model can be extrapolated to many other minimally invasive surgical procedures.

Minimally invasive surgical (MIS) procedures rely on anatomical references to localize structures not directly visible to the surgeon. This manuscript describes a combined method of plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to locate the structures at risk during MIS procedures.

The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional ...

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Presented here is a protocol for lung nodule localization using dye marking via electromagnetically navigated transthoracic needle access. The technique described here can be accomplished in the peri-operative period to optimize nodule localization and to successful resection when performing minimally invasive thoracic surgery.

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...